| 1. |
- Hernell, Olle, et al.
(författare)
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Does the bile salt stimulated lipase of human milk have a role in the use of the milk long-chain polyunsaturated fatty acids?
- 1993
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Ingår i: Journal of Pediatric Gastroenterology and Nutrition - Jpgn. - 1536-4801 .- 0277-2116. ; 16:4, s. 426-431
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Tidskriftsartikel (refereegranskat)abstract
- Long-chain polyunsaturated (LCP) fatty acids derived from linoleic (18:2 n-6) and alpha-linolenic (18:3 n-3) acids are considered essential nutrients in preterm infants. The efficiency by which such fatty acids are released as absorbable products from triacylglycerol was explored in vitro using rat chylomicron triacylglycerol as substrate. When incubated with purified human pancreatic colipase-dependent lipase and colipase, arachidonic acid (20:4 n-6) was released less efficiently than linoleic acid from such triacylglycerol. This difference was not seen when purified human milk bile salt-stimulated lipase (BSSL) was incubated with the triacylglycerol substrate, and it was almost abolished when colipase-dependent lipase (with colipase) and BSSL acted simultaneously, as they do in breast-fed infants. There was no difference in arachidonic acid and eicosapentaenoic acid (20:5 n-3) release rates with either colipase-dependent lipase or BSSL, albeit the release was more rapid with the milk enzyme than with colipase-dependent lipase. Again, the most efficient release as absorbable free fatty acids was achieved when the two lipases operated together. The relative resistance to hydrolysis of arachidonic acid and eicosapentaenoic acid by colipase-dependent lipase was best explained by the localization of the first double bond to the delta-5 position of the respective fatty acid. The results obtained suggest that BSSL is of importance for the efficient use of human milk LCP fatty acids.
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| 2. |
- Andersson, Eva-Lotta, et al.
(författare)
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Bile salt-stimulated lipase and pancreatic lipase-related protein 2 : key enzymes for lipid digestion in the newborn examined using the Caco-2 cell line
- 2011
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Ingår i: Journal of Lipid Research. - : American Society for Biochemistry and Molecular Biology. - 0022-2275 .- 1539-7262. ; 52:11, s. 1949-1956
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Tidskriftsartikel (refereegranskat)abstract
- In rodents, bile salt-stimulated lipase (BSSL) and pancreatic lipase-related protein 2 (PLRP2) are the dominant lipases expressed in the exocrine pancreas in early life, when milk is the main food. The aim of the present study was to evaluate if BSSL and PLRP2 are also key enzymes in neonatal intestinal fat digestion. Using Caco-2 cells as a model for the small intestinal epithelium, purified human enzymes were incubated in the apical chamber with substrates and bile salt concentrations resembling the milieu of the small intestine of newborn infants. BSSL and PLRP2 hydrolyzed triglycerides (TG) to free fatty acids (FA) and glycerol. The cells took up the FA, which were reesterfied to TG. Together, BSSL and PLRP2 have a synergistic effect, increasing cellular uptake 4-fold compared to the sum of each lipase alone. A synergistic effect was also observed with retinyl ester as a substrate. PLRP2 hydrolyzed cholesteryl ester but not as efficiently as BSSL, and the two had an additive rather than synergistic effect. We conclude the key enzymes in intestinal fat digestion are different in newborns than later in life. Further studies are needed to fully understand this difference and its implication for designing optimal neonatal nutrition.
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| 3. |
- Bernbäck, S, et al.
(författare)
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Bovine pregastric lipase : a model for the human enzyme with respect to properties relevant to its site of action.
- 1987
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 922:2, s. 206-13
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Tidskriftsartikel (refereegranskat)abstract
- Preduodenal lipolysis is considered to promote efficient lipid digestion in the neonatal period. The lipase(s) responsible may be of pregastric or gastric origin depending upon the species. We have previously reported on purification and molecular characterization of a pregastric lipase from calf. Antibodies to this bovine enzyme crossreact with a protein of similar size in human gastric contents and also inhibit its lipolytic activity. Since the bovine and human enzymes also have similar kinetic properties, the view is favoured that the bovine enzyme can be used as a model for physiological studies relevant to human neonates. In contrast to the lipases operating in the small intestine pregastric lipase has the unique property of initiating the hydrolysis of human milk fat globule triacylglycerol. In order to do this no cofactor is required. Pregastric lipase was stable at low pH and had an acid-pH optimum. Furthermore, it was extremely resistant to pepsin. In contrast, pancreatic proteinases, i.e. trypsin and chymotrypsin, inactivated the enzyme. The rate of inactivation was increased in the presence of bile salts which by themselves could inhibit enzyme activity. Thus, pregastric lipase is ideally suited for activity in the stomach but will not, under healthy conditions, contribute to lipid digestion in the duodenum.
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| 4. |
- Bernbäck, S, et al.
(författare)
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Fatty acids generated by gastric lipase promote human milk triacylglycerol digestion by pancreatic colipase-dependent lipase.
- 1989
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 1001:3, s. 286-93
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Tidskriftsartikel (refereegranskat)abstract
- The concerted action of purified bovine gastric lipase and human pancreatic colipase-dependent lipase and colipase, or crude human pancreatic juice, in the digestion of human milk triacylglycerols was explored in vitro. Gastric lipase hydrolyzed milk triacylglycerol with an initially high rate but became severely inhibited already at low concentration of released fatty acid. In contrast, colipase-dependent lipase could not, by itself, hydrolyze milk triacylglycerol. However, a short preincubation of milk with gastric lipase, resulting in a limited lipolysis, made the milk fat triacylglycerol available for an immediate and rapid hydrolysis by pancreatic juice, and also for purified colipase-dependent lipase, provided colipase and bile salts were present. The same effect was obtained when incubation with gastric lipase was replaced by addition of long-chain fatty acid. Long-chain fatty acid increased the binding of colipase-dependent lipase to the milk fat globule. Binding was efficient only in the presence of both fatty acid and colipase. We conclude that a limited gastric lipolysis of human milk triacylglycerol, resulting in a release of a low concentration of long-chain fatty acids, is of major importance for the subsequent hydrolysis by colipase-dependent lipase in the duodenum.
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| 5. |
- Bernbäck, S, et al.
(författare)
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The complete digestion of human milk triacylglycerol in vitro requires gastric lipase, pancreatic colipase-dependent lipase, and bile salt-stimulated lipase.
- 1990
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 85:4, s. 1221-6
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Tidskriftsartikel (refereegranskat)abstract
- Gastric lipase, pancreatic colipase-dependent lipase, and bile salt-stimulated lipase all have potential roles in digestion of human milk triacylglycerol. To reveal the function of each lipase, an in vitro study was carried out with purified lipases and cofactors, and with human milk as substrate. Conditions were chosen to resemble those of the physiologic environment in the gastrointestinal tract of breast-fed infants. Gastric lipase was unique in its ability to initiate hydrolysis of milk triacylglycerol. Activated bile salt-stimulated lipase could not on its own hydrolyze native milk fat globule triacylglycerol, whereas a limited hydrolysis by gastric lipase triggered hydrolysis by bile salt-stimulated lipase. Gastric lipase and colipase-dependent lipase, in combination, hydrolyzed about two thirds of total ester bonds, with monoacylglycerol and fatty acids being the end products. Addition of bile salt-stimulated lipase resulted in hydrolysis also of monoacylglycerol. When acting together with colipase-dependent lipase, bile salt-stimulated lipase contributed also to digestion of tri- and diacylglycerol. We conclude that digestion of human milk triacylglycerol depends on three lipases with unique, only partly overlapping, functions. Their concerted action results in complete digestion with free glycerol and fatty acids as final products.
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| 6. |
- Blind, Per Jonas, et al.
(författare)
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Carboxylic ester hydrolase : a serum marker of acute pancreatitis
- 1987
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Ingår i: Pancreas. - 0885-3177 .- 1536-4828. ; 2:5, s. 597-603
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Tidskriftsartikel (refereegranskat)abstract
- By use of an enzyme-linked immunosorbent assay we established serum reference values of carboxylic ester hydrolase, a pancreatic secretory lipolytic enzyme, and explored to see if a raised serum level is indicative of acute pancreatitis. Postoperative elevation of carboxylic ester hydrolase was observed in seven out of ten patients who underwent pancreatic surgery. Serum levels of carboxylic ester hydrolase and amylase were determined in 129 patients admitted due to abdominal emergency conditions. Amylase was elevated in 27 patients, and in 20 of these raised carboxylic ester hydrolase levels affirmed the diagnosis acute pancreatitis. In five out of the seven patients with elevated amylase alone no etiologic factor of acute pancreatitis was found. Another 11 patients had raised carboxylic ester hydrolase levels without concomitant elevation of amylase. In all these patients, a likely cause of pancreatic inflammation was identifiable. Hence, a raised carboxylic ester hydrolase level, even in presence of normal amylase, could be indicative of acute pancreatic inflammation.
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| 7. |
- Blind, Per-Jonas, et al.
(författare)
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Carboxylic ester hydrolase. A sensitive serum marker and indicator of severity of acute pancreatitis.
- 1991
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Ingår i: International journal of Pancreatology. - 0169-4197. ; 8:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- When using clinical criteria, both falsely positive and falsely negative diagnoses of acute pancreatitis (AP) are often made. Based on a clinical study, elevated serum levels of the pancreatic lipolytic enzyme carboxylic ester hydrolase (CEH) was recently suggested to be a highly specific marker of acute pancreatitis. To determine the sensitivity of the test for AP, a study on patients with the diagnosis set objectively was necessary. In the present study, AP was diagnosed by contrast-enhanced computed tomography in 64 patients, and histopathological examination of tissue removed at laparotomy in 18 of them. By these criteria, 42 patients suffered from acute interstitial pancreatitis (AIP), and 22 patients from necrotizing pancreatitis (NP). Based on the CEH concentrations in the first serum sample obtained in each patient, the sensitivity of CEH for pancreatitis was 98%. From the second day after admission, CEH levels in patients with NP were significantly higher than in patients with AIP. Furthermore, in patients with NP, CEH values remained at a raised level for the following 10 d, whereas a significant decrease of CEH values was noted in patients with AIP. In contrast, total serum amylase activities were higher in patients suffering of AIP than in patients suffering of NP during the observation period. We conclude, that the sensitivity of the CEH test is very high for AP. CEH concentrations remaining at a high level are suggestive of NP, whereas diminishing CEH levels are suggestive of AIP.
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| 8. |
- Bläckberg, Lars, et al.
(författare)
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Bile salt-stimulated lipase in human milk. Evidence that bile salt induces lipid binding and activation via binding to different sites.
- 1993
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 323:3, s. 207-210
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Tidskriftsartikel (refereegranskat)abstract
- Human milk bile salt-stimulated lipase ensures efficient triacylglycerol utilization in breast-fed newborns. For activity against long-chain triacylglycerol, primary bile salts are a prerequisite. Bile salts also protect the enzyme from inactivation by intestinal proteases. We have studied the effect of different bile salts on activation, protease protection, lipid binding, and enzyme inactivation, caused by an arginine modifying agent. Based on the results we propose a model involving two bile salt binding sites; one activation-site specific for primary bile salt, and another, less specific, lipid binding promoting site at which also secondary bile salt binds. Binding to this latter site induces binding of enzyme to emulsified substrates but binding promoting site at which also secondary bile salt binds. Binding to this latter site induces binding of enzyme to emulsified substrates but without subsequent lipolysis.
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| 9. |
- Bläckberg, Lars, et al.
(författare)
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Further characterization of the bile salt-stimulated lipase in human milk
- 1983
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 157:2, s. 337-341
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Tidskriftsartikel (refereegranskat)abstract
- Bile salt-stimulated lipase is a milk enzyme unique to the higher primates. Its molecular and kinetic characteristics differ greatly from other lipolytic enzymes; e.g., pancreatic lipase and lipoprotein lipase. It has a much higher app. Mr, 310000 on gel filtration and 100000 after denaturation. It requires primary bile salts for optimal activity and bile salts also protect the enzyme from proteolytic and heat inactivation. It may, due to its low substrate specificity, contribute to the utilization of a variety of milk lipids. Since it lacks positional specificity, digestion of milk triglycerides should be complete, which may explain why fat absorption is more efficient in breast-fed than in formula-fed infants.
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| 10. |
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