Semiautomatic assessment of endothelial density and morphology in organ-cultured corneas - potential predictors for transplantation suitability and clinical outcome?

BACKGROUND: The quality of the endothelial cell layer is a major criterion for the approval of organ-cultured human donor-corneas for transplantation. We wanted to compare the predictive capacities of initial endothelial density and endothelium cell morphology for the approval of donor corneas for transplantation and for the clinical outcome after transplantation. METHODS: The endothelial density and endothelium morphology in organ culture were examined by semiautomatic assessment of 1031 donor corneas. We performed a statistical analysis for correlations of donor-data and cultivation parameters regarding their predictive capacities for the final approval of donor corneas for transplantation and the clinical outcome of 202 transplanted patients. RESULTS: Corneal endothelium cell density proved to be the only parameter with a certain predictive capacity with regard to the final decision, whether donor corneas are suitable for transplantation - however, the correlation was low (area under the curve [AUC] = 0.655). Endothelial cell morphology lacked any predictive power (AUC = 0.597). The clinical outcome regarding visual acuity seemed to be largely independent from both corneal endothelial cell density and morphology. Sub-analyses on transplanted patients stratified for their diagnoses vindicated these findings. CONCLUSIONS: Higher endothelial density (above a cut-off level of 2000 cells/mm2), as well as better endothelial morphology do not seem to be critical for transplant-corneal functionality in organ culture and up to 2 years after transplantation. Comparable long-term studies on graft survival are recommended to determine, whether the present endothelial density cut-off levels might be too stringent.

Hepatic Vasculopathy and Regenerative Responses of the Liver in Fatal Cases of COVID-19.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infects the nasopharynx and lungs and causes coronavirus disease-2019 (COVID-19). It may impact the heart, brain, kidney, and liver.1 Although functional impairment of the liver has been correlated with worse clinical outcomes, little is known about the pathophysiology of hepatic injury and repair in COVID-19.2,3 Histologic evaluation has been limited to small numbers of COVID-19 cases with no control subjects2,4 and demonstrated largely heterogeneous patterns of pathology.2,3.

Cardiac SARS-CoV-2 infection is associated with pro-inflammatory transcriptomic alterations within the heart.

AIMS: Cardiac involvement in COVID-19 is associated with adverse outcome. However, it is unclear whether cell-specific consequences are associated with cardiac SARS-CoV-2 infection. Therefore, we investigated heart tissue utilizing in situ hybridization, immunohistochemistry, and RNA-sequencing in consecutive autopsy cases to quantify virus load and characterize cardiac involvement in COVID-19. METHODS AND RESULTS: In this study, 95 SARS-CoV-2-positive autopsy cases were included. A relevant SARS-CoV-2 virus load in the cardiac tissue was detected in 41/95 deceased (43%). Massive analysis of cDNA ends (MACE)-RNA-sequencing was performed to identify molecular pathomechanisms caused by the infection of the heart. A signature matrix was generated based on the single-cell dataset 'Heart Cell Atlas' and used for digital cytometry on the MACE-RNA-sequencing data. Thus, immune cell fractions were estimated and revealed no difference in immune cell numbers in cases with and without cardiac infection. This result was confirmed by quantitative immunohistological diagnosis. MACE-RNA-sequencing revealed 19 differentially expressed genes (DEGs) with a q-value <0.05 (e.g. up: IFI44L, IFT3, TRIM25; down: NPPB, MB, MYPN). The upregulated DEGs were linked to interferon pathways and originate predominantly from endothelial cells. In contrast, the downregulated DEGs originate predominately from cardiomyocytes. Immunofluorescent staining showed viral protein in cells positive for the endothelial marker ICAM1 but rarely in cardiomyocytes. The Gene Ontology (GO) term analysis revealed that downregulated GO terms were linked to cardiomyocyte structure, whereas upregulated GO terms were linked to anti-virus immune response. CONCLUSION: This study reveals that cardiac infection induced transcriptomic alterations mainly linked to immune response and destruction of cardiomyocytes. While endothelial cells are primarily targeted by the virus, we suggest cardiomyocyte destruction by paracrine effects. Increased pro-inflammatory gene expression was detected in SARS-CoV-2-infected cardiac tissue but no increased SARS-CoV-2 associated immune cell infiltration was observed.