Diabetic β-Cells Can Achieve Self-Protection against Oxidative Stress through an Adaptive Up-Regulation of Their Antioxidant Defenses

Background Oxidative stress (OS), through excessive and/or chronic reactive oxygen species (ROS), is a mediator of diabetes-related damages in various tissues including pancreatic β-cells. Here, we have evaluated islet OS status and β-cell response to ROS using the GK/Par rat as a model of type 2 diabetes. Methodology/Principal Findings Localization of OS markers was performed on whole pancreases. Using islets isolated from 7-day-old or 2.5-month-old male GK/Par and Wistar control rats, 1) gene expression was analyzed by qRT-PCR; 2) insulin secretion rate was measured; 3) ROS accumulation and mitochondrial polarization were assessed by fluorescence methods; 4) antioxidant contents were quantified by HPLC. After diabetes onset, OS markers targeted mostly peri-islet vascular and inflammatory areas, and not islet cells. GK/Par islets revealed in fact protected against OS, because they maintained basal ROS accumulation similar or even lower than Wistar islets. Remarkably, GK/Par insulin secretion also exhibited strong resistance to the toxic effect of exogenous H2O2 or endogenous ROS exposure. Such adaptation was associated to both high glutathione content and overexpression (mRNA and/or protein levels) of a large set of genes encoding antioxidant proteins as well as UCP2. Finally, we showed that such a phenotype was not innate but spontaneously acquired after diabetes onset, as the result of an adaptive response to the diabetic environment. Conclusions The GK/Par model illustrates the effectiveness of adaptive response to OS by beta-cells to achieve self-tolerance. It remains to be determined to what extend such islet antioxidant defenses upregulation might contribute to GK/Par beta-cell secretory dysfunction

Islet Endothelial Activation and Oxidative Stress Gene Expression Is Reduced by IL-1Ra Treatment in the Type 2 Diabetic GK Rat

Inflammation followed by fibrosis is a component of islet dysfunction in both rodent and human type 2 diabetes. Because islet inflammation may originate from endothelial cells, we assessed the expression of selected genes involved in endothelial cell activation in islets from a spontaneous model of type 2 diabetes, the Goto-Kakizaki (GK) rat. We also examined islet endotheliuml/oxidative stress (OS)/inflammation-related gene expression, islet vascularization and fibrosis after treatment with the interleukin-1 (IL-1) receptor antagonist (IL-1Ra)

Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.

OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)

Two-year outcomes of patients with newly diagnosed atrial fibrillation: results from GARFIELD-AF.

AIMS: The relationship between outcomes and time after diagnosis for patients with non-valvular atrial fibrillation (NVAF) is poorly defined, especially beyond the first year. METHODS AND RESULTS: GARFIELD-AF is an ongoing, global observational study of adults with newly diagnosed NVAF. Two-year outcomes of 17 162 patients prospectively enrolled in GARFIELD-AF were analysed in light of baseline characteristics, risk profiles for stroke/systemic embolism (SE), and antithrombotic therapy. The mean (standard deviation) age was 69.8 (11.4) years, 43.8% were women, and the mean CHA2DS2-VASc score was 3.3 (1.6); 60.8% of patients were prescribed anticoagulant therapy with/without antiplatelet (AP) therapy, 27.4% AP monotherapy, and 11.8% no antithrombotic therapy. At 2-year follow-up, all-cause mortality, stroke/SE, and major bleeding had occurred at a rate (95% confidence interval) of 3.83 (3.62; 4.05), 1.25 (1.13; 1.38), and 0.70 (0.62; 0.81) per 100 person-years, respectively. Rates for all three major events were highest during the first 4 months. Congestive heart failure, acute coronary syndromes, sudden/unwitnessed death, malignancy, respiratory failure, and infection/sepsis accounted for 65% of all known causes of death and strokes for <10%. Anticoagulant treatment was associated with a 35% lower risk of death. CONCLUSION: The most frequent of the three major outcome measures was death, whose most common causes are not known to be significantly influenced by anticoagulation. This suggests that a more comprehensive approach to the management of NVAF may be needed to improve outcome. This could include, in addition to anticoagulation, interventions targeting modifiable, cause-specific risk factors for death. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Etude descriptive du profil lipidique de patients traités par tocilizumab (Roactemra®) pour une polyarthrite rhumatoïde

La polyarthrite rhumatoïde, maladie auto-immune multifactorielle évolutive touchant principalement les femmes, nécessite une prise en charge précoce en raison du risque de complications graves pouvant entraîner un handicap fonctionnel et de ce fait altérer la qualité de vie des patients. A l heure actuelle, les nouveaux traitements appelés également biothérapies permettent une action ciblée, plus spécifique, notamment sur les mécanismes inflammatoires. Parmi ces biothérapies, le tocilizumab (Roactemra®) est généralement prescrit en deuxième intention afin de mieux contrôler l activité de la maladie. Cependant il possède comme possible effet indésirable d induire des anomalies du profil lipidique en particulier une hypercholestérolémie pouvant aggraver la présence de facteurs de risque cardiovasculaires sachant que la polyarthrite rhumatoïde constitue également un facteur de risque. Cette thèse rapporte les résultats de suivi sur un an du profil lipidique chez des patients avec une polyarthrite rhumatoïde sévère justifiant un traitement par tocilizumab au sein du service de rhumatologie de Dijon, avec des résultats rassurants par rapport aux données de la littérature puisqu aucune modification significative n a été constatée, moyennant la mise en place de traitements hypolipémiant dans certains cas. Dans cette cohorte, ce traitement permet par ailleurs une épargne cortisonique conséquente qui est bénéfique chez des patients avec de nombreux facteurs de risque cardiovasculaires.DIJON-BU Médecine Pharmacie (212312103) / SudocSudocFranceF

Immunohistochemical characterization of monocytes-macrophages and dendritic cells involved in the initiation of the insulitis and β-cell destruction in NOD mice

This immunohistochemical study describes the infiltration pattern of monocytes-macrophages and dendritic cells during the development of insulitis and diabetes in the NOD mouse. A panel of monoclonal antibodies (MoAbs) was used to analyze pancreases of nondiabetic (glucosuria negative) male and female NOD mice at 3, 7, 10, and 17 weeks of age. BALB/c female mice 17- weeks-old, diabetic NOD female mice 20- to 30-weeks-old, and nondiabetic NOD male mice 22-weeks-old were used as controls. Three MoAbs (viz., ER-MP23, MOMA1, and BM8) were special and appeared to identify macrophage/dendritic cell subsets that either had a characteristic infiltration pattern in the initial phases of the autoimmune reaction before T-cell infiltration or were typical for the later β-cell destructive insulitis process. 1) Raised numbers of ER-MP23+ and MOMA-1+ dendritic cells/macrophages were characteristic for the initial phases of the NOD insulitis in 3-week-old mice. The cells were found in and near swollen para-insular vessels. In 7- week-old mice, these ER-MP23+ and MOMA-1+ cells had accumulated around the islets and were the first hematopoietic cells detectable at these spots. 2) From 7 weeks of age onward, BM8+ macrophages could be found in the para- and peri-insulitis processes. However, only in females were these BM8+ macrophages found to infiltrate into the islets. In lymphoid tissues, ER- MP23 predominantly reacts with macrophages/dendritic cells present in the subcapsular and interfollicular sinuses of lymph nodes and the T-cell zones of these lymph nodes. ER-MP23 also reacts with tissue macrophages/dendritic cells. MOMA-1 reacts with the marginal metallophilic macrophages of the spleen and with sinus macrophages of the lymph node. Both populations of cells are likely to be involved in antigen presentation in lymphoid tissues as well as in the NOD peri-insulitis. BM8 in lymphoid tissues predominantly reacts with the phagocytosing macrophages present in the red pulp of the spleen. Because β-cell destruction and glucosuria almost exclusively take place in NOD females, our findings suggest that BM8+ macrophage infiltration into the female islets is linked to a β-cell destructive process, either as a destructive type of infiltration or as an infiltration meant to remove the β-cell debris caused by another immune assault

Biological characteristics of 7-day-old or 2.5-month-old male Wistar and GK/Par rats.

<p>Glucose, insulin and α-tocopherol were determined in plasma. Glutathione redox state (% of reduced glutathione (GSH)) and GSH (Eq GSH) content were determined in red blood cells (RBC). Data are means±SEM. Wistar, <i>n</i> = 9–13; GK/Par, <i>n</i> = 7–9. *<i>p</i><0.05 <i>vs.</i> age-matched Wistar group.</p

Less reactive oxygen species (ROS) accumulated in diabetic GK/Par than Wistar islets.

<p>ROS generation was assessed as CM-H₂DCFDA fluorescence intensity (arbitrary units (AU)) normalized to total islet proteins in Wistar or GK/Par islets incubated at 2.8 (G2.8) or 16.7 mmol/l glucose (G16.7) (static incubation, 30 min), in the presence or the absence of blockers of the electron transfer chain complexes I (rotenone, 10 µmol/l) or III (antimycin A, 20 µmol/l), or the ROS scavenger (trolox, 1 mmol/l) (<i>A</i>). Insulin secretion values derived from experiments (<i>B</i>). Data are the means±SEM of 5–23 experiments in each group. *<i>p</i><0.05 <i>vs.</i> age-matched Wistar group; ⁺<i>p</i><0.05 <i>vs.</i> G2.8 or G16.7 for the same group; ^†<i>p</i><0.05 <i>vs.</i> G16.7 in the same experimental condition.</p