Impact of neonatal noninvasive resuscitation strategies on lung mechanics, tracheal pressure, and tidal volume in preterm lambs.

This study investigated the relationship between three respiratory support approaches on lung volume recruitment during the first 2 h of postnatal life in preterm lambs. We estimated changes in lung aeration, measuring respiratory resistance and reactance by oscillometry at 5 Hz. We also measured intratracheal pressure in subsets of lambs.

Mesenchymal stromal cell extracellular vesicles improve lung development in mechanically ventilated preterm lambs.

Novel therapies are needed for bronchopulmonary dysplasia (BPD) because no effective treatment exists. Mesenchymal stromal cell extracellular vesicles (MSC-sEVs) have therapeutic efficacy in a mouse pup neonatal hyperoxia BPD model. We tested the hypothesis that MSC-sEVs will improve lung functional and structural development in mechanically ventilated preterm lambs.

Postnatal growth restriction impairs rat lung structure and function.

The negative impact of nutritional deficits in the development of bronchopulmonary dysplasia is well recognized, yet mechanisms by which nutrition alters lung outcomes and nutritional strategies that optimize development and protect the lung remain elusive. Here, we use a rat model to assess the isolated effects of postnatal nutrition on lung structural development without concomitant lung injury. We hypothesize that postnatal growth restriction (PGR) impairs lung structure and function, critical mediators of lung development, and fatty acid profiles at postnatal day 21 in the rat.

Nucleated Red Blood Cell Emergence-Time in Newborn Lambs Following a Dose of Darbepoetin Alfa.

Background: Nucleated red blood cells (NRBC) are very uncommon in the blood of children and adults, but small numbers are not rare in neonates on the day of birth. Elevated NRBC counts in neonates can be seen following erythropoietin dosing. Limited studies in human neonates suggest the time-interval between erythropoietin dosing and the first appearance of NRBC in the blood (the "NRBC emergence-time") is in excess of 24 hours.

Pilot dose-ranging of rhIGF-1/rhIGFBP-3 in a preterm lamb model of evolving bronchopulmonary dysplasia.

Background: Low levels of insulin-like growth factor-1 (IGF-1) protein in preterm human infants are associated with bronchopulmonary dysplasia (BPD). We used our preterm lamb model of BPD to determine (1) dosage of recombinant human (rh) IGF-1 bound to binding protein-3 (IGFBP-3) to reach infant physiologic plasma levels; and (2) whether repletion of plasma IGF-1 improves pulmonary and cardiovascular outcomes.

Methods: Group 1: normal, unventilated lambs from 128 days gestation through postnatal age 5 months defined normal plasma levels of IGF-1.

Early extubation to noninvasive respiratory support of former preterm lambs improves long-term respiratory outcomes.

Invasive mechanical ventilation (IMV) and exposure to oxygen-rich gas during early postnatal life are contributing factors for long-term pulmonary morbidities faced by survivors of preterm birth and bronchopulmonary dysplasia. The duration of IMV that leads to long-term pulmonary morbidities is unknown. We compared two durations of IMV (3 h vs.

Non-invasive measurements of respiratory system mechanical properties by the forced oscillation technique in spontaneously breathing, mixed-breed, normal term lambs from birth to five months of age.

Objective: To provide a non-invasive approach to monitoring lung function in spontaneously breathing lambs, from birth to five months of life, by the forced oscillation technique (FOT). This report describes the experimental set-up, data processing, and identification of normal predicted values of resistance (Rrs) and reactance (Xrs) of the respiratory system, along with normal bronchodilator response for bronchial reversibility testing.

Approach: Rrs and Xrs at 5, 11, and 19 Hz were measured monthly for five months in 20 normal term lambs that breathed spontaneously.

Former-preterm lambs have persistent alveolar simplification at 2 and 5 months corrected postnatal age.

Preterm birth and mechanical ventilation (MV) frequently lead to bronchopulmonary dysplasia, the histopathological hallmark of which is alveolar simplification. How developmental immaturity and ongoing injury, repair, and remodeling impact completion of alveolar formation later in life is not known, in part because of lack of suitable animal models. We report a new model, using former-preterm lambs, to test the hypothesis that they will have persistent alveolar simplification later in life.