Office of Technology Development (OTD)

Balaraman Kalyanaraman, PhD

There are currently several markers available for assessing the risk of vascular disease. For example, lipid markers are well established predictors of vascular disease. The most frequently measured lipid variables are total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides. Also, body mass index (BMI) is used as an indicator of risk of vascular disease, and elevated plasma levels of homocysteine are associated with an increased risk of developing occlusive vascular diseases.

Although lipid markers have been used for some time to predict risk, many papers have taken a position that lipids do not play the "key" role in predicting vascular disease risk. Additionally, body mass index shows a direct correlation with risk for vascular disease, but the measurements are usually not precise and do not apply to all patients. Elevated plasma levels of total homocysteine demonstrate a better predictor, but the measurement requires a 12-hour fast by the patient and expensive analytical techniques such as high-performance liquid chromatography (HPLC) and mass spectrometry. Furthermore, recent evidence indicates that endogenous homocysteine occurs in various forms and intermediates and that measurement of "total" homocysteine may be a more important measurement of chronic homocysteine levels. Currently there are no adequate immunoassay methods for measuring total homocysteine.

Dr. Kalyanaraman, Chairman and Professor of Biophysics at the Medical College of Wisconsin, Dr. Eric Ferguson, and Dr. Sampath Parthasarathy have developed antibody specific for homocysteine adducts. The antibody can be used to measure homocysteine adducts derived from total homocysteine in a rapid, cost effective manner in biological and non-biological samples.

The marketplace is dominated by the use of analytical techniques for measuring total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides. In addition, the demand for testing of homocysteine levels in patients who are at risk for atherosclerotic disease is growing explosively. These testing and reporting methods are entrenched to the point that many patients know the results of their tests and follow them across time.  Dr. Kalyanaraman and co-workers have developed a simple, cost-effective, non-enzymatic immunoassay for measuring total homocysteine levels.

This assay is amenable to standard immunoassay techniques such as ELISA and can be easily adapted to existing automated platforms for high throughput screening of patient samples.

Drs. Kalyanaraman, Ferguson, and Parthasarathy have made polyclonal antibody specific for homocystamide adducts and shown it effective in immunoassay in vitro. Further, his laboratory has used the antibody to evaluate the level of total homocysteine in a biological sample.