The Role of L-arginine in the Endothelial Dysfunction

NCT00583388 | Withdrawn DMC

• 1 other identifier: 06-008907
• Study Type: observational
• Target: N/A
• Locations: 0 countries
• Sites: N/A

Brief Summary

Acute cardiac and vascular events, like heart attack and sudden cardiac death manifest a clear surge in the early morning hours around the time of waking, so that their peak onset is between 6AM and 11AM. The mechanisms are not fully understood, but we had shown that healthy subjects have impaired vascular reactivity in the early morning (endothelial dysfunction). This is associated with a decrease in nitric oxide levels (a substance that promotes vasodilatation). We also have described that vessel reactivity and the levels of this substance can recover by noon only when people breakfast. L-arginine is a semi-essential amino acid found in large quantities in chicken, in fish, and beans and is the substrate for the production of nitric oxide Therefore we want to test if there is a beneficial effect of administration of L-arginine on the circadian pattern of vessel reactivity. Our goal is to understand why cardiovascular events are more likely to happen in the early morning and how to prevent. The research will help us to understand the efficacy, acute effects and tolerability of high doses of L-arginine. This can lead to future research to assess long term effects of L-arginine supplements to prevent cardiovascular events in the early morning hours.

Conditions

Healthy

Keywords

cardiology; preventive medicine; cardiovascular physiology; healthy subjects

Study Arms (1)

A

42 healthy subjects aged 18 to 60 will be be randomly assigned to 6 different treatment sequences.

Dietary Supplement: L-arginine; Device: Ultrasound

Interventions

L-arginine DIETARY_SUPPLEMENT

Each subject will be exposed to three treatments, a) 5 g of L-arginine, b) 15 g of L-arginine, and c) placebo, the sequences will be randomly assigned to the 42 volunteers. The washout period between interventions will be from one to two days.L-arginine will be mixed in 60 cc of dextrose-based syrup to blind the taste and color of the L-arginine powder.

A

Ultrasound DEVICE

Ultrasound from the brachial artery will be done on 3 occasions: at 9 pm after 4hs of fasting, at 6 am and at 11 am. The brachial artery images will be acquired above the antecubital fossa in the longitudinal plane of the artery with an ultrasound machine using a 6-MHz linear transducer. Flow-mediated vasodilatation will be assessed by the reactive hyperemia method (inflation of a blood pressure cuff around the forearm to 200 mmHg for 5 minutes and then released). The diameter of the brachial artery will be assessed 60 to 90 s after deflation of the cuff. After a 10min period a second baseline image of the brachial artery will be obtained. Non-low-mediated vasodilatation will be measured by an administration of a sublingual dose of nitroglycerin (0.4 mg).

A

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

community sample

You may qualify if:

• healthy subjects

You may not qualify if:

• renal disease; liver disease, sleep disorders, smokers, using chronic medications

Sponsors & Collaborators

• Mayo Clinic: lead

Biospecimen

Retention: SAMPLES WITHOUT DNA

whole blood

MeSH Terms

Interventions

Arginine; Ultrasonography

Intervention Hierarchy (Ancestors)

Amino Acids, Basic; Amino Acids; Amino Acids, Peptides, and Proteins; Amino Acids, Diamino; Amino Acids, Essential; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis

Study Officials

• Virend K Somers, MD, PhD

  Mayo Clinic

  STUDY CHAIR

Study Design

• Study Type: observational
• Observational Model: CASE CROSSOVER
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: December 20, 2007
• First Posted: December 31, 2007
• Study Start: June 1, 2010
• Primary Completion: June 1, 2010
• Study Completion: June 1, 2010
• Last Updated: April 28, 2015

Record last verified: 2015-04