Prepartum maturation of the lung in fetal sheep: relation to cortisol

Kitterman, Joseph A.; Liggins, G. C.; Campos, Guilherme; Clements, John A.; Forster, Christine S.; Lee, C. H.; Creasy, Robert K.

doi:10.1152/jappl.1981.51.2.384

Cited by 78 publications

(42 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Receptor data GUINEA PIG FETAL LUNG DEVELOPMENT 43 1 indicating an increase in the number of glucocorticoid receptors in fetal lung prior to the onset of surfactant production (24), plus adrenocorticoid ablation (25) or blocking studies (metyrapone) (21) demonstrating delays in surfactant maturation, add additional support for an endogenous glucocorticoid influence on surfactant development. Our findings of serum glucocorticoid peaks (cortisol and corticosterone) in the 59-day guinea pig, preceding the DSPC/PG rise beginning at day 6 1, are in agreement with studies from other species (23) and consistent with the guinea pig serum hormone data of Jones and Rolph (26). In addition to the role endogenous glucocorticoids may play in surfactant system maturation, there is good evidence in fetal sheep that morphologic lung development is also more closely related to fetal cortisol levels than to gestational age (23), suggesting this hormone may influence morphologic maturation as well.…”

Section: Discussionsupporting

confidence: 92%

“…Kitterman et al (23) determined that a closer correlation was present in fetal sheep between plasma cortisol and DSPC increase than between gestational age and rise in DSPC. Receptor data GUINEA PIG FETAL LUNG DEVELOPMENT 43 1 indicating an increase in the number of glucocorticoid receptors in fetal lung prior to the onset of surfactant production (24), plus adrenocorticoid ablation (25) or blocking studies (metyrapone) (21) demonstrating delays in surfactant maturation, add additional support for an endogenous glucocorticoid influence on surfactant development.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Lung Development in the Fetal Guinea Pig: Surfactant, Morphology, and Premature Viability

Sosenko

Frank

1987

Pediatr Res

View full text Add to dashboard Cite

ABSTRACT. Guinea pigs demonstrate "precocious" physical and functional development, with newborns displaying open eyes, hair, self-feeding, and temperature regulation. In addition, morphologic lung development is precocious in the guinea pig, with advanced alveolarization taking place in utero. To explore whether pulmonary surfactant development is also advanced, and at what stage prematurely delivered guinea pigs are capable of survival, we delivered fetal guinea pigs at 2-to 3-day intervals from day 49 of gestation to day 69 (birth). These were examined for chronologic changes in lung morphology, lung tissue disaturated phosphatidylcholine, phosphatidylglycerol and glycogen content, and serum glucocorticoid and thyroid hormone levels. Other prematurely delivered guinea pigs were given brief postnatal resuscitation and their survival noted. We confirmed advanced morphologic lung maturation, yet found that surfactant development, with antecedent hormone peaks and glycogen depletion, occurs during the final 10-15% of gestation. Lung biochemical development is thus "on time" in the guinea pig, rather than "precocious" compared to other frequently studied laboratory animals. In addition, >50% of fetal guinea pigs are capable of survival by 8 days prior to term, well in advance of premature survivability in other small-sized species. The gestation period of the guinea pig is considerably longer (69 days) than that of other commonly studied small-sized mammals (i.e hamster -16 days, rat -22 days, rabbit -31 days). Associated with this relatively long gestation in the guinea pig is a remarkable degree of physical and functional maturity demonstrated by the newborn of the species. At birth guinea pigs have full coats of hair, open eyes, and the ability to regulate body temperature and to feed apart from the mother (1). Engel (2) hypothesized in 1953 that the lung growth and development of a species should parallel the overall development present at birth. In support of Engel's hypothesis, Lechner and Banchero (3) Received Oct. 2, 1986; accepted Dec. 4, 1986 found advanced morphologic lung development in the newborn guinea pig.We questioned whether other aspects of lung development, in addition to lung morphology, would also be accelerated in the developing guinea pig, adding further support to Engel's hypothesis. The present study was undertaken to investigate the following: I ) the developmental pattern of the surfactant system in the fetal guinea pig, 2) how surfactant development is chronologically related to morphologic development in the guinea pig lung, 3) whether an endogenous rise or peak in serum glucocorticoid and/or thyroid hormone levels precedes the maturational changes in lung morphology and/or surfactant. Finally, we sought to determine the viability of premature guinea pigs delivered at varying gestational ages, and what degree of lung morphologic and surfactant development would be associated with premature survival. METHODSTimed-pregnancy Camm-Hartley guinea pigs were obtained from Camm Laboratories, ...

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Lung Development in the Fetal Guinea Pig: Surfactant, Morphology, and Premature Viability

Sosenko

Frank

1987

Pediatr Res

View full text Add to dashboard Cite

show abstract

“…Observations made in fetuses of 134 days or more showed significant differences in lung metabolism compared to younger animals. This is of interest because maturation of the lung in the sheep occurs at 134 to 135 days gestation as indicated by increased surfactant availability, disappearance of lung glycogen, and increase in lung distensibility (17)(18)(19)(20)(21).…”

Section: Discussionmentioning

confidence: 99%

Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Simmons

Charlton

1988

Pediatr Res

View full text Add to dashboard Cite

ABSTRACT. I n vivo substrate utilization has not been described for the maturing fetal lung. We, therefore, studied pulmonary delivery and use of major fetal substrates in six chronically catheterized fetal lambs over 119-141 days gestation. Oxygen, glucose, lactate, and a-amino nitrogen concentrations were measured in the pulmonary artery and pulmonary vein whereas lung blood flow was determined using labeled microspheres. We found that lung oxygen availability and use increased near term. 606Using the chronically catheterized fetal sheep model (6), we determined the availability of major fetal substrates to the developing lung and lung substrate utilization during the third trimester. Pulmonary delivery and uptake of oxygen, glucose, lactate, and a-amino nitrogen were followed over the last weeks of gestation, allowing us to define the changing pattern of pulmonary substrate availability and use that accompanies advancing gestation. METHODSSurgical preparation and recovery. Six mixed Western, breeddated, pregnant sheep of 1 15-125 days gestation were surgically prepared with indwelling catheters, using methods described previously (6). Six fetal lambs were catheterized, five singletons and one from a set of twins. Surgery was performed after the animals had fasted 24 h. Spinal anesthesia was induced with 2.0 ml of 1 % tetracaine hydrochloride and analgesia was provided with intravenous pentobarbital (65 mg/ml) as needed. Polyvinyl catheters (0.050 inch inner diameter and 0.090 inch outer diameter) were placed in the maternal femoral artery and vein. The uterus was then exposed through a midline abdominal incision and opened. Local anesthesia with 1% xylocaine was used for all fetal incisions; pentobarbital (5-10 mg/kg) and succinyl choline (1 mg/kg) were given as needed for fetal sedation and to minimize fetal movement. Catheters (0.030 inch inner diameter and 0.048 inch outer diameter) were inserted either into the fetal femoral artery and vein of one hindlimb (four animals) or into the carotid artery and jugular vein (two animals). The fetal chest was then exposed and a thoracic incision was made on the left side, from sternum to spine. The pleural space was entered through the fourth intercostal space and the lungs were gently retracted. The pericardium was opened and a 20-gauge Teflon catheter, fitted on a piece of polyvinyl tubing (7), was then placed into the main pulmonary artery. A catheter (0.01 1 inch inner diameter and 0.030 inch outer diameter) was inserted into a distal pulmonary vein and threaded up into a major vein draining the upper lobe of the left fetal lung. The fetal chest was then closed. A multipore amniotic fluid catheter was anchored in the uterus and the uterus was also sutured closed. All catheters were exteriorized through a stab wound in the maternal flank, where they were protected by a mesh pocket. At surgery, penicillin (1 million units) and kanamycin (200 mg) were given to the ewe intravenously and were also instilled into the amniotic cavity.After surgery the ewes were fed ad...

show abstract

“…To calculate phospholipid content, we measured phosphorus in an aliquot (5). SatPC was measured using the osmium tetroxide method (34) as previously described for fetal sheep lungs (30). Results are expressed as milligrams per gram of dry lung weight.…”

Section: Methodsmentioning

confidence: 99%

Effects of oligohydramnios on lung growth and maturation in the fetal rat

Kitterman

Chapin

Vanderbilt

et al. 2002

American Journal of Physiology-Lung Cellular and Molecular Phys

View full text Add to dashboard Cite

Oligohydramnios (OH) retards fetal lung growth by producing less lung distension than normal. To examine effects of decreased distension on fetal lung development, we produced OH in rats by puncture of uterus and fetal membranes at 16 days of gestation; fetuses were delivered at 21 or 22 days of gestation. Controls were position-matched littermates in the opposite uterine horn. OH lungs had lower weights and less DNA, protein, and water, but no differences in saturated phosphatidylcholine, surfactant proteins (SP)-A and -B, and mRNA for SP-A, -B, -C, and -D. To evaluate effects on epithelial differentiation, we used RTI 40 and RTII70, proteins specific in lung to luminal surfaces of alveolar type I and II cells, respectively. At 22 days of gestation, OH lungs had less RTI40 mRNA (P Ͻ 0.05) and protein (P Ͻ 0.001), but RTII70 did not differ from controls. With OH, type I cells (in proportion to type II cells) covered less distal air space perimeter (P Ͻ 0.01). We conclude that OH, which retards lung growth, has little effect on surfactant and impedes formation of type I cells relative to type II cells. fetal lung development; lung distension; pulmonary epithelial differentiation; pulmonary hypoplasia; pulmonary surfactant IN LATE GESTATION, the fetal lung undergoes marked changes in preparation for the transition to extrauterine life. These changes include growth, enlargement of distal potential air spaces, thinning of the septa, maturation of the surfactant system, and differentiation of distal pulmonary epithelium into mature alveolar type I and type II cells. Several studies have shown that fetal lung growth is controlled primarily by mechanical factors, especially distension of the lung (for reviews, see Refs. 26 and 29) and that maturation of the surfactant system is controlled primarily by endocrine factors (for reviews, see Refs. 3 and 48). In contrast, relatively little is known about factors that regulate differentiation of the alveolar epithelium.In 1977, Alcorn and associates (2) reported that tracheal ligation in fetal sheep, which increased lung distension, caused accelerated lung growth and a qualitative reduction in the number of alveolar type II cells; conversely, chronic drainage of tracheal fluid, which inhibited lung distension, retarded lung growth and increased the number of type II cells. However, they reported neither quantitative data for cell counts nor measurements of indicators of surfactant, which is produced by type II cells. Subsequently, other investigators have studied tracheal ligation in fetal sheep and have confirmed that an increase in lung distension results in a lower number of type II cells (6,11,37) and a higher percentage of type I cells (18). Tracheal ligation also results in lower concentrations in the lung of surfactant protein (SP)-A and saturated phosphatidylcholine (SatPC), the major surface-active lipid in pulmonary surfactant (28), as well as mRNA for SP-A, -B, and -C (32). Conversely, transection of the cervical spinal cord (which abolishes fetal breathing movemen...

show abstract

Prepartum maturation of the lung in fetal sheep: relation to cortisol

Cited by 78 publications

References 0 publications

Lung Development in the Fetal Guinea Pig: Surfactant, Morphology, and Premature Viability

Lung Development in the Fetal Guinea Pig: Surfactant, Morphology, and Premature Viability

Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Effects of oligohydramnios on lung growth and maturation in the fetal rat

Contact Info

Product

Resources

About