Caspases and their substrates are key mediators of apoptosis and strongly implicated in various physiological processes. As the STK family is involved in apoptosis, and 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 amongst the different organs analyzed suggesting differential effects of aging on the apoptotic mechanism and/or non-apoptotic 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.3

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Deterioration of olfaction is a common phenomenon observed in the senior population. A number of factors may cause this deficit including infections, aging and neurodegenerative diseases. The aim of this study was to evaluate the reliability of the self-report as a measure of olfactory function in seniors. A total of 93 community-dwelling participants (43 men and 50 women) from the Quebec NuAge cohort on Nutrition and Successful Aging participated in the Olfactory Response and Cognition in Aging (ORCA) study. The age range was 80-95 years and all subjects had a telephone mini mental state examination (t-MMSE) score > 18. Individuals were interviewed using a self-report ("do you suffer from smell problems?'') and quantitative (University of Pennsylvania Smelling Identification Test (UPSIT)) olfactory tests. Based on the self-report, 81% of the participants claimed to have a normal sense of olfaction. However, based on the UPSIT, 95% of them showed different forms of microsmia. These results reveal that most senior citizens are unaware of their olfactory dysfunction and indicate that an self-report questionnaire is not a valid instrument to assess olfactory function in the aging population.