Hyperplasia In Rat Carotid Artery Research Articles

Methyl donor diet attenuates intimal hyperplasia after vascular injury in rats

Environmental factors, particularly dietary habits, play an important role in cardiovascular disease susceptibility and progression through epigenetic modification. Previous studies have shown that hyperplastic vascular intima after endarterectomy is characterized by genome-wide hypomethylation. The purpose of this study was to investigate whether methyl donor diet affects intimal hyperplasia and the possible mechanisms involved. Intimal hyperplasia was induced in SD rats by carotid artery balloon injury. From 8 d before surgery to 28 d after surgery, the animals were fed a normal diet (ND) or a methyl donor diet (MD) supplemented with folic acid, vitamin B12, choline, betaine, and zinc. Carotid artery intimal hyperplasia was observed by histology, the effect of MD on carotid protein expression was analyzed by proteomics, functional clustering, signaling pathway, and upstream-downstream relationship of differentially expressed proteins were analyzed by bioinformatics. Results showed that MD attenuated balloon injury-induced intimal hyperplasia in rat carotid arteries. Proteomic analysis showed that there were many differentially expressed proteins in the common carotid arteries of rats fed with two different diets. The differentially expressed proteins are mainly related to the composition and function of the extracellular matrix (EMC), and changes in the EMC can lead to vascular remodeling by affecting fibrosis and stiffness of the blood vessel wall. Changes in the levels of vasculotropic proteins such as S100A9, ILF3, Serpinh1, Fbln5, LOX, HSPG2, and Fmod may be the reason why MD attenuates intimal hyperplasia. Supplementation with methyl donor nutrients may be a beneficial measure to prevent pathological vascular remodeling after injury.

Suppression of circDcbld1 Alleviates Intimal Hyperplasia in Rat Carotid Artery by Targeting miR-145-3p/Neuropilin-1

We replicated the rat common carotid artery (CCA) intima hyperplasia model and found the expression of a circular RNA, circRNA_009723 (circDcbld1), was markedly increased in the CCA with intimal hyperplasia. In vitro, the suppression of circDcbld1 in rat vascular smooth muscle cells (VSMCs) led the increase of contractile smooth muscle cell markers and the decrease of cell migration. In vivo, the injection of chemically modified circDcbld1 small interfering RNA (siRNA) lessened the formation of neointima in rat CCA after balloon injury. Further experiments proved that circDcbld1, as a competing endogenous RNA, interacted with miR-145-3p and upregulated the level of neuropilin-1 (Nrp1), thereby regulating the migration of VSMCs. In this study, we demonstrated a new mechanism by which circular RNA promotes intimal hyperplasia. We deem that intervention in the circDcbld1-miR-145-3p/Nrp1 pathway might be a feasible approach to alleviate the post-injury intimal hyperplasia.

Sildenafil Reduces Neointimal Hyperplasia after Angioplasty and Inhibits Platelet Aggregation via Activation of cGMP-dependent Protein Kinase

Sildenafil is known to reduce cardiac hypertrophy through cGMP-dependent protein kinase (cGK) activation. Studies have demonstrated that cGK has a central switching role in modulating vascular smooth muscle cell (VSMC) phenotype in response to vascular injury. Here, we aimed to examine the effects of cGK activation by sildenafil on neointimal formation and platelet aggregation. After vascular injury, neointimal hyperplasia in rat carotid arteries was significantly reduced in the sildenafil-treated group. This effect of sildenafil was accompanied by the reduction of viability and migration of VSMCs. Further experiments showed that the increased cGK activity by sildenafil inhibited platelet-derived growth factor-induced phenotype change of VSMCs from a contractile form to a synthetic one. Conversely, the use of cGK inhibitor or gene transfer of dominant-negative cGK reversed the effects of sildenafil, increasing viability of VSMCs and neointimal formation. Interestingly, sildenafil significantly inhibited platelet aggregation induced by ADP or thrombin. This effect was reversed by cGK inhibitor, suggesting that sildenafil inhibits platelet aggregation via cGK pathway. This study demonstrated that sildenafil inhibited neointimal formation and platelet aggregation via cGK pathway. These results suggest that sildenafil could be a promising candidate for drug-eluting stents for the prevention of both restenosis and stent thrombosis.

Abstract 62: Sildenafil Inhibits Neointimal Hyperplasia After Angioplasty, and Reduces Platelet Aggregation

Background: Restenosis and stent thrombosis after stent implantation are one of the devating issues in interventional cardiology. Sildenafil has shown its effect in reducing cardiac hypertrophy as well as improving erectile dysfunction through protein kinase G (PKG) activation. Some studies have demonstrated that PKG occupies a central switching role in modulating vascular smooth muscle cell (VSMC) phenotype in response to vascular injury. In this study, we investigated the effects of PKG activation by sidenafil on platelet aggregation and neointimal hyperplasia. Methods and Results: In terms of restenosis after vascular injury, sildenafil significantly reduced neointimal hyperplasia in rat carotid arteries compared to control group. This effect of sildenafil was accompanied by the reduction of viability, cell cycle progression, and migration of VSMCs. This was also confirmed in the injured arteries in vivo. Further studies showed that the increased PKG activity by sildenafil inhibited PDGF-stimulated phenotype change of VSMCs from a contractile to a synthetic form. Conversely, the use of PKG inhibitor or gene transfer of dominant-negative PKG reversed the effects of sildenafil, resulting in the increased viability of VSMCs and neointimal formation. In addition, the mice treated with sidenafil showed the facilitated re-endothelialization, compared to control group. Furthermore, we confirmed the effect of sidenafil through PKG activation using cGK-KO mice. Interestingly, sildenafil significantly inhibited platelet aggregation induced by ADP or thrombin. This effect was reversed by PKG inhibitor, suggesting that sildenafil inhibits platelet aggregation via PKG pathway. Furthermore, assays for VASP phosphorylation and P-selectin activation showed the same inhibitory effect of sildenafil on platelet activation. Conclusions: This study showed that sildenafil inhibits not only platelet aggregation, but also neointimal hyperplasia through the PKG pathway. These findings suggest that sildenafil could be a promising candidate drug of drug-eluting stents for the prevention of restenosis without other complications such as stent thrombosis.

Abstract 332: Inhibition of the Enhancer of Zeste Homolog Family Mitigates Intimal Hyperplasia in Rat Carotid Arteries

Rationale: The enhancer of zeste homologs 1 and 2 (EZH1 and EZH2) are histone-lysine N-methyltransferases that modify histones by methylation which leads to transcriptional repression. It has recently been shown that EZH1 and EZH2 play an important role in various cancers. Whether they play a role in recurrent vascular diseases is not known. Objective: We assessed whether EZH1 and EZH2 are important contributors to the development of intimal hyperplasia (IH) and restenosis. Methods and Results: Following rat carotid balloon angioplasty, EZH2 showed highest expression at day 3 post procedure and then decreased at day 7 in injured arteries, as determined by Western blotting. Change of EZH1 is less prominent. Dual inhibition of EZH1 and EZH2 through peri-adventitial administration of a selective inhibitor, UNC-1999, effectively inhibited intimal hyperplasia, with ~40% reduction in the ratio of intima to media (I/M). Moreover, in cultured primary rat smooth muscle cells (SMCs) as well as MOVAS cells, pretreatment with 5μM UNC-1999 resulted in a 60% decrease in cell proliferation and ~80% reduction of migration that were stimulated by PDGF-BB. Simultaneous knockdown of EZH1 and EZH2, as well as knockdown of their shared scaffold protein(EED), led to effective inhibition of proliferation and migration of SMCs. However, knockdown of EZH2 alone did not recapitulate the effects of dual inhibition of EZH1 and EZH2. Conclusions: This study demonstrates that dual inhibition of EZH1 and EZH2, both histone modifiers, mitigates intimal hyperplasia in vivo and attenuates PDGF-BB stimulated SMC proliferation and migration in vitro.

Blocking bromo- and extra-terminal bromodomains mitigates intimal hyperplasia in rat carotid arteries: role of epigenetic reader in vascular disease

Zhang, Mengxue MD; Wang, Bowen; Takayama, Toshio MD, PhD; Shi, Xudong MD, PhD; Roenneburg, Drew Al.; Kent, Craig K. MD, FACS; Guo, Lian-Wang PhD Author Information

Clinical characteristics and outcomes of unilateral and bilateral lower limb deep vein thrombosis: ultrasonography-based study of 6420 cases

Blocking bromoand extra-terminal bromodomains mitigates intimal hyperplasia in rat carotid arteries: role of epigenetic reader in vascular disease Mengxue Zhang, MD, Bowen Wang, Toshio Takayama, MD, PhD, Xudong Shi, MD, PhD, Drew Al Roenneburg, K Craig Kent, MD, FACS, Lian-Wang Guo, PhD Wisconsin Institute for Medical Research, Madison, WI; University of Wisconsin School of Medicine and Public Health, Madison, WI

Electroporation-mediated angiotensin II type 2 receptor gene transfected into rat carotid arteries and the effects of AT2R gene transfer on neointimal hyperplasia in rat carotid arteries after balloon angioplasty.

AimTo study the effects of Electroporation on the angiotensin type 2 receptor (AT2R) transfected into rat carotid arteries and study the effects of AT2R gene transfer on neointimal hyperplasia in...

Human tissue kallikrein 1 gene delivery inhibits PDGF-BB-induced vascular smooth muscle cells proliferation and upregulates the expressions of p27Kip1 and p2lCip1

Tissue kallikrein 1 cleaves kininogen substrate to produce vasoactive kinin peptides that have been implicated in inhibiting neointimal hyperplasia in rat carotid arteries after balloon injury. However, its effects on the proliferation, cell cycle and its mechanisms, for example, cyclin-dependent kinase inhibitors, p27(Kip1) and p2l(Cip1) in vascular biology are poorly understood. The objective of this study was to explore the effects of human tissue kallikrein 1 (hTK1) mediated by recombinant adenovirus (Ad-hTK1) on proliferation and cell cycle of vascular smooth muscle cells (VSMCs) derived from spontaneously hypertensive rats induced by platelet-derived growth factor-BB (PDGF-BB) in vitro. The results showed that, within a given multiplicity of infection (MOI) and time, the hTK1 gene delivery inhibited PDGF-BB-stimulating VSMCs growth in a concentration-dependent (20-100 MOI) and time-dependent (2-5 days) manner by cell counting, with a peak inhibition rate at 36.3% at 72 h (P < 0.01). In addition, hTK1 gene delivery significantly suppressed PDGF-BB-induced proliferation of VSMCs by methyl thiazolyl tetrazoliuin assay, and decreased the percentage of cells in the S phase and in DNA synthesis by flow cytometry, with a peak inhibition rate at 30.2 and 36.4%, respectively (P < 0.01). Western blot assay showed that the protein levels of p27(Kip1) and p2l(Cip1) in cells infected with Ad-hTK1 were much more abundant than those in cells only induced by PDGF-BB, with up-modulating rates at 51.8 and 58.7%, respectively (P < 0.001). We also observed that the effects of hTK1 gene delivery in inhibiting VSMCs proliferation, arresting cell cycling in G(0)/G(1) phase and up-regulating the expression of p27(Kip1) and p2l(Cip1) could be blocked by icatibant (Hoe 140), a specific bradykinin B(2) receptor antagonist. Taken together, these results demonstrated that hTK1 overexpressed by recombinant adenovirus potently inhibits VSMCs proliferation that is required for neointimal hyperplasia and restenosis, and may activate p27(Kip1) and p2l(Cip1) signaling pathways via bradykinin B(2) receptor.

E0053 Electroporation-mediated angiotensin II type 2 receptor gene transfected into rat carotid arteries and the effects of AT2R gene transfer on neointimal hyperplasia in rat carotid arteries after balloon angioplasty

AimTo study the effects of Electroporation on the angiotensin II type 2 receptor (AT2R) transfected into rat carotid arteries and study the effects of AT2R gene transfer on neointimal hyperplasia...

Selective phosphodiesterase-5 inhibition reduces neointimal hyperplasia in rat carotid arteries after surgical endarterectomy

Long-term results of surgical vessel reconstruction are compromised by restenosis caused by neointimal hyperplasia. Recent studies suggest that reduced cyclic guanosine monophosphate signaling is associated with neointima formation. In a rat model of endarterectomy, we investigated the effect of pharmacologic inhibition of cyclic guanosine monophosphate degradation on neointima formation by using the selective phosphodiesterase-5 inhibitor vardenafil. Carotid endarterectomy was performed in male Sprague-Dawley rats by means of incision of the right common carotid artery with removal of intima. Four groups were studied: unoperated control rats (n = 4), sham-operated rats (n = 9), control rats with endarterectomy (n = 9), or endarterectomized rats treated with vardenafil (10 mg/kg/day) postoperatively (n = 9). After 3 weeks, vessel compartment areas were measured by means of conventional microscopy with hematoxylin and eosin staining. Immunohistochemical analysis was performed to confirm neointima formation and the local cyclic guanosine monophosphate content. Plasma levels of cyclic guanosine monophosphate were determined by means of enzyme immunoassay. Student's t test was used for statistical evaluation. Immunohistochemical analysis demonstrated intensive staining for transforming growth factor beta1 and alpha-smooth muscle actin in the control neointima. Vardenafil significantly reduced the stenosis grade (24.64% +/- 7.46% vs 54.12% +/- 10.30% in the control group, P < .05) and expression of transforming growth factor beta1, as well as alpha-smooth muscle actin, in the neointima. The immunohistochemical score for cyclic guanosine monophosphate was higher in the treated neointima (4.80 +/- 0.76 vs 2.84 +/- 0.40 in the control group, P < .05), and increased plasma cyclic guanosine monophosphate levels were found by means of enzyme immunoassay as well (84.65 +/- 12.77 pmol/mL vs 43.50 +/- 3.30 pmol/mL in the control group, P < .05). Treatment with vardenafil can be considered a new possibility to prevent neointimal hyperplasia after endarterectomy.

Selective phosphodiesterase-5 inhibition reduces neointimal hyperplasia in rat carotid arteries after surgical endarterectomy

Longterm results of surgical vessel reconstruction are compromised by restenosis due to neointimal hyperplasia. Recent studies suggest that reduced cyclic guanosine monophosphate-signaling is associated with neointima formation. In a rat model of endarterectomy, we investigated the effect of pharmacological inhibition of cyclic guanosine monophosphate-degradation on neointima formation by using the selective phosphodiesterase-5-inhibitor vardenafil.

Effect of Udenafil on Vascular Smooth Muscle Cell Proliferation and Neointimal Hyperplasia in Rat Carotid Artery Injury Model

Background and Objectives: Neointimal hyperplasia, which was caused by smooth muscle cell proliferation, was noted to occur after performing percutaneous coronary intervention. Phosphodiesterase type 5 (PDE5) inhibitor has been shown to inhibit smooth muscle cell proliferation. Udenafil is one of the PDE5 inhibitors, and it is also expected to inhibit smooth muscle cell proliferation and reduce neointimal hyperplasia. We investigated the effect of udenafil on the smooth muscle cell proliferation and neointimal hyperplasia that occurs after balloon injury in the carotid arteries of rats. Materials and Methods: Smooth muscle cells were treated with 1 mM, 100 μM, 10 μM, 1 μM and 100 nM concentrations of udenafil. The viability of the smooth muscle cells was evaluated by MTT assay. The carotid arteries of rats were injured with a balloon catheter. Udenafil (100 μM, 10 μM and 1 μM) was applied on the carotid artery adventitia after balloon injury. At 21 days after treatment, the carotid arteries were harvested and stained with H & E. The neointima and media area were measured with a computerized image analysis program. Results: In the in vitro experiment, treatment with 1 mM udenafil reduced smooth muscle cell viability by 68.8±4.42% compared to the control group. In the balloon injured rat carotid artery, treatment with 100 μM udenafil reduced the neointima area by 71.8% compared to the control group. Conclusion: Udenafil administration effectively inhibited smooth muscle cell proliferation and it reduced neointimal hyperplasia in the balloon-injured rat carotid artery. (Korean Circ J 2008;38:320-324)

Protective Effect of Hydrogen Sulfide on Balloon Injury-Induced Neointima Hyperplasia in Rat Carotid Arteries

Endogenous hydrogen sulfide (H(2)S), generated from homocysteine metabolism mainly catalyzed by cystathionine gamma-lyase (CSE), possesses important functions in the cardiovascular system. In this study, we investigated the role of H(2)S during the pathogenesis of neointimal formation induced by balloon injury in rats. CSE mRNA levels were reduced by 86.5% at 1 week and 64.0% at 4 weeks after balloon injury compared with the uninjured controls. CSE activity was also correspondingly reduced. Endogenous production of H(2)S in the injured carotid artery was significantly inhibited at 1 week and 4 weeks after balloon injury. Treatment with NaHS (a donor of H(2)S) enhanced methacholine-induced vasorelaxation of balloon-injured artery. More importantly, treatment with NaHS significantly inhibited neointima formation (0.15 +/- 0.01 mm(2) versus 0.21 +/- 0.01 mm(2), P < 0.001) of the balloon-injured carotid arteries and reduced the intima/media ratio (1.05 +/- 0.07 versus 1.43 +/- 0.06, P < 0.001). A significant decrease in vascular smooth muscle cell proliferation was demonstrated by bromodeoxyuridine incorporation at day 7 after injury. In conclusion, CSE expression and H(2)S production are reduced during the development of balloon injury-induced neointimal hyperplasia, and treatment with NaHS significantly reduces neointimal lesion formation.

Hepatocyte growth factor suppresses acute renal inflammation by inhibition of endothelial E-selectin

Vascular endothelial activation, marked by de novo expression of E-selectin, is an early and essential event in the process of leukocyte extravasation and inflammation. Evidence suggests that hepatocyte growth factor (HGF) ameliorates inflammation in animal models of renal disease, implying that HGF might inhibit specific components of the inflammatory response. This study examined the effect of HGF on endothelial E-selectin expression in acute inflammation induced by tumor necrosis factor (TNF)-α. In vitro, HGF suppressed TNF-α-induced cell surface expression of E-selectin in human umbilical vein endothelial cells (HUVEC) and inhibited E-selectin mediated monocytic adhesion to endothelial monolayers. HGF activated phosphatidylinositol 3-kinase (PI3K)–Akt that in turn inhibited its downstream transducer glycogen synthase kinase (GSK)3. Blockade of the PI3K–Akt pathway with specific inhibitors abrogated HGF induced inhibitory phosphorylation of GSK3 and suppression of E-selectin. In addition, selective inhibition of GSK3 activity by lithium suppressed TNF-α-induced E-selectin expression and monocytic adhesion, reminiscent of the action of HGF. Moreover, ectopic expression of an uninhibitable mutant GSK3β, in which the regulatory serine-9 is replaced by alanine, abolished HGF's suppressive effect on endothelial E-selectin. In vivo, administration of exogenous HGF reduced endothelial expression of E-selectin induced by bolus injection of TNF-α. This was associated with less sequestration of circulating fluorescence-labeled macrophages in the kidney. These findings suggest that HGF ameliorates acute renal inflammation in part by downregulating E-selectin mediated macrophage adhesion to the inflamed endothelium.

Efficacy of perivascular NO-eluting therapies for the prevention of neointimal hyperplasia

INTRODUCTION: Nitric oxide (NO) has been shown to effectively inhibit neointimal hyperplasia in animal models of arterial injury and vein bypass grafting. However, none of these previous therapies have been deployed in the clinical arena, mostly due to safety concerns, side effects, complexity or lack of significant and durable effect. Recent advances in NO donor chemistry have provided donors with more stable and longer eluting profiles. The aim of this study is to examine the efficacy of two perivascular diazeniumdiolate NO-eluting therapies (PROLIN/NO and PAN/NO) that have clinical potential at inhibiting balloon injury-induced neointimal hyperplasia in rat carotid arteries.

Vitamin D3 exacerbates intimal hyperplasia in balloon-injured arteries.

Although a high dose of vitamin D3 is known to cause arterial calcification and degeneration, its effect on intimal hyperplasia has never been studied. The aim of this study was to examine the influence of a moderate supplement of vitamin D3 on intimal hyperplasia in the balloon-injured rat carotid artery. Forty-four rats had balloon injury to the carotid artery; 22 were given oral vitamin D3 supplementation (0.25 microgram kg-1 day-1). Animals were killed at 4 weeks and the carotid arteries were perfusion fixed and assessed morphometrically by means of computerized image analysis of transverse sections. Mean (s.e.m.) intimal area was significantly greater in the vitamin D3-treated animals than in controls: 0.92(0.05) versus 0.71(0.07) mm2 (P = 0.02). The area of the media of both injured and uninjured arteries was not influenced by vitamin D3 administration. A small dose of vitamin D3 resulted in significant exacerbation of intimal hyperplasia in this rat carotid artery model and raises the question of the role of dietary vitamin D3 in restenosis following vascular intervention.

Role of cimetidine in the prevention of intimal hyperplasia in rat carotid artery.

In vitro studies have revealed that histamine increases smooth muscle cell proliferation and migration, an effect abolished by the H2 antagonist cimetidine. This study examined the effect of cimetidine on intimal hyperplasia in vivo. Thirty male Wistar rats underwent endothelial denudation of the left carotid artery; 15 received cimetidine 350 mg per kg per day for four weeks and 15 received vehicle only. Four weeks after injury the left carotid arteries were perfusion fixed and harvested. Morphometric analysis revealed that there was no significant difference between the intima:media ratio of rats treated with cimetidine (median (interquartile range (i.q.r.)) 1.69 (0.59)) and those treated with vehicle (median (i.q.r.) 1.59 (0.59), P = 0.28). Similarly, the percentage luminal reduction was not significantly different between the groups (median (i.q.r.) 54.7 (19.9) per cent and 45.8 (13.4) per cent respectively, P = 0.30). It is concluded that treatment with cimetidine does not reduce the formation of intimal hyperplasia in rat carotid arteries de-endothelialized with a balloon catheter.

E-selectin blockade decreases adventitial inflammation and attenuates intimal hyperplasia in rat carotid arteries after balloon injury.

Inflammation is one of the initial repair processes after vascular injury. E-selectin facilitates adherence of leukocytes to vascular endothelium at the site of inflammation. Because the role of E-selectin in this process is not fully understood, we studied the role of E-selectin in vascular injury with a flow chamber model and a rat model of carotid artery injury. We established a rat aortic endothelial cell (RAEC) culture system from the aortas of adult male rats. When rat myelomonocytes were suspended in a flow chamber, rolling and adhesion to lipopolysaccharide (LPS)-stimulated RAECs were observed. Cell rolling and adhesion were greatly reduced by addition of anti-E-selectin monoclonal antibody (mAb). We then induced balloon injury in the left carotid arteries of rats. E-selectin expression was enhanced in endothelial cells at adventitial small vessels 7 days after injury. Rats with balloon injury were injected intraperitoneally with anti-E-selectin mAb for 8 days. Inflammatory cell infiltration was reduced by anti-E-selectin mAb treatment at the adventitia at 7 days after injury. This reduction was associated with attenuation of intimal hyperplasia in the rats treated with the mAb. These data suggest that E-selectin regulates adventitial inflammation through leukocyte adhesion and contributes to the process of intimal hyperplasia after balloon injury.

Effects of amrinone, an inhibitor of c-AMP-specific phosphodiesterases, on neointimal hyperplasia after balloon injury in rats

Amrinone(5-amino(3,4'-bibyridin)6-(1H)-one), an inhibitor of c-AMP-specific phosphodiesterases, has been used clinically as an inodilator. We have investigated the effect of amrinone on neointimal hyperplasia in rat carotid artery after balloon injury. When amrinone was administered subcutaneously to rats at a dose of 10 mg/kg/day for 14 days, significant reduction of neointimal thickness was noted. Four days treatment with amrinone, however, failed to reduce the intimal thickness. To investigate the mode of action to reduce intimal thickness, we tried to study the effects of amrinone on platelet aggregation and the proliferation of aortic smooth muscle cells. Amrinone produced a dose-dependent inhibition of ADP-induced rat platelet aggregation in vitro as well as ex vivo in rats. The proliferation of human aortic smooth muscle cells in culture stimulated with FBS or PDGF was also inhibited by amrinone. These results indicate that amrinone may have potential to prevent vascular neointimal hyperplasia in clinical balloon injury through inhibition of vascular smooth muscle cell growth and platelet aggregation.