Review of Novel Potential Insulin Resistance Biomarkers in PCOS Patients—The Debate Is Still Open

The role of asprosin in regulating ovarian granulosa- and theca-cell steroidogenesis: a review with comparisons to other adipokines

Adipose tissues produce a variety of biologically active compounds, including cytokines, growth factors and adipokines. Adipokines are important as they function as endocrine hormones that are related to various metabolic and reproductive diseases. The goal of this review was to summarise the role of asprosin, a recently discovered adipokine, and compare its role in ovarian steroidogenesis with that of other adipokines including adiponectin, leptin, resistin, apelin, visfatin, chemerin, irisin, and gremlin 1. The summary of concentrations of these adipokines in humans, rats and other animals will help researchers identify appropriate doses to test in future studies. Review of the literature indicated that asprosin increases androstenedione production in theca cells (Tc), and when cotreated with FSH increases oestradiol production in granulosa cells (Gc). In comparison, other adipokines (1) stimulate Gc oestradiol production but inhibit Tc androgen production (adiponectin), (2) inhibit Gc oestradiol production and Tc androstenedione production (leptin and chemerin), (3) inhibit Gc steroidogenesis with no effect on Tc (resistin), (4) inhibit Gc oestradiol production but stimulate Tc androgen production (gremlin 1), and (5) increase steroid secretion by Gc, with unknown effects on Tc steroidogenesis (apelin and visfatin). Irisin has direct effects on Gc but its precise role (inhibitory or stimulatory) may be species dependent and its effects on Tc will require additional research. Thus, most adipokines have direct effects (either positive or negative) on steroid production in ovarian cells, but how they all work together to create a cumulative effect or disease will require further research.

CAPN2 correlates with insulin resistance states in PCOS as evidenced by multi-dataset analysis

OBJECTIVE

IR emerges as a feature in the pathophysiology of PCOS, precipitating ovulatory anomalies and endometrial dysfunctions that contribute to the infertility challenges characteristic of this condition. Despite its clinical significance, a consensus on the precise mechanisms by which IR exacerbates PCOS is still lacking. This study aims to harness bioinformatics tools to unearth key IR-associated genes in PCOS patients, providing a platform for future therapeutic research and potential intervention strategies.

METHODS

We retrieved 4 datasets detailing PCOS from the GEO, and sourced IRGs from the MSigDB. We applied WGCNA to identify gene modules linked to insulin resistance, utilizing IR scores as a phenotypic marker. Gene refinement was executed through the LASSO, SVM, and Boruta feature selection algorithms. qPCR was carried out on selected samples to confirm findings. We predicted both miRNA and lncRNA targets using the ENCORI database, which facilitated the construction of a ceRNA network. Lastly, a drug-target network was derived from the CTD.

RESULTS

Thirteen genes related to insulin resistance in PCOS were identified via WGCNA analysis. LASSO, SVM, and Boruta algorithms further isolated CAPN2 as a notably upregulated gene, corroborated by biological verification. The ceRNA network involving lncRNA XIST and hsa-miR-433-3p indicated a possible regulatory link with CAPN2, supported by ENCORI database. Drug prediction analysis uncovered seven pharmacological agents, most being significant regulators of the endocrine system, as potential candidates for addressing insulin resistance in PCOS.

CONCLUSIONS

This study highlights the pivotal role of CAPN2 in insulin resistance within the context of PCOS, emphasizing its importance as both a critical biomarker and a potential therapeutic target. By identifying CAPN2, our research contributes to the expanding evidence surrounding the CAPN family, particularly CAPN10, in insulin resistance studies beyond PCOS. This work enriches our understanding of the mechanisms underlying insulin resistance, offering insights that bridge gaps in the current scientific landscape.

Protective effects of vanillic acid on letrozole-induced polycystic ovarian syndrome: A comprehensive study in female wistar rats

Background

Polycystic ovarian syndrome (PCOS) is one of the known causes of anovulatory fertility in the world. Previous research has linked oxidative stress could contribute to PCOS, and vanillic acid has shown antioxidant potential. Hence, the present study evaluated the effect of vanillic acid on letrozole-induced polycystic ovarian syndrome in female rats.

Materials and methods

PCOS was induced in Wistar female rats with letrozole (1 mg/kg, orally) in carboxymethoxycellulose (1 % w/v), administered for 21 days. After induction, the standard group received clomiphene citrate (1 mg/kg, orally) while other treatment groups were administered with vanillic acid at doses 25, 50, and 100 mg/kg, orally for 15 days, and without treatment was considered a negative control group. Different parameters studied were body weight, ovary weight, blood glucose, lipid profile, hormonal levels [luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone], markers for oxidative stress (superoxide dismutase, reduced glutathione, catalase, and malonaldehyde), and histopathology of the ovary. Statistical analysis was done for the results and p < 0.05 was considered to indicate the significance.

Results

Vanillic acid-treated animals showed a concentration-dependent activity on the tested parameters. The highest tested dose (100 mg/kg) produced a more prominent effect in significantly (P < 0.001) decreasing the body weight, and ovary weight and improving the hormonal imbalance. Also, vanillic acid significantly (P < 0.01) reduced elevated blood sugar and lipid levels. Additionally, vanillic acid reduced oxidative stress significantly (P < 0.001) in the ovaries of female rats. Histopathological reports showed a reduction in cystic follicles and appearance of normal healthy follicles at different stages of development after the administration of vanillic acid. Furthermore, these effects were observed to be comparable with those recorded for standard drug, clomiphene.

Conclusion

The current study data suggests that vanillic acid has protected the letrozole-induced polycystic ovarian syndrome. In the event of several side effects associated with conventional treatments used for PCOS, the findings of this study suggest the promising role of vanillic acid. More research in this direction might identify the true potency of vanillic acid in the treatment of PCOS.

Blood nesfatin-1 levels in patients with polycystic ovary syndrome: a systematic review and meta-analysis

Background

Previous studies have investigated the relationship between nesfatin-1 level and polycystic ovary syndrome (PCOS). However, these studies have produced conflicting results. Thus, in this meta-analysis, we aimed to clarify the association between blood nesfatin-1 levels and PCOS, and the ability of nesfatin-1 as a biomarker in PCOS.

Methods

Meta-analysis was performed using STATA 12.0 software. We computed standard mean difference (SMD) and 95% confidence interval (CI) regarding the comparison of blood nesfatin-1 in patients with PCOS and controls.

Results

The present meta-analysis showed no significant difference in blood nesfatin-1 level between patients with PCOS and controls with a random effects model (SMD = 0.03; 95%CI: -0.71, 0.77; I2 = 97.1%, p value for Q test < 0.001). Subgroup analysis for different ethnicities reported no significant difference in blood nesfatin-1 level between patients with PCOS and controls in both Caucasian and Asian populations. Subgroup analysis for different sample types reported no significant difference in serum nesfatin-1 level between patients with PCOS and controls. Subgroup studies reported no significant difference in blood nesfatin-1 level between PCOS and controls in both obese and non-obese populations.

Conclusion

In conclusion, there is no significant relationship between blood nesfatin-1 levels and PCOS.

Gremlin-1 in pregnancy and postpartum: relation to the fatty liver index, markers of bone health, glucose metabolism and gestational diabetes mellitus status

INTRODUCTION

Gremlin-1 is a peptide that functions as an antagonist to bone morphogenic proteins and is overexpressed in obesity and type 2 diabetes mellitus. Gremlin-1 has not yet been investigated in pregnancy, pregnancy-related insulin resistance or gestational diabetes mellitus (GDM).

PATIENTS AND METHODS

Gremlin-1 levels were measured throughout the pregnancy of 58 women at high risk for GDM at the Medical University of Vienna. Furthermore, an oral glucose tolerance test, fasting insulin, fasting glucose, sex hormones, blood lipids, liver and renal parameters, and markers of bone development were evaluated at two points during pregnancy (< 20 weeks of gestation (GW), GW 24-28) and 12-14 weeks postpartum.

RESULTS

Gremlin-1 levels decreased from < 20 GW (mean = 9.2 pg/ml, SD = 8.4 pg/ml) to GW 24-28 (mean = 6.7 pg/ml, SD = 5.7 pg/ml, p = 0.033) and increased again postpartum, albeit not significantly (mean = 10.7 pg/ml, SD = 13.1 pg/ml, p = 0.339). During pregnancy, Gremlin-1 levels correlated negatively with osteocalcin and procollagen type I aminoterminal propeptide (P1NP), markers of bone health. Concerning glucose metabolism, Gremlin-1 levels were inversely related to the Insulinogenic Index at GW < 20. However, Gremlin-1 levels were not significantly different between women with normal glucose tolerance and GDM during pregnancy. Postpartum, Gremlin-1 was associated with the fatty liver index, osteocalcin levels, diastolic blood pressure and weight.

CONCLUSION

Gremlin-1 levels decreased significantly during pregnancy. The biomarker is not related to GDM status, but correlates negatively with the Insulinogenic Index, an index related to beta cell function. Trial Registry Number ACTRN12616000924459.

Spexin role in human granulosa cells physiology and PCOS: expression and negative impact on steroidogenesis and proliferation†

Spexin (SPX) is a novel neuropeptide and adipokine negatively correlated with obesity and insulin resistance. A recent study investigated expression and regulatory function of SPX in the hypothalamus and pituitary; however, the effect on ovarian function is still unknown. The aim of this study was to characterize the expression of SPX and its receptors, galanin receptors 2 and 3 (GALR2/3), in the human ovary and to study its in vitro effect on granulosa cells (GC) function. Follicular fluid (FF) and GC were obtained from normal weight and obese healthy and diagnosed with polycystic ovarian syndrome (PCOS) women. Expression of SPX and GALR2/3 in the ovary was studied by qPCR, western blot, and immunohistochemistry. The level of SPX in FF was assessed by enzyme-linked immunosorbent assay. The in vitro effect of recombinant human SPX on GC proliferation, steroidogenesis, and signaling pathways (MAP3/1, STAT3, AKT, PKA) was analyzed. Moreover, GC proliferation and estradiol (E2) secretion were measured with and without an siRNA against GALR2/3 and pharmacological inhibition of the above kinases. The results showed that both the SPX concentration in FF and its gene expression were decreased in GC of obese and PCOS women, while the protein expression of GALR2/3 was increased. We noted that SPX reduced GC proliferation and steroidogenesis; these effects were mediated by GALR2/3 and kinases MAP3/1, AKT, and STAT3 for proliferation or kinases MAP3/1 and PKA for E2 secretion. The obtained data clearly documented that SPX is a novel regulator of human ovarian physiology and possibly plays a role in PCOS pathogenesis.

Insulin resistance in non-diabetic hypothyroid patients: a critical examination of METS-IR as a diagnostic marker

OBJECTIVES

Insulin resistance (IR) is a significant metabolic disturbance that plays a pivotal role in various health conditions, including hypothyroidism. Homeostatic Model Assessment For Insulin Resistance (HOMA-IR) is widely used for assessing IR. However, alternative indices, such as the Metabolic Score for Insulin Resistance (METS-IR), have been developed for diverse applications. This study aimed to meticulously investigate IR in patients with hypothyroidism and to compare the effectiveness of METS-IR with HOMA-IR. To enrich our analyses, additional metrics, including the Triglyceride Glucose (TyG) Index, the Triglyceride to High-Density Lipoprotein Cholesterol Ratio (TG/HDL-C), and the Quantitative Insulin Sensitivity Check Index (QUICKI) have been incorporated.

METHODS

This cross-sectional study included 260 non-diabetic adults, 130 with hypothyroidism (case group), and 130 healthy volunteers (control group). Parameters, including Thyroid-Stimulating Hormone (TSH), free thyroxine (T4), fasting blood glucose, HbA1c, insulin levels, and lipid profiles, were measured. IR indices were calculated.

RESULTS

The groups were matched for age and gender (p = .143; p = .099). The case group demonstrated a notably elevated mean METS-IR of 195.58, in contrast to the control group's mean METS-IR of 131.10 (p = .044). The mean HOMA-IR was significantly higher in the case group than in the control group, with average of 2.00 and 1.81, respectively (p = .027). METS-IR was positively correlated with TyG (r = 0.505, p = .001) and TG/HDL-C (r = 0.844, p = .001). Meanwhile, the relationships between METS-IR, HOMA-IR, and QUICKI were significant at r = 0.194 (p = .027) and r = .210 (p = .016), respectively. METS-IR was significantly higher in patients with overt hypothyroidism (p = .016).

CONCLUSION

This study emphasizes the efficacy of METS-IR as a diagnostic tool for IR in patients with hypothyroidism, establishing it as a proficient alternative to HOMA-IR. These findings were substantiated by the correlations observed with the TyG, TG/HDL-C, and QUICKI measurements. Variations in METS-IR between individuals with subclinical and overt hypothyroidism accentuate its effectiveness in identifying metabolic abnormalities in hypothyroid conditions.

Preptin: A New Bone Metabolic Parameter?

Preptin is a 34-aminoacid peptide derived from the E-peptide of pro-insulin-like growth factor 2 (pro-IGF2) that is co-secreted with insulin and upregulates glucose-mediated insulin secretion. High serum preptin levels were described in conditions associated with insulin resistance, such as polycystic ovary syndrome and type 2 diabetes mellitus (T2M). Insulin and also IGF2 are known to be anabolic bone hormones. The "sweet bone" in T2M usually associates increased density, but altered microarchitecture. Therefore, preptin was proposed to be one of the energy regulatory hormones that positively impacts bone health. Experimental data demonstrate a beneficial impact of preptin upon the osteoblasts. Preptin also appears to regulate osteocalcin secretion, which in turn regulates insulin sensitivity. Preptin is greatly influenced by the glucose tolerance status and the level of physical exercise, both influencing the bone mass. Clinical studies describe low serum preptin concentrations in osteoporosis in both men and women, therefore opening the way towards considering preptin a potential bone anabolic therapy. The current review addresses the relationship between preptin and bone mass and metabolism in the experimental and clinical setting, also considering the effects of preptin on carbohydrate metabolism and the pancreatic-bone loop.

Circulating serum preptin levels in women with polycystic ovary syndrome: A systematic review and meta-analysis

Background

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder with complex pathogenesis and metabolic complications, such as insulin resistance. Among the new markers, preptin seems to play a significant role in metabolic disorders.

Objective

This meta-analysis was conducted to determine the relationship between circulating preptin levels and PCOS.

Materials and Methods

A systematic review and meta-analysis was performed to identify relevant articles in electronic databases such as PubMed, Web of Science, Scopus, Cochrane, EMBASE, and the Google Scholar search engine, using a predefined search strategy. A random-effects model was used to combine standard mean difference (SMD) and 95% CI to compare results between groups. Meta-regression and subgroup analysis were also performed to reveal the sources of heterogeneity.

Results

The meta-analysis encompassed a total of 8 studies and 582 participants. The results indicate a statistically significant association between PCOS and serum preptin levels, with a pooled standardized mean difference (SMD = 1.35; 95% CI]: 0.63-2.08; p < 0.001). Further analysis suggested a significant difference in serum preptin levels between women with PCOS and higher homeostatic model assessment for insulin resistance ratio (SMD = 2.40; 95% CI: 1.17-3.63; p < 0.001) within the subgroup.

Conclusion

Our meta-analysis shows that increased serum preptin levels are associated with PCOS, suggesting that preptin may be related to the pathogenesis of PCOS and may be recognized as a novel diagnostic biomarker for PCOS. However, further studies are needed to confirm our results.

Clinico-Metabolic Profile in Lean Versus Obese Polycystic Ovarian Syndrome Women

Background Polycystic ovarian syndrome (PCOS), which affects women of reproductive age, is the most prevalent endocrine disorder. Signs of excessive androgen, irregular menses, prolonged anovulation, and infertility are characteristics of the clinical phenotype. Women with PCOS are more likely to have diabetes, obesity, dyslipidemia, hypertension, anxiety, and depression. PCOS affects women's health starting before conception and continuing through their post-menopausal years. Methods Ninety-six study subjects were recruited from women visiting the gynaecology clinic according to the Rotterdam criteria for PCOS. Study subjects were then divided into lean and obese groups according to their body mass index (BMI). Demographic data, and obstetrical and gynaecological history were obtained including marital status, menstrual cycle regularity, recent abnormal weight gain (in the preceding six months), and subfertility. To identify any clinical signs of hyperandrogenism such as acne, acanthosis nigricans, or hirsutism, a general and systemic examination was conducted. Data were analyzed after the clinico-metabolic profile was assessed, compared, and contrasted between the two groups. Results The findings showed a significant correlation between obese women with PCOS and the clinical profile of PCOS i.e. menstrual irregularities, acne vulgaris, acanthosis nigricans and hirsutism; the waist-hip ratio was higher in both groups. Higher levels of fasting insulin, fasting glucose: insulin ratio, postprandial sugars, homeostasis model assessment of insulin resistance (HOMA-IR) index, total testosterone, free testosterone, and luteinizing hormone/follicle-stimulating hormone (LH: FSH) ratio were seen in obese women with PCOS, whereas the levels of fasting glucose, serum triglycerides, serum high-density lipoprotein cholesterol (HDL) were higher in all the study subjects irrespective of BMI. Conclusion The study showed that women with PCOS have a deranged metabolic profile like abnormal blood sugar, insulin resistance (IR), and hyperandrogenemia with clinical derangements like irregular menses, subfertility, and recent weight gain more frequently with higher BMI.

Polycystic Ovarian Syndrome (PCOS): Does the Challenge End at Conception?

Polycystic ovary syndrome (PCOS) is a prevalent condition that not only has the potential to impede conception but also represents the most common endocrine dysfunction in fertile women. It is considered a heterogeneous and multifaceted disorder, with multiple reproductive and metabolic phenotypes which differently affect the early- and long-term syndrome's risks. Undoubtedly, the impact of PCOS on infertility has attracted most of the attention of healthcare providers and investigators. However, there is growing evidence that even after conception is achieved, PCOS predisposes the parturient to several adverse pregnancy outcomes including a high risk of pregnancy-induced hypertension, spontaneous abortion, gestational diabetes, preeclampsia, and preterm birth, which increase the risks of stillbirth and neonatal death. Fetal growth abnormalities may also be more common, but the relationship is less well defined. This narrative review aims to summarize current knowledge regarding these conditions as they interplay with PCOS and concludes that although there appears to be an increase in these complications during the pregnancy of women with PCOS, there is a need for further research to clarify the possible confounding impact of obesity. Implications for clinical practice and future research are outlined.

Insulin Resistance in Polycystic Ovarian Syndrome

Polycystic ovarian syndrome (PCOS) is one of the readily recognised endocrine gland illnesses in women, with an incidence range from 2.2% to 26% in India. Patients experiencing PCOS experience issues involving irregular menstrual periods, hirsutism, acne, being overweight, and impotence. Long-term, low-grade inflammation has emerged as a crucial factor leading to PCOS. A rise in glucose levels may stimulate oxidative stress and a troubling reaction from mononuclear cells (MNC) of females with PCOS, which normally do not rely on fat. This is required because MNC-derived macrophages are the major source of cytokine synthesis in big adipose tissue and similarly encourage adipocyte cytokine production. In summary, data reveal the substantial risks of insulin resistance in obese people who are suffering from PCOS. The findings of this specific lesson indicated that individuals with the conventional PCOS phenotype had obesity and higher insulin levels and insulin resistance, neglecting the absence of BMI differences from other phenotypes. These data show that insulin resistance is the most significant pathophysiological trait in people with PCOS.