Young COVID-19 Patients Show a Higher Degree of Microglial Activation When Compared to Controls.

The severe acute respiratory syndrome-corona virus type 2 (SARS-CoV-2) is the cause of human coronavirus disease 2019 (COVID-19). Since its identification in late 2019 SARS-CoV-2 has spread rapidly around the world creating a global pandemic. Although considered mainly a respiratory disease, COVID-19 also encompasses a variety of neuropsychiatric symptoms. How infection with SARS-CoV-2 leads to brain damage has remained largely elusive so far. In particular, it has remained unclear, whether signs of immune cell and / or innate immune and reactive astrogliosis are due to direct effects of the virus or may be an expression of a non-specific reaction of the brain to a severe life-threatening disease with a considerable proportion of patients requiring intensive care and invasive ventilation activation. Therefore, we designed a case-control-study of ten patients who died of COVID-19 and ten age-matched non-COVID-19-controls to quantitatively assess microglial and astroglial response. To minimize possible effects of severe systemic inflammation and / or invasive therapeutic measures we included only patients without any clinical or pathomorphological indication of sepsis and who had not been subjected to invasive intensive care treatment. Our results show a significantly higher degree of microglia activation in younger COVID-19 patients, while the difference was less and not significant for older COVID-19 patients. The difference in the degree of reactive gliosis increased with age but was not influenced by COVID-19. These preliminary data warrants further investigation of larger patient cohorts using additional immunohistochemical markers for different microglial phenotypes.

Presence of SARS-CoV-2 RNA in the Cornea of Viremic Patients With COVID-19.

Importance: Current recommendations are to avoid tissue for corneal transplant from donors with coronavirus disease 2019 (COVID-19) or those who were recently exposed to COVID-19 owing to the lack of knowledge about the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in corneal tissues. Evidence of SARS-CoV-2 in corneal tissue would seem to have clinical relevance for corneal transplant. Objectives: To investigate the presence of viral SARS-CoV-2 RNA in corneal discs of deceased patients with confirmed COVID-19 and assess viral genomic and subgenomic RNA load, possible infectivity, and histologic abnormalities. Design, Setting, and Participants: A case series was conducted of 11 deceased patients with COVID-19 who underwent autopsy between March 20 and May 14, 2020. Eleven corneal discs (1 corneal disc per patient) were harvested for molecular detection of viral genomic and subgenomic RNA, virus isolation, and immunohistochemistry. The SARS-CoV-2 RNA loads were compared with RNA loads in the conjunctival and throat swab samples and aqueous humor, vitreous humor, and blood samples. Main Outcomes and Measures: Evidence of SARS-CoV-2 RNA in human corneas. Results: This study comprised 11 patients (6 women [55%]; mean [SD] age, 68.5 [18.8] years). In 6 of 11 eyes (55%), SARS-CoV-2 genomic RNA was detected in the cornea; subgenomic RNA was present in 4 of these 6 eyes (67%). Infectivity or the presence of viral structural proteins could not be confirmed in any eye. However, patients whose corneal disc was positive for SARS-CoV-2 RNA also had positive results for SARS-CoV-2 RNA in 4 of 6 conjunctival swab samples, 1 of 3 aqueous humor samples, 3 of 5 vitreous humor samples, and 4 of 5 blood samples. Overall, conjunctival swab samples had positive results for SARS-CoV-2 RNA in 5 of 11 cases. Postmortem SARS-CoV-2 viremia was detected in 5 of 9 patients. Conclusions and Relevance: Viral genomic and subgenomic RNA of SARS-CoV-2 was detected in the cornea of patients with COVID-19 viremia. The risk of COVID-19 infection via corneal transplant is low even in donors with SARS-CoV-2 viremia, but further research is necessary to assess the rate of SARS-CoV-2 transmission via corneal transplant.

Association of Cardiac Infection With SARS-CoV-2 in Confirmed COVID-19 Autopsy Cases.

Importance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be documented in various tissues, but the frequency of cardiac involvement as well as possible consequences are unknown. Objective: To evaluate the presence of SARS-CoV-2 in the myocardial tissue from autopsy cases and to document a possible cardiac response to that infection. Design, Setting, and Participants: This cohort study used data from consecutive autopsy cases from Germany between April 8 and April 18, 2020. All patients had tested positive for SARS-CoV-2 in pharyngeal swab tests. Exposures: Patients who died of coronavirus disease 2019. Main Outcomes and Measures: Incidence of SARS-CoV-2 positivity in cardiac tissue as well as CD3+, CD45+, and CD68+ cells in the myocardium and gene expression of tumor necrosis growth factor α, interferon γ, chemokine ligand 5, as well as interleukin-6, -8, and -18. Results: Cardiac tissue from 39 consecutive autopsy cases were included. The median (interquartile range) age of patients was 85 (78-89) years, and 23 (59.0%) were women. SARS-CoV-2 could be documented in 24 of 39 patients (61.5%). Viral load above 1000 copies per µg RNA could be documented in 16 of 39 patients (41.0%). A cytokine response panel consisting of 6 proinflammatory genes was increased in those 16 patients compared with 15 patients without any SARS-CoV-2 in the heart. Comparison of 15 patients without cardiac infection with 16 patients with more than 1000 copies revealed no inflammatory cell infiltrates or differences in leukocyte numbers per high power field. Conclusions and Relevance: In this analysis of autopsy cases, viral presence within the myocardium could be documented. While a response to this infection could be reported in cases with higher virus load vs no virus infection, this was not associated with an influx of inflammatory cells. Future investigations should focus on evaluating the long-term consequences of this cardiac involvement.