In babies, turning down inflammation soothes the hurt
PAINLESS This baby probably isn't crying because of nerve pain. New research reveals that infants and children don't feel nerve pain because their immune systems tamp down inflammation.
Laura Sanders is away on maternity leave.
Babies have it so easy.
I came to that conclusion after visiting Laura’s 4-month-old daughter, Baby Boo (she was born close enough to Halloween that I feel justified in using the nickname). Boo is the little sister of Baby V, who you’ve read about in this blog, and she’s a happy baby. And why wouldn’t she be? She has people seeing to her every need, playing silly games and making faces at her to keep her amused. I could do without the faces, but otherwise Boo has a pretty sweet deal.
My envy of Baby Boo and other babies rose to new heights when I came across a study in the Journal of Neuroscience that explains why babies and young children don’t feel nerve pain.
Researchers had already discovered that kids who haven’t reached puberty don’t get nerve ailments such as sciatica or phantom limb pain. Adults who lose a limb or slip a disc in their spine may feel this sort of pain right away. But infants and prepubescent children who have a limb amputated because of an accident or disease don’t develop phantom pain until years later.
In the new study, researchers used rats and mice to learn how youngsters fend off nerve pain. Nerve injury in adolescent and adult rodents caused inflammation and pain when the animals had to bear weight on the injured side or were exposed to heat or cold. But something else happened in infant mice: Their immune systems produced anti-inflammatory chemicals when nerves were injured, Rebecca McKelvey and Maria Fitzgerald of University College London and collaborators discovered.
Blocking these chemicals or injecting others that trigger inflammation caused baby mice to feel nerve pain, the team found. That finding suggests that babies’ pain sensors work just fine; it’s stopping the inflammation that normally keeps them from feeling pain. As the babies grew into adolescents, the inflammation-causing chemicals gradually overwhelmed the anti-inflammatory molecules that kept nerve pain at bay. Unfortunately, injecting anti-inflammatories into adult mice didn’t lessen their discomfort.
The researchers speculate that both mouse and human infants make anti-inflammatory chemicals so their bodies won’t reject friendly microbes. Reduced inflammation may also ease brain development by allowing immune cells in the brain to strip away damaged cells and snip dysfunctional connections between nerves. No nerve pain is just a side benefit.
I’ve been plagued with nerve pain similar to sciatica for a year now, experiencing pain that ranges from nuisance to excruciating. This study seems to suggest that tipping the immune response toward the anti-inflammatory side may eliminate nerve pain in adults like me. But that type of therapy is a long way off. I will just have to be content to know that Baby Boo won’t have to deal with this sort of discomfort for many years to come (and hopefully never). Of course, that won’t stop me coveting her anti-inflammatory superpowers.
