AIM:To investigate the effect of intrinsic specific transforming growth factor-β(TGF-β)signaling on regeneration and repair of myofibers in acute skeletal myositismice model induced by cardiotoxin(CTX).METHODS:One hundred and eighty-six wild C57BL/6 mice and one hundred and thirty-eight mice with conditional knockout of TGF-β receptor 2(TGF-βr2)in myofibers(SM TGF-βr2-/-mice)were selected.CTX injection to anterior tibial muscle(TA)in-duced acute myoinjury in mice.Some SM TGF-βr2-/-mice were given Smad signaling agonist SRI-011381(SRI)intramus-cular injection.All mice were mainly divided into the following groups:control group,SM TGF-βr2-/-group and SM TGF-βr2-/-+SRI group.Twenty-four mice were selected in each group.RT-qPCR and immunofluorescence staining were used to detect the relative mRNA level,protein expression of inflammatory cytokines and low-density lipoprotein receptor-related protein 1(LRP1),respectively,while the relative protein expression of myosin heavy chain 3(MHY3)and embryonic myosine heavy chain(eMHC)in damaged muscle was detected by Western blot and immunofluorescence staining.In vi-tro,after being extracted from neonatal mice,myogenic precursor cells(MPCs)were cultured in an pro-inflammatory mi-lieu and treated with SRI,recombinant mouse extracellular matrix protein 1(rmECM1)alone or in combination.Hereby,they were divided into the following seven groups:control-MPCs group,control-MPCs+LPS group,TGF-βr2-/--MPCs group,TGF-βr2-/--MPCs+LPS group,TGF-βr2-/--MPCs+LPS+SRI group,TGF-βr2-/--MPCs+LPS+rmECM1 group,and TGF-βr2-/--MPCs+LPS+SRI+rmECM1 group.Six mice were selected in each group.RT-qPCR and Western blot were used to detect the relative mRNA level,protein expression of major histocompatibility complex class I molecules(MHC-I/H-2Kb),major histocompatibility complex class II molecules(MHC-II/H2-Eα),Toll-like receptor 3(TLR3),and LRP1.And the relative protein expression of MoyD and myogenin in myotubes was detected by immunofluorescence staining.RE-SULTS:In vivo,compared with control group,SM TGF-βr2-/-group showed the significant upregulation of pro-inflamma-tory cytokines(P<0.05),and the opposite trend of anti-inflammatory cytokines,LRP1,MHY3,eMHC in the injured muscle(P<0.05),with delayed regeneration and repair of myofibers.In vitro,compared with control-MPCs+LPS group,LRP1,MoyD and myogenin significantly downregulated in TGF-βr2-/--MPCs+LPS group,but the downregulation trend was corrected after giving SRI treatment(P<0.05).In addition,compared with the TGF-βr2-/--MPCs+LPS group,the combi-nation of rmECM1 and SRI significantly upregulated the protein expression of MyoD and myogenin(P<0.05).CONCLU-SION:In a mouse model of acute skeletal myositis,intrinsic TGF-β signaling specifically in myofibers regulates local im-mune behavior.It promotes the expression of LRP1 in damaged muscle via Smad2/3 signaling,and LRP1 can then fully bind to ECM1,thereby facilitating muscle regeneration and repair,and improving the prognosis of acute skeletal myositis.

AIM:To investigate the effect of intrinsic specific transforming growth factor-β(TGF-β)signaling on regeneration and repair of myofibers in acute skeletal myositismice model induced by cardiotoxin(CTX).METHODS:One hundred and eighty-six wild C57BL/6 mice and one hundred and thirty-eight mice with conditional knockout of TGF-β receptor 2(TGF-βr2)in myofibers(SM TGF-βr2-/-mice)were selected.CTX injection to anterior tibial muscle(TA)in-duced acute myoinjury in mice.Some SM TGF-βr2-/-mice were given Smad signaling agonist SRI-011381(SRI)intramus-cular injection.All mice were mainly divided into the following groups:control group,SM TGF-βr2-/-group and SM TGF-βr2-/-+SRI group.Twenty-four mice were selected in each group.RT-qPCR and immunofluorescence staining were used to detect the relative mRNA level,protein expression of inflammatory cytokines and low-density lipoprotein receptor-related protein 1(LRP1),respectively,while the relative protein expression of myosin heavy chain 3(MHY3)and embryonic myosine heavy chain(eMHC)in damaged muscle was detected by Western blot and immunofluorescence staining.In vi-tro,after being extracted from neonatal mice,myogenic precursor cells(MPCs)were cultured in an pro-inflammatory mi-lieu and treated with SRI,recombinant mouse extracellular matrix protein 1(rmECM1)alone or in combination.Hereby,they were divided into the following seven groups:control-MPCs group,control-MPCs+LPS group,TGF-βr2-/--MPCs group,TGF-βr2-/--MPCs+LPS group,TGF-βr2-/--MPCs+LPS+SRI group,TGF-βr2-/--MPCs+LPS+rmECM1 group,and TGF-βr2-/--MPCs+LPS+SRI+rmECM1 group.Six mice were selected in each group.RT-qPCR and Western blot were used to detect the relative mRNA level,protein expression of major histocompatibility complex class I molecules(MHC-I/H-2Kb),major histocompatibility complex class II molecules(MHC-II/H2-Eα),Toll-like receptor 3(TLR3),and LRP1.And the relative protein expression of MoyD and myogenin in myotubes was detected by immunofluorescence staining.RE-SULTS:In vivo,compared with control group,SM TGF-βr2-/-group showed the significant upregulation of pro-inflamma-tory cytokines(P<0.05),and the opposite trend of anti-inflammatory cytokines,LRP1,MHY3,eMHC in the injured muscle(P<0.05),with delayed regeneration and repair of myofibers.In vitro,compared with control-MPCs+LPS group,LRP1,MoyD and myogenin significantly downregulated in TGF-βr2-/--MPCs+LPS group,but the downregulation trend was corrected after giving SRI treatment(P<0.05).In addition,compared with the TGF-βr2-/--MPCs+LPS group,the combi-nation of rmECM1 and SRI significantly upregulated the protein expression of MyoD and myogenin(P<0.05).CONCLU-SION:In a mouse model of acute skeletal myositis,intrinsic TGF-β signaling specifically in myofibers regulates local im-mune behavior.It promotes the expression of LRP1 in damaged muscle via Smad2/3 signaling,and LRP1 can then fully bind to ECM1,thereby facilitating muscle regeneration and repair,and improving the prognosis of acute skeletal myositis.

Objective:To investigate and summarize the imaging and pathological features of non-acute occlusion following flow diverter (FD) implantation in animal models.Methods:Four experimental pigs (experimental group) that experienced non-acute occlusion (occlusion time exceeding 24 hours) within the FD stent implanted in the common carotid artery, and 19 pigs (control group) that did not experience stent occlusion during the same period were involved. Using an interventional approach under digital subtraction angiography (DSA), the 4 occluded FD lumens were mechanically opened. Optical coherence tomography (OCT), intravascular ultrasound (IVUS) and histopathological examinations were performed to evaluate the intraluminal composition and characteristics of the occlusive tissues. These findings were compared with non-occluded FD stents to summarize the imaging and pathological changes within the occluded FD lumen.Results:The occlusion times of the FD stents in the 4 experimental pigs were 16 weeks, 20 weeks, 20 weeks, and 24 weeks postoperatively. All occluded stents were successfully recanalized under DSA, with a technical success rate of 4/4. Among the 19 non-occluded FD stents, OCT and IVUS revealed uniform (16 stents) or non-uniform (3 stents) neointimal coverage of the stent struts, presenting as homogeneous high/slightly high signal intensity or medium echogenicity. Histopathological examination indicated that the neointima was primarily composed of smooth muscle cells and a small amount of fibrous connective tissues. In contrast, the 4 occluded FD stents demonstrated excessive neointimal proliferation and plaque formation, leading to luminal loss, as shown by OCT and IVUS. The occlusion tissues predominantly presented as homogeneous high signal intensity with weak attenuation (fibrous plaques) on OCT, with some regions showing blurred low signal intensity and strong attenuation (lipid plaques). IVUS presented homogeneous echogenicity (fibrous plaques) and hypoechogenic zones (lipid plaques). Histopathological examination showed that the occlusion tissues mainly consisted of smooth muscle cells, fibrous connective tissues, and lipids, accompanied by numerous foam cells and a minor presence of inflammatory cells.Conclusions:Histopathological examinations confirm that non-acute occlusion of FD is mainly caused by excessive hyperplasia of intima along with the formation of fibrous plaques and lipid plaques. OCT and IVUS have typical finding in imaging that can assist in determining the cause of stent occlusion as well as the lesion's nature, thereby providing crucial guidance for subsequent clinical treatment and drug selection.

Objective:To compare the therapeutic efficacy of the dual anteromedial and anterolateral approaches versus that of the anterior midline approach in the treatment of Wahlquist type C medial tibial plateau fractures accompanied by posterior column collapse.Methods:A retrospective study was conducted to analyze the 21 patients who had been treated for Wahlquist type C medial tibial plateau fractures plus posterior column collapse at The Fourth Orthopedic Ward, The 72nd Group Army Hospital of PLA between January 2019 and August 2023. The cohort included 13 males and 8 females, with an age of (43.3±6.7) years. The left side was involved in 14 fractures and the right side in 7 ones. The patients were divided into 2 groups based on their surgical approaches: a dual-approach group ( n=13) undergoing fixation via the dual anteromedial and anterolateral approaches, and a single-approach group ( n=8) undergoing fixation via the anterior midline approach. Comparative parameters included operative time, intraoperative blood loss, fracture healing time, quality of fracture reduction, medial proximal tibial angle (MPTA), incision complications, postoperative bone mass reduction quality (evaluated according to the Rasmussen anatomical criteria for tibial condyle fracture reduction), lateral tibial plateau instability, incidence of genu varum, and post-traumatic arthritis. Functional recovery of the lower limb joints was assessed at the final follow-up using the Merchant criteria. Results:No statistically significant differences were observed in the baseline characteristics between the 2 groups preoperatively, indicating comparability ( P>0.05). All patients were followed up for a mean duration of (38.1±11.3) months. The postoperative MPTA in the dual-approach group (86.8°±0.8°) was significantly larger than that in the single-approach group (85.5°±0.9°) ( P<0.05). Genu varum occurred in 1 patient in the dual-approach group and in 4 patients in the single-approach group, while lateral tibial plateau instability was observed in 1 patient in the dual-approach group and in 4 patients in the single-approach group, showing statistically significant differences between the 2 groups ( P<0.05). No statistically significant differences were found between the 2 groups regarding operative time, intraoperative blood loss, fracture healing time, quality of fracture reduction, incidence of incision complications, or incidence of post-traumatic arthritis ( P>0.05). At the final follow-up, no statistically significant difference was observed in the functional recovery of the lower limb joints assessed by the Merchant criteria between the 2 groups ( P>0.05). Conclusion:In the treatment of Wahlquist type C medial tibial plateau fractures accompanied by posterior column collapse, compared with the single anterior midline approach, the dual anteromedial and anterolateral approaches can restore more effectively the MPTA, and reduce the incidences of genu varum and lateral tibial plateau instability.

Objective:To investigate and summarize the imaging and pathological features of non-acute occlusion following flow diverter (FD) implantation in animal models.Methods:Four experimental pigs (experimental group) that experienced non-acute occlusion (occlusion time exceeding 24 hours) within the FD stent implanted in the common carotid artery, and 19 pigs (control group) that did not experience stent occlusion during the same period were involved. Using an interventional approach under digital subtraction angiography (DSA), the 4 occluded FD lumens were mechanically opened. Optical coherence tomography (OCT), intravascular ultrasound (IVUS) and histopathological examinations were performed to evaluate the intraluminal composition and characteristics of the occlusive tissues. These findings were compared with non-occluded FD stents to summarize the imaging and pathological changes within the occluded FD lumen.Results:The occlusion times of the FD stents in the 4 experimental pigs were 16 weeks, 20 weeks, 20 weeks, and 24 weeks postoperatively. All occluded stents were successfully recanalized under DSA, with a technical success rate of 4/4. Among the 19 non-occluded FD stents, OCT and IVUS revealed uniform (16 stents) or non-uniform (3 stents) neointimal coverage of the stent struts, presenting as homogeneous high/slightly high signal intensity or medium echogenicity. Histopathological examination indicated that the neointima was primarily composed of smooth muscle cells and a small amount of fibrous connective tissues. In contrast, the 4 occluded FD stents demonstrated excessive neointimal proliferation and plaque formation, leading to luminal loss, as shown by OCT and IVUS. The occlusion tissues predominantly presented as homogeneous high signal intensity with weak attenuation (fibrous plaques) on OCT, with some regions showing blurred low signal intensity and strong attenuation (lipid plaques). IVUS presented homogeneous echogenicity (fibrous plaques) and hypoechogenic zones (lipid plaques). Histopathological examination showed that the occlusion tissues mainly consisted of smooth muscle cells, fibrous connective tissues, and lipids, accompanied by numerous foam cells and a minor presence of inflammatory cells.Conclusions:Histopathological examinations confirm that non-acute occlusion of FD is mainly caused by excessive hyperplasia of intima along with the formation of fibrous plaques and lipid plaques. OCT and IVUS have typical finding in imaging that can assist in determining the cause of stent occlusion as well as the lesion's nature, thereby providing crucial guidance for subsequent clinical treatment and drug selection.

Objective:To compare the therapeutic efficacy of the dual anteromedial and anterolateral approaches versus that of the anterior midline approach in the treatment of Wahlquist type C medial tibial plateau fractures accompanied by posterior column collapse.Methods:A retrospective study was conducted to analyze the 21 patients who had been treated for Wahlquist type C medial tibial plateau fractures plus posterior column collapse at The Fourth Orthopedic Ward, The 72nd Group Army Hospital of PLA between January 2019 and August 2023. The cohort included 13 males and 8 females, with an age of (43.3±6.7) years. The left side was involved in 14 fractures and the right side in 7 ones. The patients were divided into 2 groups based on their surgical approaches: a dual-approach group ( n=13) undergoing fixation via the dual anteromedial and anterolateral approaches, and a single-approach group ( n=8) undergoing fixation via the anterior midline approach. Comparative parameters included operative time, intraoperative blood loss, fracture healing time, quality of fracture reduction, medial proximal tibial angle (MPTA), incision complications, postoperative bone mass reduction quality (evaluated according to the Rasmussen anatomical criteria for tibial condyle fracture reduction), lateral tibial plateau instability, incidence of genu varum, and post-traumatic arthritis. Functional recovery of the lower limb joints was assessed at the final follow-up using the Merchant criteria. Results:No statistically significant differences were observed in the baseline characteristics between the 2 groups preoperatively, indicating comparability ( P>0.05). All patients were followed up for a mean duration of (38.1±11.3) months. The postoperative MPTA in the dual-approach group (86.8°±0.8°) was significantly larger than that in the single-approach group (85.5°±0.9°) ( P<0.05). Genu varum occurred in 1 patient in the dual-approach group and in 4 patients in the single-approach group, while lateral tibial plateau instability was observed in 1 patient in the dual-approach group and in 4 patients in the single-approach group, showing statistically significant differences between the 2 groups ( P<0.05). No statistically significant differences were found between the 2 groups regarding operative time, intraoperative blood loss, fracture healing time, quality of fracture reduction, incidence of incision complications, or incidence of post-traumatic arthritis ( P>0.05). At the final follow-up, no statistically significant difference was observed in the functional recovery of the lower limb joints assessed by the Merchant criteria between the 2 groups ( P>0.05). Conclusion:In the treatment of Wahlquist type C medial tibial plateau fractures accompanied by posterior column collapse, compared with the single anterior midline approach, the dual anteromedial and anterolateral approaches can restore more effectively the MPTA, and reduce the incidences of genu varum and lateral tibial plateau instability.

Objective To investigate the effect of E2 signaling in myofibers on muscular macrophage efferocytosis in mice with cardiotoxin-induced acute skeletal muscle injury.Methods Female wild-type C57BL/6 mice with and without ovariectomy and male C57BL/6 mice were given a CTX injection into the anterior tibial muscle to induce acute muscle injury,followed by intramuscular injection of β-estradiol(E2)or 4-hydroxytamoxifen(4-OHT).The changes in serum E2 of the mice were detected using ELISA,and the number,phenotypes,and efferocytosis of the macrophages in the inflammatory exudates and myofiber regeneration and repair were evaluated using immunofluorescence staining and flow cytometry.C2C12 cells were induced to differentiate into mature myotubes,which were treated with IFN-γ for 24 before treatment with β-Estradiol or 4-OHT.The treated myotubes were co-cultured with mouse peritoneal macrophages in a 1:2 ratio,followed by addition of PKH67-labeled apoptotic mouse mononuclear spleen cells induced by UV irradiation,and macrophage efferocytosis was observed using immunofluorescence staining and flow cytometry.Results Compared with the control mice,the female mice with ovariectomy showed significantly increased mononuclear macrophages in the inflammatory exudates,with increased M1 cell percentage,reduced M2 cell percentage and macrophage efferocytosis in the injured muscle,and obviously delayed myofiber regeneration and repair.In the cell co-culture systems,treatment of the myotubes with β-estradiol significantly increased the number and proportion of M2 macrophages and macrophage efferocytosis,while 4-OHT treatment resulted in the opposite changes.Conclusion In injured mouse skeletal muscles,myofiber E2 signaling promotes M1 to M2 transition to increase macrophage efferocytosis,thereby relieving inflammation and promoting muscle regeneration and repair.

Objective:To investigate the application value of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in evaluating flow diverter (FD) apposition and endothelialization in aneurysm animal models, and analyze the effect of incomplete stent apposition (ISA) on aneurysm lumen healing and stent endothelialization.Methods:Lateral common carotid artery aneurysm models in swines were established by surgical method and then FD was implanted. Immediately after surgery, OCT and IVUS were used to evaluate the locations and degrees of ISA, and difference between these 2 methods in evaluating FD apposition was compared. DSA was performed at 12 weeks after surgery to evaluate the aneurysm occlusion (Kamran grading) and stent patency. OCT and IVUS were used again to observe the stent endothelial situation; by comparing with histopathologic results, effect of ISA on aneurysm healing and stent endothelialization was analyzed.Results:Lateral common carotid artery aneurysm models in 6 swines were established, and 6 Tubridge FDs were successfully implanted. Compared with IVUS (3 stents, 4 locus), OCT could detect more ISA (6 stents, 14 locus); and the vascular diameter change area (7 locus), aneurysm neck area (4 locus) and the head and tail of FD (3 locus) were the main sites of FD malapposition; average distance between stent wire and vessel wall was (560.14±101.48) μm. At 12 weeks after surgery, DSA showed that 1 patient had a little residual contrast agent at the aneurysm neck (Kamran grading 3), and the remaining 5 had complete aneurysm occlusion (Kamran grading 4). One FD had moderate lumen stenosis, and the other 5 FDs had lumen patency. OCT indicated mostly disappeared acute ISA; ISA proportion decreased to 21.4 % (3/14), including 2 in the aneurysm neck and 1 in the partial stent. Histopathological results showed bare stent woven silk, without obvious endothelial coverage; in one FD with luminal stenosis, intimal hyperplasia was mainly composed of vascular smooth muscle cells.Conclusion:In carotid artery aneurysm model with FD implantation, OCT can detect more ISA than IVUS; most acute ISA have good outcome at 12 th week of follow-up, while severe ISA can cause delayed FD endothelialization and delayed aneurysm occlusion.

Objective To investigate the effect of E2 signaling in myofibers on muscular macrophage efferocytosis in mice with cardiotoxin-induced acute skeletal muscle injury.Methods Female wild-type C57BL/6 mice with and without ovariectomy and male C57BL/6 mice were given a CTX injection into the anterior tibial muscle to induce acute muscle injury,followed by intramuscular injection of β-estradiol(E2)or 4-hydroxytamoxifen(4-OHT).The changes in serum E2 of the mice were detected using ELISA,and the number,phenotypes,and efferocytosis of the macrophages in the inflammatory exudates and myofiber regeneration and repair were evaluated using immunofluorescence staining and flow cytometry.C2C12 cells were induced to differentiate into mature myotubes,which were treated with IFN-γ for 24 before treatment with β-Estradiol or 4-OHT.The treated myotubes were co-cultured with mouse peritoneal macrophages in a 1:2 ratio,followed by addition of PKH67-labeled apoptotic mouse mononuclear spleen cells induced by UV irradiation,and macrophage efferocytosis was observed using immunofluorescence staining and flow cytometry.Results Compared with the control mice,the female mice with ovariectomy showed significantly increased mononuclear macrophages in the inflammatory exudates,with increased M1 cell percentage,reduced M2 cell percentage and macrophage efferocytosis in the injured muscle,and obviously delayed myofiber regeneration and repair.In the cell co-culture systems,treatment of the myotubes with β-estradiol significantly increased the number and proportion of M2 macrophages and macrophage efferocytosis,while 4-OHT treatment resulted in the opposite changes.Conclusion In injured mouse skeletal muscles,myofiber E2 signaling promotes M1 to M2 transition to increase macrophage efferocytosis,thereby relieving inflammation and promoting muscle regeneration and repair.

Objective:To explore the safety and feasibility of optimized pathological evaluation system of donor's kidney and modified surgery during adult dual kidney transplantation(DKT)and evaluate its effectiveness to provide more alternative protocols for kidney transplantation from extended criteria donors.Methods:DKT was performed in 10 recipients using the same protocol from June 2019 to May 2021.And retrospective reviewing was performed for clinical data, including characteristics of donors and recipients, optimized pathological evaluation system, modified surgery, treatment regimens, complications and follow-ups.Results:There were 8 male and 2 female donors with an age of(57.9±12.8)years and BMI(24.1±4.1)kg/m 2.The percentage of DCD was 70% and DBD 30%.The serum creatinine before procurement was 107.6(93.3-163.5)μmol/l.Zero-point puncture biopsy was performed for both kidneys and optimized pathological evaluation system was implemented(Banff criteria & Remuzzi score). The pathological results indicated that glomerular sclerosis for left and right kidneys were 2.0(1.5-2.0)and 1.5(1.0-2.0). And Remuzzi score for left and right kidneys were(4.4±1.2)and(3.6±1.5)points respectively.All recipients were male with an age of(43.1±9.0)years and BMI(22.2±1.9)kg/m 2.All PRAs were negative pre-operation.Modified surgery was performed in all recipients(two kidneys were implanted outside iliac vessels without patch and artery of superior kidney was anastomosed to internal iliac artery). Operative duration was(195±54.3)min and serum creatinine before discharge 125.0(102.0-199.0)μmol/L.Renal dynamic scintigraphy indicated that glomerular filtration rate was(30.0±8.2)ml/min for left kidney and(29.2±13.9)ml/min for right kidney.MRA results indicated that morphologies of renal arteries and veins were regular.The time between operation and discharge was(22.4±4.7)days.Compared with SKT, serum creatinine before discharge of DKT was lower and DGF incidence of DKT was higher without statistical significance.The time between operation and discharge was longer for DKT than that for SKT( P<0.05). The complications consisted of 20% donor derived infection(DDI)and 50% DGF.And there was no surgical complication associated with vessels and ureter.Renal function remained stable during 6-month follow-ups. Conclusions:Optimized pathological evaluation system of donor's kidney and modified surgery during adult dual kidney transplantation are both safe and feasible.The postoperative function of transplanted dual kidney is successfully restored.However, long-term follow-ups are required for evaluating its effectiveness.