Early life inflammation is associated with spinal cord excitability and nociceptive sensitivity in human infants

Immune function and sensitivity to pain are closely related, but the association between early life inflammation and sensory nervous system development is poorly understood-especially in humans. Here, in term-born infants, we measure brain activity and reflex withdrawal activity (using EEG and EMG) and behavioural and physiological activity (using the PIPP-R score) to assess the impact of suspected early-onset neonatal infection on tactile- and noxious-evoked responses. We present evidence that neonatal inflammation (assessed by measuring C-reactive protein levels) is associated with increased spinal cord excitability and evoked brain activity following both tactile and noxious stimulation. There are early indications that this hyperalgesia could be maintained post-inflammation, supporting pre-clinical reports of early-life immune dysfunction influencing pain sensitivity in adults. More than 1 in 10 babies born in the UK are suspected of having an infection. Here the authors show that newborn babies with signs of infection (raised C-Reactive Protein levels) have exaggerated leg reflexes and pain-related brain activity following a heel prick blood test, suggesting they may be more sensitive to pain.

Automated summary

The relationship between immune function, pain sensitivity, and early life inflammation is not well understood in humans. This study found that neonatal inflammation is associated with increased spinal cord excitability and evoked brain activity following tactile and noxious stimulation. These findings suggest that hyperalgesia may persist post-inflammation, supporting previous research on immune dysfunction and pain sensitivity in adults.