The arterial vasculature is the second most frequently calcified structure in the human body after the skeleton. Calcification of the aorta and aortic valves occurs in most individuals in westernized societies with advancing age, with abdominal aortic calcification generally preceding ascending thoracic aortic disease. In cardiac valves and the thoracic aorta, however, calcification often arises earlier in common disease contexts characterized by metabolic, mechanical, or inflammatory injury (eg, metabolic syndrome, chronic kidney disease, irradiation). In these settings, calcification frequently involves the arterial media as a histoanatomic feature, and is associated with accelerated neurocognitive decline and increased cardiovascular mortality, reflecting a form of precocious aging. The term arteriosclerosis was coined nearly 2 centuries ago to describe the calcium-mediated hardening of the aorta and conduit arteries observed at autopsy with aging. However, much of our understanding of the causes, characterization, and consequences of aortic calcium deposition has emerged only within the past decade. Features of disease biology, including engagement of innate immunity, senescence (inflammaging), and ectopic activation of osteogenic mechanisms, are consistently revealed. In this article, we briefly review the burgeoning literature, highlighting recent advances in clinical and discovery science with translational implications. Given the current trajectory, after 2 centuries of disease recognition, the next decade of innovation promises meaningful progress toward effective medical treatments to prevent and treat the clinical consequences of calcific aortopathy.

Peripheral artery disease (PAD) and its severe form, chronic limb-threatening ischemia (CLTI), significantly impair blood flow to the lower extremities, affecting millions of adults globally. Intramuscular adipose tissue (IMAT) and fibrosis accumulation distinguish patients with CLTI from those with mild PAD, suggesting a role in CLTI pathobiology. However, the functional consequences of IMAT in CLTI remain unclear. We compared gastrocnemius muscle samples from patients with PAD/CLTI, those with intermittent claudication, and non-PAD individuals. We analyzed bulk RNA sequencing, proteomic, lipidomic, and single-cell/nucleus RNA sequencing datasets. Additionally, we used murine models of hindlimb ischemia with genetic manipulation of Pparγ, a key adipogenic transcription factor, specifically in fibroadipogenic progenitor cells, the cellular source of IMAT, to modulate IMAT formation and assessed the impact on limb function and pathology. Patients with CLTI exhibited significantly elevated expression of adipogenic genes and proteins in muscle specimens when compared with non-PAD controls. Murine models showed that increasing IMAT formation significantly worsened ischemic limb muscle strength and work output. In contrast, preventing IMAT formation significantly improved ischemic limb muscle strength and work output. These findings were consistent across both male and female mice, although females had a greater tendency to form IMAT compared with male mice. IMAT accumulation is a key determinant of limb function in PAD/CLTI. Our studies demonstrate that targeting IMAT formation could improve limb function in mice with experimental PAD. Together, these findings suggest that developing strategies to limit or reduce IMAT may improve limb function and walking performance in patients with PAD/CLTI, providing a novel therapeutic avenue to address a critical unmet need.