Serum Malondialdehyde-Modified Low-Density Lipoprotein as a Risk Marker for Peripheral Arterial Stiffness in Maintenance Hemodialysis Patients.

Background and Objectives: Peripheral arterial stiffness (PAS), assessed by brachial-ankle pulse wave velocity (baPWV), is an independent biomarker of cardiovascular diseases (CVD) in patients on maintenance hemodialysis (HD). Malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidative stress marker, has been linked to atherosclerosis and CVD. However, the association between serum MDA-LDL and PAS among HD patients has not been fully elucidated. This study aimed to examine the association of serum MDA-LDL with PAS in HD patients and to identify the optimal cutoff value of serum MDA-LDL for predicting PAS. Materials and Methods: A cross-sectional study was conducted in 100 HD patients. Serum MDA-LDL was quantified using an enzyme-linked immunosorbent assay (ELISA), and baPWV was measured using a volume plethysmographic device. Patients were divided into the PAS group (baPWV > 18.0 m/s) and the non-PAS group (baPWV ≤ 18.0 m/s). The associations of baPWV and other clinical and biochemical parameters with serum MDA-LDL were assessed by multivariable logistic regression analyses. A receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff value of serum MDA-LDL for predicting PAS. Results: In multivariable logistic regression analysis, higher serum MDA-LDL, older age, and higher serum C-reactive protein [odds ratios (ORs) and 95% confidence intervals: 1.014 (1.004-1.025), 1.044 (1.004-1.085) and 3.697 (1.149-11.893)] were significantly associated with PAS. In the ROC curve analysis, the optimal cutoff value of MDA-LDL for predicting PAS was 80.91 mg/dL, with a sensitivity of 79.25% and a specificity of 59.57%. Conclusions: Greater serum MDA-LDL levels, particularly ≥80.91 mg/dL, were independently associated with PAS in HD patients. The findings suggest that oxidative stress plays a crucial role in the pathogenesis of PAS, and targeting MDA-LDL may be a potential therapeutic strategy for reducing cardiovascular risk in HD patients.

Lipid Peroxidation via Regulating the Metabolism of Docosahexaenoic Acid and Arachidonic Acid in Autistic Behavioral Symptoms.

The association between the lipid peroxidation product malondialdehyde (MDA)-modified low-density lipoprotein (MDA-LDL) and the pathophysiology of autism spectrum disorder (ASD) is unclear. This association was studied in 17 children with ASD and seven age-matched controls regarding autistic behaviors. Behavioral symptoms were assessed using the Aberrant Behavior Checklist (ABC). To compensate for the small sample size, adaptive Lasso was used to increase the likelihood of accurate prediction, and a coefficient of variation was calculated for suitable variable selection. Plasma MDA-LDL levels were significantly increased, and plasma SOD levels were significantly decreased in addition to significantly increased plasma docosahexaenoic acid (DHA) levels and significantly decreased plasma arachidonic acid (ARA) levels in the 17 subjects with ASD as compared with those of the seven healthy controls. The total ABC scores were significantly higher in the ASD group than in the control group. The results of multiple linear regression and adaptive Lasso analyses revealed an association between increased plasma DHA levels and decreased plasma ARA levels, which were significantly associated with total ABC score and increased plasma MDA-LDL levels. Therefore, an imbalance between plasma DHA and ARA levels induces ferroptosis via lipid peroxidation. Decreased levels of α-linolenic acid and γ-linolenic acid may be connected to the total ABC scores with regard to lipid peroxidation.

Lipid Peroxidation of the Docosahexaenoic Acid/Arachidonic Acid Ratio Relating to the Social Behaviors of Individuals with Autism Spectrum Disorder: The Relationship with Ferroptosis.

Polyunsaturated fatty acids (PUFAs) undergo lipid peroxidation and conversion into malondialdehyde (MDA). MDA reacts with acetaldehyde to form malondialdehyde-modified low-density lipoprotein (MDA-LDL). We studied unsettled issues in the association between MDA-LDL and the pathophysiology of ASD in 18 individuals with autism spectrum disorders (ASD) and eight age-matched controls. Social behaviors were assessed using the social responsiveness scale (SRS). To overcome the problem of using small samples, adaptive Lasso was used to enhance the interpretability accuracy, and a coefficient of variation was used for variable selections. Plasma levels of the MDA-LDL levels (91.00 ± 16.70 vs. 74.50 ± 18.88) and the DHA/arachidonic acid (ARA) ratio (0.57 ± 0.16 vs. 0.37 ± 0.07) were significantly higher and the superoxide dismutase levels were significantly lower in the ASD group than those in the control group. Total SRS scores in the ASD group were significantly higher than those in the control group. The unbeneficial DHA/ARA ratio induced ferroptosis via lipid peroxidation. Multiple linear regression analysis and adaptive Lasso revealed an association of the DHA/ARA ratio with total SRS scores and increased MDA-LDL levels in plasma, resulting in neuronal deficiencies. This unbeneficial DHA/ARA-ratio-induced ferroptosis contributes to autistic social behaviors and is available for therapy.

Simultaneous Electrochemical Detection of LDL and MDA-LDL Using Antibody-Ferrocene or Anthraquinone Conjugates Coated Magnetic Beads.

The simultaneous detection of atherosclerotic cardiovascular disease (ACSVD) biomarkers was recently of great scientific interest. In this work, magnetic beads-based immunosensors for the simultaneous detection of low density lipoprotein (LDL) and malondialdehyde-modified low density lipoprotein (MDA-LDL) were presented. The approach proposed was based on the formation of two types of specific immunoconjugates consisting of monoclonal antibodies: anti-LDL or anti-MDA-LDL, together with redox active molecules: ferrocene and anthraquinone, respectively, coated on magnetic beads (MBs). The decrease in redox agent current in the concentration range: 0.001-1.0 ng/mL for LDL and 0.01-10.0 ng/mL for MDA-LDL, registered by square wave voltammetry (SWV), was observed upon the creation of complex between LDL or MDA-LDL and appropriate immunoconjugates. The detection limits of 0.2 ng/mL for LDL and 0.1 ng/mL for MDA-LDL were estimated. Moreover, the results of selectivity against the possible interferents were good, as human serum albumin (HSA) and high density lipoprotein (HDL), stability and recovery studies demonstrated the potential of platform proposed for early prognosis and diagnosis of ASCVD.

Effect of febuxostat on the level of malondialdehyde-modified low-density lipoprotein, an oxidative stress marker: A subanalysis of the PRIZE study.

BACKGROUND: Febuxostat is a selective xanthine oxidase inhibitor that reportedly exhibits antioxidant properties. We previously performed a multicentre, randomized controlled (PRIZE) study for vascular evaluation under uric acid (UA) control by febuxostat to investigate the progression of carotid lesions in asymptomatic hyperuricemic patients with carotid atherosclerosis for 2 years. HYPOTHESIS: The current subanalysis of the PRIZE study aimed to assess the effect of febuxostat on the level of malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidative stress marker. METHODS: We recruited 383 patients (febuxostat group, n = 200; control group, n = 183) from the PRIZE trial for whom MDA-LDL measurements were available. The UA, MDA-LDL, low-density lipoprotein cholesterol (LDL-C) levels, and MDA-LDL/LDL-C ratio were identified, represented as the estimated difference from baseline to 24 months. We also evaluated the relationship between febuxostat dose (10, ≤20 to <40, and ≤40 to ≤60 mg) and changes in the MDA-LDL level, LDL-C level, or MDA-LDL/LDL-C ratios. RESULTS: The estimated change in MDA-LDL/LDL-C ratio from baseline to 24 months was significantly lower in the febuxostat group than in the control group (p = .025), whereas the estimated changes in MDA-LDL (p = .235) and LDL-C (p = .323) levels did not differ between the two groups. No significant correlation existed between the febuxostat doses and the estimated change in the MDA-LDL level (p = .626), LDL-C level (p = .896), or MDA-LDL/LDL-C ratio (p = .747). CONCLUSIONS: Our findings may indicate a possibility that febuxostat can lower the MDA-LDL/LDL-C ratio, a potential marker of atherosclerosis and oxidative stress, in asymptomatic hyperuricemic patients with carotid atherosclerosis. Further studies are required to validate our findings and elucidate the clinical antioxidant effect of febuxostat.

The Beneficial Effects of Astaxanthin on Glucose Metabolism and Modified Low-Density Lipoprotein in Healthy Volunteers and Subjects with Prediabetes.

Astaxanthin (ASTX) is an antioxidant agent. Recently, its use has been focused on the prevention of diabetes and atherosclerosis. We examined the effects of astaxanthin supplementation for 12 weeks on glucose metabolism, glycemic control, insulin sensitivity, lipid profiles and anthropometric indices in healthy volunteers including subjects with prediabetes with a randomized, placebo-controlled trial. METHODS: We enrolled 53 subjects who met our inclusion criteria and administered them with 12 mg astaxanthin or a placebo once daily for 12 weeks. Subsequently, their HbA1c levels, lipid profiles and biochemical parameters were determined. The participants also underwent a 75 g oral glucose tolerance test (OGTT), vascular endothelial function test and measurement of the visceral fat area. RESULTS: After astaxanthin supplementation for 12 weeks, glucose levels after 120 min in a 75 g OGTT significantly decreased compared to those before supplementation. Furthermore, the levels of HbA1c (5.64 ± 0.33 vs. 5.57 ± 0.39%, p < 0.05), apo E (4.43 ± 1.29 vs. 4.13 ± 1.24 mg/dL, p < 0.05) and malondialdehyde-modified low-density lipoprotein (87.3 ± 28.6 vs. 76.3 ± 24.6 U/L, p < 0.05) were also reduced, whereas total cholesterol (TC), triglyceride (TG) and high-density lipoprotein-C (HDL-C) levels were unaltered. The Matuda index, which is one of the parameters of insulin resistance, was improved in the ASTX group compared to that before supplementation. CONCLUSIONS: our results suggest that ASTX may have preventive effects against diabetes and atherosclerosis and may be a novel complementary treatment option for the prevention of diabetes in healthy volunteers, including subjects with prediabetes, without adverse effects.

B Cells in Atherosclerosis: Mechanisms and Potential Clinical Applications.

Because atherosclerotic cardiovascular disease is a leading cause of death worldwide, understanding inflammatory processes underpinning its pathology is critical. B cells have been implicated as a key immune cell type in regulating atherosclerosis. B-cell effects, mediated by antibodies and cytokines, are subset specific. In this review, we focus on elaborating mechanisms underlying subtype-specific roles of B cells in atherosclerosis and discuss available human data implicating B cells in atherosclerosis. We further discuss potential B cell-linked therapeutic approaches, including immunization and B cell-targeted biologics. Given recent evidence strongly supporting a role for B cells in human atherosclerosis and the expansion of immunomodulatory agents that affect B-cell biology in clinical use and clinical trials for other disorders, it is important that the cardiovascular field be cognizant of potential beneficial or untoward effects of modulating B-cell activity on atherosclerosis.

Additional Effect of Coronary High-Intensity Plaque on T1-Weighted Magnetic Resonance Imaging With Circulating Malondialdehyde-Modified Low-Density Lipoprotein on Cardiac Events.

BACKGROUND: Although elevated levels of oxidized low-density lipoprotein (LDL) could play a critical role in vulnerable plaque, there are no studies that have compared coronary high-intensity plaque (HIP) and circulating malondialdehyde-modified (MDA)-LDL levels for the prediction of cardiac events.Methods and Results:A total of 139 patients with coronary artery stenosis (>70%) were examined with non-contrast T1-weighted magnetic resonance imaging (MRI) (HIP: n=64, non-HIP: n=75). Scheduled percutaneous coronary intervention (PCI) for culprit lesions was performed within 48 h after MRI. HIP was defined as a signal intensity of coronary plaque to cardiac muscle ratio (PMR) ≥1.4. We evaluated the subsequent major adverse cardiac events (MACE) during the follow-up period (5.6±1.3 years). MDA-LDL levels were independently associated with the presence of HIP (P<0.0001). The incidence of MACE was 15%, and it was significantly higher in patients with HIP (27%) than in those without HIP (5%; P=0.011). Cox proportional hazard analysis showed MDA-LDL levels (P=0.007) and PMR (P=0.016) were significantly associated with MACE. For MACE prediction, C-statistic values for MDA-LDL, PMR, and PMR+MDA-LDL were 0.724, 0.791, and 0.800, respectively. Compared with MDA-LDL alone, the addition of PMR to MDA-LDL increased net reclassification improvement by 0.78 (P=0.012). CONCLUSIONS: MDA-LDL levels might be associated with the presence of HIP in patients with coronary artery disease. Furthermore, adding PMR to MDA-LDL levels markedly improved prediction of subsequent MACE after PCI.

Lipid Peroxidation With Implication of Organic Pollution in Autistic Behaviors.

Background Lipid metabolism has been associated with the development of autism. The omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) readily undergo lipid peroxidation and conversion to malondialdehyde (MDA). MDA-modified low-density lipoprotein (MDA-LDL) is a marker of lipid peroxidation. However, the association between PUFAs and MDA-LDL in the pathophysiology of autism spectrum disorder (ASD) is unclear. Materials and methods We studied the association between PUFAs and MDA-LDL in 16 individuals with ASD (mean age: 11.5 ± 5.7 years) and seven age- and sex-matched healthy controls (mean age: 10.0 ± 4.1 years). The Aberrant Behavior Checklist (ABC) was used to assess behavioral symptoms. We overcame the small sample size by using the adaptive LASSO for enhancing the accuracy of prediction and interpretability. We also estimated the coefficient of variation for an appropriate variable selection and compared additional prior studies to support the findings. Thus, we conducted a careful selection of appropriate candidates to account for confounding variables. Results The ASD group had significantly higher plasma MDA levels, eicosapentaenoic acid levels, and a higher ratio of plasma docosahexaenoic acid (DHA)/arachidonic acid (ARA) levels than the control group. Plasma levels of the omega-6 PUFA fraction, dihomo-γ-linolenic acid, and superoxide dismutase levels were significantly lower in the ASD group than in the control group. Total ABC scores were significantly higher in the ASD group than in the control group. Multiple linear regression and adaptive LASSO indicated that plasma DHA levels and plasma DHA/ARA ratios were significantly associated with total ABC scores and plasma levels of MDA-LDL. Conclusion Increased plasma levels of DHA and DHA/ARA ratio might be related to organic pollution. These neurobiological bases may induce neuronal deficiency associated with autistic behavioral symptoms in individuals with ASD.

Impact of malondialdehyde-modified low-density lipoprotein on clinical outcomes after fractional flow reserve-guided deferral of revascularization.

Cardiovascular events can occur after deferred revascularization, and malondialdehyde-modified low-density lipoprotein (MDA-LDL) has been suggested to be an atherogenic marker. We investigated the relationship between serum MDA-LDL levels and clinical outcomes in patients with fractional flow reserve (FFR)-guided deferral of revascularization. Among 3084 patients undergoing coronary angiography, we retrospectively analyzed 127 patients with intermediate stenosis and deferred revascularization based on FFR > 0.80. Median follow-up interval was 30.4 months, and serum MDA-LDL was measured prior to the measurement of FFR. We evaluated the composite of major adverse cardiac events (MACEs), including cardiac death, myocardial infarction, ischemia-driven deferred lesion revascularization, and any revascularization. MACEs occurred in 18 (14.2%) patients. The MACE group presented with significantly higher MDA-LDL levels than the non-MACE group (134.9 ± 33.3 U/L vs. 95.6 ± 32.2 U/L, P < 0.001). In analysis of the receiver operating characteristics curve for the prediction of MACEs, MDA-LDL presented a significantly larger area under the curve than low-density lipoprotein-cholesterol (LDL-C; 0.810 vs. 0.687, P = 0.042). Univariate Cox regression analysis indicated a significant relationship between MACEs and MDA-LDL (per 10 U/L, HR 1.20; P = 0.004), as did the multivariate model (per 10 U/L, HR 1.17; P = 0.019). When compared according to the median LDL-C (98 mg/dL), the MACE group had significantly higher MDA-LDL in both the high (147.2 ± 27.3 U/L vs. 113.9 ± 31.2 U/L, P = 0.001) and low (103.2 ± 27.3 U/L vs. 80.2 ± 24.0 U/L, P = 0.045) LDL-C groups. Serum MDA-LDL levels were associated with cardiac events in patients with deferral of revascularization based on FFR.

Increased Serum Malondialdehyde-Modified Low-Density Lipoprotein and Coronary Angiographic Progression After Drug-Eluting Stent Implantation in Patients With Stable Angina.

BACKGROUND: Cardiac events can occur after drug-eluting stent (DES) implantation due to coronary plaque progression at non-stented sites. Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is suggested to be an atherogenic marker. This study investigated the relationship between serum MDA-LDL and angiographic progression after DES implantation.Methods and Results:In total, 207 patients who underwent percutaneous coronary intervention (PCI) using DES and follow-up coronary angiography were retrospectively analyzed. MDA-LDL was serially measured before PCI and at follow up. Persistent high MDA-LDL was defined as a MDA-LDL level more than the median value both before PCI and at follow up. Angiographic progression was assessed by serial analysis of quantitative coronary angiography. Angiographic progression occurred in 35 patients (16.9%). MDA-LDL before PCI was significantly higher in the progression group than the non-progression group in all patients (143.4±35.8 U/L vs. 103.0±33.5U/L, P<0.001) and in patients with controlled LDL-cholesterol (LDL-C <100 mg/dL both before PCI and at follow up; 121.8±32.7 U/L vs. 84.9±24.9 U/L, P<0.001). There were positive correlations between % diameter stenosis changes and serum MDA-LDL before PCI in all patients (r=0.33, P<0.01) and those with controlled LDL-C (r=0.23, P=0.04). In multivariate logistic regression analysis, persistent high MDA-LDL was an independent predictor of plaque progression. CONCLUSIONS: Increased serum MDA-LDL was associated with angiographic progression after DES implantation.

The Association between the Triglyceride to High-density Lipoprotein Cholesterol Ratio and Low-density Lipoprotein Subclasses.

Objective The triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio is related to insulin resistance (IR). However, information about whether or not the TG/HDL-C ratio is associated with low-density lipoprotein (LDL) subclasses in the Japanese population is limited. Methods In total, 1,068 Japanese subjects who underwent an annual health examination and who were not taking medications were recruited. The association between the TG/HDL-C ratio and LDL subclasses was investigated using correlation, multiple regression, and receiver operating characteristic analyses. Results A correlation analysis revealed that both malondialdehyde-modified low-density lipoprotein (MDA-LDL) and small dense low-density lipoprotein cholesterol (sdLDL-C) were positively associated with the TG/HDL-C ratio. Furthermore, a multiple linear regression analysis revealed that the TG/HDL-C ratio was positively associated with MDA-LDL and sdLDL-C in both men and women. The multiple logistic regression analysis also revealed that the TG/HDL-C ratio was positively associated with the upper tertile of MDA-LDL and sdLDL-C in men and women. The LDL-C levels increased with the increasing TG/HDL-C ratio. The MDA-LDL and sdLDL-C are known to be positively associated with LDL-C. However, within the same LDL-C range, both MDA-LDL and sdLDL-C levels increased with the TG/HDL-C ratio, except for MDA-LDL levels in the LDL-C <112 mg/dL group in women. These results further supported the notion that the TG/HDL-C ratio was positively associated with the MDA-LDL and sdLDL-C levels, especially in the higher LDL-C range, in both men and women. The optimal cut-off points of the TG/HDL-C ratio for the upper tertile of MDA-LDL and sdLDL-C were 1.85 and 2.03 in men and 0.88 and 1.30 in women, respectively. Conclusion The TG/HDL-C ratio is positively associated with MDA-LDL and sdLDL-C in Japanese subjects. The relationship was particularly notable in subjects with high LDL-C levels.

The role of lipid peroxidation in individuals with autism spectrum disorders.

The role of malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidized LDL, in the pathophysiology of autism spectrum disorder (ASD) is unclear. We studied association between MDA-LDL and behavioral symptoms in 11 individuals with ASD and 7 age -matched normal controls. Behavioral symptoms were assessed using the Aberrant Behavior Checklists (ABC). Because small sample size in this study, three measures were conducted: first, employment of adaptive Lasso for enhancing the accuracy of prediction and interpretability; second, calculation of coefficient of variation for an appropriate selection of plasma variables; and third, selection of good candidates of plasma variables. Plasma levels of MDA-LDL, eicosapentaenoic acid, docosahexaenoic acid (DHA) and DHA/arachidonic acid ratios were significantly higher, while plasma superoxide dismutase (SOD) levels were significantly lower in the ASD group than in the control group. The total ABC scores were significantly higher in the ASD group than in the control group. Multiple linear regression analysis and the adaptive Lasso revealed association of increased plasma DHA levels with the ABC total scores and increased plasma MDA-LDL levels. Such association between DHA and plasma MDA-LDL levels may contribute to behavior in individuals with ASD.

Serum Malondialdehyde-Modified Low-Density Lipoprotein Is a Risk Factor for Central Arterial Stiffness in Maintenance Hemodialysis Patients.

Circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) acts as a marker of oxidative stress and is associated with atherosclerotic cardiovascular disease. The relationship between serum MDA-LDL levels and aortic stiffness (AS) in patients with hemodialysis (HD) was evaluated. There were 155 HD patients enrolled in this study. Carotid-femoral pulse wave velocity (cfPWV) was measured by a validated tonometry system. Patients with cfPWV >10 m/s were used to define the AS group, while those with values of ≤10 m/s were regarded as the control group. Serum MDA-LDL levels were measured using a commercial enzyme-linked immunosorbent assay. Sixty-eight patients (43.9%) who were defined as AS sufferers, and were older, had a higher percentage of diabetes and hypertension and higher systolic blood pressure and serum MDA-LDL level compared to subjects in the control group. After adjusting for factors significantly associated with AS by multivariable logistic regression analysis, it was revealed that serum MDA-LDL levels, diabetes, and hypertension were independent predictors of AS in HD patients. Multivariable forward stepwise linear regression analysis also showed that a logarithmically transformed MDA-LDL level was significantly correlated with cfPWV values in HD patients. In HD patients, a high serum MDA-LDL level was positively associated with cfPWV values and was a significant predictor of the development of high AS.

Add-on ezetimibe treatment to low-dose statins vs medium-intensity statin monotherapy in coronary artery disease patients with poorly controlled dyslipidemia.

Although ezetimibe has potential value as an add-on therapy to statins, it is not established whether the addition of ezetimibe to statin therapy is more effective than double-dose statin monotherapy. We conducted a crossover design study. Twenty-one coronary artery disease (CAD) patients whose lipid profiles had not achieved Japanese guideline recommendations (JAS 2017), despite receiving low-dose statin therapy, were divided into two groups. Group A received ezetimibe 10 mg in addition to the baseline dose of statin for the first 3 months and was then switched to monotherapy with a double dose of statin for the next 3 months. Group B first received a double dose of statin for 3 months and was then switched to ezetimibe 10 mg in addition to a baseline dose of statin for the next 3 months. Compared with the baseline, double-dose statin therapy reduced low-density lipoprotein (LDL)-cholesterol (from 118 ± 22 to 104 ± 15 mg/dL, P < 0.05) and malondialdehyde-modified LDL (MDA-LDL) (from 142 ± 35 to 126 ± 24 U/L, P < 0.05) but did not lower high-sensitivity C-reactive protein (hsCRP) (3.02 ± 0.47 and 2.98 ± 0.41 log [ng/ml]). The addition of ezetimibe to a baseline dose of statin further reduced LDL-cholesterol (to 89 ± 15, P < 0.0001) and MDA-LDL (to 114 ± 22 U/L, P < 0.001) and reduced hsCRP (to 2.78 ± 0.38 log (ng/ml), P < 0.05). The changes in the levels of MDA-LDL (R = 0.548, P = 0.010) and hsCRP (R = 0.473, P < 0.05) were significantly correlated with the change in the LDL-cholesterol level after the addition of ezetimibe. Add-on ezetimibe treatment appears superior to double-dose statin therapy in CAD patients with poorly controlled dyslipidemia in terms of reductions in LDL-cholesterol level, lipid peroxidation, and inflammation.

Malondialdehyde-modified LDL-related variables are associated with diabetic kidney disease in type 2 diabetes.

BACKGROUND AND AIMS: Oxidized low-density lipoprotein (oxLDL) causes the development of atherosclerosis and kidney injury. Although circulating oxLDL levels were reportedly increased in type 2 diabetic patients with macroalbuminuria, it remains unclear whether albuminuria or the reduced glomerular filtration rate (GFR) is independently associated with the circulating oxLDL level. This study aimed to elucidate the association between the stage of diabetic nephropathy and serum malondialdehyde-modified LDL (MDA-LDL) and the ratio of MDA-LDL to LDL-cholesterol (MDA-LDL/LDL). METHODS AND RESULTS: This retroactive cross-sectional study used data from 402 patients with type 2 diabetes. Patients undergoing hemodialysis were excluded. Serum MDA-LDL levels were significantly increased with increases in severity of albuminuria (103 ±â€¯44 U/L, 109 ±â€¯54 U/L, and 135 ±â€¯72 U/L for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.020) but not according to the estimated GFR (eGFR). An increased MDA-LDL/LDL ratio was significantly associated with both increased albuminuria (35 ±â€¯13, 37 ±â€¯14, and 40 ±â€¯15 for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.003) and reduced eGFR (34 ±â€¯13, 36 ±â€¯13, 38 ±â€¯12, and 51 ±â€¯28 for grade 1, 2, 3 and 4, respectively; P for trend = 0.002). Multiple linear regression analysis showed that neither the albumin excretion rate nor eGFR but ln-transformed triglycerides and LDL-C levels were independent determinants of both serum MDA-LDL levels and MDA-LDL/LDL ratios. CONCLUSION: Serum MDA-LDL levels and MDA-LDL/LDL ratios were increased in those with dyslipidemia associated with diabetic kidney disease.

Impact of malondialdehyde-modified low-density lipoprotein on coronary plaque vulnerability in patients not receiving lipid-lowering therapy: a whole coronary analysis with multislice-computed tomography.

Vulnerable plaque disruption was suggested as a primary cause of acute coronary syndrome. This study investigated the impact of malondialdehyde-modified low-density lipoprotein (MDA-LDL) on whole coronary plaque vulnerability, based on multislice-computed tomography (MSCT). We included 197 patients that were not receiving lipid-lowering therapy. We retrospectively analyzed MSCT and MDA-LDL measurements. We defined a CT-derived vulnerable plaque as a plaque with a remodeling index > 1.10 and a mean CT density value < 30 HU. Vulnerable plaques were detected in 60 patients (30%). Patients with vulnerable plaques had significantly higher MDA-LDL levels than patients without vulnerable plaques (151.3 ± 42.3 vs. 118.5 ± 41.7 U/L, p < 0.01). A univariate regression analysis showed that vulnerable plaques were significantly related to MDA-LDL levels [10 U/L groups, odds ratio (OR): 1.19; p < 0.01] and in a multivariate model (10 U/L groups, OR: 1.18; p < 0.01). Patients with multivessel vulnerable plaques had significantly higher MDA-LDL levels than those with single-vessel involvement or no vulnerable plaque (172.4 ± 28.5 vs. 142.8 ± 44.2 vs. 118.5 ± 41.7 U/L, respectively; p < 0.01). MDA-LDL difference was observed for all LDL tertiles (bottom; 128.9 ± 41.1 vs. 97.3 ± 25.0 U/L, p < 0.01, middle; 142.6 ± 42.7 vs. 122.5 ± 35.1 U/L, p = 0.05, top; 166.0 ± 38.1 vs. 143.5 ± 51.6 U/L, p = 0.05). Increased MDA-LDL levels were associated with the presence and extent of vulnerable plaques, regardless of LDL levels.

SYK regulates macrophage MHC-II expression via activation of autophagy in response to oxidized LDL.

Adaptive immunity, which plays an important role in the development of atherosclerosis, is mediated by major histocompatibility complex (MHC)-dependent antigen presentation. In atherosclerotic lesions, macrophages constitute an important class of antigen-presenting cells that activate adaptive immune responses to oxidized low-density lipoprotein (OxLDL). It has been reported that autophagy regulates adaptive immune responses by enhancing antigen presentation to MHC class II (MHC-II). In a previous study, we have demonstrated that SYK (spleen tyrosine kinase) regulates generation of reactive oxygen species (ROS) and activation of MAPK8/JNK1 in macrophages. Because ROS and MAPK8 are known to regulate autophagy, in this study we investigated the role of SYK in autophagy, MHC-II expression and adaptive immune response to OxLDL. We demonstrate that OxLDL induces autophagosome formation, MHC-II expression, and phosphorylation of SYK in macrophages. Gene knockout and pharmacological inhibitors of NOX2 and MAPK8 reduced OxLDL-induced autophagy. Using bone marrow-derived macrophages isolated from wild-type and myeloid-specific SYK knockout mice, we demonstrate that SYK regulates OxLDL-induced ROS generation, MAPK8 activation, BECN1-BCL2 dissociation, autophagosome formation and presentation of OxLDL-derived antigens to CD4(+) T cells. ldlr(-/-) syk(-/-) mice fed a high-fat diet produced lower levels of IgG to malondialdehyde (MDA)-LDL, malondialdehyde-acetaldehyde (MAA)-LDL, and OxLDL compared to ldlr(-/-) mice. These results provide new insights into the mechanisms by which SYK regulates MHC-II expression via autophagy in macrophages and may contribute to regulation of adaptive immune responses in atherosclerosis.

Increased circulating malondialdehyde-modified low-density lipoprotein levels in patients with ergonovine-induced coronary artery spasm.

OBJECTIVE: Coronary endothelial dysfunction is thought to underlie the development of coronary artery spasms. Malondialdehyde-modified low-density lipoprotein (MDA-LDL) was suggested as a marker of endothelial damage. This study investigated the diagnostic impact of MDA-LDL on ergonovine-induced coronary spasms. METHODS: We included 152 patients with suspected coronary spastic angina. MDA-LDL levels were measured before an ergonovine provocation test. Coronary spasm was defined as total or subtotal occlusion, compared to the relaxed state after nitroglycerin, associated with ischemic ECG changes and concurrent chest pain. Changes in vessel diameter in response to ergonovine were evaluated with quantitative coronary angiography. RESULTS: Coronary spasms were observed in 41 patients (27%). MDA-LDL levels were significantly higher in patients with spasms compared to those without spasms (139.9 ± 45.9 U/L vs. 109.6 ± 36.6 U/L, p<0.01). Univariate logistic regression analyses indicated significant relationships between coronary spasms and MDA-LDL (per 10 U/L, odds ratio (OR): 1.20; p<0.01), high-density lipoprotein (per 10 mg/dL, OR: 0.76; p=0.03), smoking (OR: 3.04; p<0.01), and male gender (OR: 3.51; p<0.01). In the multivariate model, MDA-LDL (per 10 U/L, OR: 1.17; p<0.01) remained a significant predictor of coronary spasm. Regression analysis showed a positive correlation between MDA-LDL levels and coronary luminal diameter changes induced by ergonovine (r=0.57, p<0.01). The optimal MDA-LDL threshold for predicting coronary spasm was 121.3 U/L, identified with a receiver operating characteristic curve. CONCLUSIONS: Increased circulating MDA-LDL levels were associated with ergonovine-induced coronary artery spasm.

Malondialdehyde-modified low-density lipoprotein is a predictor of cardiac events in patients with stable angina on lipid-lowering therapy after percutaneous coronary intervention using drug-eluting stent.

OBJECTIVE: Patients undergoing lipid-lowering therapy after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) are subject to residual risk. Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is suggested as a marker of the initiation and acceleration of atherosclerosis. This study aimed to investigate the impact of MDA-LDL on clinical outcomes in patients with stable angina undergoing lipid-lowering therapy after DES implantation. METHODS: In this study, 332 patients whose MDA-LDL was measured before PCI with DES were followed clinically (median 2.9 years). Lipid-lowering therapy was conducted, with the target LDL ≤100 mg/dL. We analyzed the composite of major adverse cardiac events (MACE), including cardiac death, myocardial infarction, stent thrombosis, ischemia-driven target lesion revascularization, and any revascularization. RESULTS: MACE was observed in 64 patients (19.3%). MDA-LDL was significantly higher in the MACE group (139.1 ± 53.2U/L vs. 106.5 ± 38.3U/L, p < 0.01). Univariate Cox regression analysis indicated a significant relationship between MACE and hemodialysis (Hazard ratio (HR) 4.60; p < 0.01), MDA-LDL (per 10U/L, HR 1.14; p < 0.01), multivessel disease (HR 1.78; p = 0.02), and high-density lipoprotein (per 10 mg/dL, HR 0.79; p = 0.03). In the multivariate model, hemodialysis (HR 4.10; p < 0.01) and MDA-LDL (per 10U/L, HR 1.10; p < 0.01) remained significant predictors of MACE. The optimal MDA-LDL threshold for predicting MACE was 114.1U/L, identified by the receiver operating characteristic curve. CONCLUSIONS: MDA-LDL was associated with future cardiac events in patients with stable angina that underwent lipid-lowering therapy after DES-PCI.