Human Intestinal Amino Acid Absorption and the Role of a Local (Renin)-Angiotensin System (RAS)

Aim of this trial is to investigate the expression and localisation of different amino acid transporters and their regulatory proteins derived from the regulatory proteins of the local renin angiotensin system (RAS) in the intestine. This is investigated on one hand in patients who do not take any drugs interfering with RAS. On the other hand expression analysis is done in patients taking daily RAS-active drugs, like ACE inhibitors or sartanes.

After obtaining informed consent of patients attending the hospital for clarification of gastrointestinal symptoms by gastroduodenoscopy or colonoscopy, 2 biopsies (in addition to biopsies needed for clinical diagnostics) will be taken from each duodenum, jejunum, ileum and descending colon.

Biopsies are investigated anonymously at the Institute of Physiology of the University of Zurich. The mRNA content of amino acid transporters and regulatory proteins, respectively, in the biopsies is analyzed by quantitative PCR. Transport proteins are in addition analyzed with immunohistochemistry.

Furthermore amino acid concentration in plasma and urine samples are analyzed by HPLC. From plasma and serum samples RAS parameters like renin, aldosterone, ACE and angiotensin(1-7) are measured.

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Key information

Conditions

Healthy Participants Cardiovascular Diseases Hypertension Vascular Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

University Hospital Zurich, Gastroenterology and Hepatology

Zurich, Canton of Zurich, 8091, Switzerland

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Men and women aged 18-80 years
BMI 18-35 kg/m2
Group 1: patients taking daily RAS-active drugs, like ACE inhibitors or sartanes (treatment indication outside of this study)
Group 2: no therapy with RAS-active drugs, like ACE inhibitors or sartanes Gastroduodenoscopy and/or colonoscopy with a treatment indication outside of this study
Informed consent

Exclusion criteria

Severe pathologic alterations in the gastrointestinal tract (ulcers, tumors, celiac disease; GERD and gastritis are no exclusion criteria)
Status after operations of the gastrointestinal tract (except uncomplicated appendectomy or inguinal hernia repair)
Patients with malignant diseases
Severe acute or chronic diseases which require treatment (e.g. renal replacement therapy)
Patients with increased bleeding risk (e.g. oral anticoagulation, coagulopathy)
Drug or alcohol abuse
Mental disorders which limits the ability to fulfil all study requirements

Treatment and study plan

hypertension

Biological

patients taking daily ACE inhibitors or sartanes

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Registry information

Important dates

Study start: 2009
Study completion: 2011
First posted: Dec 3, 2010
Registry last updated: Nov 29, 2012

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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