Senescent Macrophages Emerge as Central Drivers of Skeletal Aging

A comprehensive review in Ageing Research Reviews pinpoints senescent macrophages as central hubs driving skeletal aging. Unlike typical immune cells that die or get cleared, these zombie-like macrophages accumulate in bone and muscle tissue with age, secreting inflammatory factors that disrupt the local tissue environment (niche). The review synthesizes evidence showing these cells contribute to both osteoporosis and sarcopenia by interfering with bone-building osteoblasts and muscle regeneration. What makes this particularly significant is the dual role: senescent macrophages not only damage local tissues but also release factors that amplify systemic inflammation, potentially affecting multiple organ systems. This positions them as high-value therapeutic targets—clearing senescent macrophages with senolytics could potentially address multiple age-related skeletal problems simultaneously. The framework helps explain why skeletal aging involves coordinated decline across bone and muscle rather than isolated tissue breakdown, and suggests that immunosenescence in tissue-resident macrophages may be as important as stem cell exhaustion in driving musculoskeletal frailty.