Preparation of a Single-Cell Suspension from Mouse Carotid Arteries for Single-Cell Sequencing

Carotid arteries are major blood vessels in the neck that supply blood and oxygen to the brain, but carotid stenosis occurs when carotid arteries are clogged by plaque. Revealing the cellular composition of the carotid artery at the single-cell level is essential for treating carotid atherosclerosis. However, there is no ready-to-use protocol for the preparation of single-cell suspensions from carotid arteries. To obtain a suitable protocol for the dissociation of normal carotid arteries at the single-cell level with less damage to cells, we designed a two-step digestion method by integrating the digestion process of collagenase/DNase and trypsin. Acridine orange/propidium iodide (AO/PI) dual-fluorescence counting was used to detect cell viability and concentration, and it was found that the single-cell suspension satisfied the requirements for single-cell sequencing, with the viability of cells over 85% and a high cell concentration. After single-cell data processing, a median of ~2500 transcripts per cell were detected in each carotid artery cell. Notably, a variety of cell types of the normal carotid artery, including vascular smooth muscle cells (VSMCs), fibroblasts, endothelial cells (ECs), and macrophages and dendritic cells (Mφ/DCs), were concurrently detectable. This protocol may be applied to prepare a single-cell suspension of blood vessels from other tissues with appropriate modifications.

Dexmedetomidine Stereotaxic Injection Alleviates Neuronal Loss Following Bilateral Common Carotid Artery Occlusion via Up-Regulation of BDNF Expression

BACKGROUND/AIM

Neurogenesis is an important process in the recovery from neurological damage caused by ischemic lesions. Endogenous neurogenesis is insufficient to restore neuronal damage following cerebral ischemia. Dexmedetomidine (DEX) exerts neuroprotective effects against cerebral ischemia and ischemia/reperfusion injury. DEX promotes neurogenesis, including neuronal proliferation and maturation in the hippocampus. In a previous study, we showed that early neurogenesis increased 3 days after bilateral common carotid artery occlusion (BCCAO). In this study, we investigated the effect of DEX on neurogenesis 3 days after BCCAO.

MATERIALS AND METHODS

Male Sprague-Dawley (SD) rats (7-8 weeks old) were used as a BCCAO model. Right and left common carotid arteries of the rats were occluded using 4-0 silk sutures. Two hours after surgery, an intracranial DEX injection was administered to rats that underwent surgery using a stereotaxic injector. Brains were obtained from control and BCCAO rats 3 days after surgery. Immunohistochemistry was performed on the cortex and dentate gyrus of the hippocampus using a NeuN antibody. Western blot was performed with HIF1α and brain-derived neurotrophic factor (BDNF) antibodies.

RESULTS

The number of mature neurons decreased 3 days after BCCAO, but DEX treatment alleviated neural loss in the parietal cortex and hippocampus. Up-regulation of BDNF was also observed after dexmedetomidine treatment.

CONCLUSION

Stereotaxic injection of dexmedetomidine alleviates neural loss following BCCAO by up-regulating BDNF expression.

DN200434 Inhibits Vascular Smooth Muscle Cell Proliferation and Prevents Neointima Formation in Mice after Carotid Artery Ligation

BACKGRUOUND

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs), which contributes to the development of occlusive vascular diseases, requires elevated mitochondrial oxidative phosphorylation to meet the increased requirements for energy and anabolic precursors. Therefore, therapeutic strategies based on blockade of mitochondrial oxidative phosphorylation are considered promising for treatment of occlusive vascular diseases. Here, we investigated whether DN200434, an orally available estrogen receptor-related gamma inverse agonist, inhibits proliferation and migration of VSMCs and neointima formation by suppressing mitochondrial oxidative phosphorylation.

METHODS

VSMCs were isolated from the thoracic aortas of 4-week-old Sprague-Dawley rats. Oxidative phosphorylation and the cell cycle were analyzed in fetal bovine serum (FBS)- or platelet-derived growth factor (PDGF)-stimulated VSMCs using a Seahorse XF-24 analyzer and flow cytometry, respectively. A model of neointimal hyperplasia was generated by ligating the left common carotid artery in male C57BL/6J mice.

RESULTS

DN200434 inhibited mitochondrial respiration and mammalian target of rapamycin complex 1 activity and consequently suppressed FBS- or PDGF-stimulated proliferation and migration of VSMCs and cell cycle progression. Furthermore, DN200434 reduced carotid artery ligation-induced neointima formation in mice.

CONCLUSION

Our data suggest that DN200434 is a therapeutic option to prevent the progression of atherosclerosis.

EXPRESSION OF SYNAPTOFYSIN AND VEGF IN THE SENSOMOTOR CORTEX DURING THE CAROTID ARTERY LIGATION, THE BRAIN ANTIGEN SENSITIZATION AND THEIR COMBINATIONS

OBJECTIVE

The aim: To study changes of the expression of synaptophysin (Syn) and vascular endothelial growth factor (VEGF) in neurons of the sensorimotor cortex (SMC) to reveal after unilateral ligation of the carotid artery, sensitization with brain antigen and their combination.

PATIENTS AND METHODS

Materials and methods: Experimental animals - Wistar rats (260-290 g). Experimental models: mobilization of the left common carotid artery, ligation of the indicated artery, sensitization with cerebral antigen, combination of sensitization with cerebral antigen and ligation of the carotid artery. Methods: immunohistochemistry, quantitative densitometric assessment.

RESULTS

Results: Dyscirculatory disorders of cerebral blood supply during unilateral mobilization or ligation of the common carotid artery, sensitization with cerebral antigen lead in rats to a transient decrease in synaptophysin expression and phase changes in VEGF expression in the SMC from the lesion side. These changes occur in the absence of morphological changes in the cerebral cortex.

CONCLUSION

Conclusions: The absence of morphological changes in the SMC in the short term (10-30 days) after minor trauma to the common carotid artery (separation from the bed and n.vagus) or its ligation is accompanied by a transient decrease in Syn expression and some increase in VEGF, which may reflect a violation of synaptic function and the general metabolic activity of neurons. Sensitization with a brain antigen, leading to an increase in the level of anti-brain antibodies and immune complexes in the blood of rats, can act as an independent damaging factor for the brain, and also potentiates and prolongs changes caused by impaired blood circulation.

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.

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.

Early life factors and their relevance to intima-media thickness of the common carotid artery in early adulthood

BACKGROUND

Early life factors may predispose an offspring to cardiovascular disease in later life; relevance of these associations may extend to ‟healthy" people in Western populations. We examined the prospective associations between early life factors and adult carotid intima-media thickness (IMT), a surrogate marker of atherosclerosis, in a healthy German population.

METHODS

We studied term participants (n = 265) of the DONALD Study, with bilateral sonographic measurements of IMT (4-8 measurements on both left and right carotid artery) at age 18-40 years and prospectively collected data on early life factors (maternal and paternal age at child birth, birth weight, gestational weight gain and full breastfeeding (>17weeks). Mean IMT values were averaged from mean values of both sides. Associations between early life factors and adult IMT were analyzed using multivariable linear regression models with adjustment for potential confounders.

RESULTS

Adult mean IMT was 0.56mm, SD 0.03, (range: 0.41 mm-0.78 mm). Maternal age at child birth was of relevance for adult IMT, which was sex specific: Advanced maternal age at child birth was associated with an increased adult IMT among female offspring only (β 0.03, SE 0.009 mm/decade, P = 0.003), this was not affected by adult waist circumference, BMI or blood pressure. Other early life factors were not relevant for IMT levels in males and females.

CONCLUSION

This study suggests that advanced maternal age at child birth is of prospective relevance for adult IMT levels in a healthy German population and this association may be of adverse relevance for females only.

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.

Acute administration of beta-caryophyllene prevents endocannabinoid system activation during transient common carotid artery occlusion and reperfusion

BACKGROUND

The transient global cerebral hypoperfusion/reperfusion achieved by induction of Bilateral Common Carotid Artery Occlusion followed by Reperfusion (BCCAO/R) has been shown to stimulate early molecular changes that can be easily traced in brain tissue and plasma, and that are indicative of the tissue physiological response to the reperfusion-induced oxidative stress and inflammation. The aim of the present study is to probe the possibility to prevent the molecular changes induced by the BCCAO/R with dietary natural compounds known to possess anti-inflammatory activity, such as the phytocannabinoid beta-caryophyllene (BCP).

METHODS

Two groups of adult Wistar rats were used, sham-operated and submitted to BCCAO/R. In both groups, 6 h before surgery, half of the rats were gavage-fed with a single dose of BCP (40 mg/per rat in 300 μl of sunflower oil as vehicle), while the second half were pre-treated with the vehicle alone. HPLC, Western Blot and immunohistochemistry were used to analyze cerebral cortex and plasma.

RESULTS

After BCCAO/R, BCP prevented the increase of lipoperoxides occurring in the vehicle-treated rats in both cerebral cortex and plasma. In the frontal cortex, BCP further prevented activation of the endocannabinoid system (ECS), spared the docosahexaenoic acid (DHA), appeared to prevent the increase of cyclooxygenase-2 and increased the peroxisome-proliferator activated receptor-alpha (PPAR-alpha) protein levels, while, in plasma, BCP induced the reduction of arachidonoylethanolamide (AEA) levels as compared to vehicle-treated rats.

CONCLUSIONS

Collectively, the pre-treatment with BCP, likely acting as agonist for CB2 and PPAR-alpha receptors, modulates in a beneficial way the ECS activation and the lipoperoxidation, taken as indicative of oxidative stress. Furthermore, our results support the evidence that BCP may be used as a dietary supplement to control the physiological response to the hypoperfusion/reperfusion-induced oxidative stress.

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.

Pilot assessment of a human extracellular matrix-based vascular graft in a rabbit model

BACKGROUND

Herein we describe a small-diameter vascular graft constructed from rolled human amniotic membrane (hAM), with in vitro evaluation and subsequent in vivo assessment of its mechanical and initial biologic viability in the early postimplantation period. This approach for graft construction allows customization of graft dimensions, with wide-ranging potential clinical applicability as a nonautologous, allogeneic, cell-free graft material.

METHODS

Acellular hAMs were rolled into layered conduits (3.2-mm diameter) that were bound with fibrin and lyophilized. Constructs were seeded with human smooth muscle cells and cultured under controlled arterial hemodynamic conditions in vitro. Additionally, the acellular hAM conduits were surgically implanted as arterial interposition grafts into the carotid arteries of immunocompetent rabbits.

RESULTS

On in vitro analysis, smooth muscle cells were shown to adhere to, proliferate within, and remodel the scaffold during a 4-week culture period. At the end of the culture period, there was histologic and biomechanical evidence of graft wall layer coalescence. In vivo analysis demonstrated graft patency after 4 weeks (n = 3), with no hyperacute rejection or thrombotic occlusion. Explants displayed histologic evidence of active cellular remodeling, with endogenous cell repopulation of the graft wall concurrent with degradation of initial graft material. Cells were shown to align circumferentially to resemble a vascular medial layer.

CONCLUSIONS

The vascular grafts were shown to provide a supportive scaffold allowing cellular infiltration and remodeling by host cell populations in vivo. By use of this approach, "off-the-shelf" vascular grafts can be created with specified diameters and wall thicknesses to satisfy specific anatomic requirements in diverse populations of patients.

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.

Reversing gene expression in cardiovascular target organs following chronic depression of the paraventricular nucleus of hypothalamus and rostral ventrolateral medulla in spontaneous hypertensive rats

BACKGROUND

Chronic overexpression of an inwardly rectifying potassium channel (hKir2.1) in the paraventricular nucleus of the hypothalamus (PVN) and in the rostral ventrolateral medulla (RVLM) to suppress neuronal excitability, resulted in a long term decrease of blood pressure and sympathetic output in spontaneously hypertensive rats (SHR).

OBJECTIVE

Evaluate gene expression in end-organs of SHR after a chronic overexpression of hKir2.1 channels in either the PVN or RVLM.

METHODS

mRNA levels of 16 genes known to be involved with blood pressure regulation were evaluated using RT-PCR in tissues from the heart, common carotid artery and kidney of SHR submitted to chronic depression of PVN and RVLM excitability using a lentiviral vector (LVhKir2.1).

RESULTS

In SHR hearts in which either the PVN or RVLM were injected with LVhKir2.1, there was a downregulation of angiotensin II receptor 1b (AT1), ATPase, Ca(2+)-transporter, troponin T2 and tropomyosin2 (only in RVLM) relative to the sham group. In the kidney of SHR with LVhKir2.1 injections in PVN and RVLM, angiotensinogen, angiotensin II receptor2 (AT2) and endothelin1 were all upregulated compared to sham. In the carotid artery, endothelin2, endothelin receptor A and B were up-regulated following LVhKir2.1 in to either the PVN or RVLM relative to sham.

CONCLUSION

Chronic overexpression of hKir2.1 channels in PVN and RVLM, promoted a BP decrease with up-regulation of angiotensinogen and AT2 genes expression in the kidney and down-regulation of AT1 in the heart of SHR. Thus, we demonstrate the potential efficacy of central manipulation to protect against end-organ damage in essential hypertension.

Placental growth factor deficiency is associated with impaired cerebral vascular development in mice

STUDY HYPOTHESIS

Placental growth factor (PGF) is expressed in the developing mouse brain and contributes to vascularization and vessel patterning.

STUDY FINDING

PGF is dynamically expressed in fetal mouse brain, particularly forebrain, and is essential for normal cerebrovascular development.

WHAT IS KNOWN ALREADY

PGF rises in maternal plasma over normal human and mouse pregnancy but is low in many women with the acute onset hypertensive syndrome, pre-eclampsia (PE). Little is known about the expression of PGF in the fetus during PE. Pgf  (-/-) mice appear normal but recently cerebral vascular defects were documented in adult Pgf  (-/-) mice.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Here, temporal-spatial expression of PGF is mapped in normal fetal mouse brains and cerebral vasculature development is compared between normal and congenic Pgf  (-/-) fetuses to assess the actions of PGF during cerebrovascular development. Pgf/PGF, Vegfa/VEGF, Vegf receptor (Vegfr)1 and Vegfr2 expression were examined in the brains of embryonic day (E)12.5, 14.5, 16.5 and 18.5 C57BL/6 (B6) mice using quantitative PCR and immunohistochemistry. The cerebral vasculature was compared between Pgf  (-/-) and B6 embryonic and adult brains using whole mount techniques. Vulnerability to cerebral ischemia was investigated using a left common carotid ligation assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Pgf/PGF and Vegfr1 are highly expressed in E12.5-14.5 forebrain relative to VEGF and Vegfr2. Vegfa/VEGF is relatively more abundant in hindbrain (HB). PGF and VEGF expression were similar in midbrain. Delayed HB vascularization was seen at E10.5 and 11.5 in Pgf  (-/-) brains. At E14.5, Pgf  (-/-) circle of Willis showed unilateral hypoplasia and fewer collateral vessels, defects that persisted post-natally. Functionally, adult Pgf  (-/-) mice experienced cerebral ischemia after left common carotid arterial occlusion while B6 mice did not.

LIMITATIONS, REASONS FOR CAUTION

Since Pgf  (-/-) mice were used, consequences of complete absence of maternal and fetal PGF were defined. Therefore, the effects of maternal versus fetal PGF deficiency on cerebrovascular development cannot be separated. However, as PGF was strongly expressed in the developing brain at all timepoints, we suggest that local PGF has a more important role than distant maternal or placental sources. Full PGF loss is not expected in PE pregnancies, predicting that the effects of PGF deficiency identified in this model will be more severe than any effects in PE-offspring.

WIDER IMPLICATIONS OF THE FINDINGS

These studies provoke the question of whether PGF expression is decreased and cerebral vascular maldevelopment occurs in fetuses who experience a preeclamptic gestation. These individuals have already been reported to have elevated risk for stroke and cognitive impairments.

LARGE SCALE DATA

N/A.

STUDY FUNDING AND COMPETING INTERESTS

This work was supported by awards from the Natural Sciences and Engineering Research Council, the Canada Research Chairs Program and the Canadian Foundation for Innovation to B.A.C. and by training awards from the Universidade Federal de Pernambuco and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil to R.L.L.; Queen's University to V.R.K. and the Canadian Institutes of Health Research to M.T.R. The work of P.C. is supported by the Belgian Science Policy BELSPO-IUAP7/03, Structural funding by the Flemish Government-Methusalem funding, and the Flemish Science Fund-FWO grants. There were no competing interests.

Vascular Repair by Circumferential Cell Therapy Using Magnetic Nanoparticles and Tailored Magnets

Cardiovascular disease is often caused by endothelial cell (EC) dysfunction and atherosclerotic plaque formation at predilection sites. Also surgical procedures of plaque removal cause irreversible damage to the EC layer, inducing impairment of vascular function and restenosis. In the current study we have examined a potentially curative approach by radially symmetric re-endothelialization of vessels after their mechanical denudation. For this purpose a combination of nanotechnology with gene and cell therapy was applied to site-specifically re-endothelialize and restore vascular function. We have used complexes of lentiviral vectors and magnetic nanoparticles (MNPs) to overexpress the vasoprotective gene endothelial nitric oxide synthase (eNOS) in ECs. The MNP-loaded and eNOS-overexpressing cells were magnetic, and by magnetic fields they could be positioned at the vascular wall in a radially symmetric fashion even under flow conditions. We demonstrate that the treated vessels displayed enhanced eNOS expression and activity. Moreover, isometric force measurements revealed that EC replacement with eNOS-overexpressing cells restored endothelial function after vascular injury in eNOS(-/-) mice ex and in vivo. Thus, the combination of MNP-based gene and cell therapy with custom-made magnetic fields enables circumferential re-endothelialization of vessels and improvement of vascular function.

Deficiency of P-selectin glycoprotein ligand-1 is protective against the prothrombotic effects of interleukin-1β

BACKGROUND

Proinflammatory cytokines are associated with cardiovascular diseases, including acute and recurrent myocardial infarction. However, the causal role of cytokines in thrombotic complications of atherosclerosis remains unclear. Interleukin-1β (IL-1β) is currently being targeted in a human clinical trial for the prevention of ischemic events.

OBJECTIVES

The purpose of the present study was to test the role of IL-1β in arterial thrombosis and a potential protective effect of P-selectin glycoprotein ligand-1 (Psgl-1) deficiency.

METHODS AND RESULTS

Wild-type and Psgl-1-deficient mice were treated with IL-1β and then subjected to carotid photochemical injury to induce thrombosis. IL-1β shortened the time to thrombosis in wild-type mice, while Psgl-1(-/-) mice were protected from the prothrombotic effects of IL-1β. A neutralizing antibody to Psgl-1 was also effective in protecting against the prothrombotic effects of IL-1β. The protective effect of Psgl-1 deficiency was associated with reduced plasma levels of soluble P-selectin and collagen-stimulated whole blood aggregation.

CONCLUSIONS

Our data demonstrate that Psgl-1 deficiency is protective against the prothrombotic effects of IL-1β and suggest that Psgl-1 inhibition may be a useful treatment strategy for targeting vascular thrombosis associated with enhanced inflammatory states.

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.

Gene expression levels of elastin and fibulin-5 according to differences between carotid plaque regions

AIM

The purpose of this study was to investigate the gene expression levels of elastin and fibulin-5 according to differences between carotid plaque regions and to correlate it with clinical features of plaque destabilization.

MATERIALS AND METHODS

The study included 44 endarterectomy specimens available from operated symptomatic carotid artery stenoses. The specimens were separated according to anatomic location: internal carotid artery (ICA), external carotid artery (ECA) and common carotid artery (CCA), and then stored in liquid nitrogen. The amounts of cDNA for elastin and fibulin-5 were determined by Quantitative real-time PCR (Q-RT-PCR). Target gene copy numbers were normalized using hypoxanthine-guanine phosphoribosyltransferase (HPRT1) gene. The delta-delta CT method was applied for relative quantification.

RESULTS

Q-RT-PCR data showed that relative fibulin-5 gene expression was increased in ICA plaque regions when compared to CCA regions but not reaching significance (p=0.061). At the same time, no differences were observed in elastin mRNA level between different anatomic plaque regions (p>0.05). Moreover, elastin and fibulin-5 mRNA expression and clinical parameters were compared in ICA plaques versus CCA and ECA regions, respectively. Up-regulation of elastin and fibulin-5 mRNA levels in ICA were strongly correlated with family history of cardiovascular disease when compared to CCA (p<0.05). Up-regulation of fibulin-5 in ICA was significantly associated with diabetes, and elevated triglycerides and very low density lipoprotein (VLDL) when compared to ECA (p<0.05).

CONCLUSION

The clinical significance is the differences between the proximal and distal regions of the lesion, associated with the ICA, CCA and ECA respectively, with increased fibulin-5 in the ICA region.

P2 purinergic receptor activation of neuronal nitric oxide synthase and guanylyl cyclase in the dorsal facial area of the medulla increases blood flow in the common carotid arteries of cats

In the dorsal facial area (DFA) of the medulla, an activation of either P2 purinergic receptor or nitric oxide synthase (NOS) results in the release of glutamate, leading to an increase in blood flow of the common carotid artery (CCA). It is not known whether activation of the P2 receptor by ATP may mediate activation of NOS/guanylyl cyclase to cause glutamate release and/or whether L-Arg (nitric oxide (NO) precursor) may also cause ATP release from any other neuron, to cause an increase in CCA flow. We demonstrated that microinjections of P2 receptor agonists (ATP, α,β-methylene ATP) or NO precursor (L-arginine) into the DFA increased CCA blood flow. The P2-induced CCA blood flow increase was dose-dependently reduced by pretreatment with NG-nitro-arginine methyl ester (L-NAME, a non-specific NOS inhibitor), 7-nitroindazole (7-NI, a relatively selective neuronal NOS inhibitor) or methylene blue (MB, a guanylyl cyclase inhibitor) but not by that with D-NAME (an isomer of L-NAME) or N5-(1-iminoethyl)-L-ornithine (L-NIO, a potent endothelial NOS inhibitor). Involvement of glutamate release in these responses were substantiated by microdialysis studies, in which perfusions of ATP into the DFA increased the glutamate concentration in dialysates, but co-perfusion of ATP with L-NAME or 7-NI did not. Nevertheless, the arginine-induced CCA blood flow increase was abolished by combined pretreatment of L-NAME and MB, but not affected by pretreatment with a selective P2 receptor antagonist, pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). In conclusion, ATP activation of the P2 receptor in the DFA induced activation of neuronal NOS/guanylyl cyclase, which causes glutamate release leading to an increase in CCA blood flow. However, arginine activation of neuronal NOS/guanylyl cyclase, which also caused glutamate release and CCA blood flow increase, did not induce activation of P2 receptors. These findings provide important information for drug design and/or developing therapeutic strategies for the diseases associated with CCA blood flow that supplies intra- and extra-cranial tissues.

Soy food consumption, cardiometabolic alterations and carotid intima-media thickness in Chinese adults

BACKGROUND AND AIM

The associations between soy food consumption, cardiometabolic disturbances and subclinical atherosclerosis remain controversial due to limited evidence. We examined the associations of habitual soy food consumption with cardiometabolic disturbances and carotid intima-media thickness (CIMT).

METHODS AND RESULTS

We included 2939 subjects (2135 women and 804 men) aged 50-75 years in this community-based cross-sectional study. Dietary data and other covariates were collected using interviewer-administered questionnaires. We determined CIMT in relation to each subject's common carotid artery, internal carotid artery, carotid bifurcation, blood lipids, glucose and urine acid, blood pressure and waist circumference. A logistic regression model was applied to estimate the odd ratios (ORs) and 95% confidence intervals (CIs), and linear regression was used to estimate the regression coefficient and 95% CIs. After adjusting for potential confounders, we found that greater consumption of soy protein (6.1 vs. 0.5 g/d) was inverse associated with the presence of elevated total cholesterol (TC), dyslipidemia, abdominal obesity and hyperuricemia in women, and with abdominal obesity in men, although no significant sex-soy interactions were observed (P: 0.145-0.985). The consumption of soy protein and isoflavones was inversely associated with the number of cardiometabolic disturbances among women, but not men. There were no significant associations of soy protein and isoflavones with CIMT thickening and other cardiometabolic disturbances.

CONCLUSION

Greater soy consumption was associated with a lower presence of elevated TC, dyslipidemia, hyperuricemia and less number of cardiometabolic disturbances components in women.

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.

[Cell surface adhesion molecules mediated stretch-induced HL-60 cell adhesion to mouse common carotid arteries]

OBJECTIVE

To compare the roles of vascular cell adhesion molecular-1 (VCAM-1) and P-selectin in stretch-induced HL-60 cell adhesion to mouse common carotid arteries.

METHODS

After the isolated mouse common carotid arteries were perfused with HL-60 cells, the unbound leukocytes were washed away and the number of adherent cells in every single field was counted under a microscope. We first observed the effect of stretch on HL-60 cell adhesion to the endothelium of arteries under different magnitudes of luminal hydrostatic pressure. Then, the roles of VCAM-1 and P-selectin in stretch-induced HL-60 cell adhesion to mouse common carotid arteries were compared by the pretreatment of neutralizing antibodies against VCAM-1, P-selectin or isotype-matched control antibody, respectively.

RESULTS

The increase in luminal hydrostatic pressure of carotid arteries led to the increase of the number of HL-60 adhesion cells, suggesting that stretch induced HL-60 cell adhesion in a magnitude-dependent manner. The pretreatment with the isotype-matched control antibody failed to induce a significant change of the number of HL-60 adhesion cells. In contrast, the pretreatment of both VCAM-1 and P-selectin neutralizing antibodies dramatically reduced the number of adherent leukocytes (P<0.05), although no statistical significance was observed between the two groups.

CONCLUSION

Stretch can induce HL-60 cell adhesion to carotid arteries in a magnitude-dependent manner. VCAM-1 and P-selectin play some roles in mechanical stretch-induced HL-60 cell adhesion to mouse common carotid arteries.

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.

A systematic comparison between 1-D and 3-D hemodynamics in compliant arterial models

We present a systematic comparison of computational hemodynamics in arteries between a one-dimensional (1-D) and a three-dimensional (3-D) formulation with deformable vessel walls. The simulations were performed using a series of idealized compliant arterial models representing the common carotid artery, thoracic aorta, aortic bifurcation, and full aorta from the arch to the iliac bifurcation. The formulations share identical inflow and outflow boundary conditions and have compatible material laws. We also present an iterative algorithm to select the parameters for the outflow boundary conditions by using the 1-D theory to achieve a desired systolic and diastolic pressure at a particular vessel. This 1-D/3-D framework can be used to efficiently determine material and boundary condition parameters for 3-D subject-specific arterial models with deformable vessel walls. Finally, we explore the impact of different anatomical features and hemodynamic conditions on the numerical predictions. The results show good agreement between the two formulations, especially during the diastolic phase of the cycle.

Construction of an integral formula of biological age for a healthy Chinese population using principle component analysis

BACKGROUND

Whereas chronological age (CA) cannot distinguish functional differences among individuals of the same age, the biological age (BA) may be used to reflect the functional state of the body. The purpose of this study was to construct an integral formula of the BA, by using principle component analysis (PCA).

METHODS

The vital organ function of 505 healthy individuals of Han origin (age 35-91 years) was examined. A total of 114 indicators of cardiovascular, pulmonary, and brain functions, and clinical, inflammatory, genetic, psychological, and life habit factors were assessed as candidate indicators of aging. Candidate indicators were submitted with CA to correlation and redundancy analyses. The PCA method was used to build an integral formula of the BA for the population.

RESULTS

Seven biomarkers were selected in accordance with a certain load standard. These biomarkers included the trail making test (TMT), pulse pressure (PP), mitral valve annulus ventricular septum of the peak velocity of early filling (MVES), minimum carotid artery intimal-medial thickness (IMTmin), maximum internal diameter of the carotid artery (Dmax), maximal midexpiratory flow rate 75/25 (MMEF75/25), and Cystatin C (CysC). The formula for the BA was: BA = 0.0685 (TMT) + 0.267 (PP) - 1.375 (MVES) + 22.443 (IMTmin) + 2.962 (Dmax) - 2.332 (MMEF75/25) + 16.104 (CysC) + 0.137 (CA) + 0.492.

CONCLUSION

Several genetic and lifestyle indicators were considered as candidate markers of aging. However, ultimately, only markers reflecting the function of the vital organs were included in the BA formula. This study represents a useful attempt to employ multiple indicators to build a comprehensive BA evaluation formula of aging populations.

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.

Severity dependent up-regulations of LOX-1 and MCP-1 in early sclerotic changes of common carotid arteries in spontaneously hypertensive rats

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) and monocyte chemoattractant protein-1 (MCP-1) are molecules involving in the initiation and progression of atherosclerosis. In order to examine a possible difference in LOX-1 and MCP-1 expressions depending on the severity of early stage of atherosclerosis, we investigated atherosclerotic changes by exposure to hypertension and hyperlipidemia in common carotid arteries (CCAs) of stroke-prone spontaneously hypertensive rat (SHR-SP). Three rat model groups such as control [Wistar Kyoto rat (WKY) group], hypertension (SHR-SP group) and hypertension + hyperlipidemia [SHR-SP + high fat and cholesterol (HFC) group] were used. Body weights, brain weights, systolic blood pressures and serum levels of total cholesterol, low-density lipoprotein and triglyceride were measured at 0, 5, 10 and 15 days after appropriate diet. Immunohistochemistry showed that the positive area and the strength of LOX-1 and MCP-1 were larger in the SHR-SP + HFC group than in the SHR-SP group, while no immunoreactivities were found in the WKY group. Conventional RT-PCR and real-time PCR analyses showed that mRNAs of those in the SHR-SP group were higher with greater up-regulation in the SHR-SP + HFC group. LOX-1 and MCP-1 expressions were coordinately up-regulated at mRNA and protein levels in an early stage of sclerosis depending on the severity of atherosclerotic stress. Activations of LOX-1 and MCP-1 are collectively involved in the early stage of atherosclerosis.

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.

Role of the phosphatase PTEN in early vascular remodeling

Background

The phosphatase PTEN represents an important physiological inhibitor of phosphatidylinositol-3 kinase (PI3-K)/protein kinase B (Akt) signalling, however, the functional role of PTEN in the initial phase of angioplasty-induced vascular injury remains elusive. In the present study we sought to determine PTEN's effect on vascular smooth muscle cell (VSMC) apoptosis following acute injury in vivo and in vitro.

Methods and Results

Immunohistochemistry indicated a faint basal expression and equal distribution of PTEN in uninjured rat carotid arteries. 12 h following balloon-injury, PTEN expression was strongly increased in apoptotic (TUNEL+) VSMC. In vitro, stimulation with serum or different growth factors or subjecting VSMC to cyclic stretch had no effect on PTEN expression, whereas stimulation with H₂O₂ robustly increased PTEN expression in a time- and dose-dependent manner. To evaluate the functional role of PTEN expression, human VSMC were transduced with WT-PTEN. Overexpression of PTEN increased the number of apoptotic VSMC (19.8%±4.4 vs. 5.6%±2.3; P<0.001) as determined by TUNEL assay. In contrast, siRNA-mediated knock-down of PTEN attenuated the basal as well as H₂O₂-induced apoptosis of VSMC. Mechanistically, overexpression of PTEN prevented serum-induced Akt-phosphorylation, whereas siRNA-mediated knock down of PTEN augmented Akt-activation. Moreover, co-transfection of PTEN and a constitutive active Akt mutant prevented PTEN-dependent augmentation of VSMC apoptosis, indicating, that PTEN regulates VSMC apoptosis by inhibition of Akt phosphorylation/activation.

Conclusion

By interfering with the PI3-K/Akt-dependent survival signalling, the oxidative stress-induced up regulation of PTEN in VSMC of injured arteries augments the sensitivity of VSMC to apoptotic stimuli in the early phase following vascular injury, augmenting the initial injury and cell loss of the injured vessel wall. Thus, these data add to our understanding of PTEN's role during vascular remodelling.

Relationship between carotid intima media thickness and helminth infections on Flores Island, Indonesia

Objective

To examine the association between helminth infections and atherosclerosis.

Background

Chronic helminth infection, which can lead to poor nutritional status and anti-inflammatory response, might protect against the development of atherosclerosis.

Methods

A cross-sectional study was performed in Flores, Indonesia, an area highly endemic for soil-transmitted helminths (STH). Stool samples from 675 participants aged 18–80 years were collected and screened for Trichuris trichiura by microscopy and for Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, and Strongyloides stercoralis by qPCR. We collected data on body mass index (BMI), waist to hip ratio (WHR), blood pressure, fasting blood glucose (FBG), lipid, high sensitive C-reactive protein (hs-CRP), total immunoglobulin-E (TIgE) and Escherichia coli lipopolysaccharide stimulated cytokines (tumor necrosis factor and interleukin-10). In a subset of 301 elderly adults (≥40 years of age) carotid intima media thickness (cIMT) was measured.

Results

Participants with any STH infection had lower BMI (kg/m2) (mean difference −0.66, 95%CI [−1.26, −0.06]), WHR (−0.01, [−0.02, −0.00]), total cholesterol (mmol/L) (−0.22, [−0.43, −0.01]) and LDL-cholesterol (mmol/L) (−0.20, [−0.39, −0.00]) than uninfected participants. After additional adjustment for BMI the association between helminth infection and total cholesterol (mean difference −0.17, 95%CI [−0.37, 0.03]) as well as LDL-cholesterol (−0.15, [−0.33, 0.04]) was less pronounced. BMI, WHR, and total cholesterol were negatively associated with number species of helminth co-infections. Participants with high TIgE, an indicator of exposure to helminths, had lower FBG, TC, and HDL. The association between TIgE and TC and HDL remained significant after adjustment with BMI. No clear association was found between STH infection or TIgE and mean cIMT.

Conclusions

This cross-sectional study presents evidence that helminth infections were negatively associated with risk factors for cardiovascular disease, an association at least partially mediated by an effect on BMI. The significance of this finding needs to be determined.

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.

[Atherosclerosis of the common carotid artery in aged patients with arterial hypertension: characteristics of lipid peroxidation homeostasis]

To study the peroxide homeostasis's features in atherosclerosis of common carotid artery, 75 patients suffering from an arterial hypertension in the age of 60-74 years (middle age 64.62 +/- 0.57 year) and 30 practically healthy persons of advanced age were examined. Thickness of common carotid artery, atherosclerotic plaques, parameters of lipid profile, peroxide oxidation of lipid, antioxidant system (catalase, SOD), general anti-oxidative activity of the serum were estimated.

Genetic variants at the 9p21 locus contribute to atherosclerosis through modulation of ANRIL and CDKN2A/B

Genome-wide association studies (GWAS) have identified genetic variants contributing to the risk of cardiovascular disease (CVD) at the chromosome 9p21 locus. The CVD-associated region is adjacent to the two cyclin dependent kinase inhibitors (CDKN)2A and 2B and the last exons of the non-coding RNA, ANRIL. It is still not clear which of or how these transcripts are involved in the pathogenesis of atherosclerosis.

OBJECTIVE

We assessed the hypothesis that 9p21 locus polymorphisms influence the expression of the transcripts in the region (ANRIL, CDKN2A/B) and that these transcripts contribute to atherogenesis through the modulation of proliferation in VSMC.

METHODS

We genotyped 18 SNPs (r(2)<0.8 and MAF>0.05) across the region of interest: CDKN2A/B and ANRIL, encompassing the CVD-associated region. RNA and DNA were extracted from the blood of 57 volunteers (69-72 years old). Carotid ultrasound was performed in 56 subjects. CDKN2A/B and ANRIL (exons 1-2 and 17-18) expression was measured employing RT-PCR. Gene expression and cell growth were evaluated in cultured VSMC after the siRNA-mediated knock-down of ANRIL.

RESULTS

The risk alleles for atherosclerosis-related phenotypes were consistently associated with a lower expression of ANRIL when evaluating exons 1-2. Common carotid artery stenosis was associated with a significantly lower (P<0.01) expression of ANRIL (exons 1-2). ANRIL knock-down in VSMC caused significant variation in expression of CDKN2A/B (P<0.05) and reduction of cell growth (P<0.05) in vitro.

CONCLUSION

Disease-associated SNPs at the 9p21 locus predominantly affect the expression of ANRIL. Overall, our results suggest that several CVD-associated SNPs in the 9p21 locus affect the expression of ANRIL, which, in turn modulate cell growth, possibly via CDKN2A/B regulation.

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.

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.

Relationship between thrombin generation and carotid intima-media thickness

Increasing evidence indicates that thrombin plays a role not only in thrombosis but also in the progression of atherosclerosis.

AIM

The relationship between thrombin generation and intima-media thickness (IMT) as an index of subclinical atherosclerosis was investigated. Participants, material, methods: We examined 163 asymptomatic middle-aged persons free of overt clinical atherosclerotic disease. They underwent ultrasonography of the common carotid arteries. In addition, thrombin generation was measured by means of CAT (calibrated automated thrombography). For our study we divided the healthy study participants into three age groups (<45, 45-60 and >60 years).

RESULTS

A significant positive correlation was seen between endogenous thrombin potential (ETP) (p = 0.012), time to peak (TTP) (p = 0.033) start tail (p = 0.007) and carotid IMT in the group of healthy volunteers younger than 45 years.

CONCLUSION

We demonstrated that in adults younger than 45 years without clinically overt atherosclerotic disease ETP was significantly associated with carotid IMT. It is tempting to speculate that ETP may serve as an index for subclinical atherosclerosis in persons below 45 years.

[The source and factors that influence tracheal pulse oximetry signal]

OBJECTIVE

To investigate the source and factors that influence tracheal pulse oximetry signal.

METHODS

The adult mongrel dog was intubated after anesthesia. The tracheal tube was modified by attaching a disposable pediatric pulse oximeter to the cuff. The chest of the dog was cut open and a red light from the tracheal oximeter was aligned with the deeper artery. The changes in tracheal pulse oxygen saturation (SptO2) signal were observed after the deeper artery was blocked temporarily. The photoplethysmography (PPG) and readings were recorded at different intracuff pressures. The influence of mechanical ventilation on the signal was also tested and compared with pulse oxygen saturation (SpO2).

RESULTS

The SptO2 signal disappeared after deeper artery was blocked. The SptO2 signal changed with different intracuff pressures (P < 0.001). Stronger SptO2 signal appeared under 20-60 cm H2O of intracuff pressure than under 0-10 cm H2O of intracuff pressure(P < 0.001). The PPG of SptO2 signal under a condition with mechanical ventilation differed from that without mechanical ventilation (P < 0. 01), which, was also different from SpO2 (P < 0.01).

CONCLUSION

SptO2 signal is primarily derived from deeper arteries around the trachea, not from the tracheal wall. Both intracuff pressures and mechanical ventilation can influence SptO2 signal. The SptO2 signal under 20-60 cm H2O of intracuff pressure is stronger than that under 0-10 em H2O of intracuff pressure. Mechanical ventilation mainly changes PPG.

Mannose binding lectin gene polymorphism and preclinical carotid atherosclerosis in patients with systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) have increased risk of atherosclerosis and CVD that cannot be explained by traditional risk factors. Previous studies indicated that mannose binding lectin (MBL) may modify the development of atherosclerosis. This study was designed to investigate association of MBL gene polymorphism with occurrence of preclinical atherosclerosis in SLE. The study included 46 patients with SLE and 17 age and sex matched controls. MBL2 genotypes were assessed in patients and controls by the PCR-RFLP method and intima-media thickness of the common carotid artery (cclMT) was determined by means of ultrasonography. Also, serological markers were measured and the disease activity index (SLEDAI) was estimated. SLE patients had higher frequency of MBL A/B + B/B genotypes (47.8%) than controls (29.4%). ccIMT was higher in patients having A/B, B/B, A/B+B/B genotypes when compared with wild genotype (A/A). Patients with A/B+B/B genotypes showed high serum level of LDL, TG, ESRI, CRP and SLEDAI score, but low level of HDL, C3, and C4 compared to wild genotype. ccIMT of mutant SLE subgroup correlated well with SLE risk factors for atherosclerosis. In conclusion, mutant genotypes of MBL may be atherogenic as SLE patients had a higher IMT, which correlated significantly with SLE risk factors for atherosclerosis.

[Effect of Dahuang Zhechong pills on arterial thrombosis in rabbits]

OBJECTIVE

To investigate the effect of Dahuang Zhechong pills (DZ) on arterial thrombotic model in vivo.

METHODS

Sixty-five rabbits were randomly divided into 7 groups: normal, model (collagen encapsulated thread-drawing),model+aspirin (ASA), model+clopidogrel (CP),model+ASA+CP, model+ low dosage DZ (DZL), and model+high dosage DZ (DZH). All rabbits except the normal group were fed with the drugs repectively for 8 days,and sacrificed at 2 hours after the last feeding, obtained aortae. The pathological changes in the aortae were observed under microscope,and the level of FDP, D-dimer and tissue factor (TF) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The vascular vessels were filled with thrombi in the model group and the elastic membranes of the vessel wall were seriously injured. The arterial thrombi were observed around the vascular wall in the DZL group, but some of the thrombi were dissolved. The number of thrombi was remarkably decreased in the DZH group, and most thrombi were dissolved and the vascular intimal membranes were intact. Compared with the model group, the dry and wet weight of the thrombi and the level of D-dimer, FDP, and TF in the plasma were significantly attenuated (P<0.01) in all the treatment groups. There were no significant difference between the DZL group and the ASA group in the dry weight, D-Dimer, and FDP (P>0.05). The pathological changes in the vascular vessel and the elevation of plasma parameters in the DZL group were similar to those in the ASA and CP groups (P>0.05). The dry and wet weight, D-dimer, FDP, and TF in the plasma in the DZH group were significantly lower than those in the DZL group (P<0.01 or P<0.05, separatively), and closed to those in the ASA+CP group.

CONCLUSION

Dahuang Zhechong pills are potential novel anti-thromobotic agent for arterial thrombosis.

Inflammation status of rabbit carotid artery model endothelium during intermittent hypoxia exposure and its relationship with leptin

OBJECTIVES

To develop an intermittent hypoxia/reoxygenation (IH/ROX) rabbit carotid artery model and then investigate the inflammation status of rabbit carotid artery endothelium after IH exposure and its relationship with leptin.

MATERIALS AND METHODS

After anesthetization, rabbit's right common carotid artery was cleared of surrounding tissue with anatomic microscope, cannulated to its distal part and the proximal part was ligated. Preparations were challenged by changing the PO(2) of the gas mixture equilibrating the perfusate. Alternate perfusing (2 mL/min) of equilibrated perfusate bubbled with normoxia or hypoxia gas mixtures formed IH/ROX cycles in the right carotid common artery, simulating the pattern of hypoxic episodes seen in obstructive sleep apnea (OSA), or continuous perfusing of hypoxia perfusate to form continuous hypoxia (CH) modes. Sixty adult male New Zealand White rabbits (2.5-3.0 kg) were separated into six groups, ten per group. Groups were: A, intermittent normoxia (IN) group, perfused with perfusion equilibrated with 21% O(2) [PO(2) about 141 +/- 2.87 mmHg] for 15 s and 21% O(2) for 1 min 45 s, 60 cycles; B, severe IH group, 5% O(2) [PO(2) about 35.2 +/- 1.27 mmHg] 15 s and 21% O(2) 1 min 45 s, 60 cycles; C, mild IH group, 10% O(2) [PO(2) about 54.3 +/- 3.31 mmHg] 15 s and 21% O(2) 1 min 45 s, 60 cycles; D, severe IH+Lep group, protocol was the same with severe IH group; E, CH group, IN for 1 h 45 min and then 5% O(2) for 15 min; and F, Lep group, the same with IN group. Right common carotid artery parts distal to the cannula were harvested after exposure, and endothelial cell layers were gotten from longitudinal outspread vessels. Nuclear factor kappaB (NFkappaB) DNA binding activities of partial cell layers were measured with electrophoretic mobility shift assay in the IN group, severe IH group, mild IH group, and CH group nuclear extracts. The other part of the cell layers in the IN group, severe IH group, severe IH+Lep group, and Lep group were cultured for 2 h, and during the culture procedure, recombinated human leptin solutions were added to culture dishes of severe IH+Lep group and Lep group (resulted concentration, 10 ng/mL). Enzyme-linked immunosorbent assay was used to analyze medium interleukin-6 (IL-6) concentrations, reverse transcription polymerase chain reaction was used to analyze endothelial cell Ras homology A (RhoA) mRNA expression levels. Statistical analysis was done with SPSS 11.5 software package.

RESULTS

NFkappaB DNA binding activities were significantly different between groups (F = 112.428, P < 0.001). This activity in the severe IH group (4.27 +/- 0.64) was higher than that in the mild IH group (2.33 +/- 0.45, P < 0.001), IN group (1.00 +/- 0.26, P < 0.001), and CH group (1.15 +/- 0.36, P < 0.001). RhoA mRNA expression levels were different in groups (F = 26.634, P < 0.001).This level in the severe IH+Lep group (2.54 +/- 0.53) was higher than that in the severe IH group (1.57 +/- 0.44, P = 0.002), IN group (1.00 +/- 0.31, P < 0.001), and Lep group (1.31 +/- 0.30, P < 0.001). IL-6 concentrations were different in groups (F = 79.922, P < 0.001). IL-6 concentration in the severe IH+Lep group (1591.50 +/- 179.57 pg/mL) was higher than that in the severe IH group (1217.20 +/- 320.62 pg/mL, P = 0.036), IN group (325.40 +/- 85.26 pg/mL, P < 0.001), and Lep group (517.40 +/- 183.09 pg/mL, P < 0.001).

CONCLUSIONS

IH/ROX activated the inflammation pathway significantly in the endothelium, which was more intensive than CH and intensity-dependent. When exposed to both IH/ROX and leptin, inflammation occurs more dramatically. It means that synergic activating roles were performed by IH/ROX and leptin. This study may have a clinical implication that IH can cause endothelial damage through activated inflammation in OSA patients, and if the OSA patients have obesity at the same time, the endothelial damage or the inflammation would be more significant because of elevated leptin level as a synergic factor.

Syndecan-1: an inhibitor of arterial smooth muscle cell growth and intimal hyperplasia

OBJECTIVE

Arterial injury induces smooth muscle cell (SMC) proliferation, migration, and intimal accumulation of cells and extracellular matrix. These processes are regulated by the administration of the glycosaminoglycans heparin and heparan sulfate, but little is known about the role of endogenous heparan sulfate proteoglycans in the vessel wall. We investigated the response to carotid injury of syndecan-1-null mice to assess the function of one of a conserved family of transmembrane heparan and chondroitin sulfate proteoglycans.

METHODS AND RESULTS

Syndecan-1-null mice developed a large neointimal lesion after injury, whereas wild-type mice made little or none. This was accompanied by a significant increase in both medial and intimal SMC replication. Cultured syndecan-1-null SMCs showed a significant increase in proliferation in response to PDGF-BB, thrombin, FGF2, EGF, and serum. In response to thrombin, PDGF-BB, and serum syndecan-1-null SMCs expressed more PDGF-B chain message than did wild-type SMCs. Downregulation of PDGF-BB or PDGFRbeta inhibited thrombin-, PDGF-BB-, and serum-induced DNA synthesis in syndecan-1-null SMCs.

CONCLUSIONS

These results suggest the possibility that syndecan-1 may limit intimal thickening in injured arteries by suppressing SMC activation through inhibition of SMC PDGF-B chain expression and PDGFRbeta activation.

Intima-media thickness of the carotid artery and the distribution of lipoprotein subclasses in men aged 40 to 49 years between whites in the United States and the Japanese in Japan for the ERA JUMP study

In men in the post-World War II birth cohort, that is, men aged 40 to 49 years, whites in the United States had significantly higher levels of intima-media thickness of the carotid arteries (IMT) than the Japanese in Japan (Electron-Beam Tomography and Risk Assessment Among Japanese and US Men in the Post World War II Birth Cohort [ERA JUMP] study). The difference remained after adjusting for traditional risk factors. Primary genetic effects are unlikely, given the degree to which IMT is increased in the Japanese who migrated to the United States. We investigated whether the differences in the distributions of lipoprotein subclasses explain the difference in IMT between the 2 populations. We examined population-based samples of 466 randomly selected men aged 40 to 49 years (215 whites from Allegheny County, Pennsylvania, and 241 Japanese from Kusatsu, Shiga, Japan). Lipoprotein subclasses were determined by nuclear magnetic resonance (NMR) spectroscopy. The whites had significantly higher levels of large very low-density lipoprotein particles and significantly lower levels of large high-density lipoprotein particles than the Japanese, whereas the 2 populations had similar levels of small low-density lipoprotein particles. The 2 populations had similar associations of IMT with NMR lipoproteins. Adjusting for NMR lipoproteins did not attenuate the significant difference in IMT between the 2 populations (0.671 +/- 0.006 mm for the whites and 0.618 +/- 0.006 mm for the Japanese, P = .01, mean +/- SE). Differences in the distributions of NMR lipoproteins between the 2 populations did not explain the higher IMT in the whites.

Expression of HIF-1alpha in injured arteries controls SDF-1alpha mediated neointima formation in apolipoprotein E deficient mice

OBJECTIVE

Hypoxia-inducible factor (HIF)-1alpha is the regulatory subunit of a transcriptional complex, which controls the recruitment of multipotent progenitor cells and tissue repair in ischemic tissue by inducing stromal cell-derived factor (SDF)-1alpha expression. Because HIF-1alpha can be activated under normoxic conditions in smooth muscle cells (SMCs) by platelet products, we investigated the role of HIF-1alpha in SDF-1alpha-mediated neointima formation after vascular injury.

METHODS AND RESULTS

Wire-induced injury of the left carotid artery was performed in apolipoprotein E-deficient mice. HIF-1alpha expression was increased in the media as early as 1 day after injury, predominantly in SMCs. Nuclear translocation of HIF-1alpha and colocalization with SDF-1alpha was detected in neointimal cells after 2 weeks. HIF-1alpha mRNA expression was induced at 6 hours after injury as determined by real-time RT-PCR. Inhibition of HIF-1alpha expression by local application of HIF-1alpha-siRNA reduced the neointimal area by 49% and significantly decreased the neointimal SMCs content compared with control-siRNA. HIF-1alpha and SDF-1alpha expression were clearly diminished in neointimal cells of HIF-1alpha-siRNA treated arteries.

CONCLUSIONS

HIF-1alpha expression is directly involved in neointimal formation after vascular injury and mediates the upregulation of SDF-1alpha, which may affect the stem cell-based repair of injured arteries.

Discrepancy between improvement of insulin sensitivity and that of arterial endothelial function in patients receiving antihypertensive medication

OBJECTIVES

We evaluated whether the changes in the insulin sensitivity observed in hypertensive patients following treatment with an angiotensin II receptor blocker (candesartan) or calcium-channel antagonist (amlodipine) might be related to improvement of the endothelial function (END) and/or plasma level of high-sensitive C-reactive protein (CRP) following such treatment.

METHODS AND RESULTS

Seventy-one hypertensive patients (age: 58 +/- 10 years) without obvious target organ damage were allocated randomly to treatment with either candesartan at the dose of 8 mg/day or amlodipine at the dose of 5 mg/day. At the start and end of the 8-month treatment period, the homeostasis model assessment index of insulin resistance (HOMA-IR index), plasma CRP and END, as assessed by changes in the forearm blood flow in reactive hyperemia, were determined. While significant improvement of END was observed in patients receiving either drug, only candesartan, but not amlodipine, also reduced the plasma CRP and HOMA-IR index (2.13 +/- 1.92 --> 1.53 +/- 1.47, P < 0.05). In the patients receiving treatment with candesartan, stepwise multivariate linear regression analysis revealed that the percent change in the HOMA-IR index was significantly and independently correlated with that in the plasma CRP (beta = 0.38, P < 0.05), but not with that in END:

CONCLUSION

Improvement of the END alone by the antihypertensive medication might not entirely explain the improvement of the insulin sensitivity observed in these patients. Additional mechanisms may be involved, and the anti-inflammatory effects of the medication observed in patients treated with candesartan may also be related, at least in part, to the observed improvement of insulin sensitivity.

Augmentation index and carotid intima-media thickness are differently related to age, C-reactive protein and oxidized low-density lipoprotein

OBJECTIVE

Ageing, plasma circulating C-reactive protein (CRP), oxidized low-density lipoprotein (OxLDL) and homocysteine (Hcy) are associated with atherosclerosis. The aim of this study was to evaluate the relationship between age, inflammatory and oxidative stress-related markers with functional and structural changes of the arteries in asymptomatic persons.

METHODS

CRP, OxLDL and Hcy were measured in 175 clinically healthy subjects, aged 40-70 years. Ultrasonography and pulse wave analysis were used to measure carotid intima-media thickness (IMT) and augmentation index (AIx).

RESULTS

OxLDL was correlated with IMT (r = 0.24, P = 0.003), whereas CRP was correlated with AIx (r = 0.21, P = 0.005). No correlation was detected between Hcy and AIx or age-adjusted IMT. There was a significant association between AIx and age <or=50 years (r = 0.33; P = 0.001) and between IMT and age > 50 years (r = 0.40; P = 0.001). In stepwise regression analysis age, weight, white blood cell count, OxLDL, heart rate and timing of the reflected waveform adjusted for height were significantly and independently associated with IMT (R = 0.41; P < 0.001). At the same time, AIx as the dependent variable correlated positively with age, gender, CRP and mean arterial pressure, and negatively with heart rate, weight and height, in stepwise regression analysis (R = 0.63; P < 0.001).

CONCLUSION

The results of the present study showed that CRP, OxLDL, Hcy and age are not similarly related to AIx and IMT in asymptomatic persons. The results suggest that CRP and younger age are related to arterial stiffness, whereas OxLDL and older age become more important determinants of structural changes of the arteries in asymptomatic persons.

Role of alpha1beta1-integrin in arterial stiffness and angiotensin-induced arterial wall hypertrophy in mice

We examined the arterial phenotype of mice lacking alpha(1)-integrin (alpha(1)(-/-)) at baseline and after 4 wk of ANG II or norepinephrine (NE) administration. Arterial mechanical properties were determined in the carotid artery (CA). Integrin expression, MAPK kinases, and focal adhesion kinase (FAK) were assessed in the aorta. No change in arterial pressure was observed in alpha(1)(-/-) mice. Elastic modulus-wall stress curves were similar in alpha(1)(-/-) and alpha(1)(+/+) animals, indicating no change in arterial stiffness. The rupture pressure was lower in alpha(1)(-/-) mice, demonstrating decreased mechanical strength. Lack of alpha(1)-integrin was accompanied by an increase in beta(1)-, alpha(v)-, and alpha(5)-integrins but no change in alpha(2)-integrin. ANG II increased medial cross-sectional area of the CA in alpha(1)(+/+), but not alpha(1)(-/-), mice, whereas equivalent pressor doses of NE did not produce a significant increase in either group. In alpha(1)(+/+) mice, ANG II induced alpha(1)-integrin expression and smooth muscle cell (SMC) hypertrophy in the CA in association with increased aortic expression of alpha-smooth muscle actin and smooth muscle myosin heavy chain and phosphorylation of ERK1/2, p38 MAPK, and FAK. ANG II did not induce SMC hypertrophy or phosphorylation of p38 MAPK and FAK in alpha(1)(-/-) mice. A functional anti-alpha(1)-integrin antibody inhibited in vitro the ANG II-induced phosphorylation of FAK and p38 MAPK. In conclusion, alpha(1)(-/-) mice exhibit a reduced mechanical strength at baseline and a lack of ANG II-induced SMC hypertrophy. These results emphasize the importance of alpha(1)beta(1)-integrin in p38 MAPK and FAK phosphorylation during vascular hypertrophy in response to ANG II.

Association of multiple inflammatory markers with carotid intimal medial thickness and stenosis (from the Framingham Heart Study)

Inflammatory markers, particularly C-reactive protein (CRP), predict incident cardiovascular disease and are associated with the presence of subclinical atherosclerosis. The relations between multiple inflammatory markers and direct measures of atherosclerosis are less well established. Participants in the Offspring Cohort of the Framingham Heart Study (n = 2,885, 53% women, mean age 59 years) received routine assessments of common carotid artery intima-media thickness (CCA-IMT), internal carotid artery intima-media thickness (ICA-IMT), and the presence or absence of > or =25% carotid stenosis by ultrasonography. Circulating inflammatory markers assessed from an examination 4 years later included CRP, interleukin-6 (IL-6), intercellular adhesion molecule-1, monocyte chemoattractant protein-1, P-selectin, and CD40 ligand. Assessed as a group, inflammatory markers were significantly associated with ICA-IMT (p = 0.01), marginally with carotid stenosis (p = 0.08), but not with CCA-IMT. Individually, with an increase from the 25th to 75th percentile in IL-6, there were significant increases in ICA-IMT and carotid stenosis (for ICA-IMT, estimated fold increase 1.04, 95% confidence interval 1.03 to 1.06, p = 0.0004; for carotid stenosis, odds ratio 1.25, 95% confidence interval 1.06 to 1.47, p = 0.007) after adjustment for age, gender, and established risk factors for atherosclerosis. There was a similar significant multivariate-adjusted association of CRP with ICA-IMT but not with carotid stenosis. Smoking appeared to modify the associations of ICA-IMT with CRP (p = 0.009) and with IL-6 (p = 0.006); the association was more pronounced in current (vs former or never) smokers. In conclusion, there were modest associations of inflammatory markers, particularly IL-6, with carotid atherosclerosis. This association appears more pronounced in current smokers than in former smokers and nonsmokers.

Expression of tumor necrosis factor receptor-1 in arterial wall cells promotes atherosclerosis

OBJECTIVE

Mechanisms by which tumor necrosis factor-alpha (TNF) contributes to atherosclerosis remain largely obscure. We therefore sought to determine the role of the arterial wall TNF receptor-1 (TNFR1) in atherogenesis.

METHODS AND RESULTS

Carotid artery-to-carotid artery interposition grafting was performed with tnfr1-/- and congenic (C57Bl/6) wild-type (WT) mice as graft donors, and congenic chow-fed apolipoprotein E-deficient mice as recipients. Advanced atherosclerotic graft lesions developed within 8 weeks, and had 2-fold greater area in WT than in tnfr1-/- grafts. While the prevalence of specific atheroma cells was equivalent in WT and tnfr1-/- grafts, the overall abundance of cells was substantially greater in WT grafts. WT grafts demonstrated greater MCP-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 expression at both early and late time points, and proliferating cell nuclear antigen expression at early time points. Aortic atherosclerosis was also reduced in 14-month-old apoe(-/-)/tnfr1(-/-) mice, as compared with cognate apoe-/- mice. In coculture with activated macrophages, smooth muscle cells expressing the TNFR1 demonstrated enhanced migration and reduced scavenger receptor activity.

CONCLUSIONS

TNFR1 signaling, just in arterial wall cells, contributes to the pathogenesis of atherosclerosis by enhancing arterial wall chemokine and adhesion molecule expression, as well as by augmenting medial smooth muscle cell proliferation and migration.