OBJECTIVE The aim of this study was to investigate tissue-specific effects of dapagliflozin on insulin sensitivity and liver and body fat in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS This randomized, double-blind, parallel group, placebo-controlled study recruited 32 patients with type 2 diabetes. Enrolled patients were to have HbA_1c 6.5–10.5% (48–91 mmol/mol) and ≥3 months of stable treatment with metformin, dipeptidyl peptidase 4 inhibitor, or their combination. Patients were randomized 1:1 to receive 10 mg dapagliflozin or placebo daily for 8 weeks. Before and after the intervention, tissue insulin sensitivity was measured using [¹⁸F]-fluorodeoxyglucose and positron emission tomography (PET) during hyperinsulinemic-euglycemic clamp. Liver proton density fat fraction (PDFF) and adipose tissue volumes were assessed using MRI, and blood biomarkers were analyzed. RESULTS After 8 weeks, glycemic control was improved by dapagliflozin (placebo-corrected change in HbA_1c −0.39%, P < 0.01), but whole-body glucose uptake was not increased (P = 0.90). Tissue-specific insulin-stimulated glucose uptake did not change in skeletal muscle, liver, myocardium, or white and brown adipose tissue, and endogenous glucose production remained unaffected. However, there were significant placebo-corrected decreases in liver PDFF (−3.74%, P < 0.01), liver volume (−0.10 L, P < 0.05), visceral adipose tissue volume (−0.35 L, P < 0.01), interleukin-6 (−1.87 pg/mL, P < 0.05), and N-terminal prohormone of brain natriuretic peptide (−96 ng/L, P = 0.03). CONCLUSIONS In this study, 8 weeks of treatment with dapagliflozin reduced liver PDFF and the volume of visceral adipose tissue in obese patients with type 2 diabetes. Although glycemic control was improved, no effect on tissue-level insulin sensitivity was observed.

Impaired mitochondrial function, oxidative stress and formation of excessive levels of reactive oxygen species play a key role in neurodegeneration in Parkinson’s disease. Myeloperoxidase is a reactive oxygen generating enzyme and is expressed by microglia. The novel compound AZD3241 is a selective and irreversible inhibitor of myeloperoxidase. The hypothesized mechanism of action of AZD3241 involves reduction of oxidative stress leading to reduction of sustained neuroinflammation. The purpose of this phase 2a randomized placebo controlled multicentre positron emission tomography study was to examine the effect of 8 weeks treatment with AZD3241 on microglia in patients with Parkinson’s disease. Parkinson patients received either AZD3241 600 mg orally twice a day or placebo (in 3:1 ratio) for 8 weeks. The binding of ¹¹C-PBR28 to the microglia marker 18 kDa translocator protein, was examined using positron emission tomography at baseline, 4 weeks and 8 weeks. The outcome measure was the total distribution volume, estimated with the invasive Logan graphical analysis. The primary statistical analysis examined changes in total distribution volume after treatment with AZD3241 compared to baseline. Assessments of safety and tolerability of AZD3241 included records of adverse events, vital signs, electrocardiogram, and laboratory tests. The patients had a mean age of 62 (standard deviation = 6) years; 21 were male, three female and mean Unified Parkinson’s Disease Rating Scale III score (motor examination) ranged between 6 and 29. In the AD3241 treatment group (n = 18) the total distribution volume of ¹¹C-PBR28 binding to translocator protein was significantly reduced compared to baseline both at 4 and 8 weeks (P < 0.05). The distribution volume reduction across nigrostriatal regions at 8 weeks ranged from 13–16%, with an effect size equal to 0.5–0.6. There was no overall change in total distribution volume in the placebo group (n = 6). AZD3241 was safe and well tolerated. The reduction of ¹¹C-PBR28 binding to translocator protein in the brain of patients with Parkinson’s disease after treatment with AZD3241 supports the hypothesis that inhibition of myeloperoxidase has an effect on microglia. The results of the present study provide support for proof of mechanism of AZD3241 and warrant extended studies on the efficacy of AZD3241 in neurodegenerative disorders.

Thyroid hormones are important regulators of brown adipose tissue (BAT) development and function. In rodents, BAT metabolism is up-regulated by thyroid hormones. The purpose of this article was to investigate the impact of hyperthyroidism on BAT metabolism in humans. This was a follow-up study using positron emission tomography imaging. Glucose uptake (GU) and perfusion of BAT, white adipose tissue, skeletal muscle, and thyroid gland were measured using [18F]2-fluoro-2-deoxy-D-glucose and [15O]H2O and positron emission tomography in 10 patients with overt hyperthyroidism and in 8 healthy participants. Five of the hyperthyroid patients were restudied after restoration of euthyroidism. Supraclavicular BAT was quantified with magnetic resonance imaging or computed tomography and energy expenditure (EE) with indirect calorimetry. Compared with healthy participants, hyperthyroid participants had 3-fold higher BAT GU (2.7±2.3 vs 0.9±0.1 μmol/100 g/min, P=.0013), 90% higher skeletal muscle GU (P<.005), 45% higher EE (P<.005), and a 70% higher lipid oxidation rate (P=.001). These changes were reversible after restoration of euthyroidism. During hyperthyroidism, serum free T4 and free T3 were strongly associated with EE and lipid oxidation rates (P<.001). TSH correlated inversely with BAT and skeletal muscle glucose metabolism (P<.001). Hyperthyroidism had no effect on BAT perfusion, whereas it stimulated skeletal muscle perfusion (P=.04). Thyroid gland GU did not differ between hyperthyroid and euthyroid study subjects. Hyperthyroidism increases GU in BAT independently of BAT perfusion. Hyperthyroid patients are characterized by increased skeletal muscle metabolism and lipid oxidation rates.

The Ag-mediated electrophilic [¹⁸F]fluorination of an arylboronic ester is reported. This new radiochemical transformation uses [¹⁸F]selectfluor bis(triflate) in acetone. The process gave 6-[¹⁸F]fluoro-L-DOPA with a RCY of 19 ± 12% and a specific activity of 2.6 ± 0.3 GBq μmol⁻¹.