Candesartan Protects Against Cadmium-Induced Hepatorenal Syndrome by Affecting Nrf2, NF-κB, Bax/Bcl-2/Cyt-C, and Ang II/Ang 1-7 Signals

Perindopril Dampens Cd-induced Nephrotoxicity by Suppressing Inflammatory Burden, Ang II/Ang 1-7, and Apoptosis Signaling Pathways

Cadmium (Cd) is one of the most abundant toxic heavy metals, and its exposure is linked to serious kidney intoxication, a major health problem. Evidence reported that inflammatory damage is a key factor in Cd renal intoxication. Perindopril (PER) is an angiotensin-converting enzyme inhibitor approved for treating hypertension and other cardiovascular problems. Significantly, RAS activation results in inflammatory damage. Our study aimed to examine the renoprotective effects of PER in Cd-induced nephrotoxicity, the impact of inflammation, and the underlying molecular mechanisms. PER was given at a dose of 1 mg/kg per day. Cd was injected at a dose of 1.2 mg/kg, as a single dose. Treatment with PER led to a significant decrease in serum levels of urea, creatinine, uric acid, and urine albumin/creatinine ratio. PER effectively mitigated inflammation by decreasing MPO, NO, IL-1β, IL-6, and INF-γ levels mediated by downregulating NF-κB expression and suppressing JAK-1 and STAT3 phosphorylation. PER modulates Ang II/Ang 1-7 axis in Cd-intoxicated rats by decreasing Ang II expression and increasing Ang-(1-7) expression. PER inhibits Cd-induced apoptosis by lowering Bax, cytochrome c, and cleaved caspase 3 expressions while increasing Bcl-2 expression. In conclusion, PER dampens Cd-induced kidney intoxication by modulating Ang II/Ang 1-7 axis, suppressing NF-κB, JAK-1/STAT3, and apoptosis signals.

Nrf2/HO-1 as a therapeutic target in renal fibrosis

Chronic kidney disease (CKD) is one of the most prevalent chronic diseases and affects between 10 and 14 % of the world's population. The World Health Organization estimates that by 2040, the disease will be fifth in prevalence. End-stage CKD is characterized by renal fibrosis, which can eventually lead to kidney failure and death. Renal fibrosis develops due to multiple injuries and involves oxidative stress and inflammation. In the human body, nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in the expression of antioxidant, anti-inflammatory, and cytoprotective genes, which prevents oxidative stress and inflammation damage. Heme oxygenase (HO-1) is an inducible homolog influenced by heme products and after exposure to cellular stress inducers such as oxidants, inflammatory chemokines/cytokines, and tissue damage as an outcome or downstream of Nrf2 activation. HO-1 is known for its antioxidative properties, which play an important role in regulating oxidative stress. In renal diseases-induced tissue fibrosis and xenobiotics-induced renal fibrosis, Nrf2/HO-1 has been targeted with promising results. This review summarizes these studies and highlights the interesting bioactive compounds that may assist in attenuating renal fibrosis mediated by HO-1 activation. In conclusion, Nrf2/HO-1 signal activation could have a renoprotective effect strategy against CKD caused by oxidative stress, inflammation, and consequent renal fibrosis.

Soluble suppression of tumorigenicity 2 is a potential predictor of post-liver transplant renal outcomes

Acute kidney injury is considered an independent prognostic factor for mortality in patients with liver cirrhosis. Non-treated acute kidney injury can progress to hepatorenal syndrome with a poor prognosis. As suppression of tumorigenicity 2 (ST2) is a member of the interleukin-1 receptor family that aggravates inflammation and fibrotic changes in multiple organs, we measured soluble ST2 (sST2) level in the serum and urine of liver-transplant recipients at the time of transplantation. The serum sST2 level significantly increased in liver-transplant recipients with suppressed kidney function compared with that in recipients with normal function. In recipients with severely decreased liver function (model for end-stage liver disease score ≥ 30), the serum sST2 level was higher than that in recipients with preserved liver function (model for end-stage liver disease score ≤ 20, P = 0.028). The serum sST2 level in recipients with hepatorenal syndrome was higher than that in liver-transplant recipients without hepatorenal syndrome (P = 0.003). The serum sST2 level in patients with hepatorenal syndrome was higher than that in recipients without a history of acute kidney injury (P = 0.004). Recipients with hepatorenal syndrome and recovered kidney function showed higher sST2 levels than those who did not recover (P = 0.034). Collectively, an increase in the serum sST2 level reflects a decrease in both kidney and liver functions. Thus, measuring sST2 level at the time of liver transplantation can help predict renal outcomes.

Cadmium cardiotoxicity is associated with oxidative stress and upregulated TLR-4/NF-kB pathway in rats; protective role of agomelatine

Cardiotoxicity is one of the hazardous effects of the exposure to the heavy metal cadmium (Cd). Inflammation and oxidative injury are implicated in the cardiotoxic mechanism of Cd. The melatonin receptor agonist agomelatine (AGM) showed promising effects against oxidative and inflammatory responses. This study evaluated the effect of AGM on Cd-induced cardiotoxicity in rats, pointing to its modulatory effect on TLR-4/NF-kB pathway and HSP70. Rats received AGM for 14 days and a single dose of Cd on day 7 and blood and heart samples were collected for analyses. Cd increased serum CK-MB, AST and LDH and caused cardiac tissue injury. Cardiac malondialdehyde (MDA), nitric oxide (NO) and MPO were elevated and GSH, SOD and GST decreased in Cd-administered rats. AGM ameliorated serum CK-MB, AST and LDH and cardiac MDA, NO and MPO, prevented tissue injury and enhanced antioxidants. AGM downregulated serum CRP and cardiac TLR-4, NF-kB, iNOS, IL-6, TNF-α and COX-2 in Cd-administered rats. HSP70 was upregulated in the heart of Cd-challenged rats treated with AGM. In silico findings revealed the binding affinity of AGM with TLR-4 and NF-kB. In conclusion, AGM protected against Cd cardiotoxicity by preventing myocardial injury and oxidative stress and modulating HSP70 and TLR-4/NF-kB pathway.

Mirtazapine attenuated cadmium-induced neuronal intoxication by regulating Nrf2 and NF-κB/TLR4 signals

Cadmium (Cd) is one of the most hazardous metals to the environment and human health. Neurotoxicity is of the most serious hazards caused by Cd. Mirtazapine (MZP) is a central presynaptic α2 receptor antagonist used effectively in treating several neurological disorders. This study investigated the anti-inflammatory and antioxidant activity of MZP against Cd-induced neurotoxicity. In this study, rats were randomly divided into five groups: control, MZP (30 mg/kg), Cd (6.5 mg/kg/day; i.p), Cd + MZP (15 mg/kg), and Cd + MZP (30 mg/kg). Histopathological examination, oxidative stress biomarkers, inflammatory cytokines, and the impact of Nrf2 and NF-κB/TLR4 signals were assessed in our study. Compared to Cd control rats, MZP attenuated histological abrasions in the cerebral cortex and CA1 and CA3 regions of the hippocampus as well as the dentate gyrus. MZP attenuated oxidative injury by upregulating Nrf2. In addition, MZP suppressed the inflammatory response by decreasing TNF-α, IL-1β, and IL-6 mediated by downregulating TLR4 and NF-κB. It is noteworthy that MZP's neuroprotective actions were dose-dependent. Collectively, MZP is a promising therapeutic strategy for attenuating Cd-induced neurotoxicity by regulating Nrf2, and NF-κB/TLR4 signals, pending further study in clinical settings.

Alleviative effects of pinostrobin against cadmium-induced renal toxicity in rats by reducing oxidative stress, apoptosis, inflammation, and mitochondrial dysfunction

Introduction

Cadmium (Cd) is a highly toxic heavy metal that can be found everywhere in the environment and can have harmful effects on both human and animal health. Pinostrobin (PSB) is a bioactive natural flavonoid isolated from Boesenbergia rotunda with several pharmacological properties, such as antiinflammatory, anticancer, antioxidant, and antiviral. This investigation was intended to assess the therapeutic potential of PSB against Cd-induced kidney damage in rats.

Methods

In total, 48 Sprague Dawley rats were divided into four groups: a control, a Cd (5 mg/kg), a Cd + PSB group (5 mg/kg Cd and 10 mg/kg PSB), and a PSB group (10 mg/kg) that received supplementation for 30 days.

Results

Exposure to Cd led to a decrease in the activities of catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX), whereas levels of reactive oxygen species (ROS) and malondialdehyde (MDA) increased. Cd exposure also caused a substantial increase in urea, kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and creatinine levels. Moreover, a noticeable decline was noticed in creatinine clearance. Moreover, Cd exposure considerably increased the levels of inflammatory indices, including interleukin-1b (IL-1b), tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), nuclear factor kappa-B (NF-kB), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) activity. Cd treatment decreased the expression of the antiapoptotic markers (Bcl-2) while increasing the expression of apoptotic markers (Bax and Caspase-3). Furthermore, Cd treatment substantially reduced the TCA cycle enzyme activity, such as alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and isocitrate dehydrogenase. Moreover, mitochondrial electron transport chain enzymes, succinatedehydrogenase, NADH dehydrogenase, cytochrome c-oxidase, and coenzyme Q-cytochrome reductase activities were also decreased following Cd exposure. PSB administration substantially reduced the mitochondrial membrane potential while inducing significant histological damage. However, PSB treatment significantly reduced Cd-mediated renal damage in rats.

Conclusion

Thus, the present investigation discovered that PSB has ameliorative potential against Cd-induced renal dysfunction in rats.

Clinical Research Progress of Small Molecule Compounds Targeting Nrf2 for Treating Inflammation-Related Diseases

Studies have found that inflammation is a symptom of various diseases, such as coronavirus disease 2019 (COVID-19) and rheumatoid arthritis (RA); it is also the source of other diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), lupus erythematosus (LE), and liver damage. Nrf2 (nuclear factor erythroid 2-related factor 2) is an important multifunctional transcription factor in cells and plays a central regulatory role in cellular defense mechanisms. In recent years, several studies have found a strong association between the activation of Nrf2 and the fight against inflammation-related diseases. A number of small molecule compounds targeting Nrf2 have entered clinical research. This article reviews the research status of small molecule compounds that are in clinical trials for the treatment of COVID-19, rheumatoid arthritis, Alzheimer’s disease, Parkinson’s disease, lupus erythematosus, and liver injury.