Nerve growth factor levels rise following cardiopulmonary bypass in children: a novel mediator in the systemic inflammatory response syndrome?

Objectives

Nerve growth factor (NGF) plays a crucial role in the differentiation and survival of sympathetic neurones, including the ones represented in the cardiovascular system. NGF has also been reported to be an intermediary product in various inflammatory reactions. The aim of this study was to investigate whether cardiopulmonary bypass (CPB) has any effects on NGF release and to determine the time course of any changes in its release.

Methods

Twelve consecutive children undergoing elective cardiac surgery were recruited for the purposes of this study. The plasma levels of NGF, interleukin 6 (IL-6) and interleukin-8 (IL-8) were measured by enzyme-linked immunosorbent assay (ELISA). Samples were obtained from the patients at the following time points: induction of anaesthesia, end of CPB, and at 1, 2 and 24h following CPB.

Results

There was a highly significant increase in the release of NGF following CPB, reaching its highest concentration at 2 h following CPB. The pattern of release was very similar to that observed for IL-6 and IL-8. The results are summarised in the Table.

Table

Conclusions

NGF is released following CPB in paediatric patients, with a similar pattern to the one observed for known mediators of the systemic inflammatory response to CPB. Further studies, both in paediatric and adult patients, are needed to elucidate the role of NGF in the pathophysiology of the body response to CPB and to evaluate its clinical impact.