Small dense low-density lipoprotein cholesterol concentration and carotid atherosclerosis

Fabrication and Study of Dextran/Sulfonated Polysulfone Blend Membranes for Low-Density Lipoprotein Adsorption

The abnormal increase in low-density lipoprotein (LDL) in human blood is a main independent risk factor for the pathogenesis of atherosclerosis, whereas a reduced LDL level effectively lowers morbidity. It is important to develop LDL adsorption materials with high efficiency and selectivity, as well as to simplify their fabrication processes. In this paper, polysulfone (PSF), sulfonated polysulfone (SPSF), and sulfonated polysulfone/dextran (SPSF/GLU) membranes were successfully fabricated for LDL adsorption using a solution casting technique. Attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements confirmed the success of the preparation. The water contact angle decreased from 89.7 ± 3.4° (PSF) to 76.4 ± 3.2° (SPSF) and to 71.2 ± 1.9° (SPSF/GLU), respectively. BSA adsorption testing showed that the SPSF/GLU with surface enrichment of sulfonate groups and glycosyl groups possessed higher resistance to protein solution. The adsorption and desorption behaviors of the studied samples in single-protein or binary-protein solutions were systematically investigated by enzyme-linked immunosorbent assay (ELISA), The results showed that SPSF/GLU, which had excellent resistance to protein adsorption, possessed a similar adsorption capacity to that of PSF. SPSF membrane exhibited excellent selective affinity for LDL in single and binary protein solutions, suggesting potential applications in LDL removal.

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.

The predictive value of nontraditional lipid parameters for intracranial and extracranial atherosclerotic stenosis: a hospital-based observational study in China

BACKGROUND

Ischemic strokes are primarily caused by intracranial and extracranial atherosclerotic stenosis. Nontraditional lipid parameters broaden traditional lipid profiles, better reflect the metabolism and interaction between different lipid components, and optimize the predictive ability of lipid profiles for atherosclerotic diseases. This research was carried out to investigate the predictive value of nontraditional lipid parameters for intracranial or extracranial atherosclerotic stenosis.

METHODS

The investigation collected data from inpatients who underwent cervical vascular ultrasonography, carotid CTA, cerebral artery CTA or MRA, and brain MRI or CT from December 2014 to December 2021. The nontraditional lipid parameters were calculated by collecting traditional lipid parameters. To evaluate the predictive power of nontraditional lipid parameters, logistic regression and receiver operating characteristic curve (ROC) analyses were performed.

RESULTS

Based on the inclusion and exclusion criteria, 545 patients were included. According to the imaging results, inpatients were divided into two groups, including no intracranial or extracranial atherosclerotic stenosis (n = 250) and intracranial or extracranial atherosclerotic stenosis (AS, n = 295). Among them, AS was further divided into three subgroups: intracranial atherosclerotic stenosis (ICAS), extracranial atherosclerotic stenosis (ECAS) and combined intracranial and extracranial atherosclerotic stenosis (IECAS). Logistic regression analysis showed that nontraditional lipid parameters, including the atherogenic index of plasma (AIP), TG/HDL-C, remnant cholesterol (RC), nonhigh-density lipoprotein cholesterol (non-HDL-C), lipoprotein combine index (LCI), atherogenic coefficient (AC), Castelli's index-I (CRI-I) and Castelli's index-II (CRI-II), were significantly correlated with intracranial or extracranial atherosclerotic stenosis (P < 0.05). Compared with other nontraditional lipid parameters, regardless of adjusting for potential confounding factors, AIP had a greater OR value in ICAS (OR = 4.226, 95% CI: 1.681-10.625), ECAS (OR = 2.993, 95% CI: 1.119-8.003) and IECAS (OR = 4.502, 95% CI: 1.613-12.561). ROC curve analysis revealed that nontraditional lipid parameters had good predictive power for intracranial or extracranial atherosclerotic stenosis.

CONCLUSIONS

This Chinese hospital-based study demonstrates that nontraditional lipid parameters (AIP, LCI, RC, CRI-II, AC, CRI-I and non-HDL-C) are effective predictors of intracranial and extracranial atherosclerotic stenosis, of which AIP may be a significant risk factor for predicting atherosclerotic arterial stenosis in the intracranial or extracranial regions.

Associations of Lipids and Lipid-Lowering Drugs with Risk of Vascular Dementia: A Mendelian Randomization Study

Accumulating observational studies suggested that hypercholesterolemia is associated with vascular dementia (VaD); however, the causality between them remains unclear. Hence, the aim of this study is to infer causal associations of circulating lipid-related traits [including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), apolipoprotein A-I (apoA-I), and apolipoprotein B (apoB)] with VaD jointly using univariable MR (uvMR), multivariable MR (mvMR) and bidirectional two-sample MR methods. Then, the summary-data-based MR (SMR) and two-sample MR analysis were conducted to investigate the association of lipid-lowering drugs target genes expression (including HMGCR, PCSK9, NPC1L1, and APOB) and LDL-C level mediated by these target genes with VaD. The results of forward MR analyses found that genetically predicted HDL-C, LDL-C, TG, apoA-I, and apoB concentrations were not significantly associated with the risk of VaD (all p > 0.05). Notably, there was suggestive evidence for a causal effect of genetically predicted VaD on HDL-C via reverse MR analysis [odds ratio (OR), 0.997; 95% confidence interval (CI), 0.994−0.999; p = 0.022]. On the contrary, the MR results showed no significant relationship between VaD with LDL-C, TG, apoA-I, and apoB. The results for the SMR method found that there was no evidence of association for expression of HMGCR, PCSK9, NPC1L1, and APOB gene with risk of VaD. Furthermore, the result of MR analysis provided evidence for the decreased LDL-C level mediated by gene HMGCR reduced the risk of VaD (OR, 18.381; 95% CI, 2.092−161.474; p = 0.009). Oppositely, none of the IVW methods indicated any causal effects for the other three genes. Using genetic data, this study provides evidence that the VaD risk may cause a reduction of HDL-C level. Additionally, the finding supports the hypothesis that lowering LDL-C levels using statins may be an effective prevention strategy for VaD risk, which requires clinical trials to confirm this result in the future.

Cardiovascular Risk Management in Type 1 Diabetes

PURPOSE OF REVIEW

Type 1 diabetes mellitus (T1DM) is associated with increased mortality, with premature cardiovascular disease (CVD) a major factor. To date, research has identified multiple risk factors for this excess CVD liability. However, gaps remain in our understanding of the underlying mechanisms.

RECENT FINDINGS

T1DM is generally diagnosed at a young age. Since cardiovascular complications often only manifest at a later stage of life, there is generally less focus in earlier years on reducing CVD risk for affected individuals. This is an area that requires improvement as risk factors might be managed from earlier age to reduce later development of CVD. In this review, we discuss the evidence for cardiovascular risk factors, risk prediction models, candidate surrogate measurements and CVD risk management.

Narrative Review of Carotid disease and the kidney

Patients with chronic kidney disease (CKD) have an increased cardiovascular (CV) risk that is only in part explained by established risk factors. Carotid arteriosclerosis and atherosclerosis are increased in CKD, play a role in the causation of CV disease in these patients and can affect the progression of renal disease. The arterial stiffening process is evident even in CKD patients with a very mild reduction of glomerular filtration rate (GFR) whereas arterial thickening is evident in more advanced stages. Possible mechanisms include functional and structural alterations of the arterial wall. Arterial stiffness can mediate the effect of CKD on target organs (i.e., brain, kidney and heart). In this review we discuss the arterial phenotype of patients with CKD. This is characterized by increased common carotid artery stiffness and outward remodeling (enlargement and thickening of the arterial wall) and a normal/reduced stiffness paired with an inward remodeling (narrowing of the arterial wall) of muscular arteries. We also discuss the consequences of carotid dysfunction, including the involvement of large elastic arteries stiffness on ventricular-vascular coupling, the mechanisms linking carotid stiffening and increased cardio- and cerebrovascular risk in CKD patients, and the therapeutic options to improve carotid function.

Small Dense Low-Density Lipoprotein Cholesterol is a Potential Marker for Predicting Laser Treatment for Retinopathy in Diabetic Patients

Aim: We explored the superiority of small dense low-density lipoprotein cholesterol (sdLDL-C) as a marker for predicting not only the occurrence of cardiovascular (CV) events but also the need for laser treatment in patients with hypercholesterolemia and diabetic retinopathy.

Methods: We performed a sub-analysis of the intEnsive statin therapy for hyper-cholesteroleMic Patients with diAbetic retinopaTHY (EMPATHY) study (n=5042), in which patients were assigned randomly to intensive or standard statin therapy targeting low-density lipoprotein cholesterol ＜70 mg/dl or 100-120 mg/dl. Using the survival analysis, the risks for CV events and the need for laser treatment were evaluated according to the lipids one year after registration.

Results: The patients were 63±11 years old. LDL-C and sdLDL-C levels were 98±25 and 32±14 mg/dl, respectively, one year after registration. The sdLDL-C level had a strong positive correlation with apolipoprotein B level (r=0.83 at registration). SdLDL-C was a sensitive marker for predicting CV events when comparing among the quartiles according to sdLDL-C levels (hazard ratios: HR for quartiles 1-4 were 1.0, 1.4, 1.6, and 2.5, respectively;p for trend ＜0.01). Also, sdLDL-C was a sensitive marker for predicting the need for laser treatment among lipids (log rank,p=0.009), especially in patients with elderly (≧65 yrs) and obesity (BMI ≧25 kg/m²).

Conclusions: SdLDL-C is a sensitive target marker to predict cardiovascular events as well as the need for laser treatment in patients with hypercholesterolemia and diabetic retinopathy.

The Atherogenic Index of Plasma is Independently Associated with Symptomatic Carotid Artery Stenosis

INTRODUCTION

Small, dense low-density lipoprotein (sdLDL) is strongly associated with symptomatic carotid artery stenosis, but is not routinely evaluated in ischemic stroke patients. A method using the logarithmic transformation of the ratio of the plasma concentration of triglycerides (TGY) to HDL-cholesterol (HDL-C)[(Log[TGY/HDL-C])] has been described as a surrogate marker for sdLDL termed the atherogenic index of plasma (AIP).

OBJECTIVE

To determine if the AIP is independently associated with symptomatic carotid artery stenosis.

METHODS

We conducted a single center case-controlled study using a sample of ischemic stroke patients and compared risk factors of patients with and without symptomatic carotid artery stenosis. A multivariate logistic regression model was used to determine if the AIP divided into four quartiles was independently associated with symptomatic carotid artery stenosis. This model was compared to three other lipid models. Associations between non-lipid variables and the AIP were also identified.

RESULTS

31 cases of ischemic stroke due to symptomatic carotid artery stenosis and 236 controls of ischemic stroke not due to carotid artery stenosis were identified. Of the four lipid models assessed, only the model including the AIP (model 4) was found to be significantly associated with symptomatic carotid artery stenosis. The odd's ratio (OR) for quartile 3 was 3.82 (95% CI 1.03-14.17) and the OR for quartile 4 was 4.13 (95% CI 1.09-15.54) using quartile 1 as a reference. Metabolic syndrome was the only variable associated with the AIP (OR 5.06 95% CI 2.6-9.7).

CONCLUSION

At our single center, the AIP was the only lipid parameter independently associated with symptomatic carotid artery stenosis; and metabolic syndrome was independently associated with the AIP. The AIP may serve as a useful surrogate of sdLDL in patients with symptomatic carotid artery stenosis.

Association between carotid intima media thickness and small dense low-density lipoprotein cholesterol in acute ischaemic stroke

BACKGROUND

Intima-media thickness (IMT) and small dense low-density lipoprotein cholesterol (sdLDL-C) have been reported to be related to atherosclerosis and stroke. This study is trying to explore the association between IMT and sdLDL-C in Chinese acute ischaemic stroke (AIS) subjects.

METHODS

This study enrolled total 368 consecutive AIS patients and 165 non-AIS controls from November 2016 to February 2019. Mean IMT and carotid plaques were measured by using carotid ultrasonography method. Blood glucose and lipid parameters were measured by using an automatic biochemical instrument. SdLDL-C was detected by using the Lipoprint LDL system. IMT > 1.0 mm was defined as increased IMT. Plaque stability based on the nature of the echo was determined by ultrasound examination. Risk factors for IMT were identified by using multivariate logistic regression analysis. A logistic regression model was established to predict AIS risk. Python software (Version 3.6) was used for the statistical analysis of all data.

RESULTS

The carotid IMT, proportion of plaques, and the sdLDL-C, triglycerides (TG) and glucose levels were obviously higher in AIS patients than those in controls. SdLDL-C level in the IMT thickening group was higher than that in the normal IMT group. SdLDL-C and total cholesterol (TC) were risk factors for IMT, while sdLDL-C was an independent risk factor. The IMT value of the unstable plaque group was markedly higher than that of the stable plaque group. The predictive value of IMT for AIS was better than that of low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) but not as good as that of sdLDL-C. A logistic regression model was established to predict AIS risk. Additionally, carotid IMT and sdLDL-C were closely related to AIS severity and outcomes.

CONCLUSIONS

SdLDL-C and TC were risk factors for increased IMT, while sdLDL-C was an independent risk factor. A prediction model based on IMT and other variables was established to screen the population with high AIS risk.

Characterizing lipid profiles associated with asymptomatic intracranial arterial stenosis in rural-dwelling adults: A population-based study

BACKGROUND

Although individual lipid parameters have been frequently examined in association with asymptomatic intracranial arterial stenosis (aICAS), few population-based studies have investigated the lipid profiles associated with aICAS among Chinese adults.

OBJECTIVE

This study aims to characterize the lipid profiles associated with aICAS in rural-dwelling adults in China.

METHODS

This population-based study included 2027 persons who were aged ≥40 years and free of stroke. Data were collected via interviews, clinical examinations, and laboratory testing. We diagnosed aICAS by integrating transcranial color Doppler with magnetic resonance angiography. Data were analyzed using binary and multinomial logistic regression models.

RESULTS

Of the 2027 participants, 154 were detected with aICAS. The multiadjusted odds ratio (95% confidence interval) of aICAS was 1.41 (0.997-2.00) for high small dense low-density lipoprotein cholesterol, 1.44 (1.02-2.04) for high lipoprotein(a), 1.71 (1.21-2.44) for low apolipoprotein A-1, 1.43 (1.00-2.04) for low high-density lipoprotein cholesterol (HDL-C), 1.61 (1.14-2.27) for high apolipoprotein B/apolipoprotein A-1 ratio, 1.95 (1.38-2.76) for high low-density lipoprotein cholesterol/HDL-C ratio, and 1.51 (1.06-2.14) for high total cholesterol/HDL-C ratio. When severity of aICAS was analyzed, high levels of lipoprotein(a), small dense low-density lipoprotein cholesterol, and lipid ratios were significantly associated with an increased likelihood of moderate-to-severe aICAS (P < .05). An increasing number of abnormal lipid measurements was associated with an increased likelihood of aICAS (P for trend <.001).

CONCLUSION

These findings suggest that lipid profiles for aICAS among rural residents in China are characterized by high atherogenic cholesterol, low antiatherogenic cholesterol, and high ratios of atherogenic-to-antiatherogenic cholesterol or lipoproteins.

Cardiovascular Risk in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is associated with premature cardiovascular disease (CVD), but the underlying mechanisms remain poorly understood. The American Diabetes Association and the European Association for the Study of Diabetes recently updated their position statement on the management of type 2 diabetes mellitus (T2DM) to include additional focus on cardiovascular risk; improved management of risk factors in T1DM is also needed. There are important differences in the pathophysiology of CVD in T1DM and T2DM. Hyperglycaemia appears to have a more profound effect on cardiovascular risk in T1DM than T2DM, and other risk factors appear to cause a synergistic rather than additive effect, so achievement of treatment targets for all recognized risk factors is crucial to reducing cardiovascular risk. Here we discuss the evidence for addressing established cardiovascular risk factors, candidate biomarkers and surrogate measurements, and possible interventions.

Effects of Plasma Lipids and Statins on Cognitive Function

OBJECTIVE:

Dementia is the fourth most common cause of death in developed countries. The relationship between plasma lipids and cognitive function is complex and controversial. Due to the increasing life expectancy of the population, there is an urgent need to control vascular risk factors and to identify therapies to prevent and treat both cognitive impairment and dementia. Here, we reviewed the effects of plasma lipids and statins on cognitive function.

DATA SOURCES:

We searched the PubMed database for research articles published through November 2017 with key words including "plasma lipids," "hyperlipidemia," "hypercholesterolemia," "statins," and "cognition function."

STUDY SELECTION:

Articles were retrieved and reviewed to analyze the effects of plasma lipids and statins on cognitive function and the mechanisms underlying these effects.

RESULTS:

Many studies have examined the relationship between plasma lipids and cognitive function, but no definitive conclusions can be drawn. The mechanisms involved may include blood-brain barrier injury, the influence on small blood vessels in the brain, the influence on amyloid deposition, and a neuroprotective effect. To date, most studies of statins and cognition have been observational, with few randomized controlled trials. Therefore, firm conclusions regarding whether mid- or long-term statin use affects cognition function and dementia remain elusive. However, increasing concern exists that statins may be a causative factor for cognitive problems. These adverse effects appear to be rare and likely represent a yet-to-be-defined vulnerability in susceptible individuals.

CONCLUSIONS:

The association between plasma lipids and cognition, the mechanism of the influence of plasma lipids on cognitive function, and the association between statins and cognitive function are complex issues and currently not fully understood. Future research aimed at identifying the mechanisms that underlie the effects of plasma lipids and statins on cognition will not only provide important insight into the causes and interdependencies of cognitive impairment and dementia, but also inspire novel strategies for treating and preventing these cognitive disorders.

Small dense low density lipoprotein-cholesterol and cholesterol ratios to predict arterial stiffness progression in normotensive subjects over a 5-year period

BACKGROUND

Small dense low density lipoprotein-cholesterol (sdLDL-C), cholesterol ratios and carotid-femoral pulse wave velocity (cf-PWV) impart risk for all-cause morbidity and mortality independently of conventional cardiovascular disease (CVD) risk factors. This study was designed to identify feasible indicators for predicting arterial stiffness progression.

METHODS

We followed up 816 normotensive participants without diabetes or CVD for nearly 5.0 years. Cholesterol parameters, ratios and other clinical and laboratory data were collected at baseline. cf-PWV were measured at baseline and the end of follow-up.

RESULTS

PWV progression subjects had higher levels of PWV parameters, sdLDL-C and TG/HDL-C ratio. sdLDL-C and TG/HDL-C were significantly correlated with all PWV parameters. Multiple regression models showed that sdLDL-C was closely associated with follow-up PWV (β = 0.222, p < 0.001) and △PWV (β = 0.275, p < 0.001). TG/HDL-C was only one cholesterol ratios that associated with all PWV parameters. sdLDL-C (OR = 2.070, 95%CI: 1.162 to 3.688, p = 0.014) and TG/HDL-C (OR = 1.355, 95%CI: 1.136 to 1.617, p = 0.001) could significantly determine the progression of PWV after correction for covariates. High sd-LDL-C quantiles subjects were more likely to develop arterial stiffness progression than low quantiles (Tertiles 3 vs Tertiles1, RR = 2.867, 95%CI: 1.106 to 7.434, p = 0.03).

CONCLUSION

We founded that sdLDL-C and TG/HDL-C ratio can independently predict arterial stiffness progression in normotensive subjects, and high level sdLDL-C and TG/HDL-C ratio were associated with a higher risk of arterial stiffness.

Apolipoprotein B is associated with carotid atherosclerosis progression independent of individual cholesterol measures in a 9-year prospective study of Multi-Ethnic Study of Atherosclerosis participants

BACKGROUND

High blood cholesterol contributes to atherosclerosis, yet reliance on the lipid panel alone may mischaracterize individuals with elevated lipoprotein particle numbers.

OBJECTIVE

The aim of the article was to determine whether elevated lipoprotein or apolipoprotein measures are associated with carotid atherosclerosis and plaque progression independent of cardiovascular (CV) risk factors including standard lipids in a subcohort of 2228 Multi-Ethnic Study of Atherosclerosis participants.

METHODS

Ultrasonography assessed carotid artery plaque and common carotid intima-media thickness (cIMT) at baseline and after a median period of 9.4 years. Nuclear magnetic resonance spectroscopy estimated lipoprotein particle concentrations. Apolipoprotein B (ApoB) and apolipoprotein A-I were measured using an automated immunoassay. Regression analysis determined associations of apolipoprotein and lipoprotein measurements with cIMT and relative risk regression determined associations with carotid plaque progression.

RESULTS

After adjustment for typical CV risk factors, individuals in top quartiles of ApoB, ApoB/apolipoprotein A-I, low-density lipoprotein particles (LDL-P), small LDL-P, and total LDL-P/high-density lipoprotein (HDL) particles showed similar risks of carotid plaque and cIMT progression as LDL-C, non-HDL cholesterol (HDL-C), total cholesterol (TC), and TC/HDL-C. A significant association with plaque progression remained in the top ApoB quartile after further adjustment for LDL-C (P = .02) or TC + HDL-C (P = .04), but was nonsignificant when adjusted for all lipid covariates (P = .086). Those in the top quartile of small LDL-P concentrations showed greater cIMT progression than those in the referent after adjustment for LDL-C, but this was nonsignificant after adjustment for TC + HDL-C.

CONCLUSION

When coupled with evidence that apolipoprotein testing identifies lipid-lipoprotein discordance, these findings suggest that ApoB and small LDL-P provide atherosclerosis risk information that is not revealed by typical CV risk factors.

Hypertriglyceridemia is a major factor associated with elevated levels of small dense LDL cholesterol in patients with metabolic syndrome

BACKGROUND

We aimed to determine the major contributing component of metabolic syndrome (MetS) that results in an elevated small dense LDL cholesterol (sdLDL-C) concentration and sdLDL-C/LDL-C ratio.

METHODS

Four hundred and forty-seven subjects (225 men; 222 women) with MetS were randomly selected from the Korean Metabolic Syndrome Research Initiatives-Seoul cohort study. Age- and sex-matched healthy controls (181 men; 179 women) were also randomly selected from the same cohort.

RESULTS

A comparison of the median values of the sdLDL-C concentration between subgroups, divided according to whether subjects met or did not meet the criteria for each MetS component in patients with MetS, revealed a significant difference in the sdLDL-C concentration only between subgroups divided according to whether subjects met or did not meet the triglyceride (TG) criteria (P<0.05 for each gender). The TG level showed a good correlation with sdLDL-C concentration (correlation coefficients [r]=0.543 for men; 0.653 for women) and the sdLDL-C/LDL-C ratio (r=0.789 for men; 0.745 for women). Multiple linear regression analyses conducted for the MetS group concordantly identified TG as one of the most significant contributors to sdLDL-C concentration (β=0.1747±0.0105, P<0.0001) and the sdLDL-C/LDL-C ratio (β=6.9518±0.3011, P<0.0001).

CONCLUSIONS

Among five MetS components, only the abnormal TG level was a differentiating factor for sdLDL-C concentration and sdLDL-C/LDL-C ratio. These results were reproducible in both genders, with or without MetS.

The Association Between Obesity and Hostility: The Mediating Role of Plasma Lipids

OBJECTIVE

Recent research indicates an association between obesity and psychopathology status, the nature of which remains unclear. We evaluated the mediating role of biochemical disturbances in this association among a treatment-seeking sample of obese individuals.

METHOD

The study enrolled 143 consecutive overweight and obese individuals (mean age 35±9 y) and 143 normal-weight controls (mean age 34±9 y), matched by age and sex. We measured psychopathology features using the Symptom Checklist 90-Revised (SCL-90-R), a standardized self-evaluation rating scale, and biochemical parameters (plasma cholesterol, triglyceride, and fasting glucose levels) of all participants. Nonlinear regression models were used to estimate the associations among obesity, psychopathology, and biochemical factors.

RESULTS

Obesity was associated positively and significantly (P<0.05) with all of the SCL-90-R subscales, with the exception of anxiety and phobic anxiety, as well as with levels of plasma glucose, cholesterol (P<0.01), and triglycerides (P<0.001). Tests for mediation showed that obesity was significantly associated, for the mediators of plasma cholesterol [parameter estimate=-0.033, P<0.05] and triglycerides (parameter estimate=-0.059, P<0.05), only with hostility (parameter estimate=-0.024, P<0.05 and parameter estimate=-0.041, P<0.05, respectively).

CONCLUSIONS

Our data suggest that biological substrates that are critically related to obesity, such as dyslipidemia, may mediate, at least in part, the association between obesity and hostility.

The improvement of large High-Density Lipoprotein (HDL) particle levels, and presumably HDL metabolism, depend on effects of low-carbohydrate diet and weight loss

Depressed levels of atheroprotective large HDL particles are common in obesity and cardiovascular disease (CVD). Increases in large HDL particles are favourably associated with reduced CVD event risk and coronary plaque burden. The objective of the study is to compare the effectiveness of low-carbohydrate diets and weight loss for increasing blood levels of large HDL particles at 1 year. This study was performed by screening for body mass index (BMI) and metabolic syndrome in 160 consecutive subjects referred to our out-patient Metabolic Unit in South Italy. We administered dietary advice to four small groups rather than individually. A single team comprised of a dietitian and physician administered diet-specific advice to each group. Large HDL particles at baseline and 1 year were measured using two-dimensional gel electrophoresis. Dietary intake was assessed via 3-day diet records. Although 1-year weight loss did not differ between diet groups (mean 4.4 %), increases in large HDL particles paralleled the degree of carbohydrate restriction across the four diets (p<0.001 for trend). Regression analysis indicated that magnitude of carbohydrate restriction (percentage of calories as carbohydrate at 1 year) and weight loss were each independent predictors of 1-year increases in large HDL concentration. Changes in HDL cholesterol concentration were modestly correlated with changes in large HDL particle concentration (r=0.47, p=.001). In conclusion, reduction of excess dietary carbohydrate and body weight improved large HDL levels. Comparison trials with cardiovascular outcomes are needed to more fully evaluate these findings.

Correlation between small dense low-density lipoprotein cholesterol and carotid artery intima-media thickness in a healthy Chinese population

BACKGROUND

Small dense low-density lipoprotein cholesterol (sdLDL-C) concentration was useful in the assessment of the presence of cardiovascular diseases (CVD) and its severity. We examined whether SdLDL-C is more closely associated with carotid artery intima-media thickness (CA-IMT), a surrogate measure of atherosclerosis, than LDL-C and traditional CVD risk factors in Chinese healthy subjects.

METHODS

We measured CA-IMT, blood pressure (BP), sdLDL-C, glucose metabolism and lipid in 183 native Chinese healthy subjects. CA-IMT was assessed by ultrasonography, and sdLDL-C concentrations were measured by a homogenous assay. Pearson's correlation coefficient analyses and Multiple regression analyses were used to examine the relationships between CA-IMT values and other clinical variables.

RESULTS

The sdLDL-C level was significantly higher in males than in females (p <0.05) and there was an age effect on sdLDL-C (p <0.05). When the effects of age, gender and other traditional CVD risk factors were adjusted using multiple regression analysis. CA-IMT remained significantly associated with sdLDL-C(β = 0.437, p <0.001).

CONCLUSIONS

There are gender and age differences in sdLDL-C levels among a healthy Chinese population. Moreover, we found adjusted traditional CVD risk factors such as higher age, male sex, and other traditional CVD risk factors, the association between CA-IMT and SdLDL-C remained significant. sdLDL-C is may be a useful predictor in the assessment of CA-IMT in Chinese population.

Cholesterol Metabolism in CKD

Patients with chronic kidney disease (CKD) have a substantial risk of developing coronary artery disease. Traditional cardiovascular disease (CVD) risk factors such as hypertension and hyperlipidemia do not adequately explain the high prevalence of CVD in CKD. Both CVD and CKD are inflammatory states and inflammation adversely affects lipid balance. Dyslipidemia in CKD is characterized by elevated triglyceride levels and high-density lipoprotein levels that are both decreased and dysfunctional. This dysfunctional high-density lipoprotein becomes proinflammatory and loses its atheroprotective ability to promote cholesterol efflux from cells, including lipid-overloaded macrophages in the arterial wall. Elevated triglyceride levels result primarily from defective clearance. The weak association between low-density lipoprotein cholesterol level and coronary risk in CKD has led to controversy over the usefulness of statin therapy. This review examines disrupted cholesterol transport in CKD, presenting both clinical and preclinical evidence of the effect of the uremic environment on vascular lipid accumulation. Preventative and treatment strategies are explored.

Relationship between carotid artery intima-media thickness and small dense low-density lipoprotein cholesterol concentrations measured by homogenous assay in Japanese subjects

BACKGROUND

Small dense low-density lipoprotein cholesterol (sdLDL-C) concentrations correlate more strongly with coronary heart disease than other LDL-C and large LDL particle concentrations. We investigated the association between carotid artery intima-media thickness (IMT) and sdLDL-C concentrations in Japanese subjects.

METHODS

Carotid artery IMT, blood pressure (BP), fasting plasma sdLDL-C, glucose metabolism, lipid, and C-reactive protein concentrations were measured in 97 native Japanese subjects. Carotid artery IMT was assessed by ultrasonography, and sdLDL-C concentrations were measured by a homogenous assay. Pearson's correlation coefficient analyses and multiple regression analyses were used to examine the relationships between carotid artery IMT values, sdLDL-C values, and other clinical variables.

RESULTS

After multiple regression analysis, including age, sex, body mass index, systolic BP, diastolic BP, fasting plasma glucose, HbA1c, estimated glomerular filtration rate (eGFR), total-C, high-density lipoprotein (HDL)-C, triglyceride, LDL-C, non-HDL-C, large buoyant LDL-C, and sdLDL-C, carotid artery IMT remained significantly associated with age, systolic BP, diastolic BP, and sdLDL-C, whereas sdLDL-C remained significantly associated with age, total-C, HDL-C, triglycerides, and carotid artery IMT.

CONCLUSIONS

When measured by a homogenous assay, carotid artery IMT may have a closer relationship with sdLDL-C concentrations than other lipid parameters in Japanese subjects. sdLDL-C may be a potentially useful risk marker when assessing carotid artery IMT in Japanese subjects.

Low-density-lipoprotein particle size predicts a poor outcome in patients with atherothrombotic stroke

BACKGROUND AND PURPOSE

Low-density lipoprotein (LDL) particle size is considered to be one of the more important cardiovascular risk factors, and small LDL particles are known to have atherogenic potential. The aim of this study was to determine whether LDL particle size is associated with stroke severity and functional outcome in patients with atherothrombotic stroke.

METHODS

Between January 2009 and May 2011, 248 patients with first-episode cerebral infarction who were admitted to our hospital within 7 days after symptom onset were prospectively enrolled. LDL particle size was measured using the nondenaturing polyacrylamide gradient gel electrophoresis assay. Stroke severity was assessed by applying the National Institutes of Health Stroke Scale (NIHSS) at admission. Functional outcome was investigated at 3 months after the index stroke using the modified Rankin Scale (mRS), and poor functional outcome was defined as an mRS score of ≥3.

RESULTS

The LDL particle size in the 248 patients was 25.9±0.9 nm (mean±SD). LDL particle size was inversely correlated with the degree of cerebral artery stenosis (p=0.010). Multinomial multivariate logistic analysis revealed that after adjustment for age, sex, and variables with p<0.1 in univariate analysis, LDL particle size was independently and inversely associated with stroke severity (NIHSS score ≥5; reference, NIHSS score 0-2; odds ratio=0.38, p=0.028) and poor functional outcome (odds ratio=0.44, p=0.038).

CONCLUSIONS

The results of this study demonstrate that small LDL particles are independently correlated with stroke outcomes. LDL particle size is thus a potential biomarker for the prognosis of atherothrombotic stroke.

Additive effects of postchallenge hyperglycemia and low-density lipoprotein particles on the risk of arterial stiffness in healthy adults

Background

To determine the effects of post-challenge hyperglycemia potentiate low-density lipoprotein cholesterol (LDL) particles on the risk of arterial stiffness in non-diabetic adults.

Methods

During 2009–2011, 592 adults without clinical diabetes (fasting glucose <7.0 mmol/L) or known coronary heart disease or stroke were recruited. All subjects underwent standard 75-g oral glucose tolerance test (OGTT) after overnight fasting. The glucose area under curve (GluAUC) after OGTT was defined as the postchallenge glucose load. Levels of LDL-C and small dense LDL-C (sdLDL-C) were measured. Arterial stiffness in terms of brachial–ankle pulse wave velocity (baPWV) was also measured.

Results

The baPWV in tertile distributions were significantly associated with all conventional cardiovascular risk factors, LDL-C, and sdLDL-C. Multivariate logistic regression analyses revealed that LDL-C (or sdLDL-C) combined with one of the seven glycemic indices (glucose levels at 0, 30, 60, 90, and 120 min; GluAUC; HbA1C) was associated with arterial stiffness after covariates being adjusted. Further interaction analyses showed only concurrent higher levels of both glycemic indices and atherogenic LDL-C or sdLDL-C have significant risk for arterial stiffness.

Conclusions

Additive effects of both postchallenge hyperglycemia and LDL subclass particles potentiate the risk of arterial stiffness. The adverse joint effects of hyperlipidemia and postchallenge hyperglycemia on subclinical cardiovascular function provide important information in primary prevention of cardiovascular disease in subjects without clinical diabetes.

Immobilization of sodium alginate sulfates on polysulfone ultrafiltration membranes for selective adsorption of low-density lipoprotein

A novel method for the immobilization of sodium alginate sulfates (SAS) on polysulfone (PSu) ultrafiltration membranes to achieve selective adsorption of low-density lipoprotein (LDL) was developed, which involved the photoinduced graft polymerization of acrylamide on the membrane and the Hofmann rearrangement reaction of grafted acrylamide followed by chemical binding of SAS with glutaraldehyde. The surface modification processes were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterization. Zeta potential and water contact angle measurements were performed to investigate the surface charge and wettability of the membranes. An enzyme-linked immunosorbent assay was used to measure the binding of LDL on plain and modified PSu membranes. It was found that the PSu membrane immobilized with sodium alginate sulfates (PSu-SAS) greatly enhanced the selective adsorption of LDL from protein solutions and the absorbed LDL could be easily eluted with sodium chloride solution, indicating a specific and reversible binding of LDL to SAS, mainly driven by electrostatic forces. Furthermore, the PSu-SAS membrane showed good blood compatibility as examined by platelet adhesion. The results suggest that the PSu-SAS membranes are promising for application in simultaneous hemodialysis and LDL apheresis therapy.

Cholesterol forms and traditional lipid profile for projection of atherogenic dyslipidemia: lipoprotein subfractions and erythrocyte membrane cholesterol

Atherogenic dyslipidemia characterized by abnormal changes in plasma lipid profile such as low high-density lipoprotein (HDL) and increased triglyceride (TG) levels is strongly associated with atherosclerotic diseases. We aimed to evaluate the levels of pro- and antiatherogenic lipids and erythrocyte membrane cholesterol (EMC) content in normo- and dyslipidemic subjects to investigate whether EMC content could be a useful marker for clinical presentation of atherogenic dyslipidemia. Low-density lipoprotein (LDL), HDL and their subfraction levels and erythrocyte lipid content were determined in 64 normolipidemic (NLs), 42 hypercholesterolemic (HCs) and 42 mixed-type dyslipidemic subjects (MTDs). Plasma atherogenic lipid indices [small–dense LDL (sdLDL)/less-dense HDL (LHDL), TC/HDL-C, TG/HDL-C and Apo B/AI] were higher in MTDs compared to NLs (p < 0.001). The highest sdLDL level was observed in HCs (p < 0.01). Despite a slight increase in EMC level in dyslipidemic subgroups, the difference was not statistically significant. A significant negative correlation, however, was observed between EMC and sdLDL/LHDL in HCs (p < 0.035, r = −0.386). Receiver operating characteristic curves to predict sdLDL level showed that TG and EMC levels had higher area under curve values compared to other parameters in HCs. We showed that diameters of larger LDL and HDL particles tend to shift toward smaller values in MTDs. Our results suggest that EMC content and TG levels may be a useful predictor for sdLDL level in hypercholesterolemic patients.

Correlation between serum levels of small, dense low-density lipoprotein cholesterol and carotid stenosis in cerebral infarction patients >65 years of age

BACKGROUND

We studied the relationship between serum levels of small, dense low-density lipoprotein cholesterol (sdLDL-C) and carotid stenosis in elderly patients with ischemic cerebral infarction.

METHODS

All patients >65 years of age with newly diagnosed ischemic cerebral infarction were enrolled. None received statins before enrollment. Patients were examined for carotid stenosis by ultrasound color Doppler, and serum sdLDL-C levels were measured using an automated method.

RESULTS

The 149 patients were distributed according to their carotid stenosis as without (n = 61) or with mild (n = 30), moderate (n = 34), or severe (n = 24) carotid stenosis. sdLDL-C levels increased significantly with increasing stenosis severity (0.54 ± 0.19, 0.71 ± 0.18, 0.98 ± 0.19, and 1.32 ± 0.17 mmol/L, respectively). Spearman rank correlation analysis revealed that sdLDL-C levels and degree of carotid stenosis were positively correlated (r = 0.411; P < 0.001). Male sex, body mass index, diabetes, hypertension, hyperlipidemia, drinking, smoking, and sdLDL-C levels were positively correlated with carotid stenosis. Logistic regression analysis revealed that sdLDL-C levels are an independent risk factor of carotid stenosis (P = 0.041).

CONCLUSIONS

sdLDL-C levels are positively correlated with the severity of carotid stenosis, and are an independent risk factor in elderly patients with ischemic cerebral infarction.

Association between small dense LDL and early atherosclerosis in a sample of menopausal women

The association between small dense LDL particles and early atherosclerosis has been evaluated in a sample of middle-aged women. We analysed the relation between sd-LDL and common carotid intima media thickness in 228 menopausal women. LDL separation was performed by Lipoprint System: 7 LDL subfractions were obtained, mean LDL size and LDL score (% of sd-LDL) were calculated. Multivariate analysis showed a significant association between IMT (≥ 1.30 mm) and mean LDL size after controlling for age (OR 7.80; 95% CI 1.47-41.39; p = 0.016 for mean LDL particle size). IMT remained significantly related to mean LDL particle size after controlling for age and Apo B. In a subsequent multivariate analysis, after controlling for age, IMT (≥ 1.30 mm) was significantly related to LDL score (OR 12.15; 95% CI 1.29-114.36; p = 0.029 for LDL score), or age and Apo B (OR 10.13; 95% CI 1.07-95.71; p = 0.043 for LDL score). Our results suggest an association between sd-LDL and IMT, independently of age and Apo B. This data may indicate that sd-LDL are markers of early carotid atherosclerosis, and suggest that measurement of sd-LDL-C gives useful information in the risk assessment for atherosclerotic disease in menopausal women.

Higher leukocyte subpopulation counts in healthy smoker industrial workers than in nonsmoker industrial workers: possible health consequences

OBJECTIVES

Cigarette smoke contains free radicals, which cause injury to endothelial cells and oxidize bioactive components in the blood. Neutrophils, a subpopulation of leukocytes, contain the enzyme myeloperoxidase that mediates production of hypochlorous acid during oxidative stress. In this study, we investigated whether smoker industrial workers had significantly higher neutrophil counts than nonsmoker industrial workers.

DESIGN AND METHODS

We collected blood samples from 183 apparently healthy male and 30 female industrial workers. We obtained blood cell counts, measured the concentration of plasma aminothiols and determined the concentration of serum and erythrocyte folate and serum vitamin B12 in the samples.

RESULTS

Smoker industrial workers had significantly higher neutrophil, lymphocyte, monocyte, eosinophil and basophil counts than nonsmoker industrial workers (p < 0.0001, p < 0.0001, p < 0.0001, p < 0.0001 and p = 0.01, respectively). Mean corpuscular volume and mean corpuscular hemoglobin in smoker industrial workers were higher than in nonsmoker industrial workers (p = 0.001 and p = 0.03).

CONCLUSION

Our study demonstrates that smoker industrial workers have higher neutrophil counts than nonsmoker industrial workers. Therefore, our observations suggest that smokers may become more easily prone to chronic inflammation than nonsmokers. About 84% of the study participants were male subjects; therefore, our findings may be more representative for men than women.

Regulation of low-density lipoprotein subfractions by carbohydrates

PURPOSE OF REVIEW

This article aims at reviewing the recent findings that have been made concerning the crosstalk of carbohydrate metabolism with the generation of small, dense low-density lipoprotein (LDL) particles, which are known to be associated with an adverse cardiovascular risk profile.

RECENT FINDINGS

Studies conducted during the past few years have quite unanimously shown that the quantity of carbohydrates ingested is associated with a decrease of LDL particle size and an increase in its density. Conversely, diets that aim at a reduction of carbohydrate intake are able to improve LDL quality. Furthermore, a reduction of the glycaemic index without changing the amount of carbohydrates ingested has similar effects. Diseases with altered carbohydrate metabolism, for example, type 2 diabetes, are associated with small, dense LDL particles. Finally, even the kind of monosaccharide the carbohydrate intake consists of is important concerning LDL particle size: fructose has been shown to alter the LDL particle subclass profile more adversely than glucose in many recent studies.

SUMMARY

LDL particle quality, rather than its quantity, is affected by carbohydrate metabolism, which is of clinical importance, in particular, in the light of increased carbohydrate consumption in today's world.

Changes in small dense low-density lipoprotein levels following acute coronary syndrome

Low-density lipoprotein (LDL), especially small dense LDL (sdLDL), plays a role in atherogenesis. We compared baseline sdLDL levels between healthy controls and patients with acute coronary syndrome (ACS). Blood samples were taken from patients diagnosed with myocardial infarction ([MI] n = 104) and unstable angina ([UA] n = 100). Both sdLDL and high-sensitivity C-reactive protein (hsCRP) levels were determined on admission and in the next 24 hours after the onset of symptoms. Baseline concentration of sdLDL was significantly higher in patients presenting with ACS than controls (P < .05). In the 24 hours following ACS, the sdLDL levels decreased insignificantly in both groups of patients with ACS (P > .05). The changes in sdLDL values were not significantly different between MI and UA participants (P > .05). Patients with ACS have higher concentration of sdLDL compared with the controls.

Associations between small dense LDL, HDL subfractions (HDL2, HDL3) and risk of atherosclerosis in Japanese-Americans

AIM

Small dense low-density lipoprotein (sdLDL) has been suggested to be more atherogenic than large buoyant LDL. High-density lipoprotein (HDL) consists of two major subfractions (HDL2, HDL3), and just as controversy remains regarding which of the two is the more powerful negative risk factor for atherosclerosis, associations between sdLDL and these HDL subfractions are unclear.

METHODS

We measured sdLDL cholesterol (sdLDL-C), HDL2 cholesterol (HDL2-C) and HDL3 cholesterol (HDL3-C) by a newly developed method in 481 Japanese-Americans who were not using lipid-lowering medication, and examined the associations of these cholesterol concentrations with variables related to atherosclerosis.

RESULTS

In multivariate analysis, sdLDL-C was positively correlated with the body mass index (BMI), fasting glucose and insulin, 2-h glucose, HOMA-IR, high sensitivity C-reactive protein (hsCRP), and carotid artery intima-media thickness (IMT) after adjustment for age and sex. In particular, sdLDL-C was positively correlated with IMT, even after adjustment for sex, age, smoking status, hypertension, diabetes mellitus and hsCRP. HDL2-C was more closely inversely correlated than total HDL-C with BMI, fasting glucose and insulin, 2-h glucose, HOMA-IR, and hsCRP, whereas HDL3-C was not correlated with these factors. Additionally, HDL2-C was more closely correlated than total HDL-C or HDL3-C with sdLDL-C, LDL-C, triglycerides (TG), and apolipoprotein B (apoB).

CONCLUSIONS

SdLDL-C was closely associated with insulin resistance and glucose tolerance, lending credence to its potential as a useful risk marker in assessing carotid artery IMT and the present degree of atherosclerosis in Japanese-Americans. The findings also suggest that subjects with higher HDL2-C levels were better protected from atherosclerosis.

Negatively charged low-density lipoprotein is associated with atherogenic risk in hypertensive patients

Negatively charged low-density lipoprotein (LDL), generated via multiple processes such as oxidation, acetylation, or glycosylation, plays a key role in the initiation and progression of atherosclerosis and related diseases. Anion-exchange high-performance liquid chromatography (AE-HPLC) can subfractionate LDL into LDL-1, LDL-2, and LDL-3 based on LDL particle charge, but the clinical significance of LDL subfractions has not yet been elucidated. The aim of this study was to determine the clinical significance of these fractions with particular regard to atherogenic risk in hypertensive patients. Ninety-eight patients with essential hypertension (age 67.0 ± 10.7 years; 54 males) were enrolled in the present study. The relationships between LDL subfractions and atherogenic risk factors, including lipid profiles, blood pressure and plasma 8-isoprostane as a marker of oxidative stress, were examined. LDL-1 levels were significantly and negatively correlated with body mass index (r = -0.384, p < 0.001), systolic blood pressure (r = -0.457, p < 0.001), non-high-density lipoprotein cholesterol levels (r = -0.457, p < 0.001) and 8-isoprostane levels (r = -0.415, p < 0.001). LDL-3, which is the most negatively charged fraction of total LDL, was significantly and positively correlated with these parameters (r = 0.267, 0.481, 0.357, and 0.337, respectively). LDL-1 levels were significantly lower (p < 0.001), and LDL-2 and LDL-3 levels were significantly higher (each p < 0.001) in patients with poorly controlled hypertension than in patients with well-controlled hypertension. In addition, an increase in the total number of traditional risk factors at time of study participation, but not previous diagnosis, was associated with a decrease in LDL-1 levels and increases in LDL-2 and LDL-3 levels. These data suggest that LDL subfractions are associated with multiple atherogenic risk factors and that treatment to modify these risk factors could result in changes in LDL subfraction levels. In conclusion, LDL subfractions isolated by AE-HPLC may represent a marker of atherogenic risk in patients with hypertension.

Dyslipidemia as a contributory factor in etiopathogenesis of diabetic neuropathy

OBJECTIVES

The pathogenesis of neuropathy in type 2 diabetes mellitus is multifactorial.Dyslipidemia may contribute to the development of diabetic neuropathy. This study aimed to assess the atherogenic lipid indices in type 2 diabetic patients with neuropathy.

MATERIAL AND METHODS

Fifty-one patients with type 2 diabetes mellitus and 31 healthy subjects were studied in the Unit of Neurophysiology at the University Hospital of Medical College, Al-Nahrin University in Baghdad, Iraq, from January 2002 to January 2003. Neuropathy total symptom score (NTSS), neuropathy impairment score in the lower leg (NIS-LL), and electrophysiological study of sensory (ulnar and sural) and motor (ulnar and common peroneal) nerves were used to assess nerve function. Fasting venous blood was obtained from each participant for determination of lipid profile and atherogenic lipid ratios.

RESULTS

The frequency of high blood pressure was significantly higher in neuropathic patients. The electrophysiology study revealed significant decrease in conduction velocity of ulnar (sensory and motor components), sural, and common peroneal nerves. The minimum F-wave latency of motor nerve was significantly prolonged. Among the lipid fractions, only high-density lipoprotein-cholesterol was significantly reduced by 14% of healthy participant's value. Atherogenic lipid ratios were significantly higher in diabetic patients than corresponding healthy ratios.

CONCLUSION

Metabolic lipid disturbances in terms of atherogenicity co-existwith neuropathy in type 2 diabetes mellitus, irrespective of duration of disease.

A candidate gene study revealed sex-specific association between the OLR1 gene and carotid plaque

BACKGROUND AND PURPOSE

Sex differences have been recognized in stroke risk; however, the sex-dependent genetic contribution to stroke is unclear. We sought to examine the sex-dependent associations between genes involved in lipid metabolism and carotid atherosclerotic plaque, a subclinical precursor of stroke.

METHODS

For the Genetic Determinant of Subclinical Carotid Disease study, 287 Dominicans ascertained through the Northern Manhattan Study were examined for carotid plaque using high-resolution ultrasound. Sixty-four single nucleotide polymorphisms (SNPs) in 11 lipid-related genes were genotyped. Plaque presence and plaque subphenotypes, including multiple, thick, irregular, and calcified plaque, were analyzed. First, the interaction between each SNP and sex was evaluated for association with each plaque phenotype using multiple logistic regression and controlling for age, smoking, and the main effects of sex and SNP. For SNPs with suggestive evidence for interaction with sex (P<0.1 for the interaction term), stratification analysis by sex was performed to evaluate the sex-specific association between the SNP and plaque phenotypes.

RESULTS

The most compelling finding is with the missense SNP rs11053646 (K167N) in the OLR1 gene, which encodes lectin-like oxidized low-density lipoprotein receptor. Stratification analysis revealed a strong association between rs11053646 and all plaque phenotypes in women (OR, 2.44 to 5.86; P=0.0003 to 0.0081) but not in men (OR, 0.85 to 1.22; P=0.77 to 0.92).

CONCLUSIONS

Genetic variation in genes involved in lipid metabolism may have sex-dependent effects on carotid plaque burden. Our findings provide a plausible biological basis underlying the sex difference in cardiovascular risk.

Ruminant-produced trans-fatty acids raise plasma total and small HDL particle concentrations in male Hartley guinea pigs

Although trans-fatty acid (tFA) intake has been positively associated with coronary heart disease (CHD), the relative effect of consuming industrially produced (IP)- compared with ruminant-produced (RP)-tFA on CHD risk factors is unclear. This study was designed to examine the effects of feeding partially hydrogenated vegetable oil (PHVO), IP-tFA source, and butter oil (BO), RP-tFA source, on the development of atherosclerosis and risk factors associated with CHD. Forty-eight male Hartley guinea pigs were fed a hypercholesterolemic diet containing (9% by weight) PHVO, BO, coconut oil (CO; positive control), or soybean oil (SO; negative control) for 8 or 12 wk (n = 6/group). Morphological analysis revealed that none of the groups developed atherosclerosis. Plasma and hepatic lipids did not differ between the tFA groups, but total and small HDL particles were significantly higher in the BO group than in the PHVO group and mean HDL particle size was significantly smaller in the BO group than in the PHVO group. Compared with the other treatment groups, the SO treatment resulted in significantly lower total cholesterol (TC) and LDL cholesterol in plasma, whereas hepatic TC was significantly higher in the SO group than in the other treatment groups. Plasma and hepatic cholesterol concentrations did not differ between the tFA and CO treatments. These results demonstrate that when fed at a high dose, IP- and RP-tFA had the same effect on established CHD risk factors in male Hartley guinea pigs. The effects of RP-tFA on HDL particle sizes and concentrations warrant further investigation.

Blood compatibility and permeability of heparin-modified polysulfone as potential membrane for simultaneous hemodialysis and LDL removal

Heparin was covalently immobilized on PSf membranes to obtain a dialysis membrane with high affinity for LDL. WCA and streaming potential measurements were performed to investigate wettability and surface charge of the membranes. The morphology of the membranes was investigated by SEM. An ELISA was used to measure the adsorption and desorption of LDL on plain and modified PSf. Blood compatibility was studied by measurement of thrombin time, partial thromboplastin time, kallikrein activity and platelet adhesion. It was found that the blood compatibility of the membrane was improved by covalent immobilization of heparin at its surface. However, PSf-Hep membrane showed higher flux recovery after BSA solution filtration, which revealed antifouling property of PSf-Hep membranes.

Lipoprotein subfractions and cardiovascular disease risk

PURPOSE OF REVIEW

Subfractions of LDL and HDL defined by differences in particle size and density have been associated to varying degrees with risk of cardiovascular disease (CVD). Assessment of these relationships has been clouded by lack of standardization among the various analytic methodologies as well as the strong correlations of the subfractions with each other and with standard lipid and lipoprotein risk markers. This review summarizes the properties of the major LDL and HDL particle subclasses, and recent evidence linking their measurement with risk of atherosclerosis and CVD.

RECENT FINDINGS

Several recent studies have shown independent relationships of levels of LDL and HDL-size subclasses to risk of both coronary artery and cerebrovascular disease. However, the two largest studies, employing nuclear magnetic resonance and ion mobility, respectively, did not find evidence that these measurements improved risk assessment compared with standard lipoprotein assays. In the latter study, principal component analysis was used to group multiple subfraction measurements into three distinct and statistically independent clusters that were related both to cardiovascular outcomes and to genotypes that may reflect underlying metabolic determinants.

SUMMARY

Although there is as yet inconclusive evidence as to the extent to which LDL and HDL subfraction measurements improve clinical assessment of CVD risk beyond standard lipid risk markers, recent studies suggest that more refined analyses of lipoprotein subspecies may lead to further improvements in CVD risk evaluation and particularly in identification of appropriate targets for therapeutic intervention in individual patients.

Immobilization of heparin on polysulfone surface for selective adsorption of low-density lipoprotein (LDL)

A versatile method was developed to immobilize heparin covalently on polysulfone sheets (PSu) to achieve selective adsorption of low-density lipoprotein (LDL). This was achieved by activation of PSu with successive treatments of chlorodimethyl ether and ethylenediamine, and subsequent chemical binding of heparin with bifunctional linker molecules. A heparin density up to 0.86 microg cm(-2) on a dense PSu film was achieved. The modified PSu films were characterized by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The hydrophilicity of the PSu film was improved greatly by covalent immobilization of heparin. The water contact angle of PSu film was decreased from 86.6 + or - 3.7 degrees to 50.5 + or - 3.2 degrees after binding of 0.36 microg cm(-2) heparin. An enzyme-linked immunosorbent assay was used to measure the binding of LDL on plain and modified PSu films. It was found that the heparin-modified PSu film could selectively recognize LDL from binary protein solutions. Furthermore, it was possible to desorb LDL from heparinized PSu, but not from plain PSu, with heparin, sodium chloride or urea solution, which indicates a selective but reversible binding of LDL to heparin. The results suggest that heparin-modified PSu membranes are promising for application in simultaneous hemodialysis and LDL apheresis therapy.

Pediatric triglycerides predict cardiovascular disease events in the fourth to fifth decade of life

To assess relationships between pediatric lipids and subsequent cardiovascular disease (CVD) in the fourth to fifth decades, we conducted 22- to 31-year follow-up studies (1998-2003) in former schoolchildren first studied in 1973-1976. The follow-up included 53% of eligible former subjects. We compared pediatric and adult body mass (in kilograms per square meter) and lipids in 19 cases with at least 1 CVD event and in 789 CVD event-free subjects. Mean +/- SD age was 12.3 +/- 3.3 years at entry and 38.5 +/- 3.8 years at follow-up. Mean age at the first CVD event was 37.1 +/- 4.9 years. The major novel finding of our study was that childhood triglycerides (TG) were consistently and independently associated with young adult CVD. The distributions of both childhood and adult TG were shifted to higher levels in the cases than controls. Of the 19 cases, 7 (37%) had childhood TG greater than the pediatric 95th percentile (153 mg/dL); and 6 of these 7 had high TG (>/=150 mg/dL) at adult follow-up. Overall, 61% of cases had high TG as adults. After adjusting for age, sex, and race, by analysis of variance, cases had higher TG levels both in childhood and in young adulthood. A bootstrapping method and the Cox proportional hazard analysis were used to predict CVD in the cohort with explanatory variables sex; race; childhood body mass index, low-density lipoprotein, log high-density lipoprotein cholesterol, and log TG; and adult cigarette smoking and type 2 diabetes mellitus. Childhood TG level was a significant, independent explanatory variable for young adult CVD hazard (hazard ratio, 5.35; 95% confidence interval, 1.69-20.0 for each 1-unit increase in natural logarithm scale) along with adult type 2 diabetes mellitus (hazard ratio, 19.4; 95% confidence interval, 4.24-114.2). Pediatric hypertriglyceridemia appears to be a significant, independent, potentially reversible correlate of young adult CVD.

Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.