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Koo KC, Halawani A, Wong VK, Lange D, Chew BH. Monogenic features of urolithiasis: A comprehensive review. Asian J Urol 2024; 11:169-179. [PMID: 38680588 PMCID: PMC11053333 DOI: 10.1016/j.ajur.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 03/28/2023] [Indexed: 05/01/2024] Open
Abstract
Objective Urolithiasis formation has been attributed to environmental and dietary factors. However, evidence is accumulating that genetic background can contribute to urolithiasis formation. Advancements in the identification of monogenic causes using high-throughput sequencing technologies have shown that urolithiasis has a strong heritable component. Methods This review describes monogenic factors implicated in a genetic predisposition to urolithiasis. Peer-reviewed journals were evaluated by a PubMed search until July 2023 to summarize disorders associated with monogenic traits, and discuss clinical implications of identification of patients genetically susceptible to urolithiasis formation. Results Given that more than 80% of urolithiases cases are associated with calcium accumulation, studies have focused mainly on monogenetic contributors to hypercalciuric urolithiases, leading to the identification of receptors, channels, and transporters involved in the regulation of calcium renal tubular reabsorption. Nevertheless, available candidate genes and linkage methods have a low resolution for evaluation of the effects of genetic components versus those of environmental, dietary, and hormonal factors, and genotypes remain undetermined in the majority of urolithiasis formers. Conclusion The pathophysiology underlying urolithiasis formation is complex and multifactorial, but evidence strongly suggests the existence of numerous monogenic causes of urolithiasis in humans.
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Affiliation(s)
- Kyo Chul Koo
- Department of Urology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | | | - Victor K.F. Wong
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Dirk Lange
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Ben H. Chew
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
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2
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Luo W, Zhang G, Wang Z, Wu Y, Xiong Y. Ubiquitin-specific proteases: Vital regulatory molecules in bone and bone-related diseases. Int Immunopharmacol 2023; 118:110075. [PMID: 36989900 DOI: 10.1016/j.intimp.2023.110075] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/06/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023]
Abstract
Stabilization of bone structure and function involves multiple cell-to-cell and molecular interactions, in which the regulatory functions of post-translational modifications such as ubiquitination and deubiquitination shouldn't be underestimated. As the largest family of deubiquitinating enzymes, the ubiquitin-specific proteases (USPs) participate in the development of bone homeostasis and bone-related diseases through multiple classical osteogenic and osteolytic signaling pathways, such as BMP/TGF-β pathway, NF-κB/p65 pathway, EGFR-MAPK pathway and Wnt/β-catenin pathway. Meanwhile, USPs may also broadly regulate regulate hormone expression level, cell proliferation and differentiation, and may further influence bone homeostasis from gene fusion and nuclear translocation of transcription factors. The number of patients with bone-related diseases is currently enormous, making exploration of their pathogenesis and targeted therapy a hot topic. Pathological increases in the levels of inflammatory mediators such as IL-1β and TNF-α lead to inflammatory bone diseases such as osteoarthritis, rheumatoid arthritis and periodontitis. While impaired body metabolism greatly increases the probability of osteoporosis. Abnormal physiological activity of bone-associated cells results in a variety of bone tumors. The regulatory role of USPs in bone-related disease has received particular attention from academics in recent studies. In this review, we focuse on the roles and mechanisms of USPs in bone homeostasis and bone-related diseases, with the expectation of informing targeted therapies in the clinic.
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Affiliation(s)
- Wenxin Luo
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Guorui Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhanqi Wang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yingying Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yi Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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3
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Osman O, Manzi S, Wasko MC, Clark BA. Case report: disease mechanisms and medical management of calcium nephrolithiasis in rheumatologic diseases. BMC Urol 2023; 23:42. [PMID: 36959633 PMCID: PMC10035194 DOI: 10.1186/s12894-023-01203-y] [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: 08/16/2021] [Accepted: 02/19/2023] [Indexed: 03/25/2023] Open
Abstract
Background Nephrolithiasis as a feature of rheumatologic diseases is under recognized. Understanding presenting features, diagnostic testing is crucial to proper management. Case presentation A 32 year old woman with a history of recurrent complicated nephrolithiasis presented to a rheumatologist for a several month history of fatigue, dry eyes, dry mouth, arthralgias. She had a positive double-stranded DNA, positive SSA and SSB antibodies. She was diagnosed with Systemic Lupus erythematosus (SLE) and Sjogren's syndrome and was started on mycophenalate mofetil. Of relevance was a visit to her local emergency room 4 years earlier with profound weakness with unexplained marked hypokalemia and a non-anion gap metabolic acidosis. Approximately one year after that episode she developed flank pain and nephrocalcinosis. She had multiple issues over the ensuing years with stones and infections on both sides. Interventions included extracorporeal shockwave lithotripsy as well as open lithotomy and eventual auto-transplantation of left kidney for recurrent ureteric stenosis. 24 h stone profile revealed marked hypocitraturia, normal urine calcium, normal urine oxalate and uric acid. She was treated with potassium citrate. Mycophenolate was eventually stopped due to recurrent urinary tract infections and she was started on Belimumab. Because of recurrent SLE flares, treatment was changed to Rituximab (every 6 months) with clinical and serologic improvement. Her kidney stone frequency gradually improved and no further interventions needed although she continued to require citrate repletion for hypocitraturia. Conclusions Nephrolithiasis can be a prominent and even presenting feature in Sjogrens syndrome as well as other rheumatologic diseases. Prompt recognition and understanding disease mechanisms is important for best therapeutic interventions for kidney stone prevention as well as treatment of underlying bone mineral disease.
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Affiliation(s)
- Omar Osman
- grid.417046.00000 0004 0454 5075Department of Medicine, Allegheny Health Network, 320 East North Ave, Pittsburgh, PA 15212 USA
| | - Susan Manzi
- grid.417046.00000 0004 0454 5075Department of Medicine, Allegheny Health Network, 320 East North Ave, Pittsburgh, PA 15212 USA
| | - Mary Chester Wasko
- grid.417046.00000 0004 0454 5075Department of Medicine, Allegheny Health Network, 320 East North Ave, Pittsburgh, PA 15212 USA
| | - Barbara A. Clark
- grid.417046.00000 0004 0454 5075Department of Medicine, Allegheny Health Network, 320 East North Ave, Pittsburgh, PA 15212 USA
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Singh P, Harris PC, Sas DJ, Lieske JC. The genetics of kidney stone disease and nephrocalcinosis. Nat Rev Nephrol 2022; 18:224-240. [PMID: 34907378 DOI: 10.1038/s41581-021-00513-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 12/15/2022]
Abstract
Kidney stones (also known as urinary stones or nephrolithiasis) are highly prevalent, affecting approximately 10% of adults worldwide, and the incidence of stone disease is increasing. Kidney stone formation results from an imbalance of inhibitors and promoters of crystallization, and calcium-containing calculi account for over 80% of stones. In most patients, the underlying aetiology is thought to be multifactorial, with environmental, dietary, hormonal and genetic components. The advent of high-throughput sequencing techniques has enabled a monogenic cause of kidney stones to be identified in up to 30% of children and 10% of adults who form stones, with ~35 different genes implicated. In addition, genome-wide association studies have implicated a series of genes involved in renal tubular handling of lithogenic substrates and of inhibitors of crystallization in stone disease in the general population. Such findings will likely lead to the identification of additional treatment targets involving underlying enzymatic or protein defects, including but not limited to those that alter urinary biochemistry.
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Affiliation(s)
- Prince Singh
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Molecular Biology and Biochemistry, Mayo Clinic, Rochester, MN, USA
| | - David J Sas
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Pediatric Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA. .,Division of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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5
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[Nephrocalcinosis in children]. Nephrol Ther 2021; 17:58-66. [PMID: 33461896 DOI: 10.1016/j.nephro.2020.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nephrocalcinosis is defined by calcium phosphate or calcium oxalate deposits in the kidney parenchyma, particularly in tubular epithelial cells and interstitial tissue. It should be differentiated from urolithiasis where calcium salts deposits are located in the kidney and urinary tract. The epidemiology of nephrocalcinosis in children is unknown but the condition is not so rare, with an increased incidence in preterm infants. Often detected as an incidental finding, nephrocalcinosis may be classified according to the radiological type: medullary, cortical or diffuse. Nephrocalcinosis in children can be caused by a variety of etiology. The most common causes concern medullary nephrocalcinosis and include hereditary tubular disorders, in particular distal renal tubular acidosis and Dent disease, metabolic disorders such as idiopathic hypercalciuria and hyperoxaluria, and iatrogenic causes such as vitamin D intoxication. In the newborn, the main cause is hypercalciuria of the premature baby, whose multifactorial origin is largely iatrogenic. Primary hyperoxaluria which can lead to early onset nephrocalcinosis and usually to chronic kidney disease should always be considered and further investigated. In order to provide a specific diagnosis, it is essential to take into account the family history, the clinical context and complete laboratory data. Early initiation of an appropriate etiological treatment is recommended and may prevent or delay the progression to chronic kidney disease in some cases.
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Effect of parathyroidectomy on renal stone recurrence. Urolithiasis 2021; 49:327-334. [PMID: 33420577 DOI: 10.1007/s00240-020-01239-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/17/2020] [Indexed: 10/22/2022]
Abstract
Parathyroidectomy (PTX) is routinely performed in hypercalciuric renal stone patients with primary hyperparathyroidism (PHPT). However, some data indicate a persistent stone activity following PTX, raising the issue of the link between PHPT and stone disease. We performed an observational study on 30 renal stone patients diagnosed with PHPT. Patients were selected among 1448 hypercalciuric patients referred in our department for a diagnostic evaluation. Patients with no parathyroid surgery or any biological follow-up were excluded. Clinical and biological data (including 24-h urine collection and a calcium load test) were collected before and within 12 months following surgery. Stone recurrence was evaluated by direct phone contact (median 43 months). Comparison of biological data before and after surgery showed a significant decrease of ionized calcium and serum parathyroid hormone after PTX. All stones contained calcium-dependent species such as carbapatite, brushite or dihydrate calcium oxalate. Urine saturation indexes and calciuria significantly decreased after surgery (from 9.9 to 5.9 mmol/d, p < 0.0001), but a persistent hypercalciuria was detected in 47% of patients. The other stone risk factors including diuresis stayed similar. Stone activity that was increasing (from 0.20-0.30 to 0.50-0.75/year) the 2 years before PTX, significantly decreased after surgery [0.05-0.15/year (p < 0.001)]. PTX in calcium-dependent renal stone formers with PHPT significantly decreases both stone recurrence and urine saturation indexes. However, PTX unmasked an underlying renal stone disease related to idiopathic hypercalciuria in half of patients with a remaining stone activity, testifying the need for patient's follow-up to prevent stone recurrence.
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The interest of oral calcium loads test in the diagnosis and management of pediatric nephrolithiasis with hypercalciuria: Experience from a tertiary pediatric centre. J Pediatr Urol 2020; 16:489.e1-489.e9. [PMID: 32593617 DOI: 10.1016/j.jpurol.2020.05.160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/30/2020] [Accepted: 05/22/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION The use of calcium load has been forgotten in pediatrics until recently whereas it is of utmost importance to have a practical approach to guide management of hypercalciuric nephrolithiasis. OBJECTIVE The purpose of this study was to evaluate the practical interest of oral calcium loads to improve the overall management of nephrolithiasis in children. METHODS We retrospectively studied all pediatric patients having undergone an oral calcium load in our pediatric nephrology unit between September 2015 and April 2017. RESULTS A total of 16 patients were included, at a median age of 12.0 (5.5-17.5) years. The indications of oral calcium load were: presence of an active urolithiasis without any obvious explanation after ruling out the "classical" biological abnormalities, or presence of hypercalciuria with stones composed of weddellite or carbapatite crystals. Among the 16 patients, 6 (38%) patients displayed absorptive hypercalciuria, 2 (12%) renal leak, 3 (19%) "unclassified" inadapted PTH, and 5 (31%) a normal calcium load test. The result of oral calcium load modified the clinical management in 14 (88%) patients, mainly based on the type of hypercalciuria. It allowed us to individualize nutritional advice: in patients with absorptive hypercalciuria, we proposed calcium intake within the lower normal range for age with dairy products not enriched with vitamin D, with the advice to avoid salt and calcium loads during evenings. Conversely, in patients with resorptive hypercalciuria, we proposed normal calcium intake for age. Showing the results of the calcium load is meaningful to patients and parents, and can be considered as an "educational" tool. DISCUSSION To the best of our knowledge, this study is the first to evaluate the interest of calcium load in children with nephrolithiasis in an era of routine PTH and 1-25-D assessment. Here, we demonstrate the feasibility and safety of oral calcium load in children, its interest to understand the underlying mechanisms of hypercalciuria, and its major interest as an "educational tool" for patients to explain them the underlying mechanisms and thus guide the therapeutic management using an individualized dietary approach. This study did not include many patients, but to the best of our knowledge, this is the first study evaluating and validating the feasibility of a safe and non-expensive diagnosis tool in pediatric hypercalciuria. CONCLUSION Oral calcium load is helpful to guide therapeutic adaptation in pediatrics using an individualized dietary approach.
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8
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Expression of vitamin D receptor, CYP27B1 and CYP24A1 hydroxylases and 1,25-dihydroxyvitamin D3 levels in stone formers. Urolithiasis 2019; 48:19-26. [DOI: 10.1007/s00240-019-01163-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/16/2019] [Indexed: 01/16/2023]
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9
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Figueres L, Hourmant M, Lemoine S. Understanding and managing hypercalciuria in adults with nephrolithiasis: keys for nephrologists. Nephrol Dial Transplant 2019; 35:573-575. [DOI: 10.1093/ndt/gfz099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lucile Figueres
- CHU Nantes – Service de Nephrologie, Nantes Cedex, France
- Centre de Recherche en Transplantation et Immunologie, Universite de Nantes – ITUN, Nantes, Pays de la Loire, France
| | - Maryvonne Hourmant
- CHU Nantes – Service de Nephrologie, Nantes Cedex, France
- Centre de Recherche en Transplantation et Immunologie, Universite de Nantes – ITUN, Nantes, Pays de la Loire, France
| | - Sandrine Lemoine
- Hôpital Edouard Herriot, Service de Nephrologie et d'explorations fonctionnelles rénales, Lyon, Rhone Alpes, France
- Universite Claude Bernard Lyon 1–INSERM CARMEN, Universite de Lyon, Lyon, France
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10
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García Nieto VM, Luis Yanes MI, Tejera Carreño P, Perez Suarez G, Moraleda Mesa T. The idiopathic hypercalciuria reviewed. Metabolic abnormality or disease? Nefrologia 2019; 39:592-602. [PMID: 31160051 DOI: 10.1016/j.nefro.2019.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/02/2019] [Accepted: 02/20/2019] [Indexed: 02/08/2023] Open
Abstract
Idiopathic hypercalciuria (IH) is defined as that clinical situation in which an increase in urinary calcium excretion is observed, in the absence of hypercalcemia and other known causes of hypercalciuria. In recent years, its diagnosis in pediatric age has been more frequent because it has been known that it can debut with very different symptoms, in the absence of kidney stone formation. The discovery of genetic hypercalciuric stone-forming rats has allowed us to glimpse the pathophysiological mechanism of IH since they show many data in common with humans with IH as normal levels of blood calcium, intestinal calcium hyperabsorption, increased bone resorption and a defect in the renal tubular calcium reabsorption. In 1993, it was shown that in these animals there is an increase in the number of vitamin D receptors (VDR) in the intestine, which favors an increase in the functional capacity of calcitriol-VDR complexes that explains the increase in intestinal transport of calcium. The same happens at the bone level producing a greater resorption. In our opinion, IH is a 'metabolic anomaly' or, better, an inheritable constitutive metabolic characteristic. In this sense, what patients with IH would inherit is the availability of having a greater number of VDRs in their cells than those with normal urinary calcium excretion. IH cannot be considered a sensu stricto disease, so pharmacological treatment must be individualized.
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Affiliation(s)
- Víctor M García Nieto
- Sección de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, España.
| | - María Isabel Luis Yanes
- Sección de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, España
| | - Patricia Tejera Carreño
- Sección de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, España
| | - German Perez Suarez
- Servicio de Nefrología, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria, España
| | - Teresa Moraleda Mesa
- Sección de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, España
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Krieger NS, Asplin JR, Granja I, Ramos FM, Flotteron C, Chen L, Wu TT, Grynpas MD, Bushinsky DA. Chlorthalidone Is Superior to Potassium Citrate in Reducing Calcium Phosphate Stones and Increasing Bone Quality in Hypercalciuric Stone-Forming Rats. J Am Soc Nephrol 2019; 30:1163-1173. [PMID: 31101664 DOI: 10.1681/asn.2018101066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/14/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The pathophysiology of genetic hypercalciuric stone-forming rats parallels that of human idiopathic hypercalciuria. In this model, all animals form calcium phosphate stones. We previously found that chlorthalidone, but not potassium citrate, decreased stone formation in these rats. METHODS To test whether chlorthalidone and potassium citrate combined would reduce calcium phosphate stone formation more than either medication alone, four groups of rats were fed a fixed amount of a normal calcium and phosphorus diet, supplemented with potassium chloride (as control), potassium citrate, chlorthalidone (with potassium chloride to equalize potassium intake), or potassium citrate plus chlorthalidone. We measured urine every 6 weeks and assessed stone formation and bone quality at 18 weeks. RESULTS Potassium citrate reduced urine calcium compared with controls, chlorthalidone reduced it further, and potassium citrate plus chlorthalidone reduced it even more. Chlorthalidone increased urine citrate and potassium citrate increased it even more; the combination did not increase it further. Potassium citrate, alone or with chlorthalidone, increased urine calcium phosphate supersaturation, but chlorthalidone did not. All control rats formed stones. Potassium citrate did not alter stone formation. No stones formed with chlorthalidone, and rats given potassium citrate plus chlorthalidone had some stones but fewer than controls. Rats given chlorthalidone with or without potassium citrate had higher bone mineral density and better mechanical properties than controls, whereas those given potassium citrate did not. CONCLUSIONS In genetic hypercalciuric stone-forming rats, chlorthalidone is superior to potassium citrate alone or combined with chlorthalidone in reducing calcium phosphate stone formation and improving bone quality.
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Affiliation(s)
- Nancy S Krieger
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York;
| | - John R Asplin
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois
| | - Ignacio Granja
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois
| | - Felix M Ramos
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Courtney Flotteron
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Luojing Chen
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Tong Tong Wu
- Department of Biostatistics and Computational Biology, University of Rochester School of Medicine, Rochester, New York; and
| | - Marc D Grynpas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - David A Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
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12
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Groth EM, Lulich JP, Chew DJ, Parker VJ, Furrow E. Vitamin D metabolism in dogs with and without hypercalciuric calcium oxalate urolithiasis. J Vet Intern Med 2019; 33:758-763. [PMID: 30851134 PMCID: PMC6430952 DOI: 10.1111/jvim.15442] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 01/23/2019] [Indexed: 01/28/2023] Open
Abstract
Background There are abnormalities in vitamin D metabolism in people with calcium nephrolithiasis, but limited data are available on vitamin D status in dogs with calcium oxalate (CaOx) urolithiasis. Objective To compare serum concentrations of vitamin D metabolites in dogs with and without hypercalciuric CaOx urolithiasis. Animals Thirty‐eight dogs with (n = 19) and without (n = 19) a history of CaOx urolithiasis and hypercalciuria. Methods Retrospective cross‐sectional study. Serum 25‐hydroxyvitamin D [25(OH)D], 1,25‐dihydroxyvitamin D [1,25(OH)2D], and 24,25‐dihydroxyvitamin D [24,25(OH)2D] were measured. The ratios of 25(OH)D/24,25(OH)2D and 1,25(OH)2D/25(OH)D were compared between cases and controls. Results There were no significant differences between cases and controls when comparing 25(OH)D, 24,25(OH)2D, 1,25(OH)2D, or 1,25(OH)2D/25(OH)D. Cases had higher 25(OH)D/24,25(OH)2D (median = 1.40, range = 0.98‐1.58) compared to controls (median = 1.16, range = 0.92‐2.75; P = .01). There was overlap in the ranges for 25(OH)D/24,25(OH)2D between cases and controls, but 6 cases (32%) had ratios above the control dog range. There was a moderate positive correlation between the ratio of 25(OH)D/24,25(OH)2D and urinary calcium‐to‐creatinine ratios (r = 0.40, 95% confidence interval = 0.10‐0.64; P = .01). Conclusions and Clinical Importance These data suggest that decreased conversion of 25(OH)D to 24,25(OH)2D occurs in a subset of dogs with CaOx urolithiasis. Abnormalities in vitamin D metabolism might contribute to stone risk in dogs.
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Affiliation(s)
- Elizabeth M Groth
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
| | - Jody P Lulich
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
| | - Dennis J Chew
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Valerie J Parker
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Eva Furrow
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
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13
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Bone resorption in dogs with calcium oxalate urolithiasis and idiopathic hypercalciuria. Res Vet Sci 2019; 123:129-134. [PMID: 30641472 DOI: 10.1016/j.rvsc.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/26/2018] [Accepted: 01/03/2019] [Indexed: 11/23/2022]
Abstract
People with calcium oxalate (CaOx) urolithiasis and idiopathic hypercalciuria (IH) often have evidence of increased bone resorption, but bone turnover has not previously been investigated in dogs with these conditions. The aim of this study was to determine whether a marker of bone resorption, β-crosslaps, differs between dogs with CaOx urolithiasis and IH compared to controls. This retrospective, cross-sectional study used a canine specific ELISA to measure β-crosslaps concentrations in stored frozen serum samples from 20 dogs with CaOx urolithiasis and IH and 20 breed-, sex-, and age-matched stone-free controls (18 Miniature Schnauzers, 14 Bichons Frise, and 8 Shih Tzus). Dogs with CaOx urolithiasis and IH had lower β-crosslaps concentrations relative to controls (P = .0043), and β-crosslaps had a moderate negative correlation with urinary calcium-to-creatinine ratios (r = -0.44, P = .0044). Miniature Schnauzers had lower β-crosslaps concentrations than the other two breeds (P = .0035). The ELISA had acceptable intra-assay precision, but concentrations decreased when samples were repeatedly assayed over time. Assay recovery rates were also below acceptance criteria. In conclusion, Miniature Schnauzers, Bichons Frise, and Shih Tzus with CaOx urolithiasis and IH have evidence of decreased bone resorption compared to stone-free controls. This suggests that other causes of IH, such as intestinal hyperabsorption of calcium, underlie risk for CaOx urolithiasis in these breeds. Results should be confirmed in larger populations and with other β-crosslaps assays and additional biomarkers of bone turnover. The stability of canine serum β-crosslaps after freeze-thaw cycles and storage at various temperatures requires investigation.
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Abstract
Calcium kidney stones are common worldwide. Most are idiopathic and composed of calcium oxalate. Calcium phosphate is present in around 80% and may initiate stone formation. Stone production is multifactorial with a polygenic genetic contribution. Phosphaturia is found frequently among stone formers but until recently received scant attention. This review examines possible mechanisms for the phosphaturia and its relevance to stone formation from a wide angle. There is a striking lack of clinical data. Phosphaturia is associated, but not correlated, with hypercalciuria, increased 1,25 dihydroxy-vitamin D [1,25 (OH)2D], and sometimes evidence of disturbances in proximal renal tubular function. Phosphate reabsorption in the proximal renal tubules requires tightly regulated interaction of many proteins. Paracellular flow through intercellular tight junctions is the major route of phosphate absorption from the intestine and can be reduced therapeutically in hyperphosphatemic patients. In monogenic defects stones develop when phosphaturia is associated with hypercalciuria, generally explained by increased 1,25 (OH)2D production in response to hypophosphatemia. Calcification does not occur in disorders with increased FGF23 when phosphaturia occurs in isolation and 1,25 (OH)2D is suppressed. Candidate gene studies have identified mutations in the phosphate transporters, but in few individuals. One genome-wide study identified a polymorphism of the phosphate transporter gene SLC34A4 associated with stones. Others did not find mutations obviously linked to phosphate reabsorption. Future genetic studies should have a wide trawl and should focus initially on groups of patients with clearly defined phenotypes. The global data should be pooled.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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15
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Urinary proteome in inherited nephrolithiasis. Urolithiasis 2018; 47:91-98. [DOI: 10.1007/s00240-018-01104-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/08/2018] [Indexed: 12/18/2022]
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Abstract
Renal stone disease is a worldwide problem which carries significant morbidity. It frequently requires specialist urology intervention. Patients with recurrent disease and those at high risk require specialist investigations and review. Certain cases benefit from medical and surgical intervention. In this review, we discuss the pathophysiology, risk assessment, specialist investigations and various interventions, their rationale and evidence base. This review aims to provide an update of the previous publication in 2001 in this journal on this topic.
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Affiliation(s)
- Adie Viljoen
- Department of Chemical Pathology, Lister Hospital, Stevenage UK
| | - Rabia Chaudhry
- Department of Chemical Pathology, Lister Hospital, Stevenage UK
| | - John Bycroft
- Department of Urology, Lister Hospital, Stevenage, UK
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17
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Bicarbonate : de la physiologie aux applications thérapeutiques pour tout clinicien. Nephrol Ther 2018; 14:13-23. [DOI: 10.1016/j.nephro.2017.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 11/17/2022]
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18
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Abstract
BACKGROUND Urinary supersaturation is one key determinant of calcium oxalate (CaOx) urinary stone formation, and urinary excretions of oxalate and citrate are two key determinants. Each is influenced by gastrointestinal processes. METHODS Open label and randomized placebo studies have examined the effect of oral probiotic preparations on urinary supersaturation and oxalate excretion. Cross sectional studies in humans have studied the association of Oxalobacter formigenes colonization status and urinary oxalate excretion and prevalence of urinary stones. The intestinal microbiome of representative animals adapted to a high oxalate diet has been defined. RESULTS The fecal content of O. formigenes, the best studied oxalate-degrader, varies depending on stone status. However, trials with probiotics designed to degrade oxalate including those containing O. formigenes, Lactobacillus, and/or Bifidobacterium spp., have been disappointing. Multiple intestinal segments of animals on a high oxalate diet contains diverse communities of microorganisms that can function together to degrade and detoxify a large oxalate load. CONCLUSIONS Although the intestinal microbiome seems likely to play a role to modify gastrointestinal absorption of lithogenic substances and hence urinary stone risk, whether we can develop tools to manipulate it and decrease this kidney stone risk remains to be determined.
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Affiliation(s)
- John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
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19
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Sayer JA. Progress in Understanding the Genetics of Calcium-Containing Nephrolithiasis. J Am Soc Nephrol 2016; 28:748-759. [PMID: 27932479 DOI: 10.1681/asn.2016050576] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Renal stone disease is a frequent condition, causing a huge burden on health care systems globally. Calcium-based calculi account for around 75% of renal stone disease and the incidence of these calculi is increasing, suggesting environmental and dietary factors are acting upon a preexisting genetic background. The familial nature and significant heritability of stone disease is known, and recent genetic studies have successfully identified genes that may be involved in renal stone formation. The detection of monogenic causes of renal stone disease has been made more feasible by the use of high-throughput sequencing technologies and has also facilitated the discovery of novel monogenic causes of stone disease. However, the majority of calcium stone formers remain of undetermined genotype. Genome-wide association studies and candidate gene studies implicate a series of genes involved in renal tubular handling of lithogenic substrates, such as calcium, oxalate, and phosphate, and of inhibitors of crystallization, such as citrate and magnesium. Additionally, expression profiling of renal tissues from stone formers provides a novel way to explore disease pathways. New animal models to explore these recently-identified mechanisms and therapeutic interventions are being tested, which hopefully will provide translational insights to stop the growing incidence of nephrolithiasis.
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Affiliation(s)
- John A Sayer
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, United Kingdom
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Daudon M, Dessombz A, Frochot V, Letavernier E, Haymann JP, Jungers P, Bazin D. Comprehensive morpho-constitutional analysis of urinary stones improves etiological diagnosis and therapeutic strategy of nephrolithiasis. CR CHIM 2016. [DOI: 10.1016/j.crci.2016.05.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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USP2-45 Is a Circadian Clock Output Effector Regulating Calcium Absorption at the Post-Translational Level. PLoS One 2016; 11:e0145155. [PMID: 26756164 PMCID: PMC4710524 DOI: 10.1371/journal.pone.0145155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 12/01/2015] [Indexed: 01/06/2023] Open
Abstract
The mammalian circadian clock influences most aspects of physiology and behavior through the transcriptional control of a wide variety of genes, mostly in a tissue-specific manner. About 20 clock-controlled genes (CCGs) oscillate in virtually all mammalian tissues and are generally considered as core clock components. One of them is Ubiquitin-Specific Protease 2 (Usp2), whose status remains controversial, as it may be a cogwheel regulating the stability or activity of core cogwheels or an output effector. We report here that Usp2 is a clock output effector related to bodily Ca2+ homeostasis, a feature that is conserved across evolution. Drosophila with a whole-body knockdown of the orthologue of Usp2, CG14619 (dUsp2-kd), predominantly die during pupation but are rescued by dietary Ca2+ supplementation. Usp2-KO mice show hyperabsorption of dietary Ca2+ in small intestine, likely due to strong overexpression of the membrane scaffold protein NHERF4, a regulator of the Ca2+ channel TRPV6 mediating dietary Ca2+ uptake. In this tissue, USP2-45 is found in membrane fractions and negatively regulates NHERF4 protein abundance in a rhythmic manner at the protein level. In clock mutant animals (Cry1/Cry2-dKO), rhythmic USP2-45 expression is lost, as well as the one of NHERF4, confirming the inverse relationship between USP2-45 and NHERF4 protein levels. Finally, USP2-45 interacts in vitro with NHERF4 and endogenous Clathrin Heavy Chain. Taken together these data prompt us to define USP2-45 as the first clock output effector acting at the post-translational level at cell membranes and possibly regulating membrane permeability of Ca2+.
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22
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Cheungpasitporn W, Erickson SB, Rule AD, Enders F, Lieske JC. Short-Term Tolvaptan Increases Water Intake and Effectively Decreases Urinary Calcium Oxalate, Calcium Phosphate and Uric Acid Supersaturations. J Urol 2015; 195:1476-1481. [PMID: 26598423 DOI: 10.1016/j.juro.2015.11.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2015] [Indexed: 01/31/2023]
Abstract
PURPOSE Some patients cannot effectively increase water intake and urine volume to prevent urinary stones. Tolvaptan, a V2 receptor antagonist, blocks water reabsorption in the collecting duct and should decrease urinary supersaturation of stone forming solutes, although this action has never been proved. MATERIALS AND METHODS We conducted a double-blind, randomized, placebo controlled, crossover study of 21 calcium urinary stone formers stratified into majority calcium oxalate (10 patients) and calcium phosphate (11) groups. Patients received 45 mg tolvaptan per day or placebo for 1 week, followed by a washout week and crossover to tolvaptan or placebo for week 3. A 24-hour urine sample was collected at the end of weeks 1 and 3. RESULTS Tolvaptan vs placebo decreased urinary osmolality (mean ± SD 204 ± 96 vs 529 ± 213 mOsm/kg, p <0.001) and increased urinary volume (4.8 ± 2.9 vs 1.8 ± 0.9 L, p <0.001). The majority of urinary solute excretion rates, including sodium and calcium, did not change significantly, although oxalate secretion increased slightly (from mean ± SD 15 ± 8 to 23 ± 8 mg per 24 hours, p = 0.009). Mean ± SD urinary calcium oxalate supersaturation (-0.01 ± 1.14 vs 0.95 ± 0.87 dG, p <0.001), calcium phosphate supersaturation (-1.66 ± 1.17 vs -0.13 ± 1.02 dG, p <0.001) and uric acid supersaturation (-2.05 ± 4.05 vs -5.24 ± 3.12 dG, p = 0.04) all dramatically decreased. Effects did not differ between the calcium oxalate and calcium phosphate groups (p >0.05 for all interactions). CONCLUSIONS Tolvaptan increases urine volume and decreases urinary supersaturation in calcium stone formers. Further study is needed to determine if long-term use of V2 receptor antagonists results in fewer stone events.
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Affiliation(s)
| | - Stephen B Erickson
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Andrew D Rule
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
| | - Felicity Enders
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
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23
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Ketha H, Singh RJ, Grebe SK, Bergstralh EJ, Rule AD, Lieske JC, Kumar R. Altered Calcium and Vitamin D Homeostasis in First-Time Calcium Kidney Stone-Formers. PLoS One 2015; 10:e0137350. [PMID: 26332888 PMCID: PMC4558059 DOI: 10.1371/journal.pone.0137350] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/15/2015] [Indexed: 11/30/2022] Open
Abstract
Background Elevated serum 1,25-dihydroxyvitamin D (1,25(OH)2D) concentrations have been reported among cohorts of recurrent calcium (Ca) kidney stone-formers and implicated in the pathogenesis of hypercalciuria. Variations in Ca and vitamin D metabolism, and excretion of urinary solutes among first-time male and female Ca stone-formers in the community, however, have not been defined. Methods In a 4-year community-based study we measured serum Ca, phosphorus (P), 25-hydroxyvitamin D (25(OH)D), 1,25(OH)2D, 24,25-dihydroxyvitamin D (24,25(OH)2D), parathyroid hormone (PTH), and fibroblast growth factor-23 (FGF-23) concentrations in first-time Ca stone-formers and age- and gender frequency-matched controls. Results Serum Ca and 1,25(OH)2D were increased in Ca stone-formers compared to controls (P = 0.01 and P = 0.001). Stone-formers had a lower serum 24,25(OH)2D/25(OH)D ratio compared to controls (P = 0.008). Serum PTH and FGF-23 concentrations were similar in the groups. Urine Ca excretion was similar in the two groups (P = 0.82). In controls, positive associations between serum 25(OH)D and 24,25(OH)2D, FGF-23 and fractional phosphate excretion, and negative associations between serum Ca and PTH, and FGF-23 and 1,25(OH)2D were observed. In SF associations between FGF-23 and fractional phosphate excretion, and FGF-23 and 1,25(OH)2D, were not observed. 1,25(OH)2D concentrations associated more weakly with FGF-23 in SF compared with C (P <0.05). Conclusions Quantitative differences in serum Ca and 1,25(OH)2D and reductions in 24-hydroxylation of vitamin D metabolites are present in first-time SF and might contribute to first-time stone risk.
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Affiliation(s)
- Hemamalini Ketha
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ravinder J. Singh
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Stefan K. Grebe
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Eric J. Bergstralh
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andrew D. Rule
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - John C. Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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24
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The Wnt11 Signaling Pathway in Potential Cellular EMT and Osteochondral Differentiation Progression in Nephrolithiasis Formation. Int J Mol Sci 2015; 16:16313-29. [PMID: 26193266 PMCID: PMC4519952 DOI: 10.3390/ijms160716313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/22/2015] [Accepted: 07/07/2015] [Indexed: 11/17/2022] Open
Abstract
The molecular events leading to nephrolithiasis are extremely complex. Previous studies demonstrated that calcium and transforming growth factor-β1 (TGF-β1) may participate in the pathogenesis of stone formation, but the explicit mechanism has not been defined. Using a self-created genetic hypercalciuric stone-forming (GHS) rat model, we observed that the increased level of serous/uric TGF-β1 and elevated intracellular calcium in primary renal tubular epithelial cells (PRECs) was associated with nephrolithiasis progression in vivo. In the setting of high calcium plus high TGF-β1 in vitro, PRECs showed great potential epithelial to mesenchymal transition (EMT) progression and osteochondral differentiation properties, representing the multifarious increased mesenchymal and osteochondral phenotypes (Zeb1, Snail1, Col2A1, OPN, Sox9, Runx2) and decreased epithelial phenotypes (E-cadherin, CK19) bythe detection of mRNAs and corresponding proteins. Moreover, TGF-β-dependent Wnt11 knockdown and L-type Ca2+ channel blocker could greatly reverse EMT progression and osteochondral differentiation in PRECs. TGF-β1 alone could effectively promote EMT, but it had no effect on osteochondral differentiation in NRK cells (Rat kidney epithelial cell line). Stimulation with Ca2+ alone did not accelerate differentiation of NRK. Co-incubation of extracellular Ca2+ and TGF-β1 synergistically promotes EMT and osteochondral differentiation in NRK control cells. Our data supplied a novel view that the pathogenesis of calcium stone development may be associated with synergic effects of TGF-β1 and Ca2+, which promote EMT and osteochondral differentiation via Wnt11 and the L-type calcium channel.
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25
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Frick KK, Krieger NS, Bushinsky DA. Modeling hypercalciuria in the genetic hypercalciuric stone-forming rat. Curr Opin Nephrol Hypertens 2015; 24:336-44. [PMID: 26050120 PMCID: PMC4495578 DOI: 10.1097/mnh.0000000000000130] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW In this review, we discuss how the genetic hypercalciuric stone-forming (GHS) rats, which closely model idiopathic hypercalciuria and stone formation in humans, provide insights into the pathophysiology and consequences of clinical hypercalciuria. RECENT FINDINGS Hypercalciuria in the GHS rats is due to a systemic dysregulation of calcium transport, as manifest by increased intestinal calcium absorption, increased bone resorption and decreased renal tubule calcium reabsorption. Increased levels of vitamin D receptor in intestine, bone and kidney appear to mediate these changes. The excess receptors are biologically active and increase tissue sensitivity to exogenous vitamin D. Bones of GHS rats have decreased bone mineral density (BMD) as compared with Sprague-Dawley rats, and exogenous 1,25(OH)2D3 exacerbates the loss of BMD. Thiazide diuretics improve the BMD in GHS rats. SUMMARY Studying GHS rats allows direct investigation of the effects of alterations in diet and utilization of pharmacologic therapy on hypercalciuria, urine supersaturation, stone formation and bone quality in ways that are not possible in humans.
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Affiliation(s)
- Kevin K Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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26
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Krieger NS, Asplin JR, Frick KK, Granja I, Culbertson CD, Ng A, Grynpas MD, Bushinsky DA. Effect of Potassium Citrate on Calcium Phosphate Stones in a Model of Hypercalciuria. J Am Soc Nephrol 2015; 26:3001-8. [PMID: 25855777 DOI: 10.1681/asn.2014121223] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/02/2015] [Indexed: 01/24/2023] Open
Abstract
Potassium citrate is prescribed to decrease stone recurrence in patients with calcium nephrolithiasis. Citrate binds intestinal and urine calcium and increases urine pH. Citrate, metabolized to bicarbonate, should decrease calcium excretion by reducing bone resorption and increasing renal calcium reabsorption. However, citrate binding to intestinal calcium may increase absorption and renal excretion of both phosphate and oxalate. Thus, the effect of potassium citrate on urine calcium oxalate and calcium phosphate supersaturation and stone formation is complex and difficult to predict. To study the effects of potassium citrate on urine supersaturation and stone formation, we utilized 95th-generation inbred genetic hypercalciuric stone-forming rats. Rats were fed a fixed amount of a normal calcium (1.2%) diet supplemented with potassium citrate or potassium chloride (each 4 mmol/d) for 18 weeks. Urine was collected at 6, 12, and 18 weeks. At 18 weeks, stone formation was visualized by radiography. Urine citrate, phosphate, oxalate, and pH levels were higher and urine calcium level was lower in rats fed potassium citrate. Furthermore, calcium oxalate and calcium phosphate supersaturation were higher with potassium citrate; however, uric acid supersaturation was lower. Both groups had similar numbers of exclusively calcium phosphate stones. Thus, potassium citrate effectively raises urine citrate levels and lowers urine calcium levels; however, the increases in urine pH, oxalate, and phosphate levels lead to increased calcium oxalate and calcium phosphate supersaturation. Potassium citrate induces complex changes in urine chemistries and resultant supersaturation, which may not be beneficial in preventing calcium phosphate stone formation.
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Affiliation(s)
- Nancy S Krieger
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York;
| | - John R Asplin
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois; and
| | - Kevin K Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Ignacio Granja
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, Illinois; and
| | - Christopher D Culbertson
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Adeline Ng
- Laboratory Medicine and Pathobiology Department, University of Toronto, Toronto, Ontario, Canada
| | - Marc D Grynpas
- Laboratory Medicine and Pathobiology Department, University of Toronto, Toronto, Ontario, Canada
| | - David A Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
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Ng AH, Frick KK, Krieger NS, Asplin JR, Cohen-McFarlane M, Culbertson CD, Kyker-Snowman K, Grynpas MD, Bushinsky DA. 1,25(OH)₂D₃ induces a mineralization defect and loss of bone mineral density in genetic hypercalciuric stone-forming rats. Calcif Tissue Int 2014; 94:531-43. [PMID: 24481706 PMCID: PMC4276134 DOI: 10.1007/s00223-014-9838-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/07/2014] [Indexed: 11/29/2022]
Abstract
Genetic hypercalciuric stone-forming (GHS) rats, bred to maximize urine (u) calcium (Ca) excretion, demonstrate increased intestinal Ca absorption, increased bone Ca resorption, and reduced renal Ca reabsorption, all leading to elevated uCa compared to the parental Sprague-Dawley (SD) rats. GHS rats have increased numbers of vitamin D receptors (VDRs) at each site, with normal levels of 1,25(OH)₂D₃ (1,25D), suggesting their VDR is undersaturated with 1,25D. We have shown that 1,25D induces a greater increase in uCa in GHS than SD rats. To examine the effect of the increased VDR on the osseous response to 1,25D, we fed GHS and SD rats an ample Ca diet and injected either 1,25D [low dose (LD) 12.5 or high dose (HD) 25 ng/100 g body weight/day] or vehicle (veh) daily for 16 days. Femoral areal bone mineral density (aBMD, by DEXA) was decreased in GHS+LD and GHS+HD relative to GHS+veh, while there was no effect on SD. Vertebral aBMD was lower in GHS compared to SD and further decreased in GHS+HD. Both femoral and L6 vertebral volumetric BMD (by μCT) were lower in GHS and further reduced by HD. Histomorphometry indicated a decreased osteoclast number in GHS+HD compared to GHS+veh or SD+HD. In tibiae, GHS+HD trabecular thickness and number increased, with a 12-fold increase in osteoid volume but only a threefold increase in bone volume. Bone formation rate was decreased in GHS+HD relative to GHS+veh, confirming the mineralization defect. The loss of BMD and the mineralization defect in GHS rats contribute to increased hypercalciuria; if these effects persist, they would result in decreased bone strength, making these bones more fracture-prone. The enhanced effect of 1,25D in GHS rats indicates that the increased VDRs are biologically active.
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Affiliation(s)
- Adeline H. Ng
- Samuel Lunenfeld Research Institute, Toronto, Ontario, Canada
| | - Kevin K. Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Nancy S. Krieger
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | | | | | - Christopher D. Culbertson
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Kelly Kyker-Snowman
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Marc D. Grynpas
- Samuel Lunenfeld Research Institute, Toronto, Ontario, Canada
| | - David A. Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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Does crystal deposition in genetic hypercalciuric rat kidney tissue share similarities with bone formation? Urology 2014; 83:509.e7-14. [PMID: 24468523 DOI: 10.1016/j.urology.2013.11.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 10/20/2013] [Accepted: 11/04/2013] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To address the effect of bone-related factors and 1,25(OH)2D3/vitamin D receptor (VDR) on renal stone formation in idiopathic hypercalciuria using genetic hypercalciuric rats. METHODS The basal levels of bone-related factors were detected in Sprague-Dawley and genetic hypercalciuric rats. In VDR silenced kidneys, the expression levels of bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (Runx2), Osterix, and osteopontin (OPN) were measured, respectively. Tubular calcium phosphate deposits in kidneys and renal tubular epithelial cells (RTECs) were assessed using von Kossa stain. Kidneys were stained with immunohistochemical staining for OPN expression. Gene and protein expression levels of BMP2, Runx2, and Osterix were examined in RTECs incubated with 1,25(OH)2D3. RESULTS The basal levels of BMP2, Runx2, Osterix, and OPN were significantly increased in genetic hypercalciuric rats, whereas there were no differences in the expression levels of msh homeobox homolog 2 and alkaline phosphatase between the genetic hypercalciuric and normal control rats. VDR knockdown in genetic hypercalciuric rats reduced the expression levels of BMP2, Runx2, Osterix, and OPN. Tubular calcium phosphate deposits were also decreased in VDR silenced kidneys. Immunohistochemical staining showed that there was a reduction in OPN expression in RTECs along with reduction in calcification. Gene and protein expression levels of BMP2, Runx2, and Osterix were upregulated in RTECs incubated with 1,25(OH)2D3. The calcium phosphate deposits in RTECs were also increased by elevated 1,25(OH)2D3. CONCLUSION Our findings indicate that BMP2, Runx2, Osterix, and OPN might play an important role in renal stone formation in idiopathic hypercalciuria, and 1,25(OH)2D3/VDR might be the significant regulator in this process.
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29
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Frick KK, Asplin JR, Culbertson CD, Granja I, Krieger NS, Bushinsky DA. Persistence of 1,25D-induced hypercalciuria in alendronate-treated genetic hypercalciuric stone-forming rats fed a low-calcium diet. Am J Physiol Renal Physiol 2014; 306:F1081-7. [PMID: 24573387 DOI: 10.1152/ajprenal.00680.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Genetic hypercalciuric stone-forming (GHS) rats demonstrate increased intestinal Ca absorption, increased bone resorption, and reduced renal tubular Ca reabsorption leading to hypercalciuria and all form kidney stones. GHS have increased vitamin D receptors (VDR) at these sites of Ca transport. Injection of 1,25(OH)2D3 (1,25D) leads to a greater increase in urine (u)Ca in GHS than in control Sprague-Dawley (SD), possibly due to the additional VDR. In GHS the increased uCa persists on a low-Ca diet (LCD) suggesting enhanced bone resorption. We tested the hypothesis that LCD, coupled to inhibition of bone resorption by alendronate (alen), would eliminate the enhanced 1,25D-induced hypercalciuria in GHS. SD and GHS were fed LCD and half were injected daily with 1,25D. After 8 days all were also given alen until euthanasia at day 16. At 8 days, 1,25D increased uCa in SD and to a greater extent in GHS. At 16 days, alen eliminated the 1,25D-induced increase in uCa in SD. However, in GHS alen decreased, but did not eliminate, the 1,25D-induced hypercalciuria, suggesting maximal alen cannot completely prevent the 1,25D-induced bone resorption in GHS, perhaps due to increased VDR. There was no consistent effect on mRNA expression of renal transcellular or paracellular Ca transporters. Urine CaP and CaOx supersaturation (SS) increased with 1,25D alone in both SD and GHS. Alen eliminated the increase in CaP SS in SD but not in GHS. If these results are confirmed in humans with IH, the use of bisphosphonates, such as alen, may not prevent the decreased bone density observed in these patients.
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Affiliation(s)
- Kevin K Frick
- Research Assistant Professor of Medicine, Univ. of Rochester School of Medicine and Dentistry, Division of Nephrology, Dept. of Medicine, 601 Elmwood Ave., Box 675, Rochester, NY 14642.
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Moran ME. Modern Stone Science. Urolithiasis 2014. [DOI: 10.1007/978-1-4614-8196-6_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Toka HR, Genovese G, Mount DB, Pollak MR, Curhan GC. Frequency of rare allelic variation in candidate genes among individuals with low and high urinary calcium excretion. PLoS One 2013; 8:e71885. [PMID: 23991001 PMCID: PMC3753300 DOI: 10.1371/journal.pone.0071885] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 07/10/2013] [Indexed: 12/29/2022] Open
Abstract
Our study investigated the association of rare allelic variants with extremes of 24-hour urinary calcium excretion because higher urinary calcium excretion is a dominant risk factor for calcium-based kidney stone formation. We resequenced 40 candidate genes potentially related to urinary calcium excretion in individuals from the Nurses' Health Studies I & II and the Health Professionals Follow-up Study. A total of 960 participants were selected based on availability of 24-hour urine collection data and level of urinary calcium excretion (low vs. high). We utilized DNA sample pooling, droplet-based target gene enrichment, multiplexing, and high-throughput sequencing. Approximately 64% of samples (n = 615) showed both successful target enrichment and sequencing data with >20-fold deep coverage. A total of 259 novel allelic variants were identified. None of the rare gene variants (allele frequencies <2%) were found with increased frequency in the low vs. high urinary calcium groups; most of these variants were only observed in single individuals. Unadjusted analysis of variants with allele frequencies ≥ 2% suggested an association of the Claudin14 SNP rs113831133 with lower urinary calcium excretion (6/520 versus 29/710 haplotypes, P value = 0.003). Our data, together with previous human and animal studies, suggest a possible role for Claudin14 in urinary calcium excretion. Genetic validation studies in larger sample sets will be necessary to confirm our findings for rs113831133. In the tested set of candidate genes, rare allelic variants do not appear to contribute significantly to differences in urinary calcium excretion between individuals.
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Affiliation(s)
- Hakan R. Toka
- Division of Nephrology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Giulio Genovese
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David B. Mount
- Division of Nephrology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Martin R. Pollak
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gary C. Curhan
- Division of Nephrology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Channing Division of Network Medicine, Boston, Massachusetts, United States of America
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Frick KK, Asplin JR, Krieger NS, Culbertson CD, Asplin DM, Bushinsky DA. 1,25(OH)₂D₃-enhanced hypercalciuria in genetic hypercalciuric stone-forming rats fed a low-calcium diet. Am J Physiol Renal Physiol 2013; 305:F1132-8. [PMID: 23926184 DOI: 10.1152/ajprenal.00296.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The inbred genetic hypercalciuric stone-forming (GHS) rats exhibit many features of human idiopathic hypercalciuria and have elevated levels of vitamin D receptors (VDR) in calcium (Ca)-transporting organs. On a normal-Ca diet, 1,25(OH)2D3 (1,25D) increases urine (U) Ca to a greater extent in GHS than in controls [Sprague-Dawley (SD)]. The additional UCa may result from an increase in intestinal Ca absorption and/or bone resorption. To determine the source, we asked whether 1,25D would increase UCa in GHS fed a low-Ca (0.02%) diet (LCD). With 1,25D, UCa in SD increased from 1.2 ± 0.1 to 9.3 ± 0.9 mg/day and increased more in GHS from 4.7 ± 0.3 to 21.5 ± 0.9 mg/day (P < 0.001). In GHS rats on LCD with or without 1,25D, UCa far exceeded daily Ca intake (2.6 mg/day). While the greater excess in UCa in GHS rats must be derived from bone mineral, there may also be a 1,25D-mediated decrease in renal tubular Ca reabsorption. RNA expression of the components of renal Ca transport indicated that 1,25D administration results in a suppression of klotho, an activator of the renal Ca reabsorption channel TRPV5, in both SD and GHS rats. This fall in klotho would decrease tubular reabsorption of the 1,25D-induced bone Ca release. Thus, the greater increase in UCa with 1,25D in GHS fed LCD strongly suggests that the additional UCa results from an increase in bone resorption, likely due to the increased number of VDR in the GHS rat bone cells, with a possible component of decreased renal tubular calcium reabsorption.
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Affiliation(s)
- Kevin K Frick
- Univ. of Rochester School of Medicine and Dentistry, Div. of Nephrology, Dept. of Medicine, 601 Elmwood Ave., Box 675, Rochester, NY 14642.
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Loh NY, Bentley L, Dimke H, Verkaart S, Tammaro P, Gorvin CM, Stechman MJ, Ahmad BN, Hannan FM, Piret SE, Evans H, Bellantuono I, Hough TA, Fraser WD, Hoenderop JGJ, Ashcroft FM, Brown SDM, Bindels RJM, Cox RD, Thakker RV. Autosomal dominant hypercalciuria in a mouse model due to a mutation of the epithelial calcium channel, TRPV5. PLoS One 2013; 8:e55412. [PMID: 23383183 PMCID: PMC3559602 DOI: 10.1371/journal.pone.0055412] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 12/22/2012] [Indexed: 12/05/2022] Open
Abstract
Hypercalciuria is a major cause of nephrolithiasis, and is a common and complex disorder involving genetic and environmental factors. Identification of genetic factors for monogenic forms of hypercalciuria is hampered by the limited availability of large families, and to facilitate such studies, we screened for hypercalciuria in mice from an N-ethyl-N-nitrosourea mutagenesis programme. We identified a mouse with autosomal dominant hypercalciuria (HCALC1). Linkage studies mapped the Hcalc1 locus to a 11.94 Mb region on chromosome 6 containing the transient receptor potential cation channel, subfamily V, members 5 (Trpv5) and 6 (Trpv6) genes. DNA sequence analysis of coding regions, intron-exon boundaries and promoters of Trpv5 and Trpv6 identified a novel T to C transition in codon 682 of TRPV5, mutating a conserved serine to a proline (S682P). Compared to wild-type littermates, heterozygous (Trpv5682P/+) and homozygous (Trpv5682P/682P) mutant mice had hypercalciuria, polyuria, hyperphosphaturia and a more acidic urine, and ∼10% of males developed tubulointerstitial nephritis. Trpv5682P/682P mice also had normal plasma parathyroid hormone but increased 1,25-dihydroxyvitamin D3 concentrations without increased bone resorption, consistent with a renal defect for the hypercalciuria. Expression of the S682P mutation in human embryonic kidney cells revealed that TRPV5-S682P-expressing cells had a lower baseline intracellular calcium concentration than wild-type TRPV5-expressing cells, suggesting an altered calcium permeability. Immunohistological studies revealed a selective decrease in TRPV5-expression from the renal distal convoluted tubules of Trpv5682P/+ and Trpv5682P/682P mice consistent with a trafficking defect. In addition, Trpv5682P/682P mice had a reduction in renal expression of the intracellular calcium-binding protein, calbindin-D28K, consistent with a specific defect in TRPV5-mediated renal calcium reabsorption. Thus, our findings indicate that the TRPV5 S682P mutant is functionally significant and study of HCALC1, a novel model for autosomal dominant hypercalciuria, may help further our understanding of renal calcium reabsorption and hypercalciuria.
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Affiliation(s)
- Nellie Y. Loh
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Liz Bentley
- MRC Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council, Harwell, Oxfordshire, United Kingdom
| | - Henrik Dimke
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Sjoerd Verkaart
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Paolo Tammaro
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Caroline M. Gorvin
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Michael J. Stechman
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Bushra N. Ahmad
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Fadil M. Hannan
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Sian E. Piret
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
| | - Holly Evans
- Academic Unit of Bone Biology, University of Sheffield, The Medical School, Sheffield, United Kingdom
| | - Ilaria Bellantuono
- Academic Unit of Bone Biology, University of Sheffield, The Medical School, Sheffield, United Kingdom
| | - Tertius A. Hough
- MRC Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council, Harwell, Oxfordshire, United Kingdom
| | - William D. Fraser
- Faculty of Medical and Health Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Joost G. J. Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Frances M. Ashcroft
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Steve D. M. Brown
- MRC Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council, Harwell, Oxfordshire, United Kingdom
| | - René J. M. Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Roger D. Cox
- MRC Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council, Harwell, Oxfordshire, United Kingdom
| | - Rajesh V. Thakker
- Academic Endocrine Unit, Nuffield Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Headington, Oxford, United Kingdom
- * E-mail:
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Frick KK, Asplin JR, Favus MJ, Culbertson C, Krieger NS, Bushinsky DA. Increased biological response to 1,25(OH)(2)D(3) in genetic hypercalciuric stone-forming rats. Am J Physiol Renal Physiol 2013; 304:F718-26. [PMID: 23344574 DOI: 10.1152/ajprenal.00645.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Genetic hypercalciuric stone-forming (GHS) rats, bred to maximize urine (U) calcium (Ca) excretion, have increased intestinal Ca absorption and bone Ca resorption and reduced renal Ca reabsorption, leading to increased UCa compared with the Sprague-Dawley (SD) rats. GHS rats have increased vitamin D receptors (VDR) at each of these sites, with normal levels of 1,25(OH)(2)D(3) (1,25D), indicating that their VDR is undersaturated with 1,25D. We tested the hypothesis that 1,25D would induce a greater increase in UCa in GHS rats by feeding both strains ample Ca and injecting 1,25D (25 ng · 100 g body wt(-1) · day(-1)) or vehicle for 16 days. With 1,25D, UCa in SD increased from 1.7 ± 0.3 mg/day to 24.4 ± 1.2 (Δ = 22.4 ± 1.5) and increased more in GHS from 10.5 ± 0.7 to 41.9 ± 0.7 (Δ = 29.8 ± 1.8; P = 0.003). To determine the mechanism of the greater increase in UCa in GHS rats, we measured kidney RNA expression of components of renal Ca transport. Expression of transient receptor potential vanilloid (TRPV)5 and calbindin D(28K) were increased similarly in SD + 1,25D and GHS + 1,25D. The Na(+)/Ca(2+) exchanger (NCX1) was increased in GHS + 1,25D. Klotho was decreased in SD + 1,25D and GHS + 1,25D. TRPV6 was increased in SD + 1,25D and increased further in GHS + 1,25D. Claudin 14, 16, and 19, Na/K/2Cl transporter (NKCC2), and secretory K channel (ROMK) did not differ between SD + 1,25D and GHS + 1,25D. Increased UCa with 1,25D in GHS exceeded that of SD, indicating that the increased VDR in GHS induces a greater biological response. This increase in UCa, which must come from the intestine and/or bone, must exceed any effect of 1,25D on TRPV6 or NCX1-mediated renal Ca reabsorption.
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Affiliation(s)
- Kevin K Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Perry GML, Nehrke KW, Bushinsky DA, Reid R, Lewandowski KL, Hueber P, Scheinman SJ. Sex modifies genetic effects on residual variance in urinary calcium excretion in rat (Rattus norvegicus). Genetics 2012; 191:1003-13. [PMID: 22554889 PMCID: PMC3389963 DOI: 10.1534/genetics.112.138909] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/23/2012] [Indexed: 01/03/2023] Open
Abstract
Conventional genetics assumes common variance among alleles or genetic groups. However, evidence from vertebrate and invertebrate models suggests that residual genotypic variance may itself be under partial genetic control. Such a phenomenon would have great significance: high-variability alleles might confound the detection of "classically" acting genes or scatter predicted evolutionary outcomes among unpredicted trajectories. Of the few works on this phenomenon, many implicate sex in some aspect of its control. We found that female genetic hypercalciuric stone-forming (GHS) rats (Rattus norvegicus) had higher coefficients of variation (CVs) for urinary calcium (CV = 0.14) than GHS males (CV = 0.06), and the reverse in normocalciuric Wistar-Kyoto rats (WKY) (CV(♂) = 0.14; CV(♀) = 0.09), suggesting sex-by-genotype interaction on residual variance. We therefore investigated the effect of sex on absolute-transformed residuals in urinary calcium in an F(2) GHS × WKY mapping cohort. Absolute residuals were associated with genotype at two microsatellites, D3Rat46 (RNO3, 33.9 Mb) and D4Mgh1 (RNO4, 84.8 MB) at Bonferroni thresholds across the entire cohort, and with the microsatellites D3Rat46, D9Mgh2 (RNO9, 84.4 Mb), and D12Rat25 (RNO12, 40.4 Mb) in females (P < 0.05) but not males. In GHS chromosome 1 congenic lines bred onto a WKY genomic background, we found that congenic males had significantly (P < 0.0001) higher CVs for urinary calcium (CV = 0.25) than females (CV = 0.15), supporting the hypothesis of the inheritance of sex-by-genotype interaction on this effect. Our findings suggest that genetic effects on residual variance are sex linked; heritable, sex-specific residuals might have great potential implications for evolution, adaptation, and genetic analysis.
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Affiliation(s)
- Guy M L Perry
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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Nephrolithiasis and Its Interrelationship with Vitamin D, Parathyroid Hormone, and Calcium. Urolithiasis 2012. [DOI: 10.1007/978-1-4471-4387-1_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ali A, Khan Q, Jafar TH. Kidney Stones and Chronic Kidney Disease. Urolithiasis 2012. [DOI: 10.1007/978-1-4471-4387-1_74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Xi QL, Wang SG, Ye ZQ, Zhu ZW, Li C, Bai J, Yu X, Liu JH. Effect of Silencing VDR Gene in Kidney on Renal Epithelial Calcium Transporter Proteins and Urinary Calcium Excretion in Genetic Hypercalciuric Stone-forming Rats. Urology 2011; 78:1442.e1-7. [DOI: 10.1016/j.urology.2011.08.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/26/2011] [Accepted: 08/26/2011] [Indexed: 11/25/2022]
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Abstract
Nephrolithiasis is a prevalent and costly condition with high recurrence rate. A medical evaluation to identify abnormalities responsible for nephrolithiasis and guide subsequent therapy has been advocated to reduce the risk of stone recurrence. The evaluation of kidney stone formers generally comprises an extensive medical history to identify metabolic, environmental, dietary and/or genetic factors contributing to stone formation. Imaging studies are utilized to evaluate and follow stone burden. Laboratory studies including stone composition analysis and serum and urinary chemistries are commonly obtained to further assess for any underlying systemic disorders, to detect environmental and metabolic processes contributing to stone disease, and to guide initial and follow-up dietary and pharmacological therapy. The nature and extent of such an evaluation is discussed in this review article.
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Affiliation(s)
- Naim Maalouf
- Department of Internal Medicine and Charles and Jane Pak Center for Mineral Metabolism, University of Texas Southwestern Medical Center Dallas, TX, U.S.A
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Oh SY, Kwon JK, Lee SY, Ha MS, Kwon YW, Moon YT. A comparative study of experimental rat models of renal calcium oxalate stone formation. J Endourol 2011; 25:1057-61. [PMID: 21568694 DOI: 10.1089/end.2010.0386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this study was to design a simple and convenient rat model with significant calcium oxalate crystal deposition in the kidney. MATERIALS AND METHODS Sprague-Dawley rats were divided into seven groups of 30 rats each. One group of rats was untreated to serve as controls. Two of the groups of rats were provided with drinking water supplemented with 1% ethylene glycol (EG), and of these two groups, one group was also administered vitamin D. Two groups of rats received intraperitoneal injections of EG, and of these two groups, one group also received vitamin D. Two groups of rats received intraperitoneal injections of glyoxylate, and of these two groups, one group also received vitamin D. We analyzed 24-hour urine samples for urinary constituents for all experimental groups, including calcium, oxalate, citrate, uric acid, pH, and urine volume. The kidneys were examined for crystal deposition using histologic examination and for osteopontin expression using immunohistochemical staining. RESULTS Calcium-oxalate crystals were found in all rats injected with glyoxylate after 1 week. The degree of crystal deposition in rats injected with glyoxylate for 1 week was significantly increased compared with rats fed EG for 4 weeks. CONCLUSIONS Intraperitoneal injection of glyoxylate is a faster, more exact, and more reliable method to produce calcium oxalate crystal deposition in the kidney than previous urolithiasis animal models.
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Affiliation(s)
- Seung Young Oh
- Department of Urology, Hyundae Hospital, Namyangju, Korea
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Attanasio M. The genetic components of idiopathic nephrolithiasis. Pediatr Nephrol 2011; 26:337-46. [PMID: 20563734 DOI: 10.1007/s00467-010-1562-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 05/03/2010] [Accepted: 05/07/2010] [Indexed: 02/04/2023]
Abstract
Nephrolithiasis is a cause of significant morbidity and medical care expenses worldwide. Its prevalence has increased steadily during the last three decades among both adults and children. This trend suggests that changing environmental factors play a significant role in the risk of developing kidney stones although, conversely, there are many indications that genes play an important role in this condition as well. A limited number of monogenic forms have been identified, but the majority of nephrolithiasis cases are the result of complex, multi-factorial interactions between genetic inheritance and environmental exposure. Scientific evidence indicates that inheritance accounts for about half of the risk of common forms, making these forms suitable for investigation by genetic analysis. Here, we review the numerous studies that have been conducted to establish the role of genes in determining the risk of nephrolithiasis, the differential contribution of genes to this risk, and the confounding influence that environmental variables have on genetic studies.
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Affiliation(s)
- Massimo Attanasio
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, G5.100, Dallas, TX 75390, USA.
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Experimentally induced hyperoxaluria in MCP-1 null mice. ACTA ACUST UNITED AC 2010; 39:253-8. [PMID: 21161647 DOI: 10.1007/s00240-010-0345-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 11/08/2010] [Indexed: 10/18/2022]
Abstract
Experimental animal model studies suggest that calcium oxalate (CaOx) crystal deposition in the kidneys is associated with the development of oxidative stress, epithelial injury and inflammation. There is increased production of inflammatory molecules including osteopontin (OPN), monocyte chemoattractant protein-1 (MCP-1) and various subunits of inter-alpha-inhibitor such as bikunin. What does the increased production of such molecules suggest? Is it a cause or consequence of crystal deposition? We hypothesized that over-expression and increased production of MCP-1 is a result of the interaction between renal epithelial cells and CaOx crystals after their deposition in the renal tubules. We induced hyperoxaluria in MCP-1 null as well as wild type mice and examined pathological changes in their kidneys and urine. Both wild type and MCP-1 null male mice became hyperoxaluric and demonstrated CaOx crystalluria. Neither of them developed crystal deposits in their kidneys. Both showed some morphological changes in their renal proximal tubules. Significant pathological changes such as cell death and increased urinary excretion of LDH were not seen. Results suggest that at least in mice (1) Increase in oxalate and decrease in citrate excretion can lead to CaOx crystalluria but not CaOx nephrolithiasis; (2) MCP-1 does not play a role in crystal retention within the kidneys; (3) Expression of OPN and MCP-1 is not increased in the kidneys in the absence of crystal deposition; (4) Crystal deposition is necessary for significant pathological changes and movement of monocytes and macrophages into the interstitium.
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Gögebakan B, Igci YZ, Arslan A, Igci M, Erturhan S, Oztuzcu S, Sen H, Demiryürek S, Arikoglu H, Cengiz B, Bayraktar R, Yurtseven C, Sarıca K, Demiryürek AT. Association Between the T-593A and C6982T Polymorphisms of the Osteopontin Gene and Risk of Developing Nephrolithiasis. Arch Med Res 2010; 41:442-8. [DOI: 10.1016/j.arcmed.2010.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/25/2010] [Indexed: 10/18/2022]
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Khan SR, Glenton PA. Experimental induction of calcium oxalate nephrolithiasis in mice. J Urol 2010; 184:1189-96. [PMID: 20663521 DOI: 10.1016/j.juro.2010.04.065] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Indexed: 02/08/2023]
Abstract
PURPOSE The availability of various transgenic and knockout mice provides an excellent opportunity to better understand the pathophysiology of calcium oxalate stone disease. However, attempts to produce calcium oxalate nephrolithiasis in mice have not been successful. We hypothesized that calcium oxalate nephrolithiasis in mice requires increasing urine calcium and oxalate excretion, and experimentally induced hyperoxaluria alone is not sufficient. To provide evidence we induced hyperoxaluria by administering hyperoxaluria inducing agents in normocalciuric and hypercalciuric mice, and investigating various aspects of nephrolithiasis. MATERIALS AND METHODS We administered ethylene glycol, glyoxylate or hydroxyl proline via diet in male and female normocalciuric B6 mice, and in hypercalciuric sodium phosphate co-transporter type 2 a -/- mice for 4 weeks. We collected 24-hour urine samples on days 0, 3, 7, 14, 21 and 28, and analyzed them for pH, creatinine, lactate dehydrogenase calcium and oxalate. Kidneys were examined using light microscopy. Urine was examined for crystals using light and scanning electron microscopy. RESULTS Hypercalciuric mice on hydroxyl proline did not tolerate treatment and were sacrificed before 28 days. All mice on ethylene glycol, glyoxylate or hydroxyl proline became hyperoxaluric and showed calcium oxalate crystalluria. No female, normocalciuric or hypercalciuric mice showed renal calcium oxalate crystal deposits. Calcium oxalate nephrolithiasis developed in all mice on glyoxylate and in some on ethylene glycol. In all mice the kidneys showed epithelial injury. Male mice particularly on glyoxylate had more renal injury and inflammatory cell migration into the interstitium around the crystal deposits. CONCLUSIONS Results confirm that hyperoxaluria induction alone is not sufficient to create calcium oxalate nephrolithiasis in mice. Hypercalciuria is also required. Kidneys in male mice are more prone to injury than those in female mice and are susceptible to calcium oxalate crystal deposition. Perhaps epithelial injury promotes crystal retention. Thus, calcium oxalate nephrolithiasis in mice is gender dependent, and requires hypercalciuria and hyperoxaluria.
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Affiliation(s)
- Saeed R Khan
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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Igci M, Arslan A, Igci YZ, Gogebakan B, Erturhan MS, Cengiz B, Oztuzcu S, Cakmak EA, Demiryurek AT. Bikunin and α1-microglobulin/bikunin precursor (AMBP) gene mutational screening in patients with kidney stones: a case-control study. ACTA ACUST UNITED AC 2010; 44:413-9. [PMID: 20602574 DOI: 10.3109/00365599.2010.497768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Bikunin is an inhibitor of kidney stone formation synthesized in the liver together with α(1)-microglobulin from the α(1)-microglobulin/bikunin precursor (AMBP) gene. The aim of this study was to investigate the possible association between bikunin/AMBP gene polymorphisms and urinary stone formation. MATERIAL AND METHODS To analyse the DNA, blood samples were taken from 75 kidney stone formers who had a familial stone history, 35 sporadic stone formers and 101 healthy individuals. Four exons of bikunin gene and five parts of the promoter region of the AMBP gene were screened using single-strand conformation polymorphism and nucleotide sequence analysis. RESULTS The Init-2 region of the promoter of AMBP gene had polymorphisms at positions -218 and -189 nt giving three different genotypes having 1,3, 2,4 and 1,2,3,4 alleles with frequencies of 17.06%, 60.19% and 22.75%, respectively, in all groups. Therefore, the Init-2 region appears to be polymorphic. As a result, the 1,3 allele has -218G and -189T complying with the reference database sequence, the 2,4 allele has -218G and T-189C substitution and the allele 1,2,3,4 genotype has substitutions at positions G-218C and T-189C. CONCLUSIONS There were no significant differences in allele distribution between patients and controls. These common alleles exist in the Turkish population independent of stone formation. These results are the first to demonstrate the existence of bikunin and AMBP promoter polymorphism. Although the Init-2 region of the AMBP gene is the binding site for various transcription factors, the results showed no association between these observed genotypes and stone-forming phenotypes.
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Affiliation(s)
- Mehri Igci
- Department of Medical Biology, Faculty of Medicine, University of Gaziantep, Gaziantep, Turkey.
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Sas DJ, Hulsey TC, Shatat IF, Orak JK. Increasing incidence of kidney stones in children evaluated in the emergency department. J Pediatr 2010; 157:132-7. [PMID: 20362300 DOI: 10.1016/j.jpeds.2010.02.004] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/28/2009] [Accepted: 02/03/2010] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To test the hypothesis that there is an increase in the incidence of childhood nephrolithiasis in the state of South Carolina. STUDY DESIGN We analyzed demographic data from a statewide database on incidence of kidney stones from emergency department data and financial charges. Data were compared with population data from the US Census to control for population growth. RESULTS There was a significant increase in the incidence of kidney stones in children between 1996 and 2007. The greatest rate of increase was seen in adolescents, pre-adolescents, and Caucasian children. Infants, toddlers, and African-American children did not show significantly increased incidence in the period. Girls show a growing predominance in our population. The amount of money charged for care of children with kidney stones has gone up >4-fold in our state. CONCLUSION The incidence of kidney stone disease has risen dramatically in the state of South Carolina since 1996. Further studies investigating potential contributing factors are needed to prevent this costly and painful condition.
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Affiliation(s)
- David J Sas
- Division of Pediatric Nephrology, Medical University of South Carolina Children's Hospital, Charleston, SC 29425-6080, USA.
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Bai S, Wang H, Shen J, Zhou R, Bushinsky DA, Favus MJ. Elevated vitamin D receptor levels in genetic hypercalciuric stone-forming rats are associated with downregulation of Snail. J Bone Miner Res 2010; 25:830-40. [PMID: 19929616 PMCID: PMC3153334 DOI: 10.1359/jbmr.091010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 09/21/2009] [Accepted: 10/09/2009] [Indexed: 11/18/2022]
Abstract
Patients with idiopathic hypercalciuria (IH) and genetic hypercalciuric stone-forming (GHS) rats, an animal model of IH, are both characterized by normal serum Ca, hypercalciuria, Ca nephrolithiasis, reduced renal Ca reabsorption, and increased bone resorption. Serum 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels are elevated or normal in IH and are normal in GHS rats. In GHS rats, vitamin D receptor (VDR) protein levels are elevated in intestinal, kidney, and bone cells, and in IH, peripheral blood monocyte VDR levels are high. The high VDR is thought to amplify the target-tissue actions of normal circulating 1,25(OH)(2)D levels to increase Ca transport. The aim of this study was to elucidate the molecular mechanisms whereby Snail may contribute to the high VDR levels in GHS rats. In the study, Snail gene expression and protein levels were lower in GHS rat tissues and inversely correlated with VDR gene expression and protein levels in intestine and kidney cells. In human kidney and colon cell lines, ChIP assays revealed endogenous Snail binding close to specific E-box sequences within the human VDR promoter region, whereas only one E-box specifically bound Snail in the rat promoter. Snail binding to rat VDR promoter E-box regions was reduced in GHS compared with normal control intestine and was accompanied by hyperacetylation of histone H(3). These results provide evidence that elevated VDR in GHS rats likely occurs because of derepression resulting from reduced Snail binding to the VDR promoter and hyperacetylation of histone H(3).
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Affiliation(s)
- Shaochun Bai
- Section of Endocrinology and Metabolism, The University of Chicago Pritzker School of MedicineChicago, IL, USA
| | - Hongwei Wang
- Section of Endocrinology and Metabolism, The University of Chicago Pritzker School of MedicineChicago, IL, USA
| | - Jikun Shen
- Section of Endocrinology and Metabolism, The University of Chicago Pritzker School of MedicineChicago, IL, USA
| | - Randal Zhou
- Section of Endocrinology and Metabolism, The University of Chicago Pritzker School of MedicineChicago, IL, USA
| | - David A Bushinsky
- Department of Medicine, University of Rochester School of MedicineRochester, New York, USA
| | - Murray J Favus
- Section of Endocrinology and Metabolism, The University of Chicago Pritzker School of MedicineChicago, IL, USA
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Ha YS, Tchey DU, Kang HW, Kim YJ, Yun SJ, Lee SC, Kim WJ. Phosphaturia as a promising predictor of recurrent stone formation in patients with urolithiasis. Korean J Urol 2010; 51:54-9. [PMID: 20414412 PMCID: PMC2855459 DOI: 10.4111/kju.2010.51.1.54] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 11/05/2009] [Indexed: 11/19/2022] Open
Abstract
Purpose Recent studies have suggested that renal phosphate leakage and the associated phosphaturia are significant underlying causes of calcium urolithiasis. The aims of this study were to assess whether phosphaturia relates to urinary metabolic abnormalities and recurrent stone formation. Materials and Methods A database of patient histories and urine chemistries was analyzed for 1,068 consecutive stone formers (SFs) and 106 normal controls. Urine values for phosphaturia that were higher than 95% of the normal control values were defined as indicating hyperphosphaturia, and the effect of phosphaturia on urinary metabolites and stone recurrence was determined. Of these patients, 247 patients (23.1%) who had been followed up for more than 36 months or had a recurrence of stones during follow-up (median, 46.0 months; range, 5-151) were included in the analyses for stone recurrence. Results Of the SFs, 19.9% (212/1,068) had increased urinary phosphate excretion. SFs with hyperphosphaturia had a greater urinary volume and higher levels of calcium, uric acid, oxalate, and citrate than did SFs with normophosphaturia. A multivariate Cox regression model, stratified by stone episodes, revealed that hyperphosphaturia was an independent predictor of recurrent stone formation in first-time SFs (hazard ratio [HR]: 2.122; 95% confidence interval [CI]: 1.100-4.097; p=0.025). No association was detected between hyperphosphaturia and recurrent stone formation in recurrent SFs. Kaplan-Meier curves showed identical results. Conclusions This study demonstrates that hyperphosphaturia is closely associated with urinary metabolic abnormalities. Furthermore, hyperphosphaturia is a significant risk factor for stone recurrence in first-time SFs.
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Affiliation(s)
- Yun-Sok Ha
- Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea
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Wiessner JH, Garrett MR, Roman RJ, Mandel NS. Dissecting the genetic basis of kidney tubule response to hyperoxaluria using chromosome substitution strains. Am J Physiol Renal Physiol 2009; 297:F301-6. [PMID: 19493966 DOI: 10.1152/ajprenal.00009.2009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whether genetics may play a role in the pathophysiologic response of kidney tubules to oxalate exposure remains unexplored despite that as many as 15% of the U.S. population annually will experience a kidney stone composed of calcium oxalate. To explore this issue, we utilized a panel of chromosome substitution strains in which one chromosome at a time was transferred from the Brown Norway (BN) rat onto the Dahl salt-sensitive (SS) genetic background. Hyperoxaluria was induced by adding hydroxyproline (HP) to the drinking water. A dose-response (0-2% HP) study found that both SS and BN exhibited the same level of oxalate excretion as HP concentration increased, but only the BN exhibited changes in urothelial pathology and demonstrated crystal deposition at sites of urothelial injury as a function of dose (at 1.5-2.0%). The consomic panel was treated with 2.0% HP and evaluated for hyperoxaluria, renal injury, and crystal deposition. Tubular injury (% Area) and crystal deposition (% Area) were similar between the resistant SS and SS-4, -6, -7, -8, -9, -11, -16, and -20(BN) consomic rats. However, tubular injury was significantly increased in SS-2(BN) compared with the SS parental (9.8 +/- 1.56 and 4.2 +/- 1.09%, respectively). Crystal deposition was observed in SS-2(BN) and SS-18(BN) (4.7 +/- 0.70 and 3.5 +/- 1.3%, respectively) to the same extent as seen in the susceptible BN (3.2 +/- 0.44%). The fact that crystal deposition was observed in SS-18(BN) without extensive overall tubule injury, compared with the more severe widespread tubular injury seen in SS-2(BN), suggests that the underlying mechanism of each locus is different. In conclusion, these studies establish that BN rats demonstrate oxalate-associated pathology and they retain calcium oxalate crystals coincident with urothelial injury but SS rats do not. These observations establish that BN rat chromosome 2 and 18 harbor genes that contribute to these processes.
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Affiliation(s)
- John H Wiessner
- Kidney Disease Center, Medical College of Wisconsin and Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin 53295, USA
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Renkema KY, Velic A, Dijkman HB, Verkaart S, van der Kemp AW, Nowik M, Timmermans K, Doucet A, Wagner CA, Bindels RJ, Hoenderop JG. The calcium-sensing receptor promotes urinary acidification to prevent nephrolithiasis. J Am Soc Nephrol 2009; 20:1705-13. [PMID: 19470676 DOI: 10.1681/asn.2008111195] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Hypercalciuria increases the risk for urolithiasis, but renal adaptive mechanisms reduce this risk. For example, transient receptor potential vanilloid 5 knockout (TPRV5(-/-)) mice lack kidney stones despite urinary calcium (Ca(2+)) wasting and hyperphosphaturia, perhaps as a result of their significant polyuria and urinary acidification. Here, we investigated the mechanisms linking hypercalciuria with these adaptive mechanisms. Exposure of dissected mouse outer medullary collecting ducts to high (5.0 mM) extracellular Ca(2+) stimulated H(+)-ATPase activity. In TRPV5(-/-) mice, activation of the renal Ca(2+)-sensing receptor promoted H(+)-ATPase-mediated H(+) excretion and downregulation of aquaporin 2, leading to urinary acidification and polyuria, respectively. Gene ablation of the collecting duct-specific B1 subunit of H(+)-ATPase in TRPV5(-/-) mice abolished the enhanced urinary acidification, which resulted in severe tubular precipitations of Ca(2+)-phosphate in the renal medulla. In conclusion, activation of Ca(2+)-sensing receptor by increased luminal Ca(2+) leads to urinary acidification and polyuria. These beneficial adaptations facilitate the excretion of large amounts of soluble Ca(2+), which is crucial to prevent the formation of kidney stones.
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Affiliation(s)
- Kirsten Y Renkema
- Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
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