David D. Limbrick, Ph.D. - US grants

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Proteomic analysis of cerebrospinal fluid (CSF) of human preterm infants has not previously been reported. Data derived from such analysis could provide critical information regarding conditions impacting neurodevelopment and play a key role in the identification of biomarkers of newborn neurological disorders such as post-hemorrhagic hydrocephalus.

DESCRIPTION (provided by applicant): The candidate for this Career Development Award (CDA) is a pediatric neurosurgeon with a specific interest in advancing the field of post-hemorrhagic hydrocephalus of prematurity (PHH) and improving the care and outcomes of infants with this condition. The rigorous career development program outlined in this proposal has both didactic components and mentored scientific training in the laboratories of Drs. Terrie Inder and David Holtzman at Washington University. The proposed program builds on the strengths of the University's NIH-supported interdisciplinary research centers and the Clinical Research Training Center to focus the candidate's training on clinical research methodologies, cerebrospinal fluid (CSF) protein biology, and neurodevelopment and disability in the preterm infant. The additional training and skills acquired through this CDA will complement the candidate's previous research background and provide new expertise necessary to become an independent clinician-scientist. The central hypotheses of this proposal are that CSF levels of the neurodevelopment proteins L1CAM and amyloid precursor protein (APP) are selectively increased in PHH, and that protracted elevations of these proteins are associated with increased ventricular size, ventriculoperitoneal (VP) shunt requirement, and adverse neurological outcome. The Specific Aims of this proposal are to: 1) compare the levels of CSF L1CAM and APP in control, PHH, and other neurological conditions; 2) define the association between CSF L1CAM and APP and ventricular size in PHH; and 3) determine the relationship of PHH-associated CSF L1CAM and APP elevations to neurodevelopment outcomes at 18-24 months corrected age. The candidate proposes to leverage his participation in the Hydrocephalus Clinical Research Network to establish a multi- institutional neonatal CSF repository at Washington University. CSF levels of L1CAM and APP in PHH will be measured using ELISAs and compared with those in intraventricular hemorrhage and other neurological conditions common to preterm infants. The association between these CSF proteins and ultrasound-based measures of ventricular size will defined, and the relative gains afforded by CSF L1CAM and APP in identifying infants that require VP shunts will be estimated. Finally, the relationship between CSF L1CAM and APP levels and neurodevelopment outcome will be determined using Bayley Scales of Infant Development-III scoring at 18-24 months corrected age. If successful, these studies will advance the field of PHH by providing crucial data for the development of CSF L1CAM and APP levels as markers of PHH-associated neurological disability. The most immediate benefit of these markers would be to complement existing image-based ventricular measures to better inform clinical trials directed at improving the outcomes of infants with PHH. PUBLIC HEALTH RELEVANCE: Post-hemorrhagic hydrocephalus (PHH) of prematurity is the most frequent cause of severe cognitive and motor disability in preterm infants. Despite its profound effects on neurological outcome, there has been relatively little research into optimizing the treatment of this condition. This project investigates new protein markers intended to provide physicians with important feedback in real time about the effectiveness of treatment in preventing long-term neurological disability.

Hydrocephalus primarily affects infants under one year of age. The traditional treatment for hydrocephalus is cerebrospinal fluid (CSF) shunt. Life-time complications of CSF shunts are high and expensive, with annual hospital charges of nearly $2.0 billion, accounting for 3.1% of all pediatric hospital charges. As shunt complications also adversely impact quality of life, it is not surprising that surveys of families affected by hydrocephalus show that they desperately desire shunt-free treatment options. The most promising shunt-free treatment for infant hydrocephalus is endoscopic third ventriculostomy with choroid plexus cauterization (ETV+CPC), which our Hydrocephalus Clinical Research Network (HCRN) and others have shown to be safe and viable. However, the cognitive outcome of ETV+CPC compared to shunt is not known. Our data suggest that most families would accept the risks of ETV+CPC for the chance to be free of shunt, but only if initial treatment with ETV+CPC will not lead to noticeable sacrifice in cognitive outcome compared to shunting. With this U01 proposal, we aim: 1. To determine, in infants ?12 months corrected age, with hydrocephalus requiring treatment at tertiary care pediatric neurosurgery centers in North America, does ETV+CPC compared to shunt result in non-inferior cognitive outcome at 12 months from surgery, as measured by Bayley Scales of Infant and Toddler Development (Bayley-III) Cognitive Scale with a non-inferiority margin of 1.5. 2a. To determine, in the same cohort, if ETV+CPC compared to shunt results in non-inferior Bayley-III Motor/Language Scales or Vineland-3 Scales. 2b. To compare other measures of treatment performance (brain/ventricle volume, treatment failure, hospital days, repeat surgery, use of imaging) and complications between treatment arms. 3a. To determine the effect of ETV+CPC and shunt on cerebral structural connectivity, with diffusion MR fractional anisotropy (FA) in the corpus callosum 12 months after surgery. 3b. To define the relationships between pre-operative brain/ventricular volume and cerebrospinal fluid (CSF) NCAM-1 level to post-operative corpus callosum FA and Bayley-III Cognitive Scale 12 months after surgery. 3c. To define the relationships between change in brain/ventricular volume (pre-operatively to 12 months post-operatively) to FA in the corpus callosum and corticospinal tract and Bayley-III Cognitive and Motor Scales 12 months post-operatively. To do this, we plan an RCT comparing ETV+CPC and shunt in infants with hydrocephalus, within the HCRN, a committed group of 14 leading North American pediatric neurosurgical centers with a long track-record of successful collaborative clinical research and RCTs in hydrocephalus. Optimal cognitive outcome, the primary concern of families, will therefore, be our primary outcome. Assessment of dMRI, a validated, non-invasive method of measuring white matter microstructural integrity and structural connectivity in the developing brain, will provide further insight into the developmental consequences of these 2 treatments. This RCT will help families determine the optimal treatment of hydrocephalus for their child.

Hydrocephalus (HC) is a common and debilitating neurological condition affecting up to 1 in 500 individuals. Ventriculoperitoneal shunting (VPS) has been the standard treatment for >60 years but shunts remain highly problematic, with an unacceptably high malfunction rate and often lead to a lifetime of complex neurosurgical care. Endoscopic third ventriculostomy (ETV) is an alternative to shunting but has limited efficacy in infants. Adding choroid plexus cauterization (CPC) to ETV seems to be a viable alternative to shunting infants. Despite conflicting outcomes, ETV-CPC is currently being offered routinely and globally, and with limited understanding of the risks or benefits of this procedure on brain development. The lack of knowledge about both the surgical and physiological consequences of ETV-CPC constitutes a significant barrier to broad acceptance of this procedure. Experimental studies are needed to determine the role of ETV and ETV-CPC in clinical practice, but the lack of appropriate, validated large animal models in which to test these techniques on brain physiology and, critically, on brain development, has never been studied. For example, the impact of ablating the choroid plexus, a major homeostatic organ which regulates neurogenesis and neurodevelopment, has yet to be determined. The NIH has responded to the unmet need for appropriate animal models by initiating Funding Opportunity PA-18- 623, ?Tools to Enhance the Study of Prenatal and Pediatric Hydrocephalus?, which promotes applications designed ?to transform the field of prenatal and/or pediatric hydrocephalus research by generating tools including animal?models?to understand disease mechanisms and/or developing therapeutics?. Our needs-based and hypothesis-driven proposal leverages our foundational work on ETV, ETV-CPC, and VPS to address the goals of PA-180-623 with 3 Specific Aims: (1) Develop a clinically-relevant, large animal model of HC to compare ETV, ETV-CPC, and VPS; (2) Define criteria for successful ETV, ETV-CPC, and VPS in the porcine model and determine the effects of these procedures on periventricular microstructure and hippocampal volume; and (3) Examine the effect of ETV, ETV-CPC, and VPS on cognitive function in piglets with infant HC. Pigs were chosen for this model both for their close homology to human neuroanatomy and physiology and the ability to use standard clinical neurosurgical techniques. Development of these novel treatment models of infant HC will fill a critical void in HC research and enable rigorous testing of emerging surgical procedures and injury mechanisms, which is essential to identifying best neurosurgical practices for the clinical management of HC. The goal of PA-18-623 will be achieved because this model will be freely shared and implemented by other investigators and educational programs.