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)

Prostanoids are cyclic lipid mediators which arise from enzymic cyclooxygenation of linear polyunsaturated fatty acids, e.g. arachidonic acid (20:4 n 6, AA). Biologically active prostanoids deriving from AA include stable prostaglandins (PGs), e.g. PGE(2), PGF(2alpha), PGD(2), PGJ(2) as well as labile prostanoids, i.e. PG endoperoxides (PGG(2), PGH(2)), thromboxane A(2) (TXA(2)) and prostacyclin (PGI(2)). A "Rabbit aorta Contracting Substance" (RCS) played important role in discovering of labile PGs. RCS was discovered in the Vane's Cascade as a labile product released along with PGs from the activated lung or spleen. RCS was identified as a mixture of PG endoperoxides and thromboxane A(2). Stable PGs regulate the cell cycle, smooth muscle tone and various secretory functions; they also modulate inflammatory and immune reactions. PG endoperoxides are intermediates in biosynthesis of all prostanoids. Thromboxane A(2) (TXA(2)) is the most labile prostanoid (with a half life of 30 s at 37 degrees C). It is generated mainly by blood platelets. TXA(2) is endowed with powerful vasoconstrictor, cytotoxic and thrombogenic properties. Again the Vane's Cascade was behind the discovery of prostacyclin (PGI(2)) with a half life of 4 min at 37 degrees C. It is produced by the vascular wall (predominantly by the endothelium) and it acts as a physiological antagonist of TXA(2). Moreover, prostacyclin per se is a powerful cytoprotective agent that exerts its action through activation of adenylate cyclase, followed by an intracellular accumulation of cyclic-AMP in various types of cells. In that respect PGI(2) collaborates with the system consisting of NO synthase (eNOS)/nitric oxide free radical (NO)/guanylate cyclase/cyclic-GMP. Both cyclic nucleotides (c-AMP and c-GMP) act in synergy as two energetic fists which defend the cellular machinery from being destroyed by endogenous or exogenous aggressors. Recently, a new partner has been recognized in this endogenous defensive squadron, i.e. a system consisting of heme oxygenase (HO-1)/carbon monoxide (CO)/biliverdin/biliverdin reductase/bilirubin. The expanding knowledge on the pharmacological steering of this enzymic triad (PGI(2)-S/eNOS/HO-1) is likely to contribute to the rational therapy of many systemic diseases such as atherosclerosis, diabetes mellitus, arterial hypertension or Alzheimer diseases. The discovery of prostacyclin broadened our pathophysiological horizon, and by itself opened new therapeutic possibilities. Prostacyclin sodium salt and its synthetic stable analogues (iloprost, beraprost, treprostinil, epoprostenol, cicaprost) are useful drugs for the treatment of the advanced critical limb ischemia, e.g. in the course of Buerger's disease, and also for the treatment of pulmonary artery hypertension (PAH). In this last case a synergism between prostacyclin analogues and sildenafil (a selective phosphodiesterase 5 inhibitor) or bosentan (an endothelin ET-1 receptor antagonist) points our to complex mechanisms controlling pulmonary circulation. At the Jagiellonian University we have demonstrated that several well recognised cardiovascular drugs, e.g. ACE inhibitors (ACE-I), statins, some of beta-adrenergic receptor antagonists, e.g. carvedilol or nebivolol, anti-platelet thienopyridines (ticlopidine, clopidogrel) and a metabolite of vitamin PP--N(1)-methyl-nicotinamide--all of them are endowed with the in vivo PGI(2)-releasing properties. In this way, the foundations for the Endothelial Pharmacology were laid.
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PMID:Prostacyclin among prostanoids. 1827 80

Cigarette smoking is a recognized risk factor for cardiovascular diseases and has been implicated in the pathogenesis of atherosclerosis and thrombotic events. In athero-thrombotic diseases, the extracellular adenine nucleotides play an important role by triggering a range of effects such as the recruitment and activation of platelets, endothelial cell activation and vasoconstriction. NTPDase, a plasma membrane-bound enzyme, is the most relevant enzyme involved in the hydrolysis of extracellular tri- and di-phosphate nucleotides to adenosine monophosphate, which is further degraded by 5'ectonucleotidase to the anti-thrombotic and anti-inflammatory mediator adenosine. Thus, the preserved activity of these enzymes, regulating the extracellular concentrations of nucleotides, is critical in thromboregulatory functions. In the present in vitro study, performed on human platelets suspended in undiluted or diluted aqueous cigarette smoke extract (aCSE), we demonstrated that undiluted and 1 : 2 diluted aCSE is able to significantly reduce ADP hydrolysis (-24% and 12%, respectively) by intact human platelets. ATP degradation was also reduced (-31%) by undiluted aCSE. Conversely, aCSE did not alter platelet AMP hydrolysis. Results obtained by using N-acetylcysteine, a thiol-containing antioxidant, suggest that stable oxidants present in aCSE are responsible for the platelet NTPDase inhibition induced by aCSE. The decreased adenine nucleotide degradation could play a significant role in the extensive platelet activation and vascular inflammation observed in chronic smokers.
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PMID:Cigarette smoke inhibits adenine nucleotide hydrolysis by human platelets. 1897 66

Internalization of modified low-density lipoprotein (LDL) via macrophage scavenger receptors (e.g. scavenger receptor A and CD36) is thought to play a crucial role in the development of atherosclerotic lesions. Cilostazol, an antiplatelet agent with selective phosphodiesterase 3 inhibitory action, has been reported to ameliorate atherosclerosis in mouse models. However, the effect of cilostazol on modified LDL uptake in macrophages is not known. Thus, we investigated the effect of cilostazol on LDL uptake in mouse peritoneal macrophages (MPM). Cilostazol significantly inhibited oxidized and acetylated LDL uptake in MPM, while cyclic AMP (cAMP)-elevating agents, db-cAMP and other phosphodiesterase 3 or 4 inhibitors, did not inhibit the uptake. Cilostazol did not change cytosolic cAMP levels in MPM, and a protein kinase A (PKA) inhibitor did not influence the inhibitory effects of cilostazol. Cilostazol decreased scavenger receptor A but not CD36 expression. Moreover, cilostazol significantly inhibited foam cell formation, which was represented by an increase in esterified cholesterol content. In conclusion, cilostazol significantly inhibits the uptake of modified LDL and foam cell formation in mouse peritoneal macrophages, and the inhibitory effect of cilostazol can be induced in a cAMP- and PKA-independent manner.
Atherosclerosis 2009 Jun
PMID:Cilostazol inhibits modified low-density lipoprotein uptake and foam cell formation in mouse peritoneal macrophages. 1910 34

Extrarenal calcifications, particularly affecting the cardiovascular system, are common observations which can be a source of serious complications in patients with chronic renal disease, especially those on dialysis. In these patients, cardiovascular disease - myocardial infarction, arrhythmia, calcified valvulopathy, stroke, peripheral ischemic arteriopathy, calciphylaxy, etc. - is the leading cause of death (more than 50%). These complications are closely related to the presence of vascular calcifications (VC) which are much more frequent, severe, and progressive than in the general population. Previously, these calcifications were considered to arise via a passive process within the context of comorbid conditions without specific signs of gravity: high blood pressure, atherosclerosis, aging, diabetes, smoking, dyslipidemia, chronic micro-inflammation, hyperhomocysteinemia, disorders of calcium-phosphorus metabolism. It is now established that VC arise via a complex, probably regulated, active process analogous to the processes leading to bone formation and/or remodeling. New insight provided by a large body of work designed to ascertain the mechanisms underlying the onset of VC has enabled the development of new diagnostic and therapeutic approaches. It is now possible to identify factors clearly favoring the formation of VC: TNF-alpha (which stimulates cell necrosis/apoptosis), CRP, oxidized lipids, AGEs, leptin, inorganic phosphate, high calcium-phosphorus product (CaxPO(4)), calcium, 1,25-OH(2)D(3) and Vitamin D(3), PTHrP (via an intracrine pathway), cyclic AMP, TGF-beta, bone morphogenic protein 2 (BMP2) and factors protective against the formation of VC: magnesium, HDL, inorganic pyrophosphate, albumin, ahsg/fetuin A, osteopontin (OPN), osteoprotegerin (OPG), osteonectin (ON), bone morphogenic protein 7 (BMP7), klotho, PTHrP (via a paracrine pathway), matrix gla protein (MGP), PTH (via Msx2) and vitamin K. In conclusion, until recently, neglected disorders of calcium-phosphorus metabolism are currently recognized as the main actors in the process leading to vascular mediacalcosis in patients with chronic kidney failure.
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PMID:[Origin of the mediacalcosis in kidney failure]. 1934 26

AMPK (AMP-activated protein kinase) is a key regulator of cellular energy because of its capacity to detect changes in the concentration of AMP. Recent evidence, however, indicates the existence of alternative mechanisms of activation of this protein. Mitochondrial ROS (reactive oxygen species), generated as a result of the interaction between nitric oxide and mitochondrial cytochrome c oxidase, activate AMPKalpha1 in HUVECs (human umbilical-vein endothelial cells) at a low oxygen concentration (i.e. 3%). This activation is independent of changes in AMP. In the present study we show, using HUVECs in which AMPKalpha1 has been silenced, that this protein is responsible for the expression of genes involved in antioxidant defence, such as manganese superoxide dismutase, catalase, gamma-glutamylcysteine synthase and thioredoxin. Furthermore, peroxisome proliferator-activated-coactivator-1, cAMP-response-element-binding protein and Foxo3a (forkhead transcription factor 3a) are involved in this signalling pathway. In addition, we show that silencing AMPKalpha1 in cells results in a reduced mitochondrial and eNOS (endothelial NO synthase) content, reduced cell proliferation, increased accumulation of ROS and apoptosis. Thus AMPKalpha1 in HUVECs regulates both their mitochondrial content and their antioxidant defences. Pharmacological activation of AMPKalpha1 in the vascular endothelium may be beneficial in conditions such as metabolic syndrome, Type 2 diabetes and atherosclerosis, not only because of its bioenergetic effects but also because of its ability to counteract oxidative stress.
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PMID:AMPKalpha1 regulates the antioxidant status of vascular endothelial cells. 1944 39

In 1983, a delayed and prolonged cardioprotection induced by drugs was described. This pharmacologically induced adaptation to stress represents a new trend in cardioprotection as opposed to the classical drug treatment that was based on the presence of drug-receptor binding. Such a long-lasting, delayed adaptation can be induced by non-injurious pharmacological stimuli (eg, prostacyclin and its stable analogues, catecholamines and other substances) and manifests as a marked protection against the severe consequences of ischemia; attenuation of early morphological changes (limitation in infarct size) and reduction in ventricular arrhythmias as results of coronary artery occlusion and reperfusion or ouabain toxication. The protection is time- and dose-dependent; the maximum effects occur 24 h and 48 h after drug treatment. These effects can be prolonged for a longer period by the periodic administration of maintenance doses. Concerning the mechanism of this marked delayed protection, the findings show that these adaptive stresses stimulate the adenylate cyclase/cyclic AMP (cAMP) system and result in elevation in cardiac cAMP level. This triggers the induction of Na(+)/K(+)-ATPase and activates phosphodiesterase (PDE) isoforms, most likely PDE1 and PDE4. The increased amount of PDE isoforms and activated Na(+)/K(+)-ATPase moderates ischemic myocardial potassium loss, and reduces sodium and calcium accumulation during myocardial ischemia. This also attenuates ouabain toxicity. Induction of PDE isoforms may lead to a reduction in the accumulation of excess cAMP and contribute to a lessened response to beta-adrenergic stimuli. The antiarrhythmic effects can be explained by electrophysiological changes, such as prolongations of the effective refractory period and the action potential duration during ischemia and reperfusion. The advantages of pharmacologically induced adaptation to stress in preventive therapy are that an exact dosage can be applied, the risk of the harmful effects is minimal, the protection can be prolonged, and it can be induced under pathological conditions (eg, atherosclerosis, hypercholesterolemia). Pharmacologically induced long-term protection may represent a new approach in the therapy of cardiovascular diseases.
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PMID:Pharmacological induction of delayed and prolonged cardiac protection: The role of prostanoids. 1964 89

Octacosa-10,19-dien-1-ol is a newly synthesized long-chain alcohol, an unsaturated analogue of 1-octacosanol, the major component of policosanol, the purified natural mixture of different higher aliphatic alcohols obtained from sugarcane wax. Our efficient synthetic protocol (five steps with 50% overall yield) is well suited for gram scale preparations and a rapid generation of analogues with different degrees of unsaturation. Beneficial effects of policosanol in the prevention of atherosclerosis and thromboembolic disorders have been reported and related to the inhibition of sterol biosynthesis possibly by the regulation of the activity of HMGCoA reductase mediated by AMP-dependent kinase AMPK. We have compared the effect of octacosadienol and policosanol on the regulation of HMGCoA reductase in HUVEC and HepG2 human hepatoma cells. Octacosadienol was as effective as policosanol in inhibiting the upregulation of HMGCoA reductase, in inducing the phosphorylation of AMPK and in downregulating the HMGCoA reductase mRNA.
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PMID:Regulation of HMGCoA reductase activity by policosanol and octacosadienol, a new synthetic analogue of octacosanol. 1976 55

Increased Very Low Density Lipoprotein (VLDL) production is a major feature of diabetic dyslipidemia with consequences on the metabolism of other lipoproteins such as Low Density Lipoproteins (LDL) and High Density Lipoproteins (HDL). More precisely, we observe, in patients with type 2 diabetes, an increased production of VLDL(1) particles that is potentially detrimental by generating atherogenic remnants, small dense LDL particles and triglyceride-rich HDL particles. Several pathophysiological factors are responsible for increased VLDL production, in type 2 diabetes. Among those, insulin resistance plays an important role. Indeed, defective activation of PI3-kinase, secondary to insulin resistance, is associated with a reduction of apoB degradation in the hepatocytes, a rise in MTP expression (by increasing nuclear transcription factors Fox01 and Foxa2) and an increased activity of phospholipase D1 and ARF-1, which are involved in VLDL(1) formation. Moreover, peripheral insulin resistance is responsible for increased lipolysis of adipose tissue leading to augmented portal flux of FFA to the liver and, as a consequence, activation of VLDL production. In addition, increased de novo lipogenesis is observed in type 2 diabetes. This is secondary to increased activation of SREBP-1c (Sterol Regulatory Element-Binding Protein-1c), mainly by Endoplasmic Reticulum stress, and of ChREBP (Carbohydrate Responsive Element Binding Protein), mainly by hyperglycemia. Furthermore, decreased plasma adiponectin observed in type 2 diabetes, may also play a role in increased VLDL production by decreasing liver AMP-kinase activation and by increasing plasma FFA levels as a consequence of reduced muscle FFA oxidation.
Atherosclerosis 2010 Aug
PMID:Abnormal hepatic apolipoprotein B metabolism in type 2 diabetes. 2018 75

To evaluate the pharmacological properties of cilostazol (CLZ), we examined its intraocular pressure (IOP) -lowering effect. CLZ is an inhibitor of Type III phosphodiesterase that increases intracellular cyclic AMP levels by restraining platelet aggregation, and has a potential protective effect against atherosclerosis. We attempted to apply it for use as an anti-glaucoma agent; however, the application of CLZ in the ophthalmic field is limited due to its poor water solubility. We attempted to enhance CLZ solubility using 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). The solubility of CLZ increased with increasing HPbetaCD concentrations, and 0.05% CLZ was dissolved in 10% HPbetaCD. Moreover, fine particle suspension of 0.5% CLZ in 5% HPbetaCD (soluble CLZ: ca. 0.027%) were prepared using a Microfluidizer, an impact-type emulsifying comminution device. In an in vitro transcorneal penetration experiment through the rabbit cornea, the CLZ penetration rate was dependent on the CLZ content of the solutions and suspensions. When a 0.05% CLZ ophthalmic solution was instilled into a rabbit eye, the absorption rate constant for CLZ into an aqueous humor was 0.0059+/-0.001 min(-1), and the elimination rate constant was 0.048+/-0.024 min(-1). Also CLZ ophthalmic solutions and fine particle suspension were examined to for their ability to reduce enhanced intraocular pressure (IOP) of rabbits in a darkroom. The instillation of 0.05% CLZ ophthalmic solutions and 0.5% CLZ fine particle suspensions into rabbit eyes reduced the enhanced IOP. These results demonstrate that the instillation of CLZ ophthalmic solutions and fine particle suspensions may represent an effective anti-glaucoma formulation.
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PMID:Preparation of ophthalmic formulations containing cilostazol as an anti-glaucoma agent and improvement in its permeability through the rabbit cornea. 2062 34

Adenosine and adenosine derivatives are the main regulators of purinoceptors (P1 and P2) mediated hemostasis and blood pressure. Since impaired hemostasis and high blood pressure lead to atherosclerosis and to the development of aneurysm, in this study we tested and compared the concentration of extracellular purines (e-purines) in the blood in of patients having abdominal aortic aneurysm with that from healthy volunteers. Whereas adenine nucleosides and nucleotides level in human blood plasma was analysed using reverse phase high performance liquid chromatography (HPLC), cholesterol concentration was estimated by an enzymatic assay. We did not find any correlation between e-purines concentration and the age of healthy volunteers. Furthermore, the sum level of e-purines (ATP, ADP, AMP, adenosine, and inosine) in the control group did not exceed 70 microM, while it was nearly two-fold higher in the blood of patients having abdominal aortic aneurysm, (123 microM). In a special case of people with Leriche Syndrome, a disease characterized by deep atherosclerotic changes, the e-purines level had further increased. Additionally, we also report typical atherosclerotic changes in the aorta using histological assays as well as total cholesterol rise. The significant rise in cholesterol concentration in the blood of the patients with abdominal aortas aneurysm, compared with the control groups, was not unique since 23% of the healthy people also exceeded the normal level of cholesterol. Therefore, our results strongly indicate that the estimation of e-purines concentration in the blood may serve as another indicator of atherosclerosis and warrant further consideration as a futuristic diagnostic tool.
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PMID:Extracellular-purine metabolism in blood vessels (part I). Extracellular-purine level in blood of patients with abdominal aortic aneurysm. 2070 56


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