Lenvatinib Plus Anti-PD-1 Combination Therapy for Advanced Cancers: Defining Mechanisms of Resistance in an Inducible Transgenic Model of Thyroid Cancer.

Background: Combination therapy with lenvatinib plus programmed death-1 (PD-1) immune checkpoint blockades (ICBs) is under investigation in many solid tumors, including thyroid cancer. Lenvatinib is known to reduce angiogenesis and may overturn the immunosuppressive effects of vascular endothelial growth factor in the tumor microenvironment. Previous studies investigating the effects of VEGF receptor inhibition on the immune response were performed in rapidly growing tumor models where immune equilibrium is not established before treatment. We hypothesize that physiologically relevant preclinical models are necessary to define mechanisms of resistance to immune-targeted combination therapies. Methods: We utilized the TPO-CreER/BrafV600E/wt/Trp53Δex2-10/Δex2-10 inducible transgenic model of advanced thyroid cancer to investigate lenvatinib treatment in the context of an anti-PD-1 ICB. Following tumor establishment, 3.5 months postinduction, mice were treated with high- (10 mg/kg) or low-dose (2 mg/kg) lenvatinib, anti-PD-1, or combination of lenvatinib with anti-PD-1. Tumor volume and lung metastases were assessed in each group. Immune infiltrate was characterized by flow cytometry and immunohistochemistry, and TCRß sequencing was performed to further investigate the T cell response. Results: Both low- and high-dose lenvatinib reduced tumor volume, while anti-PD-1 had no effect, alone or in combination. Although both low- and high-dose lenvatinib reduced vascular density, low-dose lenvatinib was superior in controlling tumor size. Lung metastases and survival were not improved with therapy despite the effects of lenvatinib on primary tumor size. Low-dose lenvatinib treatment led to a subtle reduction in the dominant Ly6G+CD11b+ myeloid cell population and was associated with increased CD4+ T cell infiltrate and enrichment in 4-1BB+ and granzyme B+ CD4+ T cells and FoxP3+ regulatory T cells. Polyclonal T cell expansion was evident in the majority of mice, suggesting that a tumor-specific T cell response was generated. Conclusions: The effects of lenvatinib on the immune response were most pronounced in mice treated with low-dose lenvatinib, suggesting that dose should be considered in clinical application. While the immune-modulating potential of lenvatinib is encouraging, alterations in the immune milieu and T cell activation status were insufficient to sustain durable tumor regression, even with added anti-PD-1. Additional studies are necessary to develop more effective combination approaches in low-mutation burden tumors, such as thyroid cancer.

Development of VEGF-loaded PLGA matrices in association with mesenchymal stem cells for tissue engineering.

The association of bioactive molecules, such as vascular endothelial growth factor (VEGF), with nanofibers facilitates their controlled release, which could contribute to cellular migration and differentiation in tissue regeneration. In this research, the influence of their incorporation on a polylactic-co-glycolic acid (PLGA) scaffold produced by electrospinning on cell adhesion and viability and cytotoxicity was carried out in three groups: 1) PLGA/BSA/VEGF; 2) PLGA/BSA, and 3) PLGA. Morphology, fiber diameter, contact angle, loading efficiency and controlled release of VEGF of the biomaterials, among others, were measured. The nanofibers showed smooth surfaces without beads and with interconnected pores. PLGA/BSA/VEGF showed the smallest water contact angle and VEGF released for up to 160 h. An improvement in cell adhesion was observed for the PLGA/BSA/VEGF scaffolds compared to the other groups and the scaffolds were non-toxic for the cells. Therefore, the scaffolds were shown to be a good strategy for sustained delivery of VEGF and may be a useful tool for tissue engineering.

Electrospun scaffolds functionalized with heparin and vascular endothelial growth factor increase the proliferation of endothelial progenitor cells.

In severe cases of peripheral arterial disease, tissue loss can occur and the use of vascular grafts can be necessary. However, currently, there are no suitable substitutes for application in small diameter vessels. The aim of this work has been to produce scaffolds with adequate properties for application as vascular substitutes. Polycaprolactone scaffolds were produced by the electrospinning technique. The surface of the scaffolds was functionalized with heparin and vascular endothelial growth factor (VEGF) and their physical-chemical properties were characterized. Human endothelial progenitor cells (EPCs) or mesenchymal stem cells (MSCs) were seeded onto the surface of the scaffolds in order to create an endothelial layer. The electrospun scaffolds exhibited mechanical properties compatible with the native arteries. The presence of heparin prevented blood coagulation on the scaffold surface. The presence of heparin and VEGF favored the adaptation of MSCs and EPCs on the scaffolds in relation to the non functionalized scaffolds. In addition, the EPCs cultivated on the scaffolds maintained the expression of CD31, CD34 and VE-cadherin genes. The results obtained in the present study suggest that electrospun scaffolds functionalized with heparin and VEGF can be applied in vascular tissue engineering. These scaffolds exhibited antithrombogenic properties and favored the development of cells on their surface. The association of heparin and VEGF with electrospun scaffolds increased EPC proliferation, favoring the formation of the endothelial layer and the regeneration of damaged vessels.

Development of VEGF-loaded PLGA matrices in association with mesenchymal stem cells for tissue engineering

The association of bioactive molecules, such as vascular endothelial growth factor (VEGF), with nanofibers facilitates their controlled release, which could contribute to cellular migration and differentiation in tissue regeneration. In this research, the influence of their incorporation on a polylactic-co-glycolic acid (PLGA) scaffold produced by electrospinning on cell adhesion and viability and cytotoxicity was carried out in three groups: 1) PLGA/BSA/VEGF; 2) PLGA/BSA, and 3) PLGA. Morphology, fiber diameter, contact angle, loading efficiency and controlled release of VEGF of the biomaterials, among others, were measured. The nanofibers showed smooth surfaces without beads and with interconnected pores. PLGA/BSA/VEGF showed the smallest water contact angle and VEGF released for up to 160 h. An improvement in cell adhesion was observed for the PLGA/BSA/VEGF scaffolds compared to the other groups and the scaffolds were non-toxic for the cells. Therefore, the scaffolds were shown to be a good strategy for sustained delivery of VEGF and may be a useful tool for tissue engineering.

Análisis de impacto presupuestal de ranibizumab comparado con aflibercept, triamcinolona y bevacizumab para tratamiento de pacientes con edema macular secundario a oclusión de la vena central de retina en Colombia / Ranibizumab budget impact analysis compared to aflibercept, triamcinolone and bevacizumab for treatment of patients with macular edema secondary to central retinal vein occlusion in Colombia

Tecnologías evaluadas: Intervención: Ranibizumab; Comparadores: Aflibercept, triamcinolona y bevacizumab. Población: Pacientes con edema macular secundario a oclusión de la vena central de la retina en Colombia. \r\nPerspectiva: Tercer pagado - Sistema General de Seguridad Social en Salud (SGSSS). Horizonte temporal: \r\nEl horizonte temporal de este AIP en el caso base corresponde a un año. Adicionalmente, se reportan las\r\nestimaciones del impacto presupuestal para los años 2 y 3, bajo el supuesto de la inclusión en el POS en el año 1. Costos incluidos: Costo de medicamentos; Costos de procedimientos e insumos. Fuente de costos: SISMED; Manual tarifario ISS 2001. Escenarios: Escenario 1: El costo de los medicamentos permanece igual al actual. El uso de bevacizumab sería de 85%, aflibercept sería del 10%, triamcinolona podría ocupar el 15 % restante Escenario 2: tanto el costo de ranibizumab como el de aflibercept se ajustan al valor de bevacizumab. Ante esta situación, la utilización de aflibercept sería del 50%, ranibizumab y bevacizumab tomarían un 22.5% de participación cada uno y triamcinolona el restante 5%. Resultados: El impacto presupuestal total e incremental al que el sistema de salud colombiano estaría incurriendo al incluir los\r\nmedicamentos ranibizumab, aflibercept, bevacizumab y triamcinolona dentro del plan de beneficios para el tratamiento de edema macular secundario a OVCR bajo las condiciones de caso base este valor sería de 25.716 millones de pesos para el primer año de adopción. Para el segundo y tercer año el impacto incremental sería superior a los 6 y 8 mil millones de pesos respectivamente. (AU)

Análisis de impacto presupuestal de ranibizumab, aflibercept y bevacizumab, para tratamiento de pacientes con degeneración macular relacionada a la edad en Colombia / Análise de impacto orçamentário de ranibizumab, aflibercept e bevacizumab para o tratamento de pacientes com degeneração macular relacionada à idade na Colômbia

Tecnologías evaluadas: Intervención: Ranibizumab; Comparadores: Aflibercept y bevacizumab. Población: Pacientes con degeneración macular relacionada a la edad en Colombia. Perspectiva: Tercer pagador, el Sistema General de Seguridad Social en Salud (SGSSS). Horizonte temporal: El horizonte temporal de este AIP en el caso base corresponde a un año. Adicionalmente, se reportan las estimaciones del impacto presupuestal para los años 2 y 3, bajo el supuesto de la inclusión en el POS en el año 1. Costos incluidos:\tCosto de medicamentos; \tCostos de procedimientos e insumos. Fuente de costos: SISMED; Manual tarifario ISS 2001. Escenarios: Escenario 1: inclusión de todos los medicamentos al POS sin\r\ncambio en las características del mercado (precios), participación del bevacizumab del 100%; Escenario 2: inclusión de todos los medicamentos al POS con ajustes en los precios del ranibizumab y aflibercept, la\r\nparticipación será del 33.3% para cada uno de los medicamentos. Resultados: Bajo las condiciones actuales, el esfuerzo presupuestal que del SGSSS al incluir los tres medicamento al plan de beneficios se\r\nestima en 1.3 billones de pesos para el primer año de adopción; Este incrementaría en 348 y 448 mil millones de pesos para el segundo y tercer año respectivamente.(AU)

Development of an experimental model of proliferative retinopathy by intravitreal injection of VEGF165.

PURPOSE: To develop an experimental model of proliferative retinopathy by intravitreal injection of vascular endothelial growth factor 165 (VEGF165) in pigmented rabbits. METHODS: A prospective, controlled, comparative intervention study. Six pigmented rabbits (Chinchilla breed) were subjected to intravitreal injection of VEGF165 in their right eye. The left eye was used as control and received an injection of balanced salt solution. In group 1, 3 rabbits received a 10-µg injection, and in group 2, 3 rabbits received a 20-µg injection. At baseline, all subjects were analyzed by anterior biomicroscopy, retinography, fluorescein angiography, and optical coherence tomography (OCT) fundus images. Biomicroscopy and all ancillary examinations were repeated at weeks 1, 2, and 5. In the fifth week after the injection, the rabbits were euthanized and the eyes were enucleated and subjected to histological evaluation. RESULTS: Seven days after the intravitreal VEGF165 injection, all rabbits developed intense neovascularization of the retina and anterior segment. Neovascularization of the posterior pole was similar in both groups, and the anterior segment was more florid in group 2. At weeks 1 and 2, neovascularization persisted with a minor decrease in conjunctival hyperemia in both groups. At week 5, there was a partial regression of neovascularization of the posterior pole, which was more prominent in group 1 than group 2, with persistent anterior neovascularization in both groups. OCT showed a statistically significant increase in retinal thickness, hyaloid detachment, and tractional retinal detachment. After the 5-week period, ocular histopathological evaluation showed an increase in retinal thickness, hyaloid detachment, and intense neovascularization in both groups, especially group 2. CONCLUSION: This pilot study of a neovascularization model using intravitreal injection of VEGF165 in pigmented rabbits showed that both doses of 10 and 20 µg were successful and effective in inducing vascular growth in the retina and anterior segment and can therefore be used for evaluating drug efficacy in future studies.

Combined VEGF gene transfer and erythropoietin in ovine reperfused myocardial infarction.

BACKGROUND: In reperfused acute myocardial infarction (RAMI), cardioprotective treatments may enhance myocardial salvage and hence reduce the area of necrosis. Based on studies showing that plasmid-mediated vascular endothelial growth factor (pVEGF) gene transfer reduces infarct size by combining angio-arteriogenic and cardiomyogenic effects and that erythropoietin (EPO) exerts anti-apoptotic actions in animal models of AMI, we aimed to assess if their association would reduce infarct size to a larger extent than any of them individually in a large mammalian model of RAMI. METHODS: Adult sheep subjected to 90-minute coronary artery occlusion received upon reperfusion intramyocardial pVEGF 3.8 mg plus intravenous EPO 1000 IU/kg (n=8), pVEGF (n=8), EPO (n=8) or placebo (n=8). RESULTS: Fifteen days after treatment, infarct size was smaller in the 3 treatment groups (pVEGF+EPO: 8 ± 1 %; pVEGF: 16 ± 5 %; EPO: 13 ± 4 %) compared to placebo (25 ± 7 %, p<0.001). However, in the EPO+VEGF group infarct size was significantly smaller than in the groups receiving EPO or VEGF individually (p<0.05). DNA fragmentation, a hallmark of late apoptosis, was significantly lower in sheep receiving EPO. The combined treatment, while not affecting global left ventricular performance, improved regional peri-infarct function and prevented over-time expansion of the post-infarct perfusion defect. CONCLUSIONS: Combined pVEGF and EPO treatment might be clinically useful to enhance the benefits of early revascularization in patients with acute myocardial infarction.

Delayed administration of VEGF rescues spinal motor neurons from death with a short effective time frame in excitotoxic experimental models in vivo.

VEGF (vascular endothelial growth factor) prevents neuronal death in different models of ALS (amyotrophic lateral sclerosis), but few studies have addressed the efficacy of VEGF to protect motor neurons after the onset of symptoms, a critical point when considering VEGF as a potential therapeutic target for ALS. We studied the capability of VEGF to protect motor neurons after an excitotoxic challenge in two models of spinal neurodegeneration in rats induced by AMPA (α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) administered either chronically with osmotic minipumps or acutely by microdialysis. VEGF was administered through osmotic minipumps in the chronic model or injected intracerebroventricularly in the acute model, and its effects were assessed by immunohistochemical and histological analyses and motor performance tests. In the chronic model, VEGF stopped the progression of the paralysis and protected motor neurons when administered after AMPA before the onset of the motor symptoms, whereas no protection was observed when administered after the onset. VEGF was also protective in the acute model, but with a short time window, since the protection was effective when administered 1 h but not 2 h after AMPA. Our results indicate that while VEGF has an indubitable neuroprotective effect, its therapeutic potential for halting or delaying the progression of motor neuron loss in ALS would likely have a short effective time frame.

Vascular therapy for radiation cystitis.

PURPOSE: The underlying pathology of radiation cystitis is cellular and vascular damage followed by increased fibrosis and inflammation. This study was to determine if neovascular-promoting therapy could reduce the pathological changes in the bladder wall associated with pelvic irradiation. METHODS: Adult female Lewis inbred rats were irradiated with a single dose of 20 Gy directed at their bladder. Four weeks later, 30 rats were divided equally into one of three treatment groups for bladder wall injection of: (1) PBS (Control); (2) PBS containing 50 ng vascular endothelial growth factor (VEGF (165)); or (3) PBS containing 1 × 10(6) rat endothelial cells (EC). Age-matched non-irradiated rats (n = 10) served as untreated controls. At either 1.5 or 3 months following radiation, bladders were analyzed for collagen deposition using Masson's Trichrome staining of collagen and muscle and vascularization using Von Willebrand factor staining of ECs. Quantitative-PCR was used to examine markers of angiogenesis, hypoxia, and fibrosis. RESULTS: The collagen/muscle ratio was doubled in the control group 3 months post-irradiation (P < 0.05 vs. non-irradiated bladders). Both ECs and VEGF inhibited increases in collagen content (P < 0.05 vs. control). Similarly, irradiation reduced bladder wall vessel counts compared to non-irradiated controls (P < 0.05) and both ECs and VEGF maintained vessel counts similar to that of non-irradiated controls (P < 0.05). PCR analysis showed a higher expression of neovascular markers (CD31, KDR) in the EC and VEGF groups compared to non-irradiated controls (P < 0.05). CONCLUSIONS: Angiogenesis therapy may be useful in the prevention and/or treatment of the underlying pathology of radiation cystitis.

VEGF gene therapy for angiogenesis in refractory angina: phase I/II clinical trial.

OBJECTIVE: Safety, feasibility and early myocardial angiogenic effects evaluation of transthoracic intramyocardial phVEGF165 administration for refractory angina in no option patients. METHODS: Cohort study, in which 13 patients with refractory angina under optimized clinical treatment where included, after cineangiograms had been evaluated and found unfeasible by surgeon and interventional cardiologist. Intramyocardial injections of 5 mL solution containing plasmidial VEGF165 where done over the ischemic area of myocardium identified by previous SPECT/Sestamibi scan. Evaluations included a SPECT scan, stress test, Minnesota QOL questionnaire and NYHA functional class and CCS angina class determinations. RESULTS: There were no deaths or new interventions during the study period. There were no significant variations in SPECT scans, QOL scores and stress tests results during medical treatment in the included patients. After the 3rd post operative month, there was improvement in SPECT segmental scores, SSS (18.38 ± 7.51 vs. 15.31 ± 7.29, P = 0.003) and SRS (11.92 ± 7.49 vs. 8.53 ± 6.68, P = 0.002). The ischemic area extension, however, had non-significant variation (23.38 ± 13.12% vs. 20.08 ± 13.88%, P = 0.1). Stress tests METs varied from 7.66 ± 4.47 pre to 10.29 ± 4.36 METs post-op (P = 0.08). QOL score improved from 48.23 ± 18.35 pre to 30.15 ± 20.13 post-op points (P = 0.02). NYHA class was 3.15 ± 0.38 pre vs. 1.77 ± 0.83 post-op (P = 0.001) and angina CCS class, 3.08 ± 0.64 vs. 1.77 ± 0.83 (P = 0.001). CONCLUSIONS: Intramyocardial VEGF165 therapy for refractory angina, in this small trial of no option patients, resulted feasible and safe. Early clinical and scintilographic data showed improvements in symptoms and myocardial perfusion, with regression of ischemia severity in treated areas.

Terapia gênica com VEGF para angiogênese na angina refratária: ensaio clínico fase I/II / VEGF gene therapy for angiogenesis in refractory angina: phase I/II clinical trial

OBJETIVO: Avaliar a segurança, viabilidade e efeitos iniciais, clínicos e sobre a perfusão miocárdica, da administração intramiocárdica, transtorácica, de VEGF 165 plasmidial em pacientes com doença arterial coronariana avançada e angina refratária, não passíveis de revascularização percutânea e cirúrgica. MÉTODOS: Ensaio clínico fase I/II. Treze pacientes cardiopatas isquêmicos com angina refratária apesar de tratamento medicamentoso máximo por no mínimo seis meses, não passíveis de revascularização cirúrgica ou por cateter foram submetidos a injeções intramiocárdicas de 2000µg VEGF 165 plasmidial. Os pacientes foram avaliados por cintilografia miocárdica, teste ergométrico, questionário de qualidade de vida (Minnesota) e determinação das classes de insuficiência cardíaca (NYHA) e angina (CCS). RESULTADOS: Não houve óbitos ou reintervenções. Durante o período de tratamento medicamentoso máximo, não se observou diferenças em cintilografias miocárdicas, testes ergométricos e questionários de qualidade de vida, ainda, houve tendência a piora das classes NYHA (P=0,05) e CCS (P=0,05). Três meses após intervenção, observou-se melhora dos escores cintilográficos SSS (18,38±7,51 vs. 15,31±7,29, P=0,003) e SRS (11,92±7,49 vs. 8,53±6,68, P=0,002), porém não na proporção da extensão da área de miocárdio isquêmico (23,38±13,12 por cento vs. 20,08±13,88 por cento, P=0,1). Houve tendência a melhora dos METs nas ergometrias (7,66±4,47 vs. 10,29±4,36, P=0,08), melhora do escore de qualidade de vida (48,23±18,35 vs. 30,15±20,13; P=0,02) e das classes NYHA (3,15±0,38 vs. 1,77±0,83, P=0,001) e CCS (3,08±0,64 vs. 1,77±0,83, P=0,001), no mesmo período. CONCLUSÕES: A terapia demonstrou-se segura e viável nesta série de pacientes. Os resultados iniciais tendem a demonstrar melhora na gravidade da angina e redução da intensidade da isquemia miocárdica.

OBJECTIVE: Safety, feasibility and early myocardial angiogenic effects evaluation of transthoracic intramyocardial phVEGF165 administration for refractory angina in no option patients. METHODS: Cohort study, in which 13 patients with refractory angina under optimized clinical treatment where included, after cineangiograms had been evaluated and found unfeasible by surgeon and interventional cardiologist. Intramyocardial injections of 5mL solution containing plasmidial VEGF165 where done over the ischemic area of myocardium identified by previous SPECT/Sestamibi scan. Evaluations included a SPECT scan, stress test, Minnesotta QOL questionnaire and NYHA functional class and CCS angina class determinations. RESULTS: There were no deaths or new interventions during the study period. There were no significant variations in SPECT scans, QOL scores and stress tests results during medical treatment in the included patients. After the 3rd post operative month, there was improvement in SPECT segmental scores, SSS (18.38±7.51 vs. 15.31±7.29, P=0.003) and SRS (11.92±7.49 vs. 8.53±6.68, P=0.002). The ischemic area extension, however, had non-significant variation (23.38±13.12 percent vs. 20.08±13.88 percent, P=0.1). Stress tests METs varied from 7.66±4.47 pre to 10.29±4.36 METs post-op (P=0.08). QOL score improved from 48.23±18.35 pre to 30.15±20.13 post-op points (P=0.02). NYHA class was 3.15±0.38 pre vs. 1.77±0.83 post-op (P=0.001) and angina CCS class, 3.08±0.64 vs. 1.77±0.83 (P=0.001). CONCLUSIONS: Intramyocardial VEGF165 therapy for refractory angina, in this small trial of no option patients, resulted feasible and safe. Early clinical and scintilographic data showed improvements in symptoms and myocardial perfusion, with regression of ischemia severity in treated areas.

Long-term effects for acute phase myocardial infarct VEGF165 gene transfer cardiac extracellular matrix remodeling.

BACKGROUND: Cardiac remodeling is ultimately regulated by components of the extracellular matrix (ECM). We investigated the important role that growth factors play in the regulation of ECM remodeling that occurs as a consequence of myocardium damage. METHODS AND RESULTS: Rats were submitted to the ligation of the left anterior coronary artery and pcDNA3-vascular endothelial growth factor (VEGF)(165) was immediately injected intramyocardially in the treated group. The animals were divided into large size myocardium infarction (LMI) and small size myocardium infarction, with or without gene transfer. The plasmid-containing DNA encoding VEGF(165) was injected into the cardiac muscle and its effect was observed on the ECM components. Glycosaminoglycans were identified and quantified by agarose gel based electrophoresis and ELISA as well as immunocytochemistry to examine specific cathepsin B, heparanase, and syndecan-4 changes. The amounts of hyaluronic acid (HA; p < 0.005), DS, chondroitin sulfate, and heparan sulfate (p < 0.001) were significantly increased in the LMI treated group in comparison to the other groups, which correlates with the decrease in the expression of heparanase. A decrease in the molecular mass of HA was found in the scar tissue of treated group. CONCLUSIONS: The data obtained strongly support the idea that changes in the ECM and its components are important determinants of cardiac remodeling after myocardium infarct and may be essential for inflammatory response and attempt to stabilize the damage and provide a compensatory mechanisms to maintain cardiac output since the ECM components analyzed are involved with angiogenesis, cell proliferation and differentiation.

Efecto del factor de crecimiento endotelio vascular (VEGF) sobre perforaciones timpánicas en ratas Long-Evans / Effect of vascular endothelial growth factor (VEGF) on tympanic perforations in Long-Evans rats

Introducción: La anglogenesis es el desarrollo de nuevos vasos sanguíneos desde una red vascular existente, contempla una secuencia de eventos complejos y es fundamental en el proceso reparativo. Existen múltiples factores estimulantes de la angiogénesls, entre ellos se encuentran factores de crecimiento como el VEGF (factor de crecimiento endotelio vascular). Debido a su rol reparativo se han utilizado factores proanglogénicos para reparar perforaciones timpánicas. Objetivo: Estudiar el efecto del VEGF sobre perforaciones timpánicas de ratas Long-Evans. Material y método: Se usan 15 ratas adultas, se realizan perforaciones timpánicas bilaterales, se instilan al azar las perforaciones con solución fisiológica y VEGF, se realiza visualización microscópica de los tímpanos a los días 9,15 y 21 posperforación. Las ratas son sacrificadas el día 21 y se realiza estudio histológico del grosor timpánico. Resultados: No se aprecia un efecto inductivo del VEGF sobre el cierre de las perforaciones timpánicas, se produce un aumento en el grosor timpánico de las ratas tratadas con VEGF.

Direct injection of vascular endothelial growth factor into the ovary of mice promotes follicular development.

OBJECTIVE: To investigate the effects of an ovarian injection of vascular endothelial growth factor (VEGF) on antral follicle development, neoangiogenesis, and apoptosis. DESIGN: Controlled laboratory study. SETTING: University-affiliated fertility center. ANIMAL(S): Balb/c female mice (n = 32) were studied. INTERVENTION(S): Mice were divided into four groups: control group (C) n = 6, no treatment; hyperstimulated group (HS), n = 8, ovaries were stimulated with 7.5 IU pregnant mare serum gonadotropin (PMSG) and 10 IU of hCG; VEGF group (V), n = 8, injected with 0.1 mL of VEGF (0.2 microg) in each ovary; V+HS, n = 8 injected with VEGF and 2 weeks later hyperstimulated. MAIN OUTCOME MEASURE(S): Number of antral and luteinized follicles, number of vessels, and percentage of Bcl-2-positive cells. RESULT(S): The number of antral follicles with VEGF was higher than in the C and HS groups (16.0 +/- 2.5 vs. 6.0 +/- 0.9 and 11.3 +/- 0.6, respectively, p<0.005). All treatments significantly increased the number of vessels (C: 5.0 +/- 0.5 vs. V: 20.0 +/- 4.8, p<0.005 and V+HS: 22.2 +/- 1.2, p<0.01), as well as increased Bcl-2-positive cells compared to controls (C: 0; V: 11.8 +/- 3.5, p<0.005; V+HS: 12.5 +/- 3.7, p<0.005). CONCLUSION(S): Our findings demonstrated that a direct injection of VEGF into the mouse ovary results in the development of an enhanced vascular network promoting follicular development and diminishing apoptosis.

Arteriogenesis induced by intramyocardial vascular endothelial growth factor 165 gene transfer in chronically ischemic pigs.

Exogenous vascular endothelial growth factor (VEGF) improves tissue perfusion in large animals and humans with chronic myocardial ischemia. Because tissue perfusion is mainly dependent on the arteriolar tree, we hypothesized that the neovascularizing effect of VEGF should include arteriogenesis, an effect not as yet described in large mammalian models of myocardial ischemia. In the present study we investigated the effect of intramyocardial plasmid-mediated human VEGF(165) gene transfer (pVEGF(165)) on the proliferation of vessels with smooth muscle in a pig model of myocardial ischemia. In addition, we assessed the effect of treatment on capillary growth, myocardial perfusion, myocardial function and collateralization. Three weeks after positioning of an Ameroid constrictor (Research Instruments SW, Escondido, CA) in the left circumflex artery, pigs underwent basal perfusion (single-photon emission computed tomography [SPECT] with (99m)Tc-sestamibi) and regional function (echocardiography) studies at rest and under dobutamine stress, and were then randomly assigned to receive transepicardial injection of pVEGF(165) 3.8 mg (n = 8) or placebo (empty plasmid, n = 8). All experimental steps and data analysis were done in a blinded fashion. Five weeks later, pVEGF(165)-treated pigs showed a significantly higher density of small (8-50 microm in diameter) vessels with smooth muscle, higher density of capillaries, and improved myocardial perfusion. These results indicate an arteriogenic effect of VEGF in a large mammalian model of myocardial ischemia and encourage the use of VEGF to promote arteriolar growth in patients with severe coronary artery disease.