Septic Acute Kidney Injury Research Articles

Long-Term Preservation of Renal Function in Septic Shock Burn Patients Requiring Renal Replacement Therapy for Acute Kidney Injury.

Background. The real impact of septic shock-associated acute kidney injury (AKI) on the long-term renal outcome is still debated, and little is known about AKI-burn patients. In a cohort of burn survivors treated by continuous renal replacement therapy (CRRT) and sorbent technology (CPFA-CRRT), we investigated the long-term outcome of glomerular and tubular function. Methods. Out of 211 burn patients undergoing CRRT from 2001 to 2017, 45 survived, 40 completed the clinical follow-up (cumulative observation period 4067 months, median 84 months, IR 44-173), and 30 were alive on 31 December 2020. Besides creatinine and urine albumin, in the 19 patients treated with CPFA-CRRT, we determined the normalized GFR by 99mTc-DTPA (NRI-GFR) and studied glomerular and tubular urine protein markers. Results. At the follow-up endpoint, the median plasma creatinine and urine albumin were 0.99 (0.72–1.19) and 0.0 mg/dL (0.0–0.0), respectively. NRI-GFR was 103.0 mL/min (93.4–115). Four patients were diabetic, and 22/30 presented at least one risk factor for chronic disease (hypertension, dyslipidemia, and overweight). Proteinuria decreased over time, from 0.47 g/day (0.42–0.52) at 6 months to 0.134 g/day (0.09–0.17) at follow-up endpoint. Proteinuria positively correlated with the peak of plasma creatinine (r 0.6953, p 0.006) and the number of CRRT days (r 0.5650, p 0.035) during AKI course, and negatively with NRI–GFR (r −0.5545, p 0.049). In seven patients, urine protein profile showed a significant increase of glomerular marker albumin and glomerular/tubular index. Conclusions. Burn patients who experienced septic shock and AKI treated with CRRT had a long-term expectation of preserved renal function. However, these patients were more predisposed to microalbuminuria, diabetes, and the presence of risk factors for intercurrent comorbidities and chronic renal disease.

Non-invasive Early Prediction of Septic Acute Kidney Injury by Doppler-Based Renal Resistive Indexes Combined With Echocardiographic Parameters: An Experimental Study

Non-invasive early prediction of septic acute kidney injury (S-AKI) is still urgent and challenging. Increased Doppler-based renal resistive index (RRI) has been shown to be associated with S-AKI, but its clinical use is limited, which may be explained by the complex effects of systemic circulation. Echocardiogram allows non-invasive assessment of systemic circulation, which may provide an effective supplement to RRI. To find the value of RRI combined with echocardiographic parameters in the non-invasive early prediction of S-AKI, we designed this experiment with repeated measurements of ultrasonographic parameters in the early stage of sepsis (3, 6, 12, and 24 h) in cecum ligation and puncture (CLP) rats (divided into AKI and non-AKI groups at 24 h based on serum creatinine), with sham-operated group serving as controls. Our results found that RRI alone could not effectively predict S-AKI, but when combined with echocardiographic parameters (heart rate, left ventricular end-diastolic internal diameter, and left ventricular end-systolic internal diameter), the predictive value was significantly improved, especially in the early stage of sepsis (3 h, AUC: 0.948, 95% CI 0.839–0.992, P < 0.001), and far earlier than the conventional renal function indicators (serum creatinine and blood urea nitrogen), which only significantly elevated at 24 h. Our method showed novel advances and potential in the early detection of S-AKI.

Association between albumin infusion and outcomes in patients with acute kidney injury and septic shock

Septic shock with acute kidney injury (AKI) is common in critically ill patients. Our aim was to evaluate the association between albumin infusion and outcomes in patients with septic shock and AKI. Medical Information Mart for Intensive Care (MIMIC)-III was used to identify patients with septic shock and AKI. Propensity score matching (PSM) was employed to balance the baseline differences. Cox proportional hazards model, Wilcoxon rank-sum test, and logistic regression were utilized to determine the associations of albumin infusion with mortality, length of stay, and recovery of kidney function, respectively. A total of 2861 septic shock patients with AKI were studied, including 891 with albumin infusion, and 1970 without albumin infusion. After PSM, 749 pairs of patients were matched. Albumin infusion was associated with improved 28-day survival (HR 0.72; 95% CI 0.59–0.86; P = 0.002), but it was not difference in 90-day mortality between groups (HR 0.94; 95% CI 0.79–1.12; P = 0.474). Albumin infusion was not associated with the renal function recovery (HR 0.91; 95% CI 0.73–1.13; P = 0.393) in either population. Nevertheless, subgroup analysis showed that albumin infusion was distinctly associated with reduced 28-day mortality in patients with age > 60 years. The results need to be validated in more randomized controlled trials.

Maresin conjugates in tissue regeneration-1 suppresses ferroptosis in septic acute kidney injury

BackgroundFerroptosis is unique among different types of regulated cell death and closely related to organ injury. Whether ferroptosis occurs in sepsis-associated acute kidney injury (SA-AKI) is not clear. Nuclear factor-erythroid-2-related factor 2 (Nrf2) is crucial to the regulation of ferroptosis. We and others have shown that Maresin conjugates in tissue regeneration 1 (MCTR1) or other members of specialized pro-resolving mediators (SPMs) can actively regulate inflammation resolution and protect organs against injury in inflammatory diseases by activating the Nrf2 signaling. The aim of this study was to determine whether ferroptosis occurs in SA-AKI. Furthermore, we investigated the potential role and mechanism of MCTR1 in the regulation of ferroptosis in SA-AKI, which mainly focus on the Nrf2 signaling.ResultsWe demonstrated for the first time that ferroptosis is present in SA-AKI. Moreover, MCTR1 effectively suppressed ferroptosis in SA-AKI. Meanwhile, MCTR1 upregulated the expression of Nrf2 in the kidney of septic mice. Nrf2 inhibitor ML-385 reversed MCTR1-regulated ferroptosis and AKI, implying that Nrf2 is involved in the inhibitory effects of MCTR1 on ferroptosis in SA-AKI. Further, MCTR1 inhibited ferroptosis and elevated the expression of Nrf2 in LPS-induced HK-2 cells. However, Nrf2 siRNA offset the effect of MCTR1 on ferroptosis. Finally, we observed that MCTR1 ameliorates multi-organ injury and improves survival in animal models of sepsis.ConclusionsThese data demonstrate that MCTR1 suppresses ferroptosis in SA-AKI through the Nrf2 signaling. Our study enriches the pathophysiological mechanism of SA-AKI and provides new therapeutic ideas and potential intervention targets for SA-AKI.

A Modified Rat Model of Cecal Ligation and Puncture for Adjusting the Severity of Septic Acute Kidney Injury

Abstract Background: We aimed to establish a modified cecal ligation and puncture (CLP) rat model with omentectomy for simulating moderate-to-severe septic kidney injury (AKI). Subjects and Methods: Rats were randomly divided into four groups subjected to: Traditional CLP (n = 40); the modified CLP procedure (n = 40); sham surgery (abdominal incision only) (n = 6); and abdominal incision and omentectomy only (n = 6). We evaluated the severity of renal injury according to serum creatinine levels at 0, 24, and 48 h postoperatively and cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) levels at 12 h postoperatively, graded the severity of sepsis, monitored the degree of peritonitis, and examined animal survival. Results: Compared with the traditional CLP group, the modified CLP group developed more severe sepsis at postoperative 48 h, had more severe renal pathology, and developed more severe AKI with high homogeneity. Most rats in the traditional CLP group exhibited complete wrapping of the puncture site by omentum with limited peritonitis, while partial wrapping with pus spreading was observed in some. All rats in the modified CLP group developed puncture site necrosis, with pus spreading without formation of an encapsulated abscess, and a consistent degree of peritonitis. The 7-day survival rates in the traditional and modified CLP groups were 65.0% and 50.0%, respectively. Conclusion: The traditional CLP approach was associated with an even distribution of different AKI severities among treated animals, whereas the modified CLP approach established a consistently more severe rat model of septic AKI, constituting an important advance for optimizing septic AKI animal models.

PREDICTORS IN-HOSPITAL MORTALITY OF SEPTIC VS NON-SEPTIC ACUTE KIDNEY INJURY PATIENTS: AN OBSERVATIONAL COHORT STUDY

Background: To compare the predictors In-hospital mortality of patients with septic Acute Kidney Injury (S-AKI) and non-septic AKI (NS-AKI). Methods: a cohort study of critically ill patients with AKI admitted to the emergency room at a tertiary hospital from January to June 2019. The primary outcome was hospital mortality. Results: There were 116 patients who met the inclusion criteria. Compared with NS-AKI, patients with S-AKI had significantly lower mean MAP, median eGFR, and urine output. (UO). S-AKI had higher mortality and vasopressor requirements and had a lower renal recovery than NS-AKI (63.2% vs 31.4%, p=0.001; 30.8% vs 13.7%, p=0.031, and 36.9% vs 60.8%, p=0.011, respectively). AKI stage 3 and vasopressor requirements were dependent risk factors for both S-AKI and NS-AKI mortality. Meanwhile, SOFA score &gt; 7 and the need for dialysis are dependent and independent risk factors for mortality in S-AKI. Worsening and/or persistence in UO, serum urea and creatinine levels at 48 h after admission were predictors of mortality in S-AKI and NS-AKI. Improvement in UO in surviving patients was more pronounced in S-AKI than in NS-AKI (50% vs 17.1%, p=0.007). The surviving S-AKI patients had a longer hospital stay than surviving NS-AKI [8 (6-14.5) vs 5 (4 – 8), p=0.004]. S-AKI have higher mortality and vasopressor requirements and have lower renal recovery than NS-AKI. Conclusion: S-AKI have higher mortality and vasopressor requirements and a lower renal recovery than NS-AKI. Independent predictors of mortality in S-AKI were high SOFA scores and the need for dialysis.

Impact of Cumulative Fluid Balance During Continuous Renal Replacement Therapy on Mortality in Patients With Septic Acute Kidney Injury: A Retrospective Cohort Study

Background: The clinicians often use continuous renal replacement therapy (CRRT) for the fluid management of patients with septic acute kidney injury (AKI). However, there is limited knowledge of the effects of changes in fluid balance (FB) on CRRT and its association with outcomes in patients with septic AKI.Objective: This study aimed to determine the association of cumulative FB (CFB) during treatment with 28-day all-cause mortality in the patients with septic AKI who require CRRT.Methods: This retrospective observational study examined patients who received CRRT due to septic AKI in a mixed intensive care unit (ICU) of a tertiary teaching hospital between January 2015 and December 2018. The patients were divided into three groups—negative FB, even FB, and positive FB—based on the CFB during CRRT. The primary outcome was 28-day all-cause mortality.Results: We examined 227 eligible patients and the mean age was 62.4 ± 18.3 years. The even FB group had a significantly lower 28-day mortality (43.0%, p = 0.007) than the positive FB group (72.7%) and the negative FB group (54.8%). The unadjusted and adjusted Cox regression models indicated that the positive FB group had an increased risk for 28-day all-cause mortality relative to the even FB group. A restricted cubic splines model indicated a J-shaped association between the CFB and 28-day all-cause mortality in the unadjusted model.Conclusion: Among the critically ill patients with septic AKI who require CRRT, those with positive FB had a higher mortality rate than those with even FB.

Clinical and economic assessment of the therapy of acute kidney injury in sepsis with continuous combined methods of renal replacement therapy

Objective: complex assessment of clinical and economic effectiveness as well as saving of the state budget assets within the therapy of patients with sepsis/septic shock based on different technologies of blood purification.Methods. Evaluation of direct and indirect costs of the eight blood purifcation methods. The target population includes adult patients 18+ with septic acute kidney injury. The study was conducted in compliance with acting Standards on Clinical Economic Studies used in the Russian Federation.The study methods included evaluation of existing randomized clinical studies and trials with data from network meta-analyses and systematic reviews of the target technologies. The direct medical and indirect non-medical costs were calculated and analyzed in respect of cost-effectiveness and budget impact analyses.Results. Direct and indirect costs were calculated for the sorption devices oXiris (Baxter International Inc.), Toraymyxin (Toray Medical Co.), Alteco LPS Adsorber (Alteco Medical AB), Toxipak (POKARD NPF), Desepta.LPS (BIOTECH M NPP), CytoSorb (CytoSorbents Inc.), HA330 (Jafron Biomedical Co.), Desepta (BIOTECH M NPP) for two time-horizons: 1-year period and 5-years period with discounting. For both periods, the use of oXiris hemoflter results in the least economic burden for the state budget.Conclusion. The use of blood purifcation in septic patients therapy is associated with considerable direct and indirect fnancial expenses, the amount of which and consequential budget saving depend on the technology of blood purifcation applied. The actual tariff compensation policy evidently demands revising.

Circ_0114427 promotes LPS-induced septic acute kidney injury by modulating miR-495-3p/TRAF6 through the NF-κB pathway

Backgrounds Septic acute kidney injury (AKI) is a severe illness in clinics. Enriching researches investigated the regulatory network of AKI during the past decades, evidences showed that circular RNAs (circRNAs) were involved in the molecular mechanism of human AKI. However, the special responses remain largely elusive. Thus, the study aims to investigate the function of circ_0114427 in the progression of AKI. Methods The levels of circ_0114427, miR-495-3p and Tumour Necrosis Factor Receptor-Associated Factor 6 (TRAF6) were both assessed by quantitative real-time polymerase chain reaction (qRT-PCR). In addition, lipopolysaccharide (LPS) was applied to establish AKI cell model, and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was carried out to determine the viability of LPS-induced HK-2 cells. The expression of TRAF6, B-cell lymphoma-2 (Bcl-2), Bcl2-associated X (Bax), cleave-caspase 3, caspase 3, total IκBα (t-IκBα), phospho-IκBα (p-IκBα), total p65 (t-p65) and phospho-p65 (p-p65) were all detected via western blot. The levels of IL-1β and TNF-α were identified by western blot and ELISA. What’s more, cell apoptosis was measured by flow cytometry. Lastly, dual-luciferase reporter, RNA Immunoprecipitation (RIP) and RNA pull-down assays were employed to verify the relationships between miR-495-3p and circ_0114427 or TRAF6 in vitro. Results The level of miR-495-3p was remarkably restrained while circ_0114427 and TRAF6 levels were specially reinforced in AKI patient serum samples and LPS-induced HK-2 cells. Moreover, IL-1β and TNF-α were highly expressed in LPS-induced AKI cells. Functionally, circ_0114427 was a sponge of miR-495-3p, and circ_0114427 silence-mediated effects in LPS-induced HK-2 cells were partly ameliorated by the addition of miR-495-3p inhibitor. Moreover, TRAF6 was a target gene of miR-495-3p, and the inhibiting effect of miR-495-3p on cell apoptosis and inflammatory response was mitigated by TRAF6 overexpression. Mechanistically, the circ_0114427/miR-495-3p/TRAF6 axis modulated cell apoptosis and inflammatory response via NF-κB/p65 signalling pathway in AKI. Conclusion Circ_0114427 regulated cell apoptosis and inflammatory response through miR-495-3p/TRAF6 axis via NF-κB/p65 signalling pathway, providing a novel mechanism in clinical treatment of AKI patients. Highlights Circ_0114427 is upregulated in serum specimens from septic AKI patients and LPS-induced HK-2 cells. LPS treatment suppresses cell viability and promotes apoptosis and inflammation in HK-2 cells. Circ_0114427 knockdown ameliorates the effects of LPS on cell viability, apoptosis and inflammation in HK-2 cells. Circ_0114427 regulates LPS-induced HK-2 cell injury by regulating miR-495-3p/TRAF6/NF-κB/p65 axis.

KLF6 Promotes Pyroptosis of Renal Tubular Epithelial Cells in Septic Acute Kidney Injury.

Septic acute kidney injury (SAKI) represents a clinical challenge with high morbidity and mortality. The current study aimed to analyze the effects and molecular mechanism of Krüppel-like factor 6 (KLF6) on SAKI. First, SAKI mouse models were established by cecum ligation and puncture, while in vivo cell models were established using lipopolysaccharide (LPS). RT-qPCR assay was subsequently performed to detect the levels of KLF6 mRNA. SAKI mice and LPS-treated TCMK-1 cells were further treated with KLF6 siRNA. Afterward, HE staining, PAS staining, Western blot assay, and ELISA were adopted to ascertain the effects of KLF6 in pyroptosis. The binding relationships between KLF6 and miR-223-3p promoter /miR-223-3p and NLRP3 were analyzed with the help of CHIP and dual-luciferase reporter assays. RT-qPCR was adopted to determine the expression patterns of miR-223-3p and NLRP3. Lastly, a rescue experiment was designed to confirm the role of miR-223-3p. It was found that KLF6 was highly expressed in SAKI, whereas knockdown of KLF6 alleviated oxidative stress (OS) and pyroptosis in SAKI mice and LPS-treated TCMK-1 cells. Mechanistic results confirmed that KLF6 inhibited miR-223-3p via binding to the miR-223-3p promoter and promoted NLRP3. On the other hand, downregulation of miR-223-3p activated the NLRP3/Caspase-1/IL-1β pathway and aggravated OS and pyroptosis. Overall, our findings indicated that KLF6 inhibited miR-223-3p via binding to the miR-223-3p promoter and promoted NLRP3, and activated the NLRP3/Caspase-1/IL-1β pathway, thereby aggravating pyroptosis and SAKI.

The Therapeutic Effects of Curcumin in Early Septic Acute Kidney Injury: An Experimental Study.

PurposeSepsis is the leading condition associated with acute kidney injury (AKI) in the hospital and intensive care unit (ICU), sepsis-induced AKI (S-AKI) is strongly associated with poor clinical outcomes. Curcumin possesses an ability to ameliorate renal injury from ischemia-reperfusion, but it is still unknown whether they have the ability to reduce S-AKI. The aim of this study was to investigate the protective effects of curcumin on S-AKI and to assess its therapeutic potential on renal function, inflammatory response, and microcirculatory perfusion.MethodsMale Sprague-Dawley (SD) rats underwent cecal ligation and puncture (CLP) to induce S-AKI and immediately received vehicle (CLP group) or curcumin (CLP+Cur group) after surgery. At 12 and 24h after surgery, serum indexes, inflammatory factors, cardiac output (CO), renal blood flow and microcirculatory flow were measured.ResultsSerum levels of creatinine (Scr), cystatin C (CysC), IL-6 and TNF-α were significantly lower in the CLP+Cur group than those in the CLP group (P < 0.05). Treatment with curcumin improved renal microcirculation at 24h by measurement of contrast enhanced ultrasound (CEUS) quantitative parameters [peak intensity (PI); half of descending time (DT/2); area under curve (AUC); P < 0.05]. In histopathological analysis, treatment with curcumin reduced damage caused by CLP.ConclusionCurcumin can alleviate S-AKI in rats by improving renal microcirculatory perfusion and reducing inflammatory response. Curcumin may be a potential novel therapeutic agent for the prevention or reduction of S-AKI.

Circ_RASGEF1B Promotes LPS-Induced Apoptosis and Inflammatory Response by Targeting MicroRNA-146a-5p/Pdk1 Axis in Septic Acute Kidney Injury Cell Model

Background: We intended to investigate the function of circular RNA RasGEF domain family member 1B (circ_RASGEF1B) in lipopolysaccharide (LPS)-induced septic acute kidney injury (AKI) cell model and its associated mechanism. Methods: TCMK-1 cells were exposed to 10 μg/mL LPS for 24 h to establish a septic AKI cell model. Mice were intraperitoneally injected with 10 mg/kg LPS to establish a septic AKI mice model. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were used to measure RNA and protein expression, respectively. Cell viability and apoptosis were assessed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Cell inflammatory response was analyzed using enzyme-linked immunosorbent assay. Dual-luciferase reporter assay was conducted to confirm the predicted target relationship between microRNA-146a-5p (miR-146a-5p) and circ_RASGEF1B or pyruvate dehydrogenase kinase 1 (Pdk1). Results: The circ_RASGEF1B level was upregulated in LPS-induced TCMK-1 cells and septic AKI mice models. LPS exposure reduced cell viability and promoted cell apoptosis and inflammatory response partly by upregulating circ_RASGEF1B. Circ_RASGEF1B bound to miR-146a-5p and miR-146a-5p interference partly overturned circ_RASGEF1B silencing-mediated effects in LPS-induced TCMK-1 cells. Pdk1 was a target of miR-146a-5p, and Pdk1 accumulation partly counteracted miR-146a-5p-induced influences in TCMK-1 cells upon LPS stimulation. Conclusion: Circ_RASGEF1B promoted LPS-induced apoptosis and inflammatory response in renal tubular epithelial cells partly by upregulating Pdk1 via acting as miR-146a-5p sponge.

Targeting Oxidative Stress in Septic Acute Kidney Injury: From Theory to Practice.

Sepsis is the leading cause of acute kidney injury (AKI) and leads to increased morbidity and mortality in intensive care units. Current treatments for septic AKI are largely supportive and are not targeted towards its pathophysiology. Sepsis is commonly characterized by systemic inflammation and increased production of reactive oxygen species (ROS), particularly superoxide. Concomitantly released nitric oxide (NO) then reacts with superoxide, leading to the formation of reactive nitrogen species (RNS), predominantly peroxynitrite. Sepsis-induced ROS and RNS can reduce the bioavailability of NO, mediating renal microcirculatory abnormalities, localized tissue hypoxia and mitochondrial dysfunction, thereby initiating a propagating cycle of cellular injury culminating in AKI. In this review, we discuss the various sources of ROS during sepsis and their pathophysiological interactions with the immune system, microcirculation and mitochondria that can lead to the development of AKI. We also discuss the therapeutic utility of N-acetylcysteine and potential reasons for its efficacy in animal models of sepsis, and its inefficacy in ameliorating oxidative stress-induced organ dysfunction in human sepsis. Finally, we review the pre-clinical studies examining the antioxidant and pleiotropic actions of vitamin C that may be of benefit for mitigating septic AKI, including future implications for clinical sepsis.

Cul4a ublažava LPS-indukovanu akutnu insuficijenciju bubrega blokiranjem NF-kB signalnog puta u slučaju sepse

BackgroundAcute kidney injury (AKI) is a common disease that can develop into end-stage kidney disease. Sepsis is one of the main causes of AKI. Currently, there is no satisfactory way to treat septic AKI. Therefore, we have shown the protective function of Cul4a in septic AKI and its molecular mechanism.MethodsThe cellular and animal models of septic AKI were established by using lipopolysaccharide (LPS). Western blot (WB) was employed to analyze Cul4a expression. RT-qPCR was employed to test the expression of Cul4a, SOD1, SOD2, GPX1, CAT, IL-6, TNF-a, Bcl-2, IL1b, Bax and KIM-1 mRNA. ELISA was performed to detect the contents of inflammatory factors and LDH. CCK-8 was utilized to detect cell viability. Flow cytometry was utilized to analyze the apoptosis. DHE-ROS kit was used to detect the content of ROS.ResultsCul4a was down-regulated in cellular and animal models of septic AKI. Oxidative stress is obviously induced by LPS, as well as apoptosis and inflammation. However, these can be significantly inhibited by up-regulating Cul4a. Moreover, LPS induced the activation of the NF-kB pathway, which could also be inhibited by overexpression of Cul4a.ConclusionsCul4awas found to be a protective factor in septic AKI, which could inhibit LPS-induced oxidative stress, apoptosis and inflammation of HK-2 cells by inhibiting the NF-kB pathway.

MicroRNA-214-5p aggravates sepsis-related acute kidney injury in mice.

Acute kidney injury (AKI) is a devastating comorbidity in sepsis and correlates with a very poor prognosis and increased mortality. Currently, we use lipopolysaccharide (LPS) to establish sepsis-related AKI and try to demonstrate the pathophysiological role of microRNA-214-5p (miR-214-5p) in this process. Mice were intravenously injected with the miR-214-5p agomir, antagomir or negative controls for three consecutive days and then received a single intraperitoneal injection of LPS (10mg/kg) for 24 h to induce AKI. Besides, the Boston University mouse proximal tubular cell lines were stimulated with LPS (10μg/ml) for 8h to investigate the role of miR-214-5p in vitro. To inhibit adenosine monophosphate-activated protein kinase (AMPK), compound C (CpC) was used in vivo. For glucagon-like peptide-1 receptor (GLP-1R) silence, cells were transfected with the small interfering RNA against GLP-1R. miR-214-5p level was upregulated in LPS-treated kidneys and proximal tubular cell lines. The miR-214-5p antagomir reduced LPS-induced renal inflammation and oxidative stress, thereby preventing renal damage and dysfunction. In contrast, the miR-214-5p agomir aggravated LPS-induced inflammation, oxidative stress and AKI in vivo and in vitro. Mechanistically, we found that the miR-214-5p antagomir prevented septic AKI via activating AMPK and that CpC treatment completely abrogated its renoprotective effect in mice. Further detection showed that miR-214-5p directly bound to the 3'-untranslational region of GLP-1R to inhibit GLP-1R/AMPK axis. Our data identify miR-214-5p as a promising therapeutic candidate to treat sepsis-related AKI.

ROCK1 regulates sepsis-induced acute kidney injury via TLR2-mediated endoplasmic reticulum stress/pyroptosis axis

BackgroundIt has been reported that ROCK1 participates in the progression of multiple diseases, including septic intestinal barrier, cardiac dysfunction and acute lung injury. However, its regulatory role and specific mechanism in sepsis-induced acute kidney injury (AKI) remain unclear. MethodsCecal ligation puncture (CLP) was conducted to establish sepsis mouse model, and in vitro model was achieved by lipopolysaccharide (LPS) stimulation. Genes expression was evaluated by qRT-PCR, western blot or ELISA was conducted to assess the levels of proteins. Hoechst staining was performed to evaluate cell pyroptosis. LDH activity assay was detected to assess cytotoxicity. Immunohistochemistry was conducted to detect Ly-6G expression and neutrophils distribution in kidney tissues of mice. H&E and TUNEL staining were carried to evaluate kidney injury of mice. ResultsOur findings illuminated that ROCK1 was highly expressed in sepsis-induced AKI, and ROCK1 knockdown inhibited NLRP3-mediated cell pyroptosis in LPS-induced HK-2 cells. Moreover, ROCK1 modulated HK-2 cell pyroptosis by regulating endoplasmic reticulum stress (ERS). TLR2 inhibitor could suppress ERS mediated cell pyroptosis under LPS treatment. Further, TLR2 activator partially reversed the effects of ROCK1 inhibition on ERS mediated pyroptosis in LPS-treated HK-2 cells and CLP mice. ConclusionIn conclusion, ROCK1 may regulate sepsis-induced AKI via TLR2-mediated ERS/pyroptosis axis. Our data demonstrated the role and underlying mechanism of ROCK1 in septic AKI, providing theoretical basis for sepsis-induced AKI treatment.

Upregulation of lncRNA NONRATG019935.2 suppresses the p53-mediated apoptosis of renal tubular epithelial cells in septic acute kidney injury

Although increasing evidence has confirmed that the apoptosis of renal tubular epithelial cells (RTECs) is a crucial contributor to the onset and development of septic acute kidney injury (AKI), the pathological mechanism by which RTEC apoptosis is upregulated during septic AKI is not entirely clear. In this study, a rat model of septic AKI was induced by a cecal ligation puncture procedure or lipopolysaccharide (LPS) injection. Four differentially expressed long noncoding RNAs (DE-Lncs) in the rat model of septic AKI were determined using RNA-sequencing and verified by qRT-PCR. Among the four DE-Lncs, the expression level of lncRNA NONRATG019935.2 (9935) exhibited the most significant reduction in both septic AKI rats and LPS-treated NRK-52E cells (a rat RTEC line). The overexpression of 9935 suppressed cell apoptosis and p53 protein level in LPS-treated NRK-52E cells, and retarded septic AKI development in the rat model of septic AKI. Mechanistically, 9935 decreased the human antigen R (HuR)-mediated Tp53 mRNA stability by limiting the combination of HuR and the 3′UTR region of Tp53 mRNA in RTECs. The overexpression of HuR abrogated the inhibitory effect of pcDNA-9935 on the LPS-induced apoptosis of NRK-52E and rat primary RTECs. In conclusion, 9935 exerts its role in septic AKI by suppressing the p53-mediated apoptosis of RTECs, and this essential role of 9935 relies on its destructive effect on HuR-mediated Tp53 mRNA stability.

MiR-150-5p protects against septic acute kidney injury via repressing the MEKK3/JNK pathway

BackgroundSeptic acute kidney injury (AKI) is associated with increased morbidity and mortality in critically ill patients. MicroRNA is reportedly involved in sepsis-induced organ dysfunction, while the role of miR-150 in septic AKI remains ambiguous. MethodsQuantitative real-time PCR (qRT-PCR) was carried out to examine miR-150-5p expression in both septic AKI patients and volunteers without septic AKI. Lipopolysaccharide (LPS) was used to treat renal tubular epithelial cell line HK-2 and C57/BL6 mice to establish in vitro and in vivo sepsis-induced AKI models. Cell apoptosis was determined using TdT-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry. Cell viability was tested using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Renal pathological changes were examined via Hematoxylin-Eosin (H&E) staining, and renal function was measured via blood urea nitrogen (BUN) and creatinine (Cre) measurements. The MEKK3/JNK profile and oxidative stress markers (including COX2 and iNOS) were examined by immunoblot analysis, and the expression levels of inflammatory cytokines (TNF-α, IL-6, and IL-1β) and oxidative stress markers (MDA, SOD, and CAT) were evaluated by ELISA. ResultsMiR-150-5p was down-regulated in the serum of patients with septic AKI (compared to healthy volunteers). Moreover, miR-150-5p levels were lower in LPS-treated HK-2 cell lines and in the septic AKI mouse model. Additionally, Stat-3 activation mediated the decrease of miR-150-5p. Functionally, miR-150-5p agomir attenuated LPS-induced apoptosis in HK-2 cells, in addition to renal inflammatory responses and oxidative stress. In contrast, inhibition of miR-150-5p aggravated LPS-induced apoptosis, inflammatory reactions and oxidative stress. Furthermore, miR-150-5p agomir decreased BUN and Scr levels in the septic AKI mice model repressed TNF-α, IL-6 and IL-1β, and up-regulated SOD and CAT down-regulated MDA in the kidney tissues. Moreover, miR-150-5p was identified as a target gene for Stat3, and the overexpression of Stat3 partially promoted the effect of down-regulating miR-150-5p on LPS-induced HK2 cell injury. Mechanistically, the MEKK3/JNK pathway was identified as a functional target of miR-150-5p, and the knockdown of MEKK3 showed protective effects against LPS mediated HK-2 cell apoptosis. ConclusionStat3-mediated miR-150-5p exerted protective effects in sepsis-induced acute kidney injury by regulating the MEKK3/JNK pathway.

Urinary actin, as a potential marker of sepsis-related acute kidney injury: A pilot study.

A major complication of sepsis is the development of acute kidney injury (AKI). Recently, it was shown that intracellular actin released from damaged tissues appears in the urine of patients with multiple organ dysfunction syndrome. Our aims were to measure urinary actin (u-actin) concentrations of septic and control patients and to test if u-actin levels could predict AKI and mortality. Blood and urine samples were collected from septic and sepsis-related AKI patients at three time points (T1-3): T1: within 24 hours after admission; T2: second day morning; T3: third day morning of follow-up. Patients with malignancies needing palliative care, end-stage renal disease or kidney transplantation were excluded. Serum and u-actin levels were determined by quantitative Western blot. Patients were categorized by the Sepsis-3 and KDIGO AKI classifications. In our study, 17 septic, 43 sepsis-induced AKI and 24 control patients were enrolled. U-actin levels were higher in septic patients compared with controls during follow-up (p<0.001). At T1, the septic and sepsis-related AKI groups also showed differences (p<0.001), yet this increase was not statistically significant at T2 and T3. We also detected significantly elevated u-actin concentrations in AKI-2 and AKI-3 septic patients compared with AKI-1 septic patients (p<0.05) at T1 and T3, along with a significant increase in AKI-2 septic patients compared with AKI-1 septic patients at T2 (p<0.01). This tendency remained the same when referring u-actin to urine creatinine. Parameters of first-day septic patient samples could discriminate AKI from non-AKI state (AUC ROC, p<0.001): u-actin: 0.876; se-creatinine: 0.875. Derived cut-off value for u-actin was 2.63 μg/L (sensitivity: 86.0%, specificity: 82.4%). U-actin may be a complementary diagnostic biomarker to se-creatinine in sepsis-related AKI while higher u-actin levels also seem to reflect the severity of AKI. Further investigations may elucidate the importance of u-actin release in sepsis-related AKI.

MicroRNA‑93 inhibits the apoptosis and inflammatory response of tubular epithelial cells via the PTEN/AKT/mTOR pathway in acute kidney injury.

Renal tubular epithelial cell injury is the main cause of septic acute kidney injury (AKI), which is characterized by the excessive inflammatory response and apoptosis. Numerous studies have demonstrated that miRNAs are associated with inflammatory response and apoptosis in numerous diseases. The present study mainly focuses on investigating the association between microRNA (miRNA/miR) expression and inflammatory response and apoptosis in the pathogenesis of AKI. In vitro and in vivo models of AKI were simulated using Escherichia coli lipopolysaccharide (LPS)-administrated kidney epithelial cells and mice, respectively. The miRNA expression profile was examined using miRNA microarray in kidney tissues. Next, the effects of miR-93 upregulation on the apoptosis, cytokine expression and oxidative stress in the LPS-stimulated TCMK-1 were tested. The target genes of this miRNA were investigated, and the regulatory association between miR-93 and the AKT/mTOR pathway was investigated. The results demonstrated that miR-93 was the most downregulated miRNA in mice kidney. Furthermore, in LPS-induced renal tubular epithelial cells (TECs) injury model, that upregulation of miR-93 was found to attenuate the apoptosis and inflammatory response, as well as reactive oxygen species generation. Mechanistically, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was identified as a target of miR-93. Further experiments revealed that LPS-induced the decrease of phosphorylated (p)-AKT and p-mTOR protein expression in vitro are reversed by the overexpression of miR-93. The results of the present study suggested that the protective effect of miR-93 on AKI may be associated with the activation of PTEN/AKT/mTOR pathway. miR-93 may serve as a potential therapeutic target in sepsis-induced AKI.