Acute kidney injury (AKI) is a common clinically critical syndrome in hospitalized patients with high morbidity and mortality. At present, the mechanism of AKI has not been fully elucidated, and no therapeutic drugs exist. As known, glycolytic product lactate is a key metabolite in physiological and pathological processes. The kidney is an important gluconeogenic organ, where lactate is the primary substrate of renal gluconeogenesis in physiological conditions. During AKI, altered glycolysis and gluconeogenesis in kidneys significantly disturb the lactate metabolic balance, which exert impacts on the severity and prognosis of AKI. Additionally, lactate-derived posttranslational modification, namely lactylation, is novel to AKI as it could regulate gene transcription of metabolic enzymes involved in glycolysis or Warburg effect. Protein lactylation widely exists in human tissues and may severely affect non-histone functions. Moreover, the strategies of intervening lactate metabolic pathways are expected to bring a new dawn for the treatment of AKI. This review focused on renal lactate metabolism, especially in proximal renal tubules after AKI, and updated recent advances of lactylation modification, which may help to explore potential therapeutic targets against AKI.
Humans ; Acute Kidney Injury/metabolism* ; Lactic Acid/metabolism* ; Animals ; Glycolysis/physiology* ; Gluconeogenesis/physiology* ; Kidney/metabolism*

Acute kidney injury (AKI) affects more than 20% of hospitalized patients and is a significant contributor to morbidity and mortality, primarily due to ischemia-reperfusion injury (IRI), which is one of the leading causes of AKI. IRI not only exacerbates the immediate impact of AKI but also facilitates its progression to chronic kidney disease (CKD) and, in cases of preexisting CKD, to end-stage renal disease (ESRD). One of the critical pathological processes associated with IRI-AKI is cellular senescence, characterized by an irreversible arrest in the cell cycle, morphological and chromatin organization changes, altered transcriptional and metabolic profiles, and the development of a hypersecretory phenotype known as the senescence-associated secretory phenotype (SASP). The SASP amplifies senescence signals in surrounding normal cells through senescence-related pathways, contributing to tissue damage, fibrosis, and chronic inflammation. This review provides an overview of the defining features of senescent cells and explores the fundamental mechanisms underlying senescent cell generation following IRI. We elucidate the pivotal roles of cellular senescence in the transition from IRI-AKI to chronic kidney injury. Furthermore, we discuss emerging therapies targeting cellular senescence, including senolytics and senomorphics, which have shown promising results in both preclinical and clinical settings. These therapies position cellular senescence as a crucial target for the treatment of IRI in the kidneys. Additionally, advancements in single-cell sequencing technology and artificial intelligence-assisted drug screening are expected to accelerate the discovery of novel senescent biomarkers and synotherapeutics, paving the way for optimized and personalized therapeutic interventions.
Humans ; Cellular Senescence/physiology* ; Reperfusion Injury/pathology* ; Acute Kidney Injury/pathology* ; Animals ; Kidney/metabolism* ; Senescence-Associated Secretory Phenotype/physiology*

OBJECTIVES: To investigate the clinical sub-phenotype (SP) of pediatric acute kidney injury (AKI) and their association with clinical outcomes. METHODS: General status and initial values of laboratory markers within 24 hours after admission to the pediatric intensive care unit (PICU) were recorded for children with AKI in the derivation cohort (n=650) and the validation cohort (n=177). In the derivation cohort, a least absolute shrinkage and selection operator (LASSO) regression analysis was used to identify death-related indicators, and a two-step cluster analysis was employed to obtain the clinical SP of AKI. A logistic regression analysis was used to develop a parsimonious classifier model with simplified metrics, and the area under the curve (AUC) was used to assess the value of this model. This model was then applied to the validation cohort and the combined derivation and validation cohort. The association between SPs and clinical outcomes was analyzed with all children with AKI as subjects. RESULTS: In the derivation cohort, two clinical SPs of AKI (SP1 and SP2) were identified by the two-step cluster analysis using the 20 variables screened by LASSO regression, namely SP_d1 group (n=536) and SP_d2 group (n=114). The simplified classifier model containing eight variables (P<0.05) had an AUC of 0.965 in identifying the two clinical SPs of AKI (P<0.001). The validation cohort was clustered into SP_v1 group (n=156) and SP_v2 group (n=21), and the combined derivation and validation cohort was clustered into SP1 group (n=694) and SP2 group (n=133). After adjustment for confounding factors, compared with the SP1 group, the SP2 group had significantly higher incidence rates of multiple organ dysfunction syndrome and death during the PICU stay (P<0.001), and SP2 was significantly associated with the risk of death within 28 days after admission to the PICU (P<0.001). CONCLUSIONS This study establishes a parsimonious classifier model and identifies two clinical SPs of AKI with different clinical features and outcomes.The SP2 group has more severe disease and worse clinical prognosis.
Humans ; Acute Kidney Injury/diagnosis* ; Prognosis ; Male ; Female ; Child ; Child, Preschool ; Phenotype ; Infant ; Logistic Models ; Adolescent

OBJECTIVES: To evaluate the correlation of mean arterial oxygen tension (PaO₂) during the first 24 h following intensive care unit (ICU) admission with mortality in critically ill patients with acute kidney injury (AKI) and determine the optimal PaO₂ threshold for devising oxygen therapy strategies for these patients. METHODS: We collected the clinical data of ICU patients with AKI from the MIMIC-IV database. Based on the optimal first 24-h PaO₂ threshold determined by receiver operating characteristic (ROC) curve analysis and the Youden index maximization principle, we classified the patients into hyperoxia group (with PaO₂ ≥137.029 mmHg) and hypoxemia group (PaO₂<137.029 mm Hg). Multivariable logistic regression and propensity score matching were used to evaluate the correlation of first 24-h PaO₂ levels with in-hospital mortality of the patients. RESULTS: Among the 18 335 patients, 46.7% were in the hyperoxia group, who had an overall mortality rate of 16.9%. The optimal PaO₂ threshold (137.029 mm Hg) had a sensitivity of 78.3%, a specificity of 63.7%, and an AUC of 0.76 (95% CI: 0.74=0.78). Hyperoxia within the first 24 h after ICU admission was associated with a significantly lower in-hospital mortality (OR=0.78) and 90-day mortality (OR=0.77), particularly in stage 1 AKI patients. A non-linear relationship was identified between PaO₂ and mortality of the patients (P<0.001). Kaplan-Meier survival curves indicated a significantly increased 90-day survival rate in the patients in hyperoxia group (P<0.001), who also had shorter durations of mechanical ventilation, less vasopressor use, and shorter lengths of hospital/ICU stay. CONCLUSIONS Maintenance of a PaO₂ level ≥137.029 mmHg within 24 h after ICU admission may improve clinical outcomes of critically ill AKI patients, which underscores the importance of targeted oxygen delivery in ICU care.
Humans ; Acute Kidney Injury/blood* ; Male ; Female ; Middle Aged ; Intensive Care Units ; Aged ; Oxygen/blood* ; Hospital Mortality ; Partial Pressure ; Adult ; Databases, Factual

OBJECTIVES: To investigate the association of serum albumin level after human albumin infusion with 28-day mortality in critically ill patients with acute kidney injury (AKI) and its impact on 90-day outcomes of the patients. METHODS: We conducted a retrospective cohort study based on the MIMIC IV database (2008-2019), including 5918 AKI patients treated with albumin in the ICU. Based on serum albumin levels within 72 h after albumin infusion, the patients were divided into low (<30 g/L), medium (30-35 g/L), and high albumin (>35 g/L) groups. Restricted cubic spline regression and multivariate logistic regression were used to analyze the association of albumin levels with patient mortality, and the results were verified in a external validation cohort consisting of 110 sepsis-induced AKI patients treated in Nanfang Hospital between 2017 and 2022 using survival analysis and multivariate adjustment. RESULTS: In the MIMIC training cohort, multivariate logistic regression showed no significant differences in 28-day mortality of the patients with different albumin levels (P>0.05). However, restricted cubic spline analysis indicated a non-linear dose-response relationship between albumin levels and 28-day mortality (threshold effect: risk increased when albumin levels >3.6 g/dL). Secondary endpoint analysis revealed that the patients with high albumin levels had a shorter duration of mechanical ventilation (P<0.001) but a longer ICU stay (P<0.001). In the validation cohort, albumin levels ≥30 g/L were significantly associated with a reduced 28-day mortality rate (P<0.05). CONCLUSIONS The association between increased serum albumin levels following albumin infusion and 28-day mortality of critically ill patients with AKI exhibits a cohort dependency and can be influenced by multiple factors including disease type and severity, infusion strategies, and statistical methods.
Humans ; Acute Kidney Injury/therapy* ; Critical Illness/mortality* ; Retrospective Studies ; Serum Albumin/analysis* ; Male ; Female ; Intensive Care Units ; Middle Aged ; Logistic Models ; Aged

OBJECTIVES: To investigate the role of ferroptosis in diquat-induced acute kidney injury (AKI) and its molecular mechanisms. METHODS: Transgenic zebrafish models with Tg (Eco.Tshb:EGFP) labeling of the renal tubules and Tg (lyz:dsRed2) labeling of the neutrophils were both divided into control group, gentamicin (positive control) group, diquat poisoning group, ferroptosis inhibitor group. The indicators of kidney injury, inflammatory response, and ferroptosis were examined in the zebrafish, and the changes in expressions of voltage-dependent anion-selective channel protein 1 (VDAC1) and mitochondrial ferritin (FTMT) were detected using Western blotting. RESULTS: AKI induced by diquat exhibited a significant dose-effect relationship, and the severity of injury was proportional to the exposure concentration. Diquat also caused marked oxidative stress and inflammatory responses in the zebrafish models. Rhodamine metabolism assay and HE staining revealed significantly declined glomerular filtration function of the zebrafish as diquat exposure concentration increased. Immunofluorescence staining highlighted significant changes in the expressions of ferroptosis markers GPX4 and FTH1 in zebrafish renal tissues following diquat exposure. In diquat-exposed zebrafish, treatment with ferrostatin-1, a ferroptosis inhibitor, obviously upregulated GPX4 and downregulated FTH1 expressions and improved the metabolic rate of glucan labeled with rhodamine B. Diquat exposure significantly upregulated the expression of VDAC1 and FTMT in zebrafish, and the application of ferrostatin-1 and VBIT-12 (a VDAC1 inhibitor) both caused pronounced downregulation of FTMT expression. CONCLUSIONS Ferroptosis is a critical mechanism underlying diquat-induced AKI, in which VDAC1 and FTMT play important regulatory roles, suggesting their potential as therapeutic target for AKI caused by diquat.
Animals ; Zebrafish ; Ferroptosis/drug effects* ; Acute Kidney Injury/chemically induced* ; Diquat/toxicity* ; Animals, Genetically Modified ; Voltage-Dependent Anion Channel 1/metabolism* ; Ferritins/metabolism* ; Oxidative Stress

Renal ischemia-reperfusion injury (IRI) is a major contributor to acute kidney injury (AKI), leading to substantial morbidity and mortality. Spexin (SPX), a 14-amino acid endogenous peptide involved in metabolic regulation and immune modulation, has not yet been studied in the context of chronic treatment and renal IRI. This study evaluated the effects of exogenous SPX on renal function, histopathological changes, and molecular pathways in both IRI-induced injured and healthy kidneys. Twenty-eight male BALB/c mice were divided into four groups: control, SPX, IRI, and SPX+IRI. IRI was induced by 30 minutes of bilateral renal ischemia followed by 6 hours of reperfusion. Renal injury markers, histopathological changes, inflammatory mediators, apoptotic markers, and fibrosis-related proteins were analyzed. SPX significantly exacerbated IRI-induced kidney injury by activating the Wnt/β-catenin signaling pathway and promoting the upregulation of pro-inflammatory, pro-apoptotic, and pro-fibrotic mediators. It is noteworthy that SPX exerted more severe deleterious nephrotoxic effects in the healthy kidney compared to those observed in the IRI-induced injured kidney. These findings indicate that chronic treatment with SPX administration may have intrinsic pro-inflammatory, pro-apoptotic and fibrotic properties, raising concerns about its therapeutic potential. Further research is needed to clarify its physiological role and therapeutic implications in kidney diseases.
Animals ; Reperfusion Injury/chemically induced* ; Male ; Mice, Inbred BALB C ; Mice ; Acute Kidney Injury/metabolism* ; Kidney/blood supply* ; Peptide Hormones/adverse effects* ; Apoptosis/drug effects* ; Wnt Signaling Pathway/drug effects* ; Disease Models, Animal

OBJECTIVE: To investigate the effects of using different filters in continuous renal replacement therapy (CRRT) on the mortality, inflammatory mediator level and hemodynamics in patients with sepsis-associated acute kidney injury (SA-AKI). METHODS: A prospective study was conducted. The patients with SA-AKI undergoing first CRRT admitted to the critical care medicine department of General Hospital of Ningxia Medical University from August 2022 to October 2023 were enrolled as the study objects, and they were divided into observation group and control group by random number table method. All patients received routine treatment including anti-infection, optimized volume management and organ function support. On this basis, the observation group was treated with oXiris filter for CRRT, while the control group was treated with ordinary filter for CRRT, and the first treatment time was ≥ 36 hours. General data of the two groups were collected and compared. At the same time, the inflammatory indicators [high-sensitivity C-reactive protein (hs-CRP), procalcitonin (PCT), interleukin-6 (IL-6)], sequential organ failure assessment (SOFA) score, mean arterial pressure (MAP), blood lactic acid (Lac), noradrenaline dosage and other related indicators were collected before CRRT treatment and 24 hours and 48 hours after treatment, and the 7-day and 28-day mortality of patients were recorded. RESULTS: Finally, 65 patients were enrolled, including 30 in the observation group and 35 in the control group. There were no significant differences in baseline data including age, gender, acute kidney injury (AKI) stage and infection source between the two groups. The 7-day mortality of observation group was significantly lower than that of control group [16.7% (5/30) vs. 42.9% (15/35), P < 0.05]. There was no significant difference in 28-day mortality between the observation group and the control group [36.7% (11/30) vs. 54.3% (19/35), P > 0.05]. There were no significant differences in inflammation indicators, SOFA score, MAP, Lac and norepinephrine dosage before treatment between the two groups. After 24-hour and 48-hour treatment, the hemodynamics of the two groups were stable compared with before treatment, the inflammatory indicators, SOFA score, Lac and norepinephrine dosage were reduced to varying degrees, and MAP was significantly increased. In the observation group, hs-CRP, PCT, IL-6, SOFA score, MAP, and norepinephrine dosage showed statistical significance at 24 hours after treatment as compared with before treatment [hs-CRP (mg/L): 125.0 (105.0, 171.2) vs. 280.5 (213.2, 313.8), PCT (μg/L): 51.0 (20.0, 62.8) vs. 71.0 (10.8, 100.0), IL-6 (ng/L): 1 762.2 (300.8, 4 327.5) vs. 4 447.5 (630.4, 5 000.0), SOFA score: 13.0 (12.0, 14.0) vs. 16.0 (15.0, 17.0), MAP (mmHg, 1 mmHg ≈ 0.133 kPa): 79.00±12.87 vs. 65.20±11.70, norepinephrine dosage (μg×kg^-1×min^-1): 0.82±0.33 vs. 1.63±0.51, all P < 0.05]. In the control group, PCT and MAP showed statistical significance after 48 hours of treatment as compared with before treatment. Compared with the control group, hs-CRP, SOFA score and norepinephrine dosage after 48 hours of treatment in the observation group were significantly decreased [hs-CRP (mg/L): 87.2 (74.2, 126.0) vs. 157.0 (88.0, 200.0), SOFA score: 11.0 (10.0, 12.0) vs. 12.0 (10.0, 14.0), norepinephrine dosage (μg×kg^-1×min^-1): 0.51±0.37 vs. 0.81±0.58, all P < 0.05], MAP was significantly increased (mmHg: 82.00±8.71 vs. 77.77±7.80, P < 0.05). CONCLUSION In the treatment of CRRT, oXiris filter can reduce the short-term mortality of SA-AKI patients, lower inflammatory mediators levels and improve hemodynamics, showing therapeutic advantages over conventional filters.
Humans ; Acute Kidney Injury/etiology* ; Sepsis/therapy* ; Prospective Studies ; Interleukin-6 ; Continuous Renal Replacement Therapy/methods* ; C-Reactive Protein ; Male ; Female ; Middle Aged ; Hemodynamics ; Procalcitonin ; Aged

Sepsis is a life-threatening organ dysfunction syndrome caused by a dysregulated host response to infection. Septic acute kidney injury (SAKI) is one of the most common complications of sepsis, and the occurrence of acute kidney injury (AKI) indicates that the patient's condition is critical with a poor prognosis. The traditional view holds that the main mechanism of SAKI is the reduction of renal blood flow, inadequate renal perfusion, inflammatory response, and microcirculatory dysfunction caused by sepsis, which subsequently leads to ischemia and necrosis of renal tubular cells. Recent research findings indicate that processes such as autophagy and other forms of programmed cell death play an increasingly important role. Autophagy is a programmed intracellular degradation process and is a form of programmed cell death. Cells degrade their cytoplasmic components via lysosomes, breaking down and recycling intracellular constituents to meet their metabolic needs, maintain intracellular homeostasis, and renew organelles. During SAKI, autophagy plays a crucial protective role through various mechanisms, including regulating inflammation and immune responses, clearing damaged organelles, and maintaining stability in the intracellular environment. In recent years, the role of autophagy in the pathogenesis and treatment of SAKI has received widespread attention. Research has confirmed that various intracellular signaling pathways and signaling molecules targeting autophagy [such as mammalian target of rapamycin (mTOR) signaling pathway, AMP-activated protein kinase (AMPK) signaling pathway, nuclear factor-κB (NF-κB) signaling pathway, and Sirtuins (SIRT), autophagy associated factor Beclin-1, and Toll-like receptor (TLR)] are involved in the development of SAKI. Due to the complex pathogenesis of SAKI, current treatment strategies include fluid management, infection control, maintenance of internal environment balance, and renal replacement therapy; however, the mortality remains high. In recent years, it has been found that autophagy plays a critical protective role in sepsis-mediated AKI. As a result, an increasing number of drugs are being developed to alleviate SAKI by regulating autophagy. This article reviews the latest advances in the role of autophagy in the pathogenesis and treatment of SAKI, with the aim of providing insights for the development of new drugs for SAKI patients.
Humans ; Acute Kidney Injury/etiology* ; Autophagy ; Sepsis/complications* ; Signal Transduction

OBJECTIVE: To investigate the predictive value of inflammatory indicator and serum cystatin C (Cys C) for the prognosis of patients with sepsis-associated acute kidney injury (SA-AKI). METHODS: A prospective observational study was conducted. Patients with SA-AKI admitted to the intensive care unit (ICU) of the General Hospital of Ningxia Medical University from January 2022 to December 2023 were selected as the study subjects. General patient data, sequential organ failure assessment (SOFA), acute physiology and chronic health evaluation II (APACHE II), inflammatory indicator, and serum Cys C levels were collected. The 28-day survival status of the patients was observed. A multivariate Logistic regression model was used to analyze the risk factors affecting the poor prognosis of SA-AKI patients. Receiver operator characteristic curve (ROC curve) was plotted to evaluate the predictive efficacy of each risk factor for the prognosis of SA-AKI patients. RESULTS: A total of 111 SA-AKI patients were included, with 65 patients (58.6%) in the survival group and 46 patients (41.4%) in the death group. The SOFA score, APACHE II score, interleukin-6 (IL-6), procalcitonin (PCT), hypersensitive C-reactive protein (hs-CRP), and serum Cys C levels in the death group were significantly higher than those in the survival group [SOFA score: 15.00 (14.00, 17.25) vs. 14.00 (11.00, 16.00), APACHE II score: 26.00 (23.75, 28.00) vs. 23.00 (18.50, 28.00), IL-6 (ng/L): 3 731.00±1 573.61 vs. 2 087.93±1 702.88, PCT (μg/L): 78.19±30.35 vs. 43.56±35.37, hs-CRP (mg/L): 266.50 (183.75, 326.75) vs. 210.00 (188.00, 273.00), serum Cys C (mg/L): 2.01±0.61 vs. 1.62±0.50, all P < 0.05]. Multivariate Logistic regression analysis showed that SOFA score [odds ratio (OR) = 1.273, 95% confidence interval (95%CI) was 1.012-1.600, P = 0.039], IL-6 (OR = 1.000, 95%CI was 1.000-1.001, P = 0.043), PCT (OR = 1.018, 95%CI was 1.002-1.035, P = 0.030), and Cys C (OR = 4.139, 95%CI was 1.727-9.919, P = 0.001) were independent risk factors affecting the 28-day prognosis of SA-AKI patients. ROC curve analysis showed that the area under the curve (AUC) of SOFA score, IL-6, PCT, and Cys C in predicting the 28-day prognosis of SA-AKI patients were 0.682 (95%CI was 0.582-0.782, P = 0.001), 0.753 (95%CI was 0.662-0.843, P < 0.001), 0.765 (95%CI was 0.677-0.854, P < 0.001), and 0.690 (95%CI was 0.583-0.798, P = 0.001), respectively. The combined predictive value of these four indicators for the prognosis of SA-AKI patients were superior to that of any single indicator, with an AUC of 0.847 (95%CI was 0.778-0.916, P < 0.001), a sensitivity of 95.7%, and a specificity of 56.9%. CONCLUSION The combination of SOFA score, IL-6, PCT, and Cys C provides a reliable predictive value for the prognosis of SA-AKI patients.
Humans ; Acute Kidney Injury/mortality* ; APACHE ; C-Reactive Protein ; Cystatin C/blood* ; Interleukin-6/blood* ; Logistic Models ; Predictive Value of Tests ; Procalcitonin/blood* ; Prognosis ; Prospective Studies ; Risk Factors ; ROC Curve ; Sepsis/mortality*