1
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Gillen MM, Rosenbaum DL, Winter VR, Bloomer SA. Hormonal contraceptive use and women's well-being: links with body image, eating behavior, and sleep. PSYCHOL HEALTH MED 2024; 29:905-916. [PMID: 37220269 DOI: 10.1080/13548506.2023.2216468] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 05/16/2023] [Indexed: 05/25/2023]
Abstract
The goal of the current study was to examine associations between hormonal contraceptive use and indicators of well-being including body image, eating behavior, sleep and energy level. Drawing on a health protection framework, we expected that individuals who use hormonal contraceptives would be more attuned to health and report more positive health attitudes and behaviors on these dimensions. Undergraduate college women (N = 270; M = 19.39 years, SD = 2.43, range 18-39 years) from diverse racial/ethnic and sexual orientation groups completed a survey online. Measures included hormonal contraception use, body image, weight control behavior, breakfast consumption, sleep behavior, and daytime energy level. Nearly 1/3 (30.9%) of the sample reported current hormonal contraceptive use, with most users reporting use of birth control pills (74.7%). Women who used hormonal contraceptives reported significantly higher appearance orientation and body surveillance, lower average energy, more frequent night awakenings, and more naps. Longer duration of hormonal contraceptive use was significantly related to higher body surveillance, and engaging in more unhealthy weight control behavior. Hormonal contraceptive use is not related to indicators of greater well-being. Rather, hormonal contraceptive use is related to greater attention to appearance, lower daytime energy, and some indicators of poorer sleep quality. Clinicians who prescribe hormonal contraceptives should attend to body image, sleep and energy concerns among users.
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Affiliation(s)
- Meghan M Gillen
- Division of Social Sciences, The Pennsylvania State University, Abington, PA, USA
| | - Diane L Rosenbaum
- Division of Social Sciences, The Pennsylvania State University, Abington, PA, USA
| | | | - Steven A Bloomer
- Division of Science and Engineering, The Pennsylvania State University, Abington, PA, USA
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2
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Haak JL, Kregel KC, Bloomer SA. Altered accumulation of hepatic mitochondrial antioxidant proteins with age and environmental heat stress. J Appl Physiol (1985) 2023; 135:1339-1347. [PMID: 37881850 PMCID: PMC10979832 DOI: 10.1152/japplphysiol.00610.2023] [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] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
Aging impairs overall physiological function, particularly the response to environmental stressors. Repeated heat stress elevates reactive oxygen species and macromolecular damage in the livers of aged animals, likely due to mitochondrial dysfunction. The goal of this investigation was to determine potential mechanisms for mitochondrial dysfunction after heat stress by evaluating key redox-sensitive and antioxidant proteins (Sirt-3, MnSOD, Trx-2, and Ref-1). We hypothesized that heat stress would result in greater mitochondrial abundance of these proteins, but that aging would attenuate this response. For this purpose, young (6 mo) and old (24 mo) Fisher 344 rats were exposed to heat stress on two consecutive days. During each heating trial, colonic temperature was elevated to 41°C during the first 60 min, and then clamped at this temperature for 30 min. Nonheated animals served as controls. At 2 and 24 h after the second heat stress, hepatic mitochondria were isolated from each animal, and then immunoblotted for Sirt-3, acetylated lysine residues (Ac-K), MnSOD, Trx-2, and Ref-1. Aging increased Sirt-3 and lowered Ac-K. In response to heat stress, Sirt-3, Ac-K, MnSOD, and Ref-1 increased in mitochondrial fractions in both young and old animals. At 2 h after the second heat stress, mitochondrial Trx-2 declined in old, but not in young animals. Our results suggest that some components of the response to heat stress are preserved with aging. However, the decline in Trx-2 represents a potential mechanism for age-related mitochondrial damage and dysfunction after heat stress.NEW & NOTEWORTHY Our results suggest heat stress-induced mitochondrial translocation of Sirt-3, MnSOD, and Ref-1 in young and old animals. Aged rats experienced a decline in Trx-2 after heat stress, suggesting a potential mechanism for age-related mitochondrial dysfunction.
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Affiliation(s)
- Jodie L Haak
- Health Sciences Department, Drexel University, Philadelphia, Pennsylvania, United States
| | - Kevin C Kregel
- Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa, United States
| | - Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, Pennsylvania, United States
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3
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Rosenbaum DL, Gillen MM, Bloomer SA. The effects of sleep on body image: examining the roles of depression, perceived stress, and anxiety. J Am Coll Health 2023:1-9. [PMID: 36977339 DOI: 10.1080/07448481.2023.2186153] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/19/2022] [Accepted: 02/26/2023] [Indexed: 06/18/2023]
Abstract
Objective: Although health and wellness behaviors are associated with positive body image, research is limited regarding the relationship between sleep and positive body image. We propose that negative affective states may link sleep and body image. Specifically, we examined whether better sleep may relate to positive body image through reductions in negative affective experiences. Participants: Participants were 269 undergraduate women. Methods: Cross-sectional surveys were administered. Results: We found correlations in the expected directions between sleep, positive body image variables (i.e., body appreciation, appearance evaluation, and appearance orientation), and negative affective states (i.e., depression, anxiety, and stress). There were group differences in negative affective states and body image based on adequate sleep. Data supported indirect effects of sleep through depression on appearance evaluation, and through depression and stress on body appreciation, respectively. Conclusions: Our findings indicate sleep warrants further research attention as a wellness behavior related to more positive body image.
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Affiliation(s)
- Diane L Rosenbaum
- Psychological and Social Sciences, Abington College, Pennsylvania State University, Abington, PA, USA
| | - Meghan M Gillen
- Psychological and Social Sciences, Abington College, Pennsylvania State University, Abington, PA, USA
| | - Steven A Bloomer
- Biology, Abington College, Pennsylvania State University, Abington, PA, USA
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4
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Bloomer SA. Hepatic Macrophage Abundance and Phenotype in Aging and Liver Iron Accumulation. Int J Mol Sci 2022; 23:ijms23126502. [PMID: 35742946 PMCID: PMC9223835 DOI: 10.3390/ijms23126502] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 12/14/2022] Open
Abstract
Liver macrophages serve important roles in iron homeostasis through phagocytosis of effete erythrocytes and the export of iron into the circulation. Conversely, intracellular iron can alter macrophage phenotype. Aging increases hepatic macrophage number and nonparenchymal iron, yet it is unknown whether age-related iron accumulation alters macrophage number or phenotype. To evaluate macrophages in a physiological model of iron loading that mimicked biological aging, young (6 mo) Fischer 344 rats were given one injection of iron dextran (15 mg/kg), and macrophage number and phenotype were evaluated via immunohistochemistry. A separate group of old (24 mo) rats was treated with 200 mg/kg deferoxamine every 12 h for 4 days. Iron administration to young rats resulted in iron concentrations that matched the values and pattern of tissue iron deposition observed in aged animals; however, iron did not alter macrophage number or phenotype. Aging resulted in significantly greater numbers of M1 (CD68+) and M2 (CD163+) macrophages in the liver, but neither macrophage number nor phenotype were affected by deferoxamine. Double-staining experiments demonstrated that both M1 (iNOS+) and M2 (CD163+) macrophages contained hemosiderin, suggesting that macrophages of both phenotypes stored iron. These results also suggest that age-related conditions other than iron excess are responsible for the accumulation of hepatic macrophages with aging.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, 1600 Woodland Rd, Abington, PA 19001, USA
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5
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Bloomer SA, Brown KE. Hepcidin and Iron Metabolism in Experimental Liver Injury. Am J Pathol 2021; 191:1165-1179. [PMID: 33891874 DOI: 10.1016/j.ajpath.2021.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/25/2021] [Accepted: 04/06/2021] [Indexed: 11/18/2022]
Abstract
The liver plays a pivotal role in the regulation of iron metabolism through its ability to sense and respond to iron stores by release of the hormone hepcidin. Under physiologic conditions, regulation of hepcidin expression in response to iron status maintains iron homeostasis. In response to tissue injury, hepcidin expression can be modulated by other factors, such as inflammation and oxidative stress. The resulting dysregulation of hepcidin is proposed to account for alterations in iron homeostasis that are sometimes observed in patients with liver disease. This review describes the effects of experimental forms of liver injury on iron metabolism and hepcidin expression. In general, models of acute liver injury demonstrate increases in hepcidin mRNA and hypoferremia, consistent with hepcidin's role as an acute-phase reactant. Conversely, diverse models of chronic liver injury are associated with decreased hepcidin mRNA but with variable effects on iron status. Elucidating the reasons for the disparate impact of different chronic injuries on iron metabolism is an important research priority, as is a deeper understanding of the interplay among various stimuli, both positive and negative, on hepcidin regulation. Future studies should provide a clearer picture of how dysregulation of hepcidin expression and altered iron homeostasis impact the progression of liver diseases and whether they are a cause or consequence of these pathologies.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, Pennsylvania
| | - Kyle E Brown
- Iowa City Veterans Administration Medical Center, Iowa City, Iowa; Division of Gastroenterology-Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa; Program in Free Radical and Radiation Biology, Department of Radiation Oncology, University of Iowa Carver College of Medicine, Iowa City, Iowa.
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6
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Abstract
Aging is associated with chronic, low-grade inflammation that adversely affects physiological function. The liver regulates systemic inflammation; it is a source of cytokine production and also scavenges bacteria from the portal circulation to prevent infection of other organs. The cells with primary roles in these functions, hepatic macrophages, become more numerous in the liver with "normal" aging (i.e., in the absence of disease). Here, we demonstrate evidence and potential mechanisms for this phenomenon, which include augmented tumor necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) expression in the liver. Also, we discuss how an age-related impairment in autophagy within macrophages leads to a pro-oxidative state and ensuing production of proinflammatory cytokines, particularly interleukin 6 (IL-6). Given that the liver is a rich source of macrophages, we posit that it represents a major source of the elevated systemic IL-6 observed with aging, which is associated with physiological dysfunction. Testing a causal role for liver macrophage production of IL-6 during aging remains a challenge, yet interventions that have targeted macrophages and/or IL-6 have demonstrated promise in treating age-related diseases. These studies have demonstrated an age-related, deleterious reprogramming of macrophage function, which worsens pathology. Therefore, hepatic macrophage accrual is indeed a cause for concern, and therapies that attenuate the aged phenotype of macrophages will likely prove useful in promoting healthy aging.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, Pennsylvania
| | - Eric D Moyer
- Penn State College of Medicine, Hershey, Pennsylvania
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7
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Bloomer SA, Brown KE, Kregel KC. Renal Iron Accumulation and Oxidative Injury With Aging: Effects of Treatment With an Iron Chelator. J Gerontol A Biol Sci Med Sci 2021; 75:680-684. [PMID: 30794723 DOI: 10.1093/gerona/glz055] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Indexed: 11/13/2022] Open
Abstract
Dysregulation of iron metabolism in the kidney may contribute to age-related increases in renal oxidative stress and dysfunction. This study assessed the effects of short-term iron chelation on markers of iron status, oxidative stress, inflammation, and autophagy in the kidneys of old rats. Old Fischer 344 rats (24 months) were treated with deferoxamine (DFO; 200 mg/kg, twice daily for 4.5 days); saline-treated young (6 months) and old rats served as controls. Renal nonheme iron was significantly higher in the old rats, with iron localized in the renal cortex. Ferritin levels were elevated in the kidneys of old rats, while expression of several antioxidant enzymes and mitochondrial proteins were reduced and protein carbonyls increased compared to young rats. DFO treatment significantly reduced ferritin levels, and increased transferrin receptor-1 protein, but did not affect nonheme iron content or protein carbonyls, nor did it reverse age-related changes in antioxidant enzymes and mitochondrial proteins. Although short-term DFO treatment did not mitigate the age-related increase in iron content and oxidative damage, this work demonstrates that old rats respond appropriately to DFO, suggesting that optimization of iron chelation regimens could be useful in improving renal homeostasis with aging.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State University, Abington College, Pennsylvania
| | - Kyle E Brown
- Iowa City Veterans Administration Medical Center, Iowa.,Division of Gastroenterology-Hepatology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City.,Program in Free Radical and Radiation Biology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City
| | - Kevin C Kregel
- Department of Health and Human Physiology, The University of Iowa, Iowa City
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8
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Bloomer SA, Broadhurst KA, Maleah Mathahs M, Brown KE. Effects of long-term ethanol ingestion on hepatic iron metabolism in two mouse strains. Clin Exp Pharmacol Physiol 2020; 48:534-542. [PMID: 33319364 DOI: 10.1111/1440-1681.13445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 01/21/2023]
Abstract
The mechanisms responsible for dysregulation of iron metabolism in response to ethanol ingestion are poorly understood. Relatively brief ethanol exposures in rodents are associated with reduced hepatic hepcidin expression without increases in hepatic iron content. This study evaluated the effects of long-term ethanol treatment on hepatic iron metabolism in two mouse strains. Ethanol was administered in the drinking water to C57BL/6 and BALB/c mice for up to 11 months. Hepatic histology and iron concentrations (HIC) were assessed, along with expression of relevant genes and proteins by real-time RT-PCR and western blot, respectively. The livers of ethanol-consuming mice of both strains showed mild steatosis without inflammation or fibrosis. Stainable hepatocyte iron was modestly increased in both strains ingesting ethanol, although hepatic iron concentrations were significantly higher only in C57BL/6 mice. Long-term ethanol did not affect hepcidin mRNA (Hamp1 or Hamp2) in either strain, nor was the expression of several oxidative stress-responsive genes (glutamate cysteine ligase, gamma-glutamyl transpeptidase, heme oxygenase-1 and growth differentiation factor 15) altered in response to ethanol, suggesting that oxidative stress and suppression of hepcidin expression in short-term ethanol feeding models may be transient phenomena that resolve as mice adapt to ethanol exposure. This murine model of chronic ethanol ingestion demonstrates modest increases in hepatic iron without changes in hepcidin expression, markers of oxidative stress or significant histologic liver injury. Further investigations are needed to characterize the mechanisms of dysregulated iron metabolism resulting from chronic ethanol ingestion.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, PA, USA
| | - Kimberly A Broadhurst
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - M Maleah Mathahs
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Kyle E Brown
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.,Iowa City Veterans Administration Medical Center, Iowa City, IA, USA.,Program in Free Radical and Radiation Biology, Department of Radiation Oncology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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9
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Bloomer SA, Moyer ED, Brown KE, Kregel KC. Aging results in accumulation of M1 and M2 hepatic macrophages and a differential response to gadolinium chloride. Histochem Cell Biol 2019; 153:37-48. [PMID: 31691025 DOI: 10.1007/s00418-019-01827-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 02/06/2023]
Abstract
Macrophages have vital roles in innate immunity by modulating the inflammatory response via their ability to alter their phenotype from pro-inflammatory (M1) to anti-inflammatory (M2). Aging increases activation of the innate immune system, and macrophage numbers increase in the aged liver. Since macrophages also produce free radical molecules, they are a potential source of age-related oxidative injury in the liver. This study evaluated macrophage phenotype in the aged liver and whether the increase in the number of macrophages with aging is associated with enhanced hepatic oxidative stress. Hepatic macrophage phenotype and oxidative stress were evaluated 2 days after a single intraperitoneal injection of saline or gadolinium chloride (GdCl3, 10 mg/kg) in young (6 months) and aged (24 months) Fischer 344 rats. GdCl3 has been shown to decrease the expression of macrophage-specific markers and impair macrophage phagocytosis in the liver. Saline-treated aged rats demonstrated greater numbers of both M1 (HO-1+/iNOS+) and M2 (HO-1+/CD163+) macrophages, without evidence of a phenotypic shift. GdCl3 did not alter levels of dihydroethidium fluorescence or malondialdehyde, suggesting that macrophages are not a major contributor to steady-state levels of oxidative stress. However, GdCl3 decreased M1 and M2 macrophage markers in both age groups, an effect that was attenuated in aged rats. In old animals, GdCl3 decreased iNOS expression to a greater extent than HO-1 or CD163. These results suggest a novel effect of aging on macrophage biology and that GdCl3 shifts hepatic macrophage polarization to the M2 phenotype in aged animals.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State University, Abington College, 1600 Woodland Rd., Abington, PA, 19001, USA.
| | - Eric D Moyer
- Division of Science and Engineering, Penn State University, Abington College, 1600 Woodland Rd., Abington, PA, 19001, USA
| | - Kyle E Brown
- Iowa City Veterans Administration Medical Center, Iowa City, IA, 52242, USA.,Division of Gastroenterology-Hepatology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, 52242, USA.,Program in Free Radical and Radiation Biology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Kevin C Kregel
- Department of Health and Human Physiology, The University of Iowa, Iowa City, IA, 52242, USA
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10
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Bloomer SA, Wellen KE, Henderson GC. Sexual dimorphism in the hepatic protein response to a moderate trans fat diet in senescence-accelerated mice. Lipids Health Dis 2017; 16:243. [PMID: 29237473 PMCID: PMC5729490 DOI: 10.1186/s12944-017-0639-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [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: 09/26/2017] [Accepted: 12/05/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Aging is characterized by increases in inflammation and oxidative stress, conditions that are exacerbated by environmental factors such as diet. In this study, we investigated the effects of a trans-fatty acid (TFA) diet on the liver in adult (25 wk) and old (60 wk) senescence-accelerated mice (SAMP8 strain) of both sexes. Our goal was to assess the effects of the diet on protein markers of inflammation and oxidative stress in the liver. METHODS Male and female mice were placed on life-long diets containing similar amounts of total fat (17%), with differing amounts of TFA: 2% (moderate TFA group) or 0.2% of total energy from TFA (control diet group). At the indicated ages, livers were harvested and evaluated for markers of inflammation and oxidative stress, as well as for enzymes of fat metabolism via immunoblotting. Relative densities of protein bands were determined and compared via a three-factor ANOVA. RESULTS Compared to males, females demonstrated significantly lower inflammatory protein expression (ICAM-1, MCP-1, COX-2), along with lower expression of the DNA damage marker, Gadd153, and the oxidative stress marker, HO-1. Female mice demonstrated higher expression of antioxidant enzymes (SOD-1, SOD-2, and Ref-1) and lipogenic enzymes (FASN, ACLY) compared to male mice. While HO-1 was elevated in the female mice fed the TFA diet compared to controls, the diet did not affect other markers of oxidative stress or inflammation. However, the diet was associated with significant increases in FASN and ACLY in adult (25 wk) male mice. CONCLUSIONS Our results suggest sexually dimorphic protein expression in the liver, with female mice demonstrating lower inflammation and increased oxidative stress defenses. Additionally, considering that FASN and ACLY contribute to hepatic lipogenesis, our results suggest a potential mechanism for the dyslipidemia in adult male mice that is associated with TFA diets.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State University, Abington College, 1600 Woodland Rd, Abington, PA, 19001, USA.
| | - Kathryn E Wellen
- Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.,Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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11
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Bloomer SA, Olivier AK, Bergmann OM, Mathahs MM, Broadhurst KA, Hicsasmaz H, Brown KE. Corrigendum: Strain- and time-dependent alterations in hepatic iron metabolism in a murine model of nonalcoholic steatohepatitis. Cell Biochem Funct 2017; 35:192-193. [PMID: 28436143 DOI: 10.1002/cbf.3261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, PA, USA
| | - Alicia K Olivier
- Division of Comparative Pathology, Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Pathobiology and Population Medicine, Mississippi State University, Starkville, MS, USA
| | - Ottar M Bergmann
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Internal Medicine, Section of Gastroenterology and Hepatology, The National University Hospital of Iceland, Reykjavik, Iceland
| | - M Meleah Mathahs
- Iowa City Veterans Administration Medical Center, Iowa City, IA, USA
| | | | | | - Kyle E Brown
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Administration Medical Center, Iowa City, IA, USA.,Program in Free Radical and Radiation Biology, Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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12
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Bloomer SA, Olivier AK, Bergmann OM, Mathahs MM, Broadhurst KA, Hicsasmaz H, Brown KE. Strain- and time-dependent alterations in hepatic iron metabolism in a murine model of nonalcoholic steatohepatitis. Cell Biochem Funct 2017; 34:628-639. [PMID: 27935134 DOI: 10.1002/cbf.3238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 01/29/2023]
Abstract
Nonalcoholic steatohepatitis is a common liver disease that is often accompanied by dysregulated iron metabolism. The aim of the study was to test the hypothesis that aberrant iron metabolism in nonalcoholic steatohepatitis is modulated by genetic susceptibility to inflammation and oxidative stress. Hepatic histology and iron content were assessed in 3 inbred strains of mice (C57BL/6, BALB/c, and C3H/HeJ) fed an atherogenic diet (AD). Hepatic expression of genes relevant to iron metabolism, inflammation, and oxidative stress were quantitated by real-time reverse transcription-polymerase chain reaction. At 6 weeks on the AD, histologic injury and induction of inflammatory and oxidative stress-associated gene expression were most pronounced in C57BL/6. At 18 weeks on the AD, these parameters were similar in C57BL/6 and BALB/c. Atherogenic diet-fed C3H/HeJ showed milder responses at both time points. The AD was associated with decreased hepatic iron concentrations in all strains at 6 and 18 weeks. The decrease in hepatic iron concentrations did not correlate with changes in hepcidin expression and was not associated with altered expression of iron transporters. These findings are similar to those observed in models of obesity-induced steatosis and indicate that hepatic steatosis can be associated with depletion of iron stores that is not explained by upregulation of hepcidin expression by inflammation. SIGNIFICANCE OF THE STUDY Nonalcoholic steatohepatitis (NASH) is a common liver disease that often accompanies the metabolic syndrome. The latter condition has been linked to iron deficiency and diminished intestinal iron absorption, likely the result of hepcidin upregulation by chronic inflammation. Paradoxically, some NASH patients accumulate excess hepatic iron, which may increase fibrosis and cancer risk. Iron accumulation has been attributed to suppression of hepcidin by oxidative stress. The objective of this study was to investigate the contributions of inflammation and oxidative stress to altered hepatic iron metabolism in a murine model of NASH using inbred strains of mice with differing susceptibilities to injury.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington, Abington, PA, USA
| | - Alicia K Olivier
- Division of Comparative Pathology, Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Pathobiology and Population Medicine, Mississippi State University, Starkville, MS, USA
| | - Ottar M Bergmann
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Internal Medicine, Section of Gastroenterology and Hepatology, The National University Hospital of Iceland, Reykjavik, Iceland
| | - M Meleah Mathahs
- Iowa City Veterans Administration Medical Center, Iowa City, IA, USA
| | | | | | - Kyle E Brown
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Administration Medical Center, Iowa City, IA, USA.,Program in Free Radical and Radiation Biology, Department of Radiation Oncology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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13
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Bloomer SA, Brown KE. Tumour promotion versus tumour suppression in chronic hepatic iron overload. Cell Biochem Funct 2015; 33:241-8. [DOI: 10.1002/cbf.3110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/25/2015] [Accepted: 03/26/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Steven A. Bloomer
- Division of Science and Engineering; Penn State Abington College; Abington PA USA
| | - Kyle E. Brown
- Iowa City Veterans Administration Medical Center; Iowa City IA USA
- Division of Gastroenterology-Hepatology; University of Iowa Roy J. and Lucille A. Carver College of Medicine; Iowa City IA USA
- Program in Free Radical and Radiation Biology; University of Iowa Roy J. and Lucille A. Carver College of Medicine; Iowa City IA USA
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14
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Sholomskas LM, Roche KL, Bloomer SA. Aging impairs induction of redox factor-1 after heat stress: a potential mechanism for heat-induced liver injury. Int J Physiol Pathophysiol Pharmacol 2015; 7:14-26. [PMID: 26069525 PMCID: PMC4446385] [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] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
Aging is associated with reduced tolerance to physiological stressors such as hyperthermia. In animal models, heat stress is associated with increased oxidative damage in the livers of old rats. In this study, we evaluated the expression of redox factor-1 (Ref-1), a DNA repair enzyme, and thioredoxin-1 (Trx-1), an antioxidant protein. We hypothesized that these proteins would be induced by heat stress in young animals, and that aging would attenuate this response. Young (6 mo) and old (24 mo) male Fischer 344 rats were exposed to a two-heat stress protocol, and livers were harvested at several time points after the second heat stress. Ref-1 and Trx-1 were evaluated by immunoblot and immunohistochemistry. In young rats, Ref-1 was induced by ~50% immediately (0 h) after heat stress, and returned to control levels at 2 h. We observed no change in Ref-1 after hyperthermia in old rats; however, aging was associated with a 2-fold increase in Ref-1 expression. At 2 h after heat stress, Trx-1 was increased in old rats, but there was no change in young rats. In tissue sections, we observed frequent ductular reactions in the old rats that were positive for both Ref-1 and Trx-1. The impairment in the induction of Ref-1 suggests a mechanism for the increased oxidative injury observed in old rats after heat stress. Furthermore, the observation of ductular reactions positive for both Ref-1 and Trx-1 demonstrates a proliferative cellular niche that develops with aging.
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Affiliation(s)
- Leslee M Sholomskas
- Division of Science and Engineering, Penn State Abington College Abington PA, 19001
| | - Kathryn L Roche
- Division of Science and Engineering, Penn State Abington College Abington PA, 19001
| | - Steven A Bloomer
- Division of Science and Engineering, Penn State Abington College Abington PA, 19001
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Bloomer SA, Kregel KC, Brown KE. Heat stress stimulates hepcidin mRNA expression and C/EBPα protein expression in aged rodent liver. Arch Gerontol Geriatr 2013; 58:145-52. [PMID: 23993269 DOI: 10.1016/j.archger.2013.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 07/08/2013] [Accepted: 07/30/2013] [Indexed: 02/08/2023]
Abstract
Elevations in hepatic iron content occur with aging and physiological stressors, which may promote oxidative injury to the liver. Since dysregulation of the iron regulatory hormone, hepcidin, can cause iron accumulation, our goal was to characterize the regulation of hepcidin in young (6 mo) and old (24 mo) Fischer 344 rats exposed to environmental heat stress. Liver and blood samples were taken in the control condition and after heating. Hepcidin expression did not differ between young and old rats in the control condition, despite higher levels of hepatic iron and IL-6 mRNA in the latter. Following heat stress, pSTAT3 increased in both groups, but C/EBPα and hepcidin mRNA increased only in old rats. Despite this, serum iron decreased in both age groups 2 h after heat stress, suggesting hepcidin-independent hypoferremia in the young rats. The differential regulation of hepcidin between young and old rats after hyperthermia may be due to the enhanced expression of C/EBPα protein in old rats. These data support the concept of "inflammaging" and suggest that repeated exposures to stressors may contribute to the development of anemia in older individuals.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington College, Abington, PA, United States; Department of Health and Human Physiology, The University of Iowa, Iowa City, IA 52242, United States.
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Bloomer SA, Han O, Kregel KC, Brown KE. Altered expression of iron regulatory proteins with aging is associated with transient hepatic iron accumulation after environmental heat stress. Blood Cells Mol Dis 2013; 52:19-26. [PMID: 23900040 DOI: 10.1016/j.bcmd.2013.07.002] [Citation(s) in RCA: 12] [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] [Received: 05/14/2013] [Revised: 06/24/2013] [Accepted: 07/02/2013] [Indexed: 01/24/2023]
Abstract
An increasing body of evidence suggests that dysregulation of iron metabolism contributes to age-related pathologies. We have previously observed increased hepatic iron with aging, and that environmental heat stress stimulates a further increase in iron and oxidative liver injury in old rats. The purpose of this study was to determine a mechanism for the increase in hepatic iron in old rats after heat stress. Young (6 mo) and old (24 mo) Fischer 344 rats were exposed to two heating bouts separated by 24 h. Livers were harvested after the second heat stress, and protein levels of the iron import protein, transferrin receptor-1 (TFR1), and the iron export protein, ferroportin (Fpn) were determined by immunoblot. In the nonheated condition, old rats had lower TFR1 expression, and higher Fpn expression. After heat stress, TFR1 declined in the old rats, and iron chelation studies demonstrated that this decline was dependent on a hyperthermia-induced increase in iron. TFR1 did not change in the young rats after heat stress. Since TFR1 is inversely regulated by iron, our results suggest that the increase in intracellular iron with aging and heat stress lower TFR1 expression. Fpn expression increased in both age groups after heat stress, but this response was delayed in old rats. This delay in the induction of an iron exporter suggests a mechanism for the increase in hepatic iron and oxidative injury after heat stress in aged organisms.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State Abington College, Abington, PA 19001, USA.
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Haak JL, Bloomer SA, Stauss HM, Liaboe FO, Kregel KC. Differential HSP expression between liver and quadriceps in response to chronic exertional heat stress. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.lb763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jodie L Haak
- Messiah CollegeMechanicsburgPA
- The University of IowaIowa CityIA
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Olsen AL, Bloomer SA, Chan EP, Gaça MDA, Georges PC, Sackey B, Uemura M, Janmey PA, Wells RG. Hepatic stellate cells require a stiff environment for myofibroblastic differentiation. Am J Physiol Gastrointest Liver Physiol 2011; 301:G110-8. [PMID: 21527725 PMCID: PMC3129929 DOI: 10.1152/ajpgi.00412.2010] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 04/26/2011] [Indexed: 01/31/2023]
Abstract
The myofibroblastic differentiation of hepatic stellate cells (HSC) is a critical event in liver fibrosis and is part of the final common pathway to cirrhosis in chronic liver disease from all causes. The molecular mechanisms driving HSC differentiation are not fully understood. Because macroscopic tissue stiffening is a feature of fibrotic disease, we hypothesized that mechanical properties of the underlying matrix are a principal determinant of HSC activation. Primary rat HSC were cultured on inert polyacrylamide supports of variable but precisely defined shear modulus (stiffness) coated with different extracellular matrix proteins or poly-L-lysine. HSC differentiation was determined by cell morphology, immunofluorescence staining, and gene expression. HSC became progressively myofibroblastic as substrate stiffness increased on all coating matrices, including Matrigel. The degree rather than speed of HSC activation correlated with substrate stiffness, with cells cultured on supports of intermediate stiffness adopting stable intermediate phenotypes. Quiescent cells on soft supports were able to undergo myofibroblastic differentiation with exposure to stiff supports. Stiffness-dependent differentiation required adhesion to matrix proteins and the generation of mechanical tension. Transforming growth factor-β treatment enhanced differentiation on stiff supports, but was not required. HSC differentiate to myofibroblasts in vitro primarily as a function of the physical rather than the chemical properties of the substrate. HSC require a mechanically stiff substrate, with adhesion to matrix proteins and the generation of mechanical tension, to differentiate. These findings suggest that alterations in liver stiffness are a key factor driving the progression of fibrosis.
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Affiliation(s)
- Abby L Olsen
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
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Bloomer SA, Kregel KC, Brown KE. Mechanisms of hepatic iron accumulation with aging and environmental heat stress. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1119.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bloomer SA, Cernak I, Haak JL, Kregel KC. Arimoclomol® enhances hepatic stress protein accumulation after an acute bout of heat stress. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.1000.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Ibolja Cernak
- National Security Technology Department, Biomedicine Business AreaJohns Hopkins University Applied Physics LaboratoryLaurelMD
| | - Jodie L Haak
- Integrative PhysiologyUniversity of IowaIowa CityIA
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Bloomer SA, Zhang HJ, Brown KE, Kregel KC. Differential regulation of hepatic heme oxygenase-1 protein with aging and heat stress. J Gerontol A Biol Sci Med Sci 2009; 64:419-25. [PMID: 19196643 DOI: 10.1093/gerona/gln056] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Increased expression of heme oxygenase-1 (HO-1) in response to physiological stress is considered to be a protective response, which may be altered with aging. In this study, HO-1 expression was assessed following heat stress by immunoblotting of liver homogenates and isolated hepatocytes from young (6 months) and old (24 months) Fischer 344 rats and by immunohistochemistry. Livers of old rats showed higher baseline levels of HO-1, which was predominately localized to Kupffer cells. After heat stress, young animals showed a greater relative increase in hepatic HO-1, part of which was caused by increased numbers of nonparenchymal cells that were immunoreactive to HO-1. Consistent with these data, HO-1 was significantly upregulated after hyperthermia in vitro only in hepatocytes from young rats. Hence, aging alters stress-induced expression of HO-1 in a cell-specific manner, which may contribute to the diminished stress tolerance observed in older organisms.
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Affiliation(s)
- Steven A Bloomer
- Department of Integrative Physiology, 532 FH, University of Iowa, Iowa City, IA 52242, USA
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Bloomer SA, Brown KE, Buettner GR, Kregel KC. Dysregulation of hepatic iron with aging: implications for heat stress-induced oxidative liver injury. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1165-74. [DOI: 10.1152/ajpregu.00719.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Environmental heat stress is associated with an age-related increase in hepatic oxidative damage and an exaggerated state of oxidative stress. The purpose of this investigation was to evaluate the regulation of hepatic iron after heat stress. A secondary aim was to determine a potential role for iron in heat stress-induced liver injury. Hyperthermia-induced alterations in hepatic iron were evaluated in young (6 mo) and old (24 mo) Fischer 344 rats by exposing them to a two-heat stress protocol. Livers were harvested at several time points after the second heating and assayed for labile and nonheme iron. In the control condition, there was no difference in labile iron between age groups. Both labile iron and storage iron were not altered by hyperthermia in young rats, but both were increased immediately after heating in old rats. To evaluate a role for iron in liver injury, hepatic iron content was manipulated in young and old rats, and then both groups were exposed to heat stress. Iron administration to young rats significantly increased hepatic iron content and ferritin but did not affect markers of lipid peroxidation under control conditions or after heat stress. In old rats, iron chelation with deferoxamine prevented the increase in nonheme iron, labile iron, ferritin, and lipid peroxidation after heat stress. These results suggest that iron may play a role in hepatic injury after hyperthermia. Thus, dysregulation of iron may contribute to the gradual decline in cellular and physiological function that occurs with aging.
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Bloomer SA, Brown KE, Buettner GR, Kregel KC. Dysregulation of hepatic iron with aging: implications for stress‐induced oxidative liver injury. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a815-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Steven A. Bloomer
- Integrative PhysiologyInternal Medicine, and Free Radical and Radiation Biology ProgramUniversity of Iowa424 Field HouseIowa CityIA52242
| | - Kyle E. Brown
- Integrative PhysiologyInternal Medicine, and Free Radical and Radiation Biology ProgramUniversity of Iowa424 Field HouseIowa CityIA52242
| | - Garry R. Buettner
- Integrative PhysiologyInternal Medicine, and Free Radical and Radiation Biology ProgramUniversity of Iowa424 Field HouseIowa CityIA52242
| | - Kevin C. Kregel
- Integrative PhysiologyInternal Medicine, and Free Radical and Radiation Biology ProgramUniversity of Iowa424 Field HouseIowa CityIA52242
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Butz CE, Bloomer SA, Brooks GA. DIABETES RESULTS IN AN INCREASE IN MCT1 CONCENTRATION IN THE RAT ERYTHROCYTE. Med Sci Sports Exerc 2003. [DOI: 10.1097/00005768-200305001-01178] [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: 11/25/2022]
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