Cytokeratin 18 cell death assays as biomarkers for quantification of apoptosis and necrosis in COVID-19: a prospective, observational study

Long-Term Interplay Between SARS-CoV-2 and Renal Impairment

Introduction The SARS-CoV-2 virus causes the highly contagious coronavirus disease 2019 (COVID-19), which most commonly manifests as severe acute respiratory syndrome. The virus is part of the Coronaroviridae family, a group of viruses that can cause various diseases, such as the common cold, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). The World Health Organization (WHO) declared the outbreak of COVID-19 as a pandemic on March 11, 2020. On February 26, 2020, Romania confirmed the first case of COVID-19, initiating a series of challenges that negatively impacted the lives of thousands of people. The COVID-19 pandemic has had a disproportionate effect on patients at risk of kidney damage. Patients with chronic kidney disease (CKD) are at high risk of SARS-CoV-2 infection and mortality associated with COVID-19. CKD is associated with pronounced immunodeficiency and represents a risk factor for contracting the infection, but also increases the risk of hospitalization, oxygen therapy, and prolonged treatments. The evidence regarding the management of patients with CKD undergoing renal replacement therapy (RRT) infected with SARS-CoV-2 is still misleading. While these are high-risk patients due to the presence of multiple comorbidities, especially cardiovascular, e.g., hypertension, left ventricular hypertrophy, but also diabetes, the question remains whether RRT itself is associated with a worse prognosis in patients infected with SARS-CoV-2, although infections generally induce severe complications in patients with CKD and RRT. Methods This retrospective study aims to analyze the evolution of COVID-19 disease in patients with CKD, focusing on the association with some common comorbidities such as ischemic coronary disease (ICD), obesity, and diabetes. The study included 72 hemodialyzed patients; they were hospitalized between November 2020 and February 2021 at "Sf. Ioan" Clinical Emergency Hospital, Nephrology and Dialysis Clinic; peritoneal dialysis patients were excluded. Results Older age was found to be an important risk factor for death in hemodialyzed patients admitted with COVID-19 infection. Obese patients were found to be at greater risk of mortality. Discussion This study showed that there is a complex relationship between COVID-19 infection and increased mortality in patients with CKD associating ischemic coronary disease, obesity, and diabetes.

Effectiveness of Light-Emitting Diode Epilation on Different Skin Types: A Pilot Study

Objective: This study analyzed the histological and immunohistochemical changes in hair follicles submitted to epilation with light-emitting diode (LED). Background: The use of specific wavelengths of LED leads to the absorption of photons by chromophore tissues, enabling different photophysical and photochemical events, bringing therapeutic benefits such as removing body hair. Methods: The sample included five participants, with phototypes II-V, divided into two groups. The volunteers received a session of epilation with the Holonyak^® device on the pubic region and right groin, whereas the contralateral side was kept as a control. An energy of 10 J and a cooling temperature of -5°C were used, after which the pain provoked by the equipment was questioned using the analogue pain scale. After 45 days, the punching procedure was performed in the region where skin samples were taken for histological and immunohistochemical analysis. Results: For all phototypes, in the treated area, the follicles and sebaceous glands were in a stage of involution, showing perifollicular inflammatory infiltrate with changes suggestive of apoptosis. The apoptosis process was confirmed by the increase in markers cytokeratin-18 and cleaved caspase 3, in addition to the reduced expression of Blc-2, and the lower cell proliferation (Ki67), reinforcing the action of LED based on the definite involution and resorption of the follicle, through macrophages (CD68) triggered by the inflammatory process. Conclusions: The preliminary results of this study found relevant histological changes and immunohistochemical markers in the epilation process, which may indicate the efficacy of LED in permanent hair removal.

Lung epithelial cell-derived C3 protects against pneumonia-induced lung injury

The complement component C3 is a fundamental plasma protein for host defense, produced largely by the liver. However, recent work has demonstrated the critical importance of tissue-specific C3 expression in cell survival. Here, we analyzed the effects of local versus peripheral sources of C3 expression in a model of acute bacterial pneumonia induced by Pseudomonas aeruginosa. Whereas mice with global C3 deficiency had severe pneumonia-induced lung injury, those deficient only in liver-derived C3 remained protected, comparable to wild-type mice. Human lung transcriptome analysis showed that secretory epithelial cells, such as club cells, express high levels of C3 mRNA. Mice with tamoxifen-induced C3 gene ablation from club cells in the lung had worse pulmonary injury compared with similarly treated controls, despite maintaining normal circulating C3 levels. Last, in both the mouse pneumonia model and cultured primary human airway epithelial cells, we showed that stress-induced death associated with C3 deficiency parallels that seen in Factor B deficiency rather than C3a receptor deficiency. Moreover, C3-mediated reduction in epithelial cell death requires alternative pathway component Factor B. Thus, our findings suggest that a pathway reliant on locally derived C3 and Factor B protects the lung mucosal barrier.

Early alveolar epithelial cell necrosis is a potential driver of COVID-19-induced acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) with COVID-19 is aggravated by hyperinflammatory responses even after the peak of the viral load has passed; however, its underlying mechanisms remain unclear. In the present study, analysis of the alveolar tissue injury markers and epithelial cell death markers in patients with COVID-19 revealed that COVID-19-induced ARDS was characterized by alveolar epithelial necrosis at an early disease stage. Serum levels of HMGB-1, one of the DAMPs released from necrotic cells, were also significantly elevated in these patients. Further analysis using a mouse model mimicking COVID-19-induced ARDS showed that the alveolar epithelial cell necrosis involved two forms of programmed necrosis, namely necroptosis, and pyroptosis. Finally, the neutralization of HMGB-1 attenuated alveolar tissue injury in the mouse model. Collectively, necrosis, including necroptosis and pyroptosis, is the predominant form of alveolar epithelial cell death at an early disease stage and subsequent release of DAMPs is a potential driver of COVID-19-induced ARDS.

Autoimmune Effect of Antibodies against the SARS-CoV-2 Nucleoprotein

COVID-19 caused by SARS-CoV-2 is continuing to spread around the world and drastically affect our daily life. New strains appear, and the severity of the course of the disease itself seems to be decreasing, but even people who have been ill on an outpatient basis suffer post-COVID consequences. Partly, it is associated with the autoimmune reactions, so debates about the development of new vaccines and the need for vaccination/revaccination continue. In this study we performed an analysis of the antibody response of patients with COVID-19 to linear and conformational epitopes of viral proteins using ELISA, chip array and western blot with analysis of correlations between antibody titer, disease severity, and complications. We have shown that the presence of IgG antibodies to the nucleoprotein can deteriorate the course of the disease, induce multiple direct COVID-19 symptoms, and contribute to long-term post-covid symptoms. We analyzed the cross reactivity of antibodies to SARS-CoV-2 with own human proteins and showed that antibodies to the nucleocapsid protein can bind to human proteins. In accordance with the possibility of HLA presentation, the main possible targets of the autoantibodies were identified. People with HLA alleles A01:01; A26:01; B39:01; B15:01 are most susceptible to the development of autoimmune processes after COVID-19.

The Role of Epithelial Damage in the Pulmonary Immune Response

Pulmonary epithelial cells are widely considered to be the first line of defence in the lung and are responsible for coordinating the innate immune response to injury and subsequent repair. Consequently, epithelial cells communicate with multiple cell types including immune cells and fibroblasts to promote acute inflammation and normal wound healing in response to damage. However, aberrant epithelial cell death and damage are hallmarks of pulmonary disease, with necrotic cell death and cellular senescence contributing to disease pathogenesis in numerous respiratory diseases such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and coronavirus disease (COVID)-19. In this review, we summarise the literature that demonstrates that epithelial damage plays a pivotal role in the dysregulation of the immune response leading to tissue destruction and abnormal remodelling in several chronic diseases. Specifically, we highlight the role of epithelial-derived damage-associated molecular patterns (DAMPs) and senescence in shaping the immune response and assess their contribution to inflammatory and fibrotic signalling pathways in the lung.

Blood concentrations of proapoptotic sFas and antiapoptotic Bcl2 and COVID-19 patient mortality

Background: There are no data on circulating concentrations of sFas (proapoptotic protein of extrinsic pathway) and Bcl2 (antiapoptotic protein of intrinsic pathway) in COVID-19 patients. Thus, our objective study was to determine whether an association exists between serum concentrations of sFas and Bcl2 and COVID-19 patient mortality.Methods: This observational and prospective study of COVID-19 patients was performed in eight Intensive Care Units (ICU) from Canary Islands (Spain). Serum levels of sFas and Bcl2 at ICU admission were determined. Mortality at 30 days was the end-point study.Results: Surviving patients (n = 42) compared to non-surviving (n = 11) had lower APACHE-II (p < 0.001), lower SOFA (p = 0.004), lower serum sFas levels (p = 0.001) and higher serum Bcl2 levels (p < 0.001). Logistic regression showed an association between high serum sFas levels and mortality after controlling for APACHE-II (OR = 1.004; 95% CI = 1.101-1.007; p = 0.01) or SOFA (OR = 1.003; 95% CI = 1.101-1.106; p = 0.004), and between low serum Bcl2 levels and mortality after controlling for APACHE-II (OR = 0.927; 95% CI = 0.873-0.984; p = 0.01) or SOFA (OR = 0.949; 95% CI = 0.913-0.987; p = 0.01).Conclusions: Thus, to the best of our knowledge, this is the first study reporting blood levels of sFas and Bcl2 in COVID-19 patients and its association with mortality.