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Guleray Lafci N, van Goor M, Cetinkaya S, van der Wijst J, Acun M, Kurt Colak F, Cetinkaya A, Hoenderop J. Decreased calcium permeability caused by biallelic TRPV5 mutation leads to autosomal recessive renal calcium-wasting hypercalciuria. Eur J Hum Genet 2024:10.1038/s41431-024-01589-9. [PMID: 38528055 DOI: 10.1038/s41431-024-01589-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/10/2024] [Accepted: 03/04/2024] [Indexed: 03/27/2024] Open
Abstract
Hypercalciuria is the most common metabolic risk factor in people with kidney stone disease. Its etiology is mostly multifactorial, although monogenetic causes of hypercalciuria have also been described. Despite the increased availability of genetic diagnostic tests, the vast majority of individuals with familial hypercalciuria remain unsolved. In this study, we investigated a consanguineous pedigree with idiopathic hypercalciuria. The proband additionally exhibited severe skeletal deformities and hyperparathyroidism. Whole-exome sequencing of the proband revealed a homozygous ultra-rare variant in TRPV5 (NM_019841.7:c.1792G>A; p.(Val598Met)), which encodes for a renal Ca2+-selective ion channel. The variant segregates with the three individuals with hypercalciuria. The skeletal phenotype unique to the proband was due to an additional pathogenic somatic mutation in GNAS (NM_000516.7:c.601C>T; p.(Arg201Cys)), which leads to polyostotic fibrous dysplasia. The variant in TRPV5 is located in the TRP helix, a characteristic amphipathic helix that is indispensable for the gating movements of TRP channels. Biochemical characterization of the TRPV5 p.(Val598Met) channel revealed a complete loss of Ca2+ transport capability. This defect is caused by reduced expression of the mutant channel, due to misfolding and preferential targeting to the proteasome for degradation. Based on these findings, we conclude that biallelic loss of TRPV5 function causes a novel form of monogenic autosomal recessive hypercalciuria, which we name renal Ca2+-wasting hypercalciuria (RCWH). The recessive inheritance pattern explains the rarity of RCWH and underscores the potential prevalence of RCWH in highly consanguineous populations, emphasizing the importance of exploration of this disorder within such communities.
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Affiliation(s)
- Naz Guleray Lafci
- Hacettepe University, Medical Faculty, Department of Medical Genetics, Ankara, Turkey
- Health Science University, Dr. Sami Ulus Obstetrics and Gynecology, Children Health and Disease Training and Research Hospital, Department of Medical Genetics, Ankara, Turkey
| | - Mark van Goor
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Semra Cetinkaya
- Health Science University, Dr. Sami Ulus Obstetrics and Gynecology, Children Health and Disease Training and Research Hospital, Department of Pediatric Endocrinology, Ankara, Turkey
| | - Jenny van der Wijst
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Melisa Acun
- Hacettepe University, Institute of Health Sciences, Department of Bioinformatics, Ankara, Turkey
| | - Fatma Kurt Colak
- Health Science University, Dr. Sami Ulus Obstetrics and Gynecology, Children Health and Disease Training and Research Hospital, Department of Medical Genetics, Ankara, Turkey
| | - Arda Cetinkaya
- Hacettepe University, Medical Faculty, Department of Medical Genetics, Ankara, Turkey.
- Hacettepe University, Institute of Health Sciences, Department of Bioinformatics, Ankara, Turkey.
| | - Joost Hoenderop
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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Verlinden L, Li S, Veldurthy V, Carmeliet G, Christakos S. Relationship of the bone phenotype of the Klotho mutant mouse model of accelerated aging to changes in skeletal architecture that occur with chronological aging. Front Endocrinol (Lausanne) 2024; 15:1310466. [PMID: 38352710 PMCID: PMC10861770 DOI: 10.3389/fendo.2024.1310466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024] Open
Abstract
Introduction Due to the relatively long life span of rodent models, in order to expediate the identification of novel therapeutics of age related diseases, mouse models of accelerated aging have been developed. In this study we examined skeletal changes in the male and female Klotho mutant (kl/kl) mice and in male and female chronically aged mice to determine whether the accelerated aging bone phenotype of the kl/kl mouse reflects changes in skeletal architecture that occur with chronological aging. Methods 2, 6 and 20-23 month old C57BL/6 mice were obtained from the National Institute of Aging aged rodent colony and wildtype and kl/kl mice were generated as previously described by M. Kuro-o. Microcomputed tomography analysis was performed ex vivo to examine trabecular and cortical parameters from the proximal metaphyseal and mid-diaphyseal areas, respectively. Serum calcium and phosphate were analyzed using a colorimetric assay. The expression of duodenal Trpv6, which codes for TRPV6, a vitamin D regulated epithelial calcium channel whose expression reflects intestinal calcium absorptive efficiency, was analyzed by quantitative real-time PCR. Results and discussion Trabecular bone volume (BV/TV) and trabecular number decreased continuously with age in males and females. In contrast to aging mice, an increase in trabecular bone volume and trabecular number was observed in both male and female kl/kl mice. Cortical thickness decreased with advancing age and also decreased in male and female kl/kl mice. Serum calcium and phosphate levels were significantly increased in kl/kl mice but did not change with age. Aging resulted in a decline in Trpv6 expression. In the kl/kl mice duodenal Trpv6 was significantly increased. Our findings reflect differences in bone architecture as well as differences in calcium and phosphate homeostasis and expression of Trpv6 between the kl/kl mutant mouse model of accelerated aging and chronological aging. Although the Klotho deficient mouse has provided a new understanding of the regulation of mineral homeostasis and bone metabolism, our findings suggest that changes in bone architecture in the kl/kl mouse reflect in part systemic disturbances that differ from pathophysiological changes that occur with age including dysregulation of calcium homeostasis that contributes to age related bone loss.
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Affiliation(s)
- Lieve Verlinden
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Shanshan Li
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ, United States
| | - Vaishali Veldurthy
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ, United States
| | - Geert Carmeliet
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Sylvia Christakos
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ, United States
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Amarnath SS, Kumar V, Barik S. Vitamin D and Calcium and Bioavailability of Calcium in Various Calcium Salts. Indian J Orthop 2023; 57:62-69. [PMID: 38107810 PMCID: PMC10721582 DOI: 10.1007/s43465-023-01056-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 11/12/2023] [Indexed: 12/19/2023]
Abstract
Introduction The active form of vitamin D, 1,25D3, plays an important function in the metabolism of calcium. The recommended daily INTAKE of Calcium varies from 1300 mg/day during adolescence to 1200 mg/day after the age of 50 years. Similarly, for vitamin D, the recommended daily intake varies from 400 IU/day during adolescence to 1000 IU/day after the age of 70 years. There is an intricate inter-play of homeostasis of calcium led by vitamin D and PTH at various sites like intestine, kidney, and bones. The increased fracture risk due to bone loss and osteoporosis creates a burden on the patient, healthcare provider as well as the health system. As the population grows old worldwide gradually, the long-term sequelae like pain, loss of independence, and institutionalized care will become more pervasive. Behavioral change to incorporate a healthy lifestyle, including optimal calcium and vitamin D intake and physical exercise in adolescence, form the important foundation in the program for osteoporosis prevention. Conclusion Increased emphasis on lifestyle modification and nutrition should be given during times of increased bone loss in old age and after menopause.
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Affiliation(s)
- S. S. Amarnath
- Trauma and Orthopedic Surgeon, Trinity Central Hospital, Bangalore, India
| | - Vishal Kumar
- Department of Orthopedics, PGIMER, Chandigarh, India
| | - Sitanshu Barik
- Department of Orthopedics, All India Institute of Medical Sciences, Deoghar, India
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Mahmudpour M, Homayoun N, Nabipour I, Kalantar Hormozi MR, Boushehri SN, Larijani B, Ostovar A, Amini A, Marzban M. Association of age-related declined renal function and osteoporosis based on trabecular bone score in Bushehr Elderly Health (BEH) program. BMC Nephrol 2023; 24:224. [PMID: 37507659 PMCID: PMC10375762 DOI: 10.1186/s12882-023-03280-5] [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: 10/29/2022] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
PURPOSE Osteoporosis is a systemic disease characterized by decreased bone strength and an increased risk of fracture in old age. Age and pathologic renal failure are independent risk factors for osteoporosis. However, it is not determined whether age-related decreased renal function, in the context of senescence, can be considered as an independent risk factor for osteoporosis. Therefore, this study was conducted to evaluate the effect of senescence-induced renal failure on bone quality and trabecular bone score. METHODS This study used a cross-sectional design and was carried out based on data collected during the Bushehr Elderly Health (BEH) program, Phase II. A total of 2,125 elderly participants aged over 60 years old entered the study after meeting the inclusion criteria and providing informed consent. They underwent examinations for weight, height, abdominal and hip circumference, as well as blood pressure measurement. All participants also underwent DXA to assess bone mass density (BMD). Trabecular bone score (TBS) was calculated using the DXA apparatus software output. Univariate and adjusted multivariate linear regression analyses were used to evaluate the associations. RESULTS In the univariate linear regression analysis, there was a direct correlation between age-related renal failure and TBS (β = 0.038, p < 0.0001), neck of femur BMD (β = 0.047, p < 0.0001), and lumbar BMD (β = 0.055, p < 0.0001). However, after adjusting for BMI, age, sex, smoking, and physical activity, no significant association was observed for these variables. CONCLUSION It is hypothesized that age-related renal failure cannot be considered as an independent risk factor for osteoporosis in elderly individuals aged over 60 years old.
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Affiliation(s)
- Mehdi Mahmudpour
- The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Narges Homayoun
- Student Research Committee, Bushehr University Of Medical Sciences, Bushehr, Iran
- Department of Internal Medicine, School of Medicine, Bushehr University Of Medical Sciences, Bushehr, Iran
| | - Iraj Nabipour
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | | | - Saeid Najafpour Boushehri
- Clinical Research Development Center, The Persian Gulf Martyrs, Bushehr University of Medical Science, Bushehr, 7514763448, Iran
| | - Bagher Larijani
- Osteoporosis Research Center. Endocrinology and Metabolism Clinical Sciences Institute. Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Afshin Ostovar
- Osteoporosis Research Center. Endocrinology and Metabolism Clinical Sciences Institute. Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Azam Amini
- Department of Internal Medicine, School of Medicine, Bushehr University Of Medical Sciences, Bushehr, Iran
| | - Maryam Marzban
- Clinical Research Development Center, The Persian Gulf Martyrs, Bushehr University of Medical Science, Bushehr, 7514763448, Iran.
- Statistical Genetics Lab, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
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Luo ZH, Ma JX, Zhang W, Tian AX, Gong SW, Li Y, Lai YX, Ma XL. Alterations in the microenvironment and the effects produced of TRPV5 in osteoporosis. J Transl Med 2023; 21:327. [PMID: 37198647 DOI: 10.1186/s12967-023-04182-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 05/05/2023] [Indexed: 05/19/2023] Open
Abstract
The pathogenesis of osteoporosis involves multiple factors, among which alterations in the bone microenvironment play a crucial role in disrupting normal bone metabolic balance. Transient receptor potential vanilloid 5 (TRPV5), a member of the TRPV family, is an essential determinant of the bone microenvironment, acting at multiple levels to influence its properties. TRPV5 exerts a pivotal influence on bone through the regulation of calcium reabsorption and transportation while also responding to steroid hormones and agonists. Although the metabolic consequences of osteoporosis, such as loss of bone calcium, reduced mineralization capacity, and active osteoclasts, have received significant attention, this review focuses on the changes in the osteoporotic microenvironment and the specific effects of TRPV5 at various levels.
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Affiliation(s)
- Zhi-Heng Luo
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Jian-Xiong Ma
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Wei Zhang
- Centre for Translational Medicine Research & Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xue Yuan Avenue, Shenzhen University Town, Shenzhen, 518055, Guangdong, People's Republic of China
| | - Ai-Xian Tian
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Shu-Wei Gong
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Yan Li
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Yu-Xiao Lai
- Centre for Translational Medicine Research & Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xue Yuan Avenue, Shenzhen University Town, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Xin-Long Ma
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China.
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China.
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Gharpure M, Chen J, Nerella R, Vyavahare S, Kumar S, Isales CM, Hamrick M, Adusumilli S, Fulzele S. Sex-specific alteration in human muscle transcriptome with age. GeroScience 2023:10.1007/s11357-023-00795-5. [PMID: 37106281 PMCID: PMC10400750 DOI: 10.1007/s11357-023-00795-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Sarcopenia is a medical condition that progressively develops with age and results in reduced skeletal muscle mass, alteration in muscle composition, and decreased muscle strength. Several clinical studies suggested that sarcopenia disproportionally affects males and females with age. Despite this knowledge, the molecular mechanism governing the pathophysiology is not well understood in a sex-specific manner. In this study, we utilized human gastrocnemius muscles from males and females to identify differentially regulated genes with age. We found 269 genes with at least a twofold expression difference in the aged muscle transcriptome. Among the female muscle samples, there were 239 differentially regulated genes, and the novel protein-coding genes include KIF20A, PIMREG, MTRNR2L6, TRPV6, EFNA2, RNF24, and SFN. In aged male skeletal muscle, there were 166 differentially regulated genes, and the novel-protein coding genes are CENPK, CDKN2A, BHLHA15, and EPHA. Gene Ontology (GO) enrichment revealed glucose catabolism, NAD metabolic processes, and muscle fiber transition pathways that are involved in aged female skeletal muscle, whereas replicative senescence, cytochrome C release, and muscle composition pathways are disrupted in aged male skeletal muscle. Targeting these novels, differentially regulated genes, and signaling pathways could serve as sex-specific therapeutic targets to combat the age-related onset of sarcopenia and promote healthy aging.
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Affiliation(s)
- Mohini Gharpure
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Jie Chen
- Division of Biostatistics and Data Science, Department of Population Health Sciences, Augusta University, Augusta, GA, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Resheek Nerella
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
- Augusta University, Augusta, GA, 30912, USA
| | - Sagar Vyavahare
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Sandeep Kumar
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
| | - Carlos M Isales
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Mark Hamrick
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | | | - Sadanand Fulzele
- Department of Medicine, Medical College of Georgia, Augusta University, GA, Augusta, USA.
- Center for Healthy Aging, Augusta University, Augusta, GA, USA.
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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Khattar V, Wang L, Peng JB. Calcium selective channel TRPV6: Structure, function, and implications in health and disease. Gene 2022; 817:146192. [PMID: 35031425 PMCID: PMC8950124 DOI: 10.1016/j.gene.2022.146192] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 12/14/2022]
Abstract
Calcium-selective channel TRPV6 (Transient Receptor Potential channel family, Vanilloid subfamily member 6) belongs to the TRP family of cation channels and plays critical roles in transcellular calcium (Ca2+) transport, reuptake of Ca2+ into cells, and maintaining a local low Ca2+ environment for certain biological processes. Recent crystal and cryo-electron microscopy-based structures of TRPV6 have revealed mechanistic insights on how the protein achieves Ca2+ selectivity, permeation, and inactivation by calmodulin. The TRPV6 protein is expressed in a range of epithelial tissues such as the intestine, kidney, placenta, epididymis, and exocrine glands such as the pancreas, prostate and salivary, sweat, and mammary glands. The TRPV6 gene is a direct transcriptional target of the active form of vitamin D and is efficiently regulated to meet the body's need for Ca2+ demand. In addition, TRPV6 is also regulated by the level of dietary Ca2+ and under physiological conditions such as pregnancy and lactation. Genetic models of loss of function in TRPV6 display hypercalciuria, decreased bone marrow density, deficient weight gain, reduced fertility, and in some cases alopecia. The models also reveal that the channel plays an indispensable role in maintaining maternal-fetal Ca2+ transport and low Ca2+ environment in the epididymal lumen that is critical for male fertility. Most recently, loss of function mutations in TRPV6 gene is linked to transient neonatal hyperparathyroidism and early onset chronic pancreatitis. TRPV6 is overexpressed in a wide range of human malignancies and its upregulation is strongly correlated to tumor aggressiveness, metastasis, and poor survival in selected cancers. This review summarizes the current state of knowledge on the expression, structure, biophysical properties, function, polymorphisms, and regulation of TRPV6. The aberrant expression, polymorphisms, and dysfunction of this protein linked to human diseases are also discussed.
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Affiliation(s)
- Vinayak Khattar
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Irsik DL, Bollag WB, Isales CM. Renal Contributions to Age-Related Changes in Mineral Metabolism. JBMR Plus 2021; 5:e10517. [PMID: 34693188 PMCID: PMC8520061 DOI: 10.1002/jbm4.10517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/28/2021] [Accepted: 05/09/2021] [Indexed: 11/10/2022] Open
Abstract
Aging results in a general decline in function in most systems. This is particularly true with respect to the skeleton and renal systems, impacting mineral homeostasis. Calcium and phosphate regulation requires tight coordination among the intestine, bone, parathyroid gland, and kidney. The role of the intestine is to absorb calcium and phosphate from the diet. The bone stores or releases calcium and phosphate depending on the body's needs. In response to low plasma ionized calcium concentration, the parathyroid gland produces parathyroid hormone, which modulates bone turnover. The kidney reabsorbs or excretes the minerals and serves as the final regulator of plasma concentration. Many hormones are involved in this process in addition to parathyroid hormone, including fibroblast growth factor 23 produced by the bone and calcitriol synthesized by the kidney. Sclerostin, calcitonin, osteoprotegerin, and receptor activator of nuclear factor‐κB ligand also contribute to tissue‐specific regulation. Changes in the function of organs due to aging or disease can perturb this balance. During aging, the intestine cannot absorb calcium efficiently due to decreased expression of key proteins. In the bone, the balance between bone formation and bone resorption tends toward the latter in older individuals. The kidney may not filter blood as efficiently in the later decades of life, and the expression of certain proteins necessary for mineral homeostasis declines with age. These changes often lead to dysregulation of organismal mineral homeostasis. This review will focus on how mineral homeostasis is impacted by aging with a particular emphasis on the kidney's role in this process. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Debra L Irsik
- Charlie Norwood VA Medical Center Augusta GA USA.,Department of Neuroscience and Regenerative Medicine Augusta University Augusta GA USA
| | - Wendy B Bollag
- Charlie Norwood VA Medical Center Augusta GA USA.,Department of Physiology Augusta University Augusta GA USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine Augusta University Augusta GA USA.,Division of Endocrinology, Department of Medicine Augusta University Augusta GA USA
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Abstract
As the world's population ages, the treatment of osteoporosis is a major problem to be addressed. The cause of osteoporosis remains unclear. Ca2+ is not only an important component of bones but also plays a key role in osteoporosis treatment. Transient receptor potential vanilloid (TRPV) channels are one of the TRP channel families that is widely distributed in various organs, playing an important role in the physiological regulation of the human body. Bone formation and bone absorption may require Ca2+ transport via TRPV channels. It has been proven that the TRPV subtypes 1, 2, 4, 5, 6 (TRPV1, TRPV2, TRPV4, TRPV5, TRPV6) may affect bone metabolism balance through selective regulation of Ca2+. They significantly regulate osteoblast/osteoclast proliferation, differentiation and function. The purpose of this review is to explore the mechanisms of TRPV channels involved in regulation of the differentiation of osteoblasts and osteoclasts, as well as to discuss the latest developments in current researches, which may provide new clues and directions for an in-depth study of osteoporosis and other related bone metabolic diseases.
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Živanović J, Jarić I, Ajdžanović V, Miler M, Stanković S, Milošević V, Filipović B. Genistein regulates calcium and phosphate homeostasis without activation of MEK 1/2 signalling pathway in an animal model of the andropause. Ann Anat 2021; 239:151836. [PMID: 34563672 DOI: 10.1016/j.aanat.2021.151836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 01/02/2023]
Abstract
Soy isoflavone genistein interplays with numerous physiological or pathophysiological processes during ageing. However, its protective role and underlying mechanisms of action in the regulation of calcium (Ca2+) and phosphate (Pi) homeostasis in an animal model of the andropause are yet to be fully clarified. Wistar male rats (16-month-old) were divided into sham-operated, orchidectomized, orchidectomized estradiol-treated (0.625 mg/kg b.m./day) and orchidectomized genistein-treated (30 mg/kg b.m./day) groups. Treatments were administered subcutaneously for 3 weeks, while the controls received vehicle alone. Estradiol treatment increased the expression level of fibroblast growth factor receptor (FGFR) and parathyroid hormone 1 receptor (PTH1R), and activated mitogen - activated protein kinase kinase 1/2 (MEK 1/2) signaling pathway in the kidneys. Genistein application induced a prominent gene and protein expression of Klotho and downregulated the expression of FGFR and PTH1R in the kidney of andropausal rats. Activation of protein kinase B (Akt) signalling pathway was observed, while MEK 1/2 signaling pathway wasn't altered after genistein treatment. The increase of 25 (OH) vitamin D in the serum and decrease in Ca2+ urine content was observed after genistein application. Our findings strongly suggest genistein as a potent biocompound with beneficial effects on the regulation of Ca2+ and Pi homeostasis, especially during aging process when the balance of mineral metabolism is impaired. These novel data provide closer insights into the physiological roles of genistein in the regulation of mineral homeostasis.
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Affiliation(s)
- Jasmina Živanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia.
| | - Ivana Jarić
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia; Animal Welfare Division, Vetsuisse, University of Bern, Bern, Switzerland
| | - Vladimir Ajdžanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Marko Miler
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Sanja Stanković
- Center for Medical Biochemistry, Clinical Centre of Serbia, Belgrade, Serbia
| | - Verica Milošević
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Branko Filipović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Sato M, Morishita T, Katayama T, Satomura S, Okuno H, Sumida N, Sakuma M, Arai H, Katoh S, Sairyo K, Kawaura A, Takeda E. Relationship between age-related decreases in serum 25-hydroxyvitamin D levels and skeletal muscle mass in Japanese women. THE JOURNAL OF MEDICAL INVESTIGATION 2021; 67:151-157. [PMID: 32378599 DOI: 10.2152/jmi.67.151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
A clearer understanding of skeletal muscle mass (SMM) in middle-aged and elderly individuals is important for maintaining functionality. In the present study, age-related changes in SMM, the threshold of SMM with walking difficulty, intestinal nutrient absorption rate, and various serum factors were examined in Japanese populations of different ages. We used 24-h creatinine excretion as a measure of total body SMM. Age-related decreases in SMM, intestinal nutrient absorption rates, and serum 25-hydroxyvitamin D [25(OH)D] concentrations were significantly higher in women than in men. The cut-off values for SMM (kg), its percentage of total body weight (BW), the SMM index [SMMI] (Kg / m2), and creatinine height index (CHI) (%) in elderly individuals with walking difficulty were approximately 8-10 kg, 17-20% of BW, 3.9-4.6 kg / m2, and 44%, respectively. Serum 25(OH)D concentrations were closely associated with SMM (kg, % of BW, kg / m2) and CHI (%) as well as the intestinal absorption rates of nitrogen (%) and phosphorus (%) in women, but not in men. The present results demonstrate that vitamin D is an important metabolic factor in skeletal muscle, and contributes to the optimal management of skeletal muscle and the prevention of sarcopenia. J. Med. Invest. 67 : 151-157, February, 2020.
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Affiliation(s)
- Michiko Sato
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan.,Equally contributed to this study
| | - Teruhiro Morishita
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan.,Equally contributed to this study
| | - Takafumi Katayama
- Department of Statistics and Computer Science, College of Nursing Art and Science, University of Hyogo, Akashi, Japan
| | - Shigeko Satomura
- Division of Child Neurology, Tokushima Prefectural Hinomine Medical Center for the Handicapped, Komatsushima, Japan
| | - Hiroko Okuno
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan
| | - Nami Sumida
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan
| | - Masae Sakuma
- Department of Human Nutrition, School of Life Studies, Sugiyama Jogakuen University, Nagoya, Japan
| | - Hidekazu Arai
- Laboratory of Clinical Nutrition and Management, Graduate School of Nutritional and Environmental Sciences, The University of Shizuoka, Shizuoka, Japan
| | - Shinsuke Katoh
- Department of Rehabilitation Medicine, Tokushima University Hospital, Tokushima, Japan
| | - Koichi Sairyo
- Department of Orthopedics, Tokushima University, Tokushima, Japan
| | - Akihiko Kawaura
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan
| | - Eiji Takeda
- Kenshokai Gakuen College for Health and Welfare, Tokushima, Japan
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12
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Cannarella R, Barbagallo F, Condorelli RA, Aversa A, La Vignera S, Calogero AE. Osteoporosis from an Endocrine Perspective: The Role of Hormonal Changes in the Elderly. J Clin Med 2019; 8:jcm8101564. [PMID: 31581477 PMCID: PMC6832998 DOI: 10.3390/jcm8101564] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/09/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023] Open
Abstract
Introduction: Osteoporosis is increasingly prevalent in the elderly, with fractures mostly occurring in women and men who are older than 55 and 65 years of age, respectively. The aim of this review was to examine the evidence regarding the influence of hormones on bone metabolism, followed by clinical data of hormonal changes in the elderly, in the attempt to provide possible poorly explored diagnostic and therapeutic candidate targets for the management of primary osteoporosis in the aging population. Material and methods: An extensive Medline search using PubMed, Embase, and Cochrane Library was performed. Results: While the rise in Thyroid-stimulating hormone (TSH) levels has a protective role on bone mass, the decline of estrogen, testosterone, Insulin-like growth factor 1 (IGF1), and vitamin D and the rise of cortisol, parathyroid hormone, and follicle-stimulating hormone (FSH) favor bone loss in the elderly. Particularly, the AA rs6166 FSH receptor (FSHR) genotype, encoding for a more sensitive FSHR than that encoded by the GG one, is associated with low total body mass density (BMD), independently of circulating estrogen. A polyclonal antibody with a FSHR-binding sequence against the β-subunit of murine FSH seems to be effective in ameliorating bone loss in ovariectomized mice. Conclusions: A complete hormonal assessment should be completed for both women and men during bone loss evaluation. Novel possible diagnostic and therapeutic tools might be developed for the management of male and female osteoporosis.
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Affiliation(s)
- Rossella Cannarella
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy.
| | - Federica Barbagallo
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy.
| | - Rosita A Condorelli
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy.
| | - Antonio Aversa
- Department of Experimental and Clinical Medicine, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy.
| | - Sandro La Vignera
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy.
| | - Aldo E Calogero
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy.
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13
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Živanović J, Jarić I, Ajdžanović V, Mojić M, Miler M, Šošić-Jurjević B, Milošević V, Filipović B. Daidzein upregulates anti-aging protein Klotho and NaPi 2a cotransporter in a rat model of the andropause. Ann Anat 2018; 221:27-37. [PMID: 30240906 DOI: 10.1016/j.aanat.2018.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/21/2018] [Accepted: 08/30/2018] [Indexed: 11/25/2022]
Abstract
In a rat model of the andropause we aimed to examine the influence of daidzein, soy isoflavone, on the structure and function of parathyroid glands (PTG) and the expression levels of some of the crucial regulators of Ca2+ and Pi homeostasis in the kidney, and to compare these effects with the effects of estradiol, serving as a positive control. Middle-aged (16-month-old) male Wistar rats were divided into the following groups: sham-operated (SO), orchidectomized (Orx), orchidectomized and estradiol-treated (Orx+E; 0.625mg/kg b.w./day, s.c.) as well as orchidectomized and daidzein-treated (Orx+D; 30mg/kg b.w./day, s.c.) group. Every treated group had a corresponding control group. PTH serum concentration was decreased in Orx+E and Orx+D groups by 10% and 21% (p<0.05) respectively, in comparison with the Orx. PTG volume was decreased in Orx+E group by 16% (p<0.05), when compared to the Orx. In Orx+E group expression of NaPi 2a was lower (p<0.05), while NaPi 2a abundance in Orx+D animals was increased (p<0.05), when compared to Orx. Expression of PTH1R was increased (p<0.05) in Orx+E group, while in Orx+D animals the same parameter was decreased (p<0.05), in comparison with Orx. Klotho expression was elevated (p<0.05) in Orx+D rats, in regard to Orx. Orx+D induced reduction in Ca2+/creatinine and Pi/creatinine ratio in urine by 32% and 16% (p<0.05) respectively, in comparison with Orx. In conclusion, presented results indicate the more coherent beneficial effects of daidzein compared to estradiol, on disturbed Ca2+ and Pi homeostasis, and presumably on bone health, in the aging male rats.
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Affiliation(s)
- Jasmina Živanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
| | - Ivana Jarić
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Vladimir Ajdžanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Marija Mojić
- Department of Immunology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Marko Miler
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Branka Šošić-Jurjević
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Verica Milošević
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Branko Filipović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
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14
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Khalil R, Kim NR, Jardi F, Vanderschueren D, Claessens F, Decallonne B. Sex steroids and the kidney: role in renal calcium and phosphate handling. Mol Cell Endocrinol 2018; 465:61-72. [PMID: 29155307 DOI: 10.1016/j.mce.2017.11.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 12/16/2022]
Abstract
Calcium and phosphate are vital for the organism and constitute essential components of the skeleton. Serum levels are tightly hormonally regulated and maintained by exchange with three major sources: the intestines, the kidney and the bone. The effects of sex steroids on the bone have been extensively studied and it is well known that sex steroid deficiency induces bone loss, indirectly influencing renal calcium and phosphate homeostasis. However, it is unknown whether sex steroids also directly regulate renal calcium and phosphate handling, hereby potentially indirectly impacting on bone. The presence of androgen receptors (AR) and estrogen receptors (ER) in both human and rodent kidney, although their exact localization within the kidney remains debated, supports direct effects. Estrogens stimulate renal calcium reabsorption as well as phosphate excretion, while the effects of androgens are less clear. Many of the studies performed with regard to renal calcium and/or phosphate homeostasis do not correct for the calcium and phosphate fluxes from the bone and intestines, which complicates the differentiation between the direct effects of sex steroids on renal calcium and phosphate handling and the indirect effects via the bone and intestines. The objective of this study is to review the literature and current insight of the role of sex steroids in calcium and phosphate handling in the kidney.
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Affiliation(s)
- Rougin Khalil
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 Box 902, Belgium.
| | - Na Ri Kim
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 Box 902, Belgium
| | - Ferran Jardi
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 Box 902, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 Box 902, Belgium
| | - Frank Claessens
- Molecular Endocrinology, KU Leuven, Herestraat 49 Box 901, Belgium
| | - Brigitte Decallonne
- Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49 Box 902, Belgium
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15
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de Jongh RT, van Schoor NM, Lips P. Changes in vitamin D endocrinology during aging in adults. Mol Cell Endocrinol 2017; 453:144-150. [PMID: 28602863 DOI: 10.1016/j.mce.2017.06.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/04/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022]
Abstract
Worldwide, vitamin D deficiency is a common finding. Within individuals 25-hydroxyvitamin D (25OH)D) concentrations remain fairly stable over time although large differences in individual longitudinal changes exist. During aging vitamin D metabolism and activity changes in several different ways. Intestinal resistance to 1,25(OH)2D develops which hampers intestinal calcium uptake. Vitamin D receptor number decreases with aging in several organs involved in calcium metabolism and 1alpha-hydroxylase activity decreases mainly due to a decrease in renal function reducing vitamin D activation. Effects of 1,25(OH)2D on cell proliferation and differentiation may influence potential anti-cancer effects whereas regulation of telomere length may result in longevity. In older individuals, vitamin D supplementation has positive effects on fracture risk, number of falls and physical function. Supplementation in older populations warrants specific attention. Effects on "non-classical" outcomes may be revealed by ongoing large randomized clinical trials with high doses of vitamin D.
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Affiliation(s)
- Renate T de Jongh
- Department of Internal Medicine and Endocrinology, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
| | - Natasja M van Schoor
- Amsterdam Public Health Research Institute, Department of Epidemiology and Biostatistics, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
| | - Paul Lips
- Department of Internal Medicine and Endocrinology, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands; Amsterdam Public Health Research Institute, Department of Epidemiology and Biostatistics, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
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16
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Soni H, Peixoto-Neves D, Matthews AT, Adebiyi A. TRPV4 channels contribute to renal myogenic autoregulation in neonatal pigs. Am J Physiol Renal Physiol 2017; 313:F1136-F1148. [PMID: 28768667 DOI: 10.1152/ajprenal.00300.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/20/2017] [Accepted: 07/26/2017] [Indexed: 12/20/2022] Open
Abstract
Myogenic response, a phenomenon in which resistance size arteries and arterioles swiftly constrict or dilate in response to an acute elevation or reduction, respectively, in intravascular pressure is a key component of renal autoregulation mechanisms. Although it is well established that the renal system is functionally immature in neonates, mechanisms that regulate neonatal renal blood flow (RBF) remain poorly understood. In this study, we investigated the hypothesis that members of the transient receptor potential vanilloid (TRPV) channels are molecular components of renal myogenic constriction in newborns. We show that unlike TRPV1-3, TRPV4 channels are predominantly expressed in neonatal pig preglomerular vascular smooth muscle cells (SMCs). Intracellular Ca2+ concentration ([Ca2+]i) elevation induced by osmotic cell swelling was attenuated by TRPV4, L-type Ca2+, and stretch-activated Ca2+ channel blockers but not phospholipase A2 inhibitor. Blockade of TRPV4 channels reversed steady-state myogenic tone and inhibited pressure-induced membrane depolarization, [Ca2+]i elevation, and constriction in distal interlobular arteries. A step increase in arterial pressure induced efficient autoregulation of renal cortical perfusion and total RBF in anesthetized and mechanically ventilated neonatal pigs. Moreover, intrarenal arterial infusion of the TRPV4 channel blockers HC 067047 and RN 1734 attenuated renal autoregulation in the pigs. These data suggest that renal myogenic autoregulation is functional in neonates. Our findings also indicate that TRPV4 channels are mechanosensors in neonatal pig preglomerular vascular SMCs and contribute to renal myogenic autoregulation.
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Affiliation(s)
- Hitesh Soni
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Dieniffer Peixoto-Neves
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Anberitha T Matthews
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Adebowale Adebiyi
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
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17
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Beggs MR, Alexander RT. Intestinal absorption and renal reabsorption of calcium throughout postnatal development. Exp Biol Med (Maywood) 2017; 242:840-849. [PMID: 28346014 DOI: 10.1177/1535370217699536] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Calcium is vital for many physiological functions including bone mineralization. Postnatal deposition of calcium into bone is greatest in infancy and continues through childhood and adolescence until peek mineral density is reached in early adulthood. Thereafter, bone mineral density remains static until it eventually declines in later life. A positive calcium balance, i.e. more calcium absorbed than excreted, is crucial to bone deposition during growth and thus to peek bone mineral density. Dietary calcium is absorbed from the intestine into the blood. It is then filtered by the renal glomerulus and either reabsorbed by the tubule or excreted in the urine. Calcium can be (re)absorbed across intestinal and renal epithelia via both transcellular and paracellular pathways. Current evidence suggests that significant intestinal and renal calcium transport changes occur throughout development. However, the molecular details of these alterations are incompletely delineated. Here we first briefly review the current model of calcium transport in the intestine and renal tubule in the adult. Then, we describe what is known with regard to calcium handling through postnatal development, and how alterations may aid in mediating a positive calcium balance. The role of transcellular and paracellular calcium transport pathways and the contribution of specific intestinal and tubular segments vary with age. However, the current literature highlights knowledge gaps in how specifically intestinal and renal calcium (re)absorption occurs early in postnatal development. Future research should clarify the specific changes in calcium transport throughout early postnatal development including mediators of these alterations enabling appropriate bone mineralization. Impact statement This mini review outlines the current state of knowledge pertaining to the molecules and mechanisms maintaining a positive calcium balance throughout postnatal development. This process is essential to achieving optimal bone mineral density in early adulthood, thereby lowering the lifetime risk of osteoporosis.
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Affiliation(s)
- Megan R Beggs
- 1 Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2R7, Canada
| | - R Todd Alexander
- 1 Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2R7, Canada.,2 Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2R7, Canada
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18
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Christakos S, Veldurthy V, Patel N, Wei R. Intestinal Regulation of Calcium: Vitamin D and Bone Physiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1033:3-12. [PMID: 29101648 DOI: 10.1007/978-3-319-66653-2_1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The principal function of vitamin D in the maintenance of calcium homeostasis is to increase intestinal calcium absorption. This conclusion was made from studies in vitamin D receptor (VDR) null mice which showed that rickets and osteomalacia were prevented when VDR null mice were fed a rescue diet that included high calcium, indicating that the skeletal abnormalities of the VDR null mice are primarily the result of impaired intestinal calcium absorption. Although vitamin D is critical for controlling intestinal calcium absorption, the mechanisms involved have remained incomplete. This chapter reviews studies, including studies in genetically modified mice, that have provided new insight and have challenged the traditional model of VDR-mediated calcium absorption.
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Affiliation(s)
- Sylvia Christakos
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers the State University of New Jersey, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, 07103, USA.
| | - Vaishali Veldurthy
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers the State University of New Jersey, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Nishant Patel
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers the State University of New Jersey, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Ran Wei
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers the State University of New Jersey, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, 07103, USA
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19
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Verdelli C, Corbetta S. MECHANISMS IN ENDOCRINOLOGY: Kidney involvement in patients with primary hyperparathyroidism: an update on clinical and molecular aspects. Eur J Endocrinol 2017; 176:R39-R52. [PMID: 27601015 DOI: 10.1530/eje-16-0430] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/12/2016] [Accepted: 09/02/2016] [Indexed: 12/27/2022]
Abstract
Primary hyperparathyroidism (PHPT) is the third most common endocrine disease. Kidney is a target of both chronic elevated PTH and calcium in PHPT. The classic PHPT complications of symptomatic kidney stones and nephrocalcinosis have become rare and the PHPT current presentation is asymptomatic with uncertain and long-lasting progression. Nonetheless, the routine use of imaging and of biochemical determinations have revealed the frequent occurrence of asymptomatic kidney stones, hypercalciuria and reduced kidney function in asymptomatic PHPT patients. Though the pathogenesis is far from being elucidated, PHPT is associated with reduced renal function, in terms of estimated glomerular filtration rate, and related increased morbidity and mortality. In the last decade, the effort of the Kidney Disease: Improving Global Outcomes (KDIGO) panel of experts highlighted that even mild reduction of kidney function is associated with increased risk of cardiovascular disease. These considerations provided the basis for the Fourth Workshop recommendations of a more extensive diagnostic workout about kidney features and of wider criteria for parathyroid surgery including asymptomatic kidney disease. Moreover, kidney involvement in PHPT is likely to be affected by variants of genes coding the key molecules regulating the calcium and ions renal handling; these features might have clinical relevance and should be considered both during diagnostic workout and follow-up. Finally, the effects of parathyroid surgery and of medical treatment on kidney involvement of PHPT are reviewed.
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Affiliation(s)
- C Verdelli
- Laboratory of Experimental EndocrinologyIRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - S Corbetta
- Laboratory of Experimental EndocrinologyIRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Endocrinology ServiceDepartment of Biomedical Sciences for Health, University of Milan, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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20
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Vitamin D, calcium homeostasis and aging. Bone Res 2016; 4:16041. [PMID: 27790378 PMCID: PMC5068478 DOI: 10.1038/boneres.2016.41] [Citation(s) in RCA: 198] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/31/2016] [Accepted: 09/04/2016] [Indexed: 12/15/2022] Open
Abstract
Osteoporosis is characterized by low bone mass and microarchitecture deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk. Evidence is accumulating for an important role of calcium deficiency as the process of aging is associated with disturbed calcium balance. Vitamin D is the principal factor that maintains calcium homeostasis. Increasing evidence indicates that the reason for disturbed calcium balance with age is inadequate vitamin D levels in the elderly. In this article, an overview of our current understanding of vitamin D, its metabolism, and mechanisms involved in vitamin D-mediated maintenance of calcium homeostasis is presented. In addition, mechanisms involved in age-related dysregulation of 1,25(OH)2D3 action, recommended daily doses of vitamin D and calcium, and the use of vitamin D analogs for the treatment of osteoporosis (which remains controversial) are reviewed. Elucidation of the molecular pathways of vitamin D action and modifications that occur with aging will be an active area of future research that has the potential to reveal new therapeutic strategies to maintain calcium balance.
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21
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van der Eerden BCJ, Koek WNH, Roschger P, Zillikens MC, Waarsing JH, van der Kemp A, Schreuders-Koedam M, Fratzl-Zelman N, Leenen PJM, Hoenderop JGJ, Klaushofer K, Bindels RJM, van Leeuwen JPTM. Lifelong challenge of calcium homeostasis in male mice lacking TRPV5 leads to changes in bone and calcium metabolism. Oncotarget 2016; 7:24928-41. [PMID: 27102152 PMCID: PMC5041880 DOI: 10.18632/oncotarget.8779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/31/2016] [Indexed: 11/25/2022] Open
Abstract
Trpv5 plays an important role in calcium (Ca2+) homeostasis, among others by mediating renal calcium reabsorption. Accordingly, Trpv5 deficiency strongly stresses Ca2+ homeostasis in order to maintain stable serum Ca2+. We addressed the impact of lifelong challenge of calcium homeostasis on the bone phenotype of these mice. Aging significantly increased serum 1,25(OH)2D3 and PTH levels in both genotypes but they were more elevated in Trpv5−/− mice, whereas serum Ca2+ was not affected by age or genotype. Age-related changes in trabecular and cortical bone mass were accelerated in Trpv5−/− mice, including reduced trabecular and cortical bone thickness as well as reduced bone mineralization. No effect of Trpv5 deficiency on bone strength was observed. In 78-week-old mice no differences were observed between the genotypes regarding urinary deoxypyridinoline, osteoclast number, differentiation and activity as well as osteoclast precursor numbers, as assessed by flow cytometry. In conclusion, life-long challenge of Ca2+ homeostasis present in Trpv5−/− mice causes accelerated bone aging and a low cortical and trabecular bone mass phenotype. The phenotype of the Trpv5−/− mice suggests that maintenance of adequate circulatory Ca2+ levels in patients with disturbances in Ca2+ homeostasis should be a priority in order to prevent bone loss at older age.
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Affiliation(s)
| | - W Nadia H Koek
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Paul Roschger
- Ludwig Boltzman Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | | | - Jan H Waarsing
- Department of Orthopedics, Erasmus MC, Rotterdam, The Netherlands
| | - Annemiete van der Kemp
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands
| | | | - Nadja Fratzl-Zelman
- Ludwig Boltzman Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | | | - Joost G J Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands
| | - Klaus Klaushofer
- Ludwig Boltzman Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - René J M Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, The Netherlands
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22
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Veldurthy V, Wei R, Campbell M, Lupicki K, Dhawan P, Christakos S. 25-Hydroxyvitamin D₃ 24-Hydroxylase: A Key Regulator of 1,25(OH)₂D₃ Catabolism and Calcium Homeostasis. VITAMINS AND HORMONES 2016; 100:137-50. [PMID: 26827951 DOI: 10.1016/bs.vh.2015.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
One of the most pronounced effects of the hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is increased synthesis of 25-hydroxyvitamin D3 24-hydroxylase (CYP24A1), the enzyme responsible for the catabolism of 1,25(OH)2D3. Thus, 1,25(OH)2D3 regulates its own metabolism, protecting against hypercalcemia and limiting the levels of 1,25(OH)2D3 in cells. This chapter summarizes the catalytic properties of CYP24A1, the recent data related to the crystal structure of CYP24A1, the findings obtained from the generation of mice deficient for the Cyp24a1 gene as well as recent data identifying a causal role of a genetic defect in CYP24A1 in certain patients with idiopathic infantile hypercalcemia. This chapter also reviews the regulation of renal and placental CYP24A1 as well as the genomic mechanisms, including coactivators, repressors, and epigenetic modification, involved in modulating 1,25(OH)2D3 regulation of CYP24A1. We conclude with future research directions related to this key regulator of 1,25(OH)2D3 catabolism and calcium homeostasis.
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Affiliation(s)
- Vaishali Veldurthy
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Ran Wei
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Megan Campbell
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Kamil Lupicki
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Puneet Dhawan
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Sylvia Christakos
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.
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Rémond D, Shahar DR, Gille D, Pinto P, Kachal J, Peyron MA, Dos Santos CN, Walther B, Bordoni A, Dupont D, Tomás-Cobos L, Vergères G. Understanding the gastrointestinal tract of the elderly to develop dietary solutions that prevent malnutrition. Oncotarget 2015; 6:13858-98. [PMID: 26091351 PMCID: PMC4546438 DOI: 10.18632/oncotarget.4030] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 05/13/2015] [Indexed: 12/11/2022] Open
Abstract
Although the prevalence of malnutrition in the old age is increasing worldwide a synthetic understanding of the impact of aging on the intake, digestion, and absorption of nutrients is still lacking. This review article aims at filling the gap in knowledge between the functional decline of the aging gastrointestinal tract (GIT) and the consequences of malnutrition on the health status of elderly. Changes in the aging GIT include the mechanical disintegration of food, gastrointestinal motor function, food transit, chemical food digestion, and functionality of the intestinal wall. These alterations progressively decrease the ability of the GIT to provide the aging organism with adequate levels of nutrients, what contributes to the development of malnutrition. Malnutrition, in turn, increases the risks for the development of a range of pathologies associated with most organ systems, in particular the nervous-, muscoskeletal-, cardiovascular-, immune-, and skin systems. In addition to psychological, economics, and societal factors, dietary solutions preventing malnutrition should thus propose dietary guidelines and food products that integrate knowledge on the functionality of the aging GIT and the nutritional status of the elderly. Achieving this goal will request the identification, validation, and correlative analysis of biomarkers of food intake, nutrient bioavailability, and malnutrition.
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Affiliation(s)
- Didier Rémond
- UMR 1019, UNH, CRNH Auvergne, INRA, 63000 Clermont-Ferrand, France
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, 63000 Clermont-Ferrand, France
| | - Danit R. Shahar
- Department of Public Health, The S. Daniel Abraham International Center for Health and Nutrition, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
| | - Doreen Gille
- Institute for Food Sciences IFS, Agroscope, Federal Department of Economic Affairs, Education and Research EAER, 3003 Berne, Switzerland
| | - Paula Pinto
- Escola Superior Agrária, Insituto Politécnico de Santarém, 2001-904 Santarem, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | | | - Marie-Agnès Peyron
- UMR 1019, UNH, CRNH Auvergne, INRA, 63000 Clermont-Ferrand, France
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, 63000 Clermont-Ferrand, France
| | - Claudia Nunes Dos Santos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, 2780-157 Oeiras, Portugal
| | - Barbara Walther
- Institute for Food Sciences IFS, Agroscope, Federal Department of Economic Affairs, Education and Research EAER, 3003 Berne, Switzerland
| | - Alessandra Bordoni
- Department of Agri-Food Sciences and Technologies, University of Bologna, 47521 Cesena, Italy
| | - Didier Dupont
- UMR 1253, Science et Technologie du Lait & de l'Œuf, INRA, 35000 Rennes, France
| | | | - Guy Vergères
- Institute for Food Sciences IFS, Agroscope, Federal Department of Economic Affairs, Education and Research EAER, 3003 Berne, Switzerland
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24
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Yang B, Duan X, Wu W, Ji W, Wu W, Zhong W, Zhao Z, Li S, Liu Y, Zeng G. Induction of TRPV5 expression by small activating RNA targeting gene promoter as a novel approach to regulate cellular calcium transportation. Life Sci 2014; 114:70-6. [PMID: 25139832 DOI: 10.1016/j.lfs.2014.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 08/04/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
AIM Promoter-targeted small activating RNAs (saRNAs) have been shown to be able to induce target gene expression, a mechanism known as RNA activation (RNAa). The present study tested whether saRNA can induce the overexpression of TRPV5 in human cells derived from the kidney and subsequently manipulate cell calcium uptake. MAIN METHODS Three saRNAs complementary to the TRPV5 promoter were synthesized and transfected into cells. TRPV5 expression at the RNA and protein levels was analyzed by quantitative real-time PCR and Western blotting respectively. For functional study, transcellular Ca(2+) transportation was tested by fura-2 analysis. Dihydrotestosterone (DHT), a suppressor of cellular calcium transportation, was administered to challenge the activating effect of selected saRNA. KEY FINDINGS One of these synthesized saRNAs, ds-2939, significantly induced the expression of TRPV5 at both mRNA and protein levels. Fura-2 analysis revealed that the intracellular Ca(2+) concentration was elevated by ds-2939. DHT treatment reduced transmembrane Ca(2+) transport, which was partially antagonized by ds-2939. SIGNIFICANCE Our results suggest that a saRNA targeting TRPV5 promoter can be utilized to manipulate the transmembrane Ca(2+) transport by upregulating the expression of TRPV5 and may serve as an alternative for the treatment of Ca(2+) balance-related diseases.
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Affiliation(s)
- Bicheng Yang
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Xiaolu Duan
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Wenzheng Wu
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Weidong Ji
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Wenqi Wu
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Wen Zhong
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Zhijian Zhao
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Shujue Li
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Yang Liu
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China
| | - Guohua Zeng
- Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou 510230, China.
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25
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Abstract
TRPV5 is one of the two channels in the TRPV family that exhibit high selectivity to Ca(2+) ions. TRPV5 mediates Ca(2+) influx into cells as the first step to transport Ca(2+) across epithelia. The specialized distribution in the distal tubule of the kidney positions TRPV5 as a key player in Ca(2+) reabsorption. The responsiveness in expression and/or activity of TRPV5 to hormones such as 1,25-dihydroxyvitamin D3, parathyroid hormone, estrogen, and testosterone makes TRPV5 suitable for its role in the fine-tuning of Ca(2+) reabsorption. This role is further optimized by the modulation of TRPV5 trafficking and activity via its binding partners; co-expressed proteins; tubular factors such as calbindin-D28k, calmodulin, klotho, uromodulin, and plasmin; extracellular and intracellular factors such as proton, Mg(2+), Ca(2+), and phosphatidylinositol-4,5-bisphosphate; and fluid flow. These regulations allow TRPV5 to adjust its overall activity in response to the body's demand for Ca(2+) and to prevent kidney stone formation. A point mutation in mouse Trpv5 gene leads to hypercalciuria similar to Trpv5 knockout mice, suggesting a possible role of TRPV5 in hypercalciuric disorders in humans. In addition, the single nucleotide polymorphisms in Trpv5 gene prevalently present in African descents may contribute to the efficient renal Ca(2+) reabsorption among African descendants. TRPV5 represents a potential therapeutic target for disorders with altered Ca(2+) homeostasis.
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Affiliation(s)
- Tao Na
- Cell Collection and Research Center, Institute for Biological Product Control, National Institutes for Food and Drug Control, Beijing, China
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26
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Rowlands C, Zyada A, Zouwail S, Joshi H, Stechman MJ, Scott-Coombes DM. Recurrent urolithiasis following parathyroidectomy for primary hyperparathyroidism. Ann R Coll Surg Engl 2013; 95:523-8. [PMID: 24112502 PMCID: PMC5827286 DOI: 10.1308/003588413x13629960048712] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2013] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION The effect of parathyroidectomy on the incidence of recurrent stone formation is uncertain. We aimed to compare the biochemistry and recurrence rate of urolithiasis in patients with primary hyperparathyroidism (pHPT) and stone formation (SF) and non-stone formation (NSF) with idiopathic stone formers (ISF). METHODS Patients with pHPT and SF (Group 1) were identified from a prospective database. pHPT patients and NSF (Group 2) and ISFs (Group 3) were randomly selected from respective databases to form three equal groups. Preoperative and postoperative biochemical data were analysed and recurrent urolithiasis diagnosed if present on follow-up radiology. Out-of-area patients were asked about recurrence via telephone. RESULTS From July 2002 to October 2011, 640 patients had parathyroidectomy for pHPT. Of these, 66 (10.3%) had a history of renal colic; one was lost to follow-up. Patient demographics were similar across all three groups. Three months post-parathyroidectomy, Groups 1 and 2 had significantly reduced serum calcium concentrations (p<0.01). Group 1 had lower urinary calcium excretion after parathyroidectomy (p<0.01), but estimated glomerular filtration rate did not change following surgery. During median follow-up of 4.33 years (0.25-9 years) in Groups 1 and 2 and 5.08 years (0.810-8 years) in Group 3, one patient (1.5%) in Group 1 and 16 patients (25%) in Group 3 had recurrent urolithiasis (p<0.01). No Group 2 patients developed stones. CONCLUSION Curative parathyroidectomy confers a low recurrence rate for urolithiasis, but does not prevent recurrence in all patients. Further research should aim to identify the risk factors for continued SF in these patients.
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Affiliation(s)
- C Rowlands
- Department of Endocrine Surgery, University Hospital of Wales, Cardiff, UK
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27
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Cheng Z, Liang N, Chen TH, Li A, Maria CS, You M, Ho H, Song F, Bikle D, Tu C, Shoback D, Chang W. Sex and age modify biochemical and skeletal manifestations of chronic hyperparathyroidism by altering target organ responses to Ca2+ and parathyroid hormone in mice. J Bone Miner Res 2013; 28:1087-100. [PMID: 23239173 PMCID: PMC3617088 DOI: 10.1002/jbmr.1846] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/15/2012] [Accepted: 11/26/2012] [Indexed: 12/20/2022]
Abstract
We studied mice with or without heterozygous deletion of the Casr in the parathyroid gland (PTG) [(PTG) CaSR(+/-)] to delineate effects of age and sex on manifestations of hyperparathyroidism (HPT). In control mice, aging induced a left-shift in the Ca(2+) /parathyroid hormone (PTH) set point accompanied by increased PTG CaSR expression along with lowered serum Ca(2+) and mildly increased PTH levels, suggesting adaptive responses of PTGs to aging-induced changes in mineral homeostasis. The aging effects on Ca(2+) /PTH set point and CaSR expression were significantly blunted in (PTG) CaSR(+/-) mice, who showed instead progressively elevated PTH levels with age, especially in 12-month-old females. These 12-month-old knockout mice demonstrated resistance to their high PTH levels in that serum 1,25-dihydroxyvitamin D (1,25-D) levels and RNA expression of renal Cyp27b1 and expression of genes involved in Ca(2+) transport in kidney and intestine were unresponsive to the rising PTH levels. Such changes may promote negative Ca(2+) balance, which further exacerbate the HPT. Skeletal responses to HPT were age-, sex-, and site-dependent. In control mice of either sex, trabecular bone in the distal femur decreased whereas cortical bone in the tibiofibular junction increased with age. In male (PTG) CaSR(+/-) mice, anabolic actions of the elevated PTH levels seemed to protect against trabecular bone loss at ≥ 3 months of age at the expense of cortical bone loss. In contrast, HPT produced catabolic effects on trabecular bone and anabolic effects on cortical bone in 3-month-old females; but these effects reversed by 12 months, preserving trabecular bone in aging mice. We demonstrate that the CaSR plays a central role in the adaptive responses of parathyroid function to age-induced changes in mineral metabolism and in target organ responses to calciotropic hormones. Restraining the ability of the PTG to upregulate CaSRs by heterozygous gene deletion contributes to biochemical and skeletal manifestations of HPT, especially in aging females.
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Affiliation(s)
- Zhiqiang Cheng
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Nathan Liang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Tsui-Hua Chen
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Alfred Li
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Christian Santa Maria
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Michael You
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Hanson Ho
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Fuqing Song
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Daniel Bikle
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Chialing Tu
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Dolores Shoback
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
| | - Wenhan Chang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA 94121, USA
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28
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Woudenberg-Vrenken TE, Lameris AL, Weißgerber P, Olausson J, Flockerzi V, Bindels RJM, Freichel M, Hoenderop JGJ. Functional TRPV6 channels are crucial for transepithelial Ca2+ absorption. Am J Physiol Gastrointest Liver Physiol 2012; 303:G879-85. [PMID: 22878123 DOI: 10.1152/ajpgi.00089.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
TRPV6 is considered the primary protein responsible for transcellular Ca2+ absorption. In vitro studies demonstrate that a negatively charged amino acid (D) within the putative pore region of mouse TRPV6 (position 541) is critical for Ca2+ permeation of the channel. To elucidate the role of TRPV6 in transepithelial Ca2+ transport in vivo, we functionally analyzed a TRPV6D541A/D541A knockin mouse model. After weaning, mice were fed a regular (1% wt/wt) or Ca2+-deficient (0.02% wt/wt) diet and housed in metabolic cages. Blood was sampled for Ca2+ measurements, and the expression of Ca2+ transport proteins was analyzed in kidney and duodenum. Intestinal 45Ca2+ uptake was measured in vivo by an absorption assay. Challenging the mice with the Ca2+-deficient diet resulted in hypocalcemia in wild-type and TRPV6D541A/D541A mice. On a low-Ca2+ diet both mouse strains displayed increased expression of intestinal TRPV6, calbindin-D(9K), and renal TRPV5. TRPV6D541A/D541A mice showed significantly impaired intestinal Ca2+ uptake compared with wild-type mice, and duodenal TRPV5 expression was increased in TRPV6D541A/D541A mice. On a normal diet, serum Ca2+ concentrations normalized in both mouse strains. Under these conditions, intestinal Ca2+ uptake was similar, and the expression levels of renal and intestinal Ca2+ transport proteins were not affected. We demonstrate that TRPV6D541A/D541A mice exhibit impaired transcellular Ca2+ absorption. Duodenal TRPV5 expression was increased in TRPV6D541A/D541A mice, albeit insufficient to correct for the diminished Ca2+ absorption. Under normal conditions, when passive Ca2+ transport is predominant, no differences between wild-type and TRPV6D541A/D541A mice were observed. Our results demonstrate a specific role for TRPV6 in transepithelial Ca2+ absorption.
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Affiliation(s)
- Titia E Woudenberg-Vrenken
- Department of Physiology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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29
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Abstract
Calcium is the most abundant cation in the human body, of which approximately 99% occurs in bone, contributing to its rigidity and strength. Bone also functions as a reservoir of Ca for its role in multiple physiologic and biochemical processes. This article aims to provide a thorough understanding of the absorptive mechanisms and factors affecting these processes to enable one to better appreciate an individual's Ca needs, and to provide a rationale for correcting Ca deficiencies. An overview of Ca requirements and suggested dosing regimens is presented, with discussion of various Ca preparations and potential toxicities of Ca treatment.
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Affiliation(s)
- Ronald D Emkey
- Pennsylvania Regional Center for Arthritis & Osteoporosis Research, 1200 Broadcasting Road, Suite 200, Wyomissing, PA 19610, USA.
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30
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Blomberg Jensen M. Vitamin D metabolism, sex hormones, and male reproductive function. Reproduction 2012; 144:135-52. [DOI: 10.1530/rep-12-0064] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The spectrum of vitamin D (VD)-mediated effects has expanded in recent years, and VD is now recognized as a versatile signaling molecule rather than being solely a regulator of bone health and calcium homeostasis. One of the recently identified target areas of VD is male reproductive function. The VD receptor (VDR) and the VD metabolizing enzyme expression studies documented the presence of this system in the testes, mature spermatozoa, and ejaculatory tract, suggesting that both systemic and local VD metabolism may influence male reproductive function. However, it is still debated which cell is the main VD target in the testis and to what extent VD is important for sex hormone production and function of spermatozoa. This review summarizes descriptive studies on testicular VD metabolism and spatial distribution of VDR and the VD metabolizing enzymes in the mammalian testes and discusses mechanistic and association studies conducted in animals and humans. The reviewed evidence suggests some effects of VD on estrogen and testosterone biosynthesis and implicates involvement of both systemic and local VD metabolism in the regulation of male fertility potential.
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31
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Christakos S. Recent advances in our understanding of 1,25-dihydroxyvitamin D(3) regulation of intestinal calcium absorption. Arch Biochem Biophys 2012; 523:73-6. [PMID: 22230327 DOI: 10.1016/j.abb.2011.12.020] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 12/23/2011] [Accepted: 12/26/2011] [Indexed: 02/07/2023]
Abstract
Calcium is required for many cellular processes including muscle contraction, nerve pulse transmission, stimulus secretion coupling and bone formation. The principal source of new calcium to meet these essential functions is from the diet. Intestinal absorption of calcium occurs by an active transcellular path and by a non-saturable paracellular path. The major factor influencing intestinal calcium absorption is vitamin D and more specifically the hormonally active form of vitamin D, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)). This article emphasizes studies that have provided new insight related to the mechanisms involved in the intestinal actions of 1,25(OH)(2)D(3). The following are discussed: recent studies, including those using knock out mice, that suggest that 1,25(OH)(2)D(3) mediated calcium absorption is more complex than the traditional transcellular model; evidence for 1,25(OH)(2)D(3) mediated active transport of calcium by distal as well as proximal segments of the intestine; 1,25(OH)(2)D(3) regulation of paracellular calcium transport and the role of 1,25(OH)(2)D(3) in protection against mucosal injury.
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Affiliation(s)
- Sylvia Christakos
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.
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32
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Transient receptor proteins illuminated: Current views on TRPs and disease. Vet J 2011; 187:153-64. [DOI: 10.1016/j.tvjl.2010.01.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 01/21/2010] [Accepted: 01/25/2010] [Indexed: 11/23/2022]
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Peng JB. TRPV5 and TRPV6 in transcellular Ca(2+) transport: regulation, gene duplication, and polymorphisms in African populations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:239-75. [PMID: 21290300 DOI: 10.1007/978-94-007-0265-3_14] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
TRPV5 and TRPV6 are unique members of the TRP super family. They are highly selective for Ca(2+) ions with multiple layers of Ca(2+)-dependent inactivation mechanisms, expressed at the apical membrane of Ca(2+) transporting epithelia, and robustly responsive to 1,25-dihydroxivitamin D(3). These features are well suited for their roles as Ca(2+) entry channels in the first step of transcellular Ca(2+) transport pathways, which are involved in intestinal absorption, renal reabsorption of Ca(2+), placental transfer of Ca(2+) to fetus, and many other processes. While TRPV6 is more broadly expressed in a variety of tissues such as esophagus, stomach, small intestine, colon, kidney, placenta, pancreas, prostate, uterus, salivary gland, and sweat gland, TRPV5 expression is relatively restricted to the distal convoluted tubule and connecting tubule of the kidney. There is only one TRPV6-like gene in fish and birds in comparison to both TRPV5 and TRPV6 genes in mammals, indicating TRPV5 gene was likely generated from duplication of TRPV6 gene during the evolution of mammals to meet the needs of complex renal function. TRPV5 and TRPV6 are subjected to vigorous regulations under physiological, pathological, and therapeutic conditions. The elevated TRPV6 level in malignant tumors such as prostate and breast cancers makes it a potential therapeutic target. TRPV6, and to a lesser extent TRPV5, exhibit unusually high levels of single nucleotide polymorphisms (SNPs) in African populations as compared to other populations, indicating TRPV6 gene was under selective pressure during or after humans migrated out of Africa. The SNPs of TRPV6 and TRPV5 likely contribute to the Ca(2+) conservation mechanisms in African populations.
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Affiliation(s)
- Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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34
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Takumida M, Ishibashi T, Hamamoto T, Hirakawa K, Anniko M. Age-dependent changes in the expression of klotho protein, TRPV5 and TRPV6 in mouse inner ear. Acta Otolaryngol 2009; 129:1340-50. [PMID: 19922080 DOI: 10.3109/00016480902725254] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS Klotho protein content decreases with increasing age, which weakens resistance to oxidative stress, resulting in induced cell death as well as modulating endolymph fluid homeostasis. Down-regulation of klotho also leads to down-regulation of TRPV5 and TRPV6, resulting in modified Ca(2+) homeostasis in the inner ear, dysfunction of sensory cell transduction and causing hearing loss and/or vestibular disorders. OBJECTIVE Expression of klotho, TRPV5 and TRPV6 in the mouse inner ear and age-related changes were analysed. MATERIALS AND METHODS CBA/J mice aged 8 weeks and 24 months were used in this study. The localization of klotho, TRPV5 and TRPV6 in the inner ear of young and old mice was investigated by immunohistochemistry. RESULTS Immunostaining for klotho was observed in stria vascularis, outer and inner hair cells (OHCs and IHCs), and in vestibular sensory cells and dark cells, and less intensely in the spiral and vestibular ganglion cells. Expression of TRPV5 was found in stria vascularis, organ of Corti, vestibular sensory cells and dark cells, and less intensely in the spiral and vestibular ganglion cells. Expression of TRPV6 was found in supporting cells of the organ of Corti, with weak labelling in OHCs and IHCs. Weak fluorescence was also noted in stria vascularis, and faint fluorescence in the spiral ligament. Vestibular sensory and dark cells as well as vestibular ganglion cells showed weak fluorescence. In the old animals, the expression patterns of klotho, TRPV5 and TRPV6 were identical with those in young animals, although fluorescence intensity was significantly weaker.
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Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Hiroshima University Faculty of Medicine, Hiroshima, Japan.
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35
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Thomson ABR. Small intestinal disorders in the elderly. Best Pract Res Clin Gastroenterol 2009; 23:861-74. [PMID: 19942164 DOI: 10.1016/j.bpg.2009.10.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 10/12/2009] [Accepted: 10/12/2009] [Indexed: 01/31/2023]
Abstract
The topic of gastroenterology (GI) in the elderly has been extensively reviewed. It takes special skill, patience and insight to interview the elderly, as well as to appreciate their altered physiology and interpretation of their presenting symptoms and signs, often against an extreme background of complex medical problems. The maldigestion and malabsorption coupled with altered motility contributes to the development of malnutrition. There generally a decrease of function of the GI tract, but there may be loss of adaptability in response to changes in diet or nutritional stress. Pathological alterations which might lead to minor overall intestinal functional variations in the young because of a normal process of adaptation, may lead to much more serious events in the elderly.
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Affiliation(s)
- Alan B R Thomson
- Division of General Internal Medicine, University of Alberta, Edmonton, AB, Canada.
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36
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Alexander RT, Woudenberg-Vrenken TE, Buurman J, Dijkman H, van der Eerden BCJ, van Leeuwen JPTM, Bindels RJ, Hoenderop JG. Klotho prevents renal calcium loss. J Am Soc Nephrol 2009; 20:2371-9. [PMID: 19713312 DOI: 10.1681/asn.2008121273] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Disturbed calcium (Ca(2+)) homeostasis, which is implicit to the aging phenotype of klotho-deficient mice, has been attributed to altered vitamin D metabolism, but alternative possibilities exist. We hypothesized that failed tubular Ca(2+) absorption is primary, which causes increased urinary Ca(2+) excretion, leading to elevated 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] and its sequelae. Here, we assessed intestinal Ca(2+) absorption, bone densitometry, renal Ca(2+) excretion, and renal morphology via energy-dispersive x-ray microanalysis in wild-type and klotho(-/-) mice. We observed elevated serum Ca(2+) and fractional excretion of Ca(2+) (FE(Ca)) in klotho(-/-) mice. Klotho(-/-) mice also showed intestinal Ca(2+) hyperabsorption, osteopenia, and renal precipitation of calcium-phosphate. Duodenal mRNA levels of transient receptor potential vanilloid 6 (TRPV6) and calbindin-D(9K) increased. In the kidney, klotho(-/-) mice exhibited increased expression of TRPV5 and decreased expression of the sodium/calcium exchanger (NCX1) and calbindin-D(28K), implying a failure to absorb Ca(2+) through the distal convoluted tubule/connecting tubule (DCT/CNT) via TRPV5. Gene and protein expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D-1-alpha-hydroxylase (1alphaOHase), and calbindin-D(9K) excluded renal vitamin D resistance. By modulating the diet, we showed that the renal Ca(2+) wasting was not secondary to hypercalcemia and/or hypervitaminosis D. In summary, these findings illustrate a primary defect in tubular Ca(2+) handling that contributes to the precipitation of calcium-phosphate in DCT/CNT. This highlights the importance of klotho to the prevention of renal Ca(2+) loss, secondary hypervitaminosis D, osteopenia, and nephrocalcinosis.
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Affiliation(s)
- R Todd Alexander
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, , 6500 HB Nijmegen, The Netherlands
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Lee BM, Lee GS, Jung EM, Choi KC, Jeung EB. Uterine and placental expression of TRPV6 gene is regulated via progesterone receptor- or estrogen receptor-mediated pathways during pregnancy in rodents. Reprod Biol Endocrinol 2009; 7:49. [PMID: 19457270 PMCID: PMC2694200 DOI: 10.1186/1477-7827-7-49] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 05/21/2009] [Indexed: 12/22/2022] Open
Abstract
Transient receptor potential cation channel, subfamily V, member 6 (TRPV6) is an epithelial Ca2+ channel protein expressed in calcium absorbing organs. In the present study, we investigated the expression and regulation of uterine and placental TRPV6 during gestation in rodents. Uterine TRPV6 peaked at pregnancy day (P) 0.5, P5.5 and, P13.5 and was detected in uterine epithelium and glands of rats, while placental TRPV6 mRNA levels increased in mid-gestation. Uterine and placental TRPV6 mRNA levels in rats appear to cyclically change during pregnancy, suggesting that TRPV6 may participate in the implantation process. In addition, uterine TRPV6 mRNA is only expressed in placenta-unattached areas of the uterus, and uterine TRPV6 immunoreactivity was observed in luminal and glandular epithelial cells. In the placenta, TRPV6 was detected in the labyrinth and spongy zone. These results may indicate that TRPV6 has at least two functions: implantation of the embryo and maintenance of pregnancy. To investigate the pathway(s) mediating TRPV6 expression in rodents, anti-steroid hormone antagonists were injected prior to maximal TRPV6 expression. In rats, TRPV6 expression was reduced by RU486 (an anti-progesterone) through progesterone receptors, and ICI 182,780 (an anti-estrogen) blocked TRPV6 expression via estrogen receptors in mice. The juxtaposition of uterine and placental TRPV6 expressed in these tissues supports the notion that TRPV6 participates in transferring calcium ions between the maternal and fetal compartments. Taken together, TRPV6 gene may function as a key element in controlling calcium transport in the uterus between the embryo and the placenta during pregnancy.
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Affiliation(s)
- Bo-Mi Lee
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Geun-Shik Lee
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Eui-Man Jung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Kyung-Chul Choi
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, 361-763, Republic of Korea
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Ageing and vitamin D deficiency: effects on calcium homeostasis and considerations for vitamin D supplementation. Br J Nutr 2009; 101:1597-606. [PMID: 19393111 DOI: 10.1017/s0007114509338842] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vitamin D is a fat-soluble, seco-steroid hormone. In man, the vitamin D receptor is expressed in almost all tissues, enabling effects in multiple systems of the human body. These effects can be endocrine, paracrine and autocrine. The present review summarises the effects of ageing on the vitamin D endocrine system and on Ca homeostasis. Furthermore, consequences for vitamin D supplementation are discussed.
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Abstract
1. Calcium (re)absorption occurs in epithelia, including the intestine, kidney, mammary glands, placenta and gills (in the case of fish). 2. Calcium is transported across epithelia by two transport mechanisms, paracellular and transcellular, and the movement is regulated by a complex array of transport processes that are mediated by hormonal, developmental and physiological factors involving the gastrointestinal tract, bone, kidney and the parathyroids. 3. Clear understanding of the calcium transport pathways and their endocrine regulation is critical for minimizing various metabolic and health disorders at different physiological stages. Here, we first briefly review the calcium transport mechanisms before discussing in detail the endocrine factors that regulate calcium transport in the epithelia.
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Affiliation(s)
- Ramesh C Khanal
- Department of Food Science, University of Arkansas, Fayetteville, Arizona, Utah State University, Logan, Utah, USA
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Responses of parathyroid hormone to vitamin D supplementation: a systematic review of clinical trials. Arch Gerontol Geriatr 2008; 48:160-6. [PMID: 18243368 DOI: 10.1016/j.archger.2007.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 12/04/2007] [Accepted: 12/08/2007] [Indexed: 11/21/2022]
Abstract
The beneficial bone effects of vitamin D supplementation have been attributed to suppression of secondary hyperparathyroidism by 25-hydroxyvitamin D (25-OHD) levels at least 50nmol/l. In this systematic review, we have analyzed the results of 52 clinical trials, including 72 intervention groups and 6290 patients, on vitamin D supplementation in order to evaluate the experimental evidence and the effects of age and chronic immobility on responses of parathyroid hormone (PTH). The papers for this systematic review were selected through a search in PubMed and through a review of the reference lists of articles. Negative logarithmic (R(2)=0.318, p<0.001) and linear (R(2)=0.294, p<0.001) correlations were found between 25-OHD and PTH levels, when all pre- and post-trial values were scattered. Negative linear (R(2)=0.385, p<0.001) and logarithmic (R(2)=0.406, p<0.001) correlations were also found between the changes in 25-OHD and PTH levels. Age correlated negatively with changes in PTH (r=-0.476, p<0.001). The vitamin D supplementation of the chronically immobile patients resulted in a smaller decrease in PTH levels (-8.4 vs. -17.4%, p<0.001) despite a larger increase in 25-OHD levels (187.2% vs. 109.8%, p<0.001). According to the multiple regression analysis the changes in PTH were independently predicted by pre-trial PTH, changes in 25-OHD, age and chronic immobility, explaining 53.2% (R(2)=0.532) of the variation. This meta-analysis shows that responses of PTH to vitamin D supplementation are not only determined by the baseline PTH levels and changes in vitamin D status, but also by age and mobility of the patients. Our results also suggest that PTH decreases quite linearly during vitamin D supplementation at any given 25-OHD level. Longitudinal vitamin D supplementation studies on populations with wide range of mobility and age are needed to further elucidate their confounding effects. In determining the sufficient doses of vitamin D supplementation and adequate 25-OHD levels, these confounding effects and the inter-individual variation in responses of PTH to vitamin D supplementation should be taken into account.
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Tordoff MG. Taste solution preferences of C57BL/6J and 129X1/SvJ mice: influence of age, sex, and diet. Chem Senses 2007; 32:655-71. [PMID: 17566070 PMCID: PMC2486361 DOI: 10.1093/chemse/bjm034] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
To examine whether age influences taste solution preferences, we measured taste preferences of C57BL/6J and 129X1/SvJ mice given a series of 48-h 2-bottle tests with a choice between water and one of the following taste solutions: 2 mM saccharin, 5 mM citric acid, 30 microM quinine hydrochloride, 75 mM sodium chloride (NaCl), 10 mM inosine monophosphate (IMP), 50 mM calcium chloride (CaCl(2)), and 10% ethanol. We tested separate groups of male mice fed Teklad 8604 chow at ages 4, 6, 9, 12, 15, 20, 25, 30, 40, and 50 weeks and retested some of these mice at 54, 75, and 100 weeks and again at 125 weeks. Female mice fed chow were tested at ages 4, 12, 25, and 50 weeks and retested at 54, 75, 100, and 125 weeks. Male mice fed AIN-93G semisynthetic diet were tested at ages 4, 12, 25, and 50 weeks and retested at 54, 75, and 100 weeks. Concentration-response functions for each taste solution were collected from male and female mice fed chow aged 8 or 125 weeks. In general, the results showed that age had little effect on taste preferences. Exceptions included 1) a small increase in quinine hydrochloride preference between 54 and 125 weeks in mice of both strains and sexes, 2) a marked increase in NaCl preference between 4 and 12 weeks in female B6 mice, 3) a gradual decrease in IMP preference between 4 and 125 weeks in male and female 129 mice, 4) a marked decrease in CaCl(2) preference between 54 and 125 weeks in male and female 129 mice, and 5) a marked reduction in ethanol preference between 4 and 12 weeks in male B6 mice fed AIN-93G diet but not chow. These results show that over a wide range and with the exceptions noted, age contributes little to the variation in taste preferences observed in C57BL/6J and 129X1/SvJ mice.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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van de Graaf SFJ, Bindels RJM, Hoenderop JGJ. Physiology of epithelial Ca2+ and Mg2+ transport. Rev Physiol Biochem Pharmacol 2007; 158:77-160. [PMID: 17729442 DOI: 10.1007/112_2006_0607] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ca2+ and Mg2+ are essential ions in a wide variety of cellular processes and form a major constituent of bone. It is, therefore, essential that the balance of these ions is strictly maintained. In the last decade, major breakthrough discoveries have vastly expanded our knowledge of the mechanisms underlying epithelial Ca2+ and Mg2+ transport. The genetic defects underlying various disorders with altered Ca2+ and/or Mg2+ handling have been determined. Recently, this yielded the molecular identification of TRPM6 as the gatekeeper of epithelial Mg2+ transport. Furthermore, expression cloning strategies have elucidated two novel members of the transient receptor potential family, TRPV5 and TRPV6, as pivotal ion channels determining transcellular Ca2+ transport. These two channels are regulated by a variety of factors, some historically strongly linked to Ca2+ homeostasis, others identified in a more serendipitous manner. Herein we review the processes of epithelial Ca2+ and Mg2+ transport, the molecular mechanisms involved, and the various forms of regulation.
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Affiliation(s)
- S F J van de Graaf
- Radboud University Nijmegen Medical Centre, 286 Cell Physiology, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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