Clinical study of cerebral palsy in 408 children with periventricular leukomalacia

Global Assessment of Palliative Care Need: Serious Health-Related Suffering Measurement Methodology

CONTEXT

Inequities and gaps in palliative care access are a serious impediment to health systems especially in low- and middle-income countries and the accurate measurement of need across health conditions is a critical step to understanding and addressing the issue. Serious Health-related Suffering (SHS) is a novel methodology to measure the palliative care need and was originally developed by The Lancet Commission on Global Access to Palliative Care and Pain Relief. In 2015, the first iteration - SHS 1.0 - was estimated at over 61 million people worldwide experiencing at least 6 billion days of SHS annually as a result of life-limiting and life-threatening conditions.

OBJECTIVES

In this paper, an updated methodology - SHS 2.0 - is presented building on the work of the Lancet Commission and detailing calculations, data requirements, limitations, and assumptions.

METHODS AND RESULTS

The updates to the original methodology focus on measuring the number of people who die with (decedents) or live with (non-decedents) SHS in a given year to assess the number of people in need of palliative care across health conditions and populations. Detail on the methodology for measuring the number of days of SHS that was pioneered by the Lancet Commission, is also shared, as this second measure is essential for determining the health system responses that are necessary to address palliative care need and must be a priority for future methodological work on SHS.

CONCLUSIONS

The methodology encompasses opportunities for applying SHS to future policy making assessment of future research priorities particularly in light of the dearth of data from low- and middle-income countries, and sharing of directions for future work to develop SHS 3.0.

The relation between neuroimaging and visual impairment in children and adolescents with cerebral palsy: A systematic review

OBJECTIVE

The structure-function relation between magnetic resonance imaging (MRI) and visual impairment (VI) in children with cerebral palsy (CP) has not been fully unravelled. The present systematic review aims to summarize the relation between brain lesions on MRI and VI in children and adolescents with CP.

METHODS

PubMed, Embase, Web of Science Core Collection, and Cochrane Database were systematically searched according to the PRISMA checklist. A total of 45 articles met the inclusion criteria.

RESULTS

White matter lesions were most frequently associated with VI. Only 25 studies described lesions within specific structures, mainly in the optic radiations. Only four studies reported on the thalamus. 8.4% of children with CP showed no brain abnormalities on MRI. Diffusion-weighted MRI studies showed that decreased structural connectivity in the optic radiations, superior longitudinal fasciculus, posterior limb of the internal capsule, and occipital lobe is associated with more severe VI.

CONCLUSIONS

All types of brain lesions lead to visual dysfunctions, arguing for a comprehensive visual assessment in all children with CP. Whereas white matter damage is a well-known contributor, the exact contribution of specific visual structures requires further investigation, to enable early prediction, detection, and intervention.

Clinical characteristics and long-term neurodevelopmental outcomes of leukomalacia in preterm infants and term infants: a cohort study

BACKGROUND

Leukomalacia is a serious form of neonatal brain injury that often leads to neurodevelopmental impairment, and studies on neonatal leukomalacia and its long-term outcomes are lacking. The aim of this study was to analyze the clinical manifestations, imaging features, and long-term neurodevelopmental outcomes in preterm infants and term infants with leukomalacia.

METHODS

Newborns diagnosed with leukomalacia by head magnetic resonance imaging (MRI) and who were admitted to intensive care units from January 2015 to June 2020 were enrolled. All infants were followed up to June 2022 (2-7 years old), and their neurodevelopmental outcomes were evaluated. The clinical data and long- term outcomes of preterm infants and term infants was analyzed by Chi-square tests.

RESULTS

A total of 218 surviving infants with leukomalacia including 114 preterm infants and 104 term infants completed the follow-up. The major typesof leukomalacia on MRI were periventricular leukomalacia in the preterm group and subcortical cystic leukomalacia in the term group, respectively (χ2 = 55.166; p < 0.001). When followed up to 2-7 years old, the incidence of neurodevelopmental impairment in the preterm group and term group was not significantly different (χ2 = 0.917; p = 0.338). However, the incidence of cerebral palsy (CP) in the preterm group was significantly higher (χ2 = 4.896; p = 0.027), while the incidence of intellectual disability (ID) (χ2 = 9.445; p = 0.002), epilepsy (EP) (χ2 = 23.049; p < 0.001), and CP combined with ID andEP (χ2 = 4.122; p = 0.042) was significantly lower than that in the term group.

CONCLUSIONS

Periventricular leukomalacia mainly occurred in preterm infants while subcortical cystic leukomalacia was commonly seen in term infants. Although the long-term neurodevelopmental outcomes of leukomalacia were both poor, preterm infants were more prone to CP, while term infants were more prone to ID, EP, and the combination of CP with ID and EP.

Exosomal Lipid Biomarkers of Oligodendrocyte Pathology to Predict Scoliosis in Children with Cerebral Palsy

Introduction

Cerebral Palsy (CP), the most common cause of disability in children, is phenotypically heterogeneous. Approximately 20% of cases develop severe scoliosis. A pathological hallmark of CP is periventricular leukomalacia (PVL), which is due to dysmyelination, suggesting the possibility of a lipidomic abnormality. Risk factors for CP include perinatal hypoxia, prematurity, multiple gestation, ischemia, infection, and maternal alcohol consumption. There is evidence for low serum levels of omega-3 (ω-3) fatty acids in CP patients, and separately in idiopathic scoliosis. Many effects of free fatty acids (FFAs) are mediated via specific G protein-coupled free fatty acid receptors (FFARs), which play essential roles as nutritional and signaling molecules. FFAs, including ω-3, and their receptors are involved in the development and metabolism of oligodendrocytes (OLs), and are critical to myelination. Thus, the cases of CP that will develop severe scoliosis might be those in which there is a deficiency of ω-3, FFARs, or other lipidomic abnormality that is detectable early in the plasma. If so, we might be able to predict scoliosis and prevent it with dietary supplementation.

Methods

Blood samples were collected from four groups of patients at the Philadelphia Shriners Children's Hospital (SCH-P): 1) patients with CP; 2) severe scoliosis (>40o); 3) CP plus scoliosis; and 4) non-impaired controls stratified by age (2-18 yrs), gender, and race/ethnicity, under an IRB-approved protocol. Serum proteins and RNA were purified, and OL-derived exosomes (OL-Es) isolated, using myelin basic protein (MBP) as a late OL marker. Protein was used for the detection of MBP and FFAR by enzyme-linked immunosorbent assays (ELISAs), and by flow cytometry. RNA was assayed by digital droplet polymerase chain reaction (ddPCR) for OL markers and FFAR expression.

Results

FFAR and MBP proteins were downregulated in each of the three patient groups compared to controls, and this difference was greatest in both patients with CP plus scoliosis.

Conclusion

Altogether, MBP and FFAR levels were reduced in OL-Es from both children with CP plus scoliosis. The lipid abnormalities specific to CP with scoliosis were concentrated in OLs. Our data might i) suggest therapeutic targets to reduce dysmyelination and scoliosis in CP, ii) predict which children are at risk for developing scoliosis, iii) lead to therapeutic trials of fatty acids for CP and other dysmyelinating neurological disorders.

Long-term analysis of adrenocorticotropic hormone monotherapy for infantile epileptic spasms syndrome with periventricular leukomalacia

PURPOSE

Infantile epileptic spasms syndrome (IESS) with periventricular leukomalacia (PVL) has a poor neurological prognosis. Adrenocorticotropic hormone (ACTH) and vigabatrin therapies are the recommended first-line treatments for IESS. However, ACTH monotherapy for IESS with PVL has not been studied in detail. We analysed long-term outcomes of ACTH monotherapy for IESS with PVL.

METHODS

We retrospectively examined 12 patients with IESS and PVL at Saitama Children's Medical Center between January 1993 and September 2022. We evaluated seizure outcomes 3 months post-ACTH therapy and at the last visit. We also assessed electroencephalography findings and developmental outcomes. A positive response was defined as complete remission of epileptic spasms, no other seizure types, and hypsarrhythmia resolution post-ACTH therapy.

RESULTS

The median onset age of epileptic spasms was 7 (range: 3-14) months. The median age at initiation of ACTH therapy was 9 (7-17) months. Seven of 12 patients (58.3%) showed a positive response. The median age at the last visit was 5 years and 6 months (1 year and 5 months-22 years and 2 months). At the last visit, only 2 of 7 initial responders remained seizure-free who demonstrated normal electroencephalography findings within 1-month post-ACTH therapy. Patients with epileptic discharge in the parieto-occipital region within 1-month post-ACTH therapy showed relapse of epileptic spasms or other seizure types.

CONCLUSION

Patients having epileptic discharge in the parietal or occipital regions on electroencephalography within 1-month post-ACTH therapy may be at a high risk of epileptic spasm recurrence or other seizure types in the long term.

Use of Thalamus L-Sign to Differentiate Periventricular Leukomalacia From Neurometabolic Disorders

PURPOSE

To assess the diagnostic value of the thalamus L-sign on magnetic resonance imaging (MRI) in distinguishing between periventricular leukomalacia and neurometabolic disorders in pediatric patients.

METHODS

In this retrospective study, clinical and imaging information was collected from 50 children with periventricular leukomalacia and 52 children with neurometabolic disorders. MRI was used to evaluate the L-sign of the thalamus (ie, injury to the posterolateral thalamus) and the lobar distribution of signal intensity changes. Age, sex, gestational age, and level of Gross Motor Function Classification System (only for periventricular leukomalacia) constituted the clinical parameters. Statistical evaluation of group differences for imaging and clinical variables were conducted using univariable statistical methods. The intra- and inter-observer agreement was evaluated using Cohen's kappa. Univariable or multivariable logistic regression was employed for selection of variables, determining independent predictors, and modeling.

RESULTS

The thalamus L-sign was observed in 70% (35/50) of patients in the periventricular leukomalacia group, but in none of the patients with neurometabolic disorder (P < .001). The gestational age between groups varied significantly (P < .001). Involvement of frontal, parietal, and occipital lobes differed significantly between groups (P < .001). In the logistic regression, the best model included negative thalamus L-sign and gestational age, yielding an area under the curve, accuracy, sensitivity, specificity, and precision values of 0.995, 96.1%, 96%, 96.2%, and 96%, respectively. Both the lack of thalamus L-sign and gestational age were independent predictors (P < .001).

CONCLUSIONS

The thalamus L-sign and gestational age may be useful in distinguishing between periventricular leukomalacia and neurometabolic disorders.

Application of brain ultrasound in premature infants with brain injury

Brain injury is the main factor affecting the development and prognosis of the nervous system in premature infants. Early diagnosis and treatment are of great significance in reducing mortality and disability and improving the prognosis of premature infants. Craniocerebral ultrasound has become an important medical imaging method for evaluating the brain structure of premature infants due to its advantages of being non-invasive, cheap, simple, and bedside dynamic monitoring since it was applied to neonatal clinical practice. This article reviews the application of brain ultrasound to common brain injuries in premature infants.

Neuroradiological Mimics of Periventricular Leukomalacia

AIM

Periventricular leukomalacia (PVL) is a term reserved to describe white matter injury in the premature brain. In this review article, the authors highlight the common and rare pathologies mimicking the chronic stage of PVL and propose practical clinico-radiological criteria that would aid in diagnosis and management.

METHODS AND RESULTS

The authors first describe the typical brain MRI (magnetic resonance imaging) features of PVL. Based on their clinical presentation, pathologic entities and their neuroimaging findings were clustered into distinct categories. Three clinical subgroups were identified: healthy children, children with stable/nonprogressive neurological disorder, and those with progressive neurological disorder. The neuroradiological discriminators are described in each subgroup with relevant differential diagnoses. The mimics were broadly classified into normal variants, acquired, and inherited disorders.

CONCLUSIONS

The term "PVL" should be used appropriately as it reflects its pathomechanism. The phrase "white matter injury of prematurity" or "brain injury of prematurity" is more specific. Discrepancies in imaging and clinical presentation must be tread with caution and warrant further investigations to exclude other possibilities.

[Modern possibilities of diagnosing lesions of the visual analyzer in perinatal lesions of the central nervous system in full-term and premature infants]

The article provides an overview of current neuro-ophthalmological diagnostic capabilities in patients with perinatal lesions. The main attention is paid to the diagnosis of patients with periventricular leukomalacia and peri- and intraventricular hemorrhages. The most relevant methods of neuro-ophthalmological diagnosis in hypoxic-ischemic CNS lesions are covered. The functions and peculiarities of blood supply of the germinal matrix are described. The importance of the use of optical coherence tomography and visual evoked potential recording in full-term and premature infants with visual pathway and/or visual cortex lesions in brain lesions is discussed. The conclusion emphasizes the need for an interdisciplinary approach in the examination of children with perinatal CNS lesions.

Selective Motor Control is a Clinical Correlate of Brain Motor Tract Impairment in Children with Spastic Bilateral Cerebral Palsy

BACKGROUND AND PURPOSE

Selective voluntary motor control is an important factor influencing gross motor function, interjoint coordination, and the outcome of hamstring-lengthening surgery in spastic cerebral palsy. Using DTI, we investigated whether selective voluntary motor control would show strong correlations with WM motor tract microstructure and whether selective voluntary motor control is more sensitive to global WM impairment than gross motor function.

MATERIALS AND METHODS

Children with spastic bilateral cerebral palsy born preterm and typically developing children were recruited. The Selective Control Assessment of the Lower Extremity (SCALE) and Gross Motor Function Measure (GMFM) were assessed in participants with cerebral palsy. Participants underwent brain MR imaging to collect DWI data. Tract-Based Spatial Statistics was used to analyze the WM for between-group differences and correlations with SCALE and GMFM. ROI analyses compared motor regions.

RESULTS

Twelve children with cerebral palsy (mean age, 11.5 years) and 12 typically developing children (mean age, 10.3 years) participated. Altered DTI outcomes were found throughout the whole brain for the cerebral palsy group. SCALE, developed to evaluate selective voluntary motor control in cerebral palsy, showed significant positive correlations with fractional anisotropy in more WM voxels throughout the whole brain and for motor regions, including the corticospinal tract and corpus callosum, compared with GMFM. A significant negative correlation between radial diffusivity and SCALE, but not GMFM, was found within the corpus callosum.

CONCLUSIONS

SCALE was a more sensitive clinical correlate of motor and whole-brain WM tract impairment in children with spastic bilateral cerebral palsy, suggesting greater anisotropy and myelination in these regions for those with higher selective voluntary motor control.

Evaluation of the relationship between cranial magnetic resonance imaging findings and clinical status in children with cerebral palsy

Background/aim

The objective of this study was to evaluate the relationship between cranial magnetic resonance imaging (MRI) findings and clinical features in cerebral palsy (CP).

Materials and methods

Children aged 3 to 18 years, who were followed with the diagnosis of CP between January 2012 and September 2015, were included. The type of CP was classified using the European Cerebral Palsy Monitoring Group’s classification system and then, patients were divided into two groups as spastic or nonspastic groups. The Gross Motor Function Classification System (GMFCS) was used to determine the level of mobility. According to the GMFCS, levels 1, 2, and 3 were grouped as mobile, and levels 4 and 5 were grouped as immobile. Cranial MRI findings were reevaluated by a voluntarily radiologist and grouped as periventricular leukomalacia (PVL) (grades 1, 2, and 3), cerebral atrophy, migration anomaly, cerebellar involvement, basal ganglion involvement, and normal MRI findings.

Results

Sixty-two patients were enrolled. The rate of mobile patients did not differ between the spastic and nonspastic groups. The incidence of PVL was significantly higher in cases of prematurity and spastic CP (p < 0.05). The rate of mobilization was significantly lower and the rate of epilepsy was significantly higher in patients with PVL. Immobile patients were more common among cases of grade 3 PVL (p < 0.05).

Conclusion

The most common cranial MRI pathology was PVL, and the presence of PVL and its grade might help clinically assess the patient’s CP type and level of mobilization. While pathology was observed mostly in cranial MRI in cases of CP with similar clinical features, the fact that cranial MRI was completely normal for 14.5% of the cases suggests that there may be some pathologies that we could not identify with today’s imaging technology.

Neurodevelopmental outcomes after ventriculoperitoneal shunt placement in children with non-infectious hydrocephalus: a meta-analysis

BACKGROUND

Hydrocephalus is diagnosed when an accumulating amount of cerebrospinal fluid (CSF) fails to circulate and/or absorbed in the ventricular system. Based on its etiology, hydrocephalus can be classified into infectious and non-infectious hydrocephalus. In children, non-infectious hydrocephalus includes congenital hydrocephalus, posthemorrhagic hydrocephalus, neural tube defect-related hydrocephalus, and tumor-related hydrocephalus. Regardless of the cause, a CSF diversion device is placed to divert the excess fluid from the ventricles into peritoneal cavity. Among all, ventriculoperitoneal (VP) shunt is arguably the most commonly used CSF diversion device to date. Until now, the long-term neurodevelopmental impact of VP shunt placement in non-infectious hydrocephalus patients remained unclear.

OBJECTIVE

This study aims to evaluate the neurodevelopmental outcomes in children with non-infectious hydrocephalus who had VP shunt placement.

MATERIALS AND METHODS

Systematic searches were performed using PubMed, Google Scholar, Scopus databases, and reference lists. Publications that fulfilled the inclusion criteria were included in the meta-analysis. Calculation of Mantel-Haezel risk ratio (RR) was applied, and heterogeneity index (I²) test was used to evaluate the existence of heterogeneity in all studies. Risk of bias was assessed based on the criteria from the Newcastle-Ottawa Scale (NOS).

RESULTS

Of the 1929 studies identified, 12 publications were concluded to have fulfilled the inclusion criteria. Results from the meta-analysis showed that the risks of cerebral palsy, visual and hearing impairment, epilepsy, or seizures are significantly higher in children with non-infectious hydrocephalus who already had VP shunt placement (shunted non-infectious hydrocephalus, S-NIH) compared to that of the healthy control. The meta-analysis on intelligent quotient (IQ) and mental development index (MDI) showed that S-NIH children tend to score lower IQ and acquire risk of having mental development delay. On motoric development, S-NIH children scored lower motoric score and have significantly higher risk of motor development delay compared to control. Although normal children tend to have more internalizing behavior compared to S-NIH children, overall assessment on the risk of behavioral abnormalities showed that the differences between these two groups are insignificant.

CONCLUSION

S-NIH children have significantly higher risks of disabilities and mental and motoric development delays; thus, planning on continuous rehabilitation for children with non-infectious hydrocephalus who already had placement of VP shunt is important to acquire their optimum potentials and quality of life.

Consensus Approach for Standardizing the Screening and Classification of Preterm Brain Injury Diagnosed With Cranial Ultrasound: A Canadian Perspective

Acquired brain injury remains common in very preterm infants and is associated with significant risks for short- and long-term morbidities. Cranial ultrasound has been widely adopted as the first-line neuroimaging modality to study the neonatal brain. It can reliably detect clinically significant abnormalities that include germinal matrix and intraventricular hemorrhage, periventricular hemorrhagic infarction, post-hemorrhagic ventricular dilatation, cerebellar hemorrhage, and white matter injury. The purpose of this article is to provide a consensus approach for detecting and classifying preterm brain injury to reduce variability in diagnosis and classification between neonatologists and radiologists. Our overarching goal with this work was to achieve homogeneity between different neonatal intensive care units across a large country (Canada) with regards to classification, timing of brain injury screening and frequency of follow up imaging. We propose an algorithmic approach that can help stratify different grades of germinal matrix-intraventricular hemorrhage, white matter injury, and ventricular dilatation in very preterm infants.

Changes of Structural Brain Network Following Repetitive Transcranial Magnetic Stimulation in Children With Bilateral Spastic Cerebral Palsy: A Diffusion Tensor Imaging Study

Introduction: Bilateral spastic cerebral palsy (BSCP) is the most common subtype of cerebral palsy (CP), which is characterized by various motor and cognitive impairments, as well as emotional instability. However, the neural basis of these problems and how repetitive transcranial magnetic stimulation (rTMS) can make potential impacts on the disrupted structural brain network in BSCP remain unclear. This study was aimed to explore the topological characteristics of the structural brain network in BSCP following the treatment of rTMS. Methods: Fourteen children with BSCP underwent 4 weeks of TMS and 15 matched healthy children (HC) were enrolled. Diffusion tensor imaging (DTI) data were acquired from children with bilateral spastic cerebral palsy before treatment (CP1), children with bilateral spastic cerebral palsy following treatment (CP2) and HC. The graph theory analysis was applied to construct the structural brain network. Then nodal clustering coefficient (C _i ) and shortest path length (L _i ) were measured and compared among groups. Results: Brain regions with significant group differences in C _i were located in the left precental gyrus, middle frontal gyrus, calcarine fissure, cuneus, lingual gyrus, postcentral gyrus, inferior parietal gyri, angular gyrus, precuneus, paracentral lobule and the right inferior frontal gyrus (triangular part), insula, posterior cingulate gyrus, precuneus, paracentral lobule, pallidum. In addition, significant differences were detected in the L _i of the left precental gyrus, lingual gyrus, superior occipital gyrus, middle occipital gyrus, superior parietal gyrus, precuneus and the right median cingulate gyrus, posterior cingulate gyrus, hippocampus, putamen, thalamus. Post hoc t-test revealed that the CP2 group exhibited increased C _i in the right inferior frontal gyrus, pallidum and decreased L _i in the right putamen, thalamus when compared with the CP1 group. Conclusion: Significant differences of node-level metrics were found in various brain regions of BSCP, which indicated a disruption in structural brain connectivity in BSCP. The alterations of the structural brain network provided a basis for understanding of the pathophysiological mechanisms of motor and cognitive impairments in BSCP. Moreover, the right inferior frontal gyrus, putamen, thalamus could potentially be biomarkers for predicting the efficacy of TMS.

Prevalence and demographic characteristics of comorbid epilepsy in children and adolescents with cerebral palsy: a nationwide population-based study

INTRODUCTION

The nationwide prevalence of cerebral palsy (CP) is unknown due to the lack of a population-based registration system for CP in Taiwan. This study was the largest nationwide, population-based, cross-sectional study to estimate the prevalence of CP, prevalence rates of comorbid epilepsy in patients with CP, and association with socioeconomic status (SES) in Taiwan. The crude prevalence rate and age- and gender-specific prevalence rates were estimated.

METHODS

A total of 8419 patients with CP were enrolled, and the estimated prevalence of CP was 1.76‰ in the pediatric population and 1.51‰ and 1.98‰ in girls and boys, respectively. The prevalence rate of epilepsy in patients with CP was 29.8%.

RESULTS

The result revealed a higher prevalence of CP and epileptic CP in members of families with lower insurance premiums than those with higher insurance premiums and those from East Taiwan compared with those from other areas of Taiwan. Moreover, a higher prevalence of CP is shown in rural area than urban area.

DISCUSSION

SES and geographic variables were significantly associated with the risk of epilepsy in children with CP. Patients with epileptic CP had a higher odds ratio of several neuropsychiatric diseases, including mental retardation, ophthalmologic problems, hearing impairment, and hydrocephalus.

Ventriculomegaly in very-low-birthweight infants with Down syndrome

AIM

The prevalence of Down syndrome in infants with fetal ventriculomegaly is 5% to 10%; however, the converse, the prevalence of cerebral ventriculomegaly in live-born infants with Down syndrome, is not well established. Because cranial ultrasounds are performed on most very-low-birthweight (VLBW) infants (birthweight <1500g), our aim was to examine ultrasound abnormalities of VLBW infants to determine prevalence of ventriculomegaly and intraventricular hemorrhage (IVH) in VLBW infants with Down syndrome, and whether VLBW infants with Down syndrome are at higher risk for cranial ultrasound abnormalities, compared with the already elevated risk in other VLBW infants.

METHOD

This study comprised retrospective analysis of data from Pediatrix BabySteps Clinical Data Warehouse. The study population consisted of 121 736 VLBW infants (61 869 males, 59 867 females), born between 1996 and 2013, of whom 441 had Down syndrome (233 males, 208 females; mean gestational age 30wks, standard deviation [SD] 2.8wks). Logistic regression was used to calculate odds of ventriculomegaly and IVH for Down syndrome.

RESULTS

Prevalence of ventriculomegaly in Down syndrome was 5.2% compared with 0.8% in other VLBW infants. Multivariate analysis indicated 5.8× odds (95% confidence interval [CI] 3.4-9.7) of ventriculomegaly in Down syndrome and 0.9× odds (95% CI 0.7-1.1) of IVH for Down syndrome.

INTERPRETATION

Very preterm infants with Down syndrome are at increased risk for ventriculomegaly (but not for IVH) compared with other infants born very preterm.

Apoptosis of Oligodendrocytes during Early Development Delays Myelination and Impairs Subsequent Responses to Demyelination

During mammalian development, myelin-forming oligodendrocytes are generated and axons ensheathed according to a tightly regulated sequence of events. Excess premyelinating oligodendrocytes are eliminated by apoptosis and the timing of the onset of myelination in any specific CNS region is highly reproducible. Although the developing CNS recovers more effectively than the adult CNS from similar insults, it is unknown whether early loss of oligodendrocyte lineage cells leads to long-term functional deficits. To directly assess whether the loss of oligodendrocytes during early postnatal spinal cord development impacted oligodendrogenesis, myelination, and remyelination, transgenic mouse lines were generated in which a modified caspase-9 molecule allowed spatial and temporal control of the apoptotic pathway specifically in mature, myelin basic protein expressing oligodendrocytes (MBP-iCP9). Activating apoptosis in MBP(+) cells of the developing spinal cord during the first postnatal week inhibited myelination. This inhibition was transient, and the levels of myelination largely returned to normal after 2 weeks. Despite robust developmental plasticity, MBP-iCP9-induced oligodendrocyte apoptosis compromised the rate and extent of adult remyelination. Remyelination failure correlated with a truncated proliferative response of oligodendrocyte progenitor cells, suggesting that depleting the oligodendrocyte pool during critical developmental periods compromises the regenerative response to subsequent demyelinating lesions.

SIGNIFICANCE STATEMENT

This manuscript demonstrates that early insults leading to oligodendrocyte apoptosis result in the impairment of recovery from demyelinating diseases in the adult. These studies begin to provide an initial understanding of the potential failure of recovery in insults, such as periventricular leukomalacia and multiple sclerosis.