Protein oxidative stress markers in peritoneal fluids of women with deep infiltrating endometriosis are increased.
OBJECTIVE
Are protein oxidative stress markers [thiols, advanced oxidation protein products (AOPP), protein carbonyls and nitrates/nitrites] in perioperative peritoneal fluid higher in women with histologically proven endometriosis when compared with endometriosis-free controls?


CONCLUSIONS
Protein oxidative stress markers are significantly increased in peritoneal fluids from women with deep infiltrating endometriosis with intestinal involvement when compared with endometriosis-free controls.


BACKGROUND
Endometriosis is a common gynaecologic condition characterized by an important inflammatory process. Various source of evidence support the role of oxidative stress in the development of endometriosis.


METHODS
We conducted a prospective laboratory study in a tertiary-care university hospital between January 2011 and December 2012, and included 235 non-pregnant women, younger than 42 year old, undergoing surgery for a benign gynaecological condition.


METHODS
After complete surgical exploration of the abdomino-pelvic cavity, 150 women with histologically proven endometriosis and 85 endometriosis-free controls women were enrolled. Women with endometriosis were staged according to a surgical classification in three different phenotypes of endometriosis: superficial peritoneal endometriosis (SUP), ovarian endometrioma (OMA) and deeply infiltrating endometriosis (DIE). Perioperative peritoneal fluids samples were obtained from all study participants. Thiols, AOPP, protein carbonyls and nitrates/nitrites were assayed in all peritoneal samples.


RESULTS
Concentrations of peritoneal AOPP were significantly higher in endometriosis patients than in the control group (median, 128.9 µmol/l; range, 0.3-1180.1 versus median, 77.8 µmol/l; range, 0.8-616.1; P < 0.001). In a similar manner concentrations of peritoneal nitrates/nitrites were higher in endometriosis patients than in the control group (median, 24.8 µmol/l; range, 1.6-681.6 versus median, 18.5 µmol/l; range, 1.6-184.5; P < 0.05). According to the surgical classification, peritoneal fluids protein AOPP and nitrates/nitrites were significantly increased only in DIE samples when compared with controls (P < 0.001 and P < 0.05; respectively), whereas the others forms of endometriosis (SUP and OMA) showed non-statistically significant increases. We found positive correlations between peritoneal fluids AOPP concentrations, nitrites/nitrates levels and the total number of intestinal DIE lesions (r = 0.464; P < 0.001 and r = 0.366; P = 0.007; respectively).


CONCLUSIONS
Inclusion of only surgical patients may constitute a possible selection bias. In fact, our control group involved women who underwent surgery for benign gynaecological conditions. This specificity of our control group may lead to biases stemming from the fact that some of these conditions, such as fibroids, ovarian cysts or tubal infertility, might be associated with altered peritoneal proteins oxidative stress markers.


CONCLUSIONS
We demonstrate the existence of a significantly increased protein oxidative stress status in peritoneal fluid from women with endometriosis especially in cases of DIE with intestinal involvement. This study opens the way to future more mechanistics studies to determine the exact role of protein oxidative stress in the pathogenesis of endometriosis. Even if an association does not establish proof of cause and effect, these intrinsic biochemical characteristics of endometriosis may lead to the evaluation of therapeutic approaches targeting oxidative imbalance.


BACKGROUND
No funding was used for this study. The authors have no conflict of interest.
Faculté de Médecine, AP-HP, Hôpital Cochin, Department of Gynecology Obstetrics II and Reproductive Medicine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, AP-HP, Hôpital Cochin, Laboratoire d'immunologie, Unité de recherche U1016, Equipe Batteux, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, Inserm, Unité de recherche U1016, Institut Cochin, CNRS (UMR 8104), Université Paris Descartes, Sorbonne Paris Cité, Paris, France pietro.santulli@cch.aphp.fr.
Pietro
P
Santulli
Faculté de Médecine, AP-HP, Hôpital Cochin, Laboratoire d'immunologie, Unité de recherche U1016, Equipe Batteux, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France.
Sandrine
S
Chouzenoux
Faculté de Médecine, AP-HP, Hôpital Cochin, Department of Gynecology Obstetrics II and Reproductive Medicine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France.
Mauro
M
Fiorese
Faculté de Médecine, AP-HP, Hôpital Cochin, Department of Gynecology Obstetrics II and Reproductive Medicine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, Inserm, Unité de recherche U1016, Institut Cochin, CNRS (UMR 8104), Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
Louis
L
Marcellin
Service de Diagnostic Biologique Automatisé, AP-HP, Hôpital Cochin, Paris 75679, France.
Herve
H
Lemarechal
Faculté de Médecine, AP-HP, Hôpital Cochin, Department of Gynecology Obstetrics II and Reproductive Medicine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France.
Anne-Elodie
AE
Millischer
Faculté de Médecine, AP-HP, Hôpital Cochin, Laboratoire d'immunologie, Unité de recherche U1016, Equipe Batteux, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France.
Frédéric
F
Batteux
Faculté de Médecine, AP-HP, Hôpital Cochin, Service de Diagnostic Biologique Automatisé, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, Inserm, Unité de recherché, UMR1124, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
Didier
D
Borderie
Faculté de Médecine, AP-HP, Hôpital Cochin, Department of Gynecology Obstetrics II and Reproductive Medicine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, AP-HP, Hôpital Cochin, Laboratoire d'immunologie, Unité de recherche U1016, Equipe Batteux, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris 75679, France Faculté de Médecine, Inserm, Unité de recherche U1016, Institut Cochin, CNRS (UMR 8104), Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
Charles
C
Chapron
D000328:Adult; D062107:Advanced Oxidation Protein Products / Q000378:metabolism; D001202:Ascitic Fluid / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D004715:Endometriosis / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D006801:Humans; D009566:Nitrates / Q000378:metabolism; D018384:Oxidative Stress; D011446:Prospective Studies; D050050:Protein Carbonylation; D013438:Sulfhydryl Compounds / Q000378:metabolism
D062107:Advanced Oxidation Protein Products; D015415:Biomarkers; D009566:Nitrates; D013438:Sulfhydryl Compounds
AOPP; endometriosis; nitrates/nitrites; oxidative stress; thiols