ESM1 and endothelial dysfunction: In addition, recent studies highlighted that endothelial dysfunction plays a significant role in CKD; in particular, endocan, a soluble proteoglycan secreted by endothelial cells and considered a novel biomarker of endothelial dysfunction, has been shown to contribute to various renal diseases such as diabetic nephropathy and autosomal dominant polycystic kidney disease (10).