Reply: Could the Interplay Between Macrophages and Fibroblasts Drive Extracellular Matrix Dynamics in End-Stage Heart Failure?

Contrary to the author’s suggestion that there is “no extensive inflammation or fibrosis” observed in our study, our values were 20 to 30 times greater than normal tissue. By looking at the change in a single variable, hemodynamic loading, we sought to narrow our focus to uncover pathways that could be the basis of further hypothesis testing. Because continuous-flow LVADs rapidly and consistently improve cardiac hemodynamics, lower neurohormone levels, and decrease wall stress, we were surprised to find no differences in histologic collagen after long-term mechanical unloading.