Role of arachidonic acid in the regulation of the inflammatory response in TNF-alpha-treated rats

Omega-3 fatty acids enhance the beneficial effect of BCAA supplementation on muscle function following eccentric contractions

Background

Methods

Results

Conclusions

4-week eicosapentaenoic acid-rich fish oil supplementation partially protects muscular damage following eccentric contractions

BACKGROUND

We previously showed 8-week of fish oil supplementation attenuated muscle damage. However, the effect of a shorter period of fish oil supplementation is unclear. The present study investigated the effect of fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for 4 weeks on muscular damage caused by eccentric contractions (ECCs) of the elbow flexors.

METHODS

Twenty-two untrained men were recruited in this double-blind, placebo-controlled, parallel design study and the subjects were randomly assigned to the EPA and DHA group (EPA and DHA, n = 11) and placebo group (PL, n = 11). They consumed either EPA 600 mg and DHA 260 mg per day or placebo supplement for 4 weeks prior to exercise. Subjects performed 60 ECCs at 100 % maximal voluntary contraction (MVC) using a dumbbell. Changes in MVC torque, range of motion (ROM), upper arm circumference, muscle soreness, echo intensity, muscle thickness, serum creatine kinase (CK), and interleukin-6 (IL-6) were assessed before exercise; immediately after exercise; and 1, 2, 3, and 5 days after exercise.

RESULTS

ROM was significantly higher in the EPA and DHA group than in the PL group immediately after performing ECCs (p < 0.05). No differences between groups were observed in terms of MVC torque, upper arm circumference, muscle soreness, echo intensity, and thickness. A significant difference was observed in serum CK 3 days after ECCs (p < 0.05).

CONCLUSIONS

We concluded that shorter period EPA and DHA supplementation benefits joint flexibility and protection of muscle fiber following ECCs.

Supplementation of Ω-3 Fatty Acids in Parenteral Nutrition Beneficially Alters Phospholipid Fatty Acid Pattern

BACKGROUND

The clinical safety and the uptake of omega-3 polyunsaturated fatty acids (PUFA) into the serum phospholipids and erythrocyte membranes after administration of fish-oil-supplemented parenteral nutrition (PN) was investigated in colorectal surgical patients.

METHODS

Forty patients undergoing colorectal surgery (n = 40) and with an indication for PN were enrolled in a prospective, double-blind, randomized study to receive an omega-3 PUFA-supplemented 20% lipid emulsion (Lipoplus; B. Braun Melsungen, Melsungen, Germany; test group, n = 19) for 5 days postoperatively. The control group received a standard 20% fat emulsion (Lipofundin MCT/LCT, B. Braun Melsungen, Melsungen, Germany, control group, n = 21). Clinical outcome parameters and safety were assessed by means of adverse events recording clinical parameters and hematologic analyses. The contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as arachidonic acid (AA), in phospholipid fractions in plasma and in erythrocytes were analyzed preoperatively, on postoperative days 1, 6, and 10 using liquid gas chromatography.

RESULTS

Both fat emulsions were well tolerated, and none of the adverse events was considered to be related to treatment. Postoperative infectious complications occurred in 4 patients of the omega-3 PUFA group vs 7 patients in the control group. As compared with the control group, the omega-3 PUFA group had significantly increased levels of EPA in the membranes of the erythrocytes in postoperative day 6 (2.0% +/- 0.9% vs 0.8% +/- 0.5% fatty acid methyl esters, [FAME]) and postoperative day 10 (2.1% +/- 0.8% vs 0.9% +/- 0.7% FAME, p < .05). Also, the EPA levels in the serum phospholipids were significantly higher than in the control group on the same postoperative days (7.0% +/- 2.6% vs 1.3% +/- 0.8% and 3.6% +/- 1.0% vs 1.0% +/- 0.4% FAME, p < .05). The DHA levels in the serum phospholipids were significantly higher in the omega-3 PUFA group compared with the control on postoperative days 6 and 10 (11.8% +/- 1.9% vs 8.4% +/- 1.5% and 11.2% +/- 1.6% vs 8.5% +/- 1.4% FAME, p < .05). AA levels were not significantly different in the both groups.

CONCLUSIONS

Omega-3-fatty-acids-supplemented fat emulsions for parenteral administration are safe and very well tolerated. This study demonstrates that parenteral administration of omega-3-PUFA-enriched fat emulsions leads to increased incorporation of EPA and DHA into phospholipids in serum and erythrocytes, whereas AA levels remain unchanged. Thus, postoperative parenteral administration of omega-3-PUFA-enriched lipid emulsions could have an impact on the postoperative inflammatory response after abdominal surgery and could be used in standard postoperative care when PN is indicated.

Metabolomic Response of Skeletal Muscle to Aerobic Exercise Training in Insulin Resistant Type 1 Diabetic Rats

The etiology of insulin resistance in Type 1 Diabetes (T1D) is unknown, however it affects approximately 20% of T1D patients. Intramyocellular lipids (IMCL) have been identified as a mechanism of insulin resistance. We examined skeletal muscle of T1D rats to determine if alterations in lipid metabolism were evident and whether aerobic exercise training improves IMCL and insulin resistance. To do so, 48 male Sprague-Dawley rats were divided into control (C), sedentary diabetes (D) and diabetes exercise (DX) groups. Following multiple low-dose Streptozotocin (STZ) injections (20 mg/kg), glycemia (9-15 mM) was maintained using insulin treatment. DX were treadmill trained at high intensity (~75% V02max; 5days/week) for 10 weeks. The results demonstrate that D exhibited insulin resistance compared with C and DX, indicated by decreased glucose infusion rate during a hyperinsulinemic-euglycemic clamp (p < 0.05). There were no differences between C and DX, suggesting that exercise improved insulin resistance (p < 0.05). Metabolomics analysis revealed a significant shift in lipid metabolism whereby notable fatty acid metabolites (arachidonic acid, palmitic acid and several polyunsaturated fatty acids) were significantly elevated in D compared to C and DX. Based on the intermediates observed, insulin resistance in T1D is characterized by an insulin-desensitizing intramyocellular fatty acid metabolite profile that is ameliorated with exercise training.

Eicosapentaenoic and docosahexaenoic acids-rich fish oil supplementation attenuates strength loss and limited joint range of motion after eccentric contractions: a randomized, double-blind, placebo-controlled, parallel-group trial

Purpose

This study investigated the effect of eicosapentaenoic and docosahexaenoic acids-rich fish oil (EPA + DHA) supplementation on eccentric contraction-induced muscle damage.

Methods

Twenty-four healthy men were randomly assigned to consume the EPA + DHA supplement (EPA, n = 12) or placebo (PL, n = 12) by the double-blind method. Participants consumed EPA + DHA or placebo supplement for 8 weeks prior to exercise and continued it until 5 days after exercise. The EPA group consumed EPA + DHA-rich fish oil containing 600 mg EPA and 260 mg DHA per day. Subjects performed five sets of six maximal eccentric elbow flexion exercises. Changes in the maximal voluntary contraction (MVC) torque, range of motion (ROM), upper arm circumference, muscle soreness as well as serum creatine kinase, myoglobin, IL-6, and TNF-α levels in blood were assessed before, immediately after, and 1, 2, 3, and 5 days after exercise.

Results

MVC was significantly higher in the EPA group than in the PL group at 2–5 days after exercise (p < 0.05). ROM was also significantly greater in the EPA group than in the PL group at 1–5 days after exercise (p < 0.05). At only 3 days after exercise, muscle soreness of the brachialis was significantly greater in the PL group than in the EPA group (p < 0.05), with a concomitant increase in serum IL-6 levels in the PL group.

Conclusion

Eight-week EPA + DHA supplementation attenuates strength loss and limited ROM after exercise. The supplementation also attenuates muscle soreness and elevates cytokine level, but the effect is limited.

The addition of medium-chain triglycerides to a purified fish oil-based diet alters inflammatory profiles in mice

OBJECTIVE

Parenteral nutrition associated liver disease (PNALD) is a deadly complication of long term parenteral nutrition (PN) use in infants. Fish oil-based lipid emulsion has been shown in recent years to effectively treat PNALD. Alternative fat sources free of essential fatty acids have recently been investigated for health benefits related to decreased inflammatory response. We hypothesized that the addition of medium-chain triglycerides (MCT) to a purified fish oil-based diet would decrease the response to inflammatory challenge in mice, while allowing for sufficient growth and development.

MATERIALS/METHODS

Six groups of ten adult male C57/Bl6 mice were pair-fed different dietary treatments for a period of twelve weeks, varying only in fat source (percent calories by weight): 10.84% soybean oil (SOY), 10% coconut oil (HCO), 10% medium-chain triglycerides (MCT), 3% purified fish oil (PFO), 3% purified fish oil with 3% medium-chain triglycerides (50:50 MCT:PFO) and 3% purified fish oil with 7.59% medium-chain triglycerides (70:30 MCT:PFO). An endotoxin challenge was administered to half of the animals in each group at the completion of dietary treatment.

RESULTS

All groups demonstrated normal growth throughout the study period. Groups fed MCT and HCO diets demonstrated biochemical essential fatty acid deficiency and decreased IL-6 and TNF-α response to endotoxin challenge. Groups containing PFO had increased inflammatory response to endotoxin challenge, and the addition of MCT to PFO mitigated this inflammatory response.

CONCLUSION

These results suggest that the addition of MCT to PFO formulations may decrease the host response to inflammatory challenge, which may pose potential for optimized PN formulations. Inclusion of MCT in lipid emulsions given with PN formulations may be of use in therapeutic interventions for disease states resulting from chronic inflammation.

The effect of varying ratios of docosahexaenoic acid and arachidonic acid in the prevention and reversal of biochemical essential fatty acid deficiency in a murine model

OBJECTIVE

Essential fatty acids (EFA) are necessary for growth, development, and biological function, and must be acquired through the diet. While linoleic acid (LA) and alpha-linolenic acid (ALA) have been considered the true EFAs, we previously demonstrated that docosahexaenoic acid (DHA) and arachidonic acid (AA) taken together as the sole source of dietary fatty acids can prevent biochemical essential fatty acid deficiency (EFAD). This study evaluates the effect of varying dietary ratios of DHA:AA in the prevention and reversal of biochemical EFAD in a murine model.

METHODS

Using a murine model of EFAD, we provided mice with 2.1% of daily caloric intake in varying DHA:AA ratios (1:1, 5:1, 10:1, 20:1, 200:1, 100:0) for 19 days in association with a liquid high-carbohydrate fat-free diet to evaluate the effect on fatty acid profiles. In a second experiment, we evaluated the provision of varying DHA:AA ratios (20:1, 200:1, 100:0) on the reversal of biochemical EFAD.

RESULTS

Mice provided with DHA and AA had no evidence of biochemical EFAD, regardless of the ratio (1:1, 5:1, 10:1, 20:1, 200:1, 100:0) administered. Biochemical EFAD was reversed with DHA:AA ratios of 20:1, 200:1, and 100:0 following 3 and 5 weeks of dietary provision, although the 20:1 ratio was most effective in the reversal and stabilization of the triene:tetraene ratio.

CONCLUSION

Provision of DHA and AA, at 2.1% of daily caloric intake in varying ratios can prevent biochemical evidence of EFAD and hepatic steatosis over the short-term, with a ratio of 20:1 DHA:AA most effectively reversing EFAD.

Purified fish oil eliminating linoleic and alpha linolenic acid meets essential fatty acid requirements in rats

This study examined whether purified fish oil (PFO) supplemented to an essential fatty acid deficient (EFAD) diet meets EFA needs in rats. The EFAD diet contained 10% hydrogenated coconut oil (HCO). A similar diet contained 7% HCO and 3% PFO which also provided 2.84% arachidonic acid (AA), 52.50% eicosapentaenoic acid (EPA) and 35.73% docosahexaenoic acid (DHA) but no linoleic acid (LA) or alpha linolenic acid (ALA). A 10% soybean oil control diet provided ample LA and ALA. After 4 weeks of feeding, blood glucose, plasma triglyceride and phospholipid fatty acid profiles, C-reactive protein (CRP), TNF and IL-6 were determined after saline or LPS injection. EFAD developed with the HCO diet with triene:tetraene ratios in plasma phospholipids >.20, which remained <.02 with the control and HCO+PFO diets. Mead acid levels significantly increased by a factor of 10 with the HCO diet compared to the AIN and HCO+PFO diets and were significantly lowest with the HCO+PFO diet. 18:1 n9 levels were significantly higher in plasma phospholipids and triglycerides with the HCO diet. CRP levels were significantly highest with the control diet and significantly lowest with the HCO diet. LPS significantly increased 18:1 n9 and cytokines, and decreased AA and plasma glucose in all diets and significantly increased plasma triglycerides and decreased plasma glucose in controls. Providing AA, EPA and DHA in EFAD prevents EFAD over the short-term as reflected in Mead acid production, triene:tetraene ratio, and de novo lipogenesis and may reduce the inflammatory response to LPS.

Docosahexaenoic acid and arachidonic acid prevent essential fatty acid deficiency and hepatic steatosis

OBJECTIVES

Essential fatty acids are important for growth, development, and physiologic function. α-Linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, the authors hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids.

METHODS

Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, the authors provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis.

RESULTS

Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks.

CONCLUSION

Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without α-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model.

Human monocyte differentiation stage affects response to arachidonic acid

AA-induced cell death mechanisms acting on human monocytes and monocyte-derived macrophages (MDM), U937 promonocytes and PMA-differentiated U937 cells were studied. Arachidonic acid induced apoptosis and necrosis in monocytes and U937 cells but only apoptosis in MDM and U937D cells. AA increased both types of death in Mycobacterium tuberculosis-infected cells and increased the percentage of TNFalpha+ cells and reduced IL-10+ cells. Experiments blocking these cytokines indicated that AA-mediated death was TNFalpha- and IL-10-independent. The differences in AA-mediated cell death could be explained by high ROS, calpain and sPLA-2 production and activity in monocytes. Blocking sPLA-2 in monocytes and treatment with antioxidants favored M. tuberculosis control whereas AA enhanced M. tuberculosis growth in MDM. Such evidence suggested that AA-modulated effector mechanisms depend on mononuclear phagocytes' differentiation stage.

Effect of a dietary intervention and n-3 fatty acid supplementation on measures of serum lipid and insulin sensitivity in persons with HIV

BACKGROUND

Elevated serum triglyceride and low HDL-cholesterol concentrations have been reported in persons with HIV.

OBJECTIVE

The effect of a dietary intervention plus n-3 (omega-3) fatty acid supplementation on serum triglycerides and markers of insulin sensitivity was investigated.

DESIGN

Fifty-four persons with HIV and elevated serum triglycerides (>150 mg/dL) and/or abnormal Quantitative Insulin Sensitivity Check Index values (<0.35 but >0.30) were recruited for a dietary intervention in which total fat, type of fat, fiber, and glycemic load were controlled along with supplementation with n-3 fatty acids to achieve an intake of 6 g/d. The subjects were randomly assigned to an intervention or control group, and serum lipids, markers of insulin sensitivity, and serum phospholipid fatty acids were measured in both groups at baseline, 3 wk, and 13 wk.

RESULTS

Triglycerides in the intervention group decreased from a median of 180 mg/dL (interquartile range: 141, 396) to 114 mg/dL (interquartile range: 84, 169) from baseline to 3 wk, whereas they remained stable in the control group (P = 0.003). Serum phospholipid fatty acids indicated a decrease in de novo lipogenesis and a decrease in arachidonic acid (% nmol; P <or= 0.001) in the intervention group. At 3 wk, the insulin area under the curve decreased but not significantly.

CONCLUSIONS

Diet and n-3 fatty acid supplementation dramatically reduced serum triglycerides, decreased arachidonic acid in the phospholipids fraction, and appeared to decrease the de novo lipogenesis associated with the metabolic syndrome in the intervention group.

Long-chain polyunsaturated fatty acids modulate interleukin-1beta-induced changes in behavior, monoaminergic neurotransmitters, and brain inflammation in rats

Recent evidence has suggested that an imbalance between membrane (n-3) and (n-6) fatty acids may contribute to the etiology of autoimmune and neurodegenerative diseases. In this study, the mechanisms by which eicosapentaenoic acid (EPA), gamma-linolenic acid (GLA), and arachidonic acid (AA) modulate neurotransmitters, behavior, and brain inflammation were evaluated in rats that received central saline or interleukin-1beta (IL-1) administrations. In rats treated with saline, only the AA-enriched diet significantly increased anxiety-like behavior in the elevated plus maze, which was associated with increased corticosterone secretion. AA also increased the turnover of dopamine (DA), noradrenaline (NA), and serotonin (5-HT) in the amygdala and increased the prostaglandin (PG)E(2) level in the hippocampus. IL-1 administration slowed rat learning in the water maze and increased anxiety-like behavior, changes which were associated with increased homovanillic acid and 5-HT turnover, decreased NA in the hippocampus and amygdala, decreased DA in the frontal cortex, and decreased IL-10 in limbic brain regions. Increased corticosterone secretion following IL-1 administration was accompanied by increased NA turnover in the hippocampus (P < 0.05) and increased PGE(2) concentration (P < 0.01) in the limbic brain regions. Of the 3 diets tested, only EPA attenuated IL-1-induced behavioral changes (P < 0.05 or 0.01), which was associated with the modulation of EPA on the neuroendocrine and immune changes induced by IL-1. GLA reduced hippocampal PGE(2) concentration in rats given IL-1 (P < 0.01). AA did not counteract any of the changes induced by IL-1. These results suggest that EPA, GLA, and AA play different roles in the neuroendocrine-immune network.

Preoperative oral supplementation with long-chain Omega-3 fatty acids beneficially alters phospholipid fatty acid patterns in liver, gut mucosa, and tumor tissue

BACKGROUND

The uptake of omega-3 polyunsaturated fatty acids (PUFAs) into the liver, gut mucosa, and tumor tissue and plasma levels after preoperative administration of supplemented enteral nutrition was investigated in patients with malignancies of the upper gastrointestinal tract. The objective of the study was to evaluate the incorporation of preoperatively administrated PUFAs, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) into cell phospholipids.

METHODS

Patients undergoing major gastrointestinal surgery (n = 40) were prospectively randomized to receive a PUFA-supplemented liquid oral diet 5 days preoperatively or an isocaloric control diet. The planned diet intake was 1000 mL/d providing 3.7 g of PUFA. The diet was given in addition to the usual hospital diet. The phospholipid fractions in plasma were analyzed on the day of surgery. Tissue samples of liver, gut mucosa (small intestine), and tumor were taken during surgery and homogenized. EPA and DHA content was analyzed using liquid gas chromatography.

RESULTS

Both patient groups (PUFA group: n = 20; control group: n = 20) were similar in age, weight, and surgical procedures. As compared with the control group, the PUFA group had significantly increased levels of EPA in liver tissue (0.4 vs 1.3 weight %), gut mucosa (0.3 vs 1.0 weight %), and tumor tissue (0.3 vs 0.8 weight %). Also, the DHA levels in the PUFA group were significantly higher than the control group: liver tissue (4.1 vs 7.5 weight %), gut mucosa (2.1 vs 3.7 weight %) and tumor tissue (1.9 vs 4.2 weight %).

CONCLUSIONS

This study suggests that administration of PUFA-enriched diets leads to increased incorporation of EPA and DHA not only in liver and gut mucosa tissue, but also in tumor tissue in patients with solid gastrointestinal tumors. Thus, preoperative administration of oral PUFA-enriched diets could have an impact on the postoperative inflammatory response after major abdominal surgery.

Abnormal regulation of serum lipid fatty acid profiles in short gut rats fed parenteral nutrition with lipid

Despite absence of essential fatty acid deficiency (EFAD), increases in arachidonic acid to linoleic acid ratios occur in serum phospholipid of patients treated with chronic total parenteral nutrition (TPN). The parenteral lipid component of TPN contains abundant linoleate; thus low phospholipid linoleate may reflect increased conversion to arachidonate. Arachidonic acid excess has been associated with a proinflammatory milieu through increased eicosanoid production and might contribute to the increases in inflammatory markers seen in home TPN patients. We investigated fatty acid metabolism in a rodent model of malabsorption. We hypothesized that short gut rats would metabolize parenteral lipid differently from intact rats. We performed laparotomy and 80% small bowel resection (or sham surgery) in rats. Sixteen sham and 16 short gut rats were randomly assigned to TPN with lipid or fat-free TPN. After 5 days, weight loss was similar in all groups. Analysis of serum phospholipids demonstrated that 20:3omega9 (eicosatrienoic acid) was relatively increased in fat-free TPN groups, irrespective of surgery type, as were distal very long chain omega3 class fatty acids, as anticipated. Uniquely, both nutrition (TPN/lipid v fat-free TPN) and surgery type (sham v short gut) were significant in determining arachidonic acid levels. Relatively elevated arachidonate occurred in both groups of fat-free rats, suggesting increased Delta6 and/or Delta5 desaturase activity, as expected. In contrast, giving TPN/lipid lowered arachidonate (suggesting appropriately downregulated desaturases) in sham animals, but not in short gut animals. Ratios of arachidonic and di-homo-gamma-linolenic to linoleic acids further suggested increased turnover of precursor omega6 to arachidonic acid in short gut rats given lipid compared with the other groups. These preliminary data show that intravenous (IV) lipid gave rise to serum lipid fatty acid profiles that differed in short gut and sham rats. The short gut rat may have a heightened hepatic desaturase activity, inappropriate for the quantity of linoleic acid provided parenterally. Therefore, the short gut rat is an appropriate model to study further arachidonic acid excess in home TPN patients.

Effects of dietary n-3 or n-6 fatty acids on interleukin-1beta-induced anxiety, stress, and inflammatory responses in rats

The present study demonstrated that an omega (n)-3 fatty acid, ethyl-eicosapentaenoic acid (ethyl-EPA), supplemented diet significantly attenuated the stress/anxiety behavior of rats in the "open field" and elevated plus maze, which was induced by subchronic intracerebroventricular administration of proinflammatory cytokine interleukin (IL)-1beta. Ethyl-EPA also reduced the rise in serum corticosterone induced by IL-1. The n-6 fatty acid ethyl-gamma-linolenic acid (ethyl-GLA) had little effect on the IL-1-induced changes in behavior and the corticosterone concentration. Following IL-1beta administration, ethyl-EPA reduced the elevated prostaglandin (PG) E2 secretion and increased the secretion of antiinflammatory cytokine IL-10 from whole blood cells. Ethyl-GLA showed a similar antiinflammatory effect to ethyl-EPA. By contrast, n-6 fatty acid arachidonic acid (AA) had no effect on the behavior, immune, and endocrine changes induced by IL-1. AA alone enhanced the basal inflammatory response, raised serum corticosterone concentrations, and induced anxiety behavior in the elevated plus maze. The reduced growth rates of rats following the administration of IL-1 was attenuated by ethyl-EPA, and to a greater extent by ethyl-EPA plus ethyl-GLA, but not by AA alone or in combination with ethyl-EPA. Thus, ethyl-EPA would appear to antagonise the endocrine, immune, and behavioral effects of subchronic IL-1 administration. Ethyl-GLA only antagonised IL-1-induced inflammatory changes, whereas AA caused an increase in the secretion of corticosterone and PGE2, and induced anxiety-like behavior without enhancing the effects of IL-1.

Nutritional supplementation with N-3 fatty acids and antioxidants in patients with Crohn's disease in remission: effects on antioxidant status and fatty acid profile

In patients with Crohn's disease (CD), malnutrition is frequently observed and is generally accepted to be an important issue. The aim of this study was to investigate the effects of 3 months of supplementation with a liquid formula containing either antioxidants (AO) or n-3 fatty acids plus AO on the antioxidant status and fatty acid profile of plasma phospholipids and adipose tissue, respectively, in patients with long-standing CD currently in remission. In a randomized, double-blind placebo-controlled study, CD patients received either placebo, AO, or n-3 fatty acids plus AO for 3 months in addition to their regular diet. In all, 25/37 CD patients completed the study. AO status was assessed by blood biochemical parameters. A statistical per-protocol analysis was performed. Serum concentrations of selenium, vitamin C, and vitamin E, the activity of superoxide dismutase and total antioxidant status were significantly (p < 0.05) increased after AO supplementation. Furthermore, compared with controls, serum concentrations of beta-carotene, selenium, and vitamin C and the activity of glutathione peroxidase (GPx) were significantly (p < 0.05) lower before supplementation; however, after AO supplementation these levels were not significantly different from controls (except for GPx). N-3 fatty acids plus AO supplementation significantly (p < 0.05) decreased the proportion of arachidonic acid, and increased the proportion of eicosapentanoic acid and docosahexanoic acid in both plasma phospholipids and adipose tissue. Supplementation with antioxidants improved antioxidant status in patients with CD in remission. In addition, supplementation with n-3 fatty acids plus antioxidants significantly changed the eicosanoid precursor profile, which may lead to the production of eicosanoids with attenuated proinflammatory activity. This study indicates that an immunomodulating formula containing n-3 fatty acids and/or AO may have the potential to play a role in the treatment of CD.

Dietary fatty acids and insulin resistance

High-fat diets have been associated with insulin resistance, a risk factor for both Type II diabetes and heart disease. The effect of dietary fat on insulin varies depending on the type of fatty acid consumed. Saturated fatty acids have been consistently associated with insulin resistance. On the other hand, medium and long-chain fatty acid intakes are associated with insulin sensitivity, as are high intakes of w3 fatty acids. Trans fatty acids appear to potentiate insulin secretion, at least in the short-term, to a greater degree than cis fatty acids. This may reflect chronic alterations in insulin sensitivity, although this remains to be tested. In summary, although it must be emphasized that all diets high in fat cause insulin resistance relative to high-carbohydrate diets, it appears that dietary saturated, short-chain, and w6 fatty acids have the most deleterious effects on insulin action.

Conditionally essential fatty acid deficiencies in end-stage liver disease

Patients with end-stage liver disease (ESLD) manifest a wide variety of functional abnormalities that lead eventually to their death. Such patients also often have low levels of long-chain polyunsaturated fatty acids (PUFA) of carbon length 20 or greater in plasma total lipids, triacylglycerols, cholesterol esters, and phospholipids. We hypothesize that, due to hepatic damage, there is an impairment in de novo synthesis of very long-chain (20-22) carbon PUFA from their essential fatty acid 18 carbon dietary precursors that normally takes place principally in the liver. This results in a "conditional" essential fatty acid deficiency that may, in fact, be responsible for some of the pathophysiologic effects in ESLD. We propose that direct supplementation with very long-chain PUFA will provide a unique advantage in the correction of this "conditional" essential fatty acid deficiency in patients with ESLD and lead to improvements in their clinical condition.