High TARC plasma levels confer protection to long living individuals by inducing M2 profile

A way to delay aging and the related low-grade chronic inflammatory state is to study the model of positive physiology such as the Long-Living Individuals (LLIs). Our recent studies have shown higher levels of the host defense BPI Fold-Containing Family B Member 4 (BPIFB4) protein in the LLIs' blood. Notably, BPIFB4 has been shown to influence monocytes typesetting and M2 anti-inflammatory phenotype (CD206+CD163++) macrophages skewing. According to the role of a complex cytokine milieu in guiding the macrophage polarization, here we found that circulating concentrations of thymus and activation regulated chemokine (TARC)/CCL17 and small-inducible cytokine B10 (IP-10)/CXCL10) cytokines, were additionally associated with the LLIs' state. In a differentiation process in vitro, the addition of LLIs' plasma to the cell culture medium, enhanced the ability of monocytes, either from LLIs or controls, to acquire a M2 phenotype. Interestingly, a neutralizing antibody against TARC blunted the M2 skewing effect of the LLIs' plasma. Collectively, these data indicate that exceptional longevity may associate with a peculiar anti-inflammatory myeloid profile responsible for improved reparative processes and reduced inflammatory status mediated in part by TARC and M2 generation.