Joseph P. McConnell

Criteria for Evaluation of Novel Markers of Cardiovascular Risk A Scientific Statement From the American Heart Association

There is increasing interest in utilizing novel markers of cardiovascular disease risk, and consequently, there is a need to assess the value of their use. This scientific statement reviews current concepts of risk evaluation and proposes standards for the critical appraisal of risk assessment methods. An adequate evaluation of a novel risk marker requires a sound research design, a representative at-risk population, and an adequate number of outcome events. Studies of a novel marker should report the degree to which it adds to the prognostic information provided by standard risk markers. No single statistical measure provides all the information needed to assess a novel marker, so measures of both discrimination and accuracy should be reported. The clinical value of a marker should be assessed by its effect on patient management and outcomes. In general, a novel risk marker should be evaluated in several phases, including initial proof of concept, prospective validation in independent populations, documentation of incremental information when added to standard risk markers, assessment of effects on patient management and outcomes, and ultimately, cost-effectiveness.

Endurance Exercise as a Countermeasure for Aging

OBJECTIVE— We determined whether reduced insulin sensitivity, mitochondrial dysfunction, and other age-related dysfunctions are inevitable consequences of aging or secondary to physical inactivity. RESEARCH DESIGN AND METHODS— Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp and ATP production in mitochondria isolated from vastus lateralis biopsies of 42 healthy sedentary and endurance-trained young (18–30 years old) and older (59–76 years old) subjects. Expression of proteins involved in fuel metabolism was measured by mass spectrometry. Citrate synthase activity, mitochondrial DNA (mtDNA) abundance, and expression of nuclear-encoded transcription factors for mitochondrial biogenesis were measured. SIRT3, a mitochondrial sirtuin linked to lifespan-enhancing effects of caloric restriction, was measured by immunoblot. RESULTS— Insulin-induced glucose disposal and suppression of endogenous glucose production were higher in the trained young and older subjects, but no age effect was noted. Age-related decline in mitochondrial oxidative capacity was absent in endurance-trained individuals. Although endurance-trained individuals exhibited higher expression of mitochondrial proteins, mtDNA, and mitochondrial transcription factors, there were persisting effects of age. SIRT3 expression was lower with age in sedentary but equally elevated regardless of age in endurance-trained individuals. CONCLUSIONS— The results demonstrate that reduced insulin sensitivity is likely related to changes in adiposity and to physical inactivity rather than being an inevitable consequence of aging. The results also show that regular endurance exercise partly normalizes age-related mitochondrial dysfunction, although there are persisting effects of age on mtDNA abundance and expression of nuclear transcription factors and mitochondrial protein. Furthermore, exercise may promote longevity through pathways common to effects of caloric restriction.

Atorvastatin Inhibits Hypercholesterolemia-Induced Cellular Proliferation and Bone Matrix Production in the Rabbit Aortic Valve

Background—Despite the common occurrence of aortic stenosis, the cellular causes of the disorder are unknown, in part because of the absence of experimental models. We hypothesized that atherosclerosis and early bone matrix expression in the aortic valve occurs secondary to experimental hypercholesterolemia and that treatment with atorvastatin modifies this transformation. Methods and Results—To test this hypothesis, we developed an experimental hypercholesterolemic rabbit model. New Zealand White rabbits (n=48) were studied: group 1 (n=16), normal diet; group 2 (n=16), 1% (wt/wt) cholesterol diet; and group 3 (n=16), 1% (wt/wt) cholesterol diet plus atorvastatin (3 mg/kg per day). The aortic valves were examined with hematoxylin and eosin stain, Masson trichrome, macrophage (RAM 11), proliferation cell nuclear antigen (PCNA), and osteopontin immunostains. Cholesterol and highly sensitive C-reactive protein (hsCRP) serum levels were obtained by standard assays. Computerized morphometry and digital image analysis were performed for quantifying PCNA (% area). Electron microscopy and immunogold labeling were performed for osteopontin. Semiquantitative RT-PCR was performed for the osteoblast bone markers [alkaline phosphatase, osteopontin, and osteoblast lineage-specific transcription factor (Cbfa-1)]. There was an increase in cholesterol, hsCRP, PCNA, RAM 11, and osteopontin and osteoblast gene markers (alkaline phosphatase, osteopontin, and Cbfa-1) in the cholesterol-fed rabbits compared with control rabbits. All markers except hsCRP were reduced by atorvastatin. Conclusions—These findings of increased macrophages, PCNA levels, and bone matrix proteins in the aortic valve during experimental hypercholesterolemia provide evidence of a proliferative atherosclerosis–like process in the aortic valve associated with the transformation to an osteoblast-like phenotype that is inhibited by atorvastatin.

Relationships between disease activity and serum and fecal biomarkers in patients with Crohn's disease.

BACKGROUND & AIMS The quantitative relationships between instruments and assays that measure clinical, endoscopic, and biologic disease activity in patients with Crohns disease are poorly characterized. This study evaluated the correlations between the Crohns Disease Activity Index (CDAI), the Simple Endoscopic Score for Crohns Disease (SES-CD), serum high-sensitivity C-reactive protein (hsCRP) (both phenotype and genotype) and interleukin-6 (IL-6), and fecal calprotectin and lactoferrin. METHODS A total of 164 patients with Crohns disease undergoing colonoscopy were enrolled. The CDAI and SES-CD scores, serum hsCRP and IL-6, CRP and IL-6 genotypes, and fecal calprotectin and lactoferrin were measured. RESULTS There were no significant associations between the CDAI and SES-CD scores (Spearman rank correlation coefficient, 0.15) or between the CDAI scores and the serum concentrations of hsCRP and IL-6, or the fecal concentrations of calprotectin and lactoferrin. In contrast, the serum hsCRP and IL-6 concentrations and the fecal calprotectin and lactoferrin concentrations were significantly higher in patients with more severe endoscopic disease activity (SES-CD score > 7 points) (P < .001 for all comparisons). The CRP 717 mutant homozygote and heterozygote status was associated with significantly lower concentrations of hsCRP (P = .02). There was a trend toward higher hsCRP concentrations in the CRP 286 heterozygous adenine mutant-type mutant genotype, but this did not reach statistical significance. CONCLUSIONS Serum and fecal biomarker concentrations are associated with endoscopic but not clinical disease activity in patients with Crohns disease. Stimulated hsCRP concentration is affected significantly by select genetic polymorphisms.

Survival in patients with primary systemic amyloidosis and raised serum cardiac troponins

Patients with primary systemic amyloidosis that affects the heart have a poor outlook. Cardiac troponins T and I (cTnT, cTnI) are highly specific and sensitive biomarkers of myocardial injury. Values of these troponins provide quantitative information about the disease. We retrospectively assessed 261 patients newly diagnosed as having primary systemic amyloidosis. Median survival for patients with detectable cTnT and cTnI (6 and 8 months, respectively), was worse than that for those with undetectable values (22 and 21 months, respectively). Median and 25th and 75th percentile values for cTnT were 0.024 microg/L, less than 0.01 microg/L, and 0.084 microg/L, and for cTnI were 0.1 microg/L, 0.05 microg/L, and 0.24 microg/L, respectively. After multivariate analysis, cTnT proved a better predictor of survival than cTnI.

Apolipoprotein B and Cardiovascular Disease Risk: Position Statement from the AACC Lipoproteins and Vascular Diseases Division Working Group on Best Practices

BACKGROUND Low-density lipoprotein cholesterol (LDL-C) has been the cornerstone measurement for assessing cardiovascular risk for nearly 20 years. CONTENT Recent data demonstrate that apolipoprotein B (apo B) is a better measure of circulating LDL particle number (LDL-P) concentration and is a more reliable indicator of risk than LDL-C, and there is growing support for the idea that addition of apo B measurement to the routine lipid panel for assessing and monitoring patients at risk for cardiovascular disease (CVD) would enhance patient management. In this report, we review the studies of apo B and LDL-P reported to date, discuss potential advantages of their measurement over that of LDL-C, and present information related to standardization. CONCLUSIONS In line with recently adopted Canadian guidelines, the addition of apo B represents a logical next step to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) and other guidelines in the US. Considering that it has taken years to educate physicians and patients regarding the use of LDL-C, changing perceptions and practices will not be easy. Thus, it appears prudent to consider using apo B along with LDL-C to assess LDL-related risk for an interim period until the superiority of apo B is generally recognized.

Association Between Lipoprotein-Associated Phospholipase A2 and Cardiovascular Disease: A Systematic Review

OBJECTIVE To estimate the association between plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) levels and cardiovascular disease (CVD). METHODS We searched MEDLINE (January 1, 1985, through September 30, 2006), the Cochrane library (from inception through 2006), conference proceedings, and reference sections of obtained articles and contacted experts for unpublished studies. Eligible studies were cohorts with 1 year or more of follow-up or case-control designs that provided risk estimates for CVD according to blood levels of Lp-PLA2 that were unadjusted or adjusted for conventional CVD risk factors. We used random-effects meta-analysis to estimate the association between Lp-PLA2 and CVD risk and conducted preplanned subgroup analyses to identify risk-subgroup interactions that could explain between-study differences. RESULTS We found 14 eligible studies (N = 20,549 patients) that reported either Lp-PLA2 plasma activity (n = 5) or an immunoassay that measured the plasma concentration (n = 9). The meta-analytic estimate from the unadjusted odds ratio for the association between elevated Lp-PLA2 levels and CVD risk was 1.51 (95% confidence interval, 1.30-1.75) and from the odds ratio adjusted for conventional CVD risk factors was 1.60 (95% confidence interval, 1.36-1.89). Differences in study methods explained differences in results across studies. CONCLUSIONS Lipoprotein-associated phospholipase A2 is significantly associated with CVD. The risk estimate appears to be relatively unaffected by adjustment for conventional CVD risk factors. Measurement of Lp-PLA2 may be useful in CVD risk stratification. In addition, Lp-PLA2 may represent a potential therapeutic target for CVD risk reduction.

Relationship of IgG and IgM autoantibodies to oxidized low density lipoprotein with coronary artery disease and cardiovascular events

The relationship between autoantibodies to oxidized low density lipoprotein (OxLDL) and coronary artery disease (CAD) remains controversial. IgM and IgG OxLDL autoantibodies to malondialdehyde (MDA)-modified LDL, copper oxidized low density lipoprotein (CuOxLDL), and oxidized cholesterol linoleate (OxCL), as well as apolipoprotein B-100 immune complexes (apoB-ICs), were measured in 504 patients undergoing clinically indicated coronary angiography. Patients were followed for cardiovascular events for a median of 4 years. In univariate analysis, IgM OxLDL autoantibodies and IgM apoB-ICs were inversely associated with the presence of angiographically determined CAD, whereas IgG OxLDL autoantibodies and IgG apoB-ICs were positively associated. In logistic regression analysis, compared with the first quartile, patients in the fourth quartile of IgM OxLDL autoantibodies and apoB-ICs showed a lower probability of angiographically determined CAD (>50% diameter stenosis). Odds ratios and (95% confidence intervals) were as follows: MDA-LDL, 0.51 (0.32–0.82; P = 0.005); CuOxLDL, 0.63 (0.39–1.01; P = 0.05); OxCL, 0.63 (0.39–1.01; P = 0.05); and apoB-IC, 0.55 (0.34–0.88; P = 0.013). These relationships were accentuated in the setting of hypercholesterolemia, with the highest IgM levels showing the lowest risk of CAD for the same level of hypercholesterolemia. Multivariable analysis revealed that neither IgM or IgG OxLDL autoantibodies nor apoB-ICs were independently associated with angiographically determined CAD or cardiovascular events. In conclusion, IgG and IgM OxLDL biomarkers have divergent associations with CAD in univariate analysis but are not independent predictors of CAD or clinical events.

Local Production of Lipoprotein-Associated Phospholipase A2 and Lysophosphatidylcholine in the Coronary Circulation Association With Early Coronary Atherosclerosis and Endothelial Dysfunction in Humans

Background— Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a novel marker and participant in vascular inflammation. Inflammation also is associated with coronary atherosclerosis. We tested the hypothesis that local coronary production of Lp-PLA2 is enhanced in patients with early coronary atherosclerosis and associated with local endothelial function. Methods and Results— Coronary angiography, blood flow, flow reserve, endothelial function assessment, and intravascular ultrasound with volumetric analysis were performed in 15 patients with mild coronary atherosclerosis and in 15 control subjects. Plasma samples were collected simultaneously from the left main coronary artery and coronary sinus for measurement of Lp-PLA2, lysophosphatidylcholine (a product of Lp-PLA2), and C-reactive protein. Hemodynamic parameters and cholesterol were similar in both groups. Arterial Lp-PLA2 levels were similar in patients and control subjects: 225 ng/mL (interquartile range [IQR], 196 to 273 ng/mL) versus 221 ng/mL (IQR, 177 to 294 ng/mL). Lp-PLA2 net production in the coronary circulation was higher in patients compared with control subjects: 519 ng/min (IQR, 198 to 1276 ng/min) versus −529 ng/min (IQR, −872 to −79 ng/min; P=0.001) and correlated with percent atheroma volume (rs=0.37, P=0.04). Net production of lysophosphatidylcholine was higher in patients compared with control subjects: 199 ng/min (IQR, −592 to 470 ng/min) versus −505 ng/min (IQR, −1119 to 0 ng/min; P=0.03) and correlated with coronary endothelial dysfunction (rs=0.5, P=0.005). C-reactive protein was not significantly different between the groups. Conclusions— Early coronary atherosclerosis in humans is characterized by local production of Lp-PLA2. Local coronary production of lysophosphatidylcholine, the active product of Lp-PLA2, is associated with endothelial dysfunction. These results support the role for Lp-PLA2 in the mechanism of regional vascular inflammation and atherosclerosis in humans.

Nutrition Assessment of Patients With Inflammatory Bowel Disease

BACKGROUND Malnutrition among inflammatory bowel disease (IBD) subjects is well documented in the literature and may arise from factors including inadequate dietary intake, malabsorption, and disease activity. The aims of this present study were to complete a comprehensive nutrition assessment of IBD subjects. METHODS One hundred twenty-six consecutive adults with IBD completed anthropometric measures, 4-day food-record assessments, and biochemical markers of nutrition. RESULTS A high prevalence of inadequate nutrient consumption was observed: vitamin E (63%), vitamin D (36%), vitamin A (26%), calcium (23%), folate (19%), iron (13%), and vitamin C (11%). Several biochemical deficiencies were also observed. The prevalence of subnormal serum levels was hemoglobin (40%), ferritin (39.2%), vitamin B(6) (29%), carotene (23.4%), vitamin B(12) (18.4%), vitamin D (17.6%), albumin (17.6%), and zinc (15.2%). Dietary intake was not correlated with serum levels in all instances; there was a highly significant correlation between diet and serum values of vitamin B(12), folate, and vitamin B(6) for all IBD subjects, independent of disease activity, and for vitamin D among all IBD subjects in remission. CONCLUSIONS Subjects with IBD have a high rate of iron deficiency and anemia, which are most likely not secondary to diet. Supplementing with iron should be warranted only if a true iron deficiency exists. The routine evaluation of serum vitamin B(6) and vitamin D levels is recommended. Routine multivitamin supplementation is warranted in IBD in view of numerous dietary and biochemical deficiencies observed among adult IBD subjects. Even if subjects with IBD seem to be well nourished, they may harbor vitamin/mineral deficiencies.