Engineered Exosomes Containing microRNA-29b-2 and Targeting the Somatostatin Receptor Reduce Presenilin 1 Expression and Decrease the ß-Amyloid Accumulation in the Brains of Mice with Alzheimer's Disease.

Purpose: Exosomes are membrane vesicles secreted by various cells and play a crucial role in intercellular communication. They can be excellent delivery vehicles for oligonucleotide drugs, such as microRNAs, due to their high biocompatibility. MicroRNAs have been shown to be more stable when incorporated into exosomes; however, the lack of targeting and immune evasion is still the obstacle to the use of these microRNA-containing nanocarriers in clinical settings. Our goal was to produce functional exosomes loaded with target ligands, immune evasion ligand, and oligonucleotide drug through genetic engineering in order to achieve more precise medical effects. Methods: To address the problem, we designed engineered exosomes with exogenous cholecystokinin (CCK) or somatostatin (SST) as the targeting ligand to direct the exosomes to the brain, as well as transduced CD47 proteins to reduce the elimination or phagocytosis of the targeted exosomes. MicroRNA-29b-2 was the tested oligonucleotide drug for delivery because our previous research showed that this type of microRNA was capable of reducing presenilin 1 (PSEN1) gene expression and decreasing the ß-amyloid accumulation for Alzheimer's disease (AD) in vitro and in vivo. Results: The engineered exosomes, containing miR29b-2 and expressing SST and CD47, were produced by gene-modified dendritic cells and used in the subsequent experiments. In comparison with CD47-CCK exosomes, CD47-SST exosomes showed a more significant increase in delivery efficiency. In addition, CD47-SST exosomes led to a higher delivery level of exosomes to the brains of nude mice when administered intravenously. Moreover, it was found that the miR29b-2-loaded CD47-SST exosomes could effectively reduce PSEN1 in translational levels, which resulted in an inhibition of beta-amyloid oligomers production both in the cell model and in the 3xTg-AD animal model. Conclusion: Our results demonstrated the feasibility of the designed engineered exosomes. The application of this exosomal nanocarrier platform can be extended to the delivery of other oligonucleotide drugs to specific tissues for the treatment of diseases while evading the immune system.

Liposome Consolidated with Cyclodextrin Provides Prolonged Drug Retention Resulting in Increased Drug Bioavailability in Brain.

Although butylidenephthalide (BP) is an efficient anticancer drug, its poor bioavailability renders it ineffective for treating drug-resistant brain tumors. However, this problem is overcome through the use of noninvasive delivery systems, including intranasal administration. Herein, the bioavailability, drug stability, and encapsulation efficiency (EE, up to 95%) of BP were improved by using cyclodextrin-encapsulated BP in liposomal formulations (CDD1). The physical properties and EE of the CDD1 system were investigated via dynamic light scattering, transmission electron microscopy, UV-Vis spectroscopy, and nuclear magnetic resonance spectroscopy. The cytotoxicity was examined via MTT assay, and the cellular uptake was observed using fluorescence microscopy. The CDD1 system persisted for over 8 h in tumor cells, which was a considerable improvement in the retention of the BP-containing cyclodextrin or the BP-containing liposomes, thereby indicating a higher BP content in CDD1. Nanoscale CDD1 formulations were administered intranasally to nude mice that had been intracranially implanted with temozolomide-resistant glioblastoma multiforme cells, resulting in increased median survival time. Liquid chromatography-mass spectrometry revealed that drug biodistribution via intranasal delivery increased the accumulation of BP 10-fold compared to oral delivery methods. Therefore, BP/cyclodextrin/liposomal formulations have potential clinical applications for treating drug-resistant brain tumors.

Exosomes in clinical trial and their production in compliance with good manufacturing practice.

Exosomes, 60-200-nm extracellular vesicles secreted from cells, have been used as an active pharmaceutical ingredient or drug carrier in disease treatment. Human- and plant-derived exosomes are registered in clinical trials, but more complete reports are available for human-derived exosomes. Because exosomes act as vesicles and carry cell secreting components, they have been used as drug or peptide vehicles to treat diseases. The dendritic cells (DCs) and mesenchymal stem cells (MSCs) are two popular cell sources for exosome preparation. Exosomes from DCs can initiate inflammation in patients, particularly in patients with cancer, as they contain the tumor antigen to induce specific inflammation response. A well-established cell bank of MSCs is available, and these cells can be used as an alternative source for exosome preparation. The major application of MSC-derived exosomes is in inflammation treatment. Exosomes in clinical trials need to comply with good manufacturing practice (GMP). Three important issues are prevalent in GMP for exosomes, i.e., upstream of cell cultivation process, downstream of the purification process, and exosome quality control. This paper concisely reviews exosome development, including exosome generation and clinical trial application.

Integration of PEG 400 into a self-nanoemulsifying drug delivery system improves drug loading capacity and nasal mucosa permeability and prolongs the survival of rats with malignant brain tumors.

Introduction: Kolliphor® EL (K-EL) is among the most useful surfactants in the preparation of emulsions. However, it is associated with low hydrophobic drug loading in the resulting emulsified formulation. Methods: In this study, a formulation for intranasal administration of butylidenephthalide (Bdph), a candidate drug against glioblastoma (GBM), was prepared. Physical characteristics of the formulation such as particle size, zeta potential, conductivity, and viscosity were assessed, as well as its cytotoxicity and permeability, in order to optimize the formulation and improve its drug loading capacity. Results: The optimized formulation involved the integration of polyethylene glycol 400 (PEG 400) in K-EL to encapsulate Bdph dissolved in dimethyl sulfoxide (DMSO), and it exhibited higher drug loading capacity and drug solubility in water than the old formulation, which did not contain PEG 400. Incorporation of PEG 400 as a co-surfactant increased Bdph loading capacity to up to 50% (v/v), even in formulations using Kolliphor® HS 15 (K-HS15) as a surfactant, which is less compatible with Bdph than K-EL. The optimized Bdph formulation presented 5- and 2.5-fold higher permeability and cytotoxicity, respectively, in human GBM than stock Bdph. This could be attributed to the high drug loading capacity and the high polarity index due to DMSO, which increases the compatibility between the drug and the cell. Rats bearing a brain glioma treated with 160 mg/kg intranasal emulsified Bdph had a mean survival of 37 days, which is the same survival time achieved by treatment with 320 mg/kg stock Bdph. This implies that the optimized emulsified formulation required only half the Bdph dose to achieve an efficacy similar to that of stock Bdph in the treatment of animals with malignant brain tumor.

Social and built-environment factors related to children's independent mobility: The importance of neighbourhood cohesion and connectedness.

This study examines aspects of neighbourhood social environments (namely, neighbourhood safety, cohesion and connection) and child-specific built environment attributes in relation to children's independent mobility. The results suggest that children aged 8-13 years with parents who perceive their neighbourhood as more cohesive and more connected, and are located closer to school, engaged in higher levels of independently mobile trips. The qualitative component of this research revealed that for NZ European, Maori, Samoan and other Pacific parents, 'people danger' was the most common concern for letting their children go out alone, whereas for Asian and Indian parents, 'traffic danger' was the most common reason for their concern.

Associations between the neighbourhood built environment and out of school physical activity and active travel: An examination from the Kids in the City study.

This study's aim was to examine selected objectively-measured and child specific built environment attributes in relation to proportion of out-of-school time spent in moderate-to-vigorous physical activity (%MVPA) and active travel in a group of ethnically and socio-economically diverse children (n=236) living in Auckland, New Zealand. Street connectivity and distance to school were related to the proportion of trips made by active modes. Ratio of high speed to low speed roads and improved streetscape for active travel were related to %MVPA on weekdays only. Inconsistent results were found for destination accessibility. Local destinations (particularly schools) along a safe street network may be important for encouraging children's activity behaviours.

Neighbourhood matters: perceptions of neighbourhood cohesiveness and associations with alcohol, cannabis and tobacco use.

INTRODUCTION AND AIMS: To examine relationships between perceived neighbourhood cohesion and alcohol, tobacco and cannabis consumption in New Zealand. DESIGN AND METHODS: A two-level random intercept regression model was used to examine the extent to which perception of neighbourhood cohesion (at the individual and area level) was associated with the frequency of substance (alcohol, tobacco and cannabis) consumption, after controlling for demographics and deprivation. This study is based on data from two national Health Behaviours Surveys (Drugs and Alcohol) conducted in 2003 and 2004 in New Zealand. Data were collected by computer-assisted telephone interviewing with two complementary computer-assisted cellphone interviewing samples. The combined sample consists of 6346 men and 8411 women (n = 14,757) distributed across 1572 census area units. RESULTS: Perception of neighbourhood cohesion was significantly associated with the level of alcohol, tobacco and cannabis consumption. Individuals who perceived their neighbourhood as more cohesive had higher annual frequency of alcohol consumption but lower consumption on a typical drinking occasion. Higher perceived neighbourhood cohesion was also associated with a decrease in the probability of tobacco and cannabis use and of the amounts consumed. Area-level analysis suggested that aggregate census area unit-level neighbourhood cohesion exerted a significant additional contextual effect on the frequency of tobacco and cannabis consumption over and above individual perceptions of neighbourhood cohesiveness. DISCUSSION AND CONCLUSIONS: This study provides empirical evidence that perceptions of the neighbourhood social environment are associated with people's substance consumption patterns. Increasing residents' sense of neighbourhood cohesion might prove a promising way to decrease health-damaging consumption behaviours.

Kids in the city study: research design and methodology.

BACKGROUND: Physical activity is essential for optimal physical and psychological health but substantial declines in children's activity levels have occurred in New Zealand and internationally. Children's independent mobility (i.e., outdoor play and traveling to destinations unsupervised), an integral component of physical activity in childhood, has also declined radically in recent decades. Safety-conscious parenting practices, car reliance and auto-centric urban design have converged to produce children living increasingly sedentary lives. This research investigates how urban neighborhood environments can support or enable or restrict children's independent mobility, thereby influencing physical activity accumulation and participation in daily life. METHODS/DESIGN: The study is located in six Auckland, New Zealand neighborhoods, diverse in terms of urban design attributes, particularly residential density. Participants comprise 160 children aged 9-11 years and their parents/caregivers. Objective measures (global positioning systems, accelerometers, geographical information systems, observational audits) assessed children's independent mobility and physical activity, neighborhood infrastructure, and streetscape attributes. Parent and child neighborhood perceptions and experiences were assessed using qualitative research methods. DISCUSSION: This study is one of the first internationally to examine the association of specific urban design attributes with child independent mobility. Using robust, appropriate, and best practice objective measures, this study provides robust epidemiological information regarding the relationships between the built environment and health outcomes for this population.