Metformin enhances epithelial cell growth inhibition via the protein kinase-insulin-like growth factor binding protein-1 pathway

BACKGROUND

Abnormal stromal-epithelial cell communication is a pathogenic mechanism in endometriosis, and metformin can modulate it. Insulin-like growth factor binding protein-1 (IGFBP1) plays a role in endometriosis, but the exact mechanism is unknown. IGFBP1 is reportedly a downstream target of metformin in some diseases. We aimed to investigate the role of IGFBP1 in endometriosis development, whether it is associated with abnormal communication, and whether metformin affects IGFBP1 expression.

METHODS

Patients who underwent surgical treatment for endometriosis or other diseases were enrolled. Ten patients with ovarian-type endometriosis and eight patients each who underwent surgical treatment for other lesions with or without endometriosis were selected, and their tissues taken for cell proliferation, western blotting, polymerase chain reaction, and knockdown experiments.

RESULTS

Ectopic and eutopic stromal cells (EcSCs and EuSCs) lost their ability to inhibit epithelial cell proliferation, and IGFBP1 expression was downregulated in both groups of stromal cells compared to that in normal stromal cells (NSCs; 1.09 vs. 0.25, p = .0002 1.09 vs. 0.57, p = .0029). In an EcSC IGFBP1 overexpression model, the ability of EcSCs to inhibit epithelial cell proliferation was enhanced (EdU positivity decreased from 38% to 25%, p = .0001). Furthermore, adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation was downregulated in EcSCs and EuSCs compared to that in NSCs (0.99 vs. 0.42, p = .0006/0.99 vs. 0.57, p = 0.0032). Treatment of EcSCs with metformin increased AMPK phosphorylation (0.47 vs. 1.04, p = .0107) while upregulating IGFBP1 expression (0.69 vs. 1.01, p = .0164), whereas pre-treatment with an AMPK phosphorylation inhibitor abrogated metformin-induced IGFBP1 upregulation.

CONCLUSIONS

IGFBP1 mediates aberrant stromal-epithelial communication in endometriosis. Metformin can upregulate IGFBP1 expression in EcSCs by activating AMPK, and upregulated IGFBP1 enhances the inhibition of epithelial cell proliferation. IGFBP1 is expected to be a therapeutic target for endometriosis.

Comparative effects of the antioxidant glutathione with metformin and Diane-35 on hormonal, metabolic, and inflammatory indicators in a DHEA-induced PCOS rat model

OBJECTIVE

Comparison of hormonal, metabolic and inflammatory markers of glutathione with metformin and Diane-35 in a rat model of PCOS induced by dehydroepiandrosterone.

METHODS

Twenty-five female rats were randomized into four groups. Group 1 was administered a subcutaneous dose of 0.2 ml saline/day. Group 2 was given 0.2 ml of 1% carboxymethyl cellulose (CMC)/day orally for 28 days. A PCOS model was established with DHEA in rats. Group 3 was given 4.5 mg/kg/day of Diane-35 orally dissolved in 1% CMC for 28 days. Group 4 was given 300 mg/kg/day of metformin orally dissolved in 1 ml of saline for 28 days, and Group 5 was administered 100 mg/kg of glutathione intraperitoneally on days 35, 42, and 49. On day 56, the rats were sacrificed. Serum markers and follicle count were examined.

RESULTS

Serum IL-6, hs-CRP, insulin, testosterone, SHBG, and MDA values were significantly lower in the glutathione group than in the PCOS group (p = 0.0006, p = 0.023, p = 0.0082, p = 0.0007, p = 0.0048, and p < 0.0001, respectively).The number of all follicles was similar between the control and glutathione groups (p < 0.05). When we compared the other groups with the PCOS group, the number of primary, secondary, atretic, and cystic follicles was significantly lower in the metformin and glutathione groups. The number of primordial and antral follicles was significantly higher than in the PCOS group.

CONCLUSIONS

Glutathione plays anti-inflammatory and antioxidant roles, similar to metformin, by lowering serum IL-6, insulin, testosterone, CRP, and MDA levels; decreasing atretic/cystic follicle count; and improving antral follicle count and folliculogenesis in PCOS patients.

Metformin ameliorates endometrial thickness in a rat model of thin endometrium

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

Metformin treatment of juvenile mice alters aging-related developmental and metabolic phenotypes in sex-dependent and sex-independent manners

Metformin has attracted increasing interest for its potential benefits in extending healthspan and longevity. This study examined the effects of early-life metformin treatment on the development and metabolism of C57BL/6 J (B6) mice, with metformin administered to juvenile mice from 15 to 56 days of age. Metformin treatment led to decreased body weight in both sexes (P < 0.05, t-test). At 9 weeks of age, mice were euthanized and organ weights were recorded. The relative weight of retroperitoneal fat was decreased in females, while relative weights of perigonadal and retroperitoneal fat were decreased, and relative liver weight was increased in males (P < 0.05, t-test). Glucose and insulin tolerance tests (GTT and ITT) were conducted at the age of 7 weeks. ANOVA revealed a significant impairment in insulin sensitivity by the treatment, and a significantly interactive effect on glucose tolerance between sex and treatment, underscoring a disparity in GTT between sexes in response to the treatment. Metformin treatment reduced circulating insulin levels in fasting and non-fasting conditions for male mice, with no significant alterations observed in female mice. qRT-PCR analysis of glucose metabolism-related genes (Akt2, Glut2, Glut4, Irs1, Nrip1, Pi3k, Pi3kca, Pkca) in the liver and skeletal muscle reveals metformin-induced sex- and organ-specific effects on gene expression. Comparison with previous studies in heterogeneous UM-HET3 mice receiving the same treatment suggests that genetic differences may contribute to variability in the effects of metformin treatment on development and metabolism. These findings indicate that early-life metformin treatment affects development and metabolism in both sex- and genetics-dependent manners.

AMPK-mediated autophagy pathway activation promotes ΔFosB degradation to improve levodopa-induced dyskinesia

BACKGROUND

Parkinson's disease patients on chronic levodopa often suffer from motor complications, which tend to reduce their quality of life. Levodopa-induced dyskinesia (LID) is one of the most prevalent motor complications, often characterized by abnormal involuntary movements, and the pathogenesis of LID is still unclear but recent studies have suggested the involvement of autophagy.

METHODS

The onset of LID was mimicked by chronic levodopa treatment in a unilateral 6-hydroxydopamine (6-OHDA) -lesion rat model. Overexpression of ΔFosB in HEK293 cells to mimic the state of ΔFosB accumulation. The modulation of the AMP-activated protein kinase (AMPK)-mediated autophagy pathway using by metformin, AICAR (an AMPK activator), Compound C (an AMPK inhibitor) and chloroquine (an autophagy pathway inhibitor). The severity of LID was assessed by axial, limb, and orofacial (ALO) abnormal involuntary movements (AIMs) score and in vivo electrophysiology. The activity of AMPK pathway as well as autophagy markers and FosB-ΔFosB levels were detected by western blotting. RT-qPCR was performed to detect the transcription level of FosB-ΔFosB. The mechanism of autophagy dysfunction was further explored by immunofluorescence and transmission electron microscopy.

RESULTS

In vivo experiments demonstrated that chronic levodopa treatment reduced AMPK phosphorylation, impaired autophagosome-lysosomal fusion and caused FosB-ΔFosB accumulation in the striatum of PD rats. Long-term metformin intervention improved ALO AIMs scores as well as reduced the mean power of high gamma (hγ) oscillations and the proportion of striatal projection neurons unstable in response to dopamine for LID rats. Moreover, the intervention of metformin promoted AMPK phosphorylation, ameliorated the impairment of autophagosome-lysosomal fusion, thus, promoting FosB-ΔFosB degradation to attenuate its accumulation in the striatum of LID rats. However, the aforementioned roles of metformin were reversed by Compound C and chloroquine. The results of in vitro studies demonstrated the ability of metformin and AICAR to attenuate ΔFosB levels by promoting its degradation, while Compound C and chloroquine could block this effect.

CONCLUSIONS

In conclusion, our results suggest that long-term metformin treatment could promote ΔFosB degradation and thus attenuate the development of LID through activating the AMPK-mediated autophagy pathway. Overall, our results support the AMPK-mediated autophagy pathway as a novel therapeutic target for LID and also indicate that metformin is a promising therapeutic candidate for LID.

Revealing metabolic and biochemical variations via 1H NMR metabolomics in streptozotocin-nicotinamide-induced diabetic rats treated with metformin

The increasing prevalence of lean diabetes has prompted the generation of animal models that mimic metabolic disease in humans. This study aimed to determine the optimum streptozotocin-nicotinamide (STZ-NA) dosage ratio to elicit lean diabetic features in a rat model. It also used a proton nuclear magnetic resonance (1H NMR) urinary metabolomics approach to identify the metabolic effect of metformin treatment on this novel rat model. Three different STZ-NA dosage regimens (by body weight: Group A: 110 mg/kg NA and 45 mg/kg STZ; Group B: 180 mg/kg NA and 65 mg/kg STZ and Group C: 120 mg/kg NA and 60 mg/kg STZ) were administered to Sprague-Dawley rats along with oral metformin. Group A diabetic rats (A-DC) showed favorable serum biochemical analyses and a more positive response toward oral metformin administration relative to the other STZ-NA dosage ratio groups. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed that glucose, citrate, pyruvate, hippurate, and methylnicotinamide differentiating the OPLS-DA of A-MTF rats (Group A diabetic rats treated with metformin) and A-DC model rats. Subsequent metabolic pathway analyses revealed that metformin treatment was associated with improvement in dysfunctions caused by STZ-NA induction, including carbohydrate metabolism, cofactor metabolism, and vitamin and amino acid metabolism. In conclusion, our results identify the best STZ-NA dosage ratio for a rat model to exhibit lean type 2 diabetic features with optimum sensitivity to metformin treatment. The data presented here could be informative to improve our understanding of non-obese diabetes in humans through the identification of possible activated metabolic pathways in the STZ-NA-induced diabetic rats model.

Metformin modulates autophagic pathway in renal fibrosis induced by carbon tetrachloride in adult male albino rats

BACKGROUNDS

Chronic kidney disease (CKD) is a global public health problem. All progressive chronic kidney disease (CKD) is characterized by tubulointerstitial fibrosis. Exposure to high concentrations of carbon tetrachloride (including vapor) can destroy the kidneys. Autophagy played an important role in maintaining the homeostasis of organs. Impaired autophagy was frequently associated with renal damage and fibrosis. Recent data suggests that metformin protects against a variety of kidney disorders.

AIM

To investigate the protective role of metformin on carbon tetrachloride induced renal damage via autophagy pathway.

MATERIALS AND METHODS

Forty adult male albino rats were divided into four equal groups (10 rats, each); Group 1: control group. Group 2: olive oil group received olive oil 1.5 mg/kg twice weekly S.C for 12 weeks. Group 3: The ccl4 group, the rats were received ccl4 1.5 mg/kg twice weekly S.C for 12 weeks. Group 4: CCL4 and Metformin group received concomitant treatment of CCL4, 1.5 mg/kg twice weekly S.C and 100 mg/kg/day Metformin orally for 12 weeks. After sacrifice, kidneys were taken from all animal groups and processed for light and electron microscopy, immunological studies and biochemical tests. Statistical analysis was done.

RESULTS

Administration of ccl4 resulted in histopathological changes in the kidney tissue in the form of areas of tissue destruction, inflammatory cell infiltration, congestion and fibrosis. Ultrastructurally, irregular thickening of GBM was observed. Improvement was noticed with concomitant treatment of ccl4 with metformin.

CONCLUSION

Metformin administration can modulate histological and biochemical effects in the renal tissue induced by of ccl4.

ACAD10 is not required for metformin's metabolic actions or for maintenance of whole-body metabolism in C57BL/6J mice

AIM

Acyl-coenzyme A dehydrogenase family member 10 (ACAD10) is a mitochondrial protein purported to be involved in the fatty acid oxidation pathway. Metformin is the most prescribed therapy for type 2 diabetes; however, its precise mechanisms of action(s) are still being uncovered. Upregulation of ACAD10 is a requirement for metformin's ability to inhibit growth in cancer cells and extend lifespan in Caenorhabditis elegans. However, it is unknown whether ACAD10 plays a role in metformin's metabolic actions.

MATERIALS AND METHODS

We assessed the role for ACAD10 on whole-body metabolism and metformin action by generating ACAD10KO mice on a C57BL/6J background via CRISPR-Cas9 technology. In-depth metabolic phenotyping was conducted in both sexes on a normal chow and high fat-high sucrose diet.

RESULTS

Compared with wildtype mice, we detected no difference in body composition, energy expenditure or glucose tolerance in male or female ACAD10KO mice, on a chow diet or high-fat, high-sucrose diet (p ≥ .05). Hepatic mitochondrial function and insulin signalling was not different between genotypes under basal or insulin-stimulated conditions (p ≥ .05). Glucose excursions following acute administration of metformin before a glucose tolerance test were not different between genotypes nor was body composition or energy expenditure altered after 4 weeks of daily metformin treatment (p ≥ .05). Despite the lack of a metabolic phenotype, liver lipidomic analysis suggests ACAD10 depletion influences the abundance of specific ceramide species containing very long chain fatty acids, while metformin treatment altered clusters of cholesterol ester, plasmalogen, phosphatidylcholine and ceramide species.

CONCLUSIONS

Loss of ACAD10 does not alter whole-body metabolism or impact the acute or chronic metabolic actions of metformin in this model.

Acute metformin induces hyperglycemia in healthy adult mourning doves, Zenaida macroura

Birds have the highest blood glucose among vertebrates. Several mechanisms may explain this including the lack of a functional insulin-responsive glucose transport protein, high glucagon concentrations, and reliance on lipid oxidation resulting in the production of gluconeogenic precursors. The hypothesis was that interruption of gluconeogenesis using the diabetes medication metformin would lower glucose concentrations in wild-caught birds. We captured two cohorts of adult mourning doves, Zenaida macroura, and acclimated them to captivity for two weeks. In this crossover study, cohort 1 was administered a single dose of one of the following oral treatments each week: metformin (150 or 300 mg/kg), glycogenolysis inhibitor (2.5 mg/kg 1,4-dideoxy-1,4-imino-D-arabinitol (DAB)), or water (50 μL). Whole blood glucose was measured using a glucometer at baseline, 30, 60, and 120 min following the oral doses. In contrast to mammals and chickens, 300 mg/kg metformin did not alter blood glucose (p > 0.05) whereas 150 mg/kg metformin increased blood glucose compared to water (p = 0.043). To examine whether 150 mg/kg metformin stimulated glycogenolysis, we co-administered 150 mg/kg metformin and 2.5 mg/kg DAB, which prevented the hyperglycemic response. Cohort 2 was administered the same treatments and the early response was examined (0, 5, 10, 15 min). Low-dose metformin increased blood glucose within 5 min (p = 0.039) whereas the high dose had no effect. DAB did not prevent the early response to metformin nor did it alter blood glucose concentrations when administered alone (p = 0.887). In conclusion, metformin increases endogenous blood glucose via glycogenolysis in healthy adult male mourning doves.

Metformin and buparlisib synergistically induce apoptosis of non-small lung cancer (NSCLC) cells via Akt/FoxO3a/Puma axis

Non-small cell lung cancer (NSCLC) is a global health issue lacking effective treatments. Buparlisib is a pan-PI3K inhibitor that shows promising clinical results in treating NSCLC. However, chemoresistance is inevitable and hampers the application of buparlisib. Studies show that a combination of phytochemicals and chemotherapeutics enhances its effectiveness. Here, we evaluated the role of metformin, an agent with multiple pharmacological properties, in enhancing the anti-tumour activities of buparlisib against NSCLC cells. Our results showed that metformin and buparlisib synergistically inhibited cell viability, migration, and invasion of NSCLC cells. In addition, co-treatment of metformin and buparlisib also induced cell cycle arrest and cell death in NSCLC cells. Mechanistically, metformin and buparlisib repressed Mcl-1 and upregulated Puma in NSCLC cells in a p53-independent manner. Moreover, they inhibited the PI3K/Akt signalling pathway, leading to activation of the FoxO3a/Puma signalling in NSCLC cells. Our findings suggest that combined treatment of metformin and buparlisib might provide a promising strategy for treating NSCLC.

A Drug-Drug Interaction Study to Evaluate the Impact of Rimegepant on OCT2- and MATE1-Mediated Transport of Metformin in Healthy Participants

Rimegepant is a calcitonin gene-related peptide receptor antagonist approved for migraine treatment. This phase 1, open-label, single-center, fixed-sequence study evaluated the effect of rimegepant on the pharmacokinetics (PK) of metformin. Twenty-eight healthy participants received metformin 500 mg twice daily from Days 1 to 4 and Days 7 to 10, and once daily on Days 5 and 11. Rimegepant, 75 mg tablet, was administered once daily from Days 9 to 12. At pre-specified time points, plasma metformin concentration, serum glucose levels, and safety and tolerability were evaluated. A 16% increase in the area under the plasma metformin concentration-time curve (AUC) for 1 dosing interval (AUC0-τ,ss), a statistically insignificant increase in maximum and minimum steady-state metformin concentration (Cmax,ss and Cmin,ss), and a decrease in metformin renal clearance were observed on Day 11 following metformin-rimegepant coadministration compared with metformin alone; however, the changes were not clinically relevant. Additionally, coadministration of rimegepant with metformin did not induce clinically meaningful change in the maximum observed glucose concentration (Gmax) or AUCgluc compared with metformin alone. Overall, rimegepant and metformin coadministration did not result in clinically relevant changes in metformin PK, renal clearance, or the antihyperglycemic effects of metformin. Rimegepant is considered safe for use with metformin.

Jin-Gui-Shen-Qi Wan alleviates fibrosis in mouse diabetic nephropathy via MHC class II

ETHNOPHARMACOLOGICAL RELEVANCE

Jin-Gui-Shen-Qi Wan (JGSQW) is a traditional Chinese medicine formula that has been traditionally used to alleviate urinary system ailments such as frequent urination and polyuria. Clinical studies have indicated that when combined with hypoglycaemic drugs, JGSQW exhibits a synergistic effect and can improve diabetic nephropathy (DN), yet its underlying mechanism and targets remain unclear.

AIM OF THE STUDY

This study aims to investigate the therapeutic efficacy of JGSQW and its underlying mechanisms using a DN db/db mouse model.

MATERIALS AND METHODS

Ultrahigh-performance liquid chromatography coupled with mass spectrometry was utilized to analyse the primary active compounds, blood levels, and pharmacokinetics of JGSQW. Additionally, the therapeutic effects of JGSQW and metformin on blood glucose levels, lipid levels, renal function, and renal pathology in diabetic nephropathy mice were investigated using a db/db mouse model. Proteomic analysis was carried out to identify the primary target of JGSQW in treating DN. The mechanism of action was verified by western blotting, immunohistochemistry, and immunofluorescence. Then, molecular docking and molecular dynamics, transfection, drug affinity responsive target stability (DARTS) assay and cell thermal migration assay (CETSA) further validated the targeted binding effect.

RESULTS

JGSQW combined with metformin significantly improved the blood glucose levels, blood lipids, renal function, and renal pathology of DN mice. JGSQW mainly exerted its therapeutic effect on DN by targeting major histocompatibility complex class II (MHC class II) molecules. Immunohistochemistry results showed that JGSQW inhibited the expression of collagen I, fibronectin, and alpha smooth muscle actin (α-SMA) expression. Immunofluorescence and Western blot results showed that JGSQW inhibited the expression of H2-Ab1 and H2-Aa, which are MHC class II molecules, thereby suppressing CD4+ T-cell infiltration and improving diabetic kidney fibrosis. The binding ability of paeoniflorin to H2-Aa was predicted and verified by molecular, DARTS, and CETSA assays. Treatment with 80 μM paeoniflorin effectively alleviated high glucose-induced injury in the MPC-5 injury model. H2-Aa was overexpressed at this model concentration, and Western blotting further confirmed that paeoniflorin reduced glomerular podocyte fibrosis by regulating H2-Aa.

CONCLUSIONS

JGSQW combined with metformin may have a synergistic effect to alleviates renal fibrosis in diabetic nephropathy by downregulating immune complex MHC class II molecules and attenuating the antigen presentation effect of MHC class II on CD4.

A mechanistic exploration of the metabolome of African mango seeds and its potential to alleviate cognitive impairment induced by high-fat/high-carbohydrate diets: Involvement of PI3K/AKT/GSK-3β/CREB, PERK/CHOP/Bcl-2, and AMPK/SIRT-1/mTOR Axes

ETHNOPHARMACOLOGICAL RELEVANCE

Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill., also known as "African mango" or "bush mango", belonging to family Irvingiaceae, has been mostly used as food and traditional medicine for weight loss and to enhance the health.

AIM OF THE STUDY

The overconsumption of high-fat and high-carbohydrate (HFHC) food induces oxidative stress, leading to neurological and cognitive dysfunction. Consequently, there is an immediate need for effective treatment. Hence, this study explored the efficacy of orlistat, metformin, and I. gabonensis seeds' total aqueous extract (IG SAE) in addressing HFHC-induced cognitive impairment by mitigating oxidative stress and their underlying mechanistic pathways.

MATERIALS AND METHODS

Initially, the secondary metabolite profile of IG SAE is determined using high-performance liquid chromatography coupled with a mass detector (UHPLC/MS). The in vivo study involves two phases: an established model phase with control (10 rats on a standard diet) and HFHC diet group (50 rats) for 3 months. In the study phase, HFHC is divided into 5 groups. The first subgroup receives HFHC diet only, while the remaining groups each receive HFHC diet with either Orlistat, metformin, or IG SAE at doses of 100 mg/kg and 200 mg/kg, respectively, for 28 days.

RESULTS

More than 150 phytoconstituents were characterized for the first holistic approach onto IG metabolome. Characterization of IG SAE revealed that tannins dominate metabolites in the plant. Total phenolics and flavonoids were estimated to standardize our extract (77.12 ± 7.09 μg Gallic acid equivalent/mg extract and 8.039 ± 0.53 μg Rutin equivalent/mg extract, respectively). Orlistat, metformin, and IG SAE successfully reduced the body weight, blood glucose level, lipid profile, oxidative stress and neurotransmitters levels leading to improved behavioral functions as well as histological alternation. Also, IG SAE halted inflammation, apoptosis, and endoplasmic reticulum stress, together with promoting autophagy, via modulation of PI3K/AKT/GSK-3β/CREB, PERK/CHOP/Bcl-2 and AMPK/SIRT-1/m-TOR pathways.

CONCLUSION

Metformin, orlistat, and IG SAE offer a promising multi-target therapy to mitigate HFHC diet-induced oxidative stress, addressing cognitive function. This involves diverse molecular mechanisms, particularly the modulation of inflammation, ER stress, and both PI3K/AKT/GSK-3β/CREB and AMPK/SIRT-1/m-TOR pathways. Furthermore, the higher dose of IG SAE demonstrated effects comparable to orlistat and metformin across most studied parameters.

Synthesis and molecular docking studies of new aryl imeglimin derivatives as a potent antidiabetic agent in a diabetic zebrafish model

Diabetes mellitus (DM) is a persistent, progressive, and multifaceted disease characterized by elevated blood glucose levels. Type 2 diabetes mellitus is associated with a relative deficit in insulin mainly due to beta cell dysfunction and peripheral insulin resistance. Metformin has been widely prescribed as a primary treatment option to address this condition. On the other hand, an emerging glucose-reducing agent known as imeglimin has garnered attention due to its similarity to metformin in terms of chemical structure. In this study, an innovative series of imeglimin derivatives, labeled 3(a-j), were synthesized through a one-step reaction involving an aldehyde and metformin. The chemical structures of these derivatives were thoroughly characterized using ESI-MS, 1H, and 13C NMR spectroscopy. In vivo tests on a zebrafish diabetic model were used to evaluate the efficacy of the synthesized compounds. All compounds 3(a-j) showed significant antidiabetic effects. It is worth mentioning that compounds 3b (FBS = 72.3 ± 7.2 mg/dL) and 3g (FBS = 72.7 ± 4.3 mg/dL) have antidiabetic effects comparable to those of the standard drugs metformin (FBS = 74.0 ± 5.1 mg/dL) and imeglimin (82.3 ± 5.2 mg/dL). In addition, a docking study was performed to predict the possible interactions between the synthesized compounds and both SIRT1 and GSK-3β targets. The docking results were in good agreement with the experimental assay results.

Possible role of metformin as an antidepressant in diabetes

OBJECTIVE

Metformin (MET) is a drug used in the treatment of type 2 diabetes due to its insulin receptor sensitizing properties and anti-hepatic gluconeogenesis effect. One of the comorbidities in diabetes is the depression. This review aimed at summarizing the results of the available MET, depression and diabetes studies to clarify the possible role of MET in the depression during diabetes.

METHODS

A bibliographic search on PubMed, Embase, PsycINFO, Web of Science, Cochrane Central for studies referring to MET, depression and diabetes.

RESULTS

Several studies have associated depression to the chronic inflammation that characterizes diabetes. Additionally MET is an anti-inflammatory molecule that generally acts by activating AMPK and inhibiting the NF-kB factor. In the context of diabetes, MET can act directly as an anti-inflammatory drug as well as inhibiting other pro-inflammatory molecules. In this regard, MET may inhibit the pro-inflammatory effects of angiotensin II. By facilitating the action of insulin and reducing hepatic gluconeogenesis, MET reduces circulating glucose levels, decreasing the formation of advanced glycation end products and therefore inflammation. During diabetes, the gut microbiota and the permeability of the intestinal barrier are altered, causing high levels of circulating lipopolysaccharides (LPS), which induce inflammation. MET can normalize the microbiota and the intestinal barrier permeability reducing the levels of LPS and inflammation. Clinical and experimental studies show the anti-depressant effect of MET mediated by different mechanisms both at the peripheral level and in the central nervous system.

CONCLUSION

Therefore, MET as an anti-inflammatory drug can decrease symptoms of depression and represents a therapeutic approach to improve the psychological state of patients with diabetes. Additionally, insulin also has an anti-inflammatory effect that could act together with MET.

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

BACKGROUND

Combining cytotoxic chemotherapy or novel anticancer drugs with T-cell modulators holds great promise in treating advanced cancers. However, the response varies depending on the tumor immune microenvironment (TIME). Therefore, there is a clear need for pharmacologically tractable models of the TIME to dissect its influence on mono- and combination treatment response at the individual level.

METHODS

Here we establish a patient-derived explant culture (PDEC) model of breast cancer, which retains the immune contexture of the primary tumor, recapitulating cytokine profiles and CD8+T cell cytotoxic activity.

RESULTS

We explored the immunomodulatory action of a synthetic lethal BCL2 inhibitor venetoclax+metformin drug combination ex vivo, discovering metformin cannot overcome the lymphocyte-depleting action of venetoclax. Instead, metformin promotes dendritic cell maturation through inhibition of mitochondrial complex I, increasing their capacity to co-stimulate CD4+T cells and thus facilitating antitumor immunity.

CONCLUSIONS

Our results establish PDECs as a feasible model to identify immunomodulatory functions of anticancer drugs in the context of patient-specific TIME.

Metformin Inhibits Zika Virus Infection in Trophoblast Cell Line

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

Development of chitosan lipid nanoparticles to alleviate the pharmacological activity of piperine in the management of cognitive deficit in diabetic rats

The aim of the present study was to prepare and evaluate Piperine (PP) loaded chitosan lipid nanoparticles (PP-CLNPs) to evaluate its biological activity alone or in combination with the antidiabetic drug Metformin (MET) in the management of cognitive deficit in diabetic rats. Piperine was successfully loaded on CLNPs prepared using chitosan, stearic acid, Tween 80 and Tripolyphosphate (TPP) at different concentrations. The developed CLNPs exhibited high entrapment efficiency that ranged from 85.12 to 97.41%, a particle size in the range of 59.56-414 nm and a negatively charged zeta potential values (- 20.1 to - 43.9 mV). In vitro release study revealed enhanced PP release from CLNPs compared to that from free PP suspensions for up to 24 h. In vivo studies revealed that treatment with the optimized PP-CLNPs formulation (F2) exerted a cognitive enhancing effect and ameliorated the oxidative stress associated with diabetes. PP-CLNPs acted as an effective bio-enhancer which increased the potency of metformin in protecting brain tissue from diabetes-induced neuroinflammation and memory deterioration. These results suggested that CLNPs could be a promising drug delivery system for encapsulating PP and thus can be used as an adjuvant therapy in the management of high-risk diabetic cognitive impairment conditions.

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

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

Metformin improves obesity-related oligoasthenospermia via regulating the expression of HSL in testis in mice

Researches have proposed that obesity might contribute to development of oligoasthenospermia. This study was performed to confirm whether obesity contributes to oligoasthenospermia as well as the underlying mechanisms in mice fed with a high fat diet (HFD). Meanwhile, the actions of metformin, a drug of well-known weight-lowering effect, on sperm quality in obese mice were investigated. Our results showed that HFD feeding reduced sperm quality and steroid hormone levels in mice, associated with disruptions in testicular histomorphology and spermatogenesis. Moreover, obesity increased sperm apoptosis. These effects could be prevented by metformin treatment in HFD-fed mice. Mechanistically, an increasement in lipid contents associated with decreased hormone-sensitive lipase (HSL) protein expression in testes in HFD-fed mice was observed, which could be improved by metformin treatment. Then, the model of TM4 mouse Sertoli cells stimulated with palmitic acid (PA) was used to investigate the potential effect of lipid retention on testicular apoptosis and sperm quality reduction. In consistent, PA exposure elevated lipid contents as well as apoptosis in TM4 cells, which could also be improved by metformin treatment. Of note, the protein expression of HSL was reduced stimulated by PA in TM4 cells, also rescued by metformin. Then, anti-apoptosis effect of metformin would be lost with the deficiency of HSL. In summary, our study propose that obesity contributes to oligoasthenospermia by increasing sperm apoptosis induced by impaired lipid hydrolysis due to HSL down-regulation, which could be prevented with metformin treatment via regulating the expression of HSL in testis in mice.

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

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

Metformin normalizes mitochondrial function to delay astrocyte senescence in a mouse model of Parkinson's disease through Mfn2-cGAS signaling

BACKGROUND

Senescent astrocytes play crucial roles in age-associated neurodegenerative diseases, including Parkinson's disease (PD). Metformin, a drug widely used for treating diabetes, exerts longevity effects and neuroprotective activities. However, its effect on astrocyte senescence in PD remains to be defined.

METHODS

Long culture-induced replicative senescence model and 1-methyl-4-phenylpyridinium/α-synuclein aggregate-induced premature senescence model, and a mouse model of PD were used to investigate the effect of metformin on astrocyte senescence in vivo and in vitro. Immunofluorescence staining and flow cytometric analyses were performed to evaluate the mitochondrial function. We stereotactically injected AAV carrying GFAP-promoter-cGAS-shRNA to mouse substantia nigra pars compacta regions to specifically reduce astrocytic cGAS expression to clarify the potential molecular mechanism by which metformin inhibited the astrocyte senescence in PD.

RESULTS

We showed that metformin inhibited the astrocyte senescence in vitro and in PD mice. Mechanistically, metformin normalized mitochondrial function to reduce mitochondrial DNA release through mitofusin 2 (Mfn2), leading to inactivation of cGAS-STING, which delayed astrocyte senescence and prevented neurodegeneration. Mfn2 overexpression in astrocytes reversed the inhibitory role of metformin in cGAS-STING activation and astrocyte senescence. More importantly, metformin ameliorated dopamine neuron injury and behavioral deficits in mice by reducing the accumulation of senescent astrocytes via inhibition of astrocytic cGAS activation. Deletion of astrocytic cGAS abolished the suppressive effects of metformin on astrocyte senescence and neurodegeneration.

CONCLUSIONS

This work reveals that metformin delays astrocyte senescence via inhibiting astrocytic Mfn2-cGAS activation and suggest that metformin is a promising therapeutic agent for age-associated neurodegenerative diseases.

Metformin and chidamide synergistically suppress multiple myeloma progression and enhance lenalidomide/bortezomib sensitivity

Multiple myeloma (MM) is a common hematological malignancy, and patients with MM are recommended to take immunomodulatory drugs such as lenalidomide along with proteasome inhibitors such as bortezomib to extend survival. However, drug resistance influences the efficacy of treatment for MM. In our study, we found that metformin and chidamide both suppressed MM cell growth in a concentration- and time-dependent way (p < .001). Moreover, combined therapy with metformin and chidamide exhibited enhanced inhibition of the growth of MM cells compared with monotherapy (p < .05). Additionally, the triple-drug combination of metformin and chidamide with lenalidomide or bortezomib was used to stimulate the MM cells, and the results revealed that metformin and chidamide treatment sensitized MM cells to lenalidomide and bortezomib. As a result, the apoptosis (p < .001) together with cell cycle arrest at G0/G1 phase (p < .05) was stimulated by lenalidomide and bortezomib, and showed significant elevation in the triple-drug combination group compared with the lenalidomide or bortezomib treatment alone group (p < .05). Furthermore, the impacts of different drugs on glycolysis in MM cells were examined. We found that metformin and chidamide combined treatment significantly promoted glucose uptake and reduced energy production in MM cells treated with lenalidomide and bortezomib (p < .001), suggesting that metformin and chidamide affected glycolysis in MM cells and enhanced the sensitivity of lenalidomide and bortezomib in MM by regulating glucose metabolism. In conclusion, metformin and chidamide synergistically hindered MM cell growth and sensitized cells to lenalidomide/bortezomib. The findings of this study might provide novel clues to improve MM therapy.

Decoding the role of microRNA dysregulation in the interplay of pancreatic cancer and type 2 diabetes

This study examines the complex relationship between pancreatic cancer (PC) and type 2 diabetes (T2D) by focusing on the role of microRNAs (miRNAs). miRNAs are small non-coding RNAs that regulate gene expression and have been implicated in many diseases, including T2D and cancer. To begin, we conducted a literature review to identify miRNAs associated with the PC-T2D link. However, we found limited research on this specific association, with most studies focusing on the antitumor effects of metformin. Furthermore, we performed a bioinformatics analysis to identify new potential miRNAs that might be relevant in the context of PC-T2D. First, we identified miRNAs and gene expression alterations common to both diseases using publicly available datasets. Subsequently, we performed an integrative analysis between the identified miRNAs and genes alterations. As a result, we identified nine miRNAs that could potentially play an important role in the interplay between PC and T2D. These miRNAs have the potential to influence nearby cells and distant tissues, affecting critical processes like extracellular matrix remodeling and cell adhesion, ultimately contributing to the development of T2D or PC. Taken together, these analyses underscore the importance of further exploring the role of miRNAs in the complex interplay of PC and T2D.

Dendropanoxide Attenuates High Glucose-induced Oxidative Damage in NRK-52E Cells via AKT/mTOR Signaling Pathway

Hyperglycemia is a potent risk factor for the development and progression of diabetes-induced nephropathy. Dendropanoxide (DPx) is a natural compound isolated from Dendropanax morbifera (Araliaceae) that exerts various biological effects. However, the role of DPx in hyperglycemia-induced renal tubular cell injury remains unclear. The present study explored the protective mechanism of DPx on high glucose (HG)-induced cytotoxicity in kidney tubular epithelial NRK-52E cells. The cells were cultured with normal glucose (5.6 mM), HG (30 mM), HG + metformin (10 µM), or HG + DPx (10 µM) for 48 h, and cell cycle and apoptosis were analyzed. Malondialdehyde (MDA), advanced glycation end products (AGEs), and reactive oxygen species (ROS) were measured. Protein-based nephrotoxicity biomarkers were measured in both the culture media and cell lysates. MDA and AGEs were significantly increased in NRK-52E cells cultured with HG, and these levels were markedly reduced by pretreatment with DPx or metformin. DPx significantly reduced the levels of kidney injury molecule-1 (KIM-1), pyruvate kinase M2 (PKM2), selenium-binding protein 1 (SBP1), or neutrophil gelatinase-associated lipocalin (NGAL) in NRK-52E cells cultured under HG conditions. Furthermore, treatment with DPx significantly increased antioxidant enzyme activity. DPx protects against HG-induced renal tubular cell damage, which may be mediated by its ability to inhibit oxidative stress through the protein kinase B/mammalian target of the rapamycin (AKT/mTOR) signaling pathway. These findings suggest that DPx can be used as a new drug for the treatment of high glucose-induced diabetic nephropathy.

Evaluation of OCT2-mediated drug-drug interactions between ulotaront and metformin in subjects with schizophrenia

Ulotaront (SEP-363856) is a TAAR1 agonist, with 5-HT1A agonist activity, currently in clinical development for the treatment of schizophrenia. In vitro studies indicate ulotaront is an OCT2-specific inhibitor with IC50 of 1.27 μM. The primary objective of this study is to determine if a single dose of ulotaront affects the PK of metformin, an index substrate of OCT2, in subjects with schizophrenia. In a randomized, single-blind, 2-period crossover study, 25 adults with schizophrenia received a single dose of metformin-HCl 850 mg (approximately 663 mg metformin) with and without coadministration of 100 mg ulotaront. The plasma samples were analyzed by fully validated LC-MS/MS methods. The primary PK endpoints for metformin were AUCinf, AUClast, Cmax, and tmax. The highest-anticipated clinical dose of ulotaront (100 mg) had no statistically significant effect on the PK of a single dose of metformin based on Cmax and AUCinf. Geometric least squares mean ratios were 89.98% and 110.63%, respectively, with the 90% confidential interval (CI) for each parameter contained within 80%-125%. Median tmax was comparable across the treatments. Ulotaront does not act as a perpetrator of OCT2-mediated DDI against metformin. Co-administration of ulotaront is not expected to require dose adjustment of metformin or other drugs cleared by OCT2.

Metabolic effects of SGLT2i and metformin on 3-hydroxybutyric acid and lactate in db/db mice

Combining a Sodium-Glucose-Cotransporter-2-inhibitor (SGLT2i) with metformin is recommended for managing hyperglycemia in patients with type 2 diabetes (T2D) who have cardio-renal complications. Our study aimed to investigate the metabolic effects of SGLT2i and metformin, both individually and synergistically. We treated leptin receptor-deficient (db/db) mice with these drugs for two weeks and conducted metabolite profiling, identifying 861 metabolites across kidney, liver, muscle, fat, and plasma. Using linear regression and mixed-effects models, we identified two SGLT2i-specific metabolites, X-12465 and 3-hydroxybutyric acid (3HBA), a ketone body, across all examined tissues. The levels of 3HBA were significantly higher under SGLT2i monotherapy compared to controls and were attenuated when combined with metformin. We observed similar modulatory effects on metabolites involved in protein catabolism (e.g., branched-chain amino acids) and gluconeogenesis. Moreover, combination therapy significantly raised pipecolate levels, which may enhance mTOR1 activity, while modulating GSK3, a common target of SGLT2i and 3HBA inhibition. The combination therapy also led to significant reductions in body weight and lactate levels, contrasted with monotherapies. Our findings advocate for the combined approach to better manage muscle loss, and the risks of DKA and lactic acidosis, presenting a more effective strategy for T2D treatment.

A novel action of insulin sensitizing drug as a potential promotor of preovulatory follicles, ovulation rate and prolificacy in sheep

The effect of the insulin-sensitizing drug metformin on preovulatory follicle (POF) number, ovulation rate, fetal rate and prolificacy was studied in forty-six cyclic Malpura ewes. After estrus synchronization, the ewes were equally divided into two groups (n = 23). The treatment group (MET) received a daily oral dose of metformin at a rate of 500 mg/animal for approximately 12 weeks, spanning five estrous cycles, as against untreated control (CON). All the ewes were bred to proven rams at the end of treatment. Ovarian ultrasound scans were performed at each estrus and day 9 of each cycle to assess the number and diameter of POFs and corpora lutea (CL), respectively. A comprehensive assessment of circulating hormones including, estradiol, progesterone, androstenedione, and insulin as well as metabolic indicators such as glucose, and lipid profile parameters was performed. At the end of treatment on the day of estrus (E5D0), the treatment showed a stimulatory effect on follicular development with a 53.2% (P < 0.001) increase in the number of POFs. It also increased the ovulation rate by 67.4% (P < 0.01), with a higher proportion (χ2df1 = 10.7, P < 0.001) of ewes in the MET group having multiple ovulations compared to the CON group (82.6 vs. 30.4%). With 1.48 ± 0.12 prolificacy rate in MET ewes, the proportion of ewes giving birth to multiple lambs was 2.9-fold higher than in the CON group. Plasma estradiol, insulin, glucose, total cholesterol, and LDL-cholesterol concentrations were lower (P < 0.05) in the MET ewes than in the CON. The results of the present study indicate that metformin can increase the number of POF, ovulation rate, fetal rate and prolificacy in ewes, while reducing the plasma estradiol, insulin, glucose and cholesterol in MET ewes.

Metformin Treatment Leads to Increased HIV Transcription and Gene Expression through Increased CREB Phosphorylation and Recruitment to the HIV LTR Promoter

Antiretroviral therapy has effectively suppressed HIV infection and replication and prolonged the lifespan of HIV-infected individuals. In the meantime, various complications including type 2 diabetes associated with the long-term antiviral therapy have shown steady increases. Metformin has been the front-line anti-hyperglycemic drug of choice and the most widely prescribed medication for the treatment of type 2 diabetes. However, little is known about the effects of Metformin on HIV infection and replication. In this study, we showed that Metformin treatment enhanced HIV gene expression and transcription in HIV-transfected 293T and HIV-infected Jurkat and human PBMC. Moreover, we demonstrated that Metformin treatment resulted in increased CREB expression and phosphorylation, and TBP expression. Furthermore, we showed that Metformin treatment increased the recruitment of phosphorylated CREB and TBP to the HIV LTR promoter. Lastly, we showed that inhibition of CREB phosphorylation/activation significantly abrogated Metformin-enhanced HIV gene expression. Taken together, these results demonstrated that Metformin treatment increased HIV transcription, gene expression, and production through increased CREB phosphorylation and recruitment to the HIV LTR promoter. These findings may help design the clinical management plan and HIV cure strategy of using Metformin to treat type 2 diabetes, a comorbidity with an increasing prevalence, in people living with HIV.

Therapeutic efficacies of mitochondria-targeted esculetin and metformin in the improvement of age-associated atherosclerosis via regulating AMPK activation

Atherosclerosis, in general, is an age-associated cardiovascular disease wherein a progressive decline in mitochondrial function due to aging majorly contributes to the disease development. Mitochondria-derived ROS due to dysregulated endothelial cell function accentuates the progression of atherosclerotic plaque formation. To circumvent this, mitochondrially targeted antioxidants are emerging as potential candidates to combat metabolic abnormalities. Recently, we synthesized an alkyl TPP+ tagged esculetin (Mito-Esc), and in the current study, we investigated the therapeutic efficacies of Mito-Esc and metformin, a well-known anti-diabetic drug, in the amelioration of age-associated plaque formation in the aortas of 12 months aged Apoe-/- and 20 months aged C57BL/6 mice, in comparison to young C57BL/6 control mice. Administration of Mito-Esc or metformin significantly reduced age-induced atherosclerotic lesion area, macrophage polarization, vascular inflammation, and senescence. Further, chronic passaging of human aortic endothelial cells (HAEC) with either Mito-Esc or metformin significantly delayed cellular senescence via the activation of the AMPK-SIRT1/SIRT6 axis. Conversely, depletion of either AMPK/SIRT1/SIRT6 caused premature senescence. Consistent with this, Mito-Esc or metformin treatment attenuated NFkB-mediated inflammatory signaling and enhanced ARE-mediated anti-oxidant responses in comparison to late passage control HAECs. Importantly, culturing of HAECs for several passages with either Mito-Esc or metformin significantly improved mitochondrial function. Overall, Mito-Esc and metformin treatments delay age-associated atherosclerosis by regulating vascular senescence via the activation of AMPK-SIRT1/SIRT6 axis.

Everolimus decreases [U-13C]glucose utilization by pyruvate carboxylase in breast cancer cells in vitro and in vivo

Reprogrammed metabolism is a hallmark of cancer, but notoriously difficult to target due to metabolic plasticity, especially in response to single metabolic interventions. Combining mTOR inhibitor everolimus and mitochondrial complex 1 inhibitor metformin results in metabolic synergy in in vitro models of triple-negative breast cancer. Here, we investigated whether the effect of this drug combination on tumor size is reflected in changes in tumor metabolism using [U-13C]glucose labeling in an MDA-MB-231 triple negative breast cancer xenograft model. The in vitro effects of everolimus and metformin treatment on oxidative phosphorylation and glycolysis reflected changes in 13C-labeling of metabolites in MDA-MB-231 cells. Treatment of MDA-MB-231 xenografts in SCID/Beige mice with everolimus resulted in slower tumor growth and reduced tumor size and tumor viability by 35%. Metformin treatment moderately inhibited tumor growth but did not enhance everolimus-induced effects. High serum levels of everolimus were reached, whereas levels of metformin were relatively low. Everolimus decreased TCA cycle metabolite labeling and inhibited pyruvate carboxylase activity. Metformin only caused a mild reduction in glycolytic metabolite labeling and did not affect pyruvate carboxylase activity or TCA cycle metabolite labeling. In conclusion, treatment with everolimus, but not metformin, decreased tumor size and viability. Furthermore, the efficacy of everolimus was reflected in reduced 13C-labeling of TCA cycle intermediates and reduced pyruvate carboxylase activity. By using in-depth analysis of drug-induced changes in glucose metabolism in combination with measurement of drug levels in tumor and plasma, effects of metabolically targeted drugs can be explained, and novel targets can be identified.

Effectiveness of metformin for the reversal of cold-ischemia-induced damage in hepatosteatosis

BACKGROUND

Primary dysfunction and rejection are more common in donor liver tissues with steatosis. AMP-activated protein kinase (AMPK) assumes organ-protective functions during ischemia. Metformin was used for the activation of AMPK in hepatocytes. The aim of this study is to investigate the effectiveness of metformin administration for the reversal of cold-ischemia-induced damage in hepatosteatosis.

MATERIAL AND METHODS

Seven-week-old C7BL56 male-mice (n = 109) were separated into four groups depending on diet type and metformin use. A specific diet model was followed for 10 weeks to induce hepatosteatosis. A group of the animals was administered with metformin for the last four weeks via oral gavage. After resection, the liver tissues were perfused and kept for 0-6-12-24 h in the UW solution. Histopathological examinations were performed, and Western blot was utilized to analyze p-AMPK and AMPK expression levels.

RESULTS

Hepatosteatosis decreased significantly with metformin. The steatotic liver group had more prominent pericentral inflammation, necrosis as well as showing a decreased and more delayed AMPK response than the non-fat group. All these alterations could be corrected using metformin.

CONCLUSION

Metformin can increase the resistance of livers with hepatosteatosis to cold-ischemia-induced damage, which in turn may pave the way for successful transplantation of fatty living-donor livers.

In situ evaluation of the impact of metformin or verapamil coadministration with vildagliptin on its regional absorption from the rabbit's intestine

This research aims to identify regional differences in vildagliptin absorption across the intestinal membrane. Furthermore, it was to investigate the effect of verapamil or metformin on vildagliptin absorptive clearance. The study utilized an in situ rabbit intestinal perfusion technique to determine vildagliptin oral absorption from duodenum, jejunum, ileum, and ascending colon. This was conducted both with and without perfusion of metformin or verapamil. The findings revealed that the vildagliptin absorptive clearance per unit length varied by site and was in the order as follows: ileum < jejunum < duodenum < ascending colon, implying that P-gp is significant in the reduction of vildagliptin absorption. Also, the arrangement cannot reverse intestinal P-gp, but the observations suggest that P-gp is significant in reducing vildagliptin absorption. Verapamil co-perfusion significantly increased the vildagliptin absorptive clearance by 2.4 and 3.2 fold through the jejunum and ileum, respectively. Metformin co-administration showed a non-significant decrease in vildagliptin absorptive clearance through all tested segments. Vildagliptin absorption was site-dependent and may be related to the intestinal P-glycoprotein content. This may aid in understanding the important elements that influence vildagliptin absorption, besides drug-drug interactions that can occur in type 2 diabetic patients taking vildagliptin in conjunction with other drugs that can modify the P-glycoprotein level.

Metformin Overcomes the Consequences of NKX3.1 Loss to Suppress Prostate Cancer Progression

BACKGROUND

The antidiabetic drug metformin has known anticancer effects related to its antioxidant activity; however, its clinical benefit for prostate cancer (PCa) has thus far been inconclusive. Here, we investigate whether the efficacy of metformin in PCa is related to the expression status of NKX3.1, a prostate-specific homeobox gene that functions in mitochondria to protect the prostate from aberrant oxidative stress.

OBJECTIVE

To investigate the relationship of NKX3.1 expression and metformin efficacy in PCa.

DESIGN, SETTING, AND PARTICIPANTS

Functional studies were performed in vivo and in vitro in genetically engineered mouse models and human LNCaP cells, and organotypic cultures having normal or reduced/absent levels of NKX3.1. Correlative studies were performed using two independent retrospective tissue microarray cohorts of radical prostatectomies and a retrospective cohort of prostate biopsies from patients on active surveillance.

INTERVENTION

Metformin was administered before or after the induction of oxidative stress by treatment with paraquat.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Functional endpoints included analyses of histopathology, tumorigenicity, and mitochondrial function. Correlative endpoints include Kaplan-Meier curves and Cox proportional hazard regression models.

RESULTS AND LIMITATIONS

Metformin reversed the adverse consequences of NKX3.1 deficiency following oxidative stress in vivo and in vitro, as evident by reduced tumorigenicity and restored mitochondrial function. Patients with low NKX3.1 expression showed a significant clinical benefit from taking metformin.

CONCLUSIONS

Metformin can overcome the adverse consequences of NKX3.1 loss for PCa progression by protecting against oxidative stress and promoting normal mitochondrial function. These functional activities and clinical correlates were observed only with low NKX3.1 expression. Thus, the clinical benefit of metformin in PCa may depend on the status of NKX3.1 expression.

PATIENT SUMMARY

Prostate cancer patients with low NKX3.1 are likely to benefit most from metformin treatment to delay disease progression in a precision interception paradigm.

Antidiabetic Effect of Combined Leaf Extracts of Portulaca oleracea L., Beta vulgaris L., and Cichorium intybus L. in Streptozotocin-Induced Diabetic Rats

Purslane (P), chard (CHA), and chicory (CHI) leaf extracts are individually and traditionally used in the treatment of diabetes mellitus. Polyphenols, flavonoids, the polyphenolic profile of the extracts, and their antioxidant activity were determined. This study evaluated the antidiabetic activity of combinations of these extracts in streptozotocin-induced diabetic rats. Diabetic groups were administered orally and daily for 40 days with the investigated extracts at 250 mg/kg body weight (b.w.) or metformin (100 mg/kg b.w.) as a drug. Fasting blood glucose, oral glucose tolerance, insulin, and fructosamine were assessed. The combined extracts with high levels of P or CHI exerted potent hypoglycemic activity compared with metformin in addition to the restoration of the histopathological changes in the liver and pancreas of diabetic rats to a near-normal state. Therefore, these combined extracts could be developed as natural drugs for diabetes.

Metformin role in Parkinson's disease: a double-sword effect

Parkinson's disease (PD) is a common neurodegenerative disease developed due to the degeneration of dopaminergic neurons in the substantia nigra. There is no single effective treatment in the management of PD. Therefore, repurposing effective and approved drugs like metformin could be an effective strategy for managing PD. However, the mechanistic role of metformin in PD neuropathology was not fully elucidated. Metformin is an insulin-sensitizing agent used as a first-line therapy in the management of type 2 diabetes mellitus (T2DM) and has the ability to reduce insulin resistance (IR). Metformin may have a beneficial effect on PD neuropathology. The neuroprotective effect of metformin is mainly mediated by activating adenosine monophosphate protein kinase (AMPK), which reduces mitochondrial dysfunction, oxidative stress, and α-synuclein aggregation. As well, metformin mitigates brain IR a hallmark of PD and other neurodegenerative diseases. However, metformin may harm PD neuropathology by inducing hyperhomocysteinemia and deficiency of folate and B12. Therefore, this review aimed to find the potential role of metformin regarding its protective and detrimental effects on the pathogenesis of PD. The mechanistic role of metformin in PD neuropathology was not fully elucidated. Most studies regarding metformin and its effectiveness in PD neuropathology were observed in preclinical studies, which are not fully translated into clinical settings. In addition, metformin effect on PD neuropathology was previously clarified in T2DM, potentially linked to an increasing PD risk. These limitations hinder the conclusion concerning the therapeutic efficacy of metformin and its beneficial and detrimental role in PD. Therefore, as metformin does not cause hypoglycemia and is a safe drug, it should be evaluated in non-diabetic patients concerning PD risk.

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

OBJECTIVE

Non-small-cell lung cancer (NSCLC) is a deadly form of cancer that exhibits extensive intercellular communication which contributed to chemoradiotherapy resistance. Recent evidence suggests that arrange of key proteins are involved in lung cancer progression, including gap junction proteins (GJPs).

METHODS AND RESULTS

In this study, we examined the expression patterns of GJPs in NSCLC, uncovering that both gap junction protein, beta 2 (GJB2) and gap junction protein, beta 2 (GJB3) are increased in LUAD and LUSC. We observed a correlation between the upregulation of GJB2, GJB3 in clinical samples and a worse prognosis in patients with NSCLC. By examining the mechanics, we additionally discovered that nuclear factor erythroid-2-related factor 1 (NFE2L1) had the capability to enhance the expression of connexin26 and connexin 31 in the NSCLC cell line A549. In addition, the use of metformin was discovered to cause significant downregulation of gap junction protein, betas (GJBs) by limiting the presence of NFE2L1 in the cytoplasm.

CONCLUSION

This emphasizes the potential of targeting GJBs as a viable treatment approach for NSCLC patients receiving metformin.

Modulating the antibacterial effect of the existing antibiotics along with repurposing drug metformin

Owing to the extensive prevalence of resistant bacteria to numerous antibiotic classes, antimicrobial resistance (AMR) poses a well-known hazard to world health. As an alternate approach in the field of antimicrobial drug discovery, repurposing the available medications which are also called antibiotic resistance breakers has been pursued for the treatment of infections with antimicrobial resistance pathogens. In this study, we used Haloperidol, Metformin and Hydroxychloroquine as repurposing drugs in in vitro (Antibacterial Antibiotic Sensitivity Test and Minimum Inhibitory Concentration-MIC) and in vivo (Shigellosis in Swiss albino mice) tests in combination with traditional antibiotics (Oxytetracycline, Erythromycin, Doxycycline, Gentamicin, Ampicillin, Chloramphenicol, and Penicillin) against a group of AMR resistance bacteria (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Shigella boydii). After observing the results of the conducted in vitro experiments we studied the effects of the above non antibiotic drugs in combination with the said antibiotics. As an repurposing adjuvant antibiotic drug, Metformin exhibited noteworthy activity in almost all in vitro, in vivo and in silico tests (Zone of inhibition for 30 to 43 mm for E.coli in combination with Doxycycline; MIC value decreased 50 µM to 0.781 µM with Doxycycline on S. boydii).In rodents Doxycycline and Metformin showed prominent against Shigellosis in White blood cell count (6.47 ± 0.152 thousand/mm3) and Erythrocyte sedimentation rate (10.5 ± 1.73 mm/hr). Our findings indicated that Metformin and Doxycycline combination has a crucial impact on Shigellosis. The molecular docking study was performed targeting the Acriflavine resistance protein B (AcrB) (PDB ID: 4CDI) and MexA protein (PDB ID: 6IOK) protein with Metformin (met8) drug which showed the highest binding energy with - 6.4 kcal/mol and - 5.5 kcal/mol respectively. Further, molecular dynamics simulation revealed that the docked complexes were relatively stable during the 100 ns simulation period. This study suggest Metformin and other experimented drugs can be used as adjuvants boost up antibiosis but further study is needed to find out the safety and efficacy of this non-antibiotic drug as potent antibiotic adjuvant.

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

OBJECTIVE

To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer.

METHODS

Tumor associated fibroblasts (CAFs) co-cultured with breast cancer cells were treated with metformin, and the changes in expressions of hypoxia-inducible factor-1α (HIF-1α), p-AMPK, stroma-derived factor-1 (SDF-1) and interleukin-8 (IL-8) in the CAFs were detected using ELISA, RT-qPCR or Western blotting; Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1, IL-8 and TGF-β1. The effects of HIF-1α shRNA or overexpression plasmid, AMPK shRNA, and treatment with OG (a proline hydroxylase inhibitor) or 2-OXO (a proline hydroxylase activator) were examined on p-AMPK, HIF-1α, SDF-1 and IL-8 expressions and invasiveness of the CAFs.

RESULTS

Metformin treatment significantly increased the expression levels of p-AMPK, SDF-1 and IL-8 (P<0.05) and decreased HIF-1α expression (P<0.05) without affecting AMPK expression level (P>0.05) in the CAFs. The invasion ability of metformintreated breast cancer cells was significantly decreased (P<0.05). Exogenous SDF-1 and IL-8, HIF-1α overexpression, and OGinduced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion (P<0.05) and HIF-1α, SDF-1 and IL-8 expressions in CAFs (P<0.05). Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells (P<0.05). P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells (P<0.05). Treatment with TGF-β1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells (P<0.05).

CONCLUSION

Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.

[Metformin ameliorates PM2.5-induced functional impairment of placental trophoblasts by inhibiting ferroptosis]

OBJECTIVE

To investigate the protective effect of metformin against PM2.5-induced functional impairment of placental trophoblasts and explore the underlying mechanism.

METHODS

Sixteen pregnant Kunming mice were randomly assigned into two groups (n=8) for intratracheal instillation of PBS or PM2.5 suspension at 1.5, 7.5, and 12.5 days of gestation. The pregnancy outcome of the mice was observed, and placental zonal structure and vascular density of the labyrinth area were examined with HE staining, followed by detection of ferroptosis-related indexes in the placenta. In cultured human trophoblasts (HTR8/SVneo cells), the effects of PM2.5 exposure and treatment with metformin on cell viability, proliferation, migration, invasion, and tube formation ability were evaluated using CCK8 assay, EDU staining, wound healing assay, Transwell experiment, and tube formation experiment; the cellular expressions of ferroptosis-related proteins were analyzed using ELISA and Western blotting.

RESULTS

M2.5 exposure of the mice during pregnancy resulted in significantly decreased weight and number of the fetuses and increased fetal mortality with a reduced placental weight (all P<0.001). PM2.5 exposure also caused obvious impairment of the placental structure and trophoblast ferroptosis. In cultured HTR8/SVneo cells, PM2.5 significantly inhibited proliferation, migration, invasion, and angiogenesis of the cells by causing ferroptosis. Metformin treatment obviously attenuated PM2.5-induced inhibition of proliferation, migration, invasion, and angiogenesis of the cells, and effectively reversed PM2.5-induced ferroptosis in the trophoblasts as shown by significantly increased intracellular GSH level and SOD activity, reduced MDA and Fe2+ levels, and upregulated GPX4 and SLC7A11 protein expression (P<0.05 or 0.01).

CONCLUSION

PM2.5 exposure during pregnancy causes adverse pregnancy outcomes and ferroptosis and functional impairment of placental trophoblasts in mice, and metformin can effectively alleviate PM2.5-induced trophoblast impairment.

Anti-ENO1 antibody combined with metformin against tumor resistance: a novel antibody-based platform

Background

Antibody-based platforms (i.e., ADC) have emerged as one of the most encouraging tools for the cancer resistance caused by cancer stem cells (CSCs) enrichment. Our study might provide a promising therapeutic direction against drug resistance and serve as a potential precursor platform for screening ADC.

Methods

The cell migration, invasion, drug resistance, and self-renewal were assessed by the cell invasion and migration assay, wound healing assay, CCK-8 assay, colony formation assay, and sphere formation assay, respectively. The expression profiles of CSCs (ALDH+ and CD44+) subpopulations were screened by flow cytometry. The western blot and cell immunofluorescence assay were used to evaluate pathway-related protein expression in both anti-ENO1 antibody, MET combined with DPP/CTX-treated CSCs.

Results

In the present study, western blot and flow cytometry verified that anti-ENO1 antibody target the CD44+ subpopulation by inhibiting the PI3K/AKT pathway, while metformin might target the ALDH+ subpopulation through activation of the AMPK pathway and thus reverse drug resistance to varying degrees. Subsequently, in vitro investigation indicated that anti-ENO1 antibody, metformin combined with cisplatin/cetuximab could simultaneously target ALDH+ and CD44+ subpopulations. The combination also inhibited the CSCs proliferation, migration, invasion, and sphere formation; which may result in overcoming the drug resistance. Then, molecular mechanism exploration verified that the anti-ENO1 antibody, metformin combined with cisplatin/cetuximab inhibited the Wnt/β-catenin signaling.

Conclusions

The study preliminarily revealed anti-ENO1 antibody combined with metformin could overcome drug resistance against CSCs by inhibiting the Wnt//β-catenin pathway and might serve as a potential precursor platform for screening ADC. More importantly, it is reasonably believed that antibody-based drug combination therapy might function as an encouraging tool for oncotherapy.

Metformin switches cell death modes to soothe the apical periodontitis via ZBP1

Apical periodontitis (AP) is a disease caused by pathogenic microorganisms and featured with the degradation of periapical hard tissue. Our recent research showed the crucial role of Z-DNA binding protein 1 (ZBP1)-mediated necroptosis and apoptosis in the pathogenesis of AP. However, the specific regulatory mechanisms of ZBP1 in AP are not fully elucidated. It was found that metformin has a regulatory role in cell necroptosis and apoptosis. But whether and how metformin regulates necroptosis and apoptosis through the ZBP1 in the context of AP remains unknown. This study provided evidence that lipopolysaccharide (LPS) promotes the synthesis of left-handed Z-nucleic acids (Z-NA), which in turn activates ZBP1. Knockout of Zbp1 by CRISPR/Cas9 technology significantly reduced LPS-induced necroptosis and apoptosis in vitro. By using Zbp1-knockout mice, periapical bone destruction was alleviated. Moreover, type I interferon induced the expression of interferon-stimulated genes (ISGs), which serve as a major source of Z-NA. In addition, the RNA-editing enzyme Adenosine Deaminase RNA specific 1 (ADAR1) prevented the accumulation of endogenous Z-NA. Meanwhile, metformin suppressed the ZBP1-mediated necroptosis by inhibiting the expression of ZBP1 and the accumulation of ISGs. Metformin also promoted mitochondrial apoptosis, which is critical for the elimination of intracellular bacterial infection. The enhanced apoptosis further promoted the healing of infected apical bone tissues. In summary, these results demonstrated that the recognition of Z-NA by ZBP1 plays an important role in AP pathogenesis. Metformin suppressed ZBP1-mediated necroptosis and promoted apoptosis, thereby contributing to the soothing of inflammation and bone healing in AP.

Evaluating synergistic effects of metformin and simvastatin on ovarian cancer cells

BACKGROUND

Ovarian Cancer (OC) stands as the most lethal gynecological malignancy, presenting an urgent clinical challenge in the quest to improve response rates. One approach to address this challenge is through drug repurposing, exemplified by the investigation of metabolic-modulating drugs such as Metformin (MTF) and Simvastatin (SIM). This study aims to explore the molecular mechanisms contributing to the potential synergistic anti-cancer effects between MTF and SIM on ovarian cancer cells.

METHODS

We assessed the effects of the combination on the proliferation and viability of two cell lines OVCAR-3 and SKOV-3. IC50 concentrations of MTF and SIM were determined using a proliferation assay, followed by subtoxic concentrations to explore the potential synergistic effects on the viability of both cell lines. Transcriptomic analysis was conducted on OVCAR-3 treated cells, and the findings were validated by assessing the expression levels of differentially expressed genes (DEGs) through real-time PCR in both cell lines SK-OV-3 and OVCAR-3.

RESULTS

Cytotoxicity analysis guided the selection of treatment concentrations as such MTF 10 mM and SIM 5 μM. The combined treatment of MTF and SIM demonstrated a synergistic inhibition of proliferation and viability in both cell lines. In OVCAR-3, exclusive identification of 507 DEGs was seen in the combination arm. Upregulation of FOXO3, RhoA, and TNFα, along with downregulation of PIK3R1, SKP2, and ATP6V1D levels, was observed in OVCAR-3 treated cells. Real-time PCR validation confirmed the consistency of expression levels for the mentioned DEGs.

CONCLUSION

Our data strongly supports the presence of synergy between MTF and SIM in OC cells. The combination's effect is associated with the dysregulation of genes in the key regulators AMPK and mTOR alongside other interconnected pathways.

Just a spoonful of metformin helps the medicine go down

Diffuse intrinsic pontine glioma (DIPG) is a devastating brain tumor with a need for novel therapies. So far, monotherapies have failed to prolong survival for these patients, and combinatorial strategies have often shown severe, dose-limiting toxicities. In this issue of the JCI, Duchatel, Jackson, and colleagues address this challenge by introducing a drug combination that mitigates side effects and overcomes resistance. After identifying the PI3K/mTOR pathway as a therapeutic vulnerability, they treated DIPG-bearing mice with paxalisib and saw responses but also observed hyperglycemia as a severe side effect. Combining paxalisib with metformin mitigated this toxicity, but also upregulated protein kinase C (PKC) signaling. To tackle this mechanism of resistance, the authors added the PKC inhibitor enzastaurin to their drug combination and showed that this triple therapy led to improved survival. This approach paves the way for improved outcomes for patients with DIPG and other brain tumors.

Gut microbiota-derived gamma-aminobutyric acid from metformin treatment reduces hepatic ischemia/reperfusion injury through inhibiting ferroptosis

Hepatic ischemia/reperfusion injury (HIRI) is a common and inevitable factor leading to poor prognosis in various liver diseases, making the outcomes of current treatments in clinic unsatisfactory. Metformin has been demonstrated to be beneficial to alleviate HIRI in recent studies, however, the underpinning mechanism remains unclear. In this study, we found metformin mitigates HIRI-induced ferroptosis through reshaped gut microbiota in mice, which was confirmed by the results of fecal microbiota transplantation treatment but showed the elimination of the beneficial effects when gut bacteria were depleted using antibiotics. Detailedly, through 16S rRNA and metagenomic sequencing, we identified that the metformin-reshaped microbiota was characterized by the increase of gamma-aminobutyric acid (GABA) producing bacteria. This increase was further confirmed by the elevation of GABA synthesis key enzymes, glutamic acid decarboxylase and putrescine aminotransferase, in gut microbes of metformin-treated mice and healthy volunteers. Furthermore, the benefit of GABA against HIRI-induced ferroptosis was demonstrated in GABA-treated mice. Collectively, our data indicate that metformin can mitigate HIRI-induced ferroptosis by reshaped gut microbiota, with GABA identified as a key metabolite.

BNC1 deficiency induces mitochondrial dysfunction-triggered spermatogonia apoptosis through the CREB/SIRT1/FOXO3 pathway: the therapeutic potential of nicotinamide riboside and metformin†

Male infertility is a global health problem that disturbs numerous couples worldwide. Basonuclin 1 (BNC1) is a transcription factor mainly expressed in proliferative keratinocytes and germ cells. A frameshift mutation of BNC1 was identified in a large Chinese primary ovarian insufficiency pedigree. The expression of BNC1 was significantly decreased in the testis biopsies of infertile patients with nonobstructive azoospermia. Previous studies have revealed that mice with BNC1 deficiency are generally subfertile and undergo gradual spermatogenic failure. We observed that apoptosis of spermatogonia is tightly related to spermatogenic failure in mice with a Bnc1 truncation mutation. Such impairment is related to mitochondrial dysfunction causing lower mitochondrial membrane potential and higher reactive oxygen species. We showed that downregulation of CREB/SIRT1/FOXO3 signaling participates in the above impairment. Administration of nicotinamide riboside or metformin reversed mitochondrial dysfunction and inhibited apoptosis in Bnc1-knockdown spermatogonia by stimulating CREB/SIRT1/FOXO3 signaling. Dietary supplementation with nicotinamide riboside or metformin in mutated mice increased SIRT1 signaling, improved the architecture of spermatogenic tubules, inhibited apoptosis of the testis, and improved the fertility of mice with a Bnc1 truncation mutation. Our data establish that oral nicotinamide riboside or metformin can be useful for the treatment of spermatogenic failure induced by Bnc1 mutation.

Antidiabetic drug administration prevents bone mineral density loss: Evidence from a two-sample Mendelian randomization study

The aim of this study was to investigate the effect of common antidiabetic drugs on BMD by two-sample Mendelian randomization (MR). The single nucleotide polymorphisms that were strongly associated with insulin, metformin, rosiglitazone and gliclazide were extracted as instrumental variables (IVs) for MR analysis. The inverse variance weighted (IVW) method was used as the primary MR method to assess the causal effect of antidiabetic drugs on BMD, and other MR methods, including Weighted median, MR Egger and Weighted mode, were used for complementary analysis. Reliability and stability were assessed by the leave-one-out test. In the present work, IVW estimation of the causal effect of insulin on heel BMD demonstrated that there was a null effect of insulin on heel BMD (β = 0.765; se = 0.971; P = 0.430), while metformin treatment had a positive effect on heel BMD (β = 1.414; se = 0.460; P = 2.118*10-3). The causal relationship between rosiglitazone and heel BMD analysed by IVW suggested that there was a null effect of rosiglitazone on heel BMD (β = -0.526; se = 1.744; P = 0.763), but the causal effect of gliclazide on heel BMD evaluated by IVW demonstrated that there was a positive effect of gliclazide on heel BMD (β = 2.671; se = 1.340; P = 0.046). In summary, the present work showed that metformin and gliclazide have a role in reducing BMD loss in patients with diabetes and are recommended for BMD loss prevention in diabetes.

Metformin improves nonalcoholic fatty liver disease in db/db mice by inhibiting ferroptosis

Nonalcoholic fatty liver disease (NAFLD) is the primary complication of type 2 diabetes (T2DM)-related liver disease, lacking effective treatment options. Metformin (Met), a widely prescribed anti-hyperglycemic medication, has been found to protect against NAFLD. Ferroptosis, a newly discovered form of cell death, is associated with the development of NAFLD. Despite this association, the extent of Met's protective effects on NAFLD through the modulation of ferroptosis has yet to be thoroughly investigated. In the present study, the administration of erastin or Ras-selective lethal 3 (RSL3), both known ferroptosis inducers, resulted in elevated cell mortality and reduced cell viability in AML12 hepatocytes. Notably, Met treatment demonstrated the capacity to mitigate these effects. Furthermore, we observed increased ferroptosis levels in both AML12 hepatocytes treated with palmitate and oleate (PA/OA) and in the liver tissue of db/db mice. Met treatment demonstrated significant reductions in iron accumulation and lipid-related reactive oxygen species production, simultaneously elevating the glutathione/glutathione disulfide ratio in both PA/OA-treated AML12 hepatocytes and the liver tissue of db/db mice. Interestingly, the anti-ferroptosis effects of Met were significantly reversed with the administration of RSL3, both in vitro and in vivo. Mechanistically, Met treatment regulated the glutathione peroxidase 4/solute carrier family 7 member 11/acyl-CoA synthetase long-chain family member 4 axis to alleviate ferroptosis in NAFLD hepatocytes. Overall, our findings highlight the crucial role of ferroptosis in the development of T2DM-related NAFLD and underscore the potential of Met in modulating key factors associated with ferroptosis in the context of NAFLD.

(-)-Epicatechin and colonic metabolite 2,3-dihydroxybenzoic acid, alone or in combination with metformin, protect cardiomyocytes from high glucose/high palmitic acid-induced damage by regulating redox status, apoptosis and autophagy

(-)-Epicatechin (EC) and a main colonic phenolic acid derived from flavonoid intake, 2,3-dihydroxybenzoic acid (DHBA), display antioxidant and antidiabetic activities. Diabetic cardiomyopathy (DCM) is one of the main causes of mortality in patients with diabetes, lacking a suitable treatment. Hyperglycaemia and dyslipidaemia are mainly responsible for oxidative stress and altered apoptosis and autophagy in cardiomyocytes during DCM. In this context, phenolic compounds could be suitable candidates for alleviating DCM, but have scarcely been investigated or their use in combination with antidiabetic drugs. This study evaluates the effects of EC, DHBA and antidiabetic drug metformin (MET), alone or all combined (MIX), on redox status, autophagy and apoptosis in H9c2 cardiomyocytes challenged with high concentrations of glucose (HG) and palmitic acid (PA). Under HG + PA conditions, EC, DHBA, MET and MIX equally improved redox status, reduced apoptosis induction and ameliorated autophagy inhibition. Mechanistically, all treatments alleviated HG + PA-induced oxidative stress by reinforcing antioxidant defences (∼40% increase in glutathione, ∼30% diminution in GPx activity and ∼15% increase in SOD activity) and reducing ROS generation (∼20%), protein oxidation (∼35%) and JNK phosphorylation (∼200%). Additionally, all treatments mitigated HG + PA-induced apoptosis and activated autophagy by decreasing Bax (∼15-25%), caspase-3 (∼20-40%) and p62 (∼20-40%), and increasing Bcl-2, beclin-1 and LC3-II/LC3-I (∼40-60%, ∼15-20%, and ∼25-30%, respectively). JNK inhibition improved protective changes to redox status, apoptosis and autophagy that were observed in EC-, DHBA- and MIX-mediated protection. Despite no additive or synergistic effects being detected when phenolic compounds and MET were combined, these results provide the first evidence for the benefits of EC and DHBA, comparable to those of MET alone, to ameliorate cardiomyocyte damage, that involve an improvement in antioxidant competence, autophagy and apoptosis, these effects being mediated at least by targeting JNK.

Metformin, Cognitive Function, and Changes in the Gut Microbiome

The decline in cognitive function and the prevalence of neurodegenerative disorders are among the most serious threats to health in old age. The prevalence of dementia has reached 50 million people worldwide and has become a major public health problem. The causes of age-related cognitive impairment are multiple, complex, and difficult to determine. However, type 2 diabetes (T2D) is linked to an enhanced risk of cognitive impairment and dementia. Human studies have shown that patients with T2D exhibit dysbiosis of the gut microbiota. This dysbiosis may contribute to the development of insulin resistance and increased plasma lipopolysaccharide concentrations. Metformin medication mimics some of the benefits of calorie restriction and physical activity, such as greater insulin sensitivity and decreased cholesterol levels, and hence may also have a positive impact on aging in humans. According to recent human investigations, metformin might partially restore gut dysbiosis related to T2D. Likewise, some studies showed that metformin reduced the risk of dementia and improved cognition, although not all studies are concordant. Therefore, this review focused on those human studies describing the effects of metformin on the gut microbiome (specifically the changes in taxonomy, function, and circulating metabolomics), the changes in cognitive function, and their possible bidirectional implications.