Tanom Bunaprasert

Development of Collagen/Demineralized Bone Powder Scaffolds and Periosteum-Derived Cells for Bone Tissue Engineering Application

The aim of this study was to investigate physical and biological properties of collagen (COL) and demineralized bone powder (DBP) scaffolds for bone tissue engineering. DBP was prepared and divided into three groups, based on various particle sizes: 75–125 μm, 125–250 μm, and 250–500 μm. DBP was homogeneously mixed with type I collagen and three-dimensional scaffolds were constructed, applying chemical crosslinking and lyophilization. Upon culture with human periosteum-derived cells (PD cells), osteogenic differentiation of PD cells was investigated using alkaline phosphatase (ALP) activity and calcium assay kits. The physical properties of the COL/DBP scaffolds were obviously different from COL scaffolds, irrespective of the size of DBP. In addition, PD cells cultured with COL scaffolds showed significantly higher cell adhesion and proliferation than those with COL/DBP scaffolds. In contrast, COL/DBP scaffolds exhibited greater osteoinductive potential than COL scaffolds. The PD cells with COL/DBP scaffolds possessed higher ALP activity than those with COL scaffolds. PD cells cultured with COL/DBP scaffolds with 250–500 μm particle size yielded the maximum calcium deposition. In conclusion, PD cells cultured on the scaffolds could exhibit osteoinductive potential. The composite scaffold of COL/DBP with 250–500 μm particle size could be considered a potential bone tissue engineering implant.

Tissue engineered muscle implantation for tongue reconstruction: a preliminary report.

Objectives/Hypothesis: Because current tongue reconstructive methods introduce adynamic, variably sensate tissue into the mouth, the critical functions of the tongue in articulation and deglutition may be compromised. The objective of this work was to introduce a combination of myoblasts and scaffolding material into rat hemiglossectomy defects and to examine the extent of neomuscle formation in the reconstructed area, under the hypothesis that the presence of myoblasts leads to formation of new muscle. Study Design: Randomized, prospective animal study. Methods: Myoblasts were harvested from neonatal Lewis rats, and a growth factor enriched collagen gel was prepared. Syngeneic adult animals received either hemiglossectomy alone or reconstruction with one of four experimental reconstructive preparations: collagen gel alone, collagen gel with suspended myoblasts, the gel‐cell combination in undifferentiated muscle construct form by way of tissue culture for 7 days in a preformed mold, or differentiated constructs, cultured in myoblast fusion medium. After 6 or 16 weeks, animal weight gain was recorded, animals were killed, and the tongues harvested. The tissue was examined histologically, and quality of the muscular regenerate was rated on a scale according to predefined criteria. Results: Animals in all groups gained weight appropriately. In groups receiving hemiglossectomy alone or acellular (gel only) reconstruction, there was significant scarring and lack of neomuscle formation. In groups receiving myoblast transplantation, either by way of gel suspension or in the form of undifferentiated or differentiated constructs, muscle quality was superior to controls. Conclusions: Myoblast transplantation into hemiglossectomy defects appears to lead to new muscle formation and does not inhibit normal weight gain in animals after tongue implantation.

Acanthus ebracteatus Vahl. Ethanol Extract Enhancement of the Efficacy of the Collagen Scaffold in Wound Closure: A Study in a Full-Thickness-Wound Mouse Model

Acanthus ebracteatus Vahl. is a Thai herb that is effective in wound healing. We sought to quantitatively determine whether or not the combined application of Acanthus ebracteatus Vahl. and a collagen scaffold will increase wound closure and angiogenesis. Balb/c mice (body weight: 22–25 g) were anesthetized with sodium thiopental. The dorsal skin incision measuring 1.5 × 1.5 cm was made and then deepened using scissors to produce a full-thickness incision down to the level of the panniculus carnosus. The size of the wound was approximately 10% of the total body surface area. The collagen sheet was implanted onto the wound. Animals were divided into 4 major groups as follows: wound with normal saline (W-NSS), wound treated with 0.3 g/kg BW of Acanthus ebracteatus Vahl. extract (W-AE (0.3 g/kg.bw)), wound implanted with collagen scaffold (W-Coll), and wound implanted with collagen scaffold and treated with 0.3 g/kg BW of Acanthus ebracteatus Vahl. (W-Coll-AE combination). On day 14, the W-Coll-AE group showed decreased wound areas and increased capillary vascularity (CV) when compared to the other 3 groups, W-NSS, W-AE0.3, and W-Coll. In the present study, the combination of AE0.3 with collagen showed the best effect on skin angiogenesis and promoted wound closure with less neutrophil infiltration.

Prospective, randomized, controlled trial of proximally based vs. distally based gluteus maximus flap for anal incontinence in cadavers

AbstractPURPOSE: The aim of this study was to compare the lengths of proximally based and distally based gluteus maximus flaps created as for anal sphincter reconstruction in soft human cadavers. METHODS: Twelve soft cadavers were used in this prospective, randomized, controlled study. In each cadaver, a proximally based flap of the gluteus maximus muscle was performed on one side and a distally based flap on the other. All flaps were carefully dissected with neurovascular preservation by one surgeon. After the dissected flap was placed across the anus, the length of the flap that projected beyond the anus was measured. The differences between such lengths of both types of flaps were assessed by paired t-test. RESULTS: The average lengths of the parts that projected beyond the anus for proximally based and distally based flaps were 8.08 and 4.50 (standard deviation, 0.51 and 0.79) cm, respectively. The average difference was 3.58 (standard deviation, 0.51) cm, which was statistically significant (P < 0.001). CONCLUSION: Results showed that proximally based flaps were significantly longer than distally based flaps and that transposition and wrapping around the anus with proximally based flaps were always easily performed without tension. These findings support the use of unilateral proximally based gluteus maximus flaps instead of unilateral or bilateral distally based flaps in patients with anal incontinence. The location of the neurovascular pedicle of the gluteus maximus was consistent at 1 cm superior and lateral to ischial tuberosity. Knowledge of this landmark allows quick and safe dissection of the gluteus maximus flap.

Effect of Polycaprolactone Electrospun Fiber Size on L929 Cell Behavior

Poly (caprolactone) (PCL) was selected as the substance for producing the ultrafine fiber using the eletrospinning process. The effect of the solution concentration on fiber size was studied to determine the condition for preparing PCL fiber mats with desired size range. PCL fiber mats with three different fiber sizes, i.e. 440 nm, 960 nm and 4.6 μm, were prepare and used to evaluate effect of fiber size on cell adhesion and proliferation using L929 as a model cell. The results showed that while fiber size has no effect on initial cell attachment, the mat with medium and large fibers showed higher cell proliferation than the mat with small fiber. Fiber size also played role in prohibiting or accommodating cellular distribution or penetration into the under layer of electrospun fiber mat.

Electrospinning of Polycaprolactone in Dichloromethane/Dimethylformamide Solvent System

Electrospinning of polycaprolactone (PCL) in a mixed solvent of dichloromethane (DCM)/dimethylformamide (DMF) with 1:1 volumetic mixing ratio was studied. The effects of solution concentration (5-30 %w/v), applied voltage (10-25 kV), solution flow rate (0.1-2.0 mL/h) and collecting distance (10, 20 cm) on fiber formation and morphology were investigated. The size of PCL fibers obtained were in the range of 10s nm-2.6 μm with either bead on string or smooth fiber morphology. In this study, the solution concentration strongly affected fiber size exponentially. The fiber size also increased with an increase in solution flow rate. The applied voltage and the collecting distance have no or minimal effect on PCL fiber size.