Vascular Proliferative Disorders Research Articles

Examination of risk factors for the development of retinopathy in premature children

Introduction/Objective. Retinopathy of prematurity (ROP) is a developmental vascular proliferative disorder in premature children's incompletely vascularized retina. Many factors slow down or prevent the normal development of retinal vascularization in premature babies. The aim of our study was to examine the risk factors in premature infants of gestational age (GA) of 25-36 weeks associated with the occurrence of severe retinopathy of prematurity. Methods. The study was cross-sectional. The research included patients monitored by a screening program for retinopathy of prematurity ie. prematurely born children with a body weight mass (BMW) ? 2000g, and/or GA of ? 36. Results. Statistically significant differences were observed between the ROP and control group in mean values of gestational age, body weight mass (BWM) at birth, Apgar score, and days of oxygen therapy. Also, frequencies of respiratory distress syndrome expression, broncho-pulmonary dysplasia, intraventricular hemorrhages (IVH), and requirement for mechanical ventilation were statistically significantly different between two analyzed groups. Conclusion. Our work confirmed that low GA and low BWM are already accepted risk factors for ROP. The presence of perinatal asphyxia, the length of oxygen administration and assisted ventilation are significantly as-sociated with the appearance of active forms of retinopathy. Sepsis and anemia were shown to be significantly associated with more severe forms of retinopathy, while hyperbilirubinemia was approximately present in both examined groups. More severe forms of IVH and necrotic enterocolitis are significantly more common in children with active retinopathy.

Angiolymphoid Hyperplasia With Temporal Artery Eosinophilia: A Case Report.

Angiolymphoid Hyperplasia with Eosinophilia (ALHE) is a benign vascular proliferative disorder with uncertain etiology and pathogenesis. The aim of this paper is to report a case of ALHE in the temporal artery and discuss the general aspects of this pathology. A 29-year-old female black patient sought the Vascular Surgery Outpatient Service, complaining of bulging in the right temporal region, associated with pain and local discomfort. Physical examination revealed pulsatile bulging in the right temporal region measuring approximately 2.5 × 1.5cm. Nuclear Magnetic Resonance showed an expansive fusiform lesion in the superficial soft parts of the right temporal region, measuring 2.9cm in the longest longitudinal axis. Surgical excision proved to be the best therapeutic option for the patient in this case. Histopathological sections showed the proliferation of vessels of different sizes, covered by swollen endothelium, prominent inflammatory infiltrate composed of lymphocytes, plasma cells, eosinophils, and scarce histiocytes. Immunohistochemical analysis of the lesion showed positivity for CD31, corroborating the diagnosis of ALHE.

Increased Methyl-CpG-Binding Domain Protein 2 Promotes Cigarette Smoke-Induced Pulmonary Hypertension

Pulmonary hypertension (PH) is a chronic vascular proliferative disorder. While cigarette smoke (CS) plays a vital part in PH related to chronic obstructive pulmonary disease (COPD). Methyl-CpG-Binding Domain Protein 2 (MBD2) has been linked to multiple proliferative diseases. However, the specific mechanisms of MBD2 in CS-induced PH remain to be elucidated. Herein, the differential expression of MBD2 was tested between the controls and the PH patients’ pulmonary arteries, CS-exposed rat models’ pulmonary arteries, and primary human pulmonary artery smooth muscle cells (HPASMCs) following cigarette smoke extract (CSE) stimulation. As a result, PH patients and CS-induced rats and HPASMCs showed an increase in MBD2 protein expression compared with the controls. Then, MBD2 silencing was used to investigate the function of MBD2 on CSE-induced HPASMCs’ proliferation, migration, and cell cycle progression. As a consequence, CSE could induce HPASMCs’ increased proliferation and migration, and cell cycle transition, which were suppressed by MBD2 interference. Furthermore, RNA-seq, ChIP-qPCR, and MassARRAY were conducted to find out the downstream mechanisms of MBD2 for CS-induced pulmonary vascular remodeling. Subsequently, RNA-seq revealed MBD2 might affect the transcription of BMP2 gene, which furtherly altered the expression of BMP2 protein. ChIP-qPCR demonstrated MBD2 could bind BMP2’s promotor. MassARRAY indicated that MBD2 itself could not directly affect DNA methylation. In sum, our results indicate that increased MBD2 expression promotes CS-induced pulmonary vascular remodeling. The fundamental mechanisms may be that MBD2 can bind BMP2’s promoter and downregulate its expression. Thus, MBD2 may promote the occurrence of the CS-induced PH.

Screening for Retinopathy of Prematurity Through Utilization a Pediatric Retinal Camera at Jim Pattison Children's Hospital: A Vision for Improved Care.

Retinopathy of Prematurity (ROP) is a vascular proliferative disorder of preterm infants, with increased disease severity and incidence occurring with lower gestational age and birth weight. An alternate approach to ROP screening with wide-field digital retinal imaging helps with the early detection of ROP, especially during the pandemic.

A Review of Proliferative Vascular Disorders of the Central Nervous System of Animals.

In disease, blood vessel proliferation has many salient roles including in inflammation, when granulation tissue fills superficial defects, or in the recanalization of an occluded blood vessel. Sometimes angiogenesis goes awry-granulation can be exuberant, and plexiform proliferation of vascular components can contribute to pulmonary hypertension. This review focuses on the diverse manifestations of pathologic vascular overgrowth that occur in the brain, spinal cord, and meninges of animals from birth until old age. Entities discussed include systemic reactive angioendotheliomatosis in which glomeruloid vascular proliferations are encountered in various organs including the central nervous system (CNS). The triad of CNS vascular malformations, hamartomas, and benign vascular proliferations are an especially fraught category in which terminology overlap and the microscopic similarity of various disorders makes diagnostic classification incredibly challenging. Pathologists commonly take refuge in "CNS vascular hamartoma" despite the lack of any unique histopathologic features and we recommend that this diagnostic category be abandoned. Malformative lesions that are often confusing and have similar features; the conditions include arteriovenous malformation, cavernous angioma, venous angioma, and capillary telangiectases. Meningioangiomatosis, a benign meningovascular proliferation with dual components, is a unique entity seen most commonly in young dogs. Last, accepted neoplastic conditions range from lower-grade locally acquired growths like hemangioblastoma (a tumor of mysterious interstitial stromal cells encountered in the setting of abundant capillary vasculature proliferation), the rare hemangioendothelioma, and the highly malignant and invariably multifocal metastatic hemangiosarcoma. Additionally, this review draws on the comparative medical literature for further insights into this problematic topic in pathology.

Hypoxia Promotes Vascular Smooth Muscle Cell Proliferation through microRNA-Mediated Suppression of Cyclin-Dependent Kinase Inhibitors.

Regulation of vascular smooth muscle cell (VSMC) proliferation is essential to maintain vascular homeostasis. Hypoxia induces abnormal proliferation of VSMCs and causes vascular proliferative disorders, such as pulmonary hypertension and atherosclerosis. As several cyclin/cyclin-dependent kinase (CDK) complexes and CDK inhibitors (CKIs) control cell proliferation, in this study, we investigated CKIs involved in the hypoxia-induced proliferation process of human primary pulmonary artery smooth muscle cells to understand the underlying molecular mechanism. We demonstrated that p15, p16, and p21 are downregulated in pulmonary artery smooth muscle cells when exposed to hypoxia. In addition, we identified novel hypoxia-induced microRNAs (hypoxamiRs) including miR-497, miR-1268a, and miR-665 that are upregulated under hypoxia and post-transcriptionally regulate p15, p16, and p21 genes, respectively, by directly targeting their 3’UTRs. These miRNAs promoted the proliferation of VSMCs, and their inhibition decreased VSMC proliferation even in hypoxic conditions. Overall, this study revealed that miRNA-mediated regulatory mechanism of CKIs is essential for hypoxia-induced proliferation of VSMCs. These findings provide insights for a better understanding of the pathogenesis of vascular proliferative disorders.

The treatment and risk factors of retinopathy of prematurity in neonatal intensive care units

BackgroundRetinopathy of prematurity (ROP) is a vascular proliferative disorder of the developing retina and a significant cause of childhood blindness around the world. The incidence of ROP is affected by many factors, and the incidence rate varies from country to country. The purpose of this study is to report the incidence and risk factors of ROP in neonatal intensive care unit (NICU) of Guangzhou First People’s Hospital in China.MethodsA retrospective review was performed on 436 premature infants who were consecutive ROP screened in the NICU of Guangzhou First People’s Hospital from March 2013 to October 2017. The single-factor analysis and the logistic multivariate regression analysis were used to detect risk factors of ROP.ResultsTotal 436 premature infants were consecutive ROP screened, 138 (31.65%) were found ROP, and 61(13.99%) were treated. The single-factor analysis revealed that the incidence of ROP was associated with multiple births, gestational age, birth weight, mechanical ventilation, intravascular hemolysis, the number of operations and blood culture results. The logistic multivariate regression analysis revealed that gestational age; birth weight, mechanical ventilation, minimum SaO2 and daily weight gain were independent risk factors for ROP onset. Forty-nine patients underwent retinal laser photocoagulation with recurrence 20 patients. Twelve patients underwent anti-VEGF drug (Ranibizumab) via intraocular injection with 5 patients of recurrence.ConclusionsThe incidence of ROP in NICU of Guangzhou China will match those in middle-income countries, but higher than high-income countries. Anti-VEGF drugs could be preferred as a good treatment method for zone 1 ROP and aggressive posterior ROP.

Immunoreactivity of Wilms tumor 1 (WT1) as an additional evidence supporting hemangiomatous rather than inflammatory origin in the etiopathogenesis of angiolymphoid hyperplasia with eosinophilia.

BackgroundAngiolymphoid hyperplasia with eosinophilia (ALHE) is a rare vascular proliferative disorder mainly located in the periauricular region. The etiopathogenesis of ALHE is unknown, and it is still controversial as to whether the entity represents a benign vascular neoplasm or an inflammatory process.AimRecently, the intracytoplasmic staining pattern of Wilms tumor 1 (WT1) on immunohistochemistry has highlighted true vascular neoplasms, such as microvenular hemangioma, tufted angioma, and spindle cell hemangioma, which has made it helpful to distinguish ALHE from vascular malformations, as there is a negative staining pattern in the other entities. We aimed to investigate the immunoreactivity of ALHE specimens for WT1 as well as glucose transporter protein 1 (GLUT1) immunohistochemistry, an important and sensitive marker for the diagnosis of infantile hemangioma, which recently has been described to label other hemangiomas, such as verrucous hemangioma.Material and methodsClinical data and histopathological specimens from patients diagnosed with ALHE were reviewed, and immunohistochemical staining and microscopic analysis for WT-1 and GLUT1 were performed.ResultsIntracytoplasmic endothelial staining of WT1 was detected in 19 of 20 ALHE specimens. GLUT1 was not detected in any ALHE specimen.ConclusionsWe conclude that ALHE may represent a true hemangioma (i.e., benign vascular neoplasia) characterized by an eosinophil- and lymphocyte-rich inflammatory component as opposed to the reactive inflammatory dermatosis with a positive intracytoplasmic staining pattern for WT1. As far as we are aware, WT1 staining for ALHE has not been described to date.

Pharmacological and transcriptional inhibition of the G9a histone methyltransferase suppresses proliferation and modulates redox homeostasis in human microvascular endothelial cells

Epigenetic mechanisms, including histone post-translational modifications, are central regulators of cell cycle control. The euchromatic G9a histone methyltransferase (G9a HMT) is a key enzyme catalyzing histone H3 methylation on lysines 9 and 27, and its dysregulation has been linked to uncontrolled proliferation of tumor cells. Here, we have investigated the effect of G9a HMT silencing on cell proliferation of microvascular endothelial cells, a process necessary to sustain tumor growth through the formation of the vascular capillary network.Inhibition of G9a HMT activity in human microvascular endothelial cells (HMEC-1) was performed either pharmacologically, by treatment of cells with BIX-01294 or chaetocin, or transcriptionally, using shRNA. Cell viability and proliferation were examined using the resazurin reduction assay, flow cytometry and immunostaining of phosphorylated checkpoint kinase 1 (pSer317Chk1). Expression of cell cycle- and redox homeostasis-related genes was determined by quantitative PCR. Reactive oxygen species production was measured by oxidation of the fluorescent probe 2′,7′-dichlorodihydrofluorescein diacetate and the cell’s total antioxidant capacity by using the ABTS assay.Inhibition of G9a HMT activity by BIX-01294 treatment or by shRNA attenuated the proliferation of HMEC-1, nuclear localization of phosphorylated Chk1, and induced cell cycle arrest in G1 phase. Transcriptional analysis demonstrated increased gene expression of the cyclin-dependent kinase (CDK) inhibitor p21, and also of Rb1, in BIX-01294 treated cells. Decreased proliferation rate was accompanied by enhanced antioxidant potential of HMEC-1 cells, as demonstrated by reduced production of reactive oxygen species, increased total antioxidant capacity and expression of the antioxidant enzymes catalase and superoxide dismutase 1.Collectively, our results demonstrate of the central role of G9a HMT in the promotion of endothelial cells proliferation, and suggest that endothelial G9a HMT may be a target in the treatment of vascular proliferative disorders and tumor neovascularization.

MiR-26a contributes to the PDGF-BB-induced phenotypic switch of vascular smooth muscle cells by suppressing Smad1.

The phenotypic switch of vascular smooth muscle cells (VSMCs) is a key event in the pathogenesis of various vascular diseases, such as atherosclerosis and post-angioplasty restenosis. Small non-coding microRNAs (miRNAs) have emerged as critical modulators of VSMC function. In the present study, miR-26a was significantly increased in cultured VSMCs stimulated by platelet-derived growth factor-BB (PDGF-BB) and in arteries with neointimal lesion formation. Moreover, we demonstrated that miR-26a regulates the expression of VSMC differentiation marker genes such as α-smooth muscle actin (α-SMA), calponin and smooth muscle myosin heavy chain (SM-MHC) in PDGF-BB-treated VSMCs. We further confirmed that the regulatory effect of miR-26a during the phenotypic transition occurs through its target gene Smad1, which is a critical mediator of the pro-contractile signal transmitted by bone morphogenetic protein (BMP) and transforming growth factor-beta (TGF-β). This discovery proposed a new channel for communication between PDGF and the BMP/TGF-β family. We concluded that miR-26a is an important regulator in the PDGF-BB-mediated VSMC phenotypic transition by targeting Smad1. Interventions aimed at miR-26a may be promising in treating numerous proliferative vascular disorders.

Long noncoding RNA H19-derived miR-675 aggravates restenosis by targeting PTEN

Restenosis is mainly attributed to excessive proliferation of vascular smooth muscle cells (VSMCs). Noncoding RNAs have been identified as key regulators of diverse pathological processes. We reported that the long noncoding RNA H19 (LncRNA H19) and LncRNA H19-derived microRNA (miR-675) are overexpressed in neointima of balloon-injured artery. Thus, the present study aims to evaluate the role of LncRNA H19 on VSMCs proliferation. To determine the changes of LncRNA H19 and miR-675 expression in the injured arterial wall, the standard rat carotid artery balloon injury model was used. In vivo studies demonstrated that both LncRNA H19 and miR-675 were upregulated after vascular injury. Correlation analysis revealed a positive relationship between LncRNA H19/miR-675 and the ratio of intima to media. Gain-of-function studies showed that the overexpression of LncRNA H19 accelerated T/G HA-VSMC proliferation in vitro. We further validated that PTEN is the target gene of miR-675 as demonstrated by luciferase assay. Finally, the results of the rescue experiment indicated that LncRNA H19 promoted the proliferation of T/G HA-VSMC in a miR-675-dependent manner. This finding not only reveal a novel function of LncRNA H19, but also has important diagnostic and therapeutic implications in the setting of restenosis and perhaps other vascular proliferative disorders as well.

A Decoy Peptide Targeted to Protein Phosphatase 1 Attenuates Degradation of SERCA2a in Vascular Smooth Muscle Cells.

Neointimal growth in the injured vasculature is largely facilitated by the proliferation of vascular smooth muscle cells (VSMC), which associates with reduced sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) activity. The gene transfer-mediated restoration of the SERCA2a level thus attenuates neointimal growth and VSMC proliferation. We previously reported that a peptide targeted to protein phosphatase 1, ψPLB-SE, normalizes SERCA2a activity in cardiomyocytes. In this study, we found that ψPLB-SE attenuated neointimal growth in balloon-injured rat carotid arteries, and the proliferation and migration of VSMC cultured in high-serum media (synthetic conditions). In parallel, ψPLB-SE inhibited the degradation of SERCA2a in the injured carotid arteries and VSMC under synthetic conditions. The calpain inhibitor MDL28170 also attenuated SERCA2a degradation and VSMC proliferation under synthetic conditions, indicating that calpain degrades SERCA2a. The Ca2+ ionophore A23187 induced SERCA2a degradation in VSMC, which was blocked by either ψPLB-SE or MDL28170. Additionally, ψPLB-SE normalized the cytosolic Ca2+ level in VSMC that was increased by either A23187 or synthetic stimulation. Collectively, these data indicate that ψPLB-SE corrects the abnormal Ca2+ handling by activating SERCA2a, which further protects SERCA2a from calpain-dependent degradation in VSMC. We conclude that ψPLB-SE may form the basis of a therapeutic strategy for vascular proliferative disorders.

Analysis of T-786C and 4a/b endothelial nitric oxide synthase gene polymorphisms in retinopathy of prematurity

Retinopathy of prematurity (ROP) is a vascular proliferative disorder of retina, that causes visual impairment in premature children. Beside well known risk factors such as short gestational age, low birth weight and early oxygen exposure, genetic susceptibility is considered as a risk factor for development of the disease. The aim of our study was to explore the association of T-786C and 4a/b eNOS gene polymorphisms with the development of severe ROP. Study included 174 preterm infants, 84 with ROP and 90 as a control group. No differences have been observed in genotypes and alleles distributions of eNOS T-786C and eNOS 4a/b polymorphisms between two analyzed groups. There was significant difference in female infants by dominant model for 4a/b genotypes (4bb/4ba+4aa). Namely, female infants in ROP group were more frequently carriers of 4ba and 4aa genotypes than female infants in control group (p=0.037). Analysis of association between 4a/b eNOS polymorphism and ROP among preterm infants have not shown statistically significant association (p=0.288). Gestational age values by recessive model (4bb+4ba/4aa) were significantly lower in infants with 4aa genotype (t=2.034 p=0.044). Almost all detected 4aa genotypes were present in the group of infants with gestational age under 30 weeks (p=0.032), but multivariate linear regression analysis does not show association of 4a/b genotypes with gestational age of premature infants. According to results of the present study T-786C and 4a/b polymorphisms of the eNOS gene may not be the risk factors for the manifestation of severe ROP in Serbian infants.

Mesoglycan attenuates VSMC proliferation through activation of AMP-activated protein kinase and mTOR.

BackgroundVascular smooth muscle cells (VSMC) proliferation contributes significantly to intimal thickening in atherosclerosis and restenosis diseases. Platelet derived growth factor (PDGF) has been implicated in VSMC proliferation though the activation of multiple growth-promoting signals. Mesoglycan, a natural glycosaminoglycans preparation, is reported to show vascular protective effect. However, the mechanisms by which mesoglycan inhibits proliferation of VSMC are not fully understood. Here, we investigated whether mesoglycan exert therapeutic effect via AMP-activated protein kinase (AMPK) and its underlying mechanism.MethodsWe cultured VSMC with increasing doses of mesoglycan. AMPK activation was measured by western blot analysis and cell proliferation was measured by flow cytometry.ResultsMesoglycan dose- and time- dependently increased the phosphorylation of AMPK (Thr172) and its upstream target, LKB1 (Ser428) and its downstream, ACC (Ser79) in VSMCs. Mesoglycan also blocked the PDGF-stimulated cell cycle progression through the G0/G1 arrest. AMPK DNα1, AMPK DNα2 or AMPK siRNA reduced the mesoglycan-mediated inhibition of VSMC proliferation. AMPK signaling activated by mesoglycan regulates mTOR phosphorylation which closely related to cell proliferation.ConclusionThese data suggest that mesoglycan-induced AMPK activation suppress the VSMC proliferation via mTOR-dependent mechanism and mesoglycan may have beneficial effects on vascular proliferative disorders such as atherosclerosis.

Pseudo-kaposi sarcoma (acroangiodermatitis): occurring after bullous erysipelas

Pseudo-Kaposi sarcoma is a benign reactive vascular proliferative disorder, which can be seen at any age. It occurs when the chronic venous pressure changes result in vascular proliferation in the upper and mid dermis. This disease is divided into two subtypes: the most frequent subtype is the Mali type and seen in early ages. The Mali type is seen in chronic venous insufficiency and in those patients with arteriovenous shunts. The rare subtype is the Stewart-Bluefarb type. This disease must be distinguished from Kaposi sarcoma because of their clinical resemblance. Herein, we present a patient with pseudo-Kaposi sarcoma, which developed after bullous erysipelas.

Identification of PI3K regulatory subunit p55γ as a novel inhibitor of vascular smooth muscle cell proliferation and neointimal formation.

Phosphatidylinositol 3 kinases (PI3Ks) play a pivotal role in vascular physiology and pathophysiology. We aimed to investigate the role of p55γ, a regulatory subunit of PI3Ks, in vascular smooth muscle cell (VSMC) proliferation and neointimal formation. We identified p55γ as an important factor that suppresses VSMC proliferation and injury-evoked neointimal formation. Western blot and mRNA analyses showed that p55γ expression declined in balloon-injured rat carotid arteries and in response to PDGF-BB and serum treatment in cultured VSMCs. Overexpression of p55γ inhibited, whereas short hairpin RNA knockdown of p55γ promoted PDGF-BB- and serum-induced VSMC proliferation. Importantly, in vivo adenoviral gene transfer of p55γ into carotid arteries attenuated, while knockdown of p55γ enhanced balloon injury-induced neointimal formation. Furthermore, p55γ sequentially up-regulated p53 and p21, resulting in cell-cycle arrest in S phase; small-interfering RNA knockdown of either p53 or p21 blocked p55γ-induced VSMC growth arrest. Mechanistically, p55γ interacted with and stabilized p53 protein by blocking mouse double minute 2 homologue-mediated p53 ubiquitination and degradation, subsequently activating its target gene p21. Concurrently, p55γ up-regulated Bcl-xl expression, resulting in non-apoptotic growth arrest effect. These findings mark p55γ as a novel upstream regulator of the p53-p21 signalling pathway that negatively regulates VSMC proliferation, suggesting that malfunction of p55γ may trigger vascular proliferative disorders.

Abstract 338: p55γ Suppresses VSMC Proliferation and Neointimal Formation

Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to various vascular diseases, but the factors that maintain VSMCs in a quiescent state remain poor understood. Phosphatidylinositol 3 kinases (PI3Ks) are important protein kinases that regulate vascular cell proliferation, but the biological and pathological functions of p55γ, a regulatory subunit of PI3K, and its regulation in the cardiovascular system are completely unknown. We aimed to determine the relationship between p55γ and vascular proliferation and neointimal formation. In the present study, we have demonstrated that p55γ expression is markedly downregulated in primary cultured VSMCs in response to mitogenic stimulation and in carotid arteries after balloon injury, and that overexpression p55γ profoundly inhibits mitogenic stimuli and injury induced VSMC proliferation as well as neointimal formation. p55γ overexpression inhibited, whereas knockdown of p55γ promoted PDGF-BB- and serum-induced VSMC proliferation. Importantly, in vivo adenoviral gene transfer of p55γ into carotid arteries attenuated, while knockdown of p55γenhanced balloon injury-induced neointimal formation. Furthermore, p55γ sequentially upregulated p53 and p21, resulting in cell-cycle arrest in S phase; knockdown of either p53 or p21 blocked p55γ-induced VSMC growth arrest. Mechanistically, p55γ interacted with and stabilized p53 protein by blocking MDM2-mediated p53 ubiquitination and degradation, subsequently activating its target gene p21. Concurrently, p55γ upregulated Bcl-xl expression, which counterbalanced p53-mediated apoptosis. These findings mark p55γ as a novel upstream regulator of the p53-p21 signaling pathway which negatively regulates VSMC proliferation, suggesting that malfunction of p55γ may trigger vascular proliferative disorders. * Correspondence to Chun-Mei Cao (caochunmei@pku.edu.cn) or Rui-Ping Xiao (xiaor@pku.edu.cn).

Synergistic Role of Protein Phosphatase Inhibitor 1 and Sarco/Endoplasmic Reticulum Ca 2+ -ATPase in the Acquisition of the Contractile Phenotype of Arterial Smooth Muscle Cells

Phenotypic modulation or switching of vascular smooth muscle cells from a contractile/quiescent to a proliferative/synthetic phenotype plays a key role in vascular proliferative disorders such as atherosclerosis and restenosis. Although several calcium handling proteins that control differentiation of smooth muscle cells have been identified, the role of protein phosphatase inhibitor 1 (I-1) in the acquisition or maintenance of the contractile phenotype modulation remains unknown. In human coronary arteries, I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase expression is specific to contractile vascular smooth muscle cells. In synthetic cultured human coronary artery smooth muscle cells, protein phosphatase inhibitor 1 (I-1 target) is highly expressed, leading to a decrease in phospholamban phosphorylation, sarco/endoplasmic reticulum Ca2+ -ATPase, and cAMP-responsive element binding activity. I-1 knockout mice lack phospholamban phosphorylation and exhibit vascular smooth muscle cell arrest in the synthetic state with excessive neointimal proliferation after carotid injury, as well as significant modifications of contractile properties and relaxant response to acetylcholine of femoral artery in vivo. Constitutively active I-1 gene transfer decreased neointimal formation in an angioplasty rat model by preventing vascular smooth muscle cell contractile to synthetic phenotype change. I-1 and sarco/endoplasmic reticulum Ca2+ -ATPase synergistically induce the vascular smooth muscle cell contractile phenotype. Gene transfer of constitutively active I-1 is a promising therapeutic strategy for preventing vascular proliferative disorders.

Key role of microRNA-15a in the KLF4 suppressions of proliferation and angiogenesis in endothelial and vascular smooth muscle cells

While recent insights indicate that the transcription factor Krüppel-like factor 4 (KLF4) is indispensable for vascular homeostasis, its exact role in proliferation and angiogenesis and how it functions remain unresolved. Thus, the aim of the present study was to evaluate the role of KLF4 in the proliferations of endothelial and vascular smooth muscle cells, as well as the angiogenesis. The overexpression of KLF4 in endothelial cells significantly impaired tube formation. KLF4 inhibited the formation of a vascular network in implanted Matrigel plugs in nude mice. Importantly, we found that KLF4 significantly upregulated the miR-15a expression in endothelial cells and vascular smooth muscle cells, and conversely, KLF4 depletion reduced the amount of miR-15a. Furthermore, KLF4 blocked cell cycle progression and decreased cyclin D1 expression in endothelial cells and vascular smooth muscle cells through the induction of miR-15a. Intriguingly, the delivery of a miR-15a antagomir to nude mice resulted in marked attenuation of the anti-angiogenic effect of KLF4. Collectively, our present study provide the first evidence that miR-15a as a direct transcriptional target of KLF4 that mediates the anti-proliferative and anti-angiogenic actions of KLF4, which indicates that KLF4 upregulation of miR-15a may represent a therapeutic option to suppress proliferative vascular disorders.

Vinpocetine Suppresses Pathological Vascular Remodeling by Inhibiting Vascular Smooth Muscle Cell Proliferation and Migration

Abnormal vascular smooth muscle cell (SMC) activation is associated with various vascular disorders such as atherosclerosis, in-stent restenosis, vein graft disease, and transplantation-associated vasculopathy. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. However, its role in pathological vascular remodeling remains unexplored. Herein, we show that systemic administration of vinpocetine significantly reduced neointimal formation in carotid arteries after ligation injury. Vinpocetine also markedly decreased spontaneous remodeling of human saphenous vein explants in ex vivo culture. In cultured SMCs, vinpocetine dose-dependently suppressed cell proliferation and caused G1-phase cell cycle arrest, which is associated with a decrease in cyclin D1 and an increase in p27Kip1 levels. In addition, vinpocetine dose-dependently inhibited platelet-derived growth factor (PDGF)-stimulated SMC migration as determined by the two-dimensional migration assays and three-dimensional aortic medial explant invasive assay. Moreover, vinpocetine significantly reduced PDGF-induced type I collagen and fibronectin expression. It is noteworthy that PDGF-stimulated phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), but not protein kinase B, was specifically inhibited by vinpocetine. Vinpocetine powerfully attenuated intracellular reactive oxidative species (ROS) production, which largely mediates the inhibitory effects of vinpocetine on ERK1/2 activation and SMC growth. Taken together, our results reveal a novel function of vinpocetine in attenuating neointimal hyperplasia and pathological vascular remodeling, at least partially through suppressing ROS production and ERK1/2 activation in SMCs. Given the safety profile of vinpocetine, this study provides insight into the therapeutic potential of vinpocetine in proliferative vascular disorders.