The skin protects the body from external barriers. Certain limitations exist in the development of technologies to rapidly prepare skin substitutes that are therapeutically effective in surgeries involving extensive burns and skin transplantation. Herein, we fabricated a structure similar to the skin layer by using skin-derived decellularized extracellular matrix (dECM) with bioink, keratinocytes, and fibroblasts using 3D-printing technology. The therapeutic effects of the produced skin were analyzed using a chimney model that mimicked the human wound-healing process. The 3D-printed skin substitutes exhibited rapid re-epithelialization and superior tissue regeneration effects compared to the control group. These results are expected to aid the development of technologies that can provide customized skin-replacement tissues produced easily and quickly via 3D-printing technology to patients.

The purpose of this study was to evaluate the effect of porcine cancellous bone as a scaffold in a rat calvarial defect model. Critical-sized defects were created in 30 male Sprague-Dawley rats. The animals were divided into critical defect (CD, n=10), β-tricalcium phosphate (TCP) graft (BT, n=10) and porcine cancellous bone graft (PCB, n=10) groups. Each defect was filled with β-TCP mixed with fibrin glue or porcine cancellous bone powder mixed with fibrin glue. In the CD group, the defect was left empty. All rats were sacrificed at 8 weeks after bone graft surgery, and bone formation was evaluated by gross observation, plain radiography, micro-computed tomography scanning and histological evaluation. Repair of bone defect was the least in the CD group, and significant new bone formation was observed in the PCB group. Grafting of porcine cancellous bone was more efficient for regenerating new bone than grafting β-TCP.

The effectiveness of small-diameter vascular grafts depends on their antithrombogenic properties and ability to undergo accelerated endothelialization. The extreme hydrophobic nature of poly(ε-caprolactone) (PCL) hinders vascular tissue integration, limiting its use in medical implants. To enhance the antithrombogenicity of PCL as a biomaterial, we grafted 2-aminoethyl methacrylate (AEMA) hydrochloride onto the PCL surface using gamma irradiation; developed a biodegradable heparin-immobilized PCL nanofibrous scaffold using gamma irradiation and N-(3-dimethylaminopropyl)-N′-ethyl carbodiimide hydrochloride/N-hydroxysuccinimide reaction chemistry; and incorporated vascular endothelial growth factor (VEGF) into the scaffold to promote vascular endothelial cell proliferation and prevent thrombosis on the vascular grafts. We assessed the physicochemical properties of PCL, heparin-AEMA-PCL (H-PCL), and VEGF-loaded heparin-AEMA-PCL (VH-PCL) vascular grafts using scanning electron microscopy, attenuated total reflection–Fourier transform infrared spectroscopy, toluidine blue O staining, and fibrinogen adsorption and surface wettability measurement. In addition, we implanted the vascular grafts into 24-month-old Sprague Dawley rats and evaluated them for 3 months. The H-PCL and VH-PCL vascular grafts improved the recovery of blood vessel function by promoting the proliferation of endothelial cells and preventing thrombosis in clinical and histological evaluation, indicating their potential to serve as functional vascular grafts in vascular tissue engineering.

The periosteum contains multipotent cells that can differentiate into osteoblasts and chondrocytes. Cultured periosteum-derived cells (PDCs) have an osteogenic capacity. The purpose of this study was to evaluate the interaction of PDCs with bone graft biomaterial. After cell isolation from the calvarial periosteum of Sprague-Dawley rats, cultured PDCs were placed in critical-sized calvarial defects with beta-tricalcium phosphate (β-TCP). All rats were sacrificed 8 weeks after bone graft surgery, and the bone regenerative ability of bone grafting sides was evaluated by plain radiography, micro-computed tomography (CT), and histological examination. PDCs grafted with β-TCP displayed enhanced calcification in the defect site, density of regenerated bone and new bone formation within the defect and its boundaries. Furthermore, these PDCs more efficiently regenerated new bone as compared to grafted β-TCP only. The results suggest that cultured PDCs have the potential to promote osteogenesis in bone defects.

Miniature pigs are widely used in experiments related to pulmonary disease because of their similarities with humans. However, there are not enough data about normal lung function in miniature pigs. Thus, in this study, we investigated normal lung function in miniature pigs with lung ventilation/perfusion scintigraphy and evaluated the availability of this method. Three male miniature pigs weighing 30-35 kg were used. After general anesthesia, ventilation scintigraphy was performed with 100 MBq of Tc-macro aggregated albumin (MAA). The functional contribution of the right lung was about 55%, and left lung was about 45%, similar to humans. Lung ventilation/perfusion scintigraphy was very useful in evaluating the normal lung function of miniature pigs because it was a non-invasive procedure (no tissue damage was involved), took a short time and was easy to perform. In conclusion, miniature pigs are similar to humans in functional contributions of the lung, and this method will be helpful in future pulmonary disease studies involving miniature pigs.