title: Cystatin C: a new marker of biocompatibility or a good marker for the redistribution of LMW proteins during hemodialysis?
abstract: The mechanism(s) behind the larger relative increase of Plasma beta 2 microglobulin (P-beta 2m) than that of Plasma albumin (P-alb) during Cuprophan hemodialysis is disputed. To elucidate this phenomenon P-alb, P-beta 2m (MW 11,800) and Plasma cystatin (P-cC; MW 13,000) an inhibitor of cystein proteinases, were determined before and after a Cuprophan or polysulphone hemodialysis (4-7 hr, QB 200 ml/min) in 30 stable regular dialysis treatment (RDT) patients. Body weight (BW) decreased by 2.5 +/- 1.4% (mean +/- SD). P-alb, P-beta 2m and P-cC increased by 11.4 +/- 14.8%, 15.4 +/- 11.5%, and 22.1 +/- 14.3%, respectively, during Cuprophan dialysis. The relative increase of P-cC was larger than that of P-beta 2m (P less than 0.05) and that of P-alb (P less than 0.02). During polysulphone dialysis BW decreased by 4.1 +/- 1.8%. P-alb, P-beta 2m, and P-cC increased almost equally by 28.1 +/- 18, 26.5 +/- 19.2, and 26.8 +/- 14.4%, respectively. These results are hard to interpret. Is the increase in P-cC a new marker of biocompatibility or does it reflect the true shift of low molecular weight (LMW) proteins between the interstitial and the plasma volume during hemodialysis better than P-beta 2m? In vitro studies indicate that small amounts of both Serum beta 2m (S-beta 2m) and Serum cystatin C (S-cC) are adsorbed to or sieved through the Cuprophan membrane, findings which render the kinetics of LMW proteins during hemodialysis still more complex.
authors.affiliation: Department of Nephrology, University Hospital, Lund, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Thysell
authors.forename: A
authors.initials: A
authors.lastname: Grubb
authors.forename: T
authors.initials: T
authors.lastname: Lindholm
authors.forename: L
authors.initials: L
authors.lastname: Ljunggren
authors.forename: L
authors.initials: L
authors.lastname: Mårtensson
mesh_terms: D001672:Biocompatible Materials; D001798:Blood Proteins; D001835:Body Weight; D002482:Cellulose / Q000031:analogs & derivatives; D055316:Cystatin C; D015891:Cystatins; D006801:Humans; D008567:Membranes, Artificial; D011108:Polymers; D011480:Protease Inhibitors / Q000097:blood*; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis; D013450:Sulfones; D001613:beta 2-Microglobulin / Q000032:analysis
chemical_list: D001672:Biocompatible Materials; D001798:Blood Proteins; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D008567:Membranes, Artificial; D011108:Polymers; D011480:Protease Inhibitors; D012709:Serum Albumin; D013450:Sulfones; D001613:beta 2-Microglobulin; C017662:polysulfone P 1700; D002482:Cellulose; C009865:cuprammonium cellulose