Coenzyme Q10, a cutaneous antioxidant and energizer

Epidermal cell renewal was assessed nonintrusively in normal human volunteers by monitoring the disappearance of a fluorescent marker dye, dansyl chloride, from the skin surface. In young adults, stratum corneum transit time was approximately 20 days, whereas in older adults this was lengthened by more than 10 days. Because the number of horny cell layers does not change with age, these data indicate that the increased stratum corneum transit time was a reflection of diminished epidermal cell proliferation. Additional analysis indicated that the decline in epidermal cell renewal may not occur at a constant rate throughout the adult lifespan but, instead, remains relatively constant in the younger years and then begins to drop dramatically after age 50. This suggests that a linear-spline model rather than a simple linear model may be more appropriate for analyzing these results.

To review recent progress and consider future approaches for basic research on aging with clinical applicability. Peer-reviewed publications on experimental gerontology and geriatrics. Studies were selected that described experimental approaches in gerontology and geriatrics, starting with the evolutionary basis of aging, through theories trying to explain its major causes, to novel experimental approaches, e.g., computer informatics, protein chemistry and genetics. Our increased understanding of the evolutionary basis of aging has made it possible to consider a number of experimental strategies more rationally. Most theories on the causes of aging involve some kind of somatic damage that accumulates with age, the rate of which is determined by environmental, genetic, and behavioral factors. The recent emergence of more powerful methodology offers new possibilities for identifying basic mechanisms of aging, which would increase our understanding of biologically based susceptibility to age-related health problems. There is a growing awareness that age-related deterioration will affect an ever growing number of people, in both absolute and relative terms. It can be expected that this will further increase the resources that will be made available for research on aging. Although ultimately unavoidable, aging is a process that appears to be experimentally accessible. Therefore, the mechanisms of senescence and death may eventually be more completely understood, with the promise of preventing and/or delaying many of the adverse effects associated with aging, including most of the common diseases, and possibly also of extending lifespan.