Malondialdehyde-Modified Low-Density Lipoprotein as a Predictor of Major Adverse Limb Events after Endovascular Therapy in Patients with Lower Extremity Arterial Disease

AIM

Adverse limb events after endovascular therapy (EVT) are a major concern. This study aimed to investigate the relationship between serum malondialdehyde-modified low-density lipoprotein (MDA-LDL) level, a potentially potent indicator of atherosclerosis, and clinical outcomes after EVT in patients with lower extremity arterial disease (LEAD).

METHODS

A total of 208 LEAD patients who underwent EVT and MDA-LDL measurements were retrospectively analyzed. Those with chronic limb-threatening ischemia (CLTI) were included in the CLTI subgroup (n=106). Patients were further categorized into the High or Low MDA-LDL groups according to the cut-off value calculated by receiver operating characteristic analysis. Major adverse limb events (MALE), a composite of cardiovascular death, limb-related death, major amputation, and target-limb revascularization, were evaluated.

RESULTS

MALE occurred in 73 (35%) patients. The median follow-up interval was 17.4 months. The MDA-LDL cut-off values were 100.5 U/L (area under the curve [AUC] 0.651) in the overall population and 98.0 U/L (AUC 0.724) in the CLTI subgroup. Overall, the High MDA-LDL group showed significantly higher total cholesterol (189.7±37.5 mg/dL vs. 159.3±32.0 mg/dL, p＜0.01), low-density lipoprotein cholesterol (114.3±29.7 mg/dL vs. 87.3±25.3 mg/dL, p＜0.01), and triglyceride (166.9±91.1 mg/dL vs. 115.8±52.3 mg/dL, p＜0.01) than the Low MDA-LDL group. Multivariate Cox regression analyses revealed that MDA-LDL and C-reactive protein were independent predictors of MALE. In the CLTI subgroup, MDA-LDL was an independent predictor of MALE. The High MDA-LDL group showed worse MALE-free survival rates than the Low MDA-LDL group in overall (p＜0.01) and in the CLTI subgroup (p=0.01).

CONCLUSIONS

Serum MDA-LDL level was associated with MALE after EVT.

Increase in oxidized low-density lipoprotein level according to hyperglycemia in patients with cardiovascular disease: A study by structure equation modeling

AIMS

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) level has been reported to be strongly associated with the pathogenesis of cardiovascular diseases. We focused on diabetic status and investigated its possible contribution to MDA-LDL level.

METHODS

The study sample consisted of 2705 patients who were admitted to our hospital and underwent cardiac catheterization. Blood samples were obtained to measure the levels of fasting blood sugar (FBS), hemoglobin A1c (HbA1c), insulin, LDL, MDA-LDL and others. Body mass index (BMI) was also used in constructing structural equation modeling and Bayesian estimation.

RESULTS

To explore the factors theoretically associated with MDA-LDL level, we performed structural equation modeling. We generated a path model that revealed that BMI, LDL level and FBS were significantly associated with MDA-LDL level (P < 0.001 for each factor), whereas insulin level and HbA1c level were not significantly associated (P = NS for both factors). Noted above was clearly demonstrated on the image of 2-D contour line by Bayesian structure equation modeling.

CONCLUSIONS

This study clearly showed that hyperglycemia affects MDA-LDL level. An interaction between diabetes and dyslipidemia was shown in terms of activation of lipid oxidation.

Circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) as a novel predictor of clinical outcome after endovascular therapy in patients with peripheral artery disease (PAD)

BACKGROUND AND AIMS

Despite advances in the treatment of peripheral artery disease (PAD), cardiovascular events and death rates remain high. This study aimed at identifying markers of outcome in patients with PAD undergoing endovascular therapy (EVT).

METHODS

Consecutive patients undergoing EVT were recruited. Markers of oxidative stress (malondialdehyde-modified low-density lipoprotein [MDA-LDL]), inflammation (IL-6; high-sensitivity C-reactive protein [hsCRP]) and fibrinolysis (D-dimer) were measured pre-EVT and at post-EVT time-points to 36 h. Clinical follow-up assessed major cardiovascular and/or limb events.

RESULTS

In the 35 patients enrolled, mean MDA-LDL levels decreased from a baseline level of 106.2 U/L to 72.6 U/L immediately post-EVT (p<0.0001); levels remained significantly reduced at all time-points. IL-6, hsCRP and D-dimer increased and were significantly higher at the 36 h time-point. A significant, negative association was seen between decreased MDA-LDL and pre-EVT hsCRP levels (r = -0.42, p=0.012). Clinical follow-up data were obtained for a mean period of 16 months. MDA-LDL ratios (obtained by comparison of post- and pre-EVT values) allowed assessment of high (≥0.495) and low (<0.495) ratio groups. A significantly higher rate of major adverse events, including limb-related events or death, was seen in the low ratio group (p<0.001). Cox proportional hazard analysis including traditional risk factors indicated that this ratio is a significant predictor of clinical endpoints (HR = 0.4210, p=0.0154). An association with clinical outcome was not observed with the other candidate biomarkers.

CONCLUSIONS

Assessment of pre- and post-EVT MDA-LDL levels is a promising marker of clinical outcome in patients with PAD.

High levels of AGE-LDL, and of IgG antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL in circulating immune complexes predict macroalbuminuria in patients with type 2 diabetes

BACKGROUND

Circulating immune complexes (IC) containing modified forms of LDL (mLDL) are strongly pro-inflammatory and when present in high levels are associated with the development of diabetic complications.

OBJECTIVE

We investigated whether levels of oxidized LDL (oxLDL), malondialdehyde-LDL (MDA-LDL) and advanced glycation end products-LDL (AGE-LDL) as well as IgG and IgM antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL isolated from circulating IC were associated with progression to macroalbuminuria in type 2 diabetes (VADT cohort).

METHODS

Levels of mLDL in IC were measured in 905 patients, a median of two years after entry into the study. Participants were followed for an average of 3.7years for renal outcomes. Generalized logistic regression models were used to quantify the association of increased levels of biomarkers and development of abnormal albuminuria. Normal, persistent micro- (ACR ≥30), incident micro- (ACR ≥30) and incident macroalbuminuria (ACR ≥300) were the outcomes of interest.

RESULTS AND CONCLUSIONS

Patients with macro (n=78) or non-persistent microalbuminuria (n=81) at baseline were excluded. Odds ratios for endpoints in relation to high versus low (defined using a median split) biomarker levels are found in Fig. 1. Our study demonstrates that high levels of AGE-LDL as well as of IgG antibodies (but not IgM antibodies) reacting with MDA-LDL lysine epitopes in circulating IC predict the development of macroalbuminuria in patients with type 2 diabetes. These data support the pathogenic role of modified LDL IgG antibodies but not the protective role of modified LDL IgM antibodies.

Optimal serum phenylalanine for adult patients with phenylketonuria

High serum phenylalanine in adult patients with phenylketonuria (PKU) causes neuropsychological and psychosocial problems that can be resolved by phenylalanine-restricted diet. Therefore, PKU patients must continue to adhere to phenylalanine-restricted diet for life, although the optimal serum phenylalanine level in later life has yet to be established. The purpose of this review was to establish the optimal serum phenylalanine level in later life of PKU patients. We evaluated oxidative stress status, nitric oxide metabolism, cholesterol-derived oxysterols, vitamin D and bone status, and magnetic resonance imaging (MRI) in adult PKU patients according to serum phenylalanine level. Oxidative stress increased markedly at serum phenylalanine of 700-800 μmol/L. Serum phenylalanine higher than 700-850 μmol/L correlated with the disturbance of nitric oxide regulatory system. Adult PKU patients had poor vitamin D status and exhibited predominance of bone resorption over bone formation. In the brain, the levels of 24S-hydroxycholesterol, a marker of brain cholesterol elimination, were low at serum phenylalanine levels exceeding 650 μmol/L. MRI studies showed high signal intensity in deep white matter on T2-weighted and FLAIR images of PKU patients with serum phenylalanine greater than 500 μmol/L, with decreased apparent diffusion coefficients. Changes in most parameters covering the entire body organs in adult PKU were almost acceptable below 700-800 μmol/L of phenylalanine level. However, the optimal serum phenylalanine level should be 500 μmol/L or less in later life for the brain to be safe.