EVIDENCE OF PRIMORDIAL GERM CELL IN HUMAN OVARIAN ENDOMETRIOTIC LESIONS

FRAUNHOFFER NICOLAS A.; MEILERMAN ABUELAFIA ANALIA.; STELLA INES; GALLIANO SILVIA; VITULLO ALFREDO D.

Yokohoma

Encuentro; International Society for Stem Cell Research 10th Annual Meeting; 2012

International Society for Stem Cell Research

Endometriosis is a common gynecological disorder affecting 10% of all women. This pathology is characterized by dysmenorrhea, dyspaneuria, pelvic pain, and infertility. In some cases, malignant transformation occurs in the lesion. Although this disorder was described in 1860, it still remains an enigmatic disease, mainly in its etiology. Sampson´s implantation theory is the most accepted explanation on the origin of endometriosis proposing that endometrial cells exfoliated during menstruation reflux through the uterine tubes, adhere to and proliferate at ectopic sites. Recently, the presence of stem cells in ovarian endometriosis was demonstrated; these cells could be involved in the progression of the disease and its malignant transformation. We propose that ovarian stem cells, lying in the gonad to renew the germinal mass, initially recruited to develop into primordial germ cells (PGC), act afterwards in the disease progression as a consequence of the hormonal environment of the endometriotic lesion. The main objective of this work was to search for the existence of PGC at ovarian endometrioma. Five samples were collected from patients, after obtaining their informed consent, according to the following criteria: histopathological diagnosis of ovarian endometriosis, women aged 18 to 35 years old, normal menstrual cycle and no history of any hormonal therapy. As control samples we used endometrial tissue both in proliferative and secretory phase (n=2 for each). Samples were processed by immunohistochemistry and immunofluorescence for: DDX4, IFITM-1, IFITM-3, OCT4, SSEA4, Progesterone receptor (PGR), Estrogen receptor alpha (ESR1), PCNA and CD45. Germ cell markers IFITM3 and DDX4 were strongly immunostained in clock face-arranged cells with central nucleolus. These cells also displayed nuclear signal for ESR1, PCNA and SSEA4 but were negative for PGR, OCT4 and CD45. Positive cells for PGR, ERS1, OCT4 and PCNA were found in the stroma of all the endometriotic lesions and endometrial control samples. The expression of PGR, DDX4, IFITM1 and IFITM3 was analyzed by RT-PCR from formalin-fixed paraffin embedded tissue. DDX4, IFITM1, and IFITM3 mRNAs were expressed in all endometriotic samples but not in endometrial tissues. The presence of DDX4, IFITM1 and IFITM3 indicates the existence of PGC in ovarian endometriotic lesions. Additionally, the expression of ESR1 suggests that these cells were probably recruited due to estrogenic stimulation from ovarian stem cells, with loss of OCT4 activity while maintaining the expression of SSEA4. These results outline ovarian endometriosis as a model for studying the renewal of the germinal mass in the female gonad.