Treatment of Focal Cerebral Ischemia with Liposomal Nerve Growth Factor

Liposomal nerve growth factor (NGF) was used for the treatment of focal cerebral ischemia in a rat model. Positive charge inducing agents of sphingosine (SP) and stearylamine (S) were formulated in the liposomal NGF. Dose-response of intraventricular injection of liposomal NGF showed significant reduction in infarct volume at the dose of 5 and 10 μ g/rat of NGF. The liposomal NGF formulated with SP or S demonstrated similar results in the reduction of total infarct volume in rats. When we increased the molar ratio of SP and S from 0.15 to 0.3, the infarct volume from rats showed a similar value as that of the control treated with NGF solution. Liposomal NGF was given prior to the development of ischemia. We found that NGF was effective in prevention of neuronal death. The NGF concentrations in brain for liposomal NGF were maintained in a level significantly higher than those for NGF solution. This was attributed to the positively charged liposomal NGF bound effectively in brain ventricle and caused longer retention time than free NGF for localization in brain. Therefore, the effect of liposomal NGF on reduction of infarct volume was significant. We assumed that the transportation of NGF might go through the cerebrospinal fluid pathway throughout the ventricular system and subarachnoid system to cerebral cortex to produce a therapeutic effect on ischemia.     

Hypoxia-Inducible Vascular Endothelial Growth Factor Gene Therapy Using the Oxygen-Dependent Degradation Domain in Myocardial Ischemia

Purpose  

A hypoxia-inducible VEGF expression system with the oxygen-dependent degradation (ODD) domain was constructed and tested to be used in gene therapy for ischemic myocardial disease.     

血管内皮生长因子与子宫内膜异位症

随着子宫内膜异位症（endometriosis,EMs）病因及发病机制研究的深入,备受大多数学者支持的内膜种植学说已无法合理解释绝大多数妇女经期存在经血逆流却只有少数发病这一现象。近年来,大量研究表明子宫内膜异位症的发生与种植部位新生血管的形成密切相关,认为经血逆流可能只是子宫内膜异位症发生的一个前提条件,而血供的建立和维持才是其发生的基本。而血管内皮生长因子作为目前所知作用最强的促血管生长因子,其与子宫内膜异位症的关系也因此成为人们研究的热点。     

Growth Factor Delivery for Tissue Engineering

A tissue-engineered implant is a biologic-biomaterial combination in which some component of tissuehas been combined with a biomaterial to create a device for the restoration or modification of tissue ororgan function. Specific growth factors, released from a delivery device or from co-transplanted cells,would aid in the induction of host paraenchymal cell infiltration and improve engraftment of co-deliveredcells for more efficient tissue regeneration or ameliorate disease states. The characteristic properties ofgrowth factors are described to provide a biological basis for their use in tissue engineered devices. Theprinciples of polymeric device development for therapeutic growth factor delivery in the context of tissueengineering are outlined. A review of experimental evidence illustrates examples of growth factor deliveryfrom devices such as micropaticles, scaffolds, and encapsulated cells, for their use in the applicationareas of musculoskeletal tissue, neural tissue, and hepatic tissue.     

Nanoparticulate Systems for Growth Factor Delivery

The field of nanotechnology, which aims to control and utilize matter generally in 1–100 nm range, has been at the forefront of pharmaceutical development. Nanoparticulate delivery systems, with their potential to control drug release profiles, prolonging the presence of drugs in circulation, and to target drugs to a specific site, hold tremendous promise as delivery strategies for therapeutics. Growth factors are endogenous polypeptides that initiate intracellular signals to regulate cellular activities, such as proliferation, migration and differentiation. With improved understanding of their roles in physiopathology and expansion of their availability through recombinant technologies, growth factors are becoming leading therapeutic candidates for tissue engineering approaches. However, the outcome of growth factor therapeutics largely depends on the mode of their delivery due to their rapid degradation in vivo, and non-specific distribution after systemic administration. In order to overcome these impediments, nanoparticulate delivery systems are being harnessed for spatiotemporal controlled delivery of growth factors. This review presents recent advances and some disadvantages of various nanoparticulate systems designed for effective intact growth factor delivery. The therapeutic applications of growth factors delivered by such systems are reviewed, especially for bone, skin and nerve regeneration as well as angiogenesis. Finally, future challenges and directions in the field are presented in addition to the current limitations.     

Local and Sustained Vascular Endothelial Growth Factor Delivery for Angiogenesis Using an Injectable System

Purpose  We hypothesize that a microsphere/hydrogel combination system could be useful for the local and sustained delivery of recombinant human vascular endothelial growth factor (rhVEGF) to enhance angiogenesis in vivo. Methods  Poly(d,l-lactide-co-glycolide) (PLGA) microspheres containing rhVEGF were loaded into alginate gels by ionic cross-linking. The rhVEGF release from the system was monitored and bioactivity was tested in vitro. The combination system was subcutaneously injected into mice using a syringe, and new blood vessel formation was evaluated. Results  Sustained rhVEGF release from the combination system was observed for 3 weeks, and the released rhVEGF remained bioactive. Endothelial cell proliferation was significantly enhanced when cells were cultured with the rhVEGF-releasing combination system in vitro. When the combination system was implanted, the granulation tissue layer was thicker with more newly formed blood vessels than that with a single dose VEGF injection. Conclusion  The rhVEGF release was controlled by varying relative portions of microspheres and hydrogels in combination delivery systems, which efficiently promoted new blood vessel formation in vivo. This combination system could be a promising delivery vehicle for therapeutic angiogenesis.     

成纤维细胞生长因子与其受体的研究进展

成纤维细胞生长因子(FGFs)家族已发现有21个成员，其中哺乳动物有9个。成纤维细胞生长因子受体(FGFRs)是一类穿膜的酪氨酸激酶受体，它们介导FGFs信号传递入细胞质中。目前已经确定了由4种独立基因编码的FGFRs即FGF、R1、FGFR2、FGFR3、FGFR4。FGFs／FGFRs在不同组织中，通过复杂的信号传递路径对细胞的增值、分化和移行进行调节。由于它们具有广泛的生物学功能，因此在临床应用上具有很大的潜力。     

血塞通软胶囊促心梗后大鼠缺血心肌血管新生作用及对相关生长因子影响的研究

目的:观察血塞通软胶囊对大鼠缺血心肌血管新生作用,并探讨其机制。方法:结扎大鼠左冠状动脉后,随机分为血塞通软胶囊组、麝香保心丸组、模型组,并设假手术组。6周后检测各组大鼠缺血心肌中微血管数(MVC)、微血管密度(MVD)及血管内皮生长因子(VEGF)、碱性成纤维细胞生长因子(bFGF)、血小板衍生生长因子β(PDGF-β)、胰岛素样生长因子(IGF-1)蛋白的表达及其灰度值。结果:模型组、麝香保心丸组及血塞通软胶囊组大鼠心肌梗死(MI)边缘区MVC和MVD较假手术组明显增多(P<0．05);血塞通软胶囊组明显高于模型组(P<0．05),与麝香保心丸组相似(P>0．05)。模型组VEGF、bFGF、PDGF-β、IGF-1蛋白表达及其灰度值明显高于假手术组(P<0．05);血塞通软胶囊组明显高于模型组(P< 0．05),低于麝香保心丸组(P>0．05)。结论:血塞通软胶囊可促进大鼠缺血心肌血管新生,其机制与促进VEGF、bFGF、PDGF-β、IGF-1的表达有关。     

Polymeric Growth Factor Delivery Strategies for Tissue Engineering

Purpose. Tissue engineering seeks to replace and regrow damaged or diseased tissues and organs from either cells resident in the surrounding tissue or cells transplanted to the tissue site. The purpose of this review is to present the application of polymeric delivery systems for growth factor delivery in tissue engineering. Methods. Growth factors direct the phenotype of both differentiated and stem cells, and methods used to deliver these molecules include the development of systems to deliver the protein itself, genes encoding the factor, or cells secreting the factor. Results. Results in animal models and clinical trials indicate that these approaches may be successfully used to promote the regeneration of numerous tissue types. Conclusions. Controlling the dose, location, and duration of these factors through polymeric delivery strategies will dictate their utility in tissue regeneration.     

EGF和VEGF在创伤性骨折愈合中的变化与意义

目的探讨血清内皮生长因子(Epidermal Growth Factor,EGF)和血管内皮生长因子(Vascular Endothelial Growth Factor,VEGF)在创伤性骨折愈合中的变化及其意义。方法应用放射免疫分析对50例创伤性骨折患者进行了治疗前后血清EGF和VEGF检测,并与30名正常健康人作比较。结果创伤性骨折患者在治疗前后血清EGF和VEGF水平与正常对照组相比明显增高(P<0.05),手术治疗一月后两者水平与正常对照组相比差异无统计学意义(P>0.05),且治疗前后血清EGF和VEGF水平的变化呈正相关。结论血清EGF和VEGF水平与骨折愈合密切相关。     

Polymer Controlled Drug Delivery System for Growth Hormone

The use of biomaterials as vehicles for pharmacological agents, hormones, and growth factors is at times the best treatment for controlled local administration. Our study was designed to evaluate the in vitro biocompatibility and potential clinical use of a new polymer, hydroxyethyl methacrylate-vinyl pirrolidone. Human fibroblasts were incubated in the presence of the polymer and/or growth hormone, and evaluation was made of both the rate of polymer and hormone degradation and the proliferative effect on the fibroblast population. Results indicate that this polymer is biodegradable and lacks toxicity toward these cells. The hormone was slowly released, as suggested by enhanced cell proliferation.     

胸腺因子D对老龄大鼠生长激素的影响

目的　探讨胸腺因子 D对垂体生长激素 ( GH)老龄性改变的逆转作用。 方法 　雌、雄 2 1月老龄 SD大鼠各随机分成两组 ,一组隔日背部皮下注射胸腺因子 D2 mg· kg- 1 ,另一组及 6月青龄雌、雄对照组注射等量生理盐水 :连续处理 3个月后 ,用放射免疫法测定腺垂体组织和血清生长激素。结果 　与雄性青龄对照组相比 ,雄性老年组血清 GH升高 ,垂体组织 GH呈下降趋势 ;给药后 ,这些老年性改变可部分得到改善 ;血清GH在各雌性大鼠间无差异。 结论 　胸腺因子 D可逆转老龄雄性大鼠生长激素的老龄性改变 ,从而延缓衰老     

Heparin Immobilized Porous PLGA Microspheres for Angiogenic Growth Factor Delivery

Purpose Heparin immobilized porous poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres were prepared for sustained release of basic fibroblast growth factor (bFGF) to induce angiogenesis.Materials and Methods Porous PLGA microspheres having primary amine groups on the surface were prepared using an oil-in-water (O/W) single emulsion method using Pluronic F-127 as an extractable porogen. Heparin was surface immobilized via covalent conjugation. bFGF was loaded into the heparin functionalized (PLGA-heparin) microspheres by a simple dipping method. The bFGF loaded PLGA-heparin microspheres were tested for in vitro release and in vivo angiogenic activity.Results PLGA microspheres with an open-porous structure were formed. The amount of conjugated amine group onto the microspheres was 1.93 ± 0.01 nmol/mg-microspheres, while the amount of heparin was 95.8 pmol/mg-microspheres. PLGA-heparin microspheres released out bFGF in a more sustained manner with a smaller extent of initial burst than PLGA microspheres, indicating that surface immobilized heparin controlled the release rate of bFGF. Subcutaneous implantation of bFGF loaded PLGA-heparin microspheres in mice significantly induced the formation of new vascular microvessels.Conclusions PLGA microspheres with an open porous structure allowed significant amount of heparin immobilization and bFGF loading. bFGF loaded PLGA-HP microspheres showed sustained release profiles of bFGF in vitro, demonstrating reversible and specific binding of bFGF to immobilized heparin. They also induced local angiogenesis in vivo in an animal model.     

Vascular Endothelial Growth Factor Gene Delivery for Revascularization in Transplanted Human Islets

PURPOSE: Islet transplantation is limited by islet graft failure because of poor revascularization, host immune rejection, and nonspecific inflammatory response. Human vascular endothelial growth factor (hVEGF) gene delivery is likely to promote islet revascularization and survival. METHODS: We evaluated gene expression from a bicistronic plasmid encoding hVEGF and enhanced green fluorescent protein (EGFP) (pCMS-EGFP-hVEGF). Glucose responsiveness of islets was evaluated both in vitro and in vivo, and revascularization in islet graft was evaluated by immunohistochemistry. RESULTS: After transfection, hVEGF and EGFP expression levels were comparable with original monocistronic plasmids in Jurkat cells but higher and prolonged hVEGF expression in islets transfected with the bicistronic plasmid was observed, possibly as the result of differences in promoter strength and hypoxia response. The 3:1 w/w complexes showed little toxicity to islets at a dose of 5 microg DNA per 2000 islets. On glucose challenge, insulin release from transfected islets as well as secretion from islets after transplantation under the mouse kidney capsules in response to glucose stimulation, increased with time. Immunohistochemical staining of transplanted islets using mouse anti-human insulin, mouse anti-human von Willebrand factor, and rat anti-mouse CD31 antibodies suggests that islets are functional and there is new blood vessel formation. CONCLUSIONS: These findings suggest that transient hVEGF gene expression by the islets may promote islet revascularization and prolong islet survival after transplantation.     

消化性溃疡患者尿中表皮生长因子含量测定的意义

用放射免疫方法对15例消化性溃疡、10例慢性浅表性胃炎和10例健康成人尿中表皮生长因子含量进行了测定。消化性溃疡和浅表性胃炎浓度分别为82.6±9.72μg/L 和129.2±24.2μ/L。消化性溃疡患者尿中表皮生长因子含量显著低于正常对照组(P<0.01),而慢性浅表性胃炎与对照组相比无显著意义(P>0.05)。结果提示表皮生长因子缺乏可能是消化性溃疡的病因之一。     

Intracranial Delivery of Recombinant Nerve Growth Factor: Release Kinetics and Protein Distribution for Three Delivery Systems

Purpose. Three different polymeric delivery systems, composed of either poly(ethylene-co-vinyl acetate) (EVAc) or poly(lactide-co-gly-colide) (PLGA), were used to administer recombinant human nerve growth factor (rhNGF) intracranially in rats. Methods. The delivery systems were characterized with respect to release kinetics, both in the brain and in well-stirred buffer solutions. Results. During incubation in buffered saline, the delivery systems released rhNGF in distinct patterns: sustained (EVAc), immediate (PLGA₁), and delayed (PLGA₂). One 10-mg delivery system was implanted in each rat and an ELISA technique was used to determine the amount of rhNGF in 1-mm coronal brain slices produced immediately after removal of the delivery system. High levels of rhNGF (as high as 60,000 ng in a brain slice of 50 L) were recovered from the brain tissue at 1,2, and 4 weeks after implantation. With all three delivery systems, the amount of rhNGF in each brain slice decreased exponentially with distance from the implant site; the distance over which concentration decreased by 10-fold was 2–3 mm for all delivery systems. When rhNGF release was moderate (10 to 200 ng rhNGF/ day), the total amount of rhNGF in the brain increased linearly with release rate, suggesting an overall rate of rhNGF elimination of 0.4 hr^–1 or a half-life of 1.7 hr. With higher release rates (500 to 50,000 ng rhNGF/day), total amounts of rhNGF in the brain were considerably higher than anticipated based on this rate of elimination. Conclusions. Polymeric controlled release can provide high, localized doses of rhNGF in the brain. All of the experimental data were consistent with penetration of rhNGF through the brain tissue with a diffusion coefficient 8 X 10^–7 cm²/s, which is 50% of the diffusion coefficient in water.     

Sustained Vascular Endothelial Growth Factor Delivery Enhances Angiogenesis and Perfusion in Ischemic Hind Limb

Purpose We hypothesized that sustained delivery of vascular endothelial growth factor (VEGF) using a polymer [85:15 poly(lactide-co-glycolide) (PLG)] would enhance angiogenesis and improve perfusion of ischemic tissue.Methods C57BL/6J mice (n = 20/group) underwent unilateral hind limb ischemia surgery and were randomized to groups of no scaffold implantation (∅-Implant), unloaded scaffold implantation (Empty-PLG), or implantation of scaffolds incorporating 3 μg of VEGF₁₆₅ (PLG-VEGF). Endpoints included laser Doppler perfusion imaging (LDPI, ischemic/nonischemic limb, %), local vessel counts, immunohistochemistry for CD31, and α-smooth muscle actin. In vitro release kinetics of VEGF from PLG was also measured.Results PLG-VEGF resulted in improved lower extremity perfusion vs. controls as measured by LDPI% at 7, 14, 21, and 28 days (p < 0.05). PLG-VEGF was associated with significantly greater percentage of vessels staining for CD31 and α-smooth muscle actin compared to the Empty-PLG or ∅-Implant (p < 0.05 for both).Conclusions The PLG-VEGF scaffolds resulted in sustained VEGF delivery, improved tissue perfusion, greater capillary density, and more mature vasculature compared to the controls. The sustained-release PLG polymer vehicle is a promising delivery system for therapeutic neovascularization applications.     

鼠神经生长因子在特发性面神经麻痹的疗效观察

目的观察鼠神经生长因子在特发性面神经麻痹的疗效。方法将60例患者分成2组,治疗组和对照组。其中对照组使用激素、B族维生素、针灸理疗等常规治疗;治疗组则在常规治疗基础上,加用鼠神经生长因子,采用House-Brackmamn面神经功能分级评定及临床疗效指标评定。结果治疗组治愈率40%,总有效率93.3%。对照组治愈率30%,总有效率90%。治疗组明显优于对照组,二者差异有统计学意义(P<0.05)。结论鼠神经生长因子在治疗特发性面神经麻痹有效。     

冠心病患者无症状心肌缺血的动态心电图分析

本文对103例冠心病患者其中68例无症状心肌缺血进行24小时动态心电图分析,监测结果,陈旧性心肌梗塞和冠心病心绞痛两组无症状ST段压低均高于有症状(P<0.05),但两组之间有症状与无症状发生率无显著差异。68例无症状心肌缺血中有64例ST段压低均发生于日常活动和卧床休息时。发作时间以6～12点最多,缺血严重程度及时限与症状无关。