A form of the killer gas carbon monoxide developed by UK scientists could help the recovery of heart attack victims.
The treatment might help heart attack patients
There is already evidence that carbon monoxide - one of the cocktail of gases produced by car exhausts - may have a beneficial effect on heart cells at low concentrations.
The chemical is made by many cells in the body and appears to have an important role.
However, it is difficult to get the carbon monoxide to the right areas at the right concentration - you cannot just breathe the gas, as it is poisonous.
Scientists from the University of Sheffield and the Northwick Park Institute for Medical Research in north London have developed a molecule which releases carbon monoxide at low concentrations.
They hope to harness that to help patients who have suffered heart attacks.
They believe that it could protect heart cells against lack of oxygen and other physical stresses suffered when a heart artery is blocked.
It is these which cause the death of heart cells after a heart attack, leading to long-lasting or even permanent damage.
In their tests, heart cells were grown in the laboratory then starved of oxygen for 24 hours.
Some were then left to "grow" naturally, while others were put in a chemical containing molecules that produced carbon monoxide - called CORM-3.
The cells doused in CORM-3 recovered more successfully than the others.
Similar experiments using animal hearts also showed the potential of the drug, and suggested that it might be able to prolong the life of organs for transplant.
Professor Brian Mann, one of the researchers involved in the project from the University of Sheffield, said: "CORM-3 shows real promise as a new drug to help heart disease, organ transplantation and as an anti-inflammatory drug.
"The potential therapeutic applications of CORMs are huge, considering the wide range of physiological activities of carbon monoxide seen in experimental models."
Another researcher, based at the Northwick Park Institute, Dr Robert Motterlini, said: "In the past carbon monoxide has been notoriously difficult to use therapeutically.
"In gas form it is difficult to target a specific area of the body to treat because carbon monoxide is toxic and damages cells when inhaled for long periods of time.
"CORMs will allow researchers to fully explore the biological function of carbon monoxide and its possibilities as a therapeutic agent."