Distant organ dysfunction in acute kidney injury

Nomogram risk prediction model for acute respiratory distress syndrome following acute kidney injury

Background

Acute respiratory distress syndrome (ARDS), a severe form of respiratory failure, can be precipitated by acute kidney injury (AKI), leading to a significant increase in mortality among affected patients. This study aimed to identify the risk factors for ARDS and construct a predictive nomogram.

Methods

We conducted a retrospective analysis of 1,241 AKI patients admitted to the Second Hospital of Shanxi Medical University from August 25, 2016, to December 31, 2023. The patients were divided into a study cohort (1,012 cases, including 108 with ARDS) and a validation cohort (229 cases, including 23 with ARDS). Logistic regression analysis was employed to identify the risk factors for ARDS, which were subsequently incorporated into the development of a nomogram. The predictive performance of the nomogram was assessed by AUC, calibration plots, and decision curve analyses, with external validation also performed.

Results

Six risk factors were identified and included in the nomogram: older age (OR = 1.020; 95%CI = 1.005-1.036), smoking history (OR = 1.416; 95%CI = 1.213-1.811), history of diabetes mellitus (OR = 1.449; 95%CI = 1.202-1.797), mean arterial pressure (MAP; OR = 1.165; 95%CI = 1.132-1.199), higher serum uric acid levels (OR = 1.002; 95%CI = 1.001-1.004), and higher AKI stage [(stage 1: reference), (stage 2: OR = 11.863; 95%CI = 4.850-29.014), (stage 3: OR = 41.398; 95%CI = 30.840-52.731)]. The AUC values were 0.951 in the study cohort and 0.959 in the validation cohort. Calibration and decision curve analyses confirmed the accuracy and clinical utility of the nomogram.

Conclusion

The nomogram, which integrates age, smoking history, diabetes mellitus history, MAP, and AKI stage, predicts the risk of ARDS in patients with AKI. This tool may aid in early detection and facilitate clinical decision-making.

NSUN3 Aggravates Sepsis-Associated Acute Kidney Injury by Stabilising TIFA mRNA Through m5C

BACKGROUND

Acute kidney injury (AKI) is a common complication of sepsis and also a risk factor for progression of chronic kidney disease. NOP2/Sun RNA methyltransferase 3 (NSUN3) is involved in the regulation of sepsis progression. However, the mechanism by which NSUN3 regulates sepsis-associated AKI (SA-AKI) remains unclear.

METHODS

SA-AKI mouse model and lipopolysaccharide (LPS)-induced injury model in HK-2 cells were constructed. Haematoxylin-eosin staining, quantitative polymerase chain reaction (qPCR), western blotting, cell counting kit 8, flow cytometry, 2',7'-dichlorofluorescein diacetate, enzyme-linked immunosorbent assay, methylation RNA immunoprecipitation-qPCR, actinomycin D and TdT-mediated dUTP Nick-End Labelling staining assays were utilised to explore the expression and related mechanism of NSUN3 in the SA-AKI models.

RESULTS

The expression of NSUN3 and tumour necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA) was upregulated in mice with SA-AKI and LPS-induced HK-2 cells. Knockdown of NSUN3 inhibited LPS-induced injury in HK-2 cells. Mechanically, NSUN3 increased TIFA mRNA stability and upregulated its expression through m5C modification. Moreover, knockdown of NSUN3 was found to alleviate LPS-induced HK-2 cell injury and SA-AKI in mice by reducing TIFA expression.

CONCLUSION

NSUN3 aggravates SA-AKI by stabilising TIFA mRNA through m5C, indicating that NSUN3 may be a biomarker for SA-AKI.

Incidence, risk factors, and outcomes of acute liver injury in hospitalized adults with acute kidney injury: a large multicenter study

BACKGROUND

Acute kidney injury (AKI) and acute liver injury (ALI) were associated with poor outcomes during hospitalization, respectively. However, the clinical outcome of AKI combined with ALI (AKI-ALI) remains unknown. The current study aimed to describe AKI-ALI's incidences, risk factors, and outcomes.

METHODS

The study population included patients aged 18-99 years with enough serum creatinine and liver testing hospitalized at 19 medical centers throughout China between 2000 and 2021. AKI was defined by Kidney Disease Improving Global Outcomes and ALI was defined by the change of liver enzymes based on Asia Pacific Association of Study of Liver consensus guidelines. Cox proportional hazard model was used to identify risk factors for AKI-ALI, and a time-dependent Cox proportional hazard regression model was used to estimate the association between AKI-ALI and in-hospital mortality.

RESULTS

Among the 18,461 patients with AKI, 1689 (9.1%) combined with ALI. Male patients or those who have used nonsteroidal anti-inflammatory drugs or vasopressors, and who have heart failure or shock, with higher AST or GGT values, were associated with an increased risk of AKI-ALI. Compared with AKI-nonALI, patients with AKI-ALI were at higher risk of in-hospitalized mortality (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1.54, 2.00). In addition, a stronger association between AKI-ALI and in-hospital mortality was found in those with lower AKI grades (p for interaction = 0.037).

CONCLUSIONS

ALI was not uncommon among patients with AKI, especially in patients who used vasopressors and had shock. This study highlights the association between AKI-ALI and a significantly increased risk of mortality. It suggests that dynamic monitoring of liver function is essential, particularly in patients with AST and GGT exceeding the normal upper limit, to improve the in-hospital prognosis of AKI patients.

Cardiorenal Syndrome Type 3 Review

The management of patients with complex comorbidity involving several organ systems can use an approach focused on each organ system independently or can use an approach trying to integrate various injuries and dysfunction into a single syndrome. Cardiorenal syndromes can develop with an initial injury to either the heart or kidney and then sequential involvement of the second organ. This can occur acutely or chronically. Cardiorenal syndrome type 3 is defined by acute renal injury with subsequent cardiac injury and/or dysfunction. Studies on these patients must use strict inclusion criteria. Pavan reported information on 100 patients with acute kidney injury in India to determine the frequency of cardiorenal syndrome type 3. He excluded patients with significant prior comorbidity. The most frequent causes of acute kidney injury in these patients were drug toxicity, gastroenteritis with volume contraction, and obstetrical complications. This study included 100 patients with acute kidney injury, and 29 developed cardiorenal syndrome type 3. Important outcomes included frequent mortality and chronic renal failure. Other studies have reported that cardiorenal syndrome type 3 occurs relatively infrequently. The analysis of large data bases has demonstrated that the development of acute kidney injury in hospitalized patients has important consequences, including the development of heart failure and increased mortality, but the complexity of these cohorts makes it difficult to determine the time course for the development of multisystem disorders. The pathogenesis of cardiorenal syndrome type 3 involves mitochondrial dysfunction, immune dysregulation, and ischemia-reperfusion. Cardiac events occur secondary to fluid overload, electrolyte disorders, and uremic toxins. These patients need increased attention during hospitalization and outpatient management in an effort to slow the progression of the primary disorder and treat complications.

The intellectual base and global trends in contrast-induced acute kidney injury: a bibliometric analysis

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired kidney injury. A comprehensive analysis of the current state of research in the field of CI-AKI will help to reveal trends and hot topics in the field. To date, there are no published bibliometric analyses related to CI-AKI studies. Here, we analyze the relevant literature since the emergence of the concept and provide valuable insights. The literature was collected from the Web of Science Core Collection. The data were analyzed visually using CiteSpace and VOSviewer software. We collected a total of 4775 papers, with the United States and Guangdong Acad Med Sci as the major publishing powers in terms of country/region and institution. J AM COLL CARDIOL was the journal with the most published and cocited articles. Cluster analysis showed that clinical trials are the current research hotspot. The areas of risk assessment, prevention strategies, risk factors, and vascular lesions have been popular in recent years. Research on the mechanism of injury in CI-AKI will be the focus of future research, which will be crucial to reduce the clinical incidence of CI-AKI. In summary, this study provides a comprehensive analysis of the development process in the field of CI-AKI and discusses future research directions based on the analysis of objective data from many studies on CI-AKI.

Development of a predictive nomogram for acute respiratory distress syndrome in patients with acute pancreatitis complicated with acute kidney injury

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a common complication in patients with acute pancreatitis (AP), especially when patients complicated with acute kidney injury (AKI), resulting in increased duration of hospitalization and mortality. It is of potential clinical significance to develop a predictive model to identify the the high-risk patients.

METHOD

AP patients complicated with AKI from January 2019 to March 2022 were enrolled in this study and randomly divided into training cohort and validation cohort at a ratio of 2:1. The Least absolute shrinkage and selection operator(LASSO) regression and machine learning algorithms were applied to select features. A nomogram was developed based on the multivariate logistic regression. The performance of the nomogram was evaluated by AUC, calibration curves, and decision curve analysis.

RESULTS

A total of 292 patients were enrolled in the study, with 206 in the training cohort and 86 in the validation cohort. Multivariate logistic analysis showed that IAP (Odds Ratio (OR)=4.60, 95%CI:1.23-18.24, p = 0.02), shock (OR = 12.99, 95%CI:3.47-64.04, p < 0.001), CRP(OR= 26.19, 95%CI:9.37-85.57, p < 0.001), LDH (OR = 13.13, 95%CI:4.76-40.42, p < 0.001) were independent predictors of ARDS. The nomogram was developed based on IAP, shock, CRP and LDH. The nomogram showed good discriminative ability with an AUC value of 0.954 and 0.995 in the training and validation cohort, respectively. The calibration curve indicating good concordance between the predicted and observed values. The DCA showed favorable net clinical benefit.

CONCLUSION

This study developed a simple model for predicting ARDS in AP patients complicated with AKI. The nomogram can help clinicians identify high-risk patients and optimize therapeutic strategies.

Effect of intraoperative low vs. conventional tidal volume on the incidence of postoperative acute kidney injury after noncardiac surgery: a two-center randomized clinical trial

BACKGROUND

In adults undergoing noncardiac surgery, the correlation between intraoperative tidal volume and postoperative acute kidney injury (AKI) is unclear. This study aimed to investigate the effects of low tidal volume ventilation on the incidence of postoperative AKI compared with conventional tidal volume in adults undergoing noncardiac surgery.

METHODS

This was a two-center prospective randomized controlled trial on adult patients who underwent noncardiac surgery and had a mechanical ventilation of >60 min. Patients were randomized to receive either a tidal volume of 6 mL/kg pre-predicted body weight (PBW, low tidal volume) or a tidal volume of 10 mL/kg pre-predicted body weight (conventional tidal volume). The primary outcome was the incidence of AKI after non-cardiac surgery. Appropriate statistical methods were used for this study.

RESULTS

Among the 1982 randomized patients, 943 with low tidal volume and 958 with conventional tidal volume were evaluable for the primary outcome. Postoperative AKI occurred in 12 patients (1.3%) in the low tidal volume group and 11 patients (1.1%) in the conventional tidal volume group, with an odds ratio of 0.889 (95%CI, 0.391-2.03) and a relative risk of 0.999 ([95%CI, 0.989-1.01]; P=0.804). Postoperative serum creatinine levels increased in 284 (30.0%) patients with low tidal volume compared to 316 (32.0%) patients with conventional tidal volume (P=0.251). No difference in postoperative serum creatinine levels was found between the two groups (57.5 [49.0-68.2] μmol/L vs. 58.8[50.4-69.5] μmol/L, P=0.056).

CONCLUSIONS

Among adults undergoing noncardiac surgery, low tidal volume mechanical ventilation did not significantly reduce the incidence of postoperative AKI compared with conventional tidal volume.

Reno- and hepato-protective effect of allopurinol after renal ischemia/reperfusion injury: Crosstalk between xanthine oxidase and peroxisome proliferator-activated receptor gamma signaling

Renal ischemia/reperfusion (I/R) is a common cause of acute kidney injury and remote liver damage is an ultimate negative outcome. Current treatments for renal I/R typically involve the use of antioxidants and anti-inflammatory to protect against oxidative stress and inflammation. Xanthine oxidase (XO) and PPAR-γ contribute to renal I/R-induced oxidative stress; however, the crosstalk between the two pathways remains unexplored. In the present study, we report that XO inhibitor, allopurinol (ALP), protects kidney and liver after renal I/R by PPAR-γ activation. Rats with renal I/R showed reduced kidney and liver functions, increased XO, and decreased PPAR-γ. ALP increased PPAR-γ expression and improved liver and kidney functions. ALP also reduced inflammation and nitrosative stress indicated by reduction in TNF-α, iNOS, nitric oxide (NO), and peroxynitrite formation. Interestingly, rats co-treated with PPAR-γ inhibitor, BADGE, and ALP showed diminished beneficial effect on renal and kidney functions, inflammation, and nitrosative stress. This data suggests that downregulation of PPAR-γ contributes to nitrosative stress and inflammation in renal I/R and the use of ALP reverses this effect by increasing PPAR-γ expression. In conclusion, this study highlights the potential therapeutic value of ALP and suggests targeting XO-PPAR-γ pathway as a promising strategy for preventing renal I/R injury.

The incidence of acute renal failure and high mortality rate in elderly patients hospitalized with community acquired pneumonia

Community acquired pneumonia is associated with high mortality and health care costs, especially in old age. The clinical presentation of pneumonia in the elderly may be asymptomatic or atypical. One of the known complication is an acute kidney injury. The purpose of our study was to estimate the incidence of this complication in elderly patients hospitalized with pneumonia in our geriatric hospital. From a group of 180 elderly patients hospitalized with community-acquired pneumonia 34.4 % developed acute kidney injury. In this group, 51.6 % of patients died compared to 14.4 % in the group of patients without acute kidney injury (p < 0.001). The lower level of e-GFR was significantly associated with mortality (p < 0.001): out of seven patients with e-GFR level of 15-29 mg/mmol, five patients died (71.4 %). Elderly patients with community-acquired pneumonia suffering acute kidney injury experienced worse in-hospital outcomes; mortality rate was significantly higher in our study. We found a relationship between low level of e-GFR and mortality. Clinicians should be alert for early detection and prevention of kidney injury in patients admitted with pneumonia.

Prazosin Protects the Liver Against Renal Ischemia/Reperfusion Injury in Rats

Acute kidney injury (AKI) is a common subsequent problem after many medical conditions. AKI is associated with distant organ dysfunction where systemic inflammation and oxidative stress play major roles. In this study, the effect of Prazosin, an α1-Adrenergic receptor antagonist, was investigated on the liver injury induced by kidney ischemia-reperfusion (I/R) in rats. Male adult Wistar rats (n=21) were divided into three groups: sham, kidney I/R, and kidney I/R pre-treated with Prazosin (1 mg/kg). Kidney I/R was induced by vascular clamping of the left kidney for 45 min to reduce the blood flow. Oxidative and antioxidant factors along with apoptotic (Bax, Bcl-2, caspase3), and inflammatory (NF-κβ, IL-1β, and IL-6) factors were measured in the liver at protein levels. Prazosin could reserve liver function (p<0.01) and increase glutathione level (p<0.05) after kidney I/R significantly. Malonil dialdehyde (MDA), a lipid peroxidation marker, was diminished more significantly in Prazosin-treated rats compared to the kidney I/R group (p<0.001). Inflammatory and apoptotic factors were diminished by Prazosin pre-treatment in the liver tissue (p<0.05). Pre-administration of Prazosin could preserve liver function and decrease its inflammatory and apoptotic factors under kidney I/R conditions.

A human kidney and liver organoid-based multi-organ-on-a-chip model to study the therapeutic effects and biodistribution of mesenchymal stromal cell-derived extracellular vesicles

Mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) show therapeutic potential in multiple disease models, including kidney injury. Clinical translation of sEVs requires further preclinical and regulatory developments, including elucidation of the biodistribution and mode of action (MoA). Biodistribution can be determined using labelled sEVs in animal models which come with ethical concerns, are time-consuming and expensive, and may not well represent human physiology. We hypothesised that, based on developments in microfluidics and human organoid technology, in vitro multi-organ-on-a-chip (MOC) models allow us to study effects of sEVs in modelled human organs like kidney and liver in a semi-systemic manner. Human kidney- and liver organoids combined by microfluidic channels maintained physiological functions, and a kidney injury model was established using hydrogenperoxide. MSC-sEVs were isolated, and their size, density and potential contamination were analysed. These sEVs stimulated recovery of the renal epithelium after injury. Microscopic analysis shows increased accumulation of PKH67-labelled sEVs not only in injured kidney cells, but also in the unharmed liver organoids, compared to healthy control conditions. In conclusion, this new MOC model recapitulates therapeutic efficacy and biodistribution of MSC-sEVs as observed in animal models. Its human background allows for in-depth analysis of the MoA and identification of potential side effects.

Advances in laboratory detection of acute kidney injury

Recent advances have improved our understanding of the epidemiology and pathophysiology of acute kidney injury (AKI). So far, the Kidney Disease: Improving Global Outcome guidelines define and stratify kidney injury based on increases in serum creatinine level and/or decreases in urine output. Although the term AKI acknowledges the existence of cellular injury, its diagnosis is still only defined by the reduced excretory function of the kidney. New biomarkers that aid a better understanding of the relationship between acute tubular injury and kidney dysfunction have been identified, reflecting the advances in molecular biology. The expression of some of these novel biomarkers precedes changes in conventional biomarkers or can increase their predictive power. Therefore, they might enhance the clinical accuracy of the definition of AKI. This review summarizes the limitations of the current AKI classification and a panel of candidate biomarkers for augmenting AKI classification and recognition of AKI subphenotypes. We expect that the integration of appropriately selected biomarkers in routine clinical practice can improve AKI care.

Multi-Omics Techniques Make it Possible to Analyze Sepsis-Associated Acute Kidney Injury Comprehensively

Sepsis-associated acute kidney injury (SA-AKI) is a common complication in critically ill patients with high morbidity and mortality. SA-AKI varies considerably in disease presentation, progression, and response to treatment, highlighting the heterogeneity of the underlying biological mechanisms. In this review, we briefly describe the pathophysiology of SA-AKI, biomarkers, reference databases, and available omics techniques. Advances in omics technology allow for comprehensive analysis of SA-AKI, and the integration of multiple omics provides an opportunity to understand the information flow behind the disease. These approaches will drive a shift in current paradigms for the prevention, diagnosis, and staging and provide the renal community with significant advances in precision medicine in SA-AKI analysis.

Interplay between mineral bone disorder and cardiac damage in acute kidney injury: from Ca2+ mishandling and preventive role of Klotho in mice to its potential mortality prediction in human

Biomarkers of mineral bone disorders (MBD) including phosphorus, fibroblast growth factor (FGF)-23 and Klotho are strongly altered in patients with acute kidney injury (AKI) who have high cardiac outcomes and mortality rates. However, the crosslink between MBD and cardiac damage after an AKI episode still remains unclear. We tested MBD and cardiac biomarkers in an experimental AKI model after 24 or 72 hours of folic acid injection and we analyzed structural cardiac remodeling, intracellular calcium (Ca²⁺) dynamics in cardiomyocytes and cardiac rhythm. AKI mice presented high levels of FGF-23, phosphorus and cardiac troponin T and exhibited a cardiac hypertrophy phenotype accompanied by an increase in systolic Ca²⁺ release 24 hours after AKI. Ca²⁺ transients and contractile dysfunction were reduced 72 hours after AKI while diastolic sarcoplasmic reticulum Ca²⁺ leak, pro-arrhythmogenic Ca²⁺ events and ventricular arrhythmias were increased. These cardiac events were linked to the activation of the calcium/calmodulin-dependent kinase II pathway through the increased phosphorylation of ryanodine receptors and phospholamban specific sites after AKI. Cardiac hypertrophy and the altered intracellular Ca²⁺ dynamics were prevented in transgenic mice overexpressing Klotho after AKI induction. In a translational retrospective longitudinal clinical study, we determined that combining FGF-23 and phosphorus with cardiac troponin T levels achieved a better prediction of mortality in AKI patients at hospital admission. Thus, monitoring MBD and cardiac damage biomarkers could be crucial to prevent mortality in AKI patients. In this setting, Klotho might be considered as a new cardioprotective therapeutic tool to prevent deleterious cardiac events in AKI conditions.

Accuracy of diagnosing acute kidney injury by assessing urine output within the first week of life in extremely preterm infants

BACKGROUND

Neonatal acute kidney injury (AKI) is associated with increased mortality and is often assessed with the neonatal modified Kidney Disease: improving Global Outcomes (KDIGO) classification, which uses changes in serum creatinine levels. However, because this classification has many drawbacks, a novel method, the neonatal Risk, Injury, Failure, Loss, and End-Stage Kidney Disease (nRIFLE) classification for diagnosing neonatal AKI according to urine output (UO), was recently proposed. To date, no data on the incidence of AKI according to nRIFLE are available for extremely preterm infants (born at gestational age less than 28 weeks). This study was conducted to clarify the association between incidence of AKI and in-hospital mortality in extremely preterm infants.

METHODS

Of 171 extremely preterm infants hospitalized from 2006 to 2020, 84 in whom indwelling bladder catheters were placed for UO measurements within 24 h of life were included. The incidence of AKI was assessed using the nRIFLE classification. In-hospital mortality was compared between patients with AKI and those without it.

RESULTS

The incidence of AKI during the first week of life was 56% and that of in-hospital mortality was significantly higher in patients with AKI (25.5%) than in those without it (2.8%). The odds ratio was 12.3 with 95% confidence interval ranging from 1.5 to 100.0.

CONCLUSION

The incidence of AKI according to nRIFLE was higher than reported in most previous studies using the neonatal modified KDIGO classification, suggesting that assessment by nRIFLE criteria using UO may improve diagnostic accuracy of AKI in extremely preterm infants.

Association of FIB-4 index and clinical outcomes in critically ill patients with acute kidney injury: a cohort study

Background

The relationship between fibrosis-4 (FIB-4) index and clinical outcomes in patients with acute kidney injury (AKI) is unclear. We aimed to investigate the association between FIB-4 index and all-cause mortality in critically ill patients with AKI.

Methods

We used data from the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC-III) database (v1.4). The FIB-4 score was calculated using the existing formulas. logistic regression model, and Cox proportional hazards model were used to assessed the relationship between the FIB-4 index and in-hospital,28-day and 90-day mortality, respectively.

Results

A total of 3592 patients with AKI included in the data analysis. 395 (10.99%) patients died during hospitalization and 458 (12.74%) patients died in 28-day. During the 90-day follow-up, 893 (22.54%) patients were dead. An elevated FIB-4 value was significantly associated with increased in-hospital mortality when used as a continuous variable (odds ratio [OR] 1.183, 95% confidence interval [CI] 1.072–1.305, P = 0.002) and as a quartile variable (OR of Q2 to Q4 1.216–1.744, with Q1 as reference). FIB-4 was positively associated with 28-day mortality of AKI patients with hazard ratio (HR) of 1.097 (95% CI 1.008, 1.194) and 1.098 (95% 1.032, 1.167) for 90-day mortality, respectively.

Conclusion

This study demonstrated the FIB-4 index is associated with clinical outcomes in critically ill patients with acute kidney injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02071-2.

Incidence- and In-hospital Mortality-Related Risk Factors of Acute Kidney Injury Requiring Continuous Renal Replacement Therapy in Patients Undergoing Surgery for Acute Type a Aortic Dissection

Background: Few studies on the risk factors for postoperative continuous renal replacement therapy (CRRT) in a homogeneous population of patients with acute type A aortic dissection (AAAD). This retrospective analysis aimed to investigate the risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery and to discuss the perioperative comorbidities and short-term outcomes. Methods: The study collected electronic medical records and laboratory data from 432 patients undergoing surgery for AAAD between March 2009 and June 2021. All the patients were divided into CRRT and non-CRRT groups; those in the CRRT group were divided into the survivor and non-survivor groups. The univariable and multivariable analyses were used to identify the independent risk factors for CRRT and in-hospital mortality. Results: The proportion of requiring CRRT and in-hospital mortality in the patients with CRRT was 14.6 and 46.0%, respectively. Baseline serum creatinine (SCr) [odds ratio (OR), 1.006], cystatin C (OR, 1.438), lung infection (OR, 2.292), second thoracotomy (OR, 5.185), diabetes mellitus (OR, 6.868), AKI stage 2-3 (OR, 22.901) were the independent risk factors for receiving CRRT. In-hospital mortality in the CRRT group (46%) was 4.6 times higher than in the non-CRRT group (10%). In the non-survivor (n = 29) and survivor (n = 34) groups, New York Heart Association (NYHA) class III-IV (OR, 10.272, P = 0.019), lactic acidosis (OR, 10.224, P = 0.019) were the independent risk factors for in-hospital mortality in patients receiving CRRT. Conclusion: There was a high rate of CRRT requirement and high in-hospital mortality after AAAD surgery. The risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery were determined to help identify the high-risk patients and make appropriate clinical decisions. Further randomized controlled studies are urgently needed to establish the risk factors for CRRT and in-hospital mortality.

Evaluation of the systemic alterations triggers by Porthidium lansbergii lansbergii snake venom

The systemic effects generated by Porthidium lansbergii lansbergii envenoming, a species found in the northern region of Colombia, is poorly known. The present study aimed to analyze for the first time the mice's behavior, the histological alterations, and changes in biochemical markers levels resulting from the intraperitoneal injection of an LD₅₀ of P. lansbergii lansbergii snake venom on mice. The envenoming mice displayed hypodynamic condition, clonic head movements, accompanied by bradypnea and thoracoabdominal imbalance. After 7 h of envenoming, the mice showed an ecchymotic region at the injection site, including bleeding in the pleural, liver, and kidney capsules. The effect on the brain revealed a micro-hemorrhage in the sensorimotor cortex with substantial loss of neurons. The venom caused dilated blood vessels in lung tissue, with endothelial necrosis associated with alveolar rupture. The liver showed parenchyma alteration with many extravasated erythrocytes. The kidneys exhibited renal tubules necrosis and a statistically significant increase in creatinine concentration. ALP and ALT's enzymatic activities remained constant at 7 h after envenoming but increased at 12 h. AST and LDH were significantly increased at 7 h but decreased to the near baseline 12 h after venom administration. Massive hemorrhages could trigger a hypovolemic shock, which could lead to death after several h without treatment. Knowledge of P. lansbergii lansbergii snake bites' injuries is essential to make the appropriate diagnostic in human envenoming cases by this snake.

Brain to periphery in acute ischemic stroke: Mechanisms and clinical significance

The social and public health burdens of ischemic stroke have been increasing worldwide. In addition to focal brain damage, acute ischemic stroke (AIS) provokes systemic abnormalities across peripheral organs. AIS profoundly alters the autonomic nervous system, hypothalamic-pituitary-adrenal axis, and immune system, which further yield deleterious organ-specific consequences. Poststroke systemic pathological alterations in turn considerably contribute to the progression of ischemic brain injury, which accounts for the substantial impact of systemic complications on stroke outcomes. This review provides a comprehensive and updated pathophysiological model elucidating the systemic effects of AIS. To address their clinical significance and inform stroke management, we also outline the resulting systemic complications at particular stages of AIS and highlight the mechanisms. Future therapeutic strategies should attempt to integrate the treatment of primary brain lesions with interventions for secondary systemic complications, and should be tailored to patient individualized characteristics to optimize stroke outcomes.

Curcumin plays a protective role against septic acute kidney injury by regulating the TLR9 signaling pathway

Background

This study aims to evaluate the inhibitory effect of curcumin (Cur) on the progression of septic acute kidney injury (SAKI), in order to improve the survival rate in this patient population.

Methods

Acute kidney injury (AKI) was induced by cecal ligation perforation (CLP) in Sprague-Dawley (SD) rats. Using this AKI animal model, the survival rate of the rats was evaluated at different time points after Cur treatment to explore whether Cur can improve survival in an animal model of AKI. The expression levels of inflammatory factors (NF-κB, TNF-α, and IL-10), organ injury markers [urea nitrogen (UN), creatinine (Cr), alanine aminotransferase (ALT), aspartate aminotransferase (AST), amylase, creatine kinase (CK), and lactate dehydrogenase (LDH)], and disease progression markers [neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and cystatin-C (CysC)] were determined using an enzyme-linked immunosorbent assay (ELISA).

Results

The serum levels of UN, Cr, NF-κB, ALT, AST, amylase, CK, LDH, inflammatory factors TNF-α and IL-10, and markers of early diagnosis of SAKI (NGAL, CysC, KIM-1) were significantly lower in the curcumin group than those in the placebo group (P<0.05). In addition, serum levels of TLR9 and its downstream molecules MyD88, IRF5, and IRF7 in the curcumin group were significantly lower than those in the placebo group (P<0.05). The application of TLR9-specific inhibitors to experimental rats led to similar results as those obtained in the curcumin group, whose detection indexes were significantly lower than those in the placebo treatment group (P<0.05).

Conclusions

Given the excellent performance of Cur in anti-tumor, anti-oxidation, anti-inflammatory, and other clinical trials, it is very likely to be further developed as a potential drug for the clinical treatment of AKI.

Impact of acute kidney injury on in-hospital outcomes in Chinese patients with community acquired pneumonia

BACKGROUND

Acute kidney injury (AKI) is a frequent complication of community acquired pneumonia (CAP). However, the impact of AKI on in-hospital outcomes of patients with CAP in the Chinese population remains unclear.

METHODS

Patients diagnosed with CAP were evaluated in this retrospective observational study. Multiple Cox regression models were employed to identify the association between AKI and in-hospital mortality and 30-day mortality, respectively.

RESULTS

A total of 4213 patients were recruited; 950 (22.5%) patients were diagnosed with AKI. Independent risk factors for AKI were age, male gender, hypertension, cardiac dysfunction, diabetes, chronic kidney disease, acute respiratory failure, use of diuretics, use of vasoactive drugs, and CURB-65. Cox proportional hazards regression revealed AKI, use of angiotensin receptor blocker, hypertension, CURB-65, acute respiratory failure, and use of vasoactive drugs to be independent risk factors for both in-hospital and 30-day mortality. Compared to patients without AKI, those suffering AKI were found to have 1.31-fold (HR 1.31, 95% CI, 1.04-1.66; P = 0.023) and 1.29-fold (HR 1.29, 95% CI, 1.02-1.62; P = 0.033) increased in-hospital and 30-day mortality risks, respectively. In addition, patients with AKI were likely to require admission to intensive care unit (ICU) (42.9% versus 11.4%; P < 0.001), mechanical ventilation (33.8% versus 9.3%; P < 0.001), invasive mechanical ventilation (25.9% versus 5.8%; P < 0.001), non-invasive mechanical ventilation (25.4% versus 7.1%; P < 0.001), and experienced a longer duration of hospital stay (14 days versus 10 days; P < 0.001) than those without AKI. However, no significant difference in ICU stay (11 days versus 10 days; P = 0.099) and duration of mechanical ventilation (8 days versus 8 days; P = 0.369) between AKI and non-AKI groups was found.

CONCLUSION

AKI was common in Chinese patients with CAP. Patients with CAP who developed AKI had worse in-hospital outcomes.

Grb2 Induces Cardiorenal Syndrome Type 3: Roles of IL-6, Cardiomyocyte Bioenergetics, and Akt/mTOR Pathway

Cardiorenal syndrome type 3 (CRS-3) is damage to the heart following acute kidney injury (AKI). Although many experiments have found that inflammation, oxidative stress, and cardiomyocyte death are involved in cardiomyocyte pathophysiological alterations during CRS-3, they lack a non-bias analysis to figure out the primary mediator of cardiac dysfunction. Herein proteomic analysis was operated in CRS-3 and growth factor receptor-bound protein 2 (Grb2) was identified as a regulator involving AKI-related myocardial damage. Increased Grb2 was associated with cardiac diastolic dysfunction and mitochondrial bioenergetics impairment; these pathological changes could be reversed through the administration of a Grb2-specific inhibitor during AKI. Molecular investigation illustrated that augmented Grb2 promoted cardiomyocyte mitochondrial metabolism disorder through inhibiting the Akt/mTOR signaling pathway. Besides that, Mouse Inflammation Array Q1 further identified IL-6 as the upstream stimulator of Grb2 upregulation after AKI. Exogenous administration of IL-6 induced cardiomyocyte damage and mitochondrial bioenergetics impairment, whereas these effects were nullified in cardiomyocytes pretreated with Grb2 inhibitor. Our results altogether identify CRS-3 to be caused by the upregulations of IL-6/Grb2 which contribute to cardiac dysfunction through inhibiting the Akt/mTOR signaling pathway and inducing cardiomyocyte mitochondrial bioenergetics impairment. This finding provides a potential target for the clinical treatment of patients with CRS-3.

Melatonin Attenuates ox-LDL-Induced Endothelial Dysfunction by Reducing ER Stress and Inhibiting JNK/Mff Signaling

Endothelial dysfunction, which is characterized by damage to the endoplasmic reticulum (ER) and mitochondria, is involved in a variety of cardiovascular disorders. Here, we explored whether mitochondrial damage and ER stress are associated with endothelial dysfunction. We also examined whether and how melatonin protects against oxidized low-density lipoprotein- (ox-LDL-) induced damage in endothelial cells. We found that CHOP, GRP78, and PERK expressions, which are indicative of ER stress, increased significantly in response to ox-LDL treatment. ox-LDL also induced mitochondrial dysfunction as evidenced by decreased mitochondrial membrane potential, increased mitochondrial ROS levels, and downregulation of mitochondrial protective factors. In addition, ox-LDL inhibited antioxidative processes, as evidenced by decreased antioxidative enzyme activity and reduced Nrf2/HO-1 expression. Melatonin clearly reduced ER stress and promoted mitochondrial function and antioxidative processes in the presence of ox-LDL. Molecular investigation revealed that ox-LDL activated the JNK/Mff signaling pathway, and melatonin blocked this effect. These results demonstrate that ox-LDL induces ER stress and mitochondrial dysfunction and activates the JNK/Mff signaling pathway, thereby contributing to endothelial dysfunction. Moreover, melatonin inhibited JNK/Mff signaling and sustained ER homeostasis and mitochondrial function, thereby protecting endothelial cells against ox-LDL-induced damage.

Epigenetic Regulation of the N-Terminal Truncated Isoform of Matrix Metalloproteinase-2 (NTT-MMP-2) and Its Presence in Renal and Cardiac Diseases

Several clinical and experimental studies have documented a compelling and critical role for the full-length matrix metalloproteinase-2 (FL-MMP-2) in ischemic renal injury, progressive renal fibrosis, and diabetic nephropathy. A novel N-terminal truncated isoform of MMP-2 (NTT-MMP-2) was recently discovered, which is induced by hypoxia and oxidative stress by the activation of a latent promoter located in the first intron of the MMP2 gene. This NTT-MMP-2 isoform is enzymatically active but remains intracellular in or near the mitochondria. In this perspective article, we first present the findings about the discovery of the NTT-MMP-2 isoform, and its functional and structural differences as compared with the FL-MMP-2 isoform. Based on publicly available epigenomics data from the Encyclopedia of DNA Elements (ENCODE) project, we provide insights into the epigenetic regulation of the latent promoter located in the first intron of the MMP2 gene, which support the activation of the NTT-MMP-2 isoform. We then focus on its functional assessment by covering the alterations found in the kidney of transgenic mice expressing the NTT-MMP-2 isoform. Next, we highlight recent findings regarding the presence of the NTT-MMP-2 isoform in renal dysfunction, in kidney and cardiac diseases, including damage observed in aging, acute ischemia-reperfusion injury (IRI), chronic kidney disease, diabetic nephropathy, and human renal transplants with delayed graft function. Finally, we briefly discuss how our insights may guide further experimental and clinical studies that are needed to elucidate the underlying mechanisms and the role of the NTT-MMP-2 isoform in renal dysfunction, which may help to establish it as a potential therapeutic target in kidney diseases.

Acute kidney injury may impede results after transcatheter aortic valve implantation

INTRODUCTION

Severe complications after transcatheter aortic valve implantation (TAVI) are rare due to increasing procedural safety. However, TAVI procedure-related haemodynamic instability and increased risk of infection may affect renal functional reserve with subsequent renal acidosis and hyperkalaemia.

OBJECTIVE

In this study, we investigated incidence, modifiable risk factors and prognosis of acute kidney injury (AKI) and AKI complicated by hyperkalaemia, pulmonary oedema or metabolic acidosis after TAVI.

METHODS

In a retrospective single-centre study, 804 consecutive patients hospitalized during 2017 and 2018 for elective TAVI were included. AKI was defined according to the 'Kidney Disease Improving Global Outcome' (KDIGO) initiative. Variables on co-morbidities, intra-/post-interventional complications and course of renal function up to 6 months after index-hospitalization were assessed. In multivariate regression analyses, risk factors for the development of AKI, complicated AKI, renal non-recovery from AKI and in-hospital mortality were determined.

RESULTS

Incidence of AKI was 13.8% (111/804); in-hospital mortality after TAVI was 2.3%. AKI was an independent risk factor for in-hospital mortality, odds ratio (OR) 10.3 (3.4-31.6), P < 0.001, further increasing to OR = 21.8 (6.6-71.5), P < 0.001 in patients with AKI complicated by hyperkalaemia, pulmonary oedema or metabolic acidosis, n = 57/111 (51.4%). Potentially modifiable, interventional factors independently associated with complicated AKI were infection [OR = 3.20 (1.61-6.33), P = 0.001] and red blood cell transfusion [OR = 5.04 (2.67-9.52), P < 0.001]. Valve type and size, contrast volume and other intra-interventional characteristics, such as the need for tachycardial pacing, did not influence the development of AKI. Eleven of 111 (9.9%) patients did not recover from AKI, mostly affecting patients with cardiac decompensation. In 18/111 (16.2%) patients, information concerning AKI was provided in discharge letter. Within 6 months after TAVI, higher proportion of patients with AKI showed progression of pre-existing chronic kidney disease compared with patients without AKI [14/29, 48.3% versus 54/187, 28.9%, OR = 2.3 (95% confidence interval 1.0-5.1), P = 0.036].

CONCLUSIONS

AKI is common and may impede patient outcome after TAVI with acute complications such as hyperkalaemia or metabolic acidosis and adverse renal function until 6 months after intervention. Our study findings may contribute to refinement of allocation of appropriate level of care in and out of hospital after TAVI.

Dexmedetomidine ameliorates renal ischemia reperfusion-mediated activation of the NLRP3 inflammasome in alveolar macrophages

Renal ischemia-reperfusion (rI/R) is a risk factor for acute lung injury (ALI). Alveolar macrophages (AMs) activation mediated by rI/R-induced ALI is one of the pathogeneses associated with the development of ALI. In rI/R, α₂-adrenergic receptor agonists have been indicated to be effective in decreasing urea nitrogen concentrations. In this study, we explored the underlying pathogenesis of the clinically obtainable α₂-adrenergic receptor agonist dexmedetomidine (DEX) in protecting against rI/R -mediated AMs activation. We incubated AMs with the serum of sham and rI/R rats in the presence or absence of various concentrations of DEX. We used an enzyme-linked immunosorbent assay to detect the secretion levels of GSH, LDH, IL-18, IL-1β, and HMGB1 in the culture supernatant. We employed real-time polymerase chain reaction to assess the expression of NOX-4 mRNA, and western blotting to observe the protein levels of NOX-4, the NLRP3 inflammasome, AMPK, and eNOS. In addition, we used immunofluorescence to analyze ROS and MMP activity. Incubation of AMs with DEX suppressed rI/R-mediated cellular LDH production and ROS release. DEX also abolished the rI/R-mediated decrease in the activity of GSH and increased the levels of the rI/R-related NADPH oxidase protein NOX-4. Furthermore, DEX reduced the amelioration of the mitochondrial potential induced by rI/R. Our study showed that DEX inhibits rI/R-mediated levels of the NLRP3 inflammasome proteins ASC, NLRP3, HMGB1 and p20, and ameliorates rI/R-mediated AMPK signaling inactivation. Therefore, DEX reduces the levels of two mediators that are activated by the NLRP3 inflammasome: IL-18 and IL-1β. Finally, our study established that DEX mitigates the rI/R-mediated decrease in eNOS, demonstrating its protective functions against AMs activation. In conclusion, our study demonstrated that the protective action of DEX in AMs is induced through amelioration of HMGB1-NLRP3 inflammasome-AMPK signaling. Our results suggest that the anesthetic reagent DEX exerts beneficial effects to ameliorate rI/R-induced ALI.

Kidney Ischemia-Reperfusion Elicits Acute Liver Injury and Inflammatory Response

Ischemia-reperfusion (IR) is a common risk factor that causes acute kidney injury (AKI). AKI is associated with dysfunction of other organs also known as distant organ injury. The liver function is often compromised in patients with AKI and in animal models. However, the underlying mechanisms are not fully understood. Inflammatory response plays an important role in IR-induced tissue injury. Although increased proinflammatory cytokines have been detected in the kidney and the distant organs after renal IR, their original sources remain uncertain. In the present study, we investigated the acute effect of renal IR on hepatic inflammatory cytokine expression and the mechanism involved. Sprague-Dawley rats that were subjected to renal IR (ischemia for 45 min followed by reperfusion for 1 h or 6 h) had increased plasma levels of creatinine, urea, and transaminases, indicating kidney and liver injuries. There was a significant increase in the expression of proinflammatory cytokine mRNA (MCP-1, TNF-α, IL-6) in the kidney and liver in rats with renal IR. This was accompanied by a significant increase in proinflammatory cytokine protein levels in the plasma, kidney, and liver. Activation of a nuclear transcription factor kappa B (NF-κB) was detected in the liver after renal IR. The inflammatory foci and an increased myeloperoxidase (MPO) activity were detected in the liver after renal IR, indicating hepatic inflammatory response and leukocyte infiltration. These results suggest that renal IR can directly activate NF-κB and induce acute production of proinflammatory cytokines in the liver. Renal IR-induced hepatic inflammatory response may contribute to impaired liver function and systemic inflammation.