[Frontiers in Bioscience E3, 291-300, January 1, 2011]

Surfactant proteins A and D in pregnancy and parturition

Ajit Kumar Yadav1, Taruna Madan1, Andres Lopez Bernal2

1National Institute for Research in Reproductive Health, Mumbai, India, 2University of Bristol, School of Clinical Sciences, Obstetrics and Gynaecology, Bristol, UK


1. Abstract
2. Introduction
3. Structure of SP-A and SP-D
4. Localisation of surfactant proteins in female reproductive tract
5. SP-A and SP-D in amniotic fluid and amniotic epithelium
6. Role of SP-A and SP-D in host defense of the female reproductive tract
7. SP-A and SP-D in pregnancy maintenance
7.1.Role of SP-A in parturition
7.2.Mechanisms underlying SP-A mediated induction of parturition
7.3.Inhibition of SP-A to delay pre-term labor?
7.4.SP-A, SP-D and matrix metalloproteinases
7.5.Modulation of the adaptive immune response by SP-A and SP-D
7.6. Alteration of SP-A and SP-D function by post-translational modification
5. Inference
6. Acknowledgment
7. References


Surfactant proteins A and D have extra-pulmonary expression at various mucosal sites including the reproductive tract. Reproductive tissues require a fine immune balance, strong enough to keep infection at a bay and at the same time, subtle enough to support an allogeneic fetus throughout the pregnancy. Roles of SP-A and SP-D have been studied in depth and include immunoregulatory function, besides strengthening the innate immune system against various pathogens in the lungs. Interestingly, levels of SP-A and SP-D in the amniotic fluid increase progressively in pregnancy. SP-A has been implicated in the induction of parturition. The present review elaborates the plausible roles of SP-A and SP-D in pregnancy maintenance and future applications.