linoleic-acid and Malabsorption-Syndromes

Pancreatic enzyme replacement therapy frequently fails to correct intestinal fat malabsorption completely in cystic fibrosis (CF) patients. The reason for this failure is unknown.. We investigated whether fat malabsorption in CF patients treated with pancreatic enzymes is caused by insufficient lipolysis of triacylglycerols or by defective intestinal uptake of long-chain fatty acids.. Lipolysis was determined on the basis of breath 13CO2 recovery in 10 CF patients receiving pancreatic enzyme replacement therapy after they ingested 1.3-distearoyl,2[1-13C]octanoyl glycerol ([13C]MTG). Intestinal uptake of long-chain fatty acids was determined by analyzing plasma [13C]linoleic acid ([13C]LA) concentrations after patients ingested [13C]LA. For 3 d, dietary intakes were recorded and feces were collected.. Fecal fat excretion ranged from 5.1 to 27.8 g/d (mean+/-SD: 11.1+/-7.0 g/d) and fat absorption ranged from 79% to 93% (89+/-5%). There was no relation between breath 13CO2 recovery and dietary fat absorption (r = 0.04) after ingestion of [13C]MTG. In contrast, there was a strong relation between 8-h plasma [13C]LA concentrations and dietary fat absorption (r = 0.88, P < 0.001).. Our results suggest that continuing fat malabsorption in CF patients receiving enzyme replacement therapy is not likely due to insufficient lipolytic enzyme activity, but rather to incomplete intraluminal solubilization of long-chain fatty acids, reduced mucosal uptake of long-chain fatty acids, or both.

Topics: Adolescent; Child; Cystic Fibrosis; Dietary Fats; Fatty Acids; Feces; Female; Humans; Intestinal Absorption; Intestinal Mucosa; Linoleic Acid; Lipolysis; Malabsorption Syndromes; Male; Nutrition Policy; Pancreatic Extracts; Triglycerides

Topics: Cystic Fibrosis; Dietary Fats; Humans; Intestinal Absorption; Linoleic Acid; Malabsorption Syndromes; Pancreatic Extracts

Fatty acids were measured by gas chromatography in lipid extracts of plasma and tissues obtained from three categories of 46 patients with cystic fibrosis. Low levels of the major essential fatty acid linoleate were found in plasma total lipids of patients who had malabsorption but not in those without evidence of steatorrhea. Circulating arachidonic acid was only slightly decreased, and the unusual triene reflecting pathologically altered fatty acid metabolism (20:3 omega 9) was generally not detected, nor was the triene/tetraene ratio abnormal except for in two patients. There was no correlation between plasma linoleate and age, clinical severity score, or vitamin E status. Decreased linoleate did correlate with two indices of malabsorption, namely plasma carotene (r = 0.64) and fecal fat excretion (r = 0.76). Our data therefore indicate that the abnormality in linoleate is associated with (secondary to) malabsorption of dietary fat despite pancreatic enzyme replacement therapy and consumption of a regular diet. The frequency of this alteration was determined to be quite high in 40 patients with steatorrhea, 85% of whom showed values below the lower limit of normal for plasma linoleate. It was of interest to find markedly decreased levels of linoleate in adipose tissue, cardiac muscle, and lung and lesser reductions in liver and psoas muscle taken at autopsies. Tissue arachidonic acid percentage was normal, however, and 20:3 omega 9 was rarely present. Thus, the physiological significance of this common abnormality in CF patients with malabsorption remains to be determined.

Topics: Adipose Tissue; Adult; Arachidonic Acid; Arachidonic Acids; Child; Chromatography, Thin Layer; Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Fatty Acids; Fatty Acids, Monounsaturated; Humans; Linoleic Acid; Linoleic Acids; Lipids; Malabsorption Syndromes; Oleic Acid; Oleic Acids; Palmitic Acid; Palmitic Acids; Vitamin E; Vitamin E Deficiency

Intestinal fat absorption was examined in rats with CCl4-induced liver cirrhosis. Marked lymphangiectasia of the small intestine was observed in rats after CCl4 was given subcutaneously biweekly for 10--12 weeks. Intestinal epithelial uptake of linoleic acid administered in the loop was not impaired, but accumulation of lipid droplets in the intestinal epithelial cells and disturbed lymphatic transport of absorbed fat were observed in these rats. These data suggest that lymphostasis of the intestine may play an important role in fat malabsorption in liver cirrhosis.

Topics: Animals; Carbon Tetrachloride; Intestine, Small; Linoleic Acid; Linoleic Acids; Lipids; Liver Cirrhosis; Lymphatic System; Malabsorption Syndromes; Male; Rats; Rats, Inbred Strains