Microcirculatory function in postmenopausal women: role of aging, hormonal exposure and metabolic syndrome.

Menopausal hormone therapy (HT) has shown conflicting cardiovascular endpoints, depending on the women studied. The endothelium is the main site for sex steroids cardiovascular action. To assess the influence of age, previous hormonal exposure and of metabolic syndrome (MS) on microcirculatory function, we studied 68 normotensive non-diabetic postmenopausal women, 34-70 years old, by dynamic nailfold videocapillaroscopy evaluating red blood cell velocity (RBCV) at baseline and during the reactive hyperemia response after 1 min ischemia (RBCV(max)) and time taken to reach it (TRBCV(max)). There was an inverse correlation between RBCV and RBCV(max), versus age (p=0.02 for both) and time since menopause (TSM, p=0.01 and p=0.03, respectively). Women who used oral contraceptives in the past showed higher RBCV (1.51+/-0.10 vs. 1.43+/-0.09 mm/s, p=0.01) and RBCV(max) (1.70+/-0.11 vs. 1.63+/-0.07 mm/s, p=0.03) compared to never user ones. A longer time after menopause without HT was associated to lower RBCV(max) (p=0.05). Women with MS had longer TRBCV(max) (9.85+/-1.77 vs. 8.47+/-1.71 s, p=0.02), as well as those with higher hematocrit, hemoglobin and leukocyte counts (p=0.03, p=0.01 and p=0.03, respectively) and lower HDL (p=0.03). In conclusion, in postmenopausal women of low cardiovascular risk, advanced age, longer TSM, longer time after menopause without HT and MS were associated to microcirculatory function impairment, whereas past use of oral contraceptives seemed to have a protective effect.