Human Natural Killer Cell

Natural Killer Cells in Obesity and Its Treatment

The natural killers of our immune system – lymphocytes known as natural killer cells – increasingly seem to have a role in the pathophysiology of obesity and in the response to its treatment. Just this week, researchers from Ireland published a study showing that semaglutide for obesity may restore more normal function of these cells.

This is important because scientists understand that these cells don’t function well in persons with obesity. That dysfunction may account, in part, for the increased vulnerability to viral infections and cancer that comes with obesity.

“Natural” Killers

These killer cells are important to our immune systems because they provide a rapid response to viral infections and to the formation of tumors. Unlike most immune cells, they don’t require antibodies to detect and kill these threats to the body. Natural killer cells identify and neutralize threats that other immune cells cannot because they act independently of antibodies and without having to detect major histocompatibility complex antigens on the surface of those threats.

These unique features make natural killer cells indispensable for healthy immune function. They’re known as natural killers simply because they don’t require the activation that other lymphocytes require to do their job.

Restored Peripheral Function

Within fat tissue, these killer cells are more present and more active when a person has obesity. But in the rest of the body, their numbers and their function are suppressed. So Conor De Barra investigated the possibility that anti-obesity therapy with semaglutide might restore more normal function of natural killer cells all over the body. In their small study of 20 patients, they found evidence that it did, concluding:

“The restoration, by GLP-1 therapy, of NK cell functionality in PWO may be contributing to the overall benefits being seen with this class of medication.”

The senior author on this study, Andrew Hogan, will be presenting this research at ECO2023 in Dublin. It will be a session not to miss.

Consistent with Effects of Bariatric Surgery

More than a decade ago, Cristiane Martins Moulin showed that obesity treatment with bariatric surgery could restore better function for natural killer cells. This may be part of the story that explains why obesity related cancers become less common after bariatric surgery. It may also inform our understanding of the observation that COVID risks are lower in people who have had bariatric surgery.

In any event, these are exciting times. The advent of more effective options for obesity treatment not only offers the possibility of better health outcomes now. It also opens the door to better scientific insight into the pathophysiology of obesity. In turn, this will lead to even better prospects for people who live with obesity.

Click here for the research by De Barra et al and here for the Moulin research. For an overview of natural killer cell dysregulation in obesity, click here.

Human Natural Killer Cell, scanning electron micrograph by NIAID, licensed under CC BY 2.0

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May 11, 2023