title: Cellulose acetate beads activate the complement system but inactivate the anaphylatoxins generated.
abstract: The generation of anaphylatoxins, particularly C5a, is important in extracorporeal circulation therapies such as granulocyte/monocyte apheresis, which activates the complement system and elevates C5a levels. However, no side effects of granulocyte/monocyte apheresis using cellulose acetate beads have been reported. To investigate the mechanism of complement activation, we prepared plasma from cellulose acetate bead-treated blood (P-CAB) and compared it with zymosan-activated plasma (ZAP). Anaphylaxis activity was measured by skin test, and the activity of carboxypeptidase, which inactivates C5a, was measured by colorimetric assay. Pro-carboxypeptidase R and neutrophil elastase concentrations were measured by enzyme-linked immunosorbent assay. Although C5a was generated in P-CAB, the anaphylaxis activity of P-CAB was lower than that of ZAP. Carboxypeptidase activity and pro-carboxypeptidase R levels were suppressed in P-CAB, but not in ZAP. Furthermore, neutrophil elastase levels increased in P-CAB. The decreases in carboxypeptidase activity and inactivation of anaphylatoxin were inhibited by a neutrophil elastase inhibitor. These results suggest that cellulose acetate beads initiate the activation of carboxypeptidase R via elastase release, thereby inducing the inactivation of anaphylatoxin.
authors.affiliation: Department of Environmental and Preventive Medicine, Hyogo College of Medicine, Nishinomiya, Japan. ytakeda@hyo-med.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ohba
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ueno
authors.forename: Abbi R
authors.initials: AR
authors.lastname: Saniabadi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Wakabayashi
mesh_terms: D000706:Anaphylatoxins / Q000378:metabolism*; D000818:Animals; D002268:Carboxypeptidases / Q000378:metabolism; D002482:Cellulose / Q000031:analogs & derivatives* / Q000494:pharmacology; D003167:Complement Activation / Q000187:drug effects*; D005112:Extracorporeal Circulation; D005260:Female; D006801:Humans; D019272:Leukocyte Elastase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010949:Plasma / Q000187:drug effects; D011817:Rabbits; D015054:Zymosan / Q000494:pharmacology*
chemical_list: D000706:Anaphylatoxins; C005062:acetylcellulose; D002482:Cellulose; D015054:Zymosan; D002268:Carboxypeptidases; D019272:Leukocyte Elastase