Effects of down-regulated carbonic anhydrase 8 on cell survival and glucose metabolism in human colorectal cancer cell lines.

Carbonic anhydrase 8 (CA8) is a member of the α-carbonic anhydrase family but does not catalyze the reversible hydration of carbon dioxide. In the present study, we examined the effects of CA8 on two human colon cancer cell lines, SW480 and SW620, by suppressing CA8 expression through shRNA knockdown. Our results showed that knockdown of CA8 decreased cell growth and cell mobility in SW620 cells, but not in SW480 cells. In addition, downregulated CA8 resulted in a significant decrease of glucose uptake in both SW480 and SW620 cells. Interestingly, stable downregulation of CA8 decreased phosphofructokinase-1 expression but increased glucose transporter 3 (GLUT3) levels in SW620 cells. However, transient downregulation of CA8 fails to up-regulate GLUT3 expression, indicating that the increased GLUT3 observed in SW620-shCA8 cells is a compensatory effect. In addition, the interaction between CA8 and GLUT3 was evidenced by pull-down and IP assays. On the other hand, we showed that metformin, a first-line drug for type II diabetes patients, significantly inhibited cell migration of SW620 cells, depending on the expressions of CA8 and focal adhesion kinase. Taken together, our data demonstrate that when compared to primary colon cancer SW480 cells, metastatic colon cancer SW620 cells respond differently to downregulated CA8, indicating that CA8 in more aggressive cancer cells may play a more important role in controlling cell survival and metformin response. CA8 may affect glucose metabolism- and cell invasion-related molecules in colon cancer, suggesting that CA8 may be a potential target in future cancer therapy.

Safety vs price in the generic drug market: metformin.

OBJECTIVES: Generic medications represent 90% of prescriptions in the US market and provide a tremendous financial benefit for patients. Recently, multiple generic drugs have been recalled due to the presence of carcinogens, predominantly N-nitrosodimethylamine (NDMA), including an extensive recall of extended-release (ER) metformin products in 2020. STUDY DESIGN: Primary pharmaceutical quality testing and database analysis. METHODS: We tested marketed metformin immediate-release (IR) and ER tablets from a wide sample of generic manufacturers for the presence of carcinogenic impurities NDMA and N,N-dimethylformamide (DMF). We examined the association of level of impurity with drug price and the impact of the 2020 FDA recalls on unit price and prescription fill rate. RESULTS: Postrecall NDMA levels were significantly lower in metformin ER samples (standardized mean difference = -2.0; P = .01); however, we found continued presence of carcinogens above the FDA threshold in 2 of 30 IR samples (6.67%). Overall, the presence of contaminant levels was not significantly associated with price for either IR (NDMA: R2 = 0.142; P = .981; DMF: R2 = 0.382; P = .436) or ER (NDMA: R2 = 0.124; P = .142; DMF: R2 = 0.199; P = .073) samples. Despite recalls, metformin ER prescription fills increased by 8.9% while unit price decreased by 19.61% (P < .05). CONCLUSIONS: Recalls of metformin ER medications were effective in lowering NDMA levels below the FDA threshold; however, some samples of generic metformin still contained carcinogens even after FDA-announced recalls. The absence of any correlation with price indicates that potentially safer products are available on the market for the same price as poorer-quality products.

Metformin ameliorates endometrial thickness in a rat model of thin endometrium.

Metformin, a well-established anti-diabetic drug, is also used in managing various other metabolic disorders including polycystic ovarian syndrome (PCOS). There are evidences to show that metformin improves endometrial functions in PCOS women. However, fewer studies have explored the direct effects of metformin on endometrium. Previous in vitro studies have shown that therapeutic serum concentrations of metformin enhance endometrial epithelial cell proliferation. The present study was undertaken to investigate in vivo effects of metformin on endometrial proliferation in a rat model of thin endometrium. Toward this, a rat model of thin endometrium was developed. Metformin (0.1% or 1% w/v) was administrated orally for 15 days in rats with thin endometrium. Oral metformin administration for three consecutive estrous cycles (15 days) in the thin endometrium rat model led to an increase in endometrial thickness compared to sham endometrium. Histological analysis showed a significant increase in the number of endometrial glands (P < 0.05), stromal cells (P < 0.01) and blood vessels (P < 0.01) in metformin-treated (n = 10 in each group) uterine horns compared to sham (saline-treated) uterine horns in rats. The expression of proliferating cell nuclear antigen and vascular epithelial growth factor was found to be upregulated on treatment with 1% metformin-treated group (n = 7). However, pregnancy outcomes in the rats treated with metformin remained unaltered despite the restoration of endometrial thickness. In conclusion, the study demonstrated that metformin ameliorates endometrial thickness in a rat model of thin endometrium by increasing endometrial proliferation and angiogenesis, without restoration of embryo implantation.

Metformin Inhibits Zika Virus Infection in Trophoblast Cell Line.

Zika virus (ZIKV) infections have been associated with severe clinical outcomes, which may include neurological manifestations, especially in newborns with intrauterine infection. However, licensed vaccines and specific antiviral agents are not yet available. Therefore, a safe and low-cost therapy is required, especially for pregnant women. In this regard, metformin, an FDA-approved drug used to treat gestational diabetes, has previously exhibited an anti-ZIKA effect in vitro in HUVEC cells by activating AMPK. In this study, we evaluated metformin treatment during ZIKV infection in vitro in a JEG3-permissive trophoblast cell line. Our results demonstrate that metformin affects viral replication and protein synthesis and reverses cytoskeletal changes promoted by ZIKV infection. In addition, it reduces lipid droplet formation, which is associated with lipogenic activation of infection. Taken together, our results indicate that metformin has potential as an antiviral agent against ZIKV infection in vitro in trophoblast cells.

A practical evidence-based approach to management of type 2 diabetes in children and young people (CYP): UK consensus.

BACKGROUND: Type 2 diabetes in young people is an aggressive disease with a greater risk of complications leading to increased morbidity and mortality during the most productive years of life. Prevalence in the UK and globally is rising yet experience in managing this condition is limited. There are no consensus guidelines in the UK for the assessment and management of paediatric type 2 diabetes. METHODS: Multidisciplinary professionals from The Association of Children's Diabetes Clinicians (ACDC) and the National Type 2 Diabetes Working Group reviewed the evidence base and made recommendations using the Grading Of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. RESULTS AND DISCUSSION: Young people with type 2 diabetes should be managed within a paediatric diabetes team with close working with adult diabetes specialists, primary care and other paediatric specialties. Diagnosis of diabetes type can be challenging with many overlapping features. Diabetes antibodies may be needed to aid diagnosis. Co-morbidities and complications are frequently present at diagnosis and should be managed holistically. Lifestyle change and metformin are the mainstay of early treatment, with some needing additional basal insulin. GLP1 agonists should be used as second-line agents once early ketosis and symptoms are controlled. Glycaemic control improves microvascular but not cardiovascular risk. Reduction in excess adiposity, smoking prevention, increased physical activity and reduction of hypertension and dyslipidaemia are essential to reduce major adverse cardiovascular events. CONCLUSIONS: This evidence-based guideline aims to provide a practical approach in managing this condition in the UK.

Metformin suppresses NFE2L1 pathway activation to inhibit gap junction beta protein expression in NSCLC.

OBJECTIVE: Non-small-cell lung cancer (NSCLC) is a deadly form of cancer that exhibits extensive intercellular communication which contributed to chemoradiotherapy resistance. Recent evidence suggests that arrange of key proteins are involved in lung cancer progression, including gap junction proteins (GJPs). METHODS AND RESULTS: In this study, we examined the expression patterns of GJPs in NSCLC, uncovering that both gap junction protein, beta 2 (GJB2) and gap junction protein, beta 2 (GJB3) are increased in LUAD and LUSC. We observed a correlation between the upregulation of GJB2, GJB3 in clinical samples and a worse prognosis in patients with NSCLC. By examining the mechanics, we additionally discovered that nuclear factor erythroid-2-related factor 1 (NFE2L1) had the capability to enhance the expression of connexin26 and connexin 31 in the NSCLC cell line A549. In addition, the use of metformin was discovered to cause significant downregulation of gap junction protein, betas (GJBs) by limiting the presence of NFE2L1 in the cytoplasm. CONCLUSION: This emphasizes the potential of targeting GJBs as a viable treatment approach for NSCLC patients receiving metformin.

Predictive factors and the management of hyperglycemia in patients with acromegaly and Cushing's disease receiving pasireotide treatment: post hoc analyses from the SOM230B2219 study.

Introduction: Pasireotide, a somatostatin receptor ligand, is approved for treating acromegaly and Cushing's disease (CD). Hyperglycemia during treatment can occur because of the drug's mechanism of action, although treatment discontinuation is rarely required. The prospective, randomized, Phase IV SOM230B2219 (NCT02060383) trial was designed to assess optimal management of pasireotide-associated hyperglycemia. Here, we investigated predictive factors for requiring antihyperglycemic medication during pasireotide treatment. Methods: Participants with acromegaly or CD initiated long-acting pasireotide 40 mg/28 days intramuscularly (acromegaly) or pasireotide 600 µg subcutaneously twice daily during pre-randomization (≤16 weeks). Those who did not need antihyperglycemic medication, were managed with metformin, or received insulin from baseline entered an observational arm ending at 16 weeks. Those who required additional/alternative antihyperglycemic medication to metformin were randomized to incretin-based therapy or insulin for an additional 16 weeks. Logistic-regression analyses evaluated quantitative and qualitative factors for requiring antihyperglycemic medication during pre-randomization. Results: Of 190 participants with acromegaly and 59 with CD, 88 and 15, respectively, did not need antihyperglycemic medication; most were aged <40 years (acromegaly 62.5%, CD 86.7%), with baseline glycated hemoglobin (HbA1c) <6.5% (<48 mmol/mol; acromegaly 98.9%, CD 100%) and fasting plasma glucose (FPG) <100 mg/dL (<5.6 mmol/L; acromegaly 76.1%, CD 100%). By logistic regression, increasing baseline HbA1c (odds ratio [OR] 3.6; P=0.0162) and FPG (OR 1.0; P=0.0472) and history of diabetes/pre-diabetes (OR 3.0; P=0.0221) predicted receipt of antihyperglycemic medication in acromegaly participants; increasing baseline HbA1c (OR 12.6; P=0.0276) was also predictive in CD participants. Investigator-reported hyperglycemia-related adverse events were recorded in 47.9% and 54.2% of acromegaly and CD participants, respectively, mainly those with diabetes/pre-diabetes. Conclusion: Increasing age, HbA1c, and FPG and pre-diabetes/diabetes were associated with increased likelihood of requiring antihyperglycemic medication during pasireotide treatment. These risk factors may be used to identify those who need more vigilant monitoring to optimize outcomes during pasireotide treatment.

Metformin Loaded Zein Polymeric Nanoparticles to Augment Antitumor Activity against Ehrlich Carcinoma via Activation of AMPK Pathway: D-Optimal Design Optimization, In Vitro Characterization, and In Vivo Study.

Metformin (MET), an antidiabetic drug, is emerging as a promising anticancer agent. This study was initiated to investigate the antitumor effects and potential molecular targets of MET in mice bearing solid Ehrlich carcinoma (SEC) as a model of breast cancer (BC) and to explore the potential of zein nanoparticles (ZNs) as a carrier for improving the anticancer effect of MET. ZNs were fabricated through ethanol injection followed by probe sonication method. The optimum ZN formulation (ZN8) was spherical and contained 5 mg zein and 30 mg sodium deoxycholate with a small particle size and high entrapment efficiency percentage and zeta potential. A stability study showed that ZN8 was stable for up to three months. In vitro release profiles proved the sustained effect of ZN8 compared to the MET solution. Treatment of SEC-bearing mice with ZN8 produced a more pronounced anticancer effect which was mediated by upregulation of P53 and miRNA-543 as well as downregulation of NF-κB and miRNA-191-5p gene expression. Furthermore, ZN8 produced a marked elevation in pAMPK and caspase-3 levels as well as a significant decrease in cyclin D1, COX-2, and PGE2 levels. The acquired findings verified the potency of MET-loaded ZNs as a treatment approach for BC.

Metformin: A Dual-Role Player in Cancer Treatment and Prevention.

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.

Metformin and risk of hematological cancers in patients with diabetes: a systematic review and meta-analysis.

FUNDING: No external funding.

Respiratory complex I regulates dendritic cell maturation in explant model of human tumor immune microenvironment.

BACKGROUND: Combining cytotoxic chemotherapy or novel anticancer drugs with T-cell modulators holds great promise in treating advanced cancers. However, the response varies depending on the tumor immune microenvironment (TIME). Therefore, there is a clear need for pharmacologically tractable models of the TIME to dissect its influence on mono- and combination treatment response at the individual level. METHODS: Here we establish a patient-derived explant culture (PDEC) model of breast cancer, which retains the immune contexture of the primary tumor, recapitulating cytokine profiles and CD8+T cell cytotoxic activity. RESULTS: We explored the immunomodulatory action of a synthetic lethal BCL2 inhibitor venetoclax+metformin drug combination ex vivo, discovering metformin cannot overcome the lymphocyte-depleting action of venetoclax. Instead, metformin promotes dendritic cell maturation through inhibition of mitochondrial complex I, increasing their capacity to co-stimulate CD4+T cells and thus facilitating antitumor immunity. CONCLUSIONS: Our results establish PDECs as a feasible model to identify immunomodulatory functions of anticancer drugs in the context of patient-specific TIME.

Correlation between anti-müllerian hormone in polycystic ovarian syndrome with metformin: a systematic review and meta-analysis.

OBJECTIVE: This study aims to examine the short-term effects of oral metformin (MET) on serum anti-müllerian hormone (AMH) levels and to verify its impact on AMH concentrations in women with polycystic ovary syndrome (PCOS). METHODS: The literature search, extending from January 2000 to April 2023, was conducted using databases such as PubMed, Embase, and the Cochrane Central, resulting in the inclusion of 20 studies. These selected studies, evaluated for quality using the Newcastle-Ottawa Scale, investigated changes in AMH levels before and after treatment, with durations ranging from less than three months to over six months. The reported outcomes were quantified as standardized mean differences (SMD) with 95% confidence intervals (CI). This comprehensive systematic review and meta-analysis was registered with the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42023420705. The statistical analyses were performed using Review Manager 5.4.1. RESULTS: ① The study incorporated 20 articles, consisting of 12 prospective studies, 7 randomized controlled trials (RCT), and 1 cross-sectional study. ② Serum AMH levels in patients with PCOS diminish subsequent to the oral administration of MET. ③ Across the spectrum of studies analyzed, a pronounced degree of heterogeneity is evident, potentially ascribed to differential parameters including body mass index (BMI), daily pharmacological dosages, the temporal extent of treatment regimens, criteria of PCOS, and detection Methods. ④ The impact of MET on AMH levels exhibits a dose-responsive trend, with escalating doses of MET being associated with progressively greater declines in AMH concentrations in the patient population. ⑤ For women with PCOS receiving MET therapy, a minimum treatment duration of three months may be necessary to observe a reduction in serum AMH levels. CONCLUSIONS: The results of this meta-analysis indicate that MET treatment exerts a suppressive effect on serum AMH levels in women with PCOS. It appears that a treatment duration of at least three months is required to achieve a significant decrease in AMH concentrations. Furthermore, the influence of MET on AMH is dose-dependent, with higher doses correlating with more pronounced reductions in AMH levels among the patients studied.

Effects of quercetin on polycystic ovary syndrome in animal models: a systematic review and meta-analysis.

BACKGROUND: Metformin is an insulin sensitizer that is widely used for the treatment of insulin resistance in polycystic ovary syndrome patients. However, metformin can cause gastrointestinal side effects. PURPOSE: This study showed that the effects of quercetin are comparable to those of metformin. Therefore, this study aimed to systematically evaluate the efficacy of quercetin in treating PCOS. METHODS: The present systematic search of the Chinese National Knowledge Infrastructure (CNKI), Wanfang Data Information Site, Chinese Scientific Journals Database (VIP), SinoMed, Web of Science, and PubMed databases was performed from inception until February 2024. The methodological quality was then assessed by SYRCLE's risk of bias tool, and the data were analyzed by RevMan 5.3 software. RESULTS: Ten studies were included in the meta-analysis. Compared with those in the model group, quercetin in the PCOS group had significant effects on reducing fasting insulin serum (FIS) levels (P = 0.0004), fasting blood glucose (FBG) levels (P = 0.01), HOMA-IR levels (P < 0.00001), cholesterol levels (P < 0.0001), triglyceride levels (P = 0.001), testosterone (T) levels (P < 0.00001), luteinizing hormone (LH) levels (P = 0.0003), the luteinizing hormone/follicle stimulating hormone (LH/FSH) ratio (P = 0.01), vascular endothelial growth factor (VEGF) levels (P < 0.00001), malondialdehyde (MDA) levels (P = 0.03), superoxide dismutase (SOD) levels (P = 0.01) and GLUT4 mRNA expression (P < 0.00001). CONCLUSION: This meta-analysis suggested that quercetin has positive effects on PCOS treatment. Quercetin can systematically reduce insulin, blood glucose, cholesterol, and triglyceride levels in metabolic pathways. In the endocrine pathway, quercetin can regulate the function of the pituitary-ovarian axis, reduce testosterone and luteinizing hormone (LH) levels, and lower the ratio of LH to follicle-stimulating hormone (FSH). Quercetin can regulate the expression of the GLUT4 gene and has antioxidative effects at the molecular level.

Energy metabolism as therapeutic target for aged wound repair by engineered extracellular vesicle.

Aging skin, vulnerable to age-related defects, is poor in wound repair. Metabolic regulation in accumulated senescent cells (SnCs) with aging is essential for tissue homeostasis, and adequate ATP is important in cell activation for aged tissue repair. Strategies for ATP metabolism intervention hold prospects for therapeutic advances. Here, we found energy metabolic changes in aging skin from patients and mice. Our data show that metformin engineered EV (Met-EV) can enhance aged mouse skin repair, as well as ameliorate cellular senescence and restore cell dysfunctions. Notably, ATP metabolism was remodeled as reduced glycolysis and enhanced OXPHOS after Met-EV treatment. We show Met-EV rescue senescence-induced mitochondria dysfunctions and mitophagy suppressions, indicating the role of Met-EV in remodeling mitochondrial functions via mitophagy for adequate ATP production in aged tissue repair. Our results reveal the mechanism for SnCs rejuvenation by EV and suggest the disturbed energy metabolism, essential in age-related defects, to be a potential therapeutic target for facilitating aged tissue repair.

[Metformin suppresses hypoxia-inducible factor-1α expression in cancer-associated fibroblasts to block tumor-stromal cross-talk in breast cancer].

OBJECTIVE: To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer. METHODS: Tumor associated fibroblasts (CAFs) co-cultured with breast cancer cells were treated with metformin, and the changes in expressions of hypoxia-inducible factor-1α (HIF-1α), p-AMPK, stroma-derived factor-1 (SDF-1) and interleukin-8 (IL-8) in the CAFs were detected using ELISA, RT-qPCR or Western blotting; Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1, IL-8 and TGF-ß1. The effects of HIF-1α shRNA or overexpression plasmid, AMPK shRNA, and treatment with OG (a proline hydroxylase inhibitor) or 2-OXO (a proline hydroxylase activator) were examined on p-AMPK, HIF-1α, SDF-1 and IL-8 expressions and invasiveness of the CAFs. RESULTS: Metformin treatment significantly increased the expression levels of p-AMPK, SDF-1 and IL-8 (P<0.05) and decreased HIF-1α expression (P<0.05) without affecting AMPK expression level (P>0.05) in the CAFs. The invasion ability of metformintreated breast cancer cells was significantly decreased (P<0.05). Exogenous SDF-1 and IL-8, HIF-1α overexpression, and OGinduced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion (P<0.05) and HIF-1α, SDF-1 and IL-8 expressions in CAFs (P<0.05). Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells (P<0.05). P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells (P<0.05). Treatment with TGF-ß1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells (P<0.05). CONCLUSION: Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.

IMPACT OF METFORMIN ON OSTEOPROTEGERIN LEVELS IN POLYCYSTIC OVARIAN WOMEN.

Metformin is an important agent in the treatment of polycystic ovary syndrome (PCOS) treatment. Osteoblast express osteoprotegerin (OPG) which has integral effects on bone metabolism nexus. This cross-sectional research sought to identify the impact of metformin therapy on serum level osteoblast express osteoprotegerin and prolactin in women with polycystic ovary syndrome. Methods: 30 patients with PCOS and 30 controls. The current study revealed that prolactin levels were increased in PCOS group compared to control group which is highly significant. While after treatment with metformin prolactin level was reduced significantly in than before treatment. Osteoprotegerin concentrations were considerably dropped in the PCOS group contrasted with the control group. Conversely, serum osteoprotegerin in metformin-treated group were higher compared to PCOS group. Osteoblast express osteoprotegerin level increased after 3 months of treatment with metformin in women with polycystic ovary syndrome.

Effectiveness of metformin to pregnant women with PCOS to reduce spontaneous abortion and gestational diabetes mellitus: a protocol for an overview of reviews.

INTRODUCTION: Polycystic ovary syndrome (PCOS) is a globally prevalent endocrinological disorder and has been associated with poor pregnancy outcomes, including a higher rate of gestational diabetes and miscarriage. Metformin is among the drugs investigated to improve the prognosis of pregnant women with PCOS. OBJECTIVE: To conduct an overview of systematic reviews examining the effects of metformin versus placebo or no intervention throughout pregnancy among pregnant women with a preconception PCOS diagnosis to reduce the incidence of miscarriage and gestational diabetes. METHODS AND ANALYSIS: We will perform an overview of systematic reviews by searching Embase, PubMed, Virtual Health Library, Cochrane Central Register of Controlled Trials, Trip Database, Scopus, Web of Science and Cumulative Index to Nursing and Allied Health Literature from inception to 17 August 2023. Language, publication status and year indexed or published filters will not be applied. Two reviewers will independently screen and select papers, assess their quality, evaluate their risk of bias and collect the data. The included reviews will be summarised narratively. The quality and risk of bias of the systematic review and meta-analysis studies included will be assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, Second Version) and ROBIS (Risk of Bias in Systematic Reviews), respectively. ETHICS AND DISSEMINATION: This overview of reviews will analyse data from systematic reviews on the use of metformin for prepregnancy diagnosis of PCOS to reduce adverse outcomes. As there will be no primary data collection, a formal ethical analysis is unnecessary. The study outcomes will be submitted to a peer-reviewed journal and presented at conferences. PROSPERO REGISTRATION NUMBER: CRD42023441488.

Role of monocarboxylate transporters in AMPK-mediated protection against excitotoxic injury in the rat retina.

Activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway protects against N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinal injury. AMPK activation enhances fatty acid metabolism and ketone body synthesis. Ketone bodies are transported into neurons by monocarboxylate transporters (MCTs) and exert neuroprotective effects. In this study, we examined the distribution and expression levels of MCT1 and MCT2 in the retina and analyzed the effects of pharmacological inhibition of MCTs on the protective effects of metformin and 5-aminoimidazole-4-carboxamide (AICAR), activators of AMPK, against NMDA-induced retinal injury in rats. MCT1 was expressed in the blood vessels, processes of astrocytes and Müller cells, and inner segments of photoreceptors in the rat retina, whereas MCT2 was expressed in neuronal cells in the ganglion cell layer (GCL) and in astrocyte processes. The expression levels of MCT2, but not MCT1, decreased one day after intravitreal injection of NMDA (200 nmol). Intravitreal injection of NMDA decreased the number of cells in the GCL compared to the vehicle seven days after injection. Simultaneous injection of metformin (20 nmol) or AICAR (50 nmol) with NMDA attenuated NMDA-induced cell loss in the GCL, and these protective effects were attenuated by AR-C155858 (1 pmol), an inhibitor of MCTs. AR-C155858 alone had no significant effect on the retinal structure. These results suggest that AMPK-activating compounds protect against NMDA-induced excitotoxic retinal injury via mechanisms involving MCTs in rats. NMDA-induced neurotoxicity may be associated with retinal neurodegenerative changes in glaucoma and diabetic retinopathy. Therefore, AMPK-activating compounds may be effective in managing these retinal diseases.

Effect of metformin on anti-mullerian hormone levels in women with polycystic ovarian syndrome: a systematic review and meta-regression analysis of randomized controlled trials with.

BACKGROUND: Several interventional studies have evaluated the potential anti-Mullerian hormone (AMH)-reduction effect of metformin. However, the results are still contradictory. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of metformin on AMH in the women with with polycystic ovarian syndrome (PCOS). METHODS: Scopus, PubMed/Medline, Web of Science, Cochrane, and Embase databases were searched using standard keywords to identify all controlled trials investigating the AMH levels following metformin administration. Pooled weighted mean difference and 95% confidence intervals were achieved by random-effects model analysis for the best estimation of outcomes. RESULTS: Sixteen studies with 484 participants' were included in this article. The pooled findings showed that AMH levels in the single arm clinical trials were significantly reduced (pooled WMD of -3.06 ng/ml; 95% confidence interval [CI] -4.03 to -2.10; P < 0.001) after use of metformin. Furthermore, compared to the control group, in randomized clinical trials, a reduced significant effect on AMH levels was observed following use of metformin (pooled WMD of -3.47 ng/ml; 95% CI -7.14 to -0.19; P = 0.047). Furthermore, higher reduction in the AMH levels with a metformin dosage ≤ 1500 mg/day and duration of treatment ≤ 12 weeks when compared to higher dosages and duration of intervention, observed in this meta-analysis. CONCLUSIONS: In conclusion, results this meta-analysis of clinical trials confirms the beneficial effect of the treatment with metformin in the reduction of the AMH levels in women.