Somatostatin-immunoreactive Cells Research Articles

Anatomical, histochemical, and immunohistochemical observations on the gastrointestinal tract of Gallinula chloropus (Aves: Rallidae)

BackgroundGallinula chloropus (Linnaeus, 1758) is a wild aquatic omnivorous bird characterized by a marked resistance to harsh environmental conditions and a worldwide distribution. In this study, anatomical, morphometrical, histochemical, and immunohistochemical techniques were employed to study the structure of the gastrointestinal tract of Gallinula chloropus.ResultsThe esophagus appeared tubular with no distinct crop. Both superficial (SPG) and deep (DPG) proventricular glands were present. The DPG filled about two-thirds of the total wall thickness. Histochemically, the mucosubstances revealed mixed alcian blue-PAS positive reactions. They were mainly localized in the acini of the esophageal glands and SPG, gastric surface epithelium, duct system of DPG, and intestinal goblet cells. The highest number of goblet cells per every 1 mm2 of the intestinal mucosa was seen within the ileum and rectum, 2555 ± 468 and 2607 ± 653 respectively. Notably, glucagon immunoreactive (IR) cells were abundant in the mucosa of the small and large intestines and the proventriculus, while somatostatin IR cells were concentrated within the acini of the DPG. IR cells for the mitosis marker phospho-histone H3 (PHH3) were highest within the entire intestinal crypts and mucosa-associated lymphoid tissues (MALT). In contrast, cells IR for the apoptosis marker C.CASP3 were remarkable in epithelial cells at the tips of intestinal villi and in MALT, reflecting the dynamic nature of the latter mentioned structures.ConclusionsThe findings of the present study advance our knowledge of the gross and microscopic anatomy of the gastrointestinal tract in wild birds and could help to enhance the productivity of Aves via improving gut health.

Changes in colonic enteroendocrine cells of patients with irritable bowel syndrome following fecal microbiota transplantation

Objectives The aim was to investigate the effect of fecal microbiota transplantation (FMT) on colonic enteroendocrine cells densities in patients with irritable bowel syndrome (IBS). Materials and methods This study is connected to the REFIT study, a double-blinded placebo-controlled trial to investigate using FMT for IBS treatment. Eighty-three subjects received either donor-FMT or placebo FMT (own feces) by colonoscope to cecum. Biopsies were obtained from sigmoid colon. Ten responders and ten non-responders consented to new biopsy one-year after FMT. Sixteen patients received donor-FMT and four received placebo FMT. Biopsies were immunostained for all of the colonic enteroendocrine cells and were quantified using computerized image analysis. Allocation sequence was revealed after obtaining re-biopsies and cells quantification. Results Scores for IBS-SSS (mean ± SEM) of responders (eight of 10 patients who received donor FMT) and non-responders changed from baseline to one year after FMT (297 ± 11 and 81 ± 16, p < .0001, and 270 ± 17 and 291 ± 16, p = .15, respectively). Using paired t-test to compare enteroendocrine cells densities one-year after FMT to baseline showed significant increase only in somatostatin immunoreactive cells density in the total IBS responders group (p = .023) and who received donor-FMT (p = .038). The densities of peptide YY and enteroglucagon immunoreactive cells increased significantly (p = .04 and .035, respectively) in donor-FMT recipients. No significant changes were noted in placebo FMT or nonresponders subgroups. Conclusion This study shows that colonic enteroendocrine cells densities significantly change in responders group that received donor-FMT. The mechanisms for the cross talks between gut microbiota and colonic enteroendocrine cells remain to be investigated.

The Organization of Somatostatin-Immunoreactive Cells in the Visual Cortex of the Gerbil.

Somatostatin (SST) is widely expressed in the brain and plays various, vital roles involved in neuromodulation. The purpose of this study is to characterize the organization of SST neurons in the Mongolian gerbil visual cortex (VC) using immunocytochemistry, quantitative analysis, and confocal microscopy. As a diurnal animal, the Mongolian gerbil provides us with a different perspective to other commonly used nocturnal rodent models. In this study, SST neurons were located in all layers of the VC except in layer I; they were most common in layer V. Most SST neurons were multipolar round/oval or stellate cells. No pyramidal neurons were found. Moreover, 2-color immunofluorescence revealed that only 33.50%, 24.05%, 16.73%, 0%, and 64.57% of SST neurons contained gamma-aminobutyric acid, calbindin-D28K, calretinin, parvalbumin, and calcium/calmodulin-dependent protein kinase II, respectively. In contrast, neuropeptide Y and nitric oxide synthase were abundantly expressed, with 80.07% and 75.41% in SST neurons, respectively. Our immunocytochemical analyses of SST with D1 and D2 dopamine receptors and choline acetyltransferase, α7 and β2 nicotinic acetylcholine receptors suggest that dopaminergic and cholinergic fibers contact some SST neurons. The results showed some distinguishable features of SST neurons and provided some insight into their afferent circuitry in the gerbil VC. These findings may support future studies investigating the role of SST neurons in visual processing.

Immunohistochemical study on the expression of biologically active substances in the endocrine pancreas of the European bison.

Previous morphological studies of mammalian pancreatic islets have been performed mainly in domestic and laboratory animals. Therefore, the present immunohistochemical investigation was conducted in a wild species, the European bison, using antibodies against glucagon-like peptide-1 (GLP1), glucagon, insulin and somatostatin. Morphological analyses revealed that the mean area of the endocrine pancreas constituted 2.1±0.1% of the whole area of the pancreas, while the mean area of a single pancreatic islet was 13301.5±686.5 µm2. Glucagon-immunoreac- tive cells accounted for 22.4±1.1% and occupied 19.4±0.4% of the average islet area. As many as 14.3±1.4% of pancreatic islet cells were shown to express GLP1, which constituted 12.6±0.8% of the mean area of the islet. Insulin expression was confirmed in 67.6±0.7% of pancreatic islet cells, which represented 62.3±4.9% of the mean total area of the pancreatic islet. As many as 8.5±1.3% of cells stained for somatostatin. The somatostatin-immunoreactive cell area was 4.9±0.3% of the mean pancreatic islet area. In summary, we have determined in detail for the first time the morphometry and islet composition of the European bison pancreas. The distri- bution patterns of immunoreactivities to the substances studied in the European bison show many similarities to those described in other ruminant species.

Morphological Responses of the Small Intestine of Broiler Chicks to Dietary Supplementation With a Probiotic, Acidifiers, and Their Combination

SUMMARY This study was conducted to investigate the effects of dietary supplementation of a probiotic (Bacillus subtilis), acidifiers, and their combination on the mucosa of the broiler small intestine. A total of 220 straight run 1-day-old broiler chicks (Ross 308) were distributed into 4 experimental treatments with 5 replicates per treatment as a 2 × 2 factorial arrangement. The factors were probiotic and a blend of acidifiers with 2 levels: 0.0% and 0.05% for probiotic, and 0.0% and 0.2% for acidifiers. On day 42, tissue samples from the duodenum, jejunum, and ileum of 5 birds from each group were collected and processed for histology, immunohistochemistry, and scanning electron microscopy. Duodenal villus height (VH) increased (P ≤ 0.05) when probiotic was added to the diet. Chickens fed the probiotic had a significantly higher (P ≤ 0.05) percentage of intact villi compared to the other groups. The jejunum showed an increased VH in the group of birds supplemented with acidifiers. The ileum showed decreased (P ≤ 0.05) VH when probiotic was added to the diet, and increased VH when given acidifiers. Dietary supplementation of probiotic only or in combination with acidifiers showed a reduction (P ≤ 0.05) in the number of somatostatin immunoreactive cells (SIC) in the duodenal villi. A decrease in the number of SIC was also noted in the jejunal villi of birds receiving acidifiers. In conclusion, dietary supplementation with the probiotic, B. subtilis, or acidifiers improved the mucosal morphology of the small intestine in the broilers used in the present study. The 2 additives, however, did not show any synergistic effect on the intestinal morphology.

Localization of amylin-like immunoreactivity in the striped velvet gecko pancreas.

Immunohistochemical techniques were employed to investigate the distribution of amylin-like immunoreactive cells in the pancreas of gecko Homopholis fasciata. Four types of endocrine cells were distinguished: insulin immunoreactive (B cells), pancreatic polypeptide immunoreactive (PP cells), glucagon and pancreatic polypeptide immunoreactive (A/PP cells) and somatostatin immunoreactive cells (D cells). Pancreatic islets contained B, A/PP and D cells, whereas extrainsular regions contained B, D and PP cells. In the pancreatic islets, amylin-like immunoreactive cells corresponded to B cells, but not to A/PP or D cells. In the extrainsular regions, amylin-like immunoreactive cells corresponded to either B or PP cells. Amylin secreted from intrainsular B cells may regulate pancreatic hormone secretion in an autocrine and/or a paracrine fashion. On the other hand, amylin secreted from extrainsular PP and B cells, and/or intrainsular B cells may participate in the modulation of calcium homoeostasis in an endocrine fashion.

Selective plasticity of hippocampal GABAergic interneuron populations following kindling of different brain regions.

The vulnerability and plasticity of hippocampal GABAergic interneurons is a topic of broad interest and debate in the field of epilepsy. In this experiment, we used the electrical kindling model of epilepsy to determine whether seizures that originate in different brain regions have differential effects on hippocampal interneuron subpopulations. Long-Evans rats received 99 electrical stimulations of the hippocampus, amygdala, or caudate nucleus, followed by sacrifice and immunohistochemical or western blot analyses. We analyzed markers of dendritic (somatostatin), perisomatic (parvalbumin), and interneuron-selective (calretinin) inhibition, as well as an overall indicator (GAD67) of interneuron distribution across all major hippocampal subfields. Our results indicate that kindling produces selective effects on the number and morphology of different functional classes of GABAergic interneurons. In particular, limbic kindling appears to enhance dendritic inhibition, indicated by a greater number of somatostatin-immunoreactive (-ir) cells in the CA1 pyramidal layer and robust morphological sprouting in the dentate gyrus. We also found a reduction in the number of interneuron-selective calretinin-ir cells in the dentate gyrus of hippocampal-kindled rats, which suggests a possible reduction of synchronized dendritic inhibition. In contrast, perisomatic inhibition indicated by parvalbumin immunoreactivity appears to be largely resilient to the effects of kindling. Finally, we found a significant induction in the number of GAD67-cells in caudate-kindled rats in the dentate gyrus and CA3 hippocampal subfields. Taken together, our results demonstrate that kindling has subfield-selective effects on the different functional classes of hippocampal GABAergic interneurons. J. Comp. Neurol. 525:389-406, 2017. © 2016 Wiley Periodicals, Inc.

Identification and localization of gastrointestinal hormones in the skin of the bullfrog Rana catesbeiana during periods of activity and hibernation

Amphibian skin and its secretions contain a wide variety of biogenic amines and biologically active peptides, some of which are either identical or highly homologous to gastrointestinal hormones (GHs) of higher vertebrates. This study investigated the distribution density and immunoreactive (IR) intensity of 5-hydroxytryptamine (5-HT), gastrin (GAS), somatostatin (SS), pancreatic polypeptide (PP), neuropeptide Y (NPY) and glucagon (GLU) IR cells in the skin of the bullfrog Rana catesbeiana during periods of activity and hibernation. The results indicated that the six types of GHs were all present in the bullfrog skin and were most predominant in the epidermis and mucous glands. In dorsal skin, the density of the GHs-IR cells in mucous glands was higher than that in epidermis except for GAS-IR cells. In ventral skin, the density of 5-HT, PP and NPY-IR cells in mucous glands was also higher than that in the epidermis. During hibernation, the density of the six types of GHs-IR cells and the IR intensity of GAS, SS, NPY and GLU-IR cells in the epidermis of dorsal skin increased significantly. The IR intensity of SS, PP and NPY-IR cells in granular glands of ventral skin also increased significantly during hibernation. These results suggested that multiple types of GHs-IR cells present in the skin of R. catesbeiana, may play important roles in the regulation of the physiological functions of skin. Also, adaptive changes in the density and IR intensity of GHs-IR cells occurred during hibernation.

Stomach antral endocrine cells in patients with irritable bowel syndrome.

To the best of our knowledge, stomach antral endocrine cells have not previously been investigated in patients with irritable bowel syndrome (IBS). Thus, in the present study, 76 patients with IBS were examined (designated as IBS-total). Diarrhoea was the predominant symptom in 26 of these patients (IBS-D), while in 21 patients, the predominant symptoms were both diarrhoea and constipation (IBS-M) and in 29 patients the predominant symptom was constipation (IBS-C). Forty-three healthy subjects were enrolled as the controls. Stomach antral biopsy samples obtained from all of the subjects were immunostained using the avidin-biotin-complex method for serotonin, gastrin, somatostatin and serotonin transporter (SERT). The immunopositive cell densities and immunoreactivity intensities were determined by computer-aided image analysis. The density of the serotonin-immunoreactive cells was significantly decreased in the IBS-M patients and increased in the IBS-C patients relative to the controls. The immunoreactivity intensity did not differ significantly between the controls and IBS-total. The density of the gastrin-immunoreactive cells was significantly greater in the IBS-D, IBS-M and IBS-C patients than in the controls. The immunoreactivity intensity of gastrin was significantly greater in the IBS-D patients than in the controls. The density of the somatostatin-immunoreactive cells cells was significantly lower in the IBS-total, IBS-D, IBS-M and IBS-C patients than in the controls. The immunoreactivity intensities of both somatostatin and SERT did not differ significantly between the controls and IBS-total. The increase in gastrin cell density and the decrease in somatostatin cell density in all IBS subtypes may cause high levels of gastric secretion, which may in turn contribute to the high incidence of dyspepsia and gastro-oesophageal reflux observed in patients with IBS.

The regional distribution and frequency of endocrine cells in the Korean golden frog, Rana plancyi chosenica: an immunohistochemical study

Distribution patterns and the relative frequency of different types of endocrine cells were demonstrated in the alimentary tract of the Korean golden frog (Rana plancyi chosenica Okada), which is known as a Korean endemic species, for the first time. The alimentary tract of the frog was divided into six portions from the esophagus to the rectum. Most endocrine cells were found in the epithelial lining and were generally spindle-shaped with cytoplasmic processes ending in the lumen (open-typed cell), whereas cells that were spherical in shape (close-typed cell) were occasionally found in mucosal glands. Endocrine cells were stained for the following regulatory peptides: Sp-1/chromogranin A (Cg A), serotonin, somatostatin, gastrin, cholecystokinin (CCK)-8, bombesin, pancreatic polypeptide (PP), and glucagon. Cells stained for Cg A and serotonin were present throughout the entire alimentary tract. Somatostatin-immunoreactive (IR) cells were detected throughout the entire alimentary tract except the rectum. Cells stained for gastrin and CCK-8 were restricted to the pylorus, duodenum, and ileum, whereas bombesin-IR cells were restricted to the esophagus, antrum, and pylorus. Glucagon-containing cells were located in the esophagus, antrum, pylorus, and duodenum. Most of the IR cells occurred with the highest frequency in the pylorus except for cells stained for somatostatin and bombesin, which showed the highest frequencies in the antrum and serotonin-IR cells, which showed in the duodenum, respectively. No PP-stained cells were detected in this study. In conclusion, distribution patterns and the frequency of these endocrine cells not only correspond well with other Salienta species but some deviating patterns were also observed.

Distinctive expression and cellular distribution of dopamine receptors in the pancreatic islets of rats.

Activation of the dopamine (DA) D2 receptor inhibits glucose-stimulated insulin secretion in isolated rodent islets in vitro; however, no information is available regarding the cellular localization of DA receptors (DRs, including D1-D5 receptors) in pancreatic islets in situ. We investigate the protein expression and cellular localization of five types of DRs in pancreatic islets by means of Western blotting and double-labeling immunofluorescence in both normal control and alloxan-induced type 1 diabetes model (T1DM) rats. In control rats, D1 immunoreactivity (-IR) was distributed in the core of the islet and co-localized with insulin-IR, D2-IR was peripherally distributed and found only in somatostatin-immunoreactive cells and D5-IR was co-localized with glucagon-IR and pancreatic polypeptide-IR. No IR for either the D3 or D4 receptor was observed in rat islets. The protein level of the D1 receptor was reduced in T1DM rats (D1/D-glyceraldehyde-3-phosphate dehydrogenase [GAPDH], 0.63 ± 0.05 in control rats compared with 0.16 ± 0.03 in T1DM rats, n = 8, P < 0.05) but no significant alteration was detected in the protein expression of either the D2 receptor (D2/GAPDH, 0.48 ± 0.04 compared with 0.43 ± 0.04, n = 8, P = 0.42) or the D5 receptor (D5/GAPDH, 0.50 ± 0.04 compared with 0.47 ± 0.04, n = 8, P = 0.58). The present study is the first clear demonstration of the protein expression and cellular localization of the D1, D2 and D5 receptors in rat pancreatic islets and provides crucial morphological evidence for further investigations of the underlying mechanism regarding the DA regulation of pancreatic endocrine function.

Endocrine cells in the ileum of patients with irritable bowel syndrome.

To study the ileal endocrine cell types in irritable bowel syndrome (IBS) patients. Ninety-eight patients with IBS (77 females and 21 males; mean age 35 years, range 18-66 years) were included, of which 35 patients had diarrhea (IBS-D), 31 patients had a mixture of both diarrhea and constipation (IBS-M), and 32 patients had constipation (IBS-C) as the predominant symptoms. The controls were 38 subjects (26 females and 12 males; mean age 40 years, range 18-65 years) who had submitted to colonoscopy for the following reasons: gastrointestinal bleeding, where the source of bleeding was identified as hemorrhoids (n = 24) or angiodysplasia (n = 3), and health worries resulting from a relative being diagnosed with colon carcinoma (n = 11). The patients were asked to complete the: Birmingham IBS symptom questionnaire. Ileal biopsy specimens from all subjects were immunostained using the avidin-biotin-complex method for serotonin, peptide YY (PYY), pancreatic polypeptide (PP), enteroglucagon, and somatostatin cells. The cell densities were quantified by computerized image analysis, using Olympus cellSens imaging software. The gender and age distributions did not differ significantly between the patients and the controls (P = 0.27 and P = 0.18, respectively). The total score of Birmingham IBS symptom questionnaire was 21 ± 0.8, and the three underlying dimensions: pain, diarrhea, and constipation were 7.2 ± 0.4, 6.6 ± 0.4, and 7.2 ± 0.4, respectively. The density of serotonin cells in the ileum was 40.6 ± 3.6 cells/mm² in the controls, and 11.5 ± 1.2, 10.7 ± 5.6, 10.0 ± 1.9, and 13.9 ± 1.4 cells/mm² in the all IBS patients (IBS-total), IBS-D, IBS-M, and IBS-C patients, respectively. The density in the controls differed significantly from those in the IBS-total, IBS-D, IBS-M, and IBS-C groups (P < 0.0001, P = 0.0001, P = 0.0001, and P < 0.0001, respectively). There was a significant inverse correlation between the serotonin cell density and the pain dimension of Birmingham IBS symptom questionnaire (r = -0.6, P = 0.0002). The density of PYY cells was 26.7 ± 1.6 cells/mm(2) in the controls, and 33.1 ± 1.4, 27.5 ± 1.4, 34.1 ± 2.5, and 41.7 ± 3.1 cells/mm² in the IBS-total, IBS-D, IBS-M, and IBS-C patients, respectively. This density differed significantly between patients with IBS-total and IBS-C and the controls (P = 0.03 and < 0.0001, respectively), but not between controls and, IBS-D, and IBS-M patients (P = 0.8, and P = 0.1, respectively). The density of PYY cells correlated significantly with the degree of constipation as recorded by the Birmingham IBS symptom questionnaire (r = 0.6, P = 0.0002). There were few PP-, enteroglucagon-, and somatostatin-immunoreactive cells in the biopsy material examined, which made it impossible to reliably quantify these cells. The decrease of ileal serotonin cells is associated with the visceral hypersensitivity seen in all IBS subtypes. The increased density of PYY cells in IBS-C might contribute to the constipation experienced by these patients.

Gastrointestinal Viral Load and Enteroendocrine Cell Number Are Associated with Altered Survival in HIV-1 Infected Individuals

Human immunodeficiency virus type 1 (HIV-1) infects and destroys cells of the immune system leading to an overt immune deficiency known as HIV acquired immunodeficiency syndrome (HIV/AIDS). The gut associated lymphoid tissue is one of the major lymphoid tissues targeted by HIV-1, and is considered a reservoir for HIV-1 replication and of major importance in CD4+ T-cell depletion. In addition to immunodeficiency, HIV-1 infection also directly causes gastrointestinal (GI) dysfunction, also known as HIV enteropathy. This enteropathy can manifest itself as many pathological changes in the GI tract. The objective of this study was to determine the association of gut HIV-1 infection markers with long-term survival in a cohort of men who have sex with men (MSM) enrolled pre-HAART (Highly Active Antiretroviral Therapy). We examined survival over 15-years in a cohort of 42 HIV-infected cases: In addition to CD4+ T cell counts and HIV-1 plasma viral load, multiple gut compartment (duodenum and colon) biopsies were taken by endoscopy every 6 months during the initial 3-year period. HIV-1 was cultured from tissues and phenotyped and viral loads in the gut tissues were determined. Moreover, the tissues were subjected to an extensive assessment of enteroendocrine cell distribution and pathology. The collected data was used for survival analyses, which showed that patients with higher gut tissue viral load levels had a significantly worse survival prognosis. Moreover, lower numbers of serotonin (duodenum) and somatostatin (duodenum and colon) immunoreactive cell counts in the gut tissues of patients was associated with significant lower survival prognosis. Our study, suggested that HIV-1 pathogenesis and survival prognosis is associated with altered enteroendocrine cell numbers, which could point to a potential role for enteroendocrine function in HIV infection and pathogenesis.

An immunohistochemical study of somatostatin in the stomach and the small intestine of the African ostrich (Struthio camelus)

The aim of the present study was to clarify the distribution and relative frequencies of somatostatin (SST)-producing cells in the stomach and the small intestine of the ostrich by using immunohistochemistry. The results indicated that somatostatin-immunoreactive (SST-IR) cells were distributed in mucosal layers of the proventriculus, duodenum, jejunum and ileum. However, no immunoreactivity was observed in the gizzard. SST-IR cells were found at the lower part of glandular lobule in the proventriculus, which were oval and round generally. SST-IR cells were present in the mucous membrane of entire small intestine of the ostrich. SST-IR cells had round and spherical shapes (closed-type cells), or spindle and pyriform shapes (open-type cells) in the small intestine. SST-positive cells were localized preferentially in the proventriculus of the 60-day-old ostrich. These results indicated that SST might be involved in functional and developmental regulation of gastrointestinal tract of the ostrich.

The Distribution of Gastrin, Somatostatin and Glucagon Immunoreactive (IR) Cells in Ostrich Stomach During the Pre- and Post-hatching Period

Peptides of the gastrointestinal tract play a significant role in the digestive processes and the development of the body; therefore, it is important to have an understanding of location and distribution of gastrin, somatostatin and glucagon immunoreactive (IR) cells in the stomach mucosa of growing birds. For this purpose, 6 embryos and 37 chicks from an ostrich farm in Latvia were used. Tissue samples were collected from the proventriculus - superficial and deep glandular region and from the ventriculus - side wall and pyloric region. The number of cells was determined in 10 mucosal fields of each tissue sample. For statistical analysis, the one-way anova method was used. Gastrin IR cells regarding the stomach mucosa were found only in the pyloric region. Somatostatin IR cells were most densely located in the pyloric region too, but some cells were also discovered in the mucosa of proventriculus and ventriculus. Glucagon IR cells were found in the epithelium of the deep glands of the proventriculus and only some cells of the superficial glands of the proventriculus, and the ventriculus side wall mucosa. Gastrin and somatostatin IR cells were present in a comparatively large quantity in the ostrich chicks' ventriculus - pyloric region yet not long before hatching. They were located deep in the mucosa of pyloric glands, and their number tended to increase with birds advancing in age.

Immunohistochemical study of the endocrine cells in the pancreas of the actinopterygian fishes ( Actinopterigii)

The endocrine tissue in the pancreas of 10 actinopterygian fishes (Actinopterigii) species was investigated in present study. Insulin-immunoreactive cells in the most of the studied species (except A. Anguilla, E. Lucius, C. Carpio) had the spherical shape. Glucagon-immunoreactive and somatostatin-immunoreactive cells had the spindle shape with cytoplasmic processes in all species. Insulin-immunoreactive cells were located in the central region of the pancreatic islets; glucagon-immunoreactive cells were located on islet periphery in the most of these species. In A. ruthenus the islets contained only insulin-positive cells. In this case glucagon-and somatostatin-positive cells were distributed around the islets, single cells and small clasters were scaterred throughout the pancreas. In the islets of A. Anguilla, insulin-immunoreactive cells were found in the peripheral region, glucagon-immunoreactive cells were located in the central region. The observed polymorphism of the islets and endocrine cells can not be explained by feeding habits of fishes.

Effects of CP 55,940--agonist of CB1 cannabinoid receptors on ghrelin and somatostatin producing cells in the rat pancreas.

Cannabinoids participate in the modulation of numerous functions in the human organism, increasing the sense of hunger, affecting carbohydrate and lipid metabolism, and controlling systemic energy balance mechanisms. Moreover, they influence the endocrine system functions, acting via two types of receptors, CB1 and CB2. The aim of the present study was to examine the number, distribution and activity of ghrelin and somatostatin producing endocrine cells in the pancreas of rats after a single administration of selective CP 55,940 agonist of CB1 receptor. The study was performed on 20 rats. Neuroendocrine cells were identified by immunohistochemical reactions, involving specific antibodies against ghrelin and somatostatin. The distribution and number of ghrelin- and somatostatin-immunoreactive cells were separately studied in five pancreas islets of each section. A performed analysis showed a decreased number of somatostatin-immunoreactive cells and a weak immunoreactivity of ghrelin and somatostatin containing neuroendocrine cells in the pancreatic islets of experimental rats, compared to control animals. The obtained results suggest that a single administration of a selective CP 55,940 agonist of CB1 receptor influences the immunoreactivity of endocrine cells with ghrelin and somatostatin expression in the pancreas islets.

Somatostatin‐immunoreactive senile plaque‐like structures in the frontal cortex and nucleus accumbens of aged tree shrews and Japanese macaques

Previously, we demonstrated decreased expression of somatostatin mRNA in aged macaque brain, particularly in the prefrontal cortex. To investigate whether or not this age-dependent decrease in mRNA is related to morphological changes, we analyzed somatostatin cells in the cerebra of aged Japanese macaques and compared them with those in rats and tree shrews, the latter of which are closely related to primates. Brains of aged macaques, tree shrews, and rats were investigated by immunohistochemistry with special emphasis on somatostatin. We observed degenerating somatostatin-immunoreactive cells in the cortices of aged macaques and tree shrews. Somatostatin-immunoreactive senile plaque-like structures were found in areas 6 and 8 and in the nucleus accumbens of macaques, as well as in the nucleus accumbens and the cortex of aged tree shrews, where amyloid accumulations were observed. Somatostatin degenerations may be related to amyloid accumulations and may play roles in impairments of cognitive functions during aging.

High densities of serotonin and peptide YY cells in the colon of patients with lymphocytic colitis

To investigate colonic endocrine cells in lymphocytic colitis (LC) patients. Fifty-seven patients with LC were included. These patients were 41 females and 16 males, with an average age of 49 years (range 19-84 years). Twenty-seven subjects that underwent colonoscopy with biopsies were used as controls. These subjects underwent colonoscopy because of gastrointestinal bleeding or health worries, where the source of bleeding was identified as haemorrhoids or angiodysplasia. They were 19 females and 8 males with an average age of 49 years (range 18-67 years). Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. Biopsies were fixed in 4% buffered paraformaldehyde, embedded in paraffin and cut into 5 μm-thick sections. The sections immunostained by the avidin-biotin-complex method for serotonin, peptide YY (PYY), pancreatic polypeptide (PP) enteroglucagon and somatostatin cells. The cell densities were quantified by computerised image analysis using Olympus software. The colon of both the patient and the control subjects were macroscopically normal. Histopathological examination of colon biopsies from controls revealed normal histology. All patients fulfilled the diagnosis criteria required for of LC: an increase in intraepithelial lymphocytes (> 20 lymphocytes/100 epithelial cells) and surface epithelial damage with increased lamina propria plasma cells and absent or minimal crypt architectural distribution. In the colon of both patients and control subjects, serotonin-, PYY-, PP-, enteroglucagon- and somatostatin-immunoreactive cells were primarily located in the upper part of the crypts of Lieberkühn. These cells were basket- or flask-shaped. There was no statistically significant difference between the right and left colon in controls with regards to the densities of serotonin- and PYY-immunoreactive cells (P = 0.9 and 0.1, respectively). Serotonin cell density in the right colon in controls was 28.9 ± 1.8 and in LC patients 41.6 ± 2.6 (P = 0.008). In the left colon, the corresponding figures were 28.5 ± 1.9 and 42.4 ± 2.9, respectively (P = 0.009). PYY cell density in the right colon of the controls was 10.1 ± 1 and of LC patients 41 ± 4 (P = 0.00006). In the left colon, PYY cell density in controls was 6.6 ± 1.2 and in LC patients 53.3 ± 4.6 (P = 0.00007). The change in serotonin cells could be caused by an interaction between immune cells and serotonin cells, and that of PYY density might be secondary.

Low densities of serotonin and peptide YY cells in the colon of patients with irritable bowel syndrome.

BackgroundThe gut hormones are important in regulating gastrointestinal motility. Disturbances in gastrointestinal motility have been reported in patients with irritable bowel syndrome (IBS). Reduced endocrine cell density, as revealed by chromogranin A, has been reported in the colon of IBS patients.AimsTo investigate a possible abnormality in the colonic endocrine cells of IBS patients.MethodsA total of 41 patients with IBS according to Rome Criteria III and 20 controls were included in the study. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. The biopsies were immunostained for serotonin, peptide YY (PYY), pancreatic polypeptide (PP), entroglucagon, and somatostatin cells. Cell densities were quantified by computerized image analysis.ResultsSerotonin and PYY cell densities were reduced in the colon of IBS patients. PP, entroglucagon, and somatostatin-immunoreactive cells were too few to enable reliable quantification.ConclusionThe cause of these observations could be primary genetic defect(s), secondary to altered serotonin and/or PYY signaling systems and/or subclinical inflammation. Serotonin activates the submucosal sensory branch of the enteric nervous system and controls gastrointestinal motility and chloride secretion via interneurons and motor neurons. PYY stimulates absorption of water and electrolytes, and inhibits prostaglandin (PG) E2, and vasoactive intestinal peptide, which stimulates intestinal fluid secretion and is a major regulator of the “ileal brake”. Although the cause and effect relationship of these findings is difficult to elucidate, the abnormalities reported here might contribute to the symptoms associated with IBS.