Excessive pericardial adipose tissue is a rich source of proinflammatory mediators in the systemic circulation and has been associated with higher levels of inflammatory markers (IL-6, TNF-α, MCP-1, CD11c, and iNOS) and fibrotic markers (collagen levels, TGF-β, matrix metalloproteinase-3) in various cardiovascular and pulmonary diseases, such as COVID-19 (Coronavirus Disease 2019), COPD, pulmonary arterial hypertension, sleep apnea syndrome, heart failure, coronary heart disease, and lung transplant recipients. Here, NOS2 is linked to COVID-19.