Background: The pathogenesis of endometriosis remains poorly defined. The aberrant angiogenesis that occurs in eutopic endometrium may play a role in the lesion formation and survival. The difference in gene expression profile between human endometrial endothelial cells (HEECs) from eutopic endometria of patients with and without endometriosis would be a factor that affects the occurrence of endometriosis.
Methods: To explore the difference, we performed in vitro culture and identified the endothelial origin, as well as observed growth features, of HEECs from the two different sources. We also identified their differences in gene expression profiles by combined suppression subtractive hybridization (SSH) with Genechip, and confirmed the results by quantitative reverse transcription-polymerase chain reaction.
Results: The HEECs derived from endometriosis patients exhibited a potent survival ability in vitro compared with those from non-endometriosis patients. In the HEECs from EM patients, an altered secretion pattern of extracellular matrix (ECM) components and up-regulation of GREM1 were found. These findings may be used to interpret the remarkable change of phenotype in HEECs from endometriosis patients. The synergistic action of these differentially expressed genes is to promote cell proliferation and concomitantly to inhibit apoptosis. Among the up-regulated ECM genes, TSP2 was the only one which exhibits the capacity to suppress angiogenesis; it may therefore function as an antagonist to the aberrant angiogenesis and may confine its extent and severity.
Conclusion: It may be postulated that differential regulation of some of these genes in eutopic HEECs plays a facilitating role during the peritoneal vascularization of ectopic endometrial lesions by enhancing angiogenic activity via a paracrine effect.