Transient diffusion of albumin in aortic walls: Effects of binding to medial elastin layers

Anita R. Goriely, Ann L. Baldwin, Timothy W. Secomb

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The goal of this study was to measure diffusive transport of albumin through artery walls experimentally and to analyze the results theoretically, taking into account the binding of albumin to elastic lamellae. Segments of rabbit aorta were placed in solutions of fluorescently labeled albumin for periods of 30, 60, 90, and 120 min, and the distributions of fluorescence intensity through the arterial media were observed. On average, intensity increased almost linearly with time. Bands of high intensity were observed corresponding to elastin layers within the media. The temporal and spatial variations of intensity were compared with predictions of theoretical models, including effects of albumin binding and hindered diffusion resulting from the complex wall structure. Based on these analyses, it was concluded that the spatial distribution of free albumin within the media equilibrated relatively rapidly, and that the observed linear increase in intensity reflected gradual accumulation of albumin bound to medial elastin layers. The results imply that previous theoretical analyses, in which binding was neglected, substantially underestimated albumin diffusivity in the aortic wall. With respect to stent-associated delivery of inhibitors of vascular cell proliferation, the results suggest that albumin might serve as an "affinity vehicle" for drug delivery to the aorta, by attaching the drug to an abundant component of the artery wall.

Original languageEnglish (US)
Pages (from-to)H2195-H2201
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume292
Issue number5
DOIs
StatePublished - May 2007

Keywords

  • Arteries
  • Drug delivery
  • Elastic lamellae
  • Rabbit

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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