Correlation in the human aorta of apo B fractions with tissue cholesterol and collagen content

Henry F. Hoff, Michael Karagas, Carol L. Heideman, John W. Gaubatz, Antonio Gotto

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

The amounts of buffer- and Triton-extracted apo B (LDL-protein), as well as the sum of these two fractions, were correlated with the total tissue cholesterol and hydroxyproline content (as a measure of collagen) in grossly normal intima, fatty streaks, and fibrous plaques of human aortas obtained at autopsy. Quantitative values of buffer- and Triton-extracted apo B were obtained by sequentially extracting homogenates of aortic intima with an aqueous buffer and one containing Triton X-100, and measuring the apo B content in each extract by an electroimmunoassay relative to plasma LDL or Triton-treated LDL. Significant positive correlations were obtained between the following: tissue cholesterol and both buffer-extracted and total-extracted apo B in grossly normal intima; tissue cholesterol and Triton-extracted apo B in microdissected fibrotic caps and cores of fibrous plaques, as well as in whole plaques. A positive correlation was also obtained between tissue cholesterol and total-extracted apo B in the necrotic core. A significant negative correlation was found between Triton-extracted apo B and collagen in whole plaques. The calculated mean percent of total tissue cholesterol in the different aortic regions that could be present as part of an intact LDL particle were: 100% in grossly normal intima, 16% in fatty streaks, and 11% in fibrous plaques. The positive correlation between Triton-extracted apo B and cholesterol in plaques suggests one or both of the following: the extracellular pool of cholesterol or some material increasing concurrently with cholesterol interacts with apo B or another part of the LDL particle; or the apo B containing lipoprotein is traped in the hydrophobic environment of extracellular lipid. Both possibilities would render the particle less soluble in aqueous buffers. The negative correlation between Triton-extracted apo B and tissue collagen and the lack of a significant correlation between buffer-extracted apo B and collagen content suggests that collagen is probably not responsible for apo B retention in the aortic intima.

Original languageEnglish (US)
Pages (from-to)259-268
Number of pages10
JournalAtherosclerosis
Volume32
Issue number3
DOIs
StatePublished - Jan 1 1979

Keywords

  • Apolipoprotein B (apoB) quantitation
  • Atherosclerosis
  • Chlesterol
  • Collagen
  • Human aorta
  • Intima
  • Low density liproprotein (LDL)

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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