Extracorporeal medical machines such as the pump oxygenator and artificial kidney rely on systemic heparinization to improve blood compatibility. However, heparin can lead to serious complications such as bleeding. The applicants propose a new method to control heparin levels using a blood filter containing immobilized heparinase. Such a filter might be used in situations where it is desired to heparinize the extracorporeal circuit without simultaneous heparinization of the patient. Alternatively, it could eliminate the use of neutralizing compounds such as protamine. Their research has focused not only on the development and testing of the filter, but on heparinase production and purification as well.
The specific aims of the current proposal are: (1) to employ genetic engineering to produce high levels of heparinase, (2) to improve reactor design, (3) to develop comprehensive in vivo models to predict reactor performance, and (4) to conduct in vivo studies using hemodialysis and cardiovascular models in animals, to assess the safety and efficacy of the proposed approach.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM025810-15
Application #
3273314
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Project Start
1979-01-01
Project End
1995-01-31
Budget Start
1993-02-01
Budget End
1994-01-31
Support Year
15
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Type
Schools of Engineering
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02139
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Ameer, G A; Harmon, W; Sasisekharan, R et al. (1999) Investigation of a whole blood fluidized bed Taylor-Couette flow device for enzymatic heparin neutralization. Biotechnol Bioeng 62:602-8
Ameer, G A; Raghavan, S; Sasisekharan, R et al. (1999) Regional heparinization via simultaneous separation and reaction in a novel Taylor-Couette flow device. Biotechnol Bioeng 63:618-24
Sasisekharan, R; Venkataraman, G; Godavarti, R et al. (1996) Heparinase I from Flavobacterium heparinum. Mapping and characterization of the heparin binding domain. J Biol Chem 271:3124-31
Godavarti, R; Cooney, C L; Langer, R et al. (1996) Heparinase I from Flavobacterium heparinum. Identification of a critical histidine residue essential for catalysis as probed by chemical modification and site-directed mutagenesis. Biochemistry 35:6846-52
Ernst, S; Venkataraman, G; Winkler, S et al. (1996) Expression in Escherichia coli, purification and characterization of heparinase I from Flavobacterium heparinum. Biochem J 315 ( Pt 2):589-97
Venkataraman, G; Sasisekharan, V; Herr, A B et al. (1996) Preferential self-association of basic fibroblast growth factor is stabilized by heparin during receptor dimerization and activation. Proc Natl Acad Sci U S A 93:845-50
Ernst, S; Langer, R; Cooney, C L et al. (1995) Enzymatic degradation of glycosaminoglycans. Crit Rev Biochem Mol Biol 30:387-444
Shefer, S D; Breslau, J; Langer, R (1995) Computer simulation of low-density lipoprotein removal in the presence of a bioreactor containing phospholipase A2. Biotechnol Prog 11:133-9
Sasisekharan, R; Leckband, D; Godavarti, R et al. (1995) Heparinase I from Flavobacterium heparinum: the role of the cysteine residue in catalysis as probed by chemical modification and site-directed mutagenesis. Biochemistry 34:14441-8

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