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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stimulating cardiac beta 1-adrenoceptors with oxyfedrine causes dilatation of coronary vessels and positive inotropic effects on the myocardium. beta 1-adrenergic agonists increase coronary blood flow in nonstenotic and stenotic vessels. The main indication for the use of the phosphodiesterase inhibitors pamrinone, mirinone, enoximone and piroximone is acute treatment of severe congestive heart failure. Theophylline is indicated for the treatment of asthma, chronic obstructive pulmonary disease, apnea in preterm infants ans sleep apnea syndrome. Severe arterial occlusive disease associated with atherosclerosis can be beneficially affected by elcosanoids. These drugs must be administered parenterally and have a half-life of only a few minutes. Sublingual or buccal preparations of nitrates are the only prompt method (within 1 or 2 min) of terminating anginal pain, except for biting nifedipine capsules. The short half-life (about 2.5 min) of nitroglycerin (glyceryl trinitrate) makes long term therapy impossible. Tolerance is a problem encountered with longer-acting nitric oxide donors. Knowledge of the pharmacokinetic properties of vasodilating drugs can prevent a too sudden and severe blood pressure decrease in patients with chronic hypertension. In considering the administration of a second dose, or another drug, the time necessary for the initially administered drug to reach maximal efficacy should be taken into account. In hypertensive emergencies urapidil, sodium nitroprusside, nitroglycerin, hydralazine and phentolamine are the drugs of choice, with the addition of beta-blockers during catecholamine crisis or dissecting aortic aneurysm. Childhood hypertension is most often treated with angiotensin-converting enzyme (ACE) inhibitors or calcium antagonists, primarily nifedipine. Because of the teratogenic risk involved with ACE inhibitors, extreme caution must be exercised when prescribing for adolescent females. The propagation of health benefits to breast-fed infants, combined with more women delaying pregnancy until their fourth decade, has entailed an increase in the need for hypertension management during lactation. Low dose hydrochlorothiazide, propranolol, nifedipine and enalapril or captopril do not pose enough of a risk of preclude breastfeeding in this group. The most frequently used antihypertensive agents during pregnancy are methyldopa, labetalol and calcium channel antagonists. Methyldopa and beta-blockers are the drugs of choice for treating mild to moderate hypertension. Prazosin and hydralazine are used to treat moderate to severe hypertension and hydralazine, urapidil or labetalol are used to treat hypertensive emergencies. The use of overly aggressive antihypertensive therapy during pregnancy should be avoided so that adequate uteroplacental blood flow is maintained. Methyldopa is the only drug accepted for use during the first trimester of pregnancy.
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PMID:Clinical pharmacokinetics of vasodilators. Part II. 967 32

The action of lipoprotein lipase on chylomicrons (CM) and very low density lipoproteins (VLDL) produces remnant lipoproteins (RLP) which are rich in triglycerides, cholesterol and apolipoprotein E (apo E). Apo E serves as a ligand for uptake of RLP by macrophages, platelets, endothelial cells and other cells expressing the LDL-receptor or the remnant receptor, thus having a major role in the clearance of plasma cholesterol and triglycerides, but at the same time, uptake of apo E-bearing RLP can profoundly alter the physiology of these cells and promote atherosclerosis. Like RLP, blood platelets also have roles in atherosclerosis and thrombosis, hence it is likely that RLP influence platelet activity as well. RLP derived from normal human plasma VLDL and CM were prepared using two monoclonal antibodies, anti-apo B-100 (JI-H) and anti-apo A-I (H-12) coupled to Sepharose 4B gel to form an immunoaffinity column. Lipoproteins containing apo B-100 including VLDL and LDL adsorb to (JI-H)-gel, while CM and HDL with apo A-I adsorb to (H-12)-gel. The particles in the unbound fraction (RLP) are rich in apo B-48, apo E and apo B-100 containing particles with multiple molecules of apo E. The RLP fraction with a total triglyceride of 14+/-3.2 mg/ml; cholesterol, 0.39+/-0.1 mg/ml and protein, 0.78+/-0.24 mg/ml (n=19) was added to aliquots of blood of man, rabbits, guinea pigs, mice, and rats at protein equivalents of 0.98 to 78 microg/ml blood and agitated gently at 37 degrees C for 40 sec. Platelet aggregation was measured as a fall in single platelet count. RLP induced aggregation of platelets in man (p<0.005) rabbit (p<0.0005), guinea pig (p<0.002) and mouse (p<0.0001), but no RLP induced platelet aggregation was observed in the rat blood. Scanning electron microscopy revealed that in the presence of RLP, platelets had adhered to and formed aggregates on red cells. The platelet response to RLP was inhibited by apyrase known to scavenge ADP, by 5 microM 2-chloroadenosine, a platelet ADP receptor antagonist and by 3.4 microM cilostazol, a phosphodiesterase type III inhibitor known to raise cyclic AMP level in platelets. It is thought that RLP cause leakage of ADP from red cells which then mediates platelet aggregation.
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PMID:Adenosine 5'-diphosphate as a factor in platelet aggregation induced by human plasma remnant lipoproteins. 974 29

Experiments were conducted to determine how selective inhibitors of certain cyclic nucleotide phosphodiesterase (PDE) families, namely CI-930 (PDE3 inhibitor; 3-(2H)-pyridazinone-4,5-dihydro-6-[4-(1H-imidazolyl) phenyl]-5-methyl monohydro chloride) and rolipram (PDE4 inhibitor), may affect human coronary artery smooth muscle cell (HCASMC) proliferation. CI-930- and rolipram-inhibitable PDEs accounted for most of the cyclic AMP hydrolyzing activity in HCASMC. Twenty micromolar CI-930 and 20 microM rolipram used individually attenuated proliferation of HCASMC from some, but not all donors, as measured by flow cytometry. The simultaneous addition of 10 microM CI-930 plus 10 microM rolipram caused greater attenuation. This attenuation represented a reduction of the number of cells entering the S phase of the cell cycle and not merely a delay in cell cycle traverse. No statistically significant elevation of cyclic AMP was detected following the addition of either PDE inhibitor individually, but the combination produced significant elevations. It is concluded that CI-930- and rolipram-inhibitable PDE isozymes are expressed in HCASMC and that selective inhibitors of these isozymes can attenuate HCASMC proliferation. The data suggest that selective PDE inhibitors may prevent restenosis in patients following percutaneous transluminal coronary angioplasty because of their effect on HCASMC proliferation, and they may also be useful in retarding the progression of atherosclerosis in individuals at risk. PDE3 and PDE4 inhibitors in combination are more effective than the inhibitors used individually.
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PMID:Effect of CI-930 [3-(2H)-pyridazinone-4,5-dihydro-6-[4-(1H-imidazolyl) phenyl]-5-methyl-monohydrochloride] and rolipram on human coronary artery smooth muscle cell proliferation. 977 20

The effect of milrinone, a phosphodiesterase (PDE) inhibitor, on intimal thickening after endothelial denudation was investigated. Intimal thickening was induced in the femoral arteries of mice by a photochemical reaction between rose bengal and transluminal green light which caused endothelial injury followed by platelet adhesion, aggregation, and formation of an occlusive thrombus in the irradiated segment of the mouse femoral artery. In this model, intimal thickening occurred following spontaneous thrombolysis. The intima/media ratio at 21 days after irradiation was 0.556+/-0.104 in the untreated group. Oral administration of milrinone (0.3-3.0 mg/kg) for 3-21 days suppressed intimal thickening by up to 56% in a dose- and time-dependent manner. In an in vivo experiment using bromodeoxyuridine incorporation, milrinone suppressed cell proliferation at 1.0 mg/kg p.o. On the other hand, the minimum doses of milrinone for suppression of ex vivo platelet aggregation induced by collagen (0.8 microg/ml) or ADP (0.5 microM) were 3.0 and 10.0 mg/kg, respectively. These results indicate that milrinone may not suppress intimal thickening by inhibiting platelet function but by preventing vascular smooth muscle cell (VSMC) proliferation, probably through a mechanism mediated via 3', 5'-adenosine cyclic monophosphate (cAMP).
Atherosclerosis 1999 Jan
PMID:Milrinone, a phosphodiesterase inhibitor, suppresses intimal thickening after photochemically induced endothelial injury in the mouse femoral artery. 992 May 14

Endothelium injury plays an important role in atherosclerosis. Damage to the endothelium results in vascular smooth muscle cell proliferation. Natriuretic peptides present a potent antimitogenic action, mediating their biological effects via the binding of guanylate cyclase-linked atrial natriuretic peptide (ANP) receptor and the production of cyclic GMP. In a previous study, we demonstrated that L-citrulline, the by-product of nitric oxide synthesis, could relax rabbit aortic rings by stimulating the guanylate cyclase-linked ANP receptor. In this work, we investigated the effect of L-citrulline on vascular smooth muscle cell proliferation. L-Citrulline (10(-8) M) significantly decreased rat aortic (A10 cell line) vascular smooth muscle proliferation. The percentage of inhibition exerted by L-citrulline on days 3, 5, and 7 of the proliferation curve was 20.0 +/- 0.5%, 37.5 +/- 8.3%, and 28. 5 +/- 7.2%, respectively. In addition, L-citrulline also inhibited serum-induced DNA synthesis, measured as 5-bromo-2'-deoxyuridine incorporation. 5-Bromo-2'-deoxyuridine incorporation into nuclei of vehicle-treated cells was 40.5 +/- 2.4%, whereas in L-citrulline-treated cells the percentage decreased to 36.0 +/- 4.1%, 29.1 +/- 2.0% (P <.01, n = 4), 30.5 +/- 2.4% (P <.05, n = 4), and 23.1 +/- 0.5% (P <.001, n = 4) for 10(-10), 10(-9), 10(-8), and 10(-7) M, respectively. Zaprinast, a phosphodiesterase type V inhibitor, enhanced 5-bromo-2'-deoxyuridine incorporation in serum-stimulated cells. Moreover, L-citrulline inhibition of serum-stimulated DNA synthesis was abolished by HS-142-1 (10(-5) M), an ANP receptor antagonist. In another group of experiments, L-citrulline was shown to increase intracellular cyclic GMP levels from 2.1 +/- 0.2 pmol of cGMP/mg protein to 4.1 +/- 0.1 for L-citrulline (10(-8) M) (P <.001, n = 3). These findings suggest that L-citrulline decreases vascular smooth muscle cell proliferation in the A10 cell line by acting on DNA synthesis by mechanisms that involve the ANP receptor.
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PMID:L-Citrulline, the by-product of nitric oxide synthesis, decreases vascular smooth muscle cell proliferation. 1038 92

Trapidil (triazolopyrimidine) is an antiplatelet agent that acts in part as a phosphodiesterase inhibitor and as a competitive inhibitor of the platelet-derived growth factor (PDGF) receptor. Trapidil has been shown to attenuate intimal hyperplasia in rat and hamster models of balloon arterial injury and to inhibit restenosis after percutaneous transluminal coronary angioplasty in several small clinical trials. Monocyte chemoattractant protein-1 (MCP-1) is a PDGF-inducible monocyte chemoattractant that is thought to play a particularly important role in recruiting monocyte/macrophages to sites of atherosclerosis and vessel injury. We hypothesized that, because of its ability to antagonize PDGF-mediated events, trapidil would inhibit the synthesis of MCP-1 and decrease macrophage accumulation in the injured arterial wall. Hypercholesterolemic rabbits were treated with trapidil (60 mg/kg/day subcutaneously) the day before and then daily for 6 days after balloon injury of the femoral artery; control rabbits received vehicle only. Trapidil resulted in a 75% reduction in MCP-1 expression and macrophage accumulation in the arterial wall 7 days after injury. This study suggests that trapidil has potent anti-inflammatory properties and that its activity in attenuating intimal hyperplasia may be in part attributed to its effects on macrophage accumulation.
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PMID:Trapidil inhibits monocyte chemoattractant protein-1 and macrophage accumulation after balloon arterial injury in rabbits. 1057 7

Viscum album L. has been used in the indigenous system of medicine for treatment of various diseases such as atherosclerosis and hypertension. In the literature, phenylpropan and flavonoid derivatives were suggested to play a role in the inhibition of cyclic adenosine monophosphate (cAMP)-phosphodiesterase (PDE) and a correlation was proposed between the in vitro inhibition of PDE and in vivo pharmacological activity. The vascular effects of the phenolic compounds and subfractions isolated from n-butanolic fraction of V. album ssp. album were studied on noradrenaline-contracted rat aortic rings. Isolated phenolic compounds (Syringin (VA-1), Coniferin (VA-9), 5, 7-dimethoxy-flavanone-4'-O-[beta-D-apiofuranosyl(1-->2)]-beta-D-gl uco pyranoside (VA-4)) produced concentration-dependent contractions in rat aortic rings. Only one compound (Kalopanaxin D (VA-15)) displayed very slight relaxant response. The weak concentration-dependent relaxing effect of the subfractions gave the idea that vasodilator activity were observed in the less polar subfractions. In addition, there was no clear correlation between the weak relaxant effects of subfractions and an inhibitory effect on cAMP-PDE.
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PMID:Studies on the vascular effects of the fractions and phenolic compounds isolated from Viscum album ssp. album. 1096 90

Cilostazol, a selective type III phosphodiesterase inhibitor, has antiplatelet and vasodilating effects. In this study, the effects of cilostazol on lipid metabolism and lipoprotein lipase (LPL) activity were studied in rats. Cilostazol was administered orally at doses of 30 or 100 mg/kg twice a day for 1-2 weeks to rats. Cilostazol decreased the serum triglyceride level in normolipidemic rats. The serum triglyceride level was reduced and HDL cholesterol level was increased by cilostazol in streptozotocin (STZ)-induced diabetic rats. The disappearance of exogenous triglyceride was accelerated by cilostazol in normolipidemic rats. Cilostazol increased post-heparin plasma LPL activity but had no effect on hepatic triglyceride lipase activity in STZ-induced diabetic rats. Cilostazol also increased LPL activity in the heart in STZ-induced diabetic rats. These findings suggest that an increase in LPL activity is responsible for the serum triglyceride lowering and HDL cholesterol elevating effects of cilostazol in rats.
Atherosclerosis 2000 Oct
PMID:Cilostazol, a selective type III phosphodiesterase inhibitor, decreases triglyceride and increases HDL cholesterol levels by increasing lipoprotein lipase activity in rats. 1099 57

The action of lipoprotein lipase on chylomicrons (CM) and very low density lipoproteins (VLDL) produces remnant lipoproteins (RLP) that are rich in triglycerides, cholesterol and apolipoprotein E (apo E). Apo E serves as a ligand for the LDL receptor and mediates uptake of RLP by macrophages, vascular wall and other cells that express the LDL receptor. Uptake of RLP can profoundly alter the physiology of cells and promote atherosclerosis and thrombosis. Like RLP, blood platelets also have roles in atherosclerosis and thrombosis; hence it is likely that RLP can influence platelet activity as well. Platelet aggregation was assessed by measuring the loss of single platelets. Apo E3/3-rich RLP derived from normal human plasma VLDL and CM were prepared by an immunoseparation method. At 2.5 to 10 microliters, RLP induced platelet aggregation that increased with the dose of RLP, but decreased it at 25 to 200 microliters. Unlike apo E3/3-rich RLP, apo E4/3 (heterozygous phenotype) rich RLP caused platelet aggregation in a dose-dependent manner, without producing a bell-shape dose-response relationship. Scanning electron microscopy revealed that activated platelets had adhered to and formed aggregates on the red cell membrane. The platelet response was unaffected by aspirin, but was inhibited by apyrase (an ADP scavenger), 2-chloroadenosine (a platelet ADP-receptor antagonist) and cilostazol, a phosphodiesterase type III inhibitor. It is thought that RLP cause leakage of ADP from red cells, which then mediates platelet aggregation.
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PMID:[Aggregation of human blood platelets by remnant-like lipoprotein particles]. 1121 76

Peripheral arterial disease affects approximately 8-10 million people in the United States. Approximately one-third to one-half of these individuals are symptomatic. The risk factors that contribute to peripheral arterial disease are similar to those associated with other forms of atherosclerosis, including diabetes mellitus, cigarette smoking, hypercholesterolemia, high blood pressure, and hyperhomocysteinemia. Of these, diabetes and cigarette smoking pose the greatest risk for developing peripheral arterial disease. The prognosis of patients with these risk factors is limited because of their greater risks for myocardial infarction, stroke, and cardiovascular death. Cardiovascular mortality correlates inversely with the ankle/brachial index, and the risk of death is greatest in those with the most severe peripheral arterial disease. Treatment regimens to reduce cardiovascular morbidity and mortality in patients with peripheral arterial disease should include risk factor modification and antiplatelet therapy. The cardinal symptoms of peripheral arterial disease include intermittent claudication and rest pain, with the latter being indicative of critical limb ischemia. Therapeutic strategies that focus on improving the patient's quality of life, reducing the severity of claudication, and improving limb viability include supervised exercise training, pharmacotherapy, and revascularization. Two drugs-pentoxifylline and cilostazol-currently are approved by the Food and Drug Administration for the treatment of patients with claudication. Meta-analyses have suggested that, compared with placebo, pentoxifylline improves maximal walking distance by approximately 20-25%. Cilostazol is a phosphodiesterase type 3 inhibitor. In clinical trials, cilostazol has consistently improved maximal walking distance as compared with placebo, with the range of improvement being approximately 40-60%. Drugs that are currently under investigation include propionyl-L-carnitine, vasodilator prostaglandins, L-arginine, and the angiogenic factors, vascular endothelial growth factor and basic fibroblast growth factors.
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PMID:Medical management of peripheral arterial disease. 1140 4


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