Effects of fish oil rich in eicosapentaenoic acid on serum lipid in hyperlipidemic hemodialysis patients

Effect of Dietary Fish Oil on Lipid Abnormalities in Patients on Continuous Ambulatory Peritoneal Dialysis

Fifteen patients receiving continuous ambulatory peritoneal dialysis (CAPD) were given 10 mL of a dietary fish oil rich in omega-3 fatty acids (MaxEPA) b.i.d. for eight weeks without other dietary manipulation. Fasting lipids, vitamins A and E, and glucose were measured at 0, 4, and 8 weeks, and again at 4 and 8 weeks after the cessation of treatment.

Basal serum triglyceride concentrations were raised, and fell by 29% (p < 0.005) with treatment, returning to baseline values over the washout period. The fall in triglyceride during treatment correlated with the initial value (As = 0.57; p < 0.05). Total, HDL and LDL cholesterol, apolipoprotein A, vitamin A, glucose, lean body mass, and dietary fat/CHO intake were unchanged throughout. Apolipoprotein B concentrations tended to rise during the first half of treatment but fell thereafter. Vitamin E concentrations rose significantly during supplementation and fell after withdrawal (p < 0.001 for both).

Supplementation with dietary fish oil significantly reduced hypertriglyceridemia. Its long-term use might be accompanied by beneficial effects on the excess cardiovascular morbidity seen in patients on CAPD.

Effect of Hypertriglyceridemia Correction by Omega-3 Fatty Acids on Peritoneal Transport in Continuous Ambulatory Peritoneal Dialysis Patients

Lipid abnormalities, both hypercholesterolemia and particularly hypertriglyceridemia (hyperTg), are common in long-term continuous ambulatory peritoneal dialysis (CAPO) patients. Hyperviscosity and rheological alterations have been proposed as major hemodynamic problems in hyperTg patients.

The aim of this study was to evaluate whether a hyperTg correction by employing omega-3 fatty acids (ω-3) affects peritoneal transport.

Six hyperTg (>700 mg/dL) CAPO patients were treated with 2–3 g/day of ω-3 until normal Tg values were achieved. The assessment of peritoneal dialysis efficacy was performed by evaluating the peritoneal equilibration test (PET) before ω-3 supplementation, when normal Tg levels were reached, and 3 weeks after stopping therapy when hyperTg returned.

When normal Tg levels were reached, a small but significant Improvement of urea and creatinine O/P was noted: 0.85±0.05 versus 0.93±0.03 (p<0.05) and 0.78±0.03 versus 0.86±0.05 (p<0.05), respectively, with negative correlation between O/P of urea and Tg.

These preliminary data demonstrate that a hyperTg correction with ω-3 may Induce an Increase In peritoneal transport of small molecules in CAPO.

Blood Fatty Acid Status and Clinical Outcomes in Dialysis Patients: A Systematic Review

Blood fatty acids (FAs) are derived from endogenous and dietary routes. Metabolic abnormalities from kidney dysfunction, as well as cross-cultural dietary habits, may alter the FA profile of dialysis patients (DP), leading to detrimental clinical outcomes. Therefore, we aimed to (i) summarize FA status of DP from different countries, (ii) compare blood FA composition between healthy controls and DP, and (iii) evaluate FA profile and clinical endpoints in DP. Fifty-three articles from 1980 onwards, reporting FA profile in hemodialysis and peritoneal DP, were identified from PubMed, Embase, and the Cochrane library. Studies on pediatric, predialysis chronic kidney disease, acute kidney injury, and transplant patients were excluded. Moderate to high levels of n-3 polyunsaturated fatty acids (PUFA) were reported in Japan, Korea, Denmark, and Sweden. Compared to healthy adults, DP had lower proportions of n-3 and n-6 PUFA, but higher proportion of monounsaturated fatty acids. Two studies reported inverse associations between n-3 PUFAs and risks of sudden cardiac death, while one reported eicosapentaenoic acid + docosahexaenoic acid)/arachidonic acid ratio was inversely associated with cardiovascular events. The relationship between all-cause mortality and blood FA composition in DP remained inconclusive. The current evidence highlights a critical role for essential FA in nutritional management of DP.

Eicosapentaenoic Acid as a Potential Therapeutic Approach to Reduce Cardiovascular Risk in Patients with End-Stage Renal Disease on Hemodialysis: A Review

Background

Patients with end-stage renal disease on hemodialysis have excess cardiovascular disease (CVD) burden with substantially increased CV event rates compared with the general population.

Summary

Traditional interventions that, according to standard clinical guidelines, reduce CV risk such as antihypertensive therapy, diet, exercise, and statins are not similarly effective in the hemodialysis population. This raises the question of whether additional risk factors, such as enhanced inflammation and oxidative stress, may drive the increased CVD burden in hemodialysis patients. Eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, is incorporated into the atherosclerotic plaque as well as membrane phospholipid bilayers and produces beneficial effects on inflammatory and oxidative mechanisms involved in atherosclerotic plaque formation and progression. EPA levels and the ratio of EPA to the omega-6 polyunsaturated fatty acid arachidonic acid (AA) are reduced in hemodialysis patients. Serum EPA levels have been inversely correlated with proinflammatory cytokines, and the EPA/AA ratio has been inversely associated with CV events in hemodialysis cohorts. Three recent studies involving over 800 hemodialysis patients and follow-up of 2-3 years suggest that EPA therapy may improve clinical outcomes in this patient population as evidenced by significant reductions in cardiovascular mortality, all-cause mortality, and/or CV events.

Key Messages

Further studies with high-purity EPA are warranted in patients on hemodialysis, especially given the fact that other interventions including antihypertensives, diet, exercise, and statins have not provided meaningful benefit.

Mitochondria: a new therapeutic target in chronic kidney disease

Cellular metabolic changes during chronic kidney disease (CKD) may induce higher production of oxygen radicals that play a significant role in the progression of renal damage and in the onset of important comorbidities. This condition seems to be in part related to dysfunctional mitochondria that cause an increased electron "leakage" from the respiratory chain during oxidative phosphorylation with a consequent generation of reactive oxygen species (ROS). ROS are highly active molecules that may oxidize proteins, lipids and nucleic acids with a consequent damage of cells and tissues. To mitigate this mitochondria-related functional impairment, a variety of agents (including endogenous and food derived antioxidants, natural plants extracts, mitochondria-targeted molecules) combined with conventional therapies could be employed. However, although the anti-oxidant properties of these substances are well known, their use in clinical practice has been only partially investigated. Additionally, for their correct utilization is extremely important to understand their effects, to identify the correct target of intervention and to minimize adverse effects. Therefore, in this manuscript, we reviewed the characteristics of the available mitochondria-targeted anti-oxidant compounds that could be employed routinely in our nephrology, internal medicine and renal transplant centers. Nevertheless, large clinical trials are needed to provide more definitive information about their use and to assess their overall efficacy or toxicity.

Patency in Arteriovenous Grafts in Hemodialysis Patients

Objective:

It is difficult to maintain a working access for patients on hemodialysis. Despite current Dialysis Outcome Quality Initiatives recommendations of “Fistula First,” not everyone qualifies for a fistula, and those patients undergoing the alternative treatment, a graft, can experience graft failure. This study examines factors associated with arteriovenous graft (AVG) patency.

Methods:

A retrospective analysis was completed for all the patients who had an AVG during 2005 to 2010. Data were collected from electronic medical records, including date of first and subsequent interventions, salvage technique (surgical vs percutaneous), medical comorbidities, and use of antiplatelet medications (aspirin and clopidogrel). Continuous variables were compared with 2 sample t tests, and categorical variables with chi-square/Fisher exact test. Logistic regression was used to determine the odds ratio for risk factors associated with patency. A P value of <.05 was considered significant. All analyses were done using SAS 9.2 (SAS Institute Inc, Cary, North Carolina).

Results:

A total of 193 unique patients had an AVG. Of the 193 patients, 64% were female, 83% were hypertensive, and 64% were diabetic. The locations of the grafts were 80% arm, 15% forearm, and 5% thigh. Configurations, including loop and straight, were 34% and 63%, respectively. Comorbidities were not associated with patency. Primary patency was not found to be different with respect to location and configuration of graft and type of intervention. Primary patency for patients taking only aspirin (n = 43) and only clopidogrel (n = 17) were significantly different from patients on a combination of aspirin and clopidogrel (n = 7), with a P = .0051 and P = .0447, respectively.

Conclusion:

Neither location nor configuration affects the primary patency of AVGs. Aspirin alone is not inferior to aspirin and clopidogrel. Further prospective studies may be warranted to establish a consensus regarding medications and patency with AVGs.

Adherence to fish oil intervention in patients with chronic kidney disease

OBJECTIVE

With growing recognition of the role of inflammation in the development of chronic and acute disease, fish oil is increasingly used as a therapeutic agent, but the nature of the intervention may pose barriers to adherence in clinical populations. Our objective was to investigate the feasibility of using a fish oil supplement in hemodialysis patients.

DESIGN

This was a nonrandomized intervention study.

SETTING

Eligible patients were recruited at the Hemodialysis Unit of Wesley Hospital, Brisbane, Queensland, Australia.

PATIENTS

The sample included 28 maintenance hemodialysis patients out of 43 eligible patients in the unit. Exclusion criteria included patients regularly taking a fish oil supplement at baseline, receiving hemodialysis for less than 3 months, or being unable to give informed consent.

INTERVENTION

Eicosapentaenoic acid (EPA) was administered at 2000 mg/day (4 capsules) for 12 weeks. Adherence was measured at baseline and weekly throughout the study according to changes in plasma EPA, and was further measured subjectively by self-report.

RESULTS

Twenty patients (74%) adhered to the prescription based on changes in plasma EPA, whereas an additional two patients self-reported good adherence. There was a positive relationship between fish oil intake and change in plasma EPA. Most patients did not report problems with taking the fish oil. Using the baseline data, it was not possible to characterize adherent patients.

CONCLUSIONS

Despite potential barriers, including the need to take a large number of prescribed medications already, 74% of hemodialysis patients adhered to the intervention. This study demonstrated the feasibility of using fish oil in a clinical population.

Review of the Effects of Omega-3 Supplementation in Dialysis Patients

Chronic dialysis patients experience a host of conditions that limit quality and length of life, and recent therapeutic strategies have had only modest success in ameliorating many of these problems. By mediating cell membrane function and structure and the synthesis of lipid mediators such as eicosanoids, omega-3 fatty acids may offer dialysis patients a host of therapeutic benefits. Omega-3 fatty acids are derived primarily from dietary sources, and cold-water fish is the main source of eicosapentanoic and docosahexanoic acids, the two major bioactive omega-3 fatty acids. Studies of omega-3 supplementation in dialysis patients describe salutary effects on triglyceride levels, dialysis access patency, and perhaps uremic pruritus and oxidative stress. In contrast, the putative hematologic, antihypertensive, anti-inflammatory, and antiarrhythmic effects are not as well documented. Adverse effects generally have been limited to gastrointestinal complaints. Unfortunately, the preponderance of published studies are characterized by suboptimal study design, small sample sizes, supraphysiologic omega-3 doses that may be difficult to consume for extended periods, little long-term follow-up, and a lack of confirmation of compliance. Not surprising, the 2005 National Kidney Foundation Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Cardiovascular Disease in Dialysis Patients recommend further research in this field. In summary, although preliminary data suggest that omega-3 fatty acids may have clinical benefits, formal recommendations encouraging omega-3 supplementation of dialysis patients are premature until long-term and adverse effects are better defined.

Reduced platelet serotonin content in rabbits with dietary hypercholesterolemia

Serotonin [5-hydroxytryptamine (5-HT)] has been implicated in platelet activation and vasoconstriction, two processes that contribute to arterial thrombosis in atherosclerotic diseases. In the present study, Japanese White rabbits fed 1% cholesterol for 5 weeks were used to investigate the response of hypercholesterolemic vascular arteries and platelets to 5-HT. Contractions of the thoracic aorta induced by 5-HT were comparable between the cholesterol-fed group and the age-matched control group. However, acetylcholine-induced vasodilation in arteries preconstricted with 5-HT was moderately but significantly attenuated in the cholesterol-fed rabbits. Platelet aggregation responses to 5-HT (0.1-3 micromol/l) in combination with epinephrine (5 micromol/l), adenosine diphosphate (ADP) (0.3-10 micromol/l), 9,11-dideoxy-9alpha,11alpha-methanoepoxy-prostaglandin F2alpha (U-46619) (1-30 micromol/l) or collagen (3 microg/ml) were significantly enhanced in cholesterol-fed rabbits. In contrast, platelet 5-HT content determined with a high-performance liquid chromatography-electrochemical detector (HPLC-ECD) was significantly decreased in cholesterol-fed rabbits. These results suggest a possible association among the endothelial dysfunction, platelet aggregation and platelet 5-HT content in rabbits with dietary hypercholesterolemia.

Elevated serum free fatty acid concentrations inhibit T lymphocyte signaling

Unbound cis-unsaturated free (i.e., nonesterified) fatty acids (FFA) inhibit T lymphocyte activation in vitro and therefore may exert immunosuppressive effects. However, in blood serum the major proportion of FFA is tightly bound to albumin, whereas unbound FFA are hardly detectable. Since serum FFA elevation occurs under pathological conditions like insulin resistance or cancer, which are often associated with a disturbed immune response, we addressed the question of whether increased serum FFA concentrations could affect T lymphocyte activation under in vivo conditions. Our studies revealed that 1) addition of pure long-chain cis-unsaturated FFA in the absence of albumin inhibited calcium response in cultured Jurkat T cells. 2) In healthy volunteers, serum FFA elevation by a lipid/heparin infusion, including predominantly unsaturated fatty acids, decreased calcium response of cultured T cells in contrast to studies without heparin. 3) Most notably, stepwise increasing serum FFA by lipid/heparin infusion also inhibited calcium response of simultaneously isolated autologous peripheral blood T lymphocytes as well as their CD4(+) and CD8(+) subsets. In conclusion, our data emphasize that serum FFA elevation is able to exert immunosuppressive effects in vivo.

Eicosapentanoic acid reduces plasma levels of remnant lipoproteins and prevents in vivo peroxidation of LDL in dialysis patients

Causative factors of uremia-associated atherosclerosis are complex. However, it is likely that atherogenic lipoproteins accumulated in plasma are involved. Remnant lipoproteins are atherogenic and are frequently observed in uremic plasma. LDL from uremic patients has been shown to be susceptible to in vitro peroxidation, suggesting that oxidized LDL (ox-LDL) could be excessively generated in those patients. No effective treatments to prevent accumulation of both atherogenic lipoproteins in dialysis patients have been published. Eicosapentanoic acid (EPA) may change synthesis and/or catabolism of remnant lipoproteins and increase stability of LDL to peroxidation by altering the fatty acid composition of lipoproteins. A prospective comparative study was conducted to assess the efficacy of EPA on metabolism of remnant lipoproteins and ox-LDL in dialysis patients using two new methods: an immunoaffinity gel separation for quantifying plasma remnant lipoproteins and an enzyme-linked immunosorbent assay for measuring plasma ox-LDL levels, a marker for in vivo LDL peroxidation. Twenty-two hemodialysis and 16 continuous ambulatory peritoneal dialysis patients with relatively high plasma levels of remnant lipoproteins and ox-LDL were randomized to either EPA or placebo. Highly purified EPA, in an ethyl-ester form (ethyl all-cis-5,8,11,14,17-icosapentanoate) with a purity greater than 91%, was administered at a dose of 1800 mg daily. Overall, 3 mo of treatment with EPA significantly reduced the levels of both remnant lipoproteins (52% reduction) and ox-LDL (38% reduction). Additionally, gel filtration chromatography of lipoproteins showed that EPA treatment concomitantly normalized other potential abnormalities in lipoproteins. Treatment compliance was good and no critical adverse effects were observed. In conclusion, EPA administration proved to be effective and safe treatment to decrease plasma remnant lipoproteins and prevent in vivo peroxidation of LDL in dialysis patients.

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.

Lipid-lowering therapy in patients with renal disease

A growing number of clinical trials have examined the effects of different lipid lowering strategies in patients with renal disease. We carried out a meta-analysis to compare and contrast the relative efficacy of various antilipemic therapies in different renal disease settings. Studies that investigated one or more therapies designed to lower serum lipids were combined using weighted multiple linear regression. The analysis adjusted treatment effects for differences in baseline lipid levels and possible placebo effects. The results showed that antilipemic therapies generally had similar effects on lipids in different renal disease settings. In nephrotic syndrome the greatest and most consistent reductions in low density lipoprotein cholesterol (LDL) were seen with 3-hydroxy-3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitors (regression coefficient with 95% confidence interval in mg/dl = -63, -79 to -46). Similar results were seen for LDL in renal transplant (-51, -57 to -45), renal insufficiency (-62, -82 to -42), hemodialysis (-65, -80 to -50) and continuous ambulatory peritoneal dialysis (CAPD) patients (-84, -104 to -64). Fibric acid analogues had less effect on LDL, but caused greater reductions in triglycerides: -132, -178 to -87, in nephrotic syndrome; -69, -93 to -45 in transplant: -107, -169 to -45 in renal insufficiency; -72, -120 to -24 in hemodialysis; and -96, -162 to -30 in CAPD. In general, the effects of diet and other therapies were less consistent. Despite possible limitations of this meta-analysis, the results provide a useful framework for choosing antilipemic therapy, and point to areas for future long-term studies examining the safety and efficacy of lipid lowering strategies in patients with renal disease.

Improvement of serum lipids and blood pressure during intervention with n-3 fatty acids was not associated with changes in insulin levels in subjects with combined hyperlipidaemia

OBJECTIVES

To investigate the effect of an omega-3 fatty acid concentrate K85 on serum lipids, lipoproteins, insulin metabolism and blood pressure in subjects with combined hyperlipidaemia.

DESIGN

After a run-in dietary period of 10 weeks, subjects were randomly allocated to receive either encapsulated K85 (n = 28) or corn oil (n = 29). The intervention was double-blind.

SETTING

An outpatient centre in Stavanger, Norway.

SUBJECTS

Fifty-seven of 141 individuals, who, after the run-in period continued to meet the inclusion criteria: serum triglycerides of > or = 2.0 mmol L-1 and total serum cholesterol of > or = 6.0 mmol L-1.

INTERVENTION

Encapsulated K85, containing 85% eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA), or corn oil, both administered in a daily dose of 4 g for 12 weeks.

MAIN OUTCOME MEASURES

Change in metabolic and haemodynamic parameters related to intervention.

RESULTS

Serum EPA and DHA increased significantly in the K85 group during the treatment period. The body-mass index remained unchanged. A 28% reduction in serum triglycerides was noted in the K85 group from the first 4 weeks. Total serum cholesterol was significantly reduced with both regimens. Serum high-density lipoprotein cholesterol increased significantly during the first 8 weeks in the K85 group. Significant reductions in systolic and diastolic blood pressures were noted in subjects on K85. The treatment did not affect serum glucose, plasma insulin and proinsulin levels. Insulin:glucose and proinsulin:glucose ratios remained unchanged.

CONCLUSIONS

The atherogenic risk profile was improved with K85 in subjects with combined hyperlipidaemia, but n-3 fatty acids supplementation did not affect glucose/insulin homeostasis.

n-3 fatty acids and renal diseases

There are numerous biologic rationales for the use of n-3 fatty acids in renal diseases, including a possible increase in the renal vasodilatory capacity by a rearrangement of renal prostanoid production, a reduction in the production of proinflammatory leukotrienes, a reduction in the transcapillary escape rate of albumin, and actions limiting cyclosporine-related nephrotoxicity. Studies of animal models of renal disease, mostly of immune-renal disease, support the idea of the possible usefulness of these compounds. The most promising areas of clinical investigation include the reduction of proteinuria in some chronic glomerular diseases, the treatment of immunoglobulin A nephropathy, and the prevention of cyclosporine-induced nephrotoxicity. However, the results of larger clinical studies, some of which are ongoing, are necessary to support the use of n-3 fatty acids in human renal diseases.

Disturbances of lipid metabolism in children with chronic renal failure

This review discusses the pathogenesis, clinical significance and current therapy of hyperlipoproteinaemia (HLP) in children with chronic renal failure. Uraemic dyslipidaemia, characterized by hypertriglyceridaemia and low high-density lipoprotein-cholesterol levels, is present in the majority patients with chronic renal failure. In addition, serum levels of total cholesterol, very low-density lipoprotein-cholesterol, low-density lipoportein-cholesterol and apolipoprotein B are frequently elevated. The pathophysiological mechanisms causing these disturbances are complex and mainly involve a diminished catabolism of triglyceride-rich lipoproteins. For unknown reasons and independent of other lipoproteins, serum levels of the highly atherogenic and thrombogenic lipoprotein(a) are also often elevated. HLP is an important factor in cardiovascular morbidity and mortality. In addition, dyslipidaemia may enhance progression of renal disease in patients with residual renal function. Therefore, treatment of HLP seems indicated in overtly hyperlipidaemic patients, but until there is more experience with lipid-lowering drugs in children, no safe recommendations for pharmacological treatment of HLP can be given. Dietary modifications can be recommended only to a limited extent.

[The effect of highly unsaturated fatty acids on the parameters of lipoprotein metabolism and rheology during their administration to patients undergoing chronic hemodialysis treatment]

Fifteen hemodialysis patients were treated with capsules of highly unsaturated fatty acids given in addition to their normal diet over a period of 6 months. At study start they received 12 capsules daily, each containing 105 mg eicosapentaenoic acid and 75 mg docosahexaenoic acid. There was a significant fall of triglycerides from an initial 521 mg/dl on average to 334 mg/dl. Total cholesterol was reduced from 266 mg/dl to 233 mg/dl with a continuous fall throughout the study period, ldl cholesterol being the main part, falling from 227 mg/dl to 192 mg/dl. These changes were accompanied by a reduction of apolipoprotein A1 from 118 mg/dl to 109 mg/dl and of B from 212 mg/dl to 204 mg/dl. Parameters of whole blood viscosity decreased significantly (viscous component eta' from 6.81 to 6.44 mPas--elastic component eta" from 1.85 to 1.53 mPas), while the plasma viscosity remained unchanged with 1.44 mPas. The improvement of flow properties results from adherence of omega-3 fatty acids to the phospholipids of the red cell membrane. The conclusion is that supplementation with fish oil in addition to normal food intake of dialysis patients contributes to an improvement of lipoprotein metabolism and flow properties. Thus, two risk factors concerning thrombosis and cardiovascular diseases can be positively influenced.

Does fish oil lower blood pressure? A meta-analysis of controlled trials

BACKGROUND

In a meta-analysis of 31 placebo-controlled trials on 1356 subjects, we examined the effect of omega-3 fatty acids in fish oil on blood pressure by grouping studies that were similar in fish oil dose, length of treatment, health of the subjects, or study design.

METHODS AND RESULTS

The mean reduction in blood pressure caused by fish oil for the 31 studies was -3.0/-1.5 mm Hg (95% confidence intervals: systolic blood pressure: -4.5, -1.5; diastolic blood pressure: -2.2, -0.8). There was a statistically significant dose-response effect when studies were grouped by omega-3 fatty acid dose: -1.3/-0.7 mm Hg at doses < or = 3 g/d, -2.9/-1.6 mm Hg at 3.3 to 7 g/d, and -8.1/-5.8 mm Hg at 15 g/d. Both eicosapentaenoic acid and docosahexaenoic acid were significantly related to blood pressure response. There was no effect on blood pressure in eight studies of "healthy" persons (mean reduction, -0.4/-0.7 mm Hg) at an overall mean dose of 4.2 g omega-3 fatty acids/d. By contrast, there was a significant effect of -3.4/-2.0 mm Hg in the group of hypertensive studies with a mean fish oil dose of 5.6 g/d and on systolic blood pressure only in six studies of hypercholesterolemic patients (-4.4/-1.1 mm Hg) with a mean dose of 4.0 g/d. A nonsignificant decrease in blood pressure was observed in four studies of patients with atherosclerotic cardiovascular disease (-6.3/-2.9 mm Hg). Variations in the length of treatment (from 3 to 24 weeks), type of placebo, and study design (crossover or parallel groups) did not appear to account for inconsistent findings among studies.

CONCLUSIONS

There is a dose-response effect of fish oil on blood pressure of -0.66/-0.35 mm Hg/g omega-3 fatty acids. The hypotensive effect may be strongest in hypertensive subjects and those with clinical atherosclerotic disease or hypercholesterolemia.

Lipoprotein metabolism and renal failure

Lipoprotein metabolism is altered in the majority of patients with renal insufficiency and renal-failure, but may not necessarily lead to hyperlipidemia. The dyslipoproteinemia of renal disease has characteristic abnormalities of the apolipoprotein (apo) profile and lipoprotein composition. It develops during the asymptomatic stages of renal insufficiency and becomes more pronounced as renal failure advances. The qualitative characteristics of renal dyslipoproteinemia are not modified substantially by dialysis treatment. Patients with chronic renal disease may therefore be exposed to dyslipoproteinemia for long periods of time. The characteristic plasma lipid abnormality is a moderate hypertriglyceridemia. The alterations of lipoprotein metabolism affect both the apoB-containing very low-density and intermediate-density, and low-density lipoproteins and the apoA-containing high-density lipoproteins. The main underlying abnormality of lipoprotein transport is a decreased catabolism of the apoB-containing lipoproteins caused by decreased activity of lipolytic enzymes and altered lipoprotein composition. There is an increase of intact or partially metabolized, triglyceride-rich, apoB-containing lipoproteins with a disproportionate elevation of apoC-III and, to a lesser extent, apoE, resulting in a marked increase of the intermediate-density lipoproteins and an enrichment of triglycerides, apoC-III, and apoE in the low-density lipoproteins. In high-density lipoproteins there are decreases in the concentrations of cholesterol, apolipoproteins A-I and A-II, and the high-density lipoprotein-2 to high-density lipoprotein-3 ratio. These abnormalities result in a characteristic decrease of the apoA-I to apoC-III ratio and anti-atherogenic index apoA-I/apoB. The pathophysiologic links between the renal insufficiency and the abnormalities of lipoprotein transport are still poorly defined. Changes in the action of insulin on lipolytic enzymes, possibly mediated via increased levels of parathyroid hormone, have been suggested to play a contributory role. The clinical consequences of a defective lipoprotein transport may be related to the atherogenic character of lipoprotein abnormalities. Renal dyslipoproteinemia may contribute to the development of atherosclerotic vascular disease and progression of glomerular and tubular lesions with subsequent deterioration of renal function. Dietary and/or pharmacologic intervention may ameliorate the uremic dyslipoproteinemia, but the long-term clinical effects of such treatment have yet to be established.

Lipid abnormalities in chronic uremic patients. Response to treatment with gemfibrozil

Seventy-four patients with end stage renal failure were studied. Forty-six of them were on hemodialysis (HD) while 28 were on continuous ambulatory peritoneal dialysis (CAPD). In addition 56 nondialysis chronic renal failure (NDCRF) patients with various degree of renal failure were also studied. In all groups serum triglyceride concentrations were significantly higher and HDL cholesterol concentrations were significantly lower compared to age- and sex-matched controls. Total and LDL cholesterol were significantly higher in the NDCRF and CAPD patients compared to controls. In 55 patients (20 on HD, 13 on CAPD and 22 NDCRF) with severe hypertriglyceridemia or diminished HDL cholesterol gemfibrozil 300 mg b.i.d. per os was given for 6 months. Drug treatment reduced significantly serum triglycerides in all groups of patients and increased the levels of HDL cholesterol in CAPD patients. Moreover, a statistically significant decrease of the levels of total and LDL cholesterol was noticed in HD and NDCRF patients. During treatment no significant side effects were observed and liver and muscle enzymes remained within normal values.

Pharmacokinetics of omega-3-fatty acids during ingestion of fish oil preparations

An in vivo comparison of three dosages (3 g, 6 g, 12 g) of two different fish oil preparations in terms of plasma concentrations of their major active components eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was performed. The plasma accumulation was measured during 28 days of ingestion and an equally long wash out period. Data were scrutinized for bioavailability in order to distinguish between the efficiency of the two preparations. Rapid increases in EPA and DHA plasma concentrations can be demonstrated at all dosages during a 28-day ingestion period. EPA accumulated more during ingestion of high than of low dosages of fish oil. DHA revealed almost identical increases and peak values in plasma concentrations in all subgroups. The present data demonstrate dose dependent increases of EPA concentrations whereas DHA plasma concentrations are comparable in all dosages investigated. Measurable EPA and DHA plasma concentration levels are inappropriate means to explain clinical effectiveness. These results were found in both commercially available fish oil preparations. Direct comparison of both preparations revealed no differences in bioavailability.

Cardiovascular risk factors in chronic renal failure and hemodialysis populations

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease (ESRD). Risk factors for cardiovascular disease, including hypertension, lipid abnormalities, left ventricular hypertrophy (LVH), and glucose intolerance, are present more frequently in patients with chronic renal failure than in the general population, even before the onset of replacement therapy. The prevalence, pathogenesis, and significance of these factors in the uremic population are examined, and the potential roles of intervention are reviewed. Evidence suggests, but is not conclusive, that these factors are of predictive value for cardiovascular complications in patients with chronic renal failure. The effect of modification of these factors on cardiovascular morbidity and mortality in this population, especially in the early stages of renal failure, is an important area for further study.

Effects of HMG-CoA reductase inhibitors in hypercholesterolemic patients on hemodialysis

The efficacy of lovastatin and simvastatin, competitive inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase, was investigated in 40 hemodialysis (HD) patients displaying hypercholesterolemia and moderate hypertriglyceridemia (selection of 40 patients required screening of 700 hemodialysis patients). After a four-week placebo period, lovastatin or simvastatin was administered to two groups of 20 patients in increasing doses over a period of three months. Thirty-six patients completed the study. Lovastatin (1st month 20 mg; 2nd and 3rd months 40 mg day-1) and simvastatin (1st month 10 mg, 2nd month 20 mg and 3rd month 40 mg day-1) reduced total serum cholesterol from 280.3 +/- 9.4 to 213.0 +/- 6.7 (-24%) and 295.0 +/- 12.2 to 202.3 +/- 8.9 mg/dl (-31.4%), LDL cholesterol from 161.9 +/- 10.7 to 112.1 +/- 7.9 (-30.8%) and 181.8 +/- 14.7 to 107.4 +/- 8.1 mg/dl (-40.9%), as well as apolipoprotein B (apo B) from 116.0 +/- 6.6 to 83.3 +/- 3.7 (-28.2%) and 134.4 +/- 8.2 to 84.1 +/- 5.3 mg/dl (-37.4%), respectively. Furthermore, the ratio of LDL apo B/LDL cholesterol increased significantly (0.63 +/- 0.02 vs. 0.71 +/- 0.05 and 0.63 +/- 0.02 vs. 0.66 +/- 0.02, respectively). Another remarkable effect was the reduction of cholesterol concentration in VLDL (72.4 +/- 8.9 vs. 47.3 +/- 6.8 [lovastatin] and 78.3 +/- 11.1 vs. 50.7 +/- 8.8 mg/dl [simvastatin], respectively). Therefore, the ratio of triglycerides/cholesterol in VLDL increased (3.2 +/- 0.2 vs. 3.8 +/- 0.3 and 3.2 +/- 0.2 vs. 4.0 +/- 0.2, respectively), indicating VLDL formation poor in cholesterol and rich in triglycerides.(ABSTRACT TRUNCATED AT 250 WORDS)

Fish oil amplifies the effect of propranolol in mild essential hypertension

Forty-seven male patients with mild essential hypertension were randomly allocated to three subgroups. After a run-in period of 4 weeks, the first subgroup (n = 16) received propranolol (80 mg/day) for 36 weeks followed by a placebo period of 4 weeks. The second subgroup (n = 15), after a run-in period of 4 weeks, was given a supplement of encapsulated fish oil (9 g/day) for 36 weeks with a subsequent period of 4 weeks in which fish oil placebo was given. The third subgroup (n = 16), after a run-in period of 4 weeks, was given propranolol (80 mg/day) for 12 weeks, propranolol (80 mg/day) plus fish oil capsules (9 g/day equivalent to 1.8 g/day of eicosapentaenoic acid and 1.1 g/day of docosahexaenoic acid) for 12 weeks, propranolol plus fish oil placebo (same doses for 12 weeks) with a subsequent period of 4 weeks when propranolol placebo was administered. The results indicate a blood pressure-lowering effect of fish oil, which was comparable with that of propranolol. The simultaneous intake of fish oil plus propranolol was more effective than propranolol or fish oil alone. Propranolol treatment resulted in a decrease of plasma norepinephrine, plasma renin activity, and thromboxane B2 formation. After fish oil supplementation, plasma norepinephrine and thromboxane B2 formation were likewise reduced, whereas plasma renin activity appeared increased. The decrease of serum triglycerides, total and low density lipoprotein cholesterol as well as the rise of high density lipoprotein cholesterol are concomitant beneficial effects, which justify the consideration of fish oil alone or in combination with antihypertensive drugs for the treatment of mild hypertension.

Reduction in microalbuminuria in diabetics by eicosapentaenoic acid ethyl ester

Eicosapentaenoic acid (EPA) ethyl ester (1.8 g/d) was administered to 16 diabetic patients (5 insulin-dependent and 11 noninsulin-dependent diabetics) for 6 mon. EPA in total plasma fatty acids increased from 4.0 +/- 2.4 mol% (mean +/- SD) to 7.5 +/- 3.1 mol% (p less than 0.001). Albumin excretion, measured with spot urine, was significantly reduced from 65 to 36 mg/g creatinine (geometric means, p less than 0.001). Fasting blood sugar levels, glycohemogloblin, body weight and blood pressure did not change significantly during the study. There were also no significant changes in serum levels of creatinine, urea nitrogen, total cholesterol and triglycerides. Although no overt hemorrhage was observed in the patients, hematocrit was reduced from 42.6 +/- 2.8% to 41.0 +/- 3.9% (p less than 0.02). Ten other similar diabetic patients (4 insulin-dependent and 6 noninsulin-dependent diabetics) were followed as a reference group, not concomitantly, for 6 mon with neither EPA ethyl ester nor placebo. The parameters mentioned above were not changed significantly in this group during 6 mon. EPA administration might retard the appearance of overt diabetic nephropathy.

Effect of fish oil on atherogenesis in Watanabe heritable hyperlipidemic rabbit

The effect of dietary supplementation with fish oil was investigated in the Watanabe heritable hyperlipidemic (WHHL) rabbit. Rabbits were fed Maxepa (1 g/kg body weight) from weaning for a 6-month period and were compared to controls. Fish oil supplements resulted in significant decreases in plasma triglyceride and cholesterol at 4 weeks after the start of the study, and these differences persisted over the 6-month period. No differences in the distribution of cholesterol or triglyceride among lipoprotein particles were found, nor were there differences in low density lipoprotein particle size. The decreases in plasma cholesterol and triglyceride were accompanied by significant increases in the percent of eicosapentaenoic and docosahexaenoic acids in both plasma and platelets. Fish oil supplementation resulted in a decrease in platelet count and response to the aggregating agents adenosine diphosphate, arachidonic acid, and collagen. Systolic blood pressure was significantly lower in the rabbits fed fish oil. At the end of the study period, aortic free and esterified cholesterol and intimal surface area covered with plaque were determined in the arch and in the descending and abdominal aorta. Significantly less cholesterol was found in the descending and abdominal aorta. These differences were mirrored by decreased activities of acid lipase and N-acetyl-beta-glucosaminidase. In contrast, no differences in the intimal surface area covered with plaque were found. In conclusion, dietary fish oil resulted in a decrease in aortic lipid deposition in the WHHL rabbit, which may have been due to decreases in plasma triglyceride and cholesterol, platelet count and aggregability, and systolic blood pressure.

Short- and long-term outcome of percutaneous transluminal coronary angioplasty in chronic dialysis patients

Accelerated atherosclerosis occurs in chronic renal failure. The role of percutaneous transluminal coronary angioplasty (PTCA) in chronic renal failure patients requiring dialysis has not been characterized. We studied 17 chronic dialysis patients requiring PTCA over a 6-year period. Their mean age was 60 years, four were diabetic, eight had severe hypertension, and seven had unstable angina. Angiographic success was achieved in 47 of 49 (96%) stenoses attempted, including multivessel PTCA in 12 patients. There was one procedural death, two non-Q wave myocardial infarctions following PTCA, and one additional in-hospital noncardiac death. The 15 survivors were asymptomatic on discharge (mean stay 11 days), but recurrent angina developed within 6 months in 12 patients. Angiography in 11 of these 12 patients demonstrated restenosis of 26 of 32 (81%) dilated sites. Repeat PTCA in six patients was followed by return of angina in four patients with restenosis in 11 of 12 sites. Bypass surgery was ultimately performed in four patients with long-term angina relief. During follow-up (mean 20 months), seven patients died (five from chronic renal failure, two cardiac deaths). Thus although PTCA in chronic dialysis patients is technically feasible and provides relief of angina, aggressive restenosis limits the long-term benefit. Coronary bypass surgery may be the preferred therapy for this unique patient group.

Omega-3 fatty acid dietary supplementation in systemic lupus erythematosus

The effect of dietary fish oil (Omega-3 fatty acids--eicosapentenoic acid [EPA] and docosahexaenoic acid [DHA] on several mechanisms involved in immune, inflammatory and atherosclerotic vascular disease was determined in 12 subjects with systemic lupus erythematosus (SLE) and nephritis. These out-patients supplemented their usual diet for five weeks with daily doses of 6 g of fish oil, followed by a five-week washout period, then five weeks of 18 g of fish oil daily. The platelet EPA content rose six-fold with the lower and 15-fold with the higher dose of fish oil, and similar changes occurred to the platelet DHA content. The platelet arachidonic acid incorporation was reduced by 16 and 20%, respectively. These changes were associated with a reduction in collagen-induced platelet aggregation and an increase in red cell flexibility and a decrease in whole blood viscosity. Prostacyclin (PGI2) production was unaffected by the fish oil, but PGI3 formation correlated with its administration and dosage. Neutrophil leukotriene B4 release was reduced 78 and 42%, respectively, by the low and higher doses of fish oil. The higher fish oil dose induced a 38% decrease in triglyceride and a 39% reduction in VLDL cholesterol associated with a 28% rise in HDL, cholesterol. The fish oil had no effect on immune complex or anti-DNA antibody titer, albuminuria, intraplatelet serotonin or [14C]-serotonin release from platelets. We conclude that in patients with lupus nephritis, dietary supplementation with fish oil affects the mechanisms involved in inflammatory and atherosclerotic vascular disease.

The effects of omega-3 polyunsaturated fatty acids on blood pressure: a methodologic analysis of the evidence

The potentially beneficial blood pressure (BP)-lowering effects of marine omega-3 polyunsaturated fatty acids (omega-3-PUFAs) remain controversial. The objective of this qualitative and quantitative (meta-analysis) analysis was to evaluate the results of all available randomized controlled trials that studied the effect of omega-3-PUFAs on BP response. A comprehensive search of the English literature from 1970 to 1988 disclosed only six randomized controlled investigations out of 22 published reports. Four of these were evaluable and therefore eligible for this analysis. Of these, only one evaluated hypertensive subjects. In two trials, there were statistically significant reductions in BP; the one reporting an investigation of hypertensive subjects showed the greatest reduction. Using established methodologic criteria, the quality of each report was evaluated by independent observers. Following this appraisal, the outcomes of each investigation were reanalyzed and pooled using a meta-analysis. There was no statistically significant difference between the omega-3-PUFA groups and the control groups, possibly because of failure to include hypertensive subjects in all but one trial. Despite the positive effects in two studies, little scientifically valid evidence is available to demonstrate a significant BP-lowering effect of omega-3-PUFAs. Areas needing more attention in future research are identified and methods to improve study designs are suggested.

Effect of eicosapentaenoic acid ethyl ester on proteinuria of streptozotocin-induced diabetes mellitus in rats

Streptozotocin (45 mg/kg) was intravenously administered to 7-week-old Wistar rats through their tail veins. After 11 days, the rats were divided into two groups. One group was fed a lipid-free diet (90%, w/w) plus lard (8%) and safflower oil (2%) for four weeks (Diet 1 group, n = 12). The other group was fed in the same way, except that safflower oil was replaced by 90% pure eicosapentaenoic acid (EPA) ethyl ester (Diet 2 group, n = 13). Twenty-four-hour urine was collected just before the diets started and during the experiment at 7-day intervals. In the second and third week, the levels of proteinuria were significantly lower in the Diet 2 group than they were in the Diet 1 group. There was no significant difference in the levels of creatinine, urea nitrogen, or lipids in plasma or in body weights between the two groups after four weeks on the diets. Because Diet 2 reduced proteinuria of diabetic rats compared to Diet 1, an EPA-rich diet may retard the development of diabetic nephropathy.

Effect of dietary omega-3 fatty acid on serum lipids, platelet function, and atherosclerosis in Watanabe heritable hyperlipidemic rabbits

Omega-3 fatty acids have been shown to lower plasma cholesterol and triglyceride concentrations in humans. However, the effects of these fatty acids on the interactions among lipid concentrations, platelet activity, and atherogenesis have not been characterized in humans or in animals with low density lipoprotein (LDL) receptor deficiencies. To test the hypothesis that omega-3 fatty acids exert a protective effect in LDL receptor-deficient animals by lowering hyperlipidemia, reducing platelet aggregation, and reducing the severity of atherosclerosis, we evaluated young homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits that were fed omega-3 fatty acids. One-month-old male and female WHHL rabbits were placed on either a control diet (standard laboratory rabbit chow) or a diet supplemented with Menhaden fish oil (MFO), which contained eicosapentaenoic acid (EPA). Consumption measurements during the 5 months of the study indicated that the MFO-fed group received 150 to 200 mg/kg/day of EPA. Six-month-old, MFO-fed, female WHHL rabbits had significantly lower plasma concentrations of total cholesterol (582 +/- 20 mg/dl vs. 856 +/- 44 mg/dl, control, p less than 0.05) and triglycerides (266 +/- 21 mg/dl vs. 459 +/- 15 mg/dl, control, p less than 0.05), with lower serum/plasma lipoprotein concentrations [very low density lipoprotein (VLDL), LDL, high density lipoprotein (HDL)] compared to control female WHHL rabbits. Male MFO-fed rabbits had only significantly lower VLDLs (46 +/- 9 mg/dl) compared to control male WHHL rabbits (156 +/- 9 mg/dl, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of diets containing fish and fish oils on disease risk factors in humans

Fish and fish oils are rich in omega 3 polyunsaturated fatty acids which are capable of acting as both a source of active eicosanoids and as inhibitors of synthesis of eicosanoids from arachidonic acid by a variety of human cells. There is an extensive literature on the role of omega 3 polyunsaturates in ameliorating the risk factors associated with coronary heart disease, including both atherosclerotic and thrombotic factors. In addition, there is a limited number of studies which report the results of trials testing the effects of fish oils on other clinical conditions including diabetes, arthritis, migraine and psoriasis. There appears to be sufficient evidence to suggest that patients at risk from heart disease could benefit from low dose (1-6 g/day) of fish oil in conjunction with a prudent diet.

Fish oil has beneficial effects on lipids and renal disease of nephrotic rats

The effects of fish oil on serum lipids, eicosanoid production, fibrinolysis, and renal disease of nephrotic rats were studied. Three groups of rats were given adriamycin to induce nephrotic syndrome. They were pair-fed diets containing 14% beef fat, 3%, and 14% fish oil, and killed at 4 weeks. Marked beneficial effects of the fish oil on plasma triglycerides, total cholesterol, and LDL cholesterol were observed. Fish oil suppressed dienoic eicosanoid production. Protection of renal function and morphology was achieved in the fish oil fed groups, as evidenced by lower serum creatinine levels and lesser degrees of tubular dilatation and intraluminal protein in the kidney tubules. We conclude that fish oil, rich in n-3 fatty acids, is beneficial to the plasma lipids and may prevent progression of renal disease in this model of nephrotic syndrome. These two events may be interrelated.

Effects of dietary fish oil on serum lipids and blood coagulation in peritoneal dialysis patients

The effects of a daily fish oil supplement rich in eicosapentaenoic acid were studied in 11 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Serum lipids, platelet aggregation studies, and template bleeding times were determined before and after 4 weeks of fish oil treatment. The lipid studies were repeated approximately 20 weeks after stopping fish oil supplement. At the end of the treatment period, serum triglycerides (mean +/- SEM) decreased from 297 +/- 42 to 211 +/- 29 mg/dL (P less than .01), high density lipoprotein (HDL) cholesterol fell from 45 +/- 3 to 41 +/- 3 mg/dL (P less than .05), and low density lipoprotein (LDL) cholesterol increased from 172 +/- 16 to 208 +/- 19 mg/dL (P less than .05). After discontinuing the fish oil supplement, the triglycerides increased to 278 +/- 39 mg/dL, which was no different than the value before fish oil treatment. No significant changes occurred in template bleeding time (TBT), platelet count, hematocrit, or platelet aggregation response. Clinically important uremic bleeding was not apparent. We conclude that in CAPD patients a fish oil supplement favorably effects hypertriglyceridemia and can be ingested without promoting uremic bleeding. The likely beneficial impact on atherogenesis resulting from the lowering of the triglycerides may, however, be counteracted by concomitant changes in HDL- and LDL-cholesterol.

Intake of different eicosapentaenoic acid-containing lipids and fatty acid pattern of plasma lipids in the rats

The ethyl ester of eicosapentaenoic acid (EPA) is the only pure EPA-containing lipid available in bulk for oral administration. However, there is doubt as to whether EPA ethyl ester can efficiently increase the plasma levels of EPA in comparison with the ability of other kinds of EPA-containing lipids to do so. Therefore, two other kinds of EPA-containing lipids were prepared to study the efficiency of oral administration of those lipids for increasing the EPA content in plasma phospholipids and cholesteryl esters. EPA-containing lipids which were investigated were [A] 1,2,3-trieicosapentaenoyl-glycerol, [B] 2-eicosapentaenoyl-phosphatidylcholine and [C] ethyl ester of EPA. An adjusted amount of lipids [A], [B] and [C] was administered to rats through a gastric tube for 4 days (the first experiment) or for 10 days (the second experiment), and the fatty acid composition of plasma phospholipids and cholesteryl esters was determined. In the first experiment, there were no significant differences in the efficiency for increasing EPA levels in either phospholipids or cholesteryl esters among the lipids. In the second experiment, the EPA levels of both plasma phospholipids and cholesteryl esters of rats administered ethyl ester of EPA were significantly higher than those of rats administered 2-eicosapentaenoyl-phosphatidylcholine. The EPA levels of the rats administered 1,2,3-trieicosapentaenoyl-glycerol were between the levels of the two groups mentioned above, but the differences in the EPA levels were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of fish oil concentrates on hemorheological and hemostatic aspects of diabetes mellitus: a preliminary study

Fish oil concentrates (Max EPA) were given without other diet modification for eight weeks to five insulin-dependent diabetics and five healthy volunteers, in order to determine their effect on possible in vitro indices of thrombosis. Cholesterol, HDL, LDL, fasting blood sugar, hemoglobin A1c, platelet count, and the osmotic fragility of red blood cells were not significantly changed from baseline values after eight weeks of fish oil consumption. Serum triglyceride levels were lowered by the fish oil (diabetics 130 +/- 23 to 89 +/- 26 mg/dl: normals 107 +/- 16 to 57 +/- 5 mg/dl). Nine out of ten subjects required more arachidonic acid to aggregate their platelets, and six out of ten required more collagen. Whole blood viscosity at low shear rates was increased in diabetics before the fish oil ingestion, and was reduced both in normals and in diabetics after eight weeks of treatment. Before fish oil administration, the diabetics had higher levels of von Willebrand Factor (vWF) (208 +/- 31%) than did controls (117 +/- 26%). There was a statistically significant decrease of serum von Willebrand Factor both in diabetics (p less than 0.01) and in normals (p less than 0.05) after six weeks of treatment. Analysis of the multimeric composition of the vWF indicated that the vWF molecule was not altered. Addition of eicosapentaenoic acid (EPA) or crude fish oil to human umbilical cord endothelial cell cultures did not change vWF levels in the supernatant. Whether these changes in platelet aggregation, whole blood viscosity and vWF can actually be translated into an in vivo amelioration of the vascular complications in diabetes remains to be determined in a carefully controlled clinical trial.

Dietary fat in experimental nephrotic syndrome: beneficial effects of fish oil on serum lipids and, indirectly, on the kidney

Three isocaloric diets with different fat composition were fed to rats for seven weeks after the production of nephrotic syndrome by adriamycin. The effects of feeding 3% and 14% fish oil were compared with those of feeding beef fat. At the fourth week of feeding the levels of triglycerides and cholesterol were lower in both fish oil fed groups. At the seventh week these levels, and the LDL cholesterol, were lower only in the 14% fish oil group. In rats fed beef fat, but not in those fed fish oil, there was a striking positive correlation of the four-week serum triglycerides and cholesterol with the seven-week serum creatinine level and with the degree of glomerular hyalinosis and endothelial swelling. The favorable effects of fish oil feeding on serum lipids may have a protective effect on the development of glomerular damage.