[Apolipoprotein E gene expression in peripheral blood monocyte in children with obesity].

Objective: Coronary heart disease (CHD) is one of the most common causes of death in the world. Some studies suggested that CHD begins in childhood. Obesity and dyslipidemia are important risk factors of coronary heart disease. Apolipoprotein (apo)E gene associated with dyslipidemia and coronary heart disease. The present study was designed to investigate the expression status of apoE gene in peripheral blood monocyte and association of apoE gene expression with lipids in children with obesity.

Methods: Among 32 children with obesity and 32 healthy children without obesity or overweight, ApoE gene expressions were determined by competitive reverse transcription-polymerase chain reaction in peripheral blood monocyte. The concentrations of plasma triglyceride, total cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol, lipoprotein(a), apoA I, apoB(100) and apoE were measured.

Results: Expression of apoE gene was detected in peripheral blood monocyte. Expression of apoE gene was significantly reduced in children with obesity as compared with control group (0.29 +/- 0.14 moles/mole GAPDH mRNA vs. 0.36 +/- 0.10 moles/mole GAPDH mRNA, t = 2.15, P < 0.05). The more severe was the degree of obesity, the more significantly reduced the expression of apoE gene; the degree of obesity was negatively correlated with the levels of expression of apoE gene (correlation coefficient = -0.40, P < 0.05). Compared with control group, the levels of triglyceride, total cholesterol, low density lipoprotein-cholesterol, and apoB(100) were higher, and those of high density lipoprotein-cholesterol, apoA I and apoE were lower in children with obesity [(1.68 +/- 0.50) mmol/L vs. (0.99 +/- 0.54) mmol/L, (4.47 +/- 0.91) mmol/L vs. (3.33 +/- 0.90) mmol/L, (2.23 +/- 0.71) mmol/L vs. (1.13 +/- 0.96) mmol/L, (94.48 +/- 9.97) mg/dl vs. (83.81 +/- 15.64) mg/dl, (1.47 +/- 0.39) mmol/L vs. (1.73 +/- 0.36) mmol/L, (112.71 +/- 27.86) mg/dl vs. (134.80 +/- 45.36) mg/dl, (24.50 +/- 10.92) mg/L vs.(35.07 +/- 9.79) mg/L, respectively, P < 0.05]. ApoE gene expression was associated with plasma lipids metabolism in children with obesity. The quantity of apoE gene expression was inversely associated with low density lipoprotein-cholesterol, positively correlated with apoE (correlation coefficient = -0.33, 0.35, respectively, P < 0.05). The quantity of apoE gene expression was not associated with total cholesterol, triglyceride, high density lipoprotein-cholesterol, lipoprotein(a), apoA I, and apoB(100) (correlation coefficient = -0.19, -0.11, 0.16, 0.09, 0.18, 0.22, P > 0.05).

Conclusion: Expression of apoE gene was significantly reduced in peripheral blood monocyte in children with obesity. The quantity of apoE gene expression was associated with degree of obesity and abnormality of blood lipids.