Abstract
Low haemocompatibility of left ventricular assist devices (LVAD) surfaces necessitates anticoagulative therapy. Endothelial cell (EC) seeding can support haemocompatibility, however, the availability of autologous ECs is limited. In contrast, allogeneic ECs are readily available in sufficient quantity, but HLA disparities induce harmful immune responses causing EC loss. In this study, we investigated the feasibility of using allogeneic low immunogenic ECs to endothelialize LVAD sintered inflow cannulas (SIC). To reduce the immunogenicity of ECs, we applied an inducible lentiviral vector to deliver short-hairpins RNA to silence HLA class I expression. HLA class I expression on ECs was conditionally silenced by up to 70%. Sufficient and comparable endothelialization rates were achieved with HLA-expressing or HLA-silenced ECs. Cell proliferation was not impaired by cell-to-Sintered Inflow Cannulas (SIC) contact or by silencing HLA expression. The levels of endothelial phenotypic and thrombogenic markers or cytokine secretion profiles remained unaffected. HLA-silenced ECs-coated SIC exhibited reduced thrombogenicity. In contrast to native ECs, HLA-silenced ECs showed lower cell lysis rates when exposed to allogeneic T cells or specific anti-HLA antibodies. Allogeneic HLA-silenced ECs could potentially become a valuable source for LVAD endothelialization to reduce immunogenicity and correspondingly the need for anticoagulative therapy which can entail severe side effects.
Highlights
According to the World Health Organization, cardiovascular diseases are the leading cause of death worldwide, with an increasing incidence and prevalence[1]
We demonstrated the feasibility of endothelializing sintered titanium oxide inflow conduits (SIC) with Endothelial cell (EC)
The use of low immunogenic ECs has the potential to simultaneously increase the haemocompatibility of SIC and decrease the strength of allogeneic immune responses
Summary
According to the World Health Organization, cardiovascular diseases are the leading cause of death worldwide, with an increasing incidence and prevalence[1]. Anticoagulation therapy is prone to complications – high doses can result in severe bleeding, and low doses in thrombosis, which, in turn, can lead to stroke or the need to replace the LVAD4,6,7. To address these complications and provide a secure and long-lasting destination therapy, ‘biologizing’ artificial materials with a suitable cell source offers a promising approach. A biofunctionalized LVAD endothelialized with low immunogenic allogeneic ECs may improve haemocompatibility and reduce or even eliminate the need for anticoagulative therapy. Successful proof of concept of this technology could pave the way for LVADs as a genuine alternative to heart transplantation and a final destination therapy
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