Alterations of Paraoxonase and Platelet-Activating Factor Acetylhydrolase Activities in Patients on Peritoneal Dialysis

Objective

The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD.

Design

A cross-sectional study.

Setting

A university medical center.

Participants

56 PD patients of Caucasian origin and 86 matched controls were studied.

Measurements

In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined.

Results

The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH / total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found.

Conclusion

The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH / total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients.

2980The effect of monoclonal antibodies against PCSK9 on circulating CD34+ progenitor cells interactions with platelets in patients with familial hypercholesterolemia

Introduction

Platelets interact with circulating CD34+ progenitor cells inducing their differentiation into endothelial progenitor cells (EPCs) and further promoting EPC maturation into endothelial cells, an important step for endothelial regeneration and angiogenesis. PSCK9 is a serine protease that may not only play a crucial role in binding to the low density lipoprotein receptor (LDL-R) increasing its endosomal and lysosomal degradation thus inhibiting its recycling to the cell surface, leading to increasing LDL-cholesterol levels in plasma, but may also exhibit several, independent on LDL-R, activities on a plethora of cell types, including platelets.

Purpose

We investigated whether monoclonal antibodies (mabs) against PCSK9 could affect platelet interaction with CD34+ cells as well as their differentiation into EPCs, in patients with Familial Hypercholestorelemia (FH).

Patients and methods

Patients with FH (n=11, 8 men and 3 women, mean age 53±10 years) being under statin/ezetimibe therapy (40mg statin/ 10mg ezetimibe) participated in the study. Patients exhibited resisting high LDL-cholesterol levels, therefore following the existing guidelines, they received mab against PCSK9 (7 evolocumab, 140mg/ml and 4 alirocumab, 150mg/ml) every two weeks. Blood samples were drawn before and after 4 doses of the antibody i.e. after two months (Follow-up). In addition to the patients' serum lipid profile, the endothelial phenotype of CD34+ (membrane expression levels of KDR which is a receptor for VEGF and an endothelial phenotype marker) on CD34+ cells (CD34+-KDR+ cells) and the formation of platelet-CD34+ (CD61+-CD34+) and platelet-KDR+ (CD61+-KDR+) conjugates were also determined by flow cytometry on whole blood after dual labelling with anti-VEGFR-R2/KDR-PE, anti-CD61-PerCP and anti-CD34-FITC. The results were expressed as the %gated of CD34+-KDR+ cells, as well as CD61+-CD34+ and CD61+-KDR+ conjugates.

Results

The baseline LDL-cholesterol levels were significantly reduced from 172±43 mg/dl to 51±17 at follow-up, p=0.0001. Importantly, the formation of CD61+-CD34+ and CD61+-KDR+ conjugates were increased from baseline to follow-up (from 1.39±1.3 to 2.23±2.8, p=0.037) and (from 2.91±4.2 to 5.92±6.01, p=0.014), respectively. The membrane expression of KDR on CD34+ cells was also increased from 0.79±0.9 to 1.36±0.90, p=0.042, which reflects the increase in the CD34+ endothelial phenotype.

Conclusion

We show for the first time that the mabs against PCSK9, significantly increase the CD34+ endothelial phenotype in FH patients, which may at least partially attributed to the increase in the platelet interaction with CD34+ cells (platelet-CD34+ conjugates). The underlying mechanisms as well as the consequences of this effect at the clinical level for these patients are under investigation.

Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence

Several studies have shown that angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are useful in the treatment of hypertension, cardiovascular disease, chronic heart failure, and some types of nephropathy. In this context, dual renin-angiotensin system blockade with both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may be more effective than treatment with each agent alone. Many clinical trials have demonstrated the beneficial effect of this combined treatment on proteinuria, hypertension, heart failure, and cardiovascular events. Moreover, these studies demonstrated that dual renin-angiotensin system blockade is generally safe and well tolerated. Long-term studies are under way to confirm these effects and also investigate the effectiveness of dual reninangiotensin system blockade on cerebrovascular disease and prevention of type 2 diabetes mellitus. These studies are expected to define the optimal use of combination treatment in everyday clinical practice. This review considers the most important clinical trials that evaluated the effect of dual renin-angiotensin system blockade on blood pressure, heart failure, and renal function.

Comparison of switch to the highest dose of rosuvastatin vs. add-on nicotinic acid vs. add-on fenofibrate for mixed dyslipidaemia

BACKGROUND

Use of a statin at a standard dose may be insufficient for the treatment of mixed dyslipidaemia. Whether switch to the highest dose of rosuvastatin (40 mg) or add-on nicotinic acid (NA) or fenofibrate is more efficacious remains unknown.

PATIENTS AND METHODS

This was a prospective, randomised, open-label, blinded end-point (PROBE) study. We recruited 100 patients with mixed dyslipidaemia who were treated with a statin at a standard dose but had not achieved lipid targets. Patients were randomised to switch to the highest approved dose of rosuvastatin (40 mg), add-on extended release nicotinic acid (ER-NA)/l-aropiprant (LRPT) or to add-on micronised fenofibrate for 3 months. The primary end-point was the change in non-high-density lipoprotein cholesterol (non-HDL-C) levels.

RESULTS

Ninety patients completed the study. Non-HDL-C decreased in all groups (by 23, 24 and 7% in the rosuvastatin, ER-NA/LRPT and fenofibrate group, respectively, p < 0.01 for all compared with baseline and p < 0.01 for all compared with fenofibrate group). Low-density lipoprotein cholesterol (LDL-C) decreased by 23 and 19% in the rosuvastatin and ER-NA/LRPT group, respectively (p < 0.01 compared with baseline), but not in the add-on fenofibrate group. Add-on ER-NA/LRPT was associated with the greatest HDL-C increase, while add-on ER-NA/LRPT and add-on fenofibrate were associated with the greatest triglyceride decrease. Twenty-four per cent of patients initially randomised to add-on ER-NA/LRPT dropped out because of side effects.

CONCLUSIONS

In conclusion, switch to the highest dose of rosuvastatin and add-on ER-NA/LRPT may be better options compared with add-on fenofibrate for the management of patients with mixed dyslipidaemia not on treatment goals with a statin at a standard dose.

Lysis syndrome during therapy of visceral leishmaniasis

INTRODUCTION

Lysis syndrome is a constellation of metabolic disorders usually seen after the initiation of chemotherapy for rapidly proliferating malignancies (tumor lysis syndrome). Reported herein is a tumor lysis-like syndrome after the initiation of anti-infective therapy for visceral leishmaniasis.

PATIENTS AND METHODS

Ten consecutive patients with visceral leishmaniasis were administered liposomal amphotericin B. Levels of serum uric acid, phosphate, creatinine, blood urea nitrogen, potassium, calcium, and magnesium were evaluated prior to as well as 4 and 30 days following the initiation of treatment.

RESULTS

During the 4th post-treatment day significant increases in the levels of serum uric acid, phosphate, creatinine, and blood urea nitrogen were seen, while the levels of calcium, potassium, and magnesium were not significantly altered. Patients were treated by hydration, urine alkalization, and administration of allopurinol as needed. A recovery of metabolic abnormalities was recorded 1 month later, although some patients had evidence of residual injury.

CONCLUSION

A lysis syndrome may complicate the treatment of visceral leishmaniasis. Awareness of this complication can lead to the initiation of prophylactic treatment as well as to early recognition and management of this syndrome in susceptible patients.

Effects of thyroid dysfunction on lipid profile

Thyroid dysfunction has a great impact on lipids as well as a number of other cardiovascular risk factors. Hypothyroidism is relatively common and is associated with an unfavorable effect on lipids. Substitution therapy is beneficial for patients with overt hypothyroidism, improving lipid profile. However, whether subclinical hypothyroidism should be treated or not is a matter of debate. On the other hand, hyperthyroidism can be associated with acquired hypocholesterolemia or unexplained improvement of lipid profile. Overall, thyroid dysfunction should be taken into account when evaluating and treating dyslipidemic patients.

Aliskiren, a direct renin inhibitor, in clinical practice: a new approach in the treatment of hypertension

OBJECTIVE

Arterial hypertension is an important risk factor for the development and progression of cardiovascular disease (CVD). The renin angiotensin aldosterone system (RAAS) plays a crucial role in the pathophysiology of hypertension and associated complications. Direct renin inhibitors (DRIs) are novel antihypertensive drugs which inhibit the first step of RAAS. Aliskiren is the first orally active DRI approved as monotherapy or in combination with other antihypertensive agents for the treatment of hypertension.

SCOPE

This article reviews the efficacy and safety of aliskiren as monotherapy and in combination with other antihypertensive agents and comments on its potential role in clinical practice.

METHODS

Relevant articles were identified through a PubMed search (up to 17 August 2009).

FINDINGS

Aliskiren, used alone or in combination with other antihypertensive agents, has a favourable effect on blood pressure (BP). Specifically, aliskiren is equally effective with other RAAS inhibitors and probably superior to hydrochlorothiazide in the reduction of systolic and diastolic BP. The combination of aliskiren with other antihypertensive drugs seems to be an effective and safe therapeutic option. In addition, aliskiren may have favourable effects in terms of ameliorating several microvascular and macrovascular complications of hypertension and diabetes.

CONCLUSIONS

Aliskiren appears to be an effective and safe antihypertensive drug. Whether the BP lowering effect of aliskiren is associated with improvements in cardiovascular outcomes remains to be elucidated.

Fenofibrate in primary biliary cirrhosis: a pilot study

Background:

Most patients with primary biliary cirrhosis (PBC) are treated with ursodeoxycholic acid (UDCA); however, some do not respond fully. PBC is also associated with dyslipidemia, but a link with vascular risk has not been confirmed.

Methods and Results:

In this study we compared UDCA monotherapy with fenofibrate plus UDCA in PBC patients with incomplete biochemical response to UDCA monotherapy for ≥ 8 months. Ten patients (57.2±13.3 years old) with PBC and persistent elevations of liver enzymes after treatment with UDCA (600 mg/day) were randomized to continue UDCA (4 patients) or to receive micronized fenofibrate (200 mg/day) plus UDCA (6 patients) for 8 weeks. Significant reductions in total cholesterol, triglycerides and non-high density lipoprotein cholesterol were observed in the combination treatment group. The serum activities of alkaline phosphatase, gamma-glutamyl transpeptidase and alanine aminotranferase also decreased in this group compared with baseline (-32.6%; p=0.012, -44%; p=0.031 and -16.9%; p=0.029, respectively). In contrast, no significant alterations in liver enzymes or lipid profile were observed in patients who continued UDCA monotherapy. The changes in the lipid and enzyme variables differed significantly (p<0.03) between the 2 groups. Fenofibrate was well tolerated.

Conclusions:

The administration of fenofibrate plus UDCA seems to be safe and may improve lipid and liver indices in patients with PBC who do not respond fully to UDCA monotherapy. Whether the improved lipid profile translates into a decreased risk of vascular events remains to be established.

Drug combinations for dyslipidemia and obesity treatment in metabolic syndrome

Metabolic syndrome (MetS) is a cluster of risk factors, each one individually associated with increased cardiovascular disease risk. Treatment of all components of MetS is expected to result in reduced risk. Treatment of MetS mainly includes lifestyle changes. In addition, drug therapy may be considered, especially combinations of different drugs, in order to tackle all the features of MetS. We review the therapeutic strategies currently used for obesity and dyslipidemia treatment in patients with MetS, with a focus on drug combinations.

Persistence of an atherogenic lipid profile after treatment of acute infection with Brucella

Serum lipid changes during infection may be associated with atherogenesis. No data are available on the effect of Brucellosis on lipids. Lipid parameters were determined in 28 patients with Brucellosis on admission and 4 months following treatment and were compared with 24 matched controls. Fasting levels of total cholesterol (TC), HDL-cholesterol (HDL-C), triglycerides, apolipoproteins (Apo) A, B, E CII, and CIII, and oxidized LDL (oxLDL) were measured. Activities of serum cholesterol ester transfer protein (CETP), paraoxonase 1 (PON1), and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and levels of cytokines [interleukins (IL)-1beta, IL-6, and tumor necrosis factor (TNFa)] were also determined. On admission, patients compared with controls had 1) lower levels of TC, HDL-C, LDL-cholesterol (LDL-C), ApoB, ApoAI, and ApoCIII and higher LDL-C/HDL-C and ApoB/ApoAI ratios; 2) higher levels of IL-1b, IL-6, and TNFa; 3) similar ApoCII and oxLDL levels and Lp-PLA(2) activity, lower PON1, and higher CETP activity; and 4) higher small dense LDL-C concentration. Four months later, increases in TC, HDL-C, LDL-C, ApoB, ApoAI, and ApoCIII levels, ApoB/ApoAI ratio, and PON1 activity were noticed compared with baseline, whereas CETP activity decreased. LDL-C/HDL-C ratio, ApoCII, and oxLDL levels, Lp-PLA(2) activity, and small dense LDL-C concentration were not altered. Brucella infection is associated with an atherogenic lipid profile that is not fully restored 4 months following treatment.

How safe is the use of thiazolidinediones in clinical practice?

BACKGROUND

Thiazolidinediones (TZDs) are widely used antidiabetic drugs with proven efficacy regarding mainly surrogate markers of diabetes management. However, efficacy on surrogate markers may not always translate into benefits in clinical outcomes. Thiazolidinediones are usually well tolerated; however, their use may be associated with several adverse effects. The first TZD, troglitazone, was withdrawn from the market owing to serious hepatotoxicity. However, this does not seem to be the case with newer TZDs.

OBJECTIVE

The aim of the present review is to discuss the safety profile of this drug class.

METHODS

We searched PubMed up to July 2008 using relevant keywords.

CONCLUSIONS

Common side effects associated with TZDs include edema, weight gain, macular edema and heart failure. Moreover, they may cause hypoglycemia when combined with other antidiabetic drugs as well as decrease hematocrit and hemoglobin levels. Increased bone fracture risk is another TZD-related side effect. Thiazolidinediones tend to increase serum low density lipoprotein cholesterol levels, with rosiglitazone having a more pronounced effect compared with pioglitazone. Moreover, rosiglitazone increases low density lipoprotein particle concentration in contrast to pioglitazone where a decrease is observed. Rosiglitazone has been associated with an increase in myocardial infarction incidence. On the other hand, pioglitazone may reduce cardiovascular events. Overall, TZDs are valuable drugs for diabetes management but physicians should keep in mind that they are associated with several adverse events, the most prominent of which is heart failure.

Effect of rimonabant, micronised fenofibrate and their combination on cardiometabolic risk factors in overweight/obese patients: a pilot study

OBJECTIVE

To assess the effect of rimonabant, micronised fenofibrate and their combination on anthropometric and metabolic parameters in overweight/obese patients with dyslipidaemia.

METHODS

All patients (n = 30) received a hypocaloric diet ( approximately 600 kcal/day deficit) and were randomly allocated to receive open-label rimonabant (R) 20 mg/day (n = 10), micronised fenofibrate (F) 200 mg/day (n = 10) or rimonabant 20 mg/day plus fenofibrate 200 mg/day (RF) (n = 10). Anthropometric and metabolic parameters were assessed at baseline and 3 months after treatment initiation.

RESULTS

Compared with baseline similar significant reductions in body weight, body mass index and waist circumference were observed in the R (-6, -5 and -5%, respectively; p < 0.01) and RF group (-5% for all, p < 0.05), while improvements in these parameters were smaller in the F group (-2, -2.5 and -2%, respectively; p < 0.05). Triglycerides were reduced by 18% in the R group (p = NS), by 39% in the F group (p < 0.001) and by 46% in the RF group (p < 0.05). Importantly, combination treatment resulted in a 42% increase in high-density lipoprotein cholesterol (HDL-C) levels (p < 0.05), while HDL-C was not significantly altered in the two monotherapy groups. Subsequently, a more pronounced increase in apolipoprotein A-I (ApoA-I) levels (+25%) was observed in the RF group compared with changes in both monotherapy groups (p < 0.0001 vs R and p < 0.005 vs F group). Low-density lipoprotein cholesterol (LDL-C) levels were not significantly altered in any group. Apolipoprotein B (apoB) levels were reduced in all groups and this reduction was significantly more pronounced in the RF group (p < 0.05 vs baseline as well as p < 0.005 and p < 0.01 for RF vs R and F groups, respectively). ApoB/apoA-I ratio decreased by 3% with R (p = NS), by 18% with F (p < 0.05) and by 40% with RF treatment (p < 0.01). Total cholesterol to HDL-C ratio decreased by 20% with F (p < 0.0001) and by 33% with RF therapy (p < 0.005), while it was not significantly altered in R group.

CONCLUSION

The combination of rimonabant and fenofibrate may further improve metabolic parameters in overweight/obese patients with dyslipidaemia compared with each monotherapy. This improvement is particularly pronounced for HDL-C levels.

Effects of hormonal treatment on lipids in patients with cancer

Patients with malignant disease may need hormonal therapy as primary or adjuvant treatment or for palliation. Oestrogens usually decrease serum levels of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), increase high density lipoprotein cholesterol (HDL-C) concentration, but induce an elevation in serum triglyceride (TG) levels. Progestogens in the short-term decrease TC, LDL-C and HDL-C concentrations, and increase TG levels. In long-term treatment, progestogens usually have a small impact on lipid profile. Tamoxifen induces a decrease in TC and LDL-C levels, an increase in TG concentration, whereas either an increase, decrease or no change has been reported for HDL-C levels. Aromatase inhibitors induce an elevation, reduction or no change in lipid variables. These results depend mainly on the trial design, i.e. whether patients received prior treatment with tamoxifen or not and the duration of therapy. Gonadorelin analogues increase all lipid variables, but LDL-C alterations are usually non-significant. Anti-androgens usually decrease TC, LDL-C and HDL-C levels, whereas TG alterations vary. Information regarding the effects on lipid profile of somatostatin analogues is available almost exclusively in patients with acromegaly. In these patients somatostatin analogues usually induce no change or a decrease in TC and LDL-C levels, whereas they increase HDL-C and decrease TG serum concentrations. Oncologists should consider the lifestyle changes, and if needed hypolipidemic treatment, used to lower cardiovascular risk in non-cancer patients. Tamoxifen may rarely cause serious TG-related side effects, like acute pancreatitis.

Effects of sibutramine plus verapamil sustained release/trandolapril combination on blood pressure and metabolic variables in obese hypertensive patients

OBJECTIVE

The management of obese hypertensive subjects may require the administration of anti-obesity and antihypertensive drugs. Sibutramine use has raised concerns regarding a potential increase in subjects' blood pressure and heart rate. The primary end-points of this study were an evaluation of the effect of sibutramine together with a verapamil sustained release/trandolapril combination tablet versus verapamil sustained release/trandolapril alone on the blood pressure and heart rate in obese hypertensive patients.

RESEARCH DESIGN/METHODS

Patients received a low-fat low-calorie diet and were randomly allocated to open-label verapamil sustained release/trandolapril 180/2 mg (n = 26) or sibutramine 10 mg together with verapamil sustained release/trandolapril 180/2 mg (n = 28) daily for 6 months.

RESULTS

Significant reductions in the subjects' systolic blood pressure and diastolic blood pressure were observed in both groups (p < 0.01 versus baseline). At 6 months a greater fall in blood pressure was observed in the sibutramine/verapamil sustained release/trandolapril group compared with the verapamil sustained release/trandolapril group (systolic blood pressure 21.9 +/- 8.1 versus 15.9 +/- 12.3 mmHg and diastolic blood pressure 15.7 +/- 8.1 versus 9.1 +/- 9.9 mmHg) but this was only significant (p = 0.03) for diastolic blood pressure. The subjects' heart rate did not change significantly in any group. No significant sibutramine-associated attenuation of blood pressure reduction was observed during the study. The sibutramine/verapamil sustained release/trandolapril treatment resulted in significantly greater improvement in the subjects' anthropometric variables, homeostasis model assessment and lipid profiles compared with verapamil sustained release/trandolapril administration. The subjects' small dense low-density lipoprotein cholesterol, high-sensitivity C-reactive protein and visfatin plasma levels were only measured in the sibutramine/verapamil sustained release/trandolapril group (all decreased by p < 0.05 versus baseline).

CONCLUSIONS

The sibutramine/verapamil sustained release/trandolapril combination in obese hypertensive patients significantly reduced their blood pressure and improved their anthropometric and metabolic variables without affecting the heart rate.

Sibutramine-associated adverse effects: a practical guide for its safe use

Obesity is a multifactorial chronic disorder which comprises a serious health problem nowadays. The effective management of obesity is difficult in contemporary societies where abundance of hypercaloric food and sedentary lifestyle is the rule. Apart from lifestyle interventions, which include diet, exercise and behavioural treatment, weight-loss medications can also be used for the management of obesity. Sibutramine, a selective monoamine reuptake inhibitor, is a drug with established efficacy in sustained weight reduction and an overall favourable safety profile. However, its action on the sympathetic nervous system has linked sibutramine to blood pressure and heart rate elevations. These potentially adverse effects as well as other sibutramine-associated side effects and their possible underlying mechanisms are reviewed in the present article. Compelling evidence from the majority of data in the literature shows that sibutramine can be effectively used in conjunction with caloric restriction and exercise in obese patients. Hypertension, if adequately treated and frequently monitored, is not an absolute contraindication for the prescription of sibutramine.

The effects of orlistat and fenofibrate, alone or in combination, on high-density lipoprotein subfractions and pre-beta1-HDL levels in obese patients with metabolic syndrome

OBJECTIVE

We assessed the effect of orlistat and fenofibrate, alone or in combination, on plasma high-density lipoprotein (HDL) subfractions and plasma pre-beta1-HDL levels in overweight and obese subjects with metabolic syndrome (MetS).

METHODS

Patients (n = 89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200 mg/day (F group) or both (OF group) for 6 months. HDL subfractions were determined using a polyacrylamide gel tube electrophoresis method and pre-beta1-HDL levels using enzyme-linked immunoabsorbent assay.

RESULTS

We observed a significant change of high-density lipoprotein cholesterol (HDL-C) levels only in the F group (+3%, p < 0.05). Large HDL-C levels were significantly increased and small HDL-C levels were significantly reduced with O administration. In F group we observed a significant increase of small HDL-C levels. No significant change of large or small HDL-C levels was observed with combination treatment. We observed a significant increase of pre-beta1-HDL levels in all groups, which was significantly greater in OF group compared with O or F monotherapy.

CONCLUSION

OF combination increased the antiatherogenic pre-beta1-HDL levels in overweight and obese patients with MetS. Furthermore, OF combination counterbalanced the reduction of small HDL-C levels observed with orlistat monotherapy.

Fibrate-associated adverse effects beyond muscle and liver toxicity

Fibrate derivatives have a 40-year history in the management of dyslipidemia. Although this class of drugs is generally well tolerated, several safety issues have arisen from their use. In the present article we review the literature describing side effects associated with the use of fibrates except for those that are liver and muscle related. These effects are less well known but are clinically relevant.

Colesevelam hydrochloride in clinical practice: a new approach in the treatment of hypercholesterolaemia

OBJECTIVE

Hypercholesterolaemia is a major risk factor for atherosclerosis and coronary heart disease. Treatment with lipid lowering agents reduces the risk of vascular events. Colesevelam is a novel bile acid sequestrant (BAS) indicated for the treatment of hypercholesterolaemia, either as monotherapy or in combination with statins.

SCOPE

This article reviews the efficacy, tolerability and safety of colesevelam in clinical practice. The literature search was based on a PubMed search up to January 2008.

FINDINGS

Colesevelam, used alone or in combination with other hypolipidaemic agents (statins, ezetimibe and fenofibrate), has an overall favourable effect on lipid profile. Specifically, colesevelam reduces total and low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B levels and increases high-density lipoprotein cholesterol and apolipoprotein AI. However, colesevelam may slightly raise triglyceride levels. Colesevelam can improve glycaemic control in diabetic patients. Moreover, it may have anti-inflammatory properties, as it can reduce high sensitivity C-reactive protein concentration. Colesevelam almost lacks the intense side effects of previously used BASs, thus resulting in better patient compliance. However, the dose regimen consisting of up to 7 tablets/day and high cost may limit its use.

CONCLUSIONS

Colesevelam is a safe alternative for those intolerant to other lipid lowering medication. This BAS also provides an option for patients who do not reach their LDL-C goal despite treatment with a statin.

Absence of SLC22A12 gene mutations in Greek Caucasian patients with primary renal hypouricaemia

OBJECTIVE

Primary renal hypouricaemia is a hereditary clinical disorder characterized by increased renal urate clearance due to isolated renal tubular defect of uric acid transport. There have been only a few studies on primary renal hypouricaemia in Caucasian populations. Defects in the SLC22A12 gene, which encodes the renal urate transporter URAT1, have been reported to be related to the disease pathogenesis. This study was undertaken to elucidate whether SLC22A12 gene mutations are responsible for low serum uric acid levels in Greek people.

MATERIAL AND METHODS

Nine Greek Caucasian subjects with primary renal hypouricaemia were included in the study. All had serum uric acid less than 2.5 mg dL(-1) (0.14 mmol L(-1)), fractional excretion of uric acid more than 10% and no other known causes of hypouricaemia. Mutation analysis of the SLC22A12 gene was performed.

RESULTS

No mutation was found--only the previously reported silent polymorphism 1246T > C (His 42His) in exon 2 of the SLC22A12 gene.

CONCLUSIONS

No previously reported mutation of URAT1 was associated with primary renal hypouricaemia in Greek subjects.

Ezetimibe-associated adverse effects: what the clinician needs to know

OBJECTIVE

Ezetimibe is a relatively new lipid lowering agent, which is indicated for the treatment of primary hypercholesterolaemia, either as monotherapy or in combination with other hypolipidaemic drugs. The objective of the present article was to review the side effects attributed to ezetimibe administration and discuss their possible underlying mechanisms. Moreover, we aimed to comment on the possible drug interactions of ezetimibe and present current guidelines regarding its safe use.

METHODS

Relevant articles were identified through a PubMed search (up to June 2007).

RESULTS

Compelling evidence from the majority of the data reviewed here showed that adverse effects associated with ezetimibe use are few and mild without having been associated with serious clinical outcomes. In most studies ezetimibe has not been associated with increased rates of myopathy or rhabdomyolysis, whether used alone or in combination with statins, although there have been some case reports of myopathy attributed to this agent. Moreover, ezetimibe has been associated with mild elevations of liver transaminases, mainly in combination with a statin. Other side effects are extremely rare. It should be noted, however, there are no long-term safety data or outcome studies for ezetimibe yet.

CONCLUSIONS

Ezetimibe is a safe alternative option for hyperlipidaemic patients intolerant to other lipid lowering drugs as well as a beneficial supplementary agent for patients who do not reach the recommended serum cholesterol level with their current hypolipidaemic treatment. However, as is the case with all new medications, physicians should be alert to recognise adverse effects associated with ezetimibe and report them to regulatory authorities.

The effect of orlistat and fenofibrate, alone or in combination, on small dense LDL and lipoprotein-associated phospholipase A2 in obese patients with metabolic syndrome

BACKGROUND

Increased concentration of small dense LDL cholesterol (sdLDL-C) and activity of lipoprotein-associated phospholipase A2 (Lp-PLA(2)) are considered as emerging cardiovascular risk factors and are commonly encountered in subjects with metabolic syndrome (MetS).

OBJECTIVE

The primary endpoint of this study was the effect of orlistat and fenofibrate, alone or in combination, on Lp-PLA(2) activity and LDL phenotype in overweight and obese patients (body mass index>28 kg/m(2)) with MetS.

METHODS

Patients (n=89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200mg/day (F group) or both (OF group) for 6 months.

RESULTS

Significant reductions of sdLDL-C levels were observed in all treatment groups. Groups F and OF experienced a greater reduction in sdLDL-C levels (p<0.05) together with a greater increase in LDL particle diameter (p<0.05) compared with group O. Total plasma Lp-PLA(2) activity significantly decreased in all treatment groups. The reduction of Lp-PLA(2) was more pronounced with OF administration compared with each monotherapy (p<0.05).

CONCLUSION

Orlistat and fenofibrate exhibited favorable effects on Lp-PLA(2) activity and LDL phenotype in overweight and obese patients with MetS. Importantly, combination treatment had a more favorable effect on these risk factors.

Fibrinogen: a predictor of vascular disease

Raised plasma fibrinogen levels are associated with an increased risk of vascular events. This may be mediated by adverse effects of fibrinogen on plasma viscosity, coagulation, platelet activity, inflammation and atherogenesis. However, there is as yet no drug that specifically lowers plasma fibrinogen levels on a long-term basis. Thus, we do not have intervention trials demonstrating that lowering plasma fibrinogen levels will result in a decreased risk of vascular events. However, such a trial may never happen unless a specific agent is discovered or designed. Several drugs that are used in vascular disease prevention (e.g. lipid lowering agents and antihypertensives) may influence plasma fibrinogen levels. Whether such an additional effect accounts for variations in the benefit resulting from the use of different drugs within the same class remains to be established. The debate continues as to whether fibrinogen is just a marker of vascular risk or whether lowering its circulating levels will result in a significant decrease in clinically relevant endpoints. Whatever the case, the measurement of plasma fibrinogen levels is likely to provide a more comprehensive estimation of risk.

Do statins have an antiarrhythmic activity?

Sudden cardiac death, which is mainly associated with the presence of life-threatening ventricular arrhythmias, is a common 'killer' among patients with coronary artery disease. Moreover, atrial fibrillation is the most common arrhythmia encountered in the clinical practice. The beneficial effect of statins on cardiovascular morbidity and mortality is well-established, while the exact role of this class of drugs against arrhythmias remains unclear. This review discusses the effect of statin treatment on arrhythmias that are commonly seen in the clinical setting. The underlying pathophysiological mechanisms are also overviewed. Compelling evidence from the majority of the studies reviewed shows that statins exhibit a protective effect against the occurrence of ventricular arrhythmias and atrial fibrillation.

Analysis of antihypertensive effects of statins

Hypertension and hyperlipidemia, two powerful risk factors of cardiovascular disease (CVD), often coexist. Therefore, treatment should consider the beneficial properties of drugs used to treat either condition. Statins, the mainstay of lipid-lowering therapy, result in a significant clinical benefit both in primary and secondary CVD prevention. In addition to their hypolipidemic capacity, other properties may contribute to statin-induced benefits. Clinical and experimental evidence indicates that statins may modulate blood pressure (BP). The mechanisms by which statins reduce BP seem to be largely independent of their lipid effects. Although small, reductions in BP are possibly clinically relevant. Large landmark studies confirm that statins can reduce CVD risk in hypertensive patients. These findings suggest that statins could be prescribed as an adjunct in treating hypertension with dyslipidemia or even in patients with "normal" cholesterol levels. Whether the effect of statins on BP is accompanied by an additional decrease in clinical outcomes needs to be investigated in long-term, large-scale trials.

Different definitions of the metabolic syndrome and risk of first-ever acute ischaemic non-embolic stroke in elderly subjects

To investigate which of the three recently proposed definitions of the metabolic syndrome (MetS) is related to the excessive risk of ischaemic non-embolic stroke in elderly individuals, and thus may be more appropriate to implement in clinical practice. In a population-based case-control study of subjects aged older than 70 years (163 patients vs. 166 controls), we evaluated the association of first-ever acute ischaemic non-embolic stroke with the MetS defined by using recent definitions as proposed by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), the International Diabetes Federation (IDF) and the National Heart, Lung and Blood Institute/American Heart Association (NHLBI/AHA). By applying the NCEP ATP III, NHLBI/AHA and IDF definitions, the prevalence of MetS in the patient group was 46%, 57.1% and 69.9%, respectively, compared with 15.7%, 18.1% and 30.7% in the control group (p < 0.001 for all comparisons). After adjusting for multiple risk factors, the odds ratio (OR) for ischaemic stroke was 2.59 [95% confidence interval (CI): 1.24-5.42, p = 0.012] for NCEP ATP III-defined MetS and 3.18 (95% CI: 1.58-6.39, p = 0.001) for NHLBI/AHA-defined MetS. However, the association of IDF-defined MetS with ischaemic stroke was not significant (OR 1.18, 95% CI: 0.50-2.78, p = 0.71). The implementation of the IDF (unlike NCEP ATP III and NHLBI/AHA) MetS definition substantially increases the number of elderly subjects labelled as having MetS without contributing to the identification of those at high risk of stroke.

Statins and Solid Organ Transplantation

Dyslipidaemia is common in solid organ transplant recipients and its presence is associated with chronic rejection and accelerated atherosclerosis, leading to an increased prevalence of cardiovascular disease (CVD). CVD is a major cause of morbidity and mortality in transplant recipients. It is therefore of interest and clinical value to introduce agents that effectively and safely reduce the incidence of this outcome. In the present review we consider the potential benefits of statin administration in adults who have undergone solid organ (mainly renal, heart and liver) transplantation, as well as in paediatric transplant patients. We also briefly review the effects of combination therapy with ezetimibe and statins in this population. Overall, statins are efficient and safe drugs for the management of dyslipidaemias in transplant populations, and in most trials they had a beneficial effect on long-term survival rates, CVD events and rejection rates. The transplanted population is different from other patient groups, mostly due to concomitant immunosuppressive therapy. Statins, at an appropriate dosage, should be prescribed to dyslipidaemic transplanted patients but they should be closely monitored for adverse effects.

Statin-associated adverse effects beyond muscle and liver toxicity

Randomized controlled trials with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have consistently demonstrated significant reductions in cardiovascular morbidity and mortality. Statins are currently the most widely used drugs in many countries. The most important adverse effects are associated with muscle and liver toxicity. However, with increased use and dose of statins and their over-the-counter availability in some countries more cases of other rare side effects may be seen in clinical practice. In the present article we review the literature concerning the statin-related adverse effects other than muscle and liver injury and we provide insight into their clinical relevance and possible underlying mechanisms.

Statins: another class of antihypertensive agents?

The assessment of global cardiovascular risk is an essential step in the management of atherosclerotic disease prevention. Among the risk factors to be addressed are hypertension and hyperlipidaemia; these commonly coexist. A neutral or lipid-friendly antihypertensive agent is probably useful in the presence of lipid abnormalities. Similarly, statins have been shown to decrease cardiovascular risk in hypertensive patients. There is also experimental and clinical evidence that statins have blood pressure (BP)-lowering effects. In this review, we discuss the beneficial effects of statins on BP, and provide an overview of the underlying pathophysiology. We also consider the evidence justifying the use of statins in the management of hypertensive patients.

Could statins be useful in the treatment of patients with migraine?

Migraine is a common and disabling neurological disorder. Studies have shown that patients with migraine (especially those with typical aura with migraine) have an unfavorable cardiovascular risk profile and an increased risk of early-onset (<45 years) ischemic stroke. Statins are effective hypolipidemic drugs that reduce cardiovascular-related morbidity and death in patients with or without established atherosclerotic vascular disease. We report a patient whose frequent attacks of typical aura with migraine completely resolved after the initiation of treatment with a statin. In this context, we comment on the possible effects of statins on the pathophysiology of migraine. We suggest that statins may be useful drugs in the treatment of migraine because they could reduce the increased cardiovascular risk in these patients and also attenuate migraine attacks. Only a randomized prospective study in this population could provide a definite answer to these speculations.

Dyslipidaemia, Hypercoagulability and the Metabolic Syndrome

The metabolic syndrome is a clustering of risk factors including central obesity, insulin resistance, dyslipidaemia and hypertension. This syndrome is associated with increased risk of cardiovascular disease and is a common early abnormality in the development of type 2 diabetes. The pathogenesis of the syndrome has multiple origins. Obesity and sedentary lifestyle coupled with genetic factors interact to produce the syndrome. Here, we consider two components of the metabolic syndrome, dyslipidaemia and hypercoagulability.

Preventing Type 2 Diabetes in High Risk Patients: An Overview of Lifestyle and Pharmacological Measures

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a common disease that is associated with an increased risk of vascular complications. The incidence of T2DM is also increasing. It follows that T2DM prevention is important.

METHODS

Relevant articles (review articles, randomised studies and large cohort and case-control studies) were identified through a Medline search (up to March 2005).

RESULTS

The first trials on T2DM prevention were based on lifestyle intervention. The results of these studies were impressive since they demonstrated that even a small reduction in weight could significantly reduce the incidence of T2DM. However, the main disadvantage of lifestyle measures is that they are difficult to achieve and sustain. Therefore, pharmacological interventions have also been evaluated. The results of trials using metformin, orlistat, nateglinide, acarbose, thiazolidinediones, hormone replacement therapy, statins or fibrates are either encouraging or require more extensive evaluation. In addition, studies using antihypertensive drugs (mainly angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists) showed that these drugs could also reduce the progression to T2DM in high risk individuals.

CONCLUSIONS

T2DM has major quality of life and cost implications. Therefore, more research is needed to establish safe and cost effective ways to prevent this modern epidemic.

Effect of orlistat, micronised fenofibrate and their combination on metabolic parameters in overweight and obese patients with the metabolic syndrome: the FenOrli study

BACKGROUND

Obesity is becoming increasingly common worldwide and is strongly associated with the metabolic syndrome (MetS). MetS is considered to be a cluster of risk factors that increase the risk of vascular events.

OBJECTIVE

In an open-label randomised study (the FenOrli study) we assessed the effect of orlistat and fenofibrate treatment, alone or in combination on reversing the diagnosis of the MetS (primary end-point) as well as on anthropometric and metabolic parameters (secondary end-points) in overweight and obese patients with MetS but no diabetes.

METHODS

Overweight and obese patients (N = 89, body mass index (BMI) > 28 kg/m2) with MetS [as defined by the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III criteria] participated in the study. Patients were prescribed a low-calorie low-fat diet and were randomly allocated to receive orlistat 120 mg three times a day (tid) (O group), micronised fenofibrate 200 mg/day (F group), or orlistat 120 mg tid plus micronised fenofibrate 200 mg/day (OF group). Body weight, BMI, waist circumference, blood pressure, serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglyceride, creatinine (SCr) and uric acid (SUA) levels, as well as homeostasis model assessment (HOMA) index and liver enzyme activities were measured at baseline and after 3 months of treatment.

RESULTS

Of the 89 patients enrolled, three (one in each group) dropped out during the study due to side effects. After the 3-month treatment period, 43.5% of patients in the O group, 47.6% in the F group and 50% in the OF group no longer met the MetS diagnostic criteria (primary end-point, p < 0.0001 vs. baseline in all treatment groups). No significant difference in the primary end-point was observed between the three treatment groups. Significant reductions in body weight, BMI, waist circumference, blood pressure, TC, LDL-C, non-HDL-C, triglyceride and SUA levels, as well as gamma-glutamyl transpeptidase activity and HOMA index were observed in all treatment groups. In the OF group a greater decrease in TC (-26%) and LDL-C (-30%) was observed compared with that in the O and F groups (p < 0.01) and a more pronounced reduction of triglycerides (-37%) compared with that in the O group (p < 0.05). SUA levels and alkaline phosphatase activity decreased more in the F and OF groups compared with the O group (p < 0.05). Moreover, SCr significantly increased and estimated creatinine clearance decreased in the F and OF groups but they were not significantly altered in the O group (p < 0.01 for the comparison between O and either F or OF groups). Glucose (in groups O and OF), as well as insulin levels and HOMA index (in all groups), were significantly reduced after treatment (p < 0.05 vs. baseline).

CONCLUSION

The combination of orlistat and micronised fenofibrate appears to be safe and may further improve metabolic parameters in overweight and obese patients with MetS compared with each monotherapy.

Diagnosis and management of the metabolic syndrome in obesity

The metabolic syndrome is a constellation of interrelated abnormalities that increase the risk for cardiovascular disease and progression to type 2 diabetes. The prevalence of this syndrome is increasing because of the 'obesity epidemic'. The National Cholesterol Education Program Adult Treatment Panel III defined practical criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. Also, the International Diabetes Federation recently proposed another definition. The metabolic syndrome is a secondary target for cardiovascular risk reduction. Clinicians should identify individuals with this condition, assess their cardiovascular risk and treat them by an aggressive and multifaceted approach. The most effective therapeutic intervention in patients with the metabolic syndrome should focus on modest weight reduction and regular physical activity. Adoption of a healthier diet and smoking cessation are necessary. Drug therapy may be needed to achieve recommended goals if therapeutic lifestyle changes are not sufficient. Low-density lipoprotein cholesterol is the primary target of therapy (new aggressive goals should be achieved). Statins are probably the drugs of choice. Fibrates and nicotinic acid are also useful options. Hypertension should be managed aggressively probably starting with an inhibitor of the renin-angiotensin system or a calcium channel blocker and adding a low dose of a thiazide diuretic if necessary. Aspirin should be administered if the cardiovascular risk is high. In the future acarbose, metformin, meglitinides and thiazolidinediones may be used in patients with the metabolic syndrome to delay the onset of type 2 diabetes and reduce cardiovascular risk. Such an intense and multifactorial approach is likely to reverse the bad prognosis associated with the metabolic syndrome.

Effect of Apolipoprotein E Polymorphism on Serum Uric Acid Levels in Healthy Subjects

BACKGROUND

We have previously shown that apolipoprotein E (apo E-) polymorphism may affect serum creatinine concentration and predicted glomerular filtration rate in healthy individuals. On the other hand, there are limited data regarding the possible influence of apo E- polymorphism on serum uric acid (SUA) levels.

METHODS

Two hundred ninety (148 male, 142 female) apparently healthy white individuals were studied. apo E- genotypes, serum lipid parameters including apolipoproteins, insulin resistance using the homeostasis model assessment (HOMA) as a marker, serum and urine creatinine levels, and serum and urine uric acid concentration were determined in all participants.

RESULTS

The apo E-2 allele was associated with lower serum levels of total cholesterol, higher levels of triglycerides and apo E-, and increased serum creatinine concentration compared with the apo E-3 and apo E-4 alleles in our population. Furthermore, the apo E-2 allele was associated with higher SUA levels (321.3+/-101.1 micrmol/L [5.4+/-1.7 mg/dL]) compared with the apo E-3 allele (261.8+/-89.2 micromol/L [4.4+/-1.5 mg/dL]; p= .012) and the apo E-4 allele (243.9+/-65.4 micromol/L [4.1+/-1.1 mg/dL]; p= .010), whereas the apo E-2 allele was associated with a nonsignificantdecrease in the fractional renal excretion of uric acid (FEUA) compared with the apo E-3 and apo E-4 alleles (7.9+/-2.2% vs 8.7+/-4.2% vs 8.9+/-5.1%, respectively; p = .53). These observations remained statistically significant when the effect of apo E- polymorphism on SUA levels was adjusted for gender, age, systolic and diastolic blood pressure, body mass index, serum creatinine, and triglyceride and apo E- levels, as well as for HOMA index and FEUA.

CONCLUSIONS

Our data provide evidence, for the first time, that the apo E-2 allele is independently associated with increased SUA levels in healthy individuals.

A review of the metabolic effects of sibutramine

BACKGROUND

Obesity is associated with an increased incidence of diabetes, hypertension, dyslipidaemia and coronary artery disease. Current management strategies of obesity include lifestyle management strategies of obesity include lifestyle interventions and pharmaco therapy. Sibutramine is a drug with established efficacy in weight reduction and maintenance of weight loss. It reduces food intake and attenuates the fall in reduces food intake and attenuates the fall in metabolic rate associated with weight loss.

OBJECTIVE

To review the metabolic effects associated with sibutramine use.

METHODS

Relevant articles were identified through a Medline search (up to December 2004).

RESULTS

Weight loss with sibutramine treatment is associated with improved insulin sensitivity and a fall in glycosylated haemoglobin levels in type 2 diabetic patients. In most trials sibutramine exerted favourable effects on lipids, especially exerted favourable effects on lipids, especially on high density lipoprotein (HDL) cholesterol and triglycerides, as well as on the total:HDL cholesterol ratio. Sibutramine also lowers serum uric acid concentrations. Furthermore, this drug seems to favourably influence adipocytokines; it reduces serum leptin and resistin levels and increases adiponectin levels. Sibutramine also exerts a beneficial effect on hyper androgenaemia in obese women with polycystic ovary syndrome. Preliminary findings also suggest that weight loss following treatment with sibutramine is useful in patients with non-alcoholic fatty liver disease (NAFLD).

CONCLUSION

Weight loss following sibutramine administration is associated with several favourable metabolic effects.

A review of the lipid-related effects of fluvastatin

BACKGROUND

Statin therapy has been shown to significantly decrease vascular events and overall mortality in primary and secondary prevention trials. This review considers the pharmacology, nonlipid-lowering effects and clinical trial evidence of fluvastatin based on a survey of PubMed entries.

FINDINGS

Recent clinical data show that treatment with fluvastatin is associated with a variety of benefits in different high-risk populations along with a good safety profile. Fluvastatin exerts non-lipid lowering-associated pleiotropic effects in both clinical and experimental studies. Furthermore, an extended-release formulation of fluvastatin with a favourable pharmacokinetic profile is available.

CONCLUSION

Treatment with fluvastatin offers a convenient, safe and evidence-based approach to managing dyslipidaemias and preventing vascular events.

Alterations of paraoxonase and platelet-activating factor acetylhydrolase activities in patients on peritoneal dialysis

OBJECTIVE

The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD.

DESIGN

A cross-sectional study.

SETTING

A university medical center.

PARTICIPANTS

56 PD patients of Caucasian origin and 86 matched controls were studied.

MEASUREMENTS

In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined.

RESULTS

The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found.

CONCLUSION

The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients.