The Association of Small Dense Low-Density Lipoprotein Cholesterol and Coronary Heart Disease in Subjects at High Cardiovascular Risk

Association between Hemoglobin A1c and Renal Arteriolar Sclerosis in Subjects Presenting without any Apparent Kidney Dysfunction

AIMS

Diabetic kidney disease is a major vascular complication in patients with diabetes mellitus (DM). However, the association between the hemoglobin (Hb)A1c levels, notably the prediabetic levels, and renal pathological changes remains unclear. We investigated the association between the HbA1c levels and renal arteriolar lesions in subjects without any apparent kidney dysfunction using a living kidney donor cohort.

METHODS

Between January 2006 and May 2016, 393 living kidney donors underwent a "zero-time" biopsy at Kyushu University Hospital. The patients were divided into four groups (HbA1c levels ＜5.6%, 5.6%-5.7%, 5.8%-6.4%, and ≥ 6.5%, or diagnosed with DM [DM group]). Renal arteriolar hyalinization and wall thickening were assessed using semi-quantitative grading. We then investigated the association between the HbA1c levels and renal pathological changes.

RESULTS

158 (40.2%) patients had arteriolar hyalinization and 148 (37.6%) showed wall thickening. A significant correlation was observed between the HbA1c levels and wall thickening (p for trend ＜0.001). An elevated HbA1c level was significantly associated with wall thickening according to a multivariable logistic analysis in subjects with HbA1c levels of 5.6%-5.7% and 5.8%-6.4%, and the DM group, compared with those with HbA1c levels of ＜5.6% (odds ratio [OR], 1.91; 95% confidence interval [CI]: [1.03-3.54] for 5.6%-5.7%, OR, 1.96; 95% CI: [1.09-3.53] for 5.8%-6.4%, and OR, 2.86; 95% CI: [0.91-9.01] for the DM group), whereas arteriolar hyalinization did not increase within the nondiabetic HbA1c levels.

CONCLUSIONS

Elevated high-normal HbA1c levels are considered to be independent risk factors for arteriolar wall thickening. Subclinical renal arteriolar sclerosis may develop in patients with prediabetic HbA1c levels.

Role of Small Dense Low-density Lipoprotein Cholesterol in Cardiovascular Events in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus Receiving Statin Treatment

AIM

There is little information on the relationships of serum small dense low-density lipoprotein cholesterol (sdLDL-C) levels and serum triglyceride (TG) levels with cardiovascular events in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (DM) who are receiving statins. The aim of this study was to evaluate the relationships of serum TG levels and sdLDL-C levels as residual risks for cardiovascular events in patients with CAD and type 2 DM who were being treated with statins.

METHODS

The subjects were divided into four groups based on TG levels and sdLDL-C levels: sdLDL-C of ＜40.0 mg/dL and TG of ＜150 mg/dL, sdLDL-C of ≥ 40.0 mg/dL and TG of ＜150 mg/dL, sdLDL-C of ＜40.0 mg/dL and TG of ≥ 150 mg/dL, and sdLDL-C of ≥ 40.0 mg/dL and TG of ≥ 150 mg/dL. During a median follow-up period of 1419 days, cardiovascular events occurred in 34 patients.

RESULTS

The incidences of cardiovascular events were significantly higher in patients with sdLDL-C of ≥ 40.0 mg/dL and TG of ＜150 mg/dL and in patients with sdLDL-C of ≥ 40.0 mg/dL and TG of ≥ 150 mg/dL, but not in patients with sdLDL-C of ＜40.0 mg/dL and TG of ≥ 150 mg/dL, than in patients with sdLDL-C of ＜40.0 mg/dL and TG of ＜150 mg/dL.

CONCLUSIONS

Under the condition of treatment with statins, patients with CAD and type 2 DM who had sdLDL-C levels of ≥ 40.0 mg/dL had a high risk for cardiovascular events even though serum TG levels were controlled at ＜150 mg/dL.

Calculated Small Dense Low-Density Lipoprotein Cholesterol Level is A Predominant Predictor for New Onset of Ischemic Heart Disease

AIM

A high level of directly measured small dense low-density lipoprotein cholesterol (sdLDL-C) is a strong risk factor for ischemic heart disease (IHD). However, it remains unclear whether estimated sdLDL-C level is a predictor for IHD. We investigated the associations of new onset of IHD with levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides (TG), LDL-C and calculated sdLDL-C by Sampson's equation.

METHODS

After exclusion of subjects with IHD or those with TG ≥ 800 mg/dL, a total of 18,176 subjects (men/women: 11,712/6,464, mean age: 46 years) were recruited among 28,990 Japanese individuals who received annual health checkups.

RESULTS

During the 10-year follow-up period, 456 men (3.9%) and 121 women (1.9%) newly developed IHD. Multivariable Cox proportional hazard analyses after adjustment of age, sex, obesity, smoking habit, family history of IHD, estimated glomerular filtration rate, hypertension and diabetes mellitus at baseline showed that the hazard ratio (HR) (1.38 [95% confidence interval: 1.03-1.85]) for new onset of IHD in subjects with the 4th quartile (Q4) of sdLDL-C (≥ 42 mg/dL) was significantly higher than that in subjects with the 1st quartile (Q1) (≤ 24 mg/dL) as the reference, though the adjusted HRs in subjects with Q2-Q4 of TC, HDL-C, non-HDL-C, LDL-C and TG were comparable with those in subjects with Q1 of the respective lipid fractions. The adjusted HR with a restricted cubic spline increased with a higher level of calculated sdLDL-C as a continuous value at baseline.

CONCLUSIONS

sdLDL-C level calculated by Sampson's equation is a predominant predictor for the development of IHD in a general Japanese population.

Low-density lipoprotein cholesterol and risk of hepatocellular carcinoma: a Mendelian randomization and mediation analysis

BACKGROUND

A previous study demonstrated that low-density lipoprotein cholesterol (LDL-C) is associated with hepatocellular carcinoma (HCC); however, the causality between them has not been proven due to conflicting research results and the interference of confounders. This study utilized Mendelian randomization (MR) to investigate the causal relationship between LDL-C and HCC and identify the mediating factors.

METHODS

LDL-C, HCC, and coronary artery disease (CAD) genome-wide association study (GWAS) data were obtained from a public database. To investigate causality, inverse variance weighting (IVW) was the main analysis approach. MR‒Egger, simple mode, weighted median (WM), and weighted mode were employed as supplementary analytic methods. In addition, horizontal pleiotropy and heterogeneity were tested. To evaluate the stability of the MR results, a "leave-one-out" approach was used. Multivariate MR (MVMR) was utilized to correct the confounders that might affect causality, and mediation analysis was used to investigate the potential mediating effects. Finally, we used HCC risk to infer the reverse causality with LDL-C level.

RESULTS

Random effects IVW results were (LDL-C-HCC: odds ratio (OR) = 0.703, 95% confidence interval (CI) = [0.508, 0.973], P = 0.034; CAD-HCC: OR = 0.722, 95% CI = [0.645, 0.808], P = 1.50 × 10^-8; LDL-C-CAD: OR = 2.103, 95% CI = [1.862, 2.376], P = 5.65 × 10^-33), demonstrating a causal link between LDL-C levels and a lower risk of HCC. Through MVMR, after mutual correction, the causal effect of LDL-C and CAD on HCC remained significant (P < 0.05). Through mediation analysis, it was proven that CAD mediated the causative connection between LDL-C and HCC, and the proportion of mediating effect on HCC was 58.52%. Reverse MR showed that HCC could affect LDL-C levels with a negative correlation (OR_IVW = 0.979, 95% CI = [0.961, 0.997], P = 0.025).

CONCLUSION

This MR study confirmed the causal effect between LDL-C levels and HCC risk, with CAD playing a mediating role. It may provide a new view on HCC occurrence and development mechanisms, as well as new metabolic intervention targets for treatment.

Small Dense LDL Level and LDL/HDL Distribution in Acute Coronary Syndrome Patients

This study aimed to determine the size and distribution of LDL and HDL particles in North African acute coronary syndrome (ACS) patients and to compare the level of small dense LDL (sdLDL) to other markers used in cardiovascular risk prediction.

METHODS

A total of 205 ACS patients and 100 healthy control subjects were enrolled. LDL particle size and LDL and HDL subclass distributions were measured using Quantimetric Lipoprint^® linear polyacrylamide gel electrophoresis. Lipid ratios (total cholesterol, LDL cholesterol, non-HDL cholesterol, and HDL cholesterol) were determined to calculate the atherogenic index of plasma (AIP), the atherogenic coefficient (AC), Castelli's Risk-I (CR-I), and Castelli's Risk-II (CR-II). Receiver operating characteristic (ROC) curve analyses and area under the curve (AUC) were used to assess the predictive value of sdLDL as a marker for cardiovascular disease.

RESULTS

The ACS patients, compared to the healthy control subjects, displayed an alteration of LDL particle distribution, with a significant increase in sdLDL serum concentrations (0.303 ± 0.478 mmol/L vs. 0.0225 ± 0.043 mmol/L, respectively, p < 0.001). The sdLDL levels had a high discrimination accuracy [AUC = 0.847 ± 0.0353 (95% CI 0.778 to 0.916, p < 0.0001)]. The best predictive cutoff value of ACS determined with the maximum Youden index (J) [(sensitivity + specificity) - 1 = 0.60] was 0.038 mmol/L. A Spearman correlation analysis showed that sdLDL levels were moderately but significantly and positively correlated with AC and CR-I (r = 0.37, p < 0.001) and weakly but significantly correlated with PAI and CR-II; r = 0.32 (p < 0.001) and r = 0.30 (p < 0.008), respectively. The subclass distribution of HDL particles from ACS patients was also altered, with a decrease in large HDL particles and an increase in small HDL particles compared to HDL from healthy control subjects.

CONCLUSION

Due to their high atherogenicity, sdLDL levels could be used as a valuable marker for the prediction cardiovascular events.

Small dense low-density lipoprotein cholesterol compared to other lipoprotein biomarkers for predicting coronary heart disease among individuals with normal fasting glucose: The Multi-Ethnic Study of Atherosclerosis

Objective

This study compared small dense low-density lipoprotein cholesterol (sdLDL-C) with apolipoprotein B (apo B), and low-density lipoprotein particles (LDL-P) in predicting CHD risk in generally healthy adults with normal fasting glucose (NFG).

Methods

This study was conducted among participants with NFG in the Multi-Ethnic Study of Atherosclerosis (MESA) prospective cohort with measurements of sdLDL-C, LDL-P, and apo B available at baseline (2000-2002) and follow-up CHD data (through 2015) (N = 3,258). Biomarkers were evaluated as quartiles, and in categories using clinically and 75th percentile-defined cut-points. Discordance/concordance of sdLDL-C relative to other biomarkers was calculated using 75th percentile cut-points and linear regression residuals. Associations between individual biomarkers, sdLDL-C discordance and CHD incidence were evaluated using Cox proportional hazards regression.

Results

There were 241 incident CHD events in this population through 2015. Higher sdLDL-C, apo B, LDL-P were similarly associated with increased CHD in individuals with NFG. Discordance of sdLDL-C with apo B or LDL-P by 75th percentiles was not significantly associated with CHD. Residuals discordantly higher/lower sdLDL-C relative to apo B (discordant high HR=1.26, 95% CI: 0.89, 1.78; discordant low HR=0.94, 95% CI: 0.68, 1.29) and LDL-P (discordant high HR=1.25, 95% CI: 0.88, 1.75; discordant low HR=0.84, 95% CI:0.60, 1.16), compared to those with concordant measures, had non-statistically significant higher/lower risk of CHD.

Conclusions

Results suggest sdLDL-C, apo B and LDL-P are generally comparable for predicting CHD events in normoglycemic individuals. Larger studies are needed to confirm findings and to investigate whether measurement of sdLDL-C may be beneficial to evaluate as an additional risk-enhancing factor.

Reference interval for serum concentration of small dense low-density lipoprotein cholesterol in the healthy Japanese population

BACKGROUND

Small dense low-density lipoprotein a smaller and denser subfraction among whole low density lipoprotein particles is known to be highly atherogenic. The reference interval (RI) is not strictly defined for serum concentration of sdLDL-cholesterol (sdLDL-C) in Japan. The purpose of this study is to set the reference interval for sdLDL-C in healthy subjects.

METHODS

The population of this cross-sectional study was consisted of 40,862 individuals who had annual health checkups, and healthy subjects were extracted based on exclusion criteria such as medical history, social history, and blood sampling test results. Their serum sdLDL-C values were statistically analyzed and the RIs were set in men, premenopausal women, and postmenopausal women separately.

RESULTS

The mean values of serum sdLDL-C in healthy subjects were 23.9 mg/dL in men, 20.0 mg/dL in premenopausal women and 23.7 mg/dL in postmenopausal women, and the RIs were 12.6-45.3 mg/dL in men, 11.4-35.1 mg/dL in premenopausal women and 14.6-38.6 mg/dL in postmenopausal women. Serum sdLDL-C values were significantly higher in men than in women. Besides, sdLDL-C values were significantly higher in postmenopausal women than in premenopausal women. In both genders, sdLDL-C values tended to increase with age.

CONCLUSION

These results suggest that the RIs for sdLDL-C are recommended as follows: 13-45 mg/dL in men, 11-35 mg/dL in premenopausal women, and 15-39 mg/dL in postmenopausal women, respectively. Aside from these RIs, it is also necessary to define clinical cutoff values graded according to individual risk levels for atherosclerotic cardiovascular diseases.

Small, Dense Low-Density Lipoprotein-Cholesterol and Atherosclerosis: Relationship and Therapeutic Strategies

Low-density lipoprotein cholesterol (LDL-C) plays an important role in the formation, incidence, and development of atherosclerosis (AS). Low-density lipoproteins can be divided into two categories: large and light LDL-C and small, dense low-density lipoprotein cholesterol (sdLDL-C). In recent years, an increasing number of studies have shown that sdLDL-C has a strong ability to cause AS because of its unique characteristics, such as having small-sized particles and low density. Therefore, this has become the focus of further research. However, the specific mechanisms regarding the involvement of sdLDL-C in AS have not been fully explained. This paper reviews the possible mechanisms of sdLDL-C in AS by reviewing relevant literature in recent years. It was found that sdLDL-C can increase the atherogenic effect by regulating the activity of gene networks, monocytes, and enzymes. This article also reviews the research progress on the effects of sdLDL-C on endothelial function, lipid metabolism, and inflammation; it also discusses its intervention effect. Diet, exercise, and other non-drug interventions can improve sdLDL-C levels. Further, drug interventions such as statins, fibrates, ezetimibe, and niacin have also been found to improve sdLDL-C levels.

Kyushu and Okinawa Population Study (KOPS): a large prospective cohort study in Japan

PURPOSE

The Kyushu and Okinawa Population Study (KOPS) was established to investigate gene-environmental interactions in non-communicable diseases in Japan. Besides collecting blood samples and anthropometric measurements, we also obtained medical histories, psychological status and lifestyle habits, including physical activities and dietary patterns.

PARTICIPANTS

KOPS is a community-based prospective cohort study and consists of participants from four southwestern areas in Japan. Baseline surveys were conducted between 2004 and 2007 (wave 1), and 2009 and 2012 (wave 2) at the sites of municipality-based health check-ups. A total of 17 077 participants were included, comprising 10 697 participants of wave 1 and 6380 participants of wave 2; the median age in both groups was 61 years. Among them, 3006 individuals participated in both wave 1 and wave 2 surveys.

FINDINGS TO DATE

We have focused on either risk or confounding factors for non-communicable diseases. We have assessed the clinical utility of the newly developed biomarkers for impaired glucose tolerance, such as urinary myo-inositol and glycated albumin, and atherosclerosis, such as small dense low-density lipoprotein cholesterol. We have conducted an international collaborative study with Framingham Offspring Study to investigate ethnic differences in impaired glucose tolerance and cardiovascular diseases. We have found that insulin resistance and deficiency might account for the ethnic differences in impaired glucose tolerance and cardiovascular disease risks. As gene-environmental interaction analyses, we found a synergic effect of interleukin 28B single nucleotide polymorphisms (SNPs) and gender on the spontaneous elimination of hepatitis C, and a beneficial interaction of SNPs of high-density lipoprotein cholesterol and gender on the impact of physical activity. In addition, we reported eight novel loci contributing to the development and severity of coronary artery disease from a large genome-wide association study.

FUTURE PLANS

We plan to investigate further the clinical utility of the newly developed biomarkers and the gene-environmental interactions using prospective data.

Association of serum 25-Hydroxy Vitamin D level with lipid, lipoprotein, and apolipoprotein level

Introduction 25-Hydroxy vitamin D (Vit D3) deficiency was found to be associated with vascular dysfunction, arterial stiffening, extent of coronary artery disease and cardiovascular mortality. Previous studies showed positive correlation between serum Vit D3 and HDL-C and negative correlation between Vit D3 and LDL-C. The aim of this study is to investigate more details about the possible association of serum Vit D3 level with lipid, lipoprotein and apolipoprotein level. Methods Totally 101 patients were included in this study and Vit D3, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), High-density lipoprotein cholesterol (HDL-C), total triglyceride (TG), non-high-density lipoprotein cholesterol (Non-HDL-C), low-density lipoprotein particle (LDL-P), small dense low-density lipoprotein particle (sLDL-P), small dense low-density lipoprotein cholesterol (sdLDL-C), High-density lipoprotein cholesterol particles (HDL-P), High-density lipoprotein 2-cholesterol (HDL2-C), Apolipoprotein B(ApoB), Apolipoprotein A1 (Apo A1) and Apolipoprotein B/Apolipoprotein A1 ratio (ApoB/A ratio) were tested. Results Our results show that patients with Vit D3 deficiency (Vit D3 < 30 ng/ml) have significantly higher level of LDL-C, TG, Non-HDL-C, LDL-P, sLDL-P, sdLDL-C, ApoB and ApoB/A ratio compare with patients have normal Vit D3 level (Vit D3 > 30 ng/ml). Patients with normal Vit D3 level have significantly higher level of HDL-C and HDL2-C. Correlation study shows that Vit D3 level is negative correlated with TC, LDL-C, TG, Non-HDL-C, LDL-P, sLDL-P, sdLDL-C, ApoB and ApoB/A ratio and positive correlated with HDL2-C level. Conclusion Our results show that Vit D3 deficiency links to an increased risk for dyslipidemia and that may be the reason that patients with vitamin D deficiency tend to have higher risk of coronary artery disease.

MAFLD better predicts the progression of atherosclerotic cardiovascular risk than NAFLD: Generalized estimating equation approach

AIM

Metabolic associated fatty liver disease (MAFLD) partly overlaps with non-alcoholic fatty liver disease (NAFLD). Thus, using a generalized estimating equation (GEE) approach, we aimed to investigate the difference in worsening of atherosclerotic cardiovascular disease (ASCVD) risk between patients with MAFLD and NAFLD. We also investigated factors related to the difference between the two groups.

METHODS

We enrolled 2306 subjects with fatty liver (MAFLD 80.7%, NAFLD 63.4%). Subjects with MAFLD/NAFLD were sub-classified into three groups: NAFLD with no metabolic dysfunction (non-Met NAFLD), overlapping, and MAFLD with moderate alcohol consumption (mod-Alc MAFLD). ASCVD risk was estimated by non-invasive tests, including the Suita score. An event was defined as worsening of these scores from the low-risk to the high-risk group. Independent factors for the event were analyzed by Cox regression analysis with the GEE.

RESULTS

In Cox regression analysis, MAFLD (HR 1.08, 95% CI 1.02-1.15, p = 0.014) and alcohol consumption (20-39 g/day; HR 1.73, 95% CI 1.26-2.36, p = 0.001) were independently associated with worsening of the Suita score. In a subanalysis, the incidence of the event was significantly lower in non-Met NAFLD than in the overlapping group (HR 0.70, 95% CI 0.50-0.98, p = 0.042). However, no significant difference was observed in the incidence between the overlapping and mod-Alc MAFLD group (HR 1.19, 95% CI 0.89-1.58, p = 0.235).

CONCLUSIONS

The GEE approach demonstrates that MAFLD better identifies patients with worsening of ASCVD risk than NAFLD. Moreover, the superiority of MAFLD over NAFLD was due to the presence of metabolic dysfunction rather than moderate alcohol consumption.

Small Dense Low-Density Lipoprotein Cholesterol: A Residual Risk for Rapid Progression of Non-Culprit Coronary Lesion in Patients with Acute Coronary Syndrome

AIM

This study investigated whether the small dense low-density lipoprotein cholesterol (sd-LDL-c) level is associated with the rapid progression (RP) of non-culprit coronary artery lesions and cardiovascular events (CE) after acute coronary syndrome (ACS).

METHODS

In 142 consecutive patients with ACS who underwent primary percutaneous coronary intervention for the culprit lesion, the sd-LDL-c level was measured using a direct homogeneous assay on admission for ACS and at the 10-month follow-up coronary angiography. RP was defined as a progression of any pre-existing coronary stenosis and/or stenosis development in the initially normal coronary artery. CEs were defined as cardiac death, myocardial infarction, stroke, or coronary revascularization.

RESULTS

Patients were divided into two groups based on the presence (n=29) or absence (n=113) of RP after 10 months. The LDL-c and sd-LDL-c levels at baseline were equivalent in both the groups. However, the sd-LDL-c, triglyceride, remnant lipoprotein cholesterol (RL-c), and apoC3 levels at follow-up were significantly higher in the RP group than in the non-RP group. The optimal threshold values of sd-LDL-c, triglyceride, RL-c, and apoC3 for predicting RP according to receiver operating characteristics analysis were 20.9, 113, 5.5, and 9.7 mg/dL, respectively. Only the sd-LDL-c level (≥ 20.9 mg/dL) was significantly associated with incident CEs at 31±17 months (log-rank: 4.123, p=0.043).

CONCLUSIONS

The sd-LDL-c level on treatment was significantly associated with RP of non-culprit lesions, resulting in CEs in ACS patients. On-treatment sd-LDL-c is a residual risk and aggressive reduction of sd-LDL-c might be needed to prevent CEs.