Altered placental phenotype and increased risk of placental pathology in fetal spina bifida: a matched case-control study

Abstract

AbstractOpen spina bifida (SB) remains one of the most common congenital anomalies and associates with significant comorbidities in the fetus, which may, in part, be driven by placental maldevelopment. We hypothesised that placental pathologies and maldevelopment would be more prevalent in fetuses with SB compared to fetuses without congenital anomalies. Placental histopathology (H&E-stained slides) and transcriptome (Clariom D™ microarray) were evaluated for fetuses with isolated open SB undergoing either pregnancy terminations or term deliveries (cases; n=12) and control fetuses without congenital anomalies having term or preterm births (n=22). Associations between study group and placental histopathology were adjusted for fetal sex and gestational age [GA] at delivery. Relationships between placental histopathology and select placental gene expression signatures were also evaluated. Case placentae had lower placental weight than controls (median [IQR]: 263g [175, 370] vs. 455 [378, 560], p=0.001). Placental villi structural phenotype was different in cases, who had a higher proportion of immature intermediate villi than controls (32.5% [6.3, 56.3] vs. 10% [5, 13.8], p=0.01), but similar proportions of mature intermediate (10% [5, 10] vs. 10% [8.75, 11.25]) and terminal villi (22.5% [11.3, 43.8] vs. 30 [20, 36.3]), and similar odds of having many syncytial knots (adjusted odds ratio [aOR]=6 [0.2, 369]) as full-term born controls. Cellular phenotypic differences in case placentae included higher odds of having many Hofbauer cells (aOR=16.2 [1.4, 580], p=0.02) and a thick syncytial membrane (aOR=146 [3, 3.46e5], p=0.007). Expression in gene pathways related to immune/inflammatory processes, spinal cord injury, and Hedgehog and Wnt signaling were associated with placental maturity in cases. This study is the first to characterize placental histopathology in a contemporary cohort of fetuses with SB. Improved knowledge on placental histopathological and genetic phenotypes in spina bifida increases our understanding of mechanisms that may drive comorbidities to ultimately reduce offspring morbidity and mortality.