Robert J. Elliott

Lipid analysis and fatty acid profiles of individual arterial atherosclerotic plaques

A protocol for the analysis of the lipid profile of microsamples of aortic tissue was developed. Lipid extraction was from intact tissue using acetone and chloroform/methanol (2/1, v/v). The extract was analyzed for total lipid, esterified cholesterol, cholesterol, triacylglycerol, and phospholipid. The extract was then processed to separate cholesteryl esters, triacylglycerol, and phospholipid which were hydrolyzed and the fatty acid composition was determined by GLC of pentafluorobenzyl ester derivatives. A lipid profile could be obtained on samples with a wet weight of 5 mg.

Formation of a lipid gradient across the human aortic wall during ageing and the development of atherosclerosis

The smooth muscle cell invasion and macrophage stimulation within the intima during prolonged exposure to high blood levels of cholesterol esters contribute to increased production of connective tissue matrix. The thickened intima in turn immobilising more LDL derived lipid from the plasma. With damage to the internal elastic lamellae, from essential hypertension, the absorbed lipid can move down a concentration gradient into the medial tissue. This model was supported by our laboratory finding of a lipid gradient across the aorta wall. The gradient commenced shortly after completion of body growth, when the transmedial gradient became detectable. The slope of the gradient progressively increased during ageing. Association of the lipid medial gradient with the degree of atherosclerotic involvement suggested that the gradient influenced the development of intimal lesions. Accumulation of lipid within the medial tissue may then reduce the inward lipid transfer rate from the intima, promoting increased intimal retention and cause the formation of atherosclerotic plaques from the fat saturated intima.