ABSTRACT
Background: In COVID-19 survivors, there is an increased prevalence of pulmonary fibrosis of which the underlying molecular mechanisms are poorly understood. Aims and objectives: In this study, we aimed to gain insights into the evolution of pulmonary fibrogenesis in COVID19. Method(s): In this multicentric study, n=12 patients who succumbed to COVID-19 due to progressive respiratory failure were assigned to an early and late group (death within <=7 and >7 days of hospitalization, respectively) and compared to n=11 healthy controls;mRNA and protein expression were analyzed using a fibrosis-specific panel and immunostaining. Biological pathway analysis was performed using two different gene expression databases. Result(s): Median duration of hospitalization until death was 3 (IQR25-75, 3-3.75) and 14 (12.5-14) days in the early and late group, respectively. Fifty-eight out of 770 analyzed genes showed a significantly altered expression signature in COVID-19 compared to controls in a time-dependent manner. The entire study group showed an increased expression of Bone Marrow Stromal Cell Antigen 2 (BST2) and interleukin-1 receptor 1 (IL1R1), independent of hospitalization time. In the early group, there was increased activity of inflammation-related genes and pathways, while fibrosis-related genes (particularly PDGFRB) and pathways dominated in the late group. Conclusion(s): After the first week of hospitalization, there is a shift from pro-inflammatory to fibrogenic activity in severe COVID-19. IL1R1 and PDGFRB may serve as potential therapeutic targets in future studies.
ABSTRACT
Background and aims: Vaccination is one of the most important countermeasures in the ongoing COVID19-pandemic. Pharmacovigilance concerns, however, emerged after very rare, but potentially disastrous thrombotic complications following vaccination with ChAdOx1. The underlying pathology was described as platelet factor 4 antibody mediated vaccine-induced immune thrombotic thrombocytopenia (VITT). Mechanisms of immunothrombosis including the regulation of neutrophil extracellular traps (NETs) might be of crucial importance in VITT. Methods: In this study, we had the exceptional opportunity to investigate blood and thrombus samples of a patient who suffered severe ischaemic stroke due to VITT undergoing successful mechanical thrombectomy (MT) in comparison to 13 control stroke patients with similar clinical characteristics without VITT. Cerebral thrombi were stained for complement factors, NETs-markers, DNase and LL-37 and were histologically assessed. In blood samples before MT and 7 days later, cell-free DNA, myeloperoxidase-histone complexes, myeloperoxidase activity, DNase activity, LL-37 and inflammatory cytokines were determined. Results: We identified NETs-markers in thrombi of all patients. The thrombus of the VITT-patient, however, exclusively revealed complement factors and high amounts of NETs-degrading DNase and LL-37, which protects NETs from degradation. In accordance, ex vivo and in vitro studies also implied a disturbed regulation of NETs in VITT-samples. Moreover, we found markedly pronounced temporal changes of specific circulating cytokines in the VITT-case. Conclusions: The results of this study suggest a disturbed endogenous regulation of NETs in VITT involving a pro-inflammatory response and fulminant clinical course. Further studies are warranted to confirm our results and to provide deeper insights into the causative mechanisms.
ABSTRACT
Imaging intact human organs from the organ to the cellular scale in three dimensions is a goal of biomedical imaging. To meet this challenge, we developed hierarchical phase-contrast tomography (HiP-CT), an X-ray phase propagation technique using the European Synchrotron Radiation Facility (ESRF)'s Extremely Brilliant Source (EBS). The spatial coherence of the ESRF-EBS combined with our beamline equipment, sample preparation and scanning developments enabled us to perform non-destructive, three-dimensional (3D) scans with hierarchically increasing resolution at any location in whole human organs. We applied HiP-CT to image five intact human organ types: brain, lung, heart, kidney and spleen. HiP-CT provided a structural overview of each whole organ followed by multiple higher-resolution volumes of interest, capturing organotypic functional units and certain individual specialized cells within intact human organs. We demonstrate the potential applications of HiP-CT through quantification and morphometry of glomeruli in an intact human kidney and identification of regional changes in the tissue architecture in a lung from a deceased donor with coronavirus disease 2019 (COVID-19).