REN and chronic kidney disease: Surprisingly, despite the state-of-the-art therapeutic and advanced pharmaceutical strategies, such as the uses of angiotensin-converting enzyme inhibitor (ACEI), angiotensin II type I receptor blockade (ARB), direct renin inhibitor (DRI) and good education regarding how to avoid damage of kidney as well as renewed guidelines for CKD precise management, progressive deterioration of kidney function still inevitably occurs in a majority of CKD patients, subsequently progresses into end-stage renal disease (ESRD) in these patients [7–10].