Apoptosis in Endometrial Glandular and Stromal Cells in 
Women with and Without Endometriosis

Presentation Title: “Apoptosis in Endometrial Glandular and Stromal Cells in Women with and Without Endometriosis”
Authors: 1J. Ding, 1,2J. Shen, 1,2D. Braun, 1,2N. 1,2Rana, 3B. Fernandez & 1,2W. Dmowski
Affiliation: 1Institute for the Study and Treatment of Endometriosis, Chicago, IL, 2Rush Medical College, Chicago, IL, 3Department of Pathology, Elmhurst Hospital, Elmhurst, IL.

Summary written by Christine Schroeder, Ph.D.

The researchers in this study hypothesized that spontaneous apoptosis, or programmed cell death may play an important role in endometriosis. The reasoning behind this theory is that, during the menstrual cycle, cells in the endometrium will die off and conclude that phase of the endometrium. If these cells do not die off, then in essence, the uterus is still full of active endometrial cells; should these cells find their way outside the uterus, they may then implant and cause endometriosis. In contrast, a cell that had undergone programmed cell death would not cause the same problems; even if it found its way outside the uterus, it would not be capable of implanting and continuing its existence.

It was thus hypothesized that women with endometriosis would have lower levels of programmed cell death (apoptosis) than women without endometriosis. Results of a previous study provided evidence in support of this hypothesis; the purpose of the current study was to further confirm the previous findings and also examine apoptosis throughout the monthly cycle. For the purposes of this study, the monthly cycle was divided into three phases:

• Menstrual
• Proliferative
• Secretory

Participants in the study were 61 women who had undergone laparascopic diagnosis for endometriosis. Endometrial samples were also available for these patients. For the purposes of the study, three factors were taken into account:

Whether the laparoscopy had shown endometriosis 
The phase of the menstrual cycle of the endometrium sample 
The concentration of apoptotic cells per 10mm2 area of endometrium sample 
Researchers also looked at the early, middle, and late parts of the proliferative and secretory phases. Forty-eight of the 61 women were diagnosed laparoscopically with endometriosis (the ENDO group), the remainder received a negative diagnosis (the NO ENDO group).

The results revealed the following:

Overall (that is, for all phases of the menstrual cycle), the ENDO group had a significantly lower concentration of apoptotic cells than the NO ENDO group. The mean for the ENDO group was 55.1 cells per 10 mm2 of endometrial tissue, whereas the mean for the NO ENDO group was 121.7 cells per 10 mm2 of tissue. 
The endometrium was also subdivided into stromal and grandular sections. This analysis found the same results in both types of sections – the ENDO group had fewer apoptotic cells than the NO ENDO group. 
A comparison of the tissues from the various phases of the menstrual cycle indicated that, among the NO ENDO patients, cellular apoptosis was highest in the early proleferative and late secretory phases, which would be right before and after menses. 
In contrast, patients in the ENDO group had similar levels of apoptosis throughout the menstrual cycle.

Note: Although these results may not be of immediate use to the average infertility patient, I think the implications of this study are absolutely fascinating. They suggest that endometriosis patients may retain active endometrial cells at times that they should not, and that these cells may then migrate to atypical locations and “cause trouble”. It is particularly interesting that endometriosis patients not only have a lower level of cellular apoptosis, but that this apoptosis also does not fluctuate around the time of menses like it does in women without endometriosis.