ECL-cell carcinoids and carcinoma in patients homozygous for an inactivating mutation in the gastric H(+) K(+) ATPase alpha subunit.

A family with a missense variant of the ATP4A gene encoding the alpha subunit of the gastric proton pump (H(+) K(+) ATPase) has recently been described. Homozygous siblings were hypergastrinemic (median gastrin 486 pM) and had gastric tumours diagnosed at a median age of 33 years. In the current histopathological study, we further characterized the tumours found in the gastric corpus. The tumours had the histological appearance of carcinoids (NET G1 or G2) and were immunoreactive for the general neuroendocrine markers chromogranin A (CgA) and synaptophysin as well as the ECL-cell markers vesicular monoamine transporter 2 (VMAT2) and histidine decarbozylase (HDC). One of the tumours consisted of a NET G2 component, but also had a component with glandular growth, which morphologically was classified as an intestinal type adenocarcinoma. Many glands of the adenocarcinoma contained a large proportion of cells positive for neuroendocrine markers, especially the small vesicle marker synaptophysin and the cytoplasmic enzyme HDC. In conclusion, patients homozygous for an inactivating ATP4A mutation develop gastric ECL-cell carcinoids in their 3rd or 4th decade. The adenocarcinoma may be classified as neuroendocrine with ECL-cell differentiation.

Histidine decarboxylase and urinary methylimidazoleacetic acid in gastric neuroendocrine cells and tumours.

AIM: To study histidine decarboxylase (HDC) expression in normal and neoplastic gastric neuroendocrine cells in relationship to the main histamine metabolite. METHODS: Control tissues from fundus (n = 3) and corpus (n = 3) mucosa of six patients undergoing operations for gastric adenocarcinoma, biopsy and/or gastric surgical specimens from 64 patients with primary gastric neuroendocrine tumours (GNETs), as well as metastases from 22 of these patients, were investigated using conventional immunohistochemistry and double immunofluorescence with commercial antibodies vs vesicular monoamine transporter 2 (VMAT-2), HDC and ghrelin. The urinary excretion of the main histamine metabolite methylimidazoleacetic acid (U-MeImAA) was determined using high-performance liquid chromatography in 27 of the 64 patients. RESULTS: In the gastric mucosa of the control tissues, co-localization studies identified neuroendocrine cells that showed immunoreactivity only to VMAT-2 and others with reactivity only to HDC. A third cell population co-expressed both antigens. There was no co-expression of HDC and ghrelin. Similar results were obtained in the foci of neuroendocrine cell hyperplasia associated with chronic atrophic gastritis type A and also in the tumours. The relative incidence of the three aforementioned markers varied in the tumours that were examined using conventional immunohistochemistry. All of these GNETs revealed both VMAT-2 and HDC immunoreactivity, and their metastases showed an immunohistochemical pattern and frequency similar to that of their primary tumours. In four patients, increased U-MeImAA excretion was detected, but only two of the patients exhibited related endocrine symptoms. CONCLUSION: Human enterochromaffin-like cells appear to partially co-express VMAT-2 and HDC. Co-expression of VMAT-2 and HDC might be required for increased histamine production in patients with GNETs.

[Plasmacytic skin infiltration in multiple myeloma]. / Myeloma multiplex kórlefolyása során megjelenô plazmasejtes bôrinfiltráció.

UNLABELLED: Authors present a case of a therapy-resistant multiple myeloma who developed plasmacytic skin infiltration in the course of the disease. AIM: To define characteristics of skin infiltrating plasma cells, which differentiate them from those cells residing in the bone marrow in order to contribute to a better understanding of the epidermoinvasion process. METHODS: Histidine decarboxylase is the only enzyme capable for histamine synthesis having significance in cell proliferation. Histidine decarboxylase was determined in skin samples and bone marrow slides by immunohistochemical procedures and in bone marrow cells using flow cytometry analysis. RESULTS: The histidine decarboxylase expression of plasma cells participating in skin invasion disappeared, while that of bone marrow plasma cells remained. CONCLUSIONS: Authors conclude that the histidine decarboxylase loss would serve as an evidence for the dedifferentiation of epidermoinvasive cells as being the result of fundamental changes in histamine metabolism. As extramedullary myeloma cells differ from those residing in the bone marrow, their therapeutical response might also be different.

The role of histamine in human mammary carcinogenesis: H3 and H4 receptors as potential therapeutic targets for breast cancer treatment.

There is increasing evidence that describes a histamine role in normal and cancer cell proliferation. To better understand the importance of histamine in breast cancer development, the expression of histamine H3 (H3R) and H4 (H4R) receptors and their association with proliferating cell nuclear antigen (PCNA), histidine decarboxylase (HDC) and histamine content were explored in mammary biopsies. Additionally, we investigated whether H3R and H4R were implicated in the biological responses triggered by histamine in MDA-MB-231 breast cancer cells. The expression levels of H3R, H4R, PCNA, HDC and histamine content were determined by immunohistochemistry in 40 benign and malignant lesions. MDA-MB-231 cells proliferation (clonogenic assay and BrdU incorporation) and cell cycle distribution (flow cytometry) were evaluated upon treatment with histamine, H3R and H4R agonists and antagonists. Apoptosis was determined by Annexin staining and TUNEL assay. Cell migration was assessed by transwell system. Results indicate that H3R was detected in 67% (10/15) of benign lesions and in almost all carcinomas (24/25), being the level of its expression significantly higher in carcinomas (p = 0.0016). The non-tumoral breast tissue surrounding carcinomas revealed a lower H3R expression compared to the tumor cells. Only 13% (2/15) of the benign lesions expressed H4R compared to 44% (11/25) of the carcinomas. Interestingly, H3R expression was correlated in carcinomas with the expression of HDC and PCNA (p < 0.0001), and also histamine content (p = 0.0229). Accordingly, histamine increased MDA-MB-231 cells proliferation and also migration via H3R. In contrast, activation of H4R inhibited proliferation and this effect was associated with an arrest in the G(0)/G(1) phase of the cell cycle and an induction of apoptosis. Present findings demonstrate the presence of H3R and H4R in human mammary tissue and suggest that H3R may be involved in the regulation of breast cancer growth and progression representing a novel molecular target for new therapeutic approach.

Expression of non-mast cell histidine decarboxylase in tumor-associated microvessels in human esophageal squamous cell carcinomas.

Histamine is produced by mast cells and many other types of cells. The role of histamine released from mast cells in promoting tumor angiogenesis has been intensively studied; however, the role of non-mast cell histamine in regulating tumor angiogenesis has been largely ignored. In this study, tissue specimen sections from 43 patients with esophageal squamous cell carcinoma (ESCC) and normal esophageal biopsies from 17 heath individuals obtained from a high incidence area of north China were used to assess changes in microvessel density (MVD) and non-mast cell L-histidine decarboxylase (HDC) (the only rate-limiting enzyme that catalyzes the formation of histamine from L-histidine) expression in the tumor microenvironment by immunohistochemistry (IHC). In addition, the cellular characterization of non-mast cell HDC-positive cells in microvessels was examined by double IHC combined with HDC/CD34 and HDC/PCNA antibodies. These IHC analyses revealed a significantly increased HDC-positive MVD in ESCC as compared with normal controls, which accounted for approximately 61% of CD34-labeled general MVD in ESCC. Furthermore, IHC in serial sections and double IHC showed that most of these HDC-positive cells were CD34-positive endothelial cells in microvessels with an increased proliferative capacity. Thus, our results suggest that non-mast cell histamine expressed in endothelial cells of microvessels could be an additional cellular source and might play a role in regulating angiogenesis in ESCC.

High gastrin cell activity and low ghrelin cell activity in high-anxiety Wistar Kyoto rats.

Ghrelin is produced by gastric A-like cells and released in response to food deprivation. Interestingly, psychological stress also raises circulating ghrelin levels. This study compared plasma ghrelin levels in Sprague-Dawley (SPD) rats and high-anxiety Wistar Kyoto (WKY) rats. The two strains were also compared with respect to plasma gastrin, a gastric hormone with a pre- and postprandial release pattern opposite to that of ghrelin, and to the activity of the gastrin-dependent, histamine-forming ECL cells in the gastric mucosa. The rats were killed after being freely fed or after an over-night fast. The stomachs were weighed and tissue samples were collected for histological and biochemical analysis. Plasma ghrelin and gastrin levels were determined by RIA. While fasted SPD rats had higher plasma ghrelin levels than fasted WKY rats (P < 0.001), plasma ghrelin did not differ between freely fed rats of the two strains. Gastrin levels were higher in fed WKY rats than in fed SPD rats (P < 0.001). Despite the higher plasma gastrin level, the oxyntic mucosal histidine decarboxylase (HDC) activity (a marker of ECL-cell activity) in fed rats and the mucosal thickness did not differ between the two strains. In a subsequent study, rats were subjected to water-avoidance stress for 60 min, causing plasma gastrin to increase in WKY rats (P < 0.001) but not in SPD rats. In conclusion, high-anxiety WKY rats had lower circulating ghrelin and higher gastrin than SPD rats in both the fasted and fed state, while the ECL-cell activity (HDC activity) was only moderately affected.

Involvement of MAP kinases in lipopolysaccharide-induced histamine production in RAW 264 cells.

Roles of mitogen-activated protein (MAP) kinases in lipopolysaccharide (LPS)-induced production of histamine in the mouse macrophage-like cell line RAW 264 were analyzed. Incubation of RAW 264 cells in the presence of LPS increased histamine levels in the conditioned medium in a concentration- and time-dependent manner. The levels of histidine decarboxylase (HDC) mRNA and the 74-kDa HDC protein were also increased at 4 to 8 h and 8 to 12 h, respectively. LPS elicited the phosphorylation of p44/42 MAP kinase, p38 MAP kinase, and c-Jun N-terminal kinase (JNK). The MAP kinase-Erk kinase 1 inhibitor U0126 (0.1-10 microM) suppressed the LPS-induced phosphorylation of p44/42 MAP kinase, and inhibited the LPS-induced production of histamine and expression of the HDC mRNA and 74-kDa HDC protein in a concentration-dependent manner. The JNK inhibitor SP600125 (3-30 microM) suppressed the LPS-induced phosphorylation of c-Jun, and inhibited the LPS-induced production of histamine and expression of the HDC mRNA and 74-kDa protein in a concentration-dependent manner. Combined treatment with U0126 (0.3 microM) and SP600125 (10 microM) inhibited the LPS-induced production of histamine additively. The p38 MAP kinase inhibitor SB203580 (0.1-10 microM) partially inhibited the LPS-induced production of histamine. These findings suggest that LPS increases histamine production in RAW 264 cells by inducing the expression of the 74-kDa HDC protein, and that the LPS-induced expression of HDC is up-regulated at the transcriptional level by MAP kinases, especially p44 MAP kinase and JNK.

Immunohistochemical detection of histidine decarboxylase in neoplastic mast cells in patients with systemic mastocytosis.

Synthesis of histamine in hematopoietic progenitor cells may be one of the earliest events in mastopoiesis. We therefore asked whether the key enzyme involved in histamine production, histidine decarboxylase (HDC), can be used as an immunohistochemical marker for the detection of immature neoplastic mast cells (MC) in patients with MC-proliferative disorders. To address this question, we examined bone marrow biopsy specimens in a cohort of 102 patients with mastocytosis using an antibody against HDC. Independent of the maturation stage of MC, the anti-HDC antibody produced clear diagnostic staining results in all patients with systemic MC disease examined including those with MC leukemia and MC sarcoma, in which MCs are particularly immature. In these patients, expression of HDC was reconfirmed at the messenger RNA level by reverse transcriptase polymerase chain reaction analyses performed with RNA of highly enriched CD117(+) MC. In summary, HDC is expressed in neoplastic MC in patients with systemic mastocytosis independent of the maturation stage of cells or the variant of disease. Histidine decarboxylase should therefore be considered as a new MC marker in the screen panel of antigens used to diagnose high-grade MC malignancies.

Dedifferentiation of enterochromaffin-like cells in gastric cancer of hypergastrinemic cotton rats.

The role of enterochromaffin-like (ECL) cells in gastric carcinogenesis is not fully understood. Spontaneous tumours developing in hypergastrinemic female cotton rats have an adenocarcinoma phenotype, but numerous cells in the dysplastic mucosa as well as in the carcinomas are positive for neuroendocrine markers. In the present study of female cotton rats with 2 and 8 months' hypergastrinemia, the oxyntic mucosa of the stomach was examined histologically and immunolabelled for histidine decarboxylase (HDC) and pancreastatin, and hyperplastic and neoplastic ECL cells were evaluated by electron microscopy. These animals developed hyperplasia of the oxyntic mucosa in general and of the ECL cells in particular after 2 months and dysplasia and carcinomas after 8 months. The immunoreactivity of the ECL cells in the oxyntic mucosa was increased at 2 months and declined at 8 months. These histological changes were associated with progressive loss of secretory vesicles and granules in ECL cells. We suggest that ECL cells in hypergastrinemic cotton rats dedifferentiate with time and that the gastric carcinomas may develop from ECL cells.

Concentration of histamine in serum and tissues of the primary ductal breast cancers in women.

The aim of this study was to evaluate the concentration of histamine (HA) and the activities of their enzymes, namely histidine decarboxylase (HDC) and diaminooxydase (DAO) in 95 women with ductal breast cancer and in healthy women. The control group comprised 60 women without any pathological changes in their breasts, in whom mammoplasties were performed. In women with breast cancer the concentration of HA in serum was significantly higher than in healthy controls (9.1+/-3.2 vs. 5.9+/-3.1 nmol/l; P<0.001). The concentration of HA was significantly higher in neoplasmatic tissues of women with breast cancers than in unchanged tissues of healthy subjects in the control group (14.2+/-5.1 vs. 6.3+/-9.1 nmol/g; P<0.001). HDC activity was significantly elevated in cancerous tissues of women with breast cancer relative to unchanged tissues of healthy subjects (54.7+/-17.1 vs. 39.3+/-26.9 pmol/min per mg; P<0.01). However, the activity of DAO was significantly lower (14.0+/-0.4 vs. 36.1+/-9.7 pmol/min per mg; P<0.001) in neoplasmatic tissues than in normal tissues of healthy women. The adjacent healthy tissue of cancer revealed higher concentrations of HA than were found in unchanged tissues of healthy subjects (6.3+/-9.1 vs. 7.5+/-5.4 pmol/min per mg), but this difference did not reach statistical significance. The activity of HDC did not show any significant difference between the healthy tissues adjacent to cancer foci of women with breast cancer and normal tissues obtained from healthy subjects (39.3+/-26.9 vs. 34.5+/-24.3 pmol/min per mg). However, the activity of DAO was markedly lower than in unchanged tissues of healthy women in the control group (36.1+/-9.7 vs. 14.4+/-10.9 pmol/min per mg; P<0.001). The concentration of HA in cancerous tissues was significantly higher than in adjacent healthy tissues (14.2+/-5.1 vs. 7.5+/-5.4 nmol/g; P<0.001). The activity of HDC was significantly higher in cancerous tissues than in adjacent healthy tissues (54.7+/-17.1 vs. 34.5+/-24.3 pmol/min per mg; P<0.001), but there was no difference in the activity of DAO (14.0+/-6.4 vs. 14.4+/-10.9 pmol/min per mg). The significant elevation of HA concentration in cancerous tissues of women with the ductal breast cancers is caused by the increased synthesis and decreased inactivation of HA.

Immunoreactivity of gastric ECL and A-like cells in fasted and fed rats and mice.

The oxyntic mucosa of rat and mouse stomach harbors histamine-producing ECL cells and ghrelin-producing A-like cells. The ECL cells are known to be active when the circulating gastrin levels are elevated in response to food intake. The A-like cells are the main source of circulating ghrelin. In response to starvation, the circulating ghrelin is elevated as a hunger signal. The aim of the present work was to study the correlation between the immunoreactivities and cellular activities of the ECL cells and A-like cells. Rats were either fed or fasted for 48 h and mice for 24 h. Immunohistochemical examination with antiserum against chromogranin A-derived fragment pancreastatin revealed both the ECL cells and the A-like cells without a difference between fasted and fed animals. Histamine was limited to the ECL cells with no significant difference between fasted and fed animals. Histidine decarboxylase (HDC) immunoreactivity occurred predominately in the ECL cells of the fed, but not fasted, animals in which the HDC enzymatic activity in the oxyntic mucosa was higher than in fasted animals. Ghrelin immunoreactivity was increased in terms of intensity, but not cell density in fasted animals. Thus, the immunoreactivities of ECL cells and A-like cells might be affected by starvation.

Analysis of histamine-producing cells at the late phase of allergic inflammation in rats.

To identify histamine-producing cells at the late phase of allergic inflammation, the expression of L-histidine decarboxylase (HDC) was examined in the infiltrating leucocytes in the inflammatory locus. HDC activity and HDC mRNA levels in the infiltrating leucocytes in the pouch fluid of the immunized rats (that were injected with the antigen solution into the air pouch) were increased compared with those in the infiltrating leucocytes of the non-immunized rats. When infiltrating leucocytes collected 8 hr after antigen injection were cultured, histamine production by the cells from the immunized rats was higher than that from the non-immunized rats. In situ hybridization of HDC mRNA revealed that almost all the infiltrating leucocytes of the immunized rats, 4 hr after injection of the antigen, expressed HDC mRNA with high intensity, while those of the non-immunized rats showed only a weak intensity of HDC mRNA. In the immunized rats, approximately 90% of leucocytes infiltrating in the pouch fluid at 4 hr were neutrophils and 8% were monocytes/macrophages. Neither mast cells nor basophils were detected in the infiltrating leucocytes. When rat peritoneal neutrophils were incubated in the presence of 12-O-tetradecanoylphorbol 13-acetate, histamine production was significantly increased. These findings suggest that the leucocytes, mainly neutrophils, infiltrating at the inflammatory locus are responsible for histamine production at the late phase of allergic inflammation.

Granulocyte-macrophage colony-stimulating factor enhances interleukin-1beta stimulated histamine release in the preovulatory rat ovary.

The existence of immune cells including macrophages and mast cells in rat ovary implies that various cytokines from these cells may play a role in ovarian functions. The aim of the present study was to investigate whether granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-1beta are capable of stimulating histamine release and steroidogenesis in rat ovary, and to determine the sites of histamine production in the ovary. Histamine release from preovulatory ovarian tissues was stimulated in a dose-dependent manner at 3-30 ng/ml of GM-CSF in the presence of interleukin-1beta (10 ng/ml). However, treatment with GM-CSF and interleukin-1beta did not cause any significant change in the levels of ovarian steroids. Intense staining of histidine decarboxylase in the ovary was immunohistochemically detected in large granular cells on the morning of the pro-oestrus day. These results indicate that GM-CSF may be involved in the regulation of ovarian histamine secretion in mast cells partially by enhancing interleukin-1beta-induced histamine release in the process of ovulation.

Neuroendocrine (ECL cell) differentiation of spontaneous gastric carcinomas of cotton rats (Sigmodon hispidus).

BACKGROUND AND PURPOSE: Female inbred cotton rats develop adenocarcinomas in the oxyntic mucosa. Since a female preponderance is typical for enterochromaffin-like (ECL) cell tumors, we examined such tumors for ECL cells. Gastrin plays a decisive role in ECL cell tumorigenesis, so blood gastrin concentration and gastric mucosal pH were measured. METHODS: The stomachs from six female cotton rats (6 to 8 months old) were studied histologically, and at euthanasia, gastric mucosal pH was determined. Euthanasia was performed on 15 other female cotton rats of similar age for determination of blood gastrin values by radioimmunoassay (RIA) and gastric mucosal pH. Rats were classified macroscopically to have normal or thick oxyntic mucosa, with or without tumor. RESULTS: Among the six cotton rats studied histologically, two 6-month-old rats had normal and two others had thick gastric mucosa, whereas two 8-month-old rats had thick mucosa with tumors. The ECL cells were markedly hyperplastic in all rats with thick mucosa, and ECL cells were found in the neoplastic parenchyma. All cotton rats with normal-appearing gastric mucosa had pH <2.5, whereas 14 rats with thick mucosa had pH >3.1 and hypergastrinemia. CONCLUSIONS: Gastrin may play a major role in ECL cell hyperplasia and, perhaps, in adenocarcinoma genesis.

[A method for the assay of histidine decarboxylase activity].

The histamine-forming enzyme histidine decarboxylase (HDC) is induced in various tissues of mice in response to various physiological or inflammatory stimuli including stress, physical exercise, proinflammatory cytokines and hematopoietic cytokines. The induction of HDC also occurs in mast cell-deficient mice. The newly formed histamine produced through the induction of HDC diffuses away from its site of formation without being stored. Therefore, in addition to the release of histamine from mast cells or basophils, the induction of HDC is an important alternative mechanism for supplying histamine. Studies on the newly formed histamine may clarify new physiological or pathological roles of histamine. Here, we introduce a method that we devised for the simultaneous assay of HDC activity of many samples taken from mice. This method is based on (i) a simple method for the preparation of histamine-free enzyme solutions and (ii) a simple manual method for the separation of histamine formed in reaction mixtures containing HDC.

Localization of the histamine H2 receptor and gene transcripts in rat stomach: back to parietal cells.

In contrast with many physiological studies suggesting that histamine H2 receptors are present on acid-secreting parietal cells of the gastric epithelium, it was recently shown that immune cells in the lamina propria are the only cells expressing H2-receptor mRNAs (Mezey and Palkovits, Science, 1992, 258, 1662-1665). We have reinvestigated the cellular localization of H2 receptors in the rat stomach by visualizing both the H2 receptor mRNA and the H2-receptor protein itself. In situ hybridization histochemistry performed with an antisense riboprobe for the rat H2 receptor, and autoradiographic distribution of 125I-aminopotentidine binding sites, a highly selective H2-receptor ligand, did not show any labeling of the lamina propria. Signals were clearly and solely detected in the gastric epithelium, the strongest being observed in the upper part of the glands where the H2 receptor gene transcripts were only detected within parietal cells. In situ hybridization performed with an antisense riboprobe for L-histidine decarboxylase mRNA confirmed the basal localization of the histamine-synthetizing cells in the rat gastric gland, at some distance from parietal histamine-sensitive cells.

Marked increase in fundic mucosal histidine decarboxylase activity in a patient with H+,K(+)-ATPase antibody-positive autoimmune gastritis.

A 63-year-old woman was diagnosed as autoimmune gastritis by the presence of serum antibody against alpha-subunit of gastric H+,K(+)-ATPase. The patient did not have pernicious anemia, but showed achlorhydria, marked hypergastrinemia, enterochromaffin-like cell hyperplasia and an extremely high histidine decarboxylase activity in the gastric fundic mucosa. Intragastric acidification by infusion of hydrochloric acid via a nasogastric tube induced a transient reduction of serum gastrin level and fundic mucosal histidine decarboxylase activity. A marked increase in fundic mucosal histidine decarboxylase activity as well as hypergastrinemia appears to be the pathophysiologic response to achlorhydria caused by autoimmunity against gastric H+,K(+)-ATPase.

Effect of lipopolysaccharides on histamine synthesis by hematopoietic cells.

We show herein that lipopolysaccharides (LPS), in vitro, synergize with GM-CSF to increase histamine synthesis by murine bone marrow cells. LPS has no effect on its own and does not potentiate histamine synthesis promoted by IL-3, the only other cytokine sharing this biological activity with GM-CSF. Despite the fact that GM-CSF and LPS synergistically increase PGE2 levels, the potentiating effect of LPS does not require PGE2 that have been previously shown to enhance GM-CSF-induced histamine synthesis. We provide evidence that this effect of LPS on histamine production by bone marrow cells is mediated by the intracellular cAMP transduction signal. In addition, LPS and cAMP enhance GM-CSF-induced histidine decarboxylase activity, showing that both substances act on histamine synthesis. Contrary to in vitro results, LPS injection into mice induces an increase in both intracellular histamine and HDC activity in bone marrow cells. Our results support the conclusion that this effect is mediated by GM-CSF. In conclusion, LPS appears to be a powerful HDC inducer in hematopoietic organs because of its ability, on one hand, to induce circulating GM-CSF and, on the other hand, to potentiate GM-CSF induction of HDC.