Vascular Endothelial Growth Factor Blocker Research Articles

Production of a biosimilar version of aflibercept to improve VEGF blocker cytotoxicity on endothelial cells

This project aimed to produce a biosimilar version of aflibercept (AFL) and evaluate the effect of the co-treatment of AFL with other vascular endothelial growth factor (VEGF) blocker drugs. For this purpose, the optimized gene was inserted into the pCHO1.0 plasmid and transfected into the CHO-S cell line. The final concentration of biosimilar-AFL for the selected clone was 782 mg/L. Results revealed that the inhibition potential of the biosimilar-AFL on HUVEC cells was significant at 10 and 100 nM concentrations and in a dose-dependent manner. Furthermore, co-treatment of biosimilar-AFL with Everolimus (EVR), Lenvatinib (LEN), and Sorafenib (SOR) could reduce HUVEC cell viability/proliferation, more than when used alone. When LEN and SOR were co-treated with biosimilar-AFL, their cytotoxicity increased 10-fold. The most and least efficient combination was seen when biosimilar-AFL combined with LEN and EVR, respectively. Finally, biosimilar-AFL may improve the efficiency of LEN, EVR, and SOR in reducing the VEGF effect on endothelial cells.

Improvement in visual acuity and retinal phenotype with intravitreal aflibercept (anti-VEGF) in POEMS syndrome with Castleman disease variant

A woman in her thirties with no ophthalmic history presented two days of flashes and floaters. She had reduced right-eye visual acuity, bilateral retinal hemorrhages, and papilledema. She was diagnosed with polyneuropathy, organomegaly, endocrinopathy, myeloma protein, and skin changes (POEMS) syndrome with Castleman disease variant, with elevated systemic levels of vascular endothelial growth factor (VEGF). Three doses of aflibercept (VEGF blocker) were administered to the right eye. The right eye improved from 6/60 to 6/5 after treatment. We suggest that intravitreal VEGF blockade should be considered to preserve vision in patients with POEMS syndrome and high circulating VEGF.

Anti-inflammatory activities of a new VEGF blocker, Conbercept

Background Angiogenesis and inflammation exhibit a mutually reinforcing relationship in many human diseases. Vascular endothelial growth factor (VEGF) is one of the most important proangiogenic mediators. Conbercept is a novel VEGF inhibitor. Method Type II collagen-induced rat rheumatoid arthritis (CIA) model was established to evaluate the anti-chronic inflammation activities of Conbercept. ELISA was used to measure the concentrations of immune factors in the blood of arthritis rats. The xylene-induced ear edema was conducted to evaluate the effect of Conbercept on acute inflammation. Result and discussion Our results showed that Conbercept significantly reduced the paw edema volume and the arthritis index in CIA rats. Furthermore, we found that Conbercept decreased the serum levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in CIA rats. Xylene-induced ear edema is a widely used method to study acute inflammation. Conbercept significantly inhibited xylene-induced ear edema. Conclusion All results indicate that Conbercept exhibits significant inhibition of acute and chronic inflammation.

Anti-angiogenic potential of VEGF blocker dendron loaded on to gellan gum hydrogels for tissue engineering applications.

Damage of non-vascularised tissues such as cartilage and cornea can result in healing processes accompanied by a non-physiological angiogenesis. Peptidic aptamers have recently been reported to block the vascular endothelial growth factor (VEGF). However, the therapeutic applications of these aptamers are limited due to their short half-life in vivo. In this work, an enhanced stability and bioavailability of a known VEGF blocker aptamer sequence (WHLPFKC) was pursued through its tethering of molecular scaffolds based on hyperbranched peptides, the poly(ɛ-lysine) dendrons, bearing three branching generations. The proposed design allowed simultaneous and orderly-spaced exposure of 16 aptamers per dendrimer to the surrounding biological microenvironent, as well as a relatively hydrophobic core based on di-phenylalanine aiming to promote an hydrophobic interaction with the hydrophobic moieties of ionically crosslinked methacrylated gellan gum (iGG-MA) hydrogels. The VEGF blocker dendrons were entrapped in iGG-MA hydrogels, and their capacity to prevent endothelial cell sprouting was assessed qualitatively and quantitatively using 3D in vitro models and the in vivo chick chorioallantoic membrane assay. The data demonstrate that at nanoscale concentrations, the dendronised structures were able to enhance control of the biological actvity of WHLPFKC at the material/tissue interface and hence the anti-angiogenic capacity of iGG-MA hydrogels not only preventing blood vessel invasion, but also inducing their regression at the tissue/iGG-MA interface. The in ovo study confirmed that iGG-MA functionalised with the dendron VEGF blockers do inhibit angiogenesis by controlling both size and ramifications of blood vessels in the proximity of the implanted gel surface. Copyright © 2016 John Wiley & Sons, Ltd.

Combination of the histone deacetylase inhibitor vorinostat with bevacizumab in patients with clear-cell renal cell carcinoma: a multicentre, single-arm phase I/II clinical trial

Background:Class II histone deacetylase (HDAC) inhibitors induce hypoxia-inducible factor-1 and -2α degradation and have antitumour effects in combination with vascular endothelial growth factor (VEGF) inhibitors. In this study, we tested the safety and efficacy of the HDAC inhibitor vorinostat and the VEGF blocker bevacizumab in metastatic clear-cell renal cell carcinoma (ccRCC) patients previously treated with different drugs including sunitinib, sorafenib, axitinib, interleukin-2, interferon, and temsirolimus.Methods:Patients with up to two prior regimens were eligible for treatment, consisting of vorinostat 200 mg orally two times daily × 2 weeks, and bevacizumab 15 mg kg−1 intravenously every 3 weeks. The primary end points were safety and tolerability, and the proportion of patients with 6 months of progression-free survival (PFS). Correlative studies included immunohistochemistry, FDG PET/CT scans, and serum analyses for chemokines and microRNAs.Results:Thirty-six patients were enrolled, with 33 evaluable for toxicity and efficacy. Eighteen patients had 1 prior treatment, 13 patients had 2 prior treatments, and 2 patients were treatment naïve. Two patients experienced grade 4 thrombocytopenia and three patients had grade 3 thromboembolic events during the course of exposure. We observed six objective responses (18%), including one complete response and five partial responses. The proportion of patients with PFS at 6 months was 48%. The median PFS and overall survival were 5.7 months (confidence interval (CI): 4.1–11.0) and 13.9 months (CI: 9.8–20.7), respectively. Correlative studies showed that modulation of specific chemokines and microRNAs were associated with clinical benefit.Conclusions:The combination of vorinostat with bevacizumab as described is relatively well tolerated. Response rate and median PFS suggest clinical activity for this combination strategy in previously treated ccRCC.

Dual blockade of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) exhibits potent anti-angiogenic effects

Both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF or FGF-2) are potent pro-angiogenic factors and play a critical role in cancer development and progression. Clinical anti-VEGF therapy trials had a major challenge due to upregulated expression of other pro-angiogenic factor, like FGF-2. This study developed a novel chimeric decoy receptor VF-Trap fusion protein to simultaneously block activity of both VEGF and FGF pathways in order to achieve an additive or synergistic anti-tumor effect. Our in vitro data showed that VF-Trap potently blocked proliferation and migration of both VEGF- and FGF-2-induced vascular endothelial cells. In animal models, treatment of xenograft tumors with VF-Trap resulted in significant inhibition of tumor growth compared to blockage of the single molecule, like VEGF or FGF blocker. In addition, VF-Trap was also more potent in inhibition of ocular angiogenesis in a mouse oxygen-induced retinopathy (OIR) model. These data demonstrated the potent anti-angiogenic effects of this novel VF-Trap fusion protein on blockage of VEGF and FGF-2 activity in vitro and in animal models. Further study will assess its effects in clinic as a therapeutic agent for angiogenesis-related disorders, such as cancer and ocular vascular diseases.

Novel vascular endothelial growth factor blocker improves cellular viability and reduces hypobaric hypoxia-induced vascular leakage and oedema in rat brain.

Vascular endothelial growth factor (VEGF) is an important cerebral angiogenic and permeability factor under hypoxia. There is a need to find effective molecules that may ameliorate hypoxia-induced cerebral oedema. In silico identification of novel candidate molecules that block VEGF-A site were identified and validated with a Ramachandran plot. The active site residues of VEGF-A were detected by Pocketfinder, CASTp, and DogSiteScorer. Based on in silico data, three VEGF-A blocker (VAB) candidate molecules (VAB1, VAB2, and VAB3) were checked for improvement in cellular viability and regulation of VEGF levels in N2a cells under hypoxia (0.5% O2 ). Additionally, the best candidate molecule's efficacy was assessed in male Sprague-Dawley rats for its ameliorative effect on cerebral oedema and vascular leakage under hypobaric hypoxia 7260 m. All experimental results were compared with the commercially available VEGF blocker sunitinib. Vascular endothelial growth factor-A blocker 1 was found most effective in increasing cellular viability and maintaining normal VEGF levels under hypoxia (0.5% oxygen) in N2a cells. Vascular endothelial growth factor-A blocker 1 effectively restored VEGF levels, decreased cerebral oedema, and reduced vascular leakage under hypobaric hypoxia when compared to sunitinib-treated rats. Vascular endothelial growth factor-A blocker 1 may be a promising candidate molecule for ameliorating hypobaric hypoxia-induced vasogenic oedema by regulating VEGF levels.

Dll4 blockade potentiates the anti-tumor effects of VEGF inhibition in renal cell carcinoma patient-derived xenografts.

BackgroundThe Notch ligand Delta-like 4 (Dll4) is highly expressed in vascular endothelium and has been shown to play a pivotal role in regulating tumor angiogenesis. Blockade of the Dll4-Notch pathway in preclinical cancer models has been associated with non-productive angiogenesis and reduced tumor growth. Given the cross-talk between the vascular endothelial growth factor (VEGF) and Delta-Notch pathways in tumor angiogenesis, we examined the activity of a function-blocking Dll4 antibody, REGN1035, alone and in combination with anti-VEGF therapy in renal cell carcinoma (RCC).Methods and ResultsSevere combined immunodeficiency (SCID) mice bearing patient-derived clear cell RCC xenografts were treated with REGN1035 and in combination with the multi-targeted tyrosine kinase inhibitor sunitinib or the VEGF blocker ziv-aflibercept. Immunohistochemical and immunofluorescent analyses were carried out, as well as magnetic resonance imaging (MRI) examinations pre and 24 hours and 2 weeks post treatment. Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36–62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38–54%) and ziv-aflibercept (46%). Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72–80% growth inhibition), including some tumor regression. Magnetic resonance imaging showed a marked decrease in tumor perfusion in all treatment groups. Interestingly, anti-tumor efficacy of the combination of REGN1035 and ziv-aflibercept was also observed in a sunitinib resistant ccRCC model.ConclusionsOverall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

Synergistic effects of curcumin and bevacizumab on cell signaling pathways in hepatocellular carcinoma.

The aim of the present study was to explore the effects of curcumin in combination with bevacizumab on the vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)/K-ras pathway in hepatocellular carcinoma. A total of 30 Sprague Dawley (SD) rats were randomly divided into five groups: Control, model, curcumin, VEGF blocker, and curcumin + VEGF blocker groups. The mRNA levels of VEGF and VEGFR in all groups were subsequently measured by quantitative reverse transcriptase-polymerase chain reaction and the protein expression of K-ras was detected by western blot analysis. Compared with the control group, the mRNA levels of VEGF and VEGFR were revealed to be significantly increased in the model, curcumin and VEGF blocker groups. The VEGF mRNA levels in the curcumin, VEGF blocker and curcumin + VEGF blocker groups were all decreased when compared with the model group. In addition, the VEGF mRNA levels in the curcumin + VEGF blocker group were significantly lower compared with the curcumin group (P<0.05). The VEGF mRNA levels in the curcumin, VEGF blocker and curcumin + VEGF blocker groups were decreased when compared with the model group (P=0.0001). No significant differences in VEGF mRNA levels were identified between the VEGF blocker and curcumin groups (P=0.863), whereas the VEGF mRNA levels in the curcumin + VEGF blocker group were significantly lower than that of the curcumin group (P=0.025). Curcumin and the VEGF blocker are each capable of inhibiting hepatocellular carcinoma progression by regulating the VEGF/VEGFR/K-ras pathway. The combination of the two compounds has a synergistic effect on the inhibition of the effects of the VEGF signaling pathways in hepatocellular carcinoma progression.

Novel dual endothelin receptor antagonist macitentan reverses severe pulmonary arterial hypertension in rats.

The efficacy of endothelin (ET) receptor antagonist bosentan in patients with severe pulmonary arterial hypertension (PAH) remains limited, partly because its higher doses for potential blockade of ET receptors have never been tested due to liver dysfunction. We hypothesized that rigorous blockade of ET receptors using the novel dual ET receptor antagonist macitentan would be effective in treating severe PAH without major side effects in a preclinical model appropriately representing the human disorder. In normal rats, 30 mg·kg·d of macitentan completely abolished big ET-1-induced increases in right ventricle (RV) systolic pressure. Adult male rats were injected with SU5416, a vascular endothelial growth factor blocker, and exposed to hypoxia for 3 weeks and then to normoxia for an additional 5 weeks (total 8 weeks). In intrapulmonary arterial rings isolated from rats with severe PAH, macitentan concentration dependently inhibited ET-1-induced contraction. Long-term treatment with macitentan (30 mg·kg·d, from week 3 to 8) reversed the high RV systolic pressure with preserved cardiac output. Development of RV hypertrophy, luminal occlusive lesions and medial wall thickening were also significantly improved without increasing serum levels of liver enzymes by macitentan. In conclusion, efficacious blockade of ET receptors with macitentan would reverse severe PAH without major adverse effects.

Ziv-aflibercept: A novel angiogenesis inhibitor for the treatment of metastatic colorectal cancer

The pharmacology, pharmacokinetics, clinical efficacy, safety, and administration of ziv-aflibercept in combination therapy for metastatic colorectal cancer (mCRC) are reviewed. Ziv-aflibercept (Zaltrap, Regeneron Pharmaceuticals and sanofi-aventis) is a novel recombinant fusion protein that targets the angiogenesis signaling pathway of tumor cells by blocking vascular endothelial growth factor (VEGF) receptors that play a key role in tumor growth and metastasis; it is a more potent VEGF blocker than bevacizumab. Ziv-aflibercept is approved by the Food and Drug Administration for use in combination with fluorouracil, irinotecan, and leucovorin (the FOLFIRI regimen) for second-line treatment of patients with mCRC who have disease progression during first-line oxaliplatin-based chemotherapy. A Phase III trial demonstrated that relative to FOLFIRI therapy alone, the use of ziv-aflibercept was associated with significantly improved patient response, overall survival, and progression-free survival in patients with good performance status at baseline, including some who had received prior bevacizumab therapy. The most common grade 3 or 4 adverse effects associated with ziv-aflibercept use in clinical studies were neutropenia, hypertension, and diarrhea; the U.S. product labeling warns of potential hemorrhage and other treatment-related risks. Current clinical data are insufficient to directly compare ziv-aflibercept and bevacizumab when used with standard combination chemotherapy as first- or second-line regimens for mCRC. The role of ziv-aflibercept is currently limited to the second-line setting in combination with irinotecan-based regimens in mCRC patients who have not received irinotecan previously. The role of ziv-aflibercept in chemotherapy for other tumor types is yet to be determined.

Can We Identify Predictive Biomarkers for Antiangiogenic Therapy of Cancer Using Mathematical Modeling?

Can We Identify Predictive Biomarkers for Antiangiogenic Therapy of Cancer Using Mathematical Modeling?

FP3: A Novel VEGF Blocker with Anti-Angiogenic and Anti-Tumor Effects

Vascular endothelial growth fac-tor (VEGF) serves as a logical target for antiangiogenic cancer therapy. This study is to investigate the inhibitory effects of FP3, a novel VEGF blocker, on angiogenesis in vitro and in vivo as well as anti-tumor effects ona liver cancer xenograft model in vivo. The inhibitory effects of FP3 on angiogenesis were assessed by using human umbilical vein endothelial cells(HUVECs) in vitro and the chick embryo chorioallantoialc membrane (CAM) in viva. The inhibitory effect of FP3 on tumor growth in viva were evaluated in a human liver cancer cell line Hep-3B xenograft model in nude mice with the methods of tumor growth regression as-say. In experiments with HUVECs, FP3 inhibit-ed cell survival and tube formation. In CAM assay, FP3 suppressed MCF-7 human breast cancer cell-induced angiogenesis. In tumor growth regression assay, FP3 significantly blocked the growth of Hep-3B tumor cellin subcutaneous tumor xenograft model in nude mice. FP3 has excellent inhibitory effects on angiogenesis both in vitro and in viva and antitumor effect on liver cancer xenograft model; therefore, it might be used as an effective antiangiogenic agent in treatment of liver cancer.

Vascular endothelial growth factor induces mRNA expression of pro-inflammatory factors in the uterine cervix of mice

Inflammation is believed to play a role in uterine cervical remodeling and infection-induced preterm labor. One of the distinct features of remodeling uterine cervix is presence of prominent vascular events, such as angiogenesis, vasodilation, and vascular permeability. Although the functional significance of these features is not yet clear, we know that in most tissue types, vascular remodeling is intricately intertwined with inflammation. Since vascular endothelial growth factor (VEGF) is the major architect of vascular remodeling, we sought to examine and elucidate the potential relationship between VEGF and inflammation in the uterine cervix of non-pregnant mice. The animals used were divided into 4 treatment groups: A) negative control (vehicle only), B) positive control (lipopolysaccharide, LPS), C) recombinant VEGF-164 protein, and D) LPS + VEGF blocker (n = 3). After the appropriate treatments, the uterine cervices were harvested and analyzed using real-time PCR and confocal fluorescence microscopy. Results showed that exogenous VEGF upregulates expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α mRNAs, whereas VEGF blocker partially diminishes the LPS-induced expression of pro-inflammatory factors compared to the positive control group. We conclude that a positive feed-forward relationship likely exists between VEGF and inflammation in the uterine cervix, thus implicating VEGF in inflammation-induced preterm labor.

FP3: a novel VEGF blocker with antiangiogenic effects in vitro and antitumour effects in vivo

BACKGROUND Vascular endothelial growth factor (VEGF) is a critical promoter of blood vessel growth during embryonic development and neovascularisation in tumours. VEGF serves as a logical target for antiangiogenic cancer therapy because of its fundamental role in tumour angiogenesis. This study is to investigate the inhibitory effects of FP3, a novel VEGF blocker, on angiogenesis in vitro and tumour growth in vivo. METHODS The inhibitory effects of FP3 on angiogenesis in vitro were evaluated by using human umbilical vein endothelial cells (HUVECs) and rat aortic ring. The inhibitory effects of FP3 on tumour growth and angiogenesis in vivo were evaluated in a human non-small-cell lung cancer (NSCLC) cell line A549 tumour xenograft model with the methods of tumour growth regression assay and immunohistochemical staining, respectively. RESULTS In experiments with HUVECs, FP3 inhibited cell proliferation and migration. In rat aortic ring assay, FP3 suppressed VEGF-induced vessel sprouting. In tumour growth regression assay, FP3 significantly blocked the growth of A549 tumour in the subcutaneous tumour xenograft model and dramatically decreased the vessel density of tumour. CONCLUSIONS FP3 has excellent inhibitory effects on tumour angiogenesis both in vitro and in vivo, therefore it could be used as an effective antiangiogenic agent.

The Structural Basis for the Function of Two Anti-VEGF Receptor 2 Antibodies

The anti-VEGF receptor 2 antibody IMC-1121B is a promising antiangiogenic drug being tested for treatment of breast and gastric cancer. We have determined the structure of the 1121B Fab fragment in complex with domain 3 of VEGFR2, as well as the structure of a different neutralizing anti-VEGFR2 antibody, 6.64, also in complex with VEGFR2 domain 3. The two Fab fragments bind at opposite ends of VEGFR2 domain 3; 1121B directly blocks VEGF binding, whereas 6.64 may prevent receptor dimerization by perturbing the domain 3:domain 4 interface. Mutagenesis reveals that residues essential for VEGF, 1121B, and 6.64 binding are nonoverlapping among the three contact patches.

Abstract 3290: REGN910, a fully-human, Ang2-specific monoclonal antibody, inhibits tumor growth as a monotherapy and dramatically potentiates the effects of VEGF Trap (aflibercept)

Abstract Inhibition of tumor angiogenesis via blockade of vascular endothelial growth factor (VEGF) has proven to be beneficial in several solid tumors. However, anti-VEGF therapies are not curative; thus, there is a significant opportunity to improve efficacy through combination therapy with agents that target other essential angiogenic pathways. Angiopoietin-2 (Ang2), a ligand for the endothelial cell-specific receptor Tie2, is selectively expressed in remodeling blood vessels such as those found in tumors. Furthermore, genetic and pharmacologic data indicate that Ang2 is essential for angiogenesis in several settings. These properties make Ang2 an attractive target for specific inhibition of tumor angiogenesis. We generated a fully-human, Ang2-specific IgG1 monoclonal antibody (REGN910) using VelocImmune technology. REGN910 binds human Ang2 with very high affinity (KD ∼ 18 pM), and potently blocks its interaction with Tie2 (IC50 ∼ 50 pM), thereby inhibiting downstream signaling. In contrast, REGN910 exhibits no binding to Ang1, a Tie2 ligand that is broadly-expressed in normal tissues, and has no effect on Ang1/Tie2 signaling. In tumor xenograft models, REGN910 significantly inhibited the growth of several tumor types in a dose-dependent manner, including PC3 (prostate), Colo205 (colorectal) and A431 (epidermoid carcinoma). Furthermore, the combination of REGN910 plus the potent VEGF blocker aflibercept (VEGF Trap) inhibited tumor growth significantly better than the single agents in both the Colo205 and MMT models, promoting significant regression of Colo205 tumors. Consistent with the potent effect of this combination on tumor growth, REGN910 plus aflibercept reduced Colo205 tumor vascularity and tumor perfusion much more dramatically than the single agents, as monitored by histological and micro-ultrasound analyses. Thus, REGN910 significantly potentiates the effect of VEGF blockade on the function of tumor blood vessels, even in a tumor model (Colo205) that is very sensitive to anti-VEGF therapy. These results indicate that REGN910 is a promising candidate to selectively inhibit tumor angiogenesis, both as a single agent and in combination with anti-VEGF therapies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3290. doi:10.1158/1538-7445.AM2011-3290

VEGF blockade inhibits angiogenesis and reepithelialization of endometrium

Despite extensive literature on vascular endothelial growth factor (VEGF) expression and regulation by steroid hormones, the lack of clear understanding of the mechanisms of angiogenesis in the endometrium is a major limitation for use of antiangiogenic therapy targeting endometrial vessels. In the current work, we used the rhesus macaque as a primate model and the decidualized mouse uterus as a murine model to examine angiogenesis during endometrial breakdown and regeneration. We found that blockade of VEGF action with VEGF Trap, a potent VEGF blocker, completely inhibited neovascularization during endometrial regeneration in both models but had no marked effect on preexisting or newly formed vessels, suggesting that VEGF is essential for neoangiogenesis but not survival of mature vessels in this vascular bed. Blockade of VEGF also blocked reepithelialization in both the postmenstrual endometrium and the mouse uterus after decidual breakdown, evidence that VEGF has pleiotropic effects in the endometrium. In vitro studies with a scratch wound assay showed that the migration of luminal epithelial cells during repair involved signaling through VEGF receptor 2-neuropilin 1 (VEGFR2-NP1) receptors on endometrial stromal cells. The leading front of tissue growth during endometrial repair was strongly hypoxic, and this hypoxia was the local stimulus for VEGF expression and angiogenesis in this tissue. In summary, we provide novel experimental data indicating that VEGF is essential for endometrial neoangiogenesis during postmenstrual/postpartum repair.

A Novel Antiapoptotic Role for α1-Antitrypsin in the Prevention of Pulmonary Emphysema

There is growing evidence that alveolar cell apoptosis plays an important role in emphysema pathogenesis, a chronic inflammatory lung disease characterized by alveolar destruction. The association of alpha1-antitrypsin deficiency with the development of emphysema has supported the concept that protease/antiprotease imbalance mediates cigarette smoke-induced emphysema. We propose that, in addition to its antielastolytic effects, alpha1-antitrypsin may have broader biological effects in the lung, preventing emphysema through inhibition of alveolar cells apoptosis. METHODS, MEASUREMENTS, AND MAIN RESULTS: Transduction of human alpha1-antitrypsin via replication-deficient adeno-associated virus attenuated airspace enlargement and emphysema caused by inhibition of vascular endothelial growth factor (VEGF) receptors with SU5416 in mice, a model of apoptosis-dependent emphysema lacking neutrophilic inflammation. The overexpressed human serine protease inhibitor accumulated in lung cells and suppressed caspase-3 activation and oxidative stress in lungs treated with the VEGF blocker or with VEGF receptor-1 and -2 antibodies. Similar results were obtained in SU5416-treated rats given human alpha1-antitrypsin intravenously. Our findings suggest that inhibition of structural alveolar cell apoptosis by alpha1-antitrypsin represents a novel protective mechanism of the serpin against emphysema. Further elucidation of this mechanism may extend the therapeutic options for emphysema caused by reduced level or loss of function of alpha1-antitrypsin.

Angiogenic activity of swine granulosa cells: effects of hypoxia and vascular endothelial growth factor Trap R1R2, a VEGF blocker

The possible role played by hypoxia and vascular endothelial growth factor (VEGF) in the regulation of follicular angiogenesis was studied in a three-dimensional fibrin gel model. Granulosa cells from follicles > 5 mm were subjected to normoxia (19% O 2), partial (5% O 2) or total (1% O 2) hypoxia and their culture media were collected and used to stimulate porcine Aortic Endothelial Cells (AOC) included in the fibrin matrix. A suspension of AOC on microcarrier beads was pipetted in a fibrinogen solution (1 mg/ml PBS) before the addition of 1250 IU thrombine (250 μl) to catalize the gel formation. Granulosa cell conditioned media were tested in the presence or absence of VEGF Trap R1R2 (150 ng/ml), a potent VEGF inhibitor, that had its efficacy tested by adding VEGF (100 ng/ml) to AOC culture. Endothelial cell proliferation was measured at 48, 96, 144, 192 h by means of Scion Image Beta. A significant ( p < 0.01) increase of AOC proliferation at each time of measurement was induced by culture media from granulosa cells subjected to partial (except at the end of the first 48 h) and total hypoxia compared to control and normoxia conditions, and by VEGF. VEGF Trap significantly ( p < 0.01) inhibited the stimulatory effect of media conditioned by granulosa cells cultured in hypoxic conditions. These data suggest that hypoxia stimulates angiogenic activity of granulosa cells possibly by means of VEGF which could represent the main effector in promoting endothelial cell proliferation.