Diabetes aggravates renal ischemia and reperfusion injury in rats by exacerbating oxidative stress, inflammation, and apoptosis

Alpha-cyperone mitigates renal ischemic injury via modulation of HDAC-2 expression in diabetes: Insights from molecular dynamics simulations and experimental evaluation

Chronic diabetes mellitus is reported to be associated with acute kidney injury. The enzyme histone deacetylase-2 (HDAC-2) was found to be upregulated in diabetes-related kidney damage. Alpha-cyperone (α-CYP) is one of the active ingredients of Cyperus rotundus that possesses antioxidant and anti-inflammatory effects. We evaluated the effect of α-CYP on improving oxidative stress and tissue inflammation following renal ischemia/reperfusion (I/R) injury in diabetic rats. The effect of α-CYP on HDAC-2 expression in renal homogenates and in the NRK-52 E cell line was evaluated following renal I/R injury and high glucose conditions, respectively. Molecular docking was used to investigate the binding of α-CYP with the HDAC-2 active site. Both renal function and oxidative stress were shown to be impaired in diabetic rats due to renal I/R injury. Significant improvements in kidney/body weight ratio, creatinine clearance, serum creatinine, blood urea nitrogen (BUN), and uric acid were observed in diabetic rats treated with α-CYP (50 mg/kg) two weeks prior to renal I/R injury. α-CYP treatment also improved histological alterations in renal tissue and lowered levels of malondialdehyde, myeloperoxidase, and hydroxyproline. Treatment with α-CYP suppressed the increased HDAC-2 expression in the renal tissue of diabetic rats and in the NRK-52 E cell line. The molecular docking reveals that α-CYP binds to HDAC-2 with good affinity, ascertained by molecular dynamics simulations and binding free energy analysis. Overall, our data suggest that α-CYP can effectively prevent renal injury in diabetic rats by regulating oxidative stress, tissue inflammation, fibrosis and inhibiting HDAC-2 activity.

Low rate of severe-end-stage kidney disease after SABR for localised primary kidney cancer

BACKGROUND

Stereotactic ablative body radiotherapy (SABR) is an emerging treatment for patients with primary renal cell carcinoma (RCC). However, its impact on renal function is unclear. This study aimed to evaluate incidence and clinical factors predictive of severe to end-stage chronic kidney disease (CKD) after SABR for RCC.

METHODS AND MATERIALS

This was a Single institutional retrospective analysis of patients with diagnosed primary RCC receiving SABR between 2012-2020. Adult patients with no metastatic disease, baseline estimated glomerular filtration rate (eGFR) of ≥ 30 ml/min/1.73 m2, and at least one post-SABR eGFR at six months or later were included in this analysis. Patients with upper tract urothelial carcinoma were excluded. Primary outcome was freedom from severe to end-stage CKD, determined using the Kaplan-Meier estimator. The impact of baseline CKD, age, hypertension, diabetes, tumor size and fractionation schedule were assessed by Cox proportional hazard models.

RESULTS

Seventy-eight consecutive patients were included, with median age of 77.8 years (IQR 70-83), tumor size of 4.5 cm (IQR 3.9-5.8) and follow-up of 42.2 months (IQR 23-60). Baseline median eGFR was 58 mls/min; 55% (n = 43) of patients had baseline CKD stage 3 and the remainder stage 1-2. By last follow-up, 1/35 (2.8%) of baseline CKD 1-2, 7/27 (25.9%) CKD 3a and 11/16 (68.8%) CKD 3b had developed CKD stage 4-5. The estimated probability of freedom from CKD stage 4-5 at 1 and 5 years was 89.6% (CI 83.0-97.6) and 65% (CI 51.4-81.7) respectively. On univariable analysis, worse baseline CKD (p < 0.0001) and multi-fraction SABR (p = 0.005) were predictive for development of stage 4-5 CKD though only the former remained significant in multivariable model.

CONCLUSION

In this elderly cohort with pre-existing renal dysfunction, SABR achieved satisfactory nephron sparing with acceptable rates of severe to end-stage CKD. It can be an attractive option in patients who are medically inoperable.

Berberine Metabolites Stimulate GLP-1 Secretion by Alleviating Oxidative Stress and Mitochondrial Dysfunction

Berberine (BBR) is a principal component of Rhizoma coptidis known for its therapeutic potential in treating diseases such as type 2 diabetes mellitus (T2DM) and obesity. Despite the trace levels of BBR in plasma, it's believed that its metabolites play a pivotal role in its biological activities. While BBR is recognized to promote GLP-1 production in intestinal L cells, the cytoprotective effects of its metabolites on these cells are yet to be explored. The present study investigates the effects of BBR metabolites on GLP-1 secretion and the underlying mechanisms. Our results revealed that, out of six BBR metabolites, berberrubine (BBB) and palmatine (PMT) significantly increased the production and glucose-stimulated secretion of GLP-1 in GLUTag cells. Notably, both BBB and PMT could facilitate GLP-1 and insulin secretion and enhance glucose tolerance in standard mice. Moreover, a single dose of PMT could markedly increase plasma GLP-1 and improve glucose tolerance in mice with obesity induced by a high-fat diet. In palmitic acid or TNF[Formula: see text]-treated GLUTag cells, BBB and PMT alleviated cell death, oxidative stress, and mitochondrial dysfunction. Furthermore, they could effectively reverse inflammation-induced inhibition of the Akt signaling pathway. In general, these insights suggest that the beneficial effects of orally administered BBR on GLP-1 secretion are largely attributed to the pharmacological activity of BBB and PMT by their above cytoprotective effects on L cells, which provide important ideas for stimulating GLP-1 secretion and the treatment of T2DM.

Renoprotective effect of esculetin against ischemic acute kidney injury-diabetic comorbidity

Mitophagy maintains cellular homeostasis by eliminating damaged mitochondria. Accumulated damaged mitochondria can lead to oxidative stress and cell death. Induction of the PINK1/Parkin-mediated mitophagy is reported to be renoprotective in acute kidney injury (AKI). Esculetin, a naturally available coumarin, has shown protective action against diabetic complications. However, its effect on AKI-diabetes comorbidity has not been explored yet. Therefore, we aimed to investigate the renoprotective effect of esculetin against AKI under diabetic conditions via regulating PINK1/Parkin-mediated mitophagy. For this, type 1 diabetic male Wistar rats were treated with two doses of esculetin (50 and 100 mg/kg/day orally) for five days followed by AKI induction by bilateral ischemic-reperfusion injury (IRI). NRK-52E cells grown in high glucose were exposed to sodium azide (10 mM) for induction of hypoxia/reperfusion injury (HRI) in-vitro. Esculetin (50 µM) treatment for 24 h was given to the cells before HRI. The in-vitro samples were utilized for cell viability and ΔΨm assay, immunoblotting, and immunofluorescence. Rats' plasma, urine, and kidney samples were collected for biochemical analysis, histopathology, and western blotting. Our results showed a significant decrease in kidney injury-specific markers and increased expression of mitophagy markers (PINK1 and Parkin) with esculetin treatment. Moreover, esculetin prevented the HRI and hyperglycemia-induced decrease in ΔΨm and autophagosome marker. Also, esculetin therapy reduced oxidative stress via increased Nrf2 and Keap1 expression. Esculetin attenuated AKI under diabetic condition by preventing mitochondrial dysfunction via inducing PINK1/Parkin-mediated mitophagy, suggesting its potential as an effective therapy for preventing AKI-diabetes comorbidity.

Perioperative Glycemic Management in Cardiac Surgery: A Narrative Review

Diabetes and hyperglycemic events in cardiac surgical patients are associated with postoperative morbidity and mortality. The causes of dysglycemia, the abnormal fluctuations in blood glucose concentrations, in the perioperative period include surgical stress, surgical techniques, medications administered perioperatively, and patient factors. Both hyperglycemia and hypoglycemia lead to poor outcomes after cardiac surgery. While trying to control blood glucose concentration tightly for better postoperative outcomes, hypoglycemia is the main adverse event. Currently, there is no definite consensus on the optimum perioperative blood glucose concentration to be maintained in cardiac surgical patients. This review provides an overview of perioperative glucose homeostasis, the pathophysiology of dysglycemia, factors that affect glycemic control in cardiac surgery, and current practices for glycemic control in cardiac surgery.

Tert-butylhydroquinone attenuates LPS-induced pyroptosis of IPEC-J2 cells via downregulating HMGB1/TLR4/NF-κB axis

Inflammatory response induced by biological stress usually occurs in weaning piglets, it reduces the production performance of piglets and even causes death. Tert-butylhydroquinone (TBHQ) is a food additive that has the effect of anti-inflammation and anti-oxidation. However, there are few reports related to the protective mechanisms of TBHQ on lipopolysaccharide (LPS) induced injury in intestinal porcine epithelial (IPEC-J2) cells. Quantitative real-time polymerase chain reaction and western blot analysis, respectively, detected the mRNA levels and protein expressions related to pyroptosis, tight junction (TJ) protein and high-mobility group box 1/toll-like receptor 4/nuclear factor kappa-B (HMGB1/TLR4/NF-κB) axis. Localisation and expression of NOD-like receptor pyrin domain containing 3 (NLRP3), HMGB1 and P-NF-κB proteins detected by immunofluorescence. The results showed that TBHQ (12.5 and 25 μM) can increase cell activity and reduce intracellular lactate dehydrogenase (LDH) levels in a dose-dependent manner. LPS significantly decreases cell viability and increases the LDH level. However, pretreatment with TBHQ evidently increases cell viability and decreases the LDH level of IPEC-J2 cells. In addition, treatment with LPS decreased the mRNA level and protein expression of zonula occludens-1, occludin and claudin-1, and increased the mRNA level and protein expression of pyroptosis and HMGB1/TLR4/NF-κB axis. Interestingly, pretreatment with TBHQ increased the TJ protein expressions as well as decreased the mRNA level and protein expressions of pyroptosis and HMGB1/TLR4/NF-κB axis. Moreover, the results of immunofluorescence showed that TBHQ significantly reduced the expression of NLRP3, HMGB1 and P-NF-κB in LPS-induced injury of IPEC-J2 cells. Therefore, we come to the conclusion that TBHQ attenuates LPS-induced pyroptosis in IPEC-J2 cells through downregulation of the HMGB1/TLR4/NF-κB axis, TBHQ may become a potential feed additive for preventing inflammatory diarrhoea in piglets.

SGLT2 inhibitors, intrarenal hypoxia and the diabetic kidney: insights into pathophysiological concepts and current evidence

Approximately 20-40% of all diabetic patients experience chronic kidney disease, which is related to higher mortality (cardiovascular and all-cause). A large body of evidence suggests that renal hypoxia is one of the main forces that drives diabetic kidney disease, both in its early and advanced stages. It promotes inflammation, generation of intrarenal collagen, capillary rarefaction and eventually accumulation of extracellular matrix that destroys normal renal architecture. SGLT2 inhibitors are unquestionably a practice-changing drug class and a valuable weapon for patients with type 2 diabetes and chronic kidney disease. They have achieved several beneficial kidney effects after targeting multiple and interrelated signaling pathways, including renal hypoxia, independent of their antihyperglycemic activities. This manuscript discusses the pathophysiological concepts that underly their possible effects on modulating renal hypoxia. It also comprehensively investigates both preclinical and clinical studies that explored the possible role of SGLT2 inhibitors in this setting, so as to achieve long-term renoprotective benefits.

In Vivo and In Silico Studies of the Hepatoprotective Activity of Tert-Butylhydroquinone

Tert-butylhydroquinone (TBHQ) is a synthetic food antioxidant with biological activities, but little is known about its pharmacological benefits in liver disease. Therefore, this work aimed to evaluate TBHQ during acute liver damage induced by CCl4 (24 h) or BDL (48 h) in Wistar rats. It was found that pretreatment with TBHQ prevents 50% of mortality induced by a lethal dose of CCl4 (4 g/kg, i.p.), and 80% of BDL+TBHQ rats survived, while only 50% of the BDL group survived. Serum markers of liver damage and macroscopic and microscopic (H&E staining) observations suggest that TBHQ protects from both hepatocellular necrosis caused by the sublethal dose of CCl4 (1.6 g/kg, i.p.), as well as necrosis/ductal proliferation caused by BDL. Additionally, online databases identified 49 potential protein targets for TBHQ. Finally, a biological target candidate (Keap1) was evaluated in a proof-of-concept in silico molecular docking assay, resulting in an interaction energy of -5.5491 kcal/mol, which was higher than RA839 and lower than monoethyl fumarate (compounds known to bind to Keap1). These findings suggest that TBHQ increases the survival of animals subjected to CCl4 intoxication or BDL, presumably by reducing hepatocellular damage, probably due to the interaction of TBHQ with Keap1.

Metformin alleviates sodium arsenite-induced hepatotoxicity and glucose intolerance in mice by suppressing oxidative stress, inflammation, and apoptosis

BACKGROUND

Epidemiological studies have shown that exposure to sodium arsenite (NaAsO2) causes diabetes and hepatotoxicity. Metformin (MET), an oral hypoglycemic agent, has long been used in diabetes therapy. In addition, MET has been shown to have hepatoprotective effects. In this study, we investigated the effects of MET on NaAsO2-induced hepatotoxicity and glucose intolerance in mice.

METHODS

Mice were divided into four groups: Groups I and II received distilled water and NaAsO2 (10 mg/kg, p.o.) for five weeks, respectively. Groups III and IV were treated with NaAsO2 (10 mg/kg, p.o.) for three weeks, followed by MET (125 and 250 mg/kg, p.o.) for the last two weeks before NaAsO2. A glucose tolerance test was performed on day 35. The serum and tissue parameters were also evaluated.

RESULTS

Histopathological examination revealed NaAsO2-induced liver and pancreatic damage. NaAsO2 caused hyperglycemia, glucose intolerance, and a significant increase in liver function enzymes. Administration of NaAsO2 significantly reduced hepatic superoxide dismutase, catalase, glutathione peroxidase, and total thiol levels and increased the content of reactive thiobarbituric acid substances. In addition, it led to an increase in liver nitric oxide levels and protein expression of tumor necrosis factor-α, nuclear factor kappa B, and cysteine-aspartic proteases-3. In contrast, treatment with MET (250 mg/kg) significantly improved NaAsO2-induced biochemical and histopathological changes.

CONCLUSION

Our findings suggest that the significant effects of MET against NaAsO2-induced hepatotoxicity and glucose intolerance may be exerted via the regulation of oxidative stress, followed by suppression of inflammation and apoptosis.

BM-MSCs alleviate diabetic nephropathy in male rats by regulating ER stress, oxidative stress, inflammation, and apoptotic pathways

Introduction: Diabetic nephropathy (DN), a chronic kidney disease, is a major cause of end-stage kidney disease worldwide. Mesenchymal stem cells (MSCs) have become a promising option to mitigate several diabetic complications. Methods: In this study, we evaluated the therapeutic potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) in a rat model of STZ-induced DN. After the confirmation of diabetes, rats were treated with BM-MSCs and sacrificed at week 12 after treatment. Results: Our results showed that STZ-induced DN rats had extensive histopathological changes, significant upregulation in mRNA expression of renal apoptotic markers, ER stress markers, inflammatory markers, fibronectin, and intermediate filament proteins, and reduction of positive immunostaining of PCNA and elevated P53 in kidney tissue compared to the control group. BM-MSC therapy significantly improved renal histopathological changes, reduced renal apoptosis, ER stress, inflammation, and intermediate filament proteins, as well as increased positive immunostaining of PCNA and reduced P53 in renal tissue compared to the STZ-induced DN group. Conclusion: In conclusion, our study indicates that BM-MSCs may have therapeutic potential for the treatment of DN and provide important insights into their potential use as a novel therapeutic approach for DN.

A Review of the Potential of Nuclear Factor [Erythroid-Derived 2]-like 2 Activation in Autoimmune Diseases

An autoimmune disease is the consequence of the immune system attacking healthy cells, tissues, and organs by mistake instead of protecting them. Inflammation and oxidative stress (OS) are well-recognized processes occurring in association with acute or chronic impairment of cell homeostasis. The transcription factor Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is of major importance as the defense instrument against OS and alters anti-inflammatory activities related to different pathological states. Researchers have described Nrf2 as a significant regulator of innate immunity. Growing indications suggest that the Nrf2 signaling pathway is deregulated in numerous diseases, including autoimmune disorders. The advantageous outcome of the pharmacological activation of Nrf2 is an essential part of Nrf2-based chemoprevention and intervention in other chronic illnesses, such as neurodegeneration, cardiovascular disease, autoimmune diseases, and chronic kidney and liver disease. Nevertheless, a growing number of investigations have indicated that Nrf2 is already elevated in specific cancer and disease steps, suggesting that the pharmacological agents developed to mitigate the potentially destructive or transformative results associated with the protracted activation of Nrf2 should also be evaluated. The activators of Nrf2 have revealed an improvement in the progress of OS-associated diseases, resulting in immunoregulatory and anti-inflammatory activities; by contrast, the depletion of Nrf2 worsens disease progression. These data strengthen the growing attention to the biological properties of Nrf2 and its possible healing power on diseases. The evidence supporting a correlation between Nrf2 signaling and the most common autoimmune diseases is reviewed here. We focus on the aspects related to the possible effect of Nrf2 activation in ameliorating pathologic conditions based on the role of this regulator of antioxidant genes in the control of inflammation and OS, which are processes related to the progression of autoimmune diseases. Finally, the possibility of Nrf2 activation as a new drug development strategy to target pathogenesis is proposed.

Common mechanisms underlying diabetic vascular complications: focus on the interaction of metabolic disorders, immuno-inflammation, and endothelial dysfunction

Diabetic vascular complications (DVCs), including macro- and micro- angiopathy, account for a high percentage of mortality in patients with diabetes mellitus (DM). Endothelial dysfunction is the initial and role step for the pathogenesis of DVCs. Hyperglycemia and lipid metabolism disorders contribute to endothelial dysfunction via direct injury of metabolism products, crosstalk between immunity and inflammation, as well as related interaction network. Although physiological and phenotypic differences support their specified changes in different targeted organs, there are still several common mechanisms underlying DVCs. Also, inhibitors of these common mechanisms may decrease the incidence of DVCs effectively. Thus, this review may provide new insights into the possible measures for the secondary prevention of DM. And we discussed the current limitations of those present preventive measures in DVCs research. Video Abstract.

A bibliometric analysis of publications in Renal Failure in the last three decades

Publications in Renal Failure in Science Citation Index Expanded (SCI-EXPANDED) between 1992 and 2021 were analyzed. Six publication indicators: total, independent, collaborative, first author, corresponding author, and single author publications as well as their related citation indicators, were used to compare performances of countries, institutes, and authors. Comparison of the highly cited papers and journal's impact factor (IF) contributors was discussed. In addition, the main research topics in the journal were presented. Results show that China published the most total articles and reviews, as well as the first-author papers and corresponding-author papers in the journal. The Chang Gung Memorial Hospital in Taiwan ranked the top in five publication indicators: total, single-institution, inter-institutionally collaborative, first author, and corresponding-author papers. A low percentage of productive authors emerged as a journal IF contributor. Similarly, only a limited relationship between highly cited papers and IF contributing papers was found. Publications related to hemodialysis, chronic kidney disease, and acute kidney injury were the most popular topic, while meta-analysis was new focus in the last decade in the journal.

Neuroprotective Effects of Phenolic Antioxidant Tert-butylhydroquinone (tBHQ) in Brain Diseases

Human life and health are gravely threatened by brain diseases. The onset and progression of the illnesses are influenced by a variety of factors, including pathogenic causes, environmental factors, mental issues, etc. According to scientific studies, neuroinflammation and oxidative stress play a significant role in the development and incidence of brain diseases by producing pro-inflammatory cytokines and oxidative tissue damage to induce inflammation and apoptosis. Neuroinflammation, oxidative stress, and oxidative stress-related changes are inseparable factors in the etiology of several brain diseases. Numerous neurodegenerative diseases have undergone substantial research into the therapeutic alternatives that target oxidative stress, the function of oxidative stress, and the possible therapeutic use of antioxidants. Formerly, tBHQ is a synthetic phenolic antioxidant, which has been widely used as a food additive. According to recent researches, tBHQ can suppress the processes that lead to neuroinflammation and oxidative stress, which offers a fresh approach to treating brain diseases. In order to achieve the goal of decreasing inflammation and apoptosis, tBHQ is a specialized nuclear factor erythroid 2-related factor (Nrf2) activator that decreases oxidative stress and enhances antioxidant status by upregulating the Nrf2 gene and reducing nuclear factor kappa-B (NF-κB) activity. This article reviews the effects of tBHQ on neuroinflammation and oxidative stress in recent years and looks into how tBHQ inhibits neuroinflammation and oxidative stress through human, animal, and cell experiments to play a neuroprotective role in Alzheimer's disease (AD), stroke, depression, and Parkinson's disease (PD). It is anticipated that this article will be useful as a reference for upcoming research and the creation of drugs to treat brain diseases.

Both hyperglycemia and hyperuricemia aggravate acute kidney injury during cholesterol embolism syndrome despite opposite effects on kidney infarct size

Kidney cholesterol crystal embolism (CCE) occurs in advanced atherosclerosis and induces a thrombotic (micro)angiopathy, a drop in the glomerular filtration rate (GFR), and an ischemic kidney infarction with necroinflammation. We speculated that common metabolic comorbidities such as diabetes or hyperuricemia would independently modulate each of these distinct pathophysiological processes. To test this, experimental CCE was induced by injecting cholesterol crystals into the left kidney artery of mice and thrombotic angiopathy, GFR drop, and infarct size were analyzed after 24 hours in the presence of hyperglycemia (about 500 mg/dL) or hyperuricemia (about 8 mg/dL) or their absence. In healthy mice, unilateral CCE caused diffuse thrombotic angiopathy in interlobar, arcuate and interlobular arteries, followed by a 50% or less drop in GFR compared to baseline and a variable degree of ischemic kidney necrosis. Hyperglycemia but not hyperuricemia aggravated thrombotic angiopathy although both caused a GFR decline, albeit via different mechanisms. Hyperglycemia aggravated GFR loss by increasing necroinflammation and infarct size, while the antioxidative effects of hyperuricemia reasonably attenuated necroinflammation and infarct size but induced a diffuse vasoconstriction in affected and unaffected kidney tissue. Thus, both hyperglycemia or hyperuricemia aggravate CCE-induced acute kidney failure despite having opposite effects on ischemic necroinflammation and infarction.

Insights into the Molecular Mechanisms of NRF2 in Kidney Injury and Diseases

Redox is a constant phenomenon in organisms. From the signaling pathway transduction to the oxidative stress during the inflammation and disease process, all are related to reduction-oxidation (redox). Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor targeting many antioxidant genes. In non-stressed conditions, NRF2 maintains the hemostasis of redox with housekeeping work. It expresses constitutively with basal activity, maintained by Kelch-like-ECH-associated protein 1 (KEAP1)-associated ubiquitination and degradation. When encountering stress, it can be up-regulated by several mechanisms to exert its anti-oxidative ability in diseases or inflammatory processes to protect tissues and organs from further damage. From acute kidney injury to chronic kidney diseases, such as diabetic nephropathy or glomerular disease, many results of studies have suggested that, as a master of regulating redox, NRF2 is a therapeutic option. It was not until the early termination of the clinical phase 3 trial of diabetic nephropathy due to heart failure as an unexpected side effect that we renewed our understanding of NRF2. NRF2 is not just a simple antioxidant capacity but has pleiotropic activities, harmful or helpful, depending on the conditions and backgrounds.

Exosomes for angiogenesis induction in ischemic disorders

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to "cure" ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100-150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.

Abietic acid ameliorates nephropathy progression via mitigating renal oxidative stress, inflammation, fibrosis and apoptosis in high fat diet and low dose streptozotocin-induced diabetic rats

BACKGROUND

Abietic acid (AA) has been reported to exhibit anti-inflammatory activity, however its protective effect against inflammation and its trigger factor i.e., oxidative stress and the related sequelae i.e., apoptosis and fibrosis in the kidney in diabetes mellitus (DM) is unknown.

PURPOSE

To identify the ability of AA to mitigate the inflammatory and inflammation-related insults to the kidney in DM.

METHODS & STUDY DESIGN

Adult male rats were induced type-2 DM by feeding with a high-fat diet for twelve weeks followed by injection with a single dose of streptozotocin (STZ) (30 mg/kg/bw) intraperitoneally at twelve weeks. Following DM confirmation, AA (10 and 20 mg/kg/day) was given orally for another four weeks. Then the fasting blood glucose (FBG) and renal profile were determined and oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) tests were performed. A day after the last treatment, rats were sacrificed and kidneys were harvested and subjected for histopathological and molecular biological analysis.

RESULTS

AA treatment was found to reduce the FBG, serum urea and creatinine levels (p < 0.05) while improving the OGTT and ITT (p < 0.05) in diabetic rats. Besides, AA treatment also mitigated kidney histopathological changes, reduces kidney oxidative stress as reflected by reduced levels of RAGE and Keap1 but increased levels of kidney antioxidants Nrf2, SOD, CAT, GPX, HO-1 & NQO-1 (p < 0.05). Additionally, AA treatment also decreases kidney inflammation (NF-kB p65, IL-1β, IL-6, TNF-α and iNOS) and fibrosis (TGF-β1 and GSK-3β) (p < 0/05). Kidney apoptosis decreased as reflected by decreased levels of Bax, caspase-3 and caspase-9 while its anti-apoptosis Bcl-2 protein levels increased (p < 0.05).

CONCLUSION

AA helps to mitigate nephropathy development in DM via counteracting oxidative stress, inflammation and apoptosis.

Polyethylene glycol capped gold nanoparticles ameliorate renal ischemia-reperfusion injury in diabetic mice through AMPK-Nrf2 signaling pathway

The aim of this study is to investigate the protective effect of polyethylene glycol capped gold nanoparticles (PEG-AuNPs) on renal ischemia-reperfusion injury (I/R)-induced acute kidney injury (AKI) in diabetic mice via the activation of adenosine 5' monophosphate-activated protein kinase-nuclear factor erythroid-2-related factor-2 (AMPK-Nrf2) pathway. Diabetes was induced in male mice (12/group) by streptozotocin (50 mg/kg) for 5 consecutive days. After 4 weeks, the mice have intravenously received doses of PEG-AuNPs (40, 150, and 400 µg/kg body weight) for 3 consecutive days, and then animals were subjected to 30 min ischemia and 48 h reperfusion. Following the treatment with three different doses of PEG-AuNPs, the levels of blood urea nitrogen (BUN) and creatinine were reduced. Obvious reduction in renal tubular atrophy, glomerular damage, mitochondrial damage, and necrotic area were ultra-structurally detected, and renal interstitial inflammation and apoptosis were diminished. Moreover, PEG-AuNPs increased the recovering of damaged renal cells, suppressed significantly levels of malondialdehyde (MDA), downregulated significantly the level of inflammatory cytokines (TNF-α and IL-1β), and upregulated the AMPK-Nrf2 pathway. PEG-AuNPs exhibited a promising alternative therapeutic target for diabetic renal I/R-induced AKI through upregulation of AMPK/PI3K/AKT path which additionally stimulated Nrf2-regulated antioxidant enzymes in a dose-dependent manner.

Single and combined effect of bisphenol A with high sucrose diet on the diabetic and renal tubular dysfunction phenotypes in Drosophila melanogaster

In the present study, effect of exposure of bisphenol A (BPA) and combined exposure of BPA + HSD has been investigated on the glucose homeostasis and associated renal complications in Drosophila. Exposure of 1.0 mM BPA alone induced type 2 diabetes like condition (T2D) in adult male D. melanogaster via oxidative stress. Elevated TGF-β signaling was evident by increased expression of baboon (babo) in BPA exposed organism that stimulated the modulation of extracellular matrix (ECM) component collagen IV resulting in the fibrosis of the Malpighian tubules (MTs). Combined exposure of BPA + HSD (high sucrose diet) resulted in the increased magnitude of T2D and MTs dysfunction parameters. Taken together, the study illustrates that BPA has diabetogenic potential in exposed Drosophila that caused adverse effects on their MTs and combined exposure with BPA and HSD could aggravate the renal tubular dysfunction. The study further suggests the use of Drosophila model to study the environmental chemicals induced diabetes mediated renal dysfunction.

Oxidative Stress and NRF2/KEAP1/ARE Pathway in Diabetic Kidney Disease (DKD): New Perspectives

Diabetes mellitus (DM) is one of the most debilitating chronic diseases worldwide, with increased prevalence and incidence. In addition to its macrovascular damage, through its microvascular complications, such as Diabetic Kidney Disease (DKD), DM further compounds the quality of life of these patients. Considering DKD is the main cause of end-stage renal disease (ESRD) in developed countries, extensive research is currently investigating the matrix of DKD pathophysiology. Hyperglycemia, inflammation and oxidative stress (OS) are the main mechanisms behind this disease. By generating pro-inflammatory factors (e.g., IL-1,6,18, TNF-α, TGF-β, NF-κB, MCP-1, VCAM-1, ICAM-1) and the activation of diverse pathways (e.g., PKC, ROCK, AGE/RAGE, JAK-STAT), they promote a pro-oxidant state with impairment of the antioxidant system (NRF2/KEAP1/ARE pathway) and, finally, alterations in the renal filtration unit. Hitherto, a wide spectrum of pre-clinical and clinical studies shows the beneficial use of NRF2-inducing strategies, such as NRF2 activators (e.g., Bardoxolone methyl, Curcumin, Sulforaphane and their analogues), and other natural compounds with antioxidant properties in DKD treatment. However, limitations regarding the lack of larger clinical trials, solubility or delivery hamper their implementation for clinical use. Therefore, in this review, we will discuss DKD mechanisms, especially oxidative stress (OS) and NRF2/KEAP1/ARE involvement, while highlighting the potential of therapeutic approaches that target DKD via OS.

Targeting NRF2 in Type 2 diabetes mellitus and depression: Efficacy of natural and synthetic compounds

Evidence supports a strong bidirectional association between depression and Type 2 diabetes mellitus (T2DM). The harmful impact of oxidative stress and chronic inflammation on the development of both disorders is widely accepted. Nuclear factor erythroid 2-related factor 2 (NRF2) is a pertinent target in disease management owing to its reputation as the master regulator of antioxidant responses. NRF2 influences the expression of various cytoprotective phase 2 antioxidant genes, which is hampered in both depression and T2DM. Through interaction and crosstalk with several signaling pathways, NRF2 endeavors to contain the widespread oxidative damage and persistent inflammation involved in the pathophysiology of depression and T2DM. NRF2 promotes the neuroprotective and insulin-sensitizing properties of its upstream and downstream targets, thereby interrupting and preventing disease advancement. Standard antidepressant and antidiabetic drugs may be powerful against these disorders, but unfortunately, they come bearing distressing side effects. Therefore, exploiting the therapeutic potential of NRF2 activators presents an exciting opportunity to manage such bidirectional and comorbid conditions.

Dissecting the Crosstalk Between Nrf2 and NF-κB Response Pathways in Drug-Induced Toxicity

Nrf2 and NF-κB are important regulators of the response to oxidative stress and inflammation in the body. Previous pharmacological and genetic studies have confirmed crosstalk between the two. The deficiency of Nrf2 elevates the expression of NF-κB, leading to increased production of inflammatory factors, while NF-κB can affect the expression of downstream target genes by regulating the transcription and activity of Nrf2. At the same time, many therapeutic drug-induced organ toxicities, including hepatotoxicity, nephrotoxicity, cardiotoxicity, pulmonary toxicity, dermal toxicity, and neurotoxicity, have received increasing attention from researchers in clinical practice. Drug-induced organ injury can destroy body function, reduce the patients’ quality of life, and even threaten the lives of patients. Therefore, it is urgent to find protective drugs to ameliorate drug-induced injury. There is substantial evidence that protective medications can alleviate drug-induced organ toxicity by modulating both Nrf2 and NF-κB signaling pathways. Thus, it has become increasingly important to explore the crosstalk mechanism between Nrf2 and NF-κB in drug-induced toxicity. In this review, we summarize the potential molecular mechanisms of Nrf2 and NF-κB pathways and the important effects on adverse effects including toxic reactions and look forward to finding protective drugs that can target the crosstalk between the two.

Risk factors of acute kidney injury in patients with Stanford type B aortic dissection involving the renal artery who underwent thoracic endovascular aortic repair

Background

Acute kidney injury (AKI) is one of the most common and serious complications in patients with type B aortic dissection (TBAD). This study aimed at investigating the incidence and risk factors of in-hospital AKI in TBAD patients involving the renal artery who underwent thoracic endovascular aortic repair (TEVAR) only.

Methods

A total of 256 patients who were diagnosed as TBAD combined with renal artery involvement were included in this retrospective study. All patients were divided into the AKI group and the non-AKI group according to the KDIGO criteria. The risk factors for AKI were identified using a multivariate logistic regression model.

Results

A total of 256 patients were included in this study, and the incidence of AKI was 18% (46/256). Patients in the AKI group were more likely to have a higher proportion of the youth, a higher level of body mass index, and a shorter time from onset to admission. Multivariate logistic regression analysis revealed that the youth (age ≤40 years) (OR: 2.853, 95%CI: 1.061–7.668, p = .038) were prone to AKI, and lower estimated glomerular filtration rate (eGFR) (OR: 1.526, per 15-ml/min/1.73 m² decrease, 95%CI: 1.114–2.092; p = .009), higher diastolic blood pressure (DBP) (OR: 1.418, per 10-mmHg increase; 95%CI: 1.070–1.879; p = .015), and fasting blood glucose (FBG) ≥7 mmol/L on admission (OR: 2.592; 95%CI: 1.299–5.174; p = .007) were independent risk factors for AKI.

Conclusions

Higher incidence of AKI had been perceived in this study, most of them were young and middle-aged patients. Renopreventive measures should be considered in those high-risk patients with younger age, lower eGFR, higher DBP, and higher FBG on admission.

Scutellarin alleviates type 2 diabetes (HFD/low dose STZ)-induced cardiac injury through modulation of oxidative stress, inflammation, apoptosis and fibrosis in mice

BACKGROUND

Diabetes is a serious global health concern which severely affected public health as well as socio-economic growth worldwide. Scutellarin (SCU), a bioactive flavonoid, is known for its efficacious action against a range of ailments including cardiovascular problems. The present study was conducted to find out possible protective effect and its associated mechanisms of SCU on experimental type 2 diabetes-induced cardiac injury.

METHODS

Type 2 diabetes was induced by treating animals with high fat diet for 4 weeks and a single intraperitoneal dose (35 mg/kg body weight) of streptozotocin and diabetic animals received SCU (10 or 20 mg/kg/day) for 6 weeks.

RESULTS

Scutellarin attenuated type 2 diabetes-induced hyperglycemia, bodyweight loss, hyperlipidaemia, cardiac functional damage with histopathological alterations and fibrosis. Scutellarin treatment to type 2 diabetic mice ameliorated oxidative stress, inflammatory status and apoptosis in heart. Furthermore, the underlying mechanisms for such mitigation of oxidative stress, inflammation and apoptosis in heart involved modulation of Nrf2/Keap1 pathway, TLR4/MyD88/NF-κB mediated inflammatory pathway and intrinsic (mitochondrial) apoptosis pathway, respectively.

CONCLUSIONS

The current findings suggest that SCU is effective in protecting type 2 diabetes-induced cardiac injury by attenuating oxidative stress and inflammatory responses and apoptosis, and it is also worth considering the efficacious potential of SCU to treat diabetic cardiomyopathy patients.

LncRNA TUG1 attenuates ischaemia-reperfusion-induced apoptosis of renal tubular epithelial cells by sponging miR-144-3p via targeting Nrf2

Renal ischaemia/reperfusion (I/R) injury may induce kidney damage and dysfunction, in which oxidative stress and apoptosis play important roles. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are reported to be closely related to renal I/R, but the specific molecular mechanism is still unclear. The purpose of this research was to explore the regulatory effect of lncRNA TUG1 on oxidative stress and apoptosis in renal I/R injury. This research revealed that in renal I/R injury and hypoxia/reperfusion (H/R) injury in vitro, the expression level of lncRNA TUG1 was upregulated, and oxidative stress levels and apoptosis levels were negatively correlated with the expression level of lncRNA TUG1. Using bioinformatics databases such as TargetScan and microRNA.org, microRNA-144-3p (miR-144-3p) was predicted to be involved in the association between lncRNA TUG1 and Nrf2. This study confirmed that the level of miR-144-3p was significantly reduced following renal I/R injury and H/R injury in vitro, and miR-144-3p was determined to target Nrf2 and inhibit its expression. In addition, lncRNA TUG1 can reduce the inhibitory effect of miR-144-3p on Nrf2 by sponging miR-144-3p. In summary, our research shows that lncRNA TUG1 regulates oxidative stress and apoptosis during renal I/R injury through the miR-144-3p/Nrf2 axis, which may be a new treatment target for renal I/R injury.

Early type 1 diabetes aggravates renal ischemia/reperfusion-induced acute kidney injury

The present study aimed to investigate the interaction between early diabetes and renal IR-induced AKI and to clarify the mechanisms involved. C57BL/6J mice were assigned to the following groups: (1) sham-operated; (2) renal IR; (3) streptozotocin (STZ-55 mg/kg/day) and sham operation; and (4) STZ and renal IR. On the 12th day after treatments, the animals were subjected to bilateral IR for 30 min followed by reperfusion for 48 h, at which time the animals were euthanized. Renal function was assessed by plasma creatinine and urea levels, as well urinary protein contents. Kidney morphology and gene and protein expression were also evaluated. Compared to the sham group, renal IR increased plasma creatinine, urea and albuminuria levels and decreased Nphs1 mRNA expression and nephrin and WT1 protein staining. Tubular injury was observed with increased Havcr1 and Mki67 mRNA expression accompanied by reduced megalin staining. Renal IR also resulted in increased SQSTM1 protein expression and increased proinflammatory and profibrotic factors mRNA expression. Although STZ treatment resulted in hyperglycemia, it did not induce significant changes in renal function. On the other hand, STZ treatment aggravated renal IR-induced AKI by exacerbating renal dysfunction, glomerular and tubular injury, inflammation, and profibrotic responses. Thus, early diabetes constitutes a relevant risk factor for renal IR-induced AKI.

The semaphorin 4A-neuropilin 1 axis alleviates kidney ischemia reperfusion injury by promoting the stability and function of regulatory T cells

Previous studies have suggested the role of CD4⁺Foxp3⁺ regulatory T cells (Tregs) in protection against kidney ischemia reperfusion injury via their immunosuppressive properties. Unfortunately, the associated mechanisms of Tregs in kidney ischemia reperfusion injury have not been fully elucidated. Semaphorin 4A (Sema4A) is essential for maintaining the immunosuppressive capacity of Tregs in tumors. However, whether Sema4A can alleviate kidney ischemia reperfusion injury through Tregs has not yet been demonstrated. Here, we investigated the effect and mechanism of Sema4A on the development of kidney ischemia reperfusion injury. Administration of recombinant human Sema4A-Fc chimera protein prior to ischemia reperfusion injury promoted the expansion and function of Tregs and decreased the accumulation of neutrophils and proinflammatory macrophages thereby attenuating functional and histological injury of the injured kidneys. Depletion of Tregs abrogated the protective effect of Sema4A on kidney ischemia reperfusion injury, suggesting Tregs as the main target cell type for Sema4A in the development of this injury. Mechanistically, Sema4A bound to neuropilin 1 (Nrp1), a cell surface receptor for Sema4A and other ligands and a key regulator of Tregs, which then promoted recruitment of phosphatase and tensin homologue and suppressed the Akt-mTOR pathway in Foxp3^Cre mice but not in Nrp1^f/fFoxp3^Cre mice. Consistently, Treg-specific deletion of Nrp1 blocked the effect of Sema4A on the expansion and function of Treg cells. Thus, our results demonstrate that the Sema4A-Nrp1 axis alleviates the development of ischemia reperfusion injury by promoting the stability and function of Tregs in mouse kidneys.

Dynamic regulation of anti-oxidation following donation repairing after circulatory determined death renal transplantation with prolonged non-heart-beating time

Donation after circulatory-determined death (DCD) is an important part of renal transplantation. Therefore, DCD renal transplantation animal model should be established to study the mechanism of organ injury. Here, we established a stable DCD rat renal transplantation model and investigated the dynamic regulation of graft self-repairing and antioxidant capacities with different non-heart-beating times (NHBTs). Male Sprague-Dawley rats were randomly divided into four groups with the NHBT of the donors from 0 to 15, 30, and 45 minutes. Recipients in long NHBT groups had a significantly lower survival rate and poorer graft function than those in short NHBT groups. Grafts from the 15-minute and 30-minute NHBT groups showed light and severe injury respectively at an early stage after transplantation and recovered within 7 days after transplantation, whereas the self-repairing of the grafts in the 45-minute NHBT group was delayed. The expressions of proliferating cell nuclear antigen (PCNA) and von Willebrand factor (vWF) were dependent on NHBT. The expression of antioxidant proteins paralleled graft recovery. In conclusion, the recipients can up-regulate antioxidant capacity to enhance graft self-repairing in DCD renal transplantation. Prolonged NHBT can delay the self-repairing and antioxidation of grafts.

Knockdown of ANGPTL2 Protects Renal Tubular Epithelial Cells Against Hypoxia/Reoxygenation-Induced Injury via Suppressing TLR4/NF-κB Signaling Pathway and Activating Nrf2/HO-1 Signaling Pathway

Renal ischemia/reperfusion (I/R) injury is a particular threat faced by clinicians in kidney transplantation. Previous studies have confirmed the importance of oxidative stress and inflammation in the pathogenesis of I/R injury. Angiopoietin-like protein 2 (ANGPTL2) belongs to the angiopoietin-like family and has been found to be involved in the regulation of kidney function as well as oxidative and inflammatory response. In the present study, we aimed to evaluate the role of ANGPTL2 in renal I/R injury in vitro. The human proximal tubular epithelial cell line (HK-2 cells) was subjected to hypoxia/ reoxygenation (H/R) to mimic I/R injury in vitro. We found that the expression level of ANGPTL2 was markedly increased in H/R-induced HK-2 cells. Knockdown of ANGPTL2 improved the decreased cell viability of HK-2 cells in response to H/R stimulation. Knockdown of ANGPTL2 significantly inhibited the H/R-caused increase in levels of reactive oxygen species, malondialdehyde, and proinflammatory cytokines, including interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha, as well as a decrease in superoxide dismutase activity in the HK-2 cells. Besides, the increased bax expression and caspase-3 activity and decreased bcl-2 expression in H/R-induced HK-2 cells were also attenuated by knockdown of ANGPTL2. Moreover, ANGPTL2 overexpression showed the opposite effects. Further mechanism investigations proved that the activation of Nrf2/HO-1 signaling pathway and the inhibition of toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway were both implicated in the renal-protective effects of ANGPTL2 knockdown on H/R-induced HK-2 cells. Collectively, these findings suggested that ANGPTL2 might be a new possible target for the treatment and prevention of renal I/R injury.

Lactobacillus acidophilus ATCC 4356 Alleviates Renal Ischemia-Reperfusion Injury Through Antioxidant Stress and Anti-inflammatory Responses and Improves Intestinal Microbial Distribution

Background: Ischemia–reperfusion injury (IRI) is one of the main causes of acute kidney injury. Our previous results have shown that anti-oxidative stress decreased in the renal IRI model. This study aimed to investigate the effect of Lactobacillus acidophilus ATCC 4356 on oxidative stress, inflammation, and intestinal flora in renal IRI.

Methods: The model of renal IRI was established by cross-clamping the renal pedicle with non-traumatic vascular forceps. H&E staining was applied to observe the damage of kidney tissue in each group. The concentrations of serum blood urea nitrogen (BUN), creatinine (Cre), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) were detected by biochemical kit. ELISA measured the concentrations of interleukin (IL)-1β, IL-8, IL-4, and IL-10. qRT-PCR was performed to detect molecular expressions of ATCC 4356, oxidative stress-related factors [nuclear factor-related factor 2 (Nrf2), heme oxygenase 1 (HO-1)], inflammatory factors [tumor necrosis factor (TNF)-α, IL-1β, IL-8, interferon (IFN)-γ, IL-4, IL-10], and apoptosis-related factors [caspase 3, Bax, Bcl2, high-mobility group box protein 1 (HMGB1)]. Except for ATCC 4356, the protein expression of the above indicators was detected by Western blot. The apoptosis level of renal tissue cells was detected by TdT-mediated dUTP nick end labeling (TUNEL). 16S rDNA gene sequencing was used to detect the changes of microbial species in the contents of the duodenum and screen out the differentially expressed flora.

Results: Both the glomeruli and renal tubules of ischemia/reperfusion (I/R) mice were severely damaged. H&E result displayed that L. acidophilus ATCC 4356 attenuated the infiltration of inflammatory cells caused by I/R. ATCC 4356 reduced the high expression of BUN and Cre in I/R mice with a dose effect. It also reduced the high expression of MDA, TNF-α, IL-1β, IL-8, IFN-γ, caspase 3, Bax, and HMGB1 in I/R mice, while it increased the low expression of SOD, GSH, Nrf2, HO-1, IL-4, IL-10, and Bcl2 in I/R mice. ATCC 4356 inhibited the high level of apoptosis in the kidney tissue of I/R mice. In IRI mice, the top 3 different gut microbiota were Helicobacter, cultivated_bacterium, and k__Bacteria_ASV_3 compared with sham mice. Oral L. acidophilus ATCC 4356 reversed this change.

Conclusion:L. acidophilus ATCC 4356 attenuated renal IRI through anti-oxidative stress and anti-inflammatory response and improved the intestinal microbial distribution.

Role of TLR4/MyD88/NF-κB signaling in heart and liver-related complications in a rat model of type 2 diabetes mellitus

Aims

To analyze expression of members of the Toll-like receptor (TLR)4/myeloid differentiation primary response 88 (MyD88)/nuclear factor (NF)-κB signaling pathway in the heart and liver in a rat model of type 2 diabetes mellitus (T2DM). Our overall goal was to understand the underlying pathophysiological mechanisms.

Methods

We measured fasting blood glucose (FBG) and insulin (FINS) in a rat model of T2DM. Expression of members of the TLR4/MyD88/NF-κB signaling pathway as well as downstream cytokines was investigated. Levels of mRNA and protein were assessed using quantitative real-time polymerase chain reaction and western blotting, respectively. Protein content of tissue homogenates was assessed using enzyme-linked immunosorbent assays.

Results

Diabetic rats had lower body weights, higher FBG, higher FINS, and higher intraperitoneal glucose tolerance than normal rats. In addition, biochemical indicators related to heart and liver function were elevated in diabetic rats compared with normal rats. TLR4 and MyD88 were involved in the occurrence of T2DM as well as T2DM-related heart and liver complications. TLR4 caused T2DM-related heart and liver complications through activation of NF-κB.

Conclusions

TLR4/MyD88/NF-κB signaling induces production of tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1, leading to the heart- and liver-related complications of T2DM.

Endothelium-dependent remote signaling in ischemia and reperfusion: Alterations in the cardiometabolic continuum

Intact endothelial function plays a fundamental role for the maintenance of cardiovascular (CV) health. The endothelium is also involved in remote signaling pathway-mediated protection against ischemia/reperfusion (I/R) injury. However, the transfer of these protective signals into clinical practice has been hampered by the complex metabolic alterations frequently observed in the cardiometabolic continuum, which affect redox balance and inflammatory pathways. Despite recent advances in determining the distinct roles of hyperglycemia, insulin resistance (InR), hyperinsulinemia, and ultimately diabetes mellitus (DM), which define the cardiometabolic continuum, our understanding of how these conditions modulate endothelial signaling remains challenging. It is widely accepted that endothelial cells (ECs) undergo functional changes within the cardiometabolic continuum. Beyond vascular tone and platelet-endothelium interaction, endothelial dysfunction may have profound negative effects on outcome during I/R. In this review, we summarize the current knowledge of the influence of hyperglycemia, InR, hyperinsulinemia, and DM on endothelial function and redox balance, their influence on remote protective signaling pathways, and their impact on potential therapeutic strategies to optimize protective heterocellular signaling.

Sappanone A Protects Against Inflammation, Oxidative Stress and Apoptosis in Cerebral Ischemia-Reperfusion Injury by Alleviating Endoplasmic Reticulum Stress

Endoplasmic reticulum stress is an important contributor to the cerebral ischemic injury. Sappanone A (SA), a kind of natural homoisoflavanone extracted from Caesalpinia sappan L, has been evidenced to exhibit anti-inflammatory and antioxidative properties. The present study aimed to investigate the potential neuroprotective effects of SA in cerebral ischemia-reperfusion injury. The potential neuroprotective effect of SA was tested in a rat model of middle cerebral artery occlusion (MCAO) allowing reperfusion and PC12 cell model of oxygen-glucose deprivation and reperfusion (OGD/R). Post-ischemic neuronal injury was evaluated by 2, 3, 5-triphenyltetrazolium chloride (TTC) and hematoxylin-eosin (H&E) staining. The levels of inflammatory factors and oxidative stress-related markers were detected using corresponding kits. Cell apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) or flow cytometry, and the expression of apoptosis-associated proteins was determined using western blot analysis. Subsequently, endoplasmic reticulum stress-related proteins were detected through western blot analysis, and CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) was overexpressed to confirm the contribution of endoplasmic reticulum stress inhibition by SA to the neuroprotective effects post OGD/R. Results revealed that SA was effective in ameliorating cerebral infarction and pathological injuries post-reperfusion following MCAO, which is associated with reduced inflammation, oxidative stress, and cell apoptosis by SA in the brain. Consistently, these neuroprotective effects of SA post ischemia-reperfusion were also observed in a PC12 cell model of OGD/R. Importantly, endoplasmic reticulum stressors, including the CHOP, the 78 kDa glucose-regulated protein 78 (GRP78), and phosphorylated eukaryotic initiation factors 2α (EIF-2α), were significantly downregulated by SA, while CHOP overexpression attenuated the beneficial effects of SA on inflammation, oxidative stress, and apoptosis in OGD/R-induced PC12 cells. These results demonstrated that SA alleviates endoplasmic reticulum stress, ameliorating inflammation, oxidative stress, and apoptosis, and thereby serves as therapeutic potential for protection against cerebral ischemia-reperfusion injury in ischemic stroke.

Protective Role of Nrf2 in Renal Disease

Chronic kidney disease (CKD) is one of the fastest-growing causes of death and is predicted to become by 2040 the fifth global cause of death. CKD is characterized by increased oxidative stress and chronic inflammation. However, therapies to slow or prevent CKD progression remain an unmet need. Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that plays a key role in protection against oxidative stress and regulation of the inflammatory response. Consequently, the use of compounds targeting Nrf2 has generated growing interest for nephrologists. Pre-clinical and clinical studies have demonstrated that Nrf2-inducing strategies prevent CKD progression and protect from acute kidney injury (AKI). In this article, we review current knowledge on the protective mechanisms mediated by Nrf2 against kidney injury, novel therapeutic strategies to induce Nrf2 activation, and the status of ongoing clinical trials targeting Nrf2 in renal diseases.

Hydrogen sulfide restores sevoflurane postconditioning mediated cardioprotection in diabetic rats: Role of SIRT1/Nrf2 signaling-modulated mitochondrial dysfunction and oxidative stress

Diabetic hearts are vulnerable to myocardial ischemia/reperfusion injury (IRI), but are insensitive to sevoflurane postconditioning (SPC), activating peroxiredoxins that confer cardioprotection. Previous studies have demonstrated that hydrogen sulfide (H₂ S) can suppress oxidative stress of diabetic rats through increasing the expression of silent information regulator factor 2-related enzyme 1 (SIRT1), but whether cardioprotection by SPC can be restored afterward remains unclear. Diabetic rat was subjected to IRI (30 min of ischemia followed by 120 min reperfusion). Postconditioning treatment with sevoflurane was administered for 15 min upon the onset of reperfusion. The diabetic rats were treated with GYY4137 (H₂ S donor) 5 days before the experiment. Myocardial infarct size, mitochondrial structure and function, ATP content, activities of complex I-IV, marker of oxidative stress, SIRT1, nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADPH Oxidase-2 (Nox-2) protein expression were detected after reperfusion, and cardiac function was evaluated by echocardiography at 24 h after reperfusion. After H₂ S activated SIRT1 in the impaired myocardium of diabetic rats, SPC significantly upregulated the expression of Nrf2 and its downstream mediator HO-1, thus reduced the expression of Nox-2. In addition, H₂ S remarkably increased cytoplasmic and nuclear SIRT1 which was further enhanced by SPC. Furthermore, H₂ S combined with SPC reduced the production of reactive oxygen species, increased the content of ATP, and maintained mitochondrial enzyme activity. Finally, myocardial infarct size and myocardium damage were decreased, and cardiac function was improved. Taken together, our study proved that H₂ S could restore SPC-induced cardioprotection in diabetic rats by enhancing and promoting SIRT1/Nrf2 signaling pathway mediated mitochondrial dysfunction and oxidative stress.

Protective effects of Artemisia judaica extract compared to metformin against hepatorenal injury in high-fat diet/streptozotocine-induced diabetic rats

Diabetes mellitus (DM) is one of the most dangerous incurable diseases that affects a large number of people worldwide. Artemisia species have various protective activities and are widely used for the control of diabetes in folkloric medicine. Therefore, the current study was designed to illustrate the protective effect of oral administration of Artemisia judaica extract (AjE) against hepatorenal damage in a high-fat diet/streptozotocin (HFD/STZ) rat model of hyperlipidemia and hyperglycemia. Animals were divided into five groups-control, AjE, HFD/STZ, HFD/STZ-AjE (300 mg/kg), and HFD/STZ-MET (100 mg/kg)-and treated daily for 28 days. The results revealed that STZ-injected rats showed marked hyperglycemia and hypoinsulinemia in addition to high levels of cholesterol, triglycerides, and low- and high-density lipoproteins compared to control rats. Significant elevations in hepatic (AST and ALT) and renal (urea, uric acid, and creatinine) function markers were observed in the serum of diabetic rats. Additionally, STZ injection caused remarkable elevations in lipid peroxidation and nitric oxide levels as well as suppression of antioxidant markers (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione). Marked elevations in TNF-α and Bax levels with a decline in Bcl-2 levels were detected after STZ injection. Furthermore, TGF-β1 expression levels were significantly upregulated in the liver and kidney tissues. Rats that received AjE or MET showed significant improvement in most of the aforementioned parameters, and the protective efficacy was higher for AjE than for MET. Histopathological screening confirmed the biochemical findings. Conclusively, our results illustrated the antihyperglycemic, antihyperlipidemic, antioxidant, anti-inflammatory, and antiapoptotic activities of AjE against hepatorenal injury in HFD/STZ-induced diabetes.

Nrf-2 as a therapeutic target in acute kidney injury

Multifaceted cellular pathways exhibit a crucial role in the preservation of homeostasis at the molecular, cellular, and organism levels. One of the most important of these protective cascades is Nuclear factor E2-related factor (Nrf-2) that regulates the expression of several genes responsible for cellular detoxification, antioxidant function, anti-inflammation, drug/xenobiotic transportation, and stress-related factors. A growing body of evidence provides information regarding the protective role of Nrf-2 against a number of kidney diseases. Acute kidney injury (AKI) is a substantial clinical problem that causes a huge social burden. In the kidneys, Nrf-2 exerts a dynamic role in improving the injury triggered by inflammation and oxidative stress. Understanding of the exact molecular mechanisms underlying AKI is vital in order to determine the equilibrium between renal adaptation and malfunction and thus reduce disease progression. This review highlights the role of Nrf-2 targeting against AKI and provides evidence that targeting Nrf-2 to prevail oxidative damage and its consequences might exhibit protective effects in kidney diseases.

Nobiletin alleviates ischemia/reperfusion injury in the kidney by activating PI3K/AKT pathway

Recent studies have demonstrated that nobiletin (NOB) displays anti-oxidative and anti-apoptotic efficacies against multiple pathological insults. However, the potential effects of NOB on the injury caused by ischemia and reperfusion (I/R) in the kidney remain undetermined. In the present study, I/R injury was elicited by right kidney removal and left renal pedicel clamping for 45 min, followed by reperfusion for 24 h. NOB was added at the start of reperfusion. Histological examination, detection of biomarkers in plasma, and measurement of apoptosis induced by endoplasmic reticulum stress (ERS) were used to evaluate renal injury. Additionally, the PI3K/AKT inhibitor LY294002 was also used in mechanistic experiments. NOB pre-treatment significantly reduced renal damage caused by I/R injury, as indicated by decreased serum levels of creatine, blood urea nitrogen and tubular injury scores. Furthermore, NOB inhibited elevated ERS-associated apoptosis, as evidenced by reduced apoptotic rates and ERS-related signaling molecules (such as, C/EBP homologous protein, caspase-12 and glucose-regulated protein of 78 kDa). NOB increased phosphorylation of proteins in the PI3K/AKT pathway. The inhibition of PI3K/AKT signaling with pharmacological inhibitors could reverse the beneficial effects of NOB during renal I/R insult. In conclusion, NOB pre-treatment may alleviate I/R injury in the kidney by inhibiting reactive oxygen species production and ERS-induced apoptosis, partly through the PI3K/AKT signaling pathway.

Nuclear factor erythroid-2 related factor 2 inhibits human disc nucleus pulpous cells apoptosis induced by excessive hydrogen peroxide

OBJECTIVE Nuclear factor erythroid-2 related factor 2 (Nrf2)/ antioxidant response element (ARE) is a novel defensive pathway involved in the oxidative and chemical stress of cells. The aim of the study was to explore the role of Nrf2 on the apoptosis of human disc nucleus pulpous cells induced by hydrogen peroxide (H2O2). METHODS The degeneration model of human intervertebral disc nucleus pulpous cells was established. The expression of Nrf2 was interfered with using sulforaphane (SFN); for that end, three groups were established: a blank group (H2O2-/SFN-), control group (H2O2+/SFN-), and an experimental group (H2O2+/SFN+). CCK8, Hoechst 33258 living cell staining was used to detect reactive oxygen species (ROS) content. RESULTS The apoptotic rates of the three groups were [(0.40±0.46)%], [(25.98±11.28)%], and [(3.83±2.06)%, respectively. The difference was statistically significant (p<0.05). The relative content of ROS in the three groups was [(100±7)%], [(1538±91)%], and [(818±63)%]; the difference was statistically significant (p<0.05). In Western blotting, Nrf2 content in the experimental group was higher than that in the control group. CONCLUSION Nrf2 exists in the nucleus pulpous cells of human intervertebral discs, which is related to the degeneration of the intervertebral disc. It has negative feedback regulation and can prevent the degeneration of the intervertebral disc by inhibiting the apoptosis of nucleus pulpous cells of human intervertebral discs caused by excessive ROS, which provides a new intervention strategy for the prevention and treatment of the degeneration of intervertebral discs.

Tert-butylhydroquinone mitigates Carbon Tetrachloride induced Hepatic Injury in mice

Tert-butylhydroquinone (tBHQ) is an antioxidant compound that exhibits cytoprotective effect in many tissues under pathological condition. However, its role in carbon tetrachloride (CCL4) induced liver injury is still unclear. Here we established a carbon tetrachloride induced hepatic injury model in mice to determine whether tBHQ can mitigate CCL4 induced liver damage. In our study, we found tBHQ exhibited protective effects in CCL4 treated mice model. TBHQ markedly improved hepatic function and decreased hepatic histopathological damage in vivo. In addition, tBHQ reduced levels of pro-inflammatory cytokines in mice model. Moreover, tBHQ mitigated apoptosis of hepatocytes, oxidative stress and lipid peroxidation in vivo and in vitro. We also found the possible mechanism of protective effects of tBHQ was associated with activation of Nrf2/ heme oxygenase-1 (HO-1) pathway. In conclusion, our study revealed tBHQ can be a potential therapeutic drug in treatment of acute hepatic injury.

Ameliorative Effects of Bredemolic Acid on Markers Associated with Renal Dysfunction in a Diet-Induced Prediabetic Rat Model

Recently, studies have shown that renal dysfunction is associated not only with overt diabetes but also with the preceding stage known as prediabetes. Diet and pharmacological interventions are the therapeutic approaches to managing prediabetes, but the compliance in combining the two interventions is low. Hence, the efficacy of pharmacological intervention is reduced without diet modification. In our previous study, we established that bredemolic acid (BA) ameliorated glucose homeostasis via increased GLUT 4 expression in the skeletal muscle of prediabetic rats in the absence of diet intervention. However, the effects of bredemolic acid on renal function in prediabetic condition are unknown. Therefore, this study was aimed at investigating the ameliorative effects of bredemolic acid on renal dysfunction in a diet-induced prediabetic rat model. Thirty-six Sprague-Dawley male rats (150-180 g) were divided into two groups: the nonprediabetic (n = 6) and prediabetic (n = 30) groups which were fed normal diet (ND) and high-fat high-carbohydrate (HFHC) diet, respectively, for 20 weeks. After the 20^th week, the prediabetic groups were subdivided into prediabetic control (PD) and 4 other prediabetic groups which were treated with either BA (80 mg/kg) or metformin (MET, 500 mg/kg) for further 12 weeks (21^st to 32^nd). Plasma, urine, and kidney samples were collected for biochemical analysis. The untreated prediabetic (PD) rats presented increased fluid intake and urine output; increased creatinine, urea, and uric acid plasma concentrations; albuminuria; proteinuria; sodium retention; potassium loss; increased aldosterone and kidney injury molecule (KIM-1) concentration; and increased urinary podocin mRNA expression. However, BA administration attenuated the renal markers and oxidative stress and decreased the urinary podocin mRNA expression. In conclusion, BA administration, regardless of diet modification, attenuates renal dysfunction in an experimentally induced prediabetic state.

Resveratrol inhibits TNF-α-induced inflammation to protect against renal ischemia/reperfusion injury in diabetic rats

Purpose

To examine effects of resveratrol on renal ischemia/ reperfusion injury (I/R) in a streptozotocin (STZ)-induced diabetic rat model.

Methods

Twenty-four male Sprague Dawley rats were treated with STZ injection for the development of diabetes, and divided into the following groups: Sham group, I/R group and Resveratrol group (n=8). Resveratrol (RSV) was administered at a dose of 10 mg.kg-1.d-1 fourteen days prior to suffering from I/R. Renal function, histology, SOD, MDA, TUNEL assay and expression of TNF-α, IL-1β, NF-κB-P65, COX-2 and Caspase3, Bcl2 and Bax were analyzed.

Results

Administration of RSV significantly reduced the serum levels of renal dysfunction and injury markers, including creatinine, blood urea nitrogen and MDA; in the other hand, it significantly increased the serum levels of SOD. The protective effect of RSV was also reflected on histologic evaluation. RSV reduced the number of apoptotic cells as determined by TUNEL assay. RSV significantly reduced the protein expression of TNF-α, IL-1β, NF-κB-P65, COX-2 and Caspase3, and Bax. Meanwhile, RSV significantly increased the protein expression of Bcl2.

Conclusion

RSV attenuated I/R-induced renal injury in diabetic rats through the modulation of oxidative stress and TNF-α-stimulated inflammation.

Tert-butylhydroquinone preserve testicular steroidogenesis and spermatogenesis in cisplatin-intoxicated rats by targeting oxidative stress, inflammation and apoptosis

Cisplatin (Cis) is an effective chemotherapeutic intervention against many cancer types. However, the oxidative stress-related toxicities associated with cancer cell resistance-induced dose scaling has limited its long-term use. In the present study, we explored the benefits of the antioxidant, tert-butylhydroquinone (tBHQ; 50 mg/kg b.w./day, for 14 days) against Cis single dose injection (7 mg/kg b.w., i.p on Day 8), on testicular toxicity of male Wistar rats. Cis triggered testicular and epididymal oxidative stress, testicular inflammation (upregulated NF-κB, TNF-α and IL-1β mRNA levels, and downregulated IL-10 mRNA level), increased testicular apoptosis (increased Bax/Bcl2 and caspase-3 mRNA levels) and decreased testicular germ cells proliferation. Further, Cis decreased testicular steroidogenesis (decreased expression of StAR, CYP11A1, 3β-HSD and 17β-HSD mRNA and proteins) and decreased follicle stimulating hormone, luteinizing hormone and testosterone levels. Cis also decreased sperm count, motility, viability, normal morphology and Johnsen score. However, intervention with tBHQ significantly decreased oxidative stress by upregulating Nrf2 gene, suppressed inflammation, apoptosis and increased testicular germ cells proliferation. tBHQ also increased steroidogenesis and improved sperm parameters. Taken together, tBHQ improves steroidogenesis and spermatogenesis in Cis-intoxicated rats by improving antioxidant status, dampening inflammation and apoptosis, thus improving the proliferative capacity of spermatogenic cells.

Effect of oleuropein on oxidative stress, inflammation and apoptosis induced by ischemia-reperfusion injury in rat kidney

AIMS

This study aimed to evaluate the effect of oleuropein (OLE), the main phenolic compound present in olive leaves, on kidney ischemia-reperfusion injury (IRI) and to explore the underlying protective mechanism.

MAIN METHODS

Rat kidneys were subjected to 60 min of bilateral warm ischemia followed by 120 min of reperfusion. OLE was administered orally 48 h, 24 h and 30 min prior to ischemia at doses of 10, 50 and 100 mg/kg body weight. The creatinine, urea, uric acid concentrations and lactate dehydrogenase (LDH) activity in plasma were evaluated. Oxidative stress and inflammation parameters were also assessed. Renal expression of AMP-activated protein kinase (p-AMPK), endothelial nitric oxide synthase (eNOS), mitogen-activated protein kinases (MAPK), inflammatory proteins and apoptotic proteins were evaluated using Western blot.

KEY FINDINGS

Our results showed that OLE at 50 mg/kg reduced kidney IRI as revealed by a significant decrease of plasmatic creatinine, urea, uric acid concentrations and LDH activity. In parallel, OLE up-regulated antioxidant capacities. Moreover, OLE diminished the level of CRP and the expression of cyclooxygenase 2 (COX-2). Finally, OLE enhanced AMPK phosphorylation as well as eNOS expression whereas MAPK, and cleaved caspase-3 implicated in cellular apoptosis were attenuated in the ischemic kidneys.

SIGNIFICANCE

In conclusion, this study shows that OLE could be used as therapeutic agent to reduce IRI through its anti-oxidative, anti-inflammatory and anti-apoptotic properties.