M Kearney

St. Elizabeth's Medical Center, Boston, Massachusetts, United States

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Publications (86)845.73 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: The adhesion integrin αvβ3 is expressed by both activated endothelial cells (ECs) and smooth muscle cells (SMCs). Peptide and antibody antagonists of αvβ 3 have been shown to block angiogenesis by initiating unscheduled programmed cell death of proliferating ECs. The present study was designed to determine if antagonism of αvβ 3 immediately following balloon injury might similarly lead to programmed cell death among activated SMCs, and thereby inhibit intimal thickening. LM609, a monoclonal antibody antagonist of αvβ 3, was administered locally and/or systemically immediately after balloon angioplasty in a rabbit model of vascular injury. Immunohistochemical studies documented that LM609, even when administered systemically, localized to sites of vascular injury. LM609 administered immediately following balloon injury of the external iliac artery markedly reduced intimal thickening at 2 and 4 wk post-injury. Apoptosis was abundant where balloon injury resulted in expression of αvβ 3. At both 2 and 4wk, re-endothelialization at the site of balloon injury was not retarded in LM609-treated rabbits versus controls. Thus, blockade of αvβ 3 inhibits intimal thickening when administered immediately following balloon injury. This favorable impact on neointimal thickening is associated with apoptosis of activated SMCs expressing αvβ 3. These findings may explain the reduction in restenosis observed clinically following,93 integrin blockade.
    08/2009; 6(5):371-379.
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    ABSTRACT: Expression of angiogenic cytokines like vascular endothelial growth factor is enhanced by hypoxia. We tested the hypothesis that decreased oxygen levels up-regulate the angiogenic factor secretoneurin. In vivo, muscle cells of mouse ischemic hind limbs showed increased secretoneurin expression, and inhibition of secretoneurin by a neutralizing antibody impaired the angiogenic response in this ischemia model. In a mouse soft tissue model of hypoxia, secretoneurin was increased in subcutaneous muscle fibers. In vitro, secretoneurin mRNA and protein were up-regulated in L6 myoblast cells after exposure to low oxygen levels. The hypoxia-dependent regulation of secretoneurin was tissue specific and was not observed in endothelial cells, vascular smooth muscle cells, or AtT20 pituitary tumor cells. The hypoxia-dependent induction of secretoneurin in L6 myoblasts is regulated by hypoxia-inducible factor-1alpha, since inhibition of this factor using si-RNA inhibited up-regulation of secretoneurin. Induction of secretoneurin by hypoxia was dependent on basic fibroblast growth factor in vivo and in vitro, and inhibition of this regulation by heparinase suggests an involvement of low-affinity basic fibroblast growth factor binding sites. In summary, our data show that the angiogenic cytokine secretoneurin is up-regulated by hypoxia in muscle cells by hypoxia-inducible factor-1alpha- and basic fibroblast growth factor-dependent mechanisms.
    The FASEB Journal 10/2007; 21(11):2906-17. · 5.70 Impact Factor
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    ABSTRACT: A growing population of patients with coronary artery disease experiences angina that is not amenable to revascularization and is refractory to medical therapy. Preclinical studies have indicated that human CD34+ stem cells induce neovascularization in ischemic myocardium, which enhances perfusion and function. Twenty-four patients (19 men and 5 women aged 48 to 84 years) with Canadian Cardiovascular Society class 3 or 4 angina who were undergoing optimal medical treatment and who were not candidates for mechanical revascularization were enrolled in a double-blind, randomized (3:1), placebo-controlled dose-escalating study. Patients received granulocyte colony-stimulating factor 5 microg x kg(-1) x d(-1) for 5 days with leukapheresis on the fifth day. Selection of CD34+ cells was performed with a Food and Drug Administration-approved device. Electromechanical mapping was performed to identify ischemic but viable regions of myocardium for injection of cells (versus saline). The total dose of cells was distributed in 10 intramyocardial, transendocardial injections. Patients were required to have an implantable cardioverter-defibrillator or to temporarily wear a LifeVest wearable defibrillator. No incidence was observed of myocardial infarction induced by mobilization or intramyocardial injection. The intramyocardial injection of cells or saline did not result in cardiac enzyme elevation, perforation, or pericardial effusion. No incidence of ventricular tachycardia or ventricular fibrillation occurred during the administration of granulocyte colony-stimulating factor or intramyocardial injections. One patient with a history of sudden cardiac death/ventricular tachycardia/ventricular fibrillation had catheter-induced ventricular tachycardia during mapping that required cardioversion. Serious adverse events were evenly distributed. Efficacy parameters including angina frequency, nitroglycerine usage, exercise time, and Canadian Cardiovascular Society class showed trends that favored CD34+ cell-treated patients versus control subjects given placebo. A randomized trial of intramyocardial injection of autologous CD34+ cells in patients with intractable angina was completed that provides evidence for feasibility, safety, and bioactivity. A larger phase IIb study is currently under way to further evaluate this therapy.
    Circulation 07/2007; 115(25):3165-72. · 15.20 Impact Factor
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    ABSTRACT: We compared the therapeutic potential of purified mobilized human CD34+ cells with that of mobilized total mononuclear cells (tMNCs) for the preservation/recovery of myocardial tissue integrity and function after myocardial infarction (MI). CD34+ cells were purified from peripheral blood tMNCs of healthy volunteers by magnetic cell sorting after a 5-day administration of granulocyte colony-stimulating factor. Phosphate-buffered saline (PBS), 5x10(5) CD34+ cells/kg, 5x10(5) tMNCs/kg (low-dose MNCs [loMNCs]), or a higher dose of tMNCs (hiMNCs) containing 5x10(5) CD34+ cells/kg was transplanted intramyocardially 10 minutes after the induction of MI in athymic nude rats. Hematoxylin and eosin staining revealed that moderate to severe hemorrhagic MI on day 3 was more frequent in the hiMNC group than in the PBS and CD34+ cell groups. Immunostaining for human-specific CD45 revealed abundant distribution of hematopoietic/inflammatory cells derived from transplanted cells in the ischemic myocardium of the hiMNC group. Capillary density on day 28 was significantly greater in the CD34+ cell group (721.1+/-19.9 per 1 mm2) than in the PBS, loMNC, and hiMNC groups (384.7+/-11.0, 372.5+/-14.1, and 497.5+/-24.0 per 1 mm2) (P<0.01). Percent fibrosis area on day 28 was less in the CD34(+) cell group (15.6+/-0.9%) than in the PBS, loMNC, and hiMNC groups (26.3+/-1.2%, 27.5+/-1.8%, and 22.2+/-1.8%) (P<0.05). Echocardiographic fractional shortening on day 28 was significantly higher in the CD34+ cell group (30.3+/-0.9%) than in the PBS, loMNC, and hiMNC groups (22.7+/-1.5%, 23.4+/-1.1%, and 24.9+/-1.7%; P<0.05). Echocardiographic regional wall motion score was better preserved in the CD34+ cell group (21.8+/-0.5) than in the PBS, loMNC, and hiMNC groups (25.4+/-0.4, 24.9+/-0.4, and 24.1+/-0.6; P<0.05). CD34+ cells exhibit superior efficacy for preserving myocardial integrity and function after MI than unselected circulating MNCs.
    Circulation 11/2006; 114(20):2163-9. · 15.20 Impact Factor
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    ABSTRACT: Information on the safety of mobilization and collection of peripheral blood progenitor cells (PBPC) in patients with advanced coronary heart disease (CHD) is limited. We report herein our early experience with patients participating in a Phase I trial of injection of autologous CD 34(+) cells into threatened, ischemic myocardium for neovascularization and symptom relief in patients with chronic refractory myocardial ischemia. All patients had advanced inoperable CHD despite the best medical therapy. Granulocyte colony stimulating factor (G-CSF, 5 microg/kg/day) was administered subcutaneously for 5 days for mobilization of CD34(+) cells into the peripheral blood. PBPCs were collected in the outpatient apheresis suite on day 5. Nine patients from our institution were evaluable. Adverse effects of mobilization included: increase in frequency and/or intensity of angina in 8 patients (88.8%); bone pain in 7 patients (77.7%); headaches in 4 patients (44.4%); 2 patients (22%) were hospitalized. Collection phase toxicities included: tingling in 5 patients (55.5%) and angina in 3 patients (33%). All procedures were completed without new myocardial infarction, congestive heart failure, or death. The median peripheral blood CD34(+) cell count on day 5 of G-CSF was 21 cells/microl (range 10-40 cells/microl). A median of 1.65 x 10(6) CD34(+) cells/kg (range: 0.13-3.0 x 10(6)/kg) were harvested. We conclude that mobilization and collection of PBPC in patients with advanced CHD can be safely performed as an outpatient procedure. Apheresis professionals should be aware of the intensity and frequency of angina in this patient population.
    Journal of Clinical Apheresis 08/2006; 21(2):116-20. · 2.27 Impact Factor
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    ABSTRACT: The transcription factor E2F1 is known to regulate cell proliferation and has been thought to modulate tumorigenesis via this mechanism alone. Here we show that mice deficient in E2F1 exhibit enhanced angiogenesis. The proangiogenic phenotype in E2F1 deficiency is the result of overproduction of vascular endothelial growth factor (VEGF) and is prevented by VEGF blockade. Under hypoxic conditions, E2F1 down-regulates the expression of VEGF promoter activity by associating with p53 and specifically down-regulating expression of VEGF but not other hypoxia-inducible genes, suggesting a promoter structure context-dependent regulation mechanism. We found that the minimum VEGF promoter mediating transcriptional repression by E2F1 features an E2F1- binding site with four Sp-1 sites in close proximity. These data disclose an unexpected function of endogenous E2F1: regulation of angiogenic activity via p53-dependent transcriptional control of VEGF expression.
    Proceedings of the National Academy of Sciences 08/2006; 103(29):11015-20. · 9.74 Impact Factor
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    ABSTRACT: Previous studies have shown that local angiogenic gene therapy acts, in part, by recruiting endothelial progenitor cells (EPCs) to ischemic tissue. Recent data indicate that patients with the most severe vascular disease may have insufficient or deficient EPCs and the poorest response to angiogenic therapy. Accordingly, we hypothesized that combining human CD34(+) cell implantation with local vascular endothelial growth factor 2 (phVEGF2) gene therapy might overcome these deficiencies. The addition of VEGF2 to EPC cultures resulted in significant and dose-dependent decreases in EPC apoptosis. Phosphorylated Akt (p-Akt) was increased in VEGF2-treated EPCs. In vivo, myocardial infarction (MI) was induced by ligation of the left anterior descending coronary artery in 34 immunodeficient rats. The animals were then randomized to one of four treatment groups: cell therapy alone with human CD34(+) cells; VEGF2 gene therapy alone; combination therapy with CD34(+) cells plus phVEGF2; or CD34(-) cells and 50 microg empty plasmid. Four weeks after MI, animals treated with combination therapy showed improved fractional shortening, increased capillary density, and reduced infarct size compared with the other three groups. Combination therapy was also associated with an increased number of circulating EPCs 1 week after MI. Combined subtherapeutic doses of cell and gene therapy result in a significant therapeutic effect compared to monotherapy. This approach may overcome therapeutic failures (e.g. inability of certain patients to mobilize sufficient EPCs) and may also offer safety advantages by allowing lower dosing strategies.
    Nature Clinical Practice Cardiovascular Medicine 04/2006; 3 Suppl 1:S123-8. · 7.04 Impact Factor
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    ABSTRACT: The cell surface receptor alpha4 integrin plays a critical role in the homing, engraftment, and maintenance of hematopoietic progenitor cells (HPCs) in the bone marrow (BM). Down-regulation or functional blockade of alpha4 integrin or its ligand vascular cell adhesion molecule-1 mobilizes long-term HPCs. We investigated the role of alpha4 integrin in the mobilization and homing of BM endothelial progenitor cells (EPCs). EPCs with endothelial colony-forming activity in the BM are exclusively alpha4 integrin-expressing cells. In vivo, a single dose of anti-alpha4 integrin antibody resulted in increased circulating EPC counts for 3 d. In hindlimb ischemia and myocardial infarction, systemically administered anti-alpha4 integrin antibody increased recruitment and incorporation of BM EPCs in newly formed vasculature and improved functional blood flow recovery and tissue preservation. Interestingly, BM EPCs that had been preblocked with anti-alpha4 integrin ex vivo or collected from alpha4 integrin-deficient mice incorporated as well as control cells into the neovasculature in ischemic sites, suggesting that alpha4 integrin may be dispensable or play a redundant role in EPC homing to ischemic tissue. These data indicate that functional disruption of alpha4 integrin may represent a potential angiogenic therapy for ischemic disease by increasing the available circulating supply of EPCs.
    Journal of Experimental Medicine 02/2006; 203(1):153-63. · 13.21 Impact Factor
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    ABSTRACT: Sonic hedgehog (Shh) is a crucial regulator of organ development during embryogenesis. We investigated whether intramyocardial gene transfer of naked DNA encoding human Shh (phShh) could promote a favorable effect on recovery from acute and chronic myocardial ischemia in adult animals, not only by promoting neovascularization, but by broader effects, consistent with the role of this morphogen in embryogenesis. After Shh gene transfer, the hedgehog pathway was upregulated in mammalian fibroblasts and cardiomyocytes. This resulted in preservation of left ventricular function in both acute and chronic myocardial ischemia by enhanced neovascularization, and reduced fibrosis and cardiac apoptosis. Shh gene transfer also enhanced the contribution of bone marrow-derived endothelial progenitor cells to myocardial neovascularization. These data suggest that Shh gene therapy may have considerable therapeutic potential in individuals with acute and chronic myocardial ischemia by triggering expression of multiple trophic factors and engendering tissue repair in the adult heart.
    Nature Medicine 12/2005; 11(11):1197-204. · 22.86 Impact Factor
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    ABSTRACT: Hyperhomocyst(e)inemia (HH) is an established independent risk factor for coronary, cerebral and peripheral vascular diseases. Recent studies have indicated that certain cardiovascular risk factors, including diabetes and hypercholesterolemia, impair expression of vascular endothelial growth factor (VEGF) and endogenous angiogenesis. In this study, we investigate the impact of moderate HH on angiogenesis and VEGF pathway in a mouse model of hindlimb ischemia. Upon induction of unilateral hindlimb ischemia, endogenous angiogenesis, expression of VEGF, and phosphorylation of the VEGF receptor Flk-1 were evaluated in mice heterozygous for a deletion of the cystathionine beta-synthase gene (CBS) and compared with those observed in CBS+/+ mice. CBS+/- mice exhibit moderate HH, as demonstrated by measuring plasma total homocyst(e)ine (tHcy) levels, which were significantly higher in these animals compared with CBS+/+ mice (4.77 +/- 0.82 vs 2.10 +/- 0.28, p < 0.01). Twenty-eight days after induction of ischemia, hindlimb blood flow was significantly reduced in CBS+/- mice compared with CBS+/+ animals (0.49 +/- 0.03, n = 12 vs 0.71 +/- 0.09, n = 10; p < 0.05). In addition, there was a significant negative correlation between plasma homocyst(e)ine levels and the laser Doppler perfusion ratio in CBS+/- mice (p = 0.0087, r = -0.7171). While VEGF expression and Flk-1 phosphorylation were not impaired in the ischemic muscles of CBS+/- mice, phosphorylation of the endothelial cell survival factor Akt was significantly inhibited by homocyst(e)ine in a dose-dependent manner in human umbilical vein endothelial cell (HUVECs) in vitro. In conclusion, our findings demonstrate that endogenous angiogenesis is inversely related to plasma levels of homocyst(e)ine in genetically engineered, heterozygous mice with moderate HH. This impairment, however, is not dependent on reduced expression of VEGF or impaired phosphorylation of its receptor Flk-1. In contrast, our data suggest that impaired Akt phosphorylation mediates the impairment of angiogenesis associated with HH.
    Vascular Medicine 03/2005; 10(1):15-22. · 1.62 Impact Factor
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    ABSTRACT: The embryonic morphogen sonic hedgehog (SHh) has been shown to induce neovascularization of ischemic tissue but has not been shown to play a role in regulating vascular nerve supply. Accordingly, we investigated the hypothesis that systemic injection of SHh protein could improve nerve blood flow and function in diabetic neuropathy (DN). Twelve weeks after induction of diabetes with streptozotocin, motor and sensory nerve conduction velocities (MCV and SCV) of the sciatic nerves were significantly reduced in diabetic rats. SHh-treated diabetic rats demonstrated marked improvement of both MCV and SCV (P<0.05). Laser Doppler perfusion imaging showed that nerve blood flow was significantly reduced in the diabetic rats but was restored in SHh-treated diabetic rats (P<0.05 versus diabetic saline-treated rats) to levels similar to those achieved with vascular endothelial growth factor-2 (VEGF-2) gene therapy. In vivo perfusion of Bandeuraea simplicifolia (BS)-1 lectin showed marked reduction in the vasa nervora in diabetic sciatic nerves but restoration of nerve vasculature to nondiabetic levels in the SHh-treated and plasmid DNA encoding human VEGF-2 (phVEGF-2)-treated diabetic nerves. Interestingly, the SHh-induced vasculature was characterized by larger diameter and more smooth muscle cell-containing vessels, compared with VEGF-2 gene-treated diabetic rats. These data indicate that Shh induces arteriogenesis and restores nerve function in DN.
    Arteriosclerosis Thrombosis and Vascular Biology 12/2004; 24(11):2102-7. · 6.34 Impact Factor
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    ABSTRACT: We performed a series of investigations to test the hypothesis that combining angiogenic gene therapy and cytokine (CK)-induced endothelial progenitor cell mobilization would be superior to either strategy alone for treatment of chronic myocardial ischemia. A swine model of chronic myocardial ischemia and a murine model of acute myocardial infarction were used in this study. In both models, animals were randomly assigned to 1 of 4 treatment groups: Combo group, intramyocardial vascular endothelial growth factor (VEGF)-2 gene transfer plus subcutaneous injection of CKs; VEGF-2, VEGF-2 gene transfer plus saline subcutaneously injected; CK, empty vector transfer plus CKs; and control, empty vector plus subcutaneous saline. Acute myocardial infarction was also induced in wild-type mice 4 weeks after bone marrow transplantation from enhanced green fluorescent protein transgenic mice to permit observation of bone marrow-derived cells in the myocardium after acute myocardial infarction. In chronic myocardial ischemia, combination therapy resulted in superior improvement in all indexes of perfusion and function compared with all other treatment groups. In the bone marrow transplant mice, double immunofluorescent staining revealed that the combination of CK-induced mobilization and local VEGF-2 gene transfer resulted in a significant increase in the number of bone marrow-derived cells incorporating into the neovasculature, indicating that recruitment and/or retention of bone marrow-derived progenitors was enhanced by mobilization and that local VEGF-2 gene transfer can provide signals for recruitment or incorporation of circulating progenitor cells. Mobilization of endothelial progenitor cells with cytokines potentiates VEGF-2 gene therapy for myocardial ischemia and enhances bone marrow cell incorporation into ischemic myocardium.
    Circulation 10/2004; 110(11):1398-405. · 15.20 Impact Factor
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    ABSTRACT: Drug-eluting stents represent a useful strategy for the prevention of restenosis using various antiproliferative drugs. These strategies share the liability of impairing endothelial recovery, thereby altering the natural biology of the vessel wall and increasing the associated risk of stent thrombosis. Accordingly, we tested the hypothesis that local delivery via gene-eluting stent of naked plasmid DNA encoding for human vascular endothelial growth factor (VEGF)-2 could achieve similar reductions in neointima formation while accelerating, rather than inhibiting, reendothelialization. phVEGF 2-plasmid (100 or 200 microg per stent)-coated BiodivYsio phosphorylcholine polymer stents versus uncoated stents were deployed in a randomized, blinded fashion in iliac arteries of 40 normocholesterolemic and 16 hypercholesterolemic rabbits. Reendothelialization was nearly complete in the VEGF stent group after 10 days and was significantly greater than in control stents (98.7+/-1% versus 79.0+/-6%, P<0.01). At 3 months, intravascular ultrasound analysis revealed that lumen cross-sectional area (4.2+/-0.4 versus 2.27+/-0.3 mm(2), P<0.001) was significantly greater and percent cross-sectional narrowing was significantly lower (23.4+/-6 versus 51.2+/-10, P<0.001) in VEGF stents compared with control stents implanted in hypercholesterolemic rabbits. Transgene expression was detectable in the vessel wall along with improved functional recovery of stented segments, resulting in a 2.4-fold increase in NO production. Acceleration of reendothelialization via VEGF-2 gene-eluting stents provides an alternative treatment strategy for the prevention of restenosis. VEGF-2 gene-eluting stents may be considered as a stand-alone or combination therapy.
    Circulation 07/2004; 110(1):36-45. · 15.20 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2004; 43(5).
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    ABSTRACT: We hypothesized that estrogen-induced acceleration of reendothelialization might be mediated in part by effects involving mobilization and incorporation of bone marrow-derived endothelial progenitor cells (EPCs). Carotid injury was induced in ovariectomized wild-type mice receiving either 17beta-estradiol or placebo. Estradiol treatment significantly accelerated reendothelialization of injured arterial segments within 7 days and resulted in a significant reduction of medial thickness 14 and 21 days after the injury. Significant increases in circulating EPCs 3 days after the injury were observed in the estradiol group compared with placebo-treated mice. These data were further supported by fluorescence-activated cell sorting analysis, which disclosed a significant increase in Sca-1/Flk-1-positive cells in estradiol versus control mice. To evaluate the effects of estradiol on bone marrow-derived EPC incorporation at sites of reendothelialization, carotid injury was established in ovariectomized wild-type mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the Tie-2 promoter. Significantly greater numbers of X-gal-positive cells were observed at reendothelialized areas in the estradiol group 3 days after injury as compared with placebo. Fluorescent immunohistochemistry 14 days after the injury documented a marked increase in cells expressing both beta-gal, indicating bone marrow origin and Tie-2 expression, and isolectin B4, also indicating endothelial lineage, in the estradiol group compared with control. In contrast, estradiol did not accelerate reendothelialization or augment EPC mobilization into the peripheral circulation after injury in endothelial nitric oxide synthase-deficient mice (eNOS-/-). Furthermore, estradiol exhibited direct stimulatory effects on EPC mitogenic and migration activity and inhibited EPC apoptosis. Estradiol accelerates reendothelialization and attenuates medial thickening after carotid injury in part by augmenting mobilization and proliferation of bone marrow-derived EPCs and their incorporation into the recovering endothelium at the site of injury.
    Circulation 01/2004; 108(25):3115-21. · 15.20 Impact Factor
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    ABSTRACT: Hedgehog (Hh) proteins are morphogens regulating epithelial-mesenchymal signaling during several crucial processes of embryonic development, including muscle patterning. Sonic (Shh), Indian (Ihh), and Desert (Dhh) hedgehog constitute the repertoire of Hh genes in humans. The activities of all 3 are transduced via the Patched (Ptc1) receptor. Recent observations indicate that exogenous administration of Shh induces angiogenesis. Here, we studied whether the endogenous Hh pathway, in addition to its functions during embryogenesis, plays a physiological role in muscle regeneration after ischemia in adults. We found that skeletal muscle ischemia induces strong local upregulation of Shh mRNA and protein. In addition, the Ptc1 receptor is activated in interstitial mesenchymal cells within the ischemic area, indicating that these cells respond to Shh and that the Shh pathway is functional. We also found that Shh-responding cells produce vascular endothelial growth factor under ischemic conditions and that systemic treatment with a Shh-blocking antibody inhibits the local angiogenic response and the upregulation of vascular endothelial growth factor. Our study shows that the Hh signaling may be recapitulated postnatally in adult and fully differentiated muscular tissues and has a regulatory role on angiogenesis during muscle regeneration after ischemia. These findings demonstrate a novel biological activity for the Hh pathway with both fundamental and potential therapeutic implications.
    Circulation 08/2003; 108(4):479-85. · 15.20 Impact Factor
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    ABSTRACT: Tumor necrosis factor-alpha (TNF-alpha) is expressed locally in the vessel wall after angioplasty and induces growth arrest and apoptosis in endothelial cells (ECs), thereby delaying reendothelialization. Prior studies have shown that direct antagonism of TNF-alpha, using a systemically administered soluble receptor, can enhance endothelial recovery and reduce neointimal thickening. These studies have also shown that downregulation of the transcription factor E2F1 was a key mechanism of TNF's effect on ECs. We now show that Ad-E2F1 overexpression at sites of balloon injury accelerates functional endothelial recovery, consistent with the prior in vitro findings. Moreover these studies also reveal divergent effects of TNF-alpha and overexpression of E2F1 on ECs versus VSMCs. TNF-alpha exposure of VSMCs had no affect on proliferation or apoptosis, in contrast to the effect seen in ECs. In Ad-E2F1-transduced VSMCs, however, TNF-alpha-induced marked apoptosis in contrast to the survival effect seen in ECs. Finally, these studies suggest that differential activation of NF-kappaB may play a key role in mediating these opposing effects. Nuclear translocation and transcriptional activity of NF-kappaB was markedly attenuated in Ad-E2F1-transduced VSMCs, whereas it remained active in similarly treated ECs when the cells were exposed to TNF-alpha. These studies reveal that overexpression of Ad-E2F1 primes VSMCs to TNF-alpha-induced apoptosis. Furthermore, E2F1 potentiates VSMC death by blocking antiapoptotic signaling pathway through inhibition of NF-kappaB activation. The divergent responses of VSMCs and ECs to E2F1 overexpression provide unique therapeutic possibilities: simultaneously targeting the cell cycle of two different cell types, within same tissue microenvironment resulting in opposite and biologically complimentary effects.
    Circulation Research 08/2003; 93(2):162-9. · 11.86 Impact Factor
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    ABSTRACT: Although lymphedema is a common clinical condition, treatment for this disabling condition remains limited and largely ineffective. Recently, it has been reported that overexpression of VEGF-C correlates with increased lymphatic vessel growth (lymphangiogenesis). However, the effect of VEGF-C-induced lymphangiogenesis on lymphedema has yet to be demonstrated. Here we investigated the impact of local transfer of naked plasmid DNA encoding human VEGF-C (phVEGF-C) on two animal models of lymphedema: one in the rabbit ear and the other in the mouse tail. In a rabbit model, following local phVEGF-C gene transfer, VEGFR-3 expression was significantly increased. This gene transfer led to a decrease in thickness and volume of lymphedema, improvement of lymphatic function demonstrated by serial lymphoscintigraphy, and finally, attenuation of the fibrofatty changes of the skin, the final consequences of lymphedema. The favorable effect of phVEGF-C on lymphedema was reconfirmed in a mouse tail model. Immunohistochemical analysis using lymphatic-specific markers: VEGFR-3, lymphatic endothelial hyaluronan receptor-1, together with the proliferation marker Ki-67 Ab revealed that phVEGF-C transfection potently induced new lymphatic vessel growth. This study, we believe for the first time, documents that gene transfer of phVEGF-C resolves lymphedema through direct augmentation of lymphangiogenesis. This novel therapeutic strategy may merit clinical investigation in patients with lymphedema.
    Journal of Clinical Investigation 04/2003; 111(5):717-25. · 12.81 Impact Factor
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    ABSTRACT: We investigated whether catheter-based, intramyocardial transplantation of autologous endothelial progenitor cells can enhance neovascularization in myocardial ischemia. Myocardial ischemia was induced by placement of an ameroid constrictor around swine left circumflex artery. Four weeks after constrictor placement, CD31+ mononuclear cells (MNCs) were freshly isolated from the peripheral blood of each animal. After overnight incubation of CD31+ MNCs in noncoated plates, nonadhesive cells (NA/CD31+ MNCs) were harvested as the endothelial progenitor cell-enriched fraction. Nonadhesive CD31- cells (NA/CD31- MNCs) were also prepared. Autologous transplantation of 10(7) NA/CD31+ MNCs, 10(7) NA/CD31- MNCs, or PBS was performed with a NOGA mapping injection catheter to target ischemic myocardium. In a parallel study, 10(5) human CD34+ MNCs, 10(5) human CD34- MNCs, or PBS was transplanted into ischemic myocardium of nude rats 10 minutes after ligation of the left anterior descending coronary artery. In the swine study, ischemic area by NOGA mapping, Rentrop grade angiographic collateral development, and echocardiographic left ventricular ejection fraction improved significantly 4 weeks after transplantation of NA/CD31+ MNCs but not after injection of NA/CD31- MNCs or PBS. Capillary density in ischemic myocardium 4 weeks after transplantation was significantly greater in the NA/CD31+ MNC group than the control groups. In the rat study, echocardiographic left ventricular systolic function and capillary density were significantly better preserved in the CD34+ MNC group than in the control groups 4 weeks after myocardial ischemia. These favorable outcomes encourage future clinical trials of catheter-based, intramyocardial transplantation of autologous CD34+ MNCs in the setting of chronic myocardial ischemia.
    Circulation 02/2003; 107(3):461-8. · 15.20 Impact Factor
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    ABSTRACT: This study was designed to test the hypothesis that transcutaneous ultrasound (US) exposure may augment the transfection efficiency and biological outcome associated with nonviral DNA gene transfer. Hindlimb muscles of New Zealand White rabbits were transfected with the reporter plasmid pCMV-beta, with or without US exposure. Optimization studies employed US exposure at various frequencies, mechanical indices, duty cycles, durations of exposure, and exposure time points. Based on these results, we explored the effect of US exposure on nonviral gene transfer of vascular endothelial growth factor (VEGF, phVEGF165) to promote neovascularization of ischemic hindlimbs. Ultrasound at 1 MHz, 100 W/cm(2), 6% duty cycle, and 5 minutes exposure time, applied immediately following DNA injection, was found to be the most effective among the settings tested, increasing beta-galactosidase expression approximately 20 fold. Compared with US exposure alone, or phVEGF165 only, phVEGF165 + US exposure yielded a statistically significant improvement in revascularization, as determined by calf blood pressure ratio, angiographic score, intravascular Doppler blood flow, and capillary/myocyte ratio. These data demonstrate that ultrasound, when applied directly after intramuscular gene transfer, significantly increases transfection efficiency in vivo. The biological significance of this finding was confirmed by augmented limb perfusion in response to US exposure and naked VEGF DNA.
    Molecular Therapy 12/2002; 6(5):576-83. · 7.04 Impact Factor

Publication Stats

11k Citations
845.73 Total Impact Points

Institutions

  • 1992–2009
    • St. Elizabeth's Medical Center
      Boston, Massachusetts, United States
  • 1994–2005
    • Tufts University
      • • Center of Cancer Systems Biology at Caritas St. Elizabeth's Medical Center
      • • Department of Medicine
      Medford, MA, United States
    • McGill University
      Montréal, Quebec, Canada
  • 1999
    • Duke University
      Durham, North Carolina, United States
  • 1995–1997
    • University of California, San Diego
      San Diego, California, United States
  • 1996
    • Harvard Medical School
      Boston, Massachusetts, United States