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Rodolfo Paoletti

Publications and source records attributed to Rodolfo Paoletti.

29 records · Page 2Linked to original sources
PubMed2003

Impact of statins on novel risk markers.

Long-and-short term trials with the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have demonstrated significant reductions in cardiovascular and cerebrovascular events in patients with and without preexisting heart disease. Beyond improving the lipid profile, statins have additional effects that may contribute to their overall clinical benefit. Statin treatment appears to reduce global risk profile by affecting both novel and established lipid, inflammatory, and morphologic markers including low-density lipoprotein subclasses, lipoprotein (a), markers of endothelial function, inflammatory mediators, intima-media thickening, and coronary calcification. Although statins may be regarded as a rather homogeneous drug class in terms of biological activity, some agents feature unique properties that have beneficial effects on selected important risk matters.

Animals↗
PubMed2003

Ajoene, a garlic compound, inhibits protein prenylation and arterial smooth muscle cell proliferation.

(1) Ajoene is a garlic compound with anti-platelet properties and, in addition, was shown to inhibit cholesterol biosynthesis by affecting 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase and late enzymatic steps of the mevalonate (MVA) pathway. (2) MVA constitutes the precursor not only of cholesterol, but also of a number of non-sterol isoprenoids, such as farnesyl and geranylgeranyl groups. Covalent attachment of these MVA-derived isoprenoid groups (prenylation) is a required function of several proteins that regulate cell proliferation. We investigated the effect of ajoene on rat aortic smooth muscle cell proliferation as related to protein prenylation. (3) Cell counting, DNA synthesis, and cell cycle analysis showed that ajoene (1-50 micro M) interfered with the progression of the G1 phase of the cell cycle, and inhibited rat SMC proliferation. (4) Similar to the HMG-CoA reductase inhibitor simvastatin, ajoene inhibited cholesterol biosynthesis. However, in contrast to simvastatin, the antiproliferative effect of ajoene was not prevented by the addition of MVA, farnesol (FOH), and geranylgeraniol (GGOH). Labelling of smooth muscle cell cellular proteins with [3H]-FOH and [3H]-GGOH was significantly inhibited by ajoene. (5) In vitro assays for protein farnesyltransferase (PFTase) and protein geranylgeranyltransferase type I (PGGTase-I) confirmed that ajoene inhibits protein prenylation. High performance liquid chromatography (HPLC) and mass spectrometry analyses also demonstrated that ajoene causes a covalent modification of the cysteine SH group of a peptide substrate for protein PGGTase-I. (6) Altogether, our results provide evidence that ajoene interferes with the protein prenylation reaction, an effect that may contribute to its inhibition of SMC proliferation.

Animals↗
PubMed2003

Efficacy and safety of plant stanols and sterols in the management of blood cholesterol levels.

Foods with plant stanol or sterol esters lower serum cholesterol levels. We summarize the deliberations of 32 experts on the efficacy and safety of sterols and stanols. A meta-analysis of 41 trials showed that intake of 2 g/d of stanols or sterols reduced low-density lipoprotein (LDL) by 10%; higher intakes added little. Efficacy is similar for sterols and stanols, but the food form may substantially affect LDL reduction. Effects are additive with diet or drug interventions: eating foods low in saturated fat and cholesterol and high in stanols or sterols can reduce LDL by 20%; adding sterols or stanols to statin medication is more effective than doubling the statin dose. A meta-analysis of 10 to 15 trials per vitamin showed that plasma levels of vitamins A and D are not affected by stanols or sterols. Alpha carotene, lycopene, and vitamin E levels remained stable relative to their carrier molecule, LDL. Beta carotene levels declined, but adverse health outcomes were not expected. Sterol-enriched foods increased plasma sterol levels, and workshop participants discussed whether this would increase risk, in view of the marked increase of atherosclerosis in patients with homozygous phytosterolemia. This risk is believed to be largely hypothetical, and any increase due to the small increase in plasma plant sterols may be more than offset by the decrease in plasma LDL. There are insufficient data to suggest that plant stanols or sterols either prevent or promote colon carcinogenesis. Safety of sterols and stanols is being monitored by follow-up of samples from the general population; however, the power of such studies to pick up infrequent increases in common diseases, if any exist, is limited. A trial with clinical outcomes probably would not answer remaining questions about infrequent adverse effects. Trials with surrogate end points such as intima-media thickness might corroborate the expected efficacy in reducing atherosclerosis. However, present evidence is sufficient to promote use of sterols and stanols for lowering LDL cholesterol levels in persons at increased risk for coronary heart disease.

Animals↗
PubMed2002

Polymorphonuclear leukocyte-myocyte interaction: an early event in collar-induced rabbit carotid intimal thickening.

The importance of mononuclear leukocyte (MO) adhesion to dysfunctional endothelium and migration to the subendothelial space in the early phases of atherogenesis is well established. Few studies have addressed the relevance of polymorphonuclear leukocytes (PMNs) in the context of evolving lesions, and nothing is known about PMN interaction with vascular smooth muscle cells (SMCs). In this study, we investigated leukocyte/SMC interactions in a model of rabbit carotid injury induced by placement of a silastic collar. This procedure leads to the development of intimal thickening characterized by SMC accumulation preceded by an abundant leukocyte infiltration. By transmission electron microscopy and immunocytochemistry, we demonstrated the occurrence of PMN infiltration starting at 6 h and ceasing within 72 h after collar placement. A previously unknown extensive interaction between medial myocytes and PMNs was detected, referring to emperipolesis, an active phenomenon of cells engulfing other cells in a process other than phagocytosis. PMNs, but not MOs, were internalized by SMCs, which showed ultrastructural features intermediate between the true contractile and the fully synthetic phenotype without exhibiting any sign of injury. Emperipolesis preceded any detectable cell proliferation in the vessel wall and disappeared within 72 h, following the kinetic of PMN infiltration in the vessel wall. In summary, our findings show the occurrence of an active and selective interaction between PMNs and SMCs via emperipolesis during the early phases of intimal thickening after perivascular collaring. However, the overall etiology of the phenomena described in the present study and their pathophysiological significance should be further investigated.

Animals↗
PubMed2002

Smoking and gender.

Smoking is a major cause of coronary heart disease for both men and women and a positive correlation between tobacco use and cerebrovascular disease has been also described. In addition, cigarette smoking is the most powerful risk factor predisposing to atherosclerotic peripheral artery disease. More recently, passive smoking has been also shown to represent an important risk factor for coronary artery disease. Moreover, the incidence of coronary artery and cerebrovascular diseases in ex-smokers consistently decreases after cessation, further underlying the relevance of smoking as a risk factor for these pathological conditions. The effects of cigarette smoking on atherosclerosis initiation and progression as well on its complications are mostly responsible for the enhanced cardio- and cerebrovascular risk observed in smoking compared to non-smoking subjects. Since hormonal status may also play a role in the development and stability of the atherosclerotic plaque, smoking habits could influence the clinical complications of atheroclerosis in a gender dependent manner. Up to now, however, few studies have investigated the relative importance of smoking as a risk factor for fatal and non-fatal diseases in the two sexes within the same study population. On the basis of available clinical data, this review will discuss the risk of fatal and non-fatal diseases among smoking men and women with special emphasis on cardiovascular and cerebrovascular disease which also represents the most common cause of death among smokers. A description of the mechanisms involved in the tobacco-induced atherosclerotic damage will be also given in order to underline possible gender-related differences.

Adrenergic beta-Antagonists↗
PubMed2002

Pharmacological interactions of statins.

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are effective in reducing the risk of coronary events, and are generally very well tolerated. However, simvastatin, lovastatin, cerivastatin and atorvastatin are biotransformed in the liver primarily by cytochrome P450 (CYP) 3A4, and clinical experience has shown that the risk of adverse effect, such as myopathy, increases with concomitant use of statins with drugs that substantially inhibit CYP 3A4 at therapeutic doses. Indeed, pharmacokinetic interactions (e.g. increased bioavailability), myositis, and rhabdomyolysis have been reported following concurrent use of atorvastatin, cerivastatin, simvastatin or lovastatin and cyclosporine A, mibefradil or nefazodone. In contrast, fluvastatin (mainly metabolized by CYP 2C9) and pravastatin (eliminated by other metabolic routes) are less subject to this interaction. Nevertheless, an increase in pravastatin bioavailability has been reported in the presence of cyclosporine A, possibly because of an interaction at the level of biliary excretion. In summary, some statins may have lower adverse drug interaction potential than others, which is an important determinant of safety during long-term therapy.

Atorvastatin↗
PubMed2002

Novel statins: pharmacological and clinical results.

Rosuvastatin (ZD4522) and pitavastatin (NK-104) are novel HMG-CoA reductase inhibitors with a peculiar pharmacological profile. In particular, they show a high potency in decreasing LDL-C and their catabolism is not mediated by the cytochrome P-450 3A4, thus reducing the potential for drug-drug interaction and improving the management of blood cholesterol. As the magnitude of LDL-C reduction is directly associated with the decrease in the incidence of myocardial infarction and mortality for CAD, statins with increased LDL-C lowering potency may ensure the achievement of target LDL-C levels and offer a more aggressive cholesterol control, further improving CAD morbidity and mortality.

Animals↗
PubMed2002

Safety considerations for statins.

PURPOSE OF REVIEW: The hydroxymethyl glutaryl coenzyme A reductase inhibitors or statins offer important benefits for the large populations of individuals at high risk for coronary heart disease. These drugs have a good safety profile. Nevertheless, differences in physicochemical and pharmacokinetic properties between statins may translate into significant differences in long-term safety. This review focuses on long-term adverse effects related to statin use, namely hepatotoxicity and myopathy. Moreover, the most common drugs used in combination with statins in long-term therapies are analyzed in terms of possible drug/drug interactions affecting the safety of statins. RECENT FINDINGS: The withdrawal of cerivastatin from the global market in 2001, because of severe cases of rhabdomyolysis, highlighted concerns regarding the safety of the entire class. Afterwards, the role of statins and their interactions with other drugs in precipitating this condition have been carefully reviewed. In approximately 60% of the total number of cases, statin-related rhabdomyolysis was found to be related to drug/drug interactions. Recently, all cases of fatal rhabdomyolysis associated with statin use have been reported to the US Food and Drug Administration. This has shown that fatal rhabdomyolysis among statin users is a rare event, the reporting rates being much less than one death per million prescriptions in the case of all statins except cerivastatin. SUMMARY: The safety and tolerability of the available statins support their use as the first-line treatment of patients at high risk for coronary heart disease, since the clinical benefits greatly outweigh the small risk of myopathy. Nevertheless, clinicians should be aware of the adverse effects possibly related to statin therapy, particularly in patients at high risk for coronary heart disease and requiring long-term multiple-drug therapies.

Anticholesteremic Agents↗
PubMed2002

New insights into brain damage in stroke-prone rats: a nuclear magnetic imaging study.

BACKGROUND AND PURPOSE: The spontaneously hypertensive stroke-prone rat (SHRSP) is an animal model for a complex form of cerebrovascular pathology. MRI provides an efficient and noninvasive tool for studying the time course of brain damage. The aim of this study was to gain new insights into the pathological phenomena responsible for the occurrence of brain injury in SHRSP with the use of the apparent diffusion coefficient of water (ADC), one of the most efficient MRI parameters for detecting brain abnormalities. To this end, the pattern of ADC variation observed in SHRSP was compared with that of focal ischemia induced in both SHRSP and Sprague-Dawley rats. METHODS: Four groups of animals were studied: SHRSP developing spontaneous brain lesions fed with a salt-loaded (n=15, group 1) or standard diet (n=3, group 2) and Sprague-Dawley rats (n=8, group 3) and SHRSP (n=8, group 4) with permanent middle cerebral artery occlusion. ADC maps and T2-weighted images of brains were performed by MRI. After the rats were killed, the brains were removed and histologically processed. RESULTS: There was no decrease in ADC during spontaneous stroke in the SHRSP fed with a normal or salt-enriched diet, while both the SHRSP and Sprague-Dawley rats with middle cerebral artery occlusion showed a marked decrease that lasted for 24 to 48 hours. CONCLUSIONS: Cerebral ischemia cannot be considered a major factor in the onset of spontaneous brain lesions in SHRSP, which show only vasogenic edema after the beginning of the damage with no evidence of metabolic impairment.

Animals↗
PubMed2002

Cholesterol-induced thrombogenicity of the vessel wall: inhibitory effect of fluvastatin.

High cholesterol levels are a known risk factor for coronary events. The molecular links between high serum cholesterol and the increased thrombogenicity of the arterial wall are still matter of investigation. In the present study we investigate the relationship between plasma cholesterol, thrombus formation and TF expression in a atherosclerotic rabbit model. Hypercholesterolemic rabbits showed a pronounced TF staining as well as NF-kappaB activation in the aortic arch. A consistent vessel wall platelet deposition was also observed. Treatment with fluvastatin reduced lipid accumulation, TF overexpression (-60%), NF-kappaB activation, and platelet deposition (-56%). In vitro studies showed that the drug upregulated IkappaB alpha in unstimulated as well as in TNFalpha-stimulated cells and also impaired the TNFalpha-induced Cdc42 prenylation, indicating that fluvastatin interferes with the transcriptional activation of TF gene. These results indicate that the prothrombotic phenotype of arterial wall, associated with elevated serum cholesterol levels, is mediated by TF overexpression. Fluvastatin treatment reduces the prothrombotic tendency by inhibiting TF synthesis.

Animals↗