Smaller Mean LDL Particle Size and Higher Proportion of Small Dense LDL in Korean Type 2 Diabetic Patients

Nrf2 Signaling Pathway as a Key to Treatment for Diabetic Dyslipidemia and Atherosclerosis

Diabetes mellitus (DM) is a chronic endocrine disorder that affects more than 20 million people in the United States. DM-related complications affect multiple organ systems and are a significant cause of morbidity and mortality among people with DM. Of the numerous acute and chronic complications, atherosclerosis due to diabetic dyslipidemia is a condition that can lead to many life-threatening diseases, such as stroke, coronary artery disease, and myocardial infarction. The nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway is an emerging antioxidative pathway and a promising target for the treatment of DM and its complications. This review aims to explore the Nrf2 pathway's role in combating diabetic dyslipidemia. We will explore risk factors for diabetic dyslipidemia at a cellular level and aim to elucidate how the Nrf2 pathway becomes a potential therapeutic target for DM-related atherosclerosis.

Evaluation of measured and calculated small dense low-density lipoprotein in capillary blood and association with the metabolic syndrome

BACKGROUND AND AIMS

Small-dense-low-density-lipoprotein cholesterol (sdLDL-C) is proatherogenic and not commonly measured. The aims were to evaluate capillary blood and its stability for sdLDL-C measurement and measure sdLDL-C in patients with metabolic syndrome (MS).

METHODS

182 patients were studied (49 with MS). sdLDL-C was measured by electrophoresis (LipoPrint®), direct measurement (Roche Diagnostics) and Sampson equation. Intima-media thickness (IMT) and presence of atheroma was evaluated. sdLDL-C was compared in paired venous and capillary blood according to CLSI-EP09c (n = 40). sdLDL-C stability was studied after 24 h at room temperature (RT).

RESULTS

sdLDL-C in capillary blood and venous blood showed agreement with the direct measurement (bias: 4.17 mg/dL, LOA 95 %:-5.66; 13.99) and estimation (bias:8.12 mg/dL, LOA 95 %:-8.59; 24.82). sdLDL-C is stable in capillary blood for 24 h at RT. The electrophoretic method yielded lower (p < 0.05) sdLDL-C than the equation or direct measurement. Patients with MS had (p < 0.05) higher sdLDL-C (%) than patients without MS. Patients with atheroma plaques had higher sdLDL-C (p < 0.05). Estimated sdLDL-C correlated with IMT (r = 0.259, p < 0.001).

CONCLUSIONS

Capillary blood is an alternative to venous blood for sdLDL-C measurement and is stable for 24 h after collection. Estimated and directly measured sdLDL-C associate with the MS being accessible tools for cardiovascular risk assessment.

The association of apolipoprotein in the risk of ST-elevation myocardial infarction in patients with documented coronary artery disease

Introduction

Cardiovascular disease (CVD) is the number one cause of death worldwide, in this case, acute coronary syndrome (ACS) or acute myocardial infarction (AMI) that developed from coronary artery disease (CAD). Several risk factors contribute to AMI. Non-modifiable risk factors are age, sex, race, and family history. Modifiable risk factors include dyslipidemia, hypertension, smoking, diabetes mellitus, as well as recent factors that are considered more specific such as homocysteine, lipoprotein a [Lp(a)], high sensitivity C- reactive protein (hs-CRP), and apolipoprotein. This study aimed to determine the role of apolipoprotein as a risk factor for STEMI.

Methods

This study combines three epidemiological designs: a descriptive and cross-sectional correlative study with 62 STEMI patients at the National Cardiovascular Center Harapan Kita and a comparative study of 62 STEMI patients and 20 non-ACS CAD patients at the Universitas Indonesia Hospital.

Results and conclusion

The descriptive study showed the level of apoB 80.71 ± 28.3, apoA1 104.93 ± 27.8, apoB/apoA1 ratio 0.78 ± 0.22, and Lp(a) 6.85 (1.0-48.1). ApoB moderately correlates with LDLc (p < 0.001; r = 0.571). ApoA1 weakly correlates with HDLc (p = 0.005; r = 0.379). In comparative study, there were significant differences between the STEMI and non-ACS CAD groups on apoA1 (104.93 ± 27.8 vs. 137.48 ± 26.46), apoB/apoA1 ratio (0.78 ± 0.22 vs. 0.59 ± 0.15), and hs-CRP (2.88 [0.4-215] vs. 0.73 [0.15-8.9]). Multivariate analysis showed that the most significant risk factors for STEMI in this study were hypertension for modifiable factors and apoA1 for apolipoprotein. The apoA1 and apoB/apoA1 ratio examination can be suggested for people who have experienced plaque formation and are at risk for myocardial infarction.

Association between measured or calculated small dense low-density lipoprotein cholesterol and oxidized low-density lipoprotein in subjects with or without type 2 diabetes mellitus

BACKGROUND

Small dense low-density lipoprotein (sdLDL) possesses atherogenic potential and is predicted to be susceptible to atherogenic modifications, which further increases its atherogenicity. However, studies on the association between measured or estimated sdLDL cholesterol (sdLDL-C) levels and atherogenic modification in diverse population groups are lacking.

METHODS

Surplus serum samples were collected from male subjects with type 2 diabetes mellitus (DM) under treatment (n = 300) and without DM (non-DM; n = 150). sdLDL and oxidized LDL (oxLDL) levels were measured using the Lipoprint LDL subfractions kit (Quantimetrix Corporation) and the Mercodia oxidized LDL competitive enzyme-linked immunosorbent assay kit (Mercodia), respectively. The estimated sdLDL-Cs were calculated from two relevant equations. The effects of sdLDL-C on oxLDL were assessed using multiple linear regression (MLR) models.

RESULTS

The mean (±SD) of measured sdLDL-C and oxLDL concentrations were 11.8 ± 10.0 mg/dl and 53.4 ± 14.2 U/L in the non-DM group and 0.20 ± 0.81 mg/dl and 46.0 ± 15.3 U/L in the DM group, respectively. The effects of measured sdLDL-Cs were significant (p = 0.031), whereas those of estimated sdLDL-Cs were not (p = 0.060, p = 0.116) in the non-DM group in the MLR models. The effects of sdLDL-Cs in the DM group were not significant.

CONCLUSION

In the general population, high level of sdLDL-C appeared to be associated with high level of oxLDL. The equation for estimating sdLDL-C developed from a general population should be applied with caution to a special population, such as patients with DM on treatment.

Atherogenic Index of Plasma and Its Association with Risk Factors of Coronary Artery Disease and Nutrient Intake in Korean Adult Men: The 2013-2014 KNHANES

Coronary artery disease (CAD) has been linked to one of the highest death rates globally. The atherogenic index of plasma (AIP) may be an important predictor of atherosclerosis and cardiovascular disease, superior to the standard atherosclerotic lipid profile. This study investigated the relationship between AIP and obesity indices, blood glucose, lipid profile, and nutrient intake status in Korean adult men. The study included 1292 males aged ≥19 years old who participated in the Korea National Health and Nutrition Examination Survey, 2013-2014. Participants were divided into four groups according to AIP quartiles, calculated as log (triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C)). Body mass index, waist circumference, fasting blood glucose, hemoglobin A1c, total cholesterol, TG, and low-density lipoprotein cholesterol levels increased as AIP levels increased, whereas HDL-C level declined. As the level of AIP increased, intake of saturated fatty acid, calcium, phosphorus, riboflavin, milk, and dairy product decreased significantly, and the contribution rate of milk and dairy products to fat intake decreased. AIP was linked to obesity indices, blood glucose, and blood lipid profile in Korean men, suggesting that it could predict CAD.

The Atherogenic Index of Plasma: A Powerful and Reliable Predictor for Coronary Artery Disease in Patients With Type 2 Diabetes

We evaluated the predictive power of the atherogenic index of plasma (AIP) for coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM). A total of 3278 patients who underwent coronary angiography were consecutively enrolled, including 2052 patients with CAD and 1226 patients with T2DM but without CAD. Patients in the CAD group had higher levels of triglyceride (TG), total cholesterol, low-density lipoprotein cholesterol, AIP and a lower level of high-density lipoprotein cholesterol (HDL-C). In correlation analyses, AIP correlated positively with body mass index, log (homeostasis model assessment of insulin resistance), TG, remnant lipoprotein cholesterol, non-HDL-C, but negatively with age and HDL-C. Multivariate logistic regression analyses demonstrated that AIP was an independent risk factor for CAD in diabetic patients and was validated by multiple models. Furthermore, the ORs for CAD risk were raised with increasing AIP quartiles; ORs of AIP quartiles Q2-Q4 compared with Q1 were 1.56, 1.70, and 2.22, respectively (Ps < .001), which suggested AIP was the lipid parameter that most strongly associated with incident CAD. In conclusion, AIP is a powerful and reliable biomarker for predicting CAD risk beyond individual lipid profiles in patients with T2DM.

Direct bilirubin is associated with low-density lipoprotein subfractions and particle size in overweight and centrally obese women

BACKGROUND AND AIMS

Bilirubin has antioxidant and anti-inflammatory properties; serum bilirubin levels have been known to be inversely associated with cardiovascular disease. However, the effects of different bilirubin subtypes on cardiometabolic traits are unknown. In this study, we aimed to determine whether direct bilirubin is more strongly correlated with small, dense low-density lipoprotein (sdLDL) compared to other bilirubin subtypes. We also investigated which LDL subfractions exhibited the highest correlation with direct bilirubin.

METHODS AND RESULTS

A total of 288 overweight and centrally obese women were included in this study. The Pearson correlation and Steiger's Z test were used to compare the correlation coefficients between bilirubin subtypes and lipoproteins. Multiple linear regression analyses were used to evaluate the independent association between direct bilirubin and mean LDL particle size. Only direct bilirubin levels were significantly associated with the sdLDL subfraction and mean LDL particle size. Mean LDL particle size exhibited a significantly stronger correlation with direct bilirubin than sdLDL, percent sdLDL, and the sdLDL:large LDL ratio. Regression analysis showed that direct bilirubin was significantly associated with mean LDL particle size, according to both the stepwise method (β = 11.445, P value = 0.002) and the enter method (β = 11.655, P value = 0.002).

CONCLUSIONS

Direct bilirubin is more strongly correlated with the sdLDL subfraction compared with total and indirect bilirubin, and is independently associated with mean LDL particle size in overweight and centrally obese women.

Correlation between Cholesterol, Triglycerides, Calculated, and Measured Lipoproteins: Whether Calculated Small Density Lipoprotein Fraction Predicts Cardiovascular Risks

Background

Recent literature in lipidology has identified LDL-fractions to be more atherogenic. In this regard, small density LDL-cholesterol (sdLDLc) has been considered to possess more atherogenicity than other LDL-fractions like large buoyant LDL-cholesterol (lbLDLc). Recently, Srisawasdi et al. have developed a method for calculating sdLDLc and lbLDLc based upon a regression equation. Using that in developing world may provide us with a valuable tool for ASCVD risk prediction.

Objective

(1) To correlate directly measured and calculated lipid indices with insulin resistance, UACR, glycated hemoglobin, anthropometric indices, and blood pressure. (2) To evaluate these lipid parameters in subjects with or without metabolic syndrome, nephropathy, and hypertension and among various groups based upon glycated hemoglobin results.

Design

Cross-sectional study. Place and Duration of Study. From Jan 2016 to 15 April 2017.

Subjects and Methods

Finally enrolled subjects (male: 110, female: 122) were evaluated for differences in various lipid parameters, including measured LDL-cholesterol (mLDLc), HDLc and calculated LDL-cholesterol (cLDLc), non-HDLc, sdLDLC, lbLDLC, and their ratio among subjects with or without metabolic syndrome, nephropathy, glycation index, anthropometric indices, and hypertension.

Results

Significant but weak correlation was mainly observed between anthropometric indices, insulin resistance, blood pressure, and nephropathy for non-HDLc, sdLDLc, and sdLDLc/lbLDLc. Generally lipid indices were higher among subjects with metabolic syndrome [{sdLDLc: 0.92 + 0.33 versus 0.70 + 0.29 (p < 0.001)}, {sdLDLc/lbLDLc: 0.55 + 0.51 versus 0.40 + 0.38 (p = 0.010)}, {non-HDLc: 3,63 + 0.60 versus 3.36 + 0.65 (p = 0.002)}]. The fact that the sdLDLc levels provided were insignificant in Kruskall Wallis Test indicated a sharp increase in subjects with HbA1c > 7.0%. Subjects having nephropathy (UACR > 2.4 mg/g) had higher concentration of non-HDLc levels in comparison to sdLDLc [{non-HDLc: 3.68 + 0.59 versus 3.36 + 0.43} (p = 0.007), {sdLDLc: 0.83 + 0.27 versus 0.75 + 0.35 (p = NS)}].

Conclusion

Lipid markers including cLDLc and mLDLc are less associated with traditional ASCVD markers than non-HDLc, sdLDLc, and sdLDLc/lbLDLc in predicting metabolic syndrome, nephropathy, glycation status, and hypertension.

Prepregnancy Adverse Lipid Profile and Subsequent Risk of Gestational Diabetes

CONTEXT

Lower low-density lipoprotein (LDL) peak diameter and a predominance of small, dense LDL are associated with type 2 diabetes, but it is unclear whether they are a risk factor for gestational diabetes mellitus (GDM).

OBJECTIVE

To evaluate whether prepregnancy lipid profile predicts the development of GDM during pregnancy.

DESIGN

A nested case-control study among women who participated in a multiphasic health exam, where blood was collected and stored between 1984 and 1996, and who then had a subsequent pregnancy between 1984 and 2009.

SETTING

Kaiser Permanente Northern California.

PARTICIPANTS

Cases were 254 women who developed GDM. Two controls were selected for each case and matched for year of blood draw, age at baseline, age at pregnancy, and number of intervening pregnancies.

MAIN OUTCOME MEASURES

Prepregnancy LDL peak diameter and prepregnancy lipid subfraction concentrations grouped according to size, and the odds of developing GDM.

RESULTS

Women in the lowest quartiles of LDL peak diameter and high-density lipoprotein had increased odds of GDM compared with women in the highest quartiles (odds ratio [95% CI], 2.60 [1.37-4.94] and 1.98 [1.01-3.86], respectively), in multivariable adjusted models. Being in the highest quartile of small and very small LDL subfractions also increased the odds of GDM (2.61 [1.35-5.03] and 2.44 [1.22-4.85], respectively).

CONCLUSIONS

Lower LDL peak diameter size and high-density lipoprotein levels and higher levels of small and very small LDL subfraction groups were present years before pregnancy in women who developed GDM. A prepregnancy atherogenic lipid profile may help identify women at risk of GDM to target for prevention.

Lipoprotein associated phospholipase A2 activity & its correlation with oxidized LDL & glycaemic status in early stages of type-2 diabetes mellitus

Background & objectives:

Lipoprotein associated phospholipase A₂ (Lp-PLA₂) is an important risk predictor of coronary artery disease (CAD). This study was aimed to evaluate Lp-PLA₂ activity and oxidized low density lipoprotein (oxLDL) in newly diagnosed patients of type 2 diabetes mellitus and to determine the correlation of Lp-PLA₂ activity with oxLDL and plasma glucose levels.

Methods:

Blood samples were collected in patients with newly diagnosed type 2 diabetes (n=40) before any treatment was started and healthy controls (n=40). These were processed for estimating plasma glucose: fasting and post prandial, ox LDL, and Lp-PLA2 activity. The parameters in the two groups were compared. Correlation between different parameters was calculated by Pearson correlation analysis in both groups.

Results:

Lp-PLA₂ activity (24.48 ± 4.91 vs 18.63 ± 5.29 nmol/min/ml, P<0.001) and oxLDL levels (52.46 ± 40.19 vs 33.26 ± 12.54 μmol/l, P<0.01) were significantly higher in patients as compared to those in controls. Lp-PLA₂ activity correlated positively with oxLDL in both controls (r=0.414, P<0.01), as well in patients (r=0.542, P<0.01). A positive correlation between Lp-PLA₂ activity and fasting plasma glucose levels was observed only in patients (r=0.348, P<0.05).

Interpretation & conclusions:

Result of this study implies that higher risk of CAD in patients with diabetes may be due to increase in Lp-PLA₂ activity during the early course of the disease. A positive correlation between enzyme activity and fasting plasma glucose indicates an association between hyperglycaemia and increased activity of Lp-PLA2. This may explain a higher occurrence of CAD in patients with diabetes. A positive correlation between oxLDL and Lp-PLA2 activity suggests that Lp-PLA2 activity may be affected by oxLDL also.

Meta-analysis of Atherogenic Index of Plasma and other lipid parameters in relation to risk of type 2 diabetes mellitus

AIMS

Diabetic dyslipidemia is one of important complication of type 2 diabetes mellitus (T2DM). Blood lipid parameters (e.g., triglyceride, TG; total cholesterol, TC; high-density lipoprotein cholesterol, HDL-C; low-density lipoprotein cholesterol, LDL-C; Atherogenic Index of Plasma defined as lg(TG/HDL-C), AIP), are important indexes in predicting risk of T2DM. This study performed comprehensive meta-analyses to evaluate the powers of these indexes, especially for AIP, on predicting risk of T2DM.

METHODS

We searched PubMed Database, China National Knowledge Infrastructure (CNKI) and Wanfang Database in February 2014 to identify eligible studies. Case-control studies that have mean baseline values of AIP were included. Random-effect models were used to pool the summary standardized mean difference (SMD) in meta-analysis.

RESULTS

Fifteen eligible studies, with a total sample size of 4010, were included in meta-analysis. All these studies reported positive associations between AIP and T2DM. Moreover, the SMD for the AIP is 1.78 (95% confidence interval (CI): 1.04-2.52), which is higher than for other parameters (TG: 0.93, 95% CI: 0.78-1.09; TC: 0.46, 95% CI: 0.21-0.71; HDL-C: -0.89, 95% CI: -1.18 to -0.60; and LDL-C: 0.44, 95% CI: 0.11-0.77). Meta-analysis of association between BMI and T2DM gave a SMD of 0.85 (95% CI: 0.38 to 1.32).

CONCLUSIONS

The results suggest that lipid parameters have ability to reflect the risk of T2DM, but AIP may be more closely associated with the risk of T2DM. The current results suggest AIP may be used as a simple, easily calculated parameter in assessing the risk of T2DM.

Higher levels of small dense low-density lipoprotein (LDL) are associated with cardiac autonomic neuropathy in patients with type 2 diabetes

AIM

To investigate the relationship between small dense LDL cholesterol and cardiac autonomic neuropathy among patients with Type 2 diabetes.

METHODS

A total of 175 patients who had not taken lipid-lowering agents previously were enrolled consecutively in this study. Small dense LDL cholesterol level was measured using polyacrylamide tube gel electrophoresis, which fractionates LDL cholesterol into seven components according to particle size and charge. We analysed the mean LDL cholesterol particle size and the proportion of small dense LDL cholesterol.

RESULTS

The mean (± sd) patient age was 56 (± 14) years, the mean (± sd) duration of diabetes was 10.3 (± 8.3) years, the mean (± sd) proportion of small dense LDL cholesterol was 21.3 (± 17.6)% and the mean (± sd) LDL cholesterol size was 26.33 (± 0.8) nm. Men with cardiac autonomic neuropathy had a longer duration of diabetes compared with those without cardiac autonomic neuropathy. Women with cardiac autonomic neuropathy had a larger waist circumference, higher plasma triglyceride levels, smaller mean (± sd) LDL cholesterol size [26.8 (± 4.3) nm vs 26.4 (± 6.9) nm; P < 0.01] and larger mean (± sd) proportion of small dense LDL cholesterol [10.1 (± 9.9)% vs 19.1 (± 16.8)%; P < 0.01] compared with those without cardiac autonomic neuropathy. After adjusting for other confounding risk factors, the triglyceride/ HDL cholesterol ratio (odds ratio = 1.698, 95% CI: 1.07-2.69; P = 0.025) and mean LDL cholesterol size (odds ratio = 0.873, 95% CI: 0.77-0.99; P = 0.038) remained as independent risk factors for cardiac autonomic neuropathy in women.

CONCLUSIONS

A more atherogenic lipid profile such as the triglyceride: HDL cholesterol ratio and a smaller mean LDL cholesterol particle size were related to the prevalence of cardiac autonomic neuropathy in women with Type 2 diabetes.

Sleep status and low-density lipoprotein particle size in a general Japanese female population: the MIMA study

OBJECTIVE

This study investigated the relationship between sleep adequacy and small dense low-density lipoprotein (sdLDL) in a Japanese population.

SUBJECTS AND METHODS

Clinical data, including atherosclerotic risk factors, in addition to the mean LDL particle size (LDL-PS) measured by gel electrophoresis, were evaluated in 136 community-dwelling female subjects (40-80 years old). The sleep status was self-reported and the subjects were divided into those who had inadequate sleep (≤ 6 or ≥ 9 h of sleep) and had adequate sleep (7-8 h).

RESULTS

The mean LDL-PS was significantly smaller in subjects with inadequate sleep [n = 68, 26.4 ± 0.4 (SD) nm] than in those with adequate sleep (n = 68, 26.6 ± 0.4 nm, p < 0.05). This difference remained significant and independent after adjusting for confounders (β = 0.15-0.19, p < 0.05).

CONCLUSION

Sleep adequacy was associated with the presence of sdLDL, while the influence of the sleep status on LDL-PS was minor in this population. Further research on the associations among sleep, sdLDL and cardiovascular disease prevention is warranted.