SOD1 and cyclic hematopoiesis: Therefore, this observational cohort study was designed to evaluate, as the primary endpoint, the levels ec-SOD in two models of NTIS: (1) patients with chronic kidney disease undergoing haemodialytic treatment that started a short period ago (“acute haemodialytic patients”, AH); and (2) patients who have been undergoing haemodialysis for a longer time period (“chronic haemodialytic patients”, CH).