Collagen thermal denaturation study for thermal angioplasty based on modified kinetic model: Relation between the artery mechanical properties and collagen denaturation rate

N. Shimazaki, T. Hayashi, M. Kunio, T. Arai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have been developing the novel short-term heating angioplasty in which sufficient artery lumen-dilatation was attained with thermal softening of collagen fiber in artery wall. In the present study, we investigated on the relation between the mechanical properties of heated artery and thermal denaturation fractures of arterial collagen in ex vivo. We employed Lumry-Eyring model to estimate temperature- and time-dependent thermal denaturation fractures of arterial collagen fiber during heating. We made a kinetic model of arterial collagen thermal denaturation by adjustment of K and k in this model, those were the equilibrium constant of reversible denaturation and the rate constant of irreversible denaturation. Meanwhile we demonstrated that the change of reduced scattering coefficient of whole artery wall during heating reflected the reversible denaturation of the collagen in artery wall. Based on this phenomenon, the K was determined experimentally by backscattered light intensity measurement (at 633nm) of extracted porcine carotid artery during temperature elevation and descending (25°C→80°C→25°C). We employed the value of according to our earlier report in which the time-and temperature- dependent irreversible denaturation amount of the artery collagen fiber that was assessed by the artery birefringence. Then, the time- and temperature- dependent reversible (irreversible) denaturation fraction defined as the reversible ((irreversible) denatured collagen amount) / (total collagen amount) was calculated by the model. Thermo-mechanical analysis of artery wall was performed to compare the arterial mechanical behaviors (softening, shrinkage) during heating with the calculated denaturation fraction with the model. In any artery temperature condition in 70-80°, the irreversible denaturation fraction at which the artery thermal shrinkage started was estimated to be around 20%. On the other hand, the calculated irreversible denaturation fraction remained below 5% and reversible denaturation fraction reached up to 20% while the artery softening occurred without shrinkage. We think that our model of arterial collagen thermal denaturation might be reasonable to estimate the artery mechanical properties during heating.

Original languageEnglish
Title of host publicationOptical Interactions with Tissues and Cells XXI
DOIs
Publication statusPublished - 2010 May 6
EventOptical Interactions with Tissues and Cells XXI - San Francisco, CA, United States
Duration: 2010 Jan 252010 Jan 27

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7562
ISSN (Print)1605-7422

Other

OtherOptical Interactions with Tissues and Cells XXI
CountryUnited States
CitySan Francisco, CA
Period10/1/2510/1/27

Keywords

  • Artery wall
  • Balloon angioplasty
  • Collagen
  • Thermal denature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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