ABSTRACT
Objective:To screen plasma exosomal protein molecular markers in patients with spinal cord injury (SCI) by applying Label-Free quantification and bioinformatics analysis.Methods:Fifty plasma specimens from the First Affiliated Hospital of Nanjing Medical University (from January 2021 to June 2022) were collected from SCI patients and healthy people, respectively. Plasma exosomes were isolated using ultracentrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis and western blot. Plasma exosomal differentially expressed proteins (DEPs) were analyzed using Label-Free quantitative proteomics, and DEPs were characterized, annotated, and enriched based on Gene Ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) databases. The screened DEPs were validated by western blot and enzyme linked immunosorbent assay (ELISA) using plasma exosomal specimens.Results:According to the spinal cord injury classification of the American Spinal Injury Association, 14 cases were grade A, 19 cases were grade B, 12 cases were grade C, and 5 cases were grade D. Plasma exosomes of SCI patients and control groups showed typical cup-like morphology, with diameters mainly ranging from 30-200 nm. A total of 493 exosomal proteins were identified by Label-Free quantification, and 126 proteins were screened for differential expression, of which 38 were up-regulated and 88 were down-regulated. GO annotation revealed that DEPs were mainly involved in functions such as protein activation cascade, complement activation and immune response. KEGG pathway analysis revealed that DEPs were involved in biological pathways such as complement and coagulation cascade reactions, proteasome and neurodegenerative disease pathways. Two candidate proteins, APOB and S100A9, were initially screened based on quantitative results from proteomics and bioinformatics analyses. Western blot results showed that the relative expression of S100A9 protein in plasma exosomes of 30 SCI patients (1.62±0.19) was elevated compared with that of 30 control groups (0.86±0.24), and the difference was statistically significant ( t=8.55, P<0.001), while the relative expression of APOB protein (1.06±0.13 and 1.02±0.23) were not statistically significant ( t=0.46, P=0.653). The results of ELISA analysis showed that the expression of S100A9 in plasma exosomes of patients with different degrees of SCI (grade A 197.7±11.7 pg/ml, grade B 151.7±15.2 pg/ml, grade C 136.3±14.7 pg/ml) had statistical significance ( F=69.94, P<0.001), the higher the severity of SCI, the higher the expression of S100A9 in plasma exosomes (A vs. B, q=13.11, P<0.001; A vs. C, q=15.66, P<0.001; B vs. C, q=4.19, P=0.005). Conclusion:S100A9 is a potentially valid plasma exosomal molecular marker for assessing the severity of SCI.
ABSTRACT
Osteoporotic thoracolumbar fracture in the elderly will seriously reduce their quality of life and life expectancy. For osteoporotic thoracolumbar fracture in the elderly, spinal reconstruction is necessary, which should comprehensively consider factors such as the physical condition, fracture type, clinical characteristics and osteoporosis degree. While there lacks relevant clinical norms or guidelines on selection of spinal reconstruction strategies. In order to standardize the concept of spinal reconstruction for osteoporotic thoracolumbar fracture in the elderly, based on the principles of scientificity, practicality and progressiveness, the authors formulated the Clinical guideline for spinal reconstruction of osteoporotic thoracolumbar fracture in elderly patients ( version 2022), in which suggestions based on evidence of evidence-based medicine were put forward upon 10 important issues related to the fracture classification, non-operative treatment strategies and surgical treatment strategies in spinal reconstruction after osteoporosis thoracolumbar fracture in the elderly, hoping to provide a reference for clinical treatment.