Abstract
BackgroundVarious endometrial abnormalities have been associated with luteal phase deficiency: a significant dyssynchrony in the maturation of the glandular epithelium and the stroma and a prevalence of out-of-phase endometrial biopsy specimens. Out-of phase endometrium is a controversial disorder related to failed implantation, infertility and early pregnancy loss. Given that the regulation of the apoptotic process in endometrium of luteal phase deficiency is still unknown, the aim of this study was to evaluate cell proliferation, apoptosis and the levels of the main effector caspase, caspase-3 in the luteal in-phase and out-of-phase endometrium.MethodsThirty-seven endometrial samples from sterile or recurrent abortion patients were included in this study: 21 in-phase samples (controls) and 16 samples with out-of-phase endometrium. Biopsy specimens of eutopic endometrium were obtained from all subjects during days 21-25 of the menstrual cycle. The endometrium with endometrial maturity of cycle day 25 or less at the time of menstruation was considered out-of phase. Endometrial tissues were fixed in 10% buffered formaldehyde. For apoptosis quantification, sections were processed for in situ immunohistochemical localization of nuclei exhibiting DNA fragmentation, by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP digoxygenin nick-end labeling (TUNEL) technique. Expressions of Proliferating Cell Nuclear Antigen (PCNA) as a marker of cell proliferation, and of cleaved caspase-3 as a marker of apoptosis, were assessed by immunohistochemistry in the luteal in-phase and out-of-phase endometrium from infertile and recurrent abortion patients.ResultsLuteal out-of-phase endometrium had increased apoptosis levels compared to in-phase endometrium (p < 0.05). Caspase-3 evaluation confirmed these results: the luteal out-of-phase endometrium showed augmented cleaved caspase-3 expression (p < 0.005). As well, our data demonstrated that the luteal out-of-phase endometrium expresses decreased PCNA levels (p < 0.05), showing that cell proliferation is diminished in this tissue.Conclusionsthis study represents the first report describing variations at the cell proliferation and cell death levels in the out-of-phase endometrium in comparison with in-phase endometrium from infertile and recurrent abortion patients. Further studies are needed to elucidate a potential role of these alterations in the physiopathology of luteal phase deficiency.
Highlights
Various endometrial abnormalities have been associated with Luteal phase defect (LPD): a significant dyssynchrony in the maturation of the glandular epithelium and the stroma and a prevalence of out-of-phase endometrial biopsy specimens [1]
An increased apoptosis was detected in eutopic out-of-phase endometrium compared to in-phase controls: 57.1 ± 4.1 vs. 37.5 ± 5.6 expressed as percentage of TUNEL positive cells (p < 0.05, Figure 1B and 1C and Figure 2)
Immunohistochemistry for cleaved caspase-3 in in-phase and out-of-phase endometrium Complementary to the results obtained by the TUNEL method, the immunohistochemical staining using a specific antibody for the cleaved fragment of caspase-3 revealed increased immunoreactivity in epithelial endometrial cells from out-of-phase samples compared to inphase controls: 49.9 ± 4.2 vs. 23.0 ± 5.82 expressed as percentage of cleaved caspase-3 positive cells (p < 0.005, Figure 1E and 1F and Figure 3)
Summary
Various endometrial abnormalities have been associated with luteal phase deficiency: a significant dyssynchrony in the maturation of the glandular epithelium and the stroma and a prevalence of out-of-phase endometrial biopsy specimens. Out-of phase endometrium is a controversial disorder related to failed implantation, infertility and early pregnancy loss. Luteal phase defect (LPD) is a controversial syndrome believed to be related to failed implantation, infertility and early pregnancy loss [3,4,5,6]. In stimulated in vitro fertilization (IVF) cycles, the main cause of the LPD has been related to the multifollicular development achieved during ovarian stimulation [9]. Various endometrial abnormalities have been associated with LPD: a significant dyssynchrony in the maturation of the glandular epithelium and the stroma and a prevalence of out-of-phase endometrial biopsy specimens [1]. It is difficult to establish the exact incidence of out-of phase endometrium and of LPD because the assessment of histological dating is frequently subjective and lacks precision [10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
