Atrial conduction explains the occurrence of the P-wave dispersion phenomenon, but weakly
JOURNAL OF ARRHYTHMIA
Authors: Carmona Puerta, Raimundo; Chavez Gonzalez, Elibet; Rabassa Lopez-Calleja, Magda Alina; Lorenzo Martinez, Elizabeth; Cruz Elizundia, Juan Miguel; Padron Pena, Gustavo; Rodriguez Gonzalez, Fernando
Abstract
Background: P-wave dispersion (PWD) is believed to be caused by inhomogeneous atrial conduction. This statement, however, is based on limited little solid evidence. The aim of this study was to determine the relationship between atrial conduction and PWD by means of invasive electrophysiological studies. Methods: Cross-sectional study in 153 patients with accessory pathways and atrioventricular node reentry tachycardia (AVNRT) undergoing an electrophysiological study. Different atrial conduction times were measured and correlated with PWD. Results: Only the interatrial (P-DCS) and left intra-atrial conduction times (Delta DCS-PCS) showed a significant correlation with PWD, but this correlation was weak. Multivariate linear regression analysis determined that both P-DCS (beta = 0.242;P = .008) and Delta DCS-PCS (beta = 0.295;P < .001) are independent predictors of PWD. Performing the multivariate analysis for arrhythmic substrates, it is observed that only Delta DCS-PCS continued to be an independent predictor of PWD. Analysis of the receiver operating characteristic curves showed that regardless of the types of arrhythmic substrates, PWD discriminates significantly, but moderately, to patients with P-DCS and Delta DCS-PCS >= 75 percentile. Conclusions: Interatrial and intraleft atrial conduction times were directly and significantly correlated with PWD, but only weakly, and were independent predictors of PWD. In general, PWD correctly discriminates patients with high values in interatrial and intraleft atrial conduction times, but moderately. This is maintained in cases with accessory pathways; however, in patients with AVNRT it only does so for intraleft atrial conduction times. Interatrial and intraleft atrial conduction times weakly explains PWD.
Exosomes from dendritic cells with Mettl3 gene knockdown prevent immune rejection in a mouse cardiac allograft model
IMMUNOGENETICS
Authors: Wu, Hongbing; Xu, Zhaojia; Wang, Zhiwei; Ren, Zongli; Li, Luocheng; Ruan, Yongle
Abstract
We have previously demonstrated that Mettl3-silencing dendritic cells (DCs) exhibited immature properties and prolonged allograft survival in a murine heart transplantation model. Exosomes derived from donor DCs (Dex) are involved in the immune rejection of organ transplantation, and blocking Dex transfer may suppress immune rejection. Herein, this study aimed to investigate whether Mettl3 knockdown inhibits the secretion and activity of donor Dex, thereby inhibiting donor Dex-mediated immune rejection. The imDex, mDex, shCtrl-mDex, and shMettl3-mDex were obtained from the culture supernatant of DCs (immature DCs, mature DCs, shCtrl-infected mature DCs, shMettl3-infected mature DCs) derived from donor BALB/c mouse bone marrow and then co-cultured with splenic T cell lymphocyte suspension from recipient C57BL/6 mice in vitro or injected into recipient C57BL/6 mice before the cardiac transplantation. Donor shMettl3-mDex expressed lower concentration of exosomes and lower expression of Mettl3, Dex markers (ICAM-1, MHC-I, MHC-II), as well as lower ability to activate T cell immune response than shCtrl-mDex. Administration of donor shMettl3-mDex attenuated immune rejection after mouse heart transplantation and prolonged the allograft survival. In summary, Mettl3 knockdown inhibits the immune rejection of Dex in a mouse cardiac allograft model.