Protocol Number: 05-H-0114

Title:

Evaluation of Systemic Nitrite Infusion and Its Effect on Exercise Physiology and Metabolism

Number:

05-H-0114

Summary:

This study will examine how nitrite infusions affect exercise tolerance (how much a person can exercise before having to stop). Exercise ability is limited by how fast oxygen can be delivered to the body and how fast the body can produce energy. Both of these processes are affected by nitric oxide (NO), a gas produced by cells that line blood vessels. NO is important in regulating blood vessel dilation, and consequently, blood flow. Nitrite may act as a storehouse for nitric oxide and be able to improve exercise tolerance.

Healthy normal volunteers between 21 and 45 years of age who can use an exercise bicycle may be eligible for this study. Candidates are screened with a medical history, physical examination, electrocardiogram, breathing tests, blood tests, and a pregnancy test for women who are able to bear children. Pregnant women are excluded from the study. The screening session includes practice exercise on the bicycle.

Participants exercise on a stationery exercise bicycle for about 30 minutes on each of two study days. During the test, they breathe in and out of a mouthpiece that allows inhaled and exhaled respiratory gases to be measured. Before subjects begin to exercise, a small tube is placed in the artery of their forearm inside the elbow. A longer tube called a central line is placed in a deeper vein in the neck after the area has been numbed. A thinner tube, called a pulmonary artery catheter, is placed through the central line and advanced into the chambers of the heart, through the heart valve, and into the lung artery. This catheter measures various pressures directly in the heart and lungs. Blood samples are drawn through the catheter also, to avoid the need for multiple needle sticks. Another tube is placed in the vein of the other arm to deliver medications.

Thirty minutes after all the tubes are placed, a blood sample is drawn for baseline measurements. Then, either saline (sterile salt water) or nitrite is injected into the tube in the arm vein. Thirty minutes after the injection, the subject starts exercising on the bicycle. The work setting on the bicycle is increased every minute, and the subject pedals until he or she is too tired to continue. During the test, a small blood sample is collected every 2 minutes. Heart rate, blood pressure, and heart rhythms are continuously monitored.

After the test on the first day, participants are admitted to the hospital to rest for the remainder of the afternoon and evening. The tubes are kept in place for the following morning, when the procedure is repeated exactly as before, except that subjects who received saline the first day are given nitrite the second day, and vice versa.

Sponsoring Institute:

National Heart, Lung and Blood Institute (NHLBI)

Recruitment Detail

Type: Completed Study; data analyses ongoing

Gender: Male & Female

Referral Letter Required: No

Population Exclusion(s): Children

Eligibility Criteria: This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Special Instructions:

Currently Not Provided

Keyword(s):

Cycle Ergometer

Exercise Physiology

Nitric Oxide

Sodium Nitrite

Healthy Volunteers

Recruitment Keyword(s):

Normal Volunteer

Healthy Volunteer

HV

Condition(s):

Healthy

Healthy Volunteer

HV

Investigational Drug(s):

Sodium Nitrite

Investigational Device(s):

None

Interventions:

Drug: Sodium Nitrite

Supporting Site:

National Heart, Lung and Blood Institute

Contact(s):

This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Citation(s):

Beckman JS, Koppenol WH. Nitric oxide, superoxide, and peroxynitrite: the good, the bad, and ugly. Am J Physiol. 1996 Nov;271(5 Pt 1):C1424-37.

Boucher JL, Moali C, Tenu JP. Nitric oxide biosynthesis, nitric oxide synthase inhibitors and arginase competition for L-arginine utilization. Cell Mol Life Sci. 1999 Jul;55(8-9):1015-28.

Furchgott RF, Zawadzki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980 Nov 27;288(5789):373-6.

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
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