RESUMO
BACKGROUND: A significant number of patients with chronic obstructive pulmonary disease (COPD) exhibit skeletal muscle wasting and decreased capillary area formation, which correlate with increased mortality. AIM: To determine the molecular mechanisms mediating decreased capillary formation in COPD. METHODS: 24 patients with COPD and 12 matching controls were recruited. Patients with COPD were classified into mild, moderate and severe groups according to GOLD (global initiative for chronic obstructive lung disease) criteria. Biopsy specimens were obtained from the tibialis anterior muscle. Fibre typing and capillary formation, together with messenger RNA (mRNA) expression of hypoxia-inducible factors (HIF1alpha and HIF3alpha), vascular endothelial growth factors (VEGF-A, VEGF-B and VEGF-C isoforms) and von Hippel-Lindau (VHL) protein, were determined. VHL expression and localisation were further studied by immunohistochemistry. RESULTS: Skeletal muscle capillary formation decreased significantly with increasing disease severity. Compared with controls, a tendency to mRNA overexpression of HIF1alpha, HIF3alpha and VEGF isoforms was observed in mild and moderate COPD, which decreased at the severe stage. In contrast, skeletal muscle biopsy samples from patients with COPD exhibited significant overexpression of VHL at both the mRNA and protein level by immunohistochemistry. VHL protein was further determined to be localised to satellite cells. CONCLUSIONS: Overexpression of VHL was identified in the skeletal muscle of patients with COPD. Increased VHL activity may have a negative effect on transduction of the hypoxic signal and may contribute to decreased capillarisation in skeletal muscles of patients with COPD.
Assuntos
Músculo Esquelético/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo , Idoso , Antropometria , Proteínas Reguladoras de Apoptose , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Biópsia , Capilares/patologia , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/biossíntese , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/patologia , Reação em Cadeia da Polimerase/métodos , Doença Pulmonar Obstrutiva Crônica/patologia , RNA Mensageiro/genética , Proteínas Repressoras , Índice de Gravidade de Doença , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Regulação para Cima , Fatores de Crescimento do Endotélio Vascular/biossíntese , Fatores de Crescimento do Endotélio Vascular/genéticaRESUMO
BACKGROUND: Chromogranin (Cg) A is expressed in neuroendocrine and neuronal tissues. It is involved in the generation of secretory granules and is cleaved to form biologically active peptides. Targeted ablation of the Chga gene resulted in increased plasma catecholamines, high blood pressure, and decreased size and number of adrenal medullary chromaffin granules. The aim of this study was to determine whether Chga null mice display changes in the morphology and function of the endocrine pancreas. MATERIALS AND METHODS: Sections of pancreata from Chga-/-, Chga+/- and Chga+/+ mice, were immunostained with antibodies against synaptophysin, CgA, CgB, secretogranin II and the four major pancreatic islet hormones. Plasma was analysed for glucose, insulin, glucagon, somatostatin and pancreatic polypeptide (PP). RESULTS: CgA epitopes were undetectable in the islets of Chga-/- animals. CgB and secretogranin II epitopes were expressed in the islets of all animal groups albeit with decreased expression in Chga-/- islets. The islet number and size were decreased in the Chga-/- animals compared with Chga+/+. The proportion of insulin cells was decreased but somatostatin and PP cells were increased in Chga-/- mice compared to Chga+/+ mice. The nuclear size was decreased in insulin cells and increased in somatostatin cells in Chga-/- mice. Plasma insulin level was markedly decreased in the Chga-/- mice although fasting plasma glucose and glucagon were normal. CONCLUSION: Ablation of the Chga gene affected the islet volume, the composition, distribution and nuclear size of islet cell types and plasma insulin concentration. Our data indicate decreased insulin cell function and increased glucagon cell function. Our study shows that CgA exerts a significant influence on the endocrine pancreas with importance in maintaining islet volume, cellular composition and function.
Assuntos
Cromogranina A/fisiologia , Ilhotas Pancreáticas/crescimento & desenvolvimento , Ilhotas Pancreáticas/fisiologia , Animais , Contagem de Células , Tamanho Celular , Cromogranina A/deficiência , Cromogranina A/genética , Cromogranina B/metabolismo , Imuno-Histoquímica , Insulina/sangue , Ilhotas Pancreáticas/anatomia & histologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hormônios Pancreáticos/metabolismo , Secretogranina II/metabolismoRESUMO
Chromogranins and secretogranins belong to the granin family of proteins, which are expressed in neuroendocrine and nervous tissue. In earlier publications we have described the development of region-specific antibodies against CgA and CgB. In this study we describe antibodies to SgII and SgIII and their usefulness for immunohistochemical staining. Peptides homologous to defined parts of secretogranins II and III were selected and synthesized. Antibodies were raised and immunostainings were performed on normal human pancreas. The SgII 154-165 (N-terminal secretoneurin), SgII 172-186 (C-terminal secretoneurin) and SgIII antibodies immunostained all insulin-immunoreactive cells, most of the glucagon cells and some of the pancreatic polypeptide cells. The SgII 225-242 antibody immunostained only the insulin-containing cells. None of the antibodies immunostained the somatostatin cells. This study is the first observation of the expression of SgIII in human tissues, where we show expression of SgIII in three of the four major islet cell types in human pancreas.
Assuntos
Cromograninas/análise , Ilhotas Pancreáticas/química , Secretogranina II/análise , Adulto , Animais , Anticorpos/isolamento & purificação , Anticorpos/farmacologia , Cromograninas/imunologia , Glucagon/análise , Humanos , Imuno-Histoquímica , Insulina/análise , Polipeptídeo Pancreático/análise , Fragmentos de Peptídeos/análise , Ratos , Secretogranina II/imunologiaRESUMO
We studied the immunoreactivity of 12 different region-specific antibodies to the chromogranin A (CgA) molecule in the four major neuroendocrine cell types of the human pancreas by using double immunofluorescence techniques. The antibodies raised to the N-terminal and midportions of CgA showed, on the whole, stronger immunoreactivity than did the C-terminal antibodies, with a few exceptions. Often the immunoreactivity was stronger in glucagon cells. Insulin cells expressed immunoreactivity to all region-specific antibodies, but glucagon cells were nonreactive to two antibodies. Somatostatin cells reacted only with the C-terminal antibodies (amino acid sequences CgA 411-424), while PP cells were stained with four CgA region-specific antibodies between amino acid sequences 63-195. The cause of these differences may be that the CgA molecule is cleaved, partly masked, or partly translated from CgA mRNA. Microwave treatment improved only the staining with the CgA 361-372 antibodies, which indicates that masking is not the sole or entire cause. Our findings may indicate that the CgA molecule is cleaved in different ways in the various pancreatic endocrine cell types, giving rise to a variety of biologically functional fragments.
Assuntos
Cromograninas/metabolismo , Ilhotas Pancreáticas/metabolismo , Adulto , Especificidade de Anticorpos , Cromogranina A , Cromograninas/química , Cromograninas/imunologia , Glucagon/metabolismo , Humanos , Imuno-Histoquímica , Insulina/metabolismo , Ilhotas Pancreáticas/citologia , Polipeptídeo Pancreático/metabolismo , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Somatostatina/metabolismoRESUMO
Synaptic vesicle protein 2 (SV2) is a glycoprotein identified in the nervous system of several species, including man, but its occurrence in the human neuroendocrine (NE) cell system has not been investigated. By using a monoclonal antibody to SV2, immunoreactivities were demonstrated in NE cell types in human gastrointestinal tract, pancreas, anterior pituitary gland, thyroid, parathyroid, and adrenal medulla, and also in chief cells of gastric oxyntic mucosa. Immunoelectron microscopy of pancreatic islets revealed SV2 immunoreactivity in secretory granules. Comparison of SV2, synaptophysin, and chromogranin A immunoreactivity showed more SV2- and synaptophysin- than chromogranin A-immunoreactive cells in the antrum and pancreas. In the other gastrointestinal regions and in the other endocrine organs more SV2- than synaptophysin-immunoreactive cells were seen. More chromogranin A- than SV2-immunoreactive cells were observed in duodenum, colon, and parathyroid. Various NE tumors were examined and all contained SV2-immunoreactive cells. The staining patterns with the three markers agreed well, except in hindgut carcinoids, which showed strong SV2 immunoreactivity, weak synaptophysin but no chromogranin A immunostaining. In pituitary adenomas more cells were immunoreactive to SV2 than to the other two antibodies. In conclusion, SV2 is recognized as a further broad marker for NE cells and widens the arsenal of diagnostic tools for NE tumors. It is of special importance for identifying hindgut carcinoids.
Assuntos
Glicoproteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Sistemas Neurossecretores/metabolismo , Biomarcadores , Cromogranina A , Cromograninas/metabolismo , Neoplasias das Glândulas Endócrinas/metabolismo , Neoplasias das Glândulas Endócrinas/patologia , Humanos , Microscopia Eletrônica , Microscopia Imunoeletrônica , Neoplasias do Sistema Nervoso/metabolismo , Neoplasias do Sistema Nervoso/patologia , Sistemas Neurossecretores/patologia , Sistemas Neurossecretores/ultraestrutura , Valores de Referência , Sinaptofisina/metabolismoRESUMO
Knowledge concerning tissue-specific expression of the five somatostatin receptor subtypes is of great importance in understanding their physiological function. We developed rabbit polyclonal antibodies specific for each human somatostatin receptor subtype and report our results concerning the expression in normal endocrine pancreatic cells. The antibodies were produced by immunizing rabbits with fragments specific for the five cloned somatostatin receptor subtypes. Colocalization of these somatostatin receptors with the four major islet hormones--insulin, glucagon, somatostatin, and pancreatic polypeptide--was studied in normal human endocrine pancreatic cells, using double-immunofluorescence staining. High expression of somatostatin receptor subtypes 1, 3, and 4 was found in all endocrine pancreatic cells. Somatostatin receptor subtype 2 was frequently expressed in alpha and beta cells, whereas expression was low in pancreatic polypeptide cells and intermediate in delta cells. Somatostatin receptor subtype 5 was expressed in most beta and delta cells but almost absent in alpha and pancreatic polypeptide cells. There is a variability in the normal expression of somatostatin receptor subtypes among the different human endocrine pancreatic cells. Knowledge of this expression and the physiological function mediated by these receptors will be valuable in the future when considering treatment of endocrine disorders.
Assuntos
Ilhotas Pancreáticas/metabolismo , Receptores de Somatostatina/classificação , Receptores de Somatostatina/metabolismo , Animais , Especificidade de Anticorpos , Glucagon/metabolismo , Humanos , Imuno-Histoquímica , Insulina/metabolismo , Ilhotas Pancreáticas/citologia , Polipeptídeo Pancreático/metabolismo , Coelhos , Receptores de Somatostatina/imunologia , Somatostatina/metabolismo , Células Secretoras de Somatostatina/metabolismoRESUMO
Insulin-like growth factor II (IGF-II) appears to play an important role during fetal life in cell growth and differentiation in several organs, including the pancreas. In the present study we investigated the cellular localization of IGF-II in human fetal pancreas at 16, 18 and 22 embryonic weeks and compared it with adult pancreas. Single and double immunofluorescence methods were used to study co-localization of IGF-II with the four major islet hormones - insulin, glucagon, somatostatin, pancreatic polypeptide - and with islet amyloid polypeptide (IAPP). Distinct IGF-II immunoreactive (IR) cells were found in the endocrine, but not in the exocrine, pancreas. The intensity of IGF-II immunoreactivity was more pronounced in the fetal than in the adult pancreas. In fetal pancreas IGF-II immunoreactivity was observed in virtually all insulin-IR cells and in subsets of the glucagon, somatostatin and IAPP cells. In the adult pancreas, IGF-II immunoreactivity was found in insulin/IAPP cells only. Our results suggest a broader effect of IGF-II in fetal endocrine pancreatic cells than in the adult.
Assuntos
Fator de Crescimento Insulin-Like II/análise , Ilhotas Pancreáticas/química , Ilhotas Pancreáticas/embriologia , Adulto , Amiloide/análise , Feminino , Imunofluorescência , Glucagon/análise , Humanos , Insulina/análise , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Polipeptídeo Pancreático/análise , Gravidez , Segundo Trimestre da Gravidez , Somatostatina/análiseRESUMO
Glucose-induced insulin release is markedly decreased in the spontaneously diabetic Goto-Kakizaki (GK) rat pancreas. This defect was recently shown to be reversed by forskolin which markedly enhances cAMP generation in GK islets. These effects of forskolin were associated with overexpression of type-3 adenylyl cyclase (AC) mRNA due to the presence of two functional point mutations in the promoter region of AC3 gene in GK rat. Nine AC isoforms have been described, but their expression pattern in relation to the main pancreatic islet cell types, as well as their involvement in the diabetic state, is still unknown. Using antibodies raised against AC1-8, we have studied by double immunofluorescence the localisation of these AC isoforms in different endocrine cell types in both normal and diabetic GK rat pancreas. Our results demonstrated a clear immunoreaction (IR) to AC1-4 and 6 in normal and GK islet beta-cells, while a smaller number of ACs were expressed in alpha- and delta-cells. No AC-IR was observed in pancreatic polypeptide cells. Moreover, we have found an increased IR of the Ca2+-stimulated ACl, AC3 and AC8 in diabetic beta- and alpha-cells, compared with the corresponding IR in control pancreas. Most noticeable was the eliciting of a markedly enhanced AC8-IR in GK rat beta- and alpha-cells, in contrast to a barely discernible AC8-IR in corresponding normal cells. In conclusion, AC expression exhibits a complex pattern in the endocrine pancreas, with specific differences between the normal and diabetic state.
Assuntos
Adenilil Ciclases/química , Diabetes Mellitus Tipo 2/enzimologia , Pâncreas/enzimologia , Animais , Anticorpos , Especificidade de Anticorpos , Modelos Animais de Doenças , Glândulas Endócrinas/enzimologia , Glândulas Endócrinas/imunologia , Glândulas Endócrinas/patologia , Regulação da Expressão Gênica , Glucagon/metabolismo , Imuno-Histoquímica , Insulina/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/enzimologia , Ilhotas Pancreáticas/imunologia , Masculino , Camundongos , Pâncreas/patologia , Isoformas de Proteínas/imunologia , Ratos , Ratos Endogâmicos , Ratos Wistar , Somatostatina/metabolismoRESUMO
Thyroidectomy appears to reduce the serotonin content in the rat brain, whereas hyperthyroidism has the opposite effect. As it is not known whether the serotonin-producing cells of the gastrointestinal tract are influenced by these conditions, the effects of thyroparathyroidectomy and induced hyperthyroidism were studied experimentally, particularly as regards the serotonin- and gastrin-immunoreactive cells of the gastrointestinal tract. Immunocytochemical and quantification techniques were used to localize and determine the numbers of serotonin and gastrin cells. In thyroparathyroidectomized rats the intestine was significantly shorter and the mucosa thinner than in sham-operated and untreated controls, whereas the converse was found in the hyperthyroid rats. Following thyroparathyroidectomy, there were fewer gastrin-immunoreactive cells in antrum and the serotonin-immunoreactive cells were significantly less dense throughout the gastrointestinal tract. In hyperthyroid rats, gastrin-immunoreactive cells were more numerous, as were the serotonin-immunoreactive cells in the small intestine, whereas these cells were fewer in antrum and caecum. In conclusion, the thyroid gland exerts a significant influence on the gastrointestinal tract and on the serotonin-and gastrin-immunoreactive cells. The observed alterations may reflect a direct effect of the thyroid hormones, although indirect factors must also be considered.
Assuntos
Sistema Digestório/metabolismo , Células Secretoras de Gastrina/metabolismo , Hipertireoidismo/metabolismo , Paratireoidectomia , Serotonina/metabolismo , Tireoidectomia , Animais , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Distribuição Aleatória , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND/AIMS: Hypergastrinaemia has been reported in liver cirrhosis; meanwhile, it is unclear whether it is associated with an increase in gastrin cell function. The serum gastrin concentration and the number of gastrin cells in antral biopsies were studied in patients with alcoholic liver disease. METHODS: Immunocytochemical and quantification techniques were used to localize and determine the number of gastrin cells. RESULTS: Slight non-significantly higher serum gastrin values were observed in the alcoholic liver disease patients compared with controls, but the individual variation within the groups was considerable. The frequency of gastrin cells did not differ between groups. However, the size of the gastrin cell nuclei was larger in patients with liver disease than in controls, indicating increased cellular activity. CONCLUSIONS: Alcoholic liver disease, with a disturbed liver function, influences the gastrin cells. The observed alterations may reflect the effect of alcohol and/or malnutrition, or may be secondary to the influence of liver disease on other regulatory peptides.
Assuntos
Mucosa Gástrica/metabolismo , Gastrinas/sangue , Gastrinas/metabolismo , Hepatopatias Alcoólicas/sangue , Hepatopatias Alcoólicas/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Núcleo Celular/patologia , Mucosa Gástrica/patologia , Humanos , Imuno-Histoquímica , Hepatopatias Alcoólicas/patologia , Masculino , Pessoa de Meia-Idade , Antro Pilórico/metabolismo , Antro Pilórico/patologiaAssuntos
Cromograninas/metabolismo , Sistema Digestório/metabolismo , Sistemas Neurossecretores/metabolismo , Pâncreas/metabolismo , Anticorpos Monoclonais , Cromogranina A , Cromograninas/química , Cromograninas/imunologia , Sistema Digestório/citologia , Humanos , Imuno-Histoquímica , Sistemas Neurossecretores/citologia , Pâncreas/citologia , Frações Subcelulares/metabolismoRESUMO
OBJECTIVE AND DESIGN: Co-localization of the four major pancreatic hormones, and also of islet amyloid polypeptide (IAPP), peptide tyrosine tyrosine (PYY), secretin and neurotensin, has been studied in the endocrine pancreas of human fetuses at 16, 18 and 22 weeks of gestation. METHODS: Double and triple immunofluorescence stainings have been used. RESULTS: All three fetal pancreata contained cells that showed insulin, glucagon, somatostatin, pancreatic polypeptide (PP), IAPP, secretin and PYY immunoreactivity. Neurotensin cells were found in the youngest fetus and gastric inhibitory polypeptide (GIP) in the two older fetuses. Co-localization of two hormones occurred in most of the endocrine cell types in the three fetuses examined, but three hormones occurred in only a few cells and especially in the youngest fetus. Somatostatin cells were the only cell type which was largely monohormonal. Our findings showed that there are two different co-localization patterns: insulin was co-localized mainly with IAPP and glucagon, while secretin and PYY occurred together with glucagon and PP. CONCLUSIONS: These data are the first to describe secretin and neurotensin in the fetal pancreas. Two different co-localization patterns could be distinguished: insulin, IAPP and glucagon, and glucagon, secretin, PP and PYY.
Assuntos
Glucagon/metabolismo , Insulina/metabolismo , Pâncreas/embriologia , Polipeptídeo Pancreático/metabolismo , Somatostatina/metabolismo , Amiloide/imunologia , Amiloide/metabolismo , Feminino , Feto/imunologia , Feto/metabolismo , Imunofluorescência , Glucagon/imunologia , Humanos , Insulina/imunologia , Secreção de Insulina , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Neurotensina/imunologia , Neurotensina/metabolismo , Pâncreas/imunologia , Pâncreas/metabolismo , Polipeptídeo Pancreático/imunologia , Peptídeo YY/imunologia , Peptídeo YY/metabolismo , Gravidez , Secretina/imunologia , Secretina/metabolismo , Somatostatina/imunologiaRESUMO
Colocalisation of synaptophysin has been studied in different neuroendocrine cell types in histologically normal mucosa from human gastrointestinal tract (corpus, antrum, duodenum, ileum and colon) using double-immunofluorescence stainings. Numerous synaptophysin immunoreactive cells were seen in the antrum, while a smaller number were found in the intestinal tract. Synaptophysin immunoreactivity was strong in the antrum but weak in the intestine. In the intestinal colocalisation studies the synaptophysin immunoreactivity was enhanced by using the tyramide amplification method. Synaptophysin and chromogranin A were colocalised but the latter occurred mainly basally, whereas synaptophysin was found to occur diffusely throughout the cytoplasm. Synaptophysin immunoreactivity occurred in the serotonin cells throughout the gastrointestinal tract, and in the antral gastrin and somatostatin cells. In the intestinal tract only a small fraction of somatostatin, gastrin, cholecystokinin, enteroglucagon, enteroglucagon/ peptide tyrosine tyrosine displayed synaptophysin immunoreactivity. In the gastrointestinal tract (except the antrum), chromogranin A is a better general neuroendocrine marker than synaptophysin. The functional role of synaptophysin is unclear but it may be involved in the intracellular transport and release of hormones. Based on the distribution background of synaptophysin, it seems to be of greater importance in the antrum than in the intestinal tract as a whole.
Assuntos
Células Enteroendócrinas/química , Sinaptofisina/análise , Adulto , Animais , Cromograninas/análise , Hormônios/análise , Humanos , Coelhos , Células Tumorais CultivadasRESUMO
Co-localization of chromogranin (Cg) A, B, and C has been studied in different neuroendocrine cell types in histologically normal mucosa from human gastrointestinal tract (corpus, antrum, duodenum, ileum, and colon) using single-, double-, and triple-immunofluorescence stainings. Virtually all enterochromaffin (EC) cells contained CgA, and those in the luminal two thirds of the antral mucosa and villi of small intestine often also contained CgB. A few EC cells in the duodenal crypts contained CgC. Most gastrin cells harbored both CgB and CgA, although rather more CgB than CgA, but some gastrin cells contained all three types, i.e., also CgC. Some CCK cells also contained all three chromogranins. Enteroglucagon cells in the duodenal villi contained CgA and some CgB. CgA (but not B or C) was found in some secretin, GIP, enteroglucagon/peptide YY, and neurotensin cells. A few somatostatin cells contained CgA but neither CgB nor CgC. CgA and C were found mainly in the basal cell region, whereas CgB occurred more diffusely throughout the cytoplasm. This varying distribution suggests that not all secretory granules contain CgA, or that CgB may occur in a nongranular form. The varying composition of the different chromogranins may reflect their complex functional roles in the widespread neuroendocrine system.
Assuntos
Cromograninas/análise , Sistema Digestório/química , Hormônios Gastrointestinais/análise , Sistemas Neurossecretores/química , Proteínas , Colecistocinina/análise , Cromogranina A , Colo/química , Duodeno/química , Células Enterocromafins/química , Imunofluorescência , Gastrinas/análise , Peptídeos Semelhantes ao Glucagon/análise , Humanos , Íleo/química , Antro Pilórico/química , Serotonina/análise , Estômago/química , Distribuição TecidualRESUMO
The effect of hypophysectomy on the gastrointestinal tract was studied in the rat 8 wk after operation, particularly regarding the frequency and distribution of serotonin, somatostatin and gastrin-immunoreactive cells. Body weight, the length of the intestine and the thickness of the mucosa of the antrum and small intestine were all reduced in the hypophysectomised rats compared with sham-operated and untreated controls. In the hypophysectomised animals the serotonin-immunoreactive cells were fewer in the antrum and caecum, whereas they were more numerous in the proximal large intestine. There were fewer gastrin-immunoreactive cells in the antrum, while the somatostatin-immunoreactive cells were more numerous in the antrum and caecum. The significant influence of hypophysectomy on the gastrointestinal tract could be direct, but could also be associated with the marked effect of pituitary deficiency on endocrine cells, known to exert both trophic and antitrophic actions. However, it could also be an indirect effect on metabolism, resulting in lower food intake, other endocrine cell systems, and growth factors.
Assuntos
Mucosa Gástrica/metabolismo , Hipofisectomia/efeitos adversos , Mucosa Intestinal/metabolismo , Intestino Delgado , Serotonina/metabolismo , Animais , Ceco , Gastrinas/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Somatostatina/metabolismoRESUMO
BACKGROUND/AIMS: Genetically diabetic (db/db) mice are a model for non-insulin-dependent diabetes in humans. The gastrointestinal tracts in 12-week-old db/db and nondiabetic control (db/+) mice were studied with particular emphasis on the endocrine cells. METHODS: Immunocytochemical and quantification techniques were used to localize and determine the number of cells containing serotonin and various regulatory peptides. RESULTS: In the antrum, the gastrin- and serotonin-immunoreactive cells were increased in number. In the large intestine, the enteroglucagon and the peptide tyrosine-immunoreactive cells were increased in number, whereas there were fewer serotonin-immunoreactive cells. There were also fewer somatostatin-immunoreactive cells in most gastrointestinal regions. In diabetic mice, the intestine was longer and its mucosa thicker than in control mice. CONCLUSIONS: The results indicate that the genetic diabetic (db/db) condition exerts a significant influence on the gastrointestinal tract and on the endocrine cell systems studied. The observed alterations may reflect the effect of indirect factors rather than the diabetes per se.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Mucosa Gástrica/metabolismo , Hormônios Gastrointestinais/metabolismo , Mucosa Intestinal/metabolismo , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Mucosa Gástrica/patologia , Gastrinas/metabolismo , Peptídeos Semelhantes ao Glucagon/metabolismo , Imuno-Histoquímica , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Serotonina/metabolismo , Somatostatina/metabolismo , Tirosina/metabolismoRESUMO
Effects of 5 weeks streptozotocin treatment on the mouse gastrointestinal tract were studied with special emphasis on enterochromaffin (EC) cells. In the streptozotocin-treated animals the frequency of EC cells was reduced in the antral area and in the small intestine, but increased in the colon. The length of the intestinal tract and the mucosal thickness were increased in these animals. Possible mechanisms underlying these abnormalities of the EC cell system are discussed.
Assuntos
Sistema Cromafim/efeitos dos fármacos , Diabetes Mellitus Experimental/patologia , Sistema Digestório/efeitos dos fármacos , Células Enterocromafins/efeitos dos fármacos , Estreptozocina/toxicidade , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Contagem de Células/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Sistema Digestório/patologia , Células Enterocromafins/patologia , Mucosa Gástrica/efeitos dos fármacos , Glicosúria/induzido quimicamente , Técnicas Imunoenzimáticas , Mucosa Intestinal/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
The effects of gastroenteroanastomosis, antral exclusion and antral resection on the enterochromaffin (argentaffin) cell system in the rat alimentary tract were studied 6 weeks after the operation. When measured as cell density per mm3 mucosa, the number of enterochromaffin cells was decreased in most gastrointestinal regions following the three surgical procedures. In the antral exclusion group this decrease was most apparent in the caecum and large intestine, and in the animals with antral resection it was most pronounced in the proximal and middle regions of the small intestine. When expressed per segment mucosa, the enterochromaffin cells were even more reduced in number in all three experimental groups, as a result of mucosal atrophy in the entire gastrointestinal tract. The atrophy was most pronounced in animals with gastroenteroanastomosis, and least pronounced in those with antral exclusion. The underlying mechanisms of the effects on the enterochromaffin cell system under these experimental conditions are discussed.
Assuntos
Sistema Cromafim/fisiologia , Células Enterocromafins/fisiologia , Gastroenterostomia , Antro Pilórico/cirurgia , Animais , Contagem de Células , Mucosa Gástrica/citologia , Mucosa Intestinal/citologia , Masculino , Ratos , Ratos EndogâmicosRESUMO
On the basis of staining results in closely related semi-thin sections from rat antral mucosa immunostained with polyclonal serotonin antibodies and silver-stained for the argentaffin reaction, respectively, three different cell populations could be distinguished. One of these cell populations showed both serotonin immunoreactivity and an argentaffin reaction, a second one serotonin immunoreactivity alone, and a third one only an argentaffin reaction. These cell populations were studied electron microscopically in ultra-thin sections located between the stained semi-thin sections. The cell population displaying an agentaffin reaction and serotonin immunoreactivity showed secretory granules of the enterochromaffin cell type. A similar granular appearance was observed in cells which only exhibited an argentaffin reaction. Serotonin immunoreactivity in the absence of an argentaffin reaction was evident in some G (gastrin) cells, and in some D1 and possibly also some D (somatostatin) cells; but not all the endocrine cells of the non-enterochromaffin type displayed serotonin immunoreactivity. The significance of the different reactions in the three cell populations is discussed.
Assuntos
Sistema Cromafim/ultraestrutura , Glândulas Endócrinas/ultraestrutura , Células Enterocromafins/ultraestrutura , Mucosa Gástrica/ultraestrutura , Animais , Mucosa Gástrica/análise , Masculino , Microscopia Eletrônica , Ratos , Ratos EndogâmicosRESUMO
The staining characteristics of the enterochromaffin cell system in the human and rat gastrointestinal tract were studied with 3 histochemical procedures--the Masson method, formaldehyde-induced fluorescence (FIF), and immunocytochemical techniques using both monoclonal and polyclonal serotonin antisera. A simple modification of the Masson technique is described and compared with several other modifications of the same technique. The specificities of the 2 antisera were examined with regard to serotonin and other monoamines and their albumin conjugates, monoamine precursors and metabolites, and also to serotonin-related substances. In the intestine, with very few exceptions the same cells reacted positively with the 3 staining methods, but often serotonin immunoreactivity was observed in larger cytoplasmic areas than the other 2 staining reactions. In the antral mucosa, a cell population with the same staining characteristics as mentioned above was seen, but 2 further cell populations were identified--one displaying FIF-argentaffin reactions but no serotonin immunoreactivity, and the other showing the opposite characteristics. At immunostaining, a discrepancy in the staining results between the 2 antisera was noted--a larger number of antral serotonin immunoreactive cells being demonstrated with the polyclonal than with the monoclonal antiserum; this discrepancy disappeared when the polyclonal antiserum was pretreated with C-terminal tetragastrin. A minor discrepancy in the number of stained cells was still observed between the use of immunostaining with monoclonal or with tetragastrin-pretreated polyclonal antiserum, and the use of the FIF-argentaffin reactions. The reason for this discrepancy is unclear.