Protective Effects of Simvastatin on Endotoxin-Induced Acute Kidney Injury through Activation of Tubular Epithelial Cells' Survival and Hindering Cytochrome C-Mediated Apoptosis

Renal tubular epithelial cells response to injury in acute kidney injury

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid and significant decrease in renal function that can arise from various etiologies, and is associated with high morbidity and mortality. The renal tubular epithelial cells (TECs) represent the central cell type affected by AKI, and their notable regenerative capacity is critical for the recovery of renal function in afflicted patients. The adaptive repair process initiated by surviving TECs following mild AKI facilitates full renal recovery. Conversely, when injury is severe or persistent, it allows the TECs to undergo pathological responses, abnormal adaptive repair and phenotypic transformation, which will lead to the development of renal fibrosis. Given the implications of TECs fate after injury in renal outcomes, a deeper understanding of these mechanisms is necessary to identify promising therapeutic targets and biomarkers of the repair process in the human kidney.

MicroR-380-3p Reduces Sepsis-Induced Acute Kidney Injury via Regulating RAB1P to Restrain NF-κB Pathway

Septic acute kidney injury (AKI) is a common complication in critically ill patients with high morbidity and mortality. This study intends to clarify the clinical value and molecular mechanism of microR-380-3p in septic AKI by recruiting patients with septic AKI and establishing septic AKI cell models. Patients with septic AKI were included and human kidney-2 (HK-2) cells were induced by lipopolysaccharide (LPS) to construct the AKI cell model of sepsis. The expression of microR-380-3p was detected by quantitative real-time RT-PCR (qRT-PCR). The expression of Bax, cleaved caspase 3, Bcl-2, p65, and p-p65 was detected by Western blot. The contents of inflammation and oxidation were determined by commercial kits. Bioinformatics predicted the binding target of microR-380-3p and a dual luciferase reporting system was used to verify the regulatory relationship between microR-380-3p and RAP1B. The concentration of microR-380-3p was elevated in patients with septic AKI and appeared to be a biomarker for these patients. Silenced microR-380-3p reversed the damage of LPS on HK-2 cells via promoting viability, inhibiting apoptosis, inflammation, and oxidation. RAP1B was a target of microR-380-3p and microR-380-3p exerted targeted inhibition of RAP1B expression level. Down-regulation of RAP1B reversed the influence of silenced microR-380-3p on HK-2 cells. MicroR-380-3p/RAP1B participated in activating the NF-κB pathway. MicroR-380-3p down-regulated RAP1B to exacerbate septic AKI, providing a potential therapeutic biomarker for septic AKI.

Liraglutide Protects Cardiomyocytes against Isoprenaline-Induced Apoptosis in Experimental Takotsubo Syndrome

Takotsubo syndrome (TTS) is a stress-induced cardiomyopathy, characterized by an increased concentration of catecholamines, free radicals, and inflammatory cytokines, endothelial dysfunction, and increased apoptotic activity. High doses of isoprenaline are used in animal models to induce Takotsubo (TT)-like myocardial injury. The aim of the study was to investigate the antiapoptotic effects of liraglutide in experimental TTS and its role in the NF-κB pathway. Wistar rats were pretreated with liraglutide for 10 days, and on days 9 and 10, TT-like myocardial injury was induced with isoprenaline. After the sacrifice on day 11, hearts were isolated for histopathological and immunohistochemical analysis. Liraglutide reduced isoprenaline-induced cardiomyocyte apoptosis by decreasing cleaved caspase-3 (CC3), BCL-2-associated X protein (BAX), and NF-κB and increasing B-cell lymphoma/leukemia-2 (BCL-2). An increase in NF-κB in isoprenaline-treated rats was in positive correlation with proapoptotic markers (BAX and CC3) and in negative correlation with antiapoptotic marker BCL-2. Liraglutide increased BCL-2 and decreased NF-κB, BAX, and CC3, preserving the same correlations of NF-κB to apoptotic markers. It is concluded that liraglutide protects cardiomyocytes against isoprenaline-induced apoptosis in experimental TT-like myocardial injury through downregulation of the NF-κB pathway.

Aristolochic acid I aggravates oxidative stress-mediated apoptosis by inhibiting APE1/Nrf2/HO-1 signaling

Nephrotoxicity induced by aristolochic acid I (AAI) is related to redox stress and apoptosis. Apurinic/apyrimidine endonuclease 1 (APE1) has antioxidant and anti-apoptotic effects. This study investigated the potential role of APE1 in AAI-induced nephrotoxicity. Renal injury was successfully induced in C57BL/6J mice by intraperitoneal injection of AAI every other day for 28 days. Expressions of APE1, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) in renal tissues of the model mice was inhibited, accompanied by oxidative damage and apoptosis. Similar results were obtained in vitro in human proximal tubular (HK-2) cells damaged by AAI. In the presence of a low concentration of the APE1 inhibitor E3330, expression of Nrf2 and HO-1 proteins in HK-2 cells was decreased and AAI-induced apoptosis was aggravated. Overexpression of APE1 in HK-2 cells promoted the expression of Nrf2 and HO-1, and alleviated apoptosis and renal injury induced by AAI. The collective findings demonstrate that AAI can inhibit the induction of oxidative stress and apoptosis by the APE1/Nrf2/HO-1 axis, leading to AAI renal injury. Targeting APE1 may be an effective therapeutic strategy to treat AA nephrotoxicity.

FUNDC1 interacts with GPx4 to govern hepatic ferroptosis and fibrotic injury through a mitophagy-dependent manner

INTRODUCTION

Liver fibrosis is a life-threatening pathological anomaly which usually evolves into advanced liver cirrhosis and hepatocellular carcinoma although limited therapeutic option is readily available. FUN14 domain containing 1 (FUNDC1) is a mitophagy receptor with little information in liver fibrosis.

OBJECTIVE

This study was designed to examine the role for FUNDC1 in carbon tetrachloride (CCl4)-induced liver injury.

METHODS

GEO database analysis and subsequent validation of biological processes including western blot, immunofluorescence, and co-immunoprecipitation were applied to clarify the regulatory role of FUNDC1 on mitophagy and ferroptosis.

RESULTS

Our data revealed elevated FUNDC1 levels in liver tissues of patients with liver fibrotic injury and CCl4-challenged mice. FUNDC1 deletion protected against CCl4-induced hepatic anomalies in mice. Moreover, FUNDC1 deletion ameliorated CCl4-induced ferroptosis in vivo and in vitro. Mechanically, FUNDC1 interacted with glutathione peroxidase (GPx4), a selenoenzyme to neutralize lipid hydroperoxides and ferroptosis, via its 96-133 amino acid domain to facilitate GPx4 recruitment into mitochondria from cytoplasm. GPx4 entered mitochondria through mitochondrial protein import system-the translocase of outer membrane/translocase of inner membrane (TOM/TIM) complex, prior to degradation of GPx4 mainly through mitophagy along with ROS-induced damaged mitochondria, resulting in hepatocyte ferroptosis.

CONCLUSION

Taken together, our data favored that FUNDC1 promoted hepatocyte injury through GPx4 binding to facilitate its mitochondrial translocation through TOM/TIM complex, where GPx4 was degraded by mitophagy to trigger ferroptosis. Targeting FUNDC1 may be a promising therapeutic approach for liver fibrosis.

Oxidative stress status assessment of rats' brains injury following subacute exposure to K-oximes

Oxidative stress status and morphological injuries in the brain of Wistar rats induced by repeated application of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, K074, and K075 were evaluated. Each oxime in a dose of 0.1 of LD50/kg im was given 2x/week for 4 weeks. Markers of lipid peroxidation (malondialdehyde, MDA), and protein oxidation (advanced oxidation protein products, AOPP), as well as the activity of antioxidant enzymes (catalase, CAT, superoxide dismutase, SOD, glutathione reductase, GR, and glutathione peroxidase, GPx), were estimated in the brain tissue homogenates on day 35 of the study. Brain alterations were carefully quantified by semiquantitative grading scales - brain damage score (BDS). Oxidative stress parameters, MDA and AOPP were significantly highest in the asoxime-, obidoxime- and K075-treated groups (p < 0.001). The activity of SOD and CAT was significantly elevated in the obidoxime-, K048-, and K075-treated groups (p < 0.001). Besides, GR was markedly decreased in the obidoxime- and K074-treated groups (p < 0.01), while treatment with K048, K074 and K075 induced extremely high elevation in GPx levels (p < 0.001). In the same groups of rats, brain alterations associated with polymorphonuclear cell infiltrate were significantly more severe than those observed in animals receiving only asoxime or K027 (p < 0.001). The presented results confirmed that treatment with different oximes significantly improved the oxidative status and attenuated signs of inflammation in rats' brains. Presented results, together with our previously published data can help to predict likely adverse systemic toxic effects, and target organ systems, which are crucial for establishing risk categories, as well as in dose selection of K-oximes as drug candidates.

CIRP attenuates acute kidney injury after hypothermic cardiovascular surgery by inhibiting PHD3/HIF-1α-mediated ROS-TGF-β1/p38 MAPK activation and mitochondrial apoptotic pathways

BACKGROUND

The ischemia-reperfusion (IR) environment during deep hypothermic circulatory arrest (DHCA) cardiovascular surgery is a major cause of acute kidney injury (AKI), which lacks preventive measure and treatment. It was reported that cold inducible RNA-binding protein (CIRP) can be induced under hypoxic and hypothermic stress and may have a protective effect on multiple organs. The purpose of this study was to investigate whether CIRP could exert renoprotective effect during hypothermic IR and the potential mechanisms.

METHODS

Utilizing RNA-sequencing, we compared the differences in gene expression between Cirp knockout rats and wild-type rats after DHCA and screened the possible mechanisms. Then, we established the hypothermic oxygen-glucose deprivation (OGD) model using HK-2 cells transfected with siRNA to verify the downstream pathways and explore potential pharmacological approach. The effects of CIRP and enarodustat (JTZ-951) on renal IR injury (IRI) were investigated in vivo and in vitro using multiple levels of pathological and molecular biological experiments.

RESULTS

We discovered that Cirp knockout significantly upregulated rat Phd3 expression, which is the key regulator of HIF-1α, thereby inhibiting HIF-1α after DHCA. In addition, deletion of Cirp in rat model promoted apoptosis and aggravated renal injury by reactive oxygen species (ROS) accumulation and significant activation of the TGF-β1/p38 MAPK inflammatory pathway. Then, based on the HK-2 cell model of hypothermic OGD, we found that CIRP silencing significantly stimulated the expression of the TGF-β1/p38 MAPK inflammatory pathway by activating the PHD3/HIF-1α axis, and induced more severe apoptosis through the mitochondrial cytochrome c-Apaf-1-caspase 9 and FADD-caspase 8 death receptor pathways compared with untransfected cells. However, silencing PHD3 remarkably activated the expression of HIF-1α and alleviated the apoptosis of HK-2 cells in hypothermic OGD. On this basis, by pretreating HK-2 and rats with enarodustat, a novel HIF-1α stabilizer, we found that enarodustat significantly mitigated renal cellular apoptosis under hypothermic IR and reversed the aggravated IRI induced by CIRP defect, both in vitro and in vivo.

CONCLUSION

Our findings indicated that CIRP may confer renoprotection against hypothermic IRI by suppressing PHD3/HIF-1α-mediated apoptosis. PHD3 inhibitors and HIF-1α stabilizers may have clinical value in renal IRI.

Investigating the effect of dehydromiltirone on septic AKI using a network pharmacology method, molecular docking, and experimental validation

Acute kidney injury (AKI) is a severe and frequent complication of sepsis that occurs in intensive care units with inflammation and rapid decline in renal function as the main pathological features. Systemic inflammation, microvascular dysfunction, and tubule injury are the main causes of sepsis-induced AKI (SI-AKI). The high prevalence and death rate from SI-AKI is a great challenge for clinical treatment worldwide. However, in addition to hemodialysis, there is no effective drug to improve renal tissue damage and alleviate the decline in kidney function. We conducted a network pharmacological analysis of Salvia miltiorrhiza (SM), a traditional Chinese medicine, which is widely used for the treatment of kidney disease. Then, we combined molecular docking and a dynamics simulation to screen for the active monomer dehydromiltirone (DHT) that has therapeutic effects on SI-AKI and investigated its potential mechanism of action through experimental validation. The components and targets of SM were obtained by searching the database, and 32 overlapping genes were screened by intersection analysis with AKI targets. GO and KEGG data showed that the functions of a common gene were closely related to oxidative stress, mitochondrial function, and apoptosis. The molecular docking results combined with molecular dynamics simulations provide evidence for a binding model between DHT and cyclooxygenase-2 (COX2), both of which are mainly driven by van der Waals interactions and a hydrophobic effect. In vivo, we found that mice pretreated with an intraperitoneal injection of DHT (20 mg/kg/d) for 3 days ameliorated CLP surgery-induced renal function loss and renal tissue damage and inhibited inflammatory mediators IL-6, IL-1β, TNF-α, and MCP-1 production. In vitro, the DHT pretreatment decreased LPS-induced expression of COX2, inhibited cell death and oxidative stress, alleviated mitochondrial dysfunction, and restrained apoptosis in HK-2 cells. Our research indicates that the renal preventive effect of DHT is related to maintaining mitochondrial dynamic balance, restoring mitochondrial oxidative phosphorylation, and inhibiting cell apoptosis. The findings in this study provide a theoretical basis and a novel method for the clinical therapy of SI-AKI.

Kluyveromyces marxianus Ameliorates High-Fat-Diet-Induced Kidney Injury by Affecting Gut Microbiota and TLR4/NF-κB Pathway in a Mouse Model

Objectives. The effects of Kluyveromyces marxianus on high-fat diet- (HFD-) induced kidney injury (KI) were explored. Methods. HFD-induced KI model was established using male C57BL/6 mice and treated with K. marxianus JLU-1016 and acid-resistant (AR) strain JLU-1016A. Glucose tolerance was evaluated via an oral glucose tolerance test (OGTT). KI was measured using Hematoxylin and Eosin (H&E) staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis. The chemical indexes were analyzed, including lipid profiles, inflammatory cytokines, and creatinine. The levels of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) or phospho-NF-κB p65 (Ser536) and alpha inhibitor of NF-κB (IκBα) were measured using qPCR and Western blot. The gut microbiota was sequenced using high-throughput sequencing. Results. HFD induction increased OGTT value, KI severity, oxidative stress, inflammatory cytokines, oxidative stress, apoptotic rate, creatinine levels, and the expression of TLR4/NF-κB, phospho-NF-κB p65 (Ser536), and IκBα deteriorated lipid profiles ( $P<0.05$ ) and reduced gut microbiota abundance. K. marxianus treatment ameliorated HFD-induced metabolic disorders and reversed these parameters ( $P<0.05$ ). Compared with the control, HFD induction increased the proportion of Firmicutes but reduced the proportion of Bacteroidetes and Lactobacillus. K. marxianus JLU-1016 and AR strain JLU-1016A treatments improved gut microbiota by reducing the proportion of Firmicutes and increasing the proportion of Bacteroidetes and Lactobacillus in the KI model ( $P<0.0001$ ). Helicobacter has been identified with many infectious diseases and was increased after HFD induction and inhibited after K. marxianus JLU-1016 and AR strain JLU-1016A treatments. The strain JLU-1016A exhibited better results possibly with acid-tolerance properties to pass through an acidic environment of the stomach. Conclusions. K. marxianus may have a beneficial effect on KI by improving gut microbiota and inhibiting TLR4/NF-κB pathway activation.

Association between septic patient mortality and blood survivin concentrations

OBJECTIVE

Survivin is a member of inhibitors of apoptosis proteins family. There are not data about the association between mortality of septic patients and blood survivin concentrations. Therefore, the objective of this study was to determine whether exist that association.

DESIGN

Observational and prospective study.

SETTING

Three Spanish Intensive Care Units.

PATIENTS

Patients with sepsis or septic shock according to Sepsis-3 Consensus criteria.

INTERVENTIONS

Serum survivin concentrations were determined at moment of sepsis diagnosis.

MAIN VARIABLE OF INTEREST

Mortality at 30 days.

RESULTS

A total of 204 patients were included in the study, of which 75 (36.8%) died in the first 30 days. Lower age (p<0.001), serum lactic acid levels (p=0.001), rate of septic shock (p=0.001) and SOFA (p<0.001), and higher serum survivin levels (p=0.001) exhibited surviving (n=129) than non-surviving patients (n=75). We found in multiple logistic regression analysis an association between serum survivin concentrations and mortality independently of SOFA, lactic acid, age, INR, activated partial thromboplastin time (aPTT) and empiric antimicrobial treatment adequate (OR=0.968; 95% CI=0.946-0.990; p=0.005), and also independently of APACHE-II, lactic acid, platelet, INR, aPTT and empiric antimicrobial treatment adequate (OR=0.966; 95% CI=0.943-0.989; p=0.004).

CONCLUSIONS

There is an association between septic patient mortality and low blood survivin concentrations.

Resveratrol improved kidney function and structure in malignantly hypertensive rats by restoration of antioxidant capacity and nitric oxide bioavailability

BACKGROUND

The main cause of death among patients with malignant hypertension is a kidney failure. The promising field in essential and malignant hypertension therapy could be centered on the amelioration of oxidative stress using antioxidant molecules like resveratrol. Resveratrol is a potent antioxidative agent naturally occurred in many plants that possess health-promoting properties.

METHODS

In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with anti-oxidative activity, in N^G-L-Arginine Methyl Ester (L-NAME) treated spontaneously hypertensive rats (SHR) - malignantly hypertensive rats (MHR).

RESULTS

Resveratrol significantly improves oxidative damages by modulation of antioxidant enzymes and suppression of prooxidant factors in the kidney tissue of MHR. Enhanced antioxidant defense in the kidney improves renal function and ameliorates the morphological changes in this target organ. Besides, protective properties of resveratrol are followed by the restoration of the nitrogen oxide (NO) pathway. 4) Conclusion: Antioxidant therapy with resveratrol could represent promising therapeutical approach in hypertension, especially malignant, against kidney damage.

Gut Barrier in Critical States of the Body

The intestinal barrier (IB) is a system of diffusion barriers separating the intestinal chyme and blood. The aim of the review is to identify the role of IB dysfunction in the formation of critical states of the body and to substantiate ways to prevent these states. Toxic substances produced by normal intestinal microflora are characterized. The involvement of endotoxin and ammonia in the pathogenesis of sepsis, acute circulatory disorders, secondary acute pulmonary lesions, and acute cerebral insufficiency is shown. Approaches to protect the IB in critical states of the body are proposed.

Secondary Dysfunction of the Intestinal Barrier in the Pathogenesis of Complications of Acute Poisoning

The last decade has been marked by an exponential increase in the number of publications on the physiological role of the normal human gut microbiota. The idea of a symbiotic relationship between the human organism and normal microbiota of its gastrointestinal tract has been firmly established as an integral part of the current biomedical paradigm. However, the type of this symbiosis varies from mutualism to parasitism and depends on the functional state of the host organism. Damage caused to the organism by external agents can lead to the emergence of conditionally pathogenic properties in the normal gut microbiota, mediated by humoral factors and affecting the outcome of exogenous exposure. Among the substances produced by symbiotic microbiota, there are an indefinite number of compounds with systemic toxicity. Some occur in the intestinal chyme in potentially lethal amounts in the case they enter the bloodstream quickly. The quick entry of potential toxicants is prevented by the intestinal barrier (IB), a set of structural elements separating the intestinal chyme from the blood. Hypothetically, severe damage to the IB caused by exogenous toxicants can trigger a leakage and subsequent systemic redistribution of toxic substances of bacterial origin. Until recently, the impact of such a redistribution on the outcome of acute exogenous poisoning remained outside the view of toxicology. The present review addresses causal relationships between the secondary dysfunction of the IB and complications of acute poisoning. We characterize acute systemic toxicity of such waste products of the normal gut microflora as ammonia and endotoxins, and demonstrate their involvement in the formation of such complications of acute poisoning as shock, sepsis, cerebral insufficiency and secondary lung injuries. The principles of assessing the functional state of the IB and the approaches to its protection in acute poisoning are briefly considered.

Programmed Cell Death in Sepsis Associated Acute Kidney Injury

Sepsis-associated acute kidney injury (SA-AKI) is common in patients with severe sepsis, and has a high incidence rate and high mortality rate in ICU patients. Most patients progress to AKI before drug treatment is initiated. Early studies suggest that the main mechanism of SA-AKI is that sepsis leads to vasodilation, hypotension and shock, resulting in insufficient renal blood perfusion, finally leading to renal tubular cell ischemia and necrosis. Research results in recent years have shown that programmed cell death such as apoptosis, necroptosis, pyroptosis and autophagy play important roles. In the early stage of sepsis-related AKI, autophagy bodies form and inhibit various types of programmed cell death. With the progress of disease, programmed cell death begins. Apoptosis promoter represents caspase-8-induced apoptosis and apoptosis effector represents caspase-3-induced apoptosis, however, caspase-11 and caspase-1 regulate gasdermin D-mediated pyroptosis. Caspase-8 and receptor interacting kinase 1 bodies mediate necroptosis. This review focuses on the pathophysiological mechanisms of various programmed cell death in sepsis-related AKI.

The pathological role of damaged organelles in renal tubular epithelial cells in the progression of acute kidney injury

Acute kidney injury (AKI) is a common clinical condition associated with high morbidity and mortality. The pathogenesis of AKI has not been fully elucidated, with a lack of effective treatment. Renal tubular epithelial cells (TECs) play an important role in AKI, and their damage and repair largely determine the progression and prognosis of AKI. In recent decades, it has been found that the mitochondria, endoplasmic reticulum (ER), lysosomes, and other organelles in TECs are damaged to varying degrees in AKI, and that they can influence each other through various signaling mechanisms that affect the recovery of TECs. However, the association between these multifaceted signaling platforms, particularly between mitochondria and lysosomes during AKI remains unclear. This review summarizes the specific pathophysiological mechanisms of the main TECs organelles in the context of AKI, particularly the potential interactions among them, in order to provide insights into possible novel treatment strategies.

Amelioration of Endotoxin-Induced Acute Lung Injury and Alveolar Epithelial Cells Apoptosis by Simvastatin Is Associated with Up-Regulation of Survivin/NF-kB/p65 Pathway

Disruption of the alveolar−endothelial barrier caused by inflammation leads to the progression of septic acute lung injury (ALI). In the present study, we investigated the beneficial effects of simvastatin on the endotoxin lipopolysaccharide (LPS)-induced ALI and its related mechanisms. A model of ALI was induced within experimental sepsis developed by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment (10−40 mg/kg orally). The severity of the lung tissue inflammatory injury was expressed as pulmonary damage scores (PDS). Alveolar epithelial cell apoptosis was confirmed by TUNEL assay (DNA fragmentation) and expressed as an apoptotic index (AI), and immunohistochemically for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL, an inhibitor of apoptosis, survivin, and transcriptional factor, NF-kB/p65. Severe inflammatory injury of pulmonary parenchyma (PDS 3.33 ± 0.48) was developed after the LPS challenge, whereas simvastatin significantly and dose-dependently protected lung histology after LPS (p < 0.01). Simvastatin in a dose of 40 mg/kg showed the most significant effects in amelioration alveolar epithelial cells apoptosis, demonstrating this as a marked decrease of AI (p < 0.01 vs. LPS), cytochrome C, and cleaved caspase-3 expression. Furthermore, simvastatin significantly enhanced the expression of Bcl-xL and survivin. Finally, the expression of survivin and its regulator NF-kB/p65 in the alveolar epithelium was in strong positive correlation across the groups. Simvastatin could play a protective role against LPS-induced ALI and apoptosis of the alveolar−endothelial barrier. Taken together, these effects were seemingly mediated by inhibition of caspase 3 and cytochrome C, a finding that might be associated with the up-regulation of cell-survival survivin/NF-kB/p65 pathway and Bcl-xL.

The Programmed Cell Death of Macrophages, Endothelial Cells, and Tubular Epithelial Cells in Sepsis-AKI

Sepsis is a systemic inflammatory response syndrome caused by infection, following with acute injury to multiple organs. Sepsis-induced acute kidney injury (AKI) is currently recognized as one of the most severe complications related to sepsis. The pathophysiology of sepsis-AKI involves multiple cell types, including macrophages, vascular endothelial cells (ECs) and renal tubular epithelial cells (TECs), etc. More significantly, programmed cell death including apoptosis, necroptosis and pyroptosis could be triggered by sepsis in these types of cells, which enhances AKI progress. Moreover, the cross-talk and connections between these cells and cell death are critical for better understanding the pathophysiological basis of sepsis-AKI. Mitochondria dysfunction and oxidative stress are traditionally considered as the leading triggers of programmed cell death. Recent findings also highlight that autophagy, mitochondria quality control and epigenetic modification, which interact with programmed cell death, participate in the damage process in sepsis-AKI. The insightful understanding of the programmed cell death in sepsis-AKI could facilitate the development of effective treatment, as well as preventive methods.

ATRvD1 Attenuates Renal Tubulointerstitial Injury Induced by Albumin Overload in Sepsis-Surviving Mice

Novel strategies for the prevention and treatment of sepsis-associated acute kidney injury and its long-term outcomes have been required and remain a challenge in critical care medicine. Therapeutic strategies using lipid mediators, such as aspirin-triggered resolvin D1 (ATRvD1), can contribute to the resolution of acute and chronic inflammation. In this study, we examined the potential effect of ATRvD1 on long-term kidney dysfunction after severe sepsis. Fifteen days after cecal ligation and puncture (CLP), sepsis-surviving BALB/c mice were subjected to a tubulointerstitial injury through intraperitoneal injections of bovine serum albumin (BSA) for 7 days, called the subclinical acute kidney injury (subAKI) animal model. ATRvD1 treatment was performed right before BSA injections. On day 22 after CLP, the urinary protein/creatinine ratio (UPC), histologic parameters, fibrosis, cellular infiltration, apoptosis, inflammatory markers levels, and mRNA expression were determined. ATRvD1 treatment mitigated tubulointerstitial injury by reducing proteinuria excretion, the UPC ratio, the glomerular cell number, and extracellular matrix deposition. Pro-fibrotic markers, such as transforming growth factor β (TGFβ), type 3 collagen, and metalloproteinase (MMP)-3 and -9 were reduced after ATRvD1 administration. Post-septic mice treated with ATRvD1 were protected from the recruitment of IBA1⁺ cells. The interleukin-1β (IL-1β) levels were increased in the subAKI animal model, being attenuated by ATRvD1. Tumor necrosis factor-α (TNF-α), IL-10, and IL-4 mRNA expression were increased in the kidney of BSA-challenged post-septic mice, and it was also reduced after ATRvD1. These results suggest that ATRvD1 protects the kidney against a second insult such as BSA-induced tubulointerstitial injury and fibrosis by suppressing inflammatory and pro-fibrotic mediators in renal dysfunction after sepsis.

Apoptosis detection: a purpose-dependent approach selection

Apoptosis is closely associated with many diseases. Detection of apoptosis can be achieved by morphology, biochemistry, molecular biology, immunology, and other techniques. However, as technologies are increasingly used for the detection of apoptosis, many researchers are confused about how to choose a suitable method to detect apoptosis. Selection of a suitable detection method for apoptosis will help clinical diagnosis and prevention of diseases. This article reviews the selection of optimal apoptosis-detection methods based on research purposes and technique principles.