Hydrogen sulfide renal protective effects: possible link between hydrogen sulfide and endogenous carbon monoxide in a rat model of renal injury

A combination of generated hydrogen sulfide and nitric oxide activity has a potentiated protectant effect against cisplatin induced nephrotoxicity

Aim

Hydrogen sulfide and nitric oxide possess cytoprotective activity and in vivo, they are generated from exogenous sodium hydrosulfide and L-arginine respectively. Cisplatin is a major chemotherapeutic agent used to treat cancer and has a high incidence of nephrotoxicity as a side effect. The study aim was to explore the effects of NaHS and L-arginine or their combination on cisplatin induced nephrotoxicity in rats.

Methods

Wistar Kyoto rats were given a single intraperitoneal dose of cisplatin (5 mg/kg) followed either by NaHS (56 μmol/kg, i. p.), L-arginine (1.25 g/L in drinking water) or their combination daily for 28-days. Post-mortem plasma, urine and kidney samples were collected for biochemical assays and histopathological analysis.

Results

Cisplatin decreased body weights and increased urinary output, while plasma creatinine and urea levels were elevated, but sodium and potassium concentrations were diminished. The renal function parameters, blood urea nitrogen and creatinine clearance, were raised and decreased respectively. Regarding markers of reactive oxygen species, plasma total superoxide dismutase was reduced, whereas malondiadehyde was augmented.Cisplatin also diminished plasma and urinary H2S as well as plasma NO, while NaHS and L-arginine counteracted this activity on both redox-active molecules. Cisplatin cotreatment with NaHS, and/or L-arginine exhibited a reversal of all other measured parameters.

Conclusion

In current study, NaHS and L-arginine as monotherapy protected the rats from cisplatin-induced nephrotoxicity but the combination of both worked more effectively suggesting the augmented anti-inflammatory and antioxidative potential of test treatments when administered together.

Curcumin protects against lamotrigine-induced chronic ovarian and uterine toxicity in rats by regulating PPAR-γ and ROS production

Lamotrigine (LTG) is an antiepileptic drug with possible adverse effects on the female reproductive system. Curcumin was declared to improve ovarian performance. Therefore, this study aimed to clarify ovulatory dysfunction (OD) associated with LTG and the role of curcumin in ameliorating this dysfunction. Adult female Wister albino rats were assigned into four groups: negative control (received saline), positive control (received curcumin only), LTG, and LTG with curcumin groups. Drugs were administered for 90 days. The hormonal profile, including testosterone, estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone, in addition to the lipid profile and glycemic analysis, were tested. Oxidative stress biomarkers analysis in the ovaries and uterus and peroxisome proliferator-activated receptor-γ (PPAR-γ) gene expression were also included. Histopathological examination of ovarian and uterine tissues and immunohistochemical studies were also performed. Curcumin could improve the OD related to chronic LTG intake. That was proved by the normalization of the hormonal profile, glycemic control, lipidemic status, oxidative stress markers, and PPAR-γ gene expression. The histopathological and immunohistochemical examination of ovarian and uterine tissues revealed an improvement after curcumin administration. The results describe an obvious deterioration in ovarian performance with LTG through the effect on lipidemic status, PPAR-γ gene, and creating an oxidative stress condition in the ovaries of chronic users, with a prominent improvement with curcumin addition to the treatment protocol.

The effects of CORM3 or NaHS on the oxidative stress caused by chronic kidney disease in rats: potential interaction between CO and H2S signaling pathway

Neurotoxicity is implicated as a severe complication of chronic kidney disease (CKD). Accumulation of urea and other toxic compounds leads to oxidative stress, inflammation and destruction of the blood-brain barrier. Carbon monoxide (CO) and hydrogen sulfide (H2S) have been shown to have anti-inflammatory, anti-apoptotic, and anti-proliferative properties. The aims of the present study were evaluated the protective effects of CO-releasing molecule (CORM3) and H2S donor (NaHS) on oxidative stress and neuronal death induced by CKD in the hippocampus and prefrontal cortex by considering interaction between CO and H2S on CBS expression. CORM3 or NaHS significantly compensated deficits in the antioxidant defense mechanisms, suppressed lipid peroxidation and reduced neuronal death in hippocampus and prefrontal cortex and improvement the markers of renal injury that induced by CKD. In addition, CORM3 or NaHS significantly improved CBS expression which were reduced by CKD. However, improving effects of CORM3 on antioxidant defense mechanisms, lipid peroxidation, neuronal death, renal injury and CBS expression were prevented by amino-oxy acetic acid (AOAA) (CBS inhibitor) and reciprocally improving effects of NaHS on all above indices were prevented by zinc protoporphyrin IX (Znpp) (HO-1 inhibitor). In conclusion, this study demonstrated that formation of CO and H2S were interdependently improved CKD-induced oxidative stress and neuronal death, which is may be through increased expression of CBS.

Bafilomycin A1 inhibits SARS-CoV-2 infection in a human lung xenograft mouse model

Coronavirus disease 2019 is a global pandemic caused by SARS-CoV-2. The emergence of its variant strains has posed a considerable challenge to clinical treatment. Therefore, drugs capable of inhibiting SARS-CoV-2 infection, regardless of virus variations, are in urgently need. Our results showed that the endosomal acidification inhibitor, Bafilomycin A1 (Baf-A1), had an inhibitory effect on the viral RNA synthesis of SARS-CoV-2, and its Beta and Delta variants at the concentration of 500 nM. Moreover, the human lung xenograft mouse model was used to investigate the anti-SARS-CoV-2 effect of Baf-A1. It was found that Baf-A1 significantly inhibited SARS-CoV-2 replication in the human lung xenografts by in situ hybridization and RT-PCR assays. Histopathological examination showed that Baf-A1 alleviated SARS-CoV-2-induced diffuse inflammatory infiltration of granulocytes and macrophages and alveolar endothelial cell death in human lung xenografts. In addition, immunohistochemistry analysis indicated that Baf-A1 decreased inflammatory exudation and infiltration in SARS-CoV-2-infected human lung xenografts. Therefore, Baf-A1 may be a candidate drug for SARS-CoV-2 treatment.

Dipeptidyl peptidase-4 inhibitor: Sitagliptin down-regulated toll-like receptor 4 signaling pathway to reduce uterine injury in rats

OBJECTIVES

Uterine ischemia is a common problem with ongoing controversy about its pathogenesis and prevention. The present study aimed to investigate the protective role of sitagliptin against uterine ischemia-reperfusion injury (IRI).

MATERIALS AND METHODS

Rats were allocated into 4 groups: control, sitagliptin (SIT) (5 mg/kg), IR; ischemia was induced followed by reperfusion, and IR+SIT; SIT was administered 1 hr before IRI. Uteri were removed for histopathological and biochemical observations. Malondialdehyde (MDA), total nitrites (NOx), reduced glutathione (GSH), superoxide dismutase (SOD) activity, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and toll-like receptor 4 (TLR4) were all measured. Hematoxylin and eosin (H&E) stain, Periodic acid-Schiff stain (PAS), and caspase-3 immunostaining were applied.

RESULTS

In the IR+SIT group; NOx, GSH, and SOD activities increased significantly. Meanwhile, the levels of MDA, TNF-α, IL-6, TLR4, and caspase-3 immunoexpression showed a significant reduction, as compared with the IR group. In the IR+SIT group, an improvement in the histopathological picture was noticed.

CONCLUSION

The results showed that sitagliptin confers protection against uterine IRI through anti-oxidant, anti-inflammatory, and anti-apoptotic effects with a possible role for TLR4.

Thymol exerts antioxidant, anti-inflammatory, and anti-apoptotic protective effects against gentamicin nephrotoxicity in rats

The renoprotective effect of thymol (TML) was investigated in rats challenged with gentamicin (GN). Rats received TML (20 mg/kg/day, p.o.) for 15 days, and GN (80 mg/kg/day, i.p.) starting from the 8th day. TML significantly lowered serum creatinine and neutrophil gelatinase-associated lipocalin, and renal malondialdehyde, nitric oxide, tumor necrosis factor-α, interleukin-18, Bax, caspase-3, and caspase-9 in GN-challenged rats. In addition, TML caused a significant increment of renal total antioxidant capacity in rats received GN. Moreover, TML significantly ameliorated GN-induced histopathological kidney tissue injury, and significantly decreased nuclear factor-κB p65 and kidney injury molecule-1 expressions in kidneys of GN-challenged rats. It was concluded that TML guarded against CN-induced nephrotoxicity in rats via inhibition of oxidative stress, inflammation, and apoptosis.

Exogenous H2S Ameliorates High Salt-Induced Hypertension by Alleviating Oxidative Stress and Inflammation in the Paraventricular Nucleus in Dahl S Rats

Hydrogen sulfide (H₂S) is an important gaseous signaling molecule that regulates cardiovascular activity in animals. The hypothalamic paraventricular nucleus (PVN) is a major integrative region involved in blood pressure (BP) regulation. We explored whether exogenous H₂S application by intraperitoneal injection of sodium hydrosulfide (NaHS) alleviates BP increase induced by a high salt diet (HSD) and the role of PVN in Dahl salt-sensitive (Dahl S) rats. Dahl S rats were divided into four groups according to diet regime (normal salt diet [NSD] and HSD) and treatment method (daily intraperitoneal NaHS or saline injection). We monitored BP, food and water intake, and body weight for 8 weeks. Plasma, kidney, and brain tissues were collected at the end of the experiment. We found that exogenous H₂S not only delayed BP elevation but also attenuated the increase in the levels of norepinephrine, cystatin C, and blood urea nitrogen in the plasma of Dahl S rats with an HSD. Furthermore, H₂S enhanced the total antioxidant capacity, superoxide dismutase, and glutathione peroxidase in the PVN. Exogenous H₂S attenuated the protein expression of the nuclear factor-κB pathway and proinflammatory cytokines, which were significantly higher in the PVN in rats with an HSD than in rats with an NSD. Additionally, exogenous H₂S relieved PVN neuronal apoptosis induced by an HSD. These findings suggest that exogenous H₂S attenuates hypertension caused by an HSD by ameliorating oxidative stress, inflammation, and apoptosis in the PVN. This study provides evidence of the benefits of peripheral H₂S therapy for hypertension.

Protective effect of hydrogen sulfide against stress-induced lung injury: involvement of Nrf2, NFκB/iNOS, and HIF-1α signaling pathways

Stress is a common phenomenon that is attracting increasing attention. Hydrogen sulfide (H2S) is a gasotransmitter that plays an important role in many physiological and pathological events. Our study aimed to estimate the effect and the underlying mechanisms of the H2S donor, sodium hydrosulfide (NaHS), against immobilization stress (IS)-induced lung injury. Forty adult male rats were classified into control group, NaHS group, and IS groups with and without NaHS treatment. Serum was obtained to determine corticosterone (CORT), total antioxidant capacity (TAC), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) levels. Lung H2S, nitric oxide (NO), inducible nitric oxide synthase (iNOS), and malondialdehyde (MDA) levels were measured. Lung expressions of H2S synthesizing enzymes and Western blot analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) and hypoxia-inducible factor 1 alpha (HIF 1α) were estimated. Histopathological changes and immunohistochemical assessment of nuclear factor kappa B (NF-κB) and caspase-3 were also done. Pretreatment with NaHS led to marked histological protection from lung damage seen in IS rats. Furthermore, pretreatment with NaHS before IS protected lung H2S levels and expressions of H2S-synthesizing enzymes. Similarly, the levels of CORT, TNF-α, IL-10, MDA, TAC, NO, iNOS, HIF-1 α, and nuclear Nrf2 and expressions of NF-kB and caspase 3 were all maintained at near control levels in contrast to that in the IS rats. In conclusion, NaHS is protective against stress-induced lung injury due to its antioxidant, anti-inflammatory, anti-fibrotic, and antiapoptotic effects. Thus, NaHS can be used to minimize stress complications on lung.

Hydrogen Sulphide Treatment Prevents Renal Ischemia-Reperfusion Injury by Inhibiting the Expression of ICAM-1 and NF-kB Concentration in Normotensive and Hypertensive Rats

Our main objective was to investigate the effect of chronic administration of hydrogen sulphide donor (sodium hydrosulphide) on the expression of intercellular adhesion molecule-1 (ICAM-1) and concentration of nuclear factor-kappa B (NF-kB) in a renal ischemia-reperfusion injury (IRI) model of WKY and L-nitro-arginine-methyl-ester (L-NAME)-induced hypertensive rats. Sodium hydrosulphide (NaHS) was administered intraperitoneally (i.p.) for 35 days while cystathionine gamma lyase (CSE) inhibitor dL-propargylglycine (PAG) was administered at a single dose of 50 mg/kg. Animals were anesthetised using sodium pentobarbitone (60 mg/kg) and then prepared to induce renal ischemia by clamping the left renal artery for 30 min followed by 3 h of reperfusion. Pre-treatment with NaHS improved the renal functional parameters in both WKY and L-NAME-induced hypertensive rats along with reduction of blood pressure in hypertensive groups. Oxidative stress markers like malondialdehyde (MDA), total superoxide dismutase (T-SOD) and glutathione (GSH) were also improved by NaHS treatment following renal IRI. Levels of ICAM-1 and NF-kB concentration were reduced by chronic treatment with NaHS and increased by PAG administration after renal IRI in plasma and kidney. Treatment with NaHS improved tubular morphology and glomerulus hypertrophy. Pre-treatment with NaHS reduced the degree of renal IRI by potentiating its antioxidant and anti-inflammatory mechanism, as evidenced by decreased NF-kB concentration and downregulation of ICAM-1 expression.

Protective effect of hydrogen sulfide on the kidney (Review)

Hydrogen sulfide (H₂S) is a physiologically important gas transmitter that serves various biological functions in the body, in a manner similar to that of carbon monoxide and nitric oxide. Cystathionine-β-synthase, cystathionine-γ-lyase and cysteine transaminase/3-mercaptopyruvate sulphotransferase are important enzymes involved H₂S production in vivo, and the mitochondria are the primary sites of metabolism. It has been reported that H₂S serves an important physiological role in the kidney. Under disease conditions, such as ischemia-reperfusion injury, drug nephrotoxicity and diabetic nephropathy, H₂S serves an important role in both the occurrence and development of the disease. The present review aimed to summarize the production, metabolism and physiological functions of H₂S, and the progress in research with regards to its role in renal injury and renal fibrosis in recent years.

Research progress of hydrogen sulfide in Alzheimer's disease from laboratory to hospital: a narrative review

Alzheimer's disease is a neurodegenerative disease that mainly occurs in old age and early stages. Its main manifestations are memory impairment, aphasia, apraxia, loss of identity, abstract thinking and impairment of computing power, personality and behavior changes, etc. At present, the treatment of Alzheimer's disease only stays on reducing the disease and delaying the development, which is also a difficult problem to overcome in clinical practice. Hydrogen sulfide, as a third gaseous signal molecule after carbon monoxide and nitrogen monoxide, has become very popular in recent years. It shows very promising prospects in the Alzheimer's disease model. It can protect the nerve function and prevent the progress of the disease by affecting the amyloid precursor protein metabolism, anti-apoptosis, anti-inflammatory, and antioxidant pathways. Therefore, this article summarizes the relevant basic and clinical research of hydrogen sulfide in Alzheimer's disease, and discusses its progress and findings and mechanism characteristics.

Dapsone Ameliorates Isoproterenol-Induced Myocardial Infarction via Nrf2/ HO-1; TLR4/ TNF-α Signaling Pathways and the Suppression of Oxidative Stress, Inflammation, and Apoptosis in Rats

Myocardial infarction (MI) is a critical condition that can happen with high doses or rapid termination of beta blockers therapy. The study aimed to evaluate the potential anti-toxic value of DAP against isoproterenol (ISO) - induced MI. Twenty-eight male Wistar rats were used for the study. The rodents were assigned to four groups (n = 7) and the treatments were given for 12 days as follows; Group 1 (control): were administrated normal saline, Group 2 (DAP control): were administrated DAP (10 mg/kg/day IP), Group 3 (ISO group): were administrated ISO (100 mg/kg, IP on the 11th and 12th days of the experiment), and Group 4 (DAP + ISO): co-treated with DAP plus ISO. The measured parameters were cardiac malondialdehyde (MDA), reduced glutathione (GSH), total nitrite/nitrate (NOx), catalase (CAT), serum cardiac biomarkers; CK-MB, ALT, LDH, and ALK-PH. Also, interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase-1 (HO-1), toll-like receptor 4 (TLR4), caspase-3 activity, and hepatic BAX and Bcl-2 were also assessed. Also, histological examination and vimentin immuno-expressions were studied. ISO group exhibited MI as evidenced by the elevation in serum cardiac biomarkers, MDA, NOx, IL-1β, TNF-α, and caspase-3 together with the reduction in GSH, Nrf2, HO-1 levels, and a faint vimentin immuno-reaction. Histological alterations revealing distorted cardiomyocytes; vacuolation, edema, pyknosis, and fragmentation were also noticed. DAP significantly ameliorated all the examined toxicity indicators. DAP revealed efficient ameliorative actions against ISO-caused MI by marked reduction in myocardial infarct size and suppressed oxidative stress, inflammation, and apoptosis via the up-regulation of the Nrf2/HO-1; TLR4/TNF-α signaling pathways.

NaHS Alleviated Cell Apoptosis and Mitochondrial Dysfunction in Remote Lung Tissue after Renal Ischemia and Reperfusion via Nrf2 Activation-Mediated NLRP3 Pathway Inhibition

Objective

Acute kidney injury (AKI) is a common and severe complication in critically ill patients, often caused by renal ischemia-reperfusion (RIR). Previous studies have confirmed that lung injury, rather than renal injury, is one of the leading causes of AKI-induced death. The pathophysiological mechanisms of acute lung injury (ALI) resulting from AKI are very complex and remain unclear. In the present study, we aimed to explore the protective effects and potential mechanism of sodium hydrosulfide (NaHS) on lung injury in RIR mice.

Methods

The RIR model was established in wild-type and Nrf2^−/− mice. Different groups of mice were treated with NaHS and MCC950. Lung tissues were harvested to detect lung injury, mitochondrial function, cell apoptosis, the NLRP3 inflammasome, and Nrf2 pathway-related molecules.

Results

RIR led to a deterioration in lung histology, the wet/dry weight ratio, PaO₂/FiO₂, and mitochondrial function, in addition to stimulating the activation of the NLRP3 and Nrf2 pathways. MCC950 alleviated mitochondrial dysfunction, lung apoptosis, and histology injury in the lungs after RIR. NaHS treatment markedly improved the lung histological scores, the wet/dry weight ratio, bronchoalveolar lavage fluid (BALF) cell counts, BALF neutrophil counts, BALF neutrophil elastase activity, BALF protein concentration, PaO₂/FiO₂, mitochondrial morphology, the red/green fluorescence intensity that indicates changes in mitochondrial membrane potential, respiratory control rate (RCR), ATP, reactive oxygen species (ROS) release, and cell apoptosis via Nrf2-mediated NLRP3 pathway inhibition.

Conclusion

NaHS protected against RIR-induced lung injury, mitochondrial dysfunction, and inflammation, which is associated with Nrf2 activation-mediated NLRP3 pathway inhibition.

Expression of heme oxygenase-1 in type II pneumocytes protects against heatstroke-induced lung damage

Heatstroke (HS) is an acute clinical disease characterized by abnormal hyperthermia and multi-organ dysfunction. Heme oxygenase (HO)-1, also called heat shock protein (HSP)32, is induced by hyperthermia and also plays protective roles in many lung disease models. Based on this phenomenon, we investigated the protective role of endogenous HO-1 in heat-induced lung damage in rats. Male Sprague-Dawley (SD) rats were separated into three groups: (a) normothermic sham, (b) HS, and (c) SnPP (inhibitor of HO-1) pretreatment rats. In the HS group, rats were killed at various time points (1, 3, 6, and 12 h after heat exposure) in order to analyze messenger ribonucleic acid (mRNA) and protein levels. Lung sections were examined for tissue damage and localization of HO-1 using immunofluorescence double labeling. We found that HS induced lung pathology (congested and thickened lung septa). The level of HO-1 mRNA was increased at 1 h, and the protein level peaked at 6 h after heat exposure. Pretreatment with SnPP (tin-protoporphyrin IX, 30 mg/kg, intraperitoneal injection for 1 h before heat exposure) aggravated the lung damage. Furthermore, we demonstrated HO-1 expression in lung type II pneumocytes. Our results suggest that endogenous HO-1 is protective against HS-induced lung damage. Induction of HO-1 may be a potential therapeutic strategy for treating heat-related diseases.

Vitamin E protects against gabapentin-induced chronic hepatic and renal damage associated with the inhibition of apoptosis and tissue injury in rats

AIMS

This study aimed to investigate the potential protective effects of vitamin E against gabapentin-induced chronic liver and kidney injury associated with the inhibition of biomarkers of apoptosis and tissue injury.

MATERIALS AND METHODS

Four groups of adult male rats were included; control, gabapentin (100 mg/kg/day), Vitamin E (80 mg/kg/day), and a combination of gabapentin and Vitamin E for 90 days. Serum levels of AST, ALT, LDH, ALP, urea, and creatinine were measured in addition to malondialdehyde (MDA), and reduced glutathione (GSH) tissue levels. P53 gene expression, histological, and immunohistochemical examinations were performed in liver and kidney tissue samples.

KEY FINDINGS

Gabapentin increased AST, ALT, LDH, ALP, urea, creatinine, MDA, and p53 gene expression and it reduced GSH. Moreover, gabapentin administration caused structural changes in the hepatic and renal architecture with a weak Periodic acid-Schiff (PAS) reaction that reflects glycogen deposition in the liver and kidney and a positive immunoreaction for BCL2-associated X protein (BAX) that reflects activated apoptosis. Vitamin E significantly (p<0.05) reversed the biochemical alterations associated with chronic gabapentin administration and improved the histopathological picture of hepatic and renal tissue with a partial inhibition of BAX.

SIGNIFICANCE

Chronic administration of gabapentin causes hepatic and renal impairments, which is ameliorated by Vitamin E; possibly due to the inhibition of biomarkers of apoptosis and tissue injury.

Therapeutic Potential of Carbon Monoxide (CO) and Hydrogen Sulfide (H2S) in Hemolytic and Hemorrhagic Vascular Disorders-Interaction between the Heme Oxygenase and H2S-Producing Systems

Over the past decades, substantial work has established that hemoglobin oxidation and heme release play a pivotal role in hemolytic/hemorrhagic disorders. Recent reports have shown that oxidized hemoglobins, globin-derived peptides, and heme trigger diverse biological responses, such as toll-like receptor 4 activation with inflammatory response, reprogramming of cellular metabolism, differentiation, stress, and even death. Here, we discuss these cellular responses with particular focus on their mechanisms that are linked to the pathological consequences of hemorrhage and hemolysis. In recent years, endogenous gasotransmitters, such as carbon monoxide (CO) and hydrogen sulfide (H₂S), have gained a lot of interest in connection with various human pathologies. Thus, many CO and H₂S-releasing molecules have been developed and applied in various human disorders, including hemolytic and hemorrhagic diseases. Here, we discuss our current understanding of oxidized hemoglobin and heme-induced cell and tissue damage with particular focus on inflammation, cellular metabolism and differentiation, and endoplasmic reticulum stress in hemolytic/hemorrhagic human diseases, and the potential beneficial role of CO and H₂S in these pathologies. More detailed mechanistic insights into the complex pathology of hemolytic/hemorrhagic diseases through heme oxygenase-1/CO as well as H₂S pathways would reveal new therapeutic approaches that can be exploited for clinical benefit.

Hydrogen Sulfide and Carnosine: Modulation of Oxidative Stress and Inflammation in Kidney and Brain Axis

Emerging evidence indicates that the dysregulation of cellular redox homeostasis and chronic inflammatory processes are implicated in the pathogenesis of kidney and brain disorders. In this light, endogenous dipeptide carnosine (β-alanyl-L-histidine) and hydrogen sulfide (H₂S) exert cytoprotective actions through the modulation of redox-dependent resilience pathways during oxidative stress and inflammation. Several recent studies have elucidated a functional crosstalk occurring between kidney and the brain. The pathophysiological link of this crosstalk is represented by oxidative stress and inflammatory processes which contribute to the high prevalence of neuropsychiatric disorders, cognitive impairment, and dementia during the natural history of chronic kidney disease. Herein, we provide an overview of the main pathophysiological mechanisms related to high levels of pro-inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and neurotoxins, which play a critical role in the kidney–brain crosstalk. The present paper also explores the respective role of H₂S and carnosine in the modulation of oxidative stress and inflammation in the kidney–brain axis. It suggests that these activities are likely mediated, at least in part, via hormetic processes, involving Nrf2 (Nuclear factor-like 2), Hsp 70 (heat shock protein 70), SIRT-1 (Sirtuin-1), Trx (Thioredoxin), and the glutathione system. Metabolic interactions at the kidney and brain axis level operate in controlling and reducing oxidant-induced inflammatory damage and therefore, can be a promising potential therapeutic target to reduce the severity of renal and brain injuries in humans.

Evaluation of time passed since death by examination of oxidative stress markers, histopathological, and molecular changes of major organs in male albino rats

Recent biochemical, metabolic, and molecular profiles of various body fluids showed more accurate correlation to the postmortem interval than the traditional physical examination. Our study aimed to evaluate time passed since death in relation to oxidative stress markers, HMGB1 genetic expression, histopathological examination, and BCL2 immunohistochemical analysis in major organs (heart, kidney, and testis). Forty-two adult male rats were included and randomly divided into seven equal groups. After sacrification, the rodents were kept at room temperature and major organs were obtained at 0, 12, 24, 48, 72, 96, and 120 h. Malonaldehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH) tissue levels, High mobility group box 1 protein (HMGB1) gene expression, histopathological, and B cell lymphoma 2 (BCL2) immunohistochemical expressions were analyzed. Postmortem interval was correlated to different tissue levels of MDA, SOD, and GSH. HMGB1 showed enhanced postmortem gene expression with a peak at 48 h after death. Obvious time-dependent histopathological changes were observed in all the examined organs. Dilated spaces, extravasation, and fragmentation scores in heart specimens were higher at 96 and 120 h compared with the other groups. Renal changes in the form of shrunken glomeruli, loss of tubular epithelium, and hyalinization and testicular findings in the form of epithelial detachment, vacuolation, and loss of sperms started at 72 h postmortem. BCL2 expression began to decrease 24 h and became negative at 96 h after death. In conclusion, HMGB1 gene expression can be used for estimation of time passed since death as it shows time-dependent changes in the form of a progressive increase with a peak at 48 h then it begins to decline. Oxidants and antioxidants are correlated to PMI until 120 h after death. Histopathological changes in the heart, kidney, and testis are also time-dependent until the 5th day after death. BCL2 immunohistochemical expression begins to decline 24 h until 96 h after death when it becomes negative.

H2S- and NO-releasing gasotransmitter platform: A crosstalk signaling pathway in the treatment of acute kidney injury

Acute kidney injury (AKI) is a syndrome affecting most patients hospitalized due to kidney disease; it accounts for 15 % of patients hospitalized in intensive care units worldwide. AKI is mainly caused by ischemia and reperfusion (IR) injury, which temporarily obstructs the blood flow, increases inflammation processes and induces oxidative stress. AKI treatments available nowadays present notable disadvantages, mostly for patients with other comorbidities. Thus, it is important to investigate different approaches to help minimizing side effects such as the ones observed in patients subjected to the aforementioned treatments. Therefore, the aim of the current review is to highlight the potential of two endogenous gasotransmitters - hydrogen sulfide (H₂S) and nitric oxide (NO) - and their crosstalk in AKI treatment. Both H₂S and NO are endogenous signalling molecules involved in several physiological and pathophysiological processes, such as the ones taking place in the renal system. Overall, these molecules act by decreasing inflammation, controlling reactive oxygen species (ROS) concentrations, activating/inactivating pro-inflammatory cytokines, as well as promoting vasodilation and decreasing apoptosis, hypertrophy and autophagy. Since these gasotransmitters are found in gaseous state at environmental conditions, they can be directly applied by inhalation, or in combination with H₂S and NO donors, which are compounds capable of releasing these molecules at biological conditions, thus enabling higher stability and slow release of NO and H₂S. Moreover, the combination between these donor compounds and nanomaterials has the potential to enable targeted treatments, reduce side effects and increase the potential of H₂S and NO. Finally, it is essential highlighting challenges to, and perspectives in, pharmacological applications of H₂S and NO to treat AKI, mainly in combination with nanoparticulated delivery platforms.