Synchronous expression of pinopodes and alpha v beta 3 and alpha 4 beta 1 integrins in the endometrial surface epithelium of normally menstruating women during the implantation window.

OBJECTIVE

To use histology, scanning electron microscopy (SEM) and immunohistochemistry to examine the expression of pinopodes, and alpha v beta 3 and alpha 4 beta 1 integrins in the same endometrial biopsies.

STUDY DESIGN

A prospective observational study. Fifteen consecutive regularly menstruating women with normal hormone profiles were followed for detection of ovulation and then biopsied twice, on postovulatory days luteinizing hormone (LH) +6 and LH +8. Measurements included abundance and development stage of pinopodes and a semiquantitative assessment of intensity of antibody staining for integrins.

RESULTS

All biopsies observed under light microscopy showed an in-phase endometrium. Pinopodes were found developing mostly on day LH +6 and were fully developed on day LH +8. The expression of alpha v beta 3 dimer increased significantly from day LH +6 to day LH +8, while alpha 4 beta 1 dimer did not show any significant change during the same period. Fully developed pinopodes and strong intensity of alpha v beta 3 integrin were the most common findings.

CONCLUSION

These results indicate a coordinated, synchronous change in morphology and adhesion molecule expression of endometrial epithelial cells on day LH +8 of a normal menstrual cycle.