Inflammatory factors that aggravate COVID-19 may come from adipose tissue

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There is growing evidence that adipose tissue plays a key role in the aggravation of COVID-19. One of the theories under investigation is that fat cells (adipocytes) act as a reservoir for SARS-CoV-2 and increase viral load in obese or overweight individuals.
Inflammatory factors that aggravate COVID-19 may come from adipose tissue

Scientists also suspect that during infection fat cells release into the bloodstream substances that boost the inflammatory reaction triggered by the virus in the organism.

These hypotheses are being investigated by researchers at the University of São Paulo's Medical School (FM-USP) in Brazil under the coordination of Marilia Cerqueira Leite Seelaender, a professor in the Department of Clinical Surgery. Peter Ratcliffe, a professor at the University of Oxford in the UK and one of the winners of the 2019 Nobel Prize for Medicine, is collaborating.

A cytokine storm resulting in systemic inflammation similar to sepsis occurs in some severe COVID-19 patients. We believe these inflammatory factors come from adipose tissue. It's been shown that when adipocytes expand too much, they can cause inflammation throughout the body, even in the brain." Marilia Cerqueira Leite Seelaender, Professor in the Department of Clinical Surgery

The FM-USP group analyzed samples of adipose tissue obtained from autopsies of people who died from COVID-19, and also from patients infected with SARS-CoV-2 who had to be submitted to emergency surgery at the university's hospital for appendicitis or other reasons not related to the viral infection. Preliminary results confirmed that the virus can be found in fat cells, whose membranes are rich in ACE-2, the main receptor used by the virus to invade human cells. The researchers have yet to confirm that once it has invaded adipocytes, it can remain there long enough to replicate inside them.

"It's worth noting that visceral adipocytes [located deep in the abdomen and around internal organs] have much more ACE2 than subcutaneous adipose tissue," Seelaender said. "In addition, they're much more inflammatory. As a result, visceral obesity tends to be even more harmful as far as COVID-19 is concerned."

The preliminary findings also brought to light a change in the…
Emily Henderson, B.Sc.
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