A research team has discovered a new type of immune cell that is found in the adipose tissue and seems to contribute to the chronic inflammation associated with aging, called in jargon inflammaging (a crasis from English inflammation + aging).

The good news is that there is another type of immune cell that seems to be able to keep this inflammation under control. The details are published on Nature Aging.

The role of macrophages. Normally inflammation is the way in which the immune system responds to wounds or infections: when we age, however, this process gradually increases and becomes chronic (even if, according to a recent study we have spoken of, this seems to happen only in those who live in industrialized countries). Among the cells that help to regulate inflammaging there are some types of macrophages, white blood cells that are found in the adipose tissue and have the task of engulfing pathogens and cellular fragments.

To understand more, the researchers conducted tests on young and elderly mice, analyzing their adipose tissue around the organs. They then divided the macrophages into different categories by detecting 13 types. Among these, they captured their attention a type of macrophage so far unknown that was not present in young mice, but only in the elderly and expressed high levels of inflammatory markers and factors associated with inflammaging: what is not clear is how these macrophages, which contribute to inflammation, develop.

A tool against inflammaging? The authors then analyzed more deeply the role of another type of macrophages that are near the nerves in the adipose tissue and which decrease with age only in female mice. By eliminating them in young specimens, they saw that their decrease caused greater inflammation and alterations in the metabolic processes of the adipose tissue.

So this type of cells associated with nerves help to keep inflammaging at bay and regulate the adipose tissue. One of the next questions to ask, concludes Miriam Merad, immunologist not involved in research, is whether macrophages populations can be restored or maintained for therapeutic purposes, to limit inflammaging and metabolic dysfunctions.