Human urinary kininogenase reduces the endothelial injury by inhibiting Pyk2/MCU pathway

The injury of endothelial cells is one of the initiating factors in restenosis after endovascular treatment. Human urinary kallidinogenase (HUK) is a tissue kallikrein which is used for ischemia-reperfusion injury treatment. Studies have shown that HUK may be a potential therapeutic agent to prevent stenosis after vascular injury, however, the precise mechanisms have not been fully established. This study is to investigate whether HUK can protect endothelial cells after balloon injury or H2O2-induced endothelial cell damage through the proline-rich tyrosine kinase 2 (Pyk2)/mitochondrial calcium uniporter (MCU) pathway. Intimal hyperplasia, a decrease of pinocytotic vesicles and cell apoptosis were found in the common carotid artery balloon injury and H2O2-induced endothelial cell damage, Pyk2/MCU was also up-regulated in such pathological process. HUK could prevent these injuries partially via the bradykinin B2 receptor by inhibiting Pyk2/MCU pathway, which prevented the mitochondrial damage, maintained calcium balance, and eventually inhibited cell apoptosis. Furthermore, MCU expression was not markedly increased if Pyk2 was suppressed by shRNA technique in the H2O2 treatment group, and cell viability was significantly better than H2O2-treated only. In short, our results indicate that the Pyk2/MCU pathway is involved in endothelial injury induced by balloon injury or H2O2-induced endothelial cell damage. HUK plays an protective role by inhibiting the Pyk2/MCU pathway in the endothelial injury.

Exploring the mechanism of Danggui Buxue Decoction in regulating atherosclerotic disease network based on integrated pharmacological methods

OBJECTIVE

To explore the mechanism of Danggui Buxue Decoction (DGBXD) in regulating Atherosclerosis (AS) network based on integrated pharmacological methods.

METHODS

The active ingredients and targets of DGBXD are obtained from TCMSP database and ETCM. AS-related targets were collected from the Genecards and OMIM databases. The drug-disease protein interaction (PPI) networks were constructed by Cytoscape. Meanwhile, it was used to screen out densely interacting regions, namely clusters. Finally, Gene Ontology (GO) annotations are performed on the targets and genes in the cluster to obtain biological processes, and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations are performed on the targets of the PPI network to obtain signaling pathways.

RESULTS

A total of 212 known targets, 265 potential targets and 229 AS genes were obtained. The 'DGBXD known-AS PPI network' and 'DGBXD-AS PPI Network' were constructed and analyzed. DGBXD can regulate inflammation, platelet activation, endothelial cell apoptosis, oxidative stress, lipid metabolism, vascular smooth muscle proliferation, angiogenesis, TNF, HIF-1, FoxO signaling pathway, etc. The experimental data showed that compared with the model group, the expressions of ICAM-1, VCAM-1, and interleukin (IL)-1β protein and mRNA in the DGBXD group decreased (P<0.05). However, plasma IL-1β, TNF-α, and MCP-1 in the DGBXD group were not significantly different from the model group (P>0.05).

CONCLUSION

The mechanism of DGBXD in the treatment of AS may be related to the improvement of extracellular matrix (ECM) deposition in the blood vessel wall and the anti-vascular local inflammatory response, which may provide a reference for the study of the mechanism of DGBXD.

Study of Neuroprotection by a Combination of the Biological Antioxidant (Eucalyptus Extract) and the Antihypertensive Drug Candesartan against Chronic Cerebral Ischemia in Rats

Chronic cerebral ischemia with a notable long-term cessation of blood supply to the brain tissues leads to sensorimotor defects and short- and long-term memory problems. Neuroprotective agents are used in an attempt to save ischemic neurons from necrosis and apoptosis, such as the antioxidant agent Eucalyptus. Numerous studies have demonstrated the involvement of the renin-angiotensin system in the initiation and progression of cardiovascular and neurodegenerative diseases. Candesartan is a drug that acts as an angiotensin II receptor 1 blocker. We established a rat model exhibiting sensorimotor and cognitive impairments due to chronic cerebral ischemia induced by the ligation of the right common carotid artery. Wistar male rats were randomly divided into five groups: Sham group, Untreated Ligated group, Ischemic group treated with Eucalyptus (500 mg/kg), Ischemic group treated with Candesartan (0.5 mg/kg), and Ischemic group treated with a combination of Eucalyptus and Candesartan. To evaluate the sensorimotor disorders, we performed the beam balance test, the beam walking test, and the modified sticky test. Moreover, the object recognition test and the Morris water maze test were performed to assess the memory disorders of the rats. The infarct rat brain regions were subsequently stained using the triphenyltetrazolium chloride staining technique. The rats in the Sham group had normal sensorimotor and cognitive functions without the appearance of microscopic ischemic brain lesions. In parallel, the untreated Ischemic group showed severe impaired neurological functions with the presence of considerable brain infarctions. The treatment of the Ischemic group with a combination of both Eucalyptus and Candesartan was more efficient in improving the sensorimotor and cognitive deficits (p < 0.001) than the treatment with Eucalyptus or Candesartan alone (p < 0.05), by the comparison to the non-treated Ischemic group. Our study shows that the combination of Eucalyptus and Candesartan could decrease ischemic brain injury and improve neurological outcomes.

18F-Fluorodeoxyglucose-Positron Emission Tomography Imaging Detects Response to Therapeutic Intervention and Plaque Vulnerability in a Murine Model of Advanced Atherosclerotic Disease-Brief Report

OBJECTIVE

This study sought to determine whether ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography could be applied to a murine model of advanced atherosclerotic plaque vulnerability to detect response to therapeutic intervention and changes in lesion stability. Approach and Results: To analyze plaques susceptible to rupture, we fed ApoE^-/- mice a high-fat diet and induced vulnerable lesions by cast placement over the carotid artery. After 9 weeks of treatment with orthogonal therapeutic agents (including lipid-lowering and proefferocytic therapies), we assessed vascular inflammation and several features of plaque vulnerability by ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography and histopathology, respectively. We observed that ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography had the capacity to resolve histopathologically proven changes in plaque stability after treatment. Moreover, mean target-to-background ratios correlated with multiple characteristics of lesion instability, including the corrected vulnerability index.

CONCLUSIONS

These results suggest that the application of noninvasive ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography to a murine model can allow for the identification of vulnerable atherosclerotic plaques and their response to therapeutic intervention. This approach may prove useful as a drug discovery and prioritization method.

Ginsenoside Rg1 prevents vascular intimal hyperplasia involved by SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in a rat balloon injury

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Mey. is a traditional tonic that has been used for thousands of years, and has positive effects on vascular diseases. Ginsenoside Rg1 (GS-Rg1) is one of the active ingredients of Panax ginseng C. A. Mey. and has been shown to have beneficial effects against ischemia/reperfusion injury. Our previously study has found that GS-Rg1 can mobilize bone marrow stem cells and inhibit vascular smooth muscle proliferation and phenotype transformation. However, pharmacological effects and mechanism of GS-Rg1 in inhibiting intimal hyperplasia is still unknown.

AIM OF THE STUDY

This study was aimed to investigate whether GS-Rg1 prevented vascular intimal hyperplasia, and the involvement of stromal cell-derived factor-1α (SDF-1α)/CXCR4, stem cell factor (SCF)/c-kit and fractalkine (FKN)/CX3CR1 axes.

MATERIALS AND METHODS

Rats were operated with carotid artery balloon injury. The treatment groups were injected with 4, 8 and 16 mg/kg of GS-Rg1 for 14 days. The degree of intimal hyperplasia was evaluated by histopathological examination. The expression of α-SMA (α-smooth muscle actin) and CD133 were detected by double-label immunofluorescence. Serum levels of SDF-1α, SCF and soluble FKN (sFKN) were detected by enzyme linked immunosorbent assay (ELISA). The protein expressions of SCF, SDF-1α and FKN, as well as the receptors c-kit, CXC chemokine receptor type 4 (CXCR4) and CX3C chemokine receptor type 1 (CX3CR1) were detected by immunochemistry.

RESULTS

GS-Rg1 reduced intimal hyperplasia by evidence of the values of NIA, the ratio of NIA/MA, and the ratio of NIA/IELA and the ratio of NIA/LA, especially in 16 mg/kg group. Furthermore, GS-Rg1 8 mg/kg group and 16 mg/kg group decreased the protein expressions of the SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in neointima, meanwhile GS-Rg1 8 mg/kg group and 16 mg/kg group also attenuated the expressions of SDF-1α, SCF and sFKN in serum. In addition, the expression of α-SMA and CD133 marked smooth muscle progenitor cells (SMPCs) was decreased after GS-Rg1 treatment.

CONCLUSIONS

GS-Rg1 has a positive effect on inhibiting vascular intimal hyperplasia, and the underlying mechanism is related to inhibitory expression of SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes.

Changes in carotid stiffness in patients with familial hypercholesterolemia treated with Evolocumab®: A prospective cohort study

BACKGROUND AND AIM

Protein convertase subtilisin kexin type 9 (PCSK-9) inhibitors demonstrated efficacy in cholesterol reduction and in the prevention of cardiovascular events. We evaluated changes in lipid profile and carotid stiffness in patients with familial hypercholesterolemia during 12 weeks of treatment with a PCSK-9 inhibitor, Evolocumab®.

METHODS AND RESULTS

Patients with familial hypercholesterolemia starting a treatment with Evolocumab® were included. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), small dense LDL (assessed by LDL score) and carotid stiffness were evaluated before starting treatment with Evolocumab® and during 12 weeks of treatment. Twenty-five subjects were enrolled (52% males, mean age 51.5 years). TC and LDL-C were reduced of 38% and 52%, respectively during treatment, with LDL score reduced of 46.1%. In parallel, carotid stiffness changed from 8.8 (IQR: 7.0-10.4) m/sec to 6.6 (IQR: 5.4-7.5) m/sec, corresponding to a median change of 21.4% (p < 0.001), with a significant increase in carotid distensibility (from 12.1, IQR: 8.73-19.3 kPA^-1 × 10^-3 at T₀ to 21.8, IQR: 16.6-31.8 kPA^-1 × 10^-3 at T12_w) corresponding to a median change of 62.8% (p < 0.001). A multivariate analysis showed that changes in LDL score were independently associated with changes in carotid stiffness (β = 0.429, p = 0.041).

CONCLUSION

Small dense LDL reduction, as assessed by LDL score, is associated with changes in carotid stiffness in patients with familial hypercholesterolemia treated with Evolocumab®.

Influence of Nanosilver on Endothelial Function and Vascular Reactivity of Isolated Rabbit Carotid Artery

There is paucity of information on the effects and mechanism of action of Nanosilver on vascular tone andendothelial function in spite of the upsurge in nanotechnology application in biomedicine. The present study determined theeffect of Nanosilver on vascular reactivity and endothelial function on isolated rabbit carotid artery in standard laboratory20 mL organ bath procedures containing physiological salt solution (PSS) bubbled with 95% O2, 5% CO2. Isometriccontractions were recorded electronically with a 4-channel Grass Polygraph and maintained at 37oC and pH7.4. Cumulativedose response tests to α-receptor agonist phenylephrine (PE) was examined separately, in normal PSS (control) and following20 minutes exposure to varying concentrations of Nanosilver solution [(NAgs) (1.25 and 2.50)] µg/mL in endothelium intact(+E) (control) and endothelium denuded (-E) rings. Contractile responses were analysed with reference to maximalcontractions induced by 8 x 10-2 M K+ in normal PSS. In another experiment, arterial rings were precontracted with EC70 MPE, high and /or low (8, 2 x 10-2) M K+PSS. At stable contractions, cumulative relaxation responses to NAgs was studied.Relaxation responses were analysed with reference to maximal contraction induced by EC70 M PE and/or K+ depolarizationin normal PSS. Following 20 minutes exposure to NAgs, dose relaxation response to acetylcholine (ACh) was also examinedin normal PSS (control), and pre-incubated L-NAME (NO synthase inhibitor) and indomethacin (cyclooxygenase inhibitor)precontracted arterial rings to further determine mechanisms of action. Data were presented as Means ± SEM. Graphs andstatistical analysis were done using GraphPad prism version 7.03 and Student t-test. P-values (P< 0.05) were consideredstatistically significant. The results showed that nanosilver decreased maximum contraction (Emax) and induced attenuatedcontractile and relaxation responses concentration-dependently in +E and -E carotid arterial rings. Also, Nanosilver-inducedrelaxation in α- receptor mediated contraction is endothelium-dependent and showed a biphasic dose-dependent response. Inconclusion, Nanosilver causes attenuation in carotid arterial smooth muscle reactivity with a biphasic dose-dependentrelaxant effect and multiple endothelium-dependent pathways mode of action.

Pituitary adenylate cyclase-activating polypeptide ameliorates vascular dysfunction induced by hyperglycaemia

BACKGROUND

Short-lasting hyperglycaemia occurs frequently in prediabetes and poorly controlled diabetes mellitus leading to vascular damage. Pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to play a protective role in vascular complications of diabetes; moreover, antioxidant effects of PACAP were also described. Therefore, we hypothesized that PACAP exerts protective effects in short-term hyperglycaemia-induced vascular dysfunctions.

METHODS

After short-term hyperglycaemia, acetylcholine-induced and sodium nitroprusside-induced vascular relaxation of mouse carotid arteries were tested with a myograph with or without the presence of PACAP or superoxide dismutase. Potential direct antioxidant superoxide-scavenging action of pituitary adenylate cyclase-activating peptide was tested with pyrogallol autoxidation assay; furthermore, the effect of pituitary adenylate cyclase-activating peptide or superoxide dismutase was investigated on hyperglycaemia-associated vascular markers.

RESULTS

PACAP administration resulted in reduced endothelial dysfunction after a 1-h hyperglycaemic episode. PACAP was able to restore acetylcholine-induced relaxation of the vessels and improved sodium nitroprusside-induced relaxation. This effect was comparable to the protective effect of superoxide dismutase, but PACAP was unable to directly scavenge superoxide produced by autoxidation of pyrogallol. Endothelial dysfunction was associated with elevated levels of fibroblast growth factor basic, matrix metalloproteinase 9 and nephroblastoma overexpressed gene proteins. Their release was reduced by PACAP administration.

CONCLUSION

These results suggest a strong protective role of PACAP in the vascular complications of diabetes.

Stepwise occlusion of the carotid arteries of the rat: MRI assessment of the effect of donepezil and hypoperfusion-induced brain atrophy and white matter microstructural changes

Bilateral common carotid artery occlusion (BCCAo) in the rat is a widely used animal model of vascular dementia and a valuable tool for preclinical pharmacological drug testing, although the varying degrees of acute focal ischemic lesions it induces could interfere with its translational value. Recently, a modification to the BCCAo model, the stepwise occlusion of the two carotid arteries, has been introduced. To acquire objective translatable measures, we used longitudinal multimodal magnetic resonance imaging (MRI) to assess the effects of semi-chronic (8 days) donepezil treatment in this model, with half of the Wistar rats receiving the treatment one week after the stepwise BCCAo. With an ultrahigh field MRI, we measured high-resolution anatomy, diffusion tensor imaging, cerebral blood flow measurements and functional MRI in response to whisker stimulation, to evaluate both the structural and functional effects of the donepezil treatment and stepwise BCCAo up to 5 weeks post-occlusion. While no large ischemic lesions were detected, atrophy in the striatum and in the neocortex, along with widespread white matter microstructural changes, were found. Donepezil ameliorated the transient drop in the somatosensory BOLD response in distant cortical areas, as detected 2 weeks after the occlusion but the drug had no effect on the long term structural changes. Our results demonstrate a measurable functional MRI effect of the donepezil treatment and the importance of diffusion MRI and voxel based morphometry (VBM) analysis in the translational evaluation of the rat BCCAo model.

N-oleoylethanolamide suppresses intimal hyperplasia after balloon injury in rats through AMPK/PPARα pathway

Vascular smooth muscle cell (VSMC) proliferation and migration are crucial events in the pathological course of restenosis after percutaneous coronary intervention (PCI). N-oleoylethanolamide (OEA) is a bioactive lipid amide released upon dietary fat digestion with many reported actions. However, the effect of OEA on restenosis after vascular injury remains unknown. Here, we investigated the effects of OEA on intimal hyperplasia after balloon injury in vivo, its effect on VSMC proliferation and migration induced by platelet-derived growth factor (PDGF) stimulation in vitro, and the underlying mechanism underlying these effects. The results showed that OEA-treated rats displayed a significant reduction in neointima formation after balloon injury. In cultured VSMCs, treatment with OEA decreased cell proliferation and migration induced by PDGF. OEA treatment both in vivo and in vitro led to an increase in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and peroxisome proliferator-activated receptor alpha (PPARα), and a decrease in proliferating cell nuclear antigen (PCNA) and cyclinD1 expression. Pharmacological inhibition of AMPK and PPARα reversed the suppressive effects of OEA on VSMC proliferation and migration, suggesting that the suppressive effect of OEA on VSMC proliferation and migration is mediated through the activation of AMPK and PPARα. In conclusion, our present study demonstrated that OEA attenuated neointima formation in response to balloon injury by suppressing SMC proliferation and migration through an AMPK and PPARα-dependent mechanism. Our data suggests that OEA may be a potential therapeutic agent for restenosis after PCI.

Embolic Stroke due to Carotidynia Potentially Associated with Moving Carotid Artery Caused by Swallowing

A 63-year-old woman with end-stage renal disease on maintenance hemodialysis discontinued her medication for rheumatoid arthritis with prednisolone and azathioprine. One month later, she was admitted because of consciousness disturbance and right hemiparesis. Diffusion-weighted brain magnetic resonance imaging (MRI) revealed multiple hyperintensities in her left frontal and parietal lobes. She also developed high fever and left neck pain. Carotid ultrasonography showed calcified plaque with vessel wall swelling at the bifurcation of the left common carotid artery (LCCA) and surrounding hypoechoic soft tissue. The tissue was identified as an isodense lesion on noncontrast computed tomography (CT) and as a high-intensity lesion on fat-saturated T2-weighted MRI. From her symptoms and radiological findings, she was diagnosed with carotidynia. Cervical MRI also showed that the LCCA was transposed to a retropharyngeal location, suggesting a moving carotid artery. Carotid ultrasonography revealed that the LCCA moved to and from the retropharyngeal position with swallowing and was thus being compressed by the hyoid bone. After corticosteroid therapy was initiated with 30 mg of prednisolone, her symptoms and radiological findings improved. To our knowledge, this is the first report of a case of cerebral embolism due to carotidynia. The repetitive compressions by the hyoid bone during swallowing were presumed to have provoked shear stress and inflammation of the carotid vessel wall, which was aggravated by discontinuation of steroid therapy in our case. These mechanical and inflammatory stresses might cause dysfunction of endothelial cells, hypercoagulation, platelet hyperaggregation, and vulnerability and rupture of carotid plaques, and may subsequently result in embolic strokes.

Evaluation of Neuroprotective Effect of Hibiscus sabdariffa Linn. Aqueous Extract Against Ischaemic-Reperfusion Insult by Bilateral Common Carotid Artery Occlusion in Adult Male Rats

Ischaemic brain injury continues to be devastating, causing social, medical and relationship disruption. Oxidativedamage has been reported to be one of the mechanisms for brain damage following ischaemic stroke. The antioxidant activityof Hibiscus sabdariffa L. was investigated for a possible protective effect against ischaemia-induced brain damage in rats.Adult male Wistar rats (n=35) were divided into five groups of 7 rats per group. Group 1 served as control was given tapwater; Group 2: 500 mg/kg daily of Hibiscus sabdariffa L. extract (HSE); Group 3: bilateral common carotid artery occlusion(BCCAO) for 30 minutes followed by reperfusion for 24 hours; Group 4: 500 mg/kg (HSE) before BCCAO; Group 5: 500mg/kg vitamin E before BCCAO. All administrations were oral and lasted 3 weeks. Behavioural studies namely: transitions,rearings, groomings and forelimb grip strength were carried out. Rats were thereafter euthanized and biochemical[malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)], histological andmorphological investigations were carried out on rat whole brain. Animals pretreated with HSE showed a significant (p<0.05)reduction in their body weight compared to the control group. BCCAO produced a significant (p<0.05) reduction in GSH,SOD and CAT while elevating MDA non-significantly. The HSE and Vitamin E pretreatment ameliorated these biochemicalalterations and also attenuated reactive changes in cortical neurons. BCCAO treatment increased grooming and forelimbstrength which both HSE and vitamin E pretreatment reversed. The results suggest that H. sabdariffa L and vitamin E were protective in acute cerebral ischaemia induced by bilateral common carotid artery occlusion in adult male rats.

Characterization of the Anticoagulant and Antithrombotic Properties of the Sphingosine 1-Phosphate Mimetic FTY720

Sphingosine 1-phosphate (S1P) is a highly active lysophospholipid implicated in various cardiocerebrovascular events such as coagulation, myocardial infarction and stroke. However, as the functional S1P receptor antagonist, whether the S1P mimetic FTY720 can modulate coagulation and/or thrombotic formation remains largely unknown. We investigated the effects of FTY720 on adenosine diphosphate (ADP)-induced platelet aggregation, coagulation parameters and thrombus formation in rats. Pretreatment with FTY720 (2.5 mg/kg) inhibited platelet aggregation induced by ADP, elongated the thrombin time and decreased the fibrinogen levels. However, FTY720 produced no significant effects on the arteriovenous bypass thrombus formation or the FeCl3-induced thrombus formation in the inferior vena cava and the common carotid artery. Our data suggest that FTY720 can exert an inhibitory effect on platelet aggregation and coagulation-related parameters. These characteristics of FTY720 could be useful as an adjunct in the treatment of ischemic diseases such as ischemic stroke and myocardial infarction.

Association between adjunctive metformin therapy in young type 1 diabetes patients with excess body fat and reduction of carotid intima-media thickness

INTRODUCTION    Lipoprotein-associated phospholipase A2 (Lp-PLA2) and cholesteryl ester lipase (CEL) may oxidize low-density lipoproteins (oxLDL). OBJECTIVES    The aim of the study was to determine the influence of metformin on the metabolism of atherogenic lipid fractions in relation to Lp-PLA2 and CEL levels, as well as assess consequent improvement in the intima-media thickness (IMT) of the common carotid artery in young type 1 diabetes patients with excess body fat. PATIENTS AND METHODS    It was an open-label randomized clinical trial that lasted 6 months. It included a total of 84 people with metabolic decompensation (glycated hemoglobin >7.5%, >58.5 mmol/mol) of diabetes. Adjunctive metformin therapy (in addition to insulin) was administered in 42 patients, and the remaining 42 patients received insulin alone. Glycated low-density lipoproteins (LDLs), oxLDL, Lp-PLA2, and CEL were assessed by commercially available enzyme-linked immunosorbent assay kits. Cartoid IMT was measured using the Carotid Analyser for Research tool. Biochemical analyses were performed using routine laboratory techniques. RESULTS    The reduction of mean carotid IMT was observed in young type 1 diabetic adults treated additionally with metformin (0.6 ±0.1 cm vs 0.53 ±0.1 cm; P = 0.002). This effect was probably due to weight reduction (90 ±16 kg vs 87 ±15 kg, P = 0.054) and the decrease in atherogenic glycated LDL levels (1.5 ±0.5 mg/dl vs 1.6 ±1.046 mg/dl, P = 0.006). No such correlations were observed in patients treated with insulin alone. Additionally, in patients receiving metformin, glycated LDL levels were inversely correlated with Lp-PLA2 levels (r = -0.31, P <0.05). CONCLUSIONS    Additional use of metformin in young type 1 diabetic patients with excess body fat leads to a significant reduction of mean IMT in the common carotid artery. Concentrations of CEL and Lp-PLA2 were significantly increased in both study arms despite improved glucose metabolism.

Pravastatin and Clopidogrel Combined Inhibit Intimal Hyperplasia in a Rat Carotid Endarterectomy Model

Intimal hyperplasia, resulting from a complex cascade of events involving platelets, leukocytes, and smooth muscle cells, may be inhibited by the HMG-CoA reductase inhibitor pravastatin, which demonstrates inhibition of platelet activity and leukocyte adhesion and may be associated with inhibition of vascular smooth muscle cell proliferation and migration. Clopidogrel, an adenosine diphosphate (ADP) receptor inhibitor, was shown to decrease platelet activity and aggregation but not intimal hyperplasia (IH). We postulated that the combination of both pravastatin and clopidogrel would significantly decrease IH in a rat carotid endarterectomy model. Male Sprague-Dawley rats (n = 18) divided by treatment regimen underwent treatment for 2 weeks both before and after an open carotid endarterectomy. Serum collected at the time of harvest was measured for C-reactive protein (CRP), platelet activity, and total serum cholesterol; carotid arteries were removed and processed for IH determination. Control rats (n = 7) received oral vehicle daily before and following endarterectomy. Pravastatin-alone rats (n = 6) received oral pravastatin (10 mg/kg/day) before and after endarterectomy. Pravastatin plus clopidogrel rats (n = 5) received oral pravastatin (10 mg/kg/day) plus a preendarterectomy bolus of oral clopidogrel (4.3 mg/kg) before endarterectomy and resumed pravastatin (10 mg/kg/day) plus oral clopidogrel (1 mg/kg/day) postendarterectomy. Pravastatin alone and pravastatin plus clopidogrel significantly decreased CRP compared to controls (120.2 ±11.2 and 134.1 ±9.9 vs 191.1 ±9.2 µg/mL, respectively p = 0.003 and p = 0.0024). CRP levels were not different between pravastatin alone and pravastatin plus clopidogrel (p = 0.35). Platelet activity was significantly decreased by pravastatin alone and pravastatin plus clopidogrel in comparison to controls (7.3 ±2.2 and 6.6 ±2.8 vs 19.2 ±6.1 platelet reactive units (PRU), respectively p = 0.048 and p = 0.045). No significant difference was noted in platelet activity between pravastatin alone and pravastatin plus clopidogrel (p = 0.89). Pravastatin plus clopidogrel significantly reduced serum cholesterol compared to control and pravastatin alone (84.0 ±6.6 vs 110.4 ±7.4 and 117.0 ±8.8 mg/dL, respectively p = 0.03 and p = 0.01). Pravastatin alone did not decrease serum cholesterol compared to controls (p = 0.54). IH was not reduced by pravastatin alone compared to controls (p = 0.61) but was significantly decreased by pravastatin plus clopidogrel in comparison to control and pravastatin alone (3.0 ±1.1 vs 46.3 ±13.7 and 37.4 ±14.6% luminal stenosis, respectively p = 0.01 and p = 0.05). Pravastatin plus clopidogrel significantly decreased CRP, platelet activity, total serum cholesterol, and IH while pravastatin alone decreased only CRP and platelet activity. Intimal hyperplasia reduction may therefore be dependent on other contributors, possibly growth factors, cytokines, and oxidative stress. The combination of pravastatin plus clopidogrel may have synergistic or even additional inhibitory effects on IH. Pravastatin plus clopidogrel was effective in decreasing IH in a rat carotid endarterectomy model and may prove a useful therapy for IH reduction in the clinical setting.

Rationale and design of a multicenter randomized study for evaluating vascular function under uric acid control using the xanthine oxidase inhibitor, febuxostat: the PRIZE study

BACKGROUND

Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces endothelial dysfunction and inflammatory reactions in vascular systems, leading to atherosclerosis. Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. We designed the PRIZE study to evaluate the effects of febuxostat on a surrogate marker of cardiovascular disease risk, ultrasonography-based intima-media thickness of the carotid artery in patients with hyperuricemia.

METHODS

The study is a multicenter, prospective, randomized, open-label and blinded-endpoint evaluation (PROBE) design. A total of 500 patients with asymptomatic hyperuricemia (uric acid >7.0 mg/dL) and carotid intima-media thickness ≥1.1 mm will be randomized centrally to receive either febuxostat (10-60 mg/day) or non-pharmacological treatment. Randomization is carried out using the dynamic allocation method stratified according to age (<65, ≥65 year), gender, presence or absence of diabetes mellitus, serum uric acid (<8.0, ≥8.0 mg/dL), and carotid intima-media thickness (<1.3, ≥1.3 mm). In addition to administering the study drug, we will also direct lifestyle modification in all participants, including advice on control of body weight, sleep, exercise and healthy diet. Carotid intima-media thickness will be evaluated using ultrasonography performed by skilled technicians at a central laboratory. Follow-up will be continued for 24 months. The primary endpoint is percentage change in mean intima-media thickness of the common carotid artery 24 months after baseline, measured by carotid ultrasound imaging.

CONCLUSIONS

PRIZE will be the first study to provide important data on the effects of febuxostat on atherosclerosis in patients with asymptomatic hyperuricemia. Trial Registration Unique trial Number, UMIN000012911 ( https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000015081&language=E ).

Changing characteristics of statin-related cIMT trials from 1988 to 2006

OBJECTIVES

Changes in cIMT have not been consistently correlated with cardiovascular risk reduction in clinical studies. The variability of carotid intima media thickness (cIMT) changes in published statin LDL-C-lowering studies in relation to various baseline and study characteristics was assessed.

METHODS

This was an exploratory analysis of study-level data pooled from statin-treatment arms of 13 studies conducted during 1988-2006. Baseline mean common carotid artery (CCA)/cIMT, maximum mean CCA/cIMT and LDL-C levels, and annualized cIMT changes were estimated for the overall studies, those conducted before/after 2000, and in risk-based subgroups. Potential relationships between prespecified covariates and cIMT changes were assessed.

RESULTS

Baseline mean CCA/cIMT and LDL-C levels were higher in the combined studies conducted before year 2000 (0.8521 mm) than after 2000 (0.7458 mm), and somewhat higher in study populations of patients with coronary heart disease risk and those with greater LDL-C reductions. Mean CCA/cIMT changes were also larger for the studies conducted before 2000 (-0.0119 mm/year) than after 2000 (-0.0013 mm/year). Notably, studies conducted before 2000 were of longer duration (≥ 2 years) than after 2000 (<2 years). Heterogeneity in cIMT change was attributed to baseline and study-design characteristics. Longer study duration and greater LDL-C reductions were significantly related to larger annualized cIMT changes. Maximum cIMT results were similar.

CONCLUSION

Baseline cIMT and LDL-C levels were lower, and cIMT changes were smaller in statin cIMT trials conducted after 2000 than those before 2000. These trends are consistent with increased treatment and control of high LDL-C levels over recent years in clinical practice, and may influence the results of cIMT studies.

Effects of Acute Systemic Hypoxia and Hypercapnia on Brain Damage in a Rat Model of Hypoxia-Ischemia

Therapeutic hypercapnia has the potential for neuroprotection after global cerebral ischemia. Here we further investigated the effects of different degrees of acute systemic hypoxia in combination with hypercapnia on brain damage in a rat model of hypoxia and ischemia. Adult wistar rats underwent unilateral common carotid artery (CCA) ligation for 60 min followed by ventilation with normoxic or systemic hypoxic gas containing 11%O2,13%O2,15%O2 and 18%O2 (targeted to PaO2 30-39 mmHg, 40-49 mmHg, 50-59 mmHg, and 60-69 mmHg, respectively) or systemic hypoxic gas containing 8% carbon dioxide (targeted to PaCO2 60-80 mmHg) for 180 min. The mean artery pressure (MAP), blood gas, and cerebral blood flow (CBF) were evaluated. The cortical vascular permeability and brain edema were examined. The ipsilateral cortex damage and the percentage of hippocampal apoptotic neurons were evaluated by Nissl staining and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) assay as well as flow cytometry, respectively. Immunofluorescence and western blotting were performed to determine aquaporin-4 (AQP4) expression. In rats treated with severe hypoxia (PaO2 < 50 mmHg), hypercapnia augmented the decline of MAP with cortical CBF and damaged blood-brain barrier permeability (p < 0.05). In contrast, in rats treated with mild to moderate hypoxia (PaO2 > 50 mmHg), hypercapnia protected against these pathophysiological changes. Moreover, hypercapnia treatment significantly reduced brain damage in the ischemic ipsilateral cortex and decreased the percentage of apoptotic neurons in the hippocampus after the CCA ligated rats were exposed to mild or moderate hypoxemia (PaO2 > 50 mmHg); especially under mild hypoxemia (PaO2 > 60 mmHg), hypercapnia significantly attenuated the expression of AQP4 protein with brain edema (p < 0.05). Hypercapnia exerts beneficial effects under mild to moderate hypoxemia and augments detrimental effects under severe hypoxemia on brain damage in a rat model of hypoxia-ischemia.

[INTRACRANIAL HEMODYNAMICS DURING ENDARTERECTOMY PERFORMING DUE TO STENOSIS OF THE CAROTID ARTERY: RESULTS OF INTRAOPERATIVE MONITORING]

Evaluation of intracranial hemodynamic parameters when performing endarterectomy over stenotic disease of carotid artery (CA) by Doppler intraoperative monitoring and the effectiveness of neuroprotection using Neoton during operative intervention. According to the results of research vessels duplex shoulder—main trunk in most patients after admission revealed bilateral heterogeneous plaques with predominance of hipoechogenous component were reveald. At the beginning of surgery in patients with marked increase in blood flow velocity in the middle cerebral artery — to (167.2 ± 1.3) cm/s, which is outside the permitted parameters. During bolus Neoton application pronounced changes of intracranial hemodynamics was no incidence, of cerebrovascular microemboli three times less. We discussed the feasibility of evaluating intracranial hemodynamics in patients with atherosclerotic lesions of arteries of shoulder—main trunk intraoperative stage.

G protein-coupled estrogen receptor inhibits vascular prostanoid production and activity

Complications of atherosclerotic vascular disease, such as myocardial infarction and stroke, are the most common causes of death in postmenopausal women. Endogenous estrogens inhibit vascular inflammation-driven atherogenesis, a process that involves cyclooxygenase (COX)-derived vasoconstrictor prostanoids such as thromboxane A2. Here, we studied whether the G protein-coupled estrogen receptor (GPER) mediates estrogen-dependent inhibitory effects on prostanoid production and activity under pro-inflammatory conditions. Effects of estrogen on production of thromboxane A(2) were determined in human endothelial cells stimulated by the pro-inflammatory cytokine tumour necrosis factor alpha (TNF-α). Moreover, Gper-deficient (Gper(-/-)) and WT mice were fed a pro-inflammatory diet and underwent ovariectomy or sham surgery to unmask the role of endogenous estrogens. Thereafter, contractions to acetylcholine-stimulated endothelial vasoconstrictor prostanoids and the thromboxane-prostanoid receptor agonist U46619 were recorded in isolated carotid arteries. In endothelial cells, TNF-α-stimulated thromboxane A2 production was inhibited by estrogen, an effect blocked by the GPER-selective antagonist G36. In ovary-intact mice, deletion of Gper increased prostanoid-dependent contractions by twofold. Ovariectomy also augmented prostanoid-dependent contractions by twofold in WT mice but had no additional effect in Gper(-/-) mice. These contractions were blocked by the COX inhibitor meclofenamate and unaffected by the nitric oxide synthase inhibitor l-N(G)-nitroarginine methyl ester. Vasoconstrictor responses to U46619 did not differ between groups, indicating intact signaling downstream of thromboxane-prostanoid receptor activation. In summary, under pro-inflammatory conditions, estrogen inhibits vasoconstrictor prostanoid production in endothelial cells and activity in intact arteries through GPER. Selective activation of GPER may therefore be considered as a novel strategy to treat increased prostanoid-dependent vasomotor tone or vascular disease in postmenopausal women.

Dihydroaustrasulfone alcohol inhibits PDGF-induced proliferation and migration of human aortic smooth muscle cells through inhibition of the cell cycle

Dihydroaustrasulfone alcohol is the synthetic precursor of austrasulfone, which is a marine natural product, isolated from the Taiwanese soft coral Cladiella australis. Dihydroaustrasulfone alcohol has anti-inflammatory, neuroprotective, antitumor and anti-atherogenic properties. Although dihydroaustrasulfone alcohol has been shown to inhibit neointima formation, its effect on human vascular smooth muscle cells (VSMCs) has not been elucidated. We examined the effects and the mechanisms of action of dihydroaustrasulfone alcohol on proliferation, migration and phenotypic modulation of human aortic smooth muscle cells (HASMCs). Dihydroaustrasulfone alcohol significantly inhibited proliferation, DNA synthesis and migration of HASMCs, without inducing cell death. Dihydroaustrasulfone alcohol also inhibited platelet-derived growth factor (PDGF)-induced expression of cyclin-dependent kinases (CDK) 2, CDK4, cyclin D1 and cyclin E. In addition, dihydroaustrasulfone alcohol inhibited PDGF-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), whereas it had no effect on the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/(Akt). Moreover, treatment with PD98059, a highly selective ERK inhibitor, blocked PDGF-induced upregulation of cyclin D1 and cyclin E and downregulation of p27^kip1. Furthermore, dihydroaustrasulfone alcohol also inhibits VSMC synthetic phenotype formation induced by PDGF. For in vivo studies, dihydroaustrasulfone alcohol decreased smooth muscle cell proliferation in a rat model of restenosis induced by balloon injury. Immunohistochemical staining showed that dihydroaustrasulfone alcohol noticeably decreased the expression of proliferating cell nuclear antigen (PCNA) and altered VSMC phenotype from a synthetic to contractile state. Our findings provide important insights into the mechanisms underlying the vasoprotective actions of dihydroaustrasulfone alcohol and suggest that it may be a useful therapeutic agent for the treatment of vascular occlusive disease.

Carbon Monoxide Releasing Molecule Accelerates Reendothelialization after Carotid Artery Balloon Injury in Rat

OBJECTIVE

This study was aimed to investigate the effects of carbon monoxide releasing molecule (CORM-2), a novel carbon monoxide carrier, on the reendothelialization of carotid artery in rat endothelial denudation model.

METHODS

Male rats subjected to carotid artery balloon injury were treated with CORM-2, inactive CORM-2 (iCORM-2) or dimethyl sulfoxide (DMSO). The reendothelialization capacity was evaluated by Evans Blue dye and the immunostaining with anti-CD31 antibody. The number of circulating endothelial progenitor cells (EPCs) was detected by flow cytometry. The proliferation, migration, and adhesion of human umbilical vein endothelial cells (HUVECs) were assessed by using [3H]thymidine, Boyden chamber and human fibronectin respectively. The expressions of protein were detected by using western blot analysis.

RESULTS

CORM-2 remarkably accelerated the re-endothelialization 5 d later and inhibited neointima formation 28 d later. In addition, the number of peripheral EPCs significantly increased in CORM-2-treated rats than that in iCORM-2 or DMSO-treated rats after 5 d later. In vitro experiments, CORM-2 significantly enhanced the proliferation, migration and adhesion of HUVECs. The levels of Akt, eNOS phosphorylation, and NO generation in HUVECs were also much higher in CORM-2 treated group. Blocking of PI3K/Akt/eNOS signaling pathway markedly suppressed the enhanced migration and adhesion of HUVECs induced by CORM-2.

CONCLUSION

CORM-2 could promote endothelial repair, and inhibit neointima formation after carotid artery balloon injury, which might be associated with the function changes of HUVECs regulated by PI3K/Akt/eNOS pathway.

Direct effect of incretin hormones on glucose and glycerol metabolism and hemodynamics

The objective of this study was to assess the insulin-independent effects of incretin hormones on glucose and glycerol metabolism and hemodynamics under euglycemic and hyperglycemic conditions. Young, healthy men (n=10) underwent three trials in a randomized, controlled, crossover study. Each trial consisted of a two-stage (euglycemia and hyperglycemia) pancreatic clamp (using somatostatin to prevent endogenous insulin secretion). Glucose and lipid metabolism was measured via infusion of stable glucose and glycerol isotopic tracers. Hemodynamic variables (femoral, brachial, and common carotid artery blood flow and flow-mediated dilation of the brachial artery) were also measured. The three trials differed as follows: 1) saline [control (CON)], 2) glucagon-like peptide (GLP-1, 0.5 pmol·kg(-1)·min(-1)), and 3) glucose-dependent insulinotropic polypeptide (GIP, 1.5 pmol·kg(-1)·min(-1)). No between-trial differences in glucose infusion rates (GIR) or glucose or glycerol kinetics were seen during euglycemia, whereas hyperglycemia resulted in increased GIR and glucose rate of disappearance during GLP-1 compared with CON and GIP (P<0.01 for all). However, when normalized to insulin levels, no differences between trials were seen for GIR or glucose rate of disappearance. Besides a higher femoral blood flow during hyperglycemia with GIP (vs. CON and GLP-1, P<0.001), no between-trial differences were seen for the hemodynamic variables. In conclusion, GLP-1 and GIP have no direct effect on whole body glucose metabolism or hemodynamics during euglycemia. On the contrary, during hyperglycemia, GIP increases femoral artery blood flow with no effect on glucose metabolism, whereas GLP-1 increases glucose disposal, potentially due to increased insulin levels.

Angiotensin II type 1 receptor blockers suppress neointimal hyperplasia after stent implantation in carotid arteries of hypercholesterolemic rabbits

OBJECTIVES

The purpose of this study was to examine whether oral administration of an angiotensin II type 1 receptor blocker (ARB) inhibited in-stent neointimal hyperplasia in carotid arteries of hypercholesterolemic rabbits.

METHODS

Eleven male New Zealand white rabbits were subjected to endothelial injuries of the right common carotid arteries using a balloon catheter and then received chow containing 1% cholesterol for 6 weeks. A balloon-expandable stainless steel stent was subsequently inserted at the injured sites of the arteries. After stenting, five rabbits were randomly treated with an oral ARB, candesartan cilexetil (5 mg/kg per day orally), while the remaining six rabbits acted as untreated controls. Four weeks after the implantation, the rabbits were killed, followed by collection of the arteries including the stents. After careful removal of the stents, tissue sections were prepared and analyzed by morphometric and immunohistochemical methods.

RESULTS

The mean thickness of the neointima was 53.6 ± 17.0 μm in the ARB-treated group, which was significantly reduced compared to 95.9 ± 16.7 μm in the control group (P = 0.0012). Immunohistochemistry showed a decrease in accumulation of macrophages and tenascin-C expression in the arterial wall in the ARB-treated animals.

DISCUSSION

This study suggested that systemic administration of an ARB suppressed neointimal hyperplasia in the carotid artery following stent implantation by the anti-inflammatory effects, although the animal cohort tested was rather small. This finding implies that ARBs may be useful and practical agents for protection against in-stent restenosis in humans, and warrants further basic and clinical studies.

Cardiometabolic and immune factors associated with increased common carotid artery intima-media thickness and cardiovascular disease in patients with systemic lupus erythematosus

BACKGROUND AND AIM

Patients with systemic lupus erythematosus (SLE) have a higher prevalence of subclinical atherosclerosis and higher risk of cardiovascular (CV) events compared to the general population. The relative contribution of CV-, immune- and disease-related risk factors to accelerated atherogenesis in SLE is unclear.

METHODS AND RESULTS

Fifty SLE patients with long-lasting disease (mean age 44 ± 10 years, 86% female) and 50 sex- and age-matched control subjects were studied. Common carotid artery intima-media thickness (CCA-IMT) was used as a surrogate marker of atherosclerosis. We evaluated traditional and immune- and disease-related factors, assessed multiple T-cell subsets by 10-parameter-eight-colour polychromatic flow cytometry and addressed the effect of pharmacological therapies on CCA-IMT. In SLE patients, among several cardiometabolic risk factors, only high-density lipoprotein levels (HDL) and their adenosine triphosphate-binding cassette transporter 1 (ABCA-1)-dependent cholesterol efflux capacity were markedly reduced (p < 0.01), whereas the CCA-IMT was significantly increased (p = 0.03) compared to controls. CCA-IMT correlated with systolic blood pressure, low-density lipoprotein (LDL) cholesterol and body mass index (BMI), but not with disease activity and duration. The activated CD4(+)HLA-DR(+) and CCR5(+) T-cell subsets were expanded in SLE patients. Patients under hydroxychloroquine (HCQ) therapy showed lower CCA-IMT (0.62 ± 0.08 vs. 0.68 ± 0.10 mm; p = 0.03) and better risk-factor profile and presented reduced circulating pro-atherogenic effector memory T-cell subsets and a parallel increased percentage of naïve T-cell subsets.

CONCLUSION

HDL represents the main metabolic parameter altered in SLE patients. The increased CCA-IMT in SLE patients may represent the net result of a process in which 'classic' CV risk factors give a continuous contribution, together with immunological factors (CD4(+)HLA-DR(+) T cells) which, on the contrary, could contribute through flares of activity of various degrees over time. Patients under HCQ therapy present a modified metabolic profile, a reduced T-cell activation associated with decreased subclinical atherosclerosis.

Mechanisms of vascular dysfunction in mice with endothelium-specific deletion of the PPAR-δ gene

Peroxisome proliferator-activated receptor (PPAR)-δ is a nuclear hormone receptor that is mainly involved in lipid metabolism. Recent studies have suggested that PPAR-δ agonists exert vascular protective effects. The present study was designed to characterize vascular function in mice with genetic inactivation of PPAR-δ in the endothelium. Mice with vascular endothelial cell-specific deletion of the PPAR-δ gene (ePPARδ(-/-) mice) were generated using loxP/Cre technology. ePPARδ(-/-) mice were normotensive and did not display any sign of metabolic syndrome. Endothelium-dependent relaxations to ACh and endothelium-independent relaxations to the nitric oxide (NO) donor diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate were both significantly impaired in the aorta and carotid arteries of ePPARδ(-/-) mice (P < 0.05). In ePPARδ(-/-) mouse aortas, phosphorylation of endothelial NO synthase at Ser(1177) was significantly decreased (P < 0.05). However, basal levels of cGMP were unexpectedly increased (P < 0.05). Enzymatic activity of GTP-cyclohydrolase I and tetrahydrobiopterin levels were also enhanced in ePPARδ(-/-) mice (P < 0.05). Most notably, endothelium-specific deletion of the PPAR-δ gene significantly decreased protein expressions of catalase and glutathione peroxidase 1 and resulted in increased levels of H2O2 in the aorta (P < 0.05). In contrast, superoxide anion production was unaltered. Moreover, treatment with catalase prevented the endothelial dysfunction and elevation of cGMP detected in aortas of ePPARδ(-/-) mice. The findings suggest that increased levels of cGMP caused by H2O2 impair vasodilator reactivity to endogenous and exogenous NO. We speculate that chronic elevation of H2O2 predisposes PPAR-δ-deficient arteries to oxidative stress and vascular dysfunction.

Hemocoagulase atrox reduces vascular modeling in rabbit carotid artery adventitia

OBJECTIVE

This study aimed to compare the effects of hemocoagulase atrox and cauterization hemostasis on intimal hyperplasia and explore the effect of hemocoagulase atrox on vascular modeling in rabbit carotid artery adventitia.

METHODS

A total of 27 rabbits were randomly divided into 3 groups (0d, 14d, 28d). They were anaesthetized using an intramuscular injection of phenobarbital sodium (1 ml/kg). The left and right common carotid arteries were exposed and capillary hemorrhaged after blunt dissection of the adventitia layers of common carotid arteries. Nine rabbits in each group were again randomly divided into 3 groups, in which animals were respectively treated with hemocoagulase (2 U/ml), cauterization (power = 40 w) and saline (as control). Groups of animals were euthanized at 0, 14 and 28 days after surgery. The samples were equally divided in the middle of the adventitia removal section to obtain equal parts for histologic, immunohistochemical and molecular biologic analysis. The vascular repair after adventitial stripping was observed by HE staining, Masson staining and transmission electron microscopy. The expression of carotid MCP-1, PCNA, TGF-β1, α-SMA and VEGF were measured at different time points by RT-PCR and immunohistochemical staining.

RESULTS

HE staining and Masson staining showed that hemocoagulase atrox had a significantly stronger effect on reducing intimal hyperplasia than the cauterization after 14 and 28 days. The results of RT-PCR showed that the expression of MCP-1, TGF-β1, α-SMA and VEGF in hemocoagulase atrox-treated animals were lower than that of cauterization-treated animals.

CONCLUSION

Our results suggested that hemocoagulase atrox as a topical hemostatic is safety and efficiently and it can accelerate adventitia restoration and decrease intimal proliferation.

Atherogenesis in youth--early consequence of adolescent smoking

BACKGROUND

Cigarette smoking is a prevalent risk behavior among adolescents and tracks into adulthood. Little is known on the early impact of smoking on the vasculature in adolescence, although smoking is considered highly atherogenic in adults. We investigated the association between active smoking and Carotid artery Intima Media Thickness (CIMT), an early indicator of atherosclerosis.

METHODS AND RESULTS

The SAPALDIA Youth Study is a nested study involving 356 offspring (8-20 yrs) of the Swiss SAPALDIA cohort who reported on early life, health and lifestyle, smoking habits and disease history. 288 youth underwent clinical examination. Mean average and maximum CIMT were calculated across all images of right and left common carotid. Multi-level linear regression was performed with weekly smoking, daily number of cigarettes and serum cotinine, adjusting for participant's and parental confounders. Valid CIMT data was available in 275 offspring (mean age 15 yrs, 53% girls). Weekly smoking was reported by 10% and current parental smoking by 24%. Individual mean and maximal CIMT averaged to 0.52 mm (sd 0.05) and 0.60 mm (sd. 0.05), respectively. Regression analyses yielded significant increase in average CIMT (mm) in weekly smokers (0.025, 95% CI 0.006; 0.045), per cigarette/day (0.003, 95% CI 0.001; 0.005) and serum cotinine level (0.008/100 μg/l, 95% CI 0.002; 0.015), which remained consistent after adjusting for parental confounders.

CONCLUSION

Our study yields evidence of an early adverse impact of active tobacco exposure on atherogenesis in adolescents, independent of parental smoking, underlining the public health importance of prevention of adolescent smoking.

The effects of angiotensin-converting enzyme-inhibitory peptide LAP on the left common carotid artery remodeling in spontaneously hypertensive rats

OBJECTIVE

To investigate the protective effect of angiotensin-converting enzyme (ACE)-inhibitory peptide LAP on the left common carotid artery remodeling in spontaneously hypertensive rats (SHRs).

METHODS

A cohort of male SHRs were randomly divided into three groups (n = 10 for each group): pseudo-experimental group, enalapril-treated group as a positive control group, ACE-inhibitory peptide LAP-treated group. After the experiment, the left common carotid artery from each rat was removed for morphological evaluation.

RESULTS

It was observed that the vascular medial thickness, media thickness/lumen diameter, medial cross-sectional area and mean nuclear area of smooth muscle cells of the left common carotid artery in the LAP group or enalapril group were significantly lower than those in the pseudo-experimental group, while there was no significant difference in these parameters observed between the LAP group and enalapril group. Additionally, the vascular area percentage of collagen fibers of the left common carotid artery in the LAP group and enalapril group was significantly lower than that of the pseudo-experimental group.

CONCLUSIONS

The protective vessel remodeling effect in SHRs was observed with ACE-inhibitory peptide LAP in SHRs by decreasing blood pressure, inhibiting smooth muscle cell hypertrophy and reducing the proliferation of collagen fibers.

Multi-ligand poly(L-lactic-co-glycolic acid) nanoparticles inhibit activation of endothelial cells

Endothelial cell (EC) activation and inflammation is a key step in the initiation and progression of many cardiovascular diseases. Targeted delivery of therapeutic reagents to inflamed EC using nanoparticles is challenging as nanoparticles do not arrest on EC efficiently under high shear stress. In this study, we developed a novel polymeric platelet-mimicking nanoparticle for strong particle adhesion onto ECs and enhanced particle internalization by ECs. This nanoparticle was encapsulated with dexamethasone as the anti-inflammatory drug, and conjugated with polyethylene glycol, glycoprotein 1b, and trans-activating transcriptional peptide. The multi-ligand nanoparticle showed significantly greater adhesion on P-selectin, von Willebrand Factor, than the unmodified particles, and activated EC in vitro under both static and flow conditions. Treatment of injured rat carotid arteries with these multi-ligand nanoparticles suppressed neointimal stenosis more than unconjugated nanoparticles did. These results indicate that this novel multi-ligand nanoparticle is efficient to target inflamed EC and inhibit inflammation and subsequent stenosis.

[Comparative analysis of action of beta-phenyl derivatives of glutamic and gamma-aminobutyric acid on cerebral blood flow and cerebrovascular endothelium after irreversible occlusion of the common carotid artery]

A comparative analysis of the effect of phenyl derivatives of glutamic (RGPU-135) and gamma-aminobutyric acid (Phenibut) on cerebral blood flow, vasodilatory endothelial function and the number of circulating endothelial cells desquamated in animals after irreversible occlusion of the common carotid arteries. It was found that animals treated prophylactically by RGPU-135, after occlusion of the common carotid arteries have higher cerebral blood flow and lower the severity of endothelial dysfunction than in animals treated with Phenibut.

Smooth muscle cell contraction increases the critical buckling pressure of arteries

Recent in vitro experiments demonstrated that arteries under increased internal pressure or decreased axial stretch may buckle into the tortuous pattern that is commonly observed in aging or diseased arteries in vivo. It suggests that buckling is a possible mechanism for the development of artery tortuosity. Vascular tone has significant effects on arterial mechanical properties but its effect on artery buckling is unknown. The objective of this study was to determine the effects of smooth muscle cell contraction on the critical buckling pressure of arteries. Porcine common carotid arteries were perfused in an ex vivo organ culture system overnight under physiological flow and pressure. The perfusion pressure was adjusted to determine the critical buckling pressure of these arteries at in vivo and reduced axial stretch ratios (1.5 and 1.3) at baseline and after smooth muscle contraction and relaxation stimulated by norepinephrine and sodium nitroprusside, respectively. Our results demonstrated that the critical buckling pressure was significantly higher when the smooth muscle was contracted compared with relaxed condition (97.3mmHg vs 72.9mmHg at axial stretch ratio of 1.3 and 93.7mmHg vs 58.6mmHg at 1.5, p<0.05). These results indicate that arterial smooth muscle cell contraction increased artery stability.

Complications of elastase-induced arterial saccular aneurysm in rabbits: case reports and literature review

Endoluminal infusion and incubation of elastase with or without collagenase into the rabbit common carotid artery is an established model of arterial saccular aneurysm. The model mimics naturally occurring human cerebral aneurysms in many ways, including histologic and morphologic characteristics, hemodynamic pressures, and shear stresses. However, complications have been associated with the model. Here, we report 2 complications: 1) the first known case of iatrogenic laryngeal hemiplegia in a rabbit; and 2) histopathologically confirmed iatrogenic hippocampal and cerebellar infarcts (stroke). Finally, we present and review data from current literature on the morbidity and mortality associated with this model.

Regulation of CCL5 expression in smooth muscle cells following arterial injury

Chemokines play a crucial role in inflammation and in the pathophysiology of atherosclerosis by recruiting inflammatory immune cells to the endothelium. Chemokine CCL5 has been shown to be involved in atherosclerosis progression. However, little is known about how CCL5 is regulated in vascular smooth muscle cells. In this study we report that CCL5 mRNA expression was induced and peaked in aorta at day 7 and then declined after balloon artery injury, whereas IP-10 and MCP-1 mRNA expression were induced and peaked at day 3 and then rapidly declined.

The expression of CCL5 receptors (CCR1, 3 & 5) were also rapidly induced and then declined except CCR5 which expression was still relatively high at day 14 after balloon injury. In rat smooth muscle cells (SMCs), similar as in aorta CCL5 mRNA expression was induced and kept increasing after LPS plus IFN-gamma stimulation, whereas IP-10 mRNA expression was rapidly induced and then declined. Our data further indicate that induction of CCL5 expression in SMCs was mediated by IRF-1 via binding to the IRF-1 response element in CCL5 promoter. Moreover, p38 MAPK was involved in suppression of CCL5 and IP-10 expression in SMCs through common upstream molecule MKK3. The downstream molecule MK2 was required for p38-mediated CCL5 but not IP-10 inhibition. Our findings indicate that CCL5 induction in aorta and SMCs is mediated by IRF-1 while activation of p38 MAPK signaling inhibits CCL5 and IP-10 expression. Methods targeting MK2 expression could be used to selectively regulate CCL5 but not IP-10 expression in SMCs.

Estrogen replacement attenuates exaggerated neointimal hyperplasia following carotid endarterectomy in rats

BACKGROUND

To investigate whether estrogen may attenuate neointima formation in hyperhomocysteinemic rat carotid endarterectomy.

METHODS

Rats were divided into 6 groups: ovariectomized estradiol-treated homocysteine or chow; ovariectomized placebo-treated homocysteine or chow; intact placebo-treated homocysteine or chow. Chow served as controls while homocysteine served as exaggerated intimal hyperplasia. Prior to endarterectomy, rats were implanted with estradiol mini-pump or placebo, diets given 2 weeks before and after surgery. Homocysteine, estrogen, and neointimal hyperplasia were determined.

RESULTS

Homocysteine was elevated in homocysteine groups versus controls except in estradiol-treated group. Intimal hyperplasia increased in placebo-treated ovariectomized homocysteine versus intact group. Exaggerated intimal hyperplasia in placebo-treated ovariectomized homocysteine was reduced by estrogen and so was homocysteine. Estrogen replacement in ovariectomized homocysteine group reduced intimal hyperplasia to that of intact or ovariectomized controls.

CONCLUSION

Estradiol treatment in this ovariectomized hyperhomocysteinemia carotid endarterectomy and resultant attenuation of homocysteine and neointima may have relevance to the beneficial effects of estrogen on hyperplastic response.

[Pretreatment of isolated vein with rapamycin nanoparticles inhibits vein graft stenosis in rabbits]

OBJECTIVE

To explore the effects of pretreatment of carbopol-encapsulated rapamycin-loaded nanoparticles (RPM-NP) on vein graft stenosis in a rabbit vein graft model.

METHODS

A segment of common carotid artery was replaced with a segment of external jugular vein in 40 rabbits. They were separated into four treatment groups, i.e. Group A: vein grafts were pretreated with intraluminal RPM-NP perfusion; Group B: peripheral venous veins were injected with RPM-NP; Group C: vein grafts received an equivalent perfusion of empty vehicle; Group D: vein grafts received no treatment. At Day 28 post-operation, the grafts and normal veins were harvested for histological examinations to analyze the indicators of intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index.

RESULTS

At Day 28 post-operation, the intimal/media thickness ratios were 0.26 ± 0.02, 0.73 ± 0.05, 0.71 ± 0.04, 0.69 ± 0.03 and 0.24 ± 0.01 in Groups A, B, C and D and the normal vein; the collagen volume index 0.24 ± 0.03, 0.56 ± 0.06, 0.53 ± 0.07, 0.49 ± 0.08 and 0.21 ± 0.01 respectively. Compared with the normal veins, the pathological indicators of vein graft intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index had significant differences in Groups B, C and D (all P < 0.05). But there were no significant differences among 3 groups (all P > 0.05). Compared with the normal vein, the parameters of vein graft intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index had no significant difference in Group A (all P > 0.05). But as compared with other groups, these indicators had statistical significant difference in Group A (all P < 0.05).

CONCLUSION

The local pretreatment of isolated vein with rapamycin nanoparticles may inhibit neointimal hyperplasia and prevent effectively vein graft stenosis.

Post-menopausal hormone therapy reduces autoantibodies to oxidized apolipoprotein B100

The aim of the study was to verify whether post-menopausal hormone replacement therapy (HRT) modifies autoantibody titers against oxidized low-density lipoprotein (LDL) (anti-LDLoxi), against epitopes of oxidized apolipoprotein B100 and common carotid intima-media thickness (IMT) in these women. Sixty-eight women in pre-menopause (PMW) and 216 in post-menopause (POMW) were recruited; eighty-three had undergone HRT for at least 12 months, where 48 received conjugated estrogens alone (EHRT) and 35 received conjugated estrogen and medroxyprogesterone acetate (CHRT). ELISA was used to determine autoantibodies. Lipoprotein lipase (LPL), hepatic lipase (HL), cholesterol ester transfer protein (CETP) and phospholipid transfer protein (PLTP) activities were assayed by radiometric methods. IMT was measured using Doppler ultrasound. Anti-oxidized LDL and anti-D antibodies increased by 40% (p ≤ 0.003) and 42% (p ≤ 0.006), respectively, with menopause. There was a surprising and significant 7% reduction in anti-D2 antibody titers with HRT (p ≤ 0.050), indicating a positive effect of treatment on the immune response to oxidized LDL. Combined HRT decreased activities of HL and LPL. HRT did not change common carotid IMT, which was increased by 32% as expected after menopause (p ≤ 0.030). This study describes, for the first time, the protective effect of HRT on decreasing autoantibody titers against oxidized apolipoprotein B in LDL.

Carotid plaque regression following 6-month statin therapy assessed by 3T cardiovascular magnetic resonance: comparison with ultrasound intima media thickness

BACKGROUND

Cardiovascular magnetic resonance (CMR) allows volumetric carotid plaque measurement that has advantage over 2-dimensional ultrasound (US) intima-media thickness (IMT) in evaluating treatment response. We tested the hypothesis that 6-month statin treatment in patients with carotid plaque will lead to plaque regression when measured by 3 Tesla CMR but not by IMT.

METHODS

Twenty-six subjects (67 ± 2 years, 7 females) with known carotid plaque (> 1.1 mm) and coronary or cerebrovascular atherosclerotic disease underwent 3T CMR (T1, T2, proton density and time of flight sequences) and US at baseline and following 6 months of statin therapy (6 had initiation, 7 had increase and 13 had maintenance of statin dosing). CMR plaque volume (PV) was measured in the region 12 mm below and up to 12 mm above carotid flow divider using software. Mean posterior IMT in the same region was measured. Baseline and 6-month CMR PV and US IMT were compared. Change in lipid rich/necrotic core (LR/NC) and calcification plaque components from CMR were related to change in PV.

RESULTS

Low-density lipoprotein cholesterol decreased (86 ± 6 to 74 ± 4 mg/dL, p = 0.046). CMR PV decreased 5.8 ± 2% (1036 ± 59 to 976 ± 65 mm3, p = 0.018). Mean IMT was unchanged (1.12 ± 0.06 vs. 1.14 ± 0.06 mm, p = NS). Patients with initiation or increase of statins had -8.8 ± 2.8% PV change (p = 0.001) while patients with maintenance of statin dosing had -2.7 ± 3% change in PV (p = NS). There was circumferential heterogeneity in CMR plaque thickness with greatest thickness in the posterior carotid artery, in the region opposite the flow divider. Similarly there was circumferential regional difference in change of plaque thickness with significant plaque regression in the anterior carotid region in region of the flow divider. Change in LR/NC (R = 0.62, p = 0.006) and calcification (R = 0.45, p = 0.03) correlated with PV change.

CONCLUSIONS

Six month statin therapy in patients with carotid plaque led to reduced plaque volume by 3T CMR, but ultrasound posterior IMT did not show any change. The heterogeneous spatial distribution of plaque and regional differences in magnitude of plaque regression may explain the difference in findings and support volumetric measurement of plaque. 3T CMR has potential advantage over ultrasound IMT to assess treatment response in individuals and may allow reduced sample size, duration and cost of clinical trials of plaque regression.

Evaluation of antioxidant and neuroprotective effect of date palm (Phoenix dactylifera L.) against bilateral common carotid artery occlusion in rats

The cerebral ischemia in rats was induced by occluding bilateral common carotid arteries (BCCAO) for 30 min., followed by 45 min reperfusion. BCCAO caused significant depletion in superoxide dismutase, catalase, glutathione, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and significant increase in lipid peroxidation along with severe neuronal damage in the brain. All the alterations except depletion in glutathione peroxidase and glutathione-S-transferase levels induced by cerebral ischemia were significantly attenuated by 15 days pretreatment with methanolic extract of P. dactylifera fruits (100, 300 mg/kg), whereas 30 mg/kg dose was insignificant in this regard. These results suggest the possible use P. dactylifera against bilateral common carotid artery occlusion induced oxidative stress and neuronal damage.

Tetrahydrobiopterin deficiency and nitric oxide synthase uncoupling contribute to atherosclerosis induced by disturbed flow

OBJECTIVE

Tetrahydrobiopterin (BH(4)) is a critical cofactor for nitric oxide (NO) synthesis by NO synthase (NOS). Recently, we demonstrated that disturbed flow produced by partial carotid ligation decreases BH(4) levels in vivo. We therefore aimed to determine whether atherosclerosis induced by disturbed flow is due to BH(4) deficiency and NOS uncoupling and whether increasing BH(4) would prevent endothelial dysfunction, plaque inflammation, and atherosclerosis.

METHODS AND RESULTS

We produced a region of disturbed flow in apolipoprotein E(-/-) mice using partial carotid ligation and fed these animals a high-fat diet. This caused endothelial NOS uncoupling as characterized by increased vascular superoxide production, altered vascular reactivity, and a change in endothelial NOS migration on low-temperature gel. These perturbations were accompanied by severe atherosclerosis, infiltration of T cells and macrophages, and an increase in cytokine production. Treatment with BH(4) recoupled NOS, decreased superoxide production, improved endothelium-dependent vasodilatation, and virtually eliminated atherosclerosis. BH(4) treatment also markedly reduced vascular inflammation and improved the cytokine milieu induced by disturbed flow.

CONCLUSIONS

Our results highlight a key role of BH(4) deficiency and NOS uncoupling in atherosclerosis induced by disturbed flow and provide insight into the effect of modulating vascular BH(4) levels on atherosclerosis and inflammation at these sites of the circulation.

Carotid intima media thickness, inflammatory markers, and endothelial activation markers in HIV Patients with lipoatrophy increased at 48 weeks regardless of use of rosiglitazone or placebo

Rosiglitazone may be useful for the treatment of antiretroviral therapy-associated lipoatrophy, but an association with cardiovascular disease (CVD) has been questioned in diabetics. We evaluated rosiglitazone's effect on surrogate markers of CVD in HIV-infected individuals with lipoatrophy. HIV(+) patients with lipoatrophy on thymidine-sparing regimens were randomized to rosiglitazone vs. placebo for 48 weeks. We serially assessed carotid IMT, fasting metabolic profiles, tumor necrosis factor (TNF)-α, soluble receptors (sTNFRI and II), interleukin (IL)-6, high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), and endothelial activation markers [von Willebrand factor (vWF), soluble intercellular cell adhesion molecules-1 (sICAM-1), and vascular cell adhesion molecules-1 (sVCAM-1)]. Seventy-one subjects enrolled: 17% were female and 51%were white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (p = 0.04). At 48 weeks, common carotid artery (CCA) IMT changed significantly (p ≤ 0.05) within but not between the groups (p = 0.36): the median (IQR) increase was 0.10 (0.05, 0.25) mm and 0.15 (0, 0.25) mm in the rosiglitazone and placebo groups, respectively. hsCRP, sTNFRI and II, sVCAM-1, and vWF changed significantly (p ≤ 0.02) within but not between groups. Total cholesterol increased significantly in the rosiglitazone group (p = 0.008). In our study of virologically controlled subjects with lipoatrophy, rosiglitazone did not independently increase carotid IMT, endothelial activation, and inflammatory cytokines.

[Cerebrovascular effects of GABA conjugate with arachidonic acid under conditions of separate and combined vascular pathology of brain and heart]

Experiments on rats showed that, under conditions of global transient ischemia, a conjugate of GABA with arachidonic acid enhances the local cerebral blood flow due to a decrease in the vascular tone. In intact rats, the examined neurolipin did not show unidirectional changes in the cerebral perfusion. Under conditions of experimental myocardial infarction and combined vascular pathology of brain and heart, the GABA conjugate with arachidonic acid increased the blood flow in the parietal region of brain cortex in most experiments, while decreasing the level of blood pressure.

Early hypercholesterolemia contributes to vasomotor dysfunction and injury associated atherogenesis that can be inhibited by nitric oxide

OBJECTIVE

Atherosclerosis results in vasomotor dysfunction, in part, through impairment of nitric oxide (NO) dependent vasodilation. It is unclear whether blood vessels are dysfunctional in an early environment of hypercholesterolemia alone and if this contributes to the vascular injury response. We hypothesize that early hypercholesterolemia, prior to gross vascular changes, contributes to vasomotor dysfunction and the vascular injury response. The efficacy of NO therapy to protect against the injury response in this setting was also assessed.

METHODS

The effect of oxidized low density lipoprotein (oxLDL) and inducible NO synthase (iNOS) gene transfer on rat aortic smooth muscle cell (SMC) proliferation was measured with (3)H-thymidine incorporation. Common carotid arteries (CCA) from wild-type C57BL6 (WT or C57) and apolipoprotein E deficient (ApoE KO) mice fed normal or Western diets for 6 to 8 weeks were tested for vasomotor function using an arteriograph system. Studies were repeated after CCA injury. The effect of iNOS gene transfer on morphometry by histology and vasomotor responses in injured CCAs in ApoE KO was examined.

RESULTS

OxLDL increased SMC proliferation by >50%. In SMC expressing iNOS, NO production was unaffected by oxLDL and reduced oxLDL and still inhibited SMC proliferation. Endothelium dependent vasorelaxation was reduced in uninjured CCAs from ApoE KO and C57 mice on the Western vs normal diet (ApoE 39% ± 2% vs 55% ± 13%; C57 50% ± 13% vs 76% ± 5%, P < .001) and was increased with longer durations of hypercholesterolemia. Endothelium-dependent and independent vasodilator responses were severely disrupted in C57 and ApoE KO mice 2 weeks following CCA injury but both recovered by 4 weeks. CCA injury in ApoE KO mice resulted in the formation of atheromatous lesions while C57 mice showed no change (intima 27,795 ± 1829 vs 237 ± 28 μm(2); media 46,306 ± 2448 vs 11,714 ± 392 μm(2), respectively; P < .001). This structural change in the ApoE KO reduced distensibility and increased stiffness. Finally, iNOS gene transfer to injured CCA in ApoE KO mice dramatically reduced atheromatous neointimal lesion formation.

CONCLUSIONS

Early hypercholesterolemia impairs endothelial function, with severity being related to duration and magnitude of hypercholesterolemia. Severe hypercholesterolemia leads to atheromatous lesion formation following injury and stresses the role of vascular injury in atherogenesis and suggests different mechanisms are involved in endothelial dysfunction and the injury response. Despite these changes, iNOS gene transfer still effectively inhibits atheroma formation. These findings support early correction of hypercholesterolemia and emphasize the potential role for NO based therapies in disease states.

Development of a new experimental model of saccular aneurysm by intra-arterial incubation of papain in rabbits

INTRODUCTION

Experimental saccular aneurysms can be created with surgical techniques of the arterial wall or by injecting pancreatic elastase. Papain is an enzyme with properties similar to those of elastase, and it has not been tested for this purpose. The objective of this study was to determine whether papain produces saccular aneurysms.

METHODS

Eleven New Zealand white rabbits (1.9-3.0 kg) were divided into two groups: group I (n = 8)-papain, and group II (n = 3)-sham. The animals underwent surgical exposure of the neck; the right common carotid artery was used as the test and the left common carotid artery as the control. On the 21st day after surgery, animals were sacrificed for removal of the arteries, measurements, and histological analysis. We determine formation of aneurysm to occur when the test artery dilated compared to the control.

RESULTS

There was no aneurysm formation in the sham group. The papain group showed aneurysm formation in all cases (100%). The average diameter of the aneurysms was 3.8  ± 1.4 mm and the average length was 16.7  ±  6.0 mm. The histological analysis showed a destruction of the elastic fibers in 100% of cases, mild inflammation in 62.5%, intimal fibrosis in 50%, endothelial injury in 100%, and thrombosis in 100% of cases.

CONCLUSION

Papain was capable of forming aneurysms with histological characteristics similar to those of elastase-induced aneurysms; however, a comparative study is necessary to determine whether the papain is superior to elastase in the production of experimental saccular aneurysms.

Evaluating endothelial function of the common carotid artery: an in vivo human model

BACKGROUND AND AIMS

Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV).

METHODS AND RESULTS

In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10 microg/m(2) bs and 300 microg of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001).

CONCLUSIONS

ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.

Methylmercury exposure and adverse cardiovascular effects in Faroese whaling men

BACKGROUND

Methylmercury (MeHg), a worldwide contaminant found in fish and seafood, has been linked to an increased risk of cardiovascular mortality.

OBJECTIVE

We examined 42 Faroese whaling men (30-70 years of age) to assess possible adverse effects within a wide range of MeHg exposures from consumption of pilot whale meat.

METHODS

We assessed exposure levels from mercury analysis of toenails and whole blood (obtained at the time of clinical examination), and a hair sample collected 7 years previously. Outcome measures included heart rate variability (HRV), blood pressure (BP), common carotid intima-media thickness (IMT), and brainstem auditory evoked potentials (BAEP). We carried out multiple regression and structural equation model (SEM) analyses to determine the confounder-adjusted effect of mercury exposure. Taking into account correlations among related measures, we categorized exposure and outcomes in groups to derive latent exposure and response variables in SEMs. We used multiple regression analysis to compare the predictive validity of individual exposure biomarkers and the latent exposure variable on individual and latent outcomes.

RESULTS

The toenail mercury concentrations varied widely and had a geometric mean of 2.0 microg/g; hair concentrations averaged about 3-fold higher. Mercury exposure was significantly associated with increased BP and IMT. This effect was reflected by SEMs, but mercury in toenails tended to be the best effect predictor.

CONCLUSIONS

The results support the notion that increased MeHg exposure promotes the development of cardiovascular disease.

Role of folic acid in atherosclerosis after kidney transplant: a double-blind, randomized, placebo-controlled clinical trial

OBJECTIVES

We investigated the effects of folic acid supplementation on plasma total homocysteine levels and carotid intima-media thickness after kidney transplant.

MATERIALS AND METHODS

Sixty patients who had undergone a kidney transplant were studied in this double-blind, randomized, placebo-controlled clinical trial. Those subjects were randomized to receive either 5 mg/d of oral folic acid or an equivalent dosage of placebo. The main outcome variables were the plasma total homocysteine level and carotid intima-media thickness (determined via B-mode sonography) at baseline and 2, 4, and 6 months after kidney transplant. We used independent and paired sample t tests for data analysis.

RESULTS

The mean age of the patients was 40.9 -/+ 10 years, and 32 of those subjects (58.2%) were men. In the control group, the plasma total homocysteine levels were 19 micromol/L at baseline, 18.7 micromol/L after 2 months, 19.3 micromol/L after 4 months, and 20 micromol/L after 6 months; and the carotid intima-media thickness measurements were 0.81 mm at baseline, 0.82 mm after 2 months, 0.84 mm after 4 months, and 0.85 mm after 6 months. In the folic acid group, the plasma total homocysteine levels were 18.5 micromol/L at baseline, 4.7 micromol/L after 2 months, 12.9 micromol/L after 4 months, and 10.9 micromol/L after 6 months; and the carotid intima-media thickness measurements were 0.73 mm at baseline, 0.73 mm after 2 months, 0.72 mm after 4 months, and 0.71 mm after 6 months.

CONCLUSIONS

Folic acid supplementation reduces both the plasma total homocysteine level and carotid intima-media thickness shortly after kidney transplant.

Regression of the increased common carotid artery-intima media thickness in subclinical hypothyroidism after thyroid hormone replacement

The association between subclinical hypothyroidism and cardiovascular disease and the beneficial effect of levothyroxine replacement in subclinical hypothyroidism are still under debate. The present study was designed to determine whether subclinical hypothyroidism is associated with an increase in the intima-media thickness of the common carotid artery (C-IMT) and whether thyroid hormone replacement can reverse this change in the C-IMT. Patients with newly-diagnosed subclinical (n=36) and overt (n=40) hypothyroidism and healthy euthyroid individuals (n=32) participated in this study. All the patients were examined for clinical characteristics, and the serum lipid levels and the C-IMT were measured. Patients with subclinical hypothyroidism had a C-IMT measurement after 18 months of levothyroxine replacement. There were meaningful differences in total cholesterol and LDL-cholesterol levels between patients with subclinical hypothyroidism and euthyroidism. The subjects with subclinical and overt hypothyroidism had a greater C-IMT compared with euthyroid controls (0.66+/- 0.10 and 0.70+/- 0.11 vs. 0.57+/- 0.08 mm, respectively; P < 0.05). After 12 months of euthyroidism, 28 of 36 patients with subclinical hypothyroidism completed the follow-up study. Thyroid hormone replacement significantly decreased the C-IMT (0.67+/- 0.11 to 0.60+/- 0.10 mm; P = 0.021) and improved the lipid profile. Based on multiple regression analysis, the decrement in LDL-cholesterol was independently associated with the regression of the C-IMT. Subclinical hypothyroidism was closely related to an increased C-IMT. Thyroid hormone replacement resulted in regression of the increased C-IMT, which was attributed to the improvement in the lipid profile.

Investigation of the vascular and pleiotropic effects of atorvastatin and pioglitazone in a population at high cardiovascular risk

We investigated the effect of atorvastatin monotherapy and combined treatment with atorvastatin and pioglitazone on intima-media thickness, vascular function and the cardiovascular risk profile. In all, 148 patients (76 male, 72 female; aged 61.4+/-6.5 years; body mass index [BMI] 29.2+/-4.1 kg/m2; mean +/- SD) with increased cardiovascular (CV) risk factors were randomised. Intima-media thickness (IMT), the augmentation index (Aix@75), the microvascular response to acetylcholine (LDF), lipid status, and plasma levels of intact proinsulin, adiponectin, interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9), sCD40L, P-selectin, tissue plasminogen activator (t-PA) and blood lipids were monitored over six months. Atorvastatin treatment, alone and in combination with pioglitazone, revealed a significant regression in IMT (0.923+/-0.013 to 0.874+/-0.012 mm and 0.921+/-0.015 to 0.882+/-0.015 mm; mean +/- SEM; p<0.05 respectively) and Aix@75 (27.3+/-1.2 to 25.9+/-1.4; and 25.6+/-1.4 to 24.8+/-1.7%; p<0.05). The endothelial response to acetylcholine as measured by laser Doppler fluximetry (LDF) improved during combined treatment (373+/-57 to 576+/-153 AU; p<0.05). Addition of pioglitazone to atorva-statin resulted in significant further effects on high-sensitivity C-reactive protein (hsCRP), t-PA, P-selectin, adiponectin, triglycerides and high-density lipoprotein (HDL) cholesterol (p<0.05 respectively). Atorvastatin significantly improved IMT and vascular elasticity. Co-administration of pioglitazone provided additional effects on endothelial function, lipid profile and laboratory markers of inflammation.