3D Particle Simulation of Liver Cell Proliferation with Angiogenesis - Partial Hepatic Lobule Formation-

Recently, the prevalence of viral hepatitis patients has been increasing. Therefore, the reconstruction of liver based on tissue engineering has attracted significant attention. However, the formation or regeneration mechanisms of the liver have not been elucidated; therefore, practical regenerative medicine technology based on tissue engineered liver has not been accomplished. In this study, we propose an analysis model using a Particle Model as the first step. The analysis object is a hepatic lobule. The purpose of this analysis is to elucidate the process of cell proliferation, mechanisms, and states at the micro scale. We used parameters which were obtained by experiments using rats relating to diffusivity, oxygen concentration, and oxygen consumption of a cell. Moreover, we used complex velocity potential of fluid dynamics and obtained a result corresponding to a real hepatic lobule, qualitatively.The 6th TSME International Conference on Mechanical Engineering, 16-18 December 2015, at The Regent Cha-am beach Resort, Hua-Hin, Thailand

3D Particle Simulation of Liver Cell Proliferation with Angiogenesis - Partial Hepatic Lobule Formation-

The 6th TSME International Conference on Mechanical Engineering, 16-18 December 2015, at The Regent Cha-am beach Resort, Hua-Hin, Thailand.Recently, the prevalence of viral hepatitis patients has been increasing. Therefore, the reconstruction of liver based on tissue engineering has attracted significant attention. However, the formation or regeneration mechanisms of the liver have not been elucidated; therefore, practical regenerative medicine technology based on tissue engineered liver has not been accomplished. In this study, we propose an analysis model using a Particle Model as the first step. The analysis object is a hepatic lobule. The purpose of this analysis is to elucidate the process of cell proliferation, mechanisms, and states at the micro scale. We used parameters which were obtained by experiments using rats relating to diffusivity, oxygen concentration, and oxygen consumption of a cell. Moreover, we used complex velocity potential of fluid dynamics and obtained a result corresponding to a real hepatic lobule, qualitatively

2D Particle Simulation of Liver Cell Proliferation with Angiogenesis - Hepatic Lobule Formation

The liver has the ability to reform and regenerate in our body. However, the mechanisms of reformation or regeneration of the liver have not been elucidated. In this study, we propose an analysis model using a Particle Model to elucidate the mechanism of liver formation. The object of analysis is a hepatic lobule, which is the basic component of the liver. First, a 2-dimensional cell proliferation around one blood vessel was modeled. Second, angiogenesis was added and considered. And finally, the model was applied to the hepatic lobule and the 2D formation of the hepatic lobule was revealed. We used experimentally derived parameters such as diffusivity, oxygen concentration, and oxygen consumption of a cell. The model will be expected to facilitate in developing tissue-engineered liver using regenerative medicine technology.2nd Conference on Advances in Prevention and Treatment of Cancer (CAPTC 2016), March 18-20, 2016, Los Angeles, US

Particle Simulation of Liver Cell Proliferation with Angiogenesis -Whole Hepatic Lobule Formation-

The liver is the organ primarily responsible for our metabolism and loss of its function　generally results in death.　Luckily, the liver has a high regenerative ability. However, the mechanism of its regeneration has not yet been　clarified. This study therefore models liver　regeneration via a numerical simulation. In　addition, this simulation may　aid other experiments in the field of regenerative　medicine. As a first step, this study proposes an analytical model　based on the particle method. The analysis object is a hepatic lobule. The purpose of this analysis is to elucidate the　process, mechanism, and condition of cell growth on the micro-scale. Experiments using rats were conducted to　obtain the parameters for the model, namely the diffusivity, oxygen concentration, and oxygen consumption rate of a cell. The most difficult to solve problem in liver cell proliferation technology is the　restricted volume in which　cells survive owing to oxygen supply problems. It is therefore necessary to extend the cell survival volume by　angiogenesis. Here, results were generated using a model of angiogenesis in which blood vessels formed from the　portal veins to a central vein, with repeated branching and connecting across the whole of the liver. In this way a　hepatic lobule was filled with liver cells. Additionally, the analysis results yielded the rates of the cross sectional　areas of the blood vessels. This research further aims to analyze the macro region by using analysis results obtained　on the micro-scale. Applying the thresholds which is the most closed to the experimental value obtained from　analysis results on the micro-scale to the macro region, it becomes available to curtail expenses and be kind to　animals in the liver experiments.The 7th International Conference on Mechanical Engineering (TSME-ICoME 2016), 13-16 December 2016, Chiang Mai, Thailand

Analysis of Sulfated Glycosaminoglycans in ECM Scaffolds for Tissue Engineering Applications: Modified Alcian Blue Method Development and Validation

Accurate determination of the amount of glycosaminoglycans (GAGs) in a complex mixture of extracellular matrix (ECM) is important for tissue morphogenesis and homeostasis. The aim of the present study was to investigate an accurate, simple and sensitive alcian blue (AB) method for quantifying heparin in biological samples. A method for analyzing heparin was developed and parameters such as volume, precipitation time, solvent component, and solubility time were evaluated. The AB dye and heparin samples were allowed to react at 4 ℃ for 24 h. The heparin-AB complex was dissolved in 25 N NaOH and 2-Aminoethanol (1:24 v/v). The optical density of the solution was analyzed by UV-Vis spectrometry at 620 nm. The modified AB method was validated in accordance with U.S. Food and Drug Administration guidelines. The limit of detection was found to be 2.95 µg/mL. Intraday and interday precision ranged between 2.14−4.83% and 3.16−7.02% (n = 9), respectively. Overall recovery for three concentration levels varied between 97 ± 3.5%, confirming good accuracy. In addition, this study has discovered the interdisciplinary nature of protein detection using the AB method. The basis for this investigation was that the fibrous protein inhibits heparin-AB complex whereas globular protein does not. Further, we measured the content of sulfated GAGs (sGAGs; expressed as heparin equivalent) in the ECM of decellularized porcine liver. In conclusion, the AB method may be used for the quantitative analysis of heparin in ECM scaffolds for tissue engineering applications

Physical Properties of the Extracellular Matrix of Decellularized Porcine Liver

The decellularization of organs has attracted attention as a new functional methodology for regenerative medicine based on tissue engineering. In previous work we developed an L-ECM (Extracellular Matrix) as a substrate-solubilized decellularized liver and demonstrated its effectiveness as a substrate for culturing and transplantation. Importantly, the physical properties of the substrate constitute important factors that control cell behavior. In this study, we aimed to quantify the physical properties of L-ECM and L-ECM gels. L-ECM was prepared as a liver-specific matrix substrate from solubilized decellularized porcine liver. In comparison to type I collagen, L-ECM yielded a lower elasticity and exhibited an abrupt decrease in its elastic modulus at 37 °C. Its elastic modulus increased at increased temperatures, and the storage elastic modulus value never fell below the loss modulus value. An increase in the gel concentration of L-ECM resulted in a decrease in the biodegradation rate and in an increase in mechanical strength. The reported properties of L-ECM gel (10 mg/mL) were equivalent to those of collagen gel (3 mg/mL), which is commonly used in regenerative medicine and gel cultures. Based on reported findings, the physical properties of the novel functional substrate for culturing and regenerative medicine L-ECM were quantified