Death Risk May Double for Senior Citizens with Highest Level of Blood Biomarker
Protein biomarker cathepsin S may be related to cardiovascular disease and cancer
Aug. 30, 2011 Data from two studies of elderly men and women found those with high levels of the protein biomarker
cathepsin S in their blood had a much higher risk of death, according to a study in the Journal of the American Medical Association (JAMA)
In one study, the high level cathepsin people had double to risk of death compared to those with the lowest level.
This biomarker might have a relationship with the development of cardiovascular disease and cancer. The study is being
published early online to coincide with its presentation at the European Society of Cardiology Congress.
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Cathepsin S is a cysteine protease (a type of enzyme) involved in intracellular and extracellular proteolysis (division
of proteins by cellular enzymes). Higher circulating levels of cathepsin S have been shown to be associated with increased inflammatory
activity.
"Experimental studies suggest that cathepsin S activity is involved in the development of cardiovascular disease via
promotion of atherosclerotic plaques and destabilization of advanced plaques.
Moreover, cathepsin S activity has been implicated in the development of cancer via stimulation of cancer cell migration
and tumor angiogenesis," according to background information in the article.
Based on these previous reports, the authors hypothesized that circulating levels of cathepsin S would be a marker for an
increased mortality risk and launched their research. There had been a lack of prospective data regarding this potential association.
Elisabeth Jobs, M.Sc., of Uppsala University, Uppsala, Sweden, and colleagues investigated the association between serum
levels of cathepsin S and the risk of mortality in a community-based sample of elderly men and women.
The researchers used data from two independent community-based study groups:
● Uppsala Longitudinal Study of Adult Men (ULSAM), which included 1,009 men with an average age of 71 years. The
baseline period was from 1991to1995 and they were followed for up to 12.6 years, ending in 2006.
● Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) involved 987 people with an average age of
70 and 50 percent were women. The baseline period was 2001 to 2004 with a median follow-up of 7.9 years, ending in 2010.
Serum samples were used to measure cathepsin S.
In the ULSAM group, 413 participants died during follow-up. There were a total of 131 deaths due to cardiovascular
disease and 148 deaths due to cancer.
During follow-up with the PIVUS cohort, 100 participants died.
The researchers found that in multivariable models adjusted for age, systolic blood pressure, diabetes, smoking status,
body mass index, total cholesterol, high-density lipoprotein cholesterol, antihypertensive treatment, lipid-lowering treatment, and history of
cardiovascular disease, higher serum cathepsin S was associated with an increased risk for death.
In the PIVUS cohort, participants with the highest levels of serum cathepsin S had about double (200 percent) the risk of
death compared to participants with the lowest levels.
The authors also found that in the ULSAM cohort, participants with the highest levels of the biomarker had an
approximately 1.6 times (60 percent) increased risk for cardiovascular mortality, and an increased risk for death from cancer.
"Our community-based data confirm and extend previous experimental research that suggest that cathepsin S activity is
involved in the pathological processes leading to cardiovascular disease, cancer, and death," the researchers write.
"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.
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.
Our study suggests that it is possible to assess serum levels of cathepsin S in large populations. Future intervention
trials are needed to evaluate whether cathepsin S inhibition is a safe and effective pharmacological target for these diseases."
The authors add that "further research is needed to determine the utility of cathepsin S measurements in clinical
settings."
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Aug. 30, 2011 Data from two studies of elderly men and women found those with high levels of the protein biomarker
cathepsin S in their blood had a much higher risk of death, according to a study in the Journal of the American Medical Association (JAMA)
In one study, the high level cathepsin people had double to risk of death compared to those with the lowest level.