SPP1 and atherosclerosis: Notably, this SPP1-CD44/integrin axis of cellular crosstalk is not restricted to muscular tissues; it is also operational in the coronary perivascular adipose tissue (PVAT) of patients with atherosclerosis, where SPP1+ macrophages similarly exacerbate local fibrosis (187), revealing a common trans-tissue mechanism of macrophage-driven fibrosis.