Chromogranin A-positive Cells Research Articles

Clinical presentation, diagnosis, pathogenesis and treatment options for lymphocytic colitis (Review)

Lymphocytic colitis (LC) is characterized by chronic or relapsing non-bloody watery diarrhea and a macroscopically normal colon. However, histopathological examination of colonic biopsy samples reveals an increased intraepithelial infiltration of lymphocytes (≥20/100 enterocytes), and increased inflammatory cells within the lamina propria, but with a normal mucosal architecture. The reported prevalence of LC varies from 14.2 to 45 per 100,000 individuals, while its reported incidence is between 0.6 and 16 per 100,000 individuals. LC has a high rate of spontaneous symptomatic remission and is not associated with an increased risk of colon cancer or inflammatory bowel disease. The diagnosis is based on the histopathological findings. The density of colonic chromogranin A-positive cells provides an effective diagnostic tool with high sensitivity and specificity in both the right and left colon. Gastrointestinal infections, drugs, and/or autoimmunity may trigger chronic colonic low-grade inflammation. Colonic nitric oxide, serotonin and peptide YY (PYY) cell densities are markedly increased in patients with LC. It has been hypothesized that the low-grade inflammation in LC through the endocrine-immune axis causes this increase. It has been postulated further that these abnormalities in the neuroendocrine system of the colon are responsible for the diarrhea observed in patients with LC. The benign course and rate of spontaneous remission of LC denotes that drugs with severe side-effects should be avoided if possible. The drug cost and drug coverage may also be limiting factors for some patients. These aspects should be taken into account when making decisions regarding treatment options.

Abstract 406: Characterizing the molecular features of the neuroendocrine phenotype in castration resistant prostate cancer.

Abstract Metastatic castration-resistant prostate cancer (CRPC) has a poor prognosis and remains a significant therapeutic challenge. Understanding the conversion from hormone sensitive to castration resistance may promote the development of more effective therapies. Recent findings suggest that neuroendocrine (NE) differentiation may be associated with the development of CRPC. Our objective was to characterize the NE phenotype in CRPC. Using specimens obtained at radical prostatectomy and rapid autopsy at the University of Washington, 2 sets of tissue microarrays were made from 50 radical prostatectomies and 155 metastatic sites from 50 autopsy patients who died from CRPC (with up to 4 metastatic sites from each patient). NE markers, including Chromogranin A (CHGA), Neuron specific enolase (NSE) and Synaptophysin (SYN), as well as androgen receptor (AR) and prostate specific antigen (PSA) were analyzed by immunohistochemistry (IHC). To characterize the molecular features of the NE phenotype in CRPC, 78 corresponding metastatic sites were also assessed by Agilent gene expression analysis. IHC revealed that only 2 of 50 primary prostate cancers had >10% CHGA positive cells whereas 7 of 50 primary prostate cancers 1-10% of cells expressed CHGA and all 50 were AR positive. By contrast, 29 of 50 CRPC autopsy patients had at least 1 CHGA+ metastasis; 53 of 155 metastatic sites had >10% CHGA positive cells (11 sites were AR negative), and 7 had 1-10% CHGA positive cells. Compared to primary prostate carcinomas, CRPC metastases had an increase in the frequency of CHGA+ expression (4% vs. 58%, p<0.001). Two other NE markers were also highly expressed by >10% of cells in each of the CRPC metastases. Of 155 CRPC metastases: 28 were positive for SYN and 47 were positive for NSE. Co-expression of CHGA and SYN was observed in 22 sites from 10 patients (10 sites did not express AR) and co-expression of CHGA, SYN and NSE was observed in 12 sites from 6 patients (6 sites did not express AR). PSA, a surrogate of AR activity, was absent in all NE CRPC tumors that did not express AR. All AR negative sites (12/155) expressed at least one NE marker. Gene expression data were generated from 78 laser captured metastases, which were grouped into 4 categories: 21 CHGA+ sites, 6 CHGA+, SYN+ and AR- sites, 5 CHGA+, SYN+ and AR+ sites, and 40 CHGA-, SYN-, NSE- and AR+ sites. This study is the first extensive analysis of the NE features of CRPC. Our data suggest that a) the NE phenotype (as defined by CHGA expression) is significantly more common in CRPC than in hormone sensitive primary disease, b) NE status from different sites in the same patient can be heterogeneous, and c) the NE phenotype is not necessarily associated with the loss of AR. These molecular studies suggest that evolution from hormone sensitive to castration resistant disease involves emergence of NE characteristics over time that may explain the behavior of true “androgen independent” disease. Citation Format: Xiaotun Zhang, Ilsa Coleman, Roger Coleman, Khanhthy Doan, Martine Roudier, Lisly Chéry, Jennifer Noteboom, Celestia Higano, Lawrence D. True, Paul H. Lange, Peter S. Nelson, Robert L. Vessella, Colm Morrissey. Characterizing the molecular features of the neuroendocrine phenotype in castration resistant prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 406. doi:10.1158/1538-7445.AM2013-406

Endocrine differentiation of rat enterocytes in long-term three-dimensional co-culture with intestinal myofibroblasts

The proliferation and differentiation of the small intestinal epithelium depends on the microenvironment surrounding the stem cells, such as intestinal subepithelial myofibroblasts. Although there have been many culture studies of intestinal epithelial–mesenchymal interaction, a culture which allows long-term observations has been difficult. This study investigated the influence of intestinal subepithelial myofibroblasts on the proliferation and differentiation of intestinal epithelial cells with a relatively long-term observation of 3 wk using a 3D co-culture system. Cultured rat intestinal subepithelial myofibroblasts, obtained from the duodenum, were embedded in collagen gel and cells from the rat intestinal epithelial cell line IEC-6 seeded onto it. Histologic sections of the cell-embedded gels were made and histochemical and immunohistochemical examinations were carried out in conjunction with expression analysis of the pancreatic duodenal homeobox 1 (pdx-1) transcription factor in IEC-6 cells. The IEC-6 cells showed increased proliferation and displayed characteristic endocrine features when co-cultured with rat intestinal subepithelial myofibroblasts, arranging themselves into multilayer structures and becoming cuboidal, with abundant cytoplasm and oval nuclei. Some IEC-6 cells were immunohistochemically positive for chromogranin A and glicentin. They also expressed the pdx-1 transcription factor at both the mRNA and protein levels. The number and percentage of chromogranin A-positive cells increased with culture time, whereas no increase was observed in cells cultured without rat intestinal subepithelial myofibroblasts. The present study using a long-term 3D co-culture model has obtained evidence of the participation of intestinal subepithelial myofibroblasts in enteroendocrine differentiation, supported by the expression of pdx-1 and glicentin production.

Migration and distribution of neural crest-derived cells in the human adrenal cortex at 9-16 weeks of gestation: an immunohistochemical study

Neural crest-derived cells are believed to migrate into the fetal adrenal cortex from the medially-located hilus. However, there appears to be a paucity of observations of the migration and distribution of medullary cells in humans. In sagittal as well as horizontal sections of human fetuses between 9 and 16 weeks of gestation, we identified chromaffin, ganglion and Schwann-like cells in the developing adrenal gland using immunohistochemistry. Cells showing tyrosine hydroxylase (TH) immunoreactivity (i.e., candidate ganglion cells) entered the fetal cortex mainly from the medial half of the adrenal, but the path of entry also included the ventral, dorsal and caudal aspects. These cells displayed linear arrangements, forming a connection between the peripheral and central areas of the gland. S100 protein-immunoreactive cells (i.e., Schwann-like cells) accompanied most (but not all) of the TH-positive cells. The distribution of chromogranin A-immunoreactive cells (i.e., chromaffin cells) was similar to and overlapped with that of TH-positive cells. Chromogranin A-positive cells were observed around the aorta as well as in the adrenal. The entry of neural crest-derived cells does not appear to be restricted to a hypothetical medial hilus, but occurs widely around the cortex, with or without the accompaniment of Schwann-like cells. These cells advance in lines through the fetal cortex in a cord-like arrangement without destruction of the cortical architecture. Some of the TH-positive cells very likely express chromogranin A before entry into the adrenal.

Distinct morphological and immunohistochemical features and different growth rates among four human neuroblastomas heterotransplanted into nude mice

To elucidate more precisely the biological characteristics of neuroblastomas, we examined four human neuroblastomas heterotransplanted into athymic nude mice NB-39 (undifferentiated type), NB-45 (poorly differentiated type with undifferentiated component), NB-52 (poorly differentiated type), and NB-726 (differentiating type) by electron microscopy, immunohistochemistry, and radioimmunoassay for the peptides in tumors. Ultrastructurally, NB-45, NB-52, and NB-726 contained more numerous and variously sized neurosecretory granules than did NB-39. Immunohistochemistry revealed neurofilament proteins, tyrosine hydroxylase, neuropeptide Y (NPY), and chromogranin A-positive cells in the four tumors in the following order of frequency: NB-726, NB-45, NB-52, and NB-39. NB-726, NB-45, and NB-52, but not NB-39, contained galanin-positive tumor cells. NB-45 and NB-726 harbored a few positive cells for calcitonin gene-related peptide. Furthermore, NB-726 exhibited positivity to leu-enkephalin, met-enkephalin, vasoactive intestinal peptide (VIP), and serotonin. Radioimmunoassay substantiated the results of immunohistochemistry, showing NPY in all tumors and either galanin or VIP in three tumors, excepting NB-39. Average doubling time of the tumor was as follows: 2 days in NB-39, 10 days in NB-45, 22 days in NB-52, and 45 days in NB-726. These results indicate that human neuroblastoma cells have different biological characteristics and reduced growth rate with differentiation in terms of ultrastructure and of peptide production abilities.

Conditionally immortalized colonic epithelial cell line from a Ptk6 null mouse that polarizes and differentiates in vitro

PTK6 is an intracellular src-related tyrosine kinase that regulates differentiation in the intestine, where knockout animals have increased proliferative activity and growth characteristics. To explore the phenotype further we attempted to establish epithelial cell lines from the intestinal mucosa. We mated Ptk6 null mice with a tsSV40 large T transgenic mouse (Immortomouse) to obtain null mice carrying the SV40 gene. Intestinal tissues from these mice were cultured. We established a Ptk6 null epithelial cell line from the colonic mucosa. Consistent with a role of Ptk6 in cell differentiation, these cells have the characteristics of a stable progenitor cell. In monolayer culture, the cells form domes in the monolayer when confluent. When cultured on Transwell filters, the cells polarize and form an electrically resistant barrier. Formation of tight junctions was confirmed by demonstrating expression of ZO1 and occludin at the apical junctions, whereas E-cadherin localized to the basolateral membrane. When cultured in collagen gel, the Ptk6 null cells form complex organoids, some of which resemble cups of cells. These organoids contain cells with differentiated phenotypes. Using immunohistochemistry and confocal microscopy we have been able to identify villin-positive (absorptive cells) and a small percentage of mucin-containing cells (goblet cells) and chromogranin A-positive cells (endocrine cells). This conditionally immortalized cell line represents an excellent cell culture model system for exploring the mechanisms of cell function and epithelial differentiation in the colonic mucosa.

Application of light microscopical and ultrastructural immunohistochemistry in the study of goblet cell carcinoid in the appendix

BackgroundGoblet cell carcinoids appear less frequently in the appendix than do other carcinoids. In the presented work a case with a goblet cell carcinoid of the appendix is described.MethodsRoutine histological and histochemical methods were employed, with a combination of histochemistry and immunohistochemistry on one section and light and electron microscopical immunohistochemisty on paraffin-embedded material, were applied to identify the type of the carcinoid and to reveal the fine structure of cell types in the tumour nests of the appendix.ResultsDuring the biopsy of a patient who had undergone appendectomy, an infiltration with clusters of goblet cells in the submucosa of the appendix was found. After a second operation of right-sided hemicolectomy, similar clusters of goblet cells were detected in the muscle layers of the caecum. After 18 months the patient died from cirrhosis and had not developed metastases or any recurrence. Immunohistochemically the serotonin-, somatostatin-, chromogranin A- and synaptophysin-positive endocrine cells were basally attached to mucin-secreting cells. The combined staining revealed simultaneously present endocrine cells (chromogranin-A-positive) and mucin-secreting cells (PAS- or alcian blue-positive). The ultrastructural immunohistochemistry showed that chromogranin A-positive cells had discoid and pleomorphic granules and were located in tumour nests or as single cells in the appendiceal wall.ConclusionThe combined histochemical and immunohistochemical procedure and the ultrastructural immunohistochemistry on archival material could contribute in clarifying the diagnosis of goblet cell carcinoid.

Chromogranin A-positive tumor cells in human esophageal squamous cell carcinomas

Gastrointestinal cancers have frequently shown neuroendocrine (NE) differentiation, but whether NE differentiation occurs in esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, tissue sections obtained from 43 patients with ESCC from a high-incidence area of Northern China were used for the assessing of NE differentiation by immunohistochemistry using antibody against chromogranin A (CGA). In addition, the malignant characteristics and proliferation capacity of CGA-positive cells were also examined by immunohistochemistry. The clinicopathological significance of these CGA-positive tumor cells in ESCC was assessed. Of 43 ESCC samples, CGAimmunoreactive tumor cells were detected in 10 cases (23.26%). However, the CGA-positive tumor cells were scattered at a very low number among non-immunoreactive tumor cells and were rarely constituted a major part of cancer cell nests. Only 4.65% (2/43) cases showed a high density (>10 cells but <1% of total tumor cell mass) of CGA-positive tumor cells. P53 immunoreactivity was frequently shown, while Ki67 was hard to detect in these CGApositive cells. In addition, no relationship between CGA positivity rate and clinicopathological parameters was found. Thus, we concluded that lowdensity CGA-positive tumor cells can be detected in ESCC, supporting the notion that heterogeneous NE differentiation also exists in tumors that lack neuroendocrine cells in their normal epithelial counterparts.

Small cell carcinoma with concomitant adenocarcinoma arising in a Barrett’s oesophagus: report of a case with a favourable behaviour

Most Barrett's oesophagus-associated cancers are adenocarcinomas which occur in a pure form. They are rarely combined with another type of malignancy, such as endocrine tumours. Within the endocrine spectrum, small cell carcinomas (SmCC) usually have a highly aggressive behaviour with a poor prognosis. We report a case of composite SmCC and adenocarcinoma in the setting of a Barrett's oesophagus, in a 54-year-old man. This tumour was identified on a surgical specimen after neoadjuvant treatment with radiotherapy and 5-FU-Cis-platin based chemotherapy. The SmCC component was positive for chromogranin A, synaptophysin, neural cell adhesion molecule and neuron-specific enolase and negative for high molecular weight cytokeratin. The adenocarcinoma component showed a converse phenotype. In our case, the origin of the SmCC component could be explained by the numerous chromogranin A-positive cells observed in the Barrett's oesophagus or by the potential progenitor cells that may be located in the submucosal oesophageal gland ducts and the Barrett's metaplasia. Our report is thus indicative of the high and totipotential risk of Barrett's oesophagus. Moreover, it is particular because of its favourable behaviour, with a 6-year disease-free survival, after neoadjuvant chemoradiation, surgery and postoperative chemotherapy.

Primary Malignant Hepatic Pheochromocytoma with Negative Adrenal Scintigraphy

A 60-year-old male patient with hypertension was referred to our hospital because of insufficient blood pressure control (190/98 mmHg) and to rule out secondary hypertension. A computed tomography scan revealed no adrenal tumor but a large liver mass (5 x 5 cm), and magnetic resonance imaging showed a high signal intensity lesion on the T2-weighted image. Twenty-four hour urinary excretion of catecholamine metabolites was markedly increased, although a 123I-metaiodobenzyl guanidine (MIBG) scintigram failed to show accumulation in the hepatic mass, and no difference was noted between the catecholamine concentration in the tumor-drainage vein and that obtained from the vein draining from the non-tumor area. Liver biopsy did show features compatible with pheochromocytoma (i.e., chromogranin A-positive cells). Transcatheter arterial embolization of the liver tumor was conducted and resulted in a marked (50%) decrease in the 24-h urine normetanephrine excretion. Several metastatic foci were noted in the spinal bone and transcatheter arterial embolization (TAE) was also conducted with successful results. Thus, we experienced a case of primary malignant hepatic pheochromocytoma with negative 123I-MIBG scanning.

Immunohistochemical expressions of cytokeratins, mucin core proteins, p53, and neuroendocrine cell markers in epithelial neoplasm of appendix

Epithelial neoplasms of appendix are infrequent, and their pathological features are not fully characterized. We collected 33 cases of appendiceal tumors and examined immunohistochemically the expression of cytokeratins (CK, CK7, and CK20), mucin core protein (MUC1, MUC2, MUC5AC, and MUC6), E-cadherin, chromogranin A, and p53 protein. Gene analysis of TP53 was also conducted on exons 5 to 8. Clinically, mucinous tumors were predominant in females. Immunohistochemically, all the tumors expressed CK20, whereas CK7 was positive in one third of the cases. Similarly, MUC2 was expressed in all the tumors, whereas MUC1 and MUC5AC were detected in about a half of the cases. Although chromogranin A-positive cells are generally sparse in normal appendix, they were more common in mucinous tumors than in nonmucinous tumors. Contrary to the previous data reported (Mod Pathol 2002;15:599-605), mucinous carcinoma exhibited a higher frequency of p53-positive cells (mean 29%) compared with mucinous adenoma (2.8%) (P < .001), whereas nonmucinous tumors showed high levels of p53-positive cells to similar extent (51%-67%) in both adenoma and carcinoma. The high expression of p53 protein coincided with the presence of mutations in multiple sites of TP53 gene in mucinous tumors. This is the first report that characterized the immunophenotypic profile of appendiceal epithelial neoplasms with an emphasis of a higher frequency of p53 positivity in mucinous carcinoma cases compared with mucinous adenoma in the appendix.

Interleukin-8 Regulates Expression of Reg Protein in Helicobacter pylori-Infected Gastric Mucosa

Chronic inflammation induced by Helicobacter pylori infection is closely associated with epithelial cell proliferation and apoptosis, which are related to cellular turnover in gastric mucosa. Reg protein is a regenerating gene product and a potent growth factor for gastric mucosal cells, however, little is known regarding its association with the pathogenesis of H. pylori infection. The aim of this study was to investigate Reg protein production and its regulation in H. pylori-associated gastritis. Gastric fundic biopsy samples were taken from patients with and without H. pylori infection. In vivo expression of Reg protein was examined by Western blotting and immunohistochemistry methods. The effects of interleukin (IL)-8 on Reg protein expression and transcriptional activation of the Reg gene in ECC10 cells were investigated by Western blotting and luciferase assays, respectively. Reg expression was found localized in the deeper part of gastric fundic glands and clearly shown in chromogranin A-positive cells in the gastric corpus. Semiquantitative immunohistochemistry and Western blotting results for Reg expression were significantly associated with polymorphonuclear neutrophil activity and chronic inflammation of gastric mucosa. IL-8 production in the gastric mucosa was significantly augmented by H. pylori infection, while IL-8 dose-dependently stimulated Reg protein production and Reg promoter activity in vitro in cultured ECC10 cells. The present study showed for the first time that Reg protein may be a potent stimulator of gastric epithelial cells in H. pylori-infected human gastric mucosa stimulated by IL-8. Further, our findings provide evidence of a novel link between Reg protein and H. pylori infection, which may help explain the molecular mechanisms underlying H. pylori-associated diseases, including gastric cancer.

ECL-cell derived gastric cancer in male cotton rats dosed with the H2-blocker loxtidine.

Spontaneously hypergastrinemic cotton rats (Sigmodon hispidus) develop tumors that have the phenotype of an adenocarcinoma but most likely originate from the enterochromaffin-like (ECL) cells. Among inbred animals approximately 50% of the females, but <1% of males develop spontaneous gastric carcinomas. Gastrin is the principle carcinogen in this model, as >4 months of hypergastrinemia results in carcinoma, but a gastrin receptor antagonist prevents carcinomas. Carcinomas can also be induced by partial corpectomy. In the present study, the insurmountable H2-receptor antagonist loxtidine (200 mg/kg/day) was given to male cotton rats for 6 months. The loxtidine-dosed animals developed hypergastrinemia, whereas control animals remained normogastrinemic. At termination, 4 of 5 cotton rats had cancer located to the oxyntic mucosa, whereas 1 animal had dysplasia. The gastric mucosa of all of the control animals was normal. In the dysplastic mucosa of loxtidine-dosed animals there was a marked increase in chromogranin A-positive cells, where numerous groups of cells also stained positive with the Sevier-Munger technique. In areas of high proliferation and cancer there were also histidine decarboxylase, chromogranin A, and Sevier-Munger-positive cells, altogether indicating an ECL cell origin of the tumors. This represents an interesting animal model where ECL cell-derived gastric cancer can be induced by pharmacological acid inhibition in 6 months.

An Extremely Rare Case of Adenoma Malignum with Large Cystic Tumor Which Resulted in Urinary Obstruction

Background. Adenoma malignum is a rare variant of uterine cervical adenocarcinoma. In this report, we present an extremely rare case of adenoma malignum with large cystic lesions (diameter of more than 10 cm) which elicited urinary obstruction.Case. A 46-year-old Japanese woman, gravida 2, para 2, visited her local doctor for urinary obstruction, and 950 ml of urine was catheterized. Since abdominal ultrasonography suggested ovarian cystic tumor, she was referred to our hospital. Vaginal examination and ultrasonography revealed a child-head-sized multilocular cystic tumor in the Douglas pouch. Abnormal massive discharge was not observed at the time of admission. During preoperative examination, massive mucinous discharge suddenly occurred without pain. The cystic tumor size shrank from ×10 cm to ×4.0 cm in maximum diameter. Emergent abdominal hysterectomy was performed. The operative findings revealed collapsed cystic lesions in the posterior wall of the uterine cervix. Microscopically, the multiple cysts in the cervix were composed of high columnar and slightly atypical monolayer cells similar to endocervical mucinous cells. Vaginal invasion was also partly observed. Most of the tumor cells were positive for carcinoembryonic antigen and HIK1083 in their cytoplasm, and scattered chromogranin A-positive endocrine cells were also found in tumor glands, corresponding to minimal deviation adenocarcinoma (adenoma malignum). These lesions were diagnosed as FIGO stage IIa. The patient is disease-free 2 years after primary surgery.Conclusion. In the present report, we describe an extremely rare case of adenoma malignum with large cystic lesions reaching a diameter of 12 cm which resulted in urinary obstruction.

Relationship between neuroendocrine features and prognostic parameters in human prostate adenocarcinoma

The biological behaviour of prostate cancer is highly variable and prediction by the commonly employed prognostic parameters is not sufficient. The concept of neuroendocrine (NE) differentiation in prostate adenocarcinoma has recently received increasing attention due to possible implications for prognosis and therapy. Core needle biopsies from 142 newly diagnosed patients were immunohistochemically examined for the coexistence of NE differentiation using an antibody against chromogranin A (CgA). Circulating CgA was available in 106 of these patients. NE differentiation was found in 64 (45.1%) tumors. Among them 29 (20.4%) had CgA positive cells scattered or focally distributed in less than 5% per mm3 of tumor tissues, 26 (18.3%) between 5% and 10% and 9 (6.4%) more than 10%, respectively. There was a significant correlation between the extent of NE features and either Gleason score (P < 0.01) or stage of disease. Circulating CgA but not PSA correlated with immunohistochemical CgA (P < 0.03) particularly in metastatic cases. These data support the concept that NE differentiation in human prostate cancer has a negative prognostic significance. Circulating CgA levels reflect immunohistochemical findings.

Localization of xenin-immunoreactive cells in the duodenal mucosa of humans and various mammals.

Xenin is a 25-amino-acid peptide extractable from mammalian tissue. This peptide is biologically active. It stimulates exocrine pancreatic secretion and intestinal motility and inhibits gastric secretion of acid and food intake. Xenin circulates in the human plasma after meals. In this study, the cellular origin of xenin in the gastro-entero-pancreatic system of humans, Rhesus monkeys, and dogs was investigated by immunohistochemistry and immunoelectron microscopy. Sequence-specific antibodies against xenin detected specific endocrine cells in the duodenal and jejunal mucosa of all three species. These xenin-immunoreactive cells were distinct from enterochromaffin, somatostatin, motilin, cholecystokinin, neurotensin, and secretin cells, and comprised 8.8% of the chromogranin A-positive cells in the dog duodenum and 4.6% of the chromogranin A-positive cells in human duodenum. In all three species, co-localization of xenin was found with a subpopulation of gastric inhibitory polypeptide (GIP)-immunoreactive cells. Immunoelectron microscopy in the canine duodenal mucosa demonstrated accumulation of gold particles in round, homogeneous, and osmiophilic secretory granules with a closely adhering membrane of 187 +/- 19 nm diameter (mean +/- SEM). This cell type was found to be identical to the previously described canine GIP cell. Immunocytochemical expression of the peptide xenin in a subpopulation of chromogranin A-positive cells as well as the localization of xenin immunoreactivity in ultrastructurally characterized secretory granules permitted the identification of a novel endocrine cell type as the cellular source of circulating xenin.

Immunocytochemical localization of the extracellular calcium-sensing receptor in normal and malignant human large intestinal mucosa.

We identified the parathyroid type Ca(2+)-sensing receptor (CaR) in normal human colon mucosa and in cancerous lesions at the mRNA and protein level. Polymerase chain reaction produced an amplification product from reverse-transcribed large intestinal RNA which corresponded in size and length to a 537-bp sequence from exon 7 of the CaR gene. With a specific antiserum against its extracellular domain, the CaR could be detected by immunostaining in normal human colon mucosa in cells preferentially located at the crypt base. The CaR protein was also expressed in tumors of the large bowel in all 20 patients examined. However, the great majority of CaR-positive cells in the adenocarcinomas inspected were confined to more differentiated areas exhibiting glandular-tubular structures. Poorly or undifferentiated regions were either devoid of specific immunoreactivity or contained only isolated CaR-positive cells. In the normal mucosa and in glandular-tubular structures of cancerous lesions, the CaR was exclusively expressed in chromogranin A-positive enteroendocrine cells and in only a small fraction of PCNA-positive cells.

G protein-coupled cholecystokinin-B/gastrin receptors are responsible for physiological cell growth of the stomach mucosa in vivo.

Many peptide hormone and neurotransmitter receptors belonging to the seven membrane-spanning G protein-coupled receptor family have been shown to transmit ligand-dependent mitogenic signals in vitro. However, the physiological roles of the mitogenic activity through G protein-coupled receptors in vivo remain to be elucidated. Here we have generated G protein-coupled cholecystokinin (CCK)-B/gastrin receptor deficient-mice by gene targeting. The homozygous mice showed a remarkable atrophy of the gastric mucosa macroscopically, even in the presence of severe hypergastrinemia. The atrophy was due to a decrease in parietal cells and chromogranin A-positive enterochromaffin-like cells expressing the H+,K(+)-ATPase and histidine decarboxylase genes, respectively. Oral administration of a proton pump inhibitor, omeprazole, which induced hypertrophy of the gastric mucosa with hypergastrinemia in wild-type littermates, did not eliminate the gastric atrophy of the homozygotes. These results clearly demonstrated that the G protein-coupled CCK-B/gastrin receptor is essential for the physiological as well as pathological proliferation of gastric mucosal cells in vivo.

Vascular endothelial growth factor (VEGF) expression in prostatic tumours and its relationship to neuroendocrine cells.

Vascular endothelial growth factor (VEGF) expression was examined by immunohistochemistry in 45 prostatic carcinoma specimens and ten benign prostatic tumours (BPH). The majority of carcinoma specimens exhibited cytoplasmic staining for VEGF and showed a trend of increasing expression with dedifferentiation (2p = 0.003). Immunoreactive VEGF was also seen in the prostatic carcinoma cell lines, the order of staining intensity was PC3 > DU145 > LNCaP. Intense granular cytoplasmic staining for VEGF was observed in neuroendocrine-like cells which were seen focally in many of the prostatic specimens. Consecutive sections were incubated with a chromogranin A antibody to confirm the neuroendocrine phenotype of these cells. A significant correlation (P < 0.0001) between the total number of intensely stained VEGF-positive cells and chromogranin A-positive cells was found. A subpopulation of neuroendocrine-like cells also showed intense immunoreactivity for transforming growth factor alpha (TGF-alpha). A correlation was observed (2p = 0.0092) between the intensity of VEGF and TGF-alpha immunostaining in carcinoma cells which were not of neuroendocrine differentiation. The presence of these two angiogenic factors may aid the neovascularisation of carcinomas and their increased expression in tumour-associated neuroendocrine cells may contribute to a more aggressive phenotype.

The pathology of the adrenal glands in sudden infant death syndrome (SIDS)

The sudden infant death syndrome (SIDS) is at present based on unknown pathogenetical mechanisms but in industrial nations is the most common cause of death in infancy after the perinatal period. Studies of a large number of adrenal glands in this syndrome have not been reported. Therefore, we evaluated 146 SIDS cases (85 males, 61 females, aged 14-465 days) and 24 control cases (17 males, 7 females, aged 18-623 days) by light microscopy, morphometry and immunocytochemistry (anti-chromogranin A and anti-S100 protein). Our data revealed a normal maturation of the adrenal glands in SIDS cases. Necroses, extensive hemorrhages or inflammation were not found. A focal lipid depletion of the zona fasciculata was seen in 92% of the adrenal glands of the SIDS and control cases. We found a siderosis (in 33% of the SIDS cases and 4% of the control cases) and calcium deposits (13% and 12% respectively) due to hyperemic involution of the fetal zone. The medulla, including the sustentacular cells (S 100 protein-positive cells) and chromaffin cells (chromogranin A-positive cells) was unchanged. Our results indicate that the few morphological alterations of the adrenal glands in SIDS cases are the effect of the underlying disease and not the cause of the sudden death.