For Publishers
DiscoveryMetadataPeer reviewHostingPublishing
For Researchers
JoinPublishReviewCollect
Register
Blog
About
Search
Advanced search
My ScienceOpen
Search
For Publishers
For Researchers
Blog
About
45
views
123
references
 Top references
cited by
53
    
0 reviews
 Review
0
comments
 Comment
0
recommends
+1 Recommend
0 collections
    0
    shares
      651
      similar
       All similar
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Sarcopenia and Age-Related Endocrine Function

      review-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Sarcopenia, the age-related loss of skeletal muscle, is characterized by a deterioration of muscle quantity and quality leading to a gradual slowing of movement, a decline in strength and power, and an increased risk of fall-related injuries. Since sarcopenia is largely attributed to various molecular mediators affecting fiber size, mitochondrial homeostasis, and apoptosis, numerous targets exist for drug discovery. In this paper, we summarize the current understanding of the endocrine contribution to sarcopenia and provide an update on hormonal intervention to try to improve endocrine defects. Myostatin inhibition seems to be the most interesting strategy for attenuating sarcopenia other than resistance training with amino acid supplementation. Testosterone supplementation in large amounts and at low frequency improves muscle defects with aging but has several side effects. Although IGF-I is a potent regulator of muscle mass, its therapeutic use has not had a positive effect probably due to local IGF-I resistance. Treatment with ghrelin may ameliorate the muscle atrophy elicited by age-dependent decreases in growth hormone. Ghrelin is an interesting candidate because it is orally active, avoiding the need for injections. A more comprehensive knowledge of vitamin-D-related mechanisms is needed to utilize this nutrient to prevent sarcopenia.

          Related collections

          Most cited references123

          • Record: found
          • Abstract: found
          • Article: not found

          Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial.

          Kerrie M Sanders, Amanda Stuart, Elizabeth Williamson … (2010)
          Improving vitamin D status may be an important modifiable risk factor to reduce falls and fractures; however, adherence to daily supplementation is typically poor. To determine whether a single annual dose of 500,000 IU of cholecalciferol administered orally to older women in autumn or winter would improve adherence and reduce the risk of falls and fracture. A double-blind, placebo-controlled trial of 2256 community-dwelling women, aged 70 years or older, considered to be at high risk of fracture were recruited from June 2003 to June 2005 and were randomly assigned to receive cholecalciferol or placebo each autumn to winter for 3 to 5 years. The study concluded in 2008. 500,000 IU of cholecalciferol or placebo. Falls and fractures were ascertained using monthly calendars; details were confirmed by telephone interview. Fractures were radiologically confirmed. In a substudy, 137 randomly selected participants underwent serial blood sampling for 25-hydroxycholecalciferol and parathyroid hormone levels. Women in the cholecalciferol (vitamin D) group had 171 fractures vs 135 in the placebo group; 837 women in the vitamin D group fell 2892 times (rate, 83.4 per 100 person-years) while 769 women in the placebo group fell 2512 times (rate, 72.7 per 100 person-years; incidence rate ratio [RR], 1.15; 95% confidence interval [CI], 1.02-1.30; P = .03). The incidence RR for fracture in the vitamin D group was 1.26 (95% CI, 1.00-1.59; P = .047) vs the placebo group (rates per 100 person-years, 4.9 vitamin D vs 3.9 placebo). A temporal pattern was observed in a post hoc analysis of falls. The incidence RR of falling in the vitamin D group vs the placebo group was 1.31 in the first 3 months after dosing and 1.13 during the following 9 months (test for homogeneity; P = .02). In the substudy, the median baseline serum 25-hydroxycholecalciferol was 49 nmol/L. Less than 3% of the substudy participants had 25-hydroxycholecalciferol levels lower than 25 nmol/L. In the vitamin D group, 25-hydroxycholecalciferol levels increased at 1 month after dosing to approximately 120 nmol/L, were approximately 90 nmol/L at 3 months, and remained higher than the placebo group 12 months after dosing. Among older community-dwelling women, annual oral administration of high-dose cholecalciferol resulted in an increased risk of falls and fractures. anzctr.org.au Identifier: ACTRN12605000658617; isrctn.org Identifier: ISRCTN83409867.
          Article 0 comments Cited 370 times – based on 0 reviews     Review now
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study.

            Carol A Derby, John B. McKinlay, William J Bremner … (2002)
            We used longitudinal data from the Massachusetts Male Aging Study, a large population-based random-sample cohort of men aged 40-70 yr at baseline, to establish normative age trends for serum level of T and related hormones in middle-aged men and to test whether general health status affected the age trends. Of 1,709 men enrolled in 1987-1989, 1,156 were followed up 7-10 yr afterward. By repeated-measures statistical analysis, we estimated simultaneously the cross-sectional age trend of each hormone between subjects within the baseline data, the cross-sectional trend between subjects within the follow-up data, and the longitudinal trend within subjects between baseline and follow-up. Total T declined cross-sectionally at 0.8%/yr of age within the follow-up data, whereas both free and albumin-bound T declined at about 2%/yr, all significantly more steeply than within the baseline data. Sex hormone-binding globulin increased cross-sectionally at 1.6%/yr in the follow-up data, similarly to baseline. The longitudinal decline within subjects between baseline and follow-up was considerably steeper than the cross-sectional trend within measurement times for total T (1.6%/yr) and bioavailable T (2-3%/yr). Dehydroepiandrosterone, dehydroepiandrosterone sulfate, cortisol, and estrone showed significant longitudinal declines, whereas dihydrotestosterone, pituitary gonadotropins, and PRL rose longitudinally. Apparent good health, defined as absence of chronic illness, prescription medication, obesity, or excessive drinking, added 10-15% to the level of several androgens and attenuated the cross-sectional trends in T and LH but did not otherwise affect longitudinal or cross-sectional trends. The paradoxical finding that longitudinal age trends were steeper than cross-sectional trends suggests that incident poor health may accelerate the age-related decline in androgen levels.
            Article 0 comments Cited 337 times – based on 0 reviews     Review now
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Myostatin reduces Akt/TORC1/p70S6K signaling, inhibiting myoblast differentiation and myotube size.

              Anne Ulrike Trendelenburg, Angelika Meyer, Daisy Rohner … (2009)
              Myostatin is a negative regulator of skeletal muscle size, previously shown to inhibit muscle cell differentiation. Myostatin requires both Smad2 and Smad3 downstream of the activin receptor II (ActRII)/activin receptor-like kinase (ALK) receptor complex. Other transforming growth factor-beta (TGF-beta)-like molecules can also block differentiation, including TGF-beta(1), growth differentiation factor 11 (GDF-11), activins, bone morphogenetic protein 2 (BMP-2) and BMP-7. Myostatin inhibits activation of the Akt/mammalian target of rapamycin (mTOR)/p70S6 protein synthesis pathway, which mediates both differentiation in myoblasts and hypertrophy in myotubes. Blockade of the Akt/mTOR pathway, using small interfering RNA to regulatory-associated protein of mTOR (RAPTOR), a component of TOR signaling complex 1 (TORC1), increases myostatin-induced phosphorylation of Smad2, establishing a myostatin signaling-amplification role for blockade of Akt. Blockade of RAPTOR also facilitates myostatin's inhibition of muscle differentiation. Inhibition of TORC2, via rapamycin-insensitive companion of mTOR (RICTOR), is sufficient to inhibit differentiation on its own. Furthermore, myostatin decreases the diameter of postdifferentiated myotubes. However, rather than causing upregulation of the E3 ubiquitin ligases muscle RING-finger 1 (MuRF1) and muscle atrophy F-box (MAFbx), previously shown to mediate skeletal muscle atrophy, myostatin decreases expression of these atrophy markers in differentiated myotubes, as well as other genes normally upregulated during differentiation. These findings demonstrate that myostatin signaling acts by blocking genes induced during differentiation, even in a myotube, as opposed to activating the distinct "atrophy program." In vivo, inhibition of myostatin increases muscle creatine kinase activity, coincident with an increase in muscle size, demonstrating that this in vitro differentiation measure is also upregulated in vivo.
              Article 0 comments Cited 237 times – based on 0 reviews     Review now
                Bookmark
                All references

                Author and article information

                Journal
                Journal ID (nlm-ta): Int J Endocrinol
                Journal ID (iso-abbrev): Int J Endocrinol
                Journal ID (publisher-id): IJE
                Title: International Journal of Endocrinology
                Publisher: Hindawi Publishing Corporation
                ISSN (Print): 1687-8337
                ISSN (Electronic): 1687-8345
                Publication date (Print): 2012
                Publication date (Electronic): 28 May 2012
                Volume: 2012
                Electronic Location Identifier: 127362
                Affiliations
                1Research Center for Physical Fitness, Sports and Health, Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi 441-8580, Japan
                2School of Dentistry, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293, Japan
                Author notes

                Academic Editor: Huan Cai

                Article
                DOI: 10.1155/2012/127362
                PMC ID: 3368374
                PubMed ID: 22690213
                SO-VID: 724ca4e8-0884-46ef-80c7-0e3c2e9f17d6
                Copyright © Copyright © 2012 K. Sakuma and A. Yamaguchi.
                License:

                This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                Date received : 1 December 2011
                Date accepted : 22 February 2012
                Categories
                Subject: Review Article

                ScienceOpen disciplines: Endocrinology & Diabetes
                Data availability:
                ScienceOpen disciplines: Endocrinology & Diabetes

                Comments

                Comment on this article

                scite_

                Similar content651

                See all similar

                Cited by50

                See all cited by

                Most referenced authors1,871

                See all reference authors