Metformin Attenuates Cyclosporine A-induced Renal Fibrosis in Rats

Delaying Renal Aging: Metformin Holds Promise as a Potential Treatment

Given the rapid aging of the population, age-related diseases have become an excessive burden on global health care. The kidney, a crucial metabolic organ, ages relatively quickly. While the aging process itself does not directly cause kidney damage, the physiological changes that accompany it can impair the kidney's capacity for self-repair. This makes aging kidneys more susceptible to diseases, including increased risks of chronic kidney disease and end-stage renal disease. Therefore, delaying the progression of renal aging and preserving the youthful vitality of the kidney are crucial for preventing kidney diseases. However, effective strategies against renal aging are still lacking due to the underlying mechanisms of renal aging, which have not been fully elucidated. Accumulating evidence suggests that metformin has beneficial effects in mitigating renal aging. Metformin has shown promising anti-aging results in animal models but has not been tested for this purpose yet in clinical trials. These findings indicate the potential of metformin as an anti-renal aging drug. In this review, we primarily discuss the characteristics and mechanisms of kidney aging and the potential effects of metformin against renal aging.

Rationale and Design of a Phase 2, Double-blind, Placebo-Controlled, Randomized Trial Evaluating AMP Kinase-Activation by Metformin in Focal Segmental Glomerulosclerosis

Introduction

Focal segmental glomerulosclerosis (FSGS), the most common primary glomerular disease leading to end-stage kidney disease (ESKD), is characterized by podocyte injury and depletion, whereas minimal change disease (MCD) has better outcomes despite podocyte injury. Identifying mechanisms capable of preventing podocytopenia during injury could transform FSGS to an "MCD-like" state. Preclinical data have reported conversion of an MCD-like injury to one with podocytopenia and FSGS by inhibition of AMP-kinase (AMPK) in podocytes. Conversely, in FSGS, AMPK-activation using metformin (MF) mitigated podocytopenia and azotemia. Observational studies also support beneficial effects of MF on proteinuria and chronic kidney disease (CKD) outcomes in diabetes. A randomized controlled trial (RCT) to test MF in podocyte injury with FSGS has not yet been conducted.

Methods

We report the rationale and design of phase 2, double-blind, placebo-controlled RCT evaluating the efficacy and safety of MF as adjunctive therapy in FSGS. By randomizing 30 patients with biopsy-confirmed FSGS to MF or placebo (along with standard immunosuppression), we will study mechanistic biomarkers that correlate with podocyte injury or depletion and evaluate outcomes after 6 months. We specifically integrate novel urine, blood, and tissue markers as surrogates for FSGS progression along with unbiased profiling strategies.

Results and Conclusion

Our phase 2 trial will provide insight into the potential efficacy and safety of MF as adjunctive therapy in FSGS-a crucial step to developing a larger phase 3 study. The mechanistic assays here will guide the design of other FSGS trials and contribute to understanding AMPK activation as a potential therapeutic target in FSGS. By repurposing an inexpensive agent, our results will have implications for FSGS treatment in resource-poor settings.

Immunolocalization of Matrix Metalloproteinases 2 and 9 and Their Inhibitors in the Hearts of Rats Treated with Immunosuppressive Drugs-An Artificial Intelligence-Based Digital Analysis

BACKGROUND

Immunosuppressive agents represent a broad group of drugs, such as calcineurin inhibitors, mTOR inhibitors, and glucocorticosteroids, among others. These drugs are widely used in a number of conditions, but lifelong therapy is crucial in the case of organ recipients to prevent rejection. To further increase the safety and efficacy of these agents, their off-target mechanisms of action, as well as processes underlying the pathogenesis of adverse effects, need to be thoroughly investigated. The aim of this study was to examine the impact of various combinations of cyclosporine/tacrolimus/mycophenolate with rapamycin and steroids (CRG, TRG, MRG), on the morphology and morphometry of rats' cardiomyocytes, together with the presence of cardiac collagen and the immunoexpression of MMPs and TIMPs.

METHODS

Twenty-four rats were divided into four groups receiving different immunosuppressive regiments. After six months of treatment, the hearts were collected and analyzed.

RESULTS

Cardiomyocytes from the CRG cohorts demonstrated the most pronounced morphological alterations. In addition, chronic immunosuppression reduced the width and length of cardiac cells. However, immunosuppressive therapy did not alter the presence of cardiac collagen fibers. Nevertheless, we observed significant alterations regarding MMP/TIMP homeostasis.

CONCLUSIONS

Chronic immunosuppression seems to disturb the MMP/TIMP balance in aspects of immunolocalization in the hearts of rats. Further studies are required to analyze other mechanisms and pathways affected by the use of immunosuppressants.

Targeting Senescent Cells as Therapy for CKD

Senescent cells accumulate in the kidney with aging, after acute and chronic injuries, and are present in increased numbers in deteriorating kidney transplants. Senescent cells have undergone permanent cell cycle arrest and release many proinflammatory cytokines/chemokines and profibrotic factors: the senescence-associated secretory phenotype. Recent work from several groups including our own has shown that senescent cells play a causative role in progression of kidney disease. Experimental evidence also indicates that targeting senescent cells has potential to alter the renal regenerative response, reducing progressive fibrosis and improving functional recovery after injury. Research and clinical interest is focused on understanding how accumulating chronic senescent cells link acute injury to progressive fibrosis, dysfunction, and mortality in human CKD. In this review, we outline current protocols for the identification of how senescent cells are identified in vitro and in vivo . We discuss the proposed mechanisms of actions of first-generation senolytic and senomorphic agents, such as ABT-263 (navitoclax) which targets the BCL2 family of survival factors, and senomorphic agents such as metformin which targets aspects of the senescence-associated secretory phenotype. We also review that emerging technologies, such as nanocarriers, are now being developed to have safer delivery systems for senolytics, greater specificity, fewer off-target effects, and less toxicity. Other methods of senescent cell elimination being developed target various immune evasion tactics displayed by these cells. By understanding the role of senescence in kidney homeostasis and disease, developing new, targeted compounds and the tools to allow their efficacy to be charted noninvasively, it should become possible for senolytic treatments to move from the bench to bedside.

Kidney lipid dysmetabolism and lipid droplet accumulation in chronic kidney disease

Chronic kidney disease (CKD) is a global health problem with rising incidence and prevalence. Among several pathogenetic mechanisms responsible for disease progression, lipid accumulation in the kidney parenchyma might drive inflammation and fibrosis, as has been described in fatty liver diseases. Lipids and their metabolites have several important structural and functional roles, as they are constituents of cell and organelle membranes, serve as signalling molecules and are used for energy production. However, although lipids can be stored in lipid droplets to maintain lipid homeostasis, lipid accumulation can become pathogenic. Understanding the mechanisms linking kidney parenchymal lipid accumulation to CKD of metabolic or non-metabolic origin is challenging, owing to the tremendous variety of lipid species and their functional diversity across different parenchymal cells. Nonetheless, multiple research reports have begun to emphasize the effect of dysregulated kidney lipid metabolism in CKD progression. For example, altered cholesterol and fatty acid metabolism contribute to glomerular and tubular cell injury. Newly developed lipid-targeting agents are being tested in clinical trials in CKD, raising expectations for further therapeutic development in this field.

Comparative effectiveness of metformin versus sulfonylureas on kidney function decline or death among patients with reduced kidney function: a retrospective cohort study

BACKGROUND

Diabetes often causes kidney disease. In this study, we sought to evaluate if metformin use was associated with death or kidney events in patients with diabetes and concurrent reduced kidney function.

METHODS

We used data from the Veterans Health Administration, Medicare and National Death Index databases to assemble a national retrospective cohort of veterans who were using metformin or sulfonylureas from 2001 through 2016 and who began follow-up at an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m². The primary composite outcome was a kidney event (i.e., 40% decline in eGFR or end-stage renal disease) or death. The secondary outcome was a kidney event (eGFR decline or end-stage renal disease). We weighted the cohort using propensity scores and used Cox proportional models to estimate the cause-specific hazard of outcomes and of treatment nonpersistence as a competing risk. We stratified follow-up into 2 periods, namely the first 360 days from the start of follow-up, and 361 days and beyond.

RESULTS

In the first 360 days, the propensity score-weighted cohort included 24 883 patients who used metformin and 24 998 who used sulfonylureas. There were 33.5 (95% confidence interval [CI] 30.9-36.3) and 43.0 (95% CI 40.1-46.0) deaths or kidney events per 1000 person-years for patients who used metformin or sulfonylureas, respectively (hazard ratio [HR] 0.78, 95% CI 0.71-0.85). For the secondary outcome of kidney events, the HR was 0.94 (95% CI 0.67-1.33). In the second period from 361 days onward, the primary outcome event rate was 26.5 (95% CI 24.7-28.5) per 1000 person-years for those who used metformin, compared with 36.3 (95% CI 34.2-38.6) per 1000 person-years for those who used sulfonylureas (HR 0.73, 95% CI 0.67-0.79). Results were consistent for kidney events alone (HR 0.73, 95% CI 0.59-0.91).

INTERPRETATION

Metformin use for 361 days or longer after reaching an eGFR of less than 60 mL/min/1.73 m² was associated with decreased likelihood of kidney events or death in patients with diabetes, compared with use of sulfonylureas. Metformin provided end-organ protection, in addition to glucose control.

Attenuated Risk Association of End-Stage Kidney Disease with Metformin in Type 2 Diabetes with eGFR Categories 1-4

Type 2 diabetes (T2D)-associated end-stage kidney disease (ESKD) is a global burden, while the renoprotective effects of metformin remain controversial. In a population-based cohort (2002-2018) including 96,643 patients with T2D observed for 0.7 million person-years, we estimated the risk association of metformin and its dose-relationship with ESKD in a propensity-score overlap-weighting (PS-OW) cohort by eGFR categories. Amongst 96,643, 83,881 (86.8%) had eGFR-G1/G2 (≥60 mL/min/1.73 m2), 8762 (9.1%) had eGFR-G3a (≥45-60 mL/min/1.73 m2), 3051 (3.2%) had eGFR-G3b (≥30-45 mL/min/1.73 m2), and 949 (1.0%) had eGFR-G4 (≥15-30 mL/min/1.73 m2). The respective proportions of metformin users in these eGFR categories were 95.1%, 81.9%, 53.8%, and 20.8%. In the PS-OW cohort with 88,771 new-metformin and 7872 other oral glucose-lowering-drugs (OGLDs) users, the respective incidence rates of ESKD were 2.8 versus 22.4/1000 person-years. Metformin use associated with reduced risk of ESKD (hazard ratio (HR) = 0.43 [95% CI: 0.35-0.52] in eGFR-G1/G2, 0.64 [0.52-0.79] in eGFR-G3a, 0.67 [0.56-0.80] in eGFR-G3b, and 0.63 [0.48-0.83] in eGFR-G4). Metformin use was associated with reduced or neutral risk of major adverse cardiovascular events (MACE) (7.2 versus 16.0/1000 person-years) and all-cause mortality (14.6 versus 65.1/1000 person-years). Time-weighted mean daily metformin dose was 1000 mg in eGFR-G1/G2, 850 mg in eGFR-G3a, 650 mg in eGFR-G3b, and 500 mg in eGFR-G4. In a subcohort of 14,766 patients observed for 0.1 million person-years, the respective incidence rates of lactic acidosis and HR in metformin users and non-users were 42.5 versus 226.4 events/100,000 person-years (p = 0.03) for eGFR-G1/G2 (HR = 0.57, 0.25-1.30) and 54.5 versus 300.6 events/100,000 person-years (p = 0.01) for eGFR-G3/G4 (HR = 0.49, 0.19-1.30). These real-world data underscore the major benefits and low risk of lactic acidosis with metformin use down to an eGFR of 30 mL/min/1.73 m2 and possibly even 15 mL/min/1.73 m2, while reinforcing the importance of dose adjustment and frequent monitoring of eGFR.

A role for metformin in the treatment of Dupuytren disease?

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

Protection by metformin against severe Covid-19: an in-depth mechanistic analysis

Since the outbreak of Covid-19, several observational studies on diabetes and Covid-19 have reported a favourable association between metformin and Covid-19-related outcomes in patients with type 2 diabetes mellitus (T2DM). This is not surprising since metformin affects many of the pathophysiological mechanisms implicated in SARS-CoV-2 immune response, systemic spread and sequelae. A comparison of the multifactorial pathophysiological mechanisms of Covid-19 progression with metformin's well-known pleiotropic properties suggests that the treatment of patients with this drug might be particularly beneficial. Indeed, metformin could alleviate the cytokine storm, diminish virus entry into cells, protect against microvascular damage as well as prevent secondary fibrosis. Although our in-depth analysis covers many potential metformin mechanisms of action, we want to highlight more particularly its unique microcirculatory protective effects since worsening of Covid-19 disease clearly appears as largely due to severe defects in the structure and functioning of microvessels. Overall, these observations confirm that metformin is a unique, pleiotropic drug that targets many of Covid-19′s pathophysiology processes in a diabetes-independent manner.

Metformin: Expanding the Scope of Application-Starting Earlier than Yesterday, Canceling Later

Today the area of application of metformin is expanding, and a wealth of data point to its benefits in people without carbohydrate metabolism disorders. Already in the population of people leading an unhealthy lifestyle, before the formation of obesity and prediabetes metformin smooths out the adverse effects of a high-fat diet. Being prescribed at this stage, metformin will probably be able to, if not prevent, then significantly reduce the progression of all subsequent metabolic changes. To a large extent, this review will discuss the proofs of the evidence for this. Another recent important change is a removal of a number of restrictions on its use in patients with heart failure, acute coronary syndrome and chronic kidney disease. We will discuss the reasons for these changes and present a new perspective on the role of increasing lactate in metformin therapy.

Regulation of transforming growth factor-β signalling by SUMOylation and its role in fibrosis

Fibrosis is an abnormal healing process that only repairs the structure of an organ after injury and does not address damaged functions. The pathogenesis of fibrosis is multifactorial and highly complex; numerous signalling pathways are involved in this process, with the transforming growth factor-β (TGF-β) signalling pathway playing a central role. TGF-β regulates the generation of myofibroblasts and the epithelial-mesenchymal transition by regulating transcription and translation of downstream genes and precisely regulating fibrogenesis. The TGF-β signalling pathway can be modulated by various post-translational modifications, of which SUMOylation has been shown to play a key role. In this review, we focus on the function of SUMOylation in canonical and non-canonical TGF-β signalling and its role in fibrosis, providing promising therapeutic strategies for fibrosis.

Metformin attenuates the epithelial-mesenchymal transition of lens epithelial cells through the AMPK/TGF-β/Smad2/3 signalling pathway

Posterior capsule opacification (PCO) is a common ocular fibrosis disease related to the epithelial-mesenchymal transition (EMT) of human lens epithelial cells (HLECs). However, safe and effective drugs that prevent or treat PCO are lacking. Metformin (Mtf) has been used to treat fibrosis-related diseases affecting many organs and tissues, but its effect on ocular fibrosis-related diseases is unclear. We investigated whether Mtf can inhibit EMT and fibrosis in HLECs to prevent and treat PCO and elucidated the potential molecular mechanism. Here, we established an HLEC model of TGF-β-induced EMT and found that 400 μM Mtf inhibited vertical and lateral migration and EMT-related gene and protein expression in HLECs. Smad2/3 are downstream molecules of TGF-β that enter the nucleus to regulate EMT-related gene expression during the occurrence and development of PCO. We revealed that Mtf suppressed TGF-β-induced Smad2/3 phosphorylation and nuclear translocation. Mtf induces AMP-activated protein kinase (AMPK) phosphorylation. In this study, we found that Mtf induced the activation of AMPK phosphorylation in HLECs. To further explore the mechanism of Mtf, we pretreated HLECs with Compound C (an AMPK inhibitor) to repeat the above experiments and found that Compound C abolished the inhibitory effect of Mtf on HLEC EMT and the TGF-β/Smad2/3 signalling pathway. Thus, Mtf targets AMPK phosphorylation to inhibit the TGF-β/Smad2/3 signalling pathway and prevent HLEC EMT. Notably, we first illustrated the AMPK/TGF-β/Smad2/3 signalling pathway in HLECs, which may provide a new therapeutic strategy for PCO.

Panax Ginseng C.A.Mey. as Medicine: The Potential Use of Panax Ginseng C.A.Mey. as a Remedy for Kidney Protection from a Pharmacological Perspective

Panax ginseng C.A.Mey. has been widely consumed as food/diet supplements from natural sources, and its therapeutic properties have also aroused widespread concern. Therapeutic properties of Panax ginseng C.A.Mey. such as anti-inflammatory, ameliorating chronic inflammation, enhancing the immunity, resisting the oxidation again, and regulating the glucose and lipid metabolism have been widely reported. Recent years, lots of interesting studies have reported the potential use of Panax ginseng C.A.Mey. in the management of DKD. DKD has become the leading cause of end-stage renal disease worldwide, which increases the risk of premature death and poses a serious financial burden. Although DKD is somehow controllable with different drugs such as Angiotensin-Converting Enzyme Inhibitors (ACEI), Angiotensin Receptor Blockers (ARB) and lowering-glucose agents, modern dietary changes associated with DKD have facilitated research to assess the preventive and therapeutic merits of diet supplements from natural sources as medicine including Panax ginseng C.A.Mey. Findings from many scientific evidences have suggested that Panax ginseng C.A.Mey. can relieve the pathological status in cellular and animal models of DKD. Moreover, a few studies showed that alleviation of clinical phenotype such as reducing albuminuria, serum creatinine and renal anemia in DKD patients after application or consumption of Panax ginseng C.A.Mey.. Therefore, this review aims to discuss the effectiveness of Panax ginseng C.A.Mey. as medicine for targeting pathological phenotypes in DKD from a pharmacological perspective. This review will provide new insights into the potential understanding use of Panax ginseng C.A.Mey. in the management of DKD in clinical settings.

Inhibition of Glycogen Synthase Kinase 3β Alleviates Chronic Renal Allograft Dysfunction in Rats

BACKGROUND

Chronic renal allograft dysfunction (CRAD) is a major condition that impedes the long-term survival of renal allografts. However, the mechanism of CRAD is obscure, and the effective strategies for controlling the progression of CRAD are lacking. The present study used a CRAD rat model to assess the effect of glycogen synthase kinase 3β (GSK-3β) inhibition on the development of CRAD.

METHODS

A classical F334-to-LEW orthotopic renal transplantation was performed on the CRAD group. The treatment group was treated with the GSK-3β inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione for 12 consecutive weeks following renal transplantation. The study included uninephrectomized F344 and Lewis rats as control subjects. Twelve weeks post surgery, the rats were retrieved for analysis of renal function, urine protein levels, histological, immunohistochemical, and molecular biological parameters.

RESULTS

Administration of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione inactivated GSK-3β and thereby improved renal function, attenuated proteinuria, and reduced renal tissue damage in CRAD rats. Besides, inactivation of GSK-3β inhibited nuclear factor-κB activation, macrophage infiltration, and expression of multiple proinflammatory cytokines/chemokines. Inhibition of GSK-3β also decreased the levels of malondialdehyde, increased superoxide dismutase levels, upregulated the expression of heme oxygenase-1 and NAD(P)H quinone oxidoreductase-1, and enhanced nuclear translocation of nuclear factor erythroid 2-related factor 2 in the kidneys of CRAD rats.

CONCLUSIONS

Inhibition of GSK-3β attenuates the development of CRAD by inhibiting inflammation and oxidant stress. Thus, GSK-3β inhibition may represent a potential therapeutic strategy for the prevention and treatment of CRAD.

Mechanism and application of metformin in kidney diseases: An update

Metformin is an oral antihyperglycemic drug widely used to treat type 2 diabetes mellitus (T2DM), acting via indirect activation of 5' Adenosine monophosphate-activated Protein Kinase (AMPK). Beyond the anti-diabetic effect, accumulative pieces of evidence have revealed that metformin also everts a beneficial effect in diverse kidney diseases. In various acute kidney diseases (AKI) animal models, metformin protects renal tubular cells from inflammation, apoptosis, reactive oxygen stress (ROS), endoplasmic reticulum (ER) stress, epithelial-mesenchymal transition (EMT) via AMPK activation. In diabetic kidney disease (DKD), metformin also alleviates podocyte loss, mesangial cells apoptosis, and tubular cells senescence through AMPK-mediated signaling pathways. Besides, metformin inhibits cystic fibrosis transmembrane conductance regulator (CFTR)-mediated fluids secretion and the mammalian target of rapamycin (mTOR)-involved cyst formation negatively regulated by AMPK in autosomal dominant polycystic kidney disease (APDKD). Furthermore, metformin also contributes to the alleviation of urolithiasis and renal cell carcinoma (RCC). As the common pathway for chronic kidney disease (CKD) progressing towards end-stage renal disease (ESRD), renal fibrosis is ameliorated by metformin, to a great extent dependent on AMPK activation. However, clinical data are not always consistent with preclinical data, some clinical investigations showed the unmeaningful even detrimental effect of metformin on T2DM patients with kidney diseases. Most importantly, metformin-associated lactic acidosis (MALA) is a vital issue restricting the application of metformin. Thus, we conclude the application of metformin in kidney diseases and uncover the underlying molecular mechanisms in this review.

Metformin Attenuates Renal Fibrosis in a Mouse Model of Adenine-Induced Renal Injury Through Inhibiting TGF-β1 Signaling Pathways

It is well-known that all progressive chronic kidney disease (CKD) is pathologically characterized by tubulointerstitial fibrosis process. Multiple studies have shown the critical role of inflammation and fibrosis in the development of CKD. Hence strategies that target inflammatory and fibrotic signaling pathways may provide promising opportunities to protect against renal fibrosis. Metformin has been used as the first-line glucose-lowering agent to treat patients with type 2 diabetes mellitus (T2DM) for over 50 years. Accumulating evidence suggests the potential for additional therapeutic applications of metformin, including mitigation of renal fibrosis. In this study, the anti-fibrotic effects of metformin independent of its glucose-lowering mechanism were examined in an adenine -induced mouse model of CKD. Expressions of inflammatory markers MCP-1, F4/80 and ICAM, fibrotic markers type IV collagen and fibronectin, and the cytokine TGF-β1 were increased in adenine-induced CKD when compared to control groups and significantly attenuated by metformin treatment. Moreover, treatment with metformin inhibited the phosphorylation of Smad3, ERK1/2, and P38 and was associated with activation of the AMP-activated protein kinase (AMPK) in the kidneys of adenine-treated mice. These results indicate that metformin attenuates adenine-induced renal fibrosis through inhibition of TGF-β1 signaling pathways and activation of AMPK, independent of its glucose-lowering action.

Metformin and Fibrosis: A Review of Existing Evidence and Mechanisms

Fibrosis is a physiological response to organ injury and is characterized by the excessive deposition of connective tissue components in an organ, which results in the disruption of physiological architecture and organ remodeling, ultimately leading to organ failure and death. Fibrosis in the lung, kidney, and liver accounts for a substantial proportion of the global burden of disability and mortality. To date, there are no effective therapeutic strategies for controlling fibrosis. A class of metabolically targeted chemicals, such as adenosine monophosphate-activated protein kinase (AMPK) activators and peroxisome proliferator-activated receptor (PPAR) agonists, shows strong potential in fighting fibrosis. Metformin, which is a potent AMPK activator and is the only recommended first-line drug for the treatment of type 2 diabetes, has emerged as a promising method of fibrosis reduction or reversion. In this review, we first summarize the key experimental and clinical studies that have specifically investigated the effects of metformin on organ fibrosis. Then, we discuss the mechanisms involved in mediating the antifibrotic effects of metformin in depth.

Cyclosporine A induces kidney dysfunction by the alteration of molecular mediators involved in slit diaphragm regulation and matrix metalloproteins: the mitigating effect of curcumin

BACKGROUND

This research aimed at investigating the cyclosporine A intake impact with/without curcumin on podocyte protein gene expressions and matrix metalloproteins (MMPs) changes in rat kidney.

METHODS

Thirty-two Wistar male rats were assigned to the control, sham, cyclosporine A, and cyclosporine A with curcumin groups.

RESULTS

A significant increase was observed in CD2AP, ACTN4, podocin and also MMP9 and 2, cystatin C levels in the cyclosporine A group following treatment for four weeks, whereas a decrease was found in nephrin gene expression than the control group. In addition, a significant reduction was observed in the cyclosporine A group in glomerular filtration rate (GFR), urine creatinine, and increased plasma creatinine levels than the control group. Using curcumin plus cyclosporine A ameliorated gene expression alterations and increased the reduced amount of GFR, urine urea, and creatinine while reducing the increased plasma cystatine C, urea, and creatinine levels compared with the cyclosporine A group.

CONCLUSION

Accordingly, cyclosporine A-induced kidney abnormalities are possibly associated with changes in podocyte intra- and extra-cellular protein gene expression that influence the quality of filtrated fluid via altering the foot process shape and slit diaphragm size. Finally, such impacts are reduced via curcumin as an antioxidant and anti-inflammatory compound.

Metformin and silymarin afford protection in cyclosporine A induced hepatorenal toxicity in rat by modulating redox status and inflammation

The use of cyclosporine A (CsA) as an immunosuppressive agent is often limited owing to its hepatotoxic and nephrotoxic properties. The present study was designed to evaluate the protective effect of metformin and silymarin in a rat model of CsA induced hepatorenal toxicity. The study included seven groups of Wistar albino rats (n = 6 per group): normal control, experimental control (CsA alone, 25 mg/kg), CsA + metformin (50 and 500 mg/kg), CsA + silymarin (50 and 200 mg/kg) and CsA + vitamin E (100 mg/kg). All the drugs were given daily for a period of 21 days by oral gavage and their effect was evaluated on serum levels of organ function markers (serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase, bilirubin, urea/blood urea nitrogen, creatinine), markers of oxidative stress (thiobarbituric acid reactive substances, glutathione, superoxide dismutase), inflammation (nitrite, myeloperoxidase, tumour necrosis factor-alpha, prostaglandin E₂ ), apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labelling positivity) in addition to tissue histology, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) immunoreactivity. Administration of metformin and silymarin along with CsA ameliorated functional damage to liver and kidneys in a dose-dependent manner. Significant and comparable improvement in the tissue levels of oxidative stress, inflammation, apoptotic markers was also observed following treatment with both the test drugs. Normalization of histology scores, as well as COX-2 and iNOS immunoreactivity scores, further strengthened these findings. The hepatoprotective and nephroprotective effects of metformin and silymarin were comparable and matched with that of reference drug, vitamin E. The findings of the present study suggest that both metformin and silymarin have a potential for clinical use in patients receiving long-term CsA treatment to maintain their liver and kidney functions.