No abstract

IntroductionAcute liver failure (ALF) is a highly lethal disease, for which effective therapeutic methods are limited. Although allogeneic liver transplantation is a viable treatment method for ALF, there is a serious shortage of liver donors. Recent studies suggest that stem cell transplantation is a more promising alternative. Hence, we investigate whether human adipose-derived stem cells (ASCs) have the therapeutic potential for ALF in this study based on the studies of rat models.MethodsSprague Dawley rats were used to establish ALF models by D-galactosamine injection. These rats were randomly divided into a human ASC-treated group and a phosphate-buffered saline (PBS) control group. The human ASCs or PBS was transplanted through the spleen of rats. The indices of hepatic function and hepatic histology were dynamically detected, and the survival rates of rats were also counted. Double-fluorescence immunohistochemistry was employed to detect the ASC fate after transplantation. Moreover, both concentrated ASC conditional media and ASC lysates were transplanted through the femoral vain of rats to investigate the therapeutic potential for ALF.ResultsThe ASC transplantation group showed improved viability in comparison with the sham control. Histological and biochemical analysis suggested that liver morphology and function were improved in terms of cell proliferation and apoptosis. Although a plethora of ASCs persist in the spleen, the improvement in liver function was obvious. However, ASCs did not differentiate into hepatocytes after engrafting to livers within 3 days. In addition, both concentrated serum-free ASC conditional media and ASC lysates, characterized by high levels of hepatocyte growth factor and vascular endothelial growth factor, demonstrated obvious improvement in terms of high survival rates of ALF rats.ConclusionOur data suggest that ASC transplantation has the potential for ALF treatment partly by the mechanism of secreting growth factors contributing to liver regeneration.

Abstract:The summer maize yields and partial factor productivity of nitrogen (N) fertilizer (PFP N , grain yield per unit N fertilizer) on smallholder farms in China are low, and differ between farms due to complex, sub-optimal management practices. We collected data on management practices and yields from smallholder farms in three major summer maize-producing sites-Laoling, Quzhou and Xushui-in the North China Plain (NCP) for two growing seasons, during 2015-2016. Boundary line analysis and a Proc Mixed Model were used to evaluate the contribution of individual factors and their interactions. Summer maize grain yields and PFP N ranged from 6.6 t ha −1 to 14.2 t ha −1 and 15.4 kg kg −1 to 96.1 kg kg −1 , respectively, and averaged 10.5 t ha −1 and 49.1 kg kg −1 , respectively. The mean total yield gap and PFP N gap were 3.6 t ha −1 and 43.3 kg kg −1 in Laoling, 2.2 t ha −1 and 24.5 kg kg −1 in Xushui, and 2.8 t ha −1 and 41.1 kg kg −1 in Quzhou. A positive correlation was observed between the yield gap and PFP N gap; the PFP N gap could be reduced by 6.0 kg kg −1 (3.6-6.6 kg kg −1 ) by reducing the yield gap by 1 t ha −1 . The high yield and high PFP N (HH) fields had a higher plant density and lower N fertilization rate than the low yield and low PFP N (LL) fields. Our results show that multiple management factors caused the yield gap, but the relative contribution of plant density is slightly higher than that of other management practices, such as N input, the sowing date, and potassium fertilizer input. The low PFP N was mainly attributed to an over-application of N fertilizer. To enhance the sustainable production of summer maize, the production gaps should be tackled through programs that guide smallholder farmers on the adoption of optimal management practices.