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Collapsing glomerulopathy is a rare but severe form of glomerular injury that can be accompanying by SLE (systemic lupus erythematosus). The pathogenesis of collapsing glomerulopathy in lupus is not well understood, and the treatment options are limited. The treatment of collapsing glomerulopathy in lupus is challenging. Immunosuppressive therapy with corticosteroids and cytotoxic agents is the mainstay of treatment. However, the response to therapy is often poor, and many patients progress to end-stage renal disease despite treatment. The use of newer agents such as rituximab and belimumab may offer additional options for the treatment of collapsing glomerulopathy in lupus. Further studies are required to better detect the underlying mechanisms of collapsing glomerulopathy in lupus and to develop more effective therapies for this condition. [ABSTRACT FROM AUTHOR]

Collapsing glomerulopathy is a rare and serious disease that is characterized by a rapid deterioration of kidney function and heavy proteinuria. This disease is a variant of focal segmental glomerulosclerosis (FSGS). The disease is more serious than other types of FSGS, with high risks of renal failure and poor prognosis. Collapsing glomerulopathy is often resistant to immunosuppressive therapy and can rapidly result in renal failure, making diagnosing and managing this disease an enormous challenge. [ABSTRACT FROM AUTHOR]

Although a few registry-based studies have shown associations between receiving kidney allografts from Black donors and shorter allograft survival, detailed, large, single-center studies accounting for common confounding factors are lacking. Furthermore, pathologic alterations underlying this potential disparity have not been systematically studied. We performed a retrospective clinical-pathological study of kidney transplant recipients who received kidney allografts from either Black (n = 407) or White (n = 1,494) donors at Columbia University Irving Medical Center from 2005 to 2018, with median follow-up of 4.5 years post-transplantation. Black donor race was independently associated with allograft failure (adjusted HR = 1.34, p = 0.02) and recipients of kidney allografts from Black donors had a higher incidence of collapsing glomerulopathy [7.4% vs. 1.9%, OR = 4.17, p < 0.001]. When causes of allograft failure were examined, only allograft failure following development of collapsing glomerulopathy was more frequent in recipients of allografts from Black donors [15% vs. 5%, OR = 3.16, p = 0.004]. Notably, when patients who developed collapsing glomerulopathy were excluded from analysis, receiving kidney allografts from Black donors was not independently associated with allograft failure (adjusted HR = 1.24, p = 0.10). These findings revealed that, compared with recipients of kidney allografts from White donors, recipients of kidneys from Black donors have modestly shorter allograft survival and a higher probability of developing collapsing glomerulopathy, which negatively impacts allograft outcome. Identification of collapsing glomerulopathy risk factors may help decrease this complication and improve allograft survival, which optimally may reduce racial disparities post-transplantation.

Podocytes are epithelial cells lining the outer surface of the renal glomerular capillaries and they play a pivotal role in maintaining the structural and functional integrity of the glomerular filtration barrier. Podocytes react to injury in various ways and any injury to these highly specialized cells can progress to podocyte dysfunction, resulting in a group of proteinuric renal diseases called podocytopathies. Podocytopathies include a wide spectrum of primary and secondary kidney diseases, including minimal change disease, diffuse mesangial sclerosis, focal segmental glomerulosclerosis, collapsing glomerulopathy, diabetic, membranous and lupus nephropathies. Etiologically, they can be idiopathic, genetic or secondary to infections and drugs, metabolic diseases, hemodynamic factors or associated with various immune and non-immune systemic diseases. This manuscript provides a basic understanding of podocyte structure, causes of podocyte injury, response to the injury and the subsequent progression to podocytopathies. The pathogenesis of these diseases is set around podocytes. The clinical and morphological manifestations, the commonality and heterogeneity of these podocytopathies are also discussed. As our knowledge of podocyte biology improves, so will our treatment avenues with a more podocyte-centric personalized approach.

Collapsing glomerulopathy has been delineated as the most common morphological feature in COVID-19 individuals presenting with rapidly progressive renal failure and massive proteinuria. This condition, also known as COVID-19-associated nephropathy, has a poor prognosis. In COVID-19-related collapsing glomerulopathy, an immune dysfunction-mediated "second hit" to podocytes of African origin with APOL1 risk alleles was suggested. However, further research is still required to clarify this aspect of glomerulopathy. [ABSTRACT FROM AUTHOR]

Abstract Background Acute kidney injury is now recognized as a common complication of coronavirus disease 2019, affecting up to 46% of patients, with acute tubular injury as the most common etiology. Recently, we have seen an increase in cases of collapsing glomerulonephritis in patients with coronavirus disease 2019, also known as coronavirus disease 2019-associated nephropathy. It has been noted to be seen with a higher incidence in African American patients who are carriers of the APOL1 variant allele. Case presentation A 47-year-old African American male with a past medical history of asthma presented to the emergency department with complaints of intermittent chest pain, shortness of breath, and worsening confusion. On admission, he was found to be hemodynamically stable, but labs were significant for elevated creatinine and blood urea nitrogen, signifying acute kidney injury. He was admitted and taken for emergent dialysis. During his hospitalization, he was found to be positive for coronavirus disease 2019. Renal biopsy was done, which showed collapsing glomerulopathy, and the patient continues to require outpatient dialysis after discharge. Conclusion Collapsing glomerulonephritis has emerged as a complication in patients with coronavirus disease 2019. This condition should be particularly suspected in African American patients who present with acute kidney injury, nephrotic-range proteinuria, and who are positive for coronavirus disease 2019. Current treatment options are limited to supportive treatment and renal replacement therapy. More clinical cases and trials are needed to better understand and improve therapeutic outcomes in these patients.

RATIONALE & OBJECTIVE: Kidney biopsy data inform us about pathologic processes associated with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We conducted a multicenter evaluation of kidney biopsy findings in living patients to identify various kidney disease pathology findings in patients with coronavirus disease 2019 (COVID-19) and their association with SARS-CoV-2 infection. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We identified 14 native and 3 transplant kidney biopsies performed for cause in patients with documented recent or concurrent SARS-CoV-2 infection treated at 7 large hospital systems in the United States. OBSERVATIONS: Men and women were equally represented in this case series, with a higher proportion of Black (n=8) and Hispanic (n=5) patients. All 17 patients had SARS-CoV-2 infection confirmed by reverse transcriptase-polymerase chain reaction, but only 3 presented with severe COVID-19 symptoms. Acute kidney injury (n=15) and proteinuria (n=11) were the most common indications for biopsy and these symptoms developed concurrently or within 1 week of COVID-19 symptoms in all patients. Acute tubular injury (n=14), collapsing glomerulopathy (n=7), and endothelial injury/thrombotic microangiopathy (n=6) were the most common histologic findings. 2 of the 3 transplant recipients developed active antibody-mediated rejection weeks after COVID-19. 8 patients required dialysis, but others improved with conservative management. LIMITATIONS: Small study size and short clinical follow-up. CONCLUSIONS: Cases of even symptomatically mild COVID-19 were accompanied by acute kidney injury and/or heavy proteinuria that prompted a diagnostic kidney biopsy. Although acute tubular injury was seen among most of them, uncommon pathology such as collapsing glomerulopathy and acute endothelial injury were detected, and most of these patients progressed to irreversible kidney injury and dialysis.

Collapsing glomerulopathy has been delineated as the most common morphological feature in COVID-19 individuals presenting with rapidly progressive renal failure and massive proteinuria. This condition, also known as COVID-19-associated nephropathy, has a poor prognosis. In COVID-19-related collapsing glomerulopathy, an immune dysfunction-mediated "second hit" to podocytes of African origin with APOL1 risk alleles was suggested. However, further research is still required to clarify this aspect of glomerulopathy.

Abstract Background Collapsing glomerulopathy, characterized by marked hypertrophy and hyperplasia of the podocytes with eventual collapse of the glomerular tuft, is an important cause of end-stage renal disease. Among the many causes of collapsing glomerulopathy, autoimmune diseases, such as systemic lupus erythematosus, have been implicated. There are also rare reports of adult-onset Still’s disease, an autoinflammatory condition characterized by fever, rash, and inflammatory arthritis being associated with collapsing glomerulopathy. Case presentation Herein, we present a review of three published cases, and present a new case of a 15-year-old African American female patient with collapsing glomerulopathy who was diagnosed with adult-onset Still’s disease 12 years later when she presented with fevers, arthralgias, sore throat, lymphadenopathy, hepatocellular injury, and elevated serum ferritin. Her collapsing glomerulopathy was initially well controlled following induction therapy with cyclosporine and prednisone and maintenance therapy with losartan. However, after developing adult-onset Still’s disease, she had multiple flare-ups despite various immunosuppressive therapies and developed worsening renal function, eventually progressing to end-stage renal disease. Conclusions Our case-based review highlights a rare but important association between adult-onset Still’s disease and collapsing glomerulopathy, and postulates a possible pathophysiological link.

Background: Acute kidney injury is now recognized as a common complication of coronavirus disease 2019, affecting up to 46% of patients, with acute tubular injury as the most common etiology. Recently, we have seen an increase in cases of collapsing glomerulonephritis in patients with coronavirus disease 2019, also known as coronavirus disease 2019-associated nephropathy. It has been noted to be seen with a higher incidence in African American patients who are carriers of the APOL1 variant allele. Case presentation: A 47-year-old African American male with a past medical history of asthma presented to the emergency department with complaints of intermittent chest pain, shortness of breath, and worsening confusion. On admission, he was found to be hemodynamically stable, but labs were significant for elevated creatinine and blood urea nitrogen, signifying acute kidney injury. He was admitted and taken for emergent dialysis. During his hospitalization, he was found to be positive for coronavirus disease 2019. Renal biopsy was done, which showed collapsing glomerulopathy, and the patient continues to require outpatient dialysis after discharge. Conclusion: Collapsing glomerulonephritis has emerged as a complication in patients with coronavirus disease 2019. This condition should be particularly suspected in African American patients who present with acute kidney injury, nephrotic-range proteinuria, and who are positive for coronavirus disease 2019. Current treatment options are limited to supportive treatment and renal replacement therapy. More clinical cases and trials are needed to better understand and improve therapeutic outcomes in these patients. [ABSTRACT FROM AUTHOR]

World kidney day is an international campaign focused on bringing awareness to kidney health throughout the world and reducing the incidence of renal disease and its related medical complications. This mini-review sought to take a short look on the renal impact of SARS-CoV-2, with a particular focus on post-COVID-19 nephropathy as a new dilemma in the era of nephrology, which can be a new concern for nephrologists that requires more attention and particular strategies.

Hospitalized COVID-19 patients often develop acute kidney injury (AKI), leading to increased mortality. In order to improve patients’ survival rate, it is important to understand the pathophysiology mechanism of AKI. In this brief review, we highlight the most important elements of the etiology and pathophysiology of COVID-19 associated AKI. Acute tubular injury seems to be more frequent than prerenal azotemia in COVID-19 patients and collapsing glomerulopathy is the most encountered form of glomerular disease. Another important role in acute kidney injury seems to play immune cell infiltration, inflammation, endothelial injury and microvascular thrombi. Renin-angiotensin-aldosterone system is also important in the pathophysiology of COVID-19 associated AKI.

Background: Collapsing glomerulopathy, characterized by marked hypertrophy and hyperplasia of the podocytes with eventual collapse of the glomerular tuft, is an important cause of end-stage renal disease. Among the many causes of collapsing glomerulopathy, autoimmune diseases, such as systemic lupus erythematosus, have been implicated. There are also rare reports of adult-onset Still's disease, an autoinflammatory condition characterized by fever, rash, and inflammatory arthritis being associated with collapsing glomerulopathy.Case Presentation: Herein, we present a review of three published cases, and present a new case of a 15-year-old African American female patient with collapsing glomerulopathy who was diagnosed with adult-onset Still's disease 12 years later when she presented with fevers, arthralgias, sore throat, lymphadenopathy, hepatocellular injury, and elevated serum ferritin. Her collapsing glomerulopathy was initially well controlled following induction therapy with cyclosporine and prednisone and maintenance therapy with losartan. However, after developing adult-onset Still's disease, she had multiple flare-ups despite various immunosuppressive therapies and developed worsening renal function, eventually progressing to end-stage renal disease.Conclusions: Our case-based review highlights a rare but important association between adult-onset Still's disease and collapsing glomerulopathy, and postulates a possible pathophysiological link. [ABSTRACT FROM AUTHOR]

Collapsing glomerulopathy (CG) or collapsing focal segmental glomerulosclerosis (cFSGS) is an aggressive disease with a high tendency of progression to end-stage renal disease due to common resistance to conventional immunosuppressants. Rituximab (RTX), a monoclonal antibody against CD20 B cells, showed some benefit in the treatment of CG. We are reporting about female patients with an idiopathic form of CG presenting with nephrotic syndrome (NS) and renal insufficiency resistant to several immunosuppressive agents such as steroids (ST), calcineurin inhibitors (CNI), and cyclophosphamide (CYC). This multidrug-resistant disease responded to RTX with complete remission. Forty-four months after initial RTX administration, a relapse of CG with severe NS and acute renal insufficiency occurred. Repeated application of RTX led to complete remission again. To the best of our knowledge, we are reporting the first case of the relapsing multidrug-resistant form of CG, which responded to RTX. Current data about the treatment of CG with RTX is lacking and is based on rare case reports and small case series. Thus, our report can contribute to determining the role of RTX in the treatment of CG. [ABSTRACT FROM AUTHOR]

Purpose: A previous immunofluorescent study suggests that, in collapsing glomerulopathy, most hyperplastic podocytes that stained positively for a progenitor cell marker CD133 are derived from CD133 + parietal epithelial cells. In pathology practice, not all renal biopsies with collapsing glomerulopathy show the typical morphologic features for this entity, which include florid podocyte hyperplasia, collapsing glomerular capillary loops, and cystic tubular dilation. This study was made to determine if CD133 staining using an immunohistochemical method can be used to confirm hyperplastic podocytes and identify extensive acute tubular injury in collapsing glomerulopathy. Methods: Twenty-one collapsing glomerulopathy biopsies were stained for CD133 and compared with 15 biopsies with focal segmental glomerulosclerosis, not otherwise specified (FSGS). Results: All patients with collapsing glomerulopathy were of African American descent with prominent renal failure and nephrotic range proteinuria. In contrast, the FSGS group consisted of patients from a variety of ethnic backgrounds with nephrotic range proteinuria but relatively low serum creatinine. The striking finding was that all collapsing glomerulopathy cases showed positive CD133 staining in the clusters of hyperplastic podocytes. There was significantly higher CD133-positive staining rate for hyperplastic podocytes (38%) in the glomeruli of the collapsing glomerulopathy group when compared to small clusters of hyperplastic podocytes in the FSGS group (8%). In addition, when compared to the relatively weak CD133 staining in the proximal tubules of the FSGS group, the proximal tubules of the collapsing glomerulopathy group all showed diffuse and strong CD133 staining as a feature of severe acute tubular injury, which corresponded to the high serum creatinine levels in these patients. Conclusion: Our data indicate that the combination of the distinctive mosaic CD133 staining in hyperplastic podocytes and the diffuse tubular CD133 staining is helpful in supporting a diagnosis of collapsing glomerulopathy. [ABSTRACT FROM AUTHOR]

Recent case reports suggest that coronavirus disease 2019 (COVID-19) is associated with collapsing glomerulopathy in African Americans with apolipoprotein L1 gene (APOL1) risk alleles; however, it is unclear whether disease pathogenesis is similar to HIV-associated nephropathy. RNA sequencing analysis of a kidney biopsy specimen from a patient with COVID-19–associated collapsing glomerulopathy and APOL1 risk alleles (G1/G1) revealed similar levels of APOL1 and angiotensin-converting enzyme 2 (ACE2) messenger RNA transcripts as compared with 12 control kidney samples downloaded from the GTEx (Genotype-Tissue Expression) Portal. Whole-genome sequencing of the COVID-19–associated collapsing glomerulopathy kidney sample identified 4 indel gene variants, 3 of which are of unknown significance with respect to chronic kidney disease and/or focal segmental glomerulosclerosis. Molecular profiling of the kidney demonstrated activation of COVID-19–associated cell injury pathways such as inflammation and coagulation. Evidence for direct severe acute respiratory syndrome coronavirus 2 infection of kidney cells was lacking, which is consistent with the findings of several recent studies. Interestingly, immunostaining of kidney biopsy sections revealed increased expression of phospho-STAT3 (signal transducer and activator of transcription 3) in both COVID-19–associated collapsing glomerulopathy and HIV-associated nephropathy as compared with control kidney tissue. Importantly, interleukin 6–induced activation of STAT3 may be a targetable mechanism driving COVID-19–associated acute kidney injury.

We describe a kidney transplant recipient who presented 7 months after transplantation with nephrotic proteinuria and graft dysfunction, which on biopsy revealed two concomitant lesions: de novo membranous and collapsing glomerulopathies. While the index episode responded favorably to plasmapheresis and rituximab, repeat evaluation 4 months later showed an evolution of acute antibody-mediated rejection, along with the remnant pathologies. [ABSTRACT FROM AUTHOR]

Abstract Background Coronavirus disease-2019 (COVID-19) is an ongoing pandemic which has affected over 12 million people across the globe. Manifestations in different organs systems are being reported regularly. Renal biopsy findings in hospitalized COVID-19 patients presenting solely with acute kidney injury (AKI) have recently been described in published literature in few case reports. The findings include diffuse acute tubular injury (ATI) along with the glomerular lesion of collapsing glomerulopathy (CG). However, nephrotic syndrome as the presenting complaint of COVID-19 has not been reported widely, neither has any other glomerular lesion other than CG. Case presentation We describe the kidney biopsy findings of two patients who had recent diagnoses of COVID-19 and presented with new-onset nephrotic syndrome. Renal biopsy in both patients showed ATI (as in previous reports) and distinct glomerular findings on light microscopy – that of minimal change disease (MCD) initially in one patient followed by CG in a subsequent biopsy and CG at the outset in the other patient. The electron microscopic findings in both patients were that of severe podocytopathy (diffuse and severe podocyte foot process effacement). Conclusion Our cases highlight a novel clinical presentation of COVID-19 renal disease, not described before, that of new-onset nephrotic syndrome. While all published case reports describe CG as the glomerular pathology, we describe a non-CG pathology (MCD) in one of our cases, thereby adding to the repertoire of renal pathology described in association with COVID-19 patients. However, the exact mechanism by which podocyte injury or podocytopathy occurs in all such cases is still unknown. Optimal treatment options for these patients also remains unknown at this time.

Podocytopathies are a group of proteinuric glomerular disorders driven by primary podocyte injury that are associated with a set of lesion patterns observed on kidney biopsy, i.e., minimal changes, focal segmental glomerulosclerosis, diffuse mesangial sclerosis and collapsing glomerulopathy. These unspecific lesion patterns have long been considered as independent disease entities. By contrast, recent evidence from genetics and experimental studies demonstrated that they represent signs of repeated injury and repair attempts. These ongoing processes depend on the type, length, and severity of podocyte injury, as well as on the ability of parietal epithelial cells to drive repair. In this review, we discuss the main pathology patterns of podocytopathies with a focus on the cellular and molecular response of podocytes and parietal epithelial cells.

Podocytes are epithelial cells lining the outer surface of the renal glomerular capillaries and they play a pivotal role in maintaining the structural and functional integrity of the glomerular filtration barrier. Podocytes react to injury in various ways and any injury to these highly specialized cells can progress to podocyte dysfunction, resulting in a group of proteinuric renal diseases called podocytopathies. Podocytopathies include a wide spectrum of primary and secondary kidney diseases, including minimal change disease, diffuse mesangial sclerosis, focal segmental glomerulosclerosis, collapsing glomerulopathy, diabetic, membranous and lupus nephropathies. Etiologically, they can be idiopathic, genetic or secondary to infections and drugs, metabolic diseases, hemodynamic factors or associated with various immune and non-immune systemic diseases. This manuscript provides a basic understanding of podocyte structure, causes of podocyte injury, response to the injury and the subsequent progression to podocytopathies. The pathogenesis of these diseases is set around podocytes. The clinical and morphological manifestations, the commonality and heterogeneity of these podocytopathies are also discussed. As our knowledge of podocyte biology improves, so will our treatment avenues with a more podocyte-centric personalized approach., Competing Interests: The author declares no conflict of interest., (© 2024 The Author(s). Published by IMR Press.)

Collapsing glomerulopathy (CG) is a pattern of kidney injury characterized by segmental or global collapse of the glomerular tuft associated with overlying epithelial cell hyperplasia. Although CG may be idiopathic, a wide range of etiologies have been identified that can lead to this pattern of injury. Recent advances have highlighted the role of inflammatory and interferon signaling pathways and upregulation of apolipoprotein L1 (APOL1) within podocytes in those carrying a high-risk APOL1 genotype. In this review, we describe the etiology, pathogenesis, pathology, and clinical course of CG, focusing on nonviral etiologies. We also describe current treatments and explore potential therapeutic options targeting interferon/APOL1 pathways in CG., (Copyright © 2024 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

The COVID-19 era has been a reminder to clinicians around the world of the important role that viral infections play in promoting glomerular disease. Several viral infections including human immunodeficiency virus (HIV), severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, cytomegalovirus, and parvovirus B19 can cause podocyte injury and present with a collapsing glomerulopathy (CG) variant of focal segmental glomerulosclerosis or minimal change disease. CG associated with COVID-19 has been termed COVID-19-associated nephropathy due to its striking resemblance to HIV-associated nephropathy. Host susceptibility is a major determinant of viral infection-associated CG, and the presence of two APOL1 risk variants explains most of the racial predilection to viral-associated CG observed in individuals of African ancestry. Interactions between APOL1 risk variants, viral genes, and the systemic inflammatory response to viral infection all contribute to kidney injury. This review will summarize our current knowledge of viral infection-associated CG, focusing primarily on the clinical presentation, histological features, mechanisms, and disease course of HIV-associated nephropathy and COVID-19-associated nephropathy., (Copyright © 2023 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

A 39-year-old woman presented with inflammatory polyarthritis, low-grade fever, progressive pedal edema, and frothy urination of three weeks duration. She had nephrotic range proteinuria and elevated creatinine. Kidney biopsy showed collapse of capillary tuft in the glomeruli and proliferation, hyperplasia, and hypertrophy of the overlying podocytes suggestive of collapsing glomerulopathy. Histology of the cervical lymph node showed necrotizing granulomatous inflammation suggestive of tuberculosis. With all other possible causes of polyarthritis ruled out, a diagnosis of Poncet's disease--a form of polyarthritis observed in patients suffering from an active form of extrapulmonary tuberculosis (TB)--was considered. Association between TB lymphadenitis and collapsing glomerulopathy (CG) is very rare, and the patient had partial remission of the disease after being started on anti-tuberculosis therapy (ATT) along with steroids. [ABSTRACT FROM AUTHOR]

Hospitalized COVID-19 patients often develop acute kidney injury (AKI), leading to increased mortality. In order to improve patients’ survival rate, it is important to understand the pathophysiology mechanism of AKI. In this brief review, we highlight the most important elements of the etiology and pathophysiology of COVID-19 associated AKI. Acute tubular injury seems to be more frequent than prerenal azotemia in COVID-19 patients and collapsing glomerulopathy is the most encountered form of glomerular disease. Another important role in acute kidney injury seems to play immune cell infiltration, inflammation, endothelial injury and microvascular thrombi. Renin-angiotensin-aldosterone system is also important in the pathophysiology of COVID-19 associated AKI. [ABSTRACT FROM AUTHOR]

Background The coronavirus disease 2019 (COVID-19) may be associated with kidney injury, which may impact patient's prognosis. Methods We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury (AKI) and/or proteinuria and underwent a kidney biopsy in Paris and its metropolitan area. Results Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between 8 March and 19 May 2020 were included. The median age was 63 years (interquartile range 52–69). Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney disease (25.5%), cardiac diseases (38.6%) and respiratory diseases (27.3%). Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%) and diarrhoea (23.4%). Almost all patients developed AKI (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy (CG) and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while 8 (17%) had an alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and CG was only observed in patients harbouring a combination of APOL1 risk variants. At the last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 had died. Conclusions This study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants. [ABSTRACT FROM AUTHOR]

Introduction. Focal segmental glomerulosclerosis (FSGS) is defined as an increase in the mesangial matrix in some glomeruli with obliteration of capillary lumens, sclerosis, hyalinosis, foam cells, and adhesions to the Bowman's capsule. Collapsing glomerulopathy is a morphologic variant of focal segmental glomerulosclerosis (FSGS) characterized by segmental and global collapse of the glomerular capillaries, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. Actually secondary collapsing glomerulopathy is a heterogeneous group including numerous causes: viruses, toxins and drugs such as heroin and pamidronate. Case reports. We report on two cases with glomerular disease after COVID-19 infection. The first patient, 53 years old male, with nephrotic syndrome and histopathologic features of glomerular capillary collapse. He was admitted in our department with nephrotic syndrome and renal failure. Several months ago, he had COVID-19 infection and was treated for COVID-19 pneumonia, but he had not symptoms for any renal disease. In following months, the patients manifested symptoms such as nausea, dysuria and light malleolar edema. Laboratory findings presented increased values of BUN 27mmol/l, creatinine 453 µmol/l, with proteinuria 4,6 g/24h. In order to identify the cause for these results, renal biopsy was performed with diagnose of collapsing glomerulopathy. The patient was followed up for a period of 6 months and treated with corticosteroid therapy. The values for creatinine were decreased to 195 µmol/l, with proteinuria 1 g/24h. After that the patient was stable, but with slowly increasing values for creatinine up to 242µmol/l and proteinuria 0,61 g/24h, for a period of the next several months. Second case was a patient 58 years old, male with pulmo- renal syndrome, with bilateral pneumonia and acute kidney injury. COVID 19 infection was established with BUN 36 mmol/l and serum creatinine up to 586 µmol/l. Several weeks the patient was treated with hemodialysis. After that the patient was stable, the values for BUN and serum creatinine were still higher but without necessity for dialysis treatment. Proteinuria of 1,98 g/24hours still remained and renal biopsy was performed. Focal segmental glomerulosclerosis was diagnosed. The follow up in next several months included therapy with corticosteroids, after that with cyclosporin, with effect on improved kidney function with BUN 14 mmol/l, creatinine 156 µmol/l and values for proteinuria of 0,96 g/24hours. Conclusion. SARS-CoV-2 associated renal disease seems to have different outcome and follow up despite the treatment. Renal biopsy may be crucial along with the molecular testing for COVID 19. [ABSTRACT FROM AUTHOR]

Increasing awareness regarding CKD and self-care during COVID-19 pandemic has become the most important aspect for the nephrologists. Hence it is appropriate that the theme of the forthcoming World Kidney Day on 11 March 2021 should be "Strive for kidney health for everyone during COVID-19"

Kidney is one of the most predominantly organs affected by coronavirus disease 2019 (COVID-19) after the respiratory and immune systems. Among the renal parenchymal components, the tubulointerstitial compartment is presumed to be the prime target of injury in COVID-19. The main mechanism of renal tubular damage by COVID-19 is considered to be indirect, i.e., cytokine-mediated injury. A proportion of infected individuals mount a strong inflammatory response to the virus by an exaggerated immune response of the body, namely cytokine storm. Sudden and massive release of cytokines may lead to serious systemic hyper-inflammation and renal tubular injury and inflammation resulting in acute renal failure. In addition, a number of cases of glomerulopathies, particularly collapsing glomerulopathy (CG) have been reported, predominantly in people of African ancestry, as a rare form of kidney involvement by SARS-CoV-2 that may originate from the background genetic susceptibility in this population complicated by the second hit of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, either directly or indirectly. It is noteworthy that renal injury in COVID-19 could be severe in individuals of African origin due to the aforementioned genetic susceptibility, especially the presence of high-risk apolipoprotein L1 (APOL1) genotypes. Although the exact mechanism of kidney injury by SARS-CoV-2 is as yet unknown, multiple mechanisms are likely involved in renal damage caused by this virus. This review was aimed to summarize the salient points of pathogenesis of kidney injury, particularly glomerular injury in COVID-19 disease in the light of published data. A clear understanding of these is imperative for the proper management of these cases. For this review, a search was made of Google Scholar, Web of Science, Scopus, EBSCO and PubMed for finding English language articles related to COVID-19, kidney injury and glomerulopathy. From the information given in finally selected papers, the key aspects regarding glomerular involvement in COVID-19 were drawn out and are presented in this descriptive review.

Kidney is one of the most common organs affected by coronavirus disease 2019 (COVID-19) after the respiratory and immune systems. Among the renal parenchymal components, the tubulointerstitial compartment is presumed to be the prime target of injury in COVID-19. The main mechanism of renal tubular damage by COVID-19 is considered to be indirect, i.e., cytokine-mediated injury. A proportion of infected individuals mount a strong inflammatory response to the virus by an exaggerated immune response of the body, namely cytokine storm. Sudden and massive release of cytokines may lead to serious systemic hyper-inflammation and renal tubular injury and inflammation resulting in acute renal failure. In addition, a number of cases of glomerulopathies, particularly collapsing glomerulopathy (CG) have been reported, predominantly in people of African ancestry, as a rare form of kidney involvement by SARS-CoV-2 that may originate from the background genetic susceptibility in this population complicated by the second hit of SARS-CoV-2 infection, either directly or indirectly. It is noteworthy that renal injury in COVID-19 could be severe in individuals of African origin due to the aforementioned genetic susceptibility, especially the presence of high-risk apolipoprotein L1 (APOL1) genotypes. Although the exact mechanism of kidney injury by SARS-CoV-2 is as yet unknown, multiple mechanisms are likely involved in renal damage caused by this virus. This review was aimed to summarize the salient points of pathogenesis of kidney injury, particularly glomerular injury in COVID-19 disease in the light of published data. A clear understanding of these is imperative for the proper management of these cases. For this review, a search was made of Google Scholar, Web of Science, Scopus, EBSCO and PubMed for finding English language articles related to COVID-19, kidney injury and glomerulopathy. From the information given in finally selected papers, the key aspects regarding glomerular involvement in COVID-19 were drawn out and are presented in this descriptive review. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is common among hospitalized patients with coronavirus disease 2019 (COVID-19), with the occurrence of AKI ranging from 0.5% to 80%. An improved knowledge of the pathology of AKI in COVID-19 is crucial to mitigate and manage AKI and to improve the survival of patients who develop AKI during COVID-19. In this review, we summarize the published cases and case series of various kidney pathologies seen with COVID-19. Both live kidney biopsies and autopsy series suggest acute tubular injury as the most commonly encountered pathology. Collapsing glomerulopathy and thrombotic microangiopathy are other encountered pathologies noted in both live and autopsy tissues. Other rare findings such as anti-neutrophil cytoplasmic antibody vasculitis, anti-glomerular basement membrane disease and podocytopathies have been reported. Although direct viral infection of the kidney is possible, it is certainly not a common or even widespread finding reported at the time of this writing (November 2020). [ABSTRACT FROM AUTHOR]

Although a few registry-based studies have shown associations between receiving kidney allografts from Black donors and shorter allograft survival, detailed, large, single-center studies accounting for common confounding factors are lacking. Furthermore, pathologic alterations underlying this potential disparity have not been systematically studied. We performed a retrospective clinical-pathological study of kidney transplant recipients who received kidney allografts from either Black ( n  = 407) or White ( n  = 1,494) donors at Columbia University Irving Medical Center from 2005 to 2018, with median follow-up of 4.5 years post-transplantation. Black donor race was independently associated with allograft failure (adjusted HR = 1.34, p = 0.02) and recipients of kidney allografts from Black donors had a higher incidence of collapsing glomerulopathy [7.4% vs. 1.9%, OR = 4.17, p < 0.001]. When causes of allograft failure were examined, only allograft failure following development of collapsing glomerulopathy was more frequent in recipients of allografts from Black donors [15% vs. 5%, OR = 3.16, p  = 0.004]. Notably, when patients who developed collapsing glomerulopathy were excluded from analysis, receiving kidney allografts from Black donors was not independently associated with allograft failure (adjusted HR = 1.24, p  = 0.10). These findings revealed that, compared with recipients of kidney allografts from White donors, recipients of kidneys from Black donors have modestly shorter allograft survival and a higher probability of developing collapsing glomerulopathy, which negatively impacts allograft outcome. Identification of collapsing glomerulopathy risk factors may help decrease this complication and improve allograft survival, which optimally may reduce racial disparities post-transplantation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 DiFranza, Daniel, Serban, Thomas, Santoriello, Ratner, D’Agati, Vasilescu, Husain and Batal.)

Collapsing glomerulopathy (CG) is most often associated with fast progression to kidney failure with an incidence apparently higher in Brazil than in other countries. However, the reason for this occurrence is unknown. To better understand this, we performed an integrated analysis of clinical, histological, therapeutic, causative genetic and genetic ancestry data in a highly genetically admixed cohort of 70 children and adult patients with idiopathic CG (ICG). The disease onset occurred at 23 (interquartile range: 17-31) years and approximately half of patients progressed to chronic kidney disease requiring kidney replacement therapy (CKD-KRT) 36 months after diagnosis. Causative genetic bases, assessed by targeted-gene panel or whole-exome sequencing, were identified in 58.6% of patients. Among these cases, 80.5% harbored APOL1 high-risk genotypes (HRG) and 19.5% causative Mendelian variants (MV). Self-reported non-White patients more frequently had HRG. MV was an independent risk factor for progression to CKD-KRT by 36 months and the end of follow-up, while remission was an independent protective factor. All patients with HRG manifested CG at 9-44 years of age, whereas in those with APOL1 low-risk genotype, the disease arose throughout life. HRGs were associated with higher proportion of African genetic ancestry. Novel causative MVs were identified in COL4A5, COQ2 and PLCE1 and previously described causative MVs were identified in MYH9, TRPC6, COQ2, COL4A3 and TTC21B. Three patients displayed HRG combined with a variant of uncertain significance (ITGB4, LAMA5 or PTPRO). MVs were associated with worse kidney prognosis. Thus, our data reveal that the genetic status plays a major role in ICG pathogenesis, accounting for more than half of cases in a highly admixed Brazilian population., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Nephrotic range proteinuria has been reported during the course of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and coronavirus disease (COVID‐19). However, the pathological mechanisms underlying this manifestation are unknown. In this article, we present two cases of collapsing glomerulopathy (CG) associated with acute tubular necrosis during the course of COVID‐19, and review the literature for similar reports. In our two cases, as in the 14 cases reported so far, the patients were of African ancestry. The 14 patients assessed had an APOL1 high‐risk genotype. At the end of the reported period, two patients had died and five patients were still requiring dialysis. The 16 cases detailed in the present report strongly argue in favour of a causal link between SARS‐CoV‐2 infection and the occurrence of CG in patients homozygous for APOL1 high‐risk genotype for which the term COVID‐associated nephropathy (COVIDAN) can be put forward. [ABSTRACT FROM AUTHOR]

Kidney involvement appears to be frequent in coronavirus disease 2019 (COVID-19). Despite this, information concerning renal involvement in COVID-19 is still scarce. Several mechanisms appear to be involved in the complex relationship between the virus and the kidney. Also, different morphological patterns have been described in the kidneys of patients with COVID-19. For some authors, however, this association may be just a coincidence. To investigate this issue, we propose assessing renal morphology associated with COVID-19 at the renal pathology reference center of federal university hospitals in Brazil. Data will come from a consortium involving 17 federal university hospitals belonging to Empresa Brasileira de Serviços Hospitalares (EBSERH) network, as well as some state hospitals and an autopsy center. All biopsies will be sent to the referral center for renal pathology of the EBSERH network. The data will include patients who had coronavirus disease, both alive and deceased, with or without pre-existing kidney disease. Kidney biopsies will be analyzed by light, fluorescence, and electron microscopy. Furthermore, immunohistochemical (IHC) staining for various inflammatory cells (i.e., cells expressing CD3, CD20, CD4, CD8, CD138, CD68, and CD57) as well as angiotensin-converting enzyme 2 (ACE2) will be performed on paraffinized tissue sections. In addition to ultrastructural assays, in situ hybridization (ISH), IHC and reverse transcription-polymerase chain reaction (RT-PCR) will be used to detect Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) in renal tissue. For the patients diagnosed with Collapsing Glomerulopathy, peripheral blood will be collected for apolipoprotein L-1 (APOL1) genotyping. For patients with thrombotic microangiopathy, thrombospondin type 1 motif, member 13 (ADAMTS13), antiphospholipid, and complement panel will be performed. The setting of this study is Brazil, which is second behind the United States in highest confirmed cases and deaths. With this complete approach, we hope to help define the spectrum and impact, whether immediate or long-term, of kidney injury caused by SARS-CoV-2.

Background: Coronavirus disease-2019 (COVID-19) is an ongoing pandemic which has affected over 12 million people across the globe. Manifestations in different organs systems are being reported regularly. Renal biopsy findings in hospitalized COVID-19 patients presenting solely with acute kidney injury (AKI) have recently been described in published literature in few case reports. The findings include diffuse acute tubular injury (ATI) along with the glomerular lesion of collapsing glomerulopathy (CG). However, nephrotic syndrome as the presenting complaint of COVID-19 has not been reported widely, neither has any other glomerular lesion other than CG.Case Presentation: We describe the kidney biopsy findings of two patients who had recent diagnoses of COVID-19 and presented with new-onset nephrotic syndrome. Renal biopsy in both patients showed ATI (as in previous reports) and distinct glomerular findings on light microscopy - that of minimal change disease (MCD) initially in one patient followed by CG in a subsequent biopsy and CG at the outset in the other patient. The electron microscopic findings in both patients were that of severe podocytopathy (diffuse and severe podocyte foot process effacement).Conclusion: Our cases highlight a novel clinical presentation of COVID-19 renal disease, not described before, that of new-onset nephrotic syndrome. While all published case reports describe CG as the glomerular pathology, we describe a non-CG pathology (MCD) in one of our cases, thereby adding to the repertoire of renal pathology described in association with COVID-19 patients. However, the exact mechanism by which podocyte injury or podocytopathy occurs in all such cases is still unknown. Optimal treatment options for these patients also remains unknown at this time. [ABSTRACT FROM AUTHOR]

Among patients hospitalized for novel coronavirus disease (COVID-19), between 10 and 14% develop an acute kidney injury and around half display marked proteinuria and haematuria. Post-mortem analyses of COVID-19 kidney tissue suggest that renal tubular cells and podocytes are affected. Here we report two cases of collapsing glomerulopathy and tubulointerstitial lesions in living COVID-19 patients. Despite our use of sensitive reverse transcription polymerase chain reaction techniques in this study, we failed to detect the virus in blood, urine and kidney tissues. Our observations suggest that these kidney lesions are probably not due to direct infection of the kidney by severe acute respiratory syndrome coronavirus 2. [ABSTRACT FROM AUTHOR]

Collapsing glomerulopathy (CG) is a rare glomerular disease and its familial form is even rarer. CG and non-collapsing forms of focal segmental glomerulosclerosis may both be caused by pathogenic variants in the same genes, but there is less information on genetics of the former disease. We hypothesized that different hits (viral infection and genetic variants) may be involved in the development of a familial CG here described. We performed renal and etiological routine evaluation, PVB19 serology, genetic tests including whole-exome analysis and dosage of serum thrombomodulin (THBD) in two siblings with CG, one healthy sister, and their mother. The THBD gene variant p.A43T in homozygosity was identified in the proband and her affected brother, both with CG. The same mutation was identified in their mother in heterozygosity. THBD levels were elevated in the serum of both affected siblings. They also had PVB19 positive serology and the G1 high-risk apolipoprotein L1 (APOL1) alleles in homozygosity. Their healthy sister had no PVB19-positive serology and no THBD nor APOL1 gene variants. In this case of familial CG, THBD, and APOL1 gene variants, and a previous PVB19 infection may be associated with the development of CG in a multihit process. In addition, the p.A43T THBD variant, identified in the affected siblings, has never been previously described in homozygosis, pointing to a likely autosomal recessive CG trait caused by this gene mutation., (© 2024 S. Karger AG, Basel.)

Diabetic nephropathy (DN) is characterized by gradually progressive renal failure and proteinuria. Various types of nondiabetic kidney diseases may superimpose on DN, and affect the natural course, prognosis, and management. Collapsing glomerulopathy (CG) is a form of glomerular proliferative injury, characterized by rapid progression and associated with poor prognosis. CG may be idiopathic or secondary to other causes, and it has also been described with other forms of glomerular diseases. The association of CG with DN has not been reported widely. We report on a patient with DN who has undergone renal biopsy due to massive proteinuria and rapid loss of renal function. Renal biopsy was suggestive of CG superimposed on DN. He was treated conservatively, however, progressed to end-stage renal disease rapidly. [ABSTRACT FROM AUTHOR]

Patients with collapsing glomerulopathy (CG) have marked proteinuria that rapidly progresses to chronic renal failure. In this study, we investigated if the nephropathy produced in a rat model by the injection of serum from CG patients induced alterations in fatty acid (FA) metabolism. Twenty-four female Sprague-Dawley rats were divided into four groups of six rats each: Group I, control rats (C); Group II, rats that received injections of 1 mL of 0.9% NaCl saline solution (SS); Group III, rats injected with 25 mg/mL of serum from healthy subjects (HS); and Group IV, rats injected with 25 mg/mL of serum from CG patients. In all groups, the systolic blood pressure (SBP), proteinuria, creatinine clearance (CC), cholesterol and total FA composition in the kidney and serum were evaluated. The administration of serum from CG patients to rats induced glomerular collapse, proteinuria, reduced CC and elevated SBP (p ≤ 0.01) in comparison with the C, SS and HS rats. The FA composition of the serum of rats that received the CG serum showed an increase in palmitic acid (PA) and a decrease in arachidonic acid (AA) when compared to serum from HS (p ≤ 0.02). In rats receiving the CG serum, there was also a decrease in the AA in the kidney but there was an increase in the PA in the serum and kidney (p ≤ 0.01). These results suggest that the administration of serum from CG patients to rats induces alterations in FA metabolism including changes in PA and in AA, which are precursors for the biosynthesis of the prostaglandins that are involved in the elevation of SBP and in renal injury. These changes may contribute to collapsing glomerulopathy disease.

Human parvovirus B19 infection causes a variety of glomerular diseases such as post‐infectious acute glomerulonephritis and collapsing glomerulopathy. Although each of these appears independently, it has not been fully determined why parvovirus B19 provokes such a variety of different glomerular phenotypes. Here, we report a 68‐year‐old Japanese man who showed endocapillary proliferative glomerulonephritis admixed with podocytopathy in association with parvovirus B19 infection. The patient showed acute onset of heavy proteinuria, microscopic hematuria and kidney dysfunction with arthralgia and oliguria after close contact with a person suffering from erythema infectiosum. In the kidney biopsy specimen, glomeruli revealed diffuse and global endocapillary infiltration of inflammatory cells, with some also showing tuft collapse with aberrant vacuolation, swelling, and hyperplasia of glomerular epithelial cells. Immunofluorescence revealed dense granular C3 deposition that resembled the “starry sky pattern”. Intravenous glucocorticoid pulse therapy followed by oral prednisolone and cyclosporine combination therapy resulted in considerable amelioration of the kidney dysfunction and urinary abnormalities. The present case reveals that parvovirus B19 infection can induce different glomerular phenotypes even in the same kidney structure. This finding may provide hints useful for the further elucidation of the pathogenesis of parvovirus B19‐induced glomerular lesions. [ABSTRACT FROM AUTHOR]