Endometriosis is characterized by the presence of endometrial stromal and glandular cells outside the uterine cavity, mainly in the pelvis [
Tenascin is a high molecular weight ECM protein and plays a critical role in tissue regeneration, hyperplastic, and neoplastic processes [
Tissue samples were collected in accordance with the requirements of the Firat University Hospital Ethical Committee between November 2008 and September 2009. Eutopic and ectopic endometrial samples were obtained from 45 women aged 18–40 years, body mass index ranged from 18.5 to 24.9 kg/m2 undergoing laparoscopy for benign indications, who had a regular 26–33 day menstrual cycle and who had received no hormonal medication in the preceding 3 months. Forty-five women classified into two groups; Group I: women who did not have pelvic pathology that was confirmed by ultrasonography and laparoscopy (
Peripheric venous 5 mL blood samples were collected after one-night fasting. After centrifugation of blood samples at 4000 rpm at room temperature for 10 minutes, 20–30
Paraffin-embedded tissue samples were cut into 5
Power calculation was performed based on previous studies that involved semiquantification of tenascin expression by immunohistochemistry. A sample size of 15 in each group has 80% power to detect a difference between means of 22.07 with a significance level (alpha) of .05. The statistical power analysis was performed using G power 3 programme. Statistical analysis was performed by Statistical Package for Social Sciences (SPSS) version 12.0 (Inc., Chicago, IL, USA). Results were expressed as mean and standard deviation. Differences in two groups for continous variables were analyzed using Student’s
The age, BMI, and waist/hip ratio of patients were as follows:
Serum and tissue levels of tenascin.
Group 1 |
Group 2 |
|
|
---|---|---|---|
Serum tenascin (ng/mL) | |||
(i) Proliferative phase | 41 ± 7 | 38 ± 8.5 | 0.73 |
(ii) Secretory phase | 39 ± 9 | 36 ± 9 | 0.95 |
Eutopic endometrial tenascin |
|||
(i) Proliferative phase | 30 ± 9 | 33 ± 14 | 0.93 |
(ii) Secretory phase | 319 ± 109 | 311 ± 127 | 0.71 |
Ectopic endometrial tenascin |
|||
(i) Proliferative phase | — | 32 ± 11 | — |
(ii) Secretory phase | — | 285 ± 100 | — |
Note: The results are presented as mean ± SD.
Serum and tissue levels of tenascin in women with and without endometriosis.
In immunohistochemical staining, intense staining of tenascin was observed in glandular cells of eutopic endometrial tissue samples of both groups during secretory phase (Figure
Immunostaining of tenascin in eutopic and ectopic endometria. In eutopic and ectopic endometrial glands tenascin was expressed diffusely in the secretory phase and downregulated in the proliferative phase. Stromal staining intensity of tenascin was very low in both of the eutopic and ectopic endometria (
The present study evaluated the serum and tissue levels of tenascin in eutopic and ectopic endometria. Immunohistochemical and immunoassay results pointed out increased tenascin expression during secretory phase in glandular cells of eutopic and ectopic endometrium. However, the changes in stromal cells were less dynamic than those in glandular cells of both eutopic and ectopic endometrium. Increased tissue levels of tenascin during secretory phase may indicate a paracrine function on endometrium and the influence of ovarian steroids on tenascin expression. The limitations of our study were the small study population and immunohistochemical analysis of tenascin, could be supported with the genetic analysis of tenascin expression.
Invasion, ectopic implantation, and recurrence are the pseudomalignant characteristics of endometriosis. New vessel formation, alteration of cellular immunity response, and apoptosis suppression are the integral mechanisms in the pathogenesis of endometriosis [
The function of endometrial tenascin is not well known but, it is thought that tenascin affects endometrial regeneration and endometriotic implantation via cellular adhesion [
Nishiura et al. reported that tenascin-C upregulated the expression of MMP-3 in mouse endometrial stromal cells during early pregnancy [
It is thought that epithelial-mesenchymal interactions with the influence of sex steroids play a critical role on endometriosis [
In conclusion, further studies are needed to investigate the possible effects of tenascin on formation of endometriotic lesions via their paracrine effects on ECM invasion.
The authors thank the doctors of Firat University Hospital, Department of Gynecology for their provided help during their study. This study was supported by Firat University Scientific Research Foundation.