Pancreatic Triglyceride Research Articles

Fatty acid derivatised analogues of glucose-dependent insulinotropic polypeptide with improved antihyperglycaemic and insulinotropic properties

C-terminal acylation of Lys 37 with myristic (MYR; tetradecanoic acid), palmitic (PAL; hexadecanoic acid) and stearic (octadecanoic acid) fatty acids with or without N-terminal acetylation was employed to develop long-acting analogues of the glucoregulatory hormone, glucose-dependent insulinotropic polypeptide (GIP). All GIP analogues exhibited resistance to dipeptidylpeptidase-IV (DPP-IV) and significantly improved in vitro cAMP production and insulin secretion. Administration of GIP analogues to ob/ob mice significantly lowered plasma glucose—GIP(Lys 37MYR), N-AcGIP(Lys 37MYR) and GIP(Lys 37PAL) increased plasma insulin concentrations. GIP(Lys 37MYR) and N-AcGIP(Lys 37MYR) elicited protracted glucose-lowering effects when administered 24 h prior to an intraperitoneal glucose load. Daily administration of GIP(Lys 37MYR) and N-AcGIP(Lys 37MYR) to ob/ob mice for 24 days decreased glucose and significantly improved plasma insulin, glucose tolerance and beta-cell glucose responsiveness. Insulin sensitivity, pancreatic insulin content and triglyceride levels were not changed. These data demonstrate that C-terminal acylation particularly with myristic acid provides a class of stable, longer-acting forms of GIP for further evaluation in diabetes therapy.

Trp-107 and Trp-253 Account for the Increased Steady State Fluorescence That Accompanies the Conformational Change in Human Pancreatic Triglyceride Lipase Induced by Tetrahydrolipstatin and Bile Salt

The conformation of a surface loop, the lid, controls activity of pancreatic triglyceride lipase (PTL) by moving from a position that sterically hinders substrate access to the active site into a new conformation that opens and configures the active site. Movement of the lid is accompanied by a large change in steady state tryptophan fluorescence. Although a change in the microenvironment of Trp-253, a lid residue, could account for the increased fluorescence, the mechanism and tryptophan residues have not been identified. To identify the tryptophan residues responsible for the increased fluorescence and to gain insight into the mechanism of lid opening and the structure of PTL in aqueous solution, we examined the effects of mutating individual tryptophan residues to tyrosine, alanine, or phenylalanine on lipase activity and steady state fluorescence. Substitution of tryptophans 86, 107, 253, and 403 reduced activity against tributyrin with the largest effects caused by substituting Trp-86 and Trp-107. Trp-107 and Trp-253 fluorescence accounts for the increased fluorescence emissions of PTL that is stimulated by tetrahydrolipstatin and sodium taurodeoxycholate. The largest contribution is from Trp-107. Contrary to the prediction from the crystal structure of PTL, Trp-107 is likely exposed to solvent. Both tetrahydrolipstatin and sodium taurodeoxycholate are required to produce the increased fluorescence in PTL. Alone, neither is sufficient. Colipase does not significantly influence the conformational changes leading to increased emission fluorescence. Thus, Trp-107 and Trp-253 contribute to the change in steady state fluorescence that is triggered by mixed micelles of inhibitor and bile salt. Furthermore, the results suggest that the conformation of PTL in solution differs significantly from the conformation in crystals.

Effects of Ethanol and Its Metabolites on Human Pancreatic Stellate Cells

Pancreatic stellate cells (PSCs) play a pivotal role in pancreatic inflammation and fibrosis. In the pancreas, in addition to oxidative metabolism, ethanol can be metabolized by esterification with fatty acids to form fatty acid ethyl esters such as palmitic acid ethyl ester (PAEE). We here examined the effects of ethanol (at 20 or 50 mM), acetaldehyde (at 200 microM), or PAEE (at 100 microM), on PSCs functions. PSCs did not express mRNAs for pancreatic triglyceride lipase and carboxyl ester lipase. Ethanol and acetaldehyde, but not PAEE, induced production of procollagen type I C-peptide. Ethanol, but not acetaldehyde or PAEE, induced interleukin-8 production. PAEE activated activator protein-1, but not nuclear factor kappaB. In addition, PAEE activated extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase. Specific activation of signal transduction pathways and cell functions by ethanol and its metabolites may play a role in alcohol-induced pancreatic injury.

Dose-related Effect of Propofol on Pancreatic Enzymes and Triglyceride Levels in Patients Undergoing Non-abdominal Surgery

Various case reports have indicated a possible relationship between propofol and pancreatitis. However, it is not clear whether this relationship (if any) is dose-related or idiosyncratic. Therefore, a prospective study was conducted to evaluate the effect of different doses of propofol on postoperative pancreatic enzymes and serum triglyceride levels. One hundred and fifty patients, aged 18 to 60 years, belonging to ASA physical status I and II, undergoing non-abdominal surgery were divided into three groups. Anaesthesia was induced with propofol 2 to 2.5 mg/kg in all groups. It was maintained with isoflurane in group I, propofol infusion < 5 mg/kg/h in group II and propofol infusion > or = 5 mg/kg/h in group III. All three groups also received nitrous oxide in oxygen for maintenance of anaesthesia. Serum amylase, lipase and triglyceride were estimated before propofol administration and at 24 and 72 hours postoperatively. The mean values of serum amylase, lipase and triglyceride remained within the normal range in the three groups. These values did not differ significantly in between the groups even despite the significantly different doses of propofol in the three groups (P < 0.001). None of the patients in the three groups developed any feature suggestive of acute pancreatitis in the postoperative period. These findings indicate that propofol administration at recommended doses does not produce dose-related increases in pancreatic enzyme and triglyceride levels in ASA physical status I and II patients.

Pancreatic lipase-related protein (PY–PLRP) highly expressed in the vitellogenic ovary of the scallop, Patinopecten yessoensis

A cDNA (1206 bp) encoding a pancreatic lipase-related protein (PY–PLRP) was obtained from the ovary of the scallop, Patinopecten yessoensis, using a differentially expressed gene system. The open reading frame specified a protein containing 353 amino acids (~ 38 kDa). The N-terminal catalytic domain, which contained the catalytic triad of serine, aspartate, and histidine residues, 10 cysteine residues involved in disulfide bridges, and the conserved lid domain, indicated that the protein would be catalytically active. However, PY–PLRP lacked the C-terminal colipase-binding domain present in mammalian PLRPs. Sequence analysis of the catalytic domains of PY–PLRP with members of the pancreatic triglyceride lipase (PTL) family suggested that PY–PLRP was related to mammalian PLRP1, PLRP2, and PTL. End-point reverse transcriptase-polymerase chain reaction (RT-PCR) after 25 cycles showed that PY–PLRP was expressed at a high level in the ovary and at low levels in testis and mantle; expression was not detected in gill, digestive gland, and adductor muscle. Quantitative PCR of RNA from ovaries at different stages of development showed that PY–PLRP was expressed at a significantly higher level in the late growth stage than in the ripe and spent stages. These data suggest that PY–PLRP plays a role in lipid metabolism associated with oocyte maturation and vitellogenesis that occurs during ovarian growth.

Carboxyl Ester Lipase from Either Mother’s Milk or the Pancreas Is Required for Efficient Dietary Triglyceride Digestion in Suckling Mice ,

Because dietary fats provide an important source of energy in the newborn, the efficient digestion of dietary fats is critical to their well-being. Despite the importance of dietary fat digestion, newborns have a deficiency of pancreatic triglyceride lipase, the predominant digestive lipase in adults. The efficient dietary fat digestion in newborns suggests that other lipases must compensate for the lack of pancreatic triglyceride lipase. In this study, we test the hypothesis that breast milk, pancreatic carboxyl ester lipase (CEL), or both contribute to dietary fat digestion in the newborn. To test this hypothesis, we determined the amount and composition of fecal fat in wild-type and CEL-deficient newborns nursed by either wild-type or CEL-deficient dams. We tested all genetic permutations of the nursing pairs. An interaction between the genotype of the dam and of the pup determined the amount of fecal fat (P < 0.001). Fecal fat was highest in CEL-deficient pups nursed by CEL-deficient dams. Furthermore, only the feces from the CEL-deficient pups nursed by CEL-deficient dams contained undigested lipids. Even with increased fecal fats, the CEL-deficient pups had normal weight gain. Our results demonstrate that CEL contributes significantly to dietary triglyceride digestion whether it originates from mother’s milk or pancreatic secretions. However, only the absence of both mother’s milk and pancreatic CEL produces fat maldigestion. The absence of a single CEL source makes no difference in the efficiency of dietary fat absorption.

C-terminal mini-PEGylation of glucose-dependent insulinotropic polypeptide exhibits metabolic stability and improved glucose homeostasis in dietary-induced diabetes

Glucose-dependent insulinotropic polypeptide has been proposed as a potential therapeutic for type 2 diabetes, however, efforts to bring forward this drug have been hindered due to its short circulating half-life. We have adopted a novel strategy to increase potency and prolong GIP action through C-terminal mini-PEGylation (GIP[mPEG]). In contrast to GIP, GIP[mPEG] was resistant to dipeptidylpeptidase-IV (DPP-IV) up to and including 24 h. Both GIP[mPEG] and GIP concentration-dependently stimulated cAMP production (EC 50 6.6 and 0.7 nM, respectively) and insulin secretion ( p < 0.01 to p < 0.001) in pancreatic BRIN-BD11 cells. Acute injection of GIP[mPEG] together with glucose to high fat fed mice significantly lowered plasma glucose ( p < 0.05) and increased plasma insulin responses ( p < 0.05). Furthermore, GIP[mPEG] markedly lowered plasma glucose when administered 4–24 h prior to a glucose load ( p < 0.05). Daily administration of GIP[mPEG] for 20 days in high fat mice did not alter body weight, food intake or non-fasting plasma insulin, however, non-fasting plasma glucose concentrations were significantly lowered ( p < 0.05). Moreover, glucose tolerance was significantly improved ( p < 0.05) together with glucose-mediated plasma insulin responses ( p < 0.05). Insulin sensitivity, pancreatic insulin content, triglyceride and adiponectin levels were not changed. In summary, these data demonstrate that C-terminal mini-PEGylation of GIP is a useful strategy to prolong metabolic stability and improve biological action thus representing a novel therapeutic option for type 2 diabetes.

Bile Salt–Stimulated Lipase and Pancreatic Lipase-Related Protein 2 Are the Dominating Lipases in Neonatal Fat Digestion in Mice and Rats

During infancy, the basic conditions for digestion of dietary fat differ from later in life. The bile salt-stimulated lipase (BSSL) is an enzyme expressed in the exocrine pancreas and in some species (including human) also in the lactating mammary gland and secreted with the milk. The aim of this study was to compare the ontogeny of four pancreatic lipases [BSSL, pancreatic triglyceride lipase (PL), pancreatic lipase-related protein 2 (PLRP2), and phospholipase A2 (PLA2)] in one species that supplies BSSL with milk (the mouse) and one that does not (the rat). We followed expression of the four pancreatic lipases from postnatal d 1 until after weaning in both species. We found that BSSL and PLRP2, two lipases with broad substrate specificity, dominated. It was not until weaning that significant expression of PL and PLA2 were induced. Thus, BSSL and PLRP2 seem to be responsible for fat digestion as long as milk is the main food. Moreover, the early temporal pattern of BSSL expression differed between species. We speculate that the milk-borne BSSL is able to compensate for a slower ontogeny of pancreatic BSSL expression in the mouse.

A polymorphism in the gene encoding procolipase produces a colipase, Arg92Cys, with decreased function against long-chain triglycerides

Type 2 diabetes mellitus is a multifactorial and polygenic disorder with increasing prevalence. Recently, a polymorphism in the gene encoding procolipase, a cysteine for arginine substitution at position 92, was associated with type 2 diabetes in two human populations. Because procolipase plays a critical role in dietary fat metabolism, polymorphisms that affect the function of procolipase could influence the development of type 2 diabetes. We hypothesized that the Arg92Cys polymorphism has functional consequences. To test our hypothesis, we expressed recombinant cysteine 92 (Cys92) procolipase in a yeast expression system and compared the function and stability of purified Cys92 with that of the more common arginine 92 (Arg92) procolipase. Cys92 fully restored the activity of bile-salt inhibited lipase with short- and medium-chain triglycerides but only had 50% of Arg92 function with long-chain triglycerides. After storage at 4 degrees C, Cys92 lost the ability to restore pancreatic triglyceride lipase activity with medium- and long-chain triglycerides. The loss of function correlated with the inability of Cys92 to anchor lipase on an emulsion surface and oxidation of the cysteine. No detectable degradation or intramolecular disulfide formation occurred in Cys92 after storage. Our findings demonstrate that the Arg92Cys polymorphism decreases the function of Cys92 colipase. This change may contribute to the development of type 2 diabetes.

Carboxyl Ester Lipase Deficiency Exacerbates Dietary Lipid Absorption Abnormalities and Resistance to Diet-induced Obesity in Pancreatic Triglyceride Lipase Knockout Mice

This study evaluated the contributions of carboxyl ester lipase (CEL) and pancreatic triglyceride lipase (PTL) in lipid nutrient absorption. Results showed PTL deficiency has minimal effect on triacylglycerol (TAG) absorption under low fat dietary conditions. Interestingly, PTL(-)(/)(-) mice displayed significantly reduced TAG absorption compared with wild type mice under high fat/high cholesterol dietary conditions (80.1 +/- 3.7 versus 91.5 +/- 0.7%, p < 0.05). Net TAG absorption was reduced further to 61.1 +/- 3.8% in mice lacking both PTL and CEL. Cholesterol absorption was 41% lower in PTL(-/-) mice compared with control mice (p < 0.05), but this difference was not exaggerated in PTL(-/-), CEL(-/-) mice. Retinyl palmitate absorption was reduced by 45 and 60% in PTL(-/-) mice (p < 0.05) and PTL(-/-), CEL(-/-) mice (p < 0.01), respectively. After 15 weeks of feeding, the high fat/high cholesterol diet, wild type, and CEL(-/-) mice gained approximately 24 g of body weight. However, body weight gain was 6.2 and 8.6 g less (p < 0.01) in PTL(-/-) and PTL(-/-), CEL(-/-) mice, respectively, despite their consumption of comparable amounts of the high fat/high cholesterol diet. The decrease body weight gain in PTL(-/-) and PTL(-/-), CEL(-/-) mice was attributed to their absorption of fewer calories from the high fat/high cholesterol diet, thereby resulting in less fat mass accumulation than that observed in wild type and CEL(-/-) mice. Thus, this study documents that PTL and CEL serve complementary functions, working together to mediate the absorption of a major portion of dietary fat and fat-soluble vitamin esters. The reduced lipid absorption efficiency due to PTL and CEL inactivation also resulted in protection against diet-induced obesity.

Oligomeric Procyanidins in Apple Polyphenol Are Main Active Components for Inhibition of Pancreatic Lipase and Tri-glyceride Absorption

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionOligomeric Procyanidins in Apple Polyphenol Are Main Active Components for Inhibition of Pancreatic Lipase and Tri-glyceride AbsorptionHiroshi Sugiyama, Yoko Akazome, Toshihiko Shoji, , Masaaki Yasue, Tomomasa Kanda, and Yasuyuki OhtakeCite this: J. Agric. Food Chem. 2007, 55, 14, 5906Publication Date (Web):June 14, 2007Publication History Published online14 June 2007Published inissue 1 July 2007https://doi.org/10.1021/jf078004bCopyright © 2007 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views494Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (8 KB) Get e-Alerts Get e-Alerts

Oligomeric Procyanidins in Apple Polyphenol Are Main Active Components for Inhibition of Pancreatic Lipase and Triglyceride Absorption

Inhibitory effects of apple polyphenol extract (AP) and procyanidin contained in AP on in vitro pancreatic lipase activity and in vivo triglyceride absorption in mice and humans were examined. AP and procyanidin considerably inhibited in vitro pancreatic lipase activity. However, polyphenols, except for procyanidin, in AP (i.e., catechins, chalcones, and phenol carboxylic acids) showed weak inhibitory activities on pancreatic lipase. Procyanidins separated by normal-phase chromatography according to the degree of polymerization were also examined. Inhibitory effects of procyanidins increased according to the degree of polymerization from dimer to pentamer. On the other hand, pentamer or greater procyanidins showed maximal inhibitory effects on pancreatic lipase. These results suggested that with respect to in vitro pancreatic lipase inhibition, the degree of polymerization was an important factor and oligomeric procyanidin mainly contributed. Next, we performed a triglyceride tolerance test in mice and humans. Simultaneous ingestion of AP and triglyceride significantly inhibited an increase of plasma triglyceride levels in both models. These results suggested that the oligomeric procyanidins contained in AP inhibited triglyceride absorption by inhibiting pancreatic lipase activity in mice and humans.

Biochemical and structural comparative study between bird and mammal pancreatic colipases

Three colipases were purified from pancreas of two birds (ostrich and turkey) and one mammal (dromedary). After acidic and/or heat treatment and precipitation by sulfate ammonium and then ethanol, cofactors were purified by Sephadex G-50 gel filtration followed by ion-exchange chromatography first on Mono S and then on Mono Q. One molecular form was obtained from each species with a molecular mass of approximately 10 kDa. Cofactors were not glycosylated. The N-terminal sequences of the three purified cofactors showed high sequence homology. A 90 amino acid sequence of the ostrich cofactor was established based on peptide sequences from four different digests of the denaturated protein using trypsin, chymotrypsin, thermolysin, or staphylococcal protease. This sequence exhibited a high degree of homology with chicken and mammal cofactors. Bile salt-inhibited pancreatic lipases from five species were activated to variable extents by colipases from bird and mammal origins. The bird pancreatic lipase-colipase system appears to be functionally similar to homologous lipolytic systems from higher mammals. Our comparative study showed that mammal colipase presents a lower activation level toward bird lipases than the bird counterpart. Three-dimensional modeling of ostrich colipase suggested a structural explanation of this fact.

Effect of Short-term Propofol Administration on Pancreatic Enzymes and Triglyceride Levels in Children

Effect of Short-term Propofol Administration on Pancreatic Enzymes and Triglyceride Levels in Children

Alternate expression of BSSL and other pancreatic lipases during infancy

Background Bile salt-stimulated lipase (BSSL), pancreatic triglyceride lipase (PTL), pancreatic lipase-related protein 2 (PLRP-2), phospholipase A2 and colipase are all expressed in the exocrine pancreas and involved in digestion of dietary fat in the small intestine. BSSL is also expressed in the mammary gland during lactation and is a constituent of the milk in some species, including human. The contribution of BSSL with the milk compensates the low intraluminal levels of PTL and bile salts in infants that otherwise may lead to fat malabsorption. In fact, such fat malabsorption is almost exclusively seen in formula-fed, but not in breast-fed infants. Aim To compare the ontogeny of the four pancreatic lipases and colipase in one species that secretes BSSL in milk (mouse) and one that does not (rat). Methods Quantitative real-time PCR and Western blots were performed to follow lipase expression in pancreas from birth until adulthood in both species. Results BSSL was expressed already at day 1 post-partum. In mice, the level of BSSL mRNA increased gradually from day 1 to reach a peak value around day 7, where after it declined. In contrast, the rat pancreatic BSSL appeared to be constitutively expressed already from day 1 until adulthood. Previous studies showing that PTL and PLA-2 expression is low until the suckling/weanling transition, whereas PLRP-2 and colipase is expressed from day 1 were confirmed in both species. Conclusion BSSL together with PLRP-2 are the dominating lipases involved in fat digestion as long as pups are suckled. Further, in mice lower expression of BSSL the first days seems to be compensated for by BSSL in milk.

Val-407 and Ile-408 in the β5′-Loop of Pancreatic Lipase Mediate Lipase-Colipase Interactions in the Presence of Bile Salt Micelles

In a previous study, we demonstrated that the beta5'-loop in the C-terminal domain of human pancreatic triglyceride lipase (hPTL) makes a major contribution in the function of hPTL (Chahinian et al. (2002) Biochemistry 41, 13725-13735). In the present study, we characterized the contribution of three residues in the beta5'-loop, Val-407, Ile-408, and Leu-412, to the function of hPTL. By substituting charged residues, aspartate or lysine, in these positions, we altered the hydrophilic to lipophilic ratio of the beta5'-loop. Each of the mutants was expressed, purified, and characterized for activity and binding with both monolayers and emulsions and for binding to colipase. Experiments with monolayers and with emulsions suggested that the interaction of hPTL with a phospholipid monolayer differs from the interaction of the hPTL-colipase complex with a dicaprin monolayer or a triglyceride emulsion (i.e. neutral lipids). Val-407, Ile-408, and Leu-412 make major contributions to interactions with monolayers, whereas only Val-407 and Ile-408 appear essential for activity on triglyceride emulsions in the presence of bile salt micelles. In solutions of taurodeoxycholate at micellar concentrations, a major effect of the beta5'-loop mutations is to change the interaction between hPTL and colipase. These observations support a major contribution of residues in the beta5'-loop in the function of hPTL and suggest that a third partner, bile salt micelles or the lipid interface or both, influence the binding of colipase and hPTL through interactions with the beta5'-loop.

Putative association between a new polymorphism in exon 3 (Arg109Cys) of the pancreatic colipase gene and type 2 diabetes mellitus in two independent Caucasian study populations

The protein encoded by the pancreatic colipase (CLPS) gene is an essential cofactor needed by pancreatic triglyceride lipase (PNLIP) for efficient dietary lipid hydrolysis. Since the inhibition of lipase activity was shown to reduce the incidence of type 2 diabetes mellitus, we tested the hypothesis that genetic variations in the CLPS and PNLIP genes are associated with type 2 diabetes; 47 unrelated subjects were screened for polymorphisms of the CLPS and PNLIP genes. A nested-case control study of 192 incident type 2 diabetes subjects and 384 sex- and age-matched controls taken from the European Prospective Investigation into Cancer and Nutrition Potsdam Cohort (EPIC) was employed for association studies. The Metabolic Intervention Cohort Kiel (MICK) consisting of 716 males was used for verification. A novel putative functional polymorphism (Arg109Cys) was identified in the CLPS gene. The frequencies of the Arg/Cys genotype were 2.6% in EPIC and 2.2% in MICK study subjects. No homozygotes for the Cys/Cys genotype were found in either study population. Logistic regression analysis showed a statistically significant association of the Arg/Cys genotype with an increased risk of type 2 diabetes. The odds ratios estimated by the model were 3.75 (95%CI = 1.13-12.49, p = 0.03) in EPIC and 4.86 (95%CI = 1.13-20.95, p = 0.03) in MICK. No comparable associations were found with other traits of the insulin-resistance syndrome (e. g.; body mass index, waist to hip ratio). In conclusion, we obtained evidence in two German Caucasian study populations that the variant of the rare CLPS Arg109Cys polymorphism might contribute to increased susceptibility of type 2 diabetes.

MECHANISMS OF DIGESTION AND ABSORPTION OF DIETARY VITAMIN A

Mechanisms involved in the digestion and absorption of dietary vitamin A require the participation of several proteins. Dietary retinyl esters are hydrolyzed in the intestine by the pancreatic enzyme, pancreatic triglyceride lipase, and intestinal brush border enzyme, phospholipase B. Unesterified retinol taken up by the enterocyte is complexed with cellular retinol-binding protein type 2 and the complex serves as a substrate for reesterification of the retinol by the enzyme lecithin:retinol acyltransferase (LRAT). The retinyl esters are then incorporated into chylomicrons, intestinal lipoproteins containing other dietary lipids, such as triglycerides, phospholipids, and free and esterified cholesterol, and apolipoprotein B. Chylomicrons containing newly absorbed retinyl esters are then secreted into the lymph. Although under normal dietary conditions much of the dietary vitamin A is absorbed via the chylomicron/lymphatic route, it is also clear that under some circumstances there is substantial absorption of unesterified retinol via the portal route. Evidence supports the idea that the cellular uptake and efflux of unesterified retinol by enterocytes is mediated by lipid transporters, but the exact number, identity, and role of these proteins is not known and is an active area of research.

Effects of short‐term propofol administration on pancreatic enzymes and triglyceride levels in children

This prospective, clinical trial evaluated the effects of short-term propofol administration on triglyceride levels and serum pancreatic enzymes in children undergoing sedation for magnetic resonance imaging. Laboratory parameters of 40 children, mean age (SD; range) 67 (66; 4-178) months undergoing short-term sedation were assessed before and 4 h after having received propofol. Mean (SD) propofol loading dose was 2.2 (1.1) mg.kg(-1) followed by continuous propofol infusion of 6.9 (0.9) mg.kg(-1).h(-1). Serum lipase levels (p = 0.035) and serum triglyceride levels (p = 0.003) were raised significantly after propofol administration but remained within normal limits. No significant changes in serum pancreatic-amylase levels were seen (p = 0.127). In two (5%) children, pancreatic enzymes and in four (10%) children triglyceride levels were raised above normal limits; however, no child showed clinical symptoms of pancreatitis. We conclude that even short-term propofol administration with standard doses of propofol may have a significant effect on serum triglyceride and pancreatic enzyme levels in children.

Molecular mechanisms of cholesterol absorption and transport in the intestine

Many enzymes and transport proteins participate in cholesterol absorption. This review summarizes recent results on several proteins that are important for each step of the cholesterol absorption pathway, including the important roles of: (i) pancreatic triglyceride lipase (PTL), carboxyl ester lipase (CEL), and ileal bile acid transporter in determining the rate of cholesterol absorption; (ii) ATP binding cassette (ABC) transporters and the Niemann-Pick C-1 like-1 (NPC1L1) protein as intestinal membrane gatekeepers for cholesterol efflux and influx; and (iii) intracellular membrane vesicles and transport proteins in lipid trafficking through intracellular compartments prior to lipoprotein assembly and secretion to plasma circulation.