41 research outputs found
Recovery of Endogenous β-Cell Function in Nonhuman Primates After Chemical Diabetes Induction and Islet Transplantation
OBJECTIVE—To describe the ability of nonhuman primate endocrine pancreata to reestablish endogenous insulin production after chemical β-cell destruction
PAX4 preserves endoplasmic reticulum integrity preventing beta cell degeneration in a mouse model of type 1 diabetes mellitus
Mellado-Gil, José Manuel et al.[Aims/hypothesis]: A strategy to enhance pancreatic islet functional beta cell mass (BCM) while restraining inflammation, through the manipulation of molecular and cellular targets, would provide a means to counteract the deteriorating glycaemic control associated with diabetes mellitus. The aims of the current study were to investigate the therapeutic potential of such a target, the islet-enriched and diabetes-linked transcription factor paired box 4 (PAX4), to restrain experimental autoimmune diabetes (EAD) in the RIP-B7.1 mouse model background and to characterise putative cellular mechanisms associated with preserved BCM. [Methods]: Two groups of RIP-B7.1 mice were genetically engineered to: (1) conditionally express either PAX4 (BPTL) or its diabetes-linked mutant variant R129W (mutBPTL) using doxycycline (DOX); and (2) constitutively express luciferase in beta cells through the use of RIP. Mice were treated or not with DOX, and EAD was induced by immunisation with a murine preproinsulin II cDNA expression plasmid. The development of hyperglycaemia was monitored for up to 4 weeks following immunisation and alterations in the BCM were assessed weekly by non-invasive in vivo bioluminescence intensity (BLI). In parallel, BCM, islet cell proliferation and apoptosis were evaluated by immunocytochemistry. Alterations in PAX4- and PAX4R129W-mediated islet gene expression were investigated by microarray profiling. PAX4 preservation of endoplasmic reticulum (ER) homeostasis was assessed using thapsigargin, electron microscopy and intracellular calcium measurements. [Results]: PAX4 overexpression blunted EAD, whereas the diabetes-linked mutant variant PAX4R129W did not convey protection. PAX4-expressing islets exhibited reduced insulitis and decreased beta cell apoptosis, correlating with diminished DNA damage and increased islet cell proliferation. Microarray profiling revealed that PAX4 but not PAX4R129W targeted expression of genes implicated in cell cycle and ER homeostasis. Consistent with the latter, islets overexpressing PAX4 were protected against thapsigargin-mediated ER-stress-related apoptosis. Luminal swelling associated with ER stress induced by thapsigargin was rescued in PAX4-overexpressing beta cells, correlating with preserved cytosolic calcium oscillations in response to glucose. In contrast, RNA interference mediated repression of PAX4-sensitised MIN6 cells to thapsigargin cell death. [Conclusions/interpretation]: The coordinated regulation of distinct cellular pathways particularly related to ER homeostasis by PAX4 not achieved by the mutant variant PAX4R129W alleviates beta cell degeneration and protects against diabetes mellitus. The raw data for the RNA microarray described herein are accessible in the Gene Expression Omnibus database under accession number GSE62846.This work was funded by grants from the Consejeria de Salud, Fundacion Publica Andaluza Progreso y Salud, Junta de Andalucia (PI-0727-2010 to BRG and PI-0085-2013 to PIL), Consejeria de Economia, Innovacion y Ciencia (P10.CTS.6359 to BRG), Ministerio de Ciencia e Innovacion (BFU2013-42789-P to IQ) and the Ministerio de Economia y Competidividad, Instituto de Salud Carlos III co-funded by Fondos FEDER (PI10/00871 and PI13/00593 to BRG). NC-V is supported by a JDRF subsidy (17-2013-372 to BRG.). AM-M is a recipient of a Miguel Servet grant (CP14/00105) from the Instituto de Salud Carlos III co-funded by Fondos FEDER and EF-M is a recipient of a Juan de la Cierva Fellowship. PM is supported by Swiss National Science Foundation grant 310030-141162, and the European Union grant
IMIDIA, C2008-T7. BOB is supported by grants from the Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Republic of Singapore.Peer Reviewe
The effect of a novel curcumin derivative on pancreatic islet regeneration in experimental type-1 diabetes in rats (long term study)
Nonclinical analysis of the safety, pharmacodynamics, and pharmacokinetics of plasma‐derived human FXIII
Polymorphonuclear leucocyte elastase in Plasmodium falciparum malaria.
Sixty-one patients with falciparum malaria were studied prospectively to determine the plasma concentrations of the lysosomal proteinase, polymorphonuclear leucocyte elastase (PMN-elastase) and their relationship to disease severity. The patients were divided into 3 groups; severe (parasitaemia > 5%) or vital organ dysfunction (n = 23), moderate (parasitaemia 1%-5% without complications) (n = 15), and mild (parasitaemia < 1%) (n = 23). The mean plasma PMN-elastase level in 10 healthy Thai volunteers was 49.5 (SD = 21.6) ng/ml (range 33-65 ng/ml). Plasma PMN-elastase concentrations on admission were elevated (> 2 x SD above normal) in all patients with severe malaria and were above 100 ng/ml in 86.6% and 65% of the moderately severe and mild patients respectively. PMN-elastase levels during the first 3 hospital days were significantly higher in severe malaria compared with the other 2 groups (P = < 0.001-0.013). The levels decreased as the patients became afebrile and aparasitaemic. Admission plasma concentrations of PMN-elastase correlated directly with bilirubin (rs = 0.50, P < 0.001), serum glutamic oxalacetic transaminase (rs = 0.54, P0.001), parasite count (rs = 0.62, P < 0.001), blood urea nitrogen (rs = 0.54, P < 0.001) and inversely with antithrombin III activity (rs = 0.54, P < 0.001) and the platelet count (rs = 0.58, P < 0.001). Polymorphonuclear leucocyte activation may contribute to the pathogenesis of severe malaria
Activation of the coagulation cascade in falciparum malaria.
The incidence and progression of coagulation abnormalities were studied in 52 patients with acute falciparum malaria. The patients were prospectively divided into 3 groups; severe (parasitaemia greater than or equal to 5% or vital organ dysfunction), 12 patients; moderate (parasitaemia 1%- less than 5% without complications), 16 patients; and mild (parasitaemia less than 1%), 24 patients. No case died or developed clinical evidence of disseminated intravascular coagulation. Conventional indices of coagulation (prothrombin time, partial thromboplastin time, fibrinogen, fibrin degradation products) were usually within the normal range but reduced plasma concentrations of antithrombin III (AT-III) levels were noted in all groups, and the incidence was significantly higher in patients with severe and moderate malaria (83% and 81%) compared with the mild group (37%; P less than 0.005). Depletion of AT-III was associated with thrombocytopenia, decreased AT-III activity and elevated plasma concentrations of thrombin-antithrombin III complexes (P less than 0.01), confirming activation of the coagulation cascade and increased clotting factor consumption. AT-III levels returned to normal coincident with clinical improvement. Activation of coagulation is a common and sensitive measure of disease activity in acute falciparum malaria. It is not a specific feature, nor is there evidence to suggest it has a primary pathological role in severe infections