Recently, there have been emerging interests in the area of microvesicles and exosome (MV/E) released from brain cells in relation to neurodegenerative diseases. However, only limited studies focused on MV/E released post-traumatic brain injury (TBI) as they highlight on the mechanistic roles of released proteins. This study sought to examine if CSF samples from severe TBI patients contain MV/E with unique protein contents. First, nanoparticle tracking analysis determined MV/E from TBI have a mode of 74-98 nm in diameter, while control CSF MV/E have a mode of 99-104 nm. Also, there are more MV/E were isolated from TBI CSF (27.8-33.6 × 10/mL) than from control CSF (13.1-18.5 × 10/mL). Transmission electron microscopy (TEM) visualization also confirmed characteristic MV/E morphology. Using targeted immunoblotting approach, we observed the presence of several known TBI biomarkers such as αII-spectrin breakdown products (BDPs), GFAP, and its BDPs and UCH-L1 in higher concentrations in MV/E from TBI CSF than their counterparts from control CSF. Furthermore, we found presynaptic terminal protein synaptophysin and known exosome marker Alix enriched in MV/E from human TBI CSF. In parallel, we conducted nRPLC-tandem mass spectrometry-based proteomic analysis of two control and two TBI CSF samples. Ninety-one proteins were identified with high confidence in MV/E from control CSF, whereas 466 proteins were identified in the counterpart from TBI CSF. MV/E isolated from human CSF contain cytoskeletal proteins, neurite-outgrowth related proteins, and synaptic proteins, extracellular matrix proteins, and complement protein C1q subcomponent subunit B. Taken together, following severe TBI, the injured human brain released increased number of extracellular microvesicles/exosomes (MV/E) into CSF. These TBI MV/E contain several known TBI biomarkers and previously undescribed brain protein markers. It is also possible that such TBI-specific MV/E might contain cell to cell communication factors related to both cell death signaling a well as neurodegeneration pathways.

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Acute spinal cord injury (SCI) is a devastating condition with many consequences and no known effective treatment. Although it is quite easy to diagnose traumatic SCI, the assessment of injury severity and projection of disease progression or recovery are often challenging, as no consensus biomarkers have been clearly identified. Here rats were subjected to experimental moderate or severe thoracic SCI. At 24h and 7d postinjury, spinal cord segment caudal to injury center versus sham samples was harvested and subjected to differential proteomic analysis. Cationic/anionic-exchange chromatography, followed by 1D polyacrylamide gel electrophoresis, was used to reduce protein complexity. A reverse phase liquid chromatography-tandem mass spectrometry proteomic platform was then utilized to identify proteome changes associated with SCI. Twenty-two and 22 proteins were up-regulated at 24 h and 7 day after SCI, respectively; whereas 19 and 16 proteins are down-regulated at 24 h and 7 day after SCI, respectively, when compared with sham control. A subset of 12 proteins were identified as candidate SCI biomarkers -TF (

In the USA, there are approximately 12,000 new cases of spinal cord injury (SCI) each year and some 1.2 million people living with paralysis due to SCI. Seven percent of them are paralyzed due to an accident or injury occurring while serving in the military. Here, we report a systematic study on protein biomarker candidates in a rat SCI model with either moderate or severe injury. Tissue, cerebrospinal fluid (CSF), and serum samples were obtained at 4 h, 24 h, and 7 days post-injury. The candidate biomarkers included axonal injury markers αII-spectrin breakdown products (SBDP150/145/120), neuronal cell body injury marker ubiquitin C-terminal hydrolase-L1 (UCH-L1), astrogliosis/astroglial injury markers S100 calcium-binding protein-β (S100β), glial fibrillary acidic protein (GFAP) and GFAP breakdown products (GBDPs), demyelination marker myelin basic protein (MBP), axonal injury marker phosphorylated neurofilament-H (pNF-H), and neuroinflammation marker interleukin-6 (IL-6). SBDP150/145, UCH-L1, GFAP, and S100β were found as acute biomarkers with significantly elevated levels within 24 h. GBDP44, GBDP38, and pNF-H are acute and subacute biomarkers that were found to have increased at 4 h, 24 h, and 7 days. MBP and SBDP120 were considered subacute biomarkers which were only detectable at 7 days post-injury. These results not only allow us to gain important insight into the patho-mechanisms of SCI but also showcase the possibility of using some of the protein biomarkers to track injury severity and disease progression and resolution. These biomarkers can potentially serve as tools that assist therapy development and clinical trials.