Expandability of Aging Adipose Tissue

Study Overview
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Brief Summary
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The purpose of this pilot study is to determine whether adipose tissue loses some of its ability to expand in response to overfeeding in older compared to younger men. The investigators hypothesize that the adipose tissue response to overfeeding may be weakened in older when compared to younger men, thereby leading to worsened ectopic storage depots for older men.

Detailed Description
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This pilot study will begin to address whether adipose tissue biology changes with advancing age. Specifically, we will test whether adipose tissue loses some of its ability to expand in response to overfeeding in older compared to younger men. To test this possibility the Investigators will recruit overweight and mildly obese older (age 55-75y) and younger (age 25-40y) men and collect adipose tissue biopsies before and after 7 days of overfeeding. The investigators will test how well the cells in adipose tissue expand in response to overfeeding and whether this differs between younger and older men.

Official Title
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Aging Subcutaneous Adipose Tissue Response to Overfeeding

Conditions
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Aging, Obesity

Intervention / Treatment
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* Other: Overfeeding


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men Aged 25-40y OR 55-75y BMI 28-35 kg/m2 Weight stable (±2kg over past 3 mo) Sedentary to moderately active (<3 d/wk of exercise lasting >20min) Non-smokers (never used or quit >7yrs prior) Exclusion Criteria: Women Currently using hormones, glucose or lipid lowering medication Engaged in exercise or diet program Currently gaining or losing weight or using weight loss drugs Diabetes mellitus (diagnosis, treatment, FBG ≥126 mg/dL) Uncontrolled metabolic disorders (e.g., thyroid)

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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Male

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: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: MA<br>Middle-aged overweight and obese men (age 25-40yr) | Other: Overfeeding<br>* Consumption of 40% excess calories for 7 consecutive days<br>|
| Other: OA<br>Older overweight and obese men (age 55-75yr) | Other: Overfeeding<br>* Consumption of 40% excess calories for 7 consecutive days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in adipose-derived stem cell (ASC) differentiation (Delta%oil red O+) | age-related difference in the ASC differentiation response to overfeeding | 1 wk of overfeeding | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in ASC proliferation (Delta rate of cell growth) | age-related difference in the ASC proliferative response to overfeeding | 1 wk of overfeeding | 
| Change in expression of C/EBPalpha, C/EBPbeta, PPARgamma2, SREBP1c, SREBf1a, and Wnt10b (fold-changes in mRNA expression) | age-related difference in the pro-adipogenic response to overfeeding | 1 wk overfeeding | 
| Change in intramyocellular (IMCL) di-saturated diacylglycerol (DAG) localization (Delta %membrane:cytosol) | age-related difference in the IMCL DAG response to overfeeding | 1 week overfeeding | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Adipose tissue, Overfeeding