Vascular mitochondrial respiratory function: the impact of advancing age.
Am J Physiol Heart Circ Physiol
; 315(6): H1660-H1669, 2018 12 01.
Article
em En
| MEDLINE
| ID: mdl-30192630
ABSTRACT
Little is known about vascular mitochondrial respiratory function and the impact of age. Therefore, skeletal muscle feed arteries were harvested from young (33 ± 7 yr, n = 10), middle-aged (54 ± 5 yr, n = 10), and old (70 ± 7 yr, n = 10) subjects, and mitochondrial respiration as well as citrate synthase (CS) activity were assessed. Complex I (CI) and complex I + II (CI+II) state 3 respiration were greater in young (CI 10.4 ± 0.8 pmol·s-1·mg-1 and CI+II 12.4 ± 0.8 pmol·s-1·mg-1, P < 0.05) than middle-aged (CI 7 ± 0.6 pmol·s-1·mg-1 and CI+II 8.3 ± 0.5 pmol·s-1·mg-1) and old (CI 7.2 ± 0.4 pmol·s-1·mg-1 and CI+II 7.6 ± 0.5 pmol·s-1·mg-1) subjects and, as in the case of complex II (CII) state 3 respiration, were inversely correlated with age [ r = -0.56 (CI), r = -0.7 (CI+II), and r = 0.4 (CII), P < 0.05]. In contrast, state 4 respiration and mitochondria-specific superoxide levels were not different across groups. The respiratory control ratio was greater in young (2.2 ± 0.2, P < 0.05) than middle-aged and old (1.4 ± 0.1 and 1.1 ± 0.1, respectively) subjects and inversely correlated with age ( r = -0.71, P < 0.05). As CS activity was inversely correlated with age ( r = -0.54, P < 0.05), when normalized for mitochondrial content, the age-related differences and relationships with state 3 respiration were ablated. In contrast, mitochondrion-specific state 4 respiration was now lower in young (15 ± 1.4 pmol·s-1·mg-1·U CS-1, P < 0.05) than middle-aged and old (23.4 ± 3.6 and 27.9 ± 3.4 pmol·s-1·mg-1·U CS-1, respectively) subjects and correlated with age ( r = 0.46, P < 0.05). Similarly, superoxide/CS levels were lower in young (0.07 ± 0.01) than old (0.19 ± 0.41) subjects and correlated with age ( r = 0.44, P < 0.05). Therefore, with aging, vascular mitochondrial respiratory function declines, predominantly as a consequence of falling mitochondrial content. However, per mitochondrion, aging likely results in greater mitochondrion-derived oxidative stress, which may contribute to age-related vascular dysfunction. NEW & NOTEWORTHY This study determined, for the first time, that vascular mitochondrial oxidative respiratory capacity, oxidative coupling efficiency, and mitochondrial content fell progressively with advancing age. In terms of single mitochondrion-specific respiration, the age-related differences were completely ablated and the likelihood of free radical production increased progressively with advancing age. This study reveals that vascular mitochondrial respiratory capacity declines with advancing age, as a consequence of falling mitochondrial content, as does oxidative coupling efficiency.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Artérias
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Envelhecimento
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Mitocôndrias
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Am J Physiol Heart Circ Physiol
Assunto da revista:
CARDIOLOGIA
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FISIOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article