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- Emek, Sinan Cem, et al.
(författare)
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Pigments protect the light harvesting proteins of chloroplast thylakoid membranes against digestion by gastrointestinal proteases
- 2011
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 25:6, s. 1618-1626
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Tidskriftsartikel (refereegranskat)abstract
- Chloroplast thylakoid membranes inhibit pancreatic lipase/colipase activity in vitro and, when included in food, induce satiety signals. As thylakoid membranes themselves are nutrients, containing lipids and proteins, it is of interest to study the digestion of thylakoids by enzymes of the gastrointestinal tract. Thylakoid membranes were treated with pepsin, trypsin, gastric and pancreatic juice at 37 degrees C and the resulting enzymatic breakdown was analyzed by gel electrophoresis, electron microscopy and mass spectroscopy. In all cases, several of the proteins were degraded within half an hour, while the main parts of the pigment-protein complexes were resistant for hours. Oil emulsified thylakoids were more resistant towards the enzymatic breakdown. Electron microscopy demonstrated that, after treatments, the thylakoids still remained in a membrane vesicular form. The capacity of thylakoid membranes to inhibit the lipase/colipase activity was partly reduced in all cases. About 50% of the inhibition capacity remained after treatment with pancreatic juice when the thylakoids were present in an oil emulsion. Delipidated thylakoids and plasma membranes, which lack the photosynthetic pigments, were degraded rapidly by pancreatic juice. Conclusion: The pigments, closely bound to the trans-membrane helices of thylakoid membrane proteins protect these from digestion by pepsin, trypsin, gastric and pancreatic juice. This supports the notion that a substantial inhibition of lipase/colipase takes place during the first 2 h in the intestine resulting in a retardation and prolongation of lipolysis in vivo. (C) 2010 Elsevier Ltd. All rights reserved.
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| 4. |
- Köhnke, Rickard, et al.
(författare)
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Feeding appetite suppressing thylakoids to pigs alters pancreatic lipase/colipase secretion
- 2010
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413. ; 134:1-3, s. 68-71
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Konferensbidrag (refereegranskat)abstract
- The mechanism for a new appetite suppressor named thylakoids (membrane proteins derived from spinach leaves) was examined in vivo in pigs. Thylakoids inhibit the lipase/colipase hydrolysis of triacylglycerols (TG) in vitro and suppress food intake, decrease body weight gain and raise the circulating satiety hormone cholecystokinin (CCK) in rats but its mechanism in vivo remains unclear. We hypothesized that a thylakoid-enriched diet prolongs intestinal digestion of food and therefore promote satiety signaling. Five pigs were surgically prepared with a fistula in the duodenum for collection of digesta and with two catheters, one in v. jugularis and one in v. porta, for blood collection. After 1 week of recovery and an overnight fast the pigs were fed a high-fat diet with and without supplementation with thylakoids. Duodenal content and blood samples were taken before and 15, 30, 60, 120, 240 and 360 min after feeding. Pancreatic lipase and colipase enzymes were measured in duodenal digesta. Blood samples were analyzed for the satiety hormone CCK as well as insulin and glucose. We found that pancreatic lipase/colipase level increased and stayed elevated for a longer time in the duodenum in the pigs receiving thylakoids compared to the control. CCK levels were unchanged. Insulin levels were significantly reduced by the thylakoid treatment without any change in blood glucose. In conclusion, thylakoids increased lipase/colipase secretion. The mechanism for this secretion appears not to be related to CCK and may be an effect of vagal activation. Thylakoids gave reduced insulin levels without any change in glucose levels. (C) 2010 Published by Elsevier B.V.
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| 5. |
- Montelius, Caroline, et al.
(författare)
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Chloroplast thylakoids reduce glucose uptake and decrease intestinal macromolecular permeability.
- 2011
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Ingår i: British Journal of Nutrition. - 1475-2662. ; 106:6, s. 836-844
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoid membranes, derived from chloroplasts, have previously been shown to retard fat digestion and lower blood glucose levels after oral intake. The purpose of the present study was to investigate the effect of thylakoid membranes on the passage of methyl-glucose, dextran and ovalbumin over rat intestine in vitro using Ussing chambers. The results show that thylakoids retard the passage of each of the test molecules in a dose-dependent way. The thylakoids appear to be attached on the mucosal surface and a mechanism is suggested that the thylakoids delay the passage of the test molecules by sterical hindrance. The present results indicate that thylakoid membranes may be useful both to control intestinal absorption of glucose and to enhance the barrier function of the intestine.
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| 6. |
- Montelius, Caroline, et al.
(författare)
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Dietary thylakoids suppress blood glucose and modulate appetite-regulating hormones in pigs exposed to oral glucose tolerance test.
- 2014
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Ingår i: Clinical Nutrition. - : Elsevier BV. - 1532-1983 .- 0261-5614. ; 33:6, s. 1122-1126
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Tidskriftsartikel (refereegranskat)abstract
- Dietary chloroplast thylakoids have previously been found to reduce food intake and body weight in animal models, and to change metabolic profiles in humans in mixed-food meal studies. The aim of this study was to investigate the modulatory effects of thylakoids on glucose metabolism and appetite-regulating hormones during an oral glucose tolerance test in pigs fed a high fat diet.
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| 7. |
- Montelius, Caroline, et al.
(författare)
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Feeding spinach thylakoids to rats modulates the gut microbiota, decreases food intake and affects the insulin response
- 2013
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Ingår i: Journal of Nutritional Science. - : Cambridge University Press (CUP). - 2048-6790. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoid membranes derived from green leaf chloroplasts affect appetite-regulating hormones, suppress food intake, reduce blood lipids and lead to a decreased body weight in animals and human subjects. Thylakoids also decrease the intestinal in vitro uptake of methyl-glucose in the rat. The aim of this study was to investigate the effect of dietary thylakoids on the gut microbiota composition, mainly the taxa of lactobacilli and bifidobacteria, in rats fed either a thylakoid-enriched diet or a control diet for 10 d. At the same time, a glucose-tolerance test in the same rats was also performed. Food intake was significantly decreased in the thylakoid-fed rats compared with the control-fed rats over the 10-d study. An oral glucose tolerance test after 10 d of thylakoid- or control-food intake resulted in significantly reduced plasma insulin levels in the thylakoid-fed rats compared with the control-fed rats, while no difference was observed for blood glucose levels. Analysis of gut bacteria showed a significant increase of lactobacilli on the ileal mucosa, specifically Lactobacillus reuteri, in the rats fed the thylakoid diet compared with rats fed the control diet, while faecal lactobacilli decreased. No difference in bifidobacteria between the thylakoid and control groups was found. Analyses with terminal restriction fragment length polymorphism and principal component analysis of faeces demonstrated different microbial populations in the thylakoid- and control-fed animals. These findings indicate that thylakoids modulate the gut microbial composition, which might be important for the regulation of body weight and energy metabolism.
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| 8. |
- Sileikiene, Vaida, et al.
(författare)
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Effect of ileal infusion of short-chain fatty acids on pancreatic prandial secretion and gastrointestinal hormones in pigs
- 2008
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Ingår i: Pancreas. - 0885-3177. ; 37:2, s. 196-202
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Nutrients passing the ileum induce mechanisms regulating pancreatic secretion, but the effect of short-chain fatty acids (SCFAs) present in the ileum because of either intestinal fermentation or due to the cecoileal reflux is still unclear. This study investigated the effect of ileal SCFAs on pancreatic secretion and plasma levels of peptide YY, cholecystokinin, motilin, and neurotensin. Methods: The pigs were fitted with pancreatic duct, ileal, and jugular vein catheters, and a duodenal T-shaped cannula. Saline, 85.0 or 170.0 mM acetate, 5.0 or 10.0 mM butyrate, 7.5 or 15.0 mM propionate were infused into the ileum during feeding. Results: The ileal infusions of SCFAs did not affect the pancreatic juice outflow and the lipase output. The protein output was lower when 10.0 mM butyrate or 170.0 mM acetate were infused. The trypsin output decreased for most of the SCFA infusions. The alpha-amylase output decreased for the infusion of 10.0 mM butyrate and tended to decrease for 170.0 mM acetate. The infusions did not change gut hormone level. Conclusions: Ileal SCFAs might induce an inhibition of pancreatic enzyme secretion under prandial conditions. Ileal SCFAs do not inhibit pancreatic secretion by a hormonal pathway involving the release of peptide YY, motilin, neurotensin, or cholecystokinin.
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| 9. |
- Stenblom, Eva Lena, et al.
(författare)
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Dietary thylakoids reduce visceral fat mass and increase expression of genes involved in intestinal fatty acid oxidation in high-fat fed rats
- 2016
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Ingår i: American Journal of Physiology - Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 311:3, s. 618-627
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Tidskriftsartikel (refereegranskat)abstract
- Thylakoids reduce body weight gain and body fat accumulation in rodents. This study investigated whether an enhanced oxidation of dietary fat-derived fatty acids in the intestine contributes to the thylakoid effects. Male Sprague-Dawley rats were fed a high-fat diet with (n = 8) or without thylakoids (n = 8) for 2 wk. Body weight, food intake, and body fat were measured, and intestinal mucosa was collected and analyzed. Quantitative realtime PCR was used to measure gene expression levels of key enzymes involved in fatty acid transport, fatty acid oxidation, and ketogenesis. Another set of thylakoid-treated (n = 10) and control rats (n = 10) went through indirect calorimetry. In the first experiment, thylakoidtreated rats (n = 8) accumulated 25% less visceral fat than controls. Furthermore, fatty acid translocase (Fat/Cd36), carnitine palmitoyltransferase 1a (Cpt1a), and mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) genes were upregulated in the jejunum of the thylakoid-treated group. In the second experiment, thylakoid-treated rats (n = 10) gained 17.5% less weight compared with controls and their respiratory quotient was lower, 0.86 compared with 0.91. Thylakoid-intake resulted in decreased food intake and did not cause steatorrhea. These results suggest that thylakoids stimulated intestinal fatty acid oxidation and ketogenesis, resulting in an increased ability of the intestine to handle dietary fat. The increased fatty acid oxidation and the resulting reduction in food intake may contribute to the reduced fat accumulation in thylakoid-treated animals.
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