Mast cells as biomarkers of inflamm-ageing

Most mechanisms of ageing are believed to be more or less associated with inflammation. With age, a unique form of chronic inflammation develops which is termed as “inflamm-ageing”. The mechanisms of this process are still not fully clear due to the lack of reliable assessment criteria. Immune system is among those involved in accelerating age-related changes in the body. It also directly participates in the process of inflammation. In its pathogenesis, the reaction of mast cells may be of great importance. The role of mast cells in tissue remodeling deserves special attention, since the latter event is among the main features associated with ageing. Hence, the “inflamm-ageing” is considered a sufficient indicator of ageing, and the mast cells could provide biomarkers of this process. In order to test the proposed hypothesis, the present study was conducted to determine age-related morpho-functional changes in mast cell populations in various organs in rats. Some morpho-functional parameters of mast cells (number, synthetic and functional activity, degree of maturation) in different animal organs were evaluated in male Wistar rats of different ages (4 months and 2 years). We have found the age-dependent changes upon examination of thymus, adrenal glands, and skin, i.e., a decrease in the number of mast cells and their synthetic capacity, along with significantly increased functional activity. In the stomach, small and large intestines, at the constant number of mast cells, we revealed a decrease in their synthetic ability, and increased functional activity. These changes were accompanied by enlargement of blood vessels in the studied organs. Liver is the only organ which did not exhibit any changes in mast cell populations with age. The detected changes in mast cell populations may play an important role in formation of “inflamm-ageing” events, which accompany the ageing processes, because these cells are an integral component of inflammatory response. The progression of “inflamm-ageing” leads to accumulation of cytokines and pro-inflammatory mediators in tissues, which, in turn, activate the mast cells. At the same time, increased degranulation of mastocytes may promote the process of “inflamm-ageing”. The oberved mutual influence of mast cells and “inflamm-ageing” makes it possible to consider mastocytes as potential candidates for searching the biomarkers in “inflamm-ageing”.