Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidemiologic studies have shown that insulin is a risk factor for coronary heart disease (CHD). Clinical studies have also demonstrated positive correlations between insulin and blood pressure, triglycerides, total cholesterol, fibrinogen, and plasminogen activator inhibitor. Moreover, there is an inverse correlation between insulin and high-density lipoprotein (HDL). These studies have provided evidence in support of the biologic plausibility of epidemiologic observations, but they have not clearly established insulin's role in the pathogenesis of human cardiovascular diseases (CVD) such as hypertension. In fact, there is considerable evidence that insulin resistance (abnormal nonoxidative glucose disposal), not hyperinsulinemia, is the primary insulin-related abnormality in human hypertension, and that hyperinsulinemia occurs as a response to insulin resistance. Skeletal muscle appears to be the primary site of insulin resistance in essential hypertension, although other organs, such as the kidneys and liver--key sites for cell and water homeostasis and lipoprotein regulation, respectively--may respond normally to insulin. Adipocytes also appear to be a site of insulin resistance. Thus, the putative interrelationship between hyperinsulinemia and insulin resistance, on the one hand, and with blood pressure and lipoproteins, on the other, is a complex one and may involve organ-specific insulin resistance. Altered cation transport is one of several mechanisms by which insulin resistance might raise blood pressure. The Na+, K(+)-ATPase and Ca(2+)-ATPase pumps are insulin sensitive. Thus, when insulin resistance is present, the activity of these pumps in the smooth muscle of the arterial wall might be reduced. This would lead to an intracellular accumulation of sodium and calcium, thereby sensitizing the vascular wall to pressor substances. Moreover, secondary hyperinsulinemia will occur, and insulin has been shown to stimulate sympathetic nervous system activity and to increase renal tubular absorption of sodium. Insulin is also a growth factor and therefore might have a trophic effect on the vessel wall, one that could initiate and/or sustain hypertension as well as atherosclerosis. Abnormal lipoprotein metabolism is yet another possible explanation for the accelerated atherosclerosis that has been observed in persons with abnormal carbohydrate tolerance and insulin resistance. Hyperinsulinemia and insulin resistance both play a role in the expression of elevated very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels as well as in the depression of HDL levels. Coronary risk reduction has been disappointing when blood pressure has been lowered with treatment regimens based on thiazide diuretics and/or beta blockers. Thiazides and some beta blockers may further impair tissue insulin sensitivity and often cause blood lipoprotein abnormalities.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Epidemiologic and clinical aspects of insulin resistance and hyperinsulinemia. 186 24

Randomly chosen medical charts of 212 elderly subjects in 11 nursing homes were reviewed to determine which characteristics of the subjects were most closely associated with their diet prescriptions. The chart reviews indicated that 104 (49.0%) of the 212 subjects had some type of nutrient-modified diet prescription. Eight patients who were tube fed were not included in subsequent analyses. Sodium restriction was the most common modification (60 [29.4%] of the remaining 204 patients) and calorie-controlled diets were also common (52 [25.5%] of the patients). Of the 55 patients with hypertension, 31 (56.4%) had no sodium restriction. Only 10% of all low-sodium diets limited sodium to 2 g per day. Of the 38 patients with diabetes, 7 (18.4%) had no prescription for calorie control, and there was no indication that increased dietary fiber was encouraged for diabetic patients. Only one of the 121 subjects with a diagnosis of coronary heart disease or atherosclerosis had a prescription for a cholesterol-lowering diet. Characteristics of the subjects not specifically related to diet or diagnosis, such as age, sex, duration of stay, and level of care, had no significant relationship to diet prescription. These findings suggest that the practitioners in our sample were not convinced of the efficacy of modified diets to control disease for most nursing home residents.
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PMID:Use of modified diets in nursing homes. 191 38

Cultured aortic smooth muscle cells from rabbit, in synthetic and contractile state, are considered good models for studying pathological and normal cells, respectively, during the atherosclerotic process. Cholesterogenic activity was compared in cells which were obtained in both states of the same subculture and incubated with labeled sodium acetate. This activity (expressed as the percentage of total cell radioactivity uptake transformed into cholesterol) was very high in synthetic cells and comparable to that of cancer cells. Cholesterol synthesis was lower in contractile cells and similar to that observed in a nonpathological cultured cell. During the cell life-span (studied in two cultures) cholesterogenic activity initially increased and then slowly decreased, in the two phenotypic states. Near the end of the culture life, cholesterol production drastically decreased, but this was due to a blocking of the last steps, lanosterol demethylation and C27 sterol transformation into cholesterol, rather than to a sharp decrease in the first steps of the cholesterogenic process. Cells in the synthetic and contractile states released newly synthesized lipids which were essentially late precursors of cholesterol, but accumulation of oxy-sterols was not observed. The excretion of metabolites increased with culture aging.
Atherosclerosis 1991 Feb
PMID:Active cholesterol biosynthesis in cultured aortic smooth muscle cells: evolution during the life-span of the culture. 187 7

We studied a 39-year-old man who had palmar xanthomas complicated with marked hyperlipidemia. His serum cholesterol and triglyceride were 2000 and 6300 mg/dl, respectively. Serum apolipoprotein E (apo E) was undetectable in the patient by the methods of single radial immunodiffusion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and radioimmunoassay. Serum apo E concentrations of his father and sister were low. This evidence is consistent with a diagnosis of familial apo E deficiency. We studied the synthesis of apo E in cultures of peripheral blood monocyte macrophages (M-M cultures) obtained from the patient, and detected no secretion of apo E in the culture medium and no newly synthesized apo E in the cell lysate. There were only trace amounts of apo E mRNA of the M-M cultures and the size of the mRNA appeared the same as normal apo E mRNA, indicating a different mutation of the gene from that of the case reported by Zannis et al. (J. Biol. Chem., 260 (1985) 12891).
Atherosclerosis 1991 May
PMID:Apolipoprotein E deficiency with a depressed mRNA of normal size. 187 6

Advances in regulation by secondary messengers of Ca2+ level in cardiomyocyte and vascular smooth muscle cell cytosols with special reference to the major differences in regulatory effects in cells of the both types are reviewed. The effects of cAMP, cGMP, Ca2+, calmodulin, diacylglycerol and polyphosphoinositides on the Ca(2+)-channel, Ca(2+)-ATPase, plasmalemma, sarcoplasmic reticulum and outer membrane Na+/Ca2+ uniporter function are considered. Compartmentation of secondary messengers and protein kinase in cardiac and vascular smooth muscle cells should be taken into consideration during extrapolation of in vitro data to an in situ situation. The feasible role of impaired phosphorylation of membrane-bound proteins of cardiac and vascular smooth muscle cells in cardiac insufficiency and atherosclerosis is discussed.
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PMID:[Second messengers in heart cells and smooth muscle vessels]. 191 66

Attenuation of acetylcholine-induced endothelium-dependent relaxation of thoracic aortas excised from Watanabe heritable hyperlipidemic (WHHL) rabbits linearly correlated with the percent area coated with atheromatous plaque. To elucidate mechanisms related to this reduced endothelium-dependent relaxation in the presence of atherosclerosis, the acetylcholine-induced release of endothelium-derived relaxing factor (EDRF) was assessed functionally as a percent relaxation of the precontracted detector strips obtained from the tunica media beneath the intact intima or the atheromatous plaque in the same aortic ring preparation. Relaxations of the normal detectors to effluents containing EDRF of thoracic aortas during stimulation by acetylcholine (3 x 10(-6) M) in heterozygous and homozygous WHHL rabbits were 73 +/- 5% and 59 +/- 9% (p less than 0.01) of the phenylephrine-induced precontraction, respectively. Relaxations of the atherosclerotic detectors to effluents (EDRF) through the aortas during stimulation by acetylcholine (3 x 10(-6) M) in heterozygous and homozygous WHHL rabbits were 16 +/- 4% and 14 +/- 5%, respectively--values significantly smaller than those seen in the normal detectors. When superoxide dismutase was added to the perfusate of the donors from homozygous and heterozygous WHHL rabbits, atherosclerotic detectors relaxed by effluents stimulated by acetylcholine to 73% and 65% (p less than 0.01 versus before the addition of superoxide dismutase) of the normal detector, respectively. Relaxations induced by sodium nitroprusside as well as the contractions by acetylcholine, phenylephrine, and KCl (118 mM) were comparable in detector strips from the normal and atherosclerotic portions. Thus, not only is the amount of EDRF released by acetylcholine reduced in the presence of atherosclerosis, the tunica media beneath the atheromatous plaque is also to some extent responsible for the superoxide-induced inactivation of EDRF.
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PMID:Putative mechanisms of the impairment of endothelium-dependent relaxation of the aorta with atheromatous plaque in heritable hyperlipidemic rabbits. 199 41

The functions of the endothelium and the effects of hypertension, atherosclerosis, and diabetes on the endothelium are reviewed. The endothelium affects vascular tone by releasing vasodilators and modulating the effects of vasoactive substances such as catecholamines, bradykinin, serotonin, and angiotensin II. Relaxation of vascular smooth muscle depends upon a functionally intact endothelium and the release of the endothelium-derived relaxing factor nitric oxide. Endothelial cells also appear to release a hyperpolarizing factor that relaxes smooth muscle through activation of the sodium-potassium pump, and of the endothelium-dependent contracting factors. Similarities are found in the vascular injury resulting from hypertension, atherosclerosis, and diabetes. When these risk factors coexist, they can act synergistically and magnify the vascular injury. The endothelium appears to be one of the major targets for these forms of injury. Future therapeutic strategies will focus on ways to prevent, arrest, or reverse endothelial injury.
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PMID:Hypertension, endothelium, and cardiovascular risk factors. 199 9

Adult rabbit smooth muscles contain two types of myosin heavy chain (MHC) isoforms, SM1 and SM2 which are generated through alternative RNA splicing from a single gene (Nagai, R., Kuro-o, M., Babij, P. & Periasamy, M. (1989) J. Biol. Chem. 264, 9734-9737). We previously reported that the expression of SM1 and SM2 during vascular development is differentially regulated at the level of RNA splicing, whereby SM1 is constitutively expressed from early development but SM2 appear after birth (Kuro-o, M., Nagai, R., Tsuchimochi, H., Katoh, H., Yazaki, Y., Ohkubo, A. & Takaku, F. (1989) J. Biol. Chem. 264, 18272-18275). We also demonstrated that embryonic vascular smooth muscles contain a third type of MHC isoform, referred to as SMemb in this report, which comigrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with SM2. In the present study we have isolated and characterized a cDNA clone (FSMHC34) for SMemb. FSMHC34 encodes the light meromyosin region including the carboxyl terminus and showed 70% amino acid sequence identity with SM1 or SM2. SMemb is a nonmuscle-type MHC and identical with brain MHC, but clearly distinct from 196-kDa nonmuscle MHC in cultured smooth muscle cells. The expression of SMemb was predominant in embryonic and perinatal aortas, but down-regulated with vascular development. Interestingly SMemb was reexpressed in proliferating smooth muscle cells of arteriosclerotic neointimas. These results suggest that smooth muscle proliferation is coupled to the expression of SMemb and that dedifferentiation of smooth muscles toward the embryonic phenotype is involved in the mechanisms underlying atherosclerosis.
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PMID:cDNA cloning of a myosin heavy chain isoform in embryonic smooth muscle and its expression during vascular development and in arteriosclerosis. 199 31

In chronic models of hypertension such as the spontaneously hypertensive rat (SHR), thickening of the media of large arteries occurs mainly through smooth muscle cell (SMC) hypertrophy accompanied by DNA replication resulting in large polyploid cells. In resistance vessels of SHR, medial hypertrophy occurs through a hyperplastic response. It has been suggested that this hyperplasia is due to mitogens such as platelet-derived growth factor (PDGF), while the hypertrophied polyploid cells occur from stimulation by angiotensin II from within the vessel wall. Angiotensin II activates many of the same cellular pathways as PDGF, including stimulation of phospholipase C, mobilization of intracellular calcium and activation of Na+/H+ exchange. Both induce transient increases in the proto-oncogenes c-fos and c-myc. However, a possible explanation for the difference in SMC response may be involvement of an intracellular pathway stimulated by PDGF (but not by angiotensin II), such as stimulation of JE (a cytokine-like molecule), which may activate transcriptional events necessary for mitogenesis. In atherosclerosis vascular hypertrophy occurs in the form of focal intimal thickening and results from hyperplasia of diploid SMC and their greatly increased production of extracellular matrix, (particularly collagen) and the accumulation of intra- and extracellular lipid. The SMC involved in atherogenesis are phenotypically modified compared with the SMC of undiseased regions, and amongst other features have a lower volume fraction of myofilaments (Vvmyo). Associated with modulation to a low Vvmyo are increases in SMC expression of mRNA for collagens type I (alpha 1 and alpha 2) and type III (alpha 1), elastin, fibronectin, as well as massive increases in collagen protein (26- to 45-fold), glycosaminoglycans (5-fold), and lipid accumulation (7-fold).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular biology of vascular hypertrophy. 203 94

Resistance to the action of insulin on glucose metabolism, with the ensuing compensatory hyperinsulinaemia, is closely linked to essential hypertension. The decreased insulin sensitivity observed in hypertensive patients is independent of obesity. Hyperinsulinaemia is likely to promote the dyslipidaemia that frequently accompanies the hypertensive state, and often presents as increased total and very low density lipoprotein (VLDL)-triglycerides, low high density lipoprotein (HDL)-cholesterol and, in some studies, elevated levels of low density lipoprotein (LDL)-cholesterol. Lipid abnormalities, hypertension and possibly hyperinsulinaemia act together to increase the risk of atherosclerotic disease manifestations in hypertensive patients. Acutely, insulin has been shown to stimulate sympathetic nervous system activity and transmembrane electrolyte transport, to promote sodium retention and to cause vascular wall changes, including increased cholesterol biosynthesis and smooth muscle proliferation. If these mechanisms operate on a chronic basis, the continuous exposure to elevated plasma insulin levels may play a pathogenetic role in the development of high blood pressure, and also of a predisposition toward atherosclerosis in patients with hypertension. Further studies are necessary to establish these hypothetical cause-effect relationship which, if shown to be true, will contribute to a more wide-ranging view of essential hypertension and the optimum strategy for antihypertensive treatment.
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PMID:Insulin resistance in hypertension--a relationship with consequences? 204 24


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