Homocysteine and lipid lowering agents. A comparison between atorvastatin and fenofibrate in patients with mixed hyperlipidemia

Impact of Statin or Fibrate Therapy on Homocysteine Concentrations: A Systematic Review and Meta-analysis

INTRODUCTION

Statins and fibrates are two lipid-lowering drugs used in patients with dyslipidemia. This systematic review and meta-analysis were conducted to determine the magnitude of the effect of statin and fibrate therapy on serum homocysteine levels.

METHODS

A search was undertaken of the PubMed, Scopus, Web of Science, Embase, and Google Scholar electronic databases up to 15 July 2022. Primary endpoints focused on plasma homocysteine levels. Data were quantitatively analyzed using fixed or random- effect models, as appropriate. Subgroup analyses were conducted based on the drugs and hydrophilic-lipophilic balance of statins.

RESULTS

After screening 1134 papers, 52 studies with a total of 20651 participants were included in the meta-analysis. The analysis showed a significant decrease in plasma homocysteine levels after statin therapy (WMD: -1.388 μmol/L, 95% CI: [-2.184, -0.592], p = 0.001; I2 = 95%). However, fibrate therapy significantly increased plasma homocysteine levels (WMD: 3.459 μmol/L, 95% CI: [2.849, 4.069], p < 0.001; I2 = 98%). The effect of atorvastatin and simvastatin depended on the dose and duration of treatment (atorvastatin [coefficient: 0.075 [0.0132, 0.137]; p = 0.017, coefficient: 0.103 [0.004, 0.202]; p = 0.040, respectively] and simvastatin [coefficient: -0.047 [-0.063, -0.031]; p < 0.001, coefficient: 0.046 [0.016, 0.078]; p = 0.004]), whereas the effect of fenofibrate persisted over time (coefficient: 0.007 [-0.011, 0.026]; p = 0.442) and was not altered by a change in dosage (coefficient: -0.004 [-0.031, 0.024]; p = 0.798). In addition, the greater homocysteine- lowering effect of statins was associated with higher baseline plasma homocysteine concentrations (coefficient: -0.224 [-0.340, -0.109]; p < 0.001).

CONCLUSION

Fibrates significantly increased homocysteine levels, whereas statins significantly decreased them.

Effect of statin treatment on homocysteine concentrations: an updated systematic review and meta-analysis with meta-regression

BACKGROUND AND AIMS

Statins might exert atheroprotective effects through lowering the pro-atherogenic amino acid homocysteine. We conducted an updated systematic review and meta-analysis of the effect of statins on circulating homocysteine.

METHODS

A systematic literature search was conducted in PubMed, Web of Science, and Scopus, from inception to July 2021. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for analytical studies. Certainty of evidence was assessed using GRADE.

RESULTS

In 61 treatment arms in 2,218 patients (mean age 55 years, 52% males), statins significantly reduced homocysteine concentrations (weighted mean difference, WMD = -2.46 µmol/L, 95% CI -3.17 to -1.75 µmol/L, p < 0.001; high certainty of evidence). Similar results were observed in a subgroup of 10 randomized placebo-controlled studies (WMD = -2.45 µmol/L, 95% CI -4.43 to -0.47 µmol/L, p = 0.015). The extreme heterogeneity observed was virtually removed in a subgroup of 10 studies using fluorescence polarization immunoassay for homocysteine measurement. There was no publication bias. In sensitivity analysis, the pooled WMD values were not modified when individual studies were sequentially removed. In meta-regression, the WMD was significantly associated with proportion of males and publication year.

CONCLUSIONS

Statins significantly lower homocysteine concentrations.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE

OBJECTIVE

The development of these guidelines is mandated by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPGs).

METHODS

Recommendations are based on diligent reviews of the clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.

RESULTS

The Executive Summary of this document contains 87 recommendations of which 45 are Grade A (51.7%), 18 are Grade B (20.7%), 15 are Grade C (17.2%), and 9 (10.3%) are Grade D. These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world medical care. The evidence base presented in the subsequent Appendix provides relevant supporting information for Executive Summary Recommendations. This update contains 695 citations of which 203 (29.2 %) are EL 1 (strong), 137 (19.7%) are EL 2 (intermediate), 119 (17.1%) are EL 3 (weak), and 236 (34.0%) are EL 4 (no clinical evidence).

CONCLUSION

This CPG is a practical tool that endocrinologists, other health care professionals, health-related organizations, and regulatory bodies can use to reduce the risks and consequences of dyslipidemia. It provides guidance on screening, risk assessment, and treatment recommendations for a range of individuals with various lipid disorders. The recommendations emphasize the importance of treating low-density lipoprotein cholesterol (LDL-C) in some individuals to lower goals than previously endorsed and support the measurement of coronary artery calcium scores and inflammatory markers to help stratify risk. Special consideration is given to individuals with diabetes, familial hypercholesterolemia, women, and youth with dyslipidemia. Both clinical and cost-effectiveness data are provided to support treatment decisions.

ABBREVIATIONS

4S = Scandinavian Simvastatin Survival Study A1C = glycated hemoglobin AACE = American Association of Clinical Endocrinologists AAP = American Academy of Pediatrics ACC = American College of Cardiology ACE = American College of Endocrinology ACS = acute coronary syndrome ADMIT = Arterial Disease Multiple Intervention Trial ADVENT = Assessment of Diabetes Control and Evaluation of the Efficacy of Niaspan Trial AFCAPS/TexCAPS = Air Force/Texas Coronary Atherosclerosis Prevention Study AHA = American Heart Association AHRQ = Agency for Healthcare Research and Quality AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides trial ASCVD = atherosclerotic cardiovascular disease ATP = Adult Treatment Panel apo = apolipoprotein BEL = best evidence level BIP = Bezafibrate Infarction Prevention trial BMI = body mass index CABG = coronary artery bypass graft CAC = coronary artery calcification CARDS = Collaborative Atorvastatin Diabetes Study CDP = Coronary Drug Project trial CI = confidence interval CIMT = carotid intimal media thickness CKD = chronic kidney disease CPG(s) = clinical practice guideline(s) CRP = C-reactive protein CTT = Cholesterol Treatment Trialists CV = cerebrovascular CVA = cerebrovascular accident EL = evidence level FH = familial hypercholesterolemia FIELD = Secondary Endpoints from the Fenofibrate Intervention and Event Lowering in Diabetes trial FOURIER = Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects With Elevated Risk trial HATS = HDL-Atherosclerosis Treatment Study HDL-C = high-density lipoprotein cholesterol HeFH = heterozygous familial hypercholesterolemia HHS = Helsinki Heart Study HIV = human immunodeficiency virus HoFH = homozygous familial hypercholesterolemia HPS = Heart Protection Study HPS2-THRIVE = Treatment of HDL to Reduce the Incidence of Vascular Events trial HR = hazard ratio HRT = hormone replacement therapy hsCRP = high-sensitivity CRP IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial IRAS = Insulin Resistance Atherosclerosis Study JUPITER = Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin LDL-C = low-density lipoprotein cholesterol Lp-PLA2 = lipoprotein-associated phospholipase A2 MACE = major cardiovascular events MESA = Multi-Ethnic Study of Atherosclerosis MetS = metabolic syndrome MI = myocardial infarction MRFIT = Multiple Risk Factor Intervention Trial NCEP = National Cholesterol Education Program NHLBI = National Heart, Lung, and Blood Institute PCOS = polycystic ovary syndrome PCSK9 = proprotein convertase subtilisin/kexin type 9 Post CABG = Post Coronary Artery Bypass Graft trial PROSPER = Prospective Study of Pravastatin in the Elderly at Risk trial QALY = quality-adjusted life-year ROC = receiver-operator characteristic SOC = standard of care SHARP = Study of Heart and Renal Protection T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus TG = triglycerides TNT = Treating to New Targets trial VA-HIT = Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial VLDL-C = very low-density lipoprotein cholesterol WHI = Women's Health Initiative.

Association between venous thromboembolism events and fibrates: A comparative study

AIM

Previous studies highlighted a significant association between fibrates and venous thromboembolism (VTE) events in dyslipidemia diabetic patients. Studies in non-diabetic patients are divergent. The present study investigated the association between VTE events and fibrates in diabetic and non-diabetic patients.

METHODS

Two approaches were used: (1) a disproportionality analysis using the World health organization pharmacovigilance database VigiBase^® was used to evaluate the reporting odds-ratio (ROR) of fibrates for VTE events. Clinical and demographic characterizations of patients with fibrates-related VTE reports are described; (2) a case control-study was performed using the Caen university hospital medical information database between January 2008 and December 2012. Cases were dyslipidemia patients who were hospitalized for VTE without an evident provoking factor. Up to four controls per case were selected in dyslipidemia patients hospitalized for a non-VTE event. Controls were matched to cases by age, gender, date of hospitalization, diabetes, chronic kidney disease and hospitalization department. A multivariate conditional logistic regression was performed.

RESULTS

Disproportionality analysis: a total of 946 notifications were identified in VigiBase^® (32.9% of diabetic patients). Fibrates were significantly associated with an increased report of VTE (ROR 1.14, CI 1.07-1.22). Case-control study: a total of 163 cases (21.5% of diabetic patients) and 514 matched controls were recruited. Fibrates were significantly associated with a higher risk of VTE events that required hospitalization in multivariate analysis (odds-ratio (OR) 3.67, CI 1.82-7.37, P=0.0003). The association was only significant for fenofibrate in both approaches.

CONCLUSION

Fenofibrate was associated with a higher incidence of VTE events in diabetic and non-diabetic patients.

Starting with Rosuvastatin in Primary Hyperlipidemia—

The authors investigated the effects of rosuvastatin, beyond its lipid-lowering activity, on several nonlipid metabolic variables, along with its safety and tolerability, in patients treated for primary hyperlipidemia. Patients (n=55) with primary hyperlipidemia were open-label assigned to the recommended starting dose of rosuvastatin 10 mg/day, and serum metabolic variables were measured at baseline and after 8 and 20 weeks. Treatment with rosuvastatin produced significant reductions in total cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein B, nonhigh-density lipoprotein cholesterol (non HDL-C), and triglyceride concentrations, whereas HDL-C, apolipoprotein A-I, and lipoprotein(a) levels did not change significantly from baseline. The LDL-C treatment target was achieved in 71% of patients. No significant variations in renal function parameters (serum creatinine and creatinine clearance), insulin resistance estimates, and serum concentrations of uric acid, total homocysteine, vitamin B12, and folic acid were observed during the period of treatment. High-sensitivity C-reactive protein levels were significantly lowered by rosuvastatin therapy (median values, 3.1 vs 2.0 vs 1.9 mg/L, at 0, 8, and 20 weeks, respectively; p<0.0001). In conclusion, rosuvastatin at 10 mg/day is a highly effective, safe, and well-tolerated monotherapy option for patients with primary hyperlipidemia, with a favorable antiinflammatory potential and nondeteriorating effects on renal function.

The association between atorvastatin administration and plasma total homocysteine levels in renal transplant recipients

BACKGROUND

Statins improve prognosis in patients with coronary heart diseases by decreasing the incidence of vascular events. Excess prevalence of hyperhomocysteinemia, an independent risk factor of cardiovascular diseases, has been observed in stable renal transplant recipients (RTRs).

OBJECTIVES

The objective of our study was to evaluate the association between atorvastatin administration and plasma total homocysteine (tHcy) levels in RTRs.

PATIENTS AND METHODS

We performed a retrospective cross-sectional study in 148 cyclosporine A (CsA) treated stable RTRs. We compared tHcy level and other demographic and clinical variables in RTRs with and without atorvastatin.

RESULTS

58.1% of the 148 RTRs were treated with atorvastatin (20-40 mg/day). Mean tHcy levels were lower in patients treated with atorvastatin compared to nonusers (14.80 ± 5.13 µmol/l versus 16.95 ± 7.87 µmol/l, P = 0.04). The comparison of 85 patients treated with atorvastatin and 61 non-users revealed that those subjects with atorvastatin were older, with higher estimated creatinine clearance and elevated body mass index (BMI). They were more likely to have higher systolic blood pressure and CsA trough level (C0). The association between lower tHcy levels and atorvastatin use was confirmed in the multivariate regression model (P = 0.004). However tHcy levels were independently and negatively associated with serum folate (P = 0.0001) and vitamin B12 levels (P = 0.001) and positively with serum BUN (P = 0.001) and diastolic blood pressure (P = 0.024) as well.

CONCLUSIONS

These data support the association between lower tHcy levels and atorvastatin administration in RTRs. Further clinical trials are recommended to clarify homocysteine lowering effect of atorvastatin.

Intensive statin therapy, used alone or in combination with ezetimibe, improves homocysteine level and lipid peroxidation to a similar degree in patients with coronary artery diseases

BACKGROUND

Increase in the concentration of homocysteine is one of the risks of cardiovascular diseases. Coronary artery disease accompanied the increase of LDL cholesterol level and hipolipemic drugs are used in such treatments. Also these drugs have pleiotropic effects, which are not greatly known. The aim of that study is to compare the effect of three different hipolipemic therapies (rosuvastatin 15mg/d; atorvastatin 40mg/d; atorvastatin+ezetymibe 10mg/d+10mg/d) depending upon the concentration of homocysteine and lipid peroxidation in plasma of CAD patients with non-target LDL-cholesterol level.

METHODS AND RESULTS

The study involved 30 healthy subjects as well as 30 patients with angiographically confirmed coronary artery disease who despite at least 6 months hypolipidemic treatment did not achieve LDL-C <70mg/dl. The following parameters studied included homocysteine level, lipid peroxidation in plasma and lipidogram parameters. Our study showed increase of homocysteine level, lipid peroxidation in plasma, LDL-C concentration and total cholesterol level. After six months therapy, the following changes were observed in comparison to the values before therapy: decrease of homocysteine level in plasma - R15 20%, A40 26% and A+E 28%; decrease of lipid peroxidation in plasma - R15 31%, A40 27% and A+E 32%; decrease of LDL-C cholesterol level - R15 18%; A40 17% and A+E 33% and decrease of total cholesterol level - R15 9%, A40 15% and A+E 17%.

CONCLUSION

Our results suggest that intensive lipid-lowering therapy has a beneficial effect on certain parameters of the blood of CAD patients.

Use of Fibrates Monotherapy in People with Diabetes and High Cardiovascular Risk in Primary Care: A French Nationwide Cohort Study Based on National Administrative Databases

Background and Aim

According to guidelines, diabetic patients with high cardiovascular risk should receive a statin. Despite this consensus, fibrate monotherapy is commonly used in this population. We assessed the frequency and clinical consequences of the use of fibrates for primary prevention in patients with diabetes and high cardiovascular risk.

Design

Retrospective cohort study based on nationwide data from the medical and administrative databases of French national health insurance systems (07/01/08-12/31/09) with a follow-up of up to 30 months.

Methods

Lipid-lowering drug-naive diabetic patients initiating fibrate or statin monotherapy were identified. Patients at high cardiovascular risk were then selected: patients with a diagnosis of diabetes and hypertension, and >50 (men) or 60 (women), but with no history of cardiovascular events. The composite endpoint comprised myocardial infarction, stroke, amputation, or death.

Results

Of the 31,652 patients enrolled, 4,058 (12.8%) received a fibrate. Age- and gender-adjusted annual event rates were 2.42% (fibrates) and 2.21% (statins). The proportionality assumption required for the Cox model was not met for the fibrate/statin variable. A multivariate model including all predictors was therefore calculated by dividing data into two time periods, allowing Hazard Ratios to be calculated before (HR_<540) and after 540 days (HR_>540) of follow-up. Multivariate analyses showed that fibrates were associated with an increased risk for the endpoint after 540 days: HR_<540 = 0.95 (95% CI: 0.78–1.16) and HR_>540 = 1.73 (1.28–2.32).

Conclusion

Fibrate monotherapy is commonly prescribed in diabetic patients with high cardiovascular risk and is associated with poorer outcomes compared to statin therapy.

Effect of simvastatin on plasma homocysteine levels and its modification by MTHFR C677T polymorphism in Chinese patients with primary hyperlipidemia

OBJECTIVE

We investigate the effect of simvastatin on plasma homocysteine (Hcy) levels and whether genetic factor affects the effect of simvastatin.

METHODS

A total of 338 patients with hyperlipidemia were enrolled. Simvastatin was orally administered at a dose of 20 mg/day for 8 weeks. Plasma Hcy levels were measured by high-performance liquid chromatography at baseline and after 8 weeks of treatment. Genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism was performed by TaqMan probe technique.

RESULTS

Serum total Hcy levels were positively correlated with serum creatinine (r = 0.332, P < 0.001). Among total subjects, simvastatin treatment resulted in a significant reduction in serum Hcy levels after 8 weeks (-0.37 ± 2.21 μmol/L, P = 0.003), and this effect was dependent on the initial levels of serum Hcy. The individuals with 677TT genotype had a significantly higher baseline Hcy level and a greater change in Hcy levels. After stratification by body mass index (BMI), we observed a significant increase in Hcy levels among the TT genotype group in adjusted model (beta±SE: 2.64 ± 0.84 μmol/L; P = 0.002) among patients with BMI ≥ 25 (kg/m(2) ).

CONCLUSIONS

Simvastatin can cause a marked decrease in plasma Hcy levels. MTHFR C677T genetic variant contributes to simvastatin's effects among Chinese subjects with primary hyperlipidemia.

Effect of pharmacological treatments for diabetes on homocysteine

Hyperhomocysteinemia is a well-established risk factor for cardiovascular disease. The association of hyperhomocysteinemia with diabetes mellitus is complex and may explain some of the risk of CVD in diabetics not explained by traditional risk factors. Both modifiable and non-modifiable factors interact with homocysteine metabolism and determine the plasma homocysteine concentrations. These include genetic abnormalities, age, sex, and various nutritional and hormonal determinants, all of which play a role in atherosclerosis and accelerated peripheral and cardio-vascular disease (CVD). Several medications modulate homocysteine metabolism and hence may play a role in the pathogenesis of CVD. Changes in renal function and interference with the homocysteine metabolism account for some of these drug effects. While a few of these drugs raise plasma homocysteine concentrations, others are beneficial and may counter some of the deleterious effects of hyperhomocysteinemia. Treatment of hyperhomocysteinemia with vitamins lowers plasma homocysteine concentrations and also reverses many of these drug effects. Little data is available on the effect of this intervention on cardiovascular outcomes. This review briefly outlines the effect of various medications used in the management of type 2 diabetes mellitus and metabolic syndrome.

Effect of lovastatin therapy and withdrawal on serum uric acid level in people with type 2 diabetic nephropathy

BACKGROUND/AIM

A high uric acid (UA) level is demonstrated as a major risk factor of nephropathy and cardiovascular events in people with type 2 diabetes (T2D). This study aimed to evaluate the lovastatin effect on serum UA levels in people with type 2 diabetic nephropathy (T2DN).

METHODS

Thirty patients completed the study course, out of 38 adult male patients with T2DN who were initially enrolled. Lovastatin, 20 mg/d, was administered for 90 days. Afterwards, lovastatin was withdrawn for the next 30 days. Blood samples were obtained at baseline, after 45 and 90 days of intervention, and 30 days after the withdrawal of lovastatin. The serum level of UA was assessed by the uricase/PAP method. The lipid profile and high-sensitivity C-reactive protein (hs-CRP) were determined using commercial reagents and the ELISA method.

RESULTS

After 90 days of lovastatin intervention, cholesterol (Chol) and low-density lipoprotein cholesterol (LDL-C) levels significantly decreased and the high-density lipoprotein cholesterol (HDL-C) level increased significantly, despite the unchanged level of triglyceride (TG). After withdrawal, Chol, TG, and LDL-C levels were significantly increased, without any change in the HDL-C level. The baseline serum UA level was 5.94 ± 2.02 mg/dL and not changed after the intervention (5.95 ± 2.21 mg/dL; p = 0.969) and withdrawal period (5.80 ± 1.51 mg/dL; p = 0.647). The changes of serum UA levels were not correlated with the changes of serum hs-CRP levels, both after intervention and withdrawal (p = 0.963 & p = 0.835).

CONCLUSIONS

Lovastatin does not have any effect on the serum UA level in people with T2DN. There is no correlation between the anti-lipidemic and anti-inflammatory effects of lovastatin and its effect on serum UA.

Effect of a reduction in uric acid on renal outcomes during losartan treatment: a post hoc analysis of the reduction of endpoints in non-insulin-dependent diabetes mellitus with the Angiotensin II Antagonist Losartan Trial

Emerging data show that increased serum uric acid (SUA) concentration is an independent risk factor for end-stage renal disease. Treatment with the antihypertensive drug losartan lowers SUA. Whether reductions in SUA during losartan therapy are associated with renoprotection is unclear. We therefore tested this hypothesis. In a post hoc analysis of 1342 patients with type 2 diabetes mellitus and nephropathy participating in the Reduction of Endpoints in Non-Insulin-Dependent Diabetes Mellitus With the Angiotensin II Antagonist Losartan Trial, we determined the relationship between month 6 change in SUA and renal endpoints, defined as a doubling of serum creatinine or end-stage renal disease. Baseline SUA was 6.7 mg/dL in placebo and losartan-treated subjects. During the first 6 months, losartan lowered SUA by -0.16 mg/dL (95% CI: -0.30 to -0.01; P=0.031) as compared with placebo. The risk of renal events was decreased by 6% (95% CI: 10% to 3%) per 0.5-mg/dL decrement in SUA during the first 6 months. This effect was independent of other risk markers, including estimate glomerular filtration rate and albuminuria. Adjustment of the overall treatment effects for SUA attenuated losartan's renoprotective effect from 22% (95% CI: 6% to 35%) to 17% (95% CI: 1% to 31%), suggesting that approximately one fifth of losartan's renoprotective effect could be attributed to its effect on SUA. Losartan lowers SUA levels compared with placebo treatment in patients with type 2 diabetes mellitus and nephropathy. The degree of reduction in SUA is subsequently associated with the degree in long-term renal risk reduction and explains part of losartan's renoprotective effect. These findings support the view that SUA may be a modifiable risk factor for renal disease.

Niacin and fibrates in atherogenic dyslipidemia: pharmacotherapy to reduce cardiovascular risk

Although statin therapy represents a cornerstone of cardiovascular disease (CVD) prevention, a major residual CVD risk (60-70% of total relative risk) remains, attributable to both modifiable and non-modifiable risk factors. Among the former, low levels of HDL-C together with elevated triglyceride (TG)-rich lipoproteins and their remnants represent major therapeutic targets. The current pandemic of obesity, metabolic syndrome, and type 2 diabetes is intimately associated with an atherogenic dyslipidemic phenotype featuring low HDL-C combined with elevated TG-rich lipoproteins and small dense LDL. In this context, there is renewed interest in pharmacotherapeutic strategies involving niacin and fibrates in monotherapy and in association with statins. This comprehensive, critical review of available data in dyslipidemic subjects indicates that niacin is more efficacious in raising HDL-C than fibrates, whereas niacin and fibrates reduce TG-rich lipoproteins and LDL comparably. Niacin is distinguished by its unique capacity to effectively lower Lp(a) levels. Several studies have demonstrated anti-atherosclerotic action for both niacin and fibrates. In contrast with statin therapy, the clinical benefit of fibrates appears limited to reduction of nonfatal myocardial infarction, whereas niacin (frequently associated with statins and/or other agents) exerts benefit across a wider range of cardiovascular endpoints in studies involving limited patient numbers. Clearly the future treatment of atherogenic dyslipidemias involving the lipid triad, as exemplified by the occurrence of the mixed dyslipidemic phenotype in metabolic syndrome, type 2 diabetes, renal, and auto-immune diseases, requires integrated pharmacotherapy targeted not only to proatherogenic particles, notably VLDL, IDL, LDL, and Lp(a), but also to atheroprotective HDL.

Beneficial effects of raloxifene and atorvastatin on serum lipids and HDL phospholipids levels of postmenopausal women

Selective oestrogen receptor modulators (raloxifene) and statins (atorvastatin) have been shown to reduce the risk of cardiovascular disease associated with the postmenopausal status. Their beneficial effects may be mediated partly by favourable changes in serum lipids and particular on HDL phospholipid composition. In the present study, individual administration of either raloxifene (Group A) or atorvastatin (Group B) or both (Group C) was compared for a period of 3 months and their effects on total lipids and HDL phospholipids were evaluated. The combined treatment of raloxifene and atorvastatin resulted in profound changes in the majority of serum lipids, including a significant reduction in total cholesterol and triglycerides (P<0.001), a rise in total phospholipids (P<0.01) and a reduction in LDL-C and Apo B levels (P<0.001). Furthermore, Apo A-I was elevated (P<0.001) whereas total HDL phospholipids were significantly increased (P<0.05). Specifically, HDL phosphatidylcholine levels were markedly increased (P<0.001) and HDL lysophosphatidylcholine, sphingomyelin and phosphatidylinositol levels were reduced (P<0.05). A further attempt to evaluate each treatment group was performed and the significance of these results is discussed.

Treatment of hyperlipidaemia with fenofibrate and related fibrates

BACKGROUND

Fenofibrate is the most widely used fibrate. Its efficacy and tolerability in the treatment of hypertriglyceridaemia and combined hyperlipidaemia have been demonstrated in several clinical trials.

OBJECTIVE

To review the pharmacology, lipid-lowering and extra-lipid effects of fenofibrate and to preview ABT-335, an investigational new fenofibric acid molecule.

RESULTS

The effects of fenofibrate are mediated through the active metabolite fenofibric acid, and are described in detail in the paper. ABT-335 is a salt of fenofibric acid and, unlike fenofibrate, does not require first pass metabolism to the active moiety. ABT-335 is being developed for combination use with statins, and has recently completed three large Phase III randomised controlled trials in which the efficacy and safety of ABT-335 in combination with the three most commonly prescribed statins, atorvastatin, simvastatin and rosuvastatin, was evaluated in patients with mixed dyslipidaemia.

CONCLUSION

ABT-335 in combination with statins may provide a safe and efficacious treatment modality that enables achievement of several therapeutic goals in patients with mixed dyslipidaemia who have high cardiovascular risk.

Comparative effects of atorvastatin and simvastatin on the plasma total homocysteine levels in women with polycystic ovary syndrome: a prospective randomized study

OBJECTIVE

To test the hypothesis that statins improve hyperhomocysteinemia in women with polycystic ovary syndrome (PCOS).

DESIGN

A prospective randomized study.

SETTING

University Hospital.

PATIENT(S)

Fifty-two women with PCOS and 52 women matched for age and body mass index as controls.

INTERVENTION(S)

Patients were randomly divided into two groups for treatment: group 1, atorvastatin, 20 mg daily (n = 26), and group 2, simvastatin, 20 mg daily (n = 26). Blood samples were obtained before and after treatment.

MAIN OUTCOME MEASURE(S)

Serum homocysteine levels.

RESULT(S)

After 12 weeks of treatment, serum homocysteine levels in group 1 had decreased from 14.3 +/- 2.9 to 10.6 +/- 1.7 micromol/L; in group 2, the levels decreased from 13.6 +/- 2.1 to 11.1 +/- 1.9 micromol/L. Both two groups, free testosterone and total testosterone declined statistically significantly (38.3% and 36.5%; and 40.6% and 46.0%, respectively). In group 1, vitamin B(12) increased from 362.1 +/- 107 to 478.7 +/- 267 pg/mL; in group 2, it increased from 391.3 +/- 107 to 466 +/- 211 pg/mL, but the change did not reach statistical significance. There was a considerable decline in the homeostatic model assessment index in group 1 (40.0% to 32.1%).

CONCLUSION(S)

Treatment with statins in women with PCOS leads to decreases in serum homocysteine levels.

Is There a Role for Fibrates in the Management of Dyslipidemia in the Metabolic Syndrome?

The outcomes of fibrate trials have varied: positive with gemfibrozil in the primary prevention Helsinki Heart Study and the secondary prevention VA-HIT trial; positive with reservations in the primary prevention WHO trial (clofibrate); and mixed with bezafibrate in the secondary prevention BIP study and with fenofibrate in the combined primary and secondary prevention FIELD study. Overall, the mixed results, combined with potential for adverse effects when given in combination with statins, have limited the use of these fibrates as cardioprotective agents. However, post hoc analyses of several of the fibrate studies have shown that people with features of the metabolic syndrome, particularly overweight people with high plasma triglyceride levels and low levels of HDL cholesterol, derive a disproportionately large reduction in cardiovascular events when treated with these agents. Thus, there is a strong case for the use of a fibrate to reduce the cardiovascular risk in overweight people with high triglyceride and low HDL-C. However, it should be noted that such people also have their cardiovascular risk reduced by statin therapy. It remains to be determined whether the combination of a fibrate plus statin reduces the risk beyond that achieved with a statin alone.

Coronary reactivity, homocysteine and methylenetetrahydrofolate reductase gene variation in young men during pravastatin therapy

High plasma homocysteine (Hcy) has been linked to impaired endothelial function. We investigated whether treatment with pravastatin affects the Hcy levels. Moreover, we studied whether the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism affects coronary vasomotion at baseline and during the treatment with pravastatin. Fifty-one healthy, mildly hypercholesterolemic men (mean age 35+/-4 years) attended this randomised, double-blind, placebo-controlled study. The volunteers were randomised into groups with 6-month treatment with pravastatin (40 mg/day, n=25) or placebo (n=26). Coronary blood flow measurements with positron emission tomography at rest and during adenosine infusion as well as biochemical analyses were done at baseline and at the end of the treatment period. The Hcy concentration decreased significantly during the pravastatin therapy (-0.81+/-1.46 micromol/l, p=0.01), but not during placebo (0.02+/-2.39 micromol/l, p=0.97). The MTHFR polymorphism did not affect the Hcy concentration or coronary flow indices. Neither did the MTHFR polymorphism modulate the effects of pravastatin on coronary vasomotion. In conclusion, a 6-month therapy with pravastatin decreases Hcy concentration in Finnish healthy young men. The MTHFR genotype is neither a determinant of baseline coronary flow indices nor does it modulate the effect of pravastatin on coronary reactivity.

Homocysteine and cardiovascular disease: a review of the evidence

Elevated homocysteine (HCY) levels can be caused by a number of factors, including folate and B-vitamin deficiency, pre-existing atherosclerotic disease, diabetes and various drugs. Epidemiological evidence, as well as data from retrospective and prospective studies, supports an association between elevated HCY levels and increased risk of cardiovascular disease (CVD). However, whether lowering HCY levels by administration of folate and vitamins B6 and B12 is associated with any significant decrease in vascular risk remains the subject of ongoing debate. Although the major studies that have reported to date show that vitamin supplementation was associated with a decrease in HCY levels, this failed to have any significant effect on cardiovascular risk. Furthermore, although some lipid-modifying treatments have been shown to increase HCY levels, there is no evidence that this attenuates or compromises the beneficial effects of such treatments on cardiovascular risk. Taken together, these data suggest that HCY is a marker, rather than a cause, of CVD and therefore do not provide support for routine screening for and treatment of elevated HCY to prevent CVD. Data from ongoing clinical trials are awaited to clarify this issue.

Effects of atorvastatin therapy on hypercholesterolemic rabbits with respect to oxidative stress, nitric oxide pathway and homocysteine

Hypercholesterolemia is characterized with changes in lipid profile, nitric oxide pathway and oxidative stress markers. This study is designed to evaluate the effects of hypercholesterolemic diet and atorvastatin therapy on oxidative stress, lipid peroxide and thiobarbituric acid reactive substances (TBARS), NO pathway markers, nitric oxide(NO) and asymmetric dimethylarginine (ADMA), homocysteine, and paraoxonase activity (PON1) in rabbits. Twenty rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into 2 groups on the fourth week of the hypercholesterolemic diet. First group was fed with high-cholesterol diet alone, whereas the second group with the same cholesterol diet plus atorvastatin (0.3 mg/kg/day) for 4 weeks. High-cholesterol diet increased total cholesterol, low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), ADMA, TBARS and lipid peroxide levels and reduced PON1 activity and NO levels in rabbits. Four weeks of atorvastatin therapy significantly increased HDL-C, PON1 activity and reduced LDL-C, TBARS and lipid peroxide concentrations. Atorvastatin therapy is beneficial in decreasing oxidative stress related with hypercholesterolemia, mainly affecting lipid profile and PON1 activity.

Safety considerations with fibrate therapy

Fibrates are an important class of drugs for the management of dyslipidemia. This class of drugs is generally well tolerated but is infrequently associated with several safety issues. Fibrates, most likely by an effect mediated by peroxisome proliferator-activated receptor-alpha, may reversibly increase creatinine and homocysteine but are not associated with an increased risk for renal failure in clinical trials. Fibrates are associated with a slightly increased risk (<1.0%) for myopathy, cholelithiasis, and venous thrombosis. In clinical trials, patients without elevated triglycerides and/or low high-density lipoprotein cholesterol (HDL) levels, fibrates are associated with an increase in noncardiovascular mortality. In combination with statins, gemfibrozil generally should be avoided. The preferred option is fenofibrate, which is not associated with an inhibition of statin metabolism. Clinicians are advised to measure serum creatinine before fibrate use and adjust the dose accordingly for renal impairment. Routine monitoring of creatinine is not required, but if a patient has a clinically important increase in creatinine, and other potential causes of creatinine increase have been excluded, consideration should be given to discontinuing fibrate therapy or reducing the dose.

Uric acid and xanthine oxidase: future therapeutic targets in the prevention of cardiovascular disease?

Serum uric acid may be an independent risk factor for cardiovascular disease. This review examines this association, potential mechanisms, and explores whether strategies to reduce uric acid will improve outcomes. The recent studies of xanthine oxidase inhibition are given particular focus. Epidemiological evidence supports the theory that uric acid is an independent risk factor for cardiovascular disease. Recent studies of losartan, atorvastatin and fenofibrate suggest that uric acid reduction contributes to the risk reduction offered by these therapies. Several small studies of xanthine oxidase inhibition have shown improvements in measures of cardiovascular function of a similar magnitude to that of other proven preventative treatments. These trial data and the convincing epidemiological evidence mandate that large clinical trials of uric acid-lowering strategies are performed in patients with or at high risk of cardiovascular disease. If such approaches are shown to be effective in reducing cardiovascular events, they would represent a novel and cost-effective preventative approach.

New developments in clinically relevant mechanisms and treatment of hyperuricemia

The prevalence of gout has increased markedly in the United States in the past two decades, and new treatments for hyperuricemia are being developed. Recent molecular identification of urate transporter-1 (URAT1) as the central mediator of renal urate reabsorption has provided novel understanding of the pathogenesis of hyperuricemia, and the target site for current and possibly future primary uricosuric agents. Recent studies have also highlighted uricosuric effects of several drugs (losartan, atorvastatin, fenofibrate) that are prescribed for primary indications other than hyperuricemia. The niche of these agents in current management of hyperuricemia is discussed. We also review the ongoing development of recombinant uricase preparations and of novel xanthine oxidase inhibitors exemplified by febuxostat. These agents should provide novel options for patients with chronic, refractory gout and hyperuricemia, particularly in association with allopurinol hypersensitivity and renal insufficiency.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.

The Effect of Hormone Replacement Therapy and Simvastatin on Plasma Homocysteine

BACKGROUND

Homocysteine may be an independent risk factor for coronary artery disease (CAD), and the risk is at least as strong for women as for men. Homocysteine levels are lower in women compared with men, and homocysteine is lower during pregnancy and higher during menopause.

PURPOSE

To investigate the effects of hormone replacement therapy (HRT), simvastatin, and their combination on plasma homocysteine levels, we treated 16 postmenopausal, hypercholesterolemic women with CAD with HRT (0.625 mg conjugated equine estrogens [CEE] combined continuously with 2.5 mg medroxyprogesterone), 20 mg simvastatin, and their combination in a randomized, placebo-controlled study. Each treatment period was 8 weeks long, with a 4-week washout interval. Plasma homocysteine levels were evaluated at the end of each treatment period.

RESULTS

Only HRT, alone and in combination with simvastatin, significantly reduced homocysteine levels compared with placebo (11.82 +/- 0.74 and 12.22 +/- 0.71 vs 13.58 +/- 0.83 micromol/L, respectively, p < 0.05). Simvastatin had no effect (13.02 +/- 0.94 micromol/L), and the combination therapy was not better that monotherapy with HRT.

CONCLUSIONS

Oral HRT reduces homocysteine plasma levels, whereas simvastatin has no effect. If confirmed by randomized, prospective studies with clinical end points, HRT may be considered for women with mild hypercholesterolemia and high homocysteine levels.

Hyperhomocysteinemia in central retinal vein occlusion in young adults

PURPOSE

Several investigators have tried to assess the role of hyperhomocysteinemia and the 677C-T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene as risk factors in retinal vein occlusion with contrasting results. Aim of the study is to investigate the correlation between increased homocysteine plasma level and the homozygosity for the 677C-T mutation in the gene MTHFR in patients aged under 50 years affected by central retinal vein occlusion (CRVO).

METHODS

Through a prospective, case-control study, 31 patients under 50 years of age and diagnosed with CRVO were compared with two control groups. The first control group (GROUP I) included 31 subjects matched for age, sex, laboratory tests and the main risk factors for atherosclerosis. The second control group (GROUP II) consisted of 31 volunteers matched only for age and sex.

RESULTS

The mean homocysteine plasma level was 10.60 micromol/l in patients, 10.39 micromol/l in GROUP I and 9.34 micromol/l in GROUP II. There was no statistically significant difference between mean homocysteine plasma level in cases and in GROUP I. Mean homocysteine plasma level was lower in GROUP II than in patients, and the difference was statistically significant. Homozygosity for the 677C-T mutation in the MTHFR was found in four patients (12.9%), in five controls in GROUP I (16.1%) and in four controls in GROUP II (12.9%).

CONCLUSION

Our results support first of all the hypothesis that the homocysteine plasma level is not a primary and independent risk factor for central retinal vein occlusion, but is more likely a marker of atherosclerosis and the consequence of other well-established risk factors. Second, the importance of the design of the study is highlighted, since the obtained results differed on the basis of the considered control group. This feature could contribute to explain the contradictory results previously reported in the literature.

Effects of statin treatment on uric acid homeostasis in patients with primary hyperlipidemia

BACKGROUND

Epidemiologic studies have shown that serum uric acid is a risk factor of coronary artery disease. In addition to fenofibrate, there is some evidence that atorvastatin may have a hypouricemic action, but the underlying mechanisms remain speculative.

METHODS

This randomized trial was conducted to investigate the effects of atorvastatin and simvastatin on uric acid homeostasis in patients treated for primary hyperlipidemia. A total of 180 patients were enrolled; patients were randomly assigned to 40 mg/d of either atorvastatin or simvastatin. Serum lipid and metabolic parameters were measured at baseline and at 6 and 12 weeks of treatment; random urine samples were simultaneously obtained for creatinine, sodium, and uric acid determinations.

RESULTS

Baseline serum uric acid levels correlated positively with the body mass index, serum insulin, creatinine, and triglyceride levels and inversely with serum HDL cholesterol levels. Both statins caused a favorable effect on lipids and a significant decrease in fibrinogen and high-sensitivity CRP levels. However, only atorvastatin reduced serum uric acid levels (from 5.6 +/- 1.7 to 4.9 +/- 1.5 mg/dL, P <.0001) by augmenting its urinary fractional excretion (from 10.4% +/- 7.9% to 12.0% +/- 7.4%, P <.01). In a multivariate logistic regression analysis, the reduction of uric acid levels was independently associated with baseline serum uric acid concentration but not to other variables, including lipid parameters (OR, 1.65; 95% CI, 1.14 to 2.40; P =.008).

CONCLUSIONS

Atorvastatin (but not simvastatin) significantly lowered serum uric acid levels. This result may be in favor of a preferable choice of atorvastatin for the treatment of hyperlipidemic patients presenting with hyperuricemia.

Effect of rosuvastatin on plasma levels of asymmetric dimethylarginine in patients with hypercholesterolemia

Elevated plasma levels of asymmetric dimethylarginine (ADMA) have been associated with attenuated endothelium-dependent vasodilation in hypercholesterolemic patients. However, whether lowering of plasma cholesterol concentration by hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) can reduce plasma ADMA levels is still not clear. This study was a multicenter, randomized, double-blind, placebo-controlled design including 46 patients with elevated low-density lipoprotein cholesterol levels. Patients were randomized into 2 groups: rosuvastatin 10 mg/day and placebo for 6 weeks. Plasma levels of ADMA, 8-isoprostane (as a marker of oxidative stress), homocysteine, and high-sensitivity C-reactive protein were measured at baseline and 6 weeks later. Endothelial function assessed by flow-mediated vasodilation of the brachial artery was performed in 11 patients in the rosuvastatin group and in 12 in the placebo group. Baseline characteristics of both groups were similar, and the plasma ADMA levels were significantly correlated with 8-isoprostane (r = 0.388, p = 0.008). After 6 weeks of treatment, plasma ADMA levels were significantly reduced in the rosuvastatin group (from 0.60 +/- 0.19 to 0.49 +/- 0.10 micromol/L, p <0.001). Increases in flow-mediated vasodilation were positively correlated with reductions in plasma levels of ADMA (p = 0.017) and low-density lipoprotein cholesterol (p <0.001). Thus, our findings suggest that treatment with rosuvastatin in patients with hypercholesterolemia may lead to a significant reduction in plasma ADMA levels, which appear to be related to the improvement in endothelial function by rosuvastatin.

Effect of statins versus untreated dyslipidemia on serum uric acid levels in patients with coronary heart disease: a subgroup analysis of the GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study

BACKGROUND

Little is known about the effect of dyslipidemia on serum uric acid (SUA) levels, and less is known about the effect of statin treatment on them. The GREek Atorvastatin and Coronary-heart-disease Evaluation study suggested that a mean atorvastatin dose of 24 mg/d achieves the National Cholesterol Educational Program treatment goals and significantly reduces morbidity and mortality in patients with coronary heart disease (CHD) in comparison to the usual care. Here, we report the time course of SUA levels in usual-care patients undertreated for their dyslipidemia (12% were administered statins) in comparison to structured-care patients treated with atorvastatin in the vast majority (98%).

METHODS

Mean on-study SUA levels (up to 48 months) were compared with those at baseline by using analyses of variance to assess differences over time within and between treatment groups. Cox multivariate analysis was used to investigate whether changes in SUA levels during the study were clinically relevant.

RESULTS

All patients had normal renal function at baseline; serum creatinine (SCr) levels less than 1.3 mg/dL (<115 micromol/L) and moderately elevated SUA levels (mean, 7.1 +/- 0.9 [SD] mg/dL [425 +/- 52 micromol/L]; upper normal limit, 7.0 mg/dL [415 micromol/L]). Usual-care patients (n = 800) showed an increase in SUA levels by 3.3% ( P < 0.0001). Structured-care patients (n = 800) had an 8.2% reduction in SUA levels ( P < 0.0001). In all patients not administered diuretics (n = 1,407), SUA level changes showed a positive correlation with changes in SCr levels ( r = 0.82; P < 0.0001) and an inverse correlation with estimated glomerular filtration rate ( r = -0.77; P < 0.0001). After adjustment for 19 predictors of all CHD-related events, Cox multivariate analysis involving backward stepwise logistic regression showed a hazard ratio (HR) of 0.89 (95% confidence interval [CI], 0.78 to 0.96; P = 0.03) with every 0.5-mg (30-micromol/L) reduction in SUA level, an HR of 0.76 (95% CI, 0.62 to 0.89; P = 0.001) with every 1-mg (60-micromol/L) reduction, an HR of 1.14 (95% CI, 1.03 to 1.27; P = 0.02) with every 0.5-mg increase, and an HR of 1.29 (95% CI, 1.17 to 1.43; P = 0.001) with every 1-mg increase in SUA levels.

CONCLUSION

Data suggest that SUA level is an independent predictor of CHD recurrent events. Atorvastatin treatment significantly reduces SUA levels in patients with CHD, thus offsetting an additional factor associated with CHD risk.

Hyperhomocysteinemia and the methylenetetrahydrofolate reductase 677C-T mutation in patients under 50 years of age affected by central retinal vein occlusion

PURPOSE

To investigate the correlation between increased homocysteine plasma levels and the homozygosity for the 677C-T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in patients aged under 50 years affected by central retinal vein occlusion (CRVO).

DESIGN

Prospective, case-control study.

PARTICIPANTS AND CONTROLS

Participants included 31 consecutive patients under 50 years and diagnosed with CRVO. Two controls per case were selected. The first control group (group I) included 31 individuals matched for age, gender, laboratory tests, and the main risk factors for atherosclerosis. The second control group (group II) consisted of 31 volunteers matched only for age and gender.

METHODS

Fasting (>10 hours) blood samples were obtained from patients and controls. Blood samples were obtained from patients within 1 week after the onset of the vaso-occlusive event. Molecular genetic analysis for the 677C-T mutation in the MTHFR gene was performed in patients and controls. A plasma homocysteine reading of >12 micromol/l was considered an increase.

MAIN OUTCOME MEASURES

The total homocysteine plasma level (determined by the high-performance liquid chromatography method with fluorescence detection) and molecular genetic analysis for the 677C-T mutation in the MTHFR gene in patients and controls.

RESULTS

Mean ages were 44.5 years in the group comprising the patients and 44.3 and 44.2 years, respectively, in groups I and II. Mean homocysteine plasma levels were 10.60 micromol/l in patients and 10.39 and 9.34 micromol/l, respectively, in groups I and II. There was no statistically significant difference between mean homocysteine plasma levels in patients and group I controls. In fact, the mean homocysteine plasma level was lower in group II than in patients, and the difference was statistically significant. Homozygosity for the 677C-T mutation in the MTHFR gene was found in 4 patients (12.9%), 5 controls in group I (16.1%), and 4 controls in group II (12.9%).

CONCLUSION

The results of the present investigation support the hypothesis that the homocysteine plasma level is not to be considered a primary and independent risk factor for CRVO, but is more likely a marker of atherosclerosis and the consequence of other well-established risk factors. Moreover, the importance of the study design is brought out, because the results we obtained differ on the basis of the considered control group. This feature may in part explain the contradictory results reported in the literature.

Fenofibrate Increases Homocystinemia Through a PPARα-Mediated Mechanism

Plasma homocysteine levels increase in humans treated with fibrates but the molecular mechanisms are unknown. The goal of the present study was to determine the mechanism of this increase using animal models. Firstly, an increase in homocysteine was observed in mice treated with fenofibrate irrespective of the genetic background C57BL/6 or SV129. Secondly, as the effect of fenofibrate on gene expression is mediated through activation of the peroxisome proliferator-activated receptor alpha (PPARalpha), a transcription factor belonging to the nuclear receptor family, it was determined whether the effect of fenofibrate on homocysteine levels were modulated through PPARalpha activation. Using PPARalpha-deficient mice, it was shown that the homocysteine increase after fenofibrate treatment was completely abolished in these animals. It can be concluded that fibrates increase homocystinemia through a PPARalpha-mediated mechanism and that mice constitute an animal model for analyzing the molecular mechanisms behind the homocysteine increase after fibrate therapy in dyslipidemic patients.

Fenofibrate-induced hyperhomocysteinemia may be prevented by folate co-administration

OBJECTIVES

Several prospective studies reported that fibrates might increase blood total homocysteine (tHcy) concentrations. Because of this adverse effect, elevated tHcy could potentially compromise the cardiovascular benefit resulting from lipid-lowering by fibrates. In our study we aimed to find out whether the folate co-administration would modify the fibrate-induced elevation of tHcy.

METHODS

Twenty-four volunteers (m 17, f 7; mean age 54.9 years) with total cholesterol > or =6 mmol/L and triglycerides less than 5 mmol/L, with normal blood pressure, normal blood glucose and without any pharmacotherapy and/or clinical vascular or metabolic disease, were included in an open, randomised, prospective, crossover study. We measured lipids, tHcy, folate, vitamin B12 and renal function markers after diet, after a 6-month administration of 200 mg of fenofibrate (3 months in monotherapy followed by 3 months in combination with 10 mg of folate) and further on after an identical period of fluvastatin administration (3 months of 40 mg followed by 3 months of 80 mg).

RESULTS

Fenofibrate in monotherapy, beside the expected lipid-lowering effect, increased tHcy from 10.0 to 14.2 microM/L ( p<0.001). Co-administration of folate decreased tHcy to 10.6 microM/L. In contrast, fluvastatin did not significantly influence the tHcy concentrations.

CONCLUSION

Co-administration of folate to fenofibrate therapy has the potential to reverse the fibrate-induced elevation of tHcy.

Comparative effects of atorvastatin, simvastatin, and fenofibrate on serum homocysteine levels in patients with primary hyperlipidemia

Hyperhomocysteinemia is regarded as an independent risk factor for cardiovascular disease. Lipid-lowering agents, such as fibrates, can modify homocysteine levels. However, less is known about the effect of statin therapy on homocysteine. The authors compared the effects of atorvastatin (40 mg/day), simvastatin (40 mg/day), and micronized fenofibrate (200 mg/day) on the serum concentrations of total homocysteine, vitamin B12, and folic acid in patients with primary hyperlipidemia. A total of 128 patients with primary hyperlipidemia (total cholesterol > 240 mg/dL and triglycerides < 350 mg/dL) were assigned to atorvastatin, simvastatin, or fenofibrate. Serum lipid and metabolic parameters were measured at baseline and at 6 and 12 weeks of treatment. Homocysteine correlated positively with serum creatinine and uric acid levels and inversely with serum folic acid levels. All treatment modalities reduced total, low-density lipoprotein (LDL) cholesterol, and triglyceride concentrations. High-density lipoprotein (HDL) cholesterol levels significantly increased only in the fenofibrate-treated patients (47.9 +/- 12.5 vs. 50.7 +/- 12.6 vs. 51.2 +/- 12.8 mg/dL, p < 0.01). Atorvastatin and fenofibrate treatment resulted in a significant reduction of serum uric acid levels (5.3 +/- 1.6 vs. 4.9 +/- 1.4 vs. 4.8 +/- 1.4 mg/dL, p < 0.0001 for atorvastatin; 5.6 +/- 1.6 vs. 4.3 +/- 1.4 vs. 4.4 +/- 1.4 mg/dL, p < 0.0001 for fenofibrate). Homocysteine levels were significantly increased only by fenofibrate (10.3 +/- 3.3 vs. 14.1 +/- 3.8 vs. 14.2 +/- 3.6 microU/L, p < 0.001) but did not change from baseline following statin treatment. Neither statins nor fenofibrate had any effect on serum vitamin B12 and folic acid levels. In contrast to fenofibrate, therapeutic dosages of atorvastatin and simvastatin have a neutral effect on serum homocysteine levels, which is in favor of their "cardioprotective" properties.

Effect of folic acid on fenofibrate-induced elevation of homocysteine and cysteine

BACKGROUND

An elevated total plasma homocysteine (tHcy) level is considered to be an independent risk factor for atherosclerosis. It has been reported that lipid-lowering therapy with fibric acid derivatives (fibrates) increases tHcy and total plasma cysteine (tCys) levels. The aim of this study was to determine whether therapy with folic acid, a potent tHcy-lowering agent, could modify the fenofibrate-induced elevation of plasma aminothiols.

METHODS

Patients with combined hyperlipidemia (n = 37) were randomized to receive 9 weeks of treatment with micronized fenofibrate 200 mg/day (F group) or fenofibrate 200 mg/day plus folic acid 10 mg/every other day (F+F group). tCys and tHcy levels were determined before and after the therapy with high performance liquid chromatography.

RESULTS

The tHcy level increased significantly in the F group by 51.3% and in the F+F group by 14.6% (between-group difference P =.001). Total plasma cysteine (tCys) increased similarly after both treatments (P =.72). The serum creatinine level increased in the F group by 20.7% and in F+F group only by 9.8% (P =.04). The increase of tHcy level in F group correlated with an increase of tCys and creatinine levels (r = 0.74 and 0.64, respectively). The effects on the lipid profile did not differ by treatment group.

CONCLUSIONS

Folic acid effectively reduces the fenofibrate-induced elevation of tHcy and creatinine, but it does not affect the elevation of the tCys. Folic acid has neutral effect on the lipid-lowering action of fenofibrate. Clinical efficacy of fenofibrate might be improved by folic acid coadministration.

Update on fenofibrate

Fenofibrate is a fibric acid derivative that has been marketed since the mid-1970's (1998 in the United States). Its active metabolite, fenofibric acid, is responsible for the primary pharmacodynamic effects of the drug: reductions in total plasma cholesterol, low density lipoprotein cholesterol, triglycerides, and very low-density lipoprotein concentrations and increases in high-density lipoprotein cholesterol and apolipoproteins AI and AII concentrations. These effects are mediated by activation of peroxisome proliferator-activated receptor-alpha (PPAR(alpha)). The drug has broad spectrum utility, with documented efficacy in Fredrickson types IIa, IIb, III, IV, and V hyperlipidemias. Fenofibrate is well tolerated, with digestive and musculoskeletal side effects similar to those of other fibrates. Results of the initial cardiovascular morbidity/mortality outcomes study with fenofibrate (known as DAIS [Diabetes Atherosclerosis Intervention Study]) were encouraging vis-à-vis slowing of atherosclerotic progression in the coronary vasculature of type II diabetics. The results of other ongoing outcome trials are eagerly awaited. These results will help to establish the overall place of fenofibrate in the hypolipidemic armamentarium.

Fenofibrate-induced hyperhomocysteinaemia: clinical implications and management

Fenofibrate is among the drugs of choice for treatment of hypertriglyceridaemia and low levels of high-density lipoprotein (HDL)-cholesterol, both recognised as risk factors for cardiovascular disease. Recently, a number of studies have shown an elevation of homocysteine levels with fenofibrate or bezafibrate therapy. Homocysteine is an atherogenic amino acid derived from the methionine cycle. At present, the underlying mechanism for this elevation has not been elucidated. While deterioration of vitamin status does not seem to be involved, impairment of renal function or changes in creatine metabolism are regarded as probable mechanisms. In patients not receiving lipid-lowering drugs, vitamin supplementation with folic acid and vitamin B12 effectively reduces the plasma homocysteine level. Two studies have shown that addition of folic acid or a vitamin combination to fenofibrate prevented most of the homocysteine increase associated with fenofibrate. Although the consequence of increasing homocysteine levels for cardiovascular risk has not been proven at present, it has to be considered that fenofibrate will be given for long-term treatment. Therefore, addition of folic acid and vitamin B12 to fenofibrate can be recommended to prevent the increase of homocysteine associated with fenofibrate, or treatment could be changed to gemfibrozil, which does not increase plasma homocysteine levels.

Effects of cytidine 5'-diphosphocholine on plasma homocysteine levels in rat

We have investigated the effects of cytidine 5'-diphosphocholine (CDP-choline) on total plasma homocysteine concentration in male Sprague-Dawley rats of 2 months of age (young rats) or 15 months of age (old rats). Oral administration of 0.35 or 1 g/kg of CDP-choline to young rats significantly increased homocysteine, by 19 and 47%, respectively (P<0.05) in plasma obtained 25 min after treatment. This effect was transient for the administration of 0.35 g/kg and increased up to 64% (P<0.05) after 150 min for the administration of 1 g/kg. However, treatment through a supplemented diet resulting in an average daily intake of 0.35 g/kg of CDP-choline for up to 60 days did not significantly alter homocysteine concentration. Old rats showed a significantly (P<0.05) lower homocysteine level (25%) than control young animals, even after 60 days of treatment with the supplemented diet. Thus, when rats are used in experimental studies on the beneficial effects of CDP-choline, it has to be considered that administration of high doses of CDP-choline will not affect the plasma levels of the risk factor homocysteine as long as the compound is not administered as a single bolus.

Comparison of gemfibrozil and fenofibrate in patients with dyslipidemic coronary heart disease

STUDY OBJECTIVE

To compare the lipid-lowering effects of gemfibrozil and fenofibrate in patients with dyslipidemic coronary heart disease.

DESIGN

Open label, fixed-dosage, retrospective-prospective, one-way crossover from gemfibrozil to fenofibrate.

SETTING

University-affiliated outpatient clinics.

PATIENTS

Eighty patients with coronary heart disease with a baseline low-density lipoprotein cholesterol (LDL) level above 130 mg/dl or a triglyceride level of 200 mg/dl or higher who had been receiving gemfibrozil 600 mg twice/day. Thirty-nine (49%) patients had received concomitant therapy with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) for a minimum of 9 months.

INTERVENTION

All patients received gemfibrozil 600 mg twice/day for at least 3 months before being switched to fenofibrate 201 mg/day. Patients receiving concomitant statin therapy before crossover continued the statin at the same dosage after crossover. Before crossover, a fasting lipid profile was determined and patients were queried about the side effects of lipid-lowering therapy. A repeat fasting lipid profile was obtained 12 weeks after the crossover.

MEASUREMENTS AND MAIN RESULTS

Patients were stratified into those receiving versus those not receiving concomitant statin therapy. In both of these groups, fenofibrate was associated with significantly greater reductions in total cholesterol, LDL, and triglycerides than gemfibrozil (all p < 0.001). In addition, fenofibrate was associated with a significantly greater increase in high-density lipoprotein cholesterol (HDL) than gemfibrozil (p < 0.001). No patients reported new-onset adverse effects after the crossover.

CONCLUSIONS

Compared with gemfibrozil, fenofibrate produced significantly greater reductions in total cholesterol, LDL, and triglycerides and significantly greater increases in HDL. These changes were evident in patients receiving and not receiving concomitant statin therapy.

Effect of ciprofibrate on lipoproteins, fibrinogen, renal function, and hepatic enzymes

AIM

The action of ciprofibrate in hypertriglyceridemic patients is well established. Not only is ciprofibrate able to alter the lipid profile, but it can also change the values of fibrinogen, C-reactive protein, creatinine, transaminases, gamma-glutamyl transpeptidase and serum alkaline phosphatase. However, previous studies focused on the effect of ciprofibrate in hypertriglyceridemic patients, leaving unanswered the question of whether ciprofibrate exerts the same effect on hyperlipidemic patients with normal triglyceride values. The aim of this study is to answer this question.

METHODS

In this randomized clinical trial, 64 men and women with elevated cholesterol or triglyceride levels were included. Two subgroups were formed according to triglyceride levels: one (36 patients) with elevated triglyceride levels (> 200 mg/dL [2.26 mmol/L]) and another (28 patients) with normal triglyceride levels (< 200 mg/dL [2.26 mmol/l]). After a 6-week period of step 1 diet according to the National Cholesterol Education Program, ciprofibrate (100 mg once daily) was administered for 16 weeks. Primary efficacy points were the changes of lipid parameters (total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides, apoproteins A1, B, E and lipoprotein [a], high sensitivity C reactive protein, fibrinogen, glucose, insulin, aspartate transaminase, alanine transaminase, gamma-glutamyl transpeptidase, alkaline phosphatase, urea and creatinine levels in a fasting blood sample before and after treatment with ciprofibrate.

RESULTS

The subgroup with triglyceride < 200 mg/dL (2.26 mmol/L): After the administration of ciprofibrate total cholesterol and low-density lipoprotein cholesterol were reduced by 15% (P < 0.001), and 19% (P < 0.001), respectively, while high-density lipoprotein cholesterol increased by 9% (P = 0.02). Apoproteins B and E levels were reduced by 21% (P < 0.001) and 11% (P = 0.002), respectively. Subgroup with triglyceride > 200 mg/dL (2.26 mmol/L): After the administration of ciprofibrate, no significant change in LDL cholesterol levels was observed. Total cholesterol levels were reduced by 15% (P < 0.001) and high-density lipoprotein cholesterol levels were increased by 13% (P = 0.004). Apoprotein B and apoprotein E levels were reduced by 16% (P < 0.001) and 30% (P < 0.001), respectively. Apoprotein-A1 levels were increased by 5% (P = 0.024). In the whole group of patients, the fibrinogen levels fell by 7% (P = 0.043), and the serum creatinine level increased by 10% (P < 0.001). This rise in serum creatinine was more pronounced in patients with low triglyceride levels (15% vs 5%, P = 0.009). Ciprofibrate decreased C-reactive protein levels by 26% in 44 patients who had C-reactive protein measurements (P < 0.001). gamma-glutamyl transpeptidase activity was similarly decreased (by approximately 40%) in both groups of patients. Alkaline phosphatase activity decreased in both groups, a reduction which was greater in hypertriglyceridemics (20% vs 10%, P = 0.004).

CONCLUSIONS

Ciprofibrate improved some of the vascular risk factors, such as total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apoproteins A1, B, and E, and fibrinogen levels in both hypertriglyceridemics and normotriglyceridemics. In addition, ciprofibrate raised the serum creatinine and improved the activity of the hepatic enzymes in the plasma in both patient subgroups.