Correction of copper metabolism is not sustained long term in Wilson’s disease mice post bone marrow transplantation

Abstract

Alternative cell sources have been sought for the treatment of liver diseases, since liver cells are in short supply for cell transplantation. Although bone marrow-derived cells have been investigated as an alternative cell source, few studies have demonstrated long-term disease correction. Here we examined bone marrow stem cell transplantation into the toxic milk (tx) mouse model for Wilson's disease, a mild liver disease characterized by hepatic copper accumulation. The aim of this study was to determine whether bone marrow cells engrafted in the liver could sustain correction of abnormal copper metabolism in the tx mouse. Bone marrow cells were isolated from congenic normal mice, transduced to express enhanced green fluorescent protein, sorted for stem cell (Sca-1) and lineage cell (Lin) surface markers, and then transplanted into sub-lethally irradiated normal or tx mice. Analysis for donor cell activity and distribution was undertaken 5 and 9 months post-transplant to allow for sufficient time to repopulate the liver and demonstrate disease correction. Donor bone marrow cells engrafted in both normal and tx mouse liver within 5 months. Significantly reduced liver copper was found in tx mice with donor cell liver engraftment at 5 months post-transplant compared to controls, demonstrating partial correction of abnormal copper metabolism in the short term. However, disease correction was not maintained 9 months post-transplantation. Lin(-)Sca-1(+) cells were more likely to partially correct disease than Lin(+)Sca-1(-) cells in the short term. These results demonstrate that bone marrow transplants cannot maintain disease correction in a mouse model of mild hepatic damage, although initial copper metabolism correction was observed.