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CSF1R-related leukoencephalopathy is a rare white-matter encephalopathy characterized by motor and neuropsychiatric symptoms due to colony-stimulating factor 1 receptor (CSF1R) gene mutation. Few studies have investigated the intrinsic brain alternations of patients with CSF1R-related leukoencephalopathy. We aim to evaluate the structural and functional changes in those patients. Seven patients with CSF1R-related leukoencephalopathy and 15 age-matched healthy controls (HCs) underwent multimodal magnetic resonance imaging (MRI), including high-resolution T1-weighted imaging, T2-weighted fluid attenuated inversion recovery imaging, diffusion-weighted imaging, diffusion kurtosis imaging (DKI) and resting-state functional MRI. First, to detect structural alterations, the gray matter volumes were compared using voxel-based morphometry analyses. Second, DKI parametric maps were used to evaluate the white matter (WM) connectivity changes. Finally, we constructed a seed-based resting-state functional connectivity matrix based on 90 regions of interest and examined the functional network changes of CSF1R-related leukoencephalopathy. Unlike the HCs, patients with CSF1R-related leukoencephalopathy predominantly had morphological atrophy in the bilateral thalamus and left hippocampus. In addition, the abnormal diffusivity was mainly distributed in the splenium of the corpus callosum, periventricular regions, centrum semiovale, subcortical U-fibers and midline cortex structures. Moreover, the patients had significantly reduced functional connectivity between the bilateral caudate nucleus and their contralateral hippocampus. Therefore, in addition to hyperintensity on the T2-weighted images, CSF1R-related leukoencephalopathy also showed abnormal structural and functional alterations, including subcortical atrophy and reduced functional connectivity, as well as altered diffuse parameters in the WM and subcortical regions. These findings expand our understanding of the potential pathophysiologic mechanism behind this hereditary disease.

Electrical excitability by membrane depolarization is crucial for survival and maturation of newborn cells in the dentate gyrus of the hippocampus. However, traditional technology for membrane depolarization lacks temporal and spatial precision. Optogenetics can be used to activate channelrhodopsin-2 (ChR2), allowing cationic current to depolarize genetically targeted cells. In this study, we used ChR2-EGFP driven by doublecortin (DCX) to promote survival and maturation of newborn cells in the dentate gyrus after traumatic brain injury (TBI). C57BL/6 mice underwent lateral fluid percussion TBI. TBI mice were transfected with a lentivirus carrying the DCX-ChR2-EGFP gene. We observed that not only immature neurons but also type-2b intermediate progenitor (IPs) and neuroblasts expressed DCX-EGFP, indicating that DCX-expressing newborn cells could provide a long time window for electrical activity regulation. Quantitative results showed that the number of EGFP-expressing cells began to rise at 3 days after TBI and peaked at 9 days after TBI. By optical depolarization of DCX-EGFP-expressing cells between 3 and 12 days, we observed significantly improved cognitive deficits after TBI with enhanced survival and maturation of newborn cells in the dentate gyrus. We also investigated the role of optical depolarization in neural stem cells transfected with a lentivirus carrying the ChR2-DCX-EGFP gene in vitro. By administrating verapamil to block L-type calcium channels, we verified that the up-regulation of MAP2, NeuN, Neurog2, NeuroD1 and GluR2 in newborn cells was mediated by ChR2-elicted depolarization. By using β-catenin inhibitor Dkk1, we demonstrated that optical depolarization of DCX-EGFP-expressing cells facilitated survival and maturation probably through the Wnt/β-catenin signaling cascade.

The secretome of mesenchymal stem cell (MSC) offers a series of immunoregulatory properties and is regarded as an effective method of mitigating secondary neuroinflammation induced by traumatic brain injury (TBI). The secretome of adipose-derived MSCs (ASC-ST) was collected under hypoxia conditions. Proteomics data were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and concentrations of major components were tested. After the TBI caused by an electric cortical contusion impactor, rats were injected ASC-ST through caudal veins for 7 days. The neurological functional prognosis of TBI rats was significantly improved, and the vasogenic edema of brain tissues that was measured 14 days after TBI was relieved by ASC-ST, corresponding to brain water content levels. ASC-ST ameliorated TBI-induced neuroinflammatory environments that caused the edema, the apoptosis of the neural cells, and the nerve fiber damage by increasing the number of M2 phenotypes present while reducing the number of M1 phenotype microglia present. Furthermore, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) levels were reduced, whereas transforming growth factor-beta (TGF-β) and tumor necrosis factor-stimulated gene 6 protein (TSG-6) levels were increased after secretome treatment. Altogether, ASC-ST is capable of improving neural functioning by modulating TBI-induced neuroinflammation and its related secondary insults. ASC-ST may be one of the most promising candidates for regulating the secondary inflammatory reactions of central nervous systems for clinical use.

Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer-aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine.

How to promote neural repair following traumatic brain injury (TBI) has long been an intractable problem. Although acupuncture has been demonstrated to facilitate the neurological recovery, the underlying mechanism is elusive. Brain-derived neurotrophic factor (BDNF) exerts substantial protective effects for neurological disorders. In this study, we found that the level of BDNF and tropomyosin receptor kinase B (TrkB) was elevated spontaneously after TBI and reached up to the peak at 12 h. Nevertheless, this enhancement is quickly declined to the normal at 48 h. After combined stimulation at the acupoints of Baihui, Renzhong, Hegu, and Zusanli, we found that BDNF and TrkB were still significantly elevated at 168 h. We also observed that the downstream molecular p-Akt and p-Erk1/2 were significantly increased, suggesting that acupuncture could persistently activate the BDNF/TrkB pathway. To further verify that acupuncture improved recovery through activating BDNF/TrkB pathway, K252a (specific inhibitor of TrkB) was treated by injection stereotaxically into lateral ventricle. We observed that K252a could significantly prevent the acupuncture-induced amelioration of motor, sensation, cognition, and synaptic plasticity. These data indicated that acupuncture promoted the recovery of neurological impairment after TBI by activating BDNF/TrkB signaling pathway, providing new molecular mechanism for understanding traditional therapy of acupuncture.

Although previous research has demonstrated that traumatic brain injury (TBI) accelerates the proliferation of neural stem cells in dentate gyrus of the hippocampus, most of these newborn cells undergo apoptosis in a traumatic microenvironment. Thus, promoting the long-term survival of newborn cells during neurogenesis is a compelling goal for the treatment of TBI. In this study, we investigated whether mild hypothermia (MHT) therapy, which mitigates the multiple secondary injury cascades of TBI, enhances the survival of newborn cells. SD rats were subjected to unilateral fluid percussion injury and received MHT therapy for 4 h (33.5 °C). Bromodeoxyuridine (BrdU) was administered to label the mitotic cells. Spatial learning and memory were evaluated with the Morris water maze test. Brain sections were immunostained with antibodies against BrdU, DCX (a neuroblast marker) or NeuN (a mature neuron marker). The apoptosis levels in the dentate gyrus were examined with antibodies against the apoptotic proteins FAS, FASL, Bcl-2 and cleaved caspase 3. The results indicated that MHT could significantly prevent TBI-induced cognitive impairments. At 1 week after injury, the density of BrdU-immunoreactive cells significantly increased in both TBI and TBI + MHT rats. At 4 weeks after injury, the density of BrdU-positive cells further increased in TBI + MHT rats, whereas the density declined in the TBI rats. The density of DCX-positive cells in SGZ of the hippocampus at 1 week after injury in the TBI + MHT rats was significantly greater than in the TBI rats. Moreover, the density of NeuN-positive cells in the subgranular zone at 4 weeks after injury and in the granule cell layer at 7 weeks after injury was significantly increased in the TBI + MHT rats. The TBI + MHT rats displayed a lower level of apoptosis in the dentate gyrus compared with the TBI rats. These data indicate that TBI could only facilitate a burst of proliferation and short-term survival of newborn cells, whereas TBI + MHT could facilitate long-term survival and maturation of newborn cells through diminishing pro-apoptotic microenvironment. These results suggest that MHT-mediated neurogenesis may have an important therapeutic potential for the endogenous repair of TBI.

Both chemical and physical microenvironments appear to be important for lineage specification of umbilical cord mesenchymal stem cells (UCMSCs). However, physical factors such as the elastic modulus in traumatic brain injury (TBI) are seldom studied. Intracranial hypertension and cerebral edema after TBI may change the brain's physical microenvironment, which inhibits neural lineage specification of transplanted UCMSCs. The purpose of this study is to investigate the potential regulatory effect of mild hypothermia on the elastic modulus of the injured brain. First, we found that more UCMSCs grown on gels mimicking the elastic modulus of the brain (0.5 kPa) differentiated into neural cells, which were verified with the formation of branched cells and the expression of neural markers. Then, UCMSCs were transplanted into TBI rats, and we observed that mild hypothermia resulted in the differentiation of more neurons and astrocytes from transplanted UCMSCs. To demonstrate that more neural specification of UCMSCs was due to the regulation of the elastic modulus, we monitored intracranial pressure and cerebral edema. The results showed that mild hypothermia significantly reduced intracranial pressure and brain water content, indicating modulation of the elastic modulus by mild hypothermia. An examination with atomic force microscopy (AFM) in a cell injury model in vitro further verified hypothermia-regulated elastic modulus. In this study, we found a novel role of mild hypothermia in modulating the elastic modulus of the injured brain, resulting in the promotion of neural lineage specification of UCMSCs, which suggested that the combination of mild hypothermia had more advantages in cell-based therapy after TBI.

Although hypothermic-targeted temperature management (HTTM) holds great potential for the treatment of traumatic brain injury (TBI), translation of the efficacy of hypothermia from animal models to TBI patientshas no entire consistency. This study aimed to find an ideal time window model in experimental rats which was more in accordance with clinical practice through the delayed HTTM intervention. Sprague-Dawley rats were subjected to unilateral cortical contusion injury and received therapeutic hypothermia at 15mins, 2 h, 4 h respectively after TBI. The neurological function was evaluated with the modified neurological severity score and Morris water maze test. The brain edema and morphological changes were measured with the water content and H&E staining. Brain sections were immunostained with antibodies against DCX (a neuroblast marker) and GFAP (an astrocyte marker). The apoptosis levels in the ipsilateral hippocampi and cortex were examined with antibodies against the apoptotic proteins Bcl-2, Bax, and cleaved caspase-3 by the immunofluorescence and western blotting. The results indicated that each hypothermia therapy group could improve neurobehavioral and cognitive function, alleviate brain edema and reduce inflammation. Furthermore, we observed that therapeutic hypothermia increased DCX expression, decreased GFAP expression, upregulated Bcl-2 expression and downregulated Bax and cleaved Caspase-3 expression. The above results suggested that HTTM at 2h or even at 4h post-injury revealed beneficial brain protection similarly, despite the best effect at 15min post-injury. These findings may provide relatively ideal time window models, further making the following experimental results more credible and persuasive.

Background and purpose Hyperekplexia (HPX), a rare neurogenetic disorder, is classically characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli and followed by a shortly general stiffness. Glycine receptor alpha 1 (GLRA1) is the major pathogenic gene of the disease. We described the clinical manifestations of genetically confirmed HPX patients and made a literature review of GLRA1-related HPX to improve the early recognition and prompt the management of the disorder. Methods Extensive clinical evaluations were analyzed in 4 Chinese HPX patients from two unrelated families. Next generation sequencing was conducted in the probands. Sanger sequence and segregation analysis were applied to confirm the findings. Results All four patients including 3 males and 1 female presented with excessive startle reflex, a cautious gait and recurrent falls. Moreover, startle episodes were dramatically improved with the treatment of clonazepam in all cases. Exome sequencing revealed 2 homozygous GLRA1 mutations in the patients. The mutation c.1286T>A p.I429N has been previously reported, while c.754delC p.L252* is novel. Conclusions HPX is a treatable disease, and clonazepam is the drug of choice. By studying and reviewing the disorder, we summarized the phenotype, expanded the genotype spectrum, and discussed the possible pathogenic mechanisms to enhance the understanding and recognition of the disease. Early awareness of the disease is crucial to the prompt and proper administration, as well as the genetic counseling.