HealthyNCT04117191
Exploring the Mechanisms of Indoxyl Sulfate Production by Oral Tryptophan Challenge Test
A study testing Doctor's Best L-Tryptophan in people with Healthy and Chronic Kidney Diseases, run by Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation at 1 site in Taiwan.
Trial summary
Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD) and is associated with extremely poor prognosis. Traditional risk factors for the general population, such as diabetes mellitus, high blood pressure, and dyslipidemia, are more common in patients with CKD but cannot fully explain… Read more about this study
- Who is it for?
- Ages 20 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Chronic Kidney Diseases
- What is being tested?
- Doctor's Best L-Tryptophan
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 42 participants
- Where
- 1 siteTaiwan
- Study dates
- 1 Oct 2019to 30 Nov 2019
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 20 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- (1) age older than 20 years
- (2) no exposure to antibiotics or probiotics within the 3 months before entering the study.
Who cannot join
- (1) recent gastrointestinal discomfort (such as nausea, vomiting, abdominal pain, constipation, or diarrhea) or
- (2) a history of chronic diseases including diabetes mellites, hypertension, CVD, CKD, liver disease, malignancy, and autoimmune disease.
- (3) pregnancy or breast feeding
- (4) currently use of antipsychotics, Hypnotics, Demerol, Dextromethorphan, tramadol, pentazocine
Trial locations and contacts
1 site in 1 country.
About this study
Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD) and is associated with extremely poor prognosis. Traditional risk factors for the general population, such as diabetes mellitus, high blood pressure, and dyslipidemia, are more common in patients with CKD but cannot fully explain the increased risk of this population. New evidence suggests that the uremic milieu itself plays a critical role in the development and progression of CVD. The gut microbiota is markedly altered in CKD, with overgrowth of bacteria that produce uremic toxins. Indoxyl sulfate (IS) is among the most representative gut-derived uremic toxins and has been most frequently implicated as a contributor to the pathogenesis of CVD in CKD. IS is converted from indole, a gut bacteria metabolite of dietary tryptophan, by two hepatic enzymes, CYP2E1 and SULT1A1. The majority of studies have assessed IS toxicity in cultured cells and animal models. However, human data have been conflicting and the benefit of using orally administered adsorbents to reduce IS levels in unselected CKD patients was not supported by results from the recent randomized controlled trials. IS levels may fluctuate widely from time to time with dietary intakes. The investigators hypothesize that a postprandial IS concentration may more reflect its toxicity than a single time point (fasting or predialysis IS) concentration measured in clinical studies. Therefore, the investigators plan to establish an oral tryptophan challenge test (OTCT) by using an oral loading of 2 gm tryptophan to simulate the postprandial increase of plasma IS. The investigators will recruit 60 healthy volunteers to undergo OTCT. A pharmacokinetic study of IS after the OTCT will be performed in 20 of them to verify and simplify the design of OTCT protocol. The results of OTCT will be integrated with whole metagenome analysis of fecal microbiota and genetic polymorphism analysis of CYP2E1 and SULT1A1 to explore the mechanisms of IS production. In addition to the known genes in microbe produces indoles, other supporting bacteria or genes will be examined by using metagenomic shotgun sequencing data.
- Conditions
- Healthy, Chronic Kidney Diseases
- Being tested
- Doctor's Best L-Tryptophan
- Medical subject headings
- Renal Insufficiency, Chronic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Doctor's Best L-TryptophanDietary supplement
2g tryptophan loading once
| Study group | Role | What they receive |
|---|---|---|
| Tryptophan loading | Experimental | All participants are introduced to receive tryptophan loading test. Receives: Dietary Supplement: Doctor's Best L-Tryptophan |
What is being measured
The primary outcome is the main question the study is designed to answer.
Indoxyl sulfate
serum and urine indoxyl sulfate concentration measurement
Measured: the area under curve of serum and urine indoxyl sulfate within 72 hours
Secondary outcomes (1)
Indole-3-acetic acid
serum and urine Indole-3-acetic acid concentration measurement
Measured: the area under curve of serum and urine Indole-3-acetic acid within 72 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2019
- Study start1 Oct 2019
- Primary completion30 Nov 2019
- Study completion30 Nov 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- All the participants would be introduced to receive 2g tryptophan loading for exploring serum and urine indoxyl sulfate concentration.
- Masking
- None (open label)
- Enrolment
- 42 participants (actual)
Sponsor and investigators
- Lead sponsor
- Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ting-Yun Lin, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation
- Investigators
- Ting-Yun Lin, MD., Principal investigator, Taichung Tzu Chi Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04117191
- Sponsor's protocol ID
- 08-P-055
- Status last verified
- Dec 2019
- First submitted
- 29 Sep 2019
- Last updated
- 10 Dec 2019
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Dec 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Exploring the Mechanisms of Indoxyl Sulfate Production by Oral Tryptophan Challenge Test
- ClinicalTrials.gov ID
- NCT04117191
- Acronym / sponsor ID
- 08-P-055
- Conditions
- Healthy, Chronic Kidney Diseases
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 42 participants (actual)
- Lead sponsor
- Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical FoundationUniversity, hospital or other
- Study start
- 1 Oct 2019 (actual)
- Primary completion
- 30 Nov 2019 (actual)
- Study completion
- 30 Nov 2019 (actual)
- First posted
- 7 Oct 2019 (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.
Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD) and is associated with extremely poor prognosis. Traditional risk factors for the general population, such as diabetes mellitus, high blood pressure, and dyslipidemia, are more common in patients with CKD but cannot fully explain the increased risk of this population. New evidence suggests that the uremic milieu itself plays a critical role in the development and progression of CVD. The gut microbiota is markedly altered in CKD, with overgrowth of bacteria that produce uremic toxins. Indoxyl sulfate (IS) is among the most representative gut-derived uremic toxins and has been most frequently implicated as a contributor to the pathogenesis of CVD in CKD. IS is converted from indole, a gut bacteria metabolite of dietary tryptophan, by two hepatic enzymes, CYP2E1 and SULT1A1. The majority of studies have assessed IS toxicity in cultured cells and animal models. However, human data have been conflicting and the benefit of using orally administered adsorbents to reduce IS levels in unselected CKD patients was not supported by results from the recent randomized controlled trials. IS levels may fluctuate widely from time to time with dietary intakes. The investigators hypothesize that a postprandial IS concentration may more reflect its toxicity than a single time point (fasting or predialysis IS) concentration measured in clinical studies. Therefore, the investigators plan to establish an oral tryptophan challenge test (OTCT) by using an oral loading of 2 gm tryptophan to simulate the postprandial increase of plasma IS. The investigators will recruit 60 healthy volunteers to undergo OTCT. A pharmacokinetic study of IS after the OTCT will be performed in 20 of them to verify and simplify the design of OTCT protocol. The results of OTCT will be integrated with whole metagenome analysis of fecal microbiota and genetic polymorphism analysis of CYP2E1 and SULT1A1 to explore the mechanisms of IS production. In addition to the known genes in microbe produces indoles, other supporting bacteria or genes will be examined by using metagenomic shotgun sequencing data.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- All the participants would be introduced to receive 2g tryptophan loading for exploring serum and urine indoxyl sulfate concentration.
| Arm | Type | Receives |
|---|---|---|
| Tryptophan loading | Experimental | Dietary Supplement: Doctor's Best L-TryptophanAll participants are introduced to receive tryptophan loading test. |
Who may qualify
- Ages
- 20 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- (1) age older than 20 years
- (2) no exposure to antibiotics or probiotics within the 3 months before entering the study.
Key exclusion criteria (4 listed)
- (1) recent gastrointestinal discomfort (such as nausea, vomiting, abdominal pain, constipation, or diarrhea) or
- (2) a history of chronic diseases including diabetes mellites, hypertension, CVD, CKD, liver disease, malignancy, and autoimmune disease.
- (3) pregnancy or breast feeding
- (4) currently use of antipsychotics, Hypnotics, Demerol, Dextromethorphan, tramadol, pentazocine
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 |
|---|---|---|
| Doctor's Best L-Tryptophan2g tryptophan loading once | Dietary supplement | Tryptophan loading |
Primary outcome
Indoxyl sulfate
Time frame: the area under curve of serum and urine indoxyl sulfate within 72 hours
serum and urine indoxyl sulfate concentration measurement
1 secondary outcome
Indole-3-acetic acid
Time frame: the area under curve of serum and urine Indole-3-acetic acid within 72 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Dec 2019.
- Individual participant dataSharing planned: No
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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.
Ting-Yun Lin, MD. principal investigator
Taichung Tzu Chi Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Doctor's Best L-Tryptophan in people with Healthy and Chronic Kidney Diseases, run by Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation at 1 site in Taiwan.
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 4 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: finished, as of the sponsor's last update on 10 Dec 2019. 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 Taiwan. 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.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Indoxyl sulfate (time frame: the area under curve of serum and urine indoxyl sulfate within 72 hours). 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 10 Dec 2019.