Metformin and low dose radiation modulates cisplatin-induced oxidative injury in rat via PPAR-γ and MAPK pathways

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.

Metformin counters oxidative stress and mitigates adverse effects of radiation exposure: An overview

Metformin (1,1-dimethylbiguanidine hydrochloride) (MF) is a drug that has long been in use for the treatment of type 2 diabetes mellitus and recently is coming into use in the radiation therapy of cancer and other conditions. Exposure to ionizing radiation disturbs the redox homeostasis of cells and causes damage to proteins, membranes, and mitochondria, destroying a number of biological processes. After irradiation, MF activates cellular antioxidant and repair systems by signaling to eliminate the harmful consequences of disruption of redox homeostasis. The use of MF in the treatment of the negative effects of irradiation has great potential in medical patients after radiotherapy and in victims of nuclear accidents or radiologic terrorism.

Combination of metformin and hesperidin mitigates cyclophosphamide-induced hepatotoxicity. Emerging role of PPAR-γ/Nrf-2/NF-κB signaling pathway

Cyclophosphamide (CP) is widely used as an immunosuppressive and chemotherapeutic drug. However, its therapeutic application is restricted by its adverse effects, particularly hepatotoxicity. Both metformin (MET) and hesperidin (HES) have promising antioxidant, anti-inflammatory, and anti-apoptotic effects. Therefore, the principal aim of the current study is to investigate the hepatoprotective effects of MET, HES, and their combinations on the CP-induced hepatotoxicity model. Hepatotoxicity was evoked by a single (I.P) injection of CP (200 mg/kg) on day 7. For this study, 64 albino rats were randomly categorized into eight equal groups; naïve, control vehicle, untreated CP (200 mg/kg, IP), and CP 200 groups treated with MET 200, HES 50, HES 100 or a combination of MET 200 with HES 50 and HES 100 respectively orally daily for 12 days. At the end of the study, the liver function biomarkers, oxidative stress, inflammatory parameters, histopathological and immunohistochemical analysis of PPAR-γ, Nrf-2, NF-κB, Bcl-2, and caspase3 were assessed. CP significantly increased serum ALT, AST, total bilirubin, hepatic MDA, NO content, NF-κB, and TNF-α. Otherwise, albumin, hepatic GSH content, Nrf-2, and PPAR-γ expression decreased considerably compared to the control vehicle group. The combinations of MET200 with HES50 or HES100 induced pronounced hepatoprotective, anti-oxidative, anti-inflammatory, and anti-apoptotic effects on CP-treated rats. The possible explanation of such hepatoprotective effects may be mediated via upregulation of Nrf-2, PPAR-γ, Bcl-2 expression, hepatic GSH content, and marked suppression of TNF-α and NF-κB expression. In conclusion, the current study showed that combining MET and HES revealed a remarkable hepatoprotective effect against CP-induced hepatotoxicity.

Is Nuclear Factor Erythroid 2-Related Factor 2 a Target for the Intervention of Cytokine Storms?

The term "cytokine storm" describes an acute pathophysiologic state of the immune system characterized by a burst of cytokine release, systemic inflammatory response, and multiple organ failure, which are crucial determinants of many disease outcomes. In light of the complexity of cytokine storms, specific strategies are needed to prevent and alleviate their occurrence and deterioration. Nuclear factor erythroid 2-related factor 2 (NRF2) is a CNC-basic region-leucine zipper protein that serves as a master transcription factor in maintaining cellular redox homeostasis by orchestrating the expression of many antioxidant and phase II detoxification enzymes. Given that inflammatory response is intertwined with oxidative stress, it is reasonable to assume that NRF2 activation limits inflammation and thus cytokine storms. As NRF2 can mitigate inflammation at many levels, it has emerged as a potential target to prevent and treat cytokine storms. In this review, we summarized the cytokine storms caused by different etiologies and the rationale of interventions, focusing mainly on NRF2 as a potential therapeutic target.

Role of low-dose radiation in senescence and aging: A beneficial perspective

Cellular senescence refers to the permanent arrest of cell cycle caused by intrinsic and/or extrinsic stressors including oncogene activation, irradiation, DNA damage, oxidative stress, and certain cytokines (including senescence associated secretory phenotype). Cellular senescence is an important factor in aging. Accumulation of senescent cells has been implicated in the causation of various age-related organ disorders, tissue dysfunction, and chronic diseases. It is widely accepted that the biological effects triggered by low-dose radiation (LDR) are different from those caused by high-dose radiation. Experimental evidence suggests that LDR may promote growth and development, enhance longevity, induce embryo production, and delay the progression of chronic diseases. The underlying mechanisms of these effects include modulation of immune response, stimulation of hematopoietic system, antioxidative effect, reduced DNA damage and improved ability for DNA damage repair. In this review, we discuss the possible mechanisms by which LDR prevents senescence and aging from the perspectives of inhibiting cellular senescence and promoting the removal of senescent cells. We review a wide broad of evidence about the beneficial impact of LDR in senescence and aging models (including cardiovascular diseases, neurological diseases, arthritis and osteoporosis, chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis) to highlight the potential value of LDR in preventing aging and age-related diseases. However, there is no consensus on the effect of LDR on human health, and several important aspects require further investigation.

Protective effects of low-temperature plasma on cisplatin-induced nephrotoxicity

The application of atmospheric pressure low-temperature plasma (LTP) in medical treatment has received extensive attention owing to its redox regulatory and anti-inflammatory properties. Nephrotoxicity due to oxidative stress and inflammation is the main adverse effect of cisplatin. In the present study, rats with cisplatin-induced nephrotoxicity were treated with LTP to investigate its potential protective effect. The results showed that LTP treatment has multiple protective effects on cisplatin-induced nephrotoxicity. It significantly improved clinical indicators such as survival rate, water intake, food intake, body weight, and mobility, as well as physiological indexes such as reduced renal index and levels of serum urea, creatinine, and total bilirubin; pathological indicators such as reduced tubular injury, inflammatory infiltration, tubulointerstitial fibrosis, and apoptosis; cell survival indicators such as decreased protein levels of Caspase-3 and Bax and increased Bcl-2; anti-oxidation status such as reduced malondialdehyde content and increased activities of catalase, superoxide dismutase, and glutathione peroxidase; and reduced inflammatory factors such as TNF-α in kidney tissues. Specially, LTP treatment did not influence the anticancer effect of cisplatin as observed in the solid tumor mouse model established by subcutaneously inoculating H22 cells. Moreover, LTP did not influence the physiological and pathological indicators of normal rats, suggesting its biological safety. In conclusion, LTP can protect against cisplatin-induced nephrotoxicity through its anti-oxidation, anti-inflammation, and anti-apoptosis effects, without influencing the anticancer effect of cisplatin.

Jekyll and Hyde: nuclear receptors ignite and extinguish hepatic oxidative milieu

Nuclear receptors (NRs) are ligand-binding transcription factors that regulate gene networks and physiological responses. Often oxidative stress precedes the onset of liver diseases, and Nrf2 is a key regulator of antioxidant pathways. NRs crosstalk with Nrf2, since NR activation can influence the oxidative milieu by modulating reductive cellular processes. Diet and xenobiotics also regulate NR expression and activity, suggesting a feedback loop. Depending on the tissue context and cues, NRs either increase or decrease toxicity and oxidative damage. Many FDA-approved drugs target NRs, and one could potentially repurpose them to ameliorate reactive oxygen species (ROS). Here, we discuss how several NRs modulate oxidative stress subsequent to diet, organic pollutants, and drug-induced injury to the liver.

Changes in the gut microbiome influence the hypoglycemic effect of metformin through the altered metabolism of branched-chain and nonessential amino acids

AIMS

Although metformin has been reported to affect the gut microbiome, the mechanism has not been fully determined. We explained the potential underlying mechanisms of metformin through a multiomics approach.

METHODS

An open-label and single-arm clinical trial involving 20 healthy Korean was conducted. Serum glucose and insulin concentrations were measured, and stool samples were collected to analyze the microbiome. Untargeted metabolomic profiling of plasma, urine, and stool samples was performed by GC-TOF-MS. Network analysis was applied to infer the mechanism of the hypoglycemic effect of metformin.

RESULTS

The relative abundances of Escherichia, Romboutsia, Intestinibacter, and Clostridium were changed by metformin treatment. Additionally, the relative abundances of metabolites, including carbohydrates, amino acids, and fatty acids, were changed. These changes were correlated with energy metabolism, gluconeogenesis, and branched-chain amino acid metabolism, which are major metabolic pathways related to the hypoglycemic effect.

CONCLUSIONS

We observed that specific changes in metabolites may affect hypoglycemic effects through both pathways related to AMPK activation and microbial changes. Energy metabolism was mainly related to hypoglycemic effects. In particular, branched-chain amino acid metabolism and gluconeogenesis were related to microbial metabolites. Our results will help uncover the potential underlying mechanisms of metformin through AMPK and the microbiome.

The potential hepatoprotective effect of metformin in hepatitis C virus-infected adolescent patients with beta thalassemia major: Randomised clinical trial

BACKGROUND

Iron overload-induced oxidative stress and transfusion-acquired hepatitis C virus (HCV) infection are the main reasons of liver damage in beta thalassemia major (β-TM).

OBJECTIVES

Based on metformin's hepatic benefits in nondiabetic populations, the study aims to investigate the safety and the potential hepatoprotective effect of metformin in HCV-infected β-TM adolescent patients.

METHODS

This was a prospective, randomised, parallel, controlled, open-label study in which 60 HCV-infected β-TM adolescent patients aged 11 to 18 years and receiving no antiviral therapy were selected and randomly assigned to treatment or control group in 1:1 allocation. Both groups were receiving β-TM standard-of-care regimen, whereas metformin (500 mg, twice daily) was added to the treatment group's regimen only. Patients were prospectively followed up for 6 months with assessment of liver biochemical profile, oxidative stress markers, liver fibrosis, clinical symptom improvement and metformin's adverse effects.

RESULTS

Aspartate aminotransferase serum level decreased significantly over time in the treatment group only (P = .013). However, improvement was not clinically significant and did not attain normality. Change in total antioxidant capacity and malondialdehyde serum levels indicated significantly improved oxidative stress status in the treatment group versus significant deterioration in the control group (P < .001). Fibrosis grade improvement was observed in 14 patients in the treatment group versus one improved case in the control group.

CONCLUSION

The use of metformin in HCV-infected β-TM adolescent patients as an adjuvant antioxidant hepatoprotective agent is promising and can improve liver damage.

Concerted outcome of metformin and low dose of radiation in modulation of cisplatin induced uremic encephalopathy via renal and neural preservation

AIM

The therapeutic expediency of cisplatin was limited due to its nephrotoxic side effects, so this study planned to assess the nephrotic and neuroprotective impact of metformin (MET) and low-dose radiation (LDR) in cisplatin-prompted kidney injury and uremic encephalopathy (UE).

METHODS

The effect of the 10-day MET treatment (200 mg/kg, orally) and/or fractionated LDR (0.25 Gy, of the total dose of 0.5 Gy, 1st and 7th day, respectively) on (5 mg/kg, intraperitoneally) cisplatin as a single dose was administered at the 5th day. Serum urea, creatinine and renal kidney injury molecule-1 were measured for the assessment of kidney function. Furthermore, the antioxidant potential in the renal and brain tissues was evaluated through, malondialdehyde and reduced glutathione estimation. Moreover, renal apoptotic markers: AMP-activated protein kinase, lipocalin, B-cell lymphoma 2 associated X protein, B-cell lymphoma 2, P53 and beclin 1 were estimated. UE was evaluated through the determination of serum inflammatory markers: nuclear factor kappa B, tumor-necrosis factor-α and interleukin 1 beta likewise, the cognitive deficits were assessed via forced swimming test, gamma-aminobutyric acid, n-methyl-d-aspartate and neuronal nitric oxide synthases besides AMP-activated protein kinase, light chain 3 and caspase3 levels in rats' cerebella.

KEY FINDINGS

The obtained results revealed a noticeable improvement in the previously mentioned biochemical factors and behavioral tasks that was reinforced by histopathological examination when using the present remedy.

SIGNIFICANCE

metformin and low doses of radiation afforded renoprotection and neuroprotection against cisplatin-induced acute uremic encephalopathy.

Lucrative antioxidant effect of metformin against cyclophosphamide induced nephrotoxicity

Cyclophosphamide is anticancer drug with a well-Known nephrotoxicity. This work was applied to study the lucrative antioxidant influence of metformin as co-therapy on the nephrotoxicity induced by cyclophosphamide in the treatment of different cancer diseases. Four groups of male Sprague Dawley rats were used; Control group (C) received single I.P. injection of 0.2 ml saline, Metformin (MET) group received daily gavage of 200 mg/kg metformin for two weeks, Cyclophosphamide (CP) group received single I.P. injection of 200 mg/kg CP, Protector group (CP.MET) received daily gavage of 200 mg/kg metformin for two weeks and single I.P. injection of 200 mg/kg CP at day 7. By day 14 rats were euthanized. Samples were collected from kidney tissues and blood for kidney function evaluation, histopathological and assessment of oxidative stress markers. The results disclosed that CP yields many functional and structural damage to the kidney, worsened oxidative stress markers and kidney function indicators. The protector group displayed better kidney tissue morphology, acceptable kidney function indicators as well as satisfactory oxidative stress markers.

In assumption, metformin could be combined with CP owing to its lucrative effect counter to CP persuaded nephrotoxicity.

Long-term metformin therapy improves neurobehavioral functions and antioxidative activity after cerebral ischemia/reperfusion injury in rats

Metformin (MET),an antidiabetic drug, has shown antioxidative and neuroprotective effects. In the present investigation, we aimed to study the probable effects of MET on cerebral ischemia/reperfusion in rats. Rats underwent cerebral ischemia/reperfusion and MET was administered orally at doses of 100 and 200 mg/kg for 56 days. Anxiety- and depressive-like behaviors were evaluated by elevated plus-maze or forced swimming tests, respectively. was assessed by. Cognitive functions were assessed by Y-maze continuous alternation task and morris water maze. The activity of SOD and the level of BDNF were measured in brains samples. Our results showed that administration of 200 mg/kg MET reduced the percent of brain edema (84.00 ± 2.13) in comparison with the ischemic animals (91.25 ± 2.25) (p < 0.05). Administration of 200 mg/kg MET in ischemic animals improved anxiety-like behavior by increasing the percentage of the open arms entries (46.51 ± 3.13) and the percentage of the open arms time (32.70 ± 2.49) in comparison with the cerebral ischemia group (26.35 ± 7.02 and 15.32 ± 5.78, respectively) (all p < 0.001). MET treatment (200 mg/kg) increased the cognition index of correct alternations (90.20 ± 4.95) in comparison with the cerebral ischemia group (59.50 ± 8.01) (p < 0.05). MET at the both doses reduced escape latency compared to the cerebral ischemia animals (all p < 0.05). In addition, 200 mg/kg MET increased the time spent in the target quadrant (16.06 ± 0.58) in comparison with the ischemic animals (9.84 ± 0.92) (p < 0.001) and the both doses of the drug increased the number of crossing (5.42 ± 0.36 and 6.5 ± 0.42, respectively) compared to the cerebral ischemia group (3.75 ± 0.31) (p < 0.05 and p < 0.001, respectively). Moreover, 200 mg/kg MET reduced the immobility time (47.50 ± 9.00) in comparison with the cerebral ischemia group (93.43 ± 8.28) (p < 0.001). Furthermore, the both doses of MET increased the BDNF levels (4590 ± 197.6 and 4767 ± 44.10, respectively) in comparison with the ischemic animals (3807 ± 42.56) (p < 0.01 and p < 0.001, respectively). Also, the both doses of the drug increased the SOD activity of brain (52.67 ± 0.33 and 55.00 ± 0.57, respectively) compared to the ischemic animals (49.33 ± 0.33) (p < 0.01 and p < 0.001, respectively). Based on our data, long-term MET therapy may improve behavioral disorders following cerebral ischemia/reperfusion and can be considered as a novel therapeutic approach for the treatment of brain ischemic conditions.

Elevated CD54 Expression Renders CD4+ T Cells Susceptible to Natural Killer Cell-Mediated Killing

BACKGROUND

Natural killer (NK) cells are an important type of effector cell in the innate immune response, and also have a role in regulation of the adaptive immune response. Several studies have indicated that NK cells may influence CD4+ T cells during HIV infection.

METHODS

In total, 51 HIV-infected individuals and 15 healthy controls participated in this study. We performed the flow cytometry assays and real-time PCR for the phenotypic analysis and the functional assays of NK cell-mediated deletion of CD4+ T cells, phosphorylation of nuclear factor-κB (NF-κB/p65) and the intervention of metformin.

RESULTS

Here we detected high CD54 expression on CD4+ T cells in HIV-infected individuals, and demonstrate that upregulated CD54 is associated with disease progression in individuals infected with HIV. We also show that CD54 expression leads to the deletion of CD4+ T cells by NK cells in vitro, and that this is modulated by NF-κB/p65 signaling. Further, we demonstrate that metformin can suppress CD54 expression on CD4+ T cells by inhibiting NF-κB/p65 phosphorylation.

CONCLUSIONS

Our data suggest that further studies to evaluate the potential role of metformin as adjunctive therapy to reconstitute immune function in HIV-infected individuals are warranted.

Metformin regulates adiponectin signalling in epicardial adipose tissue and reduces atrial fibrillation vulnerability

Epicardial adipose tissue (EAT) remodelling is closely related to the pathogenesis of atrial fibrillation (AF). We investigated whether metformin (MET) prevents AF‐dependent EAT remodelling and AF vulnerability in dogs. A canine AF model was developed by 6‐week rapid atrial pacing (RAP), and electrophysiological parameters were measured. Effective refractory periods (ERP) were decreased in the left and right atrial appendages as well as in the left atrium (LA) and right atrium (RA). MET attenuated the RAP‐induced increase in ERP dispersion, cumulative window of vulnerability, AF inducibility and AF duration. RAP increased reactive oxygen species (ROS) production and nuclear factor kappa‐B (NF‐κB) phosphorylation; up‐regulated interleukin‐6 (IL‐6), tumour necrosis factor‐α (TNF‐α) and transforming growth factor‐β1 (TGF‐β1) levels in LA and EAT; decreased peroxisome proliferator‐activated receptor gamma (PPARγ) and adiponectin (APN) expression in EAT and was accompanied by atrial fibrosis and adipose infiltration. MET reversed these alterations. In vitro, lipopolysaccharide (LPS) exposure increased IL‐6, TNF‐α and TGF‐β1 expression and decreased PPARγ/APN expression in 3T3‐L1 adipocytes, which were all reversed after MET administration. Indirect coculture of HL‐1 cells with LPS‐stimulated 3T3‐L1 conditioned medium (CM) significantly increased IL‐6, TNF‐α and TGF‐β1 expression and decreased SERCA2a and p‐PLN expression, while LPS + MET CM and APN treatment alleviated the inflammatory response and sarcoplasmic reticulum Ca²⁺ handling dysfunction. MET attenuated the RAP‐induced increase in AF vulnerability, remodelling of atria and EAT adipokines production profiles. APN may play a key role in the prevention of AF‐dependent EAT remodelling and AF vulnerability by MET.

Therapeutic Effects of Total Saponins From Dioscorea nipponica Makino on Gouty Arthritis Based on the MAPK-PPARγ Signaling Pathway: An In Vitro Study

Gouty arthritis (GA) is an inflammatory disease caused by the deposition of monosodium urate in the synovial membrane and cartilage due to a high concentration of uric acid in the blood. Dioscorea nipponica Makino is widely used in the clinic to treat GA. Total saponins are its main components and showed an anti-inflammatory effect on GA in a previous study. The mitogen-activated protein kinase (MAPK)-peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway plays a key role during the onset of GA; however, little is known about its potential mechanism. Based on in vitro experiments, this study aims to determine the mechanism of total saponins from Dioscorea nipponica Makino (TDN) in treating GA by regulating the MAPK-PPARγ signaling pathway. Fibroblast-like synoviocytes were divided into 3 groups: the model group, which was given 10 µg/L IL-1β to induce proliferation; TDN group (10 µg/L IL-1β + 100 µg/L TDN); and indomethacin group (10 µg/L IL-1β + 100 µg/L indomethacin). Seventy-two hours after treatment, the real-time PCR method was used to detect the mRNA expression levels of extracellular signal regulated kinase 1/2 (ERK1/2), p-38, c-Jun N-terminal kinase (JNK), IKKα, c-Jun, MAPK phosphatase (MKP), vascular cell adhesion molecule 1 (VCAM1), intercellular adhesion molecule 1 (ICAM1), C-X-C motif chemokine ligand 1 (CXCL1), PPARγ, and Adipor2. The Western blot method was used to detect the protein expression of ERK1/2, p-ERK1/2, p-38, p-P38, JNK, p-JNK, IKKα, p-IKKα, c-Jun, p-c-Jun, MKP, p-MKP, VCAM1, ICAM1, CXCL1, PPARγ, and Adipor2. Compared with the model group, the TDN group displayed significantly increased mRNA expression of c-Jun, MKP, CXCL1, PPARγ, and Adipor2 and significantly decreased mRNA expression of ICAM1. Compared with the model group, the TDN group exhibited significantly increased protein expression of MKP and significantly decreased protein expression of p-ERK1/2, p-38, p-JNK, p-IKKα, p-c-Jun, VCAM1, ICAM1, and PPARγ. Our results indicated that TDN could treat GA by influencing the MAPK-PPARγ signaling pathway.

Effects of in utero androgen excess and metformin treatment on hepatic functions

This study aimed to evaluate the role of prenatal hyperandrogenization in liver functions and the extent of metformin as treatment. Pregnant rats were hyperandrogenized with subcutaneous testosterone (1mg/rat) between 16 and 19 of pregnancy. Prenatally hyperandrogenized (PH) female offspring displayed, at the adult life, two phenotypes; a PH irregular ovulatory phenotype (PHiov) and a PH anovulatory (PHanov) phenotype. From day 70 to the moment of sacrifice (90 days of age), 50% of the animals of each group received a daily oral dose of 50 mg/kg of metformin. We found that both PH phenotypes displayed a hepatic disruptions of insulin and glucose pathway and that metformin treatment reversed some of these alterations in a specific-phenotype manner. Our findings show, for the first time, that androgen excess in utero promotes hepatic dysfunctions and that metformin treatment is able to specifically reverse those hepatic alterations and sheds light on the possible mechanisms of metformin action.

Metformin attenuates cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells

Metformin is widely used as an oral hypoglycemic drug in the management of type 2 diabetes mellitus. This study evaluated the possible protective effects of metformin against cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells. Two different doses of metformin (50 and 100 mg/kg b.w.) were administered orally to experimental animals for seven consecutive days. On the seventh day, the rats were exposed to cisplatin (5 mg/kg, i.p.) 1 h after the last oral metformin administration. Rats in the control group were treated orally with 10 ml/kg PBS for 7 consecutive days and a single intraperitoneal injection of saline (0.9%) on the 7th day. The antagonistic effects of metformin against cisplatin were evaluated using micronucleus assay, reactive oxygen species (ROS) level analysis, hematological analysis, and flow cytometry. Treatment with 50 and 100 mg/kg metformin before cisplatin injection produced a significant reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after cisplatin treatment with a corresponding increase in the PCE/(PCE + NCE) ratio. Moreover, metformin markedly elevated the levels of both red and white blood cells in peripheral blood and decreased the percentage of apoptotic cells and the ROS level in bone marrow cells of rats treated with cisplatin. The data suggest that metformin has potential chemoprotective properties in rat bone marrow after cisplatin treatment, which support its candidature as a potential chemoprotective agent for cancer patients undergoing chemotherapy.

Metformin modifies disparity in hepatocellular carcinoma incidence in men with type 2 diabetes but without chronic liver diseases

Background

We assessed racial/ethnic disparity in hepatocellular carcinoma (HCC) incidence among men with type 2 diabetes (T2D) but without chronic liver diseases (CLD), and whether metformin use modified the disparity.

Methods

Study cohort: the nationwide Veterans Administration Health Care System electronic medical records among 40‐89 years old men with T2D; without CLD, cancer, cardiovascular or renal diseases previously; insulin and thiazolidinedione naive. Logistic regression analyses compared HCC incidence between race/ethnicity groups under no metformin use adjusted for covariates and inverse propensity score weights (IPSW) for race/ethnicity. The generalizability technique integrated with IPSW was incorporated to compare covariates adjusted odds ratios (aOR) of HCC associated with metformin use among race/ethnicity groups.

Results

Study cohort: N = 84 433; 79.47% non‐Hispanic white (NHW), 15.5% non‐Hispanic African American (NHAA), 5.03% Hispanics; 36.76% metformin users; follow‐up 6.10 ± 2.87 years; age 67.8 ± 9.8 years, HbA1c 6.57 ± 0.98%; 0.14% HCC cases. Under no metformin use, HCC incidence was lower for NHAA vs NHW (aOR = 0.60 [0.40‐0.92]), similar between NHW and Hispanics. Metformin was associated with reduced HCC risk: aOR = 0.57 (0.40‐0.81) for NHW; aOR = 0.35 (0.25‐0.47) for NHAA; aOR = 0.31 (0.22‐0.43) for Hispanics. Metformin dose >1000 mg/d was neutral for NHW; less effective for NHAA (P = 0.02); more effective for Hispanics (P = 0.002).

Conclusions

In men with T2D but without CLD nor metformin use, HCC incidence was lower for NHAA compared to NHW or Hispanics; similar between NHW and Hispanics. Metformin use reduced HCC risk and modified the race/ethnicity disparity.

Impact

Metformin's heterogeneous HCC prevention effect elucidates potential interventions to modify HCC disparity in patients with T2D.

Hepatoprotective activity of metformin: A new mission for an old drug?

Metformin, as a dimethyl biguanide prescribed as the first-line medication for treatment of type 2 diabetes mellitus, is one of the most frequently used drugs, worldwide. However, the beneficial effects of metformin are not limited to insulin sensitizing and blood glucose lowering effects as recent clinical trials deciphered lower cancer risk in metformin users. In addition, metformin protected the liver against chemical or viral hepatotoxicants through various mechanisms including activation of AMPK via inhibition of mitochondrial complex I, inhibition of mitogen activated protein kinase (MAPK) and inhibition of Smads phosphorylation. Clinical trials are under way to assess possible additive effects of metformin when co-administered along with the standard regimen for hepatocellular carcinoma (HCC) treatment. This review outlines the molecular mechanisms behind protective activity of metformin against different liver diseases.

Metformin as a Radiation Modifier; Implications to Normal Tissue Protection and Tumor Sensitization

BACKGROUND

Nowadays, ionizing radiation is used for several applications in medicine, industry, agriculture, and nuclear power generation. Besides the beneficial roles of ionizing radiation, there are some concerns about accidental exposure to radioactive sources. The threat posed by its use in terrorism is of global concern. Furthermore, there are several side effects to normal organs for patients who had undergone radiation treatment for cancer. Hence, the modulation of radiation response in normal tissues was one of the most important aims of radiobiology. Although, so far, several agents have been investigated for protection and mitigation of radiation injury. Agents such as amifostine may lead to severe toxicity, while others may interfere with radiation therapy outcomes as a result of tumor protection. Metformin is a natural agent that is well known as an antidiabetic drug. It has shown some antioxidant effects and enhances DNA repair capacity, thereby ameliorating cell death following exposure to radiation. Moreover, through targeting endogenous ROS production within cells, it can mitigate radiation injury. This could potentially make it an effective radiation countermeasure. In contrast to other radioprotectors, metformin has shown modulatory effects through induction of several genes such as AMPK, which suppresses reduction/ oxidation (redox) reactions, protects cells from accumulation of unrepaired DNA, and attenuates initiation of inflammation as well as fibrotic pathways. Interestingly, these properties of metformin can sensitize cancer cells to radiotherapy.

CONCLUSION

In this article, we aimed to review the interesting properties of metformin such as radioprotection, radiomitigation and radiosensitization, which could make it an interesting adjuvant for clinical radiotherapy, as well as an interesting candidate for mitigation of radiation injury after a radiation disaster.

Fucosterol Protects against Concanavalin A-Induced Acute Liver Injury: Focus on P38 MAPK/NF-κB Pathway Activity

Objective

Fucosterol is derived from the brown alga Eisenia bicyclis and has various biological activities, including antioxidant, anticancer, and antidiabetic properties. The aim of this study was to investigate the protective effects of fucosterol pretreatment on Concanavalin A- (ConA-) induced acute liver injury in mice, and to understand its molecular mechanisms.

Materials and Methods

Acute liver injury was induced in BALB/c mice by ConA (25 mg/kg), and fucosterol (dissolved in 2% DMSO) was orally administered daily at doses of 25, 50, and 100 mg/kg. The levels of hepatic necrosis, apoptosis, and autophagy associated with inflammatory cytokines were measured at 2, 8, and 24 h.

Results

Fucosterol attenuated serum liver enzyme levels and hepatic necrosis and apoptosis induced by TNF-α, IL-6, and IL-1β. Fucosterol also inhibited apoptosis and autophagy by upregulating Bcl-2, which decreased levels of functional Bax and Beclin-1. Furthermore, reduced P38 MAPK and NF-κB signaling were accompanied by PPARγ activation.

Conclusion

This study showed that fucosterol could alleviate acute liver injury induced by ConA by inhibiting P38 MAPK/PPARγ/NF-κB signaling. These findings highlight that fucosterol is a promising potential therapeutic agent for acute liver injury.

Metformin-like antidiabetic, cardio-protective and non-glycemic effects of naringenin: Molecular and pharmacological insights

Metformin is a widely used drug for the treatment of type 2 diabetes (T2D). Its blood glucose-lowering effects are initially due to inhibition of hepatic glucose production and increased peripheral glucose utilization. Metformin has also been shown to have several beneficial effects on cardiovascular risk factors and it is the only oral antihyperglycaemic agent thus far associated with decreased macrovascular complications in patients with diabetes. Adenosine Monophosphate Activated-Protein Kinase (AMPK) is a major cellular regulator of lipid and glucose metabolism. Recent evidence shows that pharmacological activation of AMPK improves blood glucose homeostasis, lipid profiles, blood pressure and insulin-resistance making it a novel therapeutic target in the treatment of T2D. Naringenin a flavonoid found in high concentrations as its glycone naringin in citrus fruits, has been reported to have antioxidant, antiatherogenic, anti- dyslipidemic and anti-diabetic effects. It has been shown that naringenin exerts its anti-diabetic effects by inhibition of gluconeogenesis through upregulations of AMPK hence metformin-like effects. Naringin has further been shown to have non-glycemic affects like metformin that mitigate inflammation and cell proliferation. This review evaluates the potential of naringenin as anti-diabetic, anti-dyslipidemic anti-inflammatory and antineoplastic agent similar to metformin and proposes its further development for therapeutic use in clinical practice.