Objective To investigate the protective effect and underlying mechanism of human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exo) on renal ischemia-reperfusion injury (IRI). Methods hucMSC-Exos were isolated and characterized. A mouse renal IRI model was established and the animals were divided into Sham, IRI, IRI+hucMSC-Exo, IRI+hucMSC-Exo+JY-2 and Sham+JY-2 groups. Serum creatinine (Scr) and blood urea nitrogen (BUN) were measured. Hematoxylin-eosin (HE) staining was used to evaluate renal histopathology. Enzyme-linked immune absorbent assay was performed to determine serum interleukin (IL)-1β and IL-18 levels. Western blotting was used to detect the expression of activating transcription factor 3 (ATF3), Toll-like receptor 4 (TLR4), nuclear factor (NF)-κB, NOD-like receptor protein 3 (NLRP3), cysteineyl aspartate specific proteinase (Caspase)-1 p20 and Gasdermin D(GSDMD). Real-time fluorescent quantitative polymerase chain reaction was employed to measure ATF3, TLR4 and NF-κB messenger RNA (mRNA). Immunohistochemistry was conducted to examine NLRP3, Caspase-1 p20 and GSDMD. An in vitro hypoxia/reoxygenation (H/R) model was established in HK-2 cells and divided into Control, H/R, H/R+hucMSC-Exo, H/R+hucMSC-Exo+JY-2 and Control+JY-2 groups. Western blotting was used to detect the expression of ATF3, TLR4 and NF-κB. Real-time fluorescent quantitative polymerase chain reaction was used to measure NLRP3, GSDMD and Caspase-1 mRNA. Results HucMSC-Exos were successfully isolated and identified. Compared with the Sham group, the IRI group exhibited elevated Scr and BUN, higher tubular injury scores, increased protein expression levels of ATF3, TLR4, NF-κB p65, NLRP3, Caspase-1 p20 and GSDMD, and raised mRNA expression levels of ATF3, TLR4, NF-κB. Compared with the IRI group, the IRI+hucMSC-Exo group showed decreased Scr and BUN, lower tubular injury scores, up-regulated ATF3 protein and mRNA, down-regulated TLR4, NF-κB p65, NLRP3, Caspase-1 p20 and GSDMD protein, and declined TLR4 and NF-κB mRNA. Compared with the IRI+hucMSC-Exo group, the IRI+hucMSC-Exo+JY-2 group exhibited increased Scr and BUN levels, elevated renal tubular injury scores, decreased ATF3 protein expression levels, elevated protein expression levels of TLR4, NF-κB p65, NLRP3, Caspase-1 p20, and GSDMD, decreased ATF3 mRNA expression levels, and elevated mRNA expression levels of TLR4 and NF-κB. (all P < 0.05). Compared with the Control group, the expression levels of ATF3, TLR4 and NF-κB p65 proteins were increased in the H/R group, and the expression levels of NLRP3, Caspase-1 and GSDMD mRNA were increased. Compared with the H/R group, the expression level of ATF3 protein was increased, the expression levels of TLR4 and NF-κB p65 proteins were decreased, and the expression levels of NLRP3, Caspase-1 and GSDMD mRNA were decreased in the H/R+hucMSC-Exo group. Compared with the H/R+hucMSC-Exo group, the expression level of ATF3 protein was decreased, the expression levels of TLR4 and NF-κB p65 proteins were increased, and the expression levels of NLRP3, Caspase-1 and GSDMD mRNA were increased in the H/R+hucMSC-Exo+JY-2 group (all P < 0.05). Conclusions HucMSC-Exos alleviate renal IRI by up-regulating ATF3, thereby negatively regulating the TLR4/NF-κB signaling pathway and subsequently inhibiting pyroptosis.

BACKGROUND:Human umbilical cord mesenchymal stem cell-derived exosomes are involved in multiple injury repair processes,and the effects and the specific mechanisms of renal ischemia/reperfusion injury have not been fully elucidated.OBJECTIVE:To investigate the molecular mechanism of human umbilical cord mesenchymal stem cell-derived exosomes in the treatment of renal ischemia/reperfusion injury.METHODS:(1) Human umbilical cord mesenchymal stem cells were cultured and exosomes were obtained and identified using an exosome extraction kit.(2) The distribution of exosomes in the kidney of mice with renal ischemia/reperfusion injury was examined by intravital fluorescence imaging.(3) Thirty C57/BL6 male mice were divided into five groups according to the random number table method:sham operation group,renal ischemia/reperfusion group,sham operation group+Compound C group,renal ischemia/reperfusion+exosome group (exosome group),and renal ischemia/reperfusion+exosome+Compound C group (exosome+Compound C group),with 6 mice in each group.Except the sham operation group,bilateral renal pedicles were clamped for 45 minutes and a mouse model of renal ischemia/reperfusion injury was established after 24 hours of reperfusion.In sham operation+Compound C group and exosome+Compound C group,AMPK inhibitor Compound C was intraperitoneally injected 30 minutes before model establishment.In the exosome group and exosome+Copmpound C group,exosomes were injected through the tail vein 15 minutes before renal pedicle clipping.The levels of serum creatinine and urea nitrogen,interleukin 6,and tumor necrosis factor α in renal tissue,and the expression of apoptosis-related factors in renal tissue were detected after 24 hours of reperfusion in each group.RESULTS AND CONCLUSION:(1) Human umbilical cord mesenchymal stem cell exosomes had the typical tea tray morphology,with the diameter distribution in the range of 40-160 nm,and expressed the specific marker membrane protein of exosome surface.(2) Murine kidneys after renal ischemia/reperfusion injury were more likely to gather human umbilical cord mesenchymal stem cell exosomes compared with the sham operation group.(3) Exosome pretreatment reduced renal injury and the level of renal cell apoptosis in mice treated with renal ischemia/reperfusion injury.Moreover,this protective effect could be reversed by AMPK inhibitors.These findings verify that human umbilical cord mesenchymal stem cell-derived exosomes exerting a protective effect on renal ischemia/reperfusion injury may be related to the activation of the AMPK/YAP1 pathway to antiapoptosis.

Objective To explore the effects and mechanisms of human umbilical cord mesenchymal stem cell (HUC-MSC)-derived exosomes (Exo) pretreated with Huangkui capsules on renal ischemia-reperfusion injury (IRI). Methods HUC-MSCs were cultured in media containing different concentrations of Huangkui capsules for 24 hours to determine cell viability and select an appropriate concentration for subsequent experiments. HUC-MSCs were pretreated with 50 μg/mL Huangkui capsules for 24 hours, and Exo were extracted using an exosome extraction kit. The morphology was observed under a transmission electron microscope, particle size was measured by nanoparticle tracking analysis, and the expression of exosomal membrane surface marker proteins was detected by Western blot. Human renal tubular epithelial cells (HK-2 cells) were randomly divided into hypoxia/reoxygenation group (M group), hypoxia/reoxygenation + Exo group (E group), and hypoxia/reoxygenation + Huangkui capsules pretreated Exo group (H group). Western blotting was used to measure the expression of endoplasmic reticulum stress (ERS)-related proteins, and real-time fluorescent quantitative reverse transcription polymerase chain reaction was used to measure the expression of ERS-related gene messenger RNA (mRNA). Mice were randomly divided into sham operation group (Sham group), ischemia-reperfusion group (I/R group), ischemia-reperfusion + Exo group (E group), and ischemia-reperfusion + Huangkui capsules pretreated Exo group (H group). Renal histological assessment, serum creatinine (Scr), blood urea nitrogen (BUN) measurement and inflammatory factor detection were performed 24 hours later. Results Both Exo and Huangkui capsules prereated Exo had a bilayer membrane structure and a cup-shaped morphology; their average particle sizes were 116.8 nm and 81.3 nm, respectively. Both expressed CD9, CD63, TSG101. Compared with the M group, the E group had decreased relative expression of transcription factor 6 (ATF6) and protein kinase R-like endoplasmic reticulum kinase (PERK) proteins, increased mRNA relative expression, increased relative expression of C/EBP homologous protein (CHOP) protein, and decreased mRNA relative expression. Compared with the E group, the H group had decreased relative expression of ATF6, PERK, CHOP proteins, and decreased mRNA relative expression of ATF6 and PERK (all P<0.05). Animal experimental results showed that compared with the Sham group, the I/R group had increased renal tubular injury scores, Scr, BUN, interleukin (IL)-1β, IL-10, IL-18, tumor necrosis factor (TNF)-α levels. Compared with the I/R group, the E and H groups had decreased renal tubular injury scores and Scr, BUN, IL-1β, IL-10, IL-18, TNF-α levels. Compared with the E group, the H group had decreased renal tubular injury scores and Scr, BUN, IL-1β, IL-10, IL-18, TNF-α levels (all P<0.05). Conclusions Huangkui capsules pretreatment HUC-MSC-derived Exo may alleviate renal IRI by inhibiting ERS.

In the field of organ donation and transplantation, the determination of death faces the dilemma of the separation between medical standards and social cognition, which may hinder medical practice and lead to controversial legal evaluations. Establishing brain death criteria through the "hard law" model is the path currently adopted by many countries. However, this approach has limitations, such as the attribution of the right to define death in the law, the conflict between the technological iteration of brain death criteria and legal stability, and the neglect of the social construction of the concept of death. Based on the theory of gradual social engineering and social systems theory, establishing brain death criteria through the "soft law" model has both scientific adaptability and governance flexibility, and is conducive to cultivating social consensus on brain death criteria. In terms of implementation, it is essential to focus on the high-level positioning of the "soft law" formulation entities for brain death criteria, the professionalization of the implementation entities, the publicization of the formulation process, and the institutionalization of risk communication strategies. At the same time, it is necessary to strengthen the informed consent of close relatives and design a dispute resolution mechanism for misjudgments of brain death to guard against potential improper risks.

BACKGROUND:Human umbilical cord mesenchymal stem cell-derived exosomes are involved in multiple injury repair processes,and the effects and the specific mechanisms of renal ischemia/reperfusion injury have not been fully elucidated.OBJECTIVE:To investigate the molecular mechanism of human umbilical cord mesenchymal stem cell-derived exosomes in the treatment of renal ischemia/reperfusion injury.METHODS:(1) Human umbilical cord mesenchymal stem cells were cultured and exosomes were obtained and identified using an exosome extraction kit.(2) The distribution of exosomes in the kidney of mice with renal ischemia/reperfusion injury was examined by intravital fluorescence imaging.(3) Thirty C57/BL6 male mice were divided into five groups according to the random number table method:sham operation group,renal ischemia/reperfusion group,sham operation group+Compound C group,renal ischemia/reperfusion+exosome group (exosome group),and renal ischemia/reperfusion+exosome+Compound C group (exosome+Compound C group),with 6 mice in each group.Except the sham operation group,bilateral renal pedicles were clamped for 45 minutes and a mouse model of renal ischemia/reperfusion injury was established after 24 hours of reperfusion.In sham operation+Compound C group and exosome+Compound C group,AMPK inhibitor Compound C was intraperitoneally injected 30 minutes before model establishment.In the exosome group and exosome+Copmpound C group,exosomes were injected through the tail vein 15 minutes before renal pedicle clipping.The levels of serum creatinine and urea nitrogen,interleukin 6,and tumor necrosis factor α in renal tissue,and the expression of apoptosis-related factors in renal tissue were detected after 24 hours of reperfusion in each group.RESULTS AND CONCLUSION:(1) Human umbilical cord mesenchymal stem cell exosomes had the typical tea tray morphology,with the diameter distribution in the range of 40-160 nm,and expressed the specific marker membrane protein of exosome surface.(2) Murine kidneys after renal ischemia/reperfusion injury were more likely to gather human umbilical cord mesenchymal stem cell exosomes compared with the sham operation group.(3) Exosome pretreatment reduced renal injury and the level of renal cell apoptosis in mice treated with renal ischemia/reperfusion injury.Moreover,this protective effect could be reversed by AMPK inhibitors.These findings verify that human umbilical cord mesenchymal stem cell-derived exosomes exerting a protective effect on renal ischemia/reperfusion injury may be related to the activation of the AMPK/YAP1 pathway to antiapoptosis.

Objective To observe the efficacy of gray-scale ultrasound-based radiomics for differentiating peripheral pulmonary adenocarcinoma and squamous cell carcinoma.Methods Data of 88 patients with single peripheral lung adenocarcinoma and 58 patients with single peripheral lung squamous cell carcinoma proved pathologically with puncture biopsy and clearly visualized with lung ultrasound were retrospectively analyzed.The patients were divided into training set(n=103)and test set(n=43)at the ratio of 7:3.Based on gray-scale ultrasound of training set,radiomics features associated with differential diagnosis of peripheral lung adenocarcinoma and lung squamous cell carcinoma were extracted and screened.Using 4 different classifiers,including support vector machine(SVM),linear discriminant analysis(LDA),logistic regression(LR)and the least absolute shrinkage and selection operator combined with logistic regression(LASSO-LR),4 corresponding radiomics models were obtained,and the relative best models were selected according to their performances under 10-fold cross validation.The receiver operating characteristic curves were drawn,the areas under the curve(AUC)were calculated to evaluate the differentiating efficacy of each model,and DeLong test was used for the comparison.The differentiating accuracy of models were obtained under the best cutoff value with the maximum Youden index.Results The AUC of SVM,LDA,LR and LASSO-LR radiomics models for differentiating peripheral lung adenocarcinoma and lung squamous carcinoma in test set was 0.864,0.867,0.880 and 0.844,respectively,and no significant difference was found among 4 models(all P＞0.05).Under the best cutoff value of each model,the corresponding accuracy of SVM,LDA,LR and LASSO-LR radiomics models for differentiating peripheral lung adenocarcinoma and lung squamous cell carcinoma was 86.05％,83.72％,88.37％and 86.05％,respectively.Conclusion Radiomics models based on gray-scale ultrasound could be used to differentiate peripheral lung adenocarcinoma and lung squamous cell carcinoma.

Objective:To investigate the clinical characteristics of psoriasis and status quo of medical care for patients in county areas of China.Methods:This study was a cross-sectional investigation. Based on the “Qianxian Wuyin” Project (a national project for upgrating ability for psoriasis care at county level), an online questionnaire survey was conducted in the dermatology departments of 459 county hospitals in 404 pilot administrative counties across China from February to June 2023. The questionnaire included demographic information of patients (gender, ethnicity, age, place of residence, education, marital status), and clinical characteristics of psoriasis (disease course, type, comorbidities, body surface area (BSA) and previous treatment. The Dermatology Life Quality Index (DLQI) and Psoriasis Area and Severity Index (PASI) were applied for assessing the quality of life and disease severity, and completed by patients or guardian and doctors, respectively.Results:A total of 16 935 patients completed the questionnaire. The age of patients was 1-102(44.17±11.58)years, and 71.0% (12 036/16 935) were 30-59 years old. The ratio of male to female was 2.21∶1; 24.3%(4 117/16 935) of patients had high school education; there were 9 940 patients(58.7%) with previous or current smoking and/or alcohol use; 42.8%(7 218/16 855) of patients had a disease course of 1-5 years. There were 15 630 patients(92.3%) with DLQI≥10, 8 346 patients(49.7%) with PASI≥10, 15 017 patients(89.2%) with BSA≥10%. The plaque type was the most common disease type ( n=14 965, 88.7%), and spotting type ranked the second ( n=1 141, 6.8%). The most common initial site was the trunk ( n=12 309, 72.9%). Among the comorbidities, hypertension was the most common one ( n=1 681, 10.0%). There were 7 650 reports of treatment response to conventional topical drug therapy and 3 112 reports of treatment response to systemic drug therapy, with 6 269 (81.9%) and 2 493 (80.1%) reporting poor or no response, respectively. Conclusions:The survey shows that in the county areas of China, the majority of psoriasis patients are severe patients with short course of disease, plaque type is the most common type, and hypertension is the most common comorbidity; and the conventional treatment is less effective for most patients.

Objective:To evaluate the role of nuclear factor E2-related factor 2 (Nrf2)/heme oxidase-1 (HO-1) in reduction of renal ischemia-reperfusion (I/R) injury by the human umbilical cord mesenchymal stem cells (hucMSCs)-derived exosomes (hucMSCs-exo) in mice.Methods:The hucMSCs were cultured, and exosomes were extracted and identified by transmission electron microscopy, nanoparticle tracking analysis and Western blot. Thirty-six male SPF-grade C57BL/6 mice, weighing 20-25 g, were used. Thirty mice were selected and divided into 5 groups ( n=6 each) by a random number table method: sham operation group (Sham group), sham operation + Nrf2 inhibitor ML385 group (Sham + ML385 group), renal I/R group (I/R group), renal I/R + exosome group (I/R+ EXO group), and renal I/R + exosome + Nrf2 inhibitor ML385 group (I/R+ EXO+ ML385 group). A model of renal I/R injury was prepared by clamping the bilateral renal pedicles for 45 min followed by perfusion in anesthetized animals. ML385 30 mg/kg was intraperitoneally injected at 45 min before preparing the model in Sham+ ML385 group and I/R+ EXO+ ML385 group, and hucMSCs-exo 100 μg was injected via the tail vein at 15 min before reperfusion in I/R+ EXO group and I/R+ EXO+ ML385 group. Serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations were detected at 24 h of reperfusion. The renal tissues were obtained for examination of the pathological changes and for determination of contents of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and malondialdehyde (MDA), superoxide dismutase (SOD) activity and reactive oxygen species (ROS) levels and expression of Nrf2 and HO-1 protein and mRNA (by Western blot and quantitative real-time polymerase chain reaction). The left 6 mice were allocated to sham operation group (Sham-IM group, n=3) and renal I/R group (I/R-IM group, n=3) by a random number table method for VISQUE in living imaging observation. Results:The exosomes showed a typical cup-shaped morphology with a transmission electron microscope, the nanoparticles tracked and analyzed the average diameter of the exosome, with an average diameter of 96.7 nm, and the positive expression of surface markers CD9, CD63 and TSG101 was detected using Western blot. The renal fluorescence intensity value was significantly increased in I/R-IM group as compared with Sham-IM group ( P<0.05). Compared with Sham group, the serum BUN and Cr concentrations were significantly increased, the contents of IL-6, TNF-α and MDA and ROS levels were increased, the activity of SOD was decreased, the expression of Nrf2 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the pathological changes of renal tissues were aggravated in I/R group, and no significant change was found in serum BUN and Cr concentrations in Sham+ ML385 group ( P>0.05). Compared with I/R group, the serum BUN and Cr concentrations were significantly decreased, the contents of IL-6, TNF-α and MDA and ROS levels were decreased, the activity of SOD was increased, the expression of Nrf2 and HO-1 protein and mRNA was up-regulated ( P<0.05), and the pathological changes of renal tissues were significantly attenuated in I/R+ EXO group. Compared with I/R+ EXO group, the serum BUN and Cr concentrations were significantly increased, the contents of IL-6, TNF-α and MDA and ROS levels were increased, the activity of SOD was decreased, the expression of Nrf2 and HO-1 protein and mRNA was down-regulated ( P<0.05), and the pathological changes of renal tissues were aggravated in I/R+ EXO+ ML385 group. Conclusions:The mechanism by which hucMSCs-exo reduces renal I/R injury may be related to activation of the Nrf2/HO-1 signaling pathway in mice.

BACKGROUND:The angle of screw placement in anterior cervical discectomy and fusion plays a crucial role in determining the stability of the internal fixation system. OBJECTIVE:To predict the impact of different screw placement angles on the stress experienced by the internal fixation system in anterior cervical discectomy and fusion utilizing finite element analysis,with the ultimate goal of identifying the optimal screw placement angle. METHODS:A three-dimensional reconstruction method was employed to establish a mechanical model of the cervical spine,enabling the simulation of three distinct working conditions:scoliosis,uprightness,and forward flexion.In SolidWorks 2017,the anterior cervical plate and screw models were built according to different placement angles of the screws,with a as the inward offset,b as the ideal position,c as the outward offset,d as the downward offset,and e as the upward offset.The stress distribution of internal fixation system at different screw placement angles was observed,and the stress and displacement were recorded. RESULTS AND CONCLUSION:(1)By constructing a finite element model of the entire cervical spine and incorporating an anterior titanium plate,it was found that the biomechanical changes in the spine did not significantly differ based on the various angles of screw insertion on the titanium plate under the same working conditions.(2)However,microscopic analysis revealed that the outward offset(c)screw position exhibited the most effective resistance against side bending,while the downward offset(d)screw demonstrated optimal load-bearing capacity in the upright condition.Additionally,the outward deviation(c)screw displayed superior anti-bending effects in the reverse buckling condition.(3)The fixation effect of the internal fixation device remained relatively stable across different motion conditions.Although there was a 10％variation in the internal fixation effect under the three working conditions when the screw was placed inward,outward,downward,or upward,the displacement changes were minimal.These findings suggest that the requirements of load bearing,bending resistance,and flexion resistance could be simultaneously met without a specific optimal screw location in clinical practice.(4)The placement direction of titanium plate screw in anterior cervical disc-resection and fusion has little effect on the mechanical stability of the cervical spine.The screw angles in different directions have little influence on the stability of the internal fixation device in the lateral,upright,and forward flexion movements of the cervical spine.There is no need to pursue the direction of screw placement in clinical operations.