Apoptosis in the human uterine endometrium during the menstrual cycle

Abstract

To investigate apoptotic changes, we studied the cleavage of DNA in the uterine endometrium obtained from regularly cycling women by a quantitative end labeling of DNA gel fractionation and in situ analysis. The ladder pattern characteristic of the apoptotic cleavage of DNA into fragments of low mol wt was identified at three different phases of the cycle, namely the early proliferative, late secretory, and menstrual phases. However, DNA of high mol wt was predominant in the endometrium during the late proliferative, early secretory, and midsecretory phases. Our analysis in situ revealed that cells undergoing apoptosis were scattered in the functional layer of the early proliferative endometrium. However, apoptotic cells were no longer detectable during the late proliferative phase, and none was observed until the midsecretory phase. At the beginning of the late secretory phase, apoptosis reappeared in the stromal cells and spread gradually to almost all components of the functional layer. By contrast, cells in the basal layer showed no evidence of apoptosis throughout the menstrual cycle. The present study demonstrates that apoptosis occurs in specific populations of cells during three phases of the human endometrial cycle. Our results indicate, moreover, that apoptosis might have an important role in the regulation of the menstrual cycle in women.

Endometrium from women with endometriosis shows increased proliferation activity

“…Apoptosis is markedly activated in the late secretory phase and decreases in the proliferative early secretory phase of the menstrual period in normal endometrial tissues. In contrast, apoptotic activity decreases in refluxed endometrial tissues during the late luteal and early proliferative phases of menstruation (15). In the present study, we observed the same result as others have described.…”

Apoptosis in the Porcine Uterine Endometrium During the Estrous Cycle, Early Pregnancy and Post Partum

“…The relationships between apoptosis and uterine physiology have been studied in some species [2][3][4][5][6]. A decrease in the height of the surface epithelium coincident with apoptosis from proestrus to midestrus in the rat [6] and strong apoptosis in the human uterus during the late secretory phase of the menstrual cycle [2] have been confirmed by TUNEL assay.…”

“…Dynamic changes in the uterine endometrium are a type of homeostasis and proceed with proliferation and exclusion of cells. Homeostasis of the uterus is closely related to apoptosis and involves various hormones and cytokines [1][2][3][4][5][6]. Structural changes in the human endometrium during the menstrual cycle have been studied from the viewpoint of apoptosis [2,3].…”

“…Homeostasis of the uterus is closely related to apoptosis and involves various hormones and cytokines [1][2][3][4][5][6]. Structural changes in the human endometrium during the menstrual cycle have been studied from the viewpoint of apoptosis [2,3]. Apoptotic features during the implantation window and early pregnancy in some species have been reported [7][8][9][10][11][12][13].…”

Class reunion: PTEN joins the nuclear crew

“…The effects of estrogen on the dynamics of activation and nuclear localization of AKT are again well described by the endometrial model system and reveal a strong inverse correlation between the presence of PTEN and active AKT in the nuclear compartment. The levels of active nuclear AKT in the glandular epithelium are low in the early proliferative phase, when the amount of nuclear PTEN is very high and selected cell populations undergo apoptosis (Kokawa et al, 1996) and then increase to peak in the late proliferative phase, when nuclear PTEN starts declining and proliferation is at its peak (Guzeloglu-Kayisli et al, 2003). In the secretory phase, when cells do not proliferate and prepare for apoptosis, nuclear AKT levels are very low, as are those of PTEN.…”