A Selective Peroxisome Proliferator-Activated Receptor Agonist, CP-900691, Improves Plasma Lipids, Lipoproteins, and Glycemic Control in Diabetic Monkeys

Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of lipid and glucose metabolism. PPAR agonists improve insulin sensitivity and hyperglycemia and are effective in treating type 2 diabetes mellitus (T2DM), whereas PPAR agonists are used to treat dyslipidemia and atherosclerosis. The goal here was to examine the efficacy of a selective PPAR agonist {(S)-3-[3-(1-carboxy1-methyl-ethoxy)-phenyl]-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester; CP-900691} on lipid, glycemic, and inflammation indices in 14 cynomolgus monkeys with spontaneous T2DM maintained on daily insulin therapy. Monkeys were dosed orally with either vehicle (n 7) or CP-900691 (3 mg/kg, n 7) daily for 6 weeks. CP-900691 treatment increased plasma high-density lipoprotein cholesterol (HDLC) (33 3 to 60 4 mg/dL, p 0.001) and apolipoprotein A1 (96 5 to 157 5 mg/dL, p 0.001), reduced plasma triglycerides (547 102 to 356 90 mg/dL, p 0.01), and apolipoprotein B (62 3 to 45 3 mg/dL, p 0.01), improved the lipoprotein index (HDL to non-HDLC ratio; 0.28 0.06 to 0.79 0.16, p 0.001), decreased body weight (p 0.01) and C-reactive protein (CRP) (1700 382 to 304 102 ng/ml, p 0.01), and increased adiponectin (1697 542 to 4242 1070 ng/ml, p 0.001) compared with baseline. CP-900691 treatment reduced exogenous insulin requirements by approximately 25% (p 0.04) while lowering plasma fructosamine from 2.87 0.09 to 2.22 0.17 mM (p 0.05), indicative of improved glycemic control. There were no changes in any of the aforementioned parameters in the vehicle group. Because low HDLC and high triglycerides are well established risk factors for cardiovascular disease, the marked improvements in these parameters, and in glycemic control, body weight, and CRP, suggest that CP-900691 may be of benefit in diabetic and obese or hyperlipidemic populations. The peroxisome proliferator-activated receptors (PPAR , PPAR , and PPAR ) are a family of distinct nuclear receptors that associate with key naturally occurring lipid molecules and function as transcription factors in the regulation of carbohydrate and lipid metabolism, among other biological processes (Harwood and Hamanaka, 1998; Corton et al., 2000; Willson et al., 2000; Winegar et al., 2001). The PPARs became recognized as important pharmaceutical targets for the treatment of dyslipidemia, diabetes, and the cardiovascular disorders associated with obesity and the metabolic syndrome, when it was discovered that PPAR was the therapeutic target for the marketed glitazone class of antidiabetic agents (Willson et al., 2000, 2001; Picard and Auwerx, 2002) and PPAR was the therapeutic target for the marketed fibrate class of antidyslipidemic agents (Harwood and Hamanaka, 1998; Willson et al., 2000; Winegar et al., 2001). Because the pharmacological actions of PPAR , PPAR , and PPAR activators are distinct (Corton et al., 2000; Willson et This work was supported by a grant from Pfizer, Inc. This work was presented previously in abstract form: Flynn M, Shadoan MK, Kavanagh K, Zhang L, Auerbach BJ, Harwood HJ, and Wagner JD (2007) A novel selective PPARagonist, CP900691, improves plasma lipids, lipoproteins, glycemic control and reduces body weight in diabetic monkeys. Diabetes 56 (Suppl 1):A138. Article, publication date, and citation information can be found at http://jpet.aspetjournals.org. doi:10.1124/jpet.110.166736. ABBREVIATIONS: PPAR, peroxisomal proliferator-activated receptor; CP-900691, (S)-3-[3-(1-carboxy-1-methyl-ethoxy)-phenyl]-piperidine-1carboxylic acid 4-trifluoromethyl-benzyl ester; T2DM, type 2 diabetes mellitus; HDL, high-density lipoprotein; VLDL, very low-density lipoprotein; LDL, low-density lipoprotein; HDLC, high-density lipoprotein cholesterol; apoA1, apolipoprotein A1; apoB, apolipoprotein B; ITT, insulin tolerance test; CRP, C-reactive protein; ANOVA, analysis of variance; TG, triglyceride; ELISA, enzyme-linked immunosorbent assay. 0022-3565/10/3333-844–853$20.00 THE JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS Vol. 333, No. 3 Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics 166736/3584635 JPET 333:844–853, 2010 Printed in U.S.A. 844 at A PE T Jornals on O cber 9, 2017 jpet.asjournals.org D ow nladed from al., 2000) and exhibit distinct side effect profiles (Corton et al., 2000; Willson et al., 2000; Jones, 2001; Picard and Auwerx, 2002), there has been a focused effort in the pharmaceutical industry to develop potent PPAR agonists that exhibit a high degree of specificity for activation of individual receptor subtypes (Harwood and Hamanaka, 1998; Corton et al., 2000; Willson et al., 2000; Jones, 2001; Picard and Auwerx, 2002). PPAR , which is highly expressed in liver, skeletal muscle, and heart and activated by a variety of naturally occurring lipids and the fibrate class of dyslipidemic drugs, potentiates fatty acid oxidation and modulates lipoprotein metabolism (Corton et al., 2000; Willson et al., 2000). Fibrates such as fenofibrate, for example, have been shown in both laboratory and clinical studies to reduce plasma triglyceride (TG) levels, reduce the number of circulating triglyceride-rich apolipoprotein B (apoB)-containing very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) particles, increase highdensity lipoprotein cholesterol (HDLC) levels through increases in apolipoprotein A1 (apoA1) production, and favorably affect atherosclerotic progression and cardiovascular outcomes (Corton et al., 2000; Faergeman, 2000; Willson et al., 2000; Jones, 2001; Castrillo and Tontonoz, 2004; Li et al., 2004). Recent clinical studies evaluating chronic treatment with the PPAR activators fenofibrate and bezafibrate have indeed demonstrated improvement in total, HDL, and LDL cholesterol and triglycerides, and corresponding reductions in atherosclerotic progression (Diabetes Atherosclerosis Intervention Investigators, 2001) and improved cardiovascular outcomes (Elkeles et al., 1998). Though primarily involved in lipid metabolism, PPAR may also provide a link between dyslipidemia and diabetes, because T2DM patients generally also present with a variety of dyslipidemias, such as increased TG and circulating fatty acids and decreased HDLC, which further predisposes them to cardiovascular disease (Willson et al., 2000). In insulinresistant rodents, fibrates have been shown to decrease adiposity and improve insulin sensitivity, attenuating both hyperinsulinemia and hyperglycemia (Guerre-Millo et al., 2000). In addition, the PPAR agonist fenofibrate has been shown to lower plasma TG and LDL cholesterol concentrations, increase plasma HDLC, and ameliorate hyperinsulinemia in obese rhesus monkeys (Winegar et al., 2001) and elevate HDLC levels in vervet monkeys (Wallace et al., 2005). However, supraphysiological glucose levels in vitro and hyperglycemia in vivo have been shown to attenuate PPAR mRNA expression in -cells and PPAR expression in islets, respectively, and may negatively affect PPAR -related -cell lipid oxidation (Roduit et al., 2000). Furthermore, fenofibrate is not specific for PPAR activation and shows a similar degree of PPAR activation (Willson et al., 2000; Jones, 2001), thus confounding interpretation of the role of PPAR agonism in glycemic regulation. Similar to human T2DM patients, diabetic cynomolgus monkeys exhibit increased plasma concentrations of TG and VLDL cholesterol and decreased HDLC concentrations (Wagner et al., 2006), all of which may be favorably altered by PPAR activation. To determine whether pharmacologic PPAR activation by highly specific PPAR agonists would lead to improved insulin sensitivity and exhibit favorable effects on dyslipidemia, we have examined the effects of a highly selective PPAR agonist, (S)-3-[3-(1carboxy-1-methyl-ethoxy)-phenyl]-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester (CP-900691) (Hayward et al., 2006), on lipid and glycemic indices in this clinically relevant animal model of diabetic dyslipidemia. Materials and Methods Characteristics of CP-900691. CP-900691 (Fig. 1) is a specific, saturable, high-affinity ligand for PPAR , as demonstrated in scintillation-proximity competition ligand binding assays using recombinant human PPAR , PPAR , and PPAR receptor subtype ligand binding domains, where IC50 values for PPAR , PPAR , and PPAR competition with standard radiolabeled ligands averaged 12.5 0.4, 10,000, and 1520 170 nM, respectively. The 122-fold specificity relative to PPAR binding and apparent lack of binding of CP-900691 to PPAR was paralleled by 81and 207-fold specificities relative to PPAR and PPAR activation, respectively (PPAR EC50 22 nM, PPAR EC50 4548 nM, and PPAR EC5