Anti-inflammatory mechanism of metformin and its effects in intestinal inflammation and colitis-associated colon cancer

The role of ZEB1 in mediating the protective effects of metformin on skeletal muscle atrophy

Metformin is an important antidiabetic drug that has the potential to reduce skeletal muscle atrophy and promote the differentiation of muscle cells. However, the exact molecular mechanism underlying these functions remains unclear. Previous studies revealed that the transcription factor zinc finger E-box-binding homeobox 1 (ZEB1), which participates in tumor progression, inhibits muscle atrophy. Therefore, we hypothesized that the protective effect of metformin might be related to ZEB1. We investigated the positive effect of metformin on IL-1β-induced skeletal muscle atrophy by regulating ZEB1 in vitro and in vivo. Compared with the normal cell differentiation group, the metformin-treated group presented increased myotube diameters and reduced expression levels of atrophy-marker proteins. Moreover, muscle cell differentiation was hindered, when we artificially interfered with ZEB1 expression in mouse skeletal myoblast (C2C12) cells via ZEB1-specific small interfering RNA (si-ZEB1). In response to inflammatory stimulation, metformin treatment increased the expression levels of ZEB1 and three differentiation proteins, MHC, MyoD, and myogenin, whereas si-ZEB1 partially counteracted these effects. Moreover, marked atrophy was induced in a mouse model via the administration of lipopolysaccharide (LPS) to the skeletal muscles of the lower limbs. Over a 4-week period of intragastric administration, metformin treatment ameliorated muscle atrophy and increased the expression levels of ZEB1. Metformin treatment partially alleviated muscle atrophy and stimulated differentiation. Overall, our findings may provide a better understanding of the mechanism underlying the effects of metformin treatment on skeletal muscle atrophy and suggest the potential of metformin as a therapeutic drug.

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.

Melinjo (Gnetum gnemon L) Extract Attenuates Colonic Inflammation in a Mouse Colitis Model by Regulating the AMPK/NFκB/Sirt1 Pathway

Ulcerative colitis (UC) is a subtype of inflammatory bowel disease affecting the colon with idiopathic origin. Melinjo endosperm extract (MeE) contains polyphenolic compounds that have antioxidative and anticancer properties. We examined the effect of MeE on inflammation and mucin expression in the colons of UC of mice treated with dextran sulfate sodium (DSS). C57BL/6J male mice were assigned into four categories: control, DSS + 0% MeE, DSS + 0.1% MeE, and DSS + 0.5% MeE. The control group was provided distilled water and a standard chow diet for 4 weeks. In DSS + 0% MeE, DSS + 0.1% MeE, and DSS + 0.5% MeE groups, the mice were treated with MeE for 3 weeks followed by MeE diets and drinking water containing 3% DSS for a week. Macrophage count, the mucus area stained by Alcian blue (AB), the levels of adenosine monophosphate-activated protein kinase (AMPK), nuclear factor-κB (NFκB) p65, and silent information regulator (Sirt) 1 protein expression, as well as proinflammatory mediators and Mucin 2 mRNA expression were assessed. In the DSS + 0% MeE group, the AB-stained areas and Mucin 2 mRNA expression levels were observed to be lower than those of controls. However, the levels in the +0.5% MeE group were significantly increased. Compared with the control group, the macrophage number, the expression of IL-1β mRNA, and NFκB p65 protein in the DSS + 0% MeE group showed a significant increase. Conversely, these levels were significantly decreased in the +0.5% MeE group. The phosphorylated AMPK and Sirt1 protein levels were upregulated in the +0.5% MeE group. In conclusion, MeE may alleviate UC injury by reducing macrophage infiltration and regulating the AMPK/NFκB/Sirt1 pathway.

AMPK Deficiency Increases DNA Methylation and Aggravates Colorectal Tumorigenesis in AOM/DSS Mice

The incidence of colorectal cancer (CRC) is closely linked to metabolic diseases. Accumulating evidence suggests the regulatory role of AMP-activated protein kinase (AMPK) in cancer metabolic reprogramming. In this study, wild-type and AMPK knockout mice were subjected to azoxymethane-induced and dextran sulfate sodium (AOM/DSS)-promoted colitis-associated CRC induction. A stable AMPK-deficient Caco-2 cell line was also established for the mechanistic studies. The data showed that AMPK deficiency accelerated CRC development, characterized by increased tumor number, tumor size, and hyperplasia in AOM/DSS-treated mice. The aggravated colorectal tumorigenesis resulting from AMPK ablation was associated with reduced α-ketoglutarate production and ten-eleven translocation hydroxylase 2 (TET2) transcription, correlated with the reduced mismatch repair protein mutL homolog 1 (MLH1) protein. Furthermore, in AMPK-deficient Caco-2 cells, the mRNA expression of mismatch repair and tumor suppressor genes, intracellular α-ketoglutarate, and the protein level of TET2 were also downregulated. AMPK deficiency also increased hypermethylation in the CpG islands of Mlh1 in both colonic tissues and Caco-2 cells. In conclusion, AMPK deficiency leads to reduced α-ketoglutarate concentration and elevates the suppressive epigenetic modifications of tumor suppressor genes in gut epithelial cells, thereby increasing the risk of colorectal tumorigenesis. Given the modifiable nature of AMPK activity, it holds promise as a prospective molecular target for the prevention and treatment of CRC.

Anti-Inflammatory Potential of the Anti-Diabetic Drug Metformin in the Prevention of Inflammatory Complications and Infectious Diseases Including COVID-19: A Narrative Review

Metformin, a widely used first-line anti-diabetic therapy for the treatment of type-2 diabetes, has been shown to lower hyperglycemia levels in the blood by enhancing insulin actions. For several decades this drug has been used globally to successfully control hyperglycemia. Lactic acidosis has been shown to be a major adverse effect of metformin in some type-2 diabetic patients, but several studies suggest that it is a typically well-tolerated and safe drug in most patients. Further, recent studies also indicate its potential to reduce the symptoms associated with various inflammatory complications and infectious diseases including coronavirus disease 2019 (COVID-19). These studies suggest that besides diabetes, metformin could be used as an adjuvant drug to control inflammatory and infectious diseases. In this article, we discuss the current understanding of the role of the anti-diabetic drug metformin in the prevention of various inflammatory complications and infectious diseases in both diabetics and non-diabetics.

The Role of AMPK Signaling in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease characterized by inflammation and ulcer formation of the intestinal mucosa. Due to its high recurrence rate, prolonged course, limited curative options, and significant impact on patients' quality of life, along with a notable potential for malignant transformation, UC is designated as a refractory global health challenge by the World Health Organization (WHO). The elucidation of the pathogenesis and therapeutic strategies for UC requires further in-depth investigation. AMP-activated protein kinase (AMPK) serves as a central regulator of cellular energy metabolic homeostasis. Emerging evidence indicates that interventions involving traditional Chinese medicine (TCM) components, as well as other pharmacological measures, exert beneficial effects on the intestinal mucosal inflammation and epithelial barrier dysfunction in UC by modulating AMPK signaling, thereby influencing biological processes such as cellular autophagy, apoptosis, inflammatory responses, macrophage polarization, and NLRP3 inflammasome-mediated pyroptosis. The role of AMPK in UC is of significant importance. This manuscript provides a comprehensive overview of the mechanisms through which AMPK is involved in UC, as well as a compilation of pharmacological agents capable of activating the AMPK signaling pathway within the context of UC. The primary objective is to facilitate a deeper comprehension of the pivotal role of AMPK in UC among researchers and clinical practitioners, thereby advancing the identification of novel therapeutic targets for interventions in UC.

Triggerable Prodrug Nanocoating Enables On-Demand Activation of Microbial and Small-Molecular Therapeutics for Combination Treatment

The synergy of living microbial and small-molecular therapeutics has been widely explored for treating a variety of diseases, while current combination strategies often suffer from low bioavailability, heterogeneous spatiotemporal distribution, and premature drug release. Here, the use of a triggerable prodrug nanocoating is reported to enable the on-demand activation of microbial and small-molecular therapeutics for combination treatment. As a proof-of-concept study, a reactive oxygen species-responsive aromatic thioacetal linker is employed to prepare cationic chitosan-drug conjugates, which can form a nanocoating on the surface of living bacteria via electrostatic interaction. Following administration, the wrapped bacteria can be prevented from in vivo insults by the shielding effect of the nanocoating and be co-delivered with the conjugated drug in a spatiotemporally synchronous manner. Upon reaching the lesion site, the upgraded reactive oxygen species trigger in situ cleavage of the thioacetal linker, resulting in the release of the conjugated drug and a linker-derived therapeutic cinnamaldehyde. Meanwhile, a charge reversal achieved by the generation of negatively charged thiolated chitosan induces the dissociation of the nanocoating, leading to synchronous release of the living bacteria. The adequate activation of the combined therapeutics at the lesion site exhibits superior synergistic treatment efficacy, as demonstrated by an in vivo assessment using a mouse model of colitis. This work presents an appealing approach to combine living microbial and small-molecular therapeutics for advanced therapy of diseases.

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.

Will metformin use lead to a decreased risk of thyroid cancer? A systematic review and meta-analyses

BACKGROUND

It has been reported that metformin use may reduce the risk of thyroid cancer, but existing studies have generated inconsistent results. The purpose of this study was to investigate such association between metformin use and the risk of thyroid cancer.

METHODS

Studies of metformin use for the risk of thyroid cancer were searched in Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biomedical Database, Wanfang Data, and Chinese Scientific Journals Database (VIP) from the establishment date to December 2022. Newcastle-Ottawa scale is adopted for assessing the methodological quality of included studies, and the inter-study heterogeneity was assessed by using the I-squared statistic. Combined odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) were calculated through either fixed-effects or random-effects model according to the heterogeneity. Besides, subgroup analyses, sensitivity analyses and test for publication bias were conducted.

RESULTS

Five studies involving 1,713,528 participants were enrolled in the qualitative and quantitative synthesis. The result of the meta-analyses showed that metformin use was associated with a statistically significant lower risk of thyroid cancer (pooled OR = 0.68, 95% CI = 0.50-0.91, P = 0.011). Moreover, in the subgroup analysis, we found that the use of metformin may also aid in the prevention of thyroid cancer in Eastern population (pooled OR = 0.55, 95% CI = 0.35-0.88, P = 0.012) rather than Western population (pooled OR = 0.89, 95% CI = 0.52-1.54, P = 0.685). Sensitivity analysis suggested the results of this meta-analyses were relatively stable. No publication bias was detected.

CONCLUSION

Metformin use is beneficial for reducing the risk of thyroid cancer. For further investigation, more well-designed studies are still needed to elucidate the association between metformin use and the risk of thyroid cancer.

Nanoprobiotics for Remolding the Pro-inflammatory Microenvironment and Microbiome in the Treatment of Colitis

Despite the great progress of current bacterially based biotherapeutics, their unsatisfying efficacy and underlying safety problems have limited their clinical application. Herein, inspired by probiotic Escherichia coli strain Nissle 1917, probiotic-derived outer membrane vesicles (OMVs) are found to serve as an effective therapeutic platform for the treatment of inflammatory bowel disease (IBD). To further enhance the therapeutic effect, the probiotic-derived OMV-encapsulating manganese dioxide nanozymes are constructed, named nanoprobiotics, which can adhere to inflamed colonic epithelium and eliminate intestinal excess reactive oxygen species in the murine IBD model. Moreover, combined with the anti-inflammatory medicine metformin, nanoprobiotics could further remold the pro-inflammatory microenvironment, improve the overall richness and diversity of the gut microbiota, and exhibit better therapeutic efficacy than commercial IBD chemotherapeutics. Importantly, insignificant overt systemic toxicity in this treatment was observed. By integrating cytokine storm calm with biotherapy, we develop a safe and effective bionanoplatform for the effective treatment of inflammation-mediated intestinal diseases.

Metformin may be a viable adjunctive therapeutic option to potentially enhance immune reconstitution in HIV-positive immunological non-responders

ABSTRACT

Incomplete immune reconstitution remains a global challenge for human immunodeficiency virus (HIV) treatment in the present era of potent antiretroviral therapy (ART), especially for those individuals referred to as immunological non-responders (INRs), who exhibit dramatically low CD4 + T-cell counts despite the use of effective antiretroviral therapy, with long-term inhibition of viral replication. In this review, we provide a critical overview of the concept of ART-treated HIV-positive immunological non-response, and also explain the known mechanisms which could potentially account for the emergence of immunological non-response in some HIV-infected individuals treated with appropriate and effective ART. We found that immune cell exhaustion, combined with chronic inflammation and the HIV-associated dysbiosis syndrome, may represent strategic aspects of the immune response that may be fundamental to incomplete immune recovery. Interestingly, we noted from the literature that metformin exhibits properties and characteristics that may potentially be useful to specifically target immune cell exhaustion, chronic inflammation, and HIV-associated gut dysbiosis syndrome, mechanisms which are now recognized for their critically important complicity in HIV disease-related incomplete immune recovery. In light of evidence discussed in this review, it can be seen that metformin may be of particularly favorable use if utilized as adjunctive treatment in INRs to potentially enhance immune reconstitution. The approach described herein may represent a promising area of therapeutic intervention, aiding in significantly reducing the risk of HIV disease progression and mortality in a particularly vulnerable subgroup of HIV-positive individuals.

Metformin beyond an anti-diabetic agent: A comprehensive and mechanistic review on its effects against natural and chemical toxins

In addition to the anti-diabetic effect of metformin, a growing number of studies have shown that metformin has some exciting properties, such as anti-oxidative capabilities, anticancer, genomic stability, anti-inflammation, and anti-fibrosis, which have potent, that can treat other disorders other than diabetes mellitus. We aimed to describe and review the protective and antidotal efficacy of metformin against biologicals, chemicals, natural, medications, pesticides, and radiation-induced toxicities. A comprehensive search has been performed from Scopus, Web of Science, PubMed, and Google Scholar databases from inception to March 8, 2023. All in vitro, in vivo, and clinical studies were considered. Many studies suggest that metformin affects diseases other than diabetes. It is a radioprotective and chemoprotective drug that also affects viral and bacterial diseases. It can be used against inflammation-related and apoptosis-related abnormalities and against toxins to lower their effects. Besides lowering blood sugar, metformin can attenuate the effects of toxins on body weight, inflammation, apoptosis, necrosis, caspase-3 activation, cell viability and survival rate, reactive oxygen species (ROS), NF-κB, TNF-α, many interleukins, lipid profile, and many enzymes activity such as catalase and superoxide dismutase. It also can reduce the histopathological damages induced by many toxins on the kidneys, liver, and colon. However, clinical trials and human studies are needed before using metformin as a therapeutic agent against other diseases.

Efficacy of metformin in prevention of paclitaxel-induced peripheral neuropathy in breast cancer patients: a randomized controlled trial

Background: Paclitaxel-induced peripheral neuropathy (PN) is a serious clinical problem with no approved drug for prevention. This study aimed to examine the neuroprotective effect of metformin against paclitaxel-induced PN in breast cancer patients. Methods: Patients with confirmed breast cancer diagnosis who were planned to receive paclitaxel were randomized to receive either metformin or placebo. Both groups received the standard chemotherapy protocol for breast cancer. Patients started metformin/placebo 1 week before paclitaxel initiation and continued study interventions thereafter for nine consecutive weeks. The primary outcome was the incidence of development of grade two or more paclitaxel-induced sensory PN. The PN was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE). Patients' quality of life (QoL) was assessed by the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACTGOG-Ntx) subscale. Pain severity was measured by the Brief Pain Inventory Short Form (BPI-SF). Serum levels of nerve growth factor (NGF) and neurotensin (NT) were measured at baseline and at the end paclitaxel treatment. Results: A total of 73 patients (36 in the metformin arm and 37 in the control arm) were evaluated. The cumulative incidence of development of grade two or more PN was significantly lower in the metformin arm (14 (38.9%) than the control arm (28 (75.7%); p = 0.001). At the end of paclitaxel treatment, patients' QoL was significantly better in the metformin arm [median (IQR) FACTGOG-Ntx subscale of (24.0 (20.5-26.5)] compared to the control arm (21.0 (18.0-24.0); p = 0.003). The metformin arm showed lower "average" and "worst" pain scores than those detected in the control arm. At the end of the paclitaxel treatment, there was a significant difference in the median serum NGF levels between the two arms, favoring metformin (p < 0.05), while NT serum levels were deemed comparable between the two study arms (p = 0.09). Conclusion: The use of metformin in breast cancer patients offered a marked protection against paclitaxel-induced PN, which translated to better patient QoL. Clinical Trial Registration: https://classic.clinicaltrials.gov/ct2/show/NCT05351021, identifier NCT05351021.

Inhibition of NF-κB Signaling-Mediated Crosstalk Between Macrophages and Preosteoblasts by Metformin Alleviates Trauma-Induced Heterotopic Ossification

Heterotopic ossification (HO) is a pathological condition that occurs in soft tissues following severe trauma. The exact pathogenesis of HO remains unclear. Studies have shown that inflammation predisposes patients to the development of HO and triggers ectopic bone formation. Macrophages are crucial mediators of inflammation and are involved in HO development. The present study investigated the inhibitory effect and underlying mechanism of metformin on macrophage infiltration and traumatic HO in mice. Our results found that abundant levels of macrophages were recruited to the injury site during early HO progression and that early administration of metformin prevented traumatic HO in mice. Furthermore, we found that metformin attenuated macrophage infiltration and the NF-κB signaling pathway in injured tissue. The monocyte-to-macrophage transition in vitro was suppressed by metformin and this event was mediated by AMPK. Finally, we showed that inflammatory mediator's regulation by macrophages targeted preosteoblasts, leading to elevated BMP signaling, and osteogenic differentiation and driving HO formation, and this effect was blocked after the activation of AMPK in macrophages. Collectively, our study suggests that metformin prevents traumatic HO by inhibiting of NF-κB signaling in macrophages and subsequently attenuating BMP signaling and osteogenic differentiation in preosteoblasts. Therefore, metformin may serve as a therapeutic drug for traumatic HO by targeting NF-κB signaling in macrophages.

Pivotal role of AKR1B1 in pathogenesis of colitis associated colorectal carcinogenesis

Identifying the target linking inflammation and oxidative stress to aggravate the disease progression will help to prevent colitis associated carcinogenesis. Since AKR1B1 overexpression is observed in inflammatory diseases and various cancers, we have investigated the role of AKR1B1 in colitis-associated colon carcinogenesis with the aid of epalrestat and its potent analogue NARI-29 (investigational molecule) as pharmacological probes. A TNF-α inducible NF-κB reporter cell line (GloResponse™ NF-κB-RE-luc2P HEK293) and dextran sodium sulfate (DSS) and 1,2 dimethyl hydrazine (DMH))-induced mouse model was used to investigate our hypothesis in vitro and in vivo. Clinically, an increased expression of AKR1B1 was observed in patients with ulcerative colitis. Our in vitro and in vivo findings suggest that the AKR1B1 modulated inflammation and ROS generation for the progression of colitis to colon cancer. AKR1B1 overexpression was observed in DSS + DMH-treated mice colons. Moreover, we could observe histopathological changes like immune cell infiltration, aberrant crypt foci, and tumour formation in DC groups. Mechanistically, we have witnessed modulation of the IKK/IκB/NF-κB and Akt/FOXO-3a/DR axis, increased inflammatory cytokines, increased expression of proliferative markers, Ki-67 and PCNA, and accumulation of β-catenin in the colon epithelium. However, pharmacological inhibition of AKR1B1 using NARI-29 or EPS has reversed the clinical, histopathological, and molecular alterations induced by DSS + DMH, confirming the obvious role of AKR1B1 in the promotion of colitis-associated carcinogenesis. In conclusion, our findings suggest that AKR1B1 targeted therapy could be a promising strategy for preventing CA-CRC and NARI-29 could be developed as a potent AKR1B1 inhibitor.

Metformin Treatment Reduces the Incidence of Rheumatoid Arthritis: A Two-Sample Mendelian Randomized Study

Several studies have shown that rheumatologic patients can benefit from metformin, but it remains unclear whether metformin treatment is causally associated with the risk of rheumatoid arthritis (RA). A two-sample Mendelian randomization (MR) study was conducted to investigate the causal relationship between metformin treatment and the incidence of rheumatoid arthritis. The genome-wide significant (p < 5 × 10^-8) single-nucleotide polymorphisms (SNPs) associated with metformin use were selected as instrumental variables (IVs). Summary statistics on RA were extracted from a large genome-wide association study (GWAS) meta-analysis. The inverse variance-weighted (IVW) method was used as the determinant of the causal effects of metformin treatment on RA. Cochran's Q was used to detect heterogeneity. Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) test and MR-Egger regression were used to detect horizontal pleiotropy. A total of 34 SNPs significantly associated with metformin treatment were obtained. Thirty-two SNPs were selected as IVs after removing two SNPs for being palindromic with intermediate allele frequencies (rs11658063 and rs4930011). The IVW results showed a negative causal association between metformin treatment and RA (OR = 0.0232, 95% CI 1.6046 × 10^-3 - 0.3368; p = 0.006). Meanwhile, no heterogeneity or pleiotropy was detected, indicating that the results were reliable. This study indicated a negative causality between metformin treatment and RA, indicating that the treatment of metformin can prevent the pathogenesis of RA.

Metformin Directly Binds to MMP-9 to Improve Plaque Stability

Vulnerable atherosclerotic plaque rupture is the principal mechanism that accounts for myocardial infarction and stroke. High matrix metalloproteinase-9 (MMP-9) expression and activity have been proven to lead to plaque instability. Metformin, a first-line treatment for type 2 diabetes, is beneficial to plaque vulnerability. However, the mechanism underlying its anti-atherogenic effect remains unclear. Molecular docking and surface plasmon resonance experiments showed that metformin directly interacts with MMP-9, and incubated MMP-9 overexpressing HEK293A cells with metformin (1 μmol·L^-1) significantly attenuates MMP-9's activity using zymography and MMP activity assays. Moreover, metformin treatment drives MMP-9 degradation. Next, we constructed a carotid artery atherosclerotic plaque model and administered consecutive 14-day metformin (200 mg·kg^-1·d^-1) treatment by intragastric gavage. Immunofluorescence staining of the right carotid common artery and serum MMP activity assay results showed that metformin treatment decreased local plaque MMP-9 protein level and circulating MMP-9 activity, respectively. Histochemical staining revealed that after metformin treatment, the collagen content in plaque was significantly preserved, and the plaque vulnerability index decreased. These findings suggested that metformin improved atherosclerotic plaque stability by directly binding to MMP-9 and driving its degradation.

Metabolic Associated Fatty Liver Disease as a Risk Factor for the Development of Central Nervous System Disorders

MAFLD/NAFLD is the most ordinary liver disease categorized by hepatic steatosis with the increase of surplus fat in the liver and metabolic liver dysfunction, which is associated with bigger mortality and a high medical burden. An association between MAFLD/NAFLD and central nervous system disorders including psychological disorders has been demonstrated. Additionally, MAFLD/NAFLD has been correlated with various types of neurodegenerative disorders such as amyotrophic lateral sclerosis or Parkinson’s disease. Contrasted to healthy controls, patients with MAFLD/NAFLD have a greater prevalence risk of extrahepatic complications within multiple organs. Dietary interventions have emerged as effective strategies for MAFLD/NAFLD. The PI3K/AKT/mTOR signaling pathway involved in the regulation of Th17/Treg balance might promote the pathogenesis of several diseases including MAFLD/NAFLD. As extrahepatic complications may happen across various organs including CNS, cooperative care with individual experts is also necessary for managing patients with MAFLD/NAFLD.

Role of metformin in inflammation

BACKGROUND

Metformin has good anti-hyperglycemic effectiveness, but does not induce hypoglycemia，is very safe, and has become the preferred drug for the treatment of type 2 diabetes. Recently, the other effects of metformin, such as being anti-inflammatory and delaying aging, have also attracted increased attention.

METHODS AND RESULTS

The relevant literatures on pubmed and other websites for reading, classification and sorting, and did not involve any animal experiments.

CONCLUSION

Metformin has anti-inflammatory effects through multiple routes, which provides potential therapeutic targets for certain inflammatory diseases, such as neuroinflammation and rheumatoid arthritis. In addition, inflammation is a key component of tumor occurrence and development ; thus, targeted inflammatory intervention is a significant benefit for both cancer prevention and treatment. Therefore, metformin may have further potential for inflammation-related disease prevention and treatmen. However, the inflammatory mechanism is complex; various molecules are connected and influence each other. For example, metformin significantly inhibits p65 nuclear translocation, but pretreatment with compound C, an AMPK inhibitor, abolishes this effect, and silencing of HMGB1 inhibits NF-κB activation . SIRT1 deacetylates FoxO, increasing its transcriptional activity . mTOR in dendritic cells regulates FoxO1 via AKT. The interactions among various molecules should be further explored to clarify their specific mechanisms and provide more direction for the treatment of inflammatory diseases, as well as cancer.

A Novel Perspective on Tissue Engineering Potentials of Periodontal Ligament Stem Cells

It is challenging to completely and predictably regenerate the missing periodontal tissues caused by the trauma or disease. To regenerate the periodontium, there is a need to consider several aspects that co-occur with periodontal development. This study provides an overview of the most up-to-date investigations on the characteristics and immunomodulatory features of Periodontal Ligament Stem Cells (PDLSCs) and the recent interventions performed using these cells, focusing on cell survival, proliferation, and differentiation. Keeping in mind the relationship between age and potency of PDLSCs, this work also demonstrates the necessity of establishing dental-derived stem cell banks for tissue regeneration applications. The data were collected from Pubmed and Google Scholar databases with the keywords of periodontal ligament stem cells, tissue engineering, characteristics, and stem cell therapy. The results showed the presence of wide-ranging research reports supporting the usability of PDLSCs for periodontal reconstruction. However, a better understanding of self-restoration for adequate regulation of adult stem cell growth is needed for various applied purposes.

Repurposing metformin as a potential treatment for inflammatory bowel disease: Evidence from cell to the clinic

Inflammatory bowel disease (IBD) comprises a group of intestinal disorders, including ulcerative colitis and Crohn's disease. Currently, the incidence and prevalence of IBD are increasing globally. Although both biologic agents and small molecule drugs have been available for treatment of IBD patients, approximately one third of treated patients do not respond to these treatments. Therefore, novel therapy or repurposing of drugs have been extensively studied to obtain an effective therapy for IBD patients. Among these drugs, metformin has been reported to exert beneficial effects in many organs via its anti-inflammatory effect. Additionally, evidence from cellular to clinical models of IBD demonstrated significant positive effects of metformin on inflammatory pathways, oxidative stress, gut barrier integrity, and gut microbiota. In this review, the beneficial effects of metformin on IBD are comprehensively summarized and discussed using the results of in vitro, in vivo, and clinical studies. Increased understanding of these protective effects and the underlying mechanisms may pave the way for effective use of metformin in IBD patients.

Cytotoxic effect of metformin on butyrate-resistant PMF-K014 colorectal cancer spheroid cells

Three-dimensional (3D) cell culture models are used in cancer research because they mimic physiological responses in vivo compared with two-dimensional (2D) culture systems. Recently, cross-resistance of butyrate-resistant (BR) cells and chemoresistance in colorectal cancer (CRC) cells have been reported; however, effective treatments for BR cells have not been identified. In this study, we investigated the cytotoxicity of metformin (MET), an anti-diabetic drug, on BR CRC cells in a 3D spheroid culture model. The results demonstrate that MET decreases spheroid size, migration, and spheroid viability, while it increases spheroid death. The molecular mechanism revealed that AMP-activated protein kinase (AMPK) and Akt serine/threonine kinase 1(Akt) were significantly upregulated, whereas the acetyl-CoA-carboxylase (ACC) and mammalian target of rapamycin (mTOR) were downregulated, which led to caspase activation and apoptosis. Our findings show the potential cytotoxicity of MET on CRC-BR cells. The combination of MET and conventional chemotherapeutic drugs should be addressed in further studies to reduce the side effects of standard chemotherapy for CRC.

SIRT1: A promising therapeutic target for chronic pain

Chronic pain remains an unresolved problem. Current treatments have limited efficacy. Thus, novel therapeutic targets are urgently required for the development of more effective analgesics. An increasing number of studies have proved that sirtuin 1 (SIRT1) agonists can relieve chronic pain. In this review, we summarize recent progress in understanding the roles and mechanisms of SIRT1 in mediating chronic pain associated with peripheral nerve injury, chemotherapy‐induced peripheral neuropathy, spinal cord injury, bone cancer, and complete Freund's adjuvant injection. Emerging studies have indicated that SIRT1 activation may exert positive effects on chronic pain relief by regulating inflammation, oxidative stress, and mitochondrial dysfunction. Therefore, SIRT1 agonists may serve as potential therapeutic drugs for chronic pain.

Supplementation with High or Low Iron Reduces Colitis Severity in an AOM/DSS Mouse Model

The relationship between colitis-associated colorectal cancer (CAC) and the dysregulation of iron metabolism has been implicated. However, studies on the influence of dietary iron deficiency on the incidence of CAC are limited. This study investigated the effects of dietary iron deficiency and dietary non-heme iron on CAC development in an azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model. The four-week-old mice were divided into the following groups: iron control (IC; 35 ppm iron/kg) + normal (NOR), IC + AOM/DSS, iron deficient (ID; <5 ppm iron/kg diet) + AOM/DSS, and iron overload (IOL; approximately 2000 ppm iron/kg) + AOM/DSS. The mice were fed the respective diets for 13 weeks, and the AOM/DSS model was established at week five. FTH1 expression increased in the mice’s colons in the IC + AOM/DSS group compared with that observed in the ID and IOL + AOM/DSS groups. The reduced number of colonic tumors in the ID + AOM/DSS and IOL + AOM/DSS groups was accompanied by the downregulated expression of cell proliferation regulators (PCNA, cyclin D1, and c-Myc). Iron overload inhibited the increase in the expression of NF-κB and its downstream inflammatory cytokines (IL-6, TNFα, iNOS, COX2, and IL-1β), likely due to the elevated expression of antioxidant genes (SOD1, TXN, GPX1, GPX4, CAT, HMOX1, and NQO1). ID + AOM/DSS may hinder tumor development in the AOM/DSS model by inhibiting the PI3K/AKT pathway by increasing the expression of Ndrg1. Our study suggests that ID and IOL diets suppress AOM/DSS-induced tumors and that long-term iron deficiency or overload may negate CAC progression.

Tauroursodeoxycholic Acid Inhibits Nuclear Factor Kappa B Signaling in Gastric Epithelial Cells and Ameliorates Gastric Mucosal Damage in Mice

Background/Aims

Previous studies have reported the protective effects of tauroursodeoxycholic acid (TUDCA) on gastric epithelial cells in some animal models, but the precise mechanisms are unclear. This study examined the effects of TUDCA on NF-κB signaling in gastric epithelial cells. Moreover, the protective effects of TUDCA in experimental gastritis models induced by ethanol and NSAID were evaluated and compared with ursodeoxycholic acid (UDCA).

Methods

After a pretreatment with TUDCA or UDCA, human gastric epithelial MKN-45 cells were stimulated with tumor necrosis factor (TNF)-α to activate NF-κB signaling. A real-time PCR (RT-PCR) for human interleukin (IL)-1 mRNA was performed. An electrophoretic mobility shift assay (EMSA) and immunoblot analyses were carried out. In murine models, after a pretreatment with TUDCA or UDCA, ethanol and indomethacin were administered via oral gavage. Macroscopic and microscopic assessments were performed to evaluate the preventive effects of TUDCA and UDCA on murine gastritis.

Results

A pretreatment with TUDCA downregulated the IL-1α mRNA levels in MKN-45 cells stimulated with TNF-α, as assessed by RT-PCR. As determined using EMSA, a pretreatment with TUDCA reduced the TNF-α-induced NF-κB DNA binding activity. A pretreatment with TUDCA inhibited IκBα phosphorylation induced by TNF-α, as assessed by immunoblot analysis. TUDCA attenuated the ethanol-induced and NSAID-induced gastritis in murine models, as determined macroscopically and microscopically.

Conclusions

TUDCA inhibited NF-κB signaling in gastric epithelial cells and ameliorated ethanol- and NSAID-induced gastritis in murine models. These results support the potential of TUDCA for the prevention of gastritis in humans.

Effect of berberine in comparison to metformin on the biophysical and biochemical parameters in diabetic albino Wistar rats

Introduction: Diabetic endothelial dysfunction is accompanied by increased oxidative stress and upregulated proinflammatory and inflammatory mediators in the endothelial vasculature. Aim of this study is to investigate the effect of Berberine, a natural alkaloid, on the oxidative stress, inflammation and its anti-oxidant effect in streptozotocin diabetic rats and to compare the effectiveness of FF with that of Metformin (Met) Material & Methods: This experimental animal study was conducted at animal house. The sample size included 174 albino wistar rats divided into 3 Groups, one control groups (C) Diabetic and untreated and two test groups. T1 Diabetic and treated with metformin 75 mg/kgwt/day) and T2 (T – Diabetics treated with Berberine(Ber) 100 mg/kgwt/day), with 58 rats in each group (29 male & 29 female). All the rats were treated with streptozotocin intra peritoneally and the diabetic state was induced.  T1 group was treated with metformin 75 mg/kg/wt/day. The T2 group of rats were treated with Berberine at a dose of 100 mg/kgwt/day. Blood sample was drawn from retro orbital plexus of animals and the biophysical and biochemical parameters were tested at an interval of 3, 6 and 12-months duration.

Metformin alleviates chronic obstructive pulmonary disease and cigarette smoke extract-induced glucocorticoid resistance by activating the nuclear factor E2-related factor 2/heme oxygenase-1 signaling pathway

Chronic obstructive pulmonary disease (COPD) is an important healthcare problem worldwide. Often, glucocorticoid (GC) resistance develops during COPD treatment. As a classic hypoglycemic drug, metformin (MET) can be used as a treatment strategy for COPD due to its anti-inflammatory and antioxidant effects, but its specific mechanism of action is not known. We aimed to clarify the role of MET on COPD and cigarette smoke extract (CSE)-induced GC resistance. Through establishment of a COPD model in rats, we found that MET could improve lung function, reduce pathological injury, as well as reduce the level of inflammation and oxidative stress in COPD, and upregulate expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), multidrug resistance protein 1 (MRP1), and histone deacetylase 2 (HDAC2). By establishing a model of GC resistance in human bronchial epithelial cells stimulated by CSE, we found that MET reduced secretion of interleukin-8, and could upregulate expression of Nrf2, HO-1, MRP1, and HDAC2. MET could also increase the inhibition of MRP1 efflux by MK571 significantly, and increase expression of HDAC2 mRNA and protein. In conclusion, MET may upregulate MRP1 expression by activating the Nrf2/HO-1 signaling pathway, and then regulate expression of HDAC2 protein to reduce GC resistance.

Intestinal Epithelial AMPK Deficiency Causes Delayed Colonic Epithelial Repair in DSS-Induced Colitis

Dysfunctions in the intestinal barrier, associated with an altered paracellular pathway, are commonly observed in inflammatory bowel disease (IBD). The AMP-activated protein kinase (AMPK), principally known as a cellular energy sensor, has also been shown to play a key role in the stabilization and assembly of tight junctions. Here, we aimed to investigate the contribution of intestinal epithelial AMPK to the initiation, progression and resolution of acute colitis. We also tested the hypothesis that protection mediated by metformin administration on intestinal epithelium damage required AMPK activation. A dextran sodium sulfate (DSS)-induced colitis model was used to assess disease progression in WT and intestinal epithelial cell (IEC)-specific AMPK KO mice. Barrier integrity was analyzed by measuring paracellular permeability following dextran-4kDa gavage and pro-inflammatory cytokines and tight junction protein expression. The deletion of intestinal epithelial AMPK delayed intestinal injury repair after DSS exposure and was associated with a slower re-epithelization of the intestinal mucosa coupled with severe ulceration and inflammation, and altered barrier function. Following intestinal injury, IEC AMPK KO mice displayed a lower goblet cell counts with concomitant decreased Muc2 gene expression, unveiling an impaired restitution of goblet cells and contribution to wound healing process. Metformin administration during the recovery phase attenuated the severity of DSS-induced colitis through improvement in intestinal repair capacity in both WT and IEC AMPK KO mice. Taken together, these findings demonstrate a critical role for IEC-expressed AMPK in regulating mucosal repair and epithelial regenerative capacity following acute colonic injury. Our studies further underscore the therapeutic potential of metformin to support repair of the injured intestinal epithelium, but this effect is conferred independently of intestinal epithelial AMPK.

Metformin ameliorates chronic colitis in a mouse model by regulating interferon-γ-producing lamina propria CD4+ T cells through AMPK activation

Metformin, a commonly prescribed drug for type 2 diabetes mellitus, has been shown to activate AMP-activated protein kinase (AMPK). Notably, AMPK activation has recently been observed to be associated with anti-inflammatory responses. Metformin is also reported to elicit anti-inflammatory responses in CD4+ T cells, resulting in improvement in experimental chronic inflammatory diseases, such as systemic lupus erythematosus. To investigate the effect of metformin on inflammatory bowel disease (IBD), we developed a T cell-transfer model of chronic colitis in which SCID mice were injected with CD4+ CD45RBhigh T cells to induce colitis. We examined the effects of metformin via in vitro and in vivo experiments on lamina propria (LP) CD4+ T cells. We observed that metformin suppresses the frequency of interferon (IFN) -γ-producing LP CD4+ T cells in vitro, which were regulated by AMPK activation, a process possibly induced by the inhibition of oxidative phosphorylation. Furthermore, we examined the effects of metformin on an in vivo IBD model. Metformin-treated mice showed AMPK activation in LP CD4+ T cells and ameliorated colitis. Our study demonstrates that metformin-induced AMPK activation in mucosal CD4+ T cells contributes to the improvement of IBD by suppressing IFN-γ production. Moreover, our results indicate that AMPK may be a target molecule for the regulation of mucosal immunity and inflammation. Thus, AMPK-activating drugs such as metformin may be potential therapeutic agents for the treatment of IBD.

'In vitro' assessments of microencapsulated viable cells as a result of primary bile acid-encapsulated formulation for inflammatory disorders

Background / Aim: Metformin is widely used in type 2 diabetes and exhibits many positive biological effects on pancreatic b-cells and muscle cells, such as supporting insulin release by b-cells and glucose uptake by muscle cells and reducing oxidative stress, particularly due to diabetes-associated hyperglycaemia. Interestingly, for type 1 diabetes, transplantation of healthy b-cells has been proposed as a novel way to replace insulin therapy. Recently, bile acid-formulations containing transplantable b-cells showed best stability. Hence, this study aimed to explore the effects of metformin-bile acid formulations in b-cell encapsulation and on the biological activities of b-cells and muscle-cells. Methods: Two sets of biological effects were examined, using metformin-bile acid formulations, on encapsulated b-cells and on muscle cells exposed to the formulations. Results: Various encapsulated b-cell formulations' cell viability, insulin levels, cellular oxidative stress, cellular inflammatory profile and bioenergetics at the normoand hyperglycaemic states showed differing results based upon the metformin concentration and the inclusion or absence of bile acid. Similar effects were observed with muscle cells. Low ratios of metformin and bile acids showed best biological effects, suggesting a formulation dependent result. The formulations' positive effects were more profound at the hyperglycaemic state suggesting efficient cell protective effects. Conclusion: Overall, metformin had positive impacts on the cells in a concentration-dependent manner, with the addition of chenodeoxycholic acid further improving results.

Metformin for Cardiovascular Protection, Inflammatory Bowel Disease, Osteoporosis, Periodontitis, Polycystic Ovarian Syndrome, Neurodegeneration, Cancer, Inflammation and Senescence: What Is Next?

Diabetes is accompanied by several complications. Higher prevalence of cancers, cardiovascular diseases, chronic kidney disease (CKD), obesity, osteoporosis, and neurodegenerative diseases has been reported among patients with diabetes. Metformin is the oldest oral antidiabetic drug and can improve coexisting complications of diabetes. Clinical trials and observational studies uncovered that metformin can remarkably prevent or alleviate cardiovascular diseases, obesity, polycystic ovarian syndrome (PCOS), osteoporosis, cancer, periodontitis, neuronal damage and neurodegenerative diseases, inflammation, inflammatory bowel disease (IBD), tuberculosis, and COVID-19. In addition, metformin has been proposed as an antiaging agent. Numerous mechanisms were shown to be involved in the protective effects of metformin. Metformin activates the LKB1/AMPK pathway to interact with several intracellular signaling pathways and molecular mechanisms. The drug modifies the biologic function of NF-κB, PI3K/AKT/mTOR, SIRT1/PGC-1α, NLRP3, ERK, P38 MAPK, Wnt/β-catenin, Nrf2, JNK, and other major molecules in the intracellular signaling network. It also regulates the expression of noncoding RNAs. Thereby, metformin can regulate metabolism, growth, proliferation, inflammation, tumorigenesis, and senescence. Additionally, metformin modulates immune response, autophagy, mitophagy, endoplasmic reticulum (ER) stress, and apoptosis and exerts epigenetic effects. Furthermore, metformin protects against oxidative stress and genomic instability, preserves telomere length, and prevents stem cell exhaustion. In this review, the protective effects of metformin on each disease will be discussed using the results of recent meta-analyses, clinical trials, and observational studies. Thereafter, it will be meticulously explained how metformin reprograms intracellular signaling pathways and alters molecular and cellular interactions to modify the clinical presentations of several diseases.

Metformin Exerts Anti-inflammatory and Mucus Barrier Protective Effects by Enriching Akkermansia muciniphila in Mice With Ulcerative Colitis

The present study aimed to determine if metformin exerts anti-inflammatory and mucus-protective effects via the gut microbiota. Metformin has extensive benefits including anti-inflammatory effects. Previous studies showed that metformin changed the gut microbiota composition and increases the number of goblet cells. Intestinal dysbiosis and goblet cell depletion are important features of ulcerative colitis (UC). The underlying mechanism and whether metformin can improve the mucus barrier in UC remain unclear. Metformin (400 mg/kg/day) was administered to mice with dextran sulfate sodium (DSS)-induced UC for 2 wk to investigate the effects of metformin on the intestinal mucus barrier. The gut microbiota was depleted, using antibiotics, to explore its role in the mucus-protecting effects of metformin. Akkermansia muciniphila (A. muciniphila), which was enriched in metformin-treated mice, was administered to mice to investigate the effects of the bacteria on UC and the mucus barrier. Metformin attenuated DSS-induced UC in mice, as evidenced by the alleviation of diarrhea, hematochezia, and the decrease in body weight. The expression of mucin2, a prominent mucus barrier protein, was increased in the metformin-treated group compared to the DSS-treated group. Furthermore, fecal 16S rRNA analysis showed that metformin treatment changed the gut microbiota composition by increasing the relative abundance of Lactobacillus and Akkermansia species while decreasing Erysipelatoclostridium at the genus level. Antibiotic treatment partly abolished the anti-inflammatory and mucus-protecting effects of metformin. Administration of A. muciniphila alleviated the colonic inflammation and mucus barrier disruption. Metformin alleviated DSS-induced UC in mice and protected against cell damage via affecting the gut microbiota, thereby providing a new mechanism for the therapeutic effect of metformin in patients with UC. This study also provides evidence that A. muciniphila as a probiotic has potential benefits for UC.

Evaluation of the effects of metformin as adenosine monophosphate-activated protein kinase activator on spatial learning and memory in a rat model of multiple sclerosis disease

In patients with multiple sclerosis (MS) disease, cognitive deficits have been detected because of destruction of hippocampus. Cognitive impairment is one of the common signs in MS. Recent studies showed that metformin (Met) has wide-ranging effects in the treatment of diseases. Here, we have tried to study the preservative effects of Met as adenosine monophosphate-activated protein kinase (AMPK) activator on the hippocampus dentate gyrus (DG) neuronal firing pattern, motor coordination, and learning & memory loss following MS induction. The MS induction was done by local ethidium bromide (EB) injection into the rat hippocampus. Then, rats were treated with Met (200 mg/kg) for two weeks. Spatial memory and learning status were assessed using Morris water maze. A neuronal single-unit recording was measured from hippocampus DG. After decapitation, the bilateral hippocampi separated to measure malondialdehyde (MDA). Treatment with Met ameliorated latency times and path lengths (P < 0.05, P < 0.01, P < 0.001 in 1th, 2th, 3th and 4th days) in the Met + MS group respectively. The percent of total time spent in goal quarter and the average number of spikes/bin were decreased significantly in MS rats compared with the sham group (p < 0.001) but significantly increased in the metformin-treated MS group (Met + MS), (p < 0.01, p < 0.001). Met treatment in rats with MS significantly reduced the concentration of MDA, which is an indicator of lipid peroxidation compared to untreated groups. These observations show that increase of neuronal activity, sensory-motor coordination, and improvement of spatial memory in MS rats treated with Met appears via an increment of AMPK.

Pharmacological and Biological Study of Microencapsulated Probucol-Secondary Bile Acid in a Diseased Mouse Model

Probucol (PB) is a highly lipophilic drug with potential protective effects on pancreatic β-cells from inflammation and oxidation. PB has poor bioavailability and solubility, and despite many attempts, significant improvement in antidiabetic effects or absorption has yet to be discovered. Recently, the role of bile acids has been established in significant drug formulation stabilisation effects and as cell-penetrating agents. Promising results in pharmaceutical formulation studies on drug stability and release patterns when lithocholic acid (LCA) is conjugated with PB and sodium alginate (SA) have been demonstrated. Thus, this study aimed to develop and characterise PB microcapsules incorporating LCA and examine the biological effects of the microcapsules in vitro and in vivo. PB/LCA microcapsules were prepared using an encapsulation method, ionic gelation vibrational jet flow technology. LCA incorporation in PB microcapsules showed positive effects on β-cells with improved insulin release, antioxidant activity, and PB intracellular uptake. Diabetic mice gavaged LCA-PB microcapsules showed a significant reduction in diabetes signs and symptoms, better survival rate, reduced blood glucose levels, and pro-inflammatory cytokines, with an increase PB level in blood and tissues suggesting a potential therapy for treating diabetes mellitus.

Metformin reduces oxandrolone- induced depression-like behavior in rats via modulating the expression of IL-1β, IL-6, IL-10 and TNF-α

Oxandrolone (OXA) is an androgen and anabolic steroid (AAS) that is used to reverse weight loss associated with some medical conditions. One of the side effects of OXA is its potential to induce depressive symptoms. Growing evidence suggested that neuroinflammation and cytokines play crucial roles in sickness behavioral and associated mood disturbances. Previous studies showed that metformin attenuated neuroinflammation. This study investigated the potential protective role of metformin against OXA-induced depression-like behavior and neuroinflammation. Twenty- four Wistar male rats were randomly grouped into four groups: the control group (Control) received only vehicle; the oxandrolone group (OXA) received oxandrolone (0.28 mg/kg, i.p); the metformin group (MET) received metformin (100 mg/kg, i.p); and the oxandrolone / metformin group (OXA + MET) received both oxandrolone (0.28 mg/kg, i.p) and metformin (100 mg/kg, i.p). These treatments were administered for fourteen consecutive days. Behavioral tests to measure depression-like behavior were conducted before and after treatments. qRT-PCR was used to measure the relative expression of proinflammatory and anti-inflammatory cytokines in the hippocampus and hypothalamus. The results showed that oxandrolone induced depression-like behavior and dysregulated pro-/anti-inflammatory cytokines, while metformin attenuated these effects. These findings suggest that metformin is a potential treatment to reverse the depressive effects induced by oxandrolone that involve neuroinflammatory effects.

Artificial intelligence guided discovery of a barrier-protective therapy in inflammatory bowel disease

Modeling human diseases as networks simplify complex multi-cellular processes, helps understand patterns in noisy data that humans cannot find, and thereby improves precision in prediction. Using Inflammatory Bowel Disease (IBD) as an example, here we outline an unbiased AI-assisted approach for target identification and validation. A network was built in which clusters of genes are connected by directed edges that highlight asymmetric Boolean relationships. Using machine-learning, a path of continuum states was pinpointed, which most effectively predicted disease outcome. This path was enriched in gene-clusters that maintain the integrity of the gut epithelial barrier. We exploit this insight to prioritize one target, choose appropriate pre-clinical murine models for target validation and design patient-derived organoid models. Potential for treatment efficacy is confirmed in patient-derived organoids using multivariate analyses. This AI-assisted approach identifies a first-in-class gut barrier-protective agent in IBD and predicted Phase-III success of candidate agents.

Traditional drug discovery process use differential, Bayesian and other network based approaches. We developed a Boolean approach for building disease maps and prioritizing pre-clinical models to discover a first-in-class therapy to restore and protect the leaky gut barrier in inflammatory bowel disease.

Metformin Modulates T Cell Function and Alleviates Liver Injury Through Bioenergetic Regulation in Viral Hepatitis

Metformin is not only the first-line medication for the treatment of type 2 diabetes, but it is also effective as an anti-inflammatory, anti-oxidative and anti-tumor agent. However, the effect of metformin during viral hepatitis remains elusive. Using an adenovirus (Ad)-induced viral hepatitis mouse model, we found that metformin treatment significantly attenuated liver injury, with reduced serum aspartate transaminase (AST) and alanine transaminase (ALT) levels and liver histological changes, presumably via decreased effector T cell responses. We then demonstrated that metformin reduced mTORC1 activity in T cells from infected mice, as evidenced by decreased phosphorylation of ribosome protein S6 (p-S6). The inhibitory effects on the mTORC1 signaling by metformin was dependent on the tuberous sclerosis complex 1 (TSC1). Mechanistically, metformin treatment modulated the phosphorylation of dynamin-related protein 1 (Drp-1) and mitochondrial fission 1 protein (FIS1), resulting in increased mass in effector T cells. Moreover, metformin treatment promoted mitochondrial superoxide production, which can inhibit excessive T cell activation in viral hepatitis. Together, our results revealed a protective role and therapeutic potential of metformin against liver injury in acute viral hepatitis via modulating effector T cell activation via regulating the mTORC1 pathway and mitochondrial functions.

Repositioning metformin and propranolol for colorectal and triple negative breast cancers treatment

Drug repositioning refers to new uses for existing drugs outside the scope of the original medical indications. This approach fastens the process of drug development allowing finding effective drugs with reduced side effects and lower costs. Colorectal cancer (CRC) is often diagnosed at advanced stages, when the probability of chemotherapy resistance is higher. Triple negative breast cancer (TNBC) is the most aggressive type of breast cancer, highly metastatic and difficult to treat. For both tumor types, available treatments are generally associated to severe side effects. In our work, we explored the effect of combining metformin and propranolol, two repositioned drugs, in both tumor types. We demonstrate that treatment affects viability, epithelial-mesenchymal transition and migratory potential of CRC cells as we described before for TNBC. We show that combined treatment affects different steps leading to metastasis in TNBC. Moreover, combined treatment is also effective preventing the development of 5-FU resistant CRC. Our data suggest that combination of metformin and propranolol could be useful as a putative adjuvant treatment for both TNBC and CRC and an alternative for chemo-resistant CRC, providing a low-cost alternative therapy without associated toxicity.

Metformin: A Novel Weapon Against Inflammation

It has become widely accepted that inflammation is a driving force behind a variety of chronic diseases, such as cardiovascular disease, diabetes, kidney disease, cancer, neurodegenerative disorders, etc. However, the existing nonsteroidal anti-inflammatory drugs show a limited utility in clinical patients. Therefore, the novel agents with different inflammation-inhibitory mechanisms are worth pursuing. Metformin, a synthetic derivative of guanidine, has a history of more than 50 years of clinical experience in treating patients with type 2 diabetes. Intense research efforts have been dedicated to proving metformin’s inflammation-inhibitory effects in cells, animal models, patient records, and randomized clinical trials. The emerging evidence also indicates its therapeutic potential in clinical domains other than type 2 diabetes. Herein, this article appraises current pre-clinical and clinical findings, emphasizing metformin’s anti-inflammatory properties under individual pathophysiological scenarios. In summary, the anti-inflammatory effects of metformin are evident in pre-clinical models. By comparison, there are still clinical perplexities to be addressed in repurposing metformin to inflammation-driven chronic diseases. Future randomized controlled trials, incorporating better stratification/targeting, would establish metformin’s utility in this clinical setting.

Metformin alleviates inflammation in oxazolone induced ulcerative colitis in rats: plausible role of sphingosine kinase 1/sphingosine 1 phosphate signaling pathway

OBJECTIVES

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is associated with high sphingosine kinase 1(SPHK1) expression in the colon, however its role in pathogenesis of UC is not clearly understood so, the aim of the present study was to clarify the role of SPHK1 and investigate whether the anti-inflammatory effects of metformin in UC is mediated by Sphingosine kinase 1/sphingosine 1 phosphate (S1P) signaling pathway.

MATERIAL AND METHODS

Colitis was induced in adult male wistar rats by intra rectal administration of oxazolone in the fifth and seventh days from initial presensitization. Oxazolone treated rats were divided into untreated oxazolone group, metformin and mesalazine treated groups both in a dose of 100 mg/kg/day orally for 21 days. Along with these groups normal control and saline groups were used .Colitis was assessed by colon length, disease activity index (DAI) and histological examination of colontissue. Plasma samples were used to measure S1P.SPHK1 activity, signal transducer and activator of transcription -3(STAT-3), interleukin-6 (IL-6), nitric oxide (NO), myeloperoxidase activity (MPO), reduced glutathione (GSH) and tissue expression of intracellular cell adhesion molecule -1(ICAM-1) and caspase-3 genes were measured in tissue.

RESULTS

Metformin successfully attenuated oxazolone colitis by increasing colon length, decreasing DAI and improved colon histologic picture. Metformin also induced a significant decrease in Plasma SIP, SPHK1 activity, inflammatory, oxidative stress markers, ICAM-1 and Caspase-3 genes expression compared to oxazolone group.

CONCLUSION

It is revealed that metformin alleviated inflammation and underlying mechanism may result from inhibition of SPHK1/S1P signaling pathway.

Increased metformin dosage suppresses pro-inflammatory cytokine levels in systemic circulation and might contribute to its beneficial effects

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder, characterized by persistent elevation of blood glucose either due to insulin resistance or insulin insufficiency. Metformin is the recommended first choice of drug for the management of T2DM and is known to improve insulin sensitivity and prevents hyperglycemia by reducing chronic inflammation. T-helper type 1 (Th1) and type 17 (Th17) cells, are important pro-inflammatory CD4⁺ T cell subsets secreting TNF-α, and INF-γ (Th1), and interleukin 17 (Th17). These cytokines have been shown to play a crucial role in inflammation, insulin resistance, and the development of T2DM. Here, we explore the effect of different metformin dosages on pro-inflammatory cytokine (TNF-α, INF-γ, GM-CSF and IL-17) levels in systemic circulation among T2DM patients in Ghana, since inflammatory responses and cytokines play significant roles in the pathogenesis and progression of T2DM patients on metformin. Two hundred and nine (209) consenting T2DM patients receiving treatment at the Diabetic unit of the Komfo Anokye Teaching Hospital (KATH) in the Ashanti region of Ghana were recruited in a hospital-based cross-sectional study design. Blood samples were collected and serum obtained from each participant were analyzed for the concentrations of TNF-α, INF-γ, GM-CSF and IL-17 cytokine levels by solid-phase sandwich ELISA. We observed that participants on 3000 mg/day dose of metformin had significantly lower levels of TNF-α (p < .001) and IFN-γ (p = .014) compared to those on other dosages (1000 mg and 2000 mg/day). However, GM-CSF and IL-17 levels were not affected by increased metformin dosages. After adjusting for age, gender, dose and duration of metformin use, we observed that participants who took higher doses of metformin had significantly reduced levels of TNF-α (β = -0.0297, 95% CI = (-0.005 to -0.002) p < .001. Metformin dosage independently predicted reduced TNF-α levels with 14.4% variations in the metformin dosage levels. Increased metformin dosage suppresses TNF-α levels in systemic circulation and hence might contribute to its beneficial effects.

The Fatty Acid Lipid Metabolism Nexus in COVID-19

Enteric symptomology seen in early-stage severe acute respiratory syndrome (SARS)-2003 and COVID-19 is evidence of virus replication occurring in the intestine, liver and pancreas. Aberrant lipid metabolism in morbidly obese individuals adversely affects the COVID-19 immune response and increases disease severity. Such observations are in line with the importance of lipid metabolism in COVID-19, and point to the gut as a site for intervention as well as a therapeutic target in treating the disease. Formation of complex lipid membranes and palmitoylation of coronavirus proteins are essential during viral replication and assembly. Inhibition of fatty acid synthase (FASN) and restoration of lipid catabolism by activation of AMP-activated protein kinase (AMPK) impede replication of coronaviruses closely related to SARS-coronavirus-2 (CoV-2). In vitro findings and clinical data reveal that the FASN inhibitor, orlistat, and the AMPK activator, metformin, may inhibit coronavirus replication and reduce systemic inflammation to restore immune homeostasis. Such observations, along with the known mechanisms of action for these types of drugs, suggest that targeting fatty acid lipid metabolism could directly inhibit virus replication while positively impacting the patient's response to COVID-19.

Posttranslational modifications as therapeutic targets for intestinal disorders

A variety of biological processes are regulated by posttranslational modifications. Posttranslational modifications including phosphorylation, ubiquitination, glycosylation, and proteolytic cleavage, control diverse physiological functions in the gastrointestinal tract. Therefore, a better understanding of their implications in intestinal diseases, including inflammatory bowel disease, irritable bowel syndrome, celiac disease, and colorectal cancer would provide a basis for the identification of novel biomarkers as well as attractive therapeutic targets. Posttranslational modifications can be common denominators, as well as distinct biomarkers, characterizing pathological differences of various intestinal diseases. This review provides experimental evidence that identifies changes in posttranslational modifications from patient samples, primary cells, or cell lines in intestinal disorders, and a summary of carefully selected information on the use of pharmacological modulators of protein modifications as therapeutic options.

Mogrol, an aglycone of mogrosides, attenuates ulcerative colitis by promoting AMPK activation

BACKGROUND

Ulcerative colitis (UC) is a non-specific chronic inflammatory disease. The incidence of UC in China has been increasing in recent years. Mogrol is an aglycone of mogrosides. Studies have shown that mogrosides have anti-oxygenation, anti-inflammatory, and laxative effects as well as other biological activities.

PURPOSE

To investigate the beneficial effects of mogrol on UC and identify its underlying mechanisms.

STUDY DESIGN

We used the dextran sodium sulphate (DSS)-induced UC model in mice, TNF-α-damaged NCM460 colonic epithelial cells, macrophage cells THP-M stimulated with lipopolysaccharide (LPS) / adenosine triphosphate (ATP) and compound C (an AMPK inhibitor) to confirm the key role of AMPK (AMP-activated protein kinase) activation.

METHODS

Histological evaluation, immunohistochemical staining, Western blot analysis, immunofluorescence assay and quantitative real time-PCR were used in the study.

RESULTS

Oral administration of mogrol (5 mg/kg/daily) in vivo significantly attenuated pathological colonic damage, inhibited inflammatory infiltration and improved the abnormal expression of NLRP3 inflammasome in colonic mucosa via the AMPK and NF-κB signaling pathways. In vitro, mogrol protected against intestinal epithelial barrier dysfunction by activating AMPK in TNF-α-treated NCM460 cells and inhibited the production of inflammatory mediator in LPS-stimulated THP-M cells. Furthermore, mogrol's effects were reversed by compound C intervention in DSS-induced UC model.

CONCLUSION

Mogrol exerts protective effects in experimental UC and inhibits production of inflammatory mediators through activation of AMPK-mediated signaling pathways.

Low-dose metformin treatment in the subacute phase improves the locomotor function of a mouse model of spinal cord injury

Metformin, a first-line drug for type-2 diabetes, has been shown to improve locomotor recovery after spinal cord injury. However, there are studies reporting no beneficial effect. Recently, we found that high dose of metformin (200 mg/kg, intraperitoneal) and acute phase administration (immediately after injury) led to increased mortality and limited locomotor function recovery. Consequently, we used a lower dose (100 mg/kg, i.p.) metformin in mice, and compared the effect of immediate administration after spinal cord injury (acute phase) with that of administration at 3 days post-injury (subacute phase). Our data showed that metformin treatment starting at the subacute phase significantly improved mouse locomotor function evaluated by Basso Mouse Scale (BMS) scoring. Immunohistochemical studies also revealed significant inhibitions of microglia/macrophage activation and astrogliosis at the lesion site. Furthermore, metformin treatment at the subacute phase reduced neutrophil infiltration. These changes were in parallel with the increased survival rate of spinal neurons in animals treated with metformin. These findings suggest that low-dose metformin treatment for subacute spinal cord injury can effectively improve the functional recovery possibly through anti-inflammation and neuroprotection. This study was approved by the Institute Animal Care and Use Committee at the University of Texas Medical Branch (approval No. 1008041C) in 2010.

Cytotoxicity of metformin against HT29 colon cancer cells contributes to mitochondrial Sirt3 upregulation

Cancer and diabetes, the two mitochondria-related diseases, have recently been linked to silent mating-type information regulation 2 homolog 3 (SIRT3) activity irregularities. In this study, the effect of metformin, an antidiabetic with anticancer properties, has been evaluated on mitochondrial functionality markers, cell death pathways, and SIRT3 enzyme activity in the colon cancer cell line, HT-29, and human embryonic kidney cells (HEK 293). HT-29 cells were treated with metformin (5, 10, 20, 40, and 80 µM) for 24, 48, and 72 h for measuring the IC₅₀ concentration. Reactive oxygen species (ROS) production, apoptosis, mitochondrial membrane potential, SIRT3 activity, and expression were evaluated against the colon cancer cell line, HT-29. Results indicated a higher ROS production at 6 than 12 h with metformin treatment. Metformin modified the mitochondrial membrane potential, resulting in cell death induction. Results from SIRT3 activity and expression showed that metformin increased its activity and expression in cancer cells. In conclusion, metformin in HT-29 cells disturbed the mitochondrial activity via increased ROS levels and SIRT3 activity, and these rapid modifications may play a key role in its cytotoxic property.

Neuromodulatory effects of green coffee bean extract against brain damage in male albino rats with experimentally induced diabetes

Diabetes mellitus is an increasing metabolic disease worldwide associated with central nervous system disorders. Coffee is a widely consumed beverage that enriched with antioxidants with numerous medicinal applications. Accordingly, the present study aimed to investigate the therapeutic potential of orally administered green coffee bean water extract (GCBWE) against cortical damage induced by high fat diet (HFD) followed by a single injection of streptozotocin (STZ) in rats. Metformin (Met) was used as standard antidiabetic drug. Animals were allocated into six groups: control, GCBWE (100 mg/kg), HFD/STZ (40 mg/kg), HFD/STZ + GCBWE (50 mg/kg), HFD/STZ + GCBWE (100 mg/kg) and HFD/STZ + Met (200 mg/kg) which were treated daily for 28 days. Compared to control rats, HFD/STZ-treated rats showed decreased levels of cortical dopamine, norepinephrine and serotonin with marked increases in their metabolites. Further, HFD/STZ treatment resulted in notable elevations in malondialdehyde, protein carbonyl and total nitrite levels paralleled with declines in antioxidant markers (SOD, CAT, GPx, GR and GSH) and down-regulations of Sod2, Cat, GPx1 and Gsr gene expression. Neuroinflammation was evident in diabetic animals by marked elevations in TNF-α, IL-1β and up-regulation of inducible nitric oxide synthase. Significant rises incaspase-3 and Bax with decline in Bcl-2 level were noticed in diabetic rats together with similar results in their gene expressions. Cortical histopathological examination supported the biochemical and molecular findings. GCBWE administration achieved noteworthy neuroprotection in diabetic animals in most assessed parameters. The overall results suggested that antioxidant, anti-inflammatory; anti-apoptotic activities of GCBWE restored the cortical neurochemistry in diabetic rats.

Icariin enhances AMP-activated protein kinase and prevents high fructose and high salt-induced metabolic syndrome in rats

Metabolic syndrome (MetS) is an increasing health threat and often leads to cardiovascular complications. The aim of this study was to evaluate icariin’s ability to combat MetS induced in rats and outline the involved mechanisms of action. Rats were grouped in four batches. The controls received a regular diet and water. MetS was induced in the remaining three groups using a high-salt high-fructose diet. Groups 1 and 2 were given daily doses of saline, while Groups 3 and 4 received 25 and 50 mg/kg icariin, respectively, for 12 weeks in total. The experimental protocol was carried out for 12 weeks consecutively. Icariin significantly decreased body mass index (BMI), adiposity index and body weight. Further, icariin protected against dyslipidemia, hyperglycemia, and hyperinsulinemia and improved insulin resistance as given by the homeostatic model assessment of insulin resistance (HOMA-IR) values. Icariin guarded against the rise in serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α). In addition, it significantly inhibited the decrease in mRNA expression of glucose transporter type 4 (GLUT4) and liver kinase B1 (LKB1). These effects were accompanied by decreased liver content of nuclear factor kappa B (NFκB) and enhanced serum levels of phosphorylated 5ʹ-adenosine monophosphate-activated protein kinase (p-AMPK). Further, icariin significantly increased p-AMPK/AMPK ratio in liver tissues. Conclusively, icariin offers protection in experimentally induced MetS, partially due to AMPK activation.