Differential effect of two nicotinic acid preparations on low-density lipoprotein subclass distribution in patients classified as low-density lipoprotein pattern A, B, or I

Effects of niacin on apo A1 and B levels: a systematic review and meta-analysis of randomised controlled trials

Niacin has been investigated for its potential impact on lipid metabolism and cardiovascular health. This meta-analysis aims to systematically evaluate the effects of niacin interventions on apo A1 and apo B levels, key regulators of lipoprotein metabolism and markers of cardiovascular risk. A comprehensive search of the literature was performed on five databases of PubMed, Scopus, Web of Science, Embase and Cochrane library, from inception up to 15 July 2023. This search identified 1452 publications, from which twelve randomised controlled trials met the inclusion criteria. The intervention dosages ranged from 500 to 3000 mg/d, and the study durations spanned from 6 to 102·8 weeks. The niacin intervention demonstrated a significant reduction in apo B levels (weighted mean differences (WMD): -24·37 mg/dl, P = 0·01). Subgroup analyses indicated that intervention duration played a role, with trials of ≤ 16 weeks showing a greater reduction in apo B. Regarding apo A1, niacin significantly increased its levels (WMD: 8·23 mg/dl, P < 0·001). Subgroup analyses revealed that the beneficial effects of niacin on apo A1 were observed at a dosage of > 1500 mg/d (P < 0·001), and extended-release niacin was more effective compared with other forms (P < 0·001). According to the Begg's regression test, no publication bias was observed in this systematic review and meta-analysis. This meta-analysis highlights niacin's potential role in improving lipid profiles and cardiovascular health. Further well-designed clinical trials are needed to elucidate and confirm optimal dosages and durations of niacin interventions for influencing apo A1 and B.

Lipoprotein(a) and Atherosclerotic Cardiovascular Disease, the Impact of Available Lipid-Lowering Medications on Lipoprotein(a): An Update on New Therapies

OBJECTIVE

To review evidence of existing and new pharmacological therapies for lowering lipoprotein(a) (Lp[a]) concentrations and their impact on clinically relevant outcomes.

METHODS

We searched for literature pertaining to Lp(a) and pharmacological treatments in PubMed. We reviewed articles published between 1963 and 2020.

RESULTS

We found that statins significantly increased Lp(a) concentrations. Therapies that demonstrated varying degrees of Lp(a) reduction included ezetimibe, niacin, proprotein convertase subtilisin/kexin type 9 inhibitors, lipoprotein apheresis, fibrates, aspirin, hormone replacement therapy, antisense oligonucleotide therapy, and small interfering RNA therapy. There was limited data from large observational studies and post hoc analyses showing the potential benefits of these therapies in improving cardiovascular outcomes.

CONCLUSION

There are multiple lipid-lowering agents currently being used to treat hyperlipidemia that also have a Lp(a)-lowering effect. Two RNA therapies specifically targeted to lower Lp(a) are being investigated in phase 3 clinical trials and, thus far, have shown promising results. However, evidence is lacking to determine the clinical relevance of reducing Lp(a). At present, there is a need for large-scale, randomized, controlled trials to evaluate cardiovascular outcomes associated with lowering Lp(a).

Small Dense LDL: Scientific Background, Clinical Relevance, and Recent Evidence Still a Risk Even with ‘Normal’ LDL-C Levels

Residual cardiovascular disease event risk, following statin use and low-density lipoprotein cholesterol (LDL-C) reduction, remains an important and common medical conundrum. Identifying patients with significant residual risk, despite statin drug use, is an unmet clinical need. One pathophysiologic disorder that contributes to residual risk is abnormal distribution in lipoprotein size and density, which is referred to as lipoprotein heterogeneity. Differences in low density lipoprotein (LDL) composition and size have been linked to coronary heart disease (CHD) risk and arteriographic disease progression. The clinical relevance has been investigated in numerous trials since the 1950s. Despite this long history, controversy remains regarding the clinical utility of LDL heterogeneity measurement. Recent clinical trial evidence reinforces the relevance of LDL heterogeneity measurement and the impact on CHD risk prediction and outcomes. The determination of LDL subclass distribution improves CHD risk prediction and guides appropriate treatment.

Effects of NAD+ precursor supplementation on glucose and lipid metabolism in humans: a meta-analysis

BACKGROUND

This meta-analysis was performed to investigate the effects of nicotinamide adenine dinucleotide (NAD+) precursor supplementation on glucose and lipid metabolism in human body.

METHODS

PubMed, Embase, CENTRAL, Web of Science, Scopus databases were searched to collect clinical studies related to the supplement of NAD+ precursor from inception to February 2021. Then the retrieved documents were screened, the content of the documents that met the requirements was extracted. Meta-analysis and quality evaluation was performed detection were performed using RevMan5.4 software. Stata16 software was used to detect publication bias, Egger and Begg methods were mainly used. The main research terms of NAD+ precursors were Nicotinamide Riboside (NR), Nicotinamide Mononucleotide (NMN), Nicotinic Acid (NA), Nicotinamide (NAM). The changes in the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and fasting blood glucose were mainly concerned.

RESULTS

A total of 40 articles were included in the meta-analysis, with a sample of 14,750 cases, including 7406 cases in the drug group and 7344 cases in the control group. The results of meta-analysis showed that: NAD+ precursor can significantly reduce TG level (SMD = - 0.35, 95% CI (- 0.52, - 0.18), P < 0.0001), and TC (SMD = - 0.33, 95% CI (- 0.51, - 0.14), P = 0.0005), and LDL (SMD = - 0.38, 95% CI (- 0.50, - 0.27), P < 0.00001), increase HDL level (SMD = 0.66, 95% CI (0.56, 0.76), P < 0.00001), and plasma glucose level in the patients (SMD = 0.27, 95% CI (0.12, 0.42), P = 0.0004). Subgroup analysis showed that supplementation of NA had the most significant effect on the levels of TG, TC, LDL, HDL and plasma glucose.

CONCLUSIONS

In this study, a meta-analysis based on currently published clinical trials with NAD+ precursors showed that supplementation with NAD+ precursors improved TG, TC, LDL, and HDL levels in humans, but resulted in hyperglycemia, compared with placebo or no treatment. Among them, NA has the most significant effect on improving lipid metabolism. In addition, although NR and NAM supplementation had no significant effect on improving human lipid metabolism, the role of NR and NAM could not be directly denied due to the few relevant studies at present. Based on subgroup analysis, we found that the supplement of NAD+ precursors seems to have little effect on healthy people, but it has a significant beneficial effect on patients with cardiovascular disease and dyslipidemia. Due to the limitation of the number and quality of included studies, the above conclusions need to be verified by more high-quality studies.

Role of niacin in current clinical practice

Despite significant risk reduction with statin therapy, there remains a residual cardiovascular risk. It has been seen that aggressive statin therapy in high risk patients may not lower the low-density lipoprotein cholesterol to goal in up to 40% of patients. Niacin is a potent high-density lipoprotein cholesterol-raising drug, and has been proposed as an attractive approach to reduce cardiac events in patients with or at risk of atherosclerotic cardiovascular disease. However, previous evidence for niacin has been challenged by negative outcomes in two large, randomized, controlled trials comparing niacin to placebo with background statin therapy. In this review, summarize the currently available evidence for the role of niacin treatment for reducing the risk of cardiovascular events in current practice.

Effect of extended-release niacin on plasma lipoprotein(a) levels: A systematic review and meta-analysis of randomized placebo-controlled trials

AIM

Lipoprotein(a) (Lp(a)) is a proatherogenic and prothrombotic lipoprotein. Our aim was to quantify the extended-release nicotinic acid Lp(a) reducing effect with a meta-analysis of the available randomized clinical trials.

METHODS

A meta-analysis and random-effects meta-regression were performed on data pooled from 14 randomized placebo-controlled clinical trials published between 1998 and 2015, comprising 17 treatment arms, which included 9013 subjects, with 5362 in the niacin arm.

RESULTS

The impact of ER niacin on plasma Lp(a) concentrations was reported in 17 treatment arms. Meta-analysis suggested a significant reduction of Lp(a) levels following ER niacin treatment (weighted mean difference - WMD: -22.90%, 95% CI: -27.32, -18.48, p<0.001). Results also remained similar when the meta-analysis was repeated with standardized mean difference as summary statistic (WMD: -0.66, 95% CI: -0.82, -0.50, p<0.001). When the studies were categorized according to the administered dose, there was a comparable effect between the subsets of studies with administered doses of <2000mg/day (WMD: -21.85%, 95% CI: -30.61, -13.10, p<0.001) and ≥2000mg/day (WMD: -23.21%, 95% CI: -28.41, -18.01, p<0.001). The results of the random-effects meta-regression did not suggest any significant association between the changes in plasma concentrations of Lp(a) with dose (slope: -0.0001; 95% CI: -0.01, 0.01; p=0.983), treatment duration (slope: -0.40; 95% CI: -0.97, 0.17; p=0.166), and percentage change in plasma HDL-C concentrations (slope: 0.44; 95% CI: -0.48, 1.36; p=0.350).

CONCLUSION

In this meta-analysis of randomized placebo-controlled clinical trials, treatment with nicotinic acid was associated with a significant reduction in Lp(a) levels.

Niacin in cardiovascular disease: recent preclinical and clinical developments

Niacin has been used for more than 50 years in the treatment of cardiovascular disease, although its use has largely been superseded by better-tolerated lipid-modulating interventions. There has been a renewed interest in the HDL-cholesterol raising properties of niacin, with the appreciation that substantial cardiovascular risk remains despite effective treatment of LDL-cholesterol. This coincides with increasing evidence that the complex functional properties of HDL are not well reflected by measurement of HDL-cholesterol alone. In addition to favorable actions on lipoproteins, it is becoming apparent that niacin may also possess lipoprotein independent or pleiotropic effects including the inhibition of inflammatory pathways mediated by its receptor GPR109A, which is expressed by adipocytes and some leukocytes. In this article we consider emerging and prior clinical trial data relating to niacin. We review recent data in respect of mechanisms of action on lipoproteins, which remain complex and incompletely understood. We discuss the recent reports of anti-inflammatory effects of niacin in adipocytes and through bone marrow derived cells and vascular endothelium. These novel observations come at an interesting time, with current imaging and outcome studies leaving outstanding questions on niacin efficacy in statin-treated patients.

Genetic testing for early detection of individuals at risk of coronary heart disease and monitoring response to therapy: challenges and promises

Coronary heart disease (CHD) often presents suddenly with little warning. Traditional risk factors are inadequate to identify the asymptomatic high-risk individuals. Early identification of patients with subclinical coronary artery disease using noninvasive imaging modalities would allow the early adoption of aggressive preventative interventions. Currently, it is impractical to screen the entire population with noninvasive coronary imaging tools. The use of relatively simple and inexpensive genetic markers of increased CHD risk can identify a population subgroup in which benefit of atherosclerotic imaging modalities would be increased despite nominal cost and radiation exposure. Additionally, genetic markers are fixed and need only be measured once in a patient's lifetime, can help guide therapy selection, and may be of utility in family counseling.

Niacin extended-release therapy in phase III clinical trials is associated with relatively low rates of drug discontinuation due to flushing and treatment-related adverse events: a pooled analysis

BACKGROUND AND OBJECTIVE

Niacin is a highly effective agent for increasing low high-density lipoprotein cholesterol (HDL-C) levels. It also has beneficial effects on key pro-atherogenic lipoprotein parameters. However, the side effect of flushing can challenge patient adherence to treatment. In this study, we pooled safety data from available trials of at least 16 weeks' duration to evaluate the impact of flushing on patient adherence to niacin extended-release (NER) therapy.

METHODS

Data were pooled from eight NER studies (administered as NER with a maximum dosage of 1000, 1500, and 2000 mg/day, either as monotherapy or in combination with simvastatin 20 or 40 mg/day [NER/S], or lovastatin 20 or 40 mg/day [NER/L]) to evaluate rates of study discontinuation due to flushing or any treatment-related adverse events.

RESULTS

While 66.6% of patients experienced flushing, only 5.2% of patients discontinued treatment due to flushing. Of the total number of patients treated with NER (n = 307), NER/S (n = 912), or NER/L (n = 928), 34 (11%), 105 (11%), and 127 (14%) patients discontinued due to any treatment-related adverse event, respectively, while 14 (5%), 43 (5%), and 55 (6%) discontinued due to flushing. Discontinuation for flushing did not differ with regard to maximum dose, or to the presence or type of statin combined with NER.

CONCLUSION

Although flushing was common with NER treatment, discontinuation due to flushing occurred in only 5-6% of patients in this pooled analysis. This could be due to several factors, including the fact that all patients in the NER trials were educated about flushing and its management. Translation of methodology employed in these trials into clinical practice may improve long-term adherence to NER therapy, which would enhance the therapeutic benefit of NER for reducing cardiovascular risk.

Family coronary heart disease: a call to action

A family history of coronary heart disease (CHD) is an accepted risk factor for cardiovascular events and is independent of common CHD risk factors. Advances in the understanding of genetic influences on CHD risk provide the opportunity to apply this knowledge and improve patient care. Utility of inherited cardiovascular risk testing exists by utilizing both phenotypes and genotypes and includes improved CHD risk prediction, selection of the most appropriate treatment, prediction of outcome, and family counseling. The major impediment to widespread clinical adoption of this concept involves un-reimbursed staff time, educational needs, access to a standardized and efficient assessment mechanism, and privacy issues. The link between CHD and inheritance is indisputable and the evidence strong and consistent. For clinicians, the question is how to utilize this information, in an efficient manner, in order to improve patient care and detection of high-risk family members.

Combination of niacin extended-release and simvastatin results in a less atherogenic lipid profile than atorvastatin monotherapy

OBJECTIVE

To compare the effects of combination niacin extended-release + simvastatin (NER/S) versus atorvastatin alone on apolipoproteins and lipid fractions in a post hoc analysis from SUPREME, a study which compared the lipid effects of niacin extended-release + simvastatin and atorvastatin in patients with hyperlipidemia or mixed dyslipidemia.

PATIENTS AND METHODS

Patients (n = 137) with dyslipidemia (not previously receiving statin therapy or having discontinued any lipid-altering treatment 4-5 weeks prior to the study) received NER/S (1000/40 mg/day for four weeks, then 2000/40 mg/day for eight weeks) or atorvastatin 40 mg/day for 12 weeks. Median percent changes in apolipoprotein (apo) A-1, apo B, and the apo B:A-I ratio, and nuclear magnetic resonance lipoprotein subclasses from baseline to week 12 were compared using the Wilcoxon rank-sum test and Fisher's exact test.

RESULTS

NER/S treatment produced significantly greater percent changes in apo A-I and apo B:A-I, and, at the final visit, apo B < 80 mg/dL was attained by 59% versus 33% of patients, compared with atorvastatin treatment (P = 0.003). NER/S treatment resulted in greater percent reductions in calculated particle numbers for low-density lipoprotein (LDL, 52% versus 43%; P = 0.022), small LDL (55% versus 45%; P = 0.011), very low-density lipoprotein (VLDL) and total chylomicrons (63% versus 39%; P < 0.001), and greater increases in particle size for LDL (2.7% versus 1.0%; P = 0.007) and VLDL (9.3% versus 0.1%; P < 0.001), compared with atorvastatin.

CONCLUSION

NER/S treatment significantly improved apo A-I levels and the apo B:A-I ratio, significantly lowered the number of atherogenic LDL particles and VLDL and chylomicron particles, and increased the mean size of LDL and VLDL particles, compared with atorvastatin.

Molecular pathways and agents for lowering LDL-cholesterol in addition to statins

Recent guidelines in North America and Europe recommend lowering low density lipoprotein associated cholesterol (LDLC) to achieve optimal coronary heart disease risk reduction. Statins have been the therapy of choice and proven successful and relatively safe. However, we are now facing new challenges and it appears that additional or alternative drugs are urgently needed. This boosts research in the field, reopening old cases like other inhibitors of cholesterol synthesis or making attractive tools from the latest technologies like gene silencing by anti-sense oligonucleotides. LDLs are cholesterol-enriched lipoproteins stabilized by the hepatic apolipoprotein B100, and derived from TG rich very low density lipoprotein. This review focuses on the molecular pathways involved in plasma LDLC production and elimination, in particular cholesterol absorption and the hepatobiliary route, apoB100 and VLDL production, and LDL clearance via the LDL receptor. We will identify important or rate-limiting proteins (including Niemann-Pick C1-like 1 (NPC1L1), microsomal TG transfer protein (MTP), acyl-coenzyme A/cholesterol acyltransferase (ACAT), Acyl-CoA:diacylglycerol acyltransferases 2 (DGAT2), proprotein convertase subtilisin kexin type 9 (PCSK9)), and nuclear receptors (farnesoid X receptor (FXR), thyroid hormone receptor (TR)) that constitute interesting therapeutic targets. Numerous compounds already in use modulate these pathways, such as phytosterols, ezetimibe, bile acids sequestrants, niacin, and fibrates. Many pathways can be considered to lower LDLC, but the road has been paved with disappointments and difficulties. With new targets identified and diversification of the drugs, a new era for better LDLC management is plausible.

The mechanism and mitigation of niacin-induced flushing

AIMS

To summarise the metabolic responses to niacin that can lead to flushing and to critically evaluate flushing mitigation research.

METHODS AND RESULTS

This comprehensive review of the mechanism of action of niacin-induced flushing critically evaluates research regarding flushing mitigating formulations and agents. Niacin induces flushing through dermal Langerhans cells where the activation of G protein-coupled receptor 109A (GPR109A) increases arachidonic acid and prostaglandins, such as prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)), subsequently activating prostaglandin D(2) receptor (DP(1)), prostaglandin E(2) receptor (EP(2)) and prostaglandin E receptor 4 (EP(4)) in capillaries and causing cutaneous vasodilatation. Controlling niacin absorption rates, inhibiting prostaglandin production, or blocking DP(1), EP(2) and EP(4) receptors can inhibit flushing. Niacin extended-release (NER) formulations have reduced flushing incidence, duration and severity relative to crystalline immediate-release niacin with similar lipid efficacy. Non-steroidal anti-inflammatory drugs (NSAIDs), notably aspirin given 30 min before NER at bedtime, further reduce flushing. An antagonist to the DP(1) receptor (laropiprant) combined with an ER niacin formulation can reduce flushing; however, significant residual flushing occurs with clinically-relevant dosages.

CONCLUSIONS

Niacin is an attractive option for treating dyslipidemic patients, and tolerance to niacin-induced flushing develops rapidly. Healthcare professionals should particularly address flushing during niacin dose titration.

Effect of combination nicotinic acid and gemfibrozil treatment on intermediate density lipoprotein, and subclasses of low density lipoprotein and high density lipoprotein in patients with combined hyperlipidemia

The goal of this study was to determine, using analytic ultracentrifugation, the effect of nicotinic acid alone or nicotinic acid added to gemfibrozil on lipoprotein subclass distribution, including intermediate-density lipoprotein (IDL; low-density to very low density flotation rate [S(f)] 12 to 20); low-density lipoprotein (LDL) subfractions LDL-I (S(f) 7 to 12), LDL-II (S(f) 5 to 7), LDL-III (S(f) 3 to 5), and LDL-IV (S(f) 0 to 3); and high-density lipoprotein (HDL) subfractions HDL(2) (high-density flotation rate 3.5 to 9.0) and HDL(3) (high-density flotation rate 0 to 3.5). Patients with combined hyperlipidemia were randomized to nicotinic acid (1,500 mg/day) plus placebo or nicotinic acid plus gemfibrozil (1,200 mg/d) for 12 weeks. Baseline characteristics were similar between the 2 groups, and mean LDL cholesterol (180 +/- 33 mg/dl) and triglycerides (310 +/- 126 mg/dl) were typical for patients with combined hyperlipidemia. Treatment with nicotinic acid resulted in a reduction in dense LDL (S(f) 5 to 7; p = 0.02), which was counterbalanced by an increase in buoyant LDL (S(f) 7 to 12; p = 0.03) that resulted in no significant LDL mass or LDL cholesterol change. IDL was reduced (p = 0.005) and HDL(2) increased by 143% (p = 0.004). The combination of nicotinic acid and gemfibrozil resulted in a further 17.8% reduction in apolipoprotein B (p = 0.06), a further 33.8% reduction in IDL (p = 0.06), and a greater reduction in the apolipoprotein B/apolipoprotein A-I ratio (p = 0.02). The combination of nicotinic acid and gemfibrozil reduced atherogenic by IDL 71%, dense LDL-III by 52%, and apolipoprotein B by 37% and increased protective HDL(2) by 90%. In conclusion, this investigation revealed that a combination of a fibric acid derivative and nicotinic acid offers greater improvement in detailed lipoprotein subclass distribution and apolipoprotein ratios than monotherapy.

Is it LDL particle size or number that correlates with risk for cardiovascular disease?

The role of low-density lipoprotein cholesterol (LDL-C) in the pathogenesis of cardiovascular disease (CVD) and the clinical benefit of lowering LDL-C in high-risk patients is well established. What remains controversial is whether we are using the best measure(s) of LDL characteristics to identify all individuals who are at CVD risk or if they would benefit from specific therapies. Despite the successful LDL-C reduction trials, substantial numbers of patients continue to have clinical events in the treatment groups. The size of LDL particles and assessment of the number of LDL particles (LDL-Num) have been suggested as a more reliable method of atherogenicity. Each LDL particle has one apoprotein B-100 measure attached; therefore, determination of whole plasma apoprotein B can be considered the best measure of LDL-Num. Because the cholesterol content per LDL particle exhibits large interindividual variation, the information provided by LDL-C and LDL-Num is not equivalent. Individuals with the same level of LDL-C may have higher or lower numbers of LDL particles and, as a result, may differ in terms of absolute CVD risk. LDL particle size and number provide independent measures of atherogenicity and are strong predictors of CVD.

The differential effects of thiazolidindiones on atherogenic dyslipidemia in type 2 diabetes: what is the clinical significance?

BACKGROUND

Diabetic dyslipidemia is typically characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol and a concomitant increase in atherogenic small dense low-density lipoproteins. Thiazolidindiones are able to lower the levels of fasting glucose and glycated hemoglobin significantly by improving insulin sensitivity, as well as improving some aspects of diabetic dyslipidemia: total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol tend to increase while triglycerides are generally decreased.

OBJECTIVE

This paper reviewed the effects of pioglitazone and rosiglitazone on atherogenic diabetic dyslipidemia, in particular on small dense low-density lipoprotein particles.

METHODS

A literature search (by Medline and Scopus) was performed up to 15 March 2008. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Pioglitazone showed an additional beneficial effect on triglycerides, high-density lipoprotein cholesterol and the levels of small dense low-density lipoprotein compared to rosiglitazone.

CONCLUSIONS

Since recent studies have suggested that these agents may also have a differential effect on long-term cardiovascular end-points despite similar improvements in glycated hemoglobin and insulin sensitivity, the different impact on atherogenic diabetic dyslipidemia may help to explain these findings.

Reduction in triglyceride level with N-3 polyunsaturated fatty acids in HIV-infected patients taking potent antiretroviral therapy: a randomized prospective study

To assess the evolution of triglyceride (TG) levels in HIV-infected patients receiving stable potent antiretroviral therapy treated with N-3 polyunsaturated fatty acids (PUFAs), a prospective double-blind randomized design for a reliable assessment of TG evolution was performed. One hundred twenty-two patients with TG levels >2 g/L and < or =10 g/L after a 4-week diet (baseline TG: 4.5 +/- 1.9 g/L) were randomized for 8 weeks to N-3 PUFAs (2 capsules containing 1 g of fish oil 3 times daily, n = 60), or placebo (1 g of paraffin oil capsules, n = 62). An 8-week open-label phase of N-3 PUFAs followed. Evaluation criteria were TG percent change at week 8, percentage of responders (normalization or > or =20% TG decrease), and safety issues. Ten patients with baseline TG levels >10 g/L were not randomized and received N-3 PUFAs as open treatment. The difference (PUFA - placebo) in TG percent change at week 8 was -24.6% (range: -40.9% to -8.4%; P = 0.0033), the median was -25.5% in the PUFA group versus 1% in the placebo group, and mean TG levels at week 8 were 3.4 +/- 1.8 g/L and 4.8 +/- 3.1 g/L, respectively. TG levels were normalized in 22.4% (PUFA) versus 6.5% (placebo) of patients (P = 0.013) with a > or =20% reduction in 58.6% (PUFA) versus 33.9% (placebo) of patients (P = 0.007). Under the open-label phase of N-3 PUFAs, the decrease in TG levels was sustained at week 16 for patients in the PUFA group (mean TG: 3.4 +/- 1.7 g/L), whereas a 21.2% decrease in TG levels occurred for patients in the placebo group (mean TG: 3.3 +/- 1.4 g/L). No significant differences were observed between groups in the occurrence of adverse events. The median TG change at week 8 was -43.6% (range: Q1-Q3; 95% CI: -66.5% to -4.6%) for patients with baseline TG levels >10 g/L. The difference in mean total cholesterol between groups (PUFA - placebo) at week 8 was -8.5% (P = 0.0117). This study demonstrated the efficacy of PUFAs to lower elevated TG levels in treated HIV-infected hypertriglyceridemic patients. N-3 PUFAs have a good safety profile.

Polyacrylamide gradient gel electrophoresis of lipoprotein subclasses

High-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins are heterogeneous cholesterol-containing particles that differ in their metabolism, environmental interactions, and association with disease. Several protocols use polyacrylamide gradient gel electrophoresis (GGE) to separate these major lipoproteins into known subclasses. This article provides a brief history of the discovery of lipoprotein heterogeneity and an overview of relevant lipoprotein metabolism, highlighting the importance of the subclasses in the context of their metabolic origins, fates, and clinical implications. Various techniques using polyacrylamide GGE to assess HDL and LDL heterogeneity are described, and how the genetic and environmental determinations of HDL and LDL affect lipoprotein size heterogeneity and the implications for cardiovascular disease are outlined.

Gemfibrozil reduces small low-density lipoprotein more in normolipemic subjects classified as low-density lipoprotein pattern B compared with pattern A

We tested the hypothesis that gemfibrozil has a differential effect on low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclass distributions and postprandial lipemia that is different in subjects classified as having LDL subclass pattern A or LDL pattern B who do not have a classic lipid disorder. Forty-three normolipemic subjects were randomized to gemfibrozil (1,200 mg/day) or placebo for 12 weeks. Lipids and lipoproteins were determined by enzymatic methods. The mass concentrations of lipoproteins in plasma were determined by analytic ultracentrifugation and included the S(f) intervals: 20 to 400 (very LDL), 12 to 20 (intermediate-density lipoprotein), 0 to 12 (LDL), and HDL(2) mass (F(1.20) 3.5 to 9.0) and HDL(3) mass (F(1.20) 0 to 3.5). Postprandial measurements of triglycerides and lipoprotein(a) were taken after the patients consumed a 500 kcal/M(2) test meal. Treatment with gemfibrozil, compared with placebo, significantly reduced fasting plasma triglycerides (difference from placebo +/- SE; -50.2 +/- 20.6 mg/dl, p = 0.02), total cholesterol (-16.4 +/- 7.5 mg/dl, p = 0.04), apolipoprotein B (-16.1 +/- 5.5 mg/dl, p = 0.006), very LDL mass of S(f) 20 to 400 (-50.8 +/- 24.1 mg/dl, p = 0.02), S(f) 20 to 60 (-17.5 +/- 8.5 mg/dl, p = 0.05), S(f) 60 to 100 (-16.2 +/- 8.1 mg/dl, p = 0.05), and increased peak S(F) (0.48 +/- 0.27 Svedberg, p = 0.08). Gemfibrozil reduced the postprandial triglyceride level significantly at 3 (p = 0.04) and 4 (p = 0.05) hours after the test meal. A significantly different subclass response to gemfibrozil was observed in those with LDL pattern A versus B. Those with LDL pattern B had a significantly greater reduction in the small LDL mass S(f) 0 to 7 (p = 0.04), specifically regions S(f) 0 to 3 (p = 0.009) and S(f) 3 to 5 (p = 0.009). In conclusion, normolipemic subjects with either predominantly dense or buoyant LDL respond differently to gemfibrozil as determined by the changes in LDL subclass distribution. Thus, treatment with gemfibrozil may have additional antiatherogenic effects in those with LDL pattern B by decreasing small dense LDL that is not apparent in those with pattern A.

Clinical utility of extended-release niacin: update and summary

In the treatment of dyslipidemia and coronary heart disease, niacin extended-release (ER) (Niaspan) uniquely targets the atherogenic lipid abnormalities of the metabolic syndrome. Niacin ER raises high-density lipoprotein cholesterol more effectively than other agents, while reducing triglyceride and lipoprotein(a) levels and increasing low-density lipoprotein particle size. It is formulated to minimize the toxicities and adverse effects associated with other niacin formulations, making niacin ER more tolerable for patients. Previous concerns of hyperglycemia have been addressed by numerous studies demonstrating that morbidity and mortality benefits outweigh potential increases in glucose levels. Niacin ER is an important lipid-lowering agent in preventing fatal and nonfatal coronary events and slowing the progression of atherosclerosis.

Nicotinic acid: the broad-spectrum lipid drug. A 50th anniversary review

Nicotinic acid has, like the Roman God Janus, two faces. One is the vitamin. The other is the broad-spectrum lipid drug. The Canadian pathologist Rudolf Altschul discovered 50 years ago that nicotinic acid in gram doses lowered plasma levels of cholesterol. From the point of view of treatment of the dyslipidaemias that are risk factors for clinical atherosclerosis nicotinic acid is a miracle drug. It lowers the levels of all atherogenic lipoproteins--VLDL and LDL with subclasses as well as Lp(a)--and in addition it raises more than any other drug the levels of the protective HDL lipoproteins. Trials have shown that treatment with nicotinic acid reduces progression of atherosclerosis, and clinical events and mortality from coronary heart disease. The new combination treatment with statin-lowering LDL and nicotinic acid-raising HDL is reviewed. A basic effect of nicotinic acid is the inhibition of fat-mobilizing lipolysis in adipose tissue leading to a lowering of plasma free fatty acids, which has many metabolic implications which are reviewed. The very recent discovery of a nicotinic acid receptor and the finding that the drug stimulates the expression of the ABCA 1 membrane cholesterol transporter have paved the way for exciting and promising new 50 years in the history of nicotinic acid.

Prolonged-Release Nicotinic Acid

Prolonged-release (PR) nicotinic acid (niacin) [Niaspan] is an oral, once-daily formulation of the lipid-modifying drug designed to produce less vasodilatory flushing than crystalline immediate-release (IR) nicotinic acid and less hepatotoxicity than previous sustained-release formulations of nicotinic acid.PR nicotinic acid appears to retain the same level of efficacy as crystalline IR nicotinic acid and be better tolerated than older nicotinic acid formulations. Nicotinic acid has beneficial effects on all traditional blood lipid and lipoprotein fractions and is the most effective agent for increasing high-density lipoprotein (HDL)-cholesterol (HDL-C) and reducing lipoprotein(a). The effects of PR nicotinic acid are often additive when used in combination with HMG-CoA reductase inhibitors (statins), making it a useful addition when lipid goals are not achieved with the usual statin monotherapy or when additional correction of a specific lipid abnormality is required. PR nicotinic acid also slows atherosclerotic progression and even appears to produce regression of atherosclerosis in patients on stable statin therapy. PR nicotinic acid is a logical drug choice for treating atherogenic dyslipidaemia commonly associated with type 2 diabetes mellitus and the metabolic syndrome, and has been shown to be effective in patients with diabetes without adversely affecting glycaemic control in the majority of patients. The incidence of vasodilatory flushing with PR nicotinic acid is lower than with IR nicotinic acid and it decreases substantially over time as tolerance develops. To date, there has been no clinically significant hepatotoxicity observed with PR nicotinic acid. Therefore, once-daily PR nicotinic acid appears to maximise the potential benefits of nicotinic acid, while minimising any historical tolerability or safety concerns.