Rationale and design of a multicenter randomized study for evaluating vascular function under uric acid control using the xanthine oxidase inhibitor, febuxostat : the PRIZE study

Background: Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces endothelial dysfunction and inflammatory reactions in vascular systems, leading to atherosclerosis. Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. We designed the PRIZE study to evaluate the effects of febuxostat on a surrogate marker of cardiovascular disease risk, ultrasonography-based intima-media thickness of the carotid artery in patients with hyperuricemia. Methods: The study is a multicenter, prospective, randomized, open-label and blinded-endpoint evaluation (PROBE) design. A total of 500 patients with asymptomatic hyperuricemia (uric acid >7.0 mg/dL) and carotid intima-media thickness ≥1.1 mm will be randomized centrally to receive either febuxostat (10–60 mg/day) or non-pharmacological treatment. Randomization is carried out using the dynamic allocation method stratified according to age (<65, ≥65 year), gender, presence or absence of diabetes mellitus, serum uric acid (<8.0, ≥8.0 mg/dL), and carotid intima-media thickness (<1.3, ≥1.3 mm). In addition to administering the study drug, we will also direct lifestyle modification in all participants, including advice on control of body weight, sleep, exercise and healthy diet. Carotid intima-media thickness will be evaluated using ultrasonography performed by skilled technicians at a central laboratory. Follow-up will be continued for 24 months. The primary endpoint is percentage change in mean intima-media thickness of the common carotid artery 24 months after baseline, measured by carotid ultrasound imaging. Conclusions: PRIZE will be the first study to provide important data on the effects of febuxostat on atherosclerosis in patients with asymptomatic hyperuricemia

Febuxostat and carotid atherosclerosis in asymptomatic hyperuricemia

Background An elevated level of serum uric acid (SUA) is associated with an increased risk of cardiovascular disease. Pharmacological intervention with urate-lowering agents, such as the conventional purine analogue xanthine oxidase (XO) inhibitor, allopurinol, has been used widely for a long period of time in clinical practice to reduce SUA levels. Febuxostat, a novel non-purine selective inhibitor of XO, has higher potency for inhibition of XO activity and greater urate-lowering efficacy than conventional allopurinol. However, clinical evidence regarding the effects of febuxostat on atherosclerosis is lacking. The purpose of the study was to test whether treatment with febuxostat delays carotid intima-media thickness (IMT) progression in patients with asymptomatic hyperuricemia. Methods and findings The study was a multicenter, prospective, randomized, open-label, blinded-endpoint clinical trial undertaken at 48 sites throughout Japan between May 2014 and August 2018. Adults with both asymptomatic hyperuricemia (SUA >7.0 mg/dL) and maximum IMT of the common carotid artery (CCA) ≥1.1 mm at screening were allocated equally using a central web system to receive either dose-titrated febuxostat (10–60 mg daily) or as a control-arm, non-pharmacological lifestyle modification for hyperuricemia, such as a healthy diet and exercise therapy. Of the 514 enrolled participants, 31 were excluded from the analysis, with the remaining 483 people (mean age 69.1 years [standard deviation 10.4 years], female 19.7%) included in the primary analysis (febuxostat group, 239; control group, 244), based on a modified intention-to-treat principal. The carotid IMT images were recorded by a single sonographer at each site and read in a treatment-blinded manner by a single analyzer at a central core laboratory. The primary endpoint was the percentage change from baseline to 24 months in mean IMT of the CCA, determined by analysis of covariance using the allocation adjustment factors (age, gender, history of type 2 diabetes, baseline SUA, and baseline maximum IMT of the CCA) as the covariates. Key secondary endpoints included changes in other carotid ultrasonographic parameters and SUA and the incidence of clinical events. The mean values (± standard deviation) of CCA-IMT were 0.825 mm ± 0.173 mm in the febuxostat group and 0.832 mm ± 0.175 mm in the control group (mean between-group difference [febuxostat − control], −0.007 mm [95% confidence interval (CI) −0.039 mm to 0.024 mm; P = 0.65]) at baseline; 0.832 mm ± 0.182 mm in the febuxostat group and 0.848 mm ± 0.176 mm in the control group (mean between-group difference, −0.016 mm [95% CI −0.051 mm to 0.019 mm; P = 0.37]) at 24 months. Compared with the control group, febuxostat had no significant effect on the primary endpoint (mean percentage change 1.2% [95% CI −0.6% to 3.0%] in the febuxostat group (n = 207) versus 1.4% [95% CI −0.5% to 3.3%] in the control group (n = 193); mean between-group difference, −0.2% [95% CI −2.3% to 1.9%; P = 0.83]). Febuxostat also had no effect on the other carotid ultrasonographic parameters. The mean baseline values of SUA were comparable between the two groups (febuxostat, 7.76 mg/dL ± 0.98 mg/dL versus control, 7.73 mg/dL ± 1.04 mg/dL; mean between-group difference, 0.03 mg/dL [95% CI −0.15 mg/dL to 0.21 mg/dL; P = 0.75]). The mean value of SUA at 24 months was significantly lower in the febuxostat group than in the control group (febuxostat, 4.66 mg/dL ± 1.27 mg/dL versus control, 7.28 mg/dL ± 1.27 mg/dL; mean between-group difference, −2.62 mg/dL [95% CI −2.86 mg/dL to −2.38 mg/dL; P < 0.001]). Episodes of gout arthritis occurred only in the control group (4 patients [1.6%]). There were three deaths in the febuxostat group and seven in the control group during follow-up. A limitation of the study was the study design, as it was not a placebo-controlled trial, had a relatively small sample size and a short intervention period, and only enrolled Japanese patients with asymptomatic hyperuricemia. Conclusions In Japanese patients with asymptomatic hyperuricemia, 24 months of febuxostat treatment did not delay carotid atherosclerosis progression, compared with non-pharmacological care. These findings do not support the use of febuxostat for delaying carotid atherosclerosis in this population

Rationale and design of a multicenter randomized controlled study to evaluate the preventive effect of ipragliflozin on carotid atherosclerosis : the PROTECT study

Background: Type 2 diabetes mellitus is associated strongly with an increased risk of micro- and macro-vascular complications, leading to impaired quality of life and shortened life expectancy. In addition to appropriate glycemic control, multi-factorial intervention for a wide range of risk factors, such as hypertension and dyslipidemia, is crucial for management of diabetes. A recent cardiovascular outcome trial in diabetes patients with higher cardiovascular risk demonstrated that a SGLT2 inhibitor markedly reduced mortality, but not macro-vascular events. However, to date there is no clinical evidence regarding the therapeutic effects of SGLT2 inhibitors on arteriosclerosis. The ongoing PROTECT trial was designed to assess whether the SGLT2 inhibitors, ipragliflozin, prevented progression of carotid intima-media thickness in Japanese patients with type 2 diabetes mellitus. Methods: A total of 480 participants with type 2 diabetes mellitus with a HbA1c between 6 and 10 % despite receiving diet/exercise therapy and/or standard anti-diabetic agents for at least 3 months, will be randomized systematically (1:1) into either ipragliflozin or control (continuation of conventional therapy) groups. After randomization, ipragliflozin (50–100 mg once daily) will be added on to the background therapy in participants assigned to the ipragliflozin group. The primary endpoint of the study is the change in mean intima-media thickness of the common carotid artery from baseline to 24 months. Images of carotid intima-media thickness will be analyzed at a central core laboratory in a blinded manner. The key secondary endpoints include the change from baseline in other parameters of carotid intima-media thickness, various metabolic parameters, and renal function. Other cardiovascular functional tests are also planned for several sub-studies. Discussion: The PROTECT study is the first to assess the preventive effect of ipragliflozin on progression of carotid atherosclerosis using carotid intima-media thickness as a surrogate marker. The study has potential to clarify the protective effects of ipragliflozin on atherosclerosis

Computational Analysis of the Interaction Energies between Amino Acid Residues of the Measles Virus Hemagglutinin and Its Receptors

Measles virus (MV) causes an acute and highly devastating contagious disease in humans. Employing the crystal structures of three human receptors, signaling lymphocyte-activation molecule (SLAM), CD46, and Nectin-4, in complex with the measles virus hemagglutinin (MVH), we elucidated computationally the details of binding energies between the amino acid residues of MVH and those of the receptors with an ab initio fragment molecular orbital (FMO) method. The calculated inter-fragment interaction energies (IFIEs) revealed a number of significantly interacting amino acid residues of MVH that played essential roles in binding to the receptors. As predicted from previously reported experiments, some important amino-acid residues of MVH were shown to be common but others were specific to interactions with the three receptors. Particularly, some of the (non-polar) hydrophobic residues of MVH were found to be attractively interacting with multiple receptors, thus indicating the importance of the hydrophobic pocket for intermolecular interactions (especially in the case of Nectin-4). In contrast, the electrostatic interactions tended to be used for specific molecular recognition. Furthermore, we carried out FMO calculations for in silico experiments of amino acid mutations, finding reasonable agreements with virological experiments concerning the substitution effect of residues. Thus, the present study demonstrates that the electron-correlated FMO method is a powerful tool to search exhaustively for amino acid residues that contribute to interactions with receptor molecules. It is also applicable for designing inhibitors of MVH and engineered MVs for cancer therapy

Identifying the spin transition in Fe2+-rich MgSiO3 perovskite from X-ray diffraction and vibrational spectroscopy

Based on numerical results from density-functional perturbation theory calculations, we show that the magnetic spin transition in Fe2+-rich MgSiO3 perovskite can be identified as changes in the powder X-ray diffraction (XRD) pattern and the vibrational spectra. In particular theory predicts how the symmetry breaking and the volume reduction associated with the spin transition affects both structural and vibrational properties. The XRD measurements of (Mg0.5Fe0.3)SiO3 perovskite indeed demonstrated that the new diffraction peaks and the peak broadening formed during the spin transition can be explained by the associated symmetry breaking. We also show computationally that certain vibrational peaks exhibit a shift at the transition; the Gruneisen parameters of certain modes are affected by the transition, thus bearing on the thermodynamical properties. Raman and/or infrared measurements before and after the spin transition could identify these changes