Search

Apelin is an enteric peptide that exerts several digestive functions such as stimulation of cell proliferation and cholecystokinin (CCK) secretion. We investigated using murine enteroendocrine cell line (STC-1) and rats if apelin-13 stimulates both CCK and glucagon-like peptide 1 (GLP-1) secretions. We demonstrated that, in vitro and in vivo, apelin-13 increases the release of these two hormones in a dose-dependent manner. Present data suggest that apelin may modulate digestive functions, food intake behavior and glucose homoeostasis via apelin-induced release of enteric CCK but also through a new incretin-releasing activity on enteric GLP-1., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Bioactive peptides obtained from marine species and marine by-products are showing these days a great interest in nutraceutical and pharmaceutical applications due to their wide range of biological activities. This mini-review focuses on the potential of marine peptides to be used as appetite suppressive molecules in the prevention and/or in the treatment of obesity syndrome. An important and promising aspect in the fight against obesity is the study of anorexigenic gut hormones, like cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1), that are synthetized by enteroendocrine cells in the presence of nutrients in the gastrointestinal tract. Recent works which have focused on the interaction between marine peptides and CCK and GLP-1 are here reviewed.

Food-derived hemorphins were studied for their interactions with intestinal cells in relation to food intake regulations. LLVV-H4, LVV-H4, VV-H4, VV-H7 and H7 were identified in the 2 h-intestinal hydrolysate of haemoglobin simulated gastrointestinal digestion and synthesised. These food-derived hemorphins showed secretagogue properties of the anorexigenic hormones cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) when in contact with murine STC-1 cells. They did not show significant modulatory effect on the corresponding prohormones mRNA levels. However, they downregulated the enzyme PC1 that processes proglucagon into GLP-1 specifically in the intestine. Moreover, VV-H4, VV-H7 & H7 were potent inhibitors of the GLP-1 inactivating dipeptidyl-peptidase IV (DPP-IV) and transiently upregulated its mRNA in human Caco-2 cells. These results suggest that food-derived hemorphins display dual luminal effects that participate at different levels in food intake and glycaemia regulation and add to the known roles of the special class of food-derived opioid peptides, the hemorphins. [ABSTRACT FROM AUTHOR]

Dietary proteins have been reported to induce a strong feeling of satiety that has been partially explained by gut hormone level increase. Up to date, various protein hydrolysates have demonstrated in vitro and in vivo their potential to stimulate gut hormone secretion related to food intake decrease and their mechanisms of action have just started to be resolved. In this context, this study aimed at identifying new peptide sequences involved in gut hormone secretion released by protein in vitro gastrointestinal digestion. Targeted gut hormones were Cholecystokinin (CCK) and Glucagon-Like Peptide 1 (GLP-1). The activity of DPP-IV was also considered as it strongly modulates GLP-1 action. In a previous study, simulated digestion of dietary protein has generated hydrolysates with enhancing effect on CCK and GLP-1 secretion in STC-1 cells as well as DPP-IV inhibitory properties. Successive purification steps were performed to isolate peptide fractions involved in these bioactivities whose sequence was determined by LC-MS-MS. Three peptide sequences ANVST, TKAVEH and KAAVT were pointed out for their stimulating effects on GLP-1 secretion. The sequence VAAA was isolated for its DPP-IV inhibitory properties. Two peptide groups were strongly involved in CCK release sharing a certain occurrence of aromatic amino acid residues. [ABSTRACT FROM AUTHOR]

Abstract: To find appetite suppressive molecules derived from fish protein hydrolysates, both in vitro and in vivo experiments were performed in order to demonstrate that hydrolysates produced from blue whiting muscle (BWMH) possess satiating properties. Here we demonstrated for the first time that a protein hydrolysate obtained from marine source was able to enhance cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) secretion in STC-1 cell line. To demonstrate that these in vitro activities also exist in vivo, we investigated the effect of BWMH preload administration in rats and its repercussion on food intake and metabolic plasma marker levels. Results showed that BWMH reduced the short term food intake which was correlated to an increase in the CCK and GLP-1 plasma levels. Moreover it was demonstrated that the chronic administration of BWMH led to a decrease in the body weight gain. [Copyright &y& Elsevier]

Abstract: Fish protein hydrolysates (FPH) are of significant interest, due to their potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. Here, we investigated the action of FPH from blue whiting (Micromesistius poutassou) and brown shrimp (Penaeus aztecus) on cholecystokinin release from intestinal endocrine cells (STC-1). We demonstrated for the first time that FPH were able to highly stimulate CCK-releasing activity from STC-1 cells and that this stimulation was mainly due to peptide molecules. The partial purification of CCK-stimulating peptides showed that their apparent molecular weight ranged between 1000 and 1500Da for fish and crustacean FPH, respectively. Finally, in an aim to industrially produce hydrolysates enriched in CCK-stimulating molecules, we tested the effects of membrane processes (ultrafiltration and nanofiltration) on active peptide enrichments. [Copyright &y& Elsevier]