Coronavirus pathogenesis in mice explains the SARS-CoV-2 multi-organ spread by red blood cell hitch-hiking (preprint)

SARS-CoV-2 infection causes a multisystemic disease that affects numerous organs beyond the respiratory system. Thus, it is well known that COVID-19 is associated with a wide range of hematological disorders; however, it remains unclear how the SARS-CoV-2 virus is able to navigate from tissue to tissue. In this work, we performed a comprehensive analysis of the pleiotropic effects of a prototypical coronavirus in its natural host, the validated preclinical model of murine hepatitis virus (MHV). Throughout this study we compared our results with the real-world data from COVID-19 patients (including autopsies). Thus, the presence of viral RNA was only detected in less than 25% of the human serum samples, whereas all had multiple positive nasal swabs for SARS-CoV-2. Notably, we found viral RNA not only in lungs, but also in heart and kidney of deceased COVID-19 patients. Subsequently, we investigated the association between viral organotropism and clinical manifestations employing the MHV murine model. Results from RT-qPCR and viral infectivity showcased the presence of viral RNA and infectious particles in multiple organs including liver, lung, brain, heart, kidney, spleen and pancreas, and even the blood of infected mice. Surprisingly, when comparing plasma and red blood cells (RBCs)-enriched fraction, higher viral load levels were detected in RBCs, with decreased RBC count, and hematocrit and hemoglobin levels in infected mice. Next, we treated infected mice with hemin triggering more aggressive symptoms. Strikingly, when combining hemin treatment with chloroquine (a compound that known to interact with the heme group and induces a conformational change in its structure) the infection and its clinical manifestations were distinctly attenuated. Computational docking suggested that heme is able to bind to MHV Spike protein in a similar way to the one, experimentally observed for SARS-CoV-2. Overall, our results lead to a global perspective of COVID-19 beyond the canonical focus on the respiratory system, and strongly support the multi-organ extent of coronavirus infection through specific interactions with RBC hemoproteins.

Pin-pointing the key hubs in the IFN-γ pathway responding to SARS-CoV-2 infection (preprint)

ABSTRACT Interferon gamma may be a potential adjuvant immunotherapy for COVID-19 patients. In this work, we assessed gene expression profiles associated with the IFN-γ pathway in response to SARS-CoV-2 infection. Employing a case-control study from SARS-CoV-2 positive and negative patients, we identified IFN-γ-associated pathways to be enriched in positive patients. Bioinformatics analyses showed upregulation of MAP2K6, CBL, RUNX3, STAT1 and JAK2 in COVID-19 positive vs. negative patients. A positive correlation was observed between STAT1 / JAK2 , which varied alongside the patient’s viral load. Expression of MX1, MX2, ISG15 and OAS1 (4 well-known IFN-stimulated genes (ISGs)) displayed upregulation in COVID-19 positive vs. negative patients. Integrative analyses showcased higher levels of ISGs which were associated with increased viral load and STAT1/JAK2 expression. Confirmation of ISGs up-regulation was performed in vitro using the A549 lung cell line treated with Poly(I:C), a synthetic analog of viral double-stranded RNA; and in different pulmonary human cell lines and ferret tracheal biopsies infected with SARS-CoV-2. A pre-clinical murine model of coronavirus infection confirmed findings displaying increased ISGs in the liver and lungs from infected mice. Altogether, these results demonstrate the role of IFN-γ and ISGs in response to SARS-CoV-2 infection, highlighting alternative druggable targets that can boost the host response.

Risk factors for developing symptomatic COVID-19 in older residents of nursing homes: A hypothesis-generating observational study (preprint)

Background. COVID-19 pandemic has had a major impact on society, including on residents of nursing homes (NH), who have a higher risk of complications and mortality due their physical and intellectual disabilities. Aim. To identify which risk factors associated with developing COVID-19 infection with symptoms in institutionalized older people. Methods. A 1-year longitudinal multicenter study was conducted in 5 NH during the period December 2019 to March 2021. The inclusion criteria used were residents aged 65 years or over, living in the NH permanently, with a diagnostic test for COVID-19 confirmed by reverse transcription polymerase chain reaction and/or serological test. The main variable was symptomatic COVID-19, with at least one of the following symptoms (fever, respiratory difficulties, cough, diarrhea, sudden urinary incontinence and disorientation or delirium). Three assessments were performed: baseline, six and twelve months follow-up. Descriptive and bivariate analysis (calculating relative risk-RR) were performed, considering a 95% confidence level and a statistically significant p <0.05. Results. Of the total sample of 78 individuals who tested positive for COVID-19, mean age 84.6 years (SD=7.8), 62 (79.5%) were female; 40 (51.3%) participants presented with COVID-19 symptoms. Living in a private NH (RR=3.6, 95% CI [1.2-11.0], p =0.023) and having suffered a stroke (RR=4.1, 95% CI [1.1-14.7], p =0.033) were positively associated with developing COVID-19 infection with symptoms. Conclusions. Having suffered a stroke and living permanently in a private health care facility were positively associated with symptomatic COVID-19 in this sample of institutionalized older people.

Association Between Periodontal Disease and the Risk of COVID-19 Complications and Mortality: A Systematic Review.

AIM: The COVID-19 pandemic has strained the world's healthcare systems. Studies have identified how the COVID-19 infections are linked to several co-morbidities such as hypertension, diabetes, cardiovascular disease, renal and pulmonary disease. It is known that periodontal disease (PD) shares the same risk factors. Moreover, both diseases are characterized by an exaggerated immune response. The aim of the study was to investigate the available evidence of a potential association between PD and the risk of COVID-19 complications and mortality. MATERIALS AND METHODS: MEDLINE/PubMed, EMBASE, Scopus, and ProQuest were searched. Studies that assess the association between PD and the risk of COVID-19 complications and mortality were eligible for inclusion. Two independent reviewers performed the selection of articles and data extraction. The New Castle Ottawa Scale was used to assess the quality of the selected studies, and the GRADE system was used to evaluate the level of confidence to support the conclusions. RESULTS: Only two studies met the eligibility criteria. One study had a low risk of bias, whereas the other had a high risk of bias. CONCLUSION: The level of confidence in the available evidence is very low. A close association between periodontitis and the risk of COVID-19 complications and mortality can neither be supported nor refuted.

Antiviral Effect of High-Dose Ivermectin in Adults with COVID-19: A Pilot Randomised, Controlled, Open Label, Multicentre Trial (preprint)

Background: There are limited antiviral options for the treatment of patients with coronavirus disease 2019 (COVID-19) that have demonstrated clinical efficacy and none of them is an oral drug. Ivermectin (IVM), a macrocytic lactone with a wide anti-parasitary spectrum, has shown potent in vitro activity against SARS-CoV-2 in cell cultures. Methods: We completed a pilot, randomized, controlled, outcome-assessor blinded clinical trial with the goal of evaluating the antiviral activity of high dose IVM in COVID-19 patients. Eligible patients were adults (aged 18 to 69 years) with mild or moderate RT-PCR confirmed SARS-CoV-2 infection within 5 days of symptoms onset. 45 patients were randomized in a 2:1 ratio to standard of care plus oral IVM at 0·6 mg/kg/day for 5 days versus standard of care. The primary endpoint was viral load reduction in respiratory secretions at day-5. Viral load in respiratory secretions was measured through quantitative RT-PCR. Concentrations of IVM in plasma were measured on multiple treatment days.Findings: The trial run between May 18 and September 29, 2020 with 45 randomized patients (30 in the IVM group and 15 controls). There was no difference in viral load reduction between groups but a significant difference in reduction was found in patients with higher median plasma IVM levels (72% IQR 59 – 77) versus untreated controls (42% IQR 31 – 73) (p=0·004). The mean ivermectin plasma concentration levels also showed a positive correlation with viral decay rate (r:0·47, p=0·02). Adverse events were reported in 5 (33%) patients in the controls and 13 (43%) in the IVM treated group, without a relationship between IVM plasma levels and adverse events.Interpretation: A concentration dependent antiviral activity of oral high dose IVM was identified in this pilot trial at a dosing regimen that was well tolerated. Large trials with clinical endpoints are necessary to determine the clinical utility of IVM in COVID-19.Trial Registration: This trial is registered with ClinicalTrials.gov, NCT004381884.Funding Statement: This work was supported by grant IP-COVID-19-625 from Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación, Argentina and Laboratorio ELEA/Phoenix, Argentina.Declaration of Interests: AK reports grants from Laboratorio Elea/Phoenix. MAT, MDG and ES are employees of Laboratorios Elea/Phoenix. SG is a moember of the Board of Directors of Laboratorio Elea/Phoenix. All other authors declare no competing interests.Ethics Approval Statement: Ethical approval was obtained from the Institutional Independent Ethics Committees and from district and national regulatory agencies. All participating individuals provided written informed consent. The trial was done in accordance with the principles of the Declaration of Helsinki.