Transient expression of apolipoprotein-E in neonates with pontosubicular neuron necrosis.

An apolipoprotein-E (Apo-E) immunohistochemical study was performed on neonates with pontosubicular neuron necrosis (PSN), aged 38-42 weeks of gestation, and compared to findings for age-matched neonates without PSN. Apo-E was expressed in neurons in both the pontine nuclei and pyramidal layer of the hippocampus, as well as astrocytes of only the PSN cases. The immunoreactive neurons did not exhibit karyorrhexis and were found in neonates by the age of 6 days. Apo-E may be produced by astrocytes and taken up by neurons on membrane remodeling during early responses to cerebral hypoxic or ischemic insult in PSN neonates.