Relation between corticotropin-releasing hormone neuron number in the hypothalamic paraventricular nucleus and depressive state in Alzheimer's disease

BACKGROUND/AIMS: Depression occurs in 20-50% of the Alzheimer disease (AD) patients. It is not known whether depression in AD shares its pathophysiology with depressive disorder. Previously we found a fourfold increase of corticotropin-releasing hormone (CRH)-immunoreactive (IR) neurons in the hypothalamic paraventricular nucleus in depression. The objective of the present study was to find out whether in depression in AD the same phenomenon of an increased number of CRH-IR neurons could be observed. METHODS: Post-mortem brain tissue was obtained from a cohort of 23 AD patients prospectively studied using the Cornell Scale for Depression in Dementia to measure depressive symptoms. The number of CRH-IR neurons was determined using immunocytochemistry and the Image Pro Plus analysis program. RESULTS: A significant positive correlation was found between the Cornell scores and the number of CRH-IR neurons (p = 0.039) in AD patients. CONCLUSION: These results suggest that depressive disorder and depression in AD share, at least partly, their pathophysiology.