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VBWG Potential role of PPAR activation in CV risk reduction Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. Atherosclerosis Insulin resistance Hyperinsulinemia Obesity Food intake excess Genetic background Physicalinactivity PPAR modulation Dyslipidemia Hyperglycemia Inflammation Hypercoagulation Hypertension
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VBWG Plutzky J. Science. 2003;302:406-7. Peroxisome proliferator-activator receptors (PPARs): Overview Family of steroid hormone nuclear receptors Three isotypes identified –PPAR –PPAR –PPAR Ligand-activated transcription factors regulating metabolic processes
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VBWG Adapted from Plutzky J. Science. 2003;302:406-7. PPAR activation and atherosclerosis: A hypothesis Blunts atherosclerosis Indirect Fat, liver, skeletal muscle Ligand endogenous or synthetic Activated PPAR receptor Reduces inflammation Direct Vascular and inflammatory cells FFA Glucose Insulin sensitivity Triglycerides HDL Cytokines Chemokines Cholesterol efflux Adhesion molecules ?? ??
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VBWG Focus on PPAR activation Inzucchi SE. JAMA. 2002;287:360-72. Reduces insulin resistance Preserves pancreatic -cell function Improves CV risk profile Improves dyslipidemia ( HDL, LDL density, or TG) Renal microalbumin excretion Blood pressure VSMC proliferation/migration in arterial wall PAI-1 levels C-reactive protein levels Adiponectin Free fatty acids
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VBWG PPAR modulators *Withdrawn March 2000 † Also available in combination with metformin or sulfonylurea ‡ Also available in combination with metformin § Dual PPAR / agonist Name Trade name Manufacturer Approval status Troglitazone Rezulin Parke-Davis1997* Rosiglitazone † Avandia GlaxoSmithKline1999 Pioglitazone ‡ Actos Eli Lilly/1999 Takeda Pharmaceuticals Muraglitazar § Pargluva Bristol-Myers Squibb/NDA Merck submitted 2004
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VBWG PPAR modulation: Newest strategy in CV risk reduction Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. Insulin resistance Hypercoagulation Inflammation Hypertension Dyslipidemia PPAR modulation Hyperglycemia Hyperinsulinemia
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VBWG Factors that may drive the progressive decline of -cell function Adapted from Kahn SE. J Clin Endocrinol Metab. 2001;86:4047-58. Adapted from Ludwig DS. JAMA. 2002;287:2414-23. Hyperglycemia (glucose toxicity) -cell Insulin resistance “Lipotoxicity” (elevated FFA, TG)
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VBWG TRIPOD: Evidence that insulin resistance causes -cell failure PPAR activation: 55% relative risk reduction for new-onset diabetes (HR 0.45; 0.25–0.83) Effect was most prominent in women with initial increase in insulin sensitivity and accompanying large reduction in insulin output Protection persisted 8 months after cessation of active treatment PPAR activation associated with preserved -cell function N = 266 Hispanic women with gestational diabetes randomized to troglitazone 400 mg or placebo for median 30 months Buchanan TA et al. Diabetes. 2002;51:2796-803. TRIPOD = Troglitazone in Prevention of Diabetes
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VBWG DPP: Improving insulin sensitivity/ secretion prevents diabetes N = 3234 DPP Research Group. Diabetes. 2005;54:2404-14. pyr = person years IGR = insulin-to-glucose ratio DPP = Diabetes Prevention Program Diabetes hazard rate (per 100 pyr) PlaceboMetforminLifestyle Insulin secretion (IGR) Low High Insulin sensitivity (1/fasting insulin) Medium Insulin secretion (IGR) High Medium Low 0 5 10 15 20 25 30 Low Medium High
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VBWG PPAR activation blunts progression to diabetes DPP Research Group. Diabetes. 2005;54:1150-6. *Terminated early after 1.5 years Diabetes Prevention Program 10 15 5 0 1.5 Cumulative incidence (%) Years 1.00.50.0 Placebo Metformin 850 mg Lifestyle Troglitazone 400 mg* 237 739 15682343n = 75% vs placebo P < 0.001
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VBWG PPAR activation improves -cell function Ovalle F, Bell DSH. Diabetes Care. 2004;27:2585-9. Acute insulin response to glucose (µIU/mL/10 min) –1 0 1 2 3 4 5 Insulin Rosiglitazone 8 mg P = 0.02 Disposition index HOMA-IR N = 17 with type 2 diabetes HOMA-IR = Homeostasis model assessment of insulin resistance Disposition index =
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VBWG CV implications of insulin resistance and PPAR activation Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. Insulin resistance Hyperinsulinemia Hypercoagulation Inflammation Hypertension Hyperglycemia Dyslipidemia PPAR modulation Dyslipidemia
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VBWG Importance of LDL particle density In insulin resistance, LDL-C levels are similar or only slightly elevated vs general population However, atherogenicity of LDL particles varies according to density – More dense = more atherogenic Proportion of small, dense LDL particles greater in patients with insulin resistance or diabetes vs general population Miranda PJ et al. Am Heart J. 2005;149:33-45.
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VBWG Greater atherogenicity of small, dense LDL vs normal LDL Adapted from Sniderman AD et al. Ann Intern Med. 2001;135:447-59. Susceptible to oxidation Binds to arterial wall Penetrates arterial wall Toxic to endothelial cells Promotes PAI-1 production by endothelial cells Promotes thromboxane production by endothelial cells Accumulates Ca 2+ in vascular smooth muscle cells Binds to LDL scavenger receptor
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VBWG Increased small, dense, LDL particles associated with reduced IHD survival St-Pierre AC et al. Arterioscler Thromb Vasc Biol. 2005;25:553-9. N = 2072 men without IHD at baseline;13-year follow-up 1.00 0.90 0.80 Survival probabilities Follow-up (years) 024681012 P < 0.001 Tertiles of LDL-C 255Å <1.07 mmol/l 1.07–1.86 mmol/l≥1.86 mmol/l IHD = ischemic heart disease
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VBWG PPAR activation increases LDL size and buoyancy Brunzell JD et al. Circulation. 2004;110(suppl):III-143. N = 302; rosiglitazone 8 mg 4.8 0 4 8 0.019 0 0.02 0.04 LDL particle size LDL density Diameter vs baseline (Angstroms) Relative flotation vs baseline P < 0.0001
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VBWG Comparative effects of PPAR activators on lipids in diabetes 1 Goldberg RB et al. Diabetes Care. 2005;28:1547-54. 2 Plotkin DJ et al. Diabetes. 2005;54(suppl 1):A232. 3 Khan M et al. Diabetes. 2005;54(suppl 1):A137. In patients not receiving statin therapy, studies suggest that pioglitazone and rosiglitazone have differing effects on lipid levels and particle size 1 In patients receiving statin therapy, some studies suggest these differences are eliminated, while other studies suggest they persist 2 Clinical implications are not known 3
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VBWG CV implications of insulin resistance and PPAR activation Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. Insulin resistance Hyperinsulinemia Hypercoagulation Inflammation Hypertension Hyperglycemia Dyslipidemia PPAR modulation Inflammation
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VBWG Adipokines: An overview CRP IL-6 PAI-1 Angiotensinogen Leptin Resistin MCP-1 Adiponectin Lau DCW et al. Am J Physiol Heart Circ Physiol. 2005;288:H2031-41. Wellen KE, Hotamisligil GS. J Clin Invest. 2005;115:1111-9. Atherogenic Antiatherogenic
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VBWG Adiponectin associated with decreased risk of MI PischonT et al.JAMA. 2004;291:1730-7. Adjusted relative risk (P < 0.001)Lipid-adjusted relative risk (P < 0.02) 12345 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Quintile ofadiponectin(95% CI) N = 18,225 men; 6-year follow-up 7.912.616.521.129.2 g/mL Relative risk
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VBWG Improved insulin sensitivity associated with increased adiponectin N = 40 women with gestational diabetes treated with troglitazone for 3 months Pajvani UB et al. J Biol Chem. 2004;279:12152-62. % Change in insulin sensitivity ( S i ) –50 –100 200 400 500 % Change in HMW/total adiponectin ( S A ) 300 100 –25255075100
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VBWG Lau DCW et al. Am J Physiol Heart Circ Physiol. 2005;288:H2031-41. Contrasting roles of CRP and PPAR on inflammation and insulin resistance Adipose tissue Liver IL-6 PPAR CRP Glucose Insulin resistance
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VBWG Direct relationship of CRP to metabolic syndrome Women’s Health Study; N = 14,719 Ridker PM et al. Circulation. 2003;107:391-7. 8 6 0 Median CRP (mg/L) Components of the metabolic syndrome (n) 4 012345 2 n = 4086 3884 3152 2292 1135 170 Modified ATP III definition
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VBWG Inflammation is a contributing mechanism in diabetes development Festa A et al. Diabetes. 2002;51:1131-7. 0 5 10 15 20 25 Fibrinogen CRP PAI-1 P = 0.06P = 0.001 1st 2nd 3rd 4th N = 1047 Quartiles of inflammatory proteins Incidence (%)
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VBWG PPAR activation decreases CRP in patients with diabetes Mean change from baseline (%) Haffner SM et al. Circulation. 2002;106:679-84. 27% –50 –40 –30 –20 –10 0 Placebo Rosiglitazone 4 mg Rosiglitazone 8 mg 22% P < 0.05 N = 357; 26 weeks
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VBWG CV implications of insulin resistance and PPAR activation Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. Insulin resistance Hyperinsulinemia Hypercoagulation Inflammation Hypertension Hyperglycemia Dyslipidemia PPAR modulation Hypertension
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VBWG Raji A et al. Diabetes Care. 2003;26:172-8. –20 –10 0 10 20 –2–10123 Change in insulin sensitivity (mg/kg/min) in 24-h systolic BP (mm Hg) P < 0.005 r = –0.59 N = 24 nondiabetic hypertensives; rosiglitazone 8 mg, 16 weeks Improved insulin sensitivity associated with reduced BP VBWG Nonmodulators Low-renin hypertension
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VBWG PPAR activation associated with sustained BP reduction N = 668 with type 2 diabetes Home PD et al. Diabetes. 2005;54(suppl 1):A134. –6–5–4–3–2–110 24-h systolic BP * Reduction from baseline (mm Hg, 95% CI) –5–4–3–2–110 24-h diastolic BP * Treatment differences (mm Hg, 95% CI) 6 months 12 months Baseline sulfonylurea 6 months 12 months Baseline metformin * Ambulatory BP Rosiglitazone added to baseline therapy
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VBWG Adapted from Tenenbaum A et al. Intl J Cardiol. 2004;97:167-72. CV implications of insulin resistance and PPAR activation Insulin resistance PPAR modulation Hyperinsulinemia Hypercoagulation Inflammation Hyperglycemia Dyslipidemia Hypertension
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VBWG PPAR activation blunts TNF- –induced PAI-1 secretion Hamaguchi E et al. J Pharmacol Exp Ther. 2003;307:987-94. Trog = troglitazone *P < 0.001 † P < 0.005 Human umbilical-vein endothelial cells 800 600 400 200 0 PAI-1 (ng) * † TNF- 1 ng/mL TNF- 10 ng/mL TNF- 1 ng/mL + Trog 10 µM TNF- 10 ng/mL + Trog 10 µM TNF- 100 ng/mL + Trog 10 µM TNF- 100 ng/mL *
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VBWG BasalPlacebo Metformin 2.5 g PAI-1 activity (U/mL) * P = 0.001 vs placebo Results at 12 weeks 35 30 25 20 15 10 5 0 A1C = –1.3% FPG = –55 mg/dL * N = 27, 12 weeks Metformin reduces PAI-1 levels in type 2 diabetes Nagi DK, Yudkin JS. Diabetes Care. 1993;16:621-9.
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VBWG Weissman PN et al. Diabetes. 2004;53(suppl 2):A28. – 9.8 – 0.56 22.2 –40 –30 –20 –10 0 10 20 30 CRPPAl-1 MMP-9 – 26.9 – 32.76 – 14.35 *NS vs baseline Baseline (%) Metformin 2 g (n = 70)Metformin 1 g + rosiglitazone 8 mg (n = 57) P = 0.026 P < 0.001 P = 0.046 Benefits of combined insulin sensitizer therapy: Effects on CRP, PAl-1, and MMP-9 * * Weeks 8–24
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