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Zhang Q, Lang Y, Tang X, Cheng W, Cheng Z, Rizwan M, Xie L, Liu Y, Xu H, Liu Y. Polystyrene microplastic-induced endoplasmic reticulum stress contributes to growth plate endochondral ossification disorder in young rat. ENVIRONMENTAL TOXICOLOGY 2024; 39:3314-3329. [PMID: 38440912 DOI: 10.1002/tox.24182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 02/08/2024] [Accepted: 02/25/2024] [Indexed: 03/06/2024]
Abstract
BACKGROUND Previous studies on the effects of microplastics (MPs) on bone in early development are limited. This study aimed to investigate the adverse effects of MPs on bone in young rats and the potential mechanism. METHODS Three-week-old female rats were orally administered MPs for 28 days, and endoplasmic reticulum (ER) stress inhibitor salubrinal (SAL) and ER stress agonist tunicamycin (TM) were added to evaluate the effect of ER stress on toxicity of MPs. The indicators of growth and plasma markers of bone turnover were evaluated. Tibias were analyzed using micro-computed tomography (micro-CT). Histomorphological staining of growth plates was performed, and related gene expression of growth plate chondrocytes was tested. RESULTS After exposure of MPs, the rats had decreased growth, shortened tibial length, and altered blood calcium and phosphorus metabolism. Trabecular bone was sparse according to micro-CT inspection. In the growth plate, the thickness of proliferative zone substantial reduced while the thickness of hypertrophic zone increased significantly, and the chondrocytes were scarce and irregularly arranged according to tibial histological staining. The transcription of the ER stress-related genes BIP, PERK, ATF4, and CHOP dramatically increased, and the transcription factors involved in chondrocyte proliferation, differentiation, apoptosis, and matrix secretion were aberrant according to RT-qPCR and western blotting. Moreover, the addition of TM showed higher percentage of chondrocyte death. Administration of SAL alleviated all of the MPs-induced symptoms. CONCLUSION These results indicated that MPs could induce growth retardation and longitudinal bone damage in early development. The toxicity of MPs may attribute to induced ER stress and impaired essential processes of the endochondral ossification after MPs exposure.
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Affiliation(s)
- Qingqing Zhang
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Yuanyuan Lang
- Medical Imaging Center, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Xiaomin Tang
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Wenshu Cheng
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Zugen Cheng
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Mohammad Rizwan
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Lixin Xie
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Yanling Liu
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Hengyi Xu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
| | - Yang Liu
- Department of Pediatrics, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China
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Ji X, Hong J, Yang W, Yao M, Wang J, Jiang G, Wang Y, Li C, Lin J, Mou H, Li C, Li S, Chen Y, Shi M, Wang W, Lu F, Wu H, Zhao X, Qi Y, Yan S. GSTP1-mediated S-glutathionylation of Pik3r1 is a redox hub that inhibits osteoclastogenesis through regulating autophagic flux. Redox Biol 2023; 61:102635. [PMID: 36870110 PMCID: PMC9995948 DOI: 10.1016/j.redox.2023.102635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 02/11/2023] [Indexed: 03/03/2023] Open
Abstract
Glutathione S-transferase P1(GSTP1) is known for its transferase and detoxification activity. Based on disease-phenotype genetic associations, we found that GSTP1 might be associated with bone mineral density through Mendelian randomization analysis. Therefore, this study was performed both in vitro cellular and in vivo mouse model to determine how GSTP1 affects bone homeostasis. In our research, GSTP1 was revealed to upregulate the S-glutathionylation level of Pik3r1 through Cys498 and Cys670, thereby decreasing its phosphorylation, further controlling the alteration of autophagic flux via the Pik3r1-AKT-mTOR axis, and lastly altering osteoclast formation in vitro. In addition, knockdown and overexpression of GSTP1 in vivo also altered bone loss outcomes in the OVX mice model. In general, this study identified a new mechanism by which GSTP1 regulates osteoclastogenesis, and it is evident that the cell fate of osteoclasts is controlled by GSTP1-mediated S-glutathionylation via a redox-autophagy cascade.
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Affiliation(s)
- Xiaoxiao Ji
- Department of Orthopedic Surgery, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University School of Medicine, Yiwu, Zhejiang, PR China; Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Jianqiao Hong
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Weinan Yang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Minjun Yao
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Jie Wang
- Department of Orthopedic Surgery, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University School of Medicine, Yiwu, Zhejiang, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Guangyao Jiang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Yibo Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Congsun Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Jiyan Lin
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Haochen Mou
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Chaozhong Li
- College of Computer Science, Sichuan University, Chengdu, PR China
| | - Sihao Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Yazhou Chen
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Minming Shi
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Wei Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China
| | - Fei Lu
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China
| | - Haobo Wu
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China.
| | - Xiang Zhao
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China.
| | - Yiying Qi
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China.
| | - Shigui Yan
- Department of Orthopedic Surgery, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University School of Medicine, Yiwu, Zhejiang, PR China; Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, PR China; Orthopedics Research Institute of Zhejiang University, Hangzhou City, Zhejiang Province, PR China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, Hangzhou City, Zhejiang Province, PR China.
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Pan Y, Yang Y, Fan M, Chen C, Jiang R, Liang L, Xian M, Kuang B, Geng N, Feng N, Deng L, Zheng W, Zhang F, Li X, Guo F. Progranulin regulation of autophagy contributes to its chondroprotective effect in osteoarthritis. Genes Dis 2022. [DOI: 10.1016/j.gendis.2022.05.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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4
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Martin SA, Riordan RT, Wang R, Yu Z, Aguirre-Burk AM, Wong CP, Olson DA, Branscum AJ, Turner RT, Iwaniec UT, Perez VI. Rapamycin impairs bone accrual in young adult mice independent of Nrf2. Exp Gerontol 2021; 154:111516. [PMID: 34389472 DOI: 10.1016/j.exger.2021.111516] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/15/2021] [Accepted: 08/08/2021] [Indexed: 11/17/2022]
Abstract
Advanced age is the strongest risk factor for osteoporosis. The immunomodulator drug rapamycin extends lifespan in numerous experimental model organisms and is being investigated as a potential therapeutic to slow human aging, but little is known about the effects of rapamycin on bone. We evaluated the impact of rapamycin treatment on bone mass, architecture, and indices of bone turnover in healthy adult (16-20 weeks old at treatment initiation) female wild-type (ICR) and Nrf2-/- mice, a mouse model of oxidative damage and aging-related disease vulnerability. Rapamycin (4 mg/kg bodyweight) was administered by intraperitoneal injection every other day for 12 weeks. Mice treated with rapamycin exhibited lower femur bone mineral content, bone mineral density, and bone volume compared to vehicle-treated mice. In midshaft femur diaphysis (cortical bone), rapamycin-treated mice had lower cortical volume and thickness, and in the distal femur metaphysis (cancellous bone), rapamycin-treated mice had higher trabecular spacing and lower connectivity density. Mice treated with rapamycin exhibited lower bone volume, bone volume fraction, and trabecular thickness in the 5th lumbar vertebra. Rapamycin-treated mice had lower levels of bone formation in the distal femur metaphysis compared to vehicle-treated mice which occurred co-incidentally with increased serum CTX-1, a marker of global bone resorption. Rapamycin had no impact on tibia inflammatory cytokine gene expression, and we found no independent effects of Nrf2 knockout on bone, nor did we find any interactions between genotype and treatment. These data show that rapamycin may have a negative impact on the skeleton of adult mice that should not be overlooked in the clinical context of its usage as a therapy to retard aging and reduce the incidence of age-related pathologies.
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Affiliation(s)
- Stephen A Martin
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA; Biology of Aging Laboratory, Center for American Indian and Rural Health Equity, Montana State University, Bozeman, MT 59718, USA.
| | - Ruben T Riordan
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA; Department Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Rong Wang
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
| | - Zhen Yu
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
| | - Allan M Aguirre-Burk
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Carmen P Wong
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Dawn A Olson
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Adam J Branscum
- Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Russell T Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Urszula T Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Viviana I Perez
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA; Department Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
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5
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Abstract
PURPOSE OF REVIEW Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables. Bones grow in length by endochondral ossification in cartilaginous growth plates at ends of developing long bones. This review provides an updated overview of the important factors that influence this process. RECENT FINDINGS Insulin-like growth factor-1 (IGF-1) is the major hormone required for growth and a drug for treating pediatric skeletal disorders. Temperature is an underrecognized environmental variable that also impacts linear growth. This paper reviews the current state of knowledge regarding the interaction of IGF-1 and environmental factors on bone elongation. Understanding how internal and external variables regulate bone lengthening is essential for developing and improving treatments for an array of bone elongation disorders. Future studies may benefit from understanding how these unique relationships could offer realistic new approaches for increasing bone length in different growth-limiting conditions.
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Affiliation(s)
- Holly L Racine
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV, 26074, USA
| | - Maria A Serrat
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV, 25755, USA.
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, 25755, USA.
- Department of Orthopaedics, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, 25755, USA.
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6
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Maekawa H, Kawai S, Nishio M, Nagata S, Jin Y, Yoshitomi H, Matsuda S, Toguchida J. Prophylactic treatment of rapamycin ameliorates naturally developing and episode -induced heterotopic ossification in mice expressing human mutant ACVR1. Orphanet J Rare Dis 2020; 15:122. [PMID: 32448372 PMCID: PMC7245788 DOI: 10.1186/s13023-020-01406-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 05/11/2020] [Indexed: 11/10/2022] Open
Abstract
Background Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal-dominant disease characterized by heterotopic ossification (HO) in soft tissues and caused by a mutation of the ACVR1A/ALK2 gene. Activin-A is a key molecule for initiating the process of HO via the activation of mTOR, while rapamycin, an mTOR inhibitor, effectively inhibits the Activin-A-induced HO. However, few reports have verified the effect of rapamycin on FOP in clinical perspectives. Methods We investigated the effect of rapamycin for different clinical situations by using mice conditionally expressing human mutant ACVR1A/ALK2 gene. We also compared the effect of rapamycin between early and episode-initiated treatments for each situation. Results Continuous, episode-independent administration of rapamycin reduced the incidence and severity of HO in the natural course of FOP mice. Pinch-injury induced HO not only at the injured sites, but also in the contralateral limbs and provoked a prolonged production of Activin-A in inflammatory cells. Although both early and injury-initiated treatment of rapamycin suppressed HO in the injured sites, the former was more effective at preventing HO in the contralateral limbs. Rapamycin was also effective at reducing the volume of recurrent HO after the surgical resection of injury-induced HO, for which the early treatment was more effective. Conclusion Our study suggested that prophylactic treatment will be a choice of method for the clinical application of rapamycin for FOP.
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Affiliation(s)
- Hirotsugu Maekawa
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan.,Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shunsuke Kawai
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan.,Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Regeneration Sciences and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Megumi Nishio
- Department of Regeneration Sciences and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Sanae Nagata
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Yonghui Jin
- Department of Regeneration Sciences and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Institute for Advancement of Clinical and Translational Sciences, Kyoto University Hospital, Kyoto University, Kyoto, Japan
| | - Hiroyuki Yoshitomi
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Regeneration Sciences and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shuichi Matsuda
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Junya Toguchida
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan. .,Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. .,Department of Regeneration Sciences and Engineering, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan. .,Institute for Advancement of Clinical and Translational Sciences, Kyoto University Hospital, Kyoto University, Kyoto, Japan.
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7
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Fuente R, Gil-Peña H, Claramunt-Taberner D, Hernández-Frías O, Fernández-Iglesias Á, Alonso-Durán L, Rodríguez-Rubio E, Hermida-Prado F, Anes-González G, Rubio-Aliaga I, Wagner C, Santos F. MAPK inhibition and growth hormone: a promising therapy in XLH. FASEB J 2019; 33:8349-8362. [DOI: 10.1096/fj.201802007r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Rocío Fuente
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
- Department of Developmental BiologyHarvard School of Dental MedicineHarvard University Boston Massachusetts USA
| | - Helena Gil-Peña
- Department of PediatricsHospital Universitario Central de Asturias Oviedo Spain
| | - Débora Claramunt-Taberner
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
| | - Olaya Hernández-Frías
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
| | - Ángela Fernández-Iglesias
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
| | - Laura Alonso-Durán
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
| | - Enrique Rodríguez-Rubio
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
| | - Francisco Hermida-Prado
- Department of OtorhinolaryngologyHospital Universitario Central de AsturiasInstituto Universitario de Oncología del Principado de Asturias Oviedo Spain
| | | | - Isabel Rubio-Aliaga
- Kidney and Acid-Base Physiology GroupInstitute of PhysiologyUniversity of Zurich Zurich Switzerland
| | - Carsten Wagner
- Kidney and Acid-Base Physiology GroupInstitute of PhysiologyUniversity of Zurich Zurich Switzerland
| | - Fernando Santos
- Division of PediatricsDepartment of MedicineFaculty of Medicine and Health SciencesUniversity of Oviedo Oviedo Spain
- Department of PediatricsHospital Universitario Central de Asturias Oviedo Spain
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Fuente R, Gil-Peña H, Claramunt-Taberner D, Hernández-Frías O, Fernández-Iglesias Á, Hermida-Prado F, Anes-González G, Rubio-Aliaga I, Lopez JM, Santos F. Marked alterations in the structure, dynamics and maturation of growth plate likely explain growth retardation and bone deformities of young Hyp mice. Bone 2018; 116:187-195. [PMID: 30096468 DOI: 10.1016/j.bone.2018.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/02/2018] [Accepted: 08/07/2018] [Indexed: 12/11/2022]
Abstract
Mechanisms underlying growth impairment and bone deformities in X-linked hypophosphatemia are not fully understood. We here describe marked alterations in the structure, dynamics and maturation of growth plate in growth-retarded young Hyp mice, in comparison with wild type mice. Hyp mice exhibited reduced proliferation and apoptosis rates of chondrocytes as well as severe disturbance in the process of chondrocyte hypertrophy disclosed by abnormal expression of proteins likely involved in cell enlargement, irregular chondro-osseous junction and disordered bone trabecular pattern and vascular invasion in the primary spongiosa. (Hyp mice had elevated circulating FGF23 levels and over activation of ERK in the growth plate.) All these findings provide a basis to explain growth impairment and metaphyseal deformities in XLH. Hyp mice were compared with wild type mice serum parameters, nutritional status and growth impairment by evaluation of growth cartilage and bone structures. Hyp mice presented hyphosphatemia with high FGF23 levels. Weight gain and longitudinal growth resulted reduced in them with numerous skeletal abnormalities at cortical bone. It was also observed aberrant trabecular organization at primary spongiosa and atypical growth plate organization with abnormal proliferation and hypertrophy of chondrocytes and diminished apoptosis and vascular invasion processes. The present results show for the first time the abnormalities present in the growth plate of young Hyp mice and suggest that both cartilage and bone alterations may be involved in the growth impairment and the long bone deformities of XLH.
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Affiliation(s)
- Rocío Fuente
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain; Harvard School of Dental Medicine, Developmental Biology, Harvard University, Boston, MA, USA
| | - Helena Gil-Peña
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain.
| | - Débora Claramunt-Taberner
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain
| | - Olaya Hernández-Frías
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain
| | - Ángela Fernández-Iglesias
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain
| | - Francisco Hermida-Prado
- Department of Otolaryngologist, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Oviedo, Spain
| | - Gonzalo Anes-González
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain
| | - Isabel Rubio-Aliaga
- University of Zurich, Institute of Physiology, Kidney and Acid-base Physiology Group, Zurich, Switzerland
| | - Jose Manuel Lopez
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain
| | - Fernando Santos
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, Oviedo, Asturias, Spain; Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain
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9
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Vanderstraeten J, Derradji H, Sonveaux P, Colin IM, Many MC, Gérard AC. Acute iodine deficiency induces a transient VEGF-dependent microvascular response in mammary glands involving HIF-1, ROS, and mTOR. Am J Physiol Cell Physiol 2018; 315:C544-C557. [PMID: 30020826 DOI: 10.1152/ajpcell.00095.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Iodine deficiency (ID), which affects almost two billion people worldwide, is associated with breast pathologies such as fibrosis in human and induces breast atypia in animal models. Because ID induces vascular activation in the thyroid, another iodide-uptaking organ, and as breast is also sensitive to ID, we aimed to characterize ID-induced effects on the breast microvasculature in vivo and in two different breast cell lines in vitro. Virgin and lactating NMRI mice received an iodide-deficient diet and a Na+/I- symporter inhibitor for 1 to 20 days. Some virgin mice were treated with vascular endothelial growth factor A (VEGF) or VEGF receptor inhibitors. In vitro, ID was induced in MCF7 and MCF12A cells by replacing the iodide-containing medium by an iodide-deficient medium. In vivo, VEGF expression was increased following ID in mammary tissues. Consequently, ID induced a transient increase in mammary gland blood flow, measured after anesthesia, in virgin and lactating mice, which was repressed by VEGF or VEGF receptor inhibitors. In MCF7 cells, ID induced a transient increase in reactive oxygen species, followed by an increase in hypoxia-inducible factor-1α (HIF-1α) protein and VEGF mRNA expression. Antioxidant N-acetylcysteine and mammalian target of rapamycin (mTOR) inhibitor blocked ID-induced HIF-1α protein increase and VEGF transcription. However, mTOR activity was not inhibited by N-acetylcysteine. Similar responses were observed in MCF12A cells. These data indicate that ID activates the canonical VEGF pathway and mTOR in breast tissues, which provides new insights to better understand the correlation between ID, vascular activation, and breast pathologies.
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Affiliation(s)
- Jessica Vanderstraeten
- Pole of Morphology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain , Brussels , Belgium
| | - Hanane Derradji
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium
| | - Pierre Sonveaux
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain , Brussels , Belgium
| | - Ides M Colin
- Service d'Endocrino-Diabétologie, Centre Hospitalier Régional, Mons-Hainaut, Belgium
| | - Marie-Christine Many
- Pole of Morphology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain , Brussels , Belgium
| | - Anne-Catherine Gérard
- Service d'Endocrino-Diabétologie, Centre Hospitalier Régional, Mons-Hainaut, Belgium
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Ouyang J, Jiang H, Fang H, Cui W, Cai D. Isoimperatorin ameliorates osteoarthritis by downregulating the mammalian target of rapamycin C1 signaling pathway. Mol Med Rep 2017; 16:9636-9644. [DOI: 10.3892/mmr.2017.7777] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 06/29/2017] [Indexed: 11/05/2022] Open
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Shen G, Ren H, Qiu T, Zhang Z, Zhao W, Yu X, Huang J, Tang J, Liang D, Yao Z, Yang Z, Jiang X. Mammalian target of rapamycin as a therapeutic target in osteoporosis. J Cell Physiol 2017; 233:3929-3944. [PMID: 28834576 DOI: 10.1002/jcp.26161] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022]
Abstract
The mechanistic target of rapamycin (mTOR) plays a key role in sensing and integrating large amounts of environmental cues to regulate organismal growth, homeostasis, and many major cellular processes. Recently, mounting evidences highlight its roles in regulating bone homeostasis, which sheds light on the pathogenesis of osteoporosis. The activation/inhibition of mTOR signaling is reported to positively/negatively regulate bone marrow mesenchymal stem cells (BMSCs)/osteoblasts-mediated bone formation, adipogenic differentiation, osteocytes homeostasis, and osteoclasts-mediated bone resorption, which result in the changes of bone homeostasis, thereby resulting in or protect against osteoporosis. Given the likely importance of mTOR signaling in the pathogenesis of osteoporosis, here we discuss the detailed mechanisms in mTOR machinery and its association with osteoporosis therapy.
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Affiliation(s)
- Gengyang Shen
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hui Ren
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Ting Qiu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhida Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenhua Zhao
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiang Yu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jinjing Huang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jingjing Tang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - De Liang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhensong Yao
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhidong Yang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaobing Jiang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Laboratory Affiliated to National Key Discipline of Orthopaedic and Traumatology of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
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12
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Pharmacological modulation of autophagy: therapeutic potential and persisting obstacles. Nat Rev Drug Discov 2017; 16:487-511. [PMID: 28529316 DOI: 10.1038/nrd.2017.22] [Citation(s) in RCA: 589] [Impact Index Per Article: 84.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autophagy is central to the maintenance of organismal homeostasis in both physiological and pathological situations. Accordingly, alterations in autophagy have been linked to clinically relevant conditions as diverse as cancer, neurodegeneration and cardiac disorders. Throughout the past decade, autophagy has attracted considerable attention as a target for the development of novel therapeutics. However, such efforts have not yet generated clinically viable interventions. In this Review, we discuss the therapeutic potential of autophagy modulators, analyse the obstacles that have limited their development and propose strategies that may unlock the full therapeutic potential of autophagy modulation in the clinic.
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Chondrocyte-Specific Knockout of TSC-1 Leads to Congenital Spinal Deformity in Mice. BIOMED RESEARCH INTERNATIONAL 2017; 2017:8215805. [PMID: 28523278 PMCID: PMC5420956 DOI: 10.1155/2017/8215805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/13/2017] [Indexed: 11/17/2022]
Abstract
Congenital spinal deformity is the most severe clinical orthopedic issue worldwide. Among all the pathological processes of congenital spinal deformity, the imbalance of endochondral ossification is considered to be the most important developmental cause of spinal dysplasia. We established chondrocyte-specific TSC-1 knockout (KO) mice to overactivate the energy metabolic component, mammalian target of rapamycin complex 1 (mTORC1), and measured the spinal development by general, imaging, histological, and Western-blot assessments. In addition to skeletal dysplasia, the KO mice displayed severe congenital spinal deformity and significant intervertebral disc changes. This study suggests that, in the process of endochondral ossification, excessive activation of mTORC1 signaling in chondrocytes induces obvious spinal deformity, and the chondrocytes may be the cell type responsible for congenital spinal deformity.
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Shen G, Ren H, Qiu T, Liang D, Xie B, Zhang Z, Yao Z, Yang Z, Jiang X. Implications of the Interaction Between miRNAs and Autophagy in Osteoporosis. Calcif Tissue Int 2016; 99:1-12. [PMID: 26922423 DOI: 10.1007/s00223-016-0122-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 02/15/2016] [Indexed: 01/08/2023]
Abstract
Imbalances between bone formation and resorption are the primary cause of osteoporosis. However, currently, a detailed molecular mechanism of osteoporosis is not available. Autophagy is the conserved process characterized by degrading and recycling aggregated proteins, intracellular pathogens, and damaged organelles. MicroRNAs (miRNAs) are novel regulatory factors that play important roles in numerous cellular processes, including autophagy, through the posttranscriptional regulation of gene expression. Conversely, autophagy plays a role in the regulation of miRNA homeostasis. Recent advances have revealed that both autophagy and miRNAs are involved in the maintenance of bone homoeostasis, whereas the role of the interaction of miRNAs with autophagy in osteoporosis remains unclear. In this paper, we review previous reports on autophagy, miRNAs, and their interaction in osteoporosis.
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Affiliation(s)
- Gengyang Shen
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Hui Ren
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Ting Qiu
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - De Liang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Bo Xie
- The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhida Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhensong Yao
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhidong Yang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Xiaobing Jiang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
- Laboratory Affiliated to National Key Discipline of Orthopaedic and Traumatology of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
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15
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Cheng NT, Guo A, Cui YP. Intra-articular injection of Torin 1 reduces degeneration of articular cartilage in a rabbit osteoarthritis model. Bone Joint Res 2016; 5:218-24. [PMID: 27301478 PMCID: PMC4921044 DOI: 10.1302/2046-3758.56.bjr-2015-0001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/17/2016] [Indexed: 01/22/2023] Open
Abstract
Objectives Recent studies have shown that systemic injection of rapamycin can prevent the development of osteoarthritis (OA)-like changes in human chondrocytes and reduce the severity of experimental OA. However, the systemic injection of rapamycin leads to many side effects. The purpose of this study was to determine the effects of intra-articular injection of Torin 1, which as a specific inhibitor of mTOR which can cause induction of autophagy, is similar to rapamycin, on articular cartilage degeneration in a rabbit osteoarthritis model and to investigate the mechanism of Torin 1’s effects on experimental OA. Methods Collagenase (type II) was injected twice into both knees of three-month-old rabbits to induce OA, combined with two intra–articular injections of Torin 1 (400 nM). Degeneration of articular cartilage was evaluated by histology using the Mankin scoring system at eight weeks after injection. Chondrocyte degeneration and autophagosomes were observed by transmission electron microscopy. Matrix metallopeptidase-13 (MMP-13) and vascular endothelial growth factor (VEGF) expression were analysed by quantitative RT-PCR (qPCR).Beclin-1 and light chain 3 (LC3) expression were examined by Western blotting. Results Intra-articular injection of Torin 1 significantly reduced degeneration of the articular cartilage after induction of OA. Autophagosomes andBeclin-1 and LC3 expression were increased in the chondrocytes from Torin 1-treated rabbits. Torin 1 treatment also reduced MMP-13 and VEGF expression at eight weeks after collagenase injection. Conclusion Our results demonstrate that intra-articular injection of Torin 1 reduces degeneration of articular cartilage in collagenase-induced OA, at least partially by autophagy activation, suggesting a novel therapeutic approach for preventing cartilage degeneration and treating OA. Cite this article: N-T. Cheng, A. Guo, Y-P. Cui. Intra-articular injection of Torin 1 reduces degeneration of articular cartilage in a rabbit osteoarthritis model. Bone Joint Res 2016;5:218–224. DOI: 10.1302/2046-3758.56.BJR-2015-0001.
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Affiliation(s)
- N-T Cheng
- Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xi-Cheng District, Beijing 100050, China
| | - A Guo
- Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xi-Cheng District, Beijing 100050, China
| | - Y-P Cui
- Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xi-Cheng District, Beijing 100050, China
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Nel JD, Epstein S. Metabolic Bone Disease in the Post-transplant Population: Preventative and Therapeutic Measures. Med Clin North Am 2016; 100:569-86. [PMID: 27095646 DOI: 10.1016/j.mcna.2016.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Post-transplant bone disease contributes significantly to patients' morbidity and mortality after transplantation and has an impact on their quality of life. This article discusses the major contributors to mechanisms causing bone loss, highlighting the role of preexisting disease in both kidney and liver failure and contributions from glucocorticoids and calcineurin inhibitors. Suggested monitoring and investigations are reviewed as well as treatment as far as the current literature supports, emphasizing the difference between kidney and liver recipients.
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Affiliation(s)
- Johan Daniël Nel
- Division of Nephrology, Department of Medicine, Tygerberg Hospital and University of Stellenbosch, PO Box 241, Cape Town, Western Cape 8000, South Africa.
| | - Sol Epstein
- Mt Sinai School of Medicine, New York, NY, USA; University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Wong J, Tan MZW, Chandran M. Fifty shades of gray: Bone disease in renal transplantation. PROCEEDINGS OF SINGAPORE HEALTHCARE 2015. [DOI: 10.1177/2010105815611808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Kidney transplantation is the renal replacement therapy of choice for patients with end stage renal disease. Advances in technology, surgical techniques and pharmacotherapy have improved renal allograft survival. Increasingly, we are seeing long term side effects related to renal transplantation, bone disease being a major one amongst them. Renal transplant patients have a higher risk of fragility fractures even when compared to those who remain on dialysis. This is likely to be related to pre-existing underlying bone disease and the emergence of new metabolic bone problems post-transplant. Conditions such as persistent hyperparathyroidism and the use of certain immunosuppressive agents have a deleterious effect on the post renal transplant bone. Remarkable advances in the field of metabolic bone research have been made in the last decade and newer imaging techniques, biomarkers and therapeutic options are now available for osteoporosis in the general population. Interest is being focused on attempting to extrapolate these new discoveries to the management of bone disease post renal transplant. This review will briefly describe the metabolic bone changes that occur after transplantation and will provide an update on the currently available investigative options and therapeutic strategies for the management of post renal transplant bone disease.
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Affiliation(s)
- Jiunn Wong
- Department of Renal Medicine, Singapore General Hospital, Singapore
| | | | - Manju Chandran
- Department of Endocrinology, Singapore General Hospital, Singapore
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Goodman CA, Hornberger TA, Robling AG. Bone and skeletal muscle: Key players in mechanotransduction and potential overlapping mechanisms. Bone 2015; 80:24-36. [PMID: 26453495 PMCID: PMC4600534 DOI: 10.1016/j.bone.2015.04.014] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 03/18/2015] [Accepted: 04/07/2015] [Indexed: 12/16/2022]
Abstract
The development and maintenance of skeletal muscle and bone mass is critical for movement, health and issues associated with the quality of life. Skeletal muscle and bone mass are regulated by a variety of factors that include changes in mechanical loading. Moreover, bone mass is, in large part, regulated by muscle-derived mechanical forces and thus by changes in muscle mass/strength. A thorough understanding of the cellular mechanism(s) responsible for mechanotransduction in bone and skeletal muscle is essential for the development of effective exercise and pharmaceutical strategies aimed at increasing, and/or preventing the loss of, mass in these tissues. Thus, in this review we will attempt to summarize the current evidence for the major molecular mechanisms involved in mechanotransduction in skeletal muscle and bone. By examining the differences and similarities in mechanotransduction between these two tissues, it is hoped that this review will stimulate new insights and ideas for future research and promote collaboration between bone and muscle biologists.(1).
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Affiliation(s)
- Craig A Goodman
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA; Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne, Australia; Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.
| | - Troy A Hornberger
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alexander G Robling
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Roudebush Veterans Affairs Medical Center, Indianapolis, IN 46202, USA; Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA
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The consequences of pediatric renal transplantation on bone metabolism and growth. Curr Opin Organ Transplant 2015; 18:555-62. [PMID: 23995376 DOI: 10.1097/mot.0b013e3283651b21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW During childhood, growth retardation, decreased final height and renal osteodystrophy are common complications of chronic kidney disease (CKD). These problems remain present in patients undergoing renal transplantation, even though steroid-sparing strategies are more widely used. In this context, achieving normal height and growth in children after transplantation is a crucial issue for both quality of life and self-esteem. The aim of this review is to provide an overview of pathophysiology of CKD-mineral bone disorder (MBD) in children undergoing renal transplantation and to propose keypoints for its daily management. RECENT FINDINGS In adults, calcimimetics are effective for posttransplant hyperparathyroidism, but data are missing in the pediatric population. Fibroblast growth factor 23 levels are associated with increased risk of rejection, but the underlying mechanisms remain unclear. A recent meta-analysis also demonstrated the effectiveness of rhGH therapy in short transplanted children. SUMMARY In 2013, the daily clinical management of CKD-MBD in transplanted children should still focus on simple objectives: to optimize renal function, to develop and promote steroid-sparing strategies, to provide optimal nutritional support to maximize final height and avoid bone deformations, to equilibrate calcium/phosphate metabolism so as to provide acceptable bone quality and cardiovascular status, to correct all metabolic and clinical abnormalities that can worsen both bone and growth (mainly metabolic acidosis, anemia and malnutrition), promote good lifestyle habits (adequate calcium intake, regular physical activity, no sodas consumption, no tobacco exposure) and eventually to correct native vitamin D deficiency (target of 25-vitamin D >75 nmol/l).
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Abstract
Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the progressive loss of articular cartilage, remodeling of the subchondral bone, and synovial inflammation. Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that controls critical cellular processes such as growth, proliferation, and protein synthesis. Recent studies suggest that mTOR plays a vital role in cartilage growth and development and in altering the articular cartilage homeostasis as well as contributing to the process of cartilage degeneration associated with OA. Both pharmacological inhibition and genetic deletion of mTOR have been shown to reduce the severity of OA in preclinical mouse models. In this review article, we discuss the roles of mTOR in cartilage development, in maintaining articular cartilage homeostasis, and its potential as an OA therapeutic target.
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Affiliation(s)
- Bandna Pal
- Division of Genetics and Development, The Toronto Western Research Institute, Toronto Western Hospital, The University Health Network (UHN), 60 Leonard Avenue, Toronto, ON M5T 2S8 Canada
| | - Helal Endisha
- Division of Genetics and Development, The Toronto Western Research Institute, Toronto Western Hospital, The University Health Network (UHN), 60 Leonard Avenue, Toronto, ON M5T 2S8 Canada
| | - Yue Zhang
- Division of Genetics and Development, The Toronto Western Research Institute, Toronto Western Hospital, The University Health Network (UHN), 60 Leonard Avenue, Toronto, ON M5T 2S8 Canada
| | - Mohit Kapoor
- Division of Genetics and Development, The Toronto Western Research Institute, Toronto Western Hospital, The University Health Network (UHN), 60 Leonard Avenue, Toronto, ON M5T 2S8 Canada
- Department of Surgery, University of Toronto, Toronto, ON Canada
- Division of Orthopaedics, Toronto Western Hospital, Toronto, ON Canada
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Takayama K, Kawakami Y, Kobayashi M, Greco N, Cummins JH, Matsushita T, Kuroda R, Kurosaka M, Fu FH, Huard J. Local intra-articular injection of rapamycin delays articular cartilage degeneration in a murine model of osteoarthritis. Arthritis Res Ther 2014; 16:482. [PMID: 25403236 PMCID: PMC4269094 DOI: 10.1186/s13075-014-0482-4] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 11/05/2014] [Indexed: 02/07/2023] Open
Abstract
Introduction Recent studies have revealed that rapamycin activates autophagy in human chondrocytes preventing the development of osteoarthritis (OA) like changes in vitro, while the systemic injection of rapamycin reduces the severity of experimental osteoarthritis in a murine model of OA in vivo. Since the systemic use of rapamycin is associated with numerous side effects, the goal of the current study was to examine the beneficial effect of local intra-articular injection of rapamycin in a murine model of OA and to elucidate the mechanism of action of rapamycin on articular cartilage. Methods Destabilization of the medial meniscus (DMM) was performed on 10-week-old male mice to induce OA. Intra-articular injections of 10 μl of rapamycin (10 μM) were administered twice weekly for 8 weeks. Articular cartilage damage was analyzed by histology using a semi-quantitative scoring system at 8 and 12 weeks after surgery. Mammalian target of rapamycin (mTOR), light chain 3 (LC3), vascular endothelial growth factor (VEGF), collagen, type X alpha 1 (COL10A1), and matrix metallopeptidase 13 (MMP13) expressions were analyzed by immunohistochemistry. VEGF, COL10A1, and MMP13 expressions were further examined via quantitative RT-PCR (qPCR). Results Intra-articular injection of rapamycin significantly reduced the severity of articular cartilage degradation at 8 and 12 weeks after DMM surgery. A reduction in mTOR expression and the activation of LC3 (an autophagy marker) in the chondrocytes was observed in the rapamycin treated mice. Rapamycin treatment also reduced VEGF, COL10A1, and MMP13 expressions at 8 and 12 weeks after DMM surgery. Conclusion These results demonstrate that the intra-articular injection of rapamycin could reduce mTOR expression, leading to a delay in articular cartilage degradation in our OA murine model. Our observations suggest that local intra-articular injection of rapamycin could represent a potential therapeutic approach to prevent OA.
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Blaslov K, Katalinic L, Kes P, Spasovski G, Smalcelj R, Basic-Jukic N. What is the impact of immunosuppressive treatment on the post-transplant renal osteopathy? Int Urol Nephrol 2013; 46:1019-24. [PMID: 24217803 DOI: 10.1007/s11255-013-0596-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/22/2013] [Indexed: 10/26/2022]
Abstract
Although glucocorticoid therapy is considered to be the main pathogenic factor, a consistent body of evidence suggests that other immunosuppressants might also play an important role in the development of the post-transplant renal osteopathy (PRO) through their pleiotropic pharmacological effects. Glucocorticoids seem to induce osteoclasts' activity suppressing the osteoblasts while data regarding other immunosuppressive drugs are still controversial. Mycophenolate mofetil and azathioprine appear to be neutral regarding the bone metabolism. However, the study analyzing any independent effect of antimetabolites on bone turnover has not been conducted yet. Calcineurin inhibitors (CNIs) induce trabecular bone loss in rodent, with contradictory results in renal transplant recipients. Suppression of vitamin D receptor is probably the underlying mechanism of renal calcium wasting in renal transplant recipients receiving CNI. In spite of an increased 1,25(OH)2 vitamin D level, the kidney is not able to reserve calcium, suggesting a role of vitamin D resistance that may be related to bone loss. More efforts should be invested to determine the role of CNI in PRO. In particular, data regarding the role of mammalian target of rapamycin inhibitors (mTORi), such as sirolimus and everolimus, in the PRO development are still controversial. Rapamycin markedly decreases bone longitudinal growth as well as callus formation in experimental models, but also lowers the rate of bone resorption markers and glomerular filtration in clinical studies. Everolimus potently inhibits primary mouse and human osteoclast activity as well as the osteoclast differentiation. It also prevents the ovariectomy-induced loss of cancellous bone by 60 %, an effect predominantly associated with a decreased osteoclast-mediated bone resorption, resulting in a partial preservation of the cancellous bone. At present, there is no clinical study analyzing the effect of everolimus on bone turnover in renal transplant recipients or comparing sirolimus versus everolimus impact on bone, so only general conclusions could be drawn. Hence, the use of mTORi might be useful in patients with PRO due to their possible potential to inhibit osteoclast activity which might lead to a decreased rate of bone resorption. In addition, it should be also emphasized that they might inhibit osteoblast activity which may lead to a decreased bone formation and adynamic bone disease. Further studies are urgently needed to solve these important clinical dilemmas.
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Affiliation(s)
- Kristina Blaslov
- Department of Nephrology, Arterial Hypertension, Dialysis and Transplantation, University Hospital Centre Zagreb, Kispaticeva 12, 10000, Zagreb, Croatia
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[Mineral and bone disorders in renal transplantation]. Nephrol Ther 2013; 9:461-70. [PMID: 24176653 DOI: 10.1016/j.nephro.2013.07.372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 07/23/2013] [Accepted: 07/26/2013] [Indexed: 11/22/2022]
Abstract
The deregulation of bone and mineral metabolism during chronic kidney disease (CKD) is a daily challenge for physicians, its management aiming at decreasing the risk of both fractures and vascular calcifications. Renal transplantation in the context of CKD, with pre-existing renal osteodystrophy as well as nutritional impairment, chronic inflammation, hypogonadism and corticosteroids exposure, represents a major risk factor for bone impairment in the post-transplant period. The aim of this review is therefore to provide an update on the pathophysiology of mineral and bone disorders after renal transplantation.
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Billing H, Burmeister G, Plotnicki L, Ahlenstiel T, Fichtner A, Sander A, Höcker B, Tönshoff B, Pape L. Longitudinal growth on an everolimus- versus an MMF-based steroid-free immunosuppressive regimen in paediatric renal transplant recipients. Transpl Int 2013; 26:903-9. [PMID: 23865768 DOI: 10.1111/tri.12148] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/13/2013] [Accepted: 06/14/2013] [Indexed: 01/30/2023]
Abstract
Concerns have been raised that mammalian target of rapamycin inhibitors in pediatric transplant recipients might interfere with longitudinal bone growth by inhibition of growth factor signaling and growth plate chondrocyte proliferation. We therefore undertook a prospective nested, case-control study on longitudinal growth over 2 years in steroid-free pediatric renal transplant recipients. Fourteen patients on a steroid-free maintenance immunosuppressive regimen consisting of low-dose everolimus (EVR) in conjunction with low-dose cyclosporine (CsA) were compared to a matched cohort of 14 steroid-free patients on a standard dose mycophenolate mofetil (MMF) regimen in conjunction with a standard dose calcineurin inhibitor (CNI). The mean change in height standard deviation (SD) score in the first study year was 0.31 ± 0.71 SD score in the EVR group compared to 0.31 ± 0.64 SD score in the MMF group (P = 0.20). For the entire study period of 2 years, the change in height SD score in the EVR group was 0.43 ± 0.81 SDS compared to 0.75 ± 0.85 SDS in the MMF group (P = 0.32). The percentage of prepubertal patients experiencing catch-up growth, defined as an increase in height SD score ≥0.5 in 2 years, was similar in the EVR group (5/8, 65%) and the MMF group (6/8, 75%; P = 1.00). Longitudinal growth over 2 years in steroid-free pediatric patients on low-dose EVR and CsA is not different to that of a matched steroid-free control group on an immunosuppressive regimen with standard-dose CNI and MMF. Hence, low-dose EVR does not appear to negatively impact short-term growth in pediatric renal transplant recipients.
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Affiliation(s)
- Heiko Billing
- Department of Paediatrics I, University Children's Hospital, Heidelberg, Germany
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Monteverde ML, Ibañez J, Balbarrey Z, Chaparro A, Diaz M, Turconi A. Conversion to sirolimus in pediatric renal transplant patients: a single-center experience. Pediatr Transplant 2012; 16:582-8. [PMID: 22533794 DOI: 10.1111/j.1399-3046.2012.01697.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We studied efficacy and safety of conversion from CNI- to SRL-based immunosuppression in 92 kidney TX recipients, mainly due to CAN (69%). Median time of conversion was 31 months (r: 0.3-165); median time of follow-up: 36 months (r: 2-102). In the whole group mean eGFR increased from 53 ± 22 to 67 ± 26mL/min/1.73 m(2) at three months (p = 0.02) and did not change subsequently. Patients with grade I CAN had higher eGFR than those with grade II CAN. Patient and graft survival was 96% and 70% 10 yr after conversion. Patients with grade I CAN had better graft survival than those with grade II CAN: 89% vs. 65% at six yr (p = 0.02) post conversion. There were two episodes of BPAR. Baseline proteinuria >20 mg/kg/day (HR: 10) and baseline eGFR <50 mL/min/1.73 m(2) (HR: 8) were independent predictors of graft loss. Sixty-seven of 92 subjects had ≥1 AEs: diarrhea (n = 52), urinary tract infections (n = 35), and lower respiratory tract infections (n = 12) were the most frequent. Patients with >2 AEs had SRL blood levels >9 ng/mL at month 3 (p = 0.01). In conclusion, patients converted from CNI to SRL had good graft survival and tolerable but frequent AEs. Independent predictors of graft loss were baseline proteinuria and eGFR.
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Abstract
Imbalances between bone resorption and formation lie at the root of disorders such as osteoporosis, Paget's disease of bone (PDB), and osteopetrosis. Recently, genetic and functional studies have implicated proteins involved in autophagic protein degradation as important mediators of bone cell function in normal physiology and in pathology. Autophagy is the conserved process whereby aggregated proteins, intracellular pathogens, and damaged organelles are degraded and recycled. This process is important both for normal cellular quality control and in response to environmental or internal stressors, particularly in terminally-differentiated cells. Autophagic structures can also act as hubs for the spatial organization of recycling and synthetic process in secretory cells. Alterations to autophagy (reduction, hyperactivation, or impairment) are associated with a number of disorders, including neurodegenerative diseases and cancers, and are now being implicated in maintenance of skeletal homoeostasis. Here, we introduce the topic of autophagy, describe the new findings that are starting to emerge from the bone field, and consider the therapeutic potential of modifying this pathway for the treatment of age-related bone disorders.
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Affiliation(s)
- Lynne J Hocking
- Musculoskeletal Research Programme, Division of Applied Medicine, University of Aberdeen, Aberdeen, UK.
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Brito I, Gil-Peña H, Molinos I, Loredo V, Henriques-Coelho T, Caldas-Afonso A, Santos F. Growth cartilage expression of growth hormone/insulin-like growth factor I axis in spontaneous and growth hormone induced catch-up growth. Growth Horm IGF Res 2012; 22:129-133. [PMID: 22583947 DOI: 10.1016/j.ghir.2012.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 12/21/2011] [Accepted: 04/19/2012] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Catch-up growth following the cessation of a growth inhibiting cause occurs in humans and animals. Although its underlying regulatory mechanisms are not well understood, current hypothesis confer an increasing importance to local factors intrinsic to the long bones' growth plate (GP). AIM The present study was designed to analyze the growth-hormone (GH)-insulin-like growth factor I (IGF-I) axis in the epiphyseal cartilage of young rats exhibiting catch-up growth as well as to evaluate the effect of GH treatment on this process. MATERIAL AND METHODS Female Sprague-Dawley rats were randomly grouped: controls (group C), 50% diet restriction for 3 days+refeeding (group CR); 50% diet restriction for 3 days+refeeding & GH treatment (group CRGH). Analysis of GH receptor (GHR), IGF-I, IGF-I receptor (IGF-IR) and IGF binding protein 5 (IGFBP5) expressions by real-time PCR was performed in tibial growth plates extracted at the time of catch-up growth, identified by osseous front advance greater than that of C animals. RESULTS In the absence of GH treatment, catch-up growth was associated with increased IGF-I and IGFBP5 mRNA levels, without changes in GHR or IGF-IR. GH treatment maintained the overexpression of IGF-I mRNA and induced an important increase in IGF-IR expression. CONCLUSIONS Catch-up growth that happens after diet restriction might be related with a dual stimulating local effect of IGF-I in growth plate resulting from overexpression and increased bioavailability of IGF-I. GH treatment further enhanced expression of IGF-IR which likely resulted in a potentiation of local IGF-I actions. These findings point out to an important role of growth cartilage GH/IGF-I axis regulation in a rat model of catch-up growth.
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Affiliation(s)
- Iva Brito
- Pediatric Rheumatology Unit, Pediatric Department, Hospital São João, Porto, Portugal.
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Álvarez-García Ó, García-López E, Loredo V, Gil-Peña H, Mejía-Gaviria N, Rodríguez-Suárez J, Ordóñez FÁ, Santos F. Growth hormone improves growth retardation induced by rapamycin without blocking its antiproliferative and antiangiogenic effects on rat growth plate. PLoS One 2012; 7:e34788. [PMID: 22493717 PMCID: PMC3321024 DOI: 10.1371/journal.pone.0034788] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 03/08/2012] [Indexed: 02/05/2023] Open
Abstract
Rapamycin, an immunosuppressant agent used in renal transplantation with antitumoral properties, has been reported to impair longitudinal growth in young individuals. As growth hormone (GH) can be used to treat growth retardation in transplanted children, we aimed this study to find out the effect of GH therapy in a model of young rat with growth retardation induced by rapamycin administration. Three groups of 4-week-old rats treated with vehicle (C), daily injections of rapamycin alone (RAPA) or in combination with GH (RGH) at pharmacological doses for 1 week were compared. GH treatment caused a 20% increase in both growth velocity and body length in RGH animals when compared with RAPA group. GH treatment did not increase circulating levels of insulin-like growth factor I, a systemic mediator of GH actions. Instead, GH promoted the maturation and hypertrophy of growth plate chondrocytes, an effect likely related to AKT and ERK1/2 mediated inactivation of GSK3β, increase of glycogen deposits and stabilization of β-catenin. Interestingly, GH did not interfere with the antiproliferative and antiangiogenic activities of rapamycin in the growth plate and did not cause changes in chondrocyte autophagy markers. In summary, these findings indicate that GH administration improves longitudinal growth in rapamycin-treated rats by specifically acting on the process of growth plate chondrocyte hypertrophy but not by counteracting the effects of rapamycin on proliferation and angiogenesis.
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Affiliation(s)
- Óscar Álvarez-García
- Department of Pediatrics, University of Oviedo, Oviedo, Spain
- Laboratory of Growth and Cancer, Instituto Universitario de Oncología del Principado de Asturias, Oviedo, Asturias, Spain
| | - Enrique García-López
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Vanessa Loredo
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Helena Gil-Peña
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | | | - Julián Rodríguez-Suárez
- Department of Pediatrics, University of Oviedo, Oviedo, Spain
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Flor Á. Ordóñez
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Fernando Santos
- Department of Pediatrics, University of Oviedo, Oviedo, Spain
- Laboratory of Growth and Cancer, Instituto Universitario de Oncología del Principado de Asturias, Oviedo, Asturias, Spain
- Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
- * E-mail:
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Trenor CC. Sirolimus for refractory vascular anomalies. Pediatr Blood Cancer 2011; 57:904-5. [PMID: 21538825 DOI: 10.1002/pbc.23178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 04/04/2011] [Indexed: 11/11/2022]
Affiliation(s)
- Cameron C Trenor
- Division of Hematology/Oncology, Vascular Anomalies Center, Children's Hospital Boston and Dana-Farber Cancer Institute, 300 Longwood Avenue, Boston, Massachusetts 02115, USA.
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Abstract
SRL, an mTOR inhibitor that inhibits cell cycle progression, represents an important alternative to CNIs, which are still the cornerstones of pediatric solid organ tx. Because there are still limited data on SRL use among pediatric solid organ recipients, further studies are needed to verify the efficacy and safety of SRL. It has unique pharmacokinetic characteristics concerning dosing intervals and reduction of the dose in combination with other immunosuppressants. SRL also has antineoplastic, antiviral, and antiatherogenic advantages over other immunosuppressive agents. The adverse effects of SRL including thrombocytopenia, hyperlipidemia, proteinuria, impaired wound healing, mouth ulcers, edema, male hypogonadism, TMA, and interstitial pneumonitis must be considered carefully in pediatric population. This article reviews the most recent data on SRL application in the field of pediatric renal tx.
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Affiliation(s)
- Belde Kasap
- Division of Pediatric Nephrology, Department of Pediatrics, School of Medicine, Dokuz Eylül University, İzmir, Turkey.
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Potential Therapeutic Roles for Inhibition of the PI3K/Akt/mTOR Pathway in the Pathophysiology of Diabetic Retinopathy. J Ophthalmol 2011; 2011:589813. [PMID: 22132311 PMCID: PMC3205601 DOI: 10.1155/2011/589813] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 07/13/2011] [Indexed: 02/08/2023] Open
Abstract
Novel therapeutics such as inhibitors of PI3K/Akt/mTOR pathway presents a unique opportunity for the management of diabetic retinopathy (DR). Second generation mTOR inhibitors have the prospect to be efficacious in managing various stages of disease progression in DR. During early stages, the mTOR inhibitors suppress HIF-1α, VEGF, leakage, and breakdown of the blood-retinal barrier. These mTOR inhibitors impart a pronounced inhibitory effect on inflammation, an early component with diverse ramifications influencing the progression of DR. These inhibitors suppress IKK and NF-κB along with downstream inflammatory cytokines, chemokines, and adhesion molecules. In proliferative DR, mTOR inhibitors suppress several growth factors that play pivotal roles in the induction of pathological angiogenesis. Lead mTOR inhibitors in clinical trials for ocular indications present an attractive treatment option for chronic use in DR with favorable safety profile and sustained ocular pharmacokinetics following single dose. Thereby, reducing dosing frequency and risk associated with chronic drug administration.
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Santos F, Alvarez-García O, González D. Sirolimus and growth. Pediatr Transplant 2011; 15:546-7. [PMID: 21762331 DOI: 10.1111/j.1399-3046.2011.01552.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Growth of kidney-transplanted pediatric patients treated with sirolimus. Pediatr Nephrol 2011; 26:961-6. [PMID: 21380626 DOI: 10.1007/s00467-011-1811-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
Abstract
Experimental findings indicate that sirolimus (SRL) inhibits longitudinal growth by mechanisms potentially related to its inhibitory effects on both cell proliferation and expression of vascular endothelial growth factor (VEGF). The aim of this study was to investigate the growth pattern of kidney-transplanted children treated with SRL in a multicenter observational clinical study. Height, change in height SD (Δ height) and growth velocity of pediatric patients with renal transplant were calculated at 0, 6, 12, and 24 months after starting SRL. Controls of kidney-transplanted children not treated with SRL were matched by age, gender, renal function, and dose of corticosteroids. Sixty-eight children (34 SRL, 34 controls) were enrolled in the study. Nephrotoxicity was the most frequent indication to start therapy with SRL. SRL exerted an adverse effect on growth as demonstrated by significantly lower (p < 0.05) growth velocity (cm/year) and smaller change in height SD in the SRL group after 6 (4.08 vs. 6.56 and -0.05 vs. 0.14), 12 (4.44 vs. 6.11 and -0.03 vs. 0.28) and 24 (4.53 vs. 6.03 and -0.04 vs. 0.53) months of treatment. This study suggests that SRL therapy may interfere with growth of kidney-transplanted children. This undesirable effect needs to be taken into account when considering a switch to SRL and confirmed in further prospective trials including larger number of patients.
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Wesseling-Perry K, Bacchetta J. CKD-MBD after kidney transplantation. Pediatr Nephrol 2011; 26:2143-51. [PMID: 21394466 PMCID: PMC3203246 DOI: 10.1007/s00467-011-1829-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 02/11/2011] [Accepted: 02/12/2011] [Indexed: 01/01/2023]
Abstract
Successful kidney transplantation corrects many of the metabolic abnormalities associated with chronic kidney disease (CKD); however, skeletal and cardiovascular morbidity remain prevalent in pediatric kidney transplant recipients and current recommendations from the Kidney Disease Improving Global Outcomes (KDIGO) working group suggest that bone disease-including turnover, mineralization, volume, linear growth, and strength-as well as cardiovascular disease be evaluated in all patients with CKD. Although few studies have examined bone histology after renal transplantation, current data suggest that bone turnover and mineralization are altered in the majority of patients and that biochemical parameters are poor predictors of bone histology in this population. Dual energy X-ray absorptiometry (DXA) scanning, although widely performed, has significant limitations in the pediatric transplant population and values have not been shown to correlate with fracture risk; thus, DXA is not recommended as a tool for the assessment of bone density. Newer imaging techniques, including computed tomography (quantitative CT (QCT), peripheral QCT (pQCT), high resolution pQCT (HR-pQCT) and magnetic resonance imaging (MRI)), which provide volumetric assessments of bone density and are able to discriminate bone microarchitecture, show promise in the assessment of bone strength; however, future studies are needed to define the value of these techniques in the diagnosis and treatment of renal osteodystrophy in pediatric renal transplant recipients.
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Affiliation(s)
- Katherine Wesseling-Perry
- Department of Pediatrics, David Geffen School of Medicine at UCLA, A2-383 MDCC, 650 Charles Young Drive, Los Angeles, CA 90095, USA.
| | - Justine Bacchetta
- Department of Pediatrics, David Geffen School of Medicine at UCLA, A2-383 MDCC, 650 Charles Young Drive, Los Angeles, CA 90095 USA
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Bid HK, Houghton PJ. Targeting angiogenesis in childhood sarcomas. Sarcoma 2010; 2011:601514. [PMID: 21197468 PMCID: PMC3005857 DOI: 10.1155/2011/601514] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 10/29/2010] [Indexed: 12/19/2022] Open
Abstract
Angiogenesis and vasculogenesis constitute two processes in the formation of new blood vessels and are essential for progression of solid tumors. Consequently, targeting angiogenesis, and to a lesser extent vasculogenesis, has become a major focus in cancer drug development. Angiogenesis inhibitors are now being tested in pediatric populations whereas inhibitors of vasculogenesis are in an earlier stage of development. Despite the initial enthusiasm for targeting angiogenesis for treatment of cancer, clinical trials have shown only incremental increases in survival, and agents have been largely cytostatic rather than inducing tumor regressions. Consequently, the role of such therapeutic approaches in the context of curative intent for childhood sarcomas is less clear. Here we review the literature on blood vessel formation in sarcomas with a focus on pediatric sarcomas and developments in targeting angiogenesis for treatment of these rare cancers.
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Affiliation(s)
- Hemant K. Bid
- Center for Childhood Cancer, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
| | - Peter J. Houghton
- Center for Childhood Cancer, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
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Lisse TS, Liu T, Irmler M, Beckers J, Chen H, Adams JS, Hewison M. Gene targeting by the vitamin D response element binding protein reveals a role for vitamin D in osteoblast mTOR signaling. FASEB J 2010; 25:937-47. [PMID: 21123297 DOI: 10.1096/fj.10-172577] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transcriptional regulation by hormonal 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] involves occupancy of vitamin D response elements (VDREs) by the VDRE binding protein (VDRE-BP) or 1,25(OH)(2)D(3)-bound vitamin D receptor (VDR). This relationship is disrupted by elevated VDRE-BP, causing a form of hereditary vitamin D-resistant rickets (HVDRR). DNA array analysis showed that of 114 genes regulated by 1,25(OH)(2)D(3) in control cells, almost all (113) were rendered insensitive to the hormone in VDRE-BP-overexpressing HVDRR cells. Among these was the gene for DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling. Chromatin immunoprecipitation PCR using 1,25(OH)(2)D(3)-treated osteoblasts confirmed that VDR and VDRE-BP compete for binding to the DDIT4 gene promoter. Expression of DDIT4 mRNA in these cells was induced (1.6-6 fold) by 1,25(OH)(2)D(3) (10-100 nM), and Western blot and flow cytometry analysis showed that this response involved suppression of phosphorylated S6K1(T389) (a downstream target of mTOR) similar to rapamycin treatment. siRNA knockdown of DDIT4 completely abrogated antiproliferative responses to 1,25(OH)(2)D(3), whereas overexpression of VDRE-BP exerted a dominant-negative effect on transcription of 1,25(OH)(2)D(3)-target genes. DDIT4, an inhibitor of mTOR signaling, is a direct target for 1,25(OH)(2)D(3) and VDRE-BP, and functions to suppress cell proliferation in response to vitamin D.
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Affiliation(s)
- Thomas S Lisse
- Orthopaedic Hospital Research Center, University of California-Los Angeles, 615 Charles E. Young Dr., South Los Angeles, CA 90095, USA
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