AKI and Collapsing Glomerulopathy Associated with COVID-19 and APOL 1 High-Risk Genotype.

BACKGROUND: Kidney involvement is a feature of COVID-19 and it can be severe in Black patients. Previous research linked increased susceptibility to collapsing glomerulopathy, including in patients with HIV-associated nephropathy, to apo L1 (APOL1) variants that are more common in those of African descent. METHODS: To investigate genetic, histopathologic, and molecular features in six Black patients with COVID-19 presenting with AKI and de novo nephrotic-range proteinuria, we obtained biopsied kidney tissue, which was examined by in situ hybridization for viral detection and by NanoString for COVID-19 and acute tubular injury-associated genes. We also collected peripheral blood for APOL1 genotyping. RESULTS: This case series included six Black patients with COVID-19 (four men, two women), mean age 55 years. At biopsy day, mean serum creatinine was 6.5 mg/dl and mean urine protein-creatinine ratio was 11.5 g. Kidney biopsy specimens showed collapsing glomerulopathy, extensive foot process effacement, and focal/diffuse acute tubular injury. Three patients had endothelial reticular aggregates. We found no evidence of viral particles or SARS-CoV-2 RNA. NanoString showed elevated chemokine gene expression and changes in expression of genes associated with acute tubular injury compared with controls. All six patients had an APOL1 high-risk genotype. Five patients needed dialysis (two of whom died); one partially recovered without dialysis. CONCLUSIONS: Collapsing glomerulopathy in Black patients with COVID-19 was associated with high-risk APOL1 variants. We found no direct viral infection in the kidneys, suggesting a possible alternative mechanism: a "two-hit" combination of genetic predisposition and cytokine-mediated host response to SARS-CoV-2 infection. Given this entity's resemblance with HIV-associated nephropathy, we propose the term COVID-19-associated nephropathy to describe it.

Renal histopathological analysis of 26 postmortem findings of patients with COVID-19 in China.

Although the respiratory and immune systems are the major targets of Coronavirus Disease 2019 (COVID-19), acute kidney injury and proteinuria have also been observed. Currently, detailed pathologic examination of kidney damage in critically ill patients with COVID-19 has been lacking. To help define this we analyzed kidney abnormalities in 26 autopsies of patients with COVID-19 by light microscopy, ultrastructural observation and immunostaining. Patients were on average 69 years (19 male and 7 female) with respiratory failure associated with multiple organ dysfunction syndrome as the cause of death. Nine of the 26 showed clinical signs of kidney injury that included increased serum creatinine and/or new-onset proteinuria. By light microscopy, diffuse proximal tubule injury with the loss of brush border, non-isometric vacuolar degeneration, and even frank necrosis was observed. Occasional hemosiderin granules and pigmented casts were identified. There were prominent erythrocyte aggregates obstructing the lumen of capillaries without platelet or fibrinoid material. Evidence of vasculitis, interstitial inflammation or hemorrhage was absent. Electron microscopic examination showed clusters of coronavirus-like particles with distinctive spikes in the tubular epithelium and podocytes. Furthermore, the receptor of SARS-CoV-2, ACE2 was found to be upregulated in patients with COVID-19, and immunostaining with SARS-CoV nucleoprotein antibody was positive in tubules. In addition to the direct virulence of SARS-CoV-2, factors contributing to acute kidney injury included systemic hypoxia, abnormal coagulation, and possible drug or hyperventilation-relevant rhabdomyolysis. Thus, our studies provide direct evidence of the invasion of SARSCoV-2 into kidney tissue. These findings will greatly add to the current understanding of SARS-CoV-2 infection.

Renal histopathological analysis of 26 postmortem fi ndings of patients with COVID-19 in China

Although the respiratory and immune systems are the major targets of Coronavirus Disease 2019 (COVID-19), acute kidney injury and proteinuria have also been observed. Currently, detailed pathologic examination of kidney damage in critically ill patients with COVID-19 has been lacking. To help de fine this we analyzed kidney abnormalities in 26 autopsies of patients with COVID-19 by light microscopy, ultrastructural observation and immunostaining. Patients were on average 69 years (19 male and 7 female) with respiratory failure associated with multiple organ dysfunction syndrome as the cause of death. Nine of the 26 showed clinical signs of kidney injury that included increased serum creatinine and/or new -onset proteinuria. By light microscopy, diffuse proximal tubule injury with the loss of brush border, non -isometric vacuolar degeneration, and even frank necrosis was observed. Occasional hemosiderin granules and pigmented casts were identi fied. There were prominent erythrocyte aggregates obstructing the lumen of capillaries without platelet or fibrinoid material. Evidence of vasculitis, interstitial in flammation or hemorrhage was absent. Electron microscopic examination showed clusters of coronavirus-like particles with distinctive spikes in the tubular epithelium and podocytes. Furthermore, the receptor of SARS-CoV-2, ACE2 was found to be upregulated in patients with COVID-19, and immunostaining with SARS-CoV nucleoprotein antibody was positive in tubules. In addition to the direct virulence of SARS-CoV-2, factors contributing to acute kidney injury included systemic hypoxia, abnormal coagulation, and possible drug or hyperventilation -relevant rhabdomyolysis. Thus, our studies provide direct evidence of the invasion of SARSCoV-2 into kidney tissue. These findings will greatly add to the current understanding of SARS-CoV-2 infection.