CD68+ Microglial Landscape in Optic Pathway of Donated Cadavers: Correlation with Demographics and Comorbidities

Introduction: Microglia, is the resident immune cell of the central nervous system (CNS), playing a key role in maintaining homeostasis and responding to injury. This study investigates the spatial distribution of CD68+ microglia within the human optic pathway, examining the influence of age, gender, laterality, and co-morbidities (e.g., hypertension, diabetes) on microglial density across white and grey matter. Understanding distribution patterns is crucial for insights into neurodegenerative diseases affecting the optic pathway. Methods: Fifteen cadaveric brains (11 males, 4 females) were analysed. Tissue blocks from the optic nerve, optic chiasma, optic tract, and lateral geniculate body (LGB) were stained using CD68 immunohistochemistry to identify activated microglia. Counts were performed under 400X magnification across five non-overlapping fields per sample. Results: Microglial density was significantly higher in grey matter compared to white matter regions of the optic pathway, with a mean of 45.5 ± 24.4 cells in the LGB versus 33.1 ± 26.7 in white matter ( p = 0.011). Age-related trends showed higher microglial counts in individuals above 60 years. Gender differences were also observed with females showing higher median counts in age-matched samples. Donors with co-morbidities (hypertension, diabetes) exhibited a notable increase in CD68+ microglia, especially in gray matter regions. Conclusion: This study reveals distinct microglial distribution patterns within the optic pathway, affected by age, gender, and chronic health conditions. The findings underscore the potential role of microglia in neuroinflammatory and neurodegenerative processes associated with the optic pathway, supporting further research on microglial contributions to CNS health and disease.