In a world-first, an ‘Aussie-as-they-come’ study will explore the potential of spider venom to revolutionise heart transplants.
Dr Sarah Scheuer (pictured) has received an Avant Doctor in Training Research Scholarship to help fund her study. Chair of the Avant Foundation Board, Dr Penny Browne, said Avant is excited to be empowering tomorrow's medical researchers, “We can’t wait to see what the results are for this life-changing technology. It’s really what Avant’s Doctor in Training Grant program is all about, changing the lives of researchers and patients alike.”
Getting hooked on cardiothoracics
Originally interested in paediatrics, it was a Tetralogy of Fallot repair Dr Scheuer witnessed during her elective observing a cardiac surgery mission in Kenya that sparked her interest in cardiothoracic surgery. Later she joined the Cardiothoracic Department at St Vincent’s Hospital, Sydney, as an intern, and was well and truly hooked. “I had an absolute blast in the cardiothoracic unit at Vinnies and now can’t fathom doing anything else”.
That was in 2013. Since then, Dr Scheuer completed her internship and residency, and is currently working as a surgical registrar and cardiothoracic research fellow. Passionate about what’s happening at the cutting-edge of medicine, Scheuer has embarked on a PhD, under the supervision of Professor Peter Macdonald. She will investigate the cardio-protective effects on donor hearts of a novel peptide extracted from spider venom, particularly those retrieved via a donation after circulatory death (DCD) pathway.
A study as Aussie as they come
“You couldn’t get a more-Australian study”, Dr Scheuer laughs, praising the research network that kick-started it. “We were contacted by a team in Queensland saying they had identified a novel agent with the potential to protect against ischaemia and suggested we try it in hearts.”
The team at the University of Queensland has been testing a range of venoms to identify peptides with therapeutic application and had success in identifying peptides with potential in animal models of several diseases including pain and epilepsy. Dr Scheuer said the first step was to have the Queensland team send a small amount of the new peptide to their lab in Sydney, noting, “Just because it works in the in-vitro assays, by no means does that mean it’s going to work in the heart.”
The added novelty of this study is, “It’s not just the peptide itself, but we’re demonstrating an effect via a channel that no one has ever thought was significant in the heart,” she explained.
Impact on transplants, the donor pool and waitlists
This study could open up a whole new avenue of potential hearts for transplant.
“One of the big problems is the amount of time patients have to wait. Sometimes by the time a transplant comes up, they’re severely weak and de-conditioned. This study will have the flow-on effect of shortening donor wait-times while also increasing the number of usable hearts”, enthuses Dr Scheuer.
The groundbreaking work performed at the Victor Chang Cardiac Research Institute and St Vincent’s Hospital has already made great gains in this area, “Previous research done in this lab led to us start doing transplants in 2014 using hearts donated via a DCD pathway. However, these hearts are exposed to potentially damaging warm ischaemia, which hearts donated via the traditional pathway don’t experience. To counteract this, we give the heart a preservation flush containing supplements. These are supplements we know protect the heart and help it recover, even after ischaemia,” Dr Scheuer said.
She describes the process, “We remove the heart from the donor, flush it with the supplemented solution and put it onto a device called the TransMedics rig which circulates and oxygenates blood via a pump, restarting the heart. This protects the heart from further damage, but also allows us to assess it and make sure it is okay to use.”
Dr Scheuer explained that in order to use a DCD donor heart, the patient needs to progress to circulatory death within 30 minutes of withdrawal of life support, a very narrow window. “There is a variable period of time between when life support is withdrawn and the patient passes away, exposing the heart to ischaemia,” she said. “At this stage, a heart can only tolerate up to a 30-minute warm ischaemic time, even with the current supplementation. What we’re trying to do with my work using this new agent is to push this time out. We think if we could increase that time out to more like 60 minutes it would have a significant impact on the number of donors we could potentially use.”
Dr Scheuer will test her hypotheses for the study on various models of transplantation, utilising a preservation flush containing the spider venom peptide.
Wider implications for the new peptide
Dr Scheuer is excited about the potential, “If we’ve got this agent that’s really protective against both cardiac and neurological ischaemia, we could have this formulated into something that could be given in an ambulance, for example in an out-of-hospital arrest situation – it could be the ‘Epi-Pen’ of cardiac arrest”.
The findings will be available in late 2019.
2019 Avant Doctor in Training Research Scholarship Program
This year’s program will provide up to $450,000 in research funding for 19 full-time and part-time scholarships and grants for short-term projects. Applications open at 12 pm (AEDST) on 4 February 2019 and close at 5 pm (AEST) on 31 May 2019. For more information, visit the Avant Doctor in Training Research Scholarship Program website.