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M1723

Plasma Motilin Responses to Prokinetic Therapy in Feed Intolerant CriticallyIll PatientsNam Q. Nguyen, Robert J. Fraser, Laura Bryant, Carly M. Burgstad, Marianne Chapman,Spencer Clarke, Richard H. Holloway, Arduino Mangoni

Enteral feeding is the preferred nutritional approach for critically ill patients but is limitedby feed intolerance in 50% of patients. Prokinetic therapy with metoclopramide (dopamineantagonist/5-TH4 agonist) and/or low dose (1-3mg/kg) erythromycin (motilin agonist)increases gastric emptying, but rapid loss of efficacy is frequent (Nguyen CCM 2007).Recent data suggest that higher plasma erythromycin concentrations are associated with lesssuccessful prokinetic treatment in these patients (DDW 2009). It has been suggested thatrapid loss of motor effects of erythromycin may reflect high motilin concentrations andsubsequent down regulation of motilin receptors (Lamian Mol Pharmacol 2006). There areno data on the effects of prokinetics on plasma motilin concentrations in these patients.Aim: To assess the effects of metoclopramide and erythromycin treatment on plasma motilinconcentrations in feed intolerant critically ill patients. Methods: Fifty five feed-intolerant(gastric residual volume (GRV) >250ml) mechanically ventilated, critically ill patients (37M,50±2 yrs; APACHE II: 22.9±0.7) received either metoclopramide 10mg QID (n=27) orerythromycin 200mg BD (n=18). Success of enteral feeding (6hr GRV ≤250ml with feedingrate ≥40ml/h) was determined over 7 days. Plasma motilin concentrations were measuredby radioimmunoassay 1 and 7 hr after the first prokinetic dose. Data are mean ± SEM.Comparison by t-tests. Results: On Day 1, plasma motilin concentrations were increased7hrs after the administration of metoclopramide (1 to 7h post-dose 89±15 to 111±19 pg/ml; P=0.02), but not erythromycin. Plasma motilin concentrations in patients treated withmetoclopramide were higher 7h post-dose (111±19 vs. 65±6pg/ml; P=0.02). Patients whodid not respond to either prokinetic therapy within 24h had higher plasmamotilin concentra-tions at 1 hr than those with successful treatment (116±28 vs. 69±9 pg/ml, P=0.05) witha similar trend at 7h (120±30 vs. 76±10 pg/ml, P=0.09). There was a weak negative correlationbetween plasma motilin concentrations 7h post-dose and time to loss of prokinetic effect(P=0.04, r= -0.28). Conclusions: In feed-intolerant critically ill patients, prokinetic treatmentwith metoclopramide, but not erythromycin, is associated with increased plasma motilinconcentrations. The lack of response and shorter time to loss of efficacy are consistent withalteration in motilin receptor sensitivity. The unexpected marked elevation in motilin withmetoclopramide could contribute to rapid tachyphylaxis seen with this agent and suggestits mechanism of action may be more complex than previously appreciated.

M1724

Effect of Different Kind of Dietary Lipid on Glucagon-Like Peptide-2 (GLP-2)Concentration in Intestinal Lymph of RatsShingo Sato, Ryota Hokari, Hideaki Hozumi, Toshihide Ueda, Masaaki Higashiyama,Yoshikiyo Okada, Chie Kurihara, Chikako Watanabe, Mitsuyasu Nakamura, KanjiWakabayashi, Atsushi Kawaguchi, Shigeaki Nagao, Soichiro Miura

Background:GLP-2 is a proglucagon-derived peptides released from intestinal L-cells, andrecently its therapeutic potential by intestinal epithelial proliferation has been in the spotlight. Fatty acids (FAs) have been reported as intestinotropic agents and are known to stimulateintestinal epithelial proliferation. Thus, we hypothesized that FAs influence the secretion ofGLP-2 and proliferative effect of FAs on intestinal epithelium is GLP-2 dependent. However,its very short half-life time in a venular concentration makes it difficult to study changesof GLP-2 concentration by luminal nutrients. We previously reported oral intake of FAsaffect lymph flow which was measured by canulating thin tube into rat intestinal lymph.Recently it is reported that concentration of GLP-1, another proglucagon-derived peptides,is much higher in the intestinal lymph than venules. The aim of this study is to clarifywhether effect of orally administered FAs on the secretion of GLP-2 differs among nutrientsby measuring GLP-2 in an intestinal lymph. Methods : Male Wistar Rats weighing 200-250g were used. A silicon tube was implanted into the duodenum to administer reagentsand 3Fr plastic tube into the thoracic duct to collect lymph. After surgical procedures, theywere placed into a restrainer cage, and saline was infused at 3ml/h into the duodenum tocompensate for lymph loss. A single bolus with 3ml of one of the following five infusateswas administered at 12-h intervals to each rat ; 1) Panacet ; middle-chain triglycerides ; 2)olive oil ; 3) fish oil ; 4) perilla oil; and 5) 33% sucrose solution. At 12hrs after surgerylymph was collected, and then lymph sample was collected at 2hrs after each nutrientinfusion. Concentrations of GLP-2 were determined by ELIZA (Yanaihara, Fujinomiya Japan).Serum concentrations of GLP-2 were also measured. Results : Baseline lymph GLP-2 concen-tration was 3.35 ± 0.36 ng/ml and increased rapidly in response to olive oil (18.49ng/ml),perilla oil (29.18ng/ml), and sucrose solution (21.64ng/ml). Those increase were recoveredafter 12 hours of ingestion. In contrast, Panacet did not increase lymph GLP-2 concentration(1.9ng/ml). Conclusions : We for the first timemeasured concentrations of GLP-2 in intestinallymph . Using this method, the effects on GLP-2 concentration by different kinds of luminalnutrients were successfully determined. Not only perilla oil but also olive oil and sucroseaugment lymph concentration of GLP-2 in rats . The information of difference of nutrientsin increasing GLP-2 secretion will give us a new strategy for nutritional therapy againstinflammatory disease and mucosal injury.

S-406AGA Abstracts

M1725

Food Intake and Interdigestive Gastrointestinal Motility in Ghrelin ReceptorMutant RatsMehmet Bulbul, Reji Babygirija, Jun Zheng, Kirk A. Ludwig, Jozef Lazar, Toku Takahashi

Background: Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor(GHSR). Ghrelin regulates feeding activity and gastric interdigestive motility in rodents. Tofurther investigate the role of endogenous ghrelin in feeding and interdigestive motility,we have developed GHSR-mutant rats, named FHH-Ghsr10m1Mcwi using Fawn-HoodedHypertensive (FHH) parental strain. Methods: N-ethyl-N-nitrosourea (ENU) was used asmutagen. Genomic DNA prepared from tail clip was analyzed using targeting induced locallesions in genomes (TILLING) approach. The non-synonymous mutation in position 343(NM_032075) lead to generation of premature stop codon causing deletion of last 22 aminoacids at C-terminal of protein of ghrelin receptor. After a 24-hr fasting, spontaneous andghrelin-stimulated cumulative food intake were measured 30, 60, 120 and 180 min afterstarting the feeding in wild type (WT) and FHH-Ghsr10m1Mcwi rats. For motility recording,two strain gauge transducers were sutured on the antrum and duodenum. Interdigestivecontractions were recorded in freely moving conscious rats. Results: Body weight was notsignificantly different between WT rats (281.5±13.1g, n=10) and FHH-Ghsr10m1Mcwi rats(281.0±23.9g, n=10). Spontaneous food intake was not significantly different between WT(3.7±0.4 g, n=6) and FHH-Ghsr10m1Mcwi (3.7±0.7 g, n=6) rats. However, ghrelin (40 μg/kg, ip) significantly increased food intake in WT (5.1±0.7 g, n=6), but not in FHH-Ghsr10m1Mcwi rats (3.7±0.4 g, n=6) in the first 30 min of feeding. Gastric and duodenalphase III-like contractions were observed in both of WT and FHH-Ghsr10m1Mcwi rats. InWT rats, ghrelin (12 μg/kg, ip) enhanced the motility index of phase III-like contractionsof the antrum (149.3±1.1 % increase of basal, n=6) and duodenum (117.0±3.5 % increaseof basal, n=6). In contrast, ghrelin (12 μg/kg, ip) failed to stimulate gastroduodenal contrac-tions in FHH-Ghsr10m1Mcwi rats (99.5±4.9 % increase of basal in the antrum and 99.9±1.3% increase of basal in the duodenum, n=6). A GHSR antagonist [(D-lys3)GHRP-6 (0.28mg/kg, ip)] administration abolished the spontaneous phase III-like contractions in WT rats,but not in FHH-Ghsr10m1Mcwi rats. Conclusion: These results suggest that intact GHSRstructure is essential for ghrelin-dependent regulation of interdigestive motility and feedingbehavior. Even in FHH-Ghsr10m1Mcwi rats, spontaneous gastric phase III-like contractionswere still observed, suggesting a compensatory mechanism.

M1726

Role of the GPR39 Receptor, a Member of the Ghrelin Receptor Family, in theRegulation of Glucose Homeostasis in a Mouse Model of Diet-Induced ObesityPieter-Jan Verhulst, Anneleen Lintermans, Sara Janssen, Johan Buyse, Jan F. Tack, IngeDepoortere

The GPR39 receptor is a member of the family that also includes receptors for ghrelin andmotilin. The downregulation of GPR39 mRNA in adipose tissue of obese type 2 diabeticpatients suggests that GPR39 may contribute to the pathogenesis of the disease. We thereforestudied the role of GPR39 in body weight control and glucose homeostasis in a mousemodel of type 2 diabetes. Methods: GPR39 knockout (GPR39-/-) and wild-type (GPR39+/+)mice were fed a high-fat diet (HFD)(60% kcal from fat) or standard diet (SD) during 30weeks. An oral glucose (OGTT; 2g/kg) tolerance test was performed at week 15 and 30.Changes in plasma insulin and ghrelin levels were measured by radioimmunoassay. Respirat-ory quotient (RQ) was determined by indirect calorimetry. Results: Expression of GPR39mRNA in epididymal adipose tissue of fasted GPR39+/+ mice was reduced after 30 weekson a HFD (SD: 5.5±0.5 vs HFD: 3.7±0.5; P<0.05). Body weight, fat percentage and energyintake was increased in the HFD-group but did not differ between both genotypes. A positivecorrelation (r: 0.79, P<0.001) was observed between GPR39 expression in adipose tissueand fasted blood glucose levels of GPR39+/+ mice on a HFD but not on a SD. Within theHFD-group, blood glucose levels were lower (P<0.01) in GPR39-/- than in GPR39+/+ micebetween week 22 and 30. Evidence of altered insulin sensitivity was obtained in an OGTTwhere either a reduction (week 15) or no change (week 30) in blood glucose levels wasobserved in GPR39-/- mice compared with GPR39+/+mice despite significant reductions inplasma insulin levels in GPR39-/- mice. RQ values were increased in GPR39-/- mice on aHFD but not on a SD, indicating that GPR39-/- mice preferentially used carbohydrates asenergy source. This is an agreement with the lower blood glucose levels observed in GPR39-/-

mice and the possible alterations in insulin sensitivity. Plasma octanoylated ghrelin levels weremarkedly higher (P<0.05) in GPR39-/- (42.8±7.6 pg/ml) than in GPR39+/+ mice (11.8±1.2 pg/ml) after 30 weeks on a HFD but not in mice on a SD. Ghrelin levels were inverselyproportional to plasma insulin levels (GPR39-/-: 12.1±1.8; GPR39+/+: 30.7±6.7 pg/ml) butwere not significantly correlated. Gastric emptying (T1/2) was delayed by the HFD but didnot differ between both genotypes (GPR39+/+: 126±6 min; GPR39-/-: 125±7 min) suggestingthat it does not contribute to differences in blood glucose levels between both genotypes.Conclusion: Our results suggest that GPR39 plays a role in the regulation of glucose homeost-asis but not in the control of body weight during conditions of increased demand for insulinsecretion such as diet-induced obesity.

M1727

Maltase-Glucoamylase: Mucosal Regulator of Prandial Starch Glucogenesis andComplementary Hepatic Gluconeogenesis of MiceMaricela Diaz-Sotomayor, Roberto Quezada-Calvillo, Avery Stephen, Chacko Shaji, LikeYan, Bruce R. Hamaker, Buford L. Nichols

Aim: It was hypothesized that the slower rate of starch digestion by residual sucrase-isomaltase (Si) maltase failed to fully regulate gluconeogenesis. In the present study the rateof gluconeogenesis was measured directly (J Appl Physiol 104: 944-951, 2008) and comparedwith exogenous glucose derived from starch digestion by Mgam (Maltase-glucoamylase) nulland WT (Wild Type) mice. Methods: The Mgam null and WT mice have been previouslypublished (J. Nutr.137: 1725-1733, 2007). The null mice with only Si have a 58% reductionin jejunal glucogenic activity. The experimental mice were on a low 13C-diet (MPE% (mol