The role of the fibroblast in cardiorenal syndrome

The diversity of fibroblasts across different organs, and within the same structures, means that their role in both health and disease is manifold. This review focuses on their job in the heart and kidney, specifically during the course of cardiorenal syndrome (CRS). During CRS, there is a complex bidirectional interplay between the two body systems whereby the failure of one drives the decline of the other. These effects manifest by a response that leads to the deposition of fibrotic tissue, attributable to fibroblast dysfunction. Fibroblasts in themselves provide essential functions within organs, which are determined by the specific identity of their subtype. During disease, fibroblast function is further constrained and directed by the niches that form at the sites of injury. This review delves into the origins of fibroblasts in the heart and kidney, their functions in each tissue, and the processes and stressors whereby they become activated to form myofibroblasts. We discuss tools that can be used to study the phenomenon of fibroblast activation in vitro and in human studies and, finally, what therapeutic possibilities there may be in the future.