Background Cardiotoxicity is a leading cause for drug attrition during pharmaceutical

Background Cardiotoxicity is a leading cause for drug attrition during pharmaceutical development and has resulted in numerous preventable patient deaths. dilated cardiomyopathy (DCM). Disease phenotypes were verified in LQT HCM and DCM iPSC-CMs by immunostaining and single cell patch clamp. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and the human cardiotoxicity screening early in NCE development 5 6 In spite of such guidelines drug-induced TdP has resulted in numerous preventable patient deaths and the costly withdrawal of associated pharmacological products from the market 7-9. A central reason for the D-Cycloserine high rates of adverse cardiac drug reactions observed in patients is the limited capacity of preclinical screening assays to detect cardiotoxicity. Current toxicity screens rely on the artificial expression of single cardiac ion channels in genetically transformed cell lines such as Chinese hamster ovary (CHO) or human embryonic kidney (HEK) cells which do not accurately model pertinent genetic cellular or biochemical characteristics of the human heart. The use of CHO and HEK cells to assess cardiotoxicity is impaired by genetic aberrations accumulated in these cells and the failure of ectopically expressed channels to accurately model the same channels found in human cardiomyocytes (CMs) 10 11 In addition blockade of single ion channels alone has proven to be an imperfect measure of QT prolongation as CM electrophysiology is regulated by the concurrent activity of multiple ion channels. Consequently screening of drugs that block single ion channels alone as with CHO or HEK cells can produce false negatives (i.e. Alfuzosin) and false positives (i.e. Verapamil) leading to the market release of potentially lethal drugs and the attrition of valuable drugs respectively 12-15. To improve the accuracy of toxicity screening preclinical drug tests ideally would be conducted on adult human CMs. Unfortunately this has not been feasible in early stage D-Cycloserine drug discovery due to the difficulties in obtaining cardiac tissue from patients and the inability to propagate these cells in culture. The recent derivation of human CMs from embryonic stem cells (hESC-CMs) and induced pluripotent stem cells (hiPSC-CMs) represents a possible method to circumvent these hurdles because both hESC-CMs and hiPSC-CMs possess many of the same electrical characteristics as primary human CMs and can be generated in unlimited quantities from pluripotent cell sources 16 17 The use of patient-specific hiPSC-CMs offers a unique opportunity to transform drug toxicity screening because the majority of individuals who experience adverse cardiac drug responses belong to specific high-risk demographics 18. For example episodes of TdP and sudden cardiac death related to the gastromotility agent cisapride in the mid-1990s were largely absent from the general population and limited to patients with pre-existing heart conditions such as long QT syndrome and heart failure 19. Several recent reports have detailed the derivation hiPSC-CMs from patients with long QT syndrome (LQT) as well as other hereditary cardiac disorders such as LEOPARD syndrome catecholaminergic polymorphic ventricular tachycardia (CPVT) familial hypertrophic cardiomyopathy (HCM) and familial dilated cardiomyopathy (DCM) 20-26. However these reports did not examine whether such patient-specific cells accurately model torsadogenic responses to cardiotoxic drugs. In this study we therefore generated a disease-specific hiPSC-CM library from patients with common hereditary cardiac disorders and tested the capacity of this panel to be used as a surrogate model for prediction of cardiac Goat polyclonal to IgG (H+L). drug toxicity in patient groups at high risk for drug-induced TdP. METHODS Culture and maintenance of undifferentiated hESCs and hiPSCs The H9 hESC line was obtained from WiCell (Madison WI). Characteristics of hiPSC D-Cycloserine lines including mutations are summarized in Supplemental Table 1. hESCs and hiPSCs derived from healthy controls or patients diagnosed with LQT syndrome HCM or DCM were maintained in feeder-free mTeSR1 medium (STEMCELL Technologies Vancouver Canada) on Matrigel-coated (BD Bioscience San Jose CA) plates at 37°C with 5% (vol/vol) CO2. Differentiation of hESCs and.