Gene transfer to skeletal muscle using hydrodynamic limb vein injection: current applications,hurdles and possible optimizations

Hydrodynamic limb vein injection is an in vivo locoregional gene delivery method. It consists of administrating a large volume of solution containing nucleic acid constructs in a limb with both blood inflow and outflow temporarily blocked using a tourniquet. The fast, high pressure delivery allows the musculature of the whole limb to be reached. The skeletal muscle is a tissue of choice for a variety of gene transfer applications, including gene therapy for Duchenne muscular dystrophy or other myopathies, as well as for the production of antibodies or other proteins with broad therapeutic effects. Hydrodynamic limb vein delivery has been evaluated with success in a large range of animal models. It has also proven to be safe and well‐tolerated in muscular dystrophy patients, thus supporting its translation to the clinic. However, some possible limitations may occur at different steps of the delivery process. Here, we have highlighted the interests, bottlenecks and potential improvements that could further optimize non‐viral gene transfer following hydrodynamic limb vein injection.     

Drug-delivering nerve conduit improves regeneration in a critical-sized gap

Autologous nerve grafts are the current “gold standard” for repairing large nerve gaps. However, they cause morbidity at the donor nerve site and only a limited amount of nerve can be harvested. Nerve conduits are a promising alternative to autografts and can act as guidance cues for the regenerating axons, without the need to harvest donor nerve. Separately, it has been shown that localized delivery of GDNF can enhance axon growth and motor recovery. FK506, an FDA approved small molecule, has also been shown to enhance peripheral nerve regeneration. This paper describes the design of a novel hole-based drug delivery apparatus integrated with a polytetrafluoroethylene (PTFE) nerve conduit for controlled local delivery of a protein such as GDNF or a small molecule such as FK506. The PTFE devices were tested in a diffusion chamber, and the bioactivity of the released media was evaluated by measuring neurite growth of dorsal root ganglions (DRGs) exposed to the released drugs. The drug delivering nerve guide was able to release bioactive concentrations of FK506 or GDNF. Following these tests, optimized drug releasing nerve conduits were implanted across 10 mm sciatic nerve gaps in a BL6 yellow fluorescent protein (YFP) mouse model, where they demonstrated significant improvement in muscle mass, compound muscle action potential, and axon myelination in vivo as compared with nerve conduits without the drug. The drug delivery nerve guide could release drug for extended periods of time and enhance axon growth in vitro and in vivo.     

pH-Dependent Effects of Chlorpromazine on Liposomes and Erythrocyte Membranes

Abstract

Chlorpromazine (CPZ) is an amphipathic antipsychotic drug that binds to erythrocytes reaching in this way the central nervous system. CPZ is a basic molecule with pK = 8.6. This paper reports on CPZ-induced lysis of red blood cells and liposomes. Haemolysis was tested under hypotonic conditions, in the pH range 5.0–10.0. Cell sensitivity towards CPZ increased with increasing pH. Increasing pH caused also a decrease in the critical micellar concentrations of CPZ. These results are interpreted in terms of a competition between repulsive electrostatic forces and attractive hydrophobic forces, that would act both in pure CPZ and in mixed CPZ-phospholipid micelles. In order to eliminate possible pH effects mediated by red blood cell proteins, experiments were carried out in which CPZ induced release of a fluorescent dye from liposomes (large unilamellar vesicles). The latter observations confirmed that membrane sensitivity towards CPZ was increased at higher pH.     

A single dose of recombinant Salmonella typhimurium induces specific humoral immune responses against heterologous Eimeria tenella antigens in chicken

Salmonella typhimurium vaccine strains were used as antigen delivery system for oral immunisation of chickens against two antigens of the coccidian parasite Eimeria tenella. The cDNAs of the known E. tenella proteins, SO7 and TA4, were isolated from total RNA and subcloned into the expression vectors pQE30 and pTECH2. Subcutaneous immunisation of chickens with Escherichia coli-expressed SO7 and TA4 revealed that both proteins were immunogenic. Both cDNAs were subcloned into plasmids of the pTECH2 vector system, which allows them to be expressed as fusion proteins with the highly immunogenic fragment C of the tetanus toxin under control of the anaerobically inducible nirB promoter. Plasmids were introduced into the S. typhimurium vaccine strains SL3261, C5aroD and C5htrA. SDS-PAGE and Western blot analysis revealed expression of both fusion proteins in all strains under anaerobic culture conditions. Three-week-old white leghorn chickens were orally immunised with 10(9) CFU per animal. The stability of the recombinant bacteria was revealed by recovery of viable Salmonella containing the respective plasmids from the liver of the immunised chickens at day 3 after inoculation. Specific serum IgG antibodies against the SO7-or TA4-antigens were detectable by ELISA 2 weeks after oral immunisation and remained for at least 6 weeks, while specific IgA antibodies were restricted to the bile of the birds. All chickens produced serum IgG and IgA to S. typhimurium lipopolysaccharides. Our data show that a single oral inoculation with recombinant S. typhimurium SL3261, C5aroD and C5htrA can induce specific antibody responses to heterologous Eimeria antigens in chickens, suggesting that recombinant Salmonella are a suitable delivery system for vaccines against Eimeria infections.     

丙泊酚应用于无痛人工流产800例分析

目的:探讨丙泊酚在无痛人工流产术中的应用效果.方法:将886例早孕未产妇女和/或有剖宫产史妊娠妇女分为试验组和对照组,试验组800例,对照组86例.不采取镇痛麻醉的86例为对照组,试验组对人工流产病人施行丙泊酚静脉全身麻醉,并静脉给阿托品,其余操作同对照组.观察比较两组术中反应、手术时间、出血量与人工流产综合征的发生情况.结果:试验组病人无痛苦,舒适满意,手术时间明显缩短,无一例发生人工流产综合征.对照组69例(80.2%)诉疼痛难忍,11例(12.8)诉下腹痛但可以忍受,6例患者(7.0%)完全不痛.结论:丙泊酚具有高效,显效快速和安全的特点,静脉给丙泊酚可防止人工流产综合征的发生.     

Cyclization of a cell‐penetrating peptide via click‐chemistry increases proteolytic resistance and improves drug delivery

In this work we report synthesis and biological evaluation of a cell‐penetrating peptide (CPP), that is partly cyclized via a triazole bridge. Recently, beneficious properties have been reported for cyclized peptides concerning their metabolic stability and intracellular uptake. A CPP based on human calcitonin was used in this study, and side chain cyclization was achieved via copper catalyzed alkyne‐azide click reaction. Cell viability studies in several cell‐lines revealed no cytotoxic effects. Furthermore, efficient uptake in breast cancer MCF‐7 cells could be determined. Moreover, preliminary studies using this novel peptide as drug transporter for daunorubicin were performed. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

Engineered magnetic core shell nanoprobes:Synthesis and applications to cancer imaging and therapeutics

Magnetic core shell nanoparticles are composed of a highly magnetic core material surrounded by a thin shell of desired drug, polymer or metal oxide. These magnetic core shell nanoparticles have a wide range of applications in biomedical research, more specifically in tissue imaging, drug delivery and therapeutics. The present review discusses the up-to-date knowledge on the various procedures for synthesis of magnetic core shell nanoparticles along with their applications in cancer imaging, drug delivery and hyperthermia or cancer therapeutics. Literature in this area shows that magnetic core shell nanoparticle-based imaging, drug targeting and therapy through hyperthermia can potentially be a powerful tool for the advanced diagnosis and treatment of various cancers.     

生物可降解嵌段共聚物在给药载体中的应用

生物可降解嵌段聚合物因具有双亲性 ,靶向药物到特定部位等优点大大推动了作为给药载体系统的发展。本文综述了生物可降解嵌段聚合物在表面修饰、水凝胶、胶束、生物大分子载体系统中的应用