Decidua Of Early Human Pregnancy Research Articles

Increased IL-10-competent regulatory B cells in the decidua of early human pregnancy

Regulatory B cells (Bregs) may play a pivotal role in maintaining human pregnancy. For the first time, to the best of our knowledge, this study noted that cell percentages of CD24hiCD38hi Bregs and CD24hiCD27+ Bregs, which can potentially produce IL-10, are increased in human decidua compared with the mid-luteal phase endometrium. In each case of decidua, the correlation between Bregs and dendritic cell (DC) or natural killer (NK) cell expression was further explored. A positive correlation between the percentage of CD24hiCD38hi Bregs and CD123−CD11c+ myeloid DCs (mDCs) was noted. Furthermore, a significant positive correlation was also observed between the percentage of CD24hiCD27+ Bregs and CD94+CD56brightCD16− suppressive NK cells. These findings regarding decidual Bregs deepen the understanding of the harmonious immunological microenvironment that sustains early human pregnancy.

Localization of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitors for MMPs (TIMPs) in uterine natural killer cells in early human pregnancy

Invasion by extravillous trophoblast into uterine decidua and myometrium with remodeling of spiral arteries is essential for normal human pregnancy and is tightly regulated. Uterine natural killer (uNK) cells appear to be a major maternal regulator of placentation through the secretion of growth factors, cytokines and proteinases. Matrix metalloproteinase (MMP)-2 and MMP-9 activity in placental bed biopsies was studied using in situ gelatin zymography. Expression by uNK cells of MMP-2, MMP-9 and their tissue inhibitors, TIMP-1, TIMP-2 and TIMP-3, was localized in the placental bed by immunohistochemistry. Levels of MMP-2, MMP-9, TIMP-1, TIMP-2 and TIMP-3 secreted into 24 h cell culture supernatants of isolated uNK and unseparated (total) decidual cells (8-10 and 12-14 weeks gestation, n = 10 each group) were determined by gelatin gel zymography or western blot as appropriate. Gelatinase activity in situ appeared greater in decidua than myometrium. uNK cells showed strong immunostaining for MMP-2 and TIMP-2. MMP-9 activity was lower in uNK cells than total decidual supernatants (8-10 weeks: P = 0.0003; 12-14 weeks: P = 0.0012). In contrast, there was no difference in MMP-2 secreted by either uNK cell or total decidual cultures. uNK cells from early human pregnancy decidua possess innate protease activity, especially MMP-2, providing further evidence for a role for these cells in regulation of trophoblast invasion and spiral artery remodeling in early placentation.

BDCA-1+, BDCA-2+ and BDCA-3+ dendritic cells in early human pregnancy decidua

Dendritic cells (DCs) can acquire unique features or phenotypes in different tissue microenvironments and decide whether immunity or tolerance develops. DCs observed within the decidua have been implicated in pregnancy maintenance. However, the precise distribution of decidual DC subsets and their phenotypic characteristics are largely unknown. Using flow cytometry, we identified three DC subsets in normal human first-trimester decidua: BDCA-1+ CD19- CD14(-) myeloid DC type 1 (MDC1), BDCA-3+ CD14- myeloid DC type 2 (MDC2) and BDCA-2+ CD123+ plasmacytoid DC (PDC). The percentage of MDC1 to mononuclear cells in the decidua was similar to that in the peripheral blood controls. The percentage of MDC2 in the decidua was significantly higher than that in the peripheral blood controls, whereas the percentage of PDC was significantly lower. Both MDC1 and MDC2 subsets expressed human leucocyte antigen D-related, CD86 and CD80 at low levels, suggesting a characteristic of immature myeloid DCs. Immunoglobulin-like transcript 3, suggested to be involved in immune tolerance induction, was also expressed on decidual MDC1 and MDC2 subsets. In addition, as gestational age increased from 6 to 9 weeks, the numbers of MDC1 decreased but MDC2 increased significantly. This is the first study to demonstrate the presence of three previously unidentified BDCA-1+, BDCA-3+ and BDCA-2+ DC subsets in human decidua, these decidual DCs might play important role in the maintenance of pregnancy.

Decidual and peripheral blood CD4+CD25+ regulatory T cells in early pregnancy subjects and spontaneous abortion cases.

Human pregnancy represents a situation of semiallograft to maternal host. Therefore, it has been reported that tolerance to the fetal allograft represents a mechanism for maintaining a pregnancy. CD4(+)CD25(bright) regulatory T cells are known to play an important role in the development and maintenance of tolerance in peripheral tissues. However, the potential role of CD4(+)CD25(bright) T cells in maintaining human pregnancy has not been reported. In this study, we show that early human pregnancy decidua contains an abundance of CD4(+)CD25(bright) T cells, which express CD152(CTLA-4) at a high level. CD4(+)CD25(bright) T cells mediate potent inhibition of autologous T-cell proliferation by anti-CD3 stimulation. Furthermore, these cells inhibit the proliferation of autologous CD4(+)CD25(-) T cells in a dose-dependent fashion. This suppressive function of decidual CD4(+)CD25(+) T cells required cell-to-cell contact. The proportion of decidual CD4(+)CD25(bright) T cells was significantly lower in specimens from spontaneous abortion compared to those from specimens from induced abortions. These results suggest that decidual CD4(+)CD25(bright) T cells contribute to the mechanisms mediating maternal immune tolerance of conceptus antigens and therefore might contribute to the maintenance of pregnancy.

Cytokine secretion patterns of NK cells and macrophages in early human pregnancy decidua and blood: implications for suppressor macrophages in decidua.

Local immune modulation has been shown to be of considerable importance for the maintenance of successful pregnancy. We have previously reported the secretion of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cellular source of cytokine secretion in the decidua, and compare this to secretion patterns in peripheral blood. Decidual tissue and peripheral blood was collected from 20 women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were enriched by immunomagnetic cell separation and cytokine secretion was detected by enzyme-linked immunosorbent spot-forming cell assay. Decidual and peripheral monocytes/macrophages and NK cells spontaneously secrete IFN-gamma, IL-4 and IL-10. The number of IL-10 secreting cells was significantly higher in decidual macrophages compared with decidual non-monocytic cells as well as compared with blood monocytes/macrophages. These differences were not seen for IFN-gamma or IL-4. Our results indicate that decidual macrophages subserve important suppressive functions in the pregnant uterus.

Predominance of Th2-promoting dendritic cells in early human pregnancy decidua.

Dendritic cells (DCs) are specialized antigen-presenting cells required for the priming and activation of T cells and promote the differentiation of naïve CD4+ T cells toward the T helper cell type 1 (Th1) or Th2 phenotype. Here, we describe the characterization of CD45+CD3-CD14-CD16-CD19-CD20-CD56-HLA-DRbright DCs from early human pregnancy decidua by flow cytometry. The percentage of DCs to mononuclear cells (leukocytes) in the decidua was significantly higher than that in the peripheral blood. Moreover, decidual DCs expressed costimulatory molecules such as CD80 and CD86 and a mature marker such as CD83 on their surface. The percentage of CD11c+CD123- myeloid DCs in the decidua was significantly higher than that in the peripheral blood. Conversely, the ratio of CD11c-CD123+ lymphoid DCs in the decidua was significantly lower than that in the peripheral blood. The number of interleukin (IL)-12-producing cells in the total DC population and the myeloid DCs in the decidua was significantly lower than that in the peripheral blood. IL-12 secretion by activated decidual myeloid DCs was significantly lower than that by peripheral DCs. Naïve CD4+ T cells primed with decidual myeloid DCs led to a higher percentage of Th2 cells in comparison with that with peripheral myeloid DCs. This finding was abolished by exogenous IL-12 administration with decidual myeloid DCs. Thus, the DCs in the decidua could regulate the Th1/Th2 balance to maintain a Th2-dominant state, leading to maintenance of pregnancy.

Unique Appearance of Proliferating Antigen-Presenting Cells Expressing DC-SIGN (CD209) in the Decidua of Early Human Pregnancy

Intact human pregnancy can be regarded as an immunological paradox in that the maternal immune system accepts the allogeneic embryo without general immunosuppression. Because dendritic cell (DC) subsets could be involved in peripheral tolerance, the uterine mucosa (decidua) was investigated for DC populations. Here we describe the detailed immunohistochemical and functional characterization of HLA-DR-positive antigen-presenting cells (APCs) in early pregnancy decidua. In contrast to classical macrophages and CD83(+) DCs, which were found in comparable numbers in decidua and nonpregnant endometrium, only decidua harbored a significant population of HLA-DR(+)/DC-SIGN(+) APCs further phenotyped as CD14(+)/CD4(+)/CD68(+/-)/CD83(-)/CD25(-). These cells exhibited a remarkable proliferation rate (9.2 to 9.8% of all CD209(+) cells) by double staining with Ki67 and proliferating cell nuclear antigen. Unique within the DC-family, the majority of DC-SIGN(+) decidual APCs were observed in situ to have intimate contact with CD56(+)/CD16(-)/ICAM-3(+) decidual natural killer cells, another pregnancy-restricted cell population. In vitro, freshly isolated CD14(+)/DC-SIGN(+) decidual cells efficiently took up antigen, but could not stimulate naive allogeneic T cells at all. Treatment with an inflammatory cytokine cocktail resulted in down-regulation of antigen uptake capacity and evolving capacity to effectively stimulate resting T cells. Fluorescence-activated cell sorting analysis confirmed the maturation of CD14(+)/DC-SIGN(+) decidual cells into CD25(+)/CD83(+) mature DCs. In summary, this is the first identification of a uterine immature DC population expressing DC-SIGN, that appears only in pregnancy-associated tissue, has a high proliferation rate, and a conspicuous association with a natural killer subset.

A subset of CD56+ large granular lymphocytes in first-trimester human decidua are proliferating cells

Objective: To determine whether the unusually high number of CD56+ large granular lymphocytes (LGL) in the decidua of early human pregnancy arises from selective migration or in situ proliferation. Design: Controlled clinical study. Setting: Academic research environment. Patient(s): Thirty healthy women undergoing therapeutic abortion of an intact pregnancy at 5–11 weeks’ gestation. Intervention(s): Decidua was obtained by suction curettage; tissue and isolated cells were subjected to immunohistochemical and flow cytometric investigation. Main Outcome Measure(s): Proliferation rate of LGL. Result(s): The proportion of CD56+ cells positive for the proliferation-associated Ki-67 antigen was found to be 7%–23.5% by three different methods of investigation. These findings are consistent with those of flow cytometric analysis of the nuclear phase, which revealed 6%–22% of the LGL nuclei to be in the phases S+G 2+M. Conclusion(s): The various methods of investigation revealed marked proliferative activity in the LGL of early pregnancy decidua. This finding suggests that in situ proliferation may be responsible for the high density of these cells in the decidua.

Expression of tissue inhibitor of metalloproteinases-2 (Timp-2) in decidua of early human pregnancy: An immuno-histochemical study

Propranolol is a widely-known beta-blocker approved for treating infantile hemangiomas (IH). The mechanisms behind the spectacular IH involution after propranolol treatment remain unclear. Recently, there is strong evidence of overexpression of numerous angiogenic factors in IH tissues, and it is reported that propranolol influences their pathways. However, a number of MMPs studies is highly limited. Here, for the first time, we propose a comprehensive approach by analyzing the expression levels of metalloproteinases-2/9 (MMPs-2/9) and tissue metalloproteinase inhibitor-2 (TIMP-2) in vivo on both, molecular and immunohistochemical levels, and in both, IH tissues and in the serum of IH patients, and relates the obtained results to the tumor’s biology and systemic propranolol treatment.MMPs-2/9 and TIMP-2 were analyzed in 71 IH tissue samples using immunohistochemistry and real-time PCR, and in 50 serum samples of IH patients by ELISA.Significantly lower MMPs-2/9 and higher TIMP-2 levels were observed in IH tissues on the mRNA level as well as lower serum MMP-2 concentration among the treated individuals.MMPs-2/9 and TIMP-2 are both involved in the biology of IH and the propranolol pathways enabling their antiangiogenic properties. The most reliable method of IH examination appears to be direct MMPs-2/9 mRNA evaluation in tumor tissue; and MMP-2 evaluation in patients’ serum is a valuable complement to it. Tissue and serum mRNA MMPs assessment may represent a suitable novel biomarker identifying tumor progression and involution processes with potential clinical impact in IH as well as in cancer disease.

The decidua of early human pregnancy: immunohistochemistry and function of immunocompetent cells.

Like the endometrial stroma, the decidua contains lymphoreticular cells, and these are probably involved in immunological interactions between the conceptus and the mother. Lymphoreticular cells in decidual tissue obtained from 12 patients undergoing therapeutic abortion of an intact pregnancy at 6-10 weeks' gestation were investigated in this study. Immunophenotyping with a broad panel of monoclonal antibodies revealed various subpopulations of lymphoreticular cells. Macrophages (Ki-M6+, Ki-M7+, Ki-M8+, KP1+, MAC 387+ and Ki-M1P+) represented the largest fraction of intradecidual lymphoreticular cells. CD3+ and CD8+ lymphocytes were found in moderate numbers and CD4+ cells in small numbers. The majority of the intradecidual lymphoid cells exhibited an unusual phenotype [CD7+, CD2+, CD56+, triple negative (CD3-, CD4-, CD8)]. The distribution of these unusual lymphocytes mirrored that of the so-called endometrial stromal granulocytes. A few of these stromal granulocytes reacted with the macrophage-associated antibody KP1, but not with Ki-M1P, another macrophage marker. This was confirmed by immuno-electron microscopy. The finding that intradecidual CD3+ lymphocytes express neither the alpha/beta nor the gamma/delta heterodimer of the T cell antigen receptor was unexpected. However, these cells did express the alpha/beta heterodimer after in vitro culture with PHA-P and recombinant exogenous interleukin-2. No stimulated T lymphocytes expressing activation antigens could be detected. B lymphocytes, T and B immune accessory cells and CD15+ granulocytes were found only in small numbers or were absent. Amongst cells expressing NK cell markers, CD57+ and CD16+ cells were found in small to moderate numbers, while CD56+ cells were detected in large numbers.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between steroid receptor levels and prolactin level in the decidua of early human pregnancy

To clarify the relation between steroids and prolactin (PRL) production in human decidua, the levels of estrogen receptors (ERs), progesterone receptors (PRs), and androgen receptors (ARs) and the level of PRL in the decidua were determined simultaneously during early pregnancy. Cytosol, nuclear, and total ER levels and the cytosol PRL level were found to increase with the advance of gestation; whereas levels of PRs and ARs remained constant. Multiple regression analysis showed that the multiple correlation coefficient in the relationships of cellular ERs and cytosol PRL with gestational age was 0.722 and relatively high among the others. These results suggest an association between estrogen and decidual growth. Significant correlations between the cytosol PRL level and cellular PR or AR levels were seen during early pregnancy, suggesting that progestin and androgen may regulate PRL synthesis.