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Yarrow JF, Wnek RD, Conover CF, Reynolds MC, Buckley KH, Kura JR, Sutor TW, Otzel DM, Mattingly AJ, Croft S, Aguirre JI, Borst SE, Beck DT, McCullough DJ. Bone loss after severe spinal cord injury coincides with reduced bone formation and precedes bone blood flow deficits. J Appl Physiol (1985) 2021; 131:1288-1299. [PMID: 34473574 DOI: 10.1152/japplphysiol.00444.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diminished bone perfusion develops in response to disuse and has been proposed as a mechanism underlying bone loss. Bone blood flow (BF) has not been investigated within the unique context of severe contusion spinal cord injury (SCI), a condition that produces neurogenic bone loss that is precipitated by disuse and other physiological consequences of central nervous system injury. Herein, 4-mo-old male Sprague-Dawley rats received T9 laminectomy (SHAM) or laminectomy with severe contusion SCI (n = 20/group). Time course assessments of hindlimb bone microstructure and bone perfusion were performed in vivo at 1- and 2-wk postsurgery via microcomputed tomography (microCT) and intracardiac microsphere infusion, respectively, and bone turnover indices were determined via histomorphometry. Both groups exhibited cancellous bone loss beginning in the initial postsurgical week, with cancellous and cortical bone deficits progressing only in SCI thereafter. Trabecular bone deterioration coincided with uncoupled bone turnover after SCI, as indicated by signs of ongoing osteoclast-mediated bone resorption and a near-complete absence of osteoblasts and cancellous bone formation. Bone BF was not different between groups at 1 wk, when both groups displayed bone loss. In comparison, femur and tibia perfusion was 30%-40% lower in SCI versus SHAM at 2 wk, with the most pronounced regional BF deficits occurring at the distal femur. Significant associations existed between distal femur BF and cancellous and cortical bone loss indices. Our data provide the first direct evidence indicating that bone BF deficits develop in response to SCI and temporally coincide with suppressed bone formation and with cancellous and cortical bone deterioration.NEW & NOTEWORTHY We provide the first direct evidence indicating femur and tibia blood flow (BF) deficits exist in conscious (awake) rats after severe contusion spinal cord injury (SCI), with the distal femur displaying the largest BF deficits. Reduced bone perfusion temporally coincided with unopposed bone resorption, as indicated by ongoing osteoclast-mediated bone resorption and a near absence of surface-level bone formation indices, which resulted in severe cancellous and cortical microstructural deterioration after SCI.
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Affiliation(s)
- Joshua F Yarrow
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida.,Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida.,Division of Endocrinology, Diabetes, and Metabolism, University of Florida College of Medicine, Gainesville, Florida
| | - Russell D Wnek
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Christine F Conover
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Michael C Reynolds
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Kinley H Buckley
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Jayachandra R Kura
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Tommy W Sutor
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Dana M Otzel
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Alex J Mattingly
- Geriatrics Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Summer Croft
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - J Ignacio Aguirre
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Stephen E Borst
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Darren T Beck
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
| | - Danielle J McCullough
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
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2
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Yarrow JF, Kok HJ, Phillips EG, Conover CF, Lee J, Bassett TE, Buckley KH, Reynolds MC, Wnek RD, Otzel DM, Chen C, Jiron JM, Graham ZA, Cardozo C, Vandenborne K, Bose PK, Aguirre JI, Borst SE, Ye F. Locomotor training with adjuvant testosterone preserves cancellous bone and promotes muscle plasticity in male rats after severe spinal cord injury. J Neurosci Res 2019; 98:843-868. [PMID: 31797423 DOI: 10.1002/jnr.24564] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/31/2019] [Accepted: 11/11/2019] [Indexed: 12/15/2022]
Abstract
Loading and testosterone may influence musculoskeletal recovery after spinal cord injury (SCI). Our objectives were to determine (a) the acute effects of bodyweight-supported treadmill training (TM) on hindlimb cancellous bone microstructure and muscle mass in adult rats after severe contusion SCI and (b) whether longer-term TM with adjuvant testosterone enanthate (TE) delivers musculoskeletal benefit. In Study 1, TM (40 min/day, 5 days/week, beginning 1 week postsurgery) did not prevent SCI-induced hindlimb cancellous bone loss after 3 weeks. In Study 2, TM did not attenuate SCI-induced plantar flexor muscles atrophy nor improve locomotor recovery after 4 weeks. In our main study, SCI produced extensive distal femur and proximal tibia cancellous bone deficits, a deleterious slow-to-fast fiber-type transition in soleus, lower muscle fiber cross-sectional area (fCSA), impaired muscle force production, and levator ani/bulbocavernosus (LABC) muscle atrophy after 8 weeks. TE alone (7.0 mg/week) suppressed bone resorption, attenuated cancellous bone loss, constrained the soleus fiber-type transition, and prevented LABC atrophy. In comparison, TE+TM concomitantly suppressed bone resorption and stimulated bone formation after SCI, produced near-complete cancellous bone preservation, prevented the soleus fiber-type transition, attenuated soleus fCSA atrophy, maintained soleus force production, and increased LABC mass. 75% of SCI+TE+TM animals recovered voluntary over-ground hindlimb stepping, while no SCI and only 20% of SCI+TE animals regained stepping ability. Positive associations between testosterone and locomotor function suggest that TE influenced locomotor recovery. In conclusion, short-term TM alone did not improve bone, muscle, or locomotor recovery in adult rats after severe SCI, while longer-term TE+TM provided more comprehensive musculoskeletal benefit than TE alone.
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Affiliation(s)
- Joshua F Yarrow
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Division of Endocrinology, Diabetes, and Metabolism, University of Florida College of Medicine, Gainesville, FL, USA
| | - Hui Jean Kok
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Ean G Phillips
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Christine F Conover
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Jimmy Lee
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Taylor E Bassett
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Kinley H Buckley
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Michael C Reynolds
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Russell D Wnek
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Dana M Otzel
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - Cong Chen
- Divison of Orthopedics and Rehabilitation, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jessica M Jiron
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Zachary A Graham
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA.,Departments of Medicine, Icahn School of Medicine, New York, NY, USA
| | - Christopher Cardozo
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA.,Departments of Medicine, Icahn School of Medicine, New York, NY, USA.,Rehabilitation Medicine, Icahn School of Medicine, New York, NY, USA
| | - Krista Vandenborne
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - Prodip K Bose
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Department of Physiological Sciences, University of Florida, Gainesville, FL, USA.,Division of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jose Ignacio Aguirre
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Stephen E Borst
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Fan Ye
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
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Otzel DM, Conover CF, Ye F, Phillips EG, Bassett T, Wnek RD, Flores M, Catter A, Ghosh P, Balaez A, Petusevsky J, Chen C, Gao Y, Zhang Y, Jiron JM, Bose PK, Borst SE, Wronski TJ, Aguirre JI, Yarrow JF. Longitudinal Examination of Bone Loss in Male Rats After Moderate-Severe Contusion Spinal Cord Injury. Calcif Tissue Int 2019; 104:79-91. [PMID: 30218117 PMCID: PMC8349506 DOI: 10.1007/s00223-018-0471-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/30/2018] [Indexed: 02/07/2023]
Abstract
To elucidate mechanisms of bone loss after spinal cord injury (SCI), we evaluated the time-course of cancellous and cortical bone microarchitectural deterioration via microcomputed tomography, measured histomorphometric and circulating bone turnover indices, and characterized the development of whole bone mechanical deficits in a clinically relevant experimental SCI model. 16-weeks-old male Sprague-Dawley rats received T9 laminectomy (SHAM, n = 50) or moderate-severe contusion SCI (n = 52). Outcomes were assessed at 2-weeks, 1-month, 2-months, and 3-months post-surgery. SCI produced immediate sublesional paralysis and persistent hindlimb locomotor impairment. Higher circulating tartrate-resistant acid phosphatase 5b (bone resorption marker) and lower osteoblast bone surface and histomorphometric cancellous bone formation indices were present in SCI animals at 2-weeks post-surgery, suggesting uncoupled cancellous bone turnover. Distal femoral and proximal tibial cancellous bone volume, trabecular thickness, and trabecular number were markedly lower after SCI, with the residual cancellous network exhibiting less trabecular connectivity. Periosteal bone formation indices were lower at 2-weeks and 1-month post-SCI, preceding femoral cortical bone loss and the development of bone mechanical deficits at the distal femur and femoral diaphysis. SCI animals also exhibited lower serum testosterone than SHAM, until 2-months post-surgery, and lower serum leptin throughout. Our moderate-severe contusion SCI model displayed rapid cancellous bone deterioration and more gradual cortical bone loss and development of whole bone mechanical deficits, which likely resulted from a temporal uncoupling of bone turnover, similar to the sequalae observed in the motor-complete SCI population. Low testosterone and/or leptin may contribute to the molecular mechanisms underlying bone deterioration after SCI.
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Affiliation(s)
- Dana M Otzel
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Christine F Conover
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Fan Ye
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Ean G Phillips
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Taylor Bassett
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Russell D Wnek
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Micah Flores
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Andrea Catter
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Payal Ghosh
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Alexander Balaez
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Jason Petusevsky
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Cong Chen
- Department of Orthopedics and Rehabilitation, University of Florida, PO Box 112727, Gainesville, FL, 32611, USA
| | - Yongxin Gao
- University of Florida College of Medicine, Jacksonville, FL, 32209, USA
| | - Yi Zhang
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
| | - Jessica M Jiron
- Department of Physiological Sciences, University of Florida, PO Box 100144, Gainesville, FL, 32610, USA
| | - Prodip K Bose
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA
- Department of Physiological Sciences, University of Florida, PO Box 100144, Gainesville, FL, 32610, USA
- Department of Neurology, University of Florida, HSC PO Box 100236, Gainesville, FL, 32610, USA
| | - Stephen E Borst
- Department of Applied Physiology and Kinesiology, University of Florida, PO Box 118205, Gainesville, FL, 32611, USA
| | - Thomas J Wronski
- Department of Physiological Sciences, University of Florida, PO Box 100144, Gainesville, FL, 32610, USA
| | - J Ignacio Aguirre
- Department of Physiological Sciences, University of Florida, PO Box 100144, Gainesville, FL, 32610, USA
| | - Joshua F Yarrow
- Research Service, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Research 151, Gainesville, FL, 32608, USA.
- Division of Endocrinology, Diabetes, and Metabolism, University of Florida College of Medicine, 1600 SW Archer Road, Gainesville, FL, 32610, USA.
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Otzel DM, Lee J, Ye F, Borst SE, Yarrow JF. Activity-Based Physical Rehabilitation with Adjuvant Testosterone to Promote Neuromuscular Recovery after Spinal Cord Injury. Int J Mol Sci 2018; 19:ijms19061701. [PMID: 29880749 PMCID: PMC6032131 DOI: 10.3390/ijms19061701] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/22/2022] Open
Abstract
Neuromuscular impairment and reduced musculoskeletal integrity are hallmarks of spinal cord injury (SCI) that hinder locomotor recovery. These impairments are precipitated by the neurological insult and resulting disuse, which has stimulated interest in activity-based physical rehabilitation therapies (ABTs) that promote neuromuscular plasticity after SCI. However, ABT efficacy declines as SCI severity increases. Additionally, many men with SCI exhibit low testosterone, which may exacerbate neuromusculoskeletal impairment. Incorporating testosterone adjuvant to ABTs may improve musculoskeletal recovery and neuroplasticity because androgens attenuate muscle loss and the slow-to-fast muscle fiber-type transition after SCI, in a manner independent from mechanical strain, and promote motoneuron survival. These neuromusculoskeletal benefits are promising, although testosterone alone produces only limited functional improvement in rodent SCI models. In this review, we discuss the (1) molecular deficits underlying muscle loss after SCI; (2) independent influences of testosterone and locomotor training on neuromuscular function and musculoskeletal integrity post-SCI; (3) hormonal and molecular mechanisms underlying the therapeutic efficacy of these strategies; and (4) evidence supporting a multimodal strategy involving ABT with adjuvant testosterone, as a potential means to promote more comprehensive neuromusculoskeletal recovery than either strategy alone.
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Affiliation(s)
- Dana M Otzel
- Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Jimmy Lee
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Fan Ye
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Stephen E Borst
- Department of Applied Physiology, Kinesiology and University of Florida College of Health and Human Performance, Gainesville, FL 32603, USA.
| | - Joshua F Yarrow
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
- Division of Endocrinology, Diabetes and Metabolism, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Skinner JW, Otzel DM, Bowser A, Nargi D, Agarwal S, Peterson MD, Zou B, Borst SE, Yarrow JF. Muscular responses to testosterone replacement vary by administration route: a systematic review and meta-analysis. J Cachexia Sarcopenia Muscle 2018; 9. [PMID: 29542875 PMCID: PMC5989848 DOI: 10.1002/jcsm.12291] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Inconsistent fat-free mass (FFM) and muscle strength responses have been reported in randomized clinical trials (RCTs) administering testosterone replacement therapy (TRT) to middle-aged and older men. Our objective was to conduct a meta-analysis to determine whether TRT improves FFM and muscle strength in middle-aged and older men and whether the muscular responses vary by TRT administration route. METHODS Systematic literature searches of MEDLINE/PubMed and the Cochrane Library were conducted from inception through 31 March 2017 to identify double-blind RCTs that compared intramuscular or transdermal TRT vs. placebo and that reported assessments of FFM or upper-extremity or lower-extremity strength. Studies were identified, and data were extracted and validated by three investigators, with disagreement resolved by consensus. Using a random effects model, individual effect sizes (ESs) were determined from 31 RCTs reporting FFM (sample size: n = 1213 TRT, n = 1168 placebo) and 17 reporting upper-extremity or lower-extremity strength (n = 2572 TRT, n = 2523 placebo). Heterogeneity was examined, and sensitivity analyses were performed. RESULTS When administration routes were collectively assessed, TRT was associated with increases in FFM [ES = 1.20 ± 0.15 (95% CI: 0.91, 1.49)], total body strength [ES = 0.90 ± 0.12 (0.67, 1.14)], lower-extremity strength [ES = 0.77 ± 0.16 (0.45, 1.08)], and upper-extremity strength [ES = 1.13 ± 0.18 (0.78, 1.47)] (P < 0.001 for all). When administration routes were evaluated separately, the ES magnitudes were larger and the per cent changes were 3-5 times greater for intramuscular TRT than for transdermal formulations vs. respective placebos, for all outcomes evaluated. Specifically, intramuscular TRT was associated with a 5.7% increase in FFM [ES = 1.49 ± 0.18 (1.13, 1.84)] and 10-13% increases in total body strength [ES = 1.39 ± 0.12 (1.15, 1.63)], lower-extremity strength [ES = 1.39 ± 0.17 (1.07, 1.72)], and upper-extremity strength [ES = 1.37 ± 0.17 (1.03, 1.70)] (P < 0.001 for all). In comparison, transdermal TRT was associated with only a 1.7% increase in FFM [ES = 0.98 ± 0.21 (0.58, 1.39)] and only 2-5% increases in total body [ES = 0.55 ± 0.17 (0.22, 0.88)] and upper-extremity strength [ES = 0.97 ± 0.24 (0.50, 1.45)] (P < 0.001). Interestingly, transdermal TRT produced no change in lower-extremity strength vs. placebo [ES = 0.26 ± 0.23 (-0.19, 0.70), P = 0.26]. Subanalyses of RCTs limiting enrolment to men ≥60 years of age produced similar results. CONCLUSIONS Intramuscular TRT is more effective than transdermal formulations at increasing LBM and improving muscle strength in middle-aged and older men, particularly in the lower extremities.
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Affiliation(s)
- Jared W Skinner
- Geriatrics Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA
| | - Dana M Otzel
- Brain Rehabilitation Research Center (BRRC) Center of Excellence, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA
| | - Andrew Bowser
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA
| | - Daniel Nargi
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA
| | - Sanjay Agarwal
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA
| | - Mark D Peterson
- School of Medicine, Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI, USA
| | - Baiming Zou
- Departments of Biostatistics, University of Florida, Gainesville, FL, 32611, USA
| | - Stephen E Borst
- Geriatrics Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA.,Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Joshua F Yarrow
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, 32608, USA.,Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
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Phillips EG, Beggs LA, Ye F, Conover CF, Beck DT, Otzel DM, Ghosh P, Bassit ACF, Borst SE, Yarrow JF. Effects of pharmacologic sclerostin inhibition or testosterone administration on soleus muscle atrophy in rodents after spinal cord injury. PLoS One 2018; 13:e0194440. [PMID: 29579075 PMCID: PMC5868788 DOI: 10.1371/journal.pone.0194440] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 03/02/2018] [Indexed: 12/24/2022] Open
Abstract
Sclerostin is a circulating osteocyte-derived glycoprotein that negatively regulates Wnt-signaling after binding the LRP5/LRP6 co-receptors. Pharmacologic sclerostin inhibition produces bone anabolic effects after spinal cord injury (SCI), however, the effects of sclerostin-antibody (Scl-Ab) on muscle morphology remain unknown. In comparison, androgen administration produces bone antiresorptive effects after SCI and some, but not all, studies have reported that testosterone treatment ameliorates skeletal muscle atrophy in this context. Our purposes were to determine whether Scl-Ab prevents hindlimb muscle loss after SCI and compare the effects of Scl-Ab to testosterone enanthate (TE), an agent with known myotrophic effects. Male Sprague-Dawley rats aged 5 months received: (A) SHAM surgery (T8 laminectomy), (B) moderate-severe contusion SCI, (C) SCI+TE (7.0 mg/wk, im), or (D) SCI+Scl-Ab (25 mg/kg, twice weekly, sc). Twenty-one days post-injury, SCI animals exhibited a 31% lower soleus mass in comparison to SHAM, accompanied by >50% lower soleus muscle fiber cross-sectional area (fCSA) (p<0.01 for all fiber types). Scl-Ab did not prevent soleus atrophy, consistent with the relatively low circulating sclerostin concentrations and with the 91–99% lower LRP5/LRP6 gene expressions in soleus versus tibia (p<0.001), a tissue with known anabolic responsiveness to Scl-Ab. In comparison, TE partially prevented soleus atrophy and increased levator ani/bulbocavernosus (LABC) mass by 30–40% (p<0.001 vs all groups). The differing myotrophic responsiveness coincided with a 3-fold higher androgen receptor gene expression in LABC versus soleus (p<0.01). This study provides the first direct evidence that Scl-Ab does not prevent soleus muscle atrophy in rodents after SCI and suggests that variable myotrophic responses in rodent muscles after androgen administration are influenced by androgen receptor expression.
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Affiliation(s)
- Ean G. Phillips
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
| | - Luke A. Beggs
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
| | - Fan Ye
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
| | - Christine F. Conover
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
| | - Darren T. Beck
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, United States of America
| | - Dana M. Otzel
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
| | - Payal Ghosh
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, United States of America
| | - Anna C. F. Bassit
- Orthopedics Department, Shriners Hospital for Children, Montreal, QC, Canada
| | - Stephen E. Borst
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States of America
| | - Joshua F. Yarrow
- Research Service, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States of America
- Division of Endocrinology, Diabetes and Metabolism, University of Florida College of Medicine, Gainesville, FL, United States of America
- * E-mail:
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7
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Yarrow JF, Phillips EG, Conover CF, Bassett TE, Chen C, Teurlings T, Vasconez A, Alerte J, Prock H, Jiron JM, Flores M, Aguirre JI, Borst SE, Ye F. Testosterone Plus Finasteride Prevents Bone Loss without Prostate Growth in a Rodent Spinal Cord Injury Model. J Neurotrauma 2017; 34:2972-2981. [PMID: 28338402 DOI: 10.1089/neu.2016.4814] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have reported that testosterone-enanthate (TE) prevents the musculoskeletal decline occurring acutely after spinal cord injury (SCI), but results in a near doubling of prostate mass. Our purpose was to test the hypothesis that administration of TE plus finasteride (FIN; type II 5α-reductase inhibitor) would prevent the chronic musculoskeletal deficits in our rodent severe contusion SCI model, without inducing prostate enlargement. Forty-three 16-week-old male Sprague-Dawley rats received: 1) SHAM surgery (T9 laminectomy); 2) severe (250 kdyne) contusion SCI; 3) SCI+TE (7.0 mg/week, intramuscular); or 4) SCI+TE+FIN (5 mg/kg/day, subcutaneous). At 8 weeks post-surgery, SCI animals exhibited reduced serum testosterone and levator ani/bulbocavernosus (LABC) muscle mass, effects that were prevented by TE. Cancellous and cortical (periosteal) bone turnover (assessed by histomorphometry) were elevated post-SCI, resulting in reduced distal femur cancellous and cortical bone mass (assessed by microcomputed tomography). TE treatment normalized cancellous and cortical bone turnover and maintained cancellous bone mass at the level of SHAM animals, but produced prostate enlargement. FIN coadministration did not inhibit the TE-induced musculoskeletal effects, but prevented prostate growth. Neither drug regimen prevented SCI-induced cortical bone loss, although no differences in whole bone strength were present among groups. Our findings indicate that TE+FIN prevented the chronic cancellous bone deficits and LABC muscle loss in SCI animals without inducing prostate enlargement, which provides a rationale for the inclusion of TE+FIN in multimodal therapeutic interventions intended to alleviate the musculoskeletal decline post-SCI.
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Affiliation(s)
- Joshua F Yarrow
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida.,2 Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
| | - Ean G Phillips
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Christine F Conover
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Taylor E Bassett
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Cong Chen
- 3 Department of Orthopedics and Rehabilitation, University of Florida , Gainesville, Florida
| | - Tyler Teurlings
- 3 Department of Orthopedics and Rehabilitation, University of Florida , Gainesville, Florida
| | - Andrea Vasconez
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Jonathan Alerte
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Hannah Prock
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Jessica M Jiron
- 4 Physiological Sciences, University of Florida , Gainesville, Florida
| | - Micah Flores
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - J Ignacio Aguirre
- 4 Physiological Sciences, University of Florida , Gainesville, Florida
| | - Stephen E Borst
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida.,2 Department of Applied Physiology and Kinesiology, University of Florida , Gainesville, Florida
| | - Fan Ye
- 1 Research Service, Malcom Randall Department of Veterans Affairs Medical Center , North Florida/South Georgia Veterans Health System, Gainesville, Florida
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Otzel DM, Bassett T, Chen C, Teurlings T, Conover CF, Flores M, Ye F, Phillips EG, Catter A, Borst SE, Yarrow JF. Bone Mechanical Strength Deficits Following a Contusion Spinal Cord Injury in Rats. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000517985.07820.f5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Conover CF, Yarrow JF, Garrett TJ, Ye F, Quinlivan EP, Cannady DF, Peterson MD, Borst SE. High Prevalence of Low Serum Biologically Active Testosterone in Older Male Veterans. J Am Med Dir Assoc 2017; 18:366.e17-366.e24. [PMID: 28214238 DOI: 10.1016/j.jamda.2016.12.077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/16/2016] [Accepted: 12/23/2016] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Assess the prevalence of hypogonadism in older male Veterans by comparing direct measurements of total testosterone (T) and bioavailable testosterone (BioT) versus indirect BioT values derived from existing and newly developed regression analyses. DESIGN Cohort study. SETTING Malcom Randall VA Medical Center, Gainesville, FL. PARTICIPANTS Community-dwelling male Veterans aged 60 and older (n = 203). MEASUREMENTS Total T, BioT, albumin, sex hormone-binding globulin (SHBG), and body mass index were evaluated. Blood values were assessed via liquid chromatography-tandem mass spectrometry (LC-MS/MS) and clinical or commercially available immunoassays to compare accuracy among assessment techniques. Existing and newly developed multiple regression analyses were evaluated to assess accuracy in predicting BioT. RESULTS Total T was 13.80 ± 6.25 nmol/L (398 ± 180 ng/dL) and was low (≤10.4 nmol/L or ≤300 ng/dL) in 34% of participants. SHBG was 58 ± 35 nmol/L and elevated (≥62 nmol/L) in 36% of participants. BioT was 1.94 ± 0.97 nmol/L (56 ± 28 ng/dL), with 72% of participants below the clinical cutoff (≤2.43 nmol/L or ≤70 ng/dL). Albumin was within the normal clinical range. Total T and BioT measured via immunoassay and LC-MS/MS were moderately to highly correlated, with no differences between assessment methods. Several existing predictive equations overestimated BioT by 74% to 166% within our cohort (P < .001). A newly developed regression model that included total T, SHBG, albumin, and age more accurately predicted BioT, with values correlated (r = 0.508, P < .001) and comparable to LC-MS/MS. CONCLUSION In our cohort, the prevalence of low total T was higher and low BioT was markedly higher than reported in the general age-matched population, indicating a greater incidence of hypogonadism in older male Veterans. In addition, existing empiric formulae, derived from other populations produced BioT values that were considerably greater than those directly measured, whereas our newly developed regression analysis provides improved predictive capabilities for older male Veterans.
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Affiliation(s)
- Christine F Conover
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL.
| | - Joshua F Yarrow
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL
| | - Timothy J Garrett
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL
| | - Fan Ye
- North Florida Foundation for Research and Education, University of Florida, Gainesville, FL
| | - Eoin P Quinlivan
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL
| | - Darryl F Cannady
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL
| | - Mark D Peterson
- Department of Physical Medicine and Rehabilitation, University of Michigan School of Medicine, Ann Arbor, MI
| | - Stephen E Borst
- Geriatrics Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL; Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL
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Holland AM, Roberts MD, Mumford PW, Mobley CB, Kephart WC, Conover CF, Beggs LA, Balaez A, Otzel DM, Yarrow JF, Borst SE, Beck DT. Testosterone inhibits expression of lipogenic genes in visceral fat by an estrogen-dependent mechanism. J Appl Physiol (1985) 2016; 121:792-805. [PMID: 27539493 DOI: 10.1152/japplphysiol.00238.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/15/2016] [Indexed: 02/01/2023] Open
Abstract
The influence of the aromatase enzyme on the chronic fat-sparing effects of testosterone requires further elucidation. Our purpose was to determine whether chronic anastrozole (AN, an aromatase inhibitor) treatment alters testosterone-mediated lipolytic/lipogenic gene expression in visceral fat. Ten-month-old Fischer 344 rats (n = 6/group) were subjected to sham surgery (SHAM), orchiectomy (ORX), ORX + treatment with testosterone enanthate (TEST, 7.0 mg/wk), or ORX + TEST + AN (0.5 mg/day), with drug treatment beginning 14 days postsurgery. At day 42, ORX animals exhibited nearly undetectable serum testosterone and 29% higher retroperitoneal fat mass than SHAM animals (P < 0.001). TEST produced a ∼380-415% higher serum testosterone than SHAM (P < 0.001) and completely prevented ORX-induced visceral fat gain (P < 0.001). Retroperitoneal fat was 21% and 16% lower in ORX + TEST than SHAM (P < 0.001) and ORX + TEST + AN (P = 0.007) animals, while serum estradiol (E2) was 62% (P = 0.024) and 87% (P = 0.010) higher, respectively. ORX stimulated lipogenic-related gene expression in visceral fat, demonstrated by ∼84-154% higher sterol regulatory element-binding protein-1 (SREBP-1, P = 0.023), fatty acid synthase (P = 0.01), and LPL (P < 0.001) mRNA than SHAM animals, effects that were completely prevented in ORX + TEST animals (P < 0.01 vs. ORX for all). Fatty acid synthase (P = 0.061, trend) and LPL (P = 0.043) mRNA levels were lower in ORX + TEST + AN than ORX animals and not different from SHAM animals but remained higher than in ORX + TEST animals (P < 0.05). In contrast, the ORX-induced elevation in SREBP-1 mRNA was not prevented by TEST + AN, with SREBP-1 expression remaining ∼117-171% higher than in SHAM and ORX + TEST animals (P < 0.01). Across groups, visceral fat mass and lipogenic-related gene expression were negatively associated with serum testosterone, but not E2 Aromatase inhibition constrains testosterone-induced visceral fat loss and the downregulation of key lipogenic genes at the mRNA level, indicating that E2 influences the visceral fat-sparing effects of testosterone.
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Affiliation(s)
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama; Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
| | | | | | | | - Christine F Conover
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida
| | - Luke A Beggs
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Alexander Balaez
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Dana M Otzel
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Joshua F Yarrow
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Stephen E Borst
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Darren T Beck
- School of Kinesiology, Auburn University, Auburn, Alabama; Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
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Abstract
Androgens and estrogens influence skeletal development and maintenance in males. However, the relative contributions of the circulating sex steroid hormones that originate from testicular/adrenal secretion versus those produced locally in bone via intracrine action require further elucidation. Our novel hypothesis is that testosterone exerts direct protective effects on the adult male skeleton independently of the actions of 5α-reductase or aromatase.
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Affiliation(s)
- Joshua F Yarrow
- 1Research Service, Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System; 2Departments of Applied Physiology and Kinesiology, and 3Physiological Sciences, University of Florida; and 4Geriatrics Research, Education, and Clinical Center (GRECC), Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL
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12
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Dalbo VJ, Roberts MD, Mobley CB, Ballmann C, Kephart WC, Fox CD, Santucci VA, Conover CF, Beggs LA, Balaez A, Hoerr FJ, Yarrow JF, Borst SE, Beck DT. Testosterone and trenbolone enanthate increase mature myostatin protein expression despite increasing skeletal muscle hypertrophy and satellite cell number in rodent muscle. Andrologia 2016; 49. [PMID: 27246614 DOI: 10.1111/and.12622] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 01/03/2023] Open
Abstract
The androgen-induced alterations in adult rodent skeletal muscle fibre cross-sectional area (fCSA), satellite cell content and myostatin (Mstn) were examined in 10-month-old Fisher 344 rats (n = 41) assigned to Sham surgery, orchiectomy (ORX), ORX + testosterone (TEST; 7.0 mg week-1 ) or ORX + trenbolone (TREN; 1.0 mg week-1 ). After 29 days, animals were euthanised and the levator ani/bulbocavernosus (LABC) muscle complex was harvested for analyses. LABC muscle fCSA was 102% and 94% higher in ORX + TEST and ORX + TREN compared to ORX (p < .001). ORX + TEST and ORX + TREN increased satellite cell numbers by 181% and 178% compared to ORX, respectively (p < .01), with no differences between conditions for myonuclear number per muscle fibre (p = .948). Mstn protein was increased 159% and 169% in the ORX + TEST and ORX + TREN compared to ORX (p < .01). pan-SMAD2/3 protein was ~30-50% greater in ORX compared to SHAM (p = .006), ORX + TEST (p = .037) and ORX + TREN (p = .043), although there were no between-treatment effects regarding phosphorylated SMAD2/3. Mstn, ActrIIb and Mighty mRNAs were lower in ORX, ORX + TEST and ORX + TREN compared to SHAM (p < .05). Testosterone and trenbolone administration increased muscle fCSA and satellite cell number without increasing myonuclei number, and increased Mstn protein levels. Several genes and signalling proteins related to myostatin signalling were differentially regulated by ORX or androgen therapy.
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Affiliation(s)
- V J Dalbo
- Medical and Applied Sciences, Central Queensland University, Rockhampton, Qld, Australia
| | - M D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C B Mobley
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C Ballmann
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - W C Kephart
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C D Fox
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - V A Santucci
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C F Conover
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA
| | - L A Beggs
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - A Balaez
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - F J Hoerr
- Veterinary Diagnostic Pathology LLC, Auburn, AL, USA
| | - J F Yarrow
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - S E Borst
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - D T Beck
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, USA
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Mobley CB, Mumford PW, Kephart WC, Conover CF, Beggs LA, Balaez A, Yarrow JF, Borst SE, Beck DT, Roberts MD. Effects of testosterone treatment on markers of skeletal muscle ribosome biogenesis. Andrologia 2016; 48:967-977. [PMID: 26781353 DOI: 10.1111/and.12539] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2015] [Indexed: 12/14/2022] Open
Abstract
The effects of testosterone (TEST) treatment on markers of skeletal muscle ribosome biogenesis in vitro and in vivo were examined. C2 C12 myotubes were treated with 100 nm TEST for short-term (24-h) and longer-term (96-h) treatments. Moreover, male 10-month-old Fischer 344 rats were housed for 4 weeks, and the following groups were included in this study: (i) Sham-operated (Sham) rats, (ii) orchiectomised rats (ORX) and (iii) ORX+TEST-treated rats (7.0 mg week-1 ). For in vitro data, TEST treatment increased c-Myc mRNA expression by 38% (P = 0.004) after 96 h, but did not affect total RNA, 47S pre-rRNA, Raptor mRNA, Nop56 mRNA, Bop1 mRNA, Ncl mRNA at 24 h or 96 h following the treatment. For in vivo data, ORX decreased levator ani/bulbocavernosus (LABC) myofibril protein versus Sham (P = 0.006), whereas ORX+TEST (P = 0.015) rescued this atrophic effect. ORX also decreased muscle ribosome content (total RNA) compared to Sham (P = 0.046), whereas ORX+TEST tended to rescue this effect (P = 0.057). However, other markers of ribosome biogenesis including c-Myc mRNA, Nop56 mRNA, Bop1 mRNA, Ncl mRNA decreased with ORX independently of TEST treatments (P < 0.05). Finally, lower phospho-(Ser235/236)-to-total rps6 protein and lower rpl5 protein levels existed in ORX+TEST rats versus other treatments, suggesting that chronic TEST treatment may lower translational capacity.
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Affiliation(s)
- C B Mobley
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - P W Mumford
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - W C Kephart
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C F Conover
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - L A Beggs
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - A Balaez
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - J F Yarrow
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - S E Borst
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.,Geriatric Research Education and Clinical Center (GRECC), Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - D T Beck
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA
| | - M D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA. .,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA.
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Borst SE, Yarrow JF. Injection of testosterone may be safer and more effective than transdermal administration for combating loss of muscle and bone in older men. Am J Physiol Endocrinol Metab 2015; 308:E1035-42. [PMID: 25898953 PMCID: PMC6189635 DOI: 10.1152/ajpendo.00111.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/16/2015] [Indexed: 01/18/2023]
Abstract
The value of testosterone replacement therapy (TRT) for older men is currently a topic of intense debate. While US testosterone prescriptions have tripled in the past decade (9), debate continues over the risks and benefits of TRT. TRT is currently prescribed for older men with either low serum testosterone (T) or low T plus accompanying symptoms of hypogonadism. The normal range for serum testosterone is 300 to 1,000 ng/dl. Serum T ≤ 300 ng/dl is considered to be low, and T ≤ 250 is considered to be frank hypogonadism. Most experts support TRT for older men with frank hypogonadism and symptoms. Treatment for men who simply have low T remains somewhat controversial. TRT is most frequently administered by intramuscular (im) injection of long-acting T esters or transdermally via patch or gel preparations and infrequently via oral administration. TRT produces a number of established benefits in hypogonadal men, including increased muscle mass and strength, decreased fat mass, increased bone mineral density, and improved sexual function, and in some cases those benefits are dose dependent. For example, doses of TRT administered by im injection are typically higher than those administered transdermally, which results in greater musculoskeletal benefits. TRT also produces known risks including development of polycythemia (Hct > 50) in 6% of those treated, decrease in HDL, breast tenderness and enlargement, prostate enlargement, increases in serum PSA, and prostate-related events and may cause suppression of the hypothalamic-pituitary-gonadal axis. Importantly, TRT does not increase the risk of prostate cancer. Putative risks include edema and worsening of sleep apnea. Several recent reports have also indicated that TRT may produce cardiovascular (CV) risks, while others report no risk or even benefit. To address the potential CV risks of TRT, we have recently reported via meta-analysis that oral TRT increases CV risk and suggested that the CV risk profile for im TRT may be better than that for oral or transdermal TRT.
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Affiliation(s)
- Stephen E Borst
- Geriartic Research, Education and Clinical Center, Veterans Affairs Medical Center, Gainesville, Florida; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Joshua F Yarrow
- Research Service, Veterans Affairs Medical Center, Gainesville, Florida; and Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
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Yarrow JF, Ye F, Conover CF, Ghosh P, Balaez A, Mantione JM, Eisler E, Miller J, Tang D, Otzel DM, Borst SE. Time-course Of Cancellous And Cortical Bone Loss In A Rodent Contusion Spinal Cord Injury Model. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478418.92943.60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jia H, Sullivan CT, McCoy SC, Yarrow JF, Morrow M, Borst SE. Review of health risks of low testosterone and testosterone administration. World J Clin Cases 2015; 3:338-344. [PMID: 25879005 PMCID: PMC4391003 DOI: 10.12998/wjcc.v3.i4.338] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/29/2014] [Accepted: 02/02/2015] [Indexed: 02/05/2023] Open
Abstract
Hypogonadism is prevalent in older men and testosterone replacement therapy (TRT) for older hypogonadal men is a promising therapy. However, a number of important clinical concerns over TRT safety remain unsolved due to a lack of large-scale randomized clinical trials directly comparing the health risks of untreated hypogonadism vs long-term use of TRT. Meta-analyses of clinical trials of TRT as of 2010 have identified three major adverse events resulting from TRT: polycythemia, an increase in prostate-related events, and a slight reduction in serum high-density lipoprotein cholesterol. There are other purported health risks but their incidence can be neither confirmed nor denied based on the small number of subjects that have been studied to date. Furthermore, subsequent literature is equivocal with regard to the safety and utility of TRT and this topic has been subject to contentious debate. Since January 2014, the United States Food and Drug Administration has released two official announcements regarding the safety of TRT and clinical monitoring the risks in TRT users. Additionally, the health risks related to the clinical presentation of low or declining testosterone levels not been resolved in the current literature. Because TRT is prescribed in the context of putative risks resulting from reduced testosterone levels, we reviewed the epidemiology and reported risks of low testosterone levels. We also highlight the current information about TRT utilization, the risks most often claimed to be associated with TRT, and current or emerging alternatives to TRT.
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Beggs LA, Ye F, Ghosh P, Beck DT, Conover CF, Balaez A, Miller JR, Phillips EG, Zheng N, Williams AA, Aguirre JI, Wronski TJ, Bose PK, Borst SE, Yarrow JF. Sclerostin inhibition prevents spinal cord injury-induced cancellous bone loss. J Bone Miner Res 2015; 30:681-9. [PMID: 25359699 PMCID: PMC8367350 DOI: 10.1002/jbmr.2396] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 01/22/2023]
Abstract
Spinal cord injury (SCI) results in rapid and extensive sublesional bone loss. Sclerostin, an osteocyte-derived glycoprotein that negatively regulates intraskeletal Wnt signaling, is elevated after SCI and may represent a mechanism underlying this excessive bone loss. However, it remains unknown whether pharmacologic sclerostin inhibition ameliorates bone loss subsequent to SCI. Our primary purposes were to determine whether a sclerostin antibody (Scl-Ab) prevents hindlimb cancellous bone loss in a rodent SCI model and to compare the effects of a Scl-Ab to that of testosterone-enanthate (TE), an agent that we have previously shown prevents SCI-induced bone loss. Fifty-five (n = 11-19/group) skeletally mature male Sprague-Dawley rats were randomized to receive: (A) SHAM surgery (T8 laminectomy), (B) moderate-severe (250 kilodyne) SCI, (C) 250 kilodyne SCI + TE (7.0 mg/wk, im), or (D) 250 kilodyne SCI + Scl-Ab (25 mg/kg, twice weekly, sc) for 3 weeks. Twenty-one days post-injury, SCI animals exhibited reduced hindlimb cancellous bone volume at the proximal tibia (via μCT and histomorphometry) and distal femur (via μCT), characterized by reduced trabecular number and thickness. SCI also reduced trabecular connectivity and platelike trabecular structures, indicating diminished structural integrity of the remaining cancellous network, and produced deficits in cortical bone (femoral diaphysis) strength. Scl-Ab and TE both prevented SCI-induced cancellous bone loss, albeit via differing mechanisms. Specifically, Scl-Ab increased osteoblast surface and bone formation, indicating direct bone anabolic effects, whereas TE reduced osteoclast surface with minimal effect on bone formation, indicating antiresorptive effects. The deleterious microarchitectural alterations in the trabecular network were also prevented in SCI + Scl-Ab and SCI + TE animals, whereas only Scl-Ab completely prevented the reduction in cortical bone strength. Our findings provide the first evidence indicating that sclerostin inhibition represents a viable treatment to prevent SCI-induced cancellous and cortical bone deficits and provides preliminary rationale for future clinical trials focused on evaluating whether Scl-Ab prevents osteoporosis in the SCI population.
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Affiliation(s)
- Luke A Beggs
- Research Service, Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
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Zou B, Jin B, Koch GG, Zhou H, Borst SE, Menon S, Shuster JJ. On model selections for repeated measurement data in clinical studies. Stat Med 2015; 34:1621-33. [PMID: 25645442 DOI: 10.1002/sim.6414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 12/16/2014] [Accepted: 12/17/2014] [Indexed: 11/07/2022]
Abstract
Repeated measurement designs have been widely used in various randomized controlled trials for evaluating long-term intervention efficacies. For some clinical trials, the primary research question is how to compare two treatments at a fixed time, using a t-test. Although simple, robust, and convenient, this type of analysis fails to utilize a large amount of collected information. Alternatively, the mixed-effects model is commonly used for repeated measurement data. It models all available data jointly and allows explicit assessment of the overall treatment effects across the entire time spectrum. In this paper, we propose an analytic strategy for longitudinal clinical trial data where the mixed-effects model is coupled with a model selection scheme. The proposed test statistics not only make full use of all available data but also utilize the information from the optimal model deemed for the data. The performance of the proposed method under various setups, including different data missing mechanisms, is evaluated via extensive Monte Carlo simulations. Our numerical results demonstrate that the proposed analytic procedure is more powerful than the t-test when the primary interest is to test for the treatment effect at the last time point. Simulations also reveal that the proposed method outperforms the usual mixed-effects model for testing the overall treatment effects across time. In addition, the proposed framework is more robust and flexible in dealing with missing data compared with several competing methods. The utility of the proposed method is demonstrated by analyzing a clinical trial on the cognitive effect of testosterone in geriatric men with low baseline testosterone levels.
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Affiliation(s)
- Baiming Zou
- Department of Biostatistics, University of Florida, Gainesville, FL 32611, U.S.A
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Yarrow JF, Conover CF, Beggs LA, Beck DT, Otzel DM, Balaez A, Combs SM, Miller JR, Ye F, Aguirre JI, Neuville KG, Williams AA, Conrad BP, Gregory CM, Wronski TJ, Bose PK, Borst SE. Testosterone dose dependently prevents bone and muscle loss in rodents after spinal cord injury. J Neurotrauma 2014; 31:834-45. [PMID: 24378197 DOI: 10.1089/neu.2013.3155] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Androgen administration protects against musculoskeletal deficits in models of sex-steroid deficiency and injury/disuse. It remains unknown, however, whether testosterone prevents bone loss accompanying spinal cord injury (SCI), a condition that results in a near universal occurrence of osteoporosis. Our primary purpose was to determine whether testosterone-enanthate (TE) attenuates hindlimb bone loss in a rodent moderate/severe contusion SCI model. Forty (n=10/group), 14 week old male Sprague-Dawley rats were randomized to receive: (1) Sham surgery (T9 laminectomy), (2) moderate/severe (250 kdyne) SCI, (3) SCI+Low-dose TE (2.0 mg/week), or (4) SCI+High-dose TE (7.0 mg/week). Twenty-one days post-injury, SCI animals exhibited a 77-85% reduction in hindlimb cancellous bone volume at the distal femur (measured via μCT) and proximal tibia (measured via histomorphometry), characterized by a >70% reduction in trabecular number, 13-27% reduction in trabecular thickness, and increased trabecular separation. A 57% reduction in cancellous volumetric bone mineral density (vBMD) at the distal femur and a 20% reduction in vBMD at the femoral neck were also observed. TE dose dependently prevented hindlimb bone loss after SCI, with high-dose TE fully preserving cancellous bone structural characteristics and vBMD at all skeletal sites examined. Animals receiving SCI also exhibited a 35% reduction in hindlimb weight bearing (triceps surae) muscle mass and a 22% reduction in sublesional non-weight bearing (levator ani/bulbocavernosus [LABC]) muscle mass, and reduced prostate mass. Both TE doses fully preserved LABC mass, while only high-dose TE ameliorated hindlimb muscle losses. TE also dose dependently increased prostate mass. Our findings provide the first evidence indicating that high-dose TE fully prevents hindlimb cancellous bone loss and concomitantly ameliorates muscle loss after SCI, while low-dose TE produces much less profound musculoskeletal benefit. Testosterone-induced prostate enlargement, however, represents a potential barrier to the clinical implementation of high-dose TE as a means of preserving musculoskeletal tissue after SCI.
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Affiliation(s)
- Joshua F Yarrow
- 1 VA Medical Center, Research Service, VA Medical Center , Gainesville, Florida
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Borst SE, Shuster JJ, Zou B, Ye F, Jia H, Wokhlu A, Yarrow JF. Cardiovascular risks and elevation of serum DHT vary by route of testosterone administration: a systematic review and meta-analysis. BMC Med 2014; 12:211. [PMID: 25428524 PMCID: PMC4245724 DOI: 10.1186/s12916-014-0211-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Potential cardiovascular (CV) risks of testosterone replacement therapy (TRT) are currently a topic of intense interest. However, no studies have addressed CV risk as a function of the route of administration of TRT. METHODS Two meta-analyses were conducted, one of CV adverse events (AEs) in 35 randomized controlled trials (RCTs) of TRT lasting 12 weeks or more, and one of 32 studies reporting the effect of TRT on serum testosterone and dihydrotestosterone (DHT). RESULTS CV risks of TRT: Of 2,313 studies identified, 35 were eligible and included 3,703 mostly older men who experienced 218 CV-related AEs. No significant risk for CV AEs was present when all TRT administration routes were grouped (relative risk (RR) = 1.28, 95% confidence interval (CI): 0.76 to 2.13, P = 0.34). When analyzed separately, oral TRT produced significant CV risk (RR = 2.20, 95% CI: 1.45 to 3.55, P = 0.015), while neither intramuscular (RR = 0.66, 95% CI: 0.28 to 1.56, P = 0.32) nor transdermal (gel or patch) TRT (RR = 1.27, 95% CI: 0.62 to 2.62, P = 0.48) significantly altered CV risk. Serum testosterone/DHT following TRT: Of 419 studies identified, 32 were eligible which included 1,152 men receiving TRT. No significant difference in the elevation of serum testosterone was present between intramuscular or transdermal TRT. However, transdermal TRT elevated serum DHT (5.46-fold, 95% CI: 4.51 to 6.60) to a greater magnitude than intramuscular TRT (2.20-fold, 95% CI: 1.74 to 2.77). CONCLUSIONS Oral TRT produces significant CV risk. While no significant effects on CV risk were observed with either injected or transdermal TRT, the point estimates suggest that further research is needed to establish whether administration by these routes is protective or detrimental, respectively. Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route, as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies.
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Affiliation(s)
- Stephen E Borst
- Geriatric Research, Education and Clinical Center, Malcom Randall VA Medical Center, 1601 SW Archer RD, Gainesville 32605-1197, FL, USA.
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21
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Beck DT, Yarrow JF, Beggs LA, Otzel DM, Ye F, Conover CF, Miller JR, Balaez A, Combs SM, Leeper AM, Williams AA, Lachacz SA, Zheng N, Wronski TJ, Borst SE. Influence of aromatase inhibition on the bone-protective effects of testosterone. J Bone Miner Res 2014; 29:2405-13. [PMID: 24764121 PMCID: PMC8366408 DOI: 10.1002/jbmr.2265] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/09/2014] [Accepted: 04/22/2014] [Indexed: 11/07/2022]
Abstract
The influence of the aromatase enzyme in androgen-induced bone maintenance after skeletal maturity remains somewhat unclear. Our purpose was to determine whether aromatase activity is essential to androgen-induced bone maintenance. Ten-month-old male Fisher 344 rats (n = 73) were randomly assigned to receive Sham surgery, orchiectomy (ORX), ORX + anastrozole (AN; aromatase inhibitor), ORX + testosterone-enanthate (TE, 7.0 mg/wk), ORX + TE + AN, ORX + trenbolone-enanthate (TREN; nonaromatizable, nonestrogenic testosterone analogue; 1.0 mg/wk), or ORX + TREN + AN. ORX animals exhibited histomorphometric indices of high-turnover osteopenia and reduced cancellous bone volume compared with Shams. Both TE and TREN administration suppressed cancellous bone turnover similarly and fully prevented ORX-induced cancellous bone loss. TE- and TREN-treated animals also exhibited greater femoral neck shear strength than ORX animals. AN co-administration slightly inhibited the suppression of bone resorption in TE-treated animals but did not alter TE-induced suppression of bone formation or the osteogenic effects of this androgen. In TREN-treated animals, AN co-administration produced no discernible effects on cancellous bone turnover or bone volume. ORX animals also exhibited reduced levator ani/bulbocavernosus (LABC) muscle mass and elevated visceral adiposity. In contrast, TE and TREN produced potent myotrophic effects in the LABC muscle and maintained fat mass at the level of Shams. AN co-administration did not alter androgen-induced effects on muscle or fat. In conclusion, androgens are able to induce direct effects on musculoskeletal and adipose tissue, independent of aromatase activity.
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Affiliation(s)
- Darren T Beck
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA; Department of Kinesiology, University of Rhode Island, Kingston, RI, USA
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22
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Yarrow JF, Ye F, Balaez A, Mantione JM, Otzel DM, Chen C, Beggs LA, Baligand C, Keener JE, Lim W, Vohra RS, Batra A, Borst SE, Bose PK, Thompson FJ, Vandenborne K. Bone loss in a new rodent model combining spinal cord injury and cast immobilization. J Musculoskelet Neuronal Interact 2014; 14:255-266. [PMID: 25198220 PMCID: PMC8349504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVES Characterize bone loss in our newly developed severe contusion spinal cord injury (SCI) plus hindlimb immobilization (IMM) model and determine the influence of muscle contractility on skeletal integrity after SCI. METHODS Female Sprague-Dawley rats were randomized to: (a) intact controls, (b) severe contusion SCI euthanized at Day 7 (SCI-7) or (c) Day 21 (SCI-21), (d) 14 days IMM-alone, (e) SCI+IMM, or (f) SCI+IMM plus 14 days body weight supported treadmill exercise (SCI+IMM+TM). RESULTS SCI-7 and SCI-21 exhibited a >20% reduction in cancellous volumetric bone mineral density (vBMD) in the hindlimbs (p⋜0.01), characterized by reductions in cancellous bone volume (cBV/TV%), trabecular number (Tb.N), and trabecular thickness. IMM-alone induced no observable bone loss. SCI+IMM exacerbated cancellous vBMD deficits with values being >45% below Controls (p⋜0.01) resulting from reduced cBV/TV% and Tb.N. SCI+IMM also produced the greatest cortical bone loss with distal femoral cortical area and cortical thickness being 14-28% below Controls (p⋜0.01) and bone strength being 37% below Controls (p⋜0.01). SCI+IMM+TM partially alleviated bone deficits, but values remained below Controls. CONCLUSIONS Residual and/or facilitated muscle contractility ameliorate bone decrements after severe SCI. Our novel SCI+IMM model represents a clinically-relevant means of assessing strategies to prevent SCI-induced skeletal deficits.
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Affiliation(s)
- J F Yarrow
- Research Service, Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, United States, 32608
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23
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Ye F, McCoy SC, Ross HH, Bernardo JA, Beharry AW, Senf SM, Judge AR, Beck DT, Conover CF, Cannady DF, Smith BK, Yarrow JF, Borst SE. Transcriptional regulation of myotrophic actions by testosterone and trenbolone on androgen-responsive muscle. Steroids 2014; 87:59-66. [PMID: 24928725 PMCID: PMC8396102 DOI: 10.1016/j.steroids.2014.05.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 12/31/2022]
Abstract
Androgens regulate body composition and skeletal muscle mass in males, but the molecular mechanisms are not fully understood. Recently, we demonstrated that trenbolone (a potent synthetic testosterone analogue that is not a substrate for 5-alpha reductase or for aromatase) induces myotrophic effects in skeletal muscle without causing prostate enlargement, which is in contrast to the known prostate enlarging effects of testosterone. These previous results suggest that the 5α-reduction of testosterone is not required for myotrophic action. We now report differential gene expression in response to testosterone versus trenbolone in the highly androgen-sensitive levator ani/bulbocavernosus (LABC) muscle complex of the adult rat after 6weeks of orchiectomy (ORX), using real time PCR. The ORX-induced expression of atrogenes (Muscle RING-finger protein-1 [MuRF1] and atrogin-1) was suppressed by both androgens, with trenbolone producing a greater suppression of atrogin-1 mRNA compared to testosterone. Both androgens elevated expression of anabolic genes (insulin-like growth factor-1 and mechano-growth factor) after ORX. ORX-induced increases in expression of glucocorticoid receptor (GR) mRNA were suppressed by trenbolone treatment, but not testosterone. In ORX animals, testosterone promoted WNT1-inducible-signaling pathway protein 2 (WISP-2) gene expression while trenbolone did not. Testosterone and trenbolone equally enhanced muscle regeneration as shown by increases in LABC mass and in protein expression of embryonic myosin by western blotting. In addition, testosterone increased WISP-2 protein levels. Together, these findings identify specific mechanisms by which testosterone and trenbolone may regulate skeletal muscle maintenance and growth.
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Affiliation(s)
- Fan Ye
- Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, FL, United States; Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, United States.
| | - Sean C McCoy
- Rural Health, VA Medical Center, Gainesville, FL, United States; Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Heather H Ross
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Joseph A Bernardo
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Adam W Beharry
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Sarah M Senf
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Andrew R Judge
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Darren T Beck
- Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, FL, United States
| | - Christine F Conover
- Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, FL, United States
| | - Darryl F Cannady
- Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, FL, United States
| | - Barbara K Smith
- Physical Therapy, University of Florida, Gainesville, FL, United States
| | - Joshua F Yarrow
- Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, United States; Research, VA Medical Center, Gainesville, FL, United States
| | - Stephen E Borst
- Geriatric Research, Education and Clinical Center, VA Medical Center, Gainesville, FL, United States; Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, United States
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Beggs LA, Yarrow JF, Conover CF, Meuleman JR, Beck DT, Morrow M, Zou B, Shuster JJ, Borst SE. Testosterone alters iron metabolism and stimulates red blood cell production independently of dihydrotestosterone. Am J Physiol Endocrinol Metab 2014; 307:E456-61. [PMID: 25074984 PMCID: PMC4154071 DOI: 10.1152/ajpendo.00184.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Testosterone (T) stimulates erythropoiesis and regulates iron homeostasis. However, it remains unknown whether the (type II) 5α-reduction of T to dihydrotestosterone (DHT) mediates these androgenic effects, as it does in some other tissues. Our purpose was to determine whether inhibition of type II 5α-reductase (via finasteride) alters red blood cell (RBC) production and serum markers of iron homeostasis subsequent to testosterone-enanthate (TE) administration in older hypogonadal men. Sixty men aged ≥60 yr with serum T <300 ng/dl or bioavailable T <70 ng/dl received treatment with TE (125 mg/wk) vs. vehicle paired with finasteride (5 mg/day) vs. placebo using a 2 × 2 factorial design. Over the course of 12 mo, TE increased RBC count 9%, hematocrit 4%, and hemoglobin 8% while suppressing serum hepcidin 57% (P < 0.001 for all measurements). Most of the aforementioned changes occurred in the first 3 mo of treatment, and finasteride coadministration did not significantly alter any of these effects. TE also reduced serum ferritin 32% (P = 0.002) within 3 mo of treatment initiation without altering iron, transferrin, or transferrin saturation. We conclude that TE stimulates erythropoiesis and alters iron homeostasis independently of the type II 5α-reductase enzyme. These results demonstrate that elevated DHT is not required for androgen-mediated erythropoiesis or for alterations in iron homeostasis that would appear to support iron incorporation into RBCs.
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Affiliation(s)
- Luke A Beggs
- Research Service, Departments of Applied Physiology and Kinesiology
| | - Joshua F Yarrow
- Research Service, Departments of Applied Physiology and Kinesiology
| | | | | | - Darren T Beck
- Department of Kinesiology, University of Rhode Island, Kingston, Rhode Island
| | - Matthew Morrow
- Research Pharmacy, Malcom Randall Veterans Affairs Medical Center, University of Florida, Gainesville, Florida
| | | | - Jonathan J Shuster
- Health Outcomes and Policy, University of Florida, Gainesville, Florida; and
| | - Stephen E Borst
- Geriatric Research, Education, and Clinical Center, and Departments of Applied Physiology and Kinesiology,
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Borst SE, Yarrow JF, Fernandez C, Conover CF, Ye F, Meuleman JR, Morrow M, Zou B, Shuster JJ. Cognitive effects of testosterone and finasteride administration in older hypogonadal men. Clin Interv Aging 2014; 9:1327-33. [PMID: 25143719 PMCID: PMC4136953 DOI: 10.2147/cia.s61760] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Serum concentrations of neuroactive androgens decline in older men and, in some studies, low testosterone is associated with decreased cognitive function and incidence of depression. Existing studies evaluating the effect of testosterone administration on cognition in older men have been largely inconclusive, with some studies reporting minor to moderate cognitive benefit, while others indicate no cognitive effect. Our objective was to assess the cognitive effects of treating older hypogonadal men for 1 year with a supraphysiological dose of testosterone, either alone or in combination with finasteride (a type II 5α-reductase inhibitor), in order to determine whether testosterone produces cognitive benefit and whether suppressed dihydrotestosterone influences cognition. Sixty men aged ≥60 years with a serum testosterone concentration of ≤300 ng/dL or bioavailable testosterone ≤70 ng/dL and no evidence of cognitive impairment received testosterone-enanthate (125 mg/week) versus vehicle, paired with finasteride (5 mg/day) versus placebo using a 2×2 factorial design. Testosterone caused a small decrease in depressive symptoms as assessed by the Geriatric Depression Scale and a moderate increase in visuospatial memory as assessed by performance on a recall trial of the Rey-Osterrieth Complex Figure Test. Finasteride caused a small increase in performance on the Benton Judgment of Line Orientation test. In total, major improvements in cognition were not observed either with testosterone or finasteride. Further studies are warranted to determine if testosterone replacement may improve cognition in other domains.
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Affiliation(s)
- Stephen E Borst
- Geriatric Research, Education and Clinical Center, Gainesville Florida
| | - Joshua F Yarrow
- Research Service, Malcom Randall VA Medical Center, Gainesville Florida
| | - Carmen Fernandez
- Geriatric Research, Education and Clinical Center, Gainesville Florida
| | | | - Fan Ye
- Research Service, Malcom Randall VA Medical Center, Gainesville Florida
| | - John R Meuleman
- Geriatric Research, Education and Clinical Center, Gainesville Florida
| | - Matthew Morrow
- Pharmacy Service, Malcom Randall VA Medical Center, Gainesville Florida
| | - Baiming Zou
- Department of Biostatistics, University of Florida, Gainesville, FL, USA
| | - Jonathan J Shuster
- Department of Health Outcomes and Policy, University of Florida, Gainesville, FL, USA
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Borst SE, Yarrow JF, Conover CF, Nseyo U, Meuleman JR, Lipinska JA, Braith RW, Beck DT, Martin JS, Morrow M, Roessner S, Beggs LA, McCoy SC, Cannady DF, Shuster JJ. Musculoskeletal and Prostate Effects of Combined Testosterone and Finasteride Administration in Older Hypogonadal Men. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494500.80104.8a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ye F, McCoy SC, Ross HH, Bernardo JA, Beharry AW, Senf SM, Judge AR, Beck DT, Conover CF, Cannady DF, Smith BK, Yarrow JF, Borst SE. Transcriptional Regulation Of Myotrophic Actions By Testosterone And Trenbolone On Androgen-responsive Muscle. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494501.87727.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Yarrow JF, Beggs LA, Conover CF, Meuleman JR, Beck DT, Morrow M, Borst SE. Testosterone Stimulates Red Blood Cell Production Independent of Dihydrotestosterone. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494378.64565.2c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Balaez A, Ye F, Baligand C, Borst SE, Keener JE, Lim W, Vohra RS, Pose PK, Vandenborne K, Yarrow JF. Cancellous Bone Loss in A New Atrophy Model Combining Spinal Cord Injury and Cast Immobilization. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000493310.39438.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Conover CF, Yarrow JF, Ye F, Cannady DF, Miller J, Shuster JJ, Borst SE. Incidence Of Low Testosterone In A Veteran Population. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494897.66338.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Otzel DM, Conover CF, Beggs LA, Beck DT, Baelez A, Combs SM, Miller JR, Ye F, Aguirre JI, Neuville KG, Williams AA, Conrad BP, Gregory CM, Wronski TJ, Bose PK, Borst SE, Yarrow JF. Testosterone Dose-Dependently Prevents Bone and Muscle Loss in Rodents Following Spinal Cord Injury. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494502.87727.eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Borst SE, Yarrow JF, Conover CF, Nseyo U, Meuleman JR, Lipinska JA, Braith RW, Beck DT, Martin JS, Morrow M, Roessner S, Beggs LA, McCoy SC, Cannady DF, Shuster JJ. Musculoskeletal and prostate effects of combined testosterone and finasteride administration in older hypogonadal men: a randomized, controlled trial. Am J Physiol Endocrinol Metab 2014; 306:E433-42. [PMID: 24326421 PMCID: PMC4073894 DOI: 10.1152/ajpendo.00592.2013] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Testosterone acts directly at androgen receptors and also exerts potent actions following 5α-reduction to dihydrotestosterone (DHT). Finasteride (type II 5α-reductase inhibitor) lowers DHT and is used to treat benign prostatic hyperplasia. However, it is unknown whether elevated DHT mediates either beneficial musculoskeletal effects or prostate enlargement resulting from higher-than-replacement doses of testosterone. Our purpose was to determine whether administration of testosterone plus finasteride to older hypogonadal men could produce musculoskeletal benefits without prostate enlargement. Sixty men aged ≥60 yr with a serum testosterone concentration of ≤300 ng/dl or bioavailable testosterone ≤70 ng/dl received 52 wk of treatment with testosterone enanthate (TE; 125 mg/wk) vs. vehicle, paired with finasteride (5 mg/day) vs. placebo using a 2 × 2 factorial design. Over the course of 12 mo, TE increased upper and lower body muscle strength by 8-14% (P = 0.015 to <0.001), fat-free mass 4.04 kg (P = 0.032), lumbar spine bone mineral density (BMD) 4.19% (P < 0.001), and total hip BMD 1.96% (P = 0.024) while reducing total body fat -3.87 kg (P < 0.001) and trunk fat -1.88 kg (P = 0.0051). In the first 3 mo, testosterone increased hematocrit 4.13% (P < 0.001). Coadministration of finasteride did not alter any of these effects. Over 12 mo, testosterone also increased prostate volume 11.4 cm(3) (P = 0.0051), an effect that was completely prevented by finasteride (P = 0.0027). We conclude that a higher-than-replacement TE combined with finasteride significantly increases muscle strength and BMD and reduces body fat without causing prostate enlargement. These results demonstrate that elevated DHT mediates testosterone-induced prostate enlargement but is not required for benefits in musculoskeletal or adipose tissue.
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Affiliation(s)
- Stephen E Borst
- Geriatric Research, Education and Clinical Center, Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
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Yarrow JF, Beck DT, Conover CF, Beggs LA, Goldberger BA, Borst SE. Invalidation of a commercially available human 5α-dihydrotestosterone immunoassay. Steroids 2013; 78:1220-5. [PMID: 24012740 PMCID: PMC8358983 DOI: 10.1016/j.steroids.2013.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/17/2013] [Accepted: 08/28/2013] [Indexed: 11/17/2022]
Abstract
Enzyme immunoassays (EIA) are commonly utilized for the evaluation of androgens in biological fluids; however, careful consideration must be given to cross-reactivity with other endogenous sex-steroid hormones. Our purpose was to determine the validity of a commonly-utilized commercially-available dihydrotestosterone (DHT) EIA. Serum samples obtained from older hypogonadal men who participated in a 12-month randomized controlled trial evaluating the effects of testosterone-enanthate (125 mg/week) or vehicle in combination with finasteride (5mg/day) or placebo were assayed for DHT via EIA and using a validated gold-standard LC-MS/MS approach. Additionally, commercially-available (DHT-free) buffer containing graded testosterone doses was evaluated by DHT immunoassay. DHT concentrations measured via EIA were 79% to >1000% higher than values obtained by LC-MS/MS (p<0.05), with the largest differences (415-1128%) occuring in groups receiving finasteride. Both LC-MS/MS and EIA indicated that testosterone-enanthate increased serum DHT to a similar magnitude. In contrast, finasteride-induced reductions in DHT were detected by LC-MS/MS, but not EIA (p<0.05). No significant associations were present for DHT concentrations between measurement techniques. Cross-reactivity of testosterone with the immunoassay ranged from 18% to 99% and DHT concentrations measured by EIA were highly associated with the spiked testosterone concentrations in DHT-free buffer (r=0.885, p<0.001). In conclusion, we provide evidence invalidating a commonly-utilized commercially-available DHT immunoassay because significant cross-reactivity exists between testosterone and the EIA and because the changes in DHT observed via EIA were not associated with a validated gold-standard measurement technique. The cross-reactivity of testosterone is particularly concerning because testsoterone is present in 100-fold greater concentrations than is DHT within the circulation.
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Affiliation(s)
- Joshua F Yarrow
- VA Medical Center, Gainesville, FL 32608, United States; Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, United States.
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Marzetti E, Calvani R, DuPree J, Lees HA, Giovannini S, Seo DO, Buford TW, Sweet K, Morgan D, Strehler KYE, Diz D, Borst SE, Moningka N, Krotova K, Carter CS. Late-life enalapril administration induces nitric oxide-dependent and independent metabolic adaptations in the rat skeletal muscle. Age (Dordr) 2013; 35:1061-75. [PMID: 22639176 PMCID: PMC3705103 DOI: 10.1007/s11357-012-9428-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 05/09/2012] [Indexed: 05/29/2023]
Abstract
Recently, we showed that administration of the angiotensin-converting enzyme inhibitor enalapril to aged rats attenuated muscle strength decline and mitigated apoptosis in the gastrocnemius muscle. The aim of the present study was to investigate possible mechanisms underlying the muscle-protective effects of enalapril. We also sought to discern the effects of enalapril mediated by nitric oxide (NO) from those independent of this signaling molecule. Eighty-seven male Fischer 344 × Brown Norway rats were randomly assigned to receive enalapril (n = 23), the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; n = 22), enalapril + L-NAME (n = 19), or placebo (n = 23) from 24 to 27 months of age. Experiments were performed on the tibialis anterior muscle. Total NOS activity and the expression of neuronal, endothelial, and inducible NOS isoforms (nNOS, eNOS, and iNOS) were determined to investigate the effects of enalapril on NO signaling. Transcript levels of tumor necrosis factor-alpha (TNF-α) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) were assessed to explore actions of enalapril on inflammation and mitochondrial biogenesis, respectively. Protein expression of energy-sensing and insulin signaling mediators, including protein kinase B (Akt-1), phosphorylated Akt-1 (pAkt-1), mammalian target of rapamycin (mTOR), AMP-activated protein kinase subunit alpha (AMPKα), phosphorylated AMPKα (pAMPKα), and the glucose transporter GLUT-4, was also determined. Finally, the generation of hydrogen peroxide (H2O2) was quantified in subsarcolemmal (SSM) and intermyofibrillar (IFM) mitochondria. Enalapril increased total NOS activity, which was prevented by L-NAME co-administration. eNOS protein content was enhanced by enalapril, but not by enalapril + L-NAME. Gene expression of iNOS was down-regulated by enalapril either alone or in combination with L-NAME. In contrast, protein levels of nNOS were unaltered by treatments. The mRNA abundance of TNF-α was reduced by enalapril relative to placebo, with no differences among any other group. PCG-1α gene expression was unaffected by enalapril and lowered by enalapril + L-NAME. No differences in protein expression of Akt-1, pAkt-1, AMPKα, pAMPKα, or GLUT-4 were detected among groups. However, mTOR protein levels were increased by enalapril compared with placebo. Finally, all treatment groups displayed reduced SSM, but not IFM H2O2 production relative to placebo. Our data indicate that enalapril induces a number of metabolic adaptations in aged skeletal muscle. These effects result from the concerted modulation of NO and angiotensin II signaling, rather than from a dichotomous action of enalapril on the two pathways. Muscle protection by enalapril administered late in life appears to be primarily mediated by mitigation of oxidative stress and pro-inflammatory signaling.
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Affiliation(s)
- Emanuele Marzetti
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
- />Department of Geriatrics, Neurology and Orthopedics, Catholic University of the Sacred Heart, Rome, 00168 Italy
| | - Riccardo Calvani
- />Department of Geriatrics, Neurology and Orthopedics, Catholic University of the Sacred Heart, Rome, 00168 Italy
- />Institute of Crystallography, National Research Council (CNR), Bari, 70126 Italy
| | - Jameson DuPree
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
| | - Hazel A. Lees
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
| | - Silvia Giovannini
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
- />Department of Geriatrics, Neurology and Orthopedics, Catholic University of the Sacred Heart, Rome, 00168 Italy
| | - Dong-oh Seo
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
| | - Thomas W. Buford
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
| | - Kindal Sweet
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
| | - Drake Morgan
- />Department of Psychiatry, University of Florida, Gainesville, FL 32610 USA
| | - Kevin Y. E. Strehler
- />Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610 USA
| | - Debra Diz
- />Department of General Surgery, Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC USA
| | - Stephen E. Borst
- />Department of Applied Kinesiology and VA Medical Center Geriatric Research, Education and Clinical Center, University of Florida, Gainesville, FL 32608 USA
| | - Natasha Moningka
- />Department of Physiology and Functional Genomics, University of Florida’s Hypertension Center, Gainesville, FL 32610 USA
| | - Karina Krotova
- />Department of Medicine, University of Florida, Gainesville, FL 32610 USA
| | - Christy S. Carter
- />Department of Aging and Geriatric Research, Institute on Aging, University of Florida, PO Box 100143, Gainesville, FL 32610-0143 USA
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Ye F, McCoy SC, Yarrow JF, Conover CF, Beck DT, Beggs LA, Beharry AW, Judge AR, Ross HH, Borsa PA, Tillman MD, Conrad BP, Pingel JE, Wronski TJ, Johnson SE, Kristinsson HG, Borst SE. Effect of Trenbolone enanthate on protein degradation in levator ani/bulbocavernosus (LABC) muscle in orchiectomized rats. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.939.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fan Ye
- GeriatricsVA Medical CenterGainesvilleFL
| | | | | | | | | | - Luke A Beggs
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | | | | | | | - Paul A Borsa
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | - Mark D Tillman
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | - Bryan P Conrad
- Orthopedics & RehabilitationUniversity of FloridaGainesvilleFL
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Beggs LA, Beck DT, Conover CF, Ye F, Combs SM, Miller JR, Balaez A, Neuville KG, Wronski TJ, Bose P, Borst SE, Yarrow JF. Testosterone treatment prevents spinal cord injury‐induced bone loss in male rats. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.941.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luke Allen Beggs
- Malcom Randall VA Medical CenterGainesvilleFL
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | | | | | - Fan Ye
- Malcom Randall VA Medical CenterGainesvilleFL
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | | | | | - Alexander Balaez
- Malcom Randall VA Medical CenterGainesvilleFL
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | | | | | - Prodip Bose
- Malcom Randall VA Medical CenterGainesvilleFL
- Physiological SciencesUniversity of FloridaGainesvilleFL
| | - Stephen E Borst
- Malcom Randall VA Medical CenterGainesvilleFL
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
| | - Joshua F Yarrow
- Malcom Randall VA Medical CenterGainesvilleFL
- Applied Physiology & KinesiologyUniversity of FloridaGainesvilleFL
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Beck DT, Yarrow JF, McCoy SC, Beggs LA, Ye F, Balaez A, Combs SM, Miller JR, Conover CF, Borst SE. The combined effects of Anastrozole and Testosterone or Trenbolone on Prostate and Levator Ani‐Bulbo Cavernosus Mass. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1150.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Darren Thomas Beck
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Joshua F Yarrow
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Sean C McCoy
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Luke A Beggs
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Fan Ye
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Alexander Balaez
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Sarah M Combs
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Julie R Miller
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Christine F Conover
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
| | - Stephen E Borst
- Geriatric Research Education and Clinical CentersMalcom Randall VA Medical CenterGainesvilleFL
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
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Ye F, Mathur S, Liu M, Borst SE, Walter GA, Sweeney HL, Vandenborne K. Overexpression of insulin-like growth factor-1 attenuates skeletal muscle damage and accelerates muscle regeneration and functional recovery after disuse. Exp Physiol 2013; 98:1038-52. [PMID: 23291913 DOI: 10.1113/expphysiol.2012.070722] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Skeletal muscle is a highly dynamic tissue that responds to endogenous and external stimuli, including alterations in mechanical loading and growth factors. In particular, the antigravity soleus muscle experiences significant muscle atrophy during disuse and extensive muscle damage upon reloading. Given that insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair and modulation of muscle size, we examined the effect of virally mediated overexpression of IGF-1 on the soleus muscle following hindlimb cast immobilization and upon reloading. Recombinant IGF-1 cDNA virus was injected into one of the posterior hindlimbs of the mice, while the contralateral limb was injected with saline (control). At 20 weeks of age, both hindlimbs were immobilized for 2 weeks to induce muscle atrophy in the soleus and ankle plantarflexor muscle group. Subsequently, the mice were allowed to reambulate, and muscle damage and recovery were monitored over a period of 2-21 days. The primary finding of this study was that IGF-1 overexpression attenuated reloading-induced muscle damage in the soleus muscle, and accelerated muscle regeneration and force recovery. Muscle T2 assessed by magnetic resonance imaging, a non-specific marker of muscle damage, was significantly lower in IGF-1-injected compared with contralateral soleus muscles at 2 and 5 days reambulation (P<0.05). The reduced prevalence of muscle damage in IGF-1-injected soleus muscles was confirmed on histology, with a lower fractional area of abnormal muscle tissue in IGF-1-injected muscles at 2 days reambulation (33.2±3.3 versus 54.1±3.6%, P<0.05). Evidence of the effect of IGF-1 on muscle regeneration included timely increases in the number of central nuclei (21% at 5 days reambulation), paired-box transcription factor 7 (36% at 5 days), embryonic myosin (37% at 10 days) and elevated MyoD mRNA (7-fold at 2 days) in IGF-1-injected limbs (P<0.05). These findings demonstrate a potential role of IGF-1 in protecting unloaded skeletal muscles from damage and accelerating muscle repair and regeneration.
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Affiliation(s)
- Fan Ye
- Department of Physical Therapy, PO Box 100154, Room 1142, PHHP Building, University of Florida, Gainesville, FL 32610, USA
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Yarrow JF, Beggs LA, Conover CF, McCoy SC, Beck DT, Borst SE. Influence of androgens on circulating adiponectin in male and female rodents. PLoS One 2012; 7:e47315. [PMID: 23071783 PMCID: PMC3468547 DOI: 10.1371/journal.pone.0047315] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 09/14/2012] [Indexed: 01/03/2023] Open
Abstract
Several endocrine factors, including sex-steroid hormones are known to influence adiponectin secretion. Our purpose was to evaluate the influence of testosterone and of the synthetic non-aromatizable/non-5α reducible androgen 17β-hydroxyestra-4,9,11-trien-3-one (trenbolone) on circulating adiponectin and adiponectin protein expression within visceral fat. Young male and female F344 rats underwent sham surgery (SHAM), gonadectomy (GX), or GX plus supraphysiologic testosterone-enanthate (TE) administration. Total circulating adiponectin was 39% higher in intact SHAM females than SHAM males (p<0.05). GX increased total adiponectin by 29-34% in both sexes (p<0.05), while TE reduced adiponectin to concentrations that were 46-53% below respective SHAMs (p≤0.001) and ablated the difference in adiponectin between sexes. No differences in high molecular weight (HMW) adiponectin were observed between sexes or treatments. Adiponectin concentrations were highly and negatively associated with serum testosterone (males: r = -0.746 and females: r = -0.742, p≤0.001); however, no association was present between adiponectin and estradiol. In separate experiments, trenbolone-enanthate (TREN) prevented the GX-induced increase in serum adiponectin (p≤0.001) in young animals, with Low-dose TREN restoring adiponectin to the level of SHAMs and higher doses of TREN reducing adiponectin to below SHAM concentrations (p≤0.001). Similarly, TREN reduced adiponectin protein expression within visceral fat (p<0.05). In adult GX males, Low-dose TREN also reduced total adiponectin and visceral fat mass to a similar magnitude as TE, while increasing serum HMW adiponectin above SHAM and GX animals (p<0.05). Serum adiponectin was positively associated with visceral fat mass in young (r = 0.596, p≤0.001) and adult animals (r = 0.657, p≤0.001). Our results indicate that androgens reduce circulating total adiponectin concentrations in a dose-dependent manner, while maintaining HMW adiponectin. This change is directionally similar to the androgen-induced lipolytic effects on visceral adiposity and equal in magnitude between TE and TREN, suggesting that neither the aromatization nor the 5α reduction of androgens is required for this effect.
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Affiliation(s)
- Joshua F Yarrow
- Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, USA.
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McCoy SC, Yarrow JF, Conover CF, Borsa PA, Tillman MD, Conrad BP, Pingel JE, Wronski TJ, Johnson SE, Kristinsson HG, Ye F, Borst SE. 17β-Hydroxyestra-4,9,11-trien-3-one (Trenbolone) preserves bone mineral density in skeletally mature orchiectomized rats without prostate enlargement. Bone 2012; 51:667-73. [PMID: 22842328 PMCID: PMC8392872 DOI: 10.1016/j.bone.2012.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/27/2012] [Accepted: 07/13/2012] [Indexed: 01/23/2023]
Abstract
Testosterone enanthate (TE) administration attenuates bone loss in orchiectomized (ORX) rats. However, testosterone administration may increase risk for prostate/lower urinary tract related adverse events and polycythemia in humans. Trenbolone enanthate (TREN) is a synthetic testosterone analogue that preserves bone mineral density (BMD) and results in less prostate enlargement than testosterone in young ORX rodents. The purpose of this experiment was to determine if intramuscular TREN administration attenuates bone loss and maintains bone strength, without increasing prostate mass or hemoglobin concentrations in skeletally mature ORX rodents. Forty, 10 month old male F344/Brown Norway rats were randomized into SHAM, ORX, ORX+TE (7.0mg/week), and ORX+TREN (1.0mg/week) groups. Following surgery, animals recovered for 1 week and then received weekly: vehicle, TE, or TREN intramuscularly for 5 weeks. ORX reduced total and trabecular (t) BMD at the distal femoral metaphysis compared with SHAMs, while both TREN and TE completely prevented these reductions. TREN treatment also increased femoral neck strength by 28% compared with ORX animals (p<0.05), while TE did not alter femoral neck strength. In addition, TE nearly doubled prostate mass, compared with SHAMs (p<0.05). Conversely, TREN induced a non-significant 20% reduction in prostate mass compared with SHAMs, ultimately producing a prostate mass that was 64% below that found in ORX+TE animals (p<0.01). Hemoglobin concentrations and levator ani/bulbocavernosus (LABC) muscle mass were elevated in ORX+TE and ORX+TREN animals to a similar degree above both SHAM and ORX conditions (p<0.01). In skeletally mature rodents, both high-dose TE and low-dose TREN completely prevented the ORX-induced loss of tBMD at the distal femoral metaphysis and increased LABC mass. TREN also augmented femoral neck strength and maintained prostate mass at SHAM levels. These findings indicate that TREN may be an advantageous agent for future clinical trials evaluating agents capable of preventing bone loss resulting from androgen deficiency.
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Affiliation(s)
- Sean C. McCoy
- Geriatric Research, Education & Clinical Center, VA Medical Center, Gainesville, FL 32608, USA
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, USA
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Joshua F. Yarrow
- Geriatric Research, Education & Clinical Center, VA Medical Center, Gainesville, FL 32608, USA
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - Christine F. Conover
- Geriatric Research, Education & Clinical Center, VA Medical Center, Gainesville, FL 32608, USA
| | - Paul A. Borsa
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - Mark D. Tillman
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - Bryan P. Conrad
- Department of Orthopedics & Rehabilitation, University of Florida, Gainesville, FL 32611, USA
| | - Jennifer E. Pingel
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Thomas J. Wronski
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Sally E. Johnson
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
| | | | - Fan Ye
- Department of Physical Therapy, University of Florida, Gainesville, FL 32611, USA
| | - Stephen E. Borst
- Geriatric Research, Education & Clinical Center, VA Medical Center, Gainesville, FL 32608, USA
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL 32611, USA
- Corresponding author at: VA Medical Center, GRECC - 182, 1601 SW Archer Rd., Gainesville, FL 32608-1197, USA. Fax: +1 352 374 6142., (S.E. Borst)
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Manini TM, Yarrow JF, Buford TW, Clark BC, Conover CF, Borst SE. Growth hormone responses to acute resistance exercise with vascular restriction in young and old men. Growth Horm IGF Res 2012; 22:167-172. [PMID: 22727808 PMCID: PMC3915940 DOI: 10.1016/j.ghir.2012.05.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/23/2012] [Accepted: 05/24/2012] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Resistance exercise (RE) stimulates growth hormone (GH) secretion in a load-dependent manner, with heavier loads producing larger GH responses. However, new research demonstrates that low-load RE performed with blood flow restriction (BFR) produces potent GH responses that are similar to or exceed those produced following high-load RE. We hypothesized that low-load RE with vascular restriction would attenuate the known age-related reduction in GH response to RE. DESIGN In a randomized crossover design, ten young (28 ± 7.8 years) and ten older (67.4 ± 4.6 years) men performed bilateral knee extension RE with low-load [20% of one-repetition maximum (1RM)] with BFR and high-load (80% 1RM) without BFR. GH and lactate were measured every 10 minutes throughout a 150-minute testing session (30 minutes prior to and 120 minutes following completion of the exercise); IGF-I was measured at baseline and 60 minutes post-exercise. RESULTS Area under the GH curve indicated that both age groups responded similarly to each exercise condition. However, young men had a significantly greater maximal GH response to low-load RE with BFR than the high-load condition without BFR. Additionally, younger men had greater maximal GH concentrations to low-load RE with BFR than older men (p=0.02). The GH responses were marginally correlated to lactate concentration (r=0.13, p=0.002) and IGF-I levels were unchanged with RE. CONCLUSIONS GH responses to low-load RE with vascular restriction are slightly higher than high-load RE without vascular restriction in young men. However, low-load RE with vascular restriction did not attenuate the known age-related reduction in GH response with exercise. These data suggest that while low-load RE with vascular restriction is as effective for inducing a GH response than traditionally-based high-load RE, there is a more potent response in young men.
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Affiliation(s)
- Todd M Manini
- University of Florida, Department of Aging and Geriatric Research, Gainesville, USA.
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Abstract
UNLABELLED Historically, the circulation was thought to be the primary source of androgens influencing skeletal muscle. However, a growing body of research indicates that skeletal muscle expresses several androgen-synthesizing enzymes, including 5α-reductase. The intramuscular expression of these enzymes suggests that skeletal muscle is capable of synthesizing bioactive androgens, which could induce myotrophic effects via intracrine action. PURPOSE The aim of this brief review is to discuss recent research related to the intracrine and myotrophic roles of androgens, with particular focus on 5α-reductase as a myotrophic mediator. METHODS Included in the review are 17 reviews and 58 original studies that were identified by a systematic review from MEDLINE and deemed particularly relevant to our purpose. Results are summarized to provide an overview of 5α-reductase as a mediator of the myotrophic effects of androgens. In particular, discussions are included regarding androgen biosynthesis and androgen signaling within skeletal muscle, the effects of exercise on intramuscular androgen biosynthesis, and clinical applications of androgens and of a new class of myotrophic agonists termed selective androgen receptor modulator. RESULTS The ability of several peripheral tissues to synthesize bioactive androgens is well documented in the literature. Herein, we summarize newer studies that demonstrate that 1) skeletal muscle has the capability to synthesize both testosterone and dihydrotestosterone from dehydroepiandrosterone, which is present in abundance within the circulation, and 2) that exercise increases the expression of certain androgen-biosynthesizing enzymes within muscle. CONCLUSIONS Intramuscularly synthesized androgens have the potential to influence skeletal muscle via intracrine action; however, their exact role in skeletal muscle development and maintenance requires further elucidation.
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Borst SE, Yarrow JF, Conover CF, McCoy SC, Sanchez J, VanPelt TD, Cannady DF, Bose PK. Swim Test Reveals That Estriol, But Not Estrone, Preserves Memory In Ovariectomized Female Rats. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402175.24303.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yarrow JF, Brown M, McCoy SC, Conoveer CF, Pingel JE, Wronski TJ, Borst SE. Estrogen is Required for Reambulation Induced Restoration of Bone Following Hindlimb Unloading of Ovariectomized Rats. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000400691.84714.3c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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McCoy SC, Yarrow JF, Conover CF, Pingel JE, Wronski TJ, Lipinska JA, Santillana CA, Borst SE. Androgens, But Not Mechanical Loading, Attenuate Bone Loss And High-turnover Osteopenia In Orchiectomized Rats. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402999.66981.e6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yarrow JF, Conover CF, McCoy SC, Lipinska JA, Santillana CA, Hance JM, Cannady DF, VanPelt TD, Sanchez J, Conrad BP, Pingel JE, Wronski TJ, Borst SE. 17β-Hydroxyestra-4,9,11-trien-3-one (trenbolone) exhibits tissue selective anabolic activity: effects on muscle, bone, adiposity, hemoglobin, and prostate. Am J Physiol Endocrinol Metab 2011; 300:E650-60. [PMID: 21266670 PMCID: PMC6189634 DOI: 10.1152/ajpendo.00440.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Selective androgen receptor modulators (SARMs) now under development can protect against muscle and bone loss without causing prostate growth or polycythemia. 17β-Hydroxyestra-4,9,11-trien-3-one (trenbolone), a potent testosterone analog, may have SARM-like actions because, unlike testosterone, trenbolone does not undergo tissue-specific 5α-reduction to form more potent androgens. We tested the hypothesis that trenbolone-enanthate (TREN) might prevent orchiectomy-induced losses in muscle and bone and visceral fat accumulation without increasing prostate mass or resulting in adverse hemoglobin elevations. Male F344 rats aged 3 mo underwent orchiectomy or remained intact and were administered graded doses of TREN, supraphysiological testosterone-enanthate, or vehicle for 29 days. In both intact and orchiectomized animals, all TREN doses and supraphysiological testosterone-enanthate augmented androgen-sensitive levator ani/bulbocavernosus muscle mass by 35-40% above shams (P ≤ 0.001) and produced a dose-dependent partial protection against orchiectomy-induced total and trabecular bone mineral density losses (P < 0.05) and visceral fat accumulation (P < 0.05). The lowest doses of TREN successfully maintained prostate mass and hemoglobin concentrations at sham levels in both intact and orchiectomized animals, whereas supraphysiological testosterone-enanthate and high-dose TREN elevated prostate mass by 84 and 68%, respectively (P < 0.01). In summary, low-dose administration of the non-5α-reducible androgen TREN maintains prostate mass and hemoglobin concentrations near the level of shams while producing potent myotrophic actions in skeletal muscle and partial protection against orchiectomy-induced bone loss and visceral fat accumulation. Our findings indicate that TREN has advantages over supraphysiological testosterone and supports the need for future preclinical studies examining the viability of TREN as an option for androgen replacement therapy.
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Affiliation(s)
- Joshua F Yarrow
- VA Medical Center, University of Florida, Gainesville, 32608-1197, USA.
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Manini TM, Vincent KR, Leeuwenburgh CL, Lees HA, Kavazis AN, Borst SE, Clark BC. Myogenic and proteolytic mRNA expression following blood flow restricted exercise. Acta Physiol (Oxf) 2011; 201:255-63. [PMID: 20653608 DOI: 10.1111/j.1748-1716.2010.02172.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Resistance exercise performed at low loads (20-30% of maximal strength) with blood flow restriction (BFR) acutely increases protein synthesis and induces hypertrophy when performed chronically. We investigated myogenic and proteolytic mRNA expression 8 h following an acute bout of knee extension exercise. METHODS Fifteen subjects (22.8 ± 3.7 years, eight men and seven women) were randomized to two exercise conditions: BFR or control exercise. All participants performed four sets of exercise (30, 15, 15 and 15 repetitions) at 20% of maximal strength. Persons in the BFR group had a cuff placed on the upper thigh inflated to 1.5 times brachial systolic blood pressure (cuff pressure range: 135-186 mmHg). Muscle biopsies from the vastus lateralis were excised 24 h before and 8 h following the exercise. RESULTS RT-PCR analysis demonstrated no change in myogenic gene expression (insulin-like growth factor-1, MyoD, myogenin, myostatin - a negative regulator) with either exercise condition (P > 0.123). However, BFR exercise downregulated mRNA expression in transcripts associated with proteolytic pathways (FOXO3A, Atrogin-1 and MuRF-1) with no change in the control exercise condition. Specifically, median mRNA expression of FOXO3A decreased by 1.92-fold (P = 0.01), Atrogin-1 by 2.10-fold (P = 0.01) and MuRF-1 by 2.44-fold (P = 0.01). CONCLUSION These data are consistent with the downregulation of proteolytic transcripts observed following high-load resistance exercise. In summary, myogenic genes are unchanged and proteolytic genes associated with muscle remodelling are reduced 8 h following low-load BFR exercise.
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Affiliation(s)
- T M Manini
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL 32611-0107, USA.
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Stevens-Lapsley JE, Ye F, Liu M, Borst SE, Conover C, Yarasheski KE, Walter GA, Sweeney HL, Vandenborne K. Impact of viral-mediated IGF-I gene transfer on skeletal muscle following cast immobilization. Am J Physiol Endocrinol Metab 2010; 299:E730-40. [PMID: 20739512 PMCID: PMC2980362 DOI: 10.1152/ajpendo.00230.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 08/17/2010] [Indexed: 11/22/2022]
Abstract
Insulin-like growth factor I (IGF-I) is a potent myogenic factor that plays a critical role in muscle regeneration and muscle hypertrophy. The purpose of this study was to evaluate the effect of IGF-I overexpression on the recovery of muscle size and function during reloading/reambulation after a period of cast immobilization in predominantly fast twitch muscles. In addition, we investigated concomitant molecular responses in IGF-I receptor and binding proteins (BPs). Recombinant adeno-associated virus vector for IGF-I (rAAV-IGF-IA) was injected into the anterior compartment of one of the hindlimbs of young (3 wk) C57BL6 female mice. At 20 wk of age, both hindlimbs were cast immobilized in a shortened position for 2 wk to unload the tibialis anterior (TA) and extensor longus digitorum (EDL) muscles. The TA and EDL muscles were removed bilaterally after 2 wk of cast immobilization and after 1 and 3 wk of free cage reambulation. Increases in IGF-I mRNA and protein levels with IGF-I overexpression were associated with significant increases in muscle wet weight, fiber size, and tetanic force, although overexpression did not protect against cast immobilization-induced muscle atrophy. After 1 wk of reambulation, evidence of enhanced muscle regeneration was noted in IGF-I-overexpressing muscles with an increased prevalence of central nuclei, embryonic myosin, and Pax7 positive fibers. We also observed larger relative gains in muscle size (wet weight and fiber area), but not force, during the 3-wk reambulation period in hindlimb muscles overexpressing IGF-I compared with contralateral control legs. Changes in IGFBP-5 mRNA expression during cast immobilization and reambulation paralleled those of IGF-I, whereas IGFBP-3 expression changed inversely to IGFBP-5.
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Yarrow JF, Conover CF, Lipinska JA, Santillana CA, Wronski TJ, Borst SE. Methods to quantify sex steroid hormones in bone: applications to the study of androgen ablation and administration. Am J Physiol Endocrinol Metab 2010; 299:E841-7. [PMID: 20739509 DOI: 10.1152/ajpendo.00384.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bone may contain an intraskeletal reservoir of sex steroids that is capable of producing biological effects. The purposes of these experiments were to 1) establish and validate methods to extract and measure intraskeletal sex hormones, 2) compare serum and intraskeletal sex hormone abundance, and 3) determine the impact of testosterone-enanthate administration and orchiectomy on intraskeletal sex hormone concentrations. Tibiae from male F344 rats were crushed, suspended in an aqueous buffer, disrupted mechanically and sonically, extracted with organic solvents, dried, and reconstituted in assay buffer appropriate for measurement of testosterone, dihydrotestosterone, and estradiol by immunoassay. Prior to extraction, bone homogenate was spiked with [³H]testosterone, [³H]dihydrotestosterone, or [³H]estradiol, and >80% of each ³H-labeled sex hormone was recovered. Extracted bone samples were also assayed with and without known amounts of unlabeled sex hormones, and >97% of the expected hormone concentrations were measured. Administration of testosterone-enanthate increased intraskeletal testosterone 11-fold and intraskeletal dihydrotestosterone by 82% without altering intraskeletal estradiol (P < 0.01). Conversely, orchiectomy did not alter intraskeletal testosterone or estradiol but increased intraskeletal dihydrotestosterone by 39% (P < 0.05). In intact rats, intraskeletal testosterone and dihydrotestosterone were directionally higher than in serum, whereas intraskeletal estradiol was directionally lower than serum. Serum androgens were positively correlated with intraskeletal androgens (r = 0.74-0.96, P < 0.001); however, neither serum nor intraskeletal androgens nor serum estradiol were correlated with intraskeletal estradiol. We report the validation of a novel method for measuring intraskeletal sex hormones. Our findings demonstrate that the intraskeletal sex steroid reservoirs are modifiable and only partially influenced by circulating sex hormones.
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Affiliation(s)
- Joshua F Yarrow
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Gainesville, FL 32608-1197, USA
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Yarrow JF, McCoy SC, Borst SE. Tissue selectivity and potential clinical applications of trenbolone (17beta-hydroxyestra-4,9,11-trien-3-one): A potent anabolic steroid with reduced androgenic and estrogenic activity. Steroids 2010; 75:377-89. [PMID: 20138077 DOI: 10.1016/j.steroids.2010.01.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 01/21/2010] [Accepted: 01/26/2010] [Indexed: 11/24/2022]
Abstract
Recently, the development of selective androgen receptor modulators (SARMs) has been suggested as a means of combating the deleterious catabolic effects of hypogonadism, especially in skeletal muscle and bone, without inducing the undesirable androgenic effects (e.g., prostate enlargement and polycythemia) associated with testosterone administration. 17beta-Hydroxyestra-4,9,11-trien-3-one (trenbolone; 17beta-TBOH), a synthetic analog of testosterone, may be capable of inducing SARM-like effects as it binds to androgen receptors (ARs) with approximately three times the affinity of testosterone and has been shown to augment skeletal muscle mass and bone growth and reduce adiposity in a variety of mammalian species. In addition to its direct actions through ARs, 17beta-TBOH may also exert anabolic effects by altering the action of endogenous growth factors or inhibiting the action of glucocorticoids. Compared to testosterone, 17beta-TBOH appears to induce less growth in androgen-sensitive organs which highly express the 5alpha reductase enzyme (e.g., prostate tissue and accessory sex organs). The reduced androgenic effects result from the fact that 17beta-TBOH is metabolized to less potent androgens in vivo; while testosterone undergoes tissue-specific biotransformation to more potent steroids, dihydrotestosterone and 17beta-estradiol, via the 5alpha-reductase and aromatase enzymes, respectively. Thus the metabolism of 17beta-TBOH provides a basis for future research evaluating its safety and efficacy as a means of combating muscle and bone wasting conditions, obesity, and/or androgen insensitivity syndromes in humans, similar to that of other SARMs which are currently in development.
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Affiliation(s)
- Joshua F Yarrow
- Geriatric Research, Education & Clinical Center, VA Medical Center, Gainesville, FL 32608, United States.
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