Metformin Down-regulates TNF-α Secretion via Suppression of Scavenger Receptors in Macrophages

Immunomodulatory effects of calorie restriction and its mimetics: A new potential therapeutic approach for autoimmune diseases

Calorie restriction (CR) is a well known intervention associated with multifaceted anti-aging and pro-longevity health benefits. It induces complex physiological cellular and molecular adaptations, resulting in the fine-tuning of metabolic and immune responses in both homeostatic and diseased states. It has thus been extensively studied both preclinically and clinically, uncovering its therapeutic potential against inflammatory conditions, particularly autoimmune diseases. CR mimetics (CRMs), that is, molecules that mimic CR's effects, have also been widely investigated to counteract inflammatory states associated with numerous diseases, including autoimmunity. However, a comprehensive overview of how CR and CRMs modulate different aspects of immune responses, thereby potentially modifying autoimmunity, is still lacking. Here, we reviewed the latest progress on the impacts of CR and CRMs on the immune system and the current evidence on their potential translation in the clinical management of people with autoimmune diseases. First, we summarized different types of CR and CRMs and their main mechanisms of action. We next reviewed comprehensively how CR and CRMs modulate immune cells and discussed up-to-date preclinical and clinical advances in using CR and CRMs in the context of some of the most common autoimmune diseases. Finally, challenges faced in CR-related research and its translation into the clinic are discussed. SIGNIFICANCE STATEMENT: Calorie restriction (CR) encompasses various approaches for daily or intermittent reduction in calorie intake while maintaining adequate nutrient intake. It acts through cell-intrinsic and -extrinsic pathways to modulate immune cell functions. CR is emerging as a strategy for autoimmune disease management. CR's effects could be partially mimicked by molecules called CR mimetics, which are proposed to achieve CR's effects without reducing food intake. CR and CR mimetics have been tested as promising potential therapeutics in preclinical and clinical autoimmune disease studies.

Metformin-mediated protection against Immunosenescence in diabetic cardiomyopathy: The potential roles of GDF-15 and klotho proteins

Diabetic cardiomyopathy (DCM) is a global health concern. However, studies examining the effect of metformin on diabetes-induced cardiac myocyte aging are lacking. This study aimed to investigate the protective effect of metformin against DCM involving modulation of macrophage phenotypes, growth differentiation factor-15 (GDF-15), and the anti-aging protein Klotho. Diabetes was induced in male Wistar rats using streptozotocin. Diabetic and nondiabetic rats were treated with metformin (200 mg/kg/day) and saline (control). DCM, inflammation, adhesion molecules, immunometabolic, and GDF-15 biomarkers were assessed using immunoassays. Western blotting was used to analyze Klotho expression. Macrophage phenotypes, senescence-associated-galactosidase (SA-β-gal), and p16INK4a were examined using immunohistochemistry, whereas the heart sections were histologically examined. The untreated diabetic rats showed increased serum troponin I and creatine kinase-MB levels, reflecting cardiac damage, which was confirmed via morphological changes and senescence. Klotho expression was decreased, indicating cardiac aging. Treatment with metformin reduced the heart weight-body weight ratio and lowered cardiac injury, inflammation, and adhesion molecule biomarker levels. It also reversed the histopathological changes induced by diabetes. It shifted macrophage polarization toward the M2 phenotype, decreased p16INK4a and SA-β-gal expression, and enhanced Klotho and GDF-15 expression. These findings revealed that diabetes induces cardiac aging by increasing senescence markers and decreasing the expression of Klotho. Metformin treatment protects against DCM by modulating macrophage phenotypes, attenuating immunosenescence-related dysregulation, and enhancing GDF-15 and Klotho expressions. Thus, metformin has potential clinical implications in alleviating DCM.

Metformin in gynecological disorders: pathogenic insights and therapeutic implications

Metformin, the most widely used anti-diabetic drug, has been demonstrated to exert various effects, including antioxidant, anti-inflammatory, anti-tumor, and cardioprotective properties. Due to its affordability and low toxicity profile, metformin is increasingly used to prevent or treat a wide range of gynecological disorders, as evidenced by epidemiological studies, clinical trials, and animal and in vitro studies. Trial findings for non-cancer conditions such as endometriosis, premature ovarian failure (POF), and uterine fibroids remain controversial and insufficient. However, most current clinical trials for polycystic ovarian syndrome (PCOS) and gynecological malignancies are ongoing phase II-III trials. The pharmacological effects of metformin have been shown to target the insulin-like growth factor (IGF), AMP-activated protein kinase (AMPK), phosphatidylinositol 3-kinase (PI3K)/AKT, MAPK, NF-κB, and other signal transduction pathways, highlighting its potential in the treatment of gynecological disorders. In this review, we discuss the biological impacts of metformin and the mechanisms of action pertinent to the treatment of different gynecological disorders.

Metformin as a disease-modifying therapy in osteoarthritis: bridging metabolism and joint health

Background

Osteoarthritis (OA) and impaired glucose tolerance (IGT) frequently coexist, leading to compounded clinical and metabolic challenges. This study investigates the effects of metformin in improving both clinical outcomes (pain, stiffness, physical function) and metabolic parameters (inflammatory markers, lipid profile, BMI) in patients with knee OA and IGT.

Methods

The study included 60 patients diagnosed with knee OA and IGT. Participants were divided into two groups: 26 patients received standard OA treatment without metformin (Without Metf), while 34 received metformin (500 mg twice daily) for 3 months, in addition to standard treatment (With Metf). Clinical assessments (WOMAC, Lequesne Algofunctional Index, KOOS, VAS) and metabolic markers (CRP, NLR, SOD, lipid profile, BMI) were measured before treatment, after 1 month, and after 3 months.

Results

The With Metf group showed significantly greater improvements in pain, stiffness, physical function, and quality of life compared to the Without Metf group. Metformin also led to significant reductions in inflammatory markers and improvements in lipid profiles and metabolic health indicators. The With Metf group demonstrated enhanced BMI, waist-to-hip ratio, and waist-to-height ratio. Furthermore, the need for increased NSAID doses was predicted by factors such as pain severity and inflammatory markers.

Conclusion

Metformin effectively alleviates osteoarthritis symptoms and improves metabolic health in patients with both OA and IGT. Further research is needed to explore its long-term effects on joint health, inflammatory markers, and its potential role in OA management in patients without IGT.

Investigating the effect of metformin on chemobrain: Reports from cells to bedside

Chemobrain can be defined as the development of cognitive side effects following chemotherapy, which is increasingly reported in cancer survivor patients. Chemobrain leads to reduced patients' quality of life by causing different symptoms ranging from strokes and seizures to memory loss and mood disorders. Metformin, an antidiabetic drug, has been proposed as a potential treatment to improve the symptoms of chemotherapy-induced cognitive dysfunction. Several benefits of metformin on chemobrain have been suggested, including anti-inflammation, anti-oxidative stress, restoring impaired mitochondrial function, stabilizing apoptosis, ameliorating impairments to dendritic spine density, normalizing brain senescence protein levels, and attenuating reductions in cell viability, along with reversing learning and memory deficits. These benefits occur through various pathways of metformin, including adenosine monophosphate-activated protein kinase (AMPK), TAp73, and phosphatidylinositol 3-kinase/protein kinase B (Akt) pathways. In addition, metformin can exert neuroprotective effects and restore deficits in brain homeostasis caused by chemotherapy. Furthermore, activation of AMPK following metformin therapy promotes autophagy, stimulates energy production, and improves cell survival. Metformin's interaction with Tap73 and Akt pathways allows for regulated cell proliferation in adult neural precursor cells and cell growth, respectively. Although the negative effects on cerebral function induced by chemotherapeutics have been alleviated by metformin in several instances, further studies are required to confirm its beneficial effects. This research is essential as it addresses the pressing issue of chemobrain, which is on the rise alongside global increases in cancer. Exploring metformin's potential as a neuroprotective agent offers a promising avenue for mitigating these cognitive impairments and highlights the need for further studies to validate its therapeutic mechanisms. This review comprehensively summarises evidence from both in vitro and in vivo studies to demonstrate metformin's effects on cognitive function when co-administered with chemotherapy and identifies gaps in knowledge for further investigation.

Metformin attenuates inflammation and improves insulin sensitivity in coculture of LPS-induced 3T3-L1 adipocytes and RAW 264.7 macrophages mediated by IRS-1/GLUT-4 pathway

OBJECTIVE

Metformin is an anti-diabetic drug used to control blood glucose levels. The effects of metformin on insulin sensitivity in inflammation-induced adipocytes are not fully understood.This study aimed to explore the mechanism of metformin on insulin sensitivity enhancement in the coculture of LPS-induced 3T3-L1 adipocytes and RAW 264.7 macrophages.

MATERIAL AND METHODS

Insulin resistance was induced in coculture cells using Lipopolysaccharide, followed by adding 25, 50, and 100 µg/ml of metformin for 24 h of incubation. Glucose consumption, GLUT-4, IRS-1, and IL-6 mRNA expressions were quantified.

RESULTS

Metformin, starting at a concentration of 25 µg/ml, enhanced glucose consumption, upregulated GLUT-4 mRNA expression, and stimulated the expression of IRS-1 mRNA in coculture cells at 100 µg/ml of concentration. Additionally, Metformin inhibited inflammation by reducing IL-6 mRNA expression in coculture cells up to 100 µg/ml.

DISCUSSION AND CONCLUSION

These findings suggest that metformin attenuated inflammation and improved insulin sensitivity in inflammation-induced adipocytes that may be mediated by the IRS-1/GLUT-4 pathway.

Metformin and fibromyalgia pathophysiology: current insights and promising future therapeutic strategies

Fibromyalgia (FM) is a complex, chronic pain syndrome characterized by widespread musculoskeletal pain, fatigue, and cognitive disturbances. Despite its prevalence, the pathophysiology of FM remains poorly understood, with current treatments often providing limited relief. Recent studies have suggested that metformin, a widely used antidiabetic drug, may have potential therapeutic benefits for chronic pain conditions, including FM. This review aims to provide current insights into the role of metformin in FM pathophysiology, focusing on its neurotransmitter-modulating and anti-inflammatory effects. Metformin has been shown to mitigate neuroinflammation, protect neural tissues, and modulate key neurotransmitters involved in pain and mood regulation. These effects are particularly evident in animal models, where metformin has been observed to reduce pain sensitivity, improve mood-related behaviors, and decrease levels of pro-inflammatory cytokines like interleukin 1-beta (IL-1β). Additionally, the ability of metformin to influence serotonin, norepinephrine, and glutamate levels suggests a potential mechanism for its analgesic and mood-stabilizing effects. However, the current evidence is largely preclinical, and further research is needed to confirm these findings in human studies. This review aims to encourage researchers to explore the association between metformin and FM more deeply, with the hope of uncovering new therapeutic strategies that could offer relief to FM patients.

Metformin in Antiviral Therapy: Evidence and Perspectives

Metformin, a widely used antidiabetic medication, has emerged as a promising broad-spectrum antiviral agent due to its ability to modulate cellular pathways essential for viral replication. By activating AMPK, metformin depletes cellular energy reserves that viruses rely on, effectively limiting the replication of pathogens such as influenza, HIV, SARS-CoV-2, HBV, and HCV. Its role in inhibiting the mTOR pathway, crucial for viral protein synthesis and reactivation, is particularly significant in managing infections caused by HIV, CMV, and EBV. Furthermore, metformin reduces oxidative stress and reactive oxygen species (ROS), which are critical for replicating arboviruses such as Zika and dengue. The drug also regulates immune responses, cellular differentiation, and inflammation, disrupting the life cycle of HPV and potentially other viruses. These diverse mechanisms suppress viral replication, enhance immune system functionality, and contribute to better clinical outcomes. This multifaceted approach highlights metformin's potential as an adjunctive therapy in treating a wide range of viral infections.

Metformin protects against small intestine damage induced by diabetes and dunning's prostate cancer: A biochemical and histological study

The oral biguanide metformin is used to treat type 2 diabetic mellitus (T2DM). Anti-cancer effects have been proven by metformin in different hormone-sensitive tumors, including breast, pancreatic, colon, and prostate cancer. Therefore, we investigated whether metformin could defend against small intestine damage in Dunning's prostate cancer. The study divided the six groups of male Copenhagen rats into the following categories: control, diabetic (D), cancer (C), diabetic + cancer (DC), cancer + metformin (CM), and diabetic + cancer + metformin (DCM). After sacrifice, the small intestines were removed to assess biochemical markers and histopathological evaluation. Biochemical evaluations showed that glutathione (reduced) levels and other enzyme activities related antioxidant systems, paraoxonase, sodium potassium ATPase, acetylcholinesterase activities were decreased. In contrast, lipid peroxidation, total oxidant status, reactive oxygen species, interleukin-1β, interleukin-6, tumor necrosis factor-α, sucrase, maltase, trypsin, myeloperoxidase, xanthine oxidase activities, protein carbonyl contents and sialic acid levels were raised in the damaged groups. Treatment with metformin restored all of this. The histological assessment revealed moderate to severe damage in the small intestine following processes D and C. According to the study's findings, metformin treatment led to a notable decline in histopathological damage in the C and DC. A slight lowering in inflammatory cells and an improvement in the damaged gland integrity in the small intestine were noted with metformin treatment.​ Metformin use protected the small intestinal tissue damage and decreased oxidative stress.

Discovering mechanisms of macrophage tissue infiltration with Drosophila

Much is known about the importance of macrophages for regulating diverse aspects of organismal physiology, alongside their essential roles in inflammation. Relatively unexplored are the processes influencing macrophages' and monocytes' ability to invade into the tissues where they carry out these functions. Drosophila plasmatocytes, also called hemocytes, show similarities to vertebrate macrophages in their function and their molecular specification; they have recently been shown to also infiltrate into tissues during development and inflammation. Extravasation across vasculature, into tumors, the brain, and adipose tissue have all been observed. We discuss the striking parallels in some of these systems to vertebrate immune responses, including a requirement for tumor necrosis factor. Finally, we highlight the new pathways regulating infiltration found in the fly that remain as yet unexamined in a vertebrate context.

Repurposing metformin as adjuvant therapy in patients with ulcerative colitis treated with mesalamine: A randomized controlled double-blinded study

BACKGROUND

Ulcerative colitis (UC) is a type of inflammatory bowel disease associated with persistent inflammation. Animal studies proved the efficacy of metformin in UC.

AIM

To investigate the potential role of metformin and its protective pathways in patients with UC.

METHODS

This is a randomized, controlled, and double-blinded clinical trial that included 60 participants with mild to moderate UC and was divided randomly into two groups (n = 30). For 6 months, the mesalamine group received 1 g of mesalamine three times daily (t.i.d.). For six months, the metformin group received mesalamine 1 g t.i.d. and metformin 500 mg twice daily. A gastroenterologist evaluated patients at baseline and 6 months after starting the treatment in order to measure serum levels of zonulin, sphingosine 1 phosphate (S1P), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Biopsies from the colon were used to measure gene expression of zonula occuldin-1 (ZO-1), signal transducer and activator of factor-3 (STAT-3), and intracellular adhesion molecule-1 (ICAM-1). The numeric pain rating scale (NRS) and partial Mayo score were also assessed for each patient.

RESULTS

When compared to the mesalamine group, the metformin group demonstrated a statistical decrease in serum IL-6, zonulin, TNF-α, SIP, gene expression of ICAM-1 and STAT-3, and a significant increase in colonic ZO-1 when compared to the mesalamine group. The metformin group also showed a significant decrease in NRS and partial Mayo score index in comparison with the mesalamine group.

CONCLUSION

Metformin may be a promising additional therapy for UC patients. Trial registration identifier: NCT05553704.

Erythrina subumbrans (Hassk) Merr. (Fabaceae) Inhibits Insulin Resistance in the Adipose Tissue of High Fructose-Induced Wistar Rats

Background

The twigs and roots of Erythrina subumbrans (Hassk). Merr. Was reported to possess antidiabetic activity by reducing the activity of α-glucosidase and α-amylase. TNF-α is a pro-inflammatory cytokine in obesity and diabetes mellitus (DM). It inhibits the action of insulin, causing insulin resistance. Adiponectin is an anti-inflammatory peptide synthesized in white adipose tissue (WAT) and its high levels are linked with a decreased risk of DM. However, information about the effect of Erythrina subumbrans (Hassk). Merr. on insulin resistance are still lacking.

Purpose

To obtain the effects of the ethanol extract of E. subumbrans (Hassk) Merr. leaves (EES) in improving insulin resistance conditions.

Methods

The leaves were collected at Ciamis, West Java, Indonesia, and were extracted using ethanol 96%. The effects of EES were studied in fructose-induced adult male Wistar rats by performing the insulin tolerance test (ITT) and assessing blood glucose, TNF-α, adiponectin, and FFA levels. The number of WAT and BAT of the adipose tissues was also studied. The total phenols and flavonoids in EES were determined by the spectrophotometric method and the presence of quercetin in EES was analyzed using the LC-MS method.

Results

EES significantly reduced % weight gain, TNF-α levels, and increased adiponectin levels in fructose-induced Wistar rats. EES significantly reduced the FFA levels of fructose-induced Wistar rats and significantly affected the formation of BAT similar to that of metformin. All rats in EES and metformin groups improved insulin resistance as proven by higher ITT values (3.01 ± 0.91 for EES 100 mg/kg BW; 3.01 ± 1.22 for EES 200 mg/kg BW; 5.86 ± 3.13 for EES 400 mg/kg BW; and 6.44 ± 2.58 for metformin) compared with the fructose-induced group without treatment (ITT = 2.62 ± 1.38). EES contains polyphenol compounds (2.7638 ± 0.0430 mg GAE/g extract), flavonoids (1.9626 ± 0.0152 mg QE/g extract), and quercetin 0.246 µg/mL at m/z 301.4744.

Conclusion

Erythrina subumbrans (Hassk). Merr. extract may have the potential to be further explored for its activity in improving insulin resistance conditions. However, further studies are needed to confirm its role in alleviating metabolic disorders.

Favorable Antiviral Effect of Metformin on SARS-CoV-2 Viral Load in a Randomized, Placebo-Controlled Clinical Trial of COVID-19

BACKGROUND

Metformin has antiviral activity against RNA viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The mechanism appears to be suppression of protein translation via targeting the host mechanistic target of rapamycin pathway. In the COVID-OUT randomized trial for outpatient coronavirus disease 2019 (COVID-19), metformin reduced the odds of hospitalizations/death through 28 days by 58%, of emergency department visits/hospitalizations/death through 14 days by 42%, and of long COVID through 10 months by 42%.

METHODS

COVID-OUT was a 2 × 3 randomized, placebo-controlled, double-blind trial that assessed metformin, fluvoxamine, and ivermectin; 999 participants self-collected anterior nasal swabs on day 1 (n = 945), day 5 (n = 871), and day 10 (n = 775). Viral load was quantified using reverse-transcription quantitative polymerase chain reaction.

RESULTS

The mean SARS-CoV-2 viral load was reduced 3.6-fold with metformin relative to placebo (-0.56 log10 copies/mL; 95% confidence interval [CI], -1.05 to -.06; P = .027). Those who received metformin were less likely to have a detectable viral load than placebo at day 5 or day 10 (odds ratio [OR], 0.72; 95% CI, .55 to .94). Viral rebound, defined as a higher viral load at day 10 than day 5, was less frequent with metformin (3.28%) than placebo (5.95%; OR, 0.68; 95% CI, .36 to 1.29). The metformin effect was consistent across subgroups and increased over time. Neither ivermectin nor fluvoxamine showed effect over placebo.

CONCLUSIONS

In this randomized, placebo-controlled trial of outpatient treatment of SARS-CoV-2, metformin significantly reduced SARS-CoV-2 viral load, which may explain the clinical benefits in this trial. Metformin is pleiotropic with other actions that are relevant to COVID-19 pathophysiology.

CLINICAL TRIALS REGISTRATION

NCT04510194.

Renoprotective effect of a novel combination of 6-gingerol and metformin in high-fat diet/streptozotocin-induced diabetic nephropathy in rats via targeting miRNA-146a, miRNA-223, TLR4/TRAF6/NLRP3 inflammasome pathway and HIF-1α

BACKGROUND

MiRNA-146a and miRNA-223 are key epigenetic regulators of toll-like receptor 4 (TLR4)/tumor necrosis factor-receptor-associated factor 6 (TRAF6)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome pathway, which is involved in diabetic nephropathy (DN) pathogenesis. The currently available oral anti-diabetic treatments have been insufficient to halt DN development and progression. Therefore, this work aimed to assess the renoprotective effect of the natural compound 6-gingerol (GR) either alone or in combination with metformin (MET) in high-fat diet/streptozotocin-induced DN in rats. The proposed molecular mechanisms were also investigated.

METHODS

Oral gavage of 6-gingerol (100 mg/kg) and metformin (300 mg/kg) were administered to rats daily for eight weeks. MiRNA-146a, miRNA-223, TLR4, TRAF6, nuclear factor-kappa B (NF-κB) (p65), NLRP3, caspase-1, and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA expressions were measured using real-time PCR. ELISA was used to measure TLR4, TRAF6, NLRP3, caspase-1, tumor necrosis factor-alpha (TNF-α), and interleukin-1-beta (IL-1β) renal tissue levels. Renal tissue histopathology and immunohistochemical examination of fibronectin and NF-κB (p65) were performed.

RESULTS

6-Gingerol treatment significantly reduced kidney tissue damage and fibrosis. 6-Gingerol up-regulated miRNA-146a and miRNA-223 and reduced TLR4, TRAF6, NF-κB (p65), NLRP3, caspase-1, TNF-α, IL-1β, HIF-1α and fibronectin renal expressions. 6-Gingerol improved lipid profile and renal functions, attenuated renal hypertrophy, increased reduced glutathione, and decreased blood glucose and malondialdehyde levels. 6-Gingerol and metformin combination showed superior renoprotective effects than either alone.

CONCLUSION

6-Gingerol demonstrated a key protective role in DN by induction of miRNA-146a and miRNA-223 expression and inhibition of TLR4/TRAF6/NLRP3 inflammasome signaling. 6-Gingerol, a safe, affordable, and abundant natural compound, holds promise for use as an adjuvant therapy with metformin in diabetic patients to attenuate renal damage and stop the progression of DN.

LncRNA DANCR promotes macrophage lipid accumulation through modulation of membrane cholesterol transporters

The progression of atherosclerosis (AS), the pathological foundation of coronary artery disease (CAD), is featured by massive lipid deposition in the vessel wall. LncRNAs are implicated in lipid disorder and AS, whereas the specific role of lncRNA DANCR in atherogenesis remains unknown. Here, we demonstrated that DANCR promotes macrophage lipid accumulation by regulating the expression of membrane cholesterol transport proteins. qPCR showed that compared to control groups, CAD patients and atherosclerotic mice had higher DANCR levels. Treating human THP-1 macrophages and mouse RAW264.7 macrophages with ox-LDL significantly upregulated the expression levels of DANCR. Oil Red O staining showed that the silence of DANCR robustly reduced, while overexpression of DANCR significantly increased the numbers and size of lipid droplets in ox-LDL-treated THP-1 macrophages. In contrast, the opposite phenomena were observed in DANCR overexpressing cells. The expression of ABCA1, ABCG1, SR-BI, and NBD-cholesterol efflux was increased obviously by DANCR inhibition and decreased by DANCR overexpression, respectively. Furthermore, transfection with DANCR siRNA induced a robust decrease in the levels of CD36, SR-A, and Dil-ox-LDL uptake, while DANCR overexpression amplified the expression of CD36, SR-A and the uptake of Dil-ox-LDL in lipid-laden macrophages. Lastly, we found that the effects of DANCR on macrophage lipid accumulation and the expression of membrane cholesterol transport proteins were not likely related to miR-33a. The present study unraveled the adverse role of DANCR in foam cell formation and its relationship with cholesterol transport proteins. However, the competing endogenous RNA network underlying these phenomena warrants further exploration.

Evaluating the Antihyperalgesic Potential of Sildenafil-Metformin Combination and Its Impact on Biochemical Markers in Alloxan-Induced Diabetic Neuropathy in Rats

(1) Background: Globally, about 600 million people are afflicted with diabetes, and one of its most prevalent complications is neuropathy, a debilitating condition. At the present time, the exploration of novel therapies for alleviating diabetic-neuropathy-associated pain is genuinely captivating, considering that current therapeutic options are characterized by poor efficacy and significant risk of side effects. In the current research, we evaluated the antihyperalgesic effect the sildenafil (phosphodiesterase-5 inhibitor)-metformin (antihyperglycemic agent) combination and its impact on biochemical markers in alloxan-induced diabetic neuropathy in rats. (2) Methods: This study involved a cohort of 70 diabetic rats and 10 non-diabetic rats. Diabetic neuropathy was induced by a single dose of 130 mg/kg alloxan. The rats were submitted to thermal stimulus test using a hot-cold plate and to tactile stimulus test using von Frey filaments. Moreover, at the end of the experiment, the animals were sacrificed and their brains and livers were collected to investigate the impact of this combination on TNF-α, IL-6, nitrites and thiols levels. (3) Results: The results demonstrated that all sildenafil-metformin combinations decreased the pain sensitivity in the von Frey test, hot plate test and cold plate test. Furthermore, alterations in nitrites and thiols concentrations and pro-inflammatory cytokines (specifically TNF-α and IL-6) were noted following a 15-day regimen of various sildenafil-metformin combinations. (4) Conclusions: The combination of sildenafil and metformin has a synergistic effect on alleviating pain in alloxan-induced diabetic neuropathy rats. Additionally, the combination effectively decreased inflammation, inhibited the rise in NOS activity, and provided protection against glutathione depletion.

Effects of metformin on arterial elasticity and pro-inflammatory markers in black diabetes patients

Background

Pro-inflammatory markers are linked with the development and progression of type 2 diabetes mellitus and arterial stiffening. Pulse Wave Velocity (PWV) and Augmentation Index (Aix) are non-invasive standard markers of arterial elasticity and predictors of cardiovascular mortality and morbidity.

Aim

To investigate the effects of metformin alone and in combination with glimepiride on arterial elasticity, pro-inflammatory cytokines in black type 2 diabetes mellitus patients.

Settings

Participants were enrolled from Sefako Makgatho Health Sciences University community, Gauteng, South Africa.

Methods

PWV and Aix were measured using the AtCor SphygmoCor® system (AtCor Medical, Inc., Sydney, Australia). Cytokines levels were measured using Multiplexing with Bio-Plex Pro™ human inflammation panel I assay. Treatment naïve type 2 diabetes participants were divided into two groups: metformin (M) (n = 10) and metformin glimepiride (MS) (n = 14). The study participants were followed up at 4 and 8 months after treatment initiation.

Results

In the M and MS, IL-1β increased significantly at four months (58.19 ± 0.03 pg/ml, 58.35 ± 0.30 pg/ml) when compared to baseline (33.05 ± 18.56 pg/ml, 34.79 ± 18.77 pg/ml) then decreased significantly at eight months (29.25 ± 11.64 pg/ml, 32.54 ± 14.26 pg/ml) when compared to four months (58.19 ± 0.03 pg/ml, 58.35 ± 0.3 pg/ml) (p < 0.05). There were no significant changes in PWV, Aix, IL-1ra, IL-2, IL-6, IL-8, TNF-α and hs-CRP levels at both treatment intervals.

Conclusion

Metformin alone or in combination with glimepiride did not improve arterial elasticity and did not reduce pro-inflammatory cytokines levels in T2DM black South African patients.

Contribution

The context-based knowledge generated by the current study is expected to enhance the continuum of care for T2DM patients.

Low-grade inflammation in the post-COVID period as a strategic goal of treatment and rehabilitation

As of the beginning of 2023, there are more than 660 million convalescents of a new coronavirus infection in the world, however, even despite successful treatment of the acute period of the disease, such patients have a high risk of developing long-term complications in the post-COVID period, primarily cardiovascular events. One factor that seriously increases the risk of these complications is the state of lowgrade systemic inflammation (LGSI). LGSI is not a clinical diagnosis, it is characterized by a level of C-reactive protein in peripheral blood in the range of 3–10 mg/l and is most often detected during routine examination of patients, who in most cases have no clinical symptoms. In this regard, the condition of LGSI most often remains unnoticed and unreasonably ignored, despite quite extensive literature data on the effect of LGSI on the pathogenesis of many cardiovascular diseases. The development of drug therapy for LGSI is complicated by the multifactorial etiology of this condition. The causes of LGSI can be both genetic factors, which are practically impossible to correct, and conditions that are amenable to drug and non-drug treatment, such as, for example, increased intestinal permeability to pro-inflammatory agents, including lipopolysaccharide of gram-negative flora, the presence of a chronic untreated infection site and endocrine pathology (obesity and type 2 diabetes). This review presents the main information to date on the state of LGSI in patients who had a new coronavirus infection, including the results of our own observations of patients who have undergone a course of rehabilitation measures, as well as the most significant, in our opinion, factors predisposing to the development of LGSI in such patients.

Efficacy of metformin on different adipocytokines in type 2 diabetes mellitus patients

Background

Type 2 diabetes mellitus is a major medical condition that constitutes a significant financial burden on most healthcare systems.

Objective

The current research aimed to evaluate the antidiabetic, anti-inflammatory, and antihyperlipidemic effects of 500 mg metformin twice daily for 6 months on various adipocytokines in type 2 diabetes mellitus patients.

Patients and methods

The participants in this study were divided into three groups: the control, the untreated diabetic, and the metformin-treated diabetic groups.

Results and conclusion

Metformin treatment significantly improved the poor oral glucose tolerance and the lowered serum levels of insulin and C-peptide with subsequent better homeostatic model assessment for insulin resistance and sensitivity and β-cell function results. Moreover, metformin treatment significantly decreased the elevated serum levels of glycosylated hemoglobin, high, low, and very low-density lipoproteins, adipokines (visfatin and resistin), and retinol-binding protein-4 expression, with a significant increase in total cholesterol and triglycerides. Metformin also reduced the proinflammatory cytokine expressions (interleukin-1β, interferon-γ, and tumor-necrosis factor-α). In conclusion, metformin can alleviate adipocytokines through anti-inflammatory effects, synergizing with its antidiabetic actions.

Role of CD36 in central nervous system diseases

CD36 is a highly glycosylated integral membrane protein that belongs to the scavenger receptor class B family and regulates the pathological progress of metabolic diseases. CD36 was recently found to be widely expressed in various cell types in the nervous system, including endothelial cells, pericytes, astrocytes, and microglia. CD36 mediates a number of regulatory processes, such as endothelial dysfunction, oxidative stress, mitochondrial dysfunction, and inflammatory responses, which are involved in many central nervous system diseases, such as stroke, Alzheimer's disease, Parkinson's disease, and spinal cord injury. CD36 antagonists can suppress CD36 expression or prevent CD36 binding to its ligand, thereby achieving inhibition of CD36-mediated pathways or functions. Here, we reviewed the mechanisms of action of CD36 antagonists, such as Salvianolic acid B, tanshinone IIA, curcumin, sulfosuccinimidyl oleate, antioxidants, and small-molecule compounds. Moreover, we predicted the structures of binding sites between CD36 and antagonists. These sites can provide targets for more efficient and safer CD36 antagonists for the treatment of central nervous system diseases.

Metformin exerts anti-liver fibrosis effect based on the regulation of gut microbiota homeostasis and multi-target synergy

Liver fibrosis can progress to cirrhosis if left untreated. Therefore, identifying effective antifibrotic drugs is crucial. This study aimed to investigate the role and potential mechanism of metformin in treating hepatic fibrosis based on the synergistic effect of multiple targets and the "intestine-liver axis" theory. A CCl4-induced liver fibrosis mouse model was established. We measured liver function, liver fibrosis indicators, oxidative stress and inflammation indices. Hematoxylin and eosin and Masson's trichrome staining were used to detect collagen deposition. The expression of apoptotic proteins, TGF-β/Smads and TIMP-1/MMPs was assessed. 16S rRNA and untargeted metabolomics (liquid chromatography-mass spectrometry) were used to assess mouse intestinal flora and metabolites, performing a comprehensive correlation analysis. Metformin improved the general status and liver function and decreased liver collagen deposition in CCl4-induced liver fibrotic mice. Compared with the control group, IL-6, TNF-α and COX-2 serum levels in the liver fibrosis group increased. Although not significantly different, the serum inflammatory marker levels in the metformin group were lower than those in the model group. Metformin decreased serum MDA and increased serum SOD activity, which increased and decreased, respectively, in the model group. Furthermore, metformin inhibited liver cell apoptosis, TGF-β1 expression and TIMP-1, while promoting Smad7 expression, MMP-1 and MMP-2 in fibrotic mice. 16S rRNA analysis indicated that metformin significantly ameliorated the Bacteroides, Helicobacter, Parabacteroides and Parasutterella imbalance. We identified 385 differential metabolites between the metformin and model groups. Prevotella abundance significantly decreased in the metformin group and positively correlated with decreased taurocholic acid levels. Metformin potentially reverses liver fibrosis by inhibiting inflammation, mitigating oxidative stress damage and suppressing hepatocyte apoptosis via intestinal flora metabolite regulation. Metformin also regulates the TGF-β/Smads and TIMP-1/MMPs signalling pathways. This study provides a theoretical basis for the clinical use of metformin in patients with liver fibrosis.

Metformin use is associated with decreased asthma exacerbations in adolescents and young adults

RATIONALE

Metformin is a commonly used antidiabetes medication with suggested anti-inflammatory and antioxidative effects. Metformin use has been associated with lower risk of asthma exacerbations and hospitalizations in adults. Here, we aimed to evaluate how asthma exacerbation rates changed after adolescents and young adults were prescribed metformin, and to learn if those changes were related to metformin prescription adherence.

METHODS

Using secondary data of patients between 12 and 20 years old with asthma diagnosis and a metformin prescription from the Arkansas All Payers Claim Database and Arkansas School body mass index (BMI) database, we estimated the change in annualized asthma exacerbation rates after metformin prescription. We also evaluated the association of prescription adherence to the changes in those rates using univariate and multivariate regression models.

RESULTS

A total of 464 patients met inclusion criteria. Outpatient exacerbation rates decreased after metformin prescription (13.4% only before vs. 7.8% only after, p = .009), and the annualized rate decreased more after metformin prescription as adherence increased (rank r = -.165, p < .001). After adjusting for potential confounders-age, sex, BMI, and inhaled corticoid steroid use-the strength of the association was attenuated.

CONCLUSIONS

Asthma exacerbation rates decreased after metformin prescription, but a larger sample of patients who have experienced exacerbations and including patients with asthma who have not been prescribed metformin is needed to better know whether these decreases are driven by metformin use.

Mechanisms and effects of metformin on skeletal muscle disorders

Skeletal muscle disorders are mostly genetic and include several rare diseases. With disease progression, muscle fibrosis and adiposis occur, resulting in limited mobility. The long course of these diseases combined with limited treatment options affect patients both psychologically and economically, hence the development of novel treatments for neuromuscular diseases is crucial to obtain a better quality of life. As a widely used hypoglycemic drug in clinical practice, metformin not only has anti-inflammatory, autophagy-regulating, and mitochondrial biogenesis-regulating effects, but it has also been reported to improve the symptoms of neuromuscular diseases, delay hypokinesia, and regulate skeletal muscle mass. However, metformin's specific mechanism of action in neuromuscular diseases requires further elucidation. This review summarizes the evidence showing that metformin can regulate inflammation, autophagy, and mitochondrial biogenesis through different pathways, and further explores its mechanism of action in Duchenne muscular dystrophy, statin-associated muscle disorders, and age-related sarcopenia. This review clarifies the directions of future research on therapy for neuromuscular diseases.

Anti‑inflammatory effect of metformin against an experimental model of LPS‑induced cytokine storm

Cytokine storm is one of the leading causes of death in patients with COVID-19. Metformin has been shown to inhibit the action of a wide range of proinflammatory cytokines such as IL-6, and TNF-α which may ultimately affect cytokine storm due to Covid-19. The present study analyzed the anti-inflammatory effect of oral and intraperitoneal (IP) metformin administration routes in a mouse model of lipopolysaccharide (LPS)-induced cytokine storm. A total of 60 female BALB/c mice were randomly assigned to one of six groups: i) Control; ii) LPS model; iii) oral saline + LPS; iv) oral metformin + LPS; v) IP saline + LPS; and vi) IP metformin + LPS. Metformin or saline were administered to the mice for 30 days, after which an IP injection of 0.5 mg/kg LPS induced a cytokine storm in the five treatment groups. Mice were sacrificed and serum cytokine levels were measured. Pretreatment of mice with either oral or IP metformin significantly reduced the increase in IL-1, IL-6 and TNF-α following LPS injection. Both metformin administration routes significantly reduced IL-1 and TNF-α levels, although IP metformin appeared to be significantly more effective at reducing IL-6 levels compared with oral metformin. Neither the oral or IP route of administration of metformin demonstrated a significant effect on IL-17 levels. Based on its ability to suppress the proinflammatory LPS-induced cytokine storm, metformin may have future potential benefits in ameliorating human diseases caused by elevated cytokine levels.

The Influence of Sildenafil-Metformin Combination on Hyperalgesia and Biochemical Markers in Diabetic Neuropathy in Mice

Background and objectives: Worldwide, approximately 500 million people suffer from diabetes and at least 50% of these people develop neuropathy. Currently, therapeutic strategies for reducing diabetic neuropathy (DN)-associated pain are limited and have several side effects. The purpose of the study was to evaluate the antihyperalgesic action of different sildenafil (phosphodiesterase-5 inhibitor) and metformin (antihyperglycemic agent) combinations in alloxan-induced DN. Methods: The study included 100 diabetic mice and 20 non-diabetic mice that were subjected to hot and cold stimulus tests. Furthermore, we determined the influence of this combination on TNF-α, IL-6 and nitrites levels in brain and liver tissues. Results: In both the hot-plate and tail withdrawal test, all sildenafil-metformin combinations administered in our study showed a significant increase in pain reaction latencies when compared to the diabetic control group. Furthermore, all combinations decreased blood glucose levels due to the hypoglycemic effect of metformin. Additionally, changes in nitrite levels and pro-inflammatory cytokines (TNF-α and IL-6) were observed after 14 days of treatment with different sildenafil-metformin combinations. Conclusions: The combination of these two substances increased the pain reaction latency of diabetic animals in a dose-dependent manner. Moreover, all sildenafil-metformin combinations significantly reduced the concentration of nitrites in the brain and liver, which are final products formed under the action of iNOS.

A pilot metabolomic study of drug interaction with the immune response to seasonal influenza vaccination

Many human diseases, including metabolic diseases, are intertwined with the immune system. The understanding of how the human immune system interacts with pharmaceutical drugs is still limited, and epidemiological studies only start to emerge. As the metabolomics technology matures, both drug metabolites and biological responses can be measured in the same global profiling data. Therefore, a new opportunity presents itself to study the interactions between pharmaceutical drugs and immune system in the high-resolution mass spectrometry data. We report here a double-blinded pilot study of seasonal influenza vaccination, where half of the participants received daily metformin administration. Global metabolomics was measured in the plasma samples at six timepoints. Metformin signatures were successfully identified in the metabolomics data. Statistically significant metabolite features were found both for the vaccination effect and for the drug-vaccine interactions. This study demonstrates the concept of using metabolomics to investigate drug interaction with the immune response in human samples directly at molecular levels.

Metformin reduces SARS-CoV-2 in a Phase 3 Randomized Placebo Controlled Clinical Trial

Current antiviral treatment options for SARS-CoV-2 infections are not available globally, cannot be used with many medications, and are limited to virus-specific targets.1-3 Biophysical modeling of SARS-CoV-2 replication predicted that protein translation is an especially attractive target for antiviral therapy.4 Literature review identified metformin, widely known as a treatment for diabetes, as a potential suppressor of protein translation via targeting of the host mTor pathway.5 In vitro, metformin has antiviral activity against RNA viruses including SARS-CoV-2.6,7 In the COVID-OUT phase 3, randomized, placebo-controlled trial of outpatient treatment of COVID-19, metformin had a 42% reduction in ER visits/hospitalizations/death through 14 days; a 58% reduction in hospitalizations/death through 28 days, and a 42% reduction in Long COVID through 10 months.8,9 Here we show viral load analysis of specimens collected in the COVID-OUT trial that the mean SARS-CoV-2 viral load was reduced 3.6-fold with metformin relative to placebo (-0.56 log10 copies/mL; 95%CI, -1.05 to -0.06, p=0.027) while there was no virologic effect for ivermectin or fluvoxamine vs placebo. The metformin effect was consistent across subgroups and with emerging data.10,11 Our results demonstrate, consistent with model predictions, that a safe, widely available,12 well-tolerated, and inexpensive oral medication, metformin, can be repurposed to significantly reduce SARS-CoV-2 viral load.

Drug repurposing: Metformin's effect against liver tissue damage in diabetes and prostate cancer model

Background

There are evidences linking diabetes to the pathogenesis and progression of various cancers. Metformin is a well-known antidiabetic drug that reduces the levels of circulating glucose and insulin in patients with both insulin resistance and hyperinsulinemia. Aim of the present study was to evaluate the effect of metformin on the liver of rats bearing prostate cancer, diabetes and prostate cancer + diabetes via histopathological and biochemical methods.

Methods

Male Copenhagen rats were divided into six groups. Control group, diabetic group, cancer group, diabetic + cancer group, diabetic + cancer + metformin group, cancer + metformin group. Diabetes was induced by injecting single dose of streptozotocin (65 mg/kg) to Copenhagen rats, cancer induced 2 × 104 Mat-LyLu cells. Metformin treatment was administered daily by gavage following inocculation of the Mat- Lylu cells to fifth and sixth group. The experiment was terminated on the 14th day following Mat-LyLu cell injection. At the end of the experimental period, the rats were sacrificed, and liver tissue was taken. Liver damage was scored. Biochemically, serum prostate-specific antigen level was determined by employing Enzyme Linked Immuno Sorbent Assay method. In addition, the activities of different enzyme and biochemical parameters were determined spectrophotometrically inform the hepatic tissue specimens.

Results

The findings of this study reveal that histopathological and biochemical damage in cancer and diabetic + cancer groups decreased significantly in the metformin treated groups.

Conclusion

These highlights that the antidiabetic drug metformin can be repositioned for attenuating liver tissue damage associated with prostate cancer and diabetes.

Pleiotropic Effects of Metformin in Osteoarthritis

The involvement of the knee joint is the most common localization of the pathological process in osteoarthritis (OA), which is associated with obesity in over 50% of the patients and is mediated by mechanical, inflammatory, and metabolic mechanisms. Obesity and the associated conditions (hyperglycemia, dyslipidemia, and hypertension) have been found to be risk factors for the development of knee OA, which has led to the emerging concept of the existence of a distinct phenotype, i.e., metabolic knee OA. Combined assessment of markers derived from dysfunctional adipose tissue, markers of bone and cartilage metabolism, as well as high-sensitivity inflammatory markers and imaging, might reveal prognostic signs for metabolic knee OA. Interestingly, it has been suggested that drugs used for the treatment of other components of the metabolic syndrome may also affect the clinical course and retard the progression of metabolic-associated knee OA. In this regard, significant amounts of new data are accumulating about the role of metformin-a drug, commonly used in clinical practice with suggested multiple pleiotropic effects. The aim of the current review is to analyze the current views about the potential pleiotropic effects of metformin in OA. Upon the analysis of the different effects of metformin, major mechanisms that might be involved in OA are the influence of inflammation, oxidative stress, autophagy, adipokine levels, and microbiome modulation. There is an increasing amount of evidence from in vitro studies, animal models, and clinical trials that metformin can slow OA progression by modulating inflammatory and metabolic factors that are summarized in the current up-to-date review. Considering the contemporary concept about the existence of metabolic type knee OA, in which the accompanying obesity and systemic low-grade inflammation are suggested to influence disease course, metformin could be considered as a useful and safe component of the personalized therapeutic approach in knee OA patients with accompanying type II diabetes or obesity.

Glucose and lipopolysaccharide differentially regulate fibroblast growth factor 21 in healthy male human volunteers - A prospective cross-over trial

Fibroblast growth factor 21 (FGF21) affects the regulation of metabolism. Additionally, anti-inflammatory properties are attributed to FGF21, and studies in animals and humans show conflicting results. This study aimed to investigate how FGF21 is affected by glucose and lipopolysaccharide (LPS) in humans. Therefore, FGF21 was measured eight times at different time points within 48 h in this prospective cross-over trial after glucose and LPS on two different study days. The study included ten healthy, non-smoking male subjects aged 18-40. Repeated measures analysis of variance and paired t-test as post hoc analysis were applied. The administration of glucose and LPS resulted in a significant difference in regulating FGF21 (p < 0.001). After glucose administration, FGF21 declined sharply at 360 min, with a subsequent steep increase that exceeded baseline levels. LPS induced a drop in FGF21 after 180 min, while the baseline concentrations were not reached. After 180 min and 24 h, a statistically significant difference was demonstrated after adjusting the Bonferroni-Holm method. So, our results support the hypothesis that glucose and LPS differentially affect the human expression of FGF21 over 48 h.

Effectiveness of Moringa oleifera Leaves on TNF-α Expression, Insulin Levels, Glucose Levels and Follicle Count in Rattus norvegicus PCOS Model

BACKGROUND

Polycystic ovary syndrome (PCOS) is a syndrome characterized by ovulation disorders accompanied by hyperandrogens. Women with PCOS are prone to develop insulin resistance which has metabolic characteristics similar to type 2 diabetes and leads to disturbance of follicular formation. PCOS is also known to increase the concentration of proinflammatory cytokines, namely TNF-α. Moringa oleifera leaves have been shown to have compounds that can reduce insulin levels and glucose levels in diabetes mellitus and should be able to reduce TNF-α and follicle count.

PURPOSE

This study aims to prove the effectiveness of Moringa oleifera leaf in reducing insulin, glucose levels, TNF-α and follicle count in PCOS.

METHODS

The three-month-old white rats Wistar (Rattus norvegicus) 150-170 grams were divided into four groups (n = 10), namely normal rats, PCOS model rats, PCOS model rats given metformin, and PCOS rats given 500mg of Moringa oleifera. The method of this study is taking PCOS model rats by injecting the 100mg/kg BW hormone testosterone propionate for 21 days. After 21 days of therapy, we analyzed insulin, glucose levels, TNF-α and follicle count.

RESULTS

The PCOS control group showed an increase in insulin level, glucose levels, TNF-α expression, and a decrease in the follicle count compared to the normal control group. The insulin level, glucose level, TNF-α and follicle count in the Moringa oleifera 500 mg/kg BW treatment group were significantly lower than in the PCOS control group.

CONCLUSION

Moringa oleifera leaves have the potential in reducing insulin levels, blood glucose levels, TNF-α and follicle count in PCOS patients.

Enhanced lipid metabolism confers the immunosuppressive tumor microenvironment in CD5-positive non-MYC/BCL2 double expressor lymphoma

Lymphoma cells expressing CD5 (CD5+) confer inferior outcome of diffuse large B-cell lymphoma (DLBCL), especially in non–MYC/BCL2 double expressor (non-DE) patients. In tumor microenvironment, CD5+ non-DE tumor revealed increased proportion of immunosuppressive M2 macrophages and enhanced pathways related to macrophage activation and migration. In accordance to M2 activation, lipid metabolism was upregulated, including fatty acid uptake and fatty acid oxidation, which supplied energy for M2 macrophage polarization and activation. Meanwhile, CD36 expression was upregulated and strongly correlated to the proportion of M2 macrophages in CD5+ non-DE DLBCL. In vitro, a DLBCL cell line (LY10) overexpressing CD5 significantly increased M2 proportion in comparison with control when cocultured with peripheral blood mononuclear cells (PBMCs). The addition of metformin significantly decreased the M2 proportion and the CD36 expression level in the coculture systems, indicating that metformin could target altered lipid metabolism and decrease M2 macrophages in DLBCL, especially in CD5+ non-DE lymphoma. In conclusion, enhanced lipid metabolism and M2 macrophage activation contributed to the immunosuppressive tumor microenvironment and could be potential therapeutic targets in CD5+ non-DE DLBCL.

Increased susceptibility to pneumonia due to tumour necrosis factor inhibition and prospective immune system rescue via immunotherapy

Immunomodulators such as tumour necrosis factor (TNF) inhibitors are used to treat autoimmune conditions by reducing the magnitude of the innate immune response. Dampened innate responses pose an increased risk of new infections by opportunistic pathogens and reactivation of pre-existing latent infections. The alteration in immune response predisposes to increased severity of infections. TNF inhibitors are used to treat autoimmune conditions such as rheumatoid arthritis, juvenile arthritis, psoriatic arthritis, transplant recipients, and inflammatory bowel disease. The efficacies of immunomodulators are shown to be varied, even among those that target the same pathways. Monoclonal antibody-based TNF inhibitors have been shown to induce stronger immunosuppression when compared to their receptor-based counterparts. The variability in activity also translates to differences in risk for infection, moreover, parallel, or sequential use of immunosuppressive drugs and corticosteroids makes it difficult to accurately attribute the risk of infection to a single immunomodulatory drug. Among recipients of TNF inhibitors, Mycobacterium tuberculosis has been shown to be responsible for 12.5-59% of all infections; Pneumocystis jirovecii has been responsible for 20% of all non-viral infections; and Legionella pneumophila infections occur at 13-21 times the rate of the general population. This review will outline the mechanism of immune modulation caused by TNF inhibitors and how they predispose to infection with a focus on Mycobacterium tuberculosis, Legionella pneumophila, and Pneumocystis jirovecii. This review will then explore and evaluate how other immunomodulators and host-directed treatments influence these infections and the severity of the resulting infection to mitigate or treat TNF inhibitor-associated infections alongside antibiotics.

Effects and safety of metformin in patients with concurrent diabetes mellitus and chronic obstructive pulmonary disease: a systematic review and meta-analysis

Aim

This study aimed to investigate the effects and safety of metformin in patients with concurrent diabetes mellitus (DM) and chronic obstructive pulmonary disease (COPD).

Methods

PubMed, Embase, Web of Science, the China National Knowledge, and Cochrane Database were searched to find studies that examined the effects and safety of metformin in patients with concurrent DM and COPD. We conducted a meta-analysis with a risk ratio (RR) and assessed the quality of included studies and pooled evidence.

Results

Eight studies were involved. Metformin was associated with lower risk of COPD-related hospitalizations (RR: 0.72, 95% CI: 0.53-0.98; I2= 89%) and all-cause mortality (RR: 0.60, 95% CI: 0.36-1.01, I2= 69%) in patients with concurrent DM and COPD, but did not increase the risk of hyperlactatemia (RR: 1.14, 95% CI: 0.92-1.41, I2 = 8%).

Conclusions

Metformin use is associated with lower risk of COPD-related hospitalizations and risk of all-cause mortality without increasing the risk of hyperlactatemia. Considerations should be given to conduct more high-quality randomized trials involving larger samples.

Investigation into the anti-inflammatory properties of metformin in intervertebral disc cells

Introduction

Intervertebral disc degeneration (IDD) is closely related to heightened inflammation in the annulus fibrosis (AF) and nucleus pulposus (NP) cells in the intervertebral disc. An imbalanced matrix homeostasis has been shown to contribute to disc degeneration and associated discogenic low back pain. Metformin, a diabetes medication, has been noted to exhibit anti-inflammatory properties through upregulation of the AMPK pathway, leading to various anti-inflammatory-related responses in hepatocytes. However, it is still unclear how metformin influences disc cellular response to inflammatory stress and the corresponding mechanism. Hence, the objective of this study is to elucidate the effects of metformin on expression of key pro-inflammatory, catabolic, and anabolic factors within rat AF cells in response to inflammatory stimulation and mechanical tensile stress.

Methods

Five Fischer 344 rats were sacrificed and their spines isolated. AF cells were cultured and plated in flexible silicone membrane-based six-well plates. Wells were split into eight groups and subjected to metformin, IL-1β, mechanical stretch, and combined treatments. Relative gene expressions of MMP-13, COX-2, iNOS, AGC, and Col1 were assessed with quantitative real-time polymerase chain reaction (qRT-PCR), and downstream prostaglandin E2 (PGE2) production was quantified with enzyme-linked immunosorbent assay (ELISA). NF-kB nuclear translocation was also quantified.

Results

Metformin in the presence of the combined stress treatments (M + IL/S) significantly increased Col1, COX-2, and MMP-13 gene expression, decreased PGE2 production compared to IL/S conditions alone. Metformin treatment of cultured rat annulus fibrosus cells significantly reduced the nuclear translocation of NF-κB after 4 h of IL-1β treatment from 43.1% in case of IL-1β treatment down to 26.2% in the case of metformin + IL-1β treatment.

Discussion

The lack of metformin-mediated suppression of inflammatory response in the nonstretch groups indicates that metformin may be enacting its effects through a stretch-dependent manner. These results suggest a foundation for pursuing further research into metformin's potential role as an anti-inflammatory agent for curtailing intervertebral disc degeneration.

Current Strategies in Treating Cytokine Release Syndrome Triggered by Coronavirus SARS-CoV-2

Since the beginning of the SARS-CoV-2 pandemic, the treatments and management of the deadly COVID-19 disease have made great progress. The strategies for developing novel treatments against COVID-19 include antiviral small molecule drugs, cell and gene therapies, immunomodulators, neutralizing antibodies, and combination therapies. Among them, immunomodulators are the most studied treatments. The small molecule antiviral drugs and immunoregulators are expected to be effective against viral variants of SARS-CoV-2 as these drugs target either conservative parts of the virus or common pathways of inflammation. Although the immunoregulators have shown benefits in reducing mortality of cytokine release syndrome (CRS) triggered by SARS-CoV-2 infections, extensive investigations on this class of treatment to launch novel therapies that substantially improve efficacy and reduce side effects are still warranted. Moreover, great challenges have emerged as the SARS-CoV-2 virus quickly, frequently, and continuously evolved. This review provides an update and summarizes the recent advances in the treatment of COVID-19 and in particular emphasized the strategies in managing CRS triggered by SARS-CoV-2. A brief perspective in the battle against the deadly disease was also provided.

Metformin Alleviates Airway Hyperresponsiveness in a Mouse Model of Diet-Induced Obesity

Obese asthma is a unique phenotype of asthma characterized by non-allergic airway hyperresponsiveness (AHR) and inflammation which responds poorly to standard asthma therapy. Metformin is an oral hypoglycemic drug with insulin-sensitizing and anti-inflammatory properties. The objective of the current study was to test the effect of metformin on AHR in a mouse model of diet-induced obesity (DIO). We fed 12-week-old C57BL/6J DIO mice with a high fat diet for 8 weeks and treated them with either placebo (control, n = 10) or metformin (n = 10) added in drinking water (300 mg/kg/day) during the last 2 weeks of the experiment. We assessed AHR, metabolic profiles, and inflammatory markers after treatments. Metformin did not affect body weight or fasting blood glucose, but significantly reduced serum insulin (p = 0.0117). Metformin reduced AHR at 30 mg/ml of methacholine challenge (p = 0.0052) without affecting baseline airway resistance. Metformin did not affect circulating white blood cell counts or lung cytokine mRNA expression, but modestly decreased circulating platelet count. We conclude that metformin alleviated AHR in DIO mice. This finding suggests metformin has the potential to become an adjuvant pharmacological therapy in obese asthma.

An Objective Diagnosis Model with Integrated Metabolic and Immunity Parameters for Phlegm-Dampness Constitution

BACKGROUND

According to Chinese constitutional theory, people can be divided into nine constitutions, which represent distinctive vulnerability to different diseases such as metabolic syndrome, atherosclerosis, and immunity-related disease, and so forth in modern medicine, phlegm-dampness constitution (PDC) is one of the nine constitutions, which is susceptible to metabolic syndrome (MS) and atherosclerosis that associate with lipid metabolism and immunity dysregulation closely.

OBJECTIVES

In this study, we aimed to investigate the metabolic and immunity profiles of phlegm-damp constitution (PDC), including metabolites, lymphocytes distribution, and inflammatory cytokines.

METHODS

A total of 74 patients with PDC and 66 individuals with gentle constitution (GC) were enrolled in this study. We utilized biochemical methods to detect metabolic parameters, flow cytometry to survey T/B/NK/NKT lymphocyte subgroups distribution, and ELISA to assay inflammatory cytokines.

RESULTS

The subjects with PDC had higher GLU, AI TC, TG, and LDL-C and lower HDL-C levels. The immunity profile indicated that PDC subjects had higher percentage of WBCs, neutrophils, lymphocytes, B cells, and natural killer T cells compared with subjects with GC (P < 0.05). Serum levels of IL-10 decreased significantly in the subjects with phlegm-damp constitution, whereas IL-12 levels increased dramatically in the PDC group compared with the GC group (both P < 0.05). Additionally, logistic regression identified four independent variables (GLU, TG, LDL-C, and lymphocytes) that were highly correlated with PDC (P < 0.05). The area under the curve of the receiver operating characteristic curve was 0.878, which indicated the data were reliable to distinguish the subjects with PDC from the ones with GC.

CONCLUSION

Phlegm-damp constitution was prone to hyperglycemia and hyperlipidemia syndrome, promoting the occurrence and progression of metabolic-related diseases. Interestingly, proinflammatory cells and cytokines were activated in the PDC group as well. Our findings could offer a profile of early screening indicators to identify high-risk patients of metabolic- and immunity-related diseases from Chinese constitution.

Association Between Metformin Use and Mortality among Patients with Type 2 Diabetes Mellitus Hospitalized for COVID-19 Infection

Introduction

Metformin has known mechanistic benefits on COVID-19 infection due to its anti-inflammatory effects and its action on the ACE2 receptor. However, some physicians are reluctant to use it in hypoxemic patients due to potential lactic acidosis. The primary purpose of the study was to determine whether metformin use is associated with survival. We also wanted to determine whether there is a difference in outcomes in subcategories of metformin use, whether at home, in-hospital, or mixed home/in-hospital use.

Objectives

This study aimed to determine an association between metformin use and mortality among patients with type 2 diabetes mellitus hospitalized for COVID-19 infection.

Methodology

This was a cross-sectional analysis of data acquired from the COVID-19 database of two tertiary hospitals in Cebu from March 1, 2020, to September 30, 2020. Hospitalized adult Filipino patients with type 2 diabetes mellitus who tested positive for COVID-19 via RT-PCR were included and categorized as either metformin users or metformin non-users.

Results

We included 355 patients with type 2 diabetes mellitus in the study, 186 (52.4%) were metformin users. They were further categorized into home metformin users (n=109, 30.7%), in-hospital metformin users (n=40, 11.3%), and mixed home/in-hospital metformin users (n=37, 10.4%). Metformin use was associated with a lower risk for mortality compared to non-users (p=0.001; OR=0.424). In-hospital and mixed home/in-hospital metformin users were associated with lower mortality odds than non-users (p=0.002; OR=0.103 and p=0.005; OR 0.173, respectively). The lower risk for mortality was noted in metformin, regardless of dosage, from 500 mg to 2 g daily (p=0.002). Daily dose between ≥1000 mg to <2000 mg was associated with the greatest benefit on mortality (p≤0.001; OR=0.252). The survival distributions between metformin users and non-users were statistically different, showing inequality in survival (χ2=5.67, p=0.017).

Conclusion

Metformin was associated with a lower risk for mortality in persons with type 2 diabetes mellitus hospitalized for COVID-19 disease compared to non-users. Use of metformin in-hospital, and mixed home/in-hospital metformin use, was also associated with decreased risk for mortality. The greatest benefit seen was in those taking a daily dose of ≥1000 mg to <2000 mg.

Effects of Probiotic Supplementation on Inflammatory Markers and Glucose Homeostasis in Adults With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background: Several studies have revealed the effect of probiotic supplementation in patients with type 2 diabetes (T2DM) on the amelioration of low-grade inflammation, which plays an important role in the pathogenesis of T2DM. However, the effects of the clinical application of probiotics on inflammation in individuals with T2DM remain inconsistent. This study aims to investigate the comprehensive effects of probiotics on inflammatory markers in adults with T2DM.

Methods: PubMed, Embase, Cochrane Library, and the Web of Science were searched to identify randomized controlled trials (RCTs) exploring the effect of probiotic supplementation on inflammatory markers in individuals with T2DM through March 11, 2021. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. We used a random-effects model to calculate the standardized mean difference (SMD) between the probiotic supplementation and control groups.

Results: Seventeen eligible studies were selected with a total of 836 participants, including 423 participants in probiotic supplementation groups and 413 participants in control groups. Our study demonstrated that compared with the control condition, probiotic intake produced a beneficial effect in reducing the levels of plasma inflammation markers, including tumour necrosis factor-α (TNF-α) (SMD [95% CI]; −0.37 [−0.56, −0.19], p < 0.0001) and C-reactive protein (CRP) (SMD [95% CI]; −0.21 [−0.42, −0.01], p = 0.040), while it had no effect on the plasma interleukin-6 (IL-6) level (SMD [95% CI]; −0.07 [−0.27, 0.13], p = 0.520). In addition, our results support the notion that probiotic supplementation improves glycaemic control, as evidenced by a significant reduction in fasting blood glucose (FPG), HbA1c and HOMA-IR (SMD [95% CI]: −0.24 [−0.42, −0.05], p = 0.010; −0.19 [−0.37, −0.00], p = 0.040; −0.36 [−0.62, −0.10], p = 0.006, respectively).

Conclusion: Our study revealed some beneficial effects of probiotic supplementation on improving inflammatory markers and glucose homeostasis in individuals with T2DM. Probiotics might be a potential adjuvant therapeutic approach for T2DM.

Antidiabetic drugs and oxidized low-density lipoprotein: A review of anti-atherosclerotic mechanisms

Cardiovascular disease is one of the leading causes of mortality globally. Atherosclerosis is an important step towards different types of cardiovascular disease. The role of oxidized low-density lipoprotein (oxLDL) in the initiation and progression of atherosclerosis has been thoroughly investigated in recent years. Moreover, clinical trials have established that diabetic patients are at a greater risk of developing atherosclerotic plaques. Hence, we aimed to review the clinical and experimental impacts of various classes of antidiabetic drugs on the circulating levels of oxLDL. Metformin, pioglitazone, and dipeptidyl peptidase-4 inhibitors were clinically associated with a suppressive effect on oxLDL in patients with impaired glucose tolerance. However, there is an insufficient number of studies that have clinically evaluated the relationship between oxLDL and newer agents such as agonists of glucagon-like peptide 1 receptor or inhibitors of sodium-glucose transport protein 2. Next, we attempted to explore the multitude of mechanisms that antidiabetic agents exert to counter the undesirable effects of oxLDL in macrophages, endothelial cells, and vascular smooth muscle cells. In general, antidiabetic drugs decrease the uptake of oxLDL by vascular cells and reduce subsequent inflammatory signaling, which prevents macrophage adhesion and infiltration. Moreover, these agents suppress the oxLDL-induced transformation of macrophages into foam cells by either inhibiting oxLDL entrance, or by facilitating its efflux. Thus, the anti-inflammatory, anti-oxidant, and anti-apoptotic properties of antidiabetic agents abrogate changes induced by oxLDL, which can be extremely beneficial in controlling atherosclerosis in diabetic patients.

The cumulative dose-dependent effects of metformin on the development of tuberculosis in patients newly diagnosed with type 2 diabetes mellitus

BACKGROUND

Diabetes mellitus (DM) is a well-known risk factor for tuberculosis (TB). Metformin, which is an essential anti-diabetic drug, has been shown to exhibit anti-TB effects in patients with DM. Its effect on preventing the development of TB among patients who are newly diagnosed with DM remains unclear.

METHODS

This was a retrospective cohort study using the claims database of the Korean Health Insurance Review and Assessment Service. The study population included patients who were newly diagnosed with type 2 DM and who were treated with anti-diabetic drugs between 1 January 2003 and 31 March 2011. A patient was defined as a metformin user if he/she had taken metformin for more than 28 days within 6 months since cohort entry, and as a metformin non-user if he/she had never been treated with metformin. The development of TB within 2 years after the index date was compared by Cox proportional hazard regression models between metformin users and 1:1 propensity score (PS)-matched non-users.

RESULTS

Among 76,973 patients who were newly diagnosed with type 2 DM, 13,396 were classified as metformin users, 52,736 were classified as metformin non-users, and 10,841 were excluded from the final analysis. PS-matched Cox proportional hazard regression models revealed that metformin use was not associated overall with the prevention of TB development (HR 1.17; 95% CI 0.75-1.83; P = 0.482). There was a trend, however, towards a reduction in the development of TB among patients taking a higher cumulative dose of metformin. Patients who were in the highest quartile (Q4) of cumulative metformin dose had only a 10% risk of developing TB compared to metformin non-users. In contrast, during the early phases of metformin treatment, patients in the second quartile (Q2) of cumulative metformin use had a higher risk of developing TB than patients in the first quartile (Q1).

CONCLUSIONS

Only the highest cumulative doses of metformin were protective against the development of TB among patients who were newly diagnosed with type 2 DM; lower cumulative doses of metformin did not appear to reduce the incidence of active TB infection.

Metformin attenuates silica-induced pulmonary fibrosis via AMPK signaling

Background

Silicosis is one of the most common occupational pulmonary fibrosis caused by respirable silica-based particle exposure, with no ideal drugs at present. Metformin, a commonly used biguanide antidiabetic agent, could activate AMP-activated protein kinase (AMPK) to exert its pharmacological action. Therefore, we sought to investigate the role of metformin in silica-induced lung fibrosis.

Methods

The anti-fibrotic role of metformin was assessed in 50 mg/kg silica-induced lung fibrosis model. Silicon dioxide (SiO₂)-stimulated lung epithelial cells/macrophages and transforming growth factor-beta 1 (TGF-β1)-induced differentiated lung fibroblasts were used for in vitro models.

Results

At the concentration of 300 mg/kg in the mouse model, metformin significantly reduced lung inflammation and fibrosis in SiO₂-instilled mice at the early and late fibrotic stages. Besides, metformin (range 2–10 mM) reversed SiO₂-induced cell toxicity, oxidative stress, and epithelial-mesenchymal transition process in epithelial cells (A549 and HBE), inhibited inflammation response in macrophages (THP-1), and alleviated TGF-β1-stimulated fibroblast activation in lung fibroblasts (MRC-5) via an AMPK-dependent pathway.

Conclusions

In this study, we identified that metformin might be a potential drug for silicosis treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03036-5.

A Metabolic Pattern in Healthy Subjects Given a Single Dose of Metformin: A Metabolomics Approach

Metformin is a widely prescribed medication for the treatment of type 2 diabetes mellitus (T2DM). It possesses effective roles in various disorders, including cancer, dyslipidemia, and obesity. However, the underlying mechanisms of metformin's multiple benefits are not fully understood. Herein, a mass spectrometry-based untargeted metabolomics approach was used to investigate the metabolic changes associated with the administration of a single dose of metformin in the plasma of 26 healthy subjects at five-time points; pre-dose, before the maximum concentration of metformin (C_max), C_max, after C_max, and 36 h post-dose. A total of 111 metabolites involved in various biochemical processes were perturbed, with branched-chain amino acid (BCAA) being the most significantly altered pathway. Additionally, the Pearson similarity test revealed that 63 metabolites showed a change in their levels dependent on metformin level. Out of these 63, the level of 36 metabolites was significantly altered by metformin. Significantly altered metformin-dependent metabolites, including hydroxymethyl uracil, propionic acid, glycerophospholipids, and eicosanoids, pointed to fundamental biochemical processes such as lipid network signaling, energy homeostasis, DNA lesion repair mechanisms, and gut microbiota functions that could be linked to the multiple beneficial roles of metformin. Thus, the distinctive metabolic pattern linked to metformin administration can be used as a metabolic signature to predict the potential effect and mechanism of actions of new chemical entities during drug development.

Outpatient metformin use is associated with reduced severity of COVID-19 disease in adults with overweight or obesity

Observational studies suggest outpatient metformin use is associated with reduced mortality from coronavirus disease-2019 (COVID-19). Metformin is known to decrease interleukin-6 and tumor-necrosis factor-α, which appear to contribute to morbidity in COVID-19. We sought to understand whether outpatient metformin use was associated with reduced odds of severe COVID-19 disease in a large US healthcare data set. Retrospective cohort analysis of electronic health record (EHR) data that was pooled across multiple EHR systems from 12 hospitals and 60 primary care clinics in the Midwest between March 4, 2020 and December 4, 2020. Inclusion criteria: data for body mass index (BMI) > 25 kg/m2 and a positive SARS-CoV-2 polymerase chain reaction test; age ≥ 30 and ≤85 years. Exclusion criteria: patient opt-out of research. Metformin is the exposure of interest, and death, admission, and intensive care unit admission are the outcomes of interest. Metformin was associated with a decrease in mortality from COVID-19, OR 0.32 (0.15, 0.66; p = .002), and in the propensity-matched cohorts, OR 0.38 (0.16, 0.91; p = .030). Metformin was associated with a nonsignificant decrease in hospital admission for COVID-19 in the overall cohort, OR 0.78 (0.58-1.04, p = .087). Among the subgroup with a hemoglobin HbA1c available (n = 1193), the adjusted odds of hospitalization (including adjustment for HbA1c) for metformin users was OR 0.75 (0.53-1.06, p = .105). Outpatient metformin use was associated with lower mortality and a trend towards decreased admission for COVID-19. Given metformin's low cost, established safety, and the mounting evidence of reduced severity of COVID-19 disease, metformin should be prospectively assessed for outpatient treatment of COVID-19.

Prevention of Hypertensive Disorders of Pregnancy-Is There a Place for Metformin?

The possibility of prophylaxis of hypertensive disorders of pregnancy (HDPs) such as preeclampsia (PE) and pregnancy-induced hypertension is of interest due to the unpredictable course of these diseases and the risks they carry for both mother and fetus. It has been proven that their development is associated with the presence of the placenta, and the processes that initiate it begin at the time of the abnormal invasion of the trophoblast in early pregnancy. The ideal HDP prophylaxis should alleviate the influence of risk factors and, at the same time, promote physiological trophoblast invasion and maintain the physiologic endothelium function without any harm to both mother and fetus. So far, aspirin is the only effective and recommended pharmacological agent for the prevention of HDPs in high-risk groups. Metformin is a hypoglycemic drug with a proven protective effect on the cardiovascular system. Respecting the anti-inflammatory properties of metformin and its favorable impact on the endothelium, it seems to be an interesting option for HDP prophylaxis. The results of previous studies on such use of metformin are ambiguous, although they indicate that in a certain group of pregnant women, it might be effective in preventing hypertensive complications. The aim of this study is to present the possibility of metformin in the prevention of hypertensive disorders of pregnancy with respect to its impact on the pathogenic elements of development

Advanced glycation end products and their receptors in serum of patients with type 2 diabetes

Glycation is a non-enzymatic process involving the reaction of reducing sugars or reactive oxoaldehyde with proteins, lipids or nucleic acids, which results in the formation of advanced glycation end products (AGEs). The presented work discusses the glycation process in people with advanced stage of type 1 or type 2 diabetes. The concentration of different AGEs and their receptors for 58 serum samples was determined by ELISA and by spectrofluorimetric methods. In addition to fluorescent low molecular weight and protein-bound AGEs, we have also marked a new class of AGEs: melibiose-derived glycation product (MAGE). Our attention was also focused on the two groups of AGEs receptors: scavenger receptors (SR-A and SR-B) and RAGE. The correlation between the SR-AI scavenging receptors concentration and the fluorescence of AGEs as well as diabetes biological markers: GFR, creatinine contentration and HbA1c was demonstrated. A relationship between the concentration of AGEs and their receptors was also found in serum sample of patients treated with the metformin and aspirin. Furthermore, the concentration of SR-AI scavenger and the fluorescence of total AGEs was significantly lower in treated patients than in non treated patients. AGEs have also been found to contribute to the development of cardiovascular disease, atherosclerosis and diabetic complications, what could be deduced from the correlation of AGEs level and HDL cholesterol or uric acid level. Thus, it was confirmed that AGEs are involved in the pathomechanism of diabetes and other degenerative diseases. Nowadays, it is believed that AGEs due to the long time remaining in the body may be an important diagnostic marker. Their determination may allow monitoring the progression of the disease and the effectiveness of the therapy.

Metformin and Vitamin D Modulate Inflammation and Autophagy during Adipose-Derived Stem Cell Differentiation

Adipose-derived stem cells (ADSCs) came out from the regenerative medicine landscape for their ability to differentiate into several phenotypes, contributing to tissue regeneration both in vitro and in vivo. Dysregulation in stem cell recruitment and differentiation during adipogenesis is linked to a chronic low-grade inflammation and macrophage infiltration inside the adipose tissue, insulin resistance, cardiovascular disease and obesity. In the present paper we aimed to evaluate the role of metformin and vitamin D, alone or in combination, in modulating inflammation and autophagy in ADSCs during adipogenic commitment. ADSCs were cultured for 21 days in the presence of a specific adipogenic differentiation medium, together with metformin, or vitamin D, or both. We then analyzed the expression of FoxO1 and Heat Shock Proteins (HSP) and the secretion of proinflammatory cytokines IL-6 and TNF-α by ELISA. Autophagy was also assessed by specific Western blot analysis of ATG12, LC3B I, and LC3B II expression. Our results showed the ability of the conditioned media to modulate adipogenic differentiation, finely tuning the inflammatory response and autophagy. We observed a modulation in HSP mRNA levels, and a significant downregulation in cytokine secretion. Taken together, our findings suggest the possible application of these molecules in clinical practice to counteract uncontrolled lipogenesis and prevent obesity and obesity-related metabolic disorders.

Effects of metformin on lipopolysaccharide induced inflammation by activating fibroblast growth factor 21

Lipopolysaccharide (LPS) is a component of the cell wall of Gram-negative bacteria that produces endotoxemia, which may cause septic shock. Metformin (MET) is a widely used hypoglycemic drug that exhibits anti-inflammatory properties. Fibroblast growth factor 21 (FGF21) is an endocrine polypeptide that affects glucose and lipid metabolism, and also possesses anti-inflammatory properties. We investigated the effects of MET and FGF21 on inflammation due to LPS induced endotoxemia in male rats. Animals were divided into five groups: control, LPS, pre-MET LPS, LPS + 1 h MET and LPS + 3 h MET. Serum levels of alanine aminotransferase, aspartate aminotransferase, FGF2, interleukin-10 and tumor necrosis factor alpha were measured. Malondialdehyde, myeloperoxidase and FGF21 levels were measured in liver tissue samples. Histopathology of all groups was assessed using hematoxylin and eosin stained sections. LPS caused severe inflammatory liver damage. MET exhibited a partially protective effect and reduced inflammation significantly. FGF21 is produced in the liver following inflammation and MET may increase its production.

Association of metformin with mortality or ARDS in patients with COVID-19 and type 2 diabetes: A retrospective cohort study

AIMS

To determine the association between metformin use and mortality and ARDS incidence in patients with COVID-19 and type 2 diabetes.

METHODS

This study was a multi-center retrospective analysis of COVID-19 patients with type 2 diabetes and admitted to four hospitals in Hubei province, China from December 31st, 2019 to March 31st, 2020. Patients were divided into two groups according to their exposure to metformin during hospitalization. The outcomes of interest were 30-day all-cause mortality and incidence of ARDS. We used mixed-effect Cox model and random effect logistic regression to evaluate the associations of metformin use with outcomes, adjusted for baseline characteristics.

RESULTS

Of 328 patients with COVID-19 and type 2 diabetes included in the study cohort, 30.5% (100/328) were in the metformin group. In the mixed-effected model, metformin use was associated with the lower incidence of ARDS. There was no significant association between metformin use and 30-day all-cause mortality. Propensity score-matched analysis confirmed the results. In the subgroup analysis, metformin use was associated with the lower incidence of ARDS in females.

CONCLUSIONS

Metformin may have potential benefits in reducing the incidence of ARDS in patients with COVID-19 and type 2 diabetes. However, this benefit differs significantly by gender.