The Predictive Value of Cystatin C for AKI in Patients with COVID-19.

Objective. To evaluate a potential of cystatin C blood concentration to predict acute kidney injury (AKI) in patients with severe and extremely severe pneumonia associated with a COVID-19. Materials and methods. An observational prospective study of 117 patients with severe and extremely severe pneumonia associated with a COVID-19 in an ICU setting was conducted in 2020-2022 (site: multifunctional Medical Center, 1586 Military Clinical Hospital of the Ministry of Defense of Russia, Moscow Region, Russia). Routine laboratory tests and instrumental examinations were performed according to generally accepted protocols. Cystatin C concentrations in blood (s-CysC) and urine (u-CysC) were measured by immunoturbidimetric method. Results. AKI was diagnosed in 21 (17.9%) patients, kidney dysfunction without AKI was found in 22 (18.8%) patients with severe and extremely severe pneumonia associated with COVID-19. s-CysC and u-CysC levels in the group of patients with AKI were statistically significantly higher compared to the levels in the group of patients without AKI. The levels of s-CysC obtained within Day 1 - T (-1), and Day 2 - T (-2) prior to AKI onset turned out to be the independent factors for AKI development in patients with severe and extremely severe pneumonia associated with COVID-19: OR 5.37, Wald chi-square 5.534 (CI: 1.324;21.788);P=0.019 and OR 3.225, Wald chi-square 4.121 (CI: 1.041;9.989);P=0.042, respectively. s-CysC T (-2) value is informative, and s- CysC T (-1) is a highly informative predictor of AKI development in severe and extremely severe pneumonia associated with COVID-19: ROC AUC 0.853 (95% CI, 0.74-0.966), P_0.001) with 90% sensitivity and 73% specificity at a cut-off of 1.67 mg/L, and ROC AUC 0.905 (95% CI, 0.837-0.973), P_0.001) with 90% sensitivity and 73% specificity at a cut-off of 1.69 mg/l, respectively. Serum CysC levels started increasing 3 days prior to AKI onset, outpacing the increase of SCr levels. The u-CysC levels were not predictive of AKI development. Impaired renal function probability was increasing with patients' age (P_0.0001). Conclusions. Serum CysC seems to be a statistically significant predictor of AKI. s-CysC levels started increasing 3 days prior to AKI onset, surpassing the increase of SCr levels in patients with severe and extremely severe pneumonia associated with COVID-19. Urine CysC did not achieve statistical significance as a predictor for AKI, although u-CysC concentrations were significantly higher on days 3, 2, 1 prior to AKI onset and on the day of AKI onset in the group of patients with AKI.Copyright © 2023, V.A. Negovsky Research Institute of General Reanimatology. All rights reserved.

Targeting TLR-4 Signaling to Treat COVID-19-induced Acute Kidney Injury

The newly discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has turned into a potentially fatal pandemic illness. Numerous acute kidney injury (AKI) cases have been reported, although diffuse alveolar destruction and acute respiratory failure are the major symptoms of SARS-CoV-2 infection. The AKI, often known as a sudden loss of kidney function, carries a greater risk of mortality and morbidity. AKI was the second most frequent cause of death after acute respiratory distress syndrome (ARDS) in critically ill patients with coronavirus disease 2019 (COVID-19). While most patients with COVID-19 have moderate symptoms, some have severe symptoms, such as septic shock and ARDS. Also, it has been proven that some patients have severe symptoms, such as the failure of several organs. The kidneys are often affected either directly or indirectly. The major signs of kidney involvement are proteinuria and AKI. It is hypothesized that multiple mechanisms contribute to kidney injury in COVID-19. Direct infection of podocytes and proximal tubular cells in the kidneys may lead to acute tubular necrosis and collapsing glomerulopathy. SARS-CoV2 may also trigger a cascade of immunological responses that lead to AKI, including cytokine storm (CS), macrophage activation syndrome, and Toll-like receptor type-4 activation (TLR-4). Other proposed processes of AKI include interactions between organs, endothelial failure, hypercoagulability, rhabdomyolysis, and sepsis.Furthermore, ischemic damage to the kidney might result from the decreased oxygen supply. This article focuses on kidney injury's epidemiology, etiology, and pathophysiological processes. Specifically, it focuses on the CS and the role of TLR-4 in this process. To effectively manage and treat acute kidney damage and AKI in COVID-19, it is crucial to understand the underlying molecular pathways and pathophysiology.

Erratum: Unsupervised clustering reveals phenotypes of AKI in ICU COVID-19 patients.

[This corrects the article DOI: 10.3389/fmed.2022.980160.].

Tocilizumab Associated With Survival in Patients Hospitalized for COVID-19 Acute Respiratory Distress Syndrome and Low Urine Output.

BACKGROUND: Acute respiratory distress syndrome (ARDS) with oliguria is associated with increased mortality. Interleukin-6 (IL-6) plays an integral role in the pathophysiology of both disease processes. Patients who experience severe COVID-19 have demonstrated higher IL-6 levels compared to baseline, and use of tocilizumab has demonstrated efficacy in such cohorts. We set out to investigate the relationship between tocilizumab use, COVID-19 ARDS, low urine output, and mortality. METHODS: Retrospective cohort review of adult patients aged ≥ 18 years with COVID-19 and moderate or severe ARDS, admitted to the intensive care unit (ICU) of a tertiary referral center in metropolitan Detroit. Patients were analyzed based on presence of oliguria (defined as ≤ 0.7 mL/kg/h) on the day of intubation and exposure to tocilizumab while inpatient. The primary outcome was inpatient mortality. RESULTS: One hundred and twenty-eight patients were analyzed, 103 (80%) with low urine output, of whom 30 (29%) received tocilizumab. In patients with low urine output, risk factors associated with mortality on univariate analysis included Black race (P = .028), lower static compliance (P = .015), and tocilizumab administration (P = .002). Tocilizumab (odds ratio 0.245, 95% confidence interval 0.079-0.764, P = .015) was the only risk factor independently associated with survival on multivariate logistic regression analysis. CONCLUSION: In this retrospective cohort review of patients hospitalized with COVID-19 and moderate or severe ARDS, tocilizumab administration was independently associated with survival in patients with low urine output ≤ 0.7 mL/kg/h on the day of intubation. Prospective studies are needed to investigate the impact of urine output on efficacy of interleukin-targeted therapies in the management of ARDS.

Evaluation of Plasma Biomarkers to Predict Major Adverse Kidney Events in Hospitalized Patients With COVID-19.

RATIONALE & OBJECTIVE: Patients hospitalized with COVID-19 are at increased risk for major adverse kidney events (MAKE). We sought to identify plasma biomarkers predictive of MAKE in patients hospitalized with COVID-19. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: A total of 576 patients hospitalized with COVID-19 between March 2020 and January 2021 across 3 academic medical centers. EXPOSURE: Twenty-six plasma biomarkers of injury, inflammation, and repair from first available blood samples collected during hospitalization. OUTCOME: MAKE, defined as KDIGO stage 3 acute kidney injury (AKI), dialysis-requiring AKI, or mortality up to 60 days. ANALYTICAL APPROACH: Cox proportional hazards regression to associate biomarker level with MAKE. We additionally applied the least absolute shrinkage and selection operator (LASSO) and random forest regression for prediction modeling and estimated model discrimination with time-varying C index. RESULTS: The median length of stay for COVID-19 hospitalization was 9 (IQR, 5-16) days. In total, 95 patients (16%) experienced MAKE. Each 1 SD increase in soluble tumor necrosis factor receptor 1 (sTNFR1) and sTNFR2 was significantly associated with an increased risk of MAKE (adjusted HR [AHR], 2.30 [95% CI, 1.86-2.85], and AHR, 2.26 [95% CI, 1.73-2.95], respectively). The C index of sTNFR1 alone was 0.80 (95% CI, 0.78-0.84), and the C index of sTNFR2 was 0.81 (95% CI, 0.77-0.84). LASSO and random forest regression modeling using all biomarkers yielded C indexes of 0.86 (95% CI, 0.83-0.89) and 0.84 (95% CI, 0.78-0.91), respectively. LIMITATIONS: No control group of hospitalized patients without COVID-19. CONCLUSIONS: We found that sTNFR1 and sTNFR2 are independently associated with MAKE in patients hospitalized with COVID-19 and can both also serve as predictors for adverse kidney outcomes. PLAIN-LANGUAGE SUMMARY: Patients hospitalized with COVID-19 are at increased risk for long-term adverse health outcomes, but not all patients suffer long-term kidney dysfunction. Identification of patients with COVID-19 who are at high risk for adverse kidney events may have important implications in terms of nephrology follow-up and patient counseling. In this study, we found that the plasma biomarkers soluble tumor necrosis factor receptor 1 (sTNFR1) and sTNFR2 measured in hospitalized patients with COVID-19 were associated with a greater risk of adverse kidney outcomes. Along with clinical variables previously shown to predict adverse kidney events in patients with COVID-19, both sTNFR1 and sTNFR2 are also strong predictors of adverse kidney outcomes.

Association of Country Income Level With the Characteristics and Outcomes of Critically Ill Patients Hospitalized With Acute Kidney Injury and COVID-19.

Introduction: Acute kidney injury (AKI) has been identified as one of the most common and significant problems in hospitalized patients with COVID-19. However, studies examining the relationship between COVID-19 and AKI in low- and low-middle income countries (LLMIC) are lacking. Given that AKI is known to carry a higher mortality rate in these countries, it is important to understand differences in this population. Methods: This prospective, observational study examines the AKI incidence and characteristics of 32,210 patients with COVID-19 from 49 countries across all income levels who were admitted to an intensive care unit during their hospital stay. Results: Among patients with COVID-19 admitted to the intensive care unit, AKI incidence was highest in patients in LLMIC, followed by patients in upper-middle income countries (UMIC) and high-income countries (HIC) (53%, 38%, and 30%, respectively), whereas dialysis rates were lowest among patients with AKI from LLMIC and highest among those from HIC (27% vs. 45%). Patients with AKI in LLMIC had the largest proportion of community-acquired AKI (CA-AKI) and highest rate of in-hospital death (79% vs. 54% in HIC and 66% in UMIC). The association between AKI, being from LLMIC and in-hospital death persisted even after adjusting for disease severity. Conclusions: AKI is a particularly devastating complication of COVID-19 among patients from poorer nations where the gaps in accessibility and quality of healthcare delivery have a major impact on patient outcomes.

Proton Pump Inhibitors, Kidney Damage, and Mortality: An Updated Narrative Review.

Since their approval by the Food and Drug Administration (FDA) in 1989, proton pump inhibitors (PPIs) have become one of the most highly utilized drugs in the United States, assuming a position as one of the top 10 most prescribed medications in the country. The purpose of PPIs is to limit the amount of gastric acid secreted by the parietal cells via irreversible inhibition of the H+/K+-ATPase pump, therefore maintaining an elevated gastric acid pH of greater than 4 for 15-21 h. Even though PPIs have many clinical uses, they are not without their adverse effects, mimicking achlorhydria. Besides electrolyte abnormalities and vitamin deficiencies, long-term use of PPIs has been linked to acute interstitial nephritis, bone fractures, poor COVID-19 infection outcomes, pneumonia, and possibly an increase in all-cause mortality. The causality between PPI use and increased mortality and disease risk can be questioned since most studies are observational. Confounding variables can greatly affect an observational study and explain the wide-ranging associations with the use of PPIs. Patients on PPIs are generally older, obese, sicker with a higher number of baseline morbidities, and on more medications than the compared PPI non-users. These findings suggest that PPI users are at a higher risk of mortality and complications based on pre-existing conditions. This narrative review aims to update readers on the concerning effects that proton pump inhibitor use can have on patients and give providers a resource to create informed decisions on appropriate PPI use.

Acute Kidney Injury: Medical Causes and Pathogenesis.

Acute kidney injury (AKI) is a common clinical syndrome characterized by a sudden decline in or loss of kidney function. AKI is not only associated with substantial morbidity and mortality but also with increased risk of chronic kidney disease (CKD). AKI is classically defined and staged based on serum creatinine concentration and urine output rates. The etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal. Although this classification may be useful for establishing a differential diagnosis, AKI has mostly multifactorial, and pathophysiologic features that can be divided into different categories. Acute tubular necrosis, caused by either ischemia or nephrotoxicity, is common in the setting of AKI. The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential. In this review, we consider various medical causes of AKI and summarize the most recent updates in the pathogenesis of AKI.

Urine Output and Mortality in Patients Resuscitated from out of Hospital Cardiac Arrest.

BACKGROUND: Limited data exist regarding urine output (UO) as a prognostic marker in out-of-hospital-cardiac-arrest (OHCA) survivors undergoing targeted temperature management (TTM). METHODS: We included 247 comatose adult patients who underwent TTM after OHCA between 2007 and 2017, excluding patients with end-stage renal disease. Three groups were defined based on mean hourly UO during the first 24 h: Group 1 (<0.5 mL/kg/h, n = 73), Group 2 (0.5-1 mL/kg/h, n = 81) and Group 3 (>1 mL/kg/h, n = 93). Serum creatinine was used to classify acute kidney injury (AKI). The primary and secondary outcomes respectively were in-hospital mortality and favorable neurological outcome at hospital discharge (modified Rankin Scale [mRS]<3). RESULTS: In-hospital mortality decreased incrementally as UO increased (adjusted OR 0.9 per 0.1 mL/kg/h higher; p = 0.002). UO < 0.5 mL/kg/h was strongly associated with higher in-hospital mortality (adjusted OR 4.2 [1.6-10.8], p = 0.003) and less favorable neurological outcomes (adjusted OR 0.4 [0.2-0.8], p = 0.007). Even among patients without AKI, lower UO portended higher mortality (40% vs 15% vs 9% for UO groups 1, 2, and 3 respectively, p < 0.001). CONCLUSION: Higher UO is incrementally associated with lower in-hospital mortality and better neurological outcomes. Oliguria may be a more sensitive early prognostic marker than creatinine-based AKI after OHCA.

Acute kidney injury in coronavirus infectious disease: a study of incidence, risk factors, and prognosis during the first wave of the disease in Brazil.

INTRODUCTION: Acute kidney injury (AKI) is one of the main complications of COVID-19 caused by SARS-CoV-2. This study aimed to evaluate the incidence of AKI in Brazilian hospitalized patients diagnosed with COVID-19 and identify the risk factors associated with its onset and those associated with its prognosis. METHODS: A prospective cohort study of hospitalized patients diagnosed with COVID-19 at a public and tertiary university hospital in São Paulo from March to December 2020. RESULTS: There were 347 patients hospitalized with COVID-19, 52.4% were admitted to the intensive care unit (ICU) and 47.6% were admitted to the wards. The overall incidence of AKI was 46.4%, more frequent in the ICU (68.1% vs 22.4, p < 0.01) and the overall mortality was 36.1%. Acute kidney replacement therapy was indicated in 46.6% of patients with AKI. In the general population, the factors associated with AKI were older age (OR 1.03, CI 1-1.05, p < 0.05), mechanical ventilation (OR 1.23, CI 1.06-1.83, p < 0.05), presence of proteinuria (OR 1.46, CI 1.22-1.93, p < 0.05), and use of vasoactive drugs (OR 1.26, CI 1.07-1.92, p < 0.05). Mortality was higher in the elderly (OR 1.08, CI 1.04-1.11, p < 0.05), in those with AKI (OR 1.12, CI 1.02-2.05, p < 0.05), particularly KDIGO stage 3 AKI (OR 1.10, CI 1.22-2.05, p < 0.05) and in need of mechanical ventilation (OR 1.13, CI 1.03-1.60, p < 0.05). CONCLUSION: AKI was frequent in hospitalized patients with COVID-19 and the factors associated with its development were older age, mechanical ventilation, use of vasoactive drugs, and presence of proteinuria, being a risk factor for death.

Epidemiology and Outcomes of AKI Treated With Continuous Kidney Replacement Therapy: The Multicenter CRRTnet Study.

Rationale & Objective: Continuous kidney replacement therapy (CKRT) is the predominant form of acute kidney replacement therapy used for critically ill adult patients with acute kidney injury (AKI). Given the variability in CKRT practice, a contemporary understanding of its epidemiology is necessary to improve care delivery. Study Design: Multicenter, prospective living registry. Setting & Population: 1,106 critically ill adults with AKI requiring CKRT from December 2013 to January 2021 across 5 academic centers and 6 intensive care units. Patients with pre-existing kidney failure and those with coronavirus 2 infection were excluded. Exposure: CKRT for more than 24 hours. Outcomes: Hospital mortality, kidney recovery, and health care resource utilization. Analytical Approach: Data were collected according to preselected timepoints at intensive care unit admission and CKRT initiation and analyzed descriptively. Results: Patients' characteristics, contributors to AKI, and CKRT indications differed among centers. Mean (standard deviation) age was 59.3 (13.9) years, 39.7% of patients were women, and median [IQR] APACHE-II (acute physiologic assessment and chronic health evaluation) score was 30 [25-34]. Overall, 41.1% of patients survived to hospital discharge. Patients that died were older (mean age 61 vs. 56.8, P < 0.001), had greater comorbidity (median Charlson score 3 [1-4] vs. 2 [1-3], P < 0.001), and higher acuity of illness (median APACHE-II score 30 [25-35] vs. 29 [24-33], P = 0.003). The most common condition predisposing to AKI was sepsis (42.6%), and the most common CKRT indications were oliguria/anuria (56.2%) and fluid overload (53.9%). Standardized mortality ratios were similar among centers. Limitations: The generalizability of these results to CKRT practices in nonacademic centers or low-and middle-income countries is limited. Conclusions: In this registry, sepsis was the major contributor to AKI and fluid management was collectively the most common CKRT indication. Significant heterogeneity in patient- and CKRT-specific characteristics was found in current practice. These data highlight the need for establishing benchmarks of CKRT delivery, performance, and patient outcomes. Data from this registry could assist with the design of such studies.

Shortage of iodinated contrast media: Status and possible chances - A systematic review.

PURPOSE: Covid-19 related lockdowns have resulted in a shortage of iodinated contrast media (ICM) in 2022. Health care providers have reacted with implementing conservation strategies to stay operational without compromising patient care. Although articles describing the implemented Interventions have been published, possible chances of the shortage have not yet been mentioned in the literature. METHODS: We conducted a literature search in PubMed and Google Scholar, and analysed the background, interventions, and possible benefits of low-dose ICM regimens. RESULTS: We included 22 articles dealing with "ICM shortage" for the analysis. The delivery bottlenecks in the USA and Australia led to two different countermeasures, 1. reduction of the number of contrast-enhanced image-guided examinations and 2. reduction of the (single) ICM dose. Interventions from both groups have resulted in significant reduction of ICM usage; however, group 1 has contributed more to overall ICM reduction. As benefit of the ICM reduction, we revealed an increased safety for patients at risk (e.g. hypersensitivity reactions, contrast-induced acute kidney injury, thyroid toxic effects). CONCLUSION: The ICM shortage of 2022 has forced health care providers to implement conservation strategies to stay operational. Although there were already proposals for dose reduction before the corona pandemic and the associated supply bottlenecks, this situation led to the use of a reduced amount of contrast agent on a large scale. This presents a good opportunity to reconsider protocols and the use of contrast-enhanced imaging in general for future practice as it offers chances and advantages regarding costs, environmental impact, and patient safety.

The consequences of severe acute respiratory syndrome coronavirus-2 on acute kidney injury among iraqi patients

Background: COVID-19 is considered one of the most infectious diseases that can spread by air droplets and can cause serious complications in the respiratory tract, also could affect many organs like the kidney and causing acute kidney injury (AKI). The study aimed to evaluate the status of the kidney function of patients who are infected with COVID-19 and how the virus is involved in AKI. Methods: The research was conducted from 15 January to 25 February 2021. One hundred patients (56% of males and 44% of females) were involved in the present study. All the samples were tested for COVID-19 using real-time reverse transcription polymerase chain reaction. Kidney function tests such as serum creatinine and blood urea, as well as COVID-19 infection severity measurements such as level of ferritin, D-dimer, and C-reactive protein (CRP) were tested for all patients. Results: All enrolled patients were positive for COVID-19. All the patients (100%) were positive for AKI (the mean of urea and creatinine were 78.87 mg/dl, and 2.16 μg/ml, respectively) and the mean age was 66.9 years. The infection severity was high as the level of ferritin (729.19 ng/ml), D-dimer (3.84 μg/ml), and CRP (71.87 mg/L) were high compared to normal values. The study revealed that AKI is probably worsened by COVID-19 infection, which is also connected to the greater severity of the disease. Conclusion: According to the results, we found a direct link between COVID-19 infection and the development of AKI. The study recommended giving critical care and attention with respect to kidney function to those who had COVID-19 infection. © The Author(s) 2023.

Pediatric Minimal Change Disease and AKI following the Pfizer-BioNTech COVID-19 Vaccine: Causal or incidental correlation?

The global coronavirus 2019 (COVID-19) pandemic required vaccination even in children to reduce infection. We report on the development of acute kidney injury (AKI) and minimal change disease (MCD) nephrotic syndrome (NS), shortly after the first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). A 12-year-old previously healthy boy was referred to our hospital with complaints of peripheral edema and nephrotic range proteinuria. Nine days earlier he had received his first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). Seven days after injection, he developed leg edema, which rapidly progressed to anasarca with significant weight gain. On admission, serum creatinine was 1.3 mg/dL and 24-hour urinary protein excretion was 4 grams with fluid overload. As kidney function continued to decline over the next days, empirical steroid treatment and renal replacement therapy with ultrafiltration were started and kidney biopsy was performed. Seven days after steroid therapy, kidney function began to improve, gradually returning to normal. The association of MCD, nephrotic syndrome and AKI hasn't been previously described following the Pfizer-BioNTech COVID-19 vaccine in pediatric population, but this triad has been reported in adults. We need further similar case reports to establish the real incidence of this possible vaccine side effect. © 2022 Società Italiana di Nefrologia - Anno 39 Volume 6 n° 4.

Urinary liver-type fatty acid binding protein is increased in the early stages of the disease with a risk of acute kidney injury induced by histone.

AIM: Urinary liver-type fatty acid binding protein (L-FABP) has potential utility as an early prognostic biomarker ahead of traditional severity scores in coronavirus disease 2019 and sepsis, however, the mechanism of elevated urinary L-FABP in the disease has not been clearly elucidated. We investigated the background mechanisms of urinary L-FABP excretion through non-clinical animal model focusing on histone, which is one of the aggravating factors in these infectious diseases. METHODS: Male Sprague-Dawley rats were placed in central intravenous catheters, and these rats were given a continuous intravenous infusion of 0.25 or 0.5 mg/kg/min calf thymus histones for 240 min from caudal vena cava. RESULTS: After the administration of histone, urinary L-FABP and gene expression of an oxidative stress marker in the kidney increased in a histone dose-dependent manner before increased serum creatinine. Upon further investigation, fibrin deposition in the glomerulus was observed and it tended to be remarkable in the high dose administrated groups. The levels of coagulation factor were significantly changed after the administration of histone, and these were significantly correlated with the levels of urinary L-FABP. CONCLUSIONS: Firstly, it was suggested that histone is one of the causative agents for the urinary L-FABP increase at an early stage of the disease with a risk of acute kidney injury. Secondly, urinary L-FABP could be a marker reflecting the changes of coagulation system and microthrombus caused by histone in the early stage of acute kidney injury before becoming severely ill and maybe a guide to early treatment initiation.

NAD+ Biosynthesis Impairment and Acute Kidney Injury after Major Vascular Surgery.

Acute kidney injury (AKI) is a serious complication after vascular surgery. Reduced synthesis of nicotinamide adenine dinucleotide (NAD+) from tryptophan is associated with an increased risk of AKI in critically ill patients, patients hospitalized with COVID-19, and cardiac surgery patients, and is marked by elevated urinary quinolinate and quinolinate to tryptophan ratios. We measured quinolinate concentrations in vascular surgery patients to determine if impaired NAD+ synthesis was associated with AKI in this patient population. Eight preoperative and eight postoperative vascular surgery patients who developed AKI were selected from a parent study to participate in this single-center case-control study. They were matched with controls who did not develop AKI based on age, sex, BMI, eGFR, hypertension, and diabetes. Urinary quinolinate and tryptophan concentrations were measured at anesthetic induction and on postoperative day one. Two-sided Mann-Whitney U tests were used to compare quinolinate and quinolinate to tryptophan ratios. Multivariate linear regression modeling was used to estimate the relationship between quinolinate and serum creatinine. There was no difference in preoperative or postoperative urine quinolinate concentrations or the preoperative quinolinate to tryptophan ratio between patients that did and did not develop AKI (p = 0.07, 0.50, and 0.32, respectively). However, postoperative quinolinate to tryptophan ratios were higher in AKI patients (p = 0.04). Further, after adjustment for AKI risk factors, higher preoperative quinolinate concentrations and higher postoperative quinolinate to tryptophan ratios were associated with greater postoperative creatinine increases (p = 0.04 and 0.04, respectively). These data suggest that impaired NAD+ synthesis may contribute to AKI development in vascular surgery patients.

Circulating Soluble Urokinase Plasminogen Activator Receptor as a Predictive Indicator for COVID-19-Associated Acute Kidney Injury and Mortality: Clinical and Bioinformatics Analysis.

Urokinase receptors regulate the interplay between inflammation, immunity, and blood clotting. The soluble urokinase plasminogen activator system is an immunologic regulator affecting endothelial function and its related receptor; the soluble urokinase plasminogen activator receptor (suPAR) has been reported to impact kidney injury. This work aims to measure serum levels of suPAR in COVID-19 patients and correlate the measurements with variable clinicolaboratory parameters and patient outcomes. In this prospective cohort study, 150 COVID-19 patients and 50 controls were included. The circulating suPAR levels were quantified by Enzyme-linked immunosorbent assay (ELISA). Routine COVID-19 laboratory assessments, including CBC, CRP, LDH, serum creatinine, and estimated glomerular filtration rates, were performed. The need for oxygen therapy, CO-RAD score, and survival rates was assessed. Bioinformatic analysis and molecular docking were run to explore the urokinase receptor structure/function and to characterize molecules as potential anti-suPAR therapeutic targets, respectively. We found higher circulating suPAR levels in COVID-19 patients vs. controls (p < 0.001). Circulating suPAR levels positively correlated with COVID-19 severity, the need for O2 therapy, the total leukocytes count, and the neutrophils to lymphocyte ratio, while they were negatively correlated with the O2 saturation level, albumin, blood calcium, lymphocytic count, and GFR. In addition, the suPAR levels were associated with poor prognostic outcomes such as a high incidence of acute kidney injury (AKI) and mortality rate. Kaplan-Meier curves showed a lower survival rate with higher suPAR levels. The logistic regression analysis confirmed the significant association of suPAR levels with the occurrence of AKI related to COVID-19 and with increased mortality probability within three months of COVID-19 follow-up. Some compounds that can act similarly to uPAR were discovered and tested by molecular docking to identify the possible ligand-protein interactions. In conclusion, higher circulating suPAR levels were associated with COVID-19 severity and could be considered a putative predictor of AKI development and mortality.

Renal Thrombotic Microangiopathy: A Review.

Thrombotic microangiopathy (TMA), a pathological lesion observed in a wide spectrum of diseases, is triggered by endothelial injury and/or dysfunction. Although TMA lesions are often accompanied by clinical features of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury, renal-limited forms of TMA are not infrequently encountered in clinical practice. The presence of renal-limited manifestations can be diagnostically challenging, often delaying the initiation of targeted therapy. Prompt investigation and empirical treatment of TMA is warranted to reduce associated morbidity and mortality. Major advances have been made with respect to the pathophysiology of primary TMA entities, with the subsequent development of novel diagnostic tools and lifesaving therapies for diseases like thrombotic thrombocytopenic purpura and complement-mediated TMA. This article will review the clinical presentation and pathologic hallmarks of TMA involving the kidney, and the disease-specific mechanisms that contribute to the endothelial injury that characterizes TMA lesions. Diagnostic approach and both empirical and disease-specific treatment strategies will be discussed, along with the potential role for emerging targeted disease-specific therapies.

Acute kidney injury (AKI) post-mRNA SARS-CoV-2 vaccine in patients with cancer, treated with immune check point inhibitor (ICPi): An immune double whammy!

Background: Immune check point inhibitors (ICPi) have become the first line treatment for most of the cancers and have shown promising results. However, they can provoke reactions, the most feared being immune related adverse events (irAE). Case presentation: We present a series of three cases, of patients recieving ICPi. All three patients developed AKI after administration of SARS-CoV-2 mRNA vaccine. Two patients had kidney-biopsy-proven acute interstitial nephritis (AIN) which responded to ICPi discontinuation and treatment with steroids. One had presumed AIN based on the high levels of CRP and urine retinol binding protein to creatinine ratio and responded to cessation of ICPi alone. Conclusion(s): These three cases demonstrate that a strong immune response from the SARS-CoV-2 mRNA vaccine combined with an uninhibited immune system under influence of ICPi led to an amplification of autoimmunity leading to AKI presenting as AIN.Copyright © The Author(s) 2022.

Predictive Approaches for Acute Dialysis Requirement and Death in COVID-19.

BACKGROUND AND OBJECTIVES: AKI treated with dialysis initiation is a common complication of coronavirus disease 2019 (COVID-19) among hospitalized patients. However, dialysis supplies and personnel are often limited. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using data from adult patients hospitalized with COVID-19 from five hospitals from the Mount Sinai Health System who were admitted between March 10 and December 26, 2020, we developed and validated several models (logistic regression, Least Absolute Shrinkage and Selection Operator (LASSO), random forest, and eXtreme GradientBoosting [XGBoost; with and without imputation]) for predicting treatment with dialysis or death at various time horizons (1, 3, 5, and 7 days) after hospital admission. Patients admitted to the Mount Sinai Hospital were used for internal validation, whereas the other hospitals formed part of the external validation cohort. Features included demographics, comorbidities, and laboratory and vital signs within 12 hours of hospital admission. RESULTS: A total of 6093 patients (2442 in training and 3651 in external validation) were included in the final cohort. Of the different modeling approaches used, XGBoost without imputation had the highest area under the receiver operating characteristic (AUROC) curve on internal validation (range of 0.93-0.98) and area under the precision-recall curve (AUPRC; range of 0.78-0.82) for all time points. XGBoost without imputation also had the highest test parameters on external validation (AUROC range of 0.85-0.87, and AUPRC range of 0.27-0.54) across all time windows. XGBoost without imputation outperformed all models with higher precision and recall (mean difference in AUROC of 0.04; mean difference in AUPRC of 0.15). Features of creatinine, BUN, and red cell distribution width were major drivers of the model's prediction. CONCLUSIONS: An XGBoost model without imputation for prediction of a composite outcome of either death or dialysis in patients positive for COVID-19 had the best performance, as compared with standard and other machine learning models. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_07_09_CJN17311120.mp3.