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Gankam Kengne F. Adaptation of the Brain to Hyponatremia and Its Clinical Implications. J Clin Med 2023; 12:jcm12051714. [PMID: 36902500 PMCID: PMC10002753 DOI: 10.3390/jcm12051714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/12/2023] [Accepted: 02/17/2023] [Indexed: 02/25/2023] Open
Abstract
Hyponatremia is the most common electrolyte disorder, occurring in up to 25% of hospitalized patients. Hypo-osmotic hyponatremia when severe and left untreated invariably results in cell swelling, which can lead to fatal consequences, especially in the central nervous system. The brain is particularly vulnerable to the consequences of decreased extracellular osmolarity; because of being encased in the rigid skull, it cannot withstand persistent swelling. Moreover, serum sodium is the major determinant of extracellular ionic balance, which in turn governs crucial brain functions such as the excitability of neurons. For these reasons, the human brain has developed specific ways to adapt to hyponatremia and prevent brain edema. On the other hand, it is well known that rapid correction of chronic and severe hyponatremia can lead to brain demyelination, a condition known as osmotic demyelination syndrome. In this paper, we will discuss the mechanisms of brain adaptation to acute and chronic hyponatremia and the neurological symptoms of these conditions as well as the pathophysiology and prevention of osmotic demyelination syndrome.
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Lee JH, Kim CS, Bae EH, Kim SW, Ma SK. Osmotic Demyelination Syndrome Associated with Hypernatremia Caused by Lactulose Enema in a Patient with Chronic Alcoholism. Electrolyte Blood Press 2021; 19:15-18. [PMID: 34290820 PMCID: PMC8267071 DOI: 10.5049/ebp.2021.19.1.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/03/2022] Open
Abstract
A 44-year-old man with chronic alcoholism presented with seizure and loss of consciousness. He was diagnosed with alcoholic hepatic encephalopathy, and his neurologic symptoms recovered after lactulose enema treatment. His initial serum sodium level was 141mEq/L. However, his mental state became confused after treatment with lactulose enema for five days, and his serum sodium level increased to 178mEq/L. After five days of gradual correction of serum sodium level from 178mEq/L to 140mEq/L, the patient's mental state recovered, but motor weakness in both limbs remained. Therefore, magnetic resonance imaging of the brain was performed. T2-weighted brain images showed bilateral symmetrical hyperintensities in the central pons, basal ganglia, thalami, hippocampi and unci, which were consistent with central pontine and extrapontine myelinolysis. We report a rare case of osmotic demyelination syndrome that occurred as a result of a rapid increase from a normal sodium level to hypernatremia caused by lactulose enema administered to treat alcoholic hepatic encephalopathy.
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Affiliation(s)
- Jeong Ho Lee
- Department of Internal Medicine, Gwangju Veterans Hospital, Gwangju, Republic of Korea
| | - Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Seong Kwon Ma
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
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3
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Scalisi J, Balau B, Deneyer L, Bouchat J, Gilloteaux J, Nicaise C. Blood-brain barrier permeability towards small and large tracers in a mouse model of osmotic demyelination syndrome. Neurosci Lett 2021; 746:135665. [DOI: 10.1016/j.neulet.2021.135665] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/17/2020] [Accepted: 01/13/2021] [Indexed: 01/01/2023]
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Gargano G, Manfredi M, Pedori S, Di Dio F, Spagnoli C, Frattini D. A highly unusual case of osmotic demyelination syndrome and extrapontine myelinolysis in a 3-month-old infant with Bartter syndrome. J Int Med Res 2020; 48:300060520966494. [PMID: 33107776 PMCID: PMC7645388 DOI: 10.1177/0300060520966494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Bartter syndrome (BS) is a rare autosomal recessive renal tubular disorder characterized by acute electrolyte imbalance, and similarly, osmotic demyelination syndrome (ODS) is a rather rare complication occurring during electrolyte imbalance. The pathological features of ODS include central pontine myelinolysis and extrapontine myelinolysis (EPM), which consist of severe damage to the myelin sheath of neurons. ODS is very rare in children. We describe a case of a 3-month-old infant with ODS and EPM associated with undiagnosed BS. ODS developed because of a sudden change in electrolyte levels and osmolality caused by acute dehydration during a gastrointestinal infection episode. Undiagnosed, untreated, and non-balanced BS was the cause of the neurological complication. Our patient represents the first case of ODS in BS, the ninth case of ODS in an infant less than one year old, and the third case of isolated EPM in such a young patient. This case report reminds us that in rare diseases, young patients tend to have genetic components.
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Affiliation(s)
- Giancarlo Gargano
- Neonatal Intensive Care Unit (NICU), Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Marco Manfredi
- Pediatric Unit, Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Sant'Anna Hospital, Castelnovo Monti, Italy
| | - Simona Pedori
- Neonatal Intensive Care Unit (NICU), Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Francesco Di Dio
- Neonatal Intensive Care Unit (NICU), Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Carlotta Spagnoli
- Child Neuropsychiatry, Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Daniele Frattini
- Child Neuropsychiatry, Obstetric and Pediatric Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
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Nelson NR, Tompkins MG, Thompson Bastin ML. Plasma exchange as treatment for osmotic demyelination syndrome: Case report and review of current literature. Transfus Apher Sci 2019; 58:102663. [PMID: 31759898 DOI: 10.1016/j.transci.2019.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/12/2019] [Accepted: 10/15/2019] [Indexed: 10/25/2022]
Abstract
Osmotic demyelination syndrome (ODS) is characterized by widespread degeneration of myelin within the central nervous system and has no established treatment. A limited number of cases have reported positive outcomes with plasma exchange in the treatment of ODS associated with chronic alcohol abuse or liver transplantation. We report the case of a 23-year-old female presenting with ODS following rapid correction of hyponatremia, which was attributed to hypoalbuminemia, volume overload, and malnutrition secondary to ulcerative colitis. Our patient received four plasma exchange sessions over the course of five days for a total plasma exchange of 15,500 mL. Unfortunately, the patient did not achieve significant neurologic recovery following completion of the plasma exchange regimen. This is the first report of the failure of this novel approach in the management of a patient with ODS, suggesting benefit in a limited patient population. We describe the proposed mechanism of plasma exchange in the treatment of ODS and provide a review of existing literature.
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Affiliation(s)
- Nicholas R Nelson
- University of Kentucky HealthCare, Department of Pharmacy Services, United States.
| | - Madeline G Tompkins
- University of Kentucky College of Pharmacy, Department of Pharmacy Practice and Science, United States
| | - Melissa L Thompson Bastin
- University of Kentucky HealthCare, Department of Pharmacy Services, United States; University of Kentucky College of Pharmacy, Department of Pharmacy Practice and Science, United States.
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Nicaise C, Marneffe C, Bouchat J, Gilloteaux J. Osmotic Demyelination: From an Oligodendrocyte to an Astrocyte Perspective. Int J Mol Sci 2019; 20:E1124. [PMID: 30841618 PMCID: PMC6429405 DOI: 10.3390/ijms20051124] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/15/2022] Open
Abstract
Osmotic demyelination syndrome (ODS) is a disorder of the central myelin that is often associated with a precipitous rise of serum sodium. Remarkably, while the myelin and oligodendrocytes of specific brain areas degenerate during the disease, neighboring neurons and axons appear unspoiled, and neuroinflammation appears only once demyelination is well established. In addition to blood‒brain barrier breakdown and microglia activation, astrocyte death is among one of the earliest events during ODS pathology. This review will focus on various aspects of biochemical, molecular and cellular aspects of oligodendrocyte and astrocyte changes in ODS-susceptible brain regions, with an emphasis on the crosstalk between those two glial cells. Emerging evidence pointing to the initiating role of astrocytes in region-specific degeneration are discussed.
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Affiliation(s)
| | - Catherine Marneffe
- Laboratory of Glia Biology (VIB-KU Leuven Center for Brain & Disease Research), Department of Neuroscience, KU Leuven, 3000 Leuven, Belgium.
| | - Joanna Bouchat
- URPhyM-NARILIS, Université de Namur, 5000 Namur, Belgium.
| | - Jacques Gilloteaux
- URPhyM-NARILIS, Université de Namur, 5000 Namur, Belgium.
- Department of Anatomical Sciences, St George's University School of Medicine, Newcastle upon Tyne NE1 8ST, UK.
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Sheikh AB, Afzal RM, Sagheer S, Bukhari MM, Javed A, Nasrullah A, Tariq U, Athar F, Saleem MS. The Dilemma of Inadvertent Pontine Demyelinosis: A Review of Literature. Cureus 2018; 10:e3174. [PMID: 30357070 PMCID: PMC6197531 DOI: 10.7759/cureus.3174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Osmotic demyelination syndrome is classically associated with a swift adjustment of previously low serum sodium levels which lead to cellular dehydration and subsequent neurological insult. We also review the epidemiology, different postulations to explain the underlying pathophysiology, current diagnostic modalities, subsequent therapeutic interventions used to manage this phenomenon, and the resultant prognosis of this ailment.
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Affiliation(s)
| | - Rao M Afzal
- Internal Medicine, Shifa College of Medicine, Islamabad, PAK
| | - Shazib Sagheer
- Internal Medicine, University of New Mexico Hospital, Albuquerque, USA
| | - Marvi M Bukhari
- Internal Medicine, Shifa College of Medicine, Islamabad, PAK
| | - Anam Javed
- Internal Medicine, College of Medicine and Dentistry, University of Lahore, Lahore, PAK
| | - Adeel Nasrullah
- Internal Medicine, Allegheny General Hospital, Pittsburgh, USA
| | - Usman Tariq
- Research Assistant, Yale University School of Medicine, New Haven, USA
| | - Fahad Athar
- Other, Albert Einstein Medical Center , Philadelphia, USA
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Hsu YC, Lee YC, Hsu CW. Osmotic demyelination syndrome after slow sodium administration in a hyponatremic patient with concurrent hypokalemia. Am J Emerg Med 2017; 35:378.e3-378.e4. [DOI: 10.1016/j.ajem.2016.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 08/11/2016] [Indexed: 10/21/2022] Open
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Kleindienst A, Hannon MJ, Buchfelder M, Verbalis JG. Hyponatremia in Neurotrauma: The Role of Vasopressin. J Neurotrauma 2015; 33:615-24. [PMID: 26472056 DOI: 10.1089/neu.2015.3981] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Hyponatremia is frequent in patients suffering from traumatic brain injury, subarachnoid hemorrhage, or following intracranial procedures, with approximately 20% having a decreased serum sodium concentration to <125 mmol/L. The pathophysiology of hyponatremia in neurotrauma is not completely understood, but in large part is explained by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The abnormal water and/or sodium handling creates an osmotic gradient promoting the shift of water into brain cells, thereby worsening cerebral edema and precipitating neurological deterioration. Unless hyponatremia is corrected promptly and effectively, morbidity and mortality increases through seizures, elevations in intracranial pressure, and/or herniation. The excess mortality in patients with severe hyponatremia (<125 mmol/L) extends beyond the time frame of hospital admission, with a reported mortality of 20% in hospital and 45% within 6 months of follow-up. Current options for the management of hyponatremia include fluid restriction, hypertonic saline, mineralocorticoids, and osmotic diuretics. However, the recent development of vasopressin receptor antagonists provides a more physiological tool for the management of excess water retention and consequent hyponatremia, such as occurs in SIADH. This review summarizes the existing literature on the pathophysiology, clinical features, and management of hyponatremia in the setting of neurotrauma.
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Affiliation(s)
- Andrea Kleindienst
- 1 Department of Neurosurgery, Friedrich-Alexander-University Erlangen-Nürenberg , Erlangen, Germany .,2 Department of Neurosurgery, Klinikum Amberg, Amberg, Germany
| | | | - Michael Buchfelder
- 1 Department of Neurosurgery, Friedrich-Alexander-University Erlangen-Nürenberg , Erlangen, Germany
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Laville M, Burst V, Peri A, Verbalis JG. Hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH): therapeutic decision-making in real-life cases. Clin Kidney J 2015; 6:i1-i20. [PMID: 26069838 PMCID: PMC4438352 DOI: 10.1093/ckj/sft113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite being the most common electrolyte disturbance encountered in clinical practice, the diagnosis and treatment of hyponatremia (defined as a serum sodium concentration <135 mmol/L) remains far from optimal. This is extremely troubling because not only is hyponatremia associated with increased morbidity, length of hospital stay and hospital resource use, but it has also been shown to be associated with increased mortality. The reasons for this poor management may partly lie in the heterogeneous nature of the disorder; hyponatremia presents with a variety of possible etiologies, differing symptomology and fluid volume status, thereby making its diagnosis potentially complex. In addition, a general lack of awareness of the clinical impact of the disorder, a fear of adverse outcomes through overcorrection of sodium levels, and a lack of effective targeted treatments until recent years, may all have contributed to a reticence to actively treat cases of hyponatremia. There is therefore a clear unmet need to further educate physicians on the pathophysiology, diagnosis and management of this important condition. Through the use of a variety of real-world cases of patients with hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone—a condition that accounts for approximately one-third of all cases of hyponatremia—this supplement aims to provide a comprehensive overview of the challenges faced in diagnosing and managing hyponatremia. These cases will also help to illustrate how some of the limitations of traditional therapies may be overcome with the use of vasopressin receptor antagonists.
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Affiliation(s)
- Maurice Laville
- Renal Unit , Lyon-Sud Hospital , Pierre-Bénite 69495 , France ; INSERM U1060, CarMeN Institute , University of Lyon , Lyon , France
| | - Volker Burst
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany
| | - Alessandro Peri
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences , University of Florence , Florence , Italy
| | - Joseph G Verbalis
- Division of Endocrinology and Metabolism, Department of Medicine , Georgetown University Medical Center , Washington, DC 20007 , USA
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Gankam Kengne F, Couturier BS, Soupart A, Decaux G. Urea minimizes brain complications following rapid correction of chronic hyponatremia compared with vasopressin antagonist or hypertonic saline. Kidney Int 2014; 87:323-31. [PMID: 25100046 DOI: 10.1038/ki.2014.273] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 06/12/2014] [Accepted: 06/13/2014] [Indexed: 01/04/2023]
Abstract
Hyponatremia is a common electrolyte disorder that carries significant morbidity and mortality. However, severe chronic hyponatremia should not be corrected rapidly to avoid brain demyelination. Vasopressin receptor antagonists (vaptans) are now being widely used for the treatment of hyponatremia along with other alternatives like hypertonic saline. Previous reports have suggested that, in some cases, urea can also be used to correct hyponatremia. Correction of severe hyponatremia with urea has never been compared to treatment with a vaptan or hypertonic saline with regard to the risk of brain complications in the event of a too rapid rise in serum sodium. Here, we compared the neurological outcome of hyponatremic rats corrected rapidly with urea, lixivaptan, and hypertonic saline. Despite similar increase in serum sodium obtained by the three drugs, treatment with lixivaptan or hypertonic saline resulted in a higher mortality than treatment with urea. Histological analysis showed that treatment with urea resulted in less pathological change of experimental osmotic demyelination than was induced by hypertonic saline or lixivaptan. This included breakdown of the blood-brain barrier, microglial activation, astrocyte demise, and demyelination. Thus, overcorrection of hyponatremia with urea resulted in significantly lower mortality and neurological impairment than the overcorrection caused by lixivaptan or hypertonic saline.
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Affiliation(s)
- Fabrice Gankam Kengne
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Bruno S Couturier
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Alain Soupart
- 1] Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium [2] Hopital de Tubize, Department of Internal Medicine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Guy Decaux
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
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Ahmed A, Tschetter PA, Krasowski MD, Engelman A. Massive Ethylene Glycol Poisoning Triggers Osmotic Demyelination Syndrome. J Emerg Med 2014; 46:e69-74. [DOI: 10.1016/j.jemermed.2013.08.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/02/2013] [Accepted: 08/15/2013] [Indexed: 11/30/2022]
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Sterns RH, Silver S, Kleinschmidt-DeMasters BK, Rojiani AM. Current perspectives in the management of hyponatremia: prevention of CPM. Expert Rev Neurother 2014; 7:1791-7. [DOI: 10.1586/14737175.7.12.1791] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kim YS, Lee J, Baek W, Lee YJ, Kim HY. Pontine hemorrhage at a microbleed site in a patient with central pontine myelinolysis. Neurol Sci 2011; 32:1251-2. [PMID: 21938466 DOI: 10.1007/s10072-011-0783-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 09/08/2011] [Indexed: 11/29/2022]
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Affiliation(s)
- Jeffrey C Sirota
- University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA
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Galton C, Deem S, Yanez ND, Souter M, Chesnut R, Dagal A, Treggiari M. Open-Label Randomized Trial of the Safety and Efficacy of a Single Dose Conivaptan to Raise Serum Sodium in Patients with Traumatic Brain Injury. Neurocrit Care 2011; 14:354-60. [DOI: 10.1007/s12028-011-9525-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Iwama S, Sugimura Y, Suzuki H, Suzuki H, Murase T, Ozaki N, Nagasaki H, Arima H, Murata Y, Sawada M, Oiso Y. Time-dependent changes in proinflammatory and neurotrophic responses of microglia and astrocytes in a rat model of osmotic demyelination syndrome. Glia 2010; 59:452-62. [PMID: 21264951 DOI: 10.1002/glia.21114] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 10/29/2010] [Indexed: 01/27/2023]
Abstract
Osmotic demyelination syndrome (ODS) is a serious demyelinating disease in the central nervous system usually caused by rapid correction of hyponatremia. In an animal model of ODS, we previously reported microglial accumulation expressing proinflammatory cytokines. Microglia and astrocytes secreting proinflammatory cytokines and neurotrophic factors are reported to be involved in the pathogenesis of demyelinative diseases. Therefore, to clarify the role of microglial and astrocytic function in ODS, we examined the time-dependent changes in distribution, morphology, proliferation, and mRNA/protein expression of proinflammatory cytokines, neurotrophic factors, and matrix metalloproteinase (MMP) in microglia and astrocytes 2 days (early phase) and 5 days (late phase) after the rapid correction of hyponatremia in ODS rats. The number of microglia time dependently increased at demyelinative lesion sites, proliferated, and expressed tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, inducible nitric oxide synthase, and MMP2, 9, and 12 at the early phase. Microglia also expressed leukemia inhibitory factor (a neurotrophic factor) and phagocytosed myelin debris at the late phase. The number of astrocytes time dependently increased around demyelinative lesions, extended processes to lesions, proliferated, and expressed nerve growth factor and glial cell line-derived neurotrophic factor at the late phase. Moreover, treatment with infliximab, a monoclonal antibody against TNF-α, significantly attenuated neurological impairments. Our results suggest that the role of microglia in ODS is time dependently shifted from detrimental to protective and that astrocytes play a protective role at the late phase. Modulation of excessive proinflammatory responses in microglia during the early phase after rapid correction may represent a therapeutic target for ODS.
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Affiliation(s)
- Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Gankam-Kengne F, Soupart A, Pochet R, Brion JP, Decaux G. Minocycline protects against neurologic complications of rapid correction of hyponatremia. J Am Soc Nephrol 2010; 21:2099-108. [PMID: 21051736 DOI: 10.1681/asn.2010050467] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Osmotic demyelination syndrome is a devastating neurologic condition that occurs after rapid correction of serum sodium in patients with hyponatremia. Pathologic features of this injury include a well-demarcated region of myelin loss, a breakdown of the blood-brain barrier, and infiltration of microglia. The semisynthetic tetracycline minocycline is protective in some animal models of central nervous system injury, including demyelination, suggesting that it may also protect against demyelination resulting from rapid correction of chronic hyponatremia. Using a rat model of osmotic demyelination syndrome, we found that treatment with minocycline significantly decreases brain demyelination, alleviates neurologic manifestations, and reduces mortality associated with rapid correction of hyponatremia. Mechanistically, minocycline decreased the permeability of the blood-brain barrier, inhibited microglial activation, decreased both the expression of IL1α and protein nitrosylation, and reduced the loss of GFAP immunoreactivity. In conclusion, minocycline modifies the course of osmotic demyelination in rats, suggesting its possible therapeutic use in the setting of inadvertent rapid correction of chronic hyponatremia in humans.
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Affiliation(s)
- Fabrice Gankam-Kengne
- Research Unit on Hydromineral Metabolism, Erasme University Hospital, Brussels, Belgium.
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New aspects in the pathogenesis, prevention, and treatment of hyponatremic encephalopathy in children. Pediatr Nephrol 2010; 25:1225-38. [PMID: 19894066 PMCID: PMC2874061 DOI: 10.1007/s00467-009-1323-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 08/17/2009] [Accepted: 08/27/2009] [Indexed: 12/28/2022]
Abstract
Hyponatremia is the most common electrolyte abnormality encountered in children. In the past decade, new advances have been made in understanding the pathogenesis of hyponatremic encephalopathy and in its prevention and treatment. Recent data have determined that hyponatremia is a more serious condition than previously believed. It is a major comorbidity factor for a variety of illnesses, and subtle neurological findings are common. It has now become apparent that the majority of hospital-acquired hyponatremia in children is iatrogenic and due in large part to the administration of hypotonic fluids to patients with elevated arginine vasopressin levels. Recent prospective studies have demonstrated that administration of 0.9% sodium chloride in maintenance fluids can prevent the development of hyponatremia. Risk factors, such as hypoxia and central nervous system (CNS) involvement, have been identified for the development of hyponatremic encephalopathy, which can lead to neurologic injury at mildly hyponatremic values. It has also become apparent that both children and adult patients are dying from symptomatic hyponatremia due to inadequate therapy. We have proposed the use of intermittent intravenous bolus therapy with 3% sodium chloride, 2 cc/kg with a maximum of 100 cc, to rapidly reverse CNS symptoms and at the same time avoid the possibility of overcorrection of hyponatremia. In this review, we discuss how to recognize patients at risk for inadvertent overcorrection of hyponatremia and what measures should taken to prevent this, including the judicious use of 1-desamino-8d-arginine vasopressin (dDAVP).
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Abstract
The osmotic demyelination syndrome (ODS) has been a recognized complication of the rapid correction of hyponatremia for decades. However, in recent years, a variety of other medical conditions have been associated with the development of ODS, independent of changes in serum sodium. This finding suggests that the pathogenesis of ODS may be more complex and involve the inability of brain cells to respond to rapid changes in osmolality of the interstitial (extracellular) compartment of the brain, leading to dehydration of energy-depleted cells with subsequent axonal damage that occurs in characteristic areas. Features of the syndrome include quadriparesis and neurocognitive changes in the presence of characteristic lesions found on magnetic resonance imaging of the brain. Although slow correction of hyponatremia seems to be the best way to prevent development of the syndrome, there are new data that suggest reintroduction of hyponatremia in those patients who have undergone inadvertent rapid correction of the serum sodium and corticosteroids may play a role in prevention of ODS.
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Norenberg MD. Central pontine myelinolysis: historical and mechanistic considerations. Metab Brain Dis 2010; 25:97-106. [PMID: 20182780 DOI: 10.1007/s11011-010-9175-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 01/28/2010] [Indexed: 02/06/2023]
Abstract
Central pontine myelinolysis (CPM) is a demyelinating condition affecting not only the pontine base, but also involving other brain areas. It usually occurs on a background of chronic systemic illness, and is commonly observed in individuals with alcoholism, malnutrition and liver disease. Studies carried out 25-30 years ago established that the principal etiological factor was the rapid correction of hyponatremia resulting in osmotic stress. This article reviews progress achieved since that time on its pathogenesis, focusing on the role of organic osmolytes, the blood-brain, barrier, endothelial cells, myelinotoxic factors triggered by osmotic stress, and the role of various factors that predispose to the development of CPM. These advances show great promise in providing novel therapeutic options for the management of patients afflicted with CPM.
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Affiliation(s)
- Michael D Norenberg
- Departments of Pathology, University of Miami School of Medicine, PO Box 016960, Miami, FL 33101, USA.
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22
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Abstract
Overcorrection of hyponatremia is a medical emergency. Excessive correction usually results from the unexpected emergence of a water diuresis after resolution of the cause of water retention. The concurrent administration of desmopressin and 5% dextrose in water can be given to cautiously re-lower the serum sodium concentration when therapeutic limits have been exceeded. Nephrologists should be equally aggressive in correcting hyponatremia and in un-correcting it when their patients get too much of a good thing.
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23
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Re-induction of hyponatremia after rapid overcorrection of hyponatremia reduces mortality in rats. Kidney Int 2009; 76:614-21. [DOI: 10.1038/ki.2009.254] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Selective tonicity-induced expression of the neutral amino-acid transporter SNAT2 in oligodendrocytes in rat brain following systemic hypertonicity. Neuroscience 2008; 153:95-107. [DOI: 10.1016/j.neuroscience.2008.01.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 12/20/2007] [Accepted: 01/18/2008] [Indexed: 12/22/2022]
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26
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Abstract
Central pontine myelinolysis (CPM) is a rare but serious demyelinative disease that is associated with rapid correction of chronic hyponatremia. Disruption of the blood-brain barrier (BBB) following a rapid increase in serum sodium concentration is considered to play a critical role in the pathogenesis of osmotic demyelination. We investigated the protective effect of dexamethasone (DEX) on osmotic demyelination in rats. After rapid correction of chronic hyponatremia, rats displayed serious neurologic impairments and demyelinative lesions were observed in various brain regions. Conversely, DEX-treated rats exhibited minimal neurologic impairments and demyelinative lesions were rarely seen in the brain. A marked extravasation of endogenous immunoglobulin G and Evans blue dye were observed in the brains of rats that did not receive DEX, indicating disruption of the BBB, but this was not observed in DEX-treated rats. These results indicate that DEX is effective in preventing osmotic demyelination by inhibiting BBB disruption, and suggest that DEX might be useful for the prevention of CPM in clinical practice.
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Affiliation(s)
- Takashi Murase
- Department of Teratology and Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
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27
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Abstract
Hyponatremia exerts most of its clinical effects on the brain. An acute onset (usually in <24 hours) of hyponatremia causes severe, and sometimes fatal, cerebral edema. Given time, the brain adapts to hyponatremia, permitting survival despite extraordinarily low serum sodium concentrations. Adaptation to severe hyponatremia is critically dependent on the loss of organic osmolytes from brain cells. These intracellular, osmotically active solutes contribute substantially to the osmolality of cell water and do not adversely affect cell functions when their concentration changes. The adaptation that permits survival in patients with severe, chronic (>48 hours' duration) hyponatremia also makes the brain vulnerable to injury (osmotic demyelination) if the electrolyte disturbance is corrected too rapidly. The reuptake of organic osmolytes after correction of hyponatremia is slower than the loss of organic osmolytes during the adaptation to hyponatremia. Areas of the brain that remain most depleted of organic osmolytes are the most severely injured by rapid correction. The brain's reuptake of myoinositol, one of the most abundant osmolytes, occurs much more rapidly in a uremic environment, and patients with uremia are less susceptible to osmotic demyelination. In an experimental model of chronic hyponatremia, exogenous administration of myoinositol speeds the brain's reuptake of the osmolyte and reduces osmotic demyelination and mortality caused by rapid correction.
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Affiliation(s)
- Richard H Sterns
- Department of Medicine, Rochester General Hospital, University of Rochester School of Medicine and Dentistry, Rochester, New York 14621, USA.
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Sugimura Y, Murase T, Takefuji S, Hayasaka S, Takagishi Y, Oiso Y, Murata Y. Protective effect of dexamethasone on osmotic-induced demyelination in rats. Exp Neurol 2005; 192:178-83. [PMID: 15698632 DOI: 10.1016/j.expneurol.2004.10.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 10/08/2004] [Accepted: 10/20/2004] [Indexed: 12/17/2022]
Abstract
Central pontine myelinolysis (CPM) is a serious demyelination disease commonly associated with the rapid correction of hyponatremia. Although its pathogenesis remains unclear, the disruption of the blood-brain barrier (BBB) as a consequence of a rapid increase in serum sodium concentration is considered to play a critical role. Since glucocorticoids are known to influence BBB permeability and prevent its disruption as a result of hypertension or hyperosmolarity, we investigated whether dexamethasone (DEX) could protect against osmotic demyelination in an animal model of CPM. Hyponatremia was induced in rats by liquid diet feeding and dDAVP infusion. Seven days later, the animals' hyponatremia was rapidly corrected by injecting a bolus of hypertonic saline intraperitoneally. Rats subjected to this treatment displayed serious neurological impairment and 77% died within 5 days of rapid correction of their hyponatremia; demyelinative lesions were observed in various brain regions in these animals. On the other hand, rats that were treated with DEX (2 mg/kg, 0 and 6 h after hypertonic saline injection) exhibited minimal neurological impairment and all were alive after 5 days. Demyelinative lesions were rarely seen in the brains of DEX-treated rats. A marked extravasation of endogenous IgG was observed in the demyelinative lesions in the brains of rats that did not receive DEX, indicating disruption of the BBB, but was not observed in DEX-treated rats. Furthermore, Evans blue injection revealed a significant reduction in staining in the brains of DEX-treated rats (P < 0.05). These results indicate that early DEX treatment can prevent the BBB disruption that is caused by the rapid correction of hyponatremia and its associative demyelinative changes, and suggest that DEX might be effective in preventing CPM.
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Affiliation(s)
- Yoshihisa Sugimura
- Department of Teratology and Genetics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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29
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Oztaş B, Kaya M, Küçük M, Tuğran N. Influence of hypoosmolality on the blood-brain barrier permeability during epileptic seizures. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:701-4. [PMID: 12787859 DOI: 10.1016/s0278-5846(03)00084-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Changes in the blood-brain barrier permeability to macromolecules were investigated during pentylenetetrazol-induced seizures, using Evans-blue as an indicator, in water-intoxicated and nonintoxicated Wistar albino (210-250 g) adult rats of both sexes. Evans-blue albumin extravasation was judged visually and estimated quantitatively with a spectrophotometer using homogenized brain to release the dye. Hypoosmolar treatment (water intoxication) was performed by the intraperitoneal administration of distilled water to a volume of 10% of the body weight; Six groups of rats were studied. Group I: female control (n=10), Group II: male control (n=10), Group III: nonwater-intoxicated female+seizure (n=15), Group IV: nonwater-intoxicated male+seizure (n=15), Group V: water-intoxicated female+seizure (n=15), Group VI: water-intoxicated male+seizure (n=15). Approximately 2 h after the injection of water, the plasma osmolarity had decreased by 25-30 mosm. Our results revealed that in female rats, the extravasation of Evans-blue albumin was greater in the brains of water-intoxicated rats compared to nonwater-intoxicated rats after pentylenetetrazol-induced seizures. In addition, hypoosmotic female rats were shown to have a larger increase in blood-brain barrier permeability than hypoosmotic male rats after pentylenetetrazol-induced seizures. This difference between male and female rats was found to be significant (P=.005).
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Affiliation(s)
- Baria Oztaş
- Istanbul Faculty of Medicine, Department of Physiology, Istanbul University, Capa 34 390, Istanbul, Turkey.
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30
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Janicic N, Verbalis JG. Evaluation and management of hypo-osmolality in hospitalized patients. Endocrinol Metab Clin North Am 2003; 32:459-81, vii. [PMID: 12800541 DOI: 10.1016/s0889-8529(03)00004-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hyponatremia is the most common electrolyte disorder encountered in the clinical setting. Abnormalities of the mechanisms that maintain normal water and sodium metabolism are often present in hospitalized patients, including defects in renal water excretion. All of the current therapeutic approaches in patients with the syndrome of inappropriate antidiuretic hormone secretion and other forms of vasopressin-induced hyponatremia have significant limitations. Studies in animal models and humans have demonstrated that antagonists of the AVP V2 receptor in the kidney are effective in correcting hyponatremia. These new agents have been termed "aquaretics" because of their ability to induce a free water diuresis without the natriuresis or kaliuresis characteristic of diuretic drugs. When approved for clinical use, selective V2, and possibly also combined V1 + V2 receptor antagonists will be helpful in therapy.
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Affiliation(s)
- Natasa Janicic
- Division of Endocrinology and Metabolism, Georgetown University Medical Center, 232 Building D, 4000 Reservoir Road NW, Washington, DC 20007, USA
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31
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Silver SM, Schroeder BM, Sterns RH. Brain uptake of myoinositol after exogenous administration. J Am Soc Nephrol 2002; 13:1255-1260. [PMID: 11961013 DOI: 10.1681/asn.v1351255] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
An acute increase in plasma tonicity results in an adaptive increase in brain organic osmolyte content, but this process requires several days to occur. Slow reaccumulation of brain organic osmolytes may contribute to osmotic demyelination. It was investigated whether administration of intravenous myoinositol in rats could speed entry of the osmolyte into the brain. Two groups of animals were studied: normonatremic animals and animals with hyponatremia (105 mmol/L) of 3-d duration. Animals were intravenously administered either 1 M NaCl to induce a 25 to 28 mM increase in serum sodium concentration over 200 min or an infusate that maintained serum sodium concentration. In some animals, myoinositol was administered intravenously over the same time period to raise plasma myoinositol levels by 5 to 10 mM. Brain myoinositol, electrolyte, and water contents were determined at the end of the infusions. In both normonatremic and hyponatremic rats, infusion of hypertonic saline without myoinositol or infusion of myoinositol without hypertonic saline did not increase brain myoinositol levels above control levels. In normonatremic animals, concurrent infusion of hypertonic saline and myoinositol increased brain myoinositol levels by about 50% above control levels. Brain myoinositol content in animals with uncorrected hyponatremia was about 50% of that found in normonatremic controls; concurrent infusion of hypertonic saline and myoinositol increased brain myoinositol to levels similar to those found in normonatremic controls. Intravenous infusion of myoinositol did not alter brain water content compared with animals not infused with myoinositol. In conclusion, systemic infusion of myoinositol can rapidly increase brain myoinositol content, but only when plasma tonicity is concomitantly increased.
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Affiliation(s)
- Stephen M Silver
- Department of Medicine, Rochester General Hospital, University of Rochester School of Medicine, Rochester, New York
| | - Barbara M Schroeder
- Department of Medicine, Rochester General Hospital, University of Rochester School of Medicine, Rochester, New York
| | - Richard H Sterns
- Department of Medicine, Rochester General Hospital, University of Rochester School of Medicine, Rochester, New York
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32
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Oztaş B, Koçak H, Oner P, Küçük M. Sex-dependent changes in blood-brain barrier permeability and brain NA(+),K(+) ATPase activity in rats following acute water intoxication. J Neurosci Res 2000; 62:750-3. [PMID: 11104514 DOI: 10.1002/1097-4547(20001201)62:5<750::aid-jnr15>3.0.co;2-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To understand the increased susceptibility of the development of serious complications to hypoosmotic hyponatremia in young females, we examined the resistance of blood brain barrier (BBB) permeability to water along with the synaptosomal Na(+),K(+)ATPase activity in both sexes of rats during acute water intoxication. Four groups of rats were used: Group I and II were normal female and male rats injected with only Evans-blue. Group III and IV were water intoxicated female and male rats respectively. BBB permeability in female rats was found to be increased following acute water intoxication. In contrast, synaptosomal Na(+),K(+)ATPase activities in both water intoxicated male and female rats were found significantly lower than those in control rats. But inhibition in enzyme activity in synaptosomes from water intoxicated female rats was more pronounced than those of corresponding male rats. Our results concluded that female sex steroids may be responsible for the highly significant decrease in synaptosomal Na(+),K(+)ATPase activity and increased BBB permeability in female rats following water intoxication.
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Affiliation(s)
- B Oztaş
- Department of Physiology, Istanbul Faculty of Medicine, University of Istanbul, Capa, Istanbul, Turkey
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Baker EA, Tian Y, Adler S, Verbalis JG. Blood-brain barrier disruption and complement activation in the brain following rapid correction of chronic hyponatremia. Exp Neurol 2000; 165:221-30. [PMID: 10993682 DOI: 10.1006/exnr.2000.7474] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In previous studies we developed a rat model in which demyelination is reproducibly produced following rapid correction of chronic hyponatremia and demonstrated that the development of demyelination in this model is strongly associated with NMR indices of blood-brain barrier (BBB) disruption. Because complement is toxic to oligodendrocytes, we evaluated the hypothesis that BBB disruption precipitated by correction of hypoosmolality is followed by an influx of complement into the brain, which then contributes to the demyelination that occurs under these conditions. We studied four groups of rats with immunocytochemical analysis using primary antibodies to IgG and the C3d split-fragment of activated complement: (1) normal rats; (2) rats in which hyponatremia was maintained for 7 days; (3) chronically hyponatremic rats in which the plasma [Na(+)] was rapidly corrected with hypertonic saline administration 20 h prior to perfusion; and (4) chronically hyponatremic rats in which the plasma [Na(+)] was rapidly corrected with hypertonic saline administration 5 days prior to perfusion. In normonatremic and uncorrected hyponatremic rats only background staining was observed in areas lacking a BBB and in blood vessel walls, whereas marked increases in IgG and C3d staining were seen in the brains of rats both 20 h and 5 days after rapid correction of hyponatremia. The staining intensity was significantly correlated with the degree of neurological impairment. These results provide evidence for functional BBB disruption following rapid correction of hyponatremia and support the hypothesis that complement activation may be involved in the pathogenesis of osmotic demyelination.
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Affiliation(s)
- E A Baker
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC, USA
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Adler S, Martinez J, Williams DS, Verbalis JG. Positive association between blood brain barrier disruption and osmotically-induced demyelination. Mult Scler 2000; 6:24-31. [PMID: 10694842 DOI: 10.1177/135245850000600106] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Rapid correction of chronic hyponatremia can cause osmotic brain demyelination in animals and humans. Why demyelination develops is unknown, but blood brain-barrier disruption might expose oligodendrocytes to substances normally excluded from the brain. To test this hypothesis, chronic hyponatremia was induced and corrected using a new, reproducible rat model for producing osmotic brain demyelination. Blood brain barrier integrity was assessed by NMR imaging at either 3, 16 or 24 h during the first day of correction. Demyelination was determined histopathologically 5 - 6 days later. Of 96 rats studied, demyelination developed 5 - 6 days later in 37 rats, 89% of whom showed barrier disruption. In the 59 rats who did not develop demyelination, 45 (76%) had no barrier disruption. Thus, blood-brain barrier disruption during the first 24 h of correction was associated with a 70% risk of developing demyelination. By contrast, the risk of developing subsequent demyelination was only 8% when the barrier was intact. This strong association between barrier disruption and subsequent demyelination provides new insights into the role of blood brain barrier function in demyelinative disorders such as the osmotic demyelination syndrome and by extension to other demyelinative disorders such as multiple sclerosis.
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Affiliation(s)
- S Adler
- Department of Medicine, University of Pittsburgh School of Medicine, 937 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15216, USA
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Soupart A, Penninckx R, Stenuit A, Decaux G. Azotemia (48 h) decreases the risk of brain damage in rats after correction of chronic hyponatremia. Brain Res 2000; 852:167-72. [PMID: 10661508 DOI: 10.1016/s0006-8993(99)02259-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Brain myelinolysis complicates excessive correction of chronic hyponatremia in man. Myelinolysis appear in rats for correction levels deltaSNa) > 20 mEq/l/24 h. We previously showed in rats that when chronic hyponatremia was corrected with urea, the incidence and the severity of brain lesions were significantly reduced compared to hypertonic saline. In man, hyponatremia is frequently associated with azotemia and hemo-dialysis usually corrects rapidly the serum sodium (SNa) but only few patients apparently develop demyelination. We hypothesize that uremic state protects brain against myelinolysis. This hypothesis was evaluated in rats developing azotemia by administration of mercuric chloride (HgCl2, 1.5 mg/kg). Severe (SNa < 120 mEq/l) hyponatremia (3 days) was induced by S.C. AVP and i.p. 2.5% D-glucose for 3 days. HgCl2 was injected on day 2. Hyponatremia was corrected on day 4 by i.p. injections of 5% NaCl in order to obtain a correction level largely above the toxic threshold for brain (deltaSNA approximately 30 mEq/l/24 h). Surviving rats were decapitated on day 10 for brain analysis. In the group with renal failure (Group I, n = 15, urea 59 mmol/l) the outcome was remarkably favourable with only three rats (3/15) dying before day 10 and only one of them (1/3) presenting myelinolysis-related neurologic symptoms. The 12 other rats (80%) survived in Group I without symptoms and brain analysis was normal in all of them despite large correction level (deltaSNa: 32 mEq/l/24 h). On the contrary in nine rats in which HgCl, did not produce significant azotemia (control 1, n = 9, urea: 11 mmol/l), all the rats developed severe neurologic symptoms and eight of them died before day 10. Similar catastrophic outcome was observed in the non-azotemic controls (control 2, no HgCl2 administration, n = 15, urea: 5 mmol/l). All of them developed myelinolysis-related neurologic symptoms and only four of them survived with severe brain lesions (survival 12/15 in Group I vs. 5/24 in pooled controls 1 and 2, p < 0.001). In conclusion, we showed for the first time that chronic hyponatremic rats with azotemia (48 h) tolerated large increases in SNa (approximately 30 mEq/l/24 h) without significant brain damage.
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Affiliation(s)
- A Soupart
- Research Unit for the Study of Hydromineral Metabolism, Erasmus University Hospital, Free University of Brussels, Belgium
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