Evaluation of the Effects of Urotensin-II and Soluble Epoxide Hydrolase Inhibitors on Skin Microvessel Tone in Patients With Heart Failure, and in Healthy Volunteers

Urotensin II (U-II) is newly discovered protein that may play an important role in human health and disease. U-II has been found to be a potent vasoconstrictor (narrower of blood vessels) which therefore may be involved in important diseases such as chronic heart failure - CHF (weak heart muscle disease). Many vasoconstrictors have been found to have effects on key organs such as the heart. Preliminary data by our group have demonstrated this is true of U-II. Recent evidence shows that in CHF, U-II levels in the blood are increased. The proposed study seek to determine the effect of blocking a possible downstream mediator of U-II on blood vessels by administration of soluble epoxide hydrolase inhibitor (sEHI). There will be 2 study groups 1) Healthy volunteers and, 2) CHF patients. Each arm of the study will run independently and will require 16 participants each (16 normal subjects and 16 CHF subjects). Participants will be screened to ensure that they are eligible. CHF patients will be required to withdraw from their CHF medication 24 hours prior to the study day (except for diuretics). On the study day, sEHI will be administered on the skin of participants in 3 asceding dosages. The technique to be used is iontophoresis. This is a non invasive technique in which a small amount of the compound is placed on the skin of the forearm. The drug is delivered across the skin by passing a small electric current over the area. The change in blood flow is then measured and analysed. We will also administer U-II agonist, noradrenaline, and distilled water (all via iontophoresis). Noradrenaline will be used a positive constrictor control. Change in blood flow will be assessed by Laser Doppler Velocimetry. If it is found that the sEHI is able to prevent blood vessel constriction in CHF patients, then it may represent a major therapeutic advance in the management of CHF.