Atherosclerosis In Dogs Research Articles

INTERRELATION OF AORTIC AND CORONARY ARTERIAL HYPERTENSION WITH DIETARY-INDUCED HYPERCHOLESTEREMIA ON ATHEROSCLEROSIS IN DOGS

Journal Article Interrelation of Aortic and Coronary Arterial Hypertension with Dietary-Induced Hypercholesteremia on Atherosclerosis in Dogs Get access Nutrition Reviews, Volume 19, Issue 6, June 1961, Pages 179–182, https://doi.org/10.1111/j.1753-4887.1961.tb01959.x Published: 01 June 1961

EXPERIMENTAL ATHEROSCLEROSIS IN DOGS WITH AORTIC GRAFTS

Experimental Atherosclerosis in Dogs with Aortic Grafts Get access Nutrition Reviews, Volume 19, Issue 11, November 1961, Pages 338–340, https://doi.org/10.1111/j.1753-4887.1961.tb01863.x Published: 01 November 1961

Association between diabetes mellitus, hypothyroidism or hyperadrenocorticism, and atherosclerosis in dogs.

The objective of this study was to determine whether dogs with atherosclerosis are more likely to have concurrent diabetes mellitus, hypothyroidism, or hyperadrenocorticism than dogs that do not have atherosclerosis. A retrospective mortality prevalence case-control study was performed. The study group included 30 dogs with histopathological evidence of atherosclerosis. The control group included 142 dogs with results of a complete postmortem examination, a final postmortem examination diagnosis of neoplasia, and no histopathological evidence of atherosclerosis. Control dogs were frequency matched for age and year in which the postmortem examination was performed. Proportionate changes in the prevalence of diabetes mellitus, hypothyroidism, and hyperadrenocorticism were calculated by exact prevalence odds ratios (POR), 95% confidence intervals (95% CI), and P values. Multiple logistic regression analysis was used to examine the combined effects of prevalence determinants while controlling for age and year of postmortem examination. Dogs with atherosclerosis were over 53 times more likely to have concurrent diabetes mellitus than dogs without atherosclerosis (POR = 53.6; 95% CI, 4.6-627.5; P = .002) and over 51 times more likely to have concurrent hypothyroidism than dogs without atherosclerosis (POR = 51.1; 95% CI, 14.5-180.1; P < .001). Dogs with atherosclerosis were not found to be more likely to have concurrent hyperadrenocorticism than dogs that did not have atherosclerosis (POR = 1.8; 95% CI, 0.2-17.6; P = .59). Diabetes mellitus and hypothyroidism, but not hyperadrenocorticism, are more prevalent in dogs with atherosclerosis compared to dogs without atherosclerosis on postmortem examination.

Association between Diabetes Mellitus, Hypothyroidism or Hyperadrenocorticism, and Atherosclerosis in Dogs

Association between Diabetes Mellitus, Hypothyroidism or Hyperadrenocorticism, and Atherosclerosis in Dogs

Systemic atherosclerosis in dogs: histopathological and immunohistochemical studies of atherosclerotic lesions.

Histopathological and immunohistochemical studies were carried out on five cases of canine systemic atherosclerosis. The five animals were male, and showed hypercholesterolaemia and hypertriglyceridaemia on biochemical analysis of plasma. Histopathologically, atherosclerotic lesions were seen in the aorta and muscular arteries in many organs, including the heart, spleen, kidneys, lungs, pancreas, alimentary tract, urogenital organs, eyes, prostate and urinary bladder. The lesions were characterized by the deposition of lipids and infiltration of lipid-laden foamy cells in the tunica intima and tunica media, sometimes forming fibrofatty plaques, containing abundant sudanophilic material, cholesterol clefts and mineralized material. The lesions started in the tunica intima and extended to the tunica media and tunica adventitia. Immunohistochemical examination with canine apolipoprotein B-100 (CApoB-100) antibody identified the lipids containing low density lipoprotein. Immunoreactivity to CApoB-100 antibody was recognized in the tunica intima, lipid-laden foamy cell cytoplasm and smooth muscle cells in the tunica media, and fibrofatty plaque. These histopathological and immunohistochemical features were similar to those of human atherosclerotic lesions.

Failure of regression of atherosclerosis in dogs with moderate cholesterolemia

Controversy exists as to whether regression occurs in atherosclerotic plaques in response to serum cholesterol reduction. In the present study, using sequential observation of canine atherosclerosis, we attempted regression in hypothyroid dogs. Animals with established lesions prior to a regression attempt were placed on a 0.05% cholesterol diet and observed up to 60 months. Weighted average cholesterols ranged from 235 to 587 mg/100 ml during the regression attempt. A control fed for the entire period of the experiment, 75 months, had an average weighted cholesterol of 435 mg/100 ml. We failed to obtain regression of atherosclerotic plaques in spite of reduction of serum cholesterol from high to moderate levels. The lesions in the experimental animals contained less lipid and more collagen and calcium than occurred in the control. Complicated plaques with aneurysm formation, stenosis of the distal aorta, and gangrene of the tail were also noted.

Thrombosis in association with atherosclerosis induced by dietary perturbations in dogs.

The distribution, severity, and complications of diet-induced atherosclerosis in dogs can be altered by changing the source of fat in the diet. Thrombosis and thromboembolic disease associated with atherosclerosis occurred with diets containing beef tallow and lard of coconut oil but were absent in dogs fed cottonseed oil as a source of fat. Experiemtnal animals with and without thrombosis are of value as models in elucidating the role of platelets and thrombostatic mechanisms in atherosclerosis.

Effect of functional strain of the CNS and endocrine disturbances on development of experimental atherosclerosis in dogs

Functional strain on the CNS was combined in chronic experiments on seven dogs with other factors changing the hormonal status of the animal-castration and injection of mercazolyl in doses of 1.5–2.5 mg/kg (group 1). The six control dogs (group 2) underwent castration and injection of mercazolyl only. The animals of group 1 developed persistent hypercholesteremia, atherosclerotic changes in various intramural arteries, especially of the myocardium, and also degenerative changes in the parenchyma of certain organs, which were not found in the animals of group 2. The results of this investigation demonstrate the important role of functional strain on the CNS as a leading “risk” factor responsible for disturbances of the regulation of lipid metabolism and the development of atherosclerotic changes in the vessels.

The influence of myocardial bridges on the wall of the coronary arteries during cholesterol-induced atherosclerosis in dogs

In dogs, the influence of myocardial bridges of the coronary arteries on the development of coronary atherosclerosis was investigated under experimental conditions of early (6 months) and advanced (13 months) atherosclerosis. The adverse effect of myocardial bridges was shown in cholesterol-induced coronary atherosclerosis in dogs. In both early and advanced phases of coronary atherosclerosis the bridges caused unequal development of the sclerotic changes in the arterial wall which were most apparent in the subepicardial segments. In the early phases the atherosclerotic lesions occur mostly in the intima, in the advanced degree of atherosclerosis they occur throughout the arterial wall. In the subepicardial arterial portions of the anterior descending branch, mainly proximal to the bridge, the intima becomes thickened with advancing atherosclerosis; in the small branches ramifying before the bridge, this even leads to complete occlusion. In contrast, in the intra-myocardial portion below the bridge, the intima is thinnest. Evaluation of the estimated differences in area (evoked by the atherosclerosis) between the individual layers of the arterial wall in the subepicardial and those in intramyocardial segments, shows a statistically significant relation between the presence of myocardial bridges and certain structural changes in the arterial wall.

Effects of distal intestinal bypass and other gastrointestinal operations on experimental hypercholesterolemia and atherosclerosis

Further appraisal has been made of the effects of distal intestinal bypass in experimental hypercholesterolemia and atherosclerosis in dogs. In this study, bypass of 30 to 40 per cent of distal small intestine successfully prevented the development of hypercholesterolemia and atherosclerosis in animals on a vigorous atherogenic regimen; the test regimen included an experimental model which had been previously shown to enhance segmental deposition of atheroma. Bypass of 15 per cent of small intestine was not satisfactory in this regard, although both 15 per cent bypass and 15 per cent resection afforded a limited degree of protection against induced hypercholesterolemia and atherosclerosis. Very little difference was observed between the excellent protective effects of 30 per cent intestinal resection and 30 per cent intestinal bypass in these preliminary experiments. Comparison of the effects of truncal vagotomy and selective gastric vagotomy in animals on atherogenic regimen suggests that truncal vagotomy offers a modest protective effect against hypercholesterolemia and experimental atherosclerosis whereas selective gastric vagotomy offers no protection whatsoever. Further evaluation of the preventive effects of 30 to 40 per cent intestinal bypass and the other gastrointestinal operations in experimental atherosclerosis is clearly indicated and an assessment of their therapeutic value in established experimental atherosclerosis must be made.

Suppression of experimental atherosclerosis in dogs by dietary linoleic acid.

SummarySevere atherosclerotic lesions were induced in 4 months in dogs fed a diet restricted in linoleic acid content and supplemented with cholesterol and thiouracil. Only one minor lesion was found in a group of dogs fed a similar diet supplemented with cholesterol and thiouracil which was isocaloric in fat but contained a high concentration of linoleic acid. In the low linoleic acid group, serum total cholesterol increased to high levels within 2 months and remained constant for the remainder of the feeding period. In the high linoleic acid group, serum total cholesterol levels increased more slowly reaching levels compatible with the group fed low linoleic acid diets at the end of 4 months. Less than 25% of the serum esterified cholesterol was bound to linoleic and arachidonic acids in dogs fed diets low in linoleic acid, whereas this value was 75% in dogs fed high linoleic acid diets. It is concluded that dietary linoleic acid retards lesions in dogs by promoting cholesterol excretion.

Reactivity of arteries in the early stage of development of experimental cholesterol atherosclerosis in dogs

In experimental atherosclerosis in dogs vascular reactivity becomes changed at the early stage of the process, prior to the development of specific morphological changes.

The rapid development of arterial lesions in dogs fed an “infarct-producing” diet

A dietary method for the rapid production of atherosclerosis in dogs has been presented. Previous methods involving feeding of cholesterol, bile salts and thiouracil have usually required more than one year to produce atherosclerosis. The method presented herein consists essentially of adding large amounts of highly saturated fats to the diets previously used. With this method atherosclerotic lesions have been produced in as short a period as 8 weeks.

The involution of experimental cholesterol atherosclerosis in dogs

Over a six-month period following the end of the cholesterol and 6-methylthiouracil feeding period, the ballistocardiographic changes in dogs went back more rapidly and more completely to the initial level than the electrocardiographic changes.

Enhancement of experimental atherosclerosis by ACTH in the dog.

SummaryOne to 3 injections of 40 units of ACTH-gel significantly enhanced the elevated serum cholesterol and phospholipid levels produced by subsequent thiouracil and cholesterol feeding in the dog. This effect was associated with paralytic strokes in 4 of 10 dogs. Autopsy revealed markedly more widespread and more severe atherosclerosis in dogs pretreated with ACTH than in dogs who received only a high thiouracil and cholesterol diet.The authors are indebted to Drs. Wilfrid Dixon and Frederick Moore for statistical evaluation of the data and Drs. John Mehl and Ross Jacobs for supervision of lipid and lipoprotein determinations.

The Accelerating Effect of Muscular Exercise on Experimental Atherosclerosis

Many articles have appeared recently in the lay press extolling the virtues of muscular exercise. Further, experiments in our laboratory have indicated that after occlusion of a major blood vessel, regular, progressive muscular exercise seems to speed the development of collateral circulation. Clinically, our experience is similar, for patients with claudication from segmental arterial occlusion may increase their walking tolerance by progressive daily exercise. Thus, since there are forces existing which tend toward increasing muscular activity in persons who may be atherosclerosis-prone, it has become important to know whether exercise may retard or augment atherosclerosis. We have tried to secure information on this point, using cholesterol-thiouracil-induced atherosclerosis in dogs and recognizing full well the objections to such preparations. <h3>Methods</h3> Ten mongrel dogs of similar size and weight were placed on a diet of 70% horsemeat, 25% feed grain, 5% cholesterol, and 150 mg. of thiouracil daily. One pound of this

Effect of experimental renal hypertension on experimental thiouracil-cholesterol atherosclerosis in dogs.

Experimental renal hypertension accelerated the onset and accentuated the severity of thiouracil-cholesterol atherosclerosis in dogs. Increased blood pressure and other hemodynamic changes appear to be responsible for these effects. Hypertension and sex were without significant effect on serum cholesterol, cholesterol: phospholipid ratio and low density lipoproteins. Sex had no significant effect on the incidence or severity of this experimental atherosclerosis, including coronary involvement.

Protein-lipid relationships in experimental canine atherosclerosis.

The applicability of Cohn's method number 10 to the study of dog plasma has made possible this investigation of experimental canine atherosclerosis. Administration of thiouracil which causes hypercholesterolemia but no atherosclerosis in dogs produces no considerable alteration in the distribution of plasma lipoproteins. High cholesterol feeding and administration of thiouracil causes both atherosclerosis and significant alterations in the distribution of lipoproteins.

Development of atherosclerosis in dogs with hypercholesterolemia and chronic hypertension.

Hypercholesterolemia was induced in pure-bred dogs by cholesterol feeding and propylthiouracil or radioiodine. Hypertension induced by the injection of silica into the renal artery increased the severity of aortic atherosclerosis. Marked hypercholesterolemia increased the severity of aortic atherosclerosis even in normotensive dogs.

Cholesterol metabolism and arteriosclerosis

Cholesterol metabolism and arteriosclerosis