Aldehyde Dehydrogenase 2 Ameliorates LPS-Induced Acute Kidney Injury through Detoxification of 4-HNE and Suppression of the MAPK Pathway.

Lipopolysaccharide (LPS)-induced septic acute kidney injury (AKI) is determined as a devastating organ dysfunction elicited by an inappropriate response to infection with high morbidity and mortality rates. Previous evidence has illustrated an indispensable role of mitochondrial aldehyde dehydrogenase 2 (ALDH2) in the pathogenesis of sepsis-induced multiorgan abnormalities. Specifically, this study investigated the potential role of ALDH2 in sepsis-induced AKI. After LPS administration, we observed a significant decline in renal function, increased inflammatory cytokines, oxidative stress, 4-hydroxy-2-nonenal (4-HNE) accumulation, and apoptosis via MAPK activation in ALDH2-/- mice; in contrast, pretreatment with Alda-1 (an ALDH2 activator) alleviated the LPS-induced dysfunctions in mice. Moreover, in vitro analysis revealed that ALDH2 overexpression in mouse tubular epithelial cells (mTECs) improved the inflammatory response, oxidative stress, 4-HNE accumulation, and apoptosis via MAPK inhibition, whereas ALDH2 knockdown in mTECs aggravated these parameters via MAPK activation. Therefore, ALDH2 may protect against LPS-induced septic AKI by suppressing 4-HNE/MAPK pathway.

Case report: Implantable cardioverter-defibrillator implantation with optimal medical treatment for lethal ventricular arrhythmia caused by recurrent coronary artery spasm due to tyrosine kinase inhibitors.

Coronary artery spasm (CAS) may induce lethal ventricular arrhythmia due to severe and prolonged vessel constriction. Tyrosine kinase inhibitors are associated with the occurrence of CAS. Optimal medical treatment is the first-line therapeutic option for the management of CAS, whereas patients who experienced aborted sudden cardiac death (SCD) may benefit from implantable cardioverter-defibrillator (ICD) implantation. We report a case of a 63-year-old Chinese man receiving tyrosine kinase inhibitor treatment for liver cancer who presented with recurrent chest discomfort and syncope with an elevation of high-sensitivity troponin T. Emergent coronary angiography showed sub-total occlusion of the left anterior descending artery without other signs of CAS. Percutaneous transluminal coronary angioplasty with a drug-coated balloon was performed successfully with the guidance of intravascular ultrasound. After 5 months, the patient returned to the emergency room for chest discomfort and another episode of syncope. The electrocardiogram showed ST-segment elevation in the inferior and V5-V6 leads compared to the previous event. Coronary angiography was repeated immediately and showed significant luminal stenosis at the midportion of the right coronary artery (RCA), whereas, after administration of intracoronary nitroglycerine, a remarkable recovery of RCA patency was noticed. A diagnosis of CAS was made, and soon after that, the patient rapidly developed ventricular arrhythmia in the coronary care unit. After successful resuscitation, the patient recovered completely and received long-acting calcium channel blockers as well as nitrates therapy. ICD implantation was performed considering the high risk of recurrence of life-threatening ventricular arrhythmia. During the follow-up period, the patient has been free of angina, syncope, or ventricular arrhythmia, and ICD interrogation showed no ventricular tachycardia or ventricular fibrillation. We first reported the case of a patient with CAS induced by regorafenib treatment complicated with severe atherosclerotic coronary disease who survived from sudden cardiac arrest. ICD implantation is indicated in patients who experienced aborted SCD for the prevention of the next lethal ventricular arrhythmia.

Loss of ALDH2 aggravates mitochondrial biogenesis disorder in cardiac myocytes induced by TAC.

Heart failure is one of the major fatal diseases and mitochondrial biogenesis is an important compensatory mechanism in the process of heart failure. Aldehyde dehydrogenase 2(ALDH2) is an important endogenous cardiac protective factor in mitochondria, but its role in mitochondrial biogenesis of cardiomyocytes remains unknown. In our study, transverse aorta constriction(TAC)-induced heart failure model was established in ALDH2-/- mice and wild-type mice. The cardiac function was examined by echocardiography at 4 weeks after operation. The myocardial tissue was stained by HE. The mitochondria morphology was observed using electron microscope, and the ATP content, Sirt1,PGC-1α and NRF1 expression were measured. Compared with wild-type mice, the cardiac function of ALDH2 -/- mice decreased significantly at 4 weeks after TAC. The proportion of mitochondrial area and mitochondrial crest/mitochondrial ratio decreased in the ALDH2-/- group after TAC. The ATP content decreased in ALDH2 -/- mice at 4 weeks after TAC. In the meantime, the expression of PGC-1α,Sirt 1 and NRF1 decreased in the ALDH2-/- TAC group compared with wild type TAC group.Neonatal rat cardiomyocytes were cultured and stretched. Cardiomyocytes were treated with the activator of ALDH2(Alda-1), Sirt1-SiRNA and PGC-1α-siRNA, respectively. The mitochondrial structure of cardiomyocytes was observed by transmission electron microscopy. The levels of PGC-1α,NRF-1 and Tfam were measured by Western blot.Mitochondrial biogenesis was enhanced in stretch cardiomyocytes treated with Alda-1.When cardiomyocytes were treated with Sirt1-SiRNA or PGC1α-SiRNA, the effect of Alda-1 in promoting mitochondrial biogenesis was attenuated.Therefore, these results suggested that the loss of ALDH2 aggravates mitochondrial biogenesis disorder in cardiac myocytes induced by TAC. Alda-1 could promote mitochondrial biogenesis in stretched cardiomyocytes, and this effect depends on Sirt1/PGC-1α pathway.

Aldehyde Dehydrogenase 2 (ALDH2) Elicits Protection against Pulmonary Hypertension via Inhibition of ERK1/2-Mediated Autophagy.

Pulmonary hypertension (PH) is caused by chronic hypoxia that induces the migration and proliferation of pulmonary arterial smooth muscle cells (PASMCs), eventually resulting in right heart failure. PH has been related to aberrant autophagy; however, the hidden mechanisms are still unclear. Approximately 40% East Asians, equivalent to 8% of the universal population, carry a mutation in Aldehyde dehydrogenase 2 (ALDH2), which leads to the aggregation of noxious reactive aldehydes and increases the propensity of several diseases. Therefore, we explored the potential aspect of ALDH2 in autophagy associated with PH. In vitro mechanistic studies were conducted in human PASMCs (HPASMCs) after lentiviral ALDH2 knockdown and treatment with platelet-derived growth factor-BB (PDGF-BB). PH was induced in wild-type (WT) and ALDH2-knockout (ALDH2-/-) mice using vascular endothelial growth factor receptor inhibitor SU5416 under hypoxic conditions (HySU). Right ventricular function was assessed using echocardiography and invasive hemodynamic monitoring. Histological and immunohistochemical analyses were performed to evaluate pulmonary vascular remodeling. EdU, transwell, and wound healing assays were used to evaluate HPASMC migration and proliferation, and electron microscopy and immunohistochemical and immunoblot assays were performed to assess autophagy. The findings demonstrated that ALDH2 deficiency exacerbated right ventricular pressure, hypertrophy, fibrosis, and right heart failure resulting from HySU-induced PH. ALDH2-/- mice exhibited increased pulmonary artery muscularization and 4-hydroxynonenal (4-HNE) levels in lung tissues. ALDH2 knockdown increased PDGF-BB-induced PASMC migration and proliferation and 4-HNE accumulation in vitro. Additionally, ALDH2 deficiency increased the number of autophagosomes and autophagic lysosomes together with autophagic flux and ERK1/2-Beclin-1 activity in lung tissues and PASMCs, indicating enhanced autophagy. In conclusion, the study shows that ALDH2 has a protective role against the migration and proliferation of PASMCs and PH, possibly by regulating autophagy through the ERK1/2-Beclin-1 pathway.

Nuclear farnesoid X receptor attenuates acute kidney injury through fatty acid oxidation.

Acute kidney injury (AKI) is a life-threatening condition that is one of most common side effects of cisplatin therapy. Fatty acid oxidation (FAO) is the main source of energy production in kidney proximal tubular epithelial cells (PTECs) but it is inhibited in AKI. Recent work demonstrated that activation of the farnesoid X receptor (FXR) protects against AKI, but the underlying mechanism remains elusive. Using a model of cisplatin-induced AKI, we found that FXR and FAO-related genes were remarkably downregulated while kidney lipid accumulated. Proximal tubule-specific or whole body FXR knockout worsened, while pharmacological activation attenuated these effects. Conversely, FXR knockout in non-proximal tubules did not. RNA-sequencing of PTECs demonstrated increased transcripts involved in metabolic pathways in cells overexpressing FXR versus control after cisplatin treatment, specifically transcripts associated with FAO and peroxisome proliferator-activated receptor-γ (PPARγ) signaling. Furthermore, FXR overexpression or activation improved FAO and inhibited intracellular lipid accumulation in cisplatin-treated cells. In vivo studies have shown that pharmacological activation of PPARγ can prevent cisplatin-induced lipid accumulation, kidney tubule injury and kidney function decline. However, inhibition of PPARγ eliminated the protective effects of FXR compared to control mice during the cisplatin treatment phase and after ischemia-reperfusion injury. Consistent with findings in vivo, FXR/PPARγ reduced lipid accumulation by improving FAO in cisplatin-treated cells. Furthermore, the inhibition of carnitine palmitoyltransferase 1α abolished the protective effect of FXR in cisplatin-treated mice. Thus, FXR improves FAO and reduced lipid accumulation via PPARγ in PTECs of the kidney. Hence, reconstruction of the FXR/PPARγ/FAO axis may be a novel therapeutic strategy for preventing or treating AKI.

Association between sleep duration and quality with rapid kidney function decline and development of chronic kidney diseases in adults with normal kidney function: The China health and retirement longitudinal study.

Research have shown that sleep is associated with renal function. However, the potential effects of sleep duration or quality on kidney function in middle-aged and older Chinese adults with normal kidney function has rarely been studied. Our study aimed to investigate the association of sleep and kidney function in middle-aged and older Chinese adults. Four thousand and eighty six participants with an eGFR ≥60 ml/min/1.73 m2 at baseline were enrolled between 2011 and 2015 from the China Health and Retirement Longitudinal Study. Survey questionnaire data were collected from conducted interviews in the 2011. The eGFR was estimated from serum creatinine and/or cystatin C using the Chronic Kidney Disease Epidemiology Collaboration equations (CKD-EPI). The primary outcome was defined as rapid kidney function decline. Secondary outcome was defined as rapid kidney function decline with clinical eGFR of <60 ml/min/1.73 m2 at the exit visit. The associations between sleep duration, sleep quality and renal function decline or chronic kidney disease (CKD) were assessed based with logistic regression model. Our results showed that 244 (6.0%) participants developed rapid decline in kidney function, while 102 (2.5%) developed CKD. In addition, participants who had 3-7 days of poor sleep quality per week had higher risks of CKD development (OR 1.86, 95% CI 1.24-2.80). However, compared with those who had 6-8 h of night-time sleep, no significantly higher risks of rapid decline in kidney function was found among those who had <6 h or >8 h of night time sleep after adjustments for demographic, clinical, or psychosocial covariates. Furthermore, daytime nap did not present significant risk in both rapid eGFR decline or CKD development. In conclusion, sleep quality was significantly associated with the development of CKD in middle-aged and older Chinese adults with normal kidney function.

Perilipin 2 Impacts Acute Kidney Injury via Regulation of PPARα.

Renal ischemia-reperfusion (I/R) can induce oxidative stress and injury via the generation of reactive oxygen species (ROS). Renal proximal tubular cells are susceptible to oxidative stress, and the dysregulation of renal proximal tubular cellular homeostasis can damage cells via apoptotic pathways. A recent study showed that the generation of ROS can increase perilipin 2 (Plin2) expression in HepG2 cells. Some evidence has also demonstrated the association between Plin2 expression and renal tumors. However, the underlying mechanism of Plin2 in I/R-induced acute kidney injury (AKI) remains elusive. Here, using a mouse model of I/R-induced AKI, we found that ROS generation was increased and the expression of Plin2 was significantly upregulated. An in vitro study further revealed that the expression of Plin2, and the generation of ROS were significantly upregulated in primary tubular cells treated with hydrogen peroxide. Accordingly, Plin2 knockdown decreased apoptosis in renal proximal tubular epithelial cells treated with hydrogen peroxide, which depended on the activation of peroxisome proliferator-activated receptor α (PPARα). Overall, the present study demonstrated that Plin2 is involved in AKI; knockdown of this marker might limit apoptosis via the activation of PPARα. Consequently, the downregulation of Plin2 could be a novel therapeutic strategy for AKI.

Hemodilution is associated with underestimation of serum creatinine in cardiac surgery patients: a retrospective analysis.

BACKGROUND: Fluid overload is related to the development and prognosis of cardiac surgery-associated acute kidney injury (CSA-AKI). The study is to investigate the influence of serum creatinine (SCr) corrected by fluid balance on the prognosis of patients with cardiac surgery. METHODS: A retrospective study was conducted in 1334 patients who underwent elective cardiac surgery from January 1 to December 31, 2015. Kidney Disease: Improving Global Outcomes (KDIGO) criteria for AKI were applied to identify CSA-AKI. SCr was measured every 24 h during ICU period and was accordingly adjusted for cumulative fluid balance. Changes in SCr, defined as ∆Crea, were determined by difference between before and after adjustment for cumulative fluid balance. All patients were then divided into three groups: underestimation group (∆Crea ≥ P75), normal group (P25 < ∆Crea < P75) and overestimation group (∆Crea ≤ P25). RESULTS: The incidence of AKI increased from 29.5% to 31.8% after adjustment for fluid balance. Patients in underestimation group showed prolonged length of ICU stay compared with normal group and overestimation group (3.2 [1.0-4.0] vs 2.1 [1.0-3.0] d, P < 0.001; 3.2  [1.0-4.0] vs 2.3 [1.0-3.0] d, P < 0.001). Length of hospital stay and mechanical ventilation dependent days in underestimation group were significantly longer than normal group (P < 0.001). Multivariate analysis showed age, baseline SCr and left ventricular ejection fraction were independently associated with underestimation of creatinine. CONCLUSIONS: Cumulative fluid balance after cardiac surgery disturbs accurate measurement of serum creatinine. Patients with underestimation of SCr were associated with poor prognosis.

Postoperative diastolic perfusion pressure is associated with the development of acute kidney injury in patients after cardiac surgery: a retrospective analysis.

BACKGROUND: We aimed to investigate the relationship between the perioperative hemodynamic parameters and the occurrence of cardiac surgery-associated acute kidney injury. METHODS: A retrospective study was performed in patients who underwent cardiac surgery at a tertiary referral teaching hospital. Acute kidney injury was determined according to the KDIGO criteria. We investigated the association between the perioperative hemodynamic parameters and cardiac surgery-associated acute kidney injury to identify the independent hemodynamic predictors for acute kidney injury. Subgroup analysis was further performed in patients with chronic hypertension. RESULTS: Among 300 patients, 29.3% developed acute kidney injury during postoperative intensive care unit period. Multivariate logistic analysis showed the postoperative nadir diastolic perfusion pressure, but not mean arterial pressure, central venous pressure and mean perfusion pressure, was independently linked to the development of acute kidney injury after cardiac surgery (odds ratio 0.945, P = 0.045). Subgroup analyses in hypertensive subjects (n = 91) showed the postoperative nadir diastolic perfusion pressure and peak central venous pressure were both independently related to the development of acute kidney injury (nadir diastolic perfusion pressure, odds ratio 0.886, P = 0.033; peak central venous pressure, odds ratio 1.328, P = 0.010, respectively). CONCLUSIONS: Postoperative nadir diastolic perfusion pressure was independently associated with the development of cardiac surgery-associated acute kidney injury. Furthermore, central venous pressure should be considered as a potential hemodynamic target for hypertensive patients undergoing cardiac surgery.

Early Postoperative Serum Creatinine Adjusted for Fluid Balance Precisely Predicts Subsequent Acute Kidney Injury After Cardiac Surgery.

OBJECTIVES: Cumulative fluid overload may influence acute kidney injury (AKI) diagnosis due to the dilution effect. The authors hypothesized a small increase of early postoperative serum creatinine (SCr) adjusted for fluid balance might have superior discrimination ability in subsequent AKI prediction. DESIGN: Retrospective analyses. SETTING: A single-center study in a university hospital. PARTICIPANTS: The study comprised 1,016 adult patients who underwent elective isolated or combined valve surgery in 2015. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Baseline characteristics, intraoperative parameters, and intraoperative and postoperative fluid balance were collected through a retrospective chart review. Early postoperative SCr level was drawn within 12 hours of surgical completion and then measured daily. Early relative changes of SCr were categorized as a cutoff value of 10% with or without adjustment for cumulative fluid balance. Kidney Disease: Improving Global Outcomes criteria were used to detect AKI. Logistic analyses were performed to determine risk factors for subsequent AKI with the inclusion of measured or fluid-adjusted early relative changes of SCr, respectively. In this study, 355 patients (34.9%) developed AKI. Multivariate logistic analyses showed age, weight, European System for Cardiac Operative Risk Evaluation II, and cardiopulmonary bypass duration were associated independently with the development of AKI. Model discrimination for AKI prediction was improved significantly when the addition of measured (area under the receiver operating characteristic curve [AUROC] 0.830) and fluid-adjusted early changes of SCr to the basic model (AUROC 0.850). CONCLUSIONS: Early fluid-adjusted relative changes of SCr could improve the predictive ability for subsequent development of AKI in valve surgery patients.

Usefulness of High Estimated Pulmonary Artery Systolic Pressure to Predict Acute Kidney Injury After Cardiac Valve Operations.

High estimated pulmonary artery systolic pressure (ePASP) has been established as a detrimental predictor for adverse outcomes in patients with chronic kidney disease. However, the relation between preoperative high ePASP and the development of cardiac surgery associated acute kidney injury (CSA-AKI) has not been validated. We performed a retrospective cohort study of adult patients who underwent valve surgery in 2015 at Zhongshan Hospital, Fudan University. Right ventricular systolic pressure, a surrogate for pulmonary systolic pressure, was estimated in the study group of 1056 patients by preoperative echocardiography. CSA-AKI was defined based on the Kidney Disease Improving Global Outcomes criteria. The relation between preoperative ePASP and CSA-AKI was demonstrated with the use of multivariate analysis after adjusting for potential risk factors for CSA-AKI. Of these patients, preoperative ePASP was 44.5 ± 14.9 mm Hg. 401 (38%) patients developed CSA-AKI in which 73 patients (6.9%) suffered from severe AKI (stage II and III). Multivariate analysis showed that preoperative ePASP was independently associated with CSA-AKI (odds ratio per 10 mm Hg increment, 1.099; 95% confidence interval, 1.003 to 1.204; p = 0.042). Preoperative ePASP more than 60 mm Hg was found to be linked with the increasing incidence of AKI by 62% and in-hospital mortality by over 300%, but not linked with severe AKI or renal replacement therapy. In conclusion, an increase in preoperative ePASP was independently and significantly associated with the development of CSA-AKI in patients who underwent valve surgery. Such relation between preoperative ePASP and CSA-AKI could provide a novel therapeutic target against prevention of AKI.

NLRP3 inflammasome mediates chronic intermittent hypoxia-induced renal injury implication of the microRNA-155/FOXO3a signaling pathway.

Chronic intermittent hypoxia (CIH), as the foremost pathophysiological change of obstructive sleep apnea (OSA), contributes to continued deterioration in renal function. Nucleotide-binding domain like receptor protein 3 (NLRP3) inflammasome is a multiprotein complex that triggers innate immune responses to infection and cell stress through activation of caspase-1 and maturation of inflammatory pro-interleukin-1ß cytokine. Emerging evidence indicates that inhibition of the NLRP3 inflammasome ameliorates renal injury. Nevertheless, it is uncertain whether NLRP3 inflammasome participates in CIH-induced renal injury. The molecular mechanisms modulating NLRP3 inflammasome activation remain to be elucidated. Compared with wild-type mice, NLRP3 knockout mice dramatically protected them from kidney injury, as indicated by the restoration of creatinine levels, lessened histopathological alterations, and the suppression of macrophages infiltration stained with F4/80. NLRP3 deficiency notably reversed CIH-induced oxidative stress (malondialdehyde and superoxide dismutase), concomitantly with the abrogated apoptosis-related proteins and proinflammatory signaling pathway. Consistently, NLRP3-deficient tubular cells remarkably inhibited reactive oxygen species generation and NLRP3 inflammasome activation. Furthermore, our study revealed that microRNA-155 (miR-155) was augmented in the renal tissue and HK-2 cells exposed to CIH. In addition, we investigated the role of miR-155 in the regulation of NLRP3 inflammasome. Inhibition of miR-155 suppressed the CIH-induced NLRP3 inflammasome activation in renal tubular cells, whereas overexpression of miR-155 promoted oxidation and enhanced NLRP3 pathway. Collectively, we demonstrated that miR-155 might be a positive-regulator of NLRP3 pathway by inhibiting the targeted FOXO3a gene. These results established a link between the miR-155/FOXO3a pathway and the NLRP3 inflammasome, suggesting pharmacological blockage of NLRP3 as a potential therapeutic strategy for OSA-associated chronic kidney disease.

Urinary TIMP-2 and IGFBP7 for the prediction of acute kidney injury following cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) following cardiac surgery is common and associated with poor patient outcomes. Early risk assessment for development of AKI remains a challenge. The combination of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) has been shown to be an excellent predictor of AKI following cardiac surgery, but reported studies are for predominately non-Asian populations. METHODS: Adult patients were prospectively enrolled at Zhongshan hospital in Shanghai, China. The primary analysis was prediction of AKI and stage 2-3 AKI by [TIMP-2]*[IGFBP7] measured 4 h after postoperative ICU admission assessed using receiver operating characteristic curve (ROC) analysis. Kinetics of [TIMP-2]*[IGFBP7] following ICU admission were also examined. RESULTS: We prospectively enrolled 57 cardiac surgery patients, of which 20 (35%) developed AKI and 6 (11%) developed stage 2-3 AKI. The area under the ROC curve (AUC) of [TIMP-2]*[IGFBP7] at 4 h after ICU admission was 0.80 (95% confidence interval (CI): 0.68-0.91) for development of AKI and 0.83 (95% CI: 0.69-0.96) for development of stage 2-3 AKI. Urinary [TIMP-2]*[IGFBP7] values at 4 h after ICU admission were significantly (P < 0.001) higher in patients who developed AKI than in patients who did not develop AKI (mean (standard error) of 1.08 (0.34) (ng/mL)2/1000 and 0.29 (0.05) (ng/mL)2/1000, respectively). The time-profile of [TIMP-2]*[IGFBP7] suggests the markers started to elevate by the time of ICU admission in patients who developed AKI and either decreased or remained flat in patients without AKI. CONCLUSION: The combination of urinary TIMP-2 and IGFBP7 4 h after postoperative ICU admission identifies patients at risk for developing AKI, not just stage 2-3 AKI following cardiac surgery.

Dynamic Predictive Scores for Cardiac Surgery-Associated Acute Kidney Injury.

BACKGROUND: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication with a poor prognosis. In order to identify modifiable perioperative risk factors for AKI, which existing risk scores are insufficient to predict, a dynamic clinical risk score to allow clinicians to estimate the risk of CSA-AKI from preoperative to early postoperative periods is needed. METHODS AND RESULTS: A total of 7233 cardiac surgery patients in our institution from January 2010 to April 2013 were enrolled prospectively and distributed into 2 cohorts. Among the derivation cohort, logistic regression was used to analyze CSA-AKI risk factors preoperatively, on the day of ICU admittance and 24 hours after ICU admittance. Sex, age, valve surgery combined with coronary artery bypass grafting, preoperative NYHA score >2, previous cardiac surgery, preoperative kidney (without renal replacement therapy) disease, intraoperative cardiopulmonary bypass application, intraoperative erythrocyte transfusions, and postoperative low cardiac output syndrome were identified to be associated with CSA-AKI. Among the other 1152 patients who served as a validation cohort, the point scoring of risk factor combinations led to area under receiver operator characteristics curves (AUROC) values for CSA-AKI prediction of 0.74 (preoperative), 0.75 (on the day of ICU admission), and 0.82 (postoperative), and Hosmer-Lemeshow goodness-of-fit tests revealed a good agreement of expected and observed CSA-AKI rates. CONCLUSIONS: The first dynamic predictive score system, with Kidney Disease: Improving Global Outcomes (KDIGO) AKI definition, was developed and predictive efficiency for CSA-AKI was validated in cardiac surgery patients.