Excess Heme Promotes the Migration and Infiltration of Macrophages in Endometrial Hyperplasia Complicated with Abnormal Uterine Bleeding.

In patients, endometrial hyperplasia (EH) is often accompanied by abnormal uterine bleeding (AUB), which is prone to release large amounts of heme. However, the role of excess heme in the migration and infiltration of immune cells in EH complicated by AUB remains unknown. In this study, 45 patients with AUB were divided into three groups: a proliferative phase group (n = 15), a secretory phase group (n = 15) and EH (n = 15). We observed that immune cell subpopulations were significantly different among the three groups, as demonstrated by flow cytometry analysis. Of note, there was a higher infiltration of total immune cells and macrophages in the endometrium of patients with EH. Heme up-regulated the expression of heme oxygenase-1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2) in endometrial epithelial cells (EECs) in vitro, as well as chemokine (e.g., CCL2, CCL3, CCL5, CXCL8) levels. Additionally, stimulation with heme led to the increased recruitment of THP-1 cells in an indirect EEC-THP-1 co-culture unit. These data suggest that sustained and excessive heme in patients with AUB may recruit macrophages by increasing the levels of several chemokines, contributing to the accumulation and infiltration of macrophages in the endometrium of EH patients, and the key molecules of heme metabolism, HO-1 and Nrf2, are also involved in this regulatory process.

Changes in subsets of immunocytes in endometrial hyperplasia.

PROBLEM: Endometrial hyperplasia (EH) is characterized by an endometrial gland-to-stroma ratio >1 and is one of the most common gynecological diseases in the world. The role of immunocyte subsets in the development of EH remains unknown. METHODS: Patients who underwent dilatation and curettage due to abnormal uterine bleeding were recruited in the present study. Alterations in the numbers of different types of immune cell subsets in the endometrium of patients were analyzed by flow cytometry. RESULTS: The present study included 48 patients who were divided into three groups, based on the pathological results: (a) proliferative period (PP, n = 12); (b) simple EH (SEH, n = 30); and (c) complex EH (CEH, n = 6). The results showed that immune cell subpopulations were significantly different between these three groups. Compared with the PP group, the proportion of CD45+ cells and neutrophils and the subtypes of T cells and macrophages were significantly increased in the SEH patients. Compared with the PP and SEH groups, subsets of immunocytes in the CEH group were significantly decreased, including the population of CD45+ cells and the subtypes of T cells and natural killer cells; in contrast, the proportion of macrophages was significantly increased. There were no significant differences between the other cell subsets in each group. CONCLUSION: The changes in immune cell subsets may be closely associated with the progression of EH. Although the specific role of different immune cell subsets in the development of the diseases requires further study, the changes in the proportions of immune cell subsets should not be ignored.

Decidual stromal cells promote the differentiation of CD56bright CD16- NK cells by secreting IL-24 in early pregnancy.

PROBLEM: Decidual stromal cells (DSCs) are important origins of cytokines to modulate maternal-fetal immunotolerance and provide a feasible environment for embryo implantation and development. Interleukin (IL)-24 is a multifunctional cancer killing cytokine and a pleiotropic immunoregulator with complex potency according to tissue or cell types. Its role in establishment and maintenance of normal pregnancy is largely unknown. The aim of our study was to investigate the function and significance of IL-24 and its receptor in the coordination between DSCs and natural killer cells (NK) in early pregnancy. METHOD OF STUDY: The levels of IL-24 in DSC, endometrial stromal cell (ESC), peripheral blood NK cells (pNK), or decidual NK cells (dNK) culture supernatants were detected by enzyme-linked immunosorbent assay (ELISA), and the levels of IL-24 receptors were determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry assays. The effect of IL-24 on the functions of decidual NK cells was analyzed by flow cytometry assays in vitro. RESULTS: The concentration of IL-24 in culture supernatant of DSCs was significantly higher than that of ESCs. Both eNK (endometrial NK cells) and dNK highly expressed IL-24 receptors (IL-20R1 and IL-22R1), especially on CD56dim eNK. However, there were extremely low levels of IL-20R1 and IL-22R1 on pNK. Recombinant human IL-24 or DSCs-secreted IL-24 downregulated the levels of CD16, Granzyme B, perforin, and interferon (IFN)-γ and upregulated the levels of inhibitory receptors killer-cell immunoglobulin-like receptor (KIR)2DL1 and KIR3DL1, or immunotolerant or angiogenic cytokines (eg, transforming growth factor (TGF)-ß, IL-10, and IL-8), and elevated the percentage of CD56bright CD16- dNK in vitro. CONCLUSION: These data suggest that DSCs promote the differentiation of CD56bright CD16- NK with high levels of inhibitory receptors, immunotolerant, and angiogenic cytokines by secreting IL-24 during decidualization in early pregnancy.