The intersection of metformin and inflammation

Irisin attenuates acute glaucoma-induced neuroinflammation by activating microglia-integrin αVβ5/AMPK and promoting autophagy

Neuroinflammation, characterized by microglial activation and the release of multiple inflammatory mediators, is a key factor in acute glaucomatous injury leading to retinal ganglion cell (RGC) death and ultimately irreversible vision loss. Irisin, a novel exercise-induced myokine, has demonstrated anti-inflammatory activity in ischemia/reperfusion injuries across multiple organs and has displayed a significant neuroprotective role in experimental stroke disease models. This study examined the protective impact of irisin and investigated its potential mechanism involved in this process utilizing an acute ocular hypertension (AOH)-induced retinal injury model in mice and a microglia inflammation model induced by lipopolysaccharide (LPS). There was a transient downregulation of irisin in the retina after AOH injury, with parallel emergence of retinal neuroinflammation and RGC death. Irisin attenuated retinal and optic nerve damage and promotes the phenotypic conversion of microglia from M1 to M2. Mechanistically, irisin significantly upregulated the expression of integrin αVβ5, p-AMPK, and autophagy-related markers. Integrin αVβ5 was highly expressed on microglia but hardly expressed on RGC. The integrin αVβ5 inhibitor cilengitide, the AMPK inhibitor dorsomorphin, and the autophagy inhibitor 3-Methyladenine (3-MA) blocked the neuroprotective effects of irisin. Our results suggest irisin attenuates acute glaucoma-induced neuroinflammation and RGC death by activating integrin αVβ5/AMPK in microglia and promoting autophagy. It should be considered a potential neuroprotective therapy for acute glaucoma.

The role of cytokines in the pathogenesis of SAPHO syndrome

SAPHO syndrome is a complex inflammatory disorder affecting the skin and bones, characterized by osteomyelitis, acne, and pustulosis. Cytokines play a pivotal role in the pathogenesis of SAPHO syndrome, especially in inflammatory responses and immune regulation. This article reviews the cytokines involved in the pathogenesis of SAPHO syndrome, such as tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), IL-6, IL-10, and transforming growth factor-β (TGF-β), and discusses their potential as intervention points for treatment. These findings elucidate the intricate immune regulatory network of SAPHO syndrome and provide a theoretical foundation for the development of new targeted therapeutic strategies.

Metformin Alleviates Inflammation and Induces Mitophagy in Human Retinal Pigment Epithelium Cells Suffering from Mitochondrial Damage

Mitochondrial malfunction, excessive production of reactive oxygen species (ROS), deficient autophagy/mitophagy, and chronic inflammation are hallmarks of age-related macular degeneration (AMD). Metformin has been shown to activate mitophagy, alleviate inflammation, and lower the odds of developing AMD. Here, we explored the ability of metformin to activate mitophagy and alleviate inflammation in retinal pigment epithelium (RPE) cells. Human ARPE-19 cells were pre-treated with metformin for 1 h prior to exposure to antimycin A (10 µM), which induced mitochondrial damage. Cell viability, ROS production, and inflammatory cytokine production were measured, while autophagy/mitophagy proteins were studied using Western blotting and immunocytochemistry. Metformin pre-treatment reduced the levels of proinflammatory cytokines IL-6 and IL-8 to 42% and 65% compared to ARPE-19 cells exposed to antimycin A alone. Metformin reduced the accumulation of the autophagy substrate SQSTM1/p62 (43.9%) and the levels of LC3 I and II (51.6% and 48.6%, respectively) after antimycin A exposure. Metformin also increased the colocalization of LC3 with TOM20 1.5-fold, suggesting active mitophagy. Antimycin A exposure increased the production of mitochondrial ROS (226%), which was reduced by the metformin pre-treatment (84.5%). Collectively, metformin showed anti-inflammatory and antioxidative potential with mitophagy induction in human RPE cells suffering from mitochondrial damage.

Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?

Metformin is a widely employed drug in type 2 diabetes. In addition to warranting good short- and long-term glycemic control, metformin displays many intriguing properties as protection against cardiovascular and neurodegenerative diseases, anti-tumorigenic and longevity promotion. In addition to being a low-cost drug, metformin is generally well tolerated. However, despite the enthusiastic drive to aliment these novel studies, many contradictory results suggest the importance of better elucidating the complexity of metformin action in different tissues/cells to establish its possible employment in neurodegenerative diseases. This review summarises recent data identifying lysosomal-dependent processes and lysosomal targets, such as endosomal Na+/H+ exchangers, presenilin enhancer 2 (PEN2), the lysosomal pathway leading to AMP-activated protein kinase (AMPK) activation, and the transcription factor EB (TFEB), modulated by metformin. Lysosomal dysfunctions resulting in autophagic and lysosomal acidification and biogenesis impairment appear to be hallmarks of many inherited and acquired neurodegenerative diseases. Lysosomes are not yet seen as a sort of cellular dump but are crucial in determining key signalling paths and processes involved in the clearance of aggregated proteins. Thus, the possibility of pharmacologically modulating them deserves great interest. Despite the potentiality of metformin in this context, many additional important issues, such as dosing, should be addressed in the future.

Metformin in Chemoprevention of Lung Cancer: A Retrospective Population-Based Cohort Study in Lithuania

Background and Objectives: This study aimed to evaluate the potential chemopreventive effect of antidiabetic medications, specifically metformin and pioglitazone, on lung cancer in patients with type 2 diabetes mellitus (T2DM). Additionally, the potential dose-response relationship for metformin use was analyzed. Methods: We conducted a retrospective cohort study utilizing comprehensive national health insurance and cancer registry databases to gather a large cohort of T2DM patients. Cox proportional hazards regression models were used to assess the risk of lung cancer across different antidiabetic medication groups, adjusting for potential confounders such as age and gender. A dose-response analysis was conducted for metformin users. Results: Our results indicated that metformin users had a significantly lower lung cancer risk than the reference group (HR = 0.69, 95% CI [0.55-0.86], p = 0.001). The risk reduction increased with higher cumulative metformin doses: a metformin cumulative dose between 1,370,000 and 2,976,000 had an HR of 0.61 (95% CI [0.49-0.75], p < 0.001) vs. cumulative metformin dose >2,976,000 which had an HR of 0.35 (95% CI [0.21-0.59], p < 0.001). No significant association between pioglitazone use and the risk of lung cancer was found (HR = 1.00, 95% CI [0.25-4.02]). Conclusions: This study shows that metformin may have a dose-dependent chemopreventive effect against lung cancer in T2DM, while the impact of pioglitazone remains unclear and requires further investigation.

Nutritional and metabolic modulation of inflammation in critically ill patients: a narrative review of rationale, evidence and grey areas

BACKGROUND

Inflammation is the hallmark of critical illness and triggers the neuro-endocrine stress response and an oxidative stress. Acute inflammation is initially essential for patient's survival. However, ongoing or exaggerated inflammation, due to persistent organ dysfunction, immune dysfunction or poor inflammation resolution, is associated to subsequent hypermetabolism and hypercatabolism that severely impact short and long-term functional status, autonomy, as well as health-related costs. Modulation of inflammation is thus tempting, with the goal to improve the short- and long-term outcomes of critically ill patients.

FINDINGS

Inflammation can be modulated by nutritional strategies (including the timing of enteral nutrition initiation, the provision of some specific macronutrients or micronutrients, the use of probiotics) and metabolic treatments. The most interesting strategies seem to be n-3 polyunsaturated fatty acids, vitamin D, antioxidant micronutrients and propranolol, given their safety, their accessibility for clinical use, and their benefits in clinical studies in the specific context of critical care. However, the optimal doses, timing and route of administration are still unknown for most of them. Furthermore, their use in the recovery phase is not well studied and defined.

CONCLUSION

The rationale to use strategies of inflammation modulation is obvious, based on critical illness pathophysiology and based on the increasingly described effects of some nutritional and pharmacological strategies. Regretfully, there isn't always substantial proof from clinical research regarding the positive impacts directly brought about by inflammation modulation. Some arguments come from studies performed in severe burn patients, but such results should be transposed to non-burn patients with caution. Further studies are needed to explore how the modulation of inflammation can improve the long-term outcomes after a critical illness.

Metformin as a Therapeutic Agent for Obesity-Associated Immune Dysfunction

Obesity is associated with impaired immune function, characterized by inflammation, and leading to poor response to infection, impaired vaccine response, increased susceptibility to autoimmune disease, and increased risk of cancer and cancer mortality. Worse, there is evidence that weight loss alone may be insufficient to reverse the immune dysfunction caused by obesity. It is therefore critically important to identify alternative therapeutic approaches to decrease the negative effects of obesity-associated inflammation. In this article, we will review evidence that the antidiabetic drug metformin may be considered as a therapeutic agent for obesity-associated immune dysfunction. Metformin has immunomodulatory effects, stimulating or suppressing the immune response in both a cell-specific and disease-specific manner. Although the mechanism of action of metformin on the immune system remains to be fully elucidated, there is strong evidence that metformin enters select immune cells and disrupts electron transport, leading to both AMP-activated protein kinase (AMPK)-dependent and AMPK-independent effects on immune cell differentiation and cytokine production. These effects of metformin on immune cells have been shown to improve immune responses to infection, autoimmunity, and cancer.

Metformin: Therapeutic profile in the treatment of type 2 diabetes

Metformin (dimethyl-biguanide) can claim its origins in the use of Galega officinalis as a plant treatment for symptoms ascribed to diabetes. Since the first clinical use of metformin as a glucose-lowering agent in 1957, this medicine has emerged as a first-line pharmacological option to support lifestyle interventions in the management of type 2 diabetes (T2D). It acts through multiple cellular pathways, principally in the gut, liver and muscle, to counter insulin resistance and lower blood glucose without weight gain or risk of overt hypoglycaemia. Other effects include improvements in lipid metabolism, decreased inflammation and lower long-term cardiovascular risk. Metformin is conveniently combined with other diabetes medications, can be prescribed in prediabetes to reduce the risk of progression to T2D, and is used in some regions to assist glycaemic control in pregnancy. Consistent with its diversity of actions, established safety profile and cost-effectiveness, metformin is being assessed for further possible clinical applications. The use of metformin requires adequate renal function for drug elimination, and may cause initial gastrointestinal side effects, which can be moderated by taking with meals or using an extended-release formulation. Thus, metformin serves as a valuable therapeutic resource for use throughout the natural history of T2D.

From Molecular Mechanisms to Clinical Therapy: Understanding Sepsis-Induced Multiple Organ Dysfunction

Sepsis-induced multiple organ dysfunction arises from the highly complex pathophysiology encompassing the interplay of inflammation, oxidative stress, endothelial dysfunction, mitochondrial damage, cellular energy failure, and dysbiosis. Over the past decades, numerous studies have been dedicated to elucidating the underlying molecular mechanisms of sepsis in order to develop effective treatments. Current research underscores liver and cardiac dysfunction, along with acute lung and kidney injuries, as predominant causes of mortality in sepsis patients. This understanding of sepsis-induced organ failure unveils potential therapeutic targets for sepsis treatment. Various novel therapeutics, including melatonin, metformin, palmitoylethanolamide (PEA), certain herbal extracts, and gut microbiota modulators, have demonstrated efficacy in different sepsis models. In recent years, the research focus has shifted from anti-inflammatory and antioxidative agents to exploring the modulation of energy metabolism and gut microbiota in sepsis. These approaches have shown a significant impact in preventing multiple organ damage and mortality in various animal sepsis models but require further clinical investigation. The accumulation of this knowledge enriches our understanding of sepsis and is anticipated to facilitate the development of effective therapeutic strategies in the future.

1-DNJ Alleviates Obesity-Induced Testicular Inflammation in Mice Model by Inhibiting IKKβ/ NF-kB Pathway

Obesity is associated with chronic inflammation that affects various organs in the body, including the reproductive system, which is a key factor in male infertility. 1-Deoxynojirimycin (1-DNJ) is a natural alkaloid in mulberry leaves, which has anti-inflammatory capabilities, yet, it's effects on obesity-induced inflammation-related male infertility remain unclear. Therefore, this research investigates the underlying mechanism by which 1-DNJ may mitigate fertility impairment in male mice caused by obesity-related inflammation. Male mice with high-fat diet (HFD)-induced obesity were treated with 1-DNJ or metformin for 8 weeks. Metabolic profiles were evaluated by enzyme method. Reproductive capacity was assessed by sperm viability, motility and counts, immunohistochemistry was performed to evaluate the testicular damage caused by obesity and inflammation. The inflammation was assessed by measuring the levels of tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), and interleukin 6 (IL-6). The activation of IκB kinase β (IKKβ) and nuclear factor κB (NF-κB) was examined using western blot and immunohistochemistry. HFD induced obesity in mice with obvious lipid metabolism disorder. The obese male mice had a decreased testosterone level, impaired sperm motility, and increased inflammatory factors. 1-DNJ treatment improved the testosterone level in the obese mice, ameliorated the testicular structure damage and improve sperm viability. In addition, 1-DNJ treatment inhibited IKKβ/NF-kB signaling pathway and reduced inflammation in obese mice. 1-DNJ can improve the fertility of obese men by reducing obesity as well as obesity-induced inflammation. These findings provide new insights for 1-DNJ to alleviate inflammation caused by obesity and provide future possibilities for treating male infertility.

Metformin exposure and the incidence of lactic acidosis in critically ill patients with T2DM: A retrospective cohort study

OBJECTIVE

The objective of this study was to investigate the correlation between metformin exposure and the incidence of lactic acidosis in critically ill patients.

METHODS

The patients with type 2 diabetes mellitus (T2DM) were included from Medical Information Mart for Intensive Care IV database (MIMIC-IV). The primary outcome was the incidence of lactic acidosis. The secondary outcomes were lactate level and in-hospital mortality. Propensity score matching (PSM) method was adopted to reduce bias of the confounders. The multivariate logistic regression was used to explore the correlation between metformin exposure and the incidence of lactic acidosis. Subgroup analysis and sensitivity analysis were used to test the stability of the conclusion.

RESULTS

We included 4939 patients. There were 2070 patients in the metformin group, and 2869 patients in the nonmetformin group. The frequency of lactic acidosis was 5.7% (118/2070) in the metformin group and it was 4.3% (122/2869) in the nonmetformin group. There was a statistically significant difference between the two groups (P < 0.05). The lactate level in the metformin group was higher than in the nonmetformin group (2.78 ± 2.23 vs. 2.45 ± 2.24, P < 0.001). After PSM, the frequency of lactic acidosis (6.3% vs. 3.7%, P < 0.001) and lactate level (2.85 ± 2.38 vs. 2.40 ± 2.14, P < 0.001) were significantly higher in the metformin group compared with the nonmetformin group. In multivariate logistic models, the frequency of lactic acidosis was obviously increased in metformin group, and the adjusted odds ratio (OR) of metformin exposure was 1.852 (95% confidence interval (CI) = 1.298-2.643, P < 0.001). The results were consistent with subgroup analysis except for respiratory failure subgroup. Metformin exposure increased lactate level but did not affect the frequency of lactic acidosis in patients of respiratory failure with hypercapnia. However, the in-hospital mortality between metformin and nonmetformin group had no obvious difference (P = 0.215). In sensitivity analysis, metformin exposure showed similar effect as the original cohort.

CONCLUSIONS

In critically ill patients with T2DM, metformin exposure elevated the incidence of lactic acidosis except for patients of respiratory failure with hypercapnia, but did not affect the in-hospital mortality.

A sono-responsive antibacterial nanosystem co-loaded with metformin and bone morphogenetic protein-2 for mitigation of inflammation and bone loss in experimental peri-implantitis

Background

Dental implants have become an increasingly popular option for replacing missing teeth, and the prevalence of peri-implantitis has also increased, which is expected to become a public health problem worldwide and cause high economic and health burdens. This scenario highlights the need for new therapeutic options to treat peri-implantitis.

Methods

In this study, we proposed a novel sono-responsive antibacterial nanosystem co-loaded with metformin (Met) and bone morphogenetic protein-2 (BMP-2) to promote efficacy in treating peri-implantitis. We introduced the zeolitic imidazolate framework-8 (ZIF-8) as a carrier for hematoporphyrin monomethyl ether (HMME) to enhance the antibacterial effect of sonodynamic antibacterial therapy and tested its reactive oxygen species (ROS) production efficiency and bactericidal effect in vitro. Afterward, HMME-loaded ZIF-8, BMP-2-loaded polylactic acid-glycolic acid (PLGA), and Met were incorporated into gelatin methacryloyl (GelMA) hydrogels to form HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels, and the biocompatibility of which was determined in vitro and in vivo. A bacterial-induced peri-implantitis model in the maxilla of rats was established to detect the effects of the composite hydrogels with adjunctive use of ultrasound on regulating inflammation and promoting bone tissue repair in vivo.

Results

The results indicated that HMME@ZIF-8 with ultrasound stimulation demonstrated more better ROS production efficiency and antimicrobial efficacy. The composite hydrogels had good biocompatibility. Ultrasound-assisted application of the composite hydrogels reduced the release of the inflammatory factors IL-6 and TNF-α and reduced bone loss around the implant in rats with bacterial-induced peri-implantitis.

Conclusion

Our observations suggest that HMME@ZIF-8 may be a new good sonosensitizer material for sonodynamic antibacterial therapy. The use of HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels in combination with ultrasound can provide a novel option for treating peri-implantitis in the future.

Adenosine 5'monophosphate-activated protein kinase activation reduces the risks of psoriasis and its comorbidities: a Mendelian randomization study in the UK Biobank

OBJECTIVE

Whether metformin and its adenosine 5'monophosphate-activated protein kinase (AMPK) activation protect from psoriasis risk is unconcluded. We investigated the effect of AMPK, a pharmacological target of metformin, on the risk of psoriasis and its comorbidities and mortality among participants in the UK Biobank (UKB).

METHODS

To avoid immortal time biases in pharmacoepidemiologic studies, Mendelian randomization was used to infer the AMPK pathway-dependent effects. The cut-off age for distinguishing early-onset/late-onset psoriasis (EOP/LOP) was set at 60 years, based on the incident psoriasis peak in UKB. A genetic instrument comprising 44 single-nucleotide polymorphisms associated with glycated haemoglobin (HbA1c), serving as a proxy for AMPK genetic risk score (negatively associated with AMPK activation), was employed as previously reported in the literature. Log-binomial models were used to estimate the effect size of AMPK regarding relative risk (RR) and 95% CI.

RESULTS

A total of 407 159 participants were analysed, including 9126 EOP and 3324 LOP. The AMPK genetic risk score was associated with a 12.4% increase in the risk of LOP in men (RR = 1.124, 95% CI: 1.022-1.236). This association was not significant for EOP or women. AMPK genetic risk score exhibited an elevated risk of ischemic heart disease (RR = 1.217, 95% CI 1.062-1.395) in male psoriasis patients.

CONCLUSIONS

AMPK activation may protect against LOPs and associated ischemic heart disease in men. A sex-specific, comorbidity-targeted intervention for psoriasis is needed.

Effect of metformin and lifestyle intervention on adipokines and hormones in breast cancer survivors: a pooled analysis from two randomized controlled trials

PURPOSE

We investigated the effect of metformin and lifestyle intervention on metabolic, inflammatory, and steroid biomarkers of breast cancer (BC) recurrence risk in two intervention trials among BC survivors with overweight or obesity.

METHODS

Baseline and follow-up serum samples collected during the two trials were analyzed and data pooled. The USA trial (Reach for Health) included postmenopausal BC survivors (n = 333) randomly assigned to 6-month metformin vs placebo and lifestyle intervention (LSI) vs control (2 × 2 factorial design). The Italian trial (MetBreCS) included BC survivors (n = 40) randomized to 12-month metformin vs placebo. Insulin resistance (HOMA-IR), adipokines, cytokines, and steroids were measured.

RESULTS

Metformin compared to placebo showed a favorable decrease in leptin (- 8.8 vs - 3.5 ng/mL; p < 0.01) and HOMA-IR (- 0.48 vs - 0.25; p = 0.03), and an increase in SHBG (2.80 vs 1.45 nmol/L; p < 0.01). Excluding women taking aromatase inhibitors, metformin (n = 84) compared to placebo (n = 99) decreased estradiol (- 4 vs 0 pmol/L; p < 0.01), estrone (- 8 vs 2 pmol/L; p < 0.01) and testosterone (- 0.1 vs 0 nmol/L-; p = 0.02). LSI favorably affected adiponectin (0.45 vs - 0.06 ug/mL; p < 0.01), leptin (- 10.5 vs - 4.4 ng/mL; p < 0.01), HOMA-IR (- 0.6 vs 0.2; p = 0.03), and SHBG (2.7 vs 1.1 nMol/L; p = 0.04) compared to controls. The strongest impact was observed combining metformin with LSI on adipokines, CRP, SHBG, and estrogens.

CONCLUSIONS

Supportive healthy lifestyle programs combined with metformin to achieve maximal risk reduction among BC cancer survivors are recommended, especially for those with obesity in menopause.

The Contribution of Type 2 Diabetes to Parkinson's Disease Aetiology

Type 2 diabetes (T2D) and Parkinson's disease (PD) are chronic disorders that have a significant health impact on a global scale. Epidemiological, preclinical, and clinical research underpins the assumption that insulin resistance and chronic inflammation contribute to the overlapping aetiologies of T2D and PD. This narrative review summarises the recent evidence on the contribution of T2D to the initiation and progression of PD brain pathology. It also briefly discusses the rationale and potential of alternative pharmacological interventions for PD treatment.

Efficacy of metformin and electrical pulses in breast cancer MDA-MB-231 cells

Aim

Triple-negative breast cancer (TNBC) is a very aggressive subset of breast cancer, with limited treatment options, due to the lack of three commonly targeted receptors, which merits the need for novel treatments for TNBC. Towards this need, the use of metformin (Met), the most widely used type-2 diabetes drug worldwide, was explored as a repurposed anticancer agent. Cancer being a metabolic disease, the modulation of two crucial metabolites, glucose, and reactive oxygen species (ROS), is studied in MDA-MB-231 TNBC cells, using Met in the presence of electrical pulses (EP) to enhance the drug efficacy.

Methods

MDA-MB-231, human TNBC cells were treated with Met in the presence of EP, with various concentrations Met of 1 mmol/L, 2.5 mmol/L, 5 mmol/L, and 10 mmol/L. EP of 500 V/cm, 800 V/cm, and 1,000 V/cm (with a pulse width of 100 µs at 1 s intervals) were applied to TNBC and the impact of these two treatments was studied. Various assays, including cell viability, microscopic inspection, glucose, ROS, and wound healing assay, were performed to characterize the response of the cells to the combination treatment.

Results

Combining 1,000 V/cm with 5 mmol/L Met yielded cell viability as low as 42.6% at 24 h. The glucose level was reduced by 5.60-fold and the ROS levels were increased by 9.56-fold compared to the control, leading to apoptotic cell death.

Conclusions

The results indicate the enhanced anticancer effect of Met in the presence of electric pulses. The cell growth is inhibited by suppressing glucose levels and elevated ROS. This shows a synergistic interplay between electroporation, Met, glucose, and ROS metabolic alterations. The results show promises for combinational therapy in TNBC patients.

Therapeutic effects of anti-diabetic drugs on traumatic brain injury

AIMS

In this narrative review, we have analyzed and synthesized current studies relating to the effects of anti-diabetic drugs on traumatic brain injury (TBI) complications.

METHODS

Eligible studies were collected from Scopus, Google Scholar, PubMed, and Cochrane Library for clinical, in-vivo, and in-vitro studies published on the impact of anti-diabetic drugs on TBI.

RESULTS

Traumatic brain injury (TBI) is a serious brain disease that is caused by any type of trauma. The pathophysiology of TBI is not yet fully understood, though physical injury and inflammatory events have been implicated in TBI progression. Several signaling pathways are known to play pivotal roles in TBI injuries, including Nuclear factor erythroid 2-related factor 2 (Nrf2), High mobility group box 1 protein/Nuclear factor kappa B (HMGB1/NF-κB), Adiponectin, Mammalian Target of Rapamycin (mTOR), Toll-Like Receptor (TLR), Wnt/β-catenin, Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT), Nod-like receptor protein3 (NLRP3) inflammasome, Phosphoglycerate kinase 1/Kelch-like ECH-associated protein 1 (PGK1/KEAP1)/Nrf2, and Mitogen-activated protein kinase (MAPK) . Recent studies suggest that oral anti-diabetic drugs such as biguanides, thiazolidinediones (TZDs), sulfonylureas (SUs), sodium-glucose cotransporter-2 inhibitors (SGLT2is), dipeptidyl peptidase-4 inhibitors (DPPIs), meglitinides, and alpha-glucosidase inhibitors (AGIs) could have beneficial effects in the management of TBI complications. These drugs may downregulate the inflammatory pathways and induce antioxidant signaling pathways, thus alleviating complications of TBI.

CONCLUSION

Based on this comprehensive literature review, antidiabetic medications might be considered in the TBI treatment protocol. However, evidence from clinical trials in patients with TBI is still warranted.

Examining the clinical relevance of metformin as an antioxidant intervention

In physiological concentrations, reactive oxygen species play a vital role in regulating cell signaling and gene expression. Nevertheless, oxidative stress is implicated in the pathogenesis of numerous diseases and can inflict damage on diverse cell types and tissues. Thus, understanding the factors that mitigate the deleterious effects of oxidative stress is imperative for identifying new therapeutic targets. In light of the absence of direct treatment recommendations for reducing oxidative stress, there is a continuing need for fundamental research that utilizes innovative therapeutic approaches. Metformin, known for its multifaceted beneficial properties, is acknowledged for its ability to counteract the adverse effects of increased oxidative stress at both molecular and cellular levels. In this review, we delve into recent insights regarding metformin's antioxidant attributes, aiming to expand its clinical applicability. Our review proposes that metformin holds promise as a potential adjunctive therapy for various diseases, given its modulation of oxidative stress characteristics and regulation of diverse metabolic pathways. These pathways include lipid metabolism, hormone synthesis, and immunological responses, all of which may experience dysregulation in disease states, contributing to increased oxidative stress. Furthermore, our review introduces potential novel metformin-based interventions that may merit consideration in future research. Nevertheless, the necessity for clinical trials involving this drug remains imperative, as they are essential for establishing therapeutic dosages and addressing challenges associated with dose-dependent effects.

Bibliometrics and visual analysis of metformin and gut microbiota from 2012 to 2022: A systematic review

BACKGROUND

Metformin is an old drug used for the treatment of type 2 diabetes mellitus and can play a variety of roles by regulating the gut microbiota. The number of research articles on metformin in the gut microbiota has increased annually; however, no bibliometric tools have been used to analyze the research status and hot trends in this field. This study presents a bibliometric analysis of publications on metformin and gut microbiota.

METHODS

We searched the Web of Science core collection database on June 8, 2023, for papers related to metformin and gut microbiota from 2012 to 2022. We used Microsoft Excel 2021, VOSviewer1.6.19, CiteSpace 6.2.4, and R software package "bibliometrix" 4.0.0 to analyze the countries, institutions, authors, journals, citations, and keywords of the included publications.

RESULTS

We included 517 papers, and the trend in publications increased over the last 11 years. The 517 articles were from 57 countries, including 991 institutions and 3316 authors, and were published in 259 journals. China led all countries (233 papers) and the most influential institution was the Chinese Academy of Sciences (16 papers). PLOS ONE (19 papers) was the most popular journal, and Nature (1598 citations) was the most cited journal. Li and Kim were the 2 most published authors (six papers each), and Cani (272 co-citations) was the most co-cited author. "Metabolites," "aging," and "intestinal barrier" were emerging topics in this field.

CONCLUSIONS

This bibliometric study comprehensively summarizes the research trends and progress of metformin and gut microbiota, and provides new research topics and trends for studying the effects of metformin on gut microbiota in different diseases.

IL-6 Trans-Signaling Is Increased in Diabetes, Impacted by Glucolipotoxicity, and Associated With Liver Stiffness and Fibrosis in Fatty Liver Disease

Many people living with diabetes also have nonalcoholic fatty liver disease (NAFLD). Interleukin-6 (IL-6) is involved in both diseases, interacting with both membrane-bound (classical) and circulating (trans-signaling) soluble receptors. We investigated whether secretion of IL-6 trans-signaling coreceptors are altered in NAFLD by diabetes and whether this might associate with the severity of fatty liver disease. Secretion patterns were investigated with use of human hepatocyte, stellate, and monocyte cell lines. Associations with liver pathology were investigated in two patient cohorts: 1) biopsy-confirmed steatohepatitis and 2) class 3 obesity. We found that exposure of stellate cells to high glucose and palmitate increased IL-6 and soluble gp130 (sgp130) secretion. In line with this, plasma sgp130 in both patient cohorts positively correlated with HbA1c, and subjects with diabetes had higher circulating levels of IL-6 and trans-signaling coreceptors. Plasma sgp130 strongly correlated with liver stiffness and was significantly increased in subjects with F4 fibrosis stage. Monocyte activation was associated with reduced sIL-6R secretion. These data suggest that hyperglycemia and hyperlipidemia can directly impact IL-6 trans-signaling and that this may be linked to enhanced severity of NAFLD in patients with concomitant diabetes.

ARTICLE HIGHLIGHTS

IL-6 and its circulating coreceptor sgp130 are increased in people with fatty liver disease and steatohepatitis. High glucose and lipids stimulated IL-6 and sgp130 secretion from hepatic stellate cells. sgp130 levels correlated with HbA1c, and diabetes concurrent with steatohepatitis further increased circulating levels of all IL-6 trans-signaling mediators. Circulating sgp130 positively correlated with liver stiffness and hepatic fibrosis. Metabolic stress to liver associated with fatty liver disease might shift the balance of IL-6 classical versus trans-signaling, promoting liver fibrosis that is accelerated by diabetes.

The Role and Mechanism of Metformin in Inflammatory Diseases

Metformin is a classical drug used to treat type 2 diabetes. With the development of research on metformin, it has been found that metformin also has several advantages aside from its hypoglycemic effect, such as anti-inflammatory, anti-aging, anti-cancer, improving intestinal flora, and other effects. The prevention of inflammation is critical because chronic inflammation is associated with numerous diseases of considerable public health. Therefore, there has been growing interest in the role of metformin in treating various inflammatory conditions. However, the precise anti-inflammatory mechanisms of metformin were inconsistent in the reported studies. Thus, this review aims to summarize various currently known possible mechanisms of metformin involved in inflammatory diseases and provide references for the clinical application of metformin.

Metformin has anti-inflammatory effects and induces immunometabolic reprogramming via multiple mechanisms in hidradenitis suppurativa

BACKGROUND

Targeting immunometabolism has shown promise in treating autoimmune and inflammatory conditions. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease involving painful lesions in apocrine gland-bearing skin. Therapeutic options for HS are limited and often ineffective; thus, there is a pressing need for improved treatments. To date, metabolic dysregulation has not been investigated in HS. As HS is highly inflammatory, we hypothesized that energy metabolism is dysregulated in these patients. Metformin, an antidiabetic drug, which is known to impact on cellular metabolic and signalling pathways, has been shown to have anti-inflammatory effects in cancer and arthritis. While metformin is not licensed for use in HS, patients with HS taking metformin show improved clinical symptoms.

OBJECTIVE

To assess the effect and mechanism of action of metformin in HS.

METHODS

To assess the effect of metformin in vivo, we compared the immune and metabolic profiles of peripheral blood mononuclear cells (PBMCs) of patients with HS taking metformin vs. those not taking metformin. To examine the effect of metformin treatment ex vivo, we employed a skin explant model on skin biopsies from patients with HS not taking metformin, which we cultured with metformin overnight. We used enzyme-linked immunosorbent assays, multiplex cytokine assays and quantitative real-time polymerase chain reaction (RT-PCR) to measure inflammatory markers, and Seahorse flux technology and quantitative RT-PCR to assess glucose metabolism.

RESULTS

We showed that metabolic pathways are dysregulated in the PBMCs of patients with HS vs. healthy individuals. In metformin-treated patients, these metabolic pathways were restored and their PBMCs had reduced inflammatory markers following long-term metformin treatment. In the skin explant model, we found that overnight culture with metformin reduced inflammatory cytokines and chemokines and glycolytic genes in lesions and tracts of patients with HS. Using in vitro assays, we found that metformin may induce these changes via the NLR family pyrin domain containing 3 (NLRP3) inflammasome and the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway, which is linked to glycolysis and protein synthesis.

CONCLUSIONS

Our study provides insight into the mechanisms of action of metformin in HS. The anti-inflammatory effects of metformin support its use as a therapeutic agent in HS, while its effects on immunometabolism suggest that targeting metabolism is a promising therapeutic option in inflammatory diseases, including HS.

Effects of metformin therapy on HMGB1 levels in rheumatoid arthritis patients

OBJECTIVE

The traditional treatment of rheumatoid arthritis (RA) has some side effects. We aimed to explore the effect of metformin treatment on the expression of HMGB1, cytokines, T cell subtypes and the clinical outcomes in RA patients.

METHODS

The present prospective cohort study recruited 124 RA patients (metformin group) who were treated with metformin and conventional therapy (methotrexate, hydroxychloroquine sulfate and sulfasalazine) and 98 RA patients (conventional therapy group) who were only treated with conventional therapy. All subjects were admitted from December 2018 to December 2021 and continuous medication for 90 days. The serum high mobility group box 1 (HMGB1), tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-1β and C-reactive protein (CRP) levels were measured by enzyme-linked immunosorbent assay (ELISA). Flow cytometric were used to analyze the expression of CD4+ and CD8+. Demographic and clinical statistics including age, body mass index (BMI), sex, course of disease, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), visual analogue score (VAS)and disease activity score (DAS)-28 were collected.

RESULTS

The serum levels of HMGB1, CRP, IL-6, CD4+ expression and CD4+/CD8+ ratio were significantly increased in patients with DAS-28 score ≥ 2.6. The serum HMGB1 and cytokines levels of metformin group declined more quickly during the study time. Pearson's analysis supported that a positive correlation existed between the HMGB1 and IL-6, TNF-α, CRP, CD4+, CD4+/CD8+ ratio, and VAS scores. HMGB1 could be a potential diagnostic biomarker for RA patients in active phase. Serum HMGB1 (95% CI 1.133-1.397, P < 0.001) was a factor associated with active RA.

CONCLUSION

The serum HMGB1 levels were significantly increased in RA patients in active phase. The serum levels of HMGB1 and inflammatory factors and VAS scores were decreased gradually with metformin treatment. HMGB1 might act as a novel therapeutic target for RA.

Protective effect of heat-processed Gynostemma pentaphyllum on high fat diet-induced glucose metabolic disorders mice

Glucose metabolic disorders (GMD) can promote insulin resistance (IR) and diabetes, and damage liver and kidney. Gynostemma pentaphyllum is commonly used in the clinical treatment of diabetes, but the research on its main active constituents and GMD has not been reported yet. This study explores the therapeutic potential of gypenosides of heat-processed Gynostemma pentaphyllum (HGyp) on high-fat diet-induced GMD in mice. HGyp was administered at different doses for 12 weeks. The investigation encompassed an array of parameters, including body weight, blood lipids, blood glucose, and liver tissue components. Metabolomic and network analyses were conducted to uncover potential targets and pathways associated with HGyp treatment. The results revealed that HGyp alleviated GMD by reducing body weight, blood glucose, and improving blood lipids levels, while increasing liver glycogen and antioxidant enzyme levels. Additionally, HGyp exhibited protective effects on liver and kidney health by reducing tissue damage. Fourteen blood components were detected by LC-MS. Metabolomic and network analyses indicated the potential engagement of the AGE-RAGE signaling pathway in the therapeutic effects of HGyp.Furthermore, Western blot and ELISA assays confirmed that HGyp upregulated GLO1 and GLUT4 while down-regulating AGEs and RAGE expression in liver tissue. In light of these findings, HGyp demonstrates promise as a potential therapeutic candidate for combating GMD, warranting further exploration in the development of therapeutic strategies or functional products.

Investigating the impact of metformin on severity of COVID-19 in patients with Type 2 diabetes mellitus: Focusing on laboratory findings

BACKGROUND

In the terrifying pandemic caused by SARS-CoV-2, diabetic patients exhibiting more severe outcomes and mortality rate is high among them. Based on recent studies, metformin as the most prescribed drug for T2DM treatment may improve severe outcomes in diabetic patients infected with SARS-CoV-2. On the other hand, abnormal laboratory findings can help to differentiate between the severe and non-severe form of COVID-19. According to the mentioned issues, the effect of metformin on severity of COVID-19 was examined in T2DM patients with SARS-CoV-2 infection.

METHODS

The study included 187 individuals diagnosed with COVID-19, 104 patients were diabetic and divided into two groups according to their anti-diabetic drugs: patients who were treated only with metformin and patients who were treated with other anti-diabetic drugs. The other participants were non-diabetic and diagnosed with COVID-19. Biochemical parameters were measured by routine laboratory methods before, during and after SARS-CoV-2 infection.

RESULTS

During infection, FBS, creatinine, ALT, AST, Ferritin and LDH were significantly lower in metformin users than non-users (p-value: .02, .01, .03, .04, .0009 and .01, respectively). Also, after recovery, there were statistically significant differences between metformin users and non-users with respect to most of the study parameters, except FBS, BUN and ALP (p-value: .51, .28 and .35, respectively).

CONCLUSION

Our result suggested that metformin might be associated with better outcomes in diabetic patients infected with SARS-CoV-2.

Metformin Reduces Bone Resorption in Apical Periodontitis Through Regulation of Osteoblast and Osteoclast Differentiation

INTRODUCTION

We have previously demonstrated that auxiliary metformin therapy promotes healing of apical periodontitis. Here we aimed to investigate the effects of metformin on osteoblast differentiation and osteoclast formation in cultured cells and rat apical periodontitis.

METHODS

Murine pre-osteoblasts MC3T3-E1 and macrophages RAW264.7 were cultured under hypoxia (2% oxygen) or normoxia (21% oxygen) and stimulated with receptor activator of nuclear factor-κB ligand (RANKL) when indicated. Metformin was added to the cultures to evaluate its anti-hypoxic effects. Expressions of osteoblast differentiation regulator runt-related transcription factor 2 (RUNX2), RANKL, and osteoclast marker tartrate-resistant acid phosphatase (TRAP) were assessed by Western blot. Apical periodontitis was induced in mandibular first molars of 10 Sprague-Dawley rats. Root canal therapy with or without metformin supplement was performed. Periapical bone resorption was measured by micro-computed tomography. Immunohistochemistry was used to examine RUNX2, RANKL, and TRAP expressions.

RESULTS

Hypoxia suppressed RUNX2 expression and enhanced RANKL synthesis in pre-osteoblasts. TRAP production increased in macrophages after hypoxia and/or RANKL stimulation. Metformin reversed hypoxia-induced RUNX2 suppression and RANKL synthesis in pre-osteoblasts. Metformin also inhibited hypoxia and RANKL-enhanced TRAP synthesis in macrophages. Intracanal metformin diminished bone loss in rat apical periodontitis. Comparing with vehicle control, cells lining bone surfaces in metformin-treated lesions had significantly stronger expression of RUNX2 and decreased synthesis of RANKL and TRAP.

CONCLUSIONS

Alleviation of bone resorption by intracanal metformin was associated with enhanced osteoblast differentiation and diminished osteoclast formation in rat apical periodontitis. Our results endorsed the role of metformin as an effective medicament for inflammatory bone diseases.

Non-clinical pharmacokinetics study in rat plasma, tissues and excreta of honokiol derivative HM475 by UPLC-Q-TOF-MS/MS

To provide the basis for further development and research of drugs, non-clinical pharmacokinetics studies were conducted on HM475, which is composed of natural active molecules honokiol and metformin through cyclization. In this paper, HM475 was studied from six aspects by gavage and intraperitoneal injection: 1) Acute toxicity of HM475 in rats, 2) Pharmacokinetic characteristics of HM475 in rats, 3) Distribution characteristics of HM475 in heart, liver, spleen, lung, and kidney, small intestine, fat and brain of rats, 4) Main metabolic pathways of HM475 in rats, 5) Excretion of HM475 in rats, 6) Determination of protein binding rate of HM475 in bovine plasma, rabbit plasma, and rat plasma. Acute toxicity of HM475 on SD rats was evaluated by maximum dose method. The metabolic analysis method of HM475 in rats was first established by UPLC-Q-TOF-MS/MS technology, and the pharmacokinetic characteristics of oral administration and intraperitoneal injection were studied. Experimental results showed that HM475 had no obvious acute toxicity. The absolute oral bioavailability of HM475 was 38.45 %, and the drug concentration in plasma was higher than that in tissues. Combined with the process characteristics of HM475 in vivo, it is inferred that HM475 has enterohepatic circulation. In this study, non-clinical pharmacokinetics were systematically studied to provide data support for the clinical pharmacokinetics and pharmacodynamics of HM475, to more accurately predict the pharmacokinetic behavior of HM475 in human body and provide scientific data for the compound to enter clinical research.

Effect of Metformin on the Functional and Electrophysiological Recovery of Crush Injury-Induced Facial Nerve Paralysis in Diabetic Rats

The impact of metformin on the rat facial nerve following crush injury has only occasionally been documented to date. The purpose of the current investigation was to use functional and electrophysiological evaluations to investigate the effects of metformin administration on recovery following crush injury to the rat facial nerve. The rats were randomly divided into four groups: the nonDM/PBS group (n = 4), the nonDM/metformin group (n = 4), the DM/PBS group (n = 4), and the DM/metformin group (n = 4). Diabetes was generated by an intraperitoneal injection of streptozotocin. Facial nerve paralysis was induced by a crush injury 7 days after diabetes induction. The blood glucose levels of the DM/PBS and DM/metformin groups were maintained at over 300 mg/dL, whereas the blood glucose levels of the nonDM/PBS and nonDM/metformin groups were maintained at less than 150 mg/dL. There was no significant difference between the two nonDM groups. In comparison to the PBS group, the metformin group's recurrence of vibrissa fibrillation occurred noticeably sooner over time. The nonDM/metformin group showed the highest recovery rate in the second, third, and fourth weeks post-crush, respectively. The threshold of action potential 4 weeks after crush injury showed that the nonDM/metformin group had a significantly lower mean threshold of MAP compared to other groups. The short-term effect of metformin on the recovery of facial nerve blood flow (FNBF) was significantly increased compared to the DM/PBS group. However, there was no significant difference in FNBF between the nonDM/metformin and nonDM/PBS groups. A diabetic condition promoted a delay in FN regeneration. Metformin is able to accelerate functional recovery in diabetic or nondiabetic FN-injured rats. Further studies using a morphometric or molecular approach are planned to understand the pharmacologic mechanism of metformin.

Metformin Prevents NDEA-Induced Memory Impairments Associated with Attenuating Beta-Amyloid, Tumor Necrosis Factor-Alpha, and Interleukin-6 Levels in the Hippocampus of Rats

N-nitrosodiethylamine (NDEA) is a potential carcinogen known to cause liver tumors and chronic inflammation, diabetes, cognitive problems, and signs like Alzheimer's disease (AD) in animals. This compound is classified as probably carcinogenic to humans. Usual sources of exposure include food, beer, tobacco, personal care products, water, and medications. AD is characterized by cognitive decline, amyloid-β (Aβ) deposit, tau hyperphosphorylation, and cell loss. This is accompanied by neuroinflammation, which involves release of microglial cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin 1β (IL-1β), by nuclear factor kappa B (NF-κB) upregulation; each are linked to AD progression. Weak PI3K/Akt insulin-signaling inhibits IRS-1 phosphorylation, activates GSK3β and promotes tau hyperphosphorylation. Metformin, an antihyperglycemic agent, has potent anti-inflammatory efficacy. It reduces proinflammatory cytokines such as IL-6, IL-1β, and TNF-α via NF-κB inhibition. Metformin also reduces reactive oxidative species (ROS) and modulates cognitive disorders reported due to brain insulin resistance links. Our study examined how NDEA affects spatial memory in Wistar rats. We found that all NDEA doses tested impaired memory. The 80 µg/kg dose of NDEA increased levels of Aβ1-42, TNF-α, and IL-6 in the hippocampus, which correlated with memory loss. Nonetheless, treatment with 100 mg/kg of metformin attenuated the levels of pro-inflammatory cytokines and Aβ1-42, and enhanced memory. It suggests that metformin may protect against NDEA-triggered memory issues and brain inflammation.

Type 2 Diabetes Mellitus, Non-Alcoholic Fatty Liver Disease, and Metabolic Repercussions: The Vicious Cycle and Its Interplay with Inflammation

The prevalence of metabolic-related disorders, such as non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (DM2), has been increasing. Therefore, developing improved methods for the prevention, treatment, and detection of these two conditions is also necessary. In this study, our primary focus was on examining the role of chronic inflammation as a potential link in the pathogenesis of these diseases and their interconnections. A comprehensive search of the PubMed database using keywords such as "non-alcoholic fatty liver disease", "type 2 diabetes mellitus", "chronic inflammation", "pathogenesis", and "progression" yielded 177 relevant papers for our analysis. The findings of our study revealed intricate relationships between the pathogenesis of NAFLD and DM2, emphasizing the crucial role of inflammatory processes. These connections involve various molecular functions, including altered signaling pathways, patterns of gene methylation, the expression of related peptides, and up- and downregulation of several genes. Our study is a foundational platform for future research into the intricate relationship between NAFLD and DM2, allowing for a better understanding of the underlying mechanisms and the potential for introducing new treatment standards.

Metformin Treatment of Hidradenitis Suppurativa: Effect on Metabolic Parameters, Inflammation, Cardiovascular Risk Biomarkers, and Immune Mediators

Hidradenitis suppurativa (HS) is a common cutaneous and systemic inflammatory disease with a significant impact on mental health and quality of life. It is associated with obesity, insulin resistance, metabolic syndrome, cardiovascular (CV) disease, and increased all-cause mortality. Metformin is used frequently in HS treatment and is effective for some patients. The mechanism of action of metformin in HS is unknown. A case-control study of 40 patients with HS (20 on metformin and 20 controls) was conducted to assess differences in metabolic markers, inflammation (C-reactive protein [CRP], serum adipokines, and CV risk biomarkers), and serum immune mediators. Body mass index (BMI), insulin resistance (77%), and metabolic syndrome (44%) were high overall, but not significantly different between the groups. This highlights the need for co-morbidity screening and management. A significant reduction in fasting insulin and a trend towards a reduction in insulin resistance were identified in the metformin group compared with pre-treatment levels. CV risk biomarkers were significantly favourable in the metformin group (lymphocytes, monocyte-lymphocyte ratio, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio). CRP was lower in the metformin group but was not statistically significant. Adipokines were dysregulated overall but were not different between the two groups. Serum IFN-γ, IL-8, TNF-α, and CXCL1 trended lower in the metformin group but did not reach significance. These results suggest that metformin improves CV risk biomarkers and insulin resistance in patients with HS. When the results of this study are considered alongside other studies in HS and related conditions, it is likely that metformin also has beneficial effects on metabolic markers and systemic inflammation in HS (CRP, serum adipokines, and immune mediators), warranting further research.

Insight on Infections in Diabetic Setting

The correlation between diabetes mellitus and infectious diseases is widely recognized. DM patients are characterized by the impaired function of the immune system. This translates into the occurrence of a variety of infections, including urinary tract, skin and surgical site infections, pneumonia, tuberculosis, and, more recently, SARS-CoV-2. Hyperglycemia has been identified as a relevant factor contributing to unfavorable outcomes in hospitalized patients including SARS-CoV-2 patients. Several studies have been performed proving that to maintain the proper and stringent monitoring of glycemia, a balanced diet and physical activity is mandatory to reduce the risk of infections and their associated complications. This review is focused on the mechanisms accounting for the increased susceptibility of DM patients to infections, with particular attention to the impact of newly introduced hypoglycemic drugs in sepsis management.

Mechanisms and efficacy of metformin-mediated suppression of established experimental abdominal aortic aneurysms

Objective

Metformin treatment attenuates experimental abdominal aortic aneurysm (AAA) formation, as well as reduces clinical AAA diameter enlargement in patients with diabetes. The mechanisms of metformin-mediated aneurysm suppression, and its efficacy in suppressing established experimental aneurysms, remain uncertain.

Methods

Experimental AAAs were created in male C57BL/6J mice via intra-aortic infusion of porcine pancreatic elastase. Metformin alone (250 mg/kg), or metformin combined with the 5' AMP-activated protein kinase (AMPK) antagonist Compound C (10 mg/kg), were administered to respective mouse cohorts daily beginning 4 days following AAA induction. Further AAA cohorts received either the AMPK agonist AICA riboside (500 mg/kg) as positive, or vehicle (saline) as negative, controls. AAA progression in all groups was assessed via serial in vivo ultrasonography and histopathology at sacrifice. Cytokine-producing T cells and myeloid cellularity were determined by flow cytometric analyses.

Results

Metformin limited established experimental AAA progression at 3 (-85%) and 10 (-68%) days following treatment initiation compared with saline control. Concurrent Compound C treatment reduced this effect by approximately 50%. In metformin-treated mice, reduced AAA progression was associated with relative elastin preservation, smooth muscle cell preservation, and reduced mural leukocyte infiltration and neoangiogenesis compared with vehicle control group. Metformin also resulted in reduced interferon-γ-, but not interleukin-10 or -17, producing splenic T cells in aneurysmal mice. Additionally, metformin therapy increased circulating and splenic inflammatory monocytes (CD11b⁺Ly-6C^high), but not neutrophils (CD11b⁺Ly-6G⁺), with no effect on respective bone marrow cell populations.

Conclusions

Metformin treatment suppresses existing experimental AAA progression in part via AMPK agonist activity, limiting interferon-γ-producing T cell differentiation while enhancing circulating and splenic inflammatory monocyte retention.

Association between Systemic Immunity-Inflammation Index and Hyperlipidemia: A Population-Based Study from the NHANES (2015-2020)

The systemic immunity-inflammation index (SII) is a novel inflammatory marker, and aberrant blood lipid levels are linked to inflammation. This study aimed to look at the probable link between SII and hyperlipidemia. The current cross-sectional investigation was carried out among people with complete SII and hyperlipidemia data from the 2015-2020 National Health and Nutrition Examination Survey (NHANES). SII was computed by dividing the platelet count × the neutrophil count/the lymphocyte count. The National Cholesterol Education Program standards were used to define hyperlipidemia. The nonlinear association between SII and hyperlipidemia was described using fitted smoothing curves and threshold effect analyses. A total of 6117 US adults were included in our study. A substantial positive correlation between SII and hyperlipidemia was found [1.03 (1.01, 1.05)] in a multivariate linear regression analysis. Age, sex, body mass index, smoking status, hypertension, and diabetes were not significantly correlated with this positive connection, according to subgroup analysis and interaction testing (p for interaction > 0.05). Additionally, we discovered a non-linear association between SII and hyperlipidemia with an inflection point of 479.15 using a two-segment linear regression model. Our findings suggest a significant association between SII levels and hyperlipidemia. More large-scale prospective studies are needed to investigate the role of SII in hyperlipidemia.

Inflammaging as a target for healthy ageing

Life expectancy has been on the rise for the past few decades, but healthy life expectancy has not kept pace, leading to a global burden of age-associated disorders. Advancing age is accompanied by a chronic increase in basal systemic inflammation, termed inflammaging, contributing towards an increased risk of developing chronic diseases in old age. This article reviews the recent literature to formulate hypotheses regarding how age-associated inflammaging plays a crucial role in driving chronic diseases and ill health in older adults. Here, we discuss how non-pharmacological intervention strategies (diet, nutraceutical supplements, phytochemicals, physical activity, microbiome-based therapies) targeting inflammaging restore health in older adults. We also consider alternative existing pharmacological interventions (Caloric restriction mimetics, p38 mitogen-activated protein kinase inhibitors) and explore novel targets (senolytics) aimed at combating inflammaging and optimising the ageing process to increase healthy lifespan.

Associations of levels of peripheral blood leukocyte and subtypes with type 2 diabetes: A longitudinal study of Chinese government employees

OBJECTIVES

Available evidence suggests that type 2 diabetes (T2D) may be associated with inflammation and that leukocytes are a topical clinical, biological indicator of inflammation. This study investigates the associations between peripheral blood leukocyte and subtypes levels with T2D.

METHODS

A total of 5,475 individuals were included in the baseline examination from January 2018 to April 2020, with incidence data updated to April 30, 2021, and follow-up to 5,362 individuals. T2D was defined according to the Chinese guidelines for preventing and treating type 2 diabetes. Physiological and biochemical indicators, including leukocyte and subtypes, were obtained from the physical examination results of the tertiary care hospitals relied on at the cohort sites. Covariates such as demographic characteristics and lifestyle were collected by questionnaire. Binary logistic regression and Cox proportional hazard models were used to explore the correlations. Receiver Operating Characteristic (ROC) curves and time-dependent ROC curves were used to estimate the predictive diagnosis of T2D across the subtype of leukocytes.

RESULTS

The mean follow-up time was 12 months, and the cumulative incidence density of T2D was 4.0/1000 person-years. Cross-sectional results at baseline showed that the levels of peripheral blood leukocyte and its subtypes were higher in the T2D group than in the non-T2D group. Total leukocyte count and subtypes levels were grouped by quintile. After adjusting for age, sex, family history of diabetes, lifestyle score, and triglyceride levels, all were compared with the lowest quintile of each group. Logistic regression model results showed that the corrected OR for those with the highest quintile level of leukocyte was 2.01 (95% CI: 1.02-3.98). The longitudinal analysis showed that the adjusted HR was 8.43 (95%CI: 1.06-66.92) for those with the highest quintile level of leukocytes at baseline after controlling for the effects of the above covariates. For those with the highest quintile level of neutrophils at baseline, the adjusted HR was 5.05 (95%CI: 1.01-25.29). The leukocyte and subtypes had predictive values for T2D.

CONCLUSION

Patients with T2D have a higher level of peripheral blood leukocyte and subtypes than those without the disease. Elevated leukocyte and neutrophil counts may link to a higher risk of T2D.

Association of Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio with Diabetic Kidney Disease in Chinese Patients with Type 2 Diabetes: A Cross-Sectional Study

Purpose

The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been extensively studied in a variety of diseases. However, research on their relationship with diabetic kidney disease (DKD) is limited. The aim of our study was to investigate the association between these two indicators and renal function in Chinese patients with type 2 diabetes and assess whether they can serve as predictors of DKD.

Methods

This cross-sectional study enrolled 655 Chinese patients with type 2 diabetes. Subjects were divided into three groups according to the urinary albumin-to-creatinine ratio (UACR). The differences in the NLR and PLR among the groups and their correlation with renal function were analyzed. Logistic regression analysis was used to analyze independent risk factors for DKD, and receiver operating characteristic (ROC) curves were used to assess the predictive values of the NLR and PLR for the disease.

Results

The NLR and PLR were significantly different among the three groups, and they increased with increasing levels of albuminuria. Pearson's correlation analysis showed that the NLR and PLR were positively correlated with the UACR but negatively correlated with the estimated glomerular filtration rate (eGFR) (p<0.001). Logistic regression analysis showed that these two indicators were independent risk factors for DKD (p<0.001). The results of ROC curve analysis suggested that the NLR (AUC=0.794; 95% CI, 0.760-0.827; p<0.001) and PLR (AUC=0.665; 95% CI, 0.623-0.706, p<0.001) had important diagnostic value for DKD.

Conclusion

The NLR and PLR were closely associated with renal function among Chinese patients with type 2 diabetes, and high NLR and PLR values may serve as predictors of DKD.

Metformin Improves Burn Wound Healing by Modulating Microenvironmental Fibroblasts and Macrophages

Metformin, a biguanide, exerts different functions through various signaling pathways. In order to investigate the function and mechanism of metformin in burn wounds, we established burn rat models, subcutaneously injected metformin to treat the wounds, and observed the morphologies and the expression of collagen I, collagen III, fibronectin, and pro-inflammatory markers. In vitro experiments were performed to investigate the effects of metformin on the proliferation, migration, and collagen I synthesis of the mouse embryonic fibroblast (NIH 3T3) cell line and on the proliferation, apoptosis, and immune response of the mouse mononuclear macrophage (RAW 264.7) cell line. Finally, we studied the regulatory effects of metformin on a co-culture of RAW 264.7/NIH 3T3 cells. We found that 100 mM of metformin reduced dermal thickness, collagen I deposition, and mRNA expression of IL1β and CCL2 in rat burn wounds. In vitro experiments revealed that metformin inhibited the proliferation of NIH 3T3 and RAW 264.7 cells. Metformin attenuated NIH 3T3 cell migration via the AMPK/mTOR pathway and attenuated collagen I synthesis through the TGFβ1/Smad3 pathway. Metformin inhibited the apoptosis of RAW 264.7 cells induced by 10 μg/mL LPS. Metformin downregulated the mRNA expression of IL1β and CCL2 in RAW 264.7 cells under 1 μg/mL LPS induction by inhibiting NF-κB p65 phosphorylation. In a RAW 264.7/NIH 3T3 co-culture, metformin attenuated collagen I synthesis in NIH 3T3 cells by inhibiting RAW 264.7 paracrine secretion of TGF-β1. This provides new evidence related to the development of metformin for potentially improving burn wound healing.

Metformin and bladder cancer: Drug repurposing as a potential tool for novel therapy: A review

Bladder cancer (BC) is a common type of cancer worldwide. Currently, the gold standard treatment is transurethral resection of bladder tumor (TUR-Bt) accompanied by intravesical Bacillus Calmette-Guérin (BCG) instillation for patients with middle-to-high-risk non-muscle-invasive bladder cancer (NMIBC). However, intravesical BCG therapy fails in almost 50% of high risk cases, leading to NMIBC persistence or early recurrence. In these patients, the gold standard remains radical cystectomy; however, it can seriously affect the patients' quality of life. Moreover, for patients with muscle-invasive bladder cancer (MIBC), the 5-year survival rate after radical cystectomy with neoadjuvant chemotherapy remains low. Recent discoveries have paved the way for a new era in BC treatment. Metformin is the most widely used oral hypoglycemic drug in clinical practice, being mostly used in the treatment of type 2 diabetes. Epidemiological studies have demonstrated that metformin exerts a potentially positive effect on reducing the incidence and mortality of cancer; therefore, a increasing number of studies have investigated the potential anticancer effects of metformin and its mechanisms of action. This review aims to summarize the evidence for the role of metformin in bladder cancer therapy, including how metformin mediates bladder cancer cell apoptosis.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques.

Research Progress on the Role of Pyroptosis in Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion injury (MIRI) results in the aggravation of myocardial injury caused by rapid recanalization of the ischemic myocardium. In the past few years, there is a growing interest in investigating the complex pathophysiological mechanism of MIRI for the identification of effective targets and drugs to alleviate MIRI. Currently, pyroptosis, a type of inflammatory programmed death, has received greater attention. It is involved in the MIRI development in combination with other mechanisms of MIRI, such as oxidative stress, calcium overload, necroptosis, and apoptosis, thereby forming an intertwined association between different pathways that affect MIRI by regulating common pathway molecules. This review describes the pyroptosis mechanism in MIRI and its relationship with other mechanisms, and also highlights non-coding RNAs and non-cardiomyocytes as regulators of cardiomyocyte pyroptosis by mediating associated pathways or proteins to participate in the initiation and development of MIRI. The research progress on novel small molecule drugs, clinical drugs, traditional Chinese medicine, etc. for regulating pyroptosis can play a crucial role in effective MIRI alleviation. When compared to research on other mature mechanisms, the research studies on pyroptosis in MIRI are inadequate. Although many related protective drugs have been identified, these drugs generally lack clinical applications. It is necessary to further explore and verify these drugs to expand their applications in clinical setting. Early inhibition of MIRI by targeted regulation of pyroptosis is a key concern that needs to be addressed in future studies.

The Novel Peptide Chm-273s Has Therapeutic Potential for Metabolic Disorders: Evidence from In Vitro Studies and High-Sucrose Diet and High-Fat Diet Rodent Models

The aim of this study was to develop a novel peptide potentially applicable for the treatment of metabolic conditions, such as obesity and type 2 diabetes (T2D). We identified CHM-273S from the list of peptides from milk hydrolysate obtained by HPLC/MS-MS. In vitro analysis of primary murine fibroblasts indicated the potential of CHM-273S to upregulate IRS2 mRNA expression. CHM-273S showed a prominent anorexigenic effect in mice with the induction of a key mechanism of leptin signaling via STAT3 in the hypothalamus as a possible effector. In the animal model of metabolic disease, CHM-273S alleviated glucose intolerance and insulin resistance, and induced phosphorylation of Akt at Ser473 and Thr308 in the hepatocytes of high-sucrose diet-fed rats. In a murine model of T2D, CHM-273S mitigated high-fat diet-induced hyperglycemia and insulin resistance and improved low-grade inflammation by diminishing serum TNFα. Mice treated with chronic CHM-273S had a significant reduction in body weight, with a lower visceral fat pad weight and narrow adipocytes. The effects of the peptide administration were comparable to those of metformin. We show the potential of CHM-273S to alleviate diet-induced metabolic alterations in rodents, substantiating its further development as a therapeutic for obesity, T2D, and other metabolic conditions.

Macrophage Polarization Mediated by Mitochondrial Dysfunction Induces Adipose Tissue Inflammation in Obesity

Obesity is one of the prominent global health issues, contributing to the growing prevalence of insulin resistance and type 2 diabetes. Chronic inflammation in adipose tissue is considered as a key risk factor for the development of insulin resistance and type 2 diabetes in obese individuals. Macrophages are the most abundant immune cells in adipose tissue and play an important role in adipose tissue inflammation. Mitochondria are critical for regulating macrophage polarization, differentiation, and survival. Changes to mitochondrial metabolism and physiology induced by extracellular signals may underlie the corresponding state of macrophage activation. Macrophage mitochondrial dysfunction is a key mediator of obesity-induced macrophage inflammatory response and subsequent systemic insulin resistance. Mitochondrial dysfunction drives the activation of the NLRP3 inflammasome, which induces the release of IL-1β. IL-1β leads to decreased insulin sensitivity of insulin target cells via paracrine signaling or infiltration into the systemic circulation. In this review, we discuss the new findings on how obesity induces macrophage mitochondrial dysfunction and how mitochondrial dysfunction induces NLRP3 inflammasome activation. We also summarize therapeutic approaches targeting mitochondria for the treatment of diabetes.

A role for metformin in the treatment of Dupuytren disease?

Dupuytren disease (DD) is a hand-localized fibrotic disorder characterized by a scar-like, collagen-rich cord. Treatment usually comprises surgical removal of the cord, but is associated with a high relapse rate, in some cases requiring finger amputation. There is currently no consensual medical approach for treating DD. Numerous preclinical studies have highlighted antifibrotic properties of metformin, and the aim of this study was to assess a potential antifibrotic role of metformin in DD. Fibroblasts from DD cords (DF) and phenotypically normal palmar fascia (PF) were extracted from surgical specimens and cultured. The fibrotic status of DF and PF was compared at baseline, and under profibrotic (TGF-β stimulation) and antifibrotic (metformin stimulation) conditions, using quantitative RT-PCR, western blot, immunocytochemistry, and a functional fibroblast contraction assay. At baseline, DF showed higher levels of fibrotic markers and contraction capacity compared with PF. Both types of fibroblasts responded to TGF-β stimulation. Treatment of DF and PF with metformin did not affect basal levels of fibrotic markers and contraction but largely prevented their induction by TGF-β. In conclusion, our data show that metformin inhibits TGF-β-induced expression of fibrotic markers and contraction in hand-derived fibroblasts. This supports the case for a clinical trial to assess the repurposing of metformin as an adjuvant to surgery, to prevent, reduce, or delay recurrence in at-risk DD patients.

Molecular Evidence on the Inhibitory Potential of Metformin against Chlorpyrifos-Induced Neurotoxicity

Chlorpyrifos (CPF) is an organophosphorus (OP) pesticide, resulting in various health complications as the result of ingestion, inhalation, or skin absorption, and leads to DNA damage and increased oxidative stress. Metformin, derived from Galega officinalis, is reported to have anti-inflammatory and anti-apoptotic properties; thus, this study aimed to investigate the beneficial role of metformin in neurotoxicity induced by sub-acute exposure to CPF in Wistar rats. In this study, animals were divided into nine groups and were treated with different combinations of metformin and CPF. Following the 28 days of CPF and metformin administration, brain tissues were separated. The levels of inflammatory biomarkers such as tumor necrosis factor alpha (TNFα) and interleukin 1β (IL-1β), as well as the expression of 5HT1 and 5HT2 genes, were analyzed. Moreover, the levels of malondialdehyde (MDA), reactive oxygen species (ROS), and the ADP/ATP ratio, in addition to the activity of acetylcholinesterase (AChE) and superoxide dismutase (SOD), were tested through in vitro experiments. This study demonstrated the potential role of metformin in alleviating the mentioned biomarkers, which can be altered negatively as a result of CPF toxicity. Moreover, metformin showed protective potential in modulating inflammation, as well as oxidative stress, the expression of genes, and histological analysis, in a concentration-dependent manner.

Controversies in the Pathogenesis, Diagnosis and Treatment of PCOS: Focus on Insulin Resistance, Inflammation, and Hyperandrogenism

Polycystic ovary syndrome (PCOS) is a heterogeneous and extremely common disease with symptoms that vary with the age of the patient, typically characterized by hyperandrogenism, chronic oligo-anovulation, and/or several metabolic disorders. The syndrome includes various phenotypes, and the pathogenesis is multifactorial, often involving insulin resistance. This feature is closely related to ovarian dysfunction, inflammation, hyperandrogenism, and metabolic disorders, which characterize and complicate the syndrome. Therapy currently considers both lifestyle improvements and medications, and must be tailored on a case-by-case basis. To date, the published studies have not arrived at a definition of the most suitable therapy for each individual case and many of the drugs used are still off-label. In this review, we discuss some controversial diagnostic and therapeutic aspects of PCOS, such as the role of insulin resistance, inflammation, and hyperandrogenism. We also evaluated the advantages and disadvantages of contraceptive therapy and antiandrogens.

Plaque microstructures during metformin therapy in type 2 diabetic subjects with coronary artery disease: optical coherence tomography analysis

BACKGROUND

While metformin is recommended as a first-line cardioprotective therapy for type 2 diabetic patients, whether it exerts direct effects on atherosclerotic plaque remains uncertain. The current study characterized coronary plaque microstructures in type 2 diabetic patients who received metformin.

METHODS

We retrospectively analyzed 409 non-culprit lipid plaques in 313 type 2 diabetic patients with coronary artery disease (CAD) by using frequency-domain optical coherence tomography (FD-OCT) imaging. FD-OCT derived plaque microstructures were compared in patients stratified according to metformin use.

RESULTS

A proportion of 38.6% of study subjects received metformin. Patients receiving metformin more likely exhibited a history of hypertension (79.3% vs. 67.1%, P=0.03) and metabolic syndrome (52.8% vs. 36.4%, P=0.01). On FD-OCT imaging, the prevalence of lipid plaque was lower in the metformin group (66.2% vs. 77.9%, P=0.03). Furthermore, the metformin group demonstrated plaques with a smaller lipid arc (median: 168.7° vs. 208.5°, P=0.008), shorter longitudinal length (media: 5.1 vs. 9.1 mm, P=0.04), and a lower frequency of cholesterol crystal (3.9% vs. 18.2%, P=0.01) and spotty calcification (3.9% vs. 34.8%, P=0.008). These differences remained significant after adjusting for clinical characteristics and glycemic control. However, in patients who received insulin, the favourable effect of metformin on lipid arc was not observed (insulin user: P=0.87; insulin non-user: P=0.009; P value for interaction between two groups, P=0.02).

CONCLUSIONS

Metformin use was associated with a lower prevalence of vulnerable plaque features in type 2 diabetic patients with CAD, especially insulin non-user. These findings suggest the potential of metformin to exert direct plaque stabilization effects in type 2 diabetic subjects.

Metformin Ameliorates Inflammation and Airway Remodeling of Experimental Allergic Asthma in Mice by Restoring AMPKα Activity

Metformin has been involved in modulating inflammatory state and inhibiting cell proliferation and angiogenesis. This study aimed to determine whether metformin alleviates airway inflammation and remodeling of experimental allergic asthma and elucidate the underlying mechanism. We sensitized and challenged mice with ovalbumin (OVA) to induce allergic asthma. During the challenge period, metformin was administered by intraperitoneal injection. By histopathological and immunohistochemical analyses, metformin-treated mice showed a significant alleviation in airway inflammation, and in the parameters of airway remodeling including goblet cell hyperplasia, collagen deposition and airway smooth muscle hypertrophy compared to those in the OVA-challenged mice. We also observed elevated levels of multiple cytokines (IL-4, IL-5, IL-13, TNF-α, TGF-β1 and MMP-9) in the bronchoalveolar lavage fluid, OVA-specific IgE in the serum and angiogenesis-related factors (VEGF, SDF-1 and CXCR4) in the plasma from asthmatic mice, while metformin reduced all these parameters. Additionally, the activity of 5′-adenosine monophosphate-activated protein kinase a (AMPKα) in the lungs from OVA-challenged mice was remarkably lower than control ones, while after metformin treatment, the ratio of p-AMPKα to AMPKα was upregulated and new blood vessels in the sub-epithelial area as evidenced by CD31 staining were effectively suppressed. These results indicate that metformin ameliorates airway inflammation and remodeling in an OVA-induced chronic asthmatic model and its protective role could be associated with the restoration of AMPKα activity and decreased asthma-related angiogenesis.

Metformin accelerates zebrafish heart regeneration by inducing autophagy

Metformin is one of the most widely used drugs for type 2 diabetes and it also exhibits cardiovascular protective activity. However, the underlying mechanism of its action is not well understood. Here, we used an adult zebrafish model of heart cryoinjury, which mimics myocardial infarction in humans, and demonstrated that autophagy was significantly induced in the injured area. Through a systematic evaluation of the multiple cell types related to cardiac regeneration, we found that metformin enhanced the autophagic flux and improved epicardial, endocardial and vascular endothelial regeneration, accelerated transient collagen deposition and resolution, and induced cardiomyocyte proliferation. Whereas, when the autophagic flux was blocked, then all these processes were delayed. We also showed that metformin transiently enhanced the systolic function of the heart. Taken together, our results indicate that autophagy is positively involved in the metformin-induced acceleration of heart regeneration in zebrafish and suggest that this well-known diabetic drug has clinical value for the prevention and amelioration of myocardial infarction.