STUDY QUESTION
Can prostaglandin E2 (PGE2) in menstrual and peritoneal fluid (PF) promote bacterial growth in women with endometriosis?
SUMMARY ANSWER
PGE2 promotes bacterial growth in women with endometriosis.
WHAT IS KNOWN ALREADY
Menstrual blood of women with endometriosis is highly contaminated with Escherichia coli (E. coli) compared with that of non-endometriotic women: E. coli-derived lipopolysaccharide (LPS) promotes the growth of endometriosis.
STUDY DESIGN, SIZE AND DURATION
Case-controlled biological research with a prospective collection of body fluids and endometrial tissues from women with and without endometriosis with retrospective evaluation.
PARTICIPANTS/MATERIALS, SETTING AND METHODS
PF and sera were collected from 58 women with endometriosis and 28 women without endometriosis in an academic research laboratory. Menstrual blood was collected from a proportion of these women. Macrophages (M) from PF and stromal cells from eutopic endometria were isolated in primary culture. The exogenous effect of PGE2 on the replication of E. coli was examined in a bacterial culture system. Levels of PGE2 in different body fluids and in the culture media of M and stromal cells were measured by ELISA. The effect of PGE2 on the growth of peripheral blood lymphocytes (PBLs) was examined.
MAIN RESULTS AND THE ROLE OF CHANCE
The PGE2 level was 2–3 times higher in the menstrual fluid (MF) than in either sera or in PF. A significantly higher level of PGE2 was found in the MF and PF of women with endometriosis than in control women (P < 0.05 for each). Exogenous treatment with PGE2 dose dependently increased E. coli colony formation when compared with non-treated bacteria. PGE2-enriched MF was able to stimulate the growth of E. coli in a dilution-dependent manner; this effect was more significantly enhanced in women with endometriosis than in control women (P < 0.05). PGE2 levels in the culture media of LPS-treated M/stromal cells were significantly higher in women with endometriosis than in non-endometriosis (P < 0.05 for each). Direct application of PGE2 and culture media derived from endometrial M or stromal cells significantly suppressed phytohemagglutinin-stimulated growth of PBLs.
LIMITATIONS AND REASONS FOR CAUTION
Further studies are needed to examine the association between PGE2-stimulated growth of E. coli and endotoxin level and to investigate the possible occurrence of sub-clinical infection within vaginal cavity.
WIDER IMPLICATIONS OF THE FINDINGS
Our findings may provide some new insights to understand the physiopathology or pathogenesis of the mysterious disease endometriosis and may hold new therapeutic potential.
STUDY FUNDING/COMPETING INTEREST(S)
This work was supported by grants-in-aid for Scientific Research from the Ministry of Education, Sports, Culture, Science and Technology of Japan. There is no conflict of interest related to this study.
TRIAL REGISTRATION NUMBER
Not applicable.
Source:
http://humrep.oxfordjournals.org/cgi/content/short/27/12/3417?rss=1
Recommendation and review posted by G. Smith
