Senescence is a cellular stress response triggered by diverse stressors, including oncogene activation, where it serves as a bona-fide tumour suppressor mechanism. Senescence can be transmitted to neighbouring cells, known as paracrine secondary senescence. Secondary senescence was initially described as a paracrine mechanism, but recent evidence suggests a more complex scenario involving juxtacrine communication between cells. In addition, single-cell studies described differences between primary and secondary senescent end-points, which have thus far not been considered functionally distinct. Here we discuss emerging concepts in senescence transmission and heterogeneity in primary and secondary senescence on a cellular and organ level.

衰老是一种由多种应激源触发的细胞应激反应，包括癌基因激活，它充当真正的肿瘤抑制机制。衰老可以传递到邻近细胞，称为旁分泌继发性衰老。继发性衰老最初被描述为旁分泌机制，但最近的证据表明更复杂的情况涉及细胞之间的近分泌通讯。此外，单细胞研究描述了主要和次要衰老终点之间的差异，但迄今为止尚未被认为在功能上存在差异。在这里，我们讨论细胞和器官水平上衰老传播和原发性和继发性衰老的异质性的新兴概念。