The Role of Obesity in Severe COVID-19 Pathophysiology

This is a mono-center, prospective cohort study involving both a test group and a control group. The test group comprises patients with obesity eligible for bariatric surgery at Franciscus Hospital, while the control group consists of age- (maximum 5-year difference) and sex-matched non-obese healthcare workers at Franciscus Hospital. Blood samples will be collected from all participants at a single time point. Obese patients will be approached for informed consent during their intake appointments, typically weeks to months before their bariatric surgery. Blood samples will be collected before surgery or during surgery to minimize any potential adverse effects. Collaborating researchers from the surgery department will manage the inclusion of obese patients and coordinate their blood collection. For the non-obese control group, investigators from MMI will manage participant inclusion and blood sample collection. Participants from Franciscus Hospital with obesity (Cohort 1) and healthcare workers without obesity (Cohort 2) will undergo a single venipuncture after an 8-hour fasting period. A total of 40 mL of blood will be collected in four 10 mL EDTA tubes. At the Medical Microbiology and Infection Control (MMI) laboratory of Franciscus, blood samples will be collected after which these are sent to the Center for Infection and Molecular Medicine (CIMM) laboratory in Amsterdam UMC. Here, blood will be processed (i.e., isolation of plasma, monocytes, and remaining peripheral blood mononuclear cells (PBMCs)), where after monocytes will be put into culture to become monocyte-derived macrophages. Macrophage stimulations and additional macrophage analyses will be performed at Amsterdam UMC. Data obtained from analyses in Amsterdam UMC will be further analyzed in Amsterdam UMC by coordinating investigator Ashwin Mak (who is also affiliated at CIMM in Amsterdam UMC) and co-investigator Dr. Jeroen den Dunnen. Monocytes and plasma will be stored in Amsterdam UMC until the end of this study, where after the remaining materials will be transported to Franciscus. Isolated PBMCs and plasma will be transported in the following days after isolation to Franciscus MMI for T cell stimulations and antibody analyses. In the analyses overview below, the location where each analysis will be performed is noted (i.e., MMI and CIMM). Coded samples and data will be stored at Amsterdam UMC until the end of this study, where after these samples are destroyed and data are deleted. MTA and DTA documents will be prepared for the transfer of blood and data to Amsterdam UMC.