In a breakthrough for diagnostics, scientists have created an easy and effective test that identifies a heart failure biomarker in saliva, opening the door to more rapid and accessible life-saving medical interventions for the disease.
According to the Centers for Disease Control and Prevention (CDC), an estimated 6.7 million US adults have heart failure, and in 2023 the condition resulted in 14.6% of all deaths for the year. This rate of heart failure is mirrored in other countries including the UK and Australia. While there’s no cure, early intervention with changes to lifestyle and diet, plus medications, can mean the difference between maintaining quality of life and becoming a statistic. This makes diagnosis critical.
Now, scientists from the ARC Centre of Excellence in Synthetic Biology at Queensland University of Technology (QUT) have developed a novel and potentially groundbreaking saliva test that targets one particular protein biomarker, S100A7 – which could make early diagnosis and treatment a reality.
“Early symptoms are often subtle and non-specific, meaning patients typically receive treatment only in advanced disease stages,” said first author Dr Roxane Mutschler, from the ARC center at QUT.
Human psoriasin (S100A7) is a member of the S100 protein family and has already been implicated in a range of conditions including psoriasis and cancer. A team from Griffith University, led by Professor Chamindie Punyadeera, discovered S100A7, finding that it was also a biomarker for systolic heart failure. From that research, a large collaborative network of scientists then worked out a way to easily test for it in saliva, using an advanced laboratory technique known as mRNA display.
This method essentially employs proteins that stick really well to a specific target, such as a drug molecule or receptor. In this case, the target was S100A7 – a small calcium-binding protein that can appear at higher levels in saliva when someone has heart failure. The researchers wanted a reliable way to detect S100A7, so with mRNA display they were able to custom-build a small synthetic protein that would bind directly to it – like a key that fits a specific molecular lock – which could then alert scientists to its presence.
Not surprisingly, this innovative detection method has a lot of scope to target other disease biomarkers, too.
“It’s like changing the attachment on a power tool,” said Mutschler. “The basic system stays the same but you can adapt it to detect different health problems.”
Currently, heart failure is generally detected through a range of tests such as clinical evaluation, blood tests and imaging, which can be geographically and financially restrictive. Because of this, heart failure often goes undiagnosed until it becomes more advanced and more serious. Many of the early signs – shortness of breath during normal daily tasks, fatigue, weight gain and swelling in the legs and ankles – are non-specific symptoms, and people often attribute them to natural aging.
Interestingly, there’s been an uptick in research and development of diagnostic tools that use saliva as their foundation – something researchers attribute to COVID-19 testing. Healthy people generally have low levels of S100A7 in their saliva, while those with heart failure typically have twice as much.
In 31 patients with heart failure, the new saliva test identified it 81% of the time – which is on par with traditional, more invasive medical examinations. And it far outperformed current testing in identifying those who did not have heart failure (82% versus 52%), which can help rule out unnecessary treatment.
“The developed biosensor was able to quantify S100A7 in clinical samples and demonstrated >81 % correlation with the established ELISA assay using thirty saliva samples from patients with acute heart failure,” the researchers noted. “While our study was limited by a small patient cohort, these results provide a basis for further validation in larger populations.”
So while the study cohort was small, the results are hugely encouraging and now warrant broader testing populations. The researchers are also working on broadening the saliva test to detect a range of disease biomarkers, which could further reduce the resource and financial burden on patients and heath-care systems.
“This work contributes to the development of personalized healthcare by aiding people to detect signs and symptoms before the onset of a condition and to easily monitor its progression,” Mutschler added.
The research was published in the journal Biosensors and Bioelectronics: X.
