Circulating biomarkers of nitro-oxidative stress in young and older active and inactive men

Abstract

Oxidative stress markers may be novel factors contributing to cardiovascular (CVD) risk. The purpose of this study was to examine the effects of long-term exercise, age, and their interaction on the plasma levels of the oxidative stress markers oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO), and to investigate whether these levels correlated with plasma NOx levels. Older (62 ± 2 yr) active (n=12) men who had exercised regularly for over 30 years and young (25 ± 4 yr) active (n=7) men who had exercised regularly for over 3 years were matched to older (n=11) and young (n=8) inactive males. Young subjects showed lower plasma nitrotyrosine levels than older subjects (P = 0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P = 0.042) or the older active (P = 0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional CVD risk factors, and in older subjects were associated with Framingham risk score (r = 0.49, P = 0.015). The study found no relationships between plasma markers of oxidative stress and plasma NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers may contribute to CVD risk.