Identification of activated T cell receptor gamma delta lymphocytes in the liver of tumor-bearing hosts.

T cell receptor (TcR)gamma delta cells are known to be a minor population of T lymphocytes in the blood (less than 10%) and other peripheral lymphoid organs in healthy donors. We demonstrated here that a large proportion of TcR gamma delta cells, i.e., up to 30% of mononuclear cells (MNC) were detectable in the liver, but not other lymphoid organs of cancer patients. More importantly, the majority of such TcR gamma delta cells (greater than 70%) were shown to be lymphoblastic by electron microscopy. An activation marker of T lymphocytes, Leu-19 (CD56) was also highly expressed on the hepatic TcR gamma delta cells. The possibility of hepatic TcR gamma delta cells being activated was further examined in mice. C3H/He mice injected with syngeneic tumor cells were demonstrated to have an increased number of liver MNC; such MNC showed an ability to proliferate in vitro. These mice eventually had a considerable proportion of TcR gamma delta cells in the liver, showing activation markers, the Ia and LFA-1 antigens. These results suggest that the liver may be an important organ for activation and probably expansion of TcR gamma delta cells especially in tumor bearing hosts.

Induction of pituitary tumors in germ-free rats exposed to Aspergillus versicolor.

We clarified the role of mold exposure in pituitary tumor induction using 53 germ-free Wistar rats exposed before birth and continually exposed thereafter, to Aspergillus versicolor alone. Rats were autopsied at 540 to 730 days. Untreated germ-free controls were autopsied on day 730. Thirty-three of the 53 monoassociated rats had pituitary tumors (62.3%), while only three of the 41 control germ-free rats had tumors (7.3%). It seems likely that this high incidence of pituitary tumor in the experimental rats is due to metabolites derived from the mold.

Immunoelectron microscopic localization of transforming growth factor beta 1 and latent transforming growth factor beta 1 binding protein in human gastrointestinal carcinomas: qualitative difference between cancer cells and stromal cells.

Transforming growth factor beta 1 (TGF-beta 1) is secreted as an inactive complex associated with latent TGF-beta 1 binding protein (LTBP). Tissue localization of these proteins has not been fully understood in human pathological conditions. We examined the immunohistochemical localization of TGF-beta 1 precursor (proTGF-beta 1) and LTBP in carcinomas and granulation tissue in the human gastrointestinal tract at the light and electron microscopic levels. In normal tissue, endothelial cells and granulocytes sporadically showed immunoreactivity for proTGF-beta 1, while epithelial cells were all negative. In cancer tissue, both cancer cells and stromal cells (fibroblasts, macrophages, and endothelial cells) were positive for proTGF-beta 1, more frequently in diffuse-type gastric carcinomas than in differentiated-type adenocarcinomas. Immunoelectron microscopy revealed that proTGF-beta 1 was localized in rough endoplasmic reticulum and perinuclear cisternae in fibroblasts, macrophages, and endothelial cells in cancer stroma and in fibrous granulation tissue. In contrast, the intracellular localization of proTGF-beta 1 in carcinoma cells was predominantly observed in the cytosol (cytoplasmic matrix). This finding suggests disarranged or blocked intracellular transportation of proTGF-beta 1 in cancer cells. The immunoreactivity for LTBP was not observed in the normal epithelial cells. It was localized in cancer stroma, not in cancer cells. Ultrastructurally, LTBP was located in the extracellular matrix around fibroblasts and smooth muscle cells. The intracellular immunoreactivity for LTBP was observed in rough endoplasmic reticulum of fibroblasts and smooth muscle cells, the same as in granulation tissue. These results suggest that gastrointestinal carcinoma cells produce no or a small amount of LTBP in vivo. Our investigation suggests that extensive fibrosis in both cancer stroma and granulation tissues may be promoted by TGF-beta 1 mainly secreted from stromal cells.

CD8+ T cells infiltrated within cancer cell nests as a prognostic factor in human colorectal cancer.

The pathophysiological significance of tumor infiltrating lymphocytes remains controversial. To clarify their role, we performed clinicopathological analysis of CD8+ T cells in 131 cases of human colorectal cancer. CD8+ T cells were classified into three groups by their localization: (a) those infiltrated within cancer cell nests; (b) those distributed in the cancer stroma; and (c) those present along the invasive margin (tumor-host interface). Of these, CD8+ T cells within cancer cell nests were most significantly associated with a better survival of patients by both mono- and multivariate analyses. The impact on survival was similar to that of Dukes' staging. Granzyme B+ cytoplasmic granules were detected in lymphocytes within cancer cell nests, confirming their activated, cytotoxic phenotype. CD8 and Ki-67 double immunohistochemistry confirmed higher proliferative activity of CD8+ T cells within cancer cell nests. Our data suggested that human colorectal cancer tissue was infiltrated by various numbers of T cells that had cytotoxic phenotype, contributing to a better survival of patients. This infiltration of colorectal cancer cell nests by CD8+ T cells could be a novel prognostic factor.

Proliferative activity of intratumoral CD8(+) T-lymphocytes as a prognostic factor in human renal cell carcinoma: clinicopathologic demonstration of antitumor immunity.

Tumor-infiltrating lymphocytes, particularly CD8(+) T cells, could be a manifestation of antitumor immunity. We clinicopathologically analyzed the biological significance of tumor-infiltrating lymphocytes in 221 patients with renal cell carcinoma without preoperative treatments. More abundant infiltration of tumor tissue not only by CD8(+) but also CD4(+) T cells was associated with shorter survival of the patients, because of the positive correlation between the number of lymphocytes and representative tumor grade factors. This suggests that immune cell reactions are more pronounced as the tumor grade/biological malignancy progresses, probably because of increased antigenicity of tumor cells. We next analyzed the proliferative activity of CD8(+) T cells that infiltrated in tumor cell nests, which could also reflect antitumor immunity. Higher labeling index of Ki-67, a proliferation-associated antigen, among CD8(+) T cells in contact to tumor cells was associated with a longer survival by both uni- and multivariate analyses. Our data in human renal cell carcinoma suggest that infiltration of tumor tissue by T cells itself does not denote the efficacy of antitumor immunity because of its dependence on the biological malignancy of tumor cells, but infiltration of tumor tissue by CD8(+) T cells bearing more pronounced proliferative activity could reflect effective antitumor immunity. This concept would be important for future immunotherapy of human cancer.

Aromatase in human bone tissue.

Peripheral aromatization of androgens exert estrogenic actions in many tissues. Recently in situ production of estrogens by aromatase was detected in human bone and cultured osteoblasts and has been proposed to participate in the maintenance of bone mass. We examined aromatase expression by immunohistochemistry and mRNA in situ hybridization in 16 cases of tibia (female 2 male, 14 female, 62 +/- 5.2 years old) and quantified the level of aromatase mRNA in 28 cases of rib, femur, and lumbar vertebrae (16 male, 12 female, 58.0 +/- 11.3 years old) by reverse transcriptase-polymerase chain reaction (RT-PCR) in order to study whether or not and in which cell types aromatase was expressed in human bone tissues. We also studied alternative use of multiple exons 1 of its gene and immunolocalization of type I 17 beta-hydroxysteroid dehydrogenase (HSD), which converts estrone produced by aromatase to estradiol. Strong aromatase immunoreactivity and mRNA hybridization as well as type I 17 beta-HSD immunoreactivity were detected in lining cells, osteoblasts, chondrocytes of articular cartilage, and adipocytes adjacent to bone trabeculae in all the cases examined. Amounts of aromatase mRNA varied greatly among the subjects (11.25 +/- 9.77, 0.61-42.84 attomol/ng of total RNA). The amount of aromatase expression was not correlated with age or gender of the subjects but positively correlated with the degree of osteroporotic changes evaluated by radiological findings of lumbar vertebrae. Analysis of multiple exons 1 revealed that 1b or fibroblast type was predominantly (23/26) utilized as a promoter of aromatase gene expression. These results demonstrated that aromatase is expressed widely in human bone tissue and may play important roles in maintenance of human bone tissue.

Identification of secretory immunoglobulin A in human sweat and sweat glands.

Secretory immunoglobulin A (sIgA) plays an important role in local immune defense mechanisms. Although skin is always exposed to external antigens, the role of local immune defenses involving sIgA in the skin has not been adequately studied. In order to evaluate the presence of sIgA in sweat, we have measured the concentration of sIgA in human sweat by enzyme immunoassay and have localized the components of sIgA in the sweat glands of human axillary skin. The concentration of sIgA in sweat was found to be 10 times higher in men than in women (13.0 +/- 0.9 micrograms/ml versus 1.6 +/- 0.9 micrograms/ml). Secretory component (SC) was localized immunohistochemically in protein synthetic organelles, such as the perinuclear spaces and Golgi complex, in cytoplasmic vesicles, and along the external surface membranes of mucous cells on the terminal segment of eccrine sweat glands. IgA and J chain were present in plasma cells in the protein synthetic organelles. The luminal aspects of eccrine sweat ducts also strongly express SC, as well as IgA and J chain. Neither SC, IgA, or J chain were identified in epithelial cells of apocrine sweat glands. These findings are consistent with the theory that J chain complexed with dimeric IgA is synthesized in plasma cells and is transported by SC-mediated endocytosis transfer across mucous cells of eccrine sweat glands and thus into sweat.

Aromatase and steroid receptors in gynecomastia and male breast carcinoma: an immunohistochemical study.

Hormonal factors have been implicated in the development of male breast disorders, including carcinoma and gynecomastia. We studied the expression of aromatase and estrogen (ER), progesterone (PR), and androgen (AR) receptors by immunohistochemistry in male breast carcinoma (15 cases) and gynecomastia (30 cases) to evaluate their possible significance in these disorders. Relatively strong aromatase immunoreactivity was observed in all cases of carcinoma, but in only 11 of 30 cases (37%) of gynecomastia. ER and PR expression was observed in the nuclei of ductal cells in all the cases of gynecomastia. More than 10% of the carcinoma cells were positive for ER and PR in 9 of 15 (60%) and 10 of 15 (67%) carcinomas, respectively. AR immunoreactivity was observed in nuclei of both epithelial and non-epithelial cells. AR was present in ductal or carcinoma cells in 13 of 15 (87%) cases of carcinoma and in all 30 (100%) cases of gynecomastia. The mean percentage of ER-, PR-, and AR-positive cells were significantly higher in gynecomastia than in carcinoma. There was a close association of AR with ER (P < 0.01) and PR (P < 0.01) in cases of gynecomastia, but there was a significant inverse correlation between AR and ER (P < 0.01) or PR (P < 0.05) expression in carcinoma cases. Increased aromatase expression in the stromal cells is considered to contribute to the increment in the in situ estrogen concentration and the development of male breast carcinoma.

Ad4BP in the human adrenal cortex and its disorders.

Ad4BP, a zinc finger DNA-binding protein, is a transcription factor that regulates the expression of the steroidogenic P450 genes. We performed immunoblotting and immunohistochemistry of Ad4BP in 34 human adrenal cortex specimens, which included adrenocortical adenomas and carcinomas. Immunoblotting revealed a single band of 53K, corresponding to the mol wt of Ad4BP. The immunohistochemical studies demonstrated that Ad4BP immunoreactivity was present exclusively in the nuclei of nearly all of the adrenocortical parenchymal cells in both the normal and the pathological human adrenal specimens. Ad4BP was immunostained with equal intensity and frequency among the different cell types. Ad4BP immunoreactivity was also observed in areas of marked degenerative changes, such as lipomyelomatous lesions, and in poorly differentiated carcinoma cells. These results suggest a close association of Ad4BP expression with the biological phenotype of adrenocortical parenchymal cells. Ad4BP therefore seems to play important roles in the induction and maintenance of the transcription of all steroidogenic P450 genes in human adrenocortical cells, even after malignant transformation.

Expression and cellular localization of estrogen receptors alpha and beta in the human fetus.

Estrogens exert various biological effects by acting through their native receptors, two of which have been identified to date: estrogen receptors alpha (ERalpha) and beta (ERbeta). In this study we examined the expression and cellular localization of ERalpha and ERbeta in various human fetal tissues by semiquantitative RT-PCR (13 and 20 gestational weeks) and immunohistochemistry (13, 20, and 38 gestational weeks), respectively, to study the possible effects of estrogens on human fetal tissues during development. Relatively high levels of ERbeta expression were detected in various human fetal tissues, whereas those tissues expressing ERbeta had markedly lower levels of ERalpha expression. ERbeta messenger ribonucleic acid expression was especially high in the adrenal gland. ERbeta-immunoreactive protein was localized to the definitive zone, but not in the fetal zone, of the adrenal cortex. Although low levels of ERbeta messenger ribonucleic acid were present in the brain, heart, lung, and kidney, ERbeta immunoreactivity was not detected in these tissues. These results suggest that the effects of estrogens in these tissues are predominantly mediated through ERbeta. ERbeta immunoreactivity was detected in Sertoli cells and spermatogonia in the male reproductive tract and in germ cells in the fetal testis and epididymis. In the female reproductive tract, both ERalpha and ERbeta were immunopositive in epithelium of the oviduct. The results of the present study have demonstrated the possible sites for estrogenic action in the human fetus and suggest that the effects of estrogen via ERbeta may play important roles in human fetal development, especially in the definitive zone of the adrenal cortex, and in the reproductive tissues of the developing fetus.

Messenger ribonucleic acid in situ hybridization analysis of estrogen receptors alpha and beta in human breast carcinoma.

We examined the expression of a recently characterized novel estrogen receptor (ER) beta in 25 cases of invasive ductal carcinoma of the breast, using messenger RNA (mRNA) in situ hybridization, and compared the findings with those of ERalpha, to study its localization and its possible biological significance in human breast cancer. ERalpha and ERbeta hybridization signals were both detected, predominantly in carcinoma cells and in some stromal cells, in 18 of 25 (72%) and 11 of 25 (44%) cases, respectively. The cases in which more than 25% of carcinoma cells demonstrated mRNA hybridization signals were 13 of 25 (52%) and 2 of 25 (8%) cases for ERalpha and ERbeta, respectively. Among the cases expressing ERbeta, 10 of 11 (91%) also expressed ERalpha mRNA; and in these 10 cases, coexpressing both ERalpha and beta, the number of carcinoma cells expressing ERalpha was greater than that expressing ERbeta in 9 cases. Eight cases demonstrated only ERalpha mRNA hybridization signals in carcinoma cells. These results indicate that ERbeta is coexpressed with ERalpha in most ERbeta-positive breast carcinoma cells, which suggests that the expression of ERbeta depends on the presence of ERalpha in the great majority of human breast cancer. In addition, the number of carcinoma cases and/or the ratio of carcinoma cells expressing ERalpha was much greater than those expressing ERbeta. The relative ratio of ERalpha and ERbeta expression in carcinoma cells may be related to various estrogen-dependent biological features of human breast cancer.

17Beta-hydroxysteroid dehydrogenase types 1 and 2 in human placenta: an immunohistochemical study with correlation to placental development.

In estrogen metabolism, the enzymatic properties of the 17beta-hydroxysteroid dehydrogenase (17betaHSD) isozymes play very important roles in steroid hormone metabolism in various tissues, including the placenta. 17betaHSD type 1 catalyzes primarily the reduction of estrone (E1) to estradiol (E2), whereas 17betaHSD type 2 catalyzes primarily the oxidation of E2 to E1. In this study, we examined immunohistochemical localization of 17betaHSD types 1 and 2 in human placenta (31 cases) ranging from 4-40 weeks gestation. The immunoreactivity of 17betaHSD type 1 was exclusively detected in syncytiotrophoblast from 4 weeks gestation to term placenta. Immunoreactivity of 17betaHSD type 2 first appeared in endothelial cells of intravillous vessels at 12 weeks gestation, and the number of 17betaHSD type 2-positive endothelial cells markedly increased up to 19 weeks, then reached a plateau. We quantitatively evaluated the 17betaHSD type 2-positive endothelial cells in chorionic villi and determined the ratio of 17betaHSD type 2-positive endothelial cells using immunohistochemistry of CD34, an endothelial antigen, in serial mirror tissue sections and subsequent image analysis using CAS 200. CD34 was detected from 4 weeks gestation, and its positive areas continued to increase toward term. The 17betaHSD type 2-positive area per CD34-positive area markedly increased from 13 weeks gestation and reached a plateau at 19 weeks gestation, in which almost all endothelial cells were positive for 17betaHSD type 2. 17BetaHSD type 2, therefore, is considered to prevent the passage of excessive estrogens into the fetal circulation at endothelial cells of the intravillous fetal capillaries by catalyzing the inactivation ofE2 to E1.

11Beta-hydroxysteroid dehydrogenase type 2 in human lung: possible regulator of mineralocorticoid action.

11Beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2) catalyzes the conversion of cortisol to biologically inactive cortisone and is thought to confer specificity on mineralocorticoid receptors (MR). Cortisol is a prerequisite for surfactant synthesis and fetal lung maturation. Recently, expression of 11betaHSD2 was demonstrated in human fetal lung, but its localization and possible biological roles remain unknown. Therefore, in this study, we examined immunohistochemical localization of 11betaHSD2, MR, and glucocorticoid receptor (GR) in nonpathological human lungs from fetus to adult (8 weeks gestation to 55 yr of age; n = 40) retrieved from pathology files. Both 11betaHSD2 and MR immunoreactivities were detected in airway epithelia, from bronchiole to trachea and in fetal and neonatal ciliated collecting duct cells of tracheal and bronchial glands, but were undetectable in alveoli. On the other hand, GR was detected in all cell types. These results indicate that 11betaHSD2 colocalizes with MR in human airway epithelia and suggest that 11betaHSD2 play an important role in pulmonary mineralocorticoid activity such as sodium and fluid transport.

11Beta-hydroxysteroid dehydrogenase type 2 and mineralocorticoid receptor in human fetal development.

11Beta-Hydroxysteroid dehydrogenase type II (11betaHSD2) confers specificity on the mineralocorticoid receptor (MR) by converting biologically active glucocorticoids to inactive 11-keto metabolites. The biological significance of 11betaHSD2 activity during fetal development is currently being explored, but the temporal and spatial distributions of the enzyme and receptor have not been examined. We therefore examined their distributions during various stages of human fetal development using immunohistochemistry. Both 11betaHSD2 and MR immunoreactivity were detected in the distal convoluted and collecting tubules of the kidney from early in gestation. Fetal skin, intermediate layer of the epidermis, peridermal cells, and hair follicles were positive for both 11betaHSD2 and MR. Weak 11betaHSD2 and MR immunoreactivity was detected in the superficial ciliated epithelium of the esophagus, the deep layer of gastric epithelial cells, and the superficial epithelium of the small intestine. Columnar epithelium in the terminal bronchiolar budding component of fetal lung and tracheal and bronchial ciliated epithelium were also positive for MR and 11betaHSD2 from early gestation. Colonic epithelium and pancreatic exocrine duct cells, which demonstrated marked immunoreactivity of both MR and 11betaHSD2 in the adult, did not express MR and 11betaHSD2 until very late in gestation. These results imply that mineralocorticoid action in the upper fetal gastrointestinal tract, kidney, skin, and lung is facilitated by 11betaHSD2 and is involved in water and electrolyte transport between fetus and amniotic fluid as well as fetal urine production.

Coexpression of mineralocorticoid receptors and 11beta-hydroxysteroid dehydrogenase 2 in human gastric mucosa.

The role of mineralocorticoids in human gastrointestinal tract is well established. In the stomach, aldosterone is thought to regulate electrolyte transport associated with gastric acid secretion. In mineralocorticoid target organs, the action of the glucocorticoid inactivating enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) facilitates aldosterone binding to a nonselective mineralocorticoid receptor (MR) in the face of high levels of circulating glucocorticoids. In the present study, we examined 25 specimens of human stomach for the presence of MR and 11beta-HSD2 using a [3H]aldosterone binding assay, Northern blot analysis, RT-PCR, and immunohistochemistry. Specific [3H]aldosterone binding sites were detected in gastric fundic mucosa, but not in the antrum. In fundic mucosa the Kd was 0.72+/-0.05 nmol/L (mean +/- SE), and Bmax was 6.0+/-1.4 fmol per milligram of protein. Northern blot analysis demonstrated a faint band for MR mRNA at 6.0 kb, although message for 11beta-HSD2 was undetectable. However, RT-PCR demonstrated specific PCR products for both MR and 11beta-HSD2. Immunohistochemistry demonstrated the colocalization of MR and 11beta-HSD2 only in parietal cells. MR-positive cells were further characterized by electron microscopy, confirming the identity of parietal cells. This study shows that parietal cells contain both MR and 11beta-HSD2, suggesting that the human stomach is a novel target organ for mineralocorticoids. Aldosterone may, therefore, regulate biological functions of parietal cells including gastric acid secretion.

Urocortin expression in human pituitary gland and pituitary adenoma.

Urocortin is a recently identified neuropeptide of the CRF family in the mammalian brain, but its expression in human tissue has been little studied. In this study, we examined urocortin expression in human anterior pituitary gland and pituitary adenomas by RIA, high performance liquid chromatography, immunohistochemistry, messenger ribonucleic acid (mRNA) in situ hybridization, and reverse transcriptase-PCR. Immunoreactive urocortin concentrations in normal pituitary tissue extract were 103.25 +/- 39.05 ng/g wet wt (mean +/- SEM; n = 4), and their levels were all significantly higher than those in other portions of central nervous system of the same subjects. High performance liquid chromatography analysis of human pituitary extract demonstrated a single peak corresponding to that of the expected chromatographic mobility of synthetic human urocortin-(1-40). Urocortin-immunoreactive cells were detected in the anterior pituitary gland. Neither urocortin-immunoreactive nerve fibers nor cells were detected in the posterior lobe. Immunostaining in serial mirror tissue sections revealed that 76.55 +/- 3.06% of urocortin-immunoreactive cells expressed GH immunoreactivity, whereas 22.25 +/- 3.02% and less than 1% of urocortin-immunoreactive cells expressed PRL and ACTH, respectively. mRNA hybridization signals of urocortin were also detected in urocortin-immunopositive pituitary cells. The reverse transcriptase-PCR analysis demonstrated a 145-bp RNA band corresponding to that of the expected length of urocortin in all cases of normal pituitary glands examined (n = 3). We also immunostained urocortin in 52 cases of human anterior pituitary adenomas, including GH-producing adenomas (n = 14), ACTH-producing adenomas (n = 13), PRL-producing adenomas (n = 11), and nonfunctioning hormonally inactive adenomas (n = 14). No urocortin immunoreactivity was detected in these adenoma cells, except for one case of GH-producing adenoma and one case of nonfunctioning adenoma. We also performed mRNA in situ hybridization in 27 adenomas. No hybridization signals were detected in these adenomas, except in two cases. The results described above indicated that urocortin is synthesized in human anterior pituitary cells and may play an important role in biological features of normal pituitary gland, possibly as an autocrine or a paracrine regulator

Colocalization of 11 beta-hydroxysteroid dehydrogenase type II and mineralocorticoid receptor in human epithelia.

The enzyme 11 beta-hydroxysteroid dehydrogenase type II (11 beta HSD2) has been shown to confer specificity on mineralocorticoid receptors (MR) by inactivating glucocorticoids. In the present study we examined the colocalization of 11 beta HSD2 and MR in various exocrine and secretory glands by immunostaining of serial mirror tissue sections with subsequent computerized image analysis. Both 11 beta HSD2 and MR proteins were expressed in the same cells in the distal convoluted tubules, Henle's loop, and collecting tubules of the kidney and the absorptive epithelia of duodenum, jejunum, ileum, colon, and excretory ducts of anal and esophageal glands. Significantly, 11 beta HSD2 and MR immunoreactivity also colocalized in the respiratory tract, in collecting ducts of the tracheal and bronchial glands, ciliated bronchial epithelial cells, and type II alveolar epithelial cells, suggesting important and unexpected roles for mineralocorticoids in the lung. In the skin, 11 beta HSD2 and MR were present only in excretory ducts of eccrine sweat glands, but not in sebaceous or apocrine glands. In eccrine glands, MR immunoreactivity was present in the basal cells of excretory ducts, while 11 beta HSD2 immunoreactivity was localized in the luminal cells. Neither 11 beta HSD2 nor MR proteins were expressed in the lacrimal gland, prostate, bile ducts, gall bladder, urinary bladder, urethra, or ureter. These results indicate that 11 beta HSD2 protein colocalizes with MR protein in the great majority of sodium-transporting epithelia involved in serous secretion and supports the proposal that 11 beta HSD2 is a pivotal determinant of mineralocorticoid receptor occupancy in man. Furthermore, our demonstration of colocalization in discrete areas of the lung suggests that mineralocorticoid agonists or antagonists, and/or inhibitors of 11 beta HSD2, may have unexpected applications in respiratory disease.

11Beta-hydroxysteroid dehydrogenase type II and mineralocorticoid receptor in human placenta.

In mineralocorticoid target organs, 11beta-hydroxysteroid dehydrogenase type II (11beta-HSD2) confers specificity on the mineralocorticoid receptor (MR) by converting biologically active glucocorticoids to inactive metabolites. Placental 11beta-HSD2 is also thought to protect the fetus from high levels of circulating maternal glucocorticoid. In this study, we examined the immunoreactivity of 11beta-HSD2 and MR in human placenta from 5 weeks gestation to full term using immunohistochemistry, 11beta-HSD2 messenger RNA (mRNA) expression using Northern blot analysis, and MR mRNA expression using RT-PCR analysis. Marked 11beta-HSD2 immunoreactivity was detected in placental syncytiotrophoblasts at all gestational stages. MR immunoreactivity was moderately detected in syncytiotrophoblasts, some cytotrophoblasts, and interstitial cells of the villous core. Marked mRNA expression of 11beta-HSD2 was detected in placenta by Northern analysis. RT-PCR analysis of MR in placental tissues showed an amplified product consistent in length with the primers selected. These results suggest that placental 11beta-HSD2 is involved in not only regulating the passage of maternal active glucocorticoids into the fetal circulation but also in regulation of maternal-fetal electrolyte and water transport in the placenta, as in other mineralocorticoid target organs.

17beta-hydroxysteroid dehydrogenase type 1 and 2 expression in the human fetus.

The present study investigates the expression patterns of 17beta-hydroxysteroid dehydrogenase (17betaHSD) isozymes in human fetal tissues to understand how estrogenic activity is regulated in the human fetus. Using enzyme assay, high 17betaHSD activity was detected in the placenta and liver, and low levels of 17betaHSD activity were also present in the gastrointestinal tract and kidney. After Northern blot analysis, we detected the messenger ribonucleic acid for 17betaHSD type 1 (17betaHSD1) only in the placenta, whereas that for 17betaHSD type 2 (17betaHSD2) was detected in the placenta, liver, gastrointestinal tract, and urinary tract at 20 gestational weeks. In RT-PCR analysis of the messenger ribonucleic acid transcripts, 17betaHSD 1 was predominantly expressed in the placenta, brain, heart, lung, and adrenal, whereas 17betaHSD2 expression was predominantly detected in the liver, gastrointestinal tract, and kidney. In addition, we detected 17betaHSD2 immunoreactive protein in surface epithelial cells of the stomach, absorptive epithelial cells of the small intestine and colon, hepatocytes of the liver, and interstitial cells surrounding the urinary tubules of the renal medulla. 17betaHSD2 in these tissues may be functioning in the prevention of in utero exposure of the fetus to excessive estradiol from the maternal circulation and amniotic fluids.

Aromatase and 17 beta-hydroxysteroid dehydrogenase type 1 in human breast carcinoma.

The in situ formation of estradiol plays an important role in the development and biological behavior of human breast cancer Aromatase and 17 beta-hydroxysteroid dehydrogenase type 1 (17 beta-HSD type 1) are two principal enzymes involved in in situ estradiol production. We evaluated the expression of aromatase and 17 beta-HSD type 1 by immunohistochemistry in 41 cases of invasive breast carcinoma (19 lobular and 22 ductal). We then examined the correlation among the expression of these enzymes, estrogen (ER) and progesterone (PR) receptor status, Ki67 labeling index of carcinoma cells, age, and the clinical stage of the patients. Marked aromatase immunoreactivity was observed in stromal cells around carcinomatous glands in 32 of 41 cases (78%), and 17 beta-HSD type 1 immunoreactivity was detected in carcinoma cells in 23 of 41 cases (56%). There was a significant correlation observed between expression of 17 beta-HSD type 1 and aromatase in invasive lobular carcinoma (P = 0.0119), but not in invasive ductal carcinoma. There was an inverse correlation between aromatase and ER status in invasive ductal carcinoma (P = 0.0213), but not in invasive lobular carcinoma. No other correlations were observed among 17 beta-HSD type 1, aromatase, PR, ER, clinical stage, age, and Ki67 labeling indexes. Aromatase and 17 beta-HSD are not always expressed simultaneously in human breast carcinoma, but their simultaneous expression is more frequent in invasive lobular carcinoma than invasive ductal carcinoma. Consequently, different mechanisms may be involved in the regulation of expression of these two enzymes in human breast carcinoma.