A proteomic approach to early prenatal screening has recently been published in Scientific Reports. The study, which details protein enrichment and quantification procedures, aims to profile any physiological/pathological changes that affect the growing embryo and mother. Among the findings produced by the method is the determination of the fetal sex. The work comes from a team led by the University of Calabria and Laboratory of Rare Diseases Molecular Diagnosis in Italy.
Coelomic fluid (CF) is the earliest fluid of the gestational sac and is in direct contact with the placenta during the first trimester, or first twelve weeks, of pregnancy. CF has also been used in early genetic screening. The team thus sought to determine if CF—like amniotic fluid—may also be used in prenatal screening.
The team recruited women who were in between 7-10 weeks of pregnancy. Twenty-two samples of CF were collected, which were further purified to yield CF cells and CF fluid. The cells were used for morphological and genetic analysis, while the fluid was used for proteomic analyses. A complete protocol that described protein purification methods was detailed in the study.
“The aim was to establish a differential proteomic expression profile of CF via a shotgun proteomic workflow,” the team reported. “The iTRAQ-MARS was established as the most efficient approach among those tested, and provided the identification and quantitation of 88 unique embryonic proteins.”
MARS (Multiple Affinity Removal Spin) enabled depletion of high abundant proteins prior to protein quantification by iTRAQ (isobaric tags for relative and absolute quantitation)-based MS/MS. It was noted that the presence of abundant serum proteins was a crucial barrier to overcome. In the end, the team was able to identify proteins that may then be associated with known disease pathways.
“It is worthy of note that literature reports realistic associations between specific diseases recognized by maternal serum/plasma or amniotic fluid diagnostics and several proteins detected and quantified by our iTRAQ-MARS protocol,” the team said.
Among the team’s list of quantified proteins was the chromosome X protein CXorf23, which may identify the fetal sex. Further analyses using quantitative fluorescent polymerase chain reaction (QF-PCR) on coelomic cells and fetal tissues resulted in a 100% concordance rate with the proteomic data.
The team concluded that, in addition to determining sex, functional associations may be possible in therapeutic areas of nervous, respiratory, eye and head system diseases.