The immunohistochemical profile of the myelomeningocele placode: is the placode normal?

One key to predicting optimal outcome of novel treatments, such as fetal surgery, for myelomeningocele is understanding the structure of the placode. We hypothesize that if the placode retains normal patterning and is simply unneurulated, then repair may be effective in preventing secondary injury. Serial sections of human myelomeningocele placodes were characterized using novel immunohistochemical caudal spinal cord markers (H4C4, AC4, NOT, VIN-IS-53, and FP3) and established structural markers (e.g. neurofilament, glial fibrillary acidic protein, or synaptophysin). The myelomeningocele placodes studied exhibited abnormal patterning along the dorsoventral and rostrocaudal axes indicative of a change in pattern determination and a paucity of maturing neurons. In addition, there was significant inflammatory infiltrate, gliosis and fibrosis consistent with secondary injury. Additionally, injury to the placode was also demonstrated. The combination of effects may be contributory to abnormal spinal cord function in myelomeningocele patients.