Omega-3 fatty acids in high-risk cardiovascular patients: a meta-analysis of randomized controlled trials

<p>Abstract</p> <p>Background</p> <p>Multiple randomized controlled trials (RCTs) have examined the cardiovascular effects of omega-3 fatty acids and have provided unexplained conflicting results. A meta-analysis of these RCTs to estimate efficacy and safety and potential sources of heterogeneity may be helpful.</p> <p>Methods</p> <p>The Cochrane library, MEDLINE, and EMBASE were systematically searched to identify all interventional trials of omega-3 fatty acids compared to placebo or usual diet in high-risk cardiovascular patients. The primary outcome was all-cause mortality and secondary outcomes were coronary restenosis following percutaneous coronary intervention and safety. Meta-analyses were carried out using Bayesian random-effects models, and heterogeneity was examined using meta-regression.</p> <p>Results</p> <p>A total of 29 RCTs (n = 35,144) met our inclusion criteria, with 25 reporting mortality and 14 reporting restenosis. Omega-3 fatty acids were not associated with a statistically significant decreased mortality (relative risk [RR] = 0.88, 95% Credible Interval [CrI] = 0.64, 1.03) or with restenosis prevention (RR = 0.89, 95% CrI = 0.72, 1.06), though the probability of some benefit remains high (0.93 and 0.90, respectively). However in meta-regressions, there was a >90% probability that larger studies and those with longer follow-up were associated with smaller benefits. No serious safety issues were identified.</p> <p>Conclusions</p> <p>Although not reaching conventional statistical significance, the evidence to date suggests that omega-3 fatty acids may result in a modest reduction in mortality and restenosis. However, caution must be exercised in interpreting these benefits as results were attenuated in higher quality studies, suggesting that bias may be at least partially responsible. Additional high quality studies are required to clarify the role of omega-3 fatty acid supplementation for the secondary prevention of cardiovascular disease.</p

Factors influencing gastrointestinal tract and microbiota immune interaction in preterm infants

The role of microbial colonization is indispensable for keeping a balanced immune response in life. However, the events that regulate the establishment of the microbiota, their timing, and the way in which they interact with the host are not yet fully understood. Factors such as gestational age, mode of delivery, environment, hygienic measures, and diet influence the establishment of microbiota in the perinatal period. Environmental microbes constitute the most important group of exogenous stimuli in this critical time frame. However, the settlement of a stable gut microbiota in preterm infants is delayed compared to term infants. Preterm infants have an immature gastrointestinal tract and immune system which predisposes to infectious morbidity. Neonatal microbial dynamics and alterations in early gut microbiota may precede and/or predispose to diseases such as necrotizing enterocolitis (NEC), late-onset sepsis or others. During this critical period, nutrition is the principal contributor for immunological and metabolic development, and microbiological programming. Breast milk is a known source of molecules that act synergistically to protect the gut barrier and enhance the maturation of the gut-related immune response. Host-microbe interactions in preterm infants and the protective role of diet focused on breast milk impact are beginning to be unveiled.M.C. acknowledges a “Rio Hortega” Research Fellowship Grant (CM13/0017) and M.V. acknowledges grants PI11/0313 and RD12/0026/0012 (Red SAMID) from the Instituto Carlos III (Spanish Ministry of Economy and Competitivity). M.C.C. and G.P-M. were supported by the grant AGL2013-47420-R from the Spanish Ministry of Science and Innovation.Peer reviewe

Omega-3 in Antiarrhythmic Therapy

The association between omega-3 (n-3 polyunsaturated fatty acids) and the clinical outcome of patients with cardiovascular diseases such as coronary heart disease is currently unclear, especially regarding its possible antiarrhythmic effects and the not quite understood mechanisms of action. In the last 15 years, several epidemiological studies have shown a lower incidence of sudden cardiac death with a diet rich in omega-3 or fish consumption. The antiarrhythmic properties related to omega-3 have been related to modulation of sodium-dependent ion channels or sodium-calcium exchangers of myocytes through a reduction of their excitability especially in ischaemic or damaged myocardial tissue. However, the results of experimental studies have not always been consistent. Although the role of omega-3 in preventing sudden cardiac death has been evaluated in several clinical trials that included patients with coronary artery disease (particularly in patients with post-myocardial infarction), the interpretation of such data must be treated with extreme caution. In particular, while a reduction in cardiac death was demonstrated by a meta-analysis of several randomized clinical trials, a reduced risk of sudden cardiac death has been described only in the GISSI-Prevenzione study, while in other studies the evidence that emerged is more controversial, with wide confidence intervals that support the possibility of heterogeneity in the distribution of the factors involved in the efficacy of treatment. Omega-3 is probably involved in the prevention of cardiovascular mortality through different mechanisms, and it is crucial to study its association with other drugs such as ACE inhibitors or calcium channel blockers. The study of antiarrhythmic drugs has been divided into prevention of supraventricular and ventricular arrhythmias. In these conditions, the role of omega-3 seems to be more pronounced in atrial tachyarrhythmias such as atrial fibrillation, but does not have a role in ventricular arrhythmias. In summary, the antiarrhythmic effect of omega-3 is not clearly evident and further studies are needed to investigate its beneficial effect in cardiac mortality compared with arrhythmic death