Síndrome metabólico, metformina y hueso / Metabolic syndrome, metformin and bone

El síndrome metabólico se define como un trastorno heterogéneo y multifactorial con riesgo cardiovascular elevado. Actualmente se encuentra en franco crecimiento debido al sedentarismo y la ingesta rica en grasas y azúcares. Su tratamiento incluye la indicación de cambios en el estilo de vida, con realización de actividad física y una alimentación saludable e hipocalórica. Cuando esto no es eficaz, se pueden utilizar diferentes fármacos, y entre los más prescriptos se encuentra la metformina, caracterizada por su acción insulino-sensibilizante. Numerosos trabajos han estudiado la vinculación del síndrome metabólico con el tejido óseo. Se demostró como resultado general, aunque no concluyente, que dicho síndrome se asocia con una disminución de la densidad mineral ósea y un aumento en la incidencia de fracturas osteoporóticas. Una de las limitaciones de estos estudios clínicos estaría ligada a la gran heterogeneidad de los pacientes con síndrome metabólico. Por otra parte, y dado que diversos estudios preclínicos han sugerido posibles acciones osteogénicas de la metformina, se ha investigado el posible efecto óseo de un tratamiento con este fármaco en personas con hiperglucemia o disglucemia. Varios estudios clínicos muestran que este efecto sería nulo o, en algunos casos, de carácter protector para el sistema óseo. No obstante, se debería tener precaución en el uso de dicho fármaco en pacientes que necesiten dosis altas y/o posean riesgo elevado de fractura, ya que sus altas concentraciones podrían tener consecuencias negativas sobre el metabolismo óseo. (AU)

Metabolic syndrome is defined as a heterogeneous and multifactorial disorder with high cardiovascular risk. Its incidence is currently growing due to sedentary lifestyles and diets with a high intake of fats and sugars. Treatment for metabolic syndrome begins with changes in lifestyle, such as physical activity and a healthy and hypocaloric diet. When this is not effective, different drugs can be used, and one of the most frequently prescribed is the insulin-sensitizer metformin. Numerous investigations have evaluated the possible link between metabolic syndrome and alterations in bone metabolism. Although not conclusive, most clinical studies point to an association between metabolic syndrome, a decrease in bone mineral density and an increase in the incidence of osteoporotic fractures. However, an important limitation of these studies is the great heterogeneity of individuals with metabolic syndrome. In view of preclinical research indicating possible osteogenic actions of metformin, the effects on bone of metformin has been evaluated in patients with hyperglycemia. Most studies have found either no effect on fracture incidence, or a mild protective action. However, since elevated concentrations of metformin might negatively affect bone metabolism, caution should be taken when prescribing this drug for patients who require high doses, and/or have an excess fracture risk. (AU)

Gingko biloba extract improves the lipid profile, inflammatory markers, leptin level and the antioxidant status of T2DM patients poorly responding to metformin: A double- blind, randomized, placebo-controlled trial

Abstract The present study aims to evaluate the effects of Ginkgo biloba (GKB) extract as "add- on" therapy with metformin on the lipid profile, inflammatory markers, leptin and the total antioxidant capacity (TAOC) of patients with type 2 diabetes mellitus (T2DM). It is a multi- center, randomized, placebo-controlled double-blinded clinical study. Sixty patients were allocated into two groups: control and treatment groups; they received orally either 120 mg starch/capsule or 120mg GKB/capsule, respectively as an adjuvant with metformin for 90 days. Blood samples were obtained at zero time and after 90 days. The blood was utilized for analysis of the lipid profile, inflammatory markers, leptin, and TAOC. The GKB extract produced a significant decrease in the levels of TG, LDL-c, and CRP, with a significant increase in HDL-c compared to baseline values. There were no significant changes reported in the placebo-treated group. It also produced a significant decrease in the concentrations of IL-6, TNF-α, and leptin compared to baseline values and placebo-treated groups with a significant increase in TAOC compared to baseline values. In conclusion, GKB extract, as an adjuvant with metformin, decreases inflammatory mediators, leptin level and improves the antioxidant status and lipid profile of T2DM patients improperly managed with metformin

Preliminary observation on the differential expression of metformin in preventing noise-induced hearing loss in inner ear protein group of rats / 中华劳动卫生职业病杂志

Objective: To study the protective effects of metformin on noise-induced hearing loss (NIHL) and its differential protein omics expression profile. Methods: In January 2021, 39 male Wistar rats were randomly divided into control group, noise exposure group and metformin+noise exposure group, with 13 rats in each group. Rats in the noise exposure group and metformin+noise exposure group were continuously exposed to octave noise with sound pressure level of 120 dB (A) and center frequency of 8 kHz for 4 h. Rats in the metformin+noise exposure group were treated with 200 mg/kg/d metformin 3 d before noise exposure for a total of 7 d. Auditory brainstem response (ABR) was used to test the changes of hearing thresholds before noise exposure and 1, 4, 7 d after noise exposure in the right ear of rats in each group. Tandem mass tag (TMT) quantitative proteomics was used to identify and analyze the differentially expressed protein in the inner ear of rats in each group, and it was verified by immunofluorescence staining with frozen sections. Results: The click-ABR thresholds of right ear in the noise exposure group and metformin+noise exposure group were significantly higher than those in the control group 1, 4, 7 d after noise exposure (P<0.05) . The click-ABR threshold of right ear in the metformin+noise exposure group were significantly lower than that in the noise exposure group (P<0.05) . Compared with the noise exposure group, 1035 up-regulated proteins and 1145 down-regulated proteins were differentially expressed in the metformin+noise exposure group. GO enrichment analysis showed that the significantly differentially expressed proteins were mainly involved in binding, molecular function regulation, signal transduction, and other functions. Enrichment analysis of KEGG pathway revealed that the pathways for significant enrichment of differentially expressed proteins included phosphatidylinositol 3-kinase-protein kinase B (PI3K-Akt) signaling pathway, focal adhesion, diabetic cardiomyopathy, mitogen, and mitogen-activated protein kinase (MAPK) signaling pathway. Immunofluorescence experiments showed that compared with the noise exposure group, the fluorescence intensity of insulin-like growth factor 1 receptor (IGF1R) in the metformin+noise exposure group was increased, and the fluorescence intensity of eukaryotic translation initiation factor 4E binding protein 1 (eIF4EBP1) was decreased. Conclusion: Noise exposure can lead to an increase in rat hearing threshold, and metformin can improve noise-induced hearing threshold abnormalities through multiple pathways and biological processes.

Metformin improves polycystic ovary syndrome and activates female germline stem cells in mice / 生理学报

Polycystic ovary syndrome (PCOS) is a common disease caused by complex endocrine and metabolic abnormalities in women of childbearing age. Metformin is the most widely used oral hypoglycemic drug in clinic. In recent years, metformin has been used in the treatment of PCOS, but its mechanism is not clear. In this study, we aimed to investigate the effect of metformin on PCOS and its mechanism through PCOS mouse model. Female C57BL/6J mice aged 4-5 weeks were intragastrically given letrozole (1 mg/kg daily) combined with a high-fat diet (HFD) for 21 days to establish the PCOS model. After modeling, metformin (200 mg/kg daily) was intragastrically administered. One month later, the body weight and oral glucose tolerance test (OGTT) were measured. Hematoxylin eosin (H&E) staining was used to detect the pathological changes of ovary. The serum levels of anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2 and testosterone (T) were measured by ELISA. The expression of DDX4/MVH was detected by immunohistochemistry. DDX4/MVH and PCNA were co-labeled by immunofluorescence. The protein levels of DDX4/MVH, PCNA, cyclin D2, AMPK and mTOR were detected by Western blot. The results showed that after metformin treatment, the body weights of PCOS mice were gradually returned to normal, glucose tolerance was significantly improved, serum E2 levels were increased, while AMH, LH, T levels and LH/FSH ratio were decreased. Ovarian polycystic lesions were reduced with reduced atresia follicles. Furthermore, the number of proliferative female germline stem cells (FGSCs) and levels of proliferation related proteins (PCNA, cyclin D2) were significantly increased, and the p-mTOR and p-AMPK levels were markedly up-regulated. These results suggest that metformin treatment not only improves hyperandrogenemia, glucose intolerance and polycystic ovarian lesions in PCOS, but also activates the function of FGSCs. The underlying mechanism may be related to the phosphorylation of AMPK and mTOR. These findings provide new evidence to use metformin in the treatment of PCOS and follicular development disorder.

Metformin inhibits proliferation and promotes apoptosis of HER-2 positive breast cancer cells possibly through the Hippo-YAP pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effect of metformin on the proliferation and apoptosis of HER-2-positive breast cancer cell line SKBR3 and explore the possible mechanism of its action.@*METHODS@#SKBR3 cells were treated with different concentrations (20-120 μmol/L) of metformin, and the changes in cell proliferation and colony formation ability were assessed using CCK-8 assay and crystal violet staining, respectively. Flow cytometry was performed to analyze cell apoptosis and cell cycle changes. Real-time fluorescent quantitative PCR (qRT-PCR) was used to detect mRNA expressions of YAP, TAZ, EGFR, CTGF, CYR61, E-cadherin, N-cadherin, vimentin and fibronectin in the treated cells, and the protein expressions of YAP and TAZ were detected using Western blotting; immunofluorescence assay was used to observe YAP/TAZ nuclear translocation in the cells.@*RESULTS@#Metformin treatment significantly inhibited the proliferation of SKBR3 cells (P < 0.05) in a concentration- and time-dependent manner. The results of flow cytometry showed that metformin significantly promoted apoptosis and caused cell cycle arrest at G1 phase in SKBR3 cells. Metformin treatment significantly down-regulated the mRNA expressions of YAP, TAZ, EGFR, CTGF and CYR61, N-cadherin, vimentin and fibronectin (P < 0.05) and up-regulated the expression of E-cadherin (P < 0.05); Western blotting results showed that YAP and TAZ protein expressions were significantly down-regulated in the cells after metformin treatment (P < 0.05). Immunofluorescence assay revealed that metformin treatment caused the concentration of YAP and TAZ in the cytoplasm, and significantly reduced their amount in the cell nucleus.@*CONCLUSION@#Metformin can inhibit proliferation and promote apoptosis and epithelal-mesenchymal transition of HER-2 positive breast cancer cells possibly by that inhibing YAP and TAZ expression and their nuclear localization.

Metformin and lipopolysaccharide regulate transcription of NFATc2 gene via the transcription factor RUNX2 / 南方医科大学学报

OBJECTIVE@#To construct a luciferase reporter gene vector carrying human nuclear factor of activated T cells 2 (NFATc2) gene promoter and examine the effects of metformin and lipopolysaccharide (LPS) on the transcriptional activity of NFATc2 gene.@*METHODS@#The promoter sequence of human NFATc2 gene was acquired from UCSC website for PCR amplification. NFATc2 promoter fragment was inserted into pGL3-basic plasmid double cleaved with Kpn Ⅰ and Hind Ⅲ. The resultant recombinant plasmid pGL3-NFATC2-promoter was co-transfected with the internal reference plasmid pRL-TK in 293F cells, and luciferase activity in the cells was detected. Reporter gene vectors of human NFATc2 gene promoter with different fragment lengths were also constructed and assayed for luciferase activity. The changes in transcription activity of NFATc2 gene were assessed after treatment with different concentrations of metformin and LPS for 24 h. We also examined the effect of mutation in RUNX2-binding site in NFATC2 gene promoter on the regulatory effects of metformin and LPS on NFATc2 transcription.@*RESULTS@#We successfully constructed pGL3-NFATc2-promoter plasmids carrying different lengths (2170 bp, 2077 bp, 1802 bp, 1651 bp, 1083 bp, 323 bp) of NFATc2 promoter sequences as verified by enzymatic digestion and sequencing. Transfection of 293F cells with the plasmid carrying a 1651 bp NFATc2 promoter (pGL3-1651 bp) resulted in the highest transcriptional activity of NFATc2 gene, and the luciferase activity was approximately 3.3 times that of pGL3-2170 bp (1.843 ± 0.146 vs 0.547 ± 0.085). Moderate (5 mmol/L) and high (10 mmol/L) concentrations of metformin significantly upregulated the transcriptional activity of pGL3-1651 bp by up to 2.5 and 3 folds, respectively. LPS at different doses also upregulated the transcriptional activity of pGL3-1651 bp by at least 1.6 folds. The mutation in the RUNX2 binding site on pGL3-1651 bp obviously reduced metformin- and LPS-induced enhancement of pGL3-1651bp transcription by 1.7 and 2 folds, respectively.@*CONCLUSION@#pGL3-NFATc2-promoter can be transcribed and activated in 293F cells, and LPS and metformin can activate the transcription of pGL3- NFATc2-promoter in a RUNX2-dependent manner.

Metformin alleviates intestinal epithelial barrier damage by inhibiting endoplasmic reticulum stress-induced cell apoptosis in colitis cell model / 浙江大学学报·医学版

To investigate the effect and mechanism of metformin on intestinal epithelial barrier injury in ulcerative colitis. A cell model of colitis was established by co-culture of human colon cancer cell line Caco-2 and human monocyte cell line THP-1. The colitis model cells were treated with metformin at concentration of for Flow cytometry was used to detect Caco-2 cell apoptosis, and Western blotting was used to detect the protein expression of tight junction proteins and endoplasmic reticulum stress-related proteins. After metformin treatment, the apoptosis rate of Caco-2 cells was decreased from (14.22±2.34)% to 0.61)% (=3.119, <0.05), and the expression levels of tight junction protein-1 and claudin-1 increased (=5.172 and 3.546, both <0.05). In addition, the expression levels of endoplasmic reticulum-related proteins glucose regulated protein (GRP) 78, C/EBP homologous protein (CHOP) and caspase-12, as well as the phosphorylation level of PRKR-like endoplasmic reticulum kinase (PERK) and eukaryotic translation initiation factor 2α (eIF2α) decreased (all <0.05). Metformin may alleviate the intestinal epithelial barrier damage in colitis by reducing intestinal epithelial cell apoptosis and increasing the expression of tight junction proteins, which may be associated with the inhibition of endoplasmic reticulum stress-induced apoptotic pathway.

Metformin promotes susceptibility to experimental Leishmania braziliensis infection

BACKGROUND Metformin (MET) is a hypoglycemic drug used for the treatment of diabetes, despite interference in host immunity against microorganisms. Cutaneous infection caused by pathogens such as Leishmania braziliensis (Lb), the agent responsible for cutaneous leishmaniasis (CL) in Brazil, represents an interesting model in which to evaluate the effects associated with MET. OBJECTIVE To evaluate the modulatory effect of MET in Lb infection. MATERIAL AND METHODS Experimental study of Lb infection and MET treatment in BALB/c mice and Raw 264.7 macrophages. FINDINGS MET treatment interfered with lesion kinetics, increased parasite load and reduced macrophage proliferation. Low concentrations of MET in Lb culture allow for the maintenance of stationary parasite growth phase. Lb-infected cells treated with MET exhibited increased parasite load. While both MET and Lb infection alone promoted the production of intracellular reactive oxygen species (ROS), reduced levels of ROS were seen in MET-treated Lb-infected macrophages. MAIN CONCLUSION Experimental treatment with MET interfered with the kinetics of cutaneous ulceration, increased Lb parasite load, altered ROS production and modulated cellular proliferation. Our experimental results indicate that MET interfere with the evolution of CL.

Therapeutic effects of dimethyldiguanide combined with clomifene citrate in the treatment of polycystic ovary syndrome

SUMMARY OBJECTIVE In view of the high incidence of polycystic ovary syndrome (PCOS) and the unsatisfactory therapeutic effects of dimethyldiguanide or clomifene citrate alone, our study aimed to investigate the therapeutic effects of dimethyldiguanide combined with clomifene citrate in the treatment of PCOS. METHODS A total of 79 patients with POCS and 35 healthy females were included, and endometrial biopsies were obtained. The sterol regulatory element-binding protein-1 (SREBP1) expression in endometrial tissues was detected by qRT-PCR. POC patients were randomly divided into group A (n=40) and group B (n=39). Patients in group A were treated with dimethyldiguanide combined with clomifene citrate, while patients in group B were treated with clomifene citrate alone. The number of mature follicles and cervical mucus score, follicular development rate and single follicle ovulation rate, cycle pregnancy rate, early miscarriage rate, ovulation rate, endometrial thickness, positive rate of three lines sign, follicle stimulating hormone level and luteinizing hormone level were compared between the two groups. RESULTS The expression level of SREBP1 was higher in PCOS patients than that in the healthy control. SREBP1 expression was inhibited after treatment, while the inhibitory effects of combined treatment were stronger than those of clomifene citrate alone. Compared with clomifene citrate alone, the combined treatment improved cervical mucus score, follicle development rate, single follicle ovulation rate, endometrial thickness, positive rate of three lines sign, and follicle-stimulating hormone level. CONCLUSION The therapeutic effect of combined treatment is better than clomifene citrate alone in the treatment of PCOS.

RESUMO OBJETIVO Tendo em vista a alta incidência de síndrome dos ovários policísticos (SOP) e os efeitos terapêuticos insatisfatórios da dimetildiguanida ou do citrato de clomifeno isoladamente, nosso estudo teve como objetivo investigar os efeitos terapêuticos da dimetildiguanida associada ao citrato de clomifeno no tratamento da SOP. MÉTODOS Um total de 79 pacientes com POCS e 35 mulheres saudáveis foram incluídos, e biópsias endometriais foram obtidas. A expressão da proteína de ligação do elemento regulador de esterol-1 (SREBP1) nos tecidos endometriais foi detectada por qRT-PCR. Pacientes POC foram divididos aleatoriamente em grupo A (n=40) e grupo B (n=39). Os pacientes do grupo A foram tratados com dimetildiguanida combinada com citrato de clomifeno, enquanto os pacientes do grupo B foram tratados apenas com citrato de clomifeno. O número de folículos maduros e muco cervical, taxa de desenvolvimento folicular e taxa de ovulação, taxa de gravidez, abortamento precoce, taxa de ovulação, espessura endometrial, taxa positiva de três linhas, nível de hormônio folículo estimulante e nível de hormônio luteinizante foram comparados entre os dois grupos. RESULTADOS O nível de expressão do SREBP1 foi maior nos pacientes com SOP do que no controle normal. A expressão de SREBP1 foi inibida após o tratamento, enquanto os efeitos inibidores do tratamento combinado foram mais fortes do que os do citrato de clomifeno isoladamente. Comparado com o citrato de clomifeno sozinho, o tratamento combinado melhorou significativamente a pontuação do muco cervical, a taxa de desenvolvimento folicular, a taxa de ovulação do folículo único, a espessura endometrial, a taxa positiva de três linhas de sinal e o nível de hormônio folículo estimulante. CONCLUSÃO O efeito terapêutico do tratamento combinado é melhor do que o citrato de clomifeno isolado no tratamento da SOP.

Effect of Linagliptin versus Metformin on Insulin Secretion, Insulin Sensitivity and Glucose Control in Subjects with Impaired Glucose Tolerance / Efecto de la Linagliptina Frente a la Metformina en la Secreción de Insulina, Sensibilidad a la Insulina y Control de la Glucosa en Sujetos con Intolerancia a la Glucosa

ABSTRACT Aim: The aim of the study is to evaluate the effect of linagliptin versus metformin on insulin secretion, insulin sensitivity and glucose control in patients with impaired glucose tolerance (IGT). Patients and methods: A randomized, double-blind, clinical trial with parallel groups was per-formed on 16 adults with IGT. Lipid profile and haemoglobin (HbA1c) were evaluated prior to and after the intervention. Glucose and insulin were measured at 0, 30, 60, 90 and 120 minutes after a 75-g oral dextrose load. Eight patients received metformin (500 mg) twice a day before meals for three months. The remaining eight patients received placebo (500 mg) in the morning and linagliptin (5 mg) in the evening before meals. The area under the curve (AUC) of glucose and insulin, total insulin secretion, first-phase of insulin secretion, and insulin sensitivity were assessed. Results: After linagliptin administration, a significant decrease in glucose at 90 minutes (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutes (8.8 ± 0.9 vs 6.5 ± 2.1 mmol/L, p < 0.05) and AUC of glucose (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05) were observed. Metformin administration decreased insulin significantly at 0 minutes (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusion: Three-month administration of linagliptin in patients with IGT decreased glucose at 90 and 120 minutes after a 75-g oral dextrose load and AUC of glucose. Metformin decreased insulin at 0 minutes.

RESUMEN Objetivo: El objetivo del estudio es evaluar el efecto de la linagliptina frente a la metformina en la secreción de insulina, la sensibilidad a la insulina, y el control de la glucosa en pacientes con intolerancia a la glucosa (IG). Pacientes y métodos: Se realizó un ensayo clínico aleatorio de doble ciego con grupos paralelos a 16 adultos con IG. El perfil lipídico y la hemoglobina (Hba1C) se evaluaron antes y después de la intervención. La glucosa y la insulina se midieron a los 0, 30, 60, 90 y 120 minutos después de un carga oral de 75-g dextrosa. Ocho pacientes recibieron metformina (500 mg) dos veces al día antes de las comidas por tres meses. Los ocho pacientes restantes recibieron placebo (500 mg) por la mañana y linagliptina (5 mg) por la noche antes de las comidas. El área bajo la curva (ABC) de la glucosa y la insulina, la secreción total de insulina, la primera fase de la secreción de insulina, y la sensibilidad a la insulina, fueron evaluadas. Resultados: Luego de la administración de la linagliptina, se observó una disminución significativa de la glucosa a los 90 minutos (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutos (8.8 ± 0.9 mmol/L p < 0.05) y el ABC de la glucosa (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05). La administración de metformina redujo significativamente la insulina a los 0 minutos (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusión: Tres meses de administración de linagliptina en pacientes con IG disminuyó la glucosa a los 90 y 120 minutos después de una carga oral de dextrosa de 75-g y el ABC de la glucosa. La metformina disminuyó la insulina en 0 minutos.

Effects of metformin and adiponectin on endometrial cancer cells growth / 北京大学学报(医学版)

OBJECTIVE@#To determine the effect of metformin and adiponectin on the proliferation of EC cells and the relationship between metformin and adiponectin.@*METHODS@#The proliferation impact of different concentrations of metformin and adiponectin on two types of EC cells ishikawa (IK) and HEC-1B was confirmed by CCK-8 method. qRT-PCR and Western blot were used to detect the effect of different concentrations of metformin on the changes of adiponectin receptors (AdipoR1 and AdipoR2) of the EC cells both in mRNA and protein level and the role of compound C, an adenosine monophosphate-activated protein kinase (AMPK) inhibitor, on the above effects.@*RESULTS@#(1) Both metformin and adiponectin could significantly promote the proliferation of endometrial cancer (EC) cells in a time and concentration dependent manner (P<0.05).(2)Metformin and adiponectin had synergy anti-proliferative effect on EC cells and the combination index (CI) value of IK cells was 0.906 34 and of HEC-1B cells was 0.827 65. (3)qRT-PCR was used to detect the mRNA levels of AdipoR1 and AdipoR2 after 5 mmol/L and 10 mmol/L metformin, respectively, stimulating IK and HEC-1B cells for 48 hours and the mRNA expressions of AdipoR1 and AdipoR2 were significantly increased when compared with the control group (0 mmol/L)(IK: AdipoR1 of 5 mmol/L and 10 mmol/L group: P<0.001,AdipoR2 of 5 mmol/L group: P<0.001; HEC-1B: AdipoR1 of 5 mmol/L group: P<0.001, 10 mmol/L group: P=0.023, AdipoR2 of 5 mmol/L group: P<0.001, 10 mmol/L group: P=0.024). When combined with compound C, the RNA levels of AdipoR1 and AdipoR2 were not different compared with the control group (0 mmol/L, P>0.05). (4) Western blot was used to detect the protein levels of AdipoR1 and AdipoR2 after 5 mmol/L and 10 mmol/L metformin, stimulating IK and HEC-1B cells for 48 hours and the protein level was significantly increased when compared with the control group (0 mmol/L)(IK: AdipoR1 of 5 mmol/L group: P=0.04, 10 mmol/L group: P=0.033, AdipoR2 of 5 mmol/L group: P=0.044, 10 mmol/L group: P=0.046; HEC-1B: AdipoR1 of 5 mmol/L group: P=0.04, 10 mmol/L group: P=0.049, AdipoR2 of 5 mmol/L group: P=0.043, 10 mmol/L group: P=0.035). When combined with compound C,the protein levels of AdipoR1 and AdipoR2 were not different compared with the control group (0 mmol/L, P>0.05).@*CONCLUSION@#We find that metformin and adiponectin have synergy anti-proliferative effect on EC cells. Besides, metformin can increase adiponectin receptors expressions of EC cells both in mRNA and protein levels and this effect is accomplished by the activation of AMPK signaling pathway.

Oxidative stress in patients with type 2 diabetes mellitus treated with metformin / Estresse oxidativo em pacientes com diabetes mellitus tipo 2 em tratamento com metformina

AIMS: To evaluate oxidative stress parameters in patients with type 2 diabetes mellitus treated with metformin, relating these values to its side effects, plasma levels, glycemic control, diabetic complications, lipid profile, and the influence of pharmacotherapeutic follow-up. METHODS: Patients with type 2 diabetes mellitus, on metformin and in pharmacotherapeutic follow-up for four months, were evaluated. The pharmacotherapeutic follow-up consisted in providing information and answering patients' questions about medication and disease. In addition, administration times, dosages, and presence or absence of side effects related to the use of metformin were verified. Glycemic and lipid profile, oxidative stress (superoxide dismutase and malondialdehyde) and plasma metformin were evaluated. Pearson's correlation and Spearman's correlation were performed to evaluate the relationship between the variables at the beginning of the study. The independent t-test and Mann-Whitney U test were used to assess the difference between the groups with and without diabetic complications. The range of values between the beginning and end of the study was evaluated using Student's t-test or Wilcoxon U test. The significance level was set at 5%. RESULTS: The initial sample consisted of 49 patients aged 59±9 years with a body mass index of 29.8±5.1 kg/m2 , who have had diabetes for a median time of 36 months (interquartile range of 1-240) and have been on metformin for a median time of 36 months (interquartile range of 1-180). Twenty-five patients left the study between the second and fourth meetings. Malondialdehyde levels differed between before and after pharmacotherapeutic follow-up, being positively correlated with blood glucose, glycohemoglobin, and triglyceride level, and negatively correlated with metformin and superoxide dismutase. Blood glucose, glycohemoglobin, and malondialdehyde levels increased, whereas metformin levels decreased in the group with diabetic complications, and there was a correlation between malondialdehyde and the number of diabetic complications per patient. CONCLUSIONS: In this sample of patients with type 2 diabetes mellitus treated with metformin, oxidative stress was more pronounced in those with poor glycemic control and diabetic complications.

OBJETIVOS: Avaliar parâmetros de estresse oxidativo em pacientes com diabetes mellitus tipo 2 em uso de metformina, relacionando estes valores a seus efeitos adversos, níveis plasmáticos, controle glicêmico, complicações diabéticas, perfil lipídico, e a influência do acompanhamento farmacoterapêutico. MÉTODOS: Foram avaliados pacientes com diabetes mellitus tipo 2, em uso de metformina, em acompanhamento farmacoterapêutico por quatro meses. O acompanhamento farmacoterapêutico consistiu na prestação de informações e no esclarecimento de dúvidas dos pacientes sobre a medicação e a doença. Além disto, foram verificados os horários, as doses e a presença ou não de efeitos adversos relacionados ao uso de metformina. Foram avaliados perfil glicêmico e lipídico, estresse oxidativo (superóxido dismutase e malondialdeído) e metformina plasmática. Foram realizados os testes de correlação de Pearson e de Spearman para avaliar as relações entre as variáveis no início do estudo. Para testar a diferença entre os grupos com e sem complicações diabéticas, foram utilizados o t-teste independente ou o teste U de MannWhitney. A gama de valores entre o início e o final do estudo foi avaliada utilizando o teste t de Student ou o teste de Wilcoxon U. Foi adotado um nível de significância de 5%. RESULTADOS: A amostra inicial foi composta por 49 pacientes com idade de 59±9 anos e índice de massa corporal de 29,8±5,1 kg/m2 , com diabetes por uma mediana de tempo de 36 (intervalo interquartil 1-240) meses e em uso de metformina há uma mediana de 36 (intervalo interquartil 1-180) meses. Vinte e cinco pacientes deixaram o estudo entre a segunda e a quarta reunião. Os níveis de malondialdeído diferiram entre antes e após o acompanhamento farmacoterapêutico, correlacionando-se positivamente com glicemia, glicohemoglobina e triglicerídeos e negativamente com metformina e superóxido dismutase. Encontrou-se elevação da glicemia, glicohemoglobina e malondialdeído, e diminuição da metformina no grupo com complicações diabéticas, e foi identificada correlação entre malondialdeído e o número de complicações diabéticas por paciente. CONCLUSÕES: Nesta amostra de pacientes com diabetes mellitus tipo 2 em tratamento com metformina, o estresse oxidativo foi mais pronunciado nos que apresentavam pior controle glicêmico e complicações diabéticas.

Protective effect of metformin on testicular ischemia/reperfusion injury in rats

ABSTRACT PURPOSE: To investigate the protective effect of metformin on testicular ischemia/reperfusion (I/R) injury in rats. METHODS: Eighteen adult male Wistar rats were randomly divided into three experimental groups (n=6), as follows: Sham, I/R, and Metformin. 1-hour ischemia was induced by the left testicular artery and vein clipping followed by 7 days of reperfusion. Metformin (100 mg/kg) was administrated orally for 7 days via oral gavage after ischemic period. At the end of trial, the left testis was removed for histological analysis and oxidative stress measurement. RESULTS: I/R reduced superoxide dismutase (SOD) activities and testicular Johnsen's scores accompanied by an elevation in malondialdehyde (MDA) and myeloperoxidase (MPO) levels in comparison with the sham group (P < 0.05). Compared to I/R group, metformin restored testicular Johnsen's scores, SOD activity, MDA and MPO levels (P < 0.05). CONCLUSION: Metformin has a protective effect against I/R injury on the testis.

Angiotensin II Modulates p130Cas of Podocytes by the Suppression of AMP-Activated Protein Kinase

Angiotensin II (Ang II) induces the pathological process of vascular structures, including renal glomeruli by hemodynamic and nonhemodynamic direct effects. In kidneys, Ang II plays an important role in the development of proteinuria by the modification of podocyte molecules. We have previously found that Ang II suppressed podocyte AMP-activated protein kinase (AMPK) via Ang II type 1 receptor and MAPK signaling pathway. In the present study, we investigated the roles of AMPK on the changes of p130Cas of podocyte by Ang II. We cultured mouse podocytes and treated them with various concentrations of Ang II and AMPK-modulating agents and analyzed the changes of p130Cas by confocal imaging and western blotting. In immunofluorescence study, Ang II decreased the intensity of p130Cas and changed its localization from peripheral cytoplasm into peri-nuclear areas in a concentrated pattern in podocytes. Ang II also reduced the amount of p130Cas in time and dose-sensitive manners. AMPK activators, metformin and AICAR, restored the suppressed and mal-localized p130Cas significantly, whereas, compound C, an AMPK inhibitor, further aggravated the changes of p130Cas. Losartan, an Ang II type 1 receptor antagonist, recovered the abnormal changes of p130Cas suppressed by Ang II. These results suggest that Ang II induces the relocalization and suppression of podocyte p130Cas by the suppression of AMPK via Ang II type 1 receptor, which would contribute to Ang II-induced podocyte injury.

Metformin attenuated the inflammation after renal ischemia/reperfusion and suppressed apoptosis of renal tubular epithelial cell in rats

PURPOSE:To investigate the effect of metformin on renal tubular epithelial cell apoptosis and inflammation after kidney ischemia/ reperfusion in rats.METHODS:Eighteen SD rats were randomly divided into three groups: Sham (S), Ischemia/reperfusion (I/R), and Metformin (E). Before establishing the I/R model, group E was administered metformin for three days, while groups S and I/R were administered equal volumes of saline. After three days, a right nephrectomy was performed on all groups, after which the left kidneys of groups E and I/R rats were subjected to 45 min renal ischemia. Renal function, histology, and cell apoptosis were assessed. AMPK, pAMPK, COX-2, and Caspase 3 were also detected.RESULTS:Compared to I/R group, Caspase 3 and COX-2 levels were decreased in group E. COX-2, Caspase3 and pAMPK levels were higher in groups E and I/R than in group S. The pAMPK level of group E was higher than that of I/R group, while COX-2 and caspase 3 were lower in group E than they were in the other groups. There was no significant difference between E and I/R groups in AMPK levels.CONCLUSION:Metformin preconditioning attenuated the inflammation caused by ischemia/reperfusion and inhibited the apoptosis of renal tubular epithelial cells.

Metformin induces ultrastructural alterations in hepatocytes of spontaneously hypertensive rats / La metformina induce alteraciones ultraestructurales en hepatocitos de ratas espontáneamente hipertensas

Metformin, an oral biguanide approved for the treatment of type II diabetes is widely prescribed for other clinical conditions. Currently, metformin is being investigated as potential anti-tumor agent. However, there have been recent concerns about hepatotoxicity associated with the use of metformin. This study, by means of high resolution transmission electron microscopy (TEM) and morphometry, investigated potential ultrastructural changes induced by metformin treatment on the hepatocytes of spontaneously hypertensive rats (SHR). Morphometric analysis was carried out on images of randomly selected cells from sectioned gluteraldehyde-osmium-fixed, Epon embedded liver tissue. One-way analysis of variance (ANOVA) on morphometric data showed statistically significant differences in the mean volume density (MVD) of lipid bodies (F=136.48, P<0.0001)and mean surface density (MSD) of endoplasmic reticulum (ER) (F=12.45, P<0.003) between hepatocytes of control (n=8) and metformin-treated (MT) (n=8) animals. MVD for control group was 5.42% (±0.36 SEM) but decreased significantly in the MT group (1.13%, ±0.04 SEM). Similarly, MSD of ER for control was 24.7 µm2/µm3 (±1.64 SEM) but decreased for MT animals (18.90 µm2/µm3, ±0.28 SEM). These data are most likely consistent with the effects of metformin on lipid metabolism, and may not reflect on hepatotoxicity induced by the drug, in SHRs.

La metformina, una biguanida oral aprobada para el tratamiento de la diabetes tipo II, es también ampliamente prescrita para otros cuadros clínicos. Actualmente, la metformina está siendo investigada como posible agente anti-tumoral. Sin embargo, ha habido recientes preocupaciones acerca de la hepatotoxicidad asociada con el uso de metformina. En este estudio, por medio de la microscopía electrónica de transmisión (MET) de alta resolución y morfometría, se investigaron los posibles cambios ultraestructurales, inducidos por el tratamiento con metformina, en los hepatocitos de ratas espontáneamente hipertensas (REH). El análisis morfométrico se llevó a cabo en imágenes de células seleccionadas al azar a partir de tejido hepático seccionado, fijado con glutaraldehído-osmio e inmerso en Epon. El análisis de la varianza (ANOVA) de los datos morfométricos mostró diferencias significativas en la densidad de volumen medio (DVM) de cuerpos lipídicos (F=136,48, P<0,0001) y la densidad de superficie media (DSM) del retículo endoplasmático (RE) (F=12,45, P<0,003) entre los hepatocitos control (n=8) y los animales tratados con metformina (MT) (n=8). La DVM para el grupo control fue de 5,42% (±0,36 EEM), pero disminuyó significativamente en el grupo MT (1,13%, ±0,04 EEM). Del mismo modo, la DSM del RE para el grupo control fue de 24,7 µm2/µm3 (±1,64 EEM), pero disminuyó para los animales MT (18,90 µm2/µm3, ±0,28 EEM). Estos datos están probablemente más relacionados con los efectos de la metformina sobre el metabolismo de los lípidos, y no se relacionarían con la hepatotoxicidad por inducción de la droga, en REH.

Metformin synergistically enhances antiproliferative effects of cisplatin and etoposide in NCI-H460 human lung cancer cells / Metformina sinergicamente potencializa os efeitos antiproliferativos de cisplatina e etoposideo em linhagem de celulas de cancer humano de pulmao NCI-H460

OBJECTIVE: To test the effectiveness of combining conventional antineoplastic drugs (cisplatin and etoposide) with metformin in the treatment of non-small cell lung cancer in the NCI-H460 cell line, in order to develop new therapeutic options with high efficacy and low toxicity. METHODS: We used the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and calculated the combination index for the drugs studied. RESULTS: We found that the use of metformin as monotherapy reduced the metabolic viability of the cell line studied. Combining metformin with cisplatin or etoposide produced a synergistic effect and was more effective than was the use of cisplatin or etoposide as monotherapy. CONCLUSIONS: Metformin, due to its independent effects on liver kinase B1, had antiproliferative effects on the NCI-H460 cell line. When metformin was combined with cisplatin or etoposide, the cell death rate was even higher. .

OBJETIVO: Testar a eficácia da combinação terapêutica de antineoplásicos convencionais (cisplatina e etoposídeo) com metformina em linhagem celular NCI-H460 de câncer de pulmão não pequenas células, a fim de desenvolver novas possibilidades terapêuticas com eficácia superior e reduzida toxicidade. MÉTODOS: Foi utilizado o ensaio de brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio (MTT) e calculado o índice de combinação dos fármacos estudados. RESULTADOS: Observamos que o uso de metformina em monoterapia reduziu a viabilidade celular metabólica da linhagem de células estudada. O uso de metformina em combinação com cisplatina ou etoposídeo foi sinérgico e superior à monoterapia com cisplatina ou etoposídeo. CONCLUSÕES: A metformina, devido às suas ações independentes em liver kinase B1, apresentou atividade antiproliferativa na linhagem NCI-H460 e, em combinação com cisplatina ou etoposídeo, ampliou a taxa de morte celular. .

Role of metformin in polycystic ovarian syndrome

To assess the role of Metformin in Polycystic ovarian syndrome [PCOS]. This interventional, quasi-experimental study was conducted at Department of Obstetrics and Gynaecology, Lady Reading Hospital Peshawar from October 2004 to October 2006. A total of 35 patients with PCOS were included fulfilling Rotterdam Criteria. Metformin was given in a dose of 850 mg twice a day. Patients' reassessment was done clinically on a three monthly basis while laboratory investigations and Transvaginal scan was done after two years. Data was analysed using SPSS v. 16. The mean age of the sample was 27 +/- 5.2 years. Out of 35, 29[82.8%] had primary infertility while 6[17.2%] had secondary and only 7[20%] of those conceived. Menstrual irregularities were present in30[85.7%] patients, 27[55.5%] with oligomenorrhea, 2[5.7%] with amenorrhea and 1[2.86%] with polymenorrhea. Out of these 15, 2 and 1 showed improvement, respectively. Regarding hyperandrogenism,22[62.8%] patients were with hirsutism, 3[9.4%] had acne and 10[28.5%] had hair loss. Out of these 0, 2and 3 improved, respectively. Transvaginal scan showed polycystic ovaries in all patients at baseline while the cysts dissolved in 15[42.8%] patients. Biochemical investigations like Leutinizing Hormone: Follicle Stimulating Hormone[LH:FSH], Serum Testosterone, Serum Prolactin, Random Blood Sugar[RBS] and Serum Insulin was raised in 32[91.4%], 24[68.5%], 9[25.7%], 3[8.5%] and 10[28.5%] patients respectively and 17[53.1%], 13[54.2%], 4[44.4%], 1[33.3%] and 4[40%] patients improved respectively. Metformin is an effective drug to improve the menstrual irregularities, LH:FSH and serum testosterone but it does not show improvement in clinical signs and symptoms of hyperandrogensim