Document Detail


Evaluation of a novel hirudin-coated polyester graft to physiologic flow conditions: hirudin bioavailability and thrombin uptake.
MedLine Citation:
PMID:  9652474     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: Our laboratory has developed methods required to covalently bind recombinant hirudin (rHir) to the surface of polyester vascular grafts. Using alkaline hydrolysis of the polyester surface, carboxyl-binding sites are created on the outer periphery of each fiber. A series of static, in vitro experiments have demonstrated that surface-bound rHir rapidly removes and inhibits activated human alpha-thrombin from the reaction system; however, the performance of this modified graft material under physiologic flow conditions was undefined. METHODS: An in vitro flow loop was used to evaluate structural stability of the 125I-rHir and 131I-albumin covalently bound to the surface of 6 mm interior diameter crimped polyester grafts exposed to either constant flow (n = 4; shear rate, 300 sec(-1)) or pulsatile flow (n = 4; maximum shear rate, 780 sec(-1)) conditions for a 7-day period. In a separate series of experiments, the kinetics of thrombin-rHir interaction were evaluated through perfusion of 125I-rHir-coated grafts (n = 6) with 131I-thrombin for a 27-hour period under constant flow conditions. Identically prepared 125I-albumin-coated grafts (n = 3) were used as controls. RESULTS: Results of the stability experiments were independent of flow conditions, demonstrating moderate loss of both proteins, with rHir and albumin losses of 52.1% and 19.9% under constant flow and 49.1% and 21.6% under pulsatile flow, respectively. With results comparable with those of previous static experiments, rHir-coated grafts were significantly more effective at removing thrombin from the perfusion stream with 131I-thrombin binding densities of 3.08 +/- 0.61 and 0.64 +/- 0.04 NIHU/cm2 (p < 0.01) for rHir-coated and albumin-coated grafts, respectively. Estimates of the total amount of thrombin inactivated during the perfusion period similarly demonstrated a marked difference between the rHir-coated and control graft segments (125 +/- 8 vs. 3 +/- 14 NIHU; p < 0.005). CONCLUSIONS: These in vitro flow results illustrate that polyester grafts with covalently bound rHir can provide significant reductions in local thrombin concentration under physiologic flow conditions, and can serve as a foundation with which to understand the performance of these grafts when implanted in vivo under physiologic flow and shear rates.
Authors:
S A Berceli; M D Phaneuf; F W LoGerfo
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of vascular surgery : official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter     Volume:  27     ISSN:  0741-5214     ISO Abbreviation:  J. Vasc. Surg.     Publication Date:  1998 Jun 
Date Detail:
Created Date:  1998-07-24     Completed Date:  1998-07-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8407742     Medline TA:  J Vasc Surg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1117-27     Citation Subset:  IM    
Affiliation:
Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass, USA.
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MeSH Terms
Descriptor/Qualifier:
Biocompatible Materials*
Biological Availability
Blood Vessel Prosthesis*
Drug Interactions
Drug Stability
Hemodynamics
Hirudins / pharmacokinetics*
Humans
Perfusion / instrumentation,  methods
Polyesters*
Recombinant Proteins / pharmacokinetics
Surface Properties
Thrombin / pharmacokinetics*
Grant Support
ID/Acronym/Agency:
R01-HL21796-16/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Biocompatible Materials; 0/Hirudins; 0/Polyesters; 0/Recombinant Proteins; EC 3.4.21.5/Thrombin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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