Oxidative stress induces age-dependent changes in lymphocyte protein synthesis and second messenger levels

Cumulative damage in cells from aged people could lead to a greater fragility against acute oxidative stress. The effects of acute oxidative stress on cell viability, cAMP and cGMP concentrations, and protein synthesis rates were studied in lymphocytes from 25 young and 26 elderly subjects. Lymphocytes were exposed to stress by hydrogen peroxide 25 micromol/l and incubated for 18 hours. Cell viability after stress was lower (p<0.0001, Student's t test) in cells from the elderly (63.4%) than in cells from the young donors (73.2%). The protein synthesis rate was also lower after stress (p<0.04, Mann-Whitney U test) in cells from the elderly (47.3% vs. non-stressed cells), than in cells from the young (82.19% vs. non-stressed cells). After oxidative stress, cAMP and cGMP concentrations showed no significant changes in cells from young subjects; there were, however, significant decreases in these cyclic nucleotides in cells from the elderly (p<0.008 for both nucleotides, paired Student's t test). There were no differences in basal cAMP or cGMP levels between the two groups. These results show that mortality and metabolic changes due to oxidative stress are greater in lymphocytes proceeding from elderly subjects than in those from young subjects.