Effect of betamethasone in vivo on placental adrenomedullin in human pregnancy

Changes in adrenomedullin in bronchoalveolar lavage fluid with chorioamnionitis in a sheep-based model

BACKGROUND

Adrenomedullin (AM) is a potent angiogenic, antioxidant and anti-inflammatory peptide protecting the developing lung from injury due to bronchopulmonary dysplasia (BPD) of the preterm infant. At this stage, no data on the potential effects of chorioamnionitis (CA) occurrence and glucocorticoids (GC) administration on AM in developing lungs are still lacking.

OBJECTIVE

to investigate, in a sheep-based model, the positive/side-effects of combined exposure to CA and GC on AM concentrations measured in bronchoalveolar lavage fluid (BALF).

METHODS

Time-mated ewes were randomly admitted to one of six treatment groups receiving injection: saline (controls); lipopolysaccharide (L) in intra-amniotic fluid treated alone at 7 or 14 d before delivery or associated with betamethasone (B) intramuscularly; B treated alone (7d) or associated with L (14d). Lambs were surgically delivered at 120 days gestation and euthanized. BALF was used for AM measurement in the studied groups.

RESULTS

AM BALF levels significantly (p < 0.05, for all) changed both to B and L exposure in a time-dependent manner. The latter was characterized by AM levels at short term superimposable to controls, whilst significantly (p > 0.05) decreased at long-term. The former showed increased AM at short and decreased at long-term (p < 0.05, for all), respectively.

CONCLUSIONS

the present results showing AM BALF changes in a sheep-based model support the AM role in the hemodynamic patterns due to CA and BPD occurrence and open the way to further studies investigating the role of vasoactive agents as trustable markers of lung development/damage.

Adrenomedullin and pregnancy: perspectives from animal models to humans

A healthy pregnancy requires strict coordination of genetic, physiologic and environmental factors. The relatively common incidence of infertility and pregnancy complications has resulted in increased interest in understanding the mechanisms that underlie normal versus abnormal pregnancy. The peptide hormone adrenomedullin (AM) has recently been the focus of some exciting breakthroughs in the pregnancy field. Supported by mechanistic studies in genetic animal models, there continues to be a growing body of evidence demonstrating the importance of AM protein levels in a variety of human pregnancy complications. With more extensive mechanistic studies and improved consistency in clinical measurements of AM, there is great potential for the development of AM as a clinically-relevant biomarker in pregnancy and pregnancy complications.

Effect of corticosteroids and progesterone on adrenomedullin output and expression in human fetal membranes and placenta trophoblasts

OBJECTIVE

Plasma adrenomedullin (AM) concentrations are increased in fetal and maternal circulation in response to exogenous glucocorticoids administration. The role of corticosteroids and progesterone in regulating AM synthesis and secretion was investigated in amnion and chorion trophoblast cells of the fetal membranes and in placental trophoblast cells.

STUDY DESIGN

Cells were treated with betamethasone, hydrocortisone, and progesterone. Changes in AM output were measured with radioimmunoassay. Protein expression was evaluated with Western blot and immunohistochemistry.

RESULTS

Betamethasone stimulated AM secretion and protein expression in placental trophoblast cells and in amnion cells of the fetal membranes. Hydrocortisone and progesterone did not induce any effect either on secretion or protein expression in placenta and fetal membranes cells.

CONCLUSION

Glucocorticoids regulate AM secretion and expression by human placenta thereby promoting increased AM concentration in maternal and fetal circulation in circumstances characterized by increased cortisol levels.