Host defense proteins in vernix caseosa and amniotic fluid

doi:10.1016/j.ajog.2004.05.002

American Journal of Obstetrics and Gynecology

Volume 191, Issue 6, December 2004, Pages 2090-2096

https://doi.org/10.1016/j.ajog.2004.05.002 Get rights and content

Objective

This study was undertaken to define the spectrum, activity, and spatial distribution of antimicrobial peptides in vernix caseosa and amniotic fluid in the absence of clinical chorioamnionitis.

Study design

Characterization of innate immune proteins in vernix and amniotic fluid obtained from pregnancies with gestational ages greater than 37 weeks by Western analysis, immunohistochemistry, and antimicrobial growth inhibition assay.

Results

Lysozyme, lactoferrin, human neutrophil peptides 1-3, and secretory leukocyte protease inhibitor were identified by Western analysis in vernix suspensions (n = 25) and amniotic fluid samples (n = 10). Three other important antimicrobial proteins, human beta defensin-2, lactoperoxidase, and LL-37 were not detected. Amniotic fluid and soluble extracts of vernix exhibited muramidase (lysozyme) activity, and there was selective efficacy in inhibiting growth of common perinatal pathogens. Antimicrobial peptides were concentrated in discrete, organized, acellular “granules” embedded in the vernix lipid matrix.

Conclusion

In the absence of chorioamnionitis, vernix and amniotic fluid contain an organized pool of antimicrobial peptides with a defined spectrum of bioactivity against common bacterial and fungal pathogens.

Section snippets

Sample collection

Sample collection protocol was approved by the Institutional Review Board of The Christ Hospital, Cincinnati, Ohio. All pregnant women admitted for elective cesarean section without prior labor between June 2001 and September 2002 who consented to the study were enrolled. Vernix samples were obtained from infants delivered to women admitted for elective cesarean section without prior labor. Amniotic membranes were intact at the time of admission and gestational age was greater than 37 weeks.

Demographic characteristics of patients

The mean age of enrolled pregnant women was 30.5 ± 4.8. Mean gestational age was 39 ± 1.8 weeks after conception as determined by best obstetric estimate from early gestation ultrasound, and/or last menstrual period assessment. The median parity was 3. The mean birth weight of a newborn infant in the current study was 3.58 ± 0.62 kg. The median 5-minute Apgar score was 9. The time interval between amniocentesis and delivery was 28.6 ± 14.2 hours.

Protein content of vernix

The yield of vernix per infant was 10.0 ± 2.4 g.

Comment

The current study identifies a redundant system of innate immune molecules present in uninfected amniotic fluid and vernix caseosa. These bioactive antimicrobial peptides are available to respond to intra-amniotic infection. Understanding mechanisms of innate immune function in late gestation should aid in development of treatment strategies for earlier periods. More than 50% of fetuses delivered before 30 weeks' gestation have clinical or bacteriologic evidence of chronic chorioamnionitis.¹²

Acknowledgments

We thank Dr Susan Wert for suggestions regarding immunohistochemistry and Dr Edward Donovan for reading the manuscript.

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: Supported by grant AI50797 from the National Institutes of Health.

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General Obstetrics and Gynecology: ObstetricsHost defense proteins in vernix caseosa and amniotic fluid

Objective

Study design

Results

Conclusion

Section snippets

Sample collection

Demographic characteristics of patients

Protein content of vernix

Comment

Acknowledgments

J Investig Dermatol

Microbes Infect

J Biol Chem

Int J Gynaecol Obstet

Placenta

Am J Obstet Gynecol

J Invest Dermatol

Curr Opin Immunol

Am J Obstet Gynecol

The biology of vernix

Antimicrobial peptides in amniotic fluid: defensins calprotectin and bacterial/permeability-increasing protein in patients with microbial invasion of the amniotic cavity, intra-amniotic inflammation, preterm labor and premature rupture of membranes

J Matern Fetal Neonatal Med

General Obstetrics and Gynecology: Obstetrics
Host defense proteins in vernix caseosa and amniotic fluid