Association of mesenchymal cells and immunoglobulins with differentiating epithelial cells.

BACKGROUND: Mesenchymal-epithelial interactions play an important role in the physiology and pathology of epithelial tissues. Mesenchymal cells either associate with epithelium basement membrane [pericytes and perivascular monocyte-derived cells (MDC)] or reside within epithelium (MDC and T cells). Although intraepithelial mesenchymal cells were suggested to contribute to the epithelium physiology, their association with particular steps in differentiation of epithelial cells, interactions among themselves, and their fate remain unclear. We studied epitopes of mesenchymal cells and their products (immunoglobulins) in stratified epithelium of uterine ectocervix, which is one of the prototypes of complete cellular differentiation from stem into the aged cells. RESULTS: Perivascular CD14 primitive MDC associated with basal (stem) epithelial cells. Thy-1 pericytes of microvasculature secreted intercellular vesicles, which associated with Ki67 postmitotic epithelial cells expressing MHC class I. Intraepithelial T cells showed an association with veiled type MDC [dendritic cell (DC) precursors] among parabasal cells, and exhibited fragmentation after entering intermediate (mature) epithelial layers. Mature DC secreted CD68 and exhibited fragmentation after reaching mid intermediate layers. Binding of IgM was detected at the top of each layer: in the upper parabasal, upper intermediate, and most surface epithelial cells. IgG was confined to the entire superficial layer. CONCLUSIONS: These data suggest that the phylogenetically and ontogenetically developed hierarchy of mesenchymal cells (MDC, pericytes, T cells) and immunoglobulins (IgM, IgG) accompanies differentiation of epithelial cells from immature into the mature and aged phenotype. Further studies of an involvement of mesenchymal cells in the regulation of tissue homeostasis may bring novel approaches to the prevention and therapy of tissue dysfunctions characterized by permanent tissue immaturity (muscular dystrophy) or accelerated aging (degenerative diseases).

Ambulatory cervical ripening in term pregnancy.

OBJECTIVE: To study the safe use of Dilapan at term for ripening the unfavorable cervix in an outpatient setting. STUDY DESIGN: Prospective review of cervical ripening with Dilapan in women at term gestation. Such women were assigned to either outpatient or inpatient cervical ripening with Dilapan. RESULTS: Twenty-one patients were assigned to each group. The length of induction was similar between women who had ambulatory cervical ripening and hospitalized patients (11 +/- 7 vs. 14 +/- 7 hours, respectively), and the rates of chorioamnionitis, endometritis and nonreassuring fetal heart rate tracings were also similar. However, the average length of hospitalization was significantly shorter for those who had ambulatory ripening as compared to those who were hospitalized (51 +/- 27 vs. 70 +/- 20 hours, respectively; P < .0007). CONCLUSION: The use of Dilapan for cervical ripening at term in an ambulatory setting is safe and effective and may decrease the overall hospitalization time and cost.

Is irregular regression of corpora lutea in climacteric women caused by age-induced alterations in the "tissue control system"?

PROBLEM: We have recently observed that the regression of corpora lutea (CL) in women during the reproductive period of life is accompanied by a diminution of Thy-1 differentiation protein release from vascular pericytes and an accumulation of T lymphocytes and activated macrophages among both degenerating granulosa lutein cells (GLC) and theca lutein cells. These data suggest that the immune system and other stromal factors, representing components of the "tissue control system," may play a role in regression of the CL. We investigated degenerating CL from climacteric women to address the possibility that the decline of immune functions with advancing age may result in incomplete regression of luteal tissue. This could contribute to the altered hormonal profiles and abnormal uterine bleeding that frequently occur during the climacteric. METHOD: Immunoperoxidase staining and image analysis were used to localize Thy-1 differentiation protein of vascular pericytes, cytokeratin staining of GLC, neural cell adhesion molecule expression by theca lutein cells, CD15 of neutrophils, CD4, CD14, CD68, and leukocyte common antigens of macrophages, and CD3 and CD8 determinants of T lymphocytes. We also investigated the expression of luteinizing hormone receptor (LH receptor) and mitogen activated protein kinases (MAP kinases) in luteal cells. Samples of regressing luteal tissue were obtained during the follicular phase from perimenopausal women (age 45-50) who exhibited prolonged or irregular cycles. For comparison, luteal tissues from women with regular cycles (age 29-45) and CL of pregnancy were also investigated. RESULTS: Corpora lutea of the climacteric women exhibited irregular regression of luteal tissue characterized by a lack of cytoplasmic vacuolization and nuclear pyknosis in GLC, and by a persistence of theca lutein cells exhibiting hyperplasia and adjacent theca externa layers. This was accompanied by a continuing release of Thy-1 differentiation protein from vascular pericytes. Persisting GLC lacked surface expression of macrophage markers (CD4, CD14, CD68 and leukocyte common antigen) as well as nuclear granules exhibiting CD15 of neutrophils, detected in regularly regressing GLC. In addition, such persisting GLC showed weak or no LH receptor expression, and retained the expression of cytokeratin. They also exhibited enhanced staining for MAP kinases. Strong cytoplasmic MAP kinase expression with occasional nuclear translocation was also detected in persisting theca lutein cells, indicating high metabolic activity of these cells. T lymphocytes, although occasionally present in luteal stroma within luteal convolutions, did not invade among persisting GLC and were virtually absent from layers of theca externa and theca lutein cells. CONCLUSIONS: These data indicate that the regressing CL in climacteric women may exhibit persistence of luteal cells, perhaps because of age-induced alterations of the immune system and other local stromal homeostatic mechanisms involved in the elimination of luteal cells. Persisting GLC and/or theca lutein cells may exhibit abnormal hormonal secretion that contributes to the alteration of target tissues, such as the endometrium, resulting in abnormal uterine bleeding, hyperplasia, and neoplasia.

Platelet-derived growth factor promotes endometrial epithelial cell proliferation.

OBJECTIVE: Our purpose was to determine the effects of platelet-derived growth factor on the proliferation of endometrial epithelial cells. Platelet-derived growth factor and its receptors have been identified in the endometrium, and platelet-derived growth factor is a mitogen for endometrial stromal cells. Released from macrophages and platelets at sites of ectopic endometrial growth, platelet-derived growth factor could promote the progression of endometriosis and endometrial cancer. STUDY DESIGN: Endometrial epithelial cell lines were developed from proliferative-phase endometria from two patients without endometrial lesions. Cell lines were confirmed to be epithelial. Proliferation assays were conducted on both lines with recombinant human platelet-derived growth factor-AA, AB, and BB. Assays were also performed at different doses, times, and cell densities with platelet-derived growth factor. RESULTS: All isoforms of platelet-derived growth factor were potent mitogens for both endometrial epithelial cell lines. The greatest proliferative responses were achieved at 10 ng/ml and at 24 hours. Responses decreased significantly in confluent cultures. CONCLUSIONS: These results suggest that endometrial epithelial cells have functional platelet-derived growth factor-alpha receptors that signal cell replication. The greater activity of platelet-derived growth factor in subconfluent cultures may indicate that receptor numbers or affinity are up-regulated when cell-cell contact is disrupted. These data support a role for platelet-derived growth factor in normal endometrial proliferation and in pathologic proliferation such as endometriosis and endometrial cancer.

Is corpus luteum regression an immune-mediated event? Localization of immune system components and luteinizing hormone receptor in human corpora lutea.

Factors determining the life span of the human corpus luteum (CL) are not known. In addition to being determined by hormonal factors, such as hCG, the life of luteal cells may be determined by the preservation of luteal vascularization. Furthermore, the CL represents an immunologically unique tissue, as it is formed after menarche, long after adaptation of the immune system toward self. Thus, CL regression may be immunologically mediated. To determine what role the vasculature and immune system play in human CL development and regression, we examined immunohistochemically 1) the expression of Thy-1 differentiation protein by vascular pericytes, 2) the expression of major histocompatibility complex (MHC) class I and class II molecules in granulosa lutein cells (GLC), and 3) infiltration of the CL by macrophages and T lymphocytes. LH receptor (LHR) and cytokeratin 18 expression were also studied. In developing CL, the pericytes of luteal microvasculature released Thy-1 differentiation protein among the endothelial cells of proliferating vessels. In mature CL, Thy-1 released from vascular pericytes accumulated on the surface of GLC, and these cells exhibited LHR immunoreactivity (LHRI). Overall LHRI increased during the luteal phase and was strongest at the beginning of the late luteal phase. Although vascular pericytes showed strong LHRI, no staining of endothelium was detected during the luteal phase. GLC exhibited strong cytokeratin staining and moderate staining for MHC class I and MHC class II antigens; numerous macrophages were detected in luteal tissue. During pregnancy, the staining pattern was similar to that seen in the mature CL at the end of the midluteal phase. During the late luteal phase, surface expression of MHC class I and MHC class II antigens by GLC was substantially enhanced, and some T cells invaded among luteal cells. By the end of the cycle, an acute regression of vasculature and luteal tissue was observed along the fibrous septa. The remaining GLC showed only surface and no cytoplasmic LHRI. During the subsequent cycle, in the presence of numerous T cells, regressing GLC exhibited strong surface expression of various macrophage markers, such as CD4, CD14, CD68, and leukocyte common antigen, a feature not detected in the CL during the luteal phase nor described in other tissues. A complete loss of cytokeratin staining in GLC was observed. In regressing CL, strong LHRI was present in the endothelium of small and large luteal vessels. In conclusion, vascular pericytes and macrophages may stimulate the development and senescence of luteal tissue. The senescence of GLC may be inconsistent with preservation of luteal vasculature, and T lymphocytes appear to participate in terminal regression of the CL. Regression of luteal tissue therefore resembles immunologic rejection of a transplant. During pregnancy, the aging process of GLC appears to be interrupted, possibly due to the temporary acceptance of the CL "graft."

Immunohistochemical studies of the adult human ovary: possible contribution of immune and epithelial factors to folliculogenesis.

PROBLEM: Formation of primordial follicles in adult ovaries could be a cryptic process limited to relatively small areas of the ovarian cortex and occurring during a certain stage of the menstrual cycle. Such an event may require a specific milieu provided by factors involved in developmental processes, i.e., morphoregulatory molecules and macrophages. METHOD: Adult human ovaries were investigated by immunohistochemistry for surface epithelium and granulosa cell markers (cytokeratin 18 and MHC class I), immune system-related morphoregulatory molecules (Thy-1 glycoprotein and N-CAM), and macrophage phenotypes (CD14, CD68, and MHC class II). RESULTS: In some ovaries 300-500 microns areas of surface epithelium were overgrown by tunica albuginea, descended into the stroma, and apparently fragmented into individual small (20-40 microns) follicle-like cell nests. Differentiation of the surface epithelium was accompanied by macrophages and Thy-1 glycoprotein. Small segments of surface epithelium showed N-CAM and a lacked MHC class I expression. In such segments, clear spherical germ-like cells migrated into the deeper stroma, associated with the microvasculature, and eventually aggregated with follicle-like cell nests. CONCLUSIONS: Our data suggest that surface epithelium may be involved in the formation of some primordial follicles in adult ovaries. This process, and further follicular fate, may require a precise interplay of immune system related morphoregulatory molecules and macrophages.

Expression of cell cycle regulatory proteins (p53, pRb) in the human female genital tract.

PURPOSE: Recent studies have shown that proliferation and differentiation of various cell types is regulated by cell-cycle-related proteins, such as protein p53 and retinoblastoma protein pRb. METHODS: Three monoclonal antibodies to p53 (PAb240, PAb421, and PAb1801) and 3H9 monoclonal antibody to pRb were utilized for localization of proteins by peroxidase immunohistochemistry in frozen tissue sections. RESULTS: Nuclear and nucleolar p53 expression was detected in nondividing and relatively stable cells, e.g., oocytes in primordial follicles and granulosa lutein cells. On the other hand, strong cytoplasmic p53 expression was detected in proliferating and low differentiated epithelial cells of the ovarian surface epithelium, amnion, endocervix and ectocervix, indicating enhanced p53 synthesis. Not all three p53 antibodies reacted with each tissue, perhaps due to structural and conformational changes in the p53 molecule, accompanying p53 association with other proteins, e.g., tissue specific transcription factor interactions. pRb expression was usually restricted to the cell nuclei and nucleoli. However, glandular cells of the female reproductive tract showed cytoplasmic pRb expression in juxtaluminal (secretory) segments of cells, a feature not previously described in any cell type. p53 and pRb immunoreactivities declined with advanced differentiation of cells. No p53 or pRb was detected in placental syncytiotrophoblast or terminally differentiated squamous epithelial cells. CONCLUSION: Our data indicate that large quantities of p53 are synthesized in cells leaving the cell cycle and entering differentiation. Except in glandular cells, the pRb expression is confined to the cell nuclei and nucleoli. A unique cytoplasmic expression of pRb in juxtaluminal segments of glandular cells suggests a role for pRb in human female fertility and conception.

Histopathological changes in leiomyomata treated with leuprolide acetate.

Several studies have shown a decrease in uterine and/or leiomyoma volume when treated with leuprolide acetate (LA), a widely used gonadotropin-releasing hormone agonist. The mechanism by which these changes occur is unknown. In this study, the histopathological slides of 31 women of reproductive age who underwent hysterectomy or myomectomy were blindly reviewed by a pathologist. Seventeen women underwent myomectomy. Among those, 10 were treated with LA. The tumors in all of these patients were reduced in size after therapy. Histopathologically, the LA treatment correlated with a significant reduction in cellularity. No significant change in fibrosis, edema, or mitotic activity was seen.