A major factor limiting survival following extensive thermal injury is insufficient availability of donor sites to provide enough skin for the required grafting procedures. Limitation of autologous grafting promotes the usage of allograft skin substitutes to promote wound healing. Here, we investigated the wound healing potential of allograft single layered tissue engineered skin which comprises of either keratinocytes (SLTES-K) or fibroblast (SLTES-F) with fibrin as the delivery system. Results from gross and microscopic evaluation showed our single layered tissue engineered skin constructed with keratinocytes or fibroblast after gamma radiation with the dosage of 2Gy could serve as allograft for the treatment of skin loss.
The emergence of tissue engineering and stem cell research has created a tremendous response amongst scientist in Malaysia. However, despite the enthusiastic to embark on the research we have to carefully divert the research towards our needs. This is due to our responsibility to address the mounting problem of communicable diseases here and a very limited funding. As commercialization is a key objective the combination of products towards treating or diagnosing communicable and non-communicable diseases in the developing country is another important factor. The discussion here is mainly on the evolution of tissue engineering in Malaysia and taking a model of tissue engineering in otolaryngology.
Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering.
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.
A Malaysian family with congenital insensitivity to pain with anhydrosis was diagnosed based on clinical symptoms of chronic ulcers, joint deformities, malunited fractures, anhydrosis, and learning disabilities. We detected a compound heterozygous mutation in exon 16: V709L from the mother and G718S from the father. Two novel mutations were identified: at amino acid 709, a change of G to C at nucleotide 2209 (approximately 2209G to C) causing a valine to leucine substitution (V709L), and at amino acid 718, a change of G to A at nucleotide 2236 (approximately 2236G to A) causing a glycine to serine substitution (G718S). Polymorphisms identified were at nucleotides approximately 2113G to C and approximately 2176T to C.
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.
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.
Our aim of this study was to develop a new methodology for constructing a bilayer human skin equivalent to create a more clinical compliance skin graft composite for the treatment of various skin defects. We utilized human plasma derived fibrin as the scaffold for the development of a living bilayer human skin equivalent: fibrin-fibroblast and fibrin-keratinocyte (B-FF/FK SE). Skin cells from six consented patients were culture-expanded to passage 1. For B-FF/FK SE formation, human fibroblasts were embedded in human fibrin matrix and subsequently another layer of human keratinocytes in human fibrin matrix was stacked on top. The B-FF/FK SE was then transplanted to athymic mice model for 4 weeks to evaluate its regeneration and clinical performance. The in vivo B-FF/FK SE has similar properties as native human skin by histological analysis and expression of basal Keratin 14 gene in the epidermal layer and Collagen type I gene in the dermal layer. Electron microscopy analysis of in vivo B-FF/FK SE showed well-formed and continuous epidermal-dermal junction. We have successfully developed a technique to engineer living bilayer human skin equivalent using human fibrin matrix. The utilization of culture-expanded human skin cells and fibrin matrix from human blood will allow a fully autologous human skin equivalent construction.
The objectives of this study were to determine the optimum concentration of basic fibroblast growth factor (bFGF) in foetal bovine serum (FBS) or human serum (HS) supplemented medium for adult human nasal septum chondrocyte culture and to evaluate the potential of cartilage regeneration.
Hearing loss is a common sensory deficit in humans. The hearing loss may be conductive, sensorineural, or mixed, syndromic or nonsyndromic, prelingual or postlingual. Due to the complexity of the hearing mechanism, it is not surprising that several hundred genes might be involved in causing hereditary hearing loss. There are at least 82 chromosomal loci that have been identified so far which are associated with the most common type of deafness--non-syndromic deafness. However, there are still many more which remained to be discovered. Here, we report the mapping of a locus for autosomal recessive, non-syndromic deafness in a family in Malaysia. The investigated family (AC) consists of three generations--parents who are deceased, nine affected and seven unaffected children and grandchildren. The deafness was deduced to be inherited in an autosomal recessive manner with 70% penetrance. Recombination frequencies were assumed to be equal for both males and females. Using two-point lod score analysis (MLINK), a maximum lod score of 2.48 at 0% recombinant (Z = 2.48, theta = 0%) was obtained for the interval D14S63-D14S74. The haplotype analysis defined a 14.38 centiMorgan critical region around marker D14S258 on chromosome 14q23.2-q24.3. There are 16 candidate genes identified with positive expression in human cochlear and each has great potential of being the deaf gene responsible in causing non-syndromic hereditary hearing loss in this particular family. Hopefully, by understanding the role of genetics in deafness, early interventional strategies can be undertaken to improve the life of the deaf community.
Treatment and management of congenital as well as post-traumatic trachea stenosis remains a challenge in pediatric surgery. The aim of this study was to reconstruct a trachea with human nasal septum chondrocytes by using the combination of biodegradable hydrogel and non-biodegradable high-density polyethylene (HDP) as the internal predetermined shape scaffold.
This study was to investigate the effects of insulin-transferrin-selenium (ITS) on the proliferation and quantitative gene expression of adult human nasal septum chondrocytes in monolayer culture expansion and the formation of tissue engineered hyaline cartilage. Effects of ITS on human nasal septum chondrocytes monolayer culture expansion and gene expression were evaluated in various culture media either added with 2% fetal bovine serum (FBS) or 1 ng/mL basic fibroblast growth factor plus 1 ng/mL transforming growth factor or both serum and growth factors supplementation in comparison with medium added with 10%FBS. Chondrocytes cultured in medium added with 2% fetal bovine serum and growth factors either supplemented with or without ITS were then mixed with pluronic F-127 hydrogel for in vivo tissue engineered cartilage formation in nude mice model. Engineered tissues were removed after 8 weeks of implantation and evaluated with histological staining, immunohistochemistry, transmission electron microscopy and quantitative gene expression analysis. ITS promoted human chondrocytes proliferation and reduced chondrocytes dedifferentiation in media supplemented with serum and growth factors. ITS with 2% FBS and growth factors provided 15-fold increased in chondrocytes number by the end of the culture period compared to the standard culture medium used in chondrocytes culture (medium added with 10% FBS). Engineered tissue resulted from ITS supplementation demonstrated higher quality of cartilage formation. In conclusion, our study has demonstrated the benefits of ITS supplementation in human chondrocytes monolayer culture and tissue engineering cartilage formation.
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.
Chitosan has similar structure to glycosaminoglycans in the tissue, thus may be a good candidates as tissue engineering scaffold. However, to improve their cell attachment ability, we try to incorporate this natural polymer with collagen by combining it via cross-linking process. In this preliminary study we evaluate the cell attachment ability of chitosan-collagen scaffold versus chitosan scaffold alone. Chitosan and collagen were dissolved in 1% acetic acid and then were frozen for 24 hours before the lyophilizing process. Human skin fibroblasts were seeded into both scaffold and were cultured in F12: DMEM (1:1). Metabolic activity assay were used to evaluate cell attachment ability of scaffold for a period of 1, 3, 7 and 14 days. Scanning electron micrographs shows good cell morphology on chitosan-collagen hybrid scaffold. In conclusion, the incorporation of collagen to chitosan will enhance its cell attachment ability and will be a potential scaffold in tissue engineering.
Tricalcium phosphate/hydroxyapatite (TCP/HA), hydroxyapatite (HA), chitosan and calcium sulphate (CaSO4) were studied and evaluated for possible bone tissue engineered construct acting as good support for osteogenic cells to proliferate, differentiate, and eventually spread and integrate into the scaffold. Surface morphology visualized by SEM showed that scaffold materials with additional fibrin had more cell densities attached than those without, depicting that the presence of fibrin and collagen fibers were truly a favourite choice of cells to attach. In comparison of various biomaterials used incorporated with fibrin, TCP/HA had the most cluster of cells attached.
Bone marrow harvested by aspiration contains connective tissue progenitor cells which can be selectively isolated and induced to express bone phenotype in vitro. The osteoblastic progenitor can be estimated by counting the number of cells attach using the haemacytometer. This study was undertaken to test the hypothesis that human aging is associated with a significant change on the number of osteoblastic progenitors in the bone marrow. Bone marrow aspirates were harvested from 38 patients, 14 men (age 11-70) and 24 women (age 10-70) and cultured in F12: DMEM (1:1). In total 15 bone marrow samples have been isolated from patients above 40 years old (men/women) of age. Fourteen (93.3%) of this samples failed to proliferate. Only one (6.7%) bone marrow sample from a male patient, aged 59 years old was successfully cultured. Seventy percent (16/23) of the samples from patient below than 40 years old were successfully cultured. However, our observation on the survival rate for cells of different gender from patient below 40 years old does not indicate any significant difference. From this study, we conclude that the growth of bone marrow stromal cells possibly for bone engineering is better from bone marrow aspirates of younger patient.
Skin is the largest organ in human system and plays a vital role as a barrier against environment and pathogens. Skin regeneration is important in tissue engineering especially in cases of chronic wounds. With the tissue engineering technology, these skins equivalent have been use clinically to repair burns and wounds. Consented redundant skin samples were obtained from patients aged 9 to 65 years old. Skin samples were digested with dispase, thus separating the epidermis and the dermis layer. The epidermis layer was trypsinized and cultured in DKSFM in 6-well plate at 37 degrees C and 5% CO2. Once confluent, the culture were trypsinized and the cells were pooled. Cells were counted using haemacytometer. Doubling time and viability were calculated and analysed. From the result, we conclude that doubling time and viability of in vitro keratinocytes cultured in DKSFM media is not age dependant.
We have previously formulated an optimized human chondrocytes growth medium based on 2% fetal bovine serum supplementation. For clinical usage, the animal serum must be replaced by patient own serum. We investigated the effects of human serum concentration for human nasal septum chondrocytes monolayer culture and cartilage reconstruction. Human serum demonstrated a dose dependent manner in promoting chondrocytes growth and cartilage engineering.
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.