Research advances on stem cell-based treatments in animal studies and clinical trials of lymphedema / 中国修复重建外科杂志

OBJECTIVE@#To summarize the progress of the roles and mechanisms of various types of stem cell-based treatments and their combination therapies in both animal studies and clinical trials of lymphedema.@*METHODS@#The literature on stem cell-based treatments for lymphedema in recent years at home and abroad was extensively reviewed, and the animal studies and clinical trials on different types of stem cells for lymphedema were summarized.@*RESULTS@#Various types of stem cells have shown certain effects in animal studies and clinical trials on the treatment of lymphedema, mainly through local differentiation into lymphoid endothelial cells and paracrine cytokines with different functions. Current research focuses on two cell types, adipose derived stem cells and bone marrow mesenchymal stem cells, both of which have their own advantages and disadvantages, mainly reflected in the therapeutic effect of stem cells, the difficulty of obtaining stem cells and the content in vivo. In addition, stem cells can also play a synergistic role in combination with other treatments, such as conservative treatment, surgical intervention, cytokines, biological scaffolds, and so on. However, it is still limited to the basic research stage, and only a small number of studies have completed clinical trials.@*CONCLUSION@#Stem cells have great transformation potential in the treatment of lymphedema, but there is no unified standard in the selection of cell types, the amount of transplanted cells, and the timing of transplantation.

Mechanism and application in tissue engineering of the active ingredient of Drynariae Rhizoma promoting bone defect repair / 中国药房

Bone defect has always been a major clinical challenge because of its great difficulty and long period of treatment. Drynariae Rhizoma is a commonly used medicine in osteology and traumatology of traditional Chinese medicine， and its active ingredients（mainly flavonoids） facilitate osteoblast differentiation of bone marrow mesenchymal stem cells， osteoclast proliferation， vascular-osteogenic coupling， and inhibit osteoclast activity to promote bone mineralization， and repair and reconstruction of bone defect. As a good substitute for bone regeneration drugs， the active constituents of Drynariae Rhizoma can be loaded on scaffold materials of tissue engineering， which greatly improves the bioavailability of the drug. Meanwhile， the sustained-release microspheres also solve some problems such as sudden drug release from the scaffolds， and the composite scaffolds with active ingredient of Drynariae Rhizoma prepared by them have good ossification activity and osteoinduction， with precise bone repair effects， which meet the diverse performance requirements of bone grafts and have a promising clinical application prospect.

Reconstruction of rat calvarial defects utilizing an ultraviolet-cured hydrogel loaded with bone marrow mesenchymal stem cells / 口腔疾病防治

Objective@#To investigate the osteogenic properties of a methacrylated gelatin (GelMA) / bone marrow mesenchymal stem cells (BMSCs) composite hydrogel applied to the skull defect area of rats and to provide an experimental basis for the development of bone regeneration biomaterials.@*Methods@#This study was approved by the Animal Ethics Committee of Nanjing University. A novel photocurable composite biohydrogel was developed by constructing photoinitiators [lthium phenyl (2,4,6-trimethylbenzoyl) phosphinate, LAP], GelMA, and BMSCs. The surface morphology and elemental composition of the gel were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The compressive strength of the gel was evaluated using an electronic universal testing machine. After in vitro culture for 1, 2, and 5 days, the proliferation of the BMSCs in the hydrogels was assessed using a CCK-8 assay, and their survival and morphology were examined through confocal microscopy. A 5 mm critical bone deficiency model was generated in a rat skull. The group receiving composite hydrogel treatment was referred to as the GelMA/BMSCs group, whereas the untreated group served as the control group. At the 4th and 8th weeks, micro-CT scans were taken to measure the bone defect area and new bone index, while at the 8th week, skull samples from the defect area were subjected to H&E staining, van Gieson staining, and Goldner staining to evaluate the quality of bone regeneration and new bone formation.@*Results@#SEM observed that the solidified GelMA showed a 3D spongy gel network with uniform morphology, the porosity of GelMA was 73.41% and the pore size of GelMA was (28.75 ± 7.13) μm. EDX results showed that C and O were evenly distributed in the network macroporous structure of hydrogel. The hydrogel compression strength was 152 kPa. On the 5th day of GelMA/BMSCs culture, the cellular morphology transitioned from oval to spindle shaped under microscopic observation, accompanied by a significant increase in cell proliferation (159.4%, as determined by the CCK-8 assay). At 4 weeks after surgery, a 3D reconstructed micro-CT image revealed a minimal reduction in bone defect size within the control group and abundant new bone formation in the GelMA/BMSCs group. At 8 weeks after surgery, no significant changes were observed in the control group's bone defect area, with only limited evidence of new bone growth; however, substantial healing of skull defects was evident in the GelMA/BMSCs group. Quantitative analysis at both the 4- and 8-week examinations indicated significant improvements in the new bone volume (BV), new bone volume/total bone volume (BV/TV), bone surface (BS), and bone surface/total bone volume (BS/TV) in the GelMA/BMSCs group compared to those in the control group (P<0.05). Histological staining showed continuous and dense formation of bone tissue within the defects in the GelMA/BMSCs group and only sporadic formation of new bone, primarily consisting of fibrous connective tissue, at the defect edge in the control group.@*Conclusion@#Photocuring hydrogel-based stem cell therapy exhibits favorable biosafety profiles and has potential for clinical application by inducing new bone formation and promoting maturation within rat skull defects.

3D printed Mg-incorporated polycaprolactone scaffolds for repairing rat skull defects / 口腔疾病防治

Objective@#To evaluate the bone repair effect of 3D-printed magnesium (Mg)-loaded polycaprolactone (PCL) scaffolds in a rat skull defect model.@*Methods@#PCL scaffolds mixed with Mg microparticles were prepared by using 3D printing technology, as were pure PCL scaffolds. The surface morphologies of the two scaffolds were observed by scanning electron microscopy (SEM), and the surface elemental composition was analyzed via energy dispersive spectroscopy (EDS). The physical properties of the scaffolds were characterized through contact angle measurements and an electronic universal testing machine. This study has been reviewed and approved by the Ethics Committee. A critical size defect model was established in the skull of 15 Sprague-Dawley (SD) rats, which were divided into the PCL group, PCL-Mg group, and untreated group, with 5 rats in each group. Micro-CT scanning was performed to detect and analyze skull defect healing at 4 and 8 weeks after surgery, and samples from the skull defect area and major organs of the rats were obtained for histological staining at 8 weeks after surgery.@*Results@#The scaffolds had a pore size of (480 ± 25) μm, a fiber diameter of (300 ± 25) μm, and a porosity of approximately 66%. The PCL-Mg scaffolds contained 1.0 At% Mg, indicating successful incorporation of Mg microparticles. The contact angle of the PCL-Mg scaffolds was 68.97° ± 1.39°, indicating improved wettability compared to that of pure PCL scaffolds. Additionally, compared with that of pure PCL scaffolds, the compressive modulus of the PCL-Mg scaffolds was (57.37 ± 8.33) MPa, demonstrating enhanced strength. The PCL-Mg group exhibited the best bone formation behavior in the skull defect area compared with the control group and PCL group at 4 and 8 weeks after surgery. Moreover, quantitative parameters, such as bone volume (BV), bone volume/total volume (BV/TV), bone surface (BS), bone surface/total volume (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and bone mineral density (BMD), of skull defects were better than those in the other groups, indicating the best bone regeneration effect. H&E, Goldner, and VG staining revealed more mineralized new bone formation in the PCL-Mg group than in the other groups, and H&E staining of the major organs revealed good biosafety of the material.@*Conclusion@#PCL-Mg scaffolds can promote the repair of bone defects and have clinical potential as a new scaffold material for the repair of maxillofacial bone defects.

Advances in corneal stromal regeneration and repair / 国际眼科杂志(Guoji Yanke Zazhi)

Corneal stroma is a significant part of the cornea and plays a significant role in the eye's refractive system. Although corneal transplantation is now the most effective treatment for corneal stromal disease, its advancement has been constrained by a shortage of donors, the need for prolonged immunosuppressive medicine to prevent rejection, and low graft survival rates. An alternate strategy is to use the corneal stroma's natural capacity for regeneration to create the ideal conditions for the collagenous extracellular matrix of the stroma to self-renew. However, it is challenging to replicate the intricate ultrastructure of the corneal stroma in vitro. Regenerative medicine has so been used to address these issues. These approaches refer to numerous disciplines, including stem cell-induced differentiation, tissue engineering and gene editing. This article provides potential directions for the future clinical applications of corneal stromal regeneration and repair while summarizing pertinent techniques, research progress, and issues.

Unlocking the potential of amorphous calcium carbonate: A star ascending in the realm of biomedical application

Calcium-based biomaterials have been intensively studied in the field of drug delivery owing to their excellent biocompatibility and biodegradability. Calcium-based materials can also deliver contrast agents, which can enhance real-time imaging and exert a Ca2+-interfering therapeutic effect. Based on these characteristics, amorphous calcium carbonate (ACC), as a brunch of calcium-based biomaterials, has the potential to become a widely used biomaterial. Highly functional ACC can be either discovered in natural organisms or obtained by chemical synthesis However, the standalone presence of ACC is unstable in vivo. Additives are required to be used as stabilizers or core-shell structures formed by permeable layers or lipids with modified molecules constructed to maintain the stability of ACC until the ACC carrier reaches its destination. ACC has high chemical instability and can produce biocompatible products when exposed to an acidic condition in vivo, such as Ca2+ with an immune-regulating ability and CO2 with an imaging-enhancing ability. Owing to these characteristics, ACC has been studied for self-sacrificing templates of carrier construction, targeted delivery of oncology drugs, immunomodulation, tumor imaging, tissue engineering, and calcium supplementation. Emphasis in this paper has been placed on the origin, structural features, and multiple applications of ACC. Meanwhile, ACC faces many challenges in clinical translation, and long-term basic research is required to overcome these challenges. We hope that this study will contribute to future innovative research on ACC.

Research progress on dedifferentiated fat cells and their application in oral and maxillofacial bone tissue engineering / 口腔疾病防治

@#The identification of suitable seed cells represents a critical scientific problem to be solved in the field of oral and maxillofacial bone tissue regeneration. The application of adipose-derived stem cells (ASCs) in tissue and organ repair and regeneration has been studied extensively. In recent years, dedifferentiated fat (DFAT) cells have also shown broad application prospects in the field of bone tissue engineering. DFAT cells express stem cell-related markers and have the potential to differentiate into adipocytes, osteoblasts, chondrocytes, nerve cells, cardiomyocytes and endothelial cells. In addition, DFAT cells also have the advantages of minimally invasive acquisition, strong proliferation and high homogeneity. Currently, all studies involving the application of DFAT cells in scaffold-based and scaffold-free bone tissue engineering can confirm their effectiveness in promoting bone regeneration. However, cytological research still faces some challenges, including relatively low cell culture purity, unclear phenotypic characteristics and undefined dedifferentiation mechanisms. It is believed that with the continuous development and improvement of isolation, culture, identification and directional induction of osteogenic differentiation methods, DFAT cells are expected to become excellent seed cells in the field of oral and maxillofacial bone tissue engineering in the future.

Novel Therapy for Acquired Tracheomalacia with a Tissue-Engineered Extraluminal Tracheal Splint and Autologous Mesenchymal-Derived Chondrocytes

Abstract Introduction Acquired tracheomalacia (ATM) is characterized by a loss of structural strength of the tracheal framework, resulting in airway collapse during breathing. Near half of the patients undergoing prolonged invasive mechanical ventilation will suffer tracheal lesions. Treatment for ATM includes external splinting with rib grafts, prosthetic materials, and tracheal resection. Failure in the use of prosthetic materials has made reconsidering natural origin scaffolds and tissue engineering as a suitable alternative. Objective To restore adequate airway patency in an ovine model with surgicallyinduced ATM employing a tissue-engineered extraluminal tracheal splint (TE-ETS). Methods In the present prospective pilot study, tracheal rings were partially resected to induce airway collapse in 16 Suffolk sheep (Ovis aries). The TE-ETS was developed with autologous mesenchymal-derived chondrocytes and allogenic decellularized tracheal segments and was implanted above debilitated tracheal rings. The animals were followed-up at 8, 12, and 16 weeks and at 1-year postinsertion. Flexible tracheoscopies were performed at each stage. After sacrifice, a histopathological study of the trachea and the splint were performed. Results The TE-ETS prevented airway collapse for 16 weeks and up to 1-year postinsertion. Tracheoscopies revealed a noncollapsing airway during inspiration. Histopathological analyses showed the organization of mesenchymal-derived chondrocytes in lacunae, the proliferation of blood vessels, and recovery of epithelial tissue subjacent to the splint. Splints without autologous cells did not prevent airway collapse. Conclusion It is possible to treat acquired tracheomalacia with TE-ETS without further surgical removal since it undergoes physiological degradation. The present study supports the development of tissue-engineered tracheal substitutes for airway disease.

Culture of rat mesenchymal stem cells on PHBV-PCL scaffolds: analysis of conditioned culture medium by FT Raman spectroscopy / Cultivo de células-tronco mesenquimais de rato sobre arcabouços de PHBV-PCL: análise do meio de cultura condicionado por espectroscopia de FT-Raman

Mesenchymal stem cells (MSCs) have great potential for application in cell therapy and tissue engineering procedures because of their plasticity and capacity to differentiate into different cell types. Given the widespread use of MSCs, it is necessary to better understand some properties related to osteogenic differentiation, particularly those linked to biomaterials used in tissue engineering. The aim of this study was to develop an analysis method using FT-Raman spectroscopy for the identification and quantification of biochemical components present in conditioned culture media derived from MSCs with or without induction of osteogenic differentiation. All experiments were performed between passages 3 and 5. For this analysis, MSCs were cultured on scaffolds composed of bioresorbable poly(hydroxybutyrate co-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) polymers. MSCs (GIBCO®) were inoculated onto the pure polymers and 75:25 PHBV/PCL blend (dense and porous samples). The plate itself was used as control. The cells were maintained in DMEM (with low glucose) containing GlutaMAX® and 10% FBS at 37ºC with 5% CO2 for 21 days. The conditioned culture media were collected and analyzed to probe for functional groups, as well as possible molecular variations associated with cell differentiation and metabolism. The method permitted to identify functional groups of specific molecules in the conditioned medium such as cholesterol, phosphatidylinositol, triglycerides, beta-subunit polypeptides, amide regions and hydrogen bonds of proteins, in addition to DNA expression. In the present study, FT-Raman spectroscopy exhibited limited resolution since different molecules can express similar or even the same stretching vibrations, a fact that makes analysis difficult. There were no variations in the readings between the samples studied. In conclusion, FT-Raman spectroscopy did not meet expectations under the conditions studied.

As células-tronco mesenquimais (MSCs) possuem grande potencial para aplicação em procedimentos terapêuticos ligados a terapia celular e engenharia de tecidos, considerando-se a plasticidade e capacidade de formação em diferentes tipos celulares por elas. Dada a abrangência no emprego das MSCs, há necessidade de se compreender melhor algumas propriedades relacionadas à diferenciação osteogênica, particularmente liga à biomateriais usados em engenharia de tecidos. Este projeto objetiva o desenvolvimento de uma metodologia de análise empregando-se a FT-Raman para identificação e quantificação de componentes bioquímicos presentes em meios de cultura condicionados por MSCs, com ou sem indução à diferenciação osteogênica. Todos os experimentos foram realizados entre as passagens 3 e 5. Para essas análises, as MSCs foram cultivadas sobre arcabouços de polímeros biorreabsorvíveis de poli (hidroxibutirato-co-hidroxivalerato) (PHBV) e o poli (ε-caprolactona) (PCL). As MSCs (GIBCO®) foram inoculadas nos polímeros puros e na mistura 75:25 de PHBV / PCL (amostras densas e porosas). As células foram mantidas em DMEM (com baixa glicose) contendo GlutaMAX® e 10% de SFB a 37oC com 5% de CO2 por 21 dias. A própria placa foi usada como controle. Os meios de cultura condicionados foram coletados e analisadas em FT-Raman para sondagem de grupos funcionais, bem como possíveis variações moleculares associadas com a diferenciação e metabolismo celular. Foi possível discernir grupos funcionais de moléculas específicas no meio condicionado, como colesterol, fosfatidilinositol, triglicerídeos, forma Beta de polipeptídeos, regiões de amida e ligações de hidrogênio de proteínas, além da expressão de DNA. Na presente avaliação, a FT-Raman apresentou como uma técnica de resolução limitada, uma vez que modos vibracionais de estiramento próximos ou mesmo iguais podem ser expressos por moléculas diferente, dificultando a [...].

Culture of rat mesenchymal stem cells on PHBV-PCL scaffolds: analysis of conditioned culture medium by FT-Raman spectroscopy

Abstract Mesenchymal stem cells (MSCs) have great potential for application in cell therapy and tissue engineering procedures because of their plasticity and capacity to differentiate into different cell types. Given the widespread use of MSCs, it is necessary to better understand some properties related to osteogenic differentiation, particularly those linked to biomaterials used in tissue engineering. The aim of this study was to develop an analysis method using FT-Raman spectroscopy for the identification and quantification of biochemical components present in conditioned culture media derived from MSCs with or without induction of osteogenic differentiation. All experiments were performed between passages 3 and 5. For this analysis, MSCs were cultured on scaffolds composed of bioresorbable poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(-caprolactone) (PCL) polymers. MSCs (GIBCO®) were inoculated onto the pure polymers and 75:25 PHBV/PCL blend (dense and porous samples). The plate itself was used as control. The cells were maintained in DMEM (with low glucose) containing GlutaMAX® and 10% FBS at 37oC with 5% CO2 for 21 days. The conditioned culture media were collected and analyzed to probe for functional groups, as well as possible molecular variations associated with cell differentiation and metabolism. The method permitted to identify functional groups of specific molecules in the conditioned medium such as cholesterol, phosphatidylinositol, triglycerides, beta-subunit polypeptides, amide regions and hydrogen bonds of proteins, in addition to DNA expression. In the present study, FT-Raman spectroscopy exhibited limited resolution since different molecules can express similar or even the same stretching vibrations, a fact that makes analysis difficult. There were no variations in the readings between the samples studied. In conclusion, FT-Raman spectroscopy did not meet expectations under the conditions studied.

Resumo As células-tronco mesenquimais (MSCs) possuem grande potencial para aplicação em procedimentos terapêuticos ligados a terapia celular e engenharia de tecidos, considerando-se a plasticidade e capacidade de formação em diferentes tipos celulares por elas. Dada a abrangência no emprego das MSCs, há necessidade de se compreender melhor algumas propriedades relacionadas à diferenciação osteogênica, particularmente liga à biomateriais usados em engenharia de tecidos. Este projeto objetiva o desenvolvimento de uma metodologia de análise empregando-se a FT-Raman para identificação e quantificação de componentes bioquímicos presentes em meios de cultura condicionados por MSCs, com ou sem indução à diferenciação osteogênica. Todos os experimentos foram realizados entre as passagens 3 e 5. Para essas análises, as MSCs foram cultivadas sobre arcabouços de polímeros biorreabsorvíveis de poli (hidroxibutirato-co-hidroxivalerato) (PHBV) e o poli (-caprolactona) (PCL). As MSCs (GIBCO®) foram inoculadas nos polímeros puros e na mistura 75:25 de PHBV / PCL (amostras densas e porosas). As células foram mantidas em DMEM (com baixa glicose) contendo GlutaMAX® e 10% de SFB a 37oC com 5% de CO2 por 21 dias. A própria placa foi usada como controle. Os meios de cultura condicionados foram coletados e analisadas em FT-Raman para sondagem de grupos funcionais, bem como possíveis variações moleculares associadas com a diferenciação e metabolismo celular. Foi possível discernir grupos funcionais de moléculas específicas no meio condicionado, como colesterol, fosfatidilinositol, triglicerídeos, forma Beta de polipeptídeos, regiões de amida e ligações de hidrogênio de proteínas, além da expressão de DNA. Na presente avaliação, a FT-Raman apresentou como uma técnica de resolução limitada, uma vez que modos vibracionais de estiramento próximos ou mesmo iguais podem ser expressos por moléculas diferente, dificultando a análise. Não houve variações nas leituras entre as amostras estudadas, concluindo-se que a FT-Raman não atendeu às expectativas nas condições estudadas.

Culture of rat mesenchymal stem cells on PHBV-PCL scaffolds: analysis of conditioned culture medium by FT-Raman spectroscopy / Cultivo de células-tronco mesenquimais de rato sobre arcabouços de PHBV-PCL: análise do meio de cultura condicionado por espectroscopia de FT-Raman

Abstract Mesenchymal stem cells (MSCs) have great potential for application in cell therapy and tissue engineering procedures because of their plasticity and capacity to differentiate into different cell types. Given the widespread use of MSCs, it is necessary to better understand some properties related to osteogenic differentiation, particularly those linked to biomaterials used in tissue engineering. The aim of this study was to develop an analysis method using FT-Raman spectroscopy for the identification and quantification of biochemical components present in conditioned culture media derived from MSCs with or without induction of osteogenic differentiation. All experiments were performed between passages 3 and 5. For this analysis, MSCs were cultured on scaffolds composed of bioresorbable poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) polymers. MSCs (GIBCO®) were inoculated onto the pure polymers and 75:25 PHBV/PCL blend (dense and porous samples). The plate itself was used as control. The cells were maintained in DMEM (with low glucose) containing GlutaMAX® and 10% FBS at 37oC with 5% CO2 for 21 days. The conditioned culture media were collected and analyzed to probe for functional groups, as well as possible molecular variations associated with cell differentiation and metabolism. The method permitted to identify functional groups of specific molecules in the conditioned medium such as cholesterol, phosphatidylinositol, triglycerides, beta-subunit polypeptides, amide regions and hydrogen bonds of proteins, in addition to DNA expression. In the present study, FT-Raman spectroscopy exhibited limited resolution since different molecules can express similar or even the same stretching vibrations, a fact that makes analysis difficult. There were no variations in the readings between the samples studied. In conclusion, FT-Raman spectroscopy did not meet expectations under the conditions studied.

Resumo As células-tronco mesenquimais (MSCs) possuem grande potencial para aplicação em procedimentos terapêuticos ligados a terapia celular e engenharia de tecidos, considerando-se a plasticidade e capacidade de formação em diferentes tipos celulares por elas. Dada a abrangência no emprego das MSCs, há necessidade de se compreender melhor algumas propriedades relacionadas à diferenciação osteogênica, particularmente liga à biomateriais usados em engenharia de tecidos. Este projeto objetiva o desenvolvimento de uma metodologia de análise empregando-se a FT-Raman para identificação e quantificação de componentes bioquímicos presentes em meios de cultura condicionados por MSCs, com ou sem indução à diferenciação osteogênica. Todos os experimentos foram realizados entre as passagens 3 e 5. Para essas análises, as MSCs foram cultivadas sobre arcabouços de polímeros biorreabsorvíveis de poli (hidroxibutirato-co-hidroxivalerato) (PHBV) e o poli (ε-caprolactona) (PCL). As MSCs (GIBCO®) foram inoculadas nos polímeros puros e na mistura 75:25 de PHBV / PCL (amostras densas e porosas). As células foram mantidas em DMEM (com baixa glicose) contendo GlutaMAX® e 10% de SFB a 37oC com 5% de CO2 por 21 dias. A própria placa foi usada como controle. Os meios de cultura condicionados foram coletados e analisadas em FT-Raman para sondagem de grupos funcionais, bem como possíveis variações moleculares associadas com a diferenciação e metabolismo celular. Foi possível discernir grupos funcionais de moléculas específicas no meio condicionado, como colesterol, fosfatidilinositol, triglicerídeos, forma Beta de polipeptídeos, regiões de amida e ligações de hidrogênio de proteínas, além da expressão de DNA. Na presente avaliação, a FT-Raman apresentou como uma técnica de resolução limitada, uma vez que modos vibracionais de estiramento próximos ou mesmo iguais podem ser expressos por moléculas diferente, dificultando a análise. Não houve variações nas leituras entre as amostras estudadas, concluindo-se que a FT-Raman não atendeu às expectativas nas condições estudadas.

Research on Runx2 gene induced differentiation of human amniotic mesenchymal stem cells into ligament fibroblasts in vitro and promotion of tendon-bone healing in rabbits / 中国修复重建外科杂志

OBJECTIVE@#To investigate whether the Runx2 gene can induce the differentiation of human amniotic mesenchymal stem cells (hAMSCs) to ligament fibroblasts in vitro and promote the tendon-bone healing in rabbits.@*METHODS@#hAMSCs were isolated from the placentas voluntarily donated from healthy parturients and passaged, and then identified by flow cytometric identification. Adenoviral vectors carrying Runx2 gene (Ad-Runx2) and empty vector adenovirus (Ad-NC) were constructed and viral titer assay; then, the 3rd generation hAMSCs were transfected with Ad-Runx2 (Ad-Runx2 group) or Ad-NC (Ad-NC group). The real-time fluorescence quantitative PCR and Western blot were used to detect Runx2 gene and protein expression to verify the effectiveness of Ad-Runx2 transfection of hAMSCs; and at 3 and 7 days after transfection, real-time fluorescence quantitative PCR was further used to detect the expressions of ligament fibroblast-related genes [vascular endothelial growth factor (VEGF), collagen type Ⅰ, Fibronectin, and Tenascin-C]. The hAMSCs were used as a blank control group. The hAMSCs, hAMSCs transfected with Ad-NC, and hAMSCs were mixed with Matrigel according to the ratio of 1 : 1 and 1 : 2 to construct the cell-scaffold compound. Cell proliferation was detected by cell counting kit 8 (CCK-8) assay, and the corresponding cell-scaffold compound with better proliferation were taken for subsequent animal experiments. Twelve New Zealand white rabbits were randomly divided into 4 groups of sham operation group (Sham group), anterior cruciate ligament reconstruction group (ACLR group), anterior cruciate ligament reconstruction+hAMSCs transfected with Ad-NC-scaffold compound group (Ad-NC group), and anterior cruciate ligament reconstruction+hAMSCs transfected with Ad-Runx2-scaffold compound group (Ad-Runx2 group), with 3 rabbits in each group. After preparing the ACL reconstruction model, the Ad-NC group and the Ad-Runx2 group injected the optimal hAMSCs-Matrigel compunds into the bone channel correspondingly. The samples were taken for gross, histological (HE staining and sirius red staining), and immunofluorescence staining observation at 1 month after operation to evaluate the inflammatory cell infiltration as well as collagen and Tenascin-C content in the ligament tissues.@*RESULTS@#Flow cytometric identification of the isolated cells conformed to the phenotypic characteristics of MSCs. The Runx2 gene was successfully transfected into hAMSCs. Compared with the Ad-NC group, the relative expressions of VEGF and collagen type Ⅰ genes in the Ad-Runx2 group significantly increased at 3 and 7 days after transfection ( P<0.05), Fibronectin significantly increased at 3 days ( P<0.05), and Tenascin-C significantly increased at 3 days and decreased at 7 days ( P<0.05). CCK-8 detection showed that there was no significant difference ( P>0.05) in the cell proliferation between groups and between different time points after mixed culture of two ratios. So the cell-scaffold compound constructed in the ratio of 1∶1 was selected for subsequent experiments. Animal experiments showed that at 1 month after operation, the continuity of the grafted tendon was complete in all groups; HE staining showed that the tissue repair in the Ad-Runx2 group was better and there were fewer inflammatory cells when compared with the ACLR group and the Ad-NC group; sirius red staining and immunofluorescence staining showed that the Ad-Runx2 group had more collagen typeⅠ and Ⅲ fibers, tending to form a normal ACL structure. However, the fluorescence intensity of Tenascin-C protein was weakening when compared to the ACLR and Ad-NC groups.@*CONCLUSION@#Runx2 gene transfection of hAMSCs induces directed differentiation to ligament fibroblasts and promotes tendon-bone healing in reconstructed anterior cruciate ligament in rabbits.

A dual-crosslinked injectable hydrogel derived from muscular decellularized matrix promoting myoblasts proliferation and myogenic differentiation / 中国修复重建外科杂志

OBJECTIVE@#To investigate the feasibility of a dual-crosslinked injectable hydrogel derived from acellular musclar matrix (AMM) for promoting myoblasts proliferation and myogenic differentiation.@*METHODS@#Firstly, hyaluronic acid was oxidized with NaIO 4 and methylated to prepare methacrylamidated oxidized hyaluronic acid (MOHA). Then, AMM obtained by washing enzymatically treated muscle tissue was aminolyzed to prepare aminated AMM (AAMM). MOHA hydrogel and AAMM were crosslinked using Schiff based reaction and UV radiation to prepare a dual-crosslinked MOHA/AAMM injectable hydrogel. Fourier transform infrared spectroscopy (FTIR) was used to characterize MOHA, AAMM, and MOHA/AAMM hydrogels. The injectability of MOHA/AAMM hydrogel were evaluated by manual injection, and the gelation performance was assessed by UV crosslinking. The rheological properties and Young's modulus of the hydrogel were examined through mechanical tests. The degradation rate of the hydrogel was assessed by immersing it in PBS. The active components of the hydrogel were verified using immunofluorescence staining and ELISA assay kits. The promotion of cell proliferation by the hydrogel was tested using live/dead staining and cell counting kit 8 (CCK-8) assays after co-culturing with C2C12 myoblasts for 9 days. The effect of the hydrogel on myogenic differentiation was evaluated by immunofluorescence staining and real time quantitative polymerase chain reaction (RT-qPCR).@*RESULTS@#FTIR spectra confirmed the successful preparation of MOHA/AAMM hydrogel. The hydrogel exhibited good injectability and gelation ability. Compared to MOHA hydrogel, MOHA/AAMM hydrogel exhibited higher viscosity and Young's modulus, a reduced degradation rate, and contained a higher amount of collagen (including collagen type Ⅰ and collagen type Ⅲ) as well as bioactive factors (including epidermal growth factor, fibroblast growth factor 2, vascular endothelial growth factor, and insulin-like growth factor 1). The live/dead cell staining and CCK-8 assay indicated that with prolonged incubation time, there was a significant increase in viable cells and a decrease in dead cells in the C2C12 myoblasts within the MOHA/AAMM hydrogel. Compared with MOHA hydrogel, the difference was significant at each time point ( P<0.05). Immunofluorescence staining and RT-qPCR analysis demonstrated that the deposition of IGF-1 and expression levels of myogenic-related genes (including Myogenin, Troponin T, and myosin heavy chain) in the MOHA/AAMM group were significantly higher than those in the MOHA group ( P<0.05).@*CONCLUSION@#The MOHA/AAMM hydrogel prepared based on AMM can promote myoblasts proliferation and myogenic differentiation, providing a novel dual-crosslinked injectable hydrogel for muscle tissue engineering.

Bone/cartilage immunomodulating hydrogels: construction strategies and applications / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress in the construction strategy and application of bone/cartilage immunomodulating hydrogels.@*METHODS@#The literature related to bone/cartilage immunomodulating hydrogels at home and abroad in recent years was reviewed and summarized from the immune response mechanism of different immune cells, the construction strategy of immunomodulating hydrogels, and their practical applications.@*RESULTS@#According to the immune response mechanism of different immune cells, the biological materials with immunoregulatory effect is designed, which can regulate the immune response of the body and thus promote the regeneration of bone/cartilage tissue. Immunomodulating hydrogels have good biocompatibility, adjustability, and multifunctionality. By regulating the physical and chemical properties of hydrogel and loading factors or cells, the immune system of the body can be purposively regulated, thus forming an immune microenvironment conducive to osteochondral regeneration.@*CONCLUSION@#Immunomodulating hydrogels can promote osteochondral repair by affecting the immunomodulation process of host organs or cells. It has shown a wide application prospect in the repair of osteochondral defects. However, more data support from basic and clinical experiments is needed for this material to further advance its clinical translation process.

Preparation of functional polyhydroxyalkanoate microspheres and their antibacterial activity and osteogenic effect evaluation / 中国修复重建外科杂志

OBJECTIVE@#To construct polyhydroxyalkanoate (PHA) microspheres loaded with bone morphogenetic protein 2 (BMP-2) and human β-defensin 3 (HBD3), and evaluate the antibacterial activity of microspheres and the effect of promoting osteogenic differentiation, aiming to provide a new option of material for bone tissue engineering.@*METHODS@#The soybean lecithin (SL)-BMP-2 and SL-HBD3 were prepared by SL-mediated introduction of growth factors into polyesters technology, and the functional microsphere (f-PMS) containing BMP-2 and HBD3 were prepared by microfluidic technology, while pure microsphere (p-PMS) was prepared by the same method as the control. The morphology of microspheres was observed by scanning electron microscopy and the water absorption was detected; the release curves of BMP-2 and HBD3 in f-PMS were detected by ELISA kit. The antibacterial effect of microspheres in Staphylococcus aureus and Escherichia coli was tested with the LIVE/DEADTM BacLightTM bacterial staining kit; the biocompatibility of microspheres was tested using Transwell and cell counting kit 8 (CCK-8). The effect of microspheres on osteogenic differentiation was determined by collagen type Ⅰ (COL-1) immunofluorescence staining and alkaline phosphatase (ALP) concentration.@*RESULTS@#In this experiment, the f-PMS and p-PMS were successfully constructed. Morphological characteristics showed that p-PMS surface was rough and distributed with micropores of 1-3 μm, while f-PMS surface was smooth and existed white granular material. There was no significant difference in water absorption between the two groups (P>0.05). The release curves of BMP-2 and HBD3 in the f-PMS and p-PMS were basically the same, showing both early sudden release and late slow release. The antibacterial activity of f-PMS was significantly higher than that of p-PMS in the test that against Staphylococcus aureus and Escherichia coli (P<0.05), but there was no significant difference in biocompatibility between the two groups (P>0.05). The results of osteogenic differentiation of human BMSCs showed that the fluorescence intensity of osteogenic specific protein COL-1 of f-PMS was significantly higher than that in p-PMS, and the activity of ALP in f-PMS was also significantly higher than that in p-PMS (P<0.05).@*CONCLUSION@#The p-PHA have good antibacterial activity and biocompatibility, and can effectively promote the osteogenic differentiation of human BMSCs, which is expected to be applied to bone tissue engineering in the future.

Research progress on medical devices of polyhydroxyalkanoate in orthopedics / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of natural biomaterial polyhydroxyalkanoate (PHA) in orthopedics.@*METHODS@#The literature concerning PHA devices for bone defects, bone repair, and bone neoplasms, respectively, in recent years was extensively consulted. The three aspects of the advantages of PHA in bone repair, the preparation of PHA medical devices for bone repair and their application in orthopedics were discussed.@*RESULTS@#Due to excellent biodegradability, biocompatibility, and potential osteoinduction, PHA is a kind of good bone repair material. In addition to the traditional PHA medical implants, the use of electrostatic spinning and three-dimensional printing can be designed to various functional PHA medical devices, in order to meet the orthopedic clinical demands, including the bone regeneration, minimally invasive bone tissue repair by injection, antibacterial bone repair, auxiliary establishment of three-dimensional bone tumor model, directed osteogenic differentiation of stem cells, etc.@*CONCLUSION@#At present, PHA is a hotspot of biomaterials for translational medicine in orthopedics. Although they have not completely applied in the clinic, the advantages of repair in bone defects have been gradually reflected in tissue engineering, showing an application prospect in orthopedics.

Research progress on biocomposites based on bioactive glass / 生物医学工程学杂志

Bioactive glass (BG) has been widely used in the preparation of artificial bone scaffolds due to its excellent biological properties and non-cytotoxicity, which can promote bone and soft tissue regeneration. However, due to the brittleness, poor mechanical strength, easy agglomeration and uncontrollable structure of glass material, its application in various fields is limited. In this regard, most current researches mainly focus on mixing BG with organic or inorganic materials by freeze-drying method, sol-gel method, etc., to improve its mechanical properties and brittleness, so as to increase its clinical application and expand its application field. This review introduces the combination of BG with natural organic materials, metallic materials and non-metallic materials, and demonstrates the latest technology and future prospects of BG composite materials through the development of scaffolds, injectable fillers, membranes, hydrogels and coatings. The previous studies show that the addition of BG improves the mechanical properties, biological activity and regeneration potential of the composites, and broadens the application of BG in the field of bone tissue engineering. By reviewing the recent BG researches on bone regeneration, the research potential of new materials is demonstrated, in order to provide a reference for future related research.

Adipose tissue-derived stem cells as a therapeutic strategy for enterocutaneous fistula: an experimental model study

ABSTRACT Purpose: Enterocutaneous fistula (ECF) is a condition in which there is an abnormal connection between the intestinal tract and the skin. It can lead to high morbidity and mortality rates despite the availability of therapeutic options. Stem cells have emerged as a potential strategy to treat ECF. This study aimed to evaluate the effect of adipose tissue-derived stem cells (ASC) on ECF in an experimental model. Methods: ECF was induced in 21 Wistar rats, and after one month, they were divided into three groups: control group (C), culture medium without ASC group (CM), and allogeneic ASC group (ASC). After 30 days, the animals underwent macroscopic analysis of ECF diameter and histopathological analysis of inflammatory cells, tissue fibrosis, and vascular density. Results: The study found a 55% decrease in the ECF diameter in the ASC group (4.5 ± 1.4 mm) compared to the control group (10.0 ± 2.1 mm, p = 0.001) and a 59.1% decrease in the CM group (11.0 ± 4.3 mm, p = 0.003). The fibrosis score in the ASC group was 20.9% lower than the control group (p = 0.03). There were no significant differences in inflammation scores among the three groups. Conclusions: This study suggests that ASC treatment can reduce ECF diameter, and reduction in tissue fibrosis may be a related mechanism. Further studies are needed to understand the underlying mechanisms fully.

Preparation and Performance of Three-Dimensional Silk FibroinScaffolds with Different Matrix Stiffness / 医用生物力学

Objective After hydrogen bonding between collagen ( COL) and silk fibroin ( SF ) at different concentrations, a composite scaffold with adjustable stiffness was prepared by combining with gel system, and its physical and chemical properties were characterized. Methods SF with different qualities was dissolved in sodium alginate (SA) solution, then COL solution at different concentration and calcium carbonate ( CaCO3 ) powder were added. The hydrogels of SC1, SC2, and SC3 groups were obtained by taking out the mixed solution and adding some gluconic acid lactone ( GDL) powder, and different SF scaffolds were obtained after freeze drying. Results The SF scaffolds with adjustable stiffness were successfully prepared. The compression moduli of SC1, SC2, and SC3 groups were (17. 31±2. 73), (24. 12±1. 81), (32. 54±1. 81) kPa, respectively. The innerstructure of the scaffolds was observed. From SC1 group to SC3 group, pores of the scaffolds were smaller and fewer, and hydrophilicity of the materials become better and better. Conclusions Three-dimensional ( 3D) porous scaffolds with different matrix stiffness can be prepared by changing the concentration of SF and COL solution. The concentration of SF and COL is proportional to the compression modulus, water absorption, water retention and swelling rate of SF scaffolds, while inversely proportional to porosity. The findings of this study are expected to provide theoretical guidance for construction of scaffolds with appropriate matrix stiffness for inducing osteogenic differentiation of mesenchymal stem cells

In vivo transplantation of eye organoids and application of tissue engineering scaffolds / 器官移植

Eye organoid refers to a structure that possesses resembling cell types and functions to intraocular tissues, which is induced by stem cells in vitro. Transplanting it into the body for eye repair and regeneration is one of the key research directions in regenerative medicine, which also provides a novel direction and strategy for the treatment of major blinding diseases. As a carrier of biological tissue or cell growth, tissue engineering scaffold could support in vivo transplantation of eye organoids and promote their maturation. Organic combination of eye organoids and tissue engineering is a critical approach to realize in vivo integration of eye organoids and reconstruct corresponding structures and functions. In this review, the latest research status of eye organoids and in vivo transplantation were summarized, and relevant studies of tissue engineering scaffold-assisted eye organoid transplantation were highlighted, aiming to provide ideas and reference for subsequent inter-disciplinary research of eye organoids and tissue engineering.