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PubMed1994

Impact of familial amyloid associated polyneuropathy on duodenal endocrine cells.

Duodenal endocrine cells in 11 patients with familial amyloid associated polyneuropathy (FAP) were compared with those in 12 healthy volunteers by means of immunohistochemistry and morphometry. The total endocrine cell content, determined by the argyrophilic reaction and chromogranin A immunoreactivity, was significantly reduced in FAP patients compared with controls. There was a significant reduction in the serotonin, cholecystokinin/gastrin, and secretin immunoreactive cell content. A decreased cell content was also noted for somatostatin and gastric inhibitory polypeptide immunoreactive cells but this was not statistically significant. Amyloid deposits were noted in seven of the 11 biopsy specimens from FAP patients, but otherwise the duodenum was histologically normal in both groups. The reduction in endocrine cell content was not correlated with the degree of amyloid deposit in the duodenum. These findings indicate that patients with FAP have reduced intestinal endocrine cells. This does not seem to be related to amyloid deposits in the mucosa or to villous or crypt abnormalities. The observed changes in endocrine cells may contribute to the development of intestinal motility dysfunction and maldigestion in these patients.

Adult↗
PubMed2006

The zinc-finger factor Insm1 (IA-1) is essential for the development of pancreatic beta cells and intestinal endocrine cells.

The pancreatic and intestinal primordia contain epithelial progenitor cells that generate many cell types. During development, specific programs of gene expression restrict the developmental potential of such progenitors and promote their differentiation. The Insm1 (insulinoma-associated 1, IA-1) gene encodes a Zinc-finger factor that was discovered in an insulinoma cDNA library. We show that pancreatic and intestinal endocrine cells express Insm1 and require Insm1 for their development. In the pancreas of Insm1 mutant mice, endocrine precursors are formed, but only few insulin-positive beta cells are generated. Instead, endocrine precursor cells accumulate that express none of the pancreatic hormones. A similar change is observed in the development of intestine, where endocrine precursor cells are formed but do not differentiate correctly. A hallmark of endocrine cell differentiation is the accumulation of proteins that participate in secretion and vesicle transport, and we find many of the corresponding genes to be down-regulated in Insm1 mutant mice. Insm1 thus controls a gene expression program that comprises hormones and proteins of the secretory machinery. Our genetic analysis has revealed a key role of Insm1 in differentiation of pancreatic and intestinal endocrine cells.

Animals↗
PubMed1990

A survey of endocrine cells in the pancreas of the echidna (Tachyglossus aculeatus) with special reference to pancreatic motilin cells.

Pancreatic endocrine cells were examined in a primitive egg-laying mammal, the echidna, using immunohistochemistry. Immunoreactive endocrine cells were observed using antisera to insulin, glucagon, somatostatin, avian pancreatic polypeptide and bovine pancreatic polypeptide. In addition, motilin-immunoreactive cells were identified in both the endocrine and exocrine pancreas of pouch-young and adult echidnas using three types of motilin antisera. Since the motilin-immunoreactive cells did not cross-react with any other pancreatic hormones tested, they are identified as an independent endocrine cell type.

APUD Cells↗
PubMed1999

Gut endocrine cells in birds: an overview, with particular reference to the chemistry of gut peptides and the distribution, ontogeny, embryonic origin and differentiation of the endocrine cells.

This review deals with gut endocrine cells in birds. It focuses on both morphological and developmental aspects of these cells, which were included members of Pearse's APUD series. They comprise many cell types, which, in birds as in mammals, produce serotonin and a range of regulatory peptides. The chemical structure of most avian gut peptides has been established. These peptides and their functions are outlined here. The types and distribution of avian gut endocrine cells are detailed and compared with the situation in mammals. In birds, ultrastructural work has been limited to certain types of gut endocrine cell and not as widely applied as in mammals. However, immunocytochemistry has found widespread application in studies on birds: the hatching chick and also the adult chicken and certain other species such as the quail and duck have been studied. Gut endocrine cells showing immunoreactivity for the following peptides/serotonin have been identified: somatostatin, pancreatic polypeptide (PP), peptide YY, glucagon, secretin, vasoactive intestinal peptide, gastrin, cholecystokinin (CCK), neurotensin, motilin, gastrin-releasing peptide, substance P, enkephalin and serotonin. The colocalization of different peptides (including chromogranins) and of peptides and serotonin in the same gut endocrine cells is reviewed: notable amongst such associations are glucagon with PP and gastrin/CCK with neurotensin in the same cells. On morphological grounds cells have been identified as endocrine in avian gut from at least 9 days of incubation. Immunocytochemical studies show the majority of the various types first to appear between 12 to 14 days of incubation, with substantial numbers being recorded from 17 days onwards. Experimental studies on chicken and quail embryos have determined the embryonic origin of gut endocrine cells: evidence is unequivocal that such cells arise from the endoderm, not the neural crest, other ectoderm or the mesoderm. Studies on avian embryos have also contributed to our knowledge of mechanisms controlling the differentiation of gut endocrine cells: evidence shows that gut mesenchyme plays an important role in provoking (or inhibiting) the development of gut endocrine cells and there are indications that the endocrine cell pattern in gut is established early and that an axially-derived factor may be important in this process. The kinds of genetic mechanism possibly involved are mentioned but full elucidation of the processes concerned is awaited. A better understanding of the formation of endocrine tumours of the gut should result from the findings.

APUD Cells↗
PubMed1986

[Microscopic organization of epithelial endocrine cells of the gastrointestinal tract mucosa in lower vertebrates. I. Epithelial endocrine cells of the stomach of the common frog].

The quantity, histotopography and submicroscopic organization of endocrine cells in various mucosal epithelium sections of frog were studied using light and electron microscopy. It is shown that the majority of endocrine cells per square millimetre is located in the proximal part of the stomach. Eight types of endocrine cells depending on the submicroscopic structure of secretory granules are defined.

Animals↗
PubMed1985

Small cell lung cancer, endocrine cells of the fetal bronchus, and other neuroendocrine cells express the Leu-7 antigenic determinant present on natural killer cells.

Small cell lung cancer is distinguished from other lung cancer histologic types by possessing a variety of neuroendocrine properties. Anti-Leu-7 is a monoclonal antibody that recognizes a 110,000-dalton molecular weight glycoprotein initially described on natural killer cells and subsequently reported on a variety of normal and malignant neural and neuroendocrine cell types. We have found intense anti-Leu-7 binding to a large number of small cell lung cancers, while other lung cancer types were negative or showed only weak and focal binding. Other antigens expressed by natural killer cells, lymphocytes, and monocytes were never or less often expressed on small cell lung cancer cells. In addition, we report for the first time anti-Leu-7 binding by carcinoids, carotid body tumors, pheochromocytomas, endocrine cells of the fetal bronchus and the adult intestine, and select pancreatic islet cells. Anti-Leu-7 binding by small cell lung cancer is consistent with a derivation from pulmonary precursor cells, and anti-Leu-7 staining is clinically useful for the identification of human neuroendocrine tumors of the amine precursor uptake and decarboxylation ("APUD") type.

Antibodies, Monoclonal↗
PubMed1994

Pancreatic islet cell reaggregation systems: efficiency of cell reassociation and endocrine cell topography of rat islet-like aggregates.

Single cells isolated from rat islets of Langerhans were cultured under conditions that support reassociation into islet-like aggregates. Comparisons were made of enzymatic methods of islet dissociation, rotational or static culture conditions, and culture at basal or stimulatory glucose concentrations. Over a period of 4 days the aggregates progressed through three stages of organization: cell coalescence to cellular chains, rearrangement of chains into small spheroids, and growth of spheroids. The numerical yield of aggregates was optimum after islets were dissociated with dispase. Culture under rotation resulted in the production of more aggregates of significantly larger diameter than under static conditions. Medium glucose concentrations of 4 and 11 mM supported cell reassociation under rotator culture, but no aggregation occurred under static culture at the basal (4 mM) glucose level. Aggregates resulting from 4-day rotator culture exhibited endocrine cell distributions similar to intact islets. Islet aggregates released insulin in response to glucose, but nonaggregated cells, maintained in culture, did not. The present comparisons reveal significant variability in the cellular composition, rate of formation, and yield of aggregates, and suggest that the methodology for producing aggregates should be carefully considered in experimental design.

Animals↗
PubMed1986

[Microscopic organization of epithelial endocrine cells of the gastrointestinal tract mucosa in lower vertebrates. II. Epithelial endocrine cells of the duodenum of the common frog].

The endocrine epithelium cells of the frog duodenum mucosa were studied using light and electron microscopy. In the intestinal epithelium endocrine cells are distributed among enterocytes all over the surface of mucosa. The greatest quantity of them is observed in the intestinal part in the proximity of the stomach. Six types of endocrine cells are identified on the basis of their granular structure and size. Some differentiation in submicroscopic organization of endocrine cells depending on their functional condition is defined.

Animals↗
PubMed1987

Gamma interferon induces novel expression of Ia antigens by rat pancreatic islet endocrine cells.

Pancreatic endocrine cells normally express only Class I gene products of the major histocompatibility complex (MHC). Recently it has been shown that in both patients with recent onset type I diabetes and acutely diabetic BB rats, residual islet beta cells express Class II MHC antigens. In an attempt to define a potential inducer of this aberrant Class II antigen expression, we have investigated the effect of in vitro incubation of rat isolated pancreatic islets with the lymphokine gamma interferon (IFN-gamma) on MHC antigen expression. Our results demonstrate that in vitro exposure to IFN-gamma induces novel expression of Class II antigens on the surface of rat islet endocrine cells and increases the level of pre-existing Class I antigen expression.

Animals↗
PubMed2002

Exendin-4 differentiation of a human pancreatic duct cell line into endocrine cells: involvement of PDX-1 and HNF3beta transcription factors.

Exendin-4 (EX-4), a long acting agonist of GLP-1, induces an endocrine phenotype in Capan-1 cells. Under culture conditions which include serum, approximately 10% of the cells contain insulin and glucagon. When exposed to EX-4 (0.1 nM, up to 5 days), the number of cells containing insulin and glucagon increased to approximately 40%. Western blot analysis detected a progressive increase in protein levels of glucokinase and GLUT2 over 3 days of EX-4 treatment. We explored the sequence of activation of certain transcription factors known to be essential for the beta cell phenotype: PDX-1, Beta2/NeuroD, and hepatocyte nuclear factor 3beta (HNF3beta). Double immunostaining showed that PDX-1 coexisted with insulin and glucagon in EX-4-treated cells. Treatment caused an increase in PDX-1 protein levels by 24 h and induced its nuclear translocation. Beta2/NeuroD protein levels also increased progressively over 24 h. HNF3beta protein level increased twofold as early as 6 h after EX-4 treatment. EMSA results indicated that EX-4 caused a 12-fold increase in HNF3beta binding to PDX-1 promoter area II. Beta2/NeuroD protein levels progressively increased after 24 h treatment. Differentiation to insulin-producing cells was also seen when Capan-1 cells were transfected with pdx-1, with 80% of these cells expressing insulin 3 days after transfection. PDX-1 antisense totally inhibited such conversion. During the differentiation of duct cells to endocrine cells, cAMP levels (EX-4 is a ligand for the GLP-1, G-protein coupled receptor) and MAP kinase activity increased. Our results indicate that EX-4 activates adenylyl cyclase and MAP kinase which, in turn, may lead to activation of transcription factors necessary for an endocrine phenotype.

Cell Differentiation↗
PubMed2002

Chromaffin cells as models of endocrine cells and neurons.

Chromaffin cells have many functional similarities to amine- and peptide-producing endocrine cells throughout the body and to both peripheral and central neurons. The hypothesis of a shared, neural origin for chromaffin cells and most other endocrine cells is not tenable. However, chromaffin cells and their neoplastic counterparts, known as pheochromocytomas, are valuable models for studies of endocrine and neural properties. In this session, PC12 rat pheochromocytoma cells are used in two novel applications: to identify profiles of gene expression that may mediate cell death in neurodegenerative disorders and to study mechanisms for transduction of hypoxic signals. Recently described pheochromocytoma cell lines from neurofibromatosis knockout mice are shown to be novel models for signaling by the receptor tyrosine kinase ret, and purified enterochromaffin-like (ECL) cells are shown to offer new opportunities to study the shared and distinctive aspects of neuroendocrine function using a normal cell type.

APUD Cells↗
PubMed1998

Distribution of N-cadherin and NCAM in neurons and endocrine cells of the human embryonic and fetal gastroenteropancreatic system.

For the first time, the distribution of N-cadherin and neural cell adhesion molecule (NCAM) as well as some neuropeptides in nerve cells and endocrine cells of the human embryonic and fetal gastroenteropancreatic system has been detected in early stages (from the 6th postovulatory week onwards). Epithelial cells of the stomach and small intestine contained gastrin and somatostatin and the epithelium of the small intestine also bombesin-positive cells. Myenteric ganglionic cells showed both bombesin and VIP and were NCAM- and N-cadherin-positive at all ages studied. Some basally granulated epithelial cells of stomach, duodenum and the upper part of jejunum contained N-cadherin. The number of these cells increased from 6th to 10th postovulatory weeks. Nerve cells and the cytoplasm of individual epithelial cells of pancreatic ducts were immunoreactive for NCAM and N-cadherin. NCAM- and N-cadherin-positive cells also appeared in Langerhans islets (> 10 weeks), mainly in their peripheral part. NCAM- and N-cadherin-positive endocrine cells were less numerous than endocrine cells producing somatostatin, bombesin, and VIP, probably reflecting the features of embryonic/fetal histogenesis of Langerhans islets from epithelial endocrine cells of pancreatic ducts. NCAM and N-cadherin were localized on the surface of endocrine islets cells as well as in the cytoplasm of single islet cells. This suggests the involvement of both membrane and soluble forms of adhesion proteins in embryonic/fetal histogenesis of human pancreatic islets. The early occurrence of N-cadherin (6th postovulatory week) in enteroendocrine cells supports the existence of a common precursor. The expression of NCAM and N-cadherin in nerve cells and endocrine cells of the human fetal gastroenteropancreatic system may indicate the involvement of neuronal adhesion mechanisms in the development of neuro-endocrine complexes of fetal stomach, small intestine and pancreas.

Cadherins↗
PubMed1979

Electron microscopic radioautographic identification of the ECL cell as the histamine-synthesizing endocrine cell in the rat stomach.

Rat gastric oxyntic glands contain argyrophil "enterochromaffin-like" endocrine cells that synthesize and store histamine and also have APUD ability--they can take up exogenous L-5-hydroxytryptophan (5-HTP), can decarboxylate it to 5-hydroxytryptamine (5-HT, serotonin) by the enzyme DOPA-decarboxylase, and can store the amine. Previous cytochemical studies suggested that these cells correspond to both the ECL and A-like cells, the two predominant endocrine cells identified by electron microscopy (EM) in rat oxyntic glands. In a recent study, however, we demonstrated that the ECL but not the A-like cell exhibited APUD ability when rat gastric mucosa was incubated with H3-5-HTP and studied by EM radioautography. The purpose of the present study was to identify by EM radioautography the histamine-synthesizing endocrine cells in the rat stomach. Pieces of rat (male Sprague-Dawley) gastric mucosa were incubated in organ culture with L-H3-histidine (50 muCi, 1.8 x 10(-5) M) with and without inhibitors and were processed for LM and EM radioautography. H3-histidine labeled the ECL cells heavily but the A-like and other endocrine cells only lightly. The labeling of ECL cells was only modestly reduced by cycloheximide, an inhibitor of protein synthesis, whereas the labeling of A-like and other endocrine cells was almost abolished. In contrast, the labeling of ECL cells was markedly reduced by 4-bromo-3-hydroxybenzyloxyamine (NSD-1055), an inhibitor of histidine decarboxylase and DOPA decarboxylase, but was not appreciably affected by carbidopa, an inhibitor of only the DOPA decarboxylase. Incubations with H3-histamine (50 muCi, 0.9 x 10(-5) M) failed to label endocrine cells. Thus, this study demonstrates that the ECL but not the A-like cell is the histamine-synthesizing endocrine cell of the rat stomach.

APUD Cells↗
PubMed2005

Growth and functional maturation of beta-cells in implants of endocrine cells purified from prenatal porcine pancreas.

The development of islet cell transplantation as a cure for diabetes is limited by the shortage of human donor organs. Moreover, currently used grafts exhibit a marginal beta-cell mass with an apparently low capacity for beta-cell renewal and growth. Although duct-associated nonendocrine cells have often been suggested as a potential source for beta-cell production, recent work in mice has demonstrated the role of beta-cells in postnatal growth of the pancreatic beta-cell mass. The present study investigated whether the beta-cell mass can grow in implants that are virtually devoid of nonendocrine cells. Endocrine islet cells were purified from prenatal porcine pancreases (gestation >110 days) and implanted under the kidney capsule of nude mice. beta-Cells initially presented with signs of immaturity: small size, low insulin content, undetectable C-peptide release, and an inability to correct hyperglycemia. They exhibited a proliferative activity that was highest during posttransplant week 1 (2.6 and 5% bromodeoxyuridine [BrdU]-positive beta-cells 4 and 72 h posttransplant) and then decreased over 20 weeks to rates measured in the pancreas (0.2% BrdU-positive cells). beta-Cell proliferation in implants first compensated for beta-cell loss during posttransplant week 1 and then increased the beta-cell number fourfold between posttransplant weeks 1 and 20. Rates of alpha-cell proliferation were only shortly and moderately increased, which explained the shift in cellular composition of the implant (beta-cell 40 vs. 90% and alpha-cell 40 vs. 7% at the start and posttransplant week 20, respectively). beta-Cells progressively matured during the 20 weeks after transplantation, with a twofold increase in cell volume, a sixfold increase in cellular insulin content, plasma C-peptide levels of 1-2 ng/ml, and an ability to correct diabetes. They became structurally organized as homogenous clusters with their secretory vesicles polarized toward fenestrated capillaries. We concluded that the immature beta-cell phenotype provides grafts with a marked potential for beta-cell growth and differentiation and hence may have a potential role in curing diabetes. Cells with this phenotype can be isolated from prenatal organs; their presence in postnatal organs needs to be investigated.

Animals↗
PubMed1991

Expression of the neural cell adhesion molecule in endocrine cells of the ovary.

In the adult mammalian ovary morphogenesis and differentiation processes are under hormonal control and, thus, occur in a highly regulated way during the sexual cycle. Cell-cell interactions, such as cell adhesion and cell separation, are crucial during these events. Here we show that the ovarian endocrine cells, which are prototypes of steroid-producing cells, express neural cell adhesion molecules (NCAMs). The combined use of in situ hybridization histochemistry, immunocytochemistry at the light and electron microscope levels, S1 nuclease protection assays, and Western blotting revealed that in the ovary of the adult rat during the estrus cycle and pregnancy, NCAM mRNA and the 140-kDa isoform of this protein are expressed mainly in granulosa cells of growing preantral and antral follicles and in corpora lutea. Since the granulosa cells lining the forming antrum and the antral fluid were strongly immunoreactive, a role for NCAM in the formation of the follicular antrum is proposed. The expression of NCAM was also associated with luteal cells of the active corpus luteum, indicating a role for NCAM in the morphogenesis of this endocrine compartment. Moreover, thecal cells of large follicles and hypertrophic thecal cells of atretic follicles expressed NCAM, as did interstitial cells, which are derived from thecal cells of atretic follicles. We propose that the adhesion molecule, NCAM, is an important factor involved in the recognition and intercellular interaction of ovarian endocrine cells and, thus, participates in the regulation of the cyclic remodeling processes of the ovarian endocrine compartments.

Animals↗
PubMed1999

Human rectal endocrine cells and aging.

Endocrine cells of the human rectum were investigated by immunocytochemistry and quantified by computerized image analysis in three different age groups. The age intervals were 20-29, 40-49 and 60-69 years. No statistically significant differences were found between the age groups, regarding the numbers of all endocrine cell types investigated, namely peptide YY (PYY)-, pancreatic polypeptide (PP)-, enteroglucagon-, somatostatin- and serotonin-immunoreactive cells. Nor was there any difference regarding the cell secretory index. Nuclear volume was significantly greater in the 40-49 year olds than the other age groups. There was no statistically significant difference between females and males regarding numbers of the endocrine cell types investigated. It is concluded that age does not affect the endocrine cells of the human large intestine as it was earlier found in animal models of aging. It is imperative that caution should be taken when applying results obtained in animal models of aging in humans.

Adult↗