Pathogenesis of cerebral malformations in human fetuses with meningomyelocele

Olga A de Wit¹ , Wilfred FA den Dunnen² , Krystyne M Sollie³ , Rosa Iris Muñoz⁴ , Linda C Meiners⁵ , Oebele F Brouwer¹ , Esteban M Rodríguez⁴ and Deborah A Sival⁶

¹Department of Neurology, University Medical Center, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands

²Department of Pathology and Laboratory Medicine, University Medical Center, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands

³Department of Obstetrics and Gynecology, University Medical Center, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands

⁴Instituto de Anatomía, Histologíca y Patología Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile

⁵Department of Radiology, University Medical Center, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands

⁶Department of Pediatrics, University Medical Center, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands

author email corresponding author email

Cerebrospinal Fluid Research 2008, 5:4doi:10.1186/1743-8454-5-4


Published:	1 March 2008

Abstract

Background

Fetal spina bifida aperta (SBA) is characterized by a spinal meningomyelocele (MMC) and associated with cerebral pathology, such as hydrocephalus and Chiari II malformation. In various animal models, it has been suggested that a loss of ventricular lining (neuroepithelial/ependymal denudation) may trigger cerebral pathology. In fetuses with MMC, little is known about neuroepithelial/ependymal denudation and the initiating pathological events.

The objective of this study was to investigate whether neuroepithelial/ependymal denudation occurs in human fetuses and neonates with MMC, and if so, whether it is associated with the onset of hydrocephalus.

Methods

Seven fetuses and 1 neonate (16–40 week gestational age, GA) with MMC and 6 fetuses with normal cerebral development (22–41 week GA) were included in the study. Identification of fetal MMC and clinical surveillance of fetal head circumference and ventricular width was performed by ultrasound (US). After birth, MMC was confirmed by histology. We characterized hydrocephalus by increased head circumference in association with ventriculomegaly. The median time interval between fetal cerebral ultrasound and fixing tissue for histology was four days.

Results

At 16 weeks GA, we observed neuroepithelial/ependymal denudation in the aqueduct and telencephalon together with sub-cortical heterotopias in absence of hydrocephalus and/or Chiari II malformation. At 21–34 weeks GA, we observed concurrence of aqueductal neuroepithelial/ependymal denudation and progenitor cell loss with the Chiari II malformation, whereas hydrocephalus was absent. At 37–40 weeks GA, neuroepithelial/ependymal denudation coincided with Chiari II malformation and hydrocephalus. Sub-arachnoidal fibrosis at the convexity was absent in all fetuses but present in the neonate.

Conclusion

In fetal SBA, neuroepithelial/ependymal denudation in the telencephalon and the aqueduct can occur before Chiari II malformation and/or hydrocephalus. Since denuded areas cannot re-establish cell function, neuro-developmental consequences could induce permanent cerebral pathology.