Exosomes represent an evolutionarily conserved signaling pathway which can act as an alarming mechanism in responses to diverse stresses, e.g. chronic inflammation activates the budding of exosomal vesicles in both immune and non-immune cells. Exosomes can contain both pro- and anti-inflammatory cargos but in chronic inflammation, exosomes mostly carry immunosuppressive cargos, e.g. enzymes and miRNAs. The aging process is associated with chronic low-grade inflammation and the accumulation of pro-inflammatory senescent cells into tissues. There is clear evidence that aging increases the number of exosomes in both the circulation and tissues. Especially, the secretion of immunosuppressive exosomes robustly increases from senescent cells. There are observations that the exosomes from senescent cells are involved in the expansion of senescence into neighbouring cells. Interestingly, the age-related exosomes contain immune suppressive cargos which enhance the immunosuppression within recipient immune cells, i.e. tissue-resident and recruited immune cells including M2 macrophages, myeloid-derived suppressor cells (MDSC), and regulatory T cells (Treg). It seems that increased immunosuppression with aging impairs the clearance of senescent cells and their accumulation within tissues augments the aging process.

外泌体代表了一种进化上保守的信号通路，它可以作为应对各种压力的警报机制，例如慢性炎症激活免疫和非免疫细胞中外泌体囊泡的出芽。外泌体可以包含促炎和抗炎物质，但在慢性炎症中，外泌体主要携带免疫抑制物质，例如酶和 miRNA。衰老过程与慢性低度炎症和促炎衰老细胞在组织中的积累有关。有明确的证据表明，衰老会增加循环和组织中外泌体的数量。特别是，免疫抑制性外泌体的分泌从衰老细胞中强劲增加。有观察表明，来自衰老细胞的外泌体参与了衰老向邻近细胞的扩展。有趣的是，与年龄相关的外泌体含有免疫抑制物质，可增强受体免疫细胞内的免疫抑制，即组织驻留和募集的免疫细胞，包括 M2 巨噬细胞、骨髓源性抑制细胞 (MDSC) 和调节性 T 细胞 (Treg)。似乎随着衰老而增加的免疫抑制会损害衰老细胞的清除，并且它们在组织内的积累会加剧衰老过程。和调节性 T 细胞 (Treg)。似乎随着衰老而增加的免疫抑制会损害衰老细胞的清除，并且它们在组织内的积累会加剧衰老过程。和调节性 T 细胞 (Treg)。似乎随着衰老而增加的免疫抑制会损害衰老细胞的清除，并且它们在组织内的积累会加剧衰老过程。