OBJECTIVE: The development of bio-three-dimensional (bio-3D) printers has led to significant advances in regenerative medicine. Three-dimensional constructs, including spheroids, are maintained by extracellular matrix proteins secreted by cells so that the cells can be cultured in conditions closer to the physiological environment. This study aimed to create a useful 3D construct as a model of the dentin-pulp complex.
METHODS: We examined the expression patterns of extracellular matrix proteins and cell proliferation areas in a 3D construct created using O9-1 cells derived from cranial neural crest cells of mice. The 3D construct was created by sticking the spheroid cultures onto a needle array using a bio-3D printer.
RESULTS: Cell proliferation areas along with characteristic expression of tenascin C and DMP1 were evaluated. The expression of tenascin C and DMP1 was significantly enhanced in the spheroids compared to that in two-dimensional cultures. Moreover, cell proliferation regions and tenascin C expression were confirmed in the outer layer of spheroids in the embryonic stem cell medium, with insignificant DMP1 expression being observed. Interestingly, in a 3D construct cultured in calcification-induction medium, DMP1 expression was promoted, and DMP1-positive cells existed in the outermost layer without overlapping with tenascin C expression.
CONCLUSIONS: The extracellular matrix proteins, tenascin C and DMP1, were expressed in a polarized manner in spheroids and 3D constructs, similar to the findings in the dental papilla. Therefore, these 3D constructs show potential as artificial models for studying odontogenesis.

UNASSIGNED: Stem cell therapy for regenerative medicine has been sincerely investigated, but not still popular although some clinical trials show hopeful results. This therapy is suggested to be a representative candidate such as bone defect due to the accident, iatrogenic resection oncological tumor, congenital disease, and severe periodontitis in oral region. Recently, the Bio-3D printer \"Regenova®\" has been introduced as an innovative three-dimensional culture system, equipped scaffold-free bio-assembling techniques without any biomaterials. Therefore, we expected a mount of bone defect could be repaired by the structure established from this Bio-3D printer using osteogenic potential stem cells.
UNASSIGNED: The gingival tissue (1x1 mm) was removed from the distal part of the lower wisdom tooth of the patients who agreed our study. Human Gingival Mesenchymal Stem Cells (hGMSCs) were isolated from this tissue and cultured, since we confirmed the characteristics such as facile isolation and accelerated proliferation, further, strong potential of osteogenic-differentiation. Spheroids were formed using hGMSC in 96-well plates designed for low cell adhesion. The size of the spheroids was measured, and fluorescent immunostaining was employed to verify the expression of stem cell and apoptosis marker, and extracellular matrix. Following four weeks of bone differentiation, μCT imaging was performed. Calcification was confirmed by alizarin red and von Kossa staining. Fluorescent immunostaining was utilized to assess the expression of markers indicative of advanced bone differentiation.
UNASSIGNED: We have established and confirmed the spheroids (∼600 μm in diameter) constructed from human GMSCs (hGMSCs) still maintain stem cell potentials and osteogenic differentiation abilities from the results that CD73 and not CD34 were expressed as stem cell positive and negative marker, respectively. These spheroids were pilled up like cylindal shape to the \"Kenzan\" platform of Bio-3D printer and cultured for 7days. The cylindal structure originated from compound spheroids were tried to differentiate into bone four weeks with osteogenic induction medium. The calcification of bio-3D printed bone-like structures was confirmed by alizarin red and Von Kossa staining. In addition, μCT analysis revealed that the HU (Hounsfield Unit) of the calcified structures was almost identical to that of trabecular bone. Immunofluorescent staining detected osteocalcin expression, a late-stage bone differentiation marker.
UNASSIGNED: For the first time, we have achieved the construction of a scaffold-free, bone-like luminal structure through the assembly of spheroids comprised of this hGMSCs. This success is sure to be close to the induction of clinical application against regenerative medicine especially for bone defect disease.

Morbidity and mortality rates associated with atherosclerosis-related diseases are increasing. Therefore, developing new research models is important in furthering our understanding of atherosclerosis and investigate novel treatments. Here, we designed novel vascular-like tubular tissues from multicellular spheroids composed of human aortic smooth muscle cells, endothelial cells, and fibroblasts using a bio-3D printer. We also evaluated their potential as a research model for Mönckeberg\'s medial calcific sclerosis. The tubular tissues were sufficiently strong to be handled 1 week after printing and could still be cultured for 3 weeks. Histological assessment showed that calcified areas appeared in the tubular tissues within 1 week after culture in a medium containing inorganic phosphate (Pi) or calcium chloride as the calcification-stimulating factors. Calcium deposition was confirmed using micro-computed tomography imaging. Real-time quantitative reverse transcription polymerase chain reaction analysis revealed that the expression of osteogenic transcription factors increased in calcified tubular tissues. Furthermore, the administration of Pi and rosuvastatin enhanced tissue calcification. The bio-3D printed vascular-like tubular structures, which are composed of human-derived cells, can serve as a novel research model for Mönckeberg\'s medial calcific sclerosis.

Although autogenous bone implantation is considered to be the gold standard for the reconstruction of bone defects, this approach remains challenging when treating extensive bone defects (EBDs). Therefore, artificial materials (AMs) such as artificial bone and scaffolds are often used for treating EBDs. Nevertheless, complications such as material failure, foreign body reaction, and infection are common. To overcome these issues, we aimed to develop a new treatment for an EBD using scaffold-free adipose-derived stromal cells (ADSCs) to fabricate chondrogenic/osteogenic-induced constructs without AMs.
ADSCs were obtained from the subcutaneous adipose tissue of 8-week-old female Wistar rats (n = 3) and assessed to determine their potential for multilineage differentiation into adipocytes (Oil Red O staining), chondrocytes (hematoxylin and eosin, Alcian blue, and Safranin O staining), and osteoblasts (Alizarin red and von Kossa staining). Spheroids (n = 320), each containing 3.0 × 104 ADSCs, were then used to fabricate scaffold-free cell constructs using a bio-3D printer with a needle array. The spheroids and constructs were stimulated with induction medium to induce chondrogenic and osteogenic differentiation. The induced cartilage- and bone-like constructs were finally evaluated using micro-computed tomography (μCT) and histological analysis.
The collected ADSCs were capable of trilineage differentiation, and were successfully used to produce scaffold-free constructs. The fabricated constructs (n = 3) exhibited equivalent strength (load, 195.3 ± 6.1 mN; strength, 39.1 ± 1.2 kPa; and stiffness, 0.09 ± 0.01 N/mm) to that of soft tissues such as the muscles in the uninduced condition. In chondrogenic induction experiments, Alcian blue and Safranin O staining confirmed the differentiation of the constructs into cartilage, and cartilage tissue-like structures were produced. In the osteogenic induction experiment, Alizarin Red and von Kossa staining showed calcium salt deposition, and μCT images confirmed the same calcification level as that of the cortical bone.
Scaffold-free constructs consisting of ADSCs without an AM were fabricated, and cartilage- and bone-like tissues were successfully generated, demonstrating their potential for bone reconstruction.

OBJECTIVE: Cell therapies, such as stem cell suspension injection, are used to treat bronchopleural fistula. Although it is safe and effective, injected cells cannot remain within the bronchioles of the fistula due to cell leakage into the thoracic cavity. Here, we inserted a \'bio plug\' into the fistula, produced using cells and a bio-3D printer, to examine the effectiveness of bio plugs for the closure of bronchopleural fistulas, the optimal cell source and the closure mechanism.
METHODS: Bio plugs were made with mesenchymal stem (stromal) cells derived from bone marrow (MSCBM), fibroblasts and rat lung micro-vessel endothelial cells using a bio-3D printer with different cell mixing ratios. Six groups, according to the presence or absence and the type of bio plugs, were compared. The plugs were inserted into the bronchi of F344 rats. The obstruction ratio and histological and immunohistochemical findings were evaluated.
RESULTS: MSCBM+ rat lung micro-vessel endothelial cell group exhibited a higher obstruction ratio among all groups excluding the MSCBM group (P = 0.039). This group had fibrosis and CD31-positive cells and fewer CD68-positive cells than MSCBM and MSCBM+ fibroblast groups.
CONCLUSIONS: Bio plugs with mixed cells, including stem cells, contribute to bronchial closure in the current experimental setting. Endothelial cells effectively maintain the structure in this model. Although bronchial closure for bronchopleural fistula could not be described as clinical conditions were not reproduced, we collected essential data on bronchial closure; however, further experiments are warranted.

The fabrication of three-dimensional (3D) cardiac tissue using human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is useful not only for regenerative medicine, but also for drug discovery. Here, we report a bio-3D printer that can fabricate tubular cardiac constructs using only human iPSC-CMs. Protocols to evaluate the contractile force and response to electrical stimulation in the cardiac constructs are described. We confirmed that the constructs can be applied for transplantation or drug response testing. In the near future, we expect that the constructs will be used as alternatives for heart transplantation and in animal experiments for new drug development.

UNASSIGNED: Biliary strictures after bile duct injury or duct-to-duct biliary reconstruction are serious complications that markedly reduce patients\' quality of life because their treatment involves periodic stent replacements. This study aimed to create a scaffold-free tubular construct as an interposition graft to treat biliary complications.
UNASSIGNED: Scaffold-free tubular constructs of allogeneic pig fibroblasts, that is, fibroblast tubes, were created using a Bio-3D Printer and implanted into pigs as interposition grafts for duct-to-duct biliary reconstruction.
UNASSIGNED: Although the fibroblast tube was weaker than the native bile duct, it was sufficiently strong to enable suturing. The pigs\' serum hepatobiliary enzyme levels remained stable during the experimental period. Micro-computed tomography showed no biliary strictures, no biliary leakages, and no intrahepatic bile duct dilations. The tubular structure was retained in all resected specimens, and the fibroblasts persisted at the graft sites. Immunohistochemical analyses revealed angiogenesis in the fibroblast tube and absence of extensions of the biliary epithelium into the fibroblast tube\'s lumen.
UNASSIGNED: This study\'s findings demonstrated successful reconstruction of the extrahepatic bile duct with a scaffold-free tubular construct created from pig fibroblasts using a novel Bio-3D Printer. This construct could provide a novel regenerative treatment for patients with hepatobiliary diseases.

BACKGROUND: We have been trying to produce scaffold-free structures for airway regeneration using a bio-3D-printer with spheroids, to avoid scaffold-associated risks such as infection. Previous studies have shown that human umbilical vein endothelial cells (HUVECs) play an important role in such structures, but HUVECs cannot be isolated from adult humans. The aim of this study was to identify alternatives to HUVECs for use in scaffold-free structures.
METHODS: Three types of structure were compared, made of chondrocytes and mesenchymal stem cells with HUVECs, human lung microvascular endothelial cells (HMVEC-Ls), and induced pluripotent stem cell (iPSC)-derived endothelial cells.
RESULTS: No significant difference in tensile strength was observed between the three groups. Histologically, some small capillary-like tube formations comprising CD31-positive cells were observed in all groups. The number and diameters of such formations were significantly lower in the iPSC-derived endothelial cell group than in other groups. Glycosaminoglycan content was significantly lower in the iPSC-derived endothelial cell group than in the HUVEC group, while no significant difference was observed between the HUVEC and HMVEC-L groups.
CONCLUSIONS: HMVEC-Ls can replace HUVECs as a cell source for scaffold-free trachea-like structures. However, some limitations were associated with iPSC-derived endothelial cells.

Neonates with congenital diaphragmatic hernia often require surgical defect closure with a patch. Alternatives to native diaphragmatic tissue are critically needed for this paediatric surgery. The clinical efficacy of mesh patches is limited by complications associated with residual foreign material and by hernia recurrence. In this study, we used a novel bio-3D printer method to generate large scaffold-free tissue patches composed of human cells. The resulting large tissue constructs had high elasticity and strength. Cellular patches were transplanted into rats with surgically created diaphragmatic defects. Rats survived for over 710 days after implantation of tissue constructs. CT confirmed complete tissue integration of the grafts during rat growth. Histology revealed regeneration of muscle structure, neovascularization, and neuronal networks within the reconstructed diaphragms. Our results demonstrate that created cellular patches are a highly safe and effective therapeutic strategy for repairing diaphragmatic defects, and thus pave the way for a clinical trial.