Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle

The aim of the study was to test the hypothesis that aging causes changes in fiber composition and vascular supply in the human masseter muscle that contribute to impaired jaw function in elderly. The myosin heavy chain (MyHC) composition and capillary supply of muscle fibers in functionally differe...

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Main Author: Zanbil, Angela
Format: Others
Language:English
Published: Umeå universitet, Tandläkarutbildning 2014
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97851
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spelling ndltd-UPSALLA1-oai-DiVA.org-umu-978512015-03-12T04:44:10ZAge Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter MuscleengZanbil, AngelaUmeå universitet, Tandläkarutbildning2014The aim of the study was to test the hypothesis that aging causes changes in fiber composition and vascular supply in the human masseter muscle that contribute to impaired jaw function in elderly. The myosin heavy chain (MyHC) composition and capillary supply of muscle fibers in functionally different parts of the masseter muscle of six elderly and six young subjects (mean age 74 and 22 years) were analyzed with immunohistochemical and morphological methods. The mean muscle fiber area in the old masseter was decreased by 27% compared to the young subjects (1100 vs. 1507 m2, p=0.038). Smaller mean fiber area was observed for all fibers containing only slow MyHCI or fast MyHCII isoforms, but not for fibers co-expressing slow and fast MyHCs. There were no significant differences in the numbers of capillaries around fiber (CAF 1.85 vs. 1.92). When CAF was related to individual fiber area, capillaries around fiber area (CAFA), the capillary supply was significantly higher in elderly (CAFA 1.10 vs. 1.65, p=0.004). This was reflected by a higher capillary density in the old masseter (CD 574 vs. 794, cap/mm2, p=0.002). The loss of muscle mass without any reduction in capillary supply, suggests that the capillary network in the human masseter muscle is rather stable against degradation during aging. This finding is in contrast to previous findings in human limbs, where aging has been reported to decrease both fiber size and capillary network in muscles. We conclude that the ageing process might have different impact on jaw and limb muscles. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97851application/pdfinfo:eu-repo/semantics/openAccess
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language English
format Others
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description The aim of the study was to test the hypothesis that aging causes changes in fiber composition and vascular supply in the human masseter muscle that contribute to impaired jaw function in elderly. The myosin heavy chain (MyHC) composition and capillary supply of muscle fibers in functionally different parts of the masseter muscle of six elderly and six young subjects (mean age 74 and 22 years) were analyzed with immunohistochemical and morphological methods. The mean muscle fiber area in the old masseter was decreased by 27% compared to the young subjects (1100 vs. 1507 m2, p=0.038). Smaller mean fiber area was observed for all fibers containing only slow MyHCI or fast MyHCII isoforms, but not for fibers co-expressing slow and fast MyHCs. There were no significant differences in the numbers of capillaries around fiber (CAF 1.85 vs. 1.92). When CAF was related to individual fiber area, capillaries around fiber area (CAFA), the capillary supply was significantly higher in elderly (CAFA 1.10 vs. 1.65, p=0.004). This was reflected by a higher capillary density in the old masseter (CD 574 vs. 794, cap/mm2, p=0.002). The loss of muscle mass without any reduction in capillary supply, suggests that the capillary network in the human masseter muscle is rather stable against degradation during aging. This finding is in contrast to previous findings in human limbs, where aging has been reported to decrease both fiber size and capillary network in muscles. We conclude that the ageing process might have different impact on jaw and limb muscles.
author Zanbil, Angela
spellingShingle Zanbil, Angela
Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
author_facet Zanbil, Angela
author_sort Zanbil, Angela
title Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
title_short Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
title_full Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
title_fullStr Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
title_full_unstemmed Age Related Differences in Muscle Fiber Composition and Capillary Supply of the Human Masseter Muscle
title_sort age related differences in muscle fiber composition and capillary supply of the human masseter muscle
publisher Umeå universitet, Tandläkarutbildning
publishDate 2014
url http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97851
work_keys_str_mv AT zanbilangela agerelateddifferencesinmusclefibercompositionandcapillarysupplyofthehumanmassetermuscle
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