RESUMO
BACKGROUND/OBJECTIVES: A high percentage of women having polycystic ovarian syndrome (PCOS) exhibit hyperinsulinemia and obesity. Transforming necrosis factor-α (TNF-α) is an adipokine that increases in obesity and negatively affects insulin action in several tissues, including the endometrium. In fact, it has been reported that insulin signaling is altered in the endometrium of PCOS women, affecting its reproductive function. The aim of this study was to determine the proinflammatory environment and TNF-α signaling in endometrium from obese women with PCOS, and also to evaluate the effect of TNF-α on endometrial cell energy homeostasis. METHODS: Serum and endometrial tissues were obtained from four study groups: normal-weight, normal-weight-PCOS, obese and obese-PCOS (hyperandrogenemia/hyperinsulinemia) (n=7 per group). Serum TNF-α level was assayed by enzyme-linked immunosorbent assay (ELISA); endometrial TNF-α level and its receptors (TNFR1/TNFR2) as well as nuclear factor (NF)-κB content were determined by immunohistochemistry. Finally, we evaluated TNF-α effect on glucose uptake in cultured human endometrial stromal cells (T-HESC) treated or not with testosterone/insulin resembling partially the PCOS condition. RESULTS: TNF-α plasma levels were similar between groups, whereas cytokine levels and macrophage number increased in endometrium from obese-PCOS women (P<0.001). Both receptor types were higher in obese vs normal-weight women, particularly TNFR2 content in the obese-PCOS group (P<0.001). Furthermore, an increased NF-κB nuclear content in endometrium from obese-PCOS was observed (P<0.001). Finally, TNF-α treatment of T-HESC cultures exhibited a decrease of glucose uptake (P<0.05), although similar to cells treated with testosterone or testosterone/insulin/TNF-α. CONCLUSIONS: These results suggest that the PCOS condition induces an inflammatory state exacerbated when obesity is present, where a higher TNF-α signaling is observed, all of which could affect glucose uptake in the tissue and may cause fertility failures in these women.
Assuntos
Endométrio/patologia , Endométrio/fisiopatologia , Inflamação/fisiopatologia , Obesidade/complicações , Obesidade/fisiopatologia , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/fisiopatologia , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Adiponectina/fisiologia , Adulto , Biomarcadores/metabolismo , Chile/epidemiologia , Feminino , Humanos , Hiperinsulinismo/etiologia , Hiperinsulinismo/fisiopatologia , Imuno-Histoquímica , Infertilidade Feminina/complicações , Infertilidade Feminina/etiologia , Infertilidade Feminina/fisiopatologia , Inflamação/complicações , Inflamação/metabolismo , Insulina/sangue , Obesidade/metabolismo , Síndrome do Ovário Policístico/metabolismo , Transdução de Sinais , Testosterona/metabolismoRESUMO
Hyperandrogenemia, hyperinsulinemia, and obesity affect 60-70% of patients with Polycystic Ovarian Syndrome (PCOS), who exhibit an altered endometrial insulin signaling. The aim of the study was to evaluate whether hyperandrogenism, hyperinsulinism, and obesity present in PCOS patients impair the endometrial adiponectin signaling pathway. The ex vivo study was conducted on 27 samples from lean (n=9), obese (n=9), and obese-PCOS (n=9) patients. The in vitro assays were performed in immortalized human endometrial stromal cells stimulated with testosterone, insulin, or testosterone plus insulin. Serum steroid-hormones, adiponectin, glucose, and insulin; body mass index, free androgen index, ISI-Composite, and HOMA were evaluated in the 3 groups. Ex vivo and in vitro gene expression and protein content of adiponectin, AdipoR1, AdipoR2, and APPL1 were determined. Adiponectin serum levels were decreased in obese-PCOS patients compared to lean (78%) and obese (54%) controls (p<0.05). AdipoR1 protein and gene expression were increased in obese group vs. obese-PCOS and lean groups (2-fold, p<0.05). In turn, AdipoR2 protein and mRNA content was similar between the 3 groups. APPL1 protein levels were reduced in endometria from both obese groups, compared to lean group (6-fold, p<0.05). Testosterone plus insulin stimulation of T-HESC and St-T1b leads to a reduction of adiponectin, AdipoR1, AdipoR2, and APPL1 protein content in both endometrial cell lines (p<0.05), whereas, in the presence of testosterone or insulin alone, protein levels were similar to basal. Therefore, endometrial adiponectin-signaling pathway is impaired in hyperandrogenemic and hyperinsulinemic obese-PCOS patients, corroborated in the in vitro model, which could affect endometrial function and potentially the implantation process.