Carotid Injury Research Articles

DDAH1 Deficiency Attenuates Endothelial Cell Cycle Progression and Angiogenesis

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase (NOS). ADMA is eliminated largely by the action of dimethylarginine dimethylaminohydrolase1 (DDAH1). Decreased DDAH activity is found in several pathological conditions and is associated with increased risk of vascular disease. Overexpression of DDAH1 has been shown to augment endothelial proliferation and angiogenesis. To better understand the mechanism by which DDAH1 influences endothelial proliferation, this study examined the effect of DDAH1 deficiency on cell cycle progression and the expression of some cell cycle master regulatory proteins. DDAH1 KO decreased in vivo Matrigel angiogenesis and depressed endothelial repair in a mouse model of carotid artery wire injury. DDAH1 deficiency decreased VEGF expression in HUVEC and increased NF1 expression in both HUVEC and DDAH1 KO mice. The expression of active Ras could overcome the decreased VEGF expression caused by the DDAH1 depletion. The addition of VEGF and knockdown NF1 could both restore proliferation in cells with DDAH1 depletion. Flow cytometry analysis revealed that DDAH1 sRNAi knockdown in HUVEC caused G1 and G2/M arrest that was associated with decreased expression of CDC2, CDC25C, cyclin D1 and cyclin E. MEF cells from DDAH1 KO mice also demonstrated G2/M arrest that was associated with decreased cyclin D1 expression and Akt activity. Our findings indicate that DDAH1 exerts effects on cyclin D1 and cyclin E expression through multiple mechanisms, including VEGF, the NO/cGMP/PKG pathway, the Ras/PI3K/Akt pathway, and NF1 expression. Loss of DDAH1 effects on these pathways results in impaired endothelial cell proliferation and decreased angiogenesis. The findings provide background information that may be useful in the development of therapeutic strategies to manipulate DDAH1 expression in cardiovascular diseases or tumor angiogenesis.

Effects of Wenxiao Decoction (稳消方) on the expression of interleukin-6, intercellular adhesion molecular-1 and monocyte chemoattractant protein-1 in experimental atherosclerotic rabbits

To observe the effects of different doses of Wenxiao Decoction on the expression of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemoattractant protein-1 (MCP-1) in experimental atherosclerotic rabbits and to explore the mechanism by which it alleviates atherosclerosis. Sixty New Zealand rabbits were randomly divided into six groups: a blank group, a model group, a Simvastatin group, and high-, medium-, and low-dosage Wenxiao Decoction groups. Except for those in the blank group, all rabbits were fed with a high-cholesterol diet. Carotid atherosclerosis was established by balloon-induced carotid artery endothelium injury in conjunction with the high-cholesterol diet. After 8 weeks, all animals were euthanized to evaluate levels of IL-6 and ICAM-1 expressions (by enzyme linked immunosorbent assay) and of MCP-1 (by immunohistochemistry staining). The expressions of IL-6, ICAM-1, and MCP-1 were significantly increased in all groups except the blank group (P<0.05). However, the rabbits in the Wenxiao Decoction groups and the Simvastatin group showed significantly lower levels of IL-6, ICAM-1, and MCP-1 expression than those in the model group (P<0.05). The expressions of IL-6, ICAM-1, and MCP-1 in the highdosage Wenxiao Decoction group and the Simvastatin group were lower than those in the low-dosage Wenxiao Decoction group (P<0.05). The expression of MCP-1 in medium-dosage Wenxiao Decoction group was lower than that in the low-dosage group (P<0.05). High, medium, and low doses of Wenxiao Decoction can inhibit the expressions of IL-6, ICAM-1, and MCP-1, which may prevent and stabilize atherosclerotic plaques. There may be a direct relationship between dosage and therapeutic efficacy of Wenxiao Decoction.

Diet Induced Mild Hypercholesterolemia in Pigs: Local and Systemic Inflammation, Effects on Vascular Injury – Rescue by High-Dose Statin Treatment

ObjectiveThe aim of the present study was to comprehensively evaluate systemic and local inflammation as well as progression of vascular inflammation in normal and mechanically injured vessels in a large animal model of mild hypercholesterolemia. Our aim was also to test the effect of high-dose statin treatment on these processes.MethodsPigs were kept for 120 days on a standard diet (SD, n=7), high-cholesterol diet (HCD, n=7) or high-cholesterol diet with Atorvastatin starting after 50 days (STATIN, n=7). Left carotid artery balloon injury was conducted in all groups after 60 days of diet treatment. Biochemical analysis together with evaluation of blood and tissue markers of vascular injury and inflammation were performed in all groups at the end of experiment.ResultsHCD compared to SD induced systemic inflammation demonstrated by increased number of circulating monocytes and lymphocytes. HCD compared to SD induced also local inflammation demonstrated by adipocyte hypertrophy and infiltration of T-lymphocytes in abdominal white adipose tissue, activation of hepatic stellate cells with infiltration of T- and B-lymphocytes and macrophages in the liver and increased macrophage content in lung parenchyma. These changes were accompanied by increased Intima/Media thickness, stenosis, matrix deposition and activated T-cell infiltrates in injured but not in uninjured contralateral carotid artery as we previously reported. The treatment with high-dose statin attenuated all aspects of systemic and local inflammation as well as pathological changes in injured carotid artery.ConclusionsDiet related mild hypercholesterolemia induce systemic and local inflammation in the liver, lung and adipose tissue that coincide with enhanced inflammation of injured vessel but is without deleterious effect on uninjured vessels. High dose statin attenuated systemic and local inflammation and protected injured vessels. However, finding exact role of reduced systemic and remote inflammation in vascular protection requires further studies.

Nitric oxide is less effective at inhibiting neointimal hyperplasia in spontaneously hypertensive rats

Exogenous administration of nitric oxide (NO) markedly decreases neointimal hyperplasia following arterial injury in several animal models. However, the effect of NO on neointimal hyperplasia in hypertension remains unknown. Here, we employ the spontaneously hypertensive rat (SHR) strain, inbred from Wistar Kyoto (WKY) rats, and the carotid artery balloon injury model to assess the effects of NO on neointimal hyperplasia development. 2weeks after arterial injury, we showed that both rat strains developed similar levels of neointimal hyperplasia, but local administration of NO was less effective at inhibiting neointimal hyperplasia in the SHR compared to WKY rats (58% vs. 79%, P<0.001). Interestingly, local administration of NO did not affect systemic blood pressure in either rat strain. Compared to WKY, the SHR displayed more proliferation in the media and adventitia following balloon injury, as measured by BrdU incorporation. The SHR also showed more inflammation in the adventitia after injury, as well as more vasa vasorum, than WKY rats. NO treatment reduced the vasa vasorum in the SHR but not WKY rats. Finally, while NO decreased both injury-induced proliferation and inflammation in the SHR, it did not return these parameters to levels seen in WKY rats. We conclude that NO is less effective at inhibiting neointimal hyperplasia in the SHR than WKY rats. This may be due to increased scavenging of NO in the SHR, leading to diminished bioavailability of NO. These data will help to develop novel NO-based therapies that will be equally effective in both normotensive and hypertensive patient populations.

Unilateral neck pain: a case of Eagle syndrome with associated nontraumatic styloid fracture

We present a case of Eagle syndrome in a 77-year-old woman with associated aneurysm and nontraumatic styloid process fracture, without history of tonsillectomy, who presented to the emergency department. The first set of symptoms associated with the elongation of the temporal styloid process and/or the calcification of the stylomandibular or stylohyoid ligaments was described by Eagle in 1937. Classically, unilateral pain in the oropharynx radiating to the neck and face that is exacerbated by head turning and neck rotation is characteristic of Eagle syndrome. However, styloid process elongation and stylohyoid calcification found in Eagle syndrome may also present with vascular symptomsthrough impingement and injury of the carotid arteries. Eagle syndrome is a rare but important differential that the emergency physician must consider in a patient with unilateral neck pain and positional neurological symptoms with head turning and in posttonsillectomy patients. Patients with medical history of Eagle syndrome presenting with neck pain and especially neurological symptomsmust be thoroughly evaluated for carotid and jugular venous injury. Specifically, the decision to obtain computed tomography and computed tomographic angiography to evaluate for carotid artery injury is important for patient management and disposition.

Bone marrow derived cells with defective c-Myb activity protect against neointimal remodeling following injury

Purpose: We previously showed that the transcription factor c-myb regulates the differentiation of contractile vascular smooth muscle cells in embryonic stem cell-derived embryoid bodies. While we also showed that c-Myb regulates the expansion of a specific embryonic hemangiogenic progenitor, it is unclear if this population has a role in the adult animal. However, the role of c-Myb in the proliferation and potential (trans)differentiation of bone marrow (BM)-derived vs. vessel-resident cells in arterial remodelling in the adult has eluded genetic examination due to the embryonic lethality of c-myb-/- mice from hematopoietic failure. To examine the role of c-myb in BM-derived vs. vessel-resident cells, we have used a mouse harboring a non-lethal point mutation resulting in a hypomorphic (h) allele of c-myb with defective c-Myb activity. Methods and results: Histology of common carotid arteries of 12 wk-old male c-mybh/h and c-mybwt mice was performed 14 days after carotid artery wire denudation injury. Uninjured vessels from wt and h/h mice did not differ in lumen, intima, and media morphometry or I/M ratio. Following wire injury, h/h mice showed reduced intima formation (16,723±2,550 vs. 31,402±49,890 μm2; p<0.05; N=6-7/group) and I/M ratio (0.313±0.044 vs. 0.565±0.089; p<0.01) than wt controls. To determine the relative contribution of BM-derived vs. vessel cells in arterial remodeling, reciprocal BM transplants were performed in 5wk old wt and h/h mice, which were allowed to reconstitute their BM for 7 wks before wire injury. Compared to wt→wt mice, injured arteries from h/h→wt mice had decreased intima formation (19,222±2,622 vs. 8,080±1,337 μm2; p<0.0001; N= 7/group) and I/M ratio (0.491±0.068 vs. 0.217±0.01; p<0.0001). However, injured arteries from wt→h/h mice had no differences in intima formation as compared to h/h→h/h mice (14,519±486 vs. 13,437±1,175 μm2; p=NS; N= 7/group), with no differences observed in uninjured BM-transplanted control arteries. Conclusions: The blunted arterial remodelling response observed in h/h→wt mice is due to a c-Myb dependent defect in BM-derived cell populations that participate in the pathogenesis of neointimal proliferation following arterial injury.

Inhibition of reactive oxygen species generation attenuates TLR4-mediated proinflammatory and proliferative phenotype of vascular smooth muscle cells

Reactive oxygen species (ROS) are associated with inflammation and vasculature dysfunction. This study aimed to investigate the potential role of the ROS on vascular Toll-like receptor 4 (TLR4)-mediated proinflammatory and proliferative phenotype of vascular smooth muscle cells (VSMCs). A wire-induced carotid injury model was used in male TLR4-deficient (TLR4−/−) and wild-type C57BL/6J mice to induce neointima formation. In the presence or absence of the ROS scavenger apocynin for 14 days, increased TLR4 and proinflammatory cytokines were observed in wire injury-induced carotid neointima and in platelet-derived growth factor-BB (PDGF-BB)-stimulated VSMCs. The TLR4−/− protected the injured carotid from neointimal formation and impaired the cellular proliferation and migration in response to PDGF-BB. Apocynin attenuated intimal hyperplasia. Pre-treatment with apocynin significantly inhibited intracellular ROS generation, accompanied by a significant suppression of TLR4 and proinflammatory cytokines expression, and VSMC proliferation and migration. However, the results were not obvious in TLR4−/− condition. These findings highlight the importance of ROS inhibition in TLR4-mediated proinflammatory and proliferative phenotype of VSMCs, and suggest ROS as an essential therapeutic target for TLR4-associated vascular inflammation and vascular diseases.

Hyperbaric Oxygen Decreases Intimal Thickness and Area After Carotid Artery Balloon Injury in a Rat Model

Clinical studies have suggested a benefit for hyperbaric oxygen (HBO) treatment in decreasing symptomatic restenosis after coronary angioplasty. We hypothesize that HBO treatment will decrease hyperplastic intimal area after arterial balloon injury in a rat. Fifty-four male Sprague-Dawley rats (Charles River Laboratories, Wilmington, MA) were randomly assigned either to room air (n = 27) or a treatment group (n = 27) receiving HBO treatment (2 hyperbaric treatments of 100% oxygen at 2 bars for 90 min). A 2F balloon-tipped catheter was used to injure the right common carotid arteries, which were harvested at 7, 14, and 28 days. Postinjury intimal thickness and area were measured from hematoxylin-eosin-stained specimens at each time point. Computer-assisted histomorphometry was used to calculate maximal intimal thickness, relative intimal thickness (ratio of intimal to intimal plus medial thickness), intimal area, and the intimal to medial area ratio. There was a 42.3% reduction in maximal intimal thickness (P = 0.0012) and a 36.5% reduction in intimal area (P = 0.0337) at day 28 in the HBO-treated group (mean ± standard error [SE], 0.0425 ± 0.0054 mm for maximal thickness and 0.065 ± 0.0056 mm(2) for area) when compared to the normoxic group (0.0737 ± 0.004 mm for maximal thickness and 0.0413 ± 0.0074 mm(2) for area). The relative intimal thickness also showed a 28.3% reduction at day 28 in the HBO-treated group (ratio of 0.38 ± 0.0329) compared to the normoxic group (ratio of 0.53 ± 0.0141; P = 0.0065). Our results indicate that HBO treatment decreases maximal intimal thickness and intimal area of the carotid artery after balloon injury. This could have significant clinical implications on the increasing number of endovascular interventions in vascular surgery and cardiology.

Sirolimus-loaded stealth colloidal systems attenuate neointimal hyperplasia after balloon injury: A comparison of phospholipid micelles and liposomes

Restenosis after angioplasty remains a serious complication in clinical cardiology. This study aims to investigate the stealth colloidal systems for local intra-arterial drug delivery. Micelles from polyethylene glycol conjugated with phosphatidylethanolamine and PEGylated liposomes loaded with sirolimus were prepared and characterized with regard to their loading efficiency, particle size distribution, zeta potential, morphology, nuclear magnetic resonance spectroscopy, drug release profile and stability. The antirestenotic effects of the sirolimus-loaded micelles (14 nm) and liposomes (90 nm) were evaluated and compared in the rat carotid injury model following local intravascular delivery. In comparison to control groups, treatment of balloon injured rats with drug loaded micelles and nanoliposomes significantly reduced vascular stenosis by 42% and 19%, respectively (P<0.05). In addition, the luminal area was significantly enlarged by 39% and 60% following treatment with sirolimus-loaded liposomes and micelles, respectively (P<0.05). Immunohistochemistry revealed that sirolimus-loaded nanocarriers suppressed cell proliferation (Ki67-positive cells) as compared to control groups without affecting the density of smooth muscle actin staining. These results suggest that both colloidal nanocarriers could serve as effective intramural drug delivery systems for the treatment of restenosis; however, phospholipid based micelles provided better antirestenotic effects than PEGylated liposomes.

Rapid Estrogen Receptor Signaling Mediates Estrogen-Induced Inhibition of Vascular Smooth Muscle Cell Proliferation

The proliferation of vascular smooth muscle cells (VSMCs) plays a crucial role in vascular diseases, such as atherosclerosis and restenosis, after percutaneous coronary intervention. Many studies have shown that estrogen inhibits VSMC proliferation in response to vascular injury in the mouse carotid injury model. However, the mechanisms that mediate these effects remain unclear. Here, we investigated the mechanisms by which estrogen inhibits VSMC proliferation. We established a novel transgenic mouse line, referred to as the disrupting peptide mice, in which rapid estrogen receptor (ER)-mediated signaling is abolished by overexpression of a peptide that prevents the ER from forming a signaling complex necessary for rapid signaling. Carotid artery VSMCs from disrupting peptide mice or littermate wild-type female mice were obtained by the explant method. In VSMCs derived from wild-type mice, estrogen significantly inhibited VSMC proliferation. Phosphorylation levels of Akt and extracellular regulated kinase induced by platelet derived growth factor were significantly inhibited by estrogen pretreatment. Estrogen enhanced complex formation between ERα and protein phosphatase 2A (PP2), and enhanced PP2A activity. The blockade of PP2A activity abolished the estrogen-induced antiproliferative effect on VSMCs. In contrast, none of these effects of estrogen observed in the wild-type VSMCs were observed in VSMCs derived from disrupting peptide mice. These results support that rapid, non-nuclear ER signaling is required for estrogen-induced inhibition of VSMC proliferation, and further that PP2A activation by estrogen mediates estrogen-induced antiproliferative effects. These findings support that PP2A activation via rapid, non-nuclear ER signaling may be a novel target for therapeutic approaches to inhibit VSMC proliferation, which plays a central role in atherosclerosis and restenosis.

DNA Enzyme ED5 Depletes Egr-1 and Inhibits Neointimal Hyperplasia in Rats

Objectives: Depletion of early growth response factor-1 (Egr-1) by a DNA enzyme, ED5, inhibits neointimal hyperplasia (NH) following vascular injury by an unknown mechanism. The aim of this study was to characterize the effects of ED5 in a rat carotid injury model in order to elucidate the mechanism by which ED5 inhibits NH. Methods: ED5 was transfected into the arterial wall of Wistar rats using FuGENE6 transfection reagent following artery balloon injury. Hematoxylin and eosin staining, immunohistochemistry, real-time reverse transcription polymerase chain reaction and Western blotting analysis were used to characterize the response to ED5. Results: NH decreased significantly in the ED5- plus FuGENE6-treated rats (p < 0.05) compared with the control groups, and this was accompanied by a reduced inflammatory response. Egr-1 mRNA and protein levels were significantly decreased in the ED5-treated group, as expected. The decrease in Egr-1 was accompanied by decreases in the mRNA and protein levels of PDGF-BB, Cyclin D1, CDK4, MCP-1, and ICAM-1 (p < 0.05). Conclusions: Transfection of the Egr-1-specific synthetic DNA enzyme ED5 significantly reduced NH after injury in rats, at least in part, as a result of decreased expression of downstream proliferative genes such as PDGF-BB, Cyclin D1, CDK4, and the inflammatory factors MCP-1 and ICAM-1.

Percutaneous Thrombin Injection with a Distal Embolic Protection Device for Treatment of a Common Carotid Artery Pseudoaneurysm

Carotid artery pseudoaneurysm is a rare complication from placement of an internal jugular triple lumen catheter. Endovascular stenting is the favored treatment option in the setting of traumatic carotid injury. In other parts of the body, specifically the femoral artery, thrombin injection has become the standard of care. We intend to show that effective management of carotid pseudoaneurysms can also be achieved with thrombin injection after placement of a distal embolic protection device.

Smooth Muscle–Selective Inhibition of Nuclear Factor‐κB Attenuates Smooth Muscle Phenotypic Switching and Neointima Formation Following Vascular Injury

BackgroundVascular proliferative diseases such as atherosclerosis are inflammatory disorders involving multiple cell types including macrophages, lymphocytes, endothelial cells, and smooth muscle cells (SMCs). Although activation of the nuclear factor‐κB (NF‐κB) pathway in vessels has been shown to be critical for the progression of vascular diseases, the cell‐autonomous role of NF‐κB within SMCs has not been fully understood.Methods and ResultsWe generated SMC‐selective truncated IκB expressing (SM22α‐Cre/IκBΔN) mice, in which NF‐κB was inhibited selectively in SMCs, and analyzed their phenotype following carotid injury. Results showed that neointima formation was markedly reduced in SM22α‐Cre/IκBΔN mice after injury. Although vascular injury induced downregulation of expression of SMC differentiation markers and myocardin, a potent activator of SMC differentiation markers, repression of these markers and myocardin was attenuated in SM22α‐Cre/IκBΔN mice. Consistent with these findings, NF‐κB activation by interleukin‐1β (IL‐1β) decreased expression of SMC differentiation markers as well as myocardin in cultured SMCs. Inhibition of NF‐κB signaling by BAY 11‐7082 attenuated repressive effects of IL‐1β. Of interest, Krüppel‐like factor 4 (Klf4), a transcription factor critical for regulating SMC differentiation and proliferation, was also involved in IL‐1β‐mediated myocardin repression. Promoter analyses and chromatin immunoprecipitation assays revealed that NF‐κB repressed myocardin by binding to the myocardin promoter region in concert with Klf4.ConclusionsThese results provide novel evidence that activation of the NF‐κB pathway cell‐autonomously mediates SMC phenotypic switching and contributes to neointima formation following vascular injury.

Local inhibition of ornithine decarboxylase reduces vascular stenosis in a murine model of carotid injury

Polyamines are organic polycations playing an essential role in cell proliferation and differentiation, as well as in cell contractility, migration and apoptosis. These processes are known to contribute to restenosis, a pathophysiological process often occurring in patients submitted to revascularization procedures. We aimed to test the effect of α-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, on vascular cell pathophysiology in vitro and in a rat model of carotid arteriotomy-induced (re)stenosis. The effect of DFMO on primary rat smooth muscle cells (SMCs) and mouse microvascular bEnd.3 endothelial cells (ECs) was evaluated through the analysis of DNA synthesis, polyamine concentration, cell viability, cell cycle phase distribution and by RT-PCR targeting cyclins and genes belonging to the polyamine pathway. The effect of DFMO was then evaluated in arteriotomy-injured rat carotids through the analysis of cell proliferation and apoptosis, RT-PCR and immunohistochemical analysis of differential gene expression. DFMO showed a differential effect on SMCs and on ECs, with a marked, sustained anti-proliferative effect of DFMO at 3 and 8 days of treatment on SMCs and a less pronounced, late effect on bEnd.3 ECs at 8 days of DFMO treatment. DFMO applied perivascularly in pluronic gel at arteriotomy site reduced subsequent cell proliferation and preserved smooth muscle differentiation without affecting the endothelial coverage. Lumen area in DFMO-treated carotids was 49% greater than in control arteries 4 weeks after injury. Our data support the key role of polyamines in restenosis and suggest a novel therapeutic approach for this pathophysiological process.

Increasing our IQ of vascular smooth muscle cell migration with IQGAP1. Focus on “IQGAP1 links PDGF receptor-β signal to focal adhesions involved in vascular smooth muscle cell migration: role in neointimal formation after vascular injury”

<i>Increasing our IQ of vascular smooth muscle cell migration with IQGAP1</i>. Focus on “IQGAP1 links PDGF receptor-β signal to focal adhesions involved in vascular smooth muscle cell migration: role in neointimal formation after vascular injury”

Differential Endothelial Coverage, Response to Injury and Neointimal Integration of CX3CR1/Smooth Muscle-Like Cells after Carotid or Femoral Arterial Injury

Background: Previously, we established the importance of the CX3CL1/CX3CR1 axis in the promotion of myeloid cell differentiation into neointimal smooth muscle-like cells (SMLC). Methods: In this study, acute (24 h) endothelial coverage and CX3CL1 expression as well as chronic (2 weeks) vascular remodeling was examined with respect to whether myeloid CX3CR1⁺ SMLC number in the neointima differed between carotid and femoral artery wire injury. Results and Conclusion: Twenty-four hours after injury, CX3CL1 expression was significantly elevated in injured carotid compared to femoral arteries. In mice with CX3CR1 promoter-driven expression of green fluorescent protein, neointima formation was significantly greater (p < 0.05) 2 weeks after injury in femoral versus carotid arteries as determined by the intima/media ratio. Although the percentage of F4/80/CX3CR1⁺ cell integration was similar in both models, the carotid lesion had greater proportions of cells coexpressing CX3CR1 and both α-smooth muscle actin and calponin (p < 0.05). Wire injury of carotid arteries was associated with greater CX3CL1 expression in the acute phase followed by greater CX3CR1 coexpressing SMLC content in later lesions as well as less neointima formation than in femoral arteries. This may, in part, explain the variability in lesion composition after carotid versus femoral wire injury.

Abstract 302: Smooth Muscle Cell Mineralocorticoid Receptors Directly Mediate Aldosterone-induced Remodeling After Vascular Injury Via Type 1 Vegf Receptors

Background and Significance Endothelial damage initiates vascular remodeling with smooth muscle cell (SMC) proliferation and vascular fibrosis. Excessive remodeling, as in restenosis after vascular procedures or atherosclerosis, limits blood flow to distal tissues. In animals, aldosterone (aldo) infusion enhances remodeling which is reversed by aldo antagonists, implicating the mineralocorticoid receptor (MR). We previously showed that MR is expressed in SMC and that aldo induces the type 1 VEGF receptor (VEGFR1) in injured vessels. Hypothesis and Results We hypothesize that aldo promotes pathological vascular remodeling by directly activating MR in SMC and promoting SMC proliferation via VEGFR1 signaling. We show in vivo that aldo does not affect re-endothelialization after injury supporting our focus on SMC. To test this hypothesis we measured aldo-induced remodeling after wire carotid injury in mice with inducible SMC-specific deletion of MR (SMC-MR-KO). The 80% increase in SMC proliferation with aldo in control littermates is completely prevented in SMC-MR-KO mice (p&lt;0.005, n=11). To examine the mechanism, mouse carotid SMC were treated with aldo in vitro producing a dose dependent proliferative response (1,5,10 and100nM aldo, 9%±2, 17%±3, 21%±6, and 25%±7 vs control, respectively, p&lt;0.05, n=8). The increase in proliferation with 10 nM aldo+IgG was completely inhibited by treatment with specific VEGFR1-blocking antibody (Ab, p=0.04, n=8). Immunohistochemistry of carotid vessels reveals that VEGFR1 is induced in SMC after injury and further enhanced by aldo (55%±0.5 increase with injury, 74%± 0.5 with aldo+injury vs uninjured control, p&lt;0.05, n=8).We examined the role of VEGFR1 in vivo and VEGFR1 blockade significantly reduces aldo-induced SMC proliferation after injury (46%±4 decrease vs aldo+IgG, p&lt;0.05, n=9). Tail cuff measurements reveal no difference in blood pressure with any of the treatments. Conclusions These data support that SMC MR directly mediates aldo-induced vascular remodeling independent blood pressure. The mechanism involves VEGFR1 that is induced on SMC in the area of injury. This study supports exploring VEGFR1-blocking drugs to prevent pathological vascular remodeling induced by aldo in humans.

Diabetes confers a vasoprotective role to the neurocompensatory response elicited by carotid balloon injury: Consequences on contralateral carotid tone and blood flow

The purpose from this study was to investigate the consequences of sensory neurocompensation to carotid balloon injury in diabetic rats on angiotensin II-induced contraction and basal blood flow in contralateral carotid. Concentration-response curves for angiotensin II and blood flow were obtained in contralateral carotid from non-treated or capsaicin-treated streptozotocin-induced diabetic rats that underwent carotid balloon injury. Diabetes increased angiotensin II-induced contraction and impaired the blood flow in non-operated rat carotid. In diabetic rats, balloon injury led to neointima formation, which reduced the blood flow in ipsilateral carotid. Carotid balloon injury in diabetic rats reduced angiotensin II-induced contraction and restored the blood flow in contralateral carotid when compared to diabetic non-operated rat carotid. Capsaicin inhibited the effects evoked by carotid balloon injury on diabetic rat contralateral carotid. Endothelium removal, PEG-catalase (hydrogen peroxide scavenger) or l-NPA (neuronal nitric oxide synthase, nNOS, inhibitor) increased angiotensin II-induced contraction in contralateral carotid from diabetic operated rats to the levels observed in diabetic non-operated rat carotid. Our findings suggest that carotid balloon injury in diabetic rats elicits a neurocompensation that attenuates the diabetic hyperreactivity to angiotensin II in contralateral carotid by a sensory nerves-dependent mechanism mediated by hydrogen peroxide derived from endothelial nNOS. This sensory mechanism also restored the blood flow in this vessel, compensating the impaired blood flow in diabetic rat ipsilateral carotid. Thus, our major conclusions are that Diabetes confers a vasoprotective significance to the neurocompensation to carotid balloon injury in preventing further damage at carotid cerebral irrigation after angioplasty in diabetic subjects.

Demethoxycurcumin, a major active curcuminoid from Curcuma longa, suppresses balloon injury induced vascular smooth muscle cell migration and neointima formation: An in vitro and in vivo study

Curcumin has been shown to affect platelet-derived growth factor (PDGF)- and tumor necrosis factor (TNF)-α-elicited vascular smooth muscle cell (VSMC) migration and inhibit neointima formation following vascular injury. However, whether two other curcuminoids isolated from Curcuma longa, demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), also demonstrate antimigratory activity in VSMCs similar to that of curcumin remain uncharacterized. Based on 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide and proliferating cell nuclear antigen immunostaining analyses as well as changes in intima/media ratios, we show that DMC exhibits more potent effects than the other curcuminoids. We aimed to evaluate the effects and characterize the molecular mechanisms of DMC on VSMC migration and neointima formation in a carotid injury model. DMC decreased the expression of matrix metalloproteinase 2/9 and inhibited VSMC migration as demonstrated by in vitro scratch wound and transwell assays. Furthermore, DMC may inhibit the migration of VSMCs by reducing the expression of matrix metalloproteinase 2/9 via downregulation of the focal adhesion kinase/phosphatidylinositol 3-kinase (PI3K)/AKT (protein kinase B) and phosphoglycerate kinase 1/extracellular signal regulated kinase 1/2 signaling pathways. Using a rat carotid arterial injury model, we show that DMC treatment was more potent than treatment with the other curcuminoids with respect to reducing intima/media ratios and the number of proliferating cells. DMC should be considered for therapeutic use in preventing VSMC migration and attenuating restenosis following balloon-mediated vascular injury.

Part Two: Against the Motion. Completion Angiography is Unnecessary Following Carotid Endarterectomy

Part Two: Against the Motion. Completion Angiography is Unnecessary Following Carotid Endarterectomy