An article from Genomics & Proteomics takes a broad look at changes in gene expression with aging - and hints of ways in which to intervene in the process. Interestingly, there is mention of developing biomarkers for physiological age: "We just now have molecular markers for aging in the kidney. If I did the same thing, we could have molecular markers for aging in the muscle, liver, or skin. These markers don't tell how many years you've lived; they tell your relative health. You could turn these into terrific clinical markers, and you would know whether someone is 40 and looks like they're on a bad trajectory, or if they're 80 and you could treat them as a 40-year-old." The current absence of meaningful biomarkers makes it difficult to usefully discuss the results of therapies.