Heart failure occurs when the heart cannot keep up with its workload, causing symptoms such as shortness of breath, fatigue, swollen legs, and rapid heartbeat.
Biomedical experts believe that half of heart failure patients likely have low levels of the thyroid hormone T3 in their cardiac tissue.
While heart failure symptoms are commonly attributed to health conditions like coronary artery disease and high blood pressure, many studies suggest that low cardiac T3 may strongly contribute to a patient’s symptoms and underlying heart dysfunction.
In a new study, researchers have developed a new use for a common blood test, which could provide potentially life-saving treatment for heart failure.
The research was conducted by a team at the New York Institute of Technology College of Osteopathic Medicine (NYITCOM) and elsewhere.
In recent years, scientists have actively researched the connection between thyroid hormones and cardiac function.
Some clinical studies suggest that borderline-low thyroid hormone levels may increase the risk of death in heart failure patients, and animal studies indicating that restored cardiac thyroid levels can strongly improve heart function.
The symptoms of low cardiac T3 are also virtually indistinguishable from other conditions that lead to heart failure.
This suggests that a big number of underlying heart dysfunction and heart failure symptoms may actually be caused by a treatable T3 hormone imbalance.
Despite this treatability, clinicians are hesitant to prescribe T3 to heart patients, as too much of the hormone could accidentally trigger irregular heartbeat.
In addition, no method has yet been identified to titrate, or continually measure and adjust, for the dosage of T3 needed to safely restore the heart’s thyroid hormone function.
In the study, the team found an existing biomarker called brain natriuretic peptide (BNP) may provide the much-needed solution.
In medicine, biomarkers are biological molecules found in a patient’s blood, fluid, or tissue sample that can indicate whether a disease or condition is present.
They can also be used to see how well the body responds to treatments.
During heart failure, the heart will secrete higher levels of the biomarker BNP into blood, a key indication that the heart disease is worsening.
The researchers hypothesized that by analyzing a patient’s BNP levels in response to added T3, clinicians could find just the right dosage required.
Using rat models of heart failure caused by low T3 and heart attack, the researchers tested their theory, examining changes in BNP, cardiac function, and heart failure genes after T3 treatment.
For the first time, they discovered through a simple blood test, not an extensive, invasive procedure, that T3 could be adjusted to safely restore cardiac hormone balance.
In addition, because heart patients routinely undergo BNP and thyroid hormone testing, these widely used biomarkers could be easily monitored from blood tests.
The team says serum BNP levels can be used to titrate the volume of T3 required.
When T3 treatment led to a reduction in serum BNP levels, this was linked to improved cardiac function and reversal of these heart failure genes.
One author of the study is Martin Gerdes, Ph.D., chair and professor of biomedical sciences at NYITCOM.
The study is published in Frontiers in Physiology.
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