Analysis of polymorphisms in the 5'-flanking region of the apolipoprotein(a) [Apo(a)] gene in Thai subjects with coronary artery diseases.

Lipoprotein(a) [Lp(a)] is a complex lipoprotein particle in human plasma. It is composed of apolipoprotein B (Apo B)-100 and apolipoprotein(a) which are linked by a disulfide bond. Plasma levels of the Lp(a) vary greatly (over 1,000 folds) among individuals. Elevated plasma levels of the Lp(a) have been shown to be an independent risk factor for coronary artery diseases (CAD). The level of Lp(a) is controlled by a single gene, the Apo(a) gene, with multiple alleles; each encodes different concentrations of the Lp(a). Previous studies revealed the presence of polymorphisms in the 5'-flanking region (FL) of the Apo(a) gene at 3 positions: G or A (-914), C or T(-49), and G or A (-21), which can be detected by cleavage of PCR-amplified DNA products with TaqI, MaeII and HhaI, respectively. The 5'-FL genotypes of the Apo(a) gene can be classified by the combination of the presence (+) or absence (-) of these restriction sites into 5 types; type A, +++, type B, -++, type C, -+-, type D, --+ and type E, +-+. In the present study, the authors analyzed the 5' FL types of the Apo(a) gene by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) in 100 healthy control subjects, 26 CAD patients with [Lp(a)] < or = 30 mg/dL, and 94 CAD patients with [Lp(a)] > 30 mg/dL. The authors found that the genotype frequencies of the Apo(a) gene were 53, 16, 27 and 4%, for types A, B, C and D respectively in normal healthy controls. In CAD patients with [Lp(a)] < or = 30 mg/dL, the distribution of the genotype frequencies were 53.8, 11.5, 30.8 and 3.9% for types A, B, C and D, respectively. Additionally in CAD patients with [Lp(a)] > 30 mg/dL, the genotype frequencies were 60.6, 11.7, 21.3 and 6.4% for types A, B, C and D, respectively. The present study might shed some light to understand CAD at the molecular level.

Antioxidant status and lipid peroxidation end products in patients of type 1 diabetes mellitus.

BACKGROUND AND OBJECTIVE: In Type 1 diabetes mellitus (DM), hyperglycemia is considered a primary cause of diabetic vascular complications and is associated with oxidative stress. The role of antioxidants, particularly alpha tocopherol, in Type 1 DM and its contribution in the development of vascular complications is not clear. Therefore, the present study aims to investigate the relationship between antioxidant status (alpha tocopherol) and lipid peroxidation end products (malondialdehyde; MDA) in the plasma of 20 Type 1 DM and 20 nondiabetic healthy control subjects. MATERIAL AND METHOD: Lipid levels in all subjects were analyzed spectrophotometrically by enzymatic reagent kits. Plasma MDA was assessed by spectrofluorometry, whereas plasma alpha tocopherol was estimated by high performance liquid chromatography in Type 1 DM as well as in the control subjects of matched sex and ages. The results of Type 1 DM were compared with a control group using unpaired Student's t-test. The correlations between fasting plasma glucose and other laboratory parameters were assessed by Pearson rank correlation coefficient. RESULTS: The plasma MDA concentration was significantly higher in Type 1 diabetic patients as compared to controls, (p < 0.01). A significantly reduced plasma antioxidant status of Type 1 DM patients was found only in alpha tocopherol / total lipid as compared to controls (p < 0.05). However, no significant difference was observed in plasma a tocopherol and a tocopherol / total cholesterol (p > 0.05) as compared to the control subjects. The positive correlation between MDA and FPG was demonstrated in Type 1 diabetic compared with normal subjects. CONCLUSION: We conclude that antioxidant supplementation may be necessary for treatment to reduce oxidative stress for diabetic complication protection in Type 1 DM.