Comparison of plasma antioxidant levels in middle-aged and old male with idiopatic osteoporosis: preliminary data

OBJECTIVES: With the purpose of evaluating the role of oxidative stress (OS) in male idiopatic osteoporosis, we have evaluated plasma total antioxidant capacity (TAC) in pa - tients classified according to age (< 65 or ≥ 65 yrs), with normal hormone values and in age- matched healthy control subjects. PATIENTS AND METHODS: TAC was evaluat - ed with a colorimetric method, using the sys - tem metamyoglobin-H2O2 and the chromogen ABTS; the latency time (LAG, sec) in the ap - pearance of ABTS radical species is propor - tional to antioxidant content of the system. RESULTS: We found slightly increased LAG val - ues in middle-aged patients, compared with age- matched controls, probably expression of a com - pensatory mechanism to OS; on the contrary aged patients showed significantly lower LAG values in comparison with age-matched controls, suggesting a defective compensatory mecha - nism and, therefore, a risk for oxidative damage. CONCLUSIONS: OS could be a possible mechanism underlying male osteoporosis, both in middle-aged and aged patients, but compen - satory mechanisms seem to be defective in the last group.