Olfactory Dysfunction Associated with Cognitive Decline in an Elderly Population.

BACKGROUND: In many neurological disorders, including Alzheimer disease, early olfactory dysfunction is observed. OBJECTIVE: In order to determine if deficits in olfactory memory are present in the elderly and if olfactory dysfunction correlates with cognitive impairment in the aging population, olfactory testing has been done on seniors from the NuAge cohort accepting to participate in the Olfactory Response Cognition and Aging (ORCA) secondary sub-study. The t-Mini Mental Statement Examination and the Telephone Interview for Cognitive Status tests were done to assess cognition levels. RESULTS: Overall, 94% of the ORCA cohort displayed olfactory dysfunction. Deficits in olfactory memory were also present. A correlation was observed between olfactory function and cognitive test scores. Moreover, in women who smoked, there was an association between olfactory memory and cognitive scores. CONCLUSION: Our results suggest that olfactory dysfunction may predict impending cognitive decline and highlights the need for olfactory training in seniors to improve olfaction and overall well-being.

Organ-specific alteration in caspase expression and STK3 proteolysis during the aging process.

Caspases and their substrates are key mediators of apoptosis and strongly implicated in various physiological processes. As the serine/threonine kinase family is involved in apoptosis and serine/threonine kinase 3 (STK3) is a recently identified caspase-6 substrate, we assessed the expression and cleavage of STK3 in murine peripheral organs and brain regions during the aging process. We also assessed caspase-3, -6, -7, and -8 expression and activity in order to delineate potential mechanism(s) underlying the generation of the STK3 fragments observed and their relation to the apoptotic pathway. We demonstrate for the first time the cleavage of STK3 by caspase-7 and show that STK3 protein levels globally increase throughout the organism with age. In contrast, caspase-3, -6, -7, and -8 expression and activity vary significantly among the different organs analyzed suggesting differential effects of aging on the apoptotic mechanism and/or nonapoptotic functions of caspases throughout the organism. These results further our understanding of the role of caspases and their substrates in the normal aging process and highlight a potential role for STK3 in neurodegeneration.