Matrifibrocytes Redefine Cardiac Fibrosis: From Terminal Differentiation to Translational Modulation.

Cardiac fibrosis is increasingly recognized as a dynamic program that resolves into a terminal fibroblast fate, the matrifibrocyte, rather than a persistent myofibroblast state. Lineage-tracing and single-cell studies reveal that matrifibrocytes arise from activated myofibroblasts during late scar maturation, lose α-SMA and proliferative capacity, and adopt a cartilage-like ECM program (e.g., Comp, Chad, Thbs4, Sfrp2). Functionally, they stabilize collagen architecture, sustain tensile strength and shape an immune-quiescent, angiogenesis-restrained microenvironment. We synthesize evidence suggesting that TGF-β restraint (e.g., Smad7), matrix mechanics (YAP/TAZ), Wnt attenuation (Sfrp2), Comp-Notch3 feedback, and Thbs4-Atf6α ER-stress adaptation converge to establish or maintain this terminal state. We further summarize disease contexts beyond infarction, including pressure overload and valvular disease, where matrifibrocyte-like programs emerge and may contribute to chronic stiffening. Finally, we outline translational strategies that either accelerate matrifibrocyte maturation to secure scars after acute injury or reset terminal states via pharmacology or direct reprogramming to regress fibrosis. Framing matrifibrocytes as an adjustable endpoint reconciles structural integrity with functional recovery and highlights actionable checkpoints for precision anti-fibrotic therapy.