Association of Androgen Excess with Glucose Intolerance in Women with Polycystic Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) show high prevalence of glucose intolerance. This study aimed to investigate the association of androgen excess with glucose intolerance in PCOS. A total of 378 women with PCOS participated in the study. Free androgen index (FAI) was selected as indicator of hyperandrogenism. Insulin sensitivity was assessed by 1/homeostasis model assessment of insulin resistance (1/HOMA-IR) and Matsuda insulin sensitivity index (ISIM); β-cell function was assessed by disposition index (DI). We found that women with glucose intolerance had higher FAI levels compared to women with normal glucose tolerance (NGT) (prediabetes 6.2, T2DM 7.9 versus NGT 5.0, resp.; p<0.001). Furthermore, there was a direct association between FAI levels and frequency of glucose intolerance (OR = 2.480, 95% CI 1.387–4.434), even after adjusting for age, BMI, waist circumference, hypertension, fasting insulin, testosterone, SHBG, and family history of diabetes. In addition, with FAI increase, glycosylated hemoglobin (HbA1c), plasma glucose concentrations, and serum insulin levels increased, while insulin sensitivity and β-cell function decreased. Our results suggested that androgen excess indicated by high FAI levels might serve as indicator of glucose intolerance, as it might promote insulin resistance and β-cell dysfunction in women with PCOS

DHEA-induced ovarian hyperfibrosis is mediated by TGF-β signaling pathway

Abstract Background The polycystic ovary syndrome (PCOS) is a common metabolic and endocrine disorder with pathological mechanisms remain unclear. The following study investigates the ovarian hyperfibrosis forming via transforming growth factor-β (TGF-β) signaling pathway in Dehydroepiandrosterone (DHEA)- induced polycystic ovary syndrome (PCOS) rat model. We furthermore explored whether TGF-βRI inhibitor (SB431542) decreases ovarian fibrosis by counterbalancing the expression of fibrotic biomarkers. Methods Thirty female Sprague-Dawley rats were randomly divided into Blank group (n = 6), Oil group (n = 6), and Oil + DHEA-induced model group (n = 6 + 12). The model groups were established by subcutaneous injection of DHEA for 35 consecutive days. The 12 successful model rats were additionally divided in vehicle group (n = 6) and SB431542-treated group (n = 6). Vehicle group and SB431542-treated group, served as administration group and were intraperitoneally injected with DMSO and SB431542 for additional 14 consecutive days. Ovarian morphology, fibrin and collagen localization and expression in ovaries were detected using H&E staining, immunohistochemistry and Sirius red staining. The ovarian protein and RNA were examined using Western blot and RT-PCR. Results In DHEA-induced ovary in rat, fibrin and collagen had significantly higher levels, while the main fibrosis markers (TGF-β, CTGF, fibronectin, a-SMA) were obviously upregulated. SB431542 significantly reduced the expression of pro-fibrotic molecules (TGF-β, Smad3, Smad2, a-SMA) and increased anti-fibrotic factor MMP2. Conclusion TGF-βRI inhibitor (SB431542) inhibits the downstream signaling molecules of TGF-β and upregulates MMP2, which in turn prevent collagen deposition. Moreover, ovarian hyperfibrosis in DHEA-induced PCOS rat model could be improved by TGF-βRI inhibitor (SB431542) restraining the transcription of accelerating fibrosis genes and modulating EMT mediator

DataSheet_1_Placenta-derived exosomes exacerbate beta cell dysfunction in gestational diabetes mellitus through delivery of miR-320b.docx

Recent studies have shown placenta-derived exosome (pdE) acts as an important mediator of organ-to-organ interplay regulating maternal metabolic alterations, however, the function and mechanisms of placental exosomes on pancreatic β-cell maladaptation in gestational diabetes mellitus (GDM) remain unclear. The purpose of this investigation was to ascertain how placental exosomes affected the β-cell dysfunction associated with the onset of GDM. Exosomes were isolated from chorionic villi explants of pregnant mice and humans with normal glucose tolerance (NGT) and GDM. The effects of pdE from GDM on glucose tolerance in vivo and islets function in vitro were determined. Isolated islets from mice fed on the chow diet displayed an increase in apoptosis and observed their glucose-stimulated insulin secretion (GSIS) greatly diminished by PdE from GDM mice. Mice that accepted PdE from mice with GDM possessed glucose intolerance.Based on miRNA microarray assay and bioinformatics analysis from human placental exosomes, we identified miR-320b selectively enriched in PdE secreted in GDM compared with NGT. Importantly, the level of placental miR-320b was positively correlated with the 1h-glucose and 2-h glucose of a 75 g oral glucose tolerance test (OGTT) during human pregnancies. Furthermore, miR-320 overexpression attributed to impaired insulin secretion and increased apoptosis in MIN6 cells and islets obtained from mice with normal insulin sensitivity. This study firstly proposed that altered miRNAs in pdE contribute to defective adaptation of β cells during pregnancy, which expands the knowledge of GDM pathogenesis. Exosomes from the placenta may be an emerging therapeutic target for GDM.</p

Insulin resistance enhances the mitogen-activated protein kinase signaling pathway in ovarian granulosa cells.

The ovary is the main regulator of female fertility. Granulosa cell dysfunction may be involved in various reproductive endocrine disorders. Here we investigated the effect of insulin resistance on the metabolism and function of ovarian granulosa cells, and dissected the functional status of the mitogen-activated protein kinase signaling pathway in these cells. Our data showed that dexamethasone-induced insulin resistance in mouse granulosa cells reduced insulin sensitivity, accompanied with an increase in phosphorylation of p44/42 mitogen-activated protein kinase. Furthermore, up-regulation of cytochrome P450 subfamily 17 and testosterone and down-regulation of progesterone were observed in insulin-resistant mouse granulosa cells. Inhibition of p44/42 mitogen-activated protein kinase after induction of insulin resistance in mouse granulosa cells decreased phosphorylation of p44/42 mitogen-activated protein kinase, downregulated cytochrome P450 subfamily 17 and lowered progesterone production. This insulin resistance cell model can successfully demonstrate certain mechanisms such as hyperandrogenism, which may inspire a new strategy for treating reproductive endocrine disorders by regulating cell signaling pathways

Additional file 1: Figure S1. of DHEA-induced ovarian hyperfibrosis is mediated by TGF-β signaling pathway

The serum testosterone (T) and (Estrogen) E2/T levels in control, DHEA and SB431542-treated rats. *p ≤ 0.05, ***p ≤ 0.002. Data are shown as mean ± SEM. Figure S2. The estrous cycle of DHEA-induced PCOS rats disordered. (A) The estrous cycle of the Blank group, Oil group and Oil + DHEA group rats. The abscissa indicates the age of rats. In the proestrus, many nucleated epithelial cells (NEC) were observed. In the estrus, high number of corneous cells (CC) were detected. In the metestrus, visible nucleated epithelial cells, corneous cells and leucocyte (L) were discovered. In the diestrus, a mass of leucocyte can be seen in the field of view. (B) Microscopic examination of vaginal smears stained by toluidine blue. × 200.. D = diestrus; P = proestrus; E = estrus; M = metestrus. Figure S3. The hormone levels after SB431542 treatment. (A) Serum total T levels; (B) E2/T of serum. (DOCX 467 kb

Testosterone (T), estradiol (E2) and progesterone (P4) production by GCs.

<p>GCs were incubated in the absence (Con) or presence of Dex for 48 h (GD) or Dex for 48 h with PD98059 added 4 h before the end of the incubation (GDP). Data presented are representative of at least three separate experiments. *p < 0.05.</p

Mitogen-activated protein kinase (MAPK) and phosphor-p44/42 MAPK (P-MAPK) protein expression in GCs.

<p>GCs were incubated in the absence (Con) or presence of Dex for 48 h (GD) or Dex for 48 h with PD98059 added 4 h before the end of the incubation (GDP). Relative density ratios were calculated by setting the control group value as one. Data are expressed as the mean + SEM. All data presented are representative of at least three separate experiments. *p < 0.05, ***p < 0.001.</p

Effects of Dex and PD98059 on GC proliferative activity.

<p>GCs were incubated in the absence (Con) or presence of Dex for 48 h (GD) or Dex for 48 h with PD98059 added 4 h before the end of the incubation (GDP). GC proliferative activity was measured by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) method. Data are expressed as the mean + SEM. All data presented are representative of at least three separate experiments. *p < 0.05, **p < 0.01.</p