Short-term therapy with combination dipeptidyl peptidase-4 inhibitor saxagliptin/metformin extended release (XR) is superior to saxagliptin or metformin XR monotherapy in prediabetic women with polycystic ovary syndrome: a single-blind, randomized, pilot study

Drug repurposing for cancer therapy

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.

Comparative Effectiveness of Antidiabetic Drugs as an Additional Therapy to Metformin in Women with Polycystic Ovary Syndrome: A Systematic Review of Metabolic Approaches

Background

Metformin is commonly prescribed to treat polycystic ovary syndrome (PCOS) patients, but in some cases, it may not be effective even at high doses or may cause intolerable side effects. Therefore, recent studies have examined the impact of combining metformin with other antidiabetic medications.

Methods

A systematic search was performed in Scopus, PubMed, Web of Science, and Embase up to 30 June 2023. All interventional studies that assessed the efficacy of different antidiabetic agents were included.

Results

Among the 3488 records found in the primary search, 16 papers were included. Our study showed that dipeptidyl peptidase-4 inhibitors (DPP4i) had the most significant impact on glycemic profile, while thiazolidinediones (TZDs) had the most influence on lipid levels. However, it was observed that patients taking only metformin experienced a greater increase in high-density lipoprotein cholesterol (HDL-C) levels. Glucagon-like peptide-1 receptor agonists (GLP1RAs) effectively modified various anthropometric measurements, such as weight, body mass index, waist circumference, and waist-to-hip ratio. The effects of different antidiabetic drugs on hormone levels were inconclusive, although testosterone levels were more affected by GLP1RA, sodium-glucose cotransporter-2 inhibitors (SGLT2i), and TZDs. None of the combined therapies showed a significant change in blood pressure.

Conclusion

Since PCOS is a metabolic disorder, choosing the best combination of antidiabetic drugs in the clinical course of PCOS patients will be very important. Today, it seems that we need a new metabolic approach for better treatment of the metabolic aspects of these patients.

Infertility Improvement after Medical Weight Loss in Women and Men: A Review of the Literature

Infertility is a modern health problem. Obesity is another expanding health issue associated with chronic diseases among which infertility is also included. This review will focus on the effects of weight loss by medical therapy on fertility regarding reproductive hormonal profile, ovulation rates, time to pregnancy, implantation rates, pregnancy rates, normal embryo development, and live birth rates. We comprised medicine already used for weight loss, such as orlistat and metformin, and emerging medical treatments, such as Glucagon-Like Peptide-1 receptor agonists (GLP-1 RA). Their use is not recommended during a planned pregnancy, and they should be discontinued in such cases. The main outcomes of this literature review are the following: modest weight loss after medication and the duration of the treatment are important factors for fertility improvement. The fecundity outcomes upon which medical-induced weight loss provides significant results are the female reproductive hormonal profile, menstrual cyclicity, ovulation and conception rates, and pregnancy rates. Regarding the male reproductive system, the fertility outcomes that feature significant alterations after medically induced weight loss are as follows: the male reproductive hormonal profile, sperm motility, movement and morphology, weight of reproductive organs, and sexual function. The newer promising GLP-1 RAs show expectations regarding fertility improvement, as they have evidenced encouraging effects on improving ovulation rates and regulating the menstrual cycle. However, more human studies are needed to confirm this. Future research should aim to provide answers about whether medical weight loss therapies affect fertility indirectly through weight loss or by a possible direct action on the reproductive system.

Polycystic ovary syndrome: Current scenario and future insights

Polycystic ovary syndrome (PCOS) prevails in approximately 33% of females of reproductive age globally. Although the root cause of the disease is unknown, attempts are made to clinically manage the disturbed hormone levels and symptoms arising due to hyperandrogenism, a hallmark of PCOS. This review presents detailed insights on the etiology, risk factors, current treatment strategies, and challenges therein. Medicinal agents currently in clinical trials and those in the development pipeline are emphasized. The significance of the inclusion of herbal supplements in PCOS and the benefits of improved lifestyle are also explained. Last, emerging therapeutic targets for treating PCOS are elaborated. The present review will assist the research fraternity working in the concerned domain to access significant knowledge associated with PCOS.

The Illustration of Altered Glucose Dependency in Drug-Resistant Cancer Cells

A chemotherapeutic approach is crucial in malignancy management, which is often challenging due to the development of chemoresistance. Over time, chemo-resistant cancer cells rapidly repopulate and metastasize, increasing the recurrence rate in cancer patients. Targeting these destined cancer cells is more troublesome for clinicians, as they share biology and molecular cross-talks with normal cells. However, the recent insights into the metabolic profiles of chemo-resistant cancer cells surprisingly illustrated the activation of distinct pathways compared with chemo-sensitive or primary cancer cells. These distinct metabolic dynamics are vital and contribute to the shift from chemo-sensitivity to chemo-resistance in cancer. This review will discuss the important metabolic alterations in cancer cells that lead to drug resistance.

Pharmacological Management of Obesity in Patients with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. A substantial proportion of patients with PCOS are either overweight or obese, and excess body weight aggravates the hormonal, reproductive and metabolic manifestations of PCOS. In recent years, several studies evaluated the role of various pharmacological agents in the management of obesity in this population. Most reports assessed glucagon-like peptide-1 receptor agonists and showed a substantial reduction in body weight. More limited data suggest that sodium-glucose cotransporter-2 inhibitors and phosphodiesterase-4 inhibitors might also be effective in the management of obesity in these patients. In the present review, we discuss the current evidence on the safety and efficacy of these agents in overweight and obese patients with PCOS.

Evidence for Involvement of GIP and GLP-1 Receptors and the Gut-Gonadal Axis in Regulating Female Reproductive Function in Mice

Substantial evidence suggests crosstalk between reproductive and gut-axis but mechanisms linking metabolism and reproduction are still unclear. The present study evaluated the possible role of glucose-dependent-insulinotropic-polypeptide (GIP) and glucagon-like-peptide-1 (GLP-1) in reproductive function by examining receptor distribution and the effects of global GIPR and GLP-1R deletion on estrous cycling and reproductive outcomes in mice. GIPR and GLP-1R gene expression were readily detected by PCR in female reproductive tissues including pituitary, ovaries and uterine horn. Protein expression was confirmed with histological visualisation of incretin receptors using GIPR-Cre and GLP1R-Cre mice in which the incretin receptor expressing cells were fluorescently tagged. Functional studies revealed that female GIPR-/- and GLP-1R-/- null mice exhibited significantly (p < 0.05 and p < 0.01) deranged estrous cycling compared to wild-type controls, indicative of reduced fertility. Furthermore, only 50% and 16% of female GIPR-/- and GLP-1R-/- mice, respectively produced litters with wild-type males across three breeding cycles. Consistent with a physiological role of incretin receptors in pregnancy outcome, litter size was significantly (p < 0.001-p < 0.05) decreased in GIPR-/- and GLP-1R-/- mice. Treatment with oral metformin (300 mg/kg body-weight), an agent used clinically for treatment of PCOS, for a further two breeding periods showed no amelioration of pregnancy outcome except that litter size in the GIPR-/- group was approximately 2 times greater in the second breeding cycle. These data highlight the significance of incretin receptors in modulation of female reproductive function which may provide future targets for pharmacological intervention in reproductive disorders.

Impact of pharmacological interventions on anthropometric indices in women with polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials

CONTEXT

Polycystic ovary syndrome (PCOS) is a heterogeneous condition affecting women of reproductive age and is associated with increased body weight.

OBJECTIVE

To review the literature on the effect of different pharmacological interventions on the anthropometric indices in women with PCOS.

DATA SOURCES

We searched PubMed, MEDLINE, Scopus, Embase, Cochrane library, and the Web of Science in April 2020 with an update in PubMed in March 2021.

STUDY SELECTION

The study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)2020.

DATA EXTRACTION

Reviewers extracted data and assessed the risk of bias using the Cochrane risk of bias tool.

RESULTS

80 RCTs were included in the meta-analysis. Metformin vs placebo showed significant reduction in the mean body weight (MD: -3.13 kg; 95% confidence interval [CI]: -5.33 to -0.93, I² = 5%) and the mean body mass index (BMI) (MD: -0.75 kg/m² ; 95% CI: -1.15 to -0.36, I² = 0%). There was a significant reduction in the mean BMI with orlistat versus placebo (MD: -1.33 kg/m²; 95% CI: -2.16 to -0.66, I² = 0.0%), acarbose versus metformin (MD: -1.26 kg/m²; 95% CI: -2.13 to -0.38, I² = 0%), and metformin versus pioglitazone (MD: -0.91 kg/m²; 95% CI: -1.62 to -0.19, I² = 0%). A significant increase in the mean BMI was also observed in pioglitazone versus placebo (MD: + 2.59 kg/m²; 95% CI: 1.78-3.38, I² = 0%) and in rosiglitazone versus metformin (MD: + 0.80 kg/m²; 95% CI: 0.32-1.27, I² = 3%). There was a significant reduction in the mean waist circumference (WC) with metformin versus placebo (MD: -1.21 cm; 95% CI: -3.71 to 1.29, I² = 0%) while a significant increase in the mean WC with pioglitazone versus placebo (MD: + 5.45 cm; 95% CI: 2.18-8.71, I² = 0%).

CONCLUSION

Pharmacological interventions including metformin, sitagliptin, pioglitazone, rosiglitazone orlistat, and acarbose have significant effects on the anthropometric indices in women with PCOS.

Impact of pharmacological interventions on biochemical hyperandrogenemia in women with polycystic ovary syndrome: a systematic review and meta-analysis of randomised controlled trials

CONTEXT

Polycystic ovary syndrome (PCOS) is a complex endocrine disease that affects women of reproductive age and is characterised by biochemical and clinical androgen excess.

AIM

To evaluate the efficacy of pharmacological interventions used to decrease androgen hormones in women with PCOS.

DATA SOURCE

We searched PubMed, MEDLINE, Scopus, Embase, Cochrane library and the Web of Science from inception up to March 2021.

DATA SYNTHESIS

Two reviewers selected eligible studies and extracted data, and the review is reported according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Of the 814 randomised clinical trials (RCTs) located in the search, 92 met the eligibility criteria. There were significant reductions in total testosterone level with metformin versus (vs) placebo (SMD: - 0.33; 95% CI  - 0.49 to  - 0.17, p < 0.0001, moderate grade evidence) and dexamethasone vs placebo (MD:-0.86 nmol/L; 95% CI  - 1.34 to  - 0.39, p = 0.0004, very low-grade evidence). Significant reductions in the free testosterone with sitagliptin vs placebo (SMD:  - 0.47; 95% CI  - 0.97 to 0.04, p = 0.07, very low-grade evidence), in dehydroepiandrosterone sulphate (DHEAS) with flutamide vs finasteride (MD:  - 0.37 µg/dL; 95% CI  - 0.05 to  - 0.58, p = 0.02, very low-grade evidence), a significant reduction in androstenedione (A4) with rosiglitazone vs placebo (SMD:  - 1.67; 95% CI  - 2.27 to  - 1.06; 59 participants, p < 0.00001, very low-grade evidence), and a significant increase in sex hormone-binding globulin (SHBG) with oral contraceptive pill (OCP) (35 µg Ethinyl Estradiol (EE)/2 mg cyproterone acetate (CPA)) vs placebo (MD: 103.30 nmol/L; 95% CI 55.54-151.05, p < 0.0001, very low-grade evidence) were observed.

CONCLUSION

Metformin, OCP, dexamethasone, flutamide, and rosiglitazone use were associated with a significant reduction in biochemical hyperandrogenemia in women with PCOS, though their individual use may be limited due to their side effects.

PROSPERO REGISTRATION NO

CRD42020178783.

Effect of pharmacological interventions on lipid profiles and C-reactive protein in polycystic ovary syndrome: A systematic review and meta-analysis

CONTEXT

Polycystic ovary syndrome (PCOS) is a heterogeneous condition affecting women of reproductive age. It is associated with dyslipidaemia and elevated plasma C-reactive protein (CRP), which increase the risks of cardiovascular disease (CVD).

OBJECTIVE

To review the existing evidence on the effects of different pharmacological interventions on lipid profiles and CRP of women with PCOS.

DATA SOURCES

We searched PubMed, MEDLINE, Scopus, Embase, Cochrane Library, and Web of Science in April 2020 and updated the results in March 2021.

STUDY SELECTION

The study included randomized controlled trials (RCTs) and follows the 2020 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA).

DATA EXTRACTION

Two independent researchers extracted data and assessed for risk of bias using the Cochrane risk of bias tool. Covidence systematic review software were used for blinded screening and study selection.

DATA SYNTHESIS

In 29 RCTs, there were significant reductions in triglycerides with atorvastatin versus placebo [mean difference (MD): -0.21 mmol/L; 95% confidence interval (CI): -0.39, -0.03, I²  = 0%, moderate grade evidence]. Significant reductions were seen for low-density lipoprotein cholesterol (LDL-C) with metformin versus placebo [standardized mean difference (SMD): -0.41; 95% CI: -0.85, 0.02, I²  = 59%, low grade evidence]. Significant reductions were also seen for total cholesterol with saxagliptin versus metformin (MD: -0.15 mmol/L; 95% CI: -0.23, -0.08, I²  = 0%, very low grade evidence). Significant reductions in C-reactive protein (CRP) were seen for atorvastatin versus placebo (MD: -1.51 mmol/L; 95% CI: -3.26 to 0.24, I²  = 75%, very low-grade evidence).

CONCLUSION

There were significant reductions in the lipid parameters when metformin, atorvastatin, saxagliptin, rosiglitazone and pioglitazone were compared with placebo or other agents. There was also a significant reduction of CRP with atorvastatin.

Impact of pharmacological interventions on insulin resistance in women with polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a complex endocrine condition affecting women of reproductive age. It is characterized by insulin resistance and is a major risk factor for type 2 diabetes mellitus (T2DM). The objective was to review the literature on the effect of different pharmacological interventions on insulin resistance in women with PCOS.

DESIGN

We searched PubMed, MEDLINE, Scopus, Embase, Cochrane library and the Web of Science in April 2020 and updated in March 2021. The study follows the 2020 Preferred Reporting Items for Systematic reviews and Meta-ana. Reviwers extracted data and assessed the risk of bias using the Cochrane risk of bias tool.

RESULTS

In 58 randomized controlled trials there were significant reductions in the fasting blood glucose (FBG) with metformin versus placebo (standardized mean difference [SMD]: -0.23; 95% confidence interval [CI]: -0.40, -0.06; I² = 0%, low-grade evidence), and acarbose versus metformin (mean difference [MD]: -10.50 mg/dl; 95% CI: -15.76, -5.24; I² = 0%, low-grade evidence). Significant reductions in fasting insulin (FI) with pioglitazone versus placebo (SMD: -0.55; 95% CI: -1.03, -0.07; I² = 37%; p = .02, very-low-grade evidence). A significant reduction in homoeostatic model assessment of insulin resistance (HOMA-IR) was seen with exenatide versus metformin (MD: -0.34; 95% CI: -0.65, -0.03; I² = 0%, low-grade evidence). No effect on homoeostatic model assessment of beta cells (HOMA-B) was observed.

CONCLUSIONS

Pharmacological interventions, including metformin, acarbose, pioglitazone and exenatide have significant effects on FBG, FI, HOMA-IR but not on HOMA-B.

Exploring the dual character of metformin in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, which results in dementia typically in the elderly. The disease is mainly characterized by the deposition of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain. However, only few drugs are available for AD because of its unknown pathological mechanism which limits the development of new drugs. Therefore, it is urgent to identify potential therapeutic strategies for AD. Moreover, research have showed that there is a significant association between Type 2 diabetes mellites (T2DM) and AD, suggesting that the two diseases may share common pathophysiological mechanisms. Such mechanisms include impaired insulin signaling, altered glucose metabolism, inflammation, oxidative stress, and premature aging, which strongly affect cognitive function and increased risk of dementia. Consequently, as a widely used drug for T2DM, metformin also has therapeutic potential for AD in vivo. It has been confirmed that metformin is beneficial on the brain of AD animal models. The mechanisms underlying the effects of metformin in Alzheimer's disease are complex and multifaceted. Metformin may work through mechanisms involving homeostasis of glucose metabolism, decrease of amyloid plaque deposition, normalization of tau protein phosphorylation and enhancement of autophagy. However, in clinical trials, metformin had little effects on patients with mild cognitive impairment or mild AD. Pathological effects and negative clinical results of metformin on AD make the current topic quite controversial. By reviewing the latest progress of related research, this paper summarizes the possible role of metformin in AD. The purpose of this study is not only to determine the potential treatment of AD, but also other related neurodegenerative diseases.

Exenatide, Metformin, or Both for Prediabetes in PCOS: A Randomized, Open-label, Parallel-group Controlled Study

CONTEXT

Up to 40% of patients with polycystic ovary syndrome (PCOS) have prediabetes; an optimal pharmacotherapy regimen for diabetes prevention in PCOS is yet to be established.

OBJECTIVE

To evaluate clinical efficacy of exenatide (EX), metformin (MET), or combination (COM) for prediabetes in PCOS.

DESIGN

Randomized, open-label, parallel-group controlled trial.

SETTING

Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.

PATIENTS

PCOS with prediabetes (fasting plasma glucose 5.6-6.9 mmol/L and/or 2 hour post glucose 7.8-11.0 mmol/L on oral glucose tolerance test [OGTT]). A total of 150 out of 183 eligible enrollees completed the study.

INTERVENTION

EX (10-20μg daily), MET (1500-2000 mg daily), or COM (EX plus MET) for 12 weeks.

MAIN OUTCOME MEASURES

Sustained remission rate of prediabetes (primary endpoint, a normal OGTT after 12 weeks of treatment followed by 12 weeks of washout on no drug treatment) along with anthropometric, hormonal, metabolic, and pancreatic β-cell function parameters (secondary endpoints) and potential mechanisms were assessed.

RESULTS

Impaired glucose tolerance was found the dominant prediabetes phenotype. Overall sustained prediabetes remission rate was 50.7%. Remission rate of COM group (64%, 32/50) or EX group (56%, 28/50) was significantly higher than that of the MET group (32%, 16/50) (P = .003 and .027, respectively). EX was associated with superior suppression of 2-hour glucose increment in OGTT. A 2-step hyperglycemic clamp study revealed that EX had led to higher postprandial insulin secretion than MET, potentially explaining the higher remission rate.

CONCLUSIONS

Compared with MET monotherapy, EX or COM achieved higher rate of remission of prediabetes among PCOS patients by improving postprandial insulin secretion.

The potential role of incretin-based therapies for polycystic ovary syndrome: a narrative review of the current evidence

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age. Metabolic consequences associated with PCOS include, but are not limited to, insulin resistance (IR), type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). This narrative review aims to provide a comprehensive overview of the potential therapeutic roles of the incretin-based therapies in the management of PCOS.

METHODS

We performed a systematic search of databases including PubMed, MEDLINE and EMBASE up to 1 October 2020. We developed a search string of medical subject headings (MeSH) including the terms PCOS, incretin mimetics, glucagon-like peptide-1 (GLP-1), glucagon-like peptide-1 receptor antagonists (GLP-1 RAs), liraglutide, exenatide, semaglutide, dipeptidyl peptidase-4 (DPP-4) inhibitors, combined with IR, testosterone and sex hormone-binding globulin (SHBG).

RESULTS

We identified 854 relevant articles and, after the initial screening, eight interventional animal studies, one observational animal study, 14 interventional human studies, two case-control studies and one systematic review were included. These studies showed the potential significant roles of GLP-1 RAs and DPP-4 inhibitors in the management of PCOS, with significant improvements in the metabolic parameters, including substantial weight reduction and improved insulin sensitivity. These agents also improved the hormonal parameters through decreased free androgen and increased SHBG. Moreover, they improved menstrual regularity, increased fertility with enhanced ovulation and pregnancy in obese women with PCOS.

CONCLUSION

GLP-1 RAs and DPP-4 inhibitors have a promising therapeutic role in PCOS; however, larger clinical trials are needed to establish the role of incretin-based therapies in the management of PCOS.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.

Effects of metformin on body weight in polycystic ovary syndrome patients: model-based meta-analysis

OBJECTIVES

The present study aimed to investigate the effects of metformin on body weight in polycystic ovary syndrome (PCOS) patients by model-based meta-analysis (MBMA).

METHODS

Randomized controlled trial (RCT) studies of metformin in treatment of PCOS patients were collected and efficacy indicators were the body mass index (BMI) change rates from baseline.

RESULTS

28 RCT studies, 1631 PCOS patients were included for analysis. Model of metformin monotherapy, and model of metformin combination therapy were established, respectively. After deducting control group effects, the E_max of metformin on BMI were -5.88% and -11.8% in metformin monotherapy and metformin combination therapy, respectively. In order to play better curative effects, for metformin monotherapy, 1000 mg/day metformin needs for at least 25.5 weeks; For metformin combination therapy, 1000 mg/day metformin needs for at least 58.6 weeks.

CONCLUSION

It was the first time to quantify the effects of metformin on body weight and recommend dose and duration for metformin monotherapy and metformin combination therapy in PCOS patients.

The role of glucagon-like peptide-1 in reproduction: from physiology to therapeutic perspective

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) have become firmly established in the treatment of type 2 diabetes and obesity, disorders frequently associated with diminished reproductive health. Understanding of the role of GLP-1 and GLP-1 RAs in reproduction is currently limited and largely unaddressed in clinical studies.

OBJECTIVE AND RATIONALE

The purpose of this narrative review is to provide a comprehensive overview of the role of GLP-1 in reproduction and to address a therapeutic perspective that can be derived from these findings.

SEARCH METHODS

We performed a series of PubMed database systemic searches, last updated on 1 February 2019, supplemented by the authors' knowledge and research experience in the field. A search algorithm was developed incorporating the terms glucagon-like peptide-1, GLP-1, glucagon-like peptide-1 receptor, GLP-1R, or incretins, and this was combined with terms related to reproductive health. The PICO (Population, Intervention, Comparison, Outcome) framework was used to identify interventional studies including GLP-1 RAs and dipeptidyl peptidase-4 (DPP-4) inhibitors, which prevent the degradation of endogenously released GLP-1. We identified 983 potentially relevant references. At the end of the screening process, we included 6 observational (3 preclinical and 3 human) studies, 24 interventional (9 preclinical and 15 human) studies, 4 case reports, and 1 systematic and 2 narrative reviews.

OUTCOMES

The anatomical distribution of GLP-1 receptor throughout the reproductive system and observed effects of GLP-1 in preclinical models and in a few clinical studies indicate that GLP-1 might be one of the important modulating signals connecting the reproductive and metabolic system. The outcomes show that there is mostly stimulating role of GLP-1 and its mimetics in mammalian reproduction that goes beyond mere weight reduction. In addition, GLP-1 seems to have anti-inflammatory and anti-fibrotic effects in the gonads and the endometrium affected by obesity, diabetes, and polycystic ovary syndrome (PCOS). It also seems that GLP-1 RAs and DPP-4 inhibitors can reverse polycystic ovary morphology in preclinical models and decrease serum concentrations of androgens and their bioavailability in women with PCOS. Preliminary data from interventional clinical studies suggest improved menstrual regularity as well as increased fertility rates in overweight and/or obese women with PCOS treated with GLP-1 RAs in the preconception period.

WIDER IMPLICATIONS

GLP-1 RAs and DPP-4 inhibitors show promise in the treatment of diabetes and obesity-related subfertility. Larger interventional studies are needed to establish the role of preconception intervention with GLP-1 based therapies, assessing fertility outcomes in obesity, PCOS, and diabetes-related fertility problems. The potential impact of the dose- and exposure time-response of different GLP-1 RAs need further exploration. Future research should also investigate sex-specific variability of GLP-1 on reproductive outcomes, in particular on the gonads where the observations in males are most conflicting.

What is new in the landscape of insulin-sensitizing agents for polycystic ovary syndrome treatment

Polycystic ovary syndrome, the most common gynecological endocrinopathy, is burdened with a state of hyperinsulinemia and insulin resistance in 50-80% of affected women. Wherever the origin of these metabolic abnormalities lies, their pathogenetic role in determining, perpetuating, and worsening the clinical traits of the syndrome is ascertained. Many studies have already highlighted possible mechanisms: hyperinsulinemia and insulin resistance may contribute to hyperandrogenemia, chronic anovulation, and other comorbidities of the syndrome by differentially affecting the endocrine glands (ovaries, adrenals, and pituitary) and peripheral tissues (fat mass and skeletal muscle). Based on these evidences, in the past years, thorough research has been focused on the possible role of insulin-sensitizing agents in the treatment of polycystic ovary syndrome. Many compounds were tested to verify their efficacy against polycystic ovary syndrome-related metabolic dysfunction, both relying on previous acquired experiences in the field of diabetes mellitus and experimenting new agents, in particular, those belonging to the class of nutraceuticals. We sought to summarize the most relevant aspects of insulin-sensitizing treatments in polycystic ovary syndrome, by reporting the relevant literature on this topic and by keeping an attentive eye on the newly published international guidelines on polycystic ovary syndrome 2018. This overview encompasses metformin, thiazolidinediones, inositols, alpha-lipoic acid, and GLP1-R analogues. Starting from the analysis of the mechanisms of action, we anchored to the state of the art of the use of these drugs in polycystic ovary syndrome, to the most recent evidences for clinical practice and to the remaining open questions around indications, dose, treatment schedules, and side effects.

Is Metformin the Answer for Distressed Females with Menstrual Irregularities?

This literature review is aimed to determine if metformin alone improves menstrual irregularities in females with the polycystic ovarian syndrome. The current literature review involves females with polycystic ovarian syndrome experiencing menstrual irregularity. The data was collected in PubMed and inclusion criteria included articles published in the past 10 years, articles involving only humans, articles written in the English language and considering women age 19 or more. The number of discovered articles was 1550 after the first search and only 25 articles that met the inclusion criteria were selected after quality assessment. The selected 25 articles that met the inclusion criteria after a review showed evidence for regulating menstrual cycles with metformin therapy alone among females with the polycystic ovarian syndrome. When metformin was used in addition to other pharmacologic agents, there was a more significant restoration of menstrual cycles. Monotherapy with metformin is found to be highly effective in treating menstrual irregularities experienced among patients with the polycystic ovarian syndrome. Greater improvement was noted with the addition of another agent to metformin. 

Emerging Topics in Cardiometabolic and Psychologic Sequelae, Pathogenesis, and Treatment of Polycystic Ovarian Syndrome: A Review

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder, affecting 6–10% of reproductive age women and influences the reproductive, metabolic, dermatologic, and psychiatric health of affected girls and women. Despite its prevalence, the pathogenesis of the disease is largely unknown, and treatment options are limited. Thus, PCOS has been a ripe area for research in recent years, and novel etiologic pathways, diagnostic parameters, and treatment options are being explored. This review focuses on recent data suggesting pathogenic and therapeutic considerations, as well as the psychiatric and metabolic sequelae of PCOS.

Comparison of glycemic control and β-cell function in new onset T2DM patients with PCOS of metformin and saxagliptin monotherapy or combination treatment

BACKGROUND

Impaired insulin activity in women with polycystic ovary syndrome might differ from that seen in type 2 diabetes mellitus without polycystic ovary syndrome. This study was designed to compare the effects of treatment with metformin, saxagliptin, and their combination in newly diagnosed women with type 2 diabetes mellitus and polycystic ovary syndrome in China.

METHODS

A total of 75 newly diagnosed patients from Shanghai, China with type 2 diabetes mellitus and polycystic ovary syndrome were included in this randomized, parallel, open-label study. All patients received treatment for 24 weeks with metformin, saxagliptin, or their combination. Patients were allocated to one of three treatment groups by a computer-generated code that facilitated equal patient distribution of 25 patients per group. The primary outcome was a change in glycemic control and β-cell function.

RESULTS

A total of 63 patients completed the study (n = 21, for each group). The reduction in hemoglobin A1c was significant in the combination group, compared to the monotherapy groups (saxagliptin vs. combination treatment vs. metformin: - 1.1 vs. -1.3 vs. -1.1%, P = 0.016), whereas it was comparable between the metformin and saxagliptin groups (P > 0.05). Saxagliptin, metformin, and the combination treatment significantly reduced the homeostasis model assessment- insulin resistance index and increased the deposition index (P < 0.01 for all). However, no significant change was observed in the homeostasis model assessment- β-cell function among the metformin and combination groups, and no significant changes were observed in the insulinogenic index among all three groups (P > 0.05 for all). In addition, saxagliptin and metformin treatments significantly reduced body mass index and high-sensitivity C-reactive protein levels (P < 0.01 for both).

CONCLUSIONS

Saxagliptin and metformin were comparably effective in regulating weight loss, glycemic control, and β-cell function, improving lipid profiles, and reducing inflammation in newly diagnosed type 2 diabetes mellitus patients with polycystic ovary syndrome.

TRIAL REGISTRATION

ChiCTR-IPR-17011120 (retrospectively registered on 2017-04-12).

A review of dipeptidyl peptidase-4 inhibitors. Hot topics from randomized controlled trials

The first clinical study to investigate effects of dipeptidyl peptidase-4 (DPP-4) inhibition was published in 2002, and since then, numerous randomized controlled trials (RCTs) have shown that DPP-4 inhibitors are efficacious, safe and well-tolerated. This review will focus upon RCTs which have investigated DPP-4 inhibitors in patient groups which are often under-represented or excluded from typical phase 3 clinical trials. Large cardiovascular (CV) safety outcome trials in patients with established CV disease have confirmed that DPP-4 inhibitors are not associated with any additional CV risk in these already-at-high-risk individuals, while raising awareness of any uncommon adverse events, such as heart failure hospitalization seen in one of the trials. Studies in patients with kidney disease have shown DPP-4 inhibitors to be efficacious without increasing the risk of hypoglycaemia, irrespective of the degree of renal impairment, while data from the large CV trials as well as smaller RCTs have even pointed towards potential renoprotective effects such individuals. The use of DPP-4 inhibitors with insulin when therapy requires intensification may be beneficial without affecting the incidence or severity of hypoglycaemia, with these effects also being replicated in patients with chronic kidney disease, for whom other agents may not be suitable. Attention is now turning towards exploring the potential utility of DPP-4 inhibitors in other circumstances, including for in-hospital management of hyperglycaemia and in other metabolic disorders. Together, these RCTs raise the possibility that in the future, DPP-4 inhibitors may have a broader use which may extend beyond glycaemic control in the typical type 2 diabetes mellitus (T2DM) patient seen in general practice and may encompass conditions other than T2DM.