Prolongation of renal allograft survival in the rat treated with amniotic fluid

Amniotic fluid and maternal race influence responsiveness of fetal membranes to bacteria

Spontaneous preterm birth (PTB) and preterm prelabor rupture of membranes (pPROM) occur more frequently in African-American women than in other racial groups. This may be due to an enhanced inflammatory response to pathogens associated with the condition. It is also possible that amniotic fluid (AF) has different immunomodulatory properties in African-American women that increase their risk of PTB and pPROM. To test this, we cultured fetal membranes from European-American and African-American women with sterile medium (control), Escherichia coli, Gardnerella vaginalis, Group B streptococci (GBS), Polyporphorans gingivalis, Mycoplasma hominis, Ureaplasma urealyticum or Ureaplasma parvum in the presence and absence of 50% autologous AF. Cytokine concentrations were quantified in the conditioned medium. All bacterial species increased IL-8 production. IL-1β and TNF-α production were stimulated by LPS, E. coli, and G. vaginalis compared with control, but responses to Group B streptococci and P. gingivalis were limited to IL-1β and TNF-α respectively. Genital mycoplasmas stimulated TNF-α and IL-10 but had no effect on IL-1β production. African-Americans had twice the IL-1β response to E. coli as European-Americans (P=0.031). Conversely, European-Americans produced more IL-8 in response to LPS than African-Americans (P=0.026). AF had both pro- and anti-inflammatory properties that varied between races and pathogens. These results suggest that the host response to fetal membrane infections is complex and not generalizable. Interventions to prevent PTB and pPROM may need to be customized based on a patient's race, type of bacterial infection and factors in her AF.

The immunomodulatory activity of human amniotic fluid can be correlated with transforming growth factor-beta 1 (TGF-beta 1) and beta 2 activity

The role of alphafetoprotein (AFP) in the immunomodulatory activity of amniotic fluids (AF) from normally progressing human pregnancy (weeks 14-16) was investigated. A panel of 42 AF (25% v/v) reduced significantly phytohaemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMC) proliferation in serum-free cultures with a mean per cent inhibition of 68.4 +/- 5.5%. In contrast, AFP preparations, with one exception (U.AFP), failed to display inhibitory activity. Pretreatment of AF with anti-TGF-beta 1 and beta 2 antibodies used alone resulted in the mean per cent loss of inhibition of 33.1 +/- 3.9% and 52.3 +/- 7.5%, respectively. A summative loss of AF-mediated inhibition was detected when anti-TGF-beta 1 and beta 2 antibodies were used in combination, but immunomodulation was rarely abolished 100% by this treatment. Anti-TGF-beta 2 antibody treatment, unlike anti-TGF-beta 1 antibody treatment, reversed the inhibitory activity of U.AFP. The amount of TGF-beta 1 and beta 2 contained in human AF was studied by growth inhibition of Mv1 Lu cells. The mean levels of TGF-beta 1 and beta 2 in AF were 11 +/- 0.9 U/ml and 2.3 +/- 0.4 U/ml, respectively, which corresponds with a mean per cent inhibition of 49 +/- 4.7%. U.AFP also significantly inhibited Mv1 Lu cell growth. To investigate the mechanism of AF-mediated inhibition, the effect of AF and AFP on IL-2 production by concanavalin A (Con A)-stimulated PBMC blasts was determined by the CTLL-2 cell bioassay. IL-2 production was reduced 55.5% in AF-treated blasts and 61% in U.AFP-treated blasts compared with controls. Our findings indicate that the immunomodulatory activity of human AF can be correlated with TGF-beta 1 and beta 2 and not with AFP, the inhibitory activity of U.AFP preparation reflecting copurifying TGF-beta 2 activity.

Detection of complex gangliosides in human amniotic fluid

Gangliosides are possibly very potent immunosuppressive molecules. Here we show that human amniotic fluid contains high concentrations of a number of previously unnoted, structurally complex and highly polar gangliosides. These unusual molecules are present early in pregnancy (first trimester), increase in concentration with gestational age, and reach maximum levels (0.8 microM) at term. Since similar gangliosides have been detected in human placenta, trophoblast, and amnion, we suggest that these molecules are shed into the amniotic fluid bathing these tissues.