Identification of allele-specific KIV-2 repeats and impact on Lp(a) measurements for cardiovascular disease risk

The abundance of Lp(a) protein holds significant implications for the risk of cardiovascular disease (CVD), which is directly impacted by the copy number (CN) of KIV-2, a 5.5 kbp sub-region. KIV-2 is highly polymorphic in the population and accurate analysis is challenging. In this study, we present the DRAGEN KIV-2 CN caller, which utilizes short reads. Data across 166 WGS show that the caller has high accuracy, compared to optical mapping and can further phase ~50% of the samples. We compared KIV-2 CN numbers to 24 previously postulated KIV-2 relevant SNVs, revealing that many are ineffective predictors of KIV-2 copy number. Population studies, including USA-based cohorts, showed distinct KIV-2 CN, distributions for European-, African-, and Hispanic-American populations and further underscored the limitations of SNV predictors. We demonstrate that the CN estimates correlate significantly with the available Lp(a) protein levels and that phasing is highly important.

Cardiovascular benefits outweigh risks in patients with atrial fibrillation in REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial)

Background/Introduction

REDUCE-IT, a multinational, double-blind trial, randomized 8179 statin-treated patients with controlled low density lipoprotein cholesterol, elevated triglycerides, and cardiovascular (CV) risk, to icosapent ethyl (IPE) 4 grams/day or placebo. IPE reduced the primary (CV death, myocardial infarction [MI], stroke, coronary revascularization, hospitalization for unstable angina) and key secondary (CV death, MI, stroke) endpoints 25% and 26%, respectively (each p<0.0001), and individual components including stroke (28%), MI (31%), cardiac arrest (48%), and sudden cardiac death (31%) (all p≤0.01). With IPE, bleeding was greater (11.8% vs 9.9%; p=0.006), serious bleeding trended higher (2.7% vs 2.1%; p=0.06), and atrial fibrillation/flutter (AF/F) hospitalization endpoints increased (3.1% vs 2.1%; p=0.004).

Purpose

To evaluate the effects of IPE on the risk of CV events and safety measures in patients by either history of AF/F or in-study occurrence of positively adjudicated AF/F hospitalization.

Methods

Conduct post hoc efficacy and safety subgroup analyses of patients with or without either baseline history of AF/F or in-study adjudicated AF/F hospitalization, including hospitalization for ≥24 hours; AF/F not meeting endpoint criteria were reported as adverse events.

Results

Patients with (n=751; 9.2%) AF/F history at baseline (vs without; n=7428; 90.8%) (Figure 1), or those with (n=211; 2.6%) positively adjudicated in-study AF/F hospitalization endpoints (vs without; n=7968; 97.4%) (Figure 2), had higher event rates of primary, key secondary, and fatal or nonfatal stroke endpoints, but relative risk reductions with IPE were not significantly different (all interaction p-values [pint]=ns). Similar reductions were observed with IPE across the prespecified endpoint testing hierarchy in patients with or without AF/F history or in-study hospitalization endpoints. Patients with baseline AF/F history had similar relative risk for in-study occurrence of AF/F hospitalization with IPE versus placebo (pint=0.21) but had greater absolute risk (12.5% vs 6.3%, IPE vs placebo) vs patients without baseline AF/F history (2.2% vs 1.6%, IPE vs placebo); i.e., recurrent AF/F in those with a prior history of AF/F was more prevalent than de novo AF/F. Serious bleeding trended higher regardless of AF/F history or in-study AF/F hospitalization endpoints (all pint=ns); absolute risk of serious bleeding was greater in patients with AF/F history at baseline (7.3% vs 6.0%) vs those without a baseline history of AF/F (2.3% vs 1.7%), and serious bleeding also trended higher in patients with in-study AF/F hospitalization (8.7% vs 6.0%) vs without (2.5% vs 2.0%) [all IPE vs placebo].

Conclusion

REDUCE-IT patients with AF/F history or in-study AF/F hospitalization endpoints had greater CV risk, but similar relative risk reduction in primary, key secondary, and fatal or nonfatal stroke endpoints with IPE.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amarin Pharma, Inc.

P6193Dalcetrapib reduces incident diabetes in patients with recent acute coronary syndrome

Background

Among patients with acute coronary syndrome (ACS) who do not have diabetes, incident diabetes is common and associated with an adverse prognosis. Some data suggest that high density lipoprotein (HDL) has favourable effects on beta cell function and that cholesteryl ester transfer protein (CETP) inhibitors reduce incident type 2 diabetes in conjunction with increased HDL cholesterol (HDL-C) concentration. Dalcetrapib is a CETP inhibitor under ongoing evaluation as a potential cardiovascular therapy.

Purpose

We compared the effect of treatment with dalcetrapib or placebo on incident diabetes in patients with recent acute coronary syndrome (ACS).

Methods

In the dal-OUTCOMES trial, 15,871 patients were randomly assigned to treatment with dalcetrapib 600 mg or placebo daily, beginning 4–12 weeks after ACS. Absence of diabetes at baseline was based upon medical history, no use of diabetes medication, haemoglobin A1c <6.5%, and plasma glucose level <7 mmol/L (if measured under fasting conditions) or <11.1 mmol/L (if measured under non-fasting conditions). Among these patients, incident diabetes after randomization was defined by any diabetes-related adverse event, use of a diabetes medication, HbA1c ≥6.5%, or two measurements of plasma glucose ≥7 mmol/L (fasting) or ≥11.1 mmol/L (non-fasting). The association of incident diabetes with baseline and on-treatment HDL-C was determined.

Results

At baseline, 10621 patients (67% of the trial cohort) did not have diabetes and formed the analysis cohort. Over median follow-up of 31 months, incident diabetes was identified in 392 of 5314 patients (7.4%) assigned to dalcetrapib and 505 of 5307 (9.5%) assigned to placebo (odds ratio [OR] 0.76; 95% confidence interval [CI] 0.66–0.87; P<0.001). This corresponds to an absolute reduction in incident diabetes of 2.1%, and a need to treat 47 patients (for 31 months) to prevent 1 case of diabetes. Kaplan-Meier estimates of the cumulative incidence of diabetes are shown in the Figure. Across both treatment groups, incident diabetes was inversely associated with baseline HDL-C (OR 0.98 for 1 mg/dL increase in baseline HDL-C; 95% CI 0.97–0.98, P<0.001). In the dalcetrapib group, there was a further inverse association of incident diabetes with the change in HDL-C on assigned treatment (OR 0.98 for 1 mg/dL increase in HDL-C from baseline; 95% CI 0.97–0.99, P=0.002). Dalcetrapib was safe and generally well-tolerated in the trial.

Conclusions

In patients with recent ACS who do not have diabetes at baseline, incident diabetes is common. Dalcetrapib treatment reduced the relative risk of incident diabetes by 24% and the absolute risk by 2.1% over a median of 31 months. The reduction in incident diabetes with dalcetrapib was associated with increased HDL-C on treatment.

Acknowledgement/Funding

The dal-OUTCOMES trial was funded by F. Hoffmann LaRoche

P5364Safety profile of bempedoic acid: pooled analysis of 4 phase 3 clinical trials

Background/Introduction

Bempedoic acid (BA), an oral, first-in-class, ATP-citrate lyase inhibitor, lowers low-density lipoprotein cholesterol (LDL-C) in patients who do not achieve sufficient lipid lowering with guideline-recommended first-line therapies.

Purpose

We evaluated the safety profile of BA in phase 3 trials.

Methods

Data were pooled from 4 randomised, double-blind, placebo-controlled studies that enrolled patients with hyperlipidaemia who were receiving stable lipid-lowering therapy (LLT; maximally tolerated statins +/− nonstatin therapies) and required additional LDL-C lowering. Patients were randomised (2:1) to BA 180 mg or placebo daily for 12 to 52 weeks.

Results

Median exposure for 3621 patients (2424 BA, 1197 placebo) was 363 days. Background LLT included a statin +/− other LLT (83.8%), nonstatin LLT alone (9.4%), or none (6.8%). Adverse event (AE) and serious AE rates were similar between groups (Table). The most common AEs in the BA and placebo groups were nasopharyngitis (7.4% vs 8.9%), myalgia (4.9% vs 5.3%), and urinary tract infection (4.5% vs 5.5%). Rates of new-onset/worsening diabetes were 4.0% for BA and 5.6% for placebo. No AEs leading to discontinuation differed by ≥0.5% between treatments. All fatal AEs were judged by the investigator as unrelated to treatment. A trend was observed for a lower 3-component major adverse cardiac event rate with BA vs placebo (hazard ratio, 0.85; 95% confidence interval: 0.53 to 1.37). Changes in uric acid, creatinine, and haemoglobin were apparent at week 4, stable over time, and reversible after stopping BA. Gout occurred in 1.4% and 0.4% of patients in the BA and placebo groups, respectively. The safety profile of BA was consistent across background therapies, demographics, and disease characteristics.

Table 1. Safety summary Placebo (n=1197) BA (n=2424) Any AE / SAE, % (n) 72.5 (868) / 13.3 (159) 73.1 (1171) / 14.1 (341) Drug discontinuation due to an AE, % (n) 7.8 (93) 11.3 (273) AE with a fatal outcome, % (n) 0.3 (4) 0.8 (19) Aminotransferase elevation >3 x ULN, % (n) 0.3 (3) 0.7 (18) Aminotransferase elevation >5 x ULN, % (n) 0.2 (2) 0.2 (6) Creatine kinase elevation >5 x ULN, % (n) 0.2 (2) 0.3 (8) Creatinine, mean change at week 12, mg/dL −0.002±0.11 0.046±0.12 Uric acid, mean change at week 12, mg/dL −0.02±0.82 0.82±0.97 Haemoglobin, mean change at week 12, g/dL 0.06±0.69 −0.31±0.71

Conclusion(s)

BA added to LLT was well tolerated, with a safety profile comparable to placebo.

Newer risk markers and surrogate endpoints in atherosclerosis management

Risk markers that allow improved and individualized assessment of atherosclerotic disease risk and response to treatment are needed. Current candidate markers include cell adhesion molecules, such as intercellular adhesion molecule-1 and E-selectin, and inflammatory markers, such as C-reactive protein; advances in genomics and proteomics will suggest additional candidate markers. Noninvasive imaging procedures such as electron-beam computed tomography and magnetic resonance imaging also show considerable promise for monitoring disease status and response to treatment, and ultimately could provide surrogate endpoints for clinical trials of therapeutic interventions.

Treating mixed dyslipidemias: why and how

Patients with only mildly elevated low-density lipoprotein cholesterol values but low high-density lipoprotein cholesterol (HDL-C) and/or high triglyceride levels are at high risk for cardiovascular disease. 3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (also known as statins) have been shown to slow coronary heart disease (CHD) progression, reduce CHD events in patients with low HDL-C levels, and raise HDL-C concentrations in patients with mixed dyslipidemias. Some, but not all trials of fibrates have shown benefit in patients with low HDL-C levels. Combination therapy with a statin plus either a fibrate or niacin is effective in improving the entire lipid profile, but may increase cost and side effects.

Glutamic acid decarboxylase antibodies are indicators of the course, but not of the onset, of diabetes in middle-aged adults: the Atherosclerosis Risk in Communities Study

To efficiently examine the association of glutamic acid decarboxylase antibody (GADA) positivity with the onset and progression of diabetes in middle-aged adults, we performed a case-cohort study representing the ~9-year experience of 10,275 Atherosclerosis Risk in Communities Study participants, initially aged 45-64 years. Antibodies to glutamic acid decarboxylase (GAD65) were measured by radioimmunoassay in 580 incident diabetes cases and 544 non-cases. The overall weighted prevalence of GADA positivity (>or=1 U/mL) was 7.3%. Baseline risk factors, with the exception of smoking and interleukin-6 (P <or= 0.02), were generally similar between GADA-positive and -negative individuals. GADA positivity did not predict incident diabetes in multiply adjusted (HR = 1.04; 95%CI = 0.55, 1.96) proportional hazard analyses. However, a small non-significant adjusted risk (HR = 1.29; 95%CI = 0.58, 2.88) was seen for those in the highest tertile (>or=2.38 U/mL) of positivity. GADA-positive and GADA-negative non-diabetic individuals had similar risk profiles for diabetes, with central obesity and elevated inflammation markers, aside from glucose, being the main predictors. Among diabetes cases at study's end, progression to insulin treatment increased monotonically as a function of baseline GADA level. Overall, being GADA positive increased risk of progression to insulin use almost 10 times (HR = 9.9; 95%CI = 3.4, 28.5). In conclusion, in initially non-diabetic middle-aged adults, GADA positivity did not increase diabetes risk, and the overall baseline profile of risk factors was similar for positive and negative individuals. Among middle-aged adults, with the possible exception of those with the highest GADA levels, autoimmune pathophysiology reflected by GADA may become clinically relevant only after diabetes onset.

Genetic variation and decreased risk for obesity in the Atherosclerosis Risk in Communities Study

AIM

To investigate the effects of variation in the leptin [LEP (19A>G)] and melanocortin-4 receptor [MC4R (V103I)] genes on obesity-related traits in 13 405 African-American (AA) and white participants from the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

We tested the association between the single-locus and multilocus genotypes and obesity-related measures [body mass index (BMI), body weight (BW), waist-hip ratio, waist circumference and leptin levels], adjusted for age, physical activity level, smoking status, diabetic status, prevalence of coronary heart disease, hypertension, stroke or transient ischaemic attack.

RESULTS

AA and white female carriers of the MC4R I103 allele exhibited significantly lower BW than non-carriers of this allele (p < 0.05 and p < 0.01 respectively). AA female carriers of both the LEP A19 allele and the MC4R I103 allele were 63% [odds ratio (OR) = 0.37, 95% confidence interval (CI) (0.18-0.78)] less likely to be obese, and white female carriers of the same two alleles were 46% [OR = 0.54, 95% CI (0.32-0.91)] less likely to be obese, than non-carriers of the variant alleles. Female carriers of both the LEP A19 and MC4R I103 alleles had significantly lower BW (p < 0.05), BMI (p < 0.05) and plasma leptin (p < 0.01) than the non-carriers of both the alleles. Carriers of the two variant alleles had lower BMI over the 9-year course of the ARIC study and significantly lower weight gain from age 25 years. No significant joint effect of these two variants was observed in males.

CONCLUSION

These results suggest that variation within the LEP and MC4R genes is associated with reduced risk for obesity in females.

Circulating oxidised low-density lipoprotein and intercellular adhesion molecule-1 and risk of type 2 diabetes mellitus: the Atherosclerosis Risk in Communities Study

AIMS/HYPOTHESIS

To evaluate the role of oxidative stress and inflammation in the aetiology of type 2 diabetes, we examined the association of oxidised LDL (ox-LDL) and soluble intercellular adhesion molecule-1 (sICAM-1) levels with type 2 diabetes incidence over 9 years in the Atherosclerosis Risk in Communities Study.

MATERIALS AND METHODS

In a large, prospective, case-cohort design, ox-LDL and sICAM-1 were measured in stored plasma samples collected at baseline in stratified samples of 581 diabetes cases and 572 non-cases selected from 10,275 middle-aged men and women without prevalent diabetes at baseline.

RESULTS

Compared with non-cases, diabetes cases had significantly higher mean baseline levels of ox-LDL and sICAM-1. Elevated ox-LDL and sICAM-1 were both associated with increased risk of incident diabetes after adjustment for age, sex, race and centre, with hazard ratios for the highest vs lowest tertiles of 1.68 (95% CI 1.25-2.24) and 1.91 (95% CI 1.45-2.50), respectively. After additional adjustment for fasting glucose, waist circumference, HDL-cholesterol, triacylglycerol, hypertension and C-reactive protein, only sICAM-1 remained an independent predictor of incident diabetes (hazard ratio 1.50; 95% CI 1.02-2.23).

CONCLUSIONS/INTERPRETATION

In this community-based cohort of middle-aged US adults, elevated plasma ox-LDL and sICAM-1 levels were associated with increased risk of type 2 diabetes. Measurement of ICAM-1 or ox-LDL, or other measures related to inflammation or oxidative stress, may be helpful in identifying those patient populations in which to test whether novel therapies that inhibit specific pathways related to inflammation or oxidative stress are beneficial in the prevention of diabetes in humans.

Leptin and incident type 2 diabetes: risk or protection?

AIMS/HYPOTHESIS

The aim of this study was to investigate the association of leptin levels with incident diabetes in middle-aged adults, taking into account factors purportedly related to leptin resistance.

SUBJECTS AND METHODS

We conducted a case-cohort study (570 incident diabetes cases and 530 non-cases) representing the 9-year experience of 10,275 participants of the Atherosclerosis Risk in Communities Study. Plasma leptin was measured by direct sandwich ELISA.

RESULTS

In proportional hazards models adjusting for age, study centre, ethnicity and sex, high leptin levels (defined by sex-specific cut-off points) predicted an increased risk of diabetes, with a hazard ratio (HR) comparing the upper with the lower quartile of 3.9 (95% CI 2.6-5.6). However, after further adjusting additionally for obesity indices, fasting insulin, inflammation score, hypertension, triglycerides and adiponectin, high leptin predicted a lower diabetes risk (HR=0.40, 95% CI 0.23-0.67). Additional inclusion of fasting glucose attenuated this protective association (HR=0.59, 95% CI 0.32-1.08, p<0.03 for linear trend across quartiles). In similar models, protective associations were generally seen across subgroups of sex, race, nutritional status and smoking, though not among those with lower inflammation scores or impaired fasting glucose (interaction p=0.03 for both).

CONCLUSIONS/INTERPRETATION

High leptin levels, probably reflecting leptin resistance, predict an increased risk of diabetes. Adjusting for factors purportedly related to leptin resistance unveils a protective association, independent of adiponectin and consistent with some of leptin's described protective effects against diabetes.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Characteristics of US adults with the metabolic syndrome and therapeutic implications

BACKGROUND

The third Adult Treatment Panel (ATP III) of the National Cholesterol Education Program defines clinical criteria for diagnosis of the metabolic syndrome, which increases cardiovascular risk and is a target for therapy.

AIM

We analysed the third National Health and Nutrition Examination Survey (NHANES III; 1988-94) to determine how many US adults meet these criteria and are recommended for lipid-modifying drug therapy by ATP III.

METHODS

NHANES III data were used to estimate the number of individuals with the metabolic syndrome and the number recommended for treatment by ATP III, based on 1990 census data.

RESULTS

An estimated 36.3 million (23%) US adults have the metabolic syndrome. Of these, 84% met the criterion for obesity, 76% for blood pressure, 75% for HDL-C, 74% for triglycerides and 41% for glucose. Most (54%) are in the higher risk categories of ATP III, yet only 39% overall are recommended for drug therapy by ATP III cutpoints; of these, most will achieve LDL-C targets with reductions of 35-40%. Of the 15.3 million individuals with the metabolic syndrome and triglycerides > or = 2.26 mmol/l (200 mg/dl), non-HDL-C is above ATP III recommendations in 11.6 million.

CONCLUSIONS

Of the large number of Americans with the metabolic syndrome, ATP III recommends drug therapy for only a minority, because LDL-C typically is not substantially elevated. Instead, high triglycerides and low HDL-C are more common; clinical trial data are needed to determine whether optimal therapy should focus on reductions in LDL-C or on comprehensive improvements to the lipid profile.

Efficacy and safety of ezetimibe coadministered with statins: randomised, placebo-controlled, blinded experience in 2382 patients with primary hypercholesterolemia

We assessed pooled safety and lipid-regulating efficacy data from four similarly designed trials of ezetimibe coadministered with statins in 2382 patients with primary hypercholesterolemia. Patients were randomised to one of the following double-blind treatments for 12 weeks: placebo; ezetimibe 10 mg; statin; or statin + ezetimibe. Statin doses tested were 10, 20, 40 mg/day (atorvastatin, simvastatin, pravastatin or lovastatin) or 80 mg/day (atorvastatin, simvastatin). Treatment with ezetimibe + statin led to significantly greater reductions in low-density lipoprotein cholesterol (LDL-C), total cholesterol, triglycerides, non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B and increases in HDL-C, compared to statin alone. At each statin dose, treatment with ezetimibe + statin led to a greater LDL-C reduction compared to the next highest statin monotherapy dose. Ezetimibe + statin had a safety profile similar to statin monotherapy. Coadministration of ezetimibe + statin offers a well-tolerated, highly efficacious new treatment strategy for patients with hypercholesterolemia.

Long-term safety and tolerability profile of ezetimibe and atorvastatin coadministration therapy in patients with primary hypercholesterolaemia

Long-term safety and tolerability of ezetimibe plus atorvastatin (EZE + ATV) coadministration therapy were compared to those of ATV monotherapy in patients with primary hypercholesterolaemia. Upon completion of a 12 week randomised, double-blind, placebo-controlled study comparing EZE 10 mg; ATV 10, 20, 40 or 80 mg; EZE + ATV 10, 20, 40 or 80 mg or placebo, 246 patients were enrolled in a 12-month extension, with reassignment to double-blind EZE 10 mg (n = 201) or matching placebo (n = 45) coadministered daily with open-label ATV 10 mg. At intervals of 6 weeks, patients not at National Cholesterol Education Program Adult Treatment Panel II LDL-C goals were titrated to the next higher ATV dose. Safety evaluations included adverse event (AE) reports and laboratory test results. EZE + ATV and ATV monotherapy groups were similar with regard to incidence of all AEs (71 vs. 67%), treatment-related AEs (22 vs. 27%) and discontinuations due to AEs (9 vs. 7%) or treatment-related AEs (6 vs. 7%), respectively. Neither clinically significant elevations in hepatic transaminases or creatine kinase nor any cases of myopathy or rhabdomyolysis were observed in either group during the extension study. After 6 weeks, EZE + ATV 10mg produced greater reductions in low-density lipoprotein cholesterol (LDL-C; -53 vs. -37%), total cholesterol (TC; -38.8 vs. -26.0%) and triglycerides (TG; -28 vs. -12%) and similar increases in high-density lipoprotein cholesterol (4.6 vs. 4.5%) compared to ATV 10 mg, respectively, and these changes were maintained and significant at 1 year (p < 0.01 for LDL-C, TC and TG). More EZE + ATV patients achieved LDL-C goal than ATV patients at study endpoint (91 vs. 78%, respectively; p = 0.02). Thus, the coadministration of EZE + ATV for 12 months was well tolerated and more efficacious than ATV monotherapy.

Impact of weight loss on the metabolic syndrome

AIM

Individuals with the metabolic syndrome (MS), a clustering of risk factors [triglycerides, glucose, high-density lipoprotein cholesterol, blood pressure (BP), abdominal obesity] defined by the National Cholesterol Education Program (NCEP), are at high risk for coronary heart disease and type 2 diabetes mellitus, and may benefit from aggressive lifestyle modification.

METHODS

We reviewed 1 year of consecutive patients' charts to determine the prevalence of the MS in obese individuals enrolled in a medically supervised rapid weight loss programme, the correlation of weight change with the components of the MS, and response to diet-induced weight loss.

RESULTS

Out of 185 individuals, 125 (68%) met the NCEP definition of the MS. A moderate decrease in weight (6.5%) induced by a very low calorie diet (VLCD) resulted in substantial reductions of systolic (11.1 mmHg) and diastolic (5.8 mmHg) blood pressure (BP), glucose (17 mg/dl), triglycerides (94 mg/dl) and total cholesterol (37 mg/dl) at 4 weeks (all p < 0.001). These improvements were sustained at the end of active weight loss (average 16.7 weeks; total weight loss 15.1%), with further significant reductions in BP and triglycerides. Weight loss was related to the changes in each criterion of the metabolic syndrome.

CONCLUSIONS

The MS is prevalent in two-thirds of obese individuals enrolling in a structured weight loss programme. Moderate weight loss with a VLCD markedly improved all aspects of the MS.

Familial hypercholesterolaemia: optimum treatment strategies

Familial hypercholesterolaemia (FH) is a hereditary metabolic disorder characterised by defects in the low-density lipoprotein (LDL) receptor, elevated LDL cholesterol (LDL-C) levels and an extremely high risk for premature cardiovascular disease. Heterozygous FH occurs in about one of every 500 individuals in the United States and Europe. The high prevalence of FH and associated morbidity and mortality strongly support aggressive screening and treatment. There are two major barriers to effective management of FH: 1) the failure to screen for this disease in people who may be at increased risk for it; and 2) the inability of most available therapies to enable achievement of LDL-C goals. More aggressive screening, coupled with new genetic screening techniques, and more powerful 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have the potential to overcome these limitations. Automated genetic assays are now available for detection of common LDL receptor mutations in individuals at risk for FH, and they have been used effectively to identify patients with this condition. Recent clinical trial results with the new synthetic statin rosuvastatin (Crestor; AstraZeneca, Alderley Park, Macclesfield, Cheshire, UK; licensed from Shionogi & Co, Ltd, Osaka, Japan) in patients with heterozygous FH have shown that it decreased LDL-C by 58% and increased high-density lipoprotein cholesterol (HDL-C) by 12%. Rosuvastatin was significantly superior to high-dose atorvastatin in improving these lipid parameters as well as total cholesterol, apolipoprotein (apo) B, apo A-I, and the LDL-C/HDL-C ratio. Thus, new screening tools and medical therapies have the potential to significantly improve management and reduce cardiovascular disease risk for patients with FH.

The evolving role of high-density lipoprotein in reducing cardiovascular risk

In many patients with coronary artery disease, a low level of high-density lipoprotein cholesterol (HDL-C), rather than substantially elevated low-density lipoprotein cholesterol (LDL-C), is often the predominant lipid abnormality. Although the National Cholesterol Education Program treatment guidelines include HDL-C concentration as a major risk factor for primary prevention, the guidelines' emphasis on LDL-C as the primary target of therapy may cause uncertainty as to whether risk reduction strategies should focus on lowering LDL-C or raising HDL-C in high-risk patients with low HDL-C. Recent clinical trial evidence and epidemiologic data suggest that HDL-C should play a more important role in risk assessment, and that the definition of low HDL-C may need adjustment from the current National Cholesterol Education Program definition of <35 mg/dL to perhaps <40 mg/dL in men and <45 mg/dL in women. Patients with low HDL-C should receive aggressive risk factor modification, and more emphasis on increasing HDL-C may be warranted in addition to lowering LDL-C. (c) 2001 by CHF, Inc.

Influence of low high-density lipoprotein cholesterol and elevated triglyceride on coronary heart disease events and response to simvastatin therapy in 4S

BACKGROUND

Patients with low HDL cholesterol (HDL-C) and elevated triglyceride had an increased risk for coronary heart disease (CHD) events and received the greatest benefit with fibrate therapy in substudy analyses of the Helsinki Heart Study and the Bezafibrate Infarction Prevention Study.

METHODS AND RESULTS

In this post hoc analysis of the Scandinavian Simvastatin Survival Study, which enrolled patients with elevated LDL cholesterol (LDL-C) and CHD, subgroups defined by HDL-C and triglyceride quartiles were compared to examine the influence of HDL-C and triglyceride on CHD events and response to therapy. Patients in the lowest HDL-C (<1.00 mmol/L [39 mg/dL]) and highest triglyceride (>1.80 mmol/L [159 mg/dL]) quartiles (lipid triad; n=458) had increased proportions of other features of the metabolic syndrome (increased body mass index, hypertension, diabetes), men, prior myocardial infarction, prior revascularization, and beta-blocker use than patients in the highest HDL-C (>1.34 mmol/L [52 mg/dL]) and lowest triglyceride (<1.11 mmol/L [98 mg/dL]) quartiles (isolated LDL-C elevation; n=545). The major coronary event rate was highest in lipid triad patients on placebo (35.9%), and this subgroup had the greatest event reduction (relative risk 0.48, 95% CI 0.33 to 0.69); a significant treatment-by-subgroup interaction (P=0.03) indicated a greater treatment effect in the lipid triad subgroup than the isolated LDL-C elevation subgroup.

CONCLUSIONS

Patients with elevated LDL-C, low HDL-C, and elevated triglycerides were more likely than patients with isolated LDL-C elevation to have other characteristics of the metabolic syndrome, had increased risk for CHD events on placebo, and received greater benefit with simvastatin therapy.

Effect of sirolimus on the metabolism of apoB100- containing lipoproteins in renal transplant patients

BACKGROUND

Sirolimus (Rapamune, rapamycin, RAPA) is a potent immunosuppressive drug that has reduced the rate of acute rejection episodes by more than 40% in phase III trials when added to an immunosuppression regimen of cyclosporine (CsA) and prednisone. However, RAPA treatment tends to increase lipid levels, particularly among patients with pre-existing hyperlipidemia.

METHODS

To identify the metabolic pathway(s) leading to RAPA-mediated hyperlipidemia, five patients with renal transplants maintained on CsA+/-prednisone+/- azathioprine (AZA) were studied before and after 6 weeks of treatment with RAPA (off RAPA and on RAPA, respectively). Each study patient was infused with a single bolus of [2H4]-lysine to derive metabolic parameters for apoB100-containing lipoproteins by using kinetic analysis based upon quantitation of isotopic enrichment by gas chromatography-mass spectrometry.

RESULTS

Serial lipid measurements revealed that four patients displayed increased plasma triglyceride levels after RAPA treatment, which coincided with significantly higher plasma VLDL-apoB100 concentrations (21.7+/-12.1 mg/dl off RAPA vs. 38.7+/-14.8 mg/dl on RAPA, mean+/-SD, P<0.05). Kinetic analysis showed that the RAPA-induced increase in VLDL-apoB100 concentrations was due to a significant reduction in the fractional catabolic rate (FCR) of very low-density lipoprotein (VLDL) apoB100 (0.83+/-0.65 off RAPA vs. 0.24+/-0.10 on RAPA, mean+/-SD, P<0.05), rather than an enhanced VLDL-apoB100 synthesis. In one patient, RAPA treatment induced hypercholesterolemia but not hypertriglyceridemia. This hypercholesterolemia was due to elevated low-density lipoprotein (LDL) cholesterol levels, which coincided with a decreased FCR of LDL-apoB100. Heparin-induced lipoprotein lipase activity was significantly lower in the immunosuppressed hyperlipidemic patients than in normolipidemic controls. However, RAPA treatment did not significantly alter basal lipoprotein lipase activity in renal transplant patients in this study.

CONCLUSIONS

This study indicates that for renal transplant patients in whom RAPA treatment induces hyperlipidemia, this effect is the result of reduced catabolism of apoB100-containing lipoproteins.

Coronary heart disease prediction from lipoprotein cholesterol levels, triglycerides, lipoprotein(a), apolipoproteins A-I and B, and HDL density subfractions: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Despite consensus on the need for blood cholesterol reductions to prevent coronary heart disease (CHD), available evidence on optimal cholesterol levels or the added predictive value of additional lipids is sparse.

METHODS AND RESULTS

After 10 years follow-up of 12 339 middle-aged participants free of CHD in the Atherosclerosis Risk in Communities Study (ARIC), 725 CHD events occurred. The lowest incidence was observed in those at the lowest LDL cholesterol (LDL-C) quintile, with medians of 88 mg/dL in women and 95 mg/dL in men, and risk accelerated at higher levels, with relative risks (RRs) for the highest quintile of 2.7 in women and 2.5 in men. LDL-C, HDL-C, lipoprotein(a) [Lp(a)], and in women but not men, triglycerides (TG) were all independent CHD predictors, providing an RR, together with blood pressure, smoking, and diabetes, of 13.5 in women and 4.9 in men. Lp(a) was less significant in blacks than whites. Prediction was not enhanced by HDL-C density subfractions or apolipoproteins (apo) A-I or B. Despite strong univariate associations, apoB did not contribute to risk prediction in subgroups with elevated TG, with lower LDL-C, or with high apoB relative to LDL-C.

CONCLUSIONS

Optimal LDL-C values are <100 mg/dL in both women and men. LDL-C, HDL-C, TG, and Lp(a), without additional apolipoproteins or lipid subfractions, provide substantial CHD prediction, with much higher RR in women than men.

Achieving and maintaining National Cholesterol Education Program low-density lipoprotein cholesterol goals with five statins

PURPOSE

Most patients fail to achieve and maintain low-density lipoprotein (LDL) cholesterol goals established by the National Cholesterol Education Program (NCEP). The Atorvastatin Comparative Cholesterol Efficacy and Safety Study (ACCESS) was a randomized study comparing the efficacy and safety of five statins and their ability reduce LDL cholesterol to the NCEP target level.

SUBJECTS AND METHODS

Of 7542 patients screened, 3916 hypercholesterolemic patients were randomly assigned to treatment with a statin, beginning with the lowest recommended dose (atorvastatin, pravastatin, and simvastatin, 10 mg; fluvastatin and lovastatin, 20 mg). If the NCEP target was not achieved, the dose was titrated up to the recommended maximum (atorvastatin, fluvastatin, and lovastatin, 80 mg; pravastatin and simvastatin, 40 mg). The total duration of treatment was 54 weeks.

RESULTS

Atorvastatin achieved the greatest mean reduction in LDL cholesterol: 36% +/- 11% at 6 weeks (initial dose) and 42% +/- 13% at 54 weeks. More patients receiving atorvastatin at its initial dose (53%, 997 of 1888) achieved their NCEP target levels than patients receiving simvastatin (38%, 174 of 462), lovastatin (28%, 134 of 472), pravastatin (15%, 71 of 461), or fluvastatin (15%, 69 of 474) at the initial dose. Atorvastatin-treated patients were more likely to maintain their target levels from week 6 to week 54. The percent reduction in LDL cholesterol achieved at the initial dose correlated strongly with the proportion of patients who maintained their goals at 54 weeks (r = -0.84).

CONCLUSION

For patients treated with statins, providing a greater margin between the NCEP target level and the achieved LDL cholesterol level enhances the likelihood of maintaining NCEP goal levels.

Correlation of non-high-density lipoprotein cholesterol with apolipoprotein B: effect of 5 hydroxymethylglutaryl coenzyme A reductase inhibitors on non-high-density lipoprotein cholesterol levels

Apolipoprotein B has been shown to be a better predictor of coronary heart disease than low-density lipoprotein (LDL) cholesterol, and non-high-density lipoprotein (non-HDL) cholesterol may also be a better parameter for coronary heart disease risk assessment and as a target for therapy. Data from the Atorvastatin Comparative Cholesterol Efficacy and Safety Study (ACCESS) were used to assess the correlation between lipid and apolipoprotein B levels before and after lipid-lowering therapy and to examine the effects of 5 hydroxymethylglutaryl coenzyme A reductase inhibitors on lipids and apolipoprotein B. The 54-week study randomized 3,916 hypercholesterolemic patients to atorvastatin, fluvastatin, lovastatin, pravastatin, or simvastatin, initiated at recommended starting doses with titrations as needed at weeks 6, 12, and 18 to achieve National Cholesterol Education Program LDL targets. Compared with LDL cholesterol, non-HDL cholesterol correlated better with apolipoprotein B levels at baseline (r = 0.914, p <0.0001) and at week 54 (r = 0.938, p <0.0001), and the correlation was strong across all baseline triglyceride strata. At starting doses, atorvastatin (10 mg) lowered non-HDL cholesterol by 33.3% compared with 26.6% with simvastatin (10 mg), 24.1% with lovastatin (20 mg), 17.2% with fluvastatin (20 mg), and 17.0% with pravastatin (10 mg). Atorvastatin also provided greater reductions in non-HDL cholesterol after dose titration, and a greater percentage of patients taking atorvastatin achieved non-HDL cholesterol targets. Baseline triglyceride did not affect non-HDL cholesterol reductions with any of the 5 hydroxymethylglutaryl coenzyme A reductase inhibitors. Fewer patients achieved non-HDL cholesterol targets than LDL cholesterol targets, particularly among high-risk patients, implying that if non-HDL cholesterol was used as a target for treatment, more patients would need to be treated more aggressively than National Cholesterol Education Program guidelines require.

Novel polymorphisms in promoter region of atp binding cassette transporter gene and plasma lipids, severity, progression, and regression of coronary atherosclerosis and response to therapy

Identification of mutations in the ATP binding cassette transporter (ABCA1) gene in patients with Tangier disease, who exhibit reduced HDL cholesterol (HDL-C) and apolipoprotein A1 (apoA1) levels and premature coronary atherosclerosis, has led to the hypothesis that common polymorphisms in the ABCA1 gene could determine HDL-C and apoA1 levels and the risk of coronary atherosclerosis in the general population. We sequenced a 660-bp 5' fragment of the ABCA1 gene in 24 subjects and identified 3 novel polymorphisms: -477C/T, -419A/C, and -320G/C. We developed assays, genotyped 372 participants in the prospective Lipoprotein Coronary Atherosclerosis Study (LCAS), and determined the association of the variants with fasting plasma lipids and indices of quantitative coronary angiograms obtained at baseline and 2.5 years after randomization to fluvastatin or placebo. Distribution of -477C/T and -320G/C genotypes were 127 CC, 171 CT, and 74 TT and 130 GG, 168 GC, and 75 CC, respectively, and were in complete linkage disequilibrium (P<0.0001). Data for -477C/T are presented. The -419A/C variant was uncommon (present in 1 of 63 subjects). Heterozygous subjects had a modest reduction in HDL-C (P=0.09) and apoA1 (P=0.05) levels and a lesser response of apoA1 to treatment with fluvastatin (P=0.04). The mean number of coronary lesions causing 30% to 75% diameter stenosis was greater in subjects with the TT genotype (3.1+/-2.1) or CT genotype (2.9+/-1.9) than in subjects with the CC genotype (2.2+/-1.8) (P=0.002). Similarly, compared with subjects with the CC genotype, greater numbers of subjects with the TT or CT genotype had >/=1 coronary lesion (P=0.001). No association between the genotypes and progression of coronary atherosclerosis or clinical events was detected. We conclude that ABCA1 genotypes are potential risk factors for coronary atherosclerosis in the general population.

A prospective study of genetic markers of susceptibility to infection and inflammation, and the severity, progression, and regression of coronary atherosclerosis and its response to therapy

Inflammation plays a key role in susceptibility to coronary atherosclerosis and response to therapy. A diverse array of factors modulates inflammation, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and CD14 receptors on the surface of macrophages. Genes encoding for inflammatory markers have variants that regulate their expression and are potential risk factors for atherosclerosis. We prospectively analyzed the possible association of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C variants, located in the promoter regions, with the severity, progression, and response to therapy of coronary atherosclerosis in a well-characterized cohort. We studied 375 subjects enrolled in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping. Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo. Distributions of genotypes were--for CD14: 100 CC, 184 CT, and 86 TT; IL-6: 152 GG, 153 GC, and 62 CC; and TNF-alpha: 244 GG, 110 GA, and 17 AA. The CD14 CC genotype was associated with incidence of new coronary occlusion (P=0.026); TNF-alpha AA genotype with history of myocardial infarction (MI, P=0.04), and A allele with total occlusions at baseline (P=0.027), and systolic blood pressure (P=0.046); and IL-6-174 CC genotype with baseline minimum lumen diameter (P=0.043) and reduction in lipoprotein(a) with fluvastatin (P=0.03). Otherwise, no association between the genotypes and the biochemical, angiographic, and clinical phenotypes was detected, and neither were genotype-treatment interactions. Functional variants of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C, implicated in the susceptibility to infection, are unlikely to confer major risk for susceptibility to coronary atherosclerosis and its progression or response to therapy in the LCAS population.

The differential roles of LFA-1 and Mac-1 in host defense against systemic infection with Streptococcus pneumoniae

Mice deficient in CD18, which lack all four CD11 integrins, have leukocytosis and increased susceptibility to bacterial infection. To determine the effect of deficiencies in LFA-1 (CD11a/CD18) or Mac-1 (CD11b/CD18) on host defense against systemic bacterial infection, knockout mice were inoculated i.p. with Streptococcus pneumoniae. Increased mortality occurred in both LFA-1(-/-) (15 of 17 vs 13 of 35 in wild type (WT), p < 0.01) and Mac-1(-/-) (17 of 34 vs 6 of 25, p < 0.01) mice. All deaths in LFA-1(-/-) mice occurred after 72 h, whereas most deaths in Mac-1(-/-) mice occurred within 24-48 h. At 24 h, 21 of 27 Mac-1(-/-) mice were bacteremic, vs 15 of 25 WT (p = 0.05); no difference was observed between LFA-1(-/-) and WT. Increased bacteria were recovered from Mac-1(-/-) spleens at 2 h (p = 0.03) and 6 h (p = 0.002) and from livers (p = 0.001) by 6 h. No difference was observed at 2 h in LFA-1(-/-) mice, but by 6 h increased bacteria were recovered from spleens (p = 0.008) and livers (p = 0.04). Baseline and peak leukocyte counts were similar between Mac-1(-/-) and WT, but elevated in LFA-1(-/-). At 8 h, peritoneal neutrophils were increased in Mac-1(-/-), but not significantly different in LFA-1(-/-). Histopathologically, at 24 h Mac-1(-/-) animals had bacteremia and lymphoid depletion, consistent with sepsis. LFA-1(-/-) mice had increased incidence of otitis media and meningitis/encephalitis vs WT at 72 and 96 h. Both Mac-1 and LFA-1 play important but distinct roles in host defense to S. pneumoniae.

Surrogate endpoints and newer risk markers in atherosclerosis management

Trials with clinical events as the primary endpoint inherently have poor sensitivity to detect therapeutic effects on plaque stabilization and thrombosis because most plaques that rupture do not cause symptoms. Blood tests or imaging modalities that correlate to the burden or activity of atherosclerosis may provide surrogate endpoints to assess therapeutic efficacy in both clinical trials and clinical practice. For surrogate endpoints to be valid in clinical trials, they must be biologically plausible (i.e., related to the disease process) and altered by therapies that decrease the endpoint for which they are used as a substitute. Examples of surrogate endpoints include progression of coronary disease assessed by angiography, intravascular ultrasound, and other imaging techniques. Risk assessment may be refined and therapy better monitored with blood tests that measure novel markers of atherosclerotic disease. Markers that have been shown to be associated with atherosclerosis include C-reactive protein, intercellular adhesion molecule 1, interleukin-6, and fibrinogen.

Case 4: type 2 diabetes, hypertension, and dyslipidemia

Patients at risk for coronary heart disease often have multiple underlying risk factors, including hypertension, type 2 diabetes mellitus, and dyslipidemia. The focus of this month's CME case study is recognition of these often silent and coexisting diseases, and the selection of appropriate therapy that will not adversely affect management of comorbid conditions.

A prospective study of paraoxonase gene Q/R192 polymorphism and severity, progression and regression of coronary atherosclerosis, plasma lipid levels, clinical events and response to fluvastatin

Human serum paraoxonase (PON1) is a high-density lipoprotein (HDL)-associated enzyme that is responsible for the protective effect of HDL against oxidation of low-density lipoprotein (LDL). PON1 has a Glu to Arg polymorphism at codon 192 (CGA-->CAA) which is designated R/Q192. The R/Q192 polymorphism has been associated with coronary artery disease (CAD) in several, but not all, case-control studies. We prospectively studied the association of the Q/R192 genotypes with the severity, progression and regression of CAD, plasma lipid levels, clinical events and response to treatment with fluvastatin in a well-characterized cohort. Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping with AlwI enzyme in 356 subjects in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Fasting plasma lipids were measured and quantitative coronary angiograms were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo. A total of 177 (50%), 142 (40%) and 37 (10%) subjects had Q/Q, Q/R and R/R genotypes, respectively. Baseline and final plasma levels of HDL, LDL, triglyceride and other lipoproteins, lesion-specific minimum lumen diameters (MLD), mean MLD, number of coronary lesions and total occlusions at baseline and follow-up and clinical event rates were not significantly different among the genotypes. There was no genotype-treatment interaction with respect to plasma lipid levels and angiographic indices of CAD. The Q/R192 variants of PON1 are not associated with severity, progression or regression of coronary atherosclerosis, plasma lipid levels, clinical events, or response to treatment with fluvastatin. Thus, the Q/R192 polymorphism is not a major risk factor in susceptibility to CAD in the LCAS population.

Efficacy and tolerability of fluvastatin extended-release delivery system: a pooled analysis

BACKGROUND

At high doses, the pharmacokinetics of fluvastatin immediate-release (IR) are nonlinear, possibly due to saturation of hepatic uptake. Fluvastatin delivery to the liver in a slower but sustained fashion would be expected to avoid hepatic saturation without elevating systemic drug levels.

OBJECTIVE

This pooled analysis compared the efficacy and tolerability of extended-release (XL) 80-mg and IR 40-mg formulations of fluvastatin in lowering low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels and raising high-density lipoprotein cholesterol (HDL-C) levels in patients with hypercholesterolemia.

METHODS

Data were pooled from 3 double-blind, randomized, active-controlled, multicenter, parallel-group studies that compared changes in lipid and apolipoprotein levels with fluvastatin XL 80 mg at bedtime (HS) with changes in fluvastatin IR 40 mg HS or BID in patients aged > or =18 years with primary hypercholesterolemia (consistently elevated LDL-C level [> or =160 mg/dL] and plasma TG levels < or =400 mg/dL). The primary efficacy variable was percent change in LDL-C from baseline.

RESULTS

The pooled analysis provided an intent-to-treat efficacy study population of 1674 patients. At 4 weeks, fluvastatin XL 80 mg HS reduced LDL-C levels by a mean of 36.3% (median 38%), significantly greater than a mean reduction of 25.9% (median 27%) seen with fluvastatin IR 40 mg HS, and an incremental additional mean reduction in LDL-C of 10.4% (P < 0.001). At 4 and 24 weeks, fluvastatin XL 80 mg HS provided an LDL-C reduction equivalent to fluvastatin IR 40 mg BID (P < 0.001 for noninferiority). Significant, dose-related changes in HDL-C, LDL-C:HDL-C ratio, total cholesterol, TG, and apolipoprotein A-I and apolipoprotein B levels also occurred. Mean HDL-C level increased by 8.7% and median TG level decreased by 19% with fluvastatin XL 80 mg HS (P < 0.001 and P < 0.05 vs fluvastatin IR 40 mg HS, respectively). Maximum mean increases in HDL-C level (21%) and median decreases in TG level (31%) with fluvastatin XL 80 mg HS occurred in patients with type IIb dyslipidemia and the highest baseline TG. Adverse events were mild, with similar frequency in all treatment groups.

CONCLUSIONS

Once-daily administration of fluvastatin XL 80 mg provides enhanced efficacy with an additional 10.4% reduction in LDL-C levels compared with fluvastatin IR 40 mg HS, and superior increases in HDL-C levels, particularly in patients with elevated TG levels (P < 0.05 vs fluvastatin IR 40 mg HS). Fluvastatin XL 80 mg HS has a good tolerability profile and is effective as starting and maintenance lipid-lowering treatment in patients with type II hypercholesterolemia.

Leukocyte trafficking and myocardial reperfusion injury in ICAM-1/P-selectin-knockout mice

P-selectin and intercellular adhesion molecule-1 (ICAM-1) mediate early interaction and adhesion of neutrophils to coronary endothelial cells and myocytes after myocardial ischemia and reperfusion. In the present study, we examined the physiological consequences of genetic deletions of ICAM-1 and P-selectin in mice. In wild-type mice, after 1 h of ischemia followed by reperfusion, neutrophil influx into the area of ischemia was increased by 3 h with a peak at 24 h and a decline by 72 h. ICAM-1/P-selectin-deficient mice showed a significant reduction in neutrophils by immunohistochemistry or by myeloperoxidase activity at 24 h but no significant difference at 3 h. Infarct size (area of necrosis/area at risk) assessed 24 h after reperfusion was not different between wild-type and deficient mice after 30 min and 1 h of occlusion. Mice with a deficiency in both ICAM-1 and P-selectin have impaired neutrophil trafficking without a difference in infarct size due to myocardial ischemia-reperfusion.

Apolipoprotein E genotypes and response of plasma lipids and progression-regression of coronary atherosclerosis to lipid-lowering drug therapy

OBJECTIVES

We sought to examine the association of apolipoprotein (apo) E genotypes with baseline plasma lipid levels and severity of coronary artery disease (CAD), as well as the response to treatment with fluvastatin in the Lipoprotein and Coronary Atherosclerosis Study (LCAS).

BACKGROUND

Apo E genotypes have been associated with plasma lipid levels and CAD. However, the influence of apo E genotypes on the response of plasma lipids and CAD progression or regression to statin treatment in patients with mildly to moderately elevated cholesterol remains unknown.

METHODS

Apo E genotypes were determined by polymerase chain reaction and restriction mapping. Plasma lipids were measured at baseline and 12 weeks after therapy with fluvastatin or placebo in 320 subjects. In 287 subjects, quantitative coronary angiography was performed at baseline and after 2.5 years of treatment.

RESULTS

Subjects with the 3/3 genotype had greater reductions in total cholesterol (20.4% vs. 15.4%, p = 0.01) and low density lipoprotein (LDL) cholesterol (28.8% vs. 22.7%, p = 0.03) than did the subjects with the 3/4 or 4/4 genotype. In contrast, subjects with the 2/3 genotype (n = 10) had a greater increase in high density lipoprotein cholesterol (19.1%) than did the subjects with the 3/3 genotype (4.3%, p = 0.002) and those with the 3/4 or 4/4 genotype (7.0%, p = 0.02). Subjects with the 3/4 or 4/4 genotype had an increased frequency of previous angioplasty, but other measures of baseline CAD severity and baseline lipids did not differ significantly among the genotypes, nor did CAD progression or clinical events.

CONCLUSIONS

Although subjects with the epsilon4 allele had less reduction in LDL cholesterol with fluvastatin, they had similar benefit in terms of CAD progression.

Efficacy and safety of an extended-release formulation of fluvastatin for once-daily treatment of primary hypercholesterolemia

An extended-release (ER) formulation of fluvastatin 80 mg has been developed for once-daily treatment of primary hypercholesterolemia in patients who require fluvastatin dosages of > 40 mg/day. The study aimed to determine the efficacy and safety of the new formulation and to assess the dose response over the range of 40 to 160 mg/day. After a 4-week placebo/dietary run-in period, 123 patients with primary hypercholesterolemia (Fredrickson type IIa/IIb) were randomized to receive fluvastatin 40, 80, or 160 mg/day for 6 weeks. The 40 mg/day dosage was administered as the marketed immediate-release (IR) capsule and the 80 mg/day dosage as 1 80-mg ER tablet. Patients receiving 160 mg/day were administered 80 mg/day (1 ER tablet) for the first 2 weeks, followed by 160 mg/day (2 ER tablets) for the remainder of the study. All doses were administered once daily at bedtime. The results showed a linear dose-response relation. Doubling the fluvastatin dosage resulted in a 6% greater mean percent reduction in low-density lipoprotein cholesterol (40 mg IR -29%; 80 mg ER -35%; 160 mg ER -41%). In the 160-mg ER group, 62% of patients achieved > or = 40% reductions in low-density lipoprotein cholesterol compared with 32% and 10% of patients in the 80-mg ER and 40-mg IR groups, respectively. Dose ordering of the response was also observed for the other lipid parameters. Fluvastatin ER was well tolerated. Thus, the new ER formulation of fluvastatin was effective and well tolerated in the once-daily treatment of primary hypercholesterolemia.

Mechanism of chronic obstructive uropathy: increased expression of apoptosis-promoting molecules

BACKGROUND

We have demonstrated that renal tubular and interstitial cells undergo pronounced apoptosis during the course of chronic obstructive uropathy (COU). Apoptosis is a complex cellular process consisting of multiple steps, each of which is mediated by families of related molecules. These families may include receptor/ligand molecules such as Fas, Fas ligand, tumor necrosis factor receptor-1 (TNFR-1), and TNF-related apoptosis inducing ligand (TRAIL); signal transduction adapter molecules such as Fas-associated death domain (FADD), TNFR-1 associated death domain (TRADD), receptor-interacting protein (RIP), Fas-associated factor (FAF), and Fas-associated phosphatase (FAP); or effector molecules such as caspases. However, the mechanism of tubular cell apoptosis, as well as the pathogenetic relevance of these apoptosis-related molecules in COU, remains poorly understood.

METHODS

Kidneys were harvested from sham-operated control mice and mice with COU created by left ureter ligation sacrificed in groups of three at days 4, 15, 30, and 45. To detect apoptotic tubular and interstitial cells, in situ end labeling of fragmented DNA was performed. To detect the expression of apoptosis-related molecules, ribonuclease protection assay was used with specific antisense RNA probes for Fas, Fas ligand, TNFR-1, TRAIL, FADD, TRADD, RIP, FAF, FAP, and caspase-8. Immunostaining for Fas, Fas ligand, TRAIL, TRADD, RIP, and caspase-8 was also performed. To assess the role of these molecules in COU-associated renal cell apoptosis, the frequencies of apoptotic tubular and interstitial cells were separately quantitated for each experimental time point, and their patterns of variation were correlated with those of apoptosis-related molecules.

RESULTS

The obstructed kidneys displayed increased apoptosis of both tubular and interstitial cells. Tubular cell apoptosis appeared at day 4 after ureter ligation, peaked (fivefold of control) at day 15, and decreased gradually until the end of the experiment. In contrast, interstitial cell apoptosis sustained a progressive increase throughout the experiment. Apoptosis was minimal at all experimental time points for control and contralateral kidneys. Compared with control and contralateral kidneys, the ligated kidneys displayed a dynamic expression of mRNAs for many apoptosis-related molecules, which included an up to threefold increase for Fas, Fas ligand, TNF-R1, TRAIL, TRADD, RIP, and caspase-8, and an up to twofold increase for FADD and FAP, but there was little change for FAF. These mRNAs increased between days 4 and 15, decreased until day 30, but then increased again until day 45. The rise and fall of mRNAs between days 4 and 30 paralleled a similar fluctuation in tubular cell apoptosis in that period. The subsequent increase of mRNAs was correlated with a continuous rise of interstitial cell apoptosis. We demonstrated a positive immunostaining for Fas and Fas ligand in the tubular cells at early time points as well as in interstitial inflammatory cells at later time points. Although increased expression of TRAIL, TRADD, RIP, and caspase-8 was noted in tubular cells, there was no staining for these molecules in interstitial cells.

CONCLUSION

The current study documents a dynamic expression of several molecules that are known to mediate the most crucial steps of apoptosis. It implicates these molecules in COU-associated renal cell apoptosis and in the pathogenesis of this condition. It also lays the foundation for interventional studies, including genetic engineering, to evaluate the molecular control of apoptosis associated with COU.

IL-10 is induced in the reperfused myocardium and may modulate the reaction to injury

Reperfusion of the ischemic myocardium is associated with a dramatic inflammatory response leading to TNF-alpha release, IL-6 induction, and subsequent neutrophil-mediated cytotoxic injury. Because inflammation is also an important factor in cardiac repair, we hypothesized the presence of components of the inflammatory reaction with a possible role in suppressing acute injury. Thus, we investigated the role of IL-10, an anti-inflammatory cytokine capable of modulating extracellular matrix biosynthesis, following an experimental canine myocardial infarction. Using our canine model of myocardial ischemia and reperfusion, we demonstrated significant up-regulation of IL-10 mRNA and protein in the ischemic and reperfused myocardium. IL-10 expression was first detected at 5 h and peaked following 96-120 h of reperfusion. In contrast, IL-4 and IL-13, also associated with suppression of acute inflammation and macrophage deactivation, were not expressed. In the ischemic canine heart, CD5-positive lymphocytes were the predominant source of IL-10 in the myocardial infarct. In the absence of reperfusion, no significant induction of IL-10 mRNA was noted. In addition, IL-12, a Th1-related cytokine associated with macrophage activation, was not detected in the ischemic myocardium. In vitro experiments demonstrated late postischemic cardiac-lymph-induced tissue inhibitor of metalloproteinases (TIMP)-1 mRNA expression in isolated canine mononuclear cells. This effect was inhibited when the incubation contained a neutralizing Ab to IL-10. Our findings suggest that lymphocytes infiltrating the ischemic and reperfused myocardium express IL-10 and may have a significant role in healing by modulating mononuclear cell phenotype and inducing TIMP-1 expression.

Platelet glycoprotein ibalpha is a counterreceptor for the leukocyte integrin Mac-1 (CD11b/CD18)

The firm adhesion and transplatelet migration of leukocytes on vascular thrombus are both dependent on the interaction of the leukocyte integrin, Mac-1, and a heretofore unknown platelet counterreceptor. Here, we identify the platelet counterreceptor as glycoprotein (GP) Ibalpha, a component of the GP Ib-IX-V complex, the platelet von Willebrand factor (vWf) receptor. THP-1 monocytic cells and transfected cells that express Mac-1 adhered to GP Ibalpha-coated wells. Inhibition studies with monoclonal antibodies or receptor ligands showed that the interaction involves the Mac-1 I domain (homologous to the vWf A1 domain), and the GP Ibalpha leucine-rich repeat and COOH-terminal flanking regions. The specificity of the interaction was confirmed by the finding that neutrophils from wild-type mice, but not from Mac-1-deficient mice, bound to purified GP Ibalpha and to adherent platelets, the latter adhesion being inhibited by pretreatment of the platelets with mocarhagin, a protease that specifically cleaves GP Ibalpha. Finally, immobilized GP Ibalpha supported the rolling and firm adhesion of THP-1 cells under conditions of flow. These observations provide a molecular target for disrupting leukocyte-platelet complexes that promote vascular inflammation in thrombosis, atherosclerosis, and angioplasty-related restenosis.

Leukocyte CD11b expression is not essential for the development of atherosclerosis in mice

CD11b is an alpha chain of the leukocyte beta(2)-integrin, Mac-1, which mediates binding and extravasation of leukocytes. Because this event is critical in atherosclerosis, we examined the role of CD11b in lesion formation. Atherosclerosis-susceptible, low density lipoprotein receptor-deficient (LDL-R(-/)-) mice were irradiated and repopulated with bone marrow cells from CD11b-deficient (CD11b(-/)-) mice. After 4 weeks, <2% of the peripheral blood leukocytes of the CD11b(-/)- bone marrow-transplanted LDL-R(-/)- mice expressed CD11b, whereas approximately 25% of the CD11b(+/)+ bone marrow-transplanted LDL-R(-/)- mice expressed CD11b. After consuming a high-fat diet for 16 weeks the mean lesion aortic valve area, cholesterol accumulation in the aorta, and the degree of intimal macrophage infiltration were similar in mice reconstituted with either CD11b(+)(/+) or CD11b(-/)- bone marrow cells. The studies confirm that CD11b expression of bone marrow-derived cells does not influence the development of atherosclerosis in hypercholesterolemic LDL-R(-/)- mice.

Impact of evidence-based "clinical judgment" on the number of American adults requiring lipid-lowering therapy based on updated NHANES III data. National Health and Nutrition Examination Survey

BACKGROUND

When the National Cholesterol Education Program Adult Treatment Panel II (ATP II) guidelines were published, National Health and Nutrition Examination Survey III data for 1988 to 1991 were used to estimate the number of Americans requiring lipid-lowering therapy based on ATP II cut points. However, the guidelines recommend using clinical judgment to determine whether to initiate drug therapy in individuals whose low-density lipoprotein cholesterol levels remain above treatment goals with diet therapy but below the initiation level for drug therapy.

METHODS

We analyzed updated (1988-1994) National Health and Nutrition Examination Survey III data, based on a sample of 6796 adults aged 20 years and older, to estimate the numbers of American adults with an elevated low-density lipoprotein cholesterol level and requiring drug therapy using cut points vs clinical judgment as specified in ATP II guidelines.

RESULTS

Assuming a 10% low-density lipoprotein cholesterol reduction with diet, an estimated 10.4 million American adults require drug therapy based on ATP II cut points. If we include individuals for whom the guidelines recommend clinical judgment, the estimate increases to 28.4 million. The largest increase occurs in individuals without known coronary heart disease but with 2 or more risk factors: from 5.5 to 17.5 million. These high-risk individuals have low-density lipoprotein cholesterol concentrations similar to those in patients with coronary heart disease.

CONCLUSIONS

Since the ATP II guidelines were published, clinical judgment has been informed by abundant clinical trial evidence establishing the safety and benefit of lipid-lowering therapy. The large number of individuals at high risk for coronary heart disease emphasizes the need for cost-effective therapy to extend treatment to the greatest number of individuals who may benefit.

A chronic mouse model of myocardial ischemia-reperfusion: essential in cytokine studies

Reperfusion of the ischemic myocardium is associated with a cytokine cascade that reflects a cellular response to injury. We studied this cascade in the mouse and found that acute surgical trauma in sham-operated animals obscured early changes in cytokine induction that occur during myocardial ischemia-reperfusion (MI/R). Therefore, we utilized a new implantable device that allows occlusion and reperfusion of the left anterior descending coronary artery in a closed-chest mouse at any time after instrumentation. Induction of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha mRNA in the whole heart was examined by RNase protection assay and quantitated by Phosphor- Imager. At 3 h after instrumentation, levels of IL-6 mRNA in sham-operated animals increased above those of control naive hearts, whereas this increase did not occur until after 1 day for TNF-alpha mRNA. The surgical trauma led to exaggeration of I/R cytokine induction with greater variance in response. At 3 days and 1 wk after instrumentation, levels of both IL-6 and TNF-alpha mRNA in sham-operated animals were comparable to those of naive hearts and induction responses in I/R were much less variant. We also found that 1 h of ischemia and 2 h of reperfusion at all time points of recovery (i.e., 3 h and 1, 3, and 7 days after instrumentation) led to a significant increase in IL-6 and TNF-alpha mRNA levels. In addition, 3 h of permanent occlusion, which did not induce any mRNA increase after 1 wk postinstrumentation, caused marked upregulation of IL-6 mRNA in an acutely prepared animal. This study of early cytokine responses evoked by MI/R highlights the need for dissipation of acute surgical trauma by using a chronic, closed-chest mouse preparation.

A variant of p22(phox), involved in generation of reactive oxygen species in the vessel wall, is associated with progression of coronary atherosclerosis

A series of pro-oxidant and antioxidant enzymes, such as the NADPH oxidase system, maintain the redox state in the vessel wall. A major component of NADPH oxidase is p22(phox), which is implicated in atherosclerosis. We prospectively studied the association of the histidine (H)(72)-->tyrosine (Y) mutation in p22(phox) with the severity and progression/regression of coronary artery disease (CAD), plasma lipid levels, clinical events, and response to treatment with fluvastatin in a well-characterized population. Genotypes were determined by polymerase chain reaction and restriction digestion with RsaI enzyme in 368 subjects in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years after randomization to fluvastatin or placebo. Subjects with CC genotype (n=157) were identified by the presence of 396-bp and 113-bp products on gel electrophoresis. Those with TT (n=39) were identified by the presence of 316-bp, 113-bp, and 80-bp products, and those with CT (n=172) by the presence of 396-bp, 316-bp, 113-bp, and 80-bp products. Baseline and final plasma levels of lipids and the baseline severity of CAD were not significantly different among the genotypes. In the placebo group, subjects with the mutation had a 3- to 5-fold greater loss in mean minimum lumen diameter (MLD) (TT: -0.15+/-0.15; CT: -0.17+/-0.26; and CC: -0.03+/-0.22 mm; P=0. 006) and lesion-specific MLD (TT: -0.15+/-0.06; CT: -0.18+/-0.03; and CC: -0.06+/-0.03 mm; P=0.038) than those without. Progression was also more (TT: 8/17 [47%]; CT: 35/73 [48%]; and CC: 17/62 [27%]) and regression less (TT: 0/17 [0%]; CT: 1/73 [1%]; and CC: 11/72 [18%]) common in those with the mutation (P=0.002). The C(242)T mutation in p22(phox), involved in maintaining the redox state in the vessel wall, is associated with progression of coronary atherosclerosis in the LCAS population.

Strategies for implementing lipid-lowering therapy: pharmacy-based approach

A multidisciplinary program was designed to improve patient outcomes after an acute coronary event. The primary objective of the program was that lipid-lowering therapy be prescribed at the time of discharge for acute myocardial infarction (AMI) and percutaneous transluminal coronary angioplasty (PTCA) patients. Secondary objectives for this program were (1) a baseline lipid panel within the first 24 hours of admission and (2) documentation of discharge counseling for lipid-lowering therapy in the patient medical record. Improvements were reported for all 3 objectives. For the primary indicator, lipid-lowering therapy prescribed at discharge, the baseline value increased from 40% to 72-81%. The percentage of patients with a lipid panel within 24 hours of admission improved from a baseline of 13% to 38-71%. Overall, 28-77% of patient records contained documentation of lipid-lowering medication counseling after initiation of the program. This information should provide the necessary benchmarking data to maintain competitiveness in the dynamic healthcare environment. Overall, this program provides high-quality, cost-effective health care for the patient with established coronary artery disease.

Quality assessment and lipid management: considerations for computer databases for tracking patients

Improving the quality of lipid management requires an objective assessment of current practice and the ability to monitor whether quality is improved by implementing changes in practice. In a competitive healthcare environment, documentation of quality of care and patient outcomes may be important in securing contracts. It would be almost impossible to perform a meaningful clinical-outcome analysis in a timely fashion without the support of a computerized database. However, evaluating, selecting, and implementing computerized databases can be a daunting task. Before the purchase of a database, the following steps should be performed: (1) consider and prioritize the goals for the computerized database; (2) audit charts to determine whether the existing chart format meets the current guidelines for reimbursement and medical-legal standards; (3) revise the paper chart to improve fulfillment of the goals from step 1; (4) consider the specific clinical environment, including the skill level of personnel using the system, how user-friendly the system is, whether the system is multifunctional, and the costs associated with the software and implementation. We have evaluated 3 types of computerized databases and report their strengths and weaknesses; we also briefly discuss the electronic medical record.