Predictive role of renal resistive index for clinical outcome after revascularization in hypertensive patients with atherosclerotic renal artery stenosis: a monocentric observational study.

BACKGROUND: The present study evaluated the predictive value of renal resistive index (RI) for renal function and blood pressure (BP) outcome in hypertensive patients with unilateral atherosclerotic renal artery stenosis submitted to successful revascularization. METHODS: In 158 hypertensive patients with atherosclerotic renal artery stenosis RI was acquired. Twelve months after revascularization, they were classified on the basis of renal function and BP outcome as benefit (BP < 140/90 mmHg or diastolic BP reduction > 15 mmHg with the same of reduced drugs; decrease in glomerular filtration rate > 20%), or failure. RESULTS: Regarding renal function outcome, RI in the stenotic and in the contralateral kidney were significantly higher in patients with failure (n = 20) than in those with benefit (0.72 ± 0.11 vs 0.61 ± 0.11 and 0.76 ± 0.08 vs 0.66 ± 0.09, p < 0.05). Among different cutpoints generated, RI in the contralateral kidney >0.73 provided the largest area under the curve (0.77), and the highest sensitivity (80%) and specificity (72%). In the multivariate logistic regression analysis, RI in the contralateral kidney >0.73 was an independent predictor of a failure in renal function outcome.Regarding BP outcome, patients with no benefit from revascularization (n = 60) had similar RI in the stenotic and contralateral kidney (p = ns), but presented higher pulse pressure, albuminuria and hypertension duration in comparison to patients with improved BP control. CONCLUSIONS: RI in the contralateral kidney is an independent predictor of renal function outcome after successful revascularization in hypertensive patients with unilateral atherosclerotic renal artery stenosis, whereas it is not able to predict blood pressure outcome.

Segmental heterogeneity of vasa vasorum neovascularization in human coronary atherosclerosis.

OBJECTIVES: Our aim was to investigate the role of coronary vasa vasorum (VV) neovascularization in the progression and complications of human coronary atherosclerotic plaques. BACKGROUND: Accumulating evidence supports an important role of VV neovascularization in atherogenesis and lesion location determination in coronary artery disease. VV neovascularization can lead to intraplaque hemorrhage, which has been identified as a promoter of plaque progression and complications like plaque rupture. We hypothesized that distinctive patterns of VV neovascularization and associated plaque complications can be found in different stages of human coronary atherosclerosis. METHODS: Hearts from 15 patients (age 52+/-5 years, mean+/-SEM) were obtained at autopsy, perfused with Microfil (Flow Tech, Inc., Carver, Massachusetts), and subsequently scanned with micro-computed tomography (CT). The 2-cm segments (n=50) were histologically classified as either normal (n=12), nonstenotic plaque (<50% stenosis, n=18), calcified (n=10) or noncalcified (n=10) stenotic plaque. Micro-CT images were analyzed for VV density (number/mm2), VV vascular area fraction (mm2/mm2), and VV endothelial surface fraction (mm2/mm3). Histological sections were stained for Mallory's (iron), von Kossa (calcium), and glycophorin-A (erythrocyte fragments) as well as endothelial nitric oxide synthase, vascular endothelial growth factor, and tumor necrosis factor-alpha. RESULTS: VV density was higher in segments with nonstenotic and noncalcified stenotic plaques as compared with normal segments (3.36+/-0.45, 3.72+/-1.03 vs. 1.16+/-0.21, p<0.01). In calcified stenotic plaques, VV spatial density was lowest (0.95+/-0.21, p<0.05 vs. nonstenotic and noncalcified stenotic plaque). The amount of iron and glycophorin A was significantly higher in nonstenotic and stenotic plaques as compared with normal segments, and correlated with VV density (Kendall-Tau correlation coefficient 0.65 and 0.58, respectively, p<0.01). Moreover, relatively high amounts of iron and glycophorin A were found in calcified plaques. Further immunohistochemical characterization of VV revealed positive staining for endothelial nitric oxide synthase and tumor necrosis factor-alpha but not vascular endothelial growth factor. CONCLUSIONS: Our results support a possible role of VV neovascularization, VV rupture, and intraplaque hemorrhage in the progression and complications of human coronary atherosclerosis.

Expression of lipoprotein-associated phospholipase A(2) in carotid artery plaques predicts long-term cardiac outcome.

AIMS: The aim was to test the hypothesis that carotid artery plaque expression of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) predicts cardiac events. METHODS AND RESULTS: Prospective cohort study of 162 consecutive patients undergoing elective carotid endarterectomy. Lipoprotein-associated phospholipase A(2) content was quantified by immunoblotting and lysophosphatidylcholine (lysoPC) by liquid chromatography tandem mass spectrometry. Additional biomolecular profiling by immunoblotting included C-reactive protein, p67phox, and matrix metalloproteinase-2 and -9. Macrophage plaque content was determined by quantitative immunostaining, plaque collagen content by quantitative Sirius red staining. Follow-up for cardiac death and non-fatal acute myocardial infarction was accomplished over a period of 48 +/- 14 months. Expression of Lp-PLA(2) and lysoPC was higher in carotid plaques of patients with than without cardiac events [median 1.6 (25th, 75th percentile 0.9, 2.5) vs. 0.8 (0.5, 2.0), P = 0.01 and 413 (281, 443) vs. 226 (96, 351) mmol/L, P = 0.03]. Smoking and point increase in carotid Lp-PLA(2) expression but no other traditional cardiovascular risk factor, histological or molecular marker remained predictive of cardiac events in the multivariate Cox proportional hazard analyses [HR 3.65 (1.36-9.83), P = 0.01 and HR 1.34 (1.01-1.77), P = 0.039]. Carotid plaque Lp-PLA(2) expression above the median constituted a more than three times higher risk for cardiac events [HR 3.39 (1.13-10.17), P = 0.03]. CONCLUSION: Lipoprotein-associated phospholipase A(2) expression in carotid artery plaques is a predictor of long-term cardiac outcome. The current study supports the concept of atherosclerosis as a systemic disease with multi-focal complications and personalized medicine.

Lack of pharmacokinetic bioequivalence between generic and branded amoxicillin formulations. A post-marketing clinical study on healthy volunteers.

AIMS: There are concerns about the quality of generic drugs in the postmarketing setting. The aim was to establish whether two generic formulations of amoxicillin, available on the Italian market, fulfil the criteria for clinical pharmacokinetic bioequivalence vs. the branded drug. METHODS: Two generic amoxicillin products (generic A and B) were selected among four fast-release tablet formulations available on the Italian market. Twenty-four healthy adult volunteers of either sex participated to a single-dose, randomized, three-treatment, crossover, single-blind bioequivalence study designed to compare generic A and B with branded amoxicillin. Plasma samples were collected at preset times for 24 h after dosing, and assayed for amoxicillin levels by high-performance liquid chromatography. RESULTS: Ninety percent confidence intervals of AUC ratios were 0.8238, 1.0502 (ratio 0.9302) and 0.8116, 1.1007 (ratio 0.9452) for generic A and B vs. branded amoxicillin, respectively. Ninety percent confidence intervals of C(max) ratios were 0.7921, 1.0134 (ratio 0.8960) and 0.8246, 1.1199 (ratio 0.9610) for generic A and B vs. branded amoxicillin, respectively. The mean pharmacokinetic profiles showed that the AUC value of branded amoxicillin was 8.5 and 5.4% greater than that estimated for generic A and B, respectively. Few adverse events were recorded; these were not serious and occurred without apparent relationship to any specific amoxicillin formulation. CONCLUSIONS: These results indicate that one of the two marketed amoxicillin generics analysed in the present study is not bioequivalent to the brand leader product for C(max) on the basis of single-dose pharmacokinetic assessment.

Endothelium-dependent contractions and endothelial dysfunction in human hypertension.

The endothelium is a crucial regulator of vascular physiology, producing in healthy conditions several substances with a potent antiatherosclerotic properties. Accordingly, the presence of endothelial dysfunction is associated with subclinical atherosclerosis and with an increased future risk of cardiovascular events. A large body of evidence supports the fundamental role of nitric oxide (NO) as the main endothelium-derived relaxing factor. However, in the presence of pathological conditions, such as hypertension, endothelial cells, in response to a number of agents and physical stimuli, become also a source of endothelium-derived contracting factors (EDCFs), including endothelins and angiotensin II and particularly cyclooxygenase-derived prostanoids and superoxide anions. These latter were at first identified as responsible for impaired endothelium-dependent vasodilation in patients with essential hypertension. However, cyclooxygenase-dependent EDCFs production is characteristic of the aging process, and essential hypertension seems to only anticipate the phenomenon. It is worth noting that both in aging and hypertension EDCF production is associated with a parallel decrease in NO availability, suggesting that this substance could be oxygen free radicals themselves. Accordingly, in hypertension both indomethacin, a cyclooxygenase inhibitor, and vitamin C, an antioxidant, increase the vasodilation to acetylcholine by restoring NO availability. In conclusion, hypertension is characterized by a decline in endothelial function, associated with a progressive decrease in NO bioavailability and increase in the production of EDCF. The mechanisms that regulate the balance between NO and EDCF, and the processes transforming the endothelium from a protective organ to a source of vasoconstrictor, proaggregatory and promitogenic mediators remain to be determined.

Myocardial microvascular function during acute coronary artery stenosis: effect of hypertension and hypercholesterolaemia.

AIMS: Coronary collateral arteries (CCA) reduce cardiovascular events. We tested the hypothesis that new microvessels that proliferate in early atherosclerosis may be associated with myocardial protection during acute subtotal coronary artery obstruction (CAO). METHODS AND RESULTS: Acute left anterior descending CAO was induced by a balloon catheter in pigs after 12 weeks of high-cholesterol (HC) diet, renovascular hypertension (HTN), or normal control. Cardiac structure, myocardial perfusion, and functional response to iv adenosine and CAO were studied in vivo using electron beam computed tomography (CT). The intra-myocardial microvessels were subsequently evaluated ex vivo using micro-CT, and myocardial expression of growth factors using immunoblotting. Basal myocardial perfusion and microvascular permeability were similar among the groups, whereas their responses to adenosine were attenuated in HC and HTN. A significant decline in myocardial perfusion in normal pigs during acute CAO was attenuated in HC and abolished in HTN. CAO also elicited an increase in normal anterior wall microvascular permeability (+202 +/- 59%, P < 0.05), which was attenuated in HC and HTN (+55 +/- 9 and +31 +/- 8%, respectively, P < 0.05 vs. normal). Microvascular (<200 microm) spatial density was significantly elevated in HC and HTN, accompanied by increased myocardial growth factor expression. CONCLUSION: This study demonstrates that early exposure to the cardiovascular risk factors HC and HTN protects the heart from decreases in myocardial perfusion during acute subtotal CAO. This protective effect is associated with and potentially mediated by pre-emptive development of intra-myocardial microvessels that might serve as recruitable CCA.

Prevention of vasa vasorum neovascularization attenuates early neointima formation in experimental hypercholesterolemia.

Vasa vasorum (VV) neovascularization is a key feature of early atherosclerosis and adds substantial endothelial exchange-surface to the coronary vessel wall. Thus, it is conceivable that VV neovascularization favors the entry of pro-inflammatory and pro-atherosclerotic blood components into the coronary vessel wall. We sought to investigate the effects of Thalidomide (Th), a potent anti-angiogenic drug on vasa vasorum (VV) neovascularization, vessel wall inflammation, and neointima formation in early experimental atherosclerosis. Female domestic swine, 3 months old, were fed normal (N, n = 12) or high-cholesterol diet (HC, n = 12) for 3 months. In each group six pigs were randomized to 200 mg Thalidomide daily for the diet period (N + Th, HC + Th). LADs were scanned with micro-CT (20 microm cubic voxel size) to determine VV spatial density (#/mm2). Fresh-frozen coronary tissue was used for western blotting (VEGF, TNF-alpha, LOX-1, Ikappabetaalpha and Gro-alpha) and electrophoretic mobility shift assay (EMSA, NFkappabeta). Treatment with Thalidomide preserved VV spatial density [2.7 +/- 0.3 (N), 6.4 +/- 0.7 (HC), 3.5 +/- 0.8 (HC + Th); p = ns HC + Th vs. N] and inhibited the expression of VEGF, TNF-alpha and LOX-1, but not NFkappabeta activity in the coronary vessel wall. Immunofluorescence analyses revealed co-localization of vWF but not SMA and NFkappabeta, TNF-alpha as well as VEGF in HC and HC + Th coronaries. Intima-media thickness was significantly inhibited in HC + Th compared to HC. Serum levels of hs-CRP and TNF-alpha did not differ among the groups. Our study supports a role of VV neovascularization in the development of and a therapeutic potential for anti-angiogenic intervention in early atherosclerosis.

Atorvastatin prevents endothelial dysfunction in mesenteric arteries from spontaneously hypertensive rats: role of cyclooxygenase 2-derived contracting prostanoids.

We investigated the effect of atorvastatin on cyclooxygenase (COX) contribution to endothelial dysfunction in spontaneously hypertensive rat (SHR) mesenteric resistance arteries. Atorvastatin (10 mg/kg per day, oral gavage) or its vehicle was administered for 2 weeks to male SHR or Wistar-Kyoto rats. Endothelial function of mesenteric arteries was assessed by pressurized myograph. In Wistar-Kyoto rats, relaxation to acetylcholine was inhibited by N(G)-nitro-L-arginine methyl ester and unaffected by SC-560 (COX-1 inhibitor), DuP-697 (COX-2 inhibitor), or ascorbic acid. In SHRs, the response to acetylcholine was attenuated, less sensitive to N(G)-nitro-L-arginine methyl ester, unaffected by SC-560, and enhanced by DuP-697 or SQ-29548 (thromboxane-prostanoid receptor antagonist) to a similar extent. Endothelium-dependent relaxation was normalized by ascorbic acid or apocynin (NADPH oxidase inhibitor), which also restored the inhibition by N(G)-nitro-L-arginine methyl ester. In atorvastatin-treated SHRs, relaxation to acetylcholine was normalized, fully sensitive to N(G)-nitro-L-arginine methyl ester, and not affected by SC-560, DuP-697, SQ 29548, or antioxidants. Dihydroethidium assay showed an increased intravascular superoxide generation in SHRs, which was abrogated by atorvastatin. RT-PCR revealed a COX-2 induction in SHR arteries, which was downregulated by atorvastatin. The release of prostacyclin and 8-isoprostane was higher from SHR than Wistar-Kyoto mesenteric vessels. COX-2 inhibition and apocynin decreased 8-isoprostane without affecting prostacyclin levels. Atorvastatin increased phosphorylated extracellular signal-regulated kinase 1/2, pAkt, peNOS(1177), and inducible NO synthase levels in SHR mesenteric vessels and decreased 8-isoprostane release. In conclusion, COX-2-derived 8-isoprostane contributes to endothelial dysfunction in SHR mesenteric arteries. Atorvastatin restores NO availability by increasing phosphorylated extracellular signal-regulated kinase 1/2, pAkt, peNOS(1177), and inducible NO synthase levels and by abrogating vascular NADPH oxidase-driven superoxide production, which also results in a downregulation of COX-2-dependent 8-isoprostane generation.

Inducible nitric oxide synthase is involved in endothelial dysfunction of mesenteric small arteries from hypothyroid rats.

The time-dependent effects of mild hypothyroidism on endothelial function were assessed in rat mesenteric arteries. Male Wistar rats were treated with methimazole (MMI; 0.003%) or placebo up to 16 wk. Endothelial function of mesenteric small arteries was assessed by pressurized myograph. MMI-treated animals displayed a decrease in serum thyroid hormones, an increment of plasma TSH and inflammatory cytokines, and a blunted vascular relaxation to acetylcholine, as compared with controls. Endothelial dysfunction resulted from a reduced nitric oxide (NO) availability caused by oxidative excess. Vascular-inducible NO synthase (iNOS) expression was up-regulated. S-methylisothiourea (an iNOS inhibitor) normalized endothelium-dependent relaxations and restored NO availability in arteries from 8-wk MMI-animals and partly ameliorated these alterations in 16-wk MMI rats. Similar results were obtained when MMI-induced hypothyroidism was prevented by T(4) replacement. Among controls, an impaired NO availability, secondary to oxidative excess, occurred at 16 wk, and it was less pronounced than in age-matched MMI animals. Both endothelial dysfunction and oxidant excess secondary to aging were prevented by apocynin (nicotinamide adenine dinucleotide phosphate oxidase inhibitor). Mesenteric superoxide production was reduced by S-methylisothiourea and T(4) replacement in MMI animals and abolished by apocynin in controls (dihydroethidium staining). MMI-induced mild hypothyroidism is associated with endothelial dysfunction caused by a reduced NO availability, secondary to oxidative excess. It is suggested that in this animal model, characterized by TSH elevation and low-grade inflammation, an increased expression and function of iNOS, resulting in superoxide generation, accounts for an impaired NO availability.

The ageing endothelium, cardiovascular risk and disease in man.

Ageing is a major risk factor for cardiovascular disease, not only because there is a process of vascular ageing per se but also because ageing increases the time of exposure to other cardiovascular risk factors. Endothelial dysfunction is now considered an early and important mechanism that predisposes to atherothrombotic damage and thus contributes to the occurrence of cardiovascular events. The normal endothelium exerts a major vascular-protecting role by secreting substances, the most important of which is nitric oxide (NO). In disease conditions (such as the presence of cardiovascular risk factors), activation of endothelial cells can lead to the production and release of contracting factors, which counteract the beneficial effects of NO, and reactive oxygen species (ROS), which cause NO breakdown. Besides the opposite effects on vascular tone, NO and endothelium-derived contracting factors also respectively inhibit and activate several other mechanisms that are involved in the pathogenesis of atherothrombosis. Moreover, endothelial dysfunction is associated with vascular subclinical damage and, importantly, an increasing body of evidence strongly suggests that it might be an independent predictor for the risk of future cardiovascular events. Like the other traditional risk factors, ageing has been demonstrated to be associated with progressive impairment of endothelial function, in both conduit arteries and resistance vessels, mainly because of an increased production of ROS. Therefore, it is conceivable that endothelial dysfunction plays a major role in predisposing to age-related increased cardiovascular risk in the elderly.

Vascular reactivity in patients with undifferentiated connective tissue diseases.

INTRODUCTION: Endothelial dysfunction is an early event in the development of atherosclerotic disease. We investigated endothelial function in the peripheral circulation of patients with undifferentiated connective tissue diseases (UCTDs), in comparison to healthy controls. METHODS: In 15 young UCTD patients (mean age 39 years) with inactive disease and without cardiovascular risk factors and in 15 age-matched controls we evaluated endothelial function in the brachial conduit artery and in the forearm microcirculation. The first district was assessed by flow mediated dilation (FMD) and response to glyceryl trinitrate, and forearm microcirculation by blood flow changes (strain-gauge venous plethysmography) in response to intra-arterial acetylcholine (Ach) and sodium nitroprusside (SNP). Nitric oxide (NO) availability was evaluated by repeating Ach in the presence of intraarterial N(G)-monomethyl-l-arginine (l-NMMA), an NO synthase inhibitor. RESULTS: FMD and response to GTN were similar in UCTD patients and controls. UCTD patients showed a reduced response to Ach (P<0.001) and SNP (P<0.01) as compared to controls. In healthy controls l-NMMA infusion significantly (P<0.001) reduced the vascular response to Ach, while in UCTD patients l-NMMA failed to affect vasodilation to Ach. In UCTD patients, vascular responses were unrelated to clinical manifestations or autoantibody profile. CONCLUSIONS: Young UCTD patients are characterized by reduced endothelium-dependent and -independent vasodilation in the forearm microcirculation, but not in peripheral conduit arteries. Reduced NO availability was indirectly observed. These results suggest that in the absence of traditional risk factors, inactive systemic autoimmune diseases impair NO-dependent but also endothelium-independent vasodilation selectively in the microcirculation.

Anthropometric and dietary determinants of blood pressure in over 7000 Mediterranean women: the European Prospective Investigation into Cancer and Nutrition-Florence cohort.

BACKGROUND: Anthropometric characteristics and dietary habits are widely recognized to influence blood pressure. We evaluated their role in a large series of Mediterranean adult women. METHODS: In Florence, in the European Prospective Investigation into Cancer and Nutrition, we recruited 10 083 women, aged 35-64 years. Detailed information on diet, lifestyle, physical activity, and medical history were collected. Anthropometric indices and systolic and diastolic blood pressures were measured at recruitment using standardized procedures. Overall, after excluding those women who reported a clinical diagnosis of hypertension and/or an antihypertensive treatment and those without measurements, 7601 women were available for analyses with an average systolic and diastolic blood pressure value of 123.2+/-16.0 and 78.7+/-9.4 mmHg, respectively. RESULTS: Multivariate regression models showed that body mass index (P<0.0001) and waist circumference (>or=88 cm, P<0.0001), as well as processed meat, potatoes, and wine consumption, were directly associated with both systolic and diastolic values. In contrast, a high consumption of selected foods resulted inversely associated with systolic (total vegetables, yoghurt, and eggs), diastolic (olive oil) or both systolic and diastolic values (leafy vegetables, milk, coffee). Analyses performed on nutrients showed a positive association with alcohol and sodium intake, and an inverse one with potassium and micronutrients derived from fruits and vegetables. CONCLUSION: In this large series of women from Tuscany, Central Italy, we confirm the independent influence of anthropometric characteristics on blood pressure. The role of specific foods and nutrients in modulating blood pressure also emerged, suggesting a central role for lifestyle modifications in blood pressure control.

Enhanced expression of Lp-PLA2 and lysophosphatidylcholine in symptomatic carotid atherosclerotic plaques.

BACKGROUND AND PURPOSE: Circulating lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has emerged as a novel biomarker for cardiovascular diseases. However, the correlation between the plaque expression of Lp-PLA(2) and plaque oxidative stress, inflammation, and stability as well as the clinical presentation remains poorly defined, especially for cerebrovascular disease. Therefore, this study was performed to test the hypothesis that Lp-PLA(2) expression is higher in symptomatic than in asymptomatic carotid plaques of patients undergoing carotid endarterectomy. METHODS: The expression of Lp-PLA(2) in 167 carotid artery plaques was determined by immunoblotting and immunostaining. Plaque oxidative stress, inflammation, and stability were quantified by NAD(P)H oxidase p67phox and MMP-2 immunoblotting, oxidized LDL (oxLDL) immunoreactivity, macrophage and Sirius red collagen staining. Lysophosphatidylcholine 16:0 (lysoPC) concentration was measured in 55 plaques using liquid chromatography tandem mass spectrometry. RESULTS: Lp-PLA(2) expression was significantly higher in plaques of symptomatic patients than asymptomatic patients (1.66+/-0.19 versus 1.14+/-0.10, P<0.05) and localized mainly to shoulder and necrotic lipid core areas in colocalization with oxLDL and macrophage content. Similarly, Lp-PLA(2) expression was related to collagen content, which was lower in plaques from symptomatic patients than in plaques from asymptomatic patients (9.1+/-2.2 versus 18.5+/-1.7% of staining/field, P<0.001). LysoPC plaque concentration was significantly higher in plaques of symptomatic than asymptomatic patients (437.0+/-57.91 versus 228.84+/-37.00 mmol/L, P<0.05). CONCLUSIONS: Symptomatic carotid artery plaques are characterized by increased levels of Lp-PLA(2) and its product lysoPC in correlation with markers of tissue oxidative stress, inflammation, and instability. These findings strongly support a role for Lp-PLA2 in the pathophysiology and clinical presentation of cerebrovascular disease.

Phosphodiesterase 5 inhibition in essential hypertension.

Phosphodiesterase (PDE) 5 inhibitors reduce cyclic guanylate monophosphate breakdown, promoting vascular relaxation in the corpora cavernosa and penile erection during sexual stimulation. Sildenafil, vardenafil, and tadalafil were approved as effective treatments for male erectile dysfunction. Because PDE5 is present in artery and vein smooth muscle cells throughout the body, PDE5 inhibitors have mild systemic vasodilatory effects and thus the potential to impact the vascular system. The US Food and Drug Administration has approved PDE5 inhibitors for treating pulmonary hypertension. Moreover, their systemic vasodilating properties theoretically make these drugs suitable for treating hypertension. Studies indicate that PDE5 inhibition may be an option for reducing blood pressure in hypertensive patients. Additional benefits may be related to improved arterial stiffness and endothelial dysfunction, two early vascular abnormalities characterizing essential hypertension. More investigation is needed on PDE5 inhibitors as antihypertensive drugs, especially with slow-release formulations or compounds with long half-life. Studies on safety during long-term administration, interactions with antihypertensive and nonantihypertensive drugs, and effect on target organ damage are needed.

Non-invasive diagnostic tools for investigating endothelial dysfunction.

The endothelium is not merely a barrier but it plays a key role in the maintenance of vascular homeostasis. A dysfunctional endothelium is an early marker of the development of atherosclerotic changes and can also contribute to cardiovascular events. Vascular reactivity tests represent the most widely used methods in the clinical assessment of endothelial function and in the last two decades, several methodologies were developed to study it non invasively in the peripheral macrocirculation (conduit arteries) and microcirculation (resistance arteries and arterioles). This review will centre on the most relevant available non-invasive techniques in the research on endothelial function, their advantages and limitations. Flow mediated dilation (FMD) of the brachial artery by ultrasounds is the most widely used vascular test to assess endothelium-dependent vasodilation. Other approaches include measurement of microcirculatory reactive hyperaemia by forearm venous pletysmography or digital pulse amplitude tonometry, response to beta2 agonist by applanation tonometry or digital photoplethysmography and several test by skin laser doppler. It appears that FMD is the most reproducible test when an appropriate and accurate methodology is applied. Recently, post-ischemic vasodilation in the cavernous arteries was also suggested to study endothelial function in patients with erectile dysfunction. Systemic markers proposed as measures of NO biology, inflammatory cytokines, adhesion molecules, or markers of endothelial damage and repair have only a very limited role as a result of biological and assay availability and variability, these factors currently have a limited role in the assessment of individual patients. The optimal methodology for investigating the multifaceted aspects of endothelial dysfunction is still under debate. Therefore, no available test to assess endothelial function has sufficient sensitivity and specificity to be used yet in clinical practice. Only the growing concordant results from different reproducible and reliable non-invasive methods exploring endothelial function with different stimuli will support and strengthen experimental findings, thus providing conclusive answers in this area of research.

Omega 3 : where do we stand?

Omega-3 fatty acids are essential polyunsaturated fatty acids that are crucial components of plasma membrane phospholipids. They influence cell structure and function and have anti-thrombotic and anti-arrhythmic properties, thus potentially exerting a favourable action on primary and secondary prevention of cardiovascular events. However, the supposed beneficial effect of omega-3 fatty acids in the management of cardiovascular risk has been evaluated only in a relatively small number of interventional studies, with results that are not consistent and are only suggestive of a putative beneficial effect of omega-3 supplementation on the prevention of cardiovascular mortality. Benefits have been reported mainly for the prevention of sudden death in patients with recent myocardial infarction and for primary and secondary prevention of nonfatal cardiac events in populations with high fish intake. Therefore, only ongoing trials will provide definitive data to elucidate whether omega-3 fatty acids could represent a new therapeutic approach for cardiovascular disease.

Placenta growth factor expression in human atherosclerotic carotid plaques is related to plaque destabilization.

BACKGROUND AND PURPOSE: Placenta growth factor (PlGF) mediates angiogenesis and inflammation, but its role in human atherosclerosis is unknown. This study was designed to test the hypothesis that PlGF-expression in human atherosclerotic carotid plaques is related to inflammation, vascularization and clinical plaque instability. METHODS: The expression of PlGF, C-reactive protein (CRP) and CD40L was analyzed with Western blots in carotid plaques of 60 patients. Cellular infiltration (CD68, CD3) and vascularization (von-Willebrand-factor) was assessed by immunohistochemistry. RESULTS: Symptomatic patients showed higher levels of PlGF than asymptomatic patients (115.4+/-8.2 versus 83.6+/-10.5 densitometric units (DU), p<0.05) and higher grading for inflammatory cells and microvessels (CD3: 2.3+/-0.1 versus 0.6+/-0.1, p<0.001, CD68: 2.4+/-0.1 versus 0.8+/-0.1, p<0.001, microvessels: 2.3+/-0.1 versus 1.5+/-0.1, p<0.01). PlGF-expression showed a positive correlation to the expression of CRP (r=0.5, p<0.001) and CD40L (r=0.4, p<0.01). CONCLUSIONS: PlGF-expression within human atherosclerotic lesions is associated with plaque inflammation and microvascular density, suggesting a role for PlGF in plaque destabilization and, thus, in clinical manifestation of the disease.

Differential distribution of vasa vasorum in different vascular beds in humans.

OBJECTIVE: Vasa vasorum (VV) have been implicated to play a role in the pathogenesis of atherosclerosis. This study was designed to describe the distribution of VV density in different vascular beds in humans and to investigate the association between VV density and the known distribution of atherosclerosis in human arteries. METHODS: Forty-two human arteries, harvested at autopsy or after explantation, were analyzed by three-dimensional microscopic-computed tomography (micro-CT). VV density, endothelial-surface-fraction (Sigma VV endothelial-surface-area/vessel-wall-volume) and vascular-area-fraction (Sigma VV area/vessel-wall-area) were calculated for coronary, renal and femoral arteries. Representatively five coronary, renal and femoral arteries were stained for endothelial cells (von Willebrand-Factor), macrophages (CD68), vascular endothelial growth factor (VEGF) and collagen (Sirius Red). RESULTS: Coronary arteries showed a higher VV density compared to renal and femoral arteries (2.12+/-0.26 n/mm(2) versus 0.61+/-0.06 n/mm(2) and 0.66+/-0.11 n/mm(2); P<0.05 for both) as well as a higher endothelial-surface-fraction and vascular-area-fraction. Histology showed a positive correlation between histologically derived VV density and CD68-positive cells/area (r=0.54, P<0.01), VEGF-immunoreactivity/area (r=0.55, P<0.01) and a negative correlation between VV density and collagen I content (r=0.66, P<0.05). CONCLUSION: This micro-CT study highlights a higher VV density in coronary than in peripheral arteries, supporting the relation between VV density and the susceptibility to atherosclerosis in different vascular beds in humans.