Little is known about the effects of fetal ethanol exposure on lung development. Our aim was to determine the effects of repeated ethanol exposure during late gestation on fetal lung growth, maturation, and inflammatory status. Pregnant ewes were chronically catheterized at 91 days of gestational age (DGA; term ϳ147 days). From 95-133 DGA, ewes were given a 1-h daily infusion of either 0.75 g ethanol/kg (n ϭ 9) or saline (n ϭ 8), with tissue collection at 134 DGA. Fetal lungs were examined for changes in tissue growth, structure, maturation, inflammation, and oxidative stress. Between treatment groups, there were no differences in lung weight, DNA and protein contents, percent proliferating and apoptotic cells, tissue and air-space fractions, alveolar number and mean linear intercept, septal thickness, type-II cell number and elastin content. Ethanol exposure caused a 75% increase in pulmonary collagen I ␣1 mRNA levels (P Ͻ 0.05) and a significant increase in collagen deposition. Surfactant protein (SP)-A and SP-B mRNA levels were approximately one third of control levels following ethanol exposure (P Ͻ 0.05). The mRNA levels of the proinflammatory cytokines interleukin (IL)-1␤ and IL-8 were also lower (P Ͻ 0.05) in ethanol-exposed fetuses compared with controls. Pulmonary malondialdehyde levels tended to be increased (P ϭ 0.07) in ethanolexposed fetuses. Daily exposure of the fetus to ethanol during the last third of gestation alters extracellular matrix deposition and surfactant protein gene expression, which could increase the risk of respiratory distress syndrome after birth. Changes to the innate immune status of the fetus could increase the susceptibility of the neonatal lungs to infection.

Preterm birth affects 8-10% of human pregnancies and is a major cause of long-term disability. Individuals who are born very preterm, especially if they develop bronchopulmonary dysplasia (BPD), have an increased risk of impaired lung function in infancy, childhood and adulthood, as well as an increased risk of respiratory illness. Our aim is to briefly review current understanding of the basis for long-term impairments in lung function and respiratory health following preterm birth and BPD. Histopathology of the lungs of infants and children following preterm birth and BPD shows altered development of the lung parenchyma, conducting airways and pulmonary vasculature. Owing to improvements in the care of preterm infants, especially the use of exogenous surfactant and lower concentrations of administered oxygen, lung pathology following preterm birth and BPD is less severe than in the past. Recent studies indicate that very preterm birth and BPD can lead to hyperplasia of airway smooth muscle, impaired alveolarization, pulmonary inflammation and an increase in pulmonary artery muscularization. Imaging of adult lungs suggests that the deficit in alveoli can persist into later life. Long-term lung injury apparently relates to the use of mechanical ventilation and the use of supplemental oxygen in infancy. Impaired lung function in later life is due to airway hyper-reactivity and fewer alveoli, resulting in reductions in the surface area for gas exchange and physical support for bronchioles. Because the incidence of preterm birth is not declining, it will continue to be a major cause of respiratory ill-health in adults.

Harding R, Black MJ. Alcohol exposure during late gestation adversely affects myocardial development with implications for postnatal cardiac function. Am J Physiol Heart Circ Physiol 300: H645-H651, 2011. First published November 12, 2010 doi:10.1152/ajpheart.00689.2010.-Prenatal exposure to high levels of ethanol is associated with cardiac malformations, but the effects of lower levels of exposure on the heart are unclear. Our aim was to investigate the effects of daily exposure to ethanol during late gestation, when cardiomyocytes are undergoing maturation, on the developing myocardium. Pregnant ewes were infused with either ethanol (0.75 g/kg) or saline for 1 h each day from gestational days 95 to 133 (term ϳ145 days); tissues were collected at 134 days. In sheep, cardiomyocytes mature during late gestation as in humans. Within the left ventricle (LV), cardiomyocyte number was determined using unbiased stereology and cardiomyocyte size and nuclearity determined using confocal microscopy. Collagen deposition was quantified using image analysis. Genes relating to cardiomyocyte proliferation and apoptosis were examined using quantitative real-time PCR. Fetal plasma ethanol concentration reached 0.11 g/dL after EtOH infusions. Ethanol exposure induced significant increases in relative heart weight, relative LV wall volume, and cardiomyocyte cross-sectional area. Ethanol exposure advanced LV maturation in that the proportion of binucleated cardiomyocytes increased by 12%, and the number of mononucleated cardiomyocytes was decreased by a similar amount. Apoptotic gene expression increased in the ethanol-exposed hearts, although there were no significant differences between groups in total cardiomyocyte number or interstitial collagen. Daily exposure to a moderate dose of ethanol in late gestation accelerates the maturation of cardiomyocytes and increases cardiomyocyte and LV tissue volume in the fetal heart. These effects on cardiomyocyte growth may program for long-term cardiac vulnerability.

In most species including man, cardiomyocytes cease proliferating soon after birth when they become terminally differentiated. A reduced complement of cardiomyocytes in infancy may adversely impact on the function and adaptive capabilities of the heart in later life. Low birthweight is associated with an increased risk of heart disease in adults, but little is known about its effect on the number of cardiomyocytes. Using naturally occurring differences in birthweight, our aim was to determine the effect of birthweight on cardiomyocyte number in postnatal lambs. At 9 weeks after term birth, when the final number of cardiomyocytes is considered to be established, hearts were collected at necropsy from seven singleton and seven twin lambs. Hearts were perfusion-fixed, and tissue samples were systematically taken from the left ventricle plus intraventricular septum (LV1S) and the right ventricle (RV). The number of cardiomyocyte nuclei was estimated using an unbiased optical disector-fractionator stereological technique, and the total number of cardiomyocytes was determined. Weights of the total heart, LV1S and RV were significantly related to both birthweight and necropsy weight. In the LV1S but not the RV, cardiomyocyte number was significantly and directly related to heart tissue weight, birthweight, and necropsy weight. We conclude that the final number of cardiomyocytes in the LV1S is related to prenatal and early postnatal growth, and is proportionate to the weight of heart tissue. A low cardiomyocyte number in the LV1S following restricted fetal growth may contribute to the increased incidence of heart disease in adults born with low birthweight.

High levels of ethanol (EtOH) consumption during pregnancy adversely affect fetal development; however, the effects of lower levels of exposure are less clear. Our objectives were to assess the effects of daily EtOH exposure (3.8 USA standard drinks) on fetal-maternal physiological variables and the fetal brain, particularly white matter. Pregnant ewes received daily intravenous infusions of EtOH (0.75 g/kg maternal body wt over 1 h, 8 fetuses) or saline (8 fetuses) from 95 to 133 days of gestational age (DGA; term ∼145 DGA). Maternal and fetal arterial blood was sampled at 131-133 DGA. At necropsy (134 DGA) fetal brains were collected for analysis. Maternal and fetal plasma EtOH concentrations reached similar maximal concentration (∼0.11 g/dl) and declined at the same rate. EtOH infusions produced mild reductions in fetal arterial oxygenation but there were no changes in maternal oxygenation, maternal and fetal Pa(CO(2)), or in fetal mean arterial pressure or heart rate. Following EtOH infusions, plasma lactate levels were elevated in ewes and fetuses, but arterial pH fell only in ewes. Fetal body and brain weights were similar between groups. In three of eight EtOH-exposed fetuses there were small subarachnoid hemorrhages in the cerebrum and cerebellum associated with focal cortical neuronal death and gliosis. Overall, there was no evidence of cystic lesions, inflammation, increased apoptosis, or white matter injury. We conclude that daily EtOH exposure during the third trimester-equivalent of ovine pregnancy has modest physiological effects on the fetus and no gross effects on fetal white matter development.