Endothelial nitric oxide synthase gene transfer restores endothelium-dependent relaxations and attenuates lesion formation in carotid arteries in apolipoprotein E-deficient mice.

Nitric oxide (NO) and monocyte chemoattractant protein-1 (MCP-1) exert partly opposing effects in vascular biology. NO plays pleiotropic vasoprotective roles including vasodilation and inhibition of platelet aggregation, smooth muscle cell proliferation, and endothelial monocyte adhesion, the last effect being mediated by MCP-1 downregulation. Early stages of arteriosclerosis are associated with reduced NO bioactivity and enhanced MCP-1 expression. We have evaluated adenovirus-mediated gene transfer of human endothelial NO synthase (eNOS) and of a N-terminal deletion (8ND) mutant of the MCP-1 gene that acts as a MCP-1 inhibitor in arteriosclerosis-prone, apolipoprotein E-deficient (ApoE(-/-)) mice. Endothelium-dependent relaxations were impaired in carotid arteries instilled with a noncoding adenoviral vector but were restored by eNOS gene transfer (p < 0.01). A perivascular collar was placed around the common carotid artery to accelerate lesion formation. eNOS gene transfer reduced lesion surface areas, intima/media ratios, and macrophage contents in the media at 5-week follow-up (p < 0.05). In contrast, 8ND-MCP-1 gene transfer did not prevent lesion formation. In conclusion, eNOS gene transfer restores endothelium-dependent vasodilation and inhibits lesion formation in ApoE(-/-) mouse carotids. Further studies are needed to assess whether vasoprotection is maintained at later disease stages and to evaluate the long-term efficacy of eNOS gene therapy for primary arteriosclerosis.

The impact of carotid plaque screening on motivation for smoking cessation.

Showing smokers their own atherosclerotic plaques might increase motivation for smoking cessation, since they underestimate their own risk for smoking-related diseases. To assess the feasibility and optimal processes of studying the impact of carotid atherosclerotic plaque screening in smokers, we enrolled 30 daily cigarette smokers, aged 40-70 years, in an observational pre-post pilot study. All smokers underwent smoking cessation counseling, nicotine replacement therapy, a carotid ultrasound, an educational tutorial on atherosclerosis, baseline and 2-month motivation to change assessment, and assessment of smoking cessation at 2 months. Participants had a mean smoking duration of 34 years (SD = 7). Carotid plaques were present in 22 smokers (73%). Between baseline and 2 months after plaque screening, motivation for smoking cessation increased from 7.4 to 8.4 out of 10 (p = .02), particularly in those with plaques (7.2 to 8.7, p = .008). At 2 months, the smoking quit rate was 63%, with a quit rate of 73% in those with plaques vs. 38% in those without plaques (p = .10). Perceived stress, anxiety, and depression did not increase after screening. 96% of respondents answered correctly at least 80% of questions regarding atherosclerosis knowledge at baseline and after 2 months. In conclusion, studying the process of screening for carotid plaques for the purpose of increasing motivation for smoking cessation, in addition to counseling and drug therapy for smoking cessation in long-term smokers, appears feasible. The impact of carotid plaque screening on smoking cessation should be examined in larger randomized controlled trials with sufficient power to assess the impact on long-term smoking cessation rates.

Resistance of the internal mammary artery to restenosis: a histomorphologic study of various porcine arteries.

BACKGROUND/AIMS: Restenosis after percutaneous transluminal angioplasty (PTA) of the internal mammary artery (IMA) grafts is much less pronounced than in other arteries and venous grafts. The aim of the study was to test whether various arteries respond differently to dilatation. METHODS: PTA of the IMA, carotid, renal and circumflex coronary (RCx) arteries was performed in 9 pigs (balloon to artery ratio of 1:1.5). After 8 weeks, angiography was repeated and vessels prepared for histological analysis. Immunohistochemical staining was done to examine proliferative activity (Ki67) and to identify the vasa vasorum of the adventitia (F VIII-RA). RESULTS: The intima-media ratio after PTA was lowest in the IMA (0.06), followed by the carotid (0.27) and renal arteries (0.49) and the RCx (0.69). Proliferation of the intima was seen at 287 degrees of the vessel circumference in the RCx, at 286 degrees in the renal and at 166 degrees in the carotid artery. No proliferative activity was seen in the IMA. The intima-adventitia ratio was lower in the IMA than in the RCx and renal arteries (p &lt; 0.05). CONCLUSION: Intima proliferation after PTA varies between the different vessels, with best results seen in the IMA. There are differences in remodeling after PTA between muscular, muscular/elastic and elastic arteries.

The Impact of CAROtid plaque Screening on Smoking (CAROSS) cessation and control of other cardiovascular risk factors: rationale and design of a randomized controlled trial

BACKGROUND: Screening tests for subclinical cardiovascular disease, such as markers of atherosclerosis, are increasingly used in clinical prevention to identify individuals at high cardiovascular risk. Being aware of these test results might also enhance patient motivation to change unhealthy behaviors but the effectiveness of such a screening strategy has been poorly studied. METHODS: The CAROtid plaque Screening trial on Smoking cessation (CAROSS) is a randomized controlled trial in 530 regular smokers aged 40-70 years to test the hypothesis that carotid plaque screening will influence smokers' behavior with an increased rate of smoking cessation (primary outcome) and an improved control of other cardiovascular risk factors (secondary outcomes) after 1-year follow-up. All smokers will receive a brief advice for smoking cessation,and will subsequently be randomly assigned to either the intervention group (with plaques screening) or the control group (without plaque screening). Carotid ultrasound will be conducted with a standard protocol. Smokers with at least one carotid plaque will receive pictures of their own plaques with a structured explanation on the general significance of plaques. To ensure equal contact conditions, smokers not undergoing ultrasound and those without plaque will receive a relevant explanation on the risks associated with tobacco smoking. Study outcomes will be compared between smokers randomized to plaque screening and smokers not submitted to plaque screening. SUMMARY: This will be the first trial to assess the impact of carotid plaque screening on 1-year smoking cessation rates and levels of control of other cardiovascular risk factors.

Chronic nitric oxide synthase inhibition and carotid artery distensibility in renal hypertensive rats.

The goal of the present study was to examine the viscoelastic properties of the carotid artery in genetically identical rats exposed to similar levels of blood pressure sustained by different mechanisms. Eight-week old male Wistar rats were examined 2 weeks after renal artery clipping (two-kidney, one clip [2K1C] Goldblatt rats, n = 53) or sham operation (n = 49). One half of the 2K1C and sham rats received the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 1.48 mmol/L) in their drinking water for 2 weeks after the surgical procedure. Mean blood pressure increased significantly in the 2K1C-water (182 mm Hg), 2K1C-L-NAME (197 mm Hg), and sham-L-NAME (170 mm Hg) rats compared with the sham-water rats (127 mm Hg). Plasma renin activity was not altered by L-NAME but significantly enhanced after renal artery clipping. A significant and similar increase in the cross-sectional area of the carotid artery was observed in L-NAME and vehicle-treated 2K1C rats. L-NAME per se did not modify cross-sectional area in the sham rats. There was a significant upward shift of the distensibility-pressure curve in the L-NAME- and vehicle-treated 2K1C rats compared with the sham-L-NAME rats. L-NAME treatment did not alter the distensibility-pressure curve in the 2K1C rats. These results demonstrate that the mechanisms responsible for artery wall hypertrophy in renovascular hypertension are accompanied by an increase in arterial distensibility that is not dependent on the synthesis of nitric oxide.

Total aortic arch stenting--hemodynamical impact of carotid artery perfusion.

The aim of this experimental study is to evaluate the feasibility and the outcome of total endovascular stent implantation in the aortic arch. Indications for this operation-technique would be acute or chronic dissection of the aortic arch (non-A-non-B dissection) or type B dissection with retrograde extension. Four pigs were canulated via the distal abdominal aorta and a retrograde placement of a Djumbodis arch stent (4-9 cm) was controlled by using intravascular ultrasound and intracardiac ultrasound by the inferior cava vein and under radioscopic control. Cerebral perfusion, by using a flow meter placed on one prepared carotid artery, were controlled before, immediate post-procedural (<1 min), and in the early follow-up after aortic arch stent implantation. During the implantation process, especially during balloon inflation and deflation, mean carotid perfusion decreases slightly. A reactive increase of carotid perfusion after stent placements indicates transitory cerebral hypo-perfusion. Non-covered aortic arch stent implantation is technically feasible and could be a potential treatment option in otherwise inoperable arch dissections. The time required for balloon inflation and deflation causes an important risk of cerebral ischemia. The latter can be reduced by transaxillary perfusion.

Vasopressin dilates the rat carotid artery by stimulating V1 receptors.

The acute effects of various vasopressor agents on the diameter of the common carotid artery were studied in halothane-anesthetized normotensive rats. The animals were infused intravenously for 60 min with equipressor doses of angiotensin II (10 ng/min), the alpha1-stimulant methoxamine (5 microg/min), lysine vasopressin (5 mU/min), or vehicle. The arterial diameter was measured by using a high-resolution ultrasonic echo-tracking device. The three vasoconstrictors increased the carotid artery diameter, but this effect was significantly more pronounced with lysine vasopressin. Even a nonpressor dose of lysine vasopressin (1 mU/min) caused a significant increase in the arterial diameter. The lysine vasopressin-induced vasodilatation could be prevented by the administration of d(CH2)5Tyr(Me)AVP (10 microg, i.v.), a selective V1-vasopressinergic receptor antagonist. These data therefore suggest that a short-term increase in blood pressure induces in rats a distention of the carotid artery. The increase in arterial diameter seems to involve an active mechanism with lysine vasopressin caused by the stimulation of V1-vasopressinergic receptors.

Carotid Dose Spring in Definitive Irradiation of T1N0 Squamous Cell Laryngeal Carcinoma Using Helical Tomotherapy

Purpose/Objective(s): To implement a carotid dose sparing protocol using helical Tomotherapy in T1N0 squamous cell laryngeal carcinoma.Materials/Methods: Between July and August 2010, 7 men with stage T1N0 laryngeal carcinoma were included in this study. Age ranged from 47 - 74 years. Staging included endoscopic examination, CT-scan and MRI when indicated. Planned irradiation dose was 70 Gy in 35 fractions over 7 weeks. A simple treatment planning algorithm for carotid sparing was used: maximum point dose to the carotids 35 Gy, to the spinal cord 30 Gy, and 100% PTV volume to be covered with 95% of the prescribed dose. Carotid volume of interest extended to 1 cm above and below of the PTV. Doses to the carotid arteries, to the critical organs, and to the planned target volume (PTV) with our standard laryngeal irradiation protocol was compared. Daily megavoltage scans were obtained before each fraction. When necessary, the Planned Adaptive software (TomoTherapy Inc., Madison, WI) was used to evaluatethe need for a re-planning, which has never been indicated. Dose data were extracted using the VelocityAI software (Atlanta, GA), and data normalization and dose-volume histogram (DVH) interpolation were realized using the Igor Pro software (Portland, OR).Results:A significant (p\0.05) carotid dose sparing compared to our standard protocol with an average maximum point dose of 38.3 Gy (standard deviation [SD] 4.05 Gy), average mean dose of 18.59 Gy (SD 0.83 Gy) was achieved. In all patients, 95% of the carotid volume received less than 28.4 Gy (SD 0.98 Gy). The average maximum point dose to the spinal cord was 25.8 Gy (SD 3.24 Gy). PTV was fully covered with more than 95% of the prescribed dose for all patients with an average maximum point dose of 74.1 Gy and the absolute maximum dose in a single patient of 75.2 Gy. To date, the clinical outcomes have been excellent. Three patients (42%) developed stage 1 mucositis that was conservatively managed, and all the patients presented a mild to moderate dysphonia. All adverse effects resolved spontaneously in the month following the end of treatment. Early local control rate is 100% considering a 4 - 5 months post treatment follow-up.Conclusions: Helical Tomotherapy allows a clinically significant decrease of carotid irradiation dose compared to standard irradiation protocols with an acceptable spinal cord dose tradeoff. Moreover, this technique allows the PTV to be homogenously covered with a curative irradiation dose. Daily control imaging brings added security margins especially when working with high dose gradients. Further investigations and follow-up are underway to better evaluate the late clinical outcomes especially the local control rate, late laryngeal and vascular toxicity, and expected potential impact on cerebrovascular events.

Carotid sparing in definitive irradiation of T1N0 squamous cell larnyx cancer using helical tomotherapy

Objective: To implement a carotid sparing protocol using helical Tomotherapy(HT) in T1N0 squamous-cell laryngeal carcinoma.Materials/Methods: Between July and August 2010, 7 men with stage T1N0 laryngeal carcinoma were included in this study. Age ranged from 47-74 years. Staging included endoscopic examination, CT-scan and MRI when indicated.Planned irradiation dose was 70 Gy in 35 fractions over 7 weeks. A simple treatment planning algorithm for carotidsparing was used: maximum point dose to the carotids 35 Gy, to the spinal cord 30 Gy, and 100% PTV volume to becovered with 95% of the prescribed dose. Carotid volume of interest extended to 1 cm above and below of the PTV.Doses to the carotid arteries, critical organs, and planned target volume (PTV) with our standard laryngealirradiation protocol was compared. Daily megavoltage scans were obtained before each fraction. When necessary, thePlanned Adaptive? software (TomoTherapy Inc., Madison, WI) was used to evaluate the need for a re-planning,which has never been indicated. Dose data were extracted using the VelocityAI software (Atlanta, GA), and datanormalization and dosevolume histogram (DVH) interpolation were realized using the Igor Pro software (Portland,OR).Results: A significant (p < 0.05) carotid dose sparing compared to our standard protocol with an average maximum point dose of 38.3 Gy (standard devaition [SD] 4.05 Gy), average mean dose of 18.59 Gy (SD 0.83 Gy) was achieved.In all patients, 95% of the carotid volume received less than 28.4 Gy (SD 0.98 Gy). The average maximum point doseto the spinal cord was 25.8 Gy (SD 3.24 Gy). PTV was fully covered with more than 95% of the prescribed dose forall patients with an average maximum point dose of 74.1 Gy and the absolute maximum dose in a single patient of75.2 Gy. To date, the clinical outcomes have been excellent. Three patients (42%) developed stage 1 mucositis that was conservatively managed, and all the patients presented a mild to moderate dysphonia. All adverse effectsresolved spontaneously in the month following the end of treatment. Early local control rate is 100% considering a 4-5months post treatment follow-up.Conclusions: HT allows a clinically significant decrease of carotid irradiation dose compared tostandard irradiation protocols with an acceptable spinal cord dose tradeoff. Moreover, this technique allows the PTV to be homogenously covered with a curative irradiation dose. Daily control imaging brings added security marginsespecially when working with high dose gradients. Further investigations and follow-up are underway to better evaluatethe late clinical outcomes especially the local control rate, late laryngeal and vascular toxicity, and expected potentialimpact on cerebrovascular events.

Phase-sensitive dual-inversion recovery for accelerated carotid vessel wall imaging.

OBJECTIVES: Dual-inversion recovery (DIR) is widely used for magnetic resonance vessel wall imaging. However, optimal contrast may be difficult to obtain and is subject to RR variability. Furthermore, DIR imaging is time-inefficient and multislice acquisitions may lead to prolonged scanning times. Therefore, an extension of phase-sensitive (PS) DIR is proposed for carotid vessel wall imaging. METHODS: The statistical distribution of the phase signal after DIR is probed to segment carotid lumens and suppress their residual blood signal. The proposed PS-DIR technique was characterized over a broad range of inversion times. Multislice imaging was then implemented by interleaving the acquisition of 3 slices after DIR. Quantitative evaluation was then performed in healthy adult subjects and compared with conventional DIR imaging. RESULTS: Single-slice PS-DIR provided effective blood-signal suppression over a wide range of inversion times, enhancing wall-lumen contrast and vessel wall conspicuity for carotid arteries. Multislice PS-DIR imaging with effective blood-signal suppression is enabled. CONCLUSIONS: A variant of the PS-DIR method has successfully been implemented and tested for carotid vessel wall imaging. This technique removes timing constraints related to inversion recovery, enhances wall-lumen contrast, and enables a 3-fold increase in volumetric coverage at no extra cost in scanning time.

An angiotensin II- and NF-kappaB-dependent mechanism increases connexin 43 in murine arteries targeted by renin-dependent hypertension.

AIMS: Connexins (Cxs) play a role in the contractility of the aorta wall. We investigated how connexins of the endothelial cells (ECs; Cx37, Cx40) and smooth muscle cells (SMCs; Cx43, Cx45) of the aorta change during renin-dependent and -independent hypertension. METHODS AND RESULTS: We subjected both wild-type (WT) mice and mice lacking Cx40 (Cx40(-/-)), to either a two-kidney, one-clip procedure or to N-nitro-l-arginine-methyl-ester treatment, which induce renin-dependent and -independent hypertension, respectively. All hypertensive mice featured a thickened aortic wall, increased levels of Cx37 and Cx45 in SMC, and of Cx40 in EC (except in Cx40(-/-) mice). Cx43 was up-regulated, with no effect on its S368 phosphorylation, only in the SMCs of renin-dependent models of hypertension. Blockade of the renin-angiotensin system of Cx40(-/-) mice normalized blood pressure and prevented both aortic thickening and Cx alterations. Ex vivo exposure of WT aortas, carotids, and mesenteric arteries to physiologically relevant levels of angiotensin II (AngII) increased the levels of Cx43, but not of other Cx. In the aortic SMC line of A7r5 cells, AngII activated kinase-dependent pathways and induced binding of the nuclear factor-kappa B (NF-kappaB) to the Cx43 gene promoter, increasing Cx43 expression. CONCLUSION: In both large and small arteries, hypertension differently regulates Cx expression in SMC and EC layers. Cx43 is selectively increased in renin-dependent hypertension via an AngII activation of the extracellular signal-regulated kinase and NF-kappaB pathways.

Diabetes and pre-diabetes are associated with cardiovascular risk factors and carotid/femoral intima-media thickness independently of markers of insuline resistance and adiposity

Background Impaired glucose regulation (IGR) is associated with detrimental cardiovascular outcomes such as cardiovascular disease risk factors (CVD risk factors) or intima-media thickness (IMT). Our aim was to examine whether these associations are mediated by body mass index (BMI), waist circumference (waist) or fasting serum insulin (insulin) in a population in the African region. Methods Major CVD risk factors (systolic blood pressure, smoking, LDL-cholesterol, HDL-cholesterol,) were measured in a random sample of adults aged 25-64 in the Seychelles (n=1255, participation rate: 80.2%). According to the criteria of the American Diabetes Association, IGR was divided in four ordered categories: 1) normal fasting glucose (NFG), 2) impaired fasting glucose (IFG) and normal glucose tolerance (IFG/NGT), 3) IFG and impaired glucose tolerance (IFG/IGT), and 4) diabetes mellitus (DM). Carotid and femoral IMT was assessed by ultrasound (n=496). Results Age-adjusted levels of the major CVD risk factors worsened gradually across IGR categories (NFG < IFG/NGT < IFG/IGT < DM), particularly HDL-cholesterol and blood pressure (p for trend <0.001). These relationships were marginally attenuated upon further adjustment for waist, BMI or insulin (whether considered alone or combined) and most of these relationships remained significant. With regards to IMT, the association was null with IFG/NGT, weak with IFG/IGT and stronger with DM (all more markedly at femoral than carotid levels). The associations between IMT and IFG/IGT or DM (adjusted by age and major CVD risk factors) decreased only marginally upon further adjustment for BMI, waist or insulin. Further adjustment for family history of diabetes did not alter the results. Conclusions We found graded relationships between IGR categories and both major CVD risk factors and carotid/femoral IMT. These relationships were only partly accounted for by BMI, waist and insulin. This suggests that increased CVD-risk associated with IGR is also mediated by factors other than the considered markers of adiposity and insulin resistance. The results also imply that IGR and associated major CVD risk factors should be systematically screened and appropriately managed.

Assessment of the carotid artery by MRI at 3T: a study on reproducibility

PURPOSE: To examine the reproducibility of carotid artery dimension measurements using 3T MRI. MATERIALS AND METHODS: Ten healthy volunteers underwent three scans on two occasions for assessment of total vessel wall area (TVWA), total luminal area (TLA), and minimum (MinT) and maximum (MaxT) vessel wall thickness. A double inversion-recovery (IR) fast gradient-echo (FGRE) sequence was used on a commercial 3T system. During the first visit the subjects were scanned twice. The third scan was performed at least four days later. One observer traced all scans, and a second observer retraced the first scan series. RESULTS: For TVWA an interclass correlation (ICC) of 0.994 was calculated with all three scans taken into account. The interobserver ICC was 0.984. The agreement between the scans for TLA showed an ICC of 0.982 with an interobserver ICC of 0.998. For MinT and MaxT an ICC of 0.843 and 0.935 were calculated, with interobserver ICCs of 0.860 and 0.726, respectively. CONCLUSION: With the use of a commercial 3T MR system, TVWA, TLA, and wall thickness measurements of the carotid artery can be assessed with good reproducibility.