Correlation between inflammatory biomarkers in biological fluids in patients with ovarian endometriosis

BACKGROUND: To date, there are no available screening techniques allowing to distinguish groups of women with the risk of endometriosis. Therefore, many researchers are searching for meaningful biomarkers for non-invasive diagnosis. The peritoneal fluid is subject to multidirectional changes in patients with external genital endometriosis, although its sampling requires invasive procedure. Testing of the inflammatory markers in saliva is a simple and safe method of particular interest, given that its sampling is non-invasive. AIM: To assess the correlations between the level of inflammatory biomarkers in the peritoneal fluid and saliva in patients with ovarian endometriosis. MATERIAL AND METHODS: A prospective cohort comparative study of 46 women with ovarian endometriosis was carried out. Inclusion criteria: confirmed diagnosis of ovarian endometriosis; age between 18 and 40 years; written informed consent for surgical intervention and for participation in the study; no prior hormonal treatment. Non-inclusion criteria: patient's refusal to participate in the study; age below 18 and above 40 years; contraindications for surgical treatment; oral inflammatory diseases. Patients were excluded if the diagnosis could not be visually confirmed during surgery or if there were histological discrepancies. All patients underwent laparoscopic cystectomy. Peritoneal fluid samples were collected during surgery. Mixed unstimulated saliva was collected before surgery in the morning, on an empty stomach. The levels of interleukins and of vascular endothelial growth factor were assessed in biological fluids. RESULTS: The mean age of the study subjects was 32,4±6,1 years. Correlation analysis showed a direct statistically significant moderate relationship between the levels of IL-6 (r=0.548; p=0.001) and IL-8 (r=0.360; p=0.026) in the peritoneal fluid and saliva, respectively. CONCLUSION: These data suggest that the onset and progression of endometriosis are associated with the increase of inflammatory cytokine levels both in the peritoneal fluid and in saliva. This may serve a potential tool for diagnosis and assessment of the severity of endometriosis. Evaluation of IL-6 and IL-8 levels in saliva may be useful in clinical practice in patients with external genital endometriosis.