ENhancing Exercise With LIGHT to Improve Functioning in PAD (ENLIGHTEN PAD)

ENhancing Exercise With LIGHT to Improve Functioning in PAD: the ENLIGHTEN PAD Trial

The ENLIGHTEN PAD Trial will collect preliminary data to test whether daily 660 nm light treatment of the lower extremities immediately before home-based walking exercise sessions improves six-minute walk distance at 4-month follow-up, compared to sham light, in people with lower extremity peripheral artery disease (PAD).

Study Overview

• Status: Recruiting
• Conditions: Aging; Peripheral Vascular Disease; Peripheral Artery Disease; Walking, Difficulty
• Intervention / Treatment: Device: Far red light therapy; Device: Sham light therapy; Behavioral: Home-based walking exercise

Detailed Description

The ENLIGHTEN PAD Trial will collect preliminary data to test whether daily 660 nm light treatment of the lower extremities immediately before home-based walking exercise sessions improves six-minute walk distance at 4-month follow-up, compared to sham light, in people with lower extremity peripheral artery disease (PAD) (Primary Aim #1). In Primary Aim #2, the investigators will measure the acute effect of the first treatment of 660 nm light on six-minute walk distance and on walking intensity (measured with the ActiGraph accelerometer) during the six-minute walk. In secondary and exploratory aims, the investigators will delineate biologic pathways by which 660 nm light enhances the benefits of home-based walking exercise, by measuring the effects of 660 nm light on exercise intensity during the exercise intervention and by measuring the effects of 660 nm light on plasma nitrosothiols, leg perfusion, and gastrocnemius muscle health and mitochondrial activity. Exercise intensity will be measured by the well validated ActiGraph accelerometer.

The ENLIGHTEN PAD Trial is a Phase II multi-centered randomized clinical trial. Thirty-two participants with PAD will be randomized at one of two centers: Northwestern University (PI: MM McDermott, MD) and the University of Alabama (PI: Nicole Lohr MD, PhD) to either 660 nm light + home-based exercise or sham light + home-based exercise for four months. Both groups of participants will receive the same home-based high intensity walking exercise intervention.

• Study Type: Interventional
• Enrollment (Estimated): 32
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mary McDermott, MD; Phone Number: 13125036419; Email: mdm608@northwestern.edu
• Study Contact Backup: Name: Kathryn Domanchuk; Phone Number: 312-503-6438; Email: kdomanchuk@northwestern.edu

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Recruiting
      • Northwestern University
      • Contact: Mary McDermott, MD; Phone Number: 312-503-6419; Email: mdm608@northwestern.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

First, all participants will be age 50 and older. Second, all participants will have PAD. PAD will be defined as:

1. An ABI <= 0.90 at baseline.
2. Vascular lab evidence of PAD (such as a toe brachial pressure <= 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities.
3. An ABI of >0.90 and <= 1.00 who experience a 20% or greater drop in ABI in either leg after the heel-rise test.

Exclusion Criteria:

1. Above- or below-knee amputation
2. Critical limb ischemia defined as an ABI <0.40 with symptoms of rest pain
3. Wheelchair confinement or requiring a walker to ambulate
4. Walking is limited by a symptom other than PAD
5. Current foot ulcer on bottom of foot
6. Failure to successfully complete the study run-in
7. Planned major surgery, coronary or leg revascularization during the next four months
8. Major surgery, coronary or leg revascularization or major cardiovascular event in the previous three months
9. Major medical illness including lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than six months, or cancer requiring treatment in the previous two years. [NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent, unless the cancer is located in the lower extremities. Participants who require oxygen only at night may still qualify.]
10. Mini-Mental Status Examination (MMSE) score < 23
11. Non-English speaking
12. Participation in or completion of a clinical trial in the previous three months. [NOTE: after completing a stem cell or gene therapy intervention, participants will become eligible after the final study follow-up visit of the stem cell or gene therapy study so long as at least six months have passed since the final intervention administration. After completing a supplement or drug therapy (other than stem cell or gene therapy), participants will be eligible after the final study follow-up visit as long as at least three months have passed since the final intervention of the trial.]
13. Visual impairment that limits walking ability.
14. Six-minute walk distance of <400 feet or >1700 feet.
15. Participation in a supervised treadmill exercise program or a cardiac rehabilitation program in previous three months or planning to begin a supervised treadmill exercise program or a cardiac rehabilitation program in the next five months.
16. Unwilling to avoid red light therapy outside of study participation.
17. Baseline blood pressure <100/45.
18. In addition to the above criteria, investigator discretion will be used to determine if the trial is unsafe or not a good fit for the potential participant.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Far red light therapy + home-based walking exercise; Subgroup of participants receiving home-based walking exercise and the 670 nm far red light device	Device: Far red light therapy; All participants will receive one far red light device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. An unblinded study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.; Behavioral: Home-based walking exercise; This study involves a 16 week intervention where participants will walk at home for exercise with guidance from a study coach. Participants will have 4 in-person visits in the first four weeks and then have weekly phone calls in the last 12 weeks of the intervention with their coach.
Sham Comparator: Sham therapy + home-based walking exercise; Subgroup of participants receiving home-based walking exercise and the sham light device, far red light device covered with blue filter paper to block 670 nm light, resulting in mean power generated of 0.24 mW/cm2, compared to 26.3 mW/cm2 for the intervention, a 100-fold difference.	Device: Sham light therapy; All participants will receive one sham device per leg. Participants will be asked to use their two light devices daily, exposing their bare legs to the devices for 10 minutes twice per day. An unblinded study coordinator will deliver the light devices to each participant's home, positioning the devices 15 cm behind the participant's heels, using tape on the floor to mark where the light and feet should be positioned. Twice each day, the participant flips a switch on the device to begin each session. A timer will turn off the device after 10 minutes. A power meter will measure the total time that the device was turned on. Participants will also record use of the light in a log.; Behavioral: Home-based walking exercise; This study involves a 16 week intervention where participants will walk at home for exercise with guidance from a study coach. Participants will have 4 in-person visits in the first four weeks and then have weekly phone calls in the last 12 weeks of the intervention with their coach.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Six-Minute Walk Distance	Change in six-minute walk distance	Measured at baseline and 4-month follow-up
Six-Minute Walk Distance	Change in six-minute walk distance (acute effect)	Measured immediately after the first light treatment (within 15 minutes after the first treatment, acute effect)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Six-Minute Walk Distance	Change in six-minute walk distance (chronic effect)	Measured at 4-month follow-up, 24 hours after the final treatment
Gastrocnemius Perfusion	Changes in calf perfusion at 3 Tesla measured with arterial spin labeling with MRI and post-cuff occlusion hyperemia	Measured at baseline and 4-month follow-up
Minutes of High Intensity Exercise	Change in minutes of high intensity exercise/week (measured by the ActiGraph activity monitor)	Measured at baseline and 4-month follow-up
Mean Exercise Intensity	Change in mean exercise intensity (measured by the ActiGraph activity monitor)	Measured at baseline and 4-month follow-up
Mean Exercise Intensity During Six-Minute Walk	Change in mean exercise intensity during the six-minute walk (measured by the ActiGraph activity monitor)	Measured at baseline and 4-month follow-up
Walking Impairment Questionnaire Distance Score	Participant report of difficulty walking increasingly longer distances. Score range 0-100, 100 is best	Measured at baseline and 4-month follow-up
PROMIS Mobility Score	PROMIS mobility score from administered PROMIS questionnaire. Score range is from zero to infinity and a higher score means a better outcome.	Measured at baseline and 4-month follow-up

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Walking Impairment Questionnaire Speed Score	Participant report of ability to walking increasing number of stair flights (0-100 score, 100-best)	Measured at baseline and 4-month follow-up
Walking Impairment Questionnaire Stair Climbing Score	Participant report of ability to walking increasing number of stair flights (0-100 score, 100-best)	Measured at baseline and 4-month follow-up
Short Physical Performance Battery (SPPB)	SPPB range, range 0-12, 12-best	Measured at baseline and 4-month follow-up
Plasma Nitrite	Changes in plasma abundance of nitrite	Measured before and within five minutes after the first light treatment at baseline
Plasma Nitrite	Changes in plasma abundance of nitrite	Measured before and within five minutes after the final light treatment at 4-month follow-up
Plasma Nitrosothiols	Changes in plasma abundance of nitrosothiols	Measured before and within five minutes after the first light treatment at baseline
Plasma Nitrosothiols	Changes in plasma abundance of nitrosothiols	Measured before and within five minutes after the final light treatment at 4-month follow-up
Gastrocnemius Muscle Capillary Density	Changes in gastrocnemius muscle capillary density	Measured at baseline and 4-month follow-up
Gastrocnemius Muscle Myofiber Size	Changes in gastrocnemius muscle myofiber size	Measured at baseline and 4-month follow-up
Gastrocnemius Muscle Citrate Synthase Activity	Changes in gastrocnemius muscle citrate synthase activity	Measured at baseline and 4-month follow-up
Gastrocnemius Muscle Cytochrome C Oxidase Activity	Changes in gastrocnemius muscle cytochrome c oxidase activity	Measured at baseline and 4-month follow-up
Gastrocnemius Muscle Abundance of Satellite Cells	Changes in gastrocnemius muscle abundance of satellite cells	Measured at baseline and 4-month follow-up
Gastrocnemius Muscle Abundance of Myofibers with Central Nuclei	Changes in gastrocnemius muscle abundance of myofibers with central nuclei	Measured at baseline and 4-month follow-up
Short-Form 36 (SF-36) Score (0-100 score, 100-best)	Change in score on the SF-36 from baseline to follow-up	Measured at baseline and 4-month follow-up

Collaborators and Investigators

• Sponsor: Northwestern University

Study record dates

Study Major Dates

• Study Start (Actual): August 12, 2024
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): January 31, 2027

Study Registration Dates

• First Submitted: April 30, 2024
• First Submitted That Met QC Criteria: April 30, 2024
• First Posted (Actual): May 6, 2024

Study Record Updates

• Last Update Posted (Actual): April 15, 2026
• Last Update Submitted That Met QC Criteria: April 11, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: exercise; peripheral artery disease; light therapy
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Atherosclerosis; Arteriosclerosis; Arterial Occlusive Diseases; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Peripheral Arterial Disease; Mobility Limitation; Peripheral Vascular Diseases; Motor Activity
• Other Study ID Numbers: STU00219103

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No