Acute kidney injury-an overview of diagnostic methods and clinical management

Decadal Analysis of Age-Adjusted Mortality Rates for Acute and Chronic Kidney Disease in Brazil, 2000-2021

Introduction Renal failure, comprising acute kidney injury (AKI) and chronic kidney disease (CKD), involves a decline or loss of kidney function. AKI is sudden and reversible, with a rapid decline in function over hours to days, while CKD involves persistent abnormalities lasting at least three months. Developing countries are seeing a rise in AKI cases, especially in critically ill patients. Globally, there's a growing occurrence and mortality rate linked to CKD. Methods The study used a retrospective cross-sectional design to analyze AKI and CKD mortality rates in Brazil from 2019 to 2022. Data on population and demographics, including sex and age, were obtained from the Brazilian Institute of Geography and Statistics. Mortality data for kidney diseases were sourced from the Brazilian Hospital Information System. The analysis utilized the Joinpoint Regression Program to calculate average annual percentage changes (AAPCs) and their respective 95% confidence intervals. Weighted Bayesian information criterion was used to determine the significance levels and identify the best-fitting combination of line segments and joinpoints. Results The study findings revealed a significant rise in AKI mortality rates for both males and females, from 2008 to 2021 (APC = 3.16; CI: 2.29 to 5.93), with higher mortality rates recorded among males compared to women over the entire study period. Analyses according to age groups showed that males between the ages 40 to 49 experienced the most rapid increase in mortality during the 2019 - 2021 period (APC = 35.41; CI: 16.72 to 46.57); meanwhile, the most rapid increase in mortality for females was observed from 2019 to 2021, and this was among those aged 30 to 39 (APC = 40.33; CI = 6.48 to 59.78). Furthermore, there was an observable upward trend in mortality related to CKD (APC = 0.70; CI: 0.41 to 1.01), with males consistently having higher mortality rates throughout the entire study period. The elderly population, both males and females, experienced the most rapid increase in CKD-related mortality, with AAPC values of 2.32 (CI: 1.82 to 2.89) for males and 1.62 (CI: 1.08 to 2.10) for females. Conclusion We observed a consistent increase in mortality rates from acute kidney diseases for both males and females since 2008, with males experiencing higher mortality rates overall. The study highlighted the need for further research to understand the underlying factors contributing to these trends. Additionally, interventions targeting modifiable risk factors and improving access to healthcare could help reduce mortality related to renal failure.

Development and validation of a race-agnostic computable phenotype for kidney health in adult hospitalized patients

Standard race adjustments for estimating glomerular filtration rate (GFR) and reference creatinine can yield a lower acute kidney injury (AKI) and chronic kidney disease (CKD) prevalence among African American patients than non-race adjusted estimates. We developed two race-agnostic computable phenotypes that assess kidney health among 139,152 subjects admitted to the University of Florida Health between 1/2012-8/2019 by removing the race modifier from the estimated GFR and estimated creatinine formula used by the race-adjusted algorithm (race-agnostic algorithm 1) and by utilizing 2021 CKD-EPI refit without race formula (race-agnostic algorithm 2) for calculations of the estimated GFR and estimated creatinine. We compared results using these algorithms to the race-adjusted algorithm in African American patients. Using clinical adjudication, we validated race-agnostic computable phenotypes developed for preadmission CKD and AKI presence on 300 cases. Race adjustment reclassified 2,113 (8%) to no CKD and 7,901 (29%) to a less severe CKD stage compared to race-agnostic algorithm 1 and reclassified 1,208 (5%) to no CKD and 4,606 (18%) to a less severe CKD stage compared to race-agnostic algorithm 2. Of 12,451 AKI encounters based on race-agnostic algorithm 1, race adjustment reclassified 591 to No AKI and 305 to a less severe AKI stage. Of 12,251 AKI encounters based on race-agnostic algorithm 2, race adjustment reclassified 382 to No AKI and 196 (1.6%) to a less severe AKI stage. The phenotyping algorithm based on refit without race formula performed well in identifying patients with CKD and AKI with a sensitivity of 100% (95% confidence interval [CI] 97%-100%) and 99% (95% CI 97%-100%) and a specificity of 88% (95% CI 82%-93%) and 98% (95% CI 93%-100%), respectively. Race-agnostic algorithms identified substantial proportions of additional patients with CKD and AKI compared to race-adjusted algorithm in African American patients. The phenotyping algorithm is promising in identifying patients with kidney disease and improving clinical decision-making.

Melatonin Reduces Aggravation of Renal Ischemia-Reperfusion Injury in Obese Rats by Maintaining Mitochondrial Homeostasis and Integrity through AMPK/PGC-1α/SIRT3/SOD2 Activation

This study examined the potential benefits of melatonin against renal ischemia and reperfusion (IR) injury in obesity and explored the underlying mechanisms. Obesity was induced in Wistar rats by feeding a high-fat diet for 16 weeks. Three obese groups that underwent renal IR induction (30-min renal ischemia followed by 24-h reperfusion) were randomly assigned to receive melatonin at ischemic onset, reperfusion onset, or pretreatment for 4 weeks before IR induction. Groups of vehicle-treated obese and normal-diet-fed rats that underwent sham or IR induction were also included in the study. The results showed that renal functional and structural impairments after IR incidence were aggravated in obese rats compared to normal-diet-fed rats. The obese-IR rats also exhibited oxidative stress, mitochondrial dysfunction, apoptosis, and mitochondrial dynamics and mitophagy imbalances, which were all considerably improved upon melatonin treatment, irrespective of the treatment time. This study suggests the prophylactic and therapeutic efficacy of melatonin in IR-induced acute kidney injury (AKI) in obese individuals, which may improve the prognosis of AKI in these populations. The benefits of melatonin are likely mediated by the modification of various signaling molecules within the mitochondria that maintain mitochondrial redox balance and lead to the protection of mitochondrial homeostasis and integrity.

Evaluation of the Efficiency of TIMP-2 as a Biomarker for Acute Kidney Injury in Sepsis

The aim of this study was to evaluate the biomarker potential of TIMP-2 in septic-induced acute kidney injury (AKI). Healthy male rats (n=56, age 8-10 weeks, body weight 250-300 g) were randomized into 3 groups: controls (intact rats, n=6), sham-operated (SO, n=24), and sepsis model (cecum ligation and perforation, CLP, n=24). Thirty minutes before and 6, 12, 24, and 48 h after surgery, blood samples were collected to measure serum creatinine, blood urea nitrogen (BUN), and TIMP-2 and the kidneys were isolated for histopathological analysis and Western blotting. The key sepsis-related genes were screened through bioinformatics analysis. In 24 and 48 h after surgery, 2 rats in the SO group reached the diagnostic criteria of AKI (increased levels of serum creatinine and BUN). In the CLP group, serum creatinine in 6 h after the surgery was slightly higher than 30 min before the surgery, but this change did not meet the diagnostic criteria for AKI. In the CLP group, BUN was normal 6 h after the surgery, but increased after 12 h. In more than 50% rats of the CLP group, serum creatinine and BUN significantly increased 12 h after operation, so this can be diagnosed as AKI. In rats of the CLP group, plasma TIMP-2 was elevated 6 h after surgery and increased with time, suggesting that plasma TIMP-2 can be used as an early marker of AKI. Histological examination of the kidneys in this group revealed destruction of the renal tubular structure, swelling of renal tubular epithelium, the disappearance of brush edge and collapse of necrotic epithelial cells, etc., and the degree of damage increased with time. Immunohistochemistry showed that TIMP-2 was expressed in rats of the CLP group at all terms of the experiment. The expression of TIMP-2 and pyroptosis-related proteins (NLRP3, IL-1β, caspase-1, and GSDMD) in the CLP group was higher than in the SO group (p<0.05) and increased with time, suggesting that pyroptosis is involved in AKI. Thus, plasma TIMP-2 is sensitive indicator for the early detection of kidney injury and can be used as an early biomarker of AKI.

Effects of statins on the incidence and outcomes of acute kidney injury in critically ill patients: a systematic review and meta-analysis

Introduction

In critically ill patients, acute kidney injury (AKI) is a common complication with very high mortality rates. Several studies indicated that statin therapy, primarily due to its so-called pleiotropic effects, may beneficially affect the course of the disease, otherwise leading to significant clinical complications. However, both the original research as well as available meta-analyses on these associations report equivocal results. This leaves open a question whether pre- and perioperative statins might prevent AKI and improve overall prognosis in patients undergoing surgery.

Material and methods

Following a systematic search of the literature, we performed a meta-analysis of selected clinical studies investigating the impact of statin treatment on the development and the clinical outcomes of AKI among subjects undergoing surgeries. The pooled odds ratios (OR) with 95% confidence intervals (CI) for the development of AKI and AKI-associated mortality, as well as the pooled mean differences (MD) and 95% CI for mean intensive care unit (ICU) stay and overall hospital length of stay were calculated for statin users compared to non-users.

Results

Our results showed a highly significant association between statin use and the decrease in mortality of patients with AKI (OR = 0.73, 95% CI: 0.69-0.77; p<0.001). The development of AKI (OR = 0.92, 95% CI: 0.63-1.33; p = 0.659) as well as the ICU stay (MD = -0.02, 95% CI: -0.06 - 0.02; p = 0.321) were not significantly affected, while the overall hospital length of stay (MD = -0.49, 95% CI: -0.91 -0.07; p = 0.020) was reduced. Subgroup analysis showed that both pre- and postoperative statin use were not associated with the risk of AKI.

Conclusions

Our analysis showed a significant association between statin therapy and overall mortality of critically ill surgical patients diagnosed with AKI, while at the same time the use of statins did not affect the length of their stay in ICU.

Machine Learning for Acute Kidney Injury Prediction in the Intensive Care Unit

Machine learning is the field of artificial intelligence in which computers are trained to make predictions or to identify patterns in data through complex mathematical algorithms. It has great potential in critical care to predict outcomes, such as acute kidney injury, and can be used for prognosis and to suggest management strategies. Machine learning can also be used as a research tool to advance our clinical and biochemical understanding of acute kidney injury. In this review, we introduce basic concepts in machine learning and review recent research in each of these domains.

Daily Hemodialysis Helps Critical Nephritic Lupus Patient: A Case Report

Background: Nephritic lupus is the most common and serious complication of systemic lupus erythematosus (SLE) and is associated with a worse prognosis. Hemodialysis is effective in alleviating symptoms and renal involvement in a nephritic lupus patient. Method: A 33-year-old female was diagnosed with SLE in September 2017. She was also diagnosed with diffuse membranous proliferative glomerulonephritis, as confirmed with a kidney biopsy. She complained of gradual onset limb weakness and peripheral edema 3 months before admission. She was treated with 6 cycles of cyclophosphamide and continued with methylprednisolone 16 mg once daily, hydroxychloroquine 200 mg once daily, and myfortic 360 mg twice daily. A day before ICU admission, her creatinine level was increased to 4.6 mg/dl with an estimated GFR of 12 ml/min and her symptoms then worsened into seizures and lung edema. Daily hemodialysis with heparin-free SLEDD was performed. About 2L was extracted for the first 6 hours with Qb 150 ml and Qd 300 ml and was continued until the day after. For the next 4 days, 3L was extracted per day with Qb 200ml and Qd 500 ml. The patients’ hemodynamic status was within normal limits during dialysis period. The condition improved and the patient was transferred to the ward. Discussions: Hemodialysis is a way to solve kidney problems in in nephritic lupus and SLE patients in general. It should not only be employed for mainly kidney problems but could be beneficial in autoimmune patients with conditions such as nephritic lupus. Slowly extracted dialysis type would be a good and inexpensive option to resolve nephritic lupus in compromising lupus patients. Filtration is ensured and solute removal is achieved relatively equivalent to CRRT. Conclusion: Daily hemodialysis could increase renal salvation by providing less creatinine serum and removing accumulated fluids. The SLEDD type could be used for critical nephritic lupus patients with reduced hemodynamic perturbations, minimal anticoagulant, and lower cost.

Nucleic Acid Nanotechnology for Diagnostics and Therapeutics in Acute Kidney Injury

Acute kidney injury (AKI) has impacted a heavy burden on global healthcare system with a high morbidity and mortality in both hospitalized and critically ill patients. However, there are still some shortcomings in clinical approaches for the disease to date, appealing for an earlier recognition and specific intervention to improve long-term outcomes. In the past decades, owing to the predictable base-pairing rule and highly modifiable characteristics, nucleic acids have already become significant biomaterials for nanostructure and nanodevice fabrication, which is known as nucleic acid nanotechnology. In particular, its excellent programmability and biocompatibility have further promoted its intersection with medical challenges. Lately, there have been an influx of research connecting nucleic acid nanotechnology with the clinical needs for renal diseases, especially AKI. In this review, we begin with the diagnostics of AKI based on nucleic acid nanotechnology with a highlight on aptamer- and probe-functionalized detection. Then, recently developed nanoscale nucleic acid therapeutics towards AKI will be fully elucidated. Furthermore, the strengths and limitations will be summarized, envisioning a wiser and wider application of nucleic acid nanotechnology in the future of AKI.

Nouvelles approches diagnostiques de l’insuffisance rénale aiguë

L’insuffisance rénale, véritable problème de santé publique, concernerait plus de 82 000 personnes en France. On estime que 5 à 10 % de la population française souffriraient d’une maladie rénale pouvant conduire à une insuffisance rénale avec un taux de mortalité de plus de 10 % par an. À l’inverse de la maladie rénale chronique irréversible, l’insuffisance rénale aiguë est considérée comme un dysfonctionnement transitoire et réversible. Au-delà de l’intérêt de la prévention, le diagnostic précoce de l’insuffisance rénale aiguë permettrait de mettre en place des thérapeutiques adaptées et ciblées afin d’éviter l’évolution vers des lésions rénales irréversibles. Cependant, il demeure un véritable challenge pour le praticien puisque l’on présume que près de 10 % de la population française présenteraient des lésions rénales asymptomatiques. Bien que la définition de l’insuffisance rénale aiguë ait été simplifiée durant ces dernières années, il existe de nombreuses limites. En parallèle, des progrès majeurs ont été réalisés notamment en termes de diagnostic. L’objectif de cette mise au point est de faire un rappel sur l’évolution de l’insuffisance rénale aiguë, les définitions actuelles et de présenter les nouvelles approches diagnostiques en cours de développement.

Development and Provisional Validation of a Multiplex LC-MRM-MS Test for Timely Kidney Injury Detection in Urine

Kidney injury is a complication frequently encountered in hospitalized patients. Early detection of kidney injury prior to loss of renal function is an unmet clinical need that should be targeted by a protein-based biomarker panel. In this study, we aim to quantitate urinary kidney injury biomarkers at the picomolar to nanomolar level by liquid chromatography coupled to tandem mass spectrometry in multiple reaction monitoring mode (LC-MRM-MS). Proteins were immunocaptured from urinary samples, denatured, reduced, alkylated, and digested into peptides before LC-MRM-MS analysis. Stable-isotope-labeled peptides functioned as internal standards, and biomarker concentrations were attained by an external calibration strategy. The method was evaluated for selectivity, carryover, matrix effects, linearity, and imprecision. The LC-MRM-MS method enabled the quantitation of KIM-1, NGAL, TIMP2, IGFBP7, CXCL9, nephrin, and SLC22A2 and the detection of TGF-β1, cubilin, and uromodulin. Two to three peptides were included per protein, and three transitions were monitored per peptide for analytical selectivity. The analytical carryover was <1%, and minimal urine matrix effects were observed by combining immunocapture and targeted LC-MRM-MS analysis. The average total CV of all quantifier peptides was 26%. The linear measurement range was determined per measurand and found to be 0.05–30 nmol/L. The targeted MS-based method enables the multiplex quantitation of low-abundance urinary kidney injury biomarkers for future clinical evaluation.

Development of antibiotic resistance in periprosthetic joint infection after total knee arthroplasty

AIMS

The management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is challenging. The correct antibiotic management remains elusive due to differences in epidemiology and resistance between countries, and reports in the literature. Before the efficacy of surgical treatment is investigated, it is crucial to analyze the bacterial strains causing PJI, especially for patients in whom no organisms are grown.

METHODS

A review of all revision TKAs which were undertaken between 2006 and 2018 in a tertiary referral centre was performed, including all those meeting the consensus criteria for PJI, in which organisms were identified. Using a cluster analysis, three chronological time periods were created. We then evaluated the antibiotic resistance of the identified bacteria between these three clusters and the effectiveness of our antibiotic regime.

RESULTS

We identified 129 PJIs with 161 culture identified bacteria in 97 patients. Coagulase-negative staphylococci (CNS) were identified in 46.6% cultures, followed by Staphylococcus aureus in 19.8%. The overall resistance to antibiotics did not increase significantly during the study period (p = 0.454). However, CNS resistance to teicoplanin (p < 0.001), fosfomycin (p = 0.016), and tetracycline (p = 0.014) increased significantly. Vancomycin had an 84.4% overall sensitivity and 100% CNS sensitivity and was the most effective agent.

CONCLUSION

Although we were unable to show an overall increase in antibiotic resistance in organisms that cause PJI after TKA during the study period, this was not true for CNS. It is concerning that resistance of CNS to new antibiotics, but not vancomycin, has increased in a little more than a decade. Our findings suggest that referral centres should continuously monitor their bacteriological analyses, as these have significant implications for prophylactic treatment in both primary arthroplasty and revision arthroplasty for PJI. Cite this article: Bone Joint J 2021;103-B(6 Supple A):171-176.

A role of connexin 43 on the drug-induced liver, kidney, and gastrointestinal tract toxicity with associated signaling pathways

Drug-induced organ toxicity/injury, especially in the liver, kidney, and gastrointestinal tract, is a systematic disorder that causes oxidative stress formation and inflammation resulting in cell death and organ failure. Current therapies target reactive oxygen species (ROS) scavenging and inhibit inflammatory factors in organ injury to restore the functions and temporary relief. Organ cell function and tissue homeostasis are maintained through gap junction intercellular communication, regulating connexin hemichannels. Mis-regulation of such connexin, especially connexin (Cx) 43, affects a comprehensive process, including cell differentiation, inflammation, and cell death. Aim to describe knowledge about the importance of connexin role and insights therapeutic targeting. Cx43 misregulation has been implicated in recent decades in various diseases. Moreover, in recent years there is increasing evidence that Cx43 is involved in the toxicity process, including hepatic, renal, and gastrointestinal disorders. Cx43 has the potential to initiate the immune system to cause cell death, which has been activated in the acceleration of apoptosis, necroptosis, and autophagy signaling pathway. So far, therapies targeting Cx43 have been under inspection and are subjected to clinical trial phases. This review elucidates the role of Cx43 in drug-induced vital organ injury, and recent reports compromise its function in the major signaling pathways.

Emerging medical therapies in crush syndrome - progress report from basic sciences and potential future avenues

Crush injury is a disease that is commonly found in victims of earthquakes, debris flows, mine disasters, explosions, terrorist attacks, local wars, and other accidents. The complications that arise due to the crush injury inflicted on victims give rise to crush syndrome (CS). If not treated in time, the mortality rate of CS is very high. The most important measure that can be taken to reduce mortality in such situations is to immediately start treatment. However, the traditional treatment methods such as fluid resuscitation, diuresis, and hemodialysis are not feasible enough to be carried out at the disaster scene. So there is a need for developing new treatments that are efficient and convenient. Because it is difficult to diagnose in the disaster area and reach the treatment equipment and treat on time. It has become a new research needs to be directed into identifying new medical treatment targets and methods using the etiology and pathophysiological mechanisms of CS. In recent years, a large number of new anti-oxidant and anti-inflammatory drug therapies have been shown to be highly efficacious in CS rat/mouse models. Some of them are expected to become specific drugs for the emergency treatment of a large number of patients who may develop CS in the aftermath of earthquakes, wars, and other disasters in the future. Hence, we have reviewed the latest research on the medical therapy of CS as a source for anyone wishing to pursue research in this direction.

Immunopathology of Acute Kidney Injury in Severe Malaria

Acute kidney injury (AKI) is a common feature of severe malaria, and an independent risk factor for death. Previous research has suggested that an overactivation of the host inflammatory response is at least partly involved in mediating the kidney damage observed in P. falciparum patients with AKI, however the exact pathophysiology of AKI in severe malaria remains unknown. The purpose of this mini-review is to describe how different aspects of malaria pathology, including parasite sequestration, microvascular obstruction and extensive intravascular hemolysis, may interact with each other and contribute to the development of AKI in severe malaria, by amplifying the damaging effects of the host inflammatory response. Here, we highlight the importance of considering how the systemic effects and multi-organ involvement of malaria are intertwined with the localized effects on the kidney.

Medical history risk factors in primary progressive multiple sclerosis: A case-control study

Background: The association between medical history and primary progressive multiple sclerosis (PPMS) development has not been well documented in the pertinent literature. The possible association between 23 medical diseases and PPMS occurrence was assessed in the present study. Methods: In order to figure out the possible association between several medical histories and PPMS occurrence, the present population-based case-control study examined 143 PPMS cases in Tehran, Iran, from 2019 to 2020. Diagnosis of PPMS was confirmed by neurologists based on the 2017 McDonald criteria. Sex-matched healthy controls (n = 143) were selected using the random-digit dialing (RDD) technique. Face-to-face and telephone interviews were conducted for gathering the data. The conditional logistic regression model was used to calculate adjusted and unadjusted odds ratio (OR) at a 95% confidence interval (CI). Results: A significant association was found between PPMS development and diseases like depression (OR = 3.12, 95% CI: 1.49-6.53), migraine (OR = 0.19, 95% CI: 0.05-0.67), infectious mononucleosis (OR = 13.16, 95% CI: 2.74-63.17), hypothyroidism (OR = 3.20, 95% CI: 1.23-8.30), and kidney failure (OR = 3.76, 95% CI: 1.41-9.99). Conclusion: Lifetime history of depression, infectious mononucleosis, hypothyroidism, and kidney failure might increase the risk of PPMS development, while individuals with positive history of migraine disease are at lower risk for developing PPMS.

Comparison of risk of acute kidney injury between patients receiving the combination of teicoplanin and piperacillin/tazobactam versus vancomycin and piperacillin/tazobactam

BACKGROUND/PURPOSE

To compare the risk of acute kidney injury (AKI) among patients receiving teicoplanin (TA) plus piperacillin/tazobactam (TZP) versus vancomycin (VAN) plus TZP.

METHODS

This was a retrospective cohort study using electronic health records. Patients were included if a combination of glycopeptide and TZP or other selected β-lactams were used during hospitalization. In the main analysis, two study groups were identified: TA + TZP and VAN + TZP. We used 1:1 propensity score matching to control for potential confounders, and hazard ratio (HR) of AKI between study groups was calculated. We further compared the risk of AKI between patients receiving VAN + TZP and VAN + β-lactams as an auxiliary analysis to verify the validity of the study design.

RESULTS

The final sample contained 211 pairs of patients receiving either TA + TZP or VAN + TZP. The median dosage of TA and VAN were 10.3 and 26.7 mg/kg/day, respectively. The median trough level of VAN was 12.3 mg/L. The AKI risk in the TA + TZP group was similar to that in the VAN + TZP group (12.3% vs. 11.4%; HR = 1.25 [0.72-2.18], p = 0.44). The auxiliary analysis showed a higher risk of AKI in the VAN + TZP group than in the VAN + β-lactam group (13.2% vs. 9.6%; HR = 1.63 [1.04-2.55], p = 0.03).

CONCLUSION

Our study results showed that the risk of AKI were similar for patients receiving TA + TZP and VAN + TZP. However, low VAN and high TA dose may play a role in this finding. Further investigation on the association between AKI and TA + TZP is required.

Rational selection of a biomarker panel targeting unmet clinical needs in kidney injury

The pipeline of biomarker translation from bench to bedside is challenging and limited biomarkers have been adopted to routine clinical care. Ideally, biomarker research and development should be driven by unmet clinical needs in health care. To guide researchers, clinical chemists and clinicians in their biomarker research, the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has developed a structured questionnaire in which the clinical gaps in current clinical pathways are identified and desirable performance specifications are predefined. In kidney injury, the high prevalence of the syndrome acute kidney injury (AKI) in the hospital setting has a significant impact on morbidity, patient survival and health care costs, but the use of biomarkers indicating early kidney injury in daily patient care remains limited. Routinely, medical labs measure serum creatinine, which is a functional biomarker, insensitive for detecting early kidney damage and cannot distinguish between renal and prerenal AKI. The perceived unmet clinical needs in kidney injury were identified through the EFLM questionnaire. Nephrologists within our tertiary care hospital emphasized that biomarkers are needed for (1) early diagnosis of in-hospital AKI after a medical insult and in critically ill patients, (2) risk stratification for kidney injury prior to a scheduled (elective) intervention, (3) kidney injury monitoring in patients scheduled to receive nephrotoxic medication and after kidney transplantation and (4) differentiation between prerenal AKI and structural kidney damage. The biomarker search and selection strategy resulted in a rational selection of an eleven-protein urinary panel for kidney injury that target these clinical needs. To assess the clinical utility of the proposed biomarker panel in kidney injury, a multiplexed LC-MS test is now in development for the intended translational research.

Ischemia-Reperfusion Injury Reduces Kidney Folate Transporter Expression and Plasma Folate Levels

Acute or chronic kidney disease can cause micronutrient deficiency. Patients with end-stage renal disease, kidney transplantation or on dialysis have reduced circulating levels of folate, an essential B vitamin. However, the molecular mechanism is not well understood. Reabsorption of folate in renal proximal tubules through folate transporters is an important process to prevent urinary loss of folate. The present study investigated the impact of acute kidney injury (AKI) on folate transporter expression and the underlying mechanism. AKI was induced in Sprague-Dawley rats that were subjected to kidney ischemia (45 min)-reperfusion (24 h). Both male and female rats displayed kidney injury and low plasma folate levels compared with sham-operated rats. The plasma folate levels were inversely correlated to plasma creatinine levels. There was a significant increase in neutrophil gelatinase-associated lipocalin (NGAL) and IL-6 mRNA expression in the kidneys of rats with ischemia-reperfusion, indicating kidney injury and increased inflammatory cytokine expression. Ischemia-reperfusion decreased mRNA and protein expression of folate transporters including folate receptor 1 (FOLR1) and reduced folate carrier (RFC); and inhibited transcription factor Sp1/DNA binding activity in the kidneys. Simulated ischemia-reperfusion through hypoxia-reoxygenation or Sp1 siRNA transfection in human proximal tubular cells inhibited folate transporter expression and reduced intracellular folate levels. These results suggest that ischemia-reperfusion injury downregulates renal folate transporter expression and decreases folate uptake by tubular cells, which may contribute to low folate status in AKI. In conclusion, ischemia-reperfusion injury can downregulate Sp1 mediated-folate transporter expression in tubular cells, which may reduce folate reabsorption and lead to low folate status.

Acute kidney injury is associated with severe infection and fatality in patients with COVID-19: A systematic review and meta-analysis of 40 studies and 24,527 patients

Currently, coronavirus disease 2019 (COVID-19) is spreading rapidly around the world. This study aimed to investigate whether the presence of acute kidney injury (AKI) might increase the risk of severe infection and fatality in COVID-19 patients. We searched the PubMed, Web of Science, ScienceDirect, MedRxiv and COVID-19 academic research communication platforms for studies reporting severe infection rates and case-fatality rates in COVID-19 patients with and without AKI up to June 20, 2020. The main outcomes were the comparisons of the severe infection rates and fatality rates in COVID-19 patients with and without AKI and the estimation of the odds ratio (OR) and its 95 % confidence interval (CI) for severe infection and mortality. Statistical analyses were performed with R statistical software. A total of 40 studies involving 24,527 patients with COVID-19 were included in our meta-analysis. The incidence of AKI was 10 % (95 % CI 8%-13 %) in COVID-19 patients. The patients had higher severe infection and fatality rates (55.6 % vs. 17.7 % and 63.1 % vs. 12.9 %, respectively, all P < 0.01) with COVID-19. AKI was a predictor of fatality (OR = 14.63, 95 % CI: 9.94-21.51, P < 0.00001) and severe infection (OR = 8.11, 95 % CI: 5.01-13.13, P < 0.00001) in patients with COVID-19. Higher levels of serum creatinine (Scr) and blood urea nitrogen (BUN) were associated with a significant increase in fatality [Scr: mean difference (MD): 20.19 μmol/L, 95 % CI: 14.96-25.42, P < 0.001; BUN: MD: 4.07 mmol/L, 95 % CI: 3.33-4.81, P < 0.001] and severe infection (Scr: MD: 7.78 μmol/L, 95 % CI: 4.43-11.14, P < 0.00001, BUN: MD: 2.12 mmol/L, 95 % CI: 1.74-2.50, P < 0.00001) in COVID-19 patients. In conclusion, AKI is associated with severe infection and higher fatality rates in patients with COVID-19. Clinicians should pay more attention to the monitoring and treatment of COVID-19 patients with AKI.

Importance of sodium-glucose cotransporter 2 inhibitor use in diabetic patients with acute heart failure

BACKGROUND

It is known that once heart failure occurs in older patients with diabetes, the overall prognosis is extremely poor. We investigated whether early initiation of SGLT2 inhibitor therapy after admission was beneficial for diabetic patients requiring inpatient treatment for acute heart failure.

METHODS

We retrospectively assessed consecutive patients with comorbid diabetes who were admitted to the Department of Cardiology in Tosei General Hospital for treatment of acute heart failure. Patients were divided into two groups: those who initiated SGLT2 inhibitor therapy (SGLT2 inhibitor group; mean age: 73 ± 9 years) and those who did not receive the inhibitors during hospitalization (conventional treatment group; mean age: 75 ± 10 years).

RESULTS

No intergroup differences were observed in the distribution of either the severity or classes of heart failure on admission. Glycosylated hemoglobin levels were significantly higher in the SGLT2 inhibitor group (HbA1c: 8.1% ± 0.8%) than in the conventional treatment group (HbA1c: 7.1% ± 0.8%) (p = 0.003). After admission, patients in both groups recovered equally well, and in almost the same period of time, before discharge. The rate of diuretics use at the time of discharge in the SGLT2 inhibitor group (n = 8, 67%) was significantly lower than that in the conventional treatment group (n = 19, 100%) (p = 0.016). In particular, the dose of loop diuretics in the conventional treatment group was 34 ± 4 mg/day while that in the SGLT2 inhibitor group was significantly lower at 13 ± 5 mg/day (p = 0.008). During hospitalization, the incidence of acute kidney injury was significantly higher in the conventional treatment group (n = 11, 58%) than in the SGLT2 inhibitor group (n = 2, 16%) (p = 0.031).

CONCLUSIONS

For the treatment and management of heart failure in patients with diabetes, early initiation of SGLT2 inhibitor therapy appears to be effective.

Translational Safety Biomarkers of Kidney Injury

Acute kidney injury continues to be a common problem and there continues to be a medical need for sensitive translational biomarkers for clinical monitoring. The past decade has yielded unprecedented progress in fundamental research into novel kidney biomarker evaluation and the mechanistic understanding of kidney injury; as such, these novel biomarkers increasingly are being used in preclinical drug development and in early clinical trials of drug candidates on a case-by-case basis, as well as in medical and veterinary practice. With the recent successful clinical qualification of a subset of novel accessible biomarker candidates for use in early phase clinical trials, continued clinical evaluation may enable expanded regulatory qualification for more generalized clinical use. This review provides a comprehensive overview about the discovery and development of kidney safety biomarkers with a focus on current progress in nonclinical research, progress toward translation to the clinic, and perspectives on future opportunities.

Protective effect of the ethanolic and methanolic leaf extracts of Madhuca longifolia against diclofenac-induced toxicity in female Wistar albino rats

BACKGROUND

Diclofenac is commonly prescribed Non-Steroidal Anti-Inflammatory Drug (NSAIDs) as it has anti-inflammatory, analgesic and anti-pyretic properties. Long term usage and over-dosage of diclofenac is associated with adverse effects like drug-induced liver injury, gastrointestinal and renal toxicity. The therapeutic uses of medicinal plants have gained a prominent role in recent years. Madhuca longifolia is a tree found throughout India, which is known to have several pharmacological activities. The aim of our study is to investigate the potential effect of the ethanolic and methanolic leaf extracts of M. longifolia against diclofenac-induced toxicity.

METHODS

The rats used for the experiment were divided into seven groups. Group-1 was the normal control. Group-2 was administered with diclofenac (50 mg/kg b.w./day/ip) on the 4th and the 5th day. Group-3 was treated with diclofenac and ELEML (500 mg/kg b.w./day/po) on all 5 days. Group-4 was treated with diclofenac and MLEML (500 mg/kg b.w./day/po) on all 5 days. Standard drug silymarin (25 mg/kg b.w./day/po) was given to the rats of group-5 along with diclofenac. Group-6 and group-7 were treated with ethanolic leaf extract and methanolic leaf extract of M. longifolia respectively. After the study period, the rats were evaluated for parameters like liver and renal markers, antioxidants and histopathological changes.

RESULTS

This study has proved the beneficial effect of ethanolic and methanolic leaf extract of M. longifolia against diclofenac-induced toxicity wherein ethanolic leaf extract showed a better result than methanolic leaf extract.

CONCLUSION

Our study has concluded the beneficial effect of ethanolic and methonolic leaf extract of Madhuca longifolia against DFC-induced toxicity. This study proves that it has potential effect on hepato, renal and gastro toxicity in female Wistar albino rats. It can further be studied to understand its mechanism in treating toxicity.

Protective effect of hyperoside against renal ischemia-reperfusion injury via modulating mitochondrial fission, oxidative stress, and apoptosis

Ischemia/reperfusion (IR) is a common cause of acute kidney injury (AKI). However, effective therapies for IR-induced AKI are lacking. Hyperoside is an active constituent in the flowers of Abelmoschus manihot (L.) Medic, which is a traditional Chinese herbal medicine for the treatment of various ischemic brain and heart diseases. Our previous study demonstrated that hyperoside inhibited adriamycin induced podocyte injury both in vivo and in vitro. The aim of this study is to investigate the effect of hyperoside in IR-induced AKI. In mice, pretreatment of hyperoside could markedly attenuate IR-induced AKI, tubular cell apoptosis, and oxidative stress in the kidneys. Meanwhile, we found hyperoside inhibited IR-induced mitochondrial fission by suppressing OMA1 mediated proteolysis of optic atrophy 1 (OPA1). Consistently, in human proximal tubular epithelial cells, hyperoside might inhibit CoCl₂-induced mitochondrial fission, oxidative stress, and apoptosis by regulating OMA1-OPA1 axis. Taken together, our results support the idea that OMA1-OPA1 mediated mitochondrial fission can be used for the prevention of AKI. Hyperoside might have novel therapeutic potential in the treatment of AKI.

Emergency Department Management of Acute Kidney Injury, Electrolyte Abnormalities, and Renal Replacement Therapy in the Critically Ill

Acute kidney injury (AKI) is a common sequela of critical illness. Clinical manifestation of AKI varies and can include electrolyte abnormalities, anion gap, or non-anion-gap metabolic acidosis. Treatment strategies require careful identification of the cause of the AKI, relying on both clinical history and laboratory data. Once the cause has been identified, treatment can then target the underlying cause and avoid further insults. Conservative management should first be attempted for patients with AKI. If conservative management fails, renal replacement therapy or hemodialysis can be used.

Renoprotective effect of remote ischemic postconditioning in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background

Whether upper arm remote ischemic postconditioning (RIPostC) exerts protection to kidney in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) remains unknown.

Methods

Sixty-four patients with STEMI were randomized to PPCI + RIPostC (n=29) and PPCI (n=35) groups. RIPostC consisting of 4 cycles of 5 minutes occlusion/reperfusion by cuff inflation/deflation of the upper arm was started within 1 minute after the first balloon dilatation. Peripheral venous blood samples were collected before PPCI and at 0.5, 8, 24, 48, and 72 hours after PPCI to detect serum creatinine (SCr) and creatine kinase-MB (CK-MB). Acute kidney injury (AKI) rate and estimated glomerular filtration rate (eGFR) were calculated. The transthoracic echocardiography was performed 7 days after PPCI to assess left ventricular ejection fraction (LVEF).

Results

The patients in the PPCI + RIPostC group had a lower AKI rate compared with those in the PPCI group (P=0.04). The eGFR after PPCI increased in the PPCI + RIPostC group compared to the PPCI group (P<0.01). The peak of CK-MB concentration in the PPCI + RIPostC group was significantly lower than that in the PPCI group (P<0.01). The area under the curve of CK-MB decreased in the PPCI + RIPostC group compared with that in the PPCI group. LVEF in the PPCI + RIPostC group was significantly higher than that in the PPCI group (P=0.04).

Conclusion

Upper arm RIPostC exerts renal and cardiac protection following cardiac ischemia–reperfusion in patients with STEMI.

Real-Time and Non-invasive Monitoring of the Activation of the IRE1α-XBP1 Pathway in Individuals with Hemodynamic Impairment

Many stressors that are encountered upon kidney injury are likely to trigger endoplasmic reticulum (ER) stress, subsequently activating transcriptional, translational and metabolic reprogramming. Monitoring early cellular adaptive responses engaged after hemodynamic impairment yields may represent a clinically relevant approach. However, a non-invasive method for detecting the ER stress response has not been developed. We combined a metabolomic approach with genetic marker analyses using urine from individuals undergoing scheduled cardiac surgery under cardiopulmonary bypass to investigate the feasibility and significance of monitoring the ER stress response in the kidney. We developed an original method based on fragment analysis that measures urinary levels of the spliced X-box binding protein 1 (sXBP1) mRNA as a proxy of inositol-requiring enzyme 1α (IRE1α) activity because sXBP1 is absolutely sensitive and specific for ER stress. The early engagement of the ER stress response after ischemic stress is critical for protecting against tissue damage, and individuals who mount a robust adaptive response are protected against AKI. The clinical consequences of our findings are of considerable importance because ER stress is involved in numerous conditions that lead to AKI and chronic kidney disease; in addition, the detection of ER stress is straightforward and immediately available in routine practice.

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Endoplasmic Reticulum (ER) stress is involved in the pathophysiology of numerous kidney diseases.

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We developed a method based on fragment analysis that measures urinary levels of XBP1 mRNA to detect renal ER stress.

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ER stress occurs early after cardiopulmonary bypass, a procedure leading to acute kidney injury.

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The detection of renal ER stress in this context can predict the occurrence of acute kidney injury.

The better care of patients with kidney disease requires the identification of biomarkers of ongoing tissue injury to provide therapies to slow disease progression. In this study, we have developed for the first time a non-invasive (urinary) biomarker of a protective cellular process called Endoplasmic Reticulum stress that occurs early in the kidney after ischemic injury. Renal ischemic injury follows cardiac surgery and could lead to acute kidney injury. Our results indicate that the early detection of individuals who do not activate Endoplasmic Reticulum stress could help to identify individuals who will develop acute kidney injury.