Association Between the Circumferential Pulmonary Veins Scar and Atrial Fibrillation Recurrence in Patients Undergoing Catheter Ablation of Atrial Fibrillation / 中国循环杂志

Objectives: This study aims to analyze the relationship between late gadolinium enhancement cardiac magnetic resonance imaging (LGE-cMRI) detected scar formation of circumferential pulmonary vein and recurrence rate after catheter ablation in patients with atrial fibrillation, and to compare the efficacy of the single-step cryoballoon ablation with the point-by-point radiofrequency current ablation. Methods: A total of 56 patients with nonvalvular atrial fibrillation who underwent catheter ablation from July 2014 to December 2016 in Fujian Provincial Hospital were enrolled in this study. Among them, 27 patients underwent radiofrequency ablation (RFA), and 29 cases underwent cryoballoon ablation (CBA). Scar formation of circumferential pulmonary vein was detected by LGE-cMRI in all patients at 3 months after ablation. All patients were monitored by telephone or outpatient follow-up (patients complaint, ECG or 24-hour Holter, etc.) at 6 months post ablation. Recurrent atrial tachyarrhythmias were defined as ≥ 30 seconds AF, atrial flutter, or atrial tachycardia. Results: AF recurrence was defined in 13 (23.21%) patients. The ratio of scar formation in circumferential pulmonary vein was significantly lower in recurrence patients than that in the non-recurrent patients ([63.23±5.86]% vs [79.95±7.47]%, P<0.001). The ratio of scar formation in each pulmonary vein of 56 patients was as follows: (76.80±11.60)% in the left superior pulmonary vein, (78.90±10.64)% in the left inferior pulmonary vein, (83.35±9.44)% in the right superior pulmonary vein (P<0.05 vs the left superior pulmonary vein), which was significantly lower in the right inferior pulmonary vein (66.13±13.44)% than above veins (all P<0.05). The ratio of scar formation of all four pulmonary vein was significantly lower in recurrence patients than in the non-recurrent patients, especially in left superior pulmonary vein ([61.19±4.89]% vs [81.52±8.43]%) and the right lower pulmonary vein ([52.47±7.62] % vs [70.26±12.03]%), both P<0.001.Univariate analysis showed that the recurrence rate , the total ratio of scar formation in circumferential pulmonary vein and the ratio of scar formation in recurrence patients were similar between the CBA group and the RFA group. Conclusions: Lower circumferential pulmonary vein scar is associated with higher recurrence rate post catheter ablation in atrial fibrillation patients. The scar formation ratio is low in the right inferior pulmonary vein and the left superior pulmonary vein. The circumferential pulmonary veins scar after cryoablation and radiofrequency catheter ablation is equivalent, indicating the pulmonary vein isolation efficacy of the two procedual methods is comparable.

Effect of hepatocyte growth factor and transforming growth factor-β(1) on atrial fibroblasts fibrosis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effect of hepatocyte growth factor (HGF) and transforming growth factor-β(1) (TGFβ(1)) on the expression of α-smooth muscle actin (α-SMA) and collagen I in human atrial fibroblast in vitro, and to explore the possible molecular mechanism of atrial fibrosis in patients with atrial fibrillation (AF).</p><p><b>METHODS</b>Human atrial fibroblast, isolated from aseptic right atrial appendage tissues of 10 sinus rhythm (SR) and 10 chronic atrial fibrillation (CAF) patients, were cultured with HGF and TGFβ(1). mRNA expressions of collagen I and α-SMA were detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), the protein expression of α-SMA was determined by immunofluorescence and Western blot.</p><p><b>RESULTS</b>(1) Compared with SR group, left atrium was significantly dilated in CAF group (t = 2.692, P < 0.05), the mRNA expression of collagen I and α-SMA of atrial fibroblasts were significantly upregulated (all P < 0.01), mRNA expression of collagen I was positively correlated with left atrial dimension (LAD) (r = 0.836, P = 0.014), AF duration (r = 0.739, P = 0.045) and α-SMA mRNA level (r = 0.886, P = 0.012). (2) Compared with SR group, the expression of α-SMA protein in CAF atrial fibroblasts were significantly increased (P < 0.01). (3) TGFβ(1) further stimulated while HGF significantly attenuated the expression of collagen I and α-SMA in CAF atrial fibroblasts (all P < 0.01).</p><p><b>CONCLUSIONS</b>Increasing expression of collagen I and α-SMA in human atrial fibroblasts might promote atria remodeling leading to the development and sustaining of AF. HGF is involved in the negative regulation on the expression of α-SMA and collagen I.</p>

Establish a transgenic mice model harboring structural genes of hepatitis C virus / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To establish an animal model of HCV transgenic mice to elucidate the pathogenesis of hepatitis C virus infection and function of the viral structural proteins.</p><p><b>METHODS</b>Structural gene of HCV were amplified and recombined into eukaryotic expression vectors, pcDNA4HisMax and pMT/BiP/V5-His A, after their expressive activity was confirmed to detect the structural protein in the transfected COS7 and S2 cells by Western blot. The fertilized expression element, which contained CMV or pMT promoter, structural gene of HCV and polyadenylation signal sequence, was microinjected into 1736 C57BL/6 mouse fertilized ova. The ova were then replanted into the oviducts of 69 pseudopregnant recipient mice.</p><p><b>RESULTS</b>Twenty-five recipient mice were impregnated and later produced 105 newborns; 49 of them died from unknown causes and 57 survived. After the specific HCV structural genes were identified by PCR and Southern blot hybridization, 26 founders were obtained; among them 10 were stable expression mice and 16 were the inducible ones. The rate of founders developed from implanted embryos was only 1.50%. Through hybridization with normal mice, 58 hybrid mice have been obtained at present.</p><p><b>CONCLUSION</b>Two kinds of different transgenic mice of HCV were developed; one is of stable expression, and the other is inducible. This transgenic mice model may create an opportunity for studying the function of the structural gene of HCV and elucidate its pathogenicity.</p>