From the start of the pandemic, the coronavirus seemed to target people who were overweight. Patients who were overweight or obese were more likely to develop severe Covid-19 and die.
While these patients often have health conditions that increase their risk, such as diabetes, scientists are increasingly convinced that their vulnerability has something to do with obesity.
Now researchers have found that the coronavirus infects both fat cells and certain immune cells in body fat, causing a harmful defensive response in the body.
Scientist who studies fat cells at UT Southwestern Medical Center in Dallas and was not involved in the research, Dr. “The bottom line is, ‘Oh my god, really, the virus can infect fat cells directly,'” said Philipp Scherer. .
“Not everything that is in oil stays in oil,” he added. It also affects neighboring tissues,” he said.
The research has not yet undergone peer-reviewed or published in a scientific journal, but posted online In October. If the findings are correct, they could shed light not only on why overweight patients are vulnerable to the virus, but also why some young adults who have no other risk become so sick.
The study’s authors suggested that the evidence could point to new Covid treatments that target body fat.
Professor of comparative medicine and immunology at Yale School of Medicine, Dr. “Perhaps this is the Achilles heel that the virus uses to evade our protective immune responses – by hiding here,” said Vishwa Deep Dixit.
The finding is particularly relevant to the United States, which has one of the highest rates of obesity in the world. Most American adults are overweight, and 42 percent have obesity. Black, Hispanic, Native American, and Alaskan Native Americans have higher rates of obesity than white adults and Asian Americans; they, too, were disproportionately affected by the epidemic, and their death rate is roughly double that of white Americans.
“This can contribute to serious illness” D., a professor at Stanford University Medical Center and one of the report’s two senior authors. “Catherine Blish,” she said. “We’re seeing the same inflammatory cytokines that I see in the blood of really sick patients, being produced in response to infection of these tissues.”
Body fat used to be considered inert, a type of storage. But scientists now know that tissue is biologically active, producing hormones and immune system proteins that act on other cells, and promoting a low-grade state of inflammation even in the absence of infection.
Inflammation is the body’s response to an invader, and sometimes it can be so severe that it can be more harmful than the infection that triggered it.
Adipose tissue is mostly composed of fat cells or adipocytes. It also contains a variety of immune cells, including preadipocytes that mature into fat cells and a type called adipose tissue macrophages.
Dr. Blish, along with colleagues in Stanford, Germany and Switzerland, conducted experiments to see whether adipose tissue from bariatric surgery patients could be infected with the coronavirus and followed how various cell types responded.
The scientists found that the fat cells themselves can become infected, but not so much inflammation. But some immune cells called macrophages can also become infected and develop a strong inflammatory response.
Even weirder, pro-adipocytes were not infected but contributed to the inflammatory response. (Scientists have not studied whether certain variants are more disruptive in this regard than others.)
The research team also obtained adipose tissue from the bodies of European patients who died from Covid, and discovered the coronavirus in fat near various organs.
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Dr. The idea that adipose tissue can act as a reservoir for pathogens is not new, Dixit said. Body fat is known to harbor many, including HIV and the flu virus.
The coronavirus appears to be able to evade the immune defenses of body fat, which are limited and unable to deal with it effectively. And obese people can have too much body fat.
Cardiology professor Dr. David Kass said that a man whose ideal weight is 170 pounds but weighs 250 pounds carries a significant amount of fat where the virus can “hang” and multiply, triggering a devastating immune system response. John Hopkins.
Dr. “If you’re really very obese, fat is the single largest organ in your body,” Kass said.
The coronavirus “can infect that tissue and actually stay there,” he said. “Whether it hurts or kills you or at best, a place to empower yourself – it doesn’t matter. It kind of becomes a reservoir.”
As the inflammatory response snowballs, cytokines trigger further inflammation and the release of additional cytokines. “Like a perfect storm,” he said.
Dr. Blish and colleagues speculated that infected body fat may even contribute to “long Covid,” a condition that describes troublesome symptoms such as fatigue that persists for weeks or months after an acute attack.
The data also shows that Covid vaccines and treatments may need to take into account patient weight and fat stores.
“This article is another wake-up call for the medical profession and public health to take a deeper look at the problems of overweight and obese individuals and the treatments and vaccines we give them,” said Barry Popkin, professor of nutrition. The University of North Carolina at Chapel Hill investigated the high risk Covid poses for those with obesity.
Dr. “We continue to document the risk they have, but we still don’t address that,” Popkin said.