The aftermath of acute kidney injury: a narrative review of long-term mortality and renal function

Differences in mortality and risk factors, two years after endovascular repair of ruptured abdominal aortic aneurysms - Reassessment analysis

OBJECTIVE

The prevalence of abdominal aortic aneurysms (AAA) increases with age. Elective intervention for AAA is critical to prevent rupture associated with very high mortality among older males.

METHODS

The aim of this study was to address the impact of post-contrast acute kidney-PC-AKI injury among patients treated with endovascular repair of ruptured AAA-EVAR on outcomes such as new onset chronic kidney disease-CKD and mortality among patients within a two-year trial.

RESULTS

The same study group (of n = 192 patients) underwent reassessment, two years after EVAR treatment. The overall mortality rate was 16.67%, and it was higher in the AKI group - 38.89%. CKD patients had a mortality rate of 23.88% (n = 16). Among patients with an aneurysm diameter >67 mm mortality rate reached 20% (n = 6), while in the previously reported diabetes mellitus group 37.93% (n = 11). New onset of CKD was diagnosed in 23% of cases. Preexisting CKD patients with PC- AKI contributed to a 33.33% mortality rate (n = 8).

CONCLUSION

This study concludes that PC-AKI impacts outcomes and survival in endovascularly treated AAAs. Type 2 diabetes and preexisting chronic kidney disease are associated with higher mortality within a 2-year follow-up, however gender factor was not significant. A larger aneurysm diameter is related with a higher prevalence of PC-AKI. These factors should be taken into account during screening, qualifying patients for the treatment and treating patients with AAA. It may help to identify high-risk individuals and tailor preventive measurements and treatment options accordingly, improving treatment results and reducing mortality.

The Impact of Acute Kidney Injury on Chronic Kidney Disease After Cardiac Surgery: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the impact of acute kidney injury on transition to chronic kidney disease (CKD) after cardiac surgery and to determine frequency of incident CKD in these patients.

DESIGN

A systematic review and meta-analysis of observational studies.

SETTING

Electronic databases Medline and Embase were systematically searched from 1974 to February 6, 2023.

PARTICIPANTS

Eligible studies were original observational studies on adult cardiac surgery patients, written in the English language, and with clear kidney disease definitions. Exclusion criteria were studies with previously transplanted populations, populations with preoperative kidney impairment, ventricular assist device procedures, endovascular procedures, a kidney follow-up period of <90 days, and studies not presenting necessary data for effect size calculations.

INTERVENTIONS

Patients developing postoperative acute kidney injury after cardiac surgery were compared with patients who did not develop acute kidney injury.

MEASUREMENTS AND MAIN RESULTS

The search identified 4,329 unique studies, 87 underwent full-text review, and 12 were included for analysis. Mean acute kidney injury occurrence across studies was 16% (minimum-maximum: 8-50), while mean occurrence of CKD was 24% (minimum-maximum: 3-35), with high variability depending on definitions and follow-up time. Acute kidney injury was associated with increased odds of CKD in all individual studies. The pooled odds ratio across studies was 5.67 (95% confidence interval, 3.34-9.64; p < 0.0001).

CONCLUSIONS

Acute kidney injury after cardiac surgery was associated with a more than 5-fold increased odds of developing CKD. New-onset CKD occurred in almost 1 in 4 patients in the years after surgery.

Aurantiamide mitigates acute kidney injury by suppressing renal necroptosis and inflammation via GRPR-dependent mechanism

Acute kidney injury (AKI) manifests as a clinical syndrome characterised by the rapid accumulation of metabolic wastes, such as blood creatinine and urea nitrogen, leading to a sudden decline in renal function. Currently, there is a lack of specific therapeutic drugs for AKI. Previously, we identified gastrin-releasing peptide receptor (GRPR) as a pathogenic factor in AKI. In this study, we investigated the therapeutic potential of a novel Chinese medicine monomer, aurantiamide (AA), which exhibits structural similarities to our previously reported GRPR antagonist, RH-1402. We compared the therapeutic efficacy of AA with RH-1402 both in vitro and in vivo using various AKI models. Our results demonstrated that, in vitro, AA attenuated injury, necroptosis, and inflammatory responses in human renal tubular epithelial cells subjected to repeated hypoxia/reoxygenation and lipopolysaccharide stimulation. In vivo, AA ameliorated renal tubular injury and inflammation in mouse models of ischemia/reperfusion and cecum ligation puncture-induced AKI, surpassing the efficacy of RH-1402. Furthermore, molecular docking and cellular thermal shift assay confirmed GRPR as a direct target of AA, which was further validated in primary cells. Notably, in GRPR-silenced HK-2 cells and GRPR systemic knockout mice, AA failed to mitigate renal inflammation and injury, underscoring the importance of GRPR in AA's mechanism of action. In conclusion, our study has demonstrated that AA serve as a novel antagonist of GRPR and a promising clinical candidate for AKI treatment.

Pediatric acute kidney injury and adverse health outcomes: using a foundational framework to evaluate a causal link

Acute kidney injury (AKI) is a major global health problem, expensive to manage, and its associations with negative pediatric health outcomes have been clearly demonstrated. One of the most fundamental questions to consider as we use previous epidemiological information to advance research and care paradigms is the strength of the causal link between pediatric AKI and health outcomes. In this review, we apply the foundational framework of the Bradford Hill criteria to evaluate the extent to which a causal link exists between AKI and the associated adverse outcomes in children. Available data in children support a causal link between AKI and short-term outcomes including mortality, length of stay, and ventilation time. Clarifying the causal nature of longer term associations requires further high-quality observational studies in children, careful consideration of what defines the most meaningful and measurable longer term outcomes after pediatric AKI, and integration of evolving biological data related to mechanisms of disease. Preventing or mitigating AKI should lead to improved outcomes. Demonstrating such reversibility will solidify confidence in the causal relationship, improve child health, and highlight an aspect which is highly relevant to clinicians, scientists, and policy makers.

Bibliometric and visual analysis of immunisation associated with acute kidney injury from 2003 to 2023

Objective

This study aims to conduct a detailed bibliometric and visual analysis of acute kidney injury (AKI) and immune-related research conducted over the past two decades, focusing on identifying emerging trends and key areas of interest.

Methods

The Web of Science Core Collection (WoSCC) was utilised for the meticulous examination of various parameters including publication volume, authorship, geographic distribution, institutional contributions, journal sources, prevalent keywords and citation frequencies. Data were intricately visualised and interpreted using VOSviewer, CiteSpace and Excel 365 software.

Results

Analysis of the WoSCC database revealed 3,537 articles on AKI and immunisation, originating from 94 countries and regions, involving 3,552 institutions and authored by 18,243 individuals. Notably, the top five countries contributing to this field were the United States, China, Germany, Italy and the United Kingdom, with the United States leading with 35.76% of total publications. Among the 3,552 contributing institutions, those in the United States were predominant, with Harvard University leading with 134 papers and 3,906 citations. Key journals driving productivity included Frontiers in Immunology, Kidney International, Journal of the American Society of Nephrology and International Journal of Molecular Sciences, with Kidney International being the most cited, followed by Journal of the American Society of Nephrology and New England Journal of Medicine. Prominent authors in the field included Ronco Claudio, Okusa Mark D and Anders, Hans-Joachim. Co-citation clustering and timeline analysis highlighted recent research foci such as COVID-19, immune checkpoint inhibitors, regulated necrosis, cirrhosis and AKI. Keyword analysis identified "inflammation," "ischaemia-reperfusion injury," "sepsis," "covid-19," and "oxidative stress" as prevalent terms.

Conclusion

This study provides the first bibliometric analysis of AKI and immune research, offering a comprehensive overview of research hotspots and evolving trends within the field.

Does cardiac impairment develop in ischemic renal surgery in rats depending on the reperfusion time?

Background

Renal dysfunction is known to cause heart failure. However, renal dysfunction associated with kidney surgeries (mediated by reperfusion injury) that affects the cardiac physiological function, especially during the recovery and repair phase of renal surgery is unknown.

Method

Male Wistar rats (238 ± 18 g) were subjected to renal sham and ischemia-reperfusion (IR-bilateral clamping for 15 min/45 min and reperfusion for 24 h/48 h/7 days) surgeries. At the end of the experiment, the heart was isolated from the animal (to exclude neurohormonal influence) and perfused for 60 min with Krebs-Hanseleit buffer to study the physiological changes.

Result

Renal artery bilateral occlusion for 45 min that creates ischemia, followed by 24 h of reperfusion did not impart any significant cardiac physiological functional decline but 48 h of reperfusion exhibited a significant decline in cardiac hemodynamic indices (Rate pressure product in x104 mmHg*beats/min: Sham- 3.53 ± 0.19, I45_R48-2.82 ± 0.21) with mild tissue injury. However, 7 days of reperfusion inflict significant physiological decline (Rate pressure product in x104 mmHg*beats/min - 2.5 ± 0.14) and tissue injury (Injury score- 4 ± 1.5) in isolated rat hearts. Interestingly, when the renal artery bilateral occlusion time was reduced to 15 min the changes in the hearts were negligible after 7 days. Cellular level exploration reveals a positive relation between functional deterioration of mitochondria and elevated mitochondrial oxidative stress and inflammation with cardiac physiological decline and injury linked with renal ischemia-reperfusion surgery.

Conclusion

Cardiac functional decline associated with renal surgery is manifested during renal repair or recovery. This decline depends on cardiac mitochondrial health, which is negatively influenced by the renal IR mediators and kidney function.

LXA4 protected mice from renal ischemia/reperfusion injury by promoting IRG1/Nrf2 and IRAK-M-TRAF6 signal pathways

Excessive inflammatory response and increased oxidative stress play an essential role in the pathophysiology of ischemia/reperfusion (I/R)-induced acute kidney injury (IRI-AKI). Emerging evidence suggests that lipoxin A4 (LXA4), as an endogenous negative regulator in inflammation, can ameliorate several I/R injuries. However, the mechanisms and effects of LXA4 on IRI-AKI remain unknown. In this study, A bilateral renal I/R mouse model was used to evaluate the role of LXA4 in wild-type, IRG1 knockout, and IRAK-M knockout mice. Our results showed that LXA4, as well as 5-LOX and ALXR, were quickly induced, and subsequently decreased by renal I/R. LXA4 pretreatment improved renal I/R-induced renal function impairment and renal damage and inhibited inflammatory responses and oxidative stresses in mice kidneys. Notably, LXA4 inhibited I/R-induced the activation of TLR4 signal pathway including decreased phosphorylation of TAK1, p36, and p65, but did not affect TLR4 and p-IRAK-1. The analysis of transcriptomic sequencing data and immunoblotting suggested that innate immune signal molecules interleukin-1 receptor-associated kinase-M (IRAK-M) and immunoresponsive gene 1 (IRG1) might be the key targets of LXA4. Further, the knockout of IRG1 or IRAK-M abolished the beneficial effects of LXA4 on IRI-AKI. In addition, IRG1 deficiency reversed the up-regulation of IRAK-M by LXA4, while IRAK-M knockout had no impact on the IRG1 expression, indicating that IRAK-M is a downstream molecule of IRG1. Mechanistically, we found that LXA4-promoted IRG1-itaconate not only enhanced Nrf2 activation and increased HO-1 and NQO1, but also upregulated IRAK-M, which interacted with TRAF6 by competing with IRAK-1, resulting in deactivation of TLR4 downstream signal in IRI-AKI. These data suggested that LXA4 protected against IRI-AKI via promoting IRG1/Itaconate-Nrf2 and IRAK-M-TRAF6 signaling pathways, providing the rationale for a novel strategy for preventing and treating IRI-AKI.

Site 1 protease aggravates acute kidney injury by promoting tubular epithelial cell ferroptosis through SIRT3-SOD2-mtROS signaling

Ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) is a common clinical syndrome with high morbidity and mortality. Ferroptosis, a newly discovered form of oxidative cell death, is involved in the pathogenesis of renal I/R injury; however, the underlying mechanism remains to be explored. Here, we reported that site 1 protease (S1P) promotes ischemic kidney injury by regulating ferroptotic cell death of tubular epithelial cells. S1P abundance was measured in hypoxia/reoxygenation (H/R)-treated Boston University mouse proximal tubular (BUMPT) cells and I/R-induced murine kidney tissue. S1P expression in BUMPT cells and kidneys was initially activated by hypoxic stimulation, accompanied by the ferroptotic response. Blocking S1P blunted H/R-induced ferroptotic cell death, which also restored sirtuin 3 (SIRT3) expression and superoxide dismutase 2 (SOD2) activity in BUMPT cells. Next, inhibition of S1P expression restored I/R-suppressed SIRT3 abundance, SOD2 activity and reduced the elevated level of mitochondria reactive oxygen species (mtROS), which attenuated tubular cell ferroptosis and renal I/R injury. In conclusion, S1P promoted renal tubular epithelial cell ferroptosis under I/R status by activating SIRT3-SOD2-mtROS signaling, thereby accelerating kidney injury. Thus, targeting S1P signaling may serve as a promising strategy for I/R kidney injury.

Development and validation of a risk model for hospital-acquired venous thrombosis: the Medical Inpatients Thrombosis and Hemostasis study

BACKGROUND

Regulatory organizations recommend assessing hospital-acquired (HA) venous thromboembolism (VTE) risk for medical inpatients.

OBJECTIVES

To develop and validate a risk assessment model (RAM) for HA-VTE in medical inpatients using objective and assessable risk factors knowable at admission.

METHODS

The development cohort included people admitted to medical services at the University of Vermont Medical Center (Burlington, Vermont) between 2010 and 2019, and the validation cohorts included people admitted to Hennepin County Medical Center (Minneapolis, Minnesota), University of Michigan Medical Center (Ann Arbor, Michigan), and Harris Health Systems (Houston, Texas). Individuals with VTE at admission, aged <18 years, and admitted for <1 midnight were excluded. We used a Bayesian penalized regression technique to select candidate HA-VTE risk factors for final inclusion in the RAM.

RESULTS

The development cohort included 60 633 admissions and 227 HA-VTE, and the validation cohorts included 111 269 admissions and 651 HA-VTE. Seven HA-VTE risk factors with t statistics ≥1.5 were included in the RAM: history of VTE, low hemoglobin level, elevated creatinine level, active cancer, hyponatremia, increased red cell distribution width, and malnutrition. The areas under the receiver operating characteristic curve and calibration slope were 0.72 and 1.10, respectively. The areas under the receiver operating characteristic curve and calibration slope were 0.70 and 0.93 at Hennepin County Medical Center, 0.70 and 0.87 at the University of Michigan Medical Center, and 0.71 and 1.00 at Harris Health Systems, respectively. The RAM performed well stratified by age, sex, and race.

CONCLUSION

We developed and validated a RAM for HA-VTE in medical inpatients. By quantifying risk, clinicians can determine the potential benefits of measures to reduce HA-VTE.

Impact of renal recovery on in-hospital and post-discharge mortality

OBJECTIVE

To verify the impact of renal recovery on mortality in non-critically ill patients with acute kidney injury.

METHOD

A prospective cohort study was carried out in a public hospital in the Federal District with patients with acute kidney injury admitted to a non-critical care unit. Renal recovery was assessed based on the ratio of serum creatinine to baseline creatinine and the patient was followed up for 6 months. Mortality was assessed during hospitalization and after discharge.

RESULTS

Of the 90 patients with hospital-acquired kidney injury, renal recovery was identified in 34.1% to 75% of cases, depending on the time of assessment, considering a follow-up period of up to 6 months. Recovery of renal function during follow-up had an impact on in-hospital mortality [95% CI 0.15 (0.003 - 0.73; p = 0019).

CONCLUSION

Recovery of renal function has been shown to be a protective factor for mortality in patients admitted to the non-critical care unit. Early identification of kidney damage and monitoring of physiological and laboratory variables proved to be fundamental in identifying the severity of the disease and reducing mortality.

LncRNA 152 attenuates lipopolysaccharide-induced acute kidney injury in rats by regulating the FGF23/Klotho/MAPK axis

AIM

This study aimed to explore the effect and related mechanisms of LncRNA 152 in acute kidney injury (AKI).

METHODS

QRT-PCR was used to detect the expression of LncRNA 152, FGF23 and Klotho in the serum of patients with AKI. Subsequently, Sprague Dawley (SD) rats were induced into AKI animal model by lipopolysaccharide (LPS). Then, H&E staining was performed to observe the pathological changes in the rat kidney tissues; qRT-PCR to detect the expression of LncRNA 152, FGF23 and Klotho in the rat kidney tissues; biochemical assay and ELISA to assess the levels of renal function indexes and inflammatory factors in rat serum, as well as oxidative stress indexes in kidney tissues; and western blot to measure the protein expressions of FGF23, Klotho, p-p38 and p38 in rat kidney tissues.

RESULTS

LncRNA 152 was significantly down-regulated in serum of AKI patients and kidney tissues of AKI rats. In AKI patients, LncRNA 152 was negatively correlated with FGF23 expression while positively correlated with Klotho expression. LncRNA 152 overexpression reduced the levels of blood urea nitrogen (BUN), creatinine (Cr) and cystatin C (Cys-C) and inflammatory factors in serum of AKI rats and attenuated pathological damage and oxidative stress of kidney tissues. In addition, LncRNA 152 overexpression also decreased FGF23 expression and p-p38/p38 ratio while up-regulated Klotho expression in the kidney tissues of AKI rats.

CONCLUSION

LncRNA 152 attenuates oxidative stress and inflammatory responses by regulating the FGF23/Klotho axis and inhibiting the MAPK signalling pathway in rat kidney tissues, thereby ameliorating LPS-induced AKI.

Recovery after AKI: Effects on outcomes over 15 years

PURPOSE

To examine the effect of kidney recovery on mortality, dialysis and kidney transplantation up to 15 years after AKI.

MATERIALS AND METHODS

We studied 29,726 survivors of critical illness and compared these outcomes stratified by AKI and recovery status at hospital discharge. Kidney recovery was defined as a return of serum creatinine to ≤150% of baseline without dialysis prior to hospital discharge.

RESULTS

Overall AKI occurred in 59.2% in which two thirds developed stage 2-3 AKI. Recovery rate of AKI at hospital discharge was 80.8%. Patients who did not recover experienced the worst 15-year mortality compared to those who recovered and those without AKI (57.8% vs 45.2% vs 30.3%, p < 0.001). This pattern was also found in subgroups of patients with suspected sepsis-associated (57.1% vs 47.9% vs 36.5%, p < 0.001) and cardiac surgery-associated AKI (60.1% vs 41.8% vs 25.9%, p < 0.001). The rates of dialysis and transplantation at 15 years were low and not associated with recovery status.

CONCLUSIONS

Recovery of AKI in critically ill patients at hospital discharge had an effect on long-term mortality for up to 15 years. These results have implications for acute care, follow-up and choice of endpoints for clinical trials.

Traumatic injuries to the renal blood vessels and in-hospital renal complications in patients with penetrating or blunt trauma

Background

Traumatic injuries to renal blood vessels (IRBV) can have significant consequences for patients, impacting their mortality, morbidity, and quality of life.

Objective

This study aimed to compare trauma types and injury characteristics, vital signs, and outcomes in patients with and without IRBV (nIRBV) and examine whether IRBV and pre-existing renal dysfunction affected the likelihood of in-hospital renal complications (iHRC).

Materials and Methods

After identifying penetrating and blunt trauma victims with IRBV in the National Trauma Data Bank, patient demographics, injury-related variables, treatment outcomes, and deaths under care were analyzed and compared.

Results

Of the 994,184 trauma victims, 610 (0.6%) experienced IRBV. Victims in the IRBV group (IRBVG) had a significantly higher frequency of penetrating injuries (19.5% vs. 9.2%, P < 0.001) and higher injury severity score (ISS ≥25, 61.5% vs. 6.7%). Most injuries in both groups were unintentional, although a higher frequency of assault was noted in the IRBVG. The incidence of iHRC was higher in the IRBVG (6.6%) than in the nIRBVG (0.4%; P < 0.001). The IRBV {OR = 3.5 [95% CI = (2.4-5.0)]}, preexisting renal disorders {OR = 2.5 [95% CI = (2.1-2.9)]}, and in-hospital cardiac arrest {OR = 8.6 [95% CI = (7.7-9.5)]} were found to be among the factors associated with a higher risk of iHRC.

Conclusions

IRBV and pre-existing renal disorders considerably increased the risk of developing iHRC. Due to the long- and short-term consequences of associated cardiovascular, renal, and hemodynamic complications, victims of IRBV require specialized renal management and close monitoring.

Bibliometric and visual analysis of machine learning-based research in acute kidney injury worldwide

Background

Acute kidney injury (AKI) is a serious clinical complication associated with adverse short-term and long-term outcomes. In recent years, with the rapid popularization of electronic health records and artificial intelligence machine learning technology, the detection rate and treatment of AKI have been greatly improved. At present, there are many studies in this field, and a large number of articles have been published, but we do not know much about the quality of research production in this field, as well as the focus and trend of current research.

Methods

Based on the Web of Science Core Collection, studies reporting machine learning-based AKI research that were published from 2013 to 2022 were retrieved and collected after manual review. VOSviewer and other software were used for bibliometric visualization analysis, including publication trends, geographical distribution characteristics, journal distribution characteristics, author contributions, citations, funding source characteristics, and keyword clustering.

Results

A total of 336 documents were analyzed. Since 2018, publications and citations have increased dramatically, with the United States (143) and China (101) as the main contributors. Regarding authors, Bihorac, A and Ozrazgat-Baslanti, T from the Kansas City Medical Center have published 10 articles. Regarding institutions, the University of California (18) had the most publications. Approximately 1/3 of the publications were published in Q1 and Q2 journals, of which Scientific Reports (19) was the most prolific journal. Tomašev et al.'s study that was published in 2019 has been widely cited by researchers. The results of cluster analysis of co-occurrence keywords suggest that the construction of AKI prediction model related to critical patients and sepsis patients is the research frontier, and XGBoost algorithm is also popular.

Conclusion

This study first provides an updated perspective on machine learning-based AKI research, which may be beneficial for subsequent researchers to choose suitable journals and collaborators and may provide a more convenient and in-depth understanding of the research basis, hotspots and frontiers.

Lower serum chloride concentrations are associated with an increased risk of death in ICU patients with acute kidney injury: an analysis of the MIMIC-IV database

BACKGROUND

The association between baseline serum chloride levels and mortality in patients with severe acute kidney injury (AKI) is unknown. Our aim was to investigate the relationship between baseline blood chloride levels and 28-day mortality in patients with AKI admitted to the ICU and to detect possible effect modifiers in this population.

METHODS

AKI patients with severe critical illness were extracted from the MIMIC-IV. During ICU admission, chloride levels were measured for the first time. Our primary outcome was 28-day mortality in patients with AKI after 24 hours in the ICU. Multivariable logistic regression was used to examine the association between three groups of chloride levels and 28-day mortality, and logistic regression with restricted cubic spline was applied to detect the non-linear trendy.

RESULTS

A total of 24,166 patients with critically ill AKI were included in this retrospective cohort study. The total 28-day mortality rate in the ICU was 15.9%. Overall, there was a U-shaped relationship between baseline serum chloride levels and 28-day mortality (non-linear P<0.001). Accordingly, patients with low serum chloride (<96 mEq/L) had a significantly increased risk of death compared to patients with normal serum chloride (96-108 meq/L) (adjusted OR=1.94, 95% CI: 1.68-2.24, P<0.001). None of the variables, including age, gender, 24-hour fluid intake, continuous renal replacement therapy, ventilation, Atrial fibrillation, Sequential Organ Failure Assessment score, whether to measure lactate and AKI stage, significantly modified the association between lower chloride levels and 28-day mortality.

CONCLUSIONS

Low serum chloride levels at baseline were associated with death at 28 days in intensive illnesses with AKI.

Stem Cells in Kidney Ischemia: From Inflammation and Fibrosis to Renal Tissue Regeneration

Ischemic nephropathy consists of progressive renal function loss due to renal hypoxia, inflammation, microvascular rarefaction, and fibrosis. We provide a literature review focused on kidney hypoperfusion-dependent inflammation and its influence on renal tissue's ability to self-regenerate. Moreover, an overview of the advances in regenerative therapy with mesenchymal stem cell (MSC) infusion is provided. Based on our search, we can point out the following conclusions: 1. endovascular reperfusion is the gold-standard therapy for RAS, but its success mostly depends on treatment timeliness and a preserved downstream vascular bed; 2. anti-RAAS drugs, SGLT2 inhibitors, and/or anti-endothelin agents are especially recommended for patients with renal ischemia who are not eligible for endovascular reperfusion for slowing renal damage progression; 3. TGF-β, MCP-1, VEGF, and NGAL assays, along with BOLD MRI, should be extended in clinical practice and applied to a pre- and post-revascularization protocols; 4. MSC infusion appears effective in renal regeneration and could represent a revolutionary treatment for patients with fibrotic evolution of renal ischemia.

Fibroblast growth factor 10 ameliorates renal ischaemia-reperfusion injury by attenuating mitochondrial damage

Ischaemia-reperfusion (I/R) injury is one of the leading causes of acute kidney injury (AKI). Its pathologic mechanism is quite complex, involving oxidative stress, inflammatory response, autophagy, and apoptosis. Fibroblast growth factor 10 (FGF10) and 5-hydroxydecanoate (5-HD) play essential roles in kidney injury. Rats were divided into four groups: (i) sham group, sham-operated animals with an unconstructed renal artery; (ii) I/R group, kidneys were subjected to 50 min of ischaemia followed by reperfusion for 2 days; (iii) I/R + FGF10 group, animals treated with 0.5 mg/kg FGF10 (i.p.) 1 h before ischaemia; and (iv) 5-HD group, animals treated with 5 mg/kg 5-HD (i.m.) 30 min before FGF10 treatment. Renal injury, apoptosis damage, mitochondrial oxidative damage, mitochondrial membrane potential (MMP), and expression of the ATP-sensitive K+ (KATP) channel subunit Kir6.2 were evaluated. FGF10 treatment significantly alleviated I/R-induced elevation in the serum creatinine level and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling-positive tubular cells in the kidney. In addition, FGF10 dramatically ameliorated renal mitochondrial-related damage, including reducing mitochondrial-dependent apoptosis, alleviating oxidative stress, maintaining the mitochondrial membrane potential, and opening the mitochondrial KATP channels. The protective effect of FGF10 was significantly compromised by the ATP-dependent potassium channel blocker 5-HD. Our data suggest that FGF10 offers effective protection against I/R and improves animal survival by attenuating mitochondrial damage.

Long-Term Consequences of Acute Kidney Injury After Pediatric Cardiac Surgery: A Systematic Review

OBJECTIVE

The objective of this study was to evaluate the available data on long-term kidney dysfunction, hypertension, and mortality after cardiac surgery-associated acute kidney injury (AKI) in the pediatric population.

STUDY DESIGN

PubMed/MEDLINE, Embase, Scopus, and reference lists of relevant articles were searched for eligible studies published from inception through March 2022. Long-term outcomes after pediatric cardiac surgery complicated by AKI and those without were investigated.

RESULTS

We identified 14 studies published between 2013 and 2022 that included a total of 6701 patients (AKI: 1376 patients; no AKI: 5325 patients). These studies used different well-established classifications to define AKI. All the studies suggested that AKI after heart surgery is common in the pediatric patient population and reported a potential link between cardiac surgery-associated AKI and important clinical outcomes. However, only 4 out of 11 studies found a strong association between (absence of recovery from) cardiac surgery-associated AKI and risk of developing chronic kidney disease, and 3 out of 5 studies found a significant increase in mortality rates for pediatric patients who developed AKI after cardiac surgery. Only 1 out of 4 studies found an association between AKI and hypertension at 12 months postoperatively, but found no association at later follow-up times.

CONCLUSIONS

Although there is a trend, evidence on the long-term consequences of cardiac surgery-associated AKI in the pediatric population is mixed. Genetic syndromes, preexisting kidney disease, univentricular or cyanotic heart conditions, and/or high-complexity surgery may be more important for the development of kidney dysfunction by adolescence and early adulthood. Regardless, these children may benefit from a long-term kidney follow-up.

Development and validation of short-term renal prognosis prediction model in diabetic patients with acute kidney injury

OBJECTIVE

Diabetes is a major cause of the progression of acute kidney injury (AKI). Few prediction models have been developed to predict the renal prognosis in diabetic patients with AKI so far. The aim of this study was to develop and validate a predictive model to identify high-risk individuals with non-recovery of renal function at 90 days in diabetic patients with AKI.

METHODS

Demographic data and related laboratory indicators of diabetic patients with AKI in the First Affiliated Hospital of Guangxi Medical University from January 31, 2012 to January 31, 2022 were retrospectively analysed, and patients were followed up to 90 days after AKI diagnosis. Based on the results of Logistic regression, a model predicting the risk of non-recovery of renal function at 90 days in diabetic patients with AKI was developed and internal validated. Consistency index (C-index), calibration curve, and decision curve analysis were used to evaluate the differentiation, accuracy, and clinical utility of the prediction model, respectively.

RESULTS

A total of 916 diabetic patients with AKI were enrolled, with a male to female ratio of 2.14:1. The rate of non-recovery of renal function at 90 days was 66.8% (612/916). There were 641 in development cohort and 275 in validation cohort (ration of 7:3). In the development cohort, a prediction model was developed based on the results of Logistic regression analysis. The variables included in the model were: diabetes duration (OR = 1.022, 95% CI  1.012-1.032), hypertension (OR = 1.574, 95% CI 1.043-2.377), chronic kidney disease (OR = 2.241, 95% CI 1.399-3.591), platelet (OR = 0.997, 95% CI 0.995-1.000), 25-hydroxyvitamin D3 (OR = 0.966, 95% CI  0.956-0.976), postprandial blood glucose (OR = 1.104, 95% CI 1.032-1.181), discharged serum creatinine (OR = 1.003, 95% CI 1.001-1.005). The C-indices of the prediction model were 0.807 (95% CI 0.738-0.875) and 0.803 (95% CI 0.713-0.893) in the development and validation cohorts, respectively. The calibration curves were all close to the straight line with slope 1. The decision curve analysis showed that in a wide range of threshold probabilities.

CONCLUSION

A prediction model was developed to help predict short-term renal prognosis of diabetic patients with AKI, which has been verified to have good differentiation, calibration degree and clinical practicability.

Incidence and Recovery of Acute Kidney Injury in Diabetic and Nondiabetic Patients with Foot Infections

BACKGROUND

The aim of this study was to evaluate the incidence and recovery of acute kidney injury (AKI) in patients admitted to the hospital with and without diabetes mellitus (DM) with foot infections.

METHODS

We retrospectively reviewed 294 patients with DM and 88 without DM admitted to the hospital with foot infections. The Kidney Disease: Improving Global Outcomes guidelines were used to define AKI. Recovery was divided into three categories: full, partial, and no recovery within 90 days of the index AKI.

RESULTS

The AKI incidence was 3.0 times higher in patients with DM (DM 48.5% versus no DM 23.9%; 95% confidence interval [CI], 1.74-5.19; P < .01). Acute kidney injury incidence was similar at each stage in people with and without DM (stage 1, DM 58.1% versus no DM 47.6%; stage 2, DM 23.3% versus no DM 33.3%, and stage 3, DM 18.6% versus no DM 19.1%). Twenty-nine patients with diabetes had a second AKI event and four had a third event. In patients without DM, one patient had a second AKI. Cumulative AKI incidence was 4.7 times higher in people with DM (DM 60.9% versus no DM 25.0%; 95% CI, 2.72-8.03; P < .01). Patients with diabetes progressed to chronic kidney disease or in chronic kidney disease stage 39.4% of the time. Patients without diabetes progressed 16.7% of the time, but this trend was not significant (P = .07). Complete recovery was 3.8 times more likely in patients without diabetes (95% CI, 1.26-11.16; P = .02).

CONCLUSIONS

Acute kidney injury incidence is higher in patients with diabetes, and complete recovery after an AKI is less likely compared to patients without diabetes.

Prognosis of patients with heart disease with acute kidney injury undergoing dialysis treatment

OBJECTIVES

to verify the relationship of cardiovascular diseases with acute kidney injury and assess the prognosis of patients in renal replacement therapy.

METHODS

a cohort study, carried out in a public hospital specialized in cardiology. Treatment, comorbidities, duration of treatment, laboratory tests, discharge and deaths were analyzed.

RESULTS

of the 101 patients, 75 (74.3%) received non-dialysis treatment. The most frequent cardiological diagnoses were hypertension, cardiomyopathies and coronary syndrome. Hospitalization in patients undergoing dialysis was 18 days, hemoglobin <10.5g/dl and anuria in the first days of hospitalization contributed to the type of treatment. Each increase in hemoglobin units from the first day of hospitalization decreases the chance of dialysis by 19.2%. There was no difference in mortality.

CONCLUSIONS

the main cardiological diseases were not predictive of dialysis indication, and clinical treatment was the most frequent. Anuria and anemia were predictors for dialysis treatment.

Prognostic Value of Systemic Immune-Inflammation Index among Critically Ill Patients with Acute Kidney Injury: A Retrospective Cohort Study

Inflammation plays a significant role in the occurrence and development of acute kidney injury (AKI). Evidence regarding the prognostic effect of the systemic immune-inflammation index (SII) in critically ill patients with AKI is scarce. The aim of this study was to assess the association between SII and all-cause mortality in these patients. Detailed clinical data were extracted from the Medical Information Mart for Intensive Care Database (MIMIC)-IV. The primary outcome was set as the in-hospital mortality. A total of 10,764 AKI patients were enrolled in this study. The restricted cubic splines analyses showed a J-shaped curve between SII and the risk of in-hospital and ICU mortality. After adjusting for relevant confounders, multivariate Cox regression analysis showed that both lower and higher SII levels were associated with an elevated risk of in-hospital all-cause mortality. A similar trend was observed for ICU mortality. In summary, we found that the SII was associated in a J-shaped pattern with all-cause mortality among critically ill patients with AKI. SII appears to be have potential applications in the clinical setting as a novel and easily accessible biomarker for predicting the prognosis of AKI patients.

Recovery of Renal Function in Clinical Patients with Acute Kidney Injury: Impact on Mortality

Objective: To assess the different renal function recovery patterns and their impact on the mortality of non-critical patients with hospital-acquired Acute Kidney Injury. Design: A prospective cohort study was conducted from January 2017 to December 2019. Methods: The patients included were those with Acute Kidney Injury acquired during their hospitalization, identified from Kidney Disease: Improving Global Outcomes (KDIGO). Renal function recovery was calculated through the serum creatinine ratio in relation to baseline creatinine at the renal function evaluation moment. A descriptive analysis of the results was performed, and the Backward method was adopted for the multivariate analysis. Results: One-thousand five-hundred and forty-six patients were evaluated in the medical clinic and 202 (13.06%) were identified to have Acute Kidney Injury; among them, renal function recovery varied over the six months of follow-up with greater expressiveness in the second and third months (from 61.02% to 62.79%). Recovery was a protective factor against in-hospital death in the first (OR 0.24; 95% CI 0.09–0.61; p-value = 0.038) and sixth month of follow-up (OR 0.24; 95% CI 0.09–0.61; p-value = 0.003). Conclusions: The incidence of renal function recovery varied throughout the six months of follow-up and reached progressively high levels from the second to the third months. Renal recovery was a protective factor against mortality during the follow-up period.

Acute kidney injury-attributable mortality in critically ill patients with sepsis

Background

To assess whether acute kidney injury (AKI) is independently associated with hospital mortality in ICU patients with sepsis, and estimate the excess AKI-related mortality attributable to AKI.

Methods

We analyzed adult patients from two distinct retrospective critically ill cohorts: (1) Medical Information Mart for Intensive Care IV (MIMIC IV; n = 15,610) cohort and (2) Wenzhou (n = 1,341) cohort. AKI was defined by Kidney Disease: Improving Global Outcomes (KDIGO) criteria. We applied multivariate logistic and linear regression models to assess the hospital and ICU mortality, hospital length-of-stay (LOS), and ICU LOS. The excess attributable mortality for AKI in ICU patients with sepsis was further evaluated.

Results

AKI occurred in 5,225 subjects in the MIMIC IV cohort (33.5%) and 494 in the Wenzhou cohort (36.8%). Each stage of AKI was an independent risk factor for hospital mortality in multivariate logistic regression after adjusting for baseline illness severity. The excess attributable mortality for AKI was 58.6% (95% CI [46.8%-70.3%]) in MIMIC IV and 44.6% (95% CI [12.7%-76.4%]) in Wenzhou. Additionally, AKI was independently associated with increased ICU mortality, hospital LOS, and ICU LOS.

Conclusion

Acute kidney injury is an independent risk factor for hospital and ICU mortality, as well as hospital and ICU LOS in critically ill patients with sepsis. Thus, AKI is associated with excess attributable mortality.

Early Effects of Extracellular Vesicles Secreted by Adipose Tissue Mesenchymal Cells in Renal Ischemia Followed by Reperfusion: Mechanisms Rely on a Decrease in Mitochondrial Anion Superoxide Production

Acute kidney injury (AKI) caused by ischemia followed by reperfusion (I/R) is characterized by intense anion superoxide (O₂^•−) production and oxidative damage. We investigated whether extracellular vesicles secreted by adipose tissue mesenchymal cells (EVs) administered during reperfusion can suppress the exacerbated mitochondrial O₂^•− formation after I/R. We used Wistar rats subjected to bilateral renal arterial clamping (30 min) followed by 24 h of reperfusion. The animals received EVs (I/R + EVs group) or saline (I/R group) in the kidney subcapsular space. The third group consisted of false-operated rats (SHAM). Mitochondria were isolated from proximal tubule cells and used immediately. Amplex Red™ was used to measure mitochondrial O₂^•− formation and MitoTracker™ Orange to evaluate inner mitochondrial membrane potential (Δψ). In vitro studies were carried out on human renal proximal tubular cells (HK-2) co-cultured or not with EVs under hypoxic conditions. Administration of EVs restored O₂^•− formation to SHAM levels in all mitochondrial functional conditions. The gene expression of catalase and superoxide dismutase-1 remained unmodified; transcription of heme oxygenase-1 (HO-1) was upregulated. The co-cultures of HK-2 cells with EVs revealed an intense decrease in apoptosis. We conclude that the mechanisms by which EVs favor long-term recovery of renal structures and functions after I/R rely on a decrease of mitochondrial O₂^•− formation with the aid of the upregulated antioxidant HO-1/Nuclear factor erythroid 2-related factor 2 system, thus opening new vistas for the treatment of AKI.

Acute Kidney Injury: Biomarker-Guided Diagnosis and Management

Acute kidney injury (AKI) is a common clinical syndrome that is characterized by abnormal renal function and structure. The Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference in 2019 reviewed the stages of AKI and the definitions of AKI-related terminologies, and discussed the advances in the last decade. Along with serum creatinine level and urine output, more accurate novel biomarkers for predicting AKI are being applied for the early detection of renal dysfunction. A literature search was conducted in PubMed, Scopus, Medline, and ClinicalTrials.gov using the terms AKI and biomarker, combined with diagnosis, management, or prognosis. Because of the large volume of data (160 articles) published between 2005 and 2022, representative literature was chosen. A number of studies have demonstrated that new biomarkers are more sensitive in detecting AKI in certain populations than serum creatinine and urine output according to the recommendations from the Acute Disease Quality Initiative Consensus Conference. To be specific, there is a persistently unresolved need for earlier detection of patients with AKI before AKI progresses to a need for renal replacement therapy. Biomarker-guided management may help to identify a high-risk group of patients in progression to severe AKI, and decide the initiation time to renal replacement therapy and optimal follow-up period. However, limitations such as biased data to certain studied populations and absence of cutoff values need to be solved for worldwide clinical use of biomarkers in the future. Here, we provide a comprehensive review of biomarker-based AKI diagnosis and management and highlight recent developments.

Cost-Effectiveness Analysis of New Beta-Lactam Beta-Lactamase Inhibitor Antibiotics Versus Colistin for the Treatment of Carbapenem-Resistant Infections

Introduction: Carbapenem-resistant organisms (CROs) present a serious public health problem. Limited treatment options has led to increased use of colistin and polymyxin. Since 2014, the US Food and Drug Administration approved 4 new beta-lactam beta-lactamase inhibitor (BLBLI) combination antibiotics with activity against CROs. These new antibiotics have been shown to be more effective and less toxic than colistin and polymyxin but are considerably more expensive. This study evaluated the cost-effectiveness of the new BLBLIs versus colistin-based therapy for the treatment of CROs. Methods: A decision-tree microsimulation model was used to evaluate the cost effectiveness of the new BLBLIs versus colistin-based therapy for the treatment of CROs. Treatment groups differed in risk of mortality and risk of an acute kidney injury (AKI). The relative risk of mortality was determined by creating a meta-analysis comparing new BLBLIs to colistin. Cost inputs included medication costs and the cost to treat an AKI. The primary outcomes include quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). Model inputs included: clinical outcomes and adverse events (30-day mortality and AKI); cost of treatment and adverse drug events; and health utilities. A 3% discount was applied for outcomes. A lifetime horizon was used from the perspective of the US healthcare system with a willingness-to-pay (WTP) threshold of $100 000. A sensitivity analysis was done to incorporate uncertainty. Results: The meta-analysis found the treatment with a new BLBLI was associated with a 50% decrease in the relative risk of 30-day mortality compared to colistin (RR 0.47, 95% CI 0.25-0.88). Treatment with a new BLBLI cost $16 200 and produced 11.5 QALYs, on average. The average colistin based regimen cost $3500 and produced 8.3 QALYs. The new BLBLIs were determined to be cost-effective with an ICER of $3900 per QALY gained. Treatment with a BLBLI remained cost-effective under all uncertainty scenarios tested. Conclusion: New BLBLIs are cost-effective compared to colistin for the treatment of CROs and are associated with improved mortality and fewer AKI events. The use of colistin should be reserved for cases where new BLBLIs are not available or there is documented resistance to these new antibiotics.

Stratifin promotes renal dysfunction in ischemic and nephrotoxic AKI mouse models via enhancing RIPK3-mediated necroptosis

Stratifin (SFN) is a member of the 14-3-3 family of highly conserved soluble acidic proteins, which regulates a variety of cellular activities such as cell cycle, cell growth and development, cell survival and death, and gene transcription. Acute kidney injury (AKI) is prevalent disorder characterized by inflammatory response, oxidative stress, and programmed cell death in renal tubular epithelial cells, but there is still a lack of effective therapeutic target for AKI. In this study, we investigated the role of SFN in AKI and the underlying mechanisms. We established ischemic and nephrotoxic AKI mouse models caused by ischemia-reperfusion (I/R) and cisplatin, respectively. We conducted proteomic and immunohistochemical analyses and found that SFN expression levels were significantly increased in AKI patients, cisplatin- or I/R-induced AKI mice. In cisplatin- or hypoxia/reoxygenation (H/R)-treated human proximal tubule epithelial cells (HK2), we showed that knockdown of SFN significantly reduced the expression of kidney injury marker Kim-1, attenuated programmed cell death and inflammatory response. Knockdown of SFN also significantly alleviated the decline of renal function and histological damage in cisplatin-caused AKI mice in vivo. We further revealed that SFN bound to RIPK3, a key signaling modulator in necroptosis, to induce necroptosis and the subsequent inflammation in cisplatin- or H/R-treated HK2 cells. Overexpression of SFN increased Kim-1 protein levels in cisplatin-treated MTEC cells, which was suppressed by RIPK3 knockout. Taken together, our results demonstrate that SFN that enhances cisplatin- or I/R-caused programmed cell death and inflammation via interacting with RIPK3 may serve as a promising therapeutic target for AKI treatment.

Comparative Evaluation of Two NGAL Automated Immunoassays in Urine and Plasma

BACKGROUND

Acute kidney injury (AKI), a frequent and serious complication of hospitalized patients, is associated with increased mortality and morbidity. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for the early identification of AKI. We report a comparative laboratory verification of the Abbott Diagnostics (ARCHITECT® urine NGAL) and BioPorto Diagnostics (NGAL TestTM) assays including an assessment of the Abbott assay's performance in EDTA plasma.

METHODS

Intra-/interbatch imprecision, linearity, recovery, and limit of quantitation (LoQ) were assessed and an interassay comparison performed (n = 51). Between-laboratory agreement was assessed against other laboratories using the Abbott (n = 48) and BioPorto (n = 94) assays. Plasma NGAL (pNGAL) levels were measured in non-AKI patients with a range of estimated glomerular filtration rates (n = 80).

RESULTS

Coefficients of variation (CVs) for intra- and interbatch imprecision were 0.7%-12.4% and 1.9%-27.5% for the BioPorto assay, respectively, and 1.4%-6.3%/3.4%-6.8%, respectively, for the Abbott assay. The BioPorto assay exhibited a higher LoQ (27.5 ng/mL vs 1.2 ng/mL). Both assays were linear over the range 5-6000 ng/mL. Recovery of recombinant NGAL was 113.1 ± 7.1% and 96.5 ± 7.8% for the Abbott and BioPorto assays, respectively. On average, the Abbott assay gave results 9.2% lower than the BioPorto assay. Mean differences of 0.2% (Abbott) and 20.2% (BioPorto) were observed in the between-laboratory comparison. In patients without AKI, pNGAL levels were inversely proportional to eGFR.

CONCLUSIONS

Performance of the Abbott and BioPorto assays was similar although the latter performed less well at lower NGAL concentrations. The Abbott assay tended to yield lower results, exhibited a lower LoQ and over-recovered NGAL. Although only Conformité Européenne-marked and marketed for use in urine, the Abbott assay demonstrated equivalent performance to the BioPorto assay with EDTA plasma.

Prognóstico de pacientes cardiopatas com injuria renal aguda submetidos a tratamento dialítico

RESUMO Objetivos: verificar a relação de patologias cardíacas com injuria renal aguda e avaliar o prognóstico do paciente em terapia de substituição renal. Métodos: estudo de coorte, realizado em hospital público especializado em cardiologia. O tratamento, comorbidades, tempo de tratamento, exames laboratoriais, alta e óbitos foram analisados. Resultados: dos 101 pacientes, 75 (74,3%) receberam tratamento não dialítico. Os diagnósticos cardiológicos mais frequentes foram hipertensão arterial, miocardiopatias e síndrome coronariana. A internação nos pacientes dialíticos foi de 18 dias, a hemoglobina <10,5g/dl e a anuria nos primeiros dias de internação contribuíram para o tipo de tratamento. Cada aumento de unidade de hemoglobina a partir do primeiro dia de internação diminui em 19,2% a chance de diálise. Não houve diferença na mortalidade. Conclusões: as principais doenças cardiológicas não foram preditivas de indicação de diálise, e o tratamento clínico foi o mais frequente. Anuria e anemia foram preditores para o tratamento dialítico.

Frequency of Renal Dysfunction and its effects on outcomes after open heart surgery

Objectives:

In this study we determined the frequency of renal dysfunction and its outcomes in terms of morbidity and mortality in patients who underwent open heart surgery at the Aga Khan University Hospital, Karachi, Pakistan.

Methods:

A total of 175 patients aged between 15-80 years having open heart Surgery(OHS) were included. Preoperative and postoperative serum creatinine (SCr) was noted and the glomerular filtration rate (GFR) calculated by Cockcroft-Gault equation. Their hospital course was charted and followed-up for 30-day.

Results:

The mean age and mean BMI were 58.1±12.6 years and 26.4±4.3 kg/m2 respectively. Females were 18.3%, out of which 51.4% hypertensive, 46.9% diabetics, 45.1% had dyslipidemia, 2.9% had preoperative renal dysfunction and 40% had moderate ejection fraction. On follow up, 30.3% developed postoperative renal dysfunction within 30-days after OHS with mean SCr and GFR as 1.6±0.7 and 56.9±24.5, respectively. In RD group more patients showed positive outcomes i.e. prolonged inotropic requirement (75.5% vs. 18%, p-value <0.005), diuretic infusion usage (47.2% vs. 3.3%, p-value <0.005), dialysis/renal replacement therapy (17% vs. 0%, p-value <0.005), requirement for prolonged ventilation (35.8% vs. 6.6%, p-value <0.005), prolonged ICU and hospital stay (15.4% vs. 1.6%, p-value <0.005 and 41.5% vs. 17.2%, p-value <0.005), sepsis (20.8% vs. 1.6%, p-value <0.005) and death (9.4% vs. 2.5%, p-value 0.05).

Conclusion:

Timely recognition of renal dysfunction, early renal replacement therapy, diuretics or dialysis and proper nutritional and inotropic support to maintain adequate hemostasis shows survival benefits.

Long-Term Preservation of Renal Function in Septic Shock Burn Patients Requiring Renal Replacement Therapy for Acute Kidney Injury

BACKGROUND

The real impact of septic shock-associated acute kidney injury (AKI) on the long-term renal outcome is still debated, and little is known about AKI-burn patients. In a cohort of burn survivors treated by continuous renal replacement therapy (CRRT) and sorbent technology (CPFA-CRRT), we investigated the long-term outcome of glomerular and tubular function.

METHODS

Out of 211 burn patients undergoing CRRT from 2001 to 2017, 45 survived, 40 completed the clinical follow-up (cumulative observation period 4067 months, median 84 months, IR 44-173), and 30 were alive on 31 December 2020. Besides creatinine and urine albumin, in the 19 patients treated with CPFA-CRRT, we determined the normalized GFR by 99mTc-DTPA (NRI-GFR) and studied glomerular and tubular urine protein markers.

RESULTS

At the follow-up endpoint, the median plasma creatinine and urine albumin were 0.99 (0.72-1.19) and 0.0 mg/dL (0.0-0.0), respectively. NRI-GFR was 103.0 mL/min (93.4-115). Four patients were diabetic, and 22/30 presented at least one risk factor for chronic disease (hypertension, dyslipidemia, and overweight). Proteinuria decreased over time, from 0.47 g/day (0.42-0.52) at 6 months to 0.134 g/day (0.09-0.17) at follow-up endpoint. Proteinuria positively correlated with the peak of plasma creatinine (r 0.6953, p 0.006) and the number of CRRT days (r 0.5650, p 0.035) during AKI course, and negatively with NRI-GFR (r -0.5545, p 0.049). In seven patients, urine protein profile showed a significant increase of glomerular marker albumin and glomerular/tubular index.

CONCLUSIONS

Burn patients who experienced septic shock and AKI treated with CRRT had a long-term expectation of preserved renal function. However, these patients were more predisposed to microalbuminuria, diabetes, and the presence of risk factors for intercurrent comorbidities and chronic renal disease.

Mortality and evolution between community and hospital-acquired COVID-AKI

Background

Acute kidney injury (AKI) is associated with poor outcomes in COVID patients. Differences between hospital-acquired (HA-AKI) and community-acquired AKI (CA-AKI) are not well established.

Methods

Prospective, observational cohort study. We included 877 patients hospitalized with COVID diagnosis at two third-level hospitals in Mexico. Primary outcome was all-cause mortality at 28 days compared between COVID patients with CA-AKI and HA-AKI. Secondary outcomes included the need for KRT, and risk factors associated with the development of CA-AKI and HA-AKI.

Results

A total of 377 patients (33.7%) developed AKI. CA-AKI occurred in 202 patients (59.9%) and HA-AKI occurred in 135 (40.1%). Patients with CA-AKI had more significant comorbidities, including diabetes (52.4% vs 38.5%), hypertension (58.4% vs 39.2%), CKD (30.1% vs 14.8%), and COPD (5.9% vs 1.4%), than those with HA-AKI. Patients’ survival without AKI was 87.1%, with CA-AKI it was 75.4%, and with HA-AKI it was 69.6%, log-rank test p < 0.001. Only age > 60 years (OR 1.12, 95% CI 1.06–1.18, p <0.001), COVID severity (OR 1.09, 95% CI 1.03–1.16, p = 0.002), the need in mechanical lung ventilation (OR 1.67, 95% CI 1.56–1.78, p <0.001), and HA-AKI stage 3 (OR 1.16, 95% CI 1.05–1.29, p = 0.003) had a significant increase in mortality. The presence of CKD (OR 1.48, 95% CI 1.391.56, p < 0.001), serum lymphocytes < 1000 μL (OR 1.03, 95% CI 1.00–1.07, p = 0.03), the need in mechanical lung ventilation (OR 1.06, 95% CI 1.02–1.11, p = 0.003), and CA-AKI stage 3 (OR 1.37, 95% CI 1.29–1.46, p < 0.001) were the only variables associated with a KRT start.

Conclusions

We found that COVID patients who are complicated by CA-AKI have more comorbidities and worse biochemical parameters at the time of hospitalization than HA-AKI patients, but despite these differences, their probability of dying is similar.

Biomarkers of persistent renal vulnerability after acute kidney injury recovery

Acute kidney injury (AKI) is a risk factor for new AKI episodes, chronic kidney disease, cardiovascular events and death, as renal repair may be deficient and maladaptive, and activate proinflammatory and profibrotic signals. AKI and AKI recovery definitions are based on changes in plasma creatinine, a parameter mostly associated to glomerular filtration, but largely uncoupled from renal tissue damage. The evolution of structural and functional repair has been incompletely described. We thus aimed at identifying subclinical sequelae persisting after recovery from cisplatin-induced AKI in rats. Compared to controls, after plasma creatinine recovery, post-AKI kidneys showed histological alterations and attendant susceptibility to new AKI episodes. Tubular function (assessed by the furosemide stress test, FST) also remained affected. Lingering parenchymal and functional subclinical alterations were paralleled by tapering, but abnormally high levels of urinary albumin, transferrin, insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinases-2 (TIMP-2) and, especially, the [TIMP-2]*[IGFBP7] product. As subclinical surrogates of incomplete renal recovery, the FST and the urinary [TIMP-2]*[IGFBP7] product provide two potential diagnostic tools to monitor the sequelae and kidney vulnerability after the apparent recovery from AKI.

Acute Kidney Injury within an Enhanced Recovery after Surgery (ERAS) Program for Colorectal Surgery

BACKGROUND

We aimed to determine the prevalence, risk factors, and outcomes of acute kidney injury (AKI) within an ERAS program for colorectal surgery (CRS).

METHODS

This is a retrospective case-control study conducted from March 2016 to September 2018 at a single tertiary hospital in Singapore. All adult patients requiring CRS within our ERAS program were considered eligible. Exclusions were stage 5 chronic kidney disease or patients requiring a synchronous liver resection. The primary outcome was AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. Secondary outcomes included mortality, major complications, and hospital length of stay. Patient, surgical, and anaesthesia-related data were analysed to determine factors associated with AKI.

RESULTS

A total of 575 patients were eligible for the study. Twenty patients were excluded from the study leaving 555 patients for analysis. Mean age was 67.8 (SD 11.4) years. Seventy-four patients met the criteria for AKI (13.4%: stage 1-11.2%, stage 2-2.0%, stage 3-0.2%). One patient required renal replacement therapy (RRT). Patients with AKI had a longer length of stay (median [IQR], 11.0 [5.0-17.0] days vs 6.0 [4.0-8.0] days; P < .001), more major complications (OR, 6.55; 95% CI, 3.00-14.35, P < .001), and a trend towards higher mortality at one year (OR, 1.44; 95% CI 0.48-4.30; p = 0.511. After multivariable regression analysis, factors associated with AKI were preoperative creatinine (OR, 1.01 per 10 µmol/l; 95% CI, 1.03-1.22; P = 0.01), robotic surgery vs open surgery (OR, 0.15; 95% CI, 0.06-0.39; P < 0.001), anaesthesia duration (OR, 1.38 per hour; 95% CI, 1.22-1.55; P < 0.001), and major complications (OR, 5.55; 95% CI, 2.63-11.70; P < 0.001).

CONCLUSIONS

Within the present cohort, the implementation of an ERAS program for CRS was associated with a low prevalence of moderate to severe AKI despite a balanced intravenous fluid regimen. Patients having open surgery, longer procedures, and major complications are at increased risk of AKI.

Impact of Inhaled Oxygen on Reactive Oxygen Species Production and Oxidative Damage during Spontaneous Ventilation in a Murine Model of Acute Renal Ischemia and Reperfusion

Introduction

Acute kidney injury (AKI) affects 10% of patients following major surgery and is independently associated with extra-renal organ injury, development of chronic kidney disease, and death. Perioperative renal ischemia and reperfusion (IR) contributes to AKI by, in part, increasing production of reactive oxygen species (ROS) and leading to oxidative damage. Variations in inhaled oxygen may mediate some aspects of IR injury by affecting tissue oxygenation, ROS production, and oxidative damage. We tested the hypothesis that provision of air (normoxia) compared to 100% oxygen (hyperoxia) during murine renal IR affects renal ROS production and oxidative damage.

Methods

We administered 100% oxygen or 21% oxygen (air) to 8-9 week-old FVB/N mice and performed dorsal unilateral nephrectomy with contralateral renal ischemia/reperfusion surgery while mice spontaneously ventilated. We subjected mice to 30 minutes of ischemia and 30 minutes of reperfusion prior to sacrifice. We obtained an arterial blood gas (ABG) by performing sternotomy and left cardiac puncture. We stained the kidney with pimonidazole, a marker of tissue hypoxia; 4-HNE, a marker of ROS-production; and we measured F2-isoprostanes in homogenized tissue to quantify oxidative damage.

Results

Hyperoxia during IR increased arterial oxygen content compared to normoxia, but both groups of mice were hypoventilating at the time of ABG sampling. Renal tissue hypoxia following reperfusion was similar in both treatment groups. ROS production was similar in the cortex of mice (3.8% area in hyperoxia vs. 3.1% in normoxia, P=0.19) but increased in the medulla of hyperoxia-treated animals (6.3% area in hyperoxia vs. 4.5% in nomoxia, P=0.02). Renal F2-isoprostanes were similar in treatment groups (2.2 pg/mg kidney in hyperoxia vs. 2.1 pg/mg in normoxia, P=0.40).

Conclusions

Hyperoxia during spontaneous ventilation in murine renal IR did not appear to affect renal hypoxia following reperfusion, but hyperoxia increased medullary ROS production compared to normoxia.

Association of Acute Kidney Injury with the Risk of Dementia: A Meta-Analysis

Acute kidney injury (AKI) is associated with several adverse outcomes, including new or progressive chronic kidney disease, end-stage kidney disease, and mortality. Epidemiological studies have reported an association between AKI and dementia as a long-term adverse outcome. This meta-analysis was aimed to understand the association between AKI and dementia risk. A literature search was performed in MEDLINE and Embase databases, from inception to July 2021, to identify epidemiological studies reporting the association between AKI and dementia risk. Title and abstract followed by the full-text of retrieved articles were screened, data were extracted, and quality was assessed, using the Newcastle-Ottawa scale by two investigators independently. The primary outcome was to compute the pooled risk of dementia in AKI patients. Subgroup analysis was also performed based on age and co-morbidities. Certainty of evidence was assessed using the GRADE approach. Statistical analysis was performed using Review Manager 5.4 software. Four studies (cohort (n = 3) and case-control (n = 1)) with a total of 429,211 patients, of which 211,749 had AKI, were identified. The mean age of the patients and the follow-up period were 64.15 ± 16.09 years and 8.9 years, respectively. Included studies were of moderate to high quality. The pooled estimate revealed a significantly higher risk of dementia in AKI patients with an overall relative risk/risk ratio (RR) of 1.92 (95% CI: 1.52-2.43), p ≤ 0.00001. Dementia risk increases by 10% with one year increase in age with an RR of 1.10 (95% CI: 1.09-1.11), p < 0.00001. Subgroup analysis based on stroke as a co-morbid condition also revealed significantly higher dementia risk in AKI patients (RR 2.30 (95% CI: 1.62-3.28), p = 0.009). All-cause mortality risk was also significantly higher in AKI patients with dementia with a pooled RR of 2.11 (95% CI: 1.20-3.70), p = 0.009. The strength of the evidence was of very low certainty as per the GRADE assessment. Patients with AKI have a higher risk of dementia. Further large epidemiological studies are needed to confirm the mechanistic association.

CYR61, regulated by miR-22-3p and MALAT1, promotes autophagy in HK-2 cell inflammatory model

Background

Renal tubular epithelial cells play an important role in renal function and are a major site of injury from inflammation. Emerging evidence suggests that CYR61 is involved in the regulation of autophagy. However, there are few studies on CYR61 in nephropathy and associated inflammation. This study aimed to clarify how CYR61 regulates autophagy in human renal epithelial cells while in an inflammatory state and regulates the upstream pathway of CYR61 levels.

Methods

The human renal tubular epithelial cells (HK-2) cell line treated by lipopolysaccharide (LPS) was used as an inflammatory model of human epithelial cells. Short hairpin RNA (shRNA) was used to down-regulate CYR61, and the changes in the transcription and expression levels of related molecules, as well as the morphological changes of HK-2 cells, were detected by quantitative real time-PCR (qRT-PCR), western blot (WB), and transmission electron microscopy. Either CYR61 or MALAT1 were up-regulated by overexpression vectors, or MALAT1 was down-regulated by miR-22-3p mimics. Subsequently, the levels of CYR61, MALAT1, related inflammatory factors, and autophagy factors were measured by qPCR, WB, and enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was detected by flow cytometry and acridine-orange assay.

Results

We observed that down-regulation of CYR61 could down-regulate 1B-light chain 3 (LC3) level and inhibit autophagy in the LPS-induced inflammation model of HK-2 cells. The expression levels of CYR61, Beclin1, Atg5, LC3, interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly increased by upregulating CYR61 or MALAT1 by overexpression vector, while the expression level of p62 was significantly decreased, intracellular reactive oxygen species (ROS) content was increased, and the proportion of autophagy and apoptosis was increased. The use of miR-22-3p mimics significantly reversed the changes induced by up-regulation of CYR61 or MALAT1 at the molecular and cellular levels.

Conclusions

Our data indicated that CYR61 positively regulates autophagy of HK-2 cells under an inflammatory state, and was negatively regulated by miR-22-3p, while miR-22-3p and MALAT1 were negatively regulated by each other.

Antagonist targeting miR‑106b‑5p attenuates acute renal injury by regulating renal function, apoptosis and autophagy via the upregulation of TCF4

Acute renal injury (ARI) is a life‑threatening condition and a main contributor to end‑stage renal disease, which is mainly caused by ischemia‑reperfusion (I/R). miR‑106b‑5p is a kidney function‑related miRNA; however, whether miR‑106b‑5p regulates the progression of ARI remains unclear. The present study thus aimed to examine the effects of miR‑106b‑5p antagonist on the regulation of ARI progression. It was found that miR‑106b‑5p expression was upregulated in the renal tissue of rats with I/R‑induced ARI and in NRK‑52E rat renal proximal tubular epithelial cells subjected to hypoxia‑reoxygenation (H/R). In vitro, H/R induction suppressed the proliferation, and promoted the apoptosis and autophagy of NRK‑52E cells, whereas miR‑106b‑5p antagonist (inhibition of miR‑106b‑5p) promoted the proliferation, and attenuated the apoptosis and autophagy of NRK‑52E cells under the H/R condition. Dual luciferase reporter gene assay validated that transcription factor 4 (TCF4) was a target of miR‑106b‑5p. It was further found that TCF4 overexpression promoted the proliferation, and inhibited the apoptosis and autophagy of NRK‑52E cells subjected to H/R. Moreover, the effects of miR‑106b‑5p antagonist on NRK‑52E cell proliferation, apoptosis and autophagy were mediated through the regulation of TCF4. In vivo, miR‑106b‑5p antagonist reduced the severity of renal injury, decreased cell proliferation in renal tissues and lowered the serum creatinine (Scr) and blood urea nitrogen (BUN) levels in the blood samples from rats with I/R‑induced ARI. On the whole, the findings presented herein demonstrate that miR‑106b‑5p antagonist attenuates ARI by promoting the proliferation, and suppressing the apoptosis and autophagy of renal cells via upregulating TCF4.

Diseases of the Aorta and Kidney Disease: Conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) is an independent risk factor for the development of abdominal aortic aneurysm (AAA), as well as for cardiovascular and renal events and all-cause mortality following surgery for AAA or thoracic aortic dissection. In addition, the incidence of acute kidney injury (AKI) after any aortic surgery is particularly high, and this AKI per se is independently associated with future cardiovascular events and mortality. On the other hand, both development of AKI after surgery and the long-term evolution of kidney function differ significantly depending on the type of AAA intervention (open surgery vs. the various subtypes of endovascular repair). Current knowledge regarding AAA in the general population may not be always applicable to CKD patients, as they have a high prevalence of co-morbid conditions and an elevated risk for periprocedural complications. This summary of a Kidney Disease: Improving Global Outcomes Controversies Conference group discussion reviews the epidemiology, pathophysiology, diagnosis, and treatment of Diseases of the Aorta in CKD and identifies knowledge gaps, areas of controversy, and priorities for future research.

Organizational and financial aspects of a continuous renal replacement therapy program

Critically ill patients who develop severe acute kidney injury in the intensive care unit often require treatment with renal replacement therapies (RRTs). This complication is associated with severe morbidity and mortality and high costs, both during hospitalization and postdischarge. This article discusses the operational requirements to develop and conduct a RRT program, as well as the financial implications of this complex form of patient care. The management of these programs must occur in a context where a clear organizational and educational framework and a multidisciplinary team ensures safety, effectiveness, cost-control, and a clear quality control framework.

Fibrosis, the Bad Actor in Cardiorenal Syndromes: Mechanisms Involved

Cardiorenal syndrome is a term that defines the complex bidirectional nature of the interaction between cardiac and renal disease. It is well established that patients with kidney disease have higher incidence of cardiovascular comorbidities and that renal dysfunction is a significant threat to the prognosis of patients with cardiac disease. Fibrosis is a common characteristic of organ injury progression that has been proposed not only as a marker but also as an important driver of the pathophysiology of cardiorenal syndromes. Due to the relevance of fibrosis, its study might give insight into the mechanisms and targets that could potentially be modulated to prevent fibrosis development. The aim of this review was to summarize some of the pathophysiological pathways involved in the fibrotic damage seen in cardiorenal syndromes, such as inflammation, oxidative stress and endoplasmic reticulum stress, which are known to be triggers and mediators of fibrosis.

Pre-operative proteinuria, postoperative acute kidney injury and mortality: A systematic review and meta-analysis

OBJECTIVE

To investigate the association of pre-operative proteinuria with postoperative acute kidney injury (AKI) development as well as the requirement for a renal replacement therapy (RRT) and mortality at short-term and long-term follow-up.

BACKGROUND

Postoperative AKI is associated with surgical morbidity and mortality. Pre-operative proteinuria is potentially a risk factor for postoperative AKI and mortality. However, the results in literature are conflicting.

METHODS

We searched PubMed, Embase, Scopus, Web of Science and Cochrane Library from the inception through to 3 June 2020. Observational cohort studies investigating the association of pre-operative proteinuria with postoperative AKI development, requirement for RRT, and all-cause mortality at short-term and long-term follow-up were considered eligible. Using inverse variance method with a random-effects model, the pooled effect estimates and 95% confidence interval (CI) were calculated.

RESULTS

Twenty-eight studies were included. Pre-operative proteinuria was associated with postoperative AKI development [odds ratio (OR) 1.74, 95% CI, 1.45 to 2.09], in-hospital RRT (OR 1.70, 95% CI, 1.25 to 2.32), requirement for RRT at long-term follow-up [hazard ratio (HR) 3.72, 95% CI, 2.03 to 6.82], and long-term all-cause mortality (hazard ratio 1.50, 95% CI, 1.30 to 1.73). In the subgroup analysis, pre-operative proteinuria was associated with increased odds of postoperative AKI in both cardiovascular (OR 1.77, 95% CI, 1.47 to 2.14) and noncardiovascular surgery (OR 1.63, 95% CI, 1.01 to 2.63). Moreover, there is a stepwise increase in OR of postoperative AKI development when the quantity of proteinuria increases from trace to 3+.

CONCLUSION

Pre-operative proteinuria is significantly associated with postoperative AKI and long-term mortality. Pre-operative anaesthetic assessment should take into account the presence of proteinuria to identify high-risk patients.

PROSPERO REGISTRATION

CRD42020190065.

Continuous diffusion spectrum computation for diffusion-weighted magnetic resonance imaging of the kidney tubule system

Background

The use of rigid multi-exponential models (with a priori predefined numbers of components) is common practice for diffusion-weighted MRI (DWI) analysis of the kidney. This approach may not accurately reflect renal microstructure, as the data are forced to conform to the a priori assumptions of simplified models. This work examines the feasibility of less constrained, data-driven non-negative least squares (NNLS) continuum modelling for DWI of the kidney tubule system in simulations that include emulations of pathophysiological conditions.

Methods

Non-linear least squares (LS) fitting was used as reference for the simulations. For performance assessment, a threshold of 5% or 10% for the mean absolute percentage error (MAPE) of NNLS and LS results was used. As ground truth, a tri-exponential model using defined volume fractions and diffusion coefficients for each renal compartment (tubule system: D_tubules , f_tubules ; renal tissue: D_tissue , f_tissue ; renal blood: D_blood , f_blood ;) was applied. The impact of: (I) signal-to-noise ratio (SNR) =40-1,000, (II) number of b-values (n=10-50), (III) diffusion weighting (b-range_small =0-800 up to b-range_large =0-2,180 s/mm²), and (IV) fixation of the diffusion coefficients D_tissue and D_blood was examined. NNLS was evaluated for baseline and pathophysiological conditions, namely increased tubular volume fraction (ITV) and renal fibrosis (10%: grade I, mild) and 30% (grade II, moderate).

Results

NNLS showed the same high degree of reliability as the non-linear LS. MAPE of the tubular volume fraction (f_tubules ) decreased with increasing SNR. Increasing the number of b-values was beneficial for f_tubules precision. Using the b-range_large led to a decrease in MAPE _ftubules compared to b-range_small. The use of a medium b-value range of b=0-1,380 s/mm² improved f_tubules precision, and further b_max increases beyond this range yielded diminishing improvements. Fixing D_blood and D_tissue significantly reduced MAPE _ftubules and provided near perfect distinction between baseline and ITV conditions. Without constraining the number of renal compartments in advance, NNLS was able to detect the (fourth) fibrotic compartment, to differentiate it from the other three diffusion components, and to distinguish between 10% vs. 30% fibrosis.

Conclusions

This work demonstrates the feasibility of NNLS modelling for DWI of the kidney tubule system and shows its potential for examining diffusion compartments associated with renal pathophysiology including ITV fraction and different degrees of fibrosis.

Meta-analysis of AKI to CKD transition in perioperative patients

Background

Recent research shows AKI increases the risk of incident CKD. We hypothesized that perioperative AKI may confer increased risk of subsequent CKD compared to nonperioperative AKI.

Methods

A MEDLINE search was performed for “AKI, CKD, chronic renal insufficiency, surgery, and perioperative” and related terms yielded 5209 articles. One thousand sixty-five relevant studies were reviewed. One thousand six were excluded because they were review, animal, or pediatric studies. Fifty-nine studies underwent full manuscript review by two independent evaluators. Seventeen met all inclusion criteria and underwent analysis. Two-by-two tables were constructed from AKI +/− and CKD +/− data. The R package metafor was employed to determine odds ratio (OR), and a random-effects model was used to calculate weighted ORs. Leave-1-out, funnel analysis, and structured analysis were used to estimate effects of study heterogeneity and bias.

Results

Nonperioperative studies included studies of oncology, percutaneous coronary intervention, and myocardial infarction patients. Perioperative studies comprised patients from cardiac surgery, vascular surgery, and burns. There was significant heterogeneity, but risk of bias was overall assessed as low. The OR for AKI versus non-AKI patients developing CKD in all studies was 4.31 (95% CI 3.01–6.17; p < 0.01). Nonperioperative subjects demonstrated OR 3.32 for developing CKD compared to non-AKI patients (95% CI 2.06–5.34; p < 0.01) while perioperative patients demonstrated OR 5.20 (95% CI 3.12–8.66; p < 0.01) for the same event.

Conclusions

We conclude that studies conducted in perioperative and nonperioperative patient populations suggest similar risk of development of CKD after AKI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00192-6.

Acute kidney injuries induced by thrombotic microangiopathy following severe hemorrhage in puerperants: a case series and literature review

BACKGROUND

Acute kidney injury in puerperants is generally caused by acute tubular necrosis and occasionally by thrombotic microangiopathy (TMA) following post-partum hemorrhage. However, TMA leads to worse clinical outcomes and is rarely reported in the literature. Therefore, this study aimed to evaluate the pathological mechanism behind the development of TMA in puerperants to improve the diagnosis and treatment of this condition.

METHODS

Three patients diagnosed with severe postpartum hemorrhage and TMA from 2014 to 2017 at a nephrology center were retrospectively investigated.

RESULTS

All patients had severe hemorrhage during delivery with a mean blood loss, 4.0 L (range, 2.7-5.0 L). AKI developed rapidly in these patients and was treated with hemodialysis. Following treatment, the mean volume of packed red blood cells was 2.3 L (range, 1.2-3.6 L), and the mean volume of resuscitation fluid was 3.7 L (range, 3.5-4.0 L). All patients had renal biopsy specimens with typical TMA and ATN changes on light microscopy. Two patients required a hysterectomy while another two patients received respiratory support. Only one patient received plasma exchange. None of the patients had recovered normal kidney function by the final follow-up (26-61 months), with two patients having stage 3 chronic kidney disease, and one patient having an end-stage renal disease requiring maintenance hemodialysis.

CONCLUSION

Severe postpartum hemorrhage could lead to TMA, in addition to the common finding of ATN. Renal histology revealed that poor renal outcomes could be attributed to TMA coexisting with ATN. The potential mechanism was ischemia-reperfusion, which was followed by endothelial cell injury and activation of the alternative complement pathway.

Impact of diabetes mellitus on short-term prognosis, length of stay, and costs in patients with acute kidney injury: A nationwide survey in China

Background

International data suggest that people with diabetes mellitus (DM) are at increased risk for worse acute kidney injury (AKI) outcomes; however, the data in China are limited. Therefore, this study aimed to describe the association of DM with short-term prognosis, length of stay, and expenditure in patients with AKI.

Methods

This study was based on the 2013 nationwide survey in China. According to the 2012 Kidney Disease: Improving Global Outcomes (KDIGO) and expanded criteria of AKI, 7604 patients with AKI were identified, and 1404 and 6200 patients were with and without DM, respectively. Clinical characteristics, outcomes, length of stay, and costs of these patients were compared. Multivariate regression analyses were conducted to evaluate the association of DM with mortality, failed renal recovery, length of stay, and costs.

Results

Patients with AKI and DM were older, had higher male preponderance (61.9%), presented with more comorbidities, and had higher serum creatinine levels compared with those without DM. An apparent increase in all-cause in-hospital mortality, length of stay, and costs was found in patients with DM. DM was not independently associated with failed renal recovery (adjusted OR (95%CI): 1.08 (0.94–1.25)) and in-hospital mortality (adjusted OR (95%): 1.16 (0.95–1.41)) in multivariate models. However, the diabetic status was positively associated with the length of stay (β = 0.06, p<0.05) and hospital expenditure (β = 0.10, p<0.01) in hospital after adjusting for possible confounders.

Conclusion

In hospitalized AKI patients, DM (vs. no DM) is independently associated with longer length of stay and greater costs, but is not associated with an increased risk for failed renal recovery and in-hospital mortality.

Monitoring Renal Hemodynamics and Oxygenation by Invasive Probes: Experimental Protocol

Renal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe methods to study control of renal hemodynamics and tissue oxygenation by means of invasive probes in anesthetized rats. Step-by-step protocols are provided for two setups, one for experiments in laboratories for integrative physiology and the other for experiments within small-animal magnetic resonance scanners.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by a separate chapter describing the basic concepts of quantitatively assessing renal perfusion and oxygenation with invasive probes.