Abstract:
Within South Asia, Sri Lanka represents fastest aging with 13% of the population was aged over 60’s in 2011,
whereas in India it was 8%. Majority of the Sri Lankan population based genetic studies have confirmed their origin on
Indian mainland. As there were inadequate data on aging cytoskeletal pathologies of these two nations with their close genetic
affiliations, we performed a comparison on their elderly. Autopsy brain samples of 50 individuals from Colombo,
Sri Lanka (mean age 72.1yrs ± 7.8, mean ± S.D.) and 42 individuals from Bangalore, India (mean age 65.9yrs ± 9.3) were
screened for neurodegenerative pathologies using immunohistochemical techniques. A total of 79 cases with incomplete
clinical history (Colombo- 47 and Bangalore- 32) were subjected to statistical analysis and 13 cases, clinically diagnosed
with dementia and/or Parkinsonism disorders were excluded. As per National Institute on Aging- Alzheimer’s Association
guidelines, between Colombo and Bangalore samples, Alzheimer’s disease neuropathologic change for intermediate/ high
level was 4.25% vs. 3.12% and low level was 19.15% vs. 15.62% respectively. Pathologies associated with Parkinsonism
including brainstem predominant Lewy bodies- 6.4% and probable progressive supra nuclear palsy- 2.13% were found
solely in Colombo samples. Alzheimer related pathologies were not different among elders, however, in Colombo males,
neurofibrillary tangle grade was significantly higher in the region of hippocampus (odds ratio = 1.46, 95% confidence interval
= 0.07-0.7) and at risk in midbrain substantia nigra (p = 0.075). Other age-related pathologies including spongiform
changes (p < 0.05) and hippocampus cell loss in dentate gyrus region (p < 0.05) were also identified prominently in Colombo
samples. Taken together, aging cytoskeletal pathologies are comparatively higher in elderly Sri Lankans and this
might be due to their genetic, dietary and/ or environmental variations.
