DDR2 and heart failure: Moreover, by examining the expression levels of fibroblasts (including POSTN, VIMENTIN and DDR2) and FABP4 in total fibroblasts isolated from the patient’s heart, we observed elevated expression levels of fibroblast markers, including POSTN, VIMENTIN, DDR2, and FABP4, in the heart failure group compared to the control group (Fig. 2j and Supplementary Fig. 4d).