Postmortem Kidney Pathology Findings in Patients with COVID-19

Research on the global trends of COVID-19 associated acute kidney injury: a bibliometric analysis

Critically ill COVID-19 patients may exhibit various clinical symptoms of renal dysfunction including severe Acute Kidney Injury (AKI). Currently, there is a lack of bibliometric analyses on COVID-19-related AKI. The aim of this study is to provide an overview of the current research status and hot topics regarding COVID-19 AKI. The literature was retrieved from the Web of Science Core Collection (WoSCC) database. Subsequently, we utilized Microsoft Excel, VOSviewer, Citespace, and Pajek software to revealed the current research status, emerging topics, and developmental trends pertaining to COVID-19 AKI. This study encompassed a total of 1507 studies on COVID-19 AKI. The United States, China, and Italy emerged as the leading three countries in terms of publication numbers, contributing 498 (33.05%), 229 (15.20%), and 140 (9.29%) studies, respectively. The three most active and influential institutions include Huazhong University of Science and Technology, Wuhan University and Harvard Medical School. Ronco C from Italy, holds the record for the highest number of publications, with a total of 15 papers authored. Cheng YC's work from China has garnered the highest number of citations, totaling 470 citations. The co-occurrence analysis of author keywords reveals that 'mortality', 'intensive care units', 'chronic kidney disease', 'nephrology', 'renal transplantation', 'acute respiratory distress syndrome', and 'risk factors' emerge as the primary areas of focus within the realm of COVID-19 AKI. In summary, this study analyzes the research trends in the field of COVID-19 AKI, providing a reference for further exploration and research on COVID-19 AKI mechanisms and treatment.

The Road to Precision Medicine for Acute Kidney Injury

OBJECTIVES

Acute kidney injury (AKI) is a common form of organ dysfunction in the ICU. AKI is associated with adverse short- and long-term outcomes, including high mortality rates, which have not measurably improved over the past decade. This review summarizes the available literature examining the evidence of the need for precision medicine in AKI in critical illness, highlights the current evidence for heterogeneity in the field of AKI, discusses the progress made in advancing precision in AKI, and provides a roadmap for studying precision-guided care in AKI.

DATA SOURCES

Medical literature regarding topics relevant to precision medicine in AKI, including AKI definitions, epidemiology, and outcomes, novel AKI biomarkers, studies of electronic health records (EHRs), clinical trial design, and observational studies of kidney biopsies in patients with AKI.

STUDY SELECTION

English language observational studies, randomized clinical trials, reviews, professional society recommendations, and guidelines on areas related to precision medicine in AKI.

DATA EXTRACTION

Relevant study results, statements, and guidelines were qualitatively assessed and narratively synthesized.

DATA SYNTHESIS

We synthesized relevant study results, professional society recommendations, and guidelines in this discussion.

CONCLUSIONS

AKI is a syndrome that encompasses a wide range of underlying pathologies, and this heterogeneity has hindered the development of novel therapeutics for AKI. Wide-ranging efforts to improve precision in AKI have included the validation of novel biomarkers of AKI, leveraging EHRs for disease classification, and phenotyping of tubular secretory clearance. Ongoing efforts such as the Kidney Precision Medicine Project, identifying subphenotypes in AKI, and optimizing clinical trials and endpoints all have great promise in advancing precision medicine in AKI.

Complement system is overactivated in patients with IgA nephropathy after COVID-19

IgA nephropathy (IgAN), which has been confirmed as a complement mediated autoimmune disease, is also one form of glomerulonephritis associated with COVID-19. Here, we aim to investigate the clinical and immunological characteristics of patients with IgAN after COVID-19. The level of plasma level of C5a (p < 0.001), soluble C5b-9 (p = 0.018), FHR5 (p < 0.001) were all significantly higher in Group CoV (33 patients with renal biopsy-proven IgAN experienced COVID-19) compared with Group non-CoV (44 patients with IgAN without COVID-19), respectively. Compared with Group non-CoV, the intensity of glomerular C4d (p = 0.017) and MAC deposition (p < 0.001) and Gd-IgA1 deposition (p = 0.005) were much stronger in Group CoV. Our finding revealed that for IgAN after COVID-19, mucosal immune responses to SARS-CoV-2 infection may result in the overactivation of systemic and renal local complement system, and increased glomerular deposition of Gd-IgA1, which may lead to renal dysfunction and promote renal progression in IgAN patients.

The dynamics and outcomes of AKI progression during the COVID-19 pandemic

PURPOSE

Acute kidney injury (AKI) associated with COVID-19 is associated with poor prognosis. This study assessed the hitherto uninvestigated impact of COVID-19 on the progression and clinical outcomes of patients with AKI.

METHODS

Data from 576 patients with AKI admitted between 13/3/20 and 13/5/20 were studied. Increasingly complex analyses, from logistic regressions to competing-risk and multi-state models, have revealed insights into AKI progression dynamics associated with PCR-confirmed COVID-19 acquisition and death. Meta-analyses of case fatality ratios among patients with AKI were also conducted.

RESULTS

The overall case-fatality ratio was 0.33 [95% CI (0.20-0.36)]; higher in COVID-19 positive (COVID+) patients 0.52 [95% CI (0.46-0.58)] than in their negative (COVID-) counterparts 0.16 [95% CI (0.12-0.20)]. In AKI Stage-3 patients, that was 0.71 [95% CI (0.64-0.79)] among COVID+ patients with 45% dead within 14 days and 0.35 [95% CI (0.25-0.44)] in the COVID- group and 28% died within 14 days. Among patients diagnosed with AKI Stage-1 within 24 h, the probability of progression to AKI Stage-3 on day 7 post admission was 0.22 [95% CI (0.17-0.27)] among COVID+ patients, and 0.06 [95% CI (0.03, 0.09)] among those who tested negative. The probability of discharge by day 7 was 0.71 [95% CI (0.66, 0.75)] in COVID- patients, and 0.27 [95% CI (0.21, 0.32)] in COVID+ patients. By day 14, in AKI Stage-3 COVID+ patients, that was 0.35 [95% CI (0.25, 0.44)] with little change by day 10, that is, 0.38 [95% CI (0.29, 0.47)].

CONCLUSION

These results are consistent with either a rapid progression in severity, prolonged hospital care, or high case fatality ratio among AKI Stage-3 patients, significantly exacerbated by COVID-19 infection.

Effect of humidity on postmortem changes in rats

IMPORTANCE

In veterinary forensic science, accurately determining the postmortem interval (PMI) is crucial for identifying the causes of animal deaths. Autolysis, a significant postmortem process, influences PMI estimation, but its relationship with humidity is not well understood.

OBJECTIVE

This study aimed to improve the accuracy of PMI estimates in veterinary forensic cases by looking into how different humidity levels affect autolysis in different organs of rats.

METHODS

The study involved 38 male rats, examining histopathological changes in their heart, liver, and pancreas. These organs were subjected to controlled humidity levels (20%, 55%, and 80%) at a constant 22°C. Tissue samples were collected at several intervals (0 h, 12 h, 24 h, 3 days, and 8 days) for comprehensive analysis.

RESULTS

Distinct autolytic characteristics in animal organs emerged under varying humidity conditions. The low-humidity environment rapidly activated autolysis more than the high-humidity environment. In addition, it was found that lower humidity caused nuclear pyknosis, cytoplasmic disintegration, and myofiber interruption. The liver, in particular, showed portal triad aggregation and hepatocyte individuation. The pancreas experienced cell fragmentation and an enlarged intracellular space. High humidity also caused the loss of striations in cardiac tissues, and the liver showed vacuolation. Under these conditions, the pancreas changed eosinophilic secretory granules.

CONCLUSIONS AND RELEVANCE

The study successfully established a clear connection between the autolytic process in PMIs and relative humidity. These findings are significant for developing a more accurate and predictable method for PMI estimation in the field of veterinary forensic science.

[COVID-19 in the intensive care unit]

The acute respiratory failure as well as ARDS (acute respiratory distress syndrome) have challenged clinicians since the initial description over 50 years ago. Various causes can lead to ARDS and therapeutic approaches for ARDS/ARF are limited to the support or replacement of organ functions and the prevention of therapy-induced consequences. In recent years, triggered by the SARS-CoV-2 pathogen, numerous cases of acute lung failure (C-ARDS) have emerged. The pathophysiological processes of classical ARDS and C-ARDS are essentially similar. In their final stages of inflammation, both lead to a disruption of the blood-air barrier. Treatment strategies for C-ARDS, like classical ARDS, focus on supporting or replacing organ functions and preventing consequential damage. This article summarizes the treatment strategies in the intensive care unit.

Risk of acute kidney injury in critically-ill patients with COVID-19 compared with seasonal influenza: a retrospective cohort study

Background

The SARS-CoV-2 virus can bind to angiotensin-converting enzyme 2 receptors on host renal cells and may cause acute kidney injury (AKI). The comparative risks of AKI in patients severely ill with COVID-19 and influenza A have not been examined.

Methods

This is a retrospective cohort study including patients with positive PCR results for SARS-CoV-2 or influenza A virus admitted to the intensive care units (ICUs) of 15 public hospitals in Hong Kong between 1st January 2013 and 30th April 2023. Patients who were already on chronic dialysis or had missing values in the confounder model were excluded. Data were retrieved from Hong Kong Hospital Authority's electronic healthcare records. The primary outcome was incident AKI during ICU stay. Secondary outcomes included acute kidney disease (AKD) and hospital mortality. All analyses were examined in multivariable regression adjusting for potential confounders (age, sex, baseline eGFR, PaO2/FiO2 ratio, baseline comorbidities, APACHE IV predicted risk of death, Charlson Comorbidity Index, emergent hospital admission, admission from elderly home, reason for ICU admission, presence of bacterial co-infections, use of medications [including vasopressors, antiviral medications, steroids and nephrotoxic antibiotics], as well as anaemia and leucocytosis). Patients were matched in a 1:1 ratio using a propensity score generated based on the full confounder model. The analyses were repeated using inverse probability weighting and in propensity-score matched cohorts.

Findings

A total of 5495 ICU patients were identified. After excluding 1093 (19.9%) patients who met the exclusion criteria and 74 (1.3%) patients who had one or more missing values in the logistic regression model, a total of 4328 patients were included in the final analysis, with 2787 (64.4%) patients who tested positive for SARS-CoV-2 reverse transcription (RT)-PCR and 1541 (35.6%) patients who tested positive for influenza A virus RT-PCR. The comorbidity burden was greater in patients with COVID-19 (Charlson Comorbidity Index 3 [2-4] vs. 3 [1-4]), but the median APACHE IV predicted risk of death was significantly lower (0.19 [0.08-0.38] vs. 0.25 [0.11-0.52]). A total of 1053 (37.8%) patients with COVID-19 and 828 (53.7%) patients with influenza A developed AKI of any stage during ICU stay. In adjusted analysis, the risk of AKI was significantly lower in patients with COVID-19 compared with influenza A (adjusted odds ratio 0.51, 95% confidence interval 0.42-0.61, P < 0.0001]. The risk of stage 3 AKI and AKD were also significantly lower in patients with COVID-19. These results remained robust in multiple pre-planned sensitivity analyses including inverse probability weighting and propensity score matching.

Interpretation

Our results suggest that the risk of AKI in patients severely ill with COVID-19 was lower than in patients with influenza A. The burden of concurrent organ failure complicating respiratory viral infections, such as the higher disease-attributable risk of AKI associated with influenza, should be clarified.

Funding

An unrestricted philanthropic donation from Mr and Mrs Laurence Tse, The Wai Im Charitable Foundation, Chan Sui Kau Family Benefits and Charitable Foundation, So Ka Wing and Lee Sau Ying Charitable Foundation, Mr & Mrs Tam Wing Fun Edmund Renal Research Fund, the Theme-Based Research Scheme of the Research Grants Council, Hong Kong Special Administrative Region, The Government of the Hong Kong Special Administrative Region; Programme of Enhancing Laboratory Surveillance and Investigation of Emerging Infectious Diseases and Antimicrobial Resistance for the Department of Health of the Hong Kong Special Administrative Region Government; Emergency COVID-19 Project, Major Projects on Public Security, National Key Research and Development Program; Emergency Collaborative Project of Guangzhou Laboratory; the National Key Research and Development Program of China; Sanming Project of Medicine in Shenzhen China; and the High Level-Hospital Program, Health Commission of Guangdong Province, China.

Kidney organoids reveal redundancy in viral entry pathways during ACE2-dependent SARS-CoV-2 infection

With a high incidence of acute kidney injury among hospitalized COVID-19 patients, considerable attention has been focussed on whether SARS-CoV-2 specifically targets kidney cells to directly impact renal function, or whether renal damage is primarily an indirect outcome. To date, several studies have utilized kidney organoids to understand the pathogenesis of COVID-19, revealing the ability for SARS-CoV-2 to predominantly infect cells of the proximal tubule (PT), with reduced infectivity following administration of soluble ACE2. However, the immaturity of standard human kidney organoids represents a significant hurdle, leaving the preferred SARS-CoV-2 processing pathway, existence of alternate viral receptors, and the effect of common hypertensive medications on the expression of ACE2 in the context of SARS-CoV-2 exposure incompletely understood. Utilizing a novel kidney organoid model with enhanced PT maturity, genetic- and drug-mediated inhibition of viral entry and processing factors confirmed the requirement for ACE2 for SARS-CoV-2 entry but showed that the virus can utilize dual viral spike protein processing pathways downstream of ACE2 receptor binding. These include TMPRSS- and CTSL/CTSB-mediated non-endosomal and endocytic pathways, with TMPRSS10 likely playing a more significant role in the non-endosomal pathway in renal cells than TMPRSS2. Finally, treatment with the antihypertensive ACE inhibitor, lisinopril, showed negligible impact on receptor expression or susceptibility of renal cells to infection. This study represents the first in-depth characterization of viral entry in stem cell-derived human kidney organoids with enhanced PTs, providing deeper insight into the renal implications of the ongoing COVID-19 pandemic.

IMPORTANCE

Utilizing a human iPSC-derived kidney organoid model with improved proximal tubule (PT) maturity, we identified the mechanism of SARS-CoV-2 entry in renal cells, confirming ACE2 as the sole receptor and revealing redundancy in downstream cell surface TMPRSS- and endocytic Cathepsin-mediated pathways. In addition, these data address the implications of SARS-CoV-2 exposure in the setting of the commonly prescribed ACE-inhibitor, lisinopril, confirming its negligible impact on infection of kidney cells. Taken together, these results provide valuable insight into the mechanism of viral infection in the human kidney.

Outcome Comparison in Hospitalized COVID-19 Patients With and Without AKI

Aim

Patients hospitalized with COVID-19 have a higher incidence of Acute Kidney Injury (AKI) compared with non-COVID patients. Previous observational studies showed AKI in hospitalized patients with COVID-19 was associated with significant increased mortality rate. We conducted a retrospective cohort study in a large mid-Atlantic health system to investigate whether COVID-19 associated AKI during hospitalization would lead to worse outcomes in a predominant Black patient population, compared to COVID-19 without AKI.

Methods

We reviewed health records of patients (aged≥18 years) admitted with symptomatic COVID-19 between March 5, 2020, and Jun 3, 2020, in 9 acute care facilities within the MedStar Health system. Patients were followed up until 3 months after discharge. Primary outcome was inpatient mortality. Secondary outcomes were need for ICU level of care, need for intubation, length of ICU stay, length of hospital stay, need for renal replacement therapy, recovery of renal function.

Results

Among 1107 patients admitted with symptomatic COVID-19, the AKI incidence rate was 35 %. African American patients made up 63 % of the total patient population and 74 % of the total AKI population. Inpatient mortality in the AKI group and the non-AKI group was 163 (41.9 %) and 71 (9.9 %), respectively. COVID-19 patients with AKI had significant higher risk of in-patient mortality (OR, 4.71 [95 % CI, 3.38-6.62], P < 0.001), ICU admission (OR, 4.27 [95 % CI, 3.21-5.72], P < 0.001) and need of intubation (OR, 6.18 [95 % CI, 4.45-8.68], P < 0.001).

Conclusions

AKI in hospitalized patients with COVID-19 was associated with higher mortality rate, need for intubation and ICU admission compared to COVID-19 patients without AKI group.

The Role of Extracellular Vesicles in SARS-CoV-2-Induced Acute Kidney Injury: An Overview

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions worldwide since its outbreak in the winter of 2019. While extensive research has primarily focused on the deleterious respiratory effects of SARS-CoV-2 in recent years, its pan-tropism has become evident. Among the vital organs susceptible to SARS-CoV-2 infection is the kidney. Post SARS-CoV-2 infection, patients have developed coronavirus disease 19 (COVID-19), with reported incidences of COVID-19 patients developing acute kidney injury (AKI). Given COVID-19's multisystemic manifestation, our review focuses on the impact of SARS-CoV-2 infection within the renal system with an emphasis on the current hypotheses regarding the role of extracellular vesicles (EVs) in SARS-CoV-2 pathogenesis. Emerging studies have shown that SARS-CoV-2 can directly infect the kidney, whereas EVs are involved in the spreading of SARS-CoV-2 particles to other neighboring cells. Once the viral particles are within the kidney system, many proinflammatory signaling pathways are shown to be activated, resulting in AKI. Hence, clinical investigation of urinary proinflammatory components and total urinary extracellular vesicles (uEVs) with viral particles have been used to assess the severity of AKI in patients with COVID-19. Remarkedly, new emerging studies have shown the potential of mesenchymal stem cell-derived EVs (MSC-EVs) and ACE2-containing EVs as a hopeful therapeutic tool to inhibit SARS-CoV-2 RNA replication and block viral entry, respectively. Overall, understanding EVs' physiological role is crucial and hopefully will rejuvenate our therapeutic approach towards COVID-19 patients with AKI.

Potential Alternative Receptors for SARS-CoV-2-Induced Kidney Damage: TLR-4, KIM-1/TIM-1, and CD147

Kidney damage in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur even in patients with no underlying kidney disease. Signs of kidney problems can progress to a state that demands dialysis and hampering recovery. Although not without controversy, emerging evidence implicates direct infectivity of SARS-CoV-2 in the kidney. At the early stage of the pandemic, consideration was mainly on the well-recognized angiotensin-converting enzyme 2 (ACE2) receptor as being the site for viral interaction and subsequent cellular internalization. Despite the abundance of ACE2 receptors in the kidneys, researchers have expanded beyond ACE2 and identified novel viral entry pathways that could be advantageously explored as therapeutic targets. This review presents the potential involvement of toll-like receptor 4 (TLR-4), kidney injury molecule-1/T cell immunoglobulin mucin domain 1 (KIM-1/TIM-1), and cluster of differentiation 147 (CD147) in SARS-CoV-2-associated renal damage. In this context, we address the unresolved issues surrounding SARS-CoV-2 renal infectivity.

Multi-omics Approach in Kidney Transplant: Lessons Learned from COVID-19 Pandemic

Purpose of Review

Multi-omics approach has advanced our knowledge on transplantation-associated clinical outcomes, such as acute rejection and infection, and emerging omics data are becoming available in kidney transplant and COVID-19. Herein, we discuss updated findings of multi-omics data on kidney transplant outcomes, as well as COVID-19 and kidney transplant.

Recent Findings

Transcriptomics, proteomics, and metabolomics revealed various inflammation pathways associated with kidney transplantation-related outcomes and COVID-19. Although multi-omics data on kidney transplant and COVID-19 is limited, activation of innate immune pathways and suppression of adaptive immune pathways were observed in the active phase of COVID-19 in kidney transplant recipients.

Summary

Multi-omics analysis has led us to a deeper exploration and a more comprehensive understanding of key biological pathways in complex clinical settings, such as kidney transplantation and COVID-19. Future multi-omics analysis leveraging multi-center biobank collaborative will further advance our knowledge on the precise immunological responses to allograft and emerging pathogens.

Comparison of Short-Term Outcomes in Kidney Transplant Recipients from SARS-CoV-2-Infected versus Noninfected Deceased Donors

BACKGROUND

Acceptable post-transplant outcomes were reported in kidney transplant recipients from donors with coronavirus disease 2019 (COVID-19); however, there are no comparative studies with well-matched controls.

METHODS

This multicenter, prospective observational study, which included three transplant centers in the United States, enrolled 61 kidney recipients from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected deceased donors. Using optimal matching methods, we matched every recipient to three comparators receiving kidneys from SARS-CoV-2-negative deceased donors with otherwise highly similar characteristics in the same transplant centers to compare 6-month eGFR.

RESULTS

Among recipients of SARS-CoV-2-infected donor kidneys, one recipient died with a functional graft within 6 months. Mean 6-month eGFR was not significantly different between SARS-CoV-2-infected and noninfected donor groups (55±21 and 57±25 ml/min per 1.73 m 2 , respectively; P = 0.61). Six-month eGFR in recipients from SARS-CoV-2-infected donors who died of reasons other than COVID-19 was not significantly different from those from SARS-CoV-2-negative donors (58±22 and 56±25 ml/min per 1.73 m 2 , respectively; P = 0.51). However, recipients from donors who died of COVID-19 had significantly lower 6-month eGFR than those from SARS-CoV-2-negative donors (46±17 and 58±27 ml/min per 1.73 m 2 , respectively; P = 0.03). No donor-to-recipient SARS-CoV-2 transmission was observed.

CONCLUSIONS

Six-month eGFR was not significantly different between recipients of kidneys from SARS-CoV-2-infected and noninfected donors. However, those receiving kidneys from donors who died of COVID-19 had significantly lower 6-month eGFR. Donor-to-recipient SARS-CoV-2 transmission was not observed.

Peripheral Transcriptomics in Acute and Long-Term Kidney Dysfunction in SARS-CoV2 Infection

Background

Acute kidney injury (AKI) is common in hospitalized patients with SARS-CoV2 infection despite vaccination and leads to long-term kidney dysfunction. However, peripheral blood molecular signatures in AKI from COVID-19 and their association with long-term kidney dysfunction are yet unexplored.

Methods

In patients hospitalized with SARS-CoV2, we performed bulk RNA sequencing using peripheral blood mononuclear cells(PBMCs). We applied linear models accounting for technical and biological variability on RNA-Seq data accounting for false discovery rate (FDR) and compared functional enrichment and pathway results to a historical sepsis-AKI cohort. Finally, we evaluated the association of these signatures with long-term trends in kidney function.

Results

Of 283 patients, 106 had AKI. After adjustment for sex, age, mechanical ventilation, and chronic kidney disease (CKD), we identified 2635 significant differential gene expressions at FDR<0.05. Top canonical pathways were EIF2 signaling, oxidative phosphorylation, mTOR signaling, and Th17 signaling, indicating mitochondrial dysfunction and endoplasmic reticulum (ER) stress. Comparison with sepsis associated AKI showed considerable overlap of key pathways (48.14%). Using follow-up estimated glomerular filtration rate (eGFR) measurements from 115 patients, we identified 164/2635 (6.2%) of the significantly differentiated genes associated with overall decrease in long-term kidney function. The strongest associations were 'autophagy', 'renal impairment via fibrosis', and 'cardiac structure and function'.

Conclusions

We show that AKI in SARS-CoV2 is a multifactorial process with mitochondrial dysfunction driven by ER stress whereas long-term kidney function decline is associated with cardiac structure and function and immune dysregulation. Functional overlap with sepsis-AKI also highlights common signatures, indicating generalizability in therapeutic approaches.

SIGNIFICANCE STATEMENT

Peripheral transcriptomic findings in acute and long-term kidney dysfunction after hospitalization for SARS-CoV2 infection are unclear. We evaluated peripheral blood molecular signatures in AKI from COVID-19 (COVID-AKI) and their association with long-term kidney dysfunction using the largest hospitalized cohort with transcriptomic data. Analysis of 283 hospitalized patients of whom 37% had AKI, highlighted the contribution of mitochondrial dysfunction driven by endoplasmic reticulum stress in the acute stages. Subsequently, long-term kidney function decline exhibits significant associations with markers of cardiac structure and function and immune mediated dysregulation. There were similar biomolecular signatures in other inflammatory states, such as sepsis. This enhances the potential for repurposing and generalizability in therapeutic approaches.

Coronavirus disease 2019-associated thrombotic microangiopathy treated with plasma exchange and antihypertensive therapy in a patient with HIV: A case report with literature review

RATIONALE

Coronavirus disease 2019 (COVID-19) is an infectious disease that often causes complications in multiple organs and thrombosis due to abnormal blood coagulation. This case report aimed to describe the clinical course of COVID-19-associated thrombotic microangiopathy (TMA) and reviewed the comprehensive information on TMA, thrombotic thrombocytopenic purpura (TTP), and atypical hemolytic uremic syndrome associated with COVID-19 in the past literature.

PATIENT CONCERNS

A 46-year-old Japanese man was diagnosed with human immunodeficiency virus infection 10 years ago and treated with antiretroviral therapy. The patient presented with fever, malaise, hematuria, and bilateral upper abdominal discomfort for the past 4 days.

DIAGNOSES

COVID-19-associated TMA was diagnosed based on a positive polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 and laboratory findings such as thrombocytopenia, acute kidney injury, and hemolytic anemia. Malignant hypertension and human immunodeficiency virus infection were also considered as differential diagnoses of TMA.

INTERVENTIONS

Considering the possibility of TTP, plasma exchange was performed, and glucocorticoids were administered. Hemodialysis was performed for acute kidney injury. Antihypertensive drugs were administered to control the high blood pressure.

OUTCOMES

Platelet count and renal function improved, and hemodialysis was no longer required. The patient was in good general condition and was discharged from the hospital.

LESSONS

COVID-19-associated TMA should be considered as a differential diagnosis during the COVID-19 epidemic. Excessive inflammation and severe COVID-19 are not essential for TMA development. Early intervention using conventional TMA treatments, such as plasma exchange and corticosteroids, might be important in improving prognosis while differentiating between TTP and atypical hemolytic uremic syndrome. Antihypertensive therapy may be helpful in the treatment of COVID-19-associated TMA.

Podocytopathies related to either COVID-19 infection or its vaccination, our experience and literature review

Coronavirus disease 2019 (COVID-19) affects several organs including the kidney resulting in acute kidney injury (AKI) and variants of podocytopathies. From the beginning to the middle period of the COVID-19 pandemic, we have collected eight renal biopsies with various renal diseases including 4 podocytopathies. In addition, from the middle period to the near end of the COVID-19 pandemic, we have seen two of the patients who developed nephrotic syndrome following COVID-19 vaccination. Three of 4 podocytopathies were collapsing glomerulopathy (also called collapsing focal segmental glomerulosclerosis) and the fourth was a minimal change disease (MCD). Two of three collapsing glomerulopathy were found in African American patients, one of who was tested positive for having the high-risk allele APOL-1 G1. In addition, the two renal biopsies showed either MCD or replaced MCD following COVID-19 vaccination. MCD can be a rare complication following COVID-19 infection and COVID-19 vaccination, raising the question if there are similar antigens induced by the infection or by the vaccination that trigger the MCD. This article reports our experience of diagnosing podocytopathies related to either COVID-19 infection or its vaccination and provides a literature review regarding the incidence and potential pathophysiology in the field.

Infection-Related Glomerulonephritis in Children and Adults

Infection-related glomerulonephritis is an immunologically mediated glomerular injury after an infection. Glomerulonephritis may occur with the infection or after a variable latent period. Poststreptococcal glomerulonephritis (PSGN) is the prototype of infection-related glomerulonephritis. The streptococcal antigens, nephritis-associated plasmin-like receptor and streptococcal exotoxin B, have emerged as major players in the pathogenesis of PSGN. Although PSGN is the most common infection-related glomerulonephritis in children, in adults, glomerulonephritis is secondary to bacteria such as staphylococci, viruses such as hepatitis C, and human immunodeficiency virus, and, rarely, parasitic infections. Supportive therapy is the mainstay of treatment in most infection-related glomerulonephritis. Treatment of the underlying infection with specific antibiotics and antiviral medications is indicated in some infections. Parasitic infections, although rare, may be associated with significant morbidity. Poststreptococcal glomerulonephritis is a self-limiting condition with a good prognosis. However, bacterial, viral, and parasitic infections may be associated with significant morbidity and long-term consequences. Epidemiologic studies are required to assess the global burden of infection-related glomerulonephritis. A better understanding of the pathogenesis of infection-related glomerulonephritis may unravel more treatment options and preventive strategies.

Acute and chronic histopathological findings in renal biopsies in COVID-19

The dominant ICU admission diagnosis of COVID-19 patients is respiratory insufficiency, but 32-57% of hospitalized COVID-19 patients develop acute kidney injury (COVID-AKI). The renal histopathological changes accompanying COVID-AKI are not yet fully described. To obtain a detailed insight into renal histopathological features of COVID-19, we conducted a review including all studies reporting histopathological findings of diagnostic and postmortem kidney biopsies from patients with COVID-19 published between January 1, 2020, and January 31, 2021. A total of 89 diagnostic and 194 postmortem renal biopsies from individual patients in 39 published studies were investigated and were included in the analysis. In the diagnostic biopsy group, mean age was 56 years and AKI incidence was 96%. In the postmortem biopsy group, mean age was 69 years and AKI incidence was 80%. In the diagnostic biopsy group, the prevalence of acute glomerular diseases was 74%. The most common glomerular lesions were collapsing focal segmental glomerulosclerosis (c-FSGS) in 54% and thrombotic microangiopathy (TMA) in 9% of patients. TMA was also found in 10% of patients in the postmortem biopsy group. The most common acute tubular lesions was acute tubular necrosis (ATN) which was present in 87% of patients in the diagnostic and in 77% of patients in the postmortem biopsy group. Additionally, we observed a high prevalence of preexisting chronic lesions in both groups such as atherosclerosis and glomerulosclerosis. Histopathological changes in renal biopsies of COVID-19 patients show a heterogeneous picture with acute glomerular lesions, predominantly c-FSGS and TMA, and acute tubular lesions, predominantly ATN. In many patients, these lesions were present on a background of chronic renal injury.

Effects of Different Anticoagulation Doses on Moderate-to-Severe COVID-19 Pneumonia With Hypoxemia

Background COVID-19 is a prothrombotic disease that can cause thromboembolism and microthrombi, which could lead to multiorgan failure and death. Since COVID-19 is a relatively new disease, there are guidelines for anticoagulation dosing for COVID-19 patients without consensus on the dosing. We studied the effects of different doses of anticoagulation in hospitalized patients with COVID-19 pneumonia and hypoxemia on any differences in need for high-flow oxygen, mechanical ventilation, and mortality. We also analyzed the patient population who benefited most from anticoagulation. Methodology We performed a retrospective chart review of all patients who were admitted with the diagnosis of COVID-19 infection with positive polymerase chain reaction, pneumonia (confirmed either by chest X-ray or CT chest), and hypoxemia (oxygen saturation of <94%, while on room air). These patients were studied for outcomes (the need for high-flow oxygen, the requirement for mechanical ventilation, and overall mortality) for different doses of anticoagulation (prophylactic, escalated, and therapeutic). Results The sample consists of 132 subjects, predominantly males (116, 87%), with a mean age of 59 years and a standard deviation of 15. About one-third of the participants had diabetes, and more than 50% had hypertension. Additionally, 27 (20.3%) had a history of heart disease, and 70 (53%) of the subjects were admitted to the intensive care unit (ICU) at some point during the study. Among those admitted to the ICU, about 11 (8%) subjects required mechanical ventilation and 16 (12%) passed away during the study. Those who died had higher use of high-flow oxygen, noninvasive mechanical ventilation, and invasive mechanical ventilation and had a longer stay on mechanical ventilation. There was no significant difference in mortality or need for mechanical ventilation for any strategy of anticoagulation. Conclusions Different doses of anticoagulation did not show any statistically significant relationship between the need for mechanical ventilation and mortality. More patients on high-flow oxygen had received escalated doses of anticoagulation as compared to those who were not on high-flow oxygen. Anticoagulation levels did not have any statistically significant effect on overall survival of patients.

Kidney Damage in Long COVID: Studies in Experimental Mice

Signs and symptoms involving multiple organ systems which persist for weeks or months to years after the initial SARS-CoV-2 infection (also known as PASC or long COVID) are common complications of individuals with COVID-19. We recently reported pathophysiological changes in various organs post-acute infection of mice with mouse hepatitis virus-1 (MHV-1, a coronavirus) (7 days) and after long-term post-infection (12 months). One of the organs severely affected in this animal model is the kidney, which correlated well with human studies showing kidney injury post-SARS-CoV-2 infection. Our long-term post-infection pathological observation in kidneys includes the development of edema and inflammation of the renal parenchyma, severe acute tubular necrosis, and infiltration of macrophages and lymphocytes, in addition to changes observed in both acute and long-term post-infection, which include tubular epithelial cell degenerative changes, peritubular vessel congestion, proximal and distal tubular necrosis, hemorrhage in the interstitial tissue, and vacuolation of renal tubules. These findings strongly suggest the possible development of renal fibrosis, in particular in the long-term post-infection. Accordingly, we investigated whether the signaling system that is known to initiate the above-mentioned changes in kidneys in other conditions is also activated in long-term post-MHV-1 infection. We found increased TGF-β1, FGF23, NGAL, IL-18, HIF1-α, TLR2, YKL-40, and B2M mRNA levels in long-term post-MHV-1 infection, but not EGFR, TNFR1, BCL3, and WFDC2. However, only neutrophil gelatinase-associated lipocalin (NGAL) increased in acute infection (7 days). Immunoblot studies showed an elevation in protein levels of HIF1-α, TLR-2, and EGFR in long-term post-MHV-1 infection, while KIM-1 and MMP-7 protein levels are increased in acute infection. Treatment with a synthetic peptide, SPIKENET (SPK), which inhibits spike protein binding, reduced NGAL mRNA in acute infection, and decreased TGF-β1, BCL3 mRNA, EGFR, HIF1-α, and TLR-2 protein levels long-term post-MHV-1 infection. These findings suggest that fibrotic events may initiate early in SARS-CoV-2 infection, leading to pronounced kidney fibrosis in long COVID. Targeting these factors therapeutically may prevent acute or long-COVID-associated kidney complications.

Impacts of SARS-CoV-2 on diabetes mellitus: A pre and post pandemic evaluation

The coronavirus disease 2019 (COVID-19) pandemic caused by the novel beta coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) crippled the whole world and has resulted in large number of morbidity and mortality. The origin of the SARS-CoV-2 is still disputed. The risk of infection with SARS-CoV-2 is dependent on several risk factors as observed in many studies. The severity of the disease depends on many factors including the viral strain, host immunogenetics, environmental factors, host genetics, host nutritional status and presence of comorbidities like hypertension, diabetes, Chronic Obstructive Pulmonary Disease, cardiovascular disease, renal impairment. Diabetes is a metabolic disorder mainly characterized by hyperglycemia. Diabetic individuals are intrinsically prone to infections. SARS-CoV-2 infection in patients with diabetes result in β-cell damage and cytokine storm. Damage to the cells impairs the equilibrium of glucose, leading to hyperglycemia. The ensuing cytokine storm causes insulin resistance, especially in the muscles and liver, which also causes a hyperglycemic state. All of these increase the severity of COVID-19. Genetics also play pivotal role in disease pathogenesis. This review article focuses from the probable sources of coronaviruses and SARS-CoV-2 to its impacts on individuals with diabetes and host genetics in pre- and post-pandemic era.

Post-COVID-19 Syndrome Mechanisms, Prevention and Management

As the population of patients recovering from COVID-19 grows, post COVID-19 challenges are recognizing by ongoing evidences at once. Long COVID is defined as a syndrome with a range of persistent symptoms that remain long after (beyond 12 weeks) the acute SARS-CoV-2 infection. Studies have shown that long COVID can cause multi-organ damages with a wide spectrum of manifestations. Many systems, but not limited to, including respiratory, cardiovascular, nervous, gastrointestinal, and musculoskeletal systems, are involved in long COVID. Fatigue and dyspnea are the most common symptoms of long COVID. Long COVID-19 may be driven by tissue damage caused by virus-specific pathophysiologic changes or secondary to pathological long-lasting inflammatory response because of viral persistence, immune dysregulation, and autoimmune reactions. Some risk factors like sex and age, more than five early symptoms, and specific biomarkers have been revealed as a probable long COVID predicator discussed in this review. It seems that vaccination is the only way for prevention of long COVID and it can also help patients who had already long COVID. Managing long COVID survivors recommended being in a multidisciplinary approach, and a framework for identifying those at high risk for post-acute COVID-19 must be proposed. Possible therapeutic options and useful investigation tools for follow-up are suggested in this review. In sum, as evidence and researches are regularly updated, we provide the current understanding of the epidemiology, clinical manifestation, suspected pathophysiology, associated risk factors, and treatment options of long COVID in this review.

Complement-Mediated Thrombotic Microangiopathy Related to COVID-19 or SARS-CoV-2 Vaccination

Introduction

Infectious diseases and vaccinations are trigger factors for thrombotic microangiopathy. Consequently, the COVID-19 pandemic could have an effect on disease manifestation or relapse in patients with atypical hemolytic syndrome/complement-mediated thrombotic microangiopathy (aHUS/cTMA).

Methods

We employed the Vienna TMA cohort database to examine the incidence of COVID-19 related and of SARS-CoV-2 vaccination-related relapse of aHUS/cTMA among patients previously diagnosed with aHUS/cTMA during the first 2.5 years of the COVID-19 pandemic. We calculated incidence rates, including respective confidence intervals (CIs) and used Cox proportional hazard models for comparison of aHUS/cTMA episodes following infection or vaccination.

Results

Among 27 patients with aHUS/cTMA, 13 infections triggered 3 (23%) TMA episodes, whereas 70 vaccinations triggered 1 TMA episode (1%; odds ratio 0.04; 95% CI 0.003-0.37, P = 0.01). In total, the incidence of TMA after COVID-19 or SARS-CoV-2 vaccination was 6 cases per 100 patient years (95% CI 0.017-0.164) (4.5/100 patient years for COVID-19 and 1.5/100 patient years for SARS-CoV-2 vaccination). The mean follow-up time was 2.31 ± 0.26 years (total amount: 22,118 days; 62.5 years) to either the end of the follow-up or TMA relapse (outcome). Between 2012 and 2022 we did not find a significant increase in the incidence of aHUS/cTMA.

Conclusion

COVID-19 is associated with a higher risk for aHUS/cTMA recurrence when compared to SARS-CoV-2 vaccination. Overall, the incidence of aHUS/cTMA after COVID-19 infection or SARS-CoV-2 vaccination is low and comparable to that described in the literature.

Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Kidney transplantation is the first-choice treatment for end-stage renal disease (ESRD). Kidney transplant recipients (KTRs) are at higher risk of experiencing a life-threatening event requiring intensive care unit (ICU) admission, mainly in the late post-transplant period (more than 6 months after transplantation). Urosepsis and bloodstream infections account for almost half of ICU admissions in this population; in addition, potential side effects related to immunosuppressive treatment should be accounted for cytotoxic and ischemic changes induced by calcineurin inhibitor (CNI), sirolimus/CNI-induced thrombotic microangiopathy and posterior reversible encephalopathy syndrome. Throughout the ICU stay, Acute Kidney Injury (AKI) incidence is common and ranges from 10% to 80%, and up to 40% will require renal replacement therapy. In-hospital mortality can reach 30% and correlates with acute illness severity and admission diagnosis. Graft survival is subordinated to baseline estimated glomerular filtration rate (eGFR), clinical presentation, disease severity and potential drug nephrotoxicity. The present review aims to define the impact of AKI events on short- and long-term outcomes in KTRs, focusing on the epidemiologic data regarding AKI incidence in this subpopulation; the pathophysiological mechanisms underlying AKI development and potential AKI biomarkers in kidney transplantation, graft and patients' outcomes; the current diagnostic work up and management of AKI; and the modulation of immunosuppression in ICU-admitted KTRs.

FSGS and COVID-19 in Non-African American Patients

Collapsing Focal Segmental Glomerulosclerosis (FSGS) has been reported relatively frequently in African American (AA) patients with coronavirus disease 2019 (COVID-19), and it is associated almost always with Apolipoprotein L gen 1 (APOL1) high-risk variants. We reviewed the published literature from April 2020 to November 2022 searching for non-African American (non-AA) patients with FSGS associated with COVID-19 (eight White patients, six Hispanic patients, three Asian patients, one Indian patient, and one Asian Indian patient). The following histologic patterns were found: collapsing (n=11), not otherwise specified (n=5), tip (n=2), and perihilar (n=1). Fifteen of the 19 patients had AKI. The APOL1 genotype was reported in only six of the 19 non-AA patients. Three of them (two Hispanic patients and one White patient) with collapsing FSGS had high-risk APOL1 variants. The other three patients (two White patients and one Hispanic patient with the collapsing variant, tip variant, and not otherwise specified) had low-risk APOL1 variants. Among 53 African American patients with collapsing FSGS associated with COVID-19, 48 had high-risk APOL1 variants and five had low-risk APOL1 variants. We conclude that in non-AA patients, FSGS is a rare complication of COVID-19. FSGS associated with COVID-19 can occur rarely with low-risk APOL1 variants in non-AA and AA patients. Non-AA patients reported to be associated with high-risk APOL1 variants possibly reflect inaccuracy of self-reported race with AA admixture because of unknown ancestry. Given the importance of APOL1 in the pathogenesis of FSGS associated with viral infection and to avoid racial bias, it seems appropriate that APOL1 testing be considered in patients with FSGS associated with COVID-19, regardless of self-reported race.

"Acute kidney injury in critically ill patients with COVID-19: The AKICOV multicenter study in Catalonia"

This study describes the incidence, evolution and prognosis of acute kidney injury (AKI) in critical COVID-19 during the first pandemic wave. We performed a prospective, observational, multicenter study of confirmed COVID-19 patients admitted to 19 intensive care units (ICUs) in Catalonia (Spain). Data regarding demographics, comorbidities, drug and medical treatment, physiological and laboratory results, AKI development, need for renal replacement therapy (RRT) and clinical outcomes were collected. Descriptive statistics and logistic regression analysis for AKI development and mortality were used. A total of 1,642 patients were enrolled (mean age 63 (15.95) years, 67.5% male). Mechanical ventilation (MV) was required for 80.8% and 64.4% of these patients, who were in prone position, while 67.7% received vasopressors. AKI at ICU admission was 28.4% and increased to 40.1% during ICU stay. A total of 172 (10.9%) patients required RRT, which represents 27.8% of the patients who developed AKI. AKI was more frequent in severe acute respiratory distress syndrome (ARDS) ARDS patients (68% vs 53.6%, p<0.001) and in MV patients (91.9% vs 77.7%, p<0.001), who required the prone position more frequently (74.8 vs 61%, p<0.001) and developed more infections. ICU and hospital mortality were increased in AKI patients (48.2% vs 17.7% and 51.1% vs 19%, p <0.001) respectively). AKI was an independent factor associated with mortality (IC 1.587-3.190). Mortality was higher in AKI patients who required RRT (55.8% vs 48.2%, p <0.04). Conclusions There is a high incidence of AKI in critically ill patients with COVID-19 disease and it is associated with higher mortality, increased organ failure, nosocomial infections and prolonged ICU stay.

Sequelae of long COVID, known and unknown: A review of updated information

Over three years have passed since the COVID-19 pandemic started. The dangerousness and impact of COVID-19 should definitely not be ignored or underestimated. Other than the symptoms of acute infection, the long-term symptoms associated with SARS-CoV-2 infection, which are referred to here as "sequelae of long COVID (LC)", are also a conspicuous global public health concern. Although such sequelae were well-documented, the understanding of and insights regarding LC-related sequelae remain inadequate due to the limitations of previous studies (the follow-up, methodological flaws, heterogeneity among studies, etc.). Notably, robust evidence regarding diagnosis and treatment of certain LC sequelae remain insufficient and has been a stumbling block to better management of these patients. This awkward situation motivated us to conduct this review. Here, we comprehensively reviewed the updated information, particularly focusing on clinical issues. We attempt to provide the latest information regarding LC-related sequelae by systematically reviewing the involvement of main organ systems. We also propose paths for future exploration based on available knowledge and the authors' clinical experience. We believe that these take-home messages will be helpful to gain insights into LC and ultimately benefit clinical practice in treating LC-related sequelae.

Acute Kidney Injury Associated with Severe SARS-CoV-2 Infection: Risk Factors for Morbidity and Mortality and a Potential Benefit of Combined Therapy with Tocilizumab and Corticosteroids

Background: Acute kidney injury (AKI) is a common complication in patients with severe COVID-19. Methods: We retrospectively reviewed 249 patients admitted to an intensive care unit (ICU) during the first wave of the pandemic to determine risk factors for AKI. Demographics, comorbidities, and clinical and outcome variables were obtained from electronic medical records. Results: Univariate analysis revealed older age, higher admission serum creatinine, elevated Sequential Organ Failure Assessment (SOFA) score, elevated admission D-Dimer, elevated CRP on day 2, mechanical ventilation, vasopressor requirement, and azithromycin usage as significant risk factors for AKI. Multivariate analysis demonstrated that higher admission creatinine (p = 0.0001, OR = 2.41, 95% CI = 1.56–3.70), vasopressor requirement (p = 0.0001, OR = 3.20, 95% CI = 1.69–5.98), elevated admission D-Dimer (p = 0.008, OR = 1.0001, 95% CI = 1.000–1.001), and elevated C-reactive protein (CRP) on day 2 (p = 0.033, OR = 1.0001, 95% CI = 1.004–1.009) were independent risk factors. Conversely, the combined use of Tocilizumab and corticosteroids was independently associated with reduced AKI risk (p = 0.0009, OR = 0.437, 95% CI = 0.23–0.81). Conclusion: This study confirms the high rate of AKI and associated mortality among COVID-19 patients admitted to ICUs and suggests a role for inflammation and/or coagulopathy in AKI development. One should consider the possibility that early administration of anti-inflammatory agents, as is now routinely conducted in the management of COVID-19-associated acute respiratory distress syndrome, may improve clinical outcomes in patients with AKI.

A specific molecular signature in SARS-CoV-2-infected kidney biopsies

Acute kidney injury is one of the most important complications in patients with COVID-19 and is considered a negative prognostic factor with respect to patient survival. The occurrence of direct infection of the kidney by SARS-CoV-2, and its contribution to the renal deterioration process, remain controversial issues. By studying 32 renal biopsies from patients with COVID-19, we verified that the major pathological feature of COVID-19 is acute tubular injury (ATI). Using single-molecule fluorescence in situ hybridization, we showed that SARS-CoV-2 infected living renal cells and that infection, which paralleled renal angiotensin-converting enzyme 2 expression levels, was associated with increased death. Mechanistically, a transcriptomic analysis uncovered specific molecular signatures in SARS-CoV-2-infected kidneys as compared with healthy kidneys and non-COVID-19 ATI kidneys. On the other hand, we demonstrated that SARS-CoV-2 and hantavirus, 2 RNA viruses, activated different genetic networks despite triggering the same pathological lesions. Finally, we identified X-linked inhibitor of apoptosis-associated factor 1 as a critical target of SARS-CoV-2 infection. In conclusion, this study demonstrated that SARS-CoV-2 can directly infect living renal cells and identified specific druggable molecular targets that can potentially aid in the design of novel therapeutic strategies to preserve renal function in patients with COVID-19.

Long-term interplay between COVID-19 and chronic kidney disease

PURPOSE

The COVID-19 pandemic may have an impact on the long-term kidney function of survivors. The clinical relevance is not clear.

METHODS

This review summarises the currently published data.

RESULTS

There is a bidirectional relationship between chronic kidney disease and COVID-19 disease. Chronic kidney diseases due to primary kidney disease or chronic conditions affecting kidneys increase the susceptibility to COVID-19 infection, the risks for progression and critical COVID-19 disease (with acute or acute-on-chronic kidney damage), and death. Patients who have survived COVID-19 face an increased risk of worse kidney outcomes in the post-acute phase of the disease. Of clinical significance, COVID-19 may predispose surviving patients to chronic kidney disease, independently of clinically apparent acute kidney injury (AKI). The increased risk of post-acute renal dysfunction of COVID-19 patients can be graded according to the severity of the acute infection (non-hospitalised, hospitalised or ICU patients). The burden of chronic kidney disease developing after COVID-19 is currently unknown.

CONCLUSION

Post-acute COVID-19 care should include close attention to kidney function. Future prospective large-scale studies are needed with long and complete follow-up periods, assessing kidney function using novel markers of kidney function/damage, urinalysis and biopsy studies.

Crosstalk between COVID-19 Infection and Kidney Diseases: A Review on the Metabolomic Approaches

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a respiratory disorder. Various organ injuries have been reported in response to this virus, including kidney injury and, in particular, kidney tubular injury. It has been discovered that infection with the virus does not only cause new kidney disease but also increases treatment difficulty and mortality rates in people with kidney diseases. In individuals hospitalized with COVID-19, urinary metabolites from several metabolic pathways are used to distinguish between patients with acute kidney injury (AKI) and those without. This review summarizes the pathogenesis, pathophysiology, treatment strategies, and role of metabolomics in relation to AKI in COVID-19 patients. Metabolomics is likely to play a greater role in predicting outcomes for patients with kidney disease and COVID-19 with varying levels of severity in the near future as data on metabolic profiles expand rapidly. Here, we also discuss the correlation between COVID-19 and kidney diseases and the available metabolomics approaches.

Exploring the potential mechanisms of impairment on genitourinary system associated with coronavirus disease 2019 infection: Bioinformatics and molecular simulation analyses

Objective

The novel coronavirus (severe acute respiratory syndrome coronavirus 2) has been spreading worldwide since December 2019, posing a serious danger to human health and socioeconomic development. A large number of clinical trials have revealed that coronavirus disease 2019 (COVID-19) results in multi-organ damage including the urogenital system. This study aimed to explore the potential mechanisms of genitourinary damage associated with COVID-19 infection through bioinformatics and molecular simulation analysis.

Methods

We used multiple publicly available databases to explore the expression patterns of ACE2, TMPRSS2, and CD147 (Basigin [BSG]) in major organs in the healthy and disease-specific populations, particularly the genitourinary organs. Single-cell RNA sequencing was used to analyze the cell-specific expression patterns of ACE2, TMPRSS2, CD147, cytokine receptors, and cytokine interacting proteins in genitourinary organs, such as the bladder, kidney, prostate, and testis. Additionally, gene set enrichment analysis was used to investigate the relationship between testosterone levels and COVID-19 vulnerability in patients with prostate cancer.

Results

The results revealed that ACE2, TMPRSS2, and CD147 were highly expressed in normal urogenital organs. Then, they were also highly expressed in multiple tumors and chronic kidney diseases. Additionally, ACE2, TMPRSS2, and CD147 were significantly expressed in a range of cells in urogenital organs according to single-cell RNA sequencing. Cytokine receptors and cytokine interacting proteins, especially CCL2, JUN, and TIMP1, were commonly highly expressed in urogenital organs. Finally, gene set enrichment analysis results showed that high testosterone levels in prostate cancer patients were significantly related to the JAK/STAT signaling pathway and the Toll-like receptor signaling pathway which were associated with COVID-19.

Conclusion

Our study provides new insights into the potential mechanisms of severe acute respiratory syndrome coronavirus 2 damage to urogenital organs from multiple perspectives, which may draw the attention of urologists to COVID-19 and contribute to the development of targeted drugs.

SARS-CoV-2 infection of kidney tissues from severe COVID-19 patients

BACKGROUND

Coronavirus disease 2019 (COVID-19) caused by infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) manifests diverse clinical pathologies involving multiple organs. While the respiratory tract is the primary SARS-CoV-2 target, acute kidney injury is common in COVID-19 patients, displaying as acute tubular necrosis (ATN) resulting from focal epithelial necrosis and eosinophilia, glomerulosclerosis, and autolysis of renal tubular cells. However, whether any renal cells are infected by SARS-CoV-2 and the mechanism involved in the COVID-19 kidney pathology remain unclear.

METHODS

Kidney tissues obtained at autopsy from four severe COVID-19 patients and one healthy subject were examined by hematoxylin and eosin staining. Indirect immunofluorescent antibody assay was performed to detect SARS-CoV-2 spike protein S1 and nonstructural protein 8 (NSP8) together with markers of different kidney cell types and immune cells to identify the infected cells.

RESULTS

Renal parenchyma showed tissue injury comprised of ATN and glomerulosclerosis. Positive staining of S1 protein was observed in renal parenchymal and tubular epithelial cells. Evidence of viral infection was also observed in innate monocytes/macrophages and NK cells. Positive staining of NSP8, which is essential for viral RNA synthesis and replication, was confirmed in renal parenchymal cells, indicating the presence of active viral replication in the kidney.

CONCLUSIONS

In fatal COVID-19 kidneys, there are SARS-CoV-2 infection, minimally infiltrated innate immune cells, and evidence of viral replication, which could contribute to tissue damage in the form of ATN and glomerulosclerosis.

Resultados en receptores de trasplante renal de donantes cadavéricos con infección por SARS-CoV-2: Una serie de casos en un centro de trasplante en Colombia

Introducción. La pandemia por COVID-19 ha causado la muerte de 6,5 millones de personas en el mundo y la donación de órganos se ha visto ampliamente afectada, reflejándose en una disminución importante en el número de trasplantes. Colombia no ha sido ajena a dicha problemática. Ante este desafío, el Instituto Nacional de Salud ha permitido tomar donantes cadavéricos con reacción en cadena de la polimerasa con transcripción reversa (RT-PCR) positiva para Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), sin enfermedad activa. El objetivo de este estudio fue describir una serie de pacientes trasplantados de riñón con donantes cadavéricos con RT-PCR SARS-CoV-2 positivo y sus principales desenlaces clínicos. Métodos. Serie de casos de pacientes que fueron llevados a trasplante renal con donante cadavérico con SARSCoV-2 positivo, sin enfermedad activa, entre mayo y agosto de 2022. Se recolectaron las variables demográficas y clínicas y se evaluó la infección y la mortalidad asociada a SARS-CoV-2. Resultados. Un total de 5 receptores de trasplante renal con 5 donantes cadavéricos SARS-CoV-2 positivos fueron evaluados. No se presentó mortalidad ni pérdida del injerto renal. Se registraron dos casos de función retardada del injerto y un caso de rechazo agudo. Ninguno de los pacientes presentó RT-PCR SARS-CoV-2 positiva en el seguimiento posterior al trasplante. Conclusión. Con nuestra serie de casos mostramos que el trasplante de riñón proveniente de donante cadavérico con prueba positiva para RT-PCR SARS-CoV-2, sin evidencia de enfermedad COVID-19 activa, es un procedimiento seguro y una estrategia eficaz para aumentar el número de donantes en pandemia.

COVID-19 and Kidney Disease

COVID-19 can cause acute kidney injury and may cause or exacerbate chronic kidney diseases, including glomerular diseases. SARS-CoV-2 infection of kidney cells has been reported, but it remains unclear if viral infection of kidney cells causes disease. The most important causes of kidney injury in patients with COVID-19 include impaired renal perfusion and immune dysregulation. Chronic kidney disease, especially kidney failure with kidney replacement therapy and kidney transplant, is associated with markedly increased COVID-19 mortality. Persons with severe kidney disease have been excluded from most clinical trials of COVID-19 therapies, so therapeutic approaches must be extrapolated from studies of patients without kidney disease. Some medications used to treat COVID-19 should be avoided or used at reduced dosages in patients with severe kidney disease and in kidney transplant recipients. Additional research is needed to determine the optimal strategies to prevent and treat COVID-19 in patients with kidney disease.

Role of Renal Parenchyma Attenuation and Perirenal Fat Stranding in Chest CT of Hospitalized Patients with COVID-19

BACKGROUND

Chest CT on coronavirus disease (COVID-19) has been extensively investigated. Acute kidney injury (AKI) has been widely described among COVID patients, but the role of kidney imaging has been poorly explored. The aim of this study is to clarify the role of opportunistic kidney assessment on non-enhanced chest CT.

METHODS

We collected data on patients with COVID-19 consecutively admitted to our institution who underwent chest CT (including the upper parts of kidneys as per protocol). Three ROIs of 0.5-0.7 cm² were positioned in every kidney. The values of renal parenchyma attenuation (RPA) and the presence of perirenal fat stranding (PFS) were analyzed. The primary and secondary outcomes were the occurrence of AKI and death.

RESULTS

86 patients with COVID-19 and unenhanced chest CT were analyzed. The cohort was split into CT RPA quartiles. Patients with a CT RPA <24 HU were more likely to develop AKI when compared with other patients (χ² = 2.77, p = 0.014): at multivariate logistic regression analysis, being in the first quartile of CT RPA was independently associated with a four times higher risk of AKI (HR 4.56 [95% CI 1.27-16.44, p = 0.020). Within a mean 22 ± 15 days from admission, 32 patients died (37.2%). Patients with PFS were more likely to die as compared to patients without it (HR 3.90 [95% CI 1.12-13.48], p = 0.031).

CONCLUSIONS

Detection of low RPA values and of PFS in COVID-19 patients independently predicts, respectively, the occurrence of AKI and an increased risk for mortality. Therefore, opportunistic kidney assessment during chest CT could help physicians in defining diagnostic and therapeutic strategies.

Renal biopsy in systemic infections: expect the unexpected

Infection-related glomerulonephritis is well recognized in patients with ongoing infections. It can be missed, however, if the infection is unusual or undetected. We present three cases where the renal biopsy findings prompted the identification or treatment of systemic infections.Case 1: A 84-year-old male presented with acute kidney injury (AKI) and IgA vasculitis on skin biopsy. A renal biopsy showed active glomerulonephritis with abundant neutrophils and predominantly mesangial immune complex deposits containing IgA. The findings prompted an infectious workup which was positive for COVID-19, suggesting exacerbation of IgA nephropathy by recent COVID-19 infection. Case 2: A 31-year-old female status post kidney transplant for granulomatosis with polyangiitis (GPA) had recent pregnancy with preterm delivery, disseminated herpes simplex virus (HSV) infection with HSV hepatitis, E. coli on urine culture, and AKI. A renal biopsy showed proliferative glomerulonephritis with subendothelial and mesangial immune complex deposits containing IgG and C3. The findings were most consistent with infection-related immune complex glomerulonephritis, most likely HSV-related. Case 3: A 78-year-old female presented with AKI, proteinuria, hematuria, and positive p-ANCA. Clinically, ANCA vasculitis was suspected, and renal biopsy did show focal, segmental, necrotizing glomerulonephritis. However, immunofluorescence and electron microscopy showed IgM-rich deposits in the mesangium. The unusual presentation prompted an infectious workup including a Bartonella antibody panel which showed very high titers, suggesting Bartonella endocarditis.Infection-related glomerulonephritis has a wide variety of presentations histologically and clinically. The three cases we present here emphasize the importance of recognizing these entities to help guide treatment and improve patient care.

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.

Evaluation of the relationship between acute kidney injury and renin angiotensin system inhibition in COVID-19 patients

OBJECTIVE

In patients with coronavirus disease 2019 (COVID-19), acute kidney injury (AKI) may alter the clinical course and outcome of the disease. In this study, the association of AKI with renin angiotensin system (RAS) inhibitor treatment and its clinical consequences were examined in COVID-19 patients admitted to our hospital during the initial stages of the pandemic.

METHODS

A total of 407 patients between 18 and 85 years of age (202 male and 205 female) admitted to the Umraniye Research And Training Hospital between May 2020 and August 2020 with a diagnosis of COVID-19 were included in the study. Patients were categorized as follows: Group 1, subjects with no chronic conditions (n=150); and Group 2, subjects with comorbid conditions (n=257). Group 2 was subdivided into Group 2A (receiving angiotensin receptor blocker [ARB])/(angiotensin converting enzyme inhibitor [ACEI], n=81), and Group 2B (not receiving ARB/ACEI, n=176).

RESULTS

Hypertension was the most frequent comorbid condition (36.4%). There was no difference in survival rates between the patients who used RAS inhibitor and the ones who did not based on log rank test (p=0.342). Fifty-four patients (13.4%) had developed AKI during the time frame of the disease. In patients with chronic diseases such as hypertension, the use of RAS inhibitory medication was not associated with developing AKI (OR 95% CI: 0.317-1.358; p=0.256). The survival rate of the patients with AKI was significantly lower than patients without AKI (p<0.0001).

CONCLUSION

COVID-19 may cause renal injury represents a risk factor for mortality. Therefore, detection of renal injury has a particular prognostic importance.

SARS-CoV-2 infection of companion animals in Egypt and its risk of spillover

BACKGROUND

Reverse zoonoses occur because of interactions between humans and animals. Homology of ACE-2 cell receptors in different hosts and high mutation rate of SARS-CoV-2 enhance viral transmission among species.

OBJECTIVES

This study aimed to investigate spillover of SARS-CoV-2 between humans and companion animals.

METHODS

A cross-sectional study was constructed using nasopharyngeal/oropharyngeal swabs, serum and blood samples collected from 66 companion animals (33 cats and 33 dogs) that were in contact with SARS-CoV-2-positive owners from December 2020 to March 2021. Swabs were screened by rRT-PCR and some positive cases were confirmed by partial spike gene sequencing. Clinical pathology and pathological studies were also performed.

RESULTS

Our findings revealed that 30% of cats (10/33) and 24% of dogs (8/33) were SARS-CoV-2 positive. While 33% of these animals were asymptomatic (6/18), 28% showed mild respiratory signs (5/18) and 39% displayed severe respiratory signs (7/18) including 4 dead cats 40% (4/10). Partial spike gene sequencing of 6 positive samples collected in December 2020 were identical to SARS-CoV-2 that was detected in humans in Egypt in that time frame. Clinical pathology findings revealed thrombocytopenia, lymphocytopenia, as well as elevated levels of D-dimer, LDH, CRP, and ferritin. Post-mortem and histopathological examinations illustrated multisystemic effects.

CONCLUSIONS

There is a potential occurrence of SARS-CoV-2 spillover between humans and pet animals.

IMPACTS

The present study highlighted the potential occurrence of SARS-CoV-2 spillover between humans and their companion animals. Biosecurity measures should be applied to decrease spread of SARS-CoV-2 among humans and pet animals.

COVID-19 and Acute Kidney Injury - Direct and Indirect Pathophysiological Mechanisms Underlying Lesion Development

COVID-19 is a pandemic disease caused by the SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) responsible for millions of deaths worldwide. Although the respiratory system is the main target of COVID-19, the disease can affect other organs, including the kidneys. Acute Kidney Injury (AKI), commonly seen in patients infected with COVID-19, has a multifactorial cause. Several studies associate this injury with the direct involvement of the virus in renal cells and the indirect damage stimulated by the infection. The direct cytopathic effects of SARS-CoV-2 are due to the entry and replication of the virus in renal cells, changing several regulatory pathways, especially the renin-angiotensin-aldosterone system (RAAS), with repercussions on the kallikrein-kinin system (KKS). Furthermore, the virus can deregulate the immune system, leading to an exaggerated response of inflammatory cells, characterizing the state of hypercytokinemia. The such exaggerated inflammatory response is commonly associated with hemodynamic changes, reduced renal perfusion, tissue hypoxia, generation of reactive oxygen species (ROS), endothelial damage, and coagulopathies, which can result in severe damage to the renal parenchyma. Thereby, understanding the molecular mechanisms and pathophysiology of kidney injuries induced by SARS-COV-2 is of fundamental importance to obtaining new therapeutic insights for the prevention and management of AKI.

Tip Lesion Variant of Focal and Segmental Glomerulosclerosis in a COVID-19 Patient

Acute kidney injury is a common complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Several pathologic findings are continually being reported, showing a probably multifactorial etiology. The authors present a case of a patient diagnosed with a tip lesion variant of focal segmental glomerulosclerosis (FSGS) in the setting of COVID-19. A 43-year-old African American female with no known renal disease presented to the emergency department with a 6-day history of fatigue, headache, hypoageusia, myalgia, cough, nausea, and vomiting. Laboratory tests confirmed SARS-CoV-2 infection. During hospitalization, there was a progressive decline in kidney function and evidence of nephrotic-range proteinuria without nephrotic syndrome. Biopsy specimen showed a tip lesion variant of FSGS. Genetic test revealed a homozygous variant of uncertain clinical significance (c.397G>A [p.V133M]) in the epithelial membrane protein 2 (EMP2) gene. To our knowledge, this is the first case report of a tip lesion in a COVID-19 patient with no renal history. More studies are warranted to define susceptible groups and identify the detailed mechanisms of COVID-19-related kidney disease that would allow for specific management of this complication.

Development and validation of a nomogram for the early prediction of acute kidney injury in hospitalized COVID-19 patients

Introduction

Acute kidney injury (AKI) is a prevalent complication of coronavirus disease 2019 (COVID-19) and is closely linked with a poorer prognosis. The aim of this study was to develop and validate an easy-to-use and accurate early prediction model for AKI in hospitalized COVID-19 patients.

Methods

Data from 480 COVID-19-positive patients (336 in the training set and 144 in the validation set) were obtained from the public database of the Cancer Imaging Archive (TCIA). The least absolute shrinkage and selection operator (LASSO) regression method and multivariate logistic regression were used to screen potential predictive factors to construct the prediction nomogram. Receiver operating curves (ROC), calibration curves, as well as decision curve analysis (DCA) were adopted to assess the effectiveness of the nomogram. The prognostic value of the nomogram was also examined.

Results

A predictive nomogram for AKI was developed based on arterial oxygen saturation, procalcitonin, C-reactive protein, glomerular filtration rate, and the history of coronary artery disease. In the training set, the nomogram produced an AUC of 0.831 (95% confidence interval [CI]: 0.774-0.889) with a sensitivity of 85.2% and a specificity of 69.9%. In the validation set, the nomogram produced an AUC of 0.810 (95% CI: 0.737-0.871) with a sensitivity of 77.4% and a specificity of 78.8%. The calibration curve shows that the nomogram exhibited excellent calibration and fit in both the training and validation sets. DCA suggested that the nomogram has promising clinical effectiveness. In addition, the median length of stay (m-LS) for patients in the high-risk group for AKI (risk score ≥ 0.122) was 14.0 days (95% CI: 11.3-16.7 days), which was significantly longer than 8.0 days (95% CI: 7.1-8.9 days) for patients in the low-risk group (risk score <0.122) (hazard ratio (HR): 1.98, 95% CI: 1.55-2.53, p < 0.001). Moreover, the mortality rate was also significantly higher in the high-risk group than that in the low-risk group (20.6 vs. 2.9%, odd ratio (OR):8.61, 95%CI: 3.45-21.52).

Conclusions

The newly constructed nomogram model could accurately identify potential COVID-19 patients who may experience AKI during hospitalization at the very beginning of their admission and may be useful for informing clinical prognosis.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Urinary angiotensin-converting enzyme 2 and metabolomics in COVID-19-mediated kidney injury

Background

Angiotensin-converting enzyme 2 (ACE2), the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is highly expressed in the kidneys. Beyond serving as a crucial endogenous regulator of the renin-angiotensin system, ACE2 also possess a unique function to facilitate amino acid absorption. Our observational study sought to explore the relationship between urine ACE2 (uACE2) and renal outcomes in coronavirus disease 2019 (COVID-19).

Methods

In a cohort of 104 patients with COVID-19 without acute kidney injury (AKI), 43 patients with COVID-19-mediated AKI and 36 non-COVID-19 controls, we measured uACE2, urine tumour necrosis factor receptors I and II (uTNF-RI and uTNF-RII) and neutrophil gelatinase-associated lipocalin (uNGAL). We also assessed ACE2 staining in autopsy kidney samples and generated a propensity score-matched subgroup of patients to perform a targeted urine metabolomic study to describe the characteristic signature of COVID-19.

Results

uACE2 is increased in patients with COVID-19 and further increased in those that developed AKI. After adjusting uACE2 levels for age, sex and previous comorbidities, increased uACE2 was independently associated with a >3-fold higher risk of developing AKI [odds ratio 3.05 (95% confidence interval 1.23‒7.58), P = .017]. Increased uACE2 corresponded to a tubular loss of ACE2 in kidney sections and strongly correlated with uTNF-RI and uTNF-RII. Urine quantitative metabolome analysis revealed an increased excretion of essential amino acids in patients with COVID-19, including leucine, isoleucine, tryptophan and phenylalanine. Additionally, a strong correlation was observed between urine amino acids and uACE2.

Conclusions

Elevated uACE2 is related to AKI in patients with COVID-19. The loss of tubular ACE2 during SARS-CoV-2 infection demonstrates a potential link between aminoaciduria and proximal tubular injury.

Decreased renal perfusion during acute kidney injury in critical COVID-19 assessed by magnetic resonance imaging: a prospective case control study

BACKGROUND

Renal hypoperfusion has been suggested to contribute to the development of acute kidney injury (AKI) in critical COVID-19. However, limited data exist to support this. We aim to investigate the differences in renal perfusion, oxygenation and water diffusion using multiparametric magnetic resonance imaging in critically ill COVID-19 patients with and without AKI.

METHODS

A prospective case-control study where patients without prior kidney disease treated in intensive care for respiratory failure due to COVID-19 were examined. Kidney Disease: Improving Global Outcomes Creatinine criteria were used for group allocation. Main comparisons were tested using Mann-Whitney U test.

RESULTS

Nineteen patients were examined, ten with AKI and nine without AKI. Patients with AKI were examined in median 1 [0-2] day after criteria fulfillment. Age and baseline Plasma-Creatinine were similar in both groups. Total renal blood flow was lower in patients with AKI compared with patients without (median 645 quartile range [423-753] vs. 859 [746-920] ml/min, p = 0.037). Regional perfusion was reduced in both cortex (76 [51-112] vs. 146 [123-169] ml/100 g/min, p = 0.015) and medulla (28 [18-47] vs. 47 [38-73] ml/100 g/min, p = 0.03). Renal venous saturation was similar in both groups (72% [64-75] vs. 72% [63-84], ns.), as was regional oxygenation (R₂*) in cortex (17 [16-19] vs. 17 [16-18] 1/s, ns.) and medulla (29 [24-39] vs. 27 [23-29] 1/s, ns.).

CONCLUSIONS

In critically ill COVID-19 patients with AKI, the total, cortical and medullary renal blood flows were reduced compared with similar patients without AKI, whereas no differences in renal oxygenation were demonstrable in this setting. Trial registration ClinicalTrials ID: NCT02765191 , registered May 6 2014 and updated May 7 2020.

Bioinformatics analysis of potential pathogenesis and risk genes of immunoinflammation-promoted renal injury in severe COVID-19

Renal injury secondary to COVID-19 is an important factor for the poor prognosis of COVID-19 patients. The pathogenesis of renal injury caused by aberrant immune inflammatory of COVID-19 remains unclear. In this study, a total of 166 samples from 4 peripheral blood transcriptomic datasets of COVID-19 patients were integrated. By using the weighted gene co-expression network (WGCNA) algorithm, we identified key genes for mild, moderate, and severe COVID-19. Subsequently, taking these genes as input genes, we performed Short Time-series Expression Miner (STEM) analysis in a time consecutive ischemia-reperfusion injury (IRI) -kidney dataset to identify genes associated with renal injury in COVID-19. The results showed that only in severe COVID-19 there exist a small group of genes associated with the progression of renal injury. Gene enrichment analysis revealed that these genes are involved in extensive immune inflammation and cell death-related pathways. A further protein-protein interaction (PPI) network analysis screened 15 PPI-hub genes: ALOX5, CD38, GSF3R, LGR, RPR1, HCK, ITGAX, LYN, MAPK3, NCF4, SELP, SPI1, WAS, TLR2 and TLR4. Single-cell sequencing analysis indicated that PPI-hub genes were mainly distributed in neutrophils, macrophages, and dendritic cells. Intercellular ligand-receptor analysis characterized the activated ligand-receptors between these immune cells and parenchyma cells in depth. And KEGG enrichment analysis revealed that viral protein interaction with cytokine and cytokine receptor, necroptosis, and Toll-like receptor signaling pathway may be potentially essential for immune cell infiltration leading to COVID-19 renal injury. Finally, we validated the expression pattern of PPI-hub genes in an independent data set by random forest. In addition, we found that the high expression of these genes was correlated with a low glomerular filtration rate. Including them as risk genes in lasso regression, we constructed a Nomogram model for predicting severe COVID-19. In conclusion, our study explores the pathogenesis of renal injury promoted by immunoinflammatory in severe COVID-19 and extends the clinical utility of its key genes.

Imaging Techniques: Essential Tools for the Study of SARS-CoV-2 Infection

The world has seen the emergence of a new virus in 2019, SARS-CoV-2, causing the COVID-19 pandemic and millions of deaths worldwide. Microscopy can be much more informative than conventional detection methods such as RT-PCR. This review aims to present the up-to-date microscopy observations in patients, the in vitro studies of the virus and viral proteins and their interaction with their host, discuss the microscopy techniques for detection and study of SARS-CoV-2, and summarize the reagents used for SARS-CoV-2 detection. From basic fluorescence microscopy to high resolution techniques and combined technologies, this article shows the power and the potential of microscopy techniques, especially in the field of virology.

A Prospective Study on Risk Factors for Acute Kidney Injury and All-Cause Mortality in Hospitalized COVID-19 Patients From Tehran (Iran)

Background

Several reports suggested that acute kidney injury (AKI) is a relatively common occurrence in hospitalized COVID-19 patients, but its prevalence is inconsistently reported across different populations. Moreover, it is unknown whether AKI results from a direct infection of the kidney by SARS-CoV-2 or it is a consequence of the physiologic disturbances and therapies used to treat COVID-19. We aimed to estimate the prevalence of AKI since it varies by geographical settings, time periods, and populations studied and to investigate whether clinical information and laboratory findings collected at hospital admission might influence AKI incidence (and mortality) in a particular point in time during hospitalization for COVID-19.

Methods

Herein we conducted a prospective longitudinal study investigating the prevalence of AKI and associated factors in 997 COVID-19 patients admitted to the Baqiyatallah general hospital of Tehran (Iran), collecting both clinical information and several dates (of: birth; hospital admission; AKI onset; ICU admission; hospital discharge; death). In order to examine how the clinical factors influenced AKI incidence and all-cause mortality during hospitalization, survival analysis using the Cox proportional-hazard models was adopted. Two separate multiple Cox regression models were fitted for each outcome (AKI and death).

Results

In this group of hospitalized COVID-19 patients, the prevalence of AKI was 28.5% and the mortality rate was 19.3%. AKI incidence was significantly enhanced by diabetes, hyperkalemia, higher levels of WBC count, and blood urea nitrogen (BUN). COVID-19 patients more likely to die over the course of their hospitalization were those presenting a joint association between ICU admission with either severe COVID-19 or even mild/moderate COVID-19, hypokalemia, and higher levels of BUN, WBC, and LDH measured at hospital admission. Diabetes and comorbidities did not increase the mortality risk among these hospitalized COVID-19 patients.

Conclusions

Since the majority of patients developed AKI after ICU referral and 40% of them were admitted to ICU within 2 days since hospital admission, these patients may have been already in critical clinical conditions at admission, despite being affected by a mild/moderate form of COVID-19, suggesting the need of early monitoring of these patients for the onset of eventual systemic complications.

Clinical characteristics and factors associated with acute kidney injury among patients hospitalized with coronavirus disease: an observational retrospective study

BACKGROUND

Coronavirus disease 19 (COVID-19) is a multisystemic disease with high incidence of acute kidney injury (AKI).

OBJECTIVE

To describe the clinical characteristics and factors associated with AKI among patients hospitalized with COVID-19.

DESIGN AND SETTING

Retrospective cohort conducted at Hospital Civil de Culiacan, Mexico.

METHODS

We included 307 patients hospitalized due to COVID-19. AKI was defined and staged based on serum creatinine levels in accordance with the criteria of the Acute Kidney Injury Network (AKIN). Multivariate logistic regression analysis was used to determine factors associated with AKI.

RESULTS

The patients' age was 56 ± 15 years (64.5% male). The incidence of AKI was 33.6% (n = 103). Overall, 53.4% of patients had community-acquired AKI, and 46.6% had hospital-acquired AKI. Additionally, 15.5% of them presented AKIN stage 1; 34% had AKIN stage 2; and 50.5% had AKIN stage 3. Hemodialysis was required for 10.7% of the patients. The factors associated with AKI were chronic kidney disease (odds ratio, OR: 10.8; P = 0.04), use of norepinephrine (OR: 7.3; P = 0.002), diabetes mellitus (OR: 2.9; P = 0.03), C-reactive protein level (OR: 1.005; P = 0.01) and COVID-19 severity index based on chest tomography (OR: 1.09; statistical trend, P = 0.07). Hospital stay (11 ± 7 days; P < 0.001) and mortality (83.5 versus 31.4%; P < 0.05) were greater among patients with AKI.

CONCLUSION

AKI was a frequent and serious complication in our cohort of patients hospitalized with COVID-19, which was associated with high mortality and long hospital stay.