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islet isolation

Maciej Sassek, Pawel A Kolodziejski, Mathias Z Strowski, Leszek Nogowski, Krzysztof W Nowak, Pawel Mackowiak
OBJECTIVES: Spexin is a peptide whose action is poorly understood but which is expressed in many tissues. This encouraged us to investigate the potential role of spexin in the regulation of pancreatic secretion. METHODS: Cells/islets were incubated with different concentrations of glucose and spexin to measure insulin secretion. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays and BrdU (5-bromo-2'-deoxyuridine) tests were performed to assess the viability and proliferation of pancreatic islets after spexin treatment...
June 16, 2018: Pancreas
Monal Sharma, Ranjithkumar Ravichandran, Sandhya Bansal, Ross M Bremner, Michael A Smith, T Mohanakumar
Exosomes are extracellular vesicles that express self-antigens (SAgs) and donor human leukocyte antigens. Tissue-specific exosomes can be detected in the circulation following lung, heart, kidney and islet cell transplantations. We collected serum samples from patients who had undergone lung (n=30), heart (n=8), or kidney (n=15) transplantations to isolate circulating exosomes. Exosome purity was analyzed by Western blot, using CD9 exosome-specific markers. Tissue-associated lung SAgs, collagen V (Col-V) and K-alpha 1 tubulin (Kα1T), heart SAgs, myosin and vimentin, and kidney SAgs, fibronectin and collagen IV (Col-IV), were identified using western blot...
June 14, 2018: Human Immunology
Christopher E Gibson, Kara E Boodhansingh, Changhong Li, Laura Conlin, Pan Chen, Susan A Becker, Tricia Bhatti, Vaneeta Bamba, N Scott Adzick, Diva D De Leon, Arupa Ganguly, Charles A Stanley
BACKGROUND: Previous case reports have suggested a possible association of congenital hyperinsulinism with Turner syndrome. OBJECTIVE: We examined the clinical and molecular features in girls with both congenital hyperinsulinism and Turner syndrome seen at The Children's Hospital of Philadelphia (CHOP) between 1974 and 2017. METHODS: Records of girls with hyperinsulinism and Turner syndrome were reviewed. Insulin secretion was studied in pancreatic islets and in mouse islets treated with an inhibitor of KDM6A, an X chromosome gene associated with hyperinsulinism in Kabuki syndrome...
June 14, 2018: Hormone Research in Pædiatrics
Kendall R McEachron, Melena D Bellin
PURPOSE OF REVIEW: We reviewed the current state of total pancreatectomy with islet autotransplantation (TPIAT) for chronic pancreatitis and recurrent acute pancreatitis (RAP). RECENT FINDINGS: An increasing number of centers in the United States and internationally are performing TPIAT. In selected cases, TPIAT may be performed partially or entirely laparoscopically. Islet isolation is usually performed at the same center as the total pancreatectomy surgery, but new data suggest that diabetes outcomes may be nearly as good when a remote center is used for islet isolation...
June 8, 2018: Current Opinion in Gastroenterology
Clarissa Hernandez Stephens, Kara S Orr, Anthony J Acton, Sarah A Tersey, Raghavendra G Mirmira, Robert V Considine, Sherry L Voytik-Harbin
Widespread use of pancreatic islet transplantation for treatment of type 1 diabetes (T1D) is currently limited by requirements for long-term immunosuppression, limited donor supply, and poor long-term engraftment and function. Upon isolation from their native microenvironment, islets undergo rapid apoptosis, which is further exacerbated by poor oxygen and nutrient supply following infusion into the portal vein. Identifying alternative strategies to restore critical microenvironmental cues, while maximizing islet health and function, are needed to advance this cellular therapy...
June 12, 2018: American Journal of Physiology. Endocrinology and Metabolism
Bo Hellman, Heléne Dansk, Eva Grapengiesser
Many cellular processes, including pulsatile release of insulin, are triggered by increase of cytoplasmic Ca2+ . This study examines how somatostatin affects glucose generation of cytoplasmic Ca2+ oscillations in mouse islets in absence and presence of tolbutamide blockade of the KATP channels. Ca2+ was measured with dual wavelength microflurometry in isolated islets loaded with the indicator Fura-2. Rise of glucose from 3 to 20 mM evoked introductory lowering of Ca2+ prolonged by activation of somatostatin receptors...
June 1, 2018: Cell Calcium
Syamsul A Arifin, Silvano Paternoster, Rodrigo Carlessi, Ilaria Casari, Jeppe Hvidtfeldt Ekberg, Tania Maffucci, Philip Newsholme, Mette M Rosenkilde, Marco Falasca
The gastrointestinal tract is increasingly viewed as critical in controlling glucose metabolism, because of its role in secreting multiple glucoregulatory hormones, such as glucagon like peptide-1 (GLP-1). Here we investigate the molecular pathways behind the GLP-1- and insulin-secreting capabilities of a novel GPR119 agonist, Oleoyl-lysophosphatidylinositol (Oleoyl-LPI). Oleoyl-LPI is the only LPI species able to potently stimulate the release of GLP-1 in vitro, from murine and human L-cells, and ex-vivo from murine colonic primary cell preparations...
June 5, 2018: Biochimica et Biophysica Acta
Nisha Vastani, Franziska Guenther, Clive Gentry, Amazon L Austin, Aileen J King, Stuart Bevan, David A Andersson
The mechanisms responsible for painful and insensate diabetic neuropathy are not completely understood. Here, we have investigated sensory neuropathy in the Ins2 +/Akita mouse, a hereditary model of diabetes. Akita mice become diabetic soon after weaning, and we show that this is accompanied by an impaired mechanical and thermal nociception and a significant loss of intraepidermal nerve fibers. Electrophysiological investigations of skin-nerve preparations identified a reduced rate of action potential discharge in Ins2 +/Akita mechanonociceptors compared to wildtype littermates, whereas the function of low threshold A-fibers was essentially intact...
June 6, 2018: Diabetes
Peter Daniel Rios, Michael Skoumal, Jeffrey Liu, R Youngblood, Ekaterina Kniazeva, Andrés J Garcia, Lonnie D Shea
Islet transplantation is a promising therapeutic option for Type 1 diabetes mellitus, yet the current delivery into the hepatic portal vasculature is limited by poor engraftment. Biomaterials have been employed as a means to promote engraftment and function at extrahepatic sites, with strategies being categorized as encapsulation or microporous scaffolds that can either isolate or integrate islets with the host tissue, respectively. While these approaches are typically studied separately using distinct material platforms, herein, we developed non-degradable polyethylene glycol (PEG)-based hydrogels for islet encapsulation or as microporous scaffolds for islet seeding in order to compare the initial engraftment and function of islets in syngeneic diabetic mice...
June 5, 2018: Biotechnology and Bioengineering
Tomoko Tanaka, Daibo Kojima, Toshiyuki Mera, Masahito Matsumoto, Yohichi Yasunami, Toshihiko Yanase
The shortage of donor islets is a significant obstacle for widespread clinical application of pancreatic islet transplantation. To investigate whether adipose tissue-derived mesenchymal stem cells (ADSCs) induce expansion of transplanted islets, we performed co-transplantation experiments in a mouse model. Streptozotosin (STZ)-induced diabetic mice transplanted with 50 syngeneic islets remained hyperglycemic. However, hyperglycemia was ameliorated gradually when 50 islets were co-transplanted with ADSCs but not separately grafted into the contralateral kidney...
May 2018: Heliyon
Elizabeth M Thompson, Jennifer L Sollinger, Emmanuel C Opara, Christopher A Adin
Currently, islet isolation is performed using harsh collagenases that cause nonspecific injury to both islets and exocrine tissue, negatively affecting the outcome of cell transplantation. We evaluated a novel islet isolation protocol utilizing high concentrations of glucose to cause selective osmotic shock (SOS). Islets have a membrane glucose transporter that allows adaptation to changes in glucose concentrations while exocrine tissue can be selectively destroyed by these osmolar shifts. Canine pancreata were obtained within 15 min after euthanasia from animals ( n = 6) euthanized for reasons unrelated to this study...
March 2018: Cell Transplantation
Veridiana Mota Moreira, Claudinéia Conationi da Silva Franco, Kelly Valério Prates, Rodrigo Mello Gomes, Ana Maria Praxedes de Moraes, Tatiane Aparecida Ribeiro, Isabela Peixoto Martins, Carina Previate, Audrei Pavanello, Camila Cristina Ianoni Matiusso, Douglas Lopes Almeida, Flávio Andrade Francisco, Ananda Malta, Laize Peron Tófolo, Sandra da Silva Silveira, Lucas Paulo Jacinto Saavedra, Katia Machado, Paulo Henrique Olivieri da Silva, Gabriel S Fabrício, Kesia Palma-Rigo, Helenir Medri de Souza, Flaviane de Fátima Silva, Giuliana Regina Biazi, Taís Susane Pereira, Elaine Vieira, Rosiane Aparecida Miranda, Júlio Cezar de Oliveira, Luiz Delmar da Costa Lima, Wilson Rinaldi, Maria Ida Ravanelli, Paulo Cezar de Freitas Mathias
Aerobic exercise training can improve insulin sensitivity in many tissues; however, the relationship among exercise, insulin, and cancer cell growth is unclear. We tested the hypothesis that aerobic exercise training begun during adolescence can attenuate Walker 256 tumor growth in adult rats and alter insulin secretion. Thirty-day-old male Wistar rats engaged in treadmill running for 8 weeks, 3 days/week, 44 min/day, at 55-65% VO2max until they were 90 days old (TC, Trained Control). An equivalently aged group was kept inactive during the same period (SC, Sedentary Control)...
2018: Frontiers in Physiology
Yumi Imai, Brian D Fink, Joseph A Promes, Chaitanya A Kulkarni, Robert J Kerns, William I Sivitz
We recently reported that mitoquinone (mitoQ, 500 μmol/L) added to drinking water of C57BL/6J mice attenuated weight gain and reduced oxidative stress when administered to high-fat (HF) fed mice. Here, we examined the effects of mitoQ administered to HF fed mice on pancreatic islet morphology, dynamics of insulin secretion, and islet mitochondrial metabolism. C57BL/6J mice were fed HF for 130 days while we administered vehicle (cyclodextrin [CD]) or mitoQ added to the drinking water at up to 500 μmol/L...
June 2018: Pharmacology Research & Perspectives
Liza Grapensparr, Gustaf Christoffersson, Per-Ola Carlsson
Pancreatic islets isolated for transplantation are disconnected from their vascular supply and need to establish a new functional network posttransplantation. Due to poor revascularization, prevailing hypoxia with correlating increased apoptosis rates in experimental studies can be observed for months posttransplantation. Endothelial progenitor cells (EPCs) are bone marrow-derived cells that promote neovascularization. The present study tested the hypothesis that EPCs, isolated from human umbilical cord blood, could be coated to human islet surfaces and be used to promote islet vascular engraftment...
January 1, 2018: Cell Transplantation
Lindor Gelin, Jiewen Li, Kathryn L Corbin, Ishrat Jahan, Craig S Nunemaker
Metformin is considered the first-line treatment for type 2 diabetes. While metformin primarily increases insulin sensitivity, evidence also suggests that metformin affects the activity of insulin-secreting pancreatic islets. This study was designed to systematically examine the direct effects of metformin by measuring insulin secretion and the kinetics of the calcium response to glucose stimulation in isolated mouse islets using varying concentrations (20  μ M, 200  μ M, and 1 mM) and durations (~1, 2, and 3 days) of metformin exposure...
2018: Journal of Diabetes Research
Andrew R Pepper, Antonio Bruni, A M James Shapiro
PURPOSE OF REVIEW: Clinical pancreatic islet transplantation has evolved into a routine means to restore glycemic control in patients with type 1 diabetes mellitus (T1DM) suffering from life-threatening hypoglycemia and severe glucose liability. This chapter examines the current progress in islet transplantation while outlining the remaining limitations preventing this life-altering therapy's application to the broader T1DM population. RECENT FINDINGS: Islet transplantation has recently been demonstrated to provide superior glycemic control with reduced glucose lability and hypoglycemic events compared with standard insulin therapy...
May 29, 2018: Current Opinion in Organ Transplantation
Madhura Panse, Oliver Kluth, Estela Lorza-Gil, Gabriele Kaiser, Eckhard Mühlbauer, Annette Schürmann, Hans-Ulrich Häring, Susanne Ullrich, Felicia Gerst
Glucose and palmitate synergistically stimulate insulin secretion, but chronically elevated they induce apoptotic β-cell death. The glucotoxic effect has been attributed, at least partly, to the upregulation of the oxidative stress marker thioredoxin interacting protein (TXNIP). Palmitate downregulates TXNIP expression, the functional significance of which is still under debate. This study examines the mechanism and consequence of palmitate-mediated TXNIP regulation in insulin secreting cells. Palmitate (600 μM) reduced TXNIP mRNA levels in isolated human and mouse islets independently of FFAR1/GPR40...
2018: PloS One
Zohreh Bagher, Seyed Kamran Kamrava, Rafieh Alizadeh, Mohammad Farhadi, Mahta Absalan, Masoumeh Falah, Faezeh Faghihi, Arash Zare-Sadegh, Ali Komeili
Cell transplantation is a potential therapeutic approach for repairing neuropathological and neurodegenerative disorders of central nervous system by replacing the degenerated cells with new ones. Among a variety of stem cell candidates to provide these new cells, olfactory ectomesenchymal stem cells (OE-MSCs) have attracted a great attention due to their neural crest origin, easy harvest, high proliferation, and autologous transplantation. Since there is no report on differentiation potential of these cells into motor neuron-like cells, we evaluated this potential using Real-time PCR, flowcytometry and immunocytochemistry after the treatment with differentiation cocktail containing retinoic acid and Sonic Hedgehog...
May 25, 2018: Journal of Chemical Neuroanatomy
Masaki Nagaya, Yuki Katsumata, Yoshikazu Arai, Ikuma Umeki, Kazuaki Nakano, Yuri Kasai, Koki Hasegawa, Kazutoshi Okamoto, Shiori Itazaki, Hitomi Matsunari, Masahito Watanabe, Kazuhiro Umeyama, Hiroshi Nagashima
BACKGROUND: The present study aimed to evaluate whether bioengineered mouse islet cell sheets can be used for the treatment of diabetes mellitus. METHODS: Isolated mouse pancreatic islets were dispersed, and cells were plated on temperature-responsive culture plates coated with iMatrix-551. On day 3 of culture, the sheets were detached from the plates and used for further analysis or transplantation. The following parameters were assessed: (1) morphology, (2) expression of β-cell-specific transcription factors and other islet-related proteins, (3) methylation level of the pancreatic duodenal homeobox-1 (Pdx-1) promoter, as determined by bisulfite sequencing, and (4) levels of serum glucose after transplantation of one or two islet cell sheets into the abdominal cavity of streptozotocin-induced diabetic severe combined immunodeficiency mice...
July 2018: Journal of Surgical Research
Charles A Chang, Kayla Murphy, Robert R Kane, Michael Lawrence, Bashoo Naziruddin
BACKGROUND: During the isolation process, pancreatic islets are exposed to an environment of sterile inflammation resulting in an upregulated inflammatory state prior to transplantation. Toll-like receptor 4 (TLR4) has been identified as a major mediator of sterile inflammation. Therefore, we sought to determine whether early TLR4 blockade would be effective in reducing the inflammatory burden in islets pretransplant. METHODS: Islets from C57BL/6 mice were treated with a TLR4 antagonist during the pancreatic ductal perfusion and digestion steps of the isolation process...
May 22, 2018: Transplantation
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