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Hydrolytic degradation of poly(carbonate)-urethanes by monocyte-derived macrophages

Paper ID Volume ID Publish Year Pages File Format Full-Text
13571 881 2001 9 PDF Available
Title
Hydrolytic degradation of poly(carbonate)-urethanes by monocyte-derived macrophages
Abstract

Polycarbonate (PCN)-based polyurethanes (PCNU) are rapidly becoming the chosen polyurethane (PU) for long-term implantation since they have shown decreased susceptibility to oxidation. However, monocyte-derived macrophages (MDM), the cell implicated in biodegradation, also contain hydrolytic activities. Hence, in this study, an activated human MDM cell system was used to assess the biostability of a PCNU, synthesized with 14C-hexane diisocyanate (HDI) and butanediol (BD), previously shown to be susceptible to hydrolysis by cholesterol esterase (CE). Monocytes, isolated from whole blood and cultured for 14 days on polystyrene (PS) to mature MDM, were gently trypsinized and seeded onto 14C-PCNU. Radiolabel release and esterase activity, as measured with p-nitrophenylbutyrate, increased for almost 2 weeks. At 1 week, the increase in radiolabel release and esterase activity were diminished by more than 50% when the protein synthesis inhibitor, cycloheximide, or the serine esterase/protease inhibitor, phenylmethylsulfonylfluoride was added to the medium. This strongly suggests that in part, it was MDM esterase activity which contributed to the PU degradation. In an effort to simulate the potential combination of oxidative and hydrolytic activities of inflammatory cells, 14C-PCNU was exposed to HOCl and then CE. Interestingly, the release of radiolabeled products by CE was significantly inhibited by the pre-treatment of PCNU with HOCl. The results of this study show that while the co-existing roles of oxidation and hydrolysis in the biodegradation of PCNUs remains to be elucidated, a clear relationship is drawn for PCNU degradation to the hydrolytic degradative activities which increase in MDM during differentiation from monocytes, and during activation in the chronic phase of the inflammatory response.

Keywords
Biodegradation; Polyurethane; Monocyte-derived macrophages; Hydrolytic activities; Oxidation
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Hydrolytic degradation of poly(carbonate)-urethanes by monocyte-derived macrophages
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 22, Issue 22, 15 November 2001, Pages 3025–3033
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us