AgingEarly Phase 1NCT06633198
Heat, Microvascular Function and Aging
A Early Phase 1 study testing Passive Heating and L-NAME in people with Aging, run by William Hughes at 1 site in United States.
Trial summary
Vascular dysfunction is a common factor in many chronic debilitating diseases, contributing to morbidity and mortality. With the onset of chronic disease or exposure to stress, the vasculature displays an inability to adequately respond to increased blood flow demands, manifesting in a reduced ability or altered… Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Aging
- What is being tested?
- Passive Heating and L-NAME
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 1 May 2025to 31 Dec 2028
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Participants must be between 18-80 yrs. of age
- No more than 1 cardiovascular risk factor (see list in exclusion criteria)
Who cannot join
- Cardiovascular Risk Factors
- Uncontrolled/unmanaged hypertension and/or use of current anti-hypertensive therapy
- Current Tobacco product use or within last 6 months
- BMI greater than 30
- Hyperlipidemia - diagnosed and/or taking medications to manage
- Hypercholesterolemia - diagnosed and/or taking medications to manage (e.g. statins)
Show all 30Show fewer
- Type 1 or Type 2 Diabetes
- Use of anti-coagulant or anti-platelet drugs
- Use of beta blockers
- Symptomatic coronary artery disease
- Diagnosed Heart Failure (Any classification above Class I as defined by NY Heart Association)
- Diagnosed renal impairment Renal impairment defined, according to National Kidney Foundation as abnormalities of kidney structure or function, present for greater than 3 months, including:
- Albuminuria (ACR ≥ 30 mg/g)
- Urine sediment abnormalities
- Electrolyte and other abnormalities due to tubular disorders
- Structural abnormalities detected by imaging
- History of kidney transplantation
- Decreased glomerular filtration rate (GFP \< 60 mL/min/1.73 m2)
- Current Hormone Replacement Therapy Use
- History of retinopathy
- Documented neuromuscular disorders
- Porphyria Cutanea Tarda (blistering of skin to sun; photosensitivity)
- Pregnancy (Young Female subjects)
- Allergies to povidone iodine
- Tattoos on lower arm (forearm)
- Use of erectile dysfunction medication in the past 6 months
- Use of topical/non-topical steroids in last 6 months (e.g. cortisone cream)
- Active anti-cancer treatment or treatment within last 12 months
- Active COVID-19 or within the past 3 months
- Gender Reassignment Therapy
Trial locations and contacts
1 site in 1 country.
United States1 site
Medical College of Wisconsin
Milwaukee, Wisconsin, 53226
About this study
Vascular dysfunction is a common factor in many chronic debilitating diseases, contributing to morbidity and mortality. With the onset of chronic disease or exposure to stress, the vasculature displays an inability to adequately respond to increased blood flow demands, manifesting in a reduced ability or altered mechanism of vasodilation. Aging is an independent risk factor in the development of cardiovascular disease, and reduces vasodilator capacity, or alters the mechanism by which vasodilation occurs in multiple vascular beds. Chronic exercise/physical activity is one of the most potent ways to enhance vascular function, resulting in favorable outcomes such as reductions in blood pressure, and improved ability to perform activities of daily living. Barriers to exercise or failure of long-term adherence preclude many populations from the cardiovascular benefits of exercise, thus further enhancing cardiovascular risk. Avenues to mimic blood flow patterns observed with exercise may exert beneficial effects without the need for the ability to exercise. Recent evidence has demonstrated that passive heat therapy, or chronic heat exposure (~ +1°C in core temperature) results in reductions in major adverse cardiovascular events, blood pressure and improved large artery endothelial function, primarily through preservation of large artery function in response to vascular stress. It is unclear whether microvascular function is augmented in response to acute heat exposure, or whether this can protect against vascular insults particularly in older adults. Some preliminary evidence in humans suggest that autophagy, a cell recycling process is involved in the beneficial cardiovascular effects, as short-term heat exposure upregulates markers of autophagy. Previous evidence from our lab indicates that autophagy governs the mechanism by which microvascular vasodilation occurs. The role of autophagy in mediating the beneficial effects of passive heating is unknown.
- Conditions
- Aging
- Being tested
- Passive Heating, L-NAME
- Keywords
- Passive heating, Aging, Microvascular, Autophagy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Passive HeatingProcedure or surgery
The lower limbs will be immersed in warm (42C) circulating water for 60 minutes.
L-NAMEDrug
L-NAME will be used during measurement of cutaneous microvascular function to test the dependency upon NO to elicit vasodilation.
| Study group | Role | What they receive |
|---|---|---|
| Passive Heating of lower limbs | Experimental | The lower limbs will be immersed in warm circulating water for 60 minutes. Receives: Procedure: Passive Heating; Drug: L-NAME |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in cutaneous microvascular function
Change in cutaneous microvascular function assessed via microdialysis infusion of acetylcholine (dose response) in the presence and absence of L-NAME to test the dependency upon NO to elicit vasodilation.
Measured: Baseline, 60 minutes post I/R, and 60 minutes post hot water immersion + I/R injury
Secondary outcomes (3)
Spontaneous baroreflex sensitivity
Change in spontaneous BRS
Measured: Baseline, 60 minutes post I/R, 60 minutes post hot water immersion + I/R injury
24-hour (Ambulatory) Blood Pressure
Ambulatory blood pressure (systolic, diastolic) for both peripheral and aortic blood pressure
Measured: Baseline
Change in plasma concentration of heat shock proteins
Change in the plasma concentrations of various heat shock proteins (HSP 70, 90)
Measured: Baseline and 60 minutes post hot water immersion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Oct 2024
- Study start1 May 2025
- Primary completion31 Dec 2028 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AgingStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- William Hughes
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, William Hughes, Medical College of Wisconsin
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06633198
- Sponsor's protocol ID
- PRO00052867
- Status last verified
- Jul 2026
- First submitted
- 4 Oct 2024
- Last updated
- 9 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 9 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Heat, Microvascular Function and Aging
- ClinicalTrials.gov ID
- NCT06633198
- Acronym / sponsor ID
- PRO00052867
- Conditions
- Aging
- Keywords
- Passive heating, Aging, Microvascular, Autophagy
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- William HughesUniversity, hospital or other
- Study start
- 1 May 2025 (actual)
- Primary completion
- 31 Dec 2028 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 9 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Vascular dysfunction is a common factor in many chronic debilitating diseases, contributing to morbidity and mortality. With the onset of chronic disease or exposure to stress, the vasculature displays an inability to adequately respond to increased blood flow demands, manifesting in a reduced ability or altered mechanism of vasodilation. Aging is an independent risk factor in the development of cardiovascular disease, and reduces vasodilator capacity, or alters the mechanism by which vasodilation occurs in multiple vascular beds. Chronic exercise/physical activity is one of the most potent ways to enhance vascular function, resulting in favorable outcomes such as reductions in blood pressure, and improved ability to perform activities of daily living. Barriers to exercise or failure of long-term adherence preclude many populations from the cardiovascular benefits of exercise, thus further enhancing cardiovascular risk. Avenues to mimic blood flow patterns observed with exercise may exert beneficial effects without the need for the ability to exercise. Recent evidence has demonstrated that passive heat therapy, or chronic heat exposure (~ +1°C in core temperature) results in reductions in major adverse cardiovascular events, blood pressure and improved large artery endothelial function, primarily through preservation of large artery function in response to vascular stress. It is unclear whether microvascular function is augmented in response to acute heat exposure, or whether this can protect against vascular insults particularly in older adults. Some preliminary evidence in humans suggest that autophagy, a cell recycling process is involved in the beneficial cardiovascular effects, as short-term heat exposure upregulates markers of autophagy. Previous evidence from our lab indicates that autophagy governs the mechanism by which microvascular vasodilation occurs. The role of autophagy in mediating the beneficial effects of passive heating is unknown.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Passive Heating of lower limbs | Experimental | Procedure: Passive Heating, Drug: L-NAMEThe lower limbs will be immersed in warm circulating water for 60 minutes. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Participants must be between 18-80 yrs. of age
- No more than 1 cardiovascular risk factor (see list in exclusion criteria)
Key exclusion criteria (30 listed)
- Cardiovascular Risk Factors
- Uncontrolled/unmanaged hypertension and/or use of current anti-hypertensive therapy
- Current Tobacco product use or within last 6 months
- BMI greater than 30
- Hyperlipidemia - diagnosed and/or taking medications to manage
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Passive HeatingThe lower limbs will be immersed in warm (42C) circulating water for 60 minutes. | Procedure or surgery | Passive Heating of lower limbs |
| L-NAMEL-NAME will be used during measurement of cutaneous microvascular function to test the dependency upon NO to elicit vasodilation. | Drug | Passive Heating of lower limbs |
Primary outcome
Change in cutaneous microvascular function
Time frame: Baseline, 60 minutes post I/R, and 60 minutes post hot water immersion + I/R injury
Change in cutaneous microvascular function assessed via microdialysis infusion of acetylcholine (dose response) in the presence and absence of L-NAME to test the dependency upon NO to elicit vasodilation.
3 secondary outcomes
Spontaneous baroreflex sensitivity
Time frame: Baseline, 60 minutes post I/R, 60 minutes post hot water immersion + I/R injury
24-hour (Ambulatory) Blood Pressure
Time frame: Baseline
Change in plasma concentration of heat shock proteins
Time frame: Baseline and 60 minutes post hot water immersion
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jul 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Passive Heating and L-NAME in people with Aging, run by William Hughes at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 30 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 9 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in cutaneous microvascular function (time frame: Baseline, 60 minutes post I/R, and 60 minutes post hot water immersion + I/R injury). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jul 2026.