Risk analysis of systemic levels of estrogen and adipokines as well as estrogen receptors from PBMCs in childbearing and perimenopausal women with obesity

PURPOSE: We aimed to evaluate the clinical value of systemic levels of estrogen and adipokines as well as estrogen receptors from peripheral blood mononuclear cells (PBMCs) in childbearing and perimenopausal women with obesity. SUBJECTS AND METHODS: We observed 292 women, including 160 perimenopausal women (80 with obesity and 80 without obesity) and 132 women of childbearing age (67 with obesity and 65 without obesity). Body parameters, such as body mass index and waist circumference, were measured. Fat distribution was evaluated using a computerized tomography scanner. The levels of serum estrogen, leptin, visfatin, and adiponectin were measured using an enzyme-linked immunosorbent assay. The expression of circulating ERs was evaluated by Western blot analysis. RESULTS: Perimenopausal women and childbearing women with obesity exhibited lower levels of estrogen and adiponectin, in addition to a distribution of visceral fat with higher levels of leptin and visfatin. These findings reflect the current data of menopausal women, which confirms the reliability of this experimental system. However, the expression of ERα in peripheral blood was significantly enhanced in women with obesity of both childbearing and perimenopausal age. This result is contrary to the common understanding of adipose tissue, namely that ERα is protective. The expression of ERβ in the women without obesity of both childbearing and perimenopausal age was higher than in women with obesity, which coincides with the results of a previous study on adipose tissue. CONCLUSION: Our data fundamentally contradicts the utility of circulating ERα and ERα/ERβ evaluations in obesity studies. Because estrogen exerts pleiotropic effects on multiple tissues in the body through differential regulation of ERs, although the expression of ERβ coincides with the results of a previous study on adipose tissue, the expression levels of ERs in blood cannot be used as a diagnostic of informative tool for obesity in women.