Influence of the addition of nanohydroxyapatite to scaffolds on proliferation and differentiation of human mesenchymal stem cells: a systematic review of in vitro studies

One of the main challenges of tissue engineering in dentistry is to replace bone and dental tissues with strategies or techniques that simulate physiological tissue repair conditions. This systematic review of in vitro studies aimed to evaluate the influence of the addition of nanohydroxyapatite (NHap) to scaffolds on cell proliferation and osteogenic and odontogenic differentiation of human mesenchymal stem cells. In vitro studies on human stem cells that proliferated and differentiated into odontogenic and osteogenic cells in scaffolds containing NHap were included in this study. Searches in PubMed/MEDLINE, Scopus, Web of Science, OpenGrey, ProQuest, and Cochrane Library electronic databases were performed. The total of 333 articles was found across all databases. After reading and analyzing titles and abstracts, 8 articles were selected for full reading and extraction of qualitative data. Results showed that despite the large variability in scaffold composition, NHap-containing scaffolds promoted high rates of cell proliferation, increased alkaline phosphatase (ALP) activity during short culture periods, and induced differentiation, as evidenced by the high expression of genes involved in osteogenesis and odontogenesis. However, further studies with greater standardization regarding NHap concentration, type of scaffolds, and evaluation period are needed to observe possible interference of these criteria in the action of NHap on the proliferation and differentiation of human stem cells.

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)

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.

Automated Assessment of Cell Infiltration and Removal in Decellularized Scaffolds - Experimental Study in Rabbits / Avaliação automatizada da infiltração e remoção celular em scaffolds descelularizados - Estudo experimental em coelhos

Abstract Objective Semiquantitative and automated measurement of nuclear material removal and cell infiltration in decellularized tendon scaffolds (DTSs). Method 16 pure New Zealand rabbits were used, and the gastrocnemius muscle tendon was collected bilaterally from half of these animals (16 tendons collected); 4 were kept as control and 12 were submitted to the decellularization protocol (DTS). Eight of the DTSs were used as an in vivo implant in the experimental rotator cuff tear (RCT) model, and the rest, as well as the controls, were used in the semiquantitative and automated evaluation of nuclear material removal. The eight additional rabbits were used to make the experimental model of RCT and subsequent evaluation of cellular infiltration after 2 or 8 weeks, within the DTS. Results The semiquantitative and automated analysis used demonstrated a removal of 79% of nuclear material (p< 0.001 and power > 99%) and a decrease of 88% (p < 0.001 and power >99%) in the area occupied by nuclear material after the decellularization protocol. On cell infiltration in DTS, an increase of 256% (p < 0.001 and power >99%) in the number of cells within the DTS was observed in the comparison between 2 and 8 weeks postoperatively. Conclusion The proposed semiquantitative and automated measurement method was able to objectively measure the removal of nuclear material and cell infiltration in DTS.

Resumo Objetivo Mensuração semiquantitativa e automatizada da remoção de material nuclear e da infiltração celular em scaffolds tendinosos descelularizados (STDs). Método Foram utilizados 16 coelhos Nova Zelândia puros, sendo o tendão do músculo gastrocnêmio coletado bilateralmente de metade destes animais (16 tendões coletados); 4 foram mantidos como controle e 12 foram submetidos ao protocolo de descelularização (STD). Dos STDs, 8 foram utilizados como implante in vivo no modelo experimental de lesão do manguito rotador (LMR) e os restantes, assim como os controles, foram utilizados na avaliação semiquantitativa e automatizada da remoção de material nuclear. Os oito coelhos adicionais foram utilizados na confecção do modelo experimental de LMR e posterior avaliação da infiltração celular após 2 ou 8 semanas, dentro do STD. Resultados A análise semiquantitativa e automatizada utilizada demonstrou uma remoção de 79% do material nuclear (p< 0,001 e poder > 99%) e uma diminuição de 88% (p< 0,001 e poder > 99%) na área ocupada por material nuclear após o protocolo de descelularização. Sobre a infiltração celular no STD, foi observado um aumento de 256% (p< 0,001 e poder > 99%) no número de células dentro do STD na comparação entre 2 e 8 semanas de pós-operatório. Conclusão O método de mensuração semiquantitativo e automatizado proposto foi capaz de mensurar objetivamente a remoção de material nuclear e a infiltração celular no STD.

The effect of scaffold hydroxyapatite derived from portunus pelagicus shell on the expression of fibroblast growth factor-2 (fgf-2) and bone morphogenetic proteins-2 (bmp -2) in the extraction sockets of cavia cobaya / El efecto del scaffold de hidroxiapatita derivada de portunus pelagicus sobre la expresión del factor de crecimiento de fibroblastos-2 (FGF-2) y las proteínas morfogenéticas óseas-2 (BMP-2) en los alvéolos dentarios de cavia cobaya

Objetive: To determine the expression of Fibroblast Growth Factor (FGF)-2 and Bone Morphogenetic Protein (BMP)-2 after application of scaffold hydroxyapatite from Rajungan crab shell (Portunus pelagicus) in the tooth extraction socket of Cavia cobaya. Material and Methods: This study used a post-test only control group design with 28 Cavia cobaya separated into two groups, control and treatment group. The left mandibular incisor was extracted, and socket preservation was conducted. A hydroxyapatite graft derived from crab shells was mixed with gelatin and eventually turned into a scaffold, which was afterward put into the extraction socket. After 7 days and 14 days, each group was terminated and examined using immunohistochemical staining to observe the expression of FGF-2 and BMP-2. One-Way Anova and Tukey HSD were used to examine the research data. Results: FGF-2 and BMP-2 expressions were observed higher in the group that received hydroxyapatite scaffold at the post-extraction socket than those in the group that did not receive hydroxyapatite scaffold. Conclusion: The application of a hydroxyapatite scaffold from Rajungan crab shell (Portunus pelagicus) to the tooth extraction socket can increase FGF-2 and BMP-2 expression.

Objetivo: Determinar la expresión del factor de crecimiento de fibroblastos (FGF)-2 y la proteína morfogenética ósea (BMP)-2 después de la aplicación de hidroxiapatita de andamio de caparazón de cangrejo Rajungan (Portunus pelagicus) en el alvéolo de extracción dental de Cavia cobaya. Material y Métodos: Este estudio utilizó un diseño de grupo de control solo posterior a la prueba con 28 Cavia cobaya separados en dos grupos, grupo de control y grupo de tratamiento. Se extrajo el incisivo mandibular izquierdo y se realizó la preservación del alvéolo. Un injerto de hidroxiapatita derivado de caparazones de cangrejo se mezcló con gelatina y se convirtió en un andamio, que luego se colocó en el alvéolo de extracción. Después de 7 días y 14 días, se terminó cada grupo y se examinó mediante tinción inmunohistoquímica para observar la expresión de FGF-2 y BMP-2. Se utilizaron One-Way Anova y Tukey HSD para examinar los datos de la investigación. Resultados: Las expresiones de FGF-2 y BMP-2 se observaron más altas en el grupo que recibió la estructura de hidroxiapatita en el alvéolo posterior a la extracción que en el grupo que no recibió la estructura de hidroxiapatita. Conclusión: La aplicación de un andamio de hidroxiapatita de caparazón de cangrejo Rajungan (Portunus pelagicus) al alvéolo de extracción dental puede aumentar la expresión de FGF-2 y BMP-2.

New strategies for cartilage regeneration in tissue-engineered trachea / 国际外科学杂志

The normal ventilatory function is severely impaired by tracheal traumas, stenoses, tumors and some congenital diseases, which could result in tissue hypoxia and endangering the life of the patient. Resection and reconstruction of tracheal lesions is the most effective way to treat these diseases. At present, there is still no long-term safe and reliable method to achieve the reconstruction of long-segment trachea injury in clinical practice, and tissue-engineered trachea may be the solution to this situation. Cartilage, as one of the most important parts of tissue engineered trachea, plays a key role in providing mechanical support and maintaining the integrity of trachea. Tracheal tissue engineering cartilage regeneration process consists of several important parts, including the source of the cartilage cells, tissue engineering scaffold construction strategy and hydrogel composite scaffold material preparation, and the affecting factors of biological activity and application. This article reviews the new strategies of tissue engineered tracheal cartilage regeneration and the existing obstacles in order to provide reference for clinical practice.

Three-dimensional printed poly (L-lactide) and hydroxyapatite composite for reconstruction of critical bone defect in rabbits

ABSTRACT Purpose To use a 3D printed poly (L-lactide) acid (PLLA) and hydroxyapatite (HA) composite as a bone substitute for reconstruction of a critical bone defect in the radius of rabbits. Methods A 1.5 cm ostectomy was performed in the radial diaphysis of 60 New Zealand white rabbits. The rabbits were divided into three groups according to surgical treatment of the bone defect (group I - control, group II - bone graft, group III - 3D PLLA). Each group was divided into four subgroups with different radiographic and histopathologic evaluation times (T1 - 15 days, T2 - 30 days, T3 - 60 days, T4 - 90 days). Results The implant group had greater clinically lameness (p = 0.02), edema (p = 0.007), pain (p = 0.04) and more complications at the surgical site (p = 0.03). Histologically, this group showed greater congestion (p = 0.04), hemorrhage (p = 0.04) and inflammation. Osteogenesis was microscopically similar between days (p = 0.54) and treatments (p = 0.17), even though radiographically, more effective bone healing occurred in the graft group (II), with more callus and bone bridge formation. Conclusions The customization of a 3D PLLA/HA scaffold was successful. However, in animals receiving the polymer-ceramic composite less bone callus and bone bridge was formed compared to the graft group.

Biomaterials for bone regeneration: an orthopedic and dentistry overview

Because bone-associated diseases are increasing, a variety of tissue engineering approaches with bone regeneration purposes have been proposed over the last years. Bone tissue provides a number of important physiological and structural functions in the human body, being essential for hematopoietic maintenance and for providing support and protection of vital organs. Therefore, efforts to develop the ideal scaffold which is able to guide the bone regeneration processes is a relevant target for tissue engineering researchers. Several techniques have been used for scaffolding approaches, such as diverse types of biomaterials. On the other hand, metallic biomaterials are widely used as support devices in dentistry and orthopedics, constituting an important complement for the scaffolds. Hence, the aim of this review is to provide an overview of the degradable biomaterials and metal biomaterials proposed for bone regeneration in the orthopedic and dentistry fields in the last years.

Aplicaciones de la impresión 3D en cirugía plástica reconstructiva / Use of 3D printing in reconstructive plastic surgery

Resumen La impresión 3D es una tecnología interesante en constante evolución. También conocida como manufactura aditiva, consiste en la conversión de diseños digitales a modelos físicos mediante la adición de capas sucesivas de material. En años recientes, y tras el vencimiento de múltiples patentes, diversos campos de las ciencias de la salud se han interesado en sus posibles usos, siendo la cirugía plástica una de las especialidades médicas que más ha aprovechado sus ventajas y aplicaciones, en especial la capacidad de crear dispositivos altamente personalizados a costos accesibles. Teniendo en cuenta lo anterior, el objetivo del presente artículo es describir los usos de la impresión 3D en cirugía plástica reconstructiva a partir de una revisión de la literatura. Las principales aplicaciones de la impresión 3D descritas en la literatura incluyen su capacidad para crear modelos anatómicos basados en estudios de imagen de pacientes, que a su vez permiten planificar procedimientos quirúrgicos, fabricar implantes y prótesis personalizadas, crear instrumental quirúrgico para usos específicos y usar biotintas en ingeniería tisular. La impresión 3D es una tecnología prometedora con el potencial de implementar cambios positivos en la práctica de la cirugía plástica reconstructiva en el corto y mediano plazo.

Abstract 3D printing is an interesting technology in constant evolution. Also known as additive manufacturing, it consists of the conversion of digital designs into physical models by successively adding material layer by layer. In recent years, and after the expiration of multiple patents, several fields of health sciences have approached this type of technology, plastic surgery being one of the medical specialties that has taken advantage of its benefits and applications, especially the ability to create highly customized devices at low costs. With this in mind, the objective of this work is to describe the uses of 3D printing in reconstructive plastic surgery based on a literature review. The main applications of 3D printing described in the literature include its ability to create anatomical models based on patient imaging studies, which in turn allow planning surgical procedures, manufacturing custom implants and prostheses, creating surgical or instrumental simulators, and using bioinks in tissue engineering. 3D printing is a promising technology with the potential to cause positive changes in the field of reconstructive plastic surgery in the short and medium term.

Emphasis on biomaterial research in bone defect repair of osteoporotic fracture / 中华创伤杂志

Osteoporosis results in decreased bone mass,impaired bone strength and bone microstructure,and thus can easily cause bone fracture.Osteoporosis is one of the common diseases troubling the aging people.Due to the decreased activity of osteoblasts as well as impaired osteogenic differentiation of mesenchymal stem cells,the repair of bone defects accompanied with osteoporosis is very limited.It is a promising way to enhance the healing effect of such bone defect through implanting biomaterials with improved physical and chemical properties as well as elevated bioactivities,since it can mediate the activities of osteogenesis related cells in situ.The author summarizes the popular methods for the modification of biomaterials used for repairing bone defect caused by osteoporotic fractures and provides a prospect in this field,with the aim to provide a reference for the treatment of osteoporotic fractures.

Emphasis on biomaterial research in bone defect repair of osteoporotic fracture / 中华创伤杂志

Osteoporosis results in decreased bone mass, impaired bone strength and bone microstructure, and thus can easily cause bone fracture. Osteoporosis is one of the common diseases troubling the aging people. Due to the decreased activity of osteoblasts as well as impaired osteogenic differentiation of mesenchymal stem cells, the repair of bone defects accompanied with osteoporosis is very limited. It is a promising way to enhance the healing effect of such bone defect through implanting biomaterials with improved physical and chemical properties as well as elevated bioactivities, since it can mediate the activities of osteogenesis related cells in situ. The author summarizes the popular methods for the modification of biomaterials used for repairing bone defect caused by osteoporotic fractures and provides a prospect in this field, with the aim to provide a reference for the treatment of osteoporotic fractures.

Repair of rabbit articular cartilage defect by a novel injectable bioactive glass scaffold / 中华骨科杂志

Objective@#By comparing different repairing effects of different methods on articular cartilage defects in rabbit model, the ability of a new bioactive glass scaffold to repair cartilage defect was studied.@*Methods@#We prepared the PSC/CS bone cement by mixing the bioactive glass (BG) powder composed of 10.8%P2O5-54.2%SiO2-35%CaO (PSC), chitosan solution (CS) and calcium sulfate hemihydrate (CSH), then the bone cement was sized by a mold to form cylindrical scaffold. In vivo experiment, 18 male rabbits were divided into three groups randomly, including blank group, BG group and TGF-β1 group, which was added TGF-β1 into BG scaffold. Both knees of each rabbit were made cartilage defect for the same group, and no intervention was applied in B group, then implanted scaffolds into defects in both experimental groups. At 6 and 12 weeks after surgery, observed the macroscopic growth, histologic staining and collagen II immunohistochemistry (IHC), and the International Cartilage Repair Society (ICRS) and Wakitani score were used to analyze the experimental results quantitatively.@*Results@#At 6 weeks after surgery, there was no obvious difference between blank group and BG groups, but the macroscopic result of TGF-β1 group was better than the other two groups and its ICRS score 4.67±0.52 points was statistically higher than BG group 2.83±0.75 points (t=-2.817, P=0.015). As to the comparison of histologic staining and Wakitani socre among three groups, no statistical difference was observed (blank group=13.67±0.52, BG group=13.83±0.41, TGF-β1 group=13.33±1.03). At 12 weeks after surgery, there was still no obvious difference between blank and BG groups, while the results of macroscopic observation and ICRS score in TGF-β1 group were significantly higher than them 9.01±0.63 points (blank group vs TGF-β1 group: t=-2.289, P=0.022; BG group vs TGF-β1 group: t=-2.326, P=0.020). More importantly, much deeper positive staining were observed in TGF-β1 group, and the Wakitani score was higher than the other two groups (blank group=9.83±1.33, BG group=9.51±1.05, TGF-β1 group=6.50±1.38, blank group vs TGF-β1 group: t=-2.771, P=0.007; BG group vs TGF-β1 group: t=-2.756, P=0.006). By comparing the degree of histologic staining and Col II expression with normal cartilage, the regenerated tissue in TGF-β1 group was similar.@*Conclusion@#Single PSC/CS scaffold doesn’t possess excellent ability to repair cartilage defect. When TGF-β1 was added into PSC/CS bioactive glass, the scaffold was able to promote cartilage defect repair, and the regenerated tissue was similar to normal cartilage.

Repair of rabbit articular cartilage defect by a novel injectable bioactive glass scaffold / 中华骨科杂志

Objective By comparing different repairing effects of different methods on articular cartilage defects in rabbit model,the ability of a new bioactive glass scaffold to repair cartilage defect was studied.Methods We prepared the PSC/CS bone cement by mixing the bioactive glass (BG) powder composed of 10.8％P205-54.2％SiO2-35％CaO (PSC),chitosan solution (CS) and calcium sulfate hemihydrate (CSH),then the bone cement was sized by a mold to form cylindrical scaffold.In vivo experiment,18 male rabbits were divided into three groups randomly,including blank group,BG group and TGF-β1 group,which was added TGF-β1 into BG scaffold.Both knees of each rabbit were made cartilage defect for the same group,and no intervention was applied in B group,then implanted scaffolds into defects in both experimental groups.At 6 and 12 weeks after surgery,observed the macroscopic growth,histologic staining and collagen Ⅱ immunohistochemistry (IHC),and the International Cartilage Repair Society (ICRS) and Wakitani score were used to analyze the experimental results quantitatively.Results At 6 weeks after surgery,there was no obvious difference between blank group and BG groups,but the macroscopic result of TGF-β1 group was better than the other two groups and its ICRS score 4.67±0.52 points was statistically higher than BG group 2.83±0.75 points (t=-2.817,P=0.015).As to the comparison of histologic staining and Wakitani socre among three groups,no statistical difference was observed (blank group=13.67±0.52,BG group=13.83±0.41,TGF-β1 group=13.33±1.03).At 12 weeks after surgery,there was still no obvious difference between blank and BG groups,while the results of macroscopic observation and ICRS score in TGF-β1 group were significantly higher than them 9.01±0.63 points (blank group vs TGF-β1 group:t=-2.289,P=0.022;BG group vs TGF-β1 group:t=-2.326,P=0.020).More importantly,much deeper positive staining were observed in TGF-β1 group,and the Wakitani score was higher than the other two groups (blank group=9.83 ± 1.33,BG group=9.51 ± 1.05,TGF-β1 group=6.50± 1.38,blank group vs TGF-β 1 group:t=-2.771,P=0.007;BG group vs TGF-β1 group:t=-2.756,P=0.006).By comparing the degree of histologic staining and Col Ⅱ expression with normal cartilage,the regenerated tissue in TGF-β1 group was similar.Conclusion Single PSC/CS scaffold doesn't possess excellent ability to repair cartilage defect.When TGF-β1 was added into PSC/CS bioactive glass,the scaffold was able to promote cartilage defect repair,and the regenerated tissue was similar to normal cartilage.

Assessment of stem cell viability in the initial healing period in rabbits with a cranial bone defect according to the type and form of scaffold

PURPOSE: Increased bone regeneration has been achieved through the use of stem cells in combination with graft material. However, the survival of transplanted stem cells remains a major concern. The purpose of this study was to evaluate the viability of transplanted mesenchymal stem cells (MSCs) at an early time point (24 hours) based on the type and form of the scaffold used, including type I collagen membrane and synthetic bone. METHODS: The stem cells were obtained from the periosteum of the otherwise healthy dental patients. Four symmetrical circular defects measuring 6 mm in diameter were made in New Zealand white rabbits using a trephine drill. The defects were grafted with 1) synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×105 MSCs, 2) collagen membrane and 1×105 MSCs, 3) β-TCP/HA+collagen membrane and 1×105 MSCs, or 4) β-TCP/HA, a chipped collagen membrane and 1×105 MSCs. Cellular viability and the cell migration rate were analyzed. RESULTS: Cells were easily separated from the collagen membrane, but not from synthetic bone. The number of stem cells attached to synthetic bone in groups 1, 3, and 4 seemed to be similar. Cellular viability in group 2 was significantly higher than in the other groups (P0.05). CONCLUSIONS: This study showed that stem cells can be applied when a membrane is used as a scaffold under no or minimal pressure. When space maintenance is needed, stem cells can be loaded onto synthetic bone with a chipped membrane to enhance the survival rate.

State-of-the-Art Strategies for the Vascularization of Three-Dimensional Engineered Organs

Engineering three-dimensional (3D) implantable tissue constructs is a promising strategy for replacing damaged or diseased tissues and organs with functional replacements. However, the efficient vascularization of new 3D organs is a major scientific and technical challenge since large tissue constructs or organs require a constant blood supply to survive in vivo. Current approaches to solving this problem generally fall into the following three major categories: (a) cell-based, (b) angiogenic factor-based, and (c) scaffold-based. In this review, we summarize state-of-the-art technologies that are used to develop complex, stable, and functional vasculature for engineered 3D tissue constructs and organs; additionally, we have suggested directions for future research.

Analysis of pulp revascularization of immature permanent teeth with PRP / 中国基层医药

Objective To discuss the clinical effect of different scaffold in pulp vascular regeneration . Methods 22 young permanent teeth with periapical lesions were randomly divided into observation group and control group,11cases in each group .After the disinfection protocol was completed , the apexes of the control group were irritated to initiate bleeding to produce a blood clot to achieve pulp revascularization ,while the observation group used platelet rich plasma as physical scaffold to operate pulp revasculrization .Results In the control group , the two patients showed painful tooth at 1 and 8 months,the three patients showed healed periapical lesions and narrowed apical foramen at 12 and 18 months ,the six patients showed healed periapical lesions and closure of the apical fora -men at 12 and 18 months.In the observation group ,the three patients showed painful tooth at 1,3 and 8 months,the four patients showed healed periapical lesions and narrowed apical foramen at 12 and 18 months,the four patients showed healed periapical lesions and closure of the apical foramen at 12 and 18 months.There was no statistically significant difference between the observation group and control group by Fisher's exact probabilities (P=1.000). Conclusion Platelet rich plasma is potentially an ideal scaffold for pulp revascularization .

Influence of dynamic mechanical stimulation on tissue engineering annulus fibrosus / 中华骨科杂志

Objective To investigate the influence of dynamic mechanical stimulation on the annulus fibrosus (AF) cells seeded on silk scaffolds.Methods AF cells were isolated from rabbits and were seeded on the scaffold,then cultured for 3,7,14 days with different range of dynamic compression.Stereomicroscope and scanning electron microscope (SEM) was used to observe the surface morphology of tissue engineering annulus fibrosus cells (TE-AFs).After fixation,samples were harvested for histological staining.AF cells related extracellular matrix (ECM) was evaluated by the quantitative analysis of total DNA,proteoglycan and collagen I.The mechanical properties were compared within different groups.Results Stereomicroscope and SEM results showed that the colors of TE-AFs in all groups were deepening with time going.SEM showed cell adhesion on the scaffold and the secretion of extracellular matrix.Histological,immunohistochemical staining,biochemical quantitative analysis and total DNA content showed that the AF cells inside scaffolds could support AF cell attachment,proliferation and secretion.As a result,the compressive properties were enhanced with increasing culture time.Stereomicroscope showed that the colors of TE-AFs in all groups were deepening with time going after dynamic compression.HE staining,Safranin O staining and Type Ⅰ collagen staining showed that cell proliferation and secretion,GAG secretion and collagen secretion were increased with time going within different groups.Quantitation of GAG achieved maximum in 15％ strain group,and quantitation of collagen achieved maximum in 10％ strain group.The total DNA content achieved maximum in 5％ strain group,and compression elastic modulus achieved maximum in 15％strain goup.The height of TE-AFs did not change after mechanical stimulation for 14 days.Conclusion Suitable mechanical stimulation is a positive factor for new AF tissue engineering that will tend to the nature tissue.Excessive compression can accelerate the progress of cell apoptosis.

Osteochondral tissue engineering based on biomimetic osteochondral scaffold contained calcified cartilage layer compounding with ADSCs in vivo / 中华骨科杂志

Objective The biomimetic osteochondral scaffold contained calcified cartilage layer(CCL) was fabricated using slik fibroin (SF) and hydroxyapatite (HA) for materials.To investigate effects of biomimetic osteochondral scaffold contained CCL compounding with ADSCs on regeneration of the osteochondral defect on the rabbit knee,explore the feasibility of this design as a concept of osteochondral tissue engineering.Methods We fabricated a novel biomimetic osteochondral scaffold with CCL using SF and HA by the combination of paraffin-sphere leaching and modified temperature gradient-guided thermal-induced phase separation (TIPS) technique.The pore size,porosity,and compressive modulus of elasticity of the scaffold cartilage layer and the osteogenic layer were measured by scanning electron microscopy and microscopy CT.The osteochondral defect model on rabbit bilateral knees were established,and implanted with the non-CCL group (non-CCL scaffold compounding with ADSCs) and CCL group (CCL scaffold compounding with ADSCs).At 4,8 and 12 weeks after implantation,the rabbits were euthanized,respectively.Gross observation score,histological and immunohistochemical assessment,biochemical quantitative of new osteochondral tissue,micro-CT scans for new bone,were executed.We evaluated the regeneration of osteochondral defects in each group,and verified the role of CCL in vivo.Results The biomimetic osteochondral scaffold with CCL had a consecutively overlapping trilayer structure with different densities and pore structures,including a chondral layer (top layer),intermediate layer and bony layer (bottom layer).The cartilage layer had a well-oriented microporous structure with a uniform distribution with a pore size of (112.43± 12.65)μm and a porosity of 90.25％±2.05％.The subchondral bone layer had a good three-dimensional macroporous structure,good connectivity,pore size (362.23±26.52) μm,porosity of osteogenic layer was 85.30％± 1.80％.The cartilage regeneration in CCL+AD-SCs group was better than non-CCL+ADSCs group.The content of GAG and type Ⅱ collagen in new cartilage tissue in CCL+AD-SCs group was much more than non-CCL+ADSCs group.The new bone tissue analysis and biomechanical testing had no significant differences between the two groups.Conclusion The biomimetic osteochondral SF/HA scaffold contained CCL mimics the structure of normal osteochondral tissue with good 3-dimensional pore structure and biocompatibility.The scaffold complex autologous ADSCs successfully repair osteochondral defects in rabbit knee,and the presence of CCL accelerates the growth of cartilage.