In Vitro Evaluation of Cytotoxicity and Proliferative Effects of Lyophilized Porcine Liver Tissue on HepG2 Hepatoma Cells and Adipose-Tissue-Derived Mesenchymal Stromal Cells

Abstract

In recent years, nutritional supplements from different sources have been widely considered to support medical treatments in patients affected by chronic hepatopathies. Their potential therapeutic benefit has been recognized, but some evidence of safety issues has been reported. Recently it has been hypothesized that the liver could produce various of bioactive factors to maintain organ homeostasis and promote tissue healing. Thus, liver-specific preparations containing bioactive factors could provide a suitable substrate for in vitro study of liver tissue maintenance/healing, as a prospective regenerative medicine approach. Furthermore, they could represent a dietary supplement or nutraceutical for adjuvant therapies when correctly prepared and formulated. This work aims to provide data about the safety and biological activity of a freeze-dried porcine liver preparation. The lyophilized powder obtained from the whole organ has been tested in term of in vitro cell cytotoxicity (MTT assay) and proliferation assays (bromo-deoxyuridine incorporation and direct cell count) in two different cell types: human hepatoma HepG2 cell line and adipose-tissue-derived canine mesenchymal stromal cells (At-MSCs). At concentration levels between 100 to 500 µg/mL, the lyophilized liver powder stimulated mitochondrial metabolism as assessed by MTT assay (p ≤ 0.001 for HepG2 and for At-MSCs) and induced an increase in bromo-deoxyuridine incorporation in both cell types (p ≤ 0.01 for HepG2 and p < 0.001 for At-MSCs). In addition, direct cell count demonstrated a higher proliferative activity in treated At-MSCs (p < 0.001). Although preliminary, these data suggest that the whole-liver powder is noncytotoxic in vitro and may represent a stimulus to cell metabolism and proliferation. Further studies are needed to detect the bioactive components of the supplement and characterize in deeper detail the cellular pathways that they can modulate.