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1.
Lab Chip ; 24(6): 1557-1572, 2024 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-38205530

RESUMO

Enzymatically isolated pancreatic islets are the most commonly used ex vivo testbeds for diabetes research. Recently, precision-cut living slices of human pancreas are emerging as an exciting alternative because they maintain the complex architecture of the endocrine and exocrine tissues, and do not suffer from the mechanical and chemical stress of enzymatic isolation. We report a fluidic pancreatic SliceChip platform with dynamic environmental controls that generates a warm, oxygenated, and bubble-free fluidic pathway across singular immobilized slices with continuous deliver of fresh media and the ability to perform repeat serial perfusion assessments. A degasser ensures the system remains bubble-free while systemic pressurization with compressed oxygen ensures slice medium remains adequately oxygenated. Computational modeling of perfusion and oxygen dynamics within SliceChip guide the system's physiomimetic culture conditions. Maintenance of the physiological glucose dependent insulin secretion profile across repeat perfusion assessments of individual pancreatic slices kept under physiological oxygen levels demonstrated the culture capacity of our platform. Fluorescent images acquired every 4 hours of transgenic murine pancreatic slices were reliably stable and recoverable over a 5 day period due to the inclusion of a 3D-printed bioinert metallic anchor that maintained slice position within the SliceChip. Our slice on a chip platform has the potential to expand the useability of human pancreatic slices for diabetes pathogenesis and the development of new therapeutic approaches, while also enabling organotypic culture and assessment of other tissue slices such as brain and patient tumors.


Assuntos
Diabetes Mellitus , Ilhotas Pancreáticas , Humanos , Camundongos , Animais , Sistemas Microfisiológicos , Pâncreas , Ilhotas Pancreáticas/metabolismo , Oxigênio/metabolismo
2.
Diabetes ; 73(4): 554-564, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38266068

RESUMO

Assessment of pancreas cell type composition is crucial to the understanding of the genesis of diabetes. Current approaches use immunodetection of protein markers, for example, insulin as a marker of ß-cells. A major limitation of these methods is that protein content varies in physiological and pathological conditions, complicating the extrapolation to actual cell number. Here, we demonstrate the use of cell type-specific DNA methylation markers for determining the fraction of specific cell types in human islet and pancreas specimens. We identified genomic loci that are uniquely demethylated in specific pancreatic cell types and applied targeted PCR to assess the methylation status of these loci in tissue samples, enabling inference of cell type composition. In islet preparations, normalization of insulin secretion to ß-cell DNA revealed similar ß-cell function in pre-type 1 diabetes (T1D), T1D, and type 2 diabetes (T2D), which was significantly lower than in donors without diabetes. In histological pancreas specimens from recent-onset T1D, this assay showed ß-cell fraction within the normal range, suggesting a significant contribution of ß-cell dysfunction. In T2D pancreata, we observed increased α-cell fraction and normal ß-cell fraction. Methylation-based analysis provides an accurate molecular alternative to immune detection of cell types in the human pancreas, with utility in the interpretation of insulin secretion assays and the assessment of pancreas cell composition in health and disease.


Assuntos
Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Células Secretoras de Glucagon , Células Secretoras de Insulina , Ilhotas Pancreáticas , Humanos , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Ilhotas Pancreáticas/metabolismo , Metilação de DNA , Pâncreas/metabolismo , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Glucagon/metabolismo
3.
Cell Rep Methods ; 3(11): 100642, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37963464

RESUMO

To address the needs of the life sciences community and the pharmaceutical industry in pre-clinical drug development to both maintain and continuously assess tissue metabolism and function with simple and rapid systems, we improved on the initial BaroFuse to develop it into a fully functional, pumpless, scalable multi-channel fluidics instrument that continuously measures changes in oxygen consumption and other endpoints in response to test compounds. We and several other laboratories assessed it with a wide range of tissue types including retina, pancreatic islets, liver, and hypothalamus with both aqueous and gaseous test compounds. The setup time was less than an hour for all collaborating groups, and there was close agreement between data obtained from the different laboratories. This easy-to-use system reliably generates real-time metabolic and functional data from tissue and cells in response to test compounds that will address a critical need in basic and applied research.


Assuntos
Ilhotas Pancreáticas , Ilhotas Pancreáticas/metabolismo , Secreção de Insulina , Oxigênio/metabolismo , Consumo de Oxigênio , Gases/metabolismo
4.
Cell Rep ; 42(6): 112615, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37294632

RESUMO

Type 2 diabetes is characterized by insulin hypersecretion followed by reduced glucose-stimulated insulin secretion (GSIS). Here we show that acute stimulation of pancreatic islets with the insulin secretagogue dextrorphan (DXO) or glibenclamide enhances GSIS, whereas chronic treatment with high concentrations of these drugs reduce GSIS but protect islets from cell death. Bulk RNA sequencing of islets shows increased expression of genes for serine-linked mitochondrial one-carbon metabolism (OCM) after chronic, but not acute, stimulation. In chronically stimulated islets, more glucose is metabolized to serine than to citrate, and the mitochondrial ATP/ADP ratio decreases, whereas the NADPH/NADP+ ratio increases. Activating transcription factor-4 (Atf4) is required and sufficient to activate serine-linked mitochondrial OCM genes in islets, with gain- and loss-of-function experiments showing that Atf4 reduces GSIS and is required, but not sufficient, for full DXO-mediated islet protection. In sum, we identify a reversible metabolic pathway that provides islet protection at the expense of secretory function.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Ilhotas Pancreáticas , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Ilhotas Pancreáticas/metabolismo , Insulina/metabolismo , Glucose/metabolismo , Carbono/metabolismo , Células Secretoras de Insulina/metabolismo
5.
Cell Transplant ; 31: 9636897221086966, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35343264

RESUMO

Islet culture before clinical transplantation has been adopted by various centers, but its effect on the survival and function of islets relative to the culture conditions and media needs further assessment. Human islets were cultured or preserved under four different conditions and three media options. Parameters such as recovery, viability, function, islet damage, and gene expressions for markers of hypoxia, and inflammation were assessed after 48-h culture or preservation. Preservation of islets was performed at 4°C in Connaught's Medical Research Lab (CMRL) and University of Wisconsin (UW) media. Islets were cultured at 22°C, 37°C, and 37°C-22°C in CMRL and PRODO culture media. Islets preserved in UW solution had visually good morphology and exhibited higher recovery with less islet damage compared with the rest of the groups, whereas islets preserved in CMRL at 4°C resulted in poor morphology, recovery, viability, and function compared with the rest of the treatment conditions. Culture at 22°C and 37°C demonstrated an increase in the expression of inflammatory and hypoxia-related genes. In conclusion, islets preserved at 4°C in UW solution showed the best overall outcomes after 48 h compared with islets cultured at 22°C, 37°C, or 37°C-22°C in PRODO. Advancement in islet culture media is warranted to reduce inflammatory gene activation and improve recovery of islets for transplantation.


Assuntos
Ilhotas Pancreáticas , Soluções para Preservação de Órgãos , Adenosina , Alopurinol , Glutationa , Humanos , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Rafinose
6.
Cell Death Dis ; 13(1): 67, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-35046383

RESUMO

Short-chain fatty acids (SCFAs) produced by the gut microbiota have been well demonstrated to improve metabolic homeostasis. However, the role of SCFAs in islet function remains controversial. In the present study, none of the sodium acetate, sodium propionate, and sodium butyrate (SB) displayed acute impacts on insulin secretion from rat islets, whereas long-term incubation of the three SCFAs significantly potentiated pancreatic ß cell function. RNA sequencing (RNA-seq) revealed an unusual transcriptome change in SB-treated rat islets, with the downregulation of insulin secretion pathway and ß cell identity genes, including Pdx1, MafA, NeuroD1, Gck, and Slc2a2. But these ß cell identity genes were not governed by the pan-HDAC inhibitor trichostatin A. Overlapping analysis of H3K27Ac ChIP-seq and RNA-seq showed that the inhibitory effect of SB on the expression of multiple ß cell identity genes was independent of H3K27Ac. SB treatment increased basal oxygen consumption rate (OCR), but attenuated glucose-stimulated OCR in rat islets, without altering the expressions of genes involved in glycolysis and tricarboxylic acid cycle. SB reduced the expression of Kcnj11 (encoding KATP channel) and elevated basal intracellular calcium concentration. On the other hand, SB elicited insulin gene expression in rat islets through increasing H3K18bu occupation in its promoter, without stimulating CREB phosphorylation. These findings indicate that SB potentiates islet function as a lipid molecule at the expense of compromised expression of islet ß cell identity genes.


Assuntos
Células Secretoras de Insulina , Ilhotas Pancreáticas , Animais , Ácido Butírico/farmacologia , Ácidos Graxos Voláteis/metabolismo , Glucose/metabolismo , Glucose/farmacologia , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ratos
7.
Ecotoxicol Environ Saf ; 201: 110802, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531573

RESUMO

Extended exposure to inorganic arsenic through contaminated drinking water has been linked with increased incidence of diabetes mellitus. The most common exposure occurs through the consumption of contaminated drinking water mainly through geogenic sources of inorganic arsenic. Epigenetic modifications are important mechanisms through which environmental pollutants could exert their toxic effects. Bisulfite sequencing polymerase chain reaction method followed by Sanger sequencing was performed for DNA methylation analysis. Our results showed that sodium arsenite treatment significantly reduced insulin secretion in pancreatic islets. It was revealed that the methylation of glucose transporter 2 (Glut2) gene was changed at two cytosine-phosphate-guanine (CpG) sites (-1743, -1734) in the promoter region of the sodium arsenite-treated group comparing to the control. No changes were observed in the methylation status of peroxisome proliferator-activated receptor-gamma (PPARγ), pancreatic and duodenal homeobox 1 (Pdx1) and insulin 2 (Ins2) CpG sites in the targeted regions. Measuring the gene expression level showed increase in Glut2 expression, while the expression of insulin (INS) and Pdx1 were significantly affected by sodium arsenite treatment. This study revealed that exposure to sodium arsenite changed the DNA methylation pattern of Glut2, a key transporter of glucose entry into the pancreatic beta cells (ß-cells). Our data suggested possible epigenetic-mediated toxicity mechanism for arsenite-induced ß-cells dysfunction. Further studies are needed to dissect the precise epigenetic modulatory activity of sodium arsenite that affect the biogenesis of insulin.


Assuntos
Arsenitos/toxicidade , Metilação de DNA/efeitos dos fármacos , Transportador de Glucose Tipo 2/genética , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Compostos de Sódio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Epigênese Genética/efeitos dos fármacos , Proteínas de Homeodomínio/genética , Técnicas In Vitro , Insulina/genética , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Regiões Promotoras Genéticas , Ratos , Ratos Wistar , Transativadores/genética
8.
Biomed Microdevices ; 21(4): 91, 2019 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-31686215

RESUMO

Transplantation of pancreatic islets is becoming a promising therapy for people with type I diabetes. In this study, we present a compact fluidic system that enables assessment of islet functionality ex vivo for efficient islet transplantation. The fluidic system includes a micromesh sheet-embedded chip. Islets can be loaded easily on the micromesh sheet and observed clearly by microscopy. Islets on the mesh sheet mainly remained in place during perfusion and did not get damaged by hydraulic pressure because of high porosity of the micromesh sheet. The fluidic system was assembled with a sample fraction chip of polydimethylsiloxane. The chip includes a channel and columns, both having surfaces that were super-hydrophilized so that solutions could flow smoothly within the chip by gravity. Using mouse pancreatic islets, a dynamic glucose-stimulated insulin secretion test was performed to examine the performance of the fluidic system. The system successfully analyzed levels and patterns of insulin secretion upon exposure of the islets to low- and high-glucose solutions in turns, thus demonstrating its capacity to assess islet functions more easily and cost-effectively.


Assuntos
Ilhotas Pancreáticas/fisiologia , Dispositivos Lab-On-A-Chip , Animais , Dimetilpolisiloxanos , Desenho de Equipamento , Glucose/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Camundongos , Nylons
9.
Methods Mol Biol ; 2029: 25-35, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31273731

RESUMO

Pancreatic ß-cells in the islets of Langerhans secrete insulin in response to the rise in glucose levels following food intake. The hypoglycemic action of insulin applies a strong evolutionary brake on ß-cell division. However, under some conditions ß-cells can be stimulated to enter cell cycle progression and divide, for example following exposure to increased glucose levels or during pregnancy. Here, a protocol is described for the isolation of rat adult islets of Langerhans, followed by culture of intact islets in Matrigel and measurement of ß-cell replication by the incorporation of ethynyldeoxyuridine (EdU). EdU positive cells are revealed by a click reaction, nuclei are visualized using a DNA-binding fluorophore (Hoechst 33342), and ß-cells are identified using immunofluorescence detection.


Assuntos
Células Secretoras de Insulina/citologia , Ilhotas Pancreáticas/citologia , Animais , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Células Cultivadas , Colágeno/farmacologia , Combinação de Medicamentos , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Feminino , Glucose/metabolismo , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Laminina/farmacologia , Gravidez , Proteoglicanas/farmacologia , Ratos , Ratos Wistar
10.
Arch. endocrinol. metab. (Online) ; 63(3): 222-227, May-June 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1011165

RESUMO

ABSTRACT Objective Type 2 diabetes (T2DM) is characterized by the progressive deterioration of pancreatic islet β-cell function over time and insulin resistance. Knowing more about the differences in pancreatic islet function in T2DM patients who have had diabetes for different lengths of time can help improve therapy for T2DM. Subjects and methods We conducted a cross-sectional study to compare islet β-cell function and insulin resistance in T2DM patients (n = 3,254) who had had diabetes for different lengths of time and those in normal controls (n = 794) using ANOVA and LSD analysis. Results We found that compared with that in normal controls, HOMA-β in T2DM patients with a history of diabetes of less than 1 year was lower (approximately 52% of that of normal controls, p = 0.003), while HOMA-IR in these patients was higher (approximately 50% of that of normal controls, p = 0.007). Compared with that in other diabetic patients, HOMA-β in patients with a history of diabetes of more than 30 years was the lowest. HOMA-IR in patients with a history of diabetes of between 20 and 30 years was lower than that in other diabetic patients (p < 0.05). Conclusions There were obvious decreases in HOMA-β and increases in HOMA-IR in T2DM patients with a history of diabetes of less than 1 year compared with those in normal controls. Therefore, early screening and intervention for T2DM might help improve islet function and delay the progression of diabetes.


Assuntos
Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Resistência à Insulina , Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Insulina/metabolismo , Homeostase/fisiologia , Fatores de Tempo , Glicemia/análise , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos Transversais , Ilhotas Pancreáticas/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Teste de Tolerância a Glucose , Modelos Biológicos
11.
Arch Endocrinol Metab ; 63(3): 222-227, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31066759

RESUMO

OBJECTIVE: Type 2 diabetes (T2DM) is characterized by the progressive deterioration of pancreatic islet ß-cell function over time and insulin resistance. Knowing more about the differences in pancreatic islet function in T2DM patients who have had diabetes for different lengths of time can help improve therapy for T2DM. SUBJECTS AND METHODS: We conducted a cross-sectional study to compare islet ß-cell function and insulin resistance in T2DM patients (n = 3,254) who had had diabetes for different lengths of time and those in normal controls (n = 794) using ANOVA and LSD analysis. RESULTS: We found that compared with that in normal controls, HOMA-ß in T2DM patients with a history of diabetes of less than 1 year was lower (approximately 52% of that of normal controls, p = 0.003), while HOMA-IR in these patients was higher (approximately 50% of that of normal controls, p = 0.007). Compared with that in other diabetic patients, HOMA-ß in patients with a history of diabetes of more than 30 years was the lowest. HOMA-IR in patients with a history of diabetes of between 20 and 30 years was lower than that in other diabetic patients (p < 0.05). CONCLUSIONS: There were obvious decreases in HOMA-ß and increases in HOMA-IR in T2DM patients with a history of diabetes of less than 1 year compared with those in normal controls. Therefore, early screening and intervention for T2DM might help improve islet function and delay the progression of diabetes.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Homeostase/fisiologia , Resistência à Insulina , Células Secretoras de Insulina/metabolismo , Adulto , Idoso , Glicemia/análise , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/fisiopatologia , Teste de Tolerância a Glucose , Humanos , Ilhotas Pancreáticas/metabolismo , Pessoa de Meia-Idade , Modelos Biológicos , Fatores de Tempo
12.
Methods Mol Biol ; 1916: 223-232, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30535699

RESUMO

The islets of Langerhans release vital hormones involved in the regulation of blood sugar and other aspects of metabolism. The islets are housed in diffuse clusters of cells within the exocrine pancreas and, therefore, purification of these cells for research or transplant purposes is a difficult undertaking. Here, a detailed protocol is presented for purification of islets from rat pancreas using limited collagenase digestion and step gradient centrifugation techniques. In addition, a method for assessing islet viability is presented using perifusion under both basal and stimulatory glucose conditions, with measurement of the hormone released using an immunoassay for insulin.


Assuntos
Separação Celular/métodos , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/ultraestrutura , Pâncreas/metabolismo , Animais , Glucose/metabolismo , Humanos , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Pâncreas/patologia , Ratos
13.
Sci Rep ; 8(1): 11487, 2018 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-30065302

RESUMO

Magnetoliposomes (MLs) were synthesized and tested for longitudinal monitoring of transplanted pancreatic islets using magnetic resonance imaging (MRI) in rat models. The rat insulinoma cell line INS-1E and isolated pancreatic islets from outbred and inbred rats were used to optimize labeling conditions in vitro. Strong MRI contrast was generated by islets exposed to 50 µg Fe/ml for 24 hours without any increased cell death, loss of function or other signs of toxicity. In vivo experiments showed that pancreatic islets (50-1000 units) labeled with MLs were detectable for up to 6 weeks post-transplantation in the kidney subcapsular space. Islets were also monitored for two weeks following transplantation through the portal vein of the liver. Hereby, islets labeled with MLs and transplanted under the left kidney capsule were able to correct hyperglycemia and had stable MRI signals until nephrectomy. Interestingly, in vivo MRI of streptozotocin induced diabetic rats transplanted with allogeneic islets demonstrated loss of MRI contrast between 7-16 days, indicative of loss of islet structure. MLs used in this study were not only beneficial for monitoring the location of transplanted islets in vivo with high sensitivity but also reported on islet integrity and hereby indirectly on islet function and rejection.


Assuntos
Meios de Contraste/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Nanopartículas de Magnetita/administração & dosagem , Animais , Células Cultivadas , Diabetes Mellitus Experimental/induzido quimicamente , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Insulina/metabolismo , Transplante das Ilhotas Pancreáticas/métodos , Fígado/metabolismo , Fígado/patologia , Estudos Longitudinais , Imageamento por Ressonância Magnética/métodos , Veia Porta/metabolismo , Veia Porta/patologia , Ratos , Ratos Endogâmicos Lew , Ratos Wistar , Estreptozocina/farmacologia
14.
BMC Vet Res ; 13(1): 264, 2017 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-28830425

RESUMO

BACKGROUND: Canine diabetes is a strikingly prevalent and growing disease, and yet the standard treatment of a twice-daily insulin injection is both cumbersome to pet owners and only moderately effective. Islet transplantation has been performed with repeated success in canine research models, but has unfortunately not been made available to companion animals. Standard protocols for islet isolation, developed primarily for human islet transplantation, include beating-heart organ donation, vascular perfusion of preservation solutions, specialized equipment. Unfortunately, these processes are prohibitively complex and expensive for veterinary use. The aim of the study was to develop a simplified approach for isolating canine islets that is compatible with the financial and logistical restrictions inherent to veterinary medicine for the purpose of translating islet transplantation to a clinical treatment for canine diabetes. RESULTS: Here, we describe simplified strategies for isolating quality islets from deceased canine donors without vascular preservation and with up to 90 min of cold ischemia time. An average of more than 1500 islet equivalents per kg of donor bodyweight was obtained with a purity of 70% (N = 6 animals). Islets were 95% viable and responsive to glucose stimulation for a week. We found that processing only the body and tail of the pancreas increased isolation efficiency without sacrificing islet total yield. Islet yield per gram of tissue increased from 773 to 1868 islet equivalents when the head of the pancreas was discarded (N = 3/group). CONCLUSIONS: In summary, this study resulted in the development of an efficient and readily accessible method for obtaining viable and functional canine islets from deceased donors. These strategies provide an ethical means for obtaining donor islets.


Assuntos
Separação Celular/veterinária , Cães , Ilhotas Pancreáticas/citologia , Animais , Separação Celular/economia , Separação Celular/métodos , Sobrevivência Celular , Feminino , Glucose/farmacologia , Heparina , Insulina/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Transplante das Ilhotas Pancreáticas/veterinária , Masculino , Soluções para Preservação de Órgãos , Cloreto de Sódio , Técnicas de Cultura de Tecidos , Obtenção de Tecidos e Órgãos
15.
Diabetes ; 66(5): 1286-1292, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28246291

RESUMO

[11C]5-hydroxy-tryptophan ([11C]5-HTP) positron emission tomography of the pancreas has been shown to be a surrogate imaging biomarker of pancreatic islet mass. The change in islet mass in different stages of type 2 diabetes (T2D) as measured by noninvasive imaging is currently unknown. Here, we describe a cross-sectional study where subjects at different stages of T2D development with expected stratification of pancreatic islet mass were examined in relation to individuals without diabetes. The primary outcome was the [11C]5-HTP uptake and retention in pancreas, as a surrogate marker for the endogenous islet mass. We found that metabolic testing indicated a progressive loss of ß-cell function, but this was not mirrored by a decrease in [11C]5-HTP tracer accumulation in the pancreas. This provides evidence of retained islet mass despite decreased ß-cell function. The results herein indicate that ß-cell dedifferentiation, and not necessarily endocrine cell loss, constitutes a major cause of ß-cell failure in T2D.


Assuntos
5-Hidroxitriptofano , Radioisótopos de Carbono , Diabetes Mellitus Tipo 2/diagnóstico por imagem , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/diagnóstico por imagem , Idoso , Arginina , Glicemia/metabolismo , Peptídeo C/sangue , Estudos de Casos e Controles , Diferenciação Celular , Estudos Transversais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Progressão da Doença , Feminino , Glucose , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada
16.
PLoS One ; 11(12): e0168352, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28002466

RESUMO

BACKGROUND: Insulin secretion correlates inversely with insulin sensitivity, which may suggest the existence of a crosstalk between peripheral organs and pancreas. Such interaction might be mediated through glucose oxidation that may drive the release of circulating factors with action on insulin secretion. AIM: To evaluate the association between whole-body carbohydrate oxidation and circulating factors with insulin secretion to consecutive oral glucose loading in non-diabetic individuals. METHODS: Carbohydrate oxidation was measured after an overnight fast and for 6 hours after two 3-h apart 75-g oral glucose tolerance tests (OGTT) in 53 participants (24/29 males/females; 34±9 y; 27±4 kg/m2). Insulin secretion was estimated by deconvolution of serum C-peptide concentration, ß cell function by mathematical modelling and insulin sensitivity from an OGTT. Circulating lactate, free-fatty acids (FFA) and candidate chemokines were assessed before and after OGTT. The effect of recombinant RANTES (regulated on activation, normal T cell expressed and secreted) and IL8 (interleukin 8) on insulin secretion from isolated mice islets was also measured. RESULTS: Carbohydrate oxidation assessed over the 6-h period did not relate with insulin secretion (r = -0.11; p = 0.45) or ß cell function indexes. Circulating lactate and FFA showed no association with 6-h insulin secretion. Circulating chemokines concentration increased upon oral glucose stimulation. Insulin secretion associated with plasma IL6 (r = 0.35; p<0.05), RANTES (r = 0.30; p<0.05) and IL8 (r = 0.41; p<0.05) determined at 60 min OGTT. IL8 was independently associated with in vivo insulin secretion; however, it did not affect in vitro insulin secretion. CONCLUSION: Whole-body carbohydrate oxidation appears to have no influence on insulin secretion or putative circulating mediators. IL8 may be a potential factor influencing insulin secretion.


Assuntos
Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Adulto , Animais , Peptídeo C/sangue , Quimiocina CCL5/sangue , Quimiocina CCL5/genética , Quimiocina CCL5/metabolismo , Quimiocinas/sangue , Exercício Físico , Ácidos Graxos não Esterificados/sangue , Feminino , Glucose/metabolismo , Teste de Tolerância a Glucose , Voluntários Saudáveis , Humanos , Técnicas In Vitro , Secreção de Insulina , Interleucina-6/sangue , Interleucina-8/sangue , Interleucina-8/genética , Interleucina-8/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ácido Láctico/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologia
17.
EBioMedicine ; 8: 60-71, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27428419

RESUMO

Taste signals and nutrient stimuli sensed by the gastrointestinal tract are transmitted to the brain to regulate feeding behavior and energy homeostasis. This system is referred to as the gut-brain axis. Here we show that both brush cells and type II taste cells are eliminated in the gastrointestinal tract of transcription factor Skn-1 knockout (KO) mice. Despite unaltered food intake, Skn-1 KO mice have reduced body weight with lower body fat due to increased energy expenditure. In this model, 24-h urinary excretion of catecholamines was significantly elevated, accompanied by increased fatty acid ß-oxidation and fuel dissipation in skeletal muscle and impaired insulin secretion driven by glucose. These results suggest the existence of brain-mediated energy homeostatic pathways originating from brush cells and type II taste cells in the gastrointestinal tract and ending in peripheral tissues, including the adrenal glands. The discovery of food-derived factors that regulate these cells may open new avenues the treatment of obesity and diabetes. RESEARCH CONTEXT: Taste signals and nutrient stimuli sensed by the gastrointestinal tract are transmitted to the brain to regulate feeding behavior and energy homeostasis along the gut-brain axis. We propose the concept that taste-receiving cells in the oral cavity and/or food-borne chemicals-receiving brush cells in the gut are involved in regulation of the body weight and adiposity via the brain. The discovery of food-derived factors that regulate these cells may open new avenues for the treatment of obesity and diabetes.


Assuntos
Encéfalo/metabolismo , Catecolaminas/metabolismo , Metabolismo Energético/fisiologia , Trato Gastrointestinal/metabolismo , Obesidade/prevenção & controle , Fatores de Transcrição de Octâmero/genética , Gordura Abdominal/metabolismo , Glândulas Suprarrenais/metabolismo , Animais , Catecolaminas/urina , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Dieta Hiperlipídica , Dosagem de Genes , Insulina/metabolismo , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Fatores de Transcrição de Octâmero/deficiência , Fatores de Transcrição de Octâmero/metabolismo , Regulação para Cima
18.
Iran Biomed J ; 20(1): 18-25, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26459400

RESUMO

BACKGROUND: Oral vanadyl sulfate (vanadium) induces normoglycemia, proliferates beta cells and prevents pancreatic islet atrophy in streptozotocin-induced diabetic rats. Soteriological method is used to quantitate the proliferative effects of vanadium on beta-cell numbers and islet volumes of normal and diabetic rats. METHODS: Adult male Sprague-Dawley rats were made diabetic with intravenous streptozotocin injection (40 mg/kg). Normal and diabetic rats were divided into four groups. While control normal and diabetic (CD) groups used water, vanadium-treated normal (VTN) and diabetic (VTD) groups used solutions containing vanadyl sulfate (0.5-1 mg/mL, VOSO4+5H2O). Tail blood samples were used to measure blood glucose (BG) and plasma insulin. Two months after treatment, rats were sacrificed, pancreata prepared, and stereology method was used to quantitatively evaluate total beta cell numbers (TBCN) and total islet volumes (TISVOL). RESULTS: Normoglycemia persisted in VTN with significantly decreased plasma insulin (0.19±0.08 vs. 0.97±0.27 ng/dL, P<0.002). The respective high BG (532±49 vs. 144±46 mg/dL, P<0.0001) and reduced plasma insulin (0.26±0.15 vs. 0.54±0.19 ng/dL, P<0.002) seen in CD were reversed in VTD during vanadium treatment or withdrawal. While the induction of diabetes, compared to their control, significantly decreased TISVOL (1.9±0.2 vs. 3.03±0.6 mm3, P<0.003) and TBCN (0.99±0.1 vs. 3.2±0.2 x 106, P<0.003), vanadium treatment significantly increased TISVOL (2.9±0.8 and 4.07±1.0 mm3, P<0.003) and TBCN (1.5±0.3 and 3.8±0.6 x 106, P<0.03). CONCLUSION: Two-month oral vanadium therapy in STZ-diabetic rats ameliorated hyperglycemia by partially restoring plasma insulin. This action was through proliferative actions of vanadium in preventing islet atrophy by increasing beta-cell numbers.


Assuntos
Proliferação de Células/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Vanádio/administração & dosagem , Administração Oral , Animais , Contagem de Células , Proliferação de Células/fisiologia , Células Cultivadas , Diabetes Mellitus Experimental/patologia , Insulina/sangue , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Ratos , Ratos Sprague-Dawley
19.
Rev. latinoam. enferm ; 23(2): 234-241, Feb-Apr/2015. tab, graf
Artigo em Inglês | LILACS, BDENF | ID: lil-747177

RESUMO

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. .


Assuntos
Animais , Masculino , Camundongos , Transplante das Ilhotas Pancreáticas , Fatores de Transcrição Forkhead/metabolismo , Adjuvante de Freund/imunologia , Adjuvante de Freund/farmacologia , Rejeição de Enxerto/imunologia , Imunoterapia , Interferon gama/metabolismo , /metabolismo , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Lipídeos/imunologia , Lipídeos/farmacologia , Camundongos Endogâmicos BALB C , Baço/efeitos dos fármacos , Baço/efeitos da radiação , Transplante Homólogo , Células Th1/imunologia , Células Th1/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
20.
Islets ; 6(2): e29221, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25483959

RESUMO

Regular exercise has been shown to improve many complications of Type 1 diabetes mellitus (T1DM) including enhanced glucose tolerance and increased cardiac function. While exercise training has been shown to increase insulin content in pancreatic islets of rats with T1DM, experimental models were severely hyperglycemic and not undergoing insulin treatment. Further, research to date has yet to determine how exercise training alters glucagon content in pancreatic islets. The purpose of the present investigation was to determine the impact of a 10-week aerobic training program on pancreatic islet composition in insulin-treated rats with T1DM. Second, it was determined whether the acute, exercise-mediated reduction in blood glucose experienced in rats with T1DM would become larger in magnitude following aerobic exercise training. Diabetes was induced in male Sprague-Dawley rats by multiple low dose injections of streptozotocin (20mg/kg i.p.) and moderate intensity aerobic exercise training was performed on a motorized treadmill for one hour per day for a total of 10 weeks. Rats with T1DM demonstrated significantly less islet insulin, and significantly more islet glucagon hormone content compared with non-T1DM rats, which did not significantly change following aerobic training. The reduction in blood glucose in response to a single exercise bout was similar across 10 weeks of training. Results also support the view that different subpopulations of islets exist, as small islets (<50 µm diameter) had significantly more insulin and glucagon in rats with and without T1DM.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Tipo 1/sangue , Glucagon/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Condicionamento Físico Animal/fisiologia , Animais , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Transportador de Glucose Tipo 4/metabolismo , Insulina/uso terapêutico , Ilhotas Pancreáticas/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Receptor de Insulina/metabolismo
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