Transthyretin Antisense Oligonucleotides Lower Circulating RBP4 Levels and Improve Insulin Sensitivity in Obese Mice

Circulating transthyretin (TTR) is a critical determinant of plasma retinol-binding protein 4 (RBP4) levels. Elevated RBP4 levels cause insulin resistance, and the lowering of RBP4 levels improves glucose homeostasis. Since lowering TTR levels increases renal clearance of RBP4, we determined whether decreasing TTR levels with antisense oligonucleotides (ASOs) improves glucose metabolism and insulin sensitivity in obesity. TTR-ASO treatment of mice with genetic or diet-induced obesity resulted in an 80–95% decrease in circulating levels of TTR and RBP4. Treatment with TTR-ASOs, but not control ASOs, decreased insulin levels by 30–60% and improved insulin sensitivity in ob/ob mice and high-fat diet–fed mice as early as after 2 weeks of treatment. The reduced insulin levels were sustained for up to 9 weeks of treatment and were associated with reduced adipose tissue inflammation. Body weight was not changed. TTR-ASO treatment decreased LDL cholesterol in high-fat diet–fed mice. The glucose infusion rate during a hyperinsulinemic-euglycemic clamp was increased by 50% in high-fat diet–fed mice treated with TTR-ASOs, demonstrating improved insulin sensitivity. This was also demonstrated by 20% greater inhibition of hepatic glucose production, a 45–60% increase of glucose uptake into skeletal and cardiac muscle, and a twofold increase in insulin signaling in muscle. These data show that decreasing circulating TTR levels or altering TTR-RBP4 binding could be a potential therapeutic approach for the treatment of type 2 diabetes.     

Exercise outcomes after pulmonary rehabilitation depend on the initial mechanism of exercise limitation among non-oxygen-dependent COPD patients

STUDY OBJECTIVES: Pulmonary rehabilitation (PR) that includes exercise training can improve exercise tolerance and quality of life for patients with COPD. However, the degree of benefit from PR is variable. We hypothesized that the exercise response to PR varies depending on the initial factors that limit exercise. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We retrospectively analyzed the change in exercise capacity after PR in 290 nonhypoxemic patients with COPD. We classified patients into the following subgroups based on the primary limitation seen on initial exercise testing: (1) ventilatory-limited (VL); (2) cardiovascular-limited (CVL); (3) mixed ventilatory/cardiovascular-limited (VLCVL); and (4) non-cardiopulmonary-limited (NL). We compared outcomes among subgroups. RESULTS: In the entire study population, PR led to increased timed walk distance (30.3%; p < 0.0001) and maximal oxygen consumption (VO2max) [84.8 mL/min; p < 0.0001]. Stepwise multiple regression selected age, ventilatory reserve at peak exercise, and exercise arterial oxygen pressure as individual predictors of improvement in VO2max. VO2max increased in the VL subgroup (30.4 mL/min; p = 0.008), the CVL subgroup (109.0 mL/min; p < 0.0001), the mixed VLCVL subgroup (61.3 mL/min; p < 0.0001), and NL subgroups (110.5 L/min; p < 0.0001). The improvement in VO2max was greater in the CVL subgroup than in the VL subgroup (p < 0.0001). Timed walk distance improved to a similar degree in all subgroups (26 to 36%). CONCLUSIONS: Patients with nonventilatory exercise limitations experience the greatest increase in VO2max after PR. However, even patients with severe ventilatory limitation can improve exercise tolerance with PR.     

Trimetazidine improves left ventricular function and quality of life in elderly patients with coronary artery disease.

AIM: Elderly patients have an increased incidence of ischaemic dilated cardiomyopathy often related to diffuse coronary artery disease. Trimetazidine protects ischaemic myocardium by improving the myocardial energy utilisation during myocardial ischaemia. Aim of the present study was to evaluate the effects of trimetazidine on left ventricular (LV) function in elderly patients with ischaemic heart disease and reduced LV function. METHODS: Forty seven elderly patients (40 males and 7 females, mean age 78+/-3 years) were randomised to receive, in addition to standard therapy, either trimetazidine or placebo and were evaluated by echocardiography at baseline and after 6 months. RESULTS: Trimetazidine and placebo had no effect on either blood pressure or heart rate (SBP 2+/-5 vs 4+/-6 mmHg, DBP -1+/-6 vs 3+/-4 mmHg, HR -3+/-7 vs 5+/-9 bpm, trimetazidine and placebo compared to baseline, respectively). At the end of the study patients randomised to trimetazidine showed a significant greater left ventricular function and smaller left ventricular diastolic and systolic diameters and volume indices compared to patients receiving placebo (LVEF: 34.4+/-2.3% vs 27+/-2.8%, p<0.0001; LVEDD: 58.6+/-1.9 mm vs 64+/-1.7 mm, p<0.0001; LVESD: 44.5+/-1.1 vs 50+/-0.8 mm, p<0.0001). A significant smaller wall motion score index was detected in trimetazidine-treated patients compared to those allocated to placebo (1.24+/-0.12 vs 1.45+/-0.19, p<0.01), the percentage change in LVEF compared to baseline was also significantly greater in trimetazidine-treated patients. Diastolic function significantly improved in the trimetazidine group while it remained unchanged in the placebo group. At follow-up evaluation, patients receiving trimetazidine showed a greater improvement in angina and NYHA class than patients allocated to placebo. Quality of life significantly improved in all patients treated with trimetazidine while remained unchanged in those allocated to placebo. CONCLUSION: In elderly patients with ischaemic cardiomyopathy trimetazidine in addition to standard medical therapy has a beneficial effect on LV systolic and diastolic function, and improves quality of life.     

Mutations of the hemophagocytic lymphohistiocytosis-associated gene UNC13D in a patient with systemic juvenile idiopathic arthritis

The clinical syndromes of hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are both characterized by dysregulated inflammation with prolonged fever, hepatosplenomegaly, coagulopathy, hematologic cytopenias, and evidence of hemophagocytosis in the bone marrow or liver. While HLH is either inherited or acquired, children with severe rheumatic diseases, most notably systemic juvenile idiopathic arthritis, are at risk for MAS. The phenotypic similarity between HLH and MAS raises the possibility that they share common pathogenetic mechanisms. Familial forms of HLH have been attributed to mutations in the genes encoding perforin (PRF1) and Munc13-4 (UNC13D), among others, and are characterized by defective cytotoxic lymphocyte function. While some patients with systemic JIA have decreased levels of perforin protein expression and natural killer (NK) cell function, mutations of HLH-associated genes in patients with systemic JIA have not been reported. We report the case of an 8-year-old girl with systemic JIA without MAS who was found to have compound heterozygous mutations of UNC13D and reduced NK cell cytotoxic function. This case broadens the range of clinical phenotypes attributable to UNC13D mutations and offers new insights into the etiology and pathogenesis of systemic JIA.     

Fc Receptors for IgG1 and IgG3 on Human Mononudear Cells -An Evaluation with Known Levels of Erythrocyte-Bound IgG

The Fc receptors on mononuclear cells were investigated by a rosette technique in which human erythrocytes were sensitized with a known number of molecules of anti-Rh antibodies (IgG1 or IgG3). The number of IgG molecules was quantitated by a radiometric antiglobulin test. The present quantitative evaluation reveals that (1) there is a logarithmic relationship between the proportion of rosettes and the amount of erythrocyte-bound immunoglobulin for both types of mononuclear cells, and for both subclasses; (2) similar percentage of rosettes can be obtained with fewer IgG3 than IgG1 molecules (about 1:4); (3) for a given number of erythrocyte-bound immunoglobulins a higher percentage of rosettes is observed with monocytes than with lymphocytes (ratios of about 3:1 for IgG1 and 5:1 for IgG3); (4) the minimum number of IgG3 molecules for adherence is 180-460 for monocytes, 520-1,300 for lymphocytes, whilst for IgG1 the numbers are 1,180-4,300 for monocytes and 3,400-14,200 for lymphocytes; (5) the minimum levels of sensitization by alloantibodies for adherence should be detectable by the antiglobulin test.