Category Archives: Neuroscience

The Yack on NAC (N-Acetyl-Cysteine) and Parkinson’s

“Once you choose hope, anything’s possible.” Christopher Reeve

“Hope is like a road in the country; there was never a road, but when many people walk on it, the road comes into existence.” Lin Yutang

Introduction: N-Acetyl-Cysteine (or N-acetylcysteine, usually abbreviated NAC and frequently pronounced like the word ‘knack’) is an altered (modified by an N-acetyl-group) form of the sulfur-containing amino acid cysteine (Cys).  NAC is one of the building blocks for the all important antioxidant substance glutathione (GSH).   GSH is a powerful reagent that helps cells fight oxidative stress.  One of the putative causes of Parkinson’s is oxidative stress on dopamine-producing neurons (see figure below). This post summarizes some of the biochemistry of NAC and GSH.  Furthermore, NAC may provide some neuroprotective benefit as a complementary and alternative medicine (CAM) approach to treating Parkinson’s.

“Losing the possibility of something is the exact same thing as losing hope and without hope nothing can survive.” Mark Z. Danielewski

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 Glutathione (GSH):  GSH is a 3-amino acid substance (tripeptide) composed of Cys linked to glutamate (Glu) and followed by glycine (Gly). NAC would need to be de-acetylated to provide Cys and that would feed in to the reaction synthesis. Importantly, Cys is the rate limiting reactant, which means without adequate amounts of Cys you do not make GSH.   The schematic below gives the orientation and order of addition of the three amino acid components to give you GSH.

NACtoGSH

There are two advantages of NAC over Cys for making GSH: (i) the sulfhydryl group of NAC remains reduced (that is as an SH group) more so than the SH group of Cys; and (ii) the NAC molecule appears to transport itself through cell membranes much more easily than Cys.  The reduced (i.e.,  free SH group) form of GSH, once synthesized within the cell, has several key functions that range from antioxidant protection to protein thiolation to drug detoxification in many different tissues.   The key function of GSH is to provide what is known as “reducing equivalents” to the cell, which implies an overall key antioxidant effect.

The schematic below shows NAC transport from extracellular to intracellular (inside the cell), and the primary reactions for detoxification and thiolation from GSH. Implied by this figure below is that GSH is not easily transported into the cell. Furthermore, in a more toxic/hostile environment outside of the cell, you can easily oxidize 2 GSH molecules to become GSSG (the reduced SH group gets oxidized to form an S-S disulfide bond) and GSSG does not have the antioxidant effect of GSH.   However, inside the cell, GSH is a very potent antioxidant/detoxifying substance. And the beauty of being inside the cell, there is an enzyme called GSH-reductase that regenerates GSH from GSSG.

Rushworth-NAC.review-4.2

To recap and attempt to simplify what I just said, NAC gets delivered into a cell, which then allows the cell to generate intracellular GSH.  The presence of intracellular GSH gives a cell an enormous advantage to resist potentially toxic oxidative agents. By contrast, extracellular GSH has a difficult path into the cell; and is likely to be oxidized to GSSG and rendered useless to help the cell.

“Just remember, you can do anything you set your mind to, but it takes action, perseverance, and facing your fears.”  Gillian Anderson

One of many biological functions of NAC:   Perhaps the most important medical use of NAC is to help save lives in people with acetaminophen toxicity, in which the liver is failing.  How does NAC do this?  Acetaminophen is sold as Tylenol.  It is also added to compounds that are very important for pain management ()analgesics), including Vicodin and Percocet. Acetaminophen overdose is the leading cause of acute liver failure in the USA.   This excess of acetaminophen rapidly consumes the GSH in the liver, which then promotes liver death.  NAC quickly restores protective levels of GSH  to the liver, which hopefully reverses catastrophic liver failure to prevent death.

Systemically, when taken either orally or by IV injection, NAC would have 2 functions.  First, NAC replenishes levels of Cys to generate the intracellular antioxidant GSH (see schemes above).  Second, NAC has been shown to regulate gene expression of several pathways that link oxidative stress to inflammation.  Since the primary goal of this post relates to NAC as a CAM in Parkinson’s, I will not expand further on the many uses of NAC in other disease processes.  However, listed at the end are several review articles detailing the numerous medicinal roles of NAC.

“Love, we say, is life; but love without hope and faith is agonizing death.” Elbert Hubbard

Use of NAC as a CAM in Parkinson’s:   This is what we know about oxidative stress in Parkinson’s and the potential reasons why NAC could be used as a CAM in this disorder, it goes as follows  (it’s also conveniently shown in the figure at the bottom):

1. Substantia nigra dopamine-producing neurons die from oxidative stress, which can lead to Parkinson’s.

2.What is oxidative stress? Oxidative stress happens when your cells in your body do not make/have enough antioxidants to reduce pro-oxidants like free radicals. Free radicals cause cell damage/death when they attack proteins/cell membranes.

3.We speak of oxidative stress in terms of redox imbalance (which means the balance between increased amounts of oxidants or  decreased amounts of antioxidants).

4.Glutathione (GSH) is a key substance used by cells to repair/resist oxidatively damaged cells/proteins.

5.”Forces of evil” in the brain that make it difficult to resist oxidative stress:  decreased levels of GSH,  increased levels of iron and  increased polyunsaturated fatty acids.

6.Extracellar GSH cannot be transported easily into neurons, although there is evidence GSH gets past the blood brain barrier;

7.N-acetyl Cysteine (NAC), is an anti-oxidant and a precursor to GSH.  NAC gets through the blood brain barrier and can also be transported into neurons.

8.Cysteine is the rate-limiting step for GSH synthesis (NAC would provide the cysteine and favor synthesis of GSH).

9.Animal model studies have shown NAC to be neuroprotective.

10. Recent studies have shown NAC crosses the human blood brain barrier and may be a useful PD-modifying therapy.

 

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“You cannot tailor-make the situations in life but you can tailor-make the attitudes to fit those situations.”  Zig Ziglar

Scientific and clinical support for NAC in treating Parkinson’s: Content presented here is meant for informational purposes only and not as medical advice.  Please remember that I am a basic scientist, not a neurologist, and any use of these compounds should be thoroughly discussed with your own personal physician. This is not meant to be an endorsement  because it would be more valuable and important for your neurologist to be in agreement with the interpretation of these papers.

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To evaluate the use of NAC in Parkinson’s, Katz et al. treated 12 patients with Parkinson’s with oral doses of NAC twice a day for two days.   They studied three different doses of 7, 35, and 70 mg per kilogram. For example, in a person weighing 170 pounds, from a Weight Based Divided Dose Calculator (click here), this would be 540, 2700, and 5400 mg/day of NAC for 7, 35, and 70 mg/kg, respectively. Using cerebral spinal fluid (CSF), they measured levels of  NAC, Cys, and GSH at baseline and 90 minutes after the last dose. Their results showed that there was a dose-dependent range of NAC as detected by CSF. And they concluded that oral administration of NAC produce biologically relevant CSF levels of NAC at the three doses examined; the doses of oral NAC were also well-tolerated.  Furthermore, the patients treated with NAC had no change in either motor or cognitive function. Their conclusions support the feasibility of using oral NAC as a CAM therapy for treatment of Parkinson’s.

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In a separate study, Monti at al  presented some preliminary evidence for the use of NAC in Parkinson’s. The first part of their study consisted of a neuronal cell system that was pre-treated with NAC in the presence of the pesticide rotenone as a model of Parkinson’s.   These results showed that with NAC there was more neuronal cell survival after exposure to rotenone compared to the rotenone-treated cells without NAC. The second part of the study was a small scale clinical evaluation using NAC in Parkinson’s. These patients were randomized and given either NAC or nothing and continued to use their traditional medical care. The patients were evaluated at the start and after three months of receiving NAC; they measured dopamine transporter binding and  performed the unified Parkinson’s disease rating scale  (UPDRS) to measure clinical symptoms. The clinical study revealed an increase in dopamine transporter binding in the NAC treatment group and no measurable changes in the control group. Furthermore UPDRS scores were significantly improved in the NAC treatment group compared to the control patient group.   An interesting feature of this study was the use of pharmaceutical NAC, which is an intravenous (IV) medication and they also used 600 mg NAC tablets. The dose used was 50 mg per kg mixed into sterile buffer and infused over one hour one time per week. In the days they were not getting the IV NAC treatment, subjects took 600 mg NAC tablets twice per day.

 Okay, what did I just say? I will try to summarize both of these studies in a more straightforward manner.   The results above suggest that NAC crosses the blood brain barrier and does offer some anti-oxidative protection. In one study, this was shown by increased levels of both GSH and Cys dependent on the NAC dose. In another study, they directly measured dopamine transporter binding, which was increased in the presence of NAC. In the second study using a three month treatment strategy with NAC, there was a measurable positive effect on disease progression as measured by UPDRS scores.  

“Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.” Thomas A. Edison

Potential for NAC in treating Parkinson’s: Overall, both studies described above suggest the possibility that NAC may be useful in treating Parkinson’s. However, in both cases these were preliminary studies that would require much larger randomized double-blind placebo-controlled trials to definitively show a benefit for using NAC in treating Parkinson’s. On a personal note, I have been taking 600 mg capsules of NAC three times a day for the past year with the hope that it is performing the task as outlined in this post. Using information from the first study that would be a NAC dose of 24 mg per kilogram body weight. In conclusion, the information described above suggests that NAC may be useful in regulating oxidative stress, one of the putative causes of Parkinson’s. As with all studies, time will tell if ultimately there is a benefit for using NAC in Parkinson’s.

“I am not an optimist, because I am not sure that everything ends well. Nor am I a pessimist, because I am not sure that everything ends badly. I just carry hope in my heart. Hope is the feeling that life and work have a meaning. You either have it or you don’t, regardless of the state of the world that surrounds you. Life without hope is an empty, boring, and useless life. I cannot imagine that I could strive for something if I did not carry hope in me. I am thankful to God for this gift. It is as big as life itself.” Vaclav Havel

References Used:
Katz M, Won SJ, Park Y, Orr A, Jones DP, Swanson RA, Glass GA. Cerebrospinal fluid concentrations of N-acetylcysteine after oral administration in Parkinson’s disease. Parkinsonism Relat Disord. 2015;21(5):500-3. doi: 10.1016/j.parkreldis.2015.02.020. PubMed PMID: 25765302.

Martinez-Banaclocha MA. N-acetyl-cysteine in the treatment of Parkinson’s disease. What are we waiting for? Med Hypotheses. 2012;79(1):8-12. doi: 10.1016/j.mehy.2012.03.021. PubMed PMID: 22546753.

Monti DA, Zabrecky G, Kremens D, Liang TW, Wintering NA, Cai J, Wei X, Bazzan AJ, Zhong L, Bowen B, Intenzo CM, Iacovitti L, Newberg AB. N-Acetyl Cysteine May Support Dopamine Neurons in Parkinson’s Disease: Preliminary Clinical and Cell Line Data. PLoS One. 2016;11(6):e0157602. doi: 10.1371/journal.pone.0157602. PubMed PMID: 27309537; PMCID: PMC4911055.

Mosley RL, Benner EJ, Kadiu I, Thomas M, Boska MD, Hasan K, Laurie C, Gendelman HE. Neuroinflammation, Oxidative Stress and the Pathogenesis of Parkinson’s Disease. Clin Neurosci Res. 2006;6(5):261-81. doi: 10.1016/j.cnr.2006.09.006. PubMed PMID: 18060039; PMCID: PMC1831679.

Nolan YM, Sullivan AM, Toulouse A. Parkinson’s disease in the nuclear age of neuroinflammation. Trends Mol Med. 2013;19(3):187-96. doi: 10.1016/j.molmed.2012.12.003. PubMed PMID: 23318001.

Rushworth GF, Megson IL. Existing and potential therapeutic uses for N-acetylcysteine: the need for conversion to intracellular glutathione for antioxidant benefits. Pharmacol Ther. 2014;141(2):150-9. doi: 10.1016/j.pharmthera.2013.09.006. PubMed PMID: 24080471.

Taylor JM, Main BS, Crack PJ. Neuroinflammation and oxidative stress: co-conspirators in the pathology of Parkinson’s disease. Neurochem Int. 2013;62(5):803-19. doi: 10.1016/j.neuint.2012.12.016. PubMed PMID: 23291248.

Cover photo credit: https://s-media-cache-ak0.pinimg.com/originals/e8/33/ae/e833aeb408a432d419628c803bf14498.jpg

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“Go the Distance” With MAO-B Inhibitors: Potential Long-term Benefits in Parkinson’s

“Life is 10 percent what you make it, and 90 percent how you take it.” Irving Berlin

“My attitude is that if you push me towards something that you think is a weakness, then I will turn that perceived weakness into a strength.” Michael Jordan

Précis:  (1) A brief review of the major classes of therapeutic compounds for treating Parkinson’s. (2) Defining clinical trials.  (3) Hauser et al.(Journal of Parkinson’s Disease vol. 7, no. 1, pp. 117-127, 2017) report that Parkinson’s patients who received an MAO-B inhibitor for a long period of time had statistically significant slower decline in their symptoms compared to patients not on an MAO-B inhibitor (click here to see paper). (4) Addendum: “New Kid In Town”, The FDA approves another MAO-B inhibitor named Xadago (safinamide). 

Pharmacological treatment of Parkinson’s [Please note that these views and opinions expressed here are my own. Content presented here is not meant as medical advice. Definitely consult with your physician before taking any type of drug.]: The management of Parkinson’s is broadly divided up into motor and non-motor therapy.  A brief description of the therapy for motor dysfunction will be presented here.  Please see the drawing below for an overview.   Within the framework of treating someone with Parkinson’s you must consider managing their symptoms with the hope that some compound might possess either  neuroprotective or neurorestorative actions. To date, we do not have a cure for Parkinson’s but the study described below suggests an existing compound may be neuroprotective when used for a long  time.

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“Things turn out best for the people who make the best of the way things turn out.” John Wooden

Medical management of the motor-related symptoms of Parkinson’s:

Levodopa, together with carbidopa, is the ‘gold standard’ of treatment of motor signs and symptoms. Carbidopa is  a peripheral decarboxylase inhibitor (PDI), which provides for an increased uptake of levodopa in the central nervous system. As shown above, levodopa (denoted as L-DOPA) is converted to dopamine by the dopaminergic neurons. Levodopa is still the most effective drug for managing Parkinson’s motor signs and symptoms. Over time, levodopa use is associated with issues of “wearing-off” (motor fluctuation) and dyskinesia.  For further information about levodopa and dopamine, please see this previously posted topic (click here).

Catechol-O-methyl transferase (COMT) inhibitors prolong the half-life of levodopa by blocking its metabolism. COMT inhibitors are used primarily to help with the problem of the ‘wearing-off’ phenomenon associated with levodopa.

Dopamine agonists are ‘mimics’ of dopamine that pass through the blood brain barrier to interact with target dopamine receptors. Dopamine agonists provide symptomatic benefit and delay the development of dyskinesia compared to levodopa.  Dopamine agonists are not without their own side-effects, which can occur in some patients, and include sudden-onset sleep, hallucinations, edema, and impulse  behavior disorders.  For more information about dopamine agonists,  please see this previously posted (click here).

Finally, monoamine oxidase (MAO)-B is an enzyme that destroys dopamine; thus, MAO-B inhibitors help prevent the destruction of dopamine in the brain. MAO-B inhibitors have some ability to reduce the symptoms of Parkinson’s. The most common severe side effects of MAO-B inhibitors include constipation, nausea, lightheadedness, confusion, and hallucinations.  There may also be contraindications between MAO-B inhibitors with other prescription medications,  vitamins, and certain foods/drinks (e.g., aged cheese and wine). Definitely talk to your doctor and pharmacist about potential drug interactions if you are considering an MAO-B inhibitor in your therapeutic regimen.

“You should just do the right thing.” Dean Smith

What are clinical trials? The simple description is that a clinical trial determines if a new test or treatment works and is safe. The National Institutes of Health (NIH) defines a clinical trial (paraphrased here) as a research study where human subjects are prospectively assigned1 to one or more interventions2 (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.[1The term “prospectively assigned” refers to a predefined process (e.g., randomization) in an approved protocol that stipulates the assignment of research subjects (individually or in clusters) to one or more arms (e.g., intervention, placebo, or other control) of a clinical trial.2An intervention is defined as a manipulation of the subject or subject’s environment for the purpose of modifying one or more health-related biomedical or behavioral processes and/or endpoints.  3Health-related biomedical or behavioral outcome is defined as the prespecified goal(s) or condition(s) that reflect the effect of one or more interventions on human subjects’ biomedical or behavioral status or quality of life.]  For the complete NIH definition, please click here.

As described by ‘ClinicalTrials.gov’, clinical trials are performed in phases; each phase attempts to answer a separate research question. Phase I: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects. Phase II: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.Phase III:  The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely. Phase IV: Studies are done after the drug or treatment has been marketed to gather information on the drug’s effect in various populations and any side effects associated with long-term use. A more complete description is included here (click here).

What is important to remember is that clinical trials are experiments with unknown outcomes that must follow a rigorous approach to safely evaluate and possibly validate potential treatments.

“Nothing has ever been accomplished in any walk of life without enthusiasm, without motivation, and without perseverance.” Jim Valvano

NET-PD-LS1 clinical trial went bust on creatine use in treating Parkinson’s: The NET-PD-LS1 clinical trial went from March 2007 until July 2013. NET-PD-LS1 was a multicenter, double blind, placebo-controlled trial of 1741 people with early Parkinson’s. The goal of NET-PD-LS1 was to determine if creatine could slow long-term clinical progression of Parkinson’s (to learn more about this clinical trial go here or go here) . NET-PD-LS1 was one of the largest and longest clinical trials  on Parkinson’s . This clinical trial was stopped after determining there was no benefit to using creatine to treat Parkinson’s.

“It’s what you learn after you know it all that counts.” John Wooden

NET-PD-LS1 clinical trial gets a ‘gold star’ for MAO-B inhibitors in treating Parkinson’s: NET-PD-LS1 was  a thorough and well organized clinical trial.  New results have been published in a secondary analysis of the clinical trial to determine if MAO-B inhibitors for an extended time affected the symptoms of Parkinson’s. Almost half (784) of the patients in NET-PD-LS1 took an MAO-B inhibitor. The MAO-B inhibitors used in NET-PD-LS1 were Rasagiline (Brand name Azilect) and Selegiline (Brand names Eldepryl, Zelapar, or EMSAM).  More than 1600 of the patient’s completed both baseline and one year evaluation/assessment measuring changes in their symptoms (this was done using a combination of five different measurement scales/systems).  Their results were exciting; the patients that were taking an MAO-B inhibitor for a longer time (1 year) had a slower clinical decline (~20% benefit in the magnitude of the decline compared to the patients not taking an MAO-B inhibitor).  These results indicate that MAO-B inhibitors  somehow are able to slow the progression of the symptoms of Parkinson’s.

“Always look at what you have left. Never look at what you have lost.” Robert H. Schuller

Does this prove that MAO-B inhibitors are neuroprotective in Parkinson’s?   The hopeful person inside of me  wants this answer to be yes; however, the scientist that also resides inside of me says no not quite yet.  The goal of neuroprotection is to slow or block or reverse progression of Parkinson’s; and by measuring changes in dopamine-producing neurons.  Early basic science results with MAO-B inhibitors found some neuroprotection in model systems. This new publication reignites the storyline that MAO-B inhibitors are potentially neuroprotective.

“Efforts and courage are not enough without purpose and direction.” John F. Kennedy

A personal reflection about the strategy for treatment of Parkinson’s: MAO-B inhibitors have never been part of my strategy for treating my disorder. I have been using a traditional drug therapy  protocol [Sinemet and Ropinirole] (click here),  supplemented by a  relatively comprehensive CAM approach (click here), bolstered hopefully by a neuroprotective (experimental) agent [Isradipine] (click here), and fortified with as much exercise in my day that my life can handle (click here).  However, there is a constant and dynamic flux/flow of ideas regarding treatment options for Parkinson’s. Thus,  my strategy for treating my disorder needs to be fluid and not fixed in stone. Over the next few weeks, I will be reading more about MAO-B inhibitors, having some serious conversations with my Neurologist and Internist,  with my care partner assessing the risk and benefits of taking an MAO-B inhibitor, and coming up with a consensus team opinion about whether or not I should start taking an MAO-B inhibitor.

Addendum- FDA Approves Xadago for Parkinson’s Disease:
As the Eagles sing in New Kid In Town, “There’s talk on the street; it sounds so familiar / Great expectations, everybody’s watching you”. The first new drug in a decade to treat Parkinson’s is an MAO-B inhibitor named Xadago (Safinamide).  This drug has an interesting past with the FDA before getting approved this week. Is it different? Xadago is for patients using levodopa/carbidopa that are experiencing troublesome “off episodes”, where their symptoms return despite taking their medication. Thus, Xadago is being marketed as an add-on therapy, which is different than existing MAO-B inhibitors because they can be used as stand alone monotherapy. In two separate clinical trials for safety and efficacy of Xadago, compared to patients taking placebo, those taking Xadago showed more “on” time and less “off” time. Interestingly, this is exactly what you’d expect for an MAO-B inhibitor  (sustaining dopamine, see drawing above).  The most common adverse side-effects reported were uncontrolled involuntary movement (side-note: isn’t this what we’re trying to prevent in the first place?), falls, nausea, and insomnia. Clearly, taking Xadago with another MAO-B inhibitor would not be good. Xadago joins a list of other MAO-B inhibitors that are FDA approved for Parkinson’s including Selegiline (Eldepryl, Zelapar, EMSAM) and Rasagiline (Azilect). Whether the efficacy of Xadago is different or improved from existing MAO-B inhibitors remains to be shown; however, having another MAO-B inhibitor may allow Parkinson’s patients the possibility to use the one with the least adverse reactions.  Clearly, close consultation with your Neurologist will be very important before adding any MAO-B inhibitor to your daily arsenal of drugs.  The good news is now you’ve got another option to join the stable of possible MAO-B inhibitors to be used with levodopa/carbidopa.

For the background/rationale behind using “Go the distance” in the title, watch this video clip: Field of Dreams (3/9) Movie CLIP – Go the Distance (1989) HD by Movieclips  (click here to watch Go the Distance).

“Only the mediocre are always at their best. If your standards are low, it is easy to meet those standards every single day, every single year. But if your standard is to be the best, there will be days when you fall short of that goal. It is okay to not win every game. The only problem would be if you allow a loss or a failure to change your standards. Keep your standards intact, keep the bar set high, and continue to try your very best every day to meet those standards. If you do that, you can always be proud of the work that you do.” Mike Krzyzewski

Cover photo image: https://img1.10bestmedia.com/Images/Photos/304499/Pier-orange-sky-compressed_54_990x660.jpg

Dopamine neurons for the drawing wermodified from http://www.utsa.edu/today/images/graphics/dopamine.jpg

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2016: The Year in Parkinson’s

“The most beautiful experience we can have is the mysterious. It is the fundamental emotion that stands at the cradle of true art and true science.” Albert Einstein

“Your assumptions are your windows on the world. Scrub them off every once in a while, or the light won’t come in.” Isaac Asimov

Summary: (Part 1) A brief review of my year with Parkinson’s. (Part 2) An overview of 12 scientific research studies on Parkinson’s from 2016.

Part 1. A personal Parkinson’s 2016 calendar review

Life with Parkinson’s: 706 days ago I started this blog ‘Journey with Parkinson’s’; and it’s been a remarkable journey through time since then.  Life is full, rarely a dull moment.  Dealing with a disorder like Parkinson’s is difficult because it slowly creeps around your body, somewhat stealth by nature but always ever present.  It requires a daily inventory of body movements, mental capacity and overall self-feelings compared to the day-week-month-year before.

Life is loving, fun, intellectually challenging, active, full, rarely a moment off; however, its best that way for me.  I close this paragraph by repeating two quotes from last year. They remind me to simply try to live as best as I am able for as long as I can.  My hope for you is likewise as well; keep going, keep working, stay active, stay the course.  Please make a manageable life-plan/contract with your care-partner, family and close friends; keep going, and please don’t give up.

“Never confuse a single defeat with a final defeat.” F. Scott Fitzgerald

“If you fell down yesterday, stand up today.” H.G. Wells

My year with Parkinson’s: To highlight my 2016, I’ve chosen 1 event/month to describe (not mentioned are the trips to the beach/vacation with Barbara, golf with the golf buddies, and other activities related to education, research and outreach for Parkinson’s.)  I am a very fortunate person.

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January-June, 2016:
(JAN) The 22nd year/class of undergraduates taking my spring semester course on ‘Biology of Blood Diseases’, great fun!
(FEB) An anniversary dinner with Barbara, a most loving person and the best care-partner.
(MAR) Started work on the WPC Parkinson Daily (eNewspaper) for the World Parkinson Congress).
(APR) Compiled all of the quotes from the students in class that led to the Kindle version (2016)/Paperback version (2017) of “A Parkinson’s Reading Companion”  (Click here to read about it).
(May) Graduation ceremonies are always on Mother’s Day weekend; it is filled with joy and regalia, promise and the future ahead for all of the graduates (typically, I attend the medical school ceremony on Saturday and as many undergraduate ceremonies on SAT-SUN my schedule permits (picture above is from the Dept. Biology commencement).
(JUN) A weekend in the Smoky Mountains in Asheville, NC: to attend a Parkinson’s retreat, to relax-renew-play golf, and to get a second Parkinson’s-related tattoo.

“Be happy for this moment. This moment is your life.” Omar Khayyam

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July-December, 2016:
(JUL) A weekend in Greenville, SC to participate and get certified in PWR! (Parkinson Wellness Recovery); an amazing experience (click here to read blog post about it).
(AUG) Truly a professional highlight of my career being chosen by the medical students to deliver the 2016 Richard H. Whitehead Lecture (click here to read blog post about it).
(SEP) Attended and presented a poster at the 4th World Parkinson Congress (WPC) in Portland, OR (click here to read about the WPC).
(OCT) Moving Day® NC Triangle, National Parkinson Foundation; great team and such a fun day/experience (click here to read about NC Triangle Moving Day).
(NOV) Research proposal submitted on the role of proteases and their inhibitors, alpha-synuclein and exercise in Parkinson’s. It is something I’ve been thinking about all of last year (click here to read about the funding program).
(DEC) Finished teaching the 3rd class of the Honor’s-version and fall semester of the undergraduate ‘Biology of Blood Diseases’ course; a great honor for me.

“Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful.” Albert Schweitzer

Part 2. The year (2016) in Parkinson’s science

Parkinson’s with a hopeful future: To live successfully with a chronic and progressing neurodegenerative disorder like Parkinson’s requires much, but in the least it takes hope.  We must remain hopeful that advances in Parkinson’s treatment are being made and that our understanding of the science of Parkinson’s is continuing to evolve.

Parkinson’s research: Parkinson’s is the most prevalent neurodegenerative movement disorder.  According to PubMed, there were 6,782 publications in 2016 that used “Parkinson’s disease” in the Title/Abstract.  Likewise in 2016, PubMed had 9,869 and 1,711 citations on Alzheimer’s disease and on Amyotrophic Lateral Sclerosis (ALS), respectively. Most research studies move in incremental steps; we describe a hypothesis and collect the data to hopefully advance us forward.

2016, the year in Parkinson’s: To remind us of some of these forward steps in Parkinson’s research, and to add to our base-level of hope, here are 12 projects from 2016 regarding Parkinson’s (there are several studies, not mentioned here, that I’m currently working on for individual blog posts because they seemed super-relevant and in need of more thorough presentation/explanation).  Although 12 is a minuscule list of citations/work reported from last year, it reinforces a simple notion that our trajectory is both positive and hopeful.

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January, 2016: Dipraglurant FDA-approved to treat dyskinesia. After ~5 years of treatment with the ‘gold-standard’ Levodopa/Carbidopa, many people-with-Parkinson’s develop drug-induced involuntary movement (also called dyskinesia).  This can be a serious side-effect of levodopa, and it can lead to numerous detrimental consequences.  The pharmaceutical company, Addex Therapeutics, has received orphan drug status for their drug named Dipraglurant, which will be used for the treatment of levodopa-induced dyskinesia.  Click here to read about the putative molecular mechanism of Dipraglurant, what advantages Addex gains from the designated orphan-drug status, and for more information about Addex.

“January is here, with eyes that keenly glow, A frost-mailed warrior striding a shadowy steed of snow.” Edgar Fawcett

February, 2016: Early detection of Parkinson’s from mouth salivary gland biopsy.   There is no definitive test to identify Parkinson’s in its early stages.  Finding an easily accessible tissue for  biopsy  to help with the diagnosis would be of value.  From autopsy samples, the submandibular saliva glands in the mouth seemed to be a relevant and easily accessible site to study.  The test involved inserting a needle into the submandibular salivary gland under the jaw,  staining for modified-a-synuclein.   The results revealed  that Parkinson’s patients had  increased level of a-synuclein  compared to patients  without Parkinson’s.  Click here to view this paper: Adler, Charles H. et al. “Peripheral Synucleinopathy in Early Parkinson’s Disease: Submandibular Gland Needle Biopsy Findings.” Movement disorders : official journal of the Movement Disorder Society 31.2 (2016): 250–256. PMC. Web. 13 Feb. 2017.

“Even though February was the shortest month of the year, sometimes it seemed like the longest.” Lorraine Snelling

March, 2016:  Three-dimensional scaffold used  to grow neuronal cells for transplant to brain.  Scientists have been able to convert adult stem cells into neuronal cells by culturing the stem cells in three-dimensional  scaffolding.   There are many obstacles successfully using stem cells to treat Parkinson’s disease; one of them is converting the stem cells into dopamine-producing-neuronal cells to replace the dead brain cells of the patient.   The three-dimensional scaffolding facilitated which allowed the neuronal cells to be injected into mice. Hopefully, this approach will eventually be ready for testing in humans; however, this is a potential glimpse to the future. To read this research paper, click here: “Generation and transplantation of reprogrammed human neurons in the brain using 3D microtopographic scaffolds” by Aaron L. Carlson et al., in Nature Communications. Published online March 17 2016 doi:10.1038/ncomms10862

“It was one of those March days when the sun shines hot and the wind blows cold: when it is summer in the light, and winter in the shade.” Charles Dickens, Great Expectations

April, 2016: Role of Mer and Axl in immune clearance of neurons in Parkinson’s.
TAM receptors are found on immune system cells and they help clear out dead cells  generated by out bodies.  Two of the TAM receptors, dubbed Mer and Axl, help immune cells called macrophages act as garbage collectors. This study asked whether or not the brain microglial cells (brain macrophages) had such activity through Mer and Axl.  Interestingly, in mice lacking Mer and Axl, neurons regenerated much more rapidly in certain areas of the brain. Furthermore, microglial expression of Axl was upregulated in the inflammatory environment in a mouse model of Parkinson’s.  These results identify TAM receptors as controllers of microglial scavenger activity and also as potential therapeutic targets for Parkinson’s.  Click here to view this article: Fourgeaud, L., et al. (2016). “TAM receptors regulate multiple features of microglial physiology.” Nature 532(7598): 240-244.

“April hath put a spirit of youth in everything. (Sonnet XCVIII)”  William Shakespeare, Shakespeare’s Sonnets

May, 2016:  Complex genetics found in the study of Parkinson’s in human brain tissue.  Genetic changes were found in Parkinson’s disease and Parkinson’s disease dementia.  A team of scientists used RNA sequencing to illuminate two phenomena linked with the onset of Parkinson’s disease: specifically, differential gene expression and alternative splicing of genes. The study describes 20 differentially expressed genes in Parkinson’s and Parkinson’s dementia, comparing these with healthy controls. Genes showing over-expression included those involved with cell movement, receptor binding, cell signaling and ion homeostasis. Under-expressed genes had an involvement with hormone signaling.  These results increase our understanding of Parkinson’s; furthermore, the complexity of their results suggest we may be able to achieve a more detailed diagnosis .  Click here to view paper: Henderson-Smith, Adrienne et al. “Next-Generation Profiling to Identify the Molecular Etiology of Parkinson Dementia.” Neurology: Genetics 2.3 (2016): e75.

“May, more than any other month of the year, wants us to feel most alive.” Fennel Hudson

June, 2016: Mutations in a gene called TMEM230 causes Parkinson’s. The role of TMEM230  was found to be in packaging the neurotransmitter dopamine in neurons.  Interestingly, TMEM230 bridges membranes in synaptic vesicles; these vesicles are storage reservoirs for neurotransmitters. Since the loss of dopamine-producing neurons defines Parkinson’s, a defect in TMEM230 implies a new link to a genetic cause of Parkinson’s.  The research team identified this mutation in Parkinson’s patients in North America and Asia. Click here to view paper: Deng, H-X, et al., “Identification of TMEM230 mutations in familial Parkinson’s disease”. Nature Genetics 48, 733–739 (2016).

“I wonder what it would be like to live in a world where it was always June.”  L.M. Montgomery

July, 2016: Improving deep brain stimulation (DBS), one patient at a time.  Instead of one-size-fits-all, these researchers are pioneering a novel strategy for fine-tuning DBS on each person’s individual physiology.  Their DBS platform, termed Phasic Burst Stimulation, has the potential to (i) enhance therapeutic efficacy, (ii) extend battery lifespan; (iii) reduce detrimental side effects, and (iv)  adjust as each person’s motor symptoms change.  This tuning-based DBS approach has real promise.  Click here to view paper: “Phasic Burst Stimulation: A Closed-Loop Approach to Tuning Deep Brain Stimulation Parameters for Parkinson’s Disease.” by A.B. Holt et al., PLOS Computational Biology, http://dx.doi.org/10.1371/journal.pcbi.100501

“My life, I realize suddenly, is July. Childhood is June, and old age is August, but here it is, July, and my life, this year, is July inside of July.” Rick Bass

August, 2016: Comparison of different movement disorders to better understand Parkinson’s.  These researchers compared multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) to Parkinson’s.  MSA and PSP are progressive disorders that also cause changes in balance and walking.  The study consisted of  functional magnetic resonance imaging (fMRI) brain scans with each person using a grip strength exercise, which showed changes in the regions of brain that control muscle movement. Parkinson’s patients showed changes in the putamen and the primary motor cortex;  MSA patients had changes in the primary motor cortex, the supplementary motor area and the superior cerebellum. PSP patients showed a change in all four areas.  Normal healthy controls had no changes. These detailed results (i) show the progression of each movement disorder and (ii) indicate that biomarkers for these specific-regions of the brain might be useful for not only monitoring disease progression but also response to therapy. Click here to view article: Burciu et al., “Functional MRI of disease progression in Parkinson disease and atypical parkinsonian syndromes.”, Burciu, Chung, Shukla, Ofori, McFarland, Okun, Vaillancourt, Neurology, 016 Aug 16;87(7):709-17. doi: 10.1212/WNL.0000000000002985

“The month of August had turned into a griddle where the days just lay there and sizzled.” Sue Monk Kidd, The Secret Life of Bees

September, 2016: Preventing falls by combining virtual reality and treadmill training.   Falling down is one of the most common and most detrimental problems in the elderly  with Parkinson’s. This research team combined treadmill use with virtual reality training. They tested a large group of older adults at high risk for falls; they found that treadmill training with virtual reality led to reduced fall rates compared to treadmill training alone.Click here to view article: Mirelman et al.,  “Addition of a non-immersive virtual reality component to treadmill training to reduce fall risk in older adults (V-TIME): a randomised controlled trial”, The Lancet, 2016 Sep 17;388(10050):1170-82. doi: 10.1016/S0140-6736(16)31325-3

“By all these lovely tokens September days are here, With summer’s best of weather And autumn’s best of cheer.”  Helen Hunt Jackson

October, 2016: Caffeine-based compounds stop alpha (a)-synuclein misfolding in a yeast model of Parkinson’s. The aggregation (misfolding) of the protein a-synuclein is thought to be a key contributing factor in neuronal cell death that leads to Parkinson’s.  The misfolded a-synuclein ultimately forms what are termed Lewy bodies, which produce much neuronal cell morbidity and mortality. Caffeine has been shown to be  somewhat protective against Parkinson’s. The study here made double-headed constructs of compounds using caffeine and nicotine and other chemicals and asked whether or not they could stop a-synuclein misfolding.  Possibly a far-fetched  idea, 2 of the caffeine-double-headed compounds worked.  These studies used a novel a-synuclein-fluorescent-green substance expressed in yeast.  Expression of the green-a-synuclein misfolded and killed the yeast; however, in the presence of the caffeine-adducts, the green-a-synuclein folded properly and the yeast stayed alive.  Such cool science.  To read this paper, click here) “Novel dimer compounds that bind α-synuclein can rescue cell growth in a yeast model overexpressing α-synuclein. a possible prevention strategy for Parkinson’s disease”, Jeremy Lee et al., ACS Chem Neurosci. Epub 2016 Oct 7. 2016 Dec 21;7(12):1671-1680. doi: 10.1021/acschemneuro.6b00209.

“Autumn is my favourite season of all. It is a transitory period that allows the earth to rest before it sees the harshness of winter and hears the promise of spring.”  Kamand Kojouri

November, 2016: PINK1 gene mutation linked to early onset of Parkinson’s.  A single mutation in the PTEN-induced putative kinase 1 (PINK1) gene has been found to promote  the development of early-onset Parkinson’s. There is growing evidence that PINK1 collaborates with the protein named PARKIN; together they help regulate neuronal cell mitochondria. This interaction to regulate mitochondria (the cell’s power plant) by  PINK1 and PARKIN is important because many brain disorders are known to have issues with energy production (mitochondria) besides Parkinson’s. Click here to view paper: Puschmann, A., et al. Heterozygous PINK1 p.G411S increases risk of Parkinson’s disease via a dominant-negative mechanism. Brain 2016; 140 (1): 98-117. doi: 10.1093/brain/aww261.

“October extinguished itself in a rush of howling winds and driving rain and November arrived, cold as frozen iron, with hard frosts every morning and icy drafts that bit at exposed hands and faces.”  J.K. Rowling, Harry Potter and the Order of the Phoenix

December, 2016:  President Obama signed the 21st Century Cures Act. Not a paper but a National Institute of Health (NIH) federally-supported research initiative. The Cures Act is focused on  cancer, brain disease, drug addiction and other diseases/processes for the next  decade. The 21st Century Cures Act contains $4.8 billion in new NIH (National Institutes of Health) funds, including the BRAIN Initiative for the comprehensive mapping of  the brain.  It is anticipated that we will achieve an even better understanding of Parkinson’s than we have today.  Recently, a commentary about the Cures Act from the viewpoint of the NIH was published in the New England Journal of Medicine. Click here to read this article: Hudson, K. L. and F. S. Collins (2017). “The 21st Century Cures Act — A View from the NIH.” New England Journal of Medicine 376(2): 111-113.

“December’s wintery breath is already clouding the pond, frosting the pane, obscuring summer’s memory…” John Geddes

“I like the scientific spirit—the holding off, the being sure but not too sure, the willingness to surrender ideas when the evidence is against them: this is ultimately fine—it always keeps the way beyond open—always gives life, thought, affection, the whole man, a chance to try over again after a mistake—after a wrong guess.”  Walt Whitman, Walt Whitman’s Camden Conversations

Useful Parkinson’s disease News/Health Information/Reference Sites (click on links below):
Google Scholar- Parkinson’s disease
Parkinson’s News Today Weekly Digest
Medical News Today (MNT)
Science News- Mind & Brain News
Harvard Medical School- Harvard Healthbeat
The Science of Parkinson’s disease
STAT
NY Times- Well
Neurology Advisor

Cover photo credit: winter smoky mts- http://holicoffee.com/wp-content/uploads/2015/05/great-smoky-mountains-national-park-usa-extreme-out-door-hiking-trail-adventure-37.jpg

PD word cloud- http://us.123rf.com/450wm/lculig/lculig1612/lculig161200292/66735623-parkinson-disease-word-cloud.jpg?ver=6

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Part 1: Journey to Parkinson’s and Barium Swallow

“It does not do to dwell on dreams and forget to live.” J.K. Rowling, Harry Potter and the Sorcerer’s Stone

“May you live every day of your life.” Jonathan Swift

 Introduction: Along the way to the diagnosis of Parkinson’s, you may have to undergo several different kinds of tests to help your physician(s) learn what actually is going on with your physiology and neurological network.  Remember there is neither a blood test nor a genetic marker evaluation to provide a diagnosis of Parkinson’s. Therefore, the clinical exams I will describe are sometimes done to exclude other disorders and to further implicate Parkinson’s.  My Neurologist says the most helpful thing is the actual patient interview (History and Physical) since most people with Parkinson’s have a characteristic set of signs and symptoms.

These posts (a series of 5 procedures) are purely descriptive/informational but they are important to describe because they can be kind of intimidating and nerve-racking  to undergo (just in case any of these tests are suggested by your physician team).  Let me be clear, I am not recommending any of these procedures for you (I’m a basic scientist not a physician). Interestingly, my Neurologist was involved only in the MRI and sleep study, which were done after my diagnosis of Parkinson’s. The other procedures were done before my diagnosis as we (another group of very talented physicians) were trying to sort out what was wrong. These are the procedures:
Part 1 describes the Barium Swallow test;
Part 2 gives an overview of Magnetic Resonance Imaging (MRI);
Part 3 highlights Polysomnography, which is a sleep study;
Part 4 presents Electromyography (EMG), which measures nerve/muscle interactions;
Part 5 characterizes Transradial Cardiac Catheterization and Angiography.

What causes someone to have difficulty in swallowing (dysphagia)? Dysphagia is the medical term used to describe someone with difficulty or discomfort from swallowing;  it is harder or takes longer to get food, liquid or pills from your mouth to your stomach. Dysphagia usually means something is not working properly in your mouth, pharynx or esophagus. Dysphagia typically occurs in older adults, and in people with brain or nerve injuries or disease.  There are two broad pathological categories  that cause dysphagia: disorders that affect the nerves and muscles of the throat and esophagus; and disorders that interfere/ block the throat and esophagus. WebMD has a very nice overview of the many causes of dysphagia (please click here).

“I may not have gone where I intended to go, but I think I have ended up where I needed to be.” Douglas Adams, The Long Dark Tea-Time of the Soul

What is a barium swallow study? How does a barium swallow study work?  Barium swallow remains the primary clinical evaluation of dysphagia.  Like the more  familiar  substance calcium, barium is also an alkaline earth metal  with a +2 charge.  When the compound barium sulfate is dissolved in water, it forms a thick chalky paste that absorbs X-rays, which is the basis of the barium swallow study. A barium swallow uses X-rays (radiographic) to examine the pharynx (back of mouth and throat) and the esophagus (a hollow tube that connects the back of the mouth to the stomach). Barium coats the lining of the pharynx and esophagus to make them visible when exposed to X-rays (electromagnetic energy that is used to visualize various internal organs). The combination of barium/ X-ray gives the radiologist a ‘movie’ (Fluoroscopy) to watch the movement of barium through the upper gastrointestinal tract.

BariumSwallow
The left panel above shows the orientation of the pharynx and esophagus between the back of the mouth and stomach, respectively; and in the middle and right panels show the result of a normal barium swallow study in a static X-ray.

For the procedure, you will be both horizontal and vertical on an imaging platform with the other body parts shielded and protected from the X-rays. You will be asked to drink a barium solution with the consistency of a milkshake. Barium actually has very little flavor. Additionally, I was given barium pills to simulate pill ingestion. Furthermore, I was also given barium mixed into applesauce and barium coated on top of graham crackers to simulate different types of textured food while you chew and swallow.  The coolest thing is you actually get to see the results in real time as you  swallow the various forms of barium. Besides the radiology people, I also had a speech pathologist present who specialized in  dysphagia.   The only difficulty in dealing with the barium swallow study was the constipation that occurred from ingestion of barium. For a more comprehensive overview of the barium swallow study (please click here) and see references cited at the bottom.

330px-Normal_barium_swallow_animation-1
The image above is a barium (solution) swallow study and the resulting x-ray ‘movie’.

“It may be unfair, but what happens in a few days, sometimes even a single day, can change the course of a whole lifetime…” Khaled Hosseini ,The Kite Runner

What is the relationship of dysphagia to Parkinson’s?  One of the earliest presenting features of my Parkinson’s was a swallowing defect, which occurred several years before my diagnosis. Interestingly, dysphagia can occur at any stage of Parkinson’s. Signs and symptoms  of a swallowing problem go from mild to severe and  typically present as follows: coughing/throat clearing  while eating/drinking; trouble swallowing certain foods or liquids; and  having a feeling  that food is getting stuck  in the back of your throat. Anyone with a swallowing defect clearly needs to be seen by a speech pathologist and your neurologist,  which would likely include a barium swallow study.

“Life is like riding a bicycle. To keep your balance, you must keep moving.” Albert Einstein

Useful reference material: there is a lot of material on the Internet to read regarding dysphagia,  barium swallow, and  dysphagia in Parkinson’s. However,  I found the following to be very useful in learning about swallowing defects in Parkinson’s:
-Barium Swallow  (from the University of Rochester Medical Center describing all the aspects of barium swallow, to view it click here);
-Dysphagia (from WebMD with a nice overview of dysphagia, please click here).
-Upper Gastrointestinal Examination [from the Lahey Clinic in Boston with a very nice overview (text/visual) of the upper GI exam, to view it click here];
Parkinson Disease: Speech and Swallowing (from the National Parkinson Foundation, an informative and well-written pamphlet);
-Swallowing and Parkinson’s Disease  (from the U.S. Veterans Administration, an  interesting presentation describing dysphagia in  Parkinson’s, to view it click here).

“I wanted a perfect ending. Now I’ve learned, the hard way, that some poems don’t rhyme, and some stories don’t have a clear beginning, middle, and end. Life is about not knowing, having to change, taking the moment and making the best of it, without knowing what’s going to happen next. Delicious Ambiguity.” Gilda Radner

Cover photo credit: http://www.pachd.com/free-images/napa/napa-07.jpg
Pharynx and esophagus d: https://sites.google.com/a/mtlstudents.net/wallace-davis-digestive/_/rsrc/1429639718932/home/pharynx-and-esophagus/normal-pharynx-esophagus-anatomy-lg-bdy.jpg?height=320&width=200
Normal barium swallow X-ray image: http://images.radiopaedia.org/images/501264/edcd492f95768c4dcd045283fe7845.jpeg
Barium swallow gif-movie: By Normaler_Schluck-00.jpg (and others): Hellerhoffderivative work: Anka Friedrich (talk) – 34 files:Normaler_Schluck-00.jpg[…]Normaler_Schluck-33.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15333554

 

 

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Importance of Model Systems in Parkinson’s Research

“Science is organized knowledge. Wisdom is organized life.” Will Duran

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…’” Isaac Asimov

Introduction:  The goal of this post is to highlight several experimental model systems that have effectively been used in Parkinson’s research.  We  have gained tremendous knowledge about all aspects of Parkinson’s from the use of model systems (Please note there are many publications that could have been included here by many different outstanding scientists; this is just a sampling of the strong science in the field of Parkinson’s disease).

The alpha-synuclein story in Parkinson’s: Alpha-synuclein is  a protein found in the brain that form aggregates (clumps of protein) called Lewy bodies.   Lewy bodies accumulate inside the substantia nigra region of the brain and they are toxic to the neurons and they no longer synthesize dopamine.   Part of the toxicity of alpha-synuclein-forming Lewy bodies is linked to mitochondria inhibition,  the little energy factories found in  our cells. This is just a sampling of alpha-synuclein in Parkinson’s (here is a PubMed search: http://www.ncbi.nlm.nih.gov/pubmed/?term=alpha-synuclein+Parkinson%27s ).

“Science is the process that takes us from confusion to understanding…” Brian Greene

The need for experimental model systems:  Scientists develop and use various experimental tools to answer their research questions. The ‘strength’ of the observation is usually dependent on the ‘quality’ of the experimental model system. Described here are four of many different experimental model systems: yeast; Caenorhabditis elegans (C. elegans); human, rat or mouse neuronal cells; and the mouse (or rat). Ultimately, scientists and physicians ‘translate’ this information for use in human clinical trials, which defines the phrase “bench-to-bedside”.

PD.model.16.02..25

“I never guess. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” Sir Arthur Conan Doyle, Author of Sherlock Holmes stories

Advancing our understanding of Parkinson’s using experimental model systems: You must remember a couple of things about science and research in general. Asking and answering one question usually leads to another question that needs to be answered. Typically, the next questions are more complex as the story unfolds. It is kind of like peeling an onion, you start taking off the top layer and you keep going; the more questions you answer the more layers you have to peel. Let’s go peel some onions.

Rising yeast in biology:  In our everyday lives,  baker’s yeast is used to make bread and alcoholic beverages like beer.  Yeast are single cell organisms, but like human cells they are eukaryotic (defined as “…cells that contain a distinct membrane-bound nucleus and by the occurrence of DNA transcription inside the nucleus and protein synthesis in the cytoplasm….” http://www.thefreedictionary.com/eukaryote ). Yeast are easy to culture and they share many similarities to human cells;  furthermore, genetic manipulation is relatively easy to do in yeast and offers a powerful tool for biomedical science. [Also see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3213361/%5D

Use of yeast in Parkinson’s research Tardiff and others performed a really clever experiment, they expressed alpha-synuclein in yeast.  They found that yeast, just like human neuronal cells, got sick in the presence of excess amounts of alpha-synuclein.  They used the yeast expressing alpha-synuclein  and asked the following questions. Could a compound neutralize or reverse the alpha-synuclein-induced toxicity in yeast? Would this compound be able to restore normal function to the yeast?  They tested  ~190,000 compounds to see whether any of those would reverse the toxic effects and allow the yeast to rapidly grow again.  One lead compound evolved from this study, N-aryl benzimidazole (NAB).  NAB corrected the problem in yeast expressing alpha-synuclein. Using elegant genetics, they found that NAB activates a “trafficking” protein named Rsp5. The alpha-synuclein-induced toxicity  was inhibiting the function of Rsp5, which means that NAB reverses this effect. This sets the scene for new pathways to be explored for how Parkinson’s evolves, and presents a new strategy for exploring drugs to treat this disorder.
Tardiff DF, Jui NT, Khurana V, et al. Yeast reveal a “druggable” Rsp5/Nedd4 Network that Ameliorates α–Synuclein Toxicity in Neurons. Science (New York, NY). 2013;342(6161):979-983. doi:10.1126/science.1245321.

“Science is a way of thinking much more than it is a body of knowledge.” Carl Sagan

“Worm people” advancing science using C. elegans: C. elegans are non-parasitic soil nematodes that are free-living (…worms of the phylum Nematoda, having unsegmented cylindrical bodies often narrowing at each end, and including free-living species that are abundant in soil and water, and species that are parasites of plants and animals…” http://www.thefreedictionary.com/nematode ). C. elegans is a model organism due to its ability to be easily grown and manipulated genetically, which scientists use to advance complex biological principles.  [Also see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1855192/%5D

Use of worms in Parkinson’s research Advanced age is the greatest known risk factor for development of Parkinson’s.  Why this happens is not fully understood. Cooper and others proposed the following hypothesis: “…there are specific changes that take place during the aging process that make cells susceptible to disease-causing mutations that are well-tolerated at younger ages.” To begin to ‘test’ this hypothesis, they used genetics and C. elegans as a model system.  Worms containing mutations in the daf-2 gene live twice as long as control worms.  The researchers crossed  C. elegans models of Parkinson’s with daf-2 mutants.  Compared to the appropriate control worms, the Parkinson’s/daf-2 mutant worms had longer lifespan, protection of dopamine neurons, resistance to inflammatory stress, and decreased Lewy-body formation. This C. elegans genetics-aging study implies that slowing down the aging process is neuroprotective in Parkinson’s.
Jason F Cooper, Dylan J Dues, Katie K Spielbauer, Emily Machiela, Megan M Senchuk, and Jeremy M Van Raamsdonk. Delaying aging is neuroprotective in Parkinson’s disease: a genetic analysis in C. elegans models. npj Parkinson’s Disease (2015) 1, 15022; doi:10.1038/npjparkd.2015.22; published online 19 November 2015

“What we find changes who we become.” Peter Morville

Cells provide a cultivating environment to model tissues/organs:  Over the past several decades, many different types of cells have been grown in sterile plastic dishes; ranging from “primary” cell extracts obtained from different organs to “immortalized” cell types from various tumor types (i.e., cancer).  Cells grown in vitro (defined as “performed or taking place in a test tube, culture dish, or elsewhere outside a living organism” https://www.google.com/search?q=define+in+vitro&ie=utf-8&oe=utf-8) do not fully recapitulate the organ of origin; nonetheless, cell culture is a powerful model system to study both normal biological and abnormal pathological processes. [Also see http://www.biologyreference.com/Bl-Ce/Cell-Culture.html%5D

Use of neuronal cells in Parkinson’s research Proteins have unique three-dimensional shapes, which encode their biological activity.  Sometimes, proteins go bad and do things that are pathological like alpha-synuclein forming aggregates. Moree and others are testing a hypothesis that small molecules can be discovered that reverse such detrimental protein aggregation. They developed a novel screening technique to identify compounds that modulate protein conformation (which is way beyond the scope of this blog posting). They discovered a compound named BIOD303 as a novel conformational modulator of alpha-synuclein.Interestingly, these modulators reduced alpha-synuclein aggregation in an experimental neuronal cell model. This sort of study could (possibly one day) lead to a novel process for treating Parkinson’s by reversing alpha-synuclein aggregates.
Moree B, Yin G, Lázaro DF, et al. Small Molecules Detected by Second-Harmonic Generation Modulate the Conformation of Monomeric α-Synuclein and Reduce Its Aggregation in Cells. The Journal of Biological Chemistry. 2015;290(46):27582-27593. doi:10.1074/jbc.M114.636027.

“Science does not know its debt to imagination.” Ralph Waldo Emerson

The mouse (rat) provides a most important model system:  Our understanding of many human diseases (think cardiovascular, cancer, and yes, Parkinson’s) has been advanced using mice and rats as model systems. One reason why mice are used is the similarity of mouse and human genetics. Scientists have done amazing feats using mice including “gene knockout” where specific genes have been deleted or inactivated.  Another type of mouse genetically-derived is the “transgenic mice”, which usually express genes thought to promote human diseases.  Ultimately, a mouse (or rat) with a specific disease becomes a model or ‘stand-in’ for that same human disease or condition.  [Also see  http://emice.nci.nih.gov/aam%5D

Use of rats in Parkinson’s researchVolakakis and others studied how alpha-synuclein promotes changes in dopamine-producing neurons. They found that alpha-synuclein alters gene expression and that a transcription factor (a protein that binds to specific DNA sequences that modulates the genetic information being transcribed from DNA to messenger RNA) known as Nurr1 helps resist these effects. They found that nuclear substances that bind to Nurr1’s partner retinoid X receptor (RXR) also had a neuroprotective role. Their results clearly highlight Nurr1’s neuroprotective role against alpha-synuclein-induced changes in dopamine-producing neurons. Furthermore, their results imply that RXR ligands have therapeutic potential in Parkinson’s.
Volakakis N, Tiklova K, Decressac M, Papathanou M, Mattsson B, Gillberg L, Nobre A, Björklund A, Perlmann T. Nurr1 and Retinoid X Receptor Ligands Stimulate Ret Signaling in Dopamine Neurons and Can Alleviate α-Synuclein Disrupted Gene Expression. J Neurosci. 2015 Oct 21;35(42):14370-85. doi: 10.1523/JNEUROSCI.1155-15.2015. PMID:26490873

“Barry L. Jacobs and colleagues from the neuroscience program at Princeton University showed that when mice ran every day on an exercise wheel, they developed more brain cells and they learned faster than sedentary controls. I believe in mice.”  Bernd Heinrich

From bench-to-bedside: The four papers described here represent the tip-of-the-iceberg in Parkinson’s research. As with any basic science study, the next step, the next few years are key to developing/advancing/evaluating these questions and getting answers. I am optimistic that new compounds, new treatment strategies, and further understanding of Parkinson’s are coming in the near future. It just will take time, so we must remain patient while all of their research endeavors progress.

“From the standpoint of daily life, however, there is one thing we do know: that we are here for the sake of each other – above all for those upon whose smile and well-being our own happiness depends, and also for the countless unknown souls with whose fate we are connected by a bond of sympathy. Many times a day I realize how much my own outer and inner life is built upon the labors of my fellow men, both living and dead, and how earnestly I must exert myself in order to give in return as much as I have received.” Albert Einstein

Cover photo credit: http://www.boredpanda.com/beautiful-winter-photos/

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Neuroprotection by Modified-Macrophages in a Parkinson’s Model System

“Somewhere, something incredible is waiting to be known.” Carl Sagan

“You never change things by fighting the existing reality.  To change something, build a new model that makes the existing model obsolete.” R. Buckminster Fuller

Précis: Scientists at the University of North Carolina at Chapel Hill are using an innovative approach to treat Parkinson’s in a model animal system (I realize this is my University, but it’s still very cool science). Dr. Elena Batrakova’s research is focused on engineering macrophages (a key host defense cell) for delivery to and therapy in the brain.  This “Trojan Horse” therapeutic system has been used for treating Parkinson’s in an animal model (go here: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106867).

What is a Trojan Horse therapeutic system?  From Greek mythology:The Trojan Horse is a tale from the Trojan War about the subterfuge that the Greeks used to enter the city of Troy and win the war. In the canonical version, after a fruitless 10-year siege, the Greeks constructed a huge wooden horse, and hid a select force of men inside.” (https://en.wikipedia.org/wiki/Trojan_Horse).  From  modern neuroscience and molecular engineering: The Trojan Horse therapeutic system is to use a naturally occurring cell (macrophage) that fools the body (to get into and past the blood brain barrier) into accepting the cell as self. After being accepted as self, it allows the material housed inside the macrophage to be released directly at the site of injury (mid-brain region called substantia nigra that has dopamine producing cells). The drawing below illustrates the science of this study and the depiction of the Trojan Horse.

Macrophages+Parkinsons.160208

“Everything is theoretically impossible, until it is done.” Robert A. Heinlein

What are macrophages (in this study they are the Trojan horse)? Bone marrow makes many different cell types including red blood cells, white blood cells (WBC), and platelets. Macrophages are derived from the WBC named monocyte. Monocytes released from the bone marrow circulate in the bloodstream for a couple of days and leave and go to the various organs and tissues where they mature and become macrophages.  Macrophages are incredibly versatile and important cells in our host defense system; including a role as a sentinel, a role as a  General in a bunker giving out orders to all the other soldiers, and even a role functioning as a garbage collector. Let me explain. Macrophages live in our tissues and they stand guard ready to attack invading microorganisms.  Macrophages generate many different substances (growth factors and  cytokines)  that recruit and activate WBC’s both to enhance the attack against invading microorganisms  and to initiate the immune system.  Macrophages also help out by cleanup debris and cellular waste products. Macrophages can be activated when  exposed to different kinds of inflammatory cytokines and they become what are called M1 and M2 macrophages.  M1 macrophages have a role being pro-inflammatory while M2 macrophages have a role being regenerative.

“The good thing about science is that it’s true whether or not you believe in it.” Neil deGrasse Tyson

What is GDNF (in this study it is the Greek soldiers)? GDNF  stands for glial cell-line derived neurotrophic factor  (neurotrophic substances regulate the growth, survival, and differentiation of nerve cells/nervous tissue).  There is evidence in the scientific literature of the positive impact of neurotrophic factors in experimental treatment of Parkinson’s. The idea behind using GDNF is to promote survival of dopamine producing neurons and also to reduce inflammation in the mid-brain area. One of the major obstacles to this research area in general has been delivering the neurotrophic factor through the blood brain barrier and to the damaged tissue. The study here gets around this by using the macrophage as the carrier to deliver GDNF, the neurotrophic factor, directly to the brain.

“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.” Marie Curie

Is this research similar to regenerative medicine?  Ultimately, if this science translates from bench-to-bedside, it satisfies elements of what is called regenerative medicine.  By definition, “regenerative medicine is a branch of translational research in tissue engineering and molecular biology which deals with the ‘process of replacing, engineering or regenerating human cells, tissues or organs to restore or establish normal function.'” (https://www.google.com/search?q=personalized+medicine&ie=utf-8&oe=utf-8#q=regenerative+medicine+definition).  The approach used in this study was first, to use the macrophage as the protective cell carrier and as the decoy in the Trojan horse model. And second, to express GDNF in the macrophage and have the macrophages deliver the neurotrophic factor directly to the brain. This idea is partially based on the hypothesis that macrophages would migrate toward areas of inflammation; there is substantial evidence linking inflammation in the mid-brain region to someone with Parkinson’s.

“Wonder is the seed of knowledge” Francis Bacon

 Was there good news using GDNF-expressing macrophages in the experimental mouse model of Parkinson’s?   There were several notable positive results from the study, including: 1)  macrophages were able to be transfected with GDNF; 2)  macrophages were activated to the M2 regenerative state; 3) injecting GDNF-expressing macrophages into the Parkinson’s disease mouse showed significant  improvement in both neuroinflammation and  neurodegeneration; 4) behavioral studies confirmed the neuroprotective effect in the mouse model; and 5) these results indicate successful   delivery of GDNF by macrophages, release of GDNF into the affected area, and transfer of the neurotrophic factor to the appropriate targeted neurons.

“The scientist is not a person who gives the right answers, he’s one who asks the right questions.” Claude Lévi-Strauss

Of ‘Mice and Men’, what do the results mean for the future treatment of Parkinson’s?  The results of this paper are both elegant and straightforward.  Their overall goal is to use cell-mediated delivery of therapeutic substances that either stop or slow progression of Parkinson’s. Doing this successfully in a mouse model is one thing; however, getting it translated into a human study is another. We must remain positive that scientists of this caliber continue to get their research funded, continue to train scientists in the neurodegenerative field, and continue to publish their results.  We must remain persistent in managing our own disorder because there are several important studies going on right now; and some of them could reverse and/or slow down the progression of Parkinson’s.  Is this really possible? Time will tell whether this study translates from mice to men.  Finally, I am hopeful that in the near-future a strategy will emerge to slow/halt the progression of Parkinson’s; allowing our return to normalcy.

“The important thing is to not stop questioning. Curiosity has its own reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day. Albert Einstein —”Old Man’s Advice to Youth: ‘Never Lose a Holy Curiosity.'” LIFE Magazine (2 May 1955) p. 64”

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Science of Advanced Age as a Risk Factor for Parkinson’s

“Spring passes and one remembers one’s innocence.
Summer passes and one remembers one’s exuberance.
Autumn passes and one remembers one’s reverence.
Winter passes and one remembers one’s perseverance.”
Yoko Ono

“Embrace aging.” Mitch Albom, Tuesdays with Morrie

Précis: The great majority of individuals with Parkinson’s reveal no genetic mutations, no past history of head injury, no prior exposure to pesticides/toxins, or any family history of the disorder.  Public health studies have consistently shown that advanced age is an adverse risk factor for developing Parkinson’s. The average age of Parkinson’s onset is ~60 years of age. Presented here is a brief overview about why advanced age is a major risk factor for Parkinson’s.

Parkinson’s and advanced age as a risk factor: Parkinson’s is a neurodegenerative disorder that affects movement. It starts slowly, usually a small tremor or stiffness in a hand. With time, Parkinson’s progresses; typically characterized by motor symptoms such as slowness of movement (bradykinesia) with rigidity, resting tremor (Parkinsonian tremor), balance and walking problems, and difficulty swallowing and talking. Parkinson’s has several non-motor symptoms including anxiety, depression, and insomnia (just to mention a few).

Following Alzheimer’s, Parkinson’s is the second most common neurodegenerative disorder affecting ~0.3% of the developed world population. Interestingly, the incidence of Parkinson’s increases to 3% for persons >65 years old, which strongly indicates that advanced age is a major risk factor for this disorder.

Aging can promote several detrimental events that damage the dopamine-producing neurons in the substantia nigra.  These pathological events accumulate and weakens the ability of these neurons to respond to further insults, which ultimately leads to Parkinson’s (see below).

The left-side of the composite picture below could be entitled “40 years of Frank (in my 20’s, 30’s, 50’s and 60’s).”  The title of the right-side of the composite picture could be “Somehow the neurons in my substantia nigra (top right) are making very little dopamine (chemical structure bottom right); thus, I have Parkinson’s.”

Frank+40yrs“As long as I am breathing, in my eyes, I am just beginning.” Criss Jami

Age of the U.S. population: Andy Rooney once said “It’s paradoxical that the idea of living a long life appeals to everyone, but the idea of getting old doesn’t appeal to anyone.”  As the table below shows, by each successive decade of life, females outlive males. However, between 2000 and 2010, the U.S. male population grew at a slightly faster rate than the female population. By contrast, mortality rates in older men differ from older women, where the census results showed that women tend to live longer than men.  A further breakdown shows the 65 to 69 year old age group grew by 30%; this age group represents the leading edge of the Baby Boomers who started turning 65 in 2011 (The Baby Boom includes people born from mid-1946 to 1964). We are living longer; when coupled with advanced age as a risk factor for Parkinson’s, this implies an increasing burden on health care systems to deal with this disorder.

Age.USA.150930
“Wisdom comes with winters.” Oscar Wilde

Science behind advanced age as an adverse risk factor for Parkinson’s:  Pat Benatar said this about aging, “I’ve enjoyed every age I’ve been, and each has had its own individual merit. Every laugh line, every scar, is a badge I wear to show I’ve been present, the inner rings of my personal tree trunk that I display proudly for all to see. Nowadays, I don’t want a “perfect” face and body; I want to wear the life I’ve lived.”  Advanced age contributes to many different diseases whether from a loss of organ function with time, diminished immune surveillance capacity, or the inability to remove naturally-accumulating toxic substances by the host defense mechanisms (just to describe a few of many possible outcomes of advancing age).

In evaluating a large group of elderly people without Parkinson’s (750 individuals with an average age of 88.5 years), it was noted that ~1/3 showed mild to severe substantia nigra neuronal cell loss. Thus, natural advanced aging results in some loss to the dopamine-producing substantia nigra mid-brain region. But what shifts the balance that leads to Parkinson’s in some individuals?  Reeve et al. (2014), in an outstanding article, reviewed the science behind why advancing age is the biggest risk factor for Parkinson’s.  They suggest three processes occur in the substantia nigra that ultimately leads to Parkinson’s: (1) detrimental changes to the microenvironment; (2) dysfunction of the subcellular organelles called mitochondria; and (3) disruption in the process of protein degradation (the drawing below highlights these processes).

Aging.SN(1) Detrimental changes to the substantia nigra microenvironment:  As an analogy, over time, with extended use and re-use, your laptop slows down and ultimately begins little processor-derived-hiccups-of-dysfunction.  As we age, some changes occur in the dopamine-producing neurons of the substantia nigra; these include increased oxidative stress, changes in calcium-neuron properties, modification of iron-neuron interactions, and accumulation of the pigment called neuromelanin.  Processing of dopamine in the substantia nigra generates detrimental oxidative stress; which is made worse due to an age-related reduction of a protein named the dopamine transporter (DAT). The DAT escorts dopamine from neuron-to-neuron to reduce oxidative stress. Calcium helps maintain dopamine levels; and sustained transport of calcium into the cell is detrimental to the energy-producing organelle, the mitochondria.  Iron is an essential element; however with age, iron accumulates to contribute to the oxidative stress. Neuromelanin is responsible for the color of the substantia nigra.  Evidently, neuromelanin accumulates with age; in contrast to the other factors mentioned above, neuromelanin may be neuroprotective.

(2) Dysfunction of the subcellular organelles called mitochondria:  As an analogy, over time, you charge the battery of many devices like your cell phone, laptop/tablet, toothbrush, and beard trimmer; eventually no matter what you do, slowly but surely these devices lose their charge.  Likewise, mitochondria are subcellular power factories that can become dysfunctional (and lose energy) with advancing age. The mitochondrial respiratory system (electron transport) is a major cellular energy producer; and it consists of five protein complexes named respiratory complexes I–V. Several mitochondria electron transport complexes are modified/inhibited with age, leading to a loss of mitochondria-derived energy. Inhibiting complex I (reduced NADH dehydrogenase–ubiquinone oxidoreductase) causes Parkinsonian-like symptoms; furthermore loss of complex IV (cytochrome c oxidase) promotes a respiratory deficiency. This leads to the reduction of energy production (ATP molecules), which would negatively impact “neuronal excitability” (engaging/activating the neuron). Linked to this energy drain is mutation of mitochondria DNA, causing further detriment to these dopamine-producing neurons. These mutations ultimately reduce mitochondria function and activity, which promotes the accumulation of mis-folded proteins (a very bad thing). A key disease-causing feature of Parkinson’s is the build-up and denaturation of the protein named alpha-synuclein (think of the changes of frying an egg, which goes from clear to cloudy-opaque as the heat cooks and denatures the egg proteins). Accumulation of alpha-synuclein protein aggregates advances further mitochondria impairment.

(3) Disruption in the process of protein degradation:  As an analogy, shaving with a new razor blade leads to complete cutting-off of the hair; however, over time, as the razor blade dulls you end-up with more and more uncut hair. Similarly, we use enzymes called proteases and they are somewhat like a razor blade; their goal is to cut-up (digest) proteins.  Proteases are used in many different biological settings (e.g., digestion of food, clotting of blood); in the substantia nigra, proteases help eliminate protein debris as a means of self-renewal of the neurons.  There are two types of protease processes that cut and remove accumulating damaged proteins (like alpha-synuclein aggregates); they are named the ubiquitin proteasome system and autophagy.  Due to their complex biology, neither the ubiquitin proteasome system nor autophagy will be further described here; suffice it to say that if both protease systems are diminished this will further impair mitochondria.  These checks-and-balances are lost with advanced aging, which leads to a concert of adverse events where an individual could develop Parkinson’s.

“There is a fountain of youth: it is your mind, your talents, the creativity you bring to your life and the lives of people you love. When you learn to tap this source, you will truly have defeated age.” Sophia Loren

A symphony combining (1) + (2) + (3) from above + advancing age = risk of developing Parkinson’s: The natural-biology of dopamine-producing neurons leads to declining function with advanced aging. The detrimental process of reactive oxygen species initiates a symphony of badness that leads to neuronal cell dysfunction/death. The larghetto first movement leads to the reduction of the DAT, accumulation of neuromelanin, increased iron deposits, and disruption of calcium transport. The next movement is fortissimo with mutation of mitochondria DNA, inhibition of complex I and complex IV to reduce both ATP levels and neuronal excitability; these events lead to the acquisition of other mitochondria defects. The cadenza results in the beginning phase of aggregating alpha-synuclein, which contributes to substantia nigra dysfunction.  In the final movement of our symphony, we reach a crescendo where toxic levels of aggregating alpha-synuclein accumulate that cannot be cut/removed by the protein degradation pathways. The symphony ends with substantial stress to the dopamine-producing neurons in the substantia nigra to eventually promote neuronal cell death, which results in Parkinson’s.  With advancing age, most individuals will stop at the end of the first movement (microenvironment changes to substantia nigra); while others will complete the entire symphony over-and-over again to develop Parkinson’s.

“Age has no reality except in the physical world. The essence of a human being is resistant to the passage of time. Our inner lives are eternal, which is to say that our spirits remain as youthful and vigorous as when we were in full bloom. Think of love as a state of grace, not the means to anything, but the alpha and omega. An end in itself.” Gabriel García Márquez, Love in the Time of Cholera

References Cited:
Reeve, A., et al, Ageing and Parkinson’s disease: Why is advancing age the biggest risk factor?, Ageing Research Reviews, Volume 14, March 2014, Pages 19-30, http://dx.doi.org/10.1016/j.arr.2014.01.004.

Abdullah, R., et al., Parkinson’s disease and age: The obvious but largely unexplored link, Experimental Gerontology, Volume 68, August 2015, Pages 33-38, http://dx.doi.org/10.1016/j.exger.2014.09.014.

Petralia, R.S. , et al., Communication breakdown: The impact of ageing on synapse structure, Ageing Research Reviews, Volume 14, March 2014, Pages 31-42, http://dx.doi.org/10.1016/j.arr.2014.01.003.

Mhyre, Timothy R. et al. Parkinson’s Disease. Sub-cellular biochemistry 65 (2012): 389–455. PMC. Web. 9 Nov. 2015.  doi:  10.1007/978-94-007-5416-4_16  PMCID: PMC4372387