The need for organ and tissue regeneration in patients continues to increase because of a scarcity of donors, as well as biocompatibility issues in transplant immune rejection. To address this, scientists have investigated artificial tissues as an alternative to transplantation. Three-dimensional (3D) bioprinting technology is an additive manufacturing method that can be used for the fabrication of 3D functional tissues or organs. This technology promises to replicate the complex architecture of structures in natural tissue. To date, 3D bioprinting strategies have confirmed their potential practice in regenerative medicine to fabricate the transplantable hard tissues, including cartilage and bone. However, 3D bioprinting approaches still have unsolved challenges to realize 3D hard tissues. In this manuscript, the current technical development, challenges, and future prospects of 3D bioprinting for engineering hard tissues are reviewed.
Bioprinting* ; Cartilage ; Humans ; Methods ; Regeneration ; Regenerative Medicine ; Tissue Donors ; Tissue Engineering*

BACKGROUND: Extracellular vesicles (EVs) exhibit potential as functional biomolecules for tissue regeneration and immunomodulation as they play important roles in the physiological communication between cells. EV internal cargo contains miRNAs, proteins, lipids, and so on. Osteoarthritis (OA) is a common joint disease causing disability owing to impaired joint function and pain. EVs originating from animal cells and tissue matrices are also being considered for OA, in addition to research involving non-steroidal therapeutic agents. However, there are no studies on EVs from marine organisms. Hence, we focused on sea cucumber-derived EVs and conducted experiments to set up an extraction protocol and to demonstrate their efficacy to modulate the inflammatory environment. METHODS: Sea cucumber extracellular matrices (SECMs) were prepared by a decellularization process. Lyophilized SECMs were treated with collagenase and filtered to isolate sea cucumber extracellular vesicles (SEVs). After isolation, we conducted physical characterization and cell activation studies including cytotoxicity, proliferation, and anti-inflammation effect assays. RESULTS: The physical characterization results showed circular SEVs in the size range of 66–480 nm. These SEVs contained large amounts of protein cargo, infiltrated the synoviocyte membrane without damage, and had a suppressive effect on inflammatory cytokines. CONCLUSION This study established an extraction process for EVs from sea cucumber and reported the anti-inflammatory ability of SEVs. Isolated SEVs can be further utilized for tissue regeneration studies and can be compared to various marine or animal-derived EVs.

BACKGROUND: Extracellular vesicles (EVs) exhibit potential as functional biomolecules for tissue regeneration and immunomodulation as they play important roles in the physiological communication between cells. EV internal cargo contains miRNAs, proteins, lipids, and so on. Osteoarthritis (OA) is a common joint disease causing disability owing to impaired joint function and pain. EVs originating from animal cells and tissue matrices are also being considered for OA, in addition to research involving non-steroidal therapeutic agents. However, there are no studies on EVs from marine organisms. Hence, we focused on sea cucumber-derived EVs and conducted experiments to set up an extraction protocol and to demonstrate their efficacy to modulate the inflammatory environment. METHODS: Sea cucumber extracellular matrices (SECMs) were prepared by a decellularization process. Lyophilized SECMs were treated with collagenase and filtered to isolate sea cucumber extracellular vesicles (SEVs). After isolation, we conducted physical characterization and cell activation studies including cytotoxicity, proliferation, and anti-inflammation effect assays. RESULTS: The physical characterization results showed circular SEVs in the size range of 66–480 nm. These SEVs contained large amounts of protein cargo, infiltrated the synoviocyte membrane without damage, and had a suppressive effect on inflammatory cytokines. CONCLUSION This study established an extraction process for EVs from sea cucumber and reported the anti-inflammatory ability of SEVs. Isolated SEVs can be further utilized for tissue regeneration studies and can be compared to various marine or animal-derived EVs.

BACKGROUND: The extracellular matrix (ECM) has many functions, such as segregating tissues, providing support, and regulating intercellular communication. Cartilage-derived ECM (CECM) can be prepared via consecutive processes of chemical decellularization and enzyme treatment. The purpose of this study was to improve and treat osteoarthritis (OA) using porcine knee articular CECM. METHODS: We assessed the rheological characteristics and pH of CECM solutions. Furthermore, we determined the effects of CECM on cell proliferation and cytotoxicity in the chondrocytes of New Zealand rabbits. The inhibitory effect of CECM on tumor necrosis factor (TNF)-a-induced cellular apoptosis was assessed using New Zealand rabbit chondrocytes and human synoviocytes. Finally, we examined the in vivo effects of CECM on inflammation control and cartilage degradation in an experimental OA-induced rat model. The rat model of OA was established by injecting monosodium iodoacetate into the intra-articular knee joint. The rats were then injected with CECM solution. Inflammation control and cartilage degradation were assessed by measuring the serum levels of proinflammatory cytokines and C-telopeptide of type II collagen and performing a histomorphological analysis. RESULTS: CECM was found to be biocompatible and non-immunogenic, and could improve cell proliferation without inducing a toxic reaction. CECM significantly reduced cellular apoptosis due to TNF-a, significantly improved the survival of cells in inflammatory environments, and exerted anti-inflammatory effects. CONCLUSION Our findings suggest that CECM is an appropriate injectable material that mediates OA-induced inflammation.

Larger animal models, such as porcine, have been validated as appropriate models of the human disc with respect to biomechanics and biochemistry. They are advantageous for research as the models are relatively straightforward to prepare and easily obtainable for research to perform surgical techniques. The intention of this study was to quantitatively analyze gene expression for collagen and proteoglycan components of the extracellular matrix and for collagenase (MMP-1) in porcine discs of varying ages (Newborn; 2-3weeks, Mature; 6-9 month, Older; 2-3 years). In this study, we observed that the cell number and GAG (glycosaminoglycan) formation dramatically decreased with aging. Also, gene expression in the annulus fibrosus (AF) and nucleus pulposus (NP) cells changed with aging. The level of MMP-1 mRNA increased with age and both type I, II collagens decreased with age. The level of aggrecan mRNA was highest in the mature group and decreased significantly with aging. In the mature group, MMP-1 expression was minimal compared to the newborn group. In AF cells, type II collagen was expressed at a high level in the mature group with a higher level of aggrecan, when aged NP showed a decrease in type II collagen. The model of IVD degeneration in the porcine disc shows many changes in gene expression with age that have been previously documented for human and may serve as a model for studying changes in IVD metabolism with age. We concluded that the porcine model is excellent to test hypotheses related to disc degeneration while permitting time-course study in biologically active systems.
Age Factors ; Aggrecans/genetics/metabolism ; Aging/genetics/*metabolism ; Animals ; Animals, Newborn ; Collagen Type I/genetics/metabolism ; Collagen Type II/genetics/metabolism ; Glycosaminoglycans/genetics/metabolism ; Humans ; Intervertebral Disk Degeneration/genetics/*metabolism ; Matrix Metalloproteinase 1/genetics/*metabolism ; *Models, Animal ; Reverse Transcriptase Polymerase Chain Reaction ; Spinal Cord/*metabolism/pathology ; Swine

Various tissues, including the heart, cornea, bone, esophagus, bladder and liver, have been vascularized using the cell sheet technique. It overcomes the limitations of existing techniques by allowing small layers of the cell sheet to generate capillaries on their own, and it can also be used to vascularize tissue-engineered transplants. Cell sheets eliminate the need for traditional tissue engineering procedures such as isolated cell injections and scaffold-based technologies, which have limited applicability. While cell sheet engineering can eliminate many of the drawbacks, there are still a few challenges that need to be addressed. The number of cell sheets that can be layered without triggering core ischemia or hypoxia is limited. Even when scaffold-based technologies are disregarded, strategies to tackle this problem remain a substantial impediment to the efficient regeneration of thick, living three-dimensional cell sheets. In this review, we summarize the cell sheet technology in myocardial infarcted tissue regeneration.

No abstract available.
Leukemia* ; Sweet Syndrome*

BACKGROUND: Eye irritation tests with animals have been conducted for a long time. However, the subjective decision to irritation, the anatomic/physiologic difference between species and humans, and ethical issues are crucial problems. Various research groups have paid attention to alternative testing methods. In these senses, we fabricated in vitro minicornea models with immortalized human corneal epithelial cells (iHCECs) and keratocytes (iHCKs) and used them for irritation tests. This study hypothesized that our mini-cornea model could present different viability tendencies according to test chemicals with different irritancy levels. METHODS: Cells used in this study were characterized with cornea-specific markers by immunocytochemistry and western blot. To make a three-dimensional hemisphere construct like cornea stroma, we cultured iHCKs under modified culture conditions verified by matrix formation and total collagen content. iHCECs were seeded on the construct and cultured at an air–liquid interface. The model was treated with 2-phenoxyethanol, triton X-100, sodium lauryl sulfate, and benzalkonium chloride. RESULTS: iHCECs and iHCKs presented their specific cell markers. In modifying the culture condition, the group treating ascorbic acid (200 lg/ml) presented an intact cellular matrix and included the highest collagen content; thus, we used this condition to fabricate the mini-cornea model. The model shows hemisphere shape and homogenous cell distributions in histological analysis. We observed different sensitivity tendencies by types of chemicals, and the model’s viability significantly decreased when the chemical concentration increased. CONCLUSION In this study, we performed and observed irritation tests using a tissue-engineered mini-cornea model and considered to apply as an alternative approach for animal tests.

Follicular dendritic cell (FDC) sarcoma is an extremely rare malignant neoplasm arising from FDCs. The exact origin of FDCs remains unclear; both a hematopoietic lineage origin and a stromal cell derivation have been proposed. Proliferation of FDCs can lead to benign reactive lesions or generate neoplastic conditions. The lesions are most commonly found in lymph nodes and usually involve the head and neck area. Castleman's disease is a rare non-neoplasitic lymphoproliferative disorder. Rare cases of hyaline-vascular Castleman's disease have been associated with FDC sarcoma, but a clonal relationship has not been convincingly demonstrated. A pathway toward tumor evolution, beginning with hyperplasia and dysplasia of FDCs, has been proposed. Despite this known association between Castleman's disease and FDC sarcoma, there have only been few reported cases of sarcoma arising as a complication of pre-existing Castleman's disease, especially in abdominal lesions. We describe here a 51-year-old female with an FDC sarcoma arising from unicentric, hyaline-vascular type Castleman's disease in an intra-abdominal mass. Pathologically, the lesion showed a series of changes during the process of transformation from Castleman's disease to FDC sarcoma.
Abdomen/ultrasonography ; Abdominal Neoplasms/*diagnosis/etiology/pathology ; Dendritic Cell Sarcoma, Follicular/*diagnosis/etiology/pathology ; Female ; Giant Lymph Node Hyperplasia/complications/*diagnosis ; Humans ; Middle Aged ; Positron-Emission Tomography ; Tomography, X-Ray Computed

Excessive exposure to several metallic elements is known to produce a variety of nephrotoxic syndromes such as glomerulonephritis, nephrotic syndrome, interstitial nephritis, structural and functional abnormalities of proximal tubule resembling the Fanconi's syndrome and acute tubular necrosis. Although the pulmonary toxicities of silicon are relatively well documented as a cause of silicoproteinosis and lung fibrosis after acute and chronic exposure to free silica(SiO2), but is little known about the nephrotoxicity of this trace element. Clinical manifestations of silicon nephropathy are similar to other heavy metal nephropathy as proteinuria, hematuria, active urinary sediments and renal failure. Diagnosis of silicon nephropathy is based on distinct exposure history to silica, variable degree of renal dysfunction and characteristic histologic findings such as cytoplasmic vacuoles and dense membrane-enclosed cytoplasmic bodies which is resembling lysosomes in proximal tubular cells. A 26-year-old man with ingestion of silicon compound(SiO2-NaOCO3) developed acute renal failure due to acute tubular necrosis. And he was recovered with conservative management to acute renal failure. So we report this case with a brief review of literature.
Acute Kidney Injury* ; Adult ; Cytoplasm ; Diagnosis ; Eating* ; Fibrosis ; Glomerulonephritis ; Hematuria ; Humans ; Lung ; Lysosomes ; Necrosis ; Nephritis, Interstitial ; Nephrotic Syndrome ; Proteinuria ; Renal Insufficiency ; Silicon Dioxide ; Silicon* ; Vacuoles