Scientific Publications by FDA Staff

J Alzheimers Dis 2017;59(1):57-66

Neurodegenerative markers are increased in postmortem BA21 tissue from African Americans with Alzheimer's disease.

Ferguson SA, Panos JJ, Sloper D, Varma V

BACKGROUND: Alzheimer's disease (AD) presents with an earlier onset age and increased symptom severity in African Americans and Hispanics. OBJECTIVE: Although the prevalence of plaques and tangles may not exhibit ethnicity-related differences, levels of neurodegenerative proteins have not been described. METHODS: Here, levels of five proteins (i.e., S100B, sRAGE, GDNF, Abeta40, and Abeta42) and the Abeta42/Abeta40 ratio were measured in postmortem samples of the middle temporal gyrus (BA21) from age-matched African Americans and Caucasians with AD (n = 6/gender/ethnicity). RESULTS: S100B levels were increased 17% in African Americans (p < 0.003) while sRAGE was mildly decreased (p < 0.09). Abeta42 levels were increased 121% in African Americans (p < 0.02), leading to a 493% increase in the Abeta42/Abeta40 ratio (p < 0.002). Analysis of GDNF levels did not indicate any significant effects. There were no significant effects of gender and no significant ethnicity with gender interactions on any analyte. Effect size calculations indicated "medium" to "very large" effects. CONCLUSION: S100B is typically elevated in AD cases; however, the increased levels in African Americans here may be indicative of increased severity in specific populations. Increased Abeta42/Abeta40 ratios in the current study are compatible with increased disease severity and might indicate increased AD pathogenesis in African Americans. Overall, these results are compatible with a hypothesis of increased neuroinflammation in African Americans with AD.