Objective: We conducted a comparative proteomic analysis of placental and umbilical cord blood proteins using surface-enhanced laser desorption ionization-time of flight mass spectrometry (SELDI-TOF MS) to examine the associations among asthma, fetal gender, and protein profiles.
Methods: Placental tissue and umbilical vein plasma were collected from 10 healthy and 20 asthmatic women. Placental proteins were extracted using phosphate-buffered saline containing protease inhibitors. Samples were applied to the surfaces of strong anion exchange (SAX2), weak cation exchange (WCX2) and immobilized metal affinity capture (IMAC-Cu(2+)) chips. Mass analysis was conducted using a Ciphergen Protein Biology System IIc (Freemont, CA), and differences in individual peak intensities between groups were determined.
Results: Fourteen placental peaks were significantly different between asthmatic and non-asthmatic women (seven more highly expressed and seven less highly expressed). Ten umbilical cord blood peak differences were identified, with four peaks more highly expressed and six peaks less highly expressed in asthmatics. Four placental and three umbilical cord blood proteins differed significantly between male and female fetuses. Two placental and five umbilical cord blood peaks were specifically increased in a subgroup of samples collected from asthmatic women who did not use inhaled glucocorticoids and were pregnant with a female fetus, a group previously found to have altered placental function.
Conclusions: This study demonstrates the abilities of the SELDI technique as a tool for protein profiling in tissue or plasma. Further work to positively identify the candidate peptides found in this study may provide a greater understanding of the placental mechanisms leading to alterations in fetal growth in patients with bronchial asthma.