New drug may protect against deadly nuclear radiation

In a breakthrough, scientists have discovered a drug that may combat the deadly effects of nuclear radiation even after 24 hours of exposure.
A single injection of the investigative peptide drug TP508 given 24 hours after a potentially-lethal exposure to radiation significantly increased survival and delayed mortality in mice by counteracting damage to the gastrointestinal system.
The threat of a nuclear incident, with the potential to kill or injure thousands of people, has raised global awareness about the need for counter measures that can prevent radiation-induced bodily damage and keep people alive, even if given a day or more after contact with nuclear radiation.

Exposure to high doses of radiation triggers a number of potentially lethal effects.
Among the most severe of these effects is the gastrointestinal, or GI, toxicity syndrome that is caused by radiation-induced destruction of the intestinal lining.
This type of GI damage decreases the ability of the body to absorb water and causes electrolyte imbalances, bacterial infection, intestinal leakage, sepsis and death.

The GI toxicity syndrome is triggered by radiation-induced damage to crypt cells in the small intestines and colon that must continuously replenish in order for the GI tract to work properly.
Crypt cells are especially susceptible to radiation damage and serve as an indicator of whether someone will survive after total body radiation exposure.

"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 GI damage," said Darrell Carney, a professor at University of Texas Medical Branch (UTMB).
"The peptide drug TP508 was developed for use in stimulating repair of skin, bone and muscle tissues," said Carney, who is also the CEO of Chrysalis BioTherapeutics, Inc.
It has previously been shown to begin tissue repair by stimulating proper blood flow, reducing inflammation and reducing cell death.
In human clinical trials, the drug has been reported to increase healing of diabetic foot ulcers and wrist fractures with no drug-related adverse events.

"The current results suggest that the peptide may be an effective emergency nuclear counter-measure that could be delivered within 24 hours after exposure to increase survival and delay mortality, giving victims time to reach facilities for advanced medical treatment," said lead author Carla Kantara, a postdoctoral fellow from UTMB.
The study was published in the journal Laboratory Investigation.