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Cianferotti L, Brandi ML. Muscle-bone interactions: basic and clinical aspects. Endocrine 2014; 45:165-77. [PMID: 23990248 DOI: 10.1007/s12020-013-0026-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/25/2013] [Indexed: 12/19/2022]
Abstract
Muscle and bone are anatomically and functionally closely connected. The traditional concept that skeletal muscles serve to load bone and transform skeletal segments into a system of levers has been further refined into the mechanostat theory, according to which striated muscle is essential for bone development and maintenance, modelling and remodelling. Besides biomechanical function, skeletal muscle and bone are endocrine organs able to secrete factors capable of modulating biological function within their microenvironment, in nearby tissues or in distant organs. The endocrine properties of muscle and bone may serve to sense and transduce biomechanical signals such as loading, unloading or exercise, or systemic hormonal stimuli into biochemical signals. Nonetheless, given the close anatomical relationship between skeletal muscle and bone, paracrine interactions particularly at the periosteal interface can be hypothesized. These mechanisms can assume particular importance during bone and muscle healing after musculoskeletal injury. Basic studies in vitro and in rodents have helped to dissect the multiple influences of skeletal muscle on bone and/or expression of inside-organ metabolism and have served to explain clinical observations linking muscle-to-bone quality. Recent evidences pinpoint that also bone tissue is able to modulate directly or indirectly skeletal muscle metabolism, thus empowering the crosstalk hypothesis to be further tested in humans in vivo.
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Affiliation(s)
- Luisella Cianferotti
- Unit of Bone and Mineral Metabolism, Department of Surgery and Translational Medicine, Section of Endocrinology and Metabolism, School of Human Health Sciences, University of Florence, Viale Pieraccini, 6, 50139, Florence, Italy
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Prior S, Kim A, Yoshihara T, Tobita S, Takeuchi T, Higuchi M. Mitochondrial respiratory function induces endogenous hypoxia. PLoS One 2014; 9:e88911. [PMID: 24586439 PMCID: PMC3931703 DOI: 10.1371/journal.pone.0088911] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 01/17/2014] [Indexed: 01/26/2023] Open
Abstract
Hypoxia influences many key biological functions. In cancer, it is generally believed that hypoxic condition is generated deep inside the tumor because of the lack of oxygen supply. However, consumption of oxygen by cancer should be one of the key means of regulating oxygen concentration to induce hypoxia but has not been well studied. Here, we provide direct evidence of the mitochondrial role in the induction of intracellular hypoxia. We used Acetylacetonatobis [2-(2′-benzothienyl) pyridinato-kN, kC3’] iridium (III) (BTP), a novel oxygen sensor, to detect intracellular hypoxia in living cells via microscopy. The well-differentiated cancer cell lines, LNCaP and MCF-7, showed intracellular hypoxia without exogenous hypoxia in an open environment. This may be caused by high oxygen consumption, low oxygen diffusion in water, and low oxygen incorporation to the cells. In contrast, the poorly-differentiated cancer cell lines: PC-3 and MDAMB231 exhibited intracellular normoxia by low oxygen consumption. The specific complex I inhibitor, rotenone, and the reduction of mitochondrial DNA (mtDNA) content reduced intracellular hypoxia, indicating that intracellular oxygen concentration is regulated by the consumption of oxygen by mitochondria. HIF-1α was activated in endogenously hypoxic LNCaP and the activation was dependent on mitochondrial respiratory function. Intracellular hypoxic status is regulated by glucose by parabolic dose response. The low concentration of glucose (0.045 mg/ml) induced strongest intracellular hypoxia possibly because of the Crabtree effect. Addition of FCS to the media induced intracellular hypoxia in LNCaP, and this effect was partially mimicked by an androgen analog, R1881, and inhibited by the anti-androgen, flutamide. These results indicate that mitochondrial respiratory function determines intracellular hypoxic status and may regulate oxygen-dependent biological functions.
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Affiliation(s)
- Sara Prior
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Ara Kim
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Toshitada Yoshihara
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, University of Gunma, Kiryu, Gunma, Japan
| | - Seiji Tobita
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, University of Gunma, Kiryu, Gunma, Japan
| | - Toshiyuki Takeuchi
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, University of Gunma, Maebashi, Gunma, Japan
| | - Masahiro Higuchi
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail:
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Quillinan N, Deng G, Grewal H, Herson PS. Androgens and stroke: good, bad or indifferent? Exp Neurol 2014; 259:10-5. [PMID: 24512750 DOI: 10.1016/j.expneurol.2014.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/28/2014] [Accepted: 02/02/2014] [Indexed: 12/16/2022]
Abstract
Cerebral ischemia caused by loss of blood supply to the brain during cardiac arrest or stroke are major causes of death and disability. Biological sex is an important factor in predicting vulnerability of the brain to an ischemic insult, with males being at higher risk for cardio-cerebrovascular events than females of the same age. However, relative incidence of stroke between the genders appears to normalize at advanced ages. Therefore, many scientists have focused on the mechanisms of sex differences in outcome following brain ischemic injury, with a particular emphasis on the role of sex steroids. The majority of studies indicate that female sex steroids, such as estrogen and progesterone, play important roles in the relative neuroprotection following cerebral ischemia observed in females. However, less is known about male sex steroids and brain damage. This review describes the state of our knowledge of androgen-related contributions to neurological injury and recovery following cerebral ischemia that occurs following stroke. Experimental studies examining the effects of castration, androgenic agonists and antagonists and aging provide valuable insights into the role of androgens in clinical outcome following cerebrovascular events.
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Affiliation(s)
- Nidia Quillinan
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, USA
| | - Guiying Deng
- Department of Pharmacology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, USA
| | - Himmat Grewal
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, USA; Department of Pharmacology, University of Colorado Denver, Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, USA.
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104
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Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLoS One 2014. [PMID: 24489673 DOI: 10.1371/journal.pone.0085805.] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND An association between testosterone therapy (TT) and cardiovascular disease has been reported and TT use is increasing rapidly. METHODS We conducted a cohort study of the risk of acute non-fatal myocardial infarction (MI) following an initial TT prescription (N = 55,593) in a large health-care database. We compared the incidence rate of MI in the 90 days following the initial prescription (post-prescription interval) with the rate in the one year prior to the initial prescription (pre-prescription interval) (post/pre). We also compared post/pre rates in a cohort of men prescribed phosphodiesterase type 5 inhibitors (PDE5I; sildenafil or tadalafil, N = 167,279), and compared TT prescription post/pre rates with the PDE5I post/pre rates, adjusting for potential confounders using doubly robust estimation. RESULTS In all subjects, the post/pre-prescription rate ratio (RR) for TT prescription was 1.36 (1.03, 1.81). In men aged 65 years and older, the RR was 2.19 (1.27, 3.77) for TT prescription and 1.15 (0.83, 1.59) for PDE5I, and the ratio of the rate ratios (RRR) for TT prescription relative to PDE5I was 1.90 (1.04, 3.49). The RR for TT prescription increased with age from 0.95 (0.54, 1.67) for men under age 55 years to 3.43 (1.54, 7.56) for those aged ≥ 75 years (p trend = 0.03), while no trend was seen for PDE5I (p trend = 0.18). In men under age 65 years, excess risk was confined to those with a prior history of heart disease, with RRs of 2.90 (1.49, 5.62) for TT prescription and 1.40 (0.91, 2.14) for PDE5I, and a RRR of 2.07 (1.05, 4.11). DISCUSSION In older men, and in younger men with pre-existing diagnosed heart disease, the risk of MI following initiation of TT prescription is substantially increased.
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105
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Finkle WD, Greenland S, Ridgeway GK, Adams JL, Frasco MA, Cook MB, Fraumeni JF, Hoover RN. Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLoS One 2014; 9:e85805. [PMID: 24489673 PMCID: PMC3905977 DOI: 10.1371/journal.pone.0085805] [Citation(s) in RCA: 503] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/02/2013] [Indexed: 12/16/2022] Open
Abstract
Background An association between testosterone therapy (TT) and cardiovascular disease has been reported and TT use is increasing rapidly. Methods We conducted a cohort study of the risk of acute non-fatal myocardial infarction (MI) following an initial TT prescription (N = 55,593) in a large health-care database. We compared the incidence rate of MI in the 90 days following the initial prescription (post-prescription interval) with the rate in the one year prior to the initial prescription (pre-prescription interval) (post/pre). We also compared post/pre rates in a cohort of men prescribed phosphodiesterase type 5 inhibitors (PDE5I; sildenafil or tadalafil, N = 167,279), and compared TT prescription post/pre rates with the PDE5I post/pre rates, adjusting for potential confounders using doubly robust estimation. Results In all subjects, the post/pre-prescription rate ratio (RR) for TT prescription was 1.36 (1.03, 1.81). In men aged 65 years and older, the RR was 2.19 (1.27, 3.77) for TT prescription and 1.15 (0.83, 1.59) for PDE5I, and the ratio of the rate ratios (RRR) for TT prescription relative to PDE5I was 1.90 (1.04, 3.49). The RR for TT prescription increased with age from 0.95 (0.54, 1.67) for men under age 55 years to 3.43 (1.54, 7.56) for those aged ≥75 years (ptrend = 0.03), while no trend was seen for PDE5I (ptrend = 0.18). In men under age 65 years, excess risk was confined to those with a prior history of heart disease, with RRs of 2.90 (1.49, 5.62) for TT prescription and 1.40 (0.91, 2.14) for PDE5I, and a RRR of 2.07 (1.05, 4.11). Discussion In older men, and in younger men with pre-existing diagnosed heart disease, the risk of MI following initiation of TT prescription is substantially increased.
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Affiliation(s)
- William D. Finkle
- Consolidated Research, Inc., Los Angeles, California, United States of America
- * E-mail: (RNH); (WDF)
| | - Sander Greenland
- Department of Epidemiology and Department of Statistics, University of California, Los Angeles, California, United States of America
| | - Gregory K. Ridgeway
- Consolidated Research, Inc., Los Angeles, California, United States of America
| | - John L. Adams
- Consolidated Research, Inc., Los Angeles, California, United States of America
| | - Melissa A. Frasco
- Consolidated Research, Inc., Los Angeles, California, United States of America
| | - Michael B. Cook
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Joseph F. Fraumeni
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Robert N. Hoover
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail: (RNH); (WDF)
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Sattler F, He J, Chukwuneke J, Kim H, Stewart Y, Colletti P, Yarasheski K, Buchanan T. Testosterone Supplementation Improves Carbohydrate and Lipid Metabolism in Some Older Men with Abdominal Obesity. ACTA ACUST UNITED AC 2014; 3:1000159. [PMID: 25392748 PMCID: PMC4225803 DOI: 10.4172/2167-7182.1000159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background/Objectives The effects of testosterone supplementation on carbohydrate and lipid metabolism in obese older men are uncertain. We conducted a single-arm open-label prospective pilot study to investigate the effects of testosterone supplementation on central and peripheral insulin sensitivity in older men with upper body obesity and insulin resistance. Subjects/Methods Twenty men (62–78 years-old) with morning testosterone levels <13.9 nmol/L (400 ng/dL), waist circumference ≥ 102 cm, and HOMA-IR ≥ 4.0 or HgbA1C 5.7–6.4% applied transdermal testosterone (10 mg) daily for 20 weeks. Insulin sensitivity (Si) was determined by a 2-stage glucose clamp, liver and intramyocellular lipid by 1H-MR spectroscopy and body composition by DEXA. Results Testosterone supplementation significantly reduced total fat (−.9 ± 2.4 kg, p=0.002), trunk fat (−1.3 ± 1.4 kg, p=0.0007) and extremity fat (−0.7 ± 1.1 kg, p=0.01), and increased extremity lean tissue (+1.3 ± 1.4 kg, p=0.0006). Whole body (WB) Si improved by 21% (0.76 ± 1.57 dL/min per µU/mL, p=0.04) and insulin-stimulated glucose uptake (Rd) by 24% (0.91 ± 1.74 dL/min per µU/mL, p=0.03). Improvements in glucose kinetics were limited to men with reductions in trunk and extremity fat greater than median declines for the entire group. Reductions in intramyocellular lipid were associated with improvements in WB Si (p=0.04) and Rd (p=0.03). Change in Rd accounted for 90% of the change in WB Si. Hepatic glucose output and liver lipid/H2O were unchanged (p>0.05). Multivariable analyses revealed that reductions in extremity fat, trunk fat, and FFA levels during the clamp accounted for 45% (p=0.004), 31% (p=0.002) and 8% (p=0.04) of respective changes in Rd. Triglycerides decreased by −0.40 ± 0.67mmol/L (p=0.02), LDL-C by-0.35 ± 0.57 mmol/L (p=0.02), and HDL-C by −0.14 ± 0.19 mmol/L (p=0.004). Conclusions Testosterone supplementation that resulted in greater reductions in regional adiposity was associated with improved insulin sensitivity, lower LDL-C and fasting triglycerides, but lower HDL-C. Placebo controlled trials need to further examine the potential cardiometabolic risks/benefits of androgen supplementation for older men with low testosterone levels, central obesity, and insulin resistance.
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Affiliation(s)
- Fr Sattler
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - J He
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | - J Chukwuneke
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - H Kim
- Department of Radiology, University of Southern California, Los Angeles, CA, USA
| | - Y Stewart
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - P Colletti
- Department of Radiology, University of Southern California, Los Angeles, CA, USA
| | - Ke Yarasheski
- Department of Medicine, Washington University, St. Louis, MO, USA
| | - Ta Buchanan
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
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Trost LW, Hellstrom WJ. Testosterone Deficiency, Supplementation, and Prostate Cancer: Maintaining a Balanced Perspective. J Sex Med 2013; 10:2879-81. [DOI: 10.1111/jsm.12370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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108
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Actions of 17β-estradiol and testosterone in the mitochondria and their implications in aging. Ageing Res Rev 2013; 12:907-17. [PMID: 24041489 DOI: 10.1016/j.arr.2013.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/06/2013] [Indexed: 02/02/2023]
Abstract
A decline in the mitochondrial functions and aging are two closely related processes. The presence of estrogen and androgen receptors and hormone-responsive elements in the mitochondria represents the starting point for the investigation of the effects of 17β-estradiol and testosterone on the mitochondrial functions and their relationships with aging. Both steroids trigger a complex molecular mechanism that involves crosstalk between the mitochondria, nucleus, and plasma membrane, and the cytoskeleton plays a key role in these interactions. The result of this signaling is mitochondrial protection. Therefore, the molecular components of the pathways activated by the sexual steroids could represent targets for anti-aging therapies. In this review, we discuss previous studies that describe the estrogen- and testosterone-dependent actions on the mitochondrial processes implicated in aging.
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109
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Basaria S. Need for standardising adverse event reporting in testosterone trials. ACTA ACUST UNITED AC 2013; 19:32-3. [DOI: 10.1136/eb-2013-101402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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110
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Spitzer M, Huang G, Basaria S, Travison TG, Bhasin S. Reply. The importance of testosterone clinical trials. Nat Rev Endocrinol 2013; 9:438. [PMID: 23752777 DOI: 10.1038/nrendo.2013.73-c2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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