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Libby AE, Solt CM, Jackman MR, Sherk VD, Foright RM, Johnson GC, Nguyen TT, Breit MJ, Hulett N, Rudolph MC, Roberson PA, Wellberg EA, Jambal P, Scalzo RL, Higgins J, Kumar TR, Wierman ME, Pan Z, Shankar K, Klemm DJ, Moreau KL, Kohrt WM, MacLean PS. Effects of follicle-stimulating hormone on energy balance and tissue metabolic health after loss of ovarian function. Am J Physiol Endocrinol Metab 2024; 326:E626-E639. [PMID: 38536037 DOI: 10.1152/ajpendo.00400.2023] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/29/2024] [Accepted: 03/20/2024] [Indexed: 05/01/2024]
Abstract
Loss of ovarian function imparts increased susceptibility to obesity and metabolic disease. These effects are largely attributed to decreased estradiol (E2), but the role of increased follicle-stimulating hormone (FSH) in modulating energy balance has not been fully investigated. Previous work that blocked FSH binding to its receptor in mice suggested this hormone may play a part in modulating body weight and energy expenditure after ovariectomy (OVX). We used an alternate approach to isolate the individual and combined contributions of FSH and E2 in mediating energy imbalance and changes in tissue-level metabolic health. Female Wistar rats were ovariectomized and given the gonadotropin releasing hormone (GnRH) antagonist degarelix to suppress FSH production. E2 and FSH were then added back individually and in combination for a period of 3 wk. Energy balance, body mass composition, and transcriptomic profiles of individual tissues were obtained. In contrast to previous studies, suppression and replacement of FSH in our paradigm had no effect on body weight, body composition, food intake, or energy expenditure. We did, however, observe organ-specific effects of FSH that produced unique transcriptomic signatures of FSH in retroperitoneal white adipose tissue. These included reductions in biological processes related to lipogenesis and carbohydrate transport. In addition, rats administered FSH had reduced liver triglyceride concentration (P < 0.001), which correlated with FSH-induced changes at the transcriptomic level. Although not appearing to modulate energy balance after loss of ovarian function in rats, FSH may still impart tissue-specific effects in the liver and white adipose tissue that might affect the metabolic health of those organs.NEW & NOTEWORTHY We find no effect of follicle-stimulating hormone (FSH) on energy balance using a novel model in which rats are ovariectomized, subjected to gonadotropin-releasing hormone antagonism, and systematically given back FSH by osmotic pump. However, tissue-specific effects of FSH on adipose tissue and liver were observed in this study. These include unique transcriptomic signatures induced by the hormone and a stark reduction in hepatic triglyceride accumulation.
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Affiliation(s)
- Andrew E Libby
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Claudia M Solt
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
- Center for Scientific Review, National Institutes of Health, Bethesda, Maryland, United States
| | - Rebecca M Foright
- Department of Anatomy and Cell Biology, University of Kansas Medical Campus, Kansas City, Kansas, United States
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Thi-Tina Nguyen
- Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Matthew J Breit
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Nicholas Hulett
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Michael C Rudolph
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Campus, Oklahoma City, Oklahoma, United States
| | - Paul A Roberson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Elizabeth A Wellberg
- Stephenson Cancer Center, University of Oklahoma Health Sciences Campus, Oklahoma City, Oklahoma, United States
| | - Purevsuren Jambal
- Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Rebecca L Scalzo
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Janine Higgins
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - T Rajendra Kumar
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Margaret E Wierman
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Zhaoxing Pan
- Section of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Kartik Shankar
- Section of Nutrition, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Dwight J Klemm
- Cardiovascular Pulmonary Research Laboratory, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Kerrie L Moreau
- Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Wendy M Kohrt
- Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Paul S MacLean
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
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Bermudez B, Brown KC, Vahidi G, Ferreira Ruble AC, Heveran CM, Ackert-Bicknell CL, Sherk VD. Sex-specific effects of Fat-1 transgene on bone material properties, size, and shape in mice. JBMR Plus 2024; 8:ziad011. [PMID: 38523667 PMCID: PMC10958611 DOI: 10.1093/jbmrpl/ziad011] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 10/20/2024] [Accepted: 11/10/2024] [Indexed: 03/26/2024] Open
Abstract
Western diets are becoming increasingly common around the world. Western diets have high omega 6 (ω-6) and omega 3 (ω-3) fatty acids and are linked to bone loss in humans and animals. Dietary fats are not created equal; therefore, it is vital to understand the effects of specific dietary fats on bone. We aimed to determine how altering the endogenous ratios of ω-6:ω-3 fatty acids impacts bone accrual, strength, and fracture toughness. To accomplish this, we used the Fat-1 transgenic mice, which carry a gene responsible for encoding a ω-3 fatty acid desaturase that converts ω-6 to ω-3 fatty acids. Male and female Fat-1 positive mice (Fat-1) and Fat-1 negative littermates (WT) were given either a high-fat diet (HFD) or low-fat diet (LFD) at 4 wk of age for 16 wk. The Fat-1 transgene reduced fracture toughness in males. Additionally, male BMD, measured from DXA, decreased over the diet duration for HFD mice. In males, neither HFD feeding nor the presence of the Fat-1 transgene impacted cortical geometry, trabecular architecture, or whole-bone flexural properties, as detected by main group effects. In females, Fat-1-LFD mice experienced increases in BMD compared to WT-LFD mice; however, cortical area, distal femur trabecular thickness, and cortical stiffness were reduced in Fat-1 mice compared to pooled WT controls. However, reductions in stiffness were caused by a decrease in bone size and were not driven by changes in material properties. Together, these results demonstrate that the endogenous ω-6:ω-3 fatty acid ratio influences bone material properties in a sex-dependent manner. In addition, Fat-1 mediated fatty acid conversion was not able to mitigate the adverse effects of HFD on bone strength and accrual.
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Affiliation(s)
- Beatriz Bermudez
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204, United States
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States
| | - Kenna C Brown
- Department of Mechanical Engineering, Montana State University, Bozeman, MT 59717, United States
| | - Ghazal Vahidi
- Department of Mechanical Engineering, Montana State University, Bozeman, MT 59717, United States
| | - Ana C Ferreira Ruble
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States
| | - Chelsea M Heveran
- Department of Mechanical Engineering, Montana State University, Bozeman, MT 59717, United States
| | - Cheryl L Ackert-Bicknell
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States
| | - Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States
- Center for Scientific Review, National Institutes of Health, Bethesda, MD 20892, United States
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Abstract
PURPOSE OF REVIEW Obesity is highly prevalent and is associated with bone fragility and fracture. The changing nutrient availability to bone in obesity is an important facet of bone health. The goal of this article is to summarize current knowledge on the effects of carbohydrate and dietary fat availability on bone, particularly in the context of other tissues. RECENT FINDINGS The skeleton is a primary site for fatty acid and glucose uptake. The trafficking of carbohydrates and fats into tissues changes with weight loss and periods of weight gain. Exercise acutely influences nutrient uptake into bone and may affect nutrient partitioning to bone. Bone cells secrete hormones that signal to the brain and other tissues information about its energetic state, which may alter whole-body nutrient trafficking. There is a critical need for studies to address the changes that metabolic perturbations have on nutrient availability in bone.
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Affiliation(s)
- Beatriz Bermudez
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, USA
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Toru Ishii
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Yuan-Haw Wu
- Department of Surgery, Johns Hopkins University, Baltimore, MD, USA
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, USA
| | - Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Division of Translational and Clinical Sciences, Center for Scientific Review, National Institutes of Health, Bethesda, MD, USA.
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Tinsley JP, Carpenter RD, Pyle LL, Snell-Bergeon JK, Sherk VD, Shah VN. Femoral neck structural properties are altered in adults with type 1 diabetes. J Diabetes Complications 2022; 36:108308. [PMID: 36257238 PMCID: PMC10152407 DOI: 10.1016/j.jdiacomp.2022.108308] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/20/2022]
Abstract
AIMS To determine differences in hip geometry in adults with type 1 diabetes (T1D) compared with healthy adults without diabetes. METHODS In this cross-sectional study, 43 adults with T1D (mean age 56 years, 84 % female, 92 % White, mean duration of diabetes of 39 years, A1c of 7.8 %) and 40 adults without diabetes (mean age 60 years, 80 % female, 77 % white) who had hip dual-energy x-ray absorptiometry (DXA) scans from previous studies were included. Areal bone mineral density (aBMD) and measures of hip structural properties at the narrow neck, intertrochanteric and femoral shaft regions of the left proximal femur were analyzed between adults with T1D and controls using linear models controlled for age, sex, and body mass index. RESULTS There were no significant differences in DXA-based aBMD at the hip (0.769 ± 0.132 vs. 0.900 ± 0.139 g/cm2, p = 0.07) or femoral neck (0.722 ± 0.116 vs. 0.849 ± 0.114 g/cm2, p = 0.09) regions between adults with T1D and controls. When controlling for age, sex, and BMI, DXA-based aBMD at the hip (0.880 ± 0.022 vs. 0.943 ± 0.020 g/cm2, p = 0.02) and femoral neck (0.750 ± 0.021 vs. 0.812 ± 0.020 g/cm2, p = 0.02) regions were significantly lower in adults with T1D than controls. Cortical thickness was significantly lower in all three hip regions in adults with T1D than in controls (narrow-neck: 0.169 ± 0.005 vs. 0.186 ± 0.005 cm, p = 0.011; intertrochanteric: 0.388 ± 0.013 vs. 0.425 ± 0.012 cm, p = 0.017; femoral shaft: 0.529 ± 0.017 vs. 0.586 ± 0.016 cm, p = 0.006). Moreover, adults with T1D had a smaller cross-sectional area at the narrow-neck (3.06 ± 0.09 vs. 3.32 ± 0.08 cm2, p = 0.015), a higher femoral shaft endocortical diameter (2.23 ± 0.07 vs. 2.02 ± 0.06 cm, p = 0.011), and higher buckling ratios (an indicator of cortical instability) at the intertrochanteric (9.22 ± 0.34 vs. 8.23 ± 0.32, p = 0.016) and femoral shaft (3.32 ± 0.15 vs. 2.89 ± 0.14, p = 0.016) regions. CONCLUSIONS Adults with T1D have several significant differences in proximal femur morphology compared with controls. These morphological differences may adversely affect the mechanical integrity of the proximal femur, thereby contributing to an increased risk of fracture in the event of a fall.
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Affiliation(s)
- Jake P Tinsley
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, United States of America.
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, United States of America
| | - Laura L Pyle
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America; Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO, United States of America
| | - Janet K Snell-Bergeon
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America; Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Vanessa D Sherk
- Department of Orthopedics, University of Colorado School of Medicine, Aurora, CO, United States of America; Division of Translational and Clinical Sciences, Center for Scientific Review, National Institutes of Health, Bethesda, MD, United States of America
| | - Viral N Shah
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
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Chen Z, Sherk VD, Sharma-Ghimire P, Bemben MG, Bemben DA. Site-Specific Bone Differences and Energy Status in Male Competitive Runners and Road Cyclists. J Clin Densitom 2022; 25:150-159. [PMID: 34952789 DOI: 10.1016/j.jocd.2021.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/27/2021] [Accepted: 11/08/2021] [Indexed: 11/18/2022]
Abstract
The interaction between mechanical loading and energy availability on bone health in male endurance athletes merits further investigation. The purpose of this study was to compare bone status in male competitive runners and road cyclists and to investigate the influence of energy availability (EA) on bone mineral density (BMD). 18 competitive runners and 19 road cyclists (20-50 years) participated in this study. Areal BMD and body composition were assessed by dual energy x-ray absorptiometry. Volumetric bone variables at the 4% and 66% tibia sites were assessed by peripheral quantitative computed tomography. Energy availability (EA, 7-day dietary and exercise logs) and resting metabolic rate (RMR, open circuit spirometry) were measured as indicators of energy status. Bone loading history, calcium intake, and training history were assessed by questionnaires. After adjusting for age, runners had significantly greater (p < 0.05) areal BMD (femoral neck, left total hip), Z-scores (total body, hips sites), total bone mineral content and trabecular variables (bone mineral content, volumetric BMD, bone strength index) at tibia 4% site, and total volumetric BMD at tibia 66% site than the cyclists (p ≤ 0.05). At the tibia 66% site, cyclists had significantly greater (p < 0.05) total area, periosteal circumference, endosteal circumference, and strength-strain index than runners. Energy variables were similar for runners and cyclists; however, RMR and RMR ratio (measured RMR/predicted RMR) were significantly lower in cyclists (p < 0.001). In conclusion, there were site-specific differences in hip and tibia bone characteristics between runners and cyclists. RMR was associated with several bone outcomes; however, EA was not related to bone health in runners or to dual energy x-ray absorptiometry bone variables in cyclists.
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Affiliation(s)
- Zhaojing Chen
- Department of Kinesiology, California State University, San Bernardino, CA, USA.
| | - Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Pragya Sharma-Ghimire
- Department of Physical Education and Exercise Science, Lander University, Greenwood, SC, USA
| | - Michael G Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
| | - Debra A Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
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Bemben DA, Sherk VD, Buchanan SR, Kim S, Sherk K, Bemben MG. Acute and Chronic Bone Marker and Endocrine Responses to Resistance Exercise With and Without Blood Flow Restriction in Young Men. Front Physiol 2022; 13:837631. [PMID: 35370772 PMCID: PMC8969015 DOI: 10.3389/fphys.2022.837631] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/22/2022] [Indexed: 12/28/2022] Open
Abstract
In this study, we compared acute and chronic bone marker and hormone responses to 6 weeks of low intensity (20% 1RM) blood flow restriction (BFR20) resistance training to high intensity (70% 1RM) traditional resistance training (TR70) and moderate intensity (45% 1RM) traditional resistance training (TR45) in young men (18–35 years). Participants were randomized to one of the training groups or to a control group (CON). The following training programs were performed 3 days per week for 6 weeks for knee extension and knee flexion exercises: BFR20, 20%1RM, 4 sets (30, 15, 15, 15 reps) wearing blood flow restriction cuffs around the proximal thighs; TR70, 70% 1RM 3 sets 10 reps; and TR45, 45% 1RM 3 sets 15 reps. Muscle strength and thigh cross-sectional area were assessed at baseline, between week 3 and 6 of training. Acute bone marker (Bone ALP, CTX-I) and hormone (testosterone, IGF-1, IGFBP-3, cortisol) responses were assessed at weeks 1 and 6, with blood collection done in the morning after an overnight fast. The main findings were that the acute bone formation marker (Bone ALP) showed significant changes for TR70 and BFR20 but there was no difference between weeks 1 and 6. TR70 had acute increases in testosterone, IGF-1, and IGFBP-3 (weeks 1 and 6). BFR20 had significant acute increases in testosterone (weeks 1 and 6) and in IGF-1 at week 6, while TR45 had significant acute increases in testosterone (week 1), IGF-1 (week 6), and IGFBP-3 (week 6). Strength and muscle size gains were similar for the training groups. In conclusion, low intensity BFR resistance training was effective for stimulating acute bone formation marker and hormone responses, although TR70 showed the more consistent hormone responses than the other training groups.
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Affiliation(s)
- Debra A. Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, United States
- *Correspondence: Debra A. Bemben,
| | - Vanessa D. Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Samuel R. Buchanan
- Department of Health and Human Performance, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - SoJung Kim
- Department of Health and Exercise Science, Rowan University, Glassboro, NJ, United States
| | - Kyle Sherk
- Hanger Clinic, Denver, CO, United States
| | - Michael G. Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, United States
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Presby DM, Rudolph MC, Sherk VD, Jackman MR, Foright RM, Jones KL, Houck JA, Johnson GC, Higgins JA, Neufer PD, Eckel RH, MacLean PS. Lipoprotein Lipase Overexpression in Skeletal Muscle Attenuates Weight Regain by Potentiating Energy Expenditure. Diabetes 2021; 70:867-877. [PMID: 33536195 PMCID: PMC7980196 DOI: 10.2337/db20-0763] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 01/27/2021] [Indexed: 11/13/2022]
Abstract
Moderate weight loss improves numerous risk factors for cardiometabolic disease; however, long-term weight loss maintenance (WLM) is often thwarted by metabolic adaptations that suppress energy expenditure and facilitate weight regain. Skeletal muscle has a prominent role in energy homeostasis; therefore, we investigated the effect of WLM and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity-prone rats, WLM reduced fat oxidative capacity and downregulated genes involved in fat metabolism. Interestingly, even after weight was regained, genes involved in fat metabolism were also reduced. We then subjected mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, to WLM and weight regain and found that mCK-hLPL attenuates weight regain by potentiating energy expenditure. Irrespective of genotype, weight regain suppressed dietary fat oxidation and downregulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain. In summary, these results suggest that skeletal muscle fat oxidation is reduced during WLM and regain, and therapies that improve skeletal muscle fat metabolism may attenuate rapid weight regain.
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Affiliation(s)
- David M Presby
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Michael C Rudolph
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Vanessa D Sherk
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Matthew R Jackman
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Rebecca M Foright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS
| | - Kenneth L Jones
- Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO
| | - Julie A Houck
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Janine A Higgins
- Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute and the Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC
| | - Robert H Eckel
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Paul S MacLean
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Sherk VD, Heveran CM, Foright RM, Johnson GC, Presby DM, Ferguson VL, MacLean PS. Sex differences in the effect of diet, obesity, and exercise on bone quality and fracture toughness. Bone 2021; 145:115840. [PMID: 33418101 DOI: 10.1016/j.bone.2021.115840] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 06/05/2020] [Revised: 12/03/2020] [Accepted: 12/30/2020] [Indexed: 11/23/2022]
Abstract
Bone fragility and obesity are both diseases that are multifactorial in etiology and pathology. The contributing role of high fat diet (HFD) versus energy overconsumption on bone health is controversial. Exercise is often prescribed for improving bone health, but it is unclear whether HFD or overconsumption influences skeletal adaptations to exercise. Female and male Wistar rats were fed HFD or low fat diet (LFD) for 10 weeks, starting at 8 weeks of age. Within HFD, rats were labeled Obesity-Resistant (OR) or Obesity-Prone (OP) based on weight and fat gain. Within each diet and phenotype group, rats were randomized to treadmill exercise or sedentary control (SED) for the final 4 weeks. Femurs were assessed for fracture toughness. Cortical lamellar and nonlamellar bone microscale material behavior and chemistry were assessed using nanoindentation and Raman spectroscopy. Female bones had higher fracture toughness and mineral: matrix ratio than male bones. Diet and energy overconsumption affected bone characteristics in a sex-dependent manner, where the divergence between OP and OR in response to HFD occurred more rapidly in males. Diet composition, in general, had a stronger effect on bone quality than overconsumption. HFD dramatically decreased bone size and lamellar mineral:matrix compared to LFD. Effects of short-term exercise training on microscale tissue properties were generally more robust with LFD. Exercise enhanced the contrast between lamellar and nonlamellar bone for nanoindentation modulus but decreased this contrast for plastic work. Our data demonstrate the complexities in the relationship between diet and obesity and highlight the importance of addressing both aspects when characterizing bone quality and fracture resistance.
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Affiliation(s)
- Vanessa D Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
| | - Chelsea M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, MT, United States of America
| | - Rebecca M Foright
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Ginger C Johnson
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - David M Presby
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Virginia L Ferguson
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America; Department of Mechanical Engineering, University of Colorado, Boulder, CO; (5)BioFrontiers Institute, University of Colorado, Boulder, CO, United States of America
| | - Paul S MacLean
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
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Vahidi G, Rux C, Sherk VD, Heveran CM. Lacunar-canalicular bone remodeling: Impacts on bone quality and tools for assessment. Bone 2021; 143:115663. [PMID: 32987198 PMCID: PMC7769905 DOI: 10.1016/j.bone.2020.115663] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 07/15/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 01/06/2023]
Abstract
Osteocytes can resorb as well as replace bone adjacent to the expansive lacunar-canalicular system (LCS). Suppressed LCS remodeling decreases bone fracture toughness, but it is unclear how altered LCS remodeling impacts bone quality. The first goal of this review is to assess how LCS remodeling impacts LCS morphology as well as the composition and mechanical properties of surrounding bone tissue. The second goal is to compare tools available for the assessment of bone quality at length-scales that are physiologically-relevant to LCS remodeling. We find that changes to LCS morphology occur in response to a variety of physiological conditions and diseases and can be classified in two general phenotypes. In the 'aging phenotype', seen in aging and in some disuse models, the LCS is truncated and osteocytes apoptosis is increased. In the 'osteocytic osteolysis' phenotype, which is adaptive in some physiological settings and possibly maladaptive in others, the LCS enlarges and osteocytes generally maintain viability. Bone composition and mechanical properties vary near the osteocyte and change with at least some conditions that alter LCS morphology. However, few studies have evaluated bone composition and mechanical properties close to the LCS and so the impacts of LCS remodeling phenotypes on bone tissue quality are still undetermined. We summarize the current understanding of how LCS remodeling impacts LCS morphology, tissue-scale bone composition and mechanical properties, and whole-bone material properties. Tools are compared for assessing tissue-scale bone properties, as well as the resolution, advantages, and limitations of these techniques.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - C Rux
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - V D Sherk
- Department of Orthopedics, University of Colorado Anschutz School of Medicine, United States of America
| | - C M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America.
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10
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Sherk VD, Vigers T, Pyle L, Snell-Bergeon JK, Nadeau KJ, Rickels MR, Miller KM, Greenbaum CJ, Shah VN. Acute Hyperinsulinemia Alters Bone Turnover in Women and Men With Type 1 Diabetes. JBMR Plus 2020; 4:e10389. [PMID: 32995692 PMCID: PMC7507374 DOI: 10.1002/jbm4.10389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 04/20/2020] [Revised: 06/25/2020] [Accepted: 06/30/2020] [Indexed: 12/24/2022] Open
Abstract
Type 1 diabetes (T1D) increases fracture risk across the lifespan. The low bone turnover associated with T1D is thought to be related to glycemic control, but it is unclear whether peripheral hyperinsulinemia due to dependence on exogenous insulin has an independent effect on suppressing bone turnover. The purpose of this study was to test the bone turnover marker (BTM) response to acute hyperinsulinemia. Fifty‐eight adults aged 18 to 65 years with T1D over 2 years were enrolled at seven T1D Exchange Clinic Network sites. Participants had T1D diagnosis between age 6 months to 45 years. Participants were stratified based on their residual endogenous insulin secretion measured as peak C‐peptide response to a mixed meal tolerance test. BTMs (CTX, P1NP, sclerostin [SCL], osteonectin [ON], alkaline phosphatase [ALP], osteocalcin [OCN], osteoprotegerin [OPG], osteopontin [OPN], and IGF‐1) were assessed before and at the end of a 2‐hour hyperinsulinemic‐euglycemic clamp (HEC). Baseline ON (r = −0.30, p = .022) and OCN (r = −0.41, p = .002) were negatively correlated with age at T1D diagnosis, but baseline BTMs were not associated with HbA1c. During the HEC, P1NP decreased significantly (−14.5 ± 44.3%; p = .020) from baseline. OCN, ON, and IGF‐1 all significantly increased (16.0 ± 13.1%, 29.7 ± 31.7%, 34.1 ± 71.2%, respectively; all p < .001) during the clamp. The increase in SCL was not significant (7.3 ± 32.9%, p = .098), but the decrease in CTX (−12.4 ± 48.9, p = .058) neared significance. ALP and OPG were not changed from baseline (p = .23 and p = .77, respectively). Baseline ON and SCL were higher in men, but OPG was higher in women (all p ≤ .029). SCL was the only BTM that changed differently in women than men. There were no differences in baseline BTMs or change in BTMs between C‐peptide groups. Exogenous hyperinsulinemia acutely alters bone turnover, suggesting a need to determine whether strategies to promote healthy remodeling may protect bone quality in T1D. © 2020 American Society for Bone and Mineral Research © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Vanessa D Sherk
- Department of OrthopedicsSchool of Medicine University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Timothy Vigers
- Department of Biostatistics and Informatics Colorado School of Public Health University of Colorado Anschutz Medical Campus Aurora CO USA.,Department of Pediatrics, Section of EndocrinologySchool of Medicine University of Colorado Anschutz Medical Campus Aurora CO USA.,Barbara Davis Center for Diabetes University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Laura Pyle
- Department of Biostatistics and Informatics Colorado School of Public Health University of Colorado Anschutz Medical Campus Aurora CO USA.,Department of Pediatrics, Section of EndocrinologySchool of Medicine University of Colorado Anschutz Medical Campus Aurora CO USA.,Barbara Davis Center for Diabetes University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Janet K Snell-Bergeon
- Barbara Davis Center for Diabetes University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Kristen J Nadeau
- Children's Hospital Colorado University of Colorado School of Medicine Aurora CO USA
| | - Michael R Rickels
- Institute for Diabetes, Obesity & Metabolism University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | | | | | - Viral N Shah
- Barbara Davis Center for Diabetes University of Colorado Anschutz Medical Campus Aurora CO USA
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11
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Abstract
PURPOSE OF REVIEW To provide an update on the acute effects of glucose, insulin, and incretins on markers of bone turnover in those with and without diabetes. RECENT FINDINGS Bone resorption is suppressed acutely in response to glucose and insulin challenges in both healthy subjects and patients with diabetes. The suppression is stronger with oral glucose compared with intravenous delivery. Stronger responses with oral glucose may be related to incretin effects on insulin secretion or from a direct effect on bone turnover. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) infusion acutely suppresses bone resorption without much effect on bone formation. The bone turnover response to a metabolic challenge may be attenuated in type 2 diabetes, but this is an understudied area. A knowledge gap exists regarding bone turnover responses to a metabolic challenge in type 1 diabetes. The gut-pancreas-bone link is potentially an endocrine axis. This linkage is disrupted in diabetes, but the mechanism and progression of this disruption are not understood.
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Affiliation(s)
- Vanessa D Sherk
- Department of Orthopedics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Irene Schauer
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
| | - Viral N Shah
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
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12
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Foright RM, Johnson GC, Kahn D, Charleston CA, Presby DM, Bouchet CA, Wellberg EA, Sherk VD, Jackman MR, Greenwood BN, MacLean PS. Compensatory eating behaviors in male and female rats in response to exercise training. Am J Physiol Regul Integr Comp Physiol 2020; 319:R171-R183. [PMID: 32551825 PMCID: PMC7473893 DOI: 10.1152/ajpregu.00259.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 04/29/2020] [Accepted: 06/09/2020] [Indexed: 12/22/2022]
Abstract
Exercise is often used as a strategy for weight loss maintenance. In preclinical models, we have shown that exercise may be beneficial because it counters the biological drive to regain weight. However, our studies have demonstrated sex differences in the response to exercise in this context. In the present study, we sought to better understand why females and males exhibit different compensatory food eating behaviors in response to regular exercise. Using a forced treadmill exercise paradigm, we measured weight gain, energy expenditure, food intake in real time, and the anorectic effects of leptin. The 4-wk exercise training resulted in reduced weight gain in males and sustained weight gain in females. In male rats, exercise decreased intake, whereas it increased food intake in females. Our results suggest that the anorectic effects of leptin were not responsible for these sex differences in appetite in response to exercise. If these results translate to the human condition, they may reveal important information for the use and application of regular exercise programs.
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Affiliation(s)
- Rebecca M Foright
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Ginger C Johnson
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Darcy Kahn
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Catherine A Charleston
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - David M Presby
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Courtney A Bouchet
- Department of Psychology, University of Colorado Denver, Denver, Colorado
| | - Elizabeth A Wellberg
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Vanessa D Sherk
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Matthew R Jackman
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | | | - Paul S MacLean
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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13
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14
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Bermudez B, Presby DM, Foright RM, Javed N, Jackman MR, Higgins JA, Johnson GC, Carpenter RD, MacLean PS, Sherk VD. Diietary Fat Retention In Cortical Bone In Rats Fed High Fat Diet. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000687476.64924.ad] [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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15
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Sherk VD, Jackman MR, Higgins JA, Giles ED, Foright RM, Presby DM, Carpenter RD, Johnson GC, Oljira R, Houck JA, Maclean PS. Impact of Exercise and Activity on Weight Regain and Musculoskeletal Health Post-Ovariectomy. Med Sci Sports Exerc 2020; 51:2465-2473. [PMID: 31274683 DOI: 10.1249/mss.0000000000002082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The purpose of this study was to determine whether obesity and/or exercise training alters weight regain and musculoskeletal health after ovariectomy (OVX). Female rats were fed high-fat diet (HFD) to reveal obesity-prone (OP) and obesity-resistant (OR) phenotypes. The OP and OR exercising (EX) and sedentary (SED) rats were calorically restricted to lose 15% of body weight using medium-fat diet. Rats were then maintained in energy balance for 8 wk before OVX. After OVX and a brief calorically limited phase, rats were allowed to eat ad libitum until body weight plateaued. Starting at weight loss, EX ran 1 h·d, 6 d·wk, 15 m·min. Energy intake, spontaneous physical activity (SPA), and total energy expenditure were evaluated at the end of weight maintenance pre-OVX, and at three time points post-OVX: before weight regain, during early regain, and after regain. Data are presented as mean ± SE. Exercise attenuated weight regain after OVX in OP only (OP-EX, 123 ± 10 g; OP-SED, 165 ± 12 g; OR-EX, 121 ± 6 g; OR-SED, 116 ± 6 g), which was primarily an attenuation of fat gain. The early post-OVX increase in energy intake explained much of the weight regain, and was similar across groups. Exercising improved bone strength, as did maintaining SPA. Group differences in muscle mitochondrial respiration were not significant. The large decrease in SPA due to OVX was persistent, but early weight regain was dependent on decreased SPA. In conclusion, leanness and exercise do not necessarily protect from OVX-induced weight gain. Exercise prevented weight gain in obese rats, but loss of SPA was the greatest contributor to post-OVX weight gain. Thus, understanding the mechanisms resulting in reduction in SPA after ovarian hormone loss is critical in the prevention of menopause-associated metabolic dysfunction.
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Affiliation(s)
- Vanessa D Sherk
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Janine A Higgins
- Section of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Erin D Giles
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO.,Department of Nutrition and Food Science, Texas A&M University, College Station, TX
| | - Rebecca M Foright
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - David M Presby
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Robera Oljira
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Julie A Houck
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Paul S Maclean
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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16
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Kohrt WM, Wolfe P, Sherk VD, Wherry SJ, Wellington T, Melanson EL, Swanson CM, Weaver CM, Boxer RS. Dermal Calcium Loss Is Not the Primary Determinant of Parathyroid Hormone Secretion during Exercise. Med Sci Sports Exerc 2020; 51:2117-2124. [PMID: 31009423 DOI: 10.1249/mss.0000000000002017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Exercise can cause a decrease in serum ionized calcium (iCa) concentration, which stimulates parathyroid hormone (PTH) secretion and activates bone resorption. We postulated that dermal Ca loss during cycling exercise is the major determinant of the serum iCa, PTH, and bone resorption (C-terminal telopeptide of type 1 collagen [CTX]) responses. METHODS To investigate this, women (n = 13) and men (n = 12) age 18 to 45 yr performed the same exercise bout under cool (18°C) and warm (26°C) conditions. Exercise was 60 min of cycling at ~75% of peak aerobic power. Sweat samples were obtained during exercise using a skin patch method, and blood samples were obtained before and during exercise and during 60 min of recovery. RESULTS Sweat volume and estimated sweat Ca loss were 50% higher for the warm condition than the cool condition. Despite this, there were no differences between thermal conditions in the changes (mean, 95% confidence interval [95% CI]) in iCa (cool, -0.07 mg·dL; 95% CI, -0.16 to 0.03); warm, -0.07 mg·dL; 95% CI, -0.20 to 0.05), PTH (cool, 34.4 pg·mL; 95% CI, 23.6-45.2; warm: 35.8 pg·mL; 95% CI, 22.4-49.1), or CTX (cool, 0.11 ng·mL; 95% CI, 0.08-0.13; warm, 0.15 ng·mL; 95% CI, 0.11-0.18). Adjusting for exercise-related shifts in plasma volume revealed a marked decline in vascular iCa content in the first 15 min of exercise (cool, -0.85 mg·dL; 95% CI, -1.01 to -0.68; warm, -0.85 mg·dL; 95% CI, -1.05 to -0.66), before substantial sweat Ca loss had occurred. CONCLUSIONS This indicates that dermal Ca loss was not the primary trigger for the increases in PTH and CTX during exercise. Further research is necessary to understand the causes and consequences of the disruption in Ca homeostasis during exercise and specifically the extravascular shift in iCa.
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Affiliation(s)
- Wendy M Kohrt
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Denver, Aurora, CO.,Eastern Colorado VA Geriatric Research, Education, and Clinical Center, Aurora, CO
| | - Pamela Wolfe
- Department of Preventive Medicine and Biometrics, University of Colorado Denver, Aurora, CO
| | - Vanessa D Sherk
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Sarah J Wherry
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Denver, Aurora, CO.,Eastern Colorado VA Geriatric Research, Education, and Clinical Center, Aurora, CO
| | - Toby Wellington
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Edward L Melanson
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Denver, Aurora, CO.,Eastern Colorado VA Geriatric Research, Education, and Clinical Center, Aurora, CO.,Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Christine M Swanson
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Connie M Weaver
- Department of Nutrition Science, Purdue University, West Lafayette, IN
| | - Rebecca S Boxer
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Denver, Aurora, CO.,Eastern Colorado VA Geriatric Research, Education, and Clinical Center, Aurora, CO
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17
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Presby DM, Jackman MR, Rudolph MC, Sherk VD, Foright RM, Houck JA, Johnson GC, Orlicky DJ, Melanson EL, Higgins JA, MacLean PS. Compensation for cold-induced thermogenesis during weight loss maintenance and regain. Am J Physiol Endocrinol Metab 2019; 316:E977-E986. [PMID: 30912962 PMCID: PMC6580173 DOI: 10.1152/ajpendo.00543.2018] [Citation(s) in RCA: 7] [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: 12/13/2018] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 11/22/2022]
Abstract
Prevalence of obesity is exacerbated by low rates of successful long-term weight loss maintenance (WLM). In part, relapse from WLM to obesity is due to a reduction in energy expenditure (EE) that persists throughout WLM and relapse. Thus, interventions that increase EE might facilitate WLM. In obese mice that were calorically restricted to reduce body weight by ~20%, we manipulated EE throughout WLM and early relapse using intermittent cold exposure (ICE; 4°C, 90 min/day, 5 days/wk, within the last 3 h of the light cycle). EE, energy intake, and spontaneous physical activity were measured during the obese, WLM, and relapse phases. During WLM and relapse, the ICE group expended more energy during the light cycle because of cold exposure but expended less energy in the dark cycle, which led to no overall difference in total daily EE. The compensation in EE appeared to be mediated by activity, whereby the ICE group was more active during the light cycle because of cold exposure but less active during the dark cycle, which led to no overall effect on total daily activity during WLM and relapse. In brown adipose tissue of relapsing mice, the ICE group had greater mRNA expression of Dio2 and protein expression of UCP1 but lower mRNA expression of Prdm16. In summary, these findings indicate that despite robust increases in EE during cold exposures, ICE is unable to alter total daily EE during WLM or early relapse, likely due to compensatory behaviors in activity.
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Affiliation(s)
- David M Presby
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Matthew R Jackman
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Michael C Rudolph
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Vanessa D Sherk
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Rebecca M Foright
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Julie A Houck
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Ginger C Johnson
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - David J Orlicky
- Department of Pathology, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Edward L Melanson
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
- Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Janine A Higgins
- Department of Pediatrics, Section of Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Paul S MacLean
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus , Aurora, Colorado
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18
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Abstract
Osteocytes are the most prevalent cell in the skeleton and are the master regulator of bone remodeling. Despite the understanding that osteocytes have a multiyear lifespan, and some factors induce apoptosis in osteocytes, much less is understood about the induction and consequences of osteocyte senescence. Filling these gaps in knowledge will provide novel approaches to slowing age-related bone loss and preventing fragility fractures. The purpose of this review is to examine the roles of senescence and apoptosis in osteocytes in age-related bone loss. Based on evidence that exercise can prevent senescence in skeletal muscle, we provide a novel hypothesis by which exercise can prolong skeletal health.
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Affiliation(s)
- Vanessa D Sherk
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
| | - Clifford J Rosen
- Tufts University School of Medicine, Maine Medical Center Research Institute Scarborough, ME, United States of America
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19
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Radakovich LB, Marolf AJ, Shannon JP, Pannone SC, Sherk VD, Santangelo KS. Development of a microcomputed tomography scoring system to characterize disease progression in the Hartley guinea pig model of spontaneous osteoarthritis. Connect Tissue Res 2018; 59:523-533. [PMID: 29226725 PMCID: PMC6207938 DOI: 10.1080/03008207.2017.1409218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 07/27/2017] [Revised: 10/18/2017] [Accepted: 11/09/2017] [Indexed: 02/06/2023]
Abstract
AIM There is potential discrepancy between human and laboratory animal studies of osteoarthritis (OA), as radiographic assessment is the hallmark of the former and histopathology the standard for the latter. This suggests a need to evaluate OA in animal models in a manner similar to that utilized in people. Our study aimed to develop a whole joint grading scheme for microcomputed tomography (microCT) images in Hartley guinea pigs, a strain that recapitulates joint changes highlighted in human spontaneous OA. MATERIALS AND METHODS Knees from animals aged 2, 3, 5, 9, and 15 months were evaluated via whole joint microCT and standard histologic scoring. Quantitative microCT parameters, such as bone volume/total volume were also collected. RESULTS Both whole joint microCT and histologic scores increased with advancing age and showed strong correlation (r = 0.89. p < 0.0001). Histologic scores, which focus on cartilage changes, increased progressively with age. Whole joint microCT scores, which characterize bony changes, followed a stepwise pattern: scores increased between 3 and 5 months of age, stayed consistent between 5 and 9 months, and worsened again between 9 and 15 months. CONCLUSIONS This work provides data that advocates the use of a whole joint microCT scoring system in guinea pig studies of OA, as it provides important information regarding bony changes that occur at a different rate than articular cartilage changes. This grading scheme, in conjunction with histology and quantitative microCT measurements, may enhance the translational value of this animal model as it pertains to human work.
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Affiliation(s)
- Lauren B Radakovich
- a Department of Microbiology, Immunology, Pathology , Colorado State University , Fort Collins, CO, USA
| | - Angela J Marolf
- b Department of Environmental and Radiological Health Sciences , Colorado State University , Fort Collins, CO, USA
| | - John P Shannon
- a Department of Microbiology, Immunology, Pathology , Colorado State University , Fort Collins, CO, USA
| | - Stephen C Pannone
- a Department of Microbiology, Immunology, Pathology , Colorado State University , Fort Collins, CO, USA
| | - Vanessa D Sherk
- c Center for Women's Health Research , UC Anschutz Medical Campus , Aurora, CO, USA
| | - Kelly S Santangelo
- a Department of Microbiology, Immunology, Pathology , Colorado State University , Fort Collins, CO, USA
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20
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Kohrt WM, Wherry SJ, Wolfe P, Sherk VD, Wellington T, Swanson CM, Weaver CM, Boxer RS. Maintenance of Serum Ionized Calcium During Exercise Attenuates Parathyroid Hormone and Bone Resorption Responses. J Bone Miner Res 2018; 33:1326-1334. [PMID: 29572961 PMCID: PMC6538281 DOI: 10.1002/jbmr.3428] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [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: 12/28/2017] [Revised: 03/08/2018] [Accepted: 03/15/2018] [Indexed: 01/12/2023]
Abstract
Exercise can cause a decrease in serum ionized calcium (iCa) and increases in parathyroid hormone (PTH) and bone resorption. We used a novel intravenous iCa clamp technique to determine whether preventing a decline in serum iCa during exercise prevents increases in PTH and carboxy-terminal collagen crosslinks (CTX). Eleven cycling-trained men (aged 18 to 45 years) underwent two identical 60-min cycling bouts with infusion of Ca gluconate or saline. Blood sampling for iCa, total calcium (tCa), PTH, CTX, and procollagen type 1 amino-terminal propeptide (P1NP) occurred before, during, and for 4 hours after exercise; results are presented as unadjusted and adjusted for plasma volume shifts (denoted with subscript ADJ). iCa decreased during exercise with saline infusion (p = 0.01 at 60 min) and this was prevented by Ca infusion (interaction, p < 0.007); there were abrupt decreases in Ca content (iCaADJ and tCaADJ ) in the first 15 min of exercise under both conditions. PTH and CTX were increased at the end of exercise (both p < 0.01) on the saline day, and markedly attenuated (-65% and -71%; both p < 0.001) by Ca. CTX remained elevated for 4 hours after exercise on the saline day (p < 0.001), despite the return of PTH to baseline by 1 hour after exercise. P1NP increased in response to exercise (p < 0.001), with no difference between conditions, but the increase in P1NPADJ was not significant. Results for PTHADJ and CTXADJ were similar to unadjusted results. These findings demonstrate that bone resorption is stimulated early in exercise to defend serum iCa. Vascular Ca content decreased early in exercise, but neither the reason why this occurred, nor the fate of Ca, are known. The results suggest that the exercise-induced increase in PTH had an acute catabolic effect on bone. Future research should determine whether the increase in PTH generates an anabolic response that occurs more than 4 hours after exercise. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Wendy M Kohrt
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Eastern Colorado Geriatric Research, Education, and Clinical Center, VA Eastern Colorado Healthcare System, Denver, CO, USA
| | - Sarah J Wherry
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Pamela Wolfe
- Department of Preventive Medicine and Biometrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Vanessa D Sherk
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Toby Wellington
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Christine M Swanson
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Connie M Weaver
- Department of Nutrition Science, College of Health and Human Sciences, Purdue University, West Lafayette, IN, USA
| | - Rebecca S Boxer
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Eastern Colorado Geriatric Research, Education, and Clinical Center, VA Eastern Colorado Healthcare System, Denver, CO, USA
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21
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Foright RM, Presby DM, Sherk VD, Kahn D, Checkley LA, Giles ED, Bergouignan A, Higgins JA, Jackman MR, Hill JO, MacLean PS. Is regular exercise an effective strategy for weight loss maintenance? Physiol Behav 2018; 188:86-93. [PMID: 29382563 PMCID: PMC5929468 DOI: 10.1016/j.physbeh.2018.01.025] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/12/2018] [Accepted: 01/26/2018] [Indexed: 01/17/2023]
Abstract
Weight regain after weight loss is one of the most significant challenges to successful obesity treatment. Regular exercise has long been touted as a strategy for weight loss maintenance, but the lack of clear evidence in clinical trials has caused some to question its effectiveness. In this review, we present the arguments both questioning and in support of exercise as an obesity therapeutic. Our purpose is to bring clarity to the literature, present a unified perspective, and identify the gaps in knowledge that need to be addressed in future studies. Critical questions remain including sex differences, individual variability and compensatory behaviors in response to exercise, exercise adherence, the role of energy flux and the molecular mechanisms mediating the beneficial effects of exercise after weight loss and during weight regain. Future research should focus on these critical questions to provide a more complete understanding of the potential benefits of exercise on weight loss maintenance.
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Affiliation(s)
- R M Foright
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - D M Presby
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - V D Sherk
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - D Kahn
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - L A Checkley
- Coram/CVS Specialty Infusion Services, Denver, United States
| | - E D Giles
- Texas A&M University, Department of Nutrition & Food Science, Denver, United States
| | - A Bergouignan
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Anschutz Center for Health & Wellness, Denver, United States; Universite de Strasbourg, IPHC, Strasbourg, France; CNRS; UMR7178, Strasbourg, France
| | - J A Higgins
- Department of Pediatrics, Section of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - M R Jackman
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - J O Hill
- Anschutz Center for Health & Wellness, Denver, United States
| | - P S MacLean
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
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Monks J, Orlicky DJ, Stefanski AL, Libby AE, Bales ES, Rudolph MC, Johnson GC, Sherk VD, Jackman MR, Williamson K, Carlson NE, MacLean PS, McManaman JL. Maternal obesity during lactation may protect offspring from high fat diet-induced metabolic dysfunction. Nutr Diabetes 2018; 8:18. [PMID: 29695710 PMCID: PMC5916951 DOI: 10.1038/s41387-018-0027-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 12/17/2017] [Accepted: 02/07/2018] [Indexed: 01/21/2023] Open
Abstract
Background/Objectives The current obesity epidemic has spurred exploration of the developmental origin of adult heath and disease. A mother’s dietary choices and health can affect both the early wellbeing and lifelong disease-risk of the offspring. Subjects/Methods To determine if changes in the mother’s diet and adiposity have long-term effects on the baby’s metabolism, independently from a prenatal insult, we utilized a mouse model of diet-induced-obesity and cross-fostering. All pups were born to lean dams fed a low fat diet but were fostered onto lean or obese dams fed a high fat diet. This study design allowed us to discern the effects of a poor diet from those of mother’s adiposity and metabolism. The weaned offspring were placed on a high fat diet to test their metabolic function. Results In this feeding challenge, all male (but not female) offspring developed metabolic dysfunction. We saw increased weight gain in the pups nursed on an obesity-resistant dam fed a high fat diet, and increased pathogenesis including liver steatosis and adipose tissue inflammation, when compared to pups nursed on either obesity-prone dams on a high fat diet or lean dams on a low fat diet. Conclusion Exposure to maternal over-nutrition, through the milk, is sufficient to shape offspring health outcomes in a sex- and organ-specific manner, and milk from a mother who is obesity-prone may partially protect the offspring from the insult of a poor diet.
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Affiliation(s)
- Jenifer Monks
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - David J Orlicky
- Pathology Department, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Adrianne L Stefanski
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Andrew E Libby
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Elise S Bales
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Michael C Rudolph
- Division of Endocrinology, Metabolism, & Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism, & Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Vanessa D Sherk
- Division of Endocrinology, Metabolism, & Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism, & Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Kayla Williamson
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Nichole E Carlson
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul S MacLean
- Division of Endocrinology, Metabolism, & Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - James L McManaman
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
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Sherk VD, Jackman MR, Giles ED, Higgins JA, Foright RM, Presby DM, Johnson GC, Houck JA, Houser JL, Oljira R, MacLean PS. Prior weight loss exacerbates the biological drive to gain weight after the loss of ovarian function. Physiol Rep 2018; 5:e13272. [PMID: 28533263 PMCID: PMC5449558 DOI: 10.14814/phy2.13272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 02/01/2023] Open
Abstract
Both the history of obesity and weight loss may change how menopause affects metabolic health. The purpose was to determine whether obesity and/or weight loss status alters energy balance (EB) and subsequent weight gain after the loss of ovarian function. Female lean and obese Wistar rats were randomized to 15% weight loss (WL) or ad libitum fed controls (CON). After the weight loss period, WL rats were kept in EB at the reduced weight for 8 weeks prior to ovariectomy (OVX). After OVX, all rats were allowed to eat ad libitum until weight plateaued. Energy intake (EI), spontaneous physical activity, and total energy expenditure (TEE) were measured with indirect calorimetry before OVX, immediately after OVX, and after weight plateau. Changes in energy intake (EI), TEE, and weight gain immediately after OVX were similar between lean and obese rats. However, obese rats gained more total weight and fat mass than lean rats over the full regain period. Post-OVX, EI increased more (P ≤ 0.03) in WL rats (58.9 ± 3.5 kcal/d) than CON rats (8.5 ± 5.2 kcal/d), and EI partially normalized (change from preOVX: 20.5 ± 4.2 vs. 1.5 ± 4.9 kcal/day) by the end of the study. As a result, WL rats gained weight (week 1:44 ± 20 vs. 7 ± 25 g) more rapidly (mean = 44 ± 20 vs. 7 ± 25 g/week; P < 0.001) than CON Prior obesity did not affect changes in EB or weight regain following OVX, whereas a history of weight loss prior to OVX augmented disruptions in EB after OVX, resulting in more rapid weight regain.
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Affiliation(s)
- Vanessa D Sherk
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Erin D Giles
- Department of Nutrition & Food Science, Texas A&M University, College Station, Texas
| | - Janine A Higgins
- Section of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Rebecca M Foright
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - David M Presby
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Julie A Houck
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jordan L Houser
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Robera Oljira
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Paul S MacLean
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Sherk VD, Wherry SJ, Barry DW, Shea KL, Wolfe P, Kohrt WM. Calcium Supplementation Attenuates Disruptions in Calcium Homeostasis during Exercise. Med Sci Sports Exerc 2017; 49:1437-1442. [PMID: 28248693 DOI: 10.1249/mss.0000000000001239] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An exercise-induced decrease in serum ionized calcium (iCa) is thought to trigger an increase in parathyroid hormone (PTH), which can stimulate bone resorption. PURPOSE The purpose of this study was to determine whether taking a chewable calcium (Ca) supplement 30 min before exercise mitigates disruptions in Ca homeostasis and bone resorption in competitive male cyclists. METHODS Fifty-one men (18 to 45 yr old) were randomized to take either 1000 mg Ca (CA) or placebo (PL) 30 min before a simulated 35-km cycling time trial. Serum iCa and PTH were measured before and immediately after exercise and a marker of bone resorption (C-terminal telopeptide of type I collagen) was measured before and 30 min after exercise. RESULTS Serum iCa decreased in both groups from before to after exercise (mean ± SD, CA = 4.89 ± 0.16 to 4.76 ± 0.11 mg·dL, PL = 4.92 ± 0.15 to 4.66 ± 0.22 mg·dL, both P ≤ 0.01); the decrease was greater (P = 0.03) in the PL group. There was a nonsignificant (P = 0.07) attenuation of the increase in PTH by Ca supplementation (CA = 30.9 ± 13.0 to 79.7 ± 42.6 pg·mL, PL = 37.1 ± 14.8 to 111.5 ± 49.4 pg·mL, both P ≤ 0.01), but no effect of Ca on the change in C-terminal telopeptide of type I collagen, which increased in both groups (CA = 0.35 ± 0.17 to 0.50 ± 0.21 ng·mL, PL = 0.36 ± 0.13 to 0.54 ± 0.22 ng·mL, both P ≤ 0.01). CONCLUSION It is possible that ingesting Ca only 30 min before exercise was not a sufficient time interval to optimize gut Ca availability during exercise. Further studies will be needed to determine whether adequate Ca supplementation before and/or during exercise can fully mitigate the exercise-induced decrease in serum iCa and increases in PTH and bone resorption.
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Affiliation(s)
- Vanessa D Sherk
- 1Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; and 2Department of Preventative Medicine and Biostatistics, University of Colorado Anschutz Medical Campus, Aurora, CO
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Sherk VD, Carpenter RD, Giles ED, Higgins JA, Oljira RM, Johnson GC, Mills S, Maclean PS. Ibuprofen before Exercise Does Not Prevent Cortical Bone Adaptations to Training. Med Sci Sports Exerc 2017; 49:888-895. [PMID: 28079706 DOI: 10.1249/mss.0000000000001194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using a nonsteroidal anti-inflammatory drug (NSAID) before a single bout of mechanical loading can reduce bone formation response. It is unknown whether this translates to an attenuation of bone strength and structural adaptations to exercise training. PURPOSE This study aimed to determine whether nonsteroidal anti-inflammatory drug use before exercise prevents increases in bone structure and strength in response to weight-bearing exercise. METHODS Adult female Wistar rats (n = 43) were randomized to ibuprofen (IBU) or vehicle (VEH) and exercise (EX) or sedentary (SED) groups in a 2 × 2 (drug and activity) ANCOVA design with body weight as the covariate, and data are reported as mean ± SE. IBU drops (30 mg·kg BW) or VEH (volume equivalent) were administered orally 1 h before the bout of exercise. Treadmill running occurred 5 d·wk for 60 min·d at 20 m·min with a 5° incline for 12 wk. Micro-CT, mechanical testing, and finite element modeling were used to quantify bone characteristics. RESULTS Drug-activity interactions were not significant. Exercise increased tibia cortical cross-sectional area (EX = 5.67 ± 0.10, SED = 5.37 ± 0.10 mm, P < 0.01) and structural estimates of bone strength (Imax: EX = 5.16 ± 0.18, SED = 4.70 ± 0.18 mm, P < 0.01; SecModPolar: EX = 4.01 ± 0.11, SED = 3.74 ± 0.10 mm, P < 0.01). EX had increased failure load (EX = 243 ± 9, SED = 202 ± 7 N, P < 0.05) and decreased distortion in response to a 200-N load (von Mises stress at tibia-fibula junction: EX = 48.2 ± 1.3, SED = 51.7 ± 1.2 MPa, P = 0.01). There was no effect of ibuprofen on any measurement tested. Femur results revealed similar patterns. CONCLUSION Ibuprofen before exercise did not prevent the skeletal benefits of exercise in female rats. However, exercise that engenders higher bone strains may be required to detect an effect of ibuprofen.
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Affiliation(s)
- Vanessa D Sherk
- 1Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; 2Department of Mechanical Engineering, University of Colorado Denver, Denver, CO; and 3Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
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Abstract
UNLABELLED Bone health is critical for lower limb amputees, affecting their ability to use a prosthesis and their risk of osteoporosis. We found large losses in hip bone mineral density (BMD) and in amputated bone strength in the first year of prosthesis use, suggesting a need for load bearing interventions early post-amputation. INTRODUCTION Large deficits in hip areal BMD (aBMD) and residual limb volumetric BMD (vBMD) occur after lower limb amputation; however, the time course of these bone quality changes is unknown. The purpose of this study was to quantify changes in the amputated bone that occur during the early stages post-amputation. METHODS Eight traumatic unilateral amputees (23-53 years) were enrolled prior to surgery. Changes in total body, hip, and spine aBMD (dual-energy X-ray absorptiometry); in vBMD, stress-strain index (SSI), and muscle cross-sectional area (MCSA) (peripheral QCT); and in bone turnover markers were assessed after amputation prior to prosthesis fitting (pre-ambulatory) and at 6 and 12 months walking with prosthesis. RESULTS Hip aBMD of the amputated limb decreased 11-15%, which persisted through 12 months. The amputated bone had decreases (p < 0.01) in BMC (-26%), vBMD (-21%), and SSI (-25%) from pre-ambulatory to 6 months on a prosthesis, which was maintained between 6 and 12 months. There was a decrease (p < 0.05) in the proportion of bone >650 mg/cm3 (58 to 43% of total area) or >480 mg/cm3 (65% to 53%), suggesting an increase in cortical porosity after amputation. Bone alkaline phosphatase and sclerostin were elevated (p < 0.05) at pre-ambulatory and then decreased towards baseline. Bone resorption markers were highest at surgery and pre-ambulatory and then progressively decreased (p < 0.05). CONCLUSIONS Rapid and substantial losses in bone content and strength occur early after amputation and are not regained by 12 months of becoming ambulatory. Early post-amputation may be the most critical window for preventing bone loss.
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Affiliation(s)
- D A Bemben
- Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma, 1401 Asp Avenue, Norman, OK, 73019, USA.
| | - V D Sherk
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado at Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - W J J Ertl
- Department of Orthopedic Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - M G Bemben
- Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma, 1401 Asp Avenue, Norman, OK, 73019, USA
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Wherry SJ, Sherk VD, Wolfe P, Wellington T, Quick J, Boxer RS, Kohrt WM. Maintenance of Serum Ionized Calcium during Exercise Attenuates the Exercise-Related Increase in Bone Resorption. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000485926.81509.61] [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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Sherk VD, Dana Carpenter R, Giles ED, Oljira R, Mills S, Johnson GC, Higgins JA, MacLean PS. Ibuprofen Before Exercise Does Not Alter Cortical Bone Adaptations to Treadmill Running in Female Rats. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000486473.09360.cf] [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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Sherk KA, Sherk VD, Anderson MA, Bemben DA, Bemben MG. Lower limb neuromuscular function and blood flow characteristics in AFO-using survivors of stroke. J Geriatr Phys Ther 2016; 38:56-61. [PMID: 25032945 DOI: 10.1519/jpt.0000000000000017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND PURPOSE Ankle-foot orthoses (AFOs) and gait aids are commonly used by survivors of stroke to ambulate, but they have not been used as inclusion or exclusion criteria for physiological studies. The purpose of this study was to examine differences in neuromuscular function and blood flow characteristics between the lower limbs of ambulatory, AFO-using survivors of stroke (n = 9). METHODS The subjects were, on average, 14 years poststroke and had used an AFO for about 7 years. We used the following measures to assess both lower limbs: quadriceps muscular strength (manual muscle testing, 1RM), calf muscular endurance (single-leg heel raises), lower limb soft tissue composition and muscle cross-sectional area, calf resting blood flow (strain gauge plethysmography), and central neural drive of the plantar flexors (nerve stimulation). The sound limb was defined as the control. RESULTS Quadriceps strength, triceps surae endurance, and calf cross-sectional area all were greater in the sound limb than in the affected limb (relative differences: 76.3% ± 16.6%, 146.4% ± 24.6%, and 25.6% ± 5.7%, respectively). In addition, resting blood flow, peak torque, and central neural drive of the plantar flexors were significantly greater (relative differences: 38.7% ± 5.9%, 94.4% ± 17.9%, and 43.6% ± 12.0%, respectively) in the sound calf. DISCUSSION Our findings confirm that significant decrements in muscle performance, size, and blood flow persist in the affected limb many years after stroke despite a resumption of ambulation. CONCLUSIONS This cohort of ambulatory AFO users exhibited large variations in functional abilities. We recommend that future studies in stroke survivors consider AFO use in their research designs.
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Affiliation(s)
- Kyle A Sherk
- 1Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma. 2Hanger Orthotics and Prosthetics, Oklahoma City, Oklahoma. 3Health Science Center, University of Oklahoma, Oklahoma City, Oklahoma
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Shea KL, Barry DW, Sherk VD, Hansen KC, Wolfe P, Kohrt WM. Calcium supplementation and parathyroid hormone response to vigorous walking in postmenopausal women. Med Sci Sports Exerc 2015; 46:2007-13. [PMID: 24576866 DOI: 10.1249/mss.0000000000000320] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Disruptions in calcium (Ca) homeostasis during exercise may influence skeletal adaptations to exercise training. In young men, vigorous cycling causes increases in parathyroid hormone (PTH) and bone resorption (C-terminal telopeptides of type I collagen [CTX]); responses are attenuated by Ca supplementation. The study aimed to determine whether vigorous walking causes similar increases in PTH and CTX in older women and how the timing of Ca supplementation before and during exercise influences these responses. METHODS In experiment 1, 10 women (61 ± 4 yr) consumed 125 mL of either a Ca-fortified (1 g·L) or control beverage every 15 min during exercise starting 60 min before and continuing during 60 min of exercise. In experiment 2, 23 women (61 ± 4 yr) consumed 200 mL of a Ca-fortified (1 g·L) or control beverage every 15 min starting 15 min before and continuing during 60 min of exercise. The exercise was treadmill walking at 75%-80% V˙O2peak. RESULTS In experiment 1, serum ionized Ca decreased in the control condition (P < 0.001), but not with Ca supplementation. PTH increased after exercise on both days (Ca, P = 0.05; control, P = 0.009) but was attenuated by Ca supplementation (8.3 vs 26.1 pg·mL; P = 0.03). CTX increased only on the control day (P = 0.02). In experiment 2, serum ionized Ca decreased on Ca and control days (Ca and control, P < 0.001), but less so on the Ca day (P = 0.04). PTH (Ca and control, P < 0.001) and CTX (Ca, P = 0.02; control P = 0.007) increased on the Ca and control day, and there were no differences in the changes. CONCLUSION The timing of Ca supplementation may be a key mediator of Ca homeostasis during acute exercise. Further research is necessary to determine how this influences skeletal adaptations to training.
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Affiliation(s)
- Karen L Shea
- 1Division of Geriatric Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; 2Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; and 3Department of Preventative Medicine and Biostatistics, University of Colorado Anschutz Medical Campus, Aurora, CO
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Sherk VD, Foright R, Giles ED, Johnson GC, Lopez JL, Houck JA, Higgins JA, Jackman MR, MacLean PS. Initial Disruptions In Energy Balance After The Loss Of Ovarian Function Do Not Depend On Exercise Training Or Obesity Status In Rats. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000479060.97042.52] [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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Sharma-Ghimire P, Chen Z, Sherk VD, Bemben DA. Sclerostin Responses to Acute Whole-Body Vibration and Resistance Exercise in Young Women. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478399.11763.b4] [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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Abstract
Weight regain after weight loss is a substantial challenge in obesity therapeutics. Dieting leads to significant adaptations in the homeostatic system that controls body weight, which promotes overeating and the relapse to obesity. In this review, we focus specifically on the adaptations in white adipose tissues that contribute to the biological drive to regain weight after weight loss. Weight loss leads to a reduction in size of adipocytes and this decline in size alters their metabolic and inflammatory characteristics in a manner that facilitates the clearance and storage of ingested energy. We present the hypothesis whereby the long-term signals reflecting stored energy and short-term signals reflecting nutrient availability are derived from the cellularity characteristics of adipose tissues. These signals are received and integrated in the hypothalamus and hindbrain and an energy gap between appetite and metabolic requirements emerges and promotes a positive energy imbalance and weight regain. In this paradigm, the cellularity and metabolic characteristics of adipose tissues after energy-restricted weight loss could explain the persistence of a biological drive to regain weight during both weight maintenance and the dynamic period of weight regain.
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Affiliation(s)
- P S MacLean
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, Anschutz Health and Wellness Center, University of Colorado School of Medicine, Aurora, Colorado USA
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Pate KM, Sherk VD, Carpenter RD, Weaver M, Crapo S, Gally F, Chatham LS, Goldstrohm DA, Crapo JD, Kohrt WM, Bowler RP, Oberley-Deegan RE, Regan EA. The beneficial effects of exercise on cartilage are lost in mice with reduced levels of ECSOD in tissues. J Appl Physiol (1985) 2015; 118:760-7. [PMID: 25593283 DOI: 10.1152/japplphysiol.00112.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 11/22/2022] Open
Abstract
Osteoarthritis (OA) is associated with increased mechanical damage to joint cartilage. We have previously found that extracellular superoxide dismutase (ECSOD) is decreased in OA joint fluid and cartilage, suggesting oxidant damage may play a role in OA. We explored the effect of forced running as a surrogate for mechanical damage in a transgenic mouse with reduced ECSOD tissue binding. Transgenic mice heterozygous (Het) for the human ECSOD R213G polymorphism and 129-SvEv (wild-type, WT) mice were exposed to forced running on a treadmill for 45 min/day, 5 days/wk, over 8 wk. At the end of the running protocol, knee joint tissue was obtained for histology, immunohistochemistry, and protein analysis. Sedentary Het and WT mice were maintained for comparison. Whole tibias were studied for bone morphometry, finite element analysis, and mechanical testing. Forced running improved joint histology in WT mice. However, when ECSOD levels were reduced, this beneficial effect with running was lost. Het ECSOD runner mice had significantly worse histology scores compared with WT runner mice. Runner mice for both strains had increased bone strength in response to the running protocol, while Het mice showed evidence of a less robust bone structure in both runners and untrained mice. Reduced levels of ECSOD in cartilage produced joint damage when joints were stressed by forced running. The bone tissues responded to increased loading with hypertrophy, regardless of mouse strain. We conclude that ECSOD plays an important role in protecting cartilage from damage caused by mechanical loading.
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Affiliation(s)
- Kathryn M Pate
- Department of Medicine, National Jewish Health, Denver, Colorado;
| | - Vanessa D Sherk
- Department of Medicine, Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado, Denver, Colorado; and
| | - Michael Weaver
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Silvia Crapo
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Fabienne Gally
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Lillian S Chatham
- Department of Mechanical Engineering, University of Colorado, Denver, Colorado; and
| | | | - James D Crapo
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Wendy M Kohrt
- Department of Medicine, Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Russell P Bowler
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Rebecca E Oberley-Deegan
- Department of Medicine, National Jewish Health, Denver, Colorado; Department of Biochemistry and Molecular Biology, University of Nebraska Health Sciences Center, Omaha, Nebraska
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Sherk VD, Thiebaud RS, Chen Z, Karabulut M, Kim SJ, Bemben DA. Associations between pQCT-based fat and muscle area and density and DXA-based total and leg soft tissue mass in healthy women and men. J Musculoskelet Neuronal Interact 2014; 14:411-417. [PMID: 25524966 PMCID: PMC4433754] [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: 06/04/2023]
Abstract
UNLABELLED Peripheral Quantitative Computed Tomography (pQCT) can be used for muscle and fat area and density assessments. These may independently influence muscle and fat mass measurements from Dual Energy X-ray Absorptiometry (DXA). OBJECTIVE To determine associations between pQCT-derived soft tissue density and area measures and DXA-derived soft tissue mass. METHODS Linear regression models were developed based on BMI and calf fat and muscle cross-sectional area (FCSA and MCSA) and density measured by pQCT in healthy women (n=76) and men (n=82) aged 20-59 years. Independent variables for these models were leg and total bone-free lean mass (BFLM) and fat mass (FM) measured by DXA. RESULTS Sex differences (p<0.01) were found in both muscle (Mean±SE: Women: 78.6±0.4; Men: 79.9±0.2 mg/cm(3)) and fat (Women: 0.8±0.4 Men: 9.1±0.6 mg/cm(3)) density. BMI, fat density, and age (R(2)=0.86, p<0.01) best accounted for the variability in total FM. FCSA, BMI, and fat density explained the variance in leg FM (R(2)=0.87, p<0.01). MCSA and muscle density explained the variance in total (R(2)=0.65, p<0.01) and leg BFLM (R(2)=0.70, p<0.01). CONCLUSION Calf muscle and fat area and density independently predict lean and fat tissue mass.
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Affiliation(s)
- V D Sherk
- University of Colorado Anschutz Medical Campus, Division of Geriatric Medicine
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Shea KL, Gozansky WS, Sherk VD, Swibas TA, Wolfe P, Scherzinger A, Stamm E, Kohrt WM. Loss of bone strength in response to exercise-induced weight loss in obese postmenopausal women: results from a pilot study. J Musculoskelet Neuronal Interact 2014; 14:229-238. [PMID: 24879027 PMCID: PMC4391812] [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
OBJECTIVE Exercise-induced weight loss (WL) can lead to decreased areal bone mineral density (aBMD). It is unknown whether this translates into decreased volumetric BMD (vBMD) or bone strength. The purpose of this pilot study was to determine whether exercise-induced WL results in decreased vBMD and bone strength in postmenopausal women. METHODS Fourteen subjects participated in a 4-month endurance exercise WL intervention. A weight stable (WS) control group (n=10) was followed for 4 months. Proximal femur aBMD was measured by DXA. Femoral neck vBMD and estimates of bone strength (cross-sectional moment of inertia (CSMI) and section modulus (SM)) were measured by quantitative CT. RESULTS Women were 54.6±2.4 years, BMI 32.1±5.9 kg/m(2) and 54.4±2.9 years, BMI 27.9±3.6 kg/m(2) in the WL and WS groups, respectively. The WL group lost 3.0±2.6 kg which was predominately fat mass. There was a significant decrease in SMmax. Changes in CSMImax and total hip aBMD were not significant. Total hip vBMD did not decrease significantly in response to WL. There were no significant changes in the WS group. CONCLUSIONS WL may lead to decreased bone strength before changes in BMD are detected. Further studies are needed to determine whether bone-targeted exercise can preserve bone strength during WL.
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Affiliation(s)
- K L Shea
- Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Sherk VD, Shea KL, Wellington T, Kohrt WM. Disruptions in Calcium Homeostasis During High Intensity Exercise Under Different Ambient Conditions. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000493169.45757.fd] [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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38
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Kim E, Gregg LD, Kim L, Sherk VD, Bemben MG, Bemben DA. Hormone responses to an acute bout of low intensity blood flow restricted resistance exercise in college-aged females. J Sports Sci Med 2014; 13:91-96. [PMID: 24570611 PMCID: PMC3918573] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 09/23/2013] [Indexed: 06/03/2023]
Abstract
The purpose of this study was to determine whether the acute hormone response to exercise differed between low intensity blood flow restricted resistance exercise and traditional high-intensity resistance exercise in college-aged women. A total of 13 healthy women (aged 18-25 yrs), who were taking oral contraceptives, volunteered for this randomized crossover study. Subjects performed a session of low intensity blood flow restricted resistance exercise (BFR) (20% of 1-RM, 1 set 30 reps, 2 sets 15 reps) and a session of traditional high intensity resistance exercise without blood flow restriction (HI) (3 sets of 10 repetitions at 80% of 1-RM) on separate days. Fasting serum cortisol and growth hormone (GH) and blood lactate responses were measured in the morning pre and post exercise sessions. GH (Change: HI: 6.34 ± 1.72; BFR: 4.22 ± 1.40 ng·mL(-1)) and cortisol (Change: HI: 4.46 ± 1.53; BFR: 8.10 ± 2.30 ug·dL(-1)) significantly (p < 0.05) increased immediately post exercise for both protocols compared to baseline and there were no significant differences between the protocols for these responses. In contrast, blood lactate levels (HI: 7.35 ± 0.45; BFR: 4.02 ± 0.33 mmol·L(-1)) and ratings of perceived exertion were significantly (p < 0.01) higher for the HI protocol. In conclusion, acute BFR restricted resistance exercise stimulated similar increases in anabolic and catabolic hormone responses in young women. Key PointsGrowth hormone and cortisol levels significantly increased after a single bout of low intensity blood flow restricted resistance exercise in young women.There were no significant differences in hormone responses between the low intensity blood flow restricted protocol and the traditional high intensity higher total workload protocol.Low intensity blood flow restricted resistance exercise provides a sufficient stimulus to elicit anabolic and catabolic hormone responses in young women.
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Affiliation(s)
| | | | | | - Vanessa D Sherk
- Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma ; USA
| | | | - Debra A Bemben
- Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma ; USA
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Karabulut M, Sherk VD, Bemben DA, Bemben MG. Inflammation marker, damage marker and anabolic hormone responses to resistance training with vascular restriction in older males. Clin Physiol Funct Imaging 2013; 33:393-9. [PMID: 23701309 DOI: 10.1111/cpf.12044] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [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: 01/23/2013] [Accepted: 03/27/2013] [Indexed: 01/09/2023]
Abstract
The goal of this study was to examine anabolic hormone, muscle damage marker and inflammation marker responses to two types of resistance training protocols in older men. Thirty-six healthy older males (mean age = 56.6 ± 0.6 years) completed 6 weeks of high-intensity resistance training (HI-RT), low-intensity resistance training with vascular restriction (LI-BFR) or no exercise control group (CON) three times per week. Three upper body exercises were performed by both exercise groups at the same intensity (at 80% 1-RM), but lower body exercises were performed by the HI-RT group at 80% 1-RM and by the LI-BFR group at 20% 1-RM with vascular restriction. Resting serum creatine kinase (CK), interleukin 6 (IL-6), insulin-like growth factor-I (IGF-I), IGF binding protein 3 (IGFBP-3) and testosterone (T) were measured before and after training. No significant group differences in resting CK, IL-6, IGF-I, IGFBP-3 and T were detected following training (P>0.05). In addition, there were no significant changes in muscle cross-sectional area (CSA), but a trend for significant decreases in the percent changes in thigh subcutaneous fat (P = 0.051). Although training-induced anabolic hormone response did not reach statistical significance, our findings on CK and IL-6 indicated that the LI-BFR training protocol was safe and well tolerated for older men to perform to improve muscular strength.
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Affiliation(s)
- Murat Karabulut
- Department of Health and Human Performance, University of Texas at Brownsville, Brownsville, TX 78520, USA.
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40
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Abstract
Variability in peripheral quantitative computed tomography (pQCT) measurement sites and outcome variables limit direct comparisons of results between studies. Furthermore, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age and sex differences in estimates of tibia strength. An additional purpose of this study was to determine which tibia site or sites are most sensitive for detecting age and sex differences in tibia strength. Self-identifying Caucasian men (n=55) and women (n=59) aged 20-59yr had their tibias measured with pQCT from 5% to 85% of limb length in 10% increments distal to proximal. Bone strength index, strength strain index (SSI), moments of inertia (Ip, Imax, and Imin), and strength-to-mass ratios (polar moment of inertia to total bone mineral content [BMC] ratio [Ip:Tot.BMC] and strength strain index to total BMC ratio [SSI:Tot.BMC]) were quantified. There were significant (p<0.01) site effects for all strength variables and strength-to-mass ratios. Site×sex interaction effects were significant (p<0.05) for all strength variables. Men had greater (p<0.01) values than women for all strength variables. Sex differences in Ip, Imax, Ip:Tot.BMC, SSI, and SSI:Tot.BMC ratios were the smallest at the 15% site and peaked at various sites, depending on variable. Site×age interactions existed for Imax, Ip:Tot.BMC, and SSI:Tot.BMC. There were significant age effects, Imax, Ip:Tot.BMC, and SSI:Tot.BMC, as values were the lowest in the 20-29 age group. Age and sex differences varied by measurement site and variable, and larger sex differences existed for moments of inertia than SSI. Strength-to-mass ratios may reflect efficiency of the whole bone architecture.
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Affiliation(s)
- Vanessa D Sherk
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA.
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Sherk VD, Chrisman C, Smith J, Young KC, Singh H, Bemben MG, Bemben DA. Acute bone marker responses to whole-body vibration and resistance exercise in young women. J Clin Densitom 2013; 16:104-9. [PMID: 22902255 PMCID: PMC4109608 DOI: 10.1016/j.jocd.2012.07.009] [Citation(s) in RCA: 15] [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: 04/23/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022]
Abstract
Whole-body vibration (WBV) augments the musculoskeletal effects of resistance exercise (RE). However, its acute effects on bone turnover markers (BTM) have not been determined. This study examined BTM responses to acute high-intensity RE and high-intensity RE with WBV (WBV+RE) in young women (n=10) taking oral contraceptives in a randomized, crossover repeated measures design. WBV+RE exposed subjects to 5 one-minute bouts of vibration (20 Hz, 3.38 peak-peak displacement, separated by 1 min of rest) before RE. Fasting blood samples were obtained before (Pre), immediately after WBV (PostVib), immediately after RE (IP), and 30-min after RE (P30). Bone alkaline phosphatase did not change at any time point. Tartrate-resistant acid phosphatase 5b significantly increased (p<0.05) from the Pre to PostVib, then decreased from IP to P30 for both conditions. C-terminal telopeptide of type I collagen (CTX) significantly decreased (p<0.05) from Pre to PostVib and from Pre to P30 only for WBV+RE. WBV+RE showed a greater decrease in CTX than RE (-12.6% ± 4.7% vs -1.13% ± 3.5%). In conclusion, WBV was associated with acute decreases in CTX levels not elicited with RE alone in young women.
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Affiliation(s)
- Vanessa D Sherk
- Bone Density Research Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
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Sherk VD, Bemben DA, Bemben MG, Anderson MA. Age and sex differences in tibia morphology in healthy adult Caucasians. Bone 2012; 50:1324-31. [PMID: 22449446 PMCID: PMC4082662 DOI: 10.1016/j.bone.2012.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [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: 10/24/2011] [Revised: 02/21/2012] [Accepted: 03/07/2012] [Indexed: 11/28/2022]
Abstract
UNLABELLED Variability in peripheral Quantitative Computed Tomography (pQCT) measurement sites limits direct comparisons of results between studies. Further, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age group and sex differences in tibia morphology. Additional purposes of this study were to determine which tibia site or sites are most sensitive for detecting age and sex differences. METHODS Self-identifying Caucasian men (n=55) and women (n=59) ages 20-59 years and separated by decades had their non-dominant tibias measured with pQCT (Stratec XCT 3000) at every 10% of the limb length from 5% to 85% (distal to proximal). Volumetric BMD and BMC of the total, cortical and trabecular bone were determined, as well as periosteal (PeriC) and endosteal (EndoC) circumferences, and cortical thickness (CTh). RESULTS There were significant (p<0.01) site effects for all BMC, vBMD, PeriC and EndoC measures. Large sex differences (men>women) in Tot.BMC (21-28%) were paralleled by differences in Cort.BMC (21-25%) (p<0.01). Site∗sex interaction effects were significant (p<0.05) for BMC (peak sex difference: 5%, 15%, 25%, 85% sites) and circumference (peak sex difference: 65% site) variables. CTh and total vBMD were lowest (p<0.05) in 50-59 year group, and EndoC was highest in the 50-59 year group. Site∗age interactions existed for Cort.vBMD, Tot.BMC (85% site), and EndoC (25%, 35%, 55%-85% sites). Correcting for bone free lean body mass (BFLBM) greatly reduced sex differences, eliminating sex∗site interaction effects, but sex main effects remained significant. Correcting for BFLBM did not eliminate age effects. CONCLUSION The magnitude of age and sex differences in tibia variables varied by measurement site demonstrating the need for standardization of measurement sites.
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Affiliation(s)
- Vanessa D Sherk
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA.
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43
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Seo DI, Kim E, Fahs CA, Rossow L, Young K, Ferguson SL, Thiebaud R, Sherk VD, Loenneke JP, Kim D, Lee MK, Choi KH, Bemben DA, Bemben MG, So WY. Reliability of the one-repetition maximum test based on muscle group and gender. J Sports Sci Med 2012; 11:221-225. [PMID: 24149193 PMCID: PMC3737872] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 01/27/2012] [Indexed: 06/02/2023]
Abstract
The purpose of the present study was to examine the influence of muscle group location and gender on the reliability of assessing the one-repetition maximum (1RM) test. Thirty healthy males (n = 15) and females (n = 15) who experienced at least 3 months of continuous resistance training during the last 2 years aged 18-35 years volunteered to participate in the study. The 1RM for the biceps curl, lat pull down, bench press, leg curl, hip flexion, triceps extension, shoulder press, low row, leg extension, hip extension, leg press and squat were measured twice by a trained professional using a standard published protocol. Biceps curl, lat pull down, bench press, leg curl, hip flexion, and squat 1RM's were measured on the first visit, then 48 hours later, subjects returned for their second visit. During their second visit, 1RM of triceps extension, shoulder press, low row, leg extension, hip extension, and leg press were measured. One week from the second visit, participants completed the 1 RM testing as previously done during the first and second visits. The third and fourth visits were separated by 48 hours as well. All four visits to the laboratory were at the same time of day. A high intraclass correlation coefficient (ICC > 0.91) was found for all exercises, independent of gender and muscle group size or location, however there was a significant interaction for muscle group location (upper body vs. lower body) in females (p < 0.027). In conclusion, a standardized 1RM testing protocol with a short warm-up and familiarization period is a reliable measurement to assess muscle strength changes regardless of muscle group location or gender. Key pointsThe one repetition maximum (1RM) test is considered the gold standard for assessing muscle strength in non-laboratory situations.This study was done to examine the influence of muscle group location and gender on the reliability of assessing the 1RM test.The standardized 1RM testing protocol with a short warm-up and familiarization period is a reliable measurement technique to assess muscle strength changes regardless of muscle group location or gender.
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Affiliation(s)
- Dong-Il Seo
- Department of Social Athletics, Dongguk University , Gyeong-Ju, Korea
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Rossow LM, Fahs CA, Loenneke JP, Thiebaud RS, Sherk VD, Abe T, Bemben MG. Cardiovascular and perceptual responses to blood-flow-restricted resistance exercise with differing restrictive cuffs. Clin Physiol Funct Imaging 2012; 32:331-7. [DOI: 10.1111/j.1475-097x.2012.01131.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 03/09/2012] [Indexed: 01/01/2023]
Affiliation(s)
- Lindy M. Rossow
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Christopher A. Fahs
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Jeremy P. Loenneke
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Robert S. Thiebaud
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Vanessa D. Sherk
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Takashi Abe
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
| | - Michael G. Bemben
- Department of Health and Exercise Science; University of Oklahoma; Norman; OK; USA
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Loenneke JP, Fahs CA, Rossow LM, Sherk VD, Thiebaud RS, Abe T, Bemben DA, Bemben MG. Effects of cuff width on arterial occlusion: implications for blood flow restricted exercise. Eur J Appl Physiol 2011; 112:2903-12. [PMID: 22143843 DOI: 10.1007/s00421-011-2266-8] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/23/2011] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to determine the difference in cuff pressure which occludes arterial blood flow for two different types of cuffs which are commonly used in blood flow restriction (BFR) research. Another purpose of the study was to determine what factors (i.e., leg size, blood pressure, and limb composition) should be accounted for when prescribing the restriction cuff pressure for this technique. One hundred and sixteen (53 males, 63 females) subjects visited the laboratory for one session of testing. Mid-thigh muscle (mCSA) and fat (fCSA) cross-sectional area of the right thigh were assessed using peripheral quantitative computed tomography. Following the mid-thigh scan, measurements of leg circumference, ankle brachial index, and brachial blood pressure were obtained. Finally, in a randomized order, arterial occlusion pressure was determined using both narrow and wide restriction cuffs applied to the most proximal portion of each leg. Significant differences were observed between cuff type and arterial occlusion (narrow: 235 (42) mmHg vs. wide: 144 (17) mmHg; p = 0.001, Cohen's D = 2.52). Thigh circumference or mCSA/fCSA with ankle blood pressure, and diastolic blood pressure, explained the most variance in the cuff pressure required to occlude arterial flow. Wide BFR cuffs restrict arterial blood flow at a lower pressure than narrow BFR cuffs, suggesting that future studies account for the width of the cuff used. In addition, we have outlined models which indicate that restrictive cuff pressures should be largely based on thigh circumference and not on pressures previously used in the literature.
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Affiliation(s)
- Jeremy P Loenneke
- Department of Health and Exercise Science, Neuromuscular Research Laboratory, The University of Oklahoma, 1401 Asp Avenue, Room 104, Norman, OK 73019-0615, USA.
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Sherk VD, Bemben MG, Palmer IJ, Bemben DA. Effects of filtering methods on muscle and fat cross-sectional area measurement by pQCT: a technical note. Physiol Meas 2011; 32:N65-72. [DOI: 10.1088/0967-3334/32/12/n01] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Moon JR, Stout JR, Walter AA, Smith AE, Stock MS, Herda TJ, Sherk VD, Young KC, Lockwood CM, Kendall KL, Fukuda DH, Graef JL, Cramer JT, Beck TW, Esposito EN. Mechanical scale and load cell underwater weighing: a comparison of simultaneous measurements and the reliability of methods. J Strength Cond Res 2011; 25:652-61. [PMID: 21273906 DOI: 10.1519/jsc.0b013e3181e99c2d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Both load cell and mechanical scale-based hydrostatic weighing (HW) systems are used for the measurement of underwater weight. However, there has been no direct comparison of the 2 methods. The purpose of the current investigation was to simultaneously compare a load cell and mechanical scale for use in HW. Twenty-seven men and women (mean ± SD, age: 22 ± 2 years) participated in the 2-day investigation. Each subject completed 2 HW assessments 24 hours apart. Single-day comparisons of all trials for both days revealed no significant difference between the mechanical scale and the load cell (mean difference < 0.016 kg, p > 0.05). True underwater weight values were not significantly different between methods for either days (mean difference < 0.014 kg, p > 0.05) and accounted for a mean difference in percent fat (%FAT) of <0.108%. The 95% limits of agreement indicated a maximum difference between methods of 0.53% FAT. Both methods produced similar reliability SEM values (mechanical SEM < 0.72%FAT, load cell SEM < 0.75%FAT). In conclusion, there was no difference between mechanical scale and load cell measurements of underwater weights and the added precision of the load cell only marginally (<0.16%FAT) improved day-to-day reliability. Either a mechanical scale or load cell can be used for HW with similar accuracy and reliability in young adults with a body mass index of 18.7-34.4 (5-25%FAT).
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Affiliation(s)
- Jordan R Moon
- Human Performance and Body Composition Laboratories, Department of Sports Fitness and Health, United States Sports Academy, Daphne, Alabama, USA.
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Rossow LM, Fahs CA, Sherk VD, Seo DI, Bemben DA, Bemben MG. The effect of acute blood-flow-restricted resistance exercise on postexercise blood pressure. Clin Physiol Funct Imaging 2011; 31:429-34. [DOI: 10.1111/j.1475-097x.2011.01038.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sherk VD, Malone SP, Bemben MG, Knehans AW, Palmer IJ, Bemben DA. Leptin, fat mass, and bone mineral density in healthy pre- and postmenopausal women. J Clin Densitom 2011; 14:321-5. [PMID: 21600824 DOI: 10.1016/j.jocd.2011.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [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: 10/15/2010] [Revised: 02/23/2011] [Accepted: 03/30/2011] [Indexed: 12/31/2022]
Abstract
The purpose was to examine relationships between age, fat mass, and bone mineral density (BMD) with resting leptin levels in premenopausal and postmenopausal women. Young (aged 18-30 yr, n=30) and estrogen-deficient postmenopausal (aged 55-75 yr, n=43) women were recruited. Total body and segmental fat mass and bone-free lean body mass (BFLBM) and total body, lumbar spine, and proximal femur BMD were assessed using dual-energy X-ray absorptiometry. Serum-resting, fasted leptin levels were measured by Immunoradiometric Assay (IRMA), and leptin-to-fat mass ratios were calculated. Young and older women had similar amounts of BFLBM, but older women had greater (p<0.05) amounts of fat mass and 35% higher leptin levels. Age differences in leptin concentrations were no longer significant after controlling for fat mass. Older women had significantly (p<0.05) lower hip BMD values. Age was negatively related (r=-0.29, p<0.05) to leptin:trunk fat ratio. Increases in fat mass, not menopause per se, contributes to higher leptin levels in older women. Relationships between leptin and BMD may be age dependent.
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Affiliation(s)
- Vanessa D Sherk
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
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Sherk KA, Kim DY, Singh H, Sherk VD, Bemben DA, Bemben MG. KAATSU Training Improves Strength and mCSA of the Thigh Equivalent to High Intensity Resistance Training. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402796.53462.db] [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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