The Stagnant-Starvation-Building (SSB) Cycle: A Novel In Vitro Protocol for Induced Cellular Rejuvenation and Autophagic Repair

The conceptual paradigm of cellular aging and replicative senescence has undergone a profound and highly necessary transformation over the past decade. Historically, the phenomenon of cellular senescence was viewed almost strictly through the lens of the telomere hypothesis and the Hayflick limit, a framework positing that somatic cells possess a rigid, finite replicative capacity governed by the gradual, inevitable attrition of telomeric DNA during successive rounds of mitosis. Under this classical model, aging at the cellular level was considered a passive accumulation of genomic damage, oxidative stress, and a mechanical wearing down of genetic material that ultimately culminated in an irreversible cessation of the cell cycle. However, contemporary advancements in evolutionary biology, molecular biogerontology, and the study of extremophile organisms have revealed a far more complex reality. The aging of mammalian cells, particularly primary human diploid fibroblasts (HDFs), is not merely a passive degradation but an active, highly regulated, and programmable epigenetic state.