Maternal alcohol ingestion reduces surfactant protein A expression by preterm fetal lung epithelia

Abstract

In addition to neurodevelopmental effects, alcohol consumption at high levels during pregnancy is associated with immunomodulation and premature birth. Premature birth, in turn, is associated with increased susceptibility to various infectious agents such as Respiratory Syncytial Virus (RSV). The initial line of pulmonary innate defense includes the mucociliary apparatus, which expels microorganisms trapped within the airway secretions. Surfactant proteins A and D (SP-A and SP-D, respectively) are additional components of pulmonary innate immunity and have an important role in pulmonary defense against inhaled pathogens. The purpose of this study was to determine if chronic alcohol consumption during the third trimester of pregnancy alters the function of the mucociliary apparatus and expression of SP-A and SP-D of fetal lung epithelia. Sixteen, date-mated ewes were assigned to two different groups; an ethanol exposed group in which ewes received ethanol through surgically implanted intra-abomasal cannula during the third trimester of pregnancy, and a control group in which ewes received the equivalent amount of water instead of ethanol. Within these two groups, ewes were further randomly assigned to a full-term group in which the lambs were naturally delivered, and a pre-term group in which the lambs were delivered prematurely via an abdominal incision and uterotomy. Ethanol was administered 5 times a week as a 40% solution at 1gr/kg of body weight. The mean maternal serum alcohol concentration (SAC) measured 6 hr post administration was 16.3 +/− 4.36 mg/dL. Tracheas from 6 full-term lambs were collected to assess ciliary beat frequency (CBF). The lung tissue from all (24) lambs was collected for immunohistochemistry (IHC) analysis of SP-A and SP-D protein production and fluorogenic realtime quantitative polymerase chain reaction analysis (qPCR) of SP-A and SP-D mRNA levels. Exposure to ethanol during pregnancy significantly blocked stimulated increase in CBF though ethanol-mediated desensitization of cAMP-dependant protein kinase (PKA). In addition, pre-term born/ethanol-exposed lambs showed significantly decreased SP-A m-RNA expression when compared to the pre-term born/control group (p=0.004); no significant changes were seen with SP-D. The full-term/ethanol exposed lambs had no significant alterations in mRNA levels, but had significantly less detectable SP-A protein when compared to the full-term/control lambs (p=0.02).Corresponding author: Tatjana Lazic, DVM, MS, 2740 Veterinary Medicine, Department of Veterinary Pathology, Iowa State University, Ames, Iowa 50011-1250, 515-294-6688, FAX 515-294-5423, tlazic@iastate.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process error...

Repeated ethanol exposure during late gestation alters the maturation and innate immune status of the ovine fetal lung

“…Our findings are in agreement with a recent study in sheep that showed that prenatal ethanol exposure decreases SP-A mRNA and protein levels (36). That study also demonstrated that prenatal ethanol exposure inhibits stimulated tracheal ciliary beat frequency, which is a protective mechanism required to remove foreign particles from the lungs (36). These findings are consistent with other studies that show that ethanol has an overall immunosuppressive effect (17,(22)(23)(24)27).…”

“…SP-A and SP-D can bind and opsonize microorganisms and, therefore, can have an important role in the lung's primary defense against inhaled pathogens, as well as being an important component of the innate immune response of the lungs. Our findings are in agreement with a recent study in sheep that showed that prenatal ethanol exposure decreases SP-A mRNA and protein levels (36). That study also demonstrated that prenatal ethanol exposure inhibits stimulated tracheal ciliary beat frequency, which is a protective mechanism required to remove foreign particles from the lungs (36).…”

SPUD qPCR Assay Confirms PREXCEL-Q Software's Ability to Avoid qPCR Inhibition

“…In summary, these fi ndings support our claim that PREXCEL-Q-calculated nucleic acid sample and standard dilutions for qPCR, based on the "Stock I approach" (Grubor et al, 2004;Gallup et al, 2005;Gallup et al, 2006;Kawashima et al, 2006;Lazic et al, 2007;Gallup et al, 2008;Olivier et al, 2009;Sponseller et al, 2009), avoids qPCR inhibitory behavior in all fi nal reactions (Gallup et al, 2008;. Because of this and other aspects, we recommend the use of PREXCEL-Q in all laboratories performing qPCR of any kind.…”

“…PREXCEL-Q is a qPCR software program that, among its other functions, identifies dilution parameters for all samples and standards that avoid qPCR-inhibitory phenomena. The SPUD assay was thus used in this study to critically test and corroborate the reported ability of the PREXCEL-Q program to avoid inhibition in qPCR samples and standards (Grubor et al, 2004;Gallup et al, 2005;Gallup et al, 2006;Kawashima et al, 2006;Lazic et al, 2007;Gallup et al, 2008;Olivier et al, 2009;Sponseller et al, 2009). …”

Effects of prenatal ethanol exposure on the lungs of postnatal lambs

“…Studies in rodents have also shown that exposure to high levels of ethanol in midgestation (41) or throughout pregnancy (23) decreases fetal lung growth. In contrast, exposure to a moderate level of ethanol during the later stages of gestation in sheep, when structural and functional maturation of the lungs occurs, does not alter fetal lung growth (37), although collagen deposition in the fetal lungs is increased and surfactant protein (SP) levels are reduced (28,37).…”