Elsevier

Metabolism

Volume 65, Issue 6, June 2016, Pages 904-914
Metabolism

Translational
Effects of the BET-inhibitor, RVX-208 on the HDL lipidome and glucose metabolism in individuals with prediabetes: A randomized controlled trial

https://doi.org/10.1016/j.metabol.2016.03.002Get rights and content

Abstract

Aims

High-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I) can modulate glucose metabolism through multiple mechanisms. This study determined the effects of a novel bromodomain and extra-terminal (BET) inhibitor (RVX-208) and putative apoA-I inducer on lipid species contained within HDL (HDL lipidome) and glucose metabolism.

Materials and methods

Twenty unmedicated males with prediabetes received 100 mg b.i.d. RVX-208 and placebo for 29–33 days separated by a wash-out period in a randomized, cross-over design trial. Plasma HDL-cholesterol and apoA-I were assessed as well as lipoprotein particle size and distribution using NMR spectroscopy. An oral glucose tolerance test (OGTT) protocol with oral and infused stable isotope tracers was employed to assess postprandial plasma glucose, indices of insulin secretion and insulin sensitivity, glucose kinetics and lipolysis. Whole plasma and HDL lipid profiles were measured using mass spectrometry.

Results

RVX-208 treatment for 4 weeks increased 6 sphingolipid and 4 phospholipid classes in the HDL lipidome (p  0.05 versus placebo), but did not change conventional clinical lipid measures. The concentration of medium-sized HDL particles increased by 11% (P = 0.01) and small-sized HDL particles decreased by 10% (P = 0.04) after RVX-208 treatment. In response to a glucose load, after RVX-208 treatment, plasma glucose peaked at a similar level to placebo, but 30 min later with a more sustained elevation (treatment effect, P = 0.003). There was a reduction and delay in total (P = 0.001) and oral (P = 0.003) glucose rates of appearance in plasma and suppression of endogenous glucose production (P = 0.014) after RVX-208 treatment. The rate of glucose disappearance was also lower following RVX-208 (P = 0.016), with no effect on glucose oxidation or total glucose disposal.

Conclusions

RVX-208 increased 10 lipid classes in the plasma HDL fraction, without altering the concentrations of either apoA-I or HDL-cholesterol (HDL-C). RVX-208 delayed and reduced oral glucose absorption and endogenous glucose production, with plasma glucose maintained via reduced peripheral glucose disposal. If sustained, these effects may protect against the development of type 2 diabetes.

Introduction

HDL and its major apolipoprotein, apoA-I can directly modulate glucose metabolism through multiple mechanisms [1], [2], [3]. In the clinical setting, acute HDL elevation via short-term reconstituted HDL (rHDL) infusion [1] and chronically raising HDL via a cholesteryl ester transfer protein (CETP) inhibitor [3] reduce blood glucose in individuals with type 2 diabetes mellitus (T2DM). This is underpinned by at least two known mechanisms, namely increased insulin secretion [1], [4], [5] and enhanced skeletal muscle glucose uptake via an AMP-activated protein kinase (AMPK)-mediated mechanism [1]. HDL may also act via a third mechanism to increase insulin sensitivity via lipid removal and anti-inflammatory actions in metabolic tissues [6]. These newly described roles of HDL relating to glucose metabolism [2] suggest therapies that target HDL and/or apoA-I may have relevance in the management of T2DM.

The focus of HDL therapies has evolved in the light of recent data showing that HDL particle number, composition and function relate more closely to cardiovascular outcome than standard clinical measures of HDL-C content [7], [8], [9]. As a result, compounds targeting apoA-I are of particular interest due to their potential to increase HDL particle number and favorably alter the lipid composition and function of existing particles [8], [10]. RVX-208 is an orally active small molecule which induces apoA-I through selective inhibition of BET proteins [11], [12], [13]. In African green monkeys, 60 mg/kg RVX-208 increased plasma apoA-I and HDL-C by 53% and 97% respectively after 28 days treatment [11]. In a follow-up phase I clinical trial in healthy volunteers RVX-208 (1–20 mg/kg/day) treatment for 7 days induced a 10% increase in plasma apoA-I and an 11% increase in the cholesterol efflux capacity of post-treatment plasma. To minimize potential liver transaminase elevations in humans, lower doses (100–150 mg b.i.d) of RVX-208 inducing more modest elevations in plasma apoA-I levels (3–6%) and HDL-C (6–8%) over a 12 week period have been investigated, with no evidence of hepatotoxicity [14]. Beyond the effects of RVX-208 on clinical lipid parameters, modification of the relative quantity of the hundreds of lipid species within HDL is one possible mechanism mediating the functional properties of HDL.

The objectives of the current study were to determine the effects of RVX-208 on the HDL lipidome and postprandial glucose metabolism in individuals with prediabetes following a glucose load. Effects on glucose kinetics, insulin secretion and whole-body insulin sensitivity were determined during a modified frequently sampled oral glucose tolerance test (OGTT) [15], incorporating stable isotope tracers.

Section snippets

Patient Population and Screening

Twenty males aged 38–69 years with prediabetes based on WHO criteria (fasting blood glucose 6.1–6.9 mmol/L and/or 2 h blood glucose 7.8–11.0 mmol/L after a 75 g oral glucose load), body mass index (BMI) of 25–40 kg/m2 and HDL-C levels ≤ 1.4 mmol/L were enrolled. Smoking, previous history of major illness and any prescription or over-the-counter medications were all exclusion criteria (see Supplementary Fig. 1 for CONSORT diagram). Patient characteristics and demographics are presented in Table 1. The

Baseline Characteristics

At screening, participants were either overweight or obese (BMI 30 ± 4 kg/m2) and had impaired glucose tolerance, with three individuals also presenting with impaired fasting glucose. Average glycated hemoglobin (HbA1c) was 5.8 ± 0.4% (39.9 ± 4.5 mmol/mol) and circulating HDL-C was 1.0 ± 0.2 mmol/L. A summary of the baseline characteristics is presented in Table 1.

Clinical Measures

Adherence to medication regimens based on pill counts was high (> 98%) and not different between interventions (Table 2). There was no

Discussion

This is the first report showing that an orally active BET-inhibitor may modulate glucose metabolism. Four weeks of treatment with RVX-208 led to a reduction in the appearance of an oral glucose load in the circulation associated with reduced endogenous glucose production, balanced by reduced glucose disposal. The net effect in this population with prediabetes was a delayed, but also sustained peak in plasma glucose following a glucose challenge. The reduction in oral glucose absorption may be

Conclusions

This is the first evidence that 4 weeks of RVX-208 treatment is sufficient to induce subtle changes in glucose metabolism, in association with changes in the HDL lipidome. RVX-208 delayed and reduced the appearance of oral glucose in the circulation in association with reduced endogenous glucose production. This was accompanied by a reduction in glucose disposal, which acted to sustain peak plasma glucose following RVX-208 treatment. RVX-208 also altered the HDL lipidome, increasing lipid

Author Contributions

ALS, MFF, GVH, KAR, JJ, AG, NCWW, DS, PB, SJD, PJM and BAK were involved in the conception and design of the study. ALS, SKT, MFF, AKN, MR, ALC and SJD were involved in acquisition of data. ALS, SKT, PAM, KH, AAK, ALC, GVH, CC, CD, JDO, KAR, PJM and BAK were involved in analysis and interpretation of data. ALS, SKT and BAK drafted the article. All authors revised the article critically for important intellectual content and gave final approval of the version to be submitted.

Funding

This study was supported by Resverlogix Corp., the National Health & Medical Research Council (NHMRC) of Australia (APP1065462) to BAK, SJD and ALS, and in part by the Victorian Government's Operational Infrastructure Support (OIS) Program. BAK, DS and PJM are all supported by NHMRC Research Fellowships.

Disclosure Statement

JJ and NCWW are employees, share- and option holders of Resverlogix Corporation. JDO is employed by LabCorp. BAK received a research grant and travel support from Resverlogix Corporation.

Acknowledgments

The authors would like to thank Dr. Wayne Childs, Donna Vizi and Jenny Starr (Alfred Hospital, Cardiology Department, Melbourne, Victoria, Australia) for their technical assistance and the research participants for their time and interest in our study. This was an investigator-initiated project. While Resverlogix Corp. was permitted to review the manuscript and suggest changes, they played no role in data analysis.

References (33)

  • P.J. Barter et al.

    Effect of torcetrapib on glucose, insulin, and hemoglobin A1c in subjects in the investigation of lipid level management to understand its impact in atherosclerotic events (ILLUMINATE) trial

    Circulation

    (2011)
  • M.A. Fryirs et al.

    Effects of high-density lipoproteins on pancreatic beta-cell insulin secretion

    Arterioscler Thromb Vasc Biol

    (2010)
  • A.L. Siebel et al.

    Effects of high-density lipoprotein elevation with cholesteryl ester transfer protein inhibition on insulin secretion

    Circ Res

    (2013)
  • A.L. Carey et al.

    Skeletal muscle insulin resistance associated with cholesterol-induced activation of macrophages is prevented by high density lipoprotein

    PLoS One

    (2013)
  • A. Rohatgi et al.

    HDL cholesterol efflux capacity and incident cardiovascular events

    N Engl J Med

    (2014)
  • B.A. Kingwell et al.

    HDL-targeted therapies: progress, failures and future

    Nat Rev Drug Discov

    (2014)
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