**Acknowledgements**

In this sense, human liver segments proceeding from surgical resection in patients with cancer were injected with different genes to evaluate the potential transferability of this technique. Given their precedence, the vasculature of these human liver segments is entirely excluded so they are watertight and hence, pressurized. The gene is retrogradely transfected through a catheter placed in a hepatic vein (**Figure 7**) and the segment remains watertight for 5 min. The first studies of gene transfer with human liver segments [56] used the eGFP tracer gene in order to easily determine its expression efficacy, and it was demonstrated that the gene could be efficiently delivered and the protein was produced within the liver tissue as observed by fluorescence microscopy. After confirming the feasibility of the technique in this type of tissue, genes with clinical interest were employed to define the translational potential to clinical real settings. Sendra Gisbert et al. [55] transferred a plasmid bearing the human interleukin-10 gene (IL10). Interleukin-10 is an immunomodulatory protein with pleotropic effects with potential interest for the treatment of inflammatory diseases or for inducing tolerance in organ transplantation. The rate of tissue protein translation achieved was around 1000 copies per cell, this meaning the potential therapeutic production of protein (IC50 of IL10 for TNFa = 124 pg) if

Our group also transferred in similar human liver segments a plasmid with the same human alpha-1-antitrypsin employed in mice and pigs but modified. In order to permit differing endogenous and exogenous genes and proteins, a sequence of nucleotides encoding the flag peptide was added. Preliminary experiments demonstrate that the procedure is efficient and the use of a human gene in human tissue favors the production of protein. First, results

–105

The efficacy of gene transfer can be measured by different techniques and authors have studied many variables to present their results and evaluate how efficient a procedure is. This requires the use of a more detailed analysis that allows to identify the effectiveness of each of the stages of the process of delivery of the gene, its decoding of protein and its subsequent location.

**Figure 7.** Catheterization of human liver segment. Left panel shows a schematic figure of a human liver segment with a catheter placed in a hepatic vein. Right panel is a radiographic image of a human liver segment injected with iodinated

accounting for up to 22% of all the hAAT proteins present in the liver tissue in 1 week.

copies of hAAT-flag protein per cell, this

compared with other results of the same group.

194 Liver Research and Clinical Management

prove a rate of tissue protein translation of 104

contrast solution through hepatic vein. Modified from [55].

This work has been partially supported by Spanish Ministerio de Economía y Competitividad (SAF2011-27002, SAF2007-64492) and Grifols ALTA Award 2017.
