Radiation sickness normally starts to take effect within 24 hours of exposure to high levels of ionizing radiation, the type capable of exerting immediate chemical effects on the body. DNA becomes damaged and cells are destroyed in various tissues, but one of the main areas affected is the gut. Now, researchers claim to have developed a drug which can stop this intestinal damage after the exposure has occurred.
“Because radiation-induced damage to the intestines plays such a key role in how well a person recovers from radiation exposure, it's crucial to develop novel medications capable of preventing gastrointestinal damage,” explained Darrell Carney, from the University of Texas Medical Branch. This led the team to produce a single injection that, when given 24 hours after exposure to radiation, significantly increased the survival rate of mice. The team's findings were published in the journal Laboratory Investigation.
When the gastrointestinal tract is subjected to high doses of radiation, it’s affected in a number of different ways. Primarily, the ionizing radiation – such as gamma rays or X-rays – causes the breakdown of the intestinal lining, more specifically damaging the crypt stem cells that continuously grow, divide, and replace the cells lining the inside of the gut. This impacts the intestines' ability to absorb food and water, one of the main reasons why those suffering radiation sickness become so dehydrated. Damaging the lining has another effect too, allowing the bacteria that normally inhabit the gut to infect the body.
The new treatment is a peptide drug called TP508 and has been used previously to stimulate the repair of skin and tissue, especially in patients with Type 2 Diabetes, who are at risk of losing their limbs. The researchers found that injecting this drug into mice 24 hours after exposure to radiation stimulated their intestines to begin tissue repair.
This isn’t, however, the first drug to be developed to attempt to trigger cell growth in the gut of mice, and another has been developed to protect blood-forming stem cells. Even though none of these drugs cure radiation sickness, they could give those exposed crucial time to seek further treatment.
“The current results suggest that the peptide may be an effective emergency nuclear countermeasure that could be delivered within 24 hours after exposure to increase survival and delay mortality,” said Carla Kantara, lead author of the study, “giving victims time to reach facilities for advanced medical treatment.”