Elevated circulating levels of basic fibroblast growth factor and vascular endothelial growth factor in patients with acute myocardial infarction

Changes in serum basic fibroblast growth factor concentration following intracordal injection

Objective

Although many studies have reported improvements in voice outcomes with intracordal trafermin injection, there is a lack of data documenting its changes in serum basic fibroblast growth factor (bFGF) blood concentration. This study examined whether serum bFGF concentrations change after intracordal trafermin injection.

Methods

This retrospective study was conducted at Tokyo Voice Center. We investigated serum bFGF concentrations before and after injection in 40 patients who underwent intracordal trafermin injection. There were 26 males and 14 females, with an age ranging from 13 to 88 years (average 53.25 years). They were diagnosed with paralysis (15 patients), atrophy (15 patients), sulcus (8 patients), and others (2 patients: scar and functional), presenting with severe hoarseness that interfered with daily life.

Results

The mean pre- and post-injective serum bFGF concentration of the 40 patients was 6.689 and 4.658 pg/mL, respectively. The difference in mean serum bFGF concentration between pre- and post-injective was -2.031 pg/mL. The Pearson correlation coefficient was calculated to evaluate the correlation between dosage of trafermin and post-injective serum bFGF concentration, and a moderate correlation was found at r = 0.52. Generalized linear model regression analysis was performed for the purpose of adjusting for confounding among variables. The only variable that showed a statistically predominant association with post-injective serum bFGF concentrations was the dosage of trafermin, with an estimated regression coefficient of 0.048.

Conclusion

In this study, the dosage of trafermin we injected and post-injective serum bFGF concentrations were dose-dependent but the amount of changes in the serum bFGF concentration was negligible within the physiological range. Therefore, as with subcutaneous and wound administration, intracordal trafermin injections may be safe.

Level of Evidence

Level IV.

Circulating Proangiogenic Cells and Proteins in Patients with Glioma and Acute Myocardial Infarction: Differences in Neovascularization between Neoplasia and Tissue Regeneration

Although extensive angiogenesis takes place in glial tumors, antiangiogenic therapies have remained without the expected success. In the peripheral circulation of glioma patients, increased numbers of endothelial precursor cells (EPCs) are present, potentially offering targets for antiangiogenic therapy. However, for an antiangiogenic therapy to be successful, the therapy should specifically target glioma-related EPC subsets and secreted factors only. Here, we compared the EPC subsets and plasma factors in the peripheral circulation of patients with gliomas to acute myocardial infarctions. We investigated the five most important EPC subsets and 21 angiogenesis-related plasma factors in peripheral blood samples of 29 patients with glioma, 14 patients with myocardial infarction, and 20 healthy people as controls, by FACS and Luminex assay. In GBM patients, all EPC subsets were elevated as compared to healthy subjects. In addition, HPC and KDR⁺ cell fractions were higher than in MI, while CD133⁺ and KDR⁺CD133⁺ cell fractions were lower. There were differences in relative EPC fractions between the groups: KDR⁺ cells were the largest fraction in GBM, while CD133⁺ cells were the largest fraction in MI. An increase in glioma malignancy grade coincided with an increase in the KDR⁺ fraction, while the CD133⁺ cell fraction decreased relatively. Most plasma angiogenic factors were higher in GBM than in MI patients. In both MI and GBM, the ratio of CD133⁺ HPCs correlated significantly with elevated levels of MMP9. In the GBM patients, MMP9 correlated strongly with levels of all HPCs. In conclusion, the data demonstrate that EPC traffic in patients with glioma, representing neoplasia, is different from that in myocardial infarction, representing tissue regeneration. Glioma patients may benefit from therapies aimed at lowering KDR⁺ cells and HPCs.

Association between the ratio of anti-angiogenic isoform of VEGF-A to total VEGF-A and adverse clinical outcomes in patients after acute myocardial infarction

Background

Vascular endothelial growth factor-A (VEGF-A) promotes neovascularization and is attracting considerable attention as a remarkable risk factor in patients after acute myocardial infarction (AMI). In contrast, the association between VEGF-A₁₆₅b, which is the main anti-angiogenic isoform of VEGF-A, and adverse clinical outcomes after AMI remains unclear. The present study aimed to investigate the association between serum VEGF-A₁₆₅b and major adverse cardiac and cerebrovascular events (MACCEs) after percutaneous coronary intervention (PCI) for AMI.

Methods

We evaluated 23 patients with AMI who underwent primary percutaneous coronary intervention. VEGF-A and VEGF-A₁₆₅b levels were measured on admission (day 1) and at days 3, 7, and 30 after PCI.

Results

The levels of total VEGF-A tended to be lower, while the ratio of VEGF-A₁₆₅b to total VEGF-A tended to be higher in patients with MACCEs than in those without. The patients with a high ratio of VEGF-A₁₆₅b to total VEGF-A had a significantly higher risk of MACCEs using the cut-off values for MACCEs at day 30 after PCI (0.87 vs. 0.25, log-rank test, p = 0.0058).

Conclusion

The assessment of VEGF-A₁₆₅b combined with VEGF-A may be a valuable screening tool for predicting MACCEs in clinical practice.

Balance between angiogenic and anti-angiogenic isoforms of VEGF-A is associated with the complexity and severity of coronary artery disease

INTRODUCTION

Assessing the complexity of coronary artery disease (CAD) is clinically important. Vascular endothelial growth factor A (VEGF-A) is a powerful and the most important regulator of angiogenesis. It has been reported that the anti-angiogenic isoform of VEGF-A (VEGF-A₁₆₅b) inhibits angiogenesis. The purpose of this study was to evaluate the relationship between the complexities of CAD using the Syntax score (SS) and the levels of circulating total VEGF-A or VEGF-A₁₆₅b.

METHODS

A total of 268 patients who underwent percutaneous coronary intervention (PCI) were enrolled. Of these, 73 patients without acute coronary syndrome or previous revascularization were included in this study. These subjects were divided into two groups according to the SS. Circulating total VEGF-A and VEGF-A₁₆₅b levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Circulating levels of total VEGF-A were significantly higher in the SS>22 (high SS) group than in the SS≤22 (low SS) group (p=0.018). Moreover, the ratio of VEGF-A₁₆₅b to total VEGF-A was significantly lower for the high SS group (p=0.004). The levels of total VEGF-A independently predicted high SS after adjusting for other significant variables among patients who underwent PCI (odds ratio, 1.004; 95% CI, 1.001 to 1.006; p=0.01).

CONCLUSIONS

These data indicated that high SS was associated with circulating levels of total VEGF-A and the ratio of VEGF-A₁₆₅b to total VEGF-A in patients with complex CAD.

Intramyocardial delivery of VEGF165 via a novel biodegradable hydrogel induces angiogenesis and improves cardiac function after rat myocardial infarction

Vascular endothelial growth factor (VEGF), an independent mitogen, has been reported to induce angiogenesis and thus attenuates the damage induced by myocardial infarction (MI). VEGF165 is the most abundant and predominant isoform of VEGF. This study investigates whether this effect could be strengthened by local intramyocardial injection of VEGF165 along with a novel biodegradable Dex-PCL-HEMA/PNIPAAm hydrogel and ascertains its possible mechanism of action. Rat models of myocardial infarction were induced by coronary artery ligation. Phosphate-buffered saline (PBS group), Dex-PCL-HEMA/PNIPAAm hydrogel (Gel group), phosphate-buffered saline containing VEGF165 (VP group), and hydrogel containing VEGF165 (VPG group) were injected into a peri-infarcted area of cardiac tissue immediately after myocardial infarction, respectively. The sham group was thoracic but without myocardial infarction. The injection of VEGF165 along with a hydrogel induced angiogenesis, reduced collagen content and MI area, inhibited cell apoptosis, increased the level of VEGF165 protein and the expression of flk-1 and flt-1, and improved cardiac function compared with the injection of either alone after MI in rats. The results suggest that injection of VEGF165 along with a hydrogel acquires more cardioprotective effects than either alone in rat with MI by sustained release of VEGF165, then may enhance the feedback between VEGF and its receptors flk-1 and flt-1.

In vitro endothelial cell proliferation assay reveals distinct levels of proangiogenic cytokines characterizing sera of healthy subjects and of patients with heart failure

Although myocardial angiogenesis is thought to play an important role in heart failure (HF), the involvement of circulating proinflammatory and proangiogenic cytokines in the pathogenesis and/or prognosis of HF has not been deeply investigated. By using a highly standardized proliferation assay with human endothelial cells, we first demonstrated that sera from older (mean age 52 ± 7.6 years; n = 46) healthy donors promoted endothelial cell proliferation to a significantly higher extent compared to sera obtained from younger healthy donors (mean age 29 ± 8.6 years; n = 20). The promotion of endothelial cell proliferation was accompanied by high serum levels of several proangiogenic cytokines. When we assessed endothelial cell proliferation in response to HF patients' sera, we observed that a subset of sera (n = 11) promoted cell proliferation to a significantly lesser extent compared to the majority of sera (n = 18). Also, in this case, the difference between the patient groups in the ability to induce endothelial cell proliferation correlated to significant (P < 0.05) differences in serum proangiogenic cytokine levels. Unexpectedly, HF patients associated to the highest endothelial proliferation index showed the worst prognosis as evaluated in terms of subsequent cardiovascular events in the follow-up, suggesting that high levels of circulating proangiogenic cytokines might be related to a worse prognosis.

Increase in parasympathetic tone by pyridostigmine prevents ventricular dysfunction during the onset of heart failure

Heart failure (HF) is characterized by elevated sympathetic activity and reduced parasympathetic control of the heart. Experimental evidence suggests that the increase in parasympathetic function can be a therapeutic alternative to slow HF evolution. The parasympathetic neurotransmission can be improved by acetylcholinesterase inhibition. We investigated the long-term (4 wk) effects of the acetylcholinesterase inhibitor pyridostigmine on sympathovagal balance, cardiac remodeling, and cardiac function in the onset of HF following myocardial infarction. Myocardial infarction was elicited in adult male Wistar rats. After 4 wk of pyridostigmine administration, per os, methylatropine and propranolol were used to evaluate the cardiac sympathovagal balance. The tachycardic response caused by methylatropine was considered to be the vagal tone, whereas the bradycardic response caused by propranolol was considered to be the sympathetic tone. In conscious HF rats, pyridostigmine reduced the basal heart rate, increased vagal, and reduced sympathetic control of heart rate. Pyridostigmine reduced the myocyte diameter and collagen density of the surviving left ventricle. Pyridostigmine also increased vascular endothelial growth factor protein in the left ventricle, suggesting myocardial angiogenesis. Cardiac function was assessed by means of the pressure-volume conductance catheter system. HF rats treated with pyridostigmine exhibited a higher stroke volume, ejection fraction, cardiac output, and contractility of the left ventricle. It was demonstrated that the long-term administration of pyridostigmine started right after coronary artery ligation augmented cardiac vagal and reduced sympathetic tone, attenuating cardiac remodeling and left ventricular dysfunction during the progression of HF in rats.

Low molecular weight fibroblast growth factor-2 signals via protein kinase C and myofibrillar proteins to protect against postischemic cardiac dysfunction

Among its many biological roles, fibroblast growth factor-2 (FGF2) acutely protects the heart from dysfunction associated with ischemia/reperfusion (I/R) injury. Our laboratory has demonstrated that this is due to the activity of the low molecular weight (LMW) isoform of FGF2 and that FGF2-mediated cardioprotection relies on the activity of protein kinase C (PKC); however, which PKC isoforms are responsible for LMW FGF2-mediated cardioprotection, and their downstream targets, remain to be elucidated. To identify the PKC pathway(s) that contributes to postischemic cardiac recovery by LMW FGF2, mouse hearts expressing only LMW FGF2 (HMWKO) were bred to mouse hearts not expressing PKCα (PKCαKO) or subjected to a selective PKCε inhibitor (εV(1-2)) before and during I/R. Hearts only expressing LMW FGF2 showed significantly improved postischemic recovery of cardiac function following I/R (P < 0.05), which was significantly abrogated in the absence of PKCα (P < 0.05) or presence of PKCε inhibition (P < 0.05). Hearts only expressing LMW FGF2 demonstrated differences in actomyosin ATPase activity as well as increases in the phosphorylation of troponin I and T during I/R compared with wild-type hearts; several of these effects were dependent on PKCα activity. This evidence indicates that both PKCα and PKCε play a role in LMW FGF2-mediated protection from cardiac dysfunction and that PKCα signaling to the contractile apparatus is a key step in the mechanism of LMW FGF2-mediated protection against myocardial dysfunction.

Targeted delivery of human VEGF gene via complexes of magnetic nanoparticle-adenoviral vectors enhanced cardiac regeneration

This study assessed the concept of whether delivery of magnetic nanobeads (MNBs)/adenoviral vectors (Ad)–encoded hVEGF gene (Ad_hVEGF) could regenerate ischaemically damaged hearts in a rat acute myocardial infarction model under the control of an external magnetic field. Adenoviral vectors were conjugated to MNBs with the Sulfo-NHS-LC-Biotin linker. In vitro transduction efficacy of MNBs/Ad–encoded luciferase gene (Ad_luc) was compared with Ad_luc alone in human umbilical vein endothelial cells (HUVECs) under magnetic field stimulation. In vivo, in a rat acute myocardial infarction (AMI) model, MNBs/Ad_hVEGF complexes were injected intravenously and an epicardial magnet was employed to attract the circulating MNBs/Ad_hVEGF complexes. In vitro, compared with Ad_luc alone, MNBs/Ad_luc complexes had a 50-fold higher transduction efficiency under the magnetic field. In vivo, epicardial magnet effectively attracted MNBs/Ad_hVEGF complexes and resulted in strong therapeutic gene expression in the ischemic zone of the infarcted heart. When compared to other MI-treated groups, the MI-M⁺/Ad_hVEGF group significantly improved left ventricular function (p<0.05) assessed by pressure-volume loops after 4 weeks. Also the MI-M⁺/Ad_hVEGF group exhibited higher capillary and arteriole density and lower collagen deposition than other MI-treated groups (p<0.05). Magnetic targeting enhances transduction efficiency and improves heart function. This novel method to improve gene therapy outcomes in AMI treatment offers the potential into clinical applications.

Impact of low levels of vascular endothelial growth factor after myocardial infarction on 6-month clinical outcome. Results from the Nagoya Acute Myocardial Infarction Study

BACKGROUND

Vascular endothelial growth factor (VEGF) is induced by myocardial ischemia and is thought to facilitate cardiovascular repair after acute myocardial infarction (AMI). However, the association between the plasma VEGF levels and clinical outcome in AMI patients is unclear.

METHODS AND RESULTS

We evaluated 879 AMI patients undergoing successful primary revascularization within 24h of symptom onset. The patients were classified into 3 groups according to tertiles of plasma VEGF levels at 7 days after the onset of AMI. Major adverse cardiovascular and cerebrovascular events (MACCE), defined as cardiac death, recurrent acute coronary syndrome, hospital readmission for heart failure, or stroke, were assessed during the 6-month follow-up period. The incidence of MACCE was the least frequent in the middle tertile. Compared to the middle tertile, patients in the low tertile were at a significantly higher risk for MACCE even after adjusting for baseline characteristics (hazard ratio [HR] 2.67, 95% confidence interval [CI] 1.18-6.06, P=0.019). An absence of statin treatment before onset and a younger age (HR 0.54, 0.87; 95%CI 0.33-0.90, 0.76-0.99; P=0.017, 0.037; respectively) were significantly associated with low VEGF.

CONCLUSIONS

Low plasma VEGF levels at 7 days after the onset of AMI were associated with a significantly increased risk for MACCE during 6 months of follow-up.

Association between circulating monocytes and coronary plaque progression in patients with acute myocardial infarction

BACKGROUND

Monocytes and macrophages have been shown to play major roles in the progression of atherosclerosis. This study examined whether the circulating monocyte count can be used to predict coronary plaque progression of non-culprit intermediate lesions in acute myocardial infarction (AMI).

METHODS AND RESULTS

Intravascular ultrasound findings of non-culprit intermediate plaque in 90 patients were analyzed in the acute phase and at a 7-month follow up. A higher peak monocyte count after AMI was associated with a greater plaque volume change (r=0.32, P=0.002). Multivariate analysis showed that a peak monocyte count of > or =800 /mm(3) was an independent predictor of plaque progression (odds ratio 5.02, P=0.005). High monocyte (> or =800 /mm(3)) at baseline had a higher monocyte count at 7-month follow up than did those with a lower count (368+/-109 vs 263+/-64 /mm(3), P<0.0001). Moreover, the monocyte count at the 7-month follow up was also associated with plaque volume change (r=0.29, P=0.006).

CONCLUSIONS

The results suggest that circulating monocytes play an important role in the progression of coronary plaque in AMI and that the peak monocyte count during hospitalization might be a predictor of plaque progression.

Elevated vascular endothelial growth factor levels are associated with aortopulmonary collateral vessels in patients before and after the Fontan procedure

BACKGROUND

Aortopulmonary collaterals (APCs) are frequently observed before and after the Fontan procedure. However, the mechanism of the development of APCs is unknown. We hypothesized that one or several antiangiogenic and/or angiogenic growth factors might play a role in the development of APCs.

METHODS

Eighty-five patients were enrolled and divided into 3 groups (Fontan group: 30 patients after the Fontan procedure, cyanotic group: 29 patients with cyanotic heart disease, and control group: 26 patients with cyanotic heart disease after biventricular repair). We measured basic fibroblast growth factor, vascular endothelial growth factor (VEGF), hepatocyte growth factor, and endostatin at catheterization. Angiographic evaluation for the presence of APCs using a 4-point scale (grade 1: absent APCs, > or = grade 2: significantly present APCs) was performed, and the relation of the serum levels of these factors to the presence of APCs was assessed.

RESULTS

The grade of APCs significantly increased in the Fontan group, but it decreased in the control group. The serum VEGF levels were higher in the Fontan group (280 +/- 174 pg/mL) and the cyanotic group (302 +/- 245 pg/mL) than in the control group (111 +/- 91 pg/mL) (P = .0004), and they were higher in patients with APCs (383 +/- 204 pg/mL) than in those without APCs (115 +/- 65 pg/mL) (P < .0001). There was no significant difference in the serum basic fibroblast growth factor, hepatocyte growth factor, and endostatin levels between the 3 groups.

CONCLUSIONS

Aortopulmonary collaterals increase after the Fontan procedure. Serum VEGF levels are associated with the presence of APCs. Vascular endothelial growth factor may play a role in the development of APCs in patients with cyanotic heart disease and after the Fontan procedure.

Intramyocardial injection of low-dose basic fibroblast growth factor or vascular endothelial growth factor induces angiogenesis in the infarcted rabbit myocardium

BACKGROUND

Myocardial angiogenesis after the systemic administration of basic fibroblast growth factor or vascular endothelial growth factor at high therapeutic doses has been implicated in the occurrence of side effects that may undermine their safety. The aim of this study was to investigate the angiogenic effects of the intramyocardial administration of recombinant human basic fibroblast growth factor or vascular endothelial growth factor protein, at low doses, in the infarcted rabbit myocardium.

METHODS AND RESULTS

Twenty-five New Zealand White rabbits were divided into five groups (n=5) and subjected to coronary artery ligation after lateral thoracotomy, inducing acute myocardial infarction. Five minutes later, the following substances were injected intramyocardially into the infarcted area: (a) normal saline (controls); (b) 6.25 or 12.5 mug of recombinant human basic fibroblast growth factor protein (basic fibroblast growth factor-1 group or basic fibroblast growth factor-2 group); or (c) 5 or 10 microg of recombinant human vascular endothelial growth factor 165 protein (vascular endothelial growth factor-1 group or vascular endothelial growth factor-2 group). On the 21st postoperative day, the animals were euthanized, and their hearts were subjected to histopathological examination and immunohistochemical assessment of vascular density in the infarcted area. The alkaline phosphatase anti-alkaline phosphatase procedure and the primary monoclonal antibody JC70 were used. Histopathological examination confirmed the induction of myocardial infarction. Vascular density was significantly increased (P<.004) in all treatment groups (in mean+/-S.E. vessels/x 200 optical field: basic fibroblast growth factor-1: 85.8+/-10.9; basic fibroblast growth factor-2: 76.6+/-3.7; vascular endothelial growth factor-1: 73.4+/-3.2; vascular endothelial growth factor-2: 89.5+/-5.2) compared to that in controls (58.9+/-4.9 vessels/x 200 optical field). Vascular density in the vascular endothelial growth factor-2 group was significantly higher than that in the vascular endothelial growth factor-1 group (P<.001).

CONCLUSIONS

Low doses of recombinant human basic fibroblast growth factor or vascular endothelial growth factor protein, when administered intramyocardially, stimulate angiogenesis in the infarcted myocardium.

A strategy of retrograde injection of bone marrow mononuclear cells into the myocardium for the treatment of ischemic heart disease

OBJECTIVE

Bone marrow cells implantation (BMI) has been reported to efficiently improve ischemic heart disease. However, BMI strategies are generally invasive. To establish a BMI strategy for ischemic heart disease, we performed implantation of autologous cryopreserved mononuclear cells (MNCs) from bone marrow (BM) retrogradely into the myocardium via the coronary vein in pigs with acute myocardial infarction (AMI) and old myocardial infarction (OMI).

METHODS

BM cells were harvested from the pigs' fumurs. MNCs were collected by centrifugation and were cryopreserved. Anterior myocardial infarction was induced by occlusion of the midportion of the left anterior descending coronary artery without surgical intervention. Frozen BM cells were quickly thawed and injected retrogradely via the coronary vein into the myocardium through a single balloon infusion catheter 6 h and 2 weeks after the induction of infarction. Four weeks after implantation, coronary arteriograms were obtained, cardiac function was analyzed with the use of a conductance catheter, and histopathologic analysis was performed with a confocal laser microscope. Plasma levels of natriuretic peptides and angiogenic growth factors were measured after BMI.

RESULTS

Flow cytometric analysis revealed that 90% of cryopreserved BM cells were viable in vitro. Labeled BM cells were entirely distributed around in the infarcted area of maycardium in pigs. BMI increased collateral neovascuralization in infarcted hearts. BMI significantly improved cardiac function in AMI with BMI and OMI with BMI groups. BMI also increased the formation of microcapillary arteries in infarcted hearts. Levels of natriuretic peptides were significantly decreased, and levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF2) were significantly increased after BMI. Confocal laser microscopy revealed the presence of proliferative and activated myocardial cells in infarcted hearts after BMI.

CONCLUSION

The retrograde infusion of cryopreserved BM cells into myocardium efficiently induced angiogenesis and improved cardiac function in pigs with AMI or OMI. These results suggest that the present strategy of BMI will be safe and feasible as an angiogenic cell therapy for ischemic heart disease.

Effects of Total Coronary Artery Occlusion on Vascular Endothelial Growth Factor and Transforming Growth Factor β

Vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta1) play an important role in angiogenesis. We wanted to determine if concentrations of growth factors in the coronary sinus (CS) and right atrium (RA) are higher in coronary artery disease patients with total occlusions than in those with partial occlusions. Fifty-one patients scheduled for coronary artery angiography were evaluated for possible recruitment. A 6F Goodale-Lubin catheter was used to collect blood from the CS and RA. Data for all but four patients were gathered successfully, leaving 47 study patients. The reviewer was blinded to growth factor data when interpreting coronary angiographic findings. Of the 47 enrolled patients, 32 had at least one diseased vessel, seven of whom had at least one major total epicardial coronary occlusion. In all 32 patients, the concentrations of VEGF in the CS were higher than those in the RA (31.5 +/- 2.7 vs 27.1 +/- 1.8 pg/mL; p = 0.005). Patients with total occlusions had higher VEGF concentrations in the CS than those with non-total occlusions (38.9 +/- 8.0 vs 29.5 +/- 2.6 pg/mL; p = 0.037). The differences in TGF-beta1 in the two groups were not statistically significant. The higher CS VEGF concentrations in patients with total occlusion indicate that VEGF may play a part in the development of angiogenesis.

Bradycardia Induces Angiogenesis, Increases Coronary Reserve, and Preserves Function of the Postinfarcted Heart

Background— We tested the hypothesis that induction of chronic bradycardia would trigger an upregulation of key growth factors and receptors, which would then lead to angiogenesis and improve coronary reserve in the left ventricle after myocardial infarction.

Methods and Results— Bradycardia was induced in rats by administering alinidine via osmotic pumps beginning 1 day after coronary artery ligation. Echocardiographic analysis was conducted before and after treatment. Morphometric analysis was used in perfusion-fixed hearts to document arteriolar and capillary growth. Western blots were used to evaluate growth factor and receptor changes. During the first week of treatment, vascular endothelial growth factor (VEGF), VEGF receptor 1 (Flt-1), and basic fibroblast growth factor proteins were higher in the treated group, whereas VEGF receptor 2 (Flk-1), angiopoietin-1, and angiopoietin-2 were not affected by treatment. After 3 weeks, VEGF protein remained elevated, and bradycardia was associated with a higher capillary length density in the border (40%) and remote (14%) regions and a higher arteriolar length density in the septum (62%), despite a greater increase in left ventricular mass. Although arteriolar length density increased in all size classes, the greatest increase occurred in the smallest (terminal) arterioles. This vascular growth was associated with a 23% greater coronary reserve. Echocardiography revealed a smaller increase in ventricular volume and a greater preservation of ejection fraction in rats treated with bradycardia.

Conclusions— Pharmacologic induction of bradycardia enhances vascularity and coronary reserve, preserves function of surviving myocardium, and therefore, is a noninvasive, therapeutic avenue that provides an alternative to gene therapy.

Thromboxane A2 receptor signaling inhibits vascular endothelial growth factor-induced endothelial cell differentiation and migration

Vascular endothelial growth factor (VEGF) is an important patho-physiological mediator of angiogenesis. VEGF-induced endothelial cell (EC) migration and angiogenesis often occur in complicated environments containing multiple agents capable of modifying the response. Thromboxane (TX) A2 is released from multiple cell types and is a prime mediator of pathogenesis of many vascular diseases. Human EC express both TXA2 receptor (TP) isoforms; however, the effects of individual TP isoforms on VEGF-induced EC migration and angogenesis are unknown. We report here that the TXA2 mimetic [1S-(1alpha, 2beta(5Z), 3alpha(1E, 3R), 4alpha]-7-[3-(3-hydroxy-4-(4'-iodophenoxy)-1-butenyl)-7-oxab icyclo-[2.2.1]heptan-2yl]-5'-heptenoic acid (IBOP) (100 nmol/L) is a potent antagonist (IC50 30 nmol/L) of VEGF-induced EC migration and differentiation. TPbeta, but not TPalpha, expression is required for the inhibition of VEGF-induced migration and angiogenesis. IBOP costimulation suppressed nitric oxide (NO) release from VEGF-treated EC through decreased activation of Akt, eNOS, and PDK1. TPbeta costimulation also ablated the increase in focal adhesion formation in response to VEGF. This mechanism was characterized by decreased recruitment of focal adhesion kinase (FAK) and vinculin to the alpha(v)beta3 integrin and reduced FAK and Src activation in response to VEGF. Addition of NO donors together with transfection of a constitutively active Src construct could circumvent the blockade of VEGF-induced migration by TP; however, neither intervention alone was sufficient. Thus, TP stimulation appears to limit angiogenesis, at least in part, by inhibiting the pro-angiogenic cytokine VEGF. These data further support a role for antagonism of TP activation in enhancing the angiogenic response in tissues exposed to elevated TXA2 levels in which revascularization is important.

Thromboxane A 2 Receptor Agonists Antagonize the Proangiogenic Effects of Fibroblast Growth Factor-2

Thromboxane (TX) A 2 is released from multiple cell types and is a prime mediator of the pathogenesis of many vascular events, including angiogenesis. Endothelial cells express TXA 2 receptors (TP) but the effects of TP stimulation on angiogenesis remain controversial. In this study, we show that stimulation of endothelial cell TP impairs ligand-induced FGF receptor internalization and consequently abrogates FGF-2-induced endothelial cell migration in vitro and angiogenesis in vivo. Prevention of FGF-2-induced angiogenesis was associated with expression of the TPβ isoform. The deficit in FGFR1 internalization was mediated through activation of TPβ preventing the FGF-2-mediated decrease in p53 expression, thus enhancing thrombospondin-1 (TSP-1) release from EC and reducing FGFR1 internalization. Once released TSP-1 interacted with the α v β 3 integrin on the EC surface. On stimulation, FGFR1 and α v β 3 were found to associate in a complex. We determined that complex formation was important for receptor internalization as conditions that inhibit FGFR1 internalization, such as inappropriate ligation of α v β 3 by either TSP-1 or a neutralizing antibody, disrupted the complex. These results establish a novel role for isoform specific regulation of angiogenesis by TP, provide the first functional significance for the existence of two TP isoforms in humans, and clarify the mechanism by which TP signaling regulates FGFR1 kinetics and signaling.

Concentrations of Hepatocyte Growth Factor, Basic Fibroblast Growth Factor, and Vascular Endothelial Growth Factor in Pericardial Fluid and Plasma

Some angiogenic factors, including hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF), have been reported to promote angiogenesis and improve myocardial perfusion in experimental models of ischemic heart disease. These factors are produced in various tissues, including myocardium. We measured the concentrations of HGF, bFGF, and VEGF by enzyme-linked immunosorbent assay in plasma and in pericardial fluid sampled during open heart surgery (12 patients with ischemic heart disease and 17 with nonischemic heart disease). HGF levels were significantly higher in plasma than in pericardial fluid (12.0 +/- 1.8 versus 0.26 +/- 0.04 ng/mL, P < 0.0001). On the other hand, bFGF levels were significantly higher in pericardial fluid than in plasma (243.5 +/- 50.9 versus 49.6 +/- 7.8 pg/mL, P = 0.009). VEGF levels were not significantly different between pericardial fluid and plasma (47.2 +/- 17.6 versus 24.5 +/- 3.6 pg/mL, P = 0.23). Concentrations of angiogenic factors in pericardial fluid and in plasma were not significantly different between patients with ischemic and nonischemic heart disease. These results suggest that the production, secretion, and kinetics of HGF, bFGF, and VEGF are different. These angiogenic factors may have different pathophysiologic roles.

Hepatocyte growth factor and vascular endothelial growth factor in ischaemic heart disease

BACKGROUND

Hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) are endothelial cell-specific growth factors, but the production of these growth factors in cardiomyocytes has also been demonstrated. However, there have been no reports focusing their attention on the changes in these growth factors after coronary intervention. We investigated the time-course changes of the serum VEGF and HGF levels in angina pectoris (AP) and acute myocardial infarction (AMI).

METHODS

The serum HGF and VEGF levels were measured in 60 patients with AP, in 62 patients with AMI (AP, before heparin administration, and at 24 and 48 hours, and one week after intervention; AMI, before heparin, and at 48 and 72 hours, and one, two, three and four weeks) and in 56 patients with neurocirculatory asthenia as controls. We defined the patients with remodelling who showed an increase in left ventricular end-diastolic volume index (LVEDVI) in the sub-acute phase of AMI.

RESULTS

Hepatocyte growth factor levels in the AP and AMI were significantly higher than that in the control (p<0.0001). The AMI level was also significantly higher than AP (p<0.001). In the AMI and AP, HGF peaked at 48 hours. Vascular endothelial growth factor level in the AMI was significantly higher than that in the control and AP (p<0.0001). In the AMI, VEGF peaked at two weeks. There was a significant positive correlation between the peak VEGF and LVEDVI in the sub-acute phase of AMI (p=0.0089, r=0.436). Peak VEGF in the remodelling (+) group was significantly higher than that in the remodelling (-) group (p<0.001). In the AP, VEGF was unchanged.

CONCLUSION

While both myocardial and vascular damage contribute to an increase in HGF level, vascular damage is not associated with the increase in VEGF. Vascular endothelial growth factor might be related to left ventricular remodelling in the sub-acute phase of myocardial infarction.

Serum hepatocyte growth factor predicts ventricular remodeling following myocardial infarction

Hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) stimulate endothelial cell proliferation and induce angiogenesis, but the timing and significance of their release in patients with acute myocardial infarction (AMI) are unknown in relation to future left ventricular remodeling. Venous blood samples were obtained at admission and up to 3 weeks later in 40 patients with AMI and in 40 age- and sex-matched control subjects. Blood samples were also taken from the coronary sinus (CS) in 20 patients on day 7 following AMI. Left ventricular end-diastolic volume in the subacute (1 week) and chronic (3 months) phases was assessed by left ventriculography to identify the remodeling group (n=15), which was defined as an increase in left ventricular end-diastolic volume index > or =5 ml/m(2) relative to the baseline value. Serum HGF and VEGF concentrations were higher in newly admitted patients with AMI than in the controls (HGF, 0.33 +/-0.09 vs 0.24+/-0.08 ng/ml, p<0.01; VEGF, 92.2+/-43.1 vs 67.2+/-29.8 pg/ml, p<0.01), peaking on day 7 (HGF, 0.41+/-0.12; VEGF, 161.7+/-76.9), and gradually decreasing between days 14 and 21. The HGF concentration in the CS did not differ from the concentration in the periphery, but the VEGF concentration was significantly more abundant in the CS than in the peripheral sample on day 7 (p<0.05). The serum HGF concentration on day 7 was higher in the remodeling group than in the nonremodeling group (0.47 +/-0.13 vs 0.36+/-0.09 ng/ml, p<0.01), but there was no difference between the groups on admission, day 14 and day 21. The serum VEGF concentration did not differ between the remodeling and nonremodeling groups at any time. Thus, the serum HGF concentration on day 7 after AMI is mostly from noncardiac sources and predicts left ventricular remodeling.

Plasma vascular endothelial growth factor in sleep apnea syndrome: effects of nasal continuous positive air pressure treatment

Sleep apnea syndrome is associated with recurrent episodic hypoxia during sleep, which has been implicated in the development of cardiovascular morbidity. Hypoxia is the major stimulus of vascular endothelial growth factor (VEGF), which is a potent angiogenic cytokine. In the present article we describe the results of three experiments in which plasma concentrations of VEGF were measured in patients with sleep apnea. In Experiment 1, apnea-hypopnea index was found to be a significant independent predictor of morning VEGF concentrations in 85 male subjects investigated in the sleep laboratory, of whom 47 had an apnea-hypopnea index greater than 20. In Experiment 2, VEGF concentrations measured hourly during the sleep period were found to be significantly higher in a group of five sleep apnea patients compared with six age-similar snorers and six normal young adults (129.1 +/- 43.4 versus 74.6 +/- 11.5 and 32.5 +/- 12.8 pg/ml, respectively [p < 0.007]). In Experiment 3, VEGF concentrations were compared in patients with sleep apnea before and 1 year after nasal continuous positive airway pressure treatment. A significant decrease in VEGF concentrations was found only in patients in whom nocturnal hypoxia improved after treatment (57.1 +/- 62.5 versus 39.6 +/- 46.9 pg/ml, p < 0.01). There was no comparable improvement in patients who did not accept treatment (53.9 +/- 23.6 versus 54.0 +/- 21.5 pg/ml, ns). These results raise the possibility that VEGF may contribute to the long-term adaptation of sleep apnea syndrome to recurrent nocturnal hypoxia.

Increased vascular endothelial growth factor expression in human hearts with microvascular fibrin

We have shown that microvascular changes that promote fibrin deposition in human cardiac allografts adversely affect clinical outcome. However, some allografts exhibit phenotypic changes in capillaries following the deposition of fibrin, which subsequently provide a significant survival advantage. The mechanism(s) involved in these capillary changes is(are) unknown. Similarly, although we have shown a significant temporal relationship between microvascular fibrin deposition and vascular endothelial growth factor (VEGF) immunoreactivity in cardiac allografts, the cellular source and relative changes in VEGF gene expression under these conditions are not known. Using immunocytochemical techniques, biopsies devoid of fibrin deposition lacked detectable VEGF immunoreactivity, whereas biopsies with fibrin deposition showed VEGF immunoreactivity in cardiocytes, interstitium, and some microvessels. By in situ hybridization, biopsies without microvascular fibrin deposition showed faint VEGF hybridization signals confined primarily to cardiocytes. In biopsies with fibrin deposition, strong VEGF hybridization signals were detected in cardiocytes, arteriolar smooth muscle cells were occasionally labeled, and endothelial cells were rarely labeled. By quantitative RT-PCR, biopsies with fibrin deposition (n=5) relatively expressed approximately three-fold more VEGF mRNA than biopsies without fibrin deposition (n=5 P=0.02). Serum VEGF titers also were greater (P=0.01) in recipients with fibrin deposition (372.9+/-66.7 pg/ml n=18) compared to recipients without fibrin deposition (172.1+/-25.0 pg/ml n=16). Collectively, these results support the hypothesis that increased myocyte-derived VEGF production following microvascular fibrin deposition in transplanted human hearts may act in a paracrine manner to promote activational and phenotypic changes in capillaries that provide a survival advantage for the allografts.

Serial changes in serum VEGF and HGF in patients with acute myocardial infarction

The time course of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) release in patients with acute myocardial infarction (AMI) is unknown. Blood samples were obtained at the time of admission and 3, 7, 14 and 21 days later in 32 patients with AMI and 30 control patients. Serum VEGF and HGF, as well as C-reactive protein (CRP) and amyloid A protein (SAA), were determined. Both serum VEGF and HGF levels on admission in patients with AMI were higher than control values and peaked on day 7. VEGF levels in patients with preinfarction angina were higher than in patients with no preinfarction angina, whereas the HGF level did not differ. Both CRP and SAA levels peaked on day 3, and the CRP level on day 3 correlate with both VEGF and HGF levels on day 7. We hypothesized that the serum VEGF level is associated with preinfarction ischemia and the increase in VEGF and HGF on day 7 of AMI may represent a response to acute inflammation.