Relation between insulin resistance and fast-migrating LDL subfraction as characterized by capillary isotachophoresis

The Reciprocal Relationship between LDL Metabolism and Type 2 Diabetes Mellitus

Type 2 diabetes mellitus and insulin resistance feature substantial modifications of the lipoprotein profile, including a higher proportion of smaller and denser low-density lipoprotein (LDL) particles. In addition, qualitative changes occur in the composition and structure of LDL, including changes in electrophoretic mobility, enrichment of LDL with triglycerides and ceramides, prolonged retention of modified LDL in plasma, increased uptake by macrophages, and the formation of foam cells. These modifications affect LDL functions and favor an increased risk of cardiovascular disease in diabetic individuals. In this review, we discuss the main findings regarding the structural and functional changes in LDL particles in diabetes pathophysiology and therapeutic strategies targeting LDL in patients with diabetes.

Electronegative LDL: An Active Player in Atherogenesis or a By- Product of Atherosclerosis?

Low-density lipoproteins (LDLs) are the major plasma carriers of cholesterol. However, LDL particles must undergo various molecular modifications to promote the development of atherosclerotic lesions. Modified LDL can be generated by different mechanisms, but as a common trait, show an increased electronegative charge of the LDL particle. A subfraction of LDL with increased electronegative charge (LDL(-)), which can be isolated from blood, exhibits several pro-atherogenic characteristics. LDL(-) is heterogeneous, due to its multiple origins but is strongly related to the development of atherosclerosis. Nevertheless, the implication of LDL(-) in a broad array of pathologic conditions is complex and in some cases anti-atherogenic LDL(-) properties have been reported. In fact, several molecular modifications generating LDL(-) have been widely studied, but it remains unknown as to whether these different mechanisms are specific or common to different pathological disorders. In this review, we attempt to address these issues examining the most recent findings on the biology of LDL(-) and discussing the relationship between this LDL subfraction and the development of different diseases with increased cardiovascular risk. Finally, the review highlights the importance of minor apolipoproteins associated with LDL(-) which would play a crucial role in the different properties displayed by these modified LDL particles.

LDL electronegativity index: a potential novel index for predicting cardiovascular disease

High cardiovascular risk conditions are frequently associated with altered plasma lipoprotein profile, such as elevated low-density lipoprotein (LDL) and LDL cholesterol and decreased high-density lipoprotein. There is, however, accumulating evidence that specific subclasses of LDL may play an important role in cardiovascular disease development, and their relative concentration can be regarded as a more relevant risk factor. LDL particles undergo multiple modifications in plasma that can lead to the increase of their negative charge. The resulting electronegative LDL [LDL(–)] subfraction has been demonstrated to be especially atherogenic, and became a subject of numerous recent studies. In this review, we discuss the physicochemical properties of LDL(–), methods of its detection, atherogenic activity, and relevance of the LDL electronegativity index as a potential independent predictor of cardiovascular risk.

Antiatherogenic effects of newly developed apolipoprotein A-I mimetic peptide/phospholipid complexes against aortic plaque burden in Watanabe-heritable hyperlipidemic rabbits

This study analyzed the antiatherogenic effects of newly developed apolipoprotein A-I (ApoA-I) mimetic peptide/phospholipid complexes (ETC-642) against the aortic plaque burden in vivo. We used human macrophage cells to analyze cholesterol efflux by ETC-642. Watanabe-heritable hyperlipidemic (WHHL) rabbits were divided into 3 groups: low- (15mg/kg) and high-dose ETC-642 (50mg/kg), and placebo. The test material was injected twice/week for 12 weeks. The aortic plaque burden was assessed by intravascular ultrasound (IVUS) at 0 and 12 weeks. Plasma lipid profiles were analyzed by capillary isotachophoresis every 4 weeks. ETC-642 had an effect on cholesterol efflux comparable to that of conventional rHDL. In WHHL rabbits, high-dose ETC-642 inhibited the progression of aortic atherosclerosis compared to placebo. There was no change in the percentage of plaque volume (%PV) in the high-dose group between before (30.9%) and after infusion (28.6%), whereas there was a significant increase in the control group from 27.8% to 37.9%. ETC-642 significantly reduced charge-modified low-density lipoprotein (LDL) by converting more negative-charged modified LDL to less negative-charged LDL, and reduced small dense (sd) LDL by converting it into large, buoyant (lb) LDL. Changes in the %PV were positively correlated with changes in negative-charged modified LDL (r=0.61, p<0.01) and sdLDL (r=0.59, p<0.01), and negatively correlated with changes in less negative-charged LDL (r=-0.43, p<0.01) and lbLDL (r=-0.57, p<0.01). In conclusion, the ETC-642-induced remodeling of sdLDL to large and lbLDL and the enhancement of cholesterol efflux may prevent progression of the aortic plaque burden. HDL-based therapy may be useful for preventing the progression of plaque volume.

Randomized head-to-head comparison of pitavastatin, atorvastatin, and rosuvastatin for safety and efficacy (quantity and quality of LDL): the PATROL trial

BACKGROUND

Atorvastatin, rosuvastatin and pitavastatin are available for intensive, aggressive low-density lipoprotein cholesterol (LDL-C)-lowering therapy in clinical practice. The objective of the Randomized Head-to-Head Comparison of Pitavastatin, Atorvastatin, and Rosuvastatin for Safety and Efficacy (Quantity and Quality of LDL) (PATROL) Trial was to compare the safety and efficacy of atorvastatin, rosuvastatin and pitavastatin head to head in patients with hypercholesterolemia. This is the first prospective randomized multi-center trial to compare these strong statins (UMIN Registration No: 000000586).

METHODS AND RESULTS

Patients with risk factors for coronary artery disease and elevated LDL-C levels were randomized to receive atorvastatin (10mg/day), rosuvastatin (2.5mg/day), or pitavastatin (2mg/day) for 16 weeks. Safety was assessed in terms of adverse event rates, including abnormal clinical laboratory variables related to liver and kidney function and skeletal muscle. Efficacy was assessed by the changes in the levels and patterns of lipoproteins. Three hundred and two patients (from 51 centers) were enrolled, and these 3 strong statins equally reduced LDL-C and LDL particles, as well as fast-migrating LDL (modified LDL) by 40-45%. Newly developed pitavastatin was non-inferior to the other 2 statins in lowering LDL-C. There were no differences in the rate of adverse drug reactions among the 3 groups, but HbA(1c) was increased while uric acid was decreased in the atorvastatin and rosuvastatin groups.

CONCLUSIONS

The safety and efficacy of these 3 strong statins are equal. It is suggested that the use of these 3 statins be completely dependent on physician discretion based on patient background.

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.

Effects of rosuvastatin on electronegative LDL as characterized by capillary isotachophoresis: the ROSARY Study

Electronegative LDL, a charge-modified LDL (cm-LDL) subfraction that is more negatively charged than normal LDL, has been shown to be inflammatory. We previously showed that pravastatin and simvastatin reduced the electronegative LDL subfraction, fast-migrating LDL (fLDL), as analyzed by capillary isotachophoresis (cITP). The present study examined the effects of rosuvastatin on the more electronegative LDL subfraction, very-fast-migrating LDL (vfLDL), and small, dense charge-modified LDL (sd-cm-LDL) subfractions. Patients with hypercholesterolemia or those who were being treated with statins (n = 81) were treated with or switched to 2.5 mg/d rosuvastatin for 3 months. Rosuvastatin treatment effectively reduced cITP cm-LDL subfractions of LDL (vfLDL and fLDL) or sdLDL (sd-vfLDL and sd-fLDL), which were closely related to each other but were different from the normal subfraction of LDL [slow-migrating LDL (sLDL)] or sdLDL (sd-sLDL) in their relation to the levels of remnant-like particle cholesterol (RLP-C), apolipoprotein (apo) C-II, and apoE. The percent changes in cm-LDL or sd-cm-LDL caused by rosuvastatin were correlated with those in the particle concentrations of LDL or sdLDL measured as LDL-apoB or sdLDL-apoB and the levels of HDL-C, RLP-C, apoC-II, and apoE. In conclusion, rosuvastatin effectively reduced both the vfLDL subfraction and sd-cm-LDL subfractions as analyzed by cITP.

Reduction of charge-modified LDL by statin therapy in patients with CHD or CHD risk factors and elevated LDL-C levels: the SPECIAL Study

Various forms of atherogenic modified low-density lipoprotein (LDL) including oxidized LDL and small, dense LDL have increased negative charge as compared to normal LDL. Charge-modified LDL (electronegative LDL) and normal LDL subfractions in plasma are analyzed by capillary isotachophoresis (cITP) as fast-migrating LDL (fLDL) and slow-migrating LDL (sLDL). We examined the effects of pravastatin and simvastatin on charge-based LDL subfractions as determined by cITP in patients with hypercholesterolemia. Patients (n=72) with CHD or CHD risk factors and elevated LDL cholesterol (LDL-C) levels were randomly assigned to receive pravastatin or simvastatin. After treatment with statins for 3 and 6 months, both cITP fLDL and sLDL were reduced (p<0.05) from the baseline, but the effects did not differ between treatment with pravastatin and simvastatin. At baseline and after treatment for 3 months, cITP sLDL was correlated with LDL-C, but fLDL was correlated with inflammatory markers, high-sensitive C-reactive protein and LDL-associated platelet-activating factor acetylhydrolase, and atherogenic lipoproteins, remnant-like particle cholesterol and small, dense LDL cholesterol. In conclusion, cITP fLDL was related to inflammatory markers and atherogenic lipoproteins and was reduced by treatment with statins. Charge-modified LDL subfraction could be a potential marker for atherosclerosis and a target for therapy.

Changes in lipid metabolism in postmenopausal Japanese women using hormone therapy evaluated by capillary isotachophoresis: a pilot study

OBJECTIVE

The aim of this study was to clarify the changes in lipid metabolism in postmenopausal Japanese women during continuous combined hormone therapy (HT) in detail by using capillary isotachophoresis (cITP).

DESIGN

Twenty-three postmenopausal Japanese women with climacteric symptoms were recruited. Blood samples were collected from all participants before HT and after 3 and 6 months of HT, and changes in total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and apolipoprotein (apo) A-I, apoB, and lipoprotein(a) were assessed. The same blood samples were analyzed for charge-based lipoprotein subfractions using cITP.

RESULTS

Total cholesterol (-8.5%), LDL-cholesterol (-16.2%), and lipoprotein(a) (-25.5%) decreased and apoA-I (9.5%) increased significantly from the baseline level at 6 months after starting continuous combined HT. HDL-cholesterol increased nonsignificantly (+2.4%). cITP revealed that the fast HDL subfraction (+24.7%), which contains apoA-I and may be antiatherogenic, significantly increased. Conversely, the fast LDL subfraction (+14.4%), which may possess atherogenic potential, increased during HT.

CONCLUSIONS

The changes in lipid metabolism in postmenopausal Japanese women receiving HT are inconclusive regarding atherogenicity, ie, it increased fast HDL and simultaneously increased fast LDL. cITP is useful for clarifying the changes in lipid metabolism during HT.

POPC/apoA-I discs as a potent lipoprotein modulator in Tangier disease

Tangier disease (TD) is a rare familial disorder with mutations in the ATP-binding cassette transporter A1 (ABCA1) gene. It results in extremely low levels of HDL cholesterol. Since TD is a genetic disorder, a therapeutic approach to TD has not been established. We report a typical case of TD with a homozygous novel point mutation in the ABCA1 gene by using genomic DNA sequencing. Primary monocyte-derived macrophages of blood from a patient with TD and normolipidemic subjects were compared for cholesterol efflux. The macrophages from the TD patient showed no apoA-I-mediated cholesterol efflux. In contrast, POPC/apoA-I discs were able to take up cholesterol from macrophages from both the TD and normolipidemic subject. Capillary isotachophoresis (cITP), which separates lipoprotein into subfractions according to electrophoretic mobility, was used to characterize plasma lipoprotein subfractions. Both slow-migrating HDL (sHDL) and slow-migrating LDL (sLDL; unmodified LDL) subfractions were extremely low in the patient with TD. After incubation of plasma from the TD patient with POPC/apoA-I discs, sHDL and sLDL subfractions rapidly appeared. In conclusion, POPC/apoA-I discs not only have beneficial effects on cholesterol efflux, but also have potential as a lipoprotein modulator in patients with TD.

Effects of reconstituted HDL on charge-based LDL subfractions as characterized by capillary isotachophoresis

Modified LDL in human plasma including small, dense LDL (sdLDL) and oxidized LDL carries a more negative charge than unmodified LDL and is atherogenic. We examined the effects of apolipoprotein A-I (apoA-I)/POPC discs on charge-based LDL subfractions as determined by capillary isotachophoresis (cITP). Three normal healthy subjects and seven patients with metabolic disorders were included in the study. LDL in human plasma was separated into two major subfractions, fast- and slow-migrating LDL (fLDL and sLDL), by cITP. Normal LDL was characterized by low fLDL, and mildly oxidized LDL in vitro and mildly modified LDL in human plasma were characterized by increased fLDL. Moderately oxidized LDL in vitro and moderately modified LDL in a patient with hypertriglyceridemia and HDL deficiency were characterized by both increased fLDL and a new LDL subfraction with a faster mobility than fLDL [very-fast-migrating LDL as determined by cITP (vfLDL)]. cITP LDL subfractions with faster electrophoretic mobility (fLDL vs. sLDL, vfLDL vs. fLDL) were associated with an increased content of sdLDL. Incubation of a plasma fraction with d>1.019 g/ml (depleted of triglyceride-rich lipoproteins) in the presence of apoA-I/POPC discs at 37 degrees C greatly decreased vfLDL and fLDL but increased sLDL. Incubation of whole plasma from patients with an altered distribution of cITP LDL subfractions in the presence of apoA-I/POPC discs also greatly decreased fLDL but increased sLDL. ApoA-I/POPC discs decreased the cITP fLDL level, the free cholesterol concentration, and platelet-activating factor acetylhydrolase activity in the sdLDL subclasses (d=1.040-1.063 g/ml) and increased the size of LDL. ApoA-I/POPC discs reduced charge-modified LDL in human plasma by remodeling cITP fLDL into sLDL subfractions.

Electronegative low-density lipoprotein subfraction from type 2 diabetic subjects is proatherogenic and unrelated to glycemic control

BACKGROUND

The physicochemical and biological characteristics of electronegative low-density lipoprotein (LDL) (LDL(-)) from type 2 diabetic patients (DM2), before and after insulin therapy, were studied.

METHODS

Total LDL was subfractionated in LDL(+) (native LDL) and LDL(-) by anion-exchange chromatography.

RESULTS

The proportion of LDL(-) was increased in plasma from DM2 patients compared to control subjects (13.8 +/- 4.6% versus 6.1 +/- 2.5, P < 0.05) and was not modified after glycemic optimization (14.0 +/- 5.9%). LDL(-) from DM2 patients presented similar differential characteristics versus LDL(+) than LDL(-) from controls; that is, decreased apoB and oxidizability, and increased triglyceride, nonesterified fatty acids (NEFA), apoE, apoC-III, platelet-activating factor (PAF) acetylhydrolase activity and aggregability. No difference in particle size, antioxidants, malondialdehyde (MDA), fructosamine or glycated low-density lipoprotein (gLDL) was observed between LDL subfractions. Concerning differences between LDL subfractions isolated from DM2 and from control subjects, the former showed increased MDA, fructosamine and gLDL proportion and decreased LDL size and antioxidant content. The only effect of glycemic optimization was a decrease in fructosamine and gLDL in LDL(+) from DM2 subjects. LDL(-) from DM2 patients presented low binding affinity to the low-density lipoprotein receptor (LDLr) in cultured fibroblasts compared to LDL(+) and two- to threefold increased ability to release interleukin-8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) in endothelial cells.

CONCLUSION

These results suggest that, although nonenzymatic glycosylation and oxidation are increased in type 2 diabetes, these features would not be directly involved in the generation of LDL(-). Moreover, LDL(-) properties suggest that the high proportion observed in plasma could promote accelerated atherosclerosis in DM2 patients through increased residence time in plasma and induction of inflammatory responses in artery wall cells.

Recent progress in capillary ITP

ITP has been attracting constant attention for many years due to its principal capability to concentrate trace analytes by several orders of magnitude. In the current capillary format, it is able to concentrate trace analytes diluted to several microliters of an original sample into concentrated zones having volumes in the range of picoliters. Due to this reason, ITP holds an important position in many current multistage and multidimensional separation schemes. This article links up previous reviews on the topic and summarizes the progress of analytical capillary ITP since 2002. Almost 100 papers are reviewed that include methodological novelties, instrumental aspects, and analytical applications. Papers using ITP and/or isotachophoretic principles as part of multistage and/or multidimensional separation schemes are also included.

Effect of levothyroxine on total lipid profiles as assessed by analytical capillary isotachophoresis in a patient with hypothyroidism

The patient was a 51-year-old Japanese female who had been diagnosed with hyperlipidemia. At the first medical examination, her serum levels of total cholesterol (TC) and triglyceride (TG) were 482 and 205 mg/dl, respectively. Since hyperlipidemia was not improved by pravastatin, atorvastatin or niceritrol, and since the levels of thyroid-stimulating hormone (TSH) and free T4 were 730 IU/ml and 0.3 ng/dl, respectively, the patient was diagnosed as secondary hyperlipidemia with hypothyroidism. A method for the charge isolation of lipoproteins using capillary isotachophoresis (cITP) is proposed as a clinical application because it allows us to quantitatively measure electronegative low-density lipoprotein cholesterol (LDL-C), a potent marker of coronary heart disease. After 5 months of treatment with levothyroxine, Serum TC and LDL-C levels drastically decreased without statin treatment and high-density lipoprotein cholesterol (HDL-C) increased. In the lipoprotein profiles as assessed by cITP after treatment with levothyroxin, all HDL-C subfractions were increased and fast-migrating LDL/electronegative LDL appeared to be greatly reduced after treatment, while the area under the non-modified LDL peak was increased. The cITP analysis was able to obtain more information about coronary risk factors and may be clinically useful for evaluating the effect of treatment with levothyroxine in patients with hypothyroidism and secondary hyperlipidemia.

Capillary isotachophoresis from the student point of view – images and the reality

A review of some fundamental aspects of ITP from the student point of view, imaginations of some basic facts and laws, use of ITP, and the recent trends are presented. The results of theoretical computations of ITP separation processes are added for comparison of imaginations with the exact mathematical description.

Effects of atorvastatin and apoA-I/phosphatidylcholine discs on triglyceride-rich lipoprotein subfractions as characterized by capillary isotachophoresis

BACKGROUND

The present study examined the effects of atorvastatin and the in vitro effect of apolipoprotein (apo) A-I/phosphatidylcholine (POPC) discs on charge-based triglyceride-rich lipoprotein (TRL) subfractions in a patient with type III hyperlipoproteinemia (HLP) and the apoE2/2 phenotype.

METHODS

Charge-based lipoprotein subfractions were characterized by capillary isotachophoresis (cITP). cITP analysis was performed using plasma that had been prestained with a lipophilic dye on a Beckman P/ACE MDQ system.

RESULTS

Treatment with atorvastatin for 4 weeks markedly decreased the slow (s)-migrating TRL subfraction and both fast- and slow-migrating low-density lipoprotein (LDL) subfractions, but did not affect the fast (f)-migrating TRL subfraction in this patient. ApoA-I/POPC discs consisted of two major charge-based subfractions that had the mobility of cITP fTRL and sTRL. Incubation of plasma from this patient in the presence of apoA-I/POPC discs caused not only a reduction in cITP fast- and intermediate-migrating HDL and an increase in cITP sHDL but also a reduction in fTRL and sTRL and an increase in sLDL.

CONCLUSION

Atorvastatin and apoA-I/POPC discs decreased cITP TRL subfractions in a complementary manner, suggesting that the combination of apoA-I/POPC discs and atorvastatin could be a promising therapeutic approach for hypertriglyceridemia.

ApoA-I/phosphatidylcholine discs remodels fast-migrating HDL into slow-migrating HDL as characterized by capillary isotachophoresis

OBJECTIVE

Capillary isotachophoresis (cITP) is a technique for characterizing plasma lipoprotein subfractions according to their electrophoretic charges. We used this technique to examine the mechanism by which apoA-I/phosphatidylcholine (POPC) discs increase pre-beta HDL.

METHODS AND RESULTS

The cITP analysis was performed using plasma prestained with a lipophilic dye on a Beckman P/ACE MDQ system. Plasma from a patient with lecithin:cholesterol acyltransferase (LCAT) deficiency who had increased apoE-containing HDL was used to characterize the charge distribution of apoA-I/POPC discs. cITP analysis of apoB- and E-depleted plasma of the patient in the presence of apoA-I/POPC discs indicated two major subfractions of apoA-I/POPC discs with mobilities of triglyceride-rich lipoproteins (fast and slow apoA-I). Incubation of whole plasma from a normolipidemic subject in the presence of apoA-I/POPC discs caused a reduction in cITP fast (f)- and intermediate (i)-migrating HDL, and fast and slow apoA-I, and an increase in slow (s)-migrating HDL. The changes in cITP lipoprotein subfractions were not affected by the inhibition of LCAT activity. ApoA-I/POPC discs increased the fractional esterification rate of cholesterol in apoB-depleted plasma.

CONCLUSION

ApoA-I/POPC discs remodeled cITP fHDL and iHDL to sHDL independent of LCAT activity.

Association between fast-migrating low-density lipoprotein subfraction as characterized by capillary isotachophoresis and intima-media thickness of carotid artery

BACKGROUND

A mildly modified LDL subfraction that is characterized by an increased negative charge exists in plasma. This electronegative LDL separated by ion-exchange chromatography has been shown to be inflammatory and its proportion is increased in patients with hyperlipidemia and diabetes mellitus. The present study examined the association between the level of fast (f)-migrating LDL subfraction characterized by capillary isotachophoresis (cITP) and carotid-artery intima-media thickness (CA-IMT).

METHODS AND RESULTS

This study included 469 subjects who underwent a physical examination. CA-IMT was determined by high-resolution B-model ultrasonoraphy. Levels of charge-based LDL subfractions were measured by cITP on a Beckman P/ACE MDQ system. An increased serum LDL-C level and cITP fLDL level were associated with increased CA-IMT after adjusting for age. The extent of the associations between cITP fLDL and CA-IMT and between LDL-C and CA-IMT were similar as assessed by a receiver-operating characteristic curve analysis. LDL-C, triglyceride, and remnant-like particle cholesterol levels were independently correlated with cITP fLDL, and the LDL-C level had the strongest correlation with cITP fLDL. The association between the cITP fLDL level and CA-IMT was significant in the high LDL-C stratum but not in the low stratum, indicating that it is modified by the LDL-C level. The high-LDL-C-high-fLDL group had the highest relative risk for a high CA-IMT among the groups with each combination of LDL-C and cITP fLDL level.

CONCLUSION

The cITP fLDL level was associated with CA-IMT and its combination with the LDL-C level is a stronger indicator for a high CA-IMT.

Relation between charge-based apolipoprotein B-containing lipoprotein subfractions and remnant-like particle cholesterol levels

OBJECTIVE

Both mildly modified LDL subfraction that carries a more-negative electric charge and remnant-like particles (RLP) are closely related to triglyceride (TG) levels. We examined the relation between the RLP-cholesterol (C) level and charge-based apolipoprotein (apo) B-containing lipoprotein subfractions as determined by capillary isotachophoresis (cITP) in patients with hypercholesterolemia.

METHODS AND RESULTS

cITP apo B lipoprotein subfractions were identified by analyzing plasma depleted of the related lipoproteins. While fast-migrating triglyceride-rich lipoprotein (fTRL) subfraction contained both chylomicrons and VLDL fraction, slow TRL (sTRL) only contained VLDL. cITP fLDL also contained VLDL fraction, i.e., beta-VLDL. Levels of cITP fTRL and sTRL were significantly correlated with serum levels of TG, RLP-C, apo C-II, and C-III. Levels of cITP sTRL were also correlated with apo E. Levels of cITP fLDL were positively correlated with not only LDL-C levels but also levels of TG, RLP-C, apo C-II, C-III, and E.

CONCLUSION

cITP fast LDL correlated with RLP-C levels and modified the relation between RLP-C and TG levels.

Potent Capillary Isotachophoresis (cITP) for Analyzing a Marker of Coronary Heart Disease Risk and Electronegative Low-Density Lipoprotein (LDL) in Small Dense LDL Fraction

BACKGROUND

The potency and usefulness of capillary isotachophoresis (cITP) for assessing whole-serum lipoprotein profiles and quantifying electronegative low-density lipoprotein (LDL) has been previously reported.

METHODS AND RESULTS

A new cITP method to measure electronegative LDL in the small dense LDL fraction has been established. Both electronegative LDL and electronegative LDL in the small dense LDL fraction decreased after treatment with fenofibrate.

CONCLUSIONS

This method appears to be useful for analyzing a marker of coronary heart disease risk and may be suitable for evaluating the effects of hypolipidemic agents.