Determination of hyperglycaemia-induced epc dysfunction using a panel of cellular assays: Validation of experimental murine and human model systems

Abstract

Although human and murine Endothelial Progenitor Cells (EPCs) are routinely used for research, the results can only be imperfectly analyzed due to our limited understanding of source-specific differential responses to stress. Although the routinely used cellular and functional assays are effective for detection of EPC dysfunction (EPD) in single source test systems, there is lack of a universal detection system capable of detecting high glucose (HG) and/or Diabetes mellitus (DM)-induced EPD irrespective of source or site. To remedy this lacuna we compared the test systems from both cell sources. Comparison of sensitivity of various cellular assays revealed that of all the assays performed, only colony formation assays (CFU) showed comparable responses to diabetes/high glucose in both test systems, while cell adhesion assay (CAA), proliferation potential and viability differed in their responses to HG. On the other hand, the functional assays i.e. tubule formation, chemotactic migration assay and CXCR4 and VEGFR2 mRNA expression were uniformly affected by HG in vitro and DM in vivo. Interestingly, other parameters studied i.e. nitric oxide, reactive oxygen species (ROS) and manganese superoxide dismutase (MnSOD) showed dissimilar responses to HG and DM exposure. On this basis, we propose a panel of assays comprising CFU, tubule formation, chemotactic-migration and CXCR4 and VEGFR2 mRNA expression that can accurately detect HG-/DM-induced EPD irrespective of various systemic factors. These assays will also enhance uniformity across data sets and increase accuracy of EPD detection in human and murine systems.