On Sept. 15, 2020, UT Southwestern research suggested conditions related to obesity, including inflammation and leaky gut, leave the lungs of obese patients more susceptible to COVID-19 and may explain why they are more likely to die from the disease. The study results were published online in eLife. They suggested that drugs used to lower inflammation in the lungs could prove beneficial to obese patients with the disease.

COVID-19, caused by the novel coronavirus SARS-CoV-2, varies widely in clinical severity: Some patients are asymptomatic while others have devastating forms that have led to more than 905,000 deaths worldwide.

Several pre-existing conditions have been shown to increase the risk of COVID-19 severity, including obesity and Type 2 diabetes – two conditions that often go hand-in-hand, says Philipp Scherer, Ph.D., director of the Touchstone Center for Diabetes Research and a professor of internal medicine and cell biology at UT Southwestern.

One idea for the increased risk, they suggest, is that fat has high amounts of ACE2 receptors, entryways for the SARS-CoV-2 virus on cells. The increased numbers of these receptors in obese patients could lead to a higher viral load, a factor thought to lead to poor outcomes for COVID-19 patients.

These ACE2 receptors can be shed into circulation and end up in the lungs, specifically increasing SARS-CoV-2 concentration in lung tissue. In addition, the increased ACE2 expression in obese individuals spurs an imbalance in chemical signals that induce inflammation, fibrosis, and leaky blood vessels, all of which have the potential to cause a more severe COVID-19 infection.