CompletedNot Applicable

Protein Digestion and Amino Acid Absorption in the Aging Gastrointestinal Tract

Netherlands24 participantsStarted 2024-08-20

Plain-language summary

Rationale: Worldwide, the aging population is increasing. Aging is associated with loss of independence and increased risk of co-morbidity. Sufficient protein intake is imperative to maintain skeletal muscle mass and overall health, and thereby stimulates active aging. It has been suggested that age-dependent changes in gastrointestinal (GI) tract physiology affect the amount of protein digested and absorbed, as well as the intestinal microbiota. However, it is not clear to what extent actual protein digestion and absorption are altered in older individuals. So far, no human data on the expression and activity of brush border enzymes and protein-related transporters in small intestinal epithelial cells are available. Understanding the age-dependent digestion and absorption kinetics of protein is important for creating specific diets in older individuals to improve protein intake and thereby stimulate healthy aging. Objective: To assess the effects of aging on protein digestion and amino acid absorption in healthy humans in vivo. Study design: Cross-sectional Study population: 12 healthy, non-obese (BMI 18.5-30kg/m2) young adults (age: 18-35 y inclusive) and 12 community dwelling older adults (age: ≥67 y). Intervention: Subjects will undergo a standardized heavy water dosing protocol for 2 days (1 "loading day", 1 "maintenance day"). Blood and saliva sampling will be conducted throughout the heavy water dosing protocol to determine body water and amino acid enrichment levels. On the experimental test day, a gastroscopy with collection of duodenal mucosa tissue samples will be performed to allow assessment of the expression and activity of brush border enzymes and protein-related transporters, and to determine fractional duodenal mucosal protein synthesis rate. Fecal samples will be collected at baseline and after the gastroscopy. Main study parameters/endpoints: The primary study parameter is the mRNA expression of brush border enzymes and small peptide and amino acid transporters in duodenal mucosal cells. Secondary study parameters include protein expression of brush border enzymes and small peptide and amino acid transporters in duodenal mucosal cells, fecal microbial fermentation metabolites and duodenal mucosal protein synthesis rate.

Who can participate

Age range

18 Years

Sex

ALL

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Inclusion Criteria: * Aged 18-35 years or 67+ years * Body mass index (BMI) between 18.5 and 30 kg/m2 * Regular stool frequency ranging from 1-3 times/day Exclusion Criteria: * History of cardiovascular, respiratory, gastrointestinal, urogenital, neurological, psychiatric, dermatologic, musculoskeletal, metabolic, endocrine, haematological, immunologic disorders, allergy, major surgery and/or laboratory assessments which might limit participation in or completion of the study protocol, interfere with the execution of the experiment, or potential influence the study outcomes (to be decided by the principal investigator and responsible physician) * Major abdominal surgery interfering with gastrointestinal function (upon judgement of the principal investigator and responsible physician) * Use of medication which limit participation in or completion of the study protocol, interferes with the execution of the experiment, or potential influences the study outcomes (to be decided by the principal investigator and responsible physician) * Use of supplementation (i.e. protein, vitamin, pre- and probiotic supplementation) within 14 days prior to testing * Administration of investigational drugs or participation in any scientific intervention study prior or during the study, which may interfere with this study (upon judgement of the principal investigator and responsible physician) Specific diet (e.g. vegetarian, vegan, gluten free, no diary) within the study period * Planning to los…

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1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
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Questions for the trial coordinator

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1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
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6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Gene expression of brush border enzymes and protein-related transporters in duodenal mucosal cells

Timeframe: day 3 of study period

Trial details

NCT IDNCT06553794

SponsorMaastricht University Medical Center

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2025-06-13

View on ClinicalTrials.gov More Protein Malabsorption trials