Proteomic biomarkers for the diagnosis and risk stratification of polycystic ovary syndrome: a systematic review

Serum kisspeptin as a promising biomarker for PCOS: a mini review of current evidence and future prospects

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age, characterised by its multifactorial nature and intricate interplay of genetic, hormonal, and environmental factors. As the search for reliable biomarkers intensifies, serum kisspeptin emerges as a promising candidate due to its central role in regulating the hypothalamic-pituitary-gonadal (HPG) axis. This review aims to consolidate the evolving understanding of kisspeptin as a potential PCOS biomarker, comprehensively exploring its physiological basis, diagnostic challenges in PCOS, and clinical implications. Diagnostic challenges in PCOS are addressed, underscoring the limitations of current criteria and the need for objective and standardised biomarkers. Kisspeptin's introduction as a potential biomarker brings forth both promises and challenges in terms of its diagnostic utility. The review recognises the importance of standardisation in research methodologies and emphasises the exploration of genetic polymorphisms to enhance kisspeptin's robustness as a diagnostic tool.

Trends in metabolic dysfunction in polycystic ovary syndrome: a bibliometric analysis

Polycystic ovary syndrome (PCOS) is a very common chronic disease and causes reproductive disorders in women of childbearing age worldwide. The cause of metabolic dysfunction in PCOS is unknown, and there is a lack of systematic bibliometric analysis for this disease. This study included 3,972 articles on metabolic dysfunction in PCOS published from 2012 to 2021. We applied the VOSviewer and the CiteSpace scientometric analysis software to analyze the data regarding the publication of the articles, countries, authors, institutions, scientific categories, cited journals, and keywords. Through this analysis, we determined the research efforts and their developing trends and anticipated the progress in understanding PCOS-related metabolic dysfunction.

Risk of endometrial cancer in patients with polycystic ovarian syndrome: A meta‑analysis

While existing literature suggests an association between polycystic ovarian syndrome (PCOS) and endometrial cancer, the sparsity and inconsistency of current evidence indicates a lack of clarity regarding the exact strength of this association. It also remains uncertain whether the degree of risk of disease is affected by confounding factors, such as age and body mass index (BMI). The present meta-analysis is aimed to quantify the risk of endometrial cancer in female subjects with PCOS compared to those without PCOS. PubMed, MEDLINE, EMBASE, Scopus and Cochrane were searched from inception to October 31, 2022, to identify peer-reviewed case-control, cohort and cross-sectional studies that assessed the association between endometrial cancer and PCOS and contained original data. Two researchers independently extracted data and performed quality assessment using the Newcastle-Ottawa criteria. Pooled odds ratios (ORs) were calculated using the random-effect model and inverse variance. The degree of heterogeneity was assessed using I² statistics. A total of 10 relevant studies were identified and included in the meta-analysis (comprising 12,248 female patients with PCOS and 54,120 controls). Females with PCOS had a significantly increased odds of developing endometrial cancer as compared to those without PCOS [OR, 4.07; 95% confidence interval (CI), 2.13-7.78; P<0.0001]. When postmenopausal subjects (age, >54 years) were excluded from the meta-analysis, the odds increased further (OR, 5.14; 95% CI, 3.22-8.21; P<0.00001). Patients with PCOS are up to 5 times more likely to develop endometrial cancer compared to those without PCOS. Larger, prospective studies that are well-controlled for confounding factors, such as BMI, are required.

Follicular Fluid: A Powerful Tool for the Understanding and Diagnosis of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) represents one of the leading causes of anovulatory infertility and affects 5% to 20% of women worldwide. Until today, both the subsequent etiology and pathophysiology of PCOS remain unclear, and patients with PCOS that undergo assisted reproductive techniques (ART) might present a poor to exaggerated response, low oocyte quality, ovarian hyperstimulation syndrome, as well as changes in the follicular fluid metabolites pattern. These abnormalities originate a decrease of Metaphase II (MII) oocytes and decreased rates for fertilization, cleavage, implantation, blastocyst conversion, poor egg to follicle ratio, and increased miscarriages. Focus on obtaining high-quality embryos has been taken into more consideration over the years. Nowadays, the use of metabolomic analysis in the quantification of proteins and peptides in biological matrices might predict, with more accuracy, the success in assisted reproductive technology. In this article, we review the use of human follicular fluid as the matrix in metabolomic analysis for diagnostic and ART predictor of success for PCOS patients.

Raman Spectrum of Follicular Fluid: A Potential Biomarker for Oocyte Developmental Competence in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive women where abnormal folliculogenesis is considered as a common characteristic. Our aim is to evaluate the potential of follicular fluid (FF) Raman spectra to predict embryo development and pregnancy outcome, so as to prioritize the best promising embryo for implantation, reducing both physiological and economical burdens of PCOS patients. In addition, the altered metabolic profiles will be identified to explore the aetiology and pathobiology of PCOS. In this study, follicular fluid samples obtained from 150 PCOS and 150 non-PCOS women were measured with Raman spectroscopy. Individual Raman spectrum was analyzed to find biologic components contributing to the occurrence of PCOS. More importantly, the Raman spectra of follicular fluid from the 150 PCOS patients were analyzed via machine-learning algorithms to evaluate their predictive value for oocyte development potential and clinical pregnancy. Mean-centered Raman spectra and principal component analysis (PCA) showed global differences in the footprints of follicular fluid between PCOS and non-PCOS women. Two Raman zones (993-1,165 cm^-1 and 1,439-1,678 cm^-1) were identified for describing the largest variances between the two groups, with the former higher and the latter lower in PCOS FF. The tentative assignments of corresponding Raman bands included phenylalanine and β -carotene. Moreover, it was found that FF, in which oocytes would develop into high-quality blastocysts and obtain high clinical pregnancy rate, were detected with lower quantification of the integration at 993-1,165 cm^-1 and higher quantification of the integration at 1,439-1,678 cm^-1 in PCOS. In addition, based on Raman spectra of PCOS FF, the machine-learning algorithms via the fully connected artificial neural network (ANN) achieved the overall accuracies of 90 and 74% in correctly assigning oocyte developmental potential and clinical pregnancy, respectively. The study suggests that the PCOS displays unique metabolic profiles in follicular fluid which could be detected by Raman spectroscopy. Specific bands in Raman spectra have the biomarker potential to predict the embryo development and pregnancy outcome for PCOS patients. Importantly, these data may provide some valuable biochemical information and metabolic signatures that will help us to understand the abnormal follicular development in PCOS.

An increase of phosphatidylcholines in follicular fluid implies attenuation of embryo quality on day 3 post-fertilization

Background

Although oocyte quality is the dominant factor determining embryo quality, few studies have been conducted to evaluate embryo quality based on the metabolites related to the oocyte. With quantification of the follicular fluid (FF) metabolites, in assisted reproductive technology (ART), this study sought to evaluate the embryo or oocyte quality through an informative approach.

Results

An evaluation model consisting of 17 features was generated to distinguish the embryo quality on day 3 post-fertilization, and phosphatidylcholines (PCs) were the key contributors to the evaluation. The model was extended to the patients under different ages and hyperstimulations, and the features were further enriched to facilitate the evaluation of the embryo quality. The metabolites were clustered through pathway analysis, leading to a hypothesis that accumulation of arachidonic acid induced by PCs might weaken embryo quality on day 3 post-fertilization.

Conclusions

A discriminating model with metabolic features elicited from follicular fluid was established, which enabled the evaluation of the embryo or oocyte quality even under certain clinical conditions, and the increase of PCs in follicular fluid implies the attenuation of embryo quality on day 3 post-fertilization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-021-01118-w.

Metabolomic Insight into Polycystic Ovary Syndrome-An Overview

Searching for the mechanisms of the polycystic ovary syndrome (PCOS) pathophysiology has become a crucial aspect of research performed in the last decades. However, the pathogenesis of this complex and heterogeneous endocrinopathy remains unknown. Thus, there is a need to investigate the metabolic pathways, which could be involved in the pathophysiology of PCOS and to find the metabolic markers of this disorder. The application of metabolomics gives a promising insight into the research on PCOS. It is a valuable and rapidly expanding tool, enabling the discovery of novel metabolites, which may be the potential biomarkers of several metabolic and endocrine disorders. The utilization of this approach could also improve the process of diagnosis and therefore, make treatment more effective. This review article aims to summarize actual and meaningful metabolomic studies in PCOS and point to the potential biomarkers detected in serum, urine, and follicular fluid of the affected women.

Clinical, hormonal and metabolic parameters in women with PCOS with different combined oral contraceptives (containing chlormadinone acetate versus drospirenone)

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting 5-10% of women of reproductive age. It is characterized by chronic anovulation leading to menstrual disorders, and increased infertility. The syndrome can also manifest as hirsutism and acne.

AIM OF THE STUDY

The aim of the study was to compare, over a duration of 6 months, the effects of drospirenone (DRSP) versus chlormadinone acetate (CMA) containing oral contraceptives (OCs) on clinical, hormonal, and metabolic parameters in 120 PCOS women.

MATERIALS AND METHODS

120 women with the diagnosis of PCOS according to the Rotterdam 2003 criteria were recruited to the study. All patients were divided to two treatment groups of OCs, containing: 3 mg DRSP/30 mcg EE (ethinylestradiol) (60 patients) and 2 mg CMA/30 mcg EE (60 patients). Clinical parameters such as hirsutismus and acne were evaluated. Metabolic parameters such as serum insulin, glucose concentration, homeostatic model assessment of insulin resistance, body mass index, systolic and diastolic blood pressures were also measured. Among hormonal parameters, serum estradiol, luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, dehydroepiandrosterone sulfate, thyroid-stimulating hormone, and free thyroxine were measured.

RESULTS

The use of both DRSP- or CMA-containing OCs provided similar positive therapeutic effects with regard to clinical, metabolic, and hormonal parameters. Among clinical parameters, like hirsutismus, after 6 months of continuous OC treatment, a statistically significant improvement was observed in both groups: DRSP (p <  0.0001) and CMA OC treatment (p < 0.0001). In addition, significant improvement was showed according to acne lesions both after DRSP (p < 0.0001) and CMA treatments (p < 0.0001). Among glucose, insulin levels and HOMA-IR, there were statistically significant higher levels in both groups after DRSP (p < 0.0001, p < 0.0001, p < 0.05) and CMA OC treatment (p < 0.02, p < 0.0001, p < 0.0001). Hormonal parameters such as LH, FSH, prolactin, testosterone and DHEA-S were statistically significant lower in both groups after DRSP (p < 0.0001, p < 0.0001, p < 0.01, p < 0,002, and p < 0.0001) and CMA OC treatment (p < 0.0001, p < 0.0001, p < 0.04, p < 0.002, and p < 0.0001).

CONCLUSIONS

Further research, however, is needed not only to define optimal duration, and to clarify the effects of treatment on long-term metabolic outcomes, but also to explore different treatment options and possible combined therapies.

Serum ferritin as a candidate diagnostic biomarker of polycystic ovarian syndrome: a meta-analysis

Objective: In this study, we investigated about the potential of serum ferritin as a complementary diagnostic biomarker of polycystic ovarian syndrome (PCOS) by performing a meta-analysis of existing literature. Materials and methods: Eleven studies written in English were retrieved up to 30 June 2018. Data were extracted from the selected studies by two of the authors and was subjected to statistical analysis. Levels of serum ferritin were compared between women with PCOS and controls using the standardized mean difference (SMD) and 95% confidence interval (CI). Subgroup analysis was also performed and stratified by ethnicity (Asians versus Caucasians). Results: Overall post-outlier outcomes indicated that elevated serum ferritin is strongly associated with PCOS (SMD: 0.52; 95% CI: 0.40-0.64; P^A = 10^-5). Subgroup analysis by ethnicity showed no significant difference between Asian and Caucasian population. Post-outlier receiving operations characteristics curve were plotted and showed that values for serum ferritin showed good potential in discriminating patients with and without PCOS (AUC = 0.827, p = 0.006). Conclusion: Our findings suggest that high serum ferritin level is significantly associated with PCOS and its potential as a biomarker is evident in its high diagnostic accuracy. However, additional studies are needed to confirm our claims.

Proteomics of reproduction: Prospects and perspectives

In recent years, proteomics has been used widely in reproductive research in order to understand the molecular mechanisms related to gametes at the cellular level and the role of proteins involved in fertilization. Network and pathway analysis using bioinformatic tools have paved way to obtain a wider picture on the possible pathways associated with the key differentially expressed proteins (DEPs) and its implication in various infertility scenarios. A brief overview of advanced techniques and bioinformatic tools used for reproductive proteomics is presented. Key findings of proteomic-based studies on male and female reproduction are also presented. Furthermore, the chapter sheds light on the cellular pathways and potential biomarkers associated with male and female infertility. Proteomics coupled with bioinformatic analysis provides an ideal platform for non-invasive management of infertility in couples.

N-glycoproteomic analysis of human follicular fluid during natural and stimulated cycles in patients undergoing in vitro fertilization

OBJECTIVE

Hyperstimulation methods are broadly used for in vitro fertilization (IVF) in patients with infertility; however, the side effects associated with these therapies, such as ovarian hyperstimulation syndrome (OHSS), have not been well studied. N-glycoproteomes are subproteomes used for the remote sensing of ovarian stimulation in follicular growth. Glycoproteomic variation in human follicular fluid (hFF) has not been evaluated. In this study, we aimed to identify and quantify the glycoproteomes and N-glycoproteins (N-GPs) in natural and stimulated hFF using label-free nano-liquid chromatography/electrospray ionization-quad time-of-flight mass spectrometry.

METHODS

For profiling of the total proteome and glycoproteome, pooled protein samples from natural and stimulated hFF samples were selectively isolated using hydrazide chemistry to obtain the total proteomes and glycoproteomes. N-GPs were validated by the consensus sequence N-X-S/T (92.2% specificity for the N-glycomotif at p<0.05). All data were compared between natural versus hyperstimulated hFF samples.

RESULTS

We detected 41 and 44 N-GPs in the natural and stimulated hFF samples, respectively. Importantly, we identified 11 N-GPs with greater than two-fold upregulation in stimulated hFF samples compared to natural hFF samples. We also validated the novel N-GPs thyroxine-binding globulin, vitamin D-binding protein, and complement proteins C3 and C9.

CONCLUSION

We identified and classified N-GPs in hFF to improve our understanding of follicular physiology in patients requiring assisted reproduction. Our results provided important insights into the prevention of hyperstimulation side effects, such as OHSS.

Biomarker Profiles in Women with PCOS and PCOS Offspring; A Pilot Study

Objective

To study metabolic/inflammatory biomarker risk profiles in women with PCOS and PCOS offspring.

Design

Cross-sectional comparison of serum biomarkers.

Setting

University Medical Center Utrecht.

Patients

Hyperandrogenic PCOS women (HA-PCOS, n = 34), normoandrogenic PCOS women (NA-PCOS, n = 34), non-PCOS reference population (n = 32), PCOS offspring (n = 14, age 6–8 years), and a paedriatic reference population (n = 30).

Main Outcome Measure(s)

Clustering profile of adipocytokines (IL-1b, IL-6, IL-13, IL-17, IL-18, TNF-α, adiponectin, adipsin, leptin, chemerin, resistin, RBP4, DPP-IV/sCD26, CCL2/MCP-1), growth factors (PIGF, VEGF, sVEGF-R1), soluble cell adhesion molecules (sICAM-1/sCD54, sVCAM-1/sCD106), and other inflammatory related proteases (MMP-9, S100A8, Cathepsin S). Differences in median biomarker concentrations between groups, and associations with the free androgen index (FAI; Testosterone/SHBG x100).

Results

The cluster analysis identified leptin, RBP-4, DPP-IV and adiponectin as potential discriminative markers for HA-PCOS with a specifically strong correlation in cases with increased BMI. Leptin (R² = 0.219) and adiponectin (R² = 0.182) showed the strongest correlation with the FAI. When comparing median protein concentrations adult PCOS women with or without hyperandrogenemia, the most profound differences were observed for leptin (P < 0.001), DPP-IV (P = 0.005), and adiponectin (P < 0.001). Adjusting for age, BMI and multiple testing attenuated all differences. In PCOS offspring, MMP-9 (P = 0.001) and S100A8 (P < 0.001) concentrations were significantly higher compared to a healthy matched reference population, even after correcting for age and BMI and adjustment for multiple testing.

Conclusion

In this preliminary investigation we observed significant differences in adipocytokines between women with or without hyperandrogenic PCOS and non-PCOS controls, mostly influenced by BMI. Leptin and adiponectin showed the strongest correlation with the FAI in adult women with PCOS. In PCOS offspring other inflammatory biomarkers (MMP-9, S100A8) were increased, suggesting that these children may exhibit increased chronic low-grade inflammation. Additional research is required to confirm results of the current exploratory investigation.

Lipidomic analysis of plasma samples from women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common disorder affecting between 5 and 18 % of females of reproductive age and can be diagnosed based on a combination of clinical, ultrasound and biochemical features, none of which on its own is diagnostic. A lipidomic approach using liquid chromatography coupled with accurate mass high-resolution mass-spectrometry (LC-HRMS) was used to investigate if there were any differences in plasma lipidomic profiles in women with PCOS compared with control women at different stages of menstrual cycle. Plasma samples from 40 women with PCOS and 40 controls aged between 18 and 40 years were analysed in combination with multivariate statistical analyses. Multivariate data analysis (LASSO regression and OPLS-DA) of the sample lipidomics datasets showed a weak prediction model for PCOS versus control samples from the follicular and mid-cycle phases of the menstrual cycle, but a stronger model (specificity 85 % and sensitivity 95 %) for PCOS versus the luteal phase menstrual cycle controls. The PCOS vs luteal phase model showed increased levels of plasma triglycerides and sphingomyelins and decreased levels of lysophosphatidylcholines and phosphatidylethanolamines in PCOS women compared with controls. Lipid biomarkers of PCOS were tentatively identified which may be useful in distinguishing PCOS from controls especially when performed during the menstrual cycle luteal phase.

Systemic sclerosis biomarkers discovered using mass-spectrometry-based proteomics: a systematic review

CONTEXT

Systemic sclerosis (SSc) is an autoimmune disease with incompletely known physiopathology. There is a great challenge to predict its course and therapeutic response using biomarkers.

OBJECTIVE

To critically review proteomic biomarkers discovered from biological specimens from systemic sclerosis patients using mass spectrometry technologies.

METHODS

Medline and Embase databases were searched in February 2014.

RESULTS

Out of the 199 records retrieved, a total of 20 records were included, identifying 116 candidate proteomic biomarkers.

CONCLUSION

Research in SSc proteomic biomarkers should focus on biomarker validation, as there are valuable mass-spectrometry proteomics studies in the literature.

Validation of proteomic biomarkers previously found to be differentially expressed in women with polycystic ovary syndrome: a cross-sectional study

OBJECTIVES

The aim of this study was to independently validate proteomic biomarkers previously reported to be differentially expressed in women with Polycystic Ovary Syndrome (PCOS) compared with controls. This study focused on plasma proteomic biomarkers.

METHODS

This was a cross-sectional study at the University of Nottingham, in which samples from 30 PCOS and 30 control women were analysed by Western blotting.

RESULTS

Mean abundance ratios from Western blots of plasma total haptoglobin and haptoglobin beta proteins were 1.25 (CI 1.11-1.4) and 1.24 (CI 1.04-1.44). The mean abundance ratio from the blots of alpha-2 macroglobulin was however 1.05 (CI, 1-1.1). The mean PCOS/control BMI ratio was 1.18 (CI 1.17-1.20). There was no correlation between PCOS/control BMI ratio and alpha-2 macroglobulin, total haptoglobin and haptoglobin beta abundance ratios. There was also no correlation between PCOS/control insulin ratio and alpha-2 macroglobulin, total haptoglobin and haptoglobin beta abundance ratios.

CONCLUSIONS

Total haptoglobin and haptoglobin beta chain protein abundance was found to be elevated in women with PCOS compared with controls. We were unable to confirm decreased alpha-2 macroglobulin levels as reported in a previous study. Independent validation studies are required to validate early promising proteomic biomarkers in PCOS.

A proteomic analysis of human follicular fluid: comparison between fertilized oocytes and non-fertilized oocytes in the same patient

PURPOSE

Human follicular fluid constitutes the microenvironment of follicles and includes various biological active proteins that can affect follicle growth and oocyte fertilization. Conducting proteomic evaluations of human follicular fluid may be helpful for identifying potential biomarkers possibly possessing a predictive value for oocyte quality and the success of in vitro fertilization.

METHOD

We performed proteomic profiling of human follicular fluids containing oocytes that were fertilized and resulted in pregnancy and follicular fluids containing oocytes that were not fertilized in the same patients undergoing intracytoplasmic sperm injection using the LTQ Orbitrap coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) analyses.

RESULTS

We identified a total of 503 proteins in human follicular fluids containing fertilized and non-fertilized oocytes obtained from 12 patients. We also found that 53 proteins exhibited significantly different spectral counts between the two groups, including heparan sulfate proteoglycan perlecan, which showed significant upregulation in the follicular fluids containing fertilized oocytes in comparison with that observed in the follicular fluids containing non-fertilized oocytes.

CONCLUSION

Our results suggest a possibility that proteins identified by LC/MS/MS in follicular fluid might not only be involved in folliculogenesis, but also function as biomarkers possessing predictive potential for oocyte maturation and the success of IVF when their expression levels are significantly different between fertilized and non-fertilized oocytes, although no distinctive biomarkers were identified in the current study.

Proteomic biomarkers of endometrial cancer risk in women with polycystic ovary syndrome: a systematic review and biomarker database integration

There is a need for research studies into the molecular mechanisms underpinning the link between polycystic ovary syndrome (PCOS) and endometrial cancer (EC) to facilitate screening and to encourage the development of novel strategies to prevent disease progression. The objective of this review was to identify proteomic biomarkers of EC risk in women with PCOS. All eligible published studies on proteomic biomarkers for EC identified through the literature were evaluated. Proteomic biomarkers for EC were then integrated with an updated previously published database of all proteomic biomarkers identified so far in PCOS women. Nine protein biomarkers were similarly either under or over expressed in women with EC and PCOS in various tissues. These include transgelin, pyruvate kinase M1/M2, gelsolin-like capping protein (macrophage capping protein), glutathione S-transferase P, leucine aminopeptidase (cytosol aminopeptidase), peptidyl-prolyl cis-transisomerase, cyclophilin A, complement component C4A and manganese-superoxide dismutase. If validated, these biomarkers may provide a useful framework on which the knowledge base in this area could be developed and will facilitate future mathematical modelling to enhance screening and prevention of EC in women with PCOS who have been shown to be at increased risk.

Proteomic biomarkers of type 2 diabetes mellitus risk in women with polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) are at increased risk of developing insulin resistance and type 2 diabetes mellitus (T2DM). In this study, we attempted to list the proteomic biomarkers of PCOS and T2DM that have been published in the literature so far. We identified eight common biomarkers that were differentially expressed in both women with PCOS and T2DM when compared with healthy controls. These include pyruvate kinase M1/M2, apolipoprotein A-I, albumin, peroxiredoxin 2, annexin A2, α-1-B-glycoprotein, flotillin-1 and haptoglobin. These biomarkers could help improve our understanding of the links between PCOS and T2DM and could be potentially used to identify subgroups of women with PCOS at increased risk of T2DM. More studies are required to further evaluate the role these biomarkers play in women with PCOS and T2DM.

Proteomic biomarkers of preterm birth risk in women with polycystic ovary syndrome (PCOS): a systematic review and biomarker database integration

Background

Preterm Birth (PTB) is a major cause of neonatal mortality and morbidity. Women with Polycystic Ovary Syndrome (PCOS) are at high risk of PTB. There is a need for research studies to investigate the mechanisms linking PCOS and PTB, to facilitate screening, and develop novel preventative strategies.

Objective

To list all the proteomic biomarkers of PTB and integrate this list with the PCOS biomarker database to identify commonly expressed biomarkers of the two conditions.

Search Strategy

A systematic review of PTB biomarkers and update of PCOS biomarker database. All eligible published studies on proteomic biomarkers for PTB and PCOS identified through various databases were evaluated.

Selection Criteria

For the identification of the relevant studies, the following search terms were used: “proteomics”, “proteomic”, “preterm birth”, “preterm labour”, “proteomic biomarker” and “polycystic ovary syndrome”. This search was restricted to humans only

Data Collection and Analysis

A database on proteomic biomarkers for PTB was created while an already existing PCOS biomarker database was updated. The two databases were integrated and biomarkers that were co-expressed in both women with PCOS and PTB were identified and investigated.

Results

A panel of six proteomic biomarkers was similarly differentially expressed in women with PTB and women with PCOS compared to their respective controls (normal age-matched women in the case of PCOS studies and women with term pregnancy in the case of PTB studies). These biomarkers include Pyruvate kinase M1/M2, Vimentin, Fructose bisphosphonate aldolase A, Heat shock protein beta-1, Peroxiredoxin-1 and Transferrin.

Conclusions

These proteomic biomarkers (Pyruvate kinase M1/M2, Vimentin, Fructose bisphosphonate aldolase A, Heat shock protein beta-1, Peroxiredoxin-1 and Transferrin) can be potentially used to better understand the pathophysiological mechanisms linking PCOS and PTB. This would help to identify subgroups of women with PCOS at risk of PTB and hence the potential of developing preventative strategies.

Apolipoprotein A-IV as a novel gene associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder, affecting 6-10% of women of reproductive age. The etiology remains poorly understood. To investigate the differentially expressed proteins from PCOS patients versus healthy women, the protein expression in follicular fluid was analyzed using two-dimensional electrophoresis (2-DE). Since follicular fluid contains a number of secretory proteins required for oocyte fertilization and follicle maturation, it is possible that follicular fluid can be used as a provisional source for identifying pivotal proteins associated with PCOS. In this study, six overexpressed proteins [kininogen 1, cytokeratin 9, antithrombin, fibrinogen γ-chain, apolipoprotein A-IV (apoA-IV) precursor and α-1-B-glycoprotein (A1BG)] in follicular fluids from PCOS patients were identified with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) and nano LC-MS/MS. Western blot analysis confirmed that the protein expression levels of apoA-IV precursor and A1BG were increased in follicular fluid from PCOS patients compared with those from normal controls. The analysis of protein expression for other proteins revealed individual variation. These results facilitate the understanding of the molecular mechanisms of PCOS and provide candidate biomarkers for the development of diagnostic and therapeutic tools.

Metabonomics reveals plasma metabolic changes and inflammatory marker in polycystic ovary syndrome patients

Polycystic ovary syndrome (PCOS) is a common, clinically heterogeneous endocrine disorder affecting women of reproductive age, associated with endocrinopathy and metabolic abnormalities. Although some metabolic parameters have been investigated, very little information has been reported on the changes of small metabolites in biofluids. The aim of this study was to establish the metabolic profile of PCOS and compare it with that of controls. In this cross-sectional study of 34 women with PCOS and 36 controls, contents of small metabolites and lipids in plasma samples were measured using nuclear magnetic resonance (NMR)-based techniques and analyzed using multivariate statistical methods. Significant decrease (P < 0.05) in the levels of amino acids (leucine, isoleucine, methionine, glutamine, and arginine), citrate, choline, and glycerophosphocholine/phosphocholine (GPC/PC), and increase (P < 0.05) in the levels of lactate, dimethylamine (DMA), creatine, and N-acetyl glycoproteins were observed in PCOS patients compared with the controls. Subgroups of patients with obesity, metabolic syndrome, or hyperandrogenism exhibited greater metabolic deviations than their corresponding subgroups without these factors. PCOS patients have perturbations in amino acid metabolism, the tricarboxylic acid (TCA) cycle, and gut microflora, as well as mild disturbances in glucose and lipid metabolism. The elevated level of N-acetyl glycoproteins demonstrates the existence of low-grade chronic inflammation in PCOS patients.

Evaluating the association between endometrial cancer and polycystic ovary syndrome

BACKGROUND

Given the current lack of clarity in the published literature, we performed a systematic review of the literature to determine the exact strength of the association between polycystic ovary syndrome (PCOS) and endometrial cancer (EC).

METHODS

All published studies on the association between PCOS and EC identified through MEDLINE (1966-April 2011), EMBASE (1980-April 2011) and Cochrane (1998-April 2011). Original data were abstracted where available and summarized on a separate Microsoft Excel (2007) database for analysis. A total of 14 studies comparative and non-comparative were identified and included.

RESULTS

The non-comparative and comparative data suggested that women with PCOS were more likely to develop EC. A meta-analyses of five comparative studies showed an increased risk of EC in women with an odds ratio of 2.89 with a 95% confidence interval of 1.52-5.48.

CONCLUSIONS

Women with PCOS are about three times more likely to develop EC compared with women without it. This translates into a 9% lifetime risk of EC in Caucasian women with PCOS compared with 3% in women without it. Although most women (91%) with PCOS will not develop endometrial cancer, our study has shown that they are more likely at increased risk. More studies are required to clarify the exact molecular mechanisms, determine the best way of screening and preventing disease progression.

Defining salivary biomarkers using mass spectrometry-based proteomics: a systematic review

Recent advancements in mass spectrometric proteomics provide a promising result in utilizing saliva to explore biomarkers for diagnostic purposes. However, the issues of specificity or redundancy of disease-associated salivary biomarkers have not been described. This systematic review was therefore aimed to define and summarize disease-related salivary biomarkers identified by mass spectrometry proteomics. Peer-reviewed articles published through July 2009 within three databases were reviewed. Out of 243 articles, 21 studies were selected in this systematic review with conditions including Sjögren's syndrome, squamous cell carcinoma, dental caries, diabetes, breast cancer, periodontitis, gastric cancer, systemic sclerosis, oral lichen planus, bleeding oral cavity, and graft-versus-host disease. The sample size ranged from 3-41 in both diseased and control subjects, with no consensus on sample collection protocol. One hundred eighty biomarkers were identified in total; 87 upregulated, 63 downregulated, and 30 varying based on disease. Except for Sjögren's syndrome, the majority of studies with the same disease produce inconsistent biomarkers. Larger sample size and standardization of sample collection/treatment protocol may improve future studies.

Proteomic analysis of plasma in the polycystic ovary syndrome identifies novel markers involved in iron metabolism, acute-phase response, and inflammation

CONTEXT

Hypothesis-free approaches such as proteomic analysis may identify novel biomarkers for disease.

OBJECTIVE

The objective of the study was to compare the plasma proteome of patients presenting with the polycystic ovary syndrome (PCOS) with that of women without hyperandrogenism.

DESIGN

This was a case-control study.

SETTINGS

The study was conducted at an academic hospital.

PATIENTS

Patients included 12 PCOS patients and 12 women without hyperandrogenism.

INTERVENTIONS

Interventions included basal blood sampling.

MAIN OUTCOME MEASURES

Two-dimensional difference in-gel electrophoresis, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, Western blot, and ELISA analyses were measured.

RESULTS

Two-dimensional difference in-gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analyses identified haptoglobin beta-chain and alpha2-macroglobulin as proteins underexpressed in PCOS samples, whereas transferrin and kappa-free light chain were overexpressed. We were able to confirm only the underexpression of haptoglobin beta-chain in subsequent Western blot and ELISA analyses.

CONCLUSIONS

Proteomic analysis of plasma from PCOS patients revealed changes in protein expression in several acute-phase response proteins including isoforms of plasma haptoglobin, alpha2-macroglobulin, and transferrin and in kappa-free light chain. In addition to their role as inflammatory markers, some of these molecules play major roles in iron metabolism, further suggesting that iron metabolism and low-grade chronic inflammation may be involved in the pathogenesis of insulin-resistant disorders such as PCOS.

Framework for a systems approach to proteomic biomarker profiling in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in females of reproductive age, and its prevalence ranges between 6 and 8%. Associated problems include infertility, menstrual disorders, hirsutism and obesity. In addition, individuals with PCOS may be at increased risk of diabetes, endometrial cancer and, possibly, cardiovascular disease and breast cancer in later life. Biomarkers identified from proteomic analyses may help to improve the clinical management of PCOS, provided that new proteomic data can be integrated with existing knowledge and/or pathways implicated in disease etiology. In this study, a database of identity, descriptions and functions/pathways has been developed from 148 published proteomic biomarkers in PCOS. From analysis of the database, a variety of pathways possibly implicated in PCOS were determined, including those related to fibrinolysis, thrombosis, the antioxidant pathway and the immune system. This database, if developed further, will provide a framework for a systems approach to profiling biomarkers in the future.