title: Biocompatibility evaluation of polyamide hemofiltration.
abstract: BACKGROUND
  Postdilution hemofiltration with a polyamide membrane is a renal replacement technique widely used, but very little information is available regarding the biocompatibility of this treatment. In this paper we report the results of an acute study of the biocompatibility of polyamide hemofiltration.
  
  
  METHODS
  Complement activation such as C3a and C5a Des Arg (RIA), granulocyte degranulation like alpha 1 elastase intradialytic increase (ELISA) and the expression of high affinity membrane receptors for IL-2 (anti-TAC) were determined. Beta 2-microglobulin (RIA) intradialytic decrease, as well as its convective removal, was evaluated. The nature of protein layer adsorbed onto the polyamide membrane, at the end of the dialytic session was investigated with a new immunohistochemical technique. Cell-associated cytokine concentration (like IL-1 beta and IL-1Ra - ELISA) was determined on mononuclear cell lysates.
  
  
  RESULTS
  A low degree of complement activation was detected with the polyamide membrane when data were adjusted for hemoconcentration and for 1 m2 of membrane surface area. An important convective removal not only of Beta 2-microglobulin (258+/-20 mg/session), but also of the activated anaphylatoxins (225+/-76 ng/ml for C3a and 22.5+/-4 ng/ml for C5a) was revealed. A marked deposition of all coagulation factors with no detectable amount of immunoglobulins and complement factors was revealed on the polyamide membrane at the end of the dialytic session. No intradialytic (for IL-1beta) (from 14. 1+/-3.0 to 13.5+/-2.9 pg/2.5 x 10(6) cell) and interdialytic (for IL-1Ra) (from 4572+/-1076 to 5408+/-615 pg/2.5 x 10(6) cell) cell-associated cytokine expression was induced by hemofiltration.
  
  
  CONCLUSIONS
  Polyamide hemofiltration is a highly biocompatible technique due to the use of a synthetic membrane with a sterile reinfusion fluid and the convective removal of the activated anaphylatoxins and Beta 2-microglobulin.
authors.affiliation: Department of Internal Medicine, University of Pisa, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Panichi
authors.forename: A M
authors.initials: AM
authors.lastname: Bianchi
authors.forename: B
authors.initials: B
authors.lastname: Andreini
authors.forename: L
authors.initials: L
authors.lastname: Casarosa
authors.forename: M
authors.initials: M
authors.lastname: Migliori
authors.forename: S
authors.initials: S
authors.lastname: De Pietro
authors.forename: D
authors.initials: D
authors.lastname: Taccola
authors.forename: L
authors.initials: L
authors.lastname: Giovannini
authors.forename: R
authors.initials: R
authors.lastname: Palla
mesh_terms: D000328:Adult; D000368:Aged; D000706:Anaphylatoxins / Q000032:analysis / Q000302:isolation & purification; D001672:Biocompatible Materials; D003167:Complement Activation; D015926:Complement C3a / Q000032:analysis; D015937:Complement C5a, des-Arginine / Q000032:analysis; D016207:Cytokines / Q000032:analysis; D005260:Female; D006440:Hemofiltration / Q000295:instrumentation*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D009757:Nylons; D011506:Proteins / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000032:analysis; D001613:beta 2-Microglobulin / Q000032:analysis / Q000302:isolation & purification
chemical_list: D000706:Anaphylatoxins; D001672:Biocompatible Materials; D015937:Complement C5a, des-Arginine; D016207:Cytokines; D008567:Membranes, Artificial; D009757:Nylons; D011506:Proteins; D015375:Receptors, Interleukin-2; D001613:beta 2-Microglobulin; D015926:Complement C3a