Plasma polyunsaturated fatty acid pattern in active inflammatory bowel disease

Altered lipid profile, lipoprotein composition, and oxidant and antioxidant status in pediatric Crohn disease

BACKGROUND

Growing evidence supports a role for peroxidation in the pathogenesis of Crohn disease (CD). The activation of inflammatory cells, the release of their mediators, and the excessive production of free radicals may affect circulating lipids.

OBJECTIVE

We examined the lipid profile, lipoprotein composition, and oxidant-antioxidant status of children with CD.

DESIGN

We studied 22 pediatric CD patients and 10 healthy control subjects.

RESULTS

The proportion of saturated and monounsaturated fatty acids in plasma of CD patients was higher but that of polyunsaturated fatty acids was lower than in control subjects. This resulted in higher ratios in CD patients of palmitoleic acid to linoleic acid (P < 0. 05) and of eicosatrienoic acid to arachidonic acid (P < 0.04), 2 established indexes of essential fatty acid deficiency. Hypocholesterolemia was noted in CD patients as a result of lower LDL-cholesterol concentrations than in control subjects (P < 0.02). Plasma apolipoproteins B (P < 0.02) and A-I (P < 0.02) were also lower in CD patients, whereas plasma triacylglycerols were higher (P < 0.005). Lipoprotein composition was altered in CD patients, with relative triacylglycerol depletion and protein enrichment in VLDL. In contrast, intermediate-density lipoprotein of CD patients was characterized by an increased percentage of triacylglycerol and protein (P < 0.005) and a reduced proportion of phospholipids (P < 0. 01). Additional abnormalities were observed in the chemical distribution of HDL(2) and HDL(3) moieties. Lipid peroxidation was documented by higher plasma malondialdehyde concentrations in CD patients (P < 0.05), accompanied by lower retinol concentrations (P < 0.02).

CONCLUSION

Disturbances in the lipid profile, in lipoprotein concentrations and composition, and in oxidant-antioxidant status occur in CD patients.

Fat intake and fatty acid profile in plasma phospholipids and adipose tissue in patients with Crohn's disease, compared with controls

OBJECTIVES

Fatty acid metabolism is involved in the immune response and inflammation processes in patients with Crohn's disease (CD). Fatty acid changes may be relevant to the clinical course of the disease. The aim of this study was to compare the qualitative and quantitative fat intake and fatty acid composition of plasma phospholipids and adipose tissue in a defined population of CD patients with those in matched controls.

METHODS

Dietary fat intake and fatty acid profile of plasma phospholipids and adipose tissue were assessed in two patient populations: 20 patients with recently diagnosed CD and 32 patients with longstanding (> 10 yr) CD clinically in remission, matched for age and gender with healthy controls.

RESULTS

We observed no significant differences in quantitative or qualitative fat intake between CD patients and controls. Percentages of linoleic acid and alpha-linolenic acid in plasma phospholipids or adipose tissue were not significantly different between patients and controls. However, we observed a significantly (p < 0.05) lower percentage of the sum of the n-3 fatty acids, with significantly (p < 0.01) higher levels of clupanodonic acid (22:5n-3) and significantly (p < 0.05) lower levels of docosahexaenoic (22:6n-3) and arachidonic acid (20:4n-6). The aberrant fatty acid profile was more evident in patients with longstanding CD than in patients with recently diagnosed CD.

CONCLUSION

The aberrant fatty acid profile found in these CD patients is a result of altered metabolism rather than of essential fatty acid malabsorption. The reported findings may be important in the pathophysiology of CD and hence in the choice of fatty acids to be used when therapeutic supplementation is considered in CD patients.

Plasma and mucosal fatty acid pattern in colectomized ulcerative colitis patients

Patients with inflammatory bowel disease (IBD) have increased plasma n3 polyunsaturated fatty acids (PUFAs), which in ulcerative colitis (UC) patients persists six months after colectomy, suggesting a primary abnormality in fatty acid (FA) metabolism in IBD. This finding needed to be confirmed in a larger series of UC long-term colectomized patients. We aimed to assess the plasma FA pattern in UC colectomized patients with either Brooke's ileostomy (UC-BI) or ileal pouch anal anastomosis (UC-IPAA) and the mucosal FA pattern in the ileal reservoir of the UC-IPAA patients. Plasma FAs were assessed in 63 UC colectomized patients (31 with BI and 32 with IPAA) and 30 controls. In 26 UC-IPAA (8 with pouchitis and 18 without pouchitis) and in 13 healthy controls gut mucosal FAs were also investigated. FAs were detected by capillary column gas-liquid chromatography. Increased levels of saturated fatty acids (SFAs) and decreased percentages of monounsaturated fatty acids (MUFAs) were observed in both groups of patients. There were no changes in plasma n3 and n6 PUFAs. The mucosal FA pattern of the ileal reservoir consisted of increased long-chain PUFAs, specially n6 PUFA, and a decrease of their essential precursors. High percentages of SFAs and low percentages of MUFAs were also seen. The plasma FA profile previously described in IBD is not observed long-term after colectomy in UC, suggesting that it is related with the presence of inflamed intestine. High concentrations of SFAs and decreased percentages of MUFAs might represent early events in disturbed FA metabolism in IBD. The changes in FAs of the ileal reservoir, which closely resemble those found in human and experimental IBD, probably represent a common pattern of intestinal inflammation.

Serum n3 polyunsaturated fatty acids are depleted in Crohn's disease

To determine fatty acid patterns in Crohn's disease, we measured various serum fatty acids by gas chromatography in 20 patients with the disease and compared them with those in 18 healthy controls. All the patients had been free from any nutritional supplementation during preceding six months or had no history of intestinal resection. Eight of the patients were affected in the small bowel only, three in the large bowel only, and the remaining nine in both the small and large bowel. Both serum concentrations and percentages of C20:4n6, C20:5n3, C22:0, C22:6n3, total n3 polyunsaturated fatty acids, and total polyunsaturated fatty acids were lower in the patients than in the controls. Both essential fatty acids (C18:2n6, C18:3n3) and C20:3n9 levels were not different between the two groups. Among nine fatty acids that correlated with the Crohn's disease activity index, C20:5n3 and total n3 polyunsaturated fatty acids showed the most significant negative correlations. These findings suggest that essential fatty acid deficiency rarely occurs in Crohn's disease and also that n3 polyunsaturated fatty acids may be relevant to the activity of the disease.

Polyunsaturated fat in the diet may improve intestinal function in patients with Crohn's disease

To investigate the effect of increasing dietary polyunsaturated fat intake on fat absorption in Crohn's patients, normal subjects and subjects with inactive Crohn's disease consumed a high polyunsaturated to saturated fat ratio diet. Subjects participated in breath tests before and after six months of a high polyunsaturated to saturated (P/S) fat ratio diet to measure their response to [1-13C] 10:0 and [1-13C] 16:0 ingested with a test meal. Whole body absorption-oxidation of C10:0 was not affected by the diet treatment. Before diet treatment, whole body absorption-oxidation of C16:0 in Crohn's patients was 80% of that observed for control subjects. After consuming a high polyunsaturated to saturated fatty acid ratio diet, subjects increased oxidation of C16:0 by 85% compared to before the diet treatment period. It is concluded that (1) absorption of labelled C16:0 from a test meal is reduced in Crohn's patients, and (2) consumption of a high polyunsaturated to saturated fatty acid ratio diet improves the utilization of dietary C16:0 by Crohn's patients.

Biochemical tests in diseases of the intestinal tract: their contributions to diagnosis, management, and understanding the pathophysiology of specific disease states

Biochemical testing plays a major role in the complete evaluation of patients with suspected or established intestinal disease. We have classified these tests according to the medium in which they are performed: breath tests, including isotopic and nonisotopic tests, fecal tests, urine tests, serum tests, tissue tests, and other tests. The principles of various tests are outlined, and the role of each test in the evaluation of particular gastrointestinal disorders is discussed.

Omega-3 fatty acids and low carbohydrate diet for maintenance of remission in Crohn's disease. A randomized controlled multicenter trial. Study Group Members (German Crohn's Disease Study Group)

BACKGROUND

There is no established therapy for maintaining remission in patients with Crohn's disease. Following different suggestions from the literature, two potential interventions for maintaining remission were tested against placebo, using either 5 g/day of a highly concentrated omega-3 fatty acid compound or a carbohydrate-reduced diet (84 g/day).

METHODS

A total of 204 patients were recruited after they had had an acute relapse. After remission (CDAI < or = 150) was attained with steroid therapy, patients were randomized to receive either omega-3 fatty acids (n = 70), placebo (n = 65), or diet (n = 69). Low-dose prednisolone was given to all patients for the first 8 weeks of intervention. CDAI and an acute-phase protein (CRP) were used as criteria for a relapse.

RESULTS

The proportion of patients without relapse within a year were similar in the placebo and active treatment group (intention-to-treat analysis: placebo, 30%; active treatment, 30%; protocol-adhering patients, 29% versus 28%). Patients did gain benefit (53%; p = 0.023) for as long as they maintained the diet. However, intention-to-treat analysis (diet group, 40%) did not show a noticeable difference when compared with placebo.

CONCLUSIONS

Omega-3 fatty acids did not show an effect on extending the remission in Crohn's disease. For the diet patients the question remains whether the noncompliant patients dropped out early because they sensed a relapse approaching or whether their condition deteriorated because they failed to comply with the diet.

Nutritional considerations and management of the child with inflammatory bowel disease

Crohn's disease and ulcerative colitis are chronic inflammatory diseases of the bowel often associated with significant malnutrition, particularly in children because of increased nutrient demands due to growth. We discuss the increasingly prominent role of nutritional support in inflammatory bowel disease (IBD). Issues that are addressed include the etiology of malnutrition in IBD, assessment and monitoring of patient nutritional status and the use of nutrition in the management of growth failure and as primary medical therapy.

Prevalence of essential fatty acid deficiency in patients with chronic gastrointestinal disorders

Patients with chronic intestinal disorders causing malabsorption, nutritional losses through diarrhea, or catabolic illness would be expected to have essential fatty acid (EFA) deficiency (EFAD), but such deficiency has not been demonstrated in patients treated in accordance with the prevailing standard of care. We studied plasma fatty acid patterns of 56 reference or control subjects and 47 patients with chronic intestinal disorders (mostly Crohn's disease) using high-resolution capillary column gas-liquid chromatography. Patients exhibited a shift in fatty acid metabolism similar to that previously shown to be associated with EFAD. Compared with control subjects, patients had (1) decreased polyunsaturated fatty acid (PUFA) levels (43.7% v 50.4%, P < .0001), (2) increased monounsaturated fatty acid (MUFA) levels (25.8% v 22.0%, P < .0001), (3) higher ratios of mead (20:3 omega 9) to arachidonic (20:4 omega 6) acid (0.020 v 0.013, P < .04), and (4) lower concentrations of total (214 v 284 mg/dL, P < .01), saturated ([SFA] 63 v 75 mg/dL, P < .001), MUFA (56 v 63 mg/dL, P < .001), and PUFA (93 v 143 mg/dL, P < .001). Patients had metabolic shifts toward increased production of MUFA and an increased ratio of derivatives to precursors of omega 6 fatty acids, shifts that occur when cells are EFA-deficient. More than 25% of the patients had biochemical evidence of EFAD according to at least one criterion. Optimal diagnosis requires a concurrent evaluation of concentrations of fatty acids in plasma and in lipoproteins (percent fatty acids). On indices of EFA status that depend on percents, ratios, or concentrations of fatty acids or on the production of abnormal fatty acids, the patients were between patients with severe whole-body EFAD and healthy subjects, a state referred to as absolute EFA insufficiency. Patients with chronic intestinal disease should be evaluated for likely EFA deficiencies and imbalances, and treated with substantial amounts of supplements rich in EFAs, such as oral vegetable and fish oils, or intravenous lipids if necessary.

Ileal and colonic fatty acid profiles in patients with active Crohn's disease

In patients with active Crohn's disease and in a control group the fatty acid profiles in the whole lipid fraction of ileal and colonic mucosal biopsy specimens were determined by capillary gas chromatography. The biopsy specimens in Crohn's disease patients were taken from the inflamed terminal ileum as well as from the inflamed and macroscopically normal colon. Compared with controls the fatty acid distribution in the inflamed ileal mucosa was significantly characterised by (a) a decrease of 18:2 n6 and 18:3 n3 accompanied by a substantial increase of the highly polyunsaturated fatty acids 20:4 n6, 22:4 n6, and 22:6 n3 and (b) a higher unsaturation index of total fatty acids compared with controls. These changes were similar in the inflamed colon. Additionally, both the inflamed and the macroscopically normal colonic mucosa showed an increase of saturated (18:0) and a decrease of monounsaturated fatty acids (18:1 n9). Fatty acid profiles of ileum and colon showed side variations in controls, but not in the Crohn's disease group. These data suggest that in Crohn's disease changes in the distribution of polyunsaturated fatty acids seem to be the general feature of inflamed mucosa in small and large intestine. Results further suggest that colonic fatty acid metabolism in Crohn's disease is altered by degrees, showing changes in saturated and monounsaturated fatty acids as an additional, primary event.

Enteral nutrition as primary therapy in Crohn's disease

The developments in enteral feeding for Crohn's disease in the past decade are critically reviewed. The advent of amino acid based chemically defined elemental diets signalled the end of 'total bowel rest' in the management of these patients. Subsequently, controlled clinical trials showed that elemental diets were as effective as corticosteroids in inducing clinical remission in patients with acute exacerbations of Crohn's disease. The later use of peptide based elemental diets, in Crohn's disease produced somewhat conflicting results. The initial uncontrolled studies suggest that polymeric whole protein diets might also be effective in the management of acute exacerbations of the disease, casting in turn doubts concerning the role of dietary antigens in the pathogenesis of Crohn's disease. Results of controlled studies comparing the use of elemental and polymeric diets as primary therapy in Crohn's disease have, however, also produced conflicting results. The results of one recent controlled trial in which the use of polymeric diet was compared with that of corticosteroids does, however, suggest that these diets may have a primary therapeutic effect in Crohn's disease. An analysis of the composition of some of the enteral diets used in different trials suggest that the effectiveness of enteral diets in treating active Crohn's disease might relate more to their fat than nitrogen composition. A hypothesis is proposed that the effectiveness of enteral nutrition in the primary therapy of acute exacerbations of Crohn's disease occurs because the successful diets used contain insufficient precursors for arachidonate derived eicosanoid synthesis.

Abnormal plasma polyunsaturated fatty acid pattern in non-active inflammatory bowel disease

An abnormal plasma polyunsaturated fatty acid pattern (PUFA) (increased n3 and decreased n6 PUFA) has been reported in active inflammatory bowel disease (IBD). The possibility of a primary defect in the PUFA metabolism in IBD was hypothesised. The aim of this study was to assess plasma PUFA pattern in inactive inflammatory bowel disease and to ascertain whether patients who had had a colectomy and who were suffering from ulcerative colitis have a similar PUFA pattern than those patients with non-active ulcerative colitis and who had not had a colectomy. Plasma fatty acids were analysed by semi-capillary column gas-liquid chromatography in three groups of patients with inactive IBD (24 patients with inactive ulcerative colitis who had not had a colectomy, 15 patients with ulcerative colitis who had had a colectomy, and 27 patients with Crohn's disease). Plasma concentration and percentage of C22:6n3 and unsaturation index were significantly higher in patients with inactive ulcerative colitis without a colectomy and the Crohn's disease group (p < 0.0001) than in controls. Plasma concentration and percentage of C22:6n3 and the unsaturation index remained significantly higher, in both the operated and non-operated ulcerative colitis patients when compared with controls (p < 0.0001). These results suggest that in inactive IBD, an increased PUFA biosynthesis might be the cause of the high values of n3 compounds. These findings although seen in active disease, are more noticeable in remission because of the lack of artefactual factors (malnutrition, steroids, inflammation). In addition, persistence of high values in both groups of ulcerative colitis patients--that is, those who had had a colectomy and those who had not suggests the existence of a primary abnormality in the PUFA metabolism in IBD.

Polymeric enteral diets as primary treatment of active Crohn's disease: a prospective steroid controlled trial

Thirty two patients with active Crohn's disease were included in a controlled randomised trial to determine the efficacy and safety of polymeric enteral nutrition compared with steroids, to achieve and maintain clinical remission. The polymeric diet was administered through a fine bore nasogastric tube by continuous, pump assisted infusion (2800 (SEM 120) kcal/day). The steroid group received 1 mg/kg/day of prednisone. Both treatments were effective in inducing clinical remission: 15 of the 17 patients given steroids and 12 of the 15 patients assigned to the polymeric diet went into clinical remission (defined by a Van Hees index < 120) within four weeks of treatment. The percentage reduction of the Van Hees index was 34.8 (4.9)% for steroids and 32.3 (5)% for enteral nutrition (mean difference 2.5%; 95% CI--11.8% to +16.8%). Mean time elapsed to achieve remission was similar in both groups (2.0 (1) v 2.4 (1.2) weeks). Tolerance of the enteral diet was excellent. Four patients in the steroid group had mild complications attributable to this treatment. Ten patients (66.6%) in the steroid group and five (41.6%) in the enteral nutrition group relapsed within a year of discharge, but no differences were found in the cumulative probability of relapse during the follow up period. These results suggest that polymeric enteral nutrition is as safe and effective as steroids in inducing short term remission in active Crohn's disease.