Immature Neuron Proliferation in

Correlation to Cognition in Aging Vervet Monkeys

Julian Roby Wiley CollegeMarshall, TX

Leadership Alliance SR-EIP Howard University Washington, DC

Statement of the

Problem Alzheimer’s disease is the sixth leading cause of death in the US (5th in those 65 and older) according to the CDC.

Alzheimer’s is the most common neurodegenerative disorder leading to dementia.

Some changes associated with neurodegenerative disease include reduction in processing speed and working memory.

Statement of Problem

Alzheimer’s signs can go unnoticed for years

Alzheimer’s signs can also become noticeable immediately

There is currently no cure for Alzheimer’s disease

Alzheimer’s worsens as it progresses, ultimately leading to death

What has been discovered!

Aging brain studies have been preformed on genetically engineered mice

Mice are showing beta amyloid plaques (but not neurofibrillary tangles from tau)

Vervet Monkey Old World Monkey

Cercopithecidae family & Native to Africa

Omnivores

Disease Free

Characteristics similar to humans

Hypertension Anxiety

IntroductionFast deteriorating population are the monkeys that had normal cognitive abilities and then had a sudden extreme decline in cognition. Slow deteriorating population are the monkeys with normal cognitive abilities then, slowly began to decline over time and lose cognitive abilities. An adolescent monkey was used to show normal immature neuron population.

The monkeys are group housed in their naturalistic environment at the Behavioral Science Foundation in St. Kitts.

Fed every day, protein in the morning, fruits and vegetables through out the day.

After the age of 15, their cognitive abilities are tested using a Can-tab touch screen memory test every six months.

Methodology

ImmunohistochemistryDouble Cortin

StainingThe brain tissue was washed in 10 mL mixture of 10% hydrogen peroxide (1 mL), 90% 2X deionized water (9 mL), three times for five minutes each time.

Then I washed the tissue for 30 minutes in a solution of: 3 mL of NHS (normal horse serum) with 97 mL of 1X PBS

Then I incubated the tissue overnight at room temperature in a 30 mL mixture of .25% DCX Ab (.075 mL), 3% NHS (.001 mL) and 1X PBS (29.924 mL).

The Next day I washed the tissue in 1X PBS (phosphate buffer solution) three times at five minutes each.

Then I incubated the tissue in a 30 mL mixture containing .25% biotinylated horse anti-goat IgG (.075 mL), and 1X PBS (29.925 mL). Then I incubated the tissue in a 10 mL of 1X PBS with 2 drops of A, and 2 drops of B for an hour. Then I washed the tissue in 1X PBS three times for five minutes each. Then I incubated the tissue in 45 mL of DAB (45 mL of deionized water, three gold tablets and two silver tablets) for seven minutes. Finally I washed the tissue in 1X PBS three times for five minutes each wash, and refrigerate in PBS overnight.

Hypothesis

Immature neuron population would be directly correlated with cognitive functioning in aging Vervet brains.

ResultsAmygdala

ResultsDentate Gyrus

ConclusionOverall decrease in immature neurons in fast deteriorating population

Slow deteriorating population has normal immature neuron population in amygdala, while a decrease in dentate gyrus

We know that in Vervet monkeys that the immature neuron population is a direct correlation with cognition.

We can use the primate model to directly correlate with neuronal growth.

LimitationsWhen doing the immunohistochemistry for the control monkey there was a solution error, and the immature neurons were not visible. So the immunohistochemistry was done on the tissue of an adolescent monkey to replace the control model for the immature neuron population.

Only 3 of the 34 monkeys were used in this study, because of time restrictions.

What should you take away!

As in the Vervet monkeys, you would see the similar immature neuron growth in humans.

We can use the Vervet monkey brain as a model for future studies in how the brain ages.

This study is a potential model for better understanding Alzheimer’s disease.

This research provides the foundation for the upcoming year, where students will continue experimenting.

Bibliography Artegiani, Benedetta, and Federico Calegari. "Age Related Cognitive Decline: Can Neural Stem Cells Help Us?" Aging 4.3 (2012): 176-86. Print.

Cramer, Steven C., Mriganka Sur, Bruce H. Dobkin, Charles O'Brien, Terence D. Sanger, John Q. Trojanowski, Judith M. Rumsey, Romano Hicks, Judy Cameron, Daofen Chen, Wen G. Chen, Leonardo G. Cohen, Christopher DeCharms, Charles J. Duffy, Guinevere F. Eden, Eberhard E. Fetz, Rosemarie Filart, Michelle Freund, Steven J. Grant, Suzanne Haber, Peter W. Kalivas, Bryan Kolb, Arthur Kramer, Minda Lynch, Helen S. Mayberg, Patrick S. McQuillen, Ralph Nitkin, Alvaro Pascual-Leone, Patricia Reuter-Lorenz, Nicholas Schiff, Anu Sharma, Lana Shekim, Michael Stryker, Edith V. Sullivan, and Sophia Vinogradov. "Harnessing Neuroplasticity for Clinical Applications." Brain 134 (2011): 1591-609. Print.

Lemere, Cynthia. "Alzheimer’s Disease A Vaccine Reduces Central Nervous System A Levels in a Non-Human Primate, the Caribbean Vervet." American Journal of Pathology 165.1 (2004): 283-97. Print.

Muddanna, Rao S. "Efficacy of Doublecortin as a Marker to Analyse the Absolute Number and Dendritic Growth of Newly Generated Neurons in the Adult Dentate Gyrus." European Journal Of Neuroscience 19 (2004): 234-46. Print.

Oules, Benedicte, Delores Del Prete, Babara Greco, Xuexin Zhang, Inger Lauritzen, Jean Servalle, Sebastien Moreno, Patrizia Paterlini-Brechot, Mohamed Trebak, Frederic Checler, Fablo Benfenati, and Mounia Chamia. "Ryanodine Receptors Blockade Reduces Amyloid-beta Load and Memory Impairments in Tg2576 Mouse Model of Alzheimer Disease." National Institute of Health Author Manuscript (2013): 1-34. Print.

Rola, Radoslaw, Jacob Raber, Angela Rizk, Shinji Otsuka, Scott R. VandenBerg, Duncan R. Morhardt, and John R. Fike. "Radiation-induced Impairment of Hippocampal Neurogenesis Is Associated with Cognitive Deficits in Young Mice." Experimental Neurology 188.2 (2004): 316-30. Print.

Acknowledgements

Dr. Mark Burke, PhD, Assistant Professor, Department of Physiology & Biophysics, College of Medicine Howard University – Faculty Mentor

Heather Carryl, Graduate Assistant, Department of Physiology & Biophysics, College of Medicine, Howard University

Dr. Walter Shumate, Faculty Advisor, Department of Natural Sciences, Wiley College , Marshall, TX

S. Tyrone Barksdale, Assistant to the Provost, Office of the Provost and Chief Academic Officer, Howard University, Summer Program Coordinator