Our preliminary results indicated that fibrin and poly(lactic-co-glycolic acid) (PLGA) hybrid scaffold promoted early chondrogenesis of articular cartilage constructs in vitro. The aim of this study was to evaluate in vivo cartilaginous tissue formation by chondrocyte-seeded fibrin/PLGA hybrid scaffolds. PLGA scaffolds were soaked carefully, in chondrocyte-fibrin suspension, and polymerized by dropping thrombin-calcium chloride (CaCl2) solution. PLGA-seeded chondrocytes were used as a control. Resulting constructs were implanted subcutaneously, at the dorsum of nude mice, for 4 weeks. Macroscopic observation, histological evaluation, gene expression and sulphated-glycosaminoglycan (sGAG) analyses were performed at each time point of 1, 2 and 4 weeks post-implantation. Cartilaginous tissue formation in fibrin/PLGA hybrid construct was confirmed by the presence of lacunae and cartilage-isolated cells embedded within basophilic ground substance. Presence of proteoglycan and glycosaminoglycan (GAG) in fibrin/PLGA hybrid constructs was confirmed by positive Safranin O and Alcian Blue staining. Collagen type II exhibited intense immunopositivity at the pericellular matrices. Chondrogenic properties were further demonstrated by the expression of gene encoded cartilage-specific markers, collagen type II and aggrecan core protein. The sGAG production in fibrin/PLGA hybrid constructs was higher than in the PLGA group. In conclusion, fibrin/PLGA hybrid scaffold promotes cartilaginous tissue formation in vivo and may serve as a potential cell delivery vehicle and a structural basis for articular cartilage tissue-engineering.
Monolayer culture expansion remains as a fundamental step to acquire sufficient number of cells for 3D constructs formation. It has been well-documented that cell expansion is however accompanied by cellular dedifferentiation. In order to promote cell growth and circumvent cellular dedifferentiation, we evaluated the effects of Transforming Growth Factor Beta-2 (TGF-β2), Insulin-like Growth Factor-I (IGF-I) and basic Fibroblast Growth Factor (bFGF) combination on articular chondrocytes culture and 'chondrocytes-fibrin' construct formation. Chondrocytes were serially cultured in: (1) F12:DMEM+10% Foetal Bovine Serum (FBS) with growth factors (FD10GFs), (2) F12:DMEM+2%FBS with the growth factors (FD2GFs) and, (3) F12:DMEM+10%FBS without growth factors (FD) as control. Cultured chondrocytes were evaluated by means of growth kinetics parameters, cell cycle analysis, quantitative phenotypic expression of collagen type II, aggrecan core protein sox-9 and collagen type I and, immunochemistry technique. Harvested chondrocytes were incorporated with plasma-derived fibrin and were polymerized to form the 3D constructs and implanted subcutaneously at the dorsum of athymic nude mice for eight (8) weeks. Resulted constructs were assigned for gross inspections and microscopic evaluation using standard histochemicals staining, immunochemistry technique and, quantitative phenotypic expression of cartilage markers to reassure cartilaginous tissue formation. Growth kinetics performance of chondrocytes cultured in three (3) types of culture media from the most to least was in the following order: FD10GFs>FD2GFs>FD. Following growth kinetics analysis, we decided to use FD10GFs and FD (control) for further evaluation and 'chondrocytes-fibrin' constructs formation. Chondrocytes cultured in FD10GFs preserved the normal diploid state (2c) with no evidence of aneuploidy, haploidy or tetraploidy. Expression of cartilage-specific markers namely collagen type II, aggrecan core protein and sox-9 were significantly higher in FD10GFs when compared to control. After implantation, 'chondrocytes-fibrin' constructs exhibited firm, white, smooth and glistening cartilage-like properties. FD10GFs constructs formed better quality cartilage-like tissue than FD constructs in term of overall cartilaginous tissue formation, cells organization and extracellular matrix distribution in the specimens. Cartilaginous tissue formation was confirmed by the presence of lacunae and cartilage-isolated cells embedded within basophilic ground substance. Presence of proteoglycan was confirmed by positive Safranin O staining. Collagen type II exhibited immunopositivity at the pericellular and inter-territorial matrix area. Chondrogenic properties of the construct were further confirmed by the expression of genes encoding collagen type II, aggrecan core protein and sox9. In conclusion, FD10GFs promotes the proliferation of chondrocytes and formation of good quality 'chondrocytes-fibrin' constructs which may have potential use of matrix-induced cell implantation.
The carriage and antibiotic susceptibility patterns of Staphylococcus aureus in the community were determined. Nasal, throat and axillary swabs were taken from 100 healthy adults and 90 disabled nursing home inmates. Antibiotic disc susceptibility testing was conducted following the NCCLS method. Staphylococcus aureus carriage was noted in 29% of healthy adults and 47.7% of nursing home inmates. Out of 79 strains, resistance to antibiotics were as follows; penicillin (92.4%), genetamicin (2.5%), tetracycline (6.3%), fusidic acid (11.3%), erythromycin (3.8%), pefloxacin (5.1%), mupirocin (3.8%), amikacin (3.8%), ciprofloxacin (2.5%) and chloramphenicol (2.5%). Methicillin-resistant Staphylococcus aureus was not isolated. Multiple colonizations and multi-antibiotic resistant Staphylococcus aureus were shown to occur in healthy individuals without risk factors and not previously hospitalized.
To evaluate the effect of autologous human serum (AHS) versus pooled human serum (PHS) versus foetal bovine serum (FBS) for growth of articular chondrocytes and formation of chondrocytefibrin constructs.
Chondrocytes were isolated from articular cartilage biopsy and were cultivated in vitro. Approximately 30 million of cultured chondrocytes per ml were incorporated with autologous plasma-derived fibrin to form three-dimensional construct. Full-thickness punch hole defects were created in lateral and medial femoral condyles. The defects were implanted either with the autologous 'chondrocytes-fibrin' construct (ACFC), autologous chondrocytes (ACI) or fibrin blank (AF). Sheep were euthanized after 12 weeks. The gross morphology of all defects treated with ACFC implantation, ACI and AF exhibited median scores which correspond to a nearly normal appearance according to the International Cartilage Repair Society (ICRS) classification. ACFC significantly enhanced cartilage repair compared to ACI and AF in accordance with the modified O'Driscoll histological scoring scale. The relative sulphated glycosaminoglycans content (%) was significantly higher (p < 0.05) in ACFC when compared to control groups; ACI vs. fibrin only vs. untreated (blank). Results showed that ACFC implantation exhibited superior cartilage-like tissue regeneration compared to ACI. If the result is applicable to the human, it possibly will improve the existing treatment approaches for cartilage restoration in orthopaedic surgery.
Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous 'chondrocyte-fibrin' construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis. All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O'Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage. Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.
In the centrosymmetric tetra-nuclear title compound, [Sn(4)(C(4)H(9))(8)(C(7)H(5)O(3))(4)O(2)], one of the two independent Sn atoms is five-coordinate in a cis-C(2)SnO(3) trigonal-bipyramidal geometry [C-Sn-C = 142.7 (1)°]; the geometry is distorted owing to a long Sn⋯O(double bond) inter-action [Sn⋯O = 2.862 (1) Å]. The other Sn atom has a bent R(2)Sn skeleton [C-Sn-C = 144.0 (1)°], but the geometry is best regarded as being a trans-C(2)SnO(4) octa-hedron as the Sn-O(single bond) inter-action is shorter [Sn-O = 2.674 (1) Å].
This study was to assess collagen type II and collagen type I gene expression in tissue-engineered human auricular: cartilage formed via tissue engineering technique. Large-scale culture expansions were transformed into 3D in vitro construct and were implanted subcutaneously on the dorsal of athymic mice. After 8 weeks, explanted construct was processed in the same manner of native cartilage to facilitate cells for gene expression analysis. Isolated cells from in vivo construct demonstrated expression of type II collagen gene comparable to native cartilage. This study verified that tissue-engineered auricular cartilage expressed cartilage specific gene, collagen type II after in vivo maturation.
Cartilage is regularly needed for reconstructive surgery. Basic research in tissue engineering is necessary to develop its full potential. We presented here the expression profile of type II collagen gene and type I collagen gene in human auricular monolayer culture expansion. Cultured chondrocytes documented a reduction in the expression level of collagen type II gene whilst collagen type I gene was gradually expressed through all the passages. This study demonstrated that human auricular chondrocytes lose its phenotypic expression during monolayer culture expansion. Further studies are required to enhance cartilage specific gene expression, collagen type II throughout the in vitro culture.
To date there is no optimal approach to reconstruct an external ear. However, advances in tissue engineering technologies have indicated that in vitro autologous elastic cartilage might be of great importance in the future treatment of these patients. The aim of this study was to observe monolayer expansion of auricular cartilage and to evaluate engineered cartilage using standard histochemical study.
Animal serum is commonly used in chondrocytes culture expansion to promote cell proliferation and shorten the time lag before new tissue reconstruction is possible. However, animal serum is not suitable for regeneration of clinical tissue because it has potential risk of viral and prion related disease transmission particularly mad cow disease and foreign protein contamination that can stimulate immune reaction leading to graft rejection. In this context, human serum as homologous supplement has a greater potential as growth promoting agents for human chondrocytes culture.
Autologous cells are usually preferred in treating damaged tissue to avoid risks of immunological rejection and transmitting infectious diseases. Since only limited amount of tissue can be obtained without causing morbidity at the donor site, in vitro expansion of isolated cell is essential in order to acquire sufficient number of cells to reconstruct neocartilage. The aim of this study was to examine whether serial expanded chondrocytes can be use to generate neocartilage in vivo.
Culture media supplemented with animal serum e.g. fetal bovine serum; FBS is commonly used for human culture expansion. However, for clinical application, FBS is restricted as its carry a risk of viral or prion transmission. Engineering autologous cartilage with autologous human serum supplementation is seen as a better solution to reduce the risk of transmitting infectious diseases and immune rejection during cartilage transplantation. The purpose of this study is to establish and compare the effects of 10% autologous human serum (AHS) and 10% FBS on the growth of chondrocytes and the formation of tissue engineered human articular cartilage.
(1) Background: Stem cells in combination with scaffolds and bioactive molecules have made significant contributions to the regeneration of damaged bone tissues. A co-culture system can be effective in enhancing the proliferation rate and osteogenic differentiation of the stem cells. Hence, the aim of this study was to investigate the osteogenic differentiation of human adipose derived stem cells when co-cultured with human osteoblasts and seeded on polycaprolactone (PCL):hydroxyapatite (HA) scaffold; (2) Methods: Human adipose-derived stem cells (ASC) and human osteoblasts (HOB) were seeded in three different ratios of 1:2, 1:2 and 2:1 in the PCL-HA scaffolds. The osteogenic differentiation ability was evaluated based on cell morphology, proliferation rate, alkaline phosphatase (ALP) activity, calcium deposition and osteogenic genes expression levels using quantitative RT-PCR; (3) Results: The co-cultured of ASC/HOB in ratio 2:1 seeded on the PCL-HA scaffolds showed the most positive osteogenic differentiation as compared to other groups, which resulted in higher ALP activity, calcium deposition and osteogenic genes expression, particularly Runx, ALP and BSP. These genes indicate that the co-cultured ASC/HOB seeded on PCL-HA was at the early stage of osteogenic development; (4) Conclusions: The combination of co-culture system (ASC/HOB) and PCL-HA scaffolds promote osteogenic differentiation and early bone formation.
This study was aimed at regenerating autologous elastic cartilage for future use in pediatric ear reconstruction surgery. Specific attentions were to characterize pediatric auricular chondrocyte growth in a combination culture medium and to assess the possibility of elastic cartilage regeneration using human fibrin.
Treatment of articular cartilage lesions remains a clinical challenge. The uses of prosthetic joint replace allograft and/or autograft transplant carry a risk of complications due to infection, loosening of its component, immunological rejection and morbidity at the donor site. There has been an increasing interest in the management of cartilage damages, owing to the introduction of new therapeutic options. Tissue engineering as a method for tissue restoration begins to provide a potential alternative therapy for autologous grafts transplantations. We aimed to evaluate how well a tissue engineered neocartilage implant, consist of human articular chondrocytes cultured with the presence of autologous serum and mixed in a fresh fibrin derived from patient, would perform in subcutaneous implantation in athymic mice.
The osteogenic potential of human adipose-derived stem cells (HADSCs) co-cultured with human osteoblasts (HOBs) using selected HADSCs/HOBs ratios of 1:1, 2:1, and 1:2, respectively, is evaluated. The HADSCs/HOBs were seeded on electrospun three-dimensional poly[(R)-3-hydroxybutyric acid] (PHB) blended with bovine-derived hydroxyapatite (BHA). Monocultures of HADSCs and HOBs were used as control groups. The effects of PHB-BHA scaffold on cell proliferation and cell morphology were assessed by AlamarBlue assay and field emission scanning electron microscopy. Cell differentiation, cell mineralization, and osteogenic-related gene expression of co-culture HADSCs/HOBs were examined by alkaline phosphatase (ALP) assay, alizarin Red S assay, and quantitative real time PCR, respectively. The results showed that co-culture of HADSCs/HOBs, 1:1 grown into PHB-BHA promoted better cell adhesion, displayed a significant higher cell proliferation, higher production of ALP, extracellular mineralization and osteogenic-related gene expression of run-related transcription factor, bone sialoprotein, osteopontin, and osteocalcin compared to other co-culture groups. This result also suggests that the use of electrospun PHB-BHA in a co-culture HADSCs/HOBs system may serve as promising approach to facilitate osteogenic differentiation activity of HADSCs through direct cell-to-cell contact with HOBs.