Overproduction of the follistatin-related gene protein in the placenta and maternal serum of women with pre-eclampsia.

OBJECTIVE

To characterise the follistatin-related gene (FLRG) in pre-eclampsia, one of the differentially expressed genes in pre-eclamptic placenta.

DESIGN AND METHODS

We examined and compared the messenger RNA (mRNA) and protein levels of FLRG in placentas and maternal sera from women with uncomplicated pregnancy, and those with pre-eclampsia using real-time reverse transcription polymerase chain reaction, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assay.

SETTING

Antenatal clinics in a teaching hospital.

POPULATION

Women with uncomplicated pregnancy (n = 21) and those with pre-eclampsia (n = 21).

RESULTS

FLRG mRNA is overexpressed in pre-eclamptic placental tissues (P < 0.01). Upregulated FLRG protein consists of both an immature 28-kDa cellular product and a mature 33-kDa secretory form, which are differentially glycosylated. FLRG is normally produced at its highest levels in endothelial cells and at moderate amounts in syncytiotrophoblast cells, but in pre-eclampsia, the syncytiotrophoblast FLRG levels are dramatically increased. We also determined the maternal serum concentrations of FLRG in our uncomplicated pregnancy subjects and in our pre-eclamptic groups, and found that they are significantly elevated in pre-eclampsia in a similar manner to activin A and inhibin A. However, the increase in FLRG in these cases is independent of activin A or inhibin A, and is associated with low-birthweight outcomes.

CONCLUSION

Our current data show the placental and secretory changes of FLRG protein in pre-eclampsia, and also indicate the potential usefulness of FLRG as an additional diagnostic marker for pre-eclampsia.