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DESIGN AND EVALUTATION OF A HEPARIN ADSORBING FILTER FOR APPLICATION IN EXTRACORPOREAL HAEMODIALYSIS

Objective


The main objective of the contract, the prototype of a highly selective heparin-absorbing filter (H.A.F.), has been achieved. This filter may allow the use of membrane dialysers with regional (i.e., confined to the extracorporeal region) heparinization, preventing the occurrence of serious side effects due to increased heparin levels in the patient's blood. It is composed of a reservoir (container) containing rigid beads coated with a biocompatible polysaccharide hydrogel layer, where are grafted macromolecular chains which selectively absorb heparin. The filter combines limited dimensions, its internal volume being about 50 ml, with high efficiency both in terms of heparin-absorbing capacity and heparin-absorbing rate. The bioactive component of the filter appears to be endowed with good hemocompatibility by all in vitro tests. A limited number of animal experiments confirmed the high heparin-absorbing efficiency of the filter, confirming the advisability of further investigations for tuning the device to the needs of the clinical use.
The proposed research is directed on developing a selective de-heparinizing filter for blood, to be used for de-heparinizing blood in patients receiving heparin as an anticoagulant agent to avoid thrombus formation, for instance in extracorporeal circuits.

The problems induced by heparin administration are especially felt by patients undergoing haemodialysis, for whom it represents one the cause of morbidity. It is anticipated that the filter will allow to confine heparin within the extracorporeal circuit by re-adsorbing it just before blood re-enters the patient's body, thus achieving regional heparinization. Previous research had shown that some synthetic hydrogels of poly(amidoamine) structure have very high capability and selectivity in adsorbing heparin from blood. These hydrogels will be grafted onto glass beads entirely coated with biocompatible polysaccharides, in order to join regular shape, optimal size, good mechanical properties and relatively high density.

The key points of the research are:

- Optimizing the filter's design, including development of a mathematical model;

- coating beads with polysaccharides;

- grafting poly(amido-amines) onto the polysaccharide-coated beads;

- studying the heparin-adsorbing properties and the biocompatibility of the beads both in vitro, ex vivo, and in vivo;

- preparing a filter prototype ready for clinical studies.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Università degli Studi di Brescia
Address
Via Branxe 9
25123 Brescia
Italy

Participants (5)

UNIV COIMBRA
Portugal
Address
Dept. De Bioquimica
3049 Coimbra
UNIV GENT
Belgium
Address
Krijgslaan 281 S-4
9000 Gent
UNIV PATRAS
Greece
Address
Riow
26110 Patras
Università degli Studi di Bologna
Italy
Address
Via Massarenti 9
40138 Bologna
Università degli Studi di Milano
Italy
Address
Via Pascal 36
20133 Milano