Myocardial injury: the acute phase response and lipoprotein metabolism

Usefulness of lipoprotein changes during acute coronary syndromes for predicting postdischarge lipoprotein levels

The aim of our study was to evaluate the lipoprotein changes that occur during acute coronary events, and to determine the lipoprotein threshold levels that identify patients who require future statin therapy. Lipoprotein levels were measured at admission, at 6 hours, the morning after admission, before discharge, and 3 months after discharge in patients with myocardial infarction and unstable angina. Patients with myocardial infarction on thrombolytic therapy (n = 63) and patients with unstable angina (n = 33) had a decrease in low-density lipoprotein (LDL) cholesterol levels < or = 24 hours after admission (-12 +/- 20% and -6 +/- 23%, respectively), but these levels returned to baseline before discharge. In patients with myocardial infarction who did not receive thrombolytic therapy (n = 37), the decrease was more gradual and peaked before hospital discharge (-7 +/- 19%). There was good correlation between LDL cholesterol levels at admission and after discharge, especially in normotriglyceridemic patients. Over 90% of patients with LDL cholesterol > or = 125 mg/dl on the morning after admission were candidates for statin therapy after discharge. Thus, the need for future statin therapy can be predicted with fair reliability during the initial 24 hours after admission. However, elevated baseline triglyceride levels significantly affect these LDL cholesterol changes and complicate prediction of long-term lipoprotein levels.

Variability in fibrinogen measurements: an obstacle to cardiovascular risk stratification

The clinical utility of fibrinogen measurement has been limited by large intraindividual variability. Several approaches that have been shown to improve the repeatability of fibrinogen include acquisition of samples at the same time of day, standardized sample procurement techniques, and multiple replicate sampling. This study employed established pre-analytical and analytical techniques known to reduce fibrinogen variability, including the acquisition of three replicate samples, each analyzed in duplicate, to evaluate the impact of intraindividual variability in fibrinogen measurement at baseline and 3 months on cardiovascular risk in 60 healthy subjects. Classification accuracy was evaluated by the ability to categorize subjects into tertiles of fibrinogen. Only 55% (33/60) of the subjects were correctly assigned to the appropriate fibrinogen tertile. Fibrinogen measurements varied by more than 10% in 45% of subjects and by 5% in 80% of subjects. Intraindividual variability in fibrinogen measurement with a functional assay limits cardiovascular risk assessment even when three replicates are averaged.

Effect of acute myocardial infarction on cholesterol ratios

OBJECTIVE

In patients with acute myocardial infarctions (MIs), cholesterol levels are no longer valid after 24 h from presentation because acute MI causes a rapid decline in serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. The objective of this study was to evaluate the effect of acute MI on the total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio.

METHODS

The study consisted of 45 patients who were admitted to the hospital with acute MIs. Serum levels of total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were determined on day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio were calculated. Serum lipid levels and cholesterol ratios were compared between day 1 post-MI and day 4 post-MI.

RESULTS

From day 1 post-MI to day 4 post-MI, the mean (+/- SD) serum levels of total cholesterol (188.4 +/- 52.5 vs. 170.5 +/- 57.2 mg/dL, respectively; p = 0.01), LDL cholesterol (120.3 +/- 48.9 vs. 105.9 +/- 43.0 mg/dL, respectively; p = 0.009), and HDL cholesterol (45.0 +/- 18.5 vs 39.3 +/- 16.1 mg/dL, respectively; p < 0.001) decreased, but the mean serum level of triglycerides (119.2 +/- 81.2 vs 149.3 +/- 68.3 mg/dL, respectively; p = 0.006) increased. The cholesterol ratios, however, remained unchanged between day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio was 4.59 +/- 1.84 on day 1 post-MI and 4.67 +/- 1.77 on day 4 post-MI (change not significant). The LDL cholesterol/HDL cholesterol ratio was 2.96 +/- 1.58 on day 1 post-MI and 2.99 +/- 1.44 on day 4 post-MI (change not significant).

CONCLUSION

Acute MI does not affect the cholesterol ratios. Therefore, when the absolute levels of serum cholesterol are no longer valid (beyond 24 h after an MI), the cholesterol ratios still could be useful for cholesterol risk assessment in patients with acute MIs.

Potential influence of timing of low-density lipoprotein cholesterol evaluation in patients with acute coronary syndrome

OBJECTIVE

To determine the significance of timing of low-density lipoprotein (LDL) cholesterol evaluation in patients with chest pain as it relates to subsequent National Cholesterol Education Program (NCEP) treatment decisions.

DESIGN

Prospective, observational study.

SETTING

A university-affiliated tertiary care hospital.

PATIENTS

Sixty-two patients with coronary heart disease who were not receiving lipid-lowering therapy and whose LDL levels were obtained 25-48 hours after onset of chest pain.

INTERVENTION

We evaluated laboratory test results of patients with chest pain admitted to the cardiac care unit to determine risk to patients when LDL levels obtained inappropriately are used to make decisions regarding antihyperlipidemic therapy.

MEASUREMENTS AND MAIN RESULTS

Inpatient and outpatient LDL levels were compared, and changes in NCEP treatment decisions analyzed. Differences between inpatient and outpatient LDL levels were significant (p<0.05), which frequently resulted in changes in therapy using the NCEP guidelines. The LDL levels of most inpatients were consistent with NCEP goals for patients with coronary heart disease, whereas the outpatient levels showed a need for drug therapy.

CONCLUSION

Lipid values obtained 25-48 hours after hospital admission in patients with acute coronary syndromes do not represent baseline values and may significantly alter the treatment approach; thus, they should not be used to direct drug therapy.

Elevated blood viscosity in systemic lupus erythematosus

OBJECTIVES

It has been proposed that elevated blood viscosity contributes to atherothrombotic and thromboembolic processes. We evaluated whether there is increased blood viscosity in systemic lupus erythematosus (SLE) that might contribute to cardiovascular complications and reduced tissue perfusion.

METHODS

Blood viscosity profiles were evaluated in SLE patients to determine whether rheologic disturbances contribute to the cardiovascular risk profile. Blood viscosity profiles were evaluated in 27 patients with SLE and 46 age- and gender-matched controls. Blood viscosity was measured at 37 degrees C and shear rates of 1 s(-1) and 100 s(-1), then corrected to the average hematocrit of the SLE patients.

RESULTS

Corrected blood viscosity values were higher in SLE patients than in controls at 100 s(-1) (P =.002). Positive correlations were found between the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index for SLE, which quantifies damage to 12 organ systems and fibrinogen (rho =.39; P =.042) and plasma viscosity (rho =.38; P =.049).

CONCLUSIONS

Our data indicate that blood viscosity values at a standard hematocrit are elevated in SLE patients. Further investigations are needed to evaluate whether the increased blood viscosity values in SLE patients contribute to cardiovascular complications and tissue ischemia.

CLINICAL RELEVANCE

Because blood viscosity values correlate with the clinical severity of SLE, blood viscosity may contribute to the cardiovascular complications and reduced tissue perfusion in SLE patients. Semin Arthritis Rheum 31:52-57.

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.

Measurement of plasma lipids in patients admitted with acute myocardial infarction or unstable angina pectoris

We assessed the reliability of early (first day) plasma lipid measurements in patients admitted with acute myocardial infarction or unstable angina pectoris. In 55 such patients, plasma levels of cholesterol and triglycerides measured within the first 24 hours after admission were significantly lower than the corresponding values at 6 weeks, which means that even very early in-hospital lipid measurements could lead to potentially serious underestimation of the lipid risk in these patients ad defined by the current criteria.

Effect of smoking on lipid profile, lipid peroxidation and antioxidant status in normal subjects and in patients during and after acute myocardial infarction

We studied changes in lipid peroxidation, vitamin E status and lipid profile due to smoking in healthy subjects, patients with acute myocardial infarction (MI), and in stabilized patients surviving MI. A significant increase in malondialdehyde (MDA) concentrations was observed in MI patients, more than in smokers (P<0.05), as compared to control. The plasma vitamin E as well as the ratio of vitamin E/lipids were significantly lower in MI patients as compared to stable ischemic heart disease (IHD) patients and controls. Our data show that smoking is associated with lowered antioxidant status in MI.

Interleukin-6 stimulates LDL receptor gene expression via activation of sterol-responsive and Sp1 binding elements

Inflammatory or malignant diseases are associated with elevated levels of cytokines and abnormal low density lipoprotein (LDL) cholesterol metabolism. In the acute-phase response to myocardial injury or other trauma or surgery, total and LDL cholesterol levels are markedly decreased. We investigated the effects of the proinflammatory cytokine interleukin (IL)-6 on LDL receptor (LDL-R) function and gene expression in HepG2 cells. IL-6 dose-dependently increased the binding, internalization, and degradation of (125)I-LDL. IL-6-stimulated HepG2 cells revealed increased steady-state levels of LDL-R mRNA. In HepG2 cells transiently transfected with reporter gene constructs harboring the sequence of the LDL-R promoter extending from nucleotide -1563 (or from nucleotide -234) through -58 relative to the translation start site, IL-6 dose-dependently increased promoter activity. In the presence of LDL, a similar relative stimulatory effect of IL-6 was observed. Studies using a reporter plasmid with a functionally disrupted sterol-responsive element (SRE)-1 revealed a reduced stimulatory response to IL-6. In gel-shift assays, nuclear extracts of IL-6-treated HepG2 cells showed an induced binding of SRE binding protein (SREBP)-1a and SRE binding protein(SREBP)-2 to the SRE-1 that was independent of the cellular sterol content and an induced binding of Sp1 and Sp3 to repeat 3 of the LDL-R promoter. Our data indicate that IL-6 induces stimulation of the LDL-R gene, resulting in enhanced gene transcription and LDL-R activity. This effect is sterol independent and involves, on the molecular level, activation of nuclear factors binding to SRE-1 and the Sp1 binding site in repeat 2 and repeat 3 of the LDL-R promoter, respectively.

Modest effects of exercise training alone on coronary risk factors and body composition in coronary patients

BACKGROUND

Cardiac rehabilitation programs have evolved to become secondary prevention centers. However, the independent effect of exercise alone on coronary risk factors and body composition in patients with coronary artery disease has not been well studied.

OBJECTIVE

The aim of this study was to determine the effect of exercise training alone, without modification of dietary intake, on coronary risk factors and body composition in a coronary population.

METHODS

The authors studied 82 coronary patients (23 females and 59 males) aged 61.2 +/- 12.2 years (mean +/- SD) before and after a 3-month exercise training program. Outcome variables included serum lipid values, glucose, insulin, body composition, body fat distribution, macronutrient intake, and peak aerobic capacity.

RESULTS

Neither male nor female patients experienced a significant overall improvement in plasma cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, glucose, or insulin levels after the 3-month exercise training program. Dietary macronutrient intake was unaltered during the study period. Peak aerobic capacity increased by 3.4 +/- 4.7 ml/kg/min (17%, P < 0.0001) and high-density lipoprotein (HDL)-cholesterol increased from 38 +/- 10 to 41 +/- 11 mg/dL (8%, P < 0.001) after the rehabilitation program. Patients with baseline triglyceride levels over 200 mg/dL experienced a 22% decrease (from 374 +/- 205 to 293 +/- 190 mg/dL; P < 0.05) after conditioning. Patients with baseline HDL-cholesterol levels under 35 mg/dL also improved overall by 17% (from 29 +/- 3 to 34 +/- 5 mg/dL; P < 0.0001). Exercise-induced changes in plasma HDL-cholesterol were more related to changes in body composition and/or body fat distribution, rather than changes in peak aerobic capacity.

CONCLUSION

Exercise conditioning alone resulted in relatively modest risk factor improvements in coronary patients after 3 months. High-density lipoprotein cholesterol measures increased by 3 +/- 8 mg/dL (8%). Patients with baseline triglyceride elevations experienced a 22% decrease. On the other hand, there were no overall effects on body weight, total cholesterol, LDL-cholesterol, triglycerides, glucose, or insulin levels. For most patients, exercise effects were minimal and nutritional and medical therapy will need to be used more aggressively to attain nationally recognized risk factor goals.

Plasma lipoprotein particle concentrations in postmenopausal women with unstable coronary artery disease. Analysis of diagnostic accuracy using receiver operating characteristics

BACKGROUND

The contribution of plasma lipids to cardiovascular risk is usually evaluated by measuring plasma concentrations of total cholesterol, triglycerides and HDL cholesterol, and calculating LDL cholesterol concentration. We investigated plasma concentrations of apolipoproteins and lipoprotein particles in women with unstable coronary artery disease (CAD) to evaluate whether these, better than the routine lipid status, could differentiate women with and without coronary atherosclerosis.

METHODS

Blood samples for lipid analyses were collected from 119 angiographically examined postmenopausal 49-79-year-old women with unstable CAD, and from 101 age-matched controls. Mean plasma concentrations were compared and the discriminatory ability of the different variables were tested using receiver operating characteristics (ROC).

RESULTS

At coronary angiography 19% had normal vessels and 81% had coronary atherosclerosis. A disturbed triglyceride metabolism was the most pronounced lipid abnormality in women with unstable CAD and coronary atherosclerosis. ROC showed that none of the evaluated variables had a particularly high discriminatory power regarding unstable CAD or coronary atherosclerosis. The ratio cholesterol/HDL cholesterol was best with an ROC area of 0.79. Furthermore, the newer lipid variables, i.e. lipoprotein particles and apolipoproteins, were no better than the traditional variables.

CONCLUSION

Lipoprotein changes reflecting a disturbed triglyceride metabolism are most pronounced in women with unstable CAD and coronary atherosclerosis. Lipoprotein particles and apolipoproteins alone were no better than lipids and lipoproteins in separating women with from those without coronary atherosclerosis. Our study does not support the measurement of apolipoproteins and lipoprotein particles on the basis of diagnostic accuracy alone.

Whole blood folate, homocysteine in serum, and risk of first acute myocardial infarction

High level of total homocysteine (tHcy) is a risk factor for coronary artery disease (CAD), but the mechanism is not known. The serum concentration of tHcy, total cholesterol, high density lipoprotein cholesterol (HDL-C), and apolipoprotein A-I (apo A-I) and the concentration of folate in whole blood were measured in 107 patients with first acute myocardial infarction (MI) and 103 controls. The level of whole blood folate was lower and that of tHcy higher in cases than in controls. An increase of 50 nmol/l whole blood folate was associated with an OR for MI of 0.75, and an increase of 5 micromol/l tHcy with an OR for MI of 1.57. Correlations were observed between the levels of whole blood folate and tHcy and between whole blood folate and alcohol intake, and in MI cases, between tHcy, HDL-C, and apo A-I as well as between HDL-C and alcohol intake. The number of cigarette smokers was higher among cases than controls. In smokers, the level of tHcy was higher and that of whole blood folate lower than in non-smokers. After adjustment for smoking, the whole blood folate and tHcy-associated risks of MI became non-significant. We conclude that smoking may affect folate status and tHcy level adversely. The risk of MI in smokers may at least partly be attributed to hyperhomocysteinemia or low folate.

Increased systemic oxidative stress after elective endarterectomy: relation to vascular healing and remodeling

It has been reported that systemic and local redox state may have an important role in the functional and organic changes characterizing the process of vascular response to injury. Carotid endarterectomy to remove atherosclerotic plaque is followed by a long lasting healing and remodeling process that can be carefully followed over time with noninvasive ultrasonography. Plasma vitamin C concentration and native LDL (n-LDL) content in lipid peroxides, vitamin E, beta-carotene, and lycopene as well as LDL susceptibility to peroxidation were assessed in 45 patients undergoing elective endarterectomy for internal carotid stenosis, at baseline, 24 hours, 3 and 15 days, and 1 month after surgery. Serial duplex scans were performed in all patients postoperatively and 3, 6, and 12 months. The changes in far wall thickness (FW) and % renarrowing from postoperatively to 12 months were used as remodeling indices. Plasma antioxidant vitamins and lag-phase showed a sharp and significant decrease during the first 24-hours after surgery remaining unchanged until the third day, whereas, an opposite trend was evidenced for n-LDL content in lipid peroxides and serum ceruloplasmin. After the third day all the parameters returned progressively to baseline within one month from endarterectomy. Interestingly, the n-LDL lipid peroxide content, the serum ceruloplasmin and the plasma vitamin C concentration, measured at 24 and 3 days from surgery, were significantly associated to the change in % renarrowing from postoperatively to 12 months. The higher the LDL content in lipid peroxides, the higher the serum level of ceruloplasmin, the lower the plasma content in vitamin C and the higher the % of vessel renarrowing. In conclusion, carotid endarterectomy with atherosclerotic plaque removal is associated with an acute and prolonged increase in systemic oxidative stress that influences vascular healing and late luminal loss.

Serum amyloid A, the major vertebrate acute-phase reactant

The serum amyloid A (SAA) family comprises a number of differentially expressed apolipoproteins, acute-phase SAAs (A-SAAs) and constitutive SAAs (C-SAAs). A-SAAs are major acute-phase reactants, the in vivo concentrations of which increase by as much as 1000-fold during inflammation. A-SAA mRNAs or proteins have been identified in all vertebrates investigated to date and are highly conserved. In contrast, C-SAAs are induced minimally, if at all, during the acute-phase response and have only been found in human and mouse. Although the liver is the primary site of synthesis of both A-SAA and C-SAA, extrahepatic production has been reported for most family members in most of the mammalian species studied. In vitro, the dramatic induction of A-SAA mRNA in response to pro-inflammatory stimuli is due largely to the synergistic effects of cytokine signaling pathways, principally those of the interleukin-1 and interleukin-6 type cytokines. This induction can be enhanced by glucocorticoids. Studies of the A-SAA promoters in several mammalian species have identified a range of transcription factors that are variously involved in defining both cytokine responsiveness and cell specificity. These include NF-kappaB, C/EBP, YY1, AP-2, SAF and Sp1. A-SAA is also post-transcriptionally regulated. Although the precise role of A-SAA in host defense during inflammation has not been defined, many potential clinically important functions have been proposed for individual SAA family members. These include involvement in lipid metabolism/transport, induction of extracellular-matrix-degrading enzymes, and chemotactic recruitment of inflammatory cells to sites of inflammation. A-SAA is potentially involved in the pathogenesis of several chronic inflammatory diseases: it is the precursor of the amyloid A protein deposited in amyloid A amyloidosis, and it has also been implicated in the pathogenesis of atheroscelerosis and rheumatoid arthritis.

Low high density lipoprotein levels are associated with an elevated blood viscosity

Low levels of high density lipoprotein (HDL) have been inversely correlated with blood viscosity and plasma viscosity; however, the contribution of concomitant hypertriglyceridemia may confound this association. This study evaluated the relationship between blood viscosity and HDL cholesterol in 70 subjects with fasting levels of total cholesterol <5.2 mmol/l (200 mg/dl) and triglycerides <2.3 mmol/l (200 mg/dl). Viscosity (mPa x s) was measured at 37 degrees C with a coaxial cylinder microviscometer. HDL cholesterol was inversely associated with corrected blood viscosity at 100 s(-1) (beta = -0.49, P<0.00005) and 20 s(-1) (beta = -0.38, P = 0.001) but not at 1 s(-1) (beta = -0.05, P = 0.69) using stepwise multivariate analyses. Low HDL levels are associated with an elevated blood viscosity, and this rheological abnormality may contribute to cardiovascular risk in subjects with isolated low HDL levels.

Lipid lowering in the cardiac rehabilitation setting

PURPOSE

The authors determined the frequency and effectiveness of pharmacologic lipid lowering, guided by the recommendations of the National Cholesterol Education Program (NCEP) before and after institution of a systematic lipid assessment performed at the time of the cardiac rehabilitation entry evaluation.

METHODS

The systematic lipid evaluation included a full lipid profile and a dietary evaluation at which time an active approach to pharmacologic lipid therapy was taken. Therapy was guided by the NCEP guidelines, with the collaboration of the referring physician. The frequency of lipid therapy change (starting or changing therapy) from the baseline evaluation to a 3-month follow-up visit was the primary study outcome variable. The control group consisted of 51 patients with coronary heart disease (CHD) seen in 1995 at cardiac rehabilitation, who agreed to have their serum lipids measured in a double-blinded fashion. There was no systematic lipid lowering intervention. The intervention group consisted of 187 patients with CHD who participated in cardiac rehabilitation in 1996 to 1997.

RESULTS

At baseline, a similar percentage of patients in each group were on lipid lowering therapy: 38% (19/51) in controls versus 35% (65/187) in intervention patients. Among patients with a baseline low-density lipoprotein (LDL) cholesterol of > or = 130 mg/dL, therapy was modified in 18% (4/22) of control patients compared with 52% (35/68) of intervention patients (P < 0.05). Among patients with a baseline LDL cholesterol of > or = 160, therapy was altered in 22% (2/9) control patients compared with 72% (18/25) intervention patients (P < 0.01). In both risk strata of > or = 130 mg/dL and > or = 160 mg/dL, LDL cholesterol measures were lowered to a greater degree in the intervention group.

CONCLUSIONS

The performance of a systematic lipid review at the time of cardiac rehabilitation entry, with an active stance toward pharmacologic therapy, results in a threefold increase in pharmacologic modifications and lower LDL cholesterol values for cardiac rehabilitation participants.

Serum amyloid A (SAA): a concise review of biology, assay methods and clinical usefulness

Serum amyloid A (SAA) is a family of proteins encoded in a multigene complex. Acute phase isotypes SAA1 and SAA2 are synthesized in response to inflammatory cytokines. SAA and C-reactive protein (CRP) are now the most sensitive indicators for assessing inflammatory activity. In viral infection and kidney allograft rejection, SAA proved more useful than CRP. Development of convenient assay methods for SAA will facilitate its use in clinical laboratories.

Upregulation of cholesterol synthesis after acute myocardial infarction--is cholesterol a positive acute phase reactant?

Acute myocardial infarction is associated with profound alterations in the plasma lipoprotein profile. The mechanism of these alterations is not clear, and both cholesterol biosynthesis up- and downregulation could possibly be a consequence of acute myocardial infarction. We determined plasma lipids, lipoproteins, apolipoproteins, and lathosterol-which is regarded as an estimate of whole body cholesterol biosynthesis in humans-concentrations in 34 patients (age 68+/-10 years, 24 male, 10 female) admitted to our hospital with acute MI and with onset of symptoms within the last 12 h. Samples were taken immediately after admission to the hospital, and 1, 2, and 10 days after admission. On the first day after admission there was a decrease in total cholesterol (C) by 14.1%, (P = 0.01), in LDL-C by 14.4% (P = 0.03), in HDL-C by 9.3% (NS), and in triglycerides by 19.5% (NS). Apolipoprotein B100 was reduced by 18.3% (P = 0.008), and apolipoprotein AI by 12.3% (NS). The lathosterol/cholesterol ratio was increased by 23.1% after 1 day, and by 28.7% after 2 days (P = 0.05). After 10 days, all variables except the apolipoproteins had essentially returned to baseline values. In conclusion, the changes in the plasma lipid profile after acute myocardial infarction are associated with a profound increase of whole body cholesterol biosynthesis as judged by the lathosterol/cholesterol ratio. These changes may possibly enhance the delivery of cholesterol to cells involved in tissue repair mechanisms after acute myocardial infarction.

Inflammation enhances cardiovascular risk and mortality in hemodialysis patients

BACKGROUND

Atherosclerosis, a major problem in patients on chronic hemodialysis, has been characterized as an inflammatory disease. C-reactive protein (CRP), the prototypical acute phase protein in humans, is a predictor of cardiovascular mortality in the general population. We hypothesize that several of the classic, as well as nontraditional, cardiovascular risk factors may respond to acute phase reactions. An activated acute phase response may influence or predict cardiovascular risk.

METHODS

In 280 stable hemodialysis patients, serum lipids, apolipoproteins (apo) A-I and B, lipoprotein(a) [Lp(a)], fibrinogen, and serum albumin (Salb) were determined in relation to CRP and serum amyloid A (SAA), two sensitive markers of an acute phase response. Mortality was monitored prospectively over a two year period.

RESULTS

Serum CRP and SAA were found to be elevated (more than 8 and more than 10 mg/liter, respectively) in 46% and 47% of the patients in the absence of clinically apparent infection. Patients with elevated CRP or SAA had significantly higher serum levels of Lp(a), higher plasma fibrinogen, and lower serum levels of high-density lipoprotein cholesterol, apo A-I, and Salb than patients with normal CRP or SAA. The rise in Lp(a) concentration was restricted to patients exhibiting high molecular weight apo(a) isoforms. During follow-up, 72 patients (25.7%) had died, mostly due to cardiovascular events (58%). Overall mortality and cardiovascular mortality were significantly higher in patients with elevated CRP (31% vs. 16%, P < 0.0001, and 23% vs. 5%, P < 0.0001, respectively) or SAA (29% vs. 19%, P = 0.004, and 20 vs. 10%, P = 0.008, respectively) and were also higher in patients with Salb of lower than 40 g/liter (44% vs. 14%, P < 0.0001, and 34% vs. 6%, P < 0.0001, respectively). Univariate Cox regression analysis demonstrated that age, diabetes, pre-existing cardiovascular disease, body mass index, CRP, SAA, Salb, fibrinogen, apo A-I, and Lp(a) were significantly associated with the risk of all-cause and cardiovascular mortality. During multivariate regression analysis, SAA, fibrinogen, apo A-I, and Lp(a) lost their predictive values, but age and CRP remained powerful independent predictors of both overall death and cardiovascular death.

CONCLUSION

These results suggest that a considerable number of hemodialysis patients exhibit an activated acute phase response, which is closely related to high levels of atherogenic vascular risk factors and cardiovascular death. The mechanisms of activated acute phase reaction in patients on chronic hemodialysis remain to be identified. A successful treatment of the inflammatory condition may improve long-term survival in these patients.

Angiotensin-converting enzyme inhibition as antiatherosclerotic therapy: no answer yet. QUIET Investigators. QUinapril Ischemic Event Trial

Angiotensin-converting enzyme inhibitors have proven to be of clinical benefit in congestive heart failure. Whether they also provide benefit to patients with coronary artery disease in the absence of congestive heart failure via an antiatherosclerotic mechanism is a question the QUinapril Ischemic Event Trial quantitative coronary angiography (QCA) study attempted to answer: 1,750 patients with normal left ventricular function who were undergoing coronary angiography and angioplasty were randomized to 20 mg/day of quinapril versus placebo and followed for 3 years for cardiac end points. A randomly selected subgroup of the total cohort underwent follow-up angiography. The primary QCA end point was the categorical designation of progression versus nonprogression, defined either by QCA or by a cardiac event in patients selected for the QCA trial who had no usable follow-up x-ray film. Secondary end points in patients with 2 angiograms were: new stenosis development, change in minimum lumen diameter index, and change in percent diameter stenosis index. There were 119 progressors among 243 placebo-treated patients (49%) and 111 progressors among 234 quinapril-treated patients (47%) (p = NS). There were 44 patients with new stenosis development in the placebo group (19%) and 50 (22%) in the quinapril group (p = NS). Change in minimum lumen diameter index was -0.21+/-0.03 mm in the placebo group and -0.18+/-0.03 mm in the quinapril group (p = NS). Finally, change in percent diameter stenosis index was +5.1+/-1.0 in the placebo group and +3.5+/-1.0 in the quinapril group (p = NS). Potential confounders of this trial are presented and discussed.

Cardiovascular risk factors associated with clinically isolated and diffuse atherosclerosis in Spanish patients with coronary artery disease

BACKGROUND

Patients with coronary artery disease (CAD) associated with peripheral (PAD) or cerebrovascular disease (CVD), a condition called diffuse atherosclerosis, have a higher risk of death than patients with isolated CAD. The prevalence of diffuse atherosclerosis and the atherogenic risk factors associated with this condition in our geographic area have not been described previously.

METHODS

A cohort of 2597 patients (62 +/- 10.8 years, 665 women) consecutively admitted at Bellvitge Hospital because of acute coronary syndromes were studied. CAD patients were divided in two groups with diffuse and located atherosclerosis according to whether they had or they had not an associated PAD or CVD. Baseline history, physical data and lipid profile were recorded in each patient according to a standardized questionnaire.

RESULTS

A total of 370 patients (14.2%) had diffuse atherosclerosis. Among them, there were more men and women older than 55 years than among those with isolated CAD. Patients with diffuse atherosclerosis were more frequently hypertensive, diabetic and former smokers than those with isolated CAD (60.5% vs. 49.4%, P < 0.01; 37.4% vs. 24.5%, P < 0.01; and 47% vs. 35.7%, P < 0.01, respectively). There were no significant differences in the mean values of total cholesterol (TC), low-density cholesterol (LDL-C), high-density cholesterol (HDL-C) and triglycerides between both groups of patients, but patients with diffuse atherosclerosis had a lower HDL-C/TC ratio, with borderline statistical significance (0.18 +/- 0.06 vs. 0.19 +/- 0.06, P = 0.06). Using multiple logistic regression analysis, the variables associated with diffuse atherosclerosis in men were age greater than 55 years (OR 1.97, CI 1.33-2.93), hypertension (OR 1.50, CI 1.14-2.20), diabetes (OR 1.78, CI 1.20-2.70), smoking (former smokers) (OR 2.09, CI 1.36-3.24) and HDL-C/TC < 0.20 (OR 1.60, CI 1.18-2.17); and in women hypertension (OR 3.43, CI 1.48-7.94) and diabetes (OR 2.58, CI 1.55-4.80).

CONCLUSIONS

Clinically overt diffuse atherosclerosis is a relatively common disease. Older patients and those with hypertension, diabetes or low HDL-C/TC ratio are more likely to have diffuse atherosclerosis than those without these conditions.

Acute effects of a surgical menopause on serum concentrations of lipoprotein(a)

OBJECTIVE

The aim of this study was to investigate acute changes in serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins after a surgical menopause.

METHODS

A total of 100 premenopausal Chinese women who were booked for hysterectomy for benign gynecological disorders were recruited. They study group comprised 40 subjects undergoing hysterectomy as well as bilateral oophorectomy. The control group consisted of 60 subjects undergoing hysterectomy with conservation of the ovaries. Complete data were available from 30 of the 40 subjects in the study group and from 44 of the 60 controls. Serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins were measured before surgery and these measurements were repeated 3 days, 8 weeks and 6 months postoperatively. Those study patients who received hormone replacement therapy and control patients who became menopausal, according to biochemical criteria, during the study period were excluded from analysis.

RESULTS

Three days after surgery, there was a significant increase in the mean lipoprotein(a) concentration in the control group from 19.1 to 23.0 mg/dl (p < 0.01), but there was no significant change in the study group. There were no significant changes from baseline in the mean lipoprotein(a) concentration in either group 8 weeks or 6 months after surgery. There was a significant increase in the mean concentration of total cholesterol in the study group 8 weeks after surgery from 5.08 to 5.45 mmol/l (p < 0.01), in low density lipoprotein cholesterol from 3.22 to 3.49 mmol/l (p < 0.01), and in apolipoprotein B from 95.6 to 103.0 mg/dl (p < 0.05). However, the mean concentrations 6 months after surgery were not significantly different from baseline levels. The mean concentrations of high density lipoprotein cholesterol, apolipoprotein A-1 and triglycerides also did not differ significantly from baseline in the study group, either 8 weeks or 6 months after surgery.

CONCLUSIONS

These results suggest that any increase in concentrations of lipoprotein(a), and other atherogenic lipids and lipoproteins which occur after the menopause, develops relatively slowly. The changes in concentrations which occurred within 8 weeks of surgery were probably an acute-phase reaction after surgery rather than a response to a decreasing estradiol concentration.

Dyslipidemias have a detrimental effect on left ventricular systolic function in patients with a first acute myocardial infarction

Several large-scale clinical trials have shown that lipid-lowering interventions are associated with reduced coronary events and mortality. However, whether dyslipidemias have a detrimental effect on the evolution of myocardial infarction (MI) is still unknown. To examine whether dyslipidemias can aggravate myocardial vulnerability following MI, 165 patients with a first MI were studied. All patients underwent measurements of serum lipid profiles 1 week and 3 months after MI, a radionuclide ventriculographic study, and a coronary angiographic study. The patients were divided into 3 groups according to their 3-month serum cholesterol levels (group 1, <200 mg/dl; group 2, 200 to 240 mg/dl; group 3, >240 mg/dl). Groups 1, 2, and 3 consisted of 66, 59, and 40 patients, respectively. Group 3 had a higher Gensini score than groups 1 and 2, although this was not statistically significant (p = 0.13). The postinfarct left ventricular ejection fraction (LVEF) was highest in group 1 (53 +/- 13%), at mid level in group 2 (43 +/- 14%), and lowest in group 3 (35 +/- 11%) (p < 0.0001). A significant negative correlation between 3-month low-density lipoprotein (LDL) cholesterol (r = -0.55, p < 0.0001) and the postinfarct LVEF was found. The product of peak creatine kinase (CK(MAX)) and time to CK(MAX) (p = 0.001), and patency of the infarct-related artery (p = 0.009), rather than variables of coronary atherosclerosis, were also independent predictors of the postinfarct LVEF. Increases in 1-week LDL cholesterol and decreases in 1-week high-density lipoprotein cholesterol were associated with a higher CK(MAX) and a lower patency rate of the infarct-related artery, respectively. This study revealed that dyslipidemias per se, especially LDL cholesterol, had a detrimental effect on the postinfarct LVEF; this effect might be independent of the atherogenic properties of dyslipidemias.

Analysis of changes in acute-phase plasma proteins in an acute inflammatory response and in rheumatoid arthritis using two-dimensional gel electrophoresis

Two-dimensional (2-D) gel analysis was used to examine differences in the levels of 19 plasma proteins: before and after an acute inflammatory reaction (parenteral typhoid vaccination) in normal subjects, between rheumatoid arthritis (RA) patients and normals and in RA patients treated with tenidap (120 mg) and piroxicam (20 mg). Typhoid vaccination increased levels of SAA, haptoglobin alpha1, haptoglobin alpha2, haptoglobin beta and alpha1-anti-chymotrypsin but decreased transthyretin and apolipoprotein E. In RA patients, serum amyloid A (SAA), haptoglobin alpha2, haptoglobin beta, alpha1-antichymotrypsin and C3 proactivator levels were elevated while apolipoprotein A-I, apolipoprotein A-IV, transthyretin, Gc-globulin, alpha2-HS glycoprotein, alpha2-macroglobulin and alpha1-B glycoprotein levels were decreased, compared to normals. Compared to piroxicam, tenidap lowered levels of alpha1-antiprotease and SAA but raised the levels of transthyretin, Gc-globulin, alpha2-HS-glycoprotein and alpha2-macroglobulin in RA patients. C-reactive protein (CRP) could not be quantified on 2-D gels but, when measured by rate nephelometry, levels were reduced after treatment with tenidap compared to piroxicam. The general pattern of the acute phase protein response to an acute inflammatory response to typhoid vaccination is similar to that in the chronic inflammatory condition, RA. The impact of tenidap on both positive and negative acute-phase proteins in RA patients could clearly be distinguished from that of piroxicam.

Propofol 2% in critically ill patients: effect on lipids

OBJECTIVE

To investigate the concentrations of triglyceride, cholesterol, and high-density lipoprotein during a 50-hr infusion of 2% propofol, starting within 24 hrs of admission to the intensive care unit (ICU).

DESIGN

Prospective, clinical study.

SETTING

ICU, university hospital.

PATIENTS

Thirty adult patients, who were ventilated and expected to be sedated for >2 days, were studied for 50 hrs, beginning at 1800 hrs on the first day of ICU admission.

MEASUREMENTS AND MAIN RESULTS

Triglyceride, cholesterol, and high-density lipoprotein were measured at 2000, 0400, and 0800 hrs. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein were measured at 2000 hrs. Median cholesterol and high-density lipoprotein concentrations were at the low end of the normal range. In seven patients, peak triglyceride concentrations were >3 mmol/L up to a maximum of 4.83 mmol/L. Although there was no statistical difference in lipid concentrations between days 1 and 2, there was an apparent pattern of increasing triglyceride concentrations. There was a correlation between peak triglyceride concentration and total propofol consumption, but there was no correlation between lipids and age, gender, or Acute Physiology and Chronic Health Evaluation II scores. There was a direct correlation between triglyceride and C-reactive protein concentrations, and an inverse correlation between cholesterol and C-reactive protein. Twenty-two patients had evidence of TNF and 11 patients had an IL-6 of >1000 pg/mL, but there was no relationship between concentrations of cytokines and triglycerides in plasma.

CONCLUSIONS

Infusion of 2% propofol to critically ill patients over a 50-hr period does not result in a significant increase in triglyceride concentrations. Mean cholesterol and high-density lipoprotein concentrations were low throughout the study period. There was a significant direct correlation between triglyceride and C-reactive protein and an inverse correlation between cholesterol and C-reactive protein, suggesting that the changes in lipids in critically ill patients may be partly attributable to the acute-phase response.

Acute inflammation, acute phase serum amyloid A and cholesterol metabolism in the mouse

Acute inflammation results in a profound change in the apolipoprotein composition of high density lipoprotein (HDL). Several isoforms of the serum amyloid A (SAA) family, SAA1 and SAA2, become major components of HDL. This structural relationship has suggested that acute phase SAA plays some as yet unidentified role in HDL function, possibly related to cholesterol transport, during the course of acute inflammation. Using subcutaneous AgNO3 to induce a sterile abscess changes in plasma cholesterol and SAA were monitored over the subsequent 144 h. Total plasma cholesterol began to increase within 12 h of the induction of inflammation and reached a peak in 24 h. Thereafter its plasma levels fell returning to normal values by 96-120 h. The bulk of the increase in plasma cholesterol was found in the free cholesterol fraction of HDL. This pattern of cholesterol increase corresponds to the established temporal changes for acute phase SAA (AP-SAA). AP-SAA levels increased within 8 h of the induction of inflammation and reached a peak at 24 h. They began to decrease by 48 h with small quantites still present 120 h later. In concert, but inversely, with the changes in AP-SAA the apoA-I, apoA-II, and apo-E, content of HDL decreased during the AP-SAA increases and increased as AP-SAA levels fell. The plasma appearance of cholesterol from the periphery, and central parts of the inflammatory site was assessed by the use of radiolabelled cholesterol. The peripherally placed cholesterol rapidly reached a peak plasma concentration within 24 h of injection. Cholesterol placed in the central part of the sterile abscess, a site relatively inaccessible to the vasculature required 48 h to reach its peak and was 5-times lower than that placed peripherally. The influence of AP-SAA on neutral cholesterol ester hydrolase (nCEH) activity in mouse liver homogenates, mouse peritoneal macrophage homogenates, and a purified porcine pancreatic enzyme with nCEH activity was also assessed. Following optimization with regard to pH, bile salt concentration, protein concentration and incubation time, mouse peritoneal macrophages had a significantly higher nCEH specific activity than that found in liver (7-8 fold). Purified AP-SAA, assessed over a concentration range of 0-10 microg/ml, enhanced nCEH activity at concentrations above 2 microg/ml. The nCEH activity, regardless of its source, increased by 3-7 fold in the presence of AP-SAA. Equivalent concentrations of apolipoprotein A-I (apo A-I) and bovine serum albumin (BSA) failed to alter the activity of nCEH. The effect of AP-SAA on a purified form of nCEH suggests that AP-SAA may have a direct effect on the activity of this enzyme. The temporal correlation of circulating AP-SAA and plasma cholesterol and the significant stimulation of nCEH by AP-SAA (but not apoA-I or BSA) provides further evidence that AP-SAA plays a role in cholesterol metabolism during the course of acute inflammation.

Involvement of an SAF-like transcription factor in the activation of serum amyloid A gene in monocyte/macrophage cells by lipopolysaccharide

Serum amyloid A (SAA) has been linked to atherosclerosis because of its ability to remodel high-density lipoprotein by the depletion of apolipoprotein A1, its ability to bind cholesterol, and its presence in the atherosclerotic plaques of coronary and carotid arteries. In the present study, we investigated the induction mechanism of SAA gene in THP-1 monocyte/macrophage cells which play a critical role in the development of atherosclerotic fatty streak and plaque formation. We and others have shown that SAA gene is induced in monocyte/macrophage cells by lipopolysaccharide (LPS). By promoter function analysis, we show that the SAA promoter sequence between -280 and -226 can confer LPS responsiveness. Gel electrophoretic mobility shift assay detected an induced DNA-binding activity in these cells in response to LPS. Characterization of the DNA-binding protein by UV cross-linking, Southwestern blot, and antibody ablation/supershift assays revealed that it is similar to a recently reported nuclear factor designated SAF. These results demonstrated that LPS-mediated SAA gene induction in monocyte/macrophage cells is primarily due to the induction of SAF activity.

Dynamic changes of plasma lipids and lipoproteins in patients after transient ischemic attack or minor stroke

PURPOSE

Only few data are available concerning variations of lipids and lipoproteins in the acute stage after ischemic cerebrovascular events. It was the aim of this study to investigate whether the lipid and lipoprotein levels obtained in the first few days after a transient ischemic attack (TIA) or a minor stroke (MS) actually reflect "correct' values or "changed' (ie, false low) values, as in patients after acute myocardial infarction.

PATIENTS AND METHODS

Total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), and triglyceride (TG) levels of 37 unselected patients with TIA or MS were determined within 12-48 hours (Group A) or within 49-168 hours (Group B) after the acute event. After a mean observation period of 15.3 months, all patients were re-examined; the results were compared with those of the baseline evaluation.

RESULTS

At the time of the baseline evaluation, TC and LDL-C levels of Group B patients were significantly lower than Group A levels. At the end of the observation period, however, Group A and Group B patients did not differ with regard to all four parameters. In comparison with the baseline examination, the values of Group A patients had not changed. In Group B patients, however, TC, HDL-C, LDL-C, and TG levels had significantly increased.

CONCLUSION

Our results strongly suggest that lipid and lipoprotein levels of patients with TIA or MS should be assessed within a maximum of 48 hours after the acute event. If the examination cannot be performed within that period, the determination of reliable values is possible only after several weeks or months.

Direct measurement of serum low-density lipoprotein cholesterol in patients with acute myocardial infarction on admission to the emergency room

Measurement of low-density lipoprotein cholesterol during acute myocardial infarction in nonfasting patients on initial presentation to an emergency room by any of 3 methods (ultracentrifugation, immunoseparation, or the Friedewald estimate), identifies patients eligible for antilipemic interventions. Although slightly less sensitive, the conventional Friedewald estimate of low-density lipoprotein cholesterol levels provides clinicians good correlation with ultracentrifugation.

Serum lipids four weeks after acute myocardial infarction are a valid basis for lipid lowering intervention in patients receiving thrombolysis

OBJECTIVE

To compare serum concentrations of total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides four weeks after acute myocardial infarction with baseline levels measured within 24 hours after onset of symptoms.

DESIGN

A prospective study including 141 patients with acute myocardial infarction who were admitted to the coronary care unit at a general hospital.

MEASUREMENTS

Fasting serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

MAIN RESULTS

In patients receiving thrombolytic therapy, no significant differences were found in serum lipids four weeks after admission compared to values estimated within 24 hours from onset of symptoms. In patients not receiving thrombolytic therapy, total cholesterol and low density lipoprotein cholesterol showed a minor increase four weeks after admission compared to values obtained within 24 hours after onset of symptoms. High density lipoprotein cholesterol and triglycerides remained unchanged.

CONCLUSIONS

In patients with acute myocardial infarction receiving thrombolytic therapy, serum lipids measured four weeks after onset of infarction are reasonably valid estimates of baseline lipid levels and may be used to decide about lipid lowering interventions. This information can be a basis for actions against hyperlipidaemia early after hospital discharge when the patient is highly motivated to change lifestyles and is still in close contact with a cardiologist or other physician.

Dyslipidemias and the secondary prevention of coronary heart disease

Dyslipidemias in patients with coronary heart disease confer a greater risk of ischemic cardiac events than comparable dyslipidemias in people free of disease. A major dyslipidemia can be diagnosed in more than 80% of patients with established premature coronary heart disease. These dyslipidemias constitute not only elevations of low-density lipoprotein cholesterol (hypercholesterolemia) but also indicate abnormalities in the metabolism of triglyceride-rich lipoproteins, high-density lipoproteins, and lipoprotein(a). Clinical trials have demonstrated that therapy to lower low-density lipoprotein levels can delay angiographic progression of coronary stenoses and reduce recurrent cardiac event rates. These clinical benefits from low-density lipoprotein cholesterol lowering may occur as early as 6 to 12 months after initiation of therapy. Intervention strategies for dyslipidemias are directed toward lowering the low-density lipoprotein cholesterol fraction to 90 to 100 mg/dl. This approach begins with dietary modification, weight loss, smoking cessation, and aerobic exercise. Patients with hypercholesterolemia refractory to nonpharmacologic intervention require lipid-lowering agents. The choice of lipid-lowering medications is influenced by concomitant abnormalities of lipoprotein metabolism, such as hypertriglyceridemia or hypoalphalipoproteinemia. Treatment of primary dyslipidemias other than hypercholesterolemia may be warranted in the presence of other cardiac risk factors; however, a broader spectrum of clinical trial data is needed to support or refute this contention.