Improved adhesion of Adult-derived human liver stem cells (ADHLSCs) to endothelial cells by culture on thermosensitive polymer

ADHLSC infusions are undergoing clinical trials. As many MSCs, they are both facing low engraftment levels. MSCs appear to use a mechanism of rolling and firm adhesion similar to leukocytes to engraft in organs. They mainly use the couple of integrins VLA-4 to bind VCAM-1 on the endothelium and transmigrate as they do not express the other molecules involved in the process. Unfortunately, ADHLSCs express VLA-4 to a slight degree. Here we investigated the benefit of using alternative methods to culture and harvest ADHLSCs in order to avoid trypsinization. ADHLSC were cultured on a thermosensitive polymer and/or harvested using a non-enzymatic dissociation solution (NEDS) and their adhesion properties were compared to that of control cells cultured on CellBind® and harvested by trypsinization. Interestingly, we observed in a shear stress adhesion test a 44% increase of in the adhesion to VCAM-1 after culture on thermosensitive polymer combined with harvesting with NEDS compared to the control condition (P<0.001). Similarly, adhesion to non-activated HUVEC was increased by 3.2 fold change after Polymer and NEDS compared to CB and Trypsin (P<0.001). However, no significant differences were found when the test was performed on TNFα-activated HUVECs. Together, these results suggest that the culture condition Polymer NEDS has a benefic effect on the adhesion of ADHLSCs to endothelial proteins, particularly under normal conditions where these proteins are expressed at a lower level. These culture conditions could be used clinically in stem cells therapy, to improve the engraftment of the cells especially in the context of non-inflammatory diseases.