PLACENTAL G-CSF CAN MODULATE IN VITRO THE SYNTHESIS OF FLT-1 BY PERITONEAL MACROPHAGES

LITWIN S, PRADOS MB, MRANDA S.

Buenos Aires, Argentina

Jornada; VIII Jornadas Multidiciplinarias de la Sociedad Argentina de Biología; 2006

Sociedad Argentina de Biología

We have previously reported that multiparity status induces an increase of G-CSF expression in spongiotrophoblast, in the nuber of placental macrophages next to decidua and in the layers of invasive trophoblast tissue (ITT). Moreover, ITT cells showed an important expression of G-CSF, M.CSF, VEGF and its receptor Flt-1. Taing into account that M-CSF and G-CSF have proved to modulate macrophage activity, here we investigated whether placental culture supernatants (PS) were able to influence the secretion of VEGF ans sFlt-1 by isolated peritoneal macrophages. M&M: term placenta were obtained from normal CBA/J x BALB/c and abortion prone CBA/J x DBA/a crossbreedings, which were previously divided into 3 groups: primiparous young (PY: 3 months old), primiparous old (PO: 8.5 months old) and multiparous old (MO: 8.5 months old and 4 pregnancies). Placenta were minced and cultured (76 ± 4 mg/ml). The respected PS were incubated or not with anti-G-CSF. Non inflammatory peritoneal macrophages were obtained from BALB/c mice, cultured (3x106 /ml) alone (CM) or in the presence of 10% of the different neutralized (ReN) and not neutralized (Re) PS. Controls of PS were also carried out. VEGF ans sFlt-1 were investigated in all the obtained culture supernatants by ELISA. The presence of G-CSF and M-CSF in the PS was checked by western blot. Results: VEGF conc. (pg/ml): CM: 35±15; CPS 80±20; Re and both ReN: not detected (nd). sFtl-1 conc (ng/ml): CM: nd; CPS: between 36 and 47, Re: 140±30, ReN with anti-G-CSF: diminishing of aprox. 50%. Our results would indicate that G-CSF secreted by placenta induce the in vitro synthesis of sFtl-1 by peritoneal macrophages sequestrating the VEGF produced. We suggest that this mechanism may partially explain the increase of Flt-1 observed in multiparous placenta.