Design of Smart Aggregates: Toward Rapid Clinical Diagnosis of Hyperlipidemia in Human Blood

Molecular aggregates with environmental responsive properties are desired for their wide practical applications such as bioprobes. Here, a series of smart near-infrared (NIR) luminogens for hyperlipidemia (HLP) diagnosis is reported. The aggregates of these molecules exhibit a twisted intramolecular charge-transfer effect in aqueous media, but aggregation-induced emission in highly viscous media due to the restriction of the intramolecular motion. These aggregates, which can autonomously respond to different environments via switching the aggregation state without changing their chemical structures are described, as "smart aggregates". Intriguingly, these luminogens demonstrate NIR-II and NIR-III luminescence with ultralarge Stokes shifts (>950 nm). Both in vitro detection and in vivo imaging of HLP can be realized in a mouse model. Linear relationships exist between the emission intensity and multiple pathological parameters in blood samples of HLP patients. Thus, the design of smart aggregate facilitates rapid and accurate detection of HLP and provides a promising attempt in aggregate science.

Quantifying Atherogenic Lipoproteins: Current and Future Challenges in the Era of Personalized Medicine and Very Low Concentrations of LDL Cholesterol. A Consensus Statement from EAS and EFLM

BACKGROUND

The European Atherosclerosis Society-European Federation of Clinical Chemistry and Laboratory Medicine Consensus Panel aims to provide recommendations to optimize atherogenic lipoprotein quantification for cardiovascular risk management.

CONTENT

We critically examined LDL cholesterol, non-HDL cholesterol, apolipoprotein B (apoB), and LDL particle number assays based on key criteria for medical application of biomarkers. (a) Analytical performance: Discordant LDL cholesterol quantification occurs when LDL cholesterol is measured or calculated with different assays, especially in patients with hypertriglyceridemia >175 mg/dL (2 mmol/L) and low LDL cholesterol concentrations <70 mg/dL (1.8 mmol/L). Increased lipoprotein(a) should be excluded in patients not achieving LDL cholesterol goals with treatment. Non-HDL cholesterol includes the atherogenic risk component of remnant cholesterol and can be calculated in a standard nonfasting lipid panel without additional expense. ApoB more accurately reflects LDL particle number. (b) Clinical performance: LDL cholesterol, non-HDL cholesterol, and apoB are comparable predictors of cardiovascular events in prospective population studies and clinical trials; however, discordance analysis of the markers improves risk prediction by adding remnant cholesterol (included in non-HDL cholesterol) and LDL particle number (with apoB) risk components to LDL cholesterol testing. (c) Clinical and cost-effectiveness: There is no consistent evidence yet that non-HDL cholesterol-, apoB-, or LDL particle-targeted treatment reduces the number of cardiovascular events and healthcare-related costs than treatment targeted to LDL cholesterol.

SUMMARY

Follow-up of pre- and on-treatment (measured or calculated) LDL cholesterol concentration in a patient should ideally be performed with the same documented test method. Non-HDL cholesterol (or apoB) should be the secondary treatment target in patients with mild to moderate hypertriglyceridemia, in whom LDL cholesterol measurement or calculation is less accurate and often less predictive of cardiovascular risk. Laboratories should report non-HDL cholesterol in all standard lipid panels.

When and how to measure lipids and their role in CHD risk prediction

Accurate lipid and lipoprotein measurements, control of pre-analytical factors and consideration of biological variability are required for the reliable assessment of coronary heart disease (CHD) risk and the management of dyslipidaemia. Inclusion of high density lipoprotein-cholesterol, in addition to total cholesterol, in risk calculations is preferred to attain good sensitivity and specificity. Although the strong and independent association of triglyceride with CHD has been confirmed, its large biological variation limits its utility as a risk factor or primary treatment target. A fasting profile including triglyceride is essential however for consideration of genetic and secondary causes of dyslipidaemia and decisions on therapeutic intervention.

Association of apolipoprotein B and incidence of metabolic syndrome in Korean men: a 5-years' follow-up study

BACKGROUND AND OBJECTIVE

There have been reports for the association between elevated serum apolipoprotein B (ApoB) and several cardiometabolic disorders. However, it remains unclear whether serum ApoB level predicts the development of metabolic syndrome (MetS). Accordingly, we carried out a prospective study to evaluate the longitudinal effects of baseline serum ApoB levels on the development of MetS.

PATIENTS AND METHODS

A cohort of 25,193 healthy Korean men without MetS had been followed up prospectively. Baseline serum ApoB levels were categorized to following quintiles (quintile 1-5: <76.4, 76.4-88.4, 88.4-99.5, 99.5-113.0, ≥113.0). We evaluated the differences in the incidence of MetS according to quintiles of serum ApoB levels. Cox proportional hazards models were used to calculate the adjusted hazard ratios (HRs) for MetS.

RESULTS

During follow-up, 5407 (21.5%) cases developed MetS between 2006 and 2010. Incidence of MetS increased according to quintiles of serum ApoB levels [quintile 1-5: 9.1%, 16.4%, 22.1%, 27.3%, 36.4%, respectively (P for trend <0.001)]. Even after adjusting for various covariates including non-HDL-cholesterol, the hazard ratios (95% CI) for MetS increased in proportion to the quintiles of serum ApoB levels, compared to quintile 1 [quintile 2-5: 1.64 (1.43-1.89), 1.98 (1.71-2.31), 2.32 (1.96-2.75) and 2.92 (2.37-3.60), respectively (P for trend <0.001)]. These associations were apparent still in the clinically relevant subgroup analyses.

CONCLUSIONS

Serum ApoB levels predict MetS, independent of baseline confounding variables including non-HDL-cholesterol.

Assessing the clinical utility of biomarkers in medicine

Biomarkers in medicine have gained immense scientific and clinical interest in recent years. Biomarkers are potentially useful in the contexts of primary, secondary and tertiary prevention. Some of the characteristics of an ideal biomarker include that they are safe and easy to measure, are associated with acceptable costs (including those of the follow-up tests), and there is scientific evidence to suggest that biomarker use/modification influences disease outcomes. Additionally, variation in biomarker levels with gender and ethnicity should be elucidated, and the biomarker should have 'good performance characteristics' (i.e., sensitivity, specificity, positive- and negative-predictive values and positive- and negative-likelihood ratios). Risk prediction scores can combine information from several different biomarkers in order to estimate an individual's risk of developing an outcome, such as disease or death. Three commonly employed methods to test if a biomarker will add to traditional risk prediction models are model discrimination, model calibration and risk reclassification. 'Multimarker' strategies serve to integrate information from multiple biomarkers into risk prediction but may be limited by the presence of highly correlated biomarkers, economic costs and selection bias of biomarker candidates in a particular study sample. In the future, integration of biomarkers identified using emerging technologies from the 'omics fields (including genomics, proteomics, metabolomics, lipomics, ribomics and pharmacogenomics) may be useful for the 'personalization' of treatment/disease prevention.

Antisense therapy and emerging applications for the management of dyslipidemia

BACKGROUND

Because a significant percentage of patients who require high-dose statin therapy for dyslipidemia experience treatment-related muscle symptoms and an inconsistent clinical response, alternative or adjunctive approaches to the management of dyslipidemia are needed. One alternative approach, antisense therapy, may offer an effective and well-tolerated option for patients not satisfactorily responsive to or intolerant to standard pharmacologic dyslipidemia therapies.

OBJECTIVE

This review provides an overview of antisense technology and its potential role in the management of dyslipidemia.

METHODS

Source material was obtained primarily from the published literature identified through a search of the PubMed database.

RESULTS

Antisense technology is an evolving approach to therapy that has gone through a series of refinements to enhance molecular stability, potency, and tolerability. Mipomersen is an antisense molecule capable of producing clinically meaningful reductions in low-density lipoprotein cholesterol in patients with severe familial hypercholesterolemia. Further long-term clinical studies are required to more clearly quantify its impact on risk for cardiovascular events and establish whether it increases risk for hepatosteatosis.

CONCLUSION

Antisense therapy represents a potentially effective and well-tolerated emerging treatment modality for numerous diseases. In the treatment of hypercholesterolemia, the antisense therapy mipomersen may provide a possible treatment option for patients with treatment-resistant dyslipidemia.

Apolipoprotein B is highly associated with the risk of coronary heart disease as estimated by the Framingham risk score in healthy Korean men

The aim of this study was to examine the association between serum apolipoprotein B (apoB) and the risk of coronary heart disease (CHD) using Framingham risk score (FRS) in healthy Korean men. A total of 13,523 men without medication history of diabetes and hypertension were enrolled in this study. The FRS is based on six coronary risk factors. FRS ≥ 10% was defined as more-than-a-moderate risk group and FRS ≥ 20% as high risk group, respectively. The logistic regression analyses were conducted. When quartile 1 (Q1) set as a reference, in unadjusted analyses, the Q2, Q3, Q4 of apoB level had increased odds ratio (OR) for the risk of CHD in both more-than-a-moderate risk and high risk group, respectively. After adjusting for confounding variables, multivariable-adjusted logistic regression analyses showed a strong relationship between the quartiles of apoB level and more-than-a-moderate risk and high risk group, respectively. These associations were attenuated, but still remained statistically significant. ApoB is found to be independently related to the risk of CHD using FRS in healthy Korean men, and the link between apoB and the risk of CHD is dose-dependent.

Lipoprotein(a) Is the Best Single Marker in Assessing Unstable Angina Pectoris

This study evaluated whether statin therapy changed a diagnostic validity of lipid and inflammatory markers in ischemic heart disease (IHD) patients. Levels of lipids, lipoproteins, apolipoproteins, inflammatory markers, and atherogenic indexes were determined in 49 apparently healthy men and women, 82 patients having stable angina pectoris (SAP), 80 patients with unstable angina (USAP), and 106 patients with acute ST-elevation myocardial infarction (STEMI) treated or not treated with statins. Diagnostic accuracy of markers was determined by ROC curve analysis. Significantly lower apoA-I in all statin-treated groups and significantly higher apoB in statin-treated STEMI group compared to non-statin-treated groups were observed. CRP showed the best ROC characteristics in the assessment of STEMI patients. Lp(a) is better in the evaluation of SAP and USAP patients, considering that Lp(a) showed the highest area under the curve (AUC). Regarding atherogenic indexes, the highest AUC in SAP group was obtained for TG/apoB and in USAP and STEMI patients for TG/HDL-c. Statins lowered total cholesterol, LDL-c, and TG but fail to normalize apoA-I in patients with IHD.

Apolipoprotein B is a better marker than non-HDL-cholesterol for the metabolic syndrome in Koreans

Apolipoprotein B (apoB) concentration reflects the number of atherogenic particles and is closely associated with atherosclerosis. Non-HDL-cholesterol (non-HDL-C) has been considered a therapeutic target for patients with hypertriglyceridemia. We compared the predictive values of apoB and non-HDL-C for the metabolic syndrome (MetS) in 3335 Korean adults (mean age, 45.2 years) who participated consecutively in a health examination in a university hospital. Anthropometry, blood pressure, fasting glucose, lipid profiles and apoB were measured. MetS, as defined by a modification of the NCEP-ATP III criteria, was present in 22.1% of men and 16.1% of women. Among the components of the MetS, triglycerides showed the strongest correlation with apoB (r=0.393, P<0.001 in men, and r=0.326, P<0.001 in women) and non-HDL-C (r=0.376, P<0.001 in men, and r=0.349, P<0.001 in women). When apoB and non-HDL-C were mutually adjusted, the ORs for the MetS of non-HDL-C were not significant. As a function of the quartile of apoB levels, the ORs for the MetS were 2.04 (1.26-3.30), 3.54 (2.11-5.93), and 5.38 (3.16-9.17) in men (P for trend <0.001) and 3.75 (1.42-9.87), 5.55 (2.09-14.69), and 13.41 (5.02-35.79) in women (P for trend <0.001), respectively. These findings indicate that apoB is a better marker than non-HDL-C for identifying the MetS among Koreans.

Tesaglitazar, a dual peroxisome proliferator-activated receptor alpha/gamma agonist, improves apolipoprotein levels in non-diabetic subjects with insulin resistance

AIM

To determine the effects of the peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist tesaglitazar on serum levels of apolipoprotein (apo) A-I, apoB, and apoCIII in non-diabetic insulin-resistant subjects.

METHODS

This randomized, double-blind, multicentre, placebo-controlled trial examined the effect of tesaglitazar (0.1, 0.25, 0.5, and 1mg) once daily for 12 weeks on apolipoprotein levels in 390 abdominally obese subjects with hypertriglyceridaemia.

RESULTS

Tesaglitazar dose-dependently increased serum concentrations of apoA-I (p<0.009) and decreased concentrations of apoB (p<0.0001), the apoB/apoA-I ratio (p<0.0001), and apoCIII (p<0.0001). Similar improvements were observed in all subgroups of subjects, where individuals were grouped according to age, gender, baseline body mass index, serum triglycerides and high-density lipoprotein cholesterol levels. Low-density lipoprotein particle concentrations were also dose-dependently reduced by tesaglitazar (p<0.0001).

CONCLUSION

Although tesaglitazar is no longer in clinical development, these data indicate that dual PPARalpha/gamma agonism may be a useful pharmacological approach to improve the atherogenic dyslipidaemia associated with insulin resistance.

Comparison of assessment techniques: plasma lipid and lipoproteins related to the metabolic syndrome

Background

The purpose of this investigation was to determine the influence of analytical method on reported concentrations of plasma lipids and lipoproteins, and to determine if there are clinical implications of any potential differences on identification of the metabolic syndrome dyslipidemia, CVD risk stratification and classification of LDL subclass phenotype.

Results

Plasma triglyceride (TG) concentrations were 1.09 ± 0.06 and 1.17 ± 0.06 mmol/L and plasma high density lipoprotein cholesterol (HDL-C) concentrations were 1.09 ± 0.03 vs 1.19 ± 0.03 mmol/L (both p < 0.05) from 113 duplicate samples sent to two laboratories utilizing different lipid and lipoprotein analytical methods (LABS 1 and 2, respectively). Plasma total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations were also significantly different between laboratories. Spearman rho correlations indicate excellent agreement of TG and HDL-C determined by the two laboratories (r = 0.96, TG; r = 0.91, HDL-C, both p < 0.001). Eleven vs. 14 individuals met the TG criteria and 70 vs. 48 met HDL-C metabolic syndrome criteria with LAB 1 and 2, respectively. Apoprotein B concentration (LAB 1) and LDL particle number (LAB 2) were highly correlated. (r = 0.92, P < 0.01). LAB 2 characterized more individuals as LDL pattern B phenotype, as compared to LAB 1 (30 vs. 14%, P < 0.05).

Conclusion

Different plasma lipid and lipoprotein analytical techniques yield results which are highly correlated, yet significantly different, which suggests a consistent measurement difference. This difference has clinical implications, in that the proportion of individuals identified as meeting the metabolic syndrome dyslipidemia criteria, "at risk" based upon apo B or LDL particle number, and the LDL pattern B phenotype will differ based upon choice of analytical method.

Lipid abnormalities associated with urinary albumin excretion rate in Taiwanese type 2 diabetic patients

BACKGROUND

The purpose of this study was to examine the lipid abnormalities associated with urinary albumin excretion rate (UAER) in type 2 diabetic patients.

METHODS

A total of 275 (122 men and 153 women; aged 60.6 +/- 11.1 years) patients were selected with stringent criteria to prevent confounders. Normoalbuminuria (N= 152) and albuminuria (N= 123) were defined as urinary albumin-to-creatinine ratio (ACR) of <30 and > or =30 microg/mg, respectively. Total cholesterol, triglycerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and apolipoproteins A1 (ApoA1) and B (ApoB) were measured and non-HDL cholesterol calculated. The subjects were divided into four phenotypes based on triglycerides (<1.5 or > or =1.5 mmol/L) and ApoB (<1.2 or > or =1.2 g/L).

RESULTS

Total cholesterol, ApoB, and non-HDL cholesterol were significantly (P < 0.05) higher in patients with albuminuria. For quartiles of the lipid parameters, prevalences of albuminuria showed significant association with ApoB and non-HDL cholesterol (P trend <0.05). After adjusting for age, systolic blood pressure and hemoglobin A(1c) (HbA(1c)) correlation coefficients between the natural logarithm (ln) ACR and lipid parameters, odds ratios for albuminuria, and standardized regression coefficients for ln ACR, were significant for total cholesterol, ApoB and non-HDL cholesterol in all subjects and in men, but only ApoB was significant in women. For patients with normoalbuminuria, frequencies of normotriglycerides/normo-ApoB, hypertriglycerides/normo-ApoB, normotriglycerides/hyper-ApoB, and hypertriglycerides/hyper-ApoB were 44.7%, 28.9%, 10.5%, and 15.8%, respectively; and were 30.1%, 19.5%, 15.4%, and 35.0% for patients with albuminuria (P < 0.001). The respective adjusted odds ratio for albuminuria for the four phenotypes was 1.00, 1.04 (0.54 to 2.00), 2.25 (1.02 to 5.00), and 3.38 (1.75 to 6.53).

CONCLUSION

Increased UAER is associated with ApoB-containing lipoproteins and the phenotype of hypertriglycerides/hyper-ApoB is associated with the highest risk of albuminuria. The surrogate marker of non-HDL cholesterol for ApoB is more applicable to the diabetic men.

Comparison of apolipoprotein B and plasma lipids as targets for lipid lowering treatment

OBJECTIVE

To assess the discrepancies between LDL-cholesterol and apo B targets in patients at risk for vascular disease; namely, those with diabetes or hypertriglyceridemia and those with triglycerides <1.7 mmol/L and normal glucose homeostasis.

METHODS

Lipid clinic patients were divided into two groups: Group 1 consisted of 182 patients whose triglyceride levels were >1.7 mmol/L or who had impaired fasting glucose or type 2 diabetes. In Group 2, there were 42 patients with triglycerides <1.7 mmol/L and normal glucose homeostasis. LDL-cholesterol and apo B were estimated during lipid clinic visits with patients on appropriate lipid lowering therapy.

RESULTS

46% of the patients in Group 1 who reached the high risk LDL-cholesterol target of <2.5 mmol/L did not reach apo B target of <0.9 g/L, while in Group 2, only 19% of those who reached the LDL-cholesterol target had apo B >0.9 g/L.

CONCLUSION

Our findings demonstrate that a large percentage of patients with hypertriglyceridemia or impaired glucose tolerance, treated with lipid lowering agents, reach the LDL-cholesterol but not the apo B treatment targets.

Apolipoprotein B and apolipoprotein A-I: risk indicators of coronary heart disease and targets for lipid-modifying therapy

Although LDL cholesterol (LDL-C) is associated with an increased risk of coronary heart disease, other lipoproteins and their constituents, apolipoproteins, may play an important role in atherosclerosis. Elevated levels of apolipoprotein (apo) B, a constituent of atherogenic lipoproteins, and reduced levels of apo A-I, a component of anti-atherogenic HDL, are associated with increased cardiac events. Apo B, apo A-I and the apo B/apo A-I ratio have been reported as better predictors of cardiovascular events than LDL-C and they even retain their predictive power in patients receiving lipid-modifying therapy. Measurement of these apolipoproteins could improve cardiovascular risk prediction.

Dyslipidaemia

The lowering of serum cholesterol is increasingly recognised as essential in the prevention of coronary heart disease and other atherosclerotic disease. The success of statin trials and the need to deploy these drugs effectively in the population has led increasingly to the identification of many people whose serum cholesterol, triglycerides, and HDL-cholesterol require clinical assessment, and frequently treatment. Lipid disorders are mainly straightforward, but some are complex or resistant to simple treatment strategies. I have reviewed the clinical manifestations of disordered lipid metabolism (dyslipidaemia) and its management.

Non-HDL cholesterol and apolipoprotein B in the dyslipidemic classification of type 2 diabetic patients

OBJECTIVE

To compare non-HDL cholesterol (HDLc) and apolipoprotein B (apoB) in the identification of nonconventional high-risk dyslipidemic phenotypes in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Total cholesterol and triglycerides, HDLc, LDL cholesterol, non-HDLc, apolipoprotein B (apoB), and LDL size were determined in 122 type 2 diabetic patients (68% male, aged 59.6 +/- 9.7 years, and HbA(1c) 7.5% [range 5.2-16.0]). They were then classified as normo- and hypertriglyceridemic if their triglyceride concentrations were below/above 2.25 mmol/l, as normo/hyper-non-HDLc if non-HDLc concentrations were below/above 4.13 mmol/l, and as normo- and hyperapoB if apoB concentrations were below/above 0.97 g/l. Both classifications were compared (concordance assessed with the kappa index), and low HDLc and LDL phenotype B were identified in each category.

RESULTS

A total of 26 patients were hypertriglyceridemic and 96 were normotriglyceridemic. All hypertriglyceridemic subjects had increased non-HDLc, whereas 24 had increased apoB (kappa= 0.95). In the normotriglyceridemic group, 44 had increased non-HDLc, 68 had increased apoB, and 25 of the 52 patients with normal non-HDLc had increased apoB (kappa= 0.587). Low HDLc and LDL phenotype B were similarly distributed into the equivalent categories.

CONCLUSIONS

Non-HDLc and apoB are equivalent risk markers in hypertriglyceridemic patients, but apoB identifies additional patients with high-risk dyslipidemic phenotypes in normotriglyceridemic type 2 diabetic patients.

Small, dense LDL and elevated apolipoprotein B are the common characteristics for the three major lipid phenotypes of familial combined hyperlipidemia

OBJECTIVE

Familial combined hyperlipidemia (FCHL) is associated with variable lipid and lipoprotein phenotypes arbitrarily defined as type IIa, IIb, and IV based on plasma total cholesterol and triglyceride levels. This study sought to characterize consistent lipoprotein and lipid abnormalities across the 3 lipoprotein phenotypes in 62 patients with documented FCHL (IIa [n=14], IIb [n=19], and IV [n=29]) and 44 healthy individuals.

METHODS AND RESULTS

The lipoprotein cholesterol distribution was determined over 38 fractions obtained by density gradient ultracentrifugation. As expected, FCHL patients with hypertriglyceridemia (IIb and IV) had higher cholesterol levels in VLDL than IIa, whereas IIa showed higher cholesterol in the big, buoyant LDL and in HDL. LDL cholesterol was higher in IIb than IV; most of the increase in LDL cholesterol was associated with big, buoyant LDL rather than small, dense LDL (sdLDL). The differences in lipoproteins between phenotypes were attributable to changes in VLDL and big, buoyant LDL levels. Comparison of the FCHL patients with healthy individuals showed a significant elevation in plasma apolipoprotein B levels and sdLDL in all 3 FCHL phenotypes.

CONCLUSIONS

Although triglyceride and cholesterol levels are variable by lipoprotein phenotype, sdLDL and elevated plasma apolipoprotein B levels are consistent characteristics of FCHL shared by the 3 different lipoprotein phenotypes.