Restenosis rates following vascular interventions still limit their long-term success. Oxidative stress plays a relevant role in this pathophysiological phenomenon, but less attention has been devoted to its effects on DNA damage and to the subsequent mechanisms of repair. In the present study, we analysed in a model of arteriotomy-induced stenosis in rat carotid arteries the time-dependent expression of DNA damage markers and of DNA repair genes, together with the assessment of proliferation and apoptosis indexes. The expression of the oxidative DNA damage marker 7,8-dihydro-8-oxo-2′-deoxyguanosine was increased at 3 and 7 days after arteriotomy, with immunostaining distributed in the injured vascular wall and perivascular tissue. Expression of the DNA damage marker phospho-H2A.X was less relevant, but increased from 4 h to 7 days after arteriotomy, with immunostaining prevalently present in the adventitia and, to a lesser extent, in medial smooth muscle cells at the injury site. RT (reverse transcription)–PCR indicated a decrease in eight out of 12 genes involved in the DNA repair machinery we selected from 4 h to 7 days after arteriotomy, with the exception of an increase in the Mutyh and Slk genes ( P <0.05). Western blot analysis revealed a decrease in p53 and catalase at 3 days after arteriotomy ( P <0.05). A maximal 7% of BrdU-positive cells in the endothelium and media occurred at 7 days after arteriotomy, whereas the apoptotic index peaked at 3 days after injury ( P <0.05). In conclusion, our results highlight a persistent DNA damage, presumably related to a temporary decrease in the expression of the DNA repair machinery and of the antioxidant enzyme catalase, playing a role in stenosis progression.

Individuals suffering from ATH (adult-type hypolactasia), defined by the LCT (gene encoding lactase-phlorizin hydrolase) C/C −13910 genotype (rs4988235), use less milk and dairy products and may have higher plasma HDL (high-density lipoprotein) and lower triacylglycerol (triglyceride) concentrations than their counterparts without ATH. To investigate the effects of ATH status on the early markers of atherosclerosis, we examined its association with CIMT (carotid intima-media thickness), CAC (carotid artery compliance) and brachial artery FMD (flow-mediated dilation) in a young population-based cohort of otherwise healthy individuals. As part of the Cardiovascular Risk in Young Finns Study, we performed CIMT, CAC and FMD analyses, LCT C/T −13910 genotyping and risk factor determination in 2109 young subjects 24–39 years of age (45% males) at the time of the examination. The consumption of both milk and dairy products was lowest and the consumption of alcohol highest in subjects with the C/C −13910 genotype ( P <0.001 for all) in comparison with subjects without ATH (TT+CT). In multivariate analysis, no significant association between ATH status and CIMT, CAC or brachial artery FMD was found after adjustment for the use of alcohol, dairy products and all other major risk factors of coronary artery disease. In otherwise similar statistical analysis, the results remained non-significant when females and males were analysed in their own groups. In conclusion, the finding does not support the involvement of ATH in the pathogenesis of early atherosclerosis.

Systemic arterial compliance has been known to increase during healthy pregnancy, whereas, recently, the carotid artery has been reported to stiffen. To clarify this controversy, we simultaneously measured aortic PWV (pulse wave velocity) and carotid artery elastic parameters in a cohort of pregnant women. Twelve normotensive pregnant women were studied longitudinally during the three trimesters of pregnancy (T 1 , T 2 and T 3 respectively) and 12 weeks PP (postpartum). Carotid artery diastolic diameter and pulsatile distension was measured by an echo-wall tracking method and carotid pulse pressure by applanation tonometry. Carotid strain, compliance, distensibility coefficient, stiffness index β, E inc (incremental elastic modulus) and augmentation index were calculated. Aortic PWV was determined to estimate aortic distensibility. All carotid artery elastic parameters indicated significant stiffening from T 1 to T 3 (1.8±0.2 versus 2.9±0.3 mmHg for E inc ), which was reversed after delivery (2.3±0.2 mmHg). Aortic PWV decreased during pregnancy (6.2±0.2 versus 5.4±0.2 m/s) and increased in the PP period (6.7±0.2 m/s). No correlation was found between changes in carotid artery elastic parameters and changes in aortic PWV either from T 1 to T 3 or from T 3 to PP. The carotid artery exhibits regionally specific stiffening during pregnancy, which appears to represent a qualitatively different change in arterial elastic behaviour.

Stiffening of the barosensory vessel wall in hypertension has been suggested to play a role in the associated baroreflex impairment. The carotid distensibility–BRS (baroreflex sensitivity) relationship, however, has not been studied in pre-eclampsia, a condition where hypertension is spontaneously reversible. Twelve normotensive pregnant women and 12 patients with pre-eclampsia matched for maternal age and week of gestation were studied in the third trimester and 3 months postpartum. Carotid artery diastolic diameter and pulsatile distension was measured by echo-wall tracking and carotid pulse pressure by applanation tonometry, and the carotid distensibility coefficient was calculated. Spontaneous BRS was determined by the sequence and spectral methods from 10 min continuous recording of ECG and finger arterial blood pressure. In the third trimester, carotid distensibility was lower in patients with pre-eclampsia than in normotensive pregnant women (2.47±0.17 compared with 4.08±0.16×10 −3 /mmHg); postpartum, it increased moderately in patients, but remained below normotensive values (3.25±0.12 compared with 4.25±0.19×10 −3 /mmHg). In the third trimester, both patients and healthy pregnant women had equally low BRS values; postpartum, the various BRS indices increased markedly (by 60–190%) and to the same level in both groups. No correlation was found between changes in carotid artery distensibility and those in BRS from the third trimester to postpartum period in patients and healthy pregnant women. The lack of association between changes in carotid distensibility and BRS suggest that stiffening of the carotid artery in pre-eclampsia is not responsible for baroreflex dysfunction.

The direct vasodilatory and negative chronotropic effects of adenosine in humans are counterbalanced by a reflex increase in sympathetic nerve traffic. A suggested mechanism for this reflex includes peripheral chemoreceptor activation. We, therefore, assessed the contribution of carotid chemoreceptors to sympatho-excitation by adenosine. Muscle sympathetic nerve activity was recorded during adenosine infusion (140 µg·kg -1 ·min -1 for 5 min) in five patients lacking carotid chemoreceptors after bilateral carotid body tumour resection (one male and four female, mean age 51±11 years) and in six healthy controls (two male and four female, mean age 50±7 years). Sympathetic responses to sodium nitroprusside injections were assessed to measure baroreceptor-mediated sympathetic activation. In response to adenosine, controls showed no change in blood pressure, an increase in heart rate (+48.2±13.2%; P <0.003) and an increase in sympathetic nerve activity (+195±103%; P <0.022). In contrast, patients showed a decrease in blood pressure (-14.6±4.9/-17.6±6.0%; P <0.05), an increase in heart rate (+25.3±8.4%; P <0.032) and no significant change in sympathetic activity. Adenosine-induced hypotension in individual patients elicited less sympathetic activation than equihypotensive sodium nitroprusside injections. In humans lacking carotid chemoreceptors, adenosine infusion elicits hypotension due to the absence of significant sympatho-excitation. Chemoreceptor activation is essential for counterbalancing the direct vasodilation by adenosine. In addition, blunting of the baroreflex sympathetic response to adenosine-induced hypotension may indicate a direct sympatho-inhibitory effect of adenosine.

The relationship between levels of circulating intercellular cell-adhesion molecule-1 (cICAM-1) or P-selectin (cP-selectin) and the severity of carotid atherosclerosis was examined in 301 outpatients undergoing duplex ultrasonographic examination. Carotid plaque was defined as an intima-media thickness greater than 1.0 mm, and a plaque score (PS) was calculated from the plaque thickness in both carotid arteries. Multivariate analysis demonstrated significant positive associations between cICAM-1 and the number of plaques [β = 0.11; confidence interval (CI), 0.007–0.213], maximum intima-media thickness (β = 0.11; CI, 0.01–0.219), and PS (β = 0.10; CI, 0.001–0.205). In contrast, no significant association was found for cP-selectin. cP-selectin did not increase until atherosclerosis was advanced (PS > 10), showing a marked increase in patients with ≥ 50% stenosis. The circulating levels of both proteins are related to real measurements of plaque formation in the carotid arteries independently of classical risk factors. Marked elevation of cP-selectin occurs in advanced carotid atherosclerosis after gradual elevation of cICAM-1.

This study investigated vascular reactivity in response to acetylcholine, in the presence of acute inhibition of nitric oxide synthase, in the carotid artery and aorta of obese C57Bl6/J mice fed on a high-fat diet for 30 weeks, and of control mice. A subgroup of obese animals was also treated with the ET A receptor antagonist darusentan (50mg·kg -1 ·day -1 ). In vascular rings from control animals, acetylcholine caused endothelium-dependent contractions in the carotid artery, but not in the aorta. In vascular rings from obese mice, contractility to acetylcholine was also evident in the aorta, and that in the carotid artery was increased compared with control mice. ET A receptor blockade by darusentan treatment of the obese mice prevented enhanced vasoconstriction to acetylcholine, resulting in mild vasodilatation. Thus obesity increases endothelium-dependent vasoconstriction in the absence of endothelial nitric oxide. This effect can be completely prevented by chronic ET A receptor blockade, suggesting that endothelin modulates increased endothelium-dependent vasoconstriction in obesity.

Although the aetiology of Williams syndrome (WS) is related to elastin gene disruption, its pathogenesis remains unknown, particularly that of vascular lesions. The aim of the present study was to compare the elastic properties of three WS patients with age- and gender-matched normotensive and hypertensive controls. Common carotid arteries of WS patients had a higher distensibility, a thicker intima-media and a lower elastic modulus. Electron microscopy studies of one WS renal artery showed major abnormalities of the elastic fibres, which displayed a reticular structure and a thickening of the internal elastic lamina, whereas the ultrastructure of elastic fibres was normal in a control subadventitial muscular fibrodysplasia. In this WS arterial stenosis, we studied the expression patterns of several major smooth muscle (SM) phenotypic markers using immunofluorescence and used a normal renal artery as a control. In WS, SM-α-actin- and myosin-heavy-chain-positive cells contained low amounts of heavy caldesmon, and laminin-β1 chain was expressed into the basement membranes, indicating a less differentiated phenotype. In conclusion, in WS patients, the carotid artery wall was abnormally distensible and thick, and major ultrastructural abnormalities of elastic fibres were observed in association with smooth muscle cell de-differentiation. These results indicate that the haplo-insufficiency of the elastin gene in WS patients leads to abnormal elastic fibre assembly within the media. Arterial wall hypertrophy found with a primary defect in elastin may represent a major factor responsible for increased distensibility. We suggest that, in WS, the increased proliferative response and the associated de-differentiation process represent two important mechanisms underlying the matrix accumulation and the development of arterial stenosis.

Type I diabetes is associated with a high incidence of coronary heart disease (CHD), despite a normal or even increased concentration of high-density lipoprotein (HDL) cholesterol. This paradox may be explained by changes in the antioxidant capacity of HDL, related to paraoxonase (PON1) activity. HDL compositional changes in subjects with Type I diabetes may result in changes in PON1 activity that are associated with a higher incidence of CHD. Single-vertical-spin density-gradient ultracentrifugation was used to isolate seven HDL fractions from serum according to density. PON1 activity was measured in serum and in the HDL fractions using phenyl acetate as substrate. The mean recovery of PON1 activity in the HDL fractions was 87% (S.D. 12%). CHD risk was assessed using B-mode ultrasound to measure carotid artery intima-media thickness (IMT). Groups of 35 subjects with Type I diabetes {duration of diabetes 18 years (12-32 years) [median (interquartile range)]; glycated haemoglobin 7.67% (1.17%)} and 24 non-diabetic control subjects were studied. Carotid IMT was greater in the diabetic subjects [0.60 (0.55-0.70) compared with 0.55 (0.45-0.64) mm; P = 0.042] and HDL cholesterol concentration was higher [1.53 (0.36) compared with 1.32(0.34)mmol/l; P = 0.031]. There were qualitative differences in HDL in subjects with Type I diabetes: HDL particles were triacylglycerol-deplete, and there were greater numbers of the larger, more buoyant HDL particles. These properties were not those found to determine PON1 activity. PON1 activity increased as HDL particle density increased and particle size decreased; the increase in PON1 activity was associated with an increase in the ratio of the two HDL surface lipid components, phospholipid and unesterified cholesterol, as particle density increased. PON1 activity was similar in diabetic and non-diabetic subjects [121 (28) and 120 (36) μ molċmin -1 ċml -1 respectively; P = 0.887]. PON1 activity was not associated with carotid IMT in either group. Our results suggest that the PON1 activities of HDL particles relate to the density, size and composition of the particles. However, PON1 activity does not appear to contribute to the greater risk of CHD in subjects with Type I diabetes.

Increased intima-media thickness of the common carotid artery predicts increased risk of myocardial infarction and stroke. Preliminary evidence suggests that a decrease in blood pressure (BP) is associated with diminished wall thickness. It is not known if all classes of anti-hypertensive agents have similar protective effects. In this double-blind parallel-group clinical trial, 69 previously untreated patients with hypertension were allocated randomly to 1 year of treatment with either amlodipine (5-10mg daily) or lisinopril (5-20mg daily). Doxazosin and bendrofluazide were added if required to achieve BP control. After 12 months of treatment, clinic BP, ambulatory BP and cardiac mass were reduced similarly by the two treatment regimens. Common carotid artery intima-media thickness decreased by 0.048mm (95% confidence intervals -0.066, -0.031mm) in the amlodipine-treated group, but decreased by only 0.027 mm (-0.046, -0.007mm) in the lisinopril-treated group ( P < 0.05 for difference between treatments). Common carotid artery lumen diameter declined significantly only in patients treated with lisinopril [amlodipine, -0.02mm (-0.14, 0.10mm); lisinopril, -0.21mm (-0.32, -0.11mm); P < 0.02], while intima-media area declined similarly in the two treatment groups [amlodipine -1.32mm 2 (-1.91, -0.74mm 2 ), lisinopril -1.26mm 2 (-1.80, -0.72mm 2 ); not significant]. The results confirm that a decrease in BP causes regression of structural changes in the carotid artery in hypertensive patients. The nature of the structural regression differed markedly between the two treatment regimens, in spite of similar decreases in BP. The calcium channel blocker induced greater regression of common carotid artery intima-media thickness than the angiotensin-converting enzyme inhibitor. However, carotid artery wall mass, as indicated by intima-media area, was reduced to a similar extent by the two treatments. It remains to be established whether such differences confer a prognostic advantage.

1. The reproducibility of measurements of the arterial wall thickness in both the carotid and femoral artery was investigated by means of high-resolution B-mode ultrasonography. For this purpose, subjects with normal and increased intima-media thickness were selected. Images were stored on an optical disk and were analysed with a semi-automatic software program by two readers. Individuals were scanned twice by two independent observers. 2. Measurements were performed of the far and near wall of the common carotid artery and bulbous in 30 healthy subjects and 19 patients known to have an increased intima-media thickness. Far-wall measurements were made of the internal carotid artery on both sides and common femoral artery on the right side only. 3. In healthy subjects the mean within-observer coefficient of variation was 1.8% and 3.0% for the far wall in the common carotid artery on the right side and left side, respectively. For the near wall the mean coefficient of variation of the common carotid artery was 2.8% on the right and 3.4% on the left side. The mean coefficient of variation was less than 4% for both far and near wall in the bulbous and far wall in the internal carotid artery. Even in patients with increased intima-media thickness the mean coefficient of variation of each segement was less than 4.5%. In the control subjects the between-observer coefficient of variation of the common carotid artery was 2.8% and 5.1% for the far wall on the right and left side, respectively, and 3.4% and 4.2% for the near wall on the right and left side. In healthy subjects a mean difference of 0.002 mm within observers was found in the right far-wall common carotid artery, with limits of agreement of −0.048 to 0.052 mm. The coefficient of repeatability was 0.050 mm. For patients with increased intima-media thickness the mean difference in this segment was −0.006 mm (−0.094 to 0.082) with a coefficient of repeatability of 0.088 mm. For the near wall in the common carotid artery and far and near wall in the bulbous and internal carotid artery the mean differences were larger, but were all below 0.1 mm. The differences and limits of agreements increased between observers. In patients the between-observer mean difference of the far wall of the common carotid artery was −0.055 mm (−0.255 to 0.145). For the common femoral artery of normal control subjects the within- and between-observer mean differences were 0.005 mm (−0.119 to 0.129) and 0.015 mm (−0.081 to 0.111), respectively. 4. In conclusion, the reproducibility of intima-media thickness measurements in the common carotid artery is reliable, even in patients with increased artery wall thickness. Also in other segments prone to atherosclerosis, such as the bulbous, internal carotid artery and common femoral artery, a good reproducibility was found. To obtain good reproducibility it is highly recommended to use the same ultrasonographer to scan patients in follow-up studies.

1. Angiotensin II was infused into isolated, perfused pig carotid arteries. The perfusate leaving the arteries was sampled into an Auto-analyzer system which continuously monitored its composition. Arterial pressure was recorded. 2. Low, subpressor doses of angiotensin II raised the perfusate potassium concentration, whereas high doses, which produced contraction, lowered perfusate potassium and sodium concentrations. Inulin and chloride concentrations did not change. 3. The elevation of perfusate potassium with low angiotensin II dosage was appreciable compared with that caused by high doses of ouabain. 4. Neurotransmitter blockade did not alter the low- and high-dose angiotensin II effects. In other sequential dose studies, valine 5 -angiotensin II and isoleucine 5 -angiotensin II did not differ in their effects on perfusate composition or arterial contraction. 5. Mechanically increased hydrostatic pressure lowered perfusate sodium concentration, so that increased arterial pressure might have contributed to this aspect of high-dose angiotensin II effects. 6. These effects of angiotensin II might have physiological significance in relation to arterial smooth muscle and to electrolyte homeostasis.