The role of infection in the development of non-valvular atrial fibrillation: Up-regulation of Toll-like receptor 2 expression levels on monocytes

SummaryMany studies have suggested that inflammation may participate in the pathogenesis of non-valvular atrial fibrillation (AF). However, it has been unknown by exposure to what the inflammation is caused. Recently, we reported that Toll-like receptor 2 (TLR2) level on monocytes was significantly up-regulated in viral and bacterial infections, but not in non-infectious inflammatory states. Our purpose was to test the hypothesis that expression of TLR2 levels may be up-regulated in patients with non-valvular AF. A total of 48 consecutive patients with non-valvular AF who were hospitalized for catheter ablation were enrolled in this study. TLR2 levels were assayed by using flow-cytometric analysis and compared with volunteers in sinus rhythm (control group, n=24). Additionally, C-reactive protein (CRP) and interleukin-6 (IL-6) levels were assayed, and the left atrial volume indexes (LAVI) in the non-valvular AF group were measured. The results demonstrated that TLR2 levels in the non-valvular AF group were significantly higher than in the control group (median, 4682 vs. 3866 sites/cell; P<0.01). Moreover, non-valvular AF patients had significantly higher IL-6 levels than controls. However, there was no significant difference in CRP levels between the two groups. It was observed in 44 AF patients, in whom pulmonary vein isolation was confirmed to be successful, that the LAVI significantly diminished 1 month after ablation (median, 33.6 vs. 29.5ml/m2; P<0.001), but not the TLR2 and IL-6 levels. Our results implied that an infectious inflammation may participate in the pathogenesis of non-valvular AF

The Japanese space gravitational wave antenna; DECIGO

DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024

DECIGO pathfinder

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article

The status of DECIGO

DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by a differential Fabry-Perot interferometer, and four units of triangular Fabry-Perot interferometers are arranged on heliocentric orbit around the sun. DECIGO is vary ambitious mission, we plan to launch DECIGO in era of 2030s after precursor satellite mission, B-DECIGO. B-DECIGO is essentially smaller version of DECIGO: B-DECIGO consists of three spacecraft arranged in an triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be late 2020s for the present

Catheter ablation of atrial fibrillation guided by complex fractionated atrial electrogram mapping with or without pulmonary vein isolation

Pulmonary vein isolation (PVI) was the main strategy for catheter ablation of atrial fibrillation (AF) until a remarkable report was published by Nademanee et al. in 2004. The ablation targeting complex fractionated atrial electrograms (CFAE) achieved not only a high rate of AF termination but also excellent outcomes in both paroxysmal and persistent AF without isolating pulmonary veins. AF is thought to be caused by random or spiral reentry, as the fixed circuit to maintain AF may not exist, although the CFAE-guided ablation strategy is based on the theory that AF is not entirely random. CFAEs play an important role in identifying AF substrates, and have temporal and spatial stability, thus representing desirable targets for AF ablation; however, CFAE-guided ablation has not been fully replicated by others. In reports showing that CFAE ablation did not yield a good outcome either alone or combined with PVI, the AF termination rates were extremely low. Although AF termination is not mandatory in CFAE-ablation, terminating AF in the majority of patients appears to be necessary to yield good outcomes; therefore, this review will discuss AF ablation guided by CFAE with or without PVI, with particular emphasis given to practical aspects of achieving AF termination