Circulating omentin-1 levels and inflammation in polycystic ovary syndrome. Franik G et al. (2020) The aim of the study was to analyze interrelation between plasma omentin-1 levels and nutritional status and inflammation in PCOS. A cross-sectional study involving 86 PCOS (47 obese) and 72 Non-PCOS women (41 obese) determined anthropometric parameters and body composition. Serum glucose, insulin and omentin-1, TNF-α, sTNFRs, IL-6 and sR-IL6 were measured in the fasting state. Plasma omentin-1 levels were significantly lower in the PCOS than in the Non-PCOS group and both corresponding normal weight and obese subgroups. In three analyzed least-angle regression (LARS) models the lower plasma omentin- 1 levels was associated with PCOS occurrence, higher circulating TNF-α and lower IL-6 levels. Suppressed omentin-1 levels in PCOS are characteristic for this disturbance and proinflammatory cytokines are factors modifying secretion of this adipokine.//////////////////
Circulating omentin-1 levels in women with polycystic ovary syndrome: a meta-analysis. Tang YL et al. (2016) To investigate the association between circulating omentin-1 levels and polycystic ovary syndrome (PCOS) in women, a meta-analysis was performed. A systematic literature search using PubMed, Embase and Web of Science was carried out. Ten articles with 13 studies were included in this meta-analysis, which included a total of 1264 subjects (733 patients with PCOS and 531 controls). The pooled standard mean difference (SMD) and 95% confidence interval (CI) were used to estimate the association between omentin-1 levels and PCOS. Circulating omentin-1 levels were lower in PCOS with an SMD (95% CI) of -0.67 (-0.91, -0.43) and p = 0.000 (random-effects). However, significant heterogeneity was detected across studies (I(2)=73.6% and p = 0.000). The subgroup analysis suggested that omentin-1 levels in PCOS patients were associated with HOMA-IR ratio. Meta-regression analysis indicated region was the main source of heterogeneity (p = 0.048). The results of this meta-analysis suggested that circulating omentin-1 levels are significantly lower in women with PCOS compared with controls, which indicated that omentin-1 may play a role in the pathologic processes of PCOS.//////////////////
Plasma omentin-1 levels are reduced in non-obese women with normal glucose tolerance and polycystic ovary syndrome. Choi JH et al. (2011) Omentin-1 is a novel adipokine that increases insulin sensitivity and is expressed in visceral adipose tissue. The aim of this study was to determine the metabolic parameters that influence plasma omentin-1 levels in women with polycystic ovary syndrome (PCOS). A cross-sectional study was performed in 87 women with PCOS and 53 body mass index (BMI)-matched healthy controls including 39 non-obese, normal-weight (NW) PCOS women with normal glucose tolerance (NGT) and 44 BMI- and homeostasis model assessment (HOMA)-matched controls. Indices of insulin sensitivity, metabolic variables, circulating androgen levels, serum adiponectin, and omentin-1 levels were measured. A 75 g oral glucose tolerance test was performed in all participants. Plasma omentin-1 levels were significantly lower in women with PCOS compared with those in BMI-matched controls (P<0.001). A significantly lower level of plasma omentin-1 was observed in non-obese women with PCOS and NGT compared with that in BMI- and HOMA-matched controls (P<0.001). Omentin-1 level was negatively correlated with BMI, indices of insulin sensitivity, and circulating androgens and was associated with greater 2 h postprandial glucose, C-peptide, and insulin levels compared with fasting values. Within the NW and NGT groups, omentin-1 levels remained negatively correlated with BMI, 2 h postprandial C-peptide, and circulating androgens and demonstrated a negative linear trend according to quartile of free testosterone (P=0.028). Plasma levels of omentin-1 were reduced in non-obese women with PCOS and NGT. Postprandial hyperinsulinemia and hyperglycemia contributed more to lower omentin-1 levels than did fasting values in the setting of PCOS. Increased androgen levels contributed to decreased omentin-1 levels in women with PCOS.//////////////////
Ovarian function
Comment
The correlation of plasma omentin-1 with insulin resistance in non-obese polycystic ovary syndrome. Yang HY et al. (2015) Aberrant circulating adipokines are considered to be related to the pathological mechanism of polycystic ovary syndrome (PCOS). This study aims to evaluate the relationship between plasma omentin-1 levels, metabolic and hormonal parameters in the setting of non-obese Chinese women with PCOS. This was a case-controlled, cross-sectional study of 153 non-obese (BMI<25kg/m(2)) PCOS and 114 age-matched healthy non-obese control individuals. Levels of plasma omentin-1, fasting blood glucose, insulin and sexual hormones and ovary volume were analyzed in all subjects. Plasma omentin-1 levels of non-obese PCOS individuals were significantly lower than in healthy non-obese controls. Body Mass Index (BMI), homeostasis model of assessment for insulin resistance index (HOMA-IR), levels of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), LH/FSH ratio and ovary volume (OV) were significantly higher in subjects with PCOS than controls. In the HOMA-IR stratified subgroups, PCOS individuals with insulin resistance had lower omentin-1 than those without insulin resistance after BMI adjustment. Omentin-1 was negatively correlated with BMI, HOMA-IR and fasting insulin. Multiple linear regressions revealed that BMI contributed to omentin-1 levels. Ovary volume was negatively correlated to HOMA-IR but had no correlation with omentin-1. Plasma omentin-1 concentrations were decreased in the non-obese PCOS group. Insulin resistance could further decrease plasma omentin-1 in non-obese individuals with PCOS independent of BMI status.//////////////////
Expression regulated by
Growth Factors/ cytokines, insulin
Comment
Ovarian localization
Granulosa, Luteal cells, Follicular Fluid
Comment
Expression and Regulation of INTELECTIN1 (ITLN1) in Human Granulosa-Lutein Cells: Role in IGF1-Induced Steroidogenesis Through NAMPT. Cloix L 2014 et al.
INTELECTIN (ITLN) is an adipokine involved in the regulation of insulin sensitivity, inflammatory and immunity response. Serum ITLN levels are lower in obese, diabetic and polycystic ovary syndrome women as compared to control subjects. ITLN has never been studied in ovarian cells. Here, we identified ITLN1 in human ovarian follicles and investigated the molecular mechanisms involved in the regulation of its expression in response to insulin sensitizers, metformin and rosiglitazone, in the human granulosa-lutein cells (hLGCs) and in a human ovarian granulosa like tumor cell line (KGN). We also studied the effects of human recombinant ITLN1 (hRom1) on steroid production and on the activation of various signaling pathways. By RT-PCR, immunoblotting and immunohistochemistry, we found that INTL1 is present in human follicular cells. By ELISA, we showed that INTL levels are similar in plasma and follicular fluid (FF) in control patients whereas they are higher in FF than plasma in PCOS patients. In KGN and hLGCs, INSULIN (10(-8)M), IGF1 (10(-8)M) and metformin (10(-2)M or 10(-3)M) increase INTL1 expression (mRNA and protein) after 12 and 24 h of stimulation. For metformin this effect is mediated by PRKA (Adenosine Monophosphate-activated kinase). Furthermore, hRom increases NAMPT expression in KGN and hLGCs. We also showed that hRom1 increases IGF1-induced progesterone and estradiol secretion and this was associated with an increase in STAR and CYP19A1 protein levels and an increase in IGF1R signaling. Furthermore all these data were abolished when NAMPT was knocked down in KGN cells suggesting that INTL1 improves IGF1-induced steroidogenesis through induction of NAMPT in human granulosa-lutein cells.
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