The sympathetic nervous system and atherosclerosis

Abstract

Morphometric and chemical changes in the arterial wall were studied after 12 months of diet-induced atherosclerosis in rhesus monkeys treated with either bilateral surgical thoracic sympathectomy or propranolol. There was a marked reduction in the progression of atherosclerosis in the carotid arteries and a moderate reduction in the disease found in the thoracic aorta of monkeys treated initially with a sympathectomy, in comparison to control monkeys fed an atherogenic diet alone. Propranolol at a dose of 40 mg/12 hrs also seemed to reduce the progression of atherosclerosis in the carotid arteries and thoracic aorta, although the differences were less dramatic. There were minimal differences in the extent of atherosclerosis in the abdominal aorta or femoral arteries of animals in either treatment group as compared with the control group. Similarly, the chemical composition of these same major vessels showed no significant differences. Therefore, in the face of severe atherogenic stimuli, chemical or surgical sympathectomy may be useful in controlling atherosclerosis in specific arterial beds.

Arterial Stiffening Influence of Sympathetic Nerve Activity

“…It may also be produced, on a more chronic basis, by growth of less distensible connective tissue for which sympathetic influences are a trophic factor. 11,12 The participation of the sympathetic nervous system in the alterations of arterial distensibility in a post-transplantation organ does not exclude the involvement of other factors, given the complex alterations in the local milieu brought about by organ transplantation, although our data allow us to exclude or consider unlikely a number of them. After 40 days, the transplanted hand still showed some edema, which subsided entirely over the subsequent follow-up period.…”

Sympathectomy Causes Aggravated Lesions and Dedifferentiation in Large Rabbit Atherosclerotic Arteries without Involving Nitric Oxide

“…Fronek and Turner [29] and Fronek[ 49] found evidence of greater atherosclerosis in the absence of or with reduced sympathetic innervation. However, a study in monkeys [50] fed a hypercholesterolemic diet found that 12 months after surgical thoracic sympathectomy (with reduced blood pressure, BP) there were fewer plaques in the aorta or the carotid artery, but that the coronary artery showed the opposite trend. This suggests that the size and/or the nature of the artery (elastic or muscular) may be of importance in determining the ultimate influence of the sympathetic nerves.…”

Obesity Paradox in Hypertension

“…In diverse contexts, both experimental and clinical, persistent sympathetic nervous system activations have been causally linked to cardiovascular damage, to endothelial dysfunction, 46 to the development of left ventricular hypertrophy, 47 to atherosclerosis development 48 and to atrial and ventricular arrhythmias. 19,49,50 Single Sympathetic Nerve Firing Salvos Direct recording from the human cardiac sympathetic nerves is not possible, but the presence there of multiple firing salvos is probable, as patients who have nerve firing salvos recorded at microneurography have, in parallel, the highest levels of cardiac norepinephrine spillover.…”

“…There exist several classical studies of this type, including that of Lichtor et al 48 in rhesus monkeys fed an atherogenic diet, in which surgical thoracic sympathectomy prevented atherosclerosis development in the carotid arteries and thoracic aorta.…”

“…• Endothelial damage (88)(89)(90)(91) • Atherogenesis (48,(94)(95)(96) • Left ventricular hypertrophy (46,97) • Atrial and ventricular cardiac arrhythmias (48,54) • Thrombogenesis in myocardial infarction and stroke (99) Excess Clinical Cardiovascular Endpoints (5,14)…”