A, statistical analysis of MTT assays (n = 8) showing that, when cardiomyocytes were cultured under conditions of simulated ischaemia for 6 h, the silencing of TPCs significantly decreased cell viability vs. controls (cardiomyocytes subjected to simulated ischaemia and transfected with a siRNA negative control with no homology to known gene sequences). B, statistical analysis of MTT assays (n = 8) confirming that, in cardiomyocytes subjected to serum deprivation for 24 h, knockdown of TPC2, with or without TPC1, also decreased cell viability vs. controls. Statistical significance (Mann–Whitney U test): *P ≤ 0.05; **P ≤ 0.01.