Design and fabrication of an integrated 3D dynamic multicellular liver-on-a-chip and its application in hepatotoxicity screening.

Nowadays, major methods of in vitro hepatotoxicity research are still based on traditional static two- or three-dimensional cell culture, although these means could investigate some toxic chemicals induced hepatotoxicity, but most of these toxicities failed to reappear in human, at least not in similar or calculable dose level. These failures may cause by the monoculture of only hepatocytes, ignored the signal communication to other non-parenchymal cells in liver tissue, also other complex microenvironment such as endothelial barrier, shear stress and other factors which were really existed in vivo but absent here, final leading to a low reliability of experimental results. In this study, a three-dimensional dynamic multi-cellular liver-on-a-chip device (3D-DMLoC) was developed to reproduce the microenvironment of in vivo liver tissue, including the simulation of hepatic sinusoid, perisinusoidal space and continuous liquid perfusion, hepatocytes could gather to some 3D cell spheroids in this chip. The perfusion could bring a real-time exchange of chemicals, nutrients, metabolites, supply suitable oxygen and a weak shear stress. The pressure and oxygen distribution inner the chip were simulated and evaluated by COMSOL Multiphysics software. HepaRG were co-cultured with HUVEC for 7 days in this chip, expression of hepatic polarization protein ZO-1 and MRP2, liver function factors ALB, UREA and CYP450s were almost all higher than in traditional static culture. Several drugs and heavy metal ions induced hepatotoxicity were then investigated, LDH released from hepatocyte spheroids in mostly 3D-DMLoC groups were higher than same-dosed 2D group, indicated the spheroids were more sensibility to the toxins. The hepatoxicity might be induced by acute hepatocytes injury according to the ratios of secreted AST/ALT contents. In conclusion, a liver-on-a-chip device was successfully developed and verified for better reproducing the in vivo physiological microenvironment of liver. It could be applied for easily, efficiently, and accurately screening the potential hepatotoxic chemicals in future.

Lower circulating preptin levels in male patients with osteoporosis are correlated with bone mineral density and bone formation.

BACKGROUND: Serum preptin levels among subjects with different bone mineral densities (BMD) were measured and investigated to determine the correlation between BMD and bone-metabolic markers. METHODS: Approximately 52 elderly male patients with osteoporosis, 50 elderly men with osteopaenia, and 31 age-matched normal bone mass controls participated in the study. The serum preptin levels and bone metabolic markers were measured by enzyme-linked immunosorbent assay. The relationships between preptin levels, BMD, and metabolic parameters were also assessed. RESULTS: The serum preptin level was the lowest in the osteoporosis group and positively correlated with BMD. All the bone formation markers in the osteoporosis and osteopaenia groups were significantly reduced compared with those in the normal group. Serum preptin level was positively correlated with all the bone formation markers, whereas no correlation was observed with the bone resorption marker TRACP-5b. CONCLUSIONS: Serum preptin levels are decreased in osteoporosis and osteopaenia patients and positively correlated with BMD. Therefore, preptin is involved in the pathogenesis of osteoporosis, probably through bone formation rather than bone resorption.

[Photoelectron time-resolved spectrum and phosphor spectrum of luminescent material ZnO by microwave absorption method].

The process of decay of photo-generated electrons in the conduction band of ZnO:Zn and ZnO powder materials after excitation with a ultra-short pulse laser has been investigated in this paper by microwave absorption method. The excitation and emission spectra of ZnO:Zn were measured at room temperature. It was measured that the lifetime o photoelectrons in the materials ZnOand ZnO:Zn are 64 ns and 336 ns respectively. It is believed that the increase of the lifetime in the material of ZnO:Zn is due to the prolong of relaxation time caused by the defect structure in the material.