Researchers at Jefferson Medical College had discovered the existence of an enzyme in the blood that acts as a biomarker for conditions that lead to heart failures. Based on their findings they have now successfully developed a blood test to predict the onset of heart failure in patients with cardiac disease.
Scientists had previously showed that an enzyme called GRK2 or beta-adrenergic kinase (ßARK1) is critically important in heart function. It is increased in failing human hearts and contributes to the loss of the heart's contractile strength during the development of heart failure. Decreasing or inhibiting the enzyme reversed heart failure in laboratory tests.
In their latest findings, researchers have shown, using tissue samples from heart failure patients, that they could track heart levels of GRK2 in the blood.
The researchers reported their findings July 29 in an online article in advance of print in the European Heart Journal.
In the study, researchers had compared tissue samples from a group of 24 patients in heart failure who needed transplants to 58 patients who were not as sick, though had various stages of left ventricular malfunction. They found that the sicker patients had higher levels of GRK2 in the heart and in the blood.
Researchers feel that in future they would like to eventually perform large human trials to specifically look at levels of GRK2 to see if they can predict responses to drugs such as beta-blockers or other treatments for heart failure.
Researchers have known from animal studies that the expression of GRK2 appears to be regulated by hormones called catecholamines, which include norepinephrine and epinephrine, message-carrying neurotransmitters in the sympathetic nervous system.
In heart failure, the sympathetic nervous system is in overdrive, and levels of these hormones are high. In congestive heart failure, the beta-adrenergic receptor system fails to work properly. One of the functions of GRK2 or beta-adrenergic kinase (ßARK1) is to turn off beta-adrenergic receptors.