Avacopan as an additional therapeutic intervention to promote renal recovery in severe ANCA-associated vasculitis: A case report.

Avacopan, a C5a receptor antagonist (C5aR) presents a new therapeutic option to improve outcomes in ANCA-associated vasculitis (AAV). Here we present a case report of a patient initially requiring kidney replacement therapy (KRT), where avacopan was added as an additional adjunctive therapeutic agent late in the treatment course.

Inhibition of pyruvate dehydrogenase kinase 4 ameliorates kidney ischemia-reperfusion injury by reducing succinate accumulation during ischemia and preserving mitochondrial function during reperfusion.

Ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury (AKI), is still without effective therapies. Succinate accumulation during ischemia followed by its oxidation during reperfusion leads to excessive reactive oxygen species (ROS) and severe kidney damage. Consequently, the targeting of succinate accumulation may represent a rational approach to the prevention of IR-induced kidney injury. Since ROS are generated primarily in mitochondria, which are abundant in the proximal tubule of the kidney, we explored the role of pyruvate dehydrogenase kinase 4 (PDK4), a mitochondrial enzyme, in IR-induced kidney injury using proximal tubule cell-specific Pdk4 knockout (Pdk4ptKO) mice. Knockout or pharmacological inhibition of PDK4 ameliorated IR-induced kidney damage. Succinate accumulation during ischemia, which is responsible for mitochondrial ROS production during reperfusion, was reduced by PDK4 inhibition. PDK4 deficiency established conditions prior to ischemia resulting in less succinate accumulation, possibly because of a reduction in electron flow reversal in complex II, which provides electrons for the reduction of fumarate to succinate by succinate dehydrogenase during ischemia. The administration of dimethyl succinate, a cell-permeable form of succinate, attenuated the beneficial effects of PDK4 deficiency, suggesting that the kidney-protective effect is succinate-dependent. Finally, genetic or pharmacological inhibition of PDK4 prevented IR-induced mitochondrial damage in mice and normalized mitochondrial function in an in vitro model of IR injury. Thus, inhibition of PDK4 represents a novel means of preventing IR-induced kidney injury, and involves the inhibition of ROS-induced kidney toxicity through reduction in succinate accumulation and mitochondrial dysfunction.

Animal models of kidney iron overload and ferroptosis: a review of the literature.

In recent years, it has been identified that excess iron contributes to the development of various pathologies and their complications. Kidney diseases do not escape the toxic effects of iron, and ferroptosis is identified as a pathophysiological mechanism that could be a therapeutic target to avoid damage or progression of kidney disease. Ferroptosis is cell death associated with iron-dependent oxidative stress. To study the effects of iron overload (IOL) in the kidney, numerous animal models have been developed. The methodological differences between these models should reflect the IOL-generating mechanisms associated with human IOL diseases. A careful choice of animal model should be considered for translational purposes.

Incidence, predictors, and short-term outcomes of acute kidney injury in children with diabetic ketoacidosis: a systematic review.

BACKGROUND: One-third of children with type 1 diabetes mellitus manifest with diabetic ketoacidosis (DKA). Most children presenting with DKA are in a volume-depleted state, leading to acute kidney injury (AKI). Besides volume depletion, hyperglycemia can induce tubular injury and kidney inflammation. Therefore, a thorough knowledge of incidence of AKI, risk factors, and outcomes in pediatric DKA is desirable to improve its management and outcomes. OBJECTIVE: To synthesize currently available evidence on the incidence, risk factors, and outcomes of AKI in children with DKA. DATA SOURCES: We searched three electronic databases (EMBASE, PubMed, and Web of Science) from inception to September 2022 for original studies reporting AKI in children with DKA. Search strategies for the individual databases were drafted using free text words and MeSH incorporating "acute kidney injury" and "diabetic ketoacidosis." STUDY ELIGIBILITY CRITERIA: Cohort and cross-sectional studies reporting AKI in children with type 1 DM and DKA were included. PARTICIPANTS AND INTERVENTIONS: Children (aged less than 18 years) with type 1 DM and DKA. STUDY APPRAISAL AND SYNTHESIS METHODS: The critical appraisal tool of NHLBI for cohort studies was used to assess the quality of the studies. We estimated the pooled incidence of AKI with 95% CI in children with DKA using a random effects model. The primary outcome was the pooled incidence of AKI during the DKA episodes. RESULTS: Twenty-one studies assessing 4087 children (4500 DKA episodes) reported AKI during DKA episodes. The pooled incidence of any stage of AKI during the DKA episode was 47% (95% CI: 40 to 55). Severe AKI was observed in 28% (21 to 35) of DKA episodes; however, only 4% (1 to 11%) of children with AKI received dialysis. Low serum bicarbonate, low corrected sodium, higher blood sugar, and high blood urea nitrogen at presentation have been reported to be associated with the development of AKI. CONCLUSION: AKI developed in almost half of the DKA episodes, and every fourth DKA episode was associated with severe AKI. The recovery rate from DKA-associated AKI appears to be high; however, further studies are needed to assess the exact impact of AKI on long-term outcomes. REGISTRATION: PROSPERO (CRD42022303200). A higher resolution version of the Graphical abstract is available as Supplementary information.

Association between triglyceride-glucose index and AKI in ICU patients based on MIMICIV database: a cross-sectional study.

BACKGROUND: Methods for early prediction of the occurrence of acute kidney injury (AKI) were limited. The relationship between triglyceride glucose index (TyG) and the incidence of acute kidney injury in ICU patients is unclear. This study aims to explore the relationship between the two. METHODS: Based on their TyG index, participants from the Intensive Care Medical Information Market IV (MIMIC-IV) were divided into quartiles. A logistic regression model was constructed based on the risk of acute kidney injury as the main outcome, in order to detect a potential relationship that may exist between the TyG index and acute kidney injury in ICU patients. Finally, in order to confirm the relationship existing between the TyG index and the results, a restricted cubic spline model was used. RESULTS: In total, 54,263 patients were involved in our present study, of whom 48.2% were male. The occurrence of acute kidney injury was 25.1%. An independent relationship was observed between the TyG index and an increased risk of acute kidney injury through multivariate logistic regression analysis (OR, 1.28 [95% CI 1.22-1.35] p < 0.001). Q4 (5.344-9.911) of the TyG index quartiles was independently associated with an increase in the risk of acute kidney injury (OR, 1.43 [95% CI (1.32-1.54)] p < 0.001). Through the restricted cubic spline regression model, the risk of acute kidney injury was also demonstrated to increase linearly with an increase in the TyG index. CONCLUSION: The triglyceride glucose index is related to the risk of acute kidney injury in ICU patients. In the future, in order to further validate this finding, larger prospective studies are needed.

Anticoagulation practices for continuous renal replacement therapy: a survey of physicians from the United States.

BACKGROUND: During continuous renal replacement therapy (CRRT), anticoagulants are recommended for patients at low risk of bleeding and not already receiving systemic anticoagulants. Current anticoagulants used in CRRT in the US are systemic heparins or regional citrate. To better understand use of anticoagulants for CRRT in the US, we surveyed nephrologists and critical care medicine (CCM) specialists. METHODS: The survey contained 30 questions. Respondents were board certified and worked in intensive care units of academic medical centers or community hospitals. RESULTS: 150 physicians (70 nephrologists and 80 CCM) completed the survey. Mean number of CRRT machines in use increased ∼30% from the pre-pandemic era to 2022. Unfractionated heparin was the most used anticoagulant (43% of estimated patients) followed by citrate (28%). Respondents reported 29% of patients received no anticoagulant. Risk of hypocalcemia (52%) and citrate safety (42%) were the predominant reasons given for using no anticoagulant instead of citrate in heparin-intolerant patients. 84% said filter clogging was a problem when no anticoagulant was used, and almost 25% said increased transfusions were necessary. Respondents using heparin (n = 131) considered it inexpensive and easily obtainable, although of moderate safety, citing concerns of heparin-induced thrombocytopenia and bleeding. Anticoagulant citrate dextrose solution was the most used citrate. Respondents estimated that 37% of patients receiving citrate develop hypocalcemia and 17% citrate lock. CONCLUSIONS: Given the increased use of CRRT and the lack of approved, safe, and effective anticoagulant choices for CRRT in the US, effective use of current and other anticoagulant options needs to be evaluated.

Renal safety and survival among acutely ill hospitalized patients treated by blockers of the Renin-Angiotensin axis or loop diuretics: a single-center retrospective analysis.

BACKGROUND: Concern exists regarding the renal safety of blocking the renin-angiotensin system (RAS) during acute illness, especially in the presence of volume depletion and hemodynamic instability. METHODS: We explored the impact of loop diuretics and RAS blockers on the likelihood of developing acute kidney injury (AKI) or acute kidney functional recovery (AKR) among inpatients. Adjusted odds ratio for AKI, AKR and mortality was calculated, using logistic regression models, with subgroup analysis for patients with estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m2, corrected for blood pressure measurements. RESULTS: 53,289 patients were included. RAS blockade was associated with reduced adjusted odds ratio for both AKI (0.76, CI 0.70-0.83) AKR (0.55, 0.52-0.58), and mortality within 30 days (0.44, 0.41-0.48), whereas loop diuretics were associated with increased risk of AKI (3.75, 3.42-4.12) and mortality (1.71, 1.58-1.85) and reduced AKR (0.71, 0.66-0.75). Comparable impact of RAS blockers and loop diuretics on renal outcomes and death was found among 6,069 patients with eGFR < 30 ml/min/1.73m2. RAS inhibition and diuretics tended to increase the adjusted odds ratios for AKI and to reduce the likelihood of AKR in hypotensive patients. CONCLUSIONS: Reduced blood pressure, RAS blockers and diuretics affect the odds of developing AKI or AKR among inpatients, suggesting possible disruption in renal functional reserve (RFR). As long as blood pressure is maintained, RAS inhibition seems to be safe and renoprotective in this population, irrespective of kidney function upon admission, and is associated with reduced mortality.

Kidney xenotransplantation: Future clinical reality or science fiction?

There is a global shortage of organs for transplantation and despite many governments making significant changes to their organ donation systems, there are not enough kidneys available to meet the demand. This has led scientists and clinicians to explore alternative means of meeting this organ shortfall. One of the alternatives to human organ transplantation is xenotransplantation, which is the transplantation of organs, tissues, or cells between different species. The resurgence of interest in xenotransplantation and recent scientific breakthroughs suggest that genetically engineered pigs may soon present a realistic alternative as sources of kidneys for clinical transplantation. It is therefore important for healthcare professionals to understand what is involved in xenotransplantation and its future implications for their clinical practices. First, we explore the insufficiency of different organ donation systems to meet the kidney shortage. Second, we provide a background and a summary of the progress made so far in xenotransplantation research. Third, we discuss some of the scientific, technological, ethical, and public health issues associated with xenotransplantation. Finally, we summarize the literature on the attitudes of healthcare professionals toward xenotransplantation.

A fair exchange: why living kidney donors in England should be financially compensated.

Every year, hundreds of patients in England die whilst waiting for a kidney transplant, and this is evidence that the current system of altruistic-based donation is not sufficient to address the shortage of kidneys available for transplant. To address this problem, we propose a monopsony system whereby kidney donors can opt-in to receive financial compensation, whilst still preserving the right of individuals to donate without receiving any compensation. A monopsony system describes a market structure where there is only one 'buyer'-in this case the National Health Service. By doing so, several hundred lives could be saved each year in England, wait times for a kidney transplant could be significantly reduced, and it would lessen the burden on dialysis services. Furthermore, compensation would help alleviate the common disincentives to living kidney donation, such as its potential associated health and psychological costs, and it would also help to increase awareness of living kidney donation. The proposed system would also result in significant cost savings that could then be redirected towards preventing kidney disease and reducing health disparities. While concerns about exploitation, coercion, and the 'crowding out' of altruistic donors exist, we believe that careful implementation can mitigate these issues. Therefore, we recommend piloting financial compensation for living kidney donors at a transplant centre in England.

Acute kidney injury associated with piperacillin-tazobactam versus other antibiotics combined with vancomycin in critically ill patients: A retrospective cohort study.

Introduction: Evidence of acute kidney injury (AKI) induced by piperacillin-tazobactam (Piptazo) versus other broad-spectrum antibiotics (BSA) combined with vancomycin has been established in the literature. However, there is limited evidence regarding these combinations among critically ill patients. This study assessed the risk of nephrotoxicity of Piptazo versus other BSA as an add-on to vancomycin among patients admitted to an intensive care unit (ICU). Methods: We have reviewed patients' charts retrospectively to investigate AKI incidence among ICU patients receiving Piptazo versus other BSA as an add-on to vancomycin. Furthermore, we have assessed the duration of AKI and ICU stay, as well as the association between patients' criteria and risk of AKI using logistic regression analyses. Results: A total of 79 patients were included, 50 patients received the Piptazo combination while 29 patients received other BSA combinations. Almost 52 % of the patients in the Piptazo group developed AKI while only 37.9 % of those in the BSA group did, yet the difference was not statistically significant (p = 0.22). On the other hand, the risk of AKI was highly associated with vancomycin trough concentration above 20 mcg/mL, nephrotoxic medications, and African descent (OR 7.1, 95 %CI 1.96-25.84, OR 3.94, 95 %CI 1.27-12.2, OR 3.53, 95 %CI 1.1-11.27, respectively). Conclusion: Although the difference in AKI risk was not statistically significant between Piptazo versus BSA groups, the elevated trough concentration of vancomycin and the concomitant use of nephrotoxic medications, were found to increase the risk of AKI, independently of the combined antibiotics used.

Characterization of temporospatial distribution of renal tubular casts by nephron tracking after ischemia-reperfusion injury.

Renal tubular casts originating from detached epithelial cells after ischemia-reperfusion injury (IRI) can obstruct tubules and negatively impact glomerular filtration rate. Using multiphoton imaging of 400-µm-thick kidney sections, the distribution of casts and morphometric measurement of tubules was performed along the entire nephron for the first time. Tubular nuclei are shed before cell detachment, and visually occlusive casts (grade 3) appeared at 12 h after IRI at the S3/thin descending limb (tDL) junction. Grade 3 casts peaked at 24 h after injury [present in 99% of S3, 78% of tDL, 76% of thin ascending limb (tAL), 60% of medullary thick ascending limb (mTAL), and 10% of connecting tubule segments]. Cast formation in the S3 correlated with selective loss of cell numbers from this tubule segment. By day 3, most mTALs and connecting tubules were cast free, whereas 72% of S3 tubules and 58% of tDLs still contained grade 3 casts. Although bulk phagocytosis of cast material by surviving tubular cells was not observed, mass spectrometry identified large numbers of tryptic peptides in the outer medulla, and trypsin levels were significantly increased in the kidney and urine 24 h after IRI. Administration of either antipain or camostat to inhibit trypsin extended cast burden to the S2, led to sustained accumulation of S3 casts after IRI, but did not affect cast burden in the mTAL or renal function. Our data provide detailed and dynamic mapping of tubular cast formation and resolution after IRI that can inform future interventions to accelerate cast clearance and renal recovery.NEW & NOTEWORTHY This detailed characterization of the dynamic distribution of dead cell debris in ischemically injured kidney tubules reveals which cells in the kidney are most severely injured, when and where tubular casts form, and when (and to a lesser extent, how) they are cleared.

Association Between Deceased Donor Acute Kidney Injury Assessed Using Baseline Serum Creatinine Back-Estimation and Graft Survival: Results From the French National CRISTAL Registry.

RATIONALE & OBJECTIVE: Deceased donor acute kidney injury (AKI) frequently leads to kidney discards, but its impact on long-term graft survival in kidney transplant recipients remains unclear. We investigated the association between deceased donor AKI assessed using back-estimation of baseline serum creatinine (Scr) and graft survival. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: Adult patients represented within the French CRISTAL registry who received a single kidney allograft from brain-dead deceased donors between January 2006 and December 2017. EXPOSURE: A back-estimated Scr baseline value was derived for an assumed glomerular filtration rate at 75mL/min/1.73m2, using the MDRD Study equation. A refined classification system for donor AKI was implemented as follows: no AKI, undetermined AKI/chronic kidney disease (CKD), recovery from AKI, and ongoing AKI. OUTCOME: Death-censored graft survival. ANALYTICAL APPROACH: Multivariable Cox models using a robust variance estimator for paired kidneys from the same donor. RESULTS: We classified 26,786 recipients as follows: no AKI (n=19,276); undetermined AKI/CKD (n=1,745); recovery from AKI (n=2,392); and ongoing AKI (n=3,373). We observed 4,458 kidney graft losses during a median follow-up period of 5.7 years. Compared with no AKI, ongoing AKI was associated with an increased risk of graft failure (hazard ratio [HR], 1.24 [95% CI, 1.13-1.35]). The HRs for graft failure in the undetermined AKI/CKD and recovery from AKI groups (1.22 [95% CI, 1.07-1.38] and 1.18 [95% CI, 1.06-1.31], respectively) were similar to those observed in the ongoing AKI group. The adverse effect of deceased donor AKI was no longer evident when relying either on the admission or the lowest Scr throughout the procurement procedure as baseline Scr. LIMITATIONS: No measurement of urine output in donors. CONCLUSIONS: Deceased donor ongoing AKI, undetermined AKI/CKD, and recovery from AKI according to back-estimated baseline Scr are associated with decreased graft survival. The definition of baseline Scr as the first value measured on admission would have led to a misclassification bias and erroneous estimates.

Early diagnosis of kidney injury in a paediatric population: a prospective cohort study (E-DRIP STUDY).

BACKGROUND: Renal Angina Index (RAI) is a bedside tool for risk stratification of patients to predict acute kidney injury (AKI). Kidney biomarkers are better indicators of real-time injury and give us lead time for diagnosing impending AKI. METHODS: We enrolled consecutive children aged 2 months-14 years admitted to a tertiary hospital in northern India over 2 years. RAI was calculated on day 0 (D0) and urinary (u) and plasma (p) neutrophil gelatinase-associated lipocalin (NGAL) were measured within 6 h of admission. Children were followed for the development of severe AKI on day 3 (D3) using Kidney Disease Improving Global Outcomes criteria to define and stage AKI. RESULTS: Of the 253 children enrolled and analysed, 44 (17.4%) developed D3-AKI (stage 1 in 52.2%, stage 2 in 20.5% and stage 3 in 27.3%). Renal angina (RAI ≥ 8) on D0 was present in 66.7% children who developed stage 2/3 D3-AKI vs. 43.5% in children who did not develop D3-AKI /stage 1 AKI (p = 0.065). Area under ROC (AUROC) curve for D0-RAI to predict D3-severe-AKI was 0.66 (95% CI, 0.55-0.77). AUROC curve for uNGAL and pNGAL to predict D3-severe-AKI was 0.62 (95% CI, 0.50-0.74) and 0.48 (95% CI, 0.35-0.61), respectively. The severe AKI group had greater requirement of ventilation and inotropic support with mortality being thrice higher compared to the non-AKI group. CONCLUSION: RAI ≥ 8 and uNGAL had a high negative predictive value but low sensitivity for predicting D3-severe-AKI. pNGAL had a poor predictive value for D3-severe-AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Artificial intelligence for the prediction of acute kidney injury during the perioperative period: systematic review and Meta-analysis of diagnostic test accuracy.

BACKGROUND: Acute kidney injury (AKI) is independently associated with morbidity and mortality in a wide range of surgical settings. Nowadays, with the increasing use of electronic health records (EHR), advances in patient information retrieval, and cost reduction in clinical informatics, artificial intelligence is increasingly being used to improve early recognition and management for perioperative AKI. However, there is no quantitative synthesis of the performance of these methods. We conducted this systematic review and meta-analysis to estimate the sensitivity and specificity of artificial intelligence for the prediction of acute kidney injury during the perioperative period. METHODS: Pubmed, Embase, and Cochrane Library were searched to 2nd October 2021. Studies presenting diagnostic performance of artificial intelligence in the early detection of perioperative acute kidney injury were included. True positives, false positives, true negatives and false negatives were pooled to collate specificity and sensitivity with 95% CIs and results were portrayed in forest plots. The risk of bias of eligible studies was assessed using the PROBAST tool. RESULTS: Nineteen studies involving 304,076 patients were included. Quantitative random-effects meta-analysis using the Rutter and Gatsonis hierarchical summary receiver operating characteristics (HSROC) model revealed pooled sensitivity, specificity, and diagnostic odds ratio of 0.77 (95% CI: 0.73 to 0.81),0.75 (95% CI: 0.71 to 0.80), and 10.7 (95% CI 8.5 to 13.5), respectively. Threshold effect was found to be the only source of heterogeneity, and there was no evidence of publication bias. CONCLUSIONS: Our review demonstrates the promising performance of artificial intelligence for early prediction of perioperative AKI. The limitations of lacking external validation performance and being conducted only at a single center should be overcome. TRIAL REGISTRATION: This study was not registered with PROSPERO.

[Overlooked compartment syndrome of the hand after burn injury and known polytoxicomania]. / Übersehenes Kompartmentsyndrom an der Hand nach Brandverletzung und bekannter Polytoxikomanie.

A young man suffered the fatal combination of burn injuries and acute kidney failure caused by substantial rhabdomyolysis after lying on the floor in a somnolent condition for 12 h. This symptom constellation should always make physicians aware of a potential compartment syndrome.

Acute kidney injury adversely affects the clinical course of acute myeloid leukemia patients undergoing induction chemotherapy.

Acute kidney injury (AKI) complicates the clinical course of hospitalized patients by increasing need for intensive care treatment and mortality. There is only little data about its impact on AML patients undergoing intensive induction chemotherapy. In this study, we analyzed the incidence as well as risk factors for AKI development and its impact on the clinical course of AML patients undergoing induction chemotherapy. We retrospectively analyzed data from 401 AML patients undergoing induction chemotherapy between 2007 and 2019. AKI was defined and stratified according to KIDGO criteria by referring to a defined baseline serum creatinine measured on day 1 of induction chemotherapy. Seventy-two of 401 (18%) AML patients suffered from AKI during induction chemotherapy. AML patients with AKI had more days with fever (7 vs. 5, p = 0.028) and were more often treated on intensive care unit (45.8% vs. 10.6%, p < 0.001). AML patients with AKI had a significantly lower complete remission rate after induction chemotherapy and, with 402 days, a significantly shorter median overall survival (OS) (median OS for AML patients without AKI not reached). In this study, we demonstrate that the KIDGO classification allows mortality risk stratification for AML patients undergoing induction chemotherapy. Relatively mild AKI episodes have impact on the clinical course of these patients and can lead to chronic impairment of kidney function. Therefore, we recommend incorporating risk factors for AKI in decision-making considering nutrition, fluid management, as well as the choice of potentially nephrotoxic medication in order to decrease the incidence of AKI.

Renal functional recovery among inpatients: A plausible marker of reduced renal functional reserve.

Renal functional reserve (RFR) reflects the ability of the kidney to enhance glomerular filtration rate (GFR) in response to a protein load. Chronic kidney disease (CKD) leads to diminished RFR, since the capacity for whole-body GFR to increase through hyperfiltration of remaining nephrons is limited. Evaluating 41,456 inpatients following computerised tomography we reported many exhibiting acute kidney injury (AKI) but more patients with recovering kidney function (AKR), presumably reflecting resolution of their critical conditions. The incidences of AKI and AKR were closely co-associated and were both inversely correlated with baseline kidney function. We discuss this phenomenon, arguing that AKR among inpatients with an acute illness, like AKI, may often reflect underlying subtle CKD with diminished RFR.

An Integrated Review of the Hepatorenal Syndrome.

Among the complications of cirrhosis, hepatorenal syndrome (HRS) is characterized by having the worst survival rate. HRS is a disorder that involves the deterioration of kidney function caused primarily by a systemic circulatory dysfunction, but in recent years, systemic inflammation and cirrhotic cardiomyopathy have been discovered to also play an important role. The diagnosis of HRS requires to meet the new International Club of Ascites-Acute Kidney Injury (ICA-AKI) and Hepatorenal Syndrome-Acute Kidney Injury (HRS-AKI) criteria after ruling out other causes of kidney injury. At the time of diagnosis, it is important to start the medical treatment as soon as possible where three types of vasoconstrictors have been recognized: vasopressin analogs (ornipressin and terlipressin), alpha-adrenergic agonists (norepinephrine and midodrine) and somatostatin analogues (octreotide); all should be combined with albumin infusion. Among them, terlipressin and albumin are the first lines of treatment in most cases, although terlipressin should be monitor closely due to its adverse events. The best treatment of choice is a liver transplant, because it is the only definitive treatment for this disease.

Renal Involvement and Early Prognosis in Patients with COVID-19 Pneumonia.

BACKGROUND: Some patients with COVID-19 pneumonia also present with kidney injury, and autopsy findings of patients who died from the illness sometimes show renal damage. However, little is known about the clinical characteristics of kidney-related complications, including hematuria, proteinuria, and AKI. METHODS: In this retrospective, single-center study in China, we analyzed data from electronic medical records of 333 hospitalized patients with COVID-19 pneumonia, including information about clinical, laboratory, radiologic, and other characteristics, as well as information about renal outcomes. RESULTS: We found that 251 of the 333 patients (75.4%) had abnormal urine dipstick tests or AKI. Of 198 patients with renal involvement for the median duration of 12 days, 118 (59.6%) experienced remission of pneumonia during this period, and 111 of 162 (68.5%) patients experienced remission of proteinuria. Among 35 patients who developed AKI (with AKI identified by criteria expanded somewhat beyond the 2012 Kidney Disease: Improving Global Outcomes definition), 16 (45.7%) experienced complete recovery of kidney function. We suspect that most AKI cases were intrinsic AKI. Patients with renal involvement had higher overall mortality compared with those without renal involvement (28 of 251 [11.2%] versus one of 82 [1.2%], respectively). Stepwise multivariate binary logistic regression analyses showed that severity of pneumonia was the risk factor most commonly associated with lower odds of proteinuric or hematuric remission and recovery from AKI. CONCLUSIONS: Renal abnormalities occurred in the majority of patients with COVID-19 pneumonia. Although proteinuria, hematuria, and AKI often resolved in such patients within 3 weeks after the onset of symptoms, renal complications in COVID-19 were associated with higher mortality.

Ultrastructural Evidence for Direct Renal Infection with SARS-CoV-2.

BACKGROUND: A significant fraction of patients with coronavirus disease 2019 (COVID-19) display abnormalities in renal function. Retrospective studies of patients hospitalized with COVID-19 in Wuhan, China, report an incidence of 3%-7% progressing to ARF, a marker of poor prognosis. The cause of the renal failure in COVID-19 is unknown, but one hypothesized mechanism is direct renal infection by the causative virus, SARS-CoV-2. METHODS: We performed an autopsy on a single patient who died of COVID-19 after open repair of an aortic dissection, complicated by hypoxic respiratory failure and oliguric renal failure. We used light and electron microscopy to examine renal tissue for evidence of SARS-CoV-2 within renal cells. RESULTS: Light microscopy of proximal tubules showed geographic isometric vacuolization, corresponding to a focus of tubules with abundant intracellular viral arrays. Individual viruses averaged 76 µm in diameter and had an envelope studded with crown-like, electron-dense spikes. Vacuoles contained double-membrane vesicles suggestive of partially assembled virus. CONCLUSIONS: The presence of viral particles in the renal tubular epithelium that were morphologically identical to SARS-CoV-2, and with viral arrays and other features of virus assembly, provide evidence of a productive direct infection of the kidney by SARS-CoV-2. This finding offers confirmatory evidence that direct renal infection occurs in the setting of AKI in COVID-19. However, the frequency and clinical significance of direct infection in COVID-19 is unclear. Tubular isometric vacuolization observed with light microscopy, which correlates with double-membrane vesicles containing vacuoles observed with electronic microscopy, may be a useful histologic marker for active SARS-CoV-2 infection in kidney biopsy or autopsy specimens.