PlGF isoform 3 in maternal serum and placental tissue.

OBJECTIVES: Four isoforms originating from alternative splicing of PGF gene have been reported for placental growth factor (PlGF). Main PlGF isoforms 1 and 2 have been associated with screening and diagnosis of pre-eclampsia (PE). Despite of the vast amount of research around PlGF in PE, protein levels of isoforms PlGF-3 and -4 have not been reported in human serum samples. STUDY DESIGN: In this study a PlGF-3 specific DELFIA research immunoassay based on a custom recombinant Fab binder was developed and characterized. Serum levels of a third PlGF isoform during pregnancy were determined and screening performance of PlGF-3 for PE and small for gestational age (SGA) was investigated. MAIN OUTCOME MEASURES: Levels of serum and placental tissue PlGF 3 and predictive power of PlGF-3 for Pre-eclampsia and SGA. RESULTS: PlGF-3 was below the detection limit of 1.6 pg/mL in most of the serum samples collected during pregnancy. Detected protein levels of PlGF-3 were not associated to be predictive for PE or SGA. However, measurable, and relatively higher amounts of PlGF-3 was extracted from placental tissue samples. CONCLUSION: Data obtained indicates that very low amounts of PlGF-3 is present in blood but significantly higher amounts of protein is present in placental tissue where it is prominently associated with cellular membranes.