Survival of transplanted neurotrophin-3 expressing human neural stem cells and motor function in a rat model of spinal cord injury

BACKGROUND： Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation, Schwann cell transplantation, olfactory ensheathing cell transplantation, and embryonic neural tissue transplantation. However, there is a need for improved outcomes. OBJECTIVE： To investigate the repair feasibility for rat spinal cord injury using human neural stem cells （hNSCs） genetically modified by lentivirus to express neurotrophin-3. DESIGN, TIME AND SETTING： In vitro cell biological experiment and in vivo randomized, controlled genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People＇s Hospital of Yibin, China from March 2006 to December 2007. MATERIALS： A total of 64 adult, female, Wistar rats were used for the in vivo study. Of them, 48 rats were used to establish models of spinal cord hemisection, and were subsequently equally and randomly assigned to model, genetically modified hNSC, and normal hNSC groups. The remaining 16 rats served as normal controls. METHODS： hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3. Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension （5 × 10^5） was injected into the rat spinal cord following T10 spinal cord hemisection. A total of 5μL Dulbecco＇s-modified Eagle＇s medium was infused into the rat spinal cord in the model grop. Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry. Motor function was evaluated using the Basso, Beattie, and Bresnahan （BBB） scale. MAIN OUTCOME MEASURES： The following parameters were measured： expression of neurotrophin-3 produced by genetically modified hNSCs, transgene expression and survival of hNSCs in rats, motor function in rats. RESULTS： hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3. The transplanted hNSCs primarily gathered at, or around, the injection site two weeks following transplantation, and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site. In addition, hNSCs were observed 10 weeks after transplantation. At week 4, BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups, compared with the model group （P 〈 0.05）, and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group （P 〈 0.05）. CONCLUSION： hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.

Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

Osteogenesis imperfecta（OI） comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI,many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B（ACVR2B） in a mouse model of type Ⅲ OI（oim）. Treatment of 12-week-old oim mice with ACVR2 B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy,wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system.

罗伦佐的油治疗89例无症状性肾上腺脑白质营养不良患者的随访研究

Objectives: To identify asymptomatic boys with X-linked adrenoleukodystrophy who have a normal magnetic resonance image (MRI), and to assess the effect of 4:1 glyceryl trioleate-glyceryl trierucate (Lorenzo’s oil) on disease progression. Method: Eighty-nine boys (mean±SD baseline age, 4.7±4.1 years; range, 0.2-15 years) were identified by a plasma very long-chain fatty acids assay used to screen at-risk boys. All were treated with Lorenzo’s oil and moderate fat restriction. Plasma fatty acids and clinical status were followed for 6.9±2.7 years. Changes in plasma hexacosanoic acid levels were assessed by measuring the length-adjusted area under the curve, and a proportional hazards model was used to evaluate association with the development of abnormal MRI results and neurological abnormalities. Results: Of the 89 boys, 24%developed MRI abnormalities and 11%developed both neurological and MRI abnormalities. Abnormalities occurred only in the 64 patients who were aged 7 years or younger at the time therapy was started. There was significant association between the development of MRI abnormalities and a plasma hexacosanoic acid increase. (For a 0.1-μg/mL increase in the length-adjusted area under the curve for the hexacosanoic acid level, the hazard ratio for incident MRI abnormalities in the whole group was 1.36; P=.01; 95%confidence interval, 1.07-1.72.) Results for patients aged 7 years or younger were similar (P=.04). Conclusions: In this single-arm study, hexacosanoic acidreductionbyLorenzo’s oil was associated with reduced risk of developing MRI abnormalities. We recommend Lorenzo’s oil therapy in asymptomatic boys with X-linked adrenoleukodystophy who have normal brain MRI results.

通过极长链脂肪酸检测从无症状的肾上腺脑白质营养不良患者中筛查肾上腺功能减退者

Objective: Plasma assay for very long- chain fatty acids has made it possibl e to perform large- scale screening of at- risk individuals to identify asympt omatic patients with X- linked adrenoleukodystrophy (X- ALD). We evaluated the burden of undiagnosed adrenal insufficiency in 49 such patients (age, 4.5 ± 3 .5 years). Study design: Serum adrenocorticotropic hormone (ACTH) and standard- dose ACTH stimulation test were performed at the baseline and followed prospect ively until initiation of adrenal replacement therapy (follow- up, 2 ± 1.7 ye ars). Results: At baseline, 39 (80% ) patients had impaired adrenal function, s erum ACTH levels were elevated in 34 (69% ) patients, and ACTH stimulation test was abnormal in 21(43% ) patients. There was a moderate association between Se rum ACTH and age at baseline, (r = 0.32, P = .05). By the end of follow- up, 86 % of patients had borderline or overt adrenal insufficiency (age of onset, 4.8 ± 3.7 years). Conclusions: We detected a high prevalence of unrecognized adre nocortical insufficiency in asymptomatic boys with X- ALD. It is known to be a frequent cause of morbidity and can be prevented by careful monitoring, early id entification of impaired adrenal reserve, and timely initiation of therapy. It m anifests early and before onset of neurologic symptoms, suggesting X- ALD as a candidate disorder for neonatal screening.

Neonatal opioid exposure:public health crisis and novel neuroinflammatory disease

Substance use,specifically the use of prescription and non-prescription opioids among pregnant women,is a major public health issue and chief contributor to the opioid crisis.The prevalence of Neonatal Opioid Withdrawal Syndrome has risen 5-fold in the past decade,and is a well-recognized consequence of perinatal opioid exposure.By contrast,the long-term damage to the developing brain from opioid medications is just beginning to be recognized as a serious concern.Published data suggest that opioid exposure commencing in utero negatively affects the maturation of the neural-immune system,and trajectory of central nervous system development.Methadone induces peripheral immune hyper-reactivity,lasting structural and microstructural brain injury,and significant deficits in executive function and cognitive control in adult animals following in utero exposure.Thus,to address the cascading public health crisis stemming from the multitude of infants with in utero opioid exposure who will grow up with altered neurodevelopmental trajectories,rigorous preclinical,mechanistic studies are required.Such studies will define the long-term sequelae of prenatal opioid exposure in an effort to develop appropriate and targeted interventions.Specifically,the development of novel fluid,neuroimaging and biobehavioral biomarkers will be the most useful to aid in early identification and treatment of opioid exposed infants with the greatest risk of poor clinical outcomes.These studies will be essential to understand how in utero insults determine brain structure and function in adulthood,and what targeted interventions will be required to improve longterm outcomes in the countless children being born exposed to opioids each year.

Potential for treatment of severe autism in tuberous sclerosis complex

The Food and Drug Administration(FDA) has approved two mechanismbased treatments for tuberous sclero-sis complex(TSC)-everolimus and vigabatrin. However, these treatments have not been systematically studied in individuals with TSC and severe autism. The aim of this review is to identify the clinical features of severe autism in TSC, applicable preclinical models, and potential barriers that may warrant strategic planning in the design phase of clinical trial development. A comprehensive search strategy was formed and searched across Pub Med, Embase and SCOPUS from their inception to 2/21/12, 3/16/12, and 3/12/12 respectively. After the final search date, relevant, updated articles were selected from Pub Med abstracts generated electronically and emailed daily from Pub Med. The references of selected articles were searched, and relevant articles were selected. A search of clinicaltrials.gov was completed using the search term "TSC" and "tuberous sclerosis complex". Autism has been reported in as many as 60% of individuals with TSC; however, review of the literature revealed few data to support clear classification of the severity of autism in TSC. Variability was identified in the diagnostic approach, assessment of cognition, and functional outcome among the reviewed studies and case reports. Objective outcome measures were not used in many early studies; however, diffusion tensor imaging of white matter, neurophysiologic variability in infantile spasms, and cortical tuber subcategories were examined in recent studies and may be useful for objective classification of TSC in future studies. Mechanism-based treatments for TSC are currently available. However, this literature review revealed two potential barriers to successful design and implementation of clinical trials in individuals with severe autism-an unclear definition of the population and lack of validated outcome measures. Recent studies of objective outcome measures in TSC and further study of applicable preclinical models present an opportunity to overcome these barriers.

无神经系统症状的X连锁肾上腺白质营养不良男孩的认知功能评估

Background: Various studies have demonstrated abnormal neuropsychological function in boys with the childhood cerebral phenotype of X-linked adrenoleukodystrophy. Not much is known about the cognitive function of neurologically asymptomatic boys with X-linked adrenoleukodystrophy who have normal brain magnetic resonance imaging results. Objective: To describe the cognitive profile of 52 neurologically asymptomatic boys with X-linked adrenoleukodystrophy (mean± SD age, 6.7± 3.6 years). Methods: Neuropsychological tests included evaluation of IQ (full-scale IQ, verbal IQ, and performance IQ), 5 major cognitive domains (language, visuospatial skills, perception, visuomotor or graphomotor skills, memory, and attention or executive function), adaptive skills, and academic achievement. Standardized z scores relative to ageappropriate published norms were generated. Association between age and cognitive performance was evaluated using nonparametric Spearman rank correlation and robust median regression adjusting for full-scale IQ and socioeconomic status. Results: All but 4 patients had normal cognitive function. There was a negative correlation between age and visual perception as well as age and visuomotor skills after adjustment for full-scale IQ and socioeconomic status. Conclusions: This study provides, to our knowledge, the first evidence of overall normal cognitive function in neurologically and radiologically normal boys with X-linked adrenoleukodystrophy, indicating no evidence of neurodevelopmental abnormalities despite the inherent ABCD1 mutation. Subtle deterioration with age was observed in some functional domains. This suggests that prevention and timely institution of therapy can potentially preserve cognitive function seen in patients with the cerebral X-linked adrenoleukodystrophy phenotype. X-linked adrenoleukodystrophy should be considered a candidate disorder for neonatal screening.

肾上腺脊髓神经病变的感觉运动功能和轴突完整性

Background: Gait abnormalities and sensorimotor disturbances are principal defects in adrenomyeloneuropathy (AMN). However, to our knowledge, their association with overall impairment and neuroanatomical changes has not been defined. Objectives: To understand how sensorimotor impairments create mobility deficits and to analyze how these impairments are related to specific metrics of axonal integrity. Design: Cross-sectional study assessing impairments, including vibration sensation, strength, spasticity, and global measures of walking and balance. Fractional anisotropy was measured to evaluate the integrity of the corresponding brainstem tracts. Participants: Men with AMN and healthy control subjects. Results: Individuals with sensory loss only showed minimal walking deficits. Concomitant strength and sensory loss resulted in slower walking, with abnormal knee control; increased spasticity led to an exaggerated trunk motion and a knee-flexed (crouched) posture. Hip strength was an independent predictor of walking velocity in subjects with AMN. Subjects with sensory loss only had greater sway amplitudes during standing balance testing, which did not worsen with additional impairments. There were significant associations among sway amplitude, great toe vibration sense, and dorsal column fractional anisotropy. Brainstem fractional anisotropy in AMN was significantly negatively correlated with impairment, indicating that overall tract integrity is associated with sensorimotor abnormalities in AMN. Conclusions: Impairment measures capture specific abnormalities in walking and balance that can be used to direct rehabilitation therapy in AMN. Tract-specific magnetic resonance imaging metrics, such as fractional anisotropy (used herein to evaluate structure-function relationships), significantly reflect disease severity in AMN.

进行性腔隙性脑白质病:一种新型儿童期疾病

We report 19 patients with a previously undelineated neurodegenerative syndrome characterized by episodic acute onset of irritability or neurological deficits between 2 months and 3.5 years of age, followed by steady or intermittent clinical deterioration. Seven children died between 11 months and 14 years of age. Cranial magnetic resonance imaging (MRI) shows patchy leukoencephalopathy with cavities, and vascular permeability, in actively affected regions. Early lesions affect corpus callosum and centrum semiovale, with or without cerebellar or cord involvement. After repeated episodes, areas of tissue loss coalesce with older lesions to become larger cystic regions in brain or spinal cord. Diffuse spasticity, dementia, vegetative state, or death ensues. Gray matter is spared until late in the course. In some, incomplete clinical or MRI recovery occurs after episodes. The clinical course varies from rapid deterioration to prolonged periods of stability that are unpredictable by clinical or MRI changes. Elevated levels of lactate in brain, blood, and cerebrospinal fluid, abnormal urine organic acids, and changes in muscle respiratory chain enzymes are present but inconsistent, without identifiable mitochondrial DNA mutations or deletions. Pathological studies show severe loss of myelin sparing U-fibers, axonal disruption, and cavitary lesions without inflammation. Familial occurrence and consanguinity suggest autosomal recessive inheritance of this distinct entity.

“纯”肾上腺脊髓神经病患者大脑内轴突病变的分光镜检测证据

Background: Adrenomyeloneuropathy (AMN) is the adult variant of X-linked adre noleukodystrophy. The disease pathology is usually limited to spinal cord and pe ripheral nerves, and when this is the case, it is referred to as “pure" AMN. Hi stopathology shows cerebral involvement even in pure AMN; however, not much is k nown about the nature, extent, and clinical relevance of these findings. Objecti ve: To investigate brain involvement in AMN patients with normal MRI, employing multislice MR spectroscopic imaging. Methods: Twelve men with pure AMN were comp ared with 19 age-matched healthy volunteers.Metabolite ratios (N-acetylasparta te [NAA]/choline [Cho],NAA/creatine [Cr], and Cho/Cr) were measured from seven b rain regions. Global metabolite ratios were generated as an average of these sev en regional ratios. The Expanded Disability Status Scale (EDSS) was used for neu rologic evaluation. Results: The patients with AMN showed reduced global NAA/Cho (AMN 1.40 ±0.16 vs controls 1.75 ±0.34; p = 0.003) and global NAA/Cr (AMN 2.3 2 ±0.13 vs controls 2.62 ±0.43; p = 0.03). Regionally, NAA/Cho was lowered in the internal capsule(AMN 1.30 ±0.20 vs controls 1.69 ±0.37; p = 0.002) and inp arieto-occipital white matter (AMN 1.45 ±0.19 vs controls 1.78 ±0.55; p = 0.0 4). NAA/Cr was lowered in parieto-occipital white matter (AMN 2.34 ±0.31 vs co ntrols 2.83 ±0.71; p= 0.04). EDSS demonstrated an inverse association with glob al NAA/Cr (r = -0.65, p = 0.02) and NAA/Cr in centrum semiovale(r = -0.73, p = 0.006) and in parieto-occipital white matter (r= -0.64, p = 0.02). Cho/Cr was not significantly elevated.Conclusions: 1H-MR spectroscopic imaging is able to detect biochemical abnormalities sugge stive of axonal damage even in the brains of patients with pure adrenomyeloneuro pathy. The axonopathy is most prominent in internal capsule and parietooccipital white matter and may contribute to clinical disability.

Voxel Placement Precision for GABA-Edited Magnetic Resonance Spectroscopy

The purpose of the present study was to assess the reproducibility of voxel placement for GABA-edited MRS. GABA-edited MRS data were acquired in 13 healthy volunteers from (3 cm)3 voxel;and within the same session a second acquisition was independently prescribed. A three-dimensional voxel mask image was reconstructed in T1-image-space using the SVMask tool (in house software). Reproducibility of voxel placement was assessed using the Dice overlap coefficient, both within-subject and between-subject following co-registration of T1 images and transformation of voxel mask images to standard space. Within-subject overlap coefficients were 86% ± 5%. Between-subject overlap coefficients were 75% ± 10%. For the two voxel locations considered (occipital and sensorimotor), voxel overlap was very similar. Between-subject values are higher due to between-session effects, anatomical variability and volume mismatch in standard space. While surprisingly low in terms of volume overlap, the overlap coefficients correspond to acceptable linear displacements.

Label-Free Chemically and Molecularly Selective Magnetic Resonance Imaging

Biomedical imaging,especially molecular imaging,has been a driving force in scientific discovery,technological innovation,and precision medicine in the past two decades.While substantial advances and discoveries in chemical biology have been made to develop molecular imaging probes and tracers,translating these exogenous agents to clinical application in precision medicine is a major challenge.Among the clinically accepted imaging modalities,magnetic resonance imaging(MRI)and magnetic resonance spectroscopy(MRS)exemplify the most effective and robust biomedical imaging tools.Both MRI and MRS enable a broad range of chemical,biological diagnosis and characterization of many diseases and image-guided interventions.Using chemical,biological,and nuclear magnetic resonance properties of specific endogenous metabolites and native MRI contrast-enhancing biomolecules,label-free molecular and cellular imaging with MRI can be achieved in biomedical research and clinical management of patients with various diseases.This review article outlines the chemical and biological bases of several label-free chemically and molecularly selective MRI and MRS methods that have been applied in imaging biomarker discovery,preclinical investigation,and image-guided clinical management.Examples are provided to demonstrate strategies for using endogenous probes to report the molecular,metabolic,physiological,and functional events and processes in living systems,including patients.Future perspectives on label-free molecular MRI and its challenges as well as potential solutions,including the use of rational design and engineered approaches to develop chemical and biological imaging probes to facilitate or combine with label-free molecular MRI,are discussed.