In vitro and in vivo characterization of poractant alfa supplemented with budesonide for safe and effective intratracheal administration

Thermodynamic and Structural Study of Budesonide-Exogenous Lung Surfactant System

The clinical benefits of using exogenous pulmonary surfactant (EPS) as a carrier of budesonide (BUD), a non-halogenated corticosteroid with a broad anti-inflammatory effect, have been established. Using various experimental techniques (differential scanning calorimetry DSC, small- and wide- angle X-ray scattering SAXS/WAXS, small- angle neutron scattering SANS, fluorescence spectroscopy, dynamic light scattering DLS, and zeta potential), we investigated the effect of BUD on the thermodynamics and structure of the clinically used EPS, Curosurf®. We show that BUD facilitates the Curosurf® phase transition from the gel to the fluid state, resulting in a decrease in the temperature of the main phase transition (Tm) and enthalpy (ΔH). The morphology of the Curosurf® dispersion is maintained for BUD < 10 wt% of the Curosurf® mass; BUD slightly increases the repeat distance d of the fluid lamellar phase in multilamellar vesicles (MLVs) resulting from the thickening of the lipid bilayer. The bilayer thickening (~0.23 nm) was derived from SANS data. The presence of ~2 mmol/L of Ca2+ maintains the effect and structure of the MLVs. The changes in the lateral pressure of the Curosurf® bilayer revealed that the intercalated BUD between the acyl chains of the surfactant's lipid molecules resides deeper in the hydrophobic region when its content exceeds ~6 wt%. Our studies support the concept of a combined therapy utilising budesonide-enriched Curosurf®.

Surfactant replacement therapy as promising treatment for COVID-19: an updated narrative review

Patients with COVID-19 exhibit similar symptoms to neonatal respiratory distress syndrome. SARS-CoV-2 spike protein has been shown to target alveolar type 2 lung cells which synthesize and secrete endogenous surfactants leading to acute respiratory distress syndrome in some patients. This was proven by post-mortem histopathological findings revealing desquamated alveolar type 2 cells. Surfactant use in patients with COVID-19 respiratory distress syndrome results in marked improvement in respiratory parameters but not mortality which needs further clinical trials comparing surfactant formulas and modes of administration to decrease the mortality. In addition, surfactants could be a promising vehicle for specific drug delivery as a liposomal carrier, which requires more and more challenging efforts. In this review, we highlight the current reviews and two clinical trials on exogenous surfactant therapy in COVID-19-associated respiratory distress in adults, and how surfactant could be a promising drug to help fight the COVID-19 infection.

Intratracheal budesonide mixed with surfactant to increase survival free of bronchopulmonary dysplasia in extremely preterm infants: study protocol for the international, multicenter, randomized PLUSS trial

BACKGROUND

Bronchopulmonary dysplasia (BPD), an inflammatory-mediated chronic lung disease, is common in extremely preterm infants born before 28 weeks' gestation and is associated with an increased risk of adverse neurodevelopmental and respiratory outcomes in childhood. Effective and safe prophylactic therapies for BPD are urgently required. Systemic corticosteroids reduce rates of BPD in the short-term but are associated with poorer neurodevelopmental outcomes if given to ventilated infants in the first week after birth. Intratracheal administration of corticosteroid admixed with exogenous surfactant could overcome these concerns by minimizing systemic sequelae. Several small, randomized trials have found intratracheal budesonide in a surfactant vehicle to be a promising therapy to increase survival free of BPD.

METHODS

An international, multicenter, double-blinded, randomized trial of intratracheal budesonide (a corticosteroid) mixed with surfactant for extremely preterm infants to increase survival free of BPD at 36 weeks' postmenstrual age (PMA; primary outcome). Extremely preterm infants aged < 48 h after birth are eligible if: (1) they are mechanically ventilated, or (2) they are receiving non-invasive respiratory support and there is a clinical decision to treat with surfactant. The intervention is budesonide (0.25 mg/kg) mixed with poractant alfa (200 mg/kg first intervention, 100 mg/kg if second intervention), administered intratracheally via an endotracheal tube or thin catheter. The comparator is poractant alfa alone (at the same doses). Secondary outcomes include the components of the primary outcome (death, BPD prior to or at 36 weeks' PMA), potential systemic side effects of corticosteroids, cost-effectiveness, early childhood health until 2 years of age, and neurodevelopmental outcomes at 2 years of age (corrected for prematurity).

DISCUSSION

Combining budesonide with surfactant for intratracheal administration is a simple intervention that may reduce BPD in extremely preterm infants and translate into health benefits in later childhood. The PLUSS trial is powered for the primary outcome and will address gaps in the evidence due to its pragmatic and inclusive design, targeting all extremely preterm infants regardless of their initial mode of respiratory support. Should intratracheal budesonide mixed with surfactant increase survival free of BPD, without severe adverse effects, this readily available intervention could be introduced immediately into clinical practice.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( https://www.anzctr.org.au ), ACTRN12617000322336. First registered on 28th February 2017.

Time-resolved transcriptomic profiling of the developing rabbit's lungs: impact of premature birth and implications for modelling bronchopulmonary dysplasia

BACKGROUND

Premature birth, perinatal inflammation, and life-saving therapies such as postnatal oxygen and mechanical ventilation are strongly associated with the development of bronchopulmonary dysplasia (BPD); these risk factors, alone or combined, cause lung inflammation and alter programmed molecular patterns of normal lung development. The current knowledge on the molecular regulation of lung development mainly derives from mechanistic studies conducted in newborn rodents exposed to postnatal hyperoxia, which have been proven useful but have some limitations.

METHODS

Here, we used the rabbit model of BPD as a cost-effective alternative model that mirrors human lung development and, in addition, enables investigating the impact of premature birth per se on the pathophysiology of BPD without further perinatal insults (e.g., hyperoxia, LPS-induced inflammation). First, we characterized the rabbit's normal lung development along the distinct stages (i.e., pseudoglandular, canalicular, saccular, and alveolar phases) using histological, transcriptomic and proteomic analyses. Then, the impact of premature birth was investigated, comparing the sequential transcriptomic profiles of preterm rabbits obtained at different time intervals during their first week of postnatal life with those from age-matched term pups.

RESULTS

Histological findings showed stage-specific morphological features of the developing rabbit's lung and validated the selected time intervals for the transcriptomic profiling. Cell cycle and embryo development, oxidative phosphorylation, and WNT signaling, among others, showed high gene expression in the pseudoglandular phase. Autophagy, epithelial morphogenesis, response to transforming growth factor β, angiogenesis, epithelium/endothelial cells development, and epithelium/endothelial cells migration pathways appeared upregulated from the 28th day of gestation (early saccular phase), which represents the starting point of the premature rabbit model. Premature birth caused a significant dysregulation of the inflammatory response. TNF-responsive, NF-κB regulated genes were significantly upregulated at premature delivery and triggered downstream inflammatory pathways such as leukocyte activation and cytokine signaling, which persisted upregulated during the first week of life. Preterm birth also dysregulated relevant pathways for normal lung development, such as blood vessel morphogenesis and epithelial-mesenchymal transition.

CONCLUSION

These findings establish the 28-day gestation premature rabbit as a suitable model for mechanistic and pharmacological studies in the context of BPD.

Corticosteroids in the prevention and treatment of infants with bronchopulmonary dysplasia: Part II. Inhaled corticosteroids alone or in combination with surfactants

This paper is the second in a two-part State-of-the-Art series that reviews the latest relevant clinical trials investigating the short-term and long-term effects of corticosteroids in the prevention and treatment of bronchopulmonary dysplasia (BPD). Inhaled postnatal corticosteroids demonstrate low systemic bioavailability and rapid systemic clearance with high pulmonary deposition and were expected to reduce the incidence of BPD with reduced adverse effects, however, increased rate of mortality in the neonatal period and at the 18-24 months follow-up was observed. In a milestone study, intratracheal instillation of corticosteroids combined with surfactant decreased the incidence of BPD without increasing the mortality or the long-term neurodevelopmental adverse outcomes. However, subsequent trials using different types of surfactants, different surfactant to budesonide ratio, different time of the drug administration for infants with different severity of respiratory distress syndrome could not reproduce all the beneficial effects. Future perspectives for the identification of premature infants at high risk of BPD and the prevention or treatment of established BPD are discussed.

A transcriptomics-guided drug target discovery strategy identifies receptor ligands for lung regeneration

Currently, there is no pharmacological treatment targeting defective tissue repair in chronic disease. Here, we used a transcriptomics-guided drug target discovery strategy using gene signatures of smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke, identifying druggable targets expressed in alveolar epithelial progenitors, of which we screened the function in lung organoids. We found several drug targets with regenerative potential, of which EP and IP prostanoid receptor ligands had the most profound therapeutic potential in restoring cigarette smoke-induced defects in alveolar epithelial progenitors in vitro and in vivo. Mechanistically, we found, using single-cell RNA sequencing analysis, that circadian clock and cell cycle/apoptosis signaling pathways were differentially expressed in alveolar epithelial progenitor cells in patients with COPD and in a relevant model of COPD, which was prevented by prostaglandin E2 or prostacyclin mimetics. We conclude that specific targeting of EP and IP receptors offers therapeutic potential for injury to repair in COPD.

Pulmonary surfactant: a unique biomaterial with life-saving therapeutic applications

Pulmonary surfactant is a complex lipoprotein mixture secreted into the alveolar lumen by type 2 pneumocytes, which is composed by tens of different lipids (approximately 90% of its entire mass) and surfactant proteins (approximately 10% of the mass). It is crucially involved in maintaining lung homeostasis by reducing the values of alveolar liquid surface tension close to zero at end-expiration, thereby avoiding the alveolar collapse, and assembling a chemical and physical barrier against inhaled pathogens. A deficient amount of surfactant or its functional inactivation is directly linked to a wide range of lung pathologies, including the neonatal respiratory distress syndrome. This paper reviews the main biophysical concepts of surfactant activity and its inactivation mechanisms, and describes the past, present and future roles of surfactant replacement therapy, focusing on the exogenous surfactant preparations marketed worldwide and new formulations under development. The closing section describes the pulmonary surfactant in the context of drug delivery. Thanks to its peculiar composition, biocompatibility, and alveolar spreading capability, the surfactant may work not only as a shuttle to the branched anatomy of the lung for other drugs but also as a modulator for their release, opening to innovative therapeutic avenues for the treatment of several respiratory diseases.

Efficacy of intratracheal budesonide-surfactant combined therapy in surfactant-insufficient rat lungs with lipopolysaccharide insult

BACKGROUND

Intratracheal steroid therapy for lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains challenging particularly in surfactant-insufficient lungs, a common problem of neonatal or pediatric ALI. Surfactant has been used as a vehicle for intratracheal steroid in the treatment of other types of ALI. This study investigated the efficacy of intratracheal budesonide (BUD) delivered by two concentrations of surfactant in the treatment of LPS-induced ALI in surfactant-insufficient rat lungs.

METHODS

Male adult rats were anesthetized and ventilated. Our ALI model was established by repeated saline lavage to produce surfactant insufficiency, followed by intratracheal LPS instillation. Five study groups (n = 5 for each) with different intratracheal treatments following ALI were used: control (no treatment), BUD (NS-BUD; BUD in saline), DS-BUD (BUD in diluted surfactant), FS-BUD (BUD in full-strength surfactant), FS (full-strength surfactant). Cardiopulmonary variables were monitored 4 hours post injury. Histological and immunohistochemical assessments of the lungs were performed.

RESULTS

The FS-BUD and FS groups presented better gas exchange, less metabolic acidosis, less oxygen index, and more stable hemodynamic changes than the DS-BUD, NS-BUD, and control groups. The total lung injury scores assessed by histological examination were ordered as follows: FS-BUD < DS-BUD or FS < NS-BUD < control. The immunostaining intensities of lung myeloperoxidase showed the following order: NS-BUD, DS-BUD, or FS-BUD < control or FS. Only the FS-BUD group displayed a smaller immunostaining intensity of lung tumor necrosis factor (TNF)-α than the control group.

CONCLUSION

Among our therapeutic strategies, intratracheal BUD delivered by full-strength surfactant confers an optimal protection against LPS-induced ALI in surfactant-insufficient rat lungs.

Intra-tracheal surfactant/budesonide versus surfactant alone: Comparison of two consecutive cohorts of extremely preterm infants

OBJECTIVES

To compare the efficacy of intra-tracheal (IT) surfactant/budesonide (SB) with that of surfactant alone (S) in reducing the rate of bronchopulmonary dysplasia (BPD) at 36 weeks post-menstrual age (PMA), we included extremely preterm very low birth weight (VLBW) infants with severe respiratory distress syndrome (RDS) in our tertiary neonatal level of care unit (Padua, Italy).

STUDY DESIGN

A retrospective chart review of two cohorts of extremely preterm VLBW neonates (<28⁺⁰  gestation weeks, birth weight [BW] < 1500 g) born in two consequent epochs (2017-2018/2018-2019) were compared. The SB group received surfactant (200 mg/kg 1st dose) and budesonide (0.25 mg/kg), while the S group received surfactant alone.

RESULTS

Among 68 neonates with RDS Grades III-IV, FiO₂  ≥ 0.3 within 12 h of life, 18 were included in each group after matching for perinatal, clinical, and laboratory characteristics. IT SB did not affect the rate of BPD (Vermont Oxford Network, Jensen's, and National Institute of Child Health and Human Development BPD Workshop 2018 definitions), death, BPD, or death at 36 weeks PMA. Hypotension requiring inotropic support within the first 5 days was lower in those receiving the combined treatment (p = .03). The SB group had fewer admissions to pediatric ward due to respiratory causes up to 12 months of corrected age (p = .03).

CONCLUSION

The preliminary results of this retrospective study suggest that in extremely preterm VLBW infants, IT SB for severe RDS did not affect the incidence of BPD, death, and BPD or death at 36 weeks PMA, compared to surfactant alone. The combined therapy proved to be safe in this population. Further studies are warranted to explore the role of early IT steroids on respiratory morbidity in preterm infants.

Surfactant-Assisted Distal Pulmonary Distribution of Budesonide Revealed by Mass Spectrometry Imaging

Direct lung administration of budesonide in combination with surfactant reduces the incidence of bronchopulmonary dysplasia. Although the therapy is currently undergoing clinical development, the lung distribution of budesonide throughout the premature neonatal lung has not yet been investigated. Here, we applied mass spectrometry imaging (MSI) to investigate the surfactant-assisted distal lung distribution of budesonide. Unlabeled budesonide was either delivered using saline as a vehicle (n = 5) or in combination with a standard dose of the porcine surfactant Poractant alfa (n = 5). These lambs were ventilated for one minute, and then the lungs were extracted for MSI analysis. Another group of lambs (n = 5) received the combination of budesonide and Poractant alfa, followed by two hours of mechanical ventilation. MSI enabled the label-free detection and visualization of both budesonide and the essential constituent of Poractant alfa, the porcine surfactant protein C (SP-C). 2D ion intensity images revealed a non-uniform distribution of budesonide with saline, which appeared clustered in clumps. In contrast, the combination therapy showed a more homogeneous distribution of budesonide throughout the sample, with more budesonide distributed towards the lung periphery. We found similar distribution patterns for the SP-C and budesonide in consecutive lung tissue sections, indicating that budesonide was transported across the lungs associated with the exogenous surfactant. After two hours of mechanical ventilation, the budesonide intensity signal in the 2D ion intensity maps dropped dramatically, suggesting a rapid lung clearance and highlighting the relevance of achieving a uniform surfactant-assisted lung distribution of budesonide early after delivery to maximize the anti-inflammatory and maturational effects throughout the lung.

Sample preparation strategy for the detection of steroid-like compounds using MALDI mass spectrometry imaging: pulmonary distribution of budesonide as a case study

Corticosteroids as budesonide can be effective in reducing topic inflammation processes in different organs. Therapeutic use of budesonide in respiratory diseases, like asthma, chronic obstructive pulmonary disease, and allergic rhinitis is well known. However, the pulmonary distribution of budesonide is not well understood, mainly due to the difficulties in tracing the molecule in lung samples without the addition of a label. In this paper, we present a matrix-assisted laser desorption/ionization mass spectrometry imaging protocol that can be used to visualize the pulmonary distribution of budesonide administered to a surfactant-depleted adult rabbit. Considering that budesonide is not easily ionized by MALDI, we developed an on-tissue derivatization method with Girard’s reagent P followed by ferulic acid deposition as MALDI matrix. Interestingly, this sample preparation protocol results as a very effective strategy to raise the sensitivity towards not only budesonide but also other corticosteroids, allowing us to track its distribution and quantify the drug inside lung samples.

Aerosol drug delivery to spontaneously-breathing preterm neonates: lessons learned

Delivery of medications to preterm neonates receiving non-invasive ventilation (NIV) represents one of the most challenging scenarios for aerosol medicine. This challenge is highlighted by the undersized anatomy and the complex (patho)physiological characteristics of the lungs in such infants. Key physiological restraints include low lung volumes, low compliance, and irregular respiratory rates, which significantly reduce lung deposition. Such factors are inherent to premature birth and thus can be regarded to as the intrinsic factors that affect lung deposition. However, there are a number of extrinsic factors that also impact lung deposition: such factors include the choice of aerosol generator and its configuration within the ventilation circuit, the drug formulation, the aerosol particle size distribution, the choice of NIV type, and the patient interface between the delivery system and the patient. Together, these extrinsic factors provide an opportunity to optimize the lung deposition of therapeutic aerosols and, ultimately, the efficacy of the therapy.

In this review, we first provide a comprehensive characterization of both the intrinsic and extrinsic factors affecting lung deposition in premature infants, followed by a revision of the clinical attempts to deliver therapeutic aerosols to premature neonates during NIV, which are almost exclusively related to the non-invasive delivery of surfactant aerosols. In this review, we provide clues to the interpretation of existing experimental and clinical data on neonatal aerosol delivery and we also describe a frame of measurable variables and available tools, including in vitro and in vivo models, that should be considered when developing a drug for inhalation in this important but under-served patient population.

Budesonide mixed with surfactant did not affect neurodevelopmental outcomes at 6 or 18 months corrected age in observational cohorts

BACKGROUND

The addition of budesonide to surfactant in very-low-birth-weight infants with less severe RDS decreased bronchopulmonary dysplasia (BPD) severity. Long-term neurodevelopmental follow-up was needed to monitor for systemic effects of budesonide.

METHODS

Infants ≤1250 g who received intratracheal budesonide (0.25 mg/kg) with surfactant (n = 173) were compared to a historical cohort who received surfactant alone (n = 294). Peabody Developmental Motor Scales II at 4-6 months corrected age and Bayley Scales of Infant & Toddler Development III at 18-22 months corrected age were compared.

RESULTS

There were no differences in muscle tone or motor skills by Peabody exam. There were no differences in the cognitive, language, or motor domains between cohorts on Bayley III.

CONCLUSIONS

In a cohort of infants treated with budesonide mixed with surfactant, there were no differences in developmental outcomes at 4-6 months or 18-22 months corrected age.

Surfactant lung delivery with LISA and InSurE in adult rabbits with respiratory distress

BACKGROUND

In preterm infants, InSurE (Intubation-Surfactant-Extubation) and LISA (less invasive surfactant administration) techniques allow for exogenous surfactant administration while reducing lung injury associated with mechanical ventilation. We compared the acute pulmonary response and lung deposition of surfactant by LISA and InSurE in surfactant-depleted adult rabbits.

METHODS

Twenty-six spontaneously breathing surfactant-depleted adult rabbits (6-7 weeks old) with moderate RDS and managed with nasal continuous positive airway pressure were randomized to 3 groups: (1) 200 mg/kg of surfactant by InSurE; (2) 200 mg/kg of surfactant by LISA; (3) no surfactant treatment (Control). Gas exchange and lung mechanics were monitored for 180 min. After that, surfactant lung deposition and distribution were evaluated monitoring disaturated-phosphatidylcholine (DSPC) and surfactant protein C (SP-C), respectively.

RESULTS

No signs of recovery were found in the untreated animals. After InSurE, oxygenation improved more rapidly compared to LISA. However, at 180' LISA and InSurE showed comparable outcomes in terms of gas exchange, ventilation parameters, and lung mechanics. Neither DSPC in the alveolar pool nor SP-C signal distributions in a frontal lung section were significantly different between InSurE and LISA groups.

CONCLUSIONS

In an acute setting, LISA demonstrated efficacy and surfactant lung delivery similar to that of InSurE in surfactant-depleted adult rabbits.

IMPACT

Although LISA technique is gaining popularity, there are still several questions to address. This is the first study comparing LISA and InSurE in terms of gas exchange, ventilation parameters, and lung mechanics as well as surfactant deposition and distribution. In our animal study, three hours post-treatment, LISA method seems to be as effective as InSurE and showed similar surfactant lung delivery. Our findings provide some clarifications on a fair comparison between LISA and InSurE techniques, particularly in terms of surfactant delivery. They should reassure some of the concerns raised by the clinical community on LISA adoption in neonatal units.

Intratracheal budesonide/surfactant attenuates hyperoxia-induced lung injury in preterm rabbits

Recent clinical trials have shown improvements in neonatal outcomes after intratracheal administration of a combination of budesonide/surfactant (ITBS) in infants at risk of bronchopulmonary dysplasia. However, the effect of ITBS on lung function and alveolar structure is not known. We aimed to determine the effect of ITBS on lung function, parenchymal structure, and inflammatory cytokine expression in a relevant preterm animal model for bronchopulmonary dysplasia. Premature neonatal rabbits were administered a single dose of ITBS on the day of delivery and exposed to 95% oxygen. Following 7 days of hyperoxia, in vivo forced oscillation and pressure-volume maneuvers were performed to examine pulmonary function. Histological and molecular analysis was performed to assess alveolar and extracellular matrix (ECM) morphology, along with gene expression of connective tissue growth factor (CTGF), IL-8, and CCL-2. ITBS attenuated the functional effect of hyperoxia-induced lung injury and limited the change to respiratory system impedance, measured using the forced oscillation technique. Treatment effects were most obvious in the small airways, with significant effects on small airway resistance and small airway reactance. In addition, ITBS mitigated the decrease in inspiratory capacity and static compliance. ITBS restricted alveolar septal thickening without altering the mean linear intercept and mitigated hyperoxia-induced remodeling of the ECM. These structural changes were associated with improved inspiratory capacity and lung compliance. Gene expression of CTGF, IL-8, and CCL-2 was significantly downregulated in the lung. Treatment with ITBS shortly after delivery attenuated the functional and structural consequences of hyperoxia-induced lung injury to day 7 of life in the preterm rabbit.

Surfactant and budesonide for respiratory distress syndrome: an observational study

BACKGROUND

In preterm infants on moderately high ventilator support, the addition of budesonide to surfactant lowered bronchopulmonary dysplasia (BPD) rates by 20% without increased morbidity or mortality. The aim of this cohort comparison was to determine the safety and efficacy of the combination in infants with milder respiratory distress syndrome (RDS).

METHODS

In August 2016 we began administering budesonide (0.25 mg/kg) mixed with surfactant (Survanta 4 mL/kg) to all infants ≤ 1250 g who failed CPAP and required intubation. Infants were compared to a historical cohort (2013-2016) who received surfactant alone.

RESULTS

BPD or death did not change between the historical surfactant cohort (71%, n = 294) and the budesonide cohort (69%, n = 173). Budesonide was associated with a decrease in the need for continued mechanical ventilation, severe BPD type II or death (19-12%), grade III BPD or death (31-21%), and the median gestational age at discharge was 1 week earlier. Histologic chorioamnionitis was associated with decreased budesonide effects. Secondary morbidities (NEC, IVH, ROP, Sepsis) were similar.

CONCLUSION

Overall BPD rates remained unchanged with the addition of budesonide. Budesonide was associated with decreased severity of BPD, decreased mechanical ventilation use, earlier discharge, and similar short-term outcomes.

In vitro characterization and in vivo comparison of the pulmonary outcomes of Poractant alfa and Calsurf in ventilated preterm rabbits

Poractant alfa and Calsurf are two natural surfactants widely used in China for the treatment of neonatal respiratory distress syndrome, which are extracted from porcine and calf lungs, respectively. The purpose of this experimental study was to compare their in vitro characteristics and in vivo effects in the improvement of pulmonary function and protection of lung injury. The biophysical properties, ultrastructure, and lipid composition of both surfactant preparations were respectively analysed in vitro by means of Langmuir-Blodgett trough (LBT), atomic force microscopy (AFM), and liquid-chromatography mass-spectrometry (LC-MS). Then, as core pharmacological activity, both head-to-head (100 and 200 mg/kg for both surfactants) and licensed dose comparisons (70 mg/kg Calsurf vs. 200 mg/kg Poractant alfa) between the two surfactants were conducted as prophylaxis in preterm rabbits with primary surfactant deficiency, assessing survival time and rate and dynamic compliance of the respiratory system (Cdyn). Intrapulmonary surfactant pools, morphometric volume density as alveolar expansion (Vv), and lung injury scores were determined post mortem. AFM and LC-MS analysis revealed qualitative differences in the ultrastructure as well as in the lipid composition of both preparations. Calsurf showed a longer plateau region of the LBT isotherm and lower film compressibility. In vivo, both surfactant preparations improved Cdyn at any dose, although maximum benefits in terms of Vv and intrapulmonary surfactant pools were seen with the 200 mg/kg dose in both surfactants. The group of animals treated with 200 mg/kg of Poractant alfa showed a prolonged survival time and rate compared to untreated but ventilated controls, and significantly ameliorated lung injury compared to Calsurf at any dose, including 200 mg/kg. The overall outcomes suggest the pulmonary effects to be dose dependent for both preparations. The group of animals treated with 200 mg/kg of Poractant alfa showed a significant reduction of mortality. Compared to Calsurf, Poractant alfa exerted better effects if licensed doses were compared, which requires further investigation.

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.

Making Medicines Baby Size: The Challenges in Bridging the Formulation Gap in Neonatal Medicine

The development of age-appropriate formulations should focus on dosage forms that can deliver variable yet accurate doses that are safe and acceptable to the child, are matched to his/her development and ability, and avoid medication errors. However, in the past decade, the medication needs of neonates have largely been neglected. The aim of this review is to expand on what differentiates the needs of preterm and term neonates from those of the older paediatric subsets, in terms of environment of care, ability to measure and administer the dose (from the perspective of the patient and carer, the routes of administration, the device and the product), neonatal biopharmaceutics and regulatory challenges. This review offers insight into those challenges posed by the formulation of medicinal products for neonatal patients in order to support the development of clinically relevant products.

Surfactant plus budesonide decreases lung and systemic inflammation in mechanically ventilated preterm sheep

Mechanical ventilation with normal tidal volumes (VT) causes lung and systemic inflammation in preterm sheep. Mechanical ventilation is associated with bronchopulmonary dysplasia (BPD) in preterm infants, and the addition of budesonide to surfactant decreases BPD in clinical trials. Budesonide with surfactant will decrease the lung injury from mechanical ventilation for 24 h in preterm sheep. Lambs at 126 ± 1 day gestational age were delivered and randomized to either: 1) surfactant (200 mg/kg) or 2) surfactant mixed with budesonide (0.25 mg/kg) before mechanical ventilation with VT of 7-8 ml/kg for 2, 6, or 24 h (n = 6 or 7/group). Lung physiology and budesonide levels in the plasma and the lung were measured. Lung tissue, bronchoalveolar lavage fluid (BALF), liver, and brain tissues were evaluated for indicators of injury. High initial budesonide plasma levels of 170 ng/ml decreased to 3 ng/ml at 24 h. Lung tissue budesonide levels were less than 1% of initial dose by 24 h. Although physiological variables were generally similar, budesonide-exposed lambs required lower mean airway pressures, had higher hyperoxia responses, and had more stable blood pressures. Budesonide decreased proinflammatory mRNA in the lung, liver, and brain. Budesonide also decreased total protein and proinflammatory cytokines in BALF, and decreased inducible nitric oxide synthase activation at 24 h. In ventilated preterm lambs, most of the budesonide left the lung within 24 h. The addition of budesonide to surfactant improved physiology, decreased markers of lung injury, and decreased systemic responses in liver and brain.

Local pulmonary drug delivery in the preterm rabbit: feasibility and efficacy of daily intratracheal injections

Recent clinical trials in newborns have successfully used surfactant as a drug carrier for an active compound, to minimize systemic exposure. To investigate the translational potential of surfactant-compound mixtures and other local therapeutics, a relevant animal model is required in which intratracheal administration for maximal local deposition is technically possible and well tolerated. Preterm rabbit pups (born at 28 days of gestation) were exposed to either hyperoxia or normoxia and randomized to receive daily intratracheal surfactant, daily intratracheal saline, or no injections for 7 days. At day 7, the overall lung function and morphology were assessed. Efficacy in terms of distribution was assessed by micro-PET-CT on both day 0 and day 7. Lung function as well as parenchymal and vascular structure were altered by hyperoxia, thereby reproducing a phenotype reminiscent of bronchopulmonary dysplasia (BPD). Neither intratracheal surfactant nor saline affected the survival or the hyperoxia-induced BPD phenotype of the pups. Using PET-CT, we demonstrate that 82.5% of the injected radioactive tracer goes and remains in the lungs, with a decrease of only 4% after 150 min. Surfactant and saline can safely and effectively be administered in spontaneously breathing preterm rabbits. The described model and method enable researchers to evaluate intratracheal pharmacological interventions for the treatment of BPD.

Effects of budesonide and surfactant in preterm fetal sheep

Mechanical ventilation causes lung injury and systemic inflammatory responses in preterm sheep and is associated with bronchopulmonary dysplasia (BPD) in preterm infants. Budesonide added to surfactant decreased BPD by 20% in infants. We wanted to determine the effects of budesonide and surfactant on injury from high tidal volume (V_T) ventilation in preterm lambs. Ewes at 125 ± 1 days gestational age had fetal surgery to expose fetal head and chest with placental circulation intact. Lambs were randomized to 1) mechanical ventilation with escalating V_T to target 15 ml/kg by 15 min or 2) continuous positive airway pressure (CPAP) of 5 cmH₂O. After the 15-min intervention, lambs were given surfactant 100 mg/kg with saline, budesonide 0.25 mg/kg, or budesonide 1 mg/kg. The fetuses were returned to the uterus for 24 h and then delivered and ventilated for 30 min to assess lung function. Budesonide levels were low in lung and plasma. CPAP groups had improved oxygenation, ventilation, and decreased injury markers compared with fetal V_T lambs. Budesonide improved ventilation in CPAP lambs. Budesonide decreased lung weights and lung liquid and increased lung compliance and surfactant protein mRNA. Budesonide decreased proinflammatory and acute-phase responses in lung. Airway thickness increased in animals not receiving budesonide. Systemically, budesonide decreased monocyte chemoattractant protein-1 mRNA and preserved glycogen in liver. Results with 0.25 and 1 mg/kg budesonide were similar. We concluded that budesonide with surfactant matured the preterm lung and decreased the liver responses but did not improve lung function after high V_T injury in fetal sheep.