Effects of orally administered Euglena gracilis and its reserve polysaccharide, paramylon, on gastric dysplasia in A4gnt knockout mice.

Euglena gracilis is widely utilized as food or supplement to promote human and animal health, as it contains rich nutrients. In this study, we administered spray-dried powder of E. gracilis and paramylon, ß-glucan stored in E. gracilis cells, to A4gnt knockout (KO) mice. A4gnt KO mice are a mutant mouse model that spontaneously develops gastric cancer through hyperplasia-dysplasia-adenocarcinoma sequence in the antrum of the stomach, and we observed the effects of E. gracilis and paramylon on the early involvements of A4gnt KO mice. Male and female 10-week-old A4gnt KO mice and their age-matched wildtype C57BL/6J mice were orally administered with 50 mg of E. gracilis or paramylon suspended in saline or saline as a control. After 3-week administration, animals were euthanatized and the stomach was examined histopathologically and immunohistochemically. Gene expression patterns of the stomach, which have been reported to be altered with A4gnt KO, and IgA concentration in small intestine were also analyzed with real-time PCR and ELISA, respectively. Administration of Euglena significantly reduced the number of stimulated CD3-positive T-lymphocytes in pyloric mucosa of A4gnt KO mice and tend to reduce polymorphonuclear leukocytes infiltration. Euglena administration further downregulated the expression of Il11 and Cxcl1 of A4gnt KO mice. Euglena administration also affected IgA concentration in small intestinal contents of A4gnt KO mice. Paramylon administration reduced the number of CD3-positive lymphocytes in pyloric mucosa of A4gnt KO mice, and downregulated the expressions of Il11 and Ccl2 of A4gnt KO mice. Although we found no significant effects on gross and microscopic signs of gastric dysplasia and cell proliferation, the present study suggests that the administration of Euglena and paramylon may ameliorate the early involvements of A4gnt mice through the effects on inflammatory reactions in the gastric mucosa. The cancer-preventing effects should be studied with long-term experiments until actual gastric cancer formation.

Differences in the structural characteristics and distribution of epicardial adipose tissue between left and right atrial fibrillation.

Aims: Right atrial (RA) fibrillation (RAF) was previously characterized by initiation from RA ectopies, presence of a right-to-left dominant frequency gradient during atrial fibrillation (AF), and augmentation of the gradient by adenosine triphosphate infusion. We investigated structural characteristics of the bi-atria and epicardial adipose tissue (EAT) volume in patients with RAF. Methods and results: By using multidetector computed tomography, RA, left atrial (LA), right and LA appendage (RAA and LAA, respectively) volumes, pulmonary vein (PV) sizes, and EAT volumes were compared between the RAF group (n = 8) and LA fibrillation (LAF) group (n = 32). Compared with the LAF group, the LA volume was smaller (median 81.3 [95% CI, 74.2-88.5] vs. 64.5 [54.8-74.2] mL/m2; P = 0.04), the LAA volume was smaller (10.1 [9.0-11.3] vs. 6.5 [4.5-8.5] mL/m2; P = 0.008), and the RAA volume was larger (10.8 [9.1-12.4] vs. 14.1 [11.6-16.6] mL/m2; P = 0.044) in the RAF group. The RA volume was not significantly different between the groups (73.6 [66.8-80.3] vs. 68.1 [57.1-79.1] mL/m2; P = 0.47). The RAF group had smaller PVs (1.44 [1.33-1.55] vs. 1.12 [0.94-1.30] cm2/m2 for the left inferior PV; P = 0.01). Both the LA-EAT and RA-EAT volumes were smaller in the RAF group than the LAF group (4.2 [2.8-5.6] vs. 9.1 [7.8-10.4] mL/m2; P < 0.001 and 5.3 [4.3-6.3] vs. 9.5 [8.4-10.6] mL/m2; P < 0.001, respectively). Conclusion: RAF was structurally characterized by predominant RAA enlargement, small left atrium, and less EAT surrounding the atria. Electrical properties that determine the features of AF (RAF vs. LAF) may be genetically linked to structural properties.

Trade-off between elimination of premature ventricular complexes and loss of synchronized left ventricular pacing improved cardiac function in a patient with heart failure.

Synchronized left ventricular pacing (sLVP) via adaptive cardiac resynchronization therapy (aCRT) algorithm might enhance the efficacy of CRT. A 71-year-old female was admitted with the diagnosis of heart failure. Electrocardiograms revealed left bundle branch block with QRS width of 144 ms, and frequent premature ventricular complexes (PVCs). A CRT device was implanted, and sLVP via a CRT algorithm was provided. Frequent PVCs arising from the His-bundle suppressed effective sLVP percentage. Radiofrequency application at the His-bundle successfully eliminated the PVCs, but induced complete atrioventricular (AV) block, leading to loss of sLVP. These procedures remarkably improved the patient's cardiac function, suggesting the advantage of PVC elimination overweighed the disadvantage of loss of sLVP.

Right-to-left frequency gradient during atrial fibrillation initiated by right atrial ectopies and its augmentation by adenosine triphosphate: Implications of right atrial fibrillation.

BACKGROUND: A left-to-right dominant frequency (DF) gradient commonly exists in paroxysmal atrial fibrillation (AF). AF initiated by right atrial (RA) ectopy (AF-RAE) is rare. OBJECTIVE: This study aimed to investigate characteristics of AF-RAE using pharmacological maneuvers and spectral analysis. METHODS: Seventy-nine consecutive patients referred for catheter ablation of paroxysmal AF were enrolled. Infusions of isoproterenol and adenosine triphosphate (ATP) were used to induce AF. Patients with AF-RAE and patients with AF initiated only by pulmonary vein (PV) ectopies were classified into the RA-ectopy group (n = 7[9%]) and PV-ectopy group (n = 32[41%]), respectively. ATP was also injected during ongoing AF to unmask the driver of AF. High RA, coronary sinus, and PV-left atrial junction electrograms and electrocardiogram lead V1 underwent spectral analyses. RESULTS: Patients in the RA-ectopy group were younger (51 ± 13 years vs 63 ± 7 years; P = .01) and more commonly had a family history of AF (71% vs 9%; P < .001) than patients in the PV-ectopy group. There was a baseline right-to-left DF gradient in the RA-ectopy group (PV-left atrial junction: 6.0 ± 0.4 Hz; coronary sinus: 5.7 ± 0.6 Hz; RA: 7.3 ± 0.8 Hz; P < .05) in contrast to a left-to-right DF gradient in the PV-ectopy group (5.9 ± 0.8, 5.3 ± 0.7, 5.2 ± 0.8 Hz; P < .01). ATP injection predominantly increased the DF of the high RA in the RA-ectopy group and augmented a right-to-left DF gradient (7.9 ± 1.8, 7.6 ± 1.0, 10.7 ± 0.7 Hz; P < .001), whereas it augmented a left-to-right DF gradient in the PV-ectopy group (7.9 ± 1.0, 6.4 ± 0.5, 6.6 ± 1.2 Hz; P < .05). CONCLUSION: A rare type of paroxysmal AF initiated by RA ectopy may be maintained by a reentrant driver localized in the RA (so-called RA fibrillation).