Proangiogenic Gene Therapy Research Articles

BMP2 gene transfer induces pericardial effusion and inflammatory response in the ischemic porcine myocardium.

Pro-angiogenic gene therapy is being developed to treat coronary artery disease (CAD). We recently showed that bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor-A synergistically regulate endothelial cell sprouting in vitro. BMP2 was also shown to induce endocardial angiogenesis in neonatal mice post-myocardial infarction. In this study, we investigated the potential of BMP2 gene transfer to improve cardiomyocyte function and neovessel formation in a pig chronic myocardial infarction model. Ischemia was induced in domestic pigs by placing a bottleneck stent in the proximal part of the left anterior descending artery 14 days before gene transfer. Intramyocardial gene transfers with adenovirus vectors (1 × 1012 viral particles/pig) containing either human BMP2 (AdBMP2) or beta-galactosidase (AdLacZ) control gene were performed using a needle injection catheter. BMP2 transgene expression in the myocardium was detected with immunofluorescence staining in the gene transfer area 6 days after AdBMP2 administration. BMP2 gene transfer did not induce angiogenesis or cardiomyocyte proliferation in the ischemic pig myocardium as determined by the quantitations of CD31 or Ki-67 stainings, respectively. Accordingly, no changes in heart contractility were detected in left ventricular ejection fraction and strain measurements. However, BMP2 gene transfer induced pericardial effusion (AdBMP2: 9.41 ± 3.17 mm; AdLacZ: 3.07 ± 1.33 mm) that was measured by echocardiography. Furthermore, an increase in the number of immune cells and CD3+ T cells was found in the BMP2 gene transfer area. No changes were detected in the clinical chemistry analysis of pig serum or histology of the major organs, implicating that the gene transfer did not induce general toxicity, myocardial injury, or off-target effects. Finally, the levels of fibrosis and cardiomyocyte apoptosis detected by Sirius red or caspase 3 stainings, respectively, remained unaltered between the groups. Our results demonstrate that BMP2 gene transfer causes inflammatory changes and pericardial effusion in the adult ischemic myocardium, which thus does not support its therapeutic use in chronic CAD.

Therapeutic Neovascularization for Refractory Angina-Are We Any Closer?

Therapeutic Neovascularization for Refractory Angina-Are We Any Closer?

A “controlled CO release” and “pro-angiogenic gene” dually engineered stimulus-responsive nanoplatform for collaborative ischemia therapy

Ischemic injury is mostly caused by insufficient blood supply, excessive inflammation and increased oxidative stress. Pro-angiogenic gene delivery can foster vascular remodeling and increase blood perfusion, but the adverse ischemia microenvironment leads to inadequate therapy effect and high recurrence rate. A novel combination strategy should be developed for the effective therapy of ischemic injury via remediating microenvironment and accelerating revascularization simultaneously. Carbon monoxide (CO) exhibits multiple bio-functions, especially anti-inflammation and anti-oxidant effects, suggesting that it might be an attractive candidate for ischemia therapy. Herein, for the first time, “controlled CO release” was introduced to treat limb ischemia. We developed the controlled CO delivery nanoplatform (PR@CORM) via encapsulating CO-releasing molecule-401 by the stimulus-responsive and ECs-adhesive peptide functionalized nanocarrier. In response to oxidants, PR@CORM can intelligently release therapeutic CO gas to remediate the microenvironment, but the pro-angiogenic effect is still disappointing. We thereby combined “CO therapy” and “pro-angiogenic gene therapy” to achieve the cooperative effects for ischemia therapy. This strategy exhibits superiority in the treatment of ischemic injury through extensively normalizing the microenvironment and accelerating revascularization. The “controlled CO release” serves as a scavenger of inflammation and reactive oxygen species, and pro-angiogenic gene holds potential for ischemia therapy.

Progress of Gene Therapy in Cardiovascular Disease.

Gene therapy has been extensively studied in peripheral and cardiac ischemia, heart and vein graft failure, and dyslipidemia, but most clinical trials failed to show their efficacies despite good outcomes in preclinical studies. So far, 2 gene therapies for dyslipidemia and one for critical limb ischemia in peripheral artery disease have been approved. In critical limb ischemia, gene therapy using proangiogenic factors has emerged as a novel therapeutic modality for promoting angiogenesis. Initial researches mainly focused on vascular endothelial growth factor, fibroblast growth factor, or hepatocyte growth factor. After the favorable results of basic research, several phase I and II clinical trials of these proangiogenic factors have shown promising results. However, only a phase III clinical trial of the intramuscular injection of hepatocyte growth factor plasmid DNA has shown successful outcomes, and it was recently approved in Japan for treating patients with critical limb ischemia who have ulcers and for whom no alternative therapeutic options are available. DNA vaccine is another promising modality of gene therapy. An antitumor vaccine suppressing angiogenesis through the inhibition of proangiogenic factors and an antihypertensive vaccine inhibiting the renin-angiotensin system are representative DNA vaccines. The advantage of DNA vaccine is its long-term effectiveness with a few vaccinations; however, the benefits and risks, such as adverse T-cell reaction against self-antigen or long-term side effects, of DNA vaccines should be carefully evaluated. In this review, we discuss the recent advances in proangiogenic gene therapy for critical limb ischemia and DNA vaccine for hypertension.

Abstract 11987: Adenoviral Intramyocardial VEGF-D Gene Transfer Increases Myocardial Perfusion in Refractory Angina Patients

Background: There is a rapidly growing number of refractory angina patients who in spite of the optimal medical therapy are severely symptomatic and who are not suitable for revascularization. Proangiogenic gene therapy is a potential new treatment for these patients. We evaluated for the first time safety, feasibility and efficacy of adenoviral (Ad) gene therapy using a new member of the VEGF family, VEGF-D, in the treatment of refractory angina. Methods and Results: KAT301 trial is a randomized, placebo-controlled, single-blinded phase I/II study. A total of 30 patients were randomized to intramyocardial AdVEGF-D gene transfer (VEGF group) or placebo (control group) with a 4:1 ratio. VEGF group underwent transseptal puncture and electroanatomical mapping of left ventricle with NOGA system (Cordis Corp), followed by intramyocardial injection of AdVEFG-D in the ischemic areas. The control group underwent transseptal puncture, left ventricle mapping and intracardiac saline infusion. Vital signs and laboratory assessments were measured at baseline and at 1, 2, 7,14 days and 3 months after the gene therapy to evaluate the safety and feasibility. Twenty patients underwent assessment of myocardial perfusion and blood flow reserve at rest and during adenosine induced exercise with positron emission tomography (15O-PET) at baseline and three months after the procedure. Mild transient elevation in body temperature and CRP and moderate hypotension was detected in VEGF group after the procedure. Troponine-T was elevated in both groups after the procedure but was normalized in two days. Perfusion reserve at 3 months in the myocardial segment with the lowest perfusion reserve at baseline increased significantly in the VEGF group (0.93±0.30 to 1.21±0.39, p=0.035) but not in the controls (1.21±0.63 to 1.53±0.67, p=0.343). No antibody responses were found against the transgene in the VEGF group after the treatment. Conclusion: Intramyocardial AdVEGF-D gene therapy is well tolerated in refractory angina patients. Changes in PET analysis at 3 months indicate that gene therapy can enhance myocardial perfusion in segments with the lowest perfusion reserve. Based on the results a randomized, controlled, blinded phase II/III trial is justified.

Ultrasound-mediated gene delivery – Cardiovascular applications for Chronic ischemia, heart failure, and ischemia-reperfusion injury

Ultrasound-mediated gene delivery (UMGD) is a non-invasive gene transfer technique, utilizing high power ultrasound and DNA-bearing microbubbles. Despite modest transfection efficiency, its high organ, tissue specificity, and repeatability make it an attractive therapeutic option. UMGD has been used in a variety of in vivo applications, including cardiac and skeletal muscle, kidney, liver, cerebral, and even lung, and have been studied using many gene vectors, including plasmid, viral, and small interfering RNA. This presentation will focus specifically on cardiac applications using plasmid DNA, including (1) introduction of UMGD in the heart, including optimization of parameters and protocols, (2) UMGD for therapeutic angiogenesis in chronic ischemia, including multi pro-angiogenic gene therapy and combination gene- and progenitor cell-based therapies for chronic hindlimb ischemia, and (3) applications for anti-apoptotic therapy in heart failure and ischemia-reperfusion injury.

Circulation: Clinical Summaries

<i>Circulation:</i> Clinical Summaries

Long-term VEGF-A expression promotes aberrant angiogenesis and fibrosis in skeletal muscle

Vascular endothelial growth factor A (VEGF-A) induces strong angiogenesis and it has been widely used in proangiogenic gene therapy studies. However, little is known about long-term effects of VEGF-A expression in skeletal muscle. Here the long- term effects of adeno-associated virus (AAV) encoding human VEGF-A(165) (AAV-VEGF-A) gene transfer in normal and ischemic rabbit hindlimb skeletal muscles were studied. AAV-LacZ was used as a control. In one-year follow-up, a remarkable increase in skeletal muscle perfusion compared with AAV-LacZ was observed measured with Doppler and contrast pulse sequence ultrasound. Angiogenesis was also seen in histology as enlarged and sprouting capillaries. In addition to favorable angiogenic effects, aberrant vascular structures with CD31 positive cell layers were seen inside muscle fibers after AAV-VEGF-A gene transfer. Importantly, we found increased amounts of extracellular matrix with a high number of macrophages and fibrosis in AAV-VEGF-A transduced muscles. No changes in skeletal muscle morphology were detected in AAV-LacZ transduced muscles. Our results indicate that local AAV-VEGF-A gene transfer efficiently promotes long-term angiogenesis in large animal model. However, non-regulated expression of VEGF-A causes unfavorable changes in muscle morphology, which suggests the need for regulation of the transgene expression in long-term AAV-mediated VEGF-A gene transfer applications.

New aspects in vascular gene therapy

Advances in clinical gene therapy have been modest although significant progress has been made during the past few years. New viruses have been introduced and new results have been collected from preclinical and clinical studies. This review will focus on cardiovascular and especially proangiogenic gene therapy. Recent results from preclinical developments and clinical trials will be discussed.

Coadministration of Adenoviral Vascular Endothelial Growth Factor and Angiopoietin-1 Enhances Vascularization and Reduces Ventricular Remodeling in the Infarcted Myocardium of Type 1 Diabetic Rats

OBJECTIVEHyperglycemia impairs angiogenesis in response to ischemia, leading to ventricular remodeling. Although the effects of overexpressing angiogenic growth factors have been studied in inducing angiogenesis, the formation of functional vessels remains a challenge. The present study evaluates the reversal of diabetes-mediated impairment of angiogenesis in the infarcted diabetic rat myocardium by proangiogenic gene therapy.RESEARCH DESIGN AND METHODSAd.VEGF and Ad.Ang1 were intramyocardially administered in combination immediately after myocardial infarction to nondiabetic and diabetic rats. Ad.LacZ was similarly administered to the respective control groups. The hearts were excised for molecular and immunohistochemical analysis at predetermined time points. The myocardial function was measured by echocardiography 30 days after the intervention.RESULTSWe observed reduced fibrosis and increased capillary/arteriolar density along with reduced ventricular remodeling, as assessed by echocardiography in the treated diabetic animals compared with the nontreated diabetic controls. We also observed increased phosphorylated mitogen-activated protein kinase–activated protein kinase-2, 2 days after the treatment and increased expression of vascular endothelial growth factor (VEGF), Flk-1, angiopoietin-1 (Ang-1), Tie-2, and survivin, 4 days after treatment in the diabetic animals. Gel shift analysis revealed that the combination gene therapy stimulated the DNA binding activity of nuclear factor-κB in the diabetic animals.CONCLUSIONSOur preclinical data demonstrate the efficacy of coadministration of adenoviral VEGF and Ang-1 in increasing angiogenesis and reducing ventricular remodeling in the infarcted diabetic myocardium. These unique results call for the initiation of a clinical trial to assess the efficacy of this therapeutic strategy in the treatment of diabetes-related human heart failure.

VEGF Gene Therapy Fails to Improve Perfusion of Ischemic Myocardium in Patients With Advanced Coronary Disease: Results of the NORTHERN Trial

Despite the promise of proangiogenic gene therapy most clinical trials have failed to show benefit for the primary end point analysis. The NOGA angiogenesis Revascularization Therapy: assessment by RadioNuclide imaging (NORTHERN) trial was a double-blind, placebo-controlled study of intramyocardial vascular endothelial growth factor (VEGF165) gene therapy versus placebo, involving seven sites across Canada, designed to overcome major limitations of previous proangiogenic gene therapy trials. A total of 93 patients with refractory Canadian Cardiovascular Society (CCS) class 3 or 4 anginal symptoms were randomized to receive 2,000 microg of VEGF plasmid DNA or placebo (buffered saline) delivered via the endocardial route using an electroanatomical NOGA guidance catheter. There was no difference between the VEGF-treated and the placebo groups in the primary end point of change in myocardial perfusion from baseline to 3 or 6 months, assessed by single photon emission tomography (SPECT) imaging, although a significant reduction in the ischemic area was seen in both groups. Also, similar improvements in exercise treadmill time and anginal symptoms were seen in the VEGF and the placebo groups at 3 and 6 months, although again there were no differences between these groups. Despite the intramyocardial administration of a high "dose" of plasmid DNA using a percutaneous guidance catheter system, there was no benefit of VEGF gene therapy at 3 or 6 months for any of the end points studied.

Endothelial-targeted Gene Transfer of Hypoxia-inducible Factor-1α Augments Ischemic Neovascularization Following Systemic Administration

Hypoxia-inducible factor-1α (HIF-1α) is a key regulator of the response to low oxygen levels and has been used for therapeutic angiogenesis. Various routes of administration have been used for delivering genes to the ischemic region including the intramuscular (IM) and intraarterial routes. When compared with these delivery methods, the intravenous (IV) route confers many advantages, including less invasiveness and lower cost. However, its use is hampered by the fact that it does not result in specific and robust tissue expression of the genes. Our aim was to determine the feasibility, safety, and therapeutic efficacy of systemic administration of adenoviral-mediated HIF-1α targeted to the endothelium. Using confocal microscopy and biodistribution studies we demonstrated that a modified murine preproendothelin-1 promoter (PPE1-3x) can target gene expression specifically to endothelial cells within ischemic muscle following systemic IV administration in C57BL/6 mice. Accordingly, an adenovirus expressing a PPE1-3x-regulated stabilized HIF-1α molecule, further activated by constitutive activation of its C-transactivation domain (C-TAD), was created. Systemic tail-vein administration of this adenovirus in a mouse hindlimb ischemia model resulted in enhanced blood perfusion, improved clinical outcome, and increased capillary density without systemic toxicity, in contrast to the profound systemic side effects and lack of therapeutic efficacy following cytomegalovirus (CMV)-regulated HIF-1α administration. Collectively, these data suggest that transcriptionally controlled systemic proangiogenic gene therapy is feasible, safe, and efficacious.

Therapeutic angiogenesis with placental growth factor improves exercise tolerance of ischaemic rabbit hindlimbs

We investigated the effects of angiogenic gene therapy with adenoviral placental growth factor(131) (AdPlGF) on aerobic capacity and exercise tolerance in a rabbit hindlimb ischaemia model. We also assessed whether strong angiogenic changes such as capillary arterialization and formation of artery-venous shunts compromise oxygen transport to target tissues resulting in suboptimal therapeutic efficacy. Hindlimb ischaemia was surgically induced in New Zealand White rabbits (n = 20) that a day later received intramuscular (i.m.) AdPlGF or AdLacZ (3 x 10(11)vp) gene transfer (GT). Corresponding GTs were also done in healthy non-ischaemic rabbits (n = 10). Muscle energy metabolism and skeletal muscle perfusion were studied non-invasively before GT and at 6 and 28 days using (31)P-magnetic resonance spectroscopy and contrast pulse sequence ultrasound, respectively. Oedema was quantified using modified Miles assay at sacrifice. AdPlGF increased perfusion 7.8-fold and improved aerobic capacity of ischaemic limbs 45% compared with AdLacZ controls (P < 0.05) at 6 days. In non-ischaemic limbs, strong angiogenic response to GT, including capillary arterialization and acute oedema, did not impair muscle energy metabolism. This study shows that proangiogenic gene therapy can significantly improve performance of ischaemic limbs and supports the concept of therapeutic angiogenesis for the treatment of patients with ischaemia.

Stabilized HIF‐1α is superior to VEGF for angiogenesis in skeletal muscle via adeno‐associated virus gene transfer

Therapeutic angiogenesis provides a potential alternative for the treatment of cardiovascular ischemic diseases. Vascular endothelial growth factor (VEGF) is an important component of the angiogenic response to ischemia. Here we used adeno-associated virus (AAV) gene delivery to skeletal muscle to examine the effects of VEGF vs. a stabilized form of hypoxia-inducible factor-1alpha (HIF-1alpha). The recombinant AAVs were injected into mouse tibialis anterior muscle, and their effects were analyzed by immunohistochemistry and functional assays. These analyses showed that stabilized HIF-1alpha markedly increase capillary sprouting and proliferation, whereas VEGF164 or VEGF120 induced only proliferation of endothelial cells without formation of proper capillary structures. The Evans Blue permeability assay indicated that, unlike VEGF, HIF-1alpha overexpression did not increase vascular leakiness in the transduced muscle. Doppler ultrasound imaging showed that vascular perfusion in the HIF-1alpha treated muscles was significantly enhanced when compared to the controls and not further improved by co-expression of the arteriogenic growth factors angiopoietin-1 or platelet-derived growth factor-B. Our results show that AAV-mediated transduction of a stabilized form of HIF-1alpha can circumvent the problems associated with overexpression of individual angiogenic growth factors. HIF-1alpha should thus offer a potent alternative for pro-angiogenic gene therapy.