Menstrual activity of matrix metalloproteinases is decreased in endometrium regenerating after thermal ablation.
BACKGROUND
Menstruation is associated with a striking increase in matrix metalloproteinase (MMP) activity. However, it is still unknown whether the level of MMP activity correlates with the amount of menstrual bleeding.


METHODS
We used histochemistry to investigate the degradation of the extracellular matrix (ECM), and immunohistochemical labelling and zymographic analysis to determine the level of expression and activity of MMP-2 and -9, and of their tissue inhibitors (TIMPs) -1, -2 and -3, in endometria sampled during menstruation in 14 women experiencing excessive menstrual bleeding and in 10 women successfully treated for menorrhagia by thermal ablation of the endometrium.


RESULTS
After thermal ablation, regenerated menstrual endometria showed reduced areas of collagen fibre lysis and increased content of TIMP-1 and TIMP-2 compared with endometria from non-treated menorrhagic women. Surprisingly, treated endometria contained more latent gelatinase A (proMMP-2) but a lower proportion of the active form of gelatinase B (MMP-9) than non-treated endometria.


CONCLUSIONS
These results suggest that ECM degradation is decreased at menstruation in the endometrium regenerated after thermal ablation, mostly because of an increased TIMP expression. This represents the first molecular explanation for the decreased amount of menstrual bleeding.
Brun
J L
JL
Department of Gynaecology and Obstetrics, Hôpital Universitaire Pellegrin, Place Amélie-Raba-Léon, F-33076 Bordeaux, France. jean-luc.brun@chu-bordeaux.fr
Galant
C
C
Delvaux
D
D
Lemoine
P
P
Henriet
P
P
Courtoy
P J
PJ
Marbaix
E
E
D000328:Adult; D055356:Endometrial Ablation Techniques; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008595:Menorrhagia / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D016896:Treatment Outcome
D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9