Optimization and Dose Estimation of Aerosol Delivery to Non-Human Primates

Background: In pre-clinical animal studies, the uniformity of dosing across subjects and routes of administration is a crucial requirement. In preparation for a study in which aerosolized live-attenuated measles virus vaccine was administered to cynomolgus monkeys (Macaca fascicularis) by inhalation, we assessed the percentage of a nebulized dose inhaled under varying conditions. Methods: Drug delivery varies with breathing parameters. Therefore we determined macaque breathing patterns (tidal volume, breathing frequency, and inspiratory to expiratory (I:E) ratio) across a range of 3.3-6.5 kg body weight, using a pediatric pneumotachometer interfaced either with an endotracheal tube or a facemask. Subsequently, these breathing patterns were reproduced using a breathing simulator attached to a filter to collect the inhaled dose. Albuterol was nebulized using a vibrating mesh nebulizer and the percentage inhaled dose was determined by extraction of drug from the filter and subsequent quantification. Results: Tidal volumes ranged from 24 to 46 mL, breathing frequencies from 19 to 31 breaths per minute and I:E ratios from 0.7 to 1.6. A small pediatric resuscitation mask was identified as the best fitting interface between animal and pneumotachometer. The average efficiency of inhaled dose delivery was 32.1% (standard deviation 7.5, range 24%-48%), with variation in tidal volumes as the most important determinant. Conclusions: Studies in non-human primates aimed at comparing aerosol delivery with other routes of administration should take both the inter-subject variation and relatively low efficiency of delivery to these low body weight mammals into account

Optimization and Dose Estimation of Aerosol Delivery to Non-Human Primates

Background: In pre-clinical animal studies, the uniformity of dosing across subjects and routes of administration is a crucial requirement. In preparation for a study in which aerosolized live-attenuated measles virus vaccine was administered to cynomolgus monkeys (Macaca fascicularis) by inhalation, we assessed the percentage of a nebulized dose inhaled under varying conditions. Methods: Drug delivery varies with breathing parameters. Therefore we determined macaque breathing patterns (tidal volume, breathing frequency, and inspiratory to expiratory (I:E) ratio) across a range of 3.3-6.5 kg body weight, using a pediatric pneumotachometer interfaced either with an endotracheal tube or a facemask. Subsequently, these breathing patterns were reproduced using a breathing simulator attached to a filter to collect the inhaled dose. Albuterol was nebulized using a vibrating mesh nebulizer and the percentage inhaled dose was determined by extraction of drug from the filter and subsequent quantification. Results: Tidal volumes ranged from 24 to 46 mL, breathing frequencies from 19 to 31 breaths per minute and I: E ratios from 0.7 to 1.6. A small pediatric resuscitation mask was identified as the best fitting interface between animal and pneumotachometer. The average efficiency of inhaled dose delivery was 32.1% (standard deviation 7.5, range 24%-48%), with variation in tidal volumes as the most important determinant. Conclusions: Studies in non-human primates aimed at comparing aerosol delivery with other routes of administration should take both the inter-subject variation and relatively low efficiency of delivery to these low body weight mammals into account

Aerosol immunization with influenza matrix, nucleoprotein, or both prevents lung disease in pig

Current influenza vaccines are strain-specific and require frequent updates to combat new strains, making a broadly protective influenza vaccine (BPIV) highly desirable. A promising strategy is to induce T-cell responses against internal proteins conserved across influenza strains. In this study, pH1N1 pre-exposed pigs were immunized by aerosol using viral vectored vaccines (ChAdOx2 and MVA) expressing matrix (M1) and nucleoprotein (NP). Following H3N2 challenge, all immunizations (M1, NP or NPM1) reduced lung pathology, but M1 alone offered the greatest protection. NP or NPM1 immunization induced both T-cell and antibody responses. M1 immunization generated no detectable antibodies but elicited M1-specific T-cell responses, suggesting T cell-mediated protection. Additionally, a single aerosol immunization with the ChAdOx vaccine encoding M1, NP and neuraminidase reduced lung pathology. These findings provide insights into BPIV development using a relevant large natural host, the pig

Modified Vaccinia Virus Ankara Preferentially Targets Antigen Presenting Cells in Vitro, Ex Vivo and in Vivo

Modified Vaccinia virus Ankara (MVA) is a promising vaccine vector with an excellent safety profile. However, despite extensive pre-clinical and clinical testing, surprisingly little is known about the cellular tropism of MVA, especially in relevant animal species. Here, we performed in vitro, ex vivo and in vivo experiments with recombinant MVA expressing green fluorescent protein (rMVA-GFP). In both human peripheral blood mononuclear cells and mouse lung explants, rMVA-GFP predominantly infected antigen presenting cells. Subsequent in vivo experiments performed in mice, ferrets and non-human primates indicated that preferential targeting of dendritic cells and alveolar macrophages was observed after respiratory administration, although subtle differences were observed between the respective animal species. Following intramuscular injection, rMVA-GFP was detected in interdigitating cells between myocytes, but also in myocytes themselves. These data are important in advancing our understanding of the basis for the immunogenicity of MVA-based vaccines and aid rational vaccine design and delivery strategies

Evaluation of Aerosol Drug Delivery Options during Adult Mechanical Ventilation in the COVID-19 Era

Drug delivery devices used for aerosol therapy during mechanical ventilation to ease the symptoms of respiratory diseases provide beneficial treatment but can also pose challenges. Reflecting the significant changes in global guidance around aerosol usage and lung-protective ventilation strategies, seen in response to the COVID-19 pandemic, for the first time, we describe the drug delivery performance of commonly used devices under these conditions. Here, vibrating mesh nebuliser (VMN), jet nebuliser (JN) and pressurised metered-dose inhaler (pMDI) performance was assessed during simulated adult mechanical ventilation. Both standard test breathing patterns and those representatives of low tidal volume (LTV) ventilation with concurrent active and passive humidification were investigated. Drug delivery using a VMN was significantly greater than that with a JN and pMDI for both standard and LTV ventilation. Humidification type did not affect the delivered dose across all device types for standard ventilation. Significant variability in the pMDI dosing was evident, depending on the timing of actuation and the adapter type used. pMDI actuation synchronised with inspiration resulted in a higher delivered drug dose. The type of adapter used for pMDI actuation influenced drug delivery, with the highest dose observed using the CombiHaler

Aerosol-mediated delivery of aav2/6-iκbα attenuates lipopolysaccharide-induced acute lung injury in rats

Inhibition of the proinflammatory transcription factor NF-kappa B has previously been shown to attenuate the inflammatory response in tissue after injury. However, the feasibility and efficacy of aerosolized adeno-associated viral (AAV) vector-delivered transgenes to inhibit the NF-kappa B pathway are less clear. Initial studies optimized the AAV vector for delivery of transgenes to the pulmonary epithelium. The effect of repeated nebulization on the integrity and transduction efficacy of the AAV vector was then examined. Subsequent in vivo studies examined the efficacy of aerosolized rAAV2/6 overexpressing the NF-kappa B inhibitor I kappa B alpha in a rodent endotoxin-induced lung injury model. Initial in vitro investigations indicated that rAAV2/6 was the most effective vector to transduce the lung epithelium, and maintained its integrity and transduction efficacy after repeated nebulization. In our in vivo studies, animals that received aerosolized rAAV2/6-I kappa B alpha demonstrated a significant increase in total I kappa B alpha levels in lung tissue relative to null vector-treated animals. Aerosolized rAAV2/6-I kappa B alpha attenuated endotoxin-induced bronchoalveolar lavage-detected neutrophilia, interleukin-6 and cytokine-induced neutrophil chemoattractant-1 levels, as well as total protein content, and decreased histologic indices of injury. These results demonstrate that aerosolized AAV vectors encoding human I kappa B alpha significantly attenuate endotoxin-mediated lung injury and may be a potential therapeutic candidate in the treatment of acute lung injury

Aerosol-mediated delivery of aav2/6-iκbα attenuates lipopolysaccharide-induced acute lung injury in rats

Inhibition of the proinflammatory transcription factor NF-kappa B has previously been shown to attenuate the inflammatory response in tissue after injury. However, the feasibility and efficacy of aerosolized adeno-associated viral (AAV) vector-delivered transgenes to inhibit the NF-kappa B pathway are less clear. Initial studies optimized the AAV vector for delivery of transgenes to the pulmonary epithelium. The effect of repeated nebulization on the integrity and transduction efficacy of the AAV vector was then examined. Subsequent in vivo studies examined the efficacy of aerosolized rAAV2/6 overexpressing the NF-kappa B inhibitor I kappa B alpha in a rodent endotoxin-induced lung injury model. Initial in vitro investigations indicated that rAAV2/6 was the most effective vector to transduce the lung epithelium, and maintained its integrity and transduction efficacy after repeated nebulization. In our in vivo studies, animals that received aerosolized rAAV2/6-I kappa B alpha demonstrated a significant increase in total I kappa B alpha levels in lung tissue relative to null vector-treated animals. Aerosolized rAAV2/6-I kappa B alpha attenuated endotoxin-induced bronchoalveolar lavage-detected neutrophilia, interleukin-6 and cytokine-induced neutrophil chemoattractant-1 levels, as well as total protein content, and decreased histologic indices of injury. These results demonstrate that aerosolized AAV vectors encoding human I kappa B alpha significantly attenuate endotoxin-mediated lung injury and may be a potential therapeutic candidate in the treatment of acute lung injury

Optimization and dose estimation of aerosol delivery to non-human primates

Background: In pre-clinical animal studies, the uniformity of dosing across subjects and routes of administration is a crucial requirement. In preparation for a study in which aerosolized live-attenuated measles virus vaccine was administered to cynomolgus monkeys (Macaca fascicularis) by inhalation, we assessed the percentage of a nebulized dose inhaled under varying conditions. Methods: Drug delivery varies with breathing parameters. Therefore we determined macaque breathing patterns (tidal volume, breathing frequency, and inspiratory to expiratory (I:E) ratio) across a range of 3.3-6.5 kg body weight, using a pediatric pneumotachometer interfaced either with an endotracheal tube or a facemask. Subsequently, these breathing patterns were reproduced using a breathing simulator attached to a filter to collect the inhaled dose. Albuterol was nebulized using a vibrating mesh nebulizer and the percentage inhaled dose was determined by extraction of drug from the filter and subsequent quantification. Results: Tidal volumes ranged from 24 to 46 mL, breathing frequencies from 19 to 31 breaths per minute and I: E ratios from 0.7 to 1.6. A small pediatric resuscitation mask was identified as the best fitting interface between animal and pneumotachometer. The average efficiency of inhaled dose delivery was 32.1% (standard deviation 7.5, range 24%-48%), with variation in tidal volumes as the most important determinant. Conclusions: Studies in non-human primates aimed at comparing aerosol delivery with other routes of administration should take both the inter-subject variation and relatively low efficiency of delivery to these low body weight mammals into account

Optimization and dose estimation of aerosol delivery to non-human primates

Background: In pre-clinical animal studies, the uniformity of dosing across subjects and routes of administration is a crucial requirement. In preparation for a study in which aerosolized live-attenuated measles virus vaccine was administered to cynomolgus monkeys (Macaca fascicularis) by inhalation, we assessed the percentage of a nebulized dose inhaled under varying conditions. Methods: Drug delivery varies with breathing parameters. Therefore we determined macaque breathing patterns (tidal volume, breathing frequency, and inspiratory to expiratory (I:E) ratio) across a range of 3.3-6.5 kg body weight, using a pediatric pneumotachometer interfaced either with an endotracheal tube or a facemask. Subsequently, these breathing patterns were reproduced using a breathing simulator attached to a filter to collect the inhaled dose. Albuterol was nebulized using a vibrating mesh nebulizer and the percentage inhaled dose was determined by extraction of drug from the filter and subsequent quantification. Results: Tidal volumes ranged from 24 to 46 mL, breathing frequencies from 19 to 31 breaths per minute and I: E ratios from 0.7 to 1.6. A small pediatric resuscitation mask was identified as the best fitting interface between animal and pneumotachometer. The average efficiency of inhaled dose delivery was 32.1% (standard deviation 7.5, range 24%-48%), with variation in tidal volumes as the most important determinant. Conclusions: Studies in non-human primates aimed at comparing aerosol delivery with other routes of administration should take both the inter-subject variation and relatively low efficiency of delivery to these low body weight mammals into account