RESUMEN
Right ventricular (RV) dysfunction (RVD) after orthotopic heart transplantation (OHT) is a common cause of morbidity and mortality. Impella RP Flex was recently approved for RV support as a temporary mechanical circulatory device. We present the first case of its use in managing RVD in a patient after OHT. Here, a 40 year old male patient with familial dilated cardiomyopathy and factor V Leiden mutation presented with Society for Cardiovascular Angiography & Interventions (SCAI) stage B cardiogenic shock. Hemodynamics at admission were indicative of need for intra-aortic balloon pump (IABP) support. Hemodynamics improved and patient underwent OHT. Postoperative day (POD) 1, IABP support was changed to 1:2 and eventually removed. Hemodynamics deteriorated quickly, requiring pharmacologic RV support and diuresis, but refractory RV failure persisted. Impella RP Flex was chosen due to the patient's small size and was placed via the right internal jugular vein on POD 12. The procedure was well tolerated, with the patient ambulatory the following day (POD 13). Impella was removed on POD 25 after 13 days of support. Patient achieved normal kidney, intrinsic rhythm improved sinus rhythm, and ultimately discharged on POD 50. Impella RP flex has emerged as a promising future indication as single or biventricular support postcardiac transplantation.
RESUMEN
AIMS: Human pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) provide a platform to identify and characterize factors that regulate the maturation of CMs. The transition from an immature foetal to an adult CM state entails coordinated regulation of the expression of genes involved in myofibril formation and oxidative phosphorylation (OXPHOS) among others. Lysine demethylase 5 (KDM5) specifically demethylates H3K4me1/2/3 and has emerged as potential regulators of expression of genes involved in cardiac development and mitochondrial function. The purpose of this study is to determine the role of KDM5 in iPSC-CM maturation. METHODS AND RESULTS: KDM5A, B, and C proteins were mainly expressed in the early post-natal stages, and their expressions were progressively downregulated in the post-natal CMs and were absent in adult hearts and CMs. In contrast, KDM5 proteins were persistently expressed in the iPSC-CMs up to 60 days after the induction of myogenic differentiation, consistent with the immaturity of these cells. Inhibition of KDM5 by KDM5-C70 -a pan-KDM5 inhibitor, induced differential expression of 2372 genes, including upregulation of genes involved in fatty acid oxidation (FAO), OXPHOS, and myogenesis in the iPSC-CMs. Likewise, genome-wide profiling of H3K4me3 binding sites by the cleavage under targets and release using nuclease assay showed enriched of the H3K4me3 peaks at the promoter regions of genes encoding FAO, OXPHOS, and sarcomere proteins. Consistent with the chromatin and gene expression data, KDM5 inhibition increased the expression of multiple sarcomere proteins and enhanced myofibrillar organization. Furthermore, inhibition of KDM5 increased H3K4me3 deposits at the promoter region of the ESRRA gene and increased its RNA and protein levels. Knockdown of ESRRA in KDM5-C70-treated iPSC-CM suppressed expression of a subset of the KDM5 targets. In conjunction with changes in gene expression, KDM5 inhibition increased oxygen consumption rate and contractility in iPSC-CMs. CONCLUSION: KDM5 inhibition enhances maturation of iPSC-CMs by epigenetically upregulating the expressions of OXPHOS, FAO, and sarcomere genes and enhancing myofibril organization and mitochondrial function.