Reconstruction of liver organoid using a bioreactor

AIM： To develop the effective technology for reconstruction of a liver organ in vitro using a bio-artificial liver. METHODS： We previously reported that a radial-flow bioreactor （RFB） could provide a three-dimensional highdensity culture system. We presently reconstructed the liver organoid using a functional human hepatocellular carcinoma cell line （FLC-5） as hepatocytes together with mouse immortalized sinusoidal endothelial cell （SEC） line M1 and mouse immortalized hepatic stellate cell （HSC） line A7 as non parenchymal cells in the RFB. Two × 10^7 FLC-5 cells were incubated in the RFB. After 5 d, 2 × 10^7 A7 cells were added in a similar manner followed by another addition of 10^7 M1 cells 5 d later. After three days of perfusion, some cellulose beads with the adherent cells were harvested. The last incubation period included perfusion with 200 nmol/L swinholide A for 2 h and then the remaining cellulose beads along with adherent cells were harvested from the RFB. The cell morphology was observed by transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. To assess hepatocyte function, we compared mRNA expression for urea cycle enzymes as well as albumin synthesis by FLC-5 in monolayer cultures compared to those of single-type cultures and cocultures in the RFB. RESULTS： By transmission electron microscopy, FLC-5, M1, and A7 were arranged in relation to the perfusion side in a liver-like organization. Structures resembling bile canaliculi were seen between FCL-5 cells. Scanning electron microscopy demonstrated fenestrae on SEC surfaces. The number of vesiculo-vacuolar organelles （WO） and fenestrae increased when we introduced the actin-binding agent swinholide-A in the RFB for 2h. With respect to liver function, urea was found in the medium, and expression of mRNAs encoding arginosuccinate synthetase and arginase increased when the three cell types were cocultured in the RFB. However, albumin synthesis decreased. CONCLUSION： Co-culture in the RFB system can dramatically change the structure and function of all cell types, including the functional characteristics of hepatocytes. Our system proves effective for reconstruction of a liver organoid using a bio-artificial liver.

The Planning, Organization and Management of Post-disaster Reconstruction of the Lushan Earthquake Based on the Local as the Main Body

A new organization and management mechanism with the local government as the main body was created during the post-disaster reconstruction of the "4. 20 " Lushan earthquake,in which the experiences and lessons were drawn from the "5. 12"Wenchuan earthquake. Correspondingly, the local government conducted an exploration of the organization and management mode in the field of planning and construction. The effective experiences have been accumulated, including working out a full coverage planning,taking the leading part in the urban-rural planning,and exercising whole space control over the disaster area. An innovation management mode named as "Five Generals Pattern"was implemented in the construction projects. In view that the rural housing reconstruction was a weak link, a new approach to improving the construction management was investigated,by means of strengthening on-site supervision,establishing a technical platform,and bolstering public participation.

Xenogeneic stem cell transplantation:Research progress and clinical prospects

Organ transplantation is the ultimate treatment for end-stage diseases such as heart and liver failure.However,the severe shortage of donor organs has limited the organ transplantation progress.Xenogeneic stem cell transplantation provides a new strategy to solve this problem.Researchers have shown that xenogeneic stem cell transplantation has significant therapeutic effects and broad application prospects in treating liver failure,myocardial infarction,advanced type 1 diabetes mellitus,myelosuppression,and other end-stage diseases by replacing the dysfunctional cells directly or improving the endogenous regenerative milieu.In this review,the sources,problems and solutions,and potential clinical applications of xenogeneic stem cell transplantation will be discussed.

Bioscaffolds embedded with regulatory modules for cell growth and tissue formation:A review

The demand for artificial organs has greatly increased because of various aging-associated diseases and the wide need for organ transplants.A recent trend in tissue engineering is the precise reconstruction of tissues by the growth of cells adhering to bioscaffolds,which are three-dimensional(3D)structures that guide tissue and organ formation.Bioscaffolds used to fabricate bionic tissues should be able to not only guide cell growth but also regulate cell behaviors.Common regulation methods include biophysical and biochemical stimulations.Biophysical stimulation cues include matrix hardness,external stress and strain,surface topology,and electromagnetic field and concentration,whereas biochemical stimulation cues include growth factors,proteins,kinases,and magnetic nanoparticles.This review discusses bioink preparation,3D bioprinting(including extrusion-based,inkjet,and ultraviolet-assisted 3D bioprinting),and regulation of cell behaviors.In particular,it provides an overview of state-of-the-art methods and devices for regulating cell growth and tissue formation and the effects of biophysical and biochemical stimulations on cell behaviors.In addition,the fabrication of bioscaffolds embedded with regulatory modules for biomimetic tissue preparation is explained.Finally,challenges in cell growth regulation and future research directions are presented.