Immune cells in fat, those designed to protect against cold temperatures, eventually turn against its host during aging.
- With age, adipose tissue loses innate immune cell group 2 lymphoid cells (ILC2) that restore body heat in the presence of cold temperatures.
- Their stimulation surprisingly makes them even less tolerant of cold temperatures.
Our body fights the existential threat of cold with the ability to generate heat from fat stored in the body. With age, sensitivity to cold, but also inflammation and metabolic problems can lead to a multitude of chronic diseases. And that would be the fault of the immune cells present in the fat which are designed to protect us from cold temperatures. This is the conclusion of a study published on 1er september in the magazine Cell Metabolism.
When the organism turns against its host
Researchers conducted studies on mice to better understand the mechanism that makes older people more sensitive to cold. They found the fatty tissue of older mice loses innate immune cell group 2 (ILC2) lymphoid cells that restore body heat in the presence of cold temperatures. They also realized, not without amazement, that stimulating the production of new ILC2 cells in aging mice actually makes them more prone to cold-induced death. “What’s good for you when you’re young can harm you as you get older”, summarized Vishwa Deep Dixit, co-author of the study.
When scientists introduced a molecule that stimulates the production of ILC2 into aging mice, immune system cells were restored, but the mice were surprisingly even less tolerant of cold temperatures. “The simple assumption is that if we restore something that is lost, then we will also restore life to normal.says Vishwa Deep Dixit. But that’s not what happened. Instead of developing the healthy cells of youth, the growth factor ended up multiplying the bad ILC2 cells that remained in the fat of the old mice..”
Immune cells, agents with multiple functions
However, when the researchers took ILC2 cells from younger mice and transplanted them into older mice, they found that the older animals’ ability to tolerate cold was restored. “Immune cells play a role beyond simple defense against pathogens and help maintain normal metabolic functions for lifesaid Dixit. With age, the immune system has already changed and we must be careful how we manipulate it to restore health to the elderly..”
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