The ratio of eicosapentaenoic acid to arachidonic acid is a critical risk factor for acute coronary syndrome in middle-aged older patients as well as younger adult patients

Blood indices of omega-3 and omega-6 polyunsaturated fatty acids are altered in hyperglycemia

Polyunsaturated fatty acids (PUFAs) may favorably influence the risk and clinical course of diabetes mellitus (DM). In particular, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA) alleviate oxidative injury and insulin resistance characteristic of DM. Uncertainty still remains, however, as to the composition and proportions of blood PUFAs in relation to fasting blood glucose levels. This study, thus, aims to examine the patterns of blood PUFA indices in normoglycemic (NG) and hyperglycemic (HG) Saudi subjects. Age, gender, FA profiles, and laboratory records of 143 subjects collected from September 2014 to March 2018 were retrospectively analyzed. Means, prevalence rates, associations, risk measures, and the diagnostic accuracy of PUFAs were determined. HG subjects had significantly lower AA (0.70%, 95% CI: 0.59-0.80% vs 0.46%, 95% CI: 0.38-0.53%) and higher EPA/AA ratio (0.36, 95% CI: 0.30-0.42 vs 0.69, 95% CI: 0.61-0.77). Gender-wise comparisons revealed that ώ-6/ώ-3 ratio was the only PUFA index significantly elevated in HG males (0.36, 95% CI: 0.26-0.45 vs 5.68, 95% CI: 4.98-6.38) while both DHA (2.91%, 95% CI: 2.54-3.29% vs 3.37%, 95% CI: 3.13-3.60%) and ώ-3 index (3.1%, 95% CI: 2.70-3.49% vs 3.63%, 95% CI: 3.38-3.88%) were significantly elevated in HG females. Furthermore, reduced AA and elevated EPA/AA ratio were more prevalent in HG subjects (26.53 vs 28.72 and 30.61 vs 38.29, respectively) and exhibited the highest diagnostic accuracy for HG among all PUFA indices. Altogether, our study revealed that distinct, gender-specific blood PUFA indices are differentially regulated in HG subjects which may be valuable for DM management.

Omega-3 index and AA/EPA ratio as biomarkers of running-related injuries: An observational study in recreational runners

ABSTRACTThe aim of this study was to examine the association between biomarkers of polyunsaturated fatty acids (PUFA), such as omega-3 (ω-3) index and arachidonic acid (AA; 20:4 ω-6)/eicosapentaenoic acid (EPA; 20:5ω-3) ratio (AA/EPA), and the prevalence of running-related injuries (RRI) in a cohort of recreational runners. We performed a retrospective, observational study of 275 non-elite runners (mean age: 41.20 ± 12.47 years) who were not supplemented with ω-3 fatty acids. The training characteristics and RRI were recorded over a period of 12 months through a self-reported questionnaire. Using whole blood samples collected by finger prick, PUFA were quantified by gas chromatography and ω-3 index and AA/EPA ratio measured. A total of 191 RRI cases were reported, with an injury prevalence rate of 50.9% in the overall population. The injured runners ran a significantly greater weekly distance than uninjured subjects (53.54 ± 25.27 km/week; p = 0.007). In a multivariate regression analysis, the lowest number of RRI was associated with higher values of ω-3 index (β = - 0.237; 95% CI - 0.308 to - 0.164; R² = 0.172; p < 0.0001), while a higher AA/EPA ratio was correlated with higher number of RRI (β = 0.019; 95% CI 0.007-0.031; R² = 0.038; p = 0.003). This study identifies ω-3 index and AA/EPA ratio as potential parameters associated with the risk of RRI. Future research is needed to confirm these results and apply specific nutritional strategies to successfully modify these biochemical variables.Trial registration: ISRCTN.org identifier: ISRCTN12847156..

Association between the ratio of serum eicosapentaenoic acid to arachidonic acid and risk of coronary artery disease in young Chinese patients

Objective

Long-chain (LC) omega-3 PUFAs, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may play an anti-inflammatory effect and decrease the risk of coronary artery disease (CAD). In contrast, omega-6 PUFA, mainly arachidonic acid (AA), has pro-inflammatory and pro-aggregatory effects, which may increase the risk of CAD. This study evaluated the associations between EPA, DHA, AA, and their ratios (EPA/AA and DHA/AA) with the risk of CAD in young Chinese patients.

Methods

A total of 182 young patients with CAD and 143 age-matched controls were included. Traditional cardiovascular risk factors were recorded. Serum EPA, DHA and AA were measured by ultra-performance liquid chromatography-mass spectrometry.

Results

The level of AA was significantly higher, while the level of EPA was lower in the CAD group than that in the control group. There was no significant difference in DHA level in the two groups. Both the ratios of EPA/AA and DHA/AA were lower in the CAD group than that in the control. Multivariate logistic regression analysis showed that higher serum AA level was associated with the increased risk of CAD, while EPA was a protective factor for CAD. There was no significant association between DHA level and the risk of CAD. Although both higher ratios of EPA/AA [per tertile increment, adjusted odds ratios (ORs) (OR) 0.356, 95% confidence intervals (CI) 0.247–0.513] and DHA/AA (adjusted OR = 0.465, 95%CI = 0.332–0.653) were associated with a lower risk of CAD in young patients. Receiver operating characteristic (ROC) curve analysis showed that compared with AA, the diagnostic value was increased in EPA/AA, but not in DHA/AA.

Conclusion

EPA, but not DHA may play a protective role in CAD, while AA may be associated with the increased risk of CAD in young Chinese patients. The ratio of EPA/AA can increase the predictive value for diagnosing CAD than EPA or AA alone.

Fatty acid desaturase genetic variations and dietary omega-3 fatty acid intake associate with arterial stiffness

Aims

Long-chain polyunsaturated fatty acids (PUFAs) generate diverse bioactive lipid mediators, which tightly regulate vascular inflammation. The effects of omega-3 PUFA supplementation in cardiovascular prevention however remain controversial. In addition to direct dietary intake, fatty acid desaturases (FADS) determine PUFA levels. Increased arterial stiffness represents an independent predictor of mortality and cardiovascular events. The aim of the present study was to determine the association of PUFA intake, FADS1 genotype, and FADS expression with arterial stiffness.

Methods and results

A cross-sectional population-based cohort study of 1464 participants without overt cardiovascular disease was conducted. Dietary intake was assessed using a food frequency questionnaire. Arterial stiffness was assessed by carotid–femoral pulse wave velocity (cfPWV), and the FADS1 locus variant was determined. Blood cell transcriptomics was performed in a subset of 410 individuals. Pulse wave velocity was significantly associated with the FADS1 locus variant. Differential associations between PWV and omega-3 PUFA intake were observed depending on the FADS1 genotype. High omega-3 PUFA intake attenuated the FADS1 genotype-dependent associations. Carriers of the minor FADS1 locus variant exhibited increased expression of FADS2, which is associated with PWV.

Conclusion

Taken together, these findings point to FADS1 genotype-dependent associations of omega-3 PUFA intake on subclinical cardiovascular disease. These findings may have implications for identifying responders and non-responders to omega-3 PUFA supplementation and open up for personalized dietary counselling in cardiovascular prevention.

Depletion of Omega-3 Fatty Acids in RBCs and Changes of Inflammation Markers in Patients With Morbid Obesity Undergoing Gastric Bypass

BACKGROUND

Bariatric surgery is considered the most effective treatment for severe obesity. Despite this wide success, bariatric surgery is associated with increased risks of nutritional deficiencies.

OBJECTIVES

To examine whether Roux-en-Y-gastric bypass (RYGB) alters essential fatty acid (FA) status and inflammation markers.

METHODS

Subjects with obesity (n = 28; BMI > 40 kg/m2; mean age 48 years) were studied before and 1 year after RYGB. We collected blood samples before and 12 months after RYGB, and analyzed FA in RBCs and peripheral blood mononuclear cells (PBMC), and measured inflammation parameters in plasma. The proportion of total n-3 FAs was the primary outcome, while parameters related to other FAs and inflammation factors were the secondary parameters. In addition, PBMCs from 15 of the participants were cultured alone or with 100 and 200 μM DHA, and the production of IL-6, IL-1β, PGE2, and prostaglandin F2-alpha (PGF2α) was assayed after endotoxin (LPS) stimulation.

RESULTS

RYGB induced a significant reduction of BMI (-30%) and improvement of insulin resistance (-49%). While the proportion of arachidonic acid was 15% higher after RYGB, the proportions of total and individual n-3 FAs were 50%-75% lower (P < 0.01). Consequently, the RBC omega-3 index and n-3:n-6 fatty acid ratio were 45% and 50% lower after surgery, respectively. In isolated PBMCs, LPS induced the production of IL-6, IL-1β, PGE2, and PGF2α in both pre- and post-RYGB cells, but the effects were 34%-65% higher (P < 0.05) after RYGB. This effect was abrogated by DHA supplementation.

CONCLUSIONS

This study presents evidence that RBC and PBMC n-3 FAs are severely reduced in patients with obesity after RYGB. DHA supplementation in PBMC moderates the production of inflammation markers, suggesting that n-3 FA supplementation would merit a trial in bariatric patients.

Metabolic indices of polyunsaturated fatty acids: current evidence, research controversies, and clinical utility

The n-3 and n-6 polyunsaturated fatty acids (PUFA) are among the most studied nutrients in human metabolism. In the past few decades, prospective studies and controlled trials have supported the view that the effects of these essential fatty acids are clinically relevant. PUFA profiles in different blood compartments are reflections of both diet and metabolism, and their levels may be related to disease risk. Despite widespread interest, there is no consensus regarding which biomarkers best reflect PUFA status in the body. The measurement of PUFA levels is not straight-forward, and a wide variety of indices have been used in clinical studies, producing conflicting results. A major source of heterogeneity among studies is associated with research design, sampling, and laboratory analyses. To date, the n-3 index, n-6/n-3 ratio, and arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio are the most promising biomarkers associated with PUFA metabolism. Although hotly debated, these indices may be considered at least markers, if not risk factors, for several diseases, especially cardiovascular events and brain disorders. Here, we summarize the most updated evidence of n-3 and n-6 PUFA effects on human health, reviewing current controversies on the aforementioned indices and whether they can be considered valuable predictors of clinical outcomes.

Cardiovascular, electrophysiologic, and hematologic effects of omega-3 fatty acids beyond reducing hypertriglyceridemia: as it pertains to the recently published REDUCE-IT trial

Heart disease continues to affect health outcomes globally, accounting for a quarter of all deaths in the United States. Despite the improvement in the development and implementation of guideline-directed medical therapy, the risk of adverse cardiac events remains substantially high. Historically, it has been debated whether omega-3 polyunsaturated fatty acids provide clinical benefit in cardiac disease. The recently published REDUCE-IT trial demonstrated a statistically significant absolute risk reduction of 4.8% in its primary endpoint (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or unstable angina) with the use of icosapent ethyl, which is a highly purified eicosapentaenoic acid (EPA) ethyl ester. However, the mechanism of action of omega-3 fatty acids is not commonly discussed. Moreover, the use of EPA was not without risk, as the incidence of atrial fibrillation was increased along with a trend towards increased bleeding risk. Thus, our aim is to help explain the function of purified EPA ethyl ester, especially at the molecular level, which will ultimately lead to a better understanding of their clinically observable effects.

The eicosapentaenoic acid:arachidonic acid ratio and its clinical utility in cardiovascular disease

Eicosapentaenoic acid (EPA) is a key anti-inflammatory/anti-aggregatory long-chain polyunsaturated omega-3 fatty acid. Conversely, the omega-6 fatty acid, arachidonic acid (AA) is a precursor to a number of pro-inflammatory/pro-aggregatory mediators. EPA acts competitively with AA for the key cyclooxygenase and lipoxygenase enzymes to form less inflammatory products. As a result, the EPA:AA ratio may be a marker of chronic inflammation, with a lower ratio corresponding to higher levels of inflammation. It is now well established that inflammation plays an important role in cardiovascular disease. This review examines the role of the EPA:AA ratio as a marker of cardiovascular disease and the relationship between changes in the ratio (mediated by EPA intake) and changes in cardiovascular risk. Epidemiological studies have shown that a lower EPA:AA ratio is associated with an increased risk of coronary artery disease, acute coronary syndrome, myocardial infarction, stroke, chronic heart failure, peripheral artery disease, and vascular disease. Increasing the EPA:AA ratio through treatment with purified EPA has been shown in clinical studies to be effective in primary and secondary prevention of coronary artery disease and reduces the risk of cardiovascular events following percutaneous coronary intervention. The EPA:AA ratio is a valuable predictor of cardiovascular risk. Results from ongoing clinical trials will help to define thresholds for EPA treatment associated with better clinical outcomes.

Relationship Between Distance Run Per Week, Omega-3 Index, and Arachidonic Acid (AA)/Eicosapentaenoic Acid (EPA) Ratio: An Observational Retrospective Study in Non-elite Runners

Background: Tissue availability of polyunsaturated fatty acids (PUFA) depends on several factors, including dietary intake, physical exercise, genetic variation, and metabolic turnover. However, there is limited evidence whether running training activity per se may influence indices associated with PUFA metabolism such as Omega-3 (ω-3) index and arachidonic acid (AA; 20:4ω-6)/eicosapentaenoic acid (EPA; 20:5ω-3) ratio.

Objective: To examine the association between kilometers (Km) run per week and changes in ω-3 index and AA/EPA ratio.

Methods: We conducted a retrospective, observational, cohort study of 257 non-elite runners (mean age: 40.85 ± 12.17 years) who consumed no fatty acid supplements and provided a blood sample for analysis. The whole blood samples were collected by finger sticks, stored on absorbent filter paper, and then PUFA were quantified by gas chromatography (GC) and ω-3 index and AA/EPA ratio measured.

Results: In a multivariate linear regression model, a gradual decrease of the ω-3 index was observed with higher weekly running distance (β = −0.033; 95% CI −0.039 to −0.026; R² = 0.447; p < 0.0001). We also found a progressive increase of the AA/EPA ratio in subjects who ran greater weekly distances (β = 0.092; 95% CI 0.038 to 0.146; R² = 0.320; p = 0.001). No other significant associations were observed with other variables, including years of running training and weekly training frequency (hours/week). Finally, as expected, a significant inverse correlation between ω-3 index and AA/EPA ratio (β = −2.614; 95% CI −3.407 to −1.821; R² = 0.336; p < 0.0001) was detected.

Conclusions: These findings suggest that distance running training and its weekly volume may negatively contribute to changes of the ω-3 index and AA/EPA ratio. Further studies with greater sample size will be required to replicate and extend these data.

Variations in the eicosapentaenoic acid-arachidonic acid ratio associated with age in acute myocardial infarction patients undergoing primary percutaneous coronary intervention

Acute myocardial infarction (AMI) is a life-threatening disease, and its incidence has been increasing even in the young population. Although a low eicosapentaenoic acid (EPA)-arachidonic acid (AA) ratio is associated with an increased risk of coronary artery disease, the effect of age on EPA/AA ratios in AMI patients remains unclear. This study aimed to clarify the independent polyunsaturated fatty acid (PUFA)-related determinants of age in younger and older AMI patients. A total of 153 consecutive patients who underwent primary percutaneous coronary interventions (PCIs) for de novo AMIs were enrolled in this study. Patients' background data, including PUFA and lipid profiles during PCI, were evaluated retrospectively. The EPA/AA ratio correlated positively with age (r = 0.21; P = 0.011) and increased markedly from age 60 years. Patients aged < 60 years (n = 35) had a lower mean EPA/AA ratio (0.25 ± 0.16) than patients aged ≥ 60 years (n = 118) (0.38 ± 0.25) (P < 0.001). The AA level was more dependent on age than on EPA level (r = - 0.34, P < 0.001 vs. r = 0.12, P = 0.16). The multivariate analysis revealed that a 0.1 EPA/AA ratio increase (odds ratio 1.50; 95% confidence interval 1.09-2.06), body mass index, triglyceride level, and aspirin administration were independently associated with the age stratification of AMI patients. The EPA/AA ratio was higher in younger AMI patients who have undergone primary PCIs than in older patients. Younger population at risk for AMI should be managed with multiple interventions including PUFA profiling.

Silent myocardial ischemia in asymptomatic patients with type 2 diabetes mellitus without previous histories of cardiovascular disease

BACKGROUND

The number of patients with type 2 diabetes mellitus (T2DM) continues to increase all over the world. Cardiovascular disease (CVD), especially coronary artery disease (CAD), is a major cause of the morbidity and mortality in patients with T2DM. The prognosis of patients with silent myocardial ischemia (SMI) is worse than that in those without.

METHODS AND RESULTS

Thus, to assess how many patients with SMI existed among those patients, CVD screening tests were performed in 128 asymptomatic patients with T2DM without previous histories of CVD. SMI could be detected in 24 patients (19%) by exercise stress tests and/or the coronary fractional flow reserve. Their 12-lead electrocardiogram and cardiac ultrasonography were both normal. Compared to those without SMI, those with had a statistically significant longer history of T2DM (17±1 versus 11±1years, p=0.006), and the co-existence of a family history of CVD (42% versus 21%, p=0.037). Furthermore, these factors were demonstrated as independent risk factors of SMI by a multivariate analysis (Odds ratio 1.060 and 4.000, respectively), and in accordance with the disease duration of T2DM, the prevalence of patients with SMI has been increasing (p=0.019).

CONCLUSIONS

Physicians should be aware of these conditions when examining patients with T2DM, especially with a family history of CVD and/or long disease duration (>11years) of T2DM, even though they have no symptoms, previous histories of CVDs, and/or abnormal findings on the 12-lead electrocardiogram and cardiac ultrasonography. This may be an effective, safe, and attractive diagnostic strategy for those asymptomatic patients with T2DM.

Low eicosapentaenoic acid to arachidonic acid ratio is associated with thin-cap fibroatheroma determined by optical coherence tomography

BACKGROUND

A low eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio is known to be associated with cardiovascular events. However, the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by optical coherence tomography (OCT) has not been examined thoroughly. This study examined the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by OCT in patients with acute coronary syndrome (ACS).

METHODS

We evaluated 59 ACS patients who had undergone percutaneous coronary intervention using OCT. We divided them into 2 groups according to OCT findings-those with and without thin-cap fibroatheroma (TCFA)-and compared the EPA/AA ratio between the groups.

RESULTS

We identified 32 and 27 patients with and without TCFA, respectively. The EPA/AA ratio was significantly lower in patients with TCFA than in those without TCFA [0.35, interquartile range (0.21-0.44) vs. 0.54, interquartile range (0.42-0.70); p<0.001]. In multivariate logistic regression analysis, the EPA/AA ratio was an independent predictor of TCFA (odds ratio, 0.09; 95% confidence interval, 0.007-0.99; p=0.049). The EPA/AA ratio and fibrous cap thickness showed a significant positive correlation (Spearman ρ=0.46; p<0.001). Furthermore, receiver operating characteristic curve analysis showed that an EPA/AA ratio<0.46 could predict TCFA (81.3%, sensitivity; 74.1%, specificity).

CONCLUSIONS

A low serum EPA/AA ratio is significantly associated with coronary plaque vulnerability assessed by OCT in ACS patients.

Association between serum long-chain n-3 and n-6 polyunsaturated fatty acid profiles and glomerular filtration rate assessed by serum creatinine and cystatin C levels in Japanese community-dwellers

Background

Plasma concentration of n-3 polyunsaturated fatty acids (PUFAs) has been reported to be associated with renal function in Western populations. However, few studies have investigated the association between serum long-chain n-3 and n-6 PUFA profiles and renal function in a Japanese population with high marine-derived long-chain n-3 PUFA intake.

Methods

A cross-sectional study was performed in 549 Japanese rural community-dwellers aged 40 to 64 years. In adjusted analysis of covariance, we assessed the relationship between estimated glomerular filtration rate (eGFR) and tertiles of serum long-chain n-3 and n-6 PUFA profiles ([eicosapentaenoic acid {EPA} + docosahexaenoic acid {DHA}]:arachidonic acid [AA]). GFR was estimated by Japanese specific equations using serum creatinine and cystatin C (eGFR_cre and eGFR_cys). Using multivariate-adjusted linear regression models, we also assessed the relationships between eGFRs and several n-3 and n-6 PUFAs, which have been suggested to be associated with renal function.

Results

In all participants, higher dietary fish intake as assessed by a semi-quantitative questionnaire was associated with higher serum value of (EPA+DHA):AA. Participants in the higher (EPA+DHA):AA tertiles had non-significantly higher eGFR_cre and significantly higher eGFR_cys (P = 0.016). In addition, eGFR_cys in T₂+T₃ of (EPA+DHA):AA was significantly higher than that in T₁ (adjusted mean eGFR_cys, T₁: 87 ml/min/1.73 m², T₂+T₃: 91 ml/min/1.73 m²; P < 0.01). Among the PUFAs, only (EPA+DHA) was significantly associated with eGFR_cys.

Conclusions

Serum (EPA+DHA):AA, which reflects an individual’s fish intake, might be associated with eGFR_cys in Japanese community-dwellers.

Eicosapentaenoic acid/arachidonic acid ratio and smoking status in elderly patients with type 2 diabetes mellitus

BACKGROUND

A low ratio of eicosapentaenoic acid (EPA)/arachidonic acid (AA) is considered a risk factor for cardiovascular disease. Smoking is also a risk factor for cardiovascular disease even in an elderly population. This study investigated the relationship between EPA/AA ratio and smoking status among elderly patients with type 2 diabetes mellitus (T2DM).

FINDINGS

A total of 188 elderly patients with T2DM (men/women, 114/74; mean age, 65.0 ± 7.5 years) were studied in terms of their smoking status, diabetic conditions, and blood data, including EPA and AA. Current smokers showed a lower EPA/AA ratio than non-smokers (current smokers: 0.29, n = 49; non-smokers: 0.39, n = 139, p < 0.01). This relationship remained significant after adjusting for multiple variables.

CONCLUSIONS

Smoking may affect the EPA/AA ratio among elderly patients with T2DM, suggesting a possible mechanism of cardiovascular disease development and indicating the importance of smoking secession in such patients.