Vascular function of forearm microcirculation in postmenopausal women with type 2 diabetes: potential benefit of hormone replacement therapy?

Objective: To study the potential effects of hormone replacement therapy (HRT) on vascular function of the peripheral circulation in postmenopausal women with type 2 diabetes. Methods: Seventeen premenopausal women aged 47.4 ± 4.4 years (PreM), 23 nondiabetic postmenopausal women aged 59.4 ± 7.0 years (PM), 15 postmenopausal women with type 2 diabetes aged 60.3 ± 7.2 years (PMD) and 12 postmenopausal women with type 2 diabetes using HRT aged 61.2 ± 4.0 years (PMDHRT) were studied. Vascular function of the peripheral circulation was investigated by measuring hyperemic responses of the forearm microcirculation following an ischemic stimulus using venous occlusion, strain-gauge plethysmography. Fasting lipids, glucose and glycated hemoglobin (HbA1c) were also measured. Results: Forearm vascular function was significantly impaired in the PMD group: maximal blood flow (ml/100 ml/min) was 15.23 ± 8.19 vs. 28.21 ± 12.30 (PreM), 23.62 ± 6.62 (PM) and 23.37 ± 5.78 (PMDHRT) (p = 0.004); flow debt (ml/100 ml) was 3.99 ± 2.83 vs. 7.40 ± 4.92 (PreM), 5.66 ± 3.67 (PM) and 8.57 ± 4.84 (PMDHRT) (p = 0.0018); vascular resistance (mmHg/ml/100 ml/min) was 11.90 ± 9.02 vs. 5.04 ± 2.41 (PreM), 5.55 ± 2.69 (PM) and 5.96 ± 1.88 (PMDHRT) (p = 0.003). Fasting lipids, HbA1c and body mass index were not significantly different between the two diabetic groups. Conclusions: Postmenopausal women with diabetes have abnormal vascular function of resistance arteries that may improve with HRT. HRT may therefore reduce cardiovascular risk in postmenopausal women with type 2 diabetes, and a clinical end-point trial is warranted to test this hypothesis.