In the last few years, therapeutic hypothermia (the deliberate reduction of body temperature) has emerged as a possible treatment for ischaemic stroke (stroke caused by a blood clot). Hypothermia causes less blood to flow to the brain and decreases the body’s metabolic rate (the amount of energy it uses).
Hypothermia reduces or slows some of the harmful events that take place in the brain during and after a stroke, such as inflammatory responses and cell death. However, when body temperature drops below a certain level the body’s automatic response is to try to create heat itself (for example, by shivering).
The techniques that are currently used to cool patients in clinical trials cause them to shiver. This has the opposite effect to what was intended (cooling), and may have limited the success of hypothermia as a treatment for stroke in clinical trials to date.
Torpor is a natural state of reduced body temperature and metabolism (energy use).
However, in torpor the body does not try to produce its own heat. It occurs naturally in some animals in response to food shortage - hibernation is a well-known example of torpor.
Recent research has shown that certain drugs can trigger torpor, even in animals that don’t naturally go into this state. Researchers hope that we may be able to harness the protective effects of torpor to develop new treatments for ischaemic stroke.
However, several key questions still need answering before the effects of torpor can be used to develop new treatments for stroke. This research aims to answer these questions:
- How does torpor affect brain activity?
- How does torpor affect brain function?
- Does producing torpor using drugs protect the brain against damage caused by a stroke?
The researchers will use mice models to look at how torpor affects brain activity and function, and its effect on the amount of brain damage and disability that stroke causes.
It is hoped that this research will provide evidence of the effectiveness of torpor in slowing the damage caused by ischaemic stroke, and will be the first step in the development of new treatments for stroke patients.