Atherosclerotic Segments Research Articles

Vaporization of atherosclerotic plaques by spark erosion

An alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and documented histologically in vitro from 30 atherosclerotic segments of six human aortic autopsy specimens. Craters with a constant area and a depth that varied according to the duration of application were produced. The method was confirmed to be electrically safe during preliminary in vivo trials in the coronary arteries of seven anesthetized pigs. The main advantages of this technique are that it is simpler to execute than laser irradiation and potentially more controllable.

Release of atherosclerotic debris after transluminal angioplasty.

To determine if there is release of endothelial cells or plaque contents after percutaneous transluminal angioplasty, effluent from atherosclerotic segments of the aorta and iliac arteries of rabbits were collected before and after angioplasty. No endothelial cells or cholesterol plates were identified in the preangioplasty effluents. Only a few single endothelial cells and cholesterol crystals were found in effluents after angioplasty. We conclude that embolization of endothelial fragments and cholesterol plates occurs during angioplasty, but only to a minor degree, and is probably not clinically important.

Enhanced synthesis and accumulation of collagen in cholesterol-aggravated pigeon atherosclerosis

Atherosclerotic segments of pigeon aorta synthesized collagen at four times the rate found in normal aorta (Athero = 2071 ± 1339 ng/g/h; Control = 497 ± 192 ng/g/h; P < 0.025). Similar results were obtained when synthesis was expressed per mg DNA. Elevation in collagen synthesis was relatively specific, collagen accounting for 4% of total protein synthesis in lesion-free aorta and 11.5% in atherosclerotic aorta. Substantial increases in total collagen were observed in atherosclerotic aortas (Athero = 9.9 ± 3.1 mg/aorta; Control = 6.0 ± 1.3 mg/aorta; P < 0.05). Ultrastructural studies revealed the accumulation of large amounts of dense fibrillar collagen in the sub-endothelial region of the plaque. Plaque cells contained multiple vacuoles, an extensive rough endoplasmic reticulum and many mitochondria, suggesting active protein synthesis. It is concluded that increased collagen biosynthesis and deposition is an important metabolic derangement in lipid-rich atherosclerotic lesions which promotes their gradual conversion to fibrous plaques.

Uptake and esterification of exogenous cholesterol by organ cultures of normal and atherosclerotic pigeon aorta.

SummaryAn organ culture system is described in which segments of pigeon aorta have been maintained in a metabolically active state for up to 9 days. Using this system, we have studied the uptake and metabolism of cholesterol-1,2-3H and oleic acid-1-14C by normal and atherosclerotic arterial tissue.The uptake of cholesterol-1,2-3H by arterial tissue was rapid and was similar in both boiled and viable arterial segments. Results suggest a physical chemical mechanism for uptake of free cholesterol. Arterial segments esterified oleic acid-1-14C to phospholipid, triglyceride, and cholesteryl ester. Cholesterol-1,2-3H was also esterified with a significantly increased rate of esterification seen in arterial segments from atherosclerotic aortas. Uptake of free cholesterol was not significantly different in normal and atherosclerotic arterial segments.