Heparinized polyvinyl alcohol to specifically adsorb low-density lipoprotein from plasma.

INTRODUCTION: A medical adsorbent for blood purification was developed to specifically adsorb low-density lipoprotein (LDL) from hypercholesterolemia patient's plasma by covalently immobilizing heparin onto the surface of polyvinyl alcohol (PVA) with the couplant toluence-2,4-diisocyanate (TDI). METHODS: We used IR to demonstrate the success of covalently immobilizing heparin onto the surface, and investigated its adsorption of LDL, and primarily evaluated its hemo-compatibility using tests for platelet adhesion, the degree of platelet activation and a hemolysis test. RESULTS: (1) Heparin was successfully covalently immobilized onto the surface, the maximum amount of heparin immobilized on the surface of 1g PVA-1799 granules was about 5 µg; (2) one optimal condition for adsorption of LDL from hyperlipidemia plasma was a pH within the range of 7.2∼9.5, accordingly the adsorptive ratio (adsorbent/g: plasma/L=1:2) for LDL was about 70%; (3) it exhibited good hemo-compatibility. CONCLUSION: The adsorbent results in satisfactory adsorption of LDL with good hemo-compatibility; it could potentially be used as a blood purification material, and immobilization of heparin onto medical materials may be a way to develop an LDL-specific adsorbent for blood purification.

Synergistic effects of polymer adsorbents on the performance of bilirubin hemoperfusion.

Neonatal hyperbilirubinemia (jaundice) is a common disease with high incidence. Currently, the clinical inefficiency of adult bilirubin hemoperfusion medical adsorbent is a major technical barrier for the application of hemoperfusion treatment to rescue the severe neonatal jaundice. Based on the well-known principle of synergistic effects, a series of customized bilirubin polymeric compounds, comprised of one or more of the following components (glycidyl methacrylate, sodium acrylate, methacrylic acid isooctyl, hexamethylene diamine, albumin), were designed and fabricated based on molecular design. Their adsorption performances upon bilirubin were investigated and compared under the same conditions, and the compound with the highest adsorption performance was then subject to preliliminary safety assessments and compared with a commercial one (BS330). The results showed that positive synergistic effects appeared on the adsorption performance to adsorb bilirubin based on this study, and the one comprised of glycidyl methacrylate+sodium acrylate+methacrylic acid isoocty+hexamethylene diamine+albumin possesses the highest adsorption performance as well as outome clinical acceptable medical safety assessments, and its adsorption efficiency was up to 46% while the commerical one's was about 26% under the same conditions. This study sheds a new light on how to design and develop hemoperfusion bilirubin adsorbents with good overall clinical performance, as well as providing a novel idea and experimental referrences for future related topics.

Preparation of heparin-immobilized PVA and its adsorption for low-density lipoprotein from hyperlipemia plasma.

In this study, heparin was covalently coupled by glutaraldehyde to Poly(vinyl alcohol) [PVA] in solid-liquid two-phase reaction system by two-step synthesis method to prepare a LDL-selective adsorbent. The parameters (the material ratio, reaction time and dosage of catalyzer) were investigated to evaluate their effect upon the immobilized amount of heparin onto the surface of PVA, IR was used to verify the covalent immobilization result and the heparin-modified PVA was also undergone the evaluation of its adsorption capability for low-density lipoprotein from hyperlipemia plasma, and its hemocompatibility was preliminarily evaluated by platelet adhesion test. Results showed: (1) under optimized reaction conditions the highest immobilization amount of heparin onto PVA surface within the experiments of this study has been obtained; (2) the optimized reaction conditions were: (i) at the refluxing temperature 78 degrees C; (ii) the material ratio of "PVA(g): 50% glutaraldehyde (ml)" was about "1:3"; (iii) the reaction time was about 5 h; and (iv) the amount of catalyzer (concentrated HCL) was about 1% of the 50% glutaraldehyde; (3) within the experiments of this study the highest immobilization amount would be up to 25 microg heparin on the surface of per g PVA granules; (4) the heparin-modified PVA granules showed significant adsorption for LDL under faintly alkaline environment (pH=7.2-9.5) ; (5) The result of platelet adhesion test showed no platelet adhered to its surface. Therefore, immobilization of heparin onto the surface of a support is one approach to prepare a kind of LDL adsorbent for blood purification.