Resumen

CASTEJON S, Olivar C; SCUCCES M, Maria G; RIVAS A, Alba E  y  MOLINA VILCHEZ, Rafael. Vasculogénesis en la vellosidad placentaria humana de nueve semanas. Gac Méd Caracas [online]. 2002, vol.110, n.4, pp.504-511. ISSN 0367-4762.

Disturbances in the placental vascular development demonstrated by reduced fetal capillary branching and alterations in the expression of angiogenic factors have been associated with aborts, preeclampsia intra uterine growth retardation and diabetes. This negative influence on fetal development has raised urgent demand for a better knowledge of the formation of intravellous vessel by stains of hematoxiline-eosine. Especimens were taken from an therapic abort of nine weeks of gestation with exact clinic and ultrasonographic date. The findings reveal immature intermediate villi, stem villi and numerous macrophages. Vasculogenesis from transformation mesenchymal cells to haemangiogenetic cell that produce endothelial cells of primitive capillar tubes was observed. Clear spaces between two or three of these later cells indicated the lumen of the vessel. Four types of cells could be observed: mesenchyrnal, Hofbauer cells, haemangiogenetic and presumptive pericytes. Stem villi demonstrated vessels, with nucleated erythrocytes, and vessels walls appeared formed by smooth muscle fibers. Short capillar tubes were observed lumenized with nucleated erythrocytes near to trophoblast. Sometimes these were seen isolated in the stroma. In some cases stromal reticular cells take the feature of "C" cells. In conclusion, three mechanisrns as vasculogenesis, angiogenesis and replication of endothelial cells are presumptive of being active in this week (9).

Palabras clave : Vasculogenesis; Angiogenesis; human placental villi.