Human placental cytotrophoblast cells: identification and culture.

Methods of disaggregation of human placental tissue were assessed with the aim of maximising the yield of cytotrophoblast cells and minimising contamination with other cell types. Brief exposure to crude trypsin was found to be the best way to balance yield of trophoblast cells against contamination by cells of the villous core. Much higher yields of all cell types could be obtained by digestion with other enzymes. Staining for NADH diaphorase activity coupled with general morphology was found to be a reasonably specific, rapid and simple method of distinguishing cytotrophoblast cells in disaggregated mixtures. Alkaline phosphatase activity was an unreliable marker of trophoblast tissue in early placentas, and of the putative cytotrophoblast cells in mixtures of disaggregated cells. Cultures of cells obtained from term placentas were fairly homogeneous, whereas placentas of 6-12 weeks gestation gave heterogeneous cell cultures which became overgrown with fibroblasts.