Novel Focused Ultrasound Gene Therapy Approach Noninvasively Restores Dopaminergic Neuron Function in a Rat Parkinson's Disease Model.

Therapies capable of decelerating, or perhaps even halting, neurodegeneration in Parkinson's disease (PD) remain elusive. Clinical trials of PD gene therapy testing the delivery of neurotrophic factors, such as the glial cell-line derived neurotrophic factor (GDNF), have been largely ineffective due to poor vector distribution throughout the diseased regions in the brain. In addition, current delivery strategies involve invasive procedures that obviate the inclusion of early stage patients who are most likely to benefit from GDNF-based gene therapy. Here, we introduce a two-pronged treatment strategy, composed of MR image-guided focused ultrasound (FUS) and brain-penetrating nanoparticles (BPN), that provides widespread but targeted GDNF transgene expression in the brain following systemic administration. MR image-guided FUS allows circulating gene vectors to partition into the brain tissue by noninvasive and transient opening of the blood-brain barrier (BBB) within the areas where FUS is applied. Once beyond the BBB, BPN provide widespread and uniform GDNF expression throughout the targeted brain tissue. After only a single treatment, our strategy led to therapeutically relevant levels of GDNF protein content in the FUS-targeted regions in the striatum of the 6-OHDA-induced rat model of PD, which lasted at least up to 10 weeks. Importantly, our strategy restored both dopamine levels and dopaminergic neuron density and reversed behavioral indicators of PD-associated motor dysfunction with no evidence of local or systemic toxicity. Our combinatorial approach overcomes limitations of current delivery strategies, thereby potentially providing a novel means to treat PD.

Effect of conversion from ESA with shorter half-life to CERA once monthly for maintaining Hb concentration in pre-dialysis CKD patients.

BACKGROUND: The purpose of this study is to identify whether hemoglobin (Hb) concentrations can be maintained, and to investigate changes in biomarkers, when switching from erythropoietin stimulating agents (ESA) with shorter half-life to once-monthly subcutaneous methoxy polyethylene glycol-epoetin ß (CERA) in pre-dialysis chronic kidney disease (CKD) patients. METHODS: Pre-dialysis CKD patients (n=191) aged ≥18 years who maintained their Hb level 10-12 g/dL through use of epoetin-α, epoetin-ß, or darbepoetin-α were enrolled. Hb levels and CERA dose was assessed prospectively for 24 weeks. Serum biomarkers related to coagulation, endothelial function, and iron metabolism were measured at weeks 0 and 24. RESULTS: Baseline Hb concentration was 10.8±0.6 g/dL Twelve and 24 weeks after conversion, mean Hb levels were 11.9±0.9 and 11.2±0.9 g/dL, respectively. The mean monthly CERA dose required to maintain Hb levels was gradually reduced. Of total 387 dose adjustments, dose increases and decreases occurred in 35 (9.0%) and 352 (91.0%) episodes, respectively. Hb overshoot occurred in 14 (9.7%) patients. P-selectin was significantly decreased, whereas VCAM was significantly increased 24 weeks after conversion (P < 0.05). Serum soluble transferrin receptor E-selectin and prohepcidin levels were similar before and after switching to CERA (P=N-S). CONCLUSION: Conversion from ESA with shorter half-life to subcutaneous once-monthly CERA in pre-dialysis CKD patients can efficaciously maintain Hb. The CERA dose requirement decreased significantly. The conversion ratio may need to be reduced when switching from ESA with shorter half-life to CERA. CERA may change biomarkers associated with platelet reactivity and endothelial microenvironment.

PEGylated enhanced cell penetrating peptide nanoparticles for lung gene therapy.

The lung remains an attractive target for the gene therapy of monogenetic diseases such as cystic fibrosis (CF). Despite over 27 clinical trials, there are still very few gene therapy vectors that have shown any improvement in lung function; highlighting the need to develop formulations with improved gene transfer potency and the desirable physiochemical characteristics for efficacious therapy. Herein, we introduce a novel cell penetrating peptide (CPP)-based non-viral vector that utilises glycosaminoglycan (GAG)-binding enhanced transduction (GET) for highly efficient gene transfer. GET peptides couple directly with DNA through electrostatic interactions to form nanoparticles (NPs). In order to adapt the GET peptide for efficient in vivo delivery, we engineered PEGylated versions of the peptide and employed a strategy to form DNA NPs with different densities of PEG coatings. We were able to identify candidate formulations (PEGylation rates ≥40%) that shielded the positively charged surface of particles, maintained colloidal stability in bronchoalveolar lavage fluid (BALF) and retained gene transfer activity in human bronchial epithelial cell lines and precision cut lung slices (PCLS) in vitro. Using multiple particle tracking (MPT) technology, we demonstrated that PEG-GET complexes were able to navigate the mucus mesh and diffuse rapidly through patient CF sputum samples ex vivo. When tested in mouse lung models in vivo, PEGylated particles demonstrated superior biodistribution, improved safety profiles and efficient gene transfer of a reporter luciferase plasmid compared to non-PEGylated complexes. Furthermore, gene expression was significantly enhanced in comparison to polyethylenimine (PEI), a non-viral gene carrier that has been widely tested in pre-clinical settings. This work describes an innovative approach that combines novel GET peptides for enhanced transfection with a tuneable PEG coating for efficacious lung gene therapy.

PEGylation as a strategy for improving nanoparticle-based drug and gene delivery.

Coating the surface of nanoparticles with polyethylene glycol (PEG), or "PEGylation", is a commonly used approach for improving the efficiency of drug and gene delivery to target cells and tissues. Building from the success of PEGylating proteins to improve systemic circulation time and decrease immunogenicity, the impact of PEG coatings on the fate of systemically administered nanoparticle formulations has, and continues to be, widely studied. PEG coatings on nanoparticles shield the surface from aggregation, opsonization, and phagocytosis, prolonging systemic circulation time. Here, we briefly describe the history of the development of PEGylated nanoparticle formulations for systemic administration, including how factors such as PEG molecular weight, PEG surface density, nanoparticle core properties, and repeated administration impact circulation time. A less frequently discussed topic, we then describe how PEG coatings on nanoparticles have also been utilized for overcoming various biological barriers to efficient drug and gene delivery associated with other modes of administration, ranging from gastrointestinal to ocular. Finally, we describe both methods for PEGylating nanoparticles and methods for characterizing PEG surface density, a key factor in the effectiveness of the PEG surface coating for improving drug and gene delivery.

Reducible Polyethylenimine Nanoparticles for Efficient siRNA Delivery in Corneal Neovascularization Therapy.

The aim of this study is to establish the safe and effective ocular delivery system of therapeutic small interfering RNA (siRNA) in corneal neovascularization therapy. The major hurdle present in siRNA-based corneal neovascularization (CNV) therapy is severe cytotoxicity caused by repetitive drug treatment. A reducible branched polyethylenimine (rBPEI)-based nanoparticle (NP) system is utilized as a new siRNA carrier as a hope for CNV therapy. The thiolated BPEI is readily self-crosslinked in mild conditions to make high molecular weight rBPEI thus allowing the creation of stable siRNA/rBPEI nanoparticles (siRNA-rBPEI-NPs). In the therapeutic region, the rBPEI polymeric matrix is effectively degraded into nontoxic LMW BPEI inside the reductive cytosol causing the rapid release of the encapsulated siRNA into the cytosol to carry out its function. The fluorescent-labeled siRNA-rBPEI-NPs can release siRNA into the entire corneal region after subconjuctival injection into the eye of Sprague Dawley rats thus confirming the proof of concept of this system.

Effects of rhBMP-2 on Sandblasted and Acid Etched Titanium Implant Surfaces on Bone Regeneration and Osseointegration: Spilt-Mouth Designed Pilot Study.

This study was conducted to evaluate effects of rhBMP-2 applied at different concentrations to sandblasted and acid etched (SLA) implants on osseointegration and bone regeneration in a bone defect of beagle dogs as pilot study using split-mouth design. Methods. For experimental groups, SLA implants were coated with different concentrations of rhBMP-2 (0.1, 0.5, and 1 mg/mL). After assessment of surface characteristics and rhBMP-2 releasing profile, the experimental groups and untreated control groups (n = 6 in each group, two animals in each group) were placed in split-mouth designed animal models with buccal open defect. At 8 weeks after implant placement, implant stability quotients (ISQ) values were recorded and vertical bone height (VBH, mm), bone-to-implant contact ratio (BIC, %), and bone volume (BV, %) in the upper 3 mm defect areas were measured. Results. The ISQ values were highest in the 1.0 group. Mean values of VBH (mm), BIC (%), and BV (%) were greater in the 0.5 mg/mL and 1.0 mg/mL groups than those in 0.1 and control groups in buccal defect areas. Conclusion. In the open defect area surrounding the SLA implant, coating with 0.5 and 1.0 mg/mL concentrations of rhBMP-2 was more effective, compared with untreated group, in promoting bone regeneration and osseointegration.

Comparison of the impact of high-flux dialysis on mortality in hemodialysis patients with and without residual renal function.

BACKGROUND: The effect of flux membranes on mortality in hemodialysis (HD) patients is controversial. Residual renal function (RRF) has shown to not only be as a predictor of mortality but also a contributor to ß2-microglobulin clearance in HD patients. Our study aimed to determine the interaction of residual renal function with dialyzer membrane flux on mortality in HD patients. METHODS: HD Patients were included from the Clinical Research Center registry for End Stage Renal Disease, a prospective observational cohort study in Korea. Cox proportional hazards regression models were used to study the association between use of high-flux dialysis membranes and all-cause mortality with RRF and without RRF. The primary outcome was all-cause mortality. RESULTS: This study included 893 patients with 24 h-residual urine volume ≥100 ml (569 and 324 dialyzed using low-flux and high-flux dialysis membranes, respectively) and 913 patients with 24 h-residual urine volume <100 ml (570 and 343 dialyzed using low-flux and high-flux dialysis membranes, respectively). After a median follow-up period of 31 months, mortality was not significantly different between the high and low-flux groups in patients with 24 h-residual urine volume ≥100 ml (HR 0.86, 95% CI, 0.38-1.95, P = 0.723). In patients with 24 h-residual urine volume <100 ml, HD using high-flux dialysis membrane was associated with decreased mortality compared to HD using low-flux dialysis membrane in multivariate analysis (HR 0.40, 95% CI, 0.21-0.78, P = 0.007). CONCLUSIONS: Our data showed that HD using high-flux dialysis membranes had a survival benefit in patients with 24 h-residual urine volume <100 ml, but not in patients with 24 h-residual urine volume ≥100 ml. These findings suggest that high-flux dialysis rather than low-flux dialysis might be considered in HD patients without RRF.

The use of botulinum toxin type A in aesthetic mandibular contouring.

The lower third of Asian faces is wider than that of Caucasians and it is determined by the size and width of the mandibular bone and the thickness of muscles and subcutaneous fat tissues surrounding it. Efforts to create an aesthetically slim and smooth facial contour line in nonobese people have led the authors to focus on two approaches: surgical resection of the masseteric muscle and modeling ostectomy of the square-angled mandibular bone. Because these procedures present some problems, the authors adopted a nonsurgical concept that chemically denervates muscles and reduces the bulk of the muscle. The authors have conducted a total of 1021 clinical cases from March of 2001 through September of 2002, in which patients were treated with botulinum toxin type A (Dysport; Ipsen Ltd, Slough, United Kingdom) for remodeling the lower facial contour line; 383 of those cases were followed up for at least 3 months after the initial injection. A database was made by measuring the change in the thickness of the injected muscle with an ultrasonogram. Eleven patients underwent resection of the mandibular angle before injection. The preinjection ostectomy group was involved in the study as a result of their dissatisfaction with the surgical results; they had a rather thick masseter muscle and not a bone problem. Some had both bone problems and a thick masseter muscle. Three months after the botulinum toxin injection, the thickness of the muscle was reduced by 31 percent on average. The atrophic effect of injection was observed after 2 to 4 weeks for most patients. Seventy percent of the 383 patients tracked were greatly satisfied with the result, with another 23 percent generally satisfied. No long-term side effects were reported. Masseteric hypertrophy is frequent in Asians because of racial characteristics and dietary habits. Botulinum toxin type A has made a new epoch in facial contouring for Asians. Considering that Asians have a prominent malar and a prominent mandible angle, the reduction in the thickness of the masseter can provoke relative prominence of the malar and mandible angle. Therefore, precise indication and anatomy of the facial muscle should be thoroughly understood, which will decrease the incidence of side effects and problems. Botulinum toxin type A (Dysport) injection is simple in technique, has few side effects, and promises a rapid return to daily life. The authors conclude that the injection of botulinum toxin type A can replace surgical masseter resection.