Background: Neurocognitive impairment among children born preterm may arise from complex interactions between genes and the intra-uterine environment.
Objectives: (1) To characterize the transcriptomic profiles of chorioamniotic membranes in preterm neonates with and without neurocognitive impairment via microarrays and (2) to determine if neonates with neurocognitive impairment can be identified at birth.
Materials/methods: A retrospective case-control study was conducted to examine the chorioamniotic transcriptome of gestational-age matched very preterm neonates with and without neurocognitive impairment at 18-24 months' corrected-age defined by a Bayley-III Cognitive Composite Score <80 (n = 14 each). Pathway analysis with down-weighting of overlapping genes (PADOG) was performed to identify KEGG pathways relevant to the phenotype. Select differentially expressed genes were profiled using qRT-PCR and a multi-gene disease prediction model was developed using linear discriminant analysis. The model's predictive performance was tested on a new set of cases and controls (n = 19 each).
Results: 1) 117 genes were differentially expressed among neonates with and without subsequent neurocognitive impairment (p<0.05 and fold change >1.5); 2) Gene ontology analysis indicated enrichment of 19 biological processes and 3 molecular functions; 3)PADOG identified 4 significantly perturbed KEGG pathways: oxidative phosphorylation, Parkinson's disease, Alzheimer's disease and Huntington's disease (q-value <0.1); 4) 48 of 90 selected differentially expressed genes were confirmed by qRT-PCR, including genes implicated in energy metabolism, neuronal signaling, vascular permeability and response to injury (e.g., up-regulation of SEPP1, APOE, DAB2, CD163, CXCL12, VWF; down-regulation of HAND1, OSR1)(p<0.05); and 5) a multi-gene model predicted 18-24 month neurocognitive impairment (using the ratios of OSR1/VWF and HAND1/VWF at birth) in a larger, independent set (sensitivity = 74%, at specificity = 83%).
Conclusions: Gene expression patterns in the chorioamniotic membranes link neurocognitive impairment in preterm infants to neurodegenerative disease pathways and might be used to predict neurocognitive impairment. Further prospective studies are needed.