RNA methylation machinery and m6A target genes as circulating biomarkers of ulcerative colitis and Crohn's disease: Correlation with disease activity, location, and inflammatory cytokines.

Accurate diagnosis of ulcerative colitis (UC) and Crohn's disease (CD), the main subtypes of inflammatory bowel disease (IBD), has been challenging due to the constraints of the current techniques. N6-methyl adenosine (m6A) regulators have evolved as key players in IBD pathogenesis; however, their relation to its clinical setting is largely unexplored. This study investigated the potential of selected RNA methylation machinery and m6A target genes as serum biomarkers of UC and CD, their predictive and discriminating capabilities, and their correlations with laboratory data, interleukin (IL)-6, interferon-γ, disease activity scores, and pathological features. Fifty UC and 45 CD patients, along with 30 healthy volunteers were enlisted. The mRNA expression levels of the m6A writers methyltransferase-like 3 (METTL3) and Wilms-tumor associated protein (WTAP), and the reader YTH domain family, member 1 (YTHDF1), along with the m6A candidate genes sex determining region Y-box 2 (SOX2), hexokinase 2 (HK2), and ubiquitin-conjugating enzyme E2 L3 (UBE2L3) were upregulated in UC patients, whereas only METTL3, HK2, and UBE2L3 were upregulated in CD patients versus controls. Serum WTAP (AUC = 0.94, 95 %CI = 0.874-1.006) and HK2 (AUC = 0.911, 95 %CI = 0.843-0.980) expression levels showed excellent diagnostic accuracy for UC, METTL3 showed excellent diagnostic accuracy for CD (AUC = 0.91, 95 %CI = 0.828-0.992), meanwhile, WTAP showed excellent discriminative power between the two diseases (AUC = 0.91, 95 %CI = 0.849-0.979). Multivariate logistic analysis unveiled the association of METTL3 and UBE2L3 expression with the risk of CD and UC diagnosis, respectively, controlled by age and sex as confounders. Remarkable correlations were recorded between the gene expression of studied m6A regulators and targets in both diseases. Among UC patients, serum METTL3 and WTAP were correlated with UC extent/type, while WTAP was correlated with IL-6. Among CD patients, serum METTL3 and HK2 were correlated with CD activity index (CDAI) and CD location. In conclusion, m6A regulators and target genes are distinctly expressed in UC and CD clinical samples, correlate with disease activity and extent/location, and could serve as a novel approach to empower the diagnosis and stratification of IBD subtypes.

Relative participation of adenosine and endothelium derived mediators in coronary reactive hyperemia in the dog

The metabolites that mediate coronary reactive hyperemia have not been definitely identified. Although adenosine and endothelium derived substances seem to be involved, their relative contributions have not been defined yet. In the canine coronary circulation, we studied the relative participation of adenosine, nitric oxide and prostacyclin in reactive hyperemia, by measuring the changes produced by interfering with the synthesis or action of these metabolites. The dose-response curve for flow changes vs intracoronary administration of adenosine was displaced to the right after the inhibition of nitric oxide synthesis with N-omega-nitro-L-arginine, revealing that nitric oxide release partly mediates the vasodilator action of adenosine. The inhibition of PGI-2 synthesis with indomethacin did not modify reactive hyperemia. Interference with adenosine action, by administration of adenosine deaminase plus theophylline, decreased reactive hyperemia by 31.0 +/- 4.0 percent (p < 0.001). Inhibition of nitric oxide synthesis decreased reactive hyperemia by a larger (p < 0.005) magnitude, 41.0 +/- 3.9 percent (p < 0.001), revealing the existence of other stimuli for nitric oxide release in reactive hyperemia besides adenosine. Simultaneous inhibition of nitric oxide and PGI-2 syntheses and of adenosine action reduced reactive hyperemia, but the effect was not additive, reaching 49.5 +/- 4.5 percent of control. Since nitric oxide and adenosine are the most important mediators in reactive hyperemia so far described, our results suggest that other metabolites, acting directly or through mediators other than adenosine or nitric oxide, are responsible for about 50 percent of coronary reactive hyperemia

Papel de la adenosina sobre la acción antiarrítmica de los digitálicos / Role of adenosine on the antiarrhythmic action of digitalis

La acción de la adenosina sobre el periodo refractario funcional de los tejidos auriculares y en la cancelación del flutter auricular, es semejante a la de los digitálicos. Tal hecho sugiere la posible existencia de una participación adenílica en la acción digitálica. Por ello medimos las concentraciones plasmáticas de adenosina al infundir ouabaína, e investigamos el efecto del digitálico sobre el periodo refractario de tejidos auriculares y sobre el flutter en condiciones de inhibición colinérgico y bloqueo purinérgico. En perros, se administró ouabaína hasta inducir fibrilación ventricular. Se obtuvo sangre del seno coronario y de la vena femoral, midiendo la adenosina por cromatagrafía de líquidos. El periodo refractario se midió con la ténica del estímulo extra acoplado. El flutter se indujo al estimular el haz internodal posterior. Los resultados muestran que la concentración de adenosina se elevó más de 100 por ciento en plama de seno coronario; el efecto de la ouabaína sobre el periodo refractario no se modificó con la inhibición colinérgica, pero sí fue inhibido por aminofilina; el digitálico modificó su acción en la cancelación del flutter en presencia de aminofilina. Conclusión: en la acción antiarrítmica de los digitálicos parece participar un componente adenílico que resulta de la liberación de adenosina del corazón