NCT05816551 - Aging and Gastrointestinal Barrier Function | Crick

Overview

The purpose of this study is to assess the gastrointestinal responses of the elderly and younger populations during hyperthermia.

Heat waves are lethal and cause a disproportionate number of deaths in the elderly relative to any other age group. Although gastrointestinal barrier dysfunction is a primary cause of heat related illness, little is known about the effects of aging on gastrointestinal barrier function during hyperthermia. The central hypothesis of this work is that the elderly exhibit greater gastrointestinal barrier dysfunction during hyperthermia. Participants will complete a control trial where gastrointestinal permeability (without heating) will be assessed in young and older adults. In the experimental trial, controlled hyperthermia will be achieved using a water perfused, tube lined suit. Core body temperature will be raised to a maximum of 2 degrees Celsius above the baseline value, or an absolute temperature of 39.5 degrees Celsius. Core temperature will not be collected during the control trial. Comprehensive assessments of gastrointestinal barrier function and systemic inflammation will be assessed in young and older adults. The expected outcome of this work will re-shape our understanding of the consequences of aging on gastrointestinal barrier function during heat waves.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

22

Conditions

Aging Hyperthermia

Interventions

Hyperthermia TrialOTHER

Individuals will be exposed to a controlled hyperthermia trial during "Visit 2" of the protocol.

Control TrialOTHER

Individuals will be exposed to a control trial (no hyperthermia) during "Visit 1" of the protocol.

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy male and female individuals * 18-35 years or 65+ years of age * Free of any underlying moderate to serious medical conditions Exclusion Criteria: * Known heart disease * Any chronic medical conditions requiring regular medical therapy including cancer, diabetes, uncontrolled hypertension, inflammatory bowel disease, and uncontrolled hypercholestrolmia etc; * Abnormality detected on routine screening suggestive of provocable ischemia or previously undetected cardiac disease or resting left bundle branch block on screening electrocardiogram. * Current smokers, as well as individuals who regularly smoked within the past 3 years * Subject with a body mass index ≥35 kg/m2 * Pregnant * Use of immunosuppressant drugs within last 4 weeks prior to screening * Use of antibiotics or antimicrobial medication in last month * Any previous abdominal surgery * Use of steroids in last 6 weeks * Regular use of probiotics in last month * Use of laxatives or anti-diarrhetic in last month

Locations (1)

Texas Health Presbyterian Hospital Dallas

Dallas, Texas, United States

Outcomes

Primary Outcomes

Log Lactulose/Rhamnose Following Control Trial

In vivo gastrointestinal permeability measured by quantities of orally ingested multi-sugar drink excreted in urine. The urinary recovery of each ingested sugar (lactulose, sucrose and rhamnose) was determined by multiplying the measured concentration of each sugar by the total volume of urine collected and dividing by the dose administered. Since lactulose is degraded in the colon, we used the ratio urine lactulose to rhamnose (L/R) to determine small intestinal barrier permeability.

Time frame: "Visit 1": 3-5 hours after ingestion of multiple sugar drink.

Log Lactulose/Rhamnose Following Hyperthermia Trial

In vivo gastrointestinal permeability measured by quantities of orally ingested multi-sugar drink excreted in urine. The urinary recovery of each ingested sugar (lactulose, sucrose and rhamnose) was determined by multiplying the measured concentration of each sugar by the total volume of urine collected and dividing by the dose administered. Since lactulose is degraded in the colon, we used the ratio urine lactulose to rhamnose (L/R) to determine small intestinal barrier permeability.

Time frame: "Visit 2": 3-5 hours after ingestion of multiple sugar drink.

Log Sucrose Following Control Trial

The urinary recovery of sucrose was determined by multiplying the measured concentration of sucrose by the total volume of urine collected and dividing by the dose administered. Sucrose is broken down rapidly in the duodenum, thus we used the urinary excretion of sucrose to assess and gastroduodenal permeability.