BACKGROUND:Exosomes derived from mesenchymal stem cells play pivotal roles in cell communication and epigenetic regulation due to their low immunogenicity and targeted delivery effects,and have been clinically applied in the treatment of various diseases.OBJECTIVE:To review the isolation,purification,identification methods,and application progress of mesenchymal stem cell-derived exosomes,and to facilitate the development of large-scale preparation techniques and clinical translation of mesenchymal stem cell-derived exosomes.METHODS:The Chinese search terms"exosome,mesenchymal stem cells,isolation,purification,characterization,clinical application"and the English search terms"exosome,extracellular vesicles,mesenchymal stem cells,isolation,characterization,application"were used to search the literature published before September 2024 in CNKI,PubMed,and Web of Science databases.Articles with poor relevance to the topic,outdated,or duplicated content were excluded,and finally,109 articles were included for review.RESULTS AND CONCLUSION:(1)This paper reviews recent methods for isolating and purifying exosomes,comparing the characteristics of ultracentrifugation,ultrafiltration,size-exclusion chromatography,polymer precipitation,immunoaffinity,microfluidic methods,and other novel approaches based on their underlying principles.(2)Methods for identifying exosomes can be categorized into physical and biochemical analyses,characterizing exosomes based on their shape,size,and characteristic proteins.(3)Mesenchymal stem cell-derived exosomes have broad applications in multiple fields such as medical aesthetics,wound repair,and cancer treatment,due to their immune-regulatory properties and ability to cross biological barriers.(4)The clinical translation of exosomes faces challenges due to their complex structure,lack of universal isolation techniques,and poor stability,making it difficult to achieve in a short period of time.

BACKGROUND:Exosomes derived from mesenchymal stem cells play pivotal roles in cell communication and epigenetic regulation due to their low immunogenicity and targeted delivery effects,and have been clinically applied in the treatment of various diseases.OBJECTIVE:To review the isolation,purification,identification methods,and application progress of mesenchymal stem cell-derived exosomes,and to facilitate the development of large-scale preparation techniques and clinical translation of mesenchymal stem cell-derived exosomes.METHODS:The Chinese search terms"exosome,mesenchymal stem cells,isolation,purification,characterization,clinical application"and the English search terms"exosome,extracellular vesicles,mesenchymal stem cells,isolation,characterization,application"were used to search the literature published before September 2024 in CNKI,PubMed,and Web of Science databases.Articles with poor relevance to the topic,outdated,or duplicated content were excluded,and finally,109 articles were included for review.RESULTS AND CONCLUSION:(1)This paper reviews recent methods for isolating and purifying exosomes,comparing the characteristics of ultracentrifugation,ultrafiltration,size-exclusion chromatography,polymer precipitation,immunoaffinity,microfluidic methods,and other novel approaches based on their underlying principles.(2)Methods for identifying exosomes can be categorized into physical and biochemical analyses,characterizing exosomes based on their shape,size,and characteristic proteins.(3)Mesenchymal stem cell-derived exosomes have broad applications in multiple fields such as medical aesthetics,wound repair,and cancer treatment,due to their immune-regulatory properties and ability to cross biological barriers.(4)The clinical translation of exosomes faces challenges due to their complex structure,lack of universal isolation techniques,and poor stability,making it difficult to achieve in a short period of time.

Objective To investigate the influence of probiotics assisted with routine antibiotic regimens on the short-term clinical efficacy,mucosal barrier function and inflammatory response of patients with bacterial peritonitis secondary to liver cirrhosis.Methods 60 patients with bacterial peritonitis secondary to liver cirrhosis were chosen,and they were randomly divided into two groups according to the digital table,each group in 30 cases.The control group received routine antibiotic regimens alone,and the observation group were given probiotics on the basis of the control group.The short-term clinical efficacy,the levels of DAO,D-Lac and ET before and after treatment of the two groups were compared.Results The short-term effective rates of the control group and observation group were 70.00％,96.67％,respectively.The short-term effective rate of the observation group was significantly higher than that of control group(x2 =9.14,P ＜0.05).After treatment,the levels of DAO of the control group and observation group were (4.33 ± 0.79) U/mL,(2.19 ± 0.47) U/mL,respectively.The levels of D-Lac of the control group and observation group after treatment were (15.88 ± 1.95) U/mL,(8.57 ± 1.03) U/mL,respectively.The levels of DAO and D-Lac of the observation group after treatment were significantly lower than those of the control group and before treatment(t =2.78,3.06;3.44,3.78,3.61,4.10,all P ＜ 0.05).The levels of ET of the control group and observation group after treatment were (0.09 ± 0.02) EU/mL,(0.04 ± 0.01) EU/mL,respectively.The level of ET of the observation group after treatment was significantly lower than that of the control group and before treatment(t =2.49,3.01,3.46,all P ＜ 0.05).Conclusion Probiotics assisted with routine antibiotic regimens in the treatment of patients with bacterial peritonitis secondary to liver cirrhosis can effectively relieve the symptoms and signs,improve the mucosal barrier function and is helpful to reduce the inflammatory response.

The purpose of this study was prospectively to research the relationship between EEG power spectrum and anesthesia depth. Twenty-four patients,aged 20 to 50 years , ASA grade ,scheduled for selected surgical operations, were randomly divided into two groups:enflurane and isoflurane groups. Anesthesia was induced by thiopental 5 mg/kg and atracurium 6-7 mg/kg intravenously and maintained by inhalation anesthetics. After intubation patients were ventilated mechanically to maintain the level of PETCO2 between 4. 27 and 4. 93 kpa. NIBP,HR,SpO2 , ECG and EEG were recorded during anesthesia. According to TOF stimulation test intravenous atracurium 10-15 mg was given intermittently to maintain the ratio of T4/T1 less than 25%. Two channels EEG monitor was applied with the filtration range from 0 to 30 Hz Anesthesia level, adjusted at 0. 5,0. 8, 1. 0, 1. 3, 1. 5, 1. 3, 1. 0, 0.8 or 0. 5 MAC in sequence ,was maintained for 10 to 15 minutes before SEF (spectral edge frequency)and MPF (median power frequency) were recorded. NIBP decreased and HR increased with the inhaled agent concentration (IAC) level rising. The lowest BPs were 13. 1 /9. 33 kPa and 12. 9/8. 1kpa in both groups. There were negative remarkable correlations between either SEF or MPF and IAC in both groups (=- 0. 94 and -0. 82,P

The effects of different concentrations of enflurane and enflurane/nitrous oxide on EEG in 20 patients (ASA grade Ⅰ) were studied during elective surgery. They were divided randomly into two groups:enflurane (E) group (n=10) and enflurane/nitrous oxide (EN) group (n= 10). Anesthesia was induced by inhaling enflurane or enflurane/60% nitrous oxide. After intubation patients were venti lated mechanically to maintain P_(ET)CO_2 4.27—4.93 kPa, Two-leads EEG monitor was used during operation. 95% spectral edge frequency (SEF),MAP and HR were recorded in group E at 0.5,0.8,1.0,1.3 and 1.5 MAC, and in group EN at 0.8,1, 0,1.3,1.5,1.8 and 2.0 MAC. SEF decreased in linear manner,but MAP insignificantly changed as enflurane level increased. SEF was smaller in group E than that in group EN under the same additive MAC value, In raw EEG,patients in group E had spike wave at more than Ⅰ.0 MAC,but there was no spike wave in group EN. So enflurane/nitrous oxide anesthesia is more proper because nitrous oxide diminishs the undesirable effects of enflurane on brain during deeper anesthesia. The simple additive MAC value may not reflect the exact anesthesia level when nitrous oxide is used in combination, but SRF can do it.