linoleic-acid and Pancreatitis

Pancreatic oxidative stress with depletion of pancreatic glutathione is an early feature in all tested models of acute pancreatitis, and sooner or later the problem extends to the lung, irrespective of disease severity, whether toward spontaneous recovery or death from multisystem organ failure. We, therefore, sought evidence of oxidative stress in the human disease by analyzing admission blood samples. We found it from high concentrations of oxidatively altered linoleic acid in serum and vitamin C in plasma (p < 0.001 vs controls or a group of other acute abdominal crises where the proportion of patients with admission Apache II scores < or > 8 was similar). These changes were accompanied by subnormal levels of ascorbic acid in plasma (p < 0.001); selenium (p < 0.001), beta-carotene (p < 0.001), and alpha-tocopherol in serum (p = 0.005 for its molar ratio to cholesterol). Paradoxically, the plasma concentration of S-adenosylmethionine was elevated (p = 0.02), suggesting that this proximate bioactive metabolite of the essential amino acid had backtracked because its intracellular metabolism down the methionine trans-sulfuration pathway toward glutathione synthesis was disrupted. The aberrations transcended putative etiological factor, duration of symptoms, or disease severity. We conclude: (1) that oxidative stress has pervaded the vascular compartment by the time of admission in patients with acute pancreatitis, and, (2) that blood micronutrient antioxidant profiles at this stage are consistent not only with compromised intracellular capacity to synthesize/refurbish glutathione, but also vulnerability of intra- and extracellular lipid targets.

Topics: Acetylcysteine; Acute Disease; Adolescent; Adult; Aged; Aged, 80 and over; Analysis of Variance; Antioxidants; Discriminant Analysis; Free Radical Scavengers; Humans; Linoleic Acid; Linoleic Acids; Middle Aged; Oxidative Stress; Pancreatitis; S-Adenosylmethionine

The usefulness of micronutrient antioxidant therapy for recurrent (non-gallstone) pancreatitis has recently been endorsed by a 20-week double-blind double-dummy cross-over trial in 20 patients. Treatment was delivered as two types of tablets, providing daily doses of 600 micrograms organic selenium, 9000 i.u. beta-carotene, 0.54 g vitamin C, 270 i.u. vitamin E and 2 g methionine. We report antioxidant profiles in blood samples collected before entry, at the cross-over stage and upon completion of trial. Baseline serum concentrations of selenium, beta-carotene and vitamin E in the patients were significantly lower than in healthy controls, were unaltered by placebo and normalized by active treatment, but reverted to basal values in the subgroup that received placebo subsequently. The baseline serum concentration of a free radical marker--the 9-cis, 11-trans isomer of linoleic acid--was significantly higher in the patients than in controls, fell inexplicably in the placebo phase and fell further upon active treatment. Discriminant analysis eliminated the overlap in free radical marker and selenium concentrations between control sera on the one hand and baseline or post-placebo samples from the patients on the other: antioxidant treatment normalized the relationship between these biochemical parameters. Subnormal baseline serum levels of S-adenosylmethionine drifted downwards upon active treatment whereas a sharp rise was noted when a relapse of pancreatitis occurred during the placebo phase. The results confirm that adequate exposure to antioxidants in the active treatment phase was associated with amelioration of oxidative stress, and that there was no residual effect 10 weeks after switching over to placebo treatment. Furthermore, the paradoxical behaviour of S-adenosylmethionine may imply that the beneficial effect of micronutrient antioxidants in recurrent pancreatitis is linked with preservation of the methionine trans-sulfuration pathway in pancreatic acinar cells.

Topics: Acute Disease; Adolescent; Adult; Aged; Antioxidants; Chronic Disease; Double-Blind Method; Female; Free Radicals; Glutathione Peroxidase; Humans; Linoleic Acid; Linoleic Acids; Male; Middle Aged; Pancreatitis; S-Adenosylmethionine; Selenium

Acute lipolysis of visceral fat or circulating triglycerides may worsen acute pancreatitis (AP)-associated local and systemic injury. The pancreas expresses pancreatic triacylglycerol lipase (PNLIP), pancreatic lipase-related protein 2 (PNLIPRP2), and carboxyl ester lipase (CEL), which may leak into the visceral fat or systemic circulation during pancreatitis. We, thus, aimed to determine the pancreatic lipase(s) regulating lipotoxicity during AP. For this AP, associated fat necrosis was analyzed using Western blot analysis. Bile acid (using liquid chromatography-tandem mass spectrometry) and fatty acid (using gas chromatography) concentrations were measured in human fat necrosis. The fat necrosis milieu was simulated in vitro using glyceryl trilinoleate because linoleic acid is increased in fat necrosis. Bile acid requirements to effectively hydrolyze glyceryl trilinoleate were studied using exogenous or overexpressed lipases. The renal cell line (HEK 293) was used to study lipotoxic injury. Because dual pancreatic lipase knockouts are lethal, exocrine parotid acini lacking lipases were used to verify the results. PNLIP, PNLIPRP2, and CEL were increased in fat necrosis. Although PNLIP and PNLIPRP2 were equipotent in inducing lipolysis and lipotoxic injury, CEL required bile acid concentrations higher than in human fat necrosis. The high bile acid requirements for effective lipolysis make CEL an unlikely mediator of lipotoxic injury in AP. It remains to be explored whether PNLIP or PNLIPRP2 worsens AP severity in vivo.

Topics: Animals; Fat Necrosis; Gene Knockdown Techniques; HEK293 Cells; Humans; Intra-Abdominal Fat; Linoleic Acid; Lipase; Male; Mice; Pancreatitis

To evaluate the generation of halogenated fatty acids in the areas of fat necrosis during acute pancreatitis and to evaluate the effects of these molecules on the ensuing inflammatory process.. Lipid mediators derived from adipose tissue have been implicated in the progression of acute pancreatitis, although their precise role remains unknown.. Acute pancreatitis was induced in rats by intraductal infusion of 3.5% sodium taurocholate. Fatty acid chlorohydrins (FA-Cl) were measured in adipose tissue, ascitic fluid, and plasma by mass spectrometry. Chlorohydrins were also instilled in the rats' peritoneal cavity, and their effects on peritoneal macrophages activation and in systemic inflammation were evaluated. Finally, they have also been measured in plasma from human patients with acute pancreatitis.. Induced acute pancreatitis results in a substantial release not only of free fatty acids but also of the chlorohydrins of both oleic and linoleic acids from adipose tissue. In plasma, only the chlorohydrin of oleic acid was detected. Administration of 250-μM lipid chlorohydrins, which is the concentration found in ascitic fluid, induces the expression of TNFα and interleukin-1β in peritoneal macrophages and increases the systemic inflammatory response in pancreatitis. Finally, increased concentrations of oleic acid chlorohydrin have been found in plasma of human patients with pancreatitis.. During acute pancreatitis, adipose tissue release FA-Cl, which exacerbate the systemic inflammatory response.

Topics: Acute Disease; Animals; Biomarkers; Case-Control Studies; Chlorohydrins; Cholagogues and Choleretics; Chromatography, Liquid; Fat Necrosis; Gas Chromatography-Mass Spectrometry; Humans; Inflammation; Linoleic Acid; Macrophage Activation; Male; Mass Spectrometry; Oleic Acid; Pancreatitis; Peroxidase; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Taurocholic Acid

An experimental model of chronic pancreatitis was induced by a retrograde injection of a viscous solution consisting of zein-oleic acid-linoleic acid (0.05 ml/100 g body weight) into the rat pancreatic duct. Histologic and biochemical changes were investigated over a period of 6 months after induction of this model. The treated rats gained weight, but pancreatic weight decreased with time. Histologically, the widening of acinar lumen and cellular vacuolization occurred within 24 h at the parenchyma neighboring the small ducts filled with the injected solution. Degenerative parenchyma, interstitial edema, and inflammatory cell infiltration were pronounced 1 week later. Thereafter, duct-like tubular complex formation progressed, and the exocrine tissue exhibited marked atrophy of the gland with irregular fibrosis and fat replacement over a period of 6 months. Pancreatic contents of protein, amylase, DNA, and RNA markedly decreased, as did pancreatic weight, whereas hydroxyproline content increased. Oral administration of camostat did not affect pancreatic weight and contents of enzyme in this model. Urinary para-aminobenzoic acid (PABA) excretion in the BT-PABA test decreased to 54% at 6 weeks and 22% at 6 months. Although three quarters of pancreatic immunoreactive insulin (IRI) content was lost after 6 months, overt diabetes did not occur. The results suggest that an obstructive mechanism in the small ducts plays an important role in the genesis and development of chronic pancreatitis.

Topics: Amylases; Animals; Blood Glucose; Body Weight; Chronic Disease; Disease Models, Animal; Esters; Gabexate; Guanidines; Linoleic Acid; Male; Oleic Acid; Organ Size; Pancreas; Pancreatic Ducts; Pancreatitis; Protease Inhibitors; Rats; Rats, Wistar; Solutions; Survival Rate; Zein

It was reported that free fatty acids degraded from triglycerides by lipase may play a major role in acute necrotizing or hyperlipidemia-induced pancreatitis. We hypothesized that this injury may be related to the peroxidation of cell membrane phospholipids and tested this hypothesis using isolated pancreatic acini. Pancreatic acini were prepared from male Sprague-Dawley rats by collagenase digestion. Linoleic acid was added (0.1-1.0 mM) to the acinar cell suspension to induce cell injury. Acinar cell damage was measured by lactate dehydrogenase release and by trypan blue exclusion. Phosphatidylcholine hydroperoxide and alpha-tocopherol in the acinar cells were measured. Protective effects of alpha-tocopherol (0.5, 5.0 mM) against this type of cell injury were also evaluated. When isolated acinar cells were treated with linoleic acid, a significant decrease in viability was observed in a time- and dose-dependent manner. In addition, the levels of phosphatidylcholine hydroperoxide after treatment of 0.5 mM of linoleic acid were increased and levels of alpha-tocopherol were decreased significantly. alpha-Tocopherol significantly ameliorated both cellular injury (p < 0.01) and increases in phosphatidylcholine hydroperoxide (p < 0.01). These data suggest that lipid peroxidation of the cellular membrane is an important component of the pancreatic cell injury mediated by free fatty acids.

Topics: Animals; Dose-Response Relationship, Drug; Kinetics; L-Lactate Dehydrogenase; Linoleic Acid; Lipid Peroxidation; Luminescent Measurements; Male; Pancreas; Pancreatitis; Phosphatidylcholines; Rats; Rats, Sprague-Dawley; Vitamin E

The role of oxygen derived free radicals or tissue lipid peroxides in the pathogenesis of chronic pancreatitis has not been established. To evaluate long-term effects of tissue lipid peroxides in the pathogenesis of chronic pancreatitis, we treated Wistar male rats with 2,2'-azo-bis-(2-amidino-propane) dihydrochloride (AAPH) and/or linoleic acid (LA) for 3 or 6 months. Rats were divided into eight groups. A: Saline-treated rats for 3 months as control, B: AAPH 40 mg/kgw intraperitoneally, twice a week for 3 months, C: LA 0.5 ml/kgw intraperitoneally, every other week for 3 months, D: AAPH and LA for 3 months, E: Saline-treated for 6 months, F: AAPH for 6 months, G: LA for 6 months, H: AAPH and LA for 6 months. The results were as follows: Lipid peroxide contents of the pancreas were elevated in groups: C, D, G and H. Histological examination revealed epithelial hyperplasia of large pancreatic ducts, vacuolization of ductal epithelium, intraepithelial neutrophilic infiltration, periductal mononuclear cell infiltration (ductulitis and peri-ductulitis), and sporadically in the lobules, destruction of acinar cells, neutrophilic infiltration and ductular proliferation in the same groups. These findings indicate that tissue damage was more severe in the pancreatic ducts than in the acinar cells, however no damage was seen in the endocrine pancreas. Vitamin E content of the pancreas was decreased in groups: B, C, D, F, G and H. Tissue glutathione peroxidase (GSH-Px) activity was increased in groups: D and H. Tissue catalase activity was increased in groups: D, G and H, but no change of superoxide dismutase (SOD) activity was seen in any of the groups. These results indicate that vitamin E may play the role of the main scavenger in the situation of a smaller dose of lipid peroxides, but when larger doses are administered, GSH-Px may play the main role as the scavenger in this experimental system.

Topics: Amidines; Animals; Chronic Disease; Free Radical Scavengers; Free Radicals; Glutathione Peroxidase; Linoleic Acid; Linoleic Acids; Lipid Peroxides; Male; Pancreas; Pancreatitis; Rats; Rats, Wistar

Multiple i.p. injections of low-dose streptozotocin (40 mg/kg) produce insulitis, beta cell destruction, and diabetes in male CD-1 mice. Recent data also suggest that macrophages figure in the low-dose streptozotocin model. Because other recent studies have shown that essential fatty acid deficiency prevents autoimmune nephritis in mice, decreases the number of resident Ia-positive glomerular macrophages, and decreases the elicitation of macrophages into the glomerulus in inflammation, we examined the effect of essential fatty acid deficiency on the incidence and severity of insulitis and diabetes in CD-1 mice treated with low-dose streptozotocin. Streptozotocin-treated mice on the control diet uniformly developed diabetes (19/19). Essential fatty acid-deficient mice treated with streptozotocin did not develop diabetes (1/13). Mean plasma glucose levels for the control and essential fatty acid-deficient mice were 384.5 +/- 23.6 and 129.1 +/- 15.5 mg/dl, respectively, at the end of 1 month. To discern whether essential fatty acid deficiency prevented the streptozotocin-induced beta cell injury or the inflammatory response to injured beta cells, mice were repleted with daily injections of 99% pure methyl linoleate beginning 3 days after the last streptozotocin injection. These mice also quickly developed severe (3/4) or mild (1/4) diabetes. Histologic examination of the pancreata of control mice or repleted mice showed marked insulitis and beta cell destruction; in contrast, the pancreata of essential fatty acid-deficient mice showed preservation of beta cells and only focal mild peri-insulitis. Essential fatty acid deficiency thus prevents the insulitis and resultant diabetes in low-dose streptozotocin-treated CD-1 mice, suggesting a central role for macrophages and lipid mediators in this autoimmunity model.

Topics: Animals; Diabetes Mellitus, Experimental; Fatty Acids, Essential; Histocompatibility Antigens Class II; Islets of Langerhans; Linoleic Acid; Linoleic Acids; Macrophages; Male; Mice; Pancreatitis

High concentrations of lipid peroxidation (free-radical oxidation) products have been found in bile from patients with recurrent pancreatitis, and the principal component, after hydrolysis, has been identified as an isomerised form of linoleic acid -- typical concentration 25 mmol/l, compared with 4 mmol/l in controls. Chromatographically identical products can be generated by peroxidising linoleic acid using an ultraviolet (UV) source in the presence of albumin, whereas peroxidation by lipoxidase without albumin results in a constellation of products that bear no resemblance to those in biological fluids. These facts, and the suspicion that reflux of abnormal bile may be an initiating mechanism in acute pancreatitis, led us to investigate the effects of linoleic acid peroxidation products in the rat pancreas. Two concentrations of ultraviolet-peroxidised linoleic acid were used (3.6 mmol/l or 25 mmol/l, in a 2.09% solution of bile salts containing albumin 10 g/l) to simulate the human findings and, for comparison, the effects of lipoxidase-peroxidised linoleic acid, 25 mmol/l (in the 2.09% bile salt solution but without albumin), were also studied. 100 microliter of test solution was infused retrogradely into the pancreatic duct using a syringe pump. The results were assessed microscopically at 3-h intervals, and histologically at 12 h: if the animal died before the end of the experiment, the time of death was recorded. Both forms of peroxidised linoleic acid, 25 mmol/l, caused a greater degree of pancreatic injury than that produced by bile salts alone (e.g., macroscopic score at 3 h: ultraviolet, P less than 0.001; lipoxidase, P less than 0.05). Non-peroxidised linoleic acid 25 mmol/l caused less damage than ultraviolet-peroxidised linoleic acid 25 mmol/l, both macroscopically (3 h: P less than 0.01; 12 h: P less than 0.05) and on histology (P less than 0.01). Pancreatic haemorrhage was not a feature.

Topics: Acute Disease; Animals; Bile Acids and Salts; Linoleic Acid; Linoleic Acids; Lipid Peroxides; Male; Oxidoreductases; Pancreas; Pancreatitis; Rats; Rats, Inbred Strains; Ultraviolet Rays