Dysregulation of glucose metabolism even in Chinese PCOS women with normal glucose tolerance

Metformin versus metformin plus pioglitazone on gonadal and metabolic profiles in normal-weight women with polycystic ovary syndrome: a single-center, open-labeled prospective randomized controlled trial

OBJECTIVE

To investigate the effects of metformin (MET) monotherapy and pioglitazone plus MET (PIOMET) therapy on gonadal and metabolic profiles in normal-weight women with polycystic ovary syndrome (PCOS).

METHODS

Sixty normal-weight women with PCOS were recruited between January and September 2022 at the Shengjing Hospital of China Medical University. They were randomly assigned to the MET or PIOMET groups for 12 weeks of MET monotherapy or PIOMET therapy. Anthropometric measurements, menstrual cycle changes, gonadal profiles, and the oral glucose insulin-releasing test (OGIRT) were performed at baseline and after the 12-week treatment.

RESULTS

Thirty-six participants completed the trial. MET and PIOMET therapies improved menstrual cycles after the 4- and 12-week treatments; however, there was no statistical difference between the two groups. PIOMET therapy improved luteinizing hormone (LH), luteinizing hormone/follicle stimulating hormone (LH/FSH) ratio, and free androgen index (FAI) levels after the 4-week treatment, whereas MET monotherapy only improved total testosterone (TT) levels compared to baseline (P < 0.05). Both MET and PIOMET therapies improved TT and anti-Mullerian hormone (AMH) levels after the 12-week treatment (P < 0.05). In addition, only PIOMET therapy significantly improved sex hormone-binding globulin (SHBG), FAI, and androstenedione (AND) levels than the baseline (P < 0.05). PIOMET therapy improved SHBG and AMH levels more effectively than MET monotherapy (P < 0.05). Furthermore, PIOMET treatment was more effective in improving blood glucose levels at 120 and 180 min of OGIRT compared to MET monotherapy (P < 0.05).

CONCLUSIONS

In normal-weight women with PCOS, PIOMET treatment may have more benefits in improving SHBG, AMH, and postprandial glucose levels than MET monotherapy, and did not affect weight. However, the study findings need to be confirmed in PCOS study populations with larger sample sizes.

Single nucleotide polymorphisms in binding site of miRNA-135a and targeted gene IRS2 are correlated with multiple clinical features of PCOS: A study in Chinese women

BACKGROUND:

The etiology of polycystic ovary syndrome (PCOS) remains unclear with highly heterogeneous clinical manifestations, recently growing evidence revealing genetic variants play a crucial part in its pathogenesis.

OBJECTIVE:

This study aimed to examine the correlation between SNPs in miRNA-135a’s binding site of targeted gene IRS2 and clinical manifestations of PCOS in Chinese females.

METHOD:

A total of 126 Chinese women with PCOS and 109 healthy women were enrolled, divided into 4 groups based on different clinical features of hyperandrogenemia (HA), insulin resistance (IR), polycystic ovary morphology (PCOM) and obesity. We analyzed 2 single nucleotide polymorphisms (SNPs) of the IRS2 gene (rs2289046 and rs1865434) and clinical features’ laboratory measurements such as sex hormone, fasting plasma glucose (FPG), fasting plasma insulin (FINS).

RESULTS:

Located in miRNA-135a binding site of IRS2 gene, the rs2289046’s triple genotypes distribution showed a significant difference between PCOS/control group and PCOM/non-PCOM group (P< 0.05) while the rs1865434’s triple genotype distribution showed a significant difference between obesity/non-obesity group (P< 0.05).

CONCLUSION:

The results revealed the two SNPs as rs2289046 and rs1865434 in the IRS-2 binding region of miRNA-135a have correlations with the clinical features of PCOS in Chinese population.

Characterizing skeletal muscle dysfunction in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine condition affecting women. It has traditionally been viewed as a primarily reproductive disorder; however, it is increasingly recognized as a lifelong metabolic disease. Women with PCOS are at increased risk of insulin resistance (IR), type 2 diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular disease. Although not currently a diagnostic criterion, IR is a cardinal pathophysiological feature and highly prevalent in women with PCOS. Androgens play a bidirectional role in the pathogenesis of IR, and there is a complex interplay between IR and androgen excess in women with PCOS. Skeletal muscle has a key role in maintaining metabolic homeostasis and is also a metabolic target organ of androgen action. Skeletal muscle is the organ responsible for the majority of insulin-mediated glucose disposal. There is growing interest in the relationship between skeletal muscle, androgen excess and mitochondrial dysfunction in the pathogenesis of metabolic disease in PCOS. Molecular mechanisms underpinning defects in skeletal muscle dysfunction in PCOS remain to be elucidated, but may represent promising targets for future therapeutic intervention. In this review, we aim to explore the role of skeletal muscle in metabolism, focusing particularly on perturbations in skeletal muscle specific to PCOS as observed in recent molecular and in vivo human studies. We review the possible role of androgens in the pathophysiology of skeletal muscle abnormalities in PCOS, and identify knowledge gaps, areas for future research and potential therapeutic implications. Despite increasing interest in the area of skeletal muscle dysfunction in women with PCOS, significant challenges and unanswered questions remain, and going forward, novel innovative approaches will be required to dissect the underlying mechanisms.

Protective effects of berberine in a rat model of polycystic ovary syndrome mediated via the PI3K/AKT pathway

Background

Ber, a Chinese herbal monomer has been reported to exhibit an array of pharmacological activities related to the lowering of blood glucose and the treatment of polycystic ovarian syndrome (PCOS). In the present study, we aimed to elucidate the effect of berberine (Ber) on a rat model of PCOS mediated via the PI3K/AKT signaling pathway.

Methods

A PCOS animal model was induced with the administration of letrozole, and animals were then randomized into untreated or Ber and metformin hydrochloride treated groups. After administration, fasting blood glucose, HOMA‐IR, fasting insulin (FINS) values, and the serum hormone levels were measured in PCOS rats. The ovarian tissues were stained with hematoxylin and eosin and terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labeling (TUNEL) for pathological and apoptosis examination. Moreover, the effect of Ber on the proliferation and apoptosis of granulosa cells was detected by CCK‐8 assays and flow cytometry. The influence of Ber on granulosa cells was confirmed by blockade of the PI3K/AKT pathway. In addition, the modulatory effect of the blockade of the PI3K/AKT pathway on the expression of related proteins was demonstrated via western blotting.

Results

We found that Ber was able to restore the serum hormone levels and improve IR in a PCOS rat model. The morphological lesions and apoptosis of the ovary were also restored by the Ber treatment. Blockade of the PI3K/AKT pathway attenuated the influences of Ber on the proliferation and apoptosis of granulosa cells.

Conclusion

The beneficial effects of Ber on PCOS included alterations of the serum hormone levels, recovery of morphological lesions in the ovary, improvement of insulin resistance, and cell viability and inhibition of apoptosis, which were all mediated through the PI3K/AKT pathway.

Expression of angiopoietin-like protein 2 in ovarian tissue of rat polycystic ovarian syndrome model and its correlation study

BACKGROUND

This study investigated the expression of angiopoietin-like protein 2 (ANGPTL2) in the tissues of rat models of polycystic ovary syndrome (PCOS) and its correlation with PCOS.

METHODS

Six-weeks-old female specific pathogen-free rats (n = 60) were divided into blank control, PCOS model, and metformin groups (n = 20/group). After 21 days of metformin intervention, the serum sex hormones, fasting blood glucose, fasting insulin, and insulin resistance (IR) of rats in each group were measured. The mRNA levels of ANGPTL2, Foxol, and Akt in the ovarian tissues were monitored by real-time fluorescence quantitative PCR.

RESULTS

Compared with the control group, the levels of serum sex hormones, fasting blood glucose, fasting insulin, and IR in the model group showed significant increases, and the levels of ANGPTL2, Foxol, and Akt in the ovarian tissue also showed significant increases. Compared with the PCOS group, the serum sex hormones, fasting blood glucose, fasting insulin, and IR of rats in the metformin group were significantly decreased, and the levels of ANGPTL2, Foxol, and Akt in ovarian tissues also showed significant decreases.

CONCLUSIONS

These findings suggest that ANGPTL2 might participate in the development of PCOS through the PI3K/Akt signaling pathway. Metformin improves IR by reducing the expression of ANGPTL2, thus improving the endocrine environment of PCOS and might change the disease outcome.

Prevalence and degree of insulin resistance in Chinese Han women with PCOS: Results from euglycemic-hyperinsulinemic clamps

OBJECTIVE

The euglycemic-hyperinsulinemic clamp is the gold standard to evaluate insulin resistance (IR), but there are only a few studies on the prevalence of IR in Chinese Han women with polycystic ovary syndrome (PCOS). This study investigated: (a) the prevalence of IR in Chinese Han women with PCOS by clamp, (b) the degree of reduction in insulin sensitivity (IS) and the contribution of body mass index (BMI).

DESIGN

Retrospective cross-sectional analysis.

PATIENTS

Chinese Han women with PCOS (n = 448) visiting the Department of Endocrinology or the Department of Obstetrics and Gynaecology of the First Affiliated Hospital of Chongqing Medical University. Chinese Han women without PCOS (controls) from the same area (n = 40).

MEASUREMENTS

Clamp-measured IS, age, BMI, and total testosterone.

RESULTS

The prevalence of IR and reduction in IS were 56.3% and 30.3%, respectively, in Chinese Han women with PCOS (both P < 0.001). The inherent reduction in IS was 18.8% in lean women with PCOS and BMI independently reduced IS by 37.9% in obese women with PCOS. The prevalence of IR estimated by homeostatic model assessment (HOMA) was lower than that determined by clamp. The multivariable analysis showed that IR by clamp (R²  = 0.48, P < 0.001) was independently associated with BMI (β = -0.52, P < 0.001), waist-hip ratio (β = -0.23, P < 0.001), total testosterone (β = -0.07, P = 0.045) and age (β = 0.17, P < 0.001), while IR by HOMA was only associated with BMI (R²  = 0.25, β = 0.50, P < 0.001). There were no differences in BMI groups distribution, HOMA-IR and M values among the four PCOS subtypes (all P > 0.05).

CONCLUSIONS

56.3% of Chinese Han women with PCOS had IR and their reduction in IS was 30.3%. Obesity exacerbated the reduction in IS. When being evaluated by HOMA, the prevalence and the risk factors of IR in Chinese women with PCOS were underestimated.

Diagnosis and follow-up of type 2 diabetes in women with PCOS: a role for OGTT?

Polycystic ovary syndrome (PCOS) is common in premenopausal women. The majority of women with PCOS have insulin resistance and the risk of type 2 diabetes mellitus (T2D) is higher in women with PCOS compared to controls. In non-pregnant women with PCOS, glycemic status may be assessed by oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) or HbA1c. OGTT has been reckoned gold standard test for diagnosing T2D, but OGTT is rarely used for diagnostic purpose in other non-pregnant individuals at risk of T2D, apart from PCOS. OGTT has questionable reproducibility, and high sensitivity of the 2-h glucose value is at the expense of relatively low specificity, especially regarding impaired glucose tolerance (IGT). Furthermore, lean women with PCOS are rarely diagnosed with T2D and only few percent of normal-weight women have prediabetes. Glycemic status is necessary at diagnosis and during follow-up of PCOS, especially in women with high risk of T2D (obesity, previous gestational diabetes (GDM)). We suggest that OGTT should be used in the same situations in PCOS as in other patient groups at risk of T2D. OGTT is indicated for diagnosing GDM; however, OGTT during pregnancy may not be indicated in lean women with PCOS without other risk factors for GDM.

Assessment of insulin resistance in Chinese PCOS patients with normal glucose tolerance

The study aimed to investigate insulin resistance (IR) status in polycystic ovary syndrome (PCOS) women with normal glucose tolerance (NGT), and further to evaluate feasible diagnostic method for those patients. Three hundred and twenty-five PCOS women with NGT and ninety-five healthy age-matched controls were recruited with Rotterdam criterion and 75 g oral glucose tolerance test (OGTT). IR status was estimated following a glycemic and insulinemic OGTT (0, 30, 60, 120, and 180 min). A modified HOMA-IR formula was applied to each time-course value of glycemia and insulinemia. The predictive performance of each IR index was analyzed with the use of ROC curves. Compared with healthy controls, both non-obese and obese PCOS patients with NGT had a higher BMI, serum glucose, insulin value (p < .05). The best predictive index of IR in non-obese PCOS-NGT was a HOMA-M30 value of 20.36 or more (AUC: 0.753). In obese PCOS-NGT population, the best predictive performance was obtained by a HOMA-M60 value of 32.17 or more (AUC: 0.868). IR was common in Chinese PCOS women with NGT, and the early assessment of IR should be heeded. We recommended HOMA-M30 (Cutoff: 20.36) and HOMA-M60 (Cutoff: 32.17) as the best predictive parameters for non-obese and obese PCOS-NGT patients, respectively.

Beneficial effects of Heqi san on rat model of polycystic ovary syndrome through the PI3K/AKT pathway

BACKGROUND

Heqi San, a traditional Chinese medicine (TCM) has been reported to regulate hormone levels in patients with metabolic disease, suggesting a potential clinical application. In the current study, we aimed to elucidate the effect of Heqi San on rat model of polycystic ovary syndrome (PCOS).

METHOD

PCOS model was established in female SD rats. Rats were randomly divided into four groups: the control, untreated PCOS model, Heqi San treated PCOS model (8.1 g/kg) and metformin (MET) treated PCOS model (135 mg/kg) groups. All animals were subcutaneously injected with 6 mg/100 g dehydroepiandrosterone (DHEA) in the neck once a day for 20 consecutive days. The serum hormone levels were measured by ELISA. The ovarian tissues were stained with hematoxylin and eosin (HE) to undergo pathological examination. The expression levels of GLTU4 and PTEN mRNA were examined by real time PCR. The crucial proteins in the PI3K/APT pathway were analyzed by western blotting. Then, the functions of the target genes were analyzed using bioinformatics approaches.

RESULTS

We found that Heqi San was able to recover the serum hormone levels and improve insulin resistance in PCOS rat model. A morphological lesion of the ovary was also restored with the Heqi San treatment. More importantly, we discovered a correlation between the PI3K/AKT signaling pathway and the beneficial effects of Heqi San, demonstrating that its application could alter the expression levels of p-ERK, p-AKT, p-GSK3β, IRS-1, PTEN and GLTU4, all key factors in the PI3K/APT pathway. Through a bioinformatical analysis, we predicted the related gene function and pathway of the pathological mechanism of PCOS and found miRNAs that are likely to be critical in PCOS occurrence, including rno-miR-144-3p, rno-miR-30c-2-3p, rno-miR-486, rno-miR-3586-3p and rno-miR-146b-5p.

CONCLUSION

The beneficial effects of Heqi on PCOS, including alter serum hormone levels, recover ovary morphological lesions and improve insulin resistance, which is mediated through the PI3K/AKT pathway. The potential role of miRNA-144-3p in PCOS pathogenesis.

Insulin resistance according to β-cell function in women with polycystic ovary syndrome and normal glucose tolerance

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with insulin resistance (IR) and compensatory hyperinsulinemia. IR is recognized as a major risk factor for the development of type 2 diabetes mellitus. However, few studies have investigated IR in women with PCOS and normal glucose tolerance. The objective of this study was to evaluate IR and β-cell function in women with PCOS and normal glucose tolerance. Additionally, we sought to evaluate the usefulness of oral glucose tolerance test (OGTT)-derived IR indices in lean women with PCOS.

METHODS

We recruited 100 women with PCOS and normal glucose tolerance and 100 age- and BMI-matched women as controls. IR and insulin secretory indices, including the homeostasis-model assessment (HOMA)-IR, HOMA-M120, HOMA-F and the Stumvoll index, were calculated from an OGTT. Increased β-cell function was defined as>75th percentile for the HOMA-F in control women.

RESULTS

Women with PCOS had higher values for post-load 2-hour glucose, fasting insulin, post-load 2-hour insulin, HOMA-IR, HOMA-M120, HOMA-F and lower values for the Stumvoll index than the controls (all Ps<0.05). Women with PCOS and increased β-cell function showed lower Stumvoll index values than the matched controls (P<0.05). The HOMA-F was significantly associated with the HOMA-M120 and Stumvoll index when adjusted for age and BMI in a multiple regression analysis (all Ps<0.05). The HOMA-M120 was positively correlated with triglycerides and free testosterone, and the Stumvoll index was negatively correlated with triglycerides and free testosterone in lean women with PCOS (all Ps<0.05).

CONCLUSIONS

Women with PCOS and normal glucose tolerance showed higher IR than controls matched for age, BMI, and β-cell function. β-cell function was increased in women with PCOS when compared to the matched controls, but not when the lean subjects were compared to the matched controls separately. Therefore, early evaluation of IR in women with PCOS and normal glucose tolerance may be needed.

Association between red blood cell distribution width and polycystic ovary syndrome

AIMS

The red blood cell distribution width (RDW) is being recognized as a marker of chronic inflammation and routinely reported as part of a complete blood count (CBC) without any additional costs. High levels of RDW associate with oxidative stress and cardiovascular disease risk. We aimed to investigate the relation between the level of RDW and high-sensitive C-reactive protein (hs-CRP), HOMA-IR, BMI and body fat percentage in women with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

Cross-sectional and observational studies were conducted in 90 subjects with PCOS and 87 age- and BMI-matched controls. Body fat percentage, CBC, fasting serum glucose, serum insulin, hs-CRP, lipids, and total and free-testosterone levels were measured.

RESULTS

RDW levels were significantly higher in the PCOS group compared with the control group (12.98 ± 0.92% versus 12.59 ± 0.84%, p = 0.004). RDW levels were positively correlated with hs-CRP, HOMA-IR and BMI. Multivariate analysis showed that high-RDW levels were associated with PCOS. Subjects with the highest quartile RDW levels were nearly 2.8 times more likely to develop PCOS compared with subjects with the lowest quartile RDW. ROC curve analysis showed that RDW levels were useful as a diagnostic marker for PCOS. The optimal cut-off value for detecting PCOS was ≥12.54% (sensitivity 67% and specificity 70%).

CONCLUSIONS

RDW levels were higher in women with PCOS, and high-RDW levels were independently associated with PCOS. This link in between RDW and PCOS may be due to an underlying chronic inflammation in subjects with PCOS.

Women with polycystic ovary syndrome have intrinsic insulin resistance on euglycaemic-hyperinsulaemic clamp

STUDY QUESTION

What is the prevalence of insulin resistance (IR) and the contributions of intrinsic and extrinsic IR in women diagnosed with polycystic ovary syndrome (PCOS) according to the Rotterdam criteria?

SUMMARY ANSWER

We report novel clamp data in Rotterdam diagnosed PCOS women, using World Health Organization criteria for IR showing that women with PCOS have a high prevalence of IR, strengthening the evidence for an aetiological role of IR in both National Institutes of Health (NIH) and Rotterdam diagnosed PCOS in lean and overweight women.

WHAT IS KNOWN ALREADY

PCOS is a complex endocrine condition with a significant increased risk of gestational diabetes and type 2 diabetes.

STUDY DESIGN, SIZE, DURATION

Using a cross-sectional study design, 20 overweight and 20 lean PCOS (Rotterdam criteria), 14 overweight and 19 lean body mass index (BMI)-matched control non-PCOS women underwent clinical measures of IR after a 3-month withdrawal of insulin sensitizers and the oral contraceptive pill.

MATERIALS, SETTING, METHODS

In an academic clinic setting, glucose infusion rate (GIR) on euglycaemic-hyperinsulinaemic clamp was investigated as a marker of insulin sensitivity.

MAIN RESULTS AND THE ROLE OF CHANCE

PCOS women were more IR than BMI-matched controls (main effect for BMI and PCOS; P < 0.001). IR was present in 75% of lean PCOS, 62% of overweight controls and 95% of overweight PCOS. Lean controls (mean ± SD; GIR 339 ± 76 mg min⁻¹ m⁻²) were less IR than lean PCOS (270 ± 66 mg min⁻¹ m⁻²), overweight controls (264 ± 66 mg min⁻¹ m⁻²) and overweight PCOS (175 ± 96 mg min⁻¹ m⁻²). The negative relationship between BMI and IR reflected by GIR was more marked in PCOS (y = 445.1 - 7.7x, R² = 0.42 (P < 0.0001) than controls (y = 435.5 - 4.6x, R² = 0.04 (P < 0.01)).

LIMITATIONS, REASONS FOR CAUTION

The study did not use glucose tracer techniques to completely characterize the IR, as well as the lack of matching for body composition and age.

WIDER IMPLICATIONS OF THE FINDINGS

IR is exacerbated by increased BMI, supporting intrinsic IR in PCOS. BMI impact on IR is greater in PCOS, than in controls, irrespective of visceral fat, prioritizing lifestyle intervention and the need for effective therapeutic interventions to address intrinsic IR and prevent diabetes in this high-risk population.

STUDY FUNDING/COMPETING INTEREST(S)

This investigator-initiated trial was supported by grants from the National Health & Medical Research Council (NHMRC) Grant number 606553 (H.J.T., N.K.S. and S.K.H.) as well as Monash University and The Jean Hailes Foundation. H.J.T. is an NHMRC Research Fellow. N.K.S. is supported through the Australian Government's Collaborative Research Networks (CRN) programme. A.E.J. is a Jean Hailes and NHMRC scholarship holder. The authors declare that there is no conflict of interest associated with this manuscript.