The omega-3 index in patients with heart failure: A prospective cohort study

Trans-fatty acid blood levels of industrial but not natural origin are associated with cardiovascular risk factors in patients with HFpEF: a secondary analysis of the Aldo-DHF trial

BACKGROUND

Industrially processed trans-fatty acids (IP-TFA) have been linked to altered lipoprotein metabolism, inflammation and increased NT-proBNP. In patients with heart failure with preserved ejection fraction (HFpEF), associations of TFA blood levels with patient characteristics are unknown.

METHODS

This is a secondary analysis of the Aldo-DHF-RCT. From 422 patients, individual blood TFA were analyzed at baseline in n = 404 using the HS-Omega-3-Index® methodology. Patient characteristics were: 67 ± 8 years, 53% female, NYHA II/III (87/13%), ejection fraction ≥ 50%, E/e' 7.1 ± 1.5; NT-proBNP 158 ng/L (IQR 82-298). A principal component analysis was conducted but not used for further analysis as cumulative variance for the first two PCs was low. Spearman's correlation coefficients as well as linear regression analyses, using sex and age as covariates, were used to describe associations of whole blood TFA with metabolic phenotype, functional capacity, echocardiographic markers for LVDF and neurohumoral activation at baseline and after 12 months.

RESULTS

Blood levels of the naturally occurring TFA C16:1n-7t were inversely associated with dyslipidemia, body mass index/truncal adiposity, surrogate markers for non-alcoholic fatty liver disease and inflammation at baseline/12 months. Conversely, IP-TFA C18:1n9t, C18:2n6tt and C18:2n6tc were positively associated with dyslipidemia and isomer C18:2n6ct with dysglycemia. C18:2n6tt and C18:2n6ct were inversely associated with submaximal aerobic capacity at baseline/12 months. No significant association was found between TFA and cardiac function.

CONCLUSIONS

In HFpEF patients, higher blood levels of IP-TFA, but not naturally occurring TFA, were associated with dyslipidemia, dysglycemia and lower functional capacity. Blood TFAs, in particular C16:1n-7t, warrant further investigation as prognostic markers in HFpEF. Higher blood levels of industrially processed TFA, but not of the naturally occurring TFA C16:1n-7t, are associated with a higher risk cardiometabolic phenotype and prognostic of lower aerobic capacity in patients with HFpEF.

Omega-3 fatty acids in heart disease-why accurately measured levels matter

Current guidelines barely support marine omega‑3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in cardiology, mainly because results of large trials were equivocal. Most large trials have tested EPA alone or EPA + DHA combined as a drug, thereby disregarding the relevance of their blood levels. These levels are frequently assessed with the Omega‑3 Index (percentage of EPA + DHA in erythrocytes), which is determined using a specific standardised analytical procedure. EPA and DHA are present in every human being at unpredictable levels (even in the absence of intake), and their bioavailability is complex. Both facts need to be incorporated into trial design and should direct clinical use of EPA and DHA. An Omega‑3 Index in the target range of 8-11% is associated with lower total mortality, fewer major adverse cardiac and other cardiovascular events. Moreover, functions of organs such as the brain benefit from an Omega‑3 Index in the target range, while untoward effects, such as bleeding or atrial fibrillation, are minimised. In pertinent intervention trials, several organ functions were improved, with improvements correlating with the Omega‑3 Index. Thus, the Omega‑3 Index is relevant in trial design and clinical medicine, which calls for a widely available standardised analytical procedure and a discussion on possible reimbursement of this test.

De Novo Lipogenesis-Related Monounsaturated Fatty Acids in the Blood Are Associated with Cardiovascular Risk Factors in HFpEF Patients

De novo lipogenesis (DNL)-related monounsaturated fatty acids (MUFAs) in the blood are associated with incident heart failure (HF). This observation's biological plausibility may be due to the potential of these MUFAs to induce proinflammatory pathways, endoplasmic reticulum stress, and insulin resistance, which are pathophysiologically relevant in HF. The associations of circulating MUFAs with cardiometabolic phenotypes in patients with heart failure with a preserved ejection fraction (HFpEF) are unknown. In this secondary analysis of the Aldosterone in Diastolic Heart Failure trial, circulating MUFAs were analysed in 404 patients using the HS-Omega-3-Index® methodology. Patients were 67 ± 8 years old, 53% female, NYHA II/III (87/13%). The ejection fraction was ≥50%, E/e' 7.1 ± 1.5, and the median NT-proBNP 158 ng/L (IQR 82-298). Associations of MUFAs with metabolic, functional, and echocardiographic patient characteristics at baseline/12 months follow-up (12 mFU) were analysed using Spearman's correlation coefficients and linear regression analyses, using sex/age as covariates. Circulating levels of C16:1n7 and C18:1n9 were positively associated with BMI/truncal adiposity and associated traits (dysglycemia, atherogenic dyslipidemia, and biomarkers suggestive of non-alcoholic-fatty liver disease). They were furthermore inversely associated with functional capacity at baseline/12 mFU. In contrast, higher levels of C20:1n9 and C24:1n9 were associated with lower cardiometabolic risk and higher exercise capacity at baseline/12 mFU. In patients with HFpEF, circulating levels of individual MUFAs were differentially associated with cardiovascular risk factors. Our findings speak against categorizing FA based on physicochemical properties. Circulating MUFAs may warrant further investigation as prognostic markers in HFpEF.

The Association of Metabolomic Profiles of a Healthy Lifestyle with Heart Failure Risk in a Prospective Study

Lifestyle has been linked to the incidence of heart failure, but the underlying biological mechanisms remain unclear. Using the metabolomic, lifestyle, and heart failure data of the UK Biobank, we identified and validated healthy lifestyle-related metabolites in a matched case-control and cohort study, respectively. We then evaluated the association of healthy lifestyle-related metabolites with heart failure (HF) risk and the added predictivity of these healthy lifestyle-associated metabolites for HF. Of 161 metabolites, 8 were identified to be significantly related to healthy lifestyle. Notably, omega-3 fatty acids and docosahexaenoic acid (DHA) positively associated with a healthy lifestyle score (HLS) and exhibited a negative association with heart failure risk. Conversely, creatinine negatively associated with a HLS, but was positively correlated with the risk of HF. Adding these three metabolites to the classical risk factor prediction model, the prediction accuracy of heart failure incidence can be improved as assessed by the C-statistic (increasing from 0.806 [95% CI, 0.796-0.816] to 0.844 [95% CI, 0.834-0.854], p-value < 0.001). A healthy lifestyle is associated with significant metabolic alterations, among which metabolites related to healthy lifestyle may be critical for the relationship between healthy lifestyle and HF. Healthy lifestyle-related metabolites might enhance HF prediction, but additional validation studies are necessary.

Saturated Fatty Acid Blood Levels and Cardiometabolic Phenotype in Patients with HFpEF: A Secondary Analysis of the Aldo-DHF Trial

Background: Circulating long-chain (LCSFAs) and very long-chain saturated fatty acids (VLSFAs) have been differentially linked to risk of incident heart failure (HF). In patients with heart failure with preserved ejection fraction (HFpEF), associations of blood SFA levels with patient characteristics are unknown. Methods: From the Aldo-DHF-RCT, whole blood SFAs were analyzed at baseline in n = 404 using the HS-Omega-3-Index^® methodology. Patient characteristics were 67 ± 8 years, 53% female, NYHA II/III (87%/13%), ejection fraction ≥50%, E/e’ 7.1 ± 1.5; and median NT-proBNP 158 ng/L (IQR 82–298). Spearman´s correlation coefficients and linear regression analyses, using sex and age as covariates, were used to describe associations of blood SFAs with metabolic phenotype, functional capacity, cardiac function, and neurohumoral activation at baseline and after 12-month follow-up (12 mFU). Results: In line with prior data supporting a potential role of de novo lipogenesis-related LCSFAs in the development of HF, we showed that baseline blood levels of C14:0 and C16:0 were associated with cardiovascular risk factors and/or lower exercise capacity in patients with HFpEF at baseline/12 mFU. Contrarily, the three major circulating VLSFAs, lignoceric acid (C24:0), behenic acid (C22:0), and arachidic acid (C20:0), as well as the LCSFA C18:0, were broadly associated with a lower risk phenotype, particularly a lower risk lipid profile. No associations were found between cardiac function and blood SFAs. Conclusions: Blood SFAs were differentially linked to biomarkers and anthropometric markers indicative of a higher-/lower-risk cardiometabolic phenotype in HFpEF patients. Blood SFA warrant further investigation as prognostic markers in HFpEF. One Sentence Summary: In patients with HFpEF, individual circulating blood SFAs were differentially associated with cardiometabolic phenotype and aerobic capacity.

The Influence of Eicosapentaenoic Acid to Arachidonic Acid Ratio on Long-term Cardiovascular Events Following Percutaneous Coronary Intervention

Objective The relationship between cardiovascular disease and the serum polyunsaturated fatty acid parameters has been reported. The aim of the present study was to investigate the association between the eicosapentaenoic acid and arachidonic acid (EPA/AA) ratio and long-term cardiovascular events in patients with coronary artery disease. Methods We identified a total of 831 patients who underwent percutaneous coronary intervention and whose EPA/AA ratio was available. The patients were divided into two groups according to their serum EPA/AA ratio (median, 0.29; interquartile range 0.19-0.47): those in the lower quartile of EPA/AA ratios (Low EPA/AA group; n=231) and all other subjects (High EPA/AA group; n=600). The primary endpoints included a composite of cardiovascular death, myocardial infarction, and ischemic stroke. Results Patients in the Low EPA/AA group were significantly younger (66.0±12.6 years vs. 69.9±9.3 years, p<0.001), current smokers (33.3% vs. 22.7%, p=0.002), and had a history of myocardial infarction (20.3% vs. 12.3%, p=0.003). During the follow-up (median, 1,206 days; interquartile range, 654-1,910 days), the occurrence of the primary endpoint was significantly higher in the Low EPA/AA group than in the High EPA/AA group. Of note, the rate of cardiovascular death was significantly higher in the Low EPA/AA group, and the rates of myocardial infarction and stroke tended to be higher. Conclusion A low EPA/AA ratio was associated with long-term adverse cardiovascular events in Japanese patients with coronary artery disease.

PUFA Supplementation and Heart Failure: Effects on Fibrosis and Cardiac Remodeling

Heart failure (HF) characterized by cardiac remodeling is a condition in which inflammation and fibrosis play a key role. Dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) seems to produce good results. In fact, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti-inflammatory and antioxidant properties and different cardioprotective mechanisms. In particular, following their interaction with the nuclear factor erythropoietin 2 related factor 2 (NRF2), the free fatty acid receptor 4 (Ffar4) receptor, or the G-protein coupled receptor 120 (GPR120) fibroblast receptors, they inhibit cardiac fibrosis and protect the heart from HF onset. Furthermore, n-3 PUFAs increase the left ventricular ejection fraction (LVEF), reduce global longitudinal deformation, E/e ratio (early ventricular filling and early mitral annulus velocity), soluble interleukin-1 receptor-like 1 (sST2) and high-sensitive C Reactive protein (hsCRP) levels, and increase flow-mediated dilation. Moreover, lower levels of brain natriuretic peptide (BNP) and serum norepinephrine (sNE) are reported and have a positive effect on cardiac hemodynamics. In addition, they reduce cardiac remodeling and inflammation by protecting patients from HF onset after myocardial infarction (MI). The positive effects of PUFA supplementation are associated with treatment duration and a daily dosage of 1–2 g. Therefore, both the European Society of Cardiology (ESC) and the American College of Cardiology/American Heart Association (ACC/AHA) define dietary supplementation with n-3 PUFAs as an effective therapy for reducing the risk of hospitalization and death in HF patients. In this review, we seek to highlight the most recent studies related to the effect of PUFA supplementation in HF. For that purpose, a PubMed literature survey was conducted with a focus on various in vitro and in vivo studies and clinical trials from 2015 to 2021.

Omega-3 index in 2018/19

The omega-3 index, the percentage of EPA plus DHA in erythrocytes (measured by standardised analysis), represents a human body's status in EPA and DHA. An omega-3 index is measured in many laboratories around the world; however, even small differences in analytical methods entail large differences in results. Nevertheless, results are frequently related to the target range of 8-11 %, defined for the original and scientifically validated method (HS-Omega-3 Index®), raising ethical issues, and calling for standardisation. No human subject has an omega-3 index <2 %, indicating a vital minimum. Thus, the absence of EPA and DHA cannot be tested against presence. Moreover, clinical events correlate with levels, less with the dose of EPA and DHA, and the bioavailability of EPA and DHA varies inter-individually. Therefore, the effects of EPA and DHA are difficult to demonstrate using typical drug trial methods. Recent epidemiologic data further support the relevance of the omega-3 index in the cardiovascular field, since total mortality, cardiovascular mortality, cardiovascular events such as myocardial infarction or stroke, or blood pressure all correlate inversely with the omega-3 index. The omega-3 index directly correlates with complex brain functions. Compiling recent data supports the target range for the omega-3 index of 8-11 % in pregnancy. Many other potential applications have emerged. Some, but not all health issues mentioned have already been demonstrated to be improved by increasing intake of EPA and DHA. Increasing the omega-3 index into the target range of 8-11 % with individualised doses of toxin-free sources for EPA and DHA is tolerable and safe.

Co-production of DHA and squalene by thraustochytrid from forest biomass

Omega-3 fatty acids, and specifically docosahexaenoic acid (DHA), are important and essential nutrients for human health. Thraustochytrids are recognised as commercial strains for nutraceuticals production, they are group of marine oleaginous microorganisms capable of co-synthesis of DHA and other valuable carotenoids in their cellular compartment. The present study sought to optimize DHA and squalene production by the thraustochytrid Schizochytrium limacinum SR21. The highest biomass yield (0.46 g/g_substrate) and lipid productivity (0.239 g/g_substrate) were observed with 60 g/L of glucose, following cultivation in a bioreactor, with the DHA content to be 67.76% w/w_{total lipids}. To reduce costs, cheaper feedstocks and simultaneous production of various value-added products for pharmaceutical or energy use should be attempted. To this end, we replaced pure glucose with organosolv-pretreated spruce hydrolysate and assessed the simultaneous production of DHA and squalene from S. limacinum SR21. After the 72 h of cultivation period in bioreactor, the maximum DHA content was observed to 66.72% w/w_{total lipids} that was corresponded to 10.15 g/L of DHA concentration. While the highest DHA productivity was 3.38 ± 0.27 g/L/d and squalene reached a total of 933.72 ± 6.53 mg/L (16.34 ± 1.81 mg/g_CDW). In summary, we show that the co-production of DHA and squalene makes S. limacinum SR21 appropriate strain for commercial-scale production of nutraceuticals.

[Confusion about the effects of omega-3 fatty acids : Contemplation of study data taking the omega-3 index into consideration]

BACKGROUND

Confusion reigns about omega‑3 fatty acids and their effects. Scientific investigations did not appear to clarify the issue. Guidelines and regulatory authorities contradict each other.

OBJECTIVE

This article provides clarity by considering not intake but levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes as a percentage of all fatty acids measured (omega‑3 index).

CURRENT DATA

The largest database of all methods of fatty acid analyses has been generated with the standardized HS-Omega‑3 Index® (Omegametrix, Martinsried, Deutschland). The omega‑3 index assesses the in EPA+DHA status of a person, has a minimum of 2%, a maximum of 20%, and is optimal between 8% and 11%. In many western countries but not in Japan or South Korea, mean levels are suboptimal. Suboptimal levels correlate with increased total mortality, sudden cardiac death, fatal and non-fatal myocardial infarction, other cardiovascular diseases, cognitive impairment, major depression, premature birth and other health issues. Interventional studies on surrogate and intermediary parameters demonstrated many positive effects, correlating with the omega‑3 index when measured. Due to issues in methodology that became apparent from the perspective of the omega‑3 index many, even large interventional trials with clinical endpoints were not positive, which is reflected in pertinent meta-analyses. In contrast, interventional trials without issues in methodology the clinical endpoints mentioned were reduced.

CONCLUSION

All humans have levels of EPA+DHA that if methodologically correctly assessed in erythrocytes, are optimal between 8% and 11%. Deficits can cause serious health issues that can be prevented by optimal levels.

Degenerative rotator cuff tears are associated with a low Omega-3 Index

BACKGROUND

The etiology of degenerative rotator cuff tears is multifactorial but chronic inflammation plays an important role in the pathogenesis. Some polyunsaturated fatty acids (PUFA) can modulate inflammation and marine n-3 (Omega-3) PUFA have anti-inflammatory effects. We hypothesized that the Omega-3 Index is lower in patients with degenerative rotator cuff tears when compared to controls without rotator cuff tendinopathy.

METHODS

From 684 consecutive patients with full thickness rotator cuff tears 655 were excluded because of possible bias. In the remaining 29 patients (22 m, 7 f; 53,9 y) with degenerative full thickness rotator-cuff tears, erythrocyte fatty acids were analyzed using the HS-Omega-3 Index^® methodology. 15 healthy volunteers (10 m, 5 f; 52.5y) served as a control.

RESULTS

The Omega-3 Index (% EPA + DHA) was 5.01% (95% CI: 3.81-4.66) in patients and 6.01% (95% CI: 4.48-5.72) in controls (p = 0.028) CONCLUSIONS: Patients with full thickness degenerative rotator cuff tears had a significantly lower Omega-3 Index than controls without rotator cuff tendinopathy. Whether a lower Omega-3 Index represents an independent risk factor for degenerative rotator cuff tears should be further investigated, e.g. in a longitudinal study.

The emerging role of omega-3 fatty acids as a therapeutic option in neuropsychiatric disorders

The prevalence of neurologic and psychiatric diseases has been increasing for decades and, given the moderate therapeutic efficacy and safety profile of existing pharmacological treatments, there is an urgent need for new therapeutic approaches. Nutrition has recently been recognized as an important factor for the prevention and treatment of neuropsychiatric disorders. The omega-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play critical roles in neuronal cell function and neurotransmission as well as inflammatory and immune reactions that are involved in neuropsychiatric disease states. A large number of experimental and epidemiological studies provide a strong basis for interventional clinical trials that assessed the clinical efficacy of n-3 PUFAs in various neurological and psychiatric disorders. Most of these trials found beneficial effects of dietary supplementation with EPA and DHA, and no serious safety concerns have emerged. This review gives an introduction to recent findings on the clinical efficacy of n-3 PUFAs in various neuropsychiatric disorders and the underlying biochemical mechanisms. In addition, the reader will be enabled to identify common methodological weaknesses of clinical studies on n-3 PUFAs, and suggestions for the design of future studies are given.