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John F Carlquist

Publications and source records attributed to John F Carlquist.

30 records · Page 2Linked to original sources
PubMed2004

Effect of folic acid fortification of food on homocysteine-related mortality.

PURPOSE: In 1998, the Food and Drug Administration mandated the fortification of food products with folic acid. The effect of this rule on mortality associated with homocysteine levels in patients with coronary artery disease is unknown. METHODS: We studied 2481 consecutive patients with coronary artery disease who underwent coronary angiography between 1994 and 1999, and who had baseline homocysteine measurements and at least 2 years of follow-up. Patients were divided into prefortification (1994 to 1997, n = 1595) and postfortification (1998 to 1999, n = 886) groups, as well as classified based on baseline homocysteine levels (normal to low, intermediate, and high). Homocysteine levels were measured by fluorescence polarization immunoassay. Mortality was determined by telephone survey or from a national Social Security database or hospital records. RESULTS: After implementation of the fortification rule, median homocysteine levels declined from 13.8 to 12.3 micromol/L (P <0.001), and the proportion of patients with high homocysteine levels (>15 micromol/L) decreased from 41% (n = 650) to 28% (n = 249) (P <0.001). Overall, homocysteine was a modest risk factor for mortality (adjusted relative risk [RR] = 1.03 per micromol/L; 95% confidence interval [CI]: 1.01 to 1.05; P = 0.006). There was no significant interaction between fortification status and homocysteine category with mortality (P for interaction = 0.85). Two-year mortality was reduced minimally (7.8% [n = 124] to 7.2% [n = 64]; RR = 0.93; 95% CI: 0.68 to 1.27; P = 0.63; adjusted RR = 0.97; 95% CI: 0.68 to 1.40), but was consistent with the expectation of a modest reduction in homocysteine levels. CONCLUSION: Homocysteine is an independent, graded risk factor for mortality. Homocysteine levels decreased modestly after the fortification of food with folic acid, but the effects on mortality were minor and likely attributable to other factors, indicating the need for more aggressive measures to reduce homocysteine-associated cardiovascular risk.

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PubMed2004

Toll-like receptor 4 gene Asp299Gly polymorphism is associated with reductions in vascular inflammation, angiographic coronary artery disease, and clinical diabetes.

BACKGROUND: Coronary artery disease (CAD) and, increasingly, diabetes are recognized as having an inflammatory basis. Membrane toll-like receptors (TLRs) activate signaling pathways that up-regulate inflammation. We evaluated whether the Asp299Gly polymorphism in the TLR4 gene, which impairs inflammatory responses, is associated with reduced vascular inflammation (assessed by C-reactive protein [CRP]) and a decreased risk for CAD and diabetes. METHODS: 1894 patients without acute myocardial infarction undergoing coronary angiography were studied. Genotyping was performed by real-time polymerase chain reaction. CAD was defined as >or=70% stenosis. Diabetes was diagnosed by patients' referring physicians. CRP was measured by fluorescence polarization immunoassay. Regression analyses adjusted for traditional cardiac risk factors. RESULTS: Patients averaged 64 +/- 11 years of age, and 69% were male. Asp299Gly genotype frequencies were: AA = 0.911 (n = 1725), AG = 0.086 (n = 164), and GG = 0.003 (n = 5), in keeping with Hardy-Weinberg equilibrium. CRP was lower among G-allele carriers (median = 1.11 mg/dL) than wild-type (AA) subjects (1.23 mg/dL, adjusted P = .044). G-allele carriers also had a lower prevalence of CAD (65% vs. 73%, OR = 0.67, CI = 0.46-0.99, adjusted P = .048) and diabetes (11% vs. 18%, OR = 0.63, CI = 0.42-0.95, adjusted P = .029), which persisted in multivariate logistic regression analyses. 299Gly carriage did not affect clinical outcomes nor interact with statin therapy. CONCLUSIONS: The TLR4 299Gly allele was associated with reduced CRP levels and, in parallel, a decreased risk of angiographic CAD and clinical diabetes. These findings suggest that down-regulation of innate immune responsiveness could beneficially modify CAD and diabetes risk and might provide a novel basis for genetic risk stratification and therapeutic targeting.

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PubMed2004

Cytomegalovirus stimulated mRNA accumulation and cell surface expression of the oxidized LDL scavenger receptor, CD36.

OBJECTIVE: Cytomegalovirus (CMV) has been epidemiologically associated with multiple disease processes including coronary, carotid and cardiac graft atherosclerosis. An early initiating event in atherogenesis is the uptake by macrophages of oxidized low-density lipoproteins (OxLDL) via the scavenger receptor, CD36. Because CMV can activate host-cell gene transcription, we hypothesized that CMV may upregulate CD36 expression. METHODS AND RESULTS: THP-1 monocyte/macrophage cells were treated with Davis strain CMV and cell surface CD36 expression measured by flow cytometry. Virus challenge increased the percentage of cells expressing CD36 from 21.8 +/- 1.7 to 48.2 +/- 4.0% (mean +/- S.D. for three experiments, P=0.0005); CD36 mRNA accumulation was increased by CMV treatment as determined by reverse transcription-polymerase chain reaction. Viral challenge also upregulated the mitogen-activated protein kinase p38; further, the specific p38 inhibitor, SB203580, reversed the CMV-induced CD36 cell surface expression from 57.2% of cells to baseline levels (29.0 and 30.1% for SB203580 treated and control cells, respectively; P=0.001). Treatment with virus also stimulated uptake of OxLDL: microscopically, virus-treated cells had a mean of 32 +/- 4.0 lipid vacuoles compared with 20 +/- 1.3 for control cells (P=0.01). CONCLUSIONS: These findings suggest that CMV-induced CD36 expression is one mechanism through which CMV may promote atherosclerosis. Other CMV-associated atherogenic mechanisms may exist; additional investigation is necessary.

CD36 Antigens↗
PubMed2004

A common variant of the AMPD1 gene predicts improved survival in patients with ischemic left ventricular dysfunction.

BACKGROUND: A recent retrospective study suggested that the adenosine monophosphate deaminase (AMPD)-1 gene variant C34T predicts outcome in heart failure patients. This variant might lead to ischemic preconditioning by increasing tissue adenosine. We tested whether the survival benefit of C34T occurs preferentially in the setting of ischemic left ventricular dysfunction. METHODS AND RESULTS: A consecutive cohort of patients (n=390) with left ventricular ejection fraction <40% was evaluated. In the ischemic patient subgroup (n=210) multivariate analysis identified AMPD1 T allele carriage (hazard ratio=0.43, confidence interval=0.20-0.94, P=.035) as an independent predictor of transplant-free cardiovascular survival. No benefit was found in the nonischemic group although the number of events was too small to reliably exclude a benefit by genotype. CONCLUSION: The AMPD1 C34T polymorphism influences transplant-free cardiovascular survival in the setting of ischemic left ventricular dysfunction.

AMP Deaminase↗
PubMed2003

Statin therapy interacts with cytomegalovirus seropositivity and high C-reactive protein in reducing mortality among patients with angiographically significant coronary disease.

BACKGROUND: Seropositivity to cytomegalovirus (CMV) and elevated C-reactive protein (CRP) may jointly predict increased mortality rates in patients with coronary artery disease (CAD). Therapy with statins reduces lipid levels but may also have other beneficial (eg, antiinflammatory) effects. This study prospectively evaluated the effect of statins on CMV-and CRP-associated death among patients with significant, angiographically defined CAD. METHODS AND RESULTS: We monitored 2315 patients with angiographically significant CAD (stenosis > or =70%) for an average of 2.4 years (maximum, 5.8 years). Anti-CMV IgG antibody levels and CRP concentrations were measured at baseline, and statin prescription was recorded. As previously reported, mortality rate was higher for CMV seropositivity (+) with high CRP (hazard ratio [HR], 2.0) and lower for statins (HR, 0.50). Compared with CMV(-)/low CRP (mortality rate, 5% with statin versus 4% without statin), the protective effect of statin therapy was markedly greater for CMV(+)/low CRP (mortality rate, 2% versus 7%; HR, 0.44; 95% CI, 0.16 to 1.3), CMV negative (-)/high CRP (mortality rate, 1% versus 8%; HR, 0.16), and CMV(+)/high CRP (mortality rate, 6% versus 17%; HR, 0.42; 95% CI, 0.25 to 0.70). After adjustment, interactions were found for statin therapy with CMV(+)/low CRP (P for interaction=0.065), CMV(-)/high CRP (P for interaction=0.051), and CMV(+)/high CRP (P for interaction=0.024). CONCLUSIONS: The survival benefit of statins interacted with CMV seropositivity and high CRP to significantly reduce mortality rates among patients with CAD. This finding supports the hypothesis that statins have beneficial, "lipid-independent," antiinflammatory effects. The mechanism of statin benefit associated with CMV seropositivity remains to be determined.

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PubMed2003

Effect of fasting glucose levels on mortality rate in patients with and without diabetes mellitus and coronary artery disease undergoing percutaneous coronary intervention.

BACKGROUND: Diabetes mellitus (DM) is predictive of increased mortality for patients with coronary artery disease (CAD). To what extent this risk extends below the diabetic threshold (fasting glucose level [FG] <126 mg/dL) is uncertain. METHODS: The study objective was to determine the risk associated with FG in a prospectively assembled cohort of 1612 patients with CAD who were undergoing percutaneous coronary intervention (PCI) and had a FG measured or a clinical diagnosis of DM (CDM). Patients were grouped as: CDM; no CDM, but FG > or =126 mg/dL (ADA-DM); impaired FG, 110-125 mg/dL (IFG); or normal FG, <110 mg/dL (NFG). Survival was assessed for 2.8 +/- 1.2 years. RESULTS: The average patient age was 62 +/- 12 years; 74% of the patients were men. Diagnostic frequencies were: CDM, 24%; ADA-DM, 18%; IFG, 19%; and NFG, 39%. Mortality rates were greater for patients in the CDM (44/394 [11.2%], P <.0001), ADA-DM (27/283 [9.5%], P <.001), and IFG (20/305 [6.6%], P =.04) groups than patients in the NFG group(12/630 [1.9%]). Independent receiver operating characteristic analysis chose FG > or =109 mg/dL as the best cutoff for increased risk (sensitivity, 81%; specificity, 51%). After adjustment with Cox regression analysis, CDM (hazard ratio [HR] = 5.0; 95% CI, 2.6-9.6; P <.001), ADA-DM (HR, 4.1; 95% CI, 2.1-8.2; P <.001), and IFG status (HR, 3.2; 95% CI, 1.5-6.5; P =.002) remained independent predictors of mortality. CONCLUSIONS: Prognostically significant abnormalities of FG are much more prevalent (61%) than expected in patients with CAD who are undergoing PCI. Despite revascularization, the associated mortality risk of even mild elevations in FG is substantial, emphasizing the importance of early detection and treatment of glycemia-related risk.

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PubMed2003

The cholesteryl ester transfer protein Taq1B gene polymorphism predicts clinical benefit of statin therapy in patients with significant coronary artery disease.

BACKGROUND: Cholesteryl ester transfer protein (CETP) regulates plasma lipid distribution. A polymorphism in the CETP gene (Taq1B) is associated with CETP activity, HDL concentration, atherosclerosis progression, and response to statins, and may influence cardiovascular (CV) events. We studied CETP Taq1B genotype, plasma HDL, and clinical events among all patients and patients stratified by statin treatment. METHODS: Consenting patients (n = 2531) with significant coronary artery disease (> or =1 lesion of > or =70% stenosis) undergoing coronary arteriography were genotyped, grouped by statin prescription at hospital discharge, and prospectively followed-up for the outcomes of all-cause mortality and myocardial infarction. RESULTS: CETP Taq1B genotype frequencies were: B1B1, 32.9%; B1B2, 50.3%; and B2B2 16.8%. Plasma HDL was reduced for B1B1 patients (33 +/- 12 mg/dL, vs 36 +/- 13 mg/dL and 36 +/- 13 mg/dL for B1B2 and B2B2, respectively, P for trend =.003). Overall, event rates did not differ between genotypes. Event rates were similar among untreated (24.8%) and statin-treated (24.2%) B1 homozygotes (P = NS); statins significantly reduced events for B1B2 subjects (28.0% vs 21.0%, P =.009) and for B2B2 subjects (26.4% vs 17.4%, P =.048). Therapeutic benefit for B2 carriers remained after adjustment for covariates, and regression interaction analysis showed that B2 carriers experienced reduced events (relative risk [RR] 0.62, 95% CI 0.45-0.86), but statins did not benefit those with B1B1 (RR 1.09, 95% CI 0.70-1.7; P for interaction =.02). Findings were similar for the end point of death alone, although a modest benefit was seen in B1B1 patients (RR 0.67, P =.10), in addition to the strong benefit for B1B2 (RR 0.53, P =.001) and B2B2 (RR 0.28, P =.001). CONCLUSIONS: The CETP Taq1B polymorphism is associated with differential HDL levels but no significant differential in CV risk in the absence of treatment. Importantly, however, CV event reduction by statin therapy is substantially enhanced in the presence of a B2 allele. Our findings suggest, for the first time, the potential of CETP Taq1B genotyping to enable more effective, pharmacogenetically directed therapy.

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PubMed2003

Cardiovascular pharmacogenomics: current status, future prospects.

Pharmacogenomics is a field dedicated to exploring the contribution of genetics to interindividual variability in drug response. A goal of cardiovascular pharmacogenomics is to guide cardiovascular drug development and selection so as to optimize therapeutic benefit and minimize the potential for toxicity. Genetic-based differences in drug metabolism have long been recognized but just now are on the verge of wider clinical application. Differences in efficacy of cardiovascular drugs (independent of drug concentration) based on common genetic variations (polymorphisms) only recently have begun to be explored, but the potential for clinical application appears promising. Examples are presented of important pharmacodynamic effects of genetic variants on several drugs, including those in antiarrhythmic, reninangiotensin, beta-blocker, lipid-lowering, and antithrombotic classes. Principles of pharmacogenomics applied to drug metabolism are discussed that are relevant to drug development and clinical use, and examples are given for CYP450 phase I enzymes, phase II enzymes, and drug transporters. Challenges in establishing true pharmacogenetic associations are discussed, and current and future clinical potential is summarized. Rapid research progress and initial clinical applications with pharmacogenomics are foreseen in the near future.

Adrenergic beta-Antagonists↗
PubMed2002

Statin therapy is associated with reduced mortality across all age groups of individuals with significant coronary disease, including very elderly patients.

OBJECTIVES: This study evaluated the effect of statin therapy on mortality in individuals with significant coronary artery disease (CAD) stratified by age. BACKGROUND: Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) significantly reduce morbidity and mortality in individuals with CAD. Unfortunately, the large statin trials excluded individuals over 80 years old, and it is therefore unknown whether very elderly individuals benefit from statins as do younger individuals. METHODS: A cohort of 7,220 individuals with angiographically defined significant CAD (> or =70%) was included. Statin prescription was determined at hospital discharge. Patients were followed up for 3.3 +/- 1.8 years (maximum 6.8). Patients were grouped by age (<65, 65 to 79, and > or =80 years) to determine whether statin therapy reduced mortality in an age-dependent manner. RESULTS: Average age was 65 +/- 12 years; 74% were male; and 31% had a postmyocardial infarction status. Overall mortality was 16%. Elderly patients were significantly less likely to receive statins than younger patients (> or =80 years: 19.8%; 65 to 79 years: 21.1%; <65 years: 28.0%; p < 0.001). Mortality was decreased among statin recipients in all age groups: > or =80 years: 29.5% among patients not taking a statin versus 8.5% of those taking a statin (adjusted hazard ratio [HR] 0.50, p = 0.036); 65 to 79 years: 18.7% vs. 6.0% (HR 0.56, p < 0.001); and <65 years: 8.9% vs. 3.1% (HR 0.70, p = 0.097). CONCLUSIONS: Statin therapy is associated with reduced mortality in all age groups of individuals with significant CAD, including very elderly individuals. Although older patients were less likely to receive statin therapy, they received a greater absolute risk reduction than younger individuals. More aggressive statin use after CAD diagnosis may be indicated, even in older patients.

Adult↗
PubMed2002

Greater pathogen burden but not elevated C-reactive protein increases the risk of clinical restenosis after percutaneous coronary intervention.

BACKGROUND: Restenosis after percutaneous coronary intervention (PCI) constitutes a serious complication in the treatment of cardiovascular disease, but known risk factors do not fully account for the observed restenosis risk. Preliminary studies of infection or inflammation in restenosis report varied results. We tested whether C-reactive protein (CRP) or pathogen burden (seropositivity to 0, 1, 2, or 3 pathogens, of Chlamydia pneumoniae [Cpn], cytomegalovirus [CMV], or Helicobacter pylori [Hpy]) predict clinical restenosis after percutaneous coronary intervention (PCI). METHODS: Blood samples were collected from 415 patients undergoing PCI, and levels of plasma CRP and antibodies to Cpn, CMV, and Hpy were measured. The patient's medical history, demographics, and procedural data were recorded. Patient end points were determined for as long as 6 months as a means of evaluating the incidence of clinical restenosis and major adverse cardiac events. RESULTS: The average patient age was 62 years, and 80% of patients were male. Fifty-eight patients (14%) experienced clinical restenosis, whereas 17 patients (4%) died or had an acute myocardial infarction. After adjusting for 19 possible predictors, we found the pathogen burden (P-trend =.04, adjusted odds ratio [OR] 1.5 per number of pathogens) and minimum luminal diameter (P =.003, OR 1.8 per mm decrease) to be significant predictors of clinical restenosis. Male sex was a nonsignificant predictor of restenosis (P =.06, OR 2.2), but CRP was not significant after adjustment (P-trend =.10, OR 0.73 per tertile). CONCLUSION: Pathogen burden was associated with clinical coronary restenosis, an association that deserves further exploration and evaluation. CRP, a marker of inflammation, was not associated with an increased risk of restenosis.

Aged↗