Does SARS-CoV-2 Target and Exploit Fat Tissue?

More than a year ago in Obesity, Paul Ryan and Noel Caplice laid out a theoretical framework suggesting SARS-CoV-2 (the virus that causes COVID-19) might target and exploit fat tissue. They wrote:

“Adipose tissue in individuals with obesity may act as a reservoir for more extensive viral spread, with increased shedding, immune activation, and cytokine amplification.”

Then, it was a theory. But now, researchers from Stanford and other research centers have produced evidence that this is true. The virus seems to use adipose tissue as reservoir for infection. It also may serve as a tool for kicking off inflammation that causes much of the damage from this virus.

This finding is not exactly a bolt from the blue. But right now, it’s only a pre-print and peer review is not complete. If the findings hold up under scrutiny, though, it helps explain why obesity may lead to bad outcomes with COVID-19.

Adipose Tissue: A Big, Vulnerable Endocrine Organ

Many commonly think of obesity as a mere physical characteristic. In that way of thinking, fat tissue is inert – just a place where the body stores extra energy. Of course, that’s utterly false. For someone living with significant obesity, adipose tissue is the biggest organ in their body. And it’s a very active part of the immune system. When someone has obesity, their fat tissue is a source of systemic inflammation. That’s exactly why obesity contributes to so many other chronic diseases like diabetes, heart disease, liver disease, and cancer.

Catherine Blish was one of two senior authors on this research. She and her colleagues demonstrated that SARS-CoV-2 could directly infect adipose tissue and generate a cascade of inflammation. She explains why this is important:

“This could well be contributing to severe disease. We’re seeing the same inflammatory cytokines that I see in the blood of the really sick patients being produced in response to infection of those tissues.”

An Unnecessary Risk

After old age, untreated obesity is perhaps the biggest biological risk factor for bad outcomes, including death. It can more than double the risk of death for younger patients with severe obesity.

Obesity is a chronic disease. That means it’s not really curable, but it is totally manageable. The most effective treatment is bariatric surgery and the available evidence suggests that it cuts the risk for severe outcomes and death by as much as 85 percent. Other options can also be quite effective for reducing the health effects of obesity.

So it is absurd to put so many restrictions on the access to care for obesity in the face of this pandemic. It simply leaves people vulnerable if SARS-CoV-2 can target and exploit fat tissue to do its damage.

Click here for the study of SARS-CoV-2 and adipose tissue, here, here, and here for further perspective.

Novel Coronavirus SARS-CoV-2, scanning electron micrograph by NIAID, licensed under CC BY 2.0.

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December 9, 2021