For decades, chronic low-grade inflammation in older adults was treated as a background condition — an inevitable consequence of aging with modest clinical relevance. A major review in Nature Reviews Molecular Cell Biology reframes this assumption, presenting inflammaging and clonal hematopoiesis of indeterminate potential (CHIP) as locked in a dangerous amplifying cycle that accelerates cardiovascular disease, hematological cancers, and broad systemic decline.
CHIP arises when a single somatically mutated hematopoietic stem cell (HSC) undergoes clonal expansion, eventually accounting for a substantial fraction of circulating leukocytes. The most commonly mutated genes — including DNMT3A, TET2, and ASXL1 — are epigenetic regulators. In normal HSCs, the chronic inflammatory microenvironment characteristic of aging impairs self-renewal capacity and accelerates functional exhaustion. Paradoxically, CHIP-mutant HSCs appear largely resistant to this inflammaging-induced decline and actually exploit inflammatory signals to gain selective expansion advantages over their normal counterparts. The mutant clones then secrete pro-inflammatory cytokines, deepening the inflammatory environment and accelerating their own dominance — a feedback loop the review terms the CHIP-inflammaging interplay.
This bidirectional relationship has significant implications for understanding aging as a systemic, self-reinforcing process rather than a collection of independent organ failures. CHIP prevalence rises sharply after age 60, reaching roughly 10–20% in those over 70, making this interplay relevant to a large aging population. The review's translational framing — identifying potential therapeutic targets within the CHIP-inflammation axis, such as IL-6 and IL-1β signaling — is clinically promising, though intervention evidence in humans remains early-stage. A critical limitation is that most mechanistic insights derive from mouse models and observational cohort studies; causal directionality in humans is still being established. Nevertheless, as a synthesis of converging molecular, cellular, and epidemiological evidence, this review represents a meaningful framework shift for longevity medicine, suggesting that targeting the CHIP-inflammaging loop could eventually reduce multiple age-related disease risks simultaneously.