Effect of pioglitazone on plasma ceramides in adults with metabolic syndrome.

BACKGROUND: Metabolic syndrome (MetS) appears closely linked with ceramide accumulation, inducing insulin resistance and toxicity to multiple cell types. Animal studies demonstrate that thiazolidinediones (TZDs) reduce ceramide concentrations in plasma and skeletal muscle and support lowering of ceramide levels as a potential mediator of TZDs' mechanism of action in reducing insulin resistance; however, studies in humans have yet to be reported. This study investigated the effects of pioglitazone therapy on plasma ceramides to understand the mechanism by which TZDs improve insulin resistance in MetS. METHODS: Thirty-seven subjects with MetS were studied in a single-centre, randomized, double-blind, placebo-controlled trial comparing pioglitazone to placebo. Data were collected at baseline and after 6 months of therapy. The primary endpoint was the change from baseline in plasma ceramide concentrations. RESULTS: Treatment with pioglitazone for 6 months, compared with placebo, significantly reduced multiple plasma ceramide concentrations: C18:0 (p = 0.001), C20:0 (p = 0.0004), C24 : 1 (p = 0.009), dihydroceramide C18 :0 (p = 0.005), dihydroceramide C24:1 (p = 0.004), lactosylceramide C16:0 (p = 0.02) and the hexosylceramides C16:0 (p = 0.0003), C18 : 0 (p = 0.00001), C22:0 (p = 0.00002) and C24:1 (p = 0.0006). Additionally, significant reductions were found when ceramides were grouped by species: ceramides (p = 0.03), dihydroceramides (p = 0.02), hexosylceramides (p = 0.00001) and lactosylceramides (p = 0.02). The total of all measured ceramides was also significantly reduced (p = 0.001). Following treatment with pioglitazone, the decrease in some ceramide species correlated negatively with the change in insulin sensitivity (dihydroceramide C16:0, r = -0.54; p = 0.02) and positively with total (lactosylceramide C24:0, r = 0.53; p = 0.02) and high molecular weight (lactosylceramide C24:0, r = 0.48; p = 0.05) adiponectin measurements; however, significant associations with changes in liver fat and glycemic control reduction were not found. CONCLUSIONS: Pioglitazone in individuals with MetS induces a potent decrease in plasma ceramides, and some of the changes correlate with changes in insulin resistance and adiponectin levels.

Outcomes of preoperative bridging therapy for patients undergoing surgery after coronary stent implantation: a weighted meta-analysis of 280 patients from eight studies.

BACKGROUND: Preoperative bridging with a glycoprotein IIb/IIIa inhibitor is often performed in patients with prior coronary stents undergoing surgery who require antiplatelet therapy discontinuation, but its safety and efficacy have received limited study. We performed a weighted meta-analysis of the outcomes in patients with coronary stents undergoing bridging with glycoprotein IIb/IIIa inhibitors prior to surgery. METHODS: We conducted a weighted meta-analysis of preoperative bridging studies published between 2002 and 2013 in patients with coronary stents undergoing surgery. Data on in-hospital mortality, stent thrombosis, bleeding, hemoglobin decrease, blood transfusion, time to hospital discharge and myocardial infarction were collected. RESULTS: A total of eight studies with 280 patients were included. Pooled estimates of outcomes were as follows: in-hospital mortality 3.5% (95% confidence interval [CI] 1.7-5.9%); stent thrombosis 1.3% (95% CI 0.3-3.0%); major bleeding 7.4% (95% CI 2.8-14.1%); any bleeding 20.6% (95% CI 4.8-43.2%); mean decrease in hemoglobin 2.8 g/dL (95% CI 2.5-3.0 g/dL); mean blood loss 271 mL (95% CI 211-311 mL); blood transfusion 13.9% (95% CI 1.0-38.2%); time to hospital discharge 5.9 days (95% CI 4.4-7.3 days); and myocardial infarction 1.6% (95% CI 0.3-3.6%). CONCLUSIONS: Preoperative bridging with a glycoprotein IIb/IIIa inhibitor in patients undergoing surgery after coronary stenting does not abolish the risk of perioperative stent thrombosis and may carry increased risk for bleeding. © 2014 Wiley Periodicals, Inc.

A human mutation in STAT3 promotes type 1 diabetes through a defect in CD8+ T cell tolerance.

Naturally occurring cases of monogenic type 1 diabetes (T1D) help establish direct mechanisms driving this complex autoimmune disease. A recently identified de novo germline gain-of-function (GOF) mutation in the transcriptional regulator STAT3 was found to cause neonatal T1D. We engineered a novel knock-in mouse incorporating this highly diabetogenic human STAT3 mutation (K392R) and found that these mice recapitulated the human autoimmune diabetes phenotype. Paired single-cell TCR and RNA sequencing revealed that STAT3-GOF drives proliferation and clonal expansion of effector CD8+ cells that resist terminal exhaustion. Single-cell ATAC-seq showed that these effector T cells are epigenetically distinct and have differential chromatin architecture induced by STAT3-GOF. Analysis of islet TCR clonotypes revealed a CD8+ cell reacting against known antigen IGRP, and STAT3-GOF in an IGRP-reactive TCR transgenic model demonstrated that STAT3-GOF intrinsic to CD8+ cells is sufficient to accelerate diabetes onset. Altogether, these findings reveal a diabetogenic CD8+ T cell response that is restrained in the presence of normal STAT3 activity and drives diabetes pathogenesis.

New Frontiers in the Treatment of Type 1 Diabetes.

Type 1 diabetes is an autoimmune disease caused by the immune-mediated destruction of pancreatic ß cells that results in lifelong absolute insulin deficiency. For nearly a century, insulin replacement has been the only therapy for most people living with this disease. Recent advances in technology and our understanding of ß cell development, glucose metabolism, and the underlying immune pathogenesis of the disease have led to innovative therapeutic and preventative approaches. A paradigm shift in immunotherapy development toward the targeting of islet-specific immune pathways involved in tolerance has driven the development of therapies that may allow for the prevention or reversal of this disease while avoiding toxicities associated with historical approaches that were broadly immunosuppressive. In this review, we discuss successes, failures, and emerging pharmacological therapies for type 1 diabetes that are changing how we approach this disease, from improving glycemic control to developing the "holy grail" of disease prevention.

Is autoimmunity the Achilles' heel of cancer immunotherapy?

The emergence of immuno-oncology as the first broadly successful strategy for metastatic cancer will require clinicians to integrate this new pillar of medicine with chemotherapy, radiation, and targeted small-molecule compounds. Of equal importance is gaining an understanding of the limitations and toxicities of immunotherapy. Immunotherapy was initially perceived to be a relatively less toxic approach to cancer treatment than other available therapies-and surely it is, when compared to those. However, as the use of immunotherapy becomes more common, especially as first- and second-line treatments, immunotoxicity and autoimmunity are emerging as the Achilles' heel of immunotherapy. In this Perspective, we discuss evidence that the occurrence of immunotoxicity bodes well for the patient, and describe mechanisms that might be related to the induction of autoimmunity. We then explore approaches to limit immunotoxicity, and discuss the future directions of research and reporting that are needed to diminish it.

Effect of Adding Liraglutide vs Placebo to a High-Dose lnsulin Regimen in Patients With Type 2 Diabetes: A Randomized Clinical Trial.

IMPORTANCE: An increasing number of patients with type 2 diabetes are treated with high doses of insulin. Such treatment is associated with weight gain, hypoglycemia, and high treatment burden. OBJECTIVE: To assess the effectiveness and safety of adding a glucagon-like peptide 1 receptor agonist to the treatment regimen of patients with type 2 diabetes requiring therapy with high-dose insulin. DESIGN, SETTING, AND PARTICIPANTS: This clinical trial was a double-blind, placebo-controlled, randomized (1:1) study with 6 months of follow-up, conducted from August 13, 2012, to February 9, 2015, at ambulatory clinics at the University of Texas Southwestern Medical Center and Parkland Hospital. Participants were 71 patients with uncontrolled type 2 diabetes (glycated hemoglobin level, 7.5%-11.0%) using more than 1.5 U/kg/d of insulin. INTERVENTIONS: Subcutaneous injection of liraglutide (1.8 mg/d) or matching placebo for 6 months. MAIN OUTCOMES AND MEASURES: The primary outcome was the change in glycated hemoglobin level. Secondary outcomes were changes in weight, hypoglycemia rate, insulin dosage, and quality-of-life measures. RESULTS: Among 71 patients, 45 (63%) were female. The mean (SD) age of patients was 54.2 (7.4) years, with a mean (SD) type 2 diabetes duration of 17.9 (8.4) years and a mean (SD) total daily dose of insulin of 247.0 (95.1) U. Ninety-three percent (66 of 71) of participants completed all scheduled visits. The glycated hemoglobin level improved from a mean (SD) of 9.0% (1.2%) to 7.9% (1.1%) in the liraglutide group (P < .001) and remained unchanged (8.9%) in the placebo group, with an estimated treatment difference of 0.9% (95% CI, -1.5 to -0.4) (P = .002). Weight decreased from a mean (SD) of 114.6 (21.4) kg to 113.6 (20.8) kg in the liraglutide group vs a mean (SD) increase from 116.1 (26.6) kg to 117.2 (27.2) kg in the placebo group, with a treatment difference of -2.3 kg (95% CI, -4.3 to -0.4 kg) (P = .02). The total daily dose of insulin decreased 11.5% (95% CI, -21.8% to -1.1%) in the liraglutide group (P = .20). The hypoglycemia rate was higher in the first month after initiation of liraglutide compared with placebo (2.30 vs 0.91 events per person-month, P = .01), while the overall hypoglycemia rate over the entire follow-up was similar between groups (P = .11). Glycemia control perception, satisfaction with insulin treatment, and willingness to continue insulin use improved more in the liraglutide group. CONCLUSIONS AND RELEVANCE: Liraglutide added to high-dose insulin therapy improved glycemic control, decreased body weight, and enhanced treatment satisfaction in this difficult-to-treat patient population with high-dose insulin requirements. Further studies are warranted to confirm these findings and evaluate the long-term risk and benefit of this treatment option. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01505673.

Mechanisms of Action of Liraglutide in Patients With Type 2 Diabetes Treated With High-Dose Insulin.

CONTEXT: The mechanisms of action of incretin mimetics in patients with long-standing type 2 diabetes (T2D) and high insulin requirements have not been studied. OBJECTIVE: To evaluate changes in ß-cell function, glucagon secretion, and fat distribution after addition of liraglutide to high-dose insulin. DESIGN: A single-center, randomized, double-blind, placebo-controlled trial. SETTING: University of Texas Southwestern and Parkland Memorial Hospital clinics. PATIENTS: Seventy-one patients with long-standing (median, 17 years) T2D requiring high-dose insulin treatment (>1.5 U/kg/d; average, 2.2 ± 0.9 U/kg/d). INTERVENTION: Patients were randomized to liraglutide 1.8 mg/d or matching placebo for 6 months. MAIN OUTCOME MEASURES: We measured changes in insulin and glucagon secretion using a 4-hour mixed-meal challenge test. Magnetic resonance-based techniques were used to estimate sc and visceral fat in the abdomen and ectopic fat in the liver and pancreas. RESULTS: Glycosylated hemoglobin improved significantly with liraglutide treatment, with an end-of-trial estimated treatment difference between groups of −0.9% (95% confidence interval, −1.5, −0.4%) (P = .002). Insulin secretion improved in the liraglutide group vs placebo, as measured by the area under the curve of C-peptide (P = .002) and the area under the curves ratio of C-peptide to glucose (P = .003). Insulin sensitivity (Matsuda index) and glucagon secretion did not change significantly between groups. Liver fat and sc fat decreased in the liraglutide group vs placebo (P = .0006 and P = .01, respectively), whereas neither visceral nor pancreatic fat changed significantly. CONCLUSIONS: Treatment with liraglutide significantly improved insulin secretion, even in patients with long-standing T2D requiring high-dose insulin treatment. Liraglutide also decreased liver and sc fat, but it did not alter glucagon secretion.