TY - JOUR
T1 - Selective decline of the metabolic competence of oversized synaptic mitochondria in the old monkey cerebellum
AU - Bertoni-Freddari, Carlo
AU - Balietti, Marta
AU - Giorgetti, Belinda
AU - Grossi, Yessica
AU - Casoli, Tiziana
AU - Di Stefano, Giuseppina
AU - Perretta, Gemma
AU - Fattoretti, Patrizia
PY - 2008/4/1
Y1 - 2008/4/1
N2 - The morphofunctional features of synaptic mitochondria, positive to the activity of cytochrome oxidase (COX), were investigated in the cerebellar cortex of adult and old monkeys (Macaca fascicularis) to assess the potential age-related changes in the energy metabolism occurring at the neuronal synaptic compartment. The following mitochondrial ultrastructural parameters - numeric density (Nv), volume density (Vv), average volume (V), and average length (Fmax) - were measured by computer-assisted morphometric methods. The ratio (R) area of the COX cytochemical precipitate/area of the mitochondrion was semi-automatically calculated and considered as an estimation of the mitochondrial metabolic competence (MMC), that is, the capacity of single organelles to provide adequate amounts of adenosinetriphosphate. No age-related significant differences were found in any of the ultrastructural parameters taken into account, whereas a significant decrease of R was observed in old animals. In these animals, the quartile distribution of the COX-positive organelles, according to their respective cross-sectional area, showed no significant difference of R when comparing small (I quartile), medium-sized (II quartile), and large (III quartile) mitochondria, while a significant decrease of R was evident in oversized mitochondria (IV quartile). Although our data document an age-related preservation of the morphological features of COX-positive mitochondria in the monkey cerebellum, the significant decrease of R in old animals needs to be considered from the functional standpoint. Since COX is the terminal enzyme of the mitochondrial respiratory chain, the estimation of its activity is regarded as a reliable MMC index; thus our findings, by matching preferential cytochemistry and morphometry, support the hypothesis that the specific functional impairment of enlarged synaptic mitochondria may seriously affect information processing and cell-to-cell communication at synaptic junctional areas with aging.
AB - The morphofunctional features of synaptic mitochondria, positive to the activity of cytochrome oxidase (COX), were investigated in the cerebellar cortex of adult and old monkeys (Macaca fascicularis) to assess the potential age-related changes in the energy metabolism occurring at the neuronal synaptic compartment. The following mitochondrial ultrastructural parameters - numeric density (Nv), volume density (Vv), average volume (V), and average length (Fmax) - were measured by computer-assisted morphometric methods. The ratio (R) area of the COX cytochemical precipitate/area of the mitochondrion was semi-automatically calculated and considered as an estimation of the mitochondrial metabolic competence (MMC), that is, the capacity of single organelles to provide adequate amounts of adenosinetriphosphate. No age-related significant differences were found in any of the ultrastructural parameters taken into account, whereas a significant decrease of R was observed in old animals. In these animals, the quartile distribution of the COX-positive organelles, according to their respective cross-sectional area, showed no significant difference of R when comparing small (I quartile), medium-sized (II quartile), and large (III quartile) mitochondria, while a significant decrease of R was evident in oversized mitochondria (IV quartile). Although our data document an age-related preservation of the morphological features of COX-positive mitochondria in the monkey cerebellum, the significant decrease of R in old animals needs to be considered from the functional standpoint. Since COX is the terminal enzyme of the mitochondrial respiratory chain, the estimation of its activity is regarded as a reliable MMC index; thus our findings, by matching preferential cytochemistry and morphometry, support the hypothesis that the specific functional impairment of enlarged synaptic mitochondria may seriously affect information processing and cell-to-cell communication at synaptic junctional areas with aging.
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U2 - 10.1089/rej.2008.0659
DO - 10.1089/rej.2008.0659
M3 - Article
C2 - 18328003
AN - SCOPUS:42649101666
VL - 11
SP - 387
EP - 391
JO - Rejuvenation Research
JF - Rejuvenation Research
SN - 1549-1684
IS - 2
ER -