Sepsis associated acute kidney injury

Medicinal evaluation and molecular docking study of osajin as an anti-inflammatory, antioxidant, and antiapoptotic agent against sepsis-associated acute kidney injury in rats

Despite efforts to find effective drugs for sepsis-associated acute kidney injury (SA-AKI), mortality rates in patients with SA-AKI have not decreased. Our study evaluated the protective effects of isoflavone osajin (OSJ) on SA-AKI in rats by targeting inflammation, oxidative stress, and apoptosis, which represent the cornerstones in the pathophysiological mechanism of SA-AKI. Polymicrobial sepsis was induced in rats via the cecal ligation and puncture (CLP) technique. Markers of oxidative stress were evaluated in kidney tissues using biochemical methods. The expression of interleukin-33 (IL-33), 8-hydroxydeoxyguanosine (8-OHdG), caspase-3, and kidney injury molecule-1 (KIM-1) was evaluated as indicators of inflammation, DNA damage, apoptosis, and SA-AKI respectively in the kidney tissues using immunohistochemical and immunofluorescent detection methods. The CLP technique significantly (p < 0.001) increased lipid peroxidation (LPO) levels and significantly (p < 0.001) decreased the activities of superoxide dismutase and catalase in kidney tissues. In the renal tissues, strong expression of IL-33, 8-OHdG, caspase-3, and KIM-1 was observed with severe degeneration and necrosis in the tubular epithelium and intense interstitial nephritis. In contrast, the administration of OSJ significantly (p < 0.001) reduced the level of LPO, markedly improved biomarkers of antioxidant status, decreased the levels of serum creatinine and urea, lowered the expression of IL-33, 8-OHdG, caspase-3, and KIM-1 and alleviated changes in renal histopathology. A promising binding score was found via a molecular docking investigation of the OSJ-binding mode with mouse IL-33 (PDB Code: 5VI4). Therefore, OSJ protects against SA-AKI by suppressing the IL-33/LPO/8-OHdG/caspase-3 pathway and improving the antioxidant system.

Risk factors and renal outcomes of AKI in children with secondary steroid-resistant nephrotic syndrome

BACKGROUND

Acute kidney injury (AKI) is increasingly prevalent in children with nephrotic syndrome (NS). It is associated with adverse outcomes in NS, especially steroid-resistant nephrotic syndrome (SRNS). The incidence, risk factors and outcomes of AKI in secondary SRNS remain undefined. The main objectives of this study were to determine the risk factors and prognosis of AKI in hospitalized children with secondary SRNS.

MATERIAL AND METHODS

This retrospective study was conducted from January 2014 to December 2019, involving 172 hospitalizations with secondary SRNS admitted to the First Affiliated Hospital of Sun Yat-sen University. AKI was defined and classified in accordance with the 2012 Kidney Disease Improving Global Outcomes (KDIGO) guidelines.

RESULTS

AKI was found in 67 (39.0%) of 172 hospitalizations with secondary SRNS. Average age of onset in our group is 4.4 (3.1, 6.7) years with AKI and 3.7 (1.8, 5.6) years without AKI. Urea nitrogen level is 5.9 (4.1, 10.0) mmol/L with AKI and 5.1 (3.7, 7.0) mmol/L. Uric acid level is 446.0 (340.0, 567.0) umol/L with AKI and 401.0 (303.0, 496.0) umol/L. 24-h urinary protein level is 4.14 (2.9, 6.5) g with AKI and 2.5 (1.3, 5.3) without AKI. Multivariate logistic regression revealed that infection (OR = 5.287; 95% confidence interval, 2.349 to 11.899; p < 0.001), age at onset (OR = 1.180; 95% confidence interval, 1.032 to 1.349; p = 0.015) and uric acid level (OR = 1.003; 95% confidence interval, 1.000 to 1.006; p = 0.031) were significantly associated with the development of AKI in children with secondary SRNS. Among 72 children with secondary SRNS, six went to end-stage kidney disease (ESKD). Children in the AKI group were more likely to progress to ESKD compared with children in the non-AKI group (p = 0.017) with a median follow-up of 48.5months.

CONCLUSION

AKI occurred in 39.0% of total hospitalizations associated with secondary SRNS. Risk factors including infection, age of onset, and uric acid level are associated with AKI in children with secondary SRNS. Furthermore, AKI was identified as a risk factor for the progression of secondary SRNS to ESKD.

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.

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.

Prognostic value of neutrophil-to-lymphocyte ratio dynamics in patients with septic acute kidney injury: a cohort study

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) has been suggested to be a prognostic marker for various diseases, but whether NLR dynamics (ΔNLR) is related to mortality and disease severity in patients with septic acute kidney injury (AKI) has not been determined.

METHODS

Between August 2013 and August 2021, septic AKI patients at our center were retrospectively enrolled. ΔNLR was defined as the difference between the NLR at septic AKI diagnosis and at hospital admission. The relationship between the ΔNLR and mortality was evaluated by Kaplan-Meier curves, Cox proportional hazards, and cubic spline analyses. The prediction values were compared by area under the receiver-operating characteristic curve (AUROC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses.

RESULTS

Of the 413 participants, the mean age was 63 ± 17 years, and 134 were female (32.4%). According to the median value, patients in the high-ΔNLR group had significantly greater 90-d mortality (74.4% vs. 46.6%, p < 0.001). After adjustment for potential confounders, high ΔNLR remained an independent predictor of 90-d mortality (HR = 2.80; 95% CI = 1.74-4.49, p < 0.001). Furthermore, ΔNLR had the highest AUROC for 90-d mortality (0.685) among the various biomarkers and exhibited an improved NRI (0.314) and IDI (0.027) when incorporated with PCT and CRP. For secondary outcomes, patients with high ΔNLR had increased risk of 30-d mortality (p = 0.004), need for renal replacement therapy (p = 0.011), and developing stage-3 AKI (p = 0.040) according to the adjusted models.

CONCLUSIONS

High ΔNLR is independently associated with increased risk of patient mortality and adverse outcomes. ΔNLR might be utilized to facilitate risk stratification and optimize septic AKI management.

Obeticholic acid ameliorates sepsis-induced renal mitochondrial damage by inhibiting the NF-κb signaling pathway

Acute kidney injury (AKI), a common complication of sepsis, might be caused by overactivated inflammation, mitochondrial damage, and oxidative stress. However, the mechanisms underlying sepsis-induced AKI (SAKI) have not been fully elucidated, and there is a lack of effective therapies for AKI. To this end, this study aimed to investigate whether obeticholic acid (OCA) has a renoprotective effect on SAKI and to explore its mechanism of action. Through bioinformatics analysis, our study confirmed that the mitochondria might be a critical target for the treatment of SAKI. Thus, a septic rat model was established by cecal ligation puncture (CLP) surgery. Our results showed an evoked inflammatory response via the NF-κB signaling pathway and NLRP3 inflammasome activation in septic rats, which led to mitochondrial damage and oxidative stress. OCA, an Farnesoid X Receptor (FXR) agonist, has shown anti-inflammatory effects in numerous studies. However, the effects of OCA on SAKI remain unclear. In this study, we revealed that pretreatment with OCA can inhibit the inflammatory response by reducing the synthesis of proinflammatory factors (such as IL-1β and NLRP3) via blocking NF-κB and alleviating mitochondrial damage and oxidative stress in the septic rat model. Overall, this study provides insight into the excessive inflammation-induced SAKI caused by mitochondrial damage and evidence for the potential use of OCA in SAKI treatment.

H-151 attenuates lipopolysaccharide-induced acute kidney injury by inhibiting the STING-TBK1 pathway

Sepsis is a severe systemic infectious disease that often leads to multi-organ dysfunction. One of the common and serious complications of sepsis is renal injury. In this study, we aimed to investigate the potential mechanistic role of a novel compound called H-151 in septic kidney injury. We also examined its impact on renal function and mouse survival rates. Initially, we confirmed abnormal activation of the STING-TBK1 signaling pathway in the kidneys of septic mice. Subsequently, we treated the mice with H-151 and observed significant improvement in sepsis-induced renal dysfunction. This was evidenced by reductions in blood creatinine and urea nitrogen levels, as well as a marked decrease in inflammatory cytokine levels. Furthermore, H-151 substantially improved the seven-day survival rate of septic mice, indicating its therapeutic potential. Importantly, H-151 also exhibited an inhibitory effect on renal apoptosis levels, further highlighting its mechanism of protecting against septic kidney injury. These study findings not only offer new insights into the treatment of septic renal injury but also provide crucial clues for further investigations into the regulatory mechanisms of the STING-TBK1 signaling pathway and potential drug targets.

EP300-mediated H3 acetylation elevates MTHFD2 expression to reduce mitochondrial dysfunction in lipopolysaccharide-induced tubular epithelial cells

Sepsis represents an organ dysfunction resulting from the host's maladjusted response to infection, and can give rise to acute kidney injury (AKI), which significantly increase the morbidity and mortality of septic patients. This study strived for identifying a novel therapeutic strategy for patients with sepsis-induced AKI (SI-AKI). Rat tubular epithelial NRK-52E cells were subjected to lipopolysaccharide (LPS) exposure for induction of in-vitro SI-AKI. The expressions of E1A binding protein p300 (EP300) and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) in NRK-52E cells were assessed by western blot and qRT-PCR, and their interaction was explored by chromatin immunoprecipitation performed with antibody for H3K27 acetylation (H3K27ac). The effect of them on SI-AKI-associated mitochondrial dysfunction of tubular epithelial cells was investigated using transfection, MTT assay, TUNEL staining, 2',7'-Dichlorodihydrofluorescein diacetate probe assay, Mitosox assay, and JC-1 staining. MTHFD2 and EP300 were upregulated by LPS exposure in NRK-52E cells. LPS increased the acetylation of H3 histone in the MTHFD2 promoter region, and EP300 suppressed the effect of LPS. EP300 ablation inhibited the expression of MTHFD2. MTHFD2 overexpression antagonized LPS-induced viability reduction, apoptosis promotion, reactive oxygen species overproduction, and mitochondrial membrane potential collapse of NRK-52E cells. By contrast, MTHFD2 knockdown and EP300 ablation brought about opposite consequences. Furthermore, MTHFD2 overexpress and EP300 ablation counteracted each other's effect in LPS-exposed NRK-52E cells. EP300-mediated H3 acetylation elevates MTHFD2 expression to reduce mitochondrial dysfunction of tubular epithelial cells in SI-AKI.

Predictive models of sepsis-associated acute kidney injury based on machine learning: a scoping review

BACKGROUND

With the development of artificial intelligence, the application of machine learning to develop predictive models for sepsis-associated acute kidney injury has made potential breakthroughs in early identification, grading, diagnosis, and prognosis determination.

METHODS

Here, we conducted a systematic search of the PubMed, Cochrane Library, Embase (Ovid), Web of Science, and Scopus databases on April 28, 2023, and screened relevant literature. Then, we comprehensively extracted relevant data related to machine learning algorithms, predictors, and predicted objectives. We subsequently performed a critical evaluation of research quality, data aggregation, and analyses.

RESULTS

We screened 25 studies on predictive models for sepsis-associated acute kidney injury from a total of originally identified 2898 studies. The most commonly used machine learning algorithm is traditional logistic regression, followed by eXtreme gradient boosting. We categorized these predictive models into early identification models (60%), prognostic prediction models (32%), and subtype identification models (8%) according to their predictive purpose. The five most commonly used predictors were serum creatinine levels, lactate levels, age, blood urea nitrogen concentration, and diabetes mellitus. In addition, a single data source, insufficient assessment of clinical utility, lack of model bias assessment, and hyperparameter adjustment may be the main reasons for the low quality of the current research.

CONCLUSIONS

However, studies on the nondeath prognostic outcomes, the long-term clinical outcomes, and the subtype identification models are insufficient. Additionally, the poor quality of the research and the insufficient practicality of the model are problems that need to be addressed urgently.

Association Between Inflammatory Biomarkers and Contrast-induced Acute Kidney Injury in ACS Patients Undergoing Percutaneous Coronary Intervention: A Cross-sectional Study

The present study aimed to evaluate the predictive role of inflammatory biomarkers in the development of contrast-induced acute kidney injury (CI-AKI) in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). The inflammatory biomarkers assessed were: platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), neutrophil-to-lymphocyte*platelet ratio (NLPR), systemic inflammatory index (SII), and systemic inflammation response index (SIRI). Overall, 950 patients undergoing PCI were enrolled. The frequency of CI-AKI was 15.2% (n = 144). The levels of NLR, MLR, NLPR, SII, and SIRI were higher in the CI-AKI group than in the Non-CI-AKI group (P < .05). The addition of NLR ≥2.96, dNLR ≥2.08, NLPR ≥.012, SII ≥558.04, and SIRI ≥1.13 to the Mehran score model significantly increased the area under the curve (P < .05). Multivariable logistic regression analyses indicated that inflammatory biomarkers were significantly associated with CI-AKI, including NLR ≥2.96 (OR = 1.588, P = .017), dNLR ≥2.08 (OR = 1.686, P = .007), SII ≥558.04 (OR = 1.521, P = .030), and SIRI ≥1.13 (OR = 1.601, P = .017). Therefore, inflammation is associated with the development of CI-AKI, and preoperative hematological inflammatory markers could predict the risk of CI-AKI in ACS patients undergoing PCI.

The significance of ferroptosis in renal diseases and its therapeutic potential

Kidney diseases are significant global public health concern, with increasing prevalence and substantial economic impact. Developing novel therapeutic approaches are essential for delaying disease progression and improving patient quality of life. Cell death signifying the termination of cellular life, could facilitate appropriate bodily development and internal homeostasis. Recently, regulated cell death (RCD) forms such as ferroptosis, characterized by iron-dependent lipid peroxidation, has garnered attention in diverse renal diseases and other pathological conditions. This review offers a comprehensive examination of ferroptosis, encompassing an analysis of the involvement of iron and lipid metabolism, the System Xc - /glutathione/glutathione peroxidase 4 signaling, and additional associated pathways. Meanwhile, the review delves into the potential of targeting ferroptosis as a therapeutic approach in the management of acute kidney injury (AKI), chronic kidney disease (CKD), diabetic nephropathy, and renal tumors. Furthermore, it emphasizes the significance of ferroptosis in the transition from AKI to CKD and further accentuates the potential for repurposing drug and utilizing traditional medicine in targeting ferroptosis-related pathways for clinical applications. The integrated review provides valuable insights into the role of ferroptosis in kidney diseases and highlights the potential for targeting ferroptosis as a therapeutic strategy.

Nanoparticles constructed from natural polyphenols are used in acute kidney injury

Acute kidney injury (AKI) is a severe clinical syndrome characterized by rapid deterioration of renal function caused by a variety of pathogeneses. Natural polyphenols have been considered to have potential in the treatment of AKI due to their powerful antioxidant and anti-inflammatory activities, but their low bioavailability in vivo limits their efficacy. Polyphenol nanoparticles based on a nano-delivery system show good effects in reducing kidney injury, improving renal function and promoting renal tissue repair, and brings new hope and possibility for the treatment of AKI. This review provides an overview of the common characteristics, treatments, and associated adverse effects of AKI. The classification and bioavailability of polyphenols as well as their therapeutic role in AKI and potential possible effects are outlined. The potential therapeutic effects of polyphenol-based nanoparticles on AKI and the underlying mechanisms are discussed.

Aquaporin 1 is renoprotective in septic acute kidney injury by attenuating inflammation, apoptosis and fibrosis through inhibition of P53 expression

Sepsis associated Acute kidney injury (AKI) is a common clinical syndrome characterized by suddenly decreased in renal function and urinary volume. This study was designed to investigate the role of Aquaporin 1 (AQP1) and P53 in the development of sepsis-induced AKI and their potential regulatory mechanisms. Firstly, transcriptome sequencing analysis of mice kidney showed AQP1 expression was reduced and P53 expression was elevated in Cecal ligation and puncture (CLP)-induced AKI compared with controls. Bioinformatics confirmed that AQP1 expression was remarkably decreased and P53 expression was obviously elevated in renal tissues or peripheral blood of septic AKI patients. Moreover, we found in vivo experiments that AQP1 mRNA levels were dramatically decreased and P53 mRNA significantly increased following the increased expression of inflammation, apoptosis, fibrosis, NGAL and KIM-1 at various periods in septic AKI. Meanwhile, AQP1 and P53 protein levels increased significantly first and then decreased gradually in kidney tissue and serum of rats in different stages of septic AKI. Most importantly, in vivo and vitro experiments demonstrated that silencing of AQP1 greatly exacerbates renal or cellular injury by up-regulating P53 expression promoting inflammatory response, apoptosis and fibrosis. Overexpression of AQP1 prevented the elevation of inflammation, apoptosis and fibrosis by down-regulating P53 expression in Lipopolysaccharide (LPS)-induced AKI or HK-2 cells. Therefore, our results suggested that AQP1 plays a protective role in modulating AKI and can attenuate inflammatory response, apoptosis and fibrosis via downregulating P53 in septic AKI or LPS-induced HK-2cells. The pharmacological targeting of AQP1 mediated P53 expression might be identified as potential targets for the early treatment of septic AKI.

Association between the mean perfusion pressure and the risk of acute kidney injury in critically ill patients with sepsis: a retrospective cohort study

BACKGROUND

Mean perfusion pressure (MPP) has recently emerged as a potential biomarker for personalized management of tissue perfusion in critically ill patients. However, its association with the occurrence of acute kidney injury (AKI) in septic patients and the optimal MPP range remain uncertain. Therefore, this study aims to investigate the relationship between MPP and AKI in critically ill patients with sepsis.

METHODS

We identified 5867 patients with sepsis from the MIMIC-IV database who met the inclusion and exclusion criteria. The exposure variable was the first set of MPP measured within 24 h after ICU admission with invasive hemodynamic monitoring. The primary outcome was the incidence of AKI at 7 days following ICU admission according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Secondary outcomes included in-hospital mortality, lengths of ICU, and hospital stay. Optimal cut-off point for MPP were determined using the Youden index, and multivariable logistic regression was employed to examine the association between MPP and AKI. Subgroup analyses were conducted to enhance result robustness. Kaplan-Meier survival analysis was utilized to evaluate in-hospital mortality rates categorized by MPP.

RESULTS

A total of 5,867 patients with sepsis were included in this study, and the overall incidence of AKI was 82.3%(4828/5867). Patients were categorized into low MPP (< 63 mmHg) and high MPP (≥ 63 mmHg) groups using the optimal ROC curve-derived cut-off point. The incidence of AKI in the low MPP group was higher than that in the high MPP group (87.6% vs. 78.3%, P < 0.001). Multivariable logistic regression analysis adjusted for confounding factors revealed that each 1 mmHg increase in MPP as a continuous variable was associated with a 2% decrease in AKI incidence within 7 days of ICU admission (OR:0.98, 95%CI:0.97-0.99, P < 0.001). When MPP was used as a categorical variable, patients in the high MPP group had a lower risk of AKI than those in the low MPP group (OR:0.71, 95%CI:0.61-0.83, P = 0.001). Subgroup analyses demonstrated a consistent association between MPP and AKI risk across all variables assessed (P for interaction all > 0.05). Kaplan-Meier curve analysis demonstrated a higher survival rate during hospitalization in the high MPP group compared to the low MPP group (Log-rank test, P < 0.0001).

CONCLUSIONS

Lower levels of MPP are associated with an increased incidence of AKI at 7 days in critically ill patients with sepsis.

Ferroptosis and inflammation are modulated by the NFIL3-ACSL4 axis in sepsis associated-acute kidney injury

Sepsis-associated acute kidney injury (SA-AKI) increases the risk of death in patients with sepsis, and its major pathological change is the death of renal tubular cells. However, the mechanism of its occurrence remains unclear. Sepsis can lead to circadian dysregulation, and the rhythm gene NFIL3 has been reported to regulate lipid metabolism. There is compelling evidence that has demonstrated that lipid peroxidation can cause cellular ferroptosis. In this study, we established the in vitro and in vivo models of SA-AKI and confirmed the presence of ferroptosis of the renal tubular epithelial cells in SA-AKI. In addition, analysis of the GEO database showed that NFIL3 was highly expressed in sepsis patients and was highly correlated with the key molecule of ferroptosis, ACSL4. The in vitro and in vivo data suggested that NFIL3 was involved in ferroptosis and inflammation in SA-AKI. Subsequently, loss-of-function experiments revealed that NFIL3 knockdown attenuated ferroptosis and inflammation in renal tubular epithelial cells by downregulating ACSL4 expression, thus protecting SA-AKI. In conclusion, this study is the first to illustrate the involvement of the rhythm gene NFIL3 in SA-AKI, providing new insights and potential therapeutic targets for SA-AKI.

A meta-analysis of risk factors for acute kidney injury in pneumonia: Effectiveness of nursing interventions

INTRODUCTION

The spread of coronavirus disease 2019 (COVID-19) worldwide since November 2019 is of interest to understand its impact on various organs. COVID-19 patients experience a higher incidence of acute kidney injury (AKI) compared with non-COVID-19 patients.

METHODS

A systematic literature search was conducted that covered the period from November 1, 2019 to February 28, 2021.

RESULTS

The analysis incorporated a comprehensive review of 19 studies of 21 362 patients. The older age (mean difference [MDs] = 5.11), cardiovascular disease (CVD) (odds ratio [OR] = 1.94), male sex (OR = 1.55), chronic kidney disease (CKD) (OR = 3.82), hypertension (OR = 2.15), diabetes (OR = 1.71), cancer (OR = 1.16), and chronic obstructive pulmonary disease (COPD) (OR = 1.40), mechanical ventilation (OR = 8.66), and vasopressor (OR = 6.30), were significantly associated with risk factor for AKI (P < 0.05).

CONCLUSION

The analysis revealed independent risk factors for AKI.

MicroRNA‑17‑5p alleviates sepsis‑related acute kidney injury in mice by modulating inflammation and apoptosis

Septic acute kidney injury (AKI) is considered as a severe and frequent complication that occurs during sepsis. Mounting evidence has confirmed the pivotal pathogenetic roles of microRNA (miRNA or miR) in sepsis‑induced AKI; however, the role of miRNAs and their underlying mechanisms in sepsis‑induced AKI have not been entirely understood. The present study aimed to elucidate the functions of special miRNAs during sepsis‑induced AKI and its underlying mechanism. First, a number of differently expressed miRNAs was identified based on the microarray dataset GSE172044. Subsequently, lipopolysaccharide (LPS) was used to induce AKI in mice, and the role of miR‑17‑5p on AKI was clarified. Finally, the related molecular mechanisms were further examined by western blotting and immunohistochemical analysis. MiR‑17‑5p was found to be continuously decreased and reached the bottom at h 24 after AKI in mice. Functionally, injection of agomiR‑17‑5p could observably improve renal injury and survival rate, as well as inhibit inflammatory cytokine production and renal cell apoptosis in mice after AKI. On the contrary, injection of antagomiR‑17‑5p aggravated LPS‑induced renal injury, inflammation and apoptosis in mice after AKI. Moreover, transforming growth factor β receptor 2 (TGFβR2) was identified as a direct target of miR‑17‑5p, and its downstream phosphorylated Smad3 was also suppressed by miR‑17‑5p upregulation. Taken together, these results demonstrated that miR‑17‑5p overexpression may exhibit a beneficial effect by attenuating LPS‑induced inflammation and apoptosis via regulating the TGFβR2/TGF‑β/Smad3 signaling pathway, indicating that miR‑17‑5p could act as a potential target for sepsis treatment.

Emodin inhibits M1 macrophage activation that related to acute and chronic kidney injury through EGFR/MAPK pathway

BACKGROUND

Macrophages are the main inflammatory cells involved in kidney injury and play a significant role in the development of acute kidney injury (AKI) and progression of chronic kidney disease (CKD). Emodin is believed to stabilize macrophage homeostasis under pathological conditions. The objective of this study aimed to explore the underlying mechanisms and effects of Emodin on M1 macrophages.

METHODS

Network pharmacology methods were used to predict target proteins associated with renal injury and identify the pathways affected by emodin. RAW264.7 macrophages were induced into M1 polarization using LPS and then treated with emodin at 20, 40, and 80 µM. The effects of emodin on cell viability, cytokines (IL-1β, IL-6, TNF-α), M1 macrophage markers (F4/80 + CD86+), and the EGFR/MAPK pathway were evaluated. Additionally, we transfected RAW264.7 cells with an EGFR shRNA interference lentivirus to assess its effects on RAW264.7 cells function and MAPK pathway. After RAW264.7 cells were passaged to expanded culture and transfected with EGFR-interfering plasmid, macrophages were induced to polarize towards M1 with LPS and then treated with 80 µM emodin. CKD modeling was performed to test how emodin is regulated during CKD.

RESULTS

There are 15 common targets between emodin and kidney injury, of which the EGFR/MAPK pathway is the pathway through which emodin affects macrophage function. Emodin significantly reduced the levels of IL-6, IL-1β and TNF-α (p < 0.05) and the ratio of M1 macrophage surface markers F4/80 + CD86+ (p < 0.01) in the supernatant of RAW264.7 cells in a dose-dependent manner. Furthermore, the inhibitory effect of emodin on RAW264.7 cells was achieved by interfering with the EGFR/MAPK pathway. Moreover, emodin also affected the mRNA and protein expression of EGFR and Ras, leading to a decrease in the rate of M1 macrophages, thus inhibiting the pro-inflammatory effect of M1 macrophages. The addition of emodin reduced the rate of M1 macrophages in CKD and inhibited the further polarization of M1 macrophages, thus maintaining the pro-inflammatory and anti-inflammatory homeostasis in CKD, and these effects were achieved by emodin through the control of the EGRF/ERK pathway.

CONCLUSION

Emodin attenuates M1 macrophage polarization and pro-inflammatory responses via the EGFR/MAPK signalling pathway. And the addition of emodin maintains pro- and anti-inflammatory homeostasis, which is important for maintaining organ function and tissue repair.

ALBI Grade Is Associated with Clinical Outcomes of Critically Ill Patients with AKI: A Cohort Study with Cox Regression and Propensity Score Matching

Background

The albumin-bilirubin (ALBI) grade has surfaced as a viable substitute for assessing liver functional reserve in individuals afflicted with hepatocellular carcinoma (HCC). ALBI grade also demonstrates the capacity to stratify distinct patient subcohorts bearing disparate prognostic implications in not only HCC but also other inflammatory diseases like acute pancreatitis. However, the association between ALBI grade and clinical outcomes of acute kidney injury (AKI) remains mysterious.

Methods

The dataset was sourced from the Multiparameter Intelligent Monitoring in Intensive Care Database IV (MIMIC-IV) version 2.0. ALBI grade was calculated in a nomogram utilizing albumin and bilirubin. In order to ascertain the connection between ALBI grades and clinical outcomes of patients with AKI, Cox proportional hazards regression analysis was employed with in-hospital, 30- and 90-day mortality as end points, respectively. The Kaplan-Meier (K-M) curve was employed to gauge the cumulative incidence of mortality based on various ALBI grades. To explore potential nonlinear relationships, the Restricted Cubic Spline (RCS) approach was adopted. Furthermore, a subgroup analysis was conducted to validate the durability of the correlation between ALBI grade and in-hospital mortality. Furthermore, equilibrium of confounding variables was also achieved through the application of propensity score matching (PSM).

Results

The study encompassed a total of 12,518 patients (ALBI grade 1 : 2878, grade 2 : 6708, and grade 3 : 2932). Patients with heightened ALBI grades displayed a significant correlation with increased mortality in both univariate and various multivariate Cox regression models. RCS depicted a predominantly linear relationship. The robustness of the correlation was also affirmed across multifarious subpopulations through subgroup analysis. The association still remains after PSM.

Conclusion

Elevated ALBI grade was associated with worse clinical outcomes of critically ill patients with AKI.

Predictive enrichment for the need of renal replacement in sepsis-associated acute kidney injury: combination of furosemide stress test and urinary biomarkers TIMP-2 and IGFBP-7

BACKGROUND

In sepsis, initial resuscitation with fluids is followed by efforts to achieve a negative fluid balance. However, patients with sepsis-associated acute kidney injury (SA-AKI) often need diuretic or renal replacement therapy (RRT). The dilemma is to predict whether early RRT might be advantageous or diuretics will suffice. Both the Furosemide Stress Test (FST) and measurements of the urinary biomarkers TIMP-2*IGFBP-7, if applied solely, do not provide sufficient guidance. We tested the hypothesis that a combination of two tests, i.e., an upstream FST combined with downstream measurements of urinary TIMP-2*IGFBP-7 concentrations improves the accuracy in predicting RRT necessity.

METHODS

In this prospective, multicenter study 100 patients with sepsis (diagnosed < 48h), AKI stage ≥ 2, and an indication for negative fluid balance were included between 02/2020 and 12/2022. All patients received a standardized FST and urinary biomarkers TIMP-2*IGFBP-7 were serially measured immediately before and up to 12 h after the FST. The primary outcome was the RRT requirement within 7 days after inclusion.

RESULTS

32% (n = 32/99) of SA-AKI patients eventually required RRT within 7 days. With the FST, urine TIMP-2*IGFBP-7 decreased within 2 h from 3.26 ng2/mL2/1000 (IQR: 1.38-5.53) to 2.36 ng2/mL2/1000 (IQR: 1.61-4.87) in RRT and 1.68 ng2/mL2/1000 (IQR: 0.56-2.94) to 0.27 ng2/mL2/1000 (IQR: 0.12-0.89) and non-RRT patients, respectively. While TIMP-2*IGFBP-7 concentrations remained low for up to 12 h in non-RRT patients, we noted a rebound in RRT patients after 6 h. TIMP-2*IGFBP-7 before FST (accuracy 0.66; 95%-CI 0.55-0.78) and the FST itself (accuracy 0.74; 95%-CI: 0.64-0.82) yielded moderate test accuracies in predicting RRT requirement. In contrast, a two-step approach, utilizing FST as an upstream screening tool followed by TIMP-2*IGFBP-7 quantification after 2 h improved predictive accuracy (0.83; 95%-CI 0.74-0.90, p = 0.03) compared to the FST alone, resulting in a positive predictive value of 0.86 (95%-CI 0.64-0.97), and a specificity of 0.96 (95%-CI 0.88-0.99).

CONCLUSIONS

The combined application of an upstream FST followed by urinary TIMP-2*IGFBP-7 measurements supports highly specific identification of SA-AKI patients requiring RRT. Upcoming interventional trials should elucidate if this high-risk SA-AKI subgroup, identified by our predictive enrichment approach, benefits from an early RRT initiation.

Inferior vena cava-aortic ratio measurement as a promising modality in assessing intravascular volume in children with sepsis

BACKGROUND

Hemodynamic monitoring is crucial for the comprehensive management of children with sepsis, particularly those involving the kidneys. Sepsis-associated acute kidney injury (S-AKI) is closely linked to poor outcomes. Recently, ultrasonography modalities have been widely accepted as a non-invasive, rapid, and reliable tool for assessing volume status. We conducted research to determine intravascular volume based on ultrasound examination in S-AKI patients.

METHODS

A prospective cohort study was conducted between December 2023 and March 2024 in the Pediatric Intensive Care Unit (PICU) at Hasan Sadikin General Hospital. We divided the patients into two groups: those with sepsis without AKI and those with S-AKI. The intravascular volume was measured by the IVC/Ao (inferior vena cava/abdominal aorta) ratio using two-dimensional ultrasonography and USCOM before and 24 h after fluid treatment. The results were analyzed using SPSS 25, with a significance level of p < 0.05.

RESULTS

A total of 36 pediatric patients (aged 1 month-18 years) with sepsis were included. The IVC/Ao ratio before and after the fluid intervention demonstrated significant differences between the two groups (p < 0.001). USCOM Cardiac Index (CI) before and after the intervention also showed significant differences between the two groups (p < 0.001). Patients with S-AKI exhibited a poor hemodynamic response in the IVC/Ao ratio two-dimensional ultrasonography and USCOM examination.

CONCLUSIONS

IVC/Ao ratio measurement is as accurate as USCOM and can be used as a simple and cost-effective alternative for hemodynamic monitoring.

Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury

Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein-protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.

Association between systemic inflammation biomarkers and mortality in patients with sepsis-associated acute kidney injury receiving intensive care and continuous kidney replacement therapy: results from the RENERGY (REsearches for NEphRology and epidemioloGY) study

BACKGROUND

Identifying risk factors and improving prognostication for mortality among patients with sepsis-associated acute kidney injury (AKI) undergoing continuous kidney replacement therapy (CKRT) is important in improving the adverse prognosis of this patient population. This study aimed to compare the prognostic value of existing systemic inflammation biomarkers and determine the optimal systemic inflammation biomarker in patients with sepsis-associated AKI receiving CKRT.

METHODS

This multi-center, retrospective, observational cohort study included 1,500 patients with sepsis-associated AKI treated with intensive care and CKRT. The main predictor was a panel of 13 different systemic inflammation biomarkers. The primary outcome was 28-day mortality after CKRT initiation. Secondary outcomes included 90-day mortality after CKRT initiation, CKRT duration, kidney replacement therapy dependence at discharge, and lengths of intensive care unit (ICU) and hospital stays.

RESULTS

When added to the widely accepted Acute Physiology and Chronic Health Evaluation II score, platelet-to-albumin ratio (PAR) and neutrophil-platelet score (NPS) had the highest improvements in prognostication of 28-day mortality, where the corresponding increases in C-statistic were 0.01 (95% confidence interval [CI], 0.00-0.02) and 0.02 (95% CI, 0.01-0.03). Similar findings were observed for 90-day mortality. The 28- and 90-day mortality rates were significantly lower for the higher PAR and NPS quartiles. These associations remained significant even after adjustment for potential confounding variables in multivariable Cox proportional hazards models.

CONCLUSION

Of the available systemic inflammation biomarkers, the addition of PAR or NPS to conventional ICU prediction models improved the prognostication of patients with sepsis-associated AKI receiving intensive care and CKRT.

Artificial intelligence and machine learning's role in sepsis-associated acute kidney injury

Sepsis-associated acute kidney injury (SA-AKI) is a serious complication in critically ill patients, resulting in higher mortality, morbidity, and cost. The intricate pathophysiology of SA-AKI requires vigilant clinical monitoring and appropriate, prompt intervention. While traditional statistical analyses have identified severe risk factors for SA-AKI, the results have been inconsistent across studies. This has led to growing interest in leveraging artificial intelligence (AI) and machine learning (ML) to predict SA-AKI better. ML can uncover complex patterns beyond human discernment by analyzing vast datasets. Supervised learning models like XGBoost and RNN-LSTM have proven remarkably accurate at predicting SA-AKI onset and subsequent mortality, often surpassing traditional risk scores. Meanwhile, unsupervised learning reveals clinically relevant sub-phenotypes among diverse SA-AKI patients, enabling more tailored care. In addition, it potentially optimizes sepsis treatment to prevent SA-AKI through continual refinement based on patient outcomes. However, utilizing AI/ML presents ethical and practical challenges regarding data privacy, algorithmic biases, and regulatory compliance. AI/ML allows early risk detection, personalized management, optimal treatment strategies, and collaborative learning for SA-AKI management. Future directions include real-time patient monitoring, simulated data generation, and predictive algorithms for timely interventions. However, a smooth transition to clinical practice demands continuous model enhancements and rigorous regulatory oversight. In this article, we outlined the conventional methods used to address SA-AKI and explore how AI and ML can be applied to diagnose and manage SA-AKI, highlighting their potential to revolutionize SA-AKI care.

Effect of proton pump inhibitors versus histamine-2 receptor antagonists on acute kidney injury in septic patients at high risk for developing stress ulcers

BACKGROUND

To compare the effects of proton pump inhibitor (PPI) and histamine-2 receptor antagonist (H2RA) use on the occurrence of acute kidney injury (AKI) in septic patients at high risk for developing stress ulcers.

METHODS

Using the Medical Information Mart for Intensive Care IV version 2.2 database, septic patients with high-risk factors for stress ulcers (i.e., shock, coagulopathy, invasive mechanical ventilation, or chronic liver diseases) were included. Exposures included PPIs and H2RAs within 24 h of intensive care unit (ICU) admission or prior to ICU admission. The primary end point was severe sepsis-associated AKI as defined by the Kidney Disease Improving Global Outcomes criteria stage 3 (KDIGO-3). Propensity score matching (PSM) was performed to balance baseline characteristics. Multivariable Cox proportional hazards regression was used to estimate the effect size.

RESULTS

4731 PPI users and 4903 H2RA users were included. After PSM, there were 1785 pairs exposed to PPIs and H2RAs. In the PSM cohort, the cumulative incident KDIGO-3 rate was higher in the PPI group than in the H2RA group (log-rank test, p = 0.009). Regression analyses showed that PPI exposure [adjusted hazard ratio 1.32, 95% confidence interval (CI) 1.11-1.58, p = 0.002] was associated with incident KDIGO-3 compared with H2RA use. This association remained consistent in sensitivity analyses. Additionally, the PPI group had a higher need for kidney replacement therapy compared with the H2RA group (3.6% vs. 2.1%, P = 0.012).

CONCLUSIONS

Among septic patients at high risk for developing stress ulcers, PPI exposure was associated with incident KDIGO-3 AKI compared with H2RA use.

A novel marine-derived anti-acute kidney injury agent targeting peroxiredoxin 1 and its nanodelivery strategy based on ADME optimization

Insufficient therapeutic strategies for acute kidney injury (AKI) necessitate precision therapy targeting its pathogenesis. This study reveals the new mechanism of the marine-derived anti-AKI agent, piericidin glycoside S14, targeting peroxiredoxin 1 (PRDX1). By binding to Cys83 of PRDX1 and augmenting its peroxidase activity, S14 alleviates kidney injury efficiently in Prdx1-overexpression (Prdx1-OE) mice. Besides, S14 also increases PRDX1 nuclear translocation and directly activates the Nrf2/HO-1/NQO1 pathway to inhibit ROS production. Due to the limited druggability of S14 with low bioavailability (2.6%) and poor renal distribution, a pH-sensitive kidney-targeting dodecanamine-chitosan nanoparticle system is constructed to load S14 for precise treatment of AKI. l-Serine conjugation to chitosan imparts specificity to kidney injury molecule-1 (Kim-1)-overexpressed cells. The developed S14-nanodrug exhibits higher therapeutic efficiency by improving the in vivo behavior of S14 significantly. By encapsulation with micelles, the AUC0‒t , half-life time, and renal distribution of S14 increase 2.5-, 1.8-, and 3.1-fold, respectively. The main factors contributing to the improved druggability of S14 nanodrugs include the lower metabolic elimination rate and UDP-glycosyltransferase (UGT)-mediated biotransformation. In summary, this study identifies a new therapeutic target for the marine-derived anti-AKI agent while enhancing its ADME properties and druggability through nanotechnology, thereby driving advancements in marine drug development for AKI.

Histone H3K18 and Ezrin Lactylation Promote Renal Dysfunction in Sepsis-Associated Acute Kidney Injury

Histone lactylation is a metabolic stress-related histone modification. However, the role of histone lactylation in the development of sepsis-associated acute kidney injury (SA-AKI) remains unclear. Here, histone H3K18 lactylation (H3K18la) is elevated in SA-AKI, which is reported in this study. Furthermore, this lactate-dependent histone modification is enriched at the promoter of Ras homolog gene family member A (RhoA) and positively correlated with the transcription. Correction of abnormal lactate levels resulted in a reversal of abnormal histone lactylation at the promoter of RhoA. Examination of related mechanism revealed that histone lactylation promoted the RhoA/Rho-associated protein kinase (ROCK) /Ezrin signaling, the activation of nuclear factor-κB (NF-κB), inflammation, cell apoptosis, and aggravated renal dysfunction. In addition, Ezrin can undergo lactylation modification. Multiple lactylation sites are identified in Ezrin and confirmed that lactylation mainly occurred at the K263 site. The role of histone lactylation is revealed in SA-AKI and reportes a novel post-translational modification in Ezrin. Its potential role in regulating inflammatory metabolic adaptation of renal proximal tubule epithelial cells is also elucidated. The results provide novel insights into the epigenetic regulation of the onset of SA-AKI.

Zn2+ improves sepsis-induced acute kidney injury by upregulating SIRT7-mediated Parkin acetylation

Zn2+ levels are reported to be correlated with kidney function. We explored the significance of Zn2+ in sepsis-induced acute kidney injury (SI-AKI) through the regulation of sirtuin 7 (SIRT7) activity. The sepsis rat model was established by cecal ligation and perforation (CLP) and intraperitoneally injected with ZnSO4 or SIRT7 inhibitor 97491 (SIRT7i), with renal tubular injury assessed by hematoxylin and eosin staining. In vitro, human renal tubular epithelial cells (HK-2) were induced with lipopolysaccharide to obtain a renal injury cell model, followed by ZnSO4 or SIRT7i and autophagy inhibitor (3-methyladenine) treatment. Interleukin (IL)-1β, IL-18, reactive oxygen species (ROS), Parkin acetylation level, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were determined. The renal tubule injury, inflammation condition, and pyroptosis-related and autophagy-related protein levels were assessed. The pyroptosis in kidney tissues and autophagosome formation were observed by transmission electron microscopy. Zn2+ alleviated renal injury in CLP rats and inhibited pyroptosis and its related protein levels by inhibiting SIRT7 activity in septic rat renal tissues. In vitro, Zn2+ increased HK-2 cell viability and reduced KIM-1, NGAL, IL-1β, IL-18, NLRP3 inflammasome, cleaved caspase-1, gasdermin D-N levels, and pyroptotic cell number. Zn2+ increased autophagosome number and LC3BII/LC3BI ratio and decreased TOM20, TIM23, P62, and mitochondrial ROS levels. Zn2+ increased Parkin acetylation by repressing SIRT7 activity. Inhibiting mitophagy partially averted Zn2+-inhibited NLRP3 inflammasome activation and apoptosis in HK-2 cells. Zn2+ upregulated Parkin acetylation by repressing SIRT7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving SI-AKI.NEW & NOTEWORTHY Zn2+ upregulated Parkin acetylation by repressing sirtuin 7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving sepsis-induced acute kidney injury.

Ribonuclease inhibitor 1 emerges as a potential biomarker and modulates inflammation and iron homeostasis in sepsis

Sepsis, marked by organ dysfunction, necessitates reliable biomarkers. Ribonuclease inhibitor 1 (RNH1), a ribonuclease (RNase) inhibitor, emerged as a potential biomarker for acute kidney injury and mortality in thoracoabdominal aortic aneurysm patients. Our study investigates RNH1 dynamics in sepsis, its links to mortality and organ dysfunction, and the interplay with RNase 1 and RNase 5. Furthermore, we explore RNH1 as a therapeutic target in sepsis-related processes like inflammation, non-canonical inflammasome activation, and iron homeostasis. We showed that RNH1 levels are significantly higher in deceased patients compared to sepsis survivors and correlate with creatine kinase, aspartate and alanine transaminase, bilirubin, serum creatinine and RNase 5, but not RNase 1. RNH1 mitigated LPS-induced TNFα and RNase 5 secretion, and relative mRNA expression of ferroptosis-associated genes HMOX1, FTH1 and HAMP in PBMCs. Monocytes were identified as the predominant type of LPS-positive PBMCs. Exogenous RNH1 attenuated LPS-induced CASP5 expression, while increasing IL-1β secretion in PBMCs and THP-1 macrophages. As RNH1 has contradictory effects on inflammation and non-canonical inflammasome activation, its use as a therapeutic agent is limited. However, RNH1 levels may play a central role in iron homeostasis during sepsis, supporting our clinical observations. Hence, RNH1 shows promise as biomarkers for renal and hepatic dysfunction and hepatocyte injury, and may be useful in predicting the outcome of septic patients.

Role of OPG/RANKL/RANK/TLR4 signaling pathway in sepsis-associated acute kidney injury

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) has high mortality rates. The osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/receptor activator of nuclear factor-κB (RANK)/Toll-like receptor 4 (TLR4) pathway and its potential role in SA-AKI pathogenesis remain to be fully understood. Herein, we addressed this issue using mouse models.

METHODS

An SA-AKI mouse model was established using the cecal ligation and puncture method (CLP). Mice were grouped into sham, CLP model, CLP + recombinant RANKL, and CLP + anti-RANKL groups. Serum creatinine (Scr) and blood urea nitrogen (BUN) levels were measured to assess kidney function. ELISA was used to detect serum IL-1β, TNF-α, and IL-6 levels. Real-time quantitative PCR and Western blot were used to detect the mRNA and protein expression levels of OPG, RANKL, RANK, and TLR4 in kidney tissues. HE staining was performed to evaluate the pathological changes.

RESULTS

The CLP model group showed higher levels of Scr and BUN, indicating impaired kidney function in SA-AKI, compared to the sham group. Treatment with recombinant RANKL in the CLP + recombinant RANKL group reduced Scr and BUN levels, while anti-RANKL treatment in the CLP + anti-RANKL group elevated their levels. Moreover, the CLP model group had significantly increased IL-1β, TNF-α, and IL-6 than the sham group, indicating elevated inflammation in SA-AKI. The CLP + recombinant RANKL group demonstrated decreased cytokine levels, whereas the CLP + anti-RANKL group showed an increase. Additionally, the histopathological evaluation revealed distinct kidney tissue damage in the CLP model group. Recombinant RANKL treatment reduced this damage, while anti-RANKL treatment exacerbated it. Mechanically, the mRNA and protein expression of RANKL were significantly decreased, while those of OPG, RANK, and TLR4 were significantly increased in the CLP model group and the CLP + anti-RANKL group. Interestingly, treatment with recombinant RANKL reversed these changes, as evidenced by significantly increased RANKL but decreased OPG, RANK, and TLR4.

CONCLUSION

The OPG/RANKL/RANK/TLR4 pathway is involved in SA-AKI pathogenesis. Recombinant RANKL treatment attenuates the inflammatory response and kidney tissue damage in SA-AKI, possibly via regulating this pathway. This pathway shows promise as a therapeutic target for SA-AKI.

Neutrophil-Mediated Nanozyme Delivery System for Acute Kidney Injury Therapy

Reactive oxygen species (ROS) scavenging of nanozymes toward acute kidney injury (AKI) is a current promising strategy, however, the glomerular filtration barrier (GFB) limits their application for treating kidney related diseases. Here, a neutrophil-mediated delivery system able to hijack neutrophil to transport nanozyme-loaded cRGD-liposomes to inflamed kidney for AKI treatment by cRGD targeting integrin αvβ1 is reported. The neutrophil-mediated nanozyme delivery system demonstrated great antioxidant and anti-apoptosis ability in HK-2 and NRK-52E cell lines. Moreover, in ischemia-reperfusion (I/R) induced AKI mice, a single dose of LM@cRGD-LPs 12 h post-ischemia significantly reduces renal function indicators, alleviates renal pathological changes, and inhibits apoptosis of renal tubular cells and the expression of renal tubular injured marker, thus remarkably reducing the damage of AKI. Mechanistically, the treatment of LM@cRGD-LPs markedly inhibits the process of Nrf2 to the nucleus and reduces the expression of the downstream HO-1, achieves a 99.51% increase in renal tissue Nrf2 levels, and an 86.31% decrease in HO-1 levels after LM@cRGD-LPs treatment. In short, the strategy of neutrophil-mediated nanozyme delivery system hold great promise as a potential therapy for AKI or other inflammatory diseases.

Relationship between low molecular weight heparin calcium therapy and prognosis in severe acute kidney injury in sepsis: Mendelian randomized analysis and retrospective study

Background

Sepsis-associated acute kidney injury (SA-AKI) poses an independent risk for mortality due to the absence of highly sensitive biomarkers and a specific treatment plan.

Objective

Investigate the association between low molecular weight heparin (LMWH) calcium therapy and prognosis in critically ill SA-AKI patients, and assess the causal relationship through Mendelian randomization (MR) analysis.

Methods

A single-center, retrospective, cross-sectional study included 90 SA-AKI patients and 30 septic patients without acute kidney injury (AKI) from the intensive care unit (ICU) of the First Hospital of Lanzhou University. SA-AKI patients were categorized into control or LMWH groups based on LMWH calcium usage. Primary outcome was renal function recovery, with secondary outcomes including 28-day mortality, ICU stay length, number of renal replacement therapy (RRT) recipients, and 90-day survival. MR and related sensitivity analyses explored causal effects.

Results

The combination of heparin-binding protein (HBP), heparanase (HPA), and neutrophil gelatinase-associated lipocalin (NGAL) demonstrated high diagnostic value for SA-AKI. MR analysis suggested a potential causal link between gene-predicted HBP and AKI (OR: 1.369, 95%CI: 1.040-1.801, p = 0.024). In the retrospective study, LMWH-treated patients exhibited improved renal function, reduced levels of HPA, HBP, Syndecan-1, and inflammation, along with enhanced immune function compared to controls. However, LMWH did not impact 28-day mortality, 90-day survival, or ICU stay length.

Conclusion

LMWH could enhance renal function in SA-AKI patients. MR analysis supports this causal link, underscoring the need for further validation in randomized controlled trials.

Resveratrol Inhibits circ_0074371-related Pathway to Alleviate Sepsis-induced Acute Kidney Injury

Resveratrol has a protective effect on sepsis-induced acute kidney injury (AKI). Circ_0074371 has been confirmed to inhibit sepsis-induced AKI process, but whether resveratrol inhibits sepsis-induced AKI by regulating circ_0074371-related pathway remains unclear. In this study, lipopolysaccharide (LPS)-induced renal tubular epithelial cells (HK2) were used to mimic AKI cell models. Quantitative real-time PCR was used to detect relative expression of circ_0074371, microRNA (miR)-145-5p and inositol polyphosphate multikinase (IPMK). Cell proliferation and apoptosis were detected by cell counting kit 8 assay, EdU assay and flow cytometry. The levels of inflammation factors were measured by ELISA assay, and MDA level and SOD activity were examined to assess oxidative stress. Protein expression of IPMK was evaluated by western bolt analysis. The relationship between miR-145-5p and circ_0074371 or IPMK was confirmed by dual-luciferase reporter assay. It was showed that circ_0074371 was upregulated in AKI patients and LPS-induced HK2 cells, and silencing of circ_0074371 promoted proliferation and inhibited apoptosis, inflammation and oxidative stress in LPS-induced HK2 cells. In terms of mechanism, circ_0074371 sponged miR-145-5p to positively regulate IPMK. IPMK overexpression could reverse the relieving effect of circ_0074371 knockdown on LPS-induced HK2 cell injury. Moreover, resveratrol suppressed LPS-induced apoptosis, inflammation and oxidative stress in HK2 cells, and circ_0074371 overexpression also reversed the protective effect of resveratrol against LPS-induced cell injury. Our data suggested that resveratrol alleviated LPS-induced HK2 cell injury by inactivating the circ_0074371/miR-145-5p/IPMK axis.

Inhibitory Effect of Puerarin on Lipopolysaccharide-triggered Inflammatory Responses of Bovine Kidney Cells

Puerarin (Pue), a flavonoid compound, possesses cytoprotective effects and LPS has been reported to induce renal inflammatory injury in bovine. However, whether Pue inhibits lipopolysaccharide (LPS)-induced inflammatory damage of bovine kidney cells remains unknown. Based on an in vitro model with Madin-Darby bovine kidney (MDBK) cell line, it has found that Pue attenuated LPS-induced damage of MDBK cells, as evidenced by cell viability and lactic dehydrogenase (LDH) release rescued by Pue (P < 0.05). Additionally, the real-time quantitative PCR (qPCR) and enzyme linked immunosorbent assay (ELISA) showed that LPS elevated the levels of pro-inflammatory factors interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-α, which was reversed by pretreatment of Pue (P < 0.05). Besides, Pue reduced the expression of Toll like receptor 4 (TLR4) and phosphorylated nuclear factor kappa B (p-NF-κB) of LPS-exposed MDBK cells (P < 0.05). Collectively, these results showed that Pue suppresses LPS-evoked inflammatory damage of bovine kidney cells, suggesting Pue a potential compound for intervention of bovine inflammation.

Analysis of risk factors for acute kidney injury in children with severe wasp stings

BACKGROUND

Acute kidney injury (AKI) is common in children with sepsis, chronic kidney disease, poisoning or other conditions. Wasp stings are recognized as an important etiology. Several retrospective studies have investigated AKI after wasp stings in adults, but research on children remains limited.

METHODS

The study included 48 children with multiple organ dysfunction syndrome after wasp stings. Demographic data, clinical manifestations, laboratory findings, management and clinical outcomes were collected, and analyzed to identify early indicators or risk factors for AKI.

RESULTS

20 children (41.7%) developed AKI, and 28 (58.3%) did not. Serum creatine levels elevated mostly within 24 h from stings in children with AKI (16/20, 80%). Compared with non-AKI group, AKI group exhibited more cases with cola-colored urine, jaundice, and had higher sting numbers/body surface area (BSA) and higher revised sequential organ failure assessment scores (rSOFA) as well as higher levels of C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), lactate dehydrogenase (LDH), troponin (cTnI), creatine kinase (CK), and longer prothrombin time (PT). Both univariable and multivariable logistic regression analysis identified cola-colored urine as a potential early risk factor for AKI.

CONCLUSIONS

The AKI group exhibited higher sting numbers/BSA, higher levels of CRP, ALT, AST, TBIL, LDH, cTnI, and CK, as well as longer PT (p < 0.05). Our findings also suggest that cola-colored urine may serve as an early indicator or potential risk factor for AKI after wasp stings in children, which is very easy to identify for first aiders or pediatricians.

Mean arterial pressure to norepinephrine equivalent dose ratio for predicting renal replacement therapy requirement: a retrospective analysis from the MIMIC-IV

BACKGROUND

This study aimed to assess the predictive value of the ratio of mean arterial pressure (MAP) to the corresponding peak rate of norepinephrine equivalent dose (NEQ) within the first day in patients with shock for the subsequent renal replacement therapy (RRT) requirement.

METHODS

Patients were identified using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The relationship was investigated using a restricted cubic spline curve, and propensity score matching(PSM) was used to eliminate differences between groups. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using logistic regression. Variable significance was assessed using extreme gradient boosting (XGBoost), and receiver operating characteristic (ROC) curves were generated.

RESULTS

Of the 5775 patients, 301 (5.2%) received RRT. The MAP/NEQ index showed a declining L-shaped relationship for RRT. After PSM, the adjusted OR per 100 mmHg/mcg/kg/min for RRT was 0.93(95% CI 0.88-0.98). The most influential factors for RRT were fluid balance, baseline creatinine, and the MAP/NEQ index. The threshold for the MAP/NEQ index predicting RRT was 161.7 mmHg/mcg/kg/min (specificity: 65.8%, sensitivity: 74.8%) with an area under the ROC curve of 75.9% (95% CI 73.1-78.8).

CONCLUSIONS

The MAP/NEQ index served as an alternative predictor of RRT necessity based on the NEQ for adult patients who received at least one vasopressor over 6 h within the first 24 h of intensive care unit(ICU) admission. Dynamic modulation of the MAP/NEQ index by the synergistic use of various low-dose vasopressors targeting urine output may be beneficial for exploring individualized optimization of MAP.

Effects of metaraminol and norepinephrine on hemodynamics and kidney function in a miniature pig model of septic shock

Objective

To compare the effects of metaraminol and norepinephrine on hemodynamics and kidney injury in the treatment of septic shock, and calculate the conversion dose ratio between the two vasopressors.

Methods

This randomized controlled study was performed on 15 Guizhou miniature pigs. Septic shock was induced by fecal peritonitis in 10 animals, and 5 were used as a sham-operated group (shams). Fluid resuscitation and vasopressors were initiated 30 min after the onset of septic shock. The septic shock pigs were randomly assigned to receive one of the two drugs to restore and maintain mean arterial pressure (MAP) ≥ 65 mmHg for 3 h. Hemodynamics and heart rate were continuously monitored.

Results

There was no significant difference in MAP, heart rate, cardiac output (CO) and central venous pressure (CVP) between the two groups after treatment. No arrhythmias such as atrial fibrillation and ventricular fibrillation presented during continuous monitoring. After septic shock, the animals showed obvious kidney injury. In addition, compared with norepinephrine, the creatinine at 3 h was significantly lower with metaraminol. According to propensity score matching, the ratio of 6: 1 was considered appropriate for the dose equivalence calculation of metaraminol (μg·kg-1·min-1): norepinephrine (μg·kg-1·min-1).

Conclusion

Metaraminol has a similar pressor effect to norepinephrine in septic shock; it does not increase heart rate and aggravate kidney injury after shock compared with norepinephrine. And our research may provide some laboratory evidence for the clinical usage of metaraminol.

Dysfunction of the renin-angiotensin-aldosterone system in human septic shock

Sepsis and septic shock are global healthcare problems associated with mortality rates of up to 40% despite optimal standard-of-care therapy and constitute the primary cause of death in intensive care units worldwide. Circulating biomarkers of septic shock severity may represent a clinically relevant approach to individualize those patients at risk for worse outcomes early in the course of the disease, which may facilitate early and more precise interventions to improve the clinical course. However, currently used septic shock biomarkers, including lactate, may be non-specific and have variable impact on prognosis and/or disease management. Activation of the renin-angiotensin-aldosterone system (RAAS) is likely an early event in septic shock, and studies suggest that an elevated level of renin, the early and committed step in the RAAS cascade, is a better predictor of worse outcomes in septic shock, including mortality, than the current standard-of-care measure of lactate. Despite a robust increase in renin, other elements of the RAAS, including endogenous levels of Ang II, may fail to sufficiently increase to maintain blood pressure, tissue perfusion, and protective immune responses in septic shock patients. We review the current clinical literature regarding the dysfunction of the RAAS in septic shock and potential therapeutic approaches to improve clinical outcomes.

Pyroptosis in sepsis induced organ dysfunction

As an uncontrolled inflammatory response to infection, sepsis and sepsis induced organ dysfunction are great threats to the lives of septic patients. Unfortunately, the pathogenesis of sepsis is complex and multifactorial, which still needs to be elucidated. Pyroptosis is a newly discovered atypical form of inflammatory programmed cell death, which depends on the Caspase-1 dependent classical pathway or the non-classical Caspase-11 (mouse) or Caspase-4/5 (human) dependent pathway. Many studies have shown that pyroptosis is related to sepsis. The Gasdermin proteins are the key molecules in the membrane pores formation in pyroptosis. After cut by inflammatory caspase, the Gasdermin N-terminal fragments with perforation activity are released to cause pyroptosis. Pyroptosis is closely related to the occurrence and development of sepsis induced organ dysfunction. In this review, we summarized the molecular mechanism of pyroptosis, the key role of pyroptosis in sepsis and sepsis induced organ dysfunction, with the aim to bring new diagnostic biomarkers and potential therapeutic targets to improve sepsis clinical treatments.

The renoprotective potential of montelukast: a scoping review

Introduction

Kidney damage can result from various factors, leading to structural and functional changes in the kidney. Acute kidney injury (AKI) refers to a sudden decline in kidney function, while chronic kidney disease involves a gradual deterioration lasting more than 3 months. Mechanisms of renal injury include impaired microcirculation, inflammation, and oxidative stress. Cysteinyl-leukotrienes (CysLTs) are inflammatory substances contributing to tissue damage. Montelukast, a leukotriene receptor antagonist, has shown potential renoprotective effects in experimental models of kidney injury.

Methods

The authors conducted a scoping review using PubMed, Scopus, and Web of Science databases to identify relevant studies investigating the impact of montelukast on renal diseases. Articles published until 2022 were included and evaluated for quality. Data extraction and analysis were performed based on predetermined inclusion criteria.

Results

The scoping review included 30 studies from 8 countries. Montelukast demonstrated therapeutic effects in various experimental models of nephrotoxicity and AKI induced by agents such as cisplatin, lipopolysaccharide, diclofenac, amikacin, Escherichia coli, cyclosporine, methotrexate, cobalt-60 gamma radiation, doxorubicin, and cadmium. Studies involving human subjects with nephrotic syndrome, pyelonephritis, and other renal diseases also reported positive outcomes with montelukast treatment. Montelukast exhibited anti-inflammatory, anti-apoptotic, antioxidant, and neutrophil-inhibiting properties, leading to improved kidney function and histopathological changes.

Conclusions

Montelukast shows promise as a renoprotective medication, particularly in early-stage kidney injury. Its ability to mitigate inflammation, oxidative stress, and neutrophil infiltration contributes to its therapeutic effects. Further research is needed to explore the clinical applications and mechanisms underlying the renoprotective action of montelukast.

Acute Kidney Injury in Sepsis

Sepsis-associated kidney injury is common in critically ill patients and significantly increases morbidity and mortality rates. Several complex pathophysiological factors contribute to its presentation and perpetuation, including macrocirculatory and microcirculatory changes, mitochondrial dysfunction, and metabolic reprogramming. Recovery from acute kidney injury (AKI) relies on the evolution towards adaptive mechanisms such as endothelial repair and tubular cell regeneration, while maladaptive repair increases the risk of progression to chronic kidney disease. Fundamental management strategies include early sepsis recognition and prompt treatment, through the administration of adequate antimicrobial agents, fluid resuscitation, and vasoactive agents as needed. In septic patients, organ-specific support is often required, particularly renal replacement therapy (RRT) in the setting of severe AKI, although ongoing debates persist regarding the ideal timing of initiation and dosing of RRT. A comprehensive approach integrating early recognition, targeted interventions, and close monitoring is essential to mitigate the burden of SA-AKI and improve patient outcomes in critical care settings.

Acteoside and isoacteoside alleviate renal dysfunction and inflammation in lipopolysaccharide-induced acute kidney injuries through inhibition of NF-κB signaling pathway

Acute kidney injury (AKI) is a sudden loss of renal function with a high mortality rate and inflammation is thought to be the underlying cause. The phenylpropanoid components acteoside (ACT) and isoacteoside (ISO), which were isolated from Cistanche deserticola Y.C.Ma, have been reported to have preventive effects against kidney disorders. This study aimed to investigate the anti-inflammatory properties and protective mechanisms of ACT and ISO. In this investigation, kidney function was assessed using a semi-automatic biochemical analyzer, histopathology was examined using Hematoxylin-Eosin staining and immunohistochemistry, and the concentration of inflammatory cytokines was assessed using an enzyme-linked immunosorbent assay (ELISA) test. In addition, using Western blot and q-PCR, the expression of proteins and genes connected to the NF-κB signaling pathway in mice with lipopolysaccharide (LPS)-induced AKI was found. The findings showed that under AKI intervention in LPS group, ACT group and ISO group, the expression of Rela (Rela gene is responsible for the expression of NFκB p65 protein) and Tlr4 mRNA was considerably elevated (P<0.01), which led to a significant improvement in the expression of MyD88, TLR4, Iκ-Bɑ and NF-κB p65 protein (P<0.001). The levels of Alb, Crea and BUN (P<0.001) increased along with the release of downstream inflammatory factors such as IL-1β, IL-6, Cys-C, SOD1 and TNF-α (P<0.001). More importantly, the study showed that ISO had a more favorable impact on LPS-induced AKI mice than ACT. In conclusion, by inhibiting NF-κB signaling pathway, ACT and ISO could relieve renal failure and inflammation in AKI, offering a fresh possibility for the therapeutic management of the condition.

A strategy for oral delivery of FGF21 for mitigating inflammation and multi-organ damage in sepsis

Fibroblast growth factor 21 (FGF21) shows great therapeutic potential in metabolic, neurodegenerative and inflammatory diseases. However, current FGF21 administration predominantly relies on injection rather than oral ingestion due to its limited stability and activity post-gastrointestinal transit, thereby hindering its clinical utility. Milk-derived exosomes (mEx) have emerged as a promising vehicle for oral drug delivery due to their ability to maintain structural integrity in the gastrointestinal milieu. To address the challenge associated with oral delivery of FGF21, we encapsulated FGF21 within mEx (mEx@FGF21) to protect its activity post-oral administration. Additionally, we modified the surface of mEx@FGF21 by introducing transferrin (TF) to enhance intestinal absorption and transport, designated TF-mEx@FGF21. In vitro results demonstrated that the surface modification of TF promoted FGF21 internalization by intestinal epithelial cells. Orally administered TF-mEx@FGF21 showed promising therapeutic effects in septic mice. This study represents a practicable strategy for advancing the clinical application of oral FGF21 delivery.

Diagnostic accuracy of pancreatic stone protein in patients with sepsis: a systematic review and meta-analysis

BACKGROUND

Sepsis is a common syndrome of multiorgan system dysfunction secondary to the dysregulated inflammatory response to infection. The role of pancreatic stone protein (PSP) in diagnosing sepsis has been investigated in previous studies. The meta-analysis aimed to comprehensively investigate the diagnostic value of PSP in identifying sepsis.

METHODS

PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI), were systematically searched. Studies investigating the diagnostic performance of PSP were included. Pooled sensitivity, specificity, positive Likelihood Ratio (+ LR) and negative Likelihood Ratio (-LR), diagnostic odds ratio (DOR), and area under the curve (AUC) of summary receiver operating characteristic (SROC) were calculated.

RESULTS

The sensitivity of PSP was 0.88 (95% CI: 0.77-0.94), and the pooled specificity was 0.78 (95% CI: 0.65-0.87). Pooled + LR, -LR, and DOR were 4.1 (2.3, 7.3), 0.16 (0.07, 0.34), and 26 (7, 98). The AUC value for the SROC of PSP was 0.90 (0.87, 0.92). The pooled sensitivity, specificity, + LR and - LR, and DOR for PSP among neonates were 0.91 (95% CI: 0.84, 0.96), 0.66 (95% CI: 0.58, 0.74), 3.97 (95% CI: 0.53, 29.58), 0.13 (95% CI: 0.02, 1.00), and 31.27 (95% CI: 0.97, 1004.60).

CONCLUSIONS

This study indicates that PSP demonstrated favorable diagnostic accuracy in detecting sepsis. Well-designed studies are warranted to ascertain the value of PSP measurement to guide early empirical antibiotic treatment, particularly in neonates.

Predictive performance of two types of urinary biomarkers for renal non-recovery in sepsis-associated acute kidney injury: a prospective observational study

BACKGROUND AND PURPOSE

Renal non-recovery is known to have negative prognostic implications in patients suffering from acute kidney injury (AKI). Nevertheless, the identification of biomarkers for predicting renal non-recovery in sepsis-associated AKI (SA-AKI) within clinical settings remains unresolved. This study aims to evaluate and compare the predictive ability for renal non-recovery, use of kidney replacement therapy (KRT) in the Intensive Care Unit (ICU), and 30-day mortality after SA-AKI by two urinary biomarkers, namely C-C motif chemokine ligand 14 (CCL14) and [TIMP-2]•[IGFBP7].

METHODS

We prospectively screened adult patients who met the criteria for AKI stage 2-3 and Sepsis-3.0 in two ICUs from January 2019 to May 2022. Patients who developed new-onset SA-AKI after ICU admission were enrolled and urinary biomarkers including [TIMP-2]•[IGFBP7] and CCL14 were detected at the time of SA-AKI diagnosis. The primary endpoint was non-recovery from SA-AKI within 7 days. The secondary endpoints were the use of KRT in the ICU and 30-day mortality after SA-AKI. The individual discriminative ability of [TIMP-2]•[IGFBP7] and CCL14 to predict renal non-recovery were evaluated by the area under receiver operating characteristics curve (AUC).

RESULTS

141 patients with stage 2-3 SA-AKI were finally included, among whom 54 (38.3%) experienced renal non-recovery. Urinary CCL14 exhibited a higher predictive capability for renal non-recovery compared to [TIMP-2]•[IGFBP7], with CCL14 showing an AUC of 0.901, versus an AUC of 0.730 for [TIMP-2]•[IGFBP7] (P = 0.001). Urinary CCL14 and [TIMP-2]•[IGFBP7] demonstrated a moderate predictive value for the need for KRT in ICU, with AUC values of 0.794 and 0.725, respectively; The AUC of [TIMP-2]•[IGFBP7] combined with CCL14 reached up to 0.816. Urinary CCL14 and [TIMP-2]•[IGFBP7] exhibited poor predictive power for 30-day mortality, with respective AUC values of 0.623 and 0.593.

CONCLUSION

Urinary CCL14 had excellent predictive value for renal non-recovery in SA-AKI patients. For predicting the use of KRT in the ICU, the predictive capability of urinary [TIMP-2]•[IGFBP7] or CCL14 was fair. However, a combination of [TIMP-2]•[IGFBP7] and CCL14 showed good predictive ability for the use of KRT.

Molecular mechanism of circHIPK3 in mitochondrial function in septic acute kidney injury

Cell senescence, glycolysis, and mitochondrial deficit jointly regulate the development of septic acute kidney injury (SAKI). This study aimed to explore the role of circular RNA HIPK3 (circHIPK3) in mitochondrial function in SAKI. The SAKI mouse model was established by Candida albicans infection, followed by Western blot assay, measurements of serum lactate, and adenosine triphosphate (ATP), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1) staining and flow cytometry. Human renal tubular epithelial cells were treated with lipopolysaccharide to establish the SAKI cell model, followed by cell counting kit-8 assay, tests of hexokinase activity, lactate production, oxygen consumption rate, extracellular acidification rate, ATP, and JC-1 staining, and Western blot assay. The roles of mitochondrial pyruvate carrier 1 (MPC1) were validated by kidney function tests, hematoxylin and eosin staining, periodic acid-Schiff staining, and SA-β-gal staining. circHIPK3 downregulation reduced glycolysis and mitochondrial dysfunction both in vivo and in vitro through the microRNA (miR)-148b-3p/DNMT1/3a/Klotho axis. Inhibition of miR-148b-3p or Klotho increased glycolysis and mitochondrial dysfunction. Knockdown of MPC1 increased lactate content and decreased ATP levels and MMP both in vivo and in vitro. Collectively, circHIPK3, in concert with the miR-148b-3p/DNMT1/3a/Klotho axis, increased glycolysis, and inhibited the negative regulation of lactate production by MPC1, and aggravated mitochondrial dysfunction and cell senescence in SAKI.

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.

Elevated Activated Partial Thromboplastin Time as a Predictor of 28-Day Mortality in Sepsis-Associated Acute Kidney Injury: A Retrospective Cohort Analysis

Purpose

To address the critical mortality rates among sepsis-associated acute kidney injury (SA-AKI) patients, early prognosis is vital. This study investigates the relationship between coagulation indices and the 28-day mortality rate in patients with SA-AKI.

Patients and Methods

This study was a retrospective cohort analysis including patients with SA-AKI admitted to the First Hospital of Fujian Medical University as a training cohort (n = 119) and patients admitted to the Third People's Hospital of Fujian University of Traditional Chinese Medicine as a validation cohort (n = 51). We examined the relationship between coagulation indices and 28-day mortality in SA-AKI, the cumulative mortality at different activated partial thromboplastin time (APTT) levels, and the nonlinear relationship between APTT and 28-day mortality. Receiver operating characteristic curves were plotted, and the area under the curve was calculated to assess the predictive power of APTT. Finally, subgroup analyses were performed to assess the robustness of the association.

Results

Overall, 119 participants with a mean±standard deviation age of 70.47±15.20 years were included in the training cohort: 54 died, 65 survived. According to univariate and multivariate COX regression analyses, APACHE II score, CRP level, Lac level, and APTT level were independent risk factors for 28-day adverse prognosis. After controlling for some variables, an elevated baseline APTT (≥ 37.7 s) was associated with an elevated risk of 28-day mortality (HR, 1.017; 95% CI, 1.001-1.032), and Kaplan-Meier analyses further confirmed the increased mortality in the group with a higher APTT. The same results were shown when the validation cohort was analyzed (HR, 1.024; 95% CI, 0.958-1.096). Subgroup analyses showed the stability of the association between APTT and poor prognosis in SA-AKI.

Conclusion

In essence, APTT elevation is synonymous with increased 28-day mortality rates, indicating a poor prognosis in SA-AKI scenarios.

Early Identification of Sepsis-Induced Acute Kidney Injury by Using Monocyte Distribution Width, Red-Blood-Cell Distribution, and Neutrophil-to-Lymphocyte Ratio

Sepsis-induced acute kidney injury (AKI) is a common complication in patients with severe illness and leads to increased risks of mortality and chronic kidney disease. We investigated the association between monocyte distribution width (MDW), red-blood-cell volume distribution width (RDW), neutrophil-to-lymphocyte ratio (NLR), sepsis-related organ-failure assessment (SOFA) score, mean arterial pressure (MAP), and other risk factors and sepsis-induced AKI in patients presenting to the emergency department (ED). This retrospective study, spanning 1 January 2020, to 30 November 2020, was conducted at a university-affiliated teaching hospital. Patients meeting the Sepsis-2 consensus criteria upon presentation to our ED were categorized into sepsis-induced AKI and non-AKI groups. Clinical parameters (i.e., initial SOFA score and MAP) and laboratory markers (i.e., MDW, RDW, and NLR) were measured upon ED admission. A logistic regression model was developed, with sepsis-induced AKI as the dependent variable and laboratory parameters as independent variables. Three multivariable logistic regression models were constructed. In Model 1, MDW, initial SOFA score, and MAP exhibited significant associations with sepsis-induced AKI (area under the curve [AUC]: 0.728, 95% confidence interval [CI]: 0.668-0.789). In Model 2, RDW, initial SOFA score, and MAP were significantly correlated with sepsis-induced AKI (AUC: 0.712, 95% CI: 0.651-0.774). In Model 3, NLR, initial SOFA score, and MAP were significantly correlated with sepsis-induced AKI (AUC: 0.719, 95% CI: 0.658-0.780). Our novel models, integrating MDW, RDW, and NLR with initial SOFA score and MAP, can assist with the identification of sepsis-induced AKI among patients with sepsis presenting to the ED.

Urinary PKM2, a marker predicating acute kidney injury in patients with sepsis

PURPOSE

Acute kidney injury (AKI) is a complication commonly occurred in patients with sepsis, and AKI has become the leading cause associated with mortality. PKM2, as a rate-limiting enzyme of glycolysis, was considered to be involved in AKI in vitro and animal models. However, there have been no studies reported on the expression of PKM2 in humans and its association with AKI.

METHODS

A retrospective study including 57 patients (35 males and 22 females) that were admitted into hospital in 2019 was carried out in our research. The basic characteristics and clinical parameters of each patient were collected from patients' medical records. We assessed changes in the expression of serum and urinary PKM2 using ELISA and its association with clinical manifestations in patients with sepsis through correlation analysis. Besides, ROC analysis was applied for evaluating the role of PKM2 in predicting AKI and death rate.

RESULTS

Urinary PKM2 is obviously increased in patients with sepsis-associated AKI (P < 0.05), while no significant change was found in the expression of serum PKM2. Moreover, the expression of urinary PKM2 is positively correlated with serum creatinine (r=0.577, P < 0.01) and blood-urea-nitrogen (r=0.531, P<0.01). In addition, it is negatively correlated with glomerular filtration rate (r=-0.583, P<0.01). Besides, ROC analysis indicated that urinary PKM2 could be a predictor of AKI in patients with sepsis (AUC-ROC, 0.819; SE, 0.086, P = 0.004, 95% CI 0.651-0.986).

CONCLUSIONS

Urinary PKM2 could be a marker predicting acute kidney injury in patients with sepsis.