Search

Background: Previous studies have suggested that hypertension may be associated with increased oxidized low-density lipoprotein (LDL). Increased in vitro oxidizability of LDL or elevated titers of anti-oxidized LDL antibodies have been shown in subjects with essential hypertension. However, the relationship between oxidized LDL and hypertension is equivocal. We examined the association between hypertension and levels of IgG anti-oxidized LDL antibodies in a group of women from the general population., Materials and Methods: The study included 619 women classified according to their blood pressure values. IgG anti-oxidized LDL antibodies were measured by enzyme-linked immunosorbent assay and the women were classified as being above or below the 50th percentile., Results: Hypertension was present in 54.3% of the women. These women had significantly lower levels of IgG anti-oxidized LDL antibodies than the normotensive women (0.280 +/- 0.117 vs. 0.336 +/- 0.125, P < 0.001). Both systolic and the diastolic blood pressures showed a significant negative correlation with the levels of IgG anti-oxidized LDL antibodies (r = -0.204, P < 0.001; r = -0.225, P < 0.001, respectively). Women with IgG anti-oxidized LDL antibody levels above the 50th percentile had a lower prevalence of hypertension than those with IgG anti-oxidized LDL antibody levels below the 50th percentile (40.2% vs. 59.8%) (P < 0.001)., Conclusions: Women with hypertension had lower levels of IgG anti-oxidized LDL antibodies than normotensive women.

Background: Anti-oxidized low-density lipoprotein (LDL) antibodies are associated with the oxidative capacity of plasma, but whether they protect or promote diabetes is unknown. We undertook a prospective study to determine the predictive capacity of anti-oxidized LDL antibodies for the onset of type 2 diabetes mellitus (T2DM)., Materials and Methods: We selected 391 non-diabetic women aged 18-65 years. The subjects were classified as being normal (oral glucose test tolerance normal, OGTT-N), or having impaired glucose tolerance (IGT), impaired fasting glucose (IFG) or T2DM according to their baseline glucose levels and after an OGTT. The same subjects were studied six years later. The levels of anti-oxidized LDL antibodies were classified as above or below the 50th percentile., Results: Of the women who were OGTT-N at the start of the study and who had anti-oxidized LDL antibody levels below the 50th percentile, only 65.1% were still OGTT-N after 6 years versus 79.5% of those who had anti-oxidized LDL antibody levels above the 50th percentile (P = 0.015). Women who had IGT or IFG at the start of the study whose anti-oxidized LDL antibody levels were below the 50th percentile had a relative risk of 9.79 (95% confidence interval, 1.40-68.45) of developing diabetes (P < 0.001). Logistic regression analysis showed that the variables predicting the development of a carbohydrate metabolism disorder in the women after 6 years were body mass index (P < 0.001) and the levels of anti-oxidized LDL antibodies (P = 0.042)., Conclusions: Levels of anti-oxidized LDL antibodies are independent predictors for the development of T2DM in women.

Oxidative modification of LDL is thought to play an important role in the development of atherosclerosis. Susceptibility of LDL to peroxidation may partly depend on the compositional characteristics of the antioxidant and fatty acid content. The aim of this study was to examine the association between levels of antibodies to oxidized LDL and the various serum fatty acids in women. A total of 465 women aged 18-65 years were selected randomly from the adult population census of Pizarra, a town in southern Spain. Measurement of anti-oxidized-LDL was done by ELISA and the fatty acid composition of serum phospholipids was determined by GC. The levels of anti-oxidized-LDL antibodies were significantly related with age (r - 0.341, P < 0.001), BMI (r - 0.239, P < 0.001), waist:hip ratio (r - 0.285, P < 0.001), glucose (r - 0.208, P < 0.001), cholesterol (r - 0.243, P < 0.001), LDL-cholesterol (r - 0.185, P = 0.002), EPA (r - 0.159, P = 0.003), DHA (r - 0.121, P = 0.026), and the sum of the serum phospholipid n-3 PUFA (r - 0.141, P = 0.009). Multiple regression analysis showed that the variables that explained the behaviour of the levels of anti-oxidized-LDL antibodies were age (P < 0.001) and the serum phospholipid EPA (P < 0.001). This study showed that the fatty acid composition of serum phospholipids, and especially the percentage of EPA, was inversely related with the levels of anti-oxidized-LDL antibodies.

Objective: Several different epidemiological studies have examined the association between the consumption of tea and coronary heart disease. Some, though not all, support the view that tea or flavonoids reduce the risk of cardiovascular heart disease. The aim of this study was to determine the short-to medium-term effect of a green tea extract on vascular function and lipid peroxidation as compared with placebo., Methods: The study was undertaken with 14 healthy women, none of whom were receiving any medical treatment. Measurements were made of antibodies and immune complexes by ELISA, endothelial dependent vascular function by Doppler ultrasound, and the concentration of oxidized LDL by TBARS., Results: The mean diameter of the brachial artery following the post-compression hyperaemia phase rose significantly (p < 0.0001) after treatment with green tea extract. Flow-mediated brachial artery vasodilation ranged from 5.68% for the placebo phase to 11.98% after the green tea extract (p = 0.02). The consumption of green tea extract was associated with a significant 37.4% reduction in the concentration of oxidized LDL (TBARS) (p = 0.017). The levels of anti-oxidized LDL IgM antibodies fell significantly after treatment (p = 0.002)., Conclusion: This study found that consumption of green tea extract by women for five weeks produced modifications in vascular function and an important decrease in serum oxidizability.

Recent studies suggest that the biological effects of saturated fatty acids depend on the length of their chain. We compared the effect of diets containing different fatty acids on plasma lipids and lymphocyte proliferation in the presence of lovastatin and with increasing amounts of LDL. Lymphocytes from rats fed with a diet rich in palmitic acid had a greater lymphocyte proliferation capacity than those from rats fed with diets rich in oleic acid, linoleic acid, or fish oil. This effect was maintained when small amounts of polyunsaturatwed fatty acids (PUFA; sunflower oil) were added to the palmitic acid diet. LDL receptor activity, measured by the capacity of lovastatin to revert the inhibition of lymphocyte proliferation with increasing amounts of LDL in the medium, was greater in the rats fed with palmitic acid, and was similar to the other groups when small amounts of PUFA were added. All the groups had similar levels of plasma cholesterol, but the LDL levels were significantly lower in the group fed with palmitic acid plus PUFA. The highest HDL-cholesterol (HDLc) levels were found in the palmitic acid group and the lowest LDL-cholesterol (LDLc)/HDLc ratio in the palmitic acid plus PUFA group. These results suggest that diets rich in palmitic acid do not raise total cholesterol, but reduce LDLc or keep it normal, and raise HDLc levels. This effect may be partly due to an increase in LDL receptor activity. The inclusion of small amounts of PUFA in the diet rich in palmitic acid substantially modified the LDL receptor response in the lymphocytes, suggesting that the proportion of different families of dietary fatty acids may be more important than the individual amount of each in absolute terms to explain their effects on plasma lipids and lipoproteins.

Objectives: To study the levels of anti-oxidized low-density lipoprotein (LDL) antibodies in patients with systemic lupus erythematosus (SLE) at two different points during the disease, and evaluate their relation with markers of SLE activity in serial blood samples. To investigate the correlations at two points in time between anti-oxidized LDL antibodies and anti-beta2-glycoprotein-I antibodies, leucocytes, immunoglobulin G, anti-deoxyribonucleic acid, complement 3, complement 4 and the disease activity index., Methods: A total of 49 patients with SLE according to ACR criteria were studied at two points, 3 to 4 months apart, Time 1 and Time 2., Results: There were ostensible changes in levels of anti-oxidized LDL antibodies between Times 1 and 2, which correlated significantly with disease activity markers. The association between levels of anti-oxidized LDL antibodies and complement system activation remained after multiple regression analysis with stepwise adjustment., Conclusions: Antibody levels against oxidized LDL vary with time and are closely related to the degree of SLE activity. There is an association between levels of autoantibodies to oxidized LDL and complement system activation.

Autoantibodies against epitopes of oxidized low-density lipoprotein (LDL), initially shown in human sera, were later related with the atherosclerotic process, although recent studies have questioned this association. Moreover, their association with total cholesterol and plasma LDL, or with the other lipoproteins, is not clear. We studied the relation between the levels of autoantibodies to oxidized LDL and lipoproteins in a population of 400 subjects from the lower Guadalhorce area in Malaga, Spain. Anti-oxidized LDL antibodies were measured by enzyme-linked immunosorbent assay (ELISA), and total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and lipoprotein(a) [Lp(a)] were measured with commercial kits. Subjects who were positive for anti-oxidized LDL antibodies had significantly lower levels of total cholesterol (P <.01) and LDL cholesterol (P <.01). There was a negative correlation between titers of anti-oxidized LDL antibodies and levels of total cholesterol (P =.007) and LDL cholesterol (P =.024). This inverse relation between the levels of anti-oxidized LDL antibodies and the levels of total cholesterol and LDL cholesterol in a large population study, together with the discordances already published, suggests that the relation between anti-oxidized LDL antibodies, arteriosclerosis, and lipids is more complex than initially thought., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Objective: To investigate whether circulating concentrations of antibodies against oxidized low-density lipoproteins (LDL) are increased in patients with systemic sclerosis (SSc)., Methods: Oxidation of LDL and anti-oxidized LDL antibodies were measured in 26 patients with limited cutaneous SSc (LCSSc), in eight patients with diffuse cutaneous SSc (DCSSc) and in 24 healthy control subjects. Results were adjusted for age, sex and smoking., Results: Binding to oxidized LDL was increased in patients with both limited and diffuse cutaneous disease (geometric mean 0.35 and 0.39 optical density units respectively) compared with controls (0.28) (P=0.03 and P=0.01 respectively). Circulating concentrations of anti-oxidized LDL were increased only in patients with diffuse SSc (geometric mean 0.22 optical density units) compared with controls (geometric mean 0.16, P=0.02)., Conclusion: These preliminary findings lend further weight to the concept that oxidation of LDL contributes to the vascular pathology of SSc, particularly in patients with diffuse cutaneous disease. Prospective longitudinal studies are required to investigate whether anti-oxidized LDL antibodies may be a marker of vascular damage in SSC.

The prevalence and clinical significance of antibodies against beta2-glycoprotein I (anti-beta2GPI) and antibodies against oxidized low-density lipoprotein (anti-ox-LDL) were evaluated as potential indicators of arterial disease in patients with systemic lupus erythematosus (SLE) and SLE with secondary antiphospholipid syndrome (APS). IgG anti-beta2GPI and IgG anti-ox-LDL were measured by enzyme-linked immunosorbent assay (ELISA) in serum samples from 118 patients with SLE, including 40 with secondary APS. IgG anti-beta2GPI were positive in 17% (20/118) of SLE patients. The presence and titres of IgG anti-beta2GPI were strongly associated with a history of arterial thrombosis. Haemolytic anaemia was also significantly associated with the presence of IgG anti-beta2GPI. The prevalence of IgG anti-ox-LDL was 53% (63/118), but there was no association with arterial thrombosis. No correlation between the values of anti-ox-LDL and those of anti-beta2GPI was found. These results suggest that IgG anti-beta2GPI could be a marker for arterial thrombosis in SLE patients, while IgG anti-ox-LDL were not associated with arterial disease in this group of lupus patients.

Previous studies have shown a cross-reaction between anticardiolipin and anti-oxidized low-density lipoprotein (LDL) antibodies in patients with the antiphospholipid syndrome (APS). The aim was to investigate the existence of a cross-reaction between anti-beta2-glycoprotein-I (beta2-GP-I) and anti-oxidized LDL antibodies in a group of APS patients. Ninety-three patients with APS were included in the study; 47 of these patients were diagnosed as primary APS, while the rest (46 patients) fulfilled criteria for the classification of systemic lupus erythematosus (SLE). All patients were positive for the IgG isotype of anticardiolipin antibodies (aCL). Twelve (26%) SLE-associated APS and 14 (29.7%) primary APS patients had raised concentrations of IgG antibodies to oxidized LDL. There was no correlation between anti-beta2-GP-I and anti-oxidized LDL antibodies. Inhibition experiments showed no cross-reaction either between anti-beta2-GP-I and anti-oxidized LDL antibodies, or between anti-beta2-GP-I and anti-native LDL antibodies. Our study suggests that the presence of both anti-beta2-GP-I and anti-oxidized LDL antibodies in patients with APS is not due to the structural similarity and consequent cross-reaction, and that they are two different populations of antibodies directed against different antigens.