Using the relaxin hormone to treat Asthma – an intriguing possibility

A modified form of the Relaxin hormone developed by Florey scientists appears to be safe, cheap to manufacture and has significant anti-fibrotic capabilities, which could have major implications for treating fibrotic diseases like asthma and heart disease.

Relaxin is the hormone that aids women to give birth – produced by the ovaries during pregnancy it ensures that the pelvic ligaments soften, for a brief time, long enough to push the baby out.

Key to this process is Relaxin’s ability to break down collagen, which is also the main characteristic of scar tissue or fibrosis. Fibrosis-related diseases account for up to 45 per cent of deaths globally, with fibrotic scaring present in everything from thickened arteries in heart disease to damaged lung walls in asthma.

While there are some therapies available that counter the build-up of fibrosis, they only delay disease progression. What is needed is a drug that can safely and cheaply reverse the scar tissue build-up in these diseases.

Today on World Asthma Day – when it is estimated that 334 million people globally have the disease – a group of Melbourne scientists may have found a drug that can reverse the damage caused by asthma.

Scientists have long believed Relaxin could be a way to reverse those diseases that are caused by the build-up of collagen – acting on , say, scarred heart tissue in the same way it does in the pelvic muscle of women about to give birth.

While clinical trials are currently underway internationally into using a recombinant drug-based form of the Relaxin hormone to treat patients with acute heart failure, there are concerns over the synthetic hormone being used, which is expensive and laborious to produce, as it has a two-chain structure like insulin.

A collaboration of researchers has developed and evaluated a single-chained form of Relaxin that eliminates all these concerns being cheap to produce and safe. The single-chain Relaxin, currently under a provisional patent application, was produced by Dr Akhter Hossain, Head of the Insulin Peptide Laboratory at the Florey Institute of Neuroscience and Mental Health, and then further characterised by scientists from Monash University’s Biomedicine Discovery Institute and the Monash Institute for Pharmaceutical Sciences.

The discovery of this “new type” of Relaxin is a major breakthrough in the potential treatment of fibrosis (scar tissue) related disease.

The modified Relaxin hormone was tested in animal models of heart failure and asthma. The researchers found that administering the new hormone intranasally to animals with chronic allergic airways disease (equivalent to asthma in humans) completely reversed established disease after nine weeks of onset. In addition the scientists showed that the modified Relaxin had selected activity unlike “normal” Relaxin, and was more easily modified to improve its drug-inducing effects.

The full paper is available to read in Chemical Science.