Invasion process of induced deep nodular endometriosis in an experimental baboon model: similarities with collective cell migration?

Objective: To determine the implications of collective cell migration in the invasion phenomenon observed in deep endometriotic lesions induced in a baboon model.

Design: Study of morphology and collective cell migration markers in invasive and noninvasive deep endometriotic lesions induced in a baboon model. Invasive lesions were defined as the presence of endometrial glands and stroma in surrounding organs, and a distinction was made between the center of the lesion (glands present in the main lesion) and the invasion front (glands present in surrounding organs).

Setting: Academic research unit.

Animal(s): Ten female baboons (Papio anubis).

Intervention(s): Recovery of induced deep nodular endometriotic nodules.

Main Outcome Measure(s): Evaluation of the morphology of glands by analysis of noninvasive and invasive lesions (center of the lesion and invasion front); staining with specific antibodies (Ki67, E-cadherin, β-catenin) for immunohistochemical study of mitotic activity and cell-cell junctions.

Result(s): Glands from invasive lesions, particularly from the invasion front, showed a significantly lower thickness coefficient, higher mitotic activity, and lower expression of E-cadherin and β-catenin than glands from noninvasive lesions and the center of invasive lesions.

Conclusion(s): We report altered morphology, increased mitotic activity, and fewer adhesion molecules in invasive glands present in induced nodular endometriosis, particularly along the invasion front, suggesting that collective cell migration is involved in the invasion process of deep endometriotic lesions induced in a baboon model.