Role of the Benzodioxole Group in the Interactions between the Natural Alkaloids Chelerythrine and Coptisine and the Human Telomeric G-Quadruplex DNA. A Multiapproach Investigation.

The binding properties toward the human telomeric G-quadruplex of the two natural alkaloids coptisine and chelerythrine were studied using spectroscopic techniques, molecular modeling, and X-ray diffraction analysis. The results were compared with reported data for the parent compounds berberine and sanguinarine. Spectroscopic studies showed modest, but different rearrangements of the DNA-ligand complexes, which can be explained considering particular stereochemical features for these alkaloids, in spite of the similarity of their skeletons. In fact, the presence of a dioxolo moiety rather than the two methoxy functions improves the efficiency of coptisine and sanguinarine in comparison to berberine and chelerythrine, and the overall stability trend is sanguinarine > chelerythrine ≈ coptisine > berberine. Accordingly, the X-ray diffraction analysis confirmed the involvement of the benzodioxolo groups in the coptisine/DNA binding by means of π···π, O···π, and CH···O interactions. Similar information is provided by modeling studies, which, additionally, evidenced reasons for the quadruplex vs double-helix selectivity shown by these alkaloids. Thus, the analyses shed light on the key role of the benzodioxolo moieties in strengthening the interaction with the G4-folded human telomeric sequence and indicated the superior G4 stabilizing properties of the benzophenanthridine scaffold with respect to the protoberberine one and conversely the better G4 vs dsDNA selectivity profile of coptisine over the other alkaloids.

[Therapy of dyslipidemia in post-infarction: state of the art]. / Terapia delle dislipidemie nel post-infarto: stato dell'arte.

Between the risks factors involved in the atherogenesis LDL-cholesterol is determinant because highly associated to cardiovascular events. The primary target for the prevention of coronary diseases is a reduction of LDL-cholesterol because that reduces the cardiovascular mortality and the total mortality. The NCEP ATP III 2004 guide-lines propose as therapeutic target for the high-risk patients the reduction of plasma levels of LDL-cholesterol under 100 mg/dl and according to new trials under 70 mg/dl. The dyslipidaemia treatments are based on two approaches, i.e., the therapeutic lifestyle change and the pharmacological therapy. The available drugs are statins, fibrates, anion exchange resins, nicotinic acid. In the acute coronary syndrome patients is desirable to start immediately a therapy with statins since the hospital phase and direct the treatment to aggressive therapy. Unfortunately, the statin doses used in the most secondary prevention trials allow to get LDL-cholesterol under 100 mg/dl in the only half high-risk patients. The innovative therapeutic approach to hypercholesterolemia today is based on a double inhibition of cholesterol synthesis and absorption combining a statin with ezetimibe.

Effect of blood pressure and physical activity on carotid artery intima-media thickness in stage 1 hypertensives and controls.

The aim of the study was to investigate whether hypertension and physical training induce parallel changes in the arterial wall. Ninety-seven never-treated stage 1 hypertensive patients (HT) (systolic blood pressure 140 to 159 mm Hg or diastolic blood pressure 90 to 99 mm Hg) aged 18 to 45 years taking part in the Hypertension and Ambulatory Recording Venetia Study and 27 normotensive volunteers (NT) aged 30 +/- 9 years were studied. Data on physical or sports activity were collected and scored, and target organ involvement was investigated by assessing microalbuminuria, echocardiography, and carotid ultrasound study. The carotid arteries were examined according to the Atherosclerosis Risk in Communities protocol. Mean (m-IMT) and maximal (M-IMT) carotid intima-media thickness were measured at end-diastole in the far wall common carotid artery, in the bulb and internal carotid artery, in the lateral and posterior projection, averaging the left and right sides. A comparable level of physical activity was present in HT patients and NT subjects. Twenty-four-hour blood pressure and blood lipid levels, as well as target organ damage, were similar in physically active and sedentary HT. The m-IMT of the common carotid was greater in sedentary HT than in sedentary NT, as well as in active than in sedentary NT. The m-IMT of the internal carotid artery was also greater in active HT than in active NT, as well as in active than in sedentary HT. In logistic regression, comparing the first and fourth quartile of m-IMT, scored physical activity was a predictor of m-IMT in the internal carotid artery. No statistical interaction was found between physical activity and hypertension, indicating that these two items have a cumulative effect and act independently of each other. Sedentary HT had significantly greater levels of M-IMT than sedentary NT in all sites but the bulbs; in the internal and common carotid arteries, HT exercisers had significantly greater M-IMT than NT exercisers. Therefore, physical activity appears to be an early independent predictor of carotid wall thickness. This factor should be taken into consideration in population-based studies aimed at investigating supraortic vessels as it can act as a confounder.

Factors underlying the increase in carotid intima-media thickness in borderline hypertensives.

To define the role played by various risk and behavioral factors in the increase of carotid intima-media thickness (IMT) observed in borderline hypertensives. Using B-mode ultrasonography, we compared 97 borderline hypertensives enrolled in the HARVEST study to 27 normotensive controls. Intima-media thickness was measured in the right and left common carotid artery, bulb, and internal carotid artery. Mean IMT (m-IMT), maximum IMT (M-IMT), the mean of M-IMT (M-MAX), and the prevalence of raised lesions (IMT>1 mm) were established. Compared to the controls, higher systolic BP, diastolic BP, mean arterial blood pressure levels and body mass index (BMI) were present in the borderline hypertensives, whereas age, smoking, physical activity, serum cholesterol, and triglycerides were similar. After adjusting for age, sex, heart rate, BMI, smoking, serum cholesterol, triglycerides, and physical activity, higher values of m-IMT and M-IMT were present in most carotid segments of borderline hypertensives compared with controls. After further adjustment for systolic BP and diastolic BP, differences were no longer significant. The adjusted M-MAX was 0.59+/-0.12 in borderline hypertensives compared with 0.50+/-0.10 in controls (P<0.001). After adjustment for systolic BP and diastolic BP it was 0.58+/-0.11 in borderline hypertensives compared with 0.50+/-0.12 in controls (P<0.005). In the various carotid segments, the prevalence of raised lesions was 1. 2% in borderline hypertensives compared with 0.3% in controls (P<0. 001). In the multivariate analysis m-IMT, M-IMT, and M-MAX were related to ambulatory mean arterial pressure, systolic BP and diastolic BP, serum cholesterol and triglycerides, BMI, age, and physical activity. Higher IMT values were found in subjects who were physically active than in those who were sedentary. In borderline hypertensives, an increase in IMT takes place not only in the common carotid artery but also in the bulb and the internal carotid segment. Blood pressure levels are a main determinant of m-IMT while the interaction of BP with other risk factors such as age and plasma lipids is more relevant for advanced intima-media thickening such as M-MAX.

Anipamil prevents intimal thickening in the aorta of hypertensive rabbits through changes in smooth muscle cell phenotype.

The aim of this study was to evaluate the effect of anipamil, a phenyalkylamine-derived Ca(2+)-antagonist, on aortic intimal thickening and smooth muscle cell (SMC) phenotype in 2K-1C hypertensive rabbits. Monoclonal antimyosin antibodies [SM-E7, NM-G2, and NM-F6, which respectively, recognize smooth muscle (SM), A-type-, and B-type-like nonmuscle (NM) myosin heavy chains (MyHC)] identify different aortic SMC types: adult (SM-E7-positive), postnatal (SM-E7- and NM-G2-positive), and fetal (SM-E7-, NM-G2-, and NM-F6-positive). Twenty-four hypertensive rabbits were studied 2.5 months (n = 12) and 4 months (n = 12) after clipping. Six animals from each group were given anipamil (40 mg orally, once daily) immediately after surgery. The remaining 2K-1C were given a daily oral placebo. Normotensive age-matched controls were also studied. Transverse cryosections of aorta were taken for computerized morphometry and immunocytochemical studies. Primary and secondary SMC cultures were used to define potential changes in cell phenotype after adding anipamil to the culture medium. In untreated 2K-1C, intimal thickening, mainly composed of postnatal-type SMC, was found by 2.5 months after clipping. Morphometric and immunofluorescence studies in anipamil-treated 2K-1C rabbits revealed absent or negligible intimal thickening and a decrease of postnatal-type SMC from the underlying media. In culture experiments, growth inhibition of SMC by anipamil was accompanied by the expression of SM-MyHC in all SMC, ie, the appearance of a more differentiated cell phenotype compared to control cultures. In conclusion, prevention of intimal thickening in anipamil-treated 2K-1C was achieved through selective reduction in the media of the postnatal-type SMC. This could be achieved by reducing NM-MyHC content or increasing synthesis of SM-MyHC expression. As blood pressure was not significantly lowered by anipamil treatment, a direct and specific antiproliferative action of this drug on medial SMC is likely to take place.

Antiatherogenic action of nitrendipine in hypercholesterolemic rabbits: changes in aortic macrophage accumulation and smooth muscle cell phenotype.

Intimal accumulation of macrophages and changes in the phenotype and growth properties of vascular smooth muscle cells (SMCs) represent key events in the development of atherosclerotic lesions. Here we report on the in vivo effect exerted by nitrendipine on aortic tissue of cholesterol-fed rabbits. We have focused especially on the myosin heavy chain (MyHC) pattern expressed by aortic SMC, taken as a marker of cell differentiation. Using monoclonal antibodies specific to the different forms of MyHC, three differentiation steps were determined: adult, postnatal, and fetal. Nitrendipine administered in conjunction with a cholesterol-enriched diet reduced the development of atherosclerotic lesions (atherosclerosis index: 0.21 vs. 0.32 in untreated animals, p< 0.005), despite persistently high serum cholesterol levels. Compared to untreated controls, nitrendipine-treated animals displayed a decreased number of postnatal-type SMCs in the media underlying the plaque (prevalence index: 0.07 vs. 0.26, p < 0.0001 and a lower aortic cholesterol content (free cholesterol: 3.3 vs. 11.5 ng/mg, p< 0.0001; esterified cholesterol: 7.2 vs. 40.5 ng/mg, p< 0.0001). Moreover, nitrendipine treatment decreased the intimal accumulation of macrophages and fetal-type SMCs. It is conceivable that calcium antagonists may exert their antiatherogenic effect, at least in part, through cellular changes unrelated to the classical risk factors.

Smooth muscle cell types at different aortic levels and in microvasculature of rabbits with renovascular hypertension.

BACKGROUND: The monoclonal antimyosin antibodies smooth muscle (SM)-E7, non-muscle (NM)-G2 and NM-F6 recognize smooth muscle myosin heavy chains, and A- and B-like non-muscle myosin heavy chains, respectively. On this basis, aortic smooth muscle cell types have been identified as adult (SM-E7-positive), postnatal (SM-E7- and NM-G2-positive) and fetal (SM-E7-, NM-G2- and NM-F6-positive). We have demonstrated previously that hypertrophy of the smooth muscle cell layer of the upper aorta in two-kidney, one clip hypertensive rabbits is achieved via a selective increase in postnatal-type smooth muscle cells. OBJECTIVE: To monitor the time-course change of postnatal-type smooth muscle cells along the entire aortic tree and to define the phenotypic characteristics of the microvasculature in the same rabbit model. MATERIALS AND METHODS: Hypertensive rabbits were killed 0.5, 1, 2.5, 4, 6 and 8 months after clipping. Normotensive age-matched rabbits served as controls. The entire aorta was frozen during perfusion at a constant pressure for morphometric and immunocytochemical studies. Transverse cryosections were taken 1 cm from the aortic valve (level A), immediately after the anonymous trunk (level B), immediately before the diaphragm (level C), and near the bifurcation (level D). Small vessels and arterioles were studied in psoas skeletal muscle and in left ventricular myocardium. RESULTS: On the whole, aortae from hypertensive rabbits displayed a striking increase in postnatal-type smooth muscle cells at all levels by 4 months of hypertension and a progressive decrease in the number of these cells to near the control value by 8 months of hypertension. A peculiar pattern of myosin heavy chain expression was found in the microvasculature. In control and in hypertensive rabbits, both at 4 and at 8 months, small vessels and arterioles were equally reactive with the three antimyosin heavy chain antibodies. This indicates a basic prevalence of fetal-type smooth muscle cells, which is little influenced by blood pressure. CONCLUSIONS: The present data elucidate some of the basic changes which the entire aortic segment and microvasculature undergo in the present experimental model.

Impact of nifedipine on vascular smooth muscle cell differentiation. Implications for atherogenesis.

Although vascular smooth muscle cells (SMCs) play a key role in the development of atherosclerotic lesions, they are not a homogeneous cell type. Myosin has been used as a marker of SMC differentiation in order to identify distinct SMC populations in the adult rabbit aorta. The medial layer of the normal adult aorta contains predominantly 'adult' type SMCs, which express smooth muscle (SM) myosin isoforms exclusively, and a minority of 'immature' type SMCs, which coexpress SM and nonmuscle (NM) myosin isoforms. The size of this latter SMC subpopulation, showing the 'immature' pattern of myosin isoform expression, increases markedly in the aortic media during experimental atherogenesis, and represents a major SMC type in the atherosclerotic plaque. The dihydropyridine derivative, nifedipine, has a marked effect on NM myosin expression and SMC differentiation in vitro. In vivo, short term administration of nifedipine resulted in the disappearance of 'immature' type SMCs from the aortic media of both normocholesterolaemic and hypercholesterolaemic adult rabbits. Moreover, in a model of atherosclerosis prevention, nifedipine significantly reduced the area of aortic intimal thickening and reduced the size of the 'immature' type SMC population both in the aortic media and intima of the hypercholesterolaemic rabbit.