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Published on: May 23, 2014
Proliferative activity of lymphoid cells in human endometrium throughout the menstrual cycle
1Department of Pathology, City Hospital Center, Elmhurst, New York 11373.
Insights
Human endometrial lymphoid cells proliferate throughout the menstrual cycle. Their proliferative activity significantly increases during the secretory phase, suggesting in situ proliferation restores the immune cell pool after shedding.
Area of Science:
- Immunology
- Reproductive Biology
- Cell Biology
Background:
- The human endometrium contains a substantial population of lymphoid cells.
- Understanding the dynamics of these immune cells is crucial for reproductive health.
Purpose of the Study:
- To investigate the proliferation of endometrial lymphoid cells throughout the menstrual cycle.
- To determine the role of in situ proliferation in maintaining the endometrial immune cell population.
Main Methods:
- In situ labeling of endometrial sections for Ki67 (proliferation marker).
- In vitro bromodeoxyuridine (BrdU) incorporation assay for S-phase cells.
- Immunostaining for lymphoid cell markers (CD45, CD3) and macrophage marker (CD11c).
Main Results:
- Lymphoid cells, including CD45+, CD3+, and CD11c+ cells, show Ki67 positivity throughout the cycle.
- Proliferative activity markedly increases in the secretory phase for stromal lymphoid cells.
- BrdU labeling confirms increased lymphoid cell proliferation during the secretory phase.
Conclusions:
- In situ proliferation is a key mechanism for restoring the endometrial lymphoid cell pool.
- Endometrial immune cell dynamics are significantly influenced by the menstrual cycle phase.
Abstract:
Human endometrium harbors a major population of lymphoid cells. The proliferation of these cells is assessed by the in situ labeling of endometrial sections for Ki67 (a proliferation marker) as well as in vitro incorporation of bromodeoxyuridine (BrdU; a thymidine analog) into S-phase cells in vibratome sections of endometria. Using the avidin-biotinperoxidase complex method, sections of endometria and vibratome sections of endometria are labeled for Ki67 and BrdU, respectively. Subsequently, they are immunostained for CD45 (a lymphoid cell marker), CD3 (a T cell marker), and CD11c (a macrophage marker) molecules. Lymphoid cells scattered or aggregated in the endometrial stroma as well as intraglandular lymphoid cells exhibit Ki67 positivity throughout the menstrual cycle. The proliferative activity of the lymphoid cells, including the CD45, CD3, and CD11c positive cells scattered in the stroma, is markedly increased in the secretory phase. Similar, however less conspicuous, increased Ki67 labeling is observed in the lymphoid cells within lymphoid aggregates. The increased proliferative activity of the lymphoid cells in the secretory phase is confirmed by BrdU labeling in the vibratome sections. In the proliferative phase the non-CD45-positive cells in the endometrial stroma exhibit low proliferative activity, and in the secretory phase, Ki67 labeling in the endometrial stroma is primarily confined to the CD45-positive cells. The findings suggest that in situ proliferation is one mechanism by which the endometrial lymphoid cell pool within endometrium is restored after each menstrual shedding.
