Effect of cell density on formation of three-dimensional cartilaginous constructs using fibrin & human osteoarthritic chondrocytes

Background & objectives: Seeding density is one of the major parameters affecting the quality of tissue-engineered cartilage. The objective of this study was to evaluate different seeding densities of osteoarthritis chondrocytes (OACs) to obtain the highest quality cartilage. Methods: The OACs were expanded from passage 0 (P0) to P3, and cells in each passage were analyzed for gross morphology, growth rate, RNA expression and immunochemistry (IHC). The harvested OACs were assigned into two groups: low (1×10[7] cells/ml) and high (3×10[7] cells/ml) cell density. Three-dimensional (3D) constructs for each group were created using polymerised fibrin and cultured for 7, 14 and 21 days in vitro using chondrocyte growth medium. OAC constructs were analyzed with gross assessments and microscopic evaluation using standard histology, IHC and immunofluorescence staining, in addition to gene expression and biochemical analyses to evaluate tissue development. Results: Constructs with a high seeding density of 3×10[7] cells/ml were associated with better quality cartilage-like tissue than those seeded with 1×10[7] cells/ml based on overall tissue formation, cell association and extracellular matrix distribution. The chondrogenic properties of the constructs were further confirmed by the expression of genes encoding aggrecan core protein and collagen type II. Interpretation & conclusions: Our results confirmed that cell density was a significant factor affecting cell behaviour and aggregate production, and this was important for establishing good quality cartilage.

Differential gene expression of human adipose-derived stem cells in osteogenic induction

Human adipose-derived stem cells (HADSC) have demonstrated the capacity of differentiating into bone depending on the specific induction stimuli and growth factors. However, investigation on stem cell characteristic after osteogenic differentiation is still lacking. The goal of this study was to investigate the differential expression of sternness and osteogenic genes in non-induced HADSC compared with HADSC after osteogenic induction using quantitative Real Time RT-PCR. Our results showed that OCT-4, REX-1, FZD9, OSC, RUNX, and ALP were up regulated after osteogenic induction. This may indicated that HADSCs after osteogenic induction still possessed some stemness properties.

Tissue engineering provides the potential to replace and regenerate

Tissue engineering applies the principle of engineering and life sciences towards the development of biological substitute that restore, maintain or improve tissue or organ function. Scientists grow tissues or organs in vitro and implant them when the body is unable to prompt into healing itself. This presentation aims to highlight the potential clinical application of engineered tissues being researched on at the Tissue Engineering Centre, Universiti Kebangsaan Malaysia Medical Centre.

Derivation of neurospheres from bone marrow stromal cells

Nerve stem cells have a unique characteristic in that they form spherical aggregates, also termed neurospheres, in vitro. The study demonstrated the successful derivation of these neurospheres from bone marrow culture. Their plasticity as nerve stem cells was confirmed. The findings further strengthens the pluripotency of cell populations within the bone marrow.

Usage of allogeneic single layered tissue engineered skin enhance wound treatment in sheep

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.

Living bilayered human skin equivalent: promising potentials for wound healing

The angiogenic potential of native skin (NS), keratinocytes single skin equivalent (SSE-K), fibroblasts single skin equivalent (SSE-F) and bilayered skin equivalent secreting angiogenic growth factors such as transforming growth factor beta1 (TGF-beta1), vascular endothelial growth factor (VEGF), keratinocyte growth factor (KGF) and basic fibroblast growth factor (bFGF) in the in vitro systems at 24, 48, 72 hours and 7 days was compared using Enzyme-Linked Immunosorbent Assay (ELISA). Bilayered skin equivalent exhibit highest release of growth factors within 24 hours to 7 days of culture compared to NS, SSE-K and SSE-F. This proved the potential of bilayered skin equivalent in producing and sustaining growth factors release to enhance angiogenesis, fibroblasts proliferation, matrix deposition, migration and growth of keratinocytes.

A scanning electron microscopic study of in vivo tissue engineered respiratory epithelium in sheep

Normal tracheal mucociliary clearance is the key to maintaining the health and defense of respiratory airway. Therefore the present of cilia and mucous blanket are important for tracheal epithelium to function effectively. In the present study, we prepared a tissue engineered respiratory epithelium construct (TEREC) made of autologous respiratory epithelium cells, fibroblast and fibrin from sheep owns blood which replaced a created tracheal mucosal defect. Scanning electron microscopy (SEM) showed encouraging result where immature cilia were present on the surface of TEREC. This result indicates that engineered respiratory epithelium was able to function as normal tissue.

Approaches to deriving Schwann cells from human bone marrow for neural tube regeneration in a clinical setting

Bone marrow derived Mesenchymal stem cells (MSCs) were evaluated as an alternative source for tissue engineering of peripheral nerves. Human MSCs were subjected to a series of treatment with a reducing agent, retinoic acid and a combination of trophic factors. This treated MSCs differentiated into Schwann cells were characterized in vitro via flow cytometry analysis and immunocytochemically. In contrast to untreated MSCs, differentiated MSCs expressed Schwann cell markers in vitro, as we confirmed by flow cytometry analysis and immunocytochemically. These results suggest that human MSCs can be induced to be a substitute for Schwann cells that may be applied for nerve regeneration since it is difficult to grow Schwann cells in vitro.

Tissue engineering research in developing countries, the significant and differences as compared to the developed countries

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.

Scanning electron microscopy of cornea re-epithelization after transplanted with bilayered corneal construct

The present work was to determine the development and re-epithelization of bilayered corneal construct (BCC) in vitro and in vivo using scanning electron microscopy (SEM). The in vitro BCC was transplanted to the rabbit's eye and after 90 days the BCC was harvested and analyzed. The corneas were processed for morphology studies. The result indicates that the BICC that was transplanted for 90 days showed good development and re-epithelization of epithelial layer similar to the normal cornea.

Ex vivo growth of rabbit bulbar, fornix and palpebral conjunctival epithelia in a serum-free and feeder layer-free culture system

This study was conducted to explore the feasibility of culturing conjunctiva epithelial cells in serum-free and feeder layer-free culture system with regard to the cell morphology and immunocytochemistry of the rabbit bulbar, fornix and palpebral conjunctiva epithelia. The results showed that epithelium cells from all the three conjunctiva regions can be cultured in a serum-free and feeder layer-free environment. We obtained highest epithelial growth from fornix region with minimum invasion of fibroblast cells compared to other area. All cultured cells were stained positive for cytokeratin 19 and MUC5AC and negative for cytokeratin 3. These findings suggested that fornix was a better source of cells for the development of tissue engineered conjunctiva for future clinical application.

Sourcing different neuro-progenitor cell for the use of nerve construct

Spinal cord, sciatic nerve, olfactory ensheathing cell and bone marrow derived mesenchymal stem cells were evaluated as an alternative source for tissue engineering of nerve conduit. All cell sources were cultured in alpha-MEM medium. Olfactory Ensheathing Cell (OEC) showed the best result with higher growth kinetic compared to the others. Spinal cord and sciatic nerve were positive for GFAP, OEC were positive for GFAP, S100b and anti-cytokeratin 18 but negative for anti-Human Fibroblast.

Derivation of cochlea hair cell for in vitro expansion and characterization

A potential cure for hearing loss would be to regenerate hair cells by stimulating cells of the damaged inner ear sensory epithelia to proliferate and differentiate into hair cells. Here, we investigated the possibility to isolate, culture-expand and characterize the cells from the cochlea membrane of adult mice. Our results showed that the cultured cells isolated from mouse cochlea membrane were heterogenous in nature. Morphologically there were epithelial like cells, hair cell like, nerve cell like and fibroblastic cells observed in the culture. The cultured cells were immunopositive for specific hair cell markers including Myosin 7a, Calretinin and Espin.

Growth kinetic study on normal and microtic chondrocytes of human auricular cartilage

Chondrocytes were isolated from normal and microtic human auricular cartilage after ear surgery carried out at Universiti Kebangsaan Malaysia Medical Centre. Chondrocytes were cultured and expanded until passage 4. After reached confluence, cultured chondrocytes at each passage (P1, P2, P3 and P4) were harvested and assigned for growth profile analysis. There was no significant difference in cell viability between both normal and microtic samples (p = 0.84). Both samples showed no significant differences for growth profile parameters in terms of growth rate, population doubling time and total number of cell doubling, except in passage 1, where there is significant difference in cell growth rate (p = 0.004). This preliminary data has indicated that chondrocytes from microtic cartilage has the potential to be used in the reconstruction of human pinna in the future.

Isolation techniques of murine bone marrow progenitor cells and their adipogenic, neurogenic and osteogenic differentiation capacity

Bone marrow derived progenitor cells have been widely studied for its multipotent property and have proofed to be an important resource in regenerative medicine. However, the propagation of murine bone marrow appeared to be a great challenge as compared to other mammalian species. In this study, various isolation techniques and the plasticity of the isolated cells were evaluated. Our result shows that magnetic sorting technique yielded the most viable cells and displayed wider differentiation capacity.

Interaction between insulin-like growth factor-1 with other growth factors in serum depleted culture medium for human cartilage engineering

The regulation roles of insulin-like growth factor-1 (IGF-1) with basic fibroblast growth factor (bFGF) and transforming growth factor beta 2 (TGFbeta2) in human nasal septum chondrocytes monolayer culture and cartilage engineering was investigated in this study. The role of IGF-1 with bFGF and TGFbeta2 was investigated by measuring chondrocyte growth kinetic and collagen genes expression. IGF-1 together with bFGF and TGFbeta2 promote cartilage tissue engineering, increase type II collagen expression and enhance the histological features of engineered cartilage.

The effects of autologous human serum on the growth of tissue engineered human articular cartilage

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.

In vitro development of autologous tissue engineered human articular neocartilage for orthopaedic surgery

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.

Autologous human fibrin as the biomaterial for tissue engineering

Patient own fibrin may act as the safest, cheapest and immediate available biodegradable scaffold material in clinical 1 tissue engineering. This study investigated the feasibility of using patient own fibrin isolated from whole blood to construct a new human cartilage, skin and bone. Constructed in vitro tissues were implanted on the dorsal part of the nude mice for in vivo maturation. After 8 weeks of implantation, the engineered tissues were removed for histological analysis. Our results demonstrated autologous fibrin has great potential as clinical scaffold material to construct various human tissues.

Quality evaluation analysis of bioengineered human skin

Our objective is to determine the quality of tissue engineered human skin via immunostaining, RT-PCR and electron microscopy (SEM and TEM). Culture-expanded human keratinocytes and fibroblasts were used to construct bilayer tissue-engineered skin. The in vitro skin construct was cultured for 5 days and implanted on the dorsum of athymic mice for 30 days. Immunostaining of the in vivo skin construct appeared positive for monoclonal mouse anti-human cytokeratin, anti-human involucrin and anti-human collagen type I. RT-PCR analysis revealed loss of the expression for keratin type 1, 10 and 5 and re-expression of keratin type 14, the marker for basal keratinocytes cells in normal skin. SEM showed fibroblasts proliferating in the 5 days in vitro skin. TEM of the in vivo skin construct showed an active fibrocyte cell secreting dense collagen fibrils. We have successfully constructed bilayer tissue engineered human skin that has similar features to normal human skin.