Clinical Research Directory

The Effects of Iontophoresed Vasoactive Drugs on Cutaneus Blood Flow

Sponsor: University Hospital, Linkoeping

Summary

Many acute and chronical medical conditions, such as, shock, sepsis, diabetes, hypertonia, and cardiovascular disease are associated with a perturbated or lost ability of regulating the diameter of the blood vessels. These changes in regulatory function can be seen especially in the smaller vessels in the body. It is therefore clinically relevant to develop investigation models that can detect and quantify such changes at an early stage. Historically, basic vascular function was investigated by mounting a section of a blood vessel on a tension sensor, submerging it in a temperature controlled and buffered solution to which vasoactive substances were added. This in vitro model has contributed substantially to our current knowledge of vascular pharmacology and function. However, using this method means that the vessel is removed from its natural environment and, hence no longer influenced by systemic or local mediators for controlling vessel diameter. The present study aims to investigate the local changes in blood flow and concentration of red blood cells of the superficial vessels in the skin of the forearm of healthy volunteers in response to various vasoactive substances. The purpose is to better understand how the regulation of diameter works in and to find a model that can give an early warning to when it does not function optimally. The vasoactive substances will be delivered through the skin to the vascular bed by a non-invasive method called iontophoresis. An electrode chamber containing a solution of the substance to be studied is placed on the subject's skin by double adhesive tape. The chamber comes with a transparent lid that prevents leakage and enables supervision of the effect on the underlying vasculature. When a voltage is applied the charged drug molecules begin to move through the skin and interact with the vessels. In the present study, a total electrical dose of 12 millicoulomb (mC) is going to be used (600 seconds x 0.02 milliampere). The effect of the applied drug is measured using two non-contact, optical measurement techniques. A better understanding of the pharmacology and regulation of blood vessels may lead to the developement of techniques that allow earlier detection of perturbations in vessel regulation and the onset of preventive medical treatment.

Official title: A Non-randomized Experimental Study of Optically Registered Pharmacodynamic Responses During Iontophoresis of Vasoactive Substances to the Skin of Healthy Volunteers

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