Comparing the Cytokine Storms of COVID-19 and Pandemic Influenza

COVID-19 patients with high TNF/IFN-γ levels show hallmarks of PANoptosis, an inflammatory cell death

TNF and IFN-γ trigger cell damage during SARS CoV-2 infection; these cytokines can induce senescence and a cell death process called PANoptosis. This study included 138 vaccine-naïve COVID-19 patients, who were divided into four groups (Gp) according to the plasma level of TNF and IFN-γ (High [Hi] or Normal-Low [No-Low]), Gp 1: TNFHi/IFNγHi; Gp 2: TNFHi/IFNγNo-Low; Gp 3: TNFNo-Low/IFNγHi; and Gp 4: TNFNo-Low/IFNγNo-Low. Thirty-five apoptosis-related proteins and molecules related to cell death and senescence were evaluated. Our results showed that groups did not display differences in age and comorbidities. However, 81% of the Gp 1 patients had severe COVID-19, and 44% died. Notably, the p21/CDKN1A was increased in Gp 2 and Gp 3. Moreover, Gp 1 showed higher TNFR1, MLKL, RIPK1, NLRP3, Caspase 1, and HMGB-1 levels, suggesting elevated TNF and IFN-γ levels simultaneously activate diverse cell death pathways because it is not observed when only one of these cytokines is increased. Thus, high TNF/IFN-γ levels are predominant in severe COVID-19 status, and patients display cell alterations associated with the activation of diverse cell death pathways, including a possible senescent phenotype.

In vitro evidence against productive SARS-CoV-2 infection of human testicular cells: Bystander effects of infection mediate testicular injury

The hallmark of severe COVID-19 involves systemic cytokine storm and multi-organ injury including testicular inflammation, reduced testosterone, and germ cell depletion. The ACE2 receptor is also expressed in the resident testicular cells, however, SARS-CoV-2 infection and mechanisms of testicular injury are not fully understood. The testicular injury could be initiated by direct virus infection or exposure to systemic inflammatory mediators or viral antigens. We characterized SARS-CoV-2 infection in different human testicular 2D and 3D culture systems including primary Sertoli cells, Leydig cells, mixed seminiferous tubule cells (STC), and 3D human testicular organoids (HTO). Data shows that SARS-CoV-2 does not productively infect any testicular cell type. However, exposure of STC and HTO to inflammatory supernatant from infected airway epithelial cells and COVID-19 plasma decreased cell viability and resulted in the death of undifferentiated spermatogonia. Further, exposure to only SARS-CoV-2 Envelope protein caused inflammatory response and cytopathic effects dependent on TLR2, while Spike 1 or Nucleocapsid proteins did not. A similar trend was observed in the K18-hACE2 transgenic mice which demonstrated a disrupted tissue architecture with no evidence of virus replication in the testis that correlated with peak lung inflammation. Virus antigens including Spike 1 and Envelope proteins were also detected in the serum during the acute stage of the disease. Collectively, these data strongly suggest that testicular injury associated with SARS-CoV-2 infection is likely an indirect effect of exposure to systemic inflammation and/or SARS-CoV-2 antigens. Data also provide novel insights into the mechanism of testicular injury and could explain the clinical manifestation of testicular symptoms associated with severe COVID-19.

Polymeric Materials as Indispensable Tools to Fight RNA Viruses: SARS-CoV-2 and Influenza A

Towards the end of 2019 in Wuhan, suspicions of a new dangerous virus circulating in the air began to arise. It was the start of the world pandemic coronavirus disease 2019 (COVID-19). Since then, considerable research data and review papers about this virus have been published. Hundreds of researchers have shared their work in order to achieve a better comprehension of this disease, all with the common goal of overcoming this pandemic. The coronavirus is structurally similar to influenza A. Both are RNA viruses and normally associated with comparable infection symptoms. In this review, different case studies targeting polymeric materials were appraised to highlight them as an indispensable tool to fight these RNA viruses. In particular, the main focus was how polymeric materials, and their versatile features could be applied in different stages of viral disease, i.e., in protection, detection and treatment.

FDA-Approved Inhibitors of RTK/Raf Signaling Potently Impair Multiple Steps of In Vitro and Ex Vivo Influenza A Virus Infections

Influenza virus (IV) infections pose a burden on global public health with significant morbidity and mortality. The limited range of currently licensed IV antiviral drugs is susceptible to the rapid rise of resistant viruses. In contrast, FDA-approved kinase inhibitors can be repurposed as fast-tracked host-targeted antivirals with a higher barrier of resistance. Extending our recent studies, we screened 21 FDA-approved small-molecule kinase inhibitors (SMKIs) and identified seven candidates as potent inhibitors of pandemic and seasonal IV infections. These SMKIs were further validated in a biologically and clinically relevant ex vivo model of human precision-cut lung slices. We identified steps of the virus infection cycle affected by these inhibitors (entry, replication, egress) and found that most SMKIs affected both entry and egress. Based on defined and overlapping targets of these inhibitors, the candidate SMKIs target receptor tyrosine kinase (RTK)-mediated activation of Raf/MEK/ERK pathways to limit influenza A virus infection. Our data and the established safety profiles of these SMKIs support further clinical investigations and repurposing of these SMKIs as host-targeted influenza therapeutics.

Tocilizumab vs. baricitinib in hospitalized severe COVID-19 patients: results from a real-world cohort

Background

Tocilizumab and baricitinib are recommended treatment options for hospitalized COVID-19 patients requiring oxygen support. Literature about its efficacy and safety in a head-to-head comparison is scarce.

Methods

Hospitalized COVID-19 patients requiring oxygen were treated with tocilizumab or baricitinib additionally to dexamethasone. Tocilizumab was available from February till the 19th of September 2021 and baricitinib from 21st of September. The primary outcome was in-hospital mortality. Secondary outcome parameters were progression to mechanical ventilation (MV), length-of-stay (LOS) and potential side effects.

Results

159 patients (tocilizumab 68, baricitinib 91) with a mean age of 60.5 years, 64% male were included in the study. Tocilizumab patients were admitted 1 day earlier, were in a higher WHO category at the time of inclusion and had a higher CRP level on admission and treatment initiation. Patients receiving Tocilizumab were treated with remdesivir more often and only patients in the baricitinib group were treated with monoclonal antibodies. Other characteristics did not differ significantly. In-hospital mortality (18% vs. 11%, p = 0.229), progression to MV (19% vs. 11%, p = 0.173) and LOS (13 vs. 12 days, p = 0.114) did not differ between groups. Side effects were equally distributed between groups, except ALAT elevation which was significantly more often observed in the tocilizumab group (43% vs. 25%, p = 0.021).

Conclusions

In-hospital mortality, progression to MV and LOS were not significantly different in patients treated with tocilizumab or baricitinib additionally to standard of care. Both drugs seem equally effective but further head-to-head trials are needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-022-01915-7.