TRPM7 is down‐regulated in both left atria and left ventricle of ischaemic cardiomyopathy patients and highly related to changes in ventricular function

AIMS: The kinase ion channel transient receptor potential melastatin 7 (TRPM7) is considered a modulator of cardiac fibrosis progression; nevertheless, we lack of studies analysing its role in human ischaemic cardiomyopathy (ICM). Our objective was to analyse the expression of genes encoding cardiac ion channels in human ICM, focusing on the alterations in mRNA levels of TRPM7 and its relationship with changes in the ventricular function. METHODS AND RESULTS: RNA‐sequencing was carried out in 13 left ventricular (LV) samples of patients with ICM compared with a control group (n = 10). The analysis revealed a total of 25 ion channel genes differentially expressed. We performed an RTqPCR analysis of the TRPM7 mRNA in LV and left atrial samples and found that it was down‐regulated in both cavities (−1.43‐fold and −1.52‐fold, respectively). Atrial TRPM7 mRNA levels showed an excellent and inverse relationships with the depressed ejection fraction (r = −0.724, P = 0.042) and with the mitral A wave (r = −0.938, P = 0.006). CONCLUSIONS: We report the down‐regulation of TRPM7 in tissue samples from both left atria and left ventricle in patients with ICM. We found an inverse relationship between both cardiac chambers mRNA levels with LV dysfunction, suggesting an important role of TRPM7 in the left atrial and LV functional depression found in this cardiomyopathy.