¡°Placental G-CSF can Modulate the in vitro Synthesis of Flt-1 by Peritoneal Macrophages¡±

S. LITWIN, M. B. PRADOS AND S. MIRANDA.

Buenos Aires

Jornada; VIII Jornadas Multidisciplinarias de la Sociedad Argentina de Biología.; 2006

Sociedad argentina de biología

Placental G-CSF can Modulate the in vitro Synthesis of Flt-1 by Peritoneal Macrophages S. Litwin, M. B. Prados and S. Miranda. IDEHU (CONICET-UBA). We have previously reported that multiparity status induces an increase in the expression of G-CSF in spongiotrophoblast, in the number 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. Taking into account that M-CSF and G-CSF have proved to modulate macrophage activity, here we investigated whether placental culture supernantants (PS) were able to influence the secretion of VEGF and sFlt-1 by isolated peritoneal macrophages. Term placentae were obtained from normal CBA/J x BALB/c and abortion-prone CBA/J x DBA/2 crossbreedings, which were previously divided into 3 groups, according to their age and parity status: primiparous young (PY: 3 months old), primiparous old (PO: 8.5 months old) and multiparous old (MO: 8.5 months old and four pregnancies). Placentae were minced and cultured for 48 hs (76 ¡¾ 4 mg/ml). The respective PS were incubated at 37¢ªC 1h or not with anti G-CSF and anti-M-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 (CPS). VEGF and 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¡¾15; CPS: 80¡¾20; Re and both ReN: not detected (nd). sFlt-1 conc. (ng/ml): CM: nd; CPS: 36 to 47 (depending on the groups); Re and ReN with anti M-CSF: 140¡¾30; ReN with anti G-CSF: diminishing between 30 to 60% depending on the analyzed groups. Our results would indicate that G-CSF secreted by placentae induce the in vitro synthesis of sFlt-1 by peritoneal macrophages sequestering all the VEGF produced. We suggest that this mechanism may explain the differences observed in multiparous placentae.