Cell cycle analysis and detection of proliferative cell nuclear antigen of the endometrium after hormone replacement therapy

Differential expression of NUDT9 at different phases of the menstrual cycle and in different components of normal and neoplastic human endometrium

OBJECTIVE

The human endometrium manifests different and distinct morphologies and physiologies during the different phases of the menstrual cycle. We aimed to determine which candidate genes demonstrate differential expression patterns in the endometrium during different phases of the menstrual cycle.

MATERIALS AND METHODS

Using differential display reverse transcription polymerase chain reaction to compare day 5 and day 18 human glandular endometrium obtained by laser capture microdissection, we identified a specific gene, NUDT9 (nucleoside diphosphate-linked moiety X motif 9). NUDT9 is known to function as a highly specific adenosine diphosphate ribose pyrophosphatase and has been mapped to chromosome 4q22.1. It gives rise to two alternatively spliced messenger RNAs, NUDT9alpha and NUDT9beta, encoding a member of the Nudix hydrolase family. In this study, we purified NUDT9 protein and produced an antibody, which we then used for immunohistochemical studies.

RESULTS

Using this anti-NUDT9 antibody, we successfully demonstrated that NUDT9 protein was differentially expressed in endometrial glandular cells at different phases of the menstrual cycle. NUDT9 was also found to be expressed more prominently in the epithelial glandular component than in the stromal component of human endometrial carcinomas.

CONCLUSION

We suggest that NUDT9 may be involved in the regulation of the menstrual cycle and may be related to the proliferation of glandular cells in the human endometrium.

Comparison of the difference in histopathology and cell cycle kinetics among the postmenopausal endometrium treated with different progestins in sequential-combined hormone replacement therapy

OBJECTIVE

To investigate the difference in histopathology and cell cycle kinetics in the menopausal endometrium treated with sequential-combined hormone replacement therapy (HRT) using different types and doses of progestins.

DESIGN

A randomized, double-blind, 1-year study was conducted. In a menopause clinic of a university hospital, 241 postmenopausal women using HRT were included for the study of histopathology and cell cycle analysis. Conjugated equine estrogens, 0.625mg/day, were administered for 25 days (days 1-25) of each month, and the following were also administered for 14 days (days 12-25): in group A ( n= 102), medroxyprogesterone acetate (MPA), 5 mg/day; in group B ( n= 66), MPA, 10mg/day; and in group C ( n= 73), dydrogesterone, 20mg/day. Endometrial sampling was performed after at least 10 months of treatment. Fifty-two premenopausal women were also enrolled for the comparative studies (group Y). The S-G2-M fractions in the cell cycle were used as the marker of proliferation.

RESULTS

Most menopausal endometria were normal regardless of the regimens of HRT. Endometrial hyperplasia was only found in two cases (both in group A). The S-G2-M fractions of the endometrial cells in all three menopausal groups showed no statistically significant difference. It appeared that S-G2-M fractions increased from normal postmenopausal to normal premenopausal endometria to postmenopausal hyperplasia to premenopausal hyperplasia. The S-G2-M fractions of the normal menopausal endometrial cells were lower than those of the premenopausal controls either in normal or in hyperplastic categories.

CONCLUSIONS

Our study showed that there is no difference between the effect of MPA and dydrogesterone used in sequential-combined HRT based on the cycle kinetics of the menopausal endometrium.