Rabbit, cholesterol

Diseases. Liquid crystals have been impHcated in a number of disease conditions in the human body. A complex cholesterol—phosphoHpid—Hpoprotein Hquid crystal phase has been identified in the initiation and maintenance of atheromatous deposits on the aortic intima in dissected human and rabbit arteries (40). The paracrystalHne nature of this precursor to plaque buildup with the resultant loss of arterial elasticity... 

YAMAKOSHi J, KTAOKA s, KOGA T, ARiGA T (1999) Proanthocyanidin-rich extract from grape seed attenuates the development of aortic atherosclerosis in cholesterol-fed rabbits, Atherosclerosis, 142, 139-49. 

Del Boccio, C., Laprenna, D., Porreca, E., Pennilli, A., Savini, F., Feliciani, P., Ricci, G. and CuccuruUo, F. (1990). Aortic antioxidant defence mechanisms time-related changes in cholesterol fed rabbits. Atherosclerosis 81, 127-135. 

Mu e, A., Elwell, J.H., Peterson, T.E., Hofmeyer, T.G., Heistad, D.D. and Harrison D.C. (1991). Chronic treatment with PEG-SOD partially restores endothelium dependent vascular relaxations in cholesterol fed rabbits. Circ. Res. 69, 1293-1300. 

Keaney, J.F., Gaziano, J.M., Xu, A., Frei, B., Curran-Celentano, J., Shwaery, G.T., Loscalzo, J. and Vita, J.A. (1994). Low dose a-tocopherol improves and high-dose a-tocopherol worsens endothelial vasodilator funrtion in cholesterol-fed rabbits. J. Clin. Invest. 93, 844-851. 

Proulx [30] summarized the published lipid compositions of BBM isolated from epithelial cells from pig, rabbit, mouse and rat small intestines. Table 3.1 shows the lipid make-up for the rat, averaged from five reported studies [30], On a molar basis, cholesterol accounts for about 50% of the total lipid content (37% on a weight basis). Thus, the cholesterol content in BBM is higher than that found in kidney epithelial (MDCK) and brain endothelial cells (Table 3.1). Slightly different BBM lipid distribution was reported by Alcorn et al. [31] here, the outer (luminal) leaflet of the BBM was seen to be rich in sphingomyelin content, while the inner leaflet (cytosol) was rich in PE and PC. Apical (brush border) and basolateral lipids are different in epithelia. The basolateral membrane content (not reported by... 

The expression of 15-LOX in atherosclerotic lesions is one of the major causes of LDL oxidative modification during atherosclerosis. To obtain the experimental evidence of a principal role of 15-LOX in atherosclerosis under in vivo conditions, Kuhn et al. [67] studied the structure of oxidized LDL isolated from the aorta of rabbits fed with a cholesterol-rich diet. It was found that specific LOX products were present in early atherosclerotic lesions. On the later stages of atherosclerosis the content of these products diminished while the amount of products originating from nonenzymatic lipid peroxidation increased. It was concluded that arachidonate 15-LOX is of pathophysiological importance at the early stages of atherosclerosis. Folcik et al. [68] demonstrated that 15-LOX contributed to the oxidation of LDL in human atherosclerotic plaques because they observed an increase in the stereospecificity of oxidation in oxidized products. Arachidonate 15-LOX is apparently more active in young human lesions and therefore, may be of pathophysiological importance for earlier atherosclerosis. In advanced human plaques nonenzymatic lipid peroxidation products prevailed [69],... 

Fig. 9.5. Protection by SERMs against atherosclerosis has been researched in animals. In a model of ovariectomized rabbits, raloxifene reduced the cholesterol content in the inner part of the aorta more than placebo did (upper panel). This effect was more intense in animals treated with estradiol (Bjarnason et al. 1997). In contrast, in a different model of oophorectomized monkeys (lower panel), estradiol, and not raloxifene at two different dosages, significantly decreased the size of atherosclerotic plaques (Clarkson et al. 1998)...

Bjarnason NH, Haarbo J, Byrjalsen I, Kauffman RF, Christiansen C (1997) Raloxifene inhibits aortic accumulation of cholesterol in ovariectomized, cholesterol-fed rabbits. Circulation 96 1964-1969... 

Raloxifene and estrogen reduces progression of advanced atherosclerosis -a study in ovariectomized, cholesterol-fed rabbits. Atherosclerosis 154 97-102... 

Haarbo J, Hansen BF, Christiansen C (1991) Hormone replacement therapy prevents coronary artery disease in ovariectomized cholesterol-fed rabbits. APMIS 99 721-727... 

Haines CJ, James AE, Panesar NS, Ngai TJ, Sahota DS, Jones RL, Chang AM (1999) The effect of percutaneous oestradiol on atheroma formation in ovariectomized cholesterol-fed rabbits. Atherosclerosis 143 369-375... 

Hough J L, Zilversmit DB (1986) Effect of 17 beta estradiol on aortic cholesterol content and metabolism in cholesterol-fed rabbits. Arteriosclerosis 6 57-63... 

Dai SL, Duan JH, Lu Y, Zhang YH, Cheng JX, Ren J, Zhao XY, Wu YQ, Yu Y, Zuo PP, Wu YY, Ge QS (2004) Phytoestrogen alpha-zearalanol inhibits atherogenesis and improves lipid profile in ovariectomized cholesterol-fed rabbits. Endocrine 25 121-129 Diekman MA, Green ML (1992) Mycotoxins and reproduction in domestic livestock. J Anim Sci... 

Recently nicotinic acid has been found to lower serum cholesterol in hypercholesteremia, and also in normal persons and rabbits (A3, F2). It was shown that the hypercholesteremia, induced by a 48-hour fast, could be completely corrected by giving the animals large doses of nicotinic acid during the fast. In contrast to nicotinic acid, nicotinamide does not lower the cholesterol level (M10). Several explanations are offered for the action of nicotinic acid (1) it inhibits cholesterol biosynthesis, (2) it interferes with coenzyme A, and (3) it involves a hitherto unknown pharmacologic effect. The renewed clinical interest in nicotinic acid induced us to look for a more specific and sensitive assay for nicotinic acid (B7, M8). 

The standard diet used in our experiments is a semipurified, cholesterol-free preparation that is composed of 25% protein, 40% sucrose, 13% coconut oil, 1% corn oil, 15% cellulose, 5% mineral mix, and 1% vitamin mix. This diet has been shown to induce an endogenous hypercholesterolemia and lead to atherosclerosis in rabbits and monkeys (4, 5). The specific question addressed by our series of investigations is whether the type of dietary protein, when all other dietary components are constant, can influence the development of hyperlipoproteinemia and atherosclerosis. More specifically, we have examined the effects of the individual amino acids, lysine and arginine, and their ratios in the diet on plasma and hepatic lipids as well as the development of arterial plaques. 

Number of Treatment Rabbits Serum Lipids (mg/dl) Atherosclerosis Cholesterol Triglycerides Arch Thoracic ... 

Table IV. Serum Cholesterol Levels in Rabbits fed Different...

Table V. Serum Cholesterol Levels in Rabbits fed Casein, Soy Protein, Their Hydrolysates and Their Amino Acid Mixtures...

In addition to more rapid absorption of lipids in animals fed casein, another mechanism that may be operative is decreased clearance of circulating lipids. Rabbits fed a casein-based semipurified diet excreted significantly less cholesterol but more bile acids in their feces than animals fed a commercial diet (18). The total sterol excretion in feces of the animals fed the casein diet was half that of the rabbits fed the stock diet. Huff and Carroll (19) found that rabbits fed soy protein had a much faster turnover rate of cholesterol and a significantly reduced rapidly exchangeable cholesterol pool compared with rabbits fed casein. Similar studies performed in our laboratory revealed that the mean transit time for cholesterol was 18.4 days in rabbits fed soy protein, 36.8 days in rabbits fed casein, 33.7 days in rabbits fed soy plus lysine, and 36.3 days in rabbits fed casein plus arginine. These data suggest that addition of lysine to soy protein... 

Figure 4 Transverse scan of axillary and subscapular lymph nodes in a rabbit 5 min postinjection of Gd-containing liposomes. Liposomes (egg lecithin cholesterol Gd-poly-NGPE = 70 25 5, 20 mg total lipid) were injected subcutaneously into the forepaw of anesthesized rabbit in 0.5 mL of HEPES-buffered saUne. Images were acquired by using a 1.5 Tesla GE Signa MRl scanner operated at fat suppression mode and Tj-weighted pulse sequence [16].

A series of iomeprol-containing liposomes were evaluated in animals by Petersein et al. [62] and in healthy volunteers by Spinazzi et al. [63,64]. BR2 and BR21 are liposomes made of phosphatidyl choline (PC),dipalmitoyl phospatidic acid (DPPA) and cholesterol at a molar ratio of 2 1 (PC -i- DPPA/cholesterol) with an iodine content of 260 mg mL (BR2) and 320 mg mL" (BR21), respectively, and a size of 0.4 pm. BR2 contains 40 mg lipid mL and BR21 20 mg mL L In rabbits, BR2 tended to provide a higher and more persistent CT enhancement than BR21. 

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