Cardioprotective effect of the mitochondrial unfolded protein response during chronic pressure overload

Background The mitochondrial unfolded protein response (UPRmt) is activated when misfolded proteins accumulate within mitochondria and leads to increased expression of mitochondrial chaperones and proteases to maintain protein quality and mitochondrial function. Cardiac mitochondria are essential for contractile function and regulation of cell viability, while mitochondrial dysfunction characterizes heart failure. The role of the UPRmt in the heart is unclear. Objectives The purpose of this study was to: 1) identify conditions that activate the UPRmt in the heart; and 2) study the relationship among the UPRmt, mitochondrial function, and cardiac contractile function. Methods Cultured cardiac myocytes were subjected to different stresses in vitro. Mice were subjected to chronic pressure overload. Tissues and blood biomarkers were studied in patients with aortic stenosis. Results Diverse neurohumoral or mitochondrial stresses transiently induced the UPRmt in cultured cardiomyocytes. The UPRmt was also induced in the hearts of mice subjected to chronic hemodynamic overload. Boosting the UPRmt with nicotinamide riboside (which augments NAD+ pools) in cardiomyocytes in vitro or hearts in vivo significantly mitigated the reductions in mitochondrial oxygen consumption induced by these stresses. In mice subjected to pressure overload, nicotinamide riboside reduced cardiomyocyte death and contractile dysfunction. Myocardial tissue from patients with aortic stenosis also showed evidence of UPRmt activation, which correlated with reduced tissue cardiomyocyte death and fibrosis and lower plasma levels of biomarkers of cardiac damage (high-sensitivity troponin T) and dysfunction (N-terminal pro–B-type natriuretic peptide). Conclusions These results identify the induction of the UPRmt in the mammalian (including human) heart exposed to pathological stresses. Enhancement of the UPRmt ameliorates mitochondrial and contractile dysfunction, suggesting that it may serve an important protective role in the stressed heart

Heme iron intake and risk of new-onset diabetes in a Mediterranean population at high risk of cardiovascular disease: an observational cohort analysis

BACKGROUND: Several epidemiological studies have observed an increased risk of type 2 diabetes mellitus (T2DM) among subjects with a higher consumption of red and processed meat. Heme iron intake has been directly associated with a higher risk of T2DM in healthy adult Chinese and U.S populations. The objective of the present study was to evaluate the association between heme iron intake and the incidence of T2DM in a Mediterranean population at high cardiovascular risk. METHODS: We assessed a subset of participants in the PREDIMED trial as an observational cohort, followed up for a maximum of eight years. We initially included 1073 non-diabetic subjects (57.1% women) aged 67.3 ± 6.0 years, at high cardiovascular risk. Diet was assessed at the study baseline using a validated, semi-quantitative food frequency questionnaire. RESULTS: During the follow-up period 131 diabetics were newly diagnosed. The risk of developing T2DM was assessed using baseline heme iron intake and proportional hazard models, first unadjusted, then adjusted for energy, and finally adjusted for dietary, anthropometric, socio-demographic and lifestyle variables. Significant direct associations with the incidence of T2DM were found for heme iron (Hazard Ratio [HR] 1.30, 95% confidence interval [CI], 1.02 to 1.66). Secondarily, we have also observed that coffee (HR:0.93, 95% CI, 0.89 to 0.98) and alcoholic beverages (HR: 1.02, 95% CI, 1.01 to 1.04) were also found to reduce and increase the risk of T2DM, respectively. CONCLUSION: High dietary intake of heme iron was associated with an increased risk of developing T2DM in a Mediterranean population at high cardiovascular risk. TRIAL REGISTRATION: Identifier: ISRCTN35739639

Polymorphism of the transcription factor 7-like 2 gene (TCF7L2) interacts with obesity on type-2 diabetes in the PREDIMED study emphasizing the heterogeneity of genetic variants in type-2 diabetes risk prediction: time for obesity-specific genetic risk scores

Nutrigenetic studies analyzing gene–diet interactions of the TCF7L2-rs7903146 C > T polymorphism on type-2 diabetes (T2D) have shown controversial results. A reason contributing to this may be the additional modulation by obesity. Moreover, TCF7L2-rs7903146 is one of the most influential variants in T2D-genetic risk scores (GRS). Therefore, to increase the predictive value (PV) of GRS it is necessary to first see whether the included polymorphisms have heterogeneous effects. We comprehensively investigated gene-obesity interactions between the TCF7L2-rs7903146 C > T polymorphism on T2D (prevalence and incidence) and analyzed other T2D-polymorphisms in a sub-sample. We studied 7018 PREDIMED participants at baseline and longitudinally (8.7 years maximum follow-up). Obesity significantly interacted with the TCF7L2-rs7903146 on T2D prevalence, associations being greater in non-obese subjects. Accordingly, we prospectively observed in non-T2D subjects (n = 3607) that its association with T2D incidence was stronger in non-obese (HR: 1.81; 95% CI: 1.13–2.92, p = 0.013 for TT versus CC) than in obese subjects (HR: 1.01; 95% CI: 0.61–1.66; p = 0.979; p-interaction = 0.048). Accordingly, TCF7L2-PV was higher in non-obese subjects. Additionally, we created obesity-specific GRS with ten T2D-polymorphisms and demonstrated for the first time their higher strata-specific PV. In conclusion, we provide strong evidence supporting the need for considering obesity when analyzing the TCF7L2 effects and propose the use of obesity-specific GRS for T2D

Lifestyles and risk factors associated with adherence to the Mediterranean diet: a baseline assessment of the PREDIMED trial

Background: The traditional Mediterranean dietary pattern (MedDiet) is associated with longevity and low rates of cardiovascular disease (CVD). However, there is little information on who is more likely to follow this food pattern. Aim: To evaluate how different factors are associated with lower MedDiet adherence in older Spanish subjects. Methods: We included 7305 participants (men aged 55-80 y, women 60-80 y) at high-risk of CVD recruited into the PREDIMED trial (ISRCTN35739639). Socioeconomic, anthropometric, lifestyle characteristics and CVD risk factors were recorded. A validated 14-item questionnaire was used to evaluate MedDiet adherence at baseline. Multivariate models were used to estimate odds ratios (OR) and 95% confidence intervals for lower adherence to the MedDiet (<9 points out of 14) and ascertain factors independently associated with it. Results: Former smoking (OR = 0.87; 95% CI, 0.78-0.98), physical activity (OR for the 3(rd) vs. the 1(st)tertile: 0.69; 0.62-0.78), and higher educational level (OR for university vs. less than primary school: 0.54; 0.38-0.77) were associated with higher MedDiet adherence. Conversely, having a larger waist-to-height ratio (OR for 0.1 units, 1.35; 1.22-1.49), being diabetic (OR = 1.13; 1.03-1.24), being single (OR = 1.27; 1.01-1.61) or divorced or separated (OR = 1.44; 1.09-1.89), and current smoking (OR = 1.28; 1.11-1.47) were associated with lower adherence. Conclusions: Participants with little education, a larger waist-to-height ratio, or diabetes and those who were less physically active, single, divorced or separated, or smokers were less likely to adhere to the MedDiet, an ideal model for food choices. Stronger efforts of health promotion are needed in these groups to foster adoption of the MedDiet

Dietary diversity and Depression: Cross-sectional and longitudinal analyses in Spanish adult population with Metabolic Syndrome. Findings from PREDIMED-PLUS Trial.

Objective: To examine the cross-sectional and longitudinal (2-year follow-up) associations between Dietary Diversity (DD) and depressive symptoms. Design: An energy-adjusted Dietary Diversity Score (DDS) was assessed using a validated food-frequency questionnaire and was categorized into quartiles (Q). The variety in each food group was classified into 4 categories of diversity (C). Depressive symptoms were assessed with Beck Depression Inventory-II (Beck II) questionnaire and depression cases defined as physician-diagnosed or Beck II>=18. Linear and logistic regression models were used. Setting: Spanish older adults with Metabolic Syndrome. Participants: A total of 6625 adults aged (55-75 years) from the PREDIMED-Plus study with overweight or obesity and MetS. Results: Total DDS was inversely and statistically significantly associated with depression in the cross-sectional analysis conducted; Odds Ratio (OR) Q4 vs Q1= 0.76 (95% confidence interval (CI): 0.64, 0.90). This was driven by high diversity compared to low diversity (C3 vs. C1) of vegetables [OR (95%CI) = 0.75 (0.57, 0.93)], cereals [OR (95%CI) = 0.72 (0.56-0.94)] and proteins [OR (95%CI) = 0.27 (0.11, 0.62)]. In the longitudinal analysis, there was no significant association between the baseline DDS and changes in depressive symptoms after 2 y- of follow-up, except for DD in vegetables C4 vs C1= [β (95%CI) = 0.70 (0.05, 1.35)]. Conclusions: According to our results, DD is associated with the presence of depressive symptoms but eating more diverse does not seem to reduce the risk of future depression. Additional longitudinal studies (with longer follow-up period) are needed to confirm these findings

Heme iron intake and risk of new-onset diabetes in a Mediterranean population at high risk of cardiovascular disease: an observational cohort analysis

BACKGROUND: Several epidemiological studies have observed an increased risk of type 2 diabetes mellitus (T2DM) among subjects with a higher consumption of red and processed meat. Heme iron intake has been directly associated with a higher risk of T2DM in healthy adult Chinese and U.S populations. The objective of the present study was to evaluate the association between heme iron intake and the incidence of T2DM in a Mediterranean population at high cardiovascular risk. METHODS: We assessed a subset of participants in the PREDIMED trial as an observational cohort, followed up for a maximum of eight years. We initially included 1073 non-diabetic subjects (57.1% women) aged 67.3 ± 6.0 years, at high cardiovascular risk. Diet was assessed at the study baseline using a validated, semi-quantitative food frequency questionnaire. RESULTS: During the follow-up period 131 diabetics were newly diagnosed. The risk of developing T2DM was assessed using baseline heme iron intake and proportional hazard models, first unadjusted, then adjusted for energy, and finally adjusted for dietary, anthropometric, socio-demographic and lifestyle variables. Significant direct associations with the incidence of T2DM were found for heme iron (Hazard Ratio [HR] 1.30, 95% confidence interval [CI], 1.02 to 1.66). Secondarily, we have also observed that coffee (HR:0.93, 95% CI, 0.89 to 0.98) and alcoholic beverages (HR: 1.02, 95% CI, 1.01 to 1.04) were also found to reduce and increase the risk of T2DM, respectively. CONCLUSION: High dietary intake of heme iron was associated with an increased risk of developing T2DM in a Mediterranean population at high cardiovascular risk. TRIAL REGISTRATION: Identifier: ISRCTN35739639

Macronutrient intake and metabolic syndrome in subjects at high cardiovascular risk

The effect of macronutrient intake on the metabolic syndrome (MS) is still controversial. Our aim in this study was to assess the relationships between macronutrient intake and the risk of developing the MS in subjects at high cardiovascular risk. METHODS: In this cross-sectional study, 967 high-risk men and women (55-80 years) were assessed according to the MS criteria defined by the National Cholesterol Education Program Adult Treatment Panel III (ATP3) and those established by the International Diabetes Federation (IDF). A 137-item validated food frequency questionnaire was used. Odds ratios (OR) for macronutrient intake and MS were calculated and adjustments were made for potential confounders. RESULTS: When applying the ATP3 criteria, an inverse association was found for fiber and polyunsaturated fatty acid (PUFAs) intake, with ORs of 0.55 (95% CI: 0.35-0.86) and 0.60 (95% CI: 0.39-0.94), respectively, for the 5th versus the 1st quintile. Using the IDF criteria, an inverse association between fiber intake and the MS was obtained whereas a direct association was found between carbohydrate intake and the MS: OR = 1.71 (95% CI: 1.05-2.79) for the highest versus the lowest quintile. CONCLUSIONS: A diet rich in fiber and PUFAs is correlated with a reduced risk of MS in subjects at high cardiovascular risk

Cardioprotective effect of the mitochondrial unfolded protein response during chronic pressure overload

Background The mitochondrial unfolded protein response (UPRmt) is activated when misfolded proteins accumulate within mitochondria and leads to increased expression of mitochondrial chaperones and proteases to maintain protein quality and mitochondrial function. Cardiac mitochondria are essential for contractile function and regulation of cell viability, while mitochondrial dysfunction characterizes heart failure. The role of the UPRmt in the heart is unclear. Objectives The purpose of this study was to: 1) identify conditions that activate the UPRmt in the heart; and 2) study the relationship among the UPRmt, mitochondrial function, and cardiac contractile function. Methods Cultured cardiac myocytes were subjected to different stresses in vitro. Mice were subjected to chronic pressure overload. Tissues and blood biomarkers were studied in patients with aortic stenosis. Results Diverse neurohumoral or mitochondrial stresses transiently induced the UPRmt in cultured cardiomyocytes. The UPRmt was also induced in the hearts of mice subjected to chronic hemodynamic overload. Boosting the UPRmt with nicotinamide riboside (which augments NAD+ pools) in cardiomyocytes in vitro or hearts in vivo significantly mitigated the reductions in mitochondrial oxygen consumption induced by these stresses. In mice subjected to pressure overload, nicotinamide riboside reduced cardiomyocyte death and contractile dysfunction. Myocardial tissue from patients with aortic stenosis also showed evidence of UPRmt activation, which correlated with reduced tissue cardiomyocyte death and fibrosis and lower plasma levels of biomarkers of cardiac damage (high-sensitivity troponin T) and dysfunction (N-terminal pro–B-type natriuretic peptide). Conclusions These results identify the induction of the UPRmt in the mammalian (including human) heart exposed to pathological stresses. Enhancement of the UPRmt ameliorates mitochondrial and contractile dysfunction, suggesting that it may serve an important protective role in the stressed heart

Nut Consumptions as a Marker of Higher Diet Quality in a Mediterranean Population at High Cardiovascular Risk

Background: Nut consumption has been associated with improved nutrient adequacy and diet quality in healthy adult populations but this association has never been explored in individuals at high cardiovascular risk. Objective: to assess the associations between consumption of nuts and nutrient adequacy and diet quality in a Mediterranean population at high cardiovascular risk. Design: baseline assessment of nutritional adequacy in participants (n = 6060, men and women, with ages 55⁻75 years old, with overweight/obesity and metabolic syndrome) in the PREDIMED-PLUS primary cardiovascular prevention randomized trial. Methods: nut intake was assessed using a validated food frequency questionnaire. Participants who reported consuming zero quantity of nuts were classified as 'non-nut consumers'. 'Nut consumers' were participants who reported consuming any quantity of nuts. Nineteen micronutrients were examined (vitamins B1, B2, B3, B6, B12, A, C, D, E and folic acid; Ca, K, P, Mg, Fe, Se, Cr, Zn, and iodine). The proportion of micronutrient inadequacy was estimated using the estimated average requirements (EAR) or adequate intake (AI) cut-points. Diet quality was also assessed using a 17-item Mediterranean dietary questionnaire (Mediterranean diet score, MDS), a carbohydrate quality index (CQI) and a fat quality index (FQI). Results: eighty-two percent of participants were nut consumers (median of nut consumption 12.6 g/day; interquartile range: 6.0⁻25.2). Nut consumers were less likely to be below the EAR for vitamins A, B1, B2, B6, C, D, E, folic acid, and Ca, Mg, Se and Zn than non-nut consumers. Nut consumers were also more likely to be above the AI for K and Cr than non-nut consumers. Nut consumers had lower prevalence of inadequate micronutrient intakes, but also higher CQI, higher FQI, and better scores of adherence to the Mediterranean diet (Mediterranean diet score, MDS). Conclusions: nut consumers had better nutrient adequacy, diet quality, and adherence to the MedDiet than those non-nut consumers

Polymorphism of the transcription factor 7-like 2 gene (TCF7L2) interacts with obesity on type-2 diabetes in the PREDIMED study emphasizing the heterogeneity of genetic variants in type-2 diabetes risk prediction: time for obesity-specific genetic risk scores

Nutrigenetic studies analyzing gene–diet interactions of the TCF7L2-rs7903146 C > T polymorphism on type-2 diabetes (T2D) have shown controversial results. A reason contributing to this may be the additional modulation by obesity. Moreover, TCF7L2-rs7903146 is one of the most influential variants in T2D-genetic risk scores (GRS). Therefore, to increase the predictive value (PV) of GRS it is necessary to first see whether the included polymorphisms have heterogeneous effects. We comprehensively investigated gene-obesity interactions between the TCF7L2-rs7903146 C > T polymorphism on T2D (prevalence and incidence) and analyzed other T2D-polymorphisms in a sub-sample. We studied 7018 PREDIMED participants at baseline and longitudinally (8.7 years maximum follow-up). Obesity significantly interacted with the TCF7L2-rs7903146 on T2D prevalence, associations being greater in non-obese subjects. Accordingly, we prospectively observed in non-T2D subjects (n = 3607) that its association with T2D incidence was stronger in non-obese (HR: 1.81; 95% CI: 1.13–2.92, p = 0.013 for TT versus CC) than in obese subjects (HR: 1.01; 95% CI: 0.61–1.66; p = 0.979; p-interaction = 0.048). Accordingly, TCF7L2-PV was higher in non-obese subjects. Additionally, we created obesity-specific GRS with ten T2D-polymorphisms and demonstrated for the first time their higher strata-specific PV. In conclusion, we provide strong evidence supporting the need for considering obesity when analyzing the TCF7L2 effects and propose the use of obesity-specific GRS for T2D