Robotic Tissue Sampling for Safe Post-mortem Biopsy in Infectious Corpses (preprint)

In pathology and legal medicine, the histopathological and microbiological analysis of tissue samples from infected deceased is a valuable information for developing treatment strategies during a pandemic such as COVID-19. However, a conventional autopsy carries the risk of disease transmission and may be rejected by relatives. We propose minimally invasive biopsy with robot assistance under CT guidance to minimize the risk of disease transmission during tissue sampling and to improve accuracy. A flexible robotic system for biopsy sampling is presented, which is applied to human corpses placed inside protective body bags. An automatic planning and decision system estimates optimal insertion point. Heat maps projected onto the segmented skin visualize the distance and angle of insertions and estimate the minimum cost of a puncture while avoiding bone collisions. Further, we test multiple insertion paths concerning feasibility and collisions. A custom end effector is designed for inserting needles and extracting tissue samples under robotic guidance. Our robotic post-mortem biopsy (RPMB) system is evaluated in a study during the COVID-19 pandemic on 20 corpses and 10 tissue targets, 5 of them being infected with SARS-CoV-2. The mean planning time including robot path planning is (5.72+-1.67) s. Mean needle placement accuracy is (7.19+-4.22) mm.

Replication of SARS-CoV-2 in Adipose Tissue Determines Organ and Systemic Lipid Metabolism in Hamsters and Humans (preprint)

Obesity increases the risk for poor outcome in patients with coronavirus disease-19 (COVID-19). However, the role of adipose tissue for viral propagation and potential metabolic implications are not understood. We detected SARS-CoV-2 in adipose tissue of overweight but not lean male COVID-19 patients. SARS-CoV-2 replicates to high titres in cultured mature adipocytes, a process depending on lipid accumulation and mobilization. After intranasal inoculation, we observed high viral replication in fat depots of Golden Syrian hamsters, demonstrating dissemination from the respiratory tract and subsequent propagation in adipose tissue. Following induction of pro-inflammatory responses, expression of de novo lipogenesis enzymes was suppressed in adipose tissue. This specific down-regulation was reflected by lipidomic alterations in plasma of SARS-CoV-2 infected hamsters as well as in hospitalized COVID-19 patients. Overall, our study highlights that adipose tissue is an important site of SARS-CoV-2 replication, contributing to dysregulation of systemic lipid metabolism.Funding: This study was supported by a rapid response grant from the Federal Ministry of Health (BMG; ZMV I 1-2520COR501 to GG), by DFG grants SCHE522/4-1 (LS) and SFB1328, project- ID:335447727 (JH). As part of the National Network University Medicine (NUM) funded by the Federal Ministry of Education and Research (BMBF, Germany), this work was funded within the research consortium DEFEAT PANDEMIcs, grant number 01KX2021 (FH, PL, KP, BO).Declaration of Interests: The authors declare no competing interests.Ethics Approval Statement: The Ethics Committee of the Hamburg Chamber of Physicians reviewed and approved the studies (PV7311, 2020-10353-BO-ff, WF-051/20, WF-053/20). For the preparation of primary human white adipocytes, biopsies of subcutaneous and visceral adipose tissues were taken during bariatric surgery at the Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf. All participants signed an informed consent and the study was approved by the Ethics Committee of the Hamburg Chamber of Physicians (PV4889).

Dying From Or With SARS-CoV-2 – Prospective Postmortem Evaluation of 735 Consecutive Death Cases – (preprint)

BackgroundCoronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic with significant mortality. Accurate information on the specific circumstances of death and whether patients died from or with SARS-CoV-2 is scarce.MethodsTo distinguish COVID-19 from non-COVID-19 deaths, we performed a systematic review of 735 SARS-CoV-2-associated deaths in Hamburg, Germany, from March to December 2020, using conventional autopsy, ultrasound-guided minimally invasive autopsy, postmortem computed tomography and medical records. Statistical analyses including multiple logistic regression were used to compare both cohorts.Findings84.1% (n=618) were classified as COVID-19 deaths, 6.4% (n=47) as non-COVID-19 deaths, 9.5% (n=70) remained unclear. Median age of COVID-19 deaths was 83.0 years, 54.4% were male. In the autopsy group (n=283), the majority died of pneumonia and/or diffuse alveolar damage (73.6%; n=187). Thromboses were found in 39.2% (n=62/158 cases), pulmonary embolism in 22.1% (n=56/253 cases). In 2020, annual mortality in Hamburg was about 5.5% higher than in the previous 20 years, of which 3.4% (n=618) represented COVID-19 deaths.InterpretationOur study highlights the need for mortality surveillance and postmortem examinations. The vast majority of individuals who died directly from SARS-CoV-2 infection were of advanced age and had multiple comorbidities.

Defective NET clearance contributes to sustained FXII activation in COVID-19-associated pulmonary thrombo-inflammation (preprint)

Background Coagulopathy and inflammation are hallmarks of Coronavirus disease 2019 (COVID-19) and are associated with increased mortality. Clinical and experimental data have revealed a role for neutrophil extracellular traps (NETs) in COVID-19 disease. The mechanisms that drive thrombo-inflammation in COVID-19 are poorly understood. Methods We performed proteomic analysis and immunostaining of postmortem lung tissues from COVID-19 patients and patients with other lung pathologies. We further compared coagulation factor XII (FXII) and DNase activities in plasma samples from COVID-19 patients and healthy control donors and determined NET-induced Factor XIII (FXII) activation using a chromogenic substrate assay. Findings FXII expression and activity were increased in the lung parenchyma, within the pulmonary vasculature and in fibrin-rich alveolar spaces of postmortem lung tissues from COVID-19 patients. In agreement with this, plasma FXII activation (FXIIa) was increased in samples from COVID-19 patients. Furthermore, FXIIa colocalized with NETs in COVID-19 lung tissue indicating that NETs accumulation leads to FXII contact activation in COVID-19. We further showed that an accumulation of NETs is partially due to impaired NET clearance by extracellular DNases as DNase substitution improved NET dissolution and reduced FXII activation in vitro . Interpretation Collectively, our study supports that the NETs/FXII axis contributes to the pathogenic chain of procoagulant and proinflammatory responses in COVID-19. Targeting both, NETs and FXIIa, could provide a strategy to mitigate COVID-19-induced thrombo-inflammation. Funding This study was supported by the European Union (840189), the Werner Otto Medical Foundation Hamburg (8/95) and the German Research Foundation (FR4239/1-1, A11/SFB877, B08/SFB841 and P06/KFO306).

Deep spatial profiling of COVID19 brains reveals neuroinflammation by compartmentalized local immune cell interactions and targets for intervention (preprint)

COVID-19 causes neurological symptoms that can be potentially life-threatening in up to 67 % of the patients. The underlying pathophysiological mechanisms of COVID-19 associated encephalopathy, the involved immune cells, their spatial distribution and their cellular interactions during disease remain largely unclear. In this study, we performed a 38-biomarker imaging mass cytometry analysis of the brain stem from 25 patients and additional controls to understand the local immune response during SARS-CoV-2 infection at a spatially resolved, high-dimensional single-cell level. Importantly, utilizing an unbiased image segmentation and cell classification pipeline, we observed a significant immune activation in the central nervous system (CNS) and identified novel context-specific CD8 T cell and microglial clusters. Spatially resolved single-cell analysis identified distinct phenotypes of T cells and microglial clusters, their presence in specific anatomical regions and their cellular interactions. Our analysis further highlights microglial nodules and perivascular immune cell clusters as key sites of the local immune response. It also demonstrates that disease-associated neuroinflammation is associated with severe axonal damage as a structural basis for the neurologic deficits. Finally, we identified compartment- and cluster-specific immune checkpoints that can be used for future therapeutic interventions.