Adipose Tissue Blood Flow in Aging Humans

Study Overview
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Brief Summary
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The goal of this basic science clinical trial is to understand whether adipose tissue blood flow changes between younger and older healthy adults. The main question[s] it aims to answer are: Is basal and nutrient responsive adipose tissue blood flow (ATBF) different between younger and older adults What molecular and systemic signatures related to adipose tissue blood flow are altered between these two groups. Participants will undergo measurements of adipose tissue blood flow using the xenon washout technique, undergo 2 abdominal subcutaneous adipose tissue biopsies, and drink a sugary drink.

Detailed Description
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On Visit 1, volunteers will provide written informed consent (and urine pregnancy test for women of childbearing age), complete a Dual x-ray absorptiometry scan, baseline labs (comprehensive metabolic panel) and a cardiopulmonary exercise test. Participants will arrive fasted at 08:00, and urine pregnancy test for women of childbearing age administered and an intravenous catheter will be placed. Following 30min of supine rest, baseline venous blood samples will be collected. ATBF will be assessed on participants' left abdomen first by measurement of blood flow using 133Xenon washout method. Immediately thereafter, an abdominal adipose tissue biopsy of the left side will be performed but ≥6 cm distant from location of 133Xenon injections. Subjects will them consume 75 gm glucose; because ATBF peaks 30-60 minutes following ingestion of glucose, ATBF measures will start 30 minutes after ingestion on the contralateral side followed immediately by plasma measures and another adipose tissue biopsy. During ATBF measurements, brachial blood pressure will be assessed in two-minute intervals.

Official Title
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Adipose Tissue Blood Flow in Aging Humans

Conditions
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Healthy, Aging

Intervention / Treatment
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* Other: 75 gm oral glucose load


Participation Criteria
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Eligibility Criteria
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Inclusion criteria Within the ages of 18-35 years or 65-80 years at time of study visit BMI between 20-25.0 kg/m2. Exclusion criteria: Presence of diagnosed cardiometabolic diseases (e.g., Type 2 diabetes, hypertension, Heart Failure) Taking prescription anticoagulants Taking prescriptions or supplements that effect adipose tissue metabolism (i.e., statins, Thiazolidinediones, niacin, atypical antipsychotics, or fish oil) Pregnant or nursing Inability to provide written informed consent Smokers

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Older Adults<br> | Other: 75 gm oral glucose load<br>* Consumption of 75 gm oral glucose load in order to test nutrient responsiveness<br>|
| Active Comparator: Younger Adults<br> | Other: 75 gm oral glucose load<br>* Consumption of 75 gm oral glucose load in order to test nutrient responsiveness<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adipose tissue blood flow | blood flow will be measured in the upper body subcutaneous adipose tissue using 133 Xenon washout and reported as blood flow in ml/min/100g adipose tissue. | Baseline, pre-intervention fasting and immediately following 75 gm oral glucose load | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genomic alterations | RNA-Seq from adipose tissue biopsies | Baseline, pre-intervention fasting and immediately following 75 gm oral glucose load |