BACKGROUND: We have recently shown that moderate preterm birth, in the absence of respiratory support, altered the structure of lung parenchyma in young lambs, but the long-term effects are unknown. OBJECTIVES: To determine whether structural changes persist to maturity, and whether postnatal growth affects lung structure at maturity in sheep. METHODS: At approximately 1.2 years after birth, lung parenchyma of sheep born 14 days before term (n = 7) was stereologically compared with that of controls born at term (n = 8, term approx. 146 days). RESULTS: Preterm birth per se had no significant effect on lung volume, alveolar number and size, and thicknesses of the alveolar walls and blood-gas barrier. After combining the preterm and term groups, we examined the effects of postnatal growth rates on lung parenchyma. Slower-growing sheep (SG; n = 7: 4 preterm, 3 term) were compared with faster-growing sheep (FG; n = 8: 3 preterm, 5 term). At approximately 1.2 years, the right lung volume, relative to body weight, was significantly lower in SG than FG sheep (p < 0.05) and alveolar number was significantly lower by approximately 44%. The total alveolar internal surface area of the right lung of SG sheep was 38% smaller than in FG sheep; it was also significantly lower when related to both lung and body weight. CONCLUSIONS: Our data suggest that moderate preterm birth does not cause persistent alterations in lung parenchyma. However, slow postnatal growth in low-birth-weight sheep results in smaller lungs with fewer alveoli and a lower alveolar surface area relative to body weight. Copyright (c) 2007 S. Karger AG, Basel.
BACKGROUND: We have recently shown that moderate preterm birth, in the absence of respiratory support, altered the structure of lung parenchyma in young lambs, but the long-term effects are unknown. OBJECTIVES: To determine whether structural changes persist to maturity, and whether postnatal growth affects lung structure at maturity in sheep. METHODS: At approximately 1.2 years after birth, lung parenchyma of sheep born 14 days before term (n = 7) was stereologically compared with that of controls born at term (n = 8, term approx. 146 days). RESULTS: Preterm birth per se had no significant effect on lung volume, alveolar number and size, and thicknesses of the alveolar walls and blood-gas barrier. After combining the preterm and term groups, we examined the effects of postnatal growth rates on lung parenchyma. Slower-growing sheep (SG; n = 7: 4 preterm, 3 term) were compared with faster-growing sheep (FG; n = 8: 3 preterm, 5 term). At approximately 1.2 years, the right lung volume, relative to body weight, was significantly lower in SG than FG sheep (p < 0.05) and alveolar number was significantly lower by approximately 44%. The total alveolar internal surface area of the right lung of SG sheep was 38% smaller than in FG sheep; it was also significantly lower when related to both lung and body weight. CONCLUSIONS: Our data suggest that moderate preterm birth does not cause persistent alterations in lung parenchyma. However, slow postnatal growth in low-birth-weight sheep results in smaller lungs with fewer alveoli and a lower alveolar surface area relative to body weight. Copyright (c) 2007 S. Karger AG, Basel.
Authors: Anne B Chang; Keith Grimwood; Andrew V White; Carolyn Maclennan; Theo P Sloots; Alan Sive; Gabrielle B McCallum; Ian M Mackay; Peter S Morris Journal: Trials Date: 2011-04-14 Impact factor: 2.279
Authors: Anne B Chang; Robyn L Marsh; John W Upham; Lucas R Hoffman; Heidi Smith-Vaughan; Deborah Holt; Maree Toombs; Catherine Byrnes; Stephanie T Yerkovich; Paul J Torzillo; Kerry-Ann F O'Grady; Keith Grimwood Journal: Front Pediatr Date: 2015-02-13 Impact factor: 3.418
Authors: Anne B Chang; John W Upham; I Brent Masters; Gregory R Redding; Peter G Gibson; Julie M Marchant; Keith Grimwood Journal: Pediatr Pulmonol Date: 2015-12-04