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Cardiovascular DiseasesNCT05135702

Effect of Propionic Acid Supplementation on Endothelial Function

A study testing Sodium Propionate in people with Cardiovascular Diseases and Endothelial Dysfunction, run by Medical College of Wisconsin.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

Coronary Artery Disease (CAD) remains a leading cause of morbidity and mortality worldwide despite improved mitigation of traditional risk factors. Large association studies have linked the gut microbiome alterations with inflammation, CAD, and traditional CAD risk factors. Read more about this study

Who is it for?
Ages 40 to 75 years
What is being tested?
Sodium Propionate
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
20 participants
Where
No sites listed yet
Study dates
Jul 2027to Dec 2029
Phase
Interventional
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 40 to 75 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • History of known coronary artery disease as defined by having one or more of the following:
  • history of myocardial infarction
  • angiogram demonstrative >=50% stenosis in at least 1 major epicardial coronary artery
  • a previous stress test that showed evidence of ischemia (that has not been revealed to be a false positive test by angiography)
  • CT coronary study showing EITHER a coronary artery calcium (CAC) score of >400, OR a description of "significant stenosis" of one or more epicardial arteries.

Who cannot join

  • Unstable angina or myocardial infarction by history, ECG, and/or enzymatic criteria within 1 month of enrollment.
  • LV dysfunction as defined by an LV ejection fraction documented as < 45% within 1 year of enrollment by an echocardiogram, MRI, or nuclear imaging.
  • Uncontrolled hypertension with a blood pressure greater than 170/100 mmHg at the screening visit.
  • Known history of chronic renal insufficiency, liver dysfunction, or cancer besides non-melanoma skin carcinomas or localized prostate cancer requiring systemic treatment within five years of enrollment.
  • Known history of cognitive impairment or inability to follow study procedures.
  • Patient with GI tract illness such as short gut syndrome, inflammatory bowel disease, or an ileostomy.
Show all 12Show fewer
  • Patient with an implanted defibrillator or permanent pacemaker on which the potential participant is known to rely upon for greater than 50% of ventricular depolarizations.
  • Patients who received probiotics, prebiotics, or short chain fatty acid supplements (e.g. propionate, butyrate, acetate-containing supplements) within the past 4 weeks.
  • Patients who received antibiotics in the last 12 weeks.
  • Patients with dosing changes of vasoactive medications and HMG-CoA reductase inhibitors in the 6 weeks prior to enrollment.
  • Pregnancy
  • Those who are daily drinkers or use illicit drugs.

Trial locations and contacts

No sites are listed yet. Contact the study team or a site near you to ask about taking part.

Michael E Widlansky, MD, MPH contact

4149556759

mwidlans@mcw.edu

Benjamin C Hofeld, MD contact

4149556759

bhofeld@mcw.edu

About this study

Official title: Effect of Propionic Acid Supplementation on Endothelial Function in Patients With Coronary Artery Disease

Coronary Artery Disease (CAD) remains a leading cause of morbidity and mortality worldwide despite improved mitigation of traditional risk factors. Large association studies have linked the gut microbiome alterations with inflammation, CAD, and traditional CAD risk factors. Subsequent studies have shown concomitant improvements in gut dysbiosis, inflammation, and cardiometabolic diseases using probiotics and other gut-modulating therapies. To date, many studies have shown a correlative relationship between intestinal bacteria composition and the presence of CAD, or severity of heart attacks, but few have begun to elucidate potential metabolic and immunologic mechanisms.

The investigator's recently supplemented Lactobacillus plantarum 299v in men with stable CAD, which improved systemic inflammation and brachial artery flow-mediated dilation (BA-FMD) - a measure of endothelial function and a predictive CAD precursor. Improvement in BA-FMD positively correlated with increased serum propionic acid (PA) concentrations. PA is a gut microbiome-derived short chain fatty acid (SCFA) with known human vascular receptors and implicated in endothelial function, innate immunity, and glucose homeostasis.

Read more

Whether PA is mediating improvement in endothelial dysfunction or inflammation in the investigator's prior experiment remains unknown. The investigator's objective is to determine whether endothelial cell function is improved by dietary supplementation of sodium propionate in patients with established coronary artery disease. Furthermore, the investigators wish to elucidate to what extent inflammation is reduced by this therapy, by both measuring serum inflammatory markers and by seeing if plasma from treated patients induces anti-inflammatory transcriptomic responses from cultured endothelial cells and peripheral blood mononuclear cells, both of which are involved in atherosclerosis.

Specific Aim 1 will determine the impact of dietary PA supplementation on endothelial function and traditional CAD risk factors in patients with CAD. The investigators will utilize ultrasound to assess the percent change in BA-FMD before and after dietary PA supplementation. The extent of endothelium-dependency of these responses will be tested by measuring BA-FMD following nitroglycerin administration. The investigators will also measure markers representative of traditional CAD risk factors, such as lipid levels and HgbA1C.

Specific Aim 2 will determine anti-inflammatory changes in vivo and in transcriptomic signatures of cultured EC and PBMCs induced by dietary PA. The investigators will measure changes to systemic serum inflammatory markers involved in atherosclerotic processes using a targeted metabolomics approach, using plasma from the investigator's cohort before and after PA supplementation. Plasma samples will be used to incubate aforementioned cells to compare transcriptomic signatures of cells subjected to pre-supplementation plasma versus post-supplementation plasma. The investigators will use Ingenuity Pathway Analysis to determine changes to inflammatory pathways and i.i.com to determine whether more anti-inflammatory signatures were induced.

Specific Aim 3 will determine the impact of PA supplementation on gut microbiome taxonomy and diversity. As an optional additional clinical study activity, the investigators will collect stool samples before and after dietary PA supplementation, subject samples to multiplex 16S RNA sequencing, and calculate the Shannon Diversity Index. This will help us determine changes in individual gut microbiome constituents and diversity of the entire population.

Read the detailed description

Endothelial dysfunction (ED) is a pathological state of vessel function characterized by increased expression of pro-vasoconstrictive mediators and increased thrombotic risk. ED is associated with the development of atherosclerosis, including coronary artery disease (CAD), and with increased risk of cardiovascular events Therefore, there is an ongoing research effort to restore endothelial function in order to reduce the risk of cardiovascular morbidity associated with endothelial dysfunction.

The gut microbiome has been well correlated with the presence of CAD and alterations to the gut microbiome have been mechanistically linked to the severity of myocardial infarction. Animal experiments showed that alteration of gut bacteria with supplementation of Lactobacillus plantarum 299v (Lp299v) and vancomycin is associated with reduced leptin levels, size of myocardial infarction and improved post -ischemic cardiac function. In humans, dietary supplementation with Lp299v was associated with significant reductions in LDL-cholesterol, fibrinogen, and leptin concentrations in smokers.The investigatorsrecently showed in men with stable CAD that six weeks' supplementation with Lp299v improved endothelial function as assessed by brachial artery flow-mediated dilation (BA-FMD), a widely accepted noninvasive modality of assessing vascular endothelial function. This intervention concurrently reduced serum inflammatory markers IL-8, IL-12 and leptin, and post-probiotic plasma drove an anti-inflammatory transcriptomic response in cultured peripheral blood mononuclear cells. Interestingly, these beneficial changes were not accompanied by changes in gut microbiome constituents. Instead, the increase seen in BA-FMD was positively correlated with an increase in serum propionic acid, one of the short-chain fatty acids, a set of molecules produced by gut microbes and freely absorbed into human circulation. Propionic acid is known to improve endothelial function, reduce systemic inflammation, and improve glucose homeostasis in several models. These experiments suggested that Lp299v's beneficial effects were mediated by changes to the existing gut microbiome's metabolism as opposed to changes to microbial constituents. The investigators identified propionic acid as a potential mediator of these beneficial outcomes.

In this study, the investigator's objective is to assess if there is any impact of sodium propionate dietary supplementation on vascular endothelial function and on the levels of circulating inflammatory markers related to endothelial dysfunction. In addition, the investigators also will study if the impact on endothelial function is associated with either: anti-inflammatory changes in relevant vascular cell types (e.g. endothelial cells, peripheral blood mononuclear cells), or on the constituents of the gut microbiome itself.

Endothelial function is easily measurable by non-invasive means. Endothelial dysfunction measured non-invasively independently predicts future cardiovascular risk in patients both with and without clinically apparent cardiovascular disease. Conduit vessel endothelial function in humans is commonly quantified by measurement of BA-FMD, which represents the endothelium-dependent relaxation of a conduit artery-typically the brachial artery - due to an increased blood flow. BA-FMD correlates with impaired endothelium-dependent relaxation in the coronary arteries and is a commonly recognized "barometer" of cardiovascular risk. BA-FMD is an ideal surrogate marker of cardiovascular risk to monitor the acute impact of Lp299v supplementation on vascular endothelial function.

Being tested
Sodium Propionate, Placebo
Medical subject headings
Cardiovascular Diseases

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Sodium PropionateDietary supplement

    a 500 mg powder dietary supplement that can be mixed into food or drinks. It will be taken twice daily for four weeks.

  • PlaceboDietary supplement

    a color, size, calorie, and consistency-matched powder dietary supplement that can be mixed into food or drinks. It will be taken twice daily for four weeks.

Study groups in NCT05135702
Study groupRoleWhat they receive
Sodium Propionate FirstExperimentalSubjects in this arm will consume 500mg sodium propionate powder twice daily for four weeks, mixed into their food/drink. This is followed by four weeks of placebo twice daily.
Receives: Dietary Supplement: Sodium Propionate; Dietary Supplement: Placebo
Placebo FirstPlacebo comparatorSubjects in this arm will consume a placebo twice daily for four weeks, mixed into their food/drink. This is followed by four weeks of 500mg sodium propionate powder, twice daily.
Receives: Dietary Supplement: Sodium Propionate; Dietary Supplement: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in baseline flow mediated dilation (FMD) at 4 weeks

    This is a measurement of endothelial function in the brachial artery

    Measured: baseline and week 4

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted26 Nov 2021
  2. Study startJul 2027 (estimated)
  3. Primary completionJul 2029 (estimated)
  4. Study completionDec 2029 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
20 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05135702
Sponsor's protocol ID
PRO39540
Status last verified
Sep 2025
First submitted
15 Nov 2021
Last updated
25 Sep 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Questions about this trial

What is this clinical trial studying?

A study testing Sodium Propionate in people with Cardiovascular Diseases and Endothelial Dysfunction, run by Medical College of Wisconsin.

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 5 inclusion and 12 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: opening soon, as of the sponsor's last update on 25 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

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?

Contact Michael E Widlansky, MD, MPH (4149556759, mwidlans@mcw.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in baseline flow mediated dilation (FMD) at 4 weeks (time frame: baseline and week 4). 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 25 Sep 2025.

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