Inflammation, pravastatin, and the risk of coronary events after myocardial infarction in patients with average cholesterol levels. Cholesterol and Recurrent Events (CARE) Investigators

Inflammatory markers and coronary heart disease

PURPOSE OF REVIEW

Despite changes in lifestyle and the use of effective pharmacologic interventions to lower cholesterol levels, coronary heart disease remains the major cause of morbidity and mortality in the developed world. Cholesterol screening fails to identify almost 50% of those individuals who will present with acute coronary syndromes. Recent evidence from laboratory and prospective clinical studies demonstrates that atherosclerosis is not simply a disease of lipid deposition, but rather is an inflammatory process with highly specific cellular and molecular responses. The clinical utility of inflammatory markers has been examined in a variety of atherothrombotic diseases. Because C-reactive protein is highly stable in stored frozen samples, and automated and robust analytical systems for its measurement are available, it has become the most widely examined inflammatory marker.

RECENT FINDINGS

C-reactive protein has consistently been shown to be a useful prognostic indicator in acute coronary syndromes and is a strong predictor of future coronary events in apparently healthy individuals. In addition, C-reactive protein can identify individuals with normal lipid levels who are at increased risk for future coronary events. Because drugs such as aspirin and statins reduce inflammatory risk, C-reactive protein has the potential to guide the use of these therapies in high-risk individuals for primary prevention.

SUMMARY

C-reactive protein may have a role in global risk assessment for primary prevention and in targeting those patients who will benefit from anti-inflammatory therapies. In addition, it may also be a good prognostic indicator in patients with acute coronary syndromes.

Pharmacology of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), including rosuvastatin and pitavastatin

Coronary heart disease (CHD) is the leading cause of morbidity and mortality in the Western world, with hypercholesterolemia as the major risk factor. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors represent the most efficient drugsfor the treatment of hypercholesterolemia. They lower plasma cholesterol due to the inhibition of endogenous cholesterol synthesis in the liverand subsequent increased expression of low-density lipoprotein (LDL) receptors, resulting in an up-regulated catabolic rate for plasma LDL. The beneficial effect of statins on the incidence of CHD was clearly demonstrated in several large-scale clinical trials. Currently, five statins (atorvastatin, fluvastatin, lovastatin, pravastatin, and simvastatin) are available, and two novel compounds (pitavastatin, rosuvastatin) are undergoing clinical investigation. To point out potential mechanisms leading to increased toxicity and to compare the novel statins with the established ones, this article summarizes their pharmacological data since the prevalence of adverse events can be explained at least in part by their pharmacokinetic differences.

Statin therapy improves brachial artery endothelial function in nephrotic syndrome

BACKGROUND

Patients with nephrotic syndrome have impaired endothelial function probably related to dyslipidemia. This study evaluated the effects of statin therapy on dyslipidemia and endothelial function in patients with nephrotic syndrome.

METHODS

A sequential, open-label study of the effects of statins on endothelial dysfunction in 10 nephrotic patients treated with an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II (Ang II) receptor antagonist. Endothelial function was assessed at baseline, after 12 weeks of treatment with statins, and after an 8-week washout. Brachial artery endothelial function was measured as post-ischemic flow-mediated dilation (FMD) using ultrasonography. Endothelium-independent, glyceryl trinitrate-mediated vasodilation (GTNMD) also was measured.

RESULTS

Serum lipids were significantly lower following statin: total cholesterol mean 8.2 +/- 0.4 (standard error) mmol/L versus 5.2 +/- 0.3 mmol/L, triglycerides 2.6 +/- 0.4 mmol/L versus 1.6 +/- 0.2 mmol/L, non-HDL-cholesterol 6.7 +/- 0.4 mmol/L versus 3.7 +/- 0.2 mmol/L (all P < 0.001). There was a trend to an increase in serum albumin (31.0 +/- 1.3 g/L vs. 33.8 +/- 1.5 g/L; P = 0.078) and FMD improved significantly following treatment (3.7 +/- 1.1% vs. 7.0 +/- 0.8%, P < 0.01). After washout, FMD deteriorated significantly to 3.5 +/- 1.4% (P < 0.05) versus week 12 FMD. GTNMD was unchanged. In multivariate regression, reduction in non-high-density lipoprotein (HDL)-cholesterol (beta - 0.736, P = 0.027) and increase in serum albumin (beta 0.723, P = 0.028), but not the on-treatment level of non-HDL-cholesterol, were significant independent predictors of improvement in FMD after adjusting for change in resting brachial artery diameter. Changes in serum lipoprotein and albumin concentrations off treatment were not associated with deterioration in FMD.

CONCLUSION

Statin therapy significantly improves dyslipidemia and brachial artery endothelial function in patients with nephrotic syndrome. Improvement in brachial artery endothelial function may be in part related to a non-lipid effect of statins. The findings also suggest a role for dyslipidemia in endothelial dysfunction and the risk for cardiovascular disease in nephrotic syndrome.

Projected life-expectancy gains with statin therapy for individuals with elevated C-reactive protein levels

OBJECTIVES

We sought to estimate the potential gains in life expectancy achieved with statin therapy for individuals without overt hyperlipidemia but with elevated C-reactive protein (CRP) levels.

BACKGROUND

Persons with low-density lipoprotein (LDL) cholesterol levels below current treatment guidelines and elevated CRP levels are at increased risk of cardiovascular disease and may benefit from statin therapy.

METHODS

We constructed a decision-analytic model to estimate the gains in life expectancy with statin therapy for individuals without overt hyperlipidemia but with elevated CRP levels. The annual risks of myocardial infarction (MI) and stroke, as well as the efficacy of statin therapy, were based on evidence from randomized trials. Estimates of prognosis after MI or stroke were derived from population-based studies.

RESULTS

We estimated that 58-year-old men and women with CRP levels >or=0.16 mg/dl but LDL cholesterol <149 mg/dl would gain 6.6 months and 6.4 months of life expectancy, respectively, with statin therapy. These gains were similar to those for patients with LDL cholesterol >or=149 mg/dl (6.7 months for men and 6.6 months for women). In sensitivity analyses, we identified the baseline risk of MI and the efficacy of statin therapy for preventing MI as the most important factors in determining the magnitude of benefit with statin therapy.

CONCLUSIONS

Our results suggest that individuals with elevated CRP levels, many of whom do not meet current National Cholesterol Education Program guidelines for drug treatment, may receive a substantial benefit from statin therapy. This analysis supports a crucial need for direct intervention trials aimed at subjects with elevated CRP levels.

High-sensitivity C-reactive protein and cardiovascular risk in patients with coronary heart disease

High-sensitivity C-reactive protein levels have received widespread attention because of a multitude of prospective studies that have shown that high levels of high-sensitivity C-reactive protein identify increased risk of initial cardiovascular events in coronary heart disease patients and increased risk of recurrent cardiac events in patients with stable and unstable angina, patients with acute myocardial infarction, and patients undergoing elective coronary revascularization procedures. In contrast to several other inflammatory markers, high-sensitivity C-reactive protein measurements are standardized and reproducible. The clinical significance of a reliable inflammatory marker includes identification of high-risk individuals, a gauge to monitor the activity of the disease, and a potential therapeutic target to alter the inflammatory component of the disease process. This review focuses on the importance of high-sensitivity C-reactive protein in cardiovascular risk stratification in coronary heart disease patients and discusses several preventive therapies that may reduce cardiovascular risk through reduction in high-sensitivity C-reactive protein.

A comparison of the Framingham and European Society of Cardiology coronary heart disease risk prediction models in the normative aging study

BACKGROUND

A number of prediction models have been developed in an attempt to accurately identify patients at increased risk of a first coronary heart disease event. We sought to determine the ten-year incidence of coronary heart disease events in a healthy cohort with measurable risk factors, and to compare these results with the predicted number of events by use of both the Framingham and European Society of Cardiology risk prediction models.

METHODS

We compared the predicted and observed number of events in 5 risk categories in 1393 subjects aged 30 to 74 years who were enrolled in the Normative Aging Study.

RESULTS

The risk prediction models reliably stratify populations with regards to relative risk of coronary heart disease events and there is reasonable agreement between the 2 models (weighted kappa = 0.46, P <.01). The Framingham model underestimated the absolute risk of coronary heart disease events in the low-risk group, and both risk prediction models overestimated the absolute risk of events in the high- or very-high-risk groups (Framingham c-statistic = 0.60, European Society of Cardiology c-statistic = 0.58).

CONCLUSIONS

Despite simplification, the accuracy of the European model was not significantly different from the Framingham model. But the accuracy of absolute risk prediction, particularly at the extremes of risk, is imperfect. Refinement and validation of these risk prediction models is important because they affect the management of individual patients and the allocation of community resources.

Early use of statins in acute coronary syndromes

This review examines the use of HMG-CoA reductase inhibitor (statin) medications early in the clinical course of acute coronary syndrome. Available data demonstrate that there are clear clinical benefits to this practice. Numerous previous studies have documented the primary and secondary benefits of statins in the prevention of coronary events. Recent trials show that when statins are used during hospital admissions for acute coronary syndrome (ACS), patients experience decreased recurrent myocardial infarction, lower death rates, and fewer repeat hospitalizations for ischemia or revascularization. Several studies suggest that the positive effects of statins on plaque stabilization, inflammation, thrombosis, and endothelial function may be independent of lipid levels. There is also an emerging view that beneficial lipid-lowering with statins in high-risk patients has no lower limit. This information suggests that all patients admitted for ACS should be treated with statins, regardless of cholesterol levels.

Pharmacologic therapy of lipid disorders in the elderly

Older men and women with coronary artery disease, prior stroke, peripheral arterial disease, and extracranial carotid arterial disease with a serum low-density lipoprotein (LDL) cholesterol > 125 mg/dL despite diet should be treated with lipid-lowering drug therapy, preferably with statins, to reduce the serum LDL cholesterol to < 100 mg/dL. If statin drug therapy does not lower the serum LDL cholesterol to < 100 mg/dL in older persons with coronary artery disease, a bile acid binding resin, such as cholestyramine, should be added, since this drug does not increase the incidence of myositis in persons taking statins. The physician should use statins to treat older persons without atherosclerotic cardiovascular disease with a serum LDL cholesterol > or = 160 mg/dL plus one major risk factor, or a serum LDL cholesterol greater than or equal to 130 mg/dL plus a serum high-density lipoprotein (HDL) cholesterol < 50 mg/dL. Gemfibrozil may be useful in reducing the incidence of coronary events in persons with coronary artery disease whose primary lipid abnormality is a low serum HDL cholesterol level. There are no good data supporting treatment of hypertriglyceridemia unassociated with increased LDL cholesterol or decreased HDL cholesterol for prevention of cardiovascular disease.

Statins in the prevention and treatment of Alzheimer disease

Vascular risk factors such as hypertension and hypercholesterolemia during midlife increase the risk for Alzheimer's disease (AD). Treatment of hypercholesterolemia and other vascular risk factors may have great implications in the prevention of AD. Recent findings illustrate that the sterol metabolism in the brain is an active process, well controlled and regulated by 24-hydroxylase, an enzyme that is uniquely expressed in the brain. The use of statins in ischemic heart disease (IHD) has proven to be a phenomenal advance in pharmacological disease prevention and treatment. A growing body of evidence, suggest that statins exhibit additional benefits that are independent of their cholesterol-lowering actions. Statin treatment has also considerable effect in prevention of ischemic stroke. In animal models of ischemic stroke, statins have proven to reduce infarct size through up-regulation of endothelial nitric oxide synthases. Data from recent observational studies have revealed a potential role for statins in prevention of AD. The following review comments the processes leading to dementia including the involvement of cholesterol regulation, cerebral circulation and inflammation in development of dementia. The mechanisms by which statins may be beneficial in controlling these processes is discussed.

C-reactive protein and coronary artery disease: influence of obesity, caloric restriction and weight loss

C reactive protein (CRP) values in blood are a good indicator of the likelihood of acute coronary and cerebral events in both healthy subjects and patients with coronary artery disease. This indicates that atherosclerotic lesions rich in inflammatory cells and cytokines are more likely to produce acute events either through vasospasm and/or thrombosis and also can be readily detected through elevations in CRP when measured using a high sensitivity assay (hsCRP). However the arterial wall is only one potential source of cytokines which induce CRP production. Fat cells also produce cytokines, in particular IL-6 which induces the synthesis of CRP by the liver. Obesity, especially abdominal obesity, is associated with elevations of hsCRP. This may be of pathogenic significance as CRP stimulates the uptake of LDL by macrophages, induces complement activation which may cause cellular damage in the artery, and enhances monocyte production of tissue factor, thus enhancing the risk of thrombosis. Caloric restriction and weight loss lowers IL-6 and CRP levels and may beneficially suppress an immune response. Whether particular dietary macronutrients or micronutrients alter IL-6 or CRP is unknown but this issue is clearly becoming more important.

C-reactive protein, statins, and the primary prevention of atherosclerotic cardiovascular disease

Emerging data implicate inflammation as integral to atherosclerosis and its complications. From a clinical perspective, the inflammatory biomarker C-reactive protein has demonstrated consistent predictive value in the detection of individuals at high risk for cardiovascular disease. Therapy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) reduces C-reactive protein as well as low-density lipoprotein cholesterol, thus providing a potential additional mechanism for the reduction in cardiovascular events associated with the use of these agents. Evidence from the Air Force/Texas Coronary Atherosclerosis Prevention Study suggests that statin therapy may be effective in reducing incident coronary events among those with elevated levels of C-reactive protein but normal levels of low-density lipoprotein cholesterol. These data, along with accumulating laboratory data, support a potential anti-inflammatory benefit of statins. Large-scale, randomized trials in the primary prevention of acute coronary events among individuals without overt hyperlipidemia but with evidence of elevated C-reactive protein are now needed to directly test this hypothesis.

Plasma alpha2-HS glycoprotein concentrations in patients with acute myocardial infarction quantified by a modified ELISA

BACKGROUND

Human alpha2-HS glycoprotein (alpha2-HSG) is synthesized and secreted by the liver into circulation. Plasma concentrations of alpha2-HSG decrease significantly following infection, inflammation and malignancy. Since increased plasma concentrations of C-reactive protein are observed in patients with acute myocardial infarction (AMI), we hypothesized that plasma concentrations of alpha2-HSG would decrease during the initial phase of AMI and begin to increase in the recovery phase.

METHODS

Twenty patients diagnosed with AMI were recruited for the study. A sensitive and specific ELISA was developed to assay alpha2-HSG concentrations in plasma.

RESULTS

In AMI patients, plasma alpha2-HSG concentrations were decreased (281.3+/-25.8 mg/l, ranging from 132 to 489 mg/l on admission) compared to healthy individuals (312.3+/-9.9 mg/l, ranging from 210 to 450 mg/l) (P= 0.142). Interestingly, 40% of AMI patients demonstrated alpha2-HSG concentrations below 200 mg/l compared to none in the healthy control group. During the recovery period, alpha2-HSG concentrations begin to increase, with a mean+/-SEM of 290.1+/-22.1 mg/l. Regression analysis comparing plasma alpha2-HSG concentrations on admission to concentrations on discharge showed a significant positive correlation in matched-pair patient samples (P<0.01, r=0.45).

CONCLUSIONS

We conclude that, in contrast to C-reactive protein, alpha2-HSG functions as a negative acute phase protein in AMI patients. Plasma alpha2-HSG concentrations start to decrease within a few hours after the onset of AMI and return to near normal concentrations during the recovery period (5-7 days after AMI).

Reduced expression of endothelial cell markers after 1 year treatment with simvastatin and atorvastatin in patients with coronary heart disease

The study was aimed at investigating the effects, after treatment for 1 year, of two different statins on the levels of circulating biochemical markers of endothelial function in patients with established coronary heart disease, with the hypothesis that statins might reduce these levels. Twenty-eight patients were randomized to treatment with atorvastatin and 30 to simvastatin for 1 year. The starting dose in both groups was 20 mg/day. Soluble forms of P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were determined to assess inflammatory activity of the endothelium, and tissue plasminogen activator antigen (tPAag), von Willebrand factor and thrombomodulin for evaluation of the haemostatic function. In the total study population there were significantly reduced levels after 1 year treatment in ICAM-1 (P<0.001), E-selectin (P=0.022) and P-selectin (P<0.001), whereas a significant increase was observed in VCAM-1 (P=0.003). Almost the same pattern was seen within both groups although the increase in VCAM-1 was only seen in the simvastatin group (P=0.017). An overall reduction in tPAag was further observed (P=0.048). The reduction in proinflammatory and to some extent haemostatic markers of endothelial function after 1 year treatment with either simvastatin or atorvastatin may be indicative of a less activated state of the endothelium which possibly may contribute to modulation of the progression of atherosclerosis.

Effect of ciprofibrate on C-reactive protein and fibrinogen levels

Statins can lower the circulating levels of C reactive protein (CRP). This effect may be relevant because CRP is a predictor of vascular risk. In contrast, the evidence that fibrates lower CRP levels is very limited. The effect of treatment with ciprofibrate (100 mg once daily) was investigated for 8 weeks in 30 patients with primary dyslipidemia. There was a significant (p < 0.01) decrease in median (range) CRP levels by 36.8% from 1.9 mg/L (1.0-6.0 mg/L) to 1.2 mg/L (1.0-5.5 mg/L). Plasma fibrinogen levels were also significantly (p = 0.05) reduced. There was no correlation between the fall in CRP levels and the changes in lipid or fibrinogen levels. These findings support the concept that fibrates, like the statins, lower serum CRP levels. However, fibrates have a different mode of action. Fibrates (with the exception of gemfibrozil) also consistently lower plasma fibrinogen levels. In contrast, the effect of statins on the circulating levels of this coagulation factor remains to be defined. These differences may help in defining the mechanisms responsible for drug-induced changes in the circulating levels of CRP and fibrinogen. A favorable effect on CRP and fibrinogen levels may increase the clinical efficacy of statins and fibrates.

Multifocal coronary plaque instability

Recent observations document that many patients with acute coronary syndromes harbor multiple complex plaques by angiography, which correlate with multiple plaque ruptures and clots at necropsy. Multifocal plaque instability is evident not only in coronary vessels but also in peripheral vessels where peripheral and coronary plaque instability may exist concomitantly. These observations support the concept that plaque instability is not merely a local vascular accident but instead reflects more systemic pathophysiological processes with potential to destabilize atherosclerotic plaques throughout the cardiovascular system.

C-reactive protein and cardiovascular disease: a review of risk prediction and interventions

BACKGROUND

Coronary vascular disease (CVD) has a high prevalence in the United States, yet 40-50% of those with that diagnosis have normal or mildly increased cholesterol levels. Increased C-reactive protein (CRP) has been associated with CVD, in those presenting after an acute coronary event, and also in apparently healthy individuals.

METHODS

We reviewed the literature on this association, and on the relationship between CRP and traditional CVD risk factors including smoking, hypertension, cholesterol and obesity. Also examined is the effect of various medications used in patients with CVD on CRP concentrations.

RESULTS

CRP correlates with risk of CVD in patients who have a history of acute coronary disease, stable angina, and in those who have never been diagnosed with CVD. CRP imparts risk that is independent of hyperlipidemia.

CONCLUSION

Once commercially available CRP assays are shown to be reliable, CRP may help predict short- and long-term cardiovascular outcomes and may have a role in CVD screening analogous to that of lipid. In the future CRP may modify treatment and preventive therapies.

Severe hypertriglyceridemia with insulin resistance is associated with systemic inflammation: reversal with bezafibrate therapy in a randomized controlled trial

PURPOSE

To determine whether hypertriglyceridemia is associated with systemic inflammation, which may contribute to the increased cardiovascular risk in patients who have hypertriglyceridemia. In addition, we investigated whether fibrates reverse this inflammatory state.

PATIENTS AND METHODS

Serum lipid levels, body mass index, insulin resistance, and inflammatory parameters were compared between 18 patients who had severe hypertriglyceridemia without cardiovascular disease and 20 normolipidemic controls. We measured the ex vivo production capacity of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 after whole-blood stimulation with lipopolysaccharide, as well as circulating levels of C-reactive protein and fibrinogen. A randomized controlled trial was conducted to determine whether bezafibrate (400 mg administered daily for 6 weeks) affected these parameters in hypertriglyceridemic patients.

RESULTS

When compared with normolipidemic controls, hypertriglyceridemic patients had significantly lower high-density lipoprotein (HDL) cholesterol and higher triglyceride levels, body mass index, and insulin resistance. In addition, hypertriglyceridemic patients had a significantly higher production capacity of TNF-alpha (mean difference, 11 700 pg/mL; 95% confidence interval [CI]: 7800 to 15,700 pg/mL]) and IL-6 (mean difference, 20,400 pg/mL; 95% CI: 7800 to 32,900 pg/mL), and higher levels of C-reactive protein (mean difference, 0.8 mg/L; 95% CI: 0.1 to 2.4 mg/L) and fibrinogen (mean difference, 0.8 g/dL; 95% CI: 0.3 to 1.3 g/dL). Bezafibrate therapy significantly increased HDL cholesterol levels, reduced triglyceride and insulin resistance levels, and reduced production capacity of TNF-alpha and IL-6, as well as levels of C-reactive protein and fibrinogen.

CONCLUSION

Systemic inflammation is present in patients who have the clinical phenotype that is associated with severe hypertriglyceridemia, and may contribute to the increased risk of cardiovascular disease in these patients. Bezafibrate has anti-inflammatory effects in these patients.

Interaction of hemostatic genetics with hormone therapy: new insights to explain arterial thrombosis in postmenopausal women

Genetic variants of key hemostatic mediators increasingly have been proposed as risk factors for atherothrombosis. The Hormone and Estrogen/Progestin Replacement Study group recently reported that the initiation of estrogen replacement in postmenopausal women with known coronary heart disease is associated with an early increase in cardiovascular events. A putative genetic susceptibility factor has been proposed a potential mediator of this increased event risk. This review outlines the recent literature to support the premise for this important proposal. Genetic profiling has great potential to improve the safety and efficacy of individualized pharmacotherapy in postmenopausal women and other at-risk populations for the prevention of cardiovascular disease.

Discriminative value of serum amyloid A and other acute-phase proteins for coronary heart disease

We studied the value of serum amyloid A (SAA), a first-class acute-phase protein, as a marker for coronary heart disease (CHD) in a middle-aged male population. In a working population of 16307 men (age, 35-59 years), 446 cases had a history of CHD or prominent Q:QS waves on electrocardiogram. For each case, two matched controls were investigated. SAA, measured by immunonephelometry, was correlated with other acute-phase proteins, cardiovascular risk factors, and infectious serology markers. SAA concentrations were significantly higher in the cases than in controls (P<0.05) and correlated with serum C-reactive protein (CRP) (r=0.61), plasma fibrinogen (r=0.39), serum haptoglobin (r=0.26), and body mass index (r=0.13) (P<0.001). Serum CRP is a better marker for CHD than SAA, which showed discriminative power only in a univariate model comparing highest versus lowest tertile (odds ratio, 1.39; 95% confidence interval, 1.03-1.87). Neither SAA nor other acute-phase proteins correlated with Chlamydia pneumoniae immunoglobulin (Ig)G, Helicobacter pylori IgG and IgA, and cytomegalovirus IgG. In conclusion, although SAA has a discriminative value for CHD, serum CRP is to be preferred as a first-class acute-phase reactant for detection of the disease.

Management After Myocardial Infarction

Individuals who survive an acute myocardial infarction (MI) have up to a ninefold greater risk of cardiovascular morbidity and mortality compared with the general population. The modification of traditional coronary risk factors, including hypertension, hyperlipidemia, tobacco use, and diabetes mellitus, constitutes one of the cornerstones of management after acute MI. Therapies aimed at reversing the pathophysiologic disorders that lead to endothelial dysfunction, thrombosis, and atherosclerotic plaque instability may improve the prognosis for patients after acute MI. Aggressive risk stratification diagnostic testing can identify patients at the highest risk for adverse events. Prior to hospital discharge, patients should have an evaluation of left ventricular systolic function, an assessment for the risk for residual myocardial ischemia, and a clinical assessment of the risk for serious ventricular arrhythmias. An array of pharmaceutical agents is available for the secondary prevention of MI, including antiplatelet agents, beta-blockers, angiotensin-converting enzyme inhibitors, and statins.

Estrogen, statins, and polyunsaturated fatty acids: similarities in their actions and benefits-is there a common link?

OBJECTIVES

To investigate whether there is any common link between estrogen, statins, and polyunsaturated fatty acids (PUFAs), which have similar actions and benefits.

METHODS

To critically review the literature pertaining to the actions of estrogen, statins, and various PUFAs.

RESULTS

Estrogen, statins, and PUFAs enhance nitric oxide synthesis, suppress the production of proinflammatory cytokines such as tumor necrosis factor(alpha), interleukin-1, interleukin-2, and interleukin-6, show antioxidant-like and antiatherosclerotic properties, have neuroprotective actions, and by themselves or their products inhibit tumor cell proliferation and improve osteoporosis. Estrogen, statins, and PUFAs not only have similar actions but also appear to interact with each other. For instance, the binding of estrogen to its receptor on the cell membrane may be determined by its lipid content, statins and PUFAs inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, statins influence the metabolism of PUFAs, and PUFA deficiency enhances 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. Statins and PUFAs inhibit tumor cell proliferation, suppress ras activity, and may prevent neurodegeneration and improve cognitive functions such as learning and memory. This suggests that PUFAs might be mediators of the actions of statins. Estrogen boosts cognitive performance in women after menopause and may protect against Alzheimer's disease.

CONCLUSIONS

The common link between estrogen, statins, and PUFAs may be nitric oxide. Hence, a combination(s) of estrogen or its derivatives, statins, and various PUFAs may form a novel approach in the management of various conditions such as hyperlipidemias, coronary heart disease, atherosclerosis, osteoporosis, cancer, neurodegenerative conditions, and to improve memory.

Usefulness of high-sensitivity C-reactive protein in predicting long-term risk of death or acute myocardial infarction in patients with unstable or stable angina pectoris or acute myocardial infarction

High-sensitivity C-reactive protein (CRP), proposed as a new coronary risk marker, may reflect either an acute phase reaction or the level of chronic inflammation. Thus, CRP may be less predictive of long-term outcomes when measured after acute myocardial infarction (AMI) than after unstable angina pectoris (UAP) or stable angina pectoris (SAP). A total of 1,360 patients with severe coronary artery disease (>/=1 stenosis >/=70%) had CRP levels obtained at angiography. Presenting diagnoses were SAP (n = 599), UAP (n = 442), or AMI (n = 319). During follow-up (mean 2.8 years), death or nonfatal AMI (D/AMI) occurred in 19.5%, 16.1%, and 17.2% (p = NS) with SAP, UAP, and AMI, respectively. Corresponding median CRP levels were 1.31, 1.27, and 2.50 mg/dl (p <0.001). For the overall cohort, increasing age, low ejection fraction, revascularization, and elevated CRP were the strongest of 6 independent predictors for D/AMI. Among those presenting with SAP, CRP levels above the first tertile were associated with an adjusted hazard ratio of 1.8 (95% confidence interval [CI] 1.2 to 2.8, p <0.009) for D/AMI. After UAP, the hazard ratio was 2.7 (95% CI 1.4 to 5.0, p <0.002). However, when measured during hospitalization for AMI, CRP was not predictive of long-term outcome (hazard ratio 1.0 [95 % CI 0.5 to 1.7] p = 0.86). In conclusion, predischarge CRP levels are higher after AMI than after UAP or SAP. However, whereas CRP is strongly predictive of long-term D/AMI for patients presenting with SAP or UAP, it is not predictive shortly after AMI, suggesting that measurements should be delayed until the acute phase reaction is over and levels have returned to baseline.

Lipoprotein changes with statins

The effects of statins and other lipid drugs are assessed by their ability to affect specific lipid fractions. Although there has been a great deal written abut the statins, most recent papers have focused on the comparative effects of the statins on triglycerides and high-density lipoprotein cholesterol, or have been concerned with the nonlipid effects of these drugs. In addition, some recent papers have focused on new parameters that may mediate cardiovascular risk, such as high-sensitivity C-reactive protein.

The role of chemokines in human cardiovascular pathology: enhanced biological insights

A growing body of experimental evidence supports the pivotal role of chemokines in the pathogenesis of vascular disease. The endothelial expression of monocyte chemoattractant protein-1 (MCP-1) is apparently essential for the earliest cellular responses of atherogenesis. Many atherogenic and anti-atherogenic stimuli can be construed to exert their effects predominantly upon MCP-1 expression within the vascular wall. The atherogenic effects of interleukin-8 (IL-8) seem to be mediated through the down-regulation of the tissue inhibitor of metalloproteinase-1 (TIMP-1). Biological expression of these two important vascular chemokines is further modulated by NF-kappaB. The delineation of these molecular forces that drive atherogenesis increasingly underscores the pivotal role of various chemokines. It is anticipated that more precise delineation of these patterns of gene expression will help to identify molecular targets for the prevention and treatment of atherosclerosis.

Statins and inflammatory markers

Inflammation is involved in the initiation and progression of atherosclerosis and the development of atherosclerotic events. Understanding of the molecular basis of inflammation has led to the identification of markers that may be important new targets in atherothrombotic disease. Inflammatory markers, such as cell adhesion molecules, cytokines, and high-sensitivity C-reactive protein, have been shown to predict future cardiovascular events in individuals with and without established disease. 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, or statins, inhibit the synthesis of cholesterol and have been demonstrated to reduce cardiovascular morbidity and mortality. Recently, statins have been shown to modulate several of the mechanisms of inflammation in atherosclerosis in vitro and in vivo, including reduction of inflammatory markers in clinical trials. In this article, we briefly review the biology, epidemiology, and clinical trial data on the effects of statins on some of the more promising inflammatory markers.

Statin therapy, inflammation and recurrent coronary events in patients following coronary stent implantation

OBJECTIVES

We sought to investigate whether statin therapy affects the association between preprocedural C-reactive protein (CRP) levels and the risk for recurrent coronary events in patients undergoing coronary stent implantation.

BACKGROUND

Low-grade inflammation as detected by elevated CRP levels predicts the risk of recurrent coronary events. The effect of inflammation on coronary risk may be attenuated by statin therapy.

METHODS

We investigated a potential interrelation among statin therapy, serum evidence of inflammation, and the risk for recurrent coronary events in 388 consecutive patients undergoing coronary stent implantation. Patients were grouped according to the median CRP level (0.6 mg/dl) and to the presence of statin therapy.

RESULTS

A primary combined end point event occurred significantly more frequently in patients with elevated CRP levels without statin therapy (RR [relative risk] 2.37, 95% CI [confidence interval] [1.3 to 4.2]). Importantly, in the presence of statin therapy, the RR for recurrent events was significantly reduced in the patients with elevated CRP levels (RR 1.27 [0.7 to 2.1]) to about the same degree as in patients with CRP levels below 0.6 mg/dl and who did not receive statin therapy (RR 1.1 [0.8 to 1.3]).

CONCLUSIONS

Statin therapy significantly attenuates the increased risk for major adverse cardiac events in patients with elevated CRP levels undergoing coronary stent implantation, suggesting that statin therapy interferes with the detrimental effects of inflammation on accelerated atherosclerotic disease progression following coronary stenting.

Cardiovascular trials of estrogen replacement therapy

An impressive body of evidence has suggested that estrogen therapy should be helpful to slow the pathogenesis or progression of atherosclerosis. Estrogen's favorable effects on lipids and endothelial function, coupled with extensive observational epidemiology and data from animal models of atherosclerosis, persuaded many that hormone replacement therapy (HRT) would be helpful for both primary and secondary prevention of coronary disease. Recently, several randomized clinical trials of HRT have been completed, and several more are currently under way. These trials include both primary and secondary prevention cohorts and use clinical as well as anatomic manifestations of atherosclerosis as outcomes. These trials are producing surprising and controversial results that will radically alter contemporary understanding of the role of HRT for cardiovascular disease prevention. This review briefly describes the findings of the Heart and Estrogen/Progestin Replacement Study, the Estrogen Replacement and Atherosclerosis Trial, and other recently completed clinical trials. Trials that are under way are also described and discussed.

Markers of the acute phase response in cardiovascular disease: an update

There is now widespread agreement that inflammation is a key component in the progression of atheromatous lesions. Inflammatory cells are present at all stages in the development of the atheromatous plaque, and gene knockout experiments in mice show that atheroma is largely prevented in the absence of the normal inflammatory mediators. In humans reduction of inflammation accompanies successful treatment strategies for atheroma. An increasing number of studies suggest that the acute phase protein, C-reactive protein, provides increased prognostic information over and above existing markers of atheroma severity or progression in healthy individuals and in the acute coronary syndromes. Recent advances in our knowledge of the normal variability of C-reactive protein levels and in precise and sensitive measurements strengthen the arguments for adding this marker to the repertoire of the routine laboratory assessment of cardiovascular disease.

Emerging perspectives on lipid management: international approaches and global challenges

The rapid growth in the understanding of the relation between cholesterol and coronary heart disease has introduced new challenges to the contemporary management of lipid disorders. The publication of the trials of the 3-hydroxy-3-methylglutaryl coenzyme-A inhibitors (statins) has invigorated support for the lipid hypothesis, and many advances have been made in understanding the mechanisms underlying atherosclerosis and the potential benefits of the statins. Several international groups have issued guidelines about desirable and undesirable lipid values to help clinical decision making. Despite the availability of such principles, there are many challenges to optimal management of lipid disorders.

What is the role of intensive cholesterol lowering in the treatment of acute coronary syndromes?

Cholesterol lowering with statins reduces coronary events in a primary-prevention setting and in patients with stable coronary disease. However, where the risk of a coronary event is highest, in the early months after an episode of unstable angina or non-Q-wave infarction, the effect of statin therapy has not been evaluated until recently. The lack of an early benefit in the 3 main statin trials in stable coronary disease may have discouraged this type of investigation. Yet, evidence suggests that intensive cholesterol lowering can rapidly influence several mechanisms intimately related to the pathogenesis of acute coronary syndromes; specifically, improvement in endothelial function, decreased propensity for platelet thrombus formation, and reduced inflammation. Furthermore, 3 nonrandomized, observational studies have recently reported an improved outcome in statin-treated compared with untreated patients after acute coronary syndromes.

The prognostic value of B-type natriuretic peptide in patients with acute coronary syndromes

BACKGROUND

Brain (B-type) natriuretic peptide is a neurohormone synthesized predominantly in ventricular myocardium. Although the circulating level of this neurohormone has been shown to provide independent prognostic information in patients with transmural myocardial infarction, few data are available for patients with acute coronary syndromes in the absence of ST-segment elevation.

METHODS

We measured B-type natriuretic peptide in plasma specimens obtained a mean (+/-SD) of 40+/-20 hours after the onset of ischemic symptoms in 2525 patients from the Orbofiban in Patients with Unstable Coronary Syndromes-Thrombolysis in Myocardial Infarction 16 study.

RESULTS

The base-line level of B-type natriuretic peptide was correlated with the risk of death, heart failure, and myocardial infarction at 30 days and 10 months. The unadjusted rate of death increased in a stepwise fashion among patients in increasing quartiles of base-line B-type natriuretic peptide levels (P< 0.001). This association remained significant in subgroups of patients who had myocardial infarction with ST-segment elevation (P=0.02), patients who had myocardial infarction without ST-segment elevation (P<0.001), and patients who had unstable angina (P<0.001). After adjustment for independent predictors of the long-term risk of death, the odds ratios for death at 10 months in the second, third, and fourth quartiles of B-type natriuretic peptide were 3.8 (95 percent confidence interval, 1.1 to 13.3), 4.0 (95 percent confidence interval, 1.2 to 13.7), and 5.8 (95 percent confidence interval, 1.7 to 19.7). The level of B-type natriuretic peptide was also associated with the risk of new or recurrent myocardial infarction (P=0.01) and new or worsening heart failure (P<0.001) at 10 months.

CONCLUSIONS

A single measurement of B-type natriuretic peptide, obtained in the first few days after the onset of ischemic symptoms, provides powerful information for use in risk stratification across the spectrum of acute coronary syndromes. This finding suggests that cardiac neurohormonal activation may be a unifying feature among patients at high risk for death after acute coronary syndromes.

The role of risk factors in the development of atherosclerosis

Our understanding of risk factors for atherogenesis has changed significantly over the last decade. In addition to better grasp of the mechanism of action of the "classic" (causal) risk factors, a number of potentially important new factors has emerged. In this review we briefly summarize the evidence of the relation between atherosclerosis and the currently recognized causal risk factors, namely, age, smoking, LDL cholesterol, HDL cholesterol, hypertension, and diabetes. More emphasis has been put on description of the emerging entities such as atherogenic profile of plasma lipoproteins with discussion of LDL and HDL subclasses, Lp(a), homocysteine, and, last but not least, on the role of infection and inflammation in atherogenesis. Whenever possible, we tried to summarize the relevant lines of evidence such as epidemiological, pathological, genetic, and clinical trial data linking the specific factor with atherosclerosis.

C-reactive protein and coronary heart disease in western Turkey

C-reactive protein (CRP) has been recognized as a useful marker for coronary or cardiovascular risk in healthy subjects or patients with coronary heart disease (CHD) in industrialized societies. We assessed whether CRP could serve as a marker of prevalent CHD risk in a cross-sectional study of a population with low cholesterol levels (4.61 mmol/L in men and 4.82 mmol/L in women) but higher prevalence of other risk factors. In 1,046 participants of the Turkish Adult Risk Factor Survey in 2000, high-sensitivity CRP as well as other risk variables were evaluated, and CHD was diagnosed, based on clinical findings and Minnesota coding of electrocardiograms at rest. Almost an equal number of men and women > or = 30 years of age constituted the population sample of the western regions of Turkey. Geometric mean value of CRP was 1.9 mg/L (interquartile range 0.8 to 4.3), without revealing a significant difference in gender. CRP was correlated with many variables, notably those involving central obesity, fibrinogen, and apolipoprotein-B, but not with smoking status (regardless of age adjustment). In multiple regression models, blood fibrinogen, waist circumference, total cholesterol, and physical activity grade were independently associated with log CRP concentrations. Among many risk variables, CRP quartiles and systolic blood pressure were, besides age and gender, the only significant independent determinants of CHD. The age-adjusted odds ratio for CHD in the highest as opposed to the lowest quartile was 4.48 (p < 0.001). Even after adjustment for the 5 previously mentioned determinants of CRP, a 4.2-fold increased risk of CHD still persisted between the highest and lowest quartiles. Thus, the observed increased risk was not in large part due to the intermediary effects of fibrinogen, nor were some indicators of insulin resistance, but interaction appeared to be independent of these effects. Thus, CRP values serve as a marker of prevalent CHD risk in populations with low cholesterol levels. This association is independent of, or in addition to, the effects of conventional risk factors, suggesting that the contribution of chronic low-grade inflammation to the atherothrombotic process is present even in the setting of low cholesterol levels.

C-reactive protein and primary prevention of ischemic heart disease

C-reactive protein (CRP) is the prototype acute phase reactant and therefore a marker of systemic inflammation. In the last decades, accumulating data have demonstrated the role of inflammation in the pathogenesis of ischemic heart disease. High CRP levels, measured by high-sensitivity methods, on admission have a short-term negative prognostic value and are associated with a worse outcome. In epidemiological studies, minor elevations of CRP are associated with future risk of myocardial infarction, stroke and peripheral vascular disease. This increased risk is independent of other biochemical and clinical risk factors, and the association between high CRP and an abnormal cholesterol ratio significantly increases the risk in the individual patient. Finally, the observation of an increased level of CRP may be of clinical utility in primary prevention, because these subjects favourably benefit from statin therapy.

C-Reactive Protein and secondary prevention of coronary events

Accumulating data suggest that in ischemic syndromes, the activation of the inflammatory process plays a critical role. C-Reactive Protein (CRP) is a useful marker of inflammation in patients with ischemic heart diseases, particularly unstable angina (UA) and acute myocardial infarction. CRP may separate patients into two groups, one with low CRP levels and low in-hospital risk and one with high CRP levels and high in-hospital risk of major coronary events. When considering risk stratification of patients with acute coronary syndromes, the measurement of CRP seems to add further information to cardiac troponins. The seronegativity of both markers is associated with very low risk of myocardial infarction, while 15% of patients with MI have elevated CRP with negative troponins.

Systemic inflammation as a cardiovascular disease risk factor and as a potential target for drug therapy

Inflammation-related processes play a key role the current etiologic model of atherosclerosis and its acute complications. Recent evidence suggests that blood-based biomarkers that reflect systemic inflammation may contribute to our ability to predict future risk of cardiovascular disease. Global markers of inflammation, such as C-reactive protein and fibrinogen, have been well studied as potential cardiovascular risk factors. A variety of additional markers that reflect various elements of the complex systems governing inflammation, including proinflammatory and antiinflammatory cytokines, mediators of cellular adhesion, and matrix degradation enzymes, are also worthy of study. Although many previous studies have examined the relation of inflammation to myocardial infarction, emerging evidence suggests that other cardiovascular phenotypes such as ischemic stroke and early-stage atherosclerosis may also be related to inflammation. Further elucidating the role of inflammation in cardiovascular disease may lead to the identification of new targets for preventive or therapeutic interventions. In addition, markers of inflammation may be useful as a means to predict or monitor an individual's response to currently available cardiovascular therapies, such as aspirin or HMG coenzyme A reductase inhibitors, that may act via antiinflammatory mechanisms.

Extent of coronary atherosclerosis and homocysteine affect endothelial markers

The aim of the study was to evaluate the effects of the presence, extent, and clinical stability of coronary artery disease on endothelial function parameters, C-reactive protein and homocysteine levels. Fifty-eight patients with angiographically documented coronary artery disease and 25 patients with normal coronary arteries were evaluated for risk factors, plasma homocysteine, C-reactive protein, and soluble adhesion molecule levels. Vascular cell adhesion molecule-1 and sE-selectin were significantly higher in the group with coronary artery disease than in healthy subjects (p = 0.005 and p = 0.031, respectively). Patients with unstable angina had significantly higher C-reactive protein (p < 0.001), troponin I (p < 0.01), and leukocyte counts (p < 0.05) than those with stable angina. sE-selectin levels were correlated with the extent of coronary atherosclerosis (r = 0.444, p < 0.05), and plasma homocysteine levels were associated with vascular cell adhesion molecule-1 (r = 0.479, p < 0.05) in unstable cases. These results suggest that vascular cell adhesion molecule-1 and sE-selectin are useful for determining the presence of coronary atherosclerosis, whereas C-reactive protein, troponin 1, and leukocyte count are predictors of clinical stability.

Going from immutable to mutable atherosclerotic plaques

Atherosclerotic coronary disease develops over several decades and was once thought to be an inevitable, irreversible consequence of aging. Atherogenesis is an inflammatory response that occurs after injury to the endothelium. Thrombosis, because of either endothelial erosion or plaque disruption, precipitates acute coronary events. Effective lipid lowering with statins has consistently and significantly decreased the risk that acute ischemic events will occur. The beneficial effects of statins likely result not only from their lipid-lowering effects but also from mechanisms that influence plaque behavior. Atherosclerotic plaques are not immutable; rather, their structure and composition can be altered by therapeutic modification. Ample evidence from clinical trials supports statin treatment in patients with stable coronary disease. Results of recent clinical trials support early treatment of high-risk patients with unstable coronary disease; early and aggressive statin treatment resulted in fewer recurrent ischemic events in patients with an acute coronary syndrome. Additional studies are needed to confirm the benefit of early statin treatment in patients with unstable coronary disease and to elucidate the reasons for the occurrence of events in treated patients. Research is also necessary to clarify the role of other lipids, as well as nonlipid risk factors, in the occurrence of acute ischemic events.

Chemokines in patients with ischaemic heart disease and the effect of coronary angioplasty

Percutaneous coronary transluminal angioplasty (PTCA) may release inflammatory mediators such as chemokines. Monocyte chemoattractant protein-1 (MCP-1) and eotaxin (EOX) are monocyte- and eosinophil-specific chemokines involved in the inflammation and pathogenesis of coronary atherosclerosis. A total of 28 patients undergoing elective PTCA, 20 coronary artery disease (CAD) patients undergoing coronary angiography and 28 healthy controls were studied. In PTCA patients before the procedure, MCP-1 plasma levels (441+/-64 pg/ml) were similar to those of CAD patients (430+/-24 pg/ml), and significantly higher compared with controls (145+/-17 pg/ml, P<0.01). MCP-1 rose significantly after 3 and 6 months following PTCA (696+/-89 and 876+/-86 pg/ml, respectively, P<0.01 vs. before PTCA). EOX plasma levels (155+/-14 pg/ml) were similar to those of CAD patients (157+/-14 pg/ml), but significantly higher compared with controls (83.2+/-10 pg/ml, P<0.05). EOX rose significantly 24 h (273+/-41 pg/ml, P<0.05) but not 3 months after PTCA (160+/-20 and 158+/-19 pg/ml, respectively). These findings indicate that chemokine-induced monocyte- and eosinophil-specific chemoattraction is stimulated in patients with coronary artery disease. MCP-1 levels remain significantly elevated for at least 6 months following elective PTCA, suggesting an inflammatory stimulation.

Risk stratification in non-ST segment elevation acute coronary syndromes with special focus on recent guidelines

Patients with unstable angina or non-ST segment elevation (non-Q-wave) myocardial infarction are a heterogeneous group with respect to their risk of developing clinically significant adverse events such as subsequent myocardial infarction and death. Recent guidelines promote risk stratification of these patients, targeting high-risk patients for maximal antithrombotic and antiischemic therapy and low-risk patients for early discharge. We reviewed current and future modalities for risk stratification of patients and the predictive value of these methods in context with available pharmacologic agents. Unfortunately, most of the data identifying a particular pharmacologic regimen as beneficial in high-risk patients are retrospectively derived from large trials. Until prospective studies that use markers to guide therapy are available, clinicians should be familiar with the use of these risk markers and their application to the role of a given management strategy, including pharmacologic therapy.

The inflamed plaque: cytokine production and cellular cholesterol balance in the vessel wall

Although the concept that inflammation plays a role in the biology of atherosclerosis is now well accepted, the basic feature of the arterial lesion remains the accumulation of clusters of foam cells. These clusters are the consequence of the enhanced recruitment of monocytes in the vessel wall induced by the hyperlipidemia and of the disproportionate accumulation of lipids in the cytoplasm of macrophages deriving from monocytes. Ultimately, every molecular force and pathway with modulating activity over the developing lesion will have to act on a convergence point with factors regulating cholesterol balance in the macrophage. Consistent with this view is the recent report that cytokines, such as tumor necrosis factor-alpha, can influence the expression of the scavenger receptor, whereas interferon-gamma can inhibit adenosine triphosphate-binding cassette transporter-1, the main effector of cholesterol efflux in the peripheral cell. Conversely, recent data have shown that primary alterations in macrophage cholesterol balance, such as those produced by the total absence of acylcoenzyme A:cholesterol acyltransferase-1, may determine local changes compatible with the activation of inflammatory pathways. In this brief review, we discuss some of the convergence points between inflammation and cholesterol balance, and we highlight the additional therapeutic targets suggested by these new developments in vascular biology.

Pravastatin reduces myocardial lesions induced by acute inhibition of nitric oxide biosynthesis in normocholesterolemic rats

Pravastatin is useful in restoring endothelium-dependent relaxation in hypercholesterolemic animals. A single intravenous bolus injection of N(omega)-nitro-L-arginine methyl ester (L-NAME), a non-specific inhibitor of NO synthase, causes myocardial necrosis and reduces coronary flow in rats. Since rats do not develop hypercholesterolemia and atherosclerosis, we have tested the hypothesis that pravastatin protects the heart from myocardial lesions induced by L-NAME in the absence of alterations in cholesterol levels and plaque formation. Male Wistar rats fed standard chow were divided into four groups: CONTROL (n=14) - rats that received tap water alone for 18 days; L-NAME (n=14) -- rats that received L-NAME (15 mg/kg, i.v.) on the 14th day of the study; PRAVASTATIN (n=11) -- rats that received pravastatin (6 mg/kg/day) in their drinking water for 18 days; PRAVASTATIN+L-NAME (n=12) -- rats that received pravastatin (6 mg/kg/day) and L-NAME (15 mg/kg, i.v.) as indicated in the preceding groups. At the end of 18 days, the rats were sacrificed and the hearts removed for stereological analysis by light microscopy. Plasma nitrate/nitrite and thromboxane B(2) concentrations were determined immediately before and after L-NAME administration. Pravastatin prevented the ischemic lesions induced by the acute inhibition of NO biosynthesis (the area of myocardial lesions in the L-NAME group was greater than in the Pravastatin+L-NAME group: 101.6 microm(2) vs. 1.2 microm(2), respectively; P<0.0001) and markedly increased the plasma nitrate/nitrate concentrations, even before L-NAME administration. There were no significant changes in the plasma thromboxane B(2) concentrations.