An antibody to RGMa promotes regeneration of cochlear synapses after noise exposure.

Auditory neuropathy is caused by the loss of afferent input to the brainstem via the components of the neural pathway comprising inner hair cells and the first order neurons of the spiral ganglion. Recent work has identified the synapse between cochlear primary afferent neurons and sensory hair cells as a particularly vulnerable component of this pathway. Loss of these synapses due to noise exposure or aging results in the pathology identified as hidden hearing loss, an initial stage of cochlear dysfunction that goes undetected in standard hearing tests. We show here that repulsive axonal guidance molecule a (RGMa) acts to prevent regrowth and synaptogenesis of peripheral auditory nerve fibers with inner hair cells. Treatment of noise-exposed animals with an anti-RGMa blocking antibody regenerated inner hair cell synapses and resulted in recovery of wave-I amplitude of the auditory brainstem response, indicating effective reversal of synaptopathy.

Skeletal and soft tissue changes and stability in cleft lip and palate patients after distraction osteogenesis using a new intraoral maxillary device.

BACKGROUND: The authors have recently reported on the use of an internal maxillary distraction device. In this study, we report on the hard and soft tissue movements achieved with this intraoral distraction device, and the stability changes after distraction osteogenesis for maxillary hypoplasia in patients with cleft lip and palate. METHODS: Ten male patients with severe hypoplasia of the maxilla, with complete uni- or bilateral cleft lip and palate were included. The mean age of the patients at the time of operation was 11.91 years (±3.41). To evaluate the distraction process and stability, superimpositions on the preoperative lateral cephalograms were performed. The mean follow-up (FU) was 15.42 months (±3.94). RESULTS: Cephalometric measurements at all of the maxillary hard and soft tissue points improved significantly. Maxillary point A was advanced by 8.25 mm (±3.17; P < 0.001). After distraction soft tissue point A' had advanced 7.10 mm (±2.69; P < 0.001). The soft tissue to hard tissue ratio at point A was 0.86:1 after distraction. Maxillary horizontal relapse at point A was 14.1% at FU. Vertical relapse was not significant. CONCLUSION: This rigid intraoral distraction device can be successfully used in the correction of severe maxillary hypoplasia. The marked aesthetic improvement and low psychological encumbrance make this device viable for the treatment of cleft-related hypoplasia of the maxilla.