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islet isolation

Attilio Pingitore, Edward S Chambers, Thomas Hill, Inmaculada Ruz Maldonado, Bo Liu, Gavin Bewick, Douglas J Morrison, Tom Preston, Gareth A Wallis, Catriona Tedford, Ramón Castañera González, Guo Cai Huang, Pratik Choudhary, Gary Frost, Shanta J Persaud
AIMS: Diet-derived short chain fatty acids (SCFAs) improve glucose homeostasis in vivo, but the role of individual SCFAs and their mechanisms of action have not been defined. This study evaluated the effects of increasing colonic delivery of the SCFA propionate on β-cell function in humans and the direct effects of propionate on isolated human islets in vitro. MATERIALS AND METHODS: For 24 weeks human subjects ingested an inulin-propionate ester that delivers propionate to the colon...
October 20, 2016: Diabetes, Obesity & Metabolism
Kristen E Syring, Kayla A Boortz, James K Oeser, Alessandro Ustione, Kenneth A Platt, Melanie K Shadoan, Owen P McGuinness, David W Piston, David R Powell, Richard M O'Brien
Polymorphisms in the SLC30A8 gene, which encodes the ZnT8 zinc transporter, are associated with altered susceptibility to type 2 diabetes (T2D) and SLC30A8 haploinsufficiency is protective against the development of T2D in obese humans. SLC30A8 is predominantly expressed in pancreatic islet beta cells but surprisingly multiple knockout mouse studies have shown little effect of Slc30a8 deletion on glucose tolerance or glucose-stimulated insulin secretion (GSIS). Multiple other Slc30a isoforms are expressed at low levels in pancreatic islets...
October 18, 2016: Endocrinology
Jamal Mohammadi Ayenehdeh, Bahareh Niknam, Seyed Mahmoud Hashemi, Hossein Rahavi, Nima Rezaei, Masoud Soleimani, Nader Tajik
BACKGROUND: Islet transplantation could be an ideal alternative treatment to insulin therapy for type 1 diabetes Mellitus (T1DM). This clinical and experimental field requires a model that covers problems such as requiring a large number of functional and viable islets, the optimal transplantation site, and the prevention of islet dispersion. Hence, the methods of choice for isolation of functional islets and transplantation are crucial. METHODS: The present study has introduced an experimental model that overcomes some critical issues in islet transplantation, including in situ pancreas perfusion by digestive enzymes through common bile duct...
October 18, 2016: Iranian Biomedical Journal
Masayuki Shimoda, Shinichi Matsumoto
Allogeneic islet transplantation has become a viable option for the treatment of unstable type 1 diabetes; however, donor shortage and the necessity for immunosuppressive drugs are two major drawbacks of this treatment. Microencapsulated porcine islets can solve both of these drawbacks, and clinical trials have been conducted. Previous clinical trials demonstrated the safety and marginal efficacy of this treatment; therefore, it is necessary to improve its efficacy. The production of microencapsulated porcine islets consists of pancreas procurement, islet isolation, and microencapsulation...
2017: Methods in Molecular Biology
Kevin Enck, John Patrick McQuilling, Giuseppe Orlando, Riccardo Tamburrini, Sittadjody Sivanandane, Emmanuel C Opara
Islet transplantation (IT) has recently been shown to be a promising alternative to pancreas transplantation for reversing diabetes. IT requires the isolation of the islets from the pancreas, and these islets can be used to fabricate a bio-artificial pancreas. Enzymatic digestion is the current gold standard procedure for islet isolation but has lingering concerns. One such concern is that it has been shown to damage the islets due to nonselective tissue digestion. This chapter provides a detailed description of a nonenzymatic method that we are exploring in our lab as an alternative to current enzymatic digestion procedures for islet isolation from human and nonhuman pancreatic tissues...
2017: Methods in Molecular Biology
William F Kendall, Emmanuel C Opara
Since the discovery of insulin by Banting and Best in 1921, the prognosis and treatment options for individuals with diabetes have improved. The development of various insulin types, various oral agents, and insulin pumps have improved the available medical options for individuals afflicted with diabetes. The current need for frequent blood glucose monitoring imposed by multiple daily insulin injections, result in significant life-style challenges for in individuals afflicted with Type 1 diabetes (T1D). In contrast the use of surgical interventions, such as whole organ pancreas transplantation (PT) requires less-intensive glucose monitoring while the organ is viable...
2017: Methods in Molecular Biology
Anika Sahr, Carmen Wolke, Jonas Maczewsky, Peter Krippeit-Drews, Anja Tetzner, Gisela Drews, Simone Venz, Sarah Gürtler, Jens van den Brandt, Sabine Berg, Paula Döring, Frank Dombrowski, Thomas Walther, Uwe Lendeckel
The ACE2/angiotensin (Ang)-(1-7)/Mas axis of the renin-angiotensin system (RAS) often opposes the detrimental effects of the ACE/AngII/AT1 axis and has been associated with beneficial effects on glucose homeostasis, while underlying mechanisms are mostly unknown. Here, we investigate the effects of Ang-(1-7) and its receptor Mas on β-cell function. Isolated islets from Mas-deficient and wild-type mice were stimulated with Ang-(1-7) or its antagonists and effects on insulin secretion determined. Islets' cytoplasmic calcium and cAMP concentrations, mRNA amounts of Ins1, Ins2, Pdx1, and Mafa, and effects of inhibitors of cAMP downstream signaling were determined...
October 7, 2016: Endocrinology
Anna M Knapinska, Sabrina Amar, Zhong He, Sandro Matosevic, Claudia Zylberberg, Gregg B Fields
Cell isolation methods for therapeutic purposes have seen little advancement over the years. The original methods of stem cell and islet isolation using bacterial collagenases were developed in the early 1980s and are still used today. Bacterial collagenases are subject to autodegradation, and isolates obtained with these enzymes may be contaminated with endotoxins, reducing cell viability and contributing to toxicity in downstream applications. Here we describe a novel method for isolation of mesenchymal stem cells from adipose tissue (ADSC) utilizing recombinantly produced matrix metalloproteases (MMPs)...
November 2016: Enzyme and Microbial Technology
Valérie Bergeron, Julien Ghislain, Vincent Poitout
Free fatty acid receptor 1 (FFA1/GPR40) plays a key role in the potentiation of glucose-stimulated insulin secretion by fatty acids in pancreatic beta cells. We previously demonstrated that GPR40 signaling leads to cortical actin remodeling and potentiates the second phase of insulin secretion. In this study, we examined the role of p21 activated kinase 4 (PAK4), a known regulator of cytoskeletal dynamics, in GPR40-dependent potentiation of insulin secretion. The fatty acid oleate induced PAK4 phosphorylation in human islets, in isolated mouse islets and in the insulin secreting cell line INS832/13...
October 4, 2016: Islets
Leilei Yu, Huifeng Wang, Zhongxiu Guo, Fenghua Li, Hong Cui
Diabetes is a metabolic disease that results from impairment in insulin secretion. The present study aimed to investigate the potential role of NOM1 in the function of pancreatic islet β cells and insulin secretion. MIN6 cells isolated from mice were transfected with siRNA-NOM1 to assess the influence of NOM1 on the expression of the cell apoptosis-associated proteins, such as caspase-3. In addition, MIN6 cells were cultured in medium containing different glucose concentrations in order to assess the sensitivity of MIN6 cells to glucose...
October 2016: Experimental and Therapeutic Medicine
Y Maurice Morillon, Elizabeth Chase Lessey-Morillon, Matthew Clark, Rui Zhang, Bo Wang, Keith Burridge, Roland Tisch
The use of nondepleting Abs specific for CD4 and CD8 is an effective strategy to tolerize CD4(+) and CD8(+) T cells in a tissue-specific manner. We reported that coreceptor therapy reverses diabetes in new onset NOD mice. A striking feature of coreceptor-induced remission is the purging of T cells from the pancreatic lymph nodes (PLN) and islets of NOD mice. Evidence indicates that Abs binding to the coreceptors promotes T cell egress from these tissues. The present study examined how coreceptor therapy affects the migration of CD4(+) T cells residing in the PLN of NOD mice...
September 30, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Nancy El-Hossary, Hamdy Hassanein, Abdel Wahab El-Ghareeb, Hisham Issa
AIM: To evaluate the efficiency of mesenchymal stem cells isolated from Wharton's jelly (WJ-MSCs) through either the intravenous or intraperitoneal transplantations into streptozotocin (STZ)-induced diabetic rats as a therapy for type 1 diabetes mellitus (T1DM). METHODOLOGY: A rat model with STZ induction was established and the rats were divided into 3 groups: a tail vein injection group, an intraperitoneal injection group and a STZ control group. Following transplantation, blood glucose levels were monitored weekly then the pancreatic tissues were collected to examine the pancreatic islets by histopathology and morphometric studies...
September 21, 2016: Diabetes Research and Clinical Practice
Kevin Vivot, Valentine S Moullé, Bader Zarrouki, Caroline Tremblay, Arturo D Mancini, Hasna Maachi, Julien Ghislain, Vincent Poitout
OBJECTIVE: G protein-coupled receptor (GPCR) signaling regulates insulin secretion and pancreatic β cell-proliferation. While much knowledge has been gained regarding how GPCRs are activated in β cells, less is known about the mechanisms controlling their deactivation. In many cell types, termination of GPCR signaling is controlled by the family of Regulators of G-protein Signaling (RGS). RGS proteins are expressed in most eukaryotic cells and ensure a timely return to the GPCR inactive state upon removal of the stimulus...
October 2016: Molecular Metabolism
Hongxi Sun, Yu Li, Bei Sun, Ningning Hou, Juhong Yang, Miaoyan Zheng, Jie Xu, Jingyu Wang, Yi Zhang, Xianwei Zeng, Chunyan Shan, Bai Chang, Liming Chen, Baocheng Chang
BACKROUND: Type 2 diabetes has become a global epidemic disease. Atorvastatin has become a cornerstone in the prevention and treatment of atherosclerosis. However, increasing evidence showed that statins can dose-dependently increase the risk of diabetes mellitus. The mechanism is not clear. OBJECTIVE: The Ras complex pathway (Ras/Raf/extracellular signal-regulated kinase [ERK]/cAMP response element-binding protein [CREB]) is the major pathway that regulates the gene transcription...
September 2016: Medicine (Baltimore)
Rong Li, Jianhua Song, Wei Wu, Xinmou Wu, Min Su
In this study, we aim to explore the potential benefits of puerarin on metabolic function of liver fibrosis (LF) rat induced by carbon tetrachloride (CCl4), and to investigate with the underlying molecular mechanism targeted on liver and pancreas tissues. In methodology, The LF rats were prepared through intragastrically giving CCl4 twice each week (2ml/kg, v/w) for 8weeks, and dosed puerarin (20, 40mg/kg) were given three times each week via intraperitoneal injection. After being conducted with oral glucose tolerance test (OGTT), the blood samples of rat were harvested for biochemical tests, as well as the liver and pancreas were isolated for histological examination and biochemical assays...
September 24, 2016: Gene
Shiva Pathak, Shobha Regmi, Biki Gupta, Bijay K Poudel, Tung Thanh Pham, Jae-Ryong Kim, Pil-Hoon Park, Chul Soon Yong, Jong Oh Kim, Young Kyung Bae, Sang Kyoon Kim, Jee-Heon Jeong
Hypoxic or near-anoxic conditions that occur in the core of transplanted islets induce necrosis and apoptosis during the early stages after transplantation, primarily due to loss of vascularization during the isolation process. Moreover, secretion of various cytokines from pancreatic islets is detrimental to the viability of islet cells in vitro. In this study, we aimed to protect pancreatic islet cells against apoptosis by establishing a method for in situ delivery of curcumin to the pancreatic islets. Self-assembled heterospheroids composed of pancreatic islet cells and curcumin-loaded polymeric microspheres were prepared by the three-dimensional cell culture technique...
October 5, 2016: ACS Applied Materials & Interfaces
Khalil Leon Heileman, Jamal Daoud, Maryam Tabrizian
Dielectric spectroscopy could potentially be a powerful tool to monitor isolated human pancreatic islets for applications in diabetes therapy and research. Isolated intact human islets provide the most relevant means to understand the cellular and molecular mechanisms associated with diabetes. The advantages of dielectric spectroscopy for continuous islet monitoring are that it is a non-invasive, inexpensive and real-time technique. We have previously assessed the dielectric response of human islet samples during stimulation and differentiation...
September 16, 2016: Colloids and Surfaces. B, Biointerfaces
Jun Sung Moon, Udayakumar Karunakaran, Suma Elumalai, In-Kyu Lee, Hyoung Woo Lee, Yong-Woon Kim, Kyu Chang Won
AIM/HYPOTHESIS: Cluster determinant 36 (CD36), a fatty acid transporter, was reported to have a pivotal role in glucotoxicity-induced beta cell dysfunction. However, little is known about how glucotoxicity influences CD36 expression, and it is unknown whether this action can be counteracted by metformin. In the present study, we showed that metformin counteracts glucotoxicity by alleviating oxidative and endoplasmic reticulum (ER) stress-induced CD36 expression. METHODS: We used primary rat islets as well as INS-1 cells for 72h to 24h with 30mM glucose, respectively...
September 9, 2016: Journal of Diabetes and its Complications
Melena D Bellin, Pamela Clark, Sahar Usmani-Brown, Ty B Dunn, Gregory J Beilman, Srinath Chinnakotla, Timothy L Pruett, Peggy Ptacek, Bernhard J Hering, Zuoheng Wang, Thomas Gilmore, Joshua Wilhelm, James S Hodges, Antoinette Moran, Kevan C Herold
Beta cell death may occur both after islet isolation and during infusion back into recipients undergoing total pancreatectomy with islet autotransplantation (TPIAT) for chronic pancreatitis. We measured the novel beta cell death marker unmethylated insulin (INS) DNA in TPIAT recipients before and immediately after islet infusion (n=21), and again 90 days post-TPIAT concurrent with metabolic functional assessments (n=25). As expected, INS DNA decreased after pancreatectomy (p=0.0002). Following islet infusion, all TPIAT recipients had an elevated unmethylated INS DNA ratio in the first hours...
September 19, 2016: American Journal of Transplantation
Valérie Plaisance, Saška Brajkovic, Mathie Tenenbaum, Dimitri Favre, Hélène Ezanno, Amélie Bonnefond, Caroline Bonner, Valéry Gmyr, Julie Kerr-Conte, Benoit R Gauthier, Christian Widmann, Gérard Waeber, François Pattou, Philippe Froguel, Amar Abderrahmani
Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells...
2016: PloS One
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