Prevention of liver fibrosis by intrasplenic injection of high-density cultured bone marrow cells in a rat chronic liver injury model.

Endothelial progenitor cells (EPCs) from bone marrow have proven to be functional for the prevention of liver fibrosis in chronic liver injury. However, expansion of EPCs in culture is complicated and expansive. Previously, we have established a simple method that could enrich and expand EPCs by simple seeding bone marrow cells in high density dots. The purpose of this study is to evaluate whether cells derived from high-density (HD) culture of rat bone marrow cells could prevent the liver fibrosis in a chronic liver injury rat model, induced by carbon tetrachloride (CCl4). Flow cytometric analysis showed that cells from HD culture were enriched for EPCs, expressing high levels of EPC markers. Intrasplenic injection of HD cultured bone marrow cells in the CCl4-induced liver injury rat showed an enhanced antifibrogenic effect compared with animals treated with cells from regular-density culture. The antifibrogenic effect was demonstrated by biochemical and histological analysis 4 weeks post-transplantation. Furthermore, cells from HD culture likely worked through increasing neovascularization, stimulating liver cell proliferation, and suppressing pro-fibrogenic factor expression. HD culture, which is a simple and cost-effective procedure, could potentially be used to expand bone marrow cells for the treatment of liver fibrosis.