Taking people in United StatesPhase 2

Blood pooling in the gut after glucose in postural tachycardia syndrome

Studies how glucose and a GIP blocker affect gut blood pooling in POTS.

Key facts

Who runs it: Vanderbilt University Medical Center
Where: Nashville, United StatesSee the site
Trial code: NCT05375968
Registry title: Splanchnic Venous Capacitance in Postural Tachycardia Syndrome
Status: Recruiting
Phase: Phase 2
People taking part: 50 people, planned
Started: 25 Feb 2023
Expected to end: 1 Jun 2028
Type of study: Interventional, 2 groupsOne group gets an existing treatment, for comparison.
Treatments tested: Measurement of Splanchnic venous capacitance(SVC)done at Baseline and after 90 min of 75 g glucose in Healthy Controls POTS patients
Measurement of Splanchnic venous capacitance(SVC)done at Baseline and after 90 min of 75 g glucose in Healthy Controls
Compare change is SVC and SMA flow due to GIP antagonist GIP(3-30)NH2
Compare change is SVC and SMA flow due to saline
Record updated: 5 December 2025

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with POTS who get faint-like symptoms after meals, and healthy people as a comparison group.

Age: 18 to 50 years
Sex: All sexes
Disease stage: People with POTS (Postural Tachycardia Syndrome) who feel close to fainting after meals. Healthy controls must have no significant past medical history, not smoke and take no long-term medicines.
Earlier treatment: Healthy controls cannot be on long-term medicines. People on statin therapy, oral corticosteroids or long-term acetaminophen cannot join.
Biomarker or test result: BMI between 18.5 to 29.9 kg/m2. Women before menopause must have regular periods.

Main reasons for not taking part

BMI of 30 kg/m2 or more
Heart problems, heart procedures, stents or a pacemaker
Type 1 or type 2 diabetes
Pregnant or breast-feeding women
Smokers, ongoing substance abuse, or anemia (Hematocrit<34%)

The registry criteria, word for word

Show all 28 criteriaShow less

Who can take part

Between 18 and 50years of age
Cases: Diagnosis of POTS with presyncope symptoms after meals Or; Controls:
With no significant past medical history, non-smokers and not on chronic medications
Body mass index (BMI) between 18.5 to 29.9 kg/m2
If pre-menopausal women: must have regular menstrual cycle

Who cannot take part

On statin therapy for high cholesterol
On oral corticosteroids,
Heart problems: myocardial infarction, angina, heart failure, stroke
Undergone any heart related procedures or stents or on pacemaker
Uncontrolled hypertension
Type 1 or type 2 diabetes mellitus
History of seizures
History of neck surgery
Current infections
BMI above ≥30 kg/m2
Irregular menstrual cycle
Intolerance to CPAP
Chronic use of acetaminophen
Pregnant or breast-feeding women
Impaired liver function
Impaired Kidney function test
Anemia (Hematocrit<34%)
Ongoing substance abuse
Subjects with abnormal EKG
Diagnosed with neuropathy due to any reason
Smoker,
Rheumatoid arthritis
Documented of moderate decrease in blood volume

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

Are you between 18 and 50 years old?

Where in United States

Vanderbilt University Medical CenterNashville, United StatesContact: Cyndya Shibao, MD, MSCITaking people

About the trial

What the trial wants to find out

Postural tachycardia syndrome (POTS) affects ≈3 million young people, characterized by chronic presyncopal symptoms characterized by dizziness, lightheadedness, and orthostatic tachycardia that occur while standing. Across-sectional survey found that 25% of these patients complains that meals rich in carbohydrates are among the factors that further exacerbate POTS's symptoms and cause a myriad of gastrointestinal symptoms.

Read full original descriptionShow less

The splanchnic circulation is the largest blood volume reservoir of the human body, storing ≈25% of the total blood volume and contributing to sudden, and large, fluctuations in the stroke volume (SV). The orthostatic changes in systemic hemodynamics are particularly magnified after meals, due to increased blood volume sequestration triggered by the release of gastrointestinal peptides with vasodilatory properties. The purpose of this study is to determine if the worsening orthostatic tachycardia and symptoms after glucose ingestion in POTS patients are due to a greater increase in splanchnic venous capacitance and excessive blood pooling on standing as compare to Healthy controls.

The study will also determine if glucose-induced GIP secretion increases splanchnic venous capacitance, orthostatic tachycardia and worsening POTS postprandial symptoms. For this purpose subjects will be further randomized to either saline versus GIP(3-30)NH2 acute infusion, to measure the changes their splanchnic venous capacitance and superior mesenteric arterial flow before and after a 75-g oral glucose challenge during supine and 45-degree head-up tilt positions (orthostatic challenge) for up to 3 hours.

The 2 groups in the trial

Changes in Splanchnic venous capacitance(SVC) before and after a 75-g oral glucose challengeExisting treatment, for comparison
To compare and measure changes in splanchnic venous capacitance and superior mesenteric arterial flow before and after a 75-g oral glucose challenge during supine and 45-degree head-up tilt positions (orthostatic challenge) for up to 3 hr. between participants with POTS (Postural Tachycardia Syndrome) and Healthy Control group Various GIP hormones especially GLP-1, GLP-2, glucagon, and other GI hormones before and after a 75-gram oral glucose at different timepoints through out 3 hours of the study visit
Treatment: Measurement of Splanchnic venous capacitance(SVC)done at Baseline and after 90 min of 75 g glucose in Healthy Controls POTS patients and Measurement of Splanchnic venous capacitance(SVC)done at Baseline and after 90 min of 75 g glucose in Healthy Controls
Effect of GIP antagonist GIP(3-30)NH2 Vs Saline on splanchnic venous capacitance on POTS patientsPlacebo, for comparison
POTS patients who participated in Aim 1, will be and randomized to either saline versus GIP antagonist (GIP(3-30)NH2) in Visit 2. The changes in their splanchnic venous capacitance and superior mesenteric arterial flow will be measured, before and after a 75-g oral glucose challenge during supine and 45-degree head-up tilt positions (orthostatic challenge) for up to 3 hr. Notably, changes in venous capacitance will be assessed using segmental impedance to measure the effect of graded positive airway pressure (CPAP) on splanchnic blood volume.
Treatment: Compare change is SVC and SMA flow due to GIP antagonist GIP(3-30)NH2 and Compare change is SVC and SMA flow due to saline