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.

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 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.

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.

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.

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.

Desenvolvimento de uma matriz acelular de pele tilápia para tratamento de feridas: Um estudo experimental / Development of acellular tilapia skin matrix for wound treatment: An experimental study

OBJETIVO: Produzir um scaffold baseado em matriz extracelular (SMEC) biocompatível, atóxico e estéril, para tratamento de queimaduras e feridas. Explorou-se a utilização da pele de tilápia como alternativa, ressaltando suas propriedades semelhantes à pele humana e sua aplicação bem-sucedida em diferentes áreas médicas. MÉTODO: Descreve o processo de preparação dos SMEC de pele de tilápia, incluindo etapas de desengorduramento, descontaminação, descelularização e irradiação por raios gama a 25kGy para esterilização. São realizados testes laboratoriais para avaliar a toxicidade celular in vitro pelo método do MTT, análises histológicas com coloração de hematoxilina-eosina, análises microbiológicas e de quantificação de DNA. RESULTADOS: Destacam que os SMEC produzidos foram descelularizados de maneira eficaz, preservando a matriz extracelular e mostrando-se não citotóxicos. Além disso, a análise microbiológica evidenciou a esterilidade dos materiais após a irradiação, comprovando sua adequação para aplicação clínica. A quantificação de DNA revelou a efetividade da descelularização, reduzindo significativamente o conteúdo de DNA original do tecido. CONCLUSÕES: Foi possível o desenvolvimento de uma matriz oriunda da pele de tilápia, sendo ela não citotóxica, estéril, portadora de morfologia adequada para aplicação clínica e acelular. Assim, contribuindo para inovação da ciência brasileira.

OBJECTIVE: To produce a biocompatible, non-toxic, and sterile scaffold based on extracellular matrix (ECM) for the treatment of burns and wounds. The utilization of tilapia skin was explored as an alternative, highlighting its similar properties to human skin and its successful application in different medical areas. METHODS: The process of preparing tilapia skin-derived ECM scaffolds is described, including steps of degreasing, decontamination, decellularization, and gamma ray irradiation at 25kGy for sterilization. Laboratory tests were conducted to assess in vitro cellular toxicity using the MTT method, histological analyses with hematoxylin-eosin staining, microbiological analyses, and DNA quantification. RESULTS: It is emphasized that the produced ECM scaffolds were effectively decellularized, preserving the extracellular matrix and demonstrating non-cytotoxicity. Furthermore, microbiological analysis evidenced the sterility of the materials after irradiation, confirming their suitability for clinical application. DNA quantification revealed the effectiveness of decellularization, significantly reducing the original DNA content of the tissue. CONCLUSIONS: The development of a tilapia skin-derived matrix was achieved, which is non-cytotoxic, sterile, possesses suitable morphology for clinical application, and is acellular. Thus, contributing to the innovation of Brazilian science.

Funcionalização de matriz colágena estável em volume utilizando Fibrina Rica em Plaquetas injetável (i-PRF) para o tratamento de Recessão Gengival unitária / Volume-stable collagen matrix (VCMX) biofunctionalized wit injectable platelet-rich fibrin (i-PRF) for the treatment of single gingival recession: randomized clinical trial

Substitutos de enxerto de tecido conjuntivo têm sido amplamente utilizados para superar as limitações dos enxertos autógenos no tratamento de defeitos dos tecidos moles periodontais e peri-implantares. No entanto, o desempenho clínico desses biomateriais ainda é inferior. A biofuncionalização de matrizes colágenas usando fibrina rica em plaquetas injetável (i-PRF) foi proposta como uma estratégia para aprimorar a bioatividade e, portanto, a eficácia clínica desses substitutos mucosos. Desta forma, o objetivo deste estudo foi avaliar a eficácia do uso da matriz colágena estável em volume (FG) biofuncionalizada com i-PRF no tratamento de recessões gengivais unitárias (RGs) do ponto de vista clínico, estético e de parâmetros centrados no paciente. Para tal, foram selecionados 66 pacientes portadores de RGs unitárias RT1, os quais foram alocados aleatoriamente em um dos seguintes grupos: grupo CAF (n=22), retalho posicionado coronariamente (CAF); grupo CAF+FG (n=22), CAF associado à FG; e grupo CAF+FG+i-PRF (n=22), CAF associado à FG biofuncionalizada com i-PRF. Após 6 meses, os três grupos apresentaram taxas de recobrimento radicular significativas [CAF: 69,1% (2,02 ± 1,06 mm); CAF+FG: 67,44% (1,7 ± 0,81 mm) e CAF+FG+i-PRF: 64,92% (1,64 ± 0,80 mm), sem diferença entre os grupos (p=0,33). Os grupos que receberam os biomateriais forneceram um maior ganho em espessura de tecido queratinizado (ETQ) (CAF: 0,12 ± 0,2 mm; CAF+FG: 0,43 ± 0,24 mm; CAF+FG+i-PRF: 0,48 ± 0,25 mm; p=0,000). Não foram observadas diferenças significativas em termos de altura de tecido queratinizado em nenhum dos grupos e tempos avaliados (p>0,05). Todos os grupos apresentaram redução significativa da hipersensibilidade dentinária e melhorias nas condições estéticas (p>0,05). Também não foram observadas diferenças em termos de dor e morbidade pósoperatórias (p>0,05). Dentro das limitações do presente estudo, conclui-se que as três abordagens forneceram resultados semelhantes e satisfatórios após 6 meses de acompanhamento. A adição da FG, biofuncionalizada ou não com i-PRF, proporcionou benefícios adicionais em termos de ganho de ETQ. (AU)

Soft tissue graft substitutes have been widely used to overcome the limitations of autogenous grafts in the treatment of periodontal and peri-implant soft tissue defects. However, the clinical performance of these biomaterials is still inferior. The biofunctionalization of collagen matrices using injectable platelet-rich fibrin (i-PRF) has been proposed as a strategy to enhance the bioactivity and, therefore, the clinical efficacy of these biomaterials. Thus, the aim of this study was to evaluate the effectiveness of using biofunctionalized volume-stable collagen matrix (VCMX) with i-PRF in the treatment of single gingival recessions (GRs) from clinical, esthetic, and patient-centered parameters. For this purpose, 66 patients with single RT GRs were selected and randomly allocated to one of the following groups: CAF group (n=22), coronally advanced flap (CAF); CAF+VCMX group (n=22), CAF combined with VCMX; and CAF+ VCMX +iPRF group (n=22), CAF combined with biofunctionalized VCMX with i-PRF. After 6 months, all three groups exhibited significant root coverage rates [CAF: 69.1% (2.02 ± 1.06 mm); CAF+FG: 67.44% (1.7 ± 0.81 mm); and CAF+FG+iPRF: 64.92% (1.64 ± 0.80 mm), with no difference between the groups (p=0.33). The groups that received the biomaterials showed a greater gain in keratinized tissue thickness (KTT) (CAF: 0.12 ± 0.2 mm; CAF+FG: 0.43 ± 0.24 mm; CAF+FG+i-PRF: 0.48 ± 0.25 mm; p=0.000). No significant differences were observed in terms of keratinized tissue height in any of the groups and assessed time points (p>0.05). All groups showed a significant reduction in dentin hypersensitivity and improvements in esthetic conditions (p>0.05). No differences were also observed in terms of post-operative pain and morbidity (p>0.05). Within the limitations of this study, it is concluded that all three approaches provided similar and satisfactory results after 6 months of follow-up. The addition of VCMX, whether biofunctionalized or not with i-PRF, provided additional benefits in terms of keratinized tissue thickness gain. (AU)

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.

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.

Application of three dimensional bio-printing materials for tissue engineering tracheal grafting / 中华器官移植杂志

Currently three dimensional bio-printing technology has become one of the hot topics for tissue engineering tracheal grafting.Different biomaterials have their own performance advantages in the preparation and regeneration of tracheal scaffolds.It is particularly imperative to seek natural or polymeric materials with excellent profiles of printability, structural stability and biocompatibility to enable neo-cartilage formation, neo-epithelialization and neo-vascularization of tissue engineering trachea grafting.This review summarized the shortcomings and challenges of classifying and applying materials for three dimensional bio-printing tissue engineering trachea, aiming to provide new rationales for researches and applications of tissue engineering tracheal grafting.

The study of the whole bladder acellular matrix prepared by the perfusion decellularization system combined with the adipose-derived stem cells to construct the tissue engineering bladder / 中华泌尿外科杂志

Objective:To prepare the whole bladder acellular matrix (BAM) using the self-designed perfusion decellularization system, and evaluate the feasibility of constructing the tissue engineering bladder with the adipose-derived stem cells (ADSCs).Methods:This study was conducted from October 2020 to April 2021. The self-designed perfusion decellularization system was used, and four different decellularization protocols (group A, group B, group C and group D) were formulated, according to the flow direction of the perfusate and the action time of different decellularization solutions. Among them, the urethral orifice of the bladder tissue was used as the outflow tract of the perfusion fluid in groups A and B. The top of the bladder was cut off and used as the outflow tract of the perfusion fluid in groups C and D. In groups A and C, 1% Triton X-100 was treated for 6 h, and 1% sodium dodecyl sulfate (SDS) was treated for 2 h. In groups B and D, 1% Triton X-100 was treated for 7 h, and 1% sodium dodecyl sulfate (SDS) was treated for 1 h. In addition, the tissue in the normal bladder group was directly obtained from the natural bladder tissue, which did not require perfusion, cryopreservation and thawing. The fast and efficient decellularization protocol was screened out through HE, DAPI, Masson trichrome and Alcian Blue staining and quantitative analyses to prepare the whole bladder scaffold. The prepared BAM was used as the scaffold material, and the ADSCs were used as the seeding cells to construct the tissue engineering bladder. HE and DAPI staining were used to observe the distribution of ADSCs on the BAM.Results:HE and DAPI staining showed that there was no obvious nuclear residue in the group C. Masson trichrome and Alcian Blue staining showed that the collagen structure and glycosaminoglycan were well preserved in the group C. There was no significant difference in bladder wall thickness between the group C and the normal bladder group [(975.44±158.62)μm vs.(1 064.49±168.52)μm, P > 0.05]. The DNA content in the group C [(43.59 ±4.59) ng/mg] was lower than that in the normal bladder group, group A, group B and group D [(532.50±26.69), (135.17±6.99), (182.49±13.69) and(84.00±4.38)ng/mg], and the difference was statistically significant ( P<0.05). The collagen content [(10.98 ± 0.29)μg/mg] and glycosaminoglycan content [(2.30±0.18)μg/mg] in group C were not significantly different with those in the normal bladder group [(11.69±0.49) and (2.36±0.09)μg/mg, P>0.05]. Scanning electron microscopy showed that a large number of pore structures could be observed on the surface of the prepared BAM in groups A-D and were facilitated to cell adhesion. The isolated and cultured ADSCs were identified by flow cytometry to confirm the positive expression of CD90 and CD29, and the negative expression of CD45 and CD106. Live/dead staining and CCK-8 detection confirmed that the prepared BAM in the group C had no cytotoxicity. HE and DAPI staining showed that a large number of ADSCs were distributed on the surface and inside of the tissue engineering bladder. Conclusions:The whole bladder shape BAM prepared by the self-designed perfusion decellularization system could be used as the scaffold material for bladder tissue engineering, and the constructed tissue engineering bladder could be used for bladder repair and reconstruction.

Recent advances of acellular cartilage matrix in cartilage regeneration / 中华骨科杂志

Osteoarthritis is a common degenerative joint disease, and cartilage damage is often considered an early factor in irreversible joint degeneration. Repairing damaged cartilage remains a medical challenge due to its limited ability to self-repair and regenerate. In recent years, the application of tissue engineering strategies to treat cartilage defects has been recognized as an emerging therapeutic avenue. Acellular cartilage matrix (ACM) is an ideal material for cartilage repair and regeneration as it retains the extracellular matrix structure and bioactive components of natural cartilage, mimicking the extracellular environment of natural cartilage to the greatest extent. Type II collagen is the main type of hyaline cartilage and plays an important role in regulating the mechanical properties of cartilage tissue. It has been shown that type II collagen, growth factors and the hypoxic microenvironment play important roles in promoting cartilage regeneration. Type II collagen induces cell aggregation and chondrogenic differentiation in a specific way; Various growth factors contained in the ACM induce Sox9 expression and promote chondrogenic differentiation of stem cells; The hypoxic microenvironment upregulates the expression of type II collagen (COL2A1), Sox9 and maintains chondrocyte phenotype. In addition, ACM has been widely used in cartilage regeneration studies, either as a decellularized scaffold, hydrogel or 3D bioprinting technique for the repair of defective cartilage. Although the ACM-derived biomaterials discussed in this paper have many advantages, there are still some difficulties in their practical applications, such as loss of ACM components and reduced scaffold performance, which are still worth exploring in depth.

Research progress in the role of mesenchymal stem cell sheets and their derivatives in bone defect repair / 中华创伤杂志

Bone defects are mostly caused by severe trauma, infection, tumor resection and congenital malformations, which adversely affect their health and quality of life. So far, the bone defects are mainly filled with autologous or allogeneic bone grafting, which has problems such as donor shortage, secondary bone injury and scarring. In recent years, the rise of bone tissue engineering has provided a new way for repair of bone defects, in which mesenchymal stem cell (MSC) sheets prepared by using the principle of tissue engineering can well solve the above problems of autologous or allogeneic bone grafting. With the development of preparation technology, new bone defect repair materials such as decellularized extracellular matrix (ECM) sheets and MSC/ECM clumps have been derived on the basis of MSC sheets. Therefore, the authors reviewed the preparation and the role of MSC sheets and their derivatives in bone defect repair, hoping to provide a reference for basic research and clinical treatment related to bone defect repair.