ObjectiveTo observe the effect of metformin on airway remodeling in asthma and its possible mechanism.MethodsTwenty-eight B/N rats were randomly divided into control group, asthma group, metformin intervention group and rapamycin intervention group. After that, the asthma model was established and intervened with metformin and rapamycin. The airway resistance and airway reactivity were measured 48 hours after the last challenge, and then the lung tissue samples were collected. Histopathological examination was used to observe airway inflammatory cell infiltration, goblet cell proliferation, airway wall fibrosis and remodeling, as well as airway smooth muscle proliferation. The expression of AMPK/mTOR pathway related proteins was detected by Western blot.ResultsCompared with the asthma group, metformin and rapamycin significantly reduced the airway responsiveness induced by high concentration of acetylcholine (P<0.05), reduced the infiltration of inflammatory cells in lung tissue and the changes of airway wall structure (P<0.05), reduced goblet cell proliferation in airway epithelium, collagen fiber deposition in lung tissue and bronchial smooth muscle hyperplasia (P<0.05). Further studies showed that the effects of metformin and rapamycin were related to AMPK/mTOR pathway. Compared with the asthma group, metformin and rapamycin could significantly reduce the expression of p-mTOR, p-p70s6k1 and SKP2, while p21 protein expression was significantly increased (P<0.05). In addition, metformin and rapamycin had similar effects (P>0.05).ConclusionMetformin can alleviate airway hyperresponsiveness and airway remodeling by activating AMPK and then inhibiting mTOR pathway, which may be a potential drug for treating asthma and preventing airway remodeling.
Objective To formulate an evidence-based treatment plan for a patient with gestational diabetes mellitus. Methods Based on the clinical questions raised from a real-life patient of gestational diabetes mellitus, we searched ACP Journal Club (1991 to Dec. 2006), The Cochrane Library (Issue 4, 2006), MEDLINE (1966 to Dec. 2006) and Chinese Biological Medical Database (1980 to Dec. 2006) for systematic reviews, randomized controlled trials, cohort and case-control studies. We used the following keywords: gestational diabetes, metformin, and pregnancy complication. The quality of the included studies was assessed.Results One meta-analysis (from MEDLINE) and two randomized controlled trials (from the Cochrane Central Register of Controlled Trials) were included. These studies concluded that there was no clear evidence on the benefits of metformin for gestational diabetes. Based on the current evidence, integrated with clinical expertise and the patient’s values, metformin was not used for this patient. Instead, intensive dietary control, blood glucose control, and appropriate exercise were administered. After this individual treatment, the patient gave birth to a healthy baby in 39+4 Weeks. Conclusion The appropriate management for gestational diabetes mellitus has been formulated with the approach of evidence-based medicine. Large-scale, methodologically-sound trials are required.
ObjectiveTo observe the effect of metformin on the polarization state and photoreceptor cell activity of microglia (BV2 cells) in a high glucose environment. MethodsAn experimental study. BV2 cells were divided into a control group, a high glucose group, and a metformin+high glucose group. The cells in the high glucose group were cultured with 75 mmol/L glucose in the medium; the cells in the metformin+high glucose group were pretreated with 2 mmol/L metformin for 12 h and then placed in 75 mmo/L glucose concentration medium. The relative expression of M1 marker inducible nitric oxide synthase (iNOS), CD86 and M2 markers arginase 1 (Arg-1), and CD206 protein were detected by Western blot. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-4 were detected by enzyme-linked immunosorbent assay (ELISA). BV2 cells were co-cultured with mouse retinal photoreceptor cells (661W cells) for 24 h. The proliferation rate of 661W cells in each group was measured by methyl thiazolyl tetrazolium (MTT) colorimetric assay; the apoptosis rate of 661W cells in each group was measured by flow cytometry and terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL). An independent sample t-test was used for comparison between groups. ResultsWestern blot assay showed that the relative expression of iNOS and CD86 protein was increased and the relative expression of Arg-1 and CD206 protein was decreased in BV2 cells in the high glucose group compared with the control group, and the differences were all statistically significant (t=－16.783, －11.605, 4.325, 4.649; P＜0.05); compared with the high glucose group, the relative expression of iNOS and CD86 protein was decreased and the relative expression of Arg-1 and CD206 protein was increased in BV2 cells in the metformin + high glucose group compared with the high glucose group, and the differences were all statistically significant (t=7.231, 5.560, －8.035, －8.824; P＜0.01). ELISA results showed that compared with the control group, the BV2 cells in the high glucose group had increased IL-6, TNF-α content and IL-4 content was decreased in BV2 cells in the high glucose group compared with the control group, and the differences were all statistically significant (t=－64.312, －127.147, 71.547; P＜0.001); compared with the high glucose group, IL-6 and TNF-α content was significantly decreased and IL-4 content was significantly increased in BV2 cells in the metformin+high glucose group, and the differences were all statistically significant (t=44.426, 83.232, －143.115; P＜0.001). After co-culture of BV2 cells with 661W cells for 24 h, the results of MTT colorimetric assay showed that compared with the control group, the activity of 661W cells in the high glucose group was significantly reduced, and the difference was statistically significant (t=7.456, P＜0.01); compared with the high glucose group, the activity of 661W cells in the metformin+high glucose group was increased (t=－3.076, P＜0.05). TUNEL method and flow cytometry showed that the apoptosis rate of 661W cells in the high glucose group was significantly higher compared with the control group, and the differences were both statistically significant (t=－22.248, －22.628; P＜0.001); compared with the high glucose group, the apoptosis rate of 661W cells in the metformin+high glucose group was significantly decreased, and the difference was statistically significant (t=11.767, 6.906; P＜0.001, 0.01). ConclusionIn the high glucose environment, metformin inhibited the inflammatory response and attenuated the apoptosis of photoreceptor cells by regulating the polarization of microglia toward the M2 type.
Objective To observe the synergistic effect of metformin and anti-vascular endothelial growth factor (VEGF) in the treatment of diabetic retinopathy. Methods This study was composed of clinical data review and in vitro cell experiment. Ten patients (12 eyes) with diabetic macular edema treated with anti-VEGF drugs were included in the study. Patients were randomly divided into the VEGF group (anti-VEGF drug therapy) and the combined treatment group (anti-VEGF drug combined with metformin). The changes of visual acuity and central retinal thickness (CRT) were compared between the two groups. As far as the in vitro experiment was concerned, vascular endothelial cells were divided into the control group (normal cells), the VEGF group (50 ng/ml VEGF), the anti-VEGF group (50 ng/ml VEGF+2.5 μg/ml of conbercept), and the combined group (50 ng/ml VEGF +2.5 μg/ml of conbercept +2.0 mmol/L of metformin). And then MTT cell viability assay, scratch assay and real-time quantitative polymerase chain reaction assay were performed to analyze the cell viability, cell migration and mRNA level of VEGFR2, protein kinase C (PKC)-α and PKC-β successively. ResultsReview of clinical trial shows that the CRT recovery rates in the combined treatment group were much higher than that in the VEGF group at 3 month after the operation, while the difference was statistically significant (t=−2.462, P＜0.05). In vitro cell experiment results showed that VEGF induction upregulated the viability and mobility of vascular endothelial cells obviously compared with control group, at the same time, the use of anti VEGF drugs can effectively reverse the trend, in contrast, combination of metformin and anti-VEGF showed a more superior effect to some extent (P＜0.05). In the VEGF group, the mRNA expression of VEGFR2, PKC-αand PKC-β were significantly increased compared with the control group (P＜0.01); while the mRNA expression of VEGFR2, PKC-αand PKC-β in the combination group decreased significantly compared with the VEGF group and the control group (P＜0.05). However, in the anti-VEGF group, the mRNA expression of VEGFR2, PKC-αand PKC-β were decreased, but has failed to reach the level of statistical learn the difference. ConclusionsThe combination of metformin and anti-VEGF drugs can reduce the CRT of diabetic retinopathy patients and inhibit the proliferation and migration of retinal vascular endothelial cells which induced by VEGF. The synergistic mechanism may be related to the inhibitory effect of metformin on the expression of VEGFR and PKC.
ObjectiveTo understand the role of metformin on reducing incidence of type 2 diabetes mellitus (T2MD) patients complicated with liver cancer. MethodThe related literatures of metformin treated patients with T2MD complicated with liver cancer at home and abroad in recent years were reviewed. ResultsA large number of epidemiological and clinical data showed that the metformin might prevent the occurrence of the T2MD patients complicated with liver cancer, its mechanism was mainly inhibited the proliferation of hepatoma cells through the ATM-LKB1-AMPK-mTOR pathway, PI3K/Akt/mTOR pathway, or miRNA. The current controversy was the authenticity of the data, the influencing factors included the aging problem and characteristics of metformin user. The prospective study design rigorous remained to be clarified. ConclusionMetformin could reduce the incidence of T2MD patients complicated with liver cancer, and could inhibit the growth of liver cancer cells, which provides a new way of thinking for the comprehensive treatment of liver cancer.
Objective To assess the effects and safety of sitagliptin combined with metformin in treating type 2 diabetes mellitus. Methods The Cochrane Library, PubMed, EMbase, CNKI, WanFang Data, VIP and CBM were searched to collect the randomized controlled trials (RCTs) on sitagliptin combined with metformin in treating Type 2 diabetes mellitus (T2DM) from inception to November, 2012. References of included studies were also retrieved. Two reviewers independently screened studies according to exclusion and inclusion criteria, extracted data, and assessed the methodological quality. Then, meta-analysis was performed using RevMan 5.1 software. Results 7 RCTs involving 2 917 patients were included. The results of meta-analysis showed that, compared with metformin alone, sitagliptin combined with metformin effectively improved HbA1c levels (WMD= –0.62%, 95%CI –0.76 to –0.47, Plt;0.000 1) and fasting plasma glucose levels (WMD= –0.7 mmol/L, 95%CI –1.03 to –0.37, Plt;0.000 01), and increased insulin sensitivity and β-cell function. But there was no significant difference between the two groups in the incidences of gastrointestinal reactions and hypoglycemia. Conclusion Compared with using metformin alone, sitagliptin combined with metformin can improve glycemic control, enhance insulin sensitivity and better β-cell function more effectively and both have a similar effect on weight lose, but there is no significant difference he incidences of gastrointestinal reactions and hypoglycemia. The above conclusion should be verified by more large-scale high-quality studies in future due to the limitations of the methodological quality and sample size of the included studies.
ObjectiveTo explore the relationship between metformin use and the risk and prognosis of esophageal cancer in patients with diabetes.MethodsThe PubMed, Web of Science, EMbase, VIP, WanFang and CNKI databases were searched by computer to identify relevant studies from inception to August 21, 2021. Newcastle-Ottawa scale (NOS) was used to evaluate research quality. The STATA 12.0 software was used to conduct the statistical analysis.ResultsA total of 14 studies involving 5 605 218 participants were included finally. NOS of all researches were≥6 points. The pooled results indicated that metformin use could decrease the risk of esophageal cancer in diabetics (OR=0.84, 95%CI 0.71-1.00, P=0.045), and could also prolong the overall survival of diabetics with esophageal cancer (HR=0.89, 95%CI 0.80-0.99, P=0.025).ConclusionMetformin use can not only decrease the risk of esophageal cancer in patients with diabetes, but also improve the prognosis of diabetics with esophageal cancer significantly. However, more prospective high-quality studies are still needed to verify the conclusion.
Objectives To assess the efficacy and safety of metformin plus rosiglitazone in treating type 2 diabetes mellitus. Methods Based on the principles and methods of Cochrane systematic reviews, we searched the CochraneLibrary (2008, 4 issue), PubMed (1966 to October 19, 2008), Embase (1974 to October 19, 2008), China BiomedicalLiterature Database (1978 to October 12, 2008), China Journal Fulltext Database (1994 to October 12, 2008), ChineseScientific Journals Full text Database (1989 to October 12, 2008). Randomized controlled trials (RCTs) of Metforminplus roziglitazone versus metformin for type 2 diabetes were included. We assessed the quality of the included RCTsaccording to the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.1. The Cochrane Collaboration’s software RevMan 5.0 was used for meta-analysis. Results Twelve RCTs totaling 3020 patients were included. Metaanalysis showed that Glycosylated hemoglobin levels [WMD= – 0.48%, 95%CI (– 0.74, – 0.22), P=0.000 3], fasting plasma glucose levels [WMD= – 1.03mmol/L, 95%CI (– 1.85, – 0.75), Plt;0.000 01], insulin sensitivity, and β-cell function improved significantly with metformin plus rosiglitazone therapy. Compared with the metformin monotherapy group, patients treated with metformin plus rosiglitazone had more edema events [RR= 3.27, 95%CI (1.80, 5.91), Plt;0.000 1] and lower gastro-intestinal events [RR= 0.82, 95%CI (0.71, 0.94), P=0.004]. We found no statistically significant effect on body weight, the percentage of patients with at least one adverse event, and hypoglycemia events. Conclusions Current evidence demonstrates that combination treatment with metformin plus rosiglitazone improves glycemic control, insulin sensitivity, and cells function more effectively than with metformin monotherapy. Side effects of two types of therapy have differences in performance.
Objective To observe the effect of metformin (Met) on inflammatory bodies and focal death in human retinal microvascular endothelial cells (hRMEC) in diabetes mellitus (DM) microenvironment. MethodsExperimental research was divided into in vivo animal experiment and in vitro cell experiment. In vivo animal experiments: 9 healthy C57BL/6J male mice were randomly divided into DM group, normal control group, and DM+Met group, with 3 mice in each group. DM group and DM+Met group mice were induced by streptozotocin to establish DM model, and DM+Met group was given Met 400 mg/ (kg · d) intervention. Eight weeks after modeling, the expression of NLRP3, cleaved-membrane perforating protein D (GSDMD) and cleaved-Caspase-1 in the retina of mice in the normal control group, DM group and DM+Met group were observed by immunohistochemical staining. In vitro cell experiments: hRMEC was divided into conventional culture cell group (N group), advanced glycation end products (AGE) group, and AGE+Met group. Joining the AGE, AGE+Met groups cells were induced by 150 μg/ml of glycation end products, and 2.0 mmol/L Met was added to the AGE+Met group. Pyroptosis was detected by flow cytometry; 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe was used to detect the expression of reactive oxygen species (ROS) in cells of each group. Real-time fluorescence quantitative polymerase chain reaction and Western blot were used to detect the relative mRNA and protein expression levels of NLRP3, cleaved-GSDMD, cleaved-Caspase-1 in each group of cells. Single factor analysis of variance was used for comparison among the three groups. ResultsIn vivo animal experiments: compared with the DM group, the expression of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in the retina of normal control group and DM+Met group mice was significantly reduced, with significant difference among the 3 groups (F=43.478, 36.643, 24.464; P＜0.01). In vitro cell experiment and flow cytometry showed that the pyroptosis rate of AGE group was significantly higher than that of N group and AGE+Met group (F=32.598, P＜0.01). The DCFH-DA detection results showed that the intracellular ROS levels in the N group and AGE+Met group were significantly lower than those in the AGE group, with the significant difference (F=47.267, P＜0.01). The mRNA (F=51.563, 32.192, 44.473; P＜0.01) and protein levels (F=63.372, 54.463, 48.412; P＜0.01) of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in hRMEC of the AGE+Met group were significantly reduced compared to the N group. ConclusionMet can down regulate the expression of NLRP3 inflammatory body related factors in hRMEC and inhibit pyroptosis.
Objective To explore the role of estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) in estrogen-induced proliferation of endometrial cancer, and explore whether metformin inhibits the proliferation of endometrial cancer cells through ERα and ERβ. Methods Stable transfected Ishikawa cells were constructed by lentivirus. The effects of down-regulated ERα and ERβ on estrogen-induced Ishikawa cell proliferation were detected by methyl thiazolyl tetrazolium assay. The effects of down-regulated ERα and ERβ on estrogen-induced Ishikawa cell cycle were detected by flow cytometry. In addition, quantitative real-time polymerase chain reaction and Western blotting assays were used to detect changes in the expression of cyclinD1 and P21 involved in cell cycle regulation. The effects of down-regulated ERα and ERβ on estrogen-induced Ishikawa cell proliferation were observed by adding metformin to estrogen treatment. Results Down-regulation of ERα inhibited the proliferation and cell cycle of Ishikawa cells (P<0.05). Down-regulation of ERα also inhibited the expression of cyclinD1 and promoted the expression of P21 (P<0.05). Down-regulation of ERα counteracted the effect of estrogen-induced cell proliferation, cell cycle, and the expression changes of cyclinD1 and P21 (P<0.05). Down-regulation of ERβ promoted the proliferation and cell cycle of Ishikawa cells (P<0.05). Down-regulation of ERβ also promoted the expression of cyclinD1 and inhibited the expression of P21 (P<0.05). Down-regulation of ERβ enhanced the effect of estrogen-induced cell proliferation, cell cycle, and the expression changes of cyclinD1 and P21 (P<0.05). Metformin inhibited the proliferation of estrogen-induced Ishikawa cells (P<0.05), while in the down-regulated ERα Ishikawa cells or down-regulated ERβ Ishikawa cells, the inhibition of metformin on Ishikawa cells disappeared (P<0.05). Conclusions ERα may promote estrogen-induced proliferation of endometrial cancer cells, while ERβ may inhibit estrogen-induced proliferation of endometrial cancer cells. In addition, ERα and ERβ may also mediate the inhibitory effect of metformin on endometrial cancer cells.