Pancreatic islet stereology: estimation of beta cells mass / Estereología de los islotes pancreáticos: estimación de la masa de células beta

Obesity and its comorbidities are becoming epidemic in the Western world. Beta cell mass estimation is an important indicator to track the progression of insulin resistance/type 2 diabetes, particularly in experimental studies, where it can be performed with stereological tools in an unbiased way. In this work, we present a simple protocol that can contribute to doing the practice of estimating the mass of beta cells more frequent and reproducible. As with any quantitative study, the necessary precautions regarding sampling and randomness must be respected.

La obesidad y sus comorbilidades se están convirtiendo en una epidemia en el mundo occidental. La estimación de la masa de células beta es un indicador importante para rastrear la progresión de la resistencia a la insulina/diabetes tipo 2, particularmente en estudios experimentales, donde se puede realizar con herramientas estereológicas de manera imparcial. En este trabajo presentamos un protocolo simple que puede contribuir a que la práctica de estimar la masa de células beta sea más frecuente y reproducible. Como en cualquier estudio cuantitativo, deben respetarse las precauciones necesarias con respecto al muestreo y la aleatoriedad.

Duodenal-jejunal bypass normalizes pancreatic islet proliferation rate and function but not hepatic steatosis in hypothalamic obese rats

Modifications in life-style and/or pharmacotherapies contribute to weight loss and ameliorate the metabolic profile of diet-induced obese humans and rodents. Since these strategies fail to treat hypothalamic obesity, we have assessed the possible mechanisms by which duodenal-jejunal bypass (DJB) surgery regulates hepatic lipid metabolism and the morphophysiology of pancreatic islets, in hypothalamic obese (HyO) rats. During the first 5 days of life, male Wistar rats received subcutaneous injections of monosodium glutamate (4 g/kg body weight, HyO group), or saline (CTL). At 90 days of age, HyO rats were randomly subjected to DJB (HyO DJB group) or sham surgery (HyO Sham group). HyO Sham rats were morbidly obese, insulin resistant, hypertriglyceridemic and displayed higher serum concentrations of non-esterified fatty acids (NEFA) and hepatic triglyceride (TG). These effects were associated with higher expressions of the lipogenic genes and fatty acid synthase (FASN) protein content in the liver. Furthermore, hepatic genes involved in β-oxidation and TG export were down-regulated in HyO rats. In addition, these rats exhibited hyperinsulinemia, β-cell hypersecretion, a higher percentage of islets and β-cell area/pancreas section, and enhanced nuclear content of Ki67 protein in islet-cells. At 2 months after DJB surgery, serum concentrations of TG and NEFA, but not hepatic TG accumulation and gene and protein expressions, were normalized in HyO rats. Insulin release and Ki67 positive cells were also normalized in HyO DJB islets. In conclusion, DJB decreased islet-cell proliferation, normalized insulinemia, and ameliorated insulin sensitivity and plasma lipid profile, independently of changes in hepatic metabolism.

Assessment of nursing care using indicators generated by software / Avaliação da assistência de enfermagem utilizando indicadores gerados por um software / Evaluación de la asistencia de enfermería utilizando indicadores generados por un software

OBJECTIVE: to analyze the efficacy of the Nursing Process in an Intensive Care Unit using indicators generated by software. METHOD: cross-sectional study using data collected for four months. RNs and students daily registered patients, took history (at admission), performed physical assessments, and established nursing diagnoses, nursing plans/prescriptions, and assessed care delivered to 17 patients using software. Indicators concerning the incidence and prevalence of nursing diagnoses, rate of effectiveness, risk diagnoses, and rate of effective prevention of complications were computed. RESULTS: the Risk for imbalanced body temperature was the most frequent diagnosis (23.53%), while the least frequent was Risk for constipation (0%). The Risk for Impaired skin integrity was prevalent in 100% of the patients, while Risk for acute confusion was the least prevalent (11.76%). Risk for constipation and Risk for impaired skin integrity obtained a rate of risk diagnostic effectiveness of 100%. The rate of effective prevention of acute confusion and falls was 100%. CONCLUSION: the efficacy of the Nursing Process using indicators was analyzed because these indicators reveal how nurses have identified patients' risks and conditions, and planned care in a systematized manner. .

OBJETIVO: analisar a eficácia do Processo de Enfermagem em uma Unidade de Terapia Intensiva, utilizando indicadores gerados por um software. MÉTODO: estudo transversal, cujos dados foram coletados durante quatro meses. Enfermeiros e acadêmicos realizaram, diariamente, cadastro e anamnese (na admissão), exame físico, diagnósticos de enfermagem, planejamento/prescrição de enfermagem e avaliação da assistência de 17 pacientes, utilizando um software. Calculou-se os indicadores incidência e prevalência de diagnósticos de enfermagem, taxa de efetividade diagnóstica de risco e taxa de efetividade na prevenção de complicações. RESULTADOS: o Risco de desequilíbrio na temperatura corporal foi o diagnóstico mais incidente (23,53%) e o menos incidente foi o Risco de constipação (0%). O Risco de integridade da pele prejudicada foi prevalente em 100% dos pacientes, enquanto o Risco de confusão aguda foi o menos prevalente (11,76%). Risco de constipação e Risco de integridade da pele prejudicada obtiveram taxa de efetividade diagnóstica de risco de 100%. A taxa de efetividade na prevenção de confusão aguda e de queda foi de 100%. CONCLUSÃO: analisou-se a eficácia do Processo de Enfermagem utilizando indicadores, pois retratam como o enfermeiro tem identificado os problemas e riscos do paciente, e planejado a assistência de forma sistematizada. .

OBJETIVO: analizar la eficacia del Proceso de Enfermería en una Unidad de Terapia Intensiva, utilizando indicadores generados por un software. MÉTODO: estudio transversal, cuyos datos fueron recolectados durante cuatro meses. Enfermeros y académicos realizaron, diariamente, registro y anamnesis (en la admisión), examen físico, diagnósticos de enfermería, planificación/prescripción de enfermería y evaluación de la asistencia en 17 pacientes, utilizando un software. Se calculó los indicadores incidencia y prevalencia de diagnósticos de enfermería, la tasa de efectividad diagnóstica de riesgo y la tasa de efectividad en la prevención de complicaciones. RESULTADOS: el Riesgo de desequilibrio en la temperatura corporal fue el diagnóstico más prevalente (23,53%) y el menos prevalente fue el Riesgo de constipación (0%). El Riesgo de integridad de la piel perjudicada fue prevalente en 100% de los pacientes, en cuanto el Riesgo de confusión aguda fue el menos prevalente (11,76%). El Riesgo de constipación y el Riesgo de integridad de la piel perjudicada obtuvieron una tasa de efectividad diagnóstica de riesgo de 100%. La tasa de efectividad en la prevención de confusión aguda y de caída fue de 100%. CONCLUSIÓN: se analizó la eficacia del Proceso de Enfermería utilizando indicadores, ya que retratan cómo el enfermero ha identificado los problemas y riesgos del paciente, y planificado la asistencia de forma sistematizada. .

Transplante de ilhotas pancreáticas humanas: revisão da literatura e implantação de um laboratório de isolamento de ilhotas pancreáticas / Human pancreatic islet transplantation: literature review and establishment of a pancreatic islet isolation laboratory

O diabetes melito tipo 1 (DM1) está associado ao desenvolvimento de complicações crônicas de elevada morbi-mortalidade em indivíduos jovens em idade produtiva. A terapia intensiva com insulina comprovadamente diminui o aparecimento das complicações crônicas da doença. Entretanto, essa terapia ainda está associada ao aumento da incidência de hipoglicemia. Em pacientes com “DM1 lábil”, os quais apresentam hipoglicemias graves sem sintomas de alerta, o transplante de ilhotas pancreáticas humanas é uma das melhores alternativas para restaurar a secreção de insulina e a percepção da hipoglicemia. Cerca de 80% dos pacientes que receberam transplante de ilhotas de mais de um doador, submetidos ao tratamento imunossupressor do protocolo de Edmonton, adquiriram independência de insulina após 1 ano do transplante. Porém, apenas 10% destes pacientes permaneceram livres de insulina após 5 anos. Entretanto, mesmo aqueles pacientes que necessitaram utilizar novamente insulina tiveram a normalização da homeostase glicêmica e da percepção da hipoglicemia, com prevenção da hipoglicemia grave. Sendo assim, o transplante de ilhotas é capaz de diminuir os níveis de glicose plasmática e HbA1c, reduzir a ocorrência de hipoglicemias graves e melhorar a qualidade de vida dos pacientes. O objetivo deste artigo foi fazer uma breve revisão da literatura sobre o isolamento e transplante de ilhotas pancreáticas humanas e relatar a implantação de um laboratório de isolamento de ilhotas humanas no Serviço de Endocrinologia do Hospital de Clínicas de Porto Alegre.

Type 1 diabetes mellitus (DM1) is associated with chronic complications of high morbidity and mortality in young adults in a productive age. Insulin therapy has proved to reduce the chronic complications of diabetes. However, this therapy is still associated to an increased incidence of hypoglycemia. In patients with “brittle DM1”, who have severe hypoglycemia without any symptoms (hypoglycemia unawareness), the pancreatic islet transplantation is one of the best alternatives for restoring insulin secretion and hypoglycemia perception. About 80% of the patients who received islet transplantation from more than one donor, on immunosuppressive treatment with the Edmonton’s protocol, maintained insulin independence 1 year after transplantation. Nevertheless, only 10% of these patients remained free of insulin after 5 years post-transplantation. However, even those patients who returned to insulin treatment had a normalization of the glucose homeostasis and hypoglycemia perception. Therefore, islet transplantation is able to diminish plasmatic glucose and HbA1c levels, to reduce the occurrence of severe hypoglycemia, and to improve the quality of life of the patients. The purpose of this paper is to briefly review islet isolation and transplantation process, and report the establishing of a human islet isolation laboratory in the Endocrine Service at Hospital de Clínicas de Porto Alegre.

Análise da expressão de TNF-alpha e CD133 no pâncreas após o transplante de células de medula óssea em camundongos hiperalimentados durante a lactação / Analysis of TNF-alpha and CD133 in pancreas after transplantation of bone marrow cells in overfeeding mice during lactation

Estudos populacionais, assim como modelos animais demonstram que além dos fatores já conhecidos, como uma dieta não balanceada e sedentarismo, insultos nutricionais no período gestacional ou durante a lactação, causam alterações metabólicas importantes que levam ao surgimento da obesidade, Diabetes Mellitus tipo 2 (DM2) e doenças cardiovasculares em longo prazo. Nesse estudo, analisamos o pâncreas de camundongos hiperalimentados adultos (150 dias) e camundongos hiperaliemntados jovens (21 e 28 dias). Os camundongos hiperalimentados de 21 dias receberam transplante de células mononucleares de medula óssea (CMO) e o resultado desse transplante foi observado aos 28 dias, quando os animais foram sacrificados. Nós investigamos: a apoptose das células beta através do fator pró-apoptótico Bax; a proliferação das células da ilhota pancreática através do antígeno nuclear de proliferação celular (PCNA); a expressão da citocina TNF-alpha, relacionado com a resistência à insulina em animais obesos e a expressão de células tronco CD133 com o objetivo de estudar a participação dessa célula na renovação da massa de células beta durante o estabelecimento da DM2. As análises das proteínas citadas no pâncreas foram realizadas através de microscopia de luz, microscopia confocal, microscopia eletrônica e Western blotting. O peso dos animais, a morfometria das ilhotas pancreáticas, bem como os níveis de glicose e insulina plasmáticos também foram determinados. Nossos resultados confirmaram que os camundongos hiperalimentados adultos apresentavam elevados níveis de glicose e insulina plasmática quando comparados ao grupo controle. Além disso, camundongos hiperalimentados adultos apresentaram aumento na expressão de Bax, indicando apoptose das células beta, maior expressão de TNF-alpha nas ilhotas pancreáticas, e presença de células CD133 nas ilhotas e ductos pancreáticos de camundongos hiperalimentados. Ao analisarmos os animais com 21 dias também observamos elevados níveis...

Population studies as well as animal models show that besides the factors already known as an unbalanced diet and sedentary lifestyle, nutritional insults during pregnancy of during lactation, causes important metabolic changes that lead to the emergence of obesity, type 2 diabetes mellitus (DM2) and cardiovascular diseases in long-term. In this study, we analyzed the pancreas of overfed adult mice (150 days) and young mice (21 and 28 days). At day 21, overfed mice were transplanted with bone marrow mononuclear cells (BMCs) and the results of this transplantation were observed at day 28. We investigated beta-cell apoptosis through pro-apoptotic factor Bax, the proliferation of pancreatic islet cells by proliferating cell nuclear antigen (PCNA), expression of TNF-alpha which has been linked to insulin resistance in obese animals and the expression of CD133 stem cells, in order to study the participation of this cell on the recovery of beta-cell mass during the establishment of DM2. The protein analysis, were performed using light microscopy, confocal microscopy, electron microscopy and Western blotting. The animals weight, morphology of pancreatic islets, as well as plasma levels of glucose and insulin were also determined. Our results confirmed that adult overfed mice had high levels of blood glucose and insulin when compared to control mice. Moreover, overfed adult mice showed an increased expression of Bax, indicating apoptosis of beta cells, also confirmed by transmission electron microscopy, increased expression of TNF-alpha in pancreatic islets when compared with the control group, and interestingly we observed the presence of CD133 cells in the pancreas of overfed mice. By analyzing the animals with 21 days, we also observed high levels of blood glucose and insulin in the overfed group, but we did not observe Bax expression at this lifetime. The expression of TNF-alpha was also increased in pancreas of overfed mice at day 21...

IIhotas pancreáticas humanas viáveis para o transplante através do aumento da massa de células e do imunoisolamento com microcápsulas biocompatíveis / Obtention of human pancreatic islets for transplantation through an increase in cell mass and an immunoisolation with biocompatible microcapsules

O transplante de ilhotas pancreáticas humanas representa uma estratégia promissora para a cura do diabetes mellitus tipo 1 (DM1) mas a aplicação a todos os pacientes diabéticos ainda é impraticável devido à limitada disponibilidade de ilhotas ou células β e à necessidade de utilização de drogas imunossupressoras pelo paciente transplantado. O tratamento com imunossupressores após o transplante de ilhotas pode ser abolido quando se realiza o microencapsulamento das ilhotas pancreáticas. Neste trabalho investigou-se um novo biomaterial, Biodritina (alginato/sulfato de condroitina) adequado ao microencapsulamento que gelifica na presença de íons de cálcio ou bário. A biocompatibilidade das microcápsulas tem sido avaliada segundo o grau de pureza do alginato utilizado na sua confecção. Amostras de alginato comercial purificado foram analisadas, comprovando-se a presença de impurezas (polifenóis, endotoxinas, proteínas) em níveis elevados, que impedem sua aplicação clínica. Optou-se, portanto pela utilização do alginato comercial ultrapurificado nos experimentos descritos neste trabalho. Das formulações de biomateriais avaliadas, as microcápsulas de bário-Biodritina apresentaram o melhor desempenho em testes de estabilidade físico-química...

Immunocytochemical detection of glucagon and insulin cells in endocrine pancreas and cyclic disparity of plasma glucose in the turtle Melanochelys trijuga.

The present investigation was carried out to know the seasonal variation in plasma glucose,insulin and glucagon cells during the reproductive cycle of untreated Melanochelys trijuga. Pancreatic endocrine cells were immunochemically localized.Insulin-immunoreactive (IR) cells occurred in groups of 3-20 and were in close apposition, while glucagon-IR cells were distributed individually between the exocrine pancreas or formed anastomosing cords where cells were not intimately attached. Whenever both IR cell types were present together forming an islet,insulin-IR cells formed clusters in the centre with glucagon-IR cells being scattered at the periphery. Glucagon-IR cells seemed to be secretory throughout the pancreas during the reproductive cycle,while insulin-IR cells were found to be pulsating in their secretion. Mean size of the islet was 1.306, 0.184 and 2.558 mm in the regenerative, reproductive and regressive periods,respectively. In general,insulin-IR cells measured 5.18 (mu)m and glucagon-IR cells 5.22 (mu)m in their longest axis. Invariably, glucagon-IR cells were more in number than insulin-IR cells. The fasting plasma glucose level was 69.97 mg% during the regenerative period, which increased to 97.96 mg% during the reproductive period,and reached a peak value of 113.52 mg% in the regressive period.

Avaliação morfológica e dos mecanismos de mobilização de Ca2+ pela glicose e acetilcolina em células pancreáticas humanas / Morphologic evaluation and Ca2+ mobilization by glicose and acetylcholine in human pancreatic cells

OBJETIVOS: Avaliar a morfologia das organelas e do citoesqueleto em células pancreáticas humanas cultivadas e a mobilização de Ca2+ em resposta à glicose e ACh por medidas fluorimétricas. MATERIAL E MÉTODOS: As células foram semeadas em lamínulas, fixadas e marcadas com uma combinação de fluoróforos: o núcleo foi corado com DAPI e as mitocôndrias, com Mytotracker Red. Foram utilizados faloidina e anticorpos secundários conjugados com Alexa Fluor verde e vermelho fluorescentes (488 e 594) para identificar proteína actina F e receptor muscarínico tipo M3, respectivamente. Para estudar a mobilização de Ca2+, as células foram incubadas com fura-2/AM. RESULTADOS: As células pancreáticas humanas apresentaram morfologia preservada com grande quantidade de mitocôndrias. Na região de maior densidade celular, evidenciou-se as pseudo-ilhotas e os receptores muscarínicos M3. Por meio da elevação da [Ca2+]c, devido à ação da glicose e ACh, mostrou-se preservação da capacidade responsiva a esses estímulos e foi dependente de concentração desses agonistas. A glicose promoveu uma resposta sustentada e a ACh induziu uma resposta bifásica. CONCLUSÃO: As células pancreáticas humanas cultivadas conservaram sua morfologia. A mobilização de Ca2+ em resposta à glicose e a ACh confirma a sua funcionalidade. Os receptores muscarínicos M3 estão presentes nessas células.

AIMS: The proposal of this study was to analyze morphology of the organelles and cytoskeleton in human pancreatic cells cultured and the mobilization of the cytosolic calcium ([Ca2+]c) in response to glucose and ACh by fluorimetry method. MATERIAL AND METHODS: The cells were plated on glass coverslips, fixed and stained with a combination of fluorophores: the nuclei were stained with DAPI and mitochondria with Mytotracker Red. It was used phalloidin and the secondary antibodies Alexa Fluor conjugated green and red-fluorescent (488 and 594) to identify the protein cell actin F and type M3 muscarinic receptor respectively. The cells also were loaded with fura-2/AM to study Ca2+ mobilization. RESULTS: The human pancreatic cells show characteristics morphologically preserved with great amount of mitochondria. In region major cell density was evidenced pseudo-islets and type M3 muscarinic receptors. Through increase of [Ca2+]c due to action of glucose and ACh were shown that the cellsÆ capacity to respond to these stimuli were conserved. The elevation of the [Ca2+]c depended on concentration by glucose-induced promoting sustained phase and ACh-induced a biphasic response. CONCLUSION: The morphologic characteristics of human pancreatic cells cultured were preserved. The Ca2+ mobilization in response to glucose and ACh confirmed its functionality. The expression of the M3 muscarinic receptors in human pancreatic cell cultured was demonstrated.

siRNA specific to Pdx-1 disturbed the formation of the islet in early zebrafish embryos / 华中科技大学学报（医学）（英德文版）

Pdx-1, an important transcription factor highlighting in the early pancreatic development, islet functions and pancreatic disorders, needs to be more investigated in zebrafish, and siRNA is still seldom applied in zebrafish embryo-related research. Our aim was to explore the role of pdx-1 in pancreatic development of zebrafish embryos by using siRNA approach. Microinjection, reverse transcriptase-PCR (RT-PCR), in situ hybridization and immunofluorescent staining were used in this research, and the morphology of the islet in normal zebrafish embryos, and in those treated with the siRNA specific to pdx-1 (siPDX-1) or siGFP was observed and compared. The expression of pdx-1 was detected in the stages of 1-cell, 2-cell, 4-cell, 8-cell, 16-cell, 16-hour by RT-PCT. The in situ hybridization and immunofluorescent staining results showed that siPDX-1 disturbed the formation of the islet in zebrafish embryos. Pdx-1 played multiple roles in maintaining the phenotype of the islet during embryogenesis in zebrafish.

Alotransplante de ilhotas de Langerhans no fígado de ratos submetidos a manipulação tímica com células não-parenquimatosas / Allogenic islet transplantation on the rat liver after allogenic nonparenchymal cells injection in the thymus

RACIONAL: A maior indicação do transplante de pâncreas ou de ilhotas de Langerhans é o diabetes mellitus do tipo I. O processo deve suprir as necessidades de insulina, mantendo os níveis glicêmicos dentro da normalidade OBJETIVOS: Estudar o alotransplante de ilhotas de Langerhans no fígado de ratos Lewis (RT1¹), tendo como doadores de ilhotas ratos Wistar (RT1u). No grupo controle (n = 8) injetava-se, no timo, solução de Hanks e no grupo de estudo(n = 8), células não-parenquimatosas hepáticas MATERIAL E MÉTODOS: No grupo controle com o método de separação e purificação das ilhotas de Langerhans obteve-se 3.637 ± 783,3 ilhotas com pureza de 85 ± 3,52 por cento. No grupo de estudo obteve-se 3.270 ± 770 ilhotas de Langerhans com pureza de 84,25 ± 2,76 por cento e com o método de isolamento e purificação das células não-parenquimatosas hepáticas obteve-se 2 x 10(6) células RESULTADOS: No grupo controle, o transplante de 3.637 ± 783,3 ilhotas de Langerhans no fígado, quase normalizou a glicemia que chegou a 17,95 ± 5,33 mmol/L no 2° dia do pós-operatório (diferença significante com relação ao pré-operatório). Do pós-operatório imediato até o 8° dia do pós-operatório a glicemia não se elevou significativamente, porém a partir do 10° dia do pós-operatório houve aumento significativo deste parâmetro, o que pode ser compatível com rejeição aguda do enxerto. No grupo de estudo, o transplante de 3.270 ± 770 ilhotas de Langerhans no fígado, quase normalizou a glicemia que chegou a 17,95 ± 5,33 mmol/L no 2° dias do pós-operatório (diferença significante com relação ao pré-operatório). Do 4° ao 10° pós-operatório a glicemia elevou-se significativamente, o que pode ser compatível com quadro de rejeição aguda do enxerto e certamente precoce CONCLUSÃO: A inoculação de células alogênicas apresentadoras de antígenos (células não-parenquimatosas hepáticas) no timo de ratos imunossuprimidos e diabéticos, antes...

BACKGROUD: The major indication for pancreas or islet transplantation is diabetes mellitus type I. This process has to supply the insulin necessity keeping glucose under control AIM: We studied allogenic islet transplantation on the rat liver, Wistar (RT1u) to Lewis (RT1¹) as a recipient. Control group (n = 8) and nonparenchymal cell group (n = 8) respectively with injection of Hanks solution and nonparenchymal cells in the thymus before islet transplantation. MATERIAL AND METHODS: With the method of isolation and purification of the islets we obtained both in the control group 3.637 ± 783,3 islets with purity of 85 ± 3,52 percent and nonparenchymal cell group 3.270 ± 770 islets with purity of 84,25 ± 2,76 percent. The nonparenchymal cells were retrieved from the liver and we obtained 2 x 106 cells. Diabetes was induced by i.v. streptozotocin RESULTS: Control group the transplantation of 3.637 ± 783,3 islets in the rat liver normalized glucose test, 7,21 ± 0,57 mmol/L in the 2nd postoperative day. Acute rejection came in the 6th postoperative day with significantly increase of glucose test in nonparenchymal cell group, the transplantation of 3.270 ± 770 islets in the rat liver, almost normalized the glucose test was 17,95 ± 5,33 mmol/L in the 2nd postoperative day. From the 4th postoperative day to 10th postoperative day. The glucose test increase significantly showing an early acute rejection CONCLUSION: The injection of nonparenchymal cells in the thymus before allogenic islet transplantation in the rat liver lead to an early acute rejection.

Histomorphological and quantitative immunohistochemical changes in the rat pancreas during aging

Although the endocrine pancreas is the purpose of several deep investigations, morphological data referred to the effect of aging on the gland are not homogeneous. The purpose of the current work was to analyze the changes occurring in the pancreas of aged rats, with especial reference to the islet cell populations. Six young (Y), old (O) and senescent (S) male Sprague-Dawley rats were used. The pancreas tails were processed for light microscopy and studied by means of routine stains as well as by immunohistochemical identification of insulin-, glucagon-, somatostatin-, and pancreatic polypeptide- secreting cells (Dako Envision System, DAB as chromogen). A progressive pancreatic histoarchitecture distortion was found among the aged animals. Even when the alterations were not uniformly observed, they appeared more evident and severe in the S group. The S rats showed significantly increased volume density and cell density of the B cell population, as well as larger number of islet profiles, when compared to O rats. A significant progressive increment of adipose tissue was also evident in aged animals. No abnormal changes were detected in the non.B cell populations of the different groups.

Comparative immunocytochemistry of isolated rat & monkey pancreatic islet cell types.

BACKGROUND & OBJECTIVES: Data on comparative distribution of the islet cell types in the Indian bonnet monkeys and rats are not available. The aim of the present study was to compare the arrangement of the three islet cell types in the native and in isolated rat and Indian bonnet monkey islets by immunocytochemistry. METHODS: Rat islets isolated by chopped tissue collagenase digestion method and islets of monkey isolated by intraductal collagenase digestion method were immunostained by streptavidin-biotin peroxidase method. RESULTS: Immunocytochemical staining of the isolated islets in both the species revealed the presence of three different cell types: insulin secreting B cells, glucagon secreting A cells and somatostatin secreting D cells. The arrangement of islet cell types in the rats and monkeys was similar to that of the intact islets of the native pancreas but were arranged in a definite pattern. In rats the A and D cells were peripherally arranged around the centrally located B cells. In monkeys the B cells occupied the majority of the periphery while the A and D cells were found mostly in the centre. INTERPRETATION & CONCLUSION: The findings of the present study showed that the arrangement of cell types in the islets was not affected by the isolation procedure. The difference in the arrangement of islet cell types in the two species may reflect special functional adaptations.

Epigallocatechin gallate, a constituent of green tea, suppresses cytokine-induced pancreatic beta-cell damage

Cytokines produced by immune cells infiltrating pancreatic islets have been implicated as one of the important mediators of beta-cell destruction in insulin-dependent diabetes mellitus. In this study, the protective effects of epigallocatechin gallate (EGCG) on cytokine-induced beta-cell destruction were investigated. EGCG effectively protected IL-1beta and IFN-g-mediated cytotoxicity in insulinoma cell line (RINm5F). EGCG induced a significant reduction in IL-1b and IFN-gamma-induced nitric oxide (NO) production and reduced levels of the inducible form of NO synthase (iNOS) mRNA and protein levels on RINm5F cells. The molecular mechanism by which EGCG inhibited iNOS gene expression appeared to involve the inhibition of NF-kB activation. These findings revealed EGCG as a possible therapeutic agent for the prevention of diabetes mellitus progression.

Inhibition of BETA2/NeuroD by Id2

Id (Inhibitor of Differentiation) proteins belong to a family of transcriptional modulators that are characterized by a helix loop helix (HLH) region but lack the basic amino acid domain. Id proteins are known to interact with basic helix-loop-helix (bHLH) transcription factors and function as their negative regulators. The negative role of Id proteins has been well demonstrated in muscle development and some in neuronal cells. In this study, we investigated the effect of Id on the function of BETA2/NeuroD, a bHLH transcription factor responsible for neuron and endocrine cell specific gene expression. cDNAs of several Id isoforms were isolated by yeast two-hybrid system using the bHLH domain of E47, a ubiquitous bHLH partner as a bait. Id proteins expressed in COS M6 cells, were found in both cytosolic and nuclear fractions. Electrophoretic mobility shift assay showed that coexpression of Id2 proteins inhibited BETA2/ NeuroD binding to its target sequence, E-box. Id2 inhibited E-box mediated gene expression in a dose dependent manner in BETA2/NeuroD expressing HIT cells. Id coexpressed with BETA2/NeuroD in HeLa cells, inhibited the stimulatory activity of BETA2/NeuroD. These results suggest that Id proteins may negatively regulate tissue specific gene expression induced by BETA2/NeuroD in neuroendocrine cells and the inhibitory role of Id proteins during differentiation may be conserved in various tissues.

Immunohistochemical Study of the Pancreatic Endocrine Cells in the BALB/c mice: An Unique Distributional Pattern of Glucagon

The regional distribution and relative frequency of insulin-, glucagon-, somatostatin- and pancreatic polypeptide (PP)-producing endocrine cells in the pancreas of BALB/c mouse were investigated by immunohistochemical method. The pancreas of mice was divided into two portions; pancreatic islets and exocrine portions, and pancreatic islets were further subdivided into two regions (central and peripheral regions) and the relative frequency and regional distribution of immunoreactive cells against insulin, glucagon, somatostatin and PP antisera were monitored. In the pancreatic islet portions, insulin-immunoreactive cells were located in the central regions and they were randomly dispersed in the whole pancreatic islets in some case of the small islets. Quite different from those of other mammals, glucagon-immunoreactive cells were dispersed throughout central to peripheral regions in case of large islets and in the smaller ones, most of these cells were situated in the peripheral regions. Somatostatin-immunoreactive cells were detected in the peripheral regions with various frequencies. Although some cells were demonstrated in the central regions of pancreatic islets, most of PP-immunoreactive cells were located in the peripheral regions. In the exocrine portions, all four types of immunoreactive cells were demonstrated in the BALB/c mouse. Some peculiar distributional patterns of pancreatic endocrine cells were found in BALB/c mouse, especially in case of glucagon-immunoreactive cells.

An immunohistochemical Study on the Pancreatic Endocrine Cells of the C57BL/6 Mouse

The regional distribution and relative frequency of the pancreatic endocrine cells in the C57BL/6 mouse were studied by immunohistochemical method using four types of specific mammalian antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreas of mouse could be divided into three portions; pancreatic islets, pancreatic duct and exocrine portions, and pancreatic islets were further subdivided into three regions (central, mantle and peripheral regions) according to their located types of immunoreactive cells and pancreatic duct portions were also subdivided into two regions (epithelial and connective tissue regions). In the pancreatic islet portions, although some cells were also demonstrated in the mantle regions, most of insulin-immunoreactive cells were located in the central regions and they were randomly dispersed in the whole pancreatic islets. Glucagon-immunoreactive cells were detected in the mantle and peripheral regions. Their relative frequencies in the peripheral regions were somewhat numerous than those of the mantle regions. Somatostatin-immunoreactive cells were detected in the mantle and peripheral regions. However, no PP-immunoreactive cells were demonstrated in the pancreatic islets of C57BL/6 mouse. In the pancreatic duct portions, rare glucagon-immunoreactive cells were situated in the epithelial regions. Cell clusters that consisted of glucagon- or somatostatin- immunoreactive cells were found in some case of connective tissue regions of pancreatic ducts. However, insulin- and PP-immunoreactive cells were not detected in the epithelial nor connective tissue regions. In the exocrine portions, all four types of immunoreactive cells except for PP cells were demonstrated in the C57BL/6 mouse. However, no PP-immunoreactive cells were demonstrated. In conclusion, regional distribution of endocrine cells in the pancreas of C57BL/6 mouse was similar to that of mammals, especially other rodents except for topographically different distribution of endocrine cells compared to that of other rodents.

Análise quantitativa das células das ilhotas pancreáticas de ratos pinealectomizados / Quantitative analysis of pancreatic islet cells of pinealectomised rats

Foi verificada a influência da glândula pineal em relação à análise quantitativa das células α, β e δ através de estudo imuno-histoquímico. Vinte ratos Wistar foram distribuídos em 2 grupos (grupo controle - grupo pinealectomizados). Os animais foram sacrificados 70 dias após a cirurgia. Amostras de pâncreas foram coradas com anticorpos monoclonais antiinsulina, antiglucagon e antisomatostatina. Foram contadas as células de cinco ilhotas de cada segmento. O número de células positivas para insulina nos ratos normais variou de 91 a 777 (312,5 ± 203,8) e nos pinealectomizados de 81 a 903 (524,4 ± 300,3); em relação ao glucagon variou nos normais de 83 a 326 (164,6 ± 95,4) e nos pinealectomizados de 95 a 287 (188,8 ± 78,4); em relação à somatostatina variou nos normais de 13 a 65 (35,4 ± 20,9) e nos pinealectomizados de 11 a 65 (29,7 ± 18,4). O número médio de células positivas para insulina nos animais pinealectomizados apresentou-se superior ao dos normais, mas essa superioridade não foi estatisticamente significante (p = 0,08). Estes resultados demonstram que a pineal parece exercer influência no pâncreas endócrino e corroboram estudos prévios.

The influence of the pineal gland on pancreatic islet with respect to a quantitative analysis of α, β and δ cells by immunohistochemistry was verified. Twenty Wistar rats was divided in two groups (control group - pinealectomysed group). The animals were sacrificed 70 days after surgery. Fragments of pancreas segments were stained with anti-insulin, anti-glucagon and antisomatostatin monoclonal antibodies. The cells of five islets were counted in each segments. The number of insulin-positive cells ranged from 91 to 777 (312,5 ± 203,8) in normal rats and from 81to 903 (524,4 ± 300,3) in pinealectomysed rats; glucagon-positive cells ranged from 83 to 326 - 164,6 ± 95,4 - (normals) and from 95 to 287 - 188,8 ± 78,4 - (pinealectomysed); somatostatin-positive cells ranged from 13 to 65 - 35,4 ± 20,9 - (normals) and from 11 to 65 - 29,7 ± 18,4 - (pinealectomysed). The mean number of insulin-positive cells was higher in pinealectomysed animals than in normal animals but not significantly (p = 0.08). These results indicate that the pineal gland seems to have an influence on endocrine pancreas and support previous studies.

Immunohistochemical localization of eight phospholipase C isozymes in pancreatic islets of the mouse

The possible involvement of phospholipase C (PLC) in the regulation of insulin secretion is not clearly understood and neither its isozymes expressed nor cellular localization in the pancreatic islets is known. By using specific monoclonal antibodies, we have investigated the expression and localization of eight different PLC isozymes, beta1, beta2, beta3, beta4, gamma1, gamma2, delta1, and delta2, in the pancreatic islets of adult mice. Immunohistochemical analysis carried out on paraffin embedded sections showed a distinct pattern of expression for each of the PLC isozymes. In the central part of the islets containing beta cells, a high level of beta4 and moderate levels of beta3 and gamma1 were expressed, whereas PLC-beta1 and -gamma1 were abundantly expressed in the exocrine pancreas. These results demonstrated the heterogeneity in expression of the phospholipase C isozymes in pancreatic islets. It is conceivable that these isozymes are coupled to different receptors and perform selective tasks in the regulation of insulin secretion for glucose homeostasis.

Comparative study of endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus (Siluridae) and Siniperca scherzeri (Centropomidae)

The regional distribution and relative frequency of some endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus Linne (Siluridae) and Siniperca scherzeri Steindachner (Centropomidae), which have similar feeding habits, were observed using specific antisera against insulin, glucagon, somatostatin and bovine pancreatic polypeptide (bovine PP) using the peroxidase antiperoxidase (PAP) method. Spherical to spindle shaped cells were demonstrated in the principal pancreatic islets in both species of teleost fishes. However, they were not detected in the exocrine portions nor the pancreatic ducts. Insulin-immunoreactive cells were located in the central regions of the principal pancreatic islets at high frequency in both species. Glucagonimmunoreactive cells were restricted to the peripheral regions of the principal pancreatic islets in both species. They formed a mantle zone in the peripheral regions of Silurus asotus with moderate frequency, and occupied a narrower mantle zone in Siniperca scherzeri with moderate frequency. In addition, glucagonimmunoreactive cell cores were also found in the peripheral zone of some principal pancreatic islets of Siniperca scherzeri. Somatostatin-immunoreactive cells were dispersed in the central zone of the principal pancreatic islets of Silurus asotus with moderate frequency, but were located in the peripheral regions with low frequency in Siniperca scherzeri. Bovine PPimmunoreactive cells were found in the peripheral region and the mantle zone of the principal pancreatic islets with low and rare frequency, respectively in both species. In conclusion, the regional distribution and relative frequency of endocrine cells in the principal pancreatic islets of Silurus asotus showed general patterns similar to those of other teleostean fishes. But, some speciesdependent distributional patterns and/or relative frequencies, particularly in glucagon-, somatostatin- and bovine PP-immunoreactive cells, were detected in the principal pancreatic islets of Siniperca scherzeri