Elevated baseline triglyceride levels modulate effects of HMGCoA reductase inhibitors on plasma lipoproteins

Safety and efficacy of colesevelam hydrochloride in combination with fenofibrate for the treatment of mixed hyperlipidemia

OBJECTIVE

The aim of this study was to evaluate the amount of low-density lipoprotein cholesterol (LDL-C) reduction achieved by adding the specifically engineered bile acid sequestrant (SE-BAS) colesevelam HCl to a stable dose of fenofibrate in patients with mixed hyperlipidemia.

RESEARCH DESIGN AND METHODS

Patients with mixed hyperlipidemia (n = 129) were enrolled in a randomized, double-blind, placebo-controlled, parallel-group study investigating the efficacy of fenofibrate plus colesevelam HCl versus fenofibrate monotherapy. After a 4- to 8-week washout period, subjects received fenofibrate 160 mg/day for 8 weeks and were then randomized to receive colesevelam HCl 3.75 g/day or placebo, in addition to fenofibrate 160 mg/day, for 6 weeks.

MAIN OUTCOMES MEASURES

The primary efficacy endpoint was mean percent change in LDL-C during randomized treatment. Secondary endpoints included absolute and percent changes in mean levels of LDL-C, triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, total cholesterol (TC), and apolipoproteins (apo) A-I and B during randomized treatment and from washout to end of randomized treatment.

RESULTS

Of the 129 patients randomized to treatment, 119 completed the study. After 6 weeks of treatment, fenofibrate plus colesevelam HCl produced a mean percent change in LDL-C of -10.4% versus +2.3% with fenofibrate monotherapy (p < 0.0001). Fenofibrate plus colesevelam HCl was significantly more effective than fenofibrate alone at reducing levels of non-HDL-C, TC, and apo B (p < or = 0.0002). Colesevelam HCl did not significantly affect the TG-lowering effects of fenofibrate. Both treatment regimens were safe and well tolerated.

CONCLUSIONS

Compared with fenofibrate monotherapy in patients with mixed hyperlipidemia, fenofibrate/colesevelam HCl combination therapy significantly reduced mean LDL-C, non-HDL-C, TC, and apo B levels without significantly affecting the TG-lowering or HDL-C-raising effects of fenofibrate. Fenofibrate/colesevelam HCl combination therapy is a safe, useful alternative for the treatment of mixed hyperlipidemia.

Baseline levels of low-density lipoprotein cholesterol and lipoprotein (a) and the AvaII polymorphism of the low-density lipoprotein receptor gene influence the response of low-density lipoprotein cholesterol to pravastatin treatment

To investigate some individual and genetic factors that may influence the response of low-density lipoprotein cholesterol (LDL-C) to pravastatin treatment, we recruited 440 subjects with hypercholesterolemia (mean age, 57 years; 43% men) from 21 primary health care centers-outpatient clinics into a prospective, multicentered intervention trial. Pravastatin (20 mg/d) was prescribed for 16 weeks. The main outcome was the percentage variation in LDL-C concentration relative to baseline. Blood analyses and genotyping were performed centrally. The results indicated that LDL-C decreased by 20.5% (range, +21% to -66%) after pravastatin treatment. Baseline concentration of LDL-C (the higher the concentration, the greater the decrease), lipoprotein (a) levels (the lower the concentration, the greater the response), and Ava II polymorphism of the LDL-receptor gene significantly influenced the hypolipemic effect ( P < .001, P = .014, and P = .004, respectively). These 3 factors combined explained 10.6% of the variation in LDL-C response. Age, sex, smoking habit, alcohol consumption, body mass index, and apolipoprotein E genotype had no significant effect on response. We conclude that baseline levels of LDL-C and lipoprotein (a) together with the Ava II polymorphism of the LDL-receptor gene have a significant influence on the LDL-C response to pravastatin treatment in patients monitored in a standard primary health care outpatient clinic setting.

Haplotypes of the cholesteryl ester transfer protein gene predict lipid-modifying response to statin therapy

Cholesteryl ester transfer protein (CETP) plays a central role in high-density lipoprotein (HDL) metabolism. Single nucleotide polymorphisms (SNPs) and haplotypes in the CETP gene were determined in 98 patients with untreated dyslipidemias and analyzed for associations with plasma CETP and plasma lipids before and during statin treatment. Individual CETP SNPs and haplotypes were both significantly associated with CETP enzyme mass and activity. However, only certain CETP haplotypes, but not individual SNPs, significantly predicted the magnitude of change in HDL cholesterol (HDL-C) and triglycerides. After adjusting for covariates and multiple testing, the TTCAAA haplotype showed a gene-dose effect in predicting the HDL-C increase (P=0.03), while the TTCAAAGGG and AAAGGG haplotypes predicted a decrease in triglycerides (P=0.04 both). This is the first study to demonstrate that SNP haplotypes derived from allelic SNP combinations in the CETP gene were more informative than single SNPs in predicting the response to lipid-modifying therapy with statins.

Sequencing by hybridization (SBH): advantages, achievements, and opportunities

Efficient DNA sequencing of the genomes of individual species and organisms is a critical task for the advancement of biological sciences, medicine and agriculture. Advances in modern sequencing methods are needed to meet the challenge of sequencing such megabase to gigabase quantities of DNA. Two possible strategies for DNA sequencing exist: direct methods, in which each base position in the DNA chain is determined individually (e.g., gel sequencing or pyrosequencing), and indirect methods, in which the DNA sequence is assembled based on experimental determination of oligonucleotide content of the DNA chain. One promising indirect method is sequencing by hybridization (SBH), in which sets of oligonucleotides are hybridized under conditions that allow detection of complementary sequences in the target nucleic acid. The unprecedented sequence search parallelism of the SBH method has allowed development of high-throughput, low-cost, miniaturized sequencing processes on arrays of DNA samples or probes. Newly developed SBH methods use DNA ligation to combine relatively small sets of short probes to score potentially tens of millions of longer oligonucleotide sequences in a target DNA. Such combinatorial approaches allow analysis of DNA samples of up to several kilobases (several times longer than allowed by current direct methods) for a variety of DNA sequence analysis applications, including de novo sequencing, resequencing, mutation/SNP discovery and genotyping, and expression monitoring. Future advances in biochemistry and implementation of detection methods that allow single-molecule sensitivity may provide the necessary miniaturization, specificity, and multiplexing efficiency to allow routine whole genome analysis in a single solution-based hybridization experiment.