Design Considerations for Intratracheal Delivery Devices to Achieve Proof-of-Concept Dry Powder Biopharmaceutical Delivery in Mice.

PURPOSE: Intratracheal delivery and consistent dosing of dry powder vaccines is especially challenging in mice. To address this issue, device design of positive pressure dosators and actuation parameters were assessed for their impacts on powder flowability and in vivo dry powder delivery. METHODS: A chamber-loading dosator assembled with stainless-steel, polypropylene or polytetrafluoroethylene needle-tips was used to determine optimal actuation parameters. Powder loading methods including tamp-loading, chamber-loading and pipette tip-loading were compared to assess performance of the dosator delivery device in mice. RESULTS: Available dose was highest (45%) with a stainless-steel tip loaded with an optimal mass and syringe air volume, primarily due to the ability of this configuration to dissipate static charge. However, this tip encouraged more agglomeration along its flow path in the presence of humidity and was too rigid for intubation of mice compared to a more flexible polypropylene tip. Using optimized actuation parameters, the polypropylene pipette tip-loading dosator achieved an acceptable in vivo emitted dose of 50% in mice. After administering two doses of a spray dried adenovirus encapsulated in mannitol-dextran, high bioactivity was observed in excised mouse lung tissue three days post-infection. CONCLUSIONS: This proof-of-concept study demonstrates for the first time that intratracheal delivery of a thermally stable, viral-vectored dry powder can achieve equivalent bioactivity to the same powder, reconstituted and delivered intratracheally. This work may guide the design and device selection process for murine intratracheal delivery of dry powder vaccines to help progress this promising area of inhalable therapeutics.

Corrigendum: Differential biodistribution of adenoviral-vectored vaccine following intranasal and endotracheal deliveries leads to different immune outcomes.

[This corrects the article DOI: 10.3389/fimmu.2022.860399.].

Dextran Mass Ratio Controls Particle Drying Dynamics in a Thermally Stable Dry Powder Vaccine for Pulmonary Delivery.

PURPOSE: Thermally stable, spray dried vaccines targeting respiratory diseases are promising candidates for pulmonary delivery, requiring careful excipient formulation to effectively encapsulate and protect labile biologics. This study investigates the impact of dextran mass ratio and molecular weight on activity retention, thermal stability and aerosol behaviour of a labile adenoviral vector (AdHu5) encapsulated within a spray dried mannitol-dextran blend. METHODS: Comparing formulations using 40 kDa or 500 kDa dextran at mass ratios of 1:3 and 3:1 mannitol to dextran, in vitro quantification of activity losses and powder flowability was used to assess suitability for inhalation. RESULTS: Incorporating mannitol in a 1:3 ratio with 500 kDa dextran reduced viral titre processing losses below 0.5 log and displayed strong thermal stability under accelerated aging conditions. Moisture absorption and agglomeration was higher in dextran-rich formulations, but under low humidity the 1:3 ratio with 500 kDa dextran powder had the lowest mass median aerodynamic diameter (4.4 µm) and 84% emitted dose from an intratracheal dosator, indicating strong aerosol performance. CONCLUSIONS: Overall, dextran-rich formulations increased viscosity during drying which slowed self-diffusion and favorably hindered viral partitioning at the particle surface. Reducing mannitol content also minimized AdHu5 exclusion from crystalline regions that can force the vector to air-solid interfaces where deactivation occurs. Although increased dextran molecular weight improved activity retention at the 1:3 ratio, it was less influential than the ratio parameter. Improving encapsulation ultimately allows inhalable vaccines to be prepared at higher potency, requiring less powder mass per inhaled dose and higher delivery efficiency.

Differential Biodistribution of Adenoviral-Vectored Vaccine Following Intranasal and Endotracheal Deliveries Leads to Different Immune Outcomes.

Infectious diseases of the respiratory tract are one of the top causes of global morbidity and mortality with lower respiratory tract infections being the fourth leading cause of death. The respiratory mucosal (RM) route of vaccine delivery represents a promising strategy against respiratory infections. Although both intranasal and inhaled aerosol methods have been established for human application, there is a considerable knowledge gap in the relationship of vaccine biodistribution to immune efficacy in the lung. Here, by using a murine model and an adenovirus-vectored model vaccine, we have compared the intranasal and endotracheal delivery methods in their biodistribution, immunogenicity and protective efficacy. We find that compared to intranasal delivery, the deepened and widened biodistribution in the lung following endotracheal delivery is associated with much improved vaccine-mediated immunogenicity and protection against the target pathogen. Our findings thus support further development of inhaled aerosol delivery of vaccines over intranasal delivery for human application.

Cryoprotective agents influence viral dosage and thermal stability of inhalable dry powder vaccines.

Increasing viral dosage within dry powder vaccines reduces the powder mass required to elicit an immune response through pulmonary delivery. This work analyzes how cryoprotective agents affect viral activity, particle properties and thermal stability of a spray dried, inhalable vaccine vector under high viral loading. Stock suspensions of a human serotype 5 adenovirus (AdHu5) vector in either neat phosphate buffered saline (PBS), 10% glycerol in PBS, or 5% trehalose in PBS were added to a mannitol-dextran formulation prior to spray drying. At high viral loading, spray dried powder containing glycerol had a viral titre log loss of 2.8 compared to 0.7 log loss using neat PBS. Powders containing glycerol had a lower glass transition temperature (Tg) compared to all other formulations, permitting greater viral mobility and exposure to heat damage. Inclusion of glycerol also promoted particle cohesion during spray drying and lower yields. Using 5% trehalose as a cryogenic alternative, viral powders had a viral log loss of 1.5 and the highest displayed thermal stability over time. Additionally, trehalose-containing powders had smaller particles with lower water moisture content and higher powder yield compared to glycerol-containing powders. These findings demonstrate the importance of cryoprotective agent selection when developing thermostable vaccine powders.

Extracorporeal shockwave therapy combined with multiple drilling and intramedullary drug injection for treating early-stage Femur Head Necrosis: Protocol for a randomized controlled trial.

BACKGROUND: Early diagnosis and treatment of the osteonecrosis of the femoral head (ONFH), a refractory disease, is imperative to prevent femoral head collapse; however, the existing solutions remain controversial. This study assessed the safety and efficacy of extracorporeal shock wave therapy (ESWT) combined with multiple drilling and intramedullary drug injection, a novel cocktail therapy, as a randomized controlled trial (RCT) model to postulate an alternative therapy for patients with early-stage ONFH. METHODS: Femoral head necrosis patients aged 20 to 60 years with stage ARCO I-II were recruited. One hundred twenty eligible participants were randomized into four groups in a 1:1:1:1 ratio: extracorporeal shock wave therapy combined with multiple drilling and intramedullary drug injection (group EMI), extracorporeal shock wave therapy (group E), multiple drilling combined with intramedullary drug injection (group MI), and multiple drilling ("positive" control group; group M). The primary outcomes included effective rate, subchondral collapse rate of the femoral head, lesion size, and grade of bone marrow edema. Secondary outcomes included the Harris Hip Score and the visual analog scale. All outcomes were measured at the screening visit (baseline) and at the planned time intervals during treatment and follow-up, and the efficacy was statistically analyzed according to the intention-to-treat sub-populations and per-protocol sub-populations. OBJECTIVES: To examine the clinical efficacy of ESWT combined with multiple drilling and intramedullary drug injection to provide a safe and more effective method for treating early-stage ONFH. TRIAL REGISTRATION NUMBER: ChiCTR1900020888; Pre-results.

VPS53 Suppresses Malignant Properties in Colorectal Cancer by Inducing the Autophagy Signaling Pathway.

BACKGROUND: Many studies found that VPS53, one of the subunits of the golgi-associated retrograde protein (GARP) complexes, was aberrantly expressed in human diseases. AIM: This study investigated the functions and molecular mechanisms of VPS53 in colorectal cancer (CRC). METHODS: Expression and correlation of Beclin 1 and VPS53 were analyzed by RT-qPCR and Pearson's correlation in CRC tissues, and VPS53 expression was also determined in CRC cells. The changes of proliferation, migration, invasion, apoptosis, and autophagy of CRC cells were examined by a succession of functional experiments including CCK-8, flow cytometry, transwell assay, and electron microscopy. The levels of autophagy related proteins were evaluated by Western blotting analysis. RESULTS: RT-qPCR results found that VPS53 was downregulated in CRC tissues and cells, and Beclin 1 expression was also decreased in CRC tissues. There was a positive correlation between VPS53 and Beclin 1. Functional results showed that overexpression of VPS53 could suppress proliferation, migration, and invasion, and accelerate apoptosis and autophagy of CRC cells. Also, VPS53 could upregulate Beclin 1 and LC3BII, suggesting the inductive effect of VPS53 on CRC cell autophagy. Furthermore, it was found that the autophagy inhibitor (Inhb) could attenuate the inhibition of VPS53 on CRC progression. CONCLUSION: VPS53 repressed CRC progression by regulating the autophagy signaling pathway, suggesting that VPS53 might be a promising therapeutic target for CRC.

Immunization with a bivalent adenovirus-vectored tuberculosis vaccine provides markedly improved protection over its monovalent counterpart against pulmonary tuberculosis.

Recombinant virus-vectored vaccines hold great promise for tuberculosis (TB) vaccination strategies. However, there is a lack of side-by-side comparative investigations to dissect the functional differences and support the advantage of multivalent virus-vectored vaccine over its monovalent counterpart. We previously successfully developed a monovalent adenovirus (Ad)-vectored vaccine expressing Ag85a (AdAg85a) and demonstrated its superior protective efficacy in models of pulmonary TB. In this study, we have developed a bivalent Ad TB vaccine expressing Ag85a and TB10.4 antigens as a fusion protein (AdAg85a:TB10.4) and compared its T-cell-activating and immune protective efficacy with that by monovalent AdAg85a. A single intranasal (i.n.) administration of AdAg85a:TB10.4 induced robust T-cell responses toward the respective antigens within the airway lumen and spleen, although the level of Ag85a-specific T-cell responses in the airway lumen triggered by bivalent AdAg85a:TB10.4 was lower than that by its monovalent counterpart at earlier time points. Thus, a single i.n. delivery of AdAg85a:TB10.4 conferred a markedly improved and sustained level of protection in the lung against Mycobacterium tuberculosis (M.tb) challenge over that by AdAg85a or by conventional BCG immunization with similarly induced levels of protection in the spleen. Our results indicate a unique advantage of multivalent viral-vectored TB vaccines for immunization against pulmonary TB.