We also suggested that CB1 is expressed by initially injured cells and by cells involved in synthesizing extracellular matrix proteins similarly to what is seen with the expression of DDR1, another important pathway in renal fibrosis.47 The high tubular expression of CB1 that we observed during CAD, using the exact same primary antibody and protocol that was previously used in the other types of CKD,18 enhances this hypothesis and strongly suggests a key role of CB1 in tubules in the IF/TA process. The gene discussed is DDR1; the disease is renal fibrosis.