Given 24 hours after potentially-lethal exposure to nuclear radiation, the drug appears to extend survival by lessening damage to the gut.
In the journal Laboratory Investigation, a team from the University of Texas Medical Branch (UTMB) at Galveston describes how the experimental drug TP508 showed promising results in tests on mice.
They note how a single injection of TP508, a regenerative peptide, significantly increased survival in mice after exposure to nuclear radiation, even though it was given 24 hours after the exposure occurred.
The drug works by limiting the damage to the gut, says lead author Dr. Carla Kantara, a researcher in biochemistry and molecular biology.
Exposure to high doses of radiation can kill because of various serious effects on the body. One of these effects is gastrointestinal (GI) toxicity syndrome, due to damage to the gut lining.
When the gut lining is damaged, its ability to absorb water during digestion is reduced, increasing the likelihood of imbalances in electrolytes, bacterial infection, leakage from the intestines, sepsis, and death, note the authors.
Senior author Darrell Carney, an adjunct professor in biochemistry and molecular biology, and also CEO of Chrysalis BioTherapeutics, Inc., a company that develops branded drugs like the one tested in the study, says:
"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."
Drug appears to activate stem cells and preserve crypt cell regeneration
GI toxicity syndrome results from radiation damage to the crypt cells in the small intestine and colon. These cells have to constantly replenish themselves to maintain the health and integrity of gut lining.
Crypt cells are very sensitive to radiation damage and their health is often used as an indicator of a patient's chances of survival following radiation exposure.
The study shows that TP508 appears to reduce the effects of GI toxicity by activating radiation-resistant stem cells and preserving the ability of crypt cells to regenerate themselves to maintain and restore the gut lining.
TP508 is a thrombin peptide developed to stimulate tissue repair following damage to skin, bone and muscle. Previous studies have shown that the drug works by stimulating growth of new blood vessels, restoring blood flow, curbing inflammation and reducing cell death.
Trials in human patients indicate that TP508 speeds up the healing of diabetic foot ulcers and wrist fractures with no serious drug-related side effects. Dr. Kantara concludes:
"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, giving victims time to reach facilities for advanced medical treatment."
The Centers for Disease Control and Prevention (CDC) distinguish between radioactive contamination and radiation exposure - both of which could occur if radioactive materials are released into the environment as the result of a nuclear accident, a natural event, or an act of terrorism.
Radioactive contamination is where radioactive material is deposited on or in an object or person. Radiation exposure occurs when radiation energy - in the form of waves or particles - from radioactive materials penetrate the body. A person exposed to radiation is not necessarily contaminated with radioactive material.
Radiation is all around us and our bodies have ways to deal with the low levels were are exposed to every day. Techniques like X-rays and CT scans use controlled amounts of radiation through the body to produce images. Exposure to small amounts of radiation over a long time can raise a person's risk of cancer. It can also cause mutations in genes that are passed on to offspring.
Exposure to a lot of radiation over a short period - such as from a nuclear accident - causes burns and severe damage to tissues and organs, which is the problem addressed by this study.
Meanwhile, Medical News Today recently learned from a series of articles published in The Lancet, that nowadays, people are more likely to suffer mental illness following a nuclear accident than experience physical effects.