Nutrient Sensing in the Duodenum

Study Overview
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Brief Summary
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Preliminary studies in humans suggest that the presence of lipids in the gut can modify glucose absorption. The overall hypothesis of this proposal is that long chain fatty acid sensing in the duodenum has a significant role in modifying nutrient (glucose and amino acid) absorption from the GI tract through a gut-brain-gut axis.

Detailed Description
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The investigator will conduct a study in 20 lean (BMI = 19-27 kg/m2) subjects involving intravenous (IV) and intraduodenal (ID) infusions of glucose tracers or amino acid tracers and measurement of tracer rate of appearance in the plasma. An ID infusion of LCFA will allow the investigators to determine if LCFA can alter nutrient absorption and glucose and amino acid metabolism. Benzocaine will be added to the ID infusion of LCFA to inhibit nerve terminals in the duodenum thereby preventing gut-brain communication. Plasma levels of glucose and amino acid tracers, glucose oxidation (13CO2 breath test), gut hormones (CCK, GIP, PYY, GLP-1, ghrelin), and bioactive lipids (N-acyl phosphatidylethanolamines, NAPEs) will be measured during all infusion periods.

Official Title
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Duodenal Lipid Sensing and Nutrient Absorption

Conditions
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The Effect of LCFA on Nutrient Absorption

Intervention / Treatment
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* Drug: Benzocaine Infusion into Duodenum


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI = 19-27 kg/m2 30-55 years of age Exclusion Criteria: Contraindication for nasal tube placement (e.g. deviated septum, prior upper gastrointestinal bleed, or history of easy bleeding) Prior gastric or intestinal surgery or pancreas resection Females with a positive pregnancy test Known history of intestinal diseases including (but not limited to) inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease), celiac sprue, Barrett's esophagus Type 1 or type 2 diabetes Gastroenteritis (diarrhea and/or vomiting) or constipation within the past week

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Benzocaine Infusion into Duodenum<br>The investigator will conduct a study in 20 lean (BMI = 19-27 kg/m2) subjects involving intravenous (IV) and intraduodenal (ID) infusions of glucose tracers or amino acid traces and measurement of tracer rate of appearance in the plasma. An ID infusion of LCFA will allow the investigators to determine if LCFA can alter nutrient absorption and glucose and amino acid metabolism. Benzocaine will be added to the ID infusion of LCFA to inhibit nerve terminals in the duodenum thereby preventing gut-brain communication. Plasma levels of glucose and amino acid tracers, glucose oxidation (13CO2 breath test), gut hormones (CCK, GIP, PYY, GLP-1, ghrelin), and bioactive lipids (N-acyl phosphatidylethanolamines, NAPEs) will be measured during all infusion periods. | Drug: Benzocaine Infusion into Duodenum<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Nutrient Absorption | Stable isotope tracers (glucose or amino acid) will be administered intravenously (IV) and intraduodenally (ID) and tracer rate of appearance in the plasma will be measured. | 6 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Substrate Oxidation | Oxidation of intraduodenally administered glucose or amino acid will be determined by the amount of 13C recovered from expired air. | 6 hours | 
| Gut Hormone Levels | Plasma levels of gut hormones will be measured by standard RIA or ELISA assays | 6 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Nutrient absorption, Duodenal feeding tube, Gut-brain-gut axis