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

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

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

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

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

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

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

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

Surrogate endpoints and newer risk markers in atherosclerosis management

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

Case 4: type 2 diabetes, hypertension, and dyslipidemia

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

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

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

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

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

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

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

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

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