OBJECTIVE To investigate the impact of vesicular stomatitis virus envelope glycopro-tein-G(VSV-G)modification on the mucosal immune efficacy of antigen-loaded engineered exosome vaccines.METHODS In vitro experiments:Dendritic cells(DCs)were divided into three groups:cell-control(treated with culture medium),receptor binding domain(RBD)(transfected with plasmid RBD),and RBD+VSV-G(co-transfected with plasmids RBD and VSV-G).Expression levels of RBD and VSV-G were assessed using Western blotting,flow cytometry,and immunofluorescence.Exosomes were extracted via ultracentrifugation,whose morphology,size distribution,and marker proteins were analyzed using transmission electron microscopy,nanoparticle tracking analysis,and Western blotting that confirmed the expressions of RBD and VSV-G in the exosomes.In vivo experiments:① Female BALB/c mice were divided into the control group Mock exosomes(Mock-Exo)(derived from the supernatant of cell-control),RBD decorated exosomes(RBD-Exo)(derived from the RBD cell supernatant),and RBD and VSV-G decorated exosomes(RBD+VSV-G-Exo)(derived from RBD+VSV-G cell supernatant).Follow-ing intranasal immunization with the respective vaccines,the nasal retention effects were evaluated using in vivo imaging.Flow cytometry was used to assess the ability to recruit immune cells to the nasal tissue.Serum RBD-specific immunoglobulin G(IgG)and mucosal immunoglobulin A(IgA)(bronchoal-veolar lavage fluid/nasal wash)were quantified at 7 and 21 d post-immunization by enzyme-linked immuno-sorbent assay.Body weight changes were monitored and key serum biochemical parameters along with histopathological damage to major organs were analyzed following immunization.② Female BALB/c mice were divided into the Mock-Exo group(intranasally inoculated with Mock-Exo),RBD+VSV-G-Exo group(intranasally inoculated with RBD+VSV-G-Exo),and RBD+VSV-G-Exo(im)group(intramus-cularly injected with RBD+VSV-G-Exo).RESULTS In vitro experiments:RBD and VSV-G were successfully expressed in cells,with positive rates of RBD+and VSV-G+cells at 64.4%and 31.2%,respectively.The extracted exosomes exhibited regular morphology and qualified purity,with a particle size of approximately 138 nm and successfully loaded RBD and VSV-G proteins.In vivo experiments:Compared to Mock-Exo and RBD-Exo,RBD+VSV-G-Exo prolonged nasal retention time to 96 h and markedly increased the numbers of CD49B+natural killer cells,CD11c+dendritic cells,and F4/80+macrophages in nasal tissues.RBD+VSV-G-Exo induced robust RBD-specific immune responses,with serum IgG titers,BALF IgA titers,and nasal wash IgA titers reaching 1∶5 215,1∶2 560,1∶1 114,respec-tively.In contrast,no RBD-specific IgA antibody titers were detected in the BALF and nasal wash of mice treated with RBD+VSV-G-Exo(im).Mice showed stable body weight gain during 30 d post-immu-nization.Major serum biochemical indices were within normal reference ranges,and no obvious patho-logical changes were observed in major organs or olfactory bulbs 7 d after immunization.CONCLU-SION VSV-G modification extends the retention time of engineered exosome vaccines in nasal tissues,enhance their ability to recruit immune cells,and induce a high-level antigen-specific respiratory mucosal immune response.

BACKGROUND:The pathogenesis of patellofemoral pain is complex,and poor movement patterns and incorrect muscle activation patterns have been suggested to increase patellofemoral joint stress and cause injury,but the results of current studies are not uniform.Current biomechanical studies of step-down test in patients with patellofemoral pain have focused on kinematic characteristics,and there is a lack of research on surface electromyographic characteristics.In addition,there are no studies that analyze the differences in biomechanical performance between the healthy and affected sides of patellofemoral pain patients compared with healthy subjects during the downward step test.OBJECTIVE:To investigate the kinematic and surface electromyographic characteristics of patients with patellofemoral pain during bilateral lower extremity step-downs.METHODS:Twenty-one men with patellofemoral pain and 21 healthy men were recruited,and both groups of subjects underwent a step-down test.Kinematic,kinetic and surface electromyographic data were synchronously collected using a three-dimensional dynamic capture system,a force platform and a surface electromyographic tester.RESULTS AND CONCLUSION:(1)Kinematics:Compared with the healthy control group,the affected and healthy sides of the patellofemoral pain group showed a smaller hip flexion angle(P=0.005,P=0.011),a larger hip internal rotation angle(P=0.033,P=0.039),and a larger knee valgus angle(P=0.001,P=0.001),and the affected side of the patellofemoral pain group exhibited a larger hip internal rotation angle(P=0.013),a smaller knee flexion angle(P=0.043),and a smaller ankle dorsiflexion angle(P=0.002);and compared with the healthy side,the affected side exhibited a smaller ankle dorsiflexion angle(P=0.002).(2)Surface electromyography:Compared with the healthy control group,the patellofemoral pain group showed reduced activation of the vastus medialis oblique(P=0.002),reduced activation of the gluteus medius(P=0.015),and a decreased vastus medialis oblique/vastus lateralis ratio(P=0.010)on the affected side;and compared with the healthy side,there was a reduced activation of the gluteus medius on the affected side(P=0.008).(3)The results indicate that patients with patellofemoral pain have abnormal lower limb biomechanical characteristics during step-down test,which are mainly manifested as changes in kinematic and indexes of the lower limb joints in the sagittal and frontal planes as well as changes in activation levels of the medial femoral and gluteus medius muscles.These changes reflect the fact that patients with patellofemoral pain adopt a stifflanding pattern during step-downs and show pronation of other joints of the lower extremity.In addition,abnormal lower extremity biomechanical characteristics are also present in the healthy limbs of patients with patellofemoral pain,and bilateral lower extremity asymmetry exists in such patients.

OBJECTIVE To investigate the impact of lysosomal associated membrane protein 2b(Lamp2b)modification on the mucosal immune efficacy of engineered exosome-based vaccines.METHODS In vitro experiments:The murine dendritic cell line DC2.4 was transfected with a plasmid encoding the Lamp2b-RBD fusion protein.Real-time quantitative PCR and Western blotting were employed to assess Lamp2b-RBD expressions,flow cytometry was used to evaluate the proportion of Lamp2b-RBD-positive cells,and immunofluorescence staining was performed to determine their membrane localization.Exosomes were isolated via ultracentrifugation,and their morphology and particle size distribution were examined using transmission electron microscopy and nanoparticle tracking analysis.Western blotting was applied to confirm exosomal marker proteins[cluster of differentiation 9(CD9),CD63,ALG-2-interacting protein X(Alix),and Golgi marker GM130]and Lamp2b-RBD expression.In vivo experiments:① Female BALB/c mice were divided into the Lamp2b-RBD-Exo group and the lipid nanoparticle(LNP)group,and administered intratracheally for mucosal immunization.Pulmonary reten-tion was assessed by immunofluorescence staining.② Female BALB/c mice were divided into three groups:placebo group(PBS group),Lamp2b-RBD-Exo intratracheal administration group,and Lamp2b-RBD-Exo intramuscular injection group(im).Immunizations were performed on days 0 and 14,and on days 7 and 21.The titers of RBD-specific immunoglobulin G(IgG)in serum and RBD-specific IgA and IgG antibodies in bronchoalveolar lavage fluid were determined by enzyme-linked immunosor-bent assay(ELISA).RESULTS In vitro experiments:Lamp2b-RBD-positive cells accounted for 71.16％.Lamp2b-RBD mRNA levels were upregulated 1 979-fold compared with controls,with Lamp2b-RBD proteins localized on the cell membrane.Purified engineered exosomes displayed regular morphology,expressed CD9,CD63,and Alix but not GM130,had an average diameter of approximately 124 nm,and carried 3 009 pg of RBD protein per 1×109 exosomes.In vivo experiments:At 4 h after administra-tion,fluorescence signals were observed in the lung tissues of both the Lamp2b-RBD-Exo and LNPs groups.At 24 h,the fluorescence signal in the LNPs group shifted to the liver,while in the Lamp2b-RBD-Exo group,the fluorescence expanded from the trachea to the bronchioles and lung tissue,showing significantly better distribution and retention capacity than the LNPs group.Seven days after immuniza-tion,both the Lamp2b-RBD-Exo and Lamp2b-RBD-Exo(im)groups induced RBD-specific IgG antibody titers.At 21 days after immunization,Lamp2b-RBD-Exo elicited a higher level of RBD-specific immune response,with serum IgG titers reaching 1∶8 100 and bronchoalveolar lavage fluid(BALF)IgA titers reaching 1∶300.No RBD-specific IgA antibody titers were detected in the BALF of the Lamp2b-RBD-Exo(im)group.CONCLUSION Lamp2b-RBD modification enables efficient RBD protein loading and enhances pulmonary retention of engineered exosomes,thereby inducing potent antigen-specific mucosal immune responses.

Objective: To investigate the effects and mechanisms of Astragalus Polysacharin(APS) on the proliferation and metastasis of breast cancer cells by regulating miR-107 and miR-346-mediated macrophage polarization in breast cancer-derived exosomes. Methods: Forty 8-week-old female BALB/c mice were selected and breast cancer xenograft models and 4T1 transplanted tumor models were established. The mice were divided into the control group and the APS group. The APS group mice received daily intragastric administration of APS for 25 days, while the control group mice were given the same amount of normal saline. After all treatments were completed, the mice were euthanized, and tumor tissues were isolated. Western blot and flow cytometry were used to detect the expressions of proliferating cell nuclear antigen(PCNA), Ki-67, CD206, CD163, inducible nitric-oxide synthase(iNOS), and CD86. The apoptosis of single-cell suspensions in tumor tissues was analyzed. Human breast cancer cell line MDA-MB-231 was cultured and stimulated with APS, and exosomes from the cell culture medium were collected. The proliferation, migration, and invasion of cells were detected by CCK-8 assay, scratch assay, permeability chamber cell invasion assay, and qRT-PCR. Differentially expressed genes were screened by bioinformatics. Results : By measuring the expressions of molecules related to breast cancer cell proliferation and metastasis, it was shown that APS treatment reduced the expressions of proliferation-related proteins(PCNA and Ki-67) and metastasis-related proteins(Vimentin) in MDA-MB-231 xenograft tumor tissues; and the polarization of tumor-associated macrophages was observed. APS treatment of 4T1 transplanted tumor tissues could reduce the number of M2 macrophages and increase the number of M1 macrophages, resulting in a decrease in the ratio of M2/M1 macrophages and an increase in cell apoptosis in 4T1 transplanted tumor tissues. The expressions of related proteins iNOS and CD86 increased, and CD206 and CD163 decreased. After APS treatment, the exosomes produced by MDA-MB-231 reduced the polarization of M2 macrophages and affected the expressions of miR-107 and miR-346. Conclusion APS inhibits the polarization of M2 macrophages by regulating the expression of miR-107 or miR-346 in breast cancer cell-derived exosomes, ultimately inhibiting the proliferation and metastasis of breast cancer cells.

OBJECTIVE To investigate the impact of lysosomal associated membrane protein 2b(Lamp2b)modification on the mucosal immune efficacy of engineered exosome-based vaccines.METHODS In vitro experiments:The murine dendritic cell line DC2.4 was transfected with a plasmid encoding the Lamp2b-RBD fusion protein.Real-time quantitative PCR and Western blotting were employed to assess Lamp2b-RBD expressions,flow cytometry was used to evaluate the proportion of Lamp2b-RBD-positive cells,and immunofluorescence staining was performed to determine their membrane localization.Exosomes were isolated via ultracentrifugation,and their morphology and particle size distribution were examined using transmission electron microscopy and nanoparticle tracking analysis.Western blotting was applied to confirm exosomal marker proteins[cluster of differentiation 9(CD9),CD63,ALG-2-interacting protein X(Alix),and Golgi marker GM130]and Lamp2b-RBD expression.In vivo experiments:① Female BALB/c mice were divided into the Lamp2b-RBD-Exo group and the lipid nanoparticle(LNP)group,and administered intratracheally for mucosal immunization.Pulmonary reten-tion was assessed by immunofluorescence staining.② Female BALB/c mice were divided into three groups:placebo group(PBS group),Lamp2b-RBD-Exo intratracheal administration group,and Lamp2b-RBD-Exo intramuscular injection group(im).Immunizations were performed on days 0 and 14,and on days 7 and 21.The titers of RBD-specific immunoglobulin G(IgG)in serum and RBD-specific IgA and IgG antibodies in bronchoalveolar lavage fluid were determined by enzyme-linked immunosor-bent assay(ELISA).RESULTS In vitro experiments:Lamp2b-RBD-positive cells accounted for 71.16％.Lamp2b-RBD mRNA levels were upregulated 1 979-fold compared with controls,with Lamp2b-RBD proteins localized on the cell membrane.Purified engineered exosomes displayed regular morphology,expressed CD9,CD63,and Alix but not GM130,had an average diameter of approximately 124 nm,and carried 3 009 pg of RBD protein per 1×109 exosomes.In vivo experiments:At 4 h after administra-tion,fluorescence signals were observed in the lung tissues of both the Lamp2b-RBD-Exo and LNPs groups.At 24 h,the fluorescence signal in the LNPs group shifted to the liver,while in the Lamp2b-RBD-Exo group,the fluorescence expanded from the trachea to the bronchioles and lung tissue,showing significantly better distribution and retention capacity than the LNPs group.Seven days after immuniza-tion,both the Lamp2b-RBD-Exo and Lamp2b-RBD-Exo(im)groups induced RBD-specific IgG antibody titers.At 21 days after immunization,Lamp2b-RBD-Exo elicited a higher level of RBD-specific immune response,with serum IgG titers reaching 1∶8 100 and bronchoalveolar lavage fluid(BALF)IgA titers reaching 1∶300.No RBD-specific IgA antibody titers were detected in the BALF of the Lamp2b-RBD-Exo(im)group.CONCLUSION Lamp2b-RBD modification enables efficient RBD protein loading and enhances pulmonary retention of engineered exosomes,thereby inducing potent antigen-specific mucosal immune responses.

OBJECTIVE To investigate the impact of vesicular stomatitis virus envelope glycopro-tein-G(VSV-G)modification on the mucosal immune efficacy of antigen-loaded engineered exosome vaccines.METHODS In vitro experiments:Dendritic cells(DCs)were divided into three groups:cell-control(treated with culture medium),receptor binding domain(RBD)(transfected with plasmid RBD),and RBD+VSV-G(co-transfected with plasmids RBD and VSV-G).Expression levels of RBD and VSV-G were assessed using Western blotting,flow cytometry,and immunofluorescence.Exosomes were extracted via ultracentrifugation,whose morphology,size distribution,and marker proteins were analyzed using transmission electron microscopy,nanoparticle tracking analysis,and Western blotting that confirmed the expressions of RBD and VSV-G in the exosomes.In vivo experiments:① Female BALB/c mice were divided into the control group Mock exosomes(Mock-Exo)(derived from the supernatant of cell-control),RBD decorated exosomes(RBD-Exo)(derived from the RBD cell supernatant),and RBD and VSV-G decorated exosomes(RBD+VSV-G-Exo)(derived from RBD+VSV-G cell supernatant).Follow-ing intranasal immunization with the respective vaccines,the nasal retention effects were evaluated using in vivo imaging.Flow cytometry was used to assess the ability to recruit immune cells to the nasal tissue.Serum RBD-specific immunoglobulin G(IgG)and mucosal immunoglobulin A(IgA)(bronchoal-veolar lavage fluid/nasal wash)were quantified at 7 and 21 d post-immunization by enzyme-linked immuno-sorbent assay.Body weight changes were monitored and key serum biochemical parameters along with histopathological damage to major organs were analyzed following immunization.② Female BALB/c mice were divided into the Mock-Exo group(intranasally inoculated with Mock-Exo),RBD+VSV-G-Exo group(intranasally inoculated with RBD+VSV-G-Exo),and RBD+VSV-G-Exo(im)group(intramus-cularly injected with RBD+VSV-G-Exo).RESULTS In vitro experiments:RBD and VSV-G were successfully expressed in cells,with positive rates of RBD+and VSV-G+cells at 64.4%and 31.2%,respectively.The extracted exosomes exhibited regular morphology and qualified purity,with a particle size of approximately 138 nm and successfully loaded RBD and VSV-G proteins.In vivo experiments:Compared to Mock-Exo and RBD-Exo,RBD+VSV-G-Exo prolonged nasal retention time to 96 h and markedly increased the numbers of CD49B+natural killer cells,CD11c+dendritic cells,and F4/80+macrophages in nasal tissues.RBD+VSV-G-Exo induced robust RBD-specific immune responses,with serum IgG titers,BALF IgA titers,and nasal wash IgA titers reaching 1∶5 215,1∶2 560,1∶1 114,respec-tively.In contrast,no RBD-specific IgA antibody titers were detected in the BALF and nasal wash of mice treated with RBD+VSV-G-Exo(im).Mice showed stable body weight gain during 30 d post-immu-nization.Major serum biochemical indices were within normal reference ranges,and no obvious patho-logical changes were observed in major organs or olfactory bulbs 7 d after immunization.CONCLU-SION VSV-G modification extends the retention time of engineered exosome vaccines in nasal tissues,enhance their ability to recruit immune cells,and induce a high-level antigen-specific respiratory mucosal immune response.

BACKGROUND:The pathogenesis of patellofemoral pain is complex,and poor movement patterns and incorrect muscle activation patterns have been suggested to increase patellofemoral joint stress and cause injury,but the results of current studies are not uniform.Current biomechanical studies of step-down test in patients with patellofemoral pain have focused on kinematic characteristics,and there is a lack of research on surface electromyographic characteristics.In addition,there are no studies that analyze the differences in biomechanical performance between the healthy and affected sides of patellofemoral pain patients compared with healthy subjects during the downward step test.OBJECTIVE:To investigate the kinematic and surface electromyographic characteristics of patients with patellofemoral pain during bilateral lower extremity step-downs.METHODS:Twenty-one men with patellofemoral pain and 21 healthy men were recruited,and both groups of subjects underwent a step-down test.Kinematic,kinetic and surface electromyographic data were synchronously collected using a three-dimensional dynamic capture system,a force platform and a surface electromyographic tester.RESULTS AND CONCLUSION:(1)Kinematics:Compared with the healthy control group,the affected and healthy sides of the patellofemoral pain group showed a smaller hip flexion angle(P=0.005,P=0.011),a larger hip internal rotation angle(P=0.033,P=0.039),and a larger knee valgus angle(P=0.001,P=0.001),and the affected side of the patellofemoral pain group exhibited a larger hip internal rotation angle(P=0.013),a smaller knee flexion angle(P=0.043),and a smaller ankle dorsiflexion angle(P=0.002);and compared with the healthy side,the affected side exhibited a smaller ankle dorsiflexion angle(P=0.002).(2)Surface electromyography:Compared with the healthy control group,the patellofemoral pain group showed reduced activation of the vastus medialis oblique(P=0.002),reduced activation of the gluteus medius(P=0.015),and a decreased vastus medialis oblique/vastus lateralis ratio(P=0.010)on the affected side;and compared with the healthy side,there was a reduced activation of the gluteus medius on the affected side(P=0.008).(3)The results indicate that patients with patellofemoral pain have abnormal lower limb biomechanical characteristics during step-down test,which are mainly manifested as changes in kinematic and indexes of the lower limb joints in the sagittal and frontal planes as well as changes in activation levels of the medial femoral and gluteus medius muscles.These changes reflect the fact that patients with patellofemoral pain adopt a stifflanding pattern during step-downs and show pronation of other joints of the lower extremity.In addition,abnormal lower extremity biomechanical characteristics are also present in the healthy limbs of patients with patellofemoral pain,and bilateral lower extremity asymmetry exists in such patients.

This ENETS guidance for well-differentiated nonfunctioning pancreatic neuroendocrine tumours(NF-Pan-NET),which published on Journal of Neuroendocrinology(2023),has been developed by a multidisciplinary working group,and provides up-to-date and practical advice on the management of these tumours.In this guideline,the authors discussed 10 troublesome questions about clinical practice,and summarized the extensive experience of their centers treating patients with NF-Pan-NET,and suggested that multidisciplinary participation is an essential part of NF-Pan-NET diagnosis and treatment.This paper aims to interpret the key contents of the guidelines in order to provide standardized clinical diagnosis and treatment procedures in NF-Pan-NET.

As a natural drug delivery carrier with rough and porous surface and hollow core， yeast microcapsules have good safety， high targeting and high stability， and have excellent application prospects in oral drug delivery systems. Yeast cells can be treated and washed with acid-base and organic solvents to obtain loose and porous yeast microcapsules. Yeast microcapsules can encapsulate drugs through electrostatic interactions， passive diffusion， hydrophobic interaction and other methods. The surface of yeast microcapsules is mainly composed of β-glucan， which can maintain stability in the gastrointestinal environment； it can be recognized by the surface-related receptors of immune cells， thus activating the immune response， and can be transported to the lesion site with the movement of lymphocytes after being ingested. Yeast microcapsules are safe and very suitable for delivering vaccines， anti-inflammatory drugs， and anti-tumor drugs. They can not only achieve oral delivery of the aforementioned drugs， but also enhance drug efficacy and improve drug targeting. In the future， more research on systemic transport mechanisms or the development of more efficient combination drug delivery systems can be carried out to fully exhibit the clinical value of yeast microcapsules.

Objective:To observe the path and anatomic distribution of cutaneous branch of second dorsal metacarpal artery(SDMA) from the back of hand to the web of the fingers, and to explore the feasibility and clinical effect on the transfer of free flap of SDMA.Methods:Between June 2018 and September 2018, with perfusion of red latex, 22 hand specimens were dissected to explore the course, vessel calibre and distribution of cutaneous branches of SDMA, and to discover the existence of an innervation of cutaneous nerve in Department of Hand Surgery of Tangshan Second Hospital. Later on, from February 2019 to July 2020, 2 thumb pulp defects of 2 patients were reconstructed with the free flaps of SDMA. One defect was in the left thumb and the other in the right, both were male and compression injuries. Size of thumb pulp and a skin defect was at 3.5 cm×2.0 cm in 1 patient, and 2.0 cm×2.5 cm in the other. There was no neurovascular injury, but 1 patient had a distal phalangeal fracture and a nail bed laceration. The sizes of the flaps were 3.8 cm×2.3 cm and 2.8 cm×2.5 cm. Functional exercises started from 3 weeks after surgery. Patients attended postoperation follow up regularly by outpatient visit, telephone or internet interviews. Follow-up observations included the appearance, texture, sensory recovery of the flaps and thumb functions.Results:Multiple perforating branches (4-9 branches) were found from SDMA, which distributed in the distal 1/3 of SDMA in the anatomic study. It was found that the outer diameter of SDMA was 0.76 mm±0.25 mm at the intersection of extensor tendon of index finger and that of the digital web artery was 0.71 mm±0.12 mm. The length of digital web artery was 11.00 mm±1.27 mm. The 2 surgically transferred flaps were all survived. One patient showed the function of thumb in excellent with two-point discrimination (TPD) at 7.0 mm, at 18 months of follow-up. The other patient showed good thumb movement, soft and elastic skin of the flap and with a 7.5 mm in TPD, at 15 months of follow-up. According to the Evaluation Standard of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, the results of the 2 flaps were all excellent.Conclusion:The flap of SDMA has a constant cutaneous nerve and a long vascular pedicle with an ideal vessel size. It is suitable for free transfer and can be used to reconstruct soft tissue defects of thumb.