Publications by authors named "Hee-Hoon Yoon"

The bioartificial liver (BAL) system can potentially rescue acute liver failure (ALF) patients by providing partial liver function until a suitable donor liver can be found or the native liver has self-regenerated. In this study, we established a suitable cryopreservation process for the development of an off-the-shelf BAL system. The viability of hepatocyte spheroids cryopreserved in liquid nitrogen was comparable to that of fresh primary hepatocyte spheroids.

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Article Synopsis
  • * The new serum-free cryopreservation solutions showed improved cell viability and liver function markers (like ammonia removal and albumin synthesis) in hepatocyte spheroids compared to those using serum.
  • * The cryopreserved spheroid-based bioartificial liver system demonstrated comparable performance to fresh systems in ammonia removal and urea production, making it a promising option for patient treatment.
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Bioartificial livers (BAL) may offer acute liver failure (ALF) patients an opportunity for cure without liver transplantation. We evaluated the efficacy of a spheroid-based BAL system, containing aggregates of porcine hepatocytes, in a porcine model of ALF. ALF pigs were divided into three groups.

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Biophysical wave stimulus has been used as an effective tool to promote cellular maturation and differentiation in the construction of engineered tissue. Pulsed electromagnetic fields (PEMFs) and sound waves have been selected as effective stimuli that can promote neural differentiation. The aim of this study was to investigate the synergistic effect of PEMFs and sound waves on the neural differentiation potential in vitro and in vivo using human bone marrow mesenchymal stem cells (hBM-MSCs).

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Various animal models of stroke have been developed to simulate the human stroke with the development of the ischemic method facilitates preclinical stroke research. The photothrombotic ischemia model, based on the intravascular photochemical reaction, is widely used for in vivo studies. However, this study has limitations, which generated a relatively small-sized infarction model on superficial cortex compared to that of the MCAO stroke model.

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Effects of mechanical vibration on cell activity and behavior remain controversial: There has been evidence on both positive and negative effects. Furthermore, research on the anterior cruciate ligament (ACL) has as yet been limited and the frequency-related effects remain unknown, even though ACL injury is common and an injured ACL hardly spontaneously recovers. The object of this work was to address the influence of mechanical vibration on ACL fibroblasts, to determine the effects of frequencies, and to further study this effect at the cellular level.

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Even though the inducing effect of electromagnetic fields (EMF) on the neural differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) is a distinctive, the underlying mechanism of differentiation remains unclear. To find out the signaling pathways involved in the neural differentiation of BM-MSCs by EMF, we examined the CREB phosphorylation and Akt or ERK activation as an upstream of CREB. In hBM-MSCs treated with ELF-EMF (50 Hz, 1 mT), the expression of neural markers such as NF-L, MAP2, and NeuroD1 increased at 6 days and phosphorylation of Akt and CREB but not ERK increased at 90 min in BM-MSCs.

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Aims: Adipose tissue-derived stem cells (AT-MSCs) have been proposed as a new source for nervous tissue damage due to their capacity of neural differentiation potential including neurons, oligodendrocytes and astrocytes. Recently, many studies have demonstrated that sub-sonic vibration (SSV) is an effective cell differentiation method but there have been no studies on the effect of SSV about AT-MSC differentiation into neural-like cells in vitro. Therefore, we examined the effect of SSV on AT-MSCs to investigate the differentiation potential of neural-like cells.

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Adult stem cells are considered multipotent. Especially, human bone marrow-derived mesenchymal stem cells (hBM-MSCs) have the potential to differentiate into nerve type cells. Electromagnetic fields (EMFs) are widely distributed in the environment, and recently there have been many reports on the biological effects of EMFs.

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Aims: Adult stem cells, such as umbilical cord-derived mesenchymal stem cells (UC-MSCs), have the potential to differentiate into various types of cells, including neurons. Research has shown that mechanical stimulation induces a response in MSCs, specifically, low and high intensity sub-sonic vibration (SSV) has been shown to facilitate wound healing. In this study, the effects of SSV were examined by assessing the proliferation and differentiation properties of MSCs.

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In this study, we evaluated the effect of mechanical stimulation on the differentiation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) in osteogenic medium using a Flexcell system that imposed cyclic uniaxial mechanical stimulation at a strain of 0%, 5%, or 10% (5 s of stretch and 15 s of relaxation) for 10 days. The expression of MSC surface antigens (CD73, CD90, and CD105) was significantly decreased as strain increased. Mechanical stimulation inhibited the growth of UC-MSCs and slightly raised lactate dehydrogenase production.

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Aims: Although low and high intensity sub-sonic vibrations (SSV) have been shown to facilitate wound healing, very few studies have investigated the effects of SSV on 3T3-L1 preadipocytes. Therefore, the present study was undertaken to investigate the influence of SSV on the proliferation and maturation of 3T3-L1 preadipocytes.

Main Methods: To evaluate the effect of SSV on 3T3-L1 cell proliferation, the cells were maintained in an apparatus that administered SSV (0.

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Background: The methods currently used for treating alopecia have some limitations. The drug treatment is so temporary that medication discontinuance may progress depilation immediately. The number of hair transplantation restricts because total transplantable hair number is no increase.

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The purpose of this study was to evaluate the biocompatibility of silk and collagen-hyaluronan (HA) in vitro by assessing anterior cruciate ligament (ACL) cell and T-lymphocyte cultures on scaffolds. The use of composite scaffolds as artificial ligaments in ACL reconstruction and their effects on angiogenesis were evaluated in vivo. The silk scaffold was knitted by hand and dry coated with collagen-HA, whereas the composite silk scaffold was made by covering a silk scaffold with a lyophilized collagen-HA substrate.

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Umbilical cord blood (UCB) is a rich source of hematopoietic stem cells that possesses practical and ethical advantages. We previously reported a novel UCB-derived adult stem cells which we termed umbilical cord blood-derived multipotent progenitor cells' (MPCs). MPCs were capable of differentiating into functional neuronal cells.

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Mesenchymal stem cells (MSCs) derived from bone marrow are an important tool in tissue engineering and cell-based therapies because of their multipotent capacity. Majority of studies on MSCs have investigated the roles of growth factors, cytokines, and hormones. Antioxidants such as ascorbic acid can be used to expand MSCs while preserving their differentiation ability.

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Glycogen storage disease type I (GSD-I) is a group of autosomal recessive disorders with an incidence of 1 in 100,000. The two major subtypes are GSD-Ia, caused by a deficiency of glucose-6-phosphatase (G6Pase), and GSD-Ib, caused by a deficiency of glucose-6-phosphate transporter (G6PT). We report that a substantial improvement was achieved following several infusions of hepatocytes in a patient with GSD-Ib.

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Rabbit corneal epithelium was reconstructed using tilting dynamic culture with a self-manufactured, amniotic membrane (AM) supporter and a lyophilized amniotic membrane (LAM). Rabbit corneal epithelial (RCE) cells were cultured and cryopreserved after isolation from the limbus. The second- and third-passage RCE cells were plated onto the epithelial side of the LAM of Ahn's AM supporter.

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