Preeclampsia is a common pregnancy-specific syndrome that is diagnosed by the appearance of both increased blood pressure and
proteinuria.
Preeclampsia is associated with significant fetal and maternal morbidity and mortality. Although the etiology of
preeclampsia is unknown, it is evident that abnormal placentation and trophoblast metabolism plays an important role. We therefore analyzed, identified, and verified specific
proteins of villous trophoblast and villous stroma in small numbers of microdissected cells (approximately 125 cells) from seven placentas of women with pregnancies complicated by
preeclampsia (cases) and seven uncomplicated pregnancies (controls). Tryptic
peptide profiling by MALDI-TOF MS was used for comparison and identification of significantly expressed
peptides. The data were analyzed by ClinProTools (Bruker Daltonics) and by principal component analysis. Subsequently, a subset of placental tissues were homogenized and separated on a NanoLC system to obtain sequencing information (MS/MS spectra). We identified specific
peptide patterns in the different cell types: villous stroma and trophoblast cells and differences in these cells of placentas from women with pregnancies complicated by early compared to late onset
preeclampsia (<34 and >34 wk gestation, respectively) and controls. Principal component analysis revealed significant differences between the groups. The comparison with placental tissue after preterm delivery with unknown cause revealed that placental
peptide patterns in early onset
preeclampsia could not be explained by preterm delivery per se. Subsequently, specific, discriminating
proteins for early onset
preeclampsia compared to controls were identified including
calcyclin, surfeit locus
protein, and
choriomammotropin A precursor. The expression of
calcyclin was verified in early onset preeclamptic placental sections by immunohistochemistry. These data suggest that in early onset
preeclampsia trophoblastic
choriomammotropin regulation is abnormal, possibly through abnormal
calcyclin expression and regulation.