Biomarkers of aging: tissue markers. Future research needs, strategies, directions and priorities.

Objective tests that allow early detection of deleterious changes with age are necessary to develop treatments enhancing the health span--the length of healthy life. Here we report tests of eight biological systems that can be performed in mice with no harm to the subjects. Male and female B6, CBA and F1 mice were used. While most test results correlated with chronological age in most genotypes, none predicted subsequent longevities in more than two genotypes. Surprisingly, the open field activity test that most consistently predicted longevities, did not correlate with chronological age. Six tests predicted beneficial effects of food restriction in F1 males, but only one correctly predicted the deleterious effects of the same food restriction regimen in B6 males. These results suggest that different biological systems age at different rates, that rates are affected by genotype and that an anti-aging treatment beneficial in one genotype may be harmful in another.