0831 Postnatal infections and white matter injury in premature infants

The spectrum of white matter injury in preterm infants includes focal cystic necrotic lesions (periventricular leukomalacia - PVL) and diffuse myelination disturbance characterized by loss of premyelinating oligodendrocytes. Recent neuroimaging studies suggest that PVL incidence is declining while non-cystic injury remains a problem. It has been recognized for some time that hypoxia, ischaemia and maternal-foetal infections are associated with white matter injury. Emerging experimental data indicate that while pronounced ischaemia in the periventricular white matter is necessary, it alone is not sufficient to generate white matter injury, and reactive oxygen species, cytokines, glutamate and adenosine also have roles. The combination of ischaemia and inflammation appears to be particularly important. These two factors frequently coexist and amplify their effects leading to excitotoxicity and free radical attack. The premyelinating oligodendrocytes are intrinsically vulnerable to free radical attack due to immaturity of anti-oxidant enzyme systems and iron accumulation. Glutamate-receptor mediated injury leads to maturation-dependent cell death and loss of cellular processes. Recently-published work from the US and Canada shows that it is not only intrauterine infection that may be problematic in the genesis of progressive white matter injury but also recurrent postnatal infection.

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Pediatrics 2008; 122: 299-305
Arch Dis Child Fetal Neonatal Ed 2008; 93: F153-61
Ment Retard Dev Disabil Res Rev 2006; 12: 129-40