GastroFlow: Investigation of the Gastrointestinal Blood Flow in Patients With Postprandial Hypotension

GastroFlow: Investigation of the Gastrointestinal Blood Flow in Patients With Postprandial Hypotension

This project will describe the mechanisms of action and the relative contributions of GIP to changes in gastrointestinal blood flow induced by oral glucose and endogenous GIP with the use of a receptor antagonists GIP(3-30)NH2 in patients with postprandial hypotension.

Each participant will attend three independent randomised experimental days in the MRI-scanner with intravenous infusion (hormone/placebo) and oral ingestion (glucose): An intravenous infusion of saline or GIP(3-30)NH2 starts at time point -20 minutes.The infusions are combined with an oral glucose tolerance test (75 gram of glucose dissolved in 250 ml water ingested orally) at time point 0 minutes on two of the experimental days (with and without GIP(3-30)NH2). Furthermore one day will be with handgrip exercise, without an infusion. Therefore the first two days are in randomized order.

MRI measurements are repeatedly performed and blood samples are drawn to be analysed for endocrine responses from the intestines and pancreas.

For the PPH group

Inclusion Criteria:

• Postprandial hypotension
• Symptoms of postprandial hypotension

Exclusion Criteria:

• Treatment with drugs that cannot be paused for 12 hours
• Metallic implants that does not tolerate MRI
• Any other disease or dysfunction that may disturb blood flow to the gut
• Intake of more than 14 units of alcohol per week or abuse of drugs
• Blood vessels that are not feasible for measuring flow in the MRI scanner
• Low blood percent
• Decreased kidney function
• Decreased liver function
• Claustrophobia

For the healthy group

Inclusion Criteria:

• Matched by age, gender and BMI

Exclusion Criteria:

• Postprandial hypotension
• Metallic implants that does not tolerate MRI
• Intake of more than 14 units of alcohol per week or abuse of drugs
• Blood vessels that are not feasible for measuring flow in the MRI scanner
• Low blood percent
• Decreased kidney function
• Decreased liver function
• Claustrophobia
• Autonomic dysfunction or other disease that cause changes in blood pressure during or after a meal
• Intake of pharmaceutical products that influence the blood pressure