Impact of different COVID-19 waves on kidney replacement therapy epidemiology and mortality: REMER 2020

Increased expression of SCARF genes favoring SARS-CoV-2 infection in key target organs in CKD

Background

Chronic kidney disease (CKD), especially diabetic CKD, is the condition that most increases the risk of lethal coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the underlying molecular mechanisms are unclear. SARS-CoV-2 and coronavirus-associated receptors and factors (SCARFs) regulate coronavirus cell entry and/or replication. We hypothesized that CKD may alter the expression of SCARF genes.

Methods

A literature search identified 34 SCARF genes of which we selected 21 involved in interactions between SARS-CoV/SARS-CoV-2 and host cells, and assessed their mRNA expression in target tissues of COVID-19 (kidneys, lungs, aorta and heart) in mice with adenine-induced CKD.

Results

Twenty genes were differentially expressed in at least one organ in mice with CKD. For 15 genes, the differential expression would be expected to favor SARS-CoV-2 infection and/or severity. Of these 15 genes, 13 were differentially expressed in the kidney and 8 were validated in human CKD kidney transcriptomics datasets, including those for the most common cause of CKD, diabetic nephropathy. Two genes reported to protect from SARS-CoV-2 were downregulated in at least two non-kidney target organs: Ifitm3 encoding interferon-induced transmembrane protein 3 (IFITM3) in lung and Ly6e encoding lymphocyte antigen 6 family member 6 (LY6E) in aorta.

Conclusion

CKD, including diabetic CKD, is associated with the differential expression of multiple SCARF genes in target organs of COVID-19, some of which may sensitize to SARS-CoV-2 infection. This information may facilitate developing therapeutic strategies aimed at decreasing COVID-19 severity in patients with CKD.

SCARF Genes in COVID-19 and Kidney Disease: A Path to Comorbidity-Specific Therapies

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has killed ~7 million persons worldwide. Chronic kidney disease (CKD) is the most common risk factor for severe COVID-19 and one that most increases the risk of COVID-19-related death. Moreover, CKD increases the risk of acute kidney injury (AKI), and COVID-19 patients with AKI are at an increased risk of death. However, the molecular basis underlying this risk has not been well characterized. CKD patients are at increased risk of death from multiple infections, to which immune deficiency in non-specific host defenses may contribute. However, COVID-19-associated AKI has specific molecular features and CKD modulates the local (kidney) and systemic (lung, aorta) expression of host genes encoding coronavirus-associated receptors and factors (SCARFs), which SARS-CoV-2 hijacks to enter cells and replicate. We review the interaction between kidney disease and COVID-19, including the over 200 host genes that may influence the severity of COVID-19, and provide evidence suggesting that kidney disease may modulate the expression of SCARF genes and other key host genes involved in an effective adaptive defense against coronaviruses. Given the poor response of certain CKD populations (e.g., kidney transplant recipients) to SARS-CoV-2 vaccines and their suboptimal outcomes when infected, we propose a research agenda focusing on CKD to develop the concept of comorbidity-specific targeted therapeutic approaches to SARS-CoV-2 infection or to future coronavirus infections.

Lessons from SENCOVAC: A prospective study evaluating the response to SARS-CoV-2 vaccination in the CKD spectrum

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has negatively impacted on patients of the whole CKD spectrum, causing high rates of morbi-mortality. SARS-CoV-2 vaccines opened a new era, but patients with CKD (including kidney transplant, hemodialysis and peritoneal dialysis) were systematically excluded from pivotal clinical trials. The Spanish Society of Nephrology promoted the multicentric national SENCOVAC study aimed at assessing immunological responses after vaccination in patients with CKD. During the first year after vaccination, patients with non-dialysis CKD and those on hemodialysis and peritoneal dialysis presented good anti-Spike antibody responses to vaccination, especially after receiving the third and fourth doses. However, kidney transplant recipients presented suboptimal responses after any vaccination schedule (initial, third and fourth dose). Especially worrisome is the situation of a patients with a persistently negative humoral response that do not seroconvert after boosters. In this regard, monoclonal antibodies targeting SARS-CoV-2 have been approved for high-risk patients, although they may become obsolete as the viral genome evolves. The present report reviews the current status of SARS-CoV-2 vaccination in the CKD spectrum with emphasis on lessons learned from the SENCOVAC study. Predictors of humoral response, including vaccination schedules and types of vaccines, as well as the integration of vaccines, monoclonal antibodies and antiviral agents are discussed.

Results of the first nationwide cohort study of outcomes in dialysis and kidney transplant patients before and after vaccination for COVID-19

BACKGROUND

Patients on kidney replacement therapy (KRT) have been identified as a vulnerable group during the coronavirus disease 2019 (COVID-19) pandemic. This study reports the outcomes of COVID-19 in KRT patients in Sweden, a country where patients on KRT were prioritized early in the vaccination campaign.

METHODS

Patients on KRT between January 2019 and December 2021 in the Swedish Renal Registry were included. Data were linked to national healthcare registries. The primary outcome was monthly all-cause mortality over 3 years of follow-up. The secondary outcomes were monthly COVID-19-related deaths and hospitalizations. The results were compared with the general population using standardized mortality ratios. The difference in risk for COVID-19-related outcomes between dialysis and kidney transplant recipients (KTRs) was assessed in multivariable logistic regression models before and after vaccinations started.

RESULTS

On 1 January 2020, there were 4097 patients on dialysis (median age 70 years) and 5905 KTRs (median age 58 years). Between March 2020 and February 2021, mean all-cause mortality rates increased by 10% (from 720 to 804 deaths) and 22% (from 158 to 206 deaths) in dialysis and KTRs, respectively, compared with the same period in 2019. After vaccinations started, all-cause mortality rates during the third wave (April 2021) returned to pre-COVID-19 mortality rates among dialysis patients, while mortality rates remained increased among transplant recipients. Dialysis patients had a higher risk for COVID-19 hospitalizations and death before vaccinations started {adjusted odds ratio [aOR] 2.1 [95% confidence interval (CI) 1.7-2.5]} but a lower risk after vaccination [aOR 0.5 (95% CI 0.4-0.7)] compared with KTRs.

CONCLUSIONS

The COVID-19 pandemic in Sweden resulted in increased mortality and hospitalization rates among KRT patients. After vaccinations started, a distinct reduction in hospitalization and mortality rates was observed among dialysis patients, but not in KTRs. Early and prioritized vaccinations of KRT patients in Sweden probably saved many lives.

From Cell to Symptoms: The Role of SARS-CoV-2 Cytopathic Effects in the Pathogenesis of COVID-19 and Long COVID

Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection triggers various events from molecular to tissue level, which in turn is given by the intrinsic characteristics of each patient. Given the molecular diversity characteristic of each cellular phenotype, the possible cytopathic, tissue and clinical effects are difficult to predict, which determines the heterogeneity of COVID-19 symptoms. The purpose of this article is to provide a comprehensive review of the cytopathic effects of SARS-CoV-2 on various cell types, focusing on the development of COVID-19, which in turn may lead, in some patients, to a persistence of symptoms after recovery from the disease, a condition known as long COVID. We describe the molecular mechanisms underlying virus-host interactions, including alterations in protein expression, intracellular signaling pathways, and immune responses. In particular, the article highlights the potential impact of these cytopathies on cellular function and clinical outcomes, such as immune dysregulation, neuropsychiatric disorders, and organ damage. The article concludes by discussing future directions for research and implications for the management and treatment of COVID-19 and long COVID.

Lessons from SENCOVAC: A prospective study evaluating the response to SARS-CoV-2 vaccination in the CKD spectrum

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has negatively impacted on patients of the whole CKD spectrum, causing high rates of morbi-mortality. SARS-CoV-2 vaccines opened a new era, but patients with CKD (including kidney transplant, hemodialysis and peritoneal dialysis) were systematically excluded from pivotal clinical trials. The Spanish Society of Nephrology promoted the multicentric national SENCOVAC study aimed at assessing immunological responses after vaccination in patients with CKD. During the first year after vaccination, patients with non-dialysis CKD and those on hemodialysis and peritoneal dialysis presented good anti-Spike antibody responses to vaccination, especially after receiving the third and fourth doses. However, kidney transplant recipients presented suboptimal responses after any vaccination schedule (initial, third and fourth dose). Especially worrisome is the situation of a patients with a persistently negative humoral response that do not seroconvert after boosters. In this regard, monoclonal antibodies targeting SARS-CoV-2 have been approved for high-risk patients, although they may become obsolete as the viral genome evolves. The present report reviews the current status of SARS-CoV-2 vaccination in the CKD spectrum with emphasis on lessons learned from the SENCOVAC study. Predictors of humoral response, including vaccination schedules and types of vaccines, as well as the integration of vaccines, monoclonal antibodies and antiviral agents are discussed.