Protective effects of leflunomide on renal lesions in a rat model if diabetic nephropathy

A novel role of Nano selenium and sildenafil on streptozotocin-induced diabetic nephropathy in rats by modulation of inflammatory, oxidative, and apoptotic pathways

AIMS

The present study aimed to investigate the effect of nano selenium, sildenafil, and their combination on inflammation, oxidative stress, and apoptosis in streptozotocin-induced diabetic nephropathy in rats. Herein, a new anti-inflammatory pathway for sildenafil as a high-mobility group box (HMGB1) inhibitor was proposed using the molecular docking technique.

MATERIALS AND METHODS

Rats were divided into 7 groups: normal control, control nano selenium, control sildenafil, control diabetic, diabetic+ nano selenium, diabetic+ sildenafil, diabetic+ nano selenium+ sildenafil. The effects of drugs were evaluated by measuring serum urea, creatinine, lactate dehydrogenase (LDH), levels of tumor necrosis factor-alpha (TNF-α), Interleukin 1 beta (IL-1β), HMGB1, receptor advanced glycation end product (RAGE), malondialdehyde (MDA), thioredoxin reductase (TrxR) by biochemical assays, nuclear factor-kappa b (NF-κB), toll-like receptor (TLR4) by immunohistochemistry, gene expressions of caspase 3 and monocyte chemoattractant protein (MCP-1) besides histopathological investigations of renal cells.

KEY FINDINGS

Results showed beneficial effects of 8 weeks of treatment by nano selenium and sildenafil supported by improvement in kidney function, histopathological changes, and reduction in all of these parameters. These results supported molecular docking that indicated sildenafil had a high binding score and interactions with the HMGB1 receptor.

SIGNIFICANCE

The current study demonstrated a renoprotective effect of nano‑selenium and sildenafil by interfering at multiple pathways, especially the HMGB1/NF-κB signaling pathway.

Retrospective analysis of leflunomide and low-dose methylprednisolone for the treatment of diabetic nephropathy combined with membranous nephropathy

Diabetic kidney disease (DKD) combined with Membranous Nephropathy (MN) was observed in some patients with the increasing of Diabetic patients. However, no treatment guidelines are available for DKD combined with MN. In this study, we for the first time analyzed the safety and efficacy of leflunomide (LEF) combined with low-dose glucocorticoid methylprednisolone (MP) in the treatment of DKD with MN. We retrospectively collected the clinical data of patients with the highest number of DKD combined with MN diagnosed by renal biopsy between December 2016 and December 2020. The inclusion criteria were a history of diabetes for more than 20 months, no glucocorticoid therapy or immunosuppressant therapy for at least 6 months, urine protein level greater than 3.5 g, and a follow-up time of 16 months. In addition to conservative treatment, the patients received LEF monotherapy (LEF, n = 38) or LEF combined with low-dose methylprednisolone (LEF+MP, n = 26). After 16 months of treatment, the complete remission rate was 2.6%, and the remission rate was 15.8% in the LEF group; in the LEF+MP group, the complete remission rate and the remission rate were 23.1% and 34.6%, respectively. At month 16, the urine protein level was lower than the baseline value in both groups (p < 0.05) and was significantly lower in the LEF+MP group than in the LEF group (p < 0.05). Serum albumin levels were higher than the baseline value in both groups (p < 0.05), with no significant between-group difference (p > 0.05). No inter- or intragroup difference in serum creatinine or glycated hemoglobin was observed. During treatment, the relapse rate was lower in the LEF+MP group than in the LEF group (p < 0.05). No irreversible adverse events were observed. In summary, LEF+MP is more effective than LEF monotherapy for DKD combined with MN. Large, long-term, randomized, double-blind, controlled studies are needed to further validate the clinical efficacy of LEF+MP.

Small molecules against the origin and activation of myofibroblast for renal interstitial fibrosis therapy

Renal interstitial fibrosis (RIF) is a common pathological response in a broad range of prevalent chronic kidney diseases and ultimately leads to renal failure and death. Although RIF causes a high morbi-mortality worldwide, effective therapeutic drugs are urgently needed. Myofibroblasts are identified as the main effector during the process of RIF. Multiple types of cells, including fibroblasts, epithelial cells, endothelial cells, macrophages and pericytes, contribute to renal myofibroblasts origin, and lots of mediators, including signaling pathways (Transforming growth factor-β1, mammalian target of rapamycin and reactive oxygen species) and epigenetic modifications (Histone acetylation, microRNA and long non-coding RNA) are participated in renal myofibroblasts activation during renal fibrogenesis, suggesting that these mediators may be the promising targets for treating RIF. In addition, many small molecules show profound therapeutic effects on RIF by suppressing the origin and activation of renal myofibroblasts. Taken together, the review focuses on the mechanisms of the origin and activation of renal myofibroblasts in RIF and the small molecules against them improving RIF, which will provide a new insight for RIF therapy.

Psoriatic Arthritis and Diabetes Mellitus: A Narrative Review

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic immune-mediated inflammatory spondyloarthropathy associated with psoriasis. PsA is frequently associated with metabolic disorders including, obesity, metabolic syndrome, and diabetes mellitus (DM). Type 2 DM is among the most common metabolic disorders, with a prevalence ranging from 2.4 to 14.8% in the general population.

METHODS

We conducted a narrative review of the English-language studies from January 1989 to September 2019 investigating the risk of type 2 DM in patients with PsA, the pathogenic mechanism linking DM to PsA, and the effects on insulin sensitivity exerted by systemic therapies for PsA.

RESULTS

The prevalence of type 2 DM in patients with PsA ranges from 6.1 to 20.2%, generally higher when compared to the general population. The higher risk of DM is reported in women with more severe forms of PsA. Elevated serum levels of adipokines, including TNF-α, which inhibits the autophosphorylation of the insulin receptor and suppresses the expression of glucose transporter 4, favor insulin resistance and could partially explain the association between PsA and DM. Moreover, adiponectin and omentin, with insulin-sensitizing and anti-atherogenic properties, are decreased in patients with PsA. Some of the treatments for PsA could affect the glucose homeostasis. Systemic corticosteroids are known to impair insulin resistance, whereas apremilast (phosphodiesterase type 4 inhibitor) and TNF-α inhibitors could exert neutral effect or reduce the insulin-resistance. The role of IL-17 or IL-23 inhibitors has been marginally investigated.

CONCLUSIONS

Patients affected by PsA have a higher prevalence of type 2 DM compared with the general population. The mechanism linking PsA with DM has not been completely clarified, but some of the principal mediators could be TNF-α and adipokine, especially adiponectin and omentin. Apremilast and TNF-α inhibitor may have a favorable effect and could be safely used in patients with DM.

DIBc nano metal-organic framework improves biochemical and pathological parameters of experimental chronic kidney disease

BACKGROUND

The growing morbidity and mortality rate of chronic kidney disease (CKD) has forced researchers to find more efficient strategies for controlling this disease. Studies have proven the important role of alteration in iron, zinc and selenium metabolism in CKD pathological process. Nanotechnology, through synthetizing nano metal-organic framework (NMOF) structures, can be employed as a valuable strategy for using these trace elements as the key for modification and improvement of CKD-related pathological events. After proving the anti-diabetic property of DIBc NMOF (which contains selenium and zinc) in the previous study, the impact of this NMOF on some important biochemical and pathological parameters of CKD was evaluated in the current study.

METHODS

Knowing that diabetic nephropathy (DN) is the leading cause of CKD, male wistar rats were selected and given a high fat diet for 2 weeks and then were injected with streptozotocin (35 mg/kg) to induce DN. Six weeks after streptozotocin injection, DIBc or metformin treatment started and continued for 8 weeks.

RESULTS

Eight weeks of DIBc treatment decreased plasma fasting blood glucose, blood urea nitrogen, uric acid, malondialdehyde (MDA) and HOMA-IR index compared to DN control and metformin groups. This NMOF significantly reduced urinary albumin excretion rate, MDA and 8-isoprostane, while it increased creatinine clearance in comparison to the above-mentioned groups. Renal histo-pathological images indicated that DIBc ameliorated glomerular basement membrane thickening and wrinkling, mesangial matrix expansion and hypercellularity and presence of intra-cytoplasmic hyaline droplets in proximal cortical tubules of kidney samples.

CONCLUSION

The results showed the therapeutic effect of DIBc on important biochemical and histo-pathological parameters of CKD, so this NMOF could be regarded as a promising novel anti-CKD agent.

Combination of leflunomide and benazepril reduces renal injury of diabetic nephropathy rats and inhibits high-glucose induced cell apoptosis through regulation of NF-κB, TGF-β and TRPC6

Objective: To investigate effects of combination use of leflunomide and benazepril on diabetic nephropathy (DN) both in vivo and in vitro.

Methods: The streptozotocin (STZ) induced Sprague-Dawley rats were treated with leflunomide (15 mg/kg/d), benazepril (15 mg/kg/d) or both the two drugs. Fasting blood glucose (FBG) and renal function indexes including blood urea nitrogen (BUN), serum creatinine (Scr), and proteinuria and kidney/body weight ratio (KW/BW) were measured. HE staining was used for histological analysis. The rat glomerular mesangial cells (RMCs) were treated with high-glucose (150 mg/ml) and the leflunomide and benazepril with both concentrations of 50 μmol/l were used to treat the high-glucose induced cells. TUNEL assay was used for measurement of cell apoptosis. Western blotting was conducted to determine expression of nuclear factor Kappa B (NF-κB), transforming growth factor-β (TGF-β) and transient receptor potential canonical 6 (TRPC6).

Results: The body weight was significantly lower and all indexes of FBG, BUN, Scr, proteinuria and KW/BW ratio, GFR, as well as inflammatory factors TNF-α and IL-6 were significantly increased in the DN group after STZ treatment for 4 weeks. The treatment with leflunomide, benazepril or the both dramatically reduced the above effects induced by STZ, and the alteration was the most significant in the combination group. Treatment of leflunomide and benazepril significantly reduced expression levels of NF-κB, TGF-β and TRPC6 in renal tissues of DN rats as well as in high-glucose induced RMCs. It was also observed leflunomide and benazepril reduced high-glucose induced cell apoptosis of RMCs.

Conclusion: The combination use of leflunomide and benazepril could improve the renal function and reduce the renal injury of DN rats and could reduce the levels of NF-κb, TGF-β and TRPC6 in both DN rats and high-glucose induced RMCs.

The Effects of Administration of Vitamin D, Infliximab, and Leflunomide on Testosterone Concentrations in Rats under Atorvastatin Therapy

Objective

Statins inhibit the 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase enzyme and thus reduce plasma cholesterol levels. Although decreased cholesterol level is the main target of anti-lipidemic drugs, cholesterol has an important role in the synthesis of lipid-based hormones such as testosterone. In this study, the alterations in serum testosterone levels were examined in rats under atorvastatin therapy and their responses to vitamin D, infliximab, and leflunomide supplementation were evaluated.

Materials and Methods

Wistar rats were treated with atorvastatin (100 mg/kg) for 21 days to induce inhibition of the HMG-CoA reductase enzyme activity. Following statin therapy, rats received vitamin D (0.2 μg/kg/day) orally for 15 days, infliximab (7 mg/kg/day) intraperitoneally in two doses, or leflunomide (10 mg/kg/day) orally in two doses. Subsequently, the alterations in serum testosterone levels were measured by ELISA.

Results

Atorvastatin led to a decrease in the testosterone level compared to the vehicle group. Administration of vitamin D, infliximab, and leflunomide under HMG-CoA inhibition insignificantly increased the testosterone level compared to the atorvastatin control group. Furthermore, it appears that rats under statin administration respond better to treatment with leflunomide by achieving a greater induction in testosterone levels than with vitamin D or infliximab.

Conclusion

Our data provide evidence that administration of vitamin D, infliximab, and leflunomide in rats under atorvastatin treatment may ameliorate the serum testosterone levels.

Suppression of aberrant choroidal neovascularization through activation of the aryl hydrocarbon receptor

The aryl hydrocarbon receptor (AhR) is a ligand activated transcription factor, initially discovered for its role in regulating xenobiotic metabolism. There is extensive evidence supporting a multi-faceted role for AhR, modulating physiological pathways important in cell health and disease. Recently we demonstrated that the AhR plays a role in the pathogenesis of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly. We found that loss of AhR exacerbates choroidal neovascular (CNV) lesion formation in a murine model. Herein we tested the therapeutic impact of AhR activation on CNV lesion formation and factors associated with aberrant neovascularization. We screened a panel of synthetic drugs and endogenous AhR ligands, assessed their ability to activate AhR in choroidal endothelial cells, and inhibit angiogenesis in vitro. Drugs with an anti-angiogenic profile were then administered to a murine model of CNV. Two compounds, leflunomide and flutamide, significantly inhibited CNV formation concurrent with positive modifying effects on angiogenesis, inflammation, extracellular matrix remodeling, and fibrosis. These results validate the role of the AhR pathway in regulating CNV pathogenesis, identify mechanisms of AhR-based therapies in the eye, and argue in favor of developing AhR as a drug target for the treatment of neovascular AMD.

Protective effect of L-glutamine against diabetes-induced nephropathy in experimental animal: Role of KIM-1, NGAL, TGF-β1, and collagen-1

Diabetic nephropathy is a serious microvascular complication and one of the main causes of end-stage renal disease. L-Glutamine (LG) is naturally occurring amino acids with antidiabetic and antioxidant potential. The aim of present investigation was to evaluate the potential of LG against streptozotocin (STZ)-induced diabetic nephropathy (DN) in laboratory rats. DN was induced in male Wistar rats (200-220 g) by intraperitoneal administration of STZ (55 mg/kg). Animals were treated orally with either distilled water (10 mg/kg) or LG (250, 500, and 1000 mg/kg) or Sitagliptin (5 mg/kg). Various biochemical, molecular, and histological (hematoxylin-eosin and Masson's trichrome stain) parameters were assessed. Administration of LG (500 and 1000 mg/kg) significantly inhibited (p < .05) STZ-induced alterations in serum and urine biochemistry (urine creatinine, uric acid, albumin, and BUN). It also significantly increased creatinine clearance rate. STZ induced increase in renal oxidonitrosative stress was significantly decreased (p < .05) by LG (500 and 1000 mg/kg) treatment. Upregulated renal KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expression after STZ administration was significantly inhibited (p < .05) by LG (500 and 1000 mg/kg) treatment. Correlation analysis also revealed that antidiabetic potential of LG attenuates STZ-induced elevated renal KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expression. Histopathological alteration induced by STZ in renal tissue was ameliorated by LG treatment. In conclusion, results of present investigation suggest that treatment with LG ameliorated STZ-induced DN via the inhibition of oxidonitrosative stress as well as downregulation of KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expressions.

Association of Chemerin and Vascular Endothelial Growth Factor (VEGF) with Diabetic Nephropathy

Background

Diabetic nephropathy (DN) is a common complication of diabetes, caused by diabetic microvascular lesions. The pathogenesis of DN is complicated, involving genetics, physics, chemistry, and environmental factors. Chemerin is a fat cell factor that participates in regulating inflammation. Vascular endothelial growth factor (VEGF) promotes vascular endothelial cell proliferation, differentiation, and angiogenesis. The relationship role of Chemerin and VEGF in DN is not fully understood.

Material/Methods

SD rats were randomly divided into 2 groups: the control group and the DN group. Streptozotocin was used to construct the DN model. Serum creatinine (Scr), blood urea nitrogen (BUN), and urine microalbumin (UAlb) were detected. Real-time PCR and Western blot were used to test Chemerin and VEGF mRNA and protein expression in kidney tissue. ELISA was performed to test TGF-β1, TNF-α, and INF-γ levels. The correlation of Chemerin and VEGF with renal function and inflammatory factors was analyzed.

Results

DN group rats showed obviously increased Scr and BUN levels, and elevated TGF-β1, TNF-α, and INF-γ secretion (P<0.05). Compared with controls, Chemerin and VEGF were clearly overexpressed in the DN group (P<0.05). Chemerin and VEGF expression were positively correlated with inflammatory factors and renal function.

Conclusions

Chemerin and VEGF play important roles in DN by regulating inflammatory factors and renal function. They may be treated as indicators of DN.