Oxidative Stress Markers In Inherited Homocystinuria And The Impact Of Taurine

Overview

Cystathionine beta-synthase deficiency is an inherited disease that results in elevation of a substance called homocysteine (Hcy) in blood and urine. Individuals with this disorder have a very high risk for developing blood clots and are at risk for developing eye and bone abnormalities. Current treatments are generally difficult to follow and can fail. Development of additional therapies has been limited by lack of understanding of how the disease works. The purpose of this study is to see if oxidative stress and inflammation are involved in the disease process and if short-term supplementation with taurine is an effective treatment. Funding source: FDA.

Cystathionine beta-synthase deficient homocystinuria(CBSDH) is an inherited disease that results in elevation of a substance called homocysteine(Hcy)in blood and urine. Individuals with this disorder have a very high risk for developing blood clots that can cause a stroke or other life-threatening problems. In addition, these individuals have bone and joint tissue abnormalities. Current treatment with an extremely strict diet and medication (betaine) is very difficult to follow, and often fails. Development of additional treatment strategies has been limited by a lack of knowledge and understanding of how this disease works. Hence, there is a need to better understand what causes the blood clots and the bone and joint tissue abnormalities. New data suggest that oxidative stress and inflammation play a central role in animals with this disease. Limited data on humans with this disease support this as well. Further, data from animals with this disease suggests that taurine, a natural body substance and food product, which is low in these patients, mitigates this effect. This study is designed to follow-up on these data. The purpose of the study is to increase our understanding of the disease process in this disorder, and to see in a pilot study if short-term supplementation with taurine is an effective intervention. The aims of the study are to: 1. see if substances (markers) associated with oxidative stress and inflammation are increased in individuals with CBSDH 2. see if the levels of these markers relate to the levels of homocysteine 3. see if the levels of these markers decrease with short-term taurine supplementation 4. see how bood vessels and platelets (small substances in the blood that help blood clot) work in individuals with CBSDH, if their ability to work is related to levels of markers of oxidative stress and inflammation, and if taurine supplementation improves how they work 5. see if alterations of bone strength are related to levels of markers of inflammation. The hypotheses to be investigated are as follows: * Biomarkers of oxidative stress and inflammation are increased in individuals with CBSDH * The degree of elevation of the biomarkers of oxidative stress and inflammation is relative to the degree of elevation of homocysteine, the main accumulating substance for this disease. * Treatment with taurine mitigates the elevation of biomarkers of oxidative stress and inflammation. * Endothelial function (blood vessel function) is abnormal in individuals with CBSDH even when receiving standard therapy and is improved with taurine supplementation. * Chronic platelet aggregation, a variable finding in individuals with CBSDH, is mitigated with taurine supplementation. * Decreased bone mineral density relates to the increase in inflammatory markers in CBSDH. In addition, baseline pharmacokinetics (how much taurine is in the blood) of oral pharmacologic doses of taurine will be developed.