PPARalpha, but not PPARgamma, activators decrease macrophage-laden atherosclerotic lesions in a nondiabetic mouse model of mixed dyslipidemia.
OBJECTIVE
Peroxisome proliferator-activated receptor (PPAR) alpha and gamma are nuclear receptors that may modulate atherogenesis, not only by correcting metabolic disorders predisposing to atherosclerosis but also by directly acting at the level of the vascular wall. The accumulation of lipid-laden macrophages in the arterial wall is an early pivotal event participating in the initiation and promotion of atherosclerotic lesion formation. Because PPARalpha and gamma modulate macrophage gene expression and cellular function, it has been suggested that their ligands may modulate atherosclerosis development via direct effects on macrophages. In this report, we investigated the effect of a PPARalpha ligand (fenofibrate) and 2 PPARgamma ligands (rosiglitazone and pioglitazone) on atherogenesis in a dyslipidemic nondiabetic murine model that develops essentially macrophage-laden lesions.


RESULTS
Mice were fed a Western diet supplemented or not with fenofibrate (100 mpk), rosiglitazone (10 mpk), or pioglitazone (40 mpk) for 10 weeks. Atherosclerotic lesions together with metabolic parameters were measured after treatment. Fenofibrate treatment significantly improved lipoprotein metabolism toward a less atherogenic phenotype but did not affect insulin sensitivity. Contrarily, rosiglitazone and pioglitazone improved glucose homeostasis, whereas they did not improve lipoprotein metabolism. Fenofibrate treatment significantly decreased the accumulation of lipids and macrophages in the aortic sinus. However, surprisingly, neither rosiglitazone nor pioglitazone had an effect on lesion lipid accumulation or macrophage content.


CONCLUSIONS
These results indicate that in a dyslipidemic nondiabetic murine model, PPARalpha, but not PPARgamma, activators protect against macrophage foam cell formation.
INSERM U545, Département d'Athérosclerose, Institut Pasteur de Lille, 1 rue du Professeur Calmette, 59019 Lille cédex, France.
Nathalie
N
Hennuyer
Anne
A
Tailleux
Gérard
G
Torpier
Hafid
H
Mezdour
Jean-Charles
JC
Fruchart
Bart
B
Staels
Catherine
C
Fiévet
D000818:Animals; D053329:Apolipoprotein E2; D001057:Apolipoproteins E / Q000235:genetics; D050197:Atherosclerosis / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D001786:Blood Glucose / Q000187:drug effects; D004195:Disease Models, Animal; D050171:Dyslipidemias / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D005260:Female; D011345:Fenofibrate / Q000494:pharmacology*; D005487:Foam Cells / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008817:Mice, Mutant Strains; D047493:PPAR alpha / Q000819:agonists* / Q000378:metabolism; D047495:PPAR gamma / Q000819:agonists* / Q000378:metabolism; D000077205:Pioglitazone; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology
D053329:Apolipoprotein E2; D001057:Apolipoproteins E; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D000960:Hypolipidemic Agents; D047493:PPAR alpha; D047495:PPAR gamma; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D011345:Fenofibrate; D000077205:Pioglitazone