Increased expression of macrophage colony-stimulating factor and its receptor in patients with endometriosis

Abstract

Objective: To investigate the expression and regulation of colony-stimulating factor 1 (CSF-1) and its receptor, C-FMS, in endometriosis.

Design: In vivo and vitro study.

Setting: University-based academic medical center.

Patient(s): Reproductive-age women undergoing surgery for benign conditions.

Intervention(s): Peritoneal and endometrial tissue samples were obtained.

Main outcome measure(s): CSF-1 and C-FMS expression.

Result(s): Significantly higher CSF-1 levels were found in peritoneal fluid of patients with endometriosis compared with control subjects. Ectopic endometriotic tissue had 3.5-fold and 1.7-fold increases in CSF-1 and C-FMS expression, respectively, compared with eutopic tissue. Coculture of endometrial cells from either established cell lines or patient samples with peritoneal mesothelial cells (PMCs) led to increased expression of CSF-1 and C-FMS. A higher but nonsignificant increase in levels of C-FMS and CSF-1 was found in cocultures of endometrial epithelial cells from patients with endometriosis compared with those without endometriosis.

Conclusion(s): Increased CSF-1 levels may contribute to endometriosis lesion formation and progression. Elevation in CSF-1 after coculture of endometrial cells with PMCs suggests that endometrial tissue may be a source of peritoneal CSF-1. Increased C-FMS expression in endometrial cells from women with endometriosis cocultured with PMCs suggests that endometrial tissue involved in lesion formation is highly responsive to CSF-1 signaling.

Figure 1

Purity of endometrial stromal (ESCs) and epithelial (EECs) cells. ESCs and EECs were separated with 98.3% and 98.6% purity by flow cytometry with EECs stained for cytokeratin-18 and ESCs stained for vimentin.

Figure 2

Peritoneal fluid concentration (ng/mL) of colony-stimulating factor 1 (CSF-1) in patients with endometriosis compared with patients without endometriosis (control). Peritoneal fluid concentration of CSF-1 is higher in patients with endometriosis. Values are expressed as mean ± SD. *P ≤.002.

Figure 3

Colony-stimulating factor 1 (CSF-1) and its receptor, C-FMS, expression in ectopic tissue compared with paired eutopic tissue from women with endometriosis. Representative Western blot analysis (top) shows increased CSF-1 and C-FMS levels in ectopic lesions compared with paired eutopic endometrium. A relative increase in CSF-1 (∼3-fold increase) and C-FMS (∼1.7-fold increase) expression was seen in ectopic endometrial tissue compared with eutopic endometrial tissue samples. *P<.01; **P<.05.

Figure 4

(A) Colony-stimulating factor 1 (CSF-1) and its receptor, C-FMS, expression in EECs from women with endometriosis compared with women without endometriosis (control) after coculture with peritoneal mesothelial cells (PMCs). Reverse-transcription polymerase chain reaction (RT-PCR) analysis was used to determine RNA expression of CSF-1 and C-FMS. Endometrial epithelial cells (EECs) that were not exposed to PMCs were used as baseline control. Individual data points are represented by dashes with the mean for each group indicated by an X. (B) CSF-1 and C-FMS expression in endometrial stroma cells (ESCs) from women with endometriosis compared to women without endometriosis (control) after coculture with PMCs. RT-PCR analysis was used to determine RNA expression of CSF-1 and C-FMS. ESCs that were not exposed to PMCs were used as baseline control. Individual data points are represented by dashes with the mean for each group indicated by an X.