Multifocal and Multiphasic Demyelinating Lesions After Radiation for Ependymoma in a Pediatric Population.

Radiation treatment is widely used to address unresectable intracranial tumors. Owing to the nature of therapy, healthy tissue and diseased regions will be affected. New insights have shown that not only does this impact brain parenchyma but it causes changes in fluid status, myelination, and the integrity of the blood-brain barrier. This alters how peripheral and central immune systems interact, perpetuating neuroinflammation. Rare case reports in the adult literature have described multifocal, multiphasic demyelinating lesions after radiation. Here we describe 2 pediatric cases of relapsing demyelination after and in conjunction with radiation therapy for ependymoma, consistent with a multiple sclerosis phenotype. Insights into the underpinnings of multiple sclerosis show peripheral inflammation, blood-brain barrier disruption, and antigenic mimicry stimulating neuroinflammation. Here we investigate the role that radiation, tumor burden, and systemic inflammation may play in creating demyelinating disorders. We strive to elucidate common pathophysiology between radiation-induced brain injury and multiple sclerosis.

Inchworming: a novel motor stereotypy in the BTBR T+ Itpr3tf/J mouse model of autism.

Autism Spectrum Disorder (ASD) is a behaviorally defined neurodevelopmental disorder characterized by decreased reciprocal social interaction, abnormal communication, and repetitive behaviors with restricted interest. As diagnosis is based on clinical criteria, any potentially relevant rodent models of this heterogeneous disorder should ideally recapitulate these diverse behavioral traits. The BTBR T+ Itpr3tf/J (BTBR) mouse is an established animal model of ASD, displaying repetitive behaviors such as increased grooming, as well as cognitive inflexibility. With respect to social interaction and interest, the juvenile play test has been employed in multiple rodent models of ASD. Here, we show that when BTBR mice are tested in a juvenile social interaction enclosure containing sawdust bedding, they display a repetitive synchronous digging motion. This repetitive motor behavior, referred to as "inchworming," was named because of the stereotypic nature of the movements exhibited by the mice while moving horizontally across the floor. Inchworming mice must use their fore- and hind-limbs in synchrony to displace the bedding, performing a minimum of one inward and one outward motion. Although both BTBR and C56BL/6J (B6) mice exhibit this behavior, BTBR mice demonstrate a significantly higher duration and frequency of inchworming and a decreased latency to initiate inchworming when placed in a bedded enclosure. We conclude that this newly described behavior provides a measure of a repetitive motor stereotypy that can be easily measured in animal models of ASD.