[Changes of serum and cerebrospinal fluid insulin-like growth factor-II levels in neonates with hypoxic-ischemic encephalopathy].

OBJECTIVE

Many studies have demonstrated that low levels of insulin-like growth factor-I (IGF-I) may be associated with the hypoxic-ischemic brain damage (HIBD) and that IGF-I has a neuroprotective effect. The role of IGF-II, a structurally and functionally homologous polypeptide with IGF-I, is unclear in HIBD. This study was designed to observe the changes of serum and cerebrospinal fluid (CSF) IGF-II levels in neonates with hypoxic-ischemic encephalopathy (HIE) and to investigate its effects on HIE.

METHODS

Serum and CSF IGF-II levels in 41 neonates with HIE were measured by radioimmunoassay in the acute phase (postnatal age 12-24 hrs) and the convalescence phase (postnatal age 10-12 days). The 41 HIE neonates included 10 cases of mild, 12 moderate, and 19 severe HIE. Serum samples of 10 normal neonates were used as controls.

RESULTS

In the acute phase, serum IGF-II levels in the Mild HIE group (203.28 +/- 40.09 ng/mL) and the Moderate HIE group (192.33 +/- 39.66 ng/mL) were not significantly reduced, but were obviously reduced in the Severe HIE group (116.72 +/- 39.50 ng/mL) compared with normal controls (229.38 +/- 43.39 ng/mL) (P<0.01). During the convalescence phase, serum IGF-II levels in the Mild HIE group (285.53 +/- 49.44 ng/mL) and in the Moderate HIE group (278.69 +/- 51.34 ng/mL) increased significantly (P < 0.01); CSF IGF-II levels increased in the Mild HIE group from 27.23 +/- 7.82 ng/mL (acute phase) to 81.58 +/- 9.77 ng/mL (convalescence phase) (P < 0.01) and also increased in the Moderate HIE group from 23.43 +/- 7.79 ng/mL (acute phase) to 78.48 +/- 10.44 ng/mL (convalescence phase) (P < 0.01). The patients from the severe HIE group whose neurological symptoms or signs were improved in the convalescence showed higher serum and CSF IGF-II levels than in the acute phase (254.08 +/- 48.50 ng/mL vs 122.21 +/- 46.26 ng/mL; 69.42 +/- 10.20 ng/mL vs 15.05 +/- 7.03 ng/mL; P < 0.01). A positive correlation was found between the serum and CSF IGF-II levels in the HIE group (r=0.69, P < 0.01).

CONCLUSIONS

IGF-II levels in serum and CSF are associated with the pathogenesis and the prognosis of neonatal HIE.