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ELife Jan 2023This study aimed to investigate the protective effect of metformin on trabecular meshwork (TM) and explore its molecular mechanisms in vivo and in vitro. Ocular...
This study aimed to investigate the protective effect of metformin on trabecular meshwork (TM) and explore its molecular mechanisms in vivo and in vitro. Ocular hypertension (OHT) mouse models were induced with dexamethasone and further treated with metformin to determine the intraocular pressure (IOP)-lowering effect. Cultured human TM cells (HTMCs) were pre-stimulated with tert-butyl hydroperoxide (tBHP) to induce oxidative damage and then supplemented with metformin for another 24 hr. The expression of fibrotic markers and integrin/Rho-associated kinase (ROCK) signals, including α-smooth muscle actin (α-SMA), transforming growth factor-β (TGF-β), fibronectin, integrin beta 1, ROCK 1/2, AMP-activated protein kinase, myosin light chain 1, and F-actin were determined by western blotting and immunofluorescence. Reactive oxygen species (ROS) content was analysed using flow cytometry. Transmission electron microscopy was performed to observe microfilaments in HTMCs. It showed that metformin administration reduced the elevated IOP and alleviated the fibrotic activity of aqueous humour outflow in OHT models. Additionally, metformin rearranged the disordered cytoskeleton in the TM both in vivo and in vitro and significantly inhibited ROS production and activated integrin/ROCK signalling induced by tBHP in HTMCs. These results indicated that metformin reduced the elevated IOP in steroid-induced OHT mouse models and exerted its protective effects against oxidative injury by regulating cytoskeleton remodelling through the integrin/ROCK pathway. This study provides new insights into metformin use and preclinical evidence for the potential treatment of primary open-angle glaucoma.
Topics: Mice; Animals; Humans; Trabecular Meshwork; Glaucoma, Open-Angle; Metformin; Reactive Oxygen Species; Integrins; Glaucoma; Ocular Hypertension; Cells, Cultured; Oxidative Stress
PubMed: 36598818
DOI: 10.7554/eLife.81198 -
EMBO Molecular Medicine Dec 2022Metformin, a well-known antidiabetic drug, has been repurposed for cancer treatment; however, recently observed drug resistance and tumor metastasis have questioned its...
Metformin, a well-known antidiabetic drug, has been repurposed for cancer treatment; however, recently observed drug resistance and tumor metastasis have questioned its further application. Here, we found that long-term metformin exposure led to metabolic adaptation of hepatocellular carcinoma (HCC) cells, which was characterized by an obvious epithelial-mesenchymal transition (EMT) phenotype and compensatory elevation of oxidative phosphorylation (OXPHOS). TOMM34, a translocase of the outer mitochondrial membrane, was upregulated to promote tumor metastasis in response to metformin-induced metabolic stress. Mechanistically, TOMM34 interacted with ATP5B to preserve F F -ATPase activity, which conferred mitochondrial OXPHOS and ATP production. This metabolic preference for OXPHOS suggested a large requirement of energy supply by cancer cells to survive and spread in response to therapeutic stress. Notably, disturbing the interaction between TOMM34 and ATP5B using Gboxin, a specific OXPHOS inhibitor, increased sensitivity to metformin and suppressed tumor progression both in vitro and in vivo. Overall, this study demonstrates a molecular link of the TOMM34/ATP5B-ATP synthesis axis during metformin adaptation and provides promising therapeutic targets for metformin sensitization in cancer treatment.
Topics: Humans; Metformin; Carcinoma, Hepatocellular; Liver Neoplasms; Cell Line; Adenosine Triphosphate; Mitochondrial Precursor Protein Import Complex Proteins
PubMed: 36321555
DOI: 10.15252/emmm.202216082 -
Pharmacological Research Mar 2022Metformin is the oldest and most commonly used first-line antidiabetic drug because of its good clinical efficacy, high safety, low cost and easy access. At the same... (Review)
Review
Metformin is the oldest and most commonly used first-line antidiabetic drug because of its good clinical efficacy, high safety, low cost and easy access. At the same time, in recent years, we have found that its role as a therapeutic drug is gradually expanding. A large number of basic studies have shown that metformin may become a promising attractive candidate for drug repurposing. Therefore, it is extremely beneficial to conduct an in-depth discussion on the main mechanism of metformin. As early as the year 1950, studies showed that metformin played a biological role by regulating mitochondria. Then, ground-breaking studies showed that metformin functions by inhibiting complex I in the mitochondrial respiratory chain. Although there are still many controversies about the key molecular targets of metformin, with the emergence of more and more evidence, it gradually came to be concluded that mitochondria play a central role in the application of metformin. Mitochondria are important fulcrums for cell functions. The exact mechanism of action in mitochondria of this pleiotropic anti-hyperglycaemic molecule is still unclear. This review article explores the core role of mitochondria in the pharmacological and toxicological effects of metformin, and summarises the mechanism of action if metformin in mitochondria. It also provides ideas and supporting evidence for the re-development and reuse of metformin as an old drug, as well as new insight into the treatment of human diseases.
Topics: Humans; Hypoglycemic Agents; Metformin; Mitochondria
PubMed: 35124206
DOI: 10.1016/j.phrs.2022.106114 -
Science Advances Sep 2022Ovarian fibrosis is a pathological condition associated with aging and is responsible for a variety of ovarian dysfunctions. Given the known contributions of tissue...
Ovarian fibrosis is a pathological condition associated with aging and is responsible for a variety of ovarian dysfunctions. Given the known contributions of tissue fibrosis to tumorigenesis, it is anticipated that ovarian fibrosis may contribute to ovarian cancer risk. We recently reported that diabetic postmenopausal women using metformin had ovarian collagen abundance and organization that were similar to premenopausal ovaries from nondiabetic women. In this study, we investigated the effects of aging and metformin on mouse ovarian fibrosis at a single-cell level. We discovered that metformin treatment prevented age-associated ovarian fibrosis by modulating the proportion of fibroblasts, myofibroblasts, and immune cells. Senescence-associated secretory phenotype (SASP)-producing fibroblasts increased in aged ovaries, and a unique metformin-responsive subpopulation of macrophages emerged in aged mice treated with metformin. The results demonstrate that metformin can modulate specific populations of immune cells and fibroblasts to prevent age-associated ovarian fibrosis and offers a new strategy to prevent ovarian fibrosis.
Topics: Animals; Female; Fibroblasts; Fibrosis; Humans; Metformin; Mice; Myofibroblasts; Ovary
PubMed: 36054356
DOI: 10.1126/sciadv.abq1475 -
Journal For Immunotherapy of Cancer May 2023Despite their revolutionary success in cancer treatment over the last decades, immunotherapies encounter limitations in certain tumor types and patients. The efficacy of...
BACKGROUND
Despite their revolutionary success in cancer treatment over the last decades, immunotherapies encounter limitations in certain tumor types and patients. The efficacy of immunotherapies depends on tumor antigen-specific CD8 T-cell viability and functionality within the immunosuppressive tumor microenvironment, where oxygen levels are often low. Hypoxia can reduce CD8 T-cell fitness in several ways and CD8 T cells are mostly excluded from hypoxic tumor regions. Given the challenges to achieve durable reduction of hypoxia in the clinic, ameliorating CD8 T-cell survival and effector function in hypoxic condition could improve tumor response to immunotherapies.
METHODS
Activated CD8 T cells were exposed to hypoxia and metformin and analyzed by fluorescence-activated cell sorting for cell proliferation, apoptosis and phenotype. In vivo, metformin was administered to mice bearing hypoxic tumors and receiving either adoptive cell therapy with tumor-specific CD8 T cells, or immune checkpoint inhibitors; tumor growth was followed over time and CD8 T-cell infiltration, survival and localization in normoxic or hypoxic tumor regions were assessed by flow cytometry and immunofluorescence. Tumor oxygenation and hypoxia were measured by electron paramagnetic resonance and pimonidazole staining, respectively.
RESULTS
We found that the antidiabetic drug metformin directly improved CD8 T-cell fitness in hypoxia, both in vitro and in vivo. Metformin rescued murine and human CD8 T cells from hypoxia-induced apoptosis and increased their proliferation and cytokine production, while blunting the upregulation of programmed cell death protein 1 and lymphocyte-activation gene 3. This appeared to result from a reduced production of reactive oxygen species, due to the inhibition of mitochondrial complex I. Differently from what others reported, metformin did not reduce tumor hypoxia, but rather increased CD8 T-cell infiltration and survival in hypoxic tumor areas, and synergized with cyclophosphamide to enhance tumor response to adoptive cell therapy or immune checkpoint blockade in different tumor models.
CONCLUSIONS
This study describes a novel mechanism of action of metformin and presents a promising strategy to achieve immune rejection in hypoxic and immunosuppressive tumors, which would otherwise be resistant to immunotherapy.
Topics: Humans; Animals; Mice; Metformin; Neoplasms; CD8-Positive T-Lymphocytes; Immunotherapy; Immunosuppression Therapy; Immunosuppressive Agents; Hypoxia; Tumor Microenvironment
PubMed: 37147018
DOI: 10.1136/jitc-2022-005719 -
Diabetes Research and Clinical Practice Sep 2018Metformin is a lipophilic biguanide which inhibits hepatic gluconeogenesis and improves peripheral utilization of glucose. It is the first line pharmacotherapy for... (Review)
Review
Metformin is a lipophilic biguanide which inhibits hepatic gluconeogenesis and improves peripheral utilization of glucose. It is the first line pharmacotherapy for glucose control in patients with Type 2 diabetes due to its safety, efficacy and tolerability. Metformin exhibits pleotropic effects, which may have beneficial effects on a variety of tissues independent of glucose control. A potential anti-tumourigenic effect of metformin may be mediated by its role in activating AMP-kinase, which in turn inhibits mammalian target of rapamycin (mTOR). Non-AMPK dependent protective pathways may include reduction of insulin, insulin-like growth factor-1, leptin, inflammatory pathways and potentiation of adiponectin, all of which may have a role in tumourigenesis. A role in inhibiting cancer stem cells is also postulated. A number of large scale observational and cohort studies suggest metformin is associated with a reduced risk of a number of cancers, although the data is not conclusive. Recent randomised studies reporting use of metformin in treatment of cancer have revealed mixed results, and the results of much larger randomised trials of metformin as an adjuvant therapy in breast and colorectal cancers are awaited.
Topics: Animals; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Metformin; Neoplasms
PubMed: 29807101
DOI: 10.1016/j.diabres.2018.05.023 -
EBioMedicine Oct 2023Metformin shows beneficial effects on cardiometabolic health in diabetic individuals. However, the beneficial effects in the general population, especially in...
BACKGROUND
Metformin shows beneficial effects on cardiometabolic health in diabetic individuals. However, the beneficial effects in the general population, especially in non-diabetic individuals are unclear. We aim to estimate the effects of perturbation of seven metformin targets on cardiometabolic health using Mendelian randomization (MR).
METHODS
Genetic variants close to metformin-targeted genes associated with expression of the corresponding genes and glycated haemoglobin (HbA) level were used to proxy therapeutic effects of seven metformin-related drug targets. Eight cardiometabolic phenotypes under metformin trials were selected as outcomes (average N = 466,947). MR estimates representing the weighted average effects of the seven effects of metformin targets on the eight outcomes were generated. One-sample MR was applied to estimate the averaged and target-specific effects in 338,425 non-diabetic individuals in UK Biobank.
FINDINGS
Genetically proxied averaged effects of five metformin targets, equivalent to a 0.62% reduction of HbA level, was associated with 37.8% lower risk of coronary artery disease (CAD) (odds ratio [OR] = 0.62, 95% confidence interval [CI] = 0.46-0.84), lower levels of body mass index (BMI) (β = -0.22, 95% CI = -0.35 to -0.09), systolic blood pressure (SBP) (β = -0.19, 95% CI = -0.28 to -0.09) and diastolic blood pressure (DBP) levels (β = -0.29, 95% CI = -0.39 to -0.19). One-sample MR suggested that the seven metformin targets showed averaged and target-specific beneficial effects on BMI, SBP and DBP in non-diabetic individuals.
INTERPRETATION
This study showed that perturbation of seven metformin targets has beneficial effects on BMI and blood pressure in non-diabetic individuals. Clinical trials are needed to investigate whether similar effects can be achieved with metformin medications.
FUNDING
Funding information is provided in the Acknowledgements.
Topics: Humans; Metformin; Mendelian Randomization Analysis; Risk; Coronary Artery Disease; Genome-Wide Association Study; Diabetes Mellitus; Polymorphism, Single Nucleotide
PubMed: 37734206
DOI: 10.1016/j.ebiom.2023.104803 -
Aging Cell Nov 2023Muscle inflammation and fibrosis underlie disuse-related complications and may contribute to impaired muscle recovery in aging. Cellular senescence is an emerging link... (Randomized Controlled Trial)
Randomized Controlled Trial
Disuse-induced muscle fibrosis, cellular senescence, and senescence-associated secretory phenotype in older adults are alleviated during re-ambulation with metformin pre-treatment.
Muscle inflammation and fibrosis underlie disuse-related complications and may contribute to impaired muscle recovery in aging. Cellular senescence is an emerging link between inflammation, extracellular matrix (ECM) remodeling and poor muscle recovery after disuse. In rodents, metformin has been shown to prevent cellular senescence/senescent associated secretory phenotype (SASP), inflammation, and fibrosis making it a potentially practical therapeutic solution. Thus, the purpose of this study was to determine in older adults if metformin monotherapy during bed rest could reduce muscle fibrosis and cellular senescence/SASP during the re-ambulation period. A two-arm controlled trial was utilized in healthy male and female older adults (n = 20; BMI: <30, age: 60 years+) randomized into either placebo or metformin treatment during a two-week run-in and 5 days of bedrest followed by metformin withdrawal during 7 days of recovery. We found that metformin-treated individuals had less type-I myofiber atrophy during disuse, reduced pro-inflammatory transcriptional profiles, and lower muscle collagen deposition during recovery. Collagen content and myofiber size corresponded to reduced whole muscle cellular senescence and SASP markers. Moreover, metformin treatment reduced primary muscle resident fibro-adipogenic progenitors (FAPs) senescent markers and promoted a shift in fibroblast fate to be less myofibroblast-like. Together, these results suggest that metformin pre-treatment improved ECM remodeling after disuse in older adults by possibly altering cellular senescence and SASP in skeletal muscle and in FAPs.
Topics: Male; Female; Humans; Metformin; Senescence-Associated Secretory Phenotype; Cellular Senescence; Muscle, Skeletal; Inflammation; Walking; Collagen; Fibrosis
PubMed: 37486024
DOI: 10.1111/acel.13936 -
Molecular Biology Reports Jan 2023Metformin has good anti-hyperglycemic effectiveness, but does not induce hypoglycemia,is very safe, and has become the preferred drug for the treatment of type 2... (Review)
Review
BACKGROUND
Metformin has good anti-hyperglycemic effectiveness, but does not induce hypoglycemia,is very safe, and has become the preferred drug for the treatment of type 2 diabetes. Recently, the other effects of metformin, such as being anti-inflammatory and delaying aging, have also attracted increased attention.
METHODS AND RESULTS
The relevant literatures on pubmed and other websites for reading, classification and sorting, and did not involve any animal experiments.
CONCLUSION
Metformin has anti-inflammatory effects through multiple routes, which provides potential therapeutic targets for certain inflammatory diseases, such as neuroinflammation and rheumatoid arthritis. In addition, inflammation is a key component of tumor occurrence and development ; thus, targeted inflammatory intervention is a significant benefit for both cancer prevention and treatment. Therefore, metformin may have further potential for inflammation-related disease prevention and treatmen. However, the inflammatory mechanism is complex; various molecules are connected and influence each other. For example, metformin significantly inhibits p65 nuclear translocation, but pretreatment with compound C, an AMPK inhibitor, abolishes this effect, and silencing of HMGB1 inhibits NF-κB activation . SIRT1 deacetylates FoxO, increasing its transcriptional activity . mTOR in dendritic cells regulates FoxO1 via AKT. The interactions among various molecules should be further explored to clarify their specific mechanisms and provide more direction for the treatment of inflammatory diseases, as well as cancer.
Topics: Animals; Metformin; Diabetes Mellitus, Type 2; NF-kappa B; Inflammation; Anti-Inflammatory Agents; Neoplasms; AMP-Activated Protein Kinases
PubMed: 36319785
DOI: 10.1007/s11033-022-07954-5 -
JAMA Network Open Feb 2021Combining 2 first-line treatments for erectile dysfunction (ED) or initiating other modalities in addition to a first-line therapy may produce beneficial outcomes. (Meta-Analysis)
Meta-Analysis
IMPORTANCE
Combining 2 first-line treatments for erectile dysfunction (ED) or initiating other modalities in addition to a first-line therapy may produce beneficial outcomes.
OBJECTIVE
To assess whether different ED combination therapies were associated with improved outcomes compared with first-line ED monotherapy in various subgroups of patients with ED.
DATA SOURCES
Studies were identified through a systematic search in MEDLINE, Cochrane Library, and Scopus from inception of these databases to October 10, 2020.
STUDY SELECTION
Randomized clinical trials or prospective interventional studies of the outcomes of combination therapy vs recommended monotherapy in men with ED were identified. Only comparative human studies, which evaluated the change from baseline of self-reported erectile function using validated questionnaires, that were published in any language were included.
DATA EXTRACTION AND SYNTHESIS
Data extraction and synthesis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.
MAIN OUTCOMES AND MEASURES
A meta-analysis was conducted that included randomized clinical trials that compared outcomes of combination therapy with phosphodiesterase type 5 (PDE5) inhibitors plus another agent vs PDE5 inhibitor monotherapy. Separate analyses were performed for the mean International Index of Erectile Function (IIEF) score change from baseline and the number of adverse events (AEs) by different treatment modalities and subgroups of patients.
RESULTS
A total of 44 studies included 3853 men with a mean (SD) age of 55.8 (11.9) years. Combination therapy compared with monotherapy was associated with a mean IIEF score improvement of 1.76 points (95% CI, 1.27-2.24; I2 = 77%; 95% PI, -0.56 to 4.08). Adding daily tadalafil, low-intensity shockwave therapy, vacuum erectile device, folic acid, metformin hydrochloride, or angiotensin-converting enzyme inhibitors was associated with a significant IIEF score improvement, but each measure was based on only 1 study. Specifically, the weighted mean difference (WMD) in IIEF score was 1.70 (95% CI, 0.79-2.61) for the addition of daily tadalafil, 3.50 (95% CI, 0.22-6.78) for the addition of low-intensity shockwave therapy, 8.40 (95% CI, 4.90-11.90) for the addition of a vacuum erectile device, 3.46 (95% CI, 2.16-4.76) for the addition of folic acid, 4.90 (95% CI, 2.82-6.98) for the addition of metformin hydrochloride and 2.07 (95% CI, 1.37-2.77) for the addition of angiotensin-converting enzyme inhibitors. The addition of α-blockers to PDE5 inhibitors was not associated with improvement in IIEF score (WMD, 0.80; 95% CI, -0.06 to 1.65; I2 = 72%). Compared with monotherapy, combination therapy was associated with improved IIEF score in patients with hypogonadism (WMD, 1.61; 95% CI, 0.99-2.23; I2 = 0%), monotherapy-resistant ED (WMD, 4.38; 95% CI, 2.37-6.40; I2 = 52%), or prostatectomy-induced ED (WMD, 5.47; 95% CI, 3.11-7.83; I2 = 53%). The treatment-related AEs did not differ between combination therapy and monotherapy (odds ratio, 1.10; 95% CI, 0.66-1.85; I2 = 78%). Despite multiple subgroup and sensitivity analyses, the levels of heterogeneity remained high.
CONCLUSIONS AND RELEVANCE
This study found that combination therapy of PDE5 inhibitors and antioxidants was associated with improved ED without increasing the AEs. Treatment with PDE5 inhibitors and daily tadalafil, shockwaves, or a vacuum device was associated with additional improvement, but this result was based on limited data. These findings suggest that combination therapy is safe, associated with improved outcomes, and should be considered as a first-line therapy for refractory, complex, or difficult-to-treat cases of ED.
Topics: Adrenergic alpha-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antioxidants; Combined Modality Therapy; Drug Therapy, Combination; Equipment and Supplies; Erectile Dysfunction; Extracorporeal Shockwave Therapy; Folic Acid; Humans; Hypoglycemic Agents; Male; Metformin; Phosphodiesterase 5 Inhibitors; Sildenafil Citrate; Tadalafil; Treatment Outcome; Vitamin B Complex
PubMed: 33599772
DOI: 10.1001/jamanetworkopen.2020.36337