gamma-linolenic-acid and Gastrointestinal-Hemorrhage

The effects of dietary linoleic acid, gamma-linolenic acid and marine fatty acids on the development of aspirin-induced gastric hemorrhage and the distribution of liver glycerophospholipid fatty acids in fat-deficient growing rats were studied. Aspirin (100 mg/day)-treated and nontreated rats were fed for 7 days, a mixed diet of 2.5% safflower oil and 7.5% hydrogenated coconut oil (SFO/HCO) or 7.5% fish oil (SFO/FO), or 2.5% gamma-linolenate concentrate and 7.5% fish oil (GLA/FO). Gastric hemorrhage was induced in animals by aspirin treatment to various extents. It was not affected by FO feeding, but was significantly alleviated by GLA feeding. Aspirin treatment reduced the proportions of 20:4n-6 in liver phosphatidylcholine. FO feeding (in SFO/FO and GLA/FO rats) further reduced the 20:4n-6 level and replaced it by n-3 fatty acids. GLA feeding, on the other hand, elevated the proportion of 20:4n-6. As a result, the reduction of 20:4n-6 by fish oil feeding, was less significant in GLA/FO rats than in SFO/FO rats. The degree of gastric hemorrhage appeared to relate negatively to the levels of 20:4n-6 in liver phosphatidylcholine, and to the sum of 20:4n-6 and 20:5n-3 when FO was included in the diet. It is suggested that long-chain polyunsaturated fatty acids (20:4n-6 and 20:5n-3) per se in addition to being precursors of prostaglandins, may also affect the development of gastric hemorrhage, possibly by modulating the permeability of cell membranes in the gastric mucosa.

Topics: Animals; Aspirin; Dietary Fats; Fatty Acids, Unsaturated; Fish Oils; gamma-Linolenic Acid; Gastrointestinal Hemorrhage; Linoleic Acid; Linoleic Acids; Linolenic Acids; Liver; Male; Phosphatidic Acids; Phosphatidylcholines; Phosphatidylethanolamines; Rats; Rats, Inbred Strains

The effects of feeding with gamma-linolenic acid (GLA) in comparison with linoleic acid on aspirin-induced gastric hemorrhage were studied in the rat. Gastric damage was examined macroscopically and histologically. Intragastric administration of 100 mg aspirin daily for 4 weeks produced hemorrhage in 3 of 8 rats receiving a linoleic-acid-enriched diet, but none in 8 rats receiving GLA-enriched diet. The levels of linoleic acid in plasma and liver phospholipids were significantly increased, whereas those of arachidonic acid (AA) were reduced in plasma and liver phospholipids of aspirin-treated animals fed linoleic acid. Similar, more pronounced changes occurred in those animals with hemorrhage. The reduced ratios of arachidonate/linoleate suggest that fatty acid desaturation in these animals was depressed. Treatment with GLA prevented these changes. Our results demonstrated that GLA could protect the gastric mucosa from aspirin-induced damage by bypassing the depressed delta-6-desaturation and thus providing a precursor for the synthesis of AA and prostaglandins.

Topics: Animals; Arachidonic Acids; Aspirin; Fatty Acids; Female; gamma-Linolenic Acid; Gastric Mucosa; Gastrointestinal Hemorrhage; Linoleic Acid; Linoleic Acids; Linolenic Acids; Liver; Phospholipids; Rats; Rats, Inbred Strains

Prostaglandins protect the gastric mucosa in animals, but the evidence of an effect independent of pH changes in man is not overwhelming. Gastrointestinal bleeding because of non-steroidal anti-inflammatory drugs is a major clinical problem, which we have investigated in a model system measuring bleeding rates caused by short-term administration of aspirin. Of the various strategies tested, only those that elevated intra-gastric pH reduced aspirin-induced bleeding.

Topics: Animals; Anti-Inflammatory Agents; Aspirin; Cattle; Enprostil; Fatty Acids, Essential; Fatty Acids, Unsaturated; Female; gamma-Linolenic Acid; Gastrointestinal Hemorrhage; Humans; Linoleic Acid; Linoleic Acids; Lysine; Male; Milk; Oenothera biennis; Plant Oils; Prostaglandins E, Synthetic; Ranitidine