Diego M. Morales

Intraoperative magnetic resonance imaging to reduce the rate of early reoperation for lesion resection in pediatric neurosurgery

OBJECT This study describes the pediatric experience with a dual-multifunction-room IMRIS 1.5-T intraoperative magnetic resonance imaging (iMRI) suite and analyzes its impact on clinical variables associated with neurosurgical resection of intracranial lesions, including safety and efficacy. METHODS Since the inception of the iMRI-guided resection program in April 2008 at both Barnes-Jewish and St. Louis Childrens Hospital, a prospective database recorded the clinical variables associated with demographics and outcome with institutional review board approval. A similarly approved retrospective database was constructed from February 2006 to March 2010 for non-iMRI resections. These databases were retrospectively reviewed for clinical variables associated with resection of pediatric (age 20 months-21 years) intracranial lesions including brain tumors and focal cortical dysplasia. Patient demographics, operative time, estimated blood loss, additional resection, length of stay, pathology, and complications were analyzed. RESULTS The authors found that 42 iMRI-guided resections were performed, whereas 103 conventional resections had been performed without the iMRI. The mean patient age was 10.5 years (range 20 months-20 years) in the iMRI group and 9.8 years (range 2-21 years) in the conventional group (p = 0.41). The mean duration of surgery was 350 minutes in the iMRI group and 243 minutes in the conventional group (p < 0.0001). The mean hospital stay was 8.2 days in the iMRI group, and 6.6 days in the conventional group, and this trended toward significance (p = 0.05). In the first 2 weeks postoperatively, there were 8 reoperations (7.77%) in the conventional group compared with none in the iMRI group, which was not significant in a 2-tailed test (p = 0.11) but trended toward significance in a 1-tailed test (p = 0.06). The significant complications included reoperation for hydrocephalus or infection: 6.8% (conventional) versus 4.8% (iMRI). CONCLUSIONS Intraoperative MR imaging-guided resections resulted in a trend toward reduction in the need for repeat surgery in the immediate 2-week postoperative period compared with conventional pediatric neurosurgical resections for tumor or focal cortical dysplasia. Although there is an increased operative time, the iMRI suite offers a comparable safety and efficacy profile while potentially reducing the per-case cost by diminishing the need for early reoperation.

Alterations in Protein Regulators of Neurodevelopment in the Cerebrospinal Fluid of Infants with Posthemorrhagic Hydrocephalus of Prematurity

Neurological outcomes of preterm infants with posthemorrhagic hydrocephalus are among the worst in newborn medicine. There remains no consensus regarding the diagnosis or treatment of posthemorrhagic hydrocephalus, and the pathological pathways leading to the adverse neurological sequelae are poorly understood. In the current study, we developed an innovative approach to simultaneously identify potential diagnostic markers of posthemorrhagic hydrocephalus and investigate novel pathways of posthemorrhagic hydrocephalus-related neurological disability. Tandem multi-affinity fractionation for specific removal of plasma proteins from the hemorrhagic cerebrospinal fluid samples was combined with high resolution label-free quantitative proteomics. Analysis of cerebrospinal fluid obtained from infants with posthemorrhagic hydrocephalus demonstrated marked differences in the levels of 438 proteins when compared with cerebrospinal fluid from age-matched control infants. Amyloid precursor protein, neural cell adhesion molecule-L1, neural cell adhesion molecule-1, brevican and other proteins with important roles in neurodevelopment showed profound elevations in posthemorrhagic hydrocephalus cerebrospinal fluid compared with control. Initiation of neurosurgical treatment of posthemorrhagic hydrocephalus resulted in resolution of these elevations. The results from this foundational study demonstrate the significant promise of tandem multi-affinity fractionation-proteomics in the identification and quantitation of protein mediators of neurodevelopment and neurological injury. More specifically, our results suggest that cerebrospinal fluid levels of proteins such as amyloid precursor protein or neural cell adhesion molecule-L1 should be investigated as potential diagnostic markers of posthemorrhagic hydrocephalus. Notably, dysregulation of the levels these and other proteins may directly affect ongoing neurodevelopmental processes in these preterm infants, providing an entirely new hypothesis for the developmental disability associated with posthemorrhagic hydrocephalus.

Cerebrospinal fluid levels of amyloid precursor protein are associated with ventricular size in post-hemorrhagic hydrocephalus of prematurity

Background Neurological outcomes of preterm infants with post-hemorrhagic hydrocephalus (PHH) remain among the worst in infancy, yet there remain few instruments to inform the treatment of PHH. We previously observed PHH-associated elevations in cerebrospinal fluid (CSF) amyloid precursor protein (APP), neural cell adhesion molecule-L1 (L1CAM), neural cell adhesion molecule-1 (NCAM-1), and other protein mediators of neurodevelopment. Objective The objective of this study was to examine the association of CSF APP, L1CAM, and NCAM-1 with ventricular size as an early step toward developing CSF markers of PHH. Methods CSF levels of APP, L1CAM, NCAM-1, and total protein (TP) were measured in 12 preterm infants undergoing PHH treatment. Ventricular size was determined using cranial ultrasounds. The relationships between CSF APP, L1CAM, and NCAM-1, occipitofrontal circumference (OFC), volume of CSF removed, and ventricular size were examined using correlation and regression analyses. Results CSF levels of APP, L1CAM, and NCAM-1 but not TP paralleled treatment-related changes in ventricular size. CSF APP demonstrated the strongest association with ventricular size, estimated by frontal-occipital horn ratio (FOR) (Pearson R = 0.76, p = 0.004), followed by NCAM-1 (R = 0.66, p = 0.02) and L1CAM (R = 0.57,p = 0.055). TP was not correlated with FOR (R = 0.02, p = 0.95). Conclusions Herein, we report the novel observation that CSF APP shows a robust association with ventricular size in preterm infants treated for PHH. The results from this study suggest that CSF APP and related proteins at once hold promise as biomarkers of PHH and provide insight into the neurological consequences of PHH in the preterm infant.

Ventricular Zone Disruption in Human Neonates With Intraventricular Hemorrhage

To determine if ventricular zone (VZ) and subventricular zone (SVZ) alterations are associated with intraventricular hemorrhage (IVH) and posthemorrhagic hydrocephalus, we compared postmortem frontal and subcortical brain samples from 12 infants with IVH and 3 nonneurological disease controls without hemorrhages or ventriculomegaly. Birth and expiration estimated gestational ages were 23.0-39.1 and 23.7-44.1 weeks, respectively; survival ranges were 0-42 days (median, 2.0 days). Routine histology and immunohistochemistry for neural stem cells (NSCs), neural progenitors (NPs), multiciliated ependymal cells (ECs), astrocytes (AS), and cell adhesion molecules were performed. Controls exhibited monociliated NSCs and multiciliated ECs lining the ventricles, abundant NPs in the SVZ, and medial vs. lateral wall differences with a complex mosaic organization in the latter. In IVH cases, normal VZ/SVZ areas were mixed with foci of NSC and EC loss, eruption of cells into the ventricle, cytoplasmic transposition of N-cadherin, subependymal rosettes, and periventricular heterotopia. Mature AS populated areas believed to be sites of VZ disruption. The cytopathology and extension of the VZ disruption correlated with developmental age but not with brain hemorrhage grade or location. These results corroborate similar findings in congenital hydrocephalus in animals and humans and indicate that VZ disruption occurs consistently in premature neonates with IVH.

Chemokine and cytokine levels in the lumbar cerebrospinal fluid of preterm infants with post-hemorrhagic hydrocephalus

BackgroundNeuroinflammation has been implicated in the pathophysiology of post-hemorrhagic hydrocephalus (PHH) of prematurity, but no comprehensive analysis of signaling molecules has been performed using human cerebrospinal fluid (CSF).MethodsLumbar CSF levels of key cytokines (IL-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-12, TNF-α, TGF-β1, IFN-γ) and chemokines (XCL-1, CCL-2, CCL-3, CCL-19, CXCL-10, CXCL-11, CXCL-12) were measured using conventional and multiplexed Enzyme-linked Immunosorbent Assays and compared between preterm infants with PHH and those with no known neurological injury. The relationships between individual biomarker levels and specific CSF cell counts were examined.ResultsTotal protein (TP) CSF levels were elevated in the PHH subjects compared to controls. CSF levels of IL-1α, IL-4, IL-6, IL-12, TNF-α, CCL-3, CCL-19, and CXCL-10 were significantly increased in PHH whereas XCL-1 was significantly decreased in PHH. When normalizing by TP, IL-1α, IL-1β, IL-10, IL-12, CCL-3, and CCL-19 levels were significantly elevated compared to controls, while XCL-1 levels remained significantly decreased. Among those with significantly different levels in both absolute and normalized levels, only absolute CCL-19 levels showed a significant correlation with CSF nucleated cells, neutrophils, and lymphocytes. IL-1β and CXCL-10 also were correlated with total cell count, nucleated cells, red blood cells, and neutrophils.ConclusionsNeuroinflammation is likely to be an important process in the pathophysiology of PHH. To our knowledge, this is the first study to investigate CSF levels of chemokines in PHH as well as the only one to show XCL-1 selectively decreased in a diseased state. Additionally, CCL-19 was the only analyte studied that showed significant differences between groups and had significant correlation with cell count analysis. The selectivity of CCL-19 and XCL-1 should be further investigated. Future studies will further delineate the role of these cytokines and chemokines in PHH.

Cerebrospinal Fluid Biomarkers of Pediatric Hydrocephalus

Hydrocephalus (HC) is a common, debilitating neurological condition that requires urgent clinical decision-making. At present, neurosurgeons rely heavily on a patients history, physical examination findings, neuroimaging, and clinical judgment to make the diagnosis of HC or treatment failure (e.g., shunt malfunction). Unfortunately, these tools, even in combination, do not eliminate subjectivity in clinical decisions. In order to improve the management of infants and children with HC, there is an urgent need for new biomarkers to complement currently available tools and enable clinicians to confidently establish the diagnosis of HC, assess therapeutic efficacy/treatment failure, and evaluate current and future developmental challenges, so that every child has access to the resources they need to optimize their outcome and quality of life.

Cerebrospinal fluid biomarkers of infantile congenital hydrocephalus

Introduction Hydrocephalus is a complex neurological disorder with a pervasive impact on the central nervous system. Previous work has demonstrated derangements in the biochemical profile of cerebrospinal fluid (CSF) in hydrocephalus, particularly in infants and children, in whom neurodevelopment is progressing in parallel with concomitant neurological injury. The objective of this study was to examine the CSF of children with congenital hydrocephalus (CHC) to gain insight into the pathophysiology of hydrocephalus and identify candidate biomarkers of CHC with potential diagnostic and therapeutic value. Methods CSF levels of amyloid precursor protein (APP) and derivative isoforms (sAPPα, sAPPβ, Aβ42), tau, phosphorylated tau (pTau), L1CAM, NCAM-1, aquaporin 4 (AQP4), and total protein (TP) were measured by ELISA in 20 children with CHC. Two comparative groups were included: age-matched controls and children with other neurological diseases. Demographic parameters, ventricular frontal-occipital horn ratio, associated brain malformations, genetic alterations, and surgical treatments were recorded. Logistic regression analysis and receiver operating characteristic curves were used to examine the association of each CSF protein with CHC. Results CSF levels of APP, sAPPα, sAPPβ, Aβ42, tau, pTau, L1CAM, and NCAM-1 but not AQP4 or TP were increased in untreated CHC. CSF TP and normalized L1CAM levels were associated with FOR in CHC subjects, while normalized CSF tau levels were associated with FOR in control subjects. Predictive ability for CHC was strongest for sAPPα, especially in subjects ≤12 months of age (p<0.0001 and AUC = 0.99), followed by normalized sAPPβ (p = 0.0001, AUC = 0.95), tau, APP, and L1CAM. Among subjects ≤12 months, a normalized CSF sAPPα cut-point of 0.41 provided the best prediction of CHC (odds ratio = 528, sensitivity = 0.94, specificity = 0.97); these infants were 32 times more likely to have CHC. Conclusions CSF proteins such as sAPPα and related proteins hold promise as biomarkers of CHC in infants and young children, and provide insight into the pathophysiology of CHC during this critical period in neurodevelopment.

Blood Exposure Causes Ventricular Zone Disruption and Glial Activation In Vitro

Intraventricular hemorrhage (IVH) is the most common cause of pediatric hydrocephalus in North America but remains poorly understood. Cell junction-mediated ventricular zone (VZ) disruption and astrogliosis are associated with the pathogenesis of congenital, nonhemorrhagic hydrocephalus. Recently, our group demonstrated that VZ disruption is also present in preterm infants with IVH. On the basis of this observation, we hypothesized that blood triggers the loss of VZ cell junction integrity and related cytopathology. In order to test this hypothesis, we developed an in vitro model of IVH by applying syngeneic blood to cultured VZ cells obtained from newborn mice. Following blood treatment, cells were assayed for N-cadherin-dependent adherens junctions, ciliated ependymal cells, and markers of glial activation using immunohistochemistry and immunoblotting. After 24-48 hours of exposure to blood, VZ cell junctions were disrupted as determined by a significant reduction in N-cadherin expression (p < 0.05). This was also associated with significant decrease in multiciliated cells and increase in glial fibrillary acid protein-expressing cells (p < 0.05). These observations suggest that, in vitro, blood triggers VZ cell loss and glial activation in a pattern that mirrors the cytopathology of human IVH and supports the relevance of this in vitro model to define injury mechanisms.

Cerebrospinal fluid biomarkers of malfunctioning ventriculoperitoneal shunts: a pilot study

Ventriculoperitoneal shunts (VPS) are a critical feature of management of pediatric hydrocephalus. Unfortunately, shunt failure is often unrecognized before significant symptoms and focal signs present, requiring costly emergency room visits and neuroimaging. Ventricular CSF biomarkers of neuropathology and neurodevelopment are emerging as critical predictors of real-time physiology in pediatric hydrocephalus. Moreover, in the future, biomarkers of neuropathology could be pre-operatively analyzed from shunts in question, reducing unnecessary surgical exploration. In this pilot study, CSF samples taken during surgical exploration were compared, hypothesizing that that two critical CSF proteins, amyloid precursor protein (APP) and neural cell adhesion molecule (NCAM-1), known to be elevated in untreated hydrocephalus, may discriminate between functioning and malfunctioning shunts.

Differentiation of cerebrospinal fluid inflammatory biomarkers between neonatal post-hemorrhagic and congenital hydrocephalus

Neonatal Post-hemorrhagic hydrocephalus (PHH) develops partly due to an inflammatory process occurring after intraventricular hemorrhage whereas the majority of congenital hydrocephalus (CH) results from primary and secondary CNS malformations. We hypothesize that cerebrospinal fluid (CSF) content of inflammatory biomarkers is higher in neonatal PHH relative to CH. To test this hypothesis, we measured CSF concentrations of CCL-3, CXCL-12, CX3CL-1, IL-10 and P-selectin in both conditions.