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BACKGROUND: The construction of bioartificial liver is expected to be an effective method for the treatment of acute liver failure. However, there are still many problems in seed cell source, culture mode and nutrient acquisition, which restrict the development and clinical application of blood purification-artificial liver. OBJECTIVE: To investigate the feasibility of inducing the differentiation of induced pluripotent stem cells from human skin into hepatocyte-like cells without addition of exogenous sources such as exogenous serum. METHODS: A 3D culture system was constructed by using a three-dimensional culture system containing 6-well plates of the Transwell chamber. The induction and differentiation of human induced pluripotent stem cells were performed by addition of valproic acid and nicotinamide. The differentiated hepatocyte-like cells were co-cultured with biological patches. There were five groups in the experiment: human induced pluripotent stem cells were set as group A, normal hepatocytes as group B, hepatocyte-like cells without induction by nicotinamide as group C, hepatocyte-like cells with induction by nicotinamide as group D, and hepatocyte-like cells cultured on the biological patch as group E. The morphology of hepatocyte-like cells in group D was observed under inverted phase contrast microscope. The expression of nuclear factor 4α and alpha-fetoprotein in hepatocytes of group D was detected by immunofluorescence. Real-time quantitative PCR and western blot were used to detect mRNA and protein expressions of alpha-fetoprotein and albumin in the cells of groups A, B, C and D. Flow cytometry was used to detect the differentiation efficiency of cells in groups A, C and D. Immunocytochemistry detection was used to detect the protein expression of bile salt export pump in groups B and E. ELISA assay was used to detect lactate dehydrogenase activity, albumin and urea nitrogen contents in the supernatants of the groups D and E. RESULTS AND CONCLUSION: (1) The cells of group D changed from fusiform to polygon in shape. (2) Positive expression of hepatocyte nuclear factor 4 alpha and alpha fetoprotein was found in the cells of group D. (3) The gene and protein expressions of alpha fetoprotein and albumin in group D was significantly higher than those in groups A and C (P < 0.01). (4) The protein expression of bile salt export pump in the cells was remarkably positive in groups B and E. (4) The activity of lactate dehydrogenase and the contents of albumin and urea nitrogen in cultured cells of group E were significantly higher than those in group D (P < 0.01). To conclude, the combination of 3D culture system with exogenous small molecules and biological surgical patch helps to induce induced pluripotent stem cells to differentiate into functional hepatocyte-like cells in vitro. [ABSTRACT FROM AUTHOR]

BACKGROUND: Whether controlling of post-injury inflammatory response combined with neural stem cell (NSC) transplantation can improve the curative efficacy for spinal cord injury still remains unclear. OBJECTIVE: To investigate the repair of spinal cord tissue, myelin regeneration, axon regeneration, motor function recovery and the possible mechanism after early application of tumor necrosis factor α antagonist (Etanercept) combined with tyrosine kinase C (TrkC) gene-modified NSC transplantation. METHODS: TrkC-overexpressed NSCs (TrkC-NSCs) were constructed by lentiviral transfection technique. The rat models of spinal cord transection injury were prepared, and then subjected to Etanercept combined with TrkC-NSCs transplantation. The number of neurons and neuroregeneration after injury were measured by Nissl's staining, immunofluorescence and western blot. The rat motor function was detected by Basso Beattie Bresnahan score and evoked potential. The myelin regeneration was detected by electron microscopy and toluidine blue staining. RESULTS AND CONCLUSION: Compared with the other groups, the Etanercept combined with TrkC-NSCs transplantation group had more survived anterior horn motor neurons at 28 days after injury, more myelin-encapsulated axons, higher Basso Beattie Bresnahan score, greater amplitude of the evoked potentials, and relatively shorter latency (all P < 0.05). These findings indicate that early application of tumor necrosis factor-α antagonist combined with TrkC-NSCs transplantation after spinal cord injury in rats can effectively promote myelin regeneration, axon regeneration, and further promote motor function recovery. [ABSTRACT FROM AUTHOR]