心血管疾患の基盤となる左室肥大と動脈硬化の進行に関与する因子の検討―高血圧症患者および維持血液透析患者を対象とした解析―

2016(平成28)年

Cloning of Hynobius lichenatus (Tohoku hynobiid salamander) p53 and analysis of its expression in response to radiation

Background: Caudata species such as salamanders are easily affected by environmental changes, which can drastically reduce their population. The effects of acute X-rays and chronic γ-irradiation on Hynobius lichenatus, the Japanese Tohoku hynobiid salamander, are known. However, the expression of radiation-inducible genes, such as the DNA-damage checkpoint response gene p53, has not been analyzed in H. lichenatus. This has not occurred because there is no established method for mRNA quantification in H. lichenatus due to a lack of information on available nucleotide sequences corresponding to both radiation-inducible genes and endogenous control genes such as ACTB (β-actin). Results: In this study, we aimed to evaluate the effects of radiation on gene expression in H. lichenatus. Using RNA extracted from irradiated salamanders, we performed rapid amplification of cDNA ends (RACE) and cloned H. lichenatus β-actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and p53. We confirmed that the cloned cDNAs were able to synthesize salamander proteins by western blotting after transfection into cultured HEK293 cells. Proliferation assays using HEK293 cells stably expressing H. lichenatus p53 protein showed that this protein has antiproliferative effects, similar to that of mammalian p53. Furthermore, RT-qPCR analysis using gene-specific primers revealed that p53 mRNA expression in H. lichenatus was upregulated upon exposure to radiation. Conclusion: Our results suggest that H. lichenatus p53 protein take an important role in regulating the cellular responses to various stimuli as mammalian p53 does. Furthermore, our study provides novel data to select appropriate primers to analyze internal control mRNA expression in H. lichenatus and to evaluate p53 expression as a marker of radiation and environmental stimuli

Functional arterial stiffness assessed by changes in pulse wave velocity after exercise reflects the severity of atherosclerosis in hypertensive patients with or without type 2 diabetes mellitus

Objective: The purpose of this study was to determine whether or not functional arterial stiffness, as assessed by changes in brachial-ankle pulse wave velocity (ba-PWV) after exercise, reflects the severity of atherosclerosis in hypertensive patients with or without type 2 diabetes mellitus (DM). Methods: Treated hypertensive patients were divided into hypertension (HT) (n = 102, 62 ± 10 yr) and HT + DM (n = 76, 62 ± 9 yr) groups. Changes in ba-PWV before and after the cycle ergometer exercise at moderate intensity were calculated as an indicator of functional arterial stiffness (⊿PWV). We further divided patients into two subgroups based on ⊿PWV (⊿PWV [-] and ⊿PWV[+] subgroups) and compared their carotid intima-media thickness (cIMT). Stepwise regression analysis was performed with cIMT as a dependent variable, and clinical characteristics, functional arterial stiffness, vascular endothelial function, and autonomic nervous activity as independent variables. Results: cIMT was significantly thicker in the ⊿PWV(+) subgroup than in the ⊿PWV(-) subgroup in both the HT and the HT + DM groups (P < 0.05 and P < 0.05, respectively). Stepwise regression analysis revealed that age, ⊿PWV, and high-density lipoprotein cholesterol (HDL-C) were significant independent limiting factors for cIMT (age: β = 0.314, P < 0.001; ⊿PWV: β = 0.257, P < 0.001; HDL-C: β = -0.205, P < 0.01) (R 2 = 0.21, P < 0.001). Conclusion: Functional arterial stiffness reflects the severity of atherosclerosis in HT patients with or without type 2 DM

Higher Pulmonary Arterial Pressure Was Related to Non-Pulmonary Vein Atrial Tachyarrhythmia

Recurrence of atrial tachyarrhythmias (ATA) following catheter ablation for atrial fibrillation (AF) is often associated with the recovery of conduction into previously isolated pulmonary veins (PVs). Little evidence concerning repeat PV isolation (PVI) and non-PV ATA ablation has been reported. This study aimed to explore the clinical outcome of recurrent ATA ablation after PVI and the difference between patients with and without non PV ATA. A total of 49 patients without structural heart diseases who received catheter ablation for recurrent AF between January 2014 and December 2018 were recruited (prior ablation with PVI only 71.4% and PVI with cavotricuspid isthmus line ablation 28.6%). Patients were divided into two groups according to the presence or absence of non-PV ATA. Most patients (53.1%) experienced very late recurrence with a median duration of 15 months. A total of 15 patients had non-PV ATA and received non-PV ATA ablation whereas 34 patients received only repeat PVI for reconnected PVs. A higher pulmonary arterial systolic pressure (PASP) was associated with non-PV ATA (odds ratio: 1.161; 95% confidence interval: 1.021-1.321; P = 0.023). During 4.7 +/- 1 months, 4/15 (26.7%) and 1/34 (2.9%) patients with and without non-PV ATA, respectively, had ATA recurrence (P = 0.011). The cumulative incidence of ATA recurrence after repeat ablation was significantly lower in patients without non-PV ATA (P = 0.013). In our study, a high PASP was associated with non-PV ATA in patients with recurrent AF. Repeat PVI had a high rate of maintenance of sinus rhythm in patients without non-PV ATA