Kimitoshi Imai

Lymphocytes stimulate progesterone production by cultured human granulosa luteal cells

After follicular rupture, massive invasion of blood vessels with neovascularization of the developing corpus luteum takes place, providing many chances for direct contact of luteal cells with resident and migrating immune cells. We studied the effects of peripheral blood lymphocytes on progesterone production by human granulosa luteal cells isolated from women undergoing in vitro fertilization. During 6 days of culture, progesterone production by granulosa luteal cells was significantly increased when they were cultured together with autologous or allogenic peripheral blood lymphocytes. This stimulatory effect was also observed on the addition of medium conditioned with peripheral blood lymphocytes and was synergistic with gonadotropin stimulation. The activity was present in the fraction retained by ultrafiltration with a 30,000 molecular weight cutoff filter and was preserved after heating at 56 degrees C for 30 minutes but disappeared after heating at 70 degrees C for 15 minutes. These findings suggest that lymphocytes infiltrating the corpus luteum during early luteinization can stimulate the function of human granulosa luteal cells through the action of some protein-like humoral factor(s) of higher molecular weight than that of previously identified lymphokines and indicate a possible paracrinologic regulatory role for lymphocytes in ovarian function.

Expression and localization of aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV in the human placenta and fetal membranes

OBJECTIVE Our purpose was to determine the distribution of membrane-bound cell surface peptidases, namely aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV in the human placenta and fetal membranes. STUDY DESIGN Frozen tissue sections of the first-trimester chorionic villi, term placentas, and term fetal membranes were stained by indirect immunofluorescence with specific monoclonal antibodies. RESULTS In the first trimester chorionic villi cytotrophoblasts expressed both neutral endopeptidase and dipeptidyl peptidase IV, but syncytiotrophoblasts expressed only neutral endopeptidase. Stromal cells in the chorionic villi expressed the three peptidases at various intensities. In the term placentas villous syncytiotrophoblasts expressed neutral endopeptidase weakly, and the villous stromal cells expressed large amounts of both aminopeptidase N and dipeptidyl peptidase IV but neutral endopeptidase weakly or faintly. In the term fetal membranes amniotic epithelial cells and chorion laeve expressed both neutral endopeptidase and dipeptidyl peptidase IV. Decidual cells in the decidua parietalis moderately or highly expressed aminopeptidase N. CONCLUSION Three peptidases, aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV, are expressed by different cell populations in the human placenta and fetal membranes, suggesting their respective and important roles at the maternofetal interface.

Detection of antiendometrial antibodies in patients with endometriosis by cell ELISA

PROBLEM: To determine whether infertile patients with endometriosis have serum antiendometrial antibodies.

Small Cell Undifferentiated Carcinoma of the Uterine Cervix: Histology, Ultrastructure, and Immunohistochemistry of Two Cases

Two clinical stage IB small cell undifferentiated carcinomas (SCUC) of the cervix were studied by light and electron microscopy and immunohistochemistry. Both cases occurred in women aged less than 31 years. Despite radical hysterectomy and external pelvic radiotherapy, both patients died of recurrent disease within 14 months after initial therapy. The tumors consisted of sheets of closely packed, uniform small, round to oval cells with hyperchromatic nuclei and scant indistinct cytoplasm. One case was associated with cervical squamous cell carcinoma. The neoplastic cells had few organelles and desmosome-like junctions and lacked mucinous or neurosecretory granules or tonofilaments. Immunohistochemistry failed to reveal S-100, CEA, neuropeptides or neuron-specific enolase. SCUC probably arises either from basal cells of the cervical squamous epithelium, or gland cells of the endocervical epithelium, or still from subcolumnar endocervical reserve cells. Based on ultrastructure and immunohistochemistry, SCUC seems to represent the undifferentiated variant of small cell neuroendocrine tumors of the cervix.

Reduction of lnterleukin-2-Receptor Expression on Retroplacental Blood Lymphocytes in Human Pregnancy

ABSTRACT: Retroplacental blood lymphocytes (RPL) in human pregnancy were studied for proliferative response induced by recombinant interleukin‐2 (rIL‐2) and anti‐Tac positive cells before and after PHA stimulation for 24 hr and compared with peripheral blood lymphocytes (PBL) of the same donor. Proliferation of RPL induced by IL‐2 was significantly lower than that of PBL in all of six cases. In addition, flow cytometry analysis of IL‐2 receptors (IL‐2R) revealed that IL‐2R expression of RPL after stimulation with PHA for 24 hr was significantly less than that of PBL in three of four cases and that RPL showed significantly fewer IL‐2R than PBL even at resting state in one case. These results suggest that RPL seem likely to be composed of reduced numbers of lymphocytes bearing IL‐2R of non‐Tac protein and to have impaired capacity for the acquisition of high‐affinity receptors for IL‐2.

Endometrial stromal cell decidualization inhibits human chorionic gonadotropin and human placental lactogen secretion by co-cultured trophoblasts

We have developed an in-vitro co-culture system to examine the interaction between purified first trimester cytotrophoblasts and purified non-pregnant human endometrial stromal cells (ESC). ESC decidualization is an important step in endometrial maturation and may modulate embryo implantation. In order to investigate the effects of ESC decidualization on trophoblast function, we examined human chorionic gonadotrophin (HCG), human placental lactogen (HPL), progesterone and estrogen secretion by trophoblasts co-cultured in contact with ESC, either with or without decidualization induced by progesterone. Decidualized ESC inhibited basal HCG and HPL secretion for 3 days during the culture for HCG, and for 5 days during the culture for HPL (P < 0.01 and P < 0.03 respectively). After 5 days of co-culture, decidual transformation of ESC as indicated by prolactin production occurred in the control cultures due to progesterone and oestradiol secretion by the co-cultured trophoblasts, but no significant differences in HCG or HPL secretion were observed between the two groups. Although the type of trophoblast used in the present study is far from implantation, our results clearly demonstrated that HCG and HPL secretion by trophoblasts was inhibited by the presence of co-cultured decidualized ESC, and suggested that ESC decidualization may regulate trophoblast function at the human fetal-maternal interface.

The Expression of Peptidase Antigens, CD10/Neutral Endopeptidase, CD13/Aminopeptidase N, and CD26/Dipeptidyl Peptidase IV in Human Endometrium

Peptidase enzymes are known to be widely distributed in plasma and tissues. As such, they are considered to play important roles in the local regulation of biologically active peptides, including peptide hormones, growth factors, and cytokines. In the uterine endometrium, it has been suggested that some peptidase enzymes in the endometrial epithelium play an important role in blastocyst implantation. In rabbits, the uterine epithelium undergoes extensive morphological change during the peri-implantation phase, and dynamic changes in aminopeptidase and dipeptidyl peptidase IV activities on the surface of endometrial epithelial cells have been reported in histochemical experiments (Classen-Linke et al., 1987). Furthermore, proteinase inhibitors have been shown to block implantation in rabbits (Denker, 1977). In humans, we have reported that the cluster of differentiation (CD) antigens, CD10 and CD13, were expressed in the endometrial stromal cells, and that CD26 antigens were localized in the glandular epithelial cells (Imai et al., 1992a, 1992b). CD10, CD13, and CD26 antigens were shown to be identical to neutral endopeptidase (NEP) (Letarte et al, 1988), aminopeptidase N (APN) (Look et al. 1989), and dipeptidyl peptidase IV (DPP IV) (Mattern et al., 1989; Stein et al., 1989;Ulmer et al., 1990) respectively, all of which are cell surface peptidases. Since a variety of peptide factors, including peptide hormones, growth factors, and cytokines, have been suggested to play important roles in regulating endometrial cell proliferation/differentiation, these peptidase enzymes are thought to be involved in the regulation of human endometrial function and the implantation process.