The Interaction of Senescent Cells and Macrophages in Fibrosis

The interaction between senescent cells and macrophages is of great importance to wound healing. Differences in the behavior of these two cell types appear critical to proficient regeneration in species like salamanders versus poor regeneration and scarring in mammals. Fibrosis is a malfunction of tissue maintenance and regeneration, in which excessive scarring takes place, disrupting tissue function and structure. This too is connected to the presence and behavior of senescent cells and macrophages. In old individuals, there is a background of raised inflammatory signaling and a growth in lingering senescent cells. One way to look at fibrosis is that this chronic inflammation and persistence of senescent cells interferes in the normal signaling between transient senescent cells and macrophages in regeneration and tissue maintenance, leading to pathological outcomes. Senescent cells are attractive candidates as drivers of age-related organ dysfunction. They are consistently seen in diseased and older tissues when compared with healthy age-matched controls, actively secreting pro-inflammatory and pro-fibrotic molecules capable of driving further (paracrine) senescence and propagating on-going tissue damage. This is potentially because they secrete pro-inflammatory cytokines in the senescence-associated secretory phenotype (SASP) which modify the surrounding environment. Macrophages contribute to clearance of senescent cells by phagocytosis. This activity declin...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs