Sister chromatid exchange (SCE) frequencies differ between directly prepared cytotrophoblasts and cultured mesenchymal core cells.

Analysis of sister chromatid exchange (SCE) in chorionic villus cells may become useful in measuring the response of fetal tissues to clastogens or mutagens or for prenatal diagnosis of chromosome breakage syndromes such as Bloom syndrome. Previous studies have failed to analyze cytotrophoblastic cells and mesenchymal core cells, or have found no difference between SCE frequencies in directly prepared and cultured cells. Our data indicate significant differences in SCE frequencies between the two cell types: SCE frequency in directly prepared cytotrophoblasts was 6.73 SCE/cell +/- 1.6, whereas SCE frequency in cultured mesenchymal core cells was 10.31 SCE/cell +/- 0.49 (P less than 0.001). SCE analyses involving chorionic villi must take into account cell type.