DEFINING "STRONG" VERSUS "WEAK" RESPONSE TO ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR TREATMENT FOR CENTER-INVOLVED DIABETIC MACULAR EDEMA.

BACKGROUND/PURPOSE: To define "strong" versus "weak" antivascular endothelial growth factor (anti-VEGF) treatment response in eyes with center-involved diabetic macular edema (CI-DME). METHODS: Exploratory analyses of three DRCR Retina Network randomized trials of eyes with CI-DME treated with aflibercept, bevacizumab, or ranibizumab. Thresholds of 5-, 10-, and 15-letter gain defined strong visual acuity (VA) response when baseline VA was 20/25-20/32, 20/40-20/63, or 20/80-20/320, respectively. Thresholds of 50, 100, or 200- µ m reduction defined strong anatomical response when baseline central subfield thickness (CST) was <75, ≥75 to <175, or ≥175- µ m above standard thresholds. Additional thresholds from regression equations were calculated. RESULTS: At 24 weeks, outcomes for strong response were achieved by 476 of 958 eyes (50%) for VA and 505 eyes (53%) for CST. At 104 weeks among the 32% of eyes with strong VA and CST response at 24 weeks, 195 of 281 (69%) maintained strong VA and CST response, whereas 20 (7%) had neither strong VA nor strong CST response. Outcomes rates were similar across protocols and when defined using regression equations. CONCLUSION: These phenotypes are suitable for efforts to identify predictive biomarkers for response to anti-VEGF therapy for DME and might facilitate comparison of treatment response among diverse cohorts with DME.

RISK OF INTRAOCULAR INFLAMMATION AFTER INJECTION OF ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR AGENTS: A Meta-analysis.

PURPOSE: This meta-analysis investigates the incidence of intraocular inflammation (IOI) after intravitreal antivascular endothelial growth factor injections in neovascular age-related macular degeneration. METHODS: A systematic search was performed on Ovid MEDLINE, Embase, and Cochrane Central from January 2005 to April 2021. Randomized controlled trials comparing IOI after intravitreal bevacizumab, ranibizumab, brolucizumab, or aflibercept in neovascular age-related macular degeneration were included. Primary outcomes were sight-threatening IOI, final best-corrected visual acuity, and change in best-corrected visual acuity from baseline. Secondary outcomes included the incidence of other IOI events. Meta-analysis was performed using a random-effects model. RESULTS: Overall, 11,460 unique studies were screened, of which 14 randomized controlled trials and 6,759 eyes at baseline were included. There was no difference between agents for the risk of endophthalmitis and retinal vascular occlusion. Compared with aflibercept, brolucizumab had a higher incidence of generalized IOI (risk ratio = 6.24, 95% confidence interval = [1.40-27.90]) and vitreous haze/floaters (risk ratio = 1.64, 95% confidence interval = [1.00-2.67]). There were no significant differences between comparators for other secondary end points. CONCLUSION: There was no difference in the risk of severe sight-threatening IOI outcomes between intravitreal antivascular endothelial growth factor agents. There was a significantly higher risk of generalized IOI after brolucizumab relative to aflibercept. Our results alongside other recent safety findings suggest the need for further investigation in the risk-benefit profile of brolucizumab for the treatment of neovascular age-related macular degeneration.

Association of Systemic or Intravitreal Antivascular Endothelial Growth Factor (Anti-VEGF) and Impaired Wound Healing in Pediatric Patients: Collagen to the Rescue.

BACKGROUND: Bevacizumab is a humanized monoclonal antibody to vascular endothelial growth factor (VEGF) that has been used as a systemic chemotherapy treatment of various malignancies in adults since 2000. It has been used for pediatric patients over the last decade. In addition, bevacizumab is used for neonatal intravitreal administration for retinopathy of prematurity, a major complication of preterm birth, characterized by incomplete and abnormal vascularization of the retina that can lead to retinal detachment and blindness without treatment. CASES: The objective of this multiple case series is to report impaired wound healing seen in 3 adolescents and 1 premature neonate receiving bevacizumab and to propose collagen-based dermal template as a choice for the management of such wounds. The 3 adolescents were undergoing treatment of malignancies and developed wound healing complication within weeks of receiving anti-VEGF. The premature neonate experienced an extravasation and had a slow wound healing trajectory after receiving intravitreal administration of bevacizumab for retinopathy of prematurity. All wounds achieved closure following topical treatment with a collagen dermal template. CONCLUSION: Use of bevacizumab is increasing in the pediatric population. Clinicians should be aware of compromised wound healing and higher likelihood of wound dehiscence after bevacizumab administration. We recommend waiting for at least 4 to 6 weeks between anti-VEGF administration (either systemic or vitreous) and elective surgical procedures, consistent with adult literature recommendations. If patient has an existing wound, we assert that bevacizumab should not be administered until that wound is healed. If wound healing is stalled, we recommend dermal template as a safe and effective accelerator of wound healing.

Características clínicas, manejo y resultados de los pacientes con endoftalmitis estéril asociados con la inyección intravítrea de factores de crecimiento endotelial antivascular / Clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal injection of antivascular endothelial growth factor

OBJETIVO: Analizar las características clínicas, el manejo y los resultados de los pacientes con endoftalmitis estéril asociada con el factor de crecimiento endotelial antivascular intravítreo. MÉTODOS: Serie de casos de observación retrospectiva de pacientes con endoftalmitis estéril después de inyecciones intravítreas anti-VEGF. Se han revisado los datos clínicos de pacientes tratados con anti-VEGF intravítreos durante un año. Se analizan los que han presentado un episodio de endoftalmitis estéril y se estudia su causalidad y manejo. RESULTADOS: Siete pacientes tuvieron un inicio de endoftalmitis estéril en los 4días posteriores a la inyección intravítrea (aflibercept n = 5 y ranibizumab n = 2). Estos pacientes tienen alguna condición neovascular activa: degeneración macular relacionada con la edad (n = 4), neovascularización coroidea miope (n = 1) o edema macular: edema macular diabético (n = 1), oclusión de la vena retiniana ramificada (n = 1). Los signos y síntomas compartidos incluyeron pérdida de visión indolora, células en cámara anterior o vítrea y falta de hipopión. En todos los pacientes, la agudeza visual volvió a estar dentro de una línea de agudeza basal. CONCLUSIÓN: Diferenciar casos de endoftalmitis estéril de infecciosa puede ser un desafío. Es crucial diferenciar ambas entidades, ya que un buen diagnóstico determina el pronóstico visual. Debemos ser conscientes de una inflamación mínima después de repetidas inyecciones intravítreas para establecer el tratamiento adecuado

PURPOSE: Analyze clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal antivascular endothelial growth factor. METHODS: Observational retrospective case series of patients with sterile endophthalmitis following anti-VEGF intravitreal injections. Clinical data of patients treated with intravitreal anti-VEGFs during one year have been revised. Those who have presented an episode of sterile endophthalmitis are analyzed and their causality and management are studied. RESULTS: Seven patients have had a sterile endophthalmitis onset within 4days after intravitreal injection (aflibercept n = 5 and ranibizumab n = 2). These patients have some active neovascular condition: age related macular degeneration (n = 4), myopic choroidal neovascularization (n = 1) or macular edema: diabetic macular edema (n = 1), branch retinal vein occlusion (n = 1). Shared signs and symptoms included painless vision loss, anterior chamber and vitreous cell and lack of hypopyon. In all patients, visual acuity returned to within one line of baseline acuity. CONCLUSIÓN: Differentiating cases of sterile from infectious endophthalmitis may be challenging. It is crucial to differentiate both entities as a good diagnosis determines the visual prognosis. We should be aware of minimal inflammation after repeated intravitreal injections in order to establish the adequate treatment

Foveal microvasculature, refractive errors, optical biometry and their correlations in school-aged children with retinopathy of prematurity after intravitreal antivascular endothelial growth factors or laser photocoagulation.

AIMS: To compare the differences and to assess the correlations regarding to foveal microvasculature, refractive errors and optical biometry in children with history of type 1 retinopathy of prematurity (ROP) treated with either laser photocoagulation or intravitreal injection of antivascular endothelial growth factors (anti-VEGF). METHODS: This is a retrospective and comparative case series. Measurements of fovea microvasculature included the retinal thickness and subfoveal choroid thickness, the size of fovea avascular zone (FAZ), the fovea, parafovea and perifoveal vessel density (VD). Measurements of refractive errors and optical biometry included spherical equivalent, astigmatism, cornea curvature, anterior chamber depth (ACD), lens thickness and axial length (AXL). RESULTS: A total 47 eyes in 25 children were studied (22 laser-treated eyes from 12 children and 25 anti-VEGF treated eyes from 13 children). Laser-treated eyes had significantly smaller FAZ (p=0.004), higher fovea VD, lower parafoveal VD (p=0.02 and 0.01 in superficial capillary plexus; p=0.05 and 0.01 in deep capillary plexus), thicker inner retinal thickness (p=0.002). Laser-treated eyes had significantly higher degree of myopia (p=0.01). Regarding to optical biometry, laser-treated eyes had significant steeper cornea curvature, shallower ACD and thicker lens (p=0.01, 0.01 and 0.02, respectively) but no differences in AXL was noted (p=0.58). Significant correlations presented between inner retina thickness and FAZ to anterior segment variables. CONCLUSION: In school-aged children with history of type 1 ROP, despite similar visual acuity outcome, those who underwent anti-VEGF injection had favourable developmental outcomes compared with laser photocoagulation. Significant correlations exist between fovea microvasculature and optical biometric components.

Inflammatory stress and altered angiogenesis evoked by very high-fat diets in mouse liver / Las dietas ricas en grasa estimulan procesos inflamatorios y angiogénicos en hígado de ratón

Background: Non-alcoholic fatty liver disease (NAFLD), a condition that leads to fibrosis, is caused by intake of very high-fat diets (HFDs). However, while the negative impact on the liver of these diets has been an issue of interest, systematic research on the effect of HFDs are lacking. Objective: To characterize the overall impact of HFDs on both molecular and morphological signs of liver remodeling. Methods: A study was conducted on male C57BL/6J mice to assess the effect of 4- and 8-week HFDs (60% kcal from fat) on (I) liver steatosis and fibrosis, and (II) expression of factors involved in inflammation and angiogenesis. Results: After an 8-week HFD, vascular endothelial growth factor type-2 receptor (VEGF-R2) and fatty acid translocase/trombospondin-1 receptor (CD36) were overexpressed in liver tissue of mice given HFDs. These changes suggest impaired liver angiogenesis and occurred together with (I) increased GPR78-BiP and EIF2alpha phosphorylation, suggesting endoplasmic reticulum stress, (II) induction of Col1a1 gene expression, a marker of fibrosis, and (III) increased CD31 immunolabeling, consistent with active angiogenesis and fibrosis. Conclusion: Our data show that very HFDs promote a rapid inflammatory response, as well as deregulation of angiogenesis, both consistent with development of liver fibrosis

Antecedentes: El hígado graso no alcohólico (HGNA) es una enfermedad hepática que ocasiona fibrosis y se genera por la ingesta de dietas ricas en grasa. Aunque los efectos nocivos de este tipo de dietas son de gran interés, no son muy abundantes los estudios sistemáticos sobre las consecuencias que su consumo puede tener en el hígado. Objetivo: Evaluar los efectos de una dieta rica en grasa sobre el remodelado hepático, tanto a nivel morfológico como molecular. Métodos: Se utilizaron ratones macho C57BL/6J tratados durante 4/8 semanas con una dieta que contenía un 60% de las kilocalorías procedentes de grasa sobre: 1) la aparición de esteatosis y/o fibrosis hepática y 2) la expresión de factores implicados en procesos de inflamación y angiogénesis. Resultados: Tras 8 semanas de dieta se observó un incremento en el receptor del factor de crecimiento vascular endotelial tipo 2 (R2-FCVE) y en la translocasa de ácidos grasos (CD36). Estos cambios, que sugieren que los procesos angiogénicos del hígado están alterados, fueron simultáneos a: 1) un aumento del GPR78-BiP y de la fosforilación de EIF2alpha, marcadores de estrés del retículo endoplásmico, 2) la inducción en la expresión del gen de colágeno Col1a1, indicador de fibrosis y 3) un incremento de células inmunofluorescentes para CD31 compatible con procesos de angiogénesis y de fibrosis. Conclusiones: Nuestros resultados muestran que las dietas con alto contenido en grasa inducen la rápida activación de respuestas inflamatorias, así como alteraciones en la angiogénesis, siendo ambos procesos compatibles con el desarrollo de fibrosis hepática

Nitric oxide mediates bleomycin-induced angiogenesis and pulmonary fibrosis via regulation of VEGF.

Pulmonary fibrosis is a progressive lung disease hallmarked by increased fibroblast proliferation, amplified levels of extracellular matrix deposition and increased angiogenesis. Although dysregulation of angiogenic mediators has been implicated in pulmonary fibrosis, the specific rate-limiting angiogenic markers involved and their role in the progression of pulmonary fibrosis remains unclear. We demonstrate that bleomycin treatment induces angiogenesis, and inhibition of the central angiogenic mediator VEGF using anti-VEGF antibody CBO-P11 significantly attenuates bleomycin-induced pulmonary fibrosis in vivo. Bleomycin-induced nitric oxide (NO) was observed to be the key upstream regulator of VEGF via the PI3k/Akt pathway. VEGF regulated other important angiogenic proteins including PAI-1 and IL-8 in response to bleomycin exposure. Inhibition of NO and VEGF activity significantly mitigated bleomycin-induced angiogenic and fibrogenic responses. NO and VEGF are key mediators of bleomycin-induced pulmonary fibrosis, and could serve as important targets against this debilitating disease. Overall, our data suggests an important role for angiogenic mediators in the pathogenesis of bleomycin-induced pulmonary fibrosis.

Multifunctional polyurethane-urea nanoparticles to target and arrest inflamed vascular environment: a potential tool for cancer therapy and diagnosis.

Activation of inflammatory pathways in endothelial cells contributes to tumour growth and progression in multiple human cancers. Cellular adhesion molecules are involved in leukocyte recruitment to the vascular inflammatory environment where it plays a critical role in angiogenesis, suppression of apoptosis, proliferation, invasion and metastasis. We describe here the development of streptavidin-coated polyurethane-urea nanoparticles as multifunctional nanocarriers for fluorescence imaging or targeting of the tumour environment to identify and arrest the vascular network irrigating the tumour tissue. The design of these multifunctional nanoparticles involves incorporating streptavidin to the nanoparticle polymeric matrix. The obtained nanoparticles are spherical and exhibit an average diameter of 70-74 nm. Streptavidin-coated nanoparticles spontaneously bind biotinylated antibodies against VCAM-1 and ICAM-1 which in vitro and in vivo specifically attached to inflamed endothelial cells. Indeed the incorporation of CBO-P11 (a specific inhibitor of the vascular endothelial growth factor proangiogenic and proinflammatory pathway) to these nanoparticles allows a targeted pharmacological effect thereby decreasing the proliferation only in inflamed endothelial cells. The multiple functionalisation strategy described here could be exploited for tumour diagnostics or targeted drug delivery to tumour vasculature with a good safety profile and an attractive array of possibilities for biomedical applications.

Recombinant IGFBP-3 inhibits allergic lung inflammation, VEGF production, and vascular leak in a mouse model of asthma.

BACKGROUND: Vascular endothelial growth factor (VEGF) plays a pro-inflammatory mediator as well as a vascular permeability factor in bronchial asthma. Insulin-like growth factor (IGF)-I is also involved in the inflammatory process associated with bronchial asthma and stimulates VEGF expression. The IGF-binding proteins (IGFBPs), especially IGFBP-3, display distinctive properties and can interfere with various biological processes. METHODS: In this study, an ovalbumin (OVA)-induced murine model of allergic airway disease was used to investigate which mechanism is implicated in the preventive and therapeutic actions of IGFBP-3 administered exogenously on allergen-induced bronchial inflammation and airway hyper-responsiveness, in particular focusing on the regulation of VEGF expression. RESULTS: Administration of recombinant human IGFBP-3 to OVA-inhaled mice substantially attenuated the increases in hypoxia-inducible factor (HIF)-α activity, IGF-I production, and VEGF protein levels in the lung. In addition, the blockade of IGF-I action decreased the OVA-induced VEGF expression, airway inflammation, and bronchial hyper-responsiveness. The administration of recombinant human IGFBP-3 or CBO-P11 also reduced significantly increases in inflammatory cells, airway hyper-responsiveness, levels of IL-4, IL-5, IL-13, and vascular permeability in the lung of OVA-inhaled mice. Moreover, when recombinant human IGFBP-3 was administered after the completion of OVA inhalation, these therapeutic effects of IGFBP-3 were also observed. CONCLUSIONS: These results indicate that IGFBP-3 administered exogenously may attenuate antigen-induced airway inflammation and hyper-responsiveness through the modulation of vascular leakage and VEGF expression mediated by HIF-1α/HIF-2α signaling as well as IGF-I action in allergic airway disease of mice.

Recruitment of a prostaglandin E receptor subtype, EP3-expressing bone marrow cells is crucial in wound-induced angiogenesis.

E-type prostaglandins have been reported to be proangiogenic in vivo. Thus, we examined prostaglandin receptor signaling relevant to wound-induced angiogenesis. Full-thickness skin wounds were created on the backs of mice, and angiogenesis in wound granulation tissues was estimated. Wound closure and re-epithelization in EP3 receptor knockout mice (EP3-/-) were significantly delayed compared with their wild-type (WT) mice, whereas those in EP1-/-, EP2-/-, and EP4-/- were not delayed. Wound-induced angiogenesis estimated with CD31 immunohistochemistry in EP3-/- mice was significantly inhibited compared with that in WT mice. Immunoreactive vascular endothelial growth factor (VEGF) in wound granulation tissues in EP3-/- mice was markedly less than that in WT mice. Wound closure in WT mice was delayed significantly by VEGF neutralizing antibody compared with control IgG. Wound-induced angiogenesis and wound closure were significantly suppressed in EP3-/- bone marrow transplantation mice compared with those in WT bone marrow transplantation mice. These were accompanied with the reductions in accumulation of VEGF-expressing cells in wound granulation tissues and in mobilization of VEGF receptor 1-expressing leukocytes in peripheral circulation. These results indicate that the recruitment of EP3-expressing cells to wound granulation tissues is critical for surgical wound healing and angiogenesis via up-regulation of VEGF.

¿Qué utilidad tiene en la práctica clínica medir la función endotelial? / What is the utility of measuring endothelial function in clinical practice?

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Effects of local administration of vascular endothelial growth factor on properties of the in situ frozen-thawed anterior cruciate ligament in rabbits.

BACKGROUND: In the autogenous tendon for anterior cruciate ligament reconstruction, intrinsic fibroblasts are necrotized immediately after surgery, and repopulation and revascularization occur. Vascular endothelial growth factor is considered to be a potent mediator of angiogenesis. HYPOTHESIS: An application of vascular endothelial growth factor significantly enhances angiogenesis in the in situ frozen anterior cruciate ligament, and the application significantly affects mechanical properties of the in situ frozen anterior cruciate ligament. STUDY DESIGN: Controlled laboratory study. METHODS: Right anterior cruciate ligaments from 66 rabbits underwent the freeze-thaw treatment, and animals were then divided into 3 groups. Group I served as a freeze-thaw but otherwise untreated control. In group II, 0.2 mL phosphate-buffered saline alone was applied. In group III, 30 mug vascular endothelial growth factor was applied. The groups were compared on the basis of histologic revascularization examinations using the Chalkley score, an indicator of the microvessel density, and mechanical evaluations, which included the anterior-posterior translation of the tibia relative to the femur during +/- 10 N of anterior-posterior load and the mechanical properties of the anteromedial bundle of the anterior cruciate ligament. RESULTS: Group III's Chalkley score was significantly greater than that of groups I and II. The tensile strength and the tangent modulus of anterior cruciate ligaments in groups I, II, and III were significantly lower than those of a normal anterior cruciate ligament, although there were no significant differences among groups I, II, and III. CONCLUSION: Vascular endothelial growth factor, as administered in this study, significantly promoted angiogenesis in the devitalized anterior cruciate ligament with in situ freeze-thaw treatment, but it did not affect the mechanical properties of the in situ frozen-thawed anterior cruciate ligament in the rabbit model. CLINICAL RELEVANCE: An application of the recombinant anterior cruciate ligament is a potential future strategy to enhance revascularization of the autograft in anterior cruciate ligament reconstruction.

Topical VEGF enhances healing of thoracic aortic anastomosis for coarctation in a rabbit model.

BACKGROUND: Recurrent stenosis after extended end-to-end anastomosis for aortic coarctation is the primary indication for further interventions in children. Tension because of the extended resection and local arterial wall hypoxia are possible pathogenetic mechanisms. We hypothesized that (1) tension interferes with healing and (2) that vascular endothelial growth factor (VEGF), a hypoxia sensitive angiogenic inducer, may enhance healing of the vascular anastomosis. METHODS AND RESULTS: In a model of coarctation repair, rabbits underwent thoracic aortic end-to-end anastomosis after transection (no-tension; n=15), resection of an aortic ring (tension; n=14) or resection and topical VEGF treatment (0.75 microg VEGF165; tension+VEGF; n=14). Gross and histologic characteristics of the aortic wall were assessed at 1 week, 1 and 2 months. In the tension only group at 1 month, the severity of vascular remodeling was increased with fibrosis and calcification compared with controls. At 2 months, this group also revealed more luminal stenosis (29% versus 19%; P<0.001). Exogenous VEGF resulted in significantly less fibrosis, calcification and chondroid metaplasia at 1 month (P<0.05) and luminal area was only reduced 3% at 2 months (P<0.001 versus tension group). CONCLUSIONS: In a rabbit model of coarctation repair, the addition of tension on the vascular anastomosis resulted in poor healing and luminal stenosis. Topical VEGF maintained luminal integrity by decreasing fibrosis and calcification. These findings suggest that topical VEGF may be a promising new strategy to enhance healing and improve the outcome of vascular anastomoses for coarctation of the aorta.

Regional angiogenesis with vascular endothelial growth factor in peripheral arterial disease: a phase II randomized, double-blind, controlled study of adenoviral delivery of vascular endothelial growth factor 121 in patients with disabling intermittent claudication.

BACKGROUND: "Therapeutic angiogenesis" seeks to improve perfusion by the growth of new blood vessels. The Regional Angiogenesis with Vascular Endothelial growth factor (RAVE) trial is the first major randomized study of adenoviral vascular endothelial growth factor (VEGF) gene transfer for the treatment of peripheral artery disease (PAD). METHODS AND RESULTS: This phase 2, double-blind, placebo-controlled study was designed to test the efficacy and safety of intramuscular delivery of AdVEGF121, a replication-deficient adenovirus encoding the 121-amino-acid isoform of vascular endothelial growth factor, to the lower extremities of subjects with unilateral PAD. In all, 105 subjects with unilateral exercise-limiting intermittent claudication during 2 qualifying treadmill tests, with peak walking time (PWT) between 1 to 10 minutes, were stratified on the basis of diabetic status and randomized to low-dose (4x10(9) PU) AdVEGF121, high-dose (4x10(10) PU) AdVEGF121, or placebo, administered as 20 intramuscular injections to the index leg in a single session. The primary efficacy end point, change in PWT (DeltaPWT) at 12 weeks, did not differ between the placebo (1.8+/-3.2 minutes), low-dose (1.6+/-1.9 minutes), and high-dose (1.5+/-3.1 minutes) groups. Secondary measures, including DeltaPWT, ankle-brachial index, claudication onset time, and quality-of-life measures (SF-36 and Walking Impairment Questionnaire), were also similar among groups at 12 and 26 weeks. AdVEGF121 administration was associated with increased peripheral edema. CONCLUSIONS: A single unilateral intramuscular administration of AdVEGF121 was not associated with improved exercise performance or quality of life in this study. This study does not support local delivery of single-dose VEGF121 as a treatment strategy in patients with unilateral PAD.

Adenoviral-mediated gene transfer of vascular endothelial growth factor in critical limb ischemia: safety results from a phase I trial.

Critical limb ischemia (CLI) is typified by rest pain and/or tissue necrosis secondary to advanced peripheral arterial disease (PAD) and is characterized by diminution in limb perfusion at rest. We tested the safety of an angiogenic strategy with CI-1023 (Ad(GV)VEGF121.10), a replication-deficient adenovirus encoding human vascular endothelial growth factor isoform 121 in patients with CLI as part of a phase I trial. Fifteen subjects >35 years of age with CLI and angiographic disease involving the infra-inguinal vessels underwent intramuscular injection of CI-1023 (4 x 10(8) to 4 x 10(10) particle units, n = 13) or placebo (n = 2). All of the patients tolerated the injection well and there were no serious complications related to the procedure. Transient edema was noted in one patient. A total of 79 adverse events were reported over the course of one year. One death (day 136) and one malignancy (day 332) occurred in the CI-1023 group. CI-1023 appears to be well tolerated and safe for single-dose administration in patients with critical limb ischemia due to PAD. Further studies are needed to determine the efficacy of this form of therapeutic angiogenesis.

Angiogenic effects of injected VEGF165 and sVEGFR-1 (sFLT-1) in a rat flap model.

BACKGROUND: Injections of single-dose vascular endothelial growth factor (VEGF)(165) have been advocated as a therapeutic tool for angiogenesis in ischemic flaps. We challenged this thesis by employing both VEGF(165) and vascular endothelial growth factor receptor-1 (VEGFR-1) (for competitive inhibition of VEGF signal transduction) in different experimental settings of an ischemic rat flap model. MATERIAL AND METHODS: 80 isogenic rats were divided in two groups of 40 animals (groups 1A-1D and 2A-2D). The ischemic target was a 7 x 7-cm epigastric island flap, based on the right inferior epigastric pedicle. Group 1 received flap treatment 1 week prior to flap elevation by test substance injection into its flap panniculus carnosus: 1 ml NaCl 0.9% (1A), 1 ml Dulbecco's modified Eagle's medium (1B), 1.0 microg VEGF(165) (1C), and 10 microg sFLT-1 with 1.0 microg VEGF(165) (1D). sFLT-1 is a soluble receptor for VEGF and is able to prevent VEGF signaling through the cell surface receptor. Group 2 had the same flap treatment at the day of flap elevation. RESULTS: In group 1C we found the most vital flap tissue, without reaching significance. Compared with group 1D, however, significantly more flap tissue maintained vital. In groups 2A-2D, no significant results were found with respect to flap survival. CONCLUSIONS: Local application of single-dose VEGF(165) 1 week prior to ischemia dose not have significant clinical angiogenic effects. In this experimental setting, VEGF(165)-induced angiogenic effects can be significantly inhibited by adding sFLT1 in vivo. A single-dose of VEGF(165) under ischemic conditions causes no significantly better flap survival in this model.

Safety and feasibility of catheter-based local intracoronary vascular endothelial growth factor gene transfer in the prevention of postangioplasty and in-stent restenosis and in the treatment of chronic myocardial ischemia: phase II results of the Kuopio Angiogenesis Trial (KAT).

BACKGROUND: Catheter-based intracoronary vascular endothelial growth factor (VEGF) gene transfer is a potential treatment for coronary heart disease. However, only limited data are available about local VEGF gene transfer given during angioplasty (PTCA) and stenting. METHODS AND RESULTS: Patients with coronary heart disease (n=103; Canadian Cardiovascular Society class II to III; mean age, 58+/-6 years) were recruited in this randomized, placebo-controlled, double-blind phase II study. PTCA was performed with standard methods, followed by gene transfer with a perfusion-infusion catheter. Ninety percent of the patients were given stents; 37 patients received VEGF adenovirus (VEGF-Adv, 2x10(10) pfu), 28 patients received VEGF plasmid liposome (VEGF-P/L; 2000 microg of DNA with 2000 microL of DOTMA:DOPE [1:1 wt/wt]), and 38 control patients received Ringer's lactate. Follow-up time was 6 months. Gene transfer to coronary arteries was feasible and well tolerated. The overall clinical restenosis rate was 6%. In quantitative coronary angiography analysis, the minimal lumen diameter and percent of diameter stenosis did not significantly differ between the study groups. However, myocardial perfusion showed a significant improvement in the VEGF-Adv-treated patients after the 6-month follow-up. Some inflammatory responses were transiently present in the VEGF-Adv group, but no increases were detected in the incidences of serious adverse events in any of the study groups. CONCLUSIONS: Gene transfer with VEGF-Adv or VEGF-P/L during PTCA and stenting shows that (1) intracoronary gene transfer can be performed safely (no major gene transfer-related adverse effects were detected), (2) no differences in clinical restenosis rate or minimal lumen diameter were present after the 6-month follow-up, and (3) a significant increase was detected in myocardial perfusion in the VEGF-Adv-treated patients.

Effects of vascular endothelial growth factor on wound closure rates in the genetically diabetic mouse model.

Impaired wound healing is characteristic of diabetic patients. Potential reasons include poor inflammatory response, granulation tissue formation, and abnormal patterns of cytokine release and response. Vascular endothelial growth factor, abnormally regulated during healing in diabetics, is the major factor stimulating angiogenesis during normal wound healing. We tested our hypothesis that topically applied vascular endothelial growth factor would improve wound closure rates in diabetic animals in a full-thickness wound model in genetically diabetic mice (C57 BL/KsJ db/db). Animals received either 1.0 micro g of vascular endothelial growth factor165 or polyethylene glycol alone topically to wounds daily between days 0 and 4 post-wounding. Wound area was measured at days 0, 5, 10, 15, and 21. Data were analyzed using probit analysis and expressed as length-of-time (LT) to 50, 90, and 95% wound closure. Among untreated animals, nondiabetics had an LT50 of 8.5 days (fiducial limits 8.3-8.7), while diabetics had an LT50 of 15.8 days (15.6-16.1). Vascular endothelial growth factor-treated animals had LT50 values of 7.8 (7.6-8.1) and 11.8 days (11.6-12.0) for nondiabetics and diabetics, respectively, representing a 25% improvement in time to 50% closure in treated diabetics. We conclude that topically applied vascular endothelial growth factor improves time to wound closure in the genetically diabetic mouse model.

Fibrin-based biomaterials to deliver human growth factors.

Fibrin-based biomaterial preparations can be used as provisional growth matrices for cells important in tissue repair during wound healing in vivo. Their efficacy can be enhanced by including bioactive agents that promote specific cellular responses. This study examined the controlled delivery of the angiogenic growth factors bFGF, VEGF(165), and VEGF(121) using biomatrix preparations prepared from Fibrin Sealant product components. The growth factors were added prior to formation of the Fibrin Sealant clots, and the release kinetics of the proteins from the clots measured. The results indicated that the proteins were released from the clots more slowly in the order bFGF << VEGF(165) < VEGF(121). The biologic activity of the growth factors delivered from Fibrin Sealant clots was established by assaying growth stimulation of human microvascular endothelial cells (HMVEC) and angiogenesis in the chicken embryo chorioallantoic membrane (CAM) model of neovascularization. In the latter assay, clots containing bFGF, VEGF(165), or VEGF(121) all displayed angiogenic activity. However, delivery of either bFGF, VEGF(165), or VEGF(121) alone resulted in a significant percentage of clots becoming filled with blood, indicating that the newly developing vessels invading the clots were leaky and immature. In contrast, this hemorrhaging behavior did not occur with delivery of combinations, e.g., (VEGF(165) + VEGF(121)) or (VEGF(165) + bFGF), indicating that the vessels were more mature than those produced in response to single growth factors. Thus, delivering a combination of growth factors constituted an improvement over the delivery of individual growth factors for enhancing neovascularization.