Prevention of postcoronary angioplasty restenosis by omega-3 fatty acids: main results of the Esapent for Prevention of Restenosis ITalian Study (ESPRIT)

Marine-derived n-3 fatty acids therapy for stroke

BACKGROUND

Currently, with stroke burden increasing, there is a need to explore therapeutic options that ameliorate the acute insult. There is substantial evidence of a neuroprotective effect of marine-derived n-3 polyunsaturated fatty acids (PUFAs) in animal models of stroke, leading to a better functional outcome.

OBJECTIVES

To assess the effects of administration of marine-derived n-3 PUFAs on functional outcomes and dependence in people with stroke.

SEARCH METHODS

We searched the Cochrane Stroke Trials Register (last searched 31 May 2021), the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 5), MEDLINE Ovid (from 1948 to 31 May 2021), Embase Ovid (from 1980 to 31 May 2021), CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; from 1982 to 31 May 2021), Science Citation Index Expanded ‒ Web of Science (SCI-EXPANDED), Conference Proceedings Citation Index-Science - Web of Science (CPCI-S), and BIOSIS Citation Index. We also searched ongoing trial registers, reference lists, relevant systematic reviews, and used the Science Citation Index Reference Search.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing marine-derived n-3 PUFAs to placebo or open control (no placebo) in people with a history of stroke or transient ischaemic attack (TIA), or both.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected trials for inclusion, extracted data, assessed risk of bias, and used the GRADE approach to assess the certainty of the body of evidence. We contacted study authors for clarification and additional information on stroke/TIA participants. We conducted random-effects meta-analysis or narrative synthesis, as appropriate. The primary outcome was efficacy (functional outcome) assessed using a validated scale, for example, the Glasgow Outcome Scale Extended (GOSE) dichotomised into poor or good clinical outcome, the Barthel Index (higher score is better; scale from 0 to 100), or the Rivermead Mobility Index (higher score is better; scale from 0 to 15). Our secondary outcomes were vascular-related death, recurrent events, incidence of other type of stroke, adverse events, quality of life, and mood.

MAIN RESULTS

We included 30 RCTs; nine of them provided outcome data (3339 participants). Only one study included participants in the acute phase of stroke (haemorrhagic). Doses of marine-derived n-3 PUFAs ranged from 400 mg/day to 3300 mg/day. Risk of bias was generally low or unclear in most trials, with a higher risk of bias in smaller studies. We assessed results separately for short (up to three months) and longer (more than three months) follow-up studies. Short follow-up (up to three months) Functional outcome was reported in only one pilot study as poor clinical outcome assessed with the GOSE (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.36 to 1.68, P = 0.52; 40 participants; very low-certainty evidence). Mood (assessed with the GHQ-30, lower score better) was reported by only one study and favoured control (mean difference (MD) 1.41, 95% CI 0.07 to 2.75, P = 0.04; 102 participants; low-certainty evidence). We found no evidence of an effect of the intervention for the remainder of the secondary outcomes: vascular-related death (two studies, not pooled due to differences in population, RR 0.33, 95% CI 0.01 to 8.00, P = 0.50, and RR 0.33, 95% CI 0.01 to 7.72, P = 0.49; 142 participants; low-certainty evidence); recurrent events (RR 0.41, 95% CI 0.02 to 8.84, P = 0.57; 18 participants; very low-certainty evidence); incidence of other type of stroke (two studies, not pooled due to different type of index stroke, RR 6.11, 95% CI 0.33 to 111.71, P = 0.22, and RR 0.63, 95% CI 0.25 to 1.58, P = 0.32; 58 participants; very low-certainty evidence); and quality of life (physical component, MD -2.31, 95% CI -4.81 to 0.19, P = 0.07, and mental component, MD -2.16, 95% CI -5.91 to 1.59, P = 0.26; 1 study; 102 participants; low-certainty evidence). Adverse events were reported by two studies (57 participants; very low-certainty evidence), one trial reporting extracranial haemorrhage (RR 0.25, 95% CI 0.04 to 1.73, P = 0.16) and the other one reporting bleeding complications (RR 0.32, 95% CI 0.01 to 7.35, P = 0.47). Longer follow-up (more than three months) One small trial assessed functional outcome with both the Barthel Index for activities of daily living (MD 7.09, 95% CI -5.16 to 19.34, P = 0.26), and the Rivermead Mobility Index for mobility (MD 1.30, 95% CI -1.31 to 3.91, P = 0.33) (52 participants; very low-certainty evidence). We carried out meta-analysis for vascular-related death (RR 1.02, 95% CI 0.78 to 1.35, P = 0.86; 5 studies; 2237 participants; low-certainty evidence) and fatal recurrent events (RR 0.69, 95% CI 0.31 to 1.55, P = 0.37; 3 studies; 1819 participants; low-certainty evidence). We found no evidence of an effect of the intervention for mood (MD 1.00, 95% CI -2.07 to 4.07, P = 0.61; 1 study; 14 participants; low-certainty evidence). Incidence of other type of stroke and quality of life were not reported. Adverse events (all combined) were reported by only one study (RR 0.94, 95% CI 0.56 to 1.58, P = 0.82; 1455 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

We are very uncertain of the effect of marine-derived n-3 PUFAs therapy on functional outcomes and dependence after stroke as there is insufficient high-certainty evidence. More well-designed RCTs are needed, specifically in acute stroke, to determine the efficacy and safety of the intervention. Studies assessing functional outcome might consider starting the intervention as early as possible after the event, as well as using standardised, clinically relevant measures for functional outcomes, such as the modified Rankin Scale. Optimal doses remain to be determined; delivery forms (type of lipid carriers) and mode of administration (ingestion or injection) also need further consideration.

Strengthening national nutrition research: rationale and options for a new coordinated federal research effort and authority

BACKGROUND

The US faces remarkable food and nutrition challenges. A new federal effort to strengthen and coordinate nutrition research could rapidly generate the evidence base needed to address these multiple national challenges. However, the relevant characteristics of such an effort have been uncertain.

OBJECTIVES

Our aim was to provide an objective, informative summary of 1) the mounting diet-related health burdens facing our nation and corresponding economic, health equity, national security, and sustainability implications; 2) the current federal nutrition research landscape and existing mechanisms for its coordination; 3) the opportunities for and potential impact of new fundamental, clinical, public health, food and agricultural, and translational scientific discoveries; and 4) the various options for further strengthening and coordinating federal nutrition research, including corresponding advantages, disadvantages, and potential executive and legislative considerations.

METHODS

We reviewed government and other published documents on federal nutrition research; held various discussions with expert groups, advocacy organizations, and scientific societies; and held in-person or phone meetings with >50 federal staff in executive and legislative roles, as well as with a variety of other stakeholders in academic, industry, and nongovernment organizations.

RESULTS

Stark national nutrition challenges were identified. More Americans are sick than are healthy, largely from rising diet-related illnesses. These conditions create tremendous strains on productivity, health care costs, health disparities, government budgets, US economic competitiveness, and military readiness. The coronavirus disease 2019 (COVID-19) outbreak has further laid bare these strains, including food insecurity, major diet-related comorbidities for poor outcomes from COVID-19 such as diabetes, hypertension, and obesity, and insufficient surveillance on and coordination of our food system. More than 10 federal departments and agencies currently invest in critical nutrition research, yet with relatively flat investments over several decades. Coordination also remains suboptimal, documented by multiple governmental reports over 50 years. Greater harmonization and expansion of federal investment in nutrition science, not a silo-ing or rearrangement of existing investments, has tremendous potential to generate new discoveries to improve and sustain the health of all Americans. Two identified key strategies to achieve this were as follows: 1) a new authority for robust cross-governmental coordination of nutrition research and other nutrition-related policy and 2) strengthened authority, investment, and coordination for nutrition research within the NIH. These strategies were found to be complementary, together catalyzing important new science, partnerships, coordination, and returns on investment. Additional complementary actions to accelerate federal nutrition research were identified at the USDA.

CONCLUSIONS

The need and opportunities for strengthened federal nutrition research are clear, with specific identified options to help create the new leadership, strategic planning, coordination, and investment the nation requires to address the multiple nutrition-related challenges and grasp the opportunities before us.

Lipid-modifying effects of krill oil vs fish oil: a network meta-analysis

CONTEXT

Krill oil is a good source of n-3 phospholipids and has greater bioavailability than fish oil, which contains n-3 triglycerides. However, it is unclear whether krill oil affects circulating lipid concentrations more beneficially than fish oil.

OBJECTIVE

A network meta-analysis was conducted to compare the lipid-modifying effects of krill oil and fish oil.

DATA SOURCES

PubMed and Embase databases were searched.

STUDY SELECTION

A total of 64 randomized controlled trials that determined the lipid-modifying effects of krill oil or fish oil were selected.

DATA EXTRACTION

The MetaXL program was used for meta-analysis. A subgroup analysis and a network meta-regression were conducted to investigate the dose-response effect of the n-3 fatty acid content of fish oil and krill oil.

RESULTS

Krill oil was associated with significantly lower triglyceride levels than control supplements (weighted mean difference [WMD] -23.26 [95%CI, -38.84 to -7.69]). However, the net differences in triglycerides (WMD -4.07 [95%CI, -15.22 to 7.08]), low-density lipoprotein cholesterol (WMD 3.01 [95%CI, -5.49 to 11.51]), high-density lipoprotein cholesterol (WMD 1.37 [95%CI, -3.73 to 6.48]), and total cholesterol (WMD 1.69 [95%CI, -6.62 to 10.01]) were not significantly different between the krill oil and fish oil groups. One gram of n-3 fatty acids contained in fish oil and krill oil lowered median triglycerides by 8.971 mg/dL (95% credible interval [CrI], 2.27 to 14.04) and 9.838 mg/dL (95%CrI, 0.72 to 19.40), respectively.

CONCLUSIONS

The lipid-modifying effects of krill oil and fish oil do not differ. The reduction in triglycerides depends on the dose of n-3 fatty acids consumed.

Marine-derived n-3 fatty acids therapy for stroke

BACKGROUND

Currently, with stroke burden increasing, there is a need to explore therapeutic options that ameliorate the acute insult. There is substantial evidence of a neuroprotective effect of marine-derived n-3 polyunsaturated fatty acids (PUFAs) in experimental stroke, leading to a better functional outcome.

OBJECTIVES

To assess the effects of administration of marine-derived n-3 PUFAs on functional outcomes and dependence in people with stroke.Our secondary outcomes were vascular-related death, recurrent events, incidence of other type of stroke, adverse events, quality of life, and mood.

SEARCH METHODS

We searched the Cochrane Stroke Group trials register (6 August 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 1, January 2019), MEDLINE Ovid (from 1948 to 6 August 2018), Embase Ovid (from 1980 to 6 August 2018), CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; from 1982 to 6 August 2018), Science Citation Index Expanded ‒ Web of Science (SCI-EXPANDED), Conference Proceedings Citation Index-Science - Web of Science (CPCI-S), and BIOSIS Citation Index. We also searched ongoing trial registers, reference lists, relevant systematic reviews, and used the Science Citation Index Reference Search.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing marine-derived n-3 PUFAs to placebo or open control (no placebo) in people with a history of stroke or transient ischaemic attack (TIA), or both.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected trials for inclusion, extracted data, assessed risk of bias, and used the GRADE approach to assess the quality of the body of evidence. We contacted study authors for clarification and additional information on stroke/TIA participants. We conducted random-effects meta-analysis or narrative synthesis, as appropriate. The primary outcome was efficacy (functional outcome) assessed using a validated scale e.g. Glasgow Outcome Scale Extended (GOSE) dichotomised into poor or good clinical outcome, Barthel Index (higher score is better; scale from 0 to 100) or Rivermead Mobility Index (higher score is better; scale from 0 to 15).

MAIN RESULTS

We included 29 RCTs; nine of them provided outcome data (3339 participants). Only one study included participants in the acute phase of stroke (haemorrhagic). Doses of marine-derived n-3 PUFAs ranged from 400 mg/day to 3300 mg/day. Risk of bias was generally low or unclear in most trials, with a higher risk of bias in smaller studies. We assessed results separately for short (up to three months) and longer (more than three months) follow-up studies.Short follow-up (up to three months)Functional outcome was reported in only one pilot study as poor clinical outcome assessed with GOSE (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.36 to 1.68; 40 participants; very low quality evidence). Mood (assessed with GHQ-30, lower score better), was reported by only one study and favoured control (mean difference (MD) 1.41, 95% CI 0.07 to 2.75; 102 participants; low-quality evidence).We found no evidence of an effect of the intervention for the remainder of the secondary outcomes: vascular-related death (two studies, not pooled due to differences in population, RR 0.33, 95% CI 0.01 to 8.00, and RR 0.33, 95% CI 0.01 to 7.72; 142 participants; low-quality evidence); recurrent events (RR 0.41, 95% CI 0.02 to 8.84; 18 participants; very low quality evidence); incidence of other type of stroke (two studies, not pooled due to different type of index stroke, RR 6.11, 95% CI 0.33 to 111.71, and RR 0.63, 95% CI 0.25 to 1.58; 58 participants; very low quality evidence); and quality of life (physical component mean difference (MD) -2.31, 95% CI -4.81 to 0.19, and mental component MD -2.16, 95% CI -5.91 to 1.59; one study; 102 participants; low-quality evidence).Adverse events were reported by two studies (57 participants; very low quality evidence), one trial reporting extracranial haemorrhage (RR 0.25, 95% CI 0.04 to 1.73) and the other one reporting bleeding complications (RR 0.32, 95% CI 0.01 to 7.35).Longer follow-up (more than three months)One small trial assessed functional outcome with both Barthel Index (MD 7.09, 95% CI -5.16 to 19.34) for activities of daily living, and Rivermead Mobility Index (MD 1.30, 95% CI -1.31 to 3.91) for mobility (52 participants; very low quality evidence). We carried out meta-analysis for vascular-related death (RR 1.02, 95% CI 0.78 to 1.35; five studies; 2237 participants; low-quality evidence) and fatal recurrent events (RR 0.69, 95% CI 0.31 to 1.55; three studies; 1819 participants; low-quality evidence).We found no evidence of an effect of the intervention for mood (MD 1.00, 95% CI -2.07 to 4.07; one study; 14 participants; low-quality evidence). Incidence of other type of stroke and quality of life were not reported.Adverse events (all combined) were reported by only one study (RR 0.94, 95% CI 0.56 to 1.58; 1455 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

We are very uncertain of the effect of marine-derived n-3 PUFAs therapy on functional outcomes and dependence after stroke as there is insufficient high-quality evidence. More well-designed RCTs are needed, specifically in acute stroke, to determine the efficacy and safety of the intervention.Studies assessing functionality might consider starting the intervention as early as possible after the event, as well as using standardised clinically-relevant measures for functional outcomes, such as the modified Rankin Scale. Optimal doses remain to be determined; delivery forms (type of lipid carriers) and mode of administration (ingestion or injection) also need further consideration.

N-3 fatty acids for prevention of cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death in the USA. A diet enriched with n-3 fatty acids (FA) has been reported to play an important role in preventing the development of CVD. Prior studies have demonstrated beneficial effects of n-3 FA on hypertriglyceridemia, blood pressure, inflammation, endothelial function, and platelet function. However, data on the relation of n-3 FA consumption with CVD risk remain inconsistent. This paper reviews current evidence on the effects of n-3 FA on CVD, CVD risk factors, and potential biologic mechanisms. Last, we discuss major limitations of currently available data and future directions in the field.

Protection from procedural myocardial injury by omega-3 polyunsaturated fatty acids (PUFAs): is related with lower levels of creatine kinase-MB (CK-MB) and troponin I?

OBJECTIVE

This study sought to investigate the effect of omega-3 polyunsaturated fatty acids (PUFAs) on cardiac biomarkers, CK-MB, and troponin I in patients undergoing PCI.

BACKGROUND

Restenosis remains as a major long-term complication following percutaneous coronary intervention (PCI). It appears that there is strong relationship between post-PCI creatine kinase-MB (CK-MB) and troponin I elevation and cardiovascular events after PCI.

METHODS

In this randomized clinical trial, a total of 90 patients planned to undergo PCI were randomly assigned into two groups: Group A-receiving omega-3 PUFAs (3 g, 12 h before PCI) plus standard treatment (n = 43) and Group B-control group, receiving only standard therapy (n = 47). Standard treatment included aspirin 325 mg and clopidogrel 600 mg loading dose. The plasma CK-MB level was measured before the procedure (baseline), at 8 and 24 h after PCI. The plasma troponin I was measured at baseline and 24 h after PCI.

RESULTS

In comparison with control, omega-3 PUFAs could significantly reduce the level of CK-MB in 8 (P = 0.001) and 24 h (P = 0.012) after its prescription in the omega-3 PUFAs group. Omega-3 PUFAs could not significantly decrease troponin I.

CONCLUSION

Our results revealed that omega-3 PUFAs can be considered as a safe adjunctive medication to the standard regimen before PCI for the aim of decreasing cardiovascular event after PCI.

Omega-3 polyunsaturated acids and cardiovascular disease: notable ethnic differences or unfulfilled promise?

The consumption of long chain omega-3 polyunsaturated acids (PUFA) is considered to protect against cardiovascular disease and promote longevity following a heart attack. Historically, research in this area was fuelled by compelling reports of the cardiovascular benefits of omega-3 PUFA in select populations and cultures. More recent studies, in wider populations, suggest discordant findings: differences that are difficult to reconcile as the mechanism of action of omega-3 PUFA are poorly understood. As such, the use of this 'natural treatment' for cardiovascular disease is increasingly controversial, and potentially one of unfulfilled promise. To what extent does ethnicity influence the impact that omega-3 PUFA have on cardiovascular disease and its associated complications? We were interested to review the benefits of omega-3 PUFA in the management of cardiovascular risk amongst diverse ethnic groups. Using a systematic review of literature relating to omega-3 PUFA and cardiovascular disease, we found ethnicity to be a factor that accounts for inconsistency between studies. Some of the effects of omega-3 PUFA are limited to cultures with a very high omega-3 intake, and in turn, ethnicity moderates the efficiency with which PUFA are derived from the diet. Moreover, omega-3 PUFA are an important health care intervention in the current climate of globalization, where supplementation is likely to give protection to cultural groups undergoing dietary transition. Future epidemiological research into the efficacy of omega-3 PUFA in cardiovascular disease should consider the influence of ethnicity.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Do vegetarians have to eat fish for optimal cardiovascular protection?

Interest in the cardiovascular protective effects of n-3 (omega-3) fatty acids has continued to evolve during the past 35 y since the original research describing the low cardiovascular event rate in Greenland Inuit was published by Dyerberg et al. Numerous in vitro experiments have shown that n-3 fatty acids may confer this benefit by several mechanisms: they are antiinflammatory, antithrombotic, and antiarrhythmic. The n-3 fatty acids that have received the most attention are those that are derived from a fish source: namely, the longer-chain n-3 fatty acids eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). More limited data are available on the cardiovascular effects of n-3 fatty acids derived from plants such as alpha-linolenic acid (ALA; 18:3n-3). Observational data suggest that diets rich in EPA, DHA, or ALA do reduce cardiovascular events, including myocardial infarction and sudden cardiac death; however, randomized controlled trial data are somewhat less clear. Several recent meta-analyses have suggested that dietary supplementation with EPA and DHA does not provide additive cardiovascular protection beyond standard care, but the heterogeneity of included studies may reduce the validity of their conclusions. No data exist on the potential therapeutic benefit of EPA, DHA, or ALA supplementation on those individuals who already consume a vegetarian diet. Overall, there is insufficient evidence to recommend n-3 fatty acid supplementation for the purposes of cardiovascular protection; however, ongoing studies such as the Alpha Omega Trial may provide further information.

Generic and product-specific health claim processes for functional foods across global jurisdictions

Worldwide consumer interest in functional foods and their potential health benefits has been increasing over the past 10 y. To respond to this interest, regulatory bodies have developed guidelines for assessing health claims on functional foods. The objective of this article is to investigate the type and amount of evidence needed in various jurisdictions on a worldwide basis to substantiate both generic and product-specific health claims. Two types of health claims were examined using separate case studies. Analysis of generic health claims was highlighted by (n-3) fatty acids and their relation to heart health; whereas examination of product-specific health claims was conducted using probiotics and their association with gastrointestinal well-being. Results showed a common core for use of convincing high-quality human data, especially in the form of randomized controlled trials (RCT), but there was significant variability in the type and amount of scientific evidence needed to substantiate health claims, both generic and product specific, across different jurisdictions. Product-specific claims tended to use human RCT as the main basis for claims, whereas generic claims tended to base their statements on a wider spectrum of literature.

Omega-3 fatty acids, atherogenesis, and endothelial activation

Omega-3 or n-3 polyunsaturated fatty acids (PUFAs) display a variety of beneficial effects on various organ systems and diseases. Evidence for cardiovascular protective effects was among the first reasons for biomedical interest in these fats. Following these initial reports, evidence has continued to emerge demonstrating the cardioprotective effects of n-3 PUFAs and elucidating the underlying biological mechanisms. Decreased atherogenesis is currently thought to account at least in part for cardiovascular protection by n-3 PUFAs. We summarise the evidence for such effects and the putative mechanisms involved.

Expert opinion: omega-3 fatty acids and bleeding-cause for concern?

Omega-3 fatty acid ethyl esters have well-known triglyceride-lowering properties and were shown >30 years ago to inhibit platelet function. With the recent US Food and Drug Administration (FDA) approval of these agents for treating severe triglyceride elevations, concerns about excess bleeding naturally arise. However, an objective assessment of the evidence for clinically significant bleeding reveals that such concerns are unfounded. As such, the benefits of triglyceride lowering with omega-3 fatty acids more than outweigh any theoretical risks for increased bleeding.

Antiatherogenic effects of n-3 fatty acids - evidence and mechanisms

N-3 (omega-3) (polyunsaturated) fatty acids are thought to display a variety of beneficial effects for human health. Clues to the occurrence of cardiovascular protective effects have been, however, the spur for the first biomedical interest in these compounds, and are the best documented. Historically, the epidemiologic association between dietary consumption of n-3 fatty acids and cardiovascular protection was first suggested by Bang and Dyerberg, who identified the high consumption of fish, and therefore, of fish oil-derived n-3 fatty acids, as the likely explanation for the strikingly low rate of coronary heart disease events reported in the Inuit population. Since their initial reports, research has proceeded in parallel to provide further evidence for their cardioprotection and to understand underlying mechanisms. Decreased atherogenesis is currently thought to be a part of the cardiovascular protection by n-3 fatty acids. This article summarizes the evidence for such a claim and the mechanisms putatively involved.

Effects of omega-3 fatty acids on serum markers of cardiovascular disease risk: A systematic review

Greater fish oil consumption has been associated with reduced CVD risk, although the mechanisms are unclear. Plant-source oil omega-3 fatty acids (ALA) have also been studied regarding their cardiovascular effect. We conducted a systematic review of randomized controlled trials that evaluated the effect of consumption of fish oil and ALA on commonly measured serum CVD risk factors, performing meta-analyses when appropriate. Combining 21 trials evaluating lipid outcomes, fish oil consumption resulted in a summary net change in triglycerides of -27 (95% CI -33, -20)mg/dL, in HDL cholesterol of +1.6 (95% CI +0.8, +2.3)mg/dL, and in LDL cholesterol of +6 (95% CI +3, +8)mg/dL. There was no effect of fish oil on total cholesterol. Across studies, higher fish oil dose and higher baseline levels were associated with greater reductions in serum triglycerides. Overall, the 27 fish oil trials evaluating Hgb A(1c) or FBS found small non-significant net increases compared to control oils. Five studies of ALA were inconsistent in their effects on lipids, Hgb A(1c) or FBS. Four studies investigating the effects of omega-3 fatty acids on hs-CRP were also inconsistent and non-significant. The evidence supports a dose-dependent beneficial effect of fish oil on serum triglycerides, particularly among people with more elevated levels. Fish oil consumption also modestly improves HDL cholesterol, increases LDL cholesterol levels, but does not appear to adversely affect glucose homeostasis. The evidence regarding the effects of omega-3 fatty acids on hs-CRP is inconclusive, as are data on ALA.

n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review

Studies on the relation between dietary n-3 fatty acids (FAs) and cardiovascular disease vary in quality, and the results are inconsistent. A systematic review of the literature on the effects of n-3 FAs (consumed as fish or fish oils rich in eicosapentaenoic acid and docosahexaenoic acid or as alpha-linolenic acid) on cardiovascular disease outcomes and adverse events was conducted. Studies from MEDLINE and other sources that were of > or =1 y in duration and that reported estimates of fish or n-3 FA intakes and cardiovascular disease outcomes were included. Secondary prevention was addressed in 14 randomized controlled trials (RCTs) of fish-oil supplements or of diets high in n-3 FAs and in 1 prospective cohort study. Most trials reported that fish oil significantly reduced all-cause mortality, myocardial infarction, cardiac and sudden death, or stroke. Primary prevention of cardiovascular disease was reported in 1 RCT, in 25 prospective cohort studies, and in 7 case-control studies. No significant effect on overall deaths was reported in 3 RCTs that evaluated the effects of fish oil in patients with implantable cardioverter defibrillators. Most cohort studies reported that fish consumption was associated with lower rates of all-cause mortality and adverse cardiac outcomes. The effects on stroke were inconsistent. Evidence suggests that increased consumption of n-3 FAs from fish or fish-oil supplements, but not of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. The evidence for the benefits of fish oil is stronger in secondary- than in primary-prevention settings. Adverse effects appear to be minor.

Effects of omega-3 fatty acids on coronary restenosis, intima–media thickness, and exercise tolerance: A systematic review

Greater omega-3 fatty acid consumption is associated with reduced cardiovascular disease risk. Though the mechanisms of their effect are unclear, they may involve lesion formation and heart function. We conducted a systematic review of the clinical literature on the effect of omega-3 fatty acids on measures of vascular structure and function. We included studies that assessed fish and plant sources of omega-3 fatty acids on coronary artery restenosis after angioplasty, carotid IMT, and exercise capacity. Compared to placebo, the summary risk ratio of coronary artery restenosis with fish oil is 0.87 (95% CI 0.73, 1.05) across 12 randomized controlled trials. Two prospective studies reported increased carotid IMT, whereas two cross-sectional studies reported a reduction of IMT, with fish, fish oil or ALA consumption. Three randomized trials and three uncontrolled studies reported small non-significant improvements in exercise capacity with fish oil. Overall, little or no effect of fish oil was found for a variety of markers of cardiovascular disease risk. There are insufficient studies to draw conclusions about the effect of ALA. The dearth of long term data on fish consumption or omega-3 fatty acid supplementation on measures of cardiovascular disease risk severely limits our ability to draw definitive conclusions at this time.

Antiarrhythmic Mechanisms of n-3 PUFA and the Results of the GISSI-Prevenzione Trial

The purpose of this paper is twofold: on the one hand, to confirm the positive results on n-3 PUFA from the overall results Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GlSSI)-Prevenzione trial; on the other, to summarize and describe how the results of an important trial can help generate hypotheses either on mechanisms of action or on differential results in particular subgroups of patients, as well as test the pathophysiological hypotheses that have accompanied in the years the story of the hypothesized mechanisms of action of a drug. GISSI-Prevenzione was conceived as a pragmatic population trial on patients with recent myocardial infarction and it was conducted in the framework of the Italian public health system. In GISSI-Prevenzione, 11,323 patients were enrolled in a clinical trial aimed at testing the effectiveness of n-3 polyunsaturated fatty acids (PUFA) and vitamin E. Patients were invited to follow Mediterranean dietary habits, and were treated with up-to-date preventive pharmacological interventions. Long-term n-3 PUFA at 1 g daily, but not vitamin E at 300 mg daily, was beneficial for death and for combined death, non-fatal myocardial infarction, and stroke. All the benefit, however, was attributable to the decrease in risk for overall (-20%), cardiovascular (-30%), and sudden death (-45%). At variance from the orientation of a scientific scenario largely dominated by the "cholesterol-heart hypothesis", GISSI-Prevenzione results indicate n-3 PUFA (virtually devoid of any cholesterol-lowering effect) as a relevant pharmacological treatment for secondary prevention after myocardial infarction.

Starc II, a multicenter randomized placebo-controlled double-blind clinical trial of trapidil for 1-year clinical events and angiographic restenosis reduction after coronary angioplasty and stenting

The objective of this study was to investigate the effect of trapidil 200 mg t.i.d. in preventing the occurrence of death, of myocardial infarction and the need for repeat revascularization at 12 months after balloon PTCA with or without stenting. Coronary restenosis after stenting is still a major drawback of percutaneous coronary interventions (PCI) for 30-40% of patients. Trapidil has been shown to prevent restenosis after PTCA. Eligible patients were randomized to placebo or oral trapidil 200 mg t.i.d. at least 48 hr before PCI and continuing 6 months after a successful balloon angioplasty or stent implantation. Aspirin was given to all patients, and ticlopidine 250 mg b.i.d. to those who received a stent for 4 weeks. In a randomized subgroup of 216 patients, quantitative coronary angiography was performed also at 6-month follow-up. Out of the 933 patients enrolled, primary endpoint incidence was 20.3% in trapidil and 18.0% in placebo (P = 0.37). When recurrence or deterioration of angina was added to the combined endpoint, incidence was 27.4% in trapidil and 23.0% in placebo (P = 0.12). Restenosis rate in patients with 6-month angiography was 25.0% in trapidil arm vs. 30.1% in placebo (P = 0.43). Stent restenosis rate was similar in patients randomized to trapidil or placebo (30.2% vs. 23.8%, respectively; P = 0.44), while in patients treated with balloon angioplasty, it was lower in trapidil (17.1%) than in placebo (40.0%; P = 0.03). Oral trapidil 200 mg t.i.d. for 6 months in addition to aspirin did not influence the occurrence of major cardiac events after coronary angioplasty with or without stenting. In a prespecified subgroup of 191 patients treated with balloon angioplasty only, trapidil reduced angiographic restenosis.

Effects of omega-3 fatty acids on cytokines and adhesion molecules

The dietary intake of omega-3 (n-3) polyunsaturated fatty acids has emerged, over the past 20 years, as an important way to modify cardiovascular risk. This likely occurs through beneficial effects at all stages in the natural history of vascular disease, from the inception of atherosclerotic lesions, to their growth and acute complications (plaque rupture in most instances), up to protection of myocardium from the consequences of ensuing acute myocardial ischemia. This review specifically focuses on the modulating effects of n-3 fatty acids on biologic events involved in early atherogenesis, including important properties of these natural substances on endothelial expression of adhesion molecules and cytokines, processes collectively denoted as "endothelial activation." By decreasing the endothelial responsiveness to proinflammatory and proatherogenic stimuli, n-3 fatty acids act on molecular events not targeted by any other drugs or interventions, and thereby complementary to those of already implemented pharmacologic treatments.

Omega 3 fatty acids for prevention and treatment of cardiovascular disease

BACKGROUND

It has been suggested that omega 3 (W3, n-3 or omega-3) fats from oily fish and plants are beneficial to health.

OBJECTIVES

To assess whether dietary or supplemental omega 3 fatty acids alter total mortality, cardiovascular events or cancers using both RCT and cohort studies.

SEARCH STRATEGY

Five databases including CENTRAL, MEDLINE and EMBASE were searched to February 2002. No language restrictions were applied. Bibliographies were checked and authors contacted.

SELECTION CRITERIA

RCTs were included where omega 3 intake or advice was randomly allocated and unconfounded, and study duration was at least six months. Cohorts were included where a cohort was followed up for at least six months and omega 3 intake estimated.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion, data extracted and quality assessed independently in duplicate. Random effects meta-analysis was performed separately for RCT and cohort data.

MAIN RESULTS

Forty eight randomised controlled trials (36,913 participants) and 41 cohort analyses were included. Pooled trial results did not show a reduction in the risk of total mortality or combined cardiovascular events in those taking additional omega 3 fats (with significant statistical heterogeneity). Sensitivity analysis, retaining only studies at low risk of bias, reduced heterogeneity and again suggested no significant effect of omega 3 fats. Restricting analysis to trials increasing fish-based omega 3 fats, or those increasing short chain omega 3s, did not suggest significant effects on mortality or cardiovascular events in either group. Subgroup analysis by dietary advice or supplementation, baseline risk of CVD or omega 3 dose suggested no clear effects of these factors on primary outcomes. Neither RCTs nor cohorts suggested increased relative risk of cancers with higher omega 3 intake but estimates were imprecise so a clinically important effect could not be excluded.

REVIEWERS' CONCLUSIONS

It is not clear that dietary or supplemental omega 3 fats alter total mortality, combined cardiovascular events or cancers in people with, or at high risk of, cardiovascular disease or in the general population. There is no evidence we should advise people to stop taking rich sources of omega 3 fats, but further high quality trials are needed to confirm suggestions of a protective effect of omega 3 fats on cardiovascular health. There is no clear evidence that omega 3 fats differ in effectiveness according to fish or plant sources, dietary or supplemental sources, dose or presence of placebo.

Addition of cytochalasin D to a biocompatible oil stent coating inhibits intimal hyperplasia in a porcine coronary model

BACKGROUND

Polymer-based, drug-eluting stents, are currently under extensive investigation in the conquest against in-stent restenosis. Concern remains, however, about potential long-term lack of biocompatibility of the polymers used in these studies. Therefore, this study aimed to evaluate in porcine coronary arteries (1) the in vivo biocompatibility of a new natural, eicosapentaenoic acid oil stent-coating and (2) the efficacy of this coating in preventing in-stent restenosis when cytochalasin D--an inhibitor of actin filament formation, that interferes with cell proliferation and migration--was added.

METHODS AND RESULTS

To assess in vivo biocompatibility of the oil coating, 15 bare and 15 oil-coated stents were randomly deployed in coronary arteries of 15 pigs. No difference in tissue response, regarding inflammation or proliferation, was seen between both groups at five days or at four weeks follow-up. To evaluate the efficacy of the coating in preventing in-stent restenosis by adding a potential anti-restenotic drug, stents were dip-coated in 20 mg cytochalasin D/ml oil solution, resulting in 93 +/- 18 microg cytochalasin D/stent load (n = 3). In vitro drug release studies showed sustained release up to four weeks. Next, 11 oil-coated and 11 cytochalasin D-loaded stents were randomly implanted in coronary arteries of 11 pigs. At four weeks, a 39% decrease in neointimal hyperplasia (p < 0.05, ANCOVA, with injury as covariate) was found in cytochalasin D-loaded stents compared to oil-coated stents.

CONCLUSIONS

This new natural oil stent-coating shows excellent biocompatibility to vascular tissue. Local cytochalasin D delivery from this stent-platform significantly inhibits neointimal hyperplasia in a porcine coronary model.