Sustainable Vat Photopolymerization-Based 3D-Printing through Dynamic Covalent Network Photopolymers.

Vat photopolymerization (VPP) based three-dimensional (3D) printing, including stereolithography (SLA) and digital light projection (DLP), is known for producing intricate, high-precision prototypes with superior mechanical properties. However, the challenge lies in the non-recyclability of covalently crosslinked thermosets used in these printing processes, limiting the sustainable utilization of printed prototypes. This review paper examines the recently explored avenue of VPP 3D-printed dynamic covalent network (DCN) polymers, which enable reversible crosslinks and allow for the reprocessing of printed prototypes, promoting sustainability. These reversible crosslinks facilitate the rearrangement of crosslinked polymers, providing printed polymers with chemical/physical recyclability, self-healing capabilities, and degradability. While various mechanisms for DCN polymer systems are explored, this paper focuses solely on photocurable polymers to highlight their potential to revolutionize the sustainability of VPP 3D printing.

[Research progress of tibial-graft fixation methods on anterior cruciate ligament reconstruction].

Objective: To review the studies about the tibial-graft fixation methods on anterior cruciate ligament (ACL) reconstruction, in order to provide clinical reference. Methods: The literature about the tibial-graft fixation methods on ACL reconstruction at home and abroad was extensively reviewed, and the factors that affect the selection of fixation methods were summarized. Results: The knee flexion angle, graft tension, and graft fixation device are mainly considered when the tibial-graft was fixed on ACL reconstruction. At present, the graft is mainly fixed at 0°/30° of knee flexion. The study shows that the knee joint is more stable after fixed at 30°, while the incidence of knee extension limitation decrease after fixed at 0°. In terms of graft tension, a good effectiveness can be obtained when the tension level is close to 90 N or the knee flexion is 30° to recover the affected knee over-restrained 2 mm relative to the healthy knee. In terms of the graft device, the interference screw is still the most commonly used method of tibial-graft fixation, with the development of all-inside ACL reconstruction in recent years, the cortical button fixation may become the mainstream. Conclusion: Arthroscopic reconstruction is the main treatment of ACL rupture at present. However, there is no optimal fixation method for the tibial-graft, the advantages and disadvantages of each fixation methods need to be further studied.

4D-Printed Hydrogel Actuators through Diffusion-Path Architecture Design.

Recently, smart hydrogels have garnered considerable attention as biomedical devices, and several approaches have been introduced for their fabrication, including the incorporation of stimulus-responsive additives, utilization of molecular imprinting techniques, and application of multilayered hydrogels. However, the nonuniform properties resulting from these approaches limit the practical applications of hydrogels by causing inconsistent performance and behavior. In this study, we propose a novel approach to manipulating the swelling kinetics of hydrogels by engineering their diffusion-path architecture. By simply adjusting the diffusion path length within the hydrogel, we achieved a significant change in swelling kinetics. This approach enables precise control over the diffusion and transport processes within the hydrogel, resulting in enhanced swelling kinetics when reducing the diffusion path length. Furthermore, by strategically designing the diffusion-path architecture of a 3D-printed hydrogel specimen, we can fabricate smart hydrogel actuators that exhibit reversible shape transformations during swelling and deswelling through a nonequilibrium differential swelling. The proposed approach eliminates the need to modify the spatial properties of hydrogel structures such as cross-linking density, polymer, or additive compositions, thereby achieving uniform properties throughout the hydrogel and creating new possibilities for the development of advanced 4D-printed biomedical devices.

Study on the Reactivity Activation of Coal Gangue for Efficient Utilization.

In this study, the research aim is to enhance the activity index of activated coal gangue and study its activation mechanism. The activation process of coal gangue was optimized through orthogonal tests, and the Back-Propagation (BP) neural network model was improved using a genetic algorithm. With the effects of grinding duration, calcination temperature, and calcination duration, the morphological changes and phase transformation processes of coal gangue were studied at the micro and meso levels to clarify the activation mechanism. The results indicated that the effect of calcination temperature on the strength activity index of coal gangue was most significant, followed by grinding duration and calcination duration. The potential activity of coal gangue can be effectively stimulated through mechanical and thermal activation, and the content of potential active minerals in coal gangue powders was also increased. The activation process of coal gangue for the optimal scheme was obtained as grinding at 76 min first and thermal treatment at 54 min at 749 °C. As the thermal activation under 950 °C, some unstable external hydroxyls, and internal hydroxyls in kaolinite from coal gangue were removed, the AlⅥ-O octahedron was destroyed, and kaolinite was transformed into spatially disordered metakaolinite with very high activity.

Effects of phosphine ligands in nickel-catalyzed decarbonylation reactions of lactone.

Due to the ubiquity of carbonyl compounds and the abundance of nickel on the earth, nickel-catalyzed decarbonylation has garnered increasing attention in recent years. This type of reaction has seen significant developments in various aspects; however, certain challenges concerning reactivity, selectivity, and transformation efficiency remain pressing and demand urgent resolution. In this study, we employed DFT calculations to investigate the mechanism of nickel-catalyzed decarbonylation reactions involving lactones, as well as the effects of phosphine ligands. Mechanically, Ni(0) first activates the C(acyl)-O bond of the lactone, followed by a decarbonylation step, and ultimately results in reductive elimination under carbonyl coordination to yield the product. Through a comprehensive examination of the electronic and steric effects of the phosphine ligands, we deduced that the electronic effect of the ligand plays a dominant role in the decarbonylation reaction. By enhancing the electron-withdrawing ability of the ligand, the energy barrier of the entire reaction can be significantly reduced. The obtained insights should be valuable for understanding the detailed mechanism and the role of phosphine ligands in nickel catalysis. Moreover, they offer crucial clues for the rational design of more efficient catalytic reactions.

Enhancing the mechanical strength and toughness of epoxy resins with linear POSS nano-modifiers.

Glass transition temperature (T g) always deteriorates while improving the strength of epoxy resins which inherently suffer from brittleness. Herein, novel linear polyhedral oligomeric silsesquioxane (POSS)-epoxy nano-modifiers are synthesized with variable contents of POSS. The thermomechanical properties and chemical structure study of the POSS-epoxy indicates significant differences of the rigid POSS content in the linear nano-modifiers. By taking advantage of the synergistic effect of nanofillers and linear polymers, the modifiers disperse at the molecular level when POSS-epoxy is utilized as a co-curing agent for epoxy resins, allowing the applied force to be transferred into the polymer matrix. A good balance of T g, stiffness, and fracture toughness can be obtained. At 5 wt% of the nano-modifier, the resultant epoxy resins showed 27% enhancement in the Young's modulus relative to the neat epoxy. In addition, the T g and strength of epoxy thermosets are improved due to the increased cross-linking density, rough surface and tortuous path that resulted in good dispersion of energy during crack propagation.

Toughened Hydrogels for 3D Printing of Soft Auxetic Structures.

Materials with negative Poisson's ratio have attracted considerable attention and offered high potential applications as biomedical devices due to their ability to expand in every direction when stretched. Although negative Poisson's ratio has been obtained in various base materials such as metals and polymers, there are very limited works on hydrogels due to their intrinsic brittleness. Herein, we report the use of methacrylated cellulose nanocrystals (CNCMAs) as a macro-cross-linking agent in poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels for 3D printing of auxetic structures. Our developed CNCMA-pHEMA hydrogels exhibit significant improvements in mechanical properties, which is attributed to the coexistence of multiple chemical and physical interactions between the pHEMA and CNCMAs. Structures printed by using CNCMA-pHEMA hydrogels show auxetic behavior with greatly enhanced toughness and stretchability compared to the hydrogel with a traditional cross-linking agent. Such strong and tough auxetic hydrogels would contribute toward establishing advanced flexible implantable devices such as biodegradable oesophageal self-expandable stents.

Comparison of Rapid Rehabilitation after Anterior Cruciate Ligament Reconstruction with Tensioning Technique and Traditional Rehabilitation.

To investigate the efficacy of a fast rehabilitation program for the recovery of knee joint function after arthroscopic autologous hamstring tendon transplantation for reconstruction of the anterior cruciate ligament (ACL), from January 1, 2017, to March 31, 2019, a total of 65 patients with ACL injury were randomly divided into a study group and a control group. Both groups were treated with autologous hamstring tendon to reconstruct the anterior cruciate ligament, arthroscopic transplantation, and decompression techniques. The research group was treated with a fast rehabilitation program. The control group was treated with traditional rehabilitation program. Knee flexion angles were measured at 2, 4, and 8 weeks postoperatively. KT-1000 knee anterior stability was measured at 3, 6, and 12 months after operation. Knee function was assessed by subjective knee function assessment scale (IKDC) and Lysholm knee score. The knee curvature, KT-1000 measurement, IKDC score, and Lysholm score were compared between the two groups before and after treatment. KT-1000 measured value, IKDC score, and Lysholm score in 2 groups were significantly improved 3, 6, and 12 months compared with those before treatment, and the difference was statistically significant (P < 0.001). Comparison between the two groups: 2 weeks, 4 weeks, and 8 weeks after treatment, the knee curvature in the study group was better than that in the control group, and the difference was statistically significant (P < 0.001); there was no significant difference in the measured values of KT-1000 between the two groups 3, 6, and 12 months after treatment (P > 0.05); IKDC score and Lysholm score in the study group 3 and 6 months after treatment were significantly better than those in the control group, with statistical significance (P < 0.001); there was no significant difference in IKDC score and Lysholm score between the two groups 12 months after treatment (P >0.05). Autograft hamstring tendon transplantation and tense-reducing technique for anatomical reconstruction of anterior cruciate ligament under arthroscopy combined with rapid rehabilitation program can quickly, safely, and effectively restore the knee function of patients, greatly shortening the rehabilitation period of patients.

Hofmeister Effect Mediated Strong PHEMA-Gelatin Hydrogel Actuator.

Hydrogels have become popular in biomedical applications, but their applications in muscle and tendon-like bioactuators have been hindered by low toughness and elastic modulus. Recently, a significant toughness enhancement of a single hydrogel network has been successfully achieved by the Hofmeister effect. However, little has been conducted for the Hofmeister effect on the hybrid hydrogels, although they have a special network structure consisting of two types of polymer components. Herein we fabricated hybrid poly(2-hydroxyethyl methacrylate) (PHEMA)-gelatin hydrogels with high mechanical performance and stimuli response. An ideal bicontinuous phase separation structure of the PHEMA (rigid) and gelatin (ductile) was observed with embedded microdisc-like gelatin in the three-dimensional polymeric network of PHEMA. A significant enhancement of mechanical performance by the Hofmeister effect was attributed to the salting-out-induced stronger and closer interphase interaction between PHEMA and gelatin. A superior comprehensive mechanical performance with fracture elongation over 650%, tensile strength of 5.2 MPa, toughness of 13.5 MJ/m3, and modulus of 45.6 MPa was achieved with the salting-out effect. More specifically, the synergy of phase separation and Hofmeister effect enable the hydrogel to contract with an enhanced modulus in high-concentration salt solutions, while the same hydrogel swells and relaxes in dilute solutions, exhibiting an ionic stimulus response and excellent shape-memory properties like those of most artificial muscle. This is manifested in highly stretched, twisted, and knotted hydrogel strips that can rapidly recover their original shape in a dilute salt solution. The high strength and modulus, ionic stimuli response, and shape memory property make the hybrid hydrogel a promising material for bioactuators in various biomedical applications.

Correlations between forkhead box D1 expression and clinicopathological characteristics of patients with bladder cancer and influence on biological behaviors of bladder cancer cells. / Correlación entre la expresión de Forkhead Box D1 y características clínico-patológicas de pacientes con cáncer de vejiga y su influencia en el comportamiento biológico de las células tumorales.

OBJECTIVES: To investigate the correlationsbetween forkhead box D1 (FOXD1) expressionand clinicopathological characteristics of bladdercancer and influence on the biological behaviors ofbladder cancer cells. METHODS: The overall survival rate of 87 bladdercancer patients was evaluated to explore the predictivevalue of FOXD1. The expressions of FOXD1 in 87 bladdercancer tissues and 26 adjacent tissues were measuredthrough immunohistochemistry, and the correlationsbetween FOXD1 expression and clinicopathologicalcharacteristics of patients were analyzed. FOXD1 mimicand FOXD1 siRNA were mixed and transferred intoT24 cells to construct FOXD overexpression and knockdowncell lines. Cell counting kit-8, wound-healing andTranswell migration assays were performed to detectcell proliferation, migration and invasion. RESULTS: Prediction using bioinformatics websiteshowed that FOXD1 was highly expressed inbladder cancer tissues. The overall survival rate wassignificantly lower in bladder cancer patients withhigh FOXD1 expression than that in those with lowexpression (Psignificantly higher in bladder cancer tissues thanthat in adjacent tissues. The expression of FOXD1in bladder cancer tissues had no significant differencesamong patients with different gender, agesand tumor sizes, but significant differences amongthose with different tumor numbers, clinical stagesand histological grades (PNC group, the proliferation, migration and invasionof bladder cancer cells were significantly promotedin FOXD1 group and suppressed in si-FOXD1group (PCONCLUSIONS: FOXD1 is highly expressed in bladdercancer tissues and cells, being closely associatedwith the development and progression of bladder cancer.It facilitates the proliferation, migration and invasionof cells and carcinogenesis. FOXD1 may be a newtarget for bladder cancer therapy.

OBJETIVOS: Investigar la correlaciónentre la expresión de Forkhead Box D1 (FOXD1) y lascaracterísticas clínico patológicas del cáncer de vejigay su influencia en el comportamiento biológico de lascélulas tumorales.MÉTODOS: Se evaluó la supervivencia global de 87pacientes con cáncer de vejiga para explorar el valorpredictivo de FOXD1. La expresión de FOXD1 en 87 tejidostumorales y 26 tejidos adyacentes fueron evaluadoscon inmunohistoquímica y se analizaron las correlacionesentre FOXD1 y las características clínico-patológicas.FOXD1 mimic y FOXD1 siARN fueron mezclados ytransferidos a células T24 para crear la sobreexpresiónFOXD y causar un knockdown en las líneas celulares. Seutilizaron los ensayos Cell counting kit-8, wound-healingand Transwell migration para detectar la proliferacion,migración e invasion celular. RESULTS: La predicción obtenida con el uso de lapágina web bioinformatics mostró que FOXD1 estabaaltamente expresado en tejidos tumorales vesicales.La supervivencia global fue significativamente másbaja en pacientes con cáncer de vejiga con alta expresiónde FOXD1 que aquellos con baja expresión(Pmás alta en tejidos con cáncer de vejiga queen los tejidos adyacentes. La expresión de FOXD1 entejidos con cáncer de vejiga no presentó diferenciassignificativas en relacion al género, edad y tamañotumoral de los pacientes, pero sí presentó diferenciassignificativas entre el número de tumores, el estadioclínico y el grado histológico (Pcon el grupo NC, la proliferación, migración e invasionde las células tumorales fueron significativamentepromovidas en el grupo FOXD1 y suprimidasen el grupo si-FOXD1 (PCONCLUSIONS: FOXD1 está íntimamente asociadoal desarrollo y progresión del cáncer de vejiga al encontrarsealtamente expresado en las células del tejidotumoral. Facilita la proliferación, migración e invasióncelular en la carcinogénesis. FOXD1 podría ser unanueva diana para el tratamiento del cáncer de vejiga.

LINC00665 regulates hepatocellular carcinoma by modulating mRNA via the m6A enzyme.

This study aimed to reveal the mechanism by which long noncoding RNAs (lncRNAs) modulate hepatocellular carcinoma (HCC) by regulating mRNA via the N6-methyladenosine (m6A) enzyme. The expression and clinical data of 365 HCC patients and 50 healthy control samples were downloaded from the the Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DElncRNAs) and differentially expressed mRNAs (DEmRNAs) screened using limma packages from the R. m6A2Target database were used to predict the relationship between m6A enzyme-lncRNA and m6A enzyme-mRNA. The mRNAs in the lncRNA-m6A enzyme-mRNA network were subjected to enrichment analysis. Cox regression analysis was used to screen for RNAs significantly related to HCC prognosis. The expression of differentially expressed RNAs (DERs) was verified using the TCGA dataset and GSE55092. Eighty-five DElncRNAs and 747 DEmRNAs were identified. The mRNAs in the lncRNA-m6A enzyme-mRNA network were primarily involved in mitotic cell division, the p53 signaling pathway, and the cell cycle. Three lncRNAs and 14 mRNAs were significantly associated with HCC prognosis. Furthermore, the expression of 12 DERs differed significantly between patients in the early and advanced stages. LINC00665 was predicted to regulate 11 mRNAs by modulating IGF2BP1, IGF2BP2, and YTHDF1. Thus, this study provides new insights into the roles of lncRNA and m6A enzymes in HCC.

Effects of Coculture Fibroblasts and Vascular Endothelial Cells on Proliferation and Osteogenesis of Adipose Stem Cells.

BACKGROUND: The development of tissue engineering provides a new method for the clinical treatment of bone defects, but the problems of slow formation and slow vascularization of tissue engineered bone have always existed. Studies have shown that the combined culture system of vascular endothelial cells and adipose stem cells is superior to single cell in repairing bone defects. With the excellent proliferation ability, secretion of synthetic collagen and a variety of regulatory factors and fibroblasts can differentiate into osteoblasts and have the potential to be excellent seed cells involved in tissue engineering bone construction. OBJECTIVE: To investigate the effects of combined culture of fibroblasts, vascular endothelial cells, and adipose stem cells on proliferation and osteogenic differentiation of adipose stem cells. METHODS: The cells were divided into 4 groups: adipose stem cell group, adipose stem cell+vascular endothelial cell coculture group, adipose stem cell+fibroblast coculture group, and adipose stem cell+vascular endothelial cell+fibroblast coculture group. The morphological changes of the cells were observed under an inverted microscope. After 1, 3, 5, 7, and 9 days of coculture, the proliferation of adipose stem cells in each group was detected by a CCK-8 method and the growth curve was plotted. Adipose stem cells in each group were stained with alizarin red and alkaline phosphatase at days 7, 14, 21, and 28. At the third week of coculture, Western blot was used to detect the expression level of bone morphogenetic protein 2 of adipose stem cells in each group. Results and Conclusions. (1) After 14 days of culture, some cells in the adipose stem cell+vascular endothelial cell+fibroblast coculture group fused into clumps and distributed in nests, while the adipose stem cells in the adipose stem cell group had a single cell morphology and no cell clusters were observed. (2) The cell growth curves were basically the same in each group, and the absorbance value increased gradually. The absorbance value of the adipocyte+vascular endothelial cell+fibroblast coculture group was the highest, followed by the adipocyte+fibroblast coculture group and then the adipocyte+fibroblast coculture group. (3) Alizarin red staining showed negative reaction in each group on the 7th day, and a small number of red positive cells gradually appeared in each group as time went on. On the 28th day, red positive cells were found in all groups, and most of them were in the coculture group of adipose stem cells+vascular endothelial cells+fibroblasts, showing red focal. The coculture group of adipose stem cells+vascular endothelial cells and adipose stem cells+fibroblasts was less, and the adipose stem cell group was the least. On day 28 of alkaline phosphatase staining, cells in each group had red positive particles, and the adipose stem cell+vascular endothelial cell+fibroblast coculture group and adipose stem cell+fibroblast coculture group had the most, followed by the adipose stem cell+vascular endothelial cell coculture group and then the adipose stem cell group. (4) Bone morphogenetic protein 2 was expressed in all groups, especially in adipose stem cell+fibroblast coculture group and adipose stem cell+vascular endothelial cell+ fibroblast coculture group. (5) Fibroblast could promote adipose stem cell osteogenic differentiation better than vascular endothelial cells, but the proliferation effect was not as good as vascular endothelial cells. The coculture system of fibroblast combined with vascular endothelial cells and adipose stem cells promoted the proliferation of adipose stem cells and the rapid and efficient differentiation of adipose stem cells into osteoblasts.

Machine Learning-Driven Biomaterials Evolution.

Biomaterials is an exciting and dynamic field, which uses a collection of diverse materials to achieve desired biological responses. While there is constant evolution and innovation in materials with time, biomaterials research has been hampered by the relatively long development period required. In recent years, driven by the need to accelerate materials development, the applications of machine learning in materials science has progressed in leaps and bounds. The combination of machine learning with high-throughput theoretical predictions and high-throughput experiments (HTE) has shifted the traditional Edisonian (trial and error) paradigm to a data-driven paradigm. In this review, each type of biomaterial and their key properties and use cases are systematically discussed, followed by how machine learning can be applied in the development and design process. The discussions are classified according to various types of materials used including polymers, metals, ceramics, and nanomaterials, and implants using additive manufacturing. Last, the current gaps and potential of machine learning to further aid biomaterials discovery and application are also discussed.

Biomaterials by design: Harnessing data for future development.

Biomaterials is an interdisciplinary field of research to achieve desired biological responses from new materials, regardless of material type. There have been many exciting innovations in this discipline, but commercialization suffers from a lengthy discovery to product pipeline, with many failures along the way. Success can be greatly accelerated by harnessing machine learning techniques to comb through large amounts of data. There are many potential benefits of moving from an unstructured empirical approach to a development strategy that is entrenched in data. Here, we discuss the recent work on the use of machine learning in the discovery and design of biomaterials, including new polymeric, metallic, ceramics, and nanomaterials, and how machine learning can interface with emerging use cases of 3D printing. We discuss the steps for closer integration of machine learning to make this exciting possibility a reality.

Effects of Tissue-engineered Bone by Coculture of Adipose-derived Stem Cells and Vascular Endothelial Cells on Host Immune Status.

AIM: The study aimed to explore the effects of tissue-engineered bone constructed with partially deproteinized biologic bone (PDPBB) and coculture of adipose-derived stem cells (ADSCs) and vascular endothelial cells (VECs) on host immune status, providing a very useful clue for the future development of bone engineering. METHODS: Tissue-engineered bones constructed by PDPBB and ADSCs, VECs or coculture of them were implanted into the muscle bag of bilateral femurs of Sprague-Dawley rats. Partially deproteinized biologic bone alone and blank control were also implanted. After transplantation, the proliferation of implanted seed cells in tissue-engineered bones was labeled by bromodeoxyuridine staining. Moreover, the changes of T-lymphocyte subpopulations, including CD3 + CD4+ and CD3 + CD8+ in peripheral blood were then detected using flow cytometry to analyze the immune rejection of tissue-engineered bone implantation based on peripheral blood CD4/CD8 ratios. RESULTS: After transplantation, the proliferation of implanted seed cells was observed in tissue-engineered bones of different groups. At different time points after transplantation, the CD4+/CD8+ ratio in peripheral blood of PDPBB + ADSCs, PDPBB + coculture, and blank control groups did not exhibit significant change. Although the CD4+/CD8+ ratio in peripheral blood of PDPBB + VECs group was significantly higher than other group at 1 week after transplantation, that of PDPBB + VECs and PDPBB + coculture group was significantly decreased at 8 week after transplantation compared with that of blank control group. CONCLUSIONS: Our results indicated that there was no significant immune rejection after transplantation of tissue-engineered bone constructed with PDPBB and coculture of ADSCs and VECs as seed cells.

[Comparative study on effectiveness of posterior-posterior triangulation technique and anteroposterior approach for arthroscopic posterior cruciate ligament reconstruction].

OBJECTIVE: To investigate the effectiveness of the posterior-posterior triangulation technique for arthroscopic posterior cruciate ligament (PCL) reconstruction by comparing with the anteroposterior approach. METHODS: Retrospective analysis was performed on 40 patients who underwent arthroscopic PCL reconstruction between February 2016 and February 2020. The PCLs were reconstructed via anteroposterior approach in 20 patients (anteroposterior approach group) and posterior-posterior triangulation technique in 20 patients (posterior-posterior triangulation technique group). There was no significant difference in gender, age, cause of injury, injury side, disease duration, preoperative International Knee Documentary Committee (IKDC) score, and Lysholm score between the two groups ( P>0.05). The operation time, surgical complications, and postoperative posterior drawer test, Lysholm score, and IKDC score were recorded and compared between the two groups. RESULTS: The operation time was (65.25±10.05) minutes in the anteroposterior approach group and (56.15±8.15) minutes in the posterior-posterior triangulation technique group, and the difference was significant ( t=3.145, P=0.003). All incisions healed by first intention, and there was no complication such as vascular and nerve injuries or infection. Patients were followed up (27.05±11.95) months in the anteroposterior approach group and (21.40±7.82) months in the posterior-posterior triangulation technique group, with no significant difference ( t=1.770, P=0.085). At last follow-up, the posterior drawer tests were positive in 4 cases (3 cases of stageⅠand 1 case of stage Ⅱ) of the anteroposterior approach group and in 1 case (stageⅠ) of the posterior-posterior triangulation technique group, showing no significant difference between the two groups ( P=0.342). At last follow-up, Lysholm score and IKDC score in both groups were significantly higher than those before operation ( P<0.05). The above functional scores in the posterior-posterior triangulation technique group were significantly higher than those in the anteroposterior approach group ( P<0.05). Imaging reexamination showed that the position, shape, and tension of the grafts were well in both groups, and the grafts were covered with the synovium in the posterior-posterior triangulation technique group, the meniscofemoral ligaments were well preserved. There was no re-rupture of the reconstructed ligament during follow-up. CONCLUSION: Compared to the anteroposterior approach, the posterior-posterior triangulation technique provides a clearer view under arthroscopy, no blind spot, sufficient operating space, and relative safety. Moreover, it is easier to retain the remnant and the meniscofemoral ligaments, and can obtain good short-term effectiveness.

A novel full endoscopic annular repair technique combined with autologous conditioned plasma intradiscal injection: a new safe serial therapeutic model for the treatment of lumbar disc herniation.

BACKGROUND: Recurrent intervertebral disc herniation and an exacerbated degenerative process have been identified as the most important factors contributing to persistent pain and disability after surgical discectomy. Defects in the annulus fibrosus remain a surgical challenge, as the preference for minimally invasive surgical approaches for lumbar microdiscectomy, surgical access, and the specifics of anatomy limit the types of devices that permit annulus fibrosus repair. Furthermore, the intervertebral disc is a relatively avascular structure, and surgical procedures can accelerate the degenerative disc process. This study aimed to evaluate the clinical safety and efficacy of a novel microdiscectomy annular repair technique combined with an autologous conditioned plasma (ACP) intradiscal injection for the treatment of lumbar disc herniation (LDH). METHODS: From July 2017 to December 2018 this study recruited 75 patients with LDH (single segment) and randomly divided these patients into the following three groups: group A, full endoscopic discectomy; group B: full endoscopic discectomy and annular repair; group C, full endoscopic discectomy annular repair and ACP intradiscal injection. The pre- and postoperative neurological function and pain status were evaluated by the visual analog scale (VAS) score and the Oswestry disability index (ODI). Patients were followed up once preoperatively, and at 1, 3, and 6 months postoperatively. RESULTS: The procedure was successfully performed in all cases. No cases required conversion to an open procedure. The preoperative symptoms were alleviated significantly after surgery. The VAS scores for lower back and lower limb pain and ODI score were significantly difference at 1 month, 3 months, 6 months post operation compared to pre-operation scores (P<0.05). For VAS scores of the lower back, the difference between group A and group C was statistically significant (A>C), as was the difference between group B and group C (B>C). CONCLUSIONS: Early results showed that the use of the novel full endoscopic annular repair technique and ACP intradiscal injection serial therapeutic model are beneficial for short term outcomes and demonstrates a reduction in symptomatic disc reherniation with low postoperative complication rates. This new serial therapeutic model may significantly improve the symptoms of postoperative lower back pain.

Construction of tissue engineering bone with the co­culture system of ADSCs and VECs on partially deproteinized biologic bone in vitro: A preliminary study.

Scaffold­based bone tissue engineering has therapeutic potential in the regeneration of osseous defects. The present study aimed to explore the adhesion and cell viability of a co­culture system composed of vascular endothelial cells PI­/Annexin V+ represents early apoptotic cells, and PI+/Annexin V+ represents late apoptotic cells (VECs) and adipose­derived stem cells (ADSCs) on partially deproteinized biologic bone (PDPBB) in vitro, and determine the optimum time period for maximum cell viability that could possibly be used for standardizing the scaffold transplant into the in vivo system. VECs and ADSCs were isolated from pregnant Sprague­Dawley rats and confirmed by immunostaining with von Willebrand factor and CD90, respectively. PDPBB was prepared using standardized protocols involving coating partially deproteinized bone with fibronectin. PDPBB was incubated in a mono­culture with VECs or ADSCs, or in a co­culture with both of these cells at a ratio of 1:1. An MTT assay was used to assess the adhesion and cell viability of VECs and ADSCs on PDPBB in the three different cultures. Scanning electron microscopy was used to observe the adhesion, cell viability and morphology of the different types of cells on PDPBB. It was observed that the absorbance of each group increased gradually and peaked on the 10th day; the highest absorbance was found for the co­cultured cells group. The difference of cell viability between each cell group was statistically significant. On the 10th day, in the co­cultured cells group, several cells adhered on the PDPBB material and a nest­like distribution morphology was observed. Therefore, the adhesion and cell viability of the co­cultured cells was higher compared with the mono­cultures of VECs or ADSCs. As cell viability was highest on the 10th day, this could be the optimal length of time for incubation and therefore could be used for in vivo experiments.

Expressions and relationship of Krüppel-like factor 15 and endothelial nitric oxide synthase in experimental deep venous thrombosis.

BACKGROUND: Deep vein thrombosis (DVT) is an early postoperative complication. Thrombosis formation, which is potentially life-threatening, seriously affects the rehabilitation of patients after surgery. We aimed to establish a C57 mouse model of DVT and to examine the changes in the expression of Krüppel-like factor 15 (KLF15) and endothelial nitric oxide synthase (eNOS) in venous wall tissues, and we also investigated the regulatory relationship of KLF15 and eNOS in the thrombin-induced human umbilical vein endothelial cell (HUVEC) injury cell model. METHODS: The DVT model was established using the inferior vena cava (IVC) stenosis method. The expression levels of KLF15 and eNOS were analyzed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In cell experiments, the expression of KLF15 and eNOS was analyzed in the model of thrombin-induced HUVEC injury with KLF15 siRNA. RESULTS: Compared to the control and sham-operated groups, KLF15 in the DVT group was upregulated, while eNOS was downregulated. The results of cell experiments revealed that KLF15 was downregulated in the thrombin+KLF15 siRNA group compared with the thrombin group. Meanwhile, eNOS was upregulated in the thrombin+KLF15 siRNA group compared with the thrombin group. These findings suggested that KLF15 regulated the expression of eNOS in the DVT model. CONCLUSIONS: We successfully constructed a DVT mouse model. In the early stage of DVT formation, KLF15 regulated the expression and inhibited the antithrombotic effect of eNOS, resulting in thrombi formation.

Repair of Bone Defects With Endothelial Progenitor Cells and Bone Marrow-Derived Mesenchymal Stem Cells With Tissue-Engineered Bone in Rabbits.

PURPOSE: This study aimed to investigate the repair of bone defects in rabbits with tissue-engineered bones using cocultured endothelial progenitor cells (EPCs) and bone marrow mesenchymal stem cells (BMSCs) as seeding cells. METHODS: Endothelial progenitor cells and BMSCs were isolated and purified from the peripheral blood and bone marrow, respectively, of New Zealand rabbits. The third passage of BMSCs was cultured alone or with EPCs. Cells were characterized using specific markers and then seeded on partially deproteinized biologic bones from pigs as a scaffold. The engineered bones were used to repair bone defects in rabbits. Hematoxylin and eosin and Masson staining were performed to examine vascularization and osteogenesis in the engineered bone. RESULTS: The cocultured EPCs and BMSCs grew well on the surface of the scaffold. Compared with monocultured BMSCs, cocultured EPCs and BMSCs promoted the formation of blood vessels and bone on the scaffold, in addition to accelerating the repair of bone defects. The collagen content was significantly increased in the scaffold with cocultured EPCs and BMSCs, compared with the scaffold seeded with mono-cultured BMSCs. CONCLUSIONS: Tissue-engineered bones seeded with cocultured EPCs and BMSCs may be used effectively for the repair of bone defects.