Abstract
Cardiac fibrosis is a major component of heart failure (HF) and develops when reparative wound healing becomes chronic, leading to excessive extracellular matrix accumulation. Cardiac fibroblasts (CFs), the main regulators of matrix remodeling, are heterogeneous in developmental origins, regional localizations, and activation states. This diversity determines whether tissue repair resolves normally or progresses into maladaptive scarring that disrupts myocardial structure and function after injuries. Recent single-cell and spatial transcriptomic studies show that CFs exist in distinct yet interrelated molecular states in murine models and human cardiac tissue with specialized roles in matrix production, angiogenesis, immune signaling, and mechanical sensing. These insights redefine cardiac fibrosis as a dynamic and context-dependent process rather than a uniform cellular response. Although CFs are promising targets for preventing HF progression and enhancing cardiac remodeling, translation into effective therapies remains limited by the unclear heterogeneity of pathological fibroblasts, the lack of distinctive CF markers, and the broad activity of fibrogenic signaling pathways. In this review, we discuss the dynamics of CF activations during the development and progression of HF and assess the underlying pathways and mechanisms contributing to cardiac dysfunction. Additionally, we highlight the potential of targeting CFs for developing therapeutic strategies. These include nonspecific suppression of fibroblast activity and targeted modulation of the signaling pathways and cell populations that sustain chronic remodeling. Furthermore, we assess regenerative approaches that can reprogram fibroblasts or modulate their paracrine functions to restore functional myocardium. Integrating antifibrotic and regenerative strategies with advances in precision drug discovery and gene delivery offers a path toward reversing established fibrosis and achieving recovery in HF.