What is the association between body fat and COVID-19?
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Loading... - Martha Adu
- 27 Sep 2022
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Studies have reported obesity as a risk factor for the development, severity and associated mortality of SARS-CoV-2 infections, irrespective of age and comorbidities. Obesity is characterized by low-grade and chronic AT inflammation. Obesity may be associated with adverse SARS-CoV-2 infection outcomes due to (i) pulmonary impairments, (ii) the state of hypercoagulation and widespread systemic inflammation, (iii) impaired immunological responses, (iv) elevated endotoxemia risk among obese individuals, or (v) by direct AT infection by SARS-CoV-2. The mechanisms underlying the association have not been well-characterized and warrant further investigation.
About the study
In the present study, researchers explored whether AT infection by SARS-CoV-2 contributes to the pathogenesis of COVID-19.
Real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to detect SARS-CoV-2 presence in AT, heart, kidney, and lung samples of the autopsy case individuals. Subsequently, ribonucleic acid (RNA) in situ hybridization (ISH) was performed on epicardial AT (EAT) and pulmonary tissues obtained from the autopsy cases. Additionally, samples from non-COVID-19 patients were obtained as controls.
Further, participants undergoing cardiothoracic or bariatric surgery were enrolled, and mature adipocytes were retrieved from their visceral AT (VAT), subcutaneous AT (SAT), pericardial AT (PAT) and epicardial AT samples. PAT-derived adipocytes differentiated from preadipocytes were infected with SARS-CoV-2 to assess their angiotensin-converting enzyme 2 (ACE2) expression.
Full-length ACE2 (exon 2 to exon 3), AC2 isoforms (exon 9a to exon 10), and total ACE2 (exon 17 to exon 18) were assessed using ACE2-expressing and ACE2-non-expressing A549 (human adenocarcinoma cell line) cells. In addition, ACE2 expression was assessed using Abs (antibodies) specific for the C- and N-terminals of SARS-CoV-2.
Furthermore, SVCs (stromal vascular cells) from human AT were SARS-CoV-2-infected and assessed by RT-qPCR analysis [for the presence of SARS-CoV-2 nucleocapsid (N) gene], plaque assays, and flow cytometry (FC) analysis. SARS-CoV-2 protein production was assessed among six SVC types, i.e., macrophages, preadipocytes, dendritic cells, endothelial cells, and T and B lymphocytes, and human MDM (monocyte-derived macrophages) were also infected to obtain more macrophages. Read More...
