Center-related Bias in MELD Scores Within a Liver Transplant UNOS Region: A Call for Standardization.

BACKGROUND: Model for End-Stage Liver Disease (MELD) score-based liver transplant allocation was implemented as a fair and objective measure to prioritize patients based upon disease severity. Accuracy and reproducibility of MELD is an essential assumption to ensure fairness in organ access. We hypothesized that variability in laboratory methodology between centers could impact allocation scores for individuals on the transplant waiting list. METHODS: Aliquots of 30 patient serum samples were analyzed for creatinine, bilirubin, and sodium in all transplant centers within United Network for Organ Sharing (UNOS) region 9. Descriptive statistics, intraclass correlation coefficients (ICCs), and linear mixed-effects regression were used to determine the relationship between center, bilirubin, and calculated MELD-sodium (MELD-Na) score. RESULTS: The mean MELD-Na score per sample ranged from 14 to 38. The mean range in MELD-Na per sample was 3 points, but 30% of samples had a range of 4-6 points. Correlation plots and intraclass correlation coefficient analysis confirmed bilirubin interfered with creatinine, with worsening agreement in creatinine at high bilirubin levels. Center and bilirubin were independently associated with creatinine reported in mixed-effects models. Unbiased hierarchical clustering suggested that samples from specific centers have consistently higher creatinine and MELD-Na values. CONCLUSIONS: Despite implementation of creatinine standardization, centers within a single UNOS region report clinically significant differences in MELD-Na on an identical sample, with differences of up to 6 points in high MELD-Na patients. The bias in MELD-Na scores based upon center choice within a region should be addressed in the current efforts to eliminate disparities in liver transplant access.

Low Serum Paraoxonase-1 Activity Associates with Incident Cardiovascular Disease Risk in Subjects with Concurrently High Levels of High-Density Lipoprotein Cholesterol and C-Reactive Protein.

Paroxonase-1 (PON1) is a key enzyme that inhibits low-density lipoprotein oxidation and consequently atherogenesis. Here, we assessed whether low serum PON1 activity associates with incident cardiovascular disease (CVD) in subjects with high levels of high-density cholesterol (HDL-C) and C-reactive protein (CRP), a marker of low-grade systemic inflammation. Cox proportional-hazards modeling of incident CVD risk (11 years mean follow-up) adjusted for relevant clinical and biomarker covariates was performed on a population-based study (N = 7766) stratified into three groups: low CRP-(LR; event rate 4.9%); low HDL-C/high CRP-(HR1; event rate 14.4%); and high HDL-C/high CRP-(HR2; event rate 7.6%). Modeling results for PON1 activity in HR2 were significant and robust (hazard ratio/SD unit-0.68, 95% CI 0.55-0.83, p = 0.0003), but not so for LR and HR1. Analyses in HR2 of the interaction of PON1 with HDL-C, apoA-I, apoA-II, and apoE levels were significant only for PON1 with apoE (hazard ratio-1.77, 95% CI 1.29-2.41, p = 0.0003). Subsequent subgroup analysis revealed inverse risk dependence for apoE at low PON1 levels. In conclusion, in a population-based study of subjects with concurrently high HDL-C and CRP levels, low serum PON1 activity associates with incident CVD risk with risk accentuated at low apoE levels.

Plasma ApoE elevations are associated with NAFLD: The PREVEND Study.

Non-alcoholic fatty liver disease (NAFLD) is featured by increased plasma very low density lipoproteins (VLDL). The extent to which plasma apolipoprotein E (ApoE) levels are elevated in NAFLD is unclear. We determined whether plasma ApoE is elevated in subjects with suspected NAFLD. Plasma ApoE and genotypes were determined in 6,762 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. A Fatty Liver Index (FLI) ≥ 60 was used as a proxy of NAFLD. A total of 1,834 participants had a FLI ≥ 60, which coincided with increased triglycerides, non-HDL cholesterol, ApoB and ApoE (all P<0.001). In multivariable linear regression analysis, plasma ApoE levels were positively associated with an elevated FLI when taking account of ApoE genotypes and other clinical and laboratory covariates (fully adjusted model: ß = 0.201, P<0.001). Stratified analysis for ApoE genotypes (ApoE ε3ε3 homozygotes, ApoE ε2 carriers, and ApoE ε3ε4 and ε4ε4 carriers combined), also showed positive associations of plasma ApoE levels with an elevated FLI in each group (all P<0.001). In conclusion, it is suggested that NAFLD is characterized by increased plasma ApoE levels, even when taking account of the various ApoE genotypes. Increased plasma ApoE may contribute to altered VLDL metabolism and to increased atherosclerosis susceptibility in NAFLD.

Compositional Features of HDL Particles Interact with Albuminuria to Modulate Cardiovascular Disease Risk.

Lipoproteins containing apolipoprotein B modify associations of elevated urinary albumin excretion (UAE) with cardiovascular disease (CVD). Additionally, it is known that elevated UAE alters high-density lipoprotein functionality. Accordingly, we examined whether HDL features might also modify UAE-associated CVD. Multivariable Cox proportional-hazards modeling was performed on participants of the PREVEND (Prevention of Renal and Vascular Endstage Disease) study at the baseline screening with standard lipid/lipoprotein analyses and, three-to-four years later (second screen), with nuclear magnetic resonance lipoprotein analyses focusing on HDL parameters including HDL particle (HDL-P) and apolipoprotein A-I concentrations. These were used with UAE and derived measures of HDL apoA-I content (apoA-I/HDL-C and apoA-I/HDL-P) in risk models adjusted for gender, age, apoB, diabetes, past CVD history, CRP and GFR. Interaction analysis was also performed. Baseline screening revealed significant associations inverse for HDL-C and apoA-I and direct for apoA-I/HDL-C. The second screening demonstrated associations inverse for HDL-P, large HDL-P, medium HDL-P, HDL size, and apoA-I/HDL-P. Significant interactions with UAE included apoA-I/HDL-C at the baseline screening, and apoA-I/HDL-P and medium HDL-P but not apoA-I/HDL-C at the second screening. We conclude that features of HDL particles including apoA-I/HDL-P, indicative of HDL apoA-I content, and medium HDL-P modify associations of elevated UAE with CVD risk.

Insulin resistance involvement in prevalence of familial dysbetalipoproteinemia in ε2ε2 subjects by Bayesian network modeling.

OBJECTIVE: Familial dysbetalipoproteinemia (FD) or Type III hyperlipoproteinemia is closely associated with the ε2ε2 genotype of the common APOE polymorphism although not all ε2 homozygotes develop FD indicating that additional factors play a role including insulin resistance (IR). The current study was undertaken to explore relationships and influences among factors, especially IR, that might elucidate FD progression pathways. METHODS: Bayesian network (BN) modeling, a probabilistic graphical exploratory data analysis tool that portrays relationships and influences among variables as simple diagrams, was applied to 52 e2e2 subjects. An algorithm based on apolipoprotein and lipid values identified 24 subjects having FD. BN modeling parameters included plasma apoE, HDL cholesterol (HDL-C), apolipoprotein A-I (apoA-I), apolipoprotein A-II (apoA-II), apoA-I/HDL-C ratio, apoA-II/HDL-C ratio, insulin, and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). RESULTS: Modeling resulted in twenty network graphs. Each graph revealed apoE and the apoA-II/HDL-C ratio as sole determinants of FD prevalence. BN results did not demonstrate a direct role for insulin and HOMA-IR. However, multiple graphs in the set did reveal indirect influence of IR on FD prevalence as conveyed through the apoA-II/HDL-C ratio; while all remaining graphs in the set demonstrated the apoA-II/HDL-C ratio as directly influencing insulin levels and HOMA-IR. For apoE, the other determinant of FD prevalence, results revealed no relationship with IR parameters. CONCLUSIONS: In so far as insulin levels and HOMA-IR are associated with IR in e2e2 subjects, IR may act indirectly in FD progression via the apoA-II/HDL-C ratio; and/or the apoA-II/HDL-C ratio acts directly to promote IR.

Roles of high apolipoprotein E blood levels and HDL in development of familial dysbetalipoproteinemia in ε2ε2 subjects.

OBJECTIVE: Familial dysbetalipoproteinemia (FD) or Type III hyperlipoproteinemia is a mixed hyperlipidemia closely associated with the ε2ε2 genotype of the common APOE polymorphism although not all homozygotes progress to FD. Unlike the polymorphism, few studies explore effects of apolipoprotein E (apoE) blood levels on FD development. Likewise, despite the known apoE2 lipoprotein binding preference for high-density lipoprotein (HDL); little work exists exploring HDL in FD. Accordingly, this study was undertaken to investigate potential roles in FD development for apoE and HDL. Additionally, insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) were investigated in view of reports linking insulin resistance to FD. METHODS: APOE genotyping and levels of apoE, apolipoprotein A-I (apoA-I), apolipoprotein A-II (apoA-II), insulin, HOMA-IR, lipids, and NMR lipoprotein analysis were determined in a cohort of healthy individuals (N=7169). A lipid-based algorithm identified FD in 24 of 52 e2e2 subjects. Logistic regression modeling assessed associations of FD development with measured variables. RESULTS: Univariate models revealed associations with FD significant and positive for apoE, apoA-II/apoA-I, apoA-I/HDL-C, apoA-II/HDL-C, and HOMA-IR. For HDL-C, association was significant but inverse. Results of multivariable models containing apoE with single parameters added revealed statistical significance only for the apoA-II/HDL-C ratio (OR 10.52, 95%CI 1.17-94.79, p=0.036) concurrent with significance for apoE (OR 2.21, 95%CI 1.06-4.65, p=0.035). Interaction was not demonstrated (p=0.36). NMR results revealed for FD versus nonFD subjects generally higher levels of VLDL and small HDL and for IDL few differences. CONCLUSION: High apoE and high apoA-II/HDL-C independently associate with FD development in ε2ε2 individuals.

Inflammatory markers modify the risk of recurrent coronary events associated with apolipoprotein A-I in postinfarction patients.

BACKGROUND: Laboratory findings have suggested that systemic and vascular inflammation can impair the antiatherogenic function of high-density lipoproteins (HDLs). However, evidence from population studies is sparse. OBJECTIVE: The objective of the study was to assess if blood inflammatory markers modify the risk of recurrent coronary events associated with apolipoprotein A-I (apoA-I) and HDL cholesterol (HDL-C) among postinfarction patients. METHODS: ApoA-I, HDL-C, and inflammatory markers (C-reactive protein [CRP], serum amyloid A (SAA), fibrinogen, von Willebrand factor [vWF], and D-dimer) were measured from blood samples of 1028 patients drawn 2 months after an index myocardial infarction (MI). Patients were followed up for the composite coronary endpoint (nonfatal MI, coronary death, or unstable angina) for an average of 26 months. Cox proportional hazard models were used to assess effect modifications for the association of apoA-I and HDL-C with coronary risk by each inflammatory marker. RESULTS: CRP significantly modified the risk of recurrent coronary events associated with apoA-I. Among the entire population, multivariable-adjusted hazard ratios associated with each standard deviation increase in apoA-I for those with low and high CRP levels were 0.89 and 1.35, respectively (P value for interaction = .008). vWF was a significant effect modifier of the apoA-I/coronary risk association only among diabetic patients (hazard ratios were 0.56 and 1.43, for diabetic patients with low and high vWF levels, respectively; P value for interaction = .002). No effect modification was observed for the HDL-C/coronary risk association. CONCLUSION: Among stable post-MI patients, CRP modified the risk of recurrent coronary events associated with apoA-I. VWF modified this association only among the diabetic subgroup.

Simultaneous interferometric measurement of linear coefficient of thermal expansion and temperature-dependent refractive index coefficient of optical materials.

Characterizing the thermal properties of optical materials is necessary for understanding how to design an optical system for changing environmental conditions. A method is presented for simultaneously measuring both the linear coefficient of thermal expansion and the temperature-dependent refractive index coefficient of a sample interferometrically in air. Both the design and fabrication of the interferometer is presented as well as a discussion of the results of measuring both a steel and a CaF2 sample.

Apolipoprotein E levels and apolipoprotein E genotypes in incident cardiovascular disease risk in subjects of the Prevention of Renal and Vascular End-stage disease study.

BACKGROUND: Apolipoprotein E (apoE) is a component of all major lipoprotein classes with multiple functions including clearance of circulating triglyceride-rich lipoprotein particles and hepatic production of triglyceride-rich lipoprotein, thus affording several avenues for apoE involvement in atherosclerosis development. ApoE has 3 isoforms (E2, E3, and E4) based on a common genetic polymorphism. Numerous studies have been performed assessing cardiovascular disease (CVD) risk relative to the 6 resulting genotypes; however, surprisingly, few studies have been performed assessing risk attributable to apoE plasma levels either alone or in addition also taking into account apoE genotypes. OBJECTIVE: To examine the role of apoE levels together with apoE genotypes on incident CVD risk in a large population-based cohort and also to afford preliminary characterization of atherogenic apoE-containing lipoprotein particles. METHODS: Cox multivariable proportional hazards modeling was performed on a cohort of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study as a function of apoE levels and apoE genotypes adjusted for age, gender, and past history of CVD. Further modeling was performed with single addition of clinical and biomarker parameters to elucidate the nature of apoE-associated risk. RESULTS: High apoE levels were demonstrated to be associated with CVD risk (hazard ratio per apoE standard deviation, 1.20; 95% confidence interval, 1.11-1.31; P < .0001) both overall and within the high-frequency apoE genotype groups (ε2ε3, ε3ε3, and ε3ε4). Only on addition of apoB-containing lipoprotein parameters to models, did apoE levels lose association with risk. CONCLUSIONS: ApoE levels positively associate with incident CVD risk with apoE-associated risk likely residing in apoB-containing lipoproteins.

Data in support of a central role of plasminogen activator inhibitor-2 polymorphism in recurrent cardiovascular disease risk in the setting of high HDL cholesterol and C-reactive protein using Bayesian network modeling.

Data is presented that was utilized as the basis for Bayesian network modeling of influence pathways focusing on the central role of a polymorphism of plasminogen activator inhibitor-2 (PAI-2) on recurrent cardiovascular disease risk in patients with high levels of HDL cholesterol and C-reactive protein (CRP) as a marker of inflammation, "Influences on Plasminogen Activator Inhibitor-2 Polymorphism-Associated Recurrent Cardiovascular Disease Risk in Patients with High HDL Cholesterol and Inflammation" (Corsetti et al., 2016; [1]). The data consist of occurrence of recurrent coronary events in 166 post myocardial infarction patients along with 1. clinical data on gender, race, age, and body mass index; 2. blood level data on 17 biomarkers; and 3. genotype data on 53 presumptive CVD-related single nucleotide polymorphisms. Additionally, a flow diagram of the Bayesian modeling procedure is presented along with Bayesian network subgraphs (root nodes to outcome events) utilized as the data from which PAI-2 associated influence pathways were derived (Corsetti et al., 2016; [1]).

Influences on plasminogen activator inhibitor-2 polymorphism-associated recurrent cardiovascular disease risk in patients with high HDL cholesterol and inflammation.

BACKGROUND AND AIMS: Evidence continues to accumulate that athero-protective effects of high-density lipoprotein (HDL) depend to some degree on effective HDL functionality and that such functionality can become degraded in the setting of chronic inflammation. To investigate this issue, we have studied a group of post-myocardial infarction patients with high levels of C-reactive protein as an indicator of chronic inflammation and with concurrently high levels of HDL cholesterol. For these patients we have demonstrated high-risk for recurrent cardiac events as well as a strong association of risk with a polymorphism of the gene (SERPINB2) for plasminogen activator inhibitor-2 (PAI-2) presumptively reflective of an important role for fibrinolysis in risk. However, additional processes might be involved. The current work sought to characterize processes underlying how PAI-2 might be involved in the generation of risk. METHODS: Multivariate population data were leveraged using Bayesian network modeling, a graphical probabilistic approach for knowledge discovery, to generate networks reflective of influences on PAI-2 polymorphism-associated risk. RESULTS: Modeling results revealed three individual networks centering on the PAI-2 polymorphism with specific features providing information relating to how the polymorphism might associate with risk. These included racial dependency, platelet clot initiation and propagation, oxidative stress, inflammation effects on HDL metabolism and coagulation, and induction and termination of fibrinolysis. CONCLUSIONS: Beyond direct association of a PAI-2 polymorphism with recurrent risk in post-myocardial infarction patients, results suggest that PAI-2 likely plays a key role leading to risk through multiple pathophysiologic processes. Such knowledge could potentially be valuable with individualization of patient care.

Insulin resistance predicts the risk for recurrent coronary events in post-infarction patients.

BACKGROUND: We investigated the risk for recurrent coronary events associated with insulin resistance in post-infarction patients from the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study. METHODS: The association between insulin resistance expressed by Homeostatic Model As-sessment 2 for Insulin Resistance (HOMA2-IR) and the risk for recurrent coronary events was investigated in a cohort of 1,032 patients evaluated 2 months after myocardial infarction (MI) with a follow-up of 26 months. The endpoint for the study was recurrent coronary event defined as cardiac death, nonfatal MI, or unstable angina, whichever occurred first. We used time dependent survival analysis and Cox proportional hazards regression method to determine the association between HOMA2 categorized as high > 75th percentile and endpoints after adjustment for relevant clinical covariates and series of thrombogenic and dyslipogenic factors. RESULTS: High HOMA2-IR defined as in fourth quartile (≥ 2.4) was associated with increased risk for recurrent coronary events (HR 1.44; CI 1.03-2.01; p = 0.03) after adjustment for the clinical covariates: age, gender, diabetes, prior MI, pulmonary congestion, coronary artery bypass grafting and percutaneous transluminal coronary angioplasty. The highest risk of cardiac events was observed in non-obese patients (body mass index [BMI] ≤ 30 kg/m2) with high HOMA2-IR (HR 1.5; CI 1.02-2.22; p = 0.038). The plasma level of plasminogen activa-tor inhibitor-1 was associated with higher risk for recurrent coronary events in patients with insulin resistance (HR 1.79; CI 1.05-3.03; p = 0.03, interaction p = 0.018). CONCLUSIONS: In conclusion, insulin resistance predicts recurrence of coronary events in post-infarction population. HOMA2-IR is better than BMI in stratifying risk of recurrent coronary events.

Apolipoprotein B attenuates albuminuria-associated cardiovascular disease in prevention of renal and vascular endstage disease (PREVEND) participants.

Whether urinary albumin excretion relates to higher levels of atherogenic apolipoprotein B fractions in the nondiabetic population is uncertain. Such a relationship could explain, in part, the association of elevated urinary albumin excretion with cardiovascular disease risk. We assessed the relationship of urinary albumin excretion with apolipoprotein B fractions and determined whether the association of elevated urinary albumin excretion with incident cardiovascular events is modified by high apolipoprotein B fraction levels. We performed a prospective study on 8286 nondiabetic participants (580 participants with cardiovascular disease; 4.9 years median follow-up time) with fasting lipids, apolipoprotein B, and urinary albumin excretion determined at baseline. With adjustment for sex and age, micro- and macroalbuminuria were associated with increased apolipoprotein B fractions (non-HDL cholesterol, LDL cholesterol, triglycerides, and apolipoprotein B). All four apolipoprotein B fractions modified associations of urinary albumin excretion with incident cardiovascular disease (hazard ratios for interaction terms ranged from 0.89 to 0.94 with 95% confidence intervals ranging from 0.84 to 0.99 and P values ranging from 0.001 to 0.02 by Cox proportional hazards modeling). These interactions remained present after additional adjustment for conventional risk factors, eGFR, cardiovascular history, and lipid-lowering and antihypertensive drug treatments. Such modification was also observed when urinary albumin excretion was stratified into normo-, micro-, and macroalbuminuria. We conclude that there is an association between elevated urinary albumin excretion and apolipoprotein B fraction levels and a negative interaction between these variables in their associations with incident cardiovascular events. Elevated urinary albumin excretion may share common causal pathways with high apolipoprotein B fractions in the pathogenesis of cardiovascular disease.

Plasminogen activator inhibitor-2 polymorphism associates with recurrent coronary event risk in patients with high HDL and C-reactive protein levels.

The objective of this work was to investigate whether fibrinolysis plays a role in establishing recurrent coronary event risk in a previously identified group of postinfarction patients. This group of patients was defined as having concurrently high levels of high-density lipoprotein cholesterol (HDL-C) and C-reactive protein (CRP) and was previously demonstrated to be at high-risk for recurrent coronary events. Potential risk associations of a genetic polymorphism of plasminogen activator inhibitor-2 (PAI-2) were probed as well as potential modulatory effects on such risk of a polymorphism of low-density lipoprotein receptor related protein (LRP-1), a scavenger receptor known to be involved in fibrinolysis in the context of cellular internalization of plasminogen activator/plansminogen activator inhibitor complexes. To this end, Cox multivariable modeling was performed as a function of genetic polymorphisms of PAI-2 (SERPINB, rs6095) and LRP-1 (LRP1, rs1800156) as well as a set of clinical parameters, blood biomarkers, and genetic polymorphisms previously demonstrated to be significantly and independently associated with risk in the study population including cholesteryl ester transfer protein (CETP, rs708272), p22phox (CYBA, rs4673), and thrombospondin-4 (THBS4, rs1866389). Risk association was demonstrated for the reference allele of the PAI-2 polymorphism (hazard ratio 0.41 per allele, 95% CI 0.20-0.84, p=0.014) along with continued significant risk associations for the p22phox and thrombospondin-4 polymorphisms. Additionally, further analysis revealed interaction of the LRP-1 and PAI-2 polymorphisms in generating differential risk that was illustrated using Kaplan-Meier survival analysis. We conclude from the study that fibrinolysis likely plays a role in establishing recurrent coronary risk in postinfarction patients with concurrently high levels of HDL-C and CRP as manifested by differential effects on risk by polymorphisms of several genes linked to key actions involved in the fibrinolytic process.

Reactive Oxygen Species, SUMOylation, and Endothelial Inflammation.

Although the exact mechanism through which NADPH oxidases (Nox's) generate reactive oxygen species (ROS) is still not completely understood, it is widely considered that ROS accumulation is the cause of oxidative stress in endothelial cells. Increasing pieces of evidence strongly indicate the role for ROS in endothelial inflammation and dysfunction and subsequent development of atherosclerotic plaques, which are causes of various pathological cardiac events. An overview for a causative relationship between ROS and endothelial inflammation will be provided in this review. Particularly, a crucial role for specific protein SUMOylation in endothelial inflammation will be presented. Given that SUMOylation of specific proteins leads to increased endothelial inflammation, targeting specific SUMOylated proteins may be an elegant, effective strategy to control inflammation. In addition, the involvement of ROS production in increasing the risk of recurrent coronary events in a sub-group of non-diabetic, post-infarction patients with elevated levels of HDL-cholesterol will be presented with the emphasis that elevated HDL-cholesterol under certain inflammatory conditions can lead to increased incidence of cardiovascular events.

Apolipoprotein A-II influences apolipoprotein E-linked cardiovascular disease risk in women with high levels of HDL cholesterol and C-reactive protein.

BACKGROUND: In a previous report by our group, high levels of apolipoprotein E (apoE) were demonstrated to be associated with risk of incident cardiovascular disease in women with high levels of C-reactive protein (CRP) in the setting of both low (designated as HR1 subjects) and high (designated as HR2 subjects) levels of high-density lipoprotein cholesterol (HDL-C). To assess whether apolipoprotein A-II (apoA-II) plays a role in apoE-associated risk in the two female groups. METHODOLOGY/PRINCIPAL: Outcome event mapping, a graphical data exploratory tool; Cox proportional hazards multivariable regression; and curve-fitting modeling were used to examine apoA-II influence on apoE-associated risk focusing on HDL particles with apolipoprotein A-I (apoA-I) without apoA-II (LpA-I) and HDL particles with both apoA-I and apoA-II (LpA-I:A-II). Results of outcome mappings as a function of apoE levels and the ratio of apoA-II to apoA-I revealed within each of the two populations, a high-risk subgroup characterized in each situation by high levels of apoE and additionally: in HR1, by a low value of the apoA-II/apoA-I ratio; and in HR2, by a moderate value of the apoA-II/apoA-I ratio. Furthermore, derived estimates of LpA-I and LpA-I:A-II levels revealed for high-risk versus remaining subjects: in HR1, higher levels of LpA-I and lower levels of LpA-I:A-II; and in HR2 the reverse, lower levels of LpA-I and higher levels of LpA-I:A-II. Results of multivariable risk modeling as a function of LpA-I and LpA-I:A-II (dichotomized as highest quartile versus combined three lower quartiles) revealed association of risk only for high levels of LpA-I:A-II in the HR2 subgroup (hazard ratio 5.31, 95% CI 1.12-25.17, p = 0.036). Furthermore, high LpA-I:A-II levels interacted with high apoE levels in establishing subgroup risk. CONCLUSIONS/SIGNIFICANCE: We conclude that apoA-II plays a significant role in apoE-associated risk of incident CVD in women with high levels of HDL-C and CRP.

Apolipoprotein E predicts incident cardiovascular disease risk in women but not in men with concurrently high levels of high-density lipoprotein cholesterol and C-reactive protein.

Although there is great interest in the notion that dysfunctional transformation of high-density lipoprotein (HDL) facilitates development of atherosclerosis and cardiovascular disease (CVD), few studies in human populations directly address this issue. As apolipoprotein E (apoE) is a constituent of HDL thought to be important for HDL antiatherogenic function, we sought to assess the role of apoE in CVD risk in subjects likely to display dysfunctional transformation of HDL. Association of apoE levels with incident CVD risk was investigated using Cox multivariable proportional hazards modeling. Analyses were performed in subgroups of women and men likely to display dysfunctional transformation of HDL deriving from previous subgroup identification based upon defining characteristics of concurrently high levels of HDL cholesterol and systemic inflammation as reflected by high C-reactive protein levels. Results revealed apoE levels (dichotomized as highest quartile vs combined 3 lowest quartiles) as predicting subgroup risk in women (hazard ratio, 4.52; 95% confidence interval, 1.07-19.12; P = .040) but not in men. Further sex differences were manifested in terms of the relationship of apoE levels with age. Analysis revealed positive correlation of apoE levels with age in women (r = 0.47, P < .0001) but not in men (r = 0.04, P = .43). Apolipoprotein E levels predict incident CVD risk in women with high levels of HDL cholesterol and C-reactive protein but not in men. Future studies should be oriented toward investigations of apoE as related to multiplicity of HDL functionality and toward assessment of potential roles for apoE in dysfunctional transformation of HDL.

Thrombospondin-4 polymorphism (A387P) predicts cardiovascular risk in postinfarction patients with high HDL cholesterol and C-reactive protein levels.

Few studies are available in human populations investigating involvement of vascular inflammation and oxidative stress-related dysfunctional transformation of high-density lipoprotein (HDL) in establishing cardiovascular disease (CVD) risk. To this end, the current work investigated a subgroup of post-infarction patients at high-risk for recurrent events defined by high levels of HDL cholesterol (HDL-C) and concurrently high levels of C-reactive protein (CRP). Thrombospondin-4 (TSP-4), a matricellular protein of vessel walls associated with inflammation, was investigated in terms of CVD risk using multivariable modelling with a well-characterised functional genetic polymorphism of THBS4 (A387P, rs1866389) along with previously demonstrated risk-related functional genetic polymorphisms of CYBA (C242T, rs4673) and CETP (TaqIB, rs708272), and a set of blood markers. Results revealed risk-association for the gain-of-function P-allele of the THBS4 polymorphism (hazard ratio 2.00, 95% confidence interval 1.10-3.65, p=0.024). Additionally, von Willebrand factor was associated with D-dimer levels in the higher-risk P allele patients suggestive of a connection between endothelial dysfunction and thrombogenesis. In conclusion, TSP-4, a matricellular protein involved in regulating vascular inflammation, plays a role in establishing recurrent coronary risk in post-infarction patients with high levels of HDL-C and CRP. Further studies should focus on additional effects of vascular inflammatory processes on anti-atherogenic functionality of HDL particles.

Glycerol as a reference material for fecal fat quantitation using low-resolution time domain ¹H NMR spectroscopy.

OBJECTIVES: To assess glycerol as reference material for low-resolution time-domain (1)H NMR analysis of fecal fat. DESIGN AND METHODS: NMR analysis of fecal fat in stool samples with added glycerol was used to assess linearity, recovery, and relationship with NMR lipid signal. RESULTS: The study revealed for added glycerol excellent linearity (r=0.9998), recovery (101-104%), and linear relationship with simulated fecal fat content. CONCLUSIONS: Glycerol is an effective reference material for NMR fecal fat analysis.