Importance of Liver Innervation for the Osmopressor Response in Humans

Study Overview
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Brief Summary
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In patients with autonomic dysfunction water drinking elicits a pressor response mediated by sympathetic activation. If any, in healthy subjects there is only a slight increase in blood pressure. However, the sympathetic activation is observable by resting energy expenditure increases greater than 20%. The investigators believe that the response to water may be mediated through sympathetic activation elicited by osmosensitve spinal afferents in the liver. Therefore, the investigators want to test water in liver transplant patients who have a denervated liver. Kidney transplant patients serve as control subjects. The investigators hypothesize that the increase in norepinephrine after water drinking is blunted in liver transplant recipients.

Official Title
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Importance of Liver Innervation for the Osmopressor Response in Humans

Conditions
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PHYSIOLOGICAL PHENOMENA

Intervention / Treatment
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* Dietary Supplement: 500ml water intake


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 3 to 24 month past liver or kidney transplantation age 18 to 60 written informed consent ability to understand the oral and written information Exclusion Criteria: pregnancy or lactation transplantation of another organ chronic heart or vascular disease known alcohol or drug abuse psychiatric diseases (e.g. chronic depression, schizophrenia, drug addiction)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: liver transplanted patients<br>Target group to confirm the hypothesis. Transplantation has to be between 6 an 24 Month before participation. | Dietary Supplement: 500ml water intake<br>* subjects have to ingest 500ml water within 5 minutes after resting 30 minutes in supine position<br>|
| Active Comparator: kidney transplanted patients<br>Control group, age, gender and medication matched. Transplantation has to be between 6 an 24 Month before participation. | Dietary Supplement: 500ml water intake<br>* subjects have to ingest 500ml water within 5 minutes after resting 30 minutes in supine position<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| norepinephrine plasma level |  | 30-40 minutes after water drinking | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pressure response | cardiovascular changes are monitored by finapress and ICG | blood pressure 30-40 minutes after water drinking | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Water drinking, osmoreceptors, autonomic failure, syncope, blood pressure, liver transplant