BACKGROUND: Due to the existence of the blood-brain barrier, macromolecular drugs cannot enter the brain tissue through the blood-brain barrier to exhibit their therapeutic effects. Therefore, many nervous system diseases and neurodegenerative diseases cannot be effectively treated. In recent years, studies have found that mesenchymal stem cells-derived exosomes are characterized by small volume and can be loaded with lipid, protein, nucleic acid and other signal substances, which can repair the tissue damage induced by ischemic or hemorrhagic stroke, Alzheimer's disease, epilepsy and spinal cord i njury. Mesenchymal stem cell exosomes have gradually become an important tool for the treatment of neurological diseases. OBJECTIVE: To analyze and summarize the effects of mesenchymal stem cells-derived exosomes on the treatment of nervous system diseases from both macroscopic and microscopic perspectives, and to present the problems and precautions in the basic research and clinical trials of exosomes. METHODS: “Exosomes, extracellular vesicles, MSCs, mesenchymal stem cells, neurodegenerative diseases” were used as the English search terms. The PubMed database was searched by computer, and the articles describing the characteristics and repairing effects of mesenchymal stem cells-derived exosomes were included. Irrelevant articles were excluded. Finally, 35 articles were included for further analysis. RESULTS AND CONCLUSION: Mesenchymal stem cells-derived exosomes have biological characteristics such as crossing the blood-brain barrier easily, carrying abundant signal substances, and playing important roles in animal disease models, such as anti-inflammation, promotion of neuronal growth, maintaining the number of neurons, and promotion of neurite remodeling. Meanwhile, modified exosomes can play a more effective tissue-repairing function than natural exosomes, which can be used as a specific molecular drug carrier for the treatment of specific neurological diseases.

ObjectiveTo investigate the changes and potential effects of differentially expressed microRNAs (miRNAs) in the development and progression of liver injury in a mouse model of autoimmune hepatitis (AIH) induced by concanavalin A (ConA). MethodsEight healthy male specific pathogen-free C57BL/6 mice were randomly divided into model group and control group, with four mice in each group. The mice in the model group were given tail vein injection of ConA 15 mg/kg, and those in the control group were given an equal volume of normal saline. All mice were sacrificed after 8 hours of modeling, Total RNA in liver tissue was extracted, gene microarray was used to screen out differentially expressed miRNAs, and target prediction and function analysis were performed for upregulated and downregulated miRNAs. The independent samples t-test was used for comparison of differentially expressed miRNAs between two groups. ResultsThe principal component analysis showed that the inter-group difference of the data extracted by gene microarray met the conditions for further analysis. Compared with the control group, the model group had 31 upregulated miRNAs and 18 downregulated miRNAs in mouse liver, which had a regulatory relationship with 959 target genes (601 upregulated genes and 358 downregulated genes). GO analysis showed that in the model group, the target genes of the upregulated miRNAs mainly had the molecular functions such as “DNA binding” (P=1.47×10-6), participated in the biological processes such as “transcription, DNA-templated” (P=2.36×10-7), and were mainly enriched in the cellular components such as “neuronal cell body” (P=5.99×10-6), while the target genes of the downregulated miRNAs had the molecular functions such as “RNA polymerase II proximal promoter sequence-specific DNA binding” (P=2.49×10-6), participated in the biological processes such as “regulation of transcription, DNA-templated” (P=1.64×10-11), and were mainly enriched in the cellular components such as “nucleoplasm” (P=4.30×10-10). KEGG pathway enrichment analysis showed that the target genes of the upregulated miRNAs were mainly enriched in “Endocytosis” (P=0.000 4), while the target genes of the downregulated miRNAs were mainly enriched in the “Hippo signaling pathway” (P=0.004), and the above functional analysis results were statistically significant (P＜0.05). ConclusionThere are differentially expressed miRNAs in the pathogenesis of AIH, and these differentially expressed miRNAs can provide new targets for the clinical treatment of AIH.

Objectives:To investigate the outcomes of cochlear implantation in Mandarin-speaking cochlear implant (CI) users with single-sided deafness (SSD).Methods:This study was a single-center prospective cohort study. Eleven Mandarin-speaking adult SSD patients who underwent CI implantation at Capital Medical University Beijing Tongren Hospital from August 2020 to October 2021 were recruited, including 6 males and 5 females, with the age ranging from 24 to 50 years old. In a sound field with 7 loudspeakers distributed at 180°, we measured root-mean-square error(RMSE)in SSD patients at the preoperative, 1-month, 3-month, 6-month, and 12-month after switch-on to assess the improvement of sound source localization. The Mandarin Speech Perception (MSP) was used in the sound field to test the speech reception threshold (SRT) of SSD patients under different signal-to-noise locations in a steady-state noise under conditions of CI off and CI on, to reflect the head shadow effect(S SSDN NH), binaural summation effect(S 0N 0) and squelch effect(S 0N SSD). The Tinnitus Handicap Inventory (THI) and the Visual Analogue Scale (VAS) were used to assess changes in tinnitus severity and tinnitus loudness in SSD patients at each time point. The Speech, Spatial and Qualities of Hearing Scale(SSQ) and the Nijmegen Cochlear Implantation Scale (NCIQ) were used to assess the subjective benefits of spatial speech perception and quality of life in SSD patients after cochlear implantation. SPSS 19.0 software was used for statistical analysis. Results:SSD patients showed a significant improvement in the poorer ear in hearing thresholds with CI-on compared with CI-off; The ability to localize the sound source was significantly improved, with statistically significant differences in RMSE at each follow-up time compared with the preoperative period ( P<0.05). In the S SSDN NH condition, which reflects the head shadow effect, the SRT in binaural hearing was significantly improved by 6.5 dB compared with unaided condition, and the difference was statistically significant ( t=6.25, P=0.001). However, there was no significant improvement in SRT between the binaural hearing condition and unaided conditions in the S 0N 0 and S 0N SSD conditions ( P>0.05). The total score of THI and three dimensions were significant decreased ( P<0.05). Tinnitus VAS scores were significantly lower in binaural hearing compared to the unaided condition ( P<0.001). The total score of SSQ, and the scores of speech and spatial dimensions were significant improved in binaural hearing compared to the unaided condition ( P<0.001). There was no statistical difference in NCIQ questionnaire scores between preoperative and postoperative ( P>0.05), and only the self-efficacy subscore showed a significant increase( Z=-2.497, P=0.013). Conclusion:CI could help Mandarin-speaking SSD patients restore binaural hearing to some extent, improve sound localization and speech recognition in noise. In addition, CI in SSD patients could suppress tinnitus, reduce the loudness of tinnitus, and improve subjective perceptions of spatial hearing and quality of life.