Association between dietary macronutrient composition and plasma one-carbon metabolites and B-vitamin cofactors in patients with stable angina pectoris.

Elevated plasma concentrations of several one-carbon metabolites are associated with increased CVD risk. Both diet-induced regulation and dietary content of one-carbon metabolites can influence circulating concentrations of these markers. We cross-sectionally analysed 1928 patients with suspected stable angina pectoris (geometric mean age 61), representing elevated CVD risk, to assess associations between dietary macronutrient composition (FFQ) and plasma one-carbon metabolites and related B-vitamin status markers (GC-MS/MS, LC-MS/MS or microbiological assay). Diet-metabolite associations were modelled on the continuous scale, adjusted for age, sex, BMI, smoking, alcohol and total energy intake. Average (geometric mean (95 % prediction interval)) intake was forty-nine (38, 63) energy percent (E%) from carbohydrate, thirty-one (22, 45) E% from fat and seventeen (12, 22) E% from protein. The strongest associations were seen for higher protein intake, i.e. with higher plasma pyridoxal 5'-phosphate (PLP) (% change (95 % CI) 3·1 (2·1, 4·1)), cobalamin (2·9 (2·1, 3·7)), riboflavin (2·4 (1·1, 3·7)) and folate (2·1 (1·2, 3·1)) and lower total homocysteine (tHcy) (-1·4 (-1·9, -0·9)) and methylmalonic acid (MMA) (-1·4 (-2·0, -0·8)). Substitution analyses replacing MUFA or PUFA with SFA demonstrated higher plasma concentrations of riboflavin (5·0 (0·9, 9·3) and 3·3 (1·1, 5·6)), tHcy (2·3 (0·7, 3·8) and 1·3 (0·5, 2·2)) and MMA (2·0 (0·2, 3·9) and 1·7 (0·7, 2·7)) and lower PLP (-2·5 (-5·3, 0·3) and -2·7 (-4·2, -1·2)). In conclusion, a higher protein intake and replacing saturated with MUFA and PUFA were associated with a more favourable metabolic phenotype regarding metabolites associated with CVD risk.

B-vitamin Treatment Modifies the Mortality Risk Associated with Calcium Channel Blockers in Patients with Suspected Stable Angina Pectoris: A Prospective Cohort Study.

BACKGROUND: Calcium channel blockers (CCBs) are used for the treatment of cardiovascular disease (CVD), including angina pectoris, and hypertension; however, the effect on survival remains uncertain. CCBs impair fibrinolysis and have been linked to elevated plasma homocysteine (Hcy), a CVD risk marker. OBJECTIVE: We explored the association between CCB use and mortality in a large prospective cohort of patients with suspected stable angina pectoris (SAP), and potential effect modifications by Hcy-lowering B-vitamin treatment (folic acid, B12, and/or B6) as 61.8% of the patients participated in a randomized placebo-controlled B-vitamin intervention trial. METHODS: Patient baseline continuous characteristics according to CCB treatment were tested by linear regression. Hazard ratios (HRs) for mortality associated with CCB treatment, also according to B-vitamin intervention, were examined using Cox regression analysis. The multivariable model included CVD risk factors, medical histories, and the use of CVD medications. RESULTS: A total of 3991 patients (71.5 % men) were included, of whom 907 were prescribed CCBs at discharge. During 10.3 years of median follow-up, 20.6% died and 8.9% from cardiovascular- and 11.7% from non-cardiovascular causes. Patients treated with CCBs had higher plasma Hcy, fibrinogen levels, and erythrocyte sedimentation rate (all P<0.001). Furthermore, CCB use was positively associated with mortality, also after multivariable adjustments (HRs [95% CIs]: 1.34 [1.15,1.57], 1.35 [1.08,1.70], and 1.33 [1.09,1.64] for total, CVD, and non-CVD death, respectively). Numerically stronger associations were observed among patients not treated with B-vitamins (HR [95% CI]: 1.54 [1.25, 1.88], 1.69 [1.25, 2.30], and 1.41 [1.06, 1.86] for total, CVD deaths, and non-CVD deaths, respectively), whereas no association was seen in patients treated with B-vitamins (HR [95% CI]: 1.15 [0.91, 1.46], 1.09 [0.76, 1.57], and 1.20 [0.88, 1.65]). CONCLUSIONS: In patients with suspected SAP, CCB treatment was associated with increased mortality risk primarily among patients not treated with B-vitamins.

Plasma methylmalonic acid predicts risk of acute myocardial infarction and mortality in patients with coronary heart disease: A prospective 2-cohort study.

BACKGROUND: Elevated plasma methylmalonic acid (MMA) is reported in patients with established coronary heart disease (CHD) and is considered a marker of vitamin B12 deficiency. Moreover, MMA-dependent reactions have been linked to alterations in mitochondrial energy metabolism and oxidative stress, key features in the pathophysiology of cardiovascular diseases (CVDs). OBJECTIVES: We examined whether plasma MMA prospectively predicted the long-term risk of acute myocardial infarction (AMI) and mortality. METHODS AND RESULTS: Using Cox modeling, we estimated hazard ratios (HRs) for endpoints according to per 1-SD increment of log-transformed plasma MMA in two independent populations: the Western Norway Coronary Angiography Cohort (WECAC) (patients evaluated for CHD; n = 4137) and the Norwegian Vitamin Trial (NORVIT) (patients hospitalized with AMI; n = 3525). In WECAC and NORVIT, 12.8% and 18.0% experienced an AMI, whereas 21.8% and 19.9% died, of whom 45.5% and 60.3% from CVD-related causes during follow-up (range 3-11 years), respectively. In WECAC, age- and gender-adjusted HRs (95% confidence interval) were 1.18 (1.09-1.28), 1.25 (1.18-1.33), and 1.28 (1.17-1.40) for future AMI, total mortality, and CVD mortality, respectively. Corresponding risk estimates were 1.19 (1.10-1.28), 1.22 (1.14-1.31), and 1.30 (1.19-1.42) in NORVIT. These estimates were only slightly attenuated after multivariable adjustments. Across both cohorts, the MMA-risk association was stronger in older adults, women, and non-smokers. CONCLUSIONS: Elevated MMA was associated with an increased risk of AMI and mortality in patients with suspected or verified CHD.

Physical activity and risk of all-cause mortality in patients with stable angina pectoris: Effect modification by ß-blocker treatment.

Background: Physical activity (PA) influences sympathetic stimulation, platelet activation as well as vascular function, and has been associated with improved health outcomes in patients with coronary heart disease. ß-blocker therapy reduces sympathetic activity and improves platelet and endothelial function. We investigated if ß-blocker treatment modifies the association of self-reported PA with the risk of all-cause mortality. Methods: A total of 2284 patients undergoing elective coronary angiography for suspected stable angina pectoris (SAP) were studied. Using Cox modeling, we examined associations between PA (categorized as 'sedentary/inactive', 'low', 'moderate', and 'high') and all-cause mortality according to ß-blocker therapy. Results: During a median follow-up of 10.3 years, 390 patients (17.1%) died. Higher PA was generally associated with a more favorable cardiovascular risk profile. Compared to the patients who were sedentary or inactive, the age and sex adjusted HRs (95% CI) for all-cause mortality were 0.89 (0.66-1.20), 0.73 (0.57-0.95) and 0.72 (0.55-0.95) in the low, moderate and high PA group, respectively. However, and notably, these risk estimates were 0.85 (0.60-1.20), 0.65 (0.47-0.89) and 0.58 (0.41-0.81) in ß-blocker treated subjects vs. 1.00 (0.57-1.78), 0.96 (0.61-1.52) and 1.20 (0.74-1.95) in non-treated groups (P interaction = 0.018). The results were essentially similar in the multivariable adjusted models. Conclusions: In patients with suspected SAP, increased PA was associated with reduced mortality risk primarily in patients treated with ß-blockers.

Circulating trimethylamine N-oxide levels do not predict 10-year survival in patients with or without coronary heart disease.

BACKGROUND: Trimethylamine N-oxide (TMAO) is an amine oxide generated by gut microbial metabolism. TMAO may contribute to atherothrombosis and systemic inflammation. However, the prognostic value of circulating TMAO for risk stratification is uncertain. METHODS: We assessed prospective relationships of plasma TMAO with long-term risk of all-cause, cardiovascular (CV), and non-CV mortality in the Western Norway Coronary Angiography Cohort (WECAC; 4132 patients with suspected coronary artery disease) and the Hordaland Health Study (HUSK; 6393 community-based subjects). Risk associations were examined using Cox regression analyses. RESULTS: Mean follow-up was 9.8 and 10.5 years in WECAC and HUSK, respectively. Following adjustments for established CV risk factors and indices of renal function in WECAC, the hazard ratios (HRs) (95% confidence intervals [CIs]) per one standard deviation increase in log-transformed plasma TMAO were 1.04 (0.97-1.12), 1.06 (0.95-1.18), and 1.03 (0.93-1.13) for all-cause, CV, and non-CV mortality, respectively. Essentially similar results were obtained in patients with angiographically significant coronary artery disease and patients with reduced left ventricular ejection fraction. Corresponding HRs (95% CIs) in the HUSK cohort were 1.03 (0.96-1.10), 1.01 (0.89-1.13), and 1.03 (0.95-1.12) for all-cause-, CV, and non-CV mortality, respectively. CONCLUSIONS: Circulating TMAO did not predict long-term all-cause, CV, or non-CV mortality in patients with coronary heart disease or in community-based adults. This large study does not support a role of TMAO for patient risk stratification in primary or secondary prevention.

ß-blocker use and risk of all-cause mortality in patients with coronary heart disease: effect modification by serum vitamin A.

AIMS: Blockade of ß-adrenoceptors reduces sympathetic nervous system activity and improves survival in patients with heart failure with reduced left ventricular ejection fraction (HFrEF); however, any improvement in longevity among patients with coronary heart disease (CHD) but without HFrEF remains uncertain. Vitamin A has been linked to the activation of tyrosine hydroxylase, the rate-limiting enzyme in the catecholamine synthesis pathway. We investigated if vitamin A status modified the association of ß-blocker use with the risk of all-cause mortality. METHODS AND RESULTS: A total of 4118 patients undergoing elective coronary angiography for suspected stable angina pectoris, of whom the majority had normal left ventricular ejection fraction (LVEF) were studied. Hazard ratios (HRs) of all-cause mortality comparing treatment vs. non-treatment of ß-blockers according to the tertiles of serum vitamin A were explored in Cox proportional hazards regression models. During a median follow-up of 10.3 years, 897 patients (21.8%) died. The overall LVEF was 65% and 283 (6.9%) had anamnestic HF. After multivariable adjustments for traditional risk factors, medical history, and drug therapies of cardiovascular disease, ß-blocker treatment was inversely associated with the risk of all-cause mortality [HR : 0.84; 95% CI (confidence interval), 0.72-0.97]. However, the inverse association was generally stronger among patients in the upper serum vitamin A tertile (HR :0.66; 95% CI, 0.50-0.86; Pinteraction = 0.012), which remained present after excluding patients with LVEF < 40%. CONCLUSION: In patients with suspected CHD, ß-blocker treatment was associated with improved survival primarily among patients with high serum vitamin A levels.

Primary cardiovascular risk prediction by LDL-cholesterol in Caucasian middle-aged and older adults: a joint analysis of three cohorts.

AIMS: Low-density lipoprotein cholesterol (LDL-C) is an established causal driver of atherosclerotic cardiovascular disease (ASCVD), but its performance and age-dependency as a biomarker for incident events and mortality arising from ASCVD is less clear. The aim was to determine the value of LDL-C as a susceptibility/risk biomarker for incident coronary heart disease (CHD), ASCVD, and stroke events and deaths, for the age groups <50 and ≥50 years. METHODS AND RESULTS: The performance of LDL-C was evaluated in three cohorts, FINRISK 2002 (n = 7709), HUSK (n = 5431), and ESTHER (n = 4559), by Cox proportional hazards models, C-statistics, and net reclassification index calculations. Additionally, the hazard ratios (HRs) for the three cohorts were pooled by meta-analysis. The most consistent association was observed for CHD [95% confidence interval (CI) for HRs per standard deviation ranging from 0.99 to 1.37], whereas the results were more modest for ASCVD (0.96-1.18) due to lack of association with stroke (0.77-1.24). The association and discriminatory value of LDL-C with all endpoints in FINRISK 2002 and HUSK were attenuated in subjects 50 years and older [HRs (95% CI) obtained from meta-analysis 1.11 (1.04-1.18) for CHD, 1.15 (1.02-1.29) for CHD death, 1.02 (0.98-1.06) for ASCVD, 1.12 (1.02-1.23) for ASCVD death, and 0.97 (0.89-1.05) for stroke]. CONCLUSION: In middle-aged and older adults, associations between LDL-C and all the studied cardiovascular endpoints were relatively weak, while LDL-C showed stronger association with rare events of pre-mature CHD or ASCVD death among middle-aged adults. The predictive performance of LDL-C also depends on the studied cardiovascular endpoint.

Trimethyllysine predicts all-cause and cardiovascular mortality in community-dwelling adults and patients with coronary heart disease.

Aims: Trimethyllysine (TML) is involved in carnitine synthesis, serves as a precursor of trimethylamine N-oxide (TMAO) and is associated with cardiovascular events in patients with established coronary heart disease (CHD). We prospectively examined circulating TML as a predictor of all-cause and cardiovascular mortality in community-dwelling adults and patients with CHD. Methods and results: By Cox regression modelling, risk associations were examined in 6393 subjects in the community-based Hordaland Health Study (HUSK). A replication study was conducted among 4117 patients with suspected stable angina pectoris in the Western Norway Coronary Angiography Cohort (WECAC). During a mean follow-up of 10.5 years in the HUSK-cohort, 884 (13.8%) subjects died, of whom 287 from cardiovascular causes. After multivariable adjustments for traditional cardiovascular risk factors, the hazard ratio (HR) [95% confidence interval (95% CI)] for all-cause mortality comparing the 4th vs. 1st TML-quartile was 1.66 (1.31-2.10, P < 0.001). Particularly strong associations were observed for cardiovascular mortality [HR (95% CI) 2.04 (1.32-3.15, P = 0.001)]. Corresponding risk-estimates in the WECAC (mean follow-up of 9.8 years) were 1.35 [1.10-1.66, P = 0.004] for all-cause and 1.45 [1.06-1.98, P = 0.02] for cardiovascular mortality. Significant correlations between plasma TML and TMAO were observed in both cohorts (rs ≥ 0.42, P < 0.001); however, additional adjustments for TMAO did not materially influence the risk associations, and no effect modification by TMAO was found. Conclusions: Elevated TML-levels were associated with increased risk of all-cause and cardiovascular mortality both in subjects with and without established CHD.

Lipid parameters and vitamin A modify cardiovascular risk prediction by plasma neopterin.

OBJECTIVES: Oxidised cholesterol metabolites are linked to increased production of the active vitamin A (Vit-A) form and monocyte/macrophage activation, which may be reflected by neopterin, a marker of both interferon-γ-mediated immune activation and coronary artery disease risk. We examined the influence of serum lipid parameters and Vit-A on the risk association between neopterin and incident acute myocardial infarction (AMI). METHODS: We included 4130 patients with suspected stable angina pectoris (SAP), of whom 80% received lipid-lowering treatment with statins. Risk associations between plasma neopterin and AMI are given as HRs per SD increase in log-transformed neopterin. RESULTS: During a median follow-up of 7.5 years, 530 (12.8%) patients experienced an AMI. In age-adjusted and sex-adjusted analysis, plasma neopterin was positively associated with incident AMI (HR (95% CI) per SD: 1.26 (1.17 to 1.35)). However, the estimates were most pronounced in patients with serum low-density lipoprotein cholesterol (LDL-C) or apolipoprotein (apo) B100 below-median (HR (95% CI) per SD: 1.35 (1.24 to 1.48) and 1.42 (1.27 to 1.58), respectively; both pinteraction ≤0.03). We also observed a particularly strong risk association in those with above-median Vit-A (HR (95% CI) per SD: 1.32 (1.21 to 1.44); pinteraction=0.03). The estimates were slightly modified after multivariable adjustment. CONCLUSIONS: In patients with suspected SAP, the majority of whom receiving statin therapy, high plasma neopterin was associated with increased risk of AMI particularly among those with low LDL-C and apoB100 or high Vit-A levels. The particularly strong relationship of plasma neopterin with residual cardiovascular risk in patients with low lipid levels should be further investigated.

Transsulfuration metabolites and the association with incident atrial fibrillation - An observational cohort study among Norwegian patients with stable angina pectoris.

BACKGROUND/AIM: Plasma total homocysteine (tHcy) is elevated in patients with persistent vs. paroxysmal atrial fibrillation (AF), and has been related to increased risk of new-onset AF. Homocysteine is degraded to cystathionine (Cysta) and cysteine (Cys). All three metabolites have been linked to potential proarrhythmic traits such as inflammation and atrial fibrosis. We evaluated the prospective association between these metabolites and new-onset AF among patients with suspected stable angina pectoris. METHODS: Information regarding AF was obtained by linking patient data to national health registries. Risk associations were explored by Cox regression and potential improvements in risk reclassification were calculated by the continuous net reclassification index (NRI > 0). RESULTS: At baseline, 3535 patients without any prior history of AF were included. During median follow-up of 7.4 years, 392 patients (10.2%) were registered with incident AF. Higher plasma tHcy and tCys were associated with increased risk of incident AF [age and gender adjusted HRs (95% CI) per 1 log transformed SD 1.23 (1.12-1.35) and 1.23 (1.11-1.38)]; multivariate adjustment yielded similar results. Plasma tHcy and tCys also improved reclassification of patients (NRI > 0 (95% CI)) for tHcy 0.118 (0.02-0.22) and tCys 0.107 (0.002-0.21). No association was seen between plasma Cysta and incident AF. CONCLUSION: Plasma tHcy and tCys, but not Cysta, were associated with, and improved risk classification of, new-onset AF among patients with stable angina pectoris. Our results motivate further studies to explore the relationship between homocysteine metabolism and cardiac arrhythmias.

Development and validation of a ceramide- and phospholipid-based cardiovascular risk estimation score for coronary artery disease patients.

AIMS: Distinct ceramide lipids have been shown to predict the risk for cardiovascular disease (CVD) events, especially cardiovascular death. As phospholipids have also been linked with CVD risk, we investigated whether the combination of ceramides with phosphatidylcholines (PCs) would be synergistic in the prediction of CVD events in patients with atherosclerotic coronary heart disease in three independent cohort studies. METHODS AND RESULTS: Ceramides and PCs were analysed using liquid chromatography-mass spectrometry (LC-MS) in three studies: WECAC (The Western Norway Coronary Angiography Cohort) (N = 3789), LIPID (Long-Term Intervention with Pravastatin in Ischaemic Disease) trial (N = 5991), and KAROLA (Langzeiterfolge der KARdiOLogischen Anschlussheilbehandlung) (N = 1023). A simple risk score, based on the ceramides and PCs showing the best prognostic features, was developed in the WECAC study and validated in the two other cohorts. This score was highly significant in predicting CVD mortality [multiadjusted hazard ratios (HRs; 95% confidence interval) per standard deviation were 1.44 (1.28-1.63) in WECAC, 1.47 (1.34-1.61) in the LIPID trial, and 1.69 (1.31-2.17) in KAROLA]. In addition, a combination of the risk score with high-sensitivity troponin T increased the HRs to 1.63 (1.44-1.85) and 2.04 (1.57-2.64) in WECAC and KAROLA cohorts, respectively. The C-statistics in WECAC for the risk score combined with sex and age was 0.76 for CVD death. The ceramide-phospholipid risk score showed comparable and synergistic predictive performance with previously published CVD risk models for secondary prevention. CONCLUSION: A simple ceramide- and phospholipid-based risk score can efficiently predict residual CVD event risk in patients with coronary artery disease.

Creatinine, total cysteine and uric acid are associated with serum retinol in patients with cardiovascular disease.

PURPOSE: We hypothesized that biomarkers and dietary factors related to cardiovascular disease risk were associated with serum retinol and evaluated these potential associations in patients with suspected coronary artery disease (CAD). METHODS: We used cross-sectional data from 4116 patients hospitalised for suspected CAD. Dietary data were obtained from a subgroup of 1962 patients using a food frequency questionnaire. Potential biomarkers and dietary factors were explored using linear regression modelling adjusted for age and sex. Regression coefficients and corresponding confidence intervals (CI) are given as  % change in serum retinol per unit change in the predictors. Analyses were performed in the total population and in strata of serum retinol tertiles. RESULTS: In age- and sex-adjusted models, serum creatinine (standardized ß: 0.38, 95% CI [0.35, 0.42]), plasma total cysteine (0.26, [0.23, 0.29]), serum uric acid (0.30, [0.26, 0.33]) and plasma neopterin (0.22, [0.18, 0.25]) were positively associated, whereas plasma serine (- 0.15, [- 0.18, - 0.12]) and serum C-reactive protein (- 0.15, [- 0.18, - 0.12]) were inversely associated with serum retinol. When we included the significant biomarkers in a multivariate model, the model explained 33% of the variability (R2 = 0.33) in serum retinol. The results were similar in the lower and upper tertiles of serum retinol. Weak or no associations were observed for dietary factors. CONCLUSIONS: In patients with suspected CAD, concentrations of creatinine, cysteine and uric acid were positively associated with serum retinol. Future studies should assess whether retinol concentrations are influenced by metabolic alterations in patients at risk of cardiovascular disease.

SGLT1 inhibition boon or bane for diabetes-associated cardiomyopathy.

Chronic hyperglycaemia is a peculiar feature of diabetes mellitus (DM). Sequential metabolic abnormalities accompanying glucotoxicity are some of its implications. Glucotoxicity most likely corresponds to the vascular intricacy and metabolic alterations, such as increased oxidation of free fatty acids and reduced glucose oxidation. More than half of those with diabetes also develop cardiac abnormalities due to unknown causes, posing a major threat to the currently available marketed preparations which are being used for treating these cardiac complications. Even though impairment in cardiac functioning is the principal cause of death in individuals with type 2 diabetes (T2D), reducing plasma glucose levels has little effect on cardiovascular disease (CVD) risk. In vitro and in vivo studies have demonstrated that inhibitors of sodium glucose transporter (SGLT) represent a putative therapeutic intervention for these pathological conditions. Several clinical trials have reported the efficacy of SGLT inhibitors as a novel and potent antidiabetic agent which along with its antihyperglycaemic activity possesses the potential of effectively treating its associated cardiac abnormalities. Thus, hereby, the present review highlights the role of SGLT inhibitors as a successful drug candidate for correcting the shifts in deregulation of cardiac energy substrate metabolism together with its role in treating diabetes-related cardiac perturbations.

Dietary choline is related to increased risk of acute myocardial infarction in patients with stable angina pectoris.

High plasma choline has been associated with the metabolic syndrome and risk of chronic diseases, including cardiovascular disease. However, dietary choline is not correlated with choline plasma concentrations, and there are few studies and contradictory evidence regarding dietary choline and cardiovascular events. In addition, a recommended dietary allowance for choline has not been established and remains a point of contention. This study assessed the association between dietary choline, including choline forms, and risk of incident acute myocardial infarction (AMI) in patients with suspected stable angina pectoris (SAP). In total 1981 patients (80% men, median age 62) from the Western Norway B Vitamin Intervention Trial were included in this analysis. Information on dietary choline was obtained using a 169-item food frequency questionnaire. The Cardiovascular Disease in Norway project provided data on AMI. Risk associations were estimated using Cox-regression analysis using energy-adjusted choline intake. Median (25th, 75th percentile) total energy-adjusted choline intake was 288 (255, 326) mg/d. During a median (25th, 75th percentile) follow-up of 7.5 (6.3, 8.8) years, 312 (15.7%) patients experienced at least one AMI. Increased intakes of energy-adjusted choline (HR [95% CI] per 50 mg increase 1.11 [1.03, 1.20]), phosphatidylcholine (HR per 50 mg increase 1.24 [1.08, 1.42]) and sphingomyelin (HR per 5 mg increase 1.16 [1.02, 1.31]) were associated with higher AMI risk. In conclusion, higher dietary intakes of total choline, phosphatidylcholine and sphingomyelin were associated with increased risk of AMI in patients with SAP. Future studies are necessary to explore underlying mechanisms for this observation.

Elevated plasma cystathionine is associated with increased risk of mortality among patients with suspected or established coronary heart disease.

BACKGROUND: Elevated circulating cystathionine levels are related to atherosclerotic cardiovascular disease, a leading cause of death globally. OBJECTIVE: We investigated whether plasma cystathionine was associated with mortality in patients with suspected or established coronary heart disease (CHD). METHODS: Data from 2 independent cohorts of patients with suspected stable angina pectoris (SAP) (3033 patients; median 10.7 y follow-up; 648 deaths) or acute myocardial infarction (AMI) (3670 patients; median 7.0 y follow-up; 758 deaths) were included. Hazard ratios with 95% CIs per SD increment of log-transformed cystathionine were calculated using Cox regression modeling. Endpoint data was obtained from a national health registry. RESULTS: Among patients with SAP, there was a positive association between plasma cystathionine and death (age- and sex-adjusted HRs [95% CI] per SD: 1.23 [1.14, 1.32], 1.29 [1.16, 1.44], and 1.17 [1.05, 1.29] for total, cardiovascular, and noncardiovascular mortality, respectively). Corresponding risk estimates were 1.28 (1.19, 1.37) for all-cause, 1.33 (1.22, 1.45) for cardiovascular, and 1.19 (1.06, 1.34) for noncardiovascular death among AMI patients. In both cohorts, estimates were slightly attenuated after multivariate adjustments for established CHD risk factors. Subgroup analyses showed that the relation between cystathionine and all-cause mortality in SAP patients was stronger among nonsmokers and those with lower plasma concentration of pyridoxal-5'-phosphate (P-interaction ≤ 0.01 for both). CONCLUSIONS: Elevated plasma cystathionine is associated with both cardiovascular and noncardiovascular mortality among patients with suspected or established CHD. The joint risk associations of high plasma cystathionine with lifestyle factors and impaired vitamin B-6 status on mortality need further investigation. This trial was registered at clinicaltrials.gov as NCT00354081 and NCT00266487.

Inhibition of protein kinase R protects against palmitic acid-induced inflammation, oxidative stress, and apoptosis through the JNK/NF-kB/NLRP3 pathway in cultured H9C2 cardiomyocytes.

BACKGROUND AND PURPOSE: Double-stranded RNA-dependent protein kinase (PKR) is a critical regulator of apoptosis, oxidative stress, and inflammation under hyperlipidemic and insulin resistance conditions. Saturated free fatty acids, such as palmitic acid (PA), are known inducers of apoptosis in numerous cell types. However, the underlying molecular mechanism is not fully understood. The aim of the present study was to examine the effect of PA on cultured rat H9C2 cardiac myocytes cells and to investigate the PKR mediated harmful effects of PA in vitro in cultured cardiomyocytes. EXPERIMENTAL APPROACH: PKR expression was determined by immunofluorescence and immunoblotting. Oxidative stress and apoptosis were determined by flow cytometry and assay kits. The expression of different gene markers of apoptosis, oxidative stress, and inflammation were measured by Western blot analysis and reverse transcription polymerase chain reaction. KEY RESULTS: PKR expression, reactive oxygen species levels as well as apoptosis were increased in PA-treated cultured H9C2 cardiomyocytes. The harmful effects of PA were attenuated by a selective PKR inhibitor, C16. Moreover, we observed that upregulation of c-Jun N-terminal kinase (JNK), nuclear factor-kB (NF-kB) and NACHT, LRR and PYD domains-containing protein 3 (NLRP3) pathways is associated with increased expression of interleukin 6 and tumor necrosis factor-α in PA-treated cardiomyocytes and attenuation by a selective PKR inhibitor. CONCLUSION AND IMPLICATIONS: Our study reports, for the first time, that PKR-mediated harmful effects of PA in cultured cardiomyocytes via activation of JNK, NF-kB, and NLRP3 pathways. Inhibition of PKR is one of the possible mechanistic approaches to inhibit inflammation, oxidative stress, and apoptosis in lipotoxicity-induced cardiomyocyte damage.

Plasma Cystathionine and Risk of Incident Stroke in Patients With Suspected Stable Angina Pectoris.

Background Cystathionine is an intermediate product in the transsulfuration pathway and formed during the B6-dependent conversion of methionine to cysteine. Elevated plasma cystathionine has been related to atherosclerosis, which is a major etiological factor for ischemic stroke. However, the role of cystathionine in stroke development is unknown. Therefore, we prospectively assessed the association of circulating levels of cystathionine with risk of total and ischemic stroke. Methods and Results Two-thousand thirty-six patients (64% men; median age, 62 years) undergoing coronary angiography for suspected stable angina pectoris were included. Stroke cases were identified by linkage to the CVDNOR (Cardiovascular Disease in Norway) project. Hazard ratios with confidence intervals (95% confidence interval) were estimated by using Cox-regression analyses. During 7.3 years of median follow-up, 124 (6.1%) incident strokes were ascertained, which comprised 100 cases of ischemic stroke. There was a positive association of plasma cystathionine with risk of total stroke and ischemic stroke. Comparing the fourth versus the first cystathionine quartiles, age- and sex-adjusted hazard ratios (95% confidence interval) were 2.11 (1.19-3.75) and 2.56 (1.31-4.99) for total and ischemic stroke, respectively. Additional adjustment for major stroke risk factors only slightly attenuated the associations, which tended to be stronger in patients without previous or existing atrial fibrillation at baseline (hazard ratio [95% confidence interval], 2.43 [1.27-4.65] and 2.88 [1.39-5.98] for total and ischemic stroke, respectively). Conclusions In patients with suspected stable angina pectoris, plasma cystathionine was independently related to increased risk of total stroke and, in particular, ischemic stroke. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 00354081.

Pharmacological evaluation of novel PKR inhibitor indirubin-3-hydrazone in-vitro in cardiac myocytes and in-vivo in wistar rats.

AIMS: Double stranded protein kinase R cellular response is associated with various stress signals such as nutrients, endoplasmic stress, cytokines and mechanical stress. Increased PKR activity has been observed under diabetic and cardiovascular disease conditions. Most of the currently available PKR inhibitors are non-specific and have other effects as well. Thus, the aim of the present study was to examine the effect of novel PKR inhibitor indirubin-3-hydrazone (IHZ) in cultured rat H9C2 cardiomyocytes and wistar rats. MATERIALS AND METHODS: PKR expression was determined by Q-PCR, immunofluorescence and immunoblotting. The expression of different gene markers for apoptosis was measured by RT-PCR. Apoptosis and oxidative stress were determined by flow cytometry. KEY FINDINGS: High glucose (HG) treated H9C2 cardiomyocytes and high fructose (HF) treated wistar rats developed a significant increase in PKR expression. A significant increase in apoptosis and generation of reactive oxygen species was also observed in HG treated H9C2 cells and HF treated rats. Reduced vacuole formation and prominent nuclei were also observed in high glucose treated cells. Cardiac hypertrophy and increased fibrosis were observed in HF treated rats. All these effects of HG and HF were attenuated by novel PKR inhibitor, indirubin-3-hydrazone. SIGNIFICANCE: Our results indicate IHZ as an effective inhibitor of PKR in vitro and in-vivo, thus it may prove very useful in blocking the multiple harmful effects of PKR.

The risk association of plasma total homocysteine with acute myocardial infarction is modified by serum vitamin A.

Background Plasma total homocysteine (tHcy) has been implicated in the development of cardiovascular disease, but the mechanisms remain unclear. Vitamin A (Vit-A) is involved in homocysteine metabolism and we therefore explored the potential interaction between plasma tHcy and serum Vit-A in relation to incident acute myocardial infarction. Methods Cox proportional hazards models were used to assess the prospective relationships between tHcy and acute myocardial infarction in 2205 patients from Western Norway undergoing elective coronary angiography for suspected stable angina pectoris. Results are reported as hazard ratio per standard deviation increase in log-transformed tHcy. An interaction term for tHcy × Vit-A was added to multivariate models including age, sex, smoking, apolipoprotein B fasting, statin and aspirin prescription and estimated glomerular filtration rate. Results Geometric mean (geometric standard deviation) age of the participants (64.3% men) was 62.3 (1.24) years. Plasma tHcy was higher among participants in the upper versus lower Vit-A tertile. During 7 (2.4) years of follow-up, 15.1% suffered an AMI. A significant association of plasma tHcy with AMI in the total study population was observed. When we stratified the population according to Vit-A tertiles, plasma tHcy was associated with acute myocardial infarction only in the upper Vit-A tertile (hazard ratio per SD: 1.25, 95% confidence interval: 1.04-1.53, pinteraction = 0.03). Conclusions The risk relationship between plasma tHcy and acute myocardial infarction was modified by serum concentrations of Vit-A in patients with suspected stable angina pectoris. This finding may clarify the relationship between tHcy and cardiovascular disease.

Increased plasma trimethylamine-N-oxide is associated with incident atrial fibrillation.

BACKGROUND: Plasma trimethylamine-N-oxide (TMAO) is associated with cardiovascular disease; however specific relationships with cardiac arrhythmias are unknown. We evaluated the association between plasma TMAO and incident atrial fibrillation (AF). METHODS: Risk associations were explored among 3797 patients with suspected stable angina in the Western Norway Coronary Angiography Cohort (WECAC) and verified in 3143 elderly participants in the community-based Hordaland Health Study (HUSK). Information on endpoints was obtained from nationwide registries. RESULTS: Median follow-up was 7.3 and 10.8 years in the WECAC and HUSK cohorts, respectively, and 412 (10.9%) and 484 (15.4%) subjects were registered with incident AF. The age and gender adjusted HRs were 1.16, 95% CI 1.05-1.28 and 1.10, 95% CI 1.004-1.19 per 1 SD increase in log-transformed plasma TMAO. Adjusting for hypertension, BMI, smoking, diabetes, or intake of total choline, a TMAO precursor, did not materially influence the risk associations. Among patients in WECAC, further extensive adjustment for other AF risk factors yielded similar results. Adding TMAO to traditional AF risk factors (age, gender, hypertension, BMI, smoking and diabetes) yielded a continuous net reclassification improvement of 0.108, 95% CI 0.015-0.202 and 0.139, 95% CI 0.042-0.235. CONCLUSIONS: Plasma TMAO was associated with and improved reclassification of incident AF in two independent Norwegian cohorts with long-term follow-up. The relationship was independent of traditional AF risk factors, as well as of dietary choline intake. Our findings motivate further studies to explore endogenous metabolic factors influencing the relationship between TMAO and cardiovascular disease.