Small intestinal submucosa (SIS) is a natural decellularized extracellular matrix material. Due to its excellent biocompatibility, unique biomechanical properties and biological activity, it has been widely used as a scaffold in regenerative medicine. This article reviews the recent progress in the characterization and medical application of SIS respectively. The specific biological properties of the SIS, as well as its interaction with cells, are highlighted. Some of the SIS products and clinical cases are also reviewed and discussed.
Objective
To investigate the expression of neutrophil gelatinase-associated lipocalin (NGAL) signaling pathways in the early stage of porcine vein graft restenosis, and to explore the possible role and mechanism in the early vein graftrestenosis after coronary artery bypass surgery.
Methods
We selected 18 ordinary healthy pigs weighing 25-30 kg and collected samples of the vein graft of pigs at the preoperation and postoperative days 7, 14 and 30. Hematoxylin-eosin (HE) staining and Masson staining, immunohistochemical method were used to observe the neointimal hyperplasia, the migration of smooth muscle cells and and vascular remodeling of the vein bypass graft. The expression changes of NGAL, matrix metalloprotenase (MMP)9, MMP2 and tissue inhibitor of metalloproteinase (TIMP)1 in different periods of the vein bypass graft was tested.
Results
By HE and Masson staining, with the passing of modeling time, degradation of collagen matrix in the vein graft, gradually thickening of muscle fibers and the migration to the inner membrance and vascular remodeling caused the vascular stenosis. By immunohistochemistry, NGAL, MMP9 and MMP2 of normal vein in the model were seldom expressed and even did not express. At 14 days after the modeling, NGAL expression in the membrane layer of blood vessels began to appear, peaked at postoperative 30 days, and began to appear in the inner membrance. MMP9, MMP2 expression began to appear at postoperative 7 days, peaked at postoperative 14 days, and tended to decline at postoperative 30 days. TIMP1 expression was less in normal vascular walls and at the 14 days after the modeling, expression peaked in the vein graft.
Conclusion
NGAL, MMP9, MMP2 and TIMP1 may be involved in the formation of early vascular graft restenosis. NGAL as initiator, results in the expression of MMP9 and MMP2, and participates in the degradation of collagen matrix and the migration of smooth muscle cells in vein grafts. TIMP1 as a negative factor, may play an important role in maintaining their own balance.
ObjectiveThe tissue engineered osteochondral integration of multi-layered scaffold was prepared and the related mechanical properties and biological properties were evaluated to provide a new technique and method for the repair and regeneration of osteochondral defect.MethodsAccording to blend of different components and proportion of acellular cartilage extracellular matrix of pig, nano-hydroxyapatite, and alginate, the osteochondral integration of multi-layered scaffold was prepared by using freeze-drying and physical and chemical cross-linking technology. The cartilage layer was consisted of acellular cartilage extracellular matrix; the middle layer was consisted of acellular cartilage extracellular matrix and alginate; and the bone layer was consisted of nano-hydroxyapatite, alginate, and acellular cartilage extracellular matrix. The biological and mechanics characteristic of the osteochondral integration of multi-layered scaffold were evaluated by morphology observation, scanning electron microscope observation, Micro-CT observation, porosity and pore size determination, water absorption capacity determination, mechanical testing (compression modulus and layer adhesive strength), biocompatibility testing [L929 cell proliferation on scaffold assessed by MTT assay, and growth of green fluorescent protein (GFP)-labeled Sprague Dawley rats’ bone marrow mesenchumal stem cells (BMSCs) on scaffolds].ResultsGross observation and Micro-CT observation showed that the scaffolds were closely integrated with each other without obvious discontinuities and separation. Scanning electron microscope showed that the structure of the bone layer was relatively dense, while the structure of the middle layer and the cartilage layer was relatively loose. The pore structures in the layers were connected to each other and all had the multi-dimensional characteristics. The porosity of cartilage layer, middle layer, and bone layer of the scaffolds were 93.55%±2.90%, 93.55%±4.10%, and 50.28%±3.20%, respectively; the porosity of the bone layer was significantly lower than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The pore size of the three layers were (239.66±35.28), (153.24±19.78), and (82.72±16.94) μm, respectively, showing significant differences between layers (P<0.05). The hydrophilic of the three layers were (15.14±3.15), (13.65±2.98), and (5.32±1.87) mL/g, respectively; the hydrophilic of the bone layer was significantly lower than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The compression modulus of the three layers were (51.36±13.25), (47.93±12.74), and (155.18±19.62) kPa, respectively; and compression modulus of the bone layer was significantly higher than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The osteochondral integration of multi-layered scaffold was tightly bonded with each layer. The layer adhesive strength between the cartilage layer and the middle layer was (18.21±5.16) kPa, and the layer adhesive strength between the middle layer and the bone layer was (16.73±6.38) kPa, showing no significant difference (t=0.637, P=0.537). MTT assay showed that L929 cells grew well on the scaffolds, indicating no scaffold cytotoxicity. GFP-labeled rat BMSCs grew evenly on the scaffolds, indicating scaffold has excellent biocompatibility.ConclusionThe advantages of three layers which have different performance of the tissue engineered osteochondral integration of multi-layered scaffold is achieved double biomimetics of structure and composition, lays a foundation for further research of animal in vivo experiment, meanwhile, as an advanced and potential strategy for osteochondral defect repair.
Objective To manufacture a poly (lactic-co-glycolic acid) (PLGA) scaffold by low temperature deposition three-dimensional (3D) printing technology, prepare a PLGA/decellularized articular cartilage extracellular matrix (DACECM) cartilage tissue engineered scaffold by combining DACECM, and further investigate its physicochemical properties. Methods PLGA scaffolds were prepared by low temperature deposition 3D printing technology, and DACECM suspensions was prepared by modified physical and chemical decellularization methods. DACECM oriented scaffolds were prepared by using freeze-drying and physicochemical cross-linking techniques. PLGA/DACECM oriented scaffolds were prepared by combining DACECM slurry with PLGA scaffolds. The macroscopic and microscopic structures of the three kinds of scaffolds were observed by general observation and scanning electron microscope. The chemical composition of DACECM oriented scaffold was analyzed by histological and immunohistochemical stainings. The compression modulus of the three kinds of scaffolds were measured by biomechanical test. Three kinds of scaffolds were embedded subcutaneously in Sprague Dawley rats, and HE staining was used to observe immune response. The chondrocytes of New Zealand white rabbits were isolated and cultured, and the three kinds of cell-scaffold complexes were prepared. The growth adhesion of the cells on the scaffolds was observed by scanning electron microscope. Three kinds of scaffold extracts were cultured with L-929 cells, the cells were cultured in DMEM culture medium as control group, and cell counting kit 8 (CCK-8) was used to detect cell proliferation. Results General observation and scanning electron microscope showed that the PLGA scaffold had a smooth surface and large pores; the surface of the DACECM oriented scaffold was rough, which was a 3D structure with loose pores and interconnected; and the PLGA/DACECM oriented scaffold had a rough surface, and the large hole and the small hole were connected to each other to construct a vertical 3D structure. Histological and immunohistochemical qualitative analysis demonstrated that DACECM was completely decellularized, retaining the glycosaminoglycans and collagen typeⅡ. Biomechanical examination showed that the compression modulus of DACECM oriented scaffold was significantly lower than those of the other two scaffolds (P<0.05). There was no significant difference between PLGA scaffold and PLGA/DACECM oriented scaffold (P>0.05). Subcutaneously embedded HE staining of the three scaffolds showed that the immunological rejections of DACECM and PLGA/DACECM oriented scaffolds were significantly weaker than that of the PLGA scaffold. Scanning electron microscope observation of the cell-scaffold complex showed that chondrocytes did not obviously adhere to PLGA scaffold, and a large number of chondrocytes adhered and grew on PLGA/DACECM oriented scaffold and DACECM oriented scaffold. CCK-8 assay showed that with the extension of culture time, the number of cells cultured in the three kinds of scaffold extracts and the control group increased. There was no significant difference in the absorbance (A) value between the groups at each time point (P>0.05). Conclusion The PLGA/DACECM oriented scaffolds have no cytotoxicity, have excellent physicochemical properties, and may become a promising scaffold material of tissue engineered cartilage.
ObjectiveAlthough evidence links idiopathic pulmonary fibrosis (IPF) and diabetes mellitus (DM), the exact underlying common mechanism of its occurrence is unclear. This study aims to explore further the molecular mechanism between these two diseases. MethodsThe microarray data of idiopathic pulmonary fibrosis and diabetes mellitus in the Gene Expression Omnibus (GEO) database were downloaded. Weighted Gene Co-Expression Network Analysis (WGCNA) was used to identify co-expression genes related to idiopathic pulmonary fibrosis and diabetes mellitus. Subsequently, differentially expressed genes (DEGs) analysis and three public databases were employed to analyze and screen the gene targets related to idiopathic pulmonary fibrosis and diabetes mellitus. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by Metascape. In addition, common microRNAs (miRNAs), common in idiopathic pulmonary fibrosis and diabetes mellitus, were obtained from the Human microRNA Disease Database (HMDD), and their target genes were predicted by miRTarbase. Finally, we constructed a common miRNAs-mRNAs network by using the overlapping genes of the target gene and the shared gene. ResultsThe results of common gene analysis suggested that remodeling of the extracellular matrix might be a key factor in the interconnection of DM and IPF. Finally, hub genes (MMP1, IL1R1, SPP1) were further screened. miRNA-gene network suggested that has-let-19a-3p may play a key role in the common molecular mechanism between IPF and DM. ConclusionsThis study provides new insights into the potential pathogenic mechanisms between idiopathic pulmonary fibrosis and diabetes mellitus. These common pathways and hub genes may provide new ideas for further experimental studies.
ObjectiveTo investigate the differential expression of transient receptor potential vanilloid receptor 4 (TRPV4) protein in the osteoarthritis (OA) and normal cartilages, and explore the role of TRPV4 in the prevention and treatment of OA.MethodsThe cartilage tissues from the patients of knee OA (OA group) and femoral neck fracture (control group) were taken. In OA group, there were 6 males and 9 females; the age ranged from 55 to 78 years (mean, 69 years); the Kellgren-Lawrence (K-L) score was 3.0±0.8. In control group, there were 5 males and 10 females; the age ranged from 57 to 91 years (mean, 71 years). There was no significant difference in gender and age between the two groups (P>0.05). Western blot, real-time fluorescence quantitative PCR, Masson staining, and immunohistochemical staining were used to detect the difference in protein and mRNA expressions of TRPV4 between the OA and normal cartilages. Then the relationship between the K-L score of OA and the rate of TRPV4-positive cells was analyzed.ResultsThe relative expression of TRPV4 protein and mRNA in OA group were 0.454±0.199 and 2.951±1.200, which were higher than those in control group (0.165±0.074, 1.437±0.682). The difference in relative expression of TRPV4 protein was significant (t=2.718, P=0.026). Histology observation showed that the chondrocytes arranged disorderly in OA group, the structure of extracellular matrix was abnormal, and the cartilage defect reached the deep layer. There were more TRPV4-positive cells in the degenerated tissue, and the rate of TRPV4-positive cells was 37.353%±13.496%. The chondrocytes were arranged well in control group, and the rate of TRPV4-positive cells was only 9.642%±3.284%. There was a significant difference between the two groups (t=7.491, P=0.000). The rate of TRPV4-positive cells in OA group was positively correlated with the OA K-L score (r=0.775, P=0.001).ConclusionThe TRPV4 expression increased in OA cartilages that may contribute to the development of OA.
ObjectiveTo observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.MethodsChondrocytes from the healthy articular cartilage tissue of pig were isolated, cultured, and passaged. The 3rd passage chondrocytes were labeled by PKH26. After MTT demonstrated that PKH26 had no influence on the biological activity of chondrocytes, labeled and unlabeled chondrocytes were seeded on ACECM oriented scaffold and cultivated. The adhesion, growth, and distribution were evaluated by gross observation, inverted microscope, and fluorescence microscope. Scanning electron microscope was used to observe the cellular morphology after cultivation for 3 days. Type Ⅱ collagen immunofluorescent staining was used to check the secretion of extracellular matrix. In addition, the complex of labeled chondrocytes and ACECM oriented scaffold (cell-scaffold complex) was transplanted into the subcutaneous tissue of nude mouse. After transplantation, general physical conditions of nude mouse were observed, and the growth of cell-scaffold complex was observed by molecular fluorescent living imaging system. After 4 weeks, the neotissue was harvested to analyze the properties of articular cartilage tissue by gross morphology and histological staining (Safranin O staining, toluidine blue staining, and typeⅡcollagen immunohistochemical staining).ResultsAfter chondrocytes that were mainly polygon and cobblestone like shape were seeded and cultured on ACECM oriented scaffold for 7 days, the neotissue was translucency and tenacious and cells grew along the oriented scaffold well by inverted microscope and fluorescence microscope. In the subcutaneous microenvironment, the cell-scaffold complex was cartilage-like tissue and abundant cartilage extracellular matrix (typeⅡcollagen) was observed by histological staining and typeⅡcollagen immunohistochemical staining.ConclusionACECM oriented scaffold is benefit to the cell adhesion, proliferation, and oriented growth and successfully constructes the tissue engineered cartilage in nude mouse model, which demonstrates that the ACECM oriented scaffold is promise to be applied in cartilage tissue engineering.
ObjectiveTo review the properties of bio-derived hydrogels and their application and research progress in tissue engineering.
MethodsThe literature concerning the biol-derived hydrogels was extensively reviewed and analyzed.
ResultsBio-derived hydrogels can be divided into single-component hydrogels (collagen,hyaluronic acid,chitosan,alginate,silk fibroin,etc.) and multi-component hydrogels[Matrigel,the extract of extracellular matrix (ECM),and decellularized ECM].They have favorable biocompatibility and bioactivity because they are mostly extracted from the ECM of biological tissue.Among them,hydrogels derived from decellularized ECM,whose composition and structure are more in line with the requirements of bionics,have incomparable advantages and prospects.This kind of scaffold is the closest to the natural environment of the cell growth.
ConclusionBio-derived hydrogels have been widely used in tissue engineering research.Although there still exist many problems,such as the poor mechanical properties,rapid degradation,the immunogenicity or safety,vascularization,sterilization methods,and so on,with the deep-going study of optimization mechanism,desirable bio-derived hydrogels could be obtained,and thus be applied to clinical application.
ObjectiveTo summarize recent progress in adipose tissue acting as a more efficient and ideal therapy to facilitate wound repair and evaluate the therapeutic values of adipose tissue.MethodsThe related literature about adipose tissue for wound healing in recent years was reviewed and analyzed.ResultsEnormous studies focus on the capacity of adipose tissue to accelerate wound healing including cellular components, extracellular matrix, and paracrine signaling have been investigated.ConclusionAdipose tissue has generated great interest in recent years because of unique advantages such as abundant and accessible source, thriven potential to enhance the regeneration and repair of damaged tissue. However, there is still a need to explore the mechanism that adipose tissue regulates cellular function and tissue regeneration in order to facilitate clinical application of adipose tissue in wound healing.
ObjectiveTo summarize the role of ionized free calcium/calmodulin/calmodulin-dependent protein kinase Ⅱ (Ca2+/CaM/CaMKⅡ) signaling pathway in liver fibrosis so as to provide a theoretical basis for the treatment of liver fibrosis. MethodThe recent literature relevant research on the role of Ca2+/CaM/CaMKⅡ signaling pathway in the process of liver fibrosis both domestically and internationally was reviewed. ResultsThe Ca2+/CaM/CaMKⅡ signaling pathway played a bidirectional regulatory role in the process of liver fibrosis, potentially facilitating the activation of hepatic stellate cells and triggering hepatocyte apoptosis through synergistic transforming growth factor-β1 and platelet-derived growth factor pathways. ConclusionsAt present, there is very little research on the role of Ca2+/CaM/CaMKⅡ signaling pathway in the process of liver fibrosis, and there is still insufficient understanding. Future research should focus on the mechanism of this signaling pathway in liver fibrosis, especially its upstream genes or downstream target proteins, which will aid to develop targeted and effective treatment strategies, achieve the reversal of liver fibrosis and even liver cirrhosis, and provide more effective treatment options for patients with liver fibrosis.
