Cardiac aging is characterized by alterations in contractility and intracellular calcium ([Ca2+]i) homeostasis. It has been suggested that oxidative stress may be involved in this process. We and others have reported that in cardiomyopathies the NADPH oxidase (NOX)-derived superoxide is increased, with a negative impact on [Ca2+]i and contractility. We tested the hypothesis that in the aged heart, [Ca2+]i handling and contractility are disturbed by NOX-derived superoxide. For this we used adults (≈5 month-old) and aged (20–24 month-old) rats. Contractility was evaluated in isolated hearts, challenged with isoproterenol. To assess [Ca2+]i, isolated cardiac myocytes were field-stimulated and [Ca2+]i was monitored with fura-2. Cardiac concentration-response to isoproterenol was depressed in aged compared to adults hearts (p < 0.005), but was restored by NOX inhibitors apocynin and VAS2870. In isolated cardiomyocytes, apocynin increased the amplitude of [Ca2+]i in aged myocytes (p < 0.05). Time-50 [Ca2+]i decay was increased in aged myocytes (p < 0.05) and reduced towards normal by NOX inhibition. In addition, we found that myofilaments Ca2+ sensitivity was reduced in aged myocytes (p < 0.05), and was further reduced by apocynin. NOX2 expression along with NADPH oxidase activity was increased in aged hearts. Phospholamban phosphorylation (Ser16/Thr17) after isoproterenol treatment was reduced in aged hearts compared to adults and was restored by apocynin treatment (p < 0.05). In conclusion, β-adrenergic-induced contractility was depressed in aged hearts, and NOX inhibition restored back to normal. Moreover, altered Ca2+ handling in aged myocytes was also improved by NOX inhibition. These results suggest a NOX-dependent effect in aged myocytes at the level of Ca2+ handling proteins and myofilaments.

Cardiac aging is characterized by alterations in contractility and intracellular calcium ([Ca2+]i) homeostasis. It has been suggested that oxidative stress may be involved in this process. We and others have reported that in cardiomyopathies the NADPH oxidase (NOX)-derived superoxide is increased, with a negative impact on [Ca2+]i and contractility. We tested the hypothesis that in the aged heart, [Ca2+]i handling and contractility are disturbed by NOX-derived superoxide. Contractility was evaluated isolated hearts, challenged with isoproterenol. To assess [Ca2+]i, isolated cardiac myocytes were field-stimulated and [Ca2+]i was monitored with fura-2. Cardiac concentration-response to isoproterenol was depressed in aged compared to adults hearts (p &lt; 0.005), but was restored by NOX inhibitors apocynin and VAS2870. In isolated cardiomyocytes, apocynin increased the amplitude of [Ca2+]i in aged myocytes (p &lt; 0.05). Time-50 [Ca2+]i decay was increased in aged myocytes (p &lt; 0.05) and reduced towards normal by NOX inhibition. In addition, we found that myofilaments Ca2+ sensitivity was reduced in aged myocytes (p &lt; 0.05), and further reduced by apocynin. Finally SERCA levels but not phospholamban were reduced in aged hearts (p &lt; 0.05). In conclusion, &beta;-adrenergic‒induced contractility was depressed in aged hearts, and NOX inhibition restored back to normal. Moreover, altered Ca2+ handling in aged myocytes was also improved by NOX inhibition. These results suggest a NOX-dependent effect in aged myocytes at the level of Ca2+ handling proteins and myofilaments.

RESUMEN: Las Bandas de Hunter-Schreger (BHS), son bandas claras y oscuras, que se aprecian en el esmalte debido a la distínta curvatura de los prismas del esmalte, resultan ser ampliamente mencionadas en estudios, tanto odontológicos como antropológicos, mas no se ven reflejadas en Terminologia Histologica. El objetivo del presente trabajo fue realizar un análisis del término BHS, con el fin de proponerlo como nuevo término histológico, y así poder ser incluido en Terminologia Histologica por la Federative International Programme for Anatomical Terminology (FIPAT). Luego del análisis en textos de estudio y publicaciones científicas, proponemos en reemplazo del término BHS, por dos términos: diazone prismatica (diá del griego διá 'a través de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra') y parazone prismatica (pará gr. 'a lo largo de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra'), definiendo así términos más descriptivos y que no utilizan epónimos, tal como lo establece la Terminología Internacional. Proponer nuevos términos que estén más acorde con los señalado por la International Federation of Associations of Anatomists (IFAA) y la propia terminología, presenta grandes desafíos; un término no sólo es una palabra que hace referencia a una estructura morfológica, sino que también es una unidad del lenguaje, que une a la comunidad morfológica en un solo lenguaje. Por lo cual proponemos que el término sea incluido por la FIPAT en próximas discusiones.