Circulating serum trefoil factors increase dramatically during pregnancy

Trefoil factors (TFF1-3) are 7-12 kDa peptides secreted by mucosal surfaces, with changing levels of expression reflected in serum concentrations. The genes for the peptides are located on chromosome 21, the chromosome duplicated in trisomy 21. We studied the levels of circulating TFFs in pregnant women carrying trisomy 21 foetuses and in women with normal pregnancies, throughout pregnancy and postpartum.

Employing ELISA methods, serum collected at gestational weeks (GW) 18, 32, 39 and 8 weeks postpartum from women carrying normal foetuses (n=141) was analysed for TFFs. In addition, serum collected at GW 6-14 (median = 10) from women carrying trisomy 21 foetuses (n=48) or healthy foetuses (n=46) was analysed.

Peaking at 39 GW, concentrations of TFF2 and TFF3 were 3.5 and 47 times higher, respectively, than postpartum. Postpartum levels were comparable to concentrations previously measured in nonpregnant women. TFF1 concentrations rose throughout pregnancy and postpartum, being 1.5 times higher postpartum compared to 18 GW. No differences in the levels of TFFs were observed between women carrying trisomy 21 and those with healthy foetuses. To our knowledge, circulating TFF3 has never been reported to reach the levels observed here. Also, the pattern of increase is unusual, as previous reports have shown parallel increases in TFF1 and TFF3 with no alterations in TFF2.

Our results demonstrate that circulating TFFs are not candidate markers of trisomy 21 in first-trimester pregnancies, but raise intriguing questions concerning the origin of TFFs produced during pregnancy and their physiological function.