Cell Signaling and Resistance to Oxidative Stress: Effects of Aging and Exercise

August 21, 2020 updated by: Tinna Traustadottir, Northern Arizona University
Advanced age is the main risk factor for chronic diseases such as cardiovascular disease, type 2 diabetes, Alzheimer's disease and cancer. One reason may be due to decreased resistance to oxidative stress as antioxidant defenses and cell protection is reduced with aging. This has been shown in animal studies and also that the impairment can be somewhat restored with exercise. This will be the first study to test this in humans by comparing young and older inactive adults before and after an exercise intervention, a practical and cost-effective intervention that can have tremendous public health impact by lowering risk for disease and medical-related costs.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Advanced age substantially increases the risk for a host of diseases including cardiovascular disease, type 2 diabetes, Alzheimer's disease, and cancer. A major factor that appears to underlie this increased risk with age is reduced capacity to resist oxidative injury or oxidative stress. Therefore, maintaining or increasing the capacity to resist oxidative stress appears critical to the prevention of age-related disease and promotion of successful aging. One potential reason for the lower resistance to oxidative stress with age is a gradual shift in the redox state toward a more oxidized cellular environment potentially disrupting cell-signaling. Nuclear erythroid-2-p45-related factor-2 (Nrf2) is the master regulator of antioxidant defenses. Nrf2 drives expression of a host of genes involved in cellular detoxification and antioxidant defenses. There is strong evidence from animal studies that Nrf2 signaling is reduced with aging and can be at least partially restored with moderate exercise training, however the gap in current knowledge is whether these data do in fact translate to humans. This study will test the following hypotheses in young and older men and women: i) aging is associated with impaired Nrf2 signaling in response to acute exercise and ii) moderate exercise training will improve Nrf2 signaling in older, inactive individuals, and this will increase their resistance to oxidative stress. These hypotheses will be tested by comparing 25 young (18-28y) and 25 older (≥60y) inactive individuals before and after an 8-week exercise intervention (n=15 per age group) and in comparison to non-exercising age-matched control groups (n=10 per age group). Nrf2 signaling will be measured in peripheral blood mononuclear cells (PBMCs) in response to acute exercise and will include gene expression (NRF2, NQO1, HO1, GCLC), protein abundance (NRF2, KEAP1, NQO1, HO1, GCLC) and Nrf2-ARE binding capacity. Resistance to oxidative stress will be measured by plasma F2-isoprostane response to forearm ischemia/reperfusion. The results will increase understanding of the mechanisms of diminished stress resilience with aging and the plasticity of these pathways. This will determine whether targeting Nrf2 signaling will be effective for prevention or treatment of these age-related changes which has an enormous public health impact due to the potential of lowering disease risk and medical costs. An additional significance of this project is creating opportunity for undergraduate and graduate students to become involved in research, an important purpose of the Academic Research Enhancement Award (AREA) program and a mission of Northern Arizona University.

Study Type

Interventional

Enrollment (Actual)

46

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Arizona
      • Flagstaff, Arizona, United States, 86011
        • Northern Arizona University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Men and women, 18-28 years or 60 years and older
  • Competent to independently give informed consent
  • Successful completion of screening
  • No regular exercise for the past 6-months (by self-report)
  • A score below 3.0 on the Historical Lifetime Physical Activity Questionnaire

Exclusion Criteria:

  • Estrogen supplementation within the previous 6 months
  • Use of anti-oxidant supplements, in excess of standard multi-vitamins (1 tablet/day)
  • Current smoker
  • Body Mass Index (BMI) ≤33 kg/m2 (Class I Obesity)
  • Any chronic illness that could affect outcome measures, including diabetes, liver or renal disease, or cancer (other than skin cancer)
  • History of a myocardial infarction within the last 6 months, clinically significant aortic stenosis, use of cardiac defibrillator, or uncontrolled angina
  • Clinically significant arrhythmia on a resting EKG or significant EKG changes during the baseline maximal oxygen consumption (VO2 max) test
  • Any other condition that would contraindicate maximal exercise testing, including elevated blood pressure at rest (systolic BP >150 or diastolic BP >90 mm Hg on at least 2 measurements, at least 10 minutes apart) or musculoskeletal problems

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Exercise Intervention
8-weeks exercise intervention: 3-days per week for 45-55 minutes per session
24 sessions of aerobic exercise
No Intervention: Control
8-weeks control: asked not to change anything or start exercising.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cell signaling
Time Frame: 8 weeks
Nuclear Nrf2 protein content in peripheral mononuclear cells (PBMCs) in response to acute exercise
8 weeks
Resistance to oxidative stress
Time Frame: 8 weeks
F2-isoprostane response to forearm ischemia-reperfusion
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cell signaling
Time Frame: 8 weeks
GCLC protein abundance in PBMCs in response to acute exercise
8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Tinna Traustadóttir, PhD, Northern Arizona University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2017

Primary Completion (Actual)

May 30, 2020

Study Completion (Actual)

June 30, 2020

Study Registration Dates

First Submitted

January 11, 2018

First Submitted That Met QC Criteria

January 26, 2018

First Posted (Actual)

February 5, 2018

Study Record Updates

Last Update Posted (Actual)

August 26, 2020

Last Update Submitted That Met QC Criteria

August 21, 2020

Last Verified

August 1, 2020

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • R15AG055077 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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