triolein and Ischemia

The ability of the small intestine to absorb and transport lipid into lymph is markedly reduced 24 h after a 10-min total occlusion of the superior mesenteric artery (SMA). The aim of this study was to define the role of neutrophils in the ischemia-reperfusion (I/R)-induced decrement in lipid absorption. A lipid test meal containing 40 mumol of radioactive triolein was infused intraduodenally at 3 ml/h for 8 h, and radioactive lipid output in lymph was monitored during lipid infusion in intestinal lymph fistula rats. Animals rendered neutropenic with antineutrophil serum (ANS) did not exhibit the reduction in lipid absorption and transport in lymph normally observed 24 h after I/R. This protective effect of ANS was specifically related to the reduction in the number of neutrophils in the intestinal mucosa. The amount of radioactive lipid detected in the liver of untreated rats was significantly higher than in control rats, suggesting an increased portal transport of infused radioactive lipid. Neutropenia reduced the liver lipid level toward the control value. The intestinal blood flow response to SMA occlusion was not altered by neutropenia. Our results suggest that neutrophils play an important role in the mucosal dysfunction associated with ischemia-reperfusion.

Topics: Animals; Intestinal Absorption; Intestinal Mucosa; Intestine, Small; Ischemia; Lymph; Male; Mesenteric Arteries; Muscle, Smooth; Neutrophils; Rats; Rats, Inbred Strains; Regional Blood Flow; Reperfusion Injury; Triolein

The purpose of this study was to assess intestinal function after ischemia-reperfusion (I/R). In two groups of intestinal lymph fistula rats (experimental), the superior mesenteric artery (SMA) was isolated and occluded for 10 min. In the remaining two groups (controls), the SMA was isolated but not occluded. Twenty-four or forty-eight hours after I/R, a lipid test meal containing radioactive triolein was infused at 3 ml/h for 8 h. Radioactive lipid in lymph, lumen, intestinal wall, portal and systemic blood, epididymal fat pads, and liver was determined. Lymph radioactive lipid output was markedly depressed in the 24-h experimental rats compared with the other three groups, and this deficiency was restored 48 h after I/R. This reduction in lipid output in lymph appeared to be the result of an increased portal transport of the infused radioactive lipid rather than a deficiency of digestion or absorption of infused triolein. We have further validated the markedly increased portal transport of radioactive lipid after I/R by using Triton WR-1339, which blocks peripheral metabolism of hepatic very low-density lipoproteins (VLDL). When Triton WR-1339 was introduced in 24 experimental and control animals, the experimental rats accumulated significantly more radioactive lipid (12-14% of infused lipid) than the control animals (2-3% of infused lipid), indicating a marked increase in portal transport of radioactive lipid, which was taken up by the liver and then resecreted into circulation as VLDL. Thus intestinal lipid absorption is sensitive to the deleterious effects of ischemia followed by reperfusion, and therefore it may be used as a functional assessment of the small intestine after I/R-induced injuries.

Topics: Adipose Tissue; Animals; Dietary Fats; Digestion; Intestinal Absorption; Intestine, Small; Ischemia; Kinetics; Lipoproteins, VLDL; Liver; Lymph; Male; Mesenteric Arteries; Portal System; Rats; Rats, Inbred Strains; Regional Blood Flow; Reperfusion; Triolein

The simultaneous use of 131I-triolein and 75Se-triether, a nonabsorbable marker, in a single oral dose to estimate fat absorption from incomplete fecal collections was tested in rats with and without induced steatorrhea. The results in normal rats showed that analysis of single stool samples allows a valid estimate of fat absorption as defined by the balance study based on the total fecal recovery of 131I. However, in the few normal rats with poor absorption, the absorption values from successively excreted stools showed a tendency to increase. Similar findings were obtained from biliary fistula rats with marked steatorrhea. No evidence of different intestinal transit rates of test fat and marker was observed in bile-diverted rats, thus suggesting that the observed inconsistency in fat absorption values from different stool specimens reflects intraprandial differences in the absorption of fat. Studies on rats subjected to intestinal ischemia do not support the suggestion of others that separation of fat and triether will occur if a mucosal defect is involved as the cause of fat malabsorption. It is concluded that this dual isotope technique may be of value in the clinical estimation of fat absorption, as it offers important technical advantages over conventional fat balance studies.

Topics: Animals; Biliary Fistula; Ethers; Feces; Intestinal Absorption; Intestines; Iodine Radioisotopes; Ischemia; Lipid Metabolism; Radioisotopes; Rats; Selenium; Triolein

Topics: Animals; Carbon; Female; Glucose; Intestinal Diseases; Ischemia; Kidney; Liver; Lung; Macrophages; Mononuclear Phagocyte System; Organ Size; Phagocytosis; Pulmonary Edema; Rats; Shock; Shock, Septic; Spleen; Surface-Active Agents; Triolein

Topics: Animals; Celiac Artery; Celiac Disease; Dogs; Iodine Isotopes; Ischemia; Mesenteric Arteries; Rats; Research; Triolein; Vascular Diseases; Xylose