Smoking cessation increases the resistance of low-density lipoprotein to oxidation

The effects of smoking cessation on the susceptibility to oxidation of low-density lipoprotein (LDL) was investigated in 14 men who quit smoking for 3 months. LDL was isolated and susceptibility of LDL to V-70 (4-methoxy-2,4-dimethylvalerinitrile)-mediated oxidation was assessed by measuring conjugated diene production at 234 nm, the lag phase being a measure of the resistance of LDL to oxidation. The mean duration of the lag phase became 1.9-fold longer after 3 months (P<0.001). The result suggests that the increase in resistance of LDL to oxidation contributes to the reduction of the risk of coronary heart disease by smoking cessation.     

High-density lipoprotein, but not low-density lipoprotein cholesterol levels influence short-term prognosis after acute coronary syndrome: results from the MIRACL trial.

AIMS: Patients with acute coronary syndrome (ACS) in the Myocardial Ischaemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study had diminished cardiovascular events after 16 weeks of treatment of atorvastatin 80 mg daily. We determined whether plasma lipoproteins at baseline and then at 6 weeks after randomization predicted clinical outcome. METHODS AND RESULTS: Cox proportional hazards models were constructed to determine relations between lipoproteins and clinical endpoint events. Baseline LDL cholesterol (LDL-C) did not predict outcome. In contrast, baseline HDL-C predicted outcome with a hazard ratio of 0.986 per mg/dL increment in HDL-C, P<0.001, indicating 1.4% reduction in risk for each 1 mg/dL increase in HDL-C. Atorvastatin treatment profoundly lowered LDL-C, but had minimal effect on HDL-C. Neither Week 6 LDL-C nor absolute change of LDL-C from baseline by Week 6 had any significant impact on clinical endpoints occurring between Week 6 and Week 16 after randomization. CONCLUSION: Plasma HDL-C, but not LDL-C, measured in the initial stage of ACS predicts the risk of recurrent cardiovascular events over the ensuing 16 weeks. LDL-C reduction does not account for the clinical risk reduction with atorvastatin treatment after ACS. This finding may suggest that the clinical benefit of atorvastatin after ACS is mediated by qualitative changes in the LDL particle and/or by non-lipid (pleiotropic) effects of the drug.     

Effect of ezetimibe on low-density lipoprotein subtype distribution: results of a placebo-controlled, double-blind trial in patients treated by regular low-density lipoprotein apheresis and statins

Ezetimibe, a cholesterol absorption inhibitor, can be combined with statins to lower low-density lipoprotein (LDL) cholesterol. We have previously shown that ezetimibe can decrease LDL cholesterol by 16% even in patients treated by regular LDL apheresis and statins (Atherosclerosis. 2005;180:107-112). However, it is unclear whether ezetimibe decreases all LDL subfractions equally in patients with hypercholesterolemia. We therefore evaluated the effect of ezetimibe (5 weeks, 10 mg/d) on LDL subtype distribution in a placebo-controlled, double-blind randomized crossover study in 20 patients (age, 56+/-9 years; body mass index, 27.5+/-4 kg/m2) with severe hyperlipoproteinemia and coronary heart disease who are treated by statins and regular LDL apheresis. Both treatment periods (placebo and ezetimibe) were separated by a 5-week washout period. Low-density lipoprotein subtype distribution was determined at the end of each treatment period before apheresis by density gradient ultracentrifugation (LDL1, 1.020-1.024; LDL2, 1.025-1.029; LDL3, 1.030-1.034; LDL4, 1.035-1.040; LDL5, 1.041-1.047; LDL6, 1.048-1.057; LDL7, 1.058-1.066 g/mL). Overall, the LDL subtype distribution did not change significantly (large-buoyant LDL [LDL1+LDL2], 17.2%+/-6.4% vs 16.3%+/-7.1%; intermediate LDL [LDL3+LDL4], 49.3%+/-4.5% vs 48.2%+/-5.2%; small-dense LDL [LDL5+LDL6+LDL7], 33.5%+/-8.0% vs 35.5%+/-10% during placebo and ezetimibe treatments, respectively). With respect to the individual LDL subfractions, cholesterol was significantly (P<.05, Wilcoxon test) reduced by ezetimibe in LDL1 to LDL5 with a somewhat more pronounced reduction in larger LDL (mean+/-SD, -20%+/-28%, -17%+/-32%, -14%+/-25%, -13%+/-27%, -11%+/-21%, -7%+/-21%, -4%+/-19%; median, -28%, -12%, -18%, -16%, -4%, -4%, -2% for LDL subfractions 1-7, respectively). We therefore conclude that ezetimibe decreases cholesterol in nearly all LDL subfractions. Although this was established in patients concomitantly treated with statins and apheresis, this may also hold true in other clinically relevant situations.     

The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals

BACKGROUND: It has been suggested that a low dietary intake of antioxidant vitamins and minerals increases the incidence rate of cardiovascular disease and cancer. To date, however, the published results of randomized, placebo-controlled trials of supplements containing antioxidant nutrients have not provided clear evidence of a beneficial effect. We tested the efficacy of nutritional doses of supplementation with a combination of antioxidant vitamins and minerals in reducing the incidence of cancer and ischemic cardiovascular disease in the general population. METHODS: The Supplementation en Vitamines et Mineraux Antioxydants (SU.VI.MAX) study is a randomized, double-blind, placebo-controlled primary prevention trial. A total of 13 017 French adults (7876 women aged 35-60 years and 5141 men aged 45-60 years) were included. All participants took a single daily capsule of a combination of 120 mg of ascorbic acid, 30 mg of vitamin E, 6 mg of beta carotene, 100 mug of selenium, and 20 mg of zinc, or a placebo. Median follow-up time was 7.5 years. RESULTS: No major differences were detected between the groups in total cancer incidence (267 [4.1%] for the study group vs 295 [4.5%] for the placebo group), ischemic cardiovascular disease incidence (134 [2.1%] vs 137[2.1%]), or all-cause mortality (76 [1.2%] vs 98 [1.5%]). However, a significant interaction between sex and group effects on cancer incidence was found (P = .004). Sex-stratified analysis showed a protective effect of antioxidants in men (relative risk, 0.69 [95% confidence interval [CI], 0.53-0.91]) but not in women (relative risk, 1.04 [95% CI, 0.85-1.29]). A similar trend was observed for all-cause mortality (relative risk, 0.63 [95% CI, 0.42-0.93] in men vs 1.03 [95% CI, 0.64-1.63] in women; P = .11 for interaction). CONCLUSIONS: After 7.5 years, low-dose antioxidant supplementation lowered total cancer incidence and all-cause mortality in men but not in women. Supplementation may be effective in men only because of their lower baseline status of certain antioxidants, especially of beta carotene.     

Treatment of hypothyroidism reduces low-density lipoproteins but not lipoprotein(a).

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL) particle in which apolipoprotein B-100 (apo B) is attached to a large plasminogen-like protein called apolipoprotein(a) [apo(a)]. Apo(a) has several genetically determined phenotypes differing in molecular weight, to which Lp(a) concentrations in plasma are inversely correlated. LDL and apo B levels are often elevated in untreated hypothyroidism and lowered by thyroxine (T4) treatment, probably due to an increase in LDL receptors. We measured plasma concentrations of LDL, apo B, and Lp(a) in 13 patients with symptomatic primary hypothyroidism before and during T4 therapy. The mean concentration of LDL decreased significantly (P = .006) from 6.05 mmol/L to 4.07 mmol/L, and the mean concentration of apo B decreased significantly (P = .005) from 1.42 g/L to 1.12 g/L. Median Lp(a) concentrations remained unchanged (P = .77); they were 17.05 mg/dL before and 16.59 mg/dL during T4 treatment. In both the untreated condition and during substitution therapy, Lp(a) levels were higher in patients than in healthy controls, probably due to a relatively high frequency of the small Lp(a) phenotypes in our patients. Since Lp(a) contains apo B, which is a ligand for the LDL receptor, it is surprising that Lp(a) is not reduced along with LDL and apo B. These findings suggest that the catabolism of LDL and Lp(a) differ in some respect, and that thyroid hormones have little, if any, effect on Lp(a).     

Effect of low-density lipoprotein cholesterol on angiotensin II sensitivity: a randomized trial with fluvastatin

Increased angiotensin II (Ang II) sensitivity predisposes to hypertension and plaque instability. Raised low-density lipoprotein cholesterol (LDL-c) may increase Ang II sensitivity, but evidence in humans for this effect of LDL-c is limited. In 28, healthy, nonsmoking subjects, aged 30+/-8 years, with familial hypercholesterolemia, we determined the difference in infusion rate of Ang II and norepinephrine required to increase systolic blood pressure by 20 mm Hg (Pd-20) after 4 weeks of placebo and fluvastatin 80 mg daily in a randomized, double-blind, placebo-controlled, crossover study. Before infusions were started, fasting blood samples were taken to measure lipids. After 4 weeks of placebo, the mean LDL-c concentration was 6.3+/-1.4 mmol/L. The average decrease of LDL-c was 1.7+/-0.7 mmol/L after 4 weeks of fluvastatin (P<0.001). The mean Pd-20 for Ang II increased by 1.28 ng/kg per minute (95% CI, 2.05 to 0.50; P=0.002) on fluvastatin, corresponding with a 26% decrease in Ang II sensitivity. Ang II sensitivity, however, remained increased compared with normocholesterolemic controls. The Pd-20 values for norepinephrine were unaffected by fluvastatin. The present study in healthy, young subjects with isolated hypercholesterolemia shows an increased sensitivity to Ang II that partly can be restored by LDL-c-lowering therapy. These findings indicate that LDL-c levels directly influence Ang II sensitivity.     

Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial

BACKGROUND: Despite the richness in antioxidants of the Mediterranean diet, to our knowledge, no randomized controlled trials have assessed its effect on in vivo lipoprotein oxidation. METHODS: A total of 372 subjects at high cardiovascular risk (210 women and 162 men; age range, 55-80 years), who were recruited into a large, multicenter, randomized, controlled, parallel-group clinical trial (the Prevención con Dieta Mediterránea [PREDIMED] Study) directed at testing the efficacy of the traditional Mediterranean diet (TMD) on the primary prevention of coronary heart disease, were assigned to a low-fat diet (n = 121) or one of 2 TMDs (TMD + virgin olive oil or TMD + nuts). The TMD participants received nutritional education and either free virgin olive oil for all the family (1 L/wk) or free nuts (30 g/d). Diets were ad libitum. Changes in oxidative stress markers were evaluated at 3 months. RESULTS: After the 3-month interventions, mean (95% confidence intervals) oxidized low-density lipoprotein (LDL) levels decreased in the TMD + virgin olive oil (-10.6 U/L [-14.2 to -6.1]) and TMD + nuts (-7.3 U/L [-11.2 to -3.3]) groups, without changes in the low-fat diet group (-2.9 U/L [-7.3 to 1.5]). Change in oxidized LDL levels in the TMD + virgin olive oil group reached significance vs that of the low-fat group (P = .02). Malondialdehyde changes in mononuclear cells paralleled those of oxidized LDL. No changes in serum glutathione peroxidase activity were observed. CONCLUSIONS: Individuals at high cardiovascular risk who improved their diet toward a TMD pattern showed significant reductions in cellular lipid levels and LDL oxidation. Results provide further evidence to recommend the TMD as a useful tool against risk factors for CHD. Trial Registration isrctn.org Identifier: ISRCTN35739639.     

Baseline characteristics of participants in the JUPITER trial, a randomized placebo-controlled primary prevention trial of statin therapy among individuals with low low-density lipoprotein cholesterol and elevated high-sensitivity C-reactive protein

The Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) is a randomized, double-blind, placebo-controlled primary prevention trial of statin therapy among persons with average to low levels of low-density lipoprotein (LDL) cholesterol who are at increased cardiovascular risk due to elevated plasma concentrations of the inflammatory biomarker high-sensitivity C-reactive protein (hs-CRP). A total of 17,802 persons with LDL cholesterol<130 mg/dl (3.36 mmol/L) and hs-CRP>or=2 mg/L were recruited from 26 countries and randomly allocated to 20 mg/day rosuvastatin or placebo. In contrast to previous studies of statin therapy in primary prevention, JUPITER is evaluating a group with modest plasma concentrations of LDL cholesterol (median 108 mg/dl, interquartile range 94 to 119). Further, the trial includes 6,801 women (38.2%) and 5,577 participants with metabolic syndrome (32.1%). Thus, in addition to broadening our understanding of statin therapy and inflammation, the JUPITER trial will provide important and clinically relevant information on primary prevention among patients who do not currently qualify for lipid-lowering therapy. In conclusion, as 20 mg of rosuvastatin can reduce LDL cholesterol by up to 50%, JUPITER will also provide crucial safety data for several thousand patients who should achieve LDL cholesterol levels<50 mg/dl on a long-term basis.     

Hormone replacement therapy and acquired resistance to activated protein C: results of a randomized, double-blind, placebo-controlled trial

Recent studies suggest that low-dose oral contraceptives may cause acquired resistance to activated protein C (APC). The aims of this study were to determine whether hormone replacement therapy (HRT) may also induce acquired APC resistance and to study the effects of APC resistance on the risk of recurrent thrombosis. The patients comprised 140 females with at least one previous venous thromboembolism (VTE), who were randomized to receive continuous treatment with 2 mg 17-beta-oestradiol and 1 mg norethisterone acetate (n = 71) or placebo (n = 69). Normalized APC sensitivity ratios (nAPCsr) were calculated by measurement of the effect of APC on thrombin generation in plasma collected at baseline and after 3 months of treatment. Of the 140 women, 121 had plasma samples collected both at baseline and after 3 months. The nAPCsr increased significantly (P < 0.001) on HRT (n = 62), both in females not carrying the factor V(Leiden) mutation [mean change 0.57 (95% CI 0.45-0.70), n = 50] and in females heterozygous for the factor V(Leiden) mutation [mean change 1.10 (0.71-1.49), n = 12], but remained unchanged on placebo (n = 59). The baseline nAPCsr as well as the increase in nAPCsr associated with HRT use was not higher in the five women who subsequently developed recurrent VTE. Free protein S and free TFPI were both important parameters for the acquired APC resistant phenotype. We conclude that HRT diminishes the efficacy by which APC downregulates in-vitro thrombin formation in a similar fashion to that observed with low-dose oral contraceptives, but the increase in nAPCsr alone is not sufficient to explain the increased risk of VTE associated with use of HRT.     

Etanercept for active Crohn's disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND & AIMS: We evaluated etanercept, a human soluble tumor necrosis factor receptor: Fc fusion protein, for the treatment of active Crohn's disease. METHODS: Forty-three patients with moderate to severe Crohn's disease were enrolled in an 8-week placebo-controlled trial. Patients were randomized to subcutaneous etanercept 25 mg or placebo twice weekly. The primary outcome measure was clinical response at week 4, defined as a decrease in the baseline Crohn's Disease Activity Index score > or =70 points or a Crohn's Disease Activity Index score <150 points. RESULTS: At week 4, 39% of etanercept-treated patients had clinical response as compared with 45% of placebo-treated patients (P = 0.763). The frequency of common adverse events including headache, new injection site reaction, asthenia, abdominal pain, Crohn's disease-related anemia, and skin disorders was similar in both groups. Likewise, the frequency of severe or serious adverse events was similar in both groups. CONCLUSIONS: Subcutaneous etanercept at a dose of 25 mg twice weekly is safe, but not effective, for the treatment of patients with moderate to severe Crohn's disease. The dose of etanercept administered in this study is that approved for rheumatoid arthritis. Higher doses or more frequent dosing may be required to attain a response in patients with active Crohn's disease.     

Onercept for moderate-to-severe Crohn's disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND AND AIMS: Onercept is a recombinant, soluble human p55 receptor to tumor necrosis factor-alpha. METHODS: A randomized, double-blind, placebo-controlled, dose-ranging trial was performed to evaluate the efficacy of onercept induction therapy in patients with Crohn's disease (CD). Patients (n = 207) with moderate-to-severe acute or chronic active CD were randomized to receive subcutaneous onercept (10, 25, 35, or 50 mg) or placebo 3 times weekly for 8 weeks. Primary analysis was induction of remission (defined as a CD activity index score < or = 150) at week 8. RESULTS: A total of 104 patients had acute active CD. Remission rates at week 8 were 23.5% for placebo (n = 17), and 34.8%, 20.0%, 26.1%, and 28.6% for onercept 10 mg (n = 23), 25 mg (n = 20), 35 mg (n = 23), and 50 mg (n = 21), respectively (P = .98). A total of 103 patients had chronic active CD. Remission rates at week 8 were 23.8% for placebo (n = 21), and 23.8%, 9.1%, 35.3%, and 13.6% for onercept 10 mg (n = 21), 25 mg (n = 22), 35 mg (n = 17), and 50 mg (n = 22), respectively (P = .66). There were no differences between treatment groups in the incidence of adverse events. However, mild-to-moderate injection-site reactions occurred in up to 12% of onercept-treated patients. CONCLUSIONS: Onercept was well tolerated but was not effective at the doses studied in patients with active CD.     

Topical tetracaine prior to arterial puncture: a randomized, placebo-controlled clinical trial

The objective of this randomized, double-blind, placebo-controlled clinical trial was to determine whether a topical anesthetic agent (tetracaine) provides effective local analgesia prior to radial arterial puncture. Tetracaine or placebo gel was applied 45 min prior to arterial puncture to patients who were referred for elective arterial blood gas. The primary outcome was the patient's perception of pain associated with the procedure as measured by a visual analog scale. Fifty patients were randomized into the study, 24 received tetracaine and 26 placebo. Mean pain score on the visual analog scale was 26.2 +/- 32.6 for the tetracaine-treated patients and 23.8 +/- 27.4 for the placebo-treated patients (P = 0.78). Mean time from the first skin puncture to successful procurement of 1 ml of arterial blood was 70 +/- 103s in the tetracaine group and 49 +/- 48s in the placebo group (P = 0.40). Difficulty of arterial puncture as assessed by the respiratory therapist performing the test was identical for the two groups (P = 0.86). We conclude that tetracaine gel did not decrease patient's perception of pain associated with arterial puncture, nor did its use facilitate the ABG procedure.     

Methotrexate in Crohn's disease: results of a randomized, double-blind, placebo-controlled trial.

BACKGROUND/AIMS: Immunosuppression with methotrexate may be useful in the treatment of Crohn's disease. We tested the efficacy of methotrexate in refractory Crohn's disease in a randomized, controlled trial. METHODOLOGY: Randomized, double-blind placebo-controlled trial of methotrexate in 33 patients with steroid-dependent Crohn's disease, 33% of whom had previously failed therapy with 6-mercaptopurine. Patients were given placebo or oral methotrexate 15 mg/week, or adjusted up to 22.5 mg/week, for up to 1 year or until treatment failure. Outcome was assessed by reduction in prednisone dosage, Crohn's Disease Activity Index, hospital admission, and laboratory parameters. RESULTS: Four patients were dropped from the study for non-compliance and one because of intercurrent illness, and 28 patients could be evaluated. Fewer methotrexate-treated patients (6/13 or 46%) had flares of Crohn's disease as compared to placebo-treated patients (12/15 or 80%), but this did not achieve statistical significance (p<0.1). There was a non-significant trend toward an increased number of significant side effects in the methotrexate-treated patients (3/13 or 23%) as compared to the placebo-treated patients (0/15 or 0%) (p<0.2). Laboratory indices of inflammation did not differ between the two groups. CONCLUSIONS: The methotrexate-treated group showed a trend toward fewer Crohn's disease flares, balanced by an increased number of significant side effects.     

Treatment of rheumatoid arthritis with L-histidine: a randomized, placebo-controlled, double-blind trial.

A randomized cooperative double-blind trial of oral L-histidine for the treatment of rheumatoid arthritis was carried out. Patients were treated with either L-histidine 4.5 g daily, or placebo, for 30 weeks. None of the clinical measurements showed an advantage of histidine over placebo. A small decrease in rheumatoid factor titer and a small increase in hematocrit were found only in the histidine group. There was suggestive evidence of a beneficial effect of histidine in patients with more active and prolonged disease, based upon subjective doubld-blind evaluations by physicians and patients. No adverse effects of histidine therapy were noted. Histidine cannot be advocated as a therapeutic agent in rheumatoid arthritis, but further studies in certain groups of patients seem justified.     

Thrombolysis in patients with unstable angina improves the angiographic but not the clinical outcome. Results of UNASEM, a multicenter, randomized, placebo-controlled, clinical trial with anistreplase.

BACKGROUND. The value of thrombolytic therapy in unstable angina is unclear. METHODS AND RESULTS. To study this problem, 159 patients were studied in a double-blind, placebo-controlled multicenter trial. Patients without a previous myocardial infarction, with a typical history of unstable angina, and ECG abnormalities indicative of ischemia were included. After baseline angiography, study medication (anistreplase or placebo) was given. Angiography was repeated after 12-28 hours. A significant decrease occurred in diameter stenosis between the first and second angiogram in the anistreplase group compared with the placebo group (11% versus 3%, p = 0.008). This difference was caused by reopening of occluded vessels in the thrombolytic group. However, no beneficial clinical effects of thrombolytic treatment were found. Bleeding complications were significantly higher in patients who received thrombolytic therapy (21 versus seven patients, p = 0.001). CONCLUSIONS. Thus, angiographic but no clinical improvement after thrombolytic treatment with anistreplase was found in patients with unstable angina with an excess of bleeding complications. Therefore, thrombolytic treatment cannot be recommended in patients diagnosed as having unstable angina until proven otherwise.