Proliferation kinetics of chorionic villi in chromosomally normal and abnormal spontaneous abortions analyzed by premature chromosome condensation and northern blot.

The activity of cell proliferation in human chorionic villi (CV) obtained from early spontaneous abortions (SAB) and from elective abortions (EAB) was determined by means of premature chromosome condensation (PCC), and by Northern blot analysis of expression of proliferation antigens Ki67 and PCNA. The rate of chromosome aberrations among the SABs was 57%, while the EABs, taken as controls, were shown to be chromosomally normal. PCCs were induced by fusion of the chorionic interphase cells with mitotic Chinese hamster ovary (CHO) cells. To analyze the proliferation stages of the chorionic G1-interphases, the potential proliferation index (PPI) was ascertained. The PPI values found in SABs ranged from 36% to 97% as described for intensely proliferating tissues. They did not differ from the values found in the controls (34-90%), indicating maintenance of proliferation activity of CV cells even after death of the embryo in missed abortions. No significant PPI differences were observed between the abortion groups with different cytogenetic results. The expression of proliferation associated antigens Ki67 and PCNA showed no significant differences between mean values of the total of SABs and of the controls. However, the comparison of mean values of chromosomally abnormal with chromosomally normal SABs revealed a significantly reduced Ki67 activity in the SABs with chromosome aberrations. A similar results was obtained when comparing mean values of Ki67 and PCNA expression from trisomic SABs with those of the controls. By further subdivision of chromosome aberrations a decrease for the expression of both antigens in chorionic villi from early lethal trisomies, and a significantly increased Ki67- and PCNA-expression in triploidies became evident.