Ageing-exaggerated proliferation of vascular smooth muscle cells is related to attenuation of Jagged1 expression in endothelial cells

H3K4 Methyltransferase Smyd3 Mediates Vascular Smooth Muscle Cell Proliferation, Migration, and Neointima Formation

[Figure: see text].

3D reconstruction and histopathological analyses on murine corporal body

PURPOSE

Erectile dysfunction (ED) is one of the increasing diseases with aging society. The basis of ED derived from local penile abnormality is poorly understood because of the complex three-dimensional (3D) distribution of sinusoids in corpus cavernosum (CC). Understanding the 3D histological structure of penis is thus necessary. Analyses on the status of regulatory signals for such abnormality are also performed.

METHODS

To analyze the 3D structure of sinusoid, 3D reconstruction from serial sections of murine CC were performed. Histological analyses between young (2 months old) and aged (14 months old) CC were performed. As for chondrogenic signaling status of aged CC, SOX9 and RBPJK staining was examined.

RESULTS

Sinusoids prominently developed in the outer regions of CC adjacent to tunica albuginea. Aged CC samples contained ectopic chondrocytes in such regions. Associating with the appearance of chondrocytes, the expression of SOX9, chondrogenic regulator, was upregulated. The expression of RBPJK, one of the Notch signal regulators, was downregulated in the aged CC.

CONCLUSIONS

Prominent sinusoids distribute in the outer region of CC which may possess important roles for erection. A possibility of ectopic chondrogenesis induced by alteration of SOX9/Notch signaling with aging is indicated.

Decreased Jagged1 expression in vascular smooth muscle cells delays endothelial regeneration in arteriovenous graft

AIMS

It is well-established that endothelial dysfunction promotes activation of vascular smooth muscle cell (VSMC). Whether decreased accumulation of VSMCs affects endothelial regeneration and functions in arteriovenous graft (AVG) remodelling has not been studied. We sought to identify mechanisms by which the Notch ligand, Jagged1, in VSMCs regulates endothelial cell (EC) functions in AVGs.

METHODS AND RESULTS

AVGs were created in transgenic mice bearing VSMC-specific knockout (KO) or overexpression of Jagged1. VSMC migration, EC regeneration, and its barrier functions as well as AVG remodelling were evaluated. Jagged1 expression was induced in VSMCs of neointima in the AVGs. Jagged1 KO in VSMCs inhibited the accumulation of extracellular matrix as well as VSMC migration. Fewer α-SMA-positive VSMCs were found in AVGs created in VSMC-specific Jagged1 KO mice (VSMCJagged1 KO mice) vs. in WT mice. Decreased VSMCs in AVGs were associated with deterioration of EC functions. In AVGs created in transgenic mice bearing Jagged1 KO in VSMCs exhibited delayed EC regeneration and impaired EC barrier function. Barrier dysfunction of ECs increased inflammatory cell infiltration and dysregulation of AVG remodelling and arterialization. The increased expression of IL-1β in macrophages was associated with expression of adhesion markers in ECs in AVGs created in VSMCJagged1 KO mice. In contrast, AVGs created in mice with overexpression of Jagged1 in VSMCs exhibited improved EC regeneration plus decreased macrophage infiltration. This led to AVG remodelling and arterialization. In co-cultures of ECs and VSMCs, Jagged1 deficiency in VSMCs suppressed N-cadherin and integrin β3 expression in ECs. Inhibition of integrin β3 activation delayed EC spreading and migration. Notably, Jagged1 overexpression in VSMCs or treatment with recombinant Jagged1 stimulated the expression of N-cadherin and integrin β3 in ECs. Jagged1-induced responses were blocked by inhibition of Notch signalling.

CONCLUSIONS

Jagged1 expression in VSMCs maintains EC barrier functions and blocks infiltration of macrophages. These responses promote remodelling and arterialization of AVGs.

Role of IGFBP1 in the senescence of vascular endothelial cells and severity of aging‑related coronary atherosclerosis

The senescence of vascular endothelial cells (ECs) plays a critical role in aging-related cardiovascular diseases. We previously reported the causal relation of Jagged1 in ECs and the thickening of the arterial wall in aging mice. The aim of the present study was to further investigate the correlation between insulin-like growth factor-binding protein 1 (IGFBP1), one of the secretory proteins regulated by Jagged1, and the severity of coronary atherosclerosis and patient age, as well as its effect on EC senescence. First, microarray analysis was performed to screen the differentially expressed genes regulated by Jagged1 in human coronary arterial ECs (HCAECs). Inhibition of the Jagged1 expression using a small interfering RNA knockdown method in HCAECs led to the upregulation of 17 and the downregulation of 78 genes by >3-fold, and IGFBP1 was confirmed to be a secretory protein expressed by HCAECs and regulated by Jagged1. Subsequently, in 112 consecutively enrolled patients with acute chest pain who underwent coronary angiography, the circulating level of IGFBP1 was found to be positively correlated with age (r=0.512, P<0.001) and Synergy between PCI with TAXUS and Cardiac Surgery (SYNTAX) score (r=0.409, P<0.001). Among age-comparable patients, the circulating IGFBP1 level was found to be increased in patients with higher SYNTAX scores. In cultured HCAECs, IGFBP1 was shown to protect ECs against passage- or H₂O₂-induced senescence, and these protective effects of IGFBP1 may be partially reversed by LY294002, a known Akt signaling inhibitor. Therefore, the results of the present study suggested that, as a downstream protein of Jagged1, IGFBP1 was correlated with the severity of coronary atherosclerosis in aging patients, and the increase of circulating IGFBP1 levels with aging may be an adaptive response to counter HCAEC senescence through Akt signaling.

Vimentin regulates Notch signaling strength and arterial remodeling in response to hemodynamic stress

The intermediate filament (IF) cytoskeleton has been proposed to regulate morphogenic processes by integrating the cell fate signaling machinery with mechanical cues. Signaling between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) through the Notch pathway regulates arterial remodeling in response to changes in blood flow. Here we show that the IF-protein vimentin regulates Notch signaling strength and arterial remodeling in response to hemodynamic forces. Vimentin is important for Notch transactivation by ECs and vimentin knockout mice (VimKO) display disrupted VSMC differentiation and adverse remodeling in aortic explants and in vivo. Shear stress increases Jagged1 levels and Notch activation in a vimentin-dependent manner. Shear stress induces phosphorylation of vimentin at serine 38 and phosphorylated vimentin interacts with Jagged1 and increases Notch activation potential. Reduced Jagged1-Notch transactivation strength disrupts lateral signal induction through the arterial wall leading to adverse remodeling. Taken together we demonstrate that vimentin forms a central part of a mechanochemical transduction pathway that regulates multilayer communication and structural homeostasis of the arterial wall.

Smooth muscle cell and arterial aging: basic and clinical aspects

Arterial aging engages a plethora of key signalling pathways that act in concert to induce vascular smooth muscle cell (VSMC) phenotypic changes leading to vascular degeneration and extracellular matrix degradation responsible for alterations of the mechanical properties of the vascular wall. This review highlights proof-of-concept examples of components of the extracellular matrix, VSMC receptors which connect extracellular and intracellular structures, and signalling pathways regulating changes in mechanotransduction and vascular homeostasis in aging. Furthermore, it provides a new framework for understanding how VSMC stiffness and adhesion to extracellular matrix contribute to arterial stiffness and how interactions with endothelial cells, platelets, and immune cells can regulate vascular aging. The identification of the key players of VSMC changes operating in large and small-sized arteries in response to increased mechanical load may be useful to better elucidate the causes and consequences of vascular aging and associated progression of hypertension, arteriosclerosis, and atherosclerosis.

The pro-atherogenic response to disturbed blood flow is increased by a western diet, but not by old age

Atherogenic remodeling often occurs at arterial locations with disturbed blood flow (i.e., low or oscillatory) and both aging and western diet (WD) increase the likelihood for pro-atherogenic remodeling. However, it is unknown if old age and/or a WD modify the pro-atherogenic response to disturbed blood flow. We induced disturbed blood flow by partial carotid ligation (PCL) of the left carotid artery in young and old, normal chow (NC) or WD fed male B6D2F1 mice. Three weeks post-PCL, ligated carotid arteries had greater intima media thickness, neointima formation, and macrophage content compared with un-ligated arteries. WD led to greater remodeling and macrophage content in the ligated artery compared with NC mice, but these outcomes were similar between young and old mice. In contrast, nitrotyrosine content, a marker of oxidative stress, did not differ between WD and NC fed mice, but was greater in old compared with young mice in both ligated and un-ligated carotid arteries. In primary vascular smooth muscle cells, aging reduced proliferation, whereas conditioned media from fatty acid treated endothelial cells increased proliferation. Taken together, these findings suggest that the remodeling and pro-inflammatory response to disturbed blood flow is increased by WD, but is not increased by aging.

Beyond cardiomyocyte loss: Role of Notch in cardiac aging

The knowledge of the cellular events occurring in the aging heart has dramatically expanded in the last decade and is expected to further grow in years to come. It is now clear that impaired function and loss of cardiomyocytes are major features of cardiac aging, but other events are likewise important. In particular, accumulating experimental evidence highlights the importance of fibroblast and cardiac progenitor cell (CPC) dysfunction. The Notch pathway regulates cardiomyocyte, fibroblast, and CPC activity and, thus, may be critically involved in heart disease associated with advanced age, especially heart failure. In a translational perspective, thorough investigation of the Notch system in the aging myocardium may lead to the identification of molecular targets for novel therapies for age-related cardiac disease.

Age-related Impairment of Vascular Structure and Functions

Among age-related diseases, cardiovascular and cerebrovascular diseases are major causes of death. Vascular dysfunction is a key characteristic of these diseases wherein age is an independent and essential risk factor. The present work will review morphological alterations of aging vessels in-depth, which includes the discussion of age-related microvessel loss and changes to vasculature involving the capillary basement membrane, intima, media, and adventitia as well as the accompanying vascular dysfunctions arising from these alterations.

Vascular Smooth Muscle Cells and Arterial Stiffening: Relevance in Development, Aging, and Disease

The cushioning function of large arteries encompasses distension during systole and recoil during diastole which transforms pulsatile flow into a steady flow in the microcirculation. Arterial stiffness, the inverse of distensibility, has been implicated in various etiologies of chronic common and monogenic cardiovascular diseases and is a major cause of morbidity and mortality globally. The first components that contribute to arterial stiffening are extracellular matrix (ECM) proteins that support the mechanical load, while the second important components are vascular smooth muscle cells (VSMCs), which not only regulate actomyosin interactions for contraction but mediate also mechanotransduction in cell-ECM homeostasis. Eventually, VSMC plasticity and signaling in both conductance and resistance arteries are highly relevant to the physiology of normal and early vascular aging. This review summarizes current concepts of central pressure and tensile pulsatile circumferential stress as key mechanical determinants of arterial wall remodeling, cell-ECM interactions depending mainly on the architecture of cytoskeletal proteins and focal adhesion, the large/small arteries cross-talk that gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis. We further speculate on the contribution of cellular stiffness along the arterial tree to vascular wall stiffness. In addition, this review provides the latest advances in the identification of gene variants affecting arterial stiffening. Now that important hemodynamic and molecular mechanisms of arterial stiffness have been elucidated, and the complex interplay between ECM, cells, and sensors identified, further research should study their potential to halt or to reverse the development of arterial stiffness.

Trichosanthin attenuates vascular injury-induced neointimal hyperplasia following balloon catheter injury in rats

Trichosanthin (TCS), isolated from the root tuber of Trichosantheskirilowii, a well-known traditional Chinese medicinal plant, belonging to the Cucurbitaceae family, was found to exhibit numerous biological and pharmacological activities including anti-inflammatory. However, the effects of TCS on arterial injury induced neointimal hyperplasia and inflammatory cell infiltration remains poorly understood. The aim of study was to examine the effectiveness of TCS on arterial injury-mediated inflammatory processes and underlying mechanisms. A balloon-injured carotid artery induced injury in vivo in rats was established as a model of vascular injury. After 1 day TCS at 20, 40, or 80 mg/kg/day was administered intraperitoneally, daily for 14 days. Subsequently, the carotid artery was excised and taken for immunohistochemical staining. Data showed that TCS significantly dose-dependently reduced balloon injury-induced neointima formation in the carotid artery model rat, accompanied by markedly decreased positive expression percentage proliferating cell nuclear antigen (PCNA). In the in vitro study vascular smooth muscle cells (VSMC) were cultured, proliferation stimulated with platelet-derived growth factor-BB (PDGF-BB) (20 ng/ml) and TCS at 1, 2, or 4 μM added. Data demonstrated that TCS inhibited proliferation and cell cycle progression of VSMC induced by PDGF-BB. Further, TCS significantly lowered mRNA expression of cyclinD1, cyclinE1, and c-fos, and protein expression levels of Akt1, Akt2, and mitogen-activated protein kinase MAPK (ERK1) signaling pathway mediated by PDGF-BB. These findings indicate that TCS inhibits vascular neointimal hyperplasia induced by vascular injury in rats by suppression of VSMC proliferation and migration, which may involve inhibition of Akt/MAPK/ERK signal pathway.

Role of Delta-like 4 in Jagged1-induced tumour angiogenesis and tumour growth

Delta-like 4 (DLL4) and Jagged1 (JAG1) are two key Notch ligands implicated in tumour angiogenesis. They were shown to have opposite effects on mouse retinal and adult regenerative angiogenesis. In tumours, both ligands are upregulated but their relative effects and interactions in tumour biology, particularly in tumour response to therapeutic intervention are unclear. Here we demonstrate that DLL4 and JAG1 displayed equal potency in stimulating Notch target genes in HMEC-1 endothelial cells but had opposing effects on sprouting angiogenesis in vitro. Mouse DLL4 or JAG1 expressed in glioblastoma cells decreased tumour cell proliferation in vitro but promoted tumour growth in vivo. mDLL4-expressing tumours showed fewer but larger vessels whereas mJAG1-tumours produced more vessels. In both tumour types pericyte coverage was decreased but the vessels were more perfused. Both ligands increased tumour resistance towards anti-VEGF therapy but the resistance was higher in mDLL4-tumours versus mJAG1-tumours. However, their sensitivity to the therapy was restored by blocking Notch signalling with dibenzazepine. Importantly, anti-DLL4 antibody blocked the effect of JAG1 on tumour growth and increased vessel branching in vivo. The mechanism behind the differential responsiveness was due to a positive feedback loop for DLL4-Notch signalling, rendering DLL4 more dominant in activating Notch signalling in the tumour microenvironment. We concluded that DLL4 and JAG1 promote tumour growth by modulating tumour angiogenesis via different mechanisms. JAG1 is not antagonistic but utilises DLL4 in tumour angiogenesis. The results suggest that anti-JAG1 therapy should be explored in conjunction with anti-DLL4 treatment in developing anti-Notch therapies in clinics.

Overexpression of Jagged1 Ameliorates Aged Rat-Derived Endothelial Progenitor Cell Functions and Improves Its Transfusion Efficiency for Rat Balloon-Induced Arterial Injury

BACKGROUND

Endothelial progenitor cell (EPC) has significant age-dependent alterations in properties, but the role of Jagged1 in aging-induced decline of EPC functions remains unclear.

METHODS

2- and 20-month old healthy male Sprague-Dawley rats were used in present study. Jagged1 gene transfection was performed in EPC isolated from aged (AEPC) and young rats (YEPC), respectively. Experiments were divided into 4 groups: (1) pIRES2-EGFP (PE) group, (2) PE-combined N-[N-(3, 5-difluoro-phenacetyl)-1- alany1]-S-phenyglycine t-butyl ester (DAPT) (PE + D) group, (3) pIRES2 EGFP-Jagged1 (PEJ) group, and (4) PEJ combined DAPT (PEJ + D) group. Notch molecules were detected by real-time quantitative polymerase chain reaction or Western blotting. CD34, CD133, CD45, and KDR markers were detected by flow cytometry. EPC migration and proliferation were detected with a modified Boyden chamber and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, respectively; the tube formation ability was assayed by in vitro angiogenesis kit; EPC transfusion after Jagged1 gene transfection was performed in rat carotid artery injury models.

RESULTS

Jagged1 gene transfection effectively activates notch-signaling pathway. Compared with PE groups, overexpression of Jagged1 significantly promoted AEPC functions including proliferation, migration, the tube formation ability, and cell differentiation, these effects could be reasonably diminished by DAPT. In vivo study demonstrated that Jagged1 overexpressing also significantly promoted AEPC homing to the vascular injury sites and decreases the neointima formation after vascular injury.

CONCLUSIONS

Overexpression of Jagged1 ameliorates aged rat-derived EPC functions and increases its transfusion efficiency for balloon-induced rat arterial injury.

Gene Transcriptional and Metabolic Profile Changes in Mimetic Aging Mice Induced by D-Galactose

D-galactose injection has been shown to induce many changes in mice that represent accelerated aging. This mouse model has been widely used for pharmacological studies of anti-aging agents. The underlying mechanism of D-galactose induced aging remains unclear, however, it appears to relate to glucose and 1ipid metabolic disorders. Currently, there has yet to be a study that focuses on investigating gene expression changes in D-galactose aging mice. In this study, integrated analysis of gas chromatography/mass spectrometry-based metabonomics and gene expression profiles was used to investigate the changes in transcriptional and metabolic profiles in mimetic aging mice injected with D-galactose. Our findings demonstrated that 48 mRNAs were differentially expressed between control and D-galactose mice, and 51 potential biomarkers were identified at the metabolic level. The effects of D-galactose on aging could be attributed to glucose and 1ipid metabolic disorders, oxidative damage, accumulation of advanced glycation end products (AGEs), reduction in abnormal substance elimination, cell apoptosis, and insulin resistance.

Age-associated pro-inflammatory remodeling and functional phenotype in the heart and large arteries

The aging population is increasing dramatically. Aging–associated stress simultaneously drives proinflammatory remodeling, involving angiotensin II and other factors, in both the heart and large arteries. The structural remodeling and functional changes that occur with aging include cardiac and vascular wall stiffening, systolic hypertension and suboptimal ventricular-arterial coupling, features that are often clinically silent and thus termed a silent syndrome. These age-related effects are the result of responses initiated by cardiovascular proinflammatory cells. Local proinflammatory signals are coupled between the heart and arteries due to common mechanical and humoral messengers within a closed circulating system. Thus, targeting proinflammatory signaling molecules would be a promising approach to improve age-associated suboptimal ventricular-arterial coupling, a major predisposing factor for the pathogenesis of clinical cardiovascular events such as heart failure.

Hydrogen-rich medium suppresses the generation of reactive oxygen species, elevates the Bcl-2/Bax ratio and inhibits advanced glycation end product-induced apoptosis

The purpose of the present study was to determine whether using hydrogen-rich medium (HRM) to increase hydrogen levels in endothelial cells (ECs) protects ECs from apoptosis induced by advanced glycation end products (AGEs). The thoracic aorta was removed from 2-3-year-old Sprague-Dawley rats, and ECs were isolated and cultured. After culturing ECs in the presence of AGEs and/or with HRM for 24 h, Annexin V/7-AAD and TUNEL staining were carried out to detect apoptosis. Intracellular ROS were detected by fluorescent probe and quantified by flow cytometry. The expression of antioxidative enzymes (superoxide dismutase, glutathione peroxidase) was determined by real-time PCR analysis and enzymatic assay. The relative expression levels of Bcl-2 and Bax were analyzed by western blotting. The addition of AGEs increased the apoptosis of ECs in a concentration-dependent manner and HRM reduced the AGE (400 µg/ml)-induced apoptosis from 21.61±2.52 to 11.32±1.75%. HRM also significantly attenuated the AGE-induced intracellular ROS induction and decrease in the expression of antioxidative enzymes. In conclusion, hydrogen exhibits significant protective effects against AGE-induced EC injury possibly through reducing ROS generation, intracellular antioxidant enzyme system protection and elevation of the Bcl-2/Bax ratio.

Homocysteine activates vascular smooth muscle cells by DNA demethylation of platelet-derived growth factor in endothelial cells

Hyperhomocysteinemia (HHcy), as an independent risk factor of atherosclerosis, facilitates endothelial dysfunction and activation of vascular smooth muscle cells (VSMCs). However, little is known about the crosstalk between endothelial cells (ECs) and VSMCs under HHcy. We investigated whether homocysteine (Hcy) activates VSMCs by aberrant secretion of mitogen platelet-derived growth factors (PDGFs) from ECs in human and in mice. In this study, we found that increased Hcy level did not affect VSMC activity in 24 hrs until the concentration reached 500 μM. In contrast, Hcy at 100 μM significantly promoted proliferation and migration of VSMCs co-cultured with human ECs. This effect was partially reversed by pretreatment with a PDGF receptor inhibitor. Hcy concentration-dependently upregulated the mRNA level of PDGF-A, -C and -D but not PDGF-B in ECs. Hcy reduced the expression and activity of DNA methyltransferase 1, demethylation of PDGF-A, -C and -D promoters and enhanced the binding activity of transcriptional factor SP-1 to the promoter. Hcy upregulation of PDGF was confirmed in the aortic intima of mice with HHcy. Multivariate regression analysis revealed HHcy was a predictor of increased serum PDGF level in patients. Thus, Hcy upregulates PDGF level via DNA demethylation in ECs, affects cross-talk between ECs and VSMCs and leads to VSMC activation.

Ginsenoside Rg1 inhibits vascular intimal hyperplasia in balloon-injured rat carotid artery by down-regulation of extracellular signal-regulated kinase 2

ETHNOPHARMACOLOGICAL RELEVANCE

Ginsenoside Rg1 (Rg1) is one of the main active components of Panax ginseng a well-known herbal medicine. It has been demonstrated to inhibit proliferation of vascular smooth muscle cells (VSMCs) induced by tumor necrosis factor-αin vitro. The present study is aimed to examine the possible effects of Rg1 on vascular neointimal hyperplasia in balloon-injured carotid artery of rats in vivo.

MATERIALS AND METHODS

The animal model was established by rubbing the endothelia with a balloon catheter in the common carotid artery (CCA) of male Sprague Dawley rats. Then the rats were intraperitoneally injected with distilled water in model group and sham operation control, or with Rg1 4, 8 and 16mg/kg/d in other balloon injured groups. After consecutive 14 days, the vascular intimal hyperplasia was evidenced by histopathological alterations of the CCA and by changes observed in the marker of the proliferation of VSMCs-the proliferating cell nuclear antigen (PCNA). The protein expressions of PCNA and the phosphorylated extracellular signal-regulated kinase2 (p-ERK2) as well as mitogen-ativated protein kinase phosphatase-1 (MKP-1) were examined by immunohistochemistry; while the expressions of proto-oncogene (c-fos), ERK2 and smooth muscle α-actin (SM α-actin) mRNA were analyzed by Real-Time RT-PCR.

RESULTS

Rg1 administration could significantly ameliorate the histopathology of CCA and decrease the protein expression of PCNA induced by endothelia rubbing; and Rg1 medication also significantly decreased the expressions of p-ERK2 protein, ERK2 and c-fos mRNA in vessel wall, but up-regulated the MKP-1 expression, which was reported to inactivate mitogen-ativated protein kinase pathway. Furthermore, Rg1 could elevate the decreased SM α-actin mRNA expression induced by balloon injury.

CONCLUSIONS

Rg1 can suppress the vascular neointimal hyperplasia induced by balloon injury, the mechanism may be involved in the inhibition on ERK2 signaling, and related, at least partly, to the increase in MKP-1 expression.

Role of Jagged1 in Arterial Lesions After Vascular Injury

Objective—

Impaired regeneration of endothelial cells (EC) and overactivity of vascular smooth muscle cells (VSMC) are hallmarks of the arterial lesions associated with aging. The occurrence of 2 opposing cellular processes in the same arterial milieu makes pharmaceutical treatment difficult to develop. We previously reported that endothelial expression of a Notch ligand (Jagged1) was reduced in aged animals and that growth of the neointima was enhanced in these animals.

Methods and Results—

Similar to aged animals, Tie2-cre + Jagged1 lox/+ mice (with heterologous knockout of Jagged1 in EC) showed exaggerated intimal and medial thickening after carotid artery ligation. Unexpectedly, these mice showed little increase of Jagged1 expression not only in EC but also in VSMC, in contrast to a significant upregulation of Jagged1 in wild-type arteries after ligation. Coculture of VSMC with Jagged1-null EC resulted in the transition of VSMC from the contractile to the synthetic phenotype, along with decreased Jagged1 expression by VSMC. Conversely, overexpression of Jagged1 by EC or VSMC was shown to prevent the unfavorable phenotypic transition of VSMC, under both monoculture and coculture conditions.

Conclusion—

These findings suggest a unidirectional effect of Jagged1 on both EC and VSMC that contributes to inhibition of arterial lesions after vascular injury. Our data also indicate that Jagged1 may be a novel therapeutic target for aging-related vascular diseases.

Total Ginsenosides suppress the neointimal hyperplasia of rat carotid artery induced by balloon injury

Ginsenosides, the active components found in Panax ginseng, have been reported to inhibit the cardiac hypertrophy in rats. This study aims to observe the potential effect of total ginsenosides (TG) on the hypertrophic vascular diseases. The model of vascular neointimal hyperplasia was established by rubbing the endothelia of the common carotid artery with a balloon in male Sprague Dawley rats. TG (15 mg/kg/day, 45 mg/kg/day), L-arginine (L-arg) 200 mg/kg/day, and NG-nitro-L-arginine-methyl ester (L-NAME) 100 mg/kg/day used with the same dose of L-arg or TG 45 mg/kg/day were given for 7 and 14 consecutive days after surgery. TG and L-arg administrations significantly ameliorated the histopathology of injured carotid artery, which was abolished or blunted by L-NAME, an NOS inhibitor; TG and L-arg could also remarkably reduce the expression of proliferating cell nuclear antigen (PCNA), a proliferation marker of vascular smooth muscle cells(VSMCs), in neointima of the injured artery wall. Further study indicated that balloon injury caused a decreased superoxide dismutase (SOD) activity and an elevated malondialdehyde (MDA) content in plasma, and reduced the cGMP level in the artery wall, which were reversed by TG. It was concluded that TG suppress the rat carotid artery neointimal hyperplasia induced by balloon injury, which may be involved in its anti-oxidative action and enhancing the inhibition effects of NO/cGMP on VSMC proliferation.