Metformin therapy increases insulin-like growth factor binding protein-1 in hyperinsulinemic women with polycystic ovary syndrome

Metformin enhances epithelial cell growth inhibition via the protein kinase-insulin-like growth factor binding protein-1 pathway

BACKGROUND

Abnormal stromal-epithelial cell communication is a pathogenic mechanism in endometriosis, and metformin can modulate it. Insulin-like growth factor binding protein-1 (IGFBP1) plays a role in endometriosis, but the exact mechanism is unknown. IGFBP1 is reportedly a downstream target of metformin in some diseases. We aimed to investigate the role of IGFBP1 in endometriosis development, whether it is associated with abnormal communication, and whether metformin affects IGFBP1 expression.

METHODS

Patients who underwent surgical treatment for endometriosis or other diseases were enrolled. Ten patients with ovarian-type endometriosis and eight patients each who underwent surgical treatment for other lesions with or without endometriosis were selected, and their tissues taken for cell proliferation, western blotting, polymerase chain reaction, and knockdown experiments.

RESULTS

Ectopic and eutopic stromal cells (EcSCs and EuSCs) lost their ability to inhibit epithelial cell proliferation, and IGFBP1 expression was downregulated in both groups of stromal cells compared to that in normal stromal cells (NSCs; 1.09 vs. 0.25, p = .0002 1.09 vs. 0.57, p = .0029). In an EcSC IGFBP1 overexpression model, the ability of EcSCs to inhibit epithelial cell proliferation was enhanced (EdU positivity decreased from 38% to 25%, p = .0001). Furthermore, adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation was downregulated in EcSCs and EuSCs compared to that in NSCs (0.99 vs. 0.42, p = .0006/0.99 vs. 0.57, p = 0.0032). Treatment of EcSCs with metformin increased AMPK phosphorylation (0.47 vs. 1.04, p = .0107) while upregulating IGFBP1 expression (0.69 vs. 1.01, p = .0164), whereas pre-treatment with an AMPK phosphorylation inhibitor abrogated metformin-induced IGFBP1 upregulation.

CONCLUSIONS

IGFBP1 mediates aberrant stromal-epithelial communication in endometriosis. Metformin can upregulate IGFBP1 expression in EcSCs by activating AMPK, and upregulated IGFBP1 enhances the inhibition of epithelial cell proliferation. IGFBP1 is expected to be a therapeutic target for endometriosis.

Metformin: A Potential Treatment for Acne, Hidradenitis Suppurativa and Rosacea

Metformin is a widely used drug for treatment of diabetes mellitus, due to its safety and efficacy. In addition to its role as an antidiabetic drug, numerous beneficial effects of metformin have enabled its use in various diseases. Considering the anti-androgenic, anti-angiogenic, anti-fibrotic and antioxidant properties of metformin, it may have the potential to improve chronic inflammatory skin diseases. However, further evidence is needed to confirm the efficacy of metformin in dermatological conditions, This review focuses on exploring the therapeutic targets of metformin in acne vulgaris, hidradenitis suppurativa and rosacea, by studying their pathogeneses.

The relationship between polycystic ovary syndrome and insulin resistance from 1983 to 2022: A bibliometric analysis

Background

Polycystic ovary syndrome (PCOS) is a common clinical disease often associated with insulin resistance (IR). The interaction between PCOS and IR will promote the progress of PCOS and the risk of related complications, harm women's physical and mental health, and increase the social and economic burden.

Materials and Methods

PCOS IR-related works of literature were retrieved through the Web of Science Core Collection (WoSCC) Database and imported into VOSviewer and CiteSpace, respectively, in plain text format to conduct the literature visualization analysis of authors, countries, institutions, highly cited works of literature, and keywords, aiming to reveal the hot spots and trends of PCOS IR fields.

Results

A total of 7,244 articles were retrieved from 1900 to 2022. Among them, the United States has made the largest contribution. Diamanti-Kandarakis E was the author with the most publications, and the University of Athens was the institution with most publications. Keyword analysis showed that PCOS interacts with IR mainly through sex-hormone binding globulin, luteinizing hormone, insulin-like growth factor, oxidative stress, and other mechanisms. In addition, the complications of PCOS complicated with IR are also the focus of researchers' attention.

Conclusions

Through bibliometric analysis, this paper obtains the research hotspot and trend of PCOS IR fields, which can provide a reference for subsequent research.

Insulin-like growth factor role in determining the anti-cancer effect of metformin: RCT in prostate cancer patients

OBJECTIVE

Androgen deprivation therapy (ADT), a principal therapy in patients with prostate cancer, is associated with the development of obesity, insulin resistance, and hyperinsulinemia. Recent evidence indicates that metformin may slow cancer progression and improves survival in prostate cancer patients, but the mechanism is not well understood. Circulating insulin-like growth factors (IGFs) are bound to high-affinity binding proteins, which not only modulate the bioavailability and signalling of IGFs but also have independent actions on cell growth and survival. The aim of this study was to investigate whether metformin modulates IGFs, IGF-binding proteins (IGFBPs), and the pregnancy-associated plasma protein A (PAPP-A) - stanniocalcin 2 (STC2) axis.

DESIGN AND METHODS

In a blinded, randomised, cross-over design, 15 patients with prostate cancer on stable ADT received metformin and placebo treatment for 6 weeks each. Glucose metabolism along with circulating IGFs and IGFBPs was assessed.

RESULTS

Metformin significantly reduced the homeostasis model assessment as an index of insulin resistance (HOMA IR) and hepatic insulin resistance. Metformin also reduced circulating IGF-2 (P < 0.05) and IGFBP-3 (P < 0.01) but increased IGF bioactivity (P < 0.05). At baseline, IGF-2 correlated significantly with the hepatic insulin resistance (r2= 0.28, P < 0.05). PAPP-A remained unchanged but STC2 declined significantly (P < 0.05) following metformin administration. During metformin treatment, change in HOMA IR correlated with the change in STC2 (r2= 0.35, P < 0.05).

CONCLUSION

Metformin administration alters many components of the circulating IGF system, either directly or indirectly via improved insulin sensitivity. Reduction in IGF-2 and STC2 may provide a novel mechanism for a potential metformin-induced antineoplastic effect.

Perspectives of metformin use in endometrial cancer and other gynaecological malignancies

Insulin resistance and hyperinsulinemia play a key role in type 1 endometrial cancer pathogenesis. Most of these cancers develop on a background of overweight or type 2 diabetes mellitus (T2DM). One of the medications widely used in the treatment of T2DM is biguanide derivative, metformin, which exerts promising anticancer properties principally through activation of adenosine monophosphate kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) pathways. Many epidemiological studies on diabetic patients show potential preventative role of metformin in endometrial cancer patients, but data regarding its therapeutic role is still limited. So far, most of attention has been paid to the concept of metformin use in fertility sparing treatment of early-stage cancer. Another investigated alternative is its application in patients with primary advanced or recurrent disease. In this review we present the latest data on clinical use of metformin in endometrial cancer patients and potential underlying mechanisms of its activity. Finally, we present some most important clinical information regarding metformin efficacy in other gynaecological malignancies, mainly breast and ovarian cancer.

Metformin and insulin treatment of gestational diabetes: effects on inflammatory markers and IGF-binding protein-1 - secondary analysis of a randomized controlled trial

Background

Gestational diabetes mellitus (GDM) is characterized by disturbed glucose metabolism and activation of low-grade inflammation. We studied whether metformin treatment has favorable or unfavorable effects on inflammatory markers and insulin-like growth factor-binding protein 1 (IGFBP-1) in GDM patients compared with insulin, and whether these markers associate with major maternal or fetal clinical outcomes.

Methods

This is a secondary analysis of a previous randomized controlled trial comparing metformin (n = 110) and insulin (n = 107) treatment of GDM. Fasting serum samples were collected at the time of diagnosis (baseline, mean 30 gestational weeks [gw]) and at 36 gw. Inflammatory markers serum high-sensitivity CRP (hsCRP), interleukin-6 (IL-6), matrix metalloproteinase-8 (MMP-8) and glycoprotein acetylation (GlycA) as well as three IGFBP-1 phosphoisoform concentrations were determined.

Results

In the metformin and insulin groups combined, hsCRP decreased (p = 0.01), whereas IL-6 (p = 0.002), GlycA (p < 0.0001) and all IGFBP-1 phosphoisoforms (p < 0.0001) increased from baseline to 36 gw. GlycA (p = 0.02) and non-phosphorylated IGFBP-1 (p = 0.008) increased more in patients treated with metformin than those treated with insulin. Inflammatory markers did not clearly associate with pregnancy outcomes but non-phosphorylated IGFBP-1 was inversely associated with gestational weight gain.

Conclusions

Metformin had beneficial effects on maternal serum IGFBP-1 concentrations compared to insulin, as increased IGFBP-1 related to lower total and late pregnancy maternal weight gain. GlycA increased more during metformin treatment compared to insulin. The significance of this observation needs to be more profoundly examined in further studies. There were no evident clinically relevant relations between inflammatory markers and pregnancy outcome measures.

Trial registration

The trial comparing metformin and insulin treatment was registered in ClinicalTrials.gov (NCT01240785) November 3, 2010. Retrospectively registered.

Metformin therapy and the risk of colorectal adenoma in patients with type 2 diabetes: A meta-analysis

BACKGROUND

Existing data evaluating the impact of metformin on the colorectal adenoma (CRA) risk in patients suffering from type 2 diabetes (T2D) are limited and controversial. We therefore summarized the studies currently available and assessed the relationship between metformin treatment and risk of CRA in T2D patients.

METHODS

We systematically searched databases for eligible studies that explored the impact of metformin treatment on the occurrence of CRA in T2D patients from inception to June 2016. The summary odds ratio (OR) estimates with their 95% confidence interval (CI) were derived using random-effect, generic inverse variance methods. Sensitivity analysis and subgroup analysis were performed.

RESULTS

Seven studies involving 7178 participants met the inclusion criteria. The pooling showed that metformin therapy has a 27% decrease in the CRA risk (OR, 0.73; 95% CI, 0.58 - 0.90). In subgroup analysis, we detected that metformin exhibits significant chemoprevention effects in Asia region (OR, 0.68; 95% CI, 0.48 - 0.96). Similar results were identified in both studies with adjusted ORs and high-quality studies (OR, 0.66; 95% CI, 0.50 - 0.86 and OR, 0.70; 95% CI, 0.58 - 0.84, respectively). Of note, an inverse relationship was noted that metformin therapy may result in a significant decrease in the advanced adenoma risk (OR, 0.52; 95% CI, 0.38 - 0.72). Low heterogeneity was observed, however, the results remained robust in multiple sensitivity analyses.

CONCLUSIONS

This meta-analysis indicates that metformin therapy is correlated with a significant decrease in the risk of CRA and advanced adenoma in T2D patients. Further confirmatory studies are warranted.

Phase II study of metformin for reduction of obesity-associated breast cancer risk: a randomized controlled trial protocol

Background

Two-thirds of U.S. adult women are overweight or obese. High body mass index (BMI) and adult weight gain are risk factors for a number of chronic diseases, including postmenopausal breast cancer. The higher postmenopausal breast cancer risk in women with elevated BMI is likely to be attributable to related metabolic disturbances including altered circulating sex steroid hormones and adipokines, elevated pro-inflammatory cytokines, and insulin resistance. Metformin is a widely used antidiabetic drug that has demonstrated favorable effects on metabolic disturbances and as such may lead to lower breast cancer risk in obese women. Further, the anti-proliferative effects of metformin suggest it may decrease breast density, an accepted biomarker of breast cancer risk.

Methods/design

This is a Phase II randomized, double-blind, placebo-controlled trial of metformin in overweight/obese premenopausal women who have elements of metabolic syndrome. Eligible participants will be randomized to receive metformin 850 mg BID (n = 75) or placebo (n = 75) for 12 months. The primary endpoint is change in breast density, based on magnetic resonance imaging (MRI) acquired fat-water features. Secondary outcomes include changes in serum insulin levels, serum insulin-like growth factor (IGF)-1 to insulin-like growth factor binding protein (IGFBP)-3 ratio, serum IGF-2 levels, serum testosterone levels, serum leptin to adiponectin ratio, body weight, and waist circumference. Exploratory outcomes include changes in metabolomic profiles in plasma and nipple aspirate fluid. Changes in tissue architecture as well as cellular and molecular targets in breast tissue collected in a subgroup of participants will also be explored.

Discussion

The study will evaluate whether metformin can result in favorable changes in breast density, select proteins and hormones, products of body metabolism, and body weight and composition. The study should help determine the potential breast cancer preventive activity of metformin in a growing population at risk for multiple diseases.

Trial registration

ClinicalTrials.gov Identifier: NCT02028221. Registered on January 2, 2014. Grant #: 1R01CA172444-01A1 awarded on Sept 11, 2013.

Metformin may protect nondiabetic breast cancer women from metastasis

Metformin, a widely prescribed oral hypoglycemic agent, has recently received a big interest because of its potential antitumorigenic effects in different cancer types. The present study investigated the impact of adding metformin to breast cancer adjuvant therapy in nondiabetic women on, insulin like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), insulin, fasting blood glucose (FBG), the molar ratio of IGF-1 to IGFBP-3, homeostatic model assessment of insulin resistance (HOMA-IR) and metastasis. 102 women with newly diagnosed breast cancer were divided into 2 main groups, a control group and a metformin group. All women were treated with adjuvant therapy, according to the protocols of Ministry of Health and Population and National Cancer Institute, Egypt. Moreover, the women in the metformin group received 850 mg of metformin twice daily. Blood samples were collected at baseline, after chemotherapy (CT), after 6 months of hormonal therapy (6-HT) and 12 months of hormonal therapy (12-HT) for analysis of serum IGF-1, IGFBP-3, insulin, FBG and cancer antigen 15-3 (CA15-3). Metformin resulted in a significant reduction of IGF-1, IGF-1: IGFBP-3 molar ratio, insulin, FBG and HOMA-IR. On the other hand, metformin caused a significant increase of IGFBP-3. Moreover, metformin significantly decreased the numbers of metastatic cases after 6-HT. Metformin may have potential antitumor and antimetastatic effects that need further clinical investigations. This may be attributed to either the significant increase of the apoptotic inducer IGFBP-3 or/and the significant reduction of mitogenic insulin, IGF-1, free bioactive IGF-1, FBG and HOMA-IR.

Metformin inhibits hepatocellular glucose, lipid and cholesterol biosynthetic pathways by transcriptionally suppressing steroid receptor coactivator 2 (SRC-2)

The ability of the anti-diabetic drug metformin to inhibit anabolic processes including gluconeogenesis and lipogenesis is partly attributable to activation of the AMP-activated protein kinase (AMPK) pathway. The p160 steroid receptor coactivator 2 (SRC-2) is a key regulator of cellular metabolism and drives expression of the gluconeogenic enzyme glucose-6-phosphatase (G6Pc). Here, we uncovered a role for SRC-2 in the metabolic reprogramming imposed by metformin. In FaO cells, metformin dose-dependently reduced mRNA expression of SRC-2. Microarray analysis of metformin-treated cells revealed an overrepresentation of downregulated genes involved in biosynthesis of lipids and cholesterol. Several metformin-regulated genes including fatty acid synthase (FASN) were validated as transcriptional targets of SRC-2 with promoters characterized by sterol regulatory element (SRE) binding protein (SREBP) recognition sequences. Transactivation assays of the FASN promoter confirmed that SRC-2 is a coactivator of SREBP-1. By suppressing SRC-2 at the transcriptional level, metformin impeded recruitment of SRC-2 and RNA polymerase II to the G6Pc promoter and to SREs of mutual SRC-2/SREBP-1 target gene promoters. Hepatocellular fat accretion was reduced by metformin or knock-down of both SRC-2 and SREBP-1. Accordingly we propose that metformin inhibits glucose and lipid biosynthesis partly by downregulating SRC-2 gene expression.

Is it time to test biguanide metformin in the treatment of melanoma?

Metformin is the most widely used antidiabetic drug that belongs to the biguanide class. It is very well tolerated and has the major clinical advantage of not inducing hypoglycemia. Metformin decreases hepatic glucose production via a mechanism requiring liver kinase B1, which controls the metabolic checkpoint, AMP-activated protein kinase-mammalian target of rapamycin and neoglucogenic genes. The effects of metformin on this pathway results in reduced protein synthesis and cell proliferation. These observations have given the impetus for many investigations on the role of metformin in the regulation of tumor cell proliferation, cell-cycle regulation, apoptosis, and autophagy. Encouraging results from these studies have shown that metformin could potentially be used as an efficient anticancer drug in various neoplasms such as prostate, breast, lung, pancreas cancers, and melanoma. These findings are strengthened by retrospective epidemiological studies that have found a decrease in cancer risk in diabetic patients treated with metformin. In this review, we have focused our discussion on recent molecular mechanisms of metformin that have been described in various solid tumors in general and in melanoma in particular.

Metformin: On Ongoing Journey across Diabetes, Cancer Therapy and Prevention

Cancer metabolism is the focus of intense research, which witnesses its key role in human tumors. Diabetic patients treated with metformin exhibit a reduced incidence of cancer and cancer-related mortality. This highlights the possibility that the tackling of metabolic alterations might also hold promising value for treating cancer patients. Here, we review the emerging role of metformin as a paradigmatic example of an old drug used worldwide to treat patients with type II diabetes which to date is gaining strong in vitro and in vivo anticancer activities to be included in clinical trials. Metformin is also becoming the focus of intense basic and clinical research on chemoprevention, thus suggesting that metabolic alteration is an early lesion along cancer transformation. Metabolic reprogramming might be a very efficient prevention strategy with a profound impact on public health worldwide.

Metformin and neoplasia: implications and indications

Metformin has been shown to exert anti-neoplastic and chemopreventive activities in epidemiological and animal studies. This review article discusses the epidemiological studies and examines the possible mechanisms by which metformin exerts its anti-carcinogenic activities in breast, colon, ovarian, lung, and prostate cancers. We performed a systematic review of the clinical studies examining the anti-neoplastic activities of metformin and the potential mechanisms associated with these activities. Several observational and biological studies revealed a significant association between metformin and reduction in cancer incidence. The mechanisms by which metformin exerts these effects are unknown. This action may be mediated through activation of AMP-activated protein kinase (AMPK), inhibition of the mammalian target of rapamycin (mTOR) pathway, and inhibition of insulin like growth factors (IGFs), and many others. Further laboratory investigation and large, prospective population clinical trials are required to elucidate metformin anti-neoplastic and chemo-preventive actions.

Metformin as a geroprotector

Abstract Geroprotectors are drugs that decrease the rate of aging and therefore extend life span. Metformin has been described as a geroprotector, and several studies have shown that metformin can slow down the rate of aging. The mechanisms behind the geroprotective effect of metformin are less established. The goal of this review is to investigate the evidence for the geroprotective effect of metformin and to describe the possible mechanisms behind it.

Effects of metformin treatment in women with polycystic ovary syndrome depends on insulin resistance

Polycystic ovary syndrome (PCOS) affects 5-10% of women at reproductive age, and is the most common reason for hyperandrogenism and chronic anovulation. Some patients with PCOS are insulin-resistant. Also, lowered sex hormone-binding globulin (SHBG) concentration is usually observed. As a consequence, the amount of free and biologically active androgens increases. This implies that, by improving insulin and carbohydrate metabolism, metformin administration in PCOS patients could indirectly contribute to increase SHBG concentration. The aim of the present study was to assess the effects of metformin treatment in PCOS patients both with and without insulin resistance. Thirty-six patients completed treatment. Body mass index (BMI) was considerably reduced after therapy. Statistically significant decreases were noted in luteinizing hormone (LH) and fasting insulin concentrations and the free androgen index (FAI), and significant increases in follicle-stimulating hormone (FSH)/LH ratio and SHBG concentration. In the insulin-resistant group, BMI and fasting insulin concentrations were reduced considerably after treatment, and SHBG increased slightly. In the group of patients without insulin resistance, BMI, LH and FAI showed significant reductions, and FSH/LH and SHBG considerable increases. Considering the favorable effects of metformin treatment in PCOS patients both with insulin resistance and without it, it is purposeful to use this drug in both groups of women.

Growth factors and folliculogenesis in polycystic ovary patients

Ovarian folliculogenesis is regulated by a fine balance between endocrine and intraovarian factors. In this review, we focus on the role of growth factors in physiological folliculogenesis and in polycystic ovaries. Recent evidence shows that the main systems implicated in polycystic ovary folliculogenesis are the growth hormone and insulin-like growth factor system, vascular endothelial growth factor, and the transforming growth factor-β family. Growth hormone and the insulin-like growth factor system could affect follicular development and oocyte maturation if their balance was altered, while vascular endothelial growth factor is implied in follicular dominance by providing an increasing vascular supply. The transforming growth factor-β family is composed of various molecules, which have different roles in cellular proliferation. Finally, a series of different factors seem to be involved in altered polycystic ovary follicular growth.

Serum sex hormone-binding globulin levels show too much variability to be used effectively as a screening marker for insulin resistance in women with polycystic ovary syndrome

OBJECTIVE

To evaluate the relationship between serum sex hormone-binding globulin (SHBG) and parameters of insulin sensitivity in women with polycystic ovary syndrome (PCOS) and controls, and determine the feasibility of using SHBG levels to predict insulin resistance.

DESIGN

Evaluation of a prospectively collected database.

SETTING

University reproductive center.

PATIENT(S)

A total of 21 women with PCOS and 17 controls.

INTERVENTION(S)

Oral glucose tolerance test.

MAIN OUTCOME MEASURE(S)

Correlations of serum SHBG and parameters of insulin sensitivity.

RESULT(S)

[1] Among all participants, SHBG levels indicated a correlation between the fasting glucose-to-insulin (GI) ratio and the quantitative insulin sensitivity check index (QUICKI). Participants with PCOS demonstrated significant correlations of SHBG and fasting GI ratio, 1-hour postglucola insulin levels, and random 17-hydroxyprogesterone (17ohP4) levels. Among controls, SHBG and fasting serum glucose and 2-hour postglucola serum glucose levels were associated. [2] Participants with PCOS and lean controls exhibited different glucose and insulin responses to 75 g of glucose at 1 and 2 hours postchallenge, resulting in paradoxically similar GI ratios.

CONCLUSION(S)

[1] Although certain parameters of insulin status and serum SHBG demonstrated statistically significant correlation coefficients, these relationships are weak and SHBG cannot be used as a predictor of insulin resistance. [2] The post-glucose load GI ratio cannot be used to determine the magnitude of insulin resistance.

Use of metformin for prevention of ovarian hyperstimulation syndrome: a novel approach

In the present study, which includes 287 participants, metformin has been used by women undergoing IVF/intracytoplasmic sperm injection for more than 5 weeks before and during treatment and during luteal phase. There was no significant difference in number of gonadotrophins used, days of stimulation, number of oocytes retrieved, and number of embryos replaced. There was no significant difference in clinical pregnancy rate between both groups but there was significant reduction in the incidence of ovarian hyperstimulation syndrome (OHSS) in the group taking metformin. Metformin is a safe, cheap drug that can help in prevention of OHSS.

A randomized controlled trial evaluating metformin pre-treatment and co-administration in non-obese insulin-resistant women with polycystic ovary syndrome treated with controlled ovarian stimulation plus timed intercourse or intrauterine insemination

BACKGROUND

There are few data in the literature regarding the utility of metfomin before and during gonadotrophin administration in women with polycystic ovary syndrome (PCOS). The aim of the present study was to assess the effect of the pre-treatment and co-administration of metformin in infertile PCOS women treated with controlled ovarian stimulation (COS) followed by timed intercourse (TI) or intrauterine insemination (IUI).

METHODS

Seventy insulin-resistant primary infertile women with PCOS were randomized to receive metformin cloridrate (850 mg twice daily; group A) or placebo tablets (two tablets daily; group B) for 3 months. Three trials of COS using highly purified urinary FSH (hpFSH) plus TI/IUI were performed. Number of ampoules of gonadotrophin used, duration of the ovarian stimulation, cycle cancellation, ovulation, pregnancy, abortion, live birth, mono-ovulatory cycles, multiple pregnancies and ovarian hyperstimulation syndrome (OHSS) rates were assessed.

RESULTS

No difference between groups was detected in ovulation, cycle cancellation, pregnancy, abortion, live birth, multiple pregnancies and OHSS rates. The mono-ovulatory cycle rates were significantly (P = 0.002) more frequent in group A than in group B, whereas the days of stimulation for non-cancelled cycles and the number of vials of gonadotrophins used were significantly (P < 0.001) higher in group A than in group B.

CONCLUSION

In insulin-resistant women with PCOS, metformin pre-treatment and co-administration with hpFSH increases the mono-ovulatory cycles.

Metformin in polycystic ovary syndrome

PURPOSE OF REVIEW

Metformin has become an established treatment for women with polycystic ovary syndrome, although controversy remains as to how effective it is and in which populations it should be used. This review examines the recent literature in order to ascertain the evidence for the benefits and disadvantages of using metformin in women with polycystic ovary syndrome.

RECENT FINDINGS

A Cochrane systematic review and metaanalysis examined the evidence for metformin in treating polycystic ovary syndrome. Since this was published there have been a number of new trials, some of which have been reasonably large involving participants from many different countries.

SUMMARY

Evidence shows that metformin is effective in inducing ovulation, has some marginal benefit in improving aspects of the metabolic syndrome, improves objective measures of hirsutism, and seems to be effective in both obese and lean individuals. However, it has significant side effects, and the high levels of effectiveness that were reported by some early trials have not been replicated. Metformin should always be used as an adjuvant to general lifestyle improvements, and not as a replacement for increased exercise and improved diet.