Kidney Ischemia-Reperfusion Elicits Acute Liver Injury and Inflammatory Response

Role of cAMP/pCREB and GSK-3β/NF-κB p65 signaling pathways in the renoprotective effect of mirabegron against renal ischemia-reperfusion injury in rats

Acute kidney injury and other renal disorders are thought to be primarily caused by renal ischemia-reperfusion (RIR). Cyclic adenosine monophosphate (cAMP) has plenty of physiological pleiotropic effects and preserves tissue integrity and functions. This research aimed to examine the potential protective effects of the β3-adrenergic receptors agonist mirabegron in a rat model of RIR and its underlying mechanisms. Male rats enrolled in this work were given an oral dose of 30 mg/kg mirabegron for two days before surgical induction of RIR. Renal levels of kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), Interleukin-10 (IL-10), cAMP, cAMP-responsive element binding protein (pCREB), and glycogen synthase kinase-3 beta (GSK-3β) were assessed along with blood urea nitrogen and serum creatinine. Additionally, caspase-3 and nuclear factor-kappa B (NF-κB) p65 were explored by immunohistochemical analysis. Renal specimens were inspected for histopathological changes. RIR led to renal tissue damage with elevated blood urea nitrogen and serum creatinine levels. The renal KIM-1, MCP-1, TNF-α, and GSK-3β were significantly increased, while IL-10, cAMP, and pCREB levels were reduced. Moreover, upregulation of caspase-3 and NF-κB p65 protein expression was seen in RIR rats. Mirabegron significantly reduced kidney dysfunction, histological abnormalities, inflammation, and apoptosis in the rat renal tissues. Mechanistically, mirabegron mediated these effects via modulation of cAMP/pCREB and GSK-3β/NF-κB p65 signaling pathways. Mirabegron administration could protect renal tissue and maintain renal function against RIR.

pH-Activatable Pre-Nanozyme Mediated H2S Delivery for Endo-Exogenous Regulation of Oxidative Stress in Acute Kidney Injury

Oxidative stress induced by excess reactive oxygen species (ROS) is a primary pathogenic cause of acute kidney injury (AKI). Development of an effective antioxidation system to mitigate oxidative stress for alleviating AKI remains to be investigated. This study presents the synthesis of an ultra-small Platinum (Pt) sulfur cluster (Pt5.65S), which functions as a pH-activatable prefabricated nanozyme (pre-nanozyme). This pre-nanozyme releases hydrogen sulfide (H2S) and transforms into a nanozyme (Ptzyme) that mimics various antioxidant enzymes, including superoxide dismutase and catalase, within the inflammatory microenvironment. Notably, the Pt5.65S pre-nanozyme exhibits an endo-exogenous synergy-enhanced antioxidant therapeutic mechanism. The Ptzyme reduces oxidative damage and inflammation, while the released H2S gas promotes proneurogenesis by activating Nrf2 and upregulating the expression of antioxidant molecules and enzymes. Consequently, the Pt5.65S pre-nanozyme shows cytoprotective effects against ROS/reactive nitrogen species (RNS)-mediated damage at remarkably low doses, significantly improving treatment efficacy in mouse models of kidney ischemia-reperfusion injury and cisplatin-induced AKI. Based on these findings, the H2S-generating pre-nanozyme may represent a promising therapeutic strategy for mitigating inflammatory diseases such as AKI and others.

Impact of folic acid supplementation on ischemia‒reperfusion-induced kidney injury in rats: folic acid prophylactic role revisited

Folic acid (FA), with its anti-inflammatory and antioxidant properties, may offer protection against ischemia-reperfusion (IR) injury. This study investigated whether FA safeguards rat kidneys from IR by targeting high mobility group box-1 (HMGB1), a key inflammatory mediator. Fifty adult male Wistar rats were randomly allocated into four groups: control, IR, IR + FA pretreatment, and FA alone. Compared to controls, IR significantly impaired renal function and elevated levels of malondialdehyde, HMGB1, NF-κB, and caspase 3. FA pretreatment effectively reversed these detrimental changes, protecting renal function and minimizing tissue damage. The FA-alone group showed no significant differences compared to the control group, indicating no adverse effects of FA treatment. Mechanistically, FA inhibited HMGB1 expression and its downstream activation of NF-κB and caspase 3, thereby quelling inflammation and cell death. FA shields rat kidneys from IR-induced injury by suppressing HMGB1-mediated inflammation and apoptosis, suggesting a potential therapeutic avenue for IR-associated kidney damage.

Acute kidney injury comorbidity analysis based on international classification of diseases-10 codes

OBJECTIVE

Acute kidney injury (AKI) is a clinical syndrome that occurs as a result of a dramatic decline in kidney function caused by a variety of etiological factors. Its main biomarkers, serum creatinine and urine output, are not effective in diagnosing early AKI. For this reason, this study provides insight into this syndrome by exploring the comorbidities of AKI, which may facilitate the early diagnosis of AKI. In addition, organ crosstalk in AKI was systematically explored based on comorbidities to obtain clinically reliable results.

METHODS

We collected data from the Medical Information Mart for Intensive Care-IV database on patients aged [Formula: see text] 18 years in intensive care units (ICU) who were diagnosed with AKI using the criteria proposed by Kidney Disease: Improving Global Outcomes. The Apriori algorithm was used to mine association rules on the diagnoses of 55,486 AKI and non-AKI patients in the ICU. The comorbidities of AKI mined were validated through the Electronic Intensive Care Unit database, the Colombian Open Health Database, and medical literature, after which comorbidity results were visualized using a disease network. Finally, organ diseases were identified and classified from comorbidities to investigate renal crosstalk with other distant organs in AKI.

RESULTS

We found 579 AKI comorbidities, and the main ones were disorders of lipoprotein metabolism, essential hypertension, and disorders of fluid, electrolyte, and acid-base balance. Of the 579 comorbidities, 554 were verifiable and 25 were new and not previously reported. In addition, crosstalk between the kidneys and distant non-renal organs including the liver, heart, brain, lungs, and gut was observed in AKI with the strongest heart-kidney crosstalk, followed by lung-kidney crosstalk.

CONCLUSION

The comorbidities mined in this study using association rules are scientific and may be used for the early diagnosis of AKI and the construction of AKI predictive models. Furthermore, the organ crosstalk results obtained through comorbidities may provide supporting information for the management of short- and long-term treatment practices for organ dysfunction.

Cyclosporine A Does Not Mitigate Liver Ischemia/Reperfusion Injury in an Ex Vivo Porcine Model of Donation After Circulatory Death

BACKGROUND Ischemia/reperfusion injury (IRI) is an inherent problem in organ transplantation, owing to the obligate period of ischemia that organs must endure. Cyclosporine A (CsA), though better know as an immunosuppressant, has been shown to mitigate warm IRI in a variety of organ types, including the liver. However, there is little evidence for CsA in preventing hepatic IRI in the transplant setting. MATERIAL AND METHODS In the present study, we tested the effect of CsA on hepatic IRI in a large-animal ex vivo model of donation after circulatory death (DCD). Porcine donors were pre-treated with either normal saline control or 20 mg/kg of CsA. Animals were subject to either 45 or 60 minutes of warm ischemia before hepatectomy, followed by 2 or 4 hours of cold storage prior to reperfusion on an ex vivo circuit. Over the course of a 12-hour perfusion, perfusion parameters were recorded and perfusate samples and biopsies were taken at regular intervals. RESULTS Peak perfusate lactate dehydrogenase was significantly decreased in the lower-ischemia group treated with CsA compared to the untreated group (4220 U/L [3515-5815] vs 11 305 [10 100-11 674]; P=0.023). However, no difference was seen between controls and CsA-treated groups on other parameters in perfusate alanine or asparagine aminotransferase (P=0.912, 0.455, respectively). Correspondingly, we found no difference on midpoint histological injury score (P=0.271). CONCLUSIONS We found minimal evidence that CsA is protective against hepatic IRI in our DCD model.

The Effect of Sevoflurane and Fullerenol C 60 on the Liver and Kidney in Lower Extremity Ischemia-Reperfusion Injury in Mice with Streptozocin-Induced Diabetes

Objective

This study aimed to demonstrate whether fullerenol C60, sevoflurane anesthesia, or a combination of both had protective effects on the liver and kidneys in lower extremity ischemia-reperfusion injury (IRI) in mice with streptozocin-induced diabetes.

Methods

A total of 46 Swiss albino mice were divided into six groups as follows: control group (group C, n=7), diabetes group (group D, n=7), diabetes-ischemia/reperfusion (group DIR, n=8), diabetes-ischemia/reperfusion-fullerenol C60 (group DIR-FC60, n=8), diabetes-ischemia/reperfusion-sevoflurane (group DIR-S, n=8), and the diabetes-ischemia/reperfusion-fullerenol C60-sevoflurane (group DIR-S-FC60, n=8). Fullerenol C60 (100mg/kg) was administered intraperitoneally 30 min before the ischemia-reperfusion procedure to the fullerenol groups (DIR-FC60 and DIR-S-FC60). In the DIR groups, 2 hours (h) ischemia-2h reperfusion periods were performed. In the sevoflurane groups, sevoflurane was applied during the ischemia-reperfusion period with 100% O2. Liver and kidney tissues were removed at the end of the reperfusion procedure for biochemical and histopathological examinations.

Results

In liver tissue, hydropic degeneration, sinusoidal dilatation, pycnotic nuclei, prenecrotic cells, and mononuclear cell infiltration in parenchyma were significantly more frequent in group DIR than in groups D and group C. In terms of the histopathologic criteria examined, more positive results were seen in group DIR-FC60, and when group DIR-FC60 was compared with group DIR, the difference was significant. The best results in AST, ALT, glucose, TBARS levels, and SOD enzyme activities in liver tissue were in group DIR-FC60 compared with group DIR, followed by groups DIR-S-FC60 and DIR-S, respectively. Regarding TBARS levels and SOD enzyme activities in kidney tissue, the best results were in groups DIR-FC60, DIR-S-FC60, and DIR-S, respectively.

Conclusion

According to our findings, it is clear that fullerenol C60 administered intraperitoneally 30 min before ischemia, alone or together with sevoflurane, reduces oxidative stress in distant organ damage caused by lower extremity IRI, and reduces liver and kidney tissue damage in histopathologic examinations.

Alleviation of ischemia-reperfusion induced renal injury by chemically modified SOD2 mRNA delivered via lipid nanoparticles

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, which is a serious clinical condition with no effective pharmacological treatment. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) significantly alleviate kidney IRI; however, the underlying mechanisms and key molecules conferring renoprotection remain elusive. In this study, we characterized the protein composition of MSC-EVs using a proteomics approach and found that mitochondrial protein superoxide dismutase 2 (SOD2) was enriched in MSC-EVs. Using lipid nanoparticles (LNP), we successfully delivered chemically modified SOD2 mRNA into kidney cells and mice with kidney IRI. We demonstrated that SOD2 mRNA-LNP treatment decreased cellular reactive oxygen species (ROS) in cultured cells and ameliorated renal damage in IRI mice, as indicated by reduced levels of serum creatinine and restored tissue integrity compared with the control mRNA-LNP-injected group. Thus, the modulation of mitochondrial ROS levels through SOD2 upregulation by SOD2 mRNA-LNP delivery could be a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Cardamonin mitigates kidney injury by modulating inflammation, oxidative stress, and apoptotic signaling in rats subjected to renal ischemia and reperfusion

Renal ischemia-reperfusion injury (IRI) is a critical health concern that aggravates the pathophysiology of acute kidney injury (AKI), leading to high mortality rates in intensive care units. Cardamonin is a natural compound with anti-inflammatory and antioxidant properties. The current study aimed to evaluate the renoprotective impact of cardamonin against AKI induced by renal IRI. Male rats (n=5 per group) were divided into four groups: the sham group underwent anesthesia and abdominal incision only; the control group experienced bilateral renal artery clamping for 30 minutes followed by 2 hours of reperfusion; the vehicle group received the cardamonin vehicle 30 minutes before ischemia induction; and the cardamonin group was administered 5 mg/kg of cardamonin 30 minutes before ischemia. Blood urea nitrogen (BUN) and creatinine were measured to assess the renal function. Tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin-6 (IL-6), caspase 3, and F2-isoprostane were assessed in renal tissues. Kidney injury was examined using the hematoxylin and eosin stain method. Compared to the sham group, the control group exhibited significantly higher levels of BUN, creatinine, TNF-α, IL-1β, IL-6, F2-isoprostane, and caspase 3 in renal tissues, along with severe kidney injury as evidenced by histological analysis. Compared to the control group, pretreatment with cardamonin resulted in a significant reduction in these biomarkers and alleviated renal damage. Cardamonin had renoprotective effects against renal ischemia and reperfusion injury via modulating inflammation, oxidative stress, and apoptosis pathways.

Clinical factors distinguishing renal infarction from acute pyelonephritis: A randomly matched retrospective case-control study

INTRODUCTION

Renal infarction (RI) is rare but clinically important because the appropriate treatment depends on the time of diagnosis. RI is often misdiagnosed as acute pyelonephritis (APN) because both diseases have nonspecific symptoms such as flank pain and abdominal pain. We identified predictors for distinguishing RI from APN.

METHODS

The data of patients visited the emergency department and diagnosed with RI or APN from March 2016 to May 2020 were prospectively collected and retrospectively analyzed. Patients aged under 18 years, with a history of trauma, or incomplete medical records were excluded. Using a matching ratio of 1:5, RI patients were randomly matched to APN patients. Multivariable logistic regression analysis was performed to identify factors that could distinguish RI from APN. In addition, we constructed a decision tree to identify patterns of risk factors and develop prediction algorithms.

RESULTS

The RI and APN groups included 55 and 275 patients, respectively. Multivariable logistic regression analysis showed that male sex (OR, 6.161; p = 0.009), atrial fibrillation (AF) (OR, 14.303; p = 0.021), costovertebral angle tenderness (CVAT) (OR, 0.106; p < 0.001), aspartate transaminase (AST) level > 21.50 U/L (OR, 19.820; p < 0.001), C-reactive protein (CRP) level < 19.75 mg/L (OR, 10.167; p < 0.001), and pyuria (OR, 0.037; p < 0.001) were significantly associated with RI distinguishing from APN.

CONCLUSION

Male sex, AF, no CVAT, AST level > 21.50 U/L, CRP level < 19.75 mg/L, and no pyuria were significant factors that could distinguish RI from APN.

Protective Effect of Peptide Calcium Channel Blocker Omega-Hexatoxin-Hv1a on Epithelial Cell during Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) is a common phenomenon that develops both from natural causes and during major operations. Many intracellular processes mediated by calcium ions are involved in the development of IRI. Currently, chemical calcium channel blockers are used but they have a number of limitations. In this article, we study the effect of the omega-hexatoxin-Hv1a peptide toxin, an alternative to chemical calcium channel blockers, on the mechanisms of IRI development in epithelial cell culture. The toxin was produced using solid phase peptide synthesis. IRI was caused by deprivation of glucose, serum and oxygen. The data obtained demonstrate that the omega-hexatoxin-Hv1a toxin in nanomolar concentrations is able to prevent the development of apoptosis and necrosis in epithelial cells by reducing the concentration of calcium, sodium and potassium ions, as well as by delaying rapid normalization of the pH level, affecting the mitochondrial potential and oxidative stress. This toxin can be used as an alternative to chemical calcium channel blockers for preventing tissue and organ IRI due to its low-dose requirement and high bioavailability.

Role of Iberin as an anti-apoptotic agent on renal ischemia-reperfusion injury in rats

Ischemia-reperfusion injury (IRI) is a major contributor to acute and chronic kidney failure, heart failure, and ischemic stroke. This study aimed to investigate the therapeutic potential of Iberin, known for its anti-inflammatory, antioxidant, and antiapoptotic properties, in a rat model of renal IRI. Twenty-four adult male rats were randomly divided into four groups: Group I (Sham group) underwent laparotomy without IRI induction; Group II (Control group) underwent laparotomy followed by renal artery clamping for 30 minutes to induce ischemia, followed by 2 hours of reperfusion; Group III (Iberin treatment group) received a pre-injection of Iberin (15 mg/kg) and underwent 30 minutes of ischemia followed by 2 hours of reperfusion; and Group IV (Vehicle-treated group) received the vehicle (ethanol) 1 hour prior to ischemia and reperfusion induction. Iberin was diluted with ethanol. Biomarkers associated with inflammation, oxidative stress, and apoptosis were measured using enzyme-linked immunosorbent assay. Iberin treatment significantly reduced levels of inflammatory cytokines interleukin-1β (IL-1β) and IL-6, Bcl-2-associated X protein (BAX), tumor necrosis factor α (TNF-α), nuclear factor kappa p56, high mobility group B1, and neutrophil gelatinase-associated lipocalin. Moreover, Iberin increased levels of heat shock protein and Bcl2 compared to the control and vehicle groups. Iberin treatment prolonged the ischemic tolerance of renal tissue, potentially preventing or delaying irreversible injuries. These findings highlight the potential of Iberin as a promising candidate for mitigating renal injury caused by ischemia-reperfusion, due to its ability to modulate inflammatory markers.

Reno- and hepato-protective effect of allopurinol after renal ischemia/reperfusion injury: Crosstalk between xanthine oxidase and peroxisome proliferator-activated receptor gamma signaling

Renal ischemia/reperfusion (I/R) is a common cause of acute kidney injury and remote liver damage is an ultimate negative outcome. Current treatments for I/R typically involve the use of antioxidants and anti-inflammatory to protect against oxidative stress and inflammation. Xanthine oxidase (XO) and PPAR-γ contribute to renal I/R-induced oxidative stress; however, the crosstalk between the two pathways remains unexplored. In the present study, we report that XO inhibitor, allopurinol (ALP), protects kidney and liver after renal I/R by PPAR-γ activation. Rats with renal I/R showed reduced kidney and liver functions, increased XO, and decreased PPAR-γ. ALP increased PPAR-γ expression and improved liver and kidney functions. ALP also reduced inflammation and nitrosative stress indicated by reduction in TNF-α, iNOS, nitric oxide (NO), and peroxynitrite formation. Interestingly, rats co-treated with PPAR-γ inhibitor, BADGE, and ALP showed diminished beneficial effect on renal and kidney functions, inflammation, and nitrosative stress. This data suggests that downregulation of PPAR-γ contributes to nitrosative stress and inflammation in renal I/R and the use of ALP reverses this effect by increasing PPAR-γ expression. In conclusion, this study highlights the potential therapeutic value of ALP and suggests targeting XO-PPAR-γ pathway as a promising strategy for preventing I/R injury.

Acute kidney injury and distant organ dysfunction-network system analysis

Acute kidney injury (AKI) occurs in about half of critically ill patients and associates with high in-hospital mortality, increased long-term mortality post-discharge and subsequent progression to chronic kidney disease. Numerous clinical studies have shown that AKI is often complicated by dysfunction of distant organs, which is a cause of the high mortality associated with AKI. Experimental studies have elucidated many mechanisms of AKI-induced distant organ injury, which include inflammatory cytokines, oxidative stress and immune responses. This review will provide an update on evidence of organ crosstalk and potential therapeutics for AKI-induced organ injuries, and present the new concept of a systemic organ network to balance homeostasis and inflammation that goes beyond kidney-crosstalk with a single distant organ.

Acute Kidney Injury Induces Oxidative Stress and Hepatic Lipid Accumulation through AMPK Signaling Pathway

Acute kidney injury (AKI) often impairs the function of other organs leading to distant organ injury. The liver is the major organ that regulates metabolism and lipid homeostasis in the body. It has been reported that AKI causes liver injury with increased oxidative stress, inflammatory response and steatosis. In the present study, we investigated the mechanisms by which ischemia-reperfusion-induced AKI caused hepatic lipid accumulation. Kidney ischemia (45 min)-reperfusion (24 h) led to a significant increase in plasma creatinine and transaminase in Sprague Dawley rats, indicating kidney and liver injury. Histological and biochemical analyses revealed hepatic lipid accumulation with a significant elevation of triglyceride and cholesterol levels in the liver. This was accompanied by a decreased AMP-activated protein kinase (AMPK) phosphorylation, indicating the reduced activation of AMPK, which is an energy sensor that regulates lipid metabolism. The expression of AMPK-regulated genes that were responsible for fatty acid oxidation (CPTIα, ACOX) was significantly decreased, while the expression of lipogenesis genes (SREPB-1c, ACC1) was significantly elevated. The oxidative stress biomarker malondialdehyde was elevated in the plasma and liver. Incubation of HepG2 cells with an oxidative stress inducer hydrogen peroxide inhibited AMPK phosphorylation and caused cellular lipid accumulation. This was accompanied by decreased expression of genes responsible for fatty acid oxidation and increased expression of genes responsible for lipogenesis. These results suggest that AKI elicits hepatic lipid accumulation through decreased fatty acid metabolism and increased lipogenesis. Oxidative stress may contribute, in part, to the downregulation of the AMPK signaling pathway leading to hepatic lipid accumulation and injury.

Effects of Coriandrum sativum on distant organ inflammation and apoptosis due to liver ischemia/reperfusion injury

Liver ischemia/reperfusion (IR) often affects distant organs, such as small intestine, kidney, and lung. Coriandrum sativum (CS) has an antioxidant and anti-inflammatory effect on liver damage. The aim of this study was to investigate the anti-inflammatory and antiapoptotic effects of CS extract on small intestine, lung, and kidney after the liver IR injury. Small intestine, lung, and kidney tissues were evaluated and scored in terms of cell degeneration, inflammation, and congestion, as well as caspase-3 (Cas-3) and cluster of differentiation 31 (CD31) immunostainings were carried out. Renal enzymes, creatinine and urea levels were measured biochemically in serum. After IR, a decrease in villi size, diffuse degeneration, epithelial cell shedding and extensive congestion in the capillaries were observed. Meanwhile, the number of degenerated villi and congestion decreased in the IR+CS group. Due to IR, increased congestion was detected in the interalveolar septum of the lungs and in the capillaries between the kidney tubules. It was also observed that the positively stained cells with Cas-3 and CD31 were increased in the lung, kidney, and small intestine tissues of the IR group, and decreased in the IR+CS group. Kidney enzymes, urea and creatinine levels were significantly increased in the IR group and decreased in the IR+CS group. In conclusion, it was observed that liver IR caused changes in distant organs, especially in the small intestine, lung, and kidneys. Damaging effects of IR as well as apoptosis and inflammation were found to be decreased in the groups treated with CS.

Combined saline and vildagliptin induced M2 macrophage polarization in hepatic injury induced by acute kidney injury

Acute kidney injury (AKI) is a prevalent medical condition accompanied by mutual affection of other organs, including the liver resulting in complicated multiorgan malfunction. Macrophages play a vital role during tissue injury and healing; they are categorized into "classically activated macrophages" (M1) and "alternatively activated macrophages" (M2). The present study investigated and compared the conventional fluid therapy vs Dipeptidyl peptidase 4 inhibitor (DPP-4i) vildagliptin on the liver injury induced by AKI and evaluated the possible molecular mechanisms. Thirty rats comprised five groups (n = 6 rats/group): control, AKI, AKI+saline (received 1.5 mL of normal saline subcutaneous injection), AKI+vildagliptin (treated with oral vildagliptin 10 mg/kg), AKI+saline+vildagliptin. AKI was induced by intramuscular (i.m) injection of 50% glycerol (5 ml/kg). At the end of the work, we collected serum and liver samples for measurements of serum creatinine, blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrotic factor-α (TNF-α), and interleukin-10 (IL-10). Liver samples were processed for assessment of inducible nitric oxide synthase (iNOS) as a marker for M1, arginase 1 (Arg-1) as an M2 marker, c-fos, c-Jun, mitogen-activated protein kinase (MAPK), activator protein 1 (AP-1), and high-mobility-group-box1 (HMGB1) protein. The difference was insignificant regarding the relative expression of AP-1, c-Jun, c-fos, MAPK, and HMGB between the AKI+saline group and the AKI+Vildagliptin group. The difference between the same two groups concerning the hepatic content of the M1 marker (iNOS) and the M2 marker Arg-1 was insignificant. However, combined therapy produced more pronounced changes in these markers, as the difference in their relative expression between the AKI+saline+Vildagliptin group and both the AKI+saline group and the AKI+Vildagliptin group was significant. Accordingly, we suggest that the combined saline and vildagliptin hepatoprotective effect involves the downregulation of the MAPK/AP-1 signaling pathway.

PROTECTIVE EFFECT OF EPROSARTAN IN RENAL ISCHEMIA REPERFUSION INJURY BY REGULATING OXIDATIVE STRESS, INFLAMMATION, AND APOPTOTIC CASCADES IN A BILATERAL RAT MODEL

OBJECTIVE

The aim: To evaluate the potential protective effect of Eprosartan (ARB) in bilateral renal IRI in male rats.

PATIENTS AND METHODS

Materials and methods: 20 Sprague-Dawley rats divided into four groups. Sham group had surgery without IRI. Control group was subjected to 30 min ischemia and 2 hours of reperfusion. Vehicle group received 14 ml/kg (IP) injection of solvent mixture containing (10% DMSO, 40% PEG300, 5% Tween-80, and 45% normal saline) 30 minutes before clamping. Eprosartan-treated group with 30 mg/kg Eprosartan intraperitoneally 30 min before occlusion of renal pedicles followed by 30 minutes of ischemia and 2 hours of reperfusion. Serum BUN and Creatinine used to assess renal function. Renal tissue was used to measure the levels of TNF-α, IL-1β, IL-6, F2-isoprostane, and Caspase3 were measured by assessment of renal tissue. Histopathological examinations were conducted to detect parenchymal damage.

RESULTS

Results: Mean serum levels of BUN and Creatinine as well as mean renal tissue levels of TNF-α, IL-1β, IL-6, F2-isoprostane, and Caspase3 were significantly increased in control and vehicle groups together with increase in histological damage score compared to sham group, whereas treatment of rats with Eprosartan resulted in significant reduction in mean serum levels of BUN and Creatinine and mean renal tissue levels of TNF-α, IL-1β, IL-6, F2-isoprostane, and Caspase3 and obvious reduction in tissue injury.

CONCLUSION

Conclusions: This study demonstrates that Eprosartan pretreatment enhances kidney function by decreasing serum BUN and Creatinine, oxidative stress, cytokines, and apoptotic markers.

The Effect of Thyme Essential Oil on Liver Injuries Caused by Renal Ischemia-Reperfusion in Rats

Liver damage occurs following renal ischemia-reperfusion (RIR) that can cause inflammation and inflammatory cytokines activated after kidney injury. In this study, thyme essential oil (TE) with antioxidant and anti-inflammatory properties was used to reduce liver damage induced by renal IR. 32 male rats were randomly divided into 4 equal groups: (1) control, (2) RIR, (3) RIR+TE, and (4) TE. Rats received TE as a pretreatment at a dose of 0.5 ml/kg for one week. Then, under anesthesia for 45 minutes for ischemia, the kidneys of the animals were closed with clamps, and reperfusion was performed for 24 hours. Animal serum was isolated to evaluate alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) parameters. The liver of rats was examined for the measurement of malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), glutathione peroxidase (GPX), catalase (CAT), and expression of genes such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and caspase-3. ALP, AST, ALT, MDA, NO, IL-6, TNF-α, and caspase-3 increased significantly in the RIR group compared to the control group (p < 0.05). GSH, GPX, and CAT decreased significantly in the RIR group compared to the control group (p < 0.05). TE caused a decrease in ALP, AST, ALT, MDA, NO, IL-6, and TNF-α compared to the RIR group and caused an increase in the amount of GSH, GPX, and CAT in the RIR group (p < 0.05). This study showed that TE has antioxidant and anti-inflammatory properties that reduce liver damage induced by RIR.

Meprin β expression modulates the interleukin-6 mediated JAK2-STAT3 signaling pathway in ischemia/reperfusion-induced kidney injury

Meprin metalloproteinases have been implicated in the pathophysiology of ischemia/reperfusion (IR)-induced kidney injury. Previous in vitro data showed that meprin β proteolytically processes interleukin-6 (IL-6) resulting in its inactivation. Recently, meprin-β was also shown to cleave the IL-6 receptor. The goal of this study was to determine how meprin β expression impacts IL-6 and downstream modulators of the JAK2-STAT3-mediated signaling pathway in IR-induced kidney injury. IR was induced in 12-week-old male wild-type (WT) and meprin β knockout (βKO) mice and kidneys obtained at 24 h post-IR. Real-time PCR, western blot, and immunostaining/microscopy approaches were used to quantify mRNA and protein levels respectively, and immunofluorescence counterstaining with proximal tubule (PT) markers to determine protein localization. The mRNA levels for IL-6, CASP3 and BCL-2 increased significantly in both genotypes. Interestingly, western blot data showed increases in protein levels for IL-6, CASP3, and BCL-2 in the βKO but not in WT kidneys. However, immunohistochemical data showed increases in IL-6, CASP3, and BCL-2 proteins in select kidney tubules in both genotypes, shown to be PTs by immunofluorescence counterstaining. IR-induced increases in p-STAT-3 and p-JAK-2 in βKO at a global level but immunoflourescence counterstaining demonstrated p-JAK2 and p-STAT3 increases in select PT for both genotypes. BCL-2 increased only in the renal corpuscle of WT kidneys, suggesting a role for meprins expressed in leukocytes. Immunohistochemical analysis confirmed higher levels of leukocyte infiltration in WT kidneys when compared to βKO kidneys. The present data demonstrate that meprin β modulates IR-induced kidney injury in part via IL-6/JAK2/STAT3-mediated signaling.

Mortality and costs associated with acute kidney injury following major elective, non-cardiac surgery

OBJECTIVE

This study evaluated postoperative AKI severity and its relation to short- and long-term patient outcomes.

DESIGN

A retrospective, single-center cohort study of patients undergoing surgery from January 2015 to May 2020.

SETTING

An urban, academic medical center.

PATIENTS

Adult patients undergoing elective, non-cardiac surgery at our institution with a postoperative length of stay (LOS) of at least 24 h were included. Patients were included in 1-year mortality analysis if their procedure occurred prior to June 2019.

INTERVENTIONS

None.

MEASUREMENTS

Postoperative AKI was identified and staged using the Kidney Disease Improving Global Outcomes definitions. The outcomes analyzed were in-hospital mortality, LOS, total cost of the surgical hospitalization, and 1-year mortality.

MAIN RESULTS

Of the 8887 patients studied, 648 (7.3%) had postoperative AKI. AKI was associated with severity-dependent increases in all outcomes studied. Patients with AKI had rates of in-hospital mortality of 2.0%, 3.8%, and 12.5% for stage 1, 2, and 3 AKI compared to 0.3% for patients without AKI. Mean total costs of the surgical hospitalization were $23,896 (SD $23,736) for patients without AKI compared to $33,042 (SD $27,115), $39,133 (SD $34,006), and $73,216 ($82,290) for patients with stage 1, 2, and 3 AKI, respectively. In the 6729 patients who met inclusion for 1-year mortality analysis, AKI was also associated with 1-year mortality rates of 13.9%, 19.4%, and 22.7% compared to 5.2% for patients without AKI. In multivariate models, stage 1 AKI patients still had a higher probability of 1-year mortality (OR 1.9, 95% CI 1.3-2.6, p < 0.001) in addition to $4391 of additional costs when compared to patients without AKI (95% CI $2498-$6285, p < 0.001).

CONCLUSIONS

All stages of postoperative AKI were associated with increased LOS, surgical hospitalization costs, in-hospital mortality, and 1-year mortality. These findings suggest that patients with even a low-grade or stage 1 AKI are at higher risk for short- and long-term complications.

Possible Underlying Mechanisms for the Renoprotective Effect of Retinoic Acid-Pretreated Wharton's Jelly Mesenchymal Stem Cells against Renal Ischemia/Reperfusion Injury

Objectives: The current work investigated the effect of Wharton jelly mesenchymal stem cells (WJ-MSCs) pretreated with all-trans-retinoic acid (ATRA) on renal ischemia in rats and the possible role of oxidative stress, apoptotic and Wnt/β-Catenin signaling pathways, and inflammatory cytokines in their effects. Methods: The study included 90 male Sprague Dawley rats that were allocated to five groups (n = 18 rats): (I) Sham-operated group (right nephrectomy was performed); (II) Ischemia/reperfusion injury (IRI) group, a sham group with 45-min renal ischemia on the left kidney; (III) ATRA group, an ischemic group with an intravenous (i.v.) administration of ATRA 10 µM, 10 min post-surgery); (IV) WJ-MSCs group, an IRI group with an i.v. administration of 150 µL containing 7 × 106 WJ-MSCs, 10 min post-surgery; (V) WJ-MSCs + ATRA group, an IRI group with an i.v. administration of 150 µL of 7 × 106 WJ-MSCs pretreated with 10 µM ATRA. At the end of the experiments, serum creatinine, BUN micro-albuminuria (MAU), urinary protein, markers of redox state in the left kidney (MDA, CAT, SOD, and GSH), and the expression of Bax, IL-6, HIF-1α, Wnt7B, and β-catenin genes at the level of mRNA as well as for immunohistochemistry for NFkB and β-Catenin markers were analyzed. Results: The current study found that 45-min of renal ischemia resulted in significant impairment of kidney function (evidenced by the increase in serum creatinine, BUN, and urinary proteins) and deterioration of the kidney morphology, which was associated with a significant increase in redox state (evidenced by an increase in MDA and a decrease in GSH, SOD, and CAT), and a significant increase in inflammatory and apoptotic processes (evidenced by an increase in Bax and IL-6, NFkB, Wnt7B, β-catenin and HIF-1α) in kidney tissues (p < 0.05). On the other hand, treatment with ATRA, WJ-MSCs, or a combination of both, caused significant improvement in kidney function and morphology, which was associated with significant attenuation of oxidative stress, apoptotic markers, and inflammatory cytokines (IL6 and NFkB) with the upregulation of HIF-1α and β-catenin in kidney tissues (p < 0.05). Moreover, the renoprotective effect of WJ-MSCs pretreated with ATRA was more potent than WJ-MSCs alone. Conclusions: It is concluded that preconditioning of WJ-MSCs with ATRA may enhance their renoprotective effect. This effect could be due to the upregulation of the beta-catenin/Wnt pathway and attenuation of apoptosis, inflammation, and oxidative stress.

Association of FIB-4 index and clinical outcomes in critically ill patients with acute kidney injury: a cohort study

Background

The relationship between fibrosis-4 (FIB-4) index and clinical outcomes in patients with acute kidney injury (AKI) is unclear. We aimed to investigate the association between FIB-4 index and all-cause mortality in critically ill patients with AKI.

Methods

We used data from the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC-III) database (v1.4). The FIB-4 score was calculated using the existing formulas. logistic regression model, and Cox proportional hazards model were used to assessed the relationship between the FIB-4 index and in-hospital,28-day and 90-day mortality, respectively.

Results

A total of 3592 patients with AKI included in the data analysis. 395 (10.99%) patients died during hospitalization and 458 (12.74%) patients died in 28-day. During the 90-day follow-up, 893 (22.54%) patients were dead. An elevated FIB-4 value was significantly associated with increased in-hospital mortality when used as a continuous variable (odds ratio [OR] 1.183, 95% confidence interval [CI] 1.072–1.305, P = 0.002) and as a quartile variable (OR of Q2 to Q4 1.216–1.744, with Q1 as reference). FIB-4 was positively associated with 28-day mortality of AKI patients with hazard ratio (HR) of 1.097 (95% CI 1.008, 1.194) and 1.098 (95% 1.032, 1.167) for 90-day mortality, respectively.

Conclusion

This study demonstrated the FIB-4 index is associated with clinical outcomes in critically ill patients with acute kidney injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02071-2.

Remote liver injury following acute renal ischaemia-reperfusion: involvement of circulating exosomal miR-687 and regulation by thymoquinone

NEW FINDINGS

What is the central question of this study? What is the role of circulating exosomal miR-687 in remote hepatic injury following renal ischaemia-reperfusion injury (IRI) and does thymoquinone have a modulatory impact? What is the main finding and its importance? Exosomal miR-687 was expressed in renal IRI, entered the circulation and was deposited in the liver. Liver exosomal miR-687 was correlated with liver inflammation and apoptosis. Thymoquinone aborted the renal production of exosomal miR-687 and its further circulation to the liver.

ABSTRACT

The pathophysiology of remote hepatic injury following acute renal ischaemia-reperfusion injury (IRI) is of particular clinical interest. Secreted small non-coding microRNA (miRs) are thought to exist in exosome-encapsulated form. Thymoquinone (TQ) is the main bioactive ingredient of Nigella sativa and has several renoprotective actions. We expected exosomal miR-687 to be relevant as it could act as a humoral mediator, with possible modulation by TQ. Thirty adult male Wister albino rats were assigned to three groups (n = 10); (1) sham-operated, (2) renal ischaemia-reperfusion injury (IRI), and (3) renal IRI pre-treated with TQ 10 mg/kg/day i.v. (TQ-IRI) for 10 days in addition to a dose administered at reperfusion onset. Following 24 h of reperfusion, the IRI group showed renal tissue hypoxia-inducible factor upregulation (P < 0.001). Electron microscopy images of exosomes and analysis of miR-687 revealed elevated levels, which appeared in the circulation. Large amounts of exosomal miR-687 were transmitted to the liver tissue. In the IRI group, liver transaminases (alanine aminotransferase, aspartate aminotransferase) were markedly (P < 0.001) elevated. The hepatic tissue inflammatory markers (vascular cell adhesion molecule-1, myeloperoxidase, monocyte chemotactic protein-1 and nuclear factor-κB) were upregulated (P < 0.001) accompanied with elevated caspase-3. TQ suppressed (P < 0.001) the renal expression and release of exosomal miR-687 into the circulation and its further deposition in the liver tissue; consequently, TQ diminished (P < 0.001) liver tissue inflammation and cellular apoptosis. The results were confirmed by histological tissue assessment. In conclusion, exosomal miR-687 liberated from injured renal tissues into the circulation may be an important factor in inducing remote hepatic injury. Exosomal miR-687 inhibition by TQ protected both renal and hepatic tissues from injury.

Kidney Ischemia-Reperfusion Decreases Hydrogen Sulfide and Increases Oxidative Stress in the Heart

Patients with acute kidney injury (AKI) have an increased risk of cardiovascular disease. The underlying mechanism of AKI-induced heart injury is not well-understood. Hydrogen sulfide (H₂S), at physiological concentrations, has been implicated in cardiovascular protection through redox balance and vessel relaxation. Cystathionine gamma-lyase (CSE) plays an essential role in H₂S production in the heart. The present study investigated the effect of AKI on H₂S production and oxidative stress in the heart. AKI was induced by kidney ischemia-reperfusion in male and female Sprague-Dawley rats, which led to an increase in plasma creatinine and blood urea nitrogen levels. There was a significant increase in lipid peroxidation and a decrease in glutathione (antioxidant) levels in the plasma and heart, indicating systemic and cardiac oxidative stress. Kidney ischemia-reperfusion reduced CSE expression and H₂S production in the heart. There was a decrease in antioxidant transcription factor Nrf2 level in the nucleus and an increase in inflammatory cytokine (IL-6, TNF-α) expression in the heart. These results suggest that AKI can down-regulate CSE-mediated H₂S production, reduce glutathione levels and increase oxidative stress in the heart. This may contribute to an increased risk of cardiovascular disease in AKI.

Acute Kidney Injury and Pediatric Bone Health

Acute kidney injury (AKI) has been associated with deleterious impacts on a variety of body systems. While AKI is often accompanied by dysregulation of mineral metabolism-including alterations in calcium, phosphate, vitamin D, parathyroid hormone, fibroblast growth factor 23, and klotho-its direct effects on the skeletal system of children and adolescents remain largely unexplored. In this review, the pathophysiology of dysregulated mineral metabolism in AKI and its potential effects on skeletal health are discussed, including data associating AKI with fracture risk.