Our bodies work hard to keep everything in balance. Body temperature, fluid levels, and many chemical processes are carefully controlled so our organs can function properly.
When body temperature falls too low, this balance is disrupted. If a person’s core body temperature drops below 35°C (95°F) for a long period of time, a dangerous condition called hypothermia develops. The heart, brain, and other organs begin to work poorly, and without quick treatment, the condition can lead to unconsciousness or even death.
For many years, scientists have noticed something interesting about cooling the body. Lower body temperatures slow down the body’s energy needs. Because cells need less oxygen and fuel, they may be able to survive stressful situations better. Researchers have wondered whether this effect could be used to protect the brain after a stroke.
A new study suggests this idea may be possible. Scientists investigated whether two older medicines, chlorpromazine and promethazine, could safely create a cooling effect inside the body without using ice packs or cooling devices. Their findings were published in the journal Science Translational Medicine.
Stroke is one of the leading causes of death and long-term disability worldwide. The most common type is called an acute ischemic stroke. This happens when a blood clot blocks an artery that supplies blood to the brain. Without enough oxygen, brain cells begin to die within minutes.
Even when doctors successfully reopen the blocked blood vessel, damage can continue. The brain often experiences additional injury because of inflammation and other harmful changes that happen after blood flow returns.
As a result, many stroke survivors face long recoveries and may continue to struggle with speaking, walking, memory, or carrying out daily activities.
The research team wanted to find a way to protect the brain immediately after a stroke occurs. They tested a combination of chlorpromazine and promethazine, often shortened to C+P. The scientists hoped the drugs could place the body into a state that resembles hibernation, where energy use decreases and cells become more resistant to injury.
The researchers first studied mice. They temporarily blocked an artery in the animals’ brains to create stroke-like conditions and then gave them the drug combination. The team measured body temperature and monitored how much oxygen the animals were using.
The results were encouraging. The medicines lowered body temperature and slowed metabolism, meaning the body used less energy.
Unlike traditional cooling methods that often make animals shiver, the drug treatment lowered temperature without causing shivering. This is important because shivering actually increases energy use and can work against the benefits of cooling.
The treated mice developed smaller areas of brain damage and showed better recovery of neurological function after the stroke.
The researchers then moved to studies in rhesus monkeys, which are biologically more similar to humans. After creating stroke-like conditions, the scientists gave the animals the medicines through an intravenous infusion.
The treatment safely lowered the monkeys’ core body temperature to around 33 to 34 degrees Celsius. Their bodies also shifted to using fats and ketones for energy rather than relying mainly on glucose. Similar changes had been observed in the mice. Most importantly, the treated monkeys developed much smaller brain injuries than untreated animals.
Encouraged by these findings, the researchers conducted a small Phase I clinical trial involving 32 stroke patients. The participants were randomly assigned to receive either the drug combination or a placebo.
Different doses were tested, and doctors carefully monitored blood pressure, heart rate, breathing, and other vital signs. Patients were followed for three months after treatment.
The study found that the treatment was generally safe and well tolerated. There were no dangerous drops in blood pressure and no major breathing problems. Lower doses did not have much effect.
However, the highest dose, 100 milligrams, produced a mild reduction in body temperature and slowed the body’s metabolism. All of the patients who received this highest dose had good recovery after 90 days.
The findings are exciting because they suggest it may be possible to use medicines to temporarily slow the body’s energy needs and protect the brain after a stroke. If this approach works in larger studies, it could become an entirely new way of treating stroke patients.
At the same time, the results should be interpreted carefully. The human trial involved only 32 patients, which is far too small to prove that the treatment improves recovery for everyone. Larger clinical studies are still needed to confirm both safety and effectiveness.
Nevertheless, the research offers an intriguing new idea. Instead of simply restoring blood flow after a stroke, future treatments may also help place the brain into a protective, low-energy state that gives damaged cells a better chance to survive.
If you care about stroke, please read studies about how to eat to prevent stroke, and diets high in flavonoids could help reduce stroke risk.
For more health information, please see recent studies about how Mediterranean diet could protect your brain health, and wild blueberries can benefit your heart and brain.
Source: Science Translational Medicine study.
