Treatment of obesity with diet/exercise versus pioglitazone has distinct effects on lipoprotein particle size.
OBJECTIVE
We compared the effects of diet/exercise induce weight loss versus pioglitazone on lipoprotein particle characteristics in non-diabetic, insulin resistant adults to determine whether the responses and potential mechanisms for improvement are similar between these two insulin sensitizing regimens.


RESULTS
Thirty-seven obese, insulin resistant volunteers were randomized to 19 weeks of either pioglitazone or diet/exercise treatment. Insulin sensitivity (Si) by IVGTT and lipoprotein subclass particle profiles by NMR was measured. Only diet/exercise lowered TG (-40+/-11 mg/dL), total (-29+/-4 mg/dL) and LDL cholesterol (-20+/-4 mg/dL; all p<0.01). Both diet/exercise and pioglitazone improved Si (p<0.05), decreased total LDL particles (-227+/-40 and -149+/-21 nmol/L, respectively, both p<0.001) and small LDL particles (-242+/-58 and -226+/-36, respectively, both p<0.001). Large LDL particle concentrations increased with both treatments. LDL particle subclasses changes correlated with changes in Si only in the diet/exercise group.


CONCLUSIONS
In obese, insulin resistant non-diabetic adults, pioglitazone improved LDL particle characteristics in a manner similar to diet/exercise without changing TG, diabetic control, total or LDL cholesterol. This effect could have implications for atherosclerotic risk.
Shadid
Samyah
S
Endocrine Research Unit, 5-194 Joseph, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA.
LaForge
Ralph
R
Otvos
James D
JD
Jensen
Michael D
MD
D000328:Adult; D000704:Analysis of Variance; D001774:Blood Chemical Analysis; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008074:Lipoproteins / Q000737:chemistry*; D008297:Male; D019906:Nuclear Magnetic Resonance, Biomolecular; D009765:Obesity / Q000178:diet therapy* / Q000188:drug therapy / Q000628:therapy*; D010316:Particle Size; D000077205:Pioglitazone; D045162:Thiazolidinediones / Q000627:therapeutic use*; D015431:Weight Loss
D008074:Lipoproteins; D045162:Thiazolidinediones; D000077205:Pioglitazone