Novel adipokines WISP1 and betatrophin in PCOS: relationship to AMH levels, atherogenic and metabolic profile

Integrated lipid metabolomics and proteomics analysis reveal the pathogenesis of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrinological and metabolic disorder that can lead to female infertility. Lipid metabolomics and proteomics are the new disciplines in systems biology aimed to discover metabolic pathway changes in diseases and diagnosis of biomarkers. This study aims to reveal the features of PCOS to explore its pathogenesis at the protein and metabolic level.

METHODS

We collected follicular fluid samples and granulosa cells of women with PCOS and normal women who underwent in vitro fertilization(IVF) and embryo transfer were recruited. The samples were for the lipidomic study and the proteomic study based on the latest metabolomics and proteomics research platform.

RESULTS

Lipid metabolomic analysis revealed abnormal metabolism of glycerides, glycerophospholipids, and sphingomyelin in the FF of PCOS. Differential lipids were strongly linked with the rate of high-quality embryos. In total, 144 differentially expressed proteins were screened in ovarian granulosa cells in women with PCOS compared to controls. Go functional enrichment analysis showed that differential proteins were associated with blood coagulation and lead to follicular development disorders.

CONCLUSION

The results showed that the differential lipid metabolites and proteins in PCOS were closely related to follicle quality,which can be potential biomarkers for oocyte maturation and ART outcomes.

Opportunities and challenges: interleukin-22 comprehensively regulates polycystic ovary syndrome from metabolic and immune aspects

Polycystic ovary syndrome (PCOS) is known as a prevalent but complicated gynecologic disease throughout the reproductive period. Typically, it is characterized by phenotypic manifestations of hyperandrogenism, polycystic ovary morphology, and persistent anovulation. For now, the therapeutic modality of PCOS is still a formidable challenge. Metabolic aberrations and immune challenge of chronic low-grade inflammatory state are significant in PCOS individuals. Recently, interleukin-22 (IL-22) has been shown to be therapeutically effective in immunological dysfunction and metabolic diseases, which suggests a role in the treatment of PCOS. In this review, we outline the potential mechanisms and limitations of IL-22 therapy in PCOS-related metabolic disorders including its regulation of insulin resistance, gut barrier, systemic inflammation, and hepatic steatosis to generate insights into developing novel strategies in clinical practice.

Recent progress on the role of cellular communication network factors (CCN) 3, 4 and 6 in regulating adiposity, liver fibrosis and pancreatic islets

CCN/WISP (cellular communication network factors, or Wnt-inducted secreted proteins) family of proteins consists of six extracellular matrix (ECM)-associated proteins that regulate development, cell adhesion and proliferation, ECM remodeling, inflammation, and tumorigenesis. In the last two decades, metabolic regulation by these matricellular proteins has been studied extensively, several excellent reviews have covered the roles of CCN1, -2 and - 5. In this brief review, we will focus on those lesser-known members and more recent discoveries, together with other recent articles presenting a more complete picture of the current state of knowledge. We have found that CCN2, -4, and - 5 promote pancreatic islet function, while CCN3 plays a unique and negative role. CCN3 and - 4 are pro-adiposity leading to insulin resistance, but CCN5 and - 6 are anti-adiposity. While CCN2 and - 4 promote tissue fibrosis and inflammation, all other four members are clearly anti-fibrotic. As for cellular signaling, they are known to interact with integrins, other cell membrane proteins and ECM thereby regulate Akt/protein kinase B, myocardin-related transcription factor (MRTF), and focal adhesion kinase. Yet, a cohesive mechanism of action to comprehensively explain those major functions is still lacking.

Impact of Obesity on Anti-Mullerian Hormone (AMH) Levels in Women of Reproductive Age

Obesity negatively impacts reproductive health, including ovarian function. Obesity has been posited to alter Anti-Müllerian hormone (AMH) production. Understanding biological factors that could impact AMH levels is necessary given the increasing use of AMH for predicting reproductive health outcomes in response to controlled ovarian stimulation, diagnosing ovulatory disorders, onset of menopause, and natural conception. In this narrative review, we evaluated the impact of obesity on AMH levels in healthy, regularly cycling reproductive-age women (18-48 years). Thirteen studies (n = 1214 women; (811, non-obese (body mass index; BMI < 30 kg/m2); 403, obese (BMI > 30 kg/m2))) were included, of which five reported decreased AMH levels with obesity, whereas eight showed comparable AMH levels between groups. Inclusion of women with higher obesity classes (Class 3 versus Class 1) may have been a factor in studies reporting lower AMH levels. Together, studies reporting AMH levels in otherwise healthy women remain limited by small sample sizes, cross-sectional designs, and lack of representation across the entire adiposity spectrum. Ultimately, the degree to which obesity may negatively impact AMH levels, and possibly ovarian reserve, in otherwise healthy women with regular menstrual cycles should be deemed uncertain at this time. This conclusion is prudent considering that the biological basis for an impact of obesity on AMH production is unknown.

Increased Serum WISP1 Levels are Associated with Lower Extremity Atherosclerotic Disease in Patients with type 2 Diabetes Mellitus

BACKGROUND

Serum wnt1-induced signaling pathway protein 1 (WISP1) levels are increased with obesity, which is a common complication associated with lower extremity atherosclerotic disease (LEAD). However, to date, the relationship between elevated WISP1 levels and the incidence of lower extremity atherosclerotic disease (LEAD) in type 2 diabetes mellitus (T2DM) remains unclear.

METHODS

174 newly diagnosed type 2 diabetic patients were enrolled in our study. Patients were divided into two groups, LEAD group (n=100) and control group (n=74). Anthropometric parameters, blood pressure and some biochemical parameters were obtained. Body composition was detected by bioelectrical impedance analysis (BIA). Levels of serum insulin were determined by radioimmunoassay. Serum WISP1 and interleukin 6 (IL-6) levels were determined using an enzyme-linked immunosorbent assay.

RESULTS

It was shown that serum WISP1 levels in diabetic patients with LEAD were higher than those without LEAD (P<0.001). Serum WISP1 levels were positively related with waist circumference (r=0.237, P=0.003), waist-hip ratio (r=0.22, P=0.006), visceral fat area (r=0.354, P<0.001), serum creatinine (r=0.192, P=0.012), interleukin 6 (r=0.182, P=0.032), c-reactive protein (r=0.681, P<0.001), triglycerides (r=0.119, P<0.001), fasting glucose (r=0.196, P=0.011), glycated hemoglobin (r=0.284, P<0.001), and HOMA-IR (r=0.285, P<0.026). Compared with the lowest tertile, the odds ratio of the middle tertile for LEAD incidence was 3.27 (95% CI, 1.24-8.64) and 4.46 (95% CI, 1.62-12.29) for the highest tertile after adjusting confounding factors.

CONCLUSION

The results suggest that increased serum WISP1 levels independently contribute to the incidence of LEAD in patients with newly diagnosed T2DM.

ANGPTL8 roles in proliferation, metabolic diseases, hypothyroidism, polycystic ovary syndrome, and signaling pathways

A new and atypical member of the ANGPTL family is angiopoietin-like protein 8 (ANGPTL8). This newly discovered hormone is a drug target that can be used to treat diabetes and dyslipidemia. The protein, as a hepatocyte-derived circulating factor, can control the triglyceride level of plasma. ANGPTL8 is significantly associated with inflammation and metabolic syndrome consequences such as obesity, diabetes, hypothyroidism, and PCOS. ANGPTL8 gene has four exons encoding a 22/5 kDa weight of 198 amino acid polypeptides. A highly preserved ANGPTL8 gene among mammals exhibits the essential hormone functions of ANGPTL8. Nevertheless, the physiological function of this hormone in the body is poorly understood. Studies published in PubMed (2008-2020), Google Scholar (2004-2020), and Scopus (2004-2020) databases of clinical trials were reviewed. This analysis is aimed at collecting information on ANGPTL8. The emphasis of this review was on gathering information about the role of ANGPTL8 in the metabolism of glucose and lipids and cell proliferation. It addition to the different roles of ANGPTL8 in diabetes and lipid metabolism, this review emphasized on the protein role in signaling pathways. The study also proposes the signaling pathways that may be considered as a new target for treatment.

An Update to the WISP-1/CCN4 Role in Obesity, Insulin Resistance and Diabetes

Insulin resistance refers to the diminished response of peripheral tissues to insulin and is considered the major risk factor for type 2 diabetes. Although many possible mechanisms have been reported to develop insulin resistance, the exact underlying processes remain unclear. In recent years, the role of adipose tissue as a highly active metabolic and endocrine organ, producing proteins called adipokines and their multidirectional activities has gained interest. The physiological effects of adipokines include energy homeostasis and insulin sensitivity regulation. In addition, an excess of adipose tissue is followed by proinflammatory state which results in dysregulation of secreted cytokines contributing to insulin resistance. Wingless-type (Wnt) inducible signalling pathway protein-1 (WISP-1), also known as CCN4, has recently been described as a novel adipokine, whose circulating levels are elevated in obese and insulin resistant individuals. Growing evidence suggests that WISP-1 may participate in the impaired glucose homeostasis. In this review, we characterize WISP-1 and summarize the latest reports on the role of WISP-1 in obesity, insulin resistance and type 2 diabetes.

Serum betatrophin levels are significantly increased in obese patients compared to lean patients regardless to the presence of PCOS

Betatrophin, which regulates glucose metabolism, is primarily expressed in liver and fat tissue. We aimed to investigate betatrophin levels in patients with polycystic ovary syndrome (PCOS) that is the most common endocrine pathology in women of reproductive age. A total of 69 women were included in this prospective study: 35 patients with PCOS (18 obese and 17 lean) and 34 healthy controls (17 obese and 17 lean). Patients who met the criteria were compared regarding betatrophin levels and other hormonal values. Serum betatrophin level did not differ between obese PCOS patients and obese controls, and lean PCOS patients and lean controls; while significantly increased in obese PCOS patients and controls compared to lean PCOS patients and controls. Total testosterone and androstenedione were significantly higher in patients with PCOS than in controls both in the obese and lean groups, while sex hormone-binding globulin was significantly lower in patients with PCOS than in controls both in the obese and lean groups. However, remaining hormone values were similar between groups. Betatrophin level was significantly increased in obese patients compared to lean patients independent to the presence of PCOS.

Adipose Insulin Resistance and Circulating Betatrophin Levels in Women with PCOS

The role of IR and metabolic disorders has become a crucial topic of study in the pathogenesis of PCOS. Adipose tissue is an important target organ of insulin, and adipose IR plays an important role in the occurrence and development of PCOS. This study seeks to investigate the role of adipose IR in the development of PCOS and to examine its relationship with circulating betatrophin levels in women with PCOS. A cross-sectional analysis of a cohort of women with PCOS and healthy women was performed in this study. Serum betatrophin concentrations were measured by ELISA. Adipose IR was calculated using the product of fasting insulin and FFA concentrations, and the relationship between adipose IR, circulating betatrophin, and other parameters was analyzed. Adipose IR in women with PCOS was significantly higher than that in controls. We found that women with PCOS who have adipose IR (adipose IR ≥ 55) have a higher BMI and higher blood glucose, insulin, PRL, FFA, TG, HOMA-_IR, AUC_glucose, AUC_insulin, VAI_female, and BAI levels than PCOS-afflicted women without adipose IR, while M-values, and SHBG and LH levels were lower. In women with PCOS, serum betatrophin levels were significantly increased compared with controls. Adipose IR negatively correlated with M values and positively with circulating betatrophin levels in the study population. After metformin treatment, circulating betatrophin levels and adipose IR in women with PCOS were significantly decreased compared with pretreatment. Adipose IR is associated with betatrophin levels in women with PCOS. The combination of adipose IR and circulating betatrophin measurements may be significant for screening patients with PCOS.

Sick fat: the good and the bad of old and new circulating markers of adipose tissue inflammation

Adipose tissue (AT) is one of the largest endocrine organs contributing to metabolic homeostasis. The functional pleiotropism of AT depends on its ability to secrete a large number of hormones, cytokines, extracellular matrix proteins and growth factors, all influencing many local and systemic physiological and pathophysiological processes. In condition of chronic positive energy balance, adipocyte expansion, hypoxia, apoptosis and stress all lead to AT inflammation and dysfunction, and it has been demonstrated that this sick fat is a main risk factor for many metabolic disorders, such as type 2 diabetes mellitus, fatty liver, cardiovascular disease and cancer. AT dysfunction is tightly associated with aberrant secretion of bioactive peptides, the adipocytokines, and their blood concentrations often reflect the expression in the AT. Despite the existence of an association between AT dysfunction and systemic pro-inflammatory state, most of the circulating molecules detectable in obese and dysmetabolic individuals do not identify specifically the condition of sick fat. Based on this premise, this review provides a concise overview of "classic" and novel promising adipocytokines associated with AT inflammation and discusses possible critical approaches to their interpretation in clinical practice.

Decreased circulating levels of ANGPTL8 in Graves' disease patients

BACKGROUND

Angiopoietin-like protein 8 (ANGPTL8), a newly identified hormone, has been recently characterized as a metabolic regulator which can affect energy homeostasis and has interesting potentials as a metabolic disease therapy. However, little is as yet known as to whether circulating ANGPTL8 levels are altered in thyroid dysfunction. This study measured serum ANGPTL8 levels in patients with Graves' disease and explored the correlations between its serum levels and thyroid index in Graves' disease.

METHODS

The concentration of ANGPTL8 was analyzed in blood samples of 128 well-characterized individuals whose anthropometric parameters, biochemical parameters, and thyroid index were measured. The participants were divided into Graves' disease patients (n = 60) and healthy control subjects (n = 68). Logistic regression was used to evaluate the relationship between ANGPTL8 and Graves' disease.

RESULTS

Serum ANGPTL8 levels were more significantly decreased in Graves' disease patients than in healthy control subjects (177.67 ± 135.07 vs 326.41 ± 194.72 pg/mL; p < 0.001). Serum ANGPTL8 was negatively correlated with free triiodothyronine (FT3), free thyroxine (FT4), and thyroid peroxidase antibodies (TPOAb) while being positively correlated with thyrotropin (TSH). Logistic regression analyses demonstrated that serum ANGPTL8 was significantly associated with Graves' disease (p < 0.05).

CONCLUSIONS

Circulating concentrations of ANGPTL8 showed a significant reduction in Graves' disease patients. Thus, it is suggested that thyroid function should be taken into consideration when evaluating the results of ANGPTL8.

Serum betatrophin levels are reduced in patients with full-blown polycystic ovary syndrome

Betatrophin is defined as a new marker in glucose homeostasis and lipid metabolism. We aimed to investigate the role of serum betatrophin in full-blown polycystic ovary syndrome (PCOS) patients and 47-aged healthy women, 51 full-blown PCOS patients were included in this cross-sectional study. Betatrophin concentrations were significantly lower in PCOS group and displayed a positive correlation only with serum tryglyceride in control group (p < .05). A cutoff level (464.5 ng/L) was determined for betatrophin according to Receiver Operating Characteristic curve. Using this value, 64.7% of PCOS patients were classified as below the cutoff and in this group betatrophin was found to correlate negatively with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (p = .038, p = .020, and p = .014, respectively), and positively with total testosterone (p = .041). In the rest of PCOS cases (35.3%) who had betatrophin higher than cutoff, positive correlation was found with low-density lipoprotein cholesterol (p = .009). In conclusion, betatrophin levels are reduced in full-blown PCOS patients who had worse metabolic phenotype.

Circulating Angiopoietin-like 8 protein (ANGPTL8/Betatrophin) in patients with polycystic ovary syndrome: a systematic review and multi effect size meta-analysis

The association between circulating betatrophin levels and polycystic ovary syndrome (PCOS) is controversial and the studies in the literature are inconsistent. The aim of our study was to systematically review and meta-analyze all available literature comparing circulating betatrophin levels between human PCOS patients and controls. Relevant studies were retrieved by online database and manual searching. A total of 11 studies were included in this meta-analysis. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were obtained by a random-effects meta-analysis. Meta-analysis of correlations was performed for the associations of betatrophin with anthropometric, lipid and hormonal covariates in PCOS patients. The results indicated that the betatrophin levels were significantly elevated in PCOS patients as compared to non-PCOS controls (SMD = 0.73, 95% CI = 0.22-1.24, Z = 2.83, p = .005). A one-study leave-out sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the robustness of this meta-analysis. Our sub-group analysis indicated that this increase in betatrophin concentrations was regardless of normo-weight or obese body mass index (BMI) and insulin resistance might have an important role. There were significant positive correlations of betatrophin with age, free androgen index and free-testosterone in PCOS patients. In summary, regardless of BMI, the circulatory betatrophin levels are elevated in PCOS patients compared to controls. PCOS patients with higher insulin resistance had substantially higher circulating betatrophin concentrations.

Association of serum betatrophin with fibroblast growth factor-21 in women with polycystic ovary syndrome

PURPOSE

Betatrophin and fibroblast growth factor-21 (FGF-21), which are recently discovered members of hepatokine/adipokine family, have been proposed to be associated with some metabolic disorders in which insulin resistance plays a major role.

METHODS

We aimed to investigate serum betatrophin and FGF-21 concentrations in women with polycystic ovary syndrome (PCOS). In this cross-sectional study, we recruited 31 women with PCOS and 34 women as healthy controls. Serum betatrophin level and its relationship with serum FGF-21 level as well as metabolic parameters were examined.

RESULTS

Serum betatrophin level was significantly higher in women with PCOS‏ than the control group [1.10 (0.20-4.20) vs 0.70 (0.20-3.50) ng/ml, p = 0.004], whereas FGF-21 did not differ between the groups [74.80 (7.80-435.90) vs 119.30 (10.50-443.40) pg/ml, p = 0.13]. Serum betatrophin correlated positively with LH levels (r = 0.26, p = 0.03). After controlling BMI, there was a significant positive correlation between betatrophin and FGF-21 (r = 0.25, p = 0.04). Multivariate regression analysis revealed that FGF-21 and presence of PCOS were the significant predictors of betatrophin concentrations (R² = 0.22, F = 2.56, p = 0.03).

CONCLUSIONS

Our results indicate that betatrophin levels are increased and associated with LH and FGF-21 levels, but not with insulin resistance, in women with PCOS.

Assessment of circulating betatrophin levels in intrahepatic cholestasis of pregnancy

Objective: To investigate maternal serum levels of betatrophin and their relationship with total bile acid (TBA) levels in patients with intrahepatic cholestasis of pregnancy (ICP).Materials and methods: Fifty-nine pregnant women with ICP (31 patients with severe and 28 patients with mild disease classifications) and 23 healthy women with uncomplicated pregnancies as the control group included the study. The maternal betatrophin, fasting blood glucose, fasting insulin (FI), and homeostatic model assessment of insulin resistance (HOMA-IR) levels of the groups were compared.Results: Serum betatrophin levels were significantly higher in the ICP groups than in the control group (p = .04 and p < .001, respectively). The FI levels and HOMA-IR values were significantly higher in the severe ICP group than in the control group (p = .006 and p = .001, respectively). While a significant positive correlation was found between betatrophin levels and fasting and postprandial TBA levels, there was no significant correlation among betatrophin and HOMA-IR or FI levels.Conclusions: Betatrophin levels were shown to correlate with TBA levels, it provides a model for future studies to understand the physiopathology of ICP, a complex metabolic disease. Changes in betatrophin levels may shed light on the pathogenesis of ICP.

MANAGEMENT OF ENDOCRINE DISEASE: Polycystic ovary syndrome and nonalcoholic fatty liver disease

Polycystic ovary syndrome (PCOS) is a frequent endocrine disease in women, with a number of metabolic and reproductive consequences. Obesity, insulin resistance (IR) and type 2 diabetes are prominent metabolic characteristics of PCOS and common factors affecting liver function and generating nonalcoholic fatty liver disease (NAFLD). Multiple genes involved in the synthesis of androgens, cytokines and IR, as well as acquired factors, such as endocrine disruptors, could associate the etiopathogenesis of PCOS and NAFLD. Besides the high prevalence of PCOS in general population, NAFLD was shown to be a frequent condition in transition periods, such as adolescence and menopause. Although liver biopsy is considered to be the gold standard for diagnosing liver damage, its routine use in such a prevalent condition as PCOS can be related to a higher rate of complications. Therefore, it is necessary to be able to diagnose NAFLD using simple and reliable surrogate markers. Recently, fatty liver index and NAFLD fatty liver score analyzed in large cohorts of PCOS women have been shown as accurate markers of liver damage in this metabolically vulnerable population. Lifestyle changes are still the mainstay of the management of NAFLD in PCOS, although prospective randomized controlled clinical studies remain a priority in the field. With regard to medications, metformin may be the drug of choice for treating PCOS patients with NAFLD when pharmacologic therapy is considered. Liraglutide use in obese PCOS has shown favorable effects on the predictors of liver fibrosis. In this review, we aim to summarize the influence of the common risk factors and to discuss the diagnostic approaches and management options for NAFLD in patients with PCOS.

Serum Concentrations of Betatrophin and Its Association with Indirect Indices of Insulin Resistance and Beta Cell Function in Women with Polycystic Ovary Syndrome

INTRODUCTION

Data underline the role of betatrophin in glucose homeostasis. Polycystic ovary syndrome (PCOS) is characterized by insulin resistance (IR). The aim of our study was to investigate the relationship of serum betatrophin concentrations with indirect indices of IR and insulin secretion in women with PCOS, compared to the control group.

METHODS

The study group comprised 43 women with PCOS and 16 controls. IR was assessed by HOMA-IR and Matsuda index. Insulin secretion was evaluated with HOMA-B. An oral glucose tolerance test (OGTT) with estimation of serum betatrophin concentrations was performed.

RESULTS

Glucose load resulted in an increase in serum betatrophin concentrations in the control group (p = 0.02). Serum betatrophin concentrations at 120 min of OGTT were lower in women with PCOS than in the control group (p = 0.02). We observed positive correlations between baseline serum betatrophin concentrations and HOMA-IR (r = 0.39, p = 0.008), negative correlations with Matsuda index (r = -0.31, p = 0.004), and a positive relationship with HOMA-B (r = 0.38, p = 0.01) in women with PCOS. Multiple regression analysis revealed that HOMA-B (β = 0.47, p = 0.001) was an independent factor connected to serum betatrophin levels in PCOS.

CONCLUSIONS

Serum concentrations of betatrophin are connected with insulin resistance and beta cell function and did not change after glucose load in women with PCOS.