Defining the Effect of Gastric Electrical Stimulation on Serum Insulin Levels in Human Subjects

Investigating the Effect of Gastric Electrical Stimulation (GES) on Hormone Levels

Primary Investigator
T

Thomas Nowak, MD

Primary Investigator

Enrolling By Invitation
18 years - 100 years
All
Phase N/A
15 participants needed
1 Location

Brief description of study

The purpose of this study is to determine if hormone levels (Insulin, Glucose, C-peptide, and GLP-1) are significantly affected by turning off the Gastroelectric Stimulator device, for up to 4 hours, in individuals that have gastroparesis with a Stimulator implanted, and are not on any insulins. Researchers would also like to determine if the changes in hormone levels in said individuals also affect heart rate variability and the sympathetic and para-sympathetic nervous systems.

THIS STUDY IS ENROLLING BY INVITATION ONLY - Subjects will be recruited from existing patients who are seen at the IU University Hospital Digestive and Liver Disorders clinic. They will be preliminarily evaluated by the Primary Investigator and approached by the PI to explain the study and to see if the subject would be interested. The subjects would then be refered to the Clinical Research Coordinator. The research coordinator will organize a time to screen the patient for eligiblity. Subjects who are being seen in clinic for gastroparesis and have undergone the GES implantation will be enrolled.

Detailed description of study

This study will evaluate male and female patients at least 18 years of age, with gastroparesis, who have already undergone the implantation of a GES device (Enterra, Medtronic, Minneapolis, MN)

  • Identified patients will be asked to not have anything to eat or drink past 10 PM the night before the study appointment.  They can take some water and medications as needed. The patients will physically sign the consent document on the day of the visit before the start of any study procedures.
  • Subjects will be asked to fill out a symptom survey at the visit.
  • EKG Electrodes will be placed on chest, neck and auricular vagal nerve.
  • A butterfly catheter will be placed, and the first 5 ml blood sample will be taken and labeled as Baseline.
  • After a 20-minute baseline the second 5ml blood draw will be taken and the subject’s GES will be turned to the OFF setting, then the 4-hour Experimental session begins with blood samples labeled as: 30-minute Experimental, 1-hour Experimental, and so on up to hour 4. EKG recordings are continuing.
  • After the 4-hour mark, the GES is turned to ON and a final 20-minute Recovery period is recorded.
  • After the 20-minute recovery period, the final 5 ml blood draw is done and the IV line is removed, patient is bandaged. Recordings are then completed and saved, EKG electrodes are removed, and the patient will have finished the procedure.
     

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Gastroparesis
  • Age: 18 years - 100 years
  • Gender: All

Inclusion Criteria

•    At least 18 years of age.
•    Documented diagnosis of gastroparesis 
•    Not taking diabetic prescribed exogenous insulin.
•    Patient has a GES device that has been implanted for at least 3 months
•    Willing to give up to 8 blood samples.
•    Willing to lie in a bed for up to 5.5 hours.

Exclusion Criteria

•    Pregnancy
•    History of allergic reaction to EKG lead placement adhesives.
•    Unable to give informed consent.
•    Unwilling to give up to 8 5 ml blood samples.
•    Unwilling to lie in a bed for up to 5.5 hours.
 

This study investigates the effect of turning off a gastric electrical stimulator (GES) on hormone levels in people with gastroparesis. Gastroparesis is a condition where the stomach cannot empty food properly. The purpose of this study is to see if turning off the GES device affects hormones like insulin and glucose, and if these changes influence heart rate and the nervous system.

Participants will not eat or drink after 10 PM the night before the study. They will sign a consent form and fill out a symptom survey. Electrodes will be placed for heart monitoring, and a catheter will be used for blood samples. The GES device will be turned off for 4 hours during which multiple blood samples will be taken. Afterward, the device is turned back on and a final blood sample is collected.

  • Who can participate: Adults aged 18 and older with gastroparesis who have had a GES device for at least 3 months and are not on insulin can participate. They must be willing to provide blood samples and stay in bed for 5.5 hours.
  • Study details: Participants will have up to 8 blood samples taken and will need to lie down for up to 5.5 hours. They will undergo heart monitoring with electrodes and will have a catheter for blood draws.
Updated on 06 Aug 2026. Study ID: 30020
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Interested in the study?

This study is accepting only persons who receive care at a certain clinic or doctor or who are part of an invited group. Questions about this study can be directed to the study team listed in the description or contact your doctor to see if you are eligible.

Accepting Referrals by Invitation Only