Developmental processes in ageing: the role of growth regulation.

The underlying causes of ageing remain elusive, as evidenced by the numerous coexisting theories attempting to explain its origin and progression. Developing a robust theoretical framework will not only improve our understanding of this fundamental biological process but also guide the design of interventions targeting the ageing process. Here, we revisit the hypothesis originally proposed by Bidder that the growth-restriction processes-responsible for suppressing growth during development and establishing adult body size-remain active throughout adulthood, potentially acting as a primary driver of ageing. We explore how persistent growth suppression can induce ageing phenotypes, such as organ atrophy and degeneration. Furthermore, we examine supporting observations from comparative studies and experiments in model organisms and address the current limitations of this model, with the expectation that this framework will be further developed and assessed in future research. This article is part of the theme issue 'Developmental circuits in ageing'.