Cathepsin S Biomarker Linked to Cardiovascular Disease and Cancer Mortality
A biomarker (short for biological marker) is a feature or facet that can be used to measure the progress of disease or the effects of treatment. In medicine, biomarkers are often used to indicate the presence of a particular disease state, and testing for the substance can predict outcomes. Researchers have linked a known protein biomarker called cathepsin S to two very common disease states – heart disease and cancer – and may be used one day as a predictor of mortality.
Presenting at the European Society of Cardiology Congress, Elisabeth Jobs MSc of Uppsala University in Sweden investigated the association between blood levels of cathepsin S and the risk of mortality in a community-based sample of approximately 2,000 elderly men and women.
Cathepsin S is a cystein protease (enzyme) involved in the division of proteins, a process called proteolysis. High levels of the substance have been associated with increased inflammatory activity and previous studies have suggested that the substance is linked to heart disease by promoting atherosclerotic plaques. Cathepsin S activity is implicated in cancer through the stimulation of cancer cell migration and tumor angiogenesis.
Jobs and colleagues used data from two separate study groups – the Uppsala Longitudinal Study of Adult Men and the Prospective Investigation of the Vasculature in Uppsala Seniors. Cathepsin S was measured from serum samples. Despite controlling for factors such as age, systolic blood pressure, diabetes, body mass index, cholesterol, and smoking status, those with higher levels of serum cathepsin S were at a significantly increased risk for death – between 1.6 and 2 times greater than those with the lowest levels.
Using this information, it may be possible to develop a test which could serve as an early predictor of who may be at greatest risk of dying from cardiovascular disease or cancer. The findings may also lead to a new drug to reduce levels of cathepsin S in the blood to reduce the risk, similar to the way a statin lowers cholesterol to reduce cardiovascular risk. But there is still much unknown about the enzyme and exactly how it might contribute to either heart disease or cancer.
“Given its putative role in atherogenesis and tumorigenesis, cathepsin S has been put forward as a possible target of pharmaceutical intervention and the development of selective cathepsin S inhibitors is ongoing,” write the authors. “Some of these inhibitors are being evaluated in various phases of clinical trials. If these drugs are found to be effective, tools for identification of target groups and monitoring of treatment need to be developed.”
Jobs E, et al "Association between serum cathepsin S and mortality in older adults" JAMA 2011; DOI: 10.1001/jama.2011.1246.
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