Angiogenic protein therapy

Therapeutic angiogenesis, in the form of growth factor protein administration or gene therapy, has emerged as a new method of treatment for patients with severe, inoperable coronary artery disease. Improved myocardial perfusion and function after the administration of angiogenic growth factors has been demonstrated in animal models of chronic myocardial ischemia. A recent clinical study reported beneficial long-term effects of therapeutic angiogenesis using FGF-2 protein in terms of freedom from angina and myocardial perfusion on nuclear imaging and suggested that protein angiogenic therapy has the potential to extend treatment options to patients who are not optimal candidates for conventional methods of myocardial revascularization. The ultimate role that angiogenesis will play in the treatment of ischemic heart disease will, however, be determined from adequately powered, randomized, double-blind, placebo-controlled trials. It is likely that endogenous antiangiogenic influences, intrinsic lack of response of patients with severe endothelial dysfunction, and other limitations will have to be overcome before angiogenesis becomes standard therapy for the treatment of coronary artery disease.     

Angiogenesis for the treatment of inoperable coronary disease: the future

Improved treatment options and better management of cardiovascular risk factors have resulted in improved outcomes for patients suffering from severe coronary artery disease. However, coronary artery disease may be of such a diffuse and severe manner that repeated attempts at catheter-based interventions and coronary artery bypass grafting may be unsuccessful at restoring normal myocardial blood flow. It is the goal of therapeutic angiogenesis to restore perfusion to chronically ischemic myocardium using protein growth factors, gene therapy, or, more recently, cell-based therapy, without intervening on the epicardial coronary arteries. However, angiogenesis has not yet provided significant clinical benefit and is still reserved as an experimental treatment for patients who have failed conventional therapies. Once potential endogenous inhibitors of vascular development can be modified, angiogenesis may become more useful for therapeutic purposes. It is hoped that angiogenesis for therapeutic purposes will one day effectively re-create the potent natural processes of vascularization that every human being undergoes during growth and development and become a major modality for the treatment of coronary artery disease.     

Comparison of vascular endothelial growth factor and fibroblast growth factor-2 in a swine model of endothelial dysfunction.

OBJECTIVE: Growth factor based angiogenesis, with or without cell therapy, is a promising therapeutic modality for patients with coronary artery disease. We compared the relative efficacies of surgically delivered vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) in a swine model of hypercholesterolemia-induced endothelial dysfunction which captures many of the pathophysiologic abnormalities of human coronary disease. METHODS: Yucatan mini-swine (20-30 kg), fed a high cholesterol diet (total 20 weeks), underwent circumflex ameroid placement to create chronic myocardial ischemia, followed three weeks later by perivascular administration of VEGF (2 microg; n=6), FGF-2 (100 microg; n=6), or placebo (n=7) in the ischemic territory. Normocholesterolemic animals (n=7) served as controls. Four weeks later, endothelial function, collateral-dependent perfusion, as well as myocardial protein and mRNA levels of angiogenic mediators were assessed. RESULTS: Endothelial dysfunction was observed in all hypercholesterolemic animals as impaired microvessel relaxation in response to adenosine diphosphate and VEGF. VEGF administration improved baseline-adjusted collateral-dependent perfusion at rest (-0.03+/-0.05 vs -0.12+/-0.04, VEGF vs placebo, p=0.09), but FGF-2 delivery caused a significantly greater improvement in perfusion compared to either group (+0.15+/-0.03, p<0.05 vs HC-placebo and HC-VEGF) at rest. Molecular analysis revealed increased eNOS expression (135%+/-8%, p=0.03 vs placebo) in all growth factor treated animals and increased expression of FGF-2 receptor, FGFR1 (65+/-26%, p=0.04 vs placebo), in FGF-2 treated animals. No significant changes were demonstrated in other angiogenic mediators including Akt, Syndecan-4. CONCLUSIONS: In the setting of hypercholesterolemic endothelial dysfunction, FGF-2 is more effective than VEGF at enhancing collateral-dependent perfusion and thus, may be a better candidate than VEGF for angiogenic therapy in patients with end-stage CAD.     

Focal angiogenic therapy for myocardial ischemia

BACKGROUND: Therapeutic angiogenesis, which involves the administration of angiogenic cytokines to stimulate collateral formation and improve myocardial perfusion, is being tested as an alternative treatment for patients with medically intractable angina who are no longer candidates for conventional revascularization techniques. METHODS: Administration of recombinant protein formulations for these growth factors and transfection of the DNA itself have proven effective in animal models. At present, transfection of the DNA (gene therapy) appears preferable in that a single administration achieves a prolonged but transient, localized exposure of the ischemic tissues to the angiogen. The important technical aspects of surgical gene therapy via a mini thoracotomy incision are described. RESULTS: Four Phase I clinical trials of angiogenic therapy recently have been reported, two involving administration of the recombinant protein combined with coronary bypass and two involving gene therapy alone. These studies have shown that this approach is relatively safe; the early evidence of efficacy is encouraging. The largest study reported six-month follow-up on 30 patients who received plasmid DNA for vascular endothelial growth factor-165 (VEGF165) and documented improvement in angina, treadmill exercise tolerance, and myocardial perfusion in the majority of patients studied. CONCLUSIONS: These preliminary results will need to be supported by randomized clinical trials in which angiogenic therapy alone is compared to standard medical therapy or a placebo. Catheter-based intramyocardial gene transfer and combined coronary arterial bypass grafting or transmyocardial laser revascularization plus gene therapy trials are also underway. If proven effective, angiogenic therapy may provide a relatively noninvasive modality for revascularization of ischemic myocardium not amenable to current techniques.     

Angiogenesis — a New Goal in Peripheral Artery Occlusive Disease Therapy

The vasculature is mostly quiescent in the normal adult, with the exception of the growth of new blood vessels during the female reproductive cycle. Recent advances in the knowledge concerning the molecular changes and the identification of genetic events in this vascular quiescence, as well as in vascular growth, has led to an increasing number of studies in which these phenomena are manipulated. Angiogenesis is the growth of new vessels from existing ones. Although new vessel formation is involved in many pathologic situations, like tumour growth, therapeutic angiogenesis has been presented as a novel method for the treatment of ischemic diseases, like peripheral arterial occlusive disease (PAOD).

In experimental studies therapeutic angiogenesis has been produced by recombinant growth-factor protein application as well as by growth factor gene therapy. Most widely studied factors belong to vascular endothelial growth factor (VEGF) or fibroblast growth factor (FGF) families. Studies have also shown that, angiogenic growth factors stimulate endothelial cell migration and accelerate endothelial repair by enhancing post-injury re-endothelization. In clinical studies angiogenic therapy has been evaluated in patients with severe vascular diseases. The results have revealed that therapy is well tolerated as well as safe and that angiogenic therapy has a clear biologic effect. However, controlled studies are still needed to answer the question whether therapeutic angiogenesis offers a real clinical benefit to patients with PAOD.     

Therapeutic angiogenesis in peripheral arterial disease: can biotechnology produce an effective collateral circulation?

The physiological processes of angiogenesis, vasculogenesis and arteriogenesis contribute to the growth of collateral vessels in response to obstructive arterial disease causing lower limb or myocardial ischaemia, but in clinical practice the endogenous angiogenic response is often suboptimal or impaired, e.g. by factors such as ageing, diabetes or drug therapies. Therapeutic angiogenesis is an application of biotechnology to stimulate new vessel formation via local administration of pro-angiogenic growth factors in the form of recombinant protein or gene therapy, or by implantation of endothelial progenitor cells that will synthesize multiple angiogenic cytokines. Numerous experimental and clinical studies have sought to establish 'proof of concept' for therapeutic angiogenesis in PAD and myocardial ischaemia using different treatment modalities, but the results have been inconsistent. This review summarises the mechanisms of angiogenesis and the results of recent trials evaluating the efficacy and safety of different gene therapy, recombinant protein and cellular-based treatment approaches to enhance collateral vessel formation.     

Angiogenesis--a new goal in peripheral artery occlusive disease therapy

The vasculature is mostly quiescent in the normal adult, with the exception of the growth of new blood vessels during the female reproductive cycle. Recent advances in the knowledge concerning the molecular changes and the identification of genetic events in this vascular quiescence, as well as in vascular growth, has led to an increasing number of studies in which these phenomena are manipulated. Angiogenesis is the growth of new vessels from existing ones. Although new vessel formation is involved in many pathologic situations, like tumour growth, therapeutic angiogenesis has been presented as a novel method for the treatment of ischemic diseases, like peripheral arterial occlusive disease (PAOD). In experimental studies therapeutic angiogenesis has been produced by recombinant growth-factor protein application as well as by growth factor gene therapy. Most widely studied factors belong to vascular endothelial growth factor (VEGF) or fibroblast growth factor (FGF) families. Studies have also shown that, angiogenic growth factors stimulate endothelial cell migration and accelerate endothelial repair by enhancing post-injury re-endothelization. In clinical studies angiogenic therapy has been evaluated in patients with severe vascular diseases. The results have revealed that therapy is well tolerated as well as safe and that angiogenic therapy has a clear biologic effect. However, controlled studies are still needed to answer the question whether therapeutic angiogenesis offers a real clinical benefit to patients with PAOD.     

Transmyocardial laser revascularization

It has been almost a decade since transmyocardial laser revascularization (TMR) was approved for clinical use in the United States. The safety of TMR was demonstrated initially with nonrandomized studies in which TMR was used as the only treatment for patients with severe angina. TMR efficacy was proven after multiple randomized controlled trials. These revealed significant angina relief compared to maximum medical therapy in patients with diffuse coronary disease not amenable to conventional revascularization. In light of these results, TMR has been used as an adjunct to coronary artery bypass grafting (CABG). By definition, patients treated with this combined therapy have more severe coronary disease and comorbidities that are associated with end-stage atherosclerosis. Combination CABG + TMR has resulted in symptomatic improvement without additional risk. The likely mechanism whereby TMR has provided benefit is the angiogenesis engendered by the laser-tissue interaction. Improved perfusion and concomitant improvement in myocardial function have been observed post-TMR. Additional therapies to enhance the angiogenic response include combining TMR with stem cell-based treatments, which appear to be promising future endeavors.     

Therapeutic angiogenesis and myocardial regenerative medicine for ischemic heart disease

We have a new therapeutic modality, regenerative medicine, for patients with severe ischemic heart disease. Growth factor administration and cell transplantation are available. Therapeutic angiogenesis with bone marrow cell transplantation has been used clinically with favorable results. Basic fibroblast growth factor slow-release administration has recently started to be used clinically as another angiogenic therapy. It is more potent when combined with a donor artery and omentum (Bio-CABG). Myogenic cell transplantation is in clinical trials aimed at myocardial regeneration. However, it remains unresolved how transplanted myoblasts improve cardiac function and how we can prevent fatal arrhythmia. Many are researching cardiac stem cells and embryonic stem cells as candidates for myocardial regeneration. Recently, the paracrine effects of transplanted mesenchymal stem cells in the ischemic heart have been reported to contribute to improved cardiac function. Therefore, growth factors and cytokines may play an important role in the regeneration process induced by transplanted cells. We combined cell transplanstation with growth factor administration as well as reconstructive surgery for dilated left ventricle, which yielded excellent results. Our integrated strategy may result in the maximal benefits to patients in the future.     

Adenoviral-mediated transfer of vascular endothelial growth factor 121 cDNA enhances myocardial perfusion and exercise performance in the nonischemic state

BACKGROUND: Angiogenic gene therapy has been demonstrated to enhance perfusion to ischemic tissues, but it is unknown whether the administration of angiogenic growth factors will increase blood flow to nonischemic tissues. This study investigates whether enhanced myocardial perfusion can be mediated by adenovirus-mediated transfer of vascular endothelial growth factor 121 cDNA to nonischemic myocardium. METHODS: New Zealand White rabbits received adenovirus (5 x 10(10) particle units) encoding for vascular endothelial growth factor 121 (n = 14) or a control vector without a transgene (n = 13) or saline solution (n = 9) via direct myocardial injection. Fluorescent microsphere perfusion studies and histologic analyses were performed 4 weeks later. In a parallel study, exercise treadmill testing was performed to assess the functional effects of this therapy in Sprague-Dawley rats. RESULTS: Microsphere assessment of myocardial perfusion in rabbits 4 weeks after adenovirus-encoding vascular endothelial growth factor administration was greater than that for rats injected with control vector without a transgene or saline solution (3.2 +/- 0.5 vs 2.7 +/- 0.7 and 2.4 +/- 0.4, respectively; P <.03). The endothelial cell count per high power field was increased in animals injected with adenovirus-encoding vascular endothelial growth factor versus animals injected with control vector without a transgene or saline solution (147 +/- 27 vs 123 +/- 14 and 125 +/- 16 cells, respectively), although this did not reach statistical significance (P =.12). Rats treated with adenovirus-encoding vascular endothelial growth factor also demonstrated prolonged exercise tolerance compared with rats injected with control vector without a transgene or saline solution (exhaustion time: 26 +/- 5 minutes vs 19 +/- 2 minutes and 20 +/- 3 minutes, respectively; P =.006). CONCLUSIONS: Adenovirus encoding-mediated transfer of vascular endothelial growth factor 121 induces an enhancement in regional perfusion in nonischemic myocardium that corresponds to changes in exercise tolerance. Adenovirus-encoding vascular endothelial growth factor therapy may be useful for inducing angiogenesis in the nonischemic state, such as for prophylactic therapy of early coronary artery disease.     

Treatment of inoperable coronary disease and refractory angina: spinal stimulators, epidurals, gene therapy, transmyocardial laser, and counterpulsation

Intractable angina from refractory coronary disease is a severe form of myocardial ischemia for which revascularization provides no prognostic benefit. Inoperable coronary disease is also accompanied by a "vicious cycle" of myocardial dystrophy from a chronic alteration of the cardiac sympathetic tone and sensitization of damaged cardiac tissues. Several adjunctive treatments have demonstrated efficacy when revascularization is either unsuccessful or contraindicated. Spinal cord stimulation modifies the neurologic input and output of the heart by delivering a very low dose of electrical current to the dorsal columns of the high thoracic spinal cord. Neural fibers then release CGRP and other endogenous peptides to the coronary circulation reducing myocardial oxygen demand and enhancing vasodilation of collaterals to improve the myocardial blood flow of the most diseased regions of the heart. Randomized study has shown the survival data at five years is comparable to bypass for high-risk patients. Transmyocardial laser revascularization creates small channels into ischemic myocardium in an effort to enhance flow though studies have shown no improvement in prognosis over medical therapy alone. Enhanced external counterpulsation uses noninvasive pneumatic compression of the legs to improve diastolic filling of the coronary vessels and promote development of collateral flow. The compressor regimen requires thirty-five hours of therapy over a seven-week treatment period. Therapeutic angiogenesis requires injection of cytokines to promote neovascularization and improve myocardial perfusion into the regions affected by chronic ischemia. Phase 3 trials are pending. High thoracic epidural blockade produces a rapid and potent sympatholysis, coronary vasodilation and reduced myocardial oxygen demand in refractory coronary disease. This technique can be used as an adjunct to bypass surgery or medical therapy in chronic or acute unstable angina. Epidurals are easy to perform and often available for outpatient or inpatient use. The rapid anti-ischemic effect may complement therapeutic angiogenesis or other interventions with delayed onset to clinical benefit. A new era for interventional and implant cardiology is beginning to emerge as more clinicians, including cardiologists, gradually learn new procedures to safely provide more therapeutic options for patients suffering refractory angina.     

基因或干细胞移植治疗缺血性冠心病:新世纪的挑战

基因和骨髓干细胞移植是治疗缺血性冠心病的一种新方法。细胞移植的新概念、新的研究方法为未来心血管疾病的治疗和研究提供了令人兴奋的可能性。新近的细胞移植合并基因治疗可能是此领域的革命性进展。实验和初步临床资料证实，基因或者骨髓干细胞移植能产生巨大的生物学效应，使心脏生成新生血管或者心肌细胞，改善心肌血液供应，增加心脏功能或者代谢功能。尽管仍有许多问题需要解决，血管内皮生长因子或者骨髓干细胞移植是安全的，特别适合那些弥漫性血管病变不宜进行外科干预或者PTCA的患者，但仍有必要设计具有机械终点及临床终点的大规模随机、双盲、安慰剂对照试验，进行深入研究。     

Normalization of coronary microvascular reactivity and improvement in myocardial perfusion by surgical vascular endothelial growth factor therapy combined with oral supplementation of l-arginine in a porcine model of endothelial dysfunction

OBJECTIVE: Vascular endothelial growth factor acts in part through nitric oxide release, the availability of which is decreased in endothelial dysfunction associated with advanced coronary artery disease. This could explain the relatively disappointing results of vascular endothelial growth factor therapy in clinical studies compared with animal studies. We examined the influence of L-arginine supplementation to vascular endothelial growth factor therapy on myocardial microvascular reactivity and perfusion in a porcine model of endothelial dysfunction. METHODS: Twenty-four pigs were fed either a normal (NORM, n = 8) or high-cholesterol diet with (CHOL-ARG, n = 8) or without (CHOL, n = 8) L-arginine. All pigs underwent ameroid placement on the circumflex artery and then 3 weeks later received surgical vascular endothelial growth factor treatment. Four weeks after treatment, endothelial-dependent coronary microvascular responses and lateral myocardial perfusion were assessed. Endothelial cell density was determined by means of immunohistochemistry. Vascular endothelial growth factor, endothelial nitric oxide synthase, and Akt levels were determined by means of immunoblotting. RESULTS: Pigs from the CHOL group showed endothelial dysfunction in the circumflex territory, which was normalized by L-arginine supplementation. Vascular endothelial growth factor treatment was ineffective in the CHOL group (circumflex/left anterior descending coronary artery blood flow ratios: 0.95 [rest] and 0.74 [pace] before-after treatment; P < .05 compared with the NORM group). Addition of L-arginine restored the angiogenic effect of vascular endothelial growth factor (ratios: 1.13 [rest] and 1.20 [pace]; P < .05) and was associated with increased endothelial cell density, as well as vascular endothelial growth factor, endothelial nitric oxide synthase, and Akt protein levels in the ischemic territory. CONCLUSIONS: L-Arginine supplementation can restore normal endothelium-dependent vasorelaxation and angiogenic response to vascular endothelial growth factor in a swine model of chronic myocardial ischemia with hypercholesterolemia-induced endothelial dysfunction. These findings suggest a putative role for L-arginine in combination with vascular endothelial growth factor therapy for end-stage coronary artery disease.     

Growth factors for therapeutic angiogenesis in hypercholesterolemic erectile dysfunction

The past decade has seen an explosion of new information on the physiology of penile erection, and pathophysiology of erectile dysfunction （ED）. Hypercholesterolemia is a chronic condition that can lead to degeneration in the vasculature bed and can result in ED if the penile vasculature is involved. Angiogenesis is the growth of new blood vessels from preexisting vasculature. Therapeutic angiogenesis seeks to harness the mechanisms of vascular growth to treat disorders of inadequate tissue perfusion, such as coronary artery disease and ED. There have been tremendous changes in the field of therapeutic angiogenesis over the past decade, and there is much promise for the future. Initial preclinical work with cytokine growth factor delivery resulted in a great deal of enthusiasm for the treatment of ischemic heart and/or peripheral vascular disease, though clinical studies have not achieved similar success. With an increased understanding of the complex mechanisms involved in angiogenesis, novel therapies which target multiple different angiogenic pathways are also being developed and tested. The penis is a convenient tissue target for gene therapy because of its external location and accessibility, the ubiquity of endothelial lined spaces, and low level of blood flow, especially in the flaccid state. Therapeutic angiogenesis is an exciting field that continues to evolve. This review will focus on the development of growth factors for hypercholesterolemic ED, the use of various growth factors for ED therapy, their routes of delivery, and the results in animal studies.     

Gene-based therapeutic angiogenesis

Stimulating new blood vessel growth in ischemic hearts or limbs is a hopeful new approach for patients with advanced vascular disease. This approach is based generally upon the hypothesis that sufficient exposure of a vascular bed to an angiogenic protein will stimulate neovascularization. Most angiogenic proteins have a markedly short serum half-life. To overcome this, researchers have turned to gene therapy to ensure continuous expression of angiogenic proteins and prolonged exposure in the targeted vascular beds. This field is still evolving, and although early clinical trial results suggest angiogenic gene therapy can be successful, many questions remain. As we continue to learn more about the complex interplay and coordinated action of the various factors involved in regulating angiogenesis, it is likely that strategies for therapeutic angiogenesis will continue to change. This review addresses the current state of angiogenic gene therapy, contrasts gene therapy with angiogenic protein delivery, describes early and recent clinical trial data, and discusses potential new directions in the field.     

Effects of basic fibroblast growth factor microspheres on angiogenesis in ischemic myocardium and cardiac function: analysis with dobutamine cardiovascular magnetic resonance tagging.

OBJECTIVE: Therapeutic angiogenesis with angiogenic growth factors has described as one of the promising methods for collateral formation in the treatment of ischemic heart diseases. The purpose of this study is to assess the value of intramyocardial injection of slow-released basic fibroblast growth factor microspheres on angiogenesis and cardiac function in the early period of acute infarcted myocardium with dobutamine cardiovascular magnetic resonance tagging. METHODS: Acute myocardial infarction was made by ligation of the left anterior descending coronary artery distal to its first diagonal branch. Immediately after coronary artery occlusion, 1 ml of saline containing 100 microg of basic fibroblast growth factor microspheres was injected into peri-infarct myocardial area in the basic fibroblast growth factor group, whereas only gelatin hydrogel microspheres with 1 ml of saline was given in control dogs. Cardiac function was evaluated by cine magnetic resonance imaging. Dobutamine cardiovascular magnetic resonance was performed at rest and during low doses of dobutamine to assess regional wall motion. Immunohistochemical study with von Willebrand factor was performed to observe angiogenesis. RESULTS: Left ventricular ejection fraction improved markedly 10 and 17 days after treatment in the basic fibroblast growth factor group. The basic fibroblast growth factor group had more viable myocardium. Microvessel density was higher in the basic fibroblast growth factor group than in the control group except the first day after treatment. CONCLUSIONS: Intramyocardial administration of basic fibroblast growth factor microspheres can promote the growth of microvessels and improve left ventricular function and myocardial viability in the early period of acute myocardial infarction.     

Inhibition of the cardiac angiogenic response to exogenous vascular endothelial growth factor

BACKGROUND: The angiogenic effects of vascular endothelial growth factor (VEGF) are mediated by the stimulation of endothelial nitric oxide synthase (eNOS) and nitric oxide release. Nitric oxide availability is decreased in patients with coronary disease, a possible explanation for the humble results of VEGF in clinical trials. We sought to examine the effects of exogenous VEGF in a model of endothelial dysfunction. METHODS: Miniswine fed either a regular (N = 6, group NORM) or hypercholesterolemic diet (N = 6, HICHOL) underwent ameroid placement on the circumflex artery. Three weeks later, baseline myocardial perfusion was assessed by microsphere injections, and all pigs were treated with VEGF. Four weeks later, microsphere injections were repeated and the hearts harvested. Endothelial-dependent coronary microvascular reactivity, and VEGF and eNOS expression were assessed. RESULTS: HICHOL pigs showed significant endothelial dysfunction in the ischemic territory. Post-treatment myocardial blood flow in the circumflex territory was significantly higher in the NORM compared to the HICHOL group. VEGF and eNOS levels were increased in the ischemic territory in the NORM group but decreased in the HICHOL group. CONCLUSIONS: The cardiac angiogenic response to VEGF was markedly inhibited in a hypercholesterolemia-induced porcine model of endothelial dysfunction. Coronary endothelial dysfunction could be an obstacle to the efficacy of clinical angiogenesis protocols and a putative therapeutic target.     

Therapeutic Angiogenesis Induced by Injecting Hepatocyte Growth Factor in Ischemic Canine Hearts

Purpose Therapeutic angiogenesis, induced by the direct injection of angiogenic growth factors or by transmyocardial laser revascularization (TMLR), has shown great potential as a new therapeutic strategy for end-stage coronary artery disease. However, no significant differences in angiogenic effects of TMLR and vascular endothelial growth factor (VEGF) have been reported. We compared the effects of the intramyocardial injection of hepatocyte growth factor (HGF), a novel angiogenic factor, with those of TMLR, by evaluating the improvement in regional blood flow and regional function in a canine heart model of chronic ischemia.Methods To create a model of chronic ischemia, we ligated the left anterior descending artery (LAD) in 15 beagles. We divided the dogs into three groups according to the treatment given 1 month after ligation. Four dogs were given an intracardial injection of human recombinant HGF (H group), six dogs were given TMLR (T group), and five dogs were used as a control (C group). We compared the degree of improvement in regional blood flow and regional function 1 month after the treatment.Results The regional myocardial blood flow and function were significantly better in the H group than in the T or C groups (P < 0.05). Histologically, there were significantly more von Willebrand factor-positive cells in the LAD region in the H group than in the T or C groups.Conclusion The intramural injection of recombinant human HGF resulted in therapeutic angiogenesis with an intrinsic contractile state, and it may have greater advantages than TMLR for the treatment of chronic ischemic heart disease.     

Effects of L-arginine on the endogenous angiogenic response in a model of hypercholesterolemia

BACKGROUND: The angiogenic properties of vascular endothelial growth factor and fibroblast growth factor-2 are mediated in part through nitric oxide release, whose availability is decreased in endothelial dysfunction associated with advanced coronary artery disease. We examined the influence of L-arginine supplementation on the endogenous angiogenic response to ischemia in a porcine model of hypercholesterolemia. METHODS: Eighteen Yucatan pigs were fed either a normal (NORM, n=6) or a high-cholesterol diet, with (CHOL-ARG, n=6) or without (CHOL, n=6) L-arginine (100 mg/kg/day), throughout the experiment. All pigs underwent ameroid constrictor placement on the circumflex artery (LCx). Seven weeks later, endothelium-dependent coronary microvascular responses to fibroblast growth factor-2 and vascular endothelial growth factor were assessed by videomicroscopy. Perfusion was assessed with radioactive microspheres; angiogenesis was evaluated by platelet-endothelial cell adhesion molecule-1 (CD-31) staining. Regional myocardial function was assessed by sonomicrometry. Expression of endothelial nitric oxide synthase and inducible nitric oxide synthase was measured by Western blot analyses. RESULTS: Pigs from the CHOL group showed significant endothelial dysfunction in the LCx territory. The dysfunction was normalized partially by L-arginine supplementation, which restored the response in the LCx territory to the level of the nonischemic anterior wall. L-arginine supplementation resulted in increases of perfusion, density of capillary endothelial, and level of endothelial nitric oxide synthase in the ischemic region. Despite these findings, no improvement in myocardial regional function was found. CONCLUSIONS: L-arginine supplementation can partially restore endothelium-dependent vasorelaxation and improve myocardial perfusion in a swine model of chronic myocardial ischemia with hypercholesterolemia-induced endothelial dysfunction. These findings suggest a putative role for L-arginine in combination with growth factor therapy for end-stage coronary artery disease.