Sepsis-associated Acute Kidney Injury Research Articles

Discovery and verification of mmu_Circ_26986/hsa_Circ_0072463 as a potential biomarker and intervention target for sepsis-associated acute kidney injury

Approximately 60% of septic patients developed acute kidney injury (AKI). The mortality rate of septic AKI (SA-AKI) is two to three times higher than that of septic without AKI (SA-non-AKI). The actual functions and mechanisms of CircRNAs in the pathophysiology of SA-AKI remain incompletely understood. Herein, we observed that the mmu_Circ_26986 could be induced by lipopolysaccharide (LPS) and cecum ligation and puncture (CLP) in BUMPT cell line and C57BL/6 mouse kidney, respectively. Functionally, mmu_Circ_26986 suppressed BUMPT cell apoptosis induced by LPS. Mechanistically, mmu_Circ_26986 sponged miRNA-29b-1-5p to upregulate the expression of PAK7. Overexpression of mmu_Circ_26986 ameliorated the progression of CLP-stimulated AKI through miRNA-29b-1-5p/PAK7 axis. In addition, we found that hsa_Circ_0072463, homologous to mmu_Circ_26986, suppressed LPS-induced HK-2 cells apoptosis via regulation of miRNA-29b-1-5p/PAK7 axis. Furthermore, sepsis patients with AKI had a higher level of hsa_Circ_0072463 compared to those without AKI. The sensitivity, specificity and AUC of hsa_Circ_0072463 were 78.8%, 87.9% and 0.866, respectively. Spearman's test indicated a noticeable positive correlation between plasma hsa_Circ_0072463 and serum creatinine in sepsis patients (r = 0.725). In summary, this study reveals that the mmu_Circ_26986/hsa_Circ_0072463 miRNA-29b-1-5p/PAK7 axis mediates septic AKI, and hsa_Circ_0072463 is a potential diagnostic marker for septic AKI.

Serum phosphate levels and the development of sepsis associated acute kidney injury: evidence from two independent databases.

We aimed to investigate the association between serum phosphate levels and the risk for developing sepsis associated acute kidney injury (SAKI). Septic patients from the Medical Information Mart for Intensive Care IV (MIMIC IV) and the eICU Collaborative Research Database (eICU-CRD) were enrolled. Restricted cubic spline (RCS) was used to visualize the relationship between phosphate levels and the risk of SAKI. Patients were divided into four categories based on their serum phosphate levels. Logistic regression analysis, receiver operating characteristic (ROC) curve and subgroup analysis were performed to evaluate the predictive value of serum phosphate for SAKI. A total of 9,244 and 2,124 patients from the MIMIC IV and eICU-CRD database were included in the final analysis. RCS curve revealed a non-linear correlation between phosphate levels and the risk of SAKI (p for non-linearity <0.05). Each 1 mg/dL increase in phosphate levels was associated with a 1.51 to 1.64-fold increased risk of SAKI (OR 2.51-2.64, p < 0.001) in the MIMIC IV cohort and a 0.29 to 0.38-fold increased risk (OR 1.29-1.38, p < 0.001) in the eICU-CRD cohort. Compared to the normal-low category, hyperphosphatemia and normal-high category were independently associated with an increased risk of SAKI, while hypophosphatemia was independently associated with a decreased risk in the MIMIC IV cohort. A similar trend was observed in the eICU-CRD cohort, but statistical significance disappeared in the hypophosphatemia category and the adjusted model of normal high category. These finding was consistent in subgroup analysis. Elevated serum phosphate, even within the normal range, is an independent risk factor for developing SAKI in septic patients. Abnormal change in serum phosphate levels may be a novel biomarker for early prediction of SAKI occurrence.

TIMP2 protects against sepsis-associated acute kidney injury by cAMP/NLRP3 axis-mediated pyroptosis.

The tissue inhibitor of metalloproteinases 2 (TIMP2) has emerged as a promising biomarker for predicting the risk of sepsis-associated acute kidney injury (SA-AKI). However, its exact role in SA-AKI and the underlying mechanism remains unclear. In this study, we investigated the impact of kidney tubule-specific Timp2 knockout mice on kidney injury and inflammation. Our findings demonstrated that Timp2-knockout mice exhibited more severe kidney injury than wild-type mice, along with elevated levels of pyroptosis markers NOD-like receptor protein 3 (NLRP3), Caspase1, and gasdermin D (GSDMD) in the early stage of SA-AKI. Conversely, the expression of exogenous TIMP2 in TIMP2-knockout mice still protected against kidney damage and inflammation. In in vitro experiments, using recombinant TIMP2 protein, TIMP2 knockdown demonstrated that exogenous TIMP2 inhibited pyroptosis of renal tubular cells stimulated by lipopolysaccharide (LPS). Mechanistically, TIMP2 promoted the ubiquitination and autophagy-dependent degradation of NLRP3 by increasing intracellular cyclic adenosine monophosphate (cAMP), which mediated NLRP3 degradation through recruiting the E3 ligase MARCH7, attenuating downstream pyroptosis, and thus alleviating primary tubular cell damage. These results revealed the renoprotective role of extracellular TIMP2 in SA-AKI by attenuating tubular pyroptosis, and suggested that exogenous administration of TIMP2 could be a promising therapeutic intervention for SA-AKI treatment.NEW & NOTEWORTHY Tissue inhibitor of metalloproteinase 2 (TIMP-2) has been found to be the best biomarker for predicting the risk of sepsis-associated acute kidney injury (SA-AKI). However, its role and the underlying mechanism in SA-AKI remain elusive. The authors demonstrated in this study using kidney tubule-specific knockout mice model of SA-AKI and primary renal tubule cells stimulated with lipopolysaccharide (LPS) that extracellular TIMP-2 promoted NOD-like receptor protein 3 (NLRP3) ubiquitination and autophagy-dependent degradation by increasing intracellular cyclic adenosine monophosphate (cAMP), thus attenuated pyroptosis and alleviated renal damage.

Uplift modeling to predict individual treatment effects of renal replacement therapy in sepsis-associated acute kidney injury patients

Renal replacement therapy (RRT) is a crucial treatment for sepsis-associated acute kidney injury (S-AKI), but it is uncertain which S-AKI patients should receive immediate RRT. Identifying the characteristics of patients who may benefit the most from RRT is an important task. This retrospective study utilized a public database and enrolled S-AKI patients, who were divided into RRT and non-RRT groups. Uplift modeling was used to estimate the individual treatment effect (ITE) of RRT. The validity of different models was compared using a qini curve. After labeling the patients in the validation cohort, we characterized the patients who would benefit the most from RRT and created a nomogram. A total of 8289 patients were assessed, among whom 591 received RRT, and 7698 did not receive RRT. The RRT group had a higher severity of illness than the non-RRT group, with a Sequential Organ Failure Assessment (SOFA) score of 9 (IQR 6,11) vs. 5 (IQR 3,7). The 28-day mortality rate was higher in the RRT group than the non-RRT group (34.83% vs. 14.61%, p < 0.0001). Propensity score matching (PSM) was used to balance baseline characteristics, 458 RRT patients and an equal number of non-RRT patients were enrolled for further research. After PSM, 28-day mortality of RRT and non-RRT groups were 32.3% vs. 39.3%, P = 0.033. Using uplift modeling, we found that urine output, fluid input, mean blood pressure, body temperature, and lactate were the top 5 factors that had the most influence on RRT effect. The area under the uplift curve (AUUC) of the class transformation model was 0.068, the AUUC of SOFA was 0.018, and the AUUC of Kdigo-stage was 0.050. The class transformation model was more efficient in predicting individual treatment effect. A logistic regression model was developed, and a nomogram was drawn to predict whether an S-AKI patient can benefit from RRT. Six factors were taken into account (urine output, creatinine, lactate, white blood cell count, glucose, respiratory rate). Uplift modeling can better predict the ITE of RRT on S-AKI patients than conventional score systems such as Kdigo and SOFA. We also found that white blood cell count is related to the benefits of RRT, suggesting that changes in inflammation levels may be associated with the effects of RRT on S-AKI patients.

Sepsis-Associated Acute Kidney Injury: Where Are We Now?

Worldwide, sepsis is a well-recognized cause of death. Acute kidney injury (AKI) may be related to sepsis in up to 70% of AKI cases. Sepsis-associated AKI (SA-AKI) is defined as the presence of AKI according to the Kidney Disease: Improving Global Outcomes criteria in the context of sepsis. SA-AKI is categorized into early, which presents during the first 48 h of sepsis, and late, presenting between 48 h and 7 days of sepsis. SA-AKI is associated with a worse prognosis among patients with sepsis. However, there are different SA-AKI phenotypes as well as different pathophysiological pathways of SA-AKI. The aim of this review is to provide an updated synopsis of the pathogenetic mechanisms underlying the development of SA-AKI as well as to analyze its different phenotypes and prognosis. In addition, potential novel diagnostic and prognostic biomarkers as well as therapeutic approaches are discussed. A plethora of mechanisms are implicated in the pathogenesis of SA-AKI, including inflammation and metabolic reprogramming during sepsis; various types of cell death such as apoptosis, necroptosis, pyroptosis and ferroptosis; autophagy and efferocytosis; and hemodynamic changes (macrovascular and microvascular dysfunction). Apart from urine output and serum creatinine levels, which have been incorporated in the definition of AKI, several serum and urinary diagnostic and prognostic biomarkers have also been developed, comprising, among others, interleukins 6, 8 and 18, osteoprotegerin, galectin-3, presepsin, cystatin C, NGAL, proenkephalin A, CCL-14, TIMP-2 and L-FABP as well as biomarkers stemming from multi-omics technologies and machine learning algorithms. Interestingly, the presence of long non-coding RNAs (lncRNAs) as well as microRNAs (miRNAs), such as PlncRNA-1, miR-22-3p, miR-526b, LncRNA NKILA, miR-140-5p and miR-214, which are implicated in the pathogenesis of SA-AKI, may also serve as potential therapeutic targets. The combination of omics technologies represents an innovative holistic approach toward providing a more integrated view of the molecular and physiological events underlying SA-AKI as well as for deciphering unique and specific phenotypes. Although more evidence is still necessary, it is expected that the incorporation of integrative omics may be useful not only for the early diagnosis and risk prognosis of SA-AKI, but also for the development of potential therapeutic targets that could revolutionize the management of SA-AKI in a personalized manner.

MiR-16-5p aggravates sepsis-associated acute kidney injury by inducing apoptosis

Sepsis-associated acute kidney injury (S-AKI) is a common disease in pediatric intensive care units (ICU) with high morbidity and mortality. The newly discovered results indicate that microRNAs (miRNAs) play an important role in the diagnosis and treatment of S-AKI and can be used as markers for early diagnosis. In this study, the expression level of miR-16-5p was found to be significantly upregulated about 20-fold in S-AKI patients, and it also increased by 1.9 times in the renal tissue of S-AKI mice. Receiver operating characteristic (ROC) curve analysis showed that miR-16-5p had the highest predictive accuracy in the diagnosis of S-AKI (AUC = 0.9188). In vitro, the expression level of miR-16-5p in HK-2 cells treated with 10 μg/mL lipopolysaccharide (LPS) increased by more than 2 times. In addition, LPS-exposed renal tissue and HK-2 cells lead to upregulation of inflammatory cytokines IL-6, IL-1β, TNF-a, and kidney damage molecules kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL). However, inhibition of miR-16-5p significantly mitigated LPS expose-mediated kidney injury and inflammation. Furthermore, LPS-exposed HK-2 cells increased more than 1.7-fold the expression levels of Bax and caspase-3, decreased 3.2-fold the expression level of B-cell lymphoma-2 (Bcl-2), and significantly promoted the occurrence of apoptosis. MiR-16-5p mimic further increased LPS-induced apoptosis in HK-2 cells. Nevertheless, inhibition of miR-16-5p significantly attenuated this effect. In summary, up-regulation of miR-16-5p expression can significantly aggravate renal injury and apoptosis in S-AKI, which also proves that miR-16-5p can be used as a potential biomarker to promote early identification of S-AKI.

The combination of kidney function variables with cell cycle arrest biomarkers identifies distinct subphenotypes of sepsis-associated acute kidney injury: a post-hoc analysis (the PHENAKI study)

Background The severity and course of sepsis-associated acute kidney injury (SA-AKI) are correlated with the mortality rate. Early detection of SA-AKI subphenotypes might facilitate the rapid provision of individualized care. Patients and methods In this post-hoc analysis of a multicenter prospective study, we combined conventional kidney function variables with serial measurements of urine (tissue inhibitor of metalloproteinase-2 [TIMP-2])* (insulin-like growth factor-binding protein [IGFBP7]) at 0, 6, 12, and 24 h) and then using an unsupervised hierarchical clustering of principal components (HCPC) approach to identify different phenotypes of SA-AKI. We then compared the subphenotypes with regard to a composite outcome of in-hospital death or the initiation of renal replacement therapy (RRT). Results We included 184 patients presenting SA-AKI within 6 h of the initiation of catecholamines. Three distinct subphenotypes were identified: subphenotype A (99 patients) was characterized by a normal urine output (UO), a low SCr and a low [TIMP-2]*[IGFBP7] level; subphenotype B (74 patients) was characterized by existing chronic kidney disease (CKD), a higher SCr, a low UO, and an intermediate [TIMP-2]*[IGFBP7] level; and subphenotype C was characterized by very low UO, a very high [TIMP-2]*[IGFBP7] level, and an intermediate SCr level. With subphenotype A as the reference, the adjusted hazard ratio (aHR) [95%CI] for the composite outcome was 3.77 [1.92–7.42] (p < 0.001) for subphenotype B and 4.80 [1.67–13.82] (p = 0.004) for subphenotype C. Conclusions Combining conventional kidney function variables with urine measurements of [TIMP-2]*[IGFBP7] might help to identify distinct SA-AKI subphenotypes with different short-term courses and survival rates.

Renal arterial resistive index versus novel biomarkers for the early prediction of sepsis-associated acute kidney injury

Acute kidney injury (AKI) is a critical complication of sepsis. There is a continuous need to identify and validate biomarkers for early detection. Serum and urinary biomarkers have been investigated, such as neutrophil gelatinase associated lipocalin (NGAL) and cystatin C (Cys C), but their reliability in the intensive care unit (ICU) remains unknown. Renal hemodynamics can be investigated by measuring the renal resistive index (RRI). This study aimed to compare the performance of RRI, serum NGAL (sNGAL), urinary NGAL (uNGAL), and serum Cys C levels as early predictors of the diagnosis and persistence of sepsis-associated AKI. A total of 166 adult patients with sepsis syndrome were enrolled immediately after ICU admission. Biomarkers were measured directly (T1) and on day 3 (T3). RRI was measured directly (T1) and 24 h later (T2). Patients were categorized (according to the occurrence and persistence of AKI within the first 7 days) into three groups: no AKI, transient AKI, and persistent AKI. The incidence rate of sepsis-associated AKI was 60.2%. Sixty-six patients were categorized as in the no AKI group, while another 61 were in transient AKI and only 39 were in persistent AKI. The RRI value (T1 ≥ 0.72) was the best tool for predicting AKI diagnosis (area under the receiver operating characteristic curve, AUROC = 0.905). Cys C (T1 ≥ 15.1 mg/l) was the best tool to predict the persistence of AKI (AUROC = 0.977). RRI (T1) was the best predictive tool for sepsis-associated AKI, while Cys C was the best predictor of its persistence and 28-day mortality.

LncRNA NORAD alleviates dysfunction of renal proximal tubular epithelial cells during the sepsis-associated acute kidney injury by modulating the miR-155-5p-PDK1 axis.

The sepsis-associated acute kidney injury (Sa-AKI) is closely related to high mortality rates worldwide. Injury to the renal proximal tubular epithelial cells (RPTECs), caused by pathological conditions, is a major cause of acute kidney injury (AKI). The lncRNA NORAD has been reported to be positively associated with kidney cancers. However, the biological roles and underlying mechanisms of NORAD in RPTECs during AKI are still unclear. In this study, we found that NORAD was significantly downregulated in RPTECs from AKI tissues. Overexpression of NORAD alleviated RPTECs injury induced by lipopolysaccharide (LPS). Additionally, glucose metabolism was significantly impaired during AKI, and LPS treatment inhibited glucose metabolism in RPTECs. We demonstrated that NORAD rescued the LPS-induced inhibition of glucose metabolism in RPTECs. Furthermore, miRNA-155-5p was significantly upregulated in RPTECs from AKI. Through bioinformatics analysis, RNA pull-down, RNA IP, and luciferase assays, we showed that NORAD directly associated with miR-155-5p to downregulate its expression. Moreover, overexpression of miR-155-5p inhibited glucose metabolism by directly targeting the 3'UTR of the glucose metabolism enzyme, pyruvate dehydrogenase kinase 1 (PDK1). Finally, rescue experiments validated that NORAD's protective effect on RPTECs injury was mediated through modulation of the miR-155-5p-PDK1-glucose metabolism pathway. In summary, these results reveal that lncRNA NORAD can alleviate RPTECs dysfunction by targeting the miR-155-5p-PDK1 axis, suggesting that NORAD has the potential to contribute to the development of therapeutic approaches against Sa-AKI.

Andrographolide attenuates sepsis-induced acute kidney injury by inhibiting ferroptosis through the Nrf2/FSP1 pathway

Sepsis is a systemic inflammatory response syndrome caused by infection, which causes renal dysfunction known as sepsis-associated acute kidney injury (S-AKI). Ferroptosis is a form of lipid peroxidation dependent on iron and reactive oxygen species that differs from other forms of programmed cell death at the morphological and biochemical levels. Andrographolide (AG), a natural diterpenoid lactone compound extracted from Andrographis paniculata, has been shown to have therapeutic effects in kidney disease. In this study, we investigated the novel mechanism by which AG attenuates septic acute kidney injury by inhibiting ferroptosis in renal tubular epithelial cells (HK-2) through the Nrf2/FSP1 pathway. Cecum ligation and puncture (CLP)-induced septic rats and lipopolysaccharide (LPS)-induced HK-2 cells were used for in vivo and in vitro experiments. Firstly, in septic rats and HK-2 cells, AG effectively decreased the levels of kidney injury indicators, including blood creatinine, urea nitrogen, and markers of kidney injury such as neutrophil gelatinase-associated lipid transport protein and kidney injury molecule-1 (KIM-1). In addition, AG prevented ferroptotosis, by avoiding the accumulation of iron and lipid peroxidation, and an increase in SLC7A11 and GPX4 in AG-treated HK-2 cells. Furthermore, AG attenuated mitochondrial damage, including mitochondrial swelling, outer membrane rupture, and a reduction in mitochondrial cristae in LPS-treated HK-2 cells. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, significantly inhibited LPS-induced ferroptosis in HK-2 cells. Importantly, our results confirm that Nrf2/FSP1 is an important pathway for ferroptosis resistance. Nrf2 siRNA hindered the effect of AG in attenuating acute kidney injury and inhibiting ferroptosis. These findings demonstrate that Nrf2/FSP1-mediated HK-2 ferroptosis is associated with AG, alleviates septic acute kidney injury, and indicates a novel avenue for therapeutic interventions in the treatment of acute kidney injury in sepsis.

Comparison of diagnostic criteria for sepsis-associated acute kidney injury in the pediatric intensive care unit: a retrospective cohort study.

pRIFLE (Pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease), KDIGO (Kidney Disease Improving Global Outcomes) and pROCK (Pediatric Reference Change Value Optimized for AKI) are diagnostic criteria used for acute kidney injury (AKI) incidence evaluation. The aim of this study was to explore the diagnostic consistency, incidence and mortality rate, clinical signs, and influencing factors of renal injury related to sepsis in children diagnosed by three different AKI diagnostic criteria, and then evaluate which one was more valuable. A retrospective analysis was performed on the clinical data of children with severe sepsis. The patients were diagnosed and staged according to the 2007 pRIFLE standard, the 2012 KDIGO standard, and the 2018 pROCK standard. The clinical characteristics and prognosis of children with different stages of sepsis were compared between the three diagnostic standards. A total of 62 patients with sepsis were included. Blood stream infection is common (11 cases, 17.74%). According to pRIFLE, KDIGO, and pROCK standards, the incidence of sepsis-associated AKI (SA-AKI) was 74.2%, 67.7%, and 56.5%, respectively. The pRIFLE had the highest diagnostic rate of early detection of SA-AKI. There was no statistical difference in SA-AKI incidence or staging consistency between the pRIFLE and KDIGO groups (κ=0.0671; κ>0.60); the consistency of SA-AKI diagnoses across the three standards was good (all P values <0.05), and pROCK demonstrated a higher specificity. A high Pediatric Risk of Mortality (PRISM) score and high procalcitonin level were independent risk factors. Shock and renal replacement therapy were independent risk factors for SA-AKI death. Death from admission to 28 days after admission was used as an endpoint to draw a survival graph, which revealed that the AKI group had a significantly higher risk of death than did the non-AKI group. The consistency of diagnosing SA-AKI across the three classification criteria was similar, and mortality rate increased with increased SA-AKI staging. The pRIFLE criteria were more sensitive in the early detection of SA-AKI, while the pROCK had higher specificity. There was no significant difference between the pRIFLE and KDIGO in terms of incidence, diagnosis, or staging of SA-AKI.

Tubule dysfunction and injury and future risk of sepsis-associated acute kidney injury.

Novel biomarkers can quantify both kidney tubule function, including proximal tubule reabsorptive (urine α-1 microglobulin (uα1m)) and tubule protein synthesis capacities (urine uromodulin (uUMOD)), and tubular injury (urine neutrophil gelatinase-associated lipocalin (uNGAL)). In a blood pressure trial, we reported that lower reabsorptive and synthetic protein capacity at times of health predicted future risk of acute kidney injury (AKI), but most AKI was related to hemodynamic causes in this trial. Associations between tubular function and injury and future AKI related to other causes is unknown. We performed a case-control study in REGARDS, a population-based cohort study, among participants who provided urine at the baseline visit. We matched each septic AKI case by age, sex, race, and time from baseline to hospital admission 1:1 to a participant with sepsis who did not develop AKI (controls). Using conditional logistic regression, we evaluated the associations of uα1m, uUMOD, urine ammonium, and uNGAL with septic AKI. Mean age was 69 ± 8 years, 44% were female, and 39% were Black participants. Median baseline eGFR among cases and controls was 73 (55, 90) and 82 (65, 92) mL/min/1.73m2, and median albuminuria was 19 (8, 87) vs. 9 (5, 22) mg/g, respectively. No independent associations were observed between the tubule function or injury markers and subsequent risk of septic AKI once models were adjusted for baseline albuminuria, estimated glomerular filtration rate, and other risk factors. Among community participants, tubule function and injury markers at times of health were not independently associated with future risk of septic AKI.

The effect of renal replacement therapy on the concentration of tigecycline in the blood in patients with sepsis-associated acute kidney injury

The effect of renal replacement therapy on the concentration of tigecycline in the blood in patients with sepsis-associated acute kidney injury

Uromodulin in sepsis and severe pneumonia: a two-sample Mendelian randomization study.

The outcome for patients with sepsis-associated acute kidney injury in the intensive care unit (ICU) remains poor. Low serum uromodulin (sUMOD) protein levels have been proposed as a causal mediator of this effect. We investigated the effect of different levels of sUMOD on the risk of sepsis and severe pneumonia and outcomes in these conditions. A two-sample Mendelian randomization (MR) study was performed. Single-nucleotide polymorphisms (SNPs) associated with increased levels of sUMOD were identified and used as instrumental variables for association with outcomes. Data from different cohorts were combined based on disease severity and meta-analyzed. Five SNPs associated with increased sUMOD levels were identified and tested in six datasets from two biobanks. There was no protective effect of increased levels of sUMOD on the risk of sepsis [two cohorts, odds ratio (OR) 0.99 (95% confidence interval 0.95-1.03), P = 0.698, and OR 0.95 (0.91-1.00), P = 0.060, respectively], risk of sepsis requiring ICU admission [OR 1.04 (0.93-1.16), P = 0.467], ICU mortality in sepsis [OR 1.00 (0.74-1.37), P = 0.987], risk of pneumonia requiring ICU admission [OR 1.05 (0.98-1.14), P = 0.181], or ICU mortality in pneumonia [OR 1.17 (0.98-1.39), P = 0.079]. Meta-analysis of hospital-admitted and ICU-admitted patients separately yielded similar results [OR 0.98 (0.95-1.01), P = 0.23, and OR 1.05 (0.99-1.12), P = 0.86, respectively]. Among patients with sepsis and severe pneumonia, there was no protective effect of different levels of sUMOD. Results were consistent regardless of geographic origins and not modified by disease severity. NEW & NOTEWORTHY The presence of acute kidney injury in severe infections increases the likelihood of poor outcome severalfold. A decrease in serum uromodulin (sUMOD), synthetized in the kidney, has been proposed as a mediator of this effect. Using the Mendelian randomization technique, we tested the hypothesis that increased sUMOD is protective in severe infections. Analyses, however, showed no evidence of a protective effect of higher levels of sUMOD in sepsis or severe pneumonia.

Machine learning-based prediction of in-hospital mortality for critically ill patients with sepsis-associated acute kidney injury

Objectives This study aims to develop and validate a prediction model in-hospital mortality in critically ill patients with sepsis-associated acute kidney injury (SA-AKI) based on machine learning algorithms. Methods Patients who met the criteria for inclusion were identified in the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database and divided according to the validation (n = 2440) and development (n = 9756, 80%) queues. Ensemble stepwise feature selection method was used to screen for effective features. The prediction models of short-term mortality were developed by seven machine learning algorithms. Ten-fold cross-validation was used to verify the performance of the algorithm in the development queue. The area under the receiver operating characteristic curve (ROC-AUC) was used to evaluate the differentiation accuracy and performance of the prediction model in the validation queue. The best-performing model was interpreted by Shapley additive explanations (SHAP). Results A total of 12,196 patients were enrolled in this study. Eleven variables were finally chosen to develop the prediction model. The AUC of the random forest (RF) model was the highest value both in the Ten-fold cross-validation and evaluation (AUC: 0.798, 95% CI: 0.774–0.821). According to the SHAP plots, old age, low Glasgow Coma Scale (GCS) score, high AKI stage, reduced urine output, high Simplified Acute Physiology Score (SAPS II), high respiratory rate, low temperature, low absolute lymphocyte count, high creatinine level, dysnatremia, and low body mass index (BMI) increased the risk of poor prognosis. Conclusions The RF model developed in this study is a good predictor of in-hospital mortality for patients with SA-AKI in the intensive care unit (ICU), which may have potential applications in mortality prediction.

TAK-242 improves sepsis-associated acute kidney injury in rats by inhibiting the TLR4/NF-κB signaling pathway

Objective This study was designed to observe the effect of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway activity on sepsis-associated acute kidney injury (SA-AKI), thereby providing new considerations for the prevention and treatment of SA-AKI. Methods The rats were divided into Sham, cecal ligation and puncture (CLP), CLP + vehicle, and CLP + TAK-242 groups. Except the Sham group, a model of CLP-induced sepsis was established in other groups. After 24 h, the indicators related to kidney injury in blood samples were detected. The pathological changes in the kidneys were observed by hematoxylin-eosin staining, and tubular damage was scored. Oxidative stress-related factors, mitochondrial dysfunction-related indicators in each group were measured; the levels of inflammatory factors in serum and kidney tissue of rats were examined. Finally, the expression of proteins related to the TLR4/NF-κB signaling pathway was observed by western blot. Results Compared with the CLP + vehicle and CLP + TAK-242 groups, the CLP + TAK-242 group reduced blood urea nitrogen (BUN), creatinine (Cr), cystatin-C (Cys-C), reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory factors levels (p < 0.01), as well as increased superoxide dismutase (SOD) activity of CLP rats (p < 0.01). Additionally, TAK-242 treatment improved the condition of CLP rats that had glomerular and tubular injuries and mitochondrial disorders (p < 0.01). Further mechanism research revealed that TAK-242 can inhibit the TLR4/NF-κB signaling pathway activated by CLP (p < 0.01). Above indicators after TAK-242 treatment were close to those of the Sham group. Conclusion TAK-242 can improve oxidative stress, mitochondrial dysfunction, and inflammatory response by inhibiting the activity of TLR4/NF-κB signaling pathway, thereby preventing rats from SA-AKI.

Development and external validation of a nomogram for the early prediction of acute kidney injury in septic patients: a multicenter retrospective clinical study

Background and purpose: Acute kidney injury (AKI) is a common serious complication in sepsis patients with a high mortality rate. This study aimed to develop and validate a predictive model for sepsis associated acute kidney injury (SA-AKI). Methods: In our study, we retrospectively constructed a development cohort comprising 733 septic patients admitted to eight Grade-A tertiary hospitals in Shanghai from January 2021 to October 2022. Additionally, we established an external validation cohort consisting of 336 septic patients admitted to our hospital from January 2017 to December 2019. Risk predictors were selected by LASSO regression, and a corresponding nomogram was constructed. We evaluated the model’s discrimination, precision and clinical benefit through receiver operating characteristic (ROC) curves, calibration plots, decision curve analysis (DCA) and clinical impact curves (CIC) in both internal and external validation. Results: AKI incidence was 53.2% in the development cohort and 48.2% in the external validation cohort. The model included five independent indicators: chronic kidney disease stages 1 to 3, blood urea nitrogen, procalcitonin, D-dimer and creatine kinase isoenzyme. The AUC of the model in the development and validation cohorts was 0.914 (95% CI, 0.894–0.934) and 0.923 (95% CI, 0.895–0.952), respectively. The calibration plot, DCA, and CIC demonstrated the model’s favorable clinical applicability. Conclusion: We developed and validated a robust nomogram model, which might identify patients at risk of SA-AKI and promising for clinical applications.

Early Sepsis-Associated Acute Kidney Injury and Obesity.

The prevalence of obesity is increasing in the intensive care unit (ICU). Although obesity is a known risk factor for chronic kidney disease, its association with early sepsis-associated acute kidney injury (SA-AKI) and their combined association with patient outcomes warrant further investigation. To explore the association between obesity, early SA-AKI incidence, and clinical outcomes in patients with sepsis. This nationwide, prospective cohort study analyzed patients aged 19 years or older who had sepsis and were admitted to 20 tertiary hospital ICUs in Korea between September 1, 2019, and December 31, 2021. Patients with preexisting stage 3A to 5 chronic kidney disease and those with missing body mass index (BMI) values were excluded. Sepsis and hospitalization in the ICU. The primary outcome was SA-AKI incidence within 48 hours of ICU admission, and secondary outcomes were mortality and clinical recovery (survival to discharge within 30 days). Patients were categorized by BMI (calculated as weight in kilograms divided by height in meters squared), and data were analyzed by logistic regression adjusted for key characteristics and clinical factors. Multivariable fractional polynomial regression models and restricted cubic spline models were used to analyze the clinical outcomes with BMI as a continuous variable. Of the 4041 patients (median age, 73 years [IQR, 63-81 years]; 2349 [58.1%] male) included in the study, 1367 (33.8%) developed early SA-AKI. Obesity was associated with a higher incidence of SA-AKI compared with normal weight (adjusted odds ratio [AOR], 1.40; 95% CI, 1.15-1.70), as was every increase in BMI of 10 (OR, 1.75; 95% CI, 1.47-2.08). While obesity was associated with lower in-hospital mortality in patients without SA-AKI compared with their counterparts without obesity (ie, underweight, normal weight, overweight) (AOR, 0.72; 95% CI, 0.54-0.94), no difference in mortality was observed in those with SA-AKI (AOR, 0.85; 95% CI, 0.65-1.12). Although patients with obesity without SA-AKI had a greater likelihood of clinical recovery than their counterparts without obesity, clinical recovery was less likely among those with both obesity and SA-AKI. In this cohort study of patients with sepsis, obesity was associated with a higher risk of early SA-AKI and the presence of SA-AKI modified the association of obesity with clinical outcomes.

Maresin-1 Attenuates Sepsis-Associated Acute Kidney Injury via Suppressing Inflammation, Endoplasmic Reticulum Stress and Pyroptosis by Activating the AMPK/SIRT3 Pathway.

Sepsis-associated acute kidney injury (SA-AKI) is a common complication in patients with sepsis, triggering high morbidity and mortality. Maresin-1 (MaR1) is a pro-resolution lipid mediator that promotes the resolution of acute inflammation and protects organs from inflammation. In this study, we established an SA-AKI model using cecal ligation and puncture (CLP) and investigated the effect and mechanism of MaR1. The blood and kidneys were harvested 24 hours after surgery. The blood biochemical/routine indicators, renal function, SA-AKI-related pathophysiological processes, and AMPK/SIRT3 signaling in septic mice were observed by histological staining, immunohistochemical staining, Western blot, qPCR, ELISA and TUNEL Assay. MaR1 treatment alleviated kidney injury in septic mice, reflected in improved pathological changes in renal structure and renal function. MaR1 treatment decreased the levels of serum creatinine (sCr) and blood urea nitrogen (BUN) and the expressions of KIM-1, NGAL and TIMP-2, which were related to kidney injury, while inhibited the expressions of inflammatory factors TNF-α, IL-1β and IL-6. The expression of endoplasmic reticulum stress-related indicators p-PERK/PERK, GRP78, p-EIF2α/EIF2α, ATF4, CHOP, and pyroptosis-related indicators Caspase-1, NLRP3, GSDMD, IL-18, and IL-1β also decreased after MaR1 treatment. The mechanism may be related to the activation of the AMPK/SIRT3 signaling pathway, and an AMPK inhibitor (compound C) partially reverses MaR1's protective effects in septic mice. Taken together, these findings suggest that MaR1 may partially ameliorate SA-AKI by activating the AMPK/SIRT3 signaling pathway, providing a potential new perspective for research on SA-AKI.

633 - Notch signaling pathway mediates anti-inflammatory effects of vagus nerve stimulation during sepsis-associated acute kidney injury

633 - Notch signaling pathway mediates anti-inflammatory effects of vagus nerve stimulation during sepsis-associated acute kidney injury