Does the "bystander effect" affect the rate of aging?
By Shubhankar Kulkarni on Jul 28, 2020
Continuous exposure to senescent cells induces cell senescence in intact bystander fibroblasts, spreading senescence towards their neighbors in vitro and, possibly, in vivo. The underlying mechanism of this bystander effect is probably the pro-oxidant and pro-inflammatory signals (especially, reactive oxygen species) from primary senescent founder cells triggering DNA damage and premature senescence in surrounding primary cells. This may contribute to the increasing frequency of senescent cells with age and to the impact senescent cells may have upon their environment.
However, whether the bystander effect affects the rate of aging is not known.
Application: Elimination of senescent cells attenuates tissue inflammation,  probably due to reduced secretion of the senescent cells, leading to suppression of the bystander effect and slowdown of damage accumulation. If the inhibition of the bystander effect reduces the rate of aging, that can be a therapeutic opportunity.
 Nelson G, Wordsworth J, Wang C, Jurk D, Lawless C, Martin-Ruiz C, et al. A senescent cell bystander effect: senescence-induced senescence. Aging Cell [Internet]. 2012 Apr;11(2):345–9. Available from: http://doi.wiley.com/10.1111/j.1474-9726.2012.00795.x
 Xu M, Palmer AK, Ding H, Weivoda MM, Pirtskhalava T, White TA, et al. Targeting senescent cells enhances adipogenesis and metabolic function in old age. Elife [Internet]. 2015 Dec 19;4. Available from: https://elifesciences.org/articles/12997
 Baker DJ, Childs BG, Durik M, Wijers ME, Sieben CJ, Zhong J, et al. Naturally occurring p16Ink4a-positive cells shorten healthy lifespan. Nature [Internet]. 2016 Feb 3;530(7589):184–9. Available from: http://www.nature.com/articles/nature16932