Degradation of the internal elastic laminae in vein grafts of rats with aortocaval fistulae: Potential impact on graft vasculopathy

Chi Jen Chang, Chih Chun Chen, Lung An Hsu, Gow Jyh Chang, Yu Hsein Ko, Chin Fen Chen, Min Yi Chen, Su Hui Yang, Jong Hwei S. Pang

Research output: Contribution to journalJournal Article peer-review

27 Scopus citations

Abstract

The internal elastic lamina (IEL) of vein grafts may be modified when exposed to arterialized hemodynamics. We investigated changes of the IEL in the inferior vena cava (IVC) of rats with aortocaval fistulae (ACF). In the IVC of ACF rats, both a markedly increased flow velocity and a mildly increased pressure were demonstrated. In the lower segment where hemodynamic changes were prominent, neointimal hyperplasia was prominently found. The IEL of the IVC in sham-operated rats, observed by confocal microscopy, was composed of parallel elastic fibers. In ACF rats, the IEL degenerated progressively after surgery. The elastic fibers were stretched and gradually became sparse, a change that was more prominent in the lower segment. Eight weeks after surgery, the IEL hardly existed in some areas of the lower segment. Electron microscopy revealed decreased densities and diameters of elastic fibers. Reverse transcriptasepolymerase chain reaction analysis revealed an upregulation of potent elastases, cathepsins K and S, and matrix metalloproteinase-2 in the IVC of ACF rats. Results of immunohistochemical studies localized cathepsin expression predominantly to the luminal endothelium lining the IEL, suggesting involvement of elastinolysis in the degradation of the IEL. We demonstrated the degradation of the IEL in the vein graft of ACF rats , especially in the segment exposed to prominent hemodynamic changes. IEL degradation may contribute to the development of neointimal hyperplasia in vein grafts.

Original languageEnglish
Pages (from-to)1837-1846
Number of pages10
JournalAmerican Journal of Pathology
Volume174
Issue number5
DOIs
StatePublished - 05 2009

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