Introduction: Infants with intraventricular hemorrhage (IVH) are at risk for post hemorrhagic hydrocephalus (PHH) and poor outcomes. Iron has been implicated in cell death, brain injury, PHH and poor outcomes in animal models. We hypothesized differences in endogenous iron clearance markers or blood breakdown pathways in IVH influence development of PHH and neurodevelopmental outcomes.
Methods: CSF lumbar puncture (LP) samples were analyzed in premature infants with no IVH (n=11), Grades I-II IVH (n=4), Grades III-IV IVH (n=8) and PHH (n=11). Serial CSF ventricular taps (VT) in a subset of PHH neonates (n=8) were analyzed separately. Hemoglobin (Hb), transferrin, hemopexin, ceruloplasmin, ferritin, haptoglobin, non-protein bound iron, total bilirubin and hepcidin were analyzed using commercially available ELISAs. For neonates with VT samples, Bayley Scales of Infant Development, 3rd edition assessments were performed at age 2 years.
Results: LP Hb levels were increased in PHH infants compared to infants with no (p<0.0001), low-grade (p<0.001) and high-grade IVH (p<0.01). LP ferritin levels were increased in high-grade IVH (p<0.05) and PHH (p<0.01) compared to no IVH. There was a significant, positive correlation between LP ferritin and FOHR (p<0.001, r=0.45). No group differences were identified for other markers tested. There was a decrease in serial VT Hb and ferritin levels compared to initial measurements (Hb: p<0.05, r=-0.4; ferritin: p<0.05, r=-0.4). FOHR at time of initial VT was correlated with worse age 2 expressive (p<0.05, r=-0.8) and receptive (p<0.05, r=-0.8) language performance. VT hepcidin levels were correlated with worse age 2 cognitive performance (p<0.05, r=-0.8).
Conclusions: Early elevated LP Hb levels predicted development of PHH, while LP ferritin was elevated in neonates with IVH and PHH. In PHH, higher VT levels of hepcidin, a cellular iron export inhibitor, were associated with worse age 2 cognitive outcomes. These findings implicate Hb and hepcidin as key CSF predictors of PHH and outcome.
Patient Care: By recognizing a subset of infants with IVH who are at risk of developing PHH or having worse cognitive outcomes at age 2, neurosurgeons will be able to better select candidates for treatment. Subsequently, these surrogate markers may be useful to identify novel treatments of IVH.
Learning Objectives: 1. Readers will recognize elevated CSF hemoglobin levels after IVH as a potential predictor of PHH
2. Readers will recognize the association between increased ventricular hepcidin levels and worsened cognitive outcomes at age 2
3. Readers will understand the potential role for CSF levels of hepcidin and hemoglobin in predicting the clinical course of infants with PHH
References: 1. Chen Z, Chen Z, Gao C, et al (2011) Role of iron in brain injury after intraventricular hemorrhage. Stroke 42:465–470.
2. Gao C, Du H, Hua Y, et al (2014) Role of red blood cell lysis and iron in hydrocephalus after intraventricular hemorrhage. Journal of Cerebral Blood Flow & Metabolism 34:1070–1075.
3. Garton TP, He Y, Garton HJL, et al (2016) Hemoglobin-induced neuronal degeneration in the hippocampus after neonatal intraventricular hemorrhage. Brain Research 1635:86–94
4. Savman K, Nilsson UA, Blennow M, et al (2001) Non-protein-bound iron is elevated in cerebrospinal fluid from preterm infants with posthemorrhagic ventricular dilatation. Pediatr Res 49:208–212.