Postmortem Kidney Pathology Findings in Patients with COVID-19

Hunting coronavirus by transmission electron microscopy - a guide to SARS-CoV-2-associated ultrastructural pathology in COVID-19 tissues

Transmission electron microscopy has become a valuable tool to investigate tissues of COVID‐19 patients because it allows visualisation of SARS‐CoV‐2, but the ‘virus‐like particles’ described in several organs have been highly contested. Because most electron microscopists in pathology are not accustomed to analysing viral particles and subcellular structures, our review aims to discuss the ultrastructural changes associated with SARS‐CoV‐2 infection and COVID‐19 with respect to pathology, virology and electron microscopy. Using micrographs from infected cell cultures and autopsy tissues, we show how coronavirus replication affects ultrastructure and put the morphological findings in the context of viral replication, which induces extensive remodelling of the intracellular membrane systems. Virions assemble by budding into the endoplasmic reticulum–Golgi intermediate complex and are characterised by electron‐dense dots of cross‐sections of the nucleocapsid inside the viral particles. Physiological mimickers such as multivesicular bodies or coated vesicles serve as perfect decoys. Compared to other in‐situ techniques, transmission electron microscopy is the only method to visualise assembled virions in tissues, and will be required to prove SARS‐CoV‐2 replication outside the respiratory tract. In practice, documenting in tissues the characteristic features seen in infected cell cultures seems to be much more difficult than anticipated. In our view, the hunt for coronavirus by transmission electron microscopy is still on.

COVID-19-associated acute kidney injury: consensus report of the 25th Acute Disease Quality Initiative (ADQI) Workgroup

Kidney involvement in patients with coronavirus disease 2019 (COVID-19) is common, and can range from the presence of proteinuria and haematuria to acute kidney injury (AKI) requiring renal replacement therapy (RRT; also known as kidney replacement therapy). COVID-19-associated AKI (COVID-19 AKI) is associated with high mortality and serves as an independent risk factor for all-cause in-hospital death in patients with COVID-19. The pathophysiology and mechanisms of AKI in patients with COVID-19 have not been fully elucidated and seem to be multifactorial, in keeping with the pathophysiology of AKI in other patients who are critically ill. Little is known about the prevention and management of COVID-19 AKI. The emergence of regional 'surges' in COVID-19 cases can limit hospital resources, including dialysis availability and supplies; thus, careful daily assessment of available resources is needed. In this Consensus Statement, the Acute Disease Quality Initiative provides recommendations for the diagnosis, prevention and management of COVID-19 AKI based on current literature. We also make recommendations for areas of future research, which are aimed at improving understanding of the underlying processes and improving outcomes for patients with COVID-19 AKI.

COVID-19-associated acute kidney injury: consensus report of the 25th Acute Disease Quality Initiative (ADQI) Workgroup

Kidney involvement in patients with coronavirus disease 2019 (COVID-19) is common, and can range from the presence of proteinuria and haematuria to acute kidney injury (AKI) requiring renal replacement therapy (RRT; also known as kidney replacement therapy). COVID-19-associated AKI (COVID-19 AKI) is associated with high mortality and serves as an independent risk factor for all-cause in-hospital death in patients with COVID-19. The pathophysiology and mechanisms of AKI in patients with COVID-19 have not been fully elucidated and seem to be multifactorial, in keeping with the pathophysiology of AKI in other patients who are critically ill. Little is known about the prevention and management of COVID-19 AKI. The emergence of regional 'surges' in COVID-19 cases can limit hospital resources, including dialysis availability and supplies; thus, careful daily assessment of available resources is needed. In this Consensus Statement, the Acute Disease Quality Initiative provides recommendations for the diagnosis, prevention and management of COVID-19 AKI based on current literature. We also make recommendations for areas of future research, which are aimed at improving understanding of the underlying processes and improving outcomes for patients with COVID-19 AKI.

The Social Brain and Emotional Contagion: COVID-19 Effects

BACKGROUND AND OBJECTIVES

Coronavirus disease 2019 (COVID-19) is a highly contagious infectious disease, responsible for a global pandemic that began in January 2020. Human/COVID-19 interactions cause different outcomes ranging from minor health consequences to death. Since social interaction is the default mode by which individuals communicate with their surroundings, different modes of contagion can play a role in determining the long-term consequences for mental health and emotional well-being. We examined some basic aspects of human social interaction, emphasizing some particular features of the emotional contagion. Moreover, we analyzed the main report that described brain damage related to the COVID-19 infection. Indeed, the goal of this review is to suggest a possible explanation for the relationships among emotionally impaired people, brain damage, and COVID-19 infection.

RESULTS

COVID-19 can cause several significant neurological disorders and the pandemic has been linked to a rise in people reporting mental health problems, such as depression and anxiety. Neurocognitive symptoms associated with COVID-19 include delirium, both acute and chronic attention and memory impairment related to hippocampal and cortical damage, as well as learning deficits in both adults and children.

CONCLUSIONS

Although our knowledge on the biology and long-term clinical outcomes of the COVID-19 infection is largely limited, approaching the pandemic based on lessons learnt from previous outbreaks of infectious diseases and the biology of other coronaviruses will provide a suitable pathway for developing public mental health strategies, which could be positively translated into therapeutic approaches, attempting to improve stress coping responses, thus contributing to alleviate the burden driven by the pandemic.

Effect of COVID-19 on Kidney Disease Incidence and Management

The COVID-19 outbreak has had substantial effects on the incidence and management of kidney diseases, including AKI, ESKD, GN, and kidney transplantation. Initial reports from China suggested a lower AKI incidence in patients with COVID-19, but more recent studies from North America reveal a much higher incidence, likely due to the higher prevalence of comorbid conditions, such as hypertension, diabetes, and CKD. AKI in this setting is associated with worse outcomes, including the requirement for vasopressors or mechanical ventilation and death. Performing RRT in those with AKI poses challenges, such as limiting exposure of staff, preserving PPE, coagulopathy, and hypoxemia due to acute respiratory distress syndrome. Continuous RRT is the preferred modality, with sustained low-efficiency dialysis also an option, both managed without 1:1 hemodialysis nursing support. Regional citrate is the preferred anticoagulation, but systemic unfractionated heparin may be used in patients with coagulopathy. The ultrafiltration rate has to be set carefully, taking into consideration hypotension, hypoxemia, and responsiveness to presser and ventilatory support. The chance of transmission puts in-center chronic hemodialysis and other immunosuppressed patients at particularly increased risk. Limited data show that patients with CKD are also at increased risk for more severe disease, if infected. Little is known about the virus's effects on immunocompromised patients with glomerular diseases and kidney transplants, which introduces challenges for management of immunosuppressant regimens. Although there are no standardized guidelines regarding the management of immunosuppression, several groups recommend stopping the antimetabolite in hospitalized transplant patients and continuing a reduced dose of calcineurin inhibitors. This comprehensive review critically appraises the best available evidence regarding the effect of COVID-19 on the incidence and management of kidney diseases. Where evidence is lacking, current expert opinion and clinical guidelines are reviewed, and knowledge gaps worth investigation are identified.

Association of Proteinuria and Hematuria with Acute Kidney Injury and Mortality in Hospitalized Patients with COVID-19

INTRODUCTION

Acute kidney injury (AKI) is strongly associated with poor outcomes in hospitalized patients with coronavirus disease 2019 (COVID-19), but data on the association of proteinuria and hematuria are limited to non-US populations. In addition, admission and in-hospital measures for kidney abnormalities have not been studied separately.

METHODS

This retrospective cohort study aimed to analyze these associations in 321 patients sequentially admitted between March 7, 2020 and April 1, 2020 at Stony Brook University Medical Center, New York. We investigated the association of proteinuria, hematuria, and AKI with outcomes of inflammation, intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), and in-hospital death. We used ANOVA, t test, χ2 test, and Fisher's exact test for bivariate analyses and logistic regression for multivariable analysis.

RESULTS

Three hundred patients met the inclusion criteria for the study cohort. Multivariable analysis demonstrated that admission proteinuria was significantly associated with risk of in-hospital AKI (OR 4.71, 95% CI 1.28-17.38), while admission hematuria was associated with ICU admission (OR 4.56, 95% CI 1.12-18.64), IMV (OR 8.79, 95% CI 2.08-37.00), and death (OR 18.03, 95% CI 2.84-114.57). During hospitalization, de novo proteinuria was significantly associated with increased risk of death (OR 8.94, 95% CI 1.19-114.4, p = 0.04). In-hospital AKI increased (OR 27.14, 95% CI 4.44-240.17) while recovery from in-hospital AKI decreased the risk of death (OR 0.001, 95% CI 0.001-0.06).

CONCLUSION

Proteinuria and hematuria both at the time of admission and during hospitalization are associated with adverse clinical outcomes in hospitalized patients with COVID-19.

Persistence of viral RNA, pneumocyte syncytia and thrombosis are hallmarks of advanced COVID-19 pathology

BACKGROUND

COVID-19 is a deadly pulmonary disease with peculiar characteristics, which include variable clinical course and thrombophilia. A thorough understanding of the pathological correlates of the disease is still missing.

METHODS

Here we report the systematic analysis of 41 consecutive post-mortem samples from individuals who died of COVID-19. Histological analysis is complemented by immunohistochemistry for cellular and viral antigens and the detection of viral genomes by in situ RNA hybridization.

FINDINGS

COVID-19 is characterized by extensive alveolar damage (41/41 of patients) and thrombosis of the lung micro- and macro-vasculature (29/41, 71%). Thrombi were in different stages of organization, consistent with their local origin. Pneumocytes and endothelial cells contained viral RNA even at the later stages of the disease. An additional feature was the common presence of a large number of dysmorphic pneumocytes, often forming syncytial elements (36/41, 87%). Despite occasional detection of virus-positive cells, no overt signs of viral infection were detected in other organs, which showed non-specific alterations.

INTERPRETATION

COVID-19 is a unique disease characterized by extensive lung thrombosis, long-term persistence of viral RNA in pneumocytes and endothelial cells, along with the presence of infected cell syncytia. Several of COVID-19 features might be consequent to the persistence of virus-infected cells for the duration of the disease.

FUNDING

This work was supported by a King's Together Rapid COVID-19 Call grant from King's College London. MG is supported by the European Research Council (ERC) Advanced Grant 787971 "CuRE" and by Programme Grant RG/19/11/34633 from the British Heart Foundation.

Novel Evidence of Acute Kidney Injury in COVID-19

The coronavirus 2019 (COVID-19) pandemic has caused a huge impact on health and economic issues. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes cellular damage by entry mediated by the angiotensin-converting enzyme 2 of the host cells and its conjugation with spike proteins of SARS-CoV-2. Beyond airway infection and acute respiratory distress syndrome, acute kidney injury is common in SARS-CoV-2-associated infection, and acute kidney injury (AKI) is predictive to multiorgan dysfunction in SARS-CoV-2 infection. Beyond the cytokine storm and hemodynamic instability, SARS-CoV-2 might directly induce kidney injury and cause histopathologic characteristics, including acute tubular necrosis, podocytopathy and microangiopathy. The expression of apparatus mediating SARS-CoV-2 entry, including angiotensin-converting enzyme 2, transmembrane protease serine 2 (TMPRSS2) and a disintegrin and metalloprotease 17 (ADAM17), within the renal tubular cells is highly associated with acute kidney injury mediated by SARS-CoV-2. Both entry from the luminal and basolateral sides of the renal tubular cells are the possible routes for COVID-19, and the microthrombi associated with severe sepsis and the dysregulated renin-angiotensin-aldosterone system worsen further renal injury in SARS-CoV-2-associated AKI. In the podocytes of the glomerulus, injured podocyte expressed CD147, which mediated the entry of SARS-CoV-2 and worsen further foot process effacement, which would worsen proteinuria, and the chronic hazard induced by SARS-CoV-2-mediated kidney injury is still unknown. Therefore, the aim of the review is to summarize current evidence on SARS-CoV-2-associated AKI and the possible pathogenesis directly by SARS-CoV-2.

A call to action to evaluate renal functional reserve in patients with COVID-19

Coronavirus disease 2019 (COVID-19) poses an unprecedented challenge to world health systems, substantially increasing hospitalization and mortality rates in all affected countries. Being primarily a respiratory disease, COVID-19 is mainly associated with pneumonia or minor upper respiratory tract symptoms; however, different organs can sustain considerable (if not terminal) damage because of coronavirus. Acute kidney injury is the most common complication of COVID-19-related pneumonia, and more than 20% of patients requiring ventilatory support develop renal failure. Additionally, chronic kidney disease is a major risk factor for COVID-19 severity and mortality. All these data demonstrate the relevance of renal function assessment in patients with COVID-19 and the need of early kidney-directed diagnostic and therapeutic approaches. However, the sole assessment of renal function could be not entirely indicative of kidney tissue status. In this viewpoint, we discuss the clinical significance and potential relevance of renal functional reserve evaluation in patients with COVID-19.

More than Pneumonia: Distinctive Features of SARS-Cov-2 Infection. From Autopsy Findings to Clinical Implications: A Systematic Review

Despite safety recommendations for the management of corpses with COVID-19 infection and the high number of deaths worldwide, the post-mortem investigation rate is extremely low as well as the scientific contributions describing the pathological features. The first results of post-mortem investigations provided interesting findings and contributed to promoting unexplored therapeutic approaches and new frontiers of research. A systematic review is provided with the aim of summarizing all autopsy studies up to February 2020 in which a complete post-mortem investigation in patients with COVID-19 disease was performed, focusing on histopathological features. We included case reports, case series, retrospective and prospective studies, letters to the editor, and reviews. A total of 28 studies fulfilled the inclusion criteria, producing a pooled dataset of 407 full autopsies. Analyzing the medical history data, only 12 subjects had died without any comorbidities (for 15 cases the data were not available). The post-mortem investigation highlighted that acute respiratory distress syndrome (ARDS) and multiple organ failure represent the main clinical features of COVID-19 disease, often leading to pulmonary thromboembolism and superimposed bronchopneumonia. The discussed data showed a strict relationship among the inflammatory processes, diffuse alveolar, and endothelial damage. In light of these results, the full autopsy can be considered as the gold standard to investigate unknown infections or pathogens resulting in death.

Severe Acute Respiratory Syndrome Coronavirus 2 Induced Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome affecting adults and children. Collapsing focal segmental glomerulosclerosis (FSGS), one of five histologic variants of FSGS is described as segmental or global collapse and sclerosis of the glomerular tufts and has been frequently associated with human immunodeficiency virus-associated nephropathy (HIVAN). Its association with other viral and non-viral causes, medications and other disease states has since been established. Due to its resistance to therapy, rapid progression to end-stage renal disease (ESRD) and overall poorer prognosis, identification with electron microscopy examination of the kidney biopsy sample is required during evaluation.

COVID-19 infection and the kidney

Despite initial reports, renal involvement, including acute kidney injury, has emerged as a serious complication of COVID-19 disease, particularly in critically ill patients. The reported prevalence varies considerably, which may reflect reporting practices, although differences in pre-existing comorbidities and socioeconomic factors, and differences between ethnic groups, almost certainly contribute. Renal involvement may present as an active urinary sediment or as changes in serum creatinine levels and urine output leading to acute kidney injury. In common with acute kidney injury complicating critical illness, the cause is often multifactorial and often presents as part of a multiorgan dysfunction syndrome. Treatment is, in the main, supportive, with kidney replacement therapy required in nearly 25% of reported cases. Few data currently exist as to the long-term burden of COVID-19-associated acute kidney injury but evidence suggests that only approximately one-third of patients are discharged with recovered renal function.

Proximal tubular dysfunction in patients with COVID-19: what have we learnt so far?

Recent studies have reported a variety of urine abnormalities in patients hospitalized due to severe acute respiratory syndrome coronavirus 2 infection. In a single-center study from Belgium, Werion et al. present a concise investigation of tubular dysfunction in patients with coronavirus disease 2019, identifying potential risk factors for increased disease severity. These data complement current evidence regarding severe acute respiratory syndrome coronavirus 2 presence and potential infection in the kidney.

Pathophysiology and Pathology of Acute Kidney Injury in Patients With COVID-19

Acute kidney injury (AKI) is common among hospitalized patients with Coronavirus Infectious Disease 2019 (COVID-19), with the occurrence of AKI ranging from 0.5% to 80%. The variability in the occurrence of AKI has been attributed to the difference in geographic locations, race/ethnicity, and severity of illness. AKI among hospitalized patients is associated with increased length of stay and in-hospital deaths. Even patients with AKI who survive to hospital discharge are at risk of developing chronic kidney disease or end-stage kidney disease. An improved knowledge of the pathophysiology of AKI in COVID-19 is crucial to mitigate and manage AKI and to improve the survival of patients who developed AKI during COVID-19. The goal of this article is to provide our current understanding of the etiology and the pathophysiology of AKI in the setting of COVID-19.