Recombinant Human Vascular Endothelial Growth Research Articles

A single dose of VEGF-A circular RNA sustains in situ long-term expression of protein to accelerate diabetic wound healing

Diabetic foot ulcer (DFU), which is characterised by damage to minute blood vessels or capillaries around wounds, is one of the most serious and dreaded complications of diabetes. It is challenging to repair chronic non-healing DFU wounds. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and promotes wound healing in DFU. However, it is difficult to sustainably deliver VEGF to the wound site owing to its poor stability and easy degradation. To overcome this challenge, lipid nanoparticles (LNP) encapsulating circular RNA (circRNA) encoding VEGF-A have been developed to continuously generate and release VEGF-A and accelerate diabetic wound healing. First, VEGF-A circRNA was synthesized using group I intron autocatalysis strategy and confirmed by enzyme digestion, polymerase chain reaction, and sequencing assay. VEGF-A circRNA was encapsulated in ionizable lipid U-105-derived LNP (U-LNP) using microfluidic technology to fabricate U-LNP/VEGF-A circRNA. For comparison, a commercially ionizable lipid ALC-0315-derived LNP (A-LNP) encapsulating circRNA (A-LNP/circRNA) was used. Dynamic light scattering and transmission electron microscopy characterization indicated that U-LNP/circRNA had spherical structure with an average diameter of 108.5 nm, a polydispersity index of 0.22, and a zeta potential of -3.31 mV. The messenger RNA (mRNA) encapsulation efficiency (EE%) of U-LNP was 87.12%. In vitro transfection data confirmed better stability and long-term VEGF-A expression of circRNA compared with linear mRNA. Assessment of cytotoxicity and innate immunity further revealed that U-LNP/circRNA was biocompatible and induced a weak congenital immune response. Cell scratch and angiogenesis tests demonstrated the bioactivity of U-LNP/VEGF-A circRNA owing to its VEGF-A expression. In situ bioluminescence imaging of firefly luciferase (F-Luc) probe and ELISA demonstrated that circRNA had long-term and strong expression of VEGF-A in the first week, and a gradual decrease in the next week at the wound site and surrounding areas. Finally, a diabetic mouse model was used to validate the healing effect of U-LNP/VEGF-A circRNA formulation. The results showed that a single dose of U-LNP/VEGF-A circRNA administered by dripping resulted in almost complete wound recovery on day 12, which was significantly superior to that of U-LNP/VEGF-A linear mRNA, and it also outperformed recombinant human vascular endothelial growth factor (rhVEGF) injection and A-LNP/circRNA dripping. Histological analysis confirmed the healing efficiency and low toxicity of U-LNP/VEGF-A circRNA formulation. Together, VEGF-A circRNA delivered by U-105-derived LNP showed good performance in wound healing, which was ascribed to the long-term expression and continuous release of VEGF-A, and has potential applications for the treatment of diabetic foot ulcer wounds.

Enhancing diabetic wound healing through anti-bacterial and promoting angiogenesis using dual-functional slow-release microspheres-loaded dermal scaffolds

Bacterial infections and the degeneration of the capillary network comprise the primary factors that contribute to the delayed healing of diabetic wounds. However, treatment modalities that cater to effective diabetic wounds healing in clinical settings are severely lacking. Herein, a dual-functional microsphere carrier was designed, which encapsulates polyhexamethylene biguanide (PHMB) or recombinant human vascular endothelial growth factor (rhVEGF) together. The in vitro release experiments demonstrated that the use of the microspheres ensured the sustained release of the drugs (PHMB or rhVEGF) over a period of 12 days. Additionally, the integration of these controlled-release microspheres into a dermal scaffold (DS-PLGA@PHMB/rhVEGF) imbued both antibacterial and angiogenic functions to the resulting material. Accordingly, the DS-PLGA@PHMB/rhVEGF scaffold exhibited potent antibacterial properties, effectively suppressing bacterial growth and providing a conducive environment for wound healing, thereby addressing the drawbacks associated with the susceptibility of rhVEGF to deactivation in inflammatory conditions. Additionally, the histological analysis revealed that the use of the DS-PLGA@PHMB/rhVEGF scaffold accelerated the process of wound healing by inhibiting inflammatory reactions, stimulating the production of collagen formation, and enhancing angiogenesis. This provides a novel solution for enhancing the antibacterial and vascularization capabilities of artificial dermal scaffolds, providing a beacon of hope for improving diabetic wound healing.

Injectable bioactive poly(propylene fumarate) and polycaprolactone based click chemistry bone cement for spinal fusion in rabbits.

Degenerative spinal pathology is a widespread medical issue, and spine fusion surgeries are frequently performed. In this study, we fabricated an injectable bioactive click chemistry polymer cement for use in spinal fusion and bone regrowth. Taking advantages of the bioorthogonal click reaction, this cement can be crosslinked by itself eliminating the addition of a toxic initiator or catalyst, nor any external energy sources like UV light or heat. Furthermore, nano-hydroxyapatite (nHA) and microspheres carrying recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF) were used to make the cement bioactive for vascular induction and osteointegration. After implantation into a rabbit posterolateral spinal fusion (PLF) model, the cement showed excellent induction of new bone formation and bridging bone, achieving results comparable to autograft control. This is largely due to the osteogenic properties of nano-hydroxyapatite (nHA) and the released rhBMP-2 and rhVEGF growth factors. Since the availability of autograft sources is limited in clinical settings, this injectable bioactive click chemistry cement may be a promising alternative for spine fusion applications in addressing various spinal conditions.

Bioactive Moldable Click Chemistry Polymer Cement with Nano-Hydroxyapatite and Growth Factor-Enhanced Posterolateral Spinal Fusion in a Rabbit Model.

Spinal injuries or diseases necessitate effective fusion solutions, and common clinical approaches involve autografts, allografts, and various bone matrix products, each with limitations. To address these challenges, we developed an innovative moldable click chemistry polymer cement that can be shaped by hand and self-cross-linked in situ for spinal fusion. This self-cross-linking cement, enabled by the bioorthogonal click reaction, excludes the need for toxic initiators or external energy sources. The bioactivity of the cement was promoted by incorporating nanohydroxyapatite and microspheres loaded with recombinant human bone morphogenetic protein-2 and vascular endothelial growth factor, fostering vascular induction and osteointegration. The release kinetics of growth factors, mechanical properties of the cement, and the ability of the scaffold to support in vitro cell proliferation and differentiation were evaluated. In a rabbit posterolateral spinal fusion model, the moldable cement exhibited remarkable induction of bone regeneration and effective bridging of spine vertebral bodies. This bioactive moldable click polymer cement therefore presents a promising biomaterial for spinal fusion augmentation, offering advantages in safety, ease of application, and enhanced bone regrowth.

Development of a prototype of a theranostic system based on silica nanoparticles with immobilized fluorescent dyes and VEGF targeting ligand.

Background. Administration of certain drugs causes undesirable effects associated with the systemic effect of the active substance on the entire body. Selective targeting of the drug to the affected tissue promotes a selective increase in the concentration of the substance in the area of interest, thereby reducing the systemic effect and enhancing the local therapeutic effect.Objective. Development of a targeted delivery system for theranostic agents using recombinant human vascular endothelial growth factor type A (rhVEGF-A121) as a targeting ligand.Design and method. To create the theranostic complex, commercially available reagents were used: the recombinant protein rhVEGF-A121 (cat.#: PSG140-10, LLC CyStorLab, Skolkovo, Russia) and fumed silica Aerosil (A-200, Degussa AG, Germany). The tosyl spacer that interconnects both components was synthesized in the laboratory. Protein conjugation with fluorophores was also carried out in-house. Indocyanine green (ICG; Sigma-Aldrich, USA) and rhodamine B (JSC Lenreaktiv, St. Petersburg, Russia) were taken for immobilization.Results. In the course of the work, functionalization of silica nanoparticles (SiNPs) with a tosyl spacer was carried out, conjugates of SiNPs with rhVEGF-A121 were synthesized, and theranostic constructs based on SiNPs were obtained, including rhVEGF-A121 as a targeting ligand, and ICG/Rhodamine B as a visualizing label.Conclusion. In the presented study, a prototype of a complex for targeted delivery of a theranostic agent to tissues with an active angiogenesis process, for example, to tumor and ischemic tissues, was developed. To solve the problem, we immobilized on the surface of SiNP a recombinant protein of human vascular endothelial growth factor (rhVEGF) to use as a guide ligand. Such a synthetic construct will help to deliver diagnostic and/ or medicinal substances packed in SiNP directly to cells that overexpress extracellular specific receptors of the VEGFR family. In subsequent in vivo experiments, delivery efficiency will be assessed by tissue accumulation of the fluorophores ICG and rhodamine B, which have been conjugated to the targeting ligand protein. The physicochemical characteristics of the obtained samples were studied by the methods of spectrophotometry and dynamic light scattering.

Development of a Silk Fibroin-Small Intestinal Submucosa Small-Diameter Vascular Graft with Sequential VEGF and TGF-β1 Inhibitor Delivery for In Situ Tissue Engineering.

Proper endothelialization and limited collagen deposition on the luminal surface after graft implantation plays a crucial role to prevent the occurrence of stenosis. To achieve these conditions, a biodegradable graft with adequate mechanical properties and the ability to sequentially deliver therapeutic agents isfabricated. In this study, a dual-release system is constructed through coaxial electrospinning by incorporating recombinant human vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1) inhibitor into silk fibroin (SF) nanofibers to form a bioactive membrane. The functionalized SF membrane as the inner layer of the graft is characterized by the release profile, cell proliferation and protein expression. It presents excellent biocompatibility and biodegradation, facilitating cell attachment, proliferation, and infiltration. The core-shell structure enables rapid VEGF release within 10 days and sustained plasmid delivery for 21 days. A 2.0-mm-diameter vascular graft is fabricated by integrating the SF membrane with decellularized porcine small intestinal submucosa (SIS), aiming to facilitate the integration process under a stable extracellular matrix structure. The bioengineered graft is functionalized with the sequential administration of VEGF and TGF-β1, and with the reinforced and compatible mechanical properties, thereby offers an orchestrated solution for stenosis with potential for in situ vascular tissue engineering applications.

A phase Ib trial of the VEGF fusion protein HB002.1T plus chemotherapy in patients with advanced solid tumors.

2530 Background: HB002.1T is a recombinant human vascular endothelial growth factor receptor (VEGF)-IgG Fc fusion protein, which functions as a decoy receptor to bind VEGF-A, VEGF-B and placental growth factor (PlGF). In phase Ia, HB002.1T monotherapy showed encouraging anti-tumor activity in gallbladder cancer. Methods: This study aimed to evaluate efficacy and safety of HB002.1T plus chemotherapy (mainly based on platinum, paclitaxel, gemcitabine, etc.) in advanced solid tumors. The tumor assessment was evaluated by investigator according to RECIST v1.1. The study included part 1 and part 2, part 1 study was dose escalation (12mg/kg, 16mg/kg Q3W) and dose expansion conducted in patients (pts) with advanced solid tumors, part 2 study was dose expansion (16mg/kgQ3W) in specified tumors (cohort 1: ovarian and cervical, cohort 2: pancreatic, gallbladder and bile duct cancer). Results: As of Dec 20,2022,68 (42F/26M) advanced solid tumor pts were enrolled in the study with 32 pts in part 1 and 36 pts in part 2. 33.3% pts failed at least 3 lines of therapy before enrollment. 63(92.6%) pts had stage IV disease. Median age was 58. It is to be note that 12 efficacy assessment evaluablepts with ovarian cancer (1 with 12mg/kg in part 1,11with 16mg/kg in part 2) were all stage IV, which included 3 complete response (CR),6 partial responses (PR) and 3 stable disease (SD). Median progression free survival (PFS) was 7.3 months and 6-month PFS rate was 58.3%. The ORR and DCR were 75%, 100% respectively. The most common treatment related adverse events (TRAEs) included neutropenia (9/12, 75.0%) and leukocytopenia (8/12, 66.7%). 8 (8/12, 66.7%) pts had grade ≥ 3 TRAEs, which neutropenia (4/12, 33.3%) and leukocytopenia (3/12, 25.0%) were commonly observed. Part 1: In 28 pts whose tumor assessment were available, including 1 gastric cancer patient achieved CR, 11 pts achieved PR (2 gastric, 2 ovarian, 2 cervical, 1 maxillary, 1 lung, 1 parotid, 1 nasopharynx, 1 pancreatic) and 15 achieved SD. Part 2: 32 pts were available for tumor assessment, including 4 achieved CR (3 ovarian, 1 cervical), 10 achieved PR (4 ovarian, 2 cervical, 3 bileduct, 1 pancreatic), and 16 achieved SD. Overall, in Part 1 and 2, TRAEs occurred in 64 (64/68, 94.1%) pts. The most common TRAEs were leukocytopenia (28/68, 41.2%), neutropenia (26/68, 38.2%) and proteinuria (25/68, 36.8%). 34 (34/68, 50.0%) pts had grade ≥ 3 TRAEs, which neutropenia (15/68, 22.1%) and leukocytopenia (11/68, 16.2%) were commonly observed. TRAE leading to discontinuation occurred in 3 pts. No death was reported related with HB002.1T. Conclusions: The Pts were well tolerated to 12mg/kg and 16mg/kg HB002.1T dose combined with chemotherapy, and HB002.1T showed acceptable safety profile. As well as, promising anti-tumor activity was observed in various tumors, especially in advanced ovarian cancer. More data is being accumulated, and confirmatory clinical trials are being prepared. Clinical trial information: NCT04802980 .

THERAPY OF PERIODONTITIS WITH VASCULAR ENDOTHELIAL GROWTH FACTOR BASED ON HYDROGEL: IMMUNOHISTOCHEMICAL CHARACTERISTICS

Regeneration of lost periodontal tissues is the ultimate goal of periodontal treatment. One of the promising approaches to stimulating periodontal regeneration is the use of hydrogels and various growth factors that contribute to the colonization of the scaffold with fibroblast populations, followed by the formation of mature connective tissue of the periodontal ligament. Patients with chronic generalized periodontitis of mild and moderate severity (n=70, age 49-69 years) were treated in the Department of maxillofacial surgery of the UKB No. 4. Treatment was carried out with a preparation from a complex of bioresorbable carbohydrates and recombinant human vascular endothelial growth factor (VEGF-A). The biopsy material was taken immediately before the introduction of the drug into the periodontal pocket and 14 days after the procedure. Prior to treatment, pronounced chronic inflammation with a predominance of lymphocytes, moderate edema and divergence of the fibers of the stromal component were noted in the gum preparations, signs of chronic moderate active inflammation were observed. After treatment, collagen fibers constructed from type III collagen and type I collagen were found in the structured fibers of the intercellular substance, which is characteristic of the formed connective tissue. Thus, the therapy of chronic periodontitis with a hydrogel with VEGF-A is a promising direction for further research, since it has the potential to influence not only stimulating the regeneration of periodontal tissues, but also the effect of local anti-inflammatory treatment.

Development of a system of heparin multilayers on titanium surfaces for dual growth factor release.

The aim of the present study was to establish a modular platform of poly-L-lysine-heparin (PLL-Hep) polyelectrolyte multilayer (PEM) coatings on titanium surfaces for dual growth factor delivery of recombinant human bone morphogenic protein 2 (rhBMP2) and recombinant human vascular endothelial growth factor 165 (rhVEGF165) in clinically relevant quantities. Release characteristics for both growth factors differed significantly depending on film architecture. rhBMP2 induced activation of alkaline phosphatase in C2C12 cells and proliferation of human mesenchymal stem cells (hMSCs). rhVEGF mediated induction of von Willebrand factor (vWF) in hMSCs and proliferation of human umbilical vein endothelial cells. Osteogenic and angiogenic effects were modified by variation in cross-linking and architecture of the PEMs. By creating multilayer films with distinct zones, release characteristics and proportion of both growth factor delivery could be tuned and surface-activity modified to enhance angiogenic or osteogenic function in various ways. In summary, the system provides a modular platform for growth factor delivery that allows for individual composition and accentuation of angiogenic and osteogenic surface properties.

Role of Micro-RNA in the Regulation of Cell Polarization in Hepatocellular Carcinoma

The occurrence of tissue scarring and architecture-modifying signaling led to a tumorigenic microenvironment. Targeting specifically the biological mediators responsible for the physiological and morphological changes accommodating hepatocellular carcinoma (HCC) growth may be the key for identifying a future HCC cure. Morphological and physiological features of cultured HepG2 cells in both stimulated recombinant human vascular endothelial growth factor (VEGF165) and unstimulated (control) conditions were assessed. Quantitative reverse transcription (RT)-PCR measured endogenous VEGF expression levels. The assessment of proangiogenic biological mediator (micro RNA [miR]-296, miR-31, and miR-17) profiles was achieved by polarization-inducing VEGF165 stimulation followed by quantitative RT-PCR. In vitro conditions reproduced successfully the physiological environment leading to the occurrence of HCC, including the successful HepG2 polarization following VEGF stimulation. While endogenous VEGF production only occurs if complete polarization has been reached, the quantified biological mediator profiles determined here pointed at either possible early stages of depolarization or at the lack of tumorigenic potential of the HepG2 cells. All tested miRs displayed upregulated profiles, although miR-296 was less amplified (3.78-fold compared with control) than miR-31 or miR-17 (6.5- and 6.6-fold, respectively). The findings surrounding miR-17 reproduce similar data reported in the literature; the unexpected high miR-31 expression was intriguing. Given HepG2 cells' minimal tumorigenic potential, the unexpected multifold upregulation of miR-31 may be a cause or a consequence of HepG2 cells' low tumorigenic potential. The exploration of miR-31 therapeutic potential may be a future rewarding endeavor.

Production of high-purity recombinant human vascular endothelial growth factor (rhVEGF165) by Pichia pastoris

Vascular endothelial growth factor (VEGF165) is a highly specific vascular endothelial growth factor that can be used to treat many cardiovascular diseases. The development of anti-tumor drugs and disease detection reagents requires highly pure VEGF165 (at least 95% purity). To date, the methods for heterologous expression and purification of VEGF165 require multiple purification steps, but the product purity remains to be low. In this study, we optimized the codons of the human VEGF165 gene (vegf165) according to the yeast codon preference. Based on the Pichia pastoris BBPB vector, we used the Biobrick method to construct a five-copy rhVEGF165 recombinant expression vector using Pgap as the promoter. In addition, a histidine tag was added to the vector. Facilitated by the His tag and the heparin-binding domain of VEGF165, we were able to obtain highly pure rhVEGF165 (purity > 98%) protein using two-step affinity chromatography. The purified rhVEGF165 was biologically active, and reached a concentration of 0.45 mg/mL. The new design of the expression vector enables production of active and highly pure rhVEGF165 ) in a simplified purification process, the purity of the biologically active natural VEGF165 reached the highest reported to date.

Enhanced Neovascularization Using Injectable and rhVEGF‐Releasing Cryogel Microparticles

Cryogels are gel networks or scaffolds with a large porous structure; they can be tailored for injectability and for possessing a shape-memory ability. Herein, a growth factor-releasing cryogel microparticle (CMP) system is fabricated, and the therapeutic efficacy of recombinant human vascular endothelial growth factor (rhVEGF)-loaded CMP (V-CMP) for neovascularization is investigated. To prepare the cryogels, both methacrylated chitosan (Chi-MA) and methacrylated chondroitin sulfate (CS-MA) are used, and crosslinking using a radical crosslinking reaction is established. The physical, mechanical, and biological properties of the cryogels are analyzed by varying the amount of CS-MA used. The cryogels are then pulverized, and microsized CMPs are fabricated. CMPs dispersed in saline demonstrate a shear-thinning property, and can thus be extruded through a 23G needle. Additionally, V-CMP exhibit a sustained release profile of rhVEGF and enhance the in vitro proliferation of endothelial cells. Finally, neovascularization and effective tissue necrosis prevention are observed when V-CMPs are injected into a hindlimb ischemia mouse model. Thus, the injectable V-CMP system developed herein demonstrates a high potential utility in various tissue regeneration applications based on cell or growth factor delivery.

The Effect of Autogenous Bone Graft Mixed With Recombinant Human Vascular Endothelial Growth Factor on Bone Regeneration.

Bone regeneration depends on vascularization in the pertaining site. This study aims to investigate autogenous bone grafts mixed with recombinant human vascular endothelial growth factor (rhVEGF) effect on bone regeneration in rat mandibular bone defect. Using 32 Wistar Albino rats, our experimental study consists of 4 groups: Group1 (control group), the defect was empty; Group 2, autogenous bone graft only; Group 3, gelatin sponge plus rhVEGF applications; Group 4, autogenous bone graft plus rhVEGF applications. The rats were sacrificed on the 28th day after the operation. New bone regeneration was analyzed histologically and immunohistochemically. Our histological analyses revealed that new bone regeneration in Group 3 was enhanced in comparison to Group 1 and Group 2. However, autogenous bone grafts combined with rhVEGF provided the best outcome in conjunction with the increased remodeling of the new bone. In the light of our results, it can be concluded that autogenous bone grafts in combination with rhVEGF can, potentially, enhance neovascularization and bone regeneration.

Vertical Guided Bone Regeneration in the Rabbit Calvarium Using Porous Nanohydroxyapatite Block Grafts Coated with rhVEGF165 and Cortical Perforation.

IntroductionVertical bone augmentation without osseous walls to support the stability of clots and bone grafts remains a challenge in dental implantology. The objectives of this study were to confirm that cortical perforation of the recipient bed is necessary and to evaluate whether nanohydroxyapatite (nHA) block grafts coated with recombinant human vascular endothelial growth factor165 (rhVEGF165) and cortical perforation can improve vertical bone regeneration.Materials and MethodsWe prepared nHA blocks coated with or without rhVEGF165 on the rabbit calvarium through cortical perforation, and designated the animals as the nonperforated group (N-nHA), rhVEGF165 group (NV-nHA), perforated group (P-nHA) and rhVEGF165 on perforated group (PV-nHA). Micro-computed tomography (micro-CT) and fluorescence microscopy were selected to evaluate parameters of vertical bone regeneration at 4 and 6 weeks.ResultsThe ratio of the newly formed bone volume to the titanium dome volume (BV/TV) and the bone mineral density (BMD) were significantly higher in the PV-nHA group than in the N-nHA group at 4 and 6 weeks, as determined using micro-CT. The fluorescence analysis showed slightly greater increases in new bone regeneration (NB%) and vertical height (VH%) gains in the P-nHA group than in the N-nHA group. Greater increases in NB% and VH% were observed in groups treated with rhVEGF165 and perforation than in the blank groups, with significant differences detected at 4 and 6 weeks (N-nHA compared with PV-nHA, p<0.05). A greater VH% that was observed at the midline of the block in the PV-nHA group than in the other three groups at both time points (0.75±0.53% at 4 weeks and 0.83±0.42% at 6 weeks).ConclusionAccording to the present study, cortical perforation is necessary and nHA blocks coated with rhVEGF165 and decoration could work synergistically to improve vertical bone regeneration by directly affecting primary osteoblasts and promoting angiogenesis and osteoinduction.

Persistent Pulmonary Hypertension of the Newborn: Pathophysiological Mechanisms and Novel Therapeutic Approaches.

Persistent pulmonary hypertension of the newborn (PPHN) is one of the main causes of neonatal morbidity and mortality. It is characterized by sustained elevation of pulmonary vascular resistance (PVR), preventing an increase in pulmonary blood flow after birth. The affected neonates fail to establish blood oxygenation, precipitating severe respiratory distress, hypoxemia, and eventually death. Inhaled nitric oxide (iNO), the only approved pulmonary vasodilator for PPHN, constitutes, alongside supportive therapy, the basis of its treatment. However, nearly 40% of infants are iNO resistant. The cornerstones of increased PVR in PPHN are pulmonary vasoconstriction and vascular remodeling. A better understanding of PPHN pathophysiology may enlighten targeted and more effective therapies. Sildenafil, prostaglandins, milrinone, and bosentan, acting as vasodilators, besides glucocorticoids, playing a role on reducing inflammation, have all shown potential beneficial effects on newborns with PPHN. Furthermore, experimental evidence in PPHN animal models supports prospective use of emergent therapies, such as soluble guanylyl cyclase (sGC) activators/stimulators, l-citrulline, Rho-kinase inhibitors, peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists, recombinant superoxide dismutase (rhSOD), tetrahydrobiopterin (BH4) analogs, ω-3 long-chain polyunsaturated fatty acids (LC-PUFAs), 5-HT2A receptor antagonists, and recombinant human vascular endothelial growth factor (rhVEGF). This review focuses on current knowledge on alternative and novel pathways involved in PPHN pathogenesis, as well as recent progress regarding experimental and clinical evidence on potential therapeutic approaches for PPHN.

Intracerebroventricular delivery of vascular endothelial growth factor in patients with amyotrophic lateral sclerosis, a phase I study.

We studied the feasibility, safety, tolerability and pharmacokinetics of intracerebroventricular delivery of recombinant human vascular endothelial growth factor in patients with amyotrophic lateral sclerosis. In this phase I study in patients with amyotrophic lateral sclerosis, the study drug was delivered using an implantable programmable pump connected to a catheter inserted in the frontal horn of the lateral cerebral ventricle. A first cohort received open label vascular endothelial growth factor (0.2, 0.8 and 2 µg/day), a second cohort received placebo, 0.8 or 2 µg/day of study dug. After the 3-month study period, all patients could participate in an open label extension study. In total, 18 patients with amyotrophic lateral sclerosis, seen at the University Hospitals in Leuven were included. The surgical procedure was well tolerated in most patients. One patient had transient postoperative seizures, due to an ischemic lesion along the catheter tract. The first 3-month study period was completed by 15/18 patients. Administration of 2 µg/day vascular endothelial growth factor resulted in sustained detectable levels in cerebrospinal fluid. A pulmonary embolus occurred in 3 patients, in 1 patient in the first 3-month study, and in 2 patients during the open label extension study. The study drug was well tolerated in the other patients, for up to 6 years in the open label extension study. Our study shows that intracerebroventricular administration of 2 µg/day of vascular endothelial growth factor to patients with amyotrophic lateral sclerosis is feasible, results in detectable cerebrospinal fluid levels and is well tolerated in most patients. The most common serious adverse event was a pulmonary embolus.

Evaluation of recombinant human vascular endothelial growth factor VEGF121-loaded poly-l-lactide microparticles as a controlled release delivery system.

Vascular endothelial growth factor A (VEGF-A) is an important growth factor that plays a major role in angiogenesis. With different isoforms distributed in various tissues, the shortest isoform of VEGF-A is VEGF121, one of the physiologically functional variants next to VEGF165. It is well known that VEGF has a shorter half-life, and the stability of the protein must be considered in therapeutic aspects. Poly-l-lactide (PLA) microparticles can release the encapsulated protein in a sustained release mode. In this study, the VEGF121 gene was cloned and expressed in a prokaryotic expression system (Escherichia coli). The recombinant VEGF121 was encapsulated with PLA microparticles and studied in vitro and ex ovo for the sustained release mechanism. The PLA-VEGF microparticles and the recombinant VEGF121 were explored for their bioactivity in human umbilical vein endothelial cells (HUVEC). VEGF released in vitro from PLA microparticles on days 1, 20, and 30 showed remarkable biological activity compared to PBS-loaded PLA microparticles such as the ability of the cells to proliferate, migrate, and form tubes similar to recombinant VEGF121. Besides, PLA-VEGF microparticles and the recombinant VEGF121 were also tested for their proangiogenic action in embryonated eggs by chicken chorioallantoic membrane assay (CAM), and the effect was observed in both forms. This study suggests that PLA-loaded VEGF microparticles in a sustainable release format can be effectively used in proangiogenic therapy and reduce the adverse effects caused due to multiple dosages.

Systemic Sclerosis Serum Significantly Impairs the Multi-Step Lymphangiogenic Process: in Vitro Evidence.

In systemic sclerosis (SSc), the possible involvement of lymphatic microcirculation and lymphangiogenesis has traditionally been overshadowed by the greater emphasis placed on dysfunctional blood vascular system and angiogenesis. In the present in vitro study, we explore for the first time whether the SSc microenvironment may interfere with lymphangiogenesis, a complex, multi-step process in which lymphatic microvascular endothelial cells (LMVECs) sprout, migrate, and proliferate to generate new lymphatic capillaries. Normal human adult dermal LMVECs from three donors were treated with serum from SSc patients (n = 8), serum from healthy individuals (n = 8), or recombinant human vascular endothelial growth factor (VEGF)-C as a positive control for lymphangiogenesis. Cell proliferation, Boyden chamber Matrigel chemoinvasion, wound healing capacity, and lymphatic capillary morphogenesis on Geltrex were assayed. VEGF-C serum levels were measured by enzyme-linked immunosorbent assay. Gene and protein expression levels of the lymphangiogenic orchestrators VEGF receptor-3 (VEGFR-3)/Flt-4 and neuropilin-2 (NRP-2) were determined by real-time PCR and Western blotting, respectively. Conditioning with SSc serum significantly inhibited LMVEC proliferation, Matrigel invasion, and wound healing capacity with respect to healthy serum. The ability of LMVECs to form lymphatic tubes on Geltrex was also severely compromised in the presence of SSc serum. VEGF-C levels were comparable in SSc and healthy sera. Treatment with SSc serum resulted in a significant downregulation of both VEGFR-3/Flt-4 and NRP-2 mRNA and protein levels. In SSc, the pathologic environment severely hampers every lymphangiogenesis step, likely through the reduction of pro-lymphangiogenic VEGFR-3/NRP-2 co-receptor signaling. The impairment of the lymphangiogenic process opens a new scenario underlying SSc vascular pathophysiology, which is worth investigating further.

Transgenic and cell wall-deficient Chlamydomonas reinhardtii food affects life history of Daphnia magna

The economical interest in the use of genetically modified microalgae (GMM) increases because of their potential for low-cost industrial mass cultivation, high productivity (e.g., biomass, lipids, and recombinant proteins), and short generation times. However, the unintentional release of GMMs to the environment might cause harmful biotic interactions affecting ecosystems. GMMs could invade natural ecosystems and could affect ecosystem services by biotic interactions with other species from the same trophic level, as well as organisms from higher trophic levels. So far, potential negative influences of GMMs on natural ecosystems have mainly been hypothesized and empirical studies are rare and usually consider only direct short-term effects on adult organisms. In analyzing life history effects on Daphnia magna fed with transgenic Chlamydomonas reinhardtii synthesizing and secreting recombinant human vascular endothelial growth factor VEGF-165 (VEGF), we found that neonate size, fecundity, and fitness were significantly influenced by the different C. reinhardtii food sources. Clear GMM specific effects on Daphnia resulted in lower fecundity and neonates were small in size but higher in numbers. These, especially, might be consequences of changes in behavior or metabolism in Daphnia induced by the growth-enhancing protein VEGF. The results indicate a measurable response of Daphnia life history, which can result in further effects on higher trophic levels such as planktivorous invertebrates or fish.

Expression and characterization of recombinant human VEGF165 in the middle silk gland of transgenic silkworms.

Recombinant human vascular endothelial growth factor (rhVEGF) has important applications in therapeutic angiogenesis and inhibition of VEGF-mediated pathological angiogenesis. Previous studies have shown that rhVEGF can be produced in several expression systems, including Escherichia coli, yeasts, insect cells and mammalian cells. However, little is known regarding the effective production of this protein in organs of live organisms. Here, we report for the first time the expression and characterization of rhVEGF165 in the middle silk gland (MSG) of the transgenic silkworm line S1-V165. Our results confirmed that (1) rhVEGF165 was highly expressed in MSG cells and was secreted into the cocoon of S1-V165; (2) the dimeric form of rhVEGF165 could be easily dissolved from S1-V165 cocoons using an alkaline solution; (3) rhVEGF165 extracted from S1-V165 cocoons exhibited slightly better cell proliferative activity than the hVEGF165 standard in cultured human umbilical vein endothelial cells. This study provides an alternative strategy for the production of bioactive rhVEGF165 using the MSG of transgenic silkworms.