Activin A exerts both pro- and anti-inflammatory effects on human term gestational tissues

There is a growing appreciation of the importance of activin as a modulator of immune function. The aim of the present study was to determine whether activin A exerts any effects on cytokine and prostaglandin (PG) production by the tissues of pregnancy. Explant cultures were established for amnion, choriodecidual and placental tissues derived from pregnancies delivered at term by Caesarean section (n=5 placentae). Explants were treated with activ in A (0.5, 5 and 50 ng/ml) in serum-free Ham's F12/DME media for 24h (n=3-4 replicates). Production rates of interleukin (IL)-1 beta, IL-6, IL-8, tumo ur necrosis factor-alpha (TNF-alpha) and PGE(2) were determined using immun oassay. Differences between treatment groups were analysed by ANOVA followe d by Dunnett's test; P<0.05 was considered to be significant. Amnion IL-6 p roduction exhibited biphasic responses to activin A: at 5 ng/ml activin A, LT;a production was significantly stimulated to 246 +/-. 74.6 per cent of c ontrol (mean +/- SEM), while at 50 ng/ml it was significantly inhibited (to 46 +/- 7.4 per cent of control). IL-8 and PGE2 production by amnion showed significant responses to activin A that were similar to those of IL-6. No significant effects of activin A were observed on choriodecidual and placen tal IL-6, IL-8 and PGE(2) production. However, TNF-alpha production was sig nificantly inhibited by 50 ng/ml activin A in both choriodecidual and place ntal explants (to 43 +/- 9.7 per cent and 51 +/- 6.7 per cent of control, r espectively). Placental IL-1 beta production was not altered by treatment w ith activin A at any concentration. These findings support: the concept of activin as an immune modulator in tissues of pregnancy. (C) 2000 Harcourt P ublishers Ltd.