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Protos AN, Jeyakumar AKC, Sams H, Dossabhoy NR, Tsiouris A. Coronary artery bypass surgery in a patient with Bartter's syndrome - postoperative critical care management: a case report. Indian J Thorac Cardiovasc Surg 2024; 40:357-360. [PMID: 38681720 PMCID: PMC11045673 DOI: 10.1007/s12055-023-01658-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 05/01/2024] Open
Abstract
Bartter syndrome is a rare, renal tubulopathy caused by defective salt reabsorption in the thick ascending limb of the loop of Henle which results in salt wasting, hypokalemia, and metabolic disturbances. The electrolyte disturbances associated with this condition can be difficult to manage in the postoperative setting, especially in patients undergoing cardiac surgery. We report a case of a 62-year-old male with a history of diabetes, hypertension, coronary artery disease, and Bartter syndrome who underwent coronary artery bypass grafting and who developed severe lactic acidemia and severe electrolyte abnormalities postoperatively. Treatment consisted of aggressive resuscitation with crystalloid and intravenous (IV) electrolyte replacement.
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Affiliation(s)
- Adam Nicholas Protos
- Division of Cardiac Surgery, Department of Surgery, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 USA
| | - Ashok Kumar Coimbatore Jeyakumar
- Division of Cardiac Surgery, Department of Surgery, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 USA
| | - Hanna Sams
- Division of Cardiac Surgery, Department of Surgery, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 USA
| | - Neville Rohinton Dossabhoy
- Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 USA
| | - Athanasios Tsiouris
- Division of Cardiac Surgery, Department of Surgery, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 USA
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Guo W, Ji P, Xie Y. Genetic diagnosis and treatment of hereditary renal tubular disease with hypokalemia and alkalosis. J Nephrol 2023; 36:575-591. [PMID: 35994232 DOI: 10.1007/s40620-022-01428-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022]
Abstract
Renal tubules play an important role in maintaining water, electrolyte, and acid-base balance. Renal tubule dysfunction can cause electrolyte disorders and acid-base imbalance. Clinically, hypokalemic renal tubular disease is the most common tubule disorder. With the development of molecular genetics and gene sequencing technology, hereditary renal tubular diseases have attracted attention, and an increasing number of pathogenic genes related to renal tubular diseases have been discovered and reported. Inherited renal tubular diseases mainly occur due to mutations in genes encoding various specific transporters or ion channels expressed on the tubular epithelial membrane, leading to dysfunctional renal tubular reabsorption, secretion, and excretion. An in-depth understanding of the molecular genetic basis of hereditary renal tubular disease will help to understand the physiological function of renal tubules, the mechanism by which the kidney maintains water, electrolyte, and acid-base balance, and the relationship between the kidney and other systems in the body. Meanwhile, understanding these diseases also improves our understanding of the pathogenesis of hypokalemia, alkalosis and other related diseases and ultimately promotes accurate diagnostics and effective disease treatment. The present review summarizes the most common hereditary renal tubular diseases (Bartter syndrome, Gitelman syndrome, EAST syndrome and Liddle syndrome) characterized by hypokalemia and alkalosis. Further detailed explanations are provided for pathogenic genes and functional proteins, clinical manifestations, intrinsic relationship between genotype and clinical phenotype, diagnostic clues, differential diagnosis, and treatment strategies for these diseases.
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Affiliation(s)
- Wenkai Guo
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China
| | - Pengcheng Ji
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
| | - Yuansheng Xie
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China.
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China.
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3
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Filler G, Geda R, Salerno F, Zhang YC, de Ferris MEDG, McIntyre CW. Management of severe polyuria in idiopathic Fanconi syndrome. Pediatr Nephrol 2021; 36:3621-3626. [PMID: 34427794 DOI: 10.1007/s00467-021-05213-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Polyuria is a common problem in patients with tubular diseases, especially for those with CKD and high-output Fanconi syndrome. There are currently no guidelines on how to treat debilitating polyuria, in children or adults, and vasopressin is usually not effective. CASE-DIAGNOSIS/TREATMENT A 13-year-old female with idiopathic Fanconi syndrome and an eGFR of 69 mL/min/1.73 m2 was severely affected by polyuria of 5 L per day (voiding at least 11 times during the day and up to 8 times at night), impacting her mood (measured by the RCADS-child) and academic performance at school. In the absence of guidelines and with literature discouraging the use of indomethacin in this condition, we attempted indomethacin treatment at a dose of 2 mg/kg divided in two doses with substantial success. Urine output dropped to 2.5L and this was accompanied by a substantial decrease of her sodium wasting from 24.6 to 7.7 mmol/kg/day. Over the course of 18 months, the patient's eGFR dropped temporarily to 60 mL/min/1.73 m2 and was 68 mL/min/1.73 m2 at last follow-up. However, a sodium-23 (23Na) MRI of her thigh revealed ongoing moderate sodium decrease in her skin and substantial Na+ decrease in her muscle when compared to age-matched peers with normal kidney function. CONCLUSIONS Indomethacin may be a safe and effective treatment option for polyuria in idiopathic Fanconi syndrome.
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Affiliation(s)
- Guido Filler
- Department of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, Ontario, N6A 5W9, London, Canada. .,Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada. .,Pathology & Laboratory Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada. .,Children's Health Research Institute, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada. .,Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada.
| | - Rishika Geda
- Children's Health Research Institute, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada.,Medical Sciences, University of Western Ontario, London, Ontario, Canada
| | - Fabio Salerno
- Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada.,Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Yun Cong Zhang
- Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada
| | | | - Christopher William McIntyre
- Department of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, Ontario, N6A 5W9, London, Canada.,Pathology & Laboratory Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada.,Children's Health Research Institute, University of Western Ontario, 800 Commissioners Road East, E3-206, London, Ontario, N6A 5W9, Canada.,Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada.,Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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Bamgbola OF, Ahmed Y. Differential diagnosis of perinatal Bartter, Bartter and Gitelman syndromes. Clin Kidney J 2020; 14:36-48. [PMID: 33564404 PMCID: PMC7857843 DOI: 10.1093/ckj/sfaa172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/29/2020] [Indexed: 12/20/2022] Open
Abstract
The common finding of hypokalemic alkalosis in several unrelated disorders may confound the early diagnosis of salt-losing tubulopathy (SLT). Antenatal Bartter syndrome (BS) must be considered in idiopathic early-onset polyhydramnios. Fetal megabladder in BS may allow its distinction from third-trimester polyhydramnios that occurs in congenital chloride diarrhea (CCD). Fetal megacolon occurs in CCD while fecal chloride >90 mEq/L in infants is diagnostic. Failure-to-thrive, polydipsia and polyuria in early childhood are the hallmarks of classic BS. Unlike BS, there is low urinary chloride in hypokalemic alkalosis of intractable emesis and cystic fibrosis. Rarely, renal salt wasting may result from cystinosis, Dent disease, disorders of paracellular claudin-10b and Kir4.1 potassium-channel deficiency. Acquired BS may result from calcimimetic up-regulation of a calcium-sensing receptor or autoantibody inactivation of sodium chloride co-transporters in Sjögren syndrome. A relatively common event of heterozygous gene mutations for Gitelman syndrome increases the likelihood of its random occurrence in certain diseases of adult onset. Finally, diuretic abuse is the most common differential diagnosis of SLT. Unlike the persistent elevation in BS, urinary chloride concentration losses waxes and wanes on day-to-day assessment in patients with diuretic misuse.
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Affiliation(s)
- Oluwatoyin Fatai Bamgbola
- Department of Pediatrics, Division of Pediatric Nephrology, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Youssef Ahmed
- Department of Pediatrics, Kings County Hospital, Brooklyn, NY, USA
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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6
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Abstract
Bartter syndrome is an inherited renal tubular disorder caused by a defective salt reabsorption in the thick ascending limb of loop of Henle, resulting in salt wasting, hypokalemia, and metabolic alkalosis. Mutations of several genes encoding the transporters and channels involved in salt reabsorption in the thick ascending limb cause different types of Bartter syndrome. A poor phenotype-genotype relationship due to the interaction with other cotransporters and different degrees of compensation through alternative pathways is currently reported. However, phenotypic identification still remains the first step to guide the suspicion of Bartter syndrome. Given the rarity of the syndrome, and the lack of genetic characterization in most cases, limited clinical evidence for treatment is available and the therapy is based mainly on the comprehension of renal physiology and relies on the physician's personal experiences. A better understanding of the mutated channels and transporters could possibly generate targets for specific treatment in the future, also encompassing drugs aiming to correct deficiencies in folding or plasma membrane expression of the mutated proteins.
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Affiliation(s)
- Tamara da Silva Cunha
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
| | - Ita Pfeferman Heilberg
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
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7
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Furosemide-induced tubular dysfunction responding to prostaglandin synthesis inhibitor therapy in a child with nephrotic syndrome. CEN Case Rep 2018; 7:195-197. [PMID: 29568987 DOI: 10.1007/s13730-018-0324-3] [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: 11/18/2017] [Accepted: 03/20/2018] [Indexed: 10/17/2022] Open
Abstract
Furosemide is one of the most common drug used to treat anasarca in childhood nephrotic syndrome. It has minimal side effects on short-term usage, but prolonged use can result in polyuria, hypokalemia and metabolic alkalosis. This pseudo-bartter complication can be treated by discontinuation of the drug with adequate potassium replacement. We report a child who was given furosemide for 20 days elsewhere to treat the edema due to nephrotic syndrome and then presented to us with bartter-like syndrome. Furosemide was discontinued and potassium replacement was initiated. However, the child continued to have polyuria leading to repeated episodes of hypotensive shock. In view of severe symptoms, she was given a short course of oral indomethacin for 6 days, to which she responded. This case highlights the fact that indomethacin can provide symptomatic improvement in furosemide induced pseudo-bartter.
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8
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Li D, Tian L, Hou C, Kim CE, Hakonarson H, Levine MA. Association of Mutations in SLC12A1 Encoding the NKCC2 Cotransporter With Neonatal Primary Hyperparathyroidism. J Clin Endocrinol Metab 2016; 101:2196-200. [PMID: 26963954 PMCID: PMC4870850 DOI: 10.1210/jc.2016-1211] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Primary hyperparathyroidism with hypercalciuria has not been described in the newborn period. OBJECTIVE Our objectives are to identify the genetic basis for neonatal primary hyperparathyroidism in a family with 2 affected children. SUBJECTS An African American boy presenting with mild neonatal primary hyperparathyroidism and hypercalciuria was evaluated at The Children's Hospital of Philadelphia. His older brother with neonatal primary hyperparathyroidism had died in infancy of multiple organ failure. METHODS We collected clinical and biochemical data and performed exome sequencing analysis on DNA from the patient and his unaffected mother after negative genetic testing for known causes of primary hyperparathyroidism. RESULTS Exome sequencing followed by Sanger sequencing disclosed 2 heterozygous mutations, c.1883C>A, p.(A628D) and c.2786_2787insC, p.(T931fsX10), in the SLC12A1 gene, which was previously implicated in antenatal type 1 Bartter syndrome. Sanger sequencing confirmed the 2 mutations in the proband and his deceased brother; both parents were heterozygous for different mutations and an unaffected sister was homozygous for wild-type alleles. CONCLUSIONS These results demonstrate a previously unrecognized association between neonatal primary hyperparathyroidism and mutation of SLC12A1, the cause of antenatal Bartter syndrome type 1, and suggest that the loss of sodium-potassium-chloride cotransporter-2 cotransporter activity influences parathyroid gland function.
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Affiliation(s)
- Dong Li
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Lifeng Tian
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Cuiping Hou
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Cecilia E Kim
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Hakon Hakonarson
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Michael A Levine
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
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Castrop H, Schießl IM. Physiology and pathophysiology of the renal Na-K-2Cl cotransporter (NKCC2). Am J Physiol Renal Physiol 2014; 307:F991-F1002. [PMID: 25186299 DOI: 10.1152/ajprenal.00432.2014] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Na-K-2Cl cotransporter (NKCC2; BSC1) is located in the apical membrane of the epithelial cells of the thick ascending limb of the loop of Henle (TAL). NKCC2 facilitates ∼20–25% of the reuptake of the total filtered NaCl load. NKCC2 is therefore one of the transport proteins with the highest overall reabsorptive capacity in the kidney. Consequently, even subtle changes in NKCC2 transport activity considerably alter the renal reabsorptive capacity for NaCl and eventually lead to perturbations of the salt and water homoeostasis. In addition to facilitating the bulk reabsorption of NaCl in the TAL, NKCC2 transport activity in the macula densa cells of the TAL constitutes the initial step of the tubular-vascular communication within the juxtaglomerular apparatus (JGA); this communications allows the TAL to modulate the preglomerular resistance of the afferent arteriole and the renin secretion from the granular cells of the JGA. This review provides an overview of our current knowledge with respect to the general functions of NKCC2, the modulation of its transport activity by different regulatory mechanisms, and new developments in the pathophysiology of NKCC2-dependent renal NaCl transport.
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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10
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Liu Y, Jia Z, Sun Y, Zhou L, Downton M, Chen R, Zhang A, Yang T. Postnatal regulation of 15-hydroxyprostaglandin dehydrogenase in the rat kidney. Am J Physiol Renal Physiol 2014; 307:F388-95. [PMID: 24647712 DOI: 10.1152/ajprenal.00512.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cyclooxygenase 2 (COX-2) has an established role in postnatal kidney development. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is recently identified as an endogenous inhibitor of COX-2, limiting the production of COX-2-derived prostanoids in several pathological conditions. The present study was undertaken to examine the regulation of renal 15-PGDH expression during postnatal kidney development in rats compared with COX-2. qRT-PCR and immunoblotting demonstrated that 15-PGDH mRNA and protein in the kidney were present in neonates, peaked in the second postnatal week, and then declined sharply to very low level in adulthood. Immunostaining demonstrated that at the second postnatal week, renal 15-PGDH protein was predominantly found in the proximal tubules stained positive for Na/H exchanger 3 and brush borders (periodic acid-Schiff), whereas COX-2 protein was restricted to macular densa and adjacent thick ascending limbs. Interestingly, in the fourth postnatal week, 15-PGDH protein was redistributed to thick ascending limbs stained positive for the Na-K-2Cl cotransporter. After 6 wk of age, 15-PGDH protein was found in the granules in subsets of the proximal tubules. Overall, these results support a possibility that 15-PGDH may regulate postnatal kidney development through interaction with COX-2.
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Affiliation(s)
- Ying Liu
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lke City, Utah
| | - Zhanjun Jia
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lke City, Utah
| | - Ying Sun
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lke City, Utah
| | - Li Zhou
- Institute of Hypertension, Sun Yat-sen University School of Medicine, Guangzhou, China
| | - Maicy Downton
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lke City, Utah
| | - Ren Chen
- Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China; and
| | - Aihua Zhang
- Department of Nephrology, Nanjing Children's Hospital, Affiliated to Nanjing Medical University, Nanjing, China
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lke City, Utah; Institute of Hypertension, Sun Yat-sen University School of Medicine, Guangzhou, China;
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11
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Ferreri NR, Hao S, Pedraza PL, Escalante B, Vio CP. Eicosanoids and tumor necrosis factor-alpha in the kidney. Prostaglandins Other Lipid Mediat 2011; 98:101-6. [PMID: 22101002 DOI: 10.1016/j.prostaglandins.2011.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/31/2011] [Accepted: 11/03/2011] [Indexed: 12/14/2022]
Abstract
The thick ascending limb of Henle's loop (TAL) is capable of metabolizing arachidonic acid (AA) by cytochrome P450 (CYP450) and cyclooxygenase (COX) pathways and has been identified as a nephron segment that contributes to salt-sensitive hypertension. Previous studies demonstrated a prominent role for CYP450-dependent metabolism of AA to products that inhibited ion transport pathways in the TAL. However, COX-2 is constitutively expressed along all segments of the TAL and is increased in response to diverse stimuli. The ability of Tamm-Horsfall glycoprotein, a selective marker of cortical TAL (cTAL) and medullary (mTAL), to bind TNF and localize it to this nephron segment prompted studies to determine the capacity of mTAL cells to produce TNF and determine its effects on mTAL function. The colocalization of calcium-sensing receptor (CaR) and COX-2 in the TAL supports the notion that activation of CaR induces TNF-dependent COX-2 expression and PGE₂ synthesis in mTAL cells. Additional studies showed that TNF produced by mTAL cells inhibits ⁸⁶Rb uptake, an in vitro correlate of natriuresis, in an autocrine- and COX-2-dependent manner. The molecular mechanism for these effects likely includes inhibition of Na⁺-K⁺-2Cl⁻ cotransporter (NKCC2) expression and trafficking.
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Affiliation(s)
- Nicholas R Ferreri
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA.
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12
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Kawada N, Moriyama T, Kitamura H, Yamamoto R, Furumatsu Y, Matsui I, Takabatake Y, Nagasawa Y, Imai E, Wilcox CS, Rakugi H, Isaka Y. Towards developing new strategies to reduce the adverse side-effects of nonsteroidal anti-inflammatory drugs. Clin Exp Nephrol 2011; 16:25-9. [DOI: 10.1007/s10157-011-0492-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 01/11/2011] [Indexed: 11/24/2022]
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13
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Seyberth HW, Schlingmann KP. Bartter- and Gitelman-like syndromes: salt-losing tubulopathies with loop or DCT defects. Pediatr Nephrol 2011; 26:1789-802. [PMID: 21503667 PMCID: PMC3163795 DOI: 10.1007/s00467-011-1871-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 03/09/2011] [Accepted: 03/09/2011] [Indexed: 12/11/2022]
Abstract
Salt-losing tubulopathies with secondary hyperaldosteronism (SLT) comprise a set of well-defined inherited tubular disorders. Two segments along the distal nephron are primarily involved in the pathogenesis of SLTs: the thick ascending limb of Henle's loop, and the distal convoluted tubule (DCT). The functions of these pre- and postmacula densa segments are quite distinct, and this has a major impact on the clinical presentation of loop and DCT disorders - the Bartter- and Gitelman-like syndromes. Defects in the water-impermeable thick ascending limb, with its greater salt reabsorption capacity, lead to major salt and water losses similar to the effect of loop diuretics. In contrast, defects in the DCT, with its minor capacity of salt reabsorption and its crucial role in fine-tuning of urinary calcium and magnesium excretion, provoke more chronic solute imbalances similar to the effects of chronic treatment with thiazides. The most severe disorder is a combination of a loop and DCT disorder similar to the enhanced diuretic effect of a co-medication of loop diuretics with thiazides. Besides salt and water supplementation, prostaglandin E2-synthase inhibition is the most effective therapeutic option in polyuric loop disorders (e.g., pure furosemide and mixed furosemide-amiloride type), especially in preterm infants with severe volume depletion. In DCT disorders (e.g., pure thiazide and mixed thiazide-furosemide type), renin-angiotensin-aldosterone system (RAAS) blockers might be indicated after salt, potassium, and magnesium supplementation are deemed insufficient. It appears that in most patients with SLT, a combination of solute supplementation with some drug treatment (e.g., indomethacin) is needed for a lifetime.
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Affiliation(s)
- Hannsjörg W. Seyberth
- Department of Pediatrics and Adolescent Medicine, Philipps University, Marburg, Germany ,Lazarettgarten 23, 76829 Landau, Germany
| | - Karl P. Schlingmann
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
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15
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Brochard K, Boyer O, Blanchard A, Loirat C, Niaudet P, Macher MA, Deschenes G, Bensman A, Decramer S, Cochat P, Morin D, Broux F, Caillez M, Guyot C, Novo R, Jeunemaître X, Vargas-Poussou R. Phenotype-genotype correlation in antenatal and neonatal variants of Bartter syndrome. Nephrol Dial Transplant 2008; 24:1455-64. [PMID: 19096086 DOI: 10.1093/ndt/gfn689] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Ante/neonatal Bartter syndrome (BS) is a hereditary salt-losing tubulopathy due to mutations in genes encoding proteins involved in NaCl reabsorption in the thick ascending limb of Henle's loop. Our aim was to study the frequency, clinical characteristics and outcome of each genetic subtype. METHODS Charts of 42 children with mutations in KCNJ1 (n = 19), SLC12A1 (n = 13) CLCNKB (n = 6) or BSND (n = 4) were retrospectively analysed. The median follow-up was 8.3 [0.4-18.0] years. RESULTS We describe 24 new mutations: 10 in KCNJ1, 11 in SLC12A1 and 3 in CLCNKB. The onset of polyhydramnios, birth term, height and weight were similar for all groups; three patients had no history of polyhydramnios or premature birth and had CLCNKB mutations according to a less severe renal sodium wasting. Contrasting with these data, patients with CLCNKB had the lowest potassium (P = 0.006 versus KCNJ1 and P = 0.034 versus SLC12A1) and chloride plasma concentrations (P = 0.039 versus KCNJ1 and P = 0.024 versus SLC12A1) and the highest bicarbonataemia (P = 0.026 versus KCNJ1 and P = 0.014 versus SLC12A1). Deafness at diagnosis was constant in patients with BSND mutations; transient neonatal hyperkalaemia was present in two-thirds of the children with KCNJ1 mutations. Nephrocalcinosis was constant in KCNJ1 and SLC12A1 but not in BSND and CLCNKB patients. In most cases, water/electrolyte supplementation + indomethacin led to catch-up growth. Three patients developed chronic renal failure: one with KCNJ1 mutations during the second decade of age and two with CLCNKB and BSND mutations and without nephrocalcinosis during the first year of life. CONCLUSIONS We confirmed in a large cohort of ante/ neonatal BS that deafness, transient hyperkalaemia and severe hypokalaemic hypochloraemic alkalosis orientate molecular investigations to BSND, KCNJ1 and CLCNKB genes, respectively. Chronic renal failure is a rare event, associated in this cohort with three genotypes and not always associated with nephrocalcinosis.
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Affiliation(s)
- Karine Brochard
- Hôpitaux de Toulouse, Université Paul Sabathier, Département de Pédiatrie, Centre de Référence des Maladies Rénales Rares, Toulouse F31000, France
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16
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Seyberth HW. An improved terminology and classification of Bartter-like syndromes. ACTA ACUST UNITED AC 2008; 4:560-7. [PMID: 18695706 DOI: 10.1038/ncpneph0912] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Accepted: 07/04/2008] [Indexed: 12/15/2022]
Abstract
This Review outlines a terminology and classification of Bartter-like syndromes that is based on the underlying causes of these inherited salt-losing tubulopathies and is, therefore, more clinically relevant than the classical definition. Three major types of salt-losing tubulopathy can be defined: distal convoluted tubule dysfunction leading to hypokalemia (currently known as Gitelman or Bartter syndrome), the more-severe condition of polyuric loop dysfunction (often referred to as antenatal Bartter or hyperprostaglandin E syndrome), and the most-severe condition of combined loop and distal convoluted tubule dysfunction (antenatal Bartter or hyperprostaglandin E syndrome with sensorineural deafness). These three subtypes can each be further subdivided according to the identity of the defective ion transporter or channel: the sodium-chloride cotransporter NCCT or the chloride channel ClC-Kb in distal convoluted tubule dysfunction; the sodium-potassium-chloride cotransporter NKCC2 or the renal outer medullary potassium channel in loop dysfunction; and the chloride channels ClC-Ka and ClC-Kb or their beta-subunit Barttin in combined distal convoluted tubule and loop dysfunction. This new classification should help clinicians to better understand the pathophysiology of these syndromes and choose the most appropriate treatment for affected patients, while avoiding potentially harmful diagnostic and therapeutic approaches.
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Affiliation(s)
- Hannsjörg W Seyberth
- Center for Pediatric and Adolescent Medicine, Philipps University, Marburg, Germany.
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Castrop H, Schnermann J. Isoforms of renal Na-K-2Cl cotransporter NKCC2: expression and functional significance. Am J Physiol Renal Physiol 2008; 295:F859-66. [PMID: 18495801 DOI: 10.1152/ajprenal.00106.2008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renal Na-K-2Cl cotransporter (NKCC2, BSC1) is selectively expressed in the apical membrane of cells of the thick ascending limb of the loop of Henle (TAL) and macula densa. NKCC2-dependent salt transport constitutes the major apical entry pathway for transepithelial salt reabsorption in the TAL. Although NKCC2 is encoded by a single gene (Slc12a1), differential splicing of the NKCC2 pre-mRNA results in the formation of several alternate transcripts. Thus three full-length splice isoforms of NKCC2 differ in their variable exon 4, resulting in transcripts for NKCC2B, NKCC2A, and NKCC2F. In addition to full-length isoforms, variants with truncated COOH-terminal ends have been described. The various splice isoforms of NKCC2 differ in their localization along the TAL and in their transport characteristics. Data in the literature are reviewed to assess the principles of NKCC2 differential splicing, the localization of NKCC2 splice isoforms along the TAL in various species, and the functional characteristics of the splice isoforms. In addition, we discuss the functional significance of NKCC2 isoforms for TAL salt retrieval and for the specific salt sensor function of macula densa cells based on studies using isoform-specific NKCC2-knockout mice. We suggest that different NKCC2 splice variants cooperate in salt retrieval along the TAL and that the coexpression of two splice variants (NKCC2B and NKCC2A) in the macula densa cells facilitates efficient salt sensing over wide ranges of fluctuating salt concentrations.
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Affiliation(s)
- Hayo Castrop
- Physiologisches Institut der Universität Regensburg, Universitätsstr. 31, D-93040 Regensburg, Germany.
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Antonucci R, Cuzzolin L, Arceri A, Fanos V. Urinary prostaglandin E2 in the newborn and infant. Prostaglandins Other Lipid Mediat 2007; 84:1-13. [PMID: 17643883 DOI: 10.1016/j.prostaglandins.2007.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2006] [Revised: 04/22/2007] [Accepted: 04/23/2007] [Indexed: 10/23/2022]
Abstract
Prostaglandin E(2) (PGE(2)) belongs to a family of biologically active lipids derived from the 20-carbon essential fatty acids. Renal PGE(2) is involved in the development of the kidney; it also contributes to regulate renal perfusion and glomerular filtration rate, and controls water and electrolyte balance. Furthermore, this mediator protects the kidney against excessive functional changes during the transition from fetal to extrauterine life, when it counteracts the vasoconstrictive effects of high levels of angiotensin II and other mediators. There is evidence that PGE(2) plays an important pathophysiological role in neonatal conditions of renal stress, and in congenital or acquired nephropaties. Thus, measurement of urinary PGE(2) as an index of renal synthesis of this primary prostaglandin may represent a non-invasive and sensitive method of investigating the homeostatic function of the kidney in early life. The aim of this literature review is to examine urinary PGE(2) as a non-invasive marker of renal homeostasis in the newborn and infant under both physiological and pathological conditions, or during treatments with widely used, potentially toxic drugs.
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Affiliation(s)
- Roberto Antonucci
- Department of Pediatrics and Clinical Medicine-Section of Neonatal Intensive Care Unit, University of Cagliari, Cagliari, Italy
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Girschick HJ, Haubitz I, Hiort O, Schneider P. Long-term follow-up of bone mineral density in childhood hypophosphatasia. Joint Bone Spine 2007; 74:263-9. [PMID: 17420150 DOI: 10.1016/j.jbspin.2006.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2005] [Accepted: 06/07/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Hypophosphatasia (HP; MIM 241510) is an inborn error of bone metabolism, characterized by a genetic defect in the gene of the tissue-non-specific alkaline phosphatase TNSALP. Long-term data on bone mineral density measurements are not available. METHODS We have analyzed changes of bone mineral density (pQCT and DXA) prospectively during 4years of follow-up in a cohort of 6 patients with childhood HP. RESULTS At diagnosis hypermineralization of the trabecular bone in the metaphyseal area of long bones in affected children was noted. During 4 years of follow-up a gradual, significant decrease of mineralization was noted in the radial metaphyses. In contrast, BMC by DXA and total body DXA values were stable in comparison to healthy controls. During follow-up a systemic hyperprostaglandinism was documented in the majority of the patients. Non-steroidal anti-inflammatory drug treatment was evaluated by measuring prostaglandin excretion in the urine. CONCLUSIONS Metaphyseal hypermineralization in childhood HP, which might be a compensation for a mechanically incompetent bony structure, decreased over time. There might be a pathophysiological link to continually elevated systemic prostaglandins.
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Affiliation(s)
- Hermann Josef Girschick
- Children's Hospital, Section of pediatric rheumatology and osteology, Universitäts-Kinderklinik, University of Würzburg, Josef-Schneider-Strasse 2, Würzburg 97080, Germany.
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20
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Girschick HJ, Schneider P, Haubitz I, Hiort O, Collmann H, Beer M, Shin YS, Seyberth HW. Effective NSAID treatment indicates that hyperprostaglandinism is affecting the clinical severity of childhood hypophosphatasia. Orphanet J Rare Dis 2006; 1:24. [PMID: 16803637 PMCID: PMC1533806 DOI: 10.1186/1750-1172-1-24] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 06/28/2006] [Indexed: 11/30/2022] Open
Abstract
Background Hypophosphatasia (HP) is an inborn error of bone metabolism characterized by a genetic defect in the gene encoding the tissue-nonspecific alkaline phosphatase (TNSALP). There is a lack of knowledge as to how the variability and clinical severity of the HP phenotype (especially pain and walking impairment) are related to metabolic disturbances or impairments, subsequent to the molecular defect. Methods We analyzed the changes in clinical symptoms and the prostaglandin (PG) metabolism in response to treatment with non-steroidal anti-inflammatory drugs (NSAIDs) in six children affected by childhood HP. In addition, by exposing HP fibroblasts to pyridoxal phosphate and/or calcium pyrophosphate in vitro, we analyzed whether the alterations in PG levels are sequelae related to the metabolic defect. Results Childhood HP patients, who often complain about pain in the lower limbs without evident fractures, have systemic hyperprostaglandinism. Symptomatic anti-inflammatory treatment with NSAIDs significantly improved pain-associated physical impairment. Calcium pyrophosphate, but not pyridoxal phosphate, induced cyclooxygenase-2 (COX-2) gene expression and PG production in HP and normal fibroblasts in vitro. Conclusion Clinical features of childhood HP related to pain in the lower legs may be, at least in part, sequelae related to elevated PG levels, secondary to the primary metabolic defect. Consequently, NSAID treatment does improve the clinical features of childhood HP.
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Affiliation(s)
- HJ Girschick
- Children's Hospital, University of Würzburg, Germany
| | - P Schneider
- Clinic for Nuclear Medicine, University of Würzburg, Germany
| | - I Haubitz
- Children's Hospital, University of Würzburg, Germany
| | - O Hiort
- Children's Hospital, University of Lübeck, Germany
| | - H Collmann
- Section of Pediatric Neurosurgery, University of Würzburg, Germany
| | - M Beer
- Dept. of Radiology, Section of Pediatric Radiology, University of Würzburg, Germany
| | - YS Shin
- Children's Hospital, University of Munich, Germany
| | - HW Seyberth
- Children's Hospital, University of Marburg, Germany
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21
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Sauvant C, Holzinger H, Gekle M. Prostaglandin E2 inhibits its own renal transport by downregulation of organic anion transporters rOAT1 and rOAT3. J Am Soc Nephrol 2005; 17:46-53. [PMID: 16338963 DOI: 10.1681/asn.2005070727] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prostaglandin E2 (PGE2) is the principal mediator of fever and inflammation. Recently, evidence emerged that during febrile response, PGE2 that is generated in the periphery enters the hypothalamus and contributes to the maintenance of fever. In a rat model of fever generation, peripheral PGE2 is increased, whereas clearance by metabolism of peripheral PGE2 is downregulated. The major route of PGE2 excretion is via the renal proximal tubular organic anion secretory system, where basolateral uptake that is mediated by renal organic anion transporter 1 (rOAT1) and rOAT3 is rate limiting. Therefore, it was hypothesized that PGE2 itself will abolish its excretion by rOAT1 or rOAT3. Fluorescein was used as a prototypic organic anion, and NRK-52E cells from rat served as a proximal tubular model system. PGE2 time-dependently downregulates basolateral organic anion uptake, without affecting cell volume or cell protein, recirculation of counter ions, or proximal tubular transport systems in general. In addition, PGE2 diminishes expression of both rOAT1 and rOAT3. Both organic anion uptake and expression of rOAT1 and rOAT3 are dose-dependently downregulated by PGE2. These findings suggest that during fever or inflammation, renal secretory transport of PGE2 is reduced, contributing to elevated PGE2 levels in blood. These data fit into the hypothetical concept of peripheral PGE2's playing a significant role in fever. The described regulatory mechanism may also be of relevance in chronic inflammatory events. Moreover, the data presented could explain why increased plasma urate levels occur in diseases that go along with increased levels of PGE2.
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Affiliation(s)
- Christoph Sauvant
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070 Würzburg, Germany.
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22
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Nüsing RM, Treude A, Weissenberger C, Jensen B, Bek M, Wagner C, Narumiya S, Seyberth HW. Dominant role of prostaglandin E2 EP4 receptor in furosemide-induced salt-losing tubulopathy: a model for hyperprostaglandin E syndrome/antenatal Bartter syndrome. J Am Soc Nephrol 2005; 16:2354-62. [PMID: 15976003 DOI: 10.1681/asn.2004070556] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Increased formation of prostaglandin E2 (PGE2) is a key part of hyperprostaglandin E syndrome/antenatal Bartter syndrome (HPS/aBS), a renal disease characterized by NaCl wasting, water loss, and hyperreninism. Inhibition of PGE2 formation by cyclo-oxygenase inhibitors significantly lowers patient mortality and morbidity. However, the pathogenic role of PGE2 in HPS/aBS awaits clarification. Chronic blockade of the Na-K-2Cl co-transporter NKCC2 by diuretics causes symptoms similar to HPS/aBS and provides a useful animal model. In wild-type (WT) mice and in mice lacking distinct PGE2 receptors (EP1-/-, EP2-/-, EP3-/-, and EP4-/-), the effect of chronic furosemide administration (7 d) on urine output, sodium and potassium excretion, and renin secretion was determined. Furthermore, furosemide-induced diuresis and renin activity were analyzed in mice with defective PGI2 receptors (IP-/-). In all animals studied, furosemide stimulated a rise in diuresis and electrolyte excretion. However, this effect was blunted in EP1-/-, EP3-/-, and EP4-/- mice. Compared with WT mice, no difference was observed in EP2-/- and IP-/- mice. The furosemide-induced increase in plasma renin concentration was significantly decreased in EP4-/- mice and to a lesser degree also in IP-/- mice. Pharmacologic inhibition of EP4 receptors in furosemide-treated WT mice with the specific antagonist ONO-AE3-208 mimicked the changes in renin mRNA expression, plasma renin concentration, diuresis, and sodium excretion seen in EP4-/- mice. The GFR in EP4-/- mice was not changed compared with that in WT mice, which indicated that blunted diuresis and salt loss seen in EP4-/- mice were not a consequence of lower GFR. In summary, these findings demonstrate that the EP4 receptor mediates PGE2-induced renin secretion and that EP1, EP3, and EP4 receptors all contribute to enhanced PGE2-mediated salt and water excretion in the HPS/aBS model.
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MESH Headings
- Actins/metabolism
- Animals
- Bartter Syndrome/metabolism
- Bartter Syndrome/pathology
- Cyclooxygenase Inhibitors/pharmacology
- Dinoprostone/metabolism
- Disease Models, Animal
- Diuresis
- Diuretics/pharmacology
- Enzyme Inhibitors/pharmacology
- Furosemide/pharmacology
- Glomerular Filtration Rate
- Kidney Tubules/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Models, Statistical
- Prostaglandins E/metabolism
- RNA, Messenger/metabolism
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Receptors, Prostaglandin E, EP4 Subtype
- Renin/metabolism
- Ribonucleases/metabolism
- Salts/metabolism
- Salts/pharmacology
- Sodium/metabolism
- Sodium Chloride/pharmacology
- Sodium Chloride, Dietary/pharmacology
- Sodium-Potassium-Chloride Symporters/metabolism
- Symporters/antagonists & inhibitors
- Time Factors
- K Cl- Cotransporters
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Affiliation(s)
- Rolf M Nüsing
- Institute of Clinical Pharmacology, Johann Wolfgang Goethe-University, Theodor Stern Kai 7, Frankfurt 60590, Germany.
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Jeck N, Schlingmann KP, Reinalter SC, Kömhoff M, Peters M, Waldegger S, Seyberth HW. Salt handling in the distal nephron: lessons learned from inherited human disorders. Am J Physiol Regul Integr Comp Physiol 2005; 288:R782-95. [PMID: 15793031 DOI: 10.1152/ajpregu.00600.2004] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The molecular basis of inherited salt-losing tubular disorders with secondary hypokalemia has become much clearer in the past two decades. Two distinct segments along the nephron turned out to be affected, the thick ascending limb of Henle's loop and the distal convoluted tubule, accounting for two major clinical phenotypes, hyperprostaglandin E syndrome and Bartter-Gitelman syndrome. To date, inactivating mutations have been detected in six different genes encoding for proteins involved in renal transepithelial salt transport. Careful examination of genetically defined patients (“human knockouts”) allowed us to determine the individual role of a specific protein and its contribution to the overall process of renal salt reabsorption. The recent generation of several genetically engineered mouse models that are deficient in orthologous genes further enabled us to compare the human phenotype with the animal models, revealing some unexpected interspecies differences. As the first line treatment in hyperprostaglandin E syndrome includes cyclooxygenase inhibitors, we propose some hypotheses about the mysterious role of PGE2in the etiology of renal salt-losing disorders.
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Affiliation(s)
- Nikola Jeck
- MD, Univ. Children's Hospital, Philipps-Univ., Deutschhausstrasse 12, D-35037 Marburg, Germany. )
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Nüsing RM, Seyberth HW. The role of cyclooxygenases and prostanoid receptorsin furosemide-like salt losing tubulopathy: the hyperprostaglandin E syndrome. ACTA ACUST UNITED AC 2004; 181:523-8. [PMID: 15283766 DOI: 10.1111/j.1365-201x.2004.01326.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperprostaglandin E syndrome/antenatal Bartter syndrome is characterized by NaCl wasting and volume depletion, juxtaglomerula hypertrophy, hyperreninism and secondary hyperaldosteronism. Primary causes are mutations in the gene for Na-K-2Cl-cotransporter, NKCC2, or for potassium channel, ROMK, responsible for medullary NaCl malabsorption. Most intriguing aspect of the syndrome is the association with a massively increased renal prostaglandin production which contributes substantially to the clinical picture of the patients. Therefore the term hyperprostaglandin E syndrome has been introduced. It is unclear how prostaglandins aggravate the NaCl transport deficiency. Aspects to prostaglandin synthesis and receptor-mediated function within the kidney in patients suffering from hyperprostaglandin E syndrome/antenatal Bartter syndrome will be discussed.
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Affiliation(s)
- R M Nüsing
- Department of Pediatrics, Philipp's University, Marburg, Germany
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25
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Reinalter SC, Jeck N, Peters M, Seyberth HW. Pharmacotyping of hypokalaemic salt-losing tubular disorders. ACTA ACUST UNITED AC 2004; 181:513-21. [PMID: 15283765 DOI: 10.1111/j.1365-201x.2004.01325.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
UNLABELLED Long standing confusion exists in the terminology of hypokalaemic salt-losing tubulopathies (SLTs). SLTs are autosomal recessively transmitted and characterized by normotensive secondary hyperreninism/hyperaldosteronism with hypokalaemic metabolic alkalosis. Historically, four phenotypical variants have been described: (1) the (classic) Bartter syndrome (cBS), (2) the hypomagnesaemic hypocalciuric Gitelman syndrome (GS), (3) the hypercalciuric hyperprostaglandin-E-syndrome (HPS) or antenatal Bartter syndrome (aBS) and (4) the hyperprostaglandin-E-syndrome with sensorineural deafness (HPS + SND). The latter two syndromes are the most severe variants with antenatal manifestation with polyhydramnios and life-threatening course of salt- and water-loss. Defects in five renal membrane proteins involved in electrolyte reabsorption have been identified: In HPS-patients mutations in (1) either the furosemide-sensitive sodium-potassium-chloride cotransporter NKCC2, or (2) in the potassium channel ROMK have been identified, and (3) HPS + SND is caused by mutations in the beta-subunit of the chloride channels ClC-Kb and -Ka (named barttin), all mimicking the major pharmacological effects of furosemide with minor potassium-wasting in ROMK-patients as seen in patients treated with simultaneous furosemide and amiloride, and minor calcium-wasting in Barttin-patients resembling the combination of furosemide and thiazides. (4) cBS is caused by mutations in the chloride channel ClC-Kb with similar clinical characteristics as seen under combination of thiazides and furosemide, (5) GS is caused by mutations in the thiazide-sensitive sodium-chloride cotransporter NCCT resembling the effect of long-term thiazide administration. CONCLUSION The combination of pharmacology and genetics suggests a new terminology for the above described SLTs: Furosemide-like-SLT for HPS caused by NKCC2-mutations, furosemide/amiloride-like-SLT for HPS caused by ROMK-mutations, furosemide/thiazide-like-SLT for HPS + SND, thiazide/furosemide-like-SLT for cBS, and thiazide-like-SLT for GS.
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Affiliation(s)
- S C Reinalter
- Department of Paediatrics, Philipps University, Marburg, Germany
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26
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Sardani Y, Qin K, Haas M, Aronson AJ, Rosenfield RL. Bartter syndrome complicated by immune complex nephropathy. Case report and literature review. Pediatr Nephrol 2003; 18:913-8. [PMID: 12836094 DOI: 10.1007/s00467-003-1194-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2002] [Revised: 04/07/2003] [Accepted: 04/07/2003] [Indexed: 12/22/2022]
Abstract
The unusual coincidence of Bartter syndrome and C1q nephropathy is described and the literature reviewed. An African-American girl presented at 4 years of age with acute hyponatremic dehydration and failure to thrive. Persistent hypokalemic alkalosis and secondary hyperaldosteronism were found. The case was atypical for Bartter syndrome in that proteinuria (0.19 g/day) was present. Renal biopsy showed juxtaglomerular hyperplasia and C1q nephropathy. Molecular analysis showed deletion of the renal chloride channel gene (CLCNKB) typical of autosomal recessive childhood Bartter syndrome. Chronic sodium and potassium chloride replacement therapy together with indomethacin normalized her metabolic status, and she experienced catch-up growth. Proteinuria persisted, however. This is the first documentation of C1q nephropathy, in mild form, complicating autosomal recessive Bartter syndrome. This case shows the importance of the renal biopsy and of molecular analysis in delineating the cause of atypical nephropathy associated with Bartter syndrome. These findings add to the evidence of a possible association between the congenital syndrome and acquired immune complex nephropathy.
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Affiliation(s)
- Yahya Sardani
- Department of Pediatrics, The University of Chicago Pritzker School of Medicine, 5839 S. Maryland Avenue, Chicago, IL 60637-1470, USA
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Schnermann J. Homer W. Smith Award lecture. The juxtaglomerular apparatus: from anatomical peculiarity to physiological relevance. J Am Soc Nephrol 2003; 14:1681-94. [PMID: 12761271 DOI: 10.1097/01.asn.0000069221.69551.30] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Jurgen Schnermann
- National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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28
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Leonhardt A, Bernert S, Watzer B, Schmitz-Ziegler G, Seyberth HW. Low-dose aspirin in pregnancy: maternal and neonatal aspirin concentrations and neonatal prostanoid formation. Pediatrics 2003; 111:e77-81. [PMID: 12509599 DOI: 10.1542/peds.111.1.e77] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To evaluate maternal and neonatal plasma concentrations of acetylsalicylic acid and salicylic acid and the neonatal endogenous prostanoid formation during low-dose aspirin prophylaxis (LDA; 100 mg daily) in pregnant women. METHODS Concentrations of acetylsalicylic acid and salicylic acid in maternal plasma after at least 4 weeks of LDA (n = 14) and in umbilical cord plasma of newborns after maternal LDA (n = 7) were determined by gas chromatography-mass spectrometry. Platelet and renal formation of thromboxane A2 and the formation of prostaglandin E2 and prostacyclin were evaluated in vivo by quantification of index metabolites in plasma and urine by gas chromatography-mass spectrometry in neonates after maternal LDA (n = 14) and in a control group. RESULTS In the pregnant women, acetylsalicylic acid and salicylic acid concentrations rapidly increased after ingestion of LDA. Acetylsalicylic acid was completely eliminated within 4 hours, whereas salicylic acid was detected with low concentrations at 18 and 21 hours after dosing. In the neonates, acetylsalicylic acid was not detected. Salicylic acid was detected in 1 infant only. Platelet thromboxane A2 formation in the newborn infants was significantly suppressed but recovered within 2 to 3 days after discontinuation of LDA. Renal thromboxane A2 formation and the formation of prostaglandin E2 and prostacyclin were not affected by LDA. CONCLUSION In pregnant women who are treated with LDA, acetylsalicylic acid is not completely inactivated in the portal circulation but reaches the uteroplacental circulation and exerts antiplatelet effects in the fetus and newborn.
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Peters M, Jeck N, Reinalter S, Leonhardt A, Tönshoff B, Klaus G GÜ, Konrad M, Seyberth HW. Clinical presentation of genetically defined patients with hypokalemic salt-losing tubulopathies. Am J Med 2002; 112:183-90. [PMID: 11893344 DOI: 10.1016/s0002-9343(01)01086-5] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE Hypokalemic salt-losing tubulopathies (Bartter-like syndromes) comprise a set of clinically and genetically distinct inherited renal disorders. Mutations in four renal membrane proteins involved in electrolyte reabsorption have been identified in these disorders: the furosemide-sensitive sodium-potassium-chloride cotransporter NKCC2, the potassium channel ROMK, the chloride channel ClC-Kb, and the thiazide-sensitive sodium-chloride cotransporter NCCT. The aim of this study was to characterize the clinical features associated with each mutation in a large cohort of genetically defined patients. PATIENTS AND METHODS The phenotypic characteristics of 65 patients with molecular defects in NKCC2, ROMK, ClC-Kb, or NCCT were collected retrospectively. RESULTS ROMK and NKCC2 patients presented with polyhydramnios, nephrocalcinosis, and hypo- or isosthenuria. Hypokalemia was less severe in the ROMK patients compared with the NKCC2 patients. In contrast, NCCT patients had hypocalciuria, hypomagnesemia, and marked hypokalemia. While this dissociation of renal calcium and magnesium handling was also observed in some ClC-Kb patients, a few ClC-Kb patients presented with hypercalciuria and hypo- or isosthenuria. CONCLUSIONS ROMK, NKCC2, and NCCT mutations usually have uniform clinical presentations, whereas mutations in ClC-Kb occasionally lead to phenotypic overlaps with the NCCT or, less commonly, with the ROMK/NKCC2 cohort. Based on these results, we propose an algorithm for the molecular diagnosis of hypokalemic salt-losing tubulopathies.
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Affiliation(s)
- Melanie Peters
- Department of Pediatrics, Philipps University Marburg, Marburg, Germany
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Abstract
A case of neonatal Bartter syndrome is reported. The baby born pre-term following a pregnancy complicated by polyhydramnios, presented at 7 months of age with failure to thrive, gastroenteritis and facial dysmorphisms. An unusual feature was the absence of the classical biochemical abnormality of hypochloremic alkalosis early in the course of the disease. Metabolic acidosis was the initial manifestation at 5 weeks of age. Awareness of this presentation is important to avoid delay in diagnosis and treatment.
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Affiliation(s)
- Mamta N Muranjan
- Department of Pediatrics, Seth G.S. Medical College, K.E.M. Hospital, Parel, Mumbai, India
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31
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Schnermann J. Sodium transport deficiency and sodium balance in gene-targeted mice. ACTA PHYSIOLOGICA SCANDINAVICA 2001; 173:59-66. [PMID: 11678727 DOI: 10.1046/j.1365-201x.2001.00885.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Animals with induced or natural null mutations in renal NaCl and water transporter genes provide a powerful tool to study the physiological mechanisms that enable the kidney to optimize the match between glomerular filtration rate and tubular reabsorption. Deficiencies in the Na/H exchanger NHE3 and in the water channel aquaporin 1 (AQP1) cause reductions in proximal fluid absorption which are accompanied by proportionate decrements in glomerular filtration rate (GFR). Compensation of the transport defect by a reduction in filtered load is so efficient that clinically symptomatic Na losses are not observed in either NHE3 or AQP1 deficient animals. On the other hand, severe syndromes of salt wasting are caused by loss of function of the Na,K,2Cl-cotransporter (NKCC2) in the thick ascending limb, or of the epithelial Na channel (ENaC) the collecting duct indicating that the severity of Na dysregulation is unrelated to the basal absorption of NaCl in a given nephron segment. In these states, the increased delivery of Na to downstream segments is not monitored by a sensor linked to the site of filtrate formation. In the absence of adaptations in the filtered load intrarenal compensation of a circumscribed NaCl malabsorption by adjustment of NaCl transport in other nephron segments is sometimes insufficient, particularly in the immature kidney of the newborn.
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Affiliation(s)
- J Schnermann
- NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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32
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Jeck N, Reinalter SC, Henne T, Marg W, Mallmann R, Pasel K, Vollmer M, Klaus G, Leonhardt A, Seyberth HW, Konrad M. Hypokalemic salt-losing tubulopathy with chronic renal failure and sensorineural deafness. Pediatrics 2001; 108:E5. [PMID: 11433084 DOI: 10.1542/peds.108.1.e5] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To characterize a rare inherited hypokalemic salt-losing tubulopathy with linkage to chromosome 1p31. METHODS We conducted a retrospective analysis of the clinical data for 7 patients in whom cosegregation of the disease with chromosome 1p31 had been demonstrated. In addition, in 1 kindred, prenatal diagnosis in the second child was established, allowing a prospective clinical evaluation. RESULTS Clinical presentation of the patients was homogeneous and included premature birth attributable to polyhydramnios, severe renal salt loss, normotensive hyperreninemia, hypokalemic alkalosis, and excessive hyperprostaglandin E-uria, which suggested the diagnosis of hyperprostaglandin E syndrome/antenatal Bartter syndrome. However, the response to indomethacin was only poor, accounting for a more severe variant of the disease. The patients invariably developed chronic renal failure. The majority had extreme growth retardation, and motor development was markedly delayed. In addition, all patients turned out to be deaf. CONCLUSION The hypokalemic salt-losing tubulopathy with chronic renal failure and sensorineural deafness represents not only genetically but also clinically a disease entity distinct from hyperprostaglandin E syndrome/antenatal Bartter syndrome. A pleiotropic effect of a single gene defect is most likely causative for syndromic hearing loss.
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MESH Headings
- Adolescent
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Bartter Syndrome/genetics
- Child
- Child, Preschool
- Chromosomes, Human, Pair 1/genetics
- Consanguinity
- Creatinine/blood
- Cyclooxygenase Inhibitors/therapeutic use
- Deafness/genetics
- Dinoprostone/metabolism
- Dinoprostone/urine
- Diuresis
- Female
- Genetic Linkage
- Growth Disorders/genetics
- Haplotypes
- Humans
- Hypokalemia/drug therapy
- Hypokalemia/genetics
- Indomethacin/therapeutic use
- Infant
- Kidney/diagnostic imaging
- Kidney/pathology
- Kidney/ultrastructure
- Kidney Failure, Chronic/diagnosis
- Kidney Failure, Chronic/drug therapy
- Kidney Failure, Chronic/genetics
- Lebanon
- Male
- Pedigree
- Phenotype
- Renal Tubular Transport, Inborn Errors/diagnosis
- Renal Tubular Transport, Inborn Errors/diagnostic imaging
- Renal Tubular Transport, Inborn Errors/drug therapy
- Renal Tubular Transport, Inborn Errors/genetics
- Renal Tubular Transport, Inborn Errors/pathology
- Retrospective Studies
- Syndrome
- Treatment Outcome
- Turkey
- Ultrasonography
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Affiliation(s)
- N Jeck
- Departments of Pediatrics, Marburg, Germany
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Takahashi N, Chernavvsky DR, Gomez RA, Igarashi P, Gitelman HJ, Smithies O. Uncompensated polyuria in a mouse model of Bartter's syndrome. Proc Natl Acad Sci U S A 2000; 97:5434-9. [PMID: 10779555 PMCID: PMC25846 DOI: 10.1073/pnas.090091297] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have used homologous recombination to disrupt the mouse gene coding for the NaK2Cl cotransporter (NKCC2) expressed in kidney epithelial cells of the thick ascending limb and macula densa. This gene is one of several that when mutated causes Bartter's syndrome in humans, a syndrome characterized by severe polyuria and electrolyte imbalance. Homozygous NKCC2-/- pups were born in expected numbers and appeared normal. However, by day 1 they showed signs of extracellular volume depletion (hematocrit 51%; wild type 37%). They subsequently failed to thrive. By day 7, they were small and markedly dehydrated and exhibited renal insufficiency, high plasma potassium, metabolic acidosis, hydronephrosis of varying severity, and high plasma renin concentrations. None survived to weaning. Treatment of -/- pups with indomethacin from day 1 prevented growth retardation and 10% treated for 3 weeks survived, although as adults they exhibited severe polyuria (10 ml/day), extreme hydronephrosis, low plasma potassium, high blood pH, hypercalciuria, and proteinuria. Wild-type mice treated with furosemide, an inhibitor of NaK2Cl cotransporters, have a phenotype similar to the indomethacin-rescued -/- adults except that hydronephrosis was mild. The polyuria, hypercalciuria, and proteinuria of the -/- adults and furosemide-treated wild-type mice were unresponsive to inhibitors of the renin angiotensin system, vasopressin, and further indomethacin. Thus absence of NKCC2 in the mouse causes polyuria that is not compensated elsewhere in the nephron. The NKCC2 mutant animals should be valuable for uncovering new pathophysiologic and therapeutic aspects of genetic disturbances in water and electrolyte recovery by the kidney.
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Affiliation(s)
- N Takahashi
- Department of Pathology and Laboratory Medicine and Division of Nephrology, University of North Carolina, Chapel Hill, NC 27599, USA.
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Watzer B, Reinalter S, Seyberth HW, Schweer H. Determination of free and glucuronide conjugated 20-hydroxyarachidonic acid (20-HETE) in urine by gas chromatography/negative ion chemical ionization mass spectrometry. Prostaglandins Leukot Essent Fatty Acids 2000; 62:175-81. [PMID: 10841040 DOI: 10.1054/plef.2000.0138] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
20-Hydroxy-arachidonic acid (20-HETE) was determined in urine by an isotope dilution assay using gas chromatography/mass spectrometry (GC/MS). After addition of 18O2-internal standard, 20-HETE was extracted from urine with hexane either directly or after treatment with glucuronidase. 20-HETE was derivatized to the pentafluorobenzylester and the sample was applied to thin layer chromatography with iso-octane/iso-propanol 9:1 (v/v) as the developing solvent. The corresponding zone was extracted and 20-HETE was hydrogenated. After derivatization to the trimethylsilylether, 20-HETE was determined by GC/MS using the [M-pentafluorobenzyl]- -ion in the negative ion chemical ionization mode. Excretion rates of free and glucuronide conjugated 20-HETE was determined in healthy children and in children with hyperprostaglandin-E-syndrome/antenatal Bartter syndrome (HPS/aBS) with or without indomethacin treatment. Compared to the controls, the HPS/aBS children showed higher excretion rates of 20-HETE, which were suppressed to normal values under indomethacin medication. Free and glucuronide conjugated 20-HETE do not correlate with PGE2 excluding any participation in HPS/aBS.
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Affiliation(s)
- B Watzer
- Department of Pediatrics, Philipps University Marburg, Germany
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35
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Abstract
Hypophosphatasia (HP) is an inborn error of metabolism that is characterized by reduced bone mineralization. The aim of this investigation was to evaluate treatment of incapacitating lower limb pain in patients with childhood HP using nonsteroidal antiinflammatory drugs (NSAID). All patients (seven boys; age 32 months to 16 years) presented with delayed walking, the typical waddling gait, muscular weakness of the lower limbs, and a limited walking distance. Six patients had severe diffuse lower limb pain following physical activity and were therefore treated with NSAID. The benefit of this treatment was evaluated clinically and by measurement of renally (PGE2) and systemically (PGE-M) derived prostaglandins (PG) in urine before and during therapy. After treatment with NSAID all six patients showed marked clinical improvement with reduced pain, increased muscle strength, and a normalized walking distance. Levels of PGE-M, which had been elevated in four patients prior to therapy, returned to normal. The use of NSAID in childhood HP should be considered as a possible therapeutic approach because the quality of life in these patients is markedly impaired by pain of the limbs. Elevated PG might play a role in the bone metabolism of HP patients.
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Affiliation(s)
- H J Girschick
- Children's Hospital, University of Würzburg, Germany.
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36
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Abstract
Molecular defects affecting the transport of sodium, potassium and chloride in the nephron through the ROMK K+ channel, Na+/K+/2Cl- cotransporter, the Na+/Cl- cotransporter and chloride channel have been identified in patients with Bartter's and Gitelman's syndromes. Defects of the angiotensin II type I receptor and CFTR have also being described. These defects are simple (i.e., most are single amino acid substitutions) but affect key elements in tubular transport. The simplicity of the genetic defects may explain why the inheritance of these conditions remains unclear in most kindreds (i.e., not just recessive or dominant) and emphasises the crucial importance of the conformational structure of these channels. Application of this molecular information will allow the early genetic identification of patients with these syndromes and enable us to differentiate between the various disorders at a functional level. It may also identify a subgroup in which the heterozygous form may make patients potentially exquisitely sensitive to diuretics.
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Affiliation(s)
- S Bhandari
- School of Biomedical Sciences, Department of Physiology, University of Leeds, UK
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37
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Affiliation(s)
- I Kurtz
- UCLA School of Medicine, Los Angeles, California, USA
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38
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Simon DB, Lifton RP. Ion transporter and channel mutations in Bartter's and Gitelman's syndromes of inherited hypokalemic alkalosis. Clin Exp Nephrol 1998. [DOI: 10.1007/bf02480558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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39
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Abstract
Familial hypokalemic, hypochloremic metabolic alkalosis, or Bartter syndrome, is not a single disorder but rather a set of closely related disorders. These Bartter-like syndromes share many of the same physiologic derangements, but differ with regard to the age of onset, the presenting symptoms, the magnitude of urinary potassium (K) and prostaglandin excretion, and the extent of urinary calcium excretion. At least three clinical phenotypes have been distinguished: (1) classic Bartter syndrome; (2) the hypocalciuric-hypomagnesemic Gitelman variant; and (3) the antenatal hypercalciuric variant (also termed hyperprostaglandin E syndrome). The fundamental pathogenesis of this complex set of disorders has long fascinated and stymied investigators. Physiologic investigations have suggested numerous pathogenic models. The cloning of genes encoding renal transport proteins has provided molecular tools to begin testing these hypotheses. To date, molecular genetic analyses have determined that mutations in the gene encoding the thiazide-sensitive sodium-chloride (Na-Cl) cotransporter underlie the pathogenesis of the Gitelman variant. In comparison, the antenatal variant is genetically heterogeneous with mutations in the genes encoding either the bumetanide-sensitive sodium-potassium-chloride (Na-K-2Cl) cotransporter or the luminal, ATP-regulated, K channel. With these data, investigators have begun to unravel the pathophysiologic enigma of the Bartter-like syndromes. Further studies will help refine pathogenic models for this set of disorders as well as provide new insights into the normal mechanisms of renal electrolyte transport.
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Affiliation(s)
- L M Guay-Woodford
- Department of Medicine, University of Alabama at Birmingham, 35294, USA
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40
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Abstract
The successful merging of modern molecular genetics with basic renal physiology is exemplified by the recent description of the molecular basis of two classic diseases of clinical nephrology; Bartter's and Gitelman's syndromes of inherited hypokalemic alkalosis. Mutations in four different genes have been identified, each of which causes hypokalemic alkalosis, salt wasting and hypotension. These genetic studies have greatly advanced our understanding of renal physiology.
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Affiliation(s)
- D B Simon
- Howard Hughes Medical Institute, Department of Medicine, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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41
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Vargas-Poussou R, Feldmann D, Vollmer M, Konrad M, Kelly L, van den Heuvel LP, Tebourbi L, Brandis M, Karolyi L, Hebert SC, Lemmink HH, Deschênes G, Hildebrandt F, Seyberth HW, Guay-Woodford LM, Knoers NV, Antignac C. Novel molecular variants of the Na-K-2Cl cotransporter gene are responsible for antenatal Bartter syndrome. Am J Hum Genet 1998; 62:1332-40. [PMID: 9585600 PMCID: PMC1377151 DOI: 10.1086/301872] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Antenatal Bartter syndrome is a variant of inherited renal-tubular disorders associated with hypokalemic alkalosis. This disorder typically presents as a life-threatening condition beginning in utero, with marked fetal polyuria that leads to polyhydramnios and premature delivery. Another hallmark of this variant is a marked hypercalciuria and, as a secondary consequence, the development of nephrocalcinosis and osteopenia. We have analyzed 15 probands belonging to 13 families and have performed SSCP analysis of the coding sequence and the exon-intron boundaries of the NKCC2 gene; and we report 14 novel mutations in patients with antenatal Bartter syndrome, as well as the identification of three isoforms of human NKCC2 that arise from alternative splicing.
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42
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Abstract
The application of modern techniques in molecular genetics to classic diseases in clinical nephrology is highlighted by the recent description of the molecular basis of Bartter's and Gitelman's syndromes. A series of detailed studies are described that have resulted in the identification of specific mutations in four different genes, each of which causes hypokalemic alkalosis, salt wasting and hypotension. The importance of these genetic studies in understanding renal physiology and the regulation of blood pressure, and in developing new therapeutic strategies is discussed.
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Affiliation(s)
- D B Simon
- Howard Hughes Medical Institute, Department of Medicine (Nephrology), Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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43
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Nüsing RM, Schaub TP, Klein T, Schweer H, Seyberth HW. Prostanoid biosynthesis by blood monocytes of children with hyperprostaglandin E syndrome. Pediatr Res 1997; 42:241-6. [PMID: 9262230 DOI: 10.1203/00006450-199708000-00019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hyperprostaglandin E syndrome (HPS), the prenatal variant of Bartter's syndrome, is characterized by a marked and selective stimulation of prostaglandin E (PGE2) synthesis. In the study group HPS patients showed increased urinary levels of PGE2, an index of renal, and of 11 alpha-hydroxy-9,15-dioxo-2,3,4,5,20-pentanor-19-carboxyprostano ic acid (PGE-M), an index of systemic PGE2 synthesis of 470% and of 570%, respectively. In addition, plasma concentration of PGE-M was also elevated 6.3-fold when compared with a control group. The urinary levels of other prostanoids were unaltered. During indomethacin treatment in both groups prostanoid excretion rates were suppressed to similar levels. To investigate the origin of stimulated prostanoid biosynthesis in HPS patients CD14+ monocytes were isolated from plasma samples, and the prostanoid synthesis was analyzed. The pattern and amounts of metabolites synthesized from endogenous arachidonic acid pools did not vary significantly between monocytes of the HPS and the control group. Thromboxane A2 (TXA2) was formed as the major prostanoid product. Using PGH2 as an exogenous substrate, again no difference in PGE2 biosynthesis was observed, indicating no difference in PGE-synthetic activity between both groups. Additionally, mRNA expression analysis of CD14+ monocytes via RT-PCR delineated the constitutive expression of cyclooxygenase-1, cyclooxygenase-2, and thromboxane synthase mRNA in cells from HPS patients and controls without statistical differences between these two groups. In conclusion, our data show that monocytes are not the source for the increased PGE2 biosynthesis in children with HPS, and a genetic defect in PGE synthesis can be excluded as the primary event in the pathogenesis in HPS.
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Affiliation(s)
- R M Nüsing
- Department of Pediatrics, Philipps University Marburg, Germany
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44
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Károlyi L, Ziegler A, Pollak M, Fischbach M, Grzeschik KH, Koch MC, Seyberth HW. Gitelman's syndrome is genetically distinct from other forms of Bartter's syndrome. Pediatr Nephrol 1996; 10:551-4. [PMID: 8897553 DOI: 10.1007/s004670050158] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the past the term Bartter's syndrome has been used to describe a spectrum of inherited renal tubular disorders with hypokalemic metabolic alkalosis and overlapping and additional clinical and biochemical features. Pathogenesis remained uncertain until recently Gitelman's syndrome, the hypokalemic-hypomagnesemic variant with hypocalciuria, was linked to the gene encoding the thiazide-sensitive Na-Cl-cotransporter (TSC) located on chromosome 16q. Various mutations in the TSC gene were identified in patients with Gitelman's syndrome. To clarify whether different forms of hypokalemic tubular disorders (HTD) represent variable phenotypes of a common genetic defect, we performed linkage analyses in 17 families with different symptoms of HTD with four highly polymorphic chromosome 16 DNA markers closely linked to the TSC gene. Linkage of Gitelman's syndrome to the TSC locus was confirmed in our families with a maximum two-point Lod score Z = 4.70 (theta = 0.001) for marker locus D16S526. Highly negative LOD scores were obtained at this locus in our families with classic Bartter's syndrome (Z = 9.89, theta = 0.001) and hyperprostaglandin E syndrome (Z = -11.24, theta = 0.001). Our data prove that Gitelman's syndrome is genetically distinct from classic Bartter's syndrome and hyperprostaglandin E syndrome. It remains unknown if classic Bartter's syndrome and hyperprostaglandin E syndrome are caused by a common genetic defect.
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Affiliation(s)
- L Károlyi
- Medizinisches Zentrum für Kinderheilkunde, Philipps-Universität, Marburg, Germany
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Lu R, Kanai N, Bao Y, Schuster VL. Cloning, in vitro expression, and tissue distribution of a human prostaglandin transporter cDNA(hPGT). J Clin Invest 1996; 98:1142-9. [PMID: 8787677 PMCID: PMC507536 DOI: 10.1172/jci118897] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We recently identified a cDNA in the rat that encodes a broadly expressed PG transporter (PGT). Because PGs play diverse and important roles in human health and disease, we cloned human PGT (hPGT) from an adult human kidney cDNA library. A consensus sequence (4.0 kb) derived from several clones, plus 3' polymerase chain reaction amplification, exhibited 74% nucleic acid identity and 82% amino acid identity compared to rat PGT. When transiently expressed in HeLa cells, a full-length clone catalyzed the transport of PGE1, PGE2, PGD2, PGF2alpha, and, to a lesser degree, TXB2. Northern blotting revealed mRNA transcripts of many different sizes in adult human heart, placenta, brain, lung, liver, skeletal muscle, pancreas, kidney, spleen, prostate, ovary, small intestine, and colon. hPGT mRNAs are also strongly expressed in human fetal brain, lung, liver, and kidney. The broad tissue distribution and substrate profile of hPGT suggest a role in the transport and/or metabolic clearance of PGs in diverse human tissues.
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Affiliation(s)
- R Lu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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46
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Simon DB, Karet FE, Hamdan JM, DiPietro A, Sanjad SA, Lifton RP. Bartter's syndrome, hypokalaemic alkalosis with hypercalciuria, is caused by mutations in the Na-K-2Cl cotransporter NKCC2. Nat Genet 1996; 13:183-8. [PMID: 8640224 DOI: 10.1038/ng0696-183] [Citation(s) in RCA: 589] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inherited hypokalaemic alkalosis with low blood pressure can be divided into two groups-Gitelman's syndrome, featuring hypocalciuria, hypomagnesaemia and milder clinical manifestations, and Bartter's syndrome, featuring hypercalciuria and early presentation with severe volume depletion. Mutations in the renal Na-Cl cotransporter have been shown to cause Gitelman's syndrome. We demonstrate linkage of Bartter's syndrome to the renal Na-K-2Cl cotransporter gene NKCC2, and identify frameshift or non-conservative missense mutations for this gene that co-segregate with the disease. These findings demonstrate the molecular basis of Bartter's syndrome, provide the basis for molecular classification of patients with inherited hypokalaemic alkalosis, and suggest potential phenotypes in heterozygous carriers of NKCC2 mutations.
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Affiliation(s)
- D B Simon
- Howard Hughes Medical Institute, Department of Medicine, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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47
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Meyburg J, Mayatepek E, Hoffmann GF, Linderkamp O, Seyberth HW. Severe hyperchloriduria-hyperkaliuria: a new congenital renal tubular abnormality? J Pediatr 1996; 128:376-8. [PMID: 8774509 DOI: 10.1016/s0022-3476(96)70286-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A female infant, aged 5 weeks, had metabolic alkalosis associated with severe electrolyte disturbances. In addition to findings typically seen in patients with Bartter syndrome or hyperprostaglandin E syndrome, she had massive urinary excretion of prostaglandins E2 and E-M, normal calcium metabolism, hyperphosphaturia, and severe hyperchloriduria and hyperkaliuria with limited response to indomethacin. These findings may represent a new congenital renal tubular abnormality.
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Affiliation(s)
- J Meyburg
- University Children's Hospital, Heidelberg, Germany
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48
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Abstract
Pre-pubertal body growth was followed in eight children with the hyperprostaglandin E syndrome (neonatal Bartter syndrome) treated with indomethacin over a period of 5-12 years. When corrected for prematurity, the general growth pattern was normal, with the exception of a child with delayed therapy. From the first observation (usually at birth) to the start of indomethacin, the mean height standard deviation score (SDS) corrected for prematurity changed from -0.2 to -2.8. During the first 2 years of therapy rapid catch-up growth occurred, followed by a slow adaptation of the growth pattern to that of healthy children born at term. At last observation the mean corrected height SDS was -0.5 (range -1.9 to +0.9) and the mean target height -0.9 SDS (range -1.8 to +0.1). Weight, body mass index and bone maturation also reached the normal range. No correlation was found between height SDS per year and serum potassium levels or calcium excretion. We conclude that under indomethacin treatment long-term skeletal growth of children with the hyperprostaglandin E syndrome is similar to that of other preterm children.
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Affiliation(s)
- C Seidel
- University Children's Hospital, Heidelberg, Germany
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49
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Abstract
Bartter's syndrome is a congenital abnormality characterized by metabolic alkalosis [corrected], hyperreninemic hyperaldosteronism, and hypokalemia. Most patients present early in life with symptoms such as muscle weakness and polyuria, which may be attributed to potassium depletion. Despite the hyperaldosteronism, the patients tend to be normotensive, which is at least partially explained by vascular hyporesponsiveness to pressor hormones. Numerous studies have documented increased renal excretion of prostaglandins. Several different patterns of aberrant renal ion transport have been observed in patients with the syndrome, suggesting that it actually may represent a family of related but distinct tubular disorders. Therapeutic approaches to Bartter's syndrome include potassium supplementation, prostaglandin synthesis inhibitors (nonsteroidal anti-inflammatory agents), aldosterone antagonists, and converting enzyme inhibitors. During the first two decades following its initial description, Bartter's syndrome was the focus of widespread interest, based on the likelihood that its investigation might provide insight into the normal functioning of the renin-angiotensin-aldosterone and prostanoid hormone systems. During the past decade, however, little additional progress has been made in Bartter's syndrome, and its patho-physiology remains poorly understood.
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Affiliation(s)
- D M Clive
- Department of Medicine, University of Massachusetts Medical Center, Worcester 01655, USA
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50
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Abstract
The role of eicosanoids, arachidonic acid (AA) metabolites, in blood pressure regulation under physiological and pathological conditions during the perinatal period is still under investigation. This review focuses on the synthesis and catabolism of some vasoactive AA metabolites by fetal, neonatal and placental cells, and on the vascular responses of the fetus and neonate to prostanoids and to the inhibitors of their synthesis. Vasodilator prostaglandins, PGE2 and prostacyclin (PGI2), increase steadily during pregnancy, while thromboxane A2 (TXA2), a potent vasoconstrictor, remains low during pregnancy, increasing only shortly before delivery. TXA2 participates in the closure of umbilical vessels and ductus arteriosus. In pregnancy-induced hypertension, increase in the synthesis of TXA2 occurs early during pregnancy. Decrease in the catabolism of AA precedes the onset of hypertension in the developing spontaneously hypertensive rat. In newborn piglets, platelet-activating factor, vasoconstrictor porstaglandins and leukotriene D4 have a marked constrictor effect on the pulmonary circulation and induce pulmonary hypertension, without affecting the systemic blood pressure. Although the role of AA metabolites in the regulation of haemodynamics during the perinatal period is not fully understood, it is apparent that several eicosanoids modulate the action of hormones and vasoactive agents.
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Affiliation(s)
- J L Reyes
- Department of Physiology and Biophysics, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México, D.F
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