Patterns of Senescence

Do all tissues of the fly age together and at the same rate? Our early work suggested that both normal- and long-lived animals undergo the same sort of senescent process, losing different traits in the same sequence and at the same stage (Arking and Wells, 1992). Since the animals do not lose all functions at the same time, it also implies that different tissues age at different rates. Is there any data to support this implication? The fact that there is a defined spatio-temporal pattern of gene expression during the aging process (Seyroude et al., 2002), coupled with the fact that at least 9% of the genes are known to undergo transcriptional changes during aging (Pletcher et al., 2002), suggests that it is unlikely that all tissues of the fly age together and at the same rate. Some data to support this supposition were presented by Cook-Wiens and Grotewiel (2002). They showed that different behaviors of the fly, utilizing different sensory systems, age at different rates. For example, locomotor and olfactory performance decreases with age even while the aging animal maintains its ability to respond to electric shock and light. Different sensory-motor behaviors decline at different rates within the same animal. What is most interesting is the fact that these olfactory and locomotor declines occurred at the same rate and at the same times in normal-lived control animals as they did in long-lived stress-resistant (mth) mutants. Thus genetic manipulations that enhance resistance to oxidative stress and extend life span do not necessarily protect against functional senescence in all pathways. We not only age in an individual manner, but each individual ages in a heterogeneous manner.

How to Stay Young

How to Stay Young

For centuries, ever since the legendary Ponce de Leon went searching for the elusive Fountain of Youth, people have been looking for ways to slow down the aging process. Medical science has made great strides in keeping people alive longer by preventing and curing disease, and helping people to live healthier lives. Average life expectancy keeps increasing, and most of us can look forward to the chance to live much longer lives than our ancestors.

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