**5. Conclusion**

170 Liver Regeneration

origin (CD133 positive cells) applied after PVE in human surgery can increase the FLRV (Furst, 2007). From the present experimental data, however, it cannot be concluded with certainty that the application of stem cells, including MSC, does not support the growth of liver malignancies to the same extent that it supports liver regeneration. Assuming a bystander effect of MSC on the micromilieu makes this even more likely (Alison, 2006). Thus, further animal investigation is necessary before optimized MSC therapies can be applied in the setting of human medicine (Alison, 2006). In conclusion, it has been hereby shown that the intraportal infusion of syngeneic porcine MSC after PVE in a setting of liver regeneration led to an accelerated and augmented compensatory liver hypertrophy. This effect is most likely due to

The increased number of larger lobulus in the hypertrophic parenchyma of TNF-α group in comparison with control group could be explained by incomplete liver regeneration. Because there are practically no mitotic figures or the amount is of same quantity as in the normal liver parenchyma without any surgical procedures or toxic insult, we could hypothesize, that the first phase of liver regeneration is finished and the next phase of regeneration proceeds. It means the remodelation phase and the phase, when the liver microstructure is restored. Next would be objective to future study – the detection of intracellular or extracelular matrix changes during the process of liver regeneration. No differences in the amount of binucleated hepatocytes could be discussed also by end of proliferative phase of liver parenchyma at the time of sampling. The same size of hepatocytes and no atypical hepatocytes in the biopsies could also be explained by the same reason. This hypothesis is supported by restitution of all liver function monitored by biochemical parametres at the moment of sacrifying of experimental animals (Liska, 2012). The increased number of binucleated hepatocytes in the hypertrophic parenchyma of IL-6 group in comparison with control group could be explained by incomplete liver regeneration at the end of experiment. Because there are practically no mitotic figures or the amount is of same quantity as in the normal liver parenchyma without any surgical procedures or toxic insult, we could hypothesize, that the first phase of liver regeneration is finished and the next phase of regeneration proceeds. It means the remodelation phase and the phase, when the liver microstructure is restored. Next would be objective to future study – the detection of intracellular or extracellular (matrix) changes during the process of liver regeneration. No significant differences in other histological parameters (diameter of

The larger distribution of the number of binucleated hepatocytes in the hypertrophic parenchyma of TGF-β1 group in comparison with the control group could be explained by incomplete liver regeneration at the end of experiment. Because there are practically no mitotic figures, or the amount is the same as in the normal liver parenchyma without any surgical procedures or toxic insult, it was possible to hypothesize that the first phase of liver regeneration was finished and the next phase of regeneration was proceeding, namely the remodelling phase and the phase when the liver microstructure is restored (Mangnall, 2003). The size of hepatocytes and the length of lobuli were not proved to be statistically different between study and control group. The same size of hepatocytes and length of lobuli in the bioptical samples from the hypertrophic parenchyma could be also explained in the same way. This hypothesis is supported by the restitution of all liver functions monitored by biochemical parameters and completion of the proliferative phase of liver regeneration at the moment of

bystander effects of the transplanted MSC (Liska, 2009).

lobulus and hepatocytes) were not proved (Liska, 2009).

sacrificing of the experimental animals (Liska, 2012).

Application of IL-6 and TNF-α augments hypertrophy of FLRV on 7th postoperative day in comparison to control group. In case of application of MAB TGF-β1 we observed maximal increase of FLRV between 3rd and 7th days. Application of MSC augments hypetrophy of FLRV on 3rd day. The biochemical and histological examinations did not prove any important differencies among the groups. The use of TNF-α, IL-6, MAB TGF-β1, MSC could increase the process of liver regeneration after portal vein ligation.These experimental results could be used in clinical practice in patients with risk of acute liver failure after extended liver resection.
