Laminin in the human embryo implantation: analogy to the invasion by malignant cells.

OBJECTIVE

To explore the possible similarities between the biochemical processes of embryo implantation and malignant invasion.

DESIGN

The expression of a basement membrane (BM) glycoprotein laminin, a matrix binding cell surface receptor protein beta 1-integrin, and a BM collagen degrading metalloproteinase type IV collagenase, was studied in cultured human in vitro fertilized embryos.

PATIENTS

Eight healthy women suffering from tubal infertility were participating in the IVF program in the Department of Obstetrics and Gynecology in University Hospital of Oulu. Twenty oocytes and 110 pre-embryos that were not transferred for the fertilizations were used in this study.

MAIN OUTCOME MEASURES

Fibronectin, laminin, beta 1-integrin, and type IV collagenase immunoreactive proteins were studied in embryos by immunoperoxidase staining, and type IV collagen degrading activity was measured from the culture media of the embryos.

RESULTS

Laminin and beta 1-integrin were expressed in the early human embryos before the time of implantation. Type IV collagen degrading activity and the 72 kd-type IV collagenase immunoreactive protein were expressed at the time of implantation. Laminin supported the expression of type IV collagenase.

CONCLUSIONS

The expression of laminin, beta 1-integrin, and type IV collagenase in vitro are temporally in good correlation with the time of the implantation in vivo. Laminin and beta 1-integrin can relate to the attachment of the embryos to the uterine BM and type IV collagenase to the degradation of the BM collagen during the implantation. Laminin can augment the process locally.