Age-related changes in glutathione availability and skeletal muscle carbonyl content in healthy rats

During developmental growth, collagens are believed to be continuously deposited into an extracellular matrix which is increasingly stabilized by the formation of covalent cross-links throughout life. However, the age-related changes in rates of synthetic and degradative processes are less well understood. In the present study we measured rates of collagen synthesis in vivo using a flooding dose of unlabelled proline given with [14C]proline and determining production of hydroxy[14C]proline. Degradation of newly synthesized collagen was estimated from the amount of free hydroxy [14C]proline in tissues 30 min after injection. Collagen fractional synthesis rates ranged from about 5%/day in skeletal muscle to 20%/day in hearts of rats aged 1 month. At 15 months of age, collagen fractional synthesis rates had decreased markedly in lung and skin, but in skeletal muscle and heart, rates were unchanged. At 24 months of age, synthesis rates had decreased by at least 10-fold in all tissues, compared with rates at 1 month. The proportion of newly synthesized collagen degraded ranged from 6.4 +/- 0.4% in skin to 61.6 +/- 5.0% in heart at 1 month of age. During aging the proportion degraded increased in all tissues to maximal values at 15 months, ranging from 56 +/- 7% in skin to 96 +/- 1% in heart. These data suggest that there are marked age-related changes in rates of collagen metabolism. They also indicate that synthesis is active even in old animals, where the bulk of collagens produced are destined to be degraded.

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Age-related changes in the reducible cross-links of connectin from human skeletal muscle

Biochemical and Biophysical Research Communications ◽

10.1016/0006-291x(79)91879-5 ◽

1979 ◽

Vol 89 (3) ◽

pp. 1026-1032 ◽

Cited By ~ 10

Author(s):

Katsuyuki Fujii ◽

Haruichi Kurosu

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Age Related ◽

Cross Links ◽

Age Related Changes

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Expression of igf-i and gh-receptor (ghr) mrna in liver and skeletal muscle of different pig breeds

Proceedings of the British Society of Animal Science ◽

10.1017/s0308229600029494 ◽

1995 ◽

Vol 1995 ◽

pp. 183-183

Author(s):

J.M. Brameld ◽

J.L. Atkinson ◽

T.J. Budd ◽

J.C. Saunders ◽

A.M. Salter ◽

...

Keyword(s):

Skeletal Muscle ◽

Energy Availability ◽

Pig Breeds ◽

Gh Receptor ◽

Age Related ◽

Igf I ◽

Class 1 ◽

Cellular Domain ◽

Promoter Usage ◽

Age Related Changes

Previous studies of the porcine GH-IGF axis have demonstrated age related changes in liver, but not LD muscle, in expression of both GH-receptor (GHR) and IGF-I genes (Brameld et al, 1993; 1995), and also effects of energy availability on the expression of IGF-I in liver, but not in LD muscle (Weller et al, 1994). The work described here was carried out to study the expression of IGF-I and GHR mRNA in liver and skeletal muscle from different breeds of pig. The probes used were as described previously (Brameld et al, 1993; 1995; Weller et al, 1993; 1994), and were designed to monitor promoter usage for IGF-I expression, with the two promoters giving rise to class 1 and 2 transcripts, and also expression of the extra-cellular domain of the GH-receptor.

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Bone and Muscle Crosstalk in Aging

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.585644 ◽

2020 ◽

Vol 8 ◽

Author(s):

Chen He ◽

Wenzhen He ◽

Jing Hou ◽

Kaixuan Chen ◽

Mei Huang ◽

...

Keyword(s):

Quality Of Life ◽

Bone Mineral Density ◽

Skeletal Muscle ◽

Bone Cells ◽

The Elderly ◽

Extracellular Vesicle ◽

Mineral Density ◽

Age Related ◽

Age Related Changes

Osteoporosis and sarcopenia are two age-related diseases that affect the quality of life in the elderly. Initially, they were thought to be two independent diseases; however, recently, increasing basic and clinical data suggest that skeletal muscle and bone are both spatially and metabolically connected. The term “osteosarcopenia” is used to define a condition of synergy of low bone mineral density with muscle atrophy and hypofunction. Bone and muscle cells secrete several factors, such as cytokines, myokines, and osteokines, into the circulation to influence the biological and pathological activities in local and distant organs and cells. Recent studies reveal that extracellular vesicles containing microRNAs derived from senescent skeletal muscle and bone cells can also be transported and aid in regulating bone-muscle crosstalk. In this review, we summarize the age-related changes in the secretome and extracellular vesicle-microRNAs secreted by the muscle and bone, and discuss their interactions between muscle and bone cells during aging.

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