Exocrine Part Research Articles

The histogenesis of developing human fetal pancreas – an electron microscopic study

Background: For the prospect of successful replacement therapies in treatment of Diabetes mallitus it is necessary to know events occurring during normal human pancreas development. Literature of human pancreas development are few in number as well as mainly related to first trimester because of ethical and technical difficulties. So the study was conducted on 12 fetuses from 12 gestational weeks (GW) to 5 months of infant to know normal development of exocrine and endocrine part of human pancreas.Material and Methods: Human fetalpancreases were screened by haematoxyline and eosin staining and done electron microscopy for suitable specimens to know ultrastructural detail of fetal pancreas.Results:It was observed arborized tubules, the cells budding out from these tubules differentiated into primitive acini and islets in 12thGW. At 14 weeks scanty granules were observed in the endocrine cells which coincided with the capillary invasion of the islets. The ducts and acini were surrounded by well-organized connective tissue. The acinihad elongated cells, small amount of cytoplasm and large open face euchromatic nuclei with single nucleolus. The mature form of islets of Langerhans was observed close to the acini and duct in 20 GW fetus. Connective tissue around the duct was well organized.No significant developmental change was observed early postnatal, infant.Conclusion: The development of both component exocrine as well as endocrine part of human fetal pancreas was studied by light and electron microscopy. Observations suggested that the fetal pancreas contained mainly ducts, few acini, many centroacinar cells, and large undifferentiated tissue.

A frog-based approach to study pancreatic development

Pancreatic development is a yet incomplete understood process. This is mainly due to a lack of fast and efficient model systems. While mouse models are time-consuming and cost-intensive, pluripotent stem cell based assays require a complex cocktail of growth factors to drive them to the respective lineage. Herein, we approached this hurdle by using Xenopus laevis as an in vivo model and provide proof of concept by targeting transcription factors of potential relevance for pancreatic development. A series of methods is applied (i) morpholino based UTR-targegting at different embryonic stages (ii) in situ hybridization to visualize exocrine and endocrine parts of the pancreas (iii) cDNA injection for phenotype rescue experiments. Thus, we provide a unique, fast and efficient pancreatic development modell suitable to study gene function in vivo.

THE PROTECTIVE EFFECT OF CAMEL’S MILK, IN COMPARISON TO THYMOQUINONE, ON STREPTOZOTOCIN-INDUCED DAMAGE IN THE PANCREAS OF ALBINO RATS

Streptozotocin has been used extensively to produce an experimental animal model for diabetes mellitus. The present study was undertaken to investigate the protective effect of camel milk, in comparison to thymoquinone, against streptozotocin-induced damage in the pancreas. The rats were divided into four groups as follows. (1) Control group, (2) Diabetic group with a single intraperitoneal injection of streptozotocin (50 mg/kg body weight), (3) Diabetic group treated with camel’s milk (CM) orally and daily at a dose of 2 ml/rat, (4) Diabetic group treated with thymoquinone (TQ) orally and daily at a dose of 50 mg/kg body weight. After 2 months, the animals were sacrificed and blood samples were collected for the detection of serum glucose levels. The pancreas was prepared for histopathological, immunohistochemical and ultrastructural studies. The histological examination of diabetic pancreas showed vacuolation and shrinkage of the islets of Langerhans. The exocrine part of the gland showed vacuolization and flattening of the lining epithelium of the acini. Dense collagen fibres around the acini, blood vessels and pancreatic ducts were also detected. The immunoreactivity or anti-insulin antibodies was markedly decreased. Electron microscopic examination of the diabetic group showed marked changes in pancreatic acini represented by dilatation of the rough endoplasmic reticulum, decrease of secretory granules, vacuolization of the cytoplasm, damage of the mitochondria, and dilatation of the perinuclear space. The β-cells of the diabetic rats showed decrease in the number of secretory granules, heterochromatic nuclei and cytoplasmic vacuolation. CM and TQ improved the histological and ultrastructural changes of the β-cells and exocrine acini epithelium, which almost reverted to their normal structure. These factors increased insulin immunoreactivity and decreased the elevated glucose concentrations. However, insulin immunoreactivity was found in the majority of the pancreatic islets in diabetic rats treated with CM or TQ.

The effect of intermedin8-47 on microcirculation disturbance of acute pancreatitis in rats

Objective To establish rat model of acute pancreatitis and observe the influence of Intermedin8-47 (IMD8-47) on microcirculation endothelial cell in the exocrine and endocrine parts of pancreas.Methods Rat model of acute pancreatitis is established by subcutaneous injection of bombesin:(1) Evaluation of pancreatic edema and detection of the serum amylase level; (2) Pathology observation of pancreatic tissue by Light-microscopy; (3) Observation of ultrastructure changes of microcirculation endothelial cell in the parts of exocrine and endocrine by transmission electron microscope (TEM) ; (4)Detection of the expression of eNOS and VE-cadherin in endothelial cells by immune histochemical method.Results (1) Compared with IMD8-47 intervention group,AP Group had more serious edema,higher level of serum amylase and pathological score of pancreatic tissue.The difference between the two groups was statistically significant (P =0.035) ; (2) TEM showed that after exogenous IMD8-47 intervention,the ultrastructure of blood capillary endothelial cells in the parts of exocrine and endocrine changed significantly; (3) Immunohistochemical section showed that the eNOS and VE-cadherin expressions was significantly different among Control group,IMD8-47 intervention group and AP model group (P ＜ 0.05).Conclusion Exogenous IMD8-47 may contribute to protecting pancreatic tissue by the different effects on pancreatic exocrine and endocrine parts. Key words: Acute pancreatitis; Microcirculation disturbance; Intermedin 8-47 ; eNOS ; VE-cadherin

Type 1 diabetes as an autoimmune disease: the evidence

To the Editor: The recent commentary [1] on the role of autoimmunity in the pathogenesis of type 1 diabetes, in response to a consensus definition of insulitis in human type 1 diabetes [2], is an opportunity to review the evidence in favour of type 1 diabetes being an autoimmune disease, and the absence of any direct evidence to the contrary. The authors stress that type 1 diabetes is about the only autoimmune disease without an approved immune treatment [1]. Sad but true, but not for lack of trying. Since the seminal review on the pathophysiology of type 1 diabetes, published 33 years ago [3], evidence has been accumulating that type 1 diabetes is an autoimmune disease. Practically every type of immunotherapy that biotechnology has provided has been applied to type 1 diabetes [1, 4], yet there is only one partial success story: the administration of large doses of anti-CD3 antibody for 1 week results 4 years later in half the insulin requirement in treated subjects vs placebo and better glycaemic control [5]. A recombinant proinsulin DNA vaccine given intramuscularly (the first of its kind) has also shown some promise, but more knowledge is needed in order to render it more effective [6]. Ethical concerns and technical reasons prevent investigators from obtaining pancreatic tissue (and, thus, islets, which constitute 1% of the pancreas and are interspersed throughout the exocrine part) or proximal lymph node tissue, from newly diagnosed patients (mostly young people with near-normal life expectancy). Careful laparoscopic sampling of pancreas has been carried out in newly diagnosed adult patients, with findings generally confirming those from samples obtained post-mortem from one to several months after clinical onset [7]. Type 1 diabetes is clinically manifested when 80–85% of the islet beta cells are either dead or not functioning, so such histological samples provide even fewer islets to assess autoimmune phenomena. The immunocyte infiltration in the islets of a type 1 diabetic pancreas is not synchronous, but is highly beta cell specific: hardly found in islets devoid of beta cells because of prior destruction, and mostly found in islets where insulin is still present in beta cells. The generally poor regenerative potential of human beta cells tilts the balance towards their destruction [8], thus limiting the scope of the autoimmune attack: once finished with the beta cells of one islet, the sensitised immunocytes move on to their next target. The authors are correct in stating that we know nothing about the initial trigger(s) of beta cell autoimmunity [1]. In fact, there is evidence of abnormalities in the blood lipidome from the birth of prospectively followed subjects that manifest type 1 diabetes, without any parallel evidence of autoimmunity [9]. Whatever the initial trigger, the path followed most invariably concerns autoantibody formation and T cell proliferation to beta cell autoantigens. The genetics of type 1 S. A. Paschou Department of Diabetes and Endocrinology, Hellenic Red Cross Hospital, Athens, Greece

Finding insights of Pancreas development

Pancreas is organ which contains digestive enzymes that assist the absorption of nutrients to be digested by small intestine which makes this gland as main energy regulator which up regulates expression to counter metabolism or down regulates in promoting or maintaining blood pressure etc. It is made up of exocrine and endocrine parts which have enzymes & millions of cells regulating its tissue specific expression. Multiple pathways too are associated with pancreatic mechanism which is directly epicenter in modulating energy mechanism throughout organism behavior. We in present study, wants to find out mechanism of pancreatic development with its signaling. Pancreatic beta cell, alpha cell, delta cells, pp cells and all endocrine part is mainly develops by differentiation of PDX gene which further divides and interacts with other differentiation factors of genes which promoted maintenance and development of Islets of Langerhans. We have identified Driver genes involved in this mechanism with their interacting passenger genes which are associated in development of Langerhans. Although, we to have created driver genes interactome of all drivers in development with their respective passengers. For analyses of gene expression we have modeled all gene expression to know their function at proteomic level with this we know that what will be the expression scenario of multiple proteins at structure level. We have used many system biological tools like Cytoscape, Modeller, Grommacs with online tools such as Castp, Phyre2, ifold etc.

DYNAMICS OF STRUCTURAL CHANGES IN PANCREAS DURING PROLONGED EXPERIMENTALLY INDUCED HYPOPINEALISM

In the experiment on young mature male-rabbits was studied the structural changes of the pancreas in the dynamics of hypopinealism induced by prolonged day-and-night lighting. It was established that in the result of day-and-night light exposure for 1–5 months in the pancreas occur growing in time damaging processes, that characterized by the degradation of structures both endocrine and exocrine part of the organ. At hypopinealism take place progressing death of β-cells of Langerhans islets and too high voltage of the β-cells that has remained as functioning. The data obtained suggest that the prolonged effect of light in the night-time should be attributed to a strong negative environmental factors, which by violating of structure and hormonal activity of the pineal gland are able to provoke destructive processes in the pancreas.

Immunohistochemical study of the pancreas of patients with long termed diabetes mellitus type 1

There has been a concept of the autoimmune pathogenesis of DM1 developed in the diabetology. The basic notion of the concept is that a root cause of a death of the insulin containing B-cells is in an autoimmune aggression against them (1, 2). There is a significant destruction of B-cells observed in patients with DM1 prior to diagnosis. In patients with recently diagnosed DM1 the autoimmune processes has manifested in a form of insulitis chronic inflammatory infiltration of mononuclear cells in the residual cells of the pancreatic islets (3). Although considered typical for recent onset disease, the insulitis has been described only in approximately 150 cases per 100 years (4). It is known that DM1 is accompaniedby peripheral nervous system lesions wich leads to a reduction of a life span and mortality enlargement. It has been suggested that peripheral nervous system lesions, as well as B-cell destruction, in DM1 patients also has an autoimmune nature. Moreover, experiments on DM1 animal models (NOD mice) shows the autoimmune destruction of pancreatic nerve terminals at a beginning of the DM1 progression (5-11). According to this model the autoimmune reaction on B-cells develops after T-cells infiltration into the pancreatic islets as a result of similarities between B-cells and neurons in some synthezied proteins and intracellular processes, and high sensitivity of B-cells to the cytokine induced destruction (5, 6, 12,13).

Auto-antibodies in patients with inflammatory bowel disease unclassified.

Inflammatory bowel disease unclassified (IBDU) is considered to be an aberrant immune response with loss of tolerance to many antigens. This paper tries to address whether there is any value to test for auto-antibodies in such patients. 60 patients with inflammatory bowel disease unclassified participated in the study. Auto-antibodies to nuclear antigen, intestinal goblet cell, exocrine part of pancreatic acinar cells, perinuclear antineutrophil cytoplasmic, cytoplasmic antineutrophil cytoplasmic and Saccharomyces cerevisiae were tested and compared to 20 ulcerative colitis (UC) patients and 30 healthy controls matched for age and sex. There was a significant difference (p=0.000) between patients and control group in anti-exocrine part of pancreatic acinar cells, perinuclear antineutrophil cytoplasmic and Saccharomyces cerevisiae auto-antibodies. There was also a significant difference between IBDU and UC patients in the auto-antibodies directed against intestinal goblet cells, (p=0.000) exocrine part of pancreas (p=0.000) and anti Saccharomyces cerevisiae antibody (p=0.000). Due to the autoimmune nature of indeterminate colitis, involvement of some antigens from gastrointestinal tract or the bile system in the initiation of this disease is likely.

Histological and immunohistochemical study of the effect of orlistat on the exocrine pancreas of adult female albino rat

Introduction Orlistat is considered to be a safe and effective drug to treat obesity by decreasing the absorption of digested fat. However, many cases of orlistat-induced pancreatitis were reported. Aim of the study This study was carried out to study the effect of orlistat on the histological structure of the exocrine part of the pancreas, and to evaluate the possibility of recovery after its withdrawal. Materials and methods Forty-eight adult female albino rats were divided into; group I (control), group II (each animal received 32 mg orlistat orally once daily for 8 weeks) and group III (recovery), which received the same dose of orlistat and was left without any treatment for another 8 weeks. The pancreas from each animal was dissected out and processed for histological (light microscopic and electron microscopic) study. The result of immunohistochemical (inducible nitric oxide synthase) stain was statically analyzed. Results Sections of orlistat-treated rats showed variable disturbance of normal architecture of the pancreatic acini, congestion of blood vessels, and widening of the spaces between the acini. The acinar cells showed vacuolation of their cytoplasm. Immunostaining of inducible nitric oxide synthase revealed significant increase in the reaction in group II. Ultrastructure examination showed dilated rough endoplasmic reticulum, destroyed mitochondria, and dissolution of zymogene granules in some acinar cells. These findings were improved after stoppage of the drug. Conclusion Orlistat has a harmful effect on pancreatic acini. Thus, it must be taken under medical observation.

Adrenocorticotropic tumor cells transplanted into mouse embryos affect pancreatic histogenesis

A wide range of individual differences exist in the total number of functional and structural units in each organ, such as β cells in pancreatic islands, and these units are the basis of the organ's overall function, including its functional reserve. The endocrine environment may influence organ histogenesis, during which functional and structural units are formed and increase in number. We analyzed the effects of a continuous high level of adrenocorticotropic hormone (ACTH) and/or secondarily induced glucocorticoid on histogenesis of the pancreas in mouse embryos. Pituitary tumor-derived AtT20 cells, which secrete ACTH continuously, were injected subcutaneously into mouse embryos at embryonic day (E) 12.5, and the embryos were allowed to develop exo utero until E18.5 (AtT20 group). E18.5 AtT20 group embryos with high ACTH levels (23.74 ± 6.19 ng/mL vs control group, 0.48 ± 0.40 ng/mL, P < 0.05) were examined for the effects on histogenesis of the pancreas. Using serial sections of the E18.5 pancreas, we stereologically measured the volumes, and counted total cell numbers and numbers of mitotic or pyknotic cells of the whole pancreas, endocrine and exocrine cells, and glucagon-immunopositive α cells and insulin-immunopositive β cells in the endocrine part. Although the volumes of the whole pancreas and exocrine part did not change significantly, in the AtT20 group the endocrine part was significantly larger, with fewer pyknotic cells and lower ratios of α and β cells than in the control group. These results suggest that the high level of ACTH and/or glucocorticoid affects histogenesis of the pancreas.

Effects of severe hyperglycaemia in pregnancy and early overfeeding on islet development and insulin resistance

Study the effects of early overfeeding in the adult offspring of mother with severely hyperglycaemia in pregnancy to islet development and insulin resistance. Thirty healthy female Wistar rats were mated with 10 male Wistar rats and the morning on which sperm were found in three different visual fields of the vaginal smear was designated pregnancy day 1. The pregnant rats were intraperitoneally administered with Streptozotocin (STZ, 50 mg/L) on 5th day of pregnancy, and blood glucose exceeded 20 mmol/L to induce severely gestational diabetes mellitus (SDM) model. The pregnant Wistar rats were assigned to two experimental groups: SDM (n = 16) and control (n = 8). Litter size reduction in the lactation period induced early postnatal overfeeding model. Offspring were divided into three groups according to the level of blood glucose in pregnancy and feeding patterns in lactation: (1) control group (CG): euglycemia in pregnancy, eight pups in lactation; (2) severely gestational diabetes mellitus-normal feeding (SDM-N): severely gestational diabetes mellitus, eight pups in lactation; (3) severely gestational diabetes mellitus-overfeeding (SDM-O): severely gestational diabetes mellitus, four pups lactation. At the end of the lactation period, all pups were fed standard laboratory chow adlibitum until the date of the experiments. Offspring body weight was measured weekly after ablactation. Serum insulin was measured by enzyme-linked immunosorbent assay (ELISA) and pancreatic islet morphology was analyzed by immunohistochemistry (IHC) in all three groups at 26 weeks of age. (1) Blood glucose of pregnant Wistar rats: SDM (28.3 ± 5.1) mmol/L was statistically higher than control (6.3 ± 1.4) mmol/L (P < 0.05). (2) Growth rates of body weight in 3-7 weeks and 3-9 weeks: SDM-N: (4.6 ± 1.3)% and (6.8 ± 2.5)%, SDM-O: (3.2 ± 0.7)% and (4.6 ± 1.2)%, CG: (2.9 ± 0.6)% and (4.1 ± 0.8)%. The growth rates of body weight in SDM-N and SDM-O were both significantly higher than those in CG (P < 0.05). (3) Body weight at 26 weeks: CG: (486 ± 132) g, SDM-N: (387 ± 115) g, SDM-O: (382 ± 122) g. There was no statistical difference among the three groups (P > 0.05). (4) Fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model of insulin resistance (HOMA-IR) and insulin sensitivity index (ISI): at 26 weeks, the SDM-offspring has normal FPG, but more insulin was needed to keep it normal. The insulin level of SDM-O [(12.6 ± 3.3) mU/L] was statistically higher than those of SDM-N [(10.9 ± 3.3) mU/L] and CG [(8.6 ± 0.8) mU/L] (P < 0.05). The ISI of SDM-O (0.020 ± 0.006) was significantly smaller than its HOMA-IR (2.40 ± 0.62, P < 0.05). (5) The morphological change of pancreatic islet: The islets of CG and SDM-N were round or ellipse and have clear boundary between endocrine and exocrine parts and the β cells distributed equally. However, SDM-O islets were not of uniform size and most of islets were hyperplasia and hypertrophy. (6) Relative β cell area of pancreas, β-cell area and islet size: SDM-O: (1.81 ± 0.31)%, (57.1 ± 3.2)% and (39,067 ± 3308) µm(2); SDM-N:(1.34 ± 0.43)%, (60.9 ± 0.6)% and (30,570 ± 4824) µm(2); CG: (1.11 ± 0.26)%, (63.7 ± 2.7)% and (26,443 ± 4431) µm(2). SDM-O has significantly increasing β-cell mass, hypertrophic islet size and slightly decreasing β-cell percentage compared with other two groups (P < 0.05). The exposure of severely hyperglycemia in pregnancy induces low weight infant and postnatal catch-up growth leading to the possibility of insulin resistance (IR) in adult and early postnatal overfeeding will accelerate such course. Islet morphology of SDM-N has no significant change, indicating that maternal diabetes mainly affected β-cell function but not islet morphological features. SDM overfeeding results in early impairment of islet morphology and function, indicating that the compensation ability of islets has already been impaired and the risk of further development of impaired glucose tolerance (IGT) and diabetes. In conclusion, the nutritional environment in early life (duration of pregnancy and lactation) participate in the metabolic programming in adulthood.

Distinct Phenotype and Function of NK Cells in the Pancreas of Nonobese Diabetic Mice

Little is known about target organ-infiltrating NK cells in type 1 diabetes and other autoimmune diseases. In this study, we identified NK cells with a unique phenotype in the pancreas of NOD mice. Pancreatic NK cells, localized to the endocrine and exocrine parts, were present before T cells during disease development and did not require T cells for their infiltration. Furthermore, NK cells, or NK cell precursors, from the spleen could traffic to the pancreas, where they displayed the pancreatic phenotype. Pancreatic NK cells from other mouse strains shared phenotypic characteristics with pancreatic NK cells from NOD mice, but displayed less surface killer cell lectin-like receptor G1, a marker for mature NK cells that have undergone proliferation, and also did not proliferate to the same extent. A subset of NOD mouse pancreatic NK cells produced IFN-gamma spontaneously, suggesting ongoing effector responses. However, most NOD mouse pancreatic NK cells were hyporesponsive compared with spleen NK cells, as reflected by diminished cytokine secretion and a lower capacity to degranulate. Interestingly, such hyporesponsiveness was not seen in pancreatic NK cells from the nonautoimmune strain C57BL/6, suggesting that this feature is not a general property of pancreatic NK cells. Based on our data, we propose that NK cells are sentinel cells in a normal pancreas. We further speculate that during inflammation, pancreatic NK cells initially mediate proinflammatory effector functions, potentially contributing to organ-specific autoimmunity, but later become hyporesponsive because of exhaustion or regulation.

Solitary concomitant endocrine tumor and ductal adenocarcinoma of pancreas

Pancreatic tumors with combined exocrine and endocrine features are rare. Most reported cases are classified as mixed exocrine and endocrine carcinoma of the pancreas. We report the first case of solitary concomitant endocrine tumor and ductal adenocarcinoma of the pancreas. A 58-year-old patient was admitted for uncontrolled diabetes mellitus and body weight loss. The tumor was fortuitously discovered in the pancreatic tail after a tumor survey panel. Grossly, the solitary tumor had a central fibrous band that clearly divided it into two parts. On microscopic examination, the tumor contained both endocrine and exocrine components distinctly separated by the central fibrous band. The exocrine part showed a poorly-differentiated adenocarcinoma. The endocrine part was strongly immunoreactive to chromogranin, synaptophysin and glucagon. We reviewed the literature on pancreatic tumors with combined exocrine and endocrine features. A simple classification for this group of neoplasms is suggested, including five types: amphicrine, mixed, collision, solitary concomitant and multiple concomitant.

Anatomy of Pancreas in Mynah (Acridotheres tristis)

Saadatfar, Z. and Asadian, M. 2009. Anatomy of pancreas in mynah (Acridotheres tristis). J. Appl. Anim. Res., 36: 191–193. In the present study the histology of the exocrine and endocrine portions of pancreas in Mynah have been studied. Mynah s pancreas had three lobes. Acini were round to oval in shape with large granules. Ducts in exocrine part had simple to stratified cuboidal epithelium with muscular layer around and without any gland. In dorsal lobe, A islets were more than B islets and in ventral lobe, B islets were more than A islets. B islets were composed of B cells and D cells at the periphery. The structure of mynah's pancreas was similar to that of other avian species with minor differences.

PET und PET-CT maligner Tumoren des exokrinen Pankreas

Adenocarcinomas of the pancreas represent the majority (>95%) of all malignant pancreatic tumors. They are formed from malignant degeneration of the exocrine part of the pancreas. Cystic acinar tumors are much rarer and originate from secretion-producing parenchymal cells of the pancreas. Endocrine tumors of the pancreas will not be dealt with in this context.

Composite Carcinoma of the Stomach Associated with Sarcoid-Like Granulomas

Composite glandular/exocrine-endocrine carcinoma of the gastrointestinal tract is a special tumor type composed of common adenocarcinoma and the neuroendocrine component comprising at least one-third of the whole tumor area. These tumors are rare in the stomach and mostly published as case reports. We describe a further case of a 36-year-old man being unique in that it was associated with extensive formation of sarcoid-like granulomas. Tumor consisted of, predominantly poorly differentiated, intestinal-type adenocarcinoma and poorly differentiated neuroendocrine, small cell carcinoma. The adenocarcinomatous and neuroendocrine areas were separated, but closely juxtaposed with focal areas showing gradual transition from one to another. Perigastric lymph node metastases corresponded either to neuroendocrine or adenocarcinomatous component. On immunohistochemistry, the exocrine part was positive for cytokeratin 7, whereas superficial well-differentiated parts showed positivity with cytokeratin 20 as well. The neuroendocrine component was negative with those two types of cytokeratin. Both adenocarcinomatous and neuroendocrine tumor portions showed carcinoembryonic antigen (CEA) immunoexpression. Neuroendocrine markers (chromogranin A, synaptophysin and neuron-specific enolase) were diffusely positive in the neuroendocrine component, and found only in the scattered cells within the neoplastic glands of the adenocarcinoma. Entire gastric mucosa and all perigastric lymph nodes were extensively affected by noncaseating, sarcoid-like granulomas. The absence of any clinical manifestations combined with the negative results of chest radiograph and laboratory test for the serum angiotensin converting enzyme argued against the possibility of systemic sarcoidosis.

Autonomic Innervation of Pancreas in Egyptian Spiny Mouse (Acomys cahirinus, Desmarest)

The aim of the study was to obtain details of the morphology of the autonomic innervation of pancreas. Six adult Egyptian spiny mice (Acomys cahirinus, Desmarest) were studied for the presence and location of autonomic fibres and cells in the pancreas. The macromorphological investigations were performed using the thiocholine method adapted for this type of specimens. For processing tissues two histochemical techniques were used: thiocholine method on activity of AChE and the glyoxylic acid method for adrenergic structures. Cholinergic fibres and small autonomic ganglia were found among the secretory sections and along the pancreatic duct and both pancreaticoduodenal arteries, and its branches, reaching the Langerhans islets and forming around them a kind of net. From 24 to 40 AChE-positive ganglions in the whole exocrine part were observed. The highest density of cholinergic fibres was observed in the head of pancreas. Numerous adrenergic fibres that accompanied blood vessels as well as interlobular and intralobular ducts were found inside the exocrine parts of the pancreas. Neither adrenergic cells or adrenergic fibres were observed inside the pancreatic islets. Our results can be used in comparative anatomy studies of pancreas in mammals.

Cx36 makes channels coupling human pancreatic β-cells, and correlates with insulin expression

Previous studies have documented that the insulin-producing beta-cells of laboratory rodents are coupled by gap junction channels made solely of the connexin36 (Cx36) protein, and have shown that loss of this protein desynchronizes beta-cells, leading to secretory defects reminiscent of those observed in type 2 diabetes. Since human islets differ in several respects from those of laboratory rodents, we have now screened human pancreas, and islets isolated thereof, for expression of a variety of connexin genes, tested whether the cognate proteins form functional channels for islet cell exchanges, and assessed whether this expression changes with beta-cell function in islets of control and type 2 diabetics. Here, we show that (i) different connexin isoforms are differentially distributed in the exocrine and endocrine parts of the human pancreas; (ii) human islets express at the transcript level different connexin isoforms; (iii) the membrane of beta-cells harbors detectable levels of gap junctions made of Cx36; (iv) this protein is concentrated in lipid raft domains of the beta-cell membrane where it forms gap junctions; (v) Cx36 channels allow for the preferential exchange of cationic molecules between human beta-cells; (vi) the levels of Cx36 mRNA correlated with the expression of the insulin gene in the islets of both control and type 2 diabetics. The data show that Cx36 is a native protein of human pancreatic islets, which mediates the coupling of the insulin-producing beta-cells, and contributes to control beta-cell function by modulating gene expression.

A Modified Method using TRIzol® Reagent and Liquid Nitrogen Produces High-Quality RNA from Rat Pancreas

To establish an economical and reproducible method for the high-quality RNA extraction from pancreas, we isolated total RNA from rat pancreas with TRIzol reagent and liquid nitrogen. In the initial stage, we optimized three influential factors, the way to homogenize pancreas, the time to collect the pancreatic tissue from animals, and the weight of the pancreatic tissue in 1 ml of TRIzol reagent. The RNA quality was determined by detecting total RNA content and its absorbance at 260/280 nm wavelength, visualizing RNA in non-denatured agarose gel and performing RT-PCR of pancreas-specific genes. The A (260)/A (280) ratio of the total RNA extracted by grinding 20-30 mg of rat pancreatic tissue removed from the rats in liquid nitrogen within 1 min and then immersed in 1 ml of the TRIzol Reagent was 1.75-1.89, and the ratio of 28S/18S ribosomal RNA bands was more than 1.8. Furthermore, full length of Pdx1 open-reading frame was amplified with RNA extracted from the grinding group rather than from the conventional group. The RT-PCR products of pancreas-specific genes from both exocrine and endocrine parts of pancreas were successfully derived from the extracted RNA. The results suggested that we successfully provided an economical, fast, and reproducible method to obtain the high-quality and intact RNA from rat pancreas with TRIzol Reagent and liquid nitrogen.