GLP-2 Induces Intestinal Adaptation in Jejunal Remnant Osama Bawazir FRCSI, FRCS(Ed), FRCS (glas), FRCSC. G.R. Martin, L.E. Wallace and D.L. Sigalet. Gastrointestinal Research Group, University of Calgary, Calgary, AB

INTRODUCTION  Resection > 50 % of small bowel → Short Bowel Syndrome (SBS).  SBS → severe diarrhea, dehydration, nutrient malabsorption, electrolyte imbalance, micronutrient deficiencies, weight loss, long- term dependence on parenteral nutrition.  In the pediatric population, total parenteral nutrition (TPN) → sepsis, secondary liver failure,  morbidity.

 NEC in preterm baby.  Midgut volvulus with Malrotation  Small bowel atresia

 Distal small bowel resection is the most common clinical scenario In SBS  We try to create module similar to the common clinical presentation of SBS

Adaptation: Mechanisms Adaptation as process of ↑ in absorptive capacity of the bowel & ↑ in the surface area.  Increase in villous height/crypt depth   CCPR  ?  crypt apoptosis   nutrient absorption  ↑ permeability Control

 We have previously shown that GLP-2 stimulates intestinal adaptation in the terminal ileum.  GLP-2 is an intestinal trophic hormone  ↑ crypt cell proliferation → increase in absorptive surface area.  GLP-2 release following resection is correlated with the adaptive up-regulation of nutrient transport.  We hypothesized that GLP-2 would stimulate intestinal adaptation in jejunal remnant following massive intestinal resection.

GLP-2 GLP-2R Nutrient {FAT} L-cells Dipeptidyl peptidase IV GLP >> GLP Trophic  less trophic 33 amino acid peptide 7 minute ½ life PACAP / glucagon super family GLP-2 Background ↑ satiety ↓motility

TPN Bowel resection Line insertion 5 mL vial mL vial 2 = 10 Multi-XII vitamins 1.8Magnisium sulfate 36Calcium gluconate 10KCl (2meq/mL) 16NaCl (23.4% solution) % dextrose solution 28010% Travasol solution Volume in 500 mL bag (mLs) Ingredient + Intralipid (20 %) isocaloric / isonitroge nous 75.5 kcal, 11.4 g CHO, 2.8 g protein, 2.0 g fat /Day TPN + GLP2 GLP-2 Infusion 10 µg/kg/hr METHODS

 Body weight changes were monitored over the 8 day study  Serum GLP-2 levels: ELIZA N-terminus of native GLP-2(1-33)  Intestinal Permeability: 20-hr urinary recovery of gavaged carbohydrate probes (3-0 methyl- glucose, lactulose, and mannitol)

 Day 8 →pulsed with BRDU (lables active dividing cell), euthanized. Tissues processed for morphology,crypt cell proliferation rates  Apoptosis was assessed by activated caspase-3 expression using immuno- histochemical staining  Nutritional transport capacity was assessed by mucosal expression of Na+-dependent glucose co-transporter-1 (SGLT-1) and Glut-5 (Western blot)Endpoints

Intestinal Permeability

groupBody weight (% change) Small bowel weight (g) Small bowel % BWT Small bowel Length (cm) Small bowel Width (cm) TPN6.52±5.11.3±0.30.5± ± ± GLP-2 * 8.33± 2.9 * 2.7±0.4 * 1.0± ± ± Gross Morphology * P<0.05. Data expressed as mean ± SEM.

Morphology *P<0.05. Data expressed as mean ± SEM. Representative photos visualized at 10x. TPNTPN + GLP-2 groupVillus ht (um) Crypt depth (um) Villus density C/V ratiovilli surface area um² TPN534 ± 58157± ± ± /-11 TPN+GLP2 * 808 ± 27 * 207 ± ± ± 0.03 * /-15

GroupMicro Villus height Micro Villus width Micro Villius density Micro Villus surface area TPN1.9 ± ± ± ± 0.2 TPN+GLP2*2.3 ± ± 0.1*17.4 ± 0.6*4.7 ±-0.4 Ultra-structural Morphology TPNTPN + GLP-2 * P<0.05. Data expressed as mean ± SEM.

Crypt Cell Proliferation { Brdu +ve cell / Crypt} Crypt BRDU immunoreactivity

Apoptosis {Activated Caspase-3 +ve cell / Crypt}

Transporter Protein Expression SGLT1 = Active transport GLUT-5 = Passive transport

Serum GLP-2 Levels Basal serum GLP-2 levels. Blood sampled on day 8 in the a.m. Data expressed as mean ± SEM. *P<0.02 versus TPN group

SUMMARY  GLP-2 ↓ intestinal permeability  ↑ crypt cell proliferation, small bowel weight, and morphological measures of adaptation in jejunum  GLP-2 treatment did not change the expression of the active nutrient transporter SGLT-1.(?! May be SGLT-1 at maximum up- regulation)  There were significant changes in apoptosis (↑) as assessed by activated caspase-3 expression.

 These findings differ from the effects of GLP-2 on residual ileum noted in our previous studies, showing that different segment of bowel had different reaction and variable adaptation to the GLP2.  This study supports the use of GLP-2 in TPN maintained patients following intestinal resection.  Further studies to determine the optimal timing, dosing, and latency period are required.

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