Researchers have used heart and lung stem cells infected with the virus that causes COVID-19 to better understand how the disease impacts different organs, paving the way for more targeted treatments.

The research, co-led by Murdoch Children's Research Institute and the Peter Doherty Institute for Infection and Immunity (Doherty Institute) in Australia, found the responses to SARS-CoV-2 varied significantly depending on the cell type, allowing the team to identify effective antiviral drugs to treat infection in heart and lung cells.

To understand the impact of SARS-CoV-2 on different organs, the team engineered human stem cells in the lab into lung and heart cells and infected them with the virus.

The findings, published in the journal Stem Cell Reports, showed that the heart and lungs exhibit distinct antiviral and toxicity profiles that could inform better COVID therapies and treat its complications.

"Our findings highlight the importance of using several cell types for the evaluation of antiviral drugs to determine the best drug combinations for effective treatment of a virus that affects multiple organ systems," said David Elliott, Associate Professor at Murdoch Institute.

While SARS-CoV-2 primarily infected the respiratory tract, lung and cardiac complications occur in severe cases of COVID-19.

Cardiac complications are observed in up to 78 per cent of recovered COVID patients and ongoing myocardial inflammation in 60 per cent of patients.

"Although COVID-19 vaccines are highly effective in preventing severe illness and death, antiviral compounds are required for the treatment of COVID-19, particularly with the emergence of variant viruses that evade immunity," said Professor Kanta Subbarao, from the Doherty Institute.

"To date, only a handful of drugs have been approved for use in hospitalised COVID-19 patients and more are needed."

The study also looked at approved drugs for treating COVID, including Remdesivir and Molnupiravir, with some found to be more effective than others at treating infection in lung and heart stem cells.

It identified Alectinib and SPHINX31 as promising antivirals for SARS-CoV-2 in both heart and lung cells.

"We have provided valuable insights into virus-host interactions in tissues that are significantly affected in COVID-19, with implications that will further therapeutic options," Professor Subbarao said.