Hypoxic-ischemic brain injury, which occurs when the brain's supply of oxygen and blood is blocked for some period of time, is the most common cause of death or disabilities in newborn babies. When brain cells are cut off from nutrients and blood, they can die, and that neuronal death leaves infants who have hypoxic-ischemic brain injury at greater risk of developing neurological diseases such as cerebral palsy. While it can help to cool the babies down after a hypoxic-ischemic brain injury, more treatments are needed to help infants that are recovering from the injury avoid further medical problems.
Previous studies have suggested that lactate might be useful in the treatment of brain injuries. While lactate may be acting through its receptor, which is called HCAR1, not much is known about the role HCAR1 may play in the brain.
In a study reported in eLife, researchers used a mouse model of cerebral hypoxia-ischemia to learn more. In mice engineered to lack the HCAR1 gene, tissue regeneration was impaired compared to normal mice in the hypoxia model. After a hypoxia injury, there was partial healing in the brain tissue of normal mice, and growth of new cells that could help repopulate parts of the brain that had been injured. But there was not much regeneration in the mice without HCAR1, the researchers explained.
More work will be needed to determine whether these effects are also seen in people, the scientists cautioned.
Lactate is well known for its role in exercise. When we perform strenuous activities, muscle cells generate lactic acid or a less acidic form of the chemical, lactate. But scientists are finding that it has broader importance.
"Experiments on mice indicate that injections of extra lactate can improve rehabilitation after a brain injury. But the reason for this has been unclear up until now," explained researcher and associate professor Johanne Egge Rinholm of the University of Oslo.
Cells can get energy from lactate, but recent work has indicated that lactate can act as a signaling molecule, added Rinholm. This study has shown that the lactate receptor may play a significant role in brain repair after a hypoxic-ischemic injury.