Aneurysm or occlusive disease - Factors determining the clinical course of atherosclerosis of the infrarenal aorta

G. S. McGee, B. T. Baxter, V. P. Shively, R. Chisholm, W. J. McCarthy, W. R. Flinn, J. S.T. Yao, W. H. Pearce

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Abstract

Atherosclerosis of the infrarenal aorta results in distinct clinical entities-aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA). Although loss of collagen has been implicated in AAA, collagen accumulation plays a role in AOD. In vivo collagen-gene expression can be assessed using complementary DNA for collagen types I and III α-chains. The purpose of this study is to compare total collagen (type I + III) and collagen types I and III messenger RNA in AAA, AOD and normal aorta. Specimens were collected from the infrarenal aorta during operation for AOD (n = 7), AAA (n = 7), autopsy, or organ procurement (normal; n = 7). Northern transfer analysis of total RNA was used to compare mRNA levels for type I and III collagen. After preliminary extraction, specimens were hydrolyzed for hydroxyproline analysis used to calculate total collagen (type I + III). Relative levels of type I (pro-a1 [1]) mRNA were greater in both AOD (0.77 ± 0.35) and AAA tissue (0.94 ± 0.24; p = 0.6) than in normal aorta (0.02 ± 0.03). Type III (pro-a1 [III]) mRNA levels were also greater in AOD (2.52 ± 0.19; p = 0.09) and AAA tissue (3.15 ± 1.3) than in normals (0.97 ± 0.47). Total collagen concentration was increased in AOD (45.6% ± 3.1% dry weight; p < 0.05) but not AAA tissue (27.8% ± 4%) when compared to normal aorta (34.7% ± 2.3%). Collagen type I and III gene expression is greater in older, diseased aorta, yet collagen accumulated only in AOD. This implies a similar synthetic response in both AOD and AAA. Thus, proteolytic degradation in AAA appears to determine collagen content and possibly the clinical course of the atherosclerotic process.

Original languageEnglish (US)
Pages (from-to)370-376
Number of pages7
JournalSurgery
Volume110
Issue number2
StatePublished - Dec 1 1991

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ASJC Scopus subject areas

  • Surgery

Cite this

McGee, G. S., Baxter, B. T., Shively, V. P., Chisholm, R., McCarthy, W. J., Flinn, W. R., Yao, J. S. T., & Pearce, W. H. (1991). Aneurysm or occlusive disease - Factors determining the clinical course of atherosclerosis of the infrarenal aorta. Surgery, 110(2), 370-376.