Aortic Acid Mucopolysaccharides Research Articles

The Effect of Inhibition of the Sympathetic Nervous System on Aortic Acid Mucopolysaccharides in Spontaneously Hypertensive Rats

The Effect of Inhibition of the Sympathetic Nervous System on Aortic Acid Mucopolysaccharides in Spontaneously Hypertensive Rats

Aortic acid mucopolysaccharides: changes during pregnancy, enovid-treatment, and hypercholesteremia in rabbits.

Thirty-six adult female rabbits were divided into four groups: controls, pregnant, Enovid-treated, and cholesterol-fed. Hypolipidemia was noted in pregnant rabbits and hyperlipidemia in cholesterol-fed rabbits. The nondialyzable aortic uronic contents of pregnant and Enovid-treated rabbits were not different from those of the controls, although previous histochemical studies on the same aortas revealed a marked reduction of alcian blue positive materials in the aortas of both pregnant and Enovid-treated rabbits. This false reduction may be the result of qualitative changes of aortic AMPS during pregnancy; these changes are very different from the quantitative increases found in atherosclerotic aortas. The latter showed no loss of stain with alcian blue dye.

Copper deficiency in chicks: effects of ascorbic acid on iron, copper, cytochrome oxidase activity, and aortic mucopolysaccharides.

1. Copper deficiency was induced in newly hatched chicks by feeding on a milk-based diet for 12 d; effects of supplementation with ascorbic acid were studied.2. Cu deficiency alone resulted in 30% mortality from aortic rupture. This was associated with a 20% increase in total acid mucopolysaccharides in the aorta, manifested as an increase in chondroitin sulphate and a relative decrease in hyaluronic acid. Cytochrome oxidase activity of liver and heart was less than half that of the controls.3. Supplementing the Cu-deficient diet with 0.5 % L-ascorbic acid increased mortality to 40%, raised total aortic acid mucopolysaccharides to a higher level, and increased liver iron by 36%.4. Supplementing the control diet with ascorbic acid decreased liver Cu by 30% and significantly reduced total aortic acid mucopolysaccharides.5. The enhancement of the Cu-deficiency effect by ascorbic acid probably results from interactions between ascorbic acid and absorption or metabolism of Cu; untoward effects of supplementing the control diet with ascorbic acid may be interpreted as manifestations of ascorbic acid toxicityper se.

Comparative studies of aortic acid mucopolysaccharides in fifteen species

1. 1. Aortic acid mucopolysaccharides (AMPS) were studied in fifteen different species including: dusky shark, dog fish, frog, turtle, chicken, pheasant, mouse, rat, guinea pig, hamster, rabbit, cat, dog, cow and rhesus monkey. 2. 2. Phylogenetically close species (e.g. cat and dog, rat and mouse chicken and pheasant) had similar concentration of AMPS in aortic tissue. 3. 3. Thoracic aortic segment had a higher concentration of total AMPS and chondroitin sulfate B than abdominal segment. 4. 4. Chondroitin sulfater B was not observed in aortic tissue of dusky shark and dog fish, the most primitive species subjected to this study.

Relative immunity to arteriosclerosis in rabbits during the hair-shedding period

The extent and severity of arteriosclerosis in rabbit aorta induced by exposure to short periods of systemic hypoxia for two weeks were studied during the hair-shedding period (September through December). Two series of experiments were carried out in relation to two different shedding periods with an interval of 1 year. The entire study involved 152 rabbits. Three experiments were performed in shedding and three in nonshedding periods. While shedding, the rabbits exposed to hypoxia developed slight gross arteriosclerosis in contrast to the severe arteriosclerosis that developed while the animals were not shedding. Qualitatively, the gross and microscopic changes did not differ during and outside the shedding periods. Comparison of the biochemical changes in the aortic acid mucopolysaccharides and collagen induced by the systemic hypoxia during the shedding and nonshedding periods showed no statistically significant differences. The resistance to arteriosclerosis during shedding may be due to hormonal factors, which also may be of importance to the development of arteriosclerosis in other species. Furthermore, the phenomenon has to be taken into consideration in experimental studies of rabbit arteriosclerosis.

CORTICOSTEROIDS AND VASCULAR CONNECTIVE TISSUE.

ABSTRACT Male albino rabbits were injected daily with noradrenaline plus prednisone and noradrenaline plus saline for two weeks. Prednisone enhanced the development of the gross and microscopic arteriosclerotic lesions of the aorta induced by noradrenaline, but inhibited the synthesis and the accumulation of acid mucopolysaccharides elicited by the noradrenalineinduced damage of the aortic wall. The effect of prednisone on the aortic acid mucopolysaccharides reflects an inhibition of repair processes in the arterial wall. The enhancement of the arteriosclerosis may be explained by a decrease in the resistance of the aortic wall to mechanical trauma, possibly as a consequence of the effects of prednisone on the arterial mucopolysaccharides demonstrated in the present and the previous study. It is suggested, that the increased liability to skin-haemorrhages in patients given long-term treatment with glucocorticoids is due to an increased vascular fragility conditioned by the glucocorticoid-induced alterations in the mucopolysaccharides of the vascular wall.

Effects of methylprednisolone on plasma lipids and aortic mucopolysacchasrides of normal and cholesterol-fed rabbits.

SummaryMethylprednisolone (Medrol) was administered to normal and cholesterolfed rabbits for a period of 2 months, and its effects upon plasma cholesterol and triglyceride concentrations and upon the content of aortic acid mucopolysaccharides (AMPS) were studied. Rabbits fed a chow diet developed both a hypercholesterolemia and a hypertriglyceridemia in response to Medrol, and the already elevated cholesterol and triglyceride levels induced by cholesterol feeding were further elevated by Medrol. Despite the hyperlipemia, none of the Medrol-treated animals developed aortic atherosclerosis. Medrol had no significant effect upon the total aortic AMPS content in control animals but it did alter the aortic AMPS content and pattern of cholesterol-fed rabbits. The most significant effect was an increase in an AMPS of low sulfate content. Since all animals fed cholesterol developed some degree of pulmonary atherosclerosis, it is postulated that the antiatherogenic action of the hormone on the aorta is more closel...

Human aortic acid mucopolysaccharides and glycoproteins: Changes during ageing and in atherosclerosis

Summary Acid mucopolysaccharides (MPS) and glycoproteins from the intima and the media of 26 Japanese thoracic aortas were studied with emphasis on ageing and atherosclerosis. Total acid MPS significantly increased with age in the intima and slightly in the media; they decreased in both layers in the presence of atherosclerosis. Cellulose acetate electrophoresis was used to separate acid MPS into three fractions for analysis, namely hyaluronic acid, heparitin sulphate and chondroitin sulphates B and/or C. Changes in the compositional pattern of acid MPS with ageing or atherosclerosis were inconclusive. The total carbohydrate fraction of aortic intimai glycoproteins decreased until the age of 60 years, and increased thereafter, while the fraction from the media tended to increase progressively with age. The most conspicuous change in glycoprotein constituents in atherosclerosis was the marked fall in intimai sialic acid. Galactose, mannose and f ucose were identified as integral components of vascular glycoproteins in all preparations examined. However, an additional chromatographic spot that corresponded to glucose was detected in 2 cases.

Inhibition of dietary atherosclerosis in rabbits by norethynodrel

Summary Norethynodrel administered to rabbits reduces the atherogenicity of a cholesterol diet in part through its effect on serum cholesterol. There is an increase of the aortic acid mucopolysaccharides of the treated animals, an observation which contradicts the theory that such accumulations predispose to the occurrence and localization of lipid deposits.

Effects of estrogens on the metabolism of acid mucopolysaccharides in rat aorta

The effects of estrone, 2-methoxymethyl-17α-methylestradiol-3-methyl ether (P-5780) which is an anti-atherogenic lipid-shifting steroid, and testosterone propionate on the metabolism in vivo of aortic acid mucopolysaccharides (AMPS) in male Wistar rats were investigated. Results were compared with the effects of these compounds on costal cartilage and eyeball tissues. (1) The incorporation of sodium sulfate-S 35 into AMPS in costal cartilage was found to be more than the incorporation into aorta and eyeball. The specific activities in the aorta and eyeball were higher than in the cartilage. (2) In estrone-treated rats the specific activity of aortic AMPS was higher than those of cartilage and eyeball, while P-5780-treatment decreased the aortic AMPS level and incorporation into aortic AMPS without influencing the levels in cartilage and eyeball. Testesterone propionate had no effect on the aortic AMPS level but tended to decrease the incorporation into AMPS in the cartilage and eyeball. (3) In hypercholesterolemic rats the AMPS levels in the aorta and eyeball tended to decrease and incorporation into all connective tissues examined tended to decrease, while there was a significant increase in the specific activity of aortic AMPS. P-5780-treatment had no significant effect on the metabolism of AMPS in the aorta and other tissues of these treated animals. (4) On treatment with P-5780 the specific activity of perchloric acid soluble serum protein (glycoprotein) increased significantly but that of perchloric acid insoluble serum protein was unaffected. Estrone had no effect on the specific activities of either perchloric acid soluble or insoluble of serum protein.

Comparative studies on serum lipids and histochemical features of the arterial wall in animal species differently susceptible to experimental atherosclerosis

Summary Serum lipid pattern and aortic acid mucopolysaccharides content have been studied in ten animal species with different degrees of susceptibility to cholesterol-induced atherosclerosis. No significant correlation between serum lipid pattern and susceptibility to cholesterol-induced atherosclerosis has been demonstrated. On the contrary, a constant parallelism has been shown between the abovementioned susceptibility and the amount of aortic acid mucopolysaccharides. It is suggested that the arterial content of acid MPS might partially explain the species susceptibility to cholesterol-induced atherosclerosis.

Aortic Acid Mucopolysaccharides and Collagen in Scorbutic Guinea Pigs

After 4 weeks of receiving an ascorbic acid-deficient diet, otherwise healthy young guinea pigs displayed: an increase of total aortic acid mucopolysaccharides, essentially the result of increased hyaluronic acid content and a decrease of aortic collagen measured as hydroxyproline. These changes are similar to those observed in wound repair during scurvy, although they are quantitatively less. Collagen in the aortic wall was metabolically more active than it was in other body structures.

Possible relationship between aortic acid mucopolysaccharides and species-susceptibility to experimental atherosclerosis.

DIFFERENCES between species in susceptibility to experimental atherosclerosis is one of the most stimulating problems of atherogenesis. Animal species less susceptible to cholesterol-induced atherosclerosis showed a greater lipolytic activity of the arterial wall1–3 and a higher alpha-beta serum lipoprotein ratio4,5 than susceptible ones. Moreover, the thyroid gland was found to be more active in the former group than in the latter6–9.

ON THE EFFECT OF ATHEROSCLEROSIS AND GOITRE ON AORTIC HISTOPATHOLOGY AND MUCOPOLYSACCHARIDE CONTENT

ABSTRACT The effect of goitre on aortic mucopolysaccharides in sclerotic and nonsclerotic subjects was studied by histological and biochemical methods. Atherosclerosis alone lowers the quantity of aortic acid mucopolysaccharides. Goitre alone shows a tendency to increase the mucopolysaccharide content of the aorta. Goitre accelerates the effect of atherosclerosis in decreasing the aortic mucopolysaccharides, i. e. fibrosing and sclerosing effect. Histological observations reveal that atherosclerosis is characterized, in all groups, by fatty degeneration of intima and inner elastic membrane and destruction of the elastic connective tissue, and in the process of repair the mucopolysaccharides increase. In connection with the ensuing collagenization, the mucopolysaccharides decrease. It is suggested that goitre by hypo- or hyperfunction causes metabolic disturbances in the aortic wall and thus promotes atherosclerosis.