Protective Effect Of Metformin Research Articles

Metformin attenuates white matter injury in neonatal mice through activating NRF2/HO-1/NF-κB pathway

White matter injury (WMI) is a major form of brain injury that occurs in preterm infants and develops into lifelong disabilities, including cerebral palsy, impaired cognitive function, and psychiatric disorders. Metformin (MET) has been reported to have neuroprotective effects. However, whether MET is responsible for neuroprotection against WMI remains unclear. In this study, we established a WMI model in neonatal mice to explore the neuroprotective effects of MET and attempted to elucidate its potential mechanisms. Our results showed that MET increased the expression of myelin basic protein (MBP), oligodendrocyte transcription factor 2 (Olig2), and CC1, improved the thickness and density of the myelin sheath, and reduced oxidative stress and microglial infiltration after chronic hypoxia induction. Moreover, MET improved memory, learning, and motor abilities as well as relieved anxiety-like behaviors in mice with WMI. These protective effects of MET may involve the upregulation of the nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1(HO-1)/NF-κB pathway related protein expressions. In addition, the NRF2 inhibitor ML385 could significantly reverse the effects of MET. In conclusion, this study suggested that MET attenuated chronic hypoxia-induced WMI through activating the NRF2/HO-1/NF-κB pathway, indicating that MET might be a promising therapeutic option for WMI.

Metformin attenuates PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway in proximal renal tubular epithelial cells

The harmful effects of PM2.5 on human health, including an increased risk of chronic kidney disease (CKD), have raised a lot of attention, but the underlying mechanisms are unclear. We used the Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) to simulate the inhalation of PM2.5 in the real environment and established an animal model by exposing C57BL/6 mice to filtered air (FA) and Particulate Matter (PM2.5) for 8 weeks. PM2.5 impaired the renal function of the mice, and the renal tubules underwent destructive changes. Analysis of NHANES data showed a correlation between reduced kidney function and higher blood levels of PM2.5 components, polychlorinated biphenyls (PCBs) and dioxins, which are Aryl hydrocarbon Receptor (AhR) ligands. PM2.5 exposure induced higher levels of AhR and CYP1A1 and oxidative stress as evidenced by the higher levels of ROS, MDA, and GSSG in kidneys of mice. PM2.5 exposure led to AhR overexpression and nuclear translocation in proximal renal tubular epithelial cells. Inhibition of AhR reduced CYP1A1 expression and PM2.5-increased levels of ROS, MDA and GSSG. Our study suggested metformin can mitigate PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway. These findings illuminated the role of AhR/CYP1A1 pathway in PM2.5-induced kidney injury and the protective effect of metformin on PM2.5-induced cellular damage, offering new insights for air pollution-related renal diseases.

Myeloid AMPK signaling restricts fibrosis but is not required for metformin improvements during CDAHFD-induced NASH in mice

Metabolic programming underpins inflammation and liver macrophage activation in the setting of chronic liver disease. Here, we sought to identify the role of an important metabolic regulator, AMP-activated protein kinase (AMPK), specifically within myeloid cells during the progression of non-alcoholic steatohepatitis (NASH) and whether treatment with metformin, a firstline therapy for diabetes and activator of AMPK could stem disease progression. Male and female Prkaa1fl/fl/Prkaa2fl/fl (Flox) control and Flox-LysM-Cre+ (MacKO) mice were fed a low-fat control or a choline-deficient, amino acid defined 45% Kcal high-fat diet (CDAHFD) for 8 weeks, where metformin was introduced in the drinking water (50 or 250 mg/kg/day) for the last 4 weeks. Hepatic steatosis and fibrosis were dramatically increased in response to CDAHFD-feeding compared to low-fat control. While myeloid AMPK signaling had no effect on markers of hepatic steatosis or circulating markers, fibrosis as measured by total liver collagen was significantly elevated in livers from MacKO mice, independent of sex. Although treatment with 50 mg/kg/day metformin had no effect on any parameter, intervention with 250 mg/kg/day metformin completely ameliorated hepatic steatosis and fibrosis in both male and female mice. While the protective effect of metformin was associated with lower final body weight, and decreased expression of lipogenic and Col1a1 transcripts, it was independent of myeloid AMPK signaling. These results suggest that endogenous AMPK signaling in myeloid cells, both liver-resident and infiltrating, acts to restrict fibrogenesis during CDAHFD-induced NASH progression but is not the mechanism by which metformin improves markers of NASH.

Metformin attenuates lung ischemia-reperfusion injury and necroptosis through AMPK pathway in type 2 diabetic recipient rats

BackgroundDiabetes mellitus (DM) can aggravate lung ischemia-reperfusion (I/R) injury and is a significant risk factor for recipient mortality after lung transplantation. Metformin protects against I/R injury in a variety of organs. However, the effect of metformin on diabetic lung I/R injury remains unclear. Therefore, this study aimed to observe the effect and mechanism of metformin on lung I/R injury following lung transplantation in type 2 diabetic rats.MethodsSprague–Dawley rats were randomly divided into the following six groups: the control + sham group (CS group), the control + I/R group (CIR group), the DM + sham group (DS group), the DM + I/R group (DIR group), the DM + I/R + metformin group (DIRM group) and the DM + I/R + metformin + Compound C group (DIRMC group). Control and diabetic rats underwent the sham operation or left lung transplantation operation. Lung function, alveolar capillary permeability, inflammatory response, oxidative stress, necroptosis and the p-AMPK/AMPK ratio were determined after 24 h of reperfusion.ResultsCompared with the CIR group, the DIR group exhibited decreased lung function, increased alveolar capillary permeability, inflammatory responses, oxidative stress and necroptosis, but decreased the p-AMPK/AMPK ratio. Metformin improved the function of lung grafts, decreased alveolar capillary permeability, inflammatory responses, oxidative stress and necroptosis, and increased the p-AMPK/AMPK ratio. In contrast, the protective effects of metformin were abrogated by Compound C.ConclusionsMetformin attenuates lung I/R injury and necroptosis through AMPK pathway in type 2 diabetic lung transplant recipient rats.

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.

Reliability of Metformin's protective effects against doxorubicin-induced cardiotoxicity: a meta-analysis of animal studies.

The protective effects of metformin (Met) against doxorubicin (Dox)-induced cardiotoxicity via potential hypotheses of mechanisms of action with unknown reliability and credibility. This study aimed to investigate the protective effects of Met against Dox-induced cardiotoxicity and the underlying mechanisms of action, as well as examine their reliability and credibility. A comprehensive search was conducted within the PubMed, Embase, Web of Science, Science Direct, Scopus, and CNKI databases from inception to 31 December 2023. Animal experiments evaluating the efficacy of Met against Dox-induced cardiotoxicity were included in this study. The primary efficacy outcomes were markers of myocardial injury. Effect size was measured using the standardized mean difference for continuous variables. Data were pooled using a random-effects model in the Stata 18 statistical software package. Twenty-one studies involving 203-208 animals treated with Dox and 271-276 animals treated with Dox and Met were included in this analysis. Quality assessment revealed high-quality scores. Pooled results favored Met treatment based on the serum lactate dehydrogenase (LDH), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTnI), and aspartate aminotransferase levels. Sensitivity analysis using the leave-one-out method demonstrated stable results. Funnel plots, Egger's test, and Begg's test confirmed potential publication bias. The oxidative stress hypothesis has been investigated extensively based on abundant evidence. Met is effective and safe for protecting against Dox-induced cardiotoxicity, thus making it an appropriate drug for clinical investigation. The oxidative stress hypothesis of mechanism of action is well established with highest reliability and credibility.

Glycoprotein Levels and Oxidative Stomach Damage in Diabetes and Prostate Cancer Model: Protective Effect of Metformin.

Men with diabetes have a higher risk of prostate cancer and people with prostate cancer are prone to stomach metastases. Therefore, researchers are continuing in order to find new approaches in the treatment of individuals with both diseases at the same time. The protective effect of metformin (which is used in the treatment of diabetes) on cancer continues to be supported by studies. The present study aimed that the protective effect of metformin in the stomach tissue of diabetic and/or prostate cancer rats was investigated through biochemical parameters. In the study, it was determined that the biochemical parameters studied showed a protective effect on stomach tissues with the administration of metformin to cancer and diabetic+cancer groups, and as a result of the principal component analysis, it was determined that the biochemical parameters studied in the stomach tissue showed a correlation.

Protective effect of metformin on pulmonary fibrosis caused by paraquat through activating AMP-activated protein kinase pathway

To observe whether metformin (MET) inhibits transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway by activating adenosine activated protein kinase (AMPK), so as to alleviate the pulmonary fibrosis caused by paraquat (PQ) poisoning in mice. Male C57BL/6J mice were randomly divided into the Control group, PQ poisoning model group (PQ group), MET intervention group (PQ+MET group), AMPK agonist group (PQ+AICAR group), and AMPK inhibitor group (PQ+MET+CC group), according to a random number table method. A mouse model of PQ poisoning was established by one-time peritoneal injection of 1 mL PQ solution (20 mg/kg). The Control group was injected with the same volume of normal saline. After 2 hours of modeling, the PQ+MET group was given 2 mL of 200 mg/kg MET solution by gavage, the PQ+AICAR group was given 2 mL of 200 mg/kg AICAR solution by intraperitoneal injection, the PQ+MET+CC group was given 2 mL of 200 mg/kg MET solution by gavage and then 1 mL complex C (CC) solution (20 mg/kg) was intraperitoneally injected, the Control group and PQ group were given 2 mL of normal saline by gavage. The intervention was given once a day for 21 consecutive days. The 21-day survival rate of ten mice in each group was calculated, and the lung tissues of remaining mice were collected at 21 days after modeling. The pathological changes of lung tissues were observed under light microscope after hematoxylin-eosin (HE) staining and Masson staining, and the degree of pulmonary fibrosis was evaluated by Ashcroft score. The content of hydroxyproline in lung tissue and oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) were detected. The protein expressions of E-cadherin, α-smooth muscle actin (α-SMA), phosphorylated AMPK (p-AMPK), TGF-β1 and phosphorylated Smad3 (p-Smad3) in lung tissue were detected by Western blotting. Compared with the Control group, the 21 days survival rate was significantly reduced, lung fibrosis and Ashcroft score were significantly increased in PQ group. In addition, the content of hydroxyproline, MDA and the protein expressions of α-SMA, TGF-β1 and p-Smad3 in lung tissue were significantly increased, while the activity of SOD and the protein expressions of E-cadherin and p-AMPK were significantly decreased in PQ group. Compared with the PQ group, the 21 days survival rates of mice were significantly improved in the PQ+MET group and PQ+AICAR group (70%, 60% vs. 20%, both P < 0.05). The degree of pulmonary fibrosis and the Ashcroft score were significantly reduced (1.50±0.55, 2.00±0.63 vs. 6.67±0.52, both P < 0.05). The content of hydroxyproline and MDA in lung tissue, as well as α-SMA, TGF-β1 and p-Smad3 protein expressions were significantly reduced [hydroxyproline (mg/L): 2.03±0.11, 3.00±0.85 vs. 4.92±0.65, MDA (kU/g): 2.06±1.48, 2.10±1.80 vs. 4.06±1.33, α-SMA/GAPDH: 0.23±0.06, 0.16±0.06 vs. 1.00±0.09, TGF-β1/GAPDH: 0.28±0.03, 0.53±0.05 vs. 0.92±0.06 p-Smad3/GAPDH: 0.52±0.04, 0.69±0.06 vs. 1.11±0.10, all P < 0.05], SOD activity and the protein expressions of E-cadherin and p-AMPK were significantly increased [SOD (μmol/g): 39.76±1.35, 33.03±1.28 vs. 20.08±1.79, E-cadherin/GAPDH: 0.91±0.08, 0.72±0.08 vs. 0.26±0.04, p-AMPK/GAPDH: 0.62±0.04, 0.60±0.01 vs. 0.20±0.04, all P < 0.05]. However, these protective effects of MET were inhibited by the addition of AMPK inhibitor CC solution. MET can effectively alleviate the degree of pulmonary fibrosis in mice poisoned with PQ, and its mechanism may be related to the activation of AMPK and inhibition of TGF-β1/Smad3 signaling pathway, which can be inhibited by AMPK inhibitor CC.

Protective effects of metformin on pancreatic β-cell ferroptosis in type 2 diabetes in vivo

Metformin (Met) is the recommended first-line therapeutic drug for type 2 diabetes mellitus (T2DM) and exerts protective effects on β-cell damage. Ferroptosis, a new form of cell death, is associated with pancreatic islet injury in patients with T2DM. However, the protective effects of Met treatment against β-cell damage through ferroptosis modulation remain under-reported. This study investigated the in vivo effects of Met treatment on pancreatic β-cell ferroptosis using two different diabetic mouse models, namely, low-dose streptozotocin (STZ) and high-fat diet (HFD)–induced diabetic mice and db/db mice. Met treatment significantly restored insulin release, reduced cell mortality, and decreased the overproduction of lipid-related reactive oxygen species in the islets of both STZ/HFD-induced diabetic mice and db/db mice. Administration of the Ras-selective lethal 3 injection significantly attenuated the antiferroptosis effects of Met. Mechanistically, Met treatment alleviated β-cell ferroptosis in T2DM, which was associated with the regulation of the GPX4/ACSL4 axis in the islets. In conclusion, our findings highlight the significance of ferroptosis in T2DM β-cell damage and provide novel insights into the protective effects of Met against islet β cells.

Oxidative brain and cerebellum injury in diabetes and prostate cancer model: Protective effect of metformin.

The body can host the spread of prostate cancer cells. Metastases from prostate cancer are more frequently seen in the brain, liver, lungs, and lymph nodes. A well-known antidiabetic drug, metformin, is also known to have antitumor effects. Our study focuses on the evaluation of potential metformin protective effects on brain and cerebellum damage in streptozotocin (STZ)-induced diabetic and Dunning prostate cancer models. In this investigation, six groups of male Copenhagen rats were created: control, diabetic (D), cancer (C), diabetic + cancer (DC), cancer + metformin, and diabetic + cancer + metformin. The brain and cerebellum tissues of the rats were taken after sacrifice. Oxidative stress markers including reduced glutathione level, lipid peroxidation, glutathione reductase, glutathione peroxidase, glutathione-S-transferase, catalase, superoxide dismutase activities, reactive oxygen species, total oxidant and total antioxidant status, lactate dehydrogenase, xanthine oxidase, acetylcholinesterase activities, protein carbonyl contents, nitric oxide and OH-proline levels, sodium potassium ATPase, carbonic anhydrase, and glucose-6-phosphate dehydrogenase activities; glycoprotein levels including hexose, hexosamine, fucose, and sialic acid levels; and histone deacetylase activity as a cancer marker were determined. Oxidative stress markers were impaired and glycoprotein levels and histone deacetylase activity were increased in the D, C, and DC groups. Metformin therapy reversed these effects. Metformin was found to protect the brain and cerebellum of STZ-induced diabetic rats with Dunning prostate cancer from harm caused by MAT-Lylu metastatic cells.

Akkermansia muciniphila, which is enriched in the gut microbiota by metformin, improves cognitive function in aged mice by reducing the proinflammatory cytokine interleukin-6

BackgroundMetformin, a type 2 diabetes treatment, improves the cognitive function of aged mice; however, whether the protective effects of metformin on cognitive function in aged mice are associated with the gut microbiome is poorly understood. Although some studies suggest that the gut microbe composition influences cognitive function and that manipulating the gut microbiota might protect against age-related cognitive dysfunction, there is no direct evidence to validate that the gut microbiota mediates the effect of metformin on cognitive improvement.ResultsIn this study, we show that the gut microbiota is altered by metformin, which is necessary for protection against ageing-associated cognitive function declines in aged mice. Mice treated with antibiotics did not exhibit metformin-mediated cognitive function protection. Moreover, treatment with Akkermansia muciniphila, which is enriched by metformin, improved cognitive function in aged mice. Mechanistically, A. muciniphila decreased pro-inflammatory-associated pathways, particularly that of the pro-inflammatory cytokine interleukin (IL)-6, in both the peripheral blood and hippocampal profiles, which was correlated with cognitive function improvement. An IL-6 antibody protected cognitive function, and an IL-6 recombinant protein abolished the protective effect of A. muciniphila on cognitive function in aged mice. ConclusionThis study reveals that A. muciniphila, which is mediated in the gut microbiota by metformin, modulates inflammation-related pathways in the host and improves cognitive function in aged mice by reducing the pro-inflammatory cytokine IL-6.D24d6SVgEDjFieya1hSRMmVideo Graphical

Protective effect of metformin on methotrexate induced reduction of rat hippocampal neural stem cells and neurogenesis

Adult neurogenesis is a process in which the adult neural stem cells produce newborn neurons that are implicated in terms of learning and memory. Methotrexate (MTX) is a chemotherapeutic drug, which has a negative effect on memory and hippocampal neurogenesis in animal models. Metformin is an antidiabetic drug with strong antioxidant capacities. We found that metformin ameliorates MTX induced deteriorations of memory and hippocampal neurogenesis in adult rats. In this study, we focus to investigate neural stem cells, biomarkers of apoptosis, and the protein for synaptogenesis, which involves in the transcription factors of the hippocampus in rats that received metformin and MTX. Male Sprague-Dawley rats were composed of control, MTX, metformin, and MTX+metformin groups. MTX (75 mg/kg, i.v.) was given on days 7 and 14, whereas metformin (200 mg/kg, i.p.) was given for 14 days. Hippocampal neural stem cells in the subgranular zone (SGZ) were quantified using immunofluorescence staining of Sox2 and nestin. Protein expression including PSD95, Casepase-3, Bax, Bcl-2, CREB, and pCREB were determined using Western blotting. MTX-treated rats displayed decreases in Sox2 and nestin-positive cells in the SGZ. Increases in Caspase-3 and Bax levels and decreases in PSD95, Bcl-2, CREB, and pCREB protein expressions in the hippocampus were also detected. However, these negative impacts of MTX were ameliorated by co-treatment with metformin. These consequences postulate that metformin has a potential to increase neural stem cells, synaptic plasticity, decreased apoptotic activities, and transcription factors, resulting in upregulation of hippocampal neurogenesis in MTX-treated rats.

The Regulation of the AMPK/mTOR Axis Mitigates Tendon Stem/Progenitor Cell Senescence and Delays Tendon Aging.

Age-related tendon disorders are closely linked with tendon stem/progenitor cell (TSPC) senescence. However, the underlying mechanisms of TSPC senescence and promising therapeutic strategies for rejuvenation of TSPC senescence remain unclear. In this study, the senescent state of TSPCs increased with age. It was also verified that the AMPK inhibition/mTOR activation is correlated with the senescent state of TSPCs. Furthermore, a low dose of metformin mitigated TSPC senescence and restored senescence-related functions, including proliferation, colony-forming ability, migration ability and tenogenic differentiation ability at the early stage of aging. The protective effects of metformin on TSPCs were regulated through the AMPK/mTOR axis. An in vivo study showed that metformin treatment postpones tendon aging and enhances AMPK phosphorylation but reduces mTOR phosphorylation in a natural aging rat model. Our study revealed new insight and mechanistic exploration of TSPC senescence and proposed a novel therapeutic treatment for age-related tendon disorders by targeting the AMPK/mTOR axis at the early stage of aging.

Protective Effect of Metformin on Venous Thrombosis in Diabetic Patients: Findings From a Systematic Review

Background: Despite the effects of metformin on cardiovascular diseases, there is limited evidence supporting its beneficial effects on venous thrombosis, and such evidence is not qualitatively synthesized both from observational and intervention studies, thereby limiting our understanding of the role of metformin in preventing venous thromboembolism (VTE). Thus, we carried out a systematic review of the epidemiological studies assessing the role of metformin in preventing VTE among diabetic patients. Methods: A systematic search of three main electronic databases including Embase, PubMed, and EBSCO was undertaken in 2021. Any study conducted between 2000 and 2021 that addressed the role of metformin in preventing venous thrombosis in patients diagnosed with type 2 diabetes mellitus was considered eligible. Results: Following a comprehensive review of the research articles based on the eligibility criteria, six articles were incorporated into the review. The findings of the review demonstrate that metformin was found to be associated with 22% to 58% risk reduction for venous thrombosis among diabetic patients. However, due to the observational studies included in the meta-analysis, the protective effect may not be independent of other risk factors or other variables. Conclusion: Overall, the findings showed a beneficial effect of metformin against venous thrombosis, meaning that metformin may play a vital role in preventing deep venous thrombosis among patients diagnosed diabetes mellitus. However, future studies are warranted before making any conclusions about the efficacy of metformin against venous thrombosis in diabetic patients. J Endocrinol Metab. 2022;12(6):161-167 doi: https://doi.org/10.14740/jem848

Metformin Use and the Risk of Myeloproliferative Neoplasms in a Danish Population Based Cohort

INTRODUCTION The peroral antidiabetic drug metformin (MT) is primarily prescribed for hyperglycaemia due to insulin-resistance in type-2 diabetes mellitus or metabolic syndrome and is a widely used drug worldwide. Use of MT has been associated with reduced cancer risk and mortality in meta-analyses (Gandini et al, 2014). Constitutive activation of the JAK-STAT pathway by the recurrent gain-of-function mutation JAK2V617F is a hallmark of MPN and has been related to the formation of bone marrow fibrosis by altering the bone marrow microenvironment. Preclinical studies of MT have shown antileukemic activity in myeloid neoplasms by activating the AMPK-mTOR-pathway, downregulating JAK2/STAT signaling, and mitochondrial activity suggesting MT as a possible treatment option in MPN (Biondani & Peyron, 2018; MacHado-Neto et al, 2018; Kawashima & Kirito, 2016). Recently, the phase II study Fibromet failed to demonstrate effect of MT in reversing bone marrow fibrosis in myelofibrosis. However, significant down regulation of the JAK-STAT-pathway and cytokine production were demonstrated (Campos et al, 2021). Currently, the association between MT use and the risk of MPNs remains to be elucidated. METHODS We conducted a nationwide population-based nested case-control study to compare MT use among patients diagnosed with MPN between 2010 and 2018 and a matched population without MPN in the Danish general population to estimate odds ratios (ORs) for MPN associated with MT use. We utilized five large nationwide Danish health registries to obtain data on exposure, outcome, and covariates for adjustment. The index date was defined as the date of MPN diagnosis and cases were identified using the National Chronic Myeloid Neoplasia Registry covering >90% of MPN cases in Denmark (Bak et al, 2016). Controls were selected by incidence density sampling (five to one) from the Danish general population matched on age, gender, and calendar year. Data on MT exposure were collected from the Danish National Prescription Registry. "Ever-use” was defined as a minimum of one prescription before the index date and "Long-term use” as >5 years of MT use (assuming an intake of the WHOs defined daily dose for MT at 2000 mg plus 25% to account for minor prescription variations and incompliances). Exposure to MT, comorbidity, and concomitant drug use were disregarded 12 months prior to the index date to avoid reverse causation. By conditional logistic regression analysis, we obtained ORs and 95% confidence intervals (95% CIs) adjusted for study design (age, gender, and index date) and fully adjusted ORs (aORs) (see footnote in Table 2 for adjusted variables). RESULTS The study population included a total of 3,816 cases and 19,080 matched controls (Table 1). Exposure assessment categorized 7.0% of cases and 8.2% of controls as "Ever-users” of MT resulting in an aOR for MPN of 0.70 (95% CI, 0.61-0.81). Long-term users were rare and comprised 1.1% of cases and 2.0% of controls resulting in an aOR for MPN 0.45 (0.33-0.63). When assessing the duration of MT exposure, we found a trend towards a dose-response relationship (<1 year: aOR 0.79 [0.62-1.00]; 1-4.99 years: 0.78 [0.64-0.95]; 5-9.99 years: 0.42 [0.29-0.61]; >10 years: 0.56 [0.30-1.03]); however, this was not statistically significant for the >10 years category, most likely due to small numbers. In stratified analyses the protective effect of long-term MT use was consistent according to gender with aOR of 0.37 (0.23-0.60) and 0.56 (0.36-0.89) for males and females, respectively, compared to males and females without MT use. In a subgroup analysis the effect was consistent across all age groups and MPN-subtypes. However, aORs did not reach statistical significance for age <60 years, myelofibrosis, and MPN unclassifiable (Table 2). CONCLUSION In this study we found an inverse association between MT use and risk of MPNs indicating a potential protective effect of MT on the development of MPNs. The protective effect was most pronounced for long-term use, older age (≥60 years) and for polycythemia vera and essential thrombocythemia. Whether this effect is causal should be determined interventional studies. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Protective Effect of Metformin Alone or in Combination with Valproic acid on Pentylenetetrazole-Induced Seizures in Mice

Abstract Objective: The aim of this study was to investigate the effects of metformin on pentylenetetrazole (PTZ)-induced seizures and the neuroprotective effect of metformin on neuronal damage after pentylenetetrazole administration. Material and Methods: Thirty-five (35) Male BALB-c Albino mice weighing 35-38 g were divided randomly into five groups: Control group (1), Saline+PTZ group (2), Valproic Acid (VPA, 200 mg/kg intraperitoneal-i.p.)+PTZ group (3), Metformin (200 mg/kg i.p.)+PTZ group (4), and VPA+Metformin+PTZ group (5). The PTZ (60 mg/kg, i.p.) was injected 30 min after drugs injection to induce seizures and seizure stages and behavioral scoring were evaluated. After completing procedure, brain tissues were removed and analyzed with biochemical and histopathological procedures. The hippocampal Cornu Ammonis (CA) 1, CA2, CA3 and DG (dentate gyrus) regions were histopathologically evaluated and oxidative stress markers (total antioxidant status (TAS), total oxidant status (TOS)) were measured. Results: Compare to Saline+PTZ group, metformin administration alone did not affect the onset time of the first myoclonic jerk (FMJ), but combination of VPA and metformin significantly increased FMJ onset time (p&amp;lt;0.05). Additionally, the treatment of metformin with or without VPA reduced the brain oxidative stress (p&amp;lt;0.05). Furthermore, histopathological assessment demonstrated that metformin administration and the combination of VPA and metformin decreased dark neuron formation in the hippocampal CA1, CA2, CA3, and DG areas (p&amp;lt;0.05). Conclusion: Metformin was found to be significantly effective in reducing epileptic seizures, brain oxidative stress, and preventing neural damage after PTZ-induced seizure

Protective effects of metformin against aluminum phosphide-induced acute hepato-renal damage in rats: An experimental approach

Phosphine (PH3), from hydrolysis of magnesium, zinc, and aluminum phosphide (AlP), is a rodenticide and insecticide which is used to avoid losses of the agriculture products. However, using of this agent may affect the human health, in a way that poisoning with AlP has a high rate of mortality and morbidities. This study determined the ameliorative effects of metformin (MET) on AlP-induced hepato- and nephro-toxicity in Wistar rats. Male rats were randomly divided into four experimental groups. Group I was the control group received coconut oil by oral gavage, group II was the model group received AlP (12 mg/kg) distributed in coconut oil by oral gavage, group III received MET (200 mg/kg; i.p.), and group IV received MET (200 mg/kg; i.p.) 30 min after intoxication. After 24 h, the serum, liver and kidney tissues were collected for histopathological and biochemical investigations. The levels of kidney function markers, blood urea nitrogen and creatinine, and liver function markers, ALP, AST and ALT, in the plasma were increased significantly followed by AlP intoxication. The results revealed that phosphine causes a significant enhancement of lipid peroxidation, while decreases the activity of superoxide dismutase in both liver and kidney tissues. Furthermore, phosphine significantly induced the up-regulation of TNF-α and phosphorylation of NF-κB in target tissues. Overall, treatment with MET abolished aforementioned alterations resulted by AlP intoxication. Furthermore, histological evaluation indicated a deleterious effect of AlP on the liver and kidney tissues along with marked increase in kidney and liver injury scores, which is mitigated by MET administration. According to our results, although metformin could not bring the changes to the level of the control group, it was indicated that this drug might possess a protective effect against AlP-induced hepato and nephrotoxicity by inhibiting inflammatory responses and oxidative stress.

Mechanisms of Metformin Improving vasodilation of coronary artery in Type 2 Diabetic Rats

In recent years, the incidence of type 2 diabetes has gradually increased. Coronary artery-related disease is one of the most common and serious complications of this. Endothelial dysfunction has become a risk factor for cardiovascular disease in patients with coronary heart disease. In this study, the protective effect of metformin on coronary artery in type 2 diabetic rats was investigated.

Mechanisms of Metformin Improving vasodilation of coronary artery in Type 2 Diabetic Rats

In recent years, the incidence of type 2 diabetes has gradually increased. Coronary artery-related disease is one of the most common and serious complications of this. Endothelial dysfunction has become a risk factor for cardiovascular disease in patients with coronary heart disease. In this study, the protective effect of metformin on coronary artery in type 2 diabetic rats was investigated.

Protective effects of metformin in various cardiovascular diseases: Clinical evidence and AMPK-dependent mechanisms.

Metformin, a well‐known AMPK agonist, has been widely used as the first‐line drug for treating type 2 diabetes. There had been a significant concern regarding the use of metformin in people with cardiovascular diseases (CVDs) due to its potential lactic acidosis side effect. Currently growing clinical and preclinical evidence indicates that metformin can lower the incidence of cardiovascular events in diabetic patients or even non‐diabetic patients beyond its hypoglycaemic effects. The underlying mechanisms of cardiovascular benefits of metformin largely involve the cellular energy sensor, AMPK, of which activation corrects endothelial dysfunction, reduces oxidative stress and improves inflammatory response. In this minireview, we summarized the clinical evidence of metformin benefits in several widely studied cardiovascular diseases, such as atherosclerosis, ischaemic/reperfusion injury and arrhythmia, both in patients with or without diabetes. Meanwhile, we highlighted the potential AMPK‐dependent mechanisms in in vitro and/or in vivo models.