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The Role of L-arginine in the Endothelial Dysfunction

NCT00583388 · Status: WITHDRAWN · Type: OBSERVATIONAL

Last updated 2015-04-28

No results posted yet for this study

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

Interventions

DIETARY_SUPPLEMENT

L-arginine

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.

DEVICE

Ultrasound

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).

Sponsors & Collaborators

Principal Investigators

  • Virend K Somers, MD, PhD · Mayo Clinic

Eligibility

Min Age
18 Years
Max Age
60 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2010-06-30
Primary Completion
2010-06-30
Completion
2010-06-30

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00583388 on ClinicalTrials.gov