We have recently developed a model of pancreatic islet transplantation into a decellularized pancreatic tail in rats. As the pancreatic skeletons completely lack endothelial cells, we investigated the effect of co-transplantation of mesenchymal stem cells and endothelial cells to promote revascularization. Decellularized matrix of the pancreatic tail was prepared by perfusion with Triton X-100, sodium dodecyl sulfate and DNase solution.
View Article and Find Full Text PDFNEUROD1 is a transcription factor that helps maintain a mature phenotype of pancreatic β cells. Disruption of Neurod1 during pancreatic development causes severe neonatal diabetes; however, the exact role of NEUROD1 in the differentiation programs of endocrine cells is unknown. Here, we report a crucial role of the NEUROD1 regulatory network in endocrine lineage commitment and differentiation.
View Article and Find Full Text PDFWe previously developed a deep learning-based web service (IsletNet) for an automated counting of isolated pancreatic islets. The neural network training is limited by the absent consensus on the ground truth annotations. Here, we present a platform (IsletSwipe) for an exchange of graphical opinions among experts to facilitate the consensus formation.
View Article and Find Full Text PDFBackground: Glucose homeostasis is dependent on functional pancreatic α and ß cells. The mechanisms underlying the generation and maturation of these endocrine cells remain unclear.
Results: We unravel the molecular mode of action of ISL1 in controlling α cell fate and the formation of functional ß cells in the pancreas.
Infusing pancreatic islets into the portal vein currently represents the preferred approach for islet transplantation, despite considerable loss of islet mass almost immediately after implantation. Therefore, approaches that obviate direct intravascular placement are urgently needed. A promising candidate for extrahepatic placement is the omentum.
View Article and Find Full Text PDFNovel Yb,Tb,Nd-doped GdF and NaGdF nanoparticles were synthesized by a coprecipitation method in ethylene glycol (EG) in the presence of the poly(4-styrenesulfonic acid--maleic anhydride) stabilizer. The particle size and morphology, crystal structure, and phase change were controlled by adjusting the PSSMA concentration and source of fluoride anions in the reaction. Doping of Yb, Tb, and Nd ions in the NaGdF host nanoparticles induced luminescence under ultraviolet and near-infrared excitation and high relaxivity in magnetic resonance (MR) imaging (MRI).
View Article and Find Full Text PDFBackground: Islet transplantation represents an established therapeutic option for people with type 1 diabetes who have hypoglycemia unawareness syndrome and frequent problematic hypoglycemic episodes when other methods comprising diabetes education and use of technological support fail. Because the current standard method of islet infusion into the liver has some limitations, novel approaches are under investigation.
Methods: We report our first results with 2 cases of islet transplantation into an omental pouch using a biocompatible plasma-fibrin gel.
Pancreatic islets transplantation is an established treatment method for type 1 diabetic patients with the hypoglycemia unawareness syndrome in whom a therapy with modern technologies fails. Islet transplantation is most commonly done using an interventional radiology method: a tissue suspension of pancreatic islets is applied into a branch of the portal vein through a percutaneously installed catheter. Although being minimally invasive unlike pancreas organ transplant, this method is associated with many technical difficulties.
View Article and Find Full Text PDFFolia Biol (Praha)
October 2021
Clostridial collagenases are essential biotechnological tissue dissociation agents owing to their ability to cleave different types of collagen. Standardization of collagenase-based protocols has been hampered by impurities in products manufactured from Clostridium histolyticum. To enhance the purification process, we produced recombinant collagenase classes G and H, taking advantage of the Escherichia coli expression system.
View Article and Find Full Text PDFDiabetes is a metabolic disease that involves the death or dysfunction of the insulin-secreting β cells in the pancreas. Consequently, most diabetes research is aimed at understanding the molecular and cellular bases of pancreatic development, islet formation, β-cell survival, and insulin secretion. Complex interactions of signaling pathways and transcription factor networks regulate the specification, growth, and differentiation of cell types in the developing pancreas.
View Article and Find Full Text PDFIn this paper, we present the design and implementation of a H/F volume coil for mouse body magnetic resonance (MR) imaging and spectroscopy using a high magnetic field (4.7 T). By changing the geometry of the coil rungs to include both nuclei for MR experiments, this innovative coil can be tuned over an extremely wide range of frequency.
View Article and Find Full Text PDFBackground: Transplantation of pancreatic islets into subcutaneous cavities in diabetic rats may be as or even more effective than transplantation into the portal vein. Identifying the optimal timing of the individual steps in this procedure is critical.
Methods: Macroporous scaffolds were placed in the subcutaneous tissue of diabetic male Lewis rats for 7 or 28 d and the healing of the tissue inside the scaffolds was monitored.
Purpose: The liver is the most widely used site for pancreatic islet transplantation. However, several site-specific limitations impair functional success, with instant blood-mediated inflammatory reaction being the most important. The aim of this study was to develop a preclinical model for placement of the islet graft into a highly vascularized omental flap using a fibrin gel.
View Article and Find Full Text PDFNADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islets (PIs) of β-cells through an as yet unknown mechanism. We found NADPH oxidase isoform 4 (NOX4) to be the main producer of cytosolic HO, which is essential for GSIS; an increase in ATP alone was insufficient for GSIS. The fast GSIS phase was absent from PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (though not from NOX2 knockout mice) and from NOX4-silenced or catalase-overexpressing INS-1E cells.
View Article and Find Full Text PDFParenteral nutrition (PN) is often associated with the deterioration of liver functions (PNALD). Omega-3 polyunsaturated fatty acids (PUFA) were reported to alleviate PNALD but the underlying mechanisms have not been fully unraveled yet. Using omics´ approach, we determined serum and liver lipidome, liver proteome, and liver bile acid profile as well as markers of inflammation and oxidative stress in rats administered either ω-6 PUFA based lipid emulsion (Intralipid) or ω-6/ω-3 PUFA blend (Intralipid/Omegaven) via the enteral or parenteral route.
View Article and Find Full Text PDFMultiple myeloma is, in most patients, an incurable cancer. Its precursors can be identified with routine tests setting the stage for early intervention to prevent active myeloma. We investigated the efficacy and safety of pembrolizumab, an antiprogrammed cell death 1 antibody, in smoldering myeloma patients with intermediate/high risk of progression to symptomatic myeloma.
View Article and Find Full Text PDFThree proteasome inhibitors have garnered regulatory approvals in various multiple myeloma settings; but drug resistance is an emerging challenge, prompting interest in blocking upstream components of the ubiquitin-proteasome pathway. One such attractive target is the E1 ubiquitin-activating enzyme (UAE); we therefore evaluated the activity of TAK-243, a novel and specific UAE inhibitor. TAK-243 potently suppressed myeloma cell line growth, induced apoptosis, and activated caspases while decreasing the abundance of ubiquitin-protein conjugates.
View Article and Find Full Text PDFBackground: Bortezomib with lenalidomide and dexamethasone (VRd) is a standard regimen for the front-line treatment of multiple myeloma. Panobinostat is approved in combination with bortezomib and dexamethasone in patients with myeloma who 'have been given at least two previous regimens including bortezomib and an immunomodulatory agent. We aimed to determine the maximum tolerated dose of a new regimen combining VRd with panobinostat in patients with newly diagnosed multiple myeloma.
View Article and Find Full Text PDFPurpose: Waldenström's macroglobulinemia is an incurable lymphoproliferative disorder driven by an L265P mutation in the myeloid differentiation primary response gene 88 (), which activates downstream NF-κB signaling through the Myddosome. As this pathway depends in part on activity of interleukin-1 receptor-associated kinases (IRAKs)-1 and -4, we sought to evaluate the potential of the IRAK1/4 inhibitor R191 in preclinical models.
Experimental Design: Patient-derived cell lines and primary samples were used in both and experiments to model Waldenström's macroglobulinemia and its response to IRAK1/4 inhibitors.
Bromodomain and extraterminal (BET) domain containing protein (BRD)-4 modulates the expression of oncogenes such as c-myc, and is a promising therapeutic target in diverse cancer types. We performed pre-clinical studies in myeloma models with bi-functional protein-targeting chimeric molecules (PROTACs) which target BRD4 and other BET family members for ubiquitination and proteasomal degradation. PROTACs potently reduced the viability of myeloma cell lines in a time-dependent and concentration-dependent manner associated with G/G arrest, reduced levels of CDKs 4 and 6, increased p21 levels, and induction of apoptosis.
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