Intradialytic Body Weight Changes and Dialyzer Pore Size as Main Contributing Factors to the Evolution of Beta-2-Microglobulin in Dialysis

Abstract

Cuprophane hemodialysis is associated with an early fall of leukocyte counts and an intradialytic rise in serum β₂-microglobulin (β₂M), in contrast to dialysis with more compatible dialyzers. It has been suggested that these two phenomena may be related. This study sets out to verify this hypothesis by comparing the evolution of leukocyte counts with that of β₂M: (1) during dialysis with 5 dialyzer types with different pore size and/or leukocyte biocompatibility; (2) during first use and reuse of 3 dialyzer types, and (3) during sequential ultrafiltration and dialysis with cuprophane. In first-use dialyses, no relation could be found between changes in leukocyte counts and the evolution of β₂M levels. Reuse of cuprophane and saponified cellulose ester resulted in a marked attenuation of the intradialytic fall in leukocyte counts after 15 min (change in white blood cell count: -72 and -17% for first-use and third-reuse cuprophane, -72 and -23% for saponified cellulose, respectively), but had no influence on the increase in β₂M. Correlation studies of these data revealed that the intradialytic evolution of β₂M was related to membrane pore size and, for membranes with a small pore size, to the intradialytic fluid losses: first-use cuprophane (p < 0.05), saponified cellulose ester (p < 0.001) and hemophane (p < 0.01), and pooled first-use and reuse cuprophane and saponified cellulose ester (p < 0.001). Cuprophane dialysis without ultrafiltration (dialysate Na⁺: 138 and 132 mEq/1) caused a fall in leukocytes, but induced no rise in β₂M. Ultrafiltration with cuprophane either preceding or following dialysis consistently caused a rise in serum β₂M, although a fall in leukocyte counts only occurred in the first case. Our data point away from a relationship between membrane biocompatibility, expressed as changes in leukocyte counts, and β₂M concentration during hemodialysis. The major contributing factors appear to be dialytic fluid losses and membrane pore size.

There Is Insufficient Evidence That Membrane Incompatibility Causes Amyloidosis

“…However, the majority of so-called biocompatible membranes that cause no increase in P2M concentration are at the same time high-flux dialyzers with large pores and/or a capacity to adsorb P2M. If "biocompatible" dialyzers with a pore size similar to that of cuprophane are studied, or if cuprophane is made biocompatible by formaldehyde reuse, the rise in P2M remains identical to first-use cuprophane (9). Sham dialysis (without weight loss) also induces no changes in serum P2M (10).…”

“…Amyloid deposits are largely confined to the musculoskeletal system, but there are a few reports of visceral involvement (7) and of amyloid-matrix renal stones (8). Presenting features include carpal tunnel syndrome, bone cysts, and pathologic bone fractures, destructive arthropathies, tenosynovitis with trigger finger, and spondyloarthropathies (9)(10)(11)(12)(13)(14)(15). As with other amyloid diseases, treatment is unsatisfactory.…”

Serumspiegel und organablagerungen vonΒ 2-mikroglobulin bei dialysepatienten

“…Bemerkenswert in eine Korrelation zum Grad der Niereninsuffizienz und zur Dialysedauer, die m6glicherweise im Zusammenhang mit der zunehmend geringeren Restfunktion und Diurese der Patienten steht. Es konnte auch keine Beziehung zwischen der w/ihrend der Dialyse beobachteten Neutropenie und Granulozytenzerst6rung als Folge der Bioinkompatibilit/it verschiedener Membranen und dem Serum f12 M-Spiegel festgestellt werden; die Wiederverwendung von Membranen war ohne Einflul3 auf die f12 M-Serumkonzentration [39]. Dagegen ist durch in vitro-und in vivo-Untersuchungen entgegen frfiheren Ansichten klar geworden, dab eine vermehrte Bildung durch den Blut-Membrankontakt keine Rolle spielen dfirfte [38].…”