Adipose Tissue-Derived Stem Cells For Pre-Clinical Studies

Abstract

Heart disease is the leading cause of death in the U.S. The most common type of heart disease is coronary artery disease that is caused by a buildup of plaque where treatment options consist of medication and/or surgical interventions. One of the surgical treatments is coronary artery bypass graft surgery that provides the heart with an alternative blood vessel to supply oxygen-rich blood. Despite the many advantages of using an autologous vessel as a graft, the availability is limited. To alleviate the limitation, synthetic vascular grafts have been devised, but thrombosis is a major cause of their failure. The best way to confer anti-thrombogenicity is to endothelialize the lumen because functional endothelium prevents thrombosis. Therefore, tissue-engineered non-thrombogenic grafts are necessary. To make anti-thrombogenic endothelialized blood vessels, it is hypothesized that both mesenchymal stem cells (MSCs) and pericytes are needed to support proliferation and stability of endothelial cells (ECs) under arterial shear stress. This preclinical study utilizes an ovine model. Despite many advantages of the sheep model and its experimental usage for decades, antibodies that are sheep-specific and/ or have cross-reactivity to ovine cells are hardly known. This prevents researchers from doing pre-clinical studies with sheep and slows down the application of findings to clinical trials. Thus, our research team has assessed what commercial antibodies have cross-reactivity to ovine cells/tissue and whether or not they are suitable for distinguishing MSCs from pericytes and vice versa. Based on literature, anti-CD73 antibody clone (TY/23) and anti-NG2 antibody clone (EPR20244) were selected for targeting ovine MSC- and pericyte-specific membrane proteins, respectively. Testing the ovine cross-reactivity of the anti-CD73 antibody was prioritized and is still in the process. To test it, immunocytochemistry (ICC) is used as a major experimental method. In the meantime, adipogenic differentiation of ovine adipose tissue-derived stem cells (oADSCs) was performed to see whether or not the isolated ovine ADSCs have mesenchymal stem cells. If all pieces of experimental results support that the selected antibodies have cross-reactivity to characterize ovine MSCs and pericytes, and MSCs and pericytes work as helper cells as well as a source of ECs to create a rapid and efficient endothelialized tissue-engineered vascular graft, this will accelerate the investigation of the contribution of MSCs and pericytes to non-thrombogenic tissue-engineered grafts.