Increased apolipoprotein C-III levels associated with insulin resistance contribute to dyslipidemia in normoglycemic and diabetic subjects from a triethnic population

• Published in: Atherosclerosis 2006-09, Vol.188 (1), p.134-141
• Main Authors: Florez, Hermes, Mendez, Armando, Casanova-Romero, Paul, Larreal-Urdaneta, Carmen, Castillo-Florez, Sumaya, Lee, David, Goldberg, Ronald
• Format: Article
• Language: English
• Subjects: Adult; Aged; Apolipoprotein C-III; Apolipoprotein C-III - blood; Associated diseases and complications; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Cardiovascular Diseases - etiology; Coronary heart disease; Diabetes; Diabetes Mellitus, Type 2 - ethnology; Diabetes Mellitus, Type 2 - metabolism; Diabetes. Impaired glucose tolerance; Dyslipidemia; Dyslipidemias - ethnology; Dyslipidemias - metabolism; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Ethnic Groups; Female; Heart; Humans; Hypertriglyceridemia - ethnology; Hypertriglyceridemia - metabolism; Insulin Resistance; Lipoproteins, LDL - blood; Male; Medical sciences; Metabolic syndrome; Metabolic Syndrome - ethnology; Metabolic Syndrome - metabolism; Middle Aged; Particle Size; Risk Factors; Small-dense low-density lipoprotein; Triglycerides - blood
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2005.10.013

Despite the major role of insulin in regulating apolipoprotein C-III (apo C-III) production, little is known about the relationship between apo C-III and insulin resistance. We examined this relationship, and the association of apo C-III with dyslipidemia, in a triethnic sample of 168 subjects with normoglycemia or type 2 diabetes. African-Americans had lower triglycerides (1.21 ± 0.11 mmol/l) compared with Hispanics (2.01 ± 0.14 mmol/l) and white non-Hispanics (1.83 ± 0.15 mmol/l), regardless of gender and type 2 diabetes status ( P < 0.01), but this difference was partially accounted for by ethnic difference in apo C-III levels. Metabolic syndrome was associated with high apo C-III (>14 mg/dl) in Hispanics (OR = 5.6; 95%CI: 1.3–23.4) and white non-Hispanics (OR = 6.9; 95%CI: 1.3–36.4), but not in African-Americans. Apo C-III was the best predictor of triglycerides ( R 2 = 0.54, P < 0.001), after accounting for demographic and clinical variables. We found an inverse relationship between apo C-III levels and low-density lipoprotein (LDL) particle size in the type 2 diabetes subjects with ( r = −0.36, P = 0.02) and without ( r = −0.47, P = 0.02) the metabolic syndrome, but in normoglycemic subjects an inverse relationship was evident only in metabolic syndrome subjects ( r = −0.52, P < 0.01). These results suggest that higher apo C-III may contribute to the increased cardiovascular risk in subjects with insulin resistance and type 2 diabetes through its effects on triglycerides and LDL particle size.