Researchers are very interested in establishing biomarkers of aging and longevity, as at present the only truly reliable way to distinguish between long-lived and not so long-lived individuals is to wait and see what happens - which isn't an efficient way to run studies of potential therapies for aging. Here's an example of one line of investigation: "Wound healing (WH) is a fundamental biological process. Is it associated with a longevity or aging phenotype? In an attempt to answer this question, we compared the established mouse models with genetically modified life span and also an altered rate of WH in the skin. Our analysis showed that the rate of skin WH in advanced ages (but not in the young animals) may be used as a marker for biological age, i.e., to be indicative of the longevity or aging phenotype. The ability to preserve the rate of skin WH up to an old age appears to be associated with a longevity phenotype, whereas a decline in WH with an aging phenotype. In the young, this relationship is more complex and might even be inversed. While the aging process is likely to cause wounds to heal slowly, an altered WH rate in younger animals could indicate a different cellular proliferation and/or migration capacity, which is likely to affect other major processes such as the onset and progression of cancer. As a point for future studies on WH and longevity, using only young animals might yield confusing or misleading results, and therefore including older animals in the analysis is encouraged."