Metabolic comparison of polycystic ovarian syndrome and control women in Middle Eastern and UK Caucasian populations

Polycystic ovarian syndrome and miscarriage in IVF: systematic revision of the literature and meta-analysis

PURPOSE

To evaluate the risk of miscarriage in IVF cycles in women with PCOS.

METHODS

Systematic review and meta-analysis. Systematic search of MEDLINE, EMBASE and Google Scholar. The language search was restricted to English, Spanish and French, from 2000 to 2019, with crosschecking of references from relevant articles. Inclusion criteria were: (1) IVF cycles (2) a group of patients with PCOS was considered separately, (3) the miscarriage rate was reported, (4) there was a control group, (5) definition of PCOS according the Rotterdam criteria. Exclusion criteria were been excluded from the meta-analysis: (1) publication prior to the year 2000, (2) animal studies, (3) reviews, (4) abstracts or conference papers, (5) letters, (6) case reports, (7) studies comparing different IVF techniques, (8) studies comparing groups with and without metformin or other treatments, (9) studies on induced abortions. Risk of bias was assessed by the Newcastle-Ottawa score (NOS). All the included studies had a low risk of bias (NOS scores ranging 7-8). The review protocol was registered in PROSPERO (CRD42020186713). Seventeen studies were included in the meta-analysis. There was a total of 10,472 pregnancies (2650 in PCOS and 7822 in controls) of which 1885 were miscarriages (682 in PCOS and 1203 in controls). We considered the miscarriage rate (MR), preclinical MR, early MR, and late MR.

RESULTS

In IVF pregnancies the risk of miscarriage was significantly increased when considering miscarriages in total (RR = 1.59; CI = 1.45-1.75), preclinical miscarriages (RR = 1.59; CI = 1.35-1.88), and early miscarriages (RR = 1.44; CI = 1.16-1.79). The increased miscarriage rate persisted in Chinese and Western populations when considered separately. The risk of miscarriage was increased in the subgroup of fresh transfers (RR = 1.21; CI = 1.06-1.39) as well as in the subgroup including either fresh or frozen transfers (RR = 1.95; CI = 1.72-2.22).

CONCLUSION

PCOS is linked to an increased MR in IVF pregnancies both of miscarriages in total, and to an increase in preclinical and early miscarriages.

PROSPERO NUMBER

CRD42020186713.

Oxidative Stress Markers and Heat Shock Proteins in Non-Obese Women with Polycystic Ovary Syndrome Are Not Elevated and Show No Correlation with Vitamin D

INTRODUCTION

Oxidative stress (OS) is recognized in the pathophysiology of polycystic ovary syndrome (PCOS). OS results in intracellular reactive oxygen species generation, causing oxidative protein damage that is protected by heat shock proteins (HSPs). Vitamin D is thought to reduce and protect against OS; therefore, OS, HSP, and vitamin D levels may be associated with PCOS. However, their expression in PCOS without underlying inflammation is unknown.

METHODS

In this exploratory study, the plasma levels of 7 OS proteins and 10 HSPs that are affected by the OS process were measured using Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurements in non-obese, non-insulin resistant women with PCOS (n = 24) without systemic inflammation and control (n = 24) women; the cohorts were matched for weight and age. The OS proteins and HSPs were correlated with 25-hydroxy vitamin D₃ (25(OH)D₃) and the active form, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), as measured by isotope-dilution liquid chromatography tandem mass spectrometry.

RESULTS

The PCOS women versus the controls had comparable insulin resistance and systemic inflammation (C-reactive protein 2.0 mg/L vs. 2.3 mg/L, p > 0.05), but higher free androgen index and anti-mullerian hormone levels. Among the OS proteins, only esterase D (ESD; p < 0.01) was elevated in PCOS and the HSPs did not differ between the PCOS and control women. There was no correlation of 25(OH)D₃ or 1,25(OH)₂D₃ with any of the proteins.

CONCLUSIONS

In a PCOS population that was non-obese and without insulin resistance and systemic inflammation, only ESD was elevated in PCOS, whilst the other OS proteins and HSPs were not elevated. Further, none of the OS proteins or HSPs were correlated with either 25(OH)D₃ or 1,25(OH)₂D₃ in either cohort of women or when both cohorts were combined, indicating that the OS and HSP responses were largely absent and not affected by vitamin D in a non-obese PCOS population.

The Role of Heat Shock Proteins in the Pathogenesis of Polycystic Ovarian Syndrome: A Review of the Literature

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and post-menopausal women. PCOS is a multifactorial heterogeneous disorder associated with a variety of etiologies, outcomes, and clinical manifestations. However, the pathophysiology of PCOS is still unclear. Heat shock proteins (HSPs) have recently been investigated for their role in the pathogenesis of PCOS. HSPs are a class of proteins that act as molecular chaperones and maintain cellular proteostasis. More recently, their actions beyond that of molecular chaperones have highlighted their pathogenic role in several diseases. In PCOS, different HSP family members show abnormal expression that affects the proliferation and apoptotic rates of ovarian cells as well as immunological processes. HSP dysregulation in the ovaries of PCOS subjects leads to a proliferation/apoptosis imbalance that mechanistically impacts follicle stage development, resulting in polycystic ovaries. Moreover, HSPs may play a role in the pathogenesis of PCOS-associated conditions. Recent studies on HSP activity during therapeutic interventions for PCOS suggest that modulating HSP activity may lead to novel treatment strategies. In this review, we summarize what is currently known regarding the role of HSPs in the pathogenesis of PCOS and their potential role in the treatment of PCOS, and we outline areas for future research.

Components of the Complement Cascade Differ in Polycystic Ovary Syndrome

Complement pathway proteins are reported to be increased in polycystic ovary syndrome (PCOS) and may be affected by obesity and insulin resistance. To investigate this, a proteomic analysis of the complement system was undertaken, including inhibitory proteins. In this cohort study, plasma was collected from 234 women (137 with PCOS and 97 controls). SOMALogic proteomic analysis was undertaken for the following complement system proteins: C1q, C1r, C2, C3, C3a, iC3b, C3b, C3d, C3adesArg, C4, C4a, C4b, C5, C5a, C5b-6 complex, C8, properdin, factor B, factor D, factor H, factor I, mannose-binding protein C (MBL), complement decay-accelerating factor (DAF) and complement factor H-related protein 5 (CFHR5). The alternative pathway of the complement system was primarily overexpressed in PCOS, with increased C3 (p < 0.05), properdin and factor B (p < 0.01). In addition, inhibition of this pathway was also seen in PCOS, with an increase in CFHR5, factor H and factor I (p < 0.01). Downstream complement factors iC3b and C3d, associated with an enhanced B cell response, and C5a, associated with an inflammatory cytokine release, were increased (p < 0.01). Hyperandrogenemia correlated positively with properdin and iC3b, whilst insulin resistance (HOMA-IR) correlated with iC3b and factor H (p < 0.05) in PCOS. BMI correlated positively with C3d, factor B, factor D, factor I, CFHR5 and C5a (p < 0.05). This comprehensive evaluation of the complement system in PCOS revealed the upregulation of components of the complement system, which appears to be offset by the concurrent upregulation of its inhibitors, with these changes accounted for in part by BMI, hyperandrogenemia and insulin resistance.

Inflammatory Markers in Non-Obese Women with Polycystic Ovary Syndrome Are Not Elevated and Show No Correlation with Vitamin D Metabolites

Introduction. Chronic low-grade inflammation is a characteristic of women with polycystic ovary syndrome (PCOS), although this may be obesity-driven rather than an intrinsic facet of PCOS; furthermore, vitamin D deficiency, another common feature of PCOS, is reported to have an association with increased inflammation. Therefore, circulating inflammatory protein levels and circulating levels of vitamin D may be linked in PCOS, though it is unclear which vitamin D metabolites may be important. Methods. We measured plasma levels of 24 inflammatory proteins and 12 matrix metalloproteinases (proteins modulated by the inflammatory process) by slow off-rate modified aptamer (SOMA)-scan plasma protein measurement in weight and aged-matched non-obese non-insulin resistant PCOS (n = 24) and control (n = 24) women. Inflammatory proteins and matrix metalloproteinases were correlated to 25-hydroxy vitamin D₃ (25(OH)D₃), its epimer 25-hydroxy-3epi-vitamin D (3epi25(OH)D) and the active 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) as measured by gold standard isotope-dilution liquid chromatography tandem mass spectrometry. Results. PCOS women had both an elevated free androgen index and circulating anti-mullerian hormone, though insulin resistance was comparable to controls. C-reactive protein, as a standard circulatory marker of inflammation, was comparable between cohorts. Levels of circulating inflammatory proteins and matrix metalloproteinases were not different between the PCOS and control women, with no correlation of 25(OH)D_3, 1,25(OH)₂D₃ or 3epi25(OH)D with any of the inflammatory proteins. Conclusion. In a non-obese PCOS population matched for age and insulin resistance, circulating inflammatory proteins and matrix metalloproteinases were not elevated and did not correlate with 25(OH)D_3, its epimer 3epi25(OH)D or 1,25(OH)₂D₃ in either control or PCOS women, indicating that the inflammatory response is absent and the vitamin D-metabolite independent in non-obese women with PCOS.

Classical and alternate complement factor overexpression in non-obese weight matched women with polycystic ovary syndrome does not correlate with vitamin D

INTRODUCTION

Women with polycystic ovary syndrome (PCOS) exhibit complement factor expression changes that may be obesity-driven rather than an intrinsic facet of PCOS; furthermore, complement changes have been associated with vitamin D deficiency, a common feature of PCOS. Therefore, complement pathway proteins and vitamin D levels may be linked in PCOS.

METHODS

We measured plasma levels of complement pathway proteins by Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement for the classical (C4, C4a, and C4b) and alternative pathways (C3, C3b, iC3b, properdin, and factors B, D, and H) in weight and age-matched non-obese non-insulin resistant women with PCOS (n = 24) and control women (n = 24). Proteins that differed between groups were correlated with 25-hydroxyvitamin D₃ (25(OH)D₃) and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), measured by isotope-dilution liquid chromatography tandem mass spectrometry.

RESULTS

Women with PCOS had a higher free androgen index and anti-Mullerian hormone, though insulin resistance was comparable to controls; likewise, C-reactive protein, a marker of inflammation, was comparable between cohorts. In the alternative complement pathway, C3, iC3b, and properdin were increased in PCOS (p <0.05), while C4 in the classical pathway was increased (p <0.05). 25(OH)D₃ levels positively correlated with C3b only in control subjects, with no correlation of 1,25(OH)₂D₃ with any of the proteins.

CONCLUSION

In a non-obese PCOS population matched for age, insulin resistance and inflammation, initiating proteins of the classical and alternate complement cascades were increased. However, a positive correlation with 25(OH)D₃ was only seen for C3b in control subjects, with no correlation to 1,25(OH)₂D₃, suggesting that the increase in complement proteins in PCOS is vitamin D-independent.