Bats Helping Humans: Medical Advances

By Shannon Currie

We all know that bats play and important role in the ecosystem, eating masses of insect pests and helping to pollinate many plants. More recently, scientists have discovered how understanding bat biology, in particular their physiology or how their bodies work, may help human medical research.

Vampire Bats have had some bad publicity over the years. They have been portrayed as scary and vicious animals seeking to suck the blood of unsuspecting people. This is certainly not the case with the majority of vampire bats feeding on large mammals such as cows and other livestock. Interestingly, it is in the mouths of these tiny mammals that scientists have found a powerful drug for the treatment of blood clotting diseases. The saliva of a vampire bat contains a special thrombolytic or clot busting protein that targets the netting in blood clots and quickly breaks them down. When a vampire bat bites its prey this enzyme goes to work, ensuring that their preys blood continues to flow and enabling the bat to feed until it is satisfied. This plasminogen activating protein has been synthesised and the resulting drug is called desmoteplase or DSPA after the scientific name for the common vampire bat Desmodus rotundus.

The most common health risk associated with blood clots are thromboemboli. A thromboembolism occurs when blood clots form in the body and break loose, travelling through the blood stream and resulting in the blockage of another blood vessel. These clots may block important blood vessels in the lungs (pulmonary embolism) and brain (stroke) and can result in death. Strokes are the number three killer in the United States and are considered the leading cause of long-term disabilities. Over the last 10 years important trials have been conducted utilising desmoteplase as a treatment for pulmonary emboli and stroke. Initial trials have shown that the drug works much more quickly and effectively at breaking up pulmonary blood clots than traditional treatments. Thanks to increasing research into bat biology and medicine you too may one day be saved by the bite of a vampire bat.

Another aspect of bat biology that may prove interesting and effective in medical research is the incredible ability of bat hearts to function at extremely low body temperatures. Humans are incapable of surviving a body temperature below 20°C (68°F). Amazingly, bats hearts can continue to function at temperatures approaching 0°C (32°F). When body temperatures are low the oxygen requirements of tissues are greatly reduced, and the body can survive little or no blood flow to the extremities for longer than at normal temperatures. Most bat species use this trick to reduce energy requirements through a process called torpor and drop their body temperatures on a daily basis. Since the 1950s surgeons have also used this fact to help them during open heart surgery by inducing surgical hypothermia. Unfortunately there are still major risks associated with surgical hypothermia such as reperfusion injury and brain damage. Understanding how the heart of a bat functions at low temperatures is still a mystery. It is thought that special receptors in the myocardial tissue of hibernators may be activated by certain chemicals during body cooling. These receptors are also present in humans and we may one day be capable of producing a drug that enables human hearts to stay functional at lower temperatures during surgery, reducing possible risk factors and reperfusion injury.

© 2012 Organization for Bat Conservation