Increased expression of matrix metalloproteinase-9 in the eutopic endometrial tissue of women with endometriosis.
BACKGROUND
Endometriosis is a disease where endometrial tissue implants in ectopic locations. Remodelling of the extracellular matrix (ECM) is a prerequisite for the implantation of this tissue to be possible.


METHODS
In this study, we detected immunoreactive matrix metalloproteinase-9 (MMP-9) throughout endometrial tissue and identified von Willebrand factor (vWF)-positive endothelial cells, CD45-positive leukocytes, CD3-positive T lymphocytes and CD68-positive macrophages as cells expressing MMP-9 in the stroma.


RESULTS
We found an increased expression of MMP-9 in the uterine endometrial tissue of women with endometriosis, as assessed by zymography and enzyme-linked immunosorbent assay (ELISA) (P < 0.05). However, RT-PCR did not show a statistically significant increase in MMP-9 mRNA expression in these tissues (P = 0.14). There was no significant difference between women with and without endometriosis in the expression of tissue inhibitor of MMPs (TIMP)-1, a known natural inhibitor of the pro- and active forms of MMP-9, whether tested by ELISA or by RT-PCR (P = 0.46 and 0.37, respectively). Interestingly, the ratio of MMP-9/TIMP-1 expression was significantly higher in women with endometriosis than in normal women both at the protein and the mRNA levels (P < 0.05).


CONCLUSIONS
These findings make plausible the involvement of MMP-9/TIMP-1 imbalance in the invasiveness of the endometrial tissue of patients with endometriosis and the ectopic development of the disease.
Collette
T
T
Centre de Recherche, Hôpital Saint-François d'Assise, Centre Hospitalier Universitaire de Québec, Canada.
Maheux
R
R
Mailloux
J
J
Akoum
A
A
D000328:Adult; D016022:Case-Control Studies; D004715:Endometriosis / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D006801:Humans; D010535:Laparoscopy; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008597:Menstrual Cycle; D012333:RNA, Messenger / Q000378:metabolism*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*
D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9