Adrenomedullin increases in term asphyxiated newborns developing intraventricular hemorrhage

Objectives: Adrenomedullin (AM) is a newly discovered vasodilator peptide that participates in the regulation of cerebral blood flow. The aim of this study was to investigate whether circulating AM was increased in infants with prenatal asphyxia who developed intraventricular hemorrhage (IVH). Design and methods: A case-control study was performed on 40 full-term asphyxiated newborns: 20 developed IVH (group A) and 20 did not (group B). Forty term healthy newborns represented the control group. Biochemical laboratory parameters, neurological patterns, cerebral ultrasound scanning, and Doppler velocimetry were assessed at 12 and 72 h from birth. Plasma AM concentration was measured at 12 h from birth by means of a specific RIA. Results: AM levels were significantly higher in group A (20.2 ± 5.2 fmol/ml) than in group B (8.4 ± 2.1 fmol/ml) or controls (9.3 ± 2.6 fmol/ml). In asphyxiated newborns, AM concentration was correlated with middle cerebral artery PI value only in group B. Conclusions: Increased concentration of AM at 12 h from birth in asphyxiated newborns who later developed IVH suggests that this peptide may participate in the loss of cerebral vascular autoregulation in response to hypoxia and could be useful to discriminate, among newborns at risk, those with an adverse neurological outcome.