Beta-2-Microglobulin Generation Rate and Clearance Rate in Maintenance Hemodialysis Patients

Abstract

We analyzed the rebound pattern of plasma β<sub>2</sub>-microglobulin (β<sub>2</sub>-m) concentration from 4 h after completion of hemodiafiltration until the start of the next treatment according to the one-pool β<sub>2</sub>-m kinetic model so as to determine β<sub>2</sub>-m generation rate and whole-body β<sub>2</sub>-m clearance. Next, we obtained the whole renal β<sub>2</sub>-m clearance as the product of renal creatinine clearance and the glomerular sieving coefficient of β<sub>2</sub>-m. Then, extrarenal β<sub>2</sub>-m clearance was calculated as the difference between whole-body β<sub>2</sub>-m clearance and whole renal β<sub>2</sub>-m clearance, and renal β<sub>2</sub>-m clearance due to tubular absorption was taken to be the difference between whole renal β<sub>2</sub>-m clearance and renal β<sub>2</sub>-m clearance due to urinary excretion. The results showed that the β<sub>2</sub>-m generation rate was virtually the same for all patients and that the higher the patients and that the higher the patients’ plasma β<sub>2</sub>-m concentration was, the lower was the whole-body β<sub>2</sub>-m clearance. Moreover, in the present study, an inverse correlation was found between the following respective factors: plasma β<sub>2</sub>-m concentration and whole renal β<sub>2</sub>-m clearance; plasma concentration and renal clearance due to tubular absorption; plasma concentration and renal clearance due to urinary excretion. However, there was no correlation between plasma β<sub>2</sub>-m concentration and extrarenal β<sub>2</sub>-m clearance. The findings indicate that the variation of plasma β<sub>2</sub>-m concentration with the individual patient is solely attributable to the variation in residual renal function in terms of β<sub>2</sub>-m elimination.