A Novel Immunoassay for Malondialdehyde-Conjugated Low-Density Lipoprotein Measures Dynamic Changes in the Blood of Patients Undergoing Coronary Artery Bypass Graft Surgery (original) (raw)
Related papers
Validation of a novel ELISA for measurement of MDA-LDL in human plasma
Free Radical Biology and Medicine, 2003
The involvement of oxidatively modified low density lipoprotein (LDL) in the development of CHD is widely described. We have produced two antibodies, recognizing the lipid oxidation product malondialdehyde (MDA) on whole LDL or ApoB-100. The antibodies were utilized in the development of an ELISA for quantitation of MDA-LDL in human plasma. Intra-and inter-assay coefficients of variation (% CV) were measured as 4.8 and 7.7%, respectively, and sensitivity of the assay as 0.04 g/ml MDA-LDL. Recovery of standard MDA-LDL from native LDL was 102%, indicating the ELISA to be specific with no interference from other biomolecules. Further validation of the ELISA was carried out against two established methods for measurement of lipid peroxidation products, MDA by HPLC and F 2 -isoprostanes by GC-MS. Results indicated that MDA-LDL is formed at a later stage of oxidation than either MDA or F 2 -isoprostanes. In vivo analysis demonstrated that the ELISA was able to determine steady-state concentrations of plasma MDA-LDL (an end marker of lipid peroxidation). A reference range of 34.3 Ϯ 8.8 g/ml MDA-LDL was established for healthy individuals. Further, the ELISA was used to show significantly increased plasma MDA-LDL levels in subjects with confirmed ischemic heart disease, and could therefore possibly be of benefit as a diagnostic tool for assessing CHD risk.
Clinical Biochemistry, 2000
Objectives: To develop a simple and practical enzyme immunoassay (EIA) for oxidatively modified low density lipoprotein (Ox-LDL) in human blood, a biological marker of atherogenesis. Design and methods: A sandwich EIA suitable for the measurement of human Ox-LDL was developed using the mouse monoclonal antibody FOH1a/DLH3. This antibody, specific for oxidized phosphatidylcholine, was used as the capture antibody, and a horseradish peroxidase (HRP)-labeled goat anti-human apolipoprotein-B (Apo-B) IgG was used for detection. Copper-oxidized human LDL, prepared under controlled conditions, was used as a standard and the results of the EIA were expressed in arbitrary units (U/mL). Results: This EIA meets all the requirements for use in routine clinical assays in terms of sensitivity (detection limit: 1 U/mL), reproducibility (total CV: 2.3-7.7%), accuracy (recovery: 90.6 -103.8%), simplicity and rapidity (Ͻ4 h). Clinical performance of the assay was assessed by measurement of the Ox-LDL in the plasma of normal subjects (10.8 Ϯ 2.8 U/mL, mean Ϯ SD) and patients with coronary heart disease (CHD) (19.7 Ϯ 10.2). The present EIA had a sensitivity of 79% and a specificity of 75% for CHD. Conclusions: We have developed a new assay, suitable for the measurement of Ox-LDL in human blood, which meets the requirements for routine clinical assay.
International Journal of Cardiology, 2013
Antibodies to oxidized low-density lipoproteins (oxLDLAbs) are detectable in the serum of patients with and without atherosclerosis, but it is unclear if they play a pathogenic or a protective role in atherogenesis or if they are simply a marker of atherosclerosis. Therefore, in a prospective cohort study we investigated if oxLDLAbs titer predicts cardiovascular (CV) events in high-risk coronary artery disease patients. Methods and results: The titer of IgG antibodies to malondialdehyde modified oxidized low-density lipoproteins was measured in 748 randomly selected patients of the GENICA study who underwent coronary angiography and assessment of incident CV events at follow-up. Patients were classified by oxLDLAbs into a low and a high titer group, corresponding to the first three and the last quartile, respectively. Cardiovascular event-free survival was compared between oxLDLAbs groups by Kaplan-Meier and multivariate technique including propensity score matching analysis. During long-term follow-up (median 7.2 years) CV deaths were observed in 65 patients (11.6%), more commonly in the high than in the low oxLDLAbs group (patients free from CV death 83.1% vs. 89% respectively, p = 0.025). The incidence of CV events was also higher in the former than in latter (event-free survival 69.2% vs. 77.7% respectively, p = 0.030). Conclusions: An oxLDLAbs titer above the 75th percentile is a marker of LDL oxidation which predicts a worse CV prognosis at long term follow-up in high-risk Caucasian patients referred for coronary angiography.
Antioxidants
We aimed to investigate if major vascular surgery induces LDL oxidation, and whether circulating antibodies against malondialdehyde-modified LDL (MDA-LDL) alter dynamically in this setting. We also questioned relationships between these biomarkers and post-operative cardiovascular events. Major surgery can induce an oxidative stress response. However, the role of the humoral immune system in clearance of oxidized LDL following such an insult is unknown. Plasma samples were obtained from a prospective cohort of 131 patients undergoing major non-cardiac vascular surgery, with samples obtained preoperatively and at 24- and 72 h postoperatively. Enzyme-linked immunoassays were developed to assess MDA-LDL-related antibodies and complexes. Adverse events were myocardial infarction (primary outcome), and a composite of unstable angina, stroke and all-cause mortality (secondary outcome). MDA-LDL significantly increased at 24 h post-operatively (p < 0.0001). Conversely, levels of IgG and ...
Resumos, 2003
The study included 79 patients with coronary artery disease (CAD), 25 individuals with preclinical atherosclerosis and 59 healthy individuals. Key lipid parameters were examined in all the participants. Levels of antibodies (Abs) (IgG and IgM) against low density lipoproteins (LDL) modified by malondialdehyde (MDA), acetic anhydride and hypochlorite, were determined by the enzyme-linked immunosorbent assay (ELISA). Abs specificity was tested by competitive ELISA. Circulating immune complexes (CIC) were isolated by polyethylene glycol precipitation followed by determination of their cholesterol by the enzymatic method. Abs to hypochlorite-modified LDL (hypochlorite-LDL) detected in the serum samples did not demonstrate cross-reactivity with MDA-modified LDL (MDA-LDL) and acetylated LDL (acetyl-LDL). Patients with CAD had increased levels of CIC (p < 0.0001) and decreased levels of Abs (IgM) to hypochlorite-LDL, compared with healthy controls and patients with preclinical atherosclerosis (p = 0.006
Auto-antibodies against oxidized low density lipoproteins in systemic diseases
Atherosclerosis, 1995
Oxidation of low density lipoproteins (LDL) obviously plays an important role in the pathogenesis of atherosclerosis. The purpose of the study was to determine whether antibodies against oxidized LDL are associated with coronary artery disease (CAD). We determined the serum levels of antibodies against copper-oxidized LDL by enzyme-linked immunosorbent assay in 58 patients with angiographically verified CAD and 34 controls without CAD. The mean antibody level, expressed in optical density units, was significantly higher in patients than in controls (0.150Ϯ0.088 versus 0.094Ϯ0.054, respectively; Pϭ0.00089). In logistic regression analysis, high antibody level against oxidized LDL was associated significantly with CAD (Pϭ0.0114), independent of age (Pϭ0.00137), gender (Pϭ0.0021), body mass index (Pϭ0.5947), triglyceride concentration (Pϭ0.9813), and total cholesterol-high density lipoprotein (HDL) cholesterol (Pϭ0.0080) group. Similar analysis in nondiabetic subjects (nϭ79) and in men only (nϭ75) showed analogous results, with only minor changes in P values. The antibody level against oxidized LDL differed significantly between nonsmokers and smokers in CAD patients (PϽ0.00197) but not in controls (PϭNS). In addition, the antibody level against oxidized LDL differed significantly between nonsmokers and smokers in subjects with low HDL cholesterol (Յ0.9 mmol/L) but not in subjects with high HDL cholesterol (Ͼ0.9 mmol/L). In conclusion, elevated levels of antibodies against oxidized LDL were associated with CAD. The data suggest that oxidized LDL plays a role in the pathogenesis of atherosclerosis and suggest a protective function for HDL against LDL oxidation.
A Rapid Method for Measurement of the Susceptibility to Oxidation of Low-Density Lipoprotein
Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 1995
Oxidation of low-density lipoprotein (LDL) may be important in the pathogenesis of atherosclerosis. We describe a method which measures the oxidation resistance of LDL isolated by a rapid procedure without added antioxidants. LDL was isolated from heparinized plasma by density gradient ultracentrifugation and desalted by gel filtration. The protein concentration was standardized to 50 mg/L and oxidation was promoted by copper (2 μmol/L) at 37°C. The total sample preparation time was 2·5 h. Conjugated diene production was monitored at λ = 234 nm with computation of the lag time. LDL oxidation was inhibited by EDTA but not heparin. Albumin inhibited LDL oxidation but only in concentrations greater than 50 mg/L. LDL was stable in frozen plasma (–70°C) for 10 weeks, but unstable in the isolated and desalted state. The lag time for LDL from patients treated with the antioxidant probucol was markedly prolonged compared to normal subjects.
2005
Antibody titer against malondialdehyde (MDA)-modified low-density lipoprotein (LDL) has been found to be associated with atherosclerosis, but it has not been established whether it would detect subjects with coronary artery disease (CAD). In the present study, receiver-operating characteristic (ROC) analysis was used to compare the diagnostic accuracy of the antibody titer against MDA-modified LDL and high-density lipoprotein (HDL) and LDL cholesterol levels in discrimination between subjects with (ns51) and without (ns35) angiographically verified 3-vessel CAD. As a result, the antibody titer against MDA-modified LDL was lower in subjects with CAD compared with subjects without CAD (p-0.0001). The area under the ROC plot was 0.822 (95% CI, 0.727 to 0.918) for the antibody titer and 0.769 (95% CI, 0.661 to 0.876) for the HDL cholesterol concentration. Both the antibody titer and the plasma HDL cholesterol level were more accurate markers of CAD than the LDL cholesterol level. As a conclusion, our results indicate that the antibody titer against MDA-modified LDL discriminates between subjects with widespread CAD and those without CAD similarly as the HDL cholesterol concentration. Moreover, the antibody titer against MDA-modified LDL is inversely correlated with the risk of severe CAD.