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González-Duarte A, Cotrina-Vidal M, Kaufmann H, Norcliffe-Kaufmann L. Familial dysautonomia. Clin Auton Res 2023; 33:269-280. [PMID: 37204536 DOI: 10.1007/s10286-023-00941-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/30/2023] [Indexed: 05/20/2023]
Abstract
Familial dysautonomia (FD) is an autosomal recessive hereditary sensory and autonomic neuropathy (HSAN, type 3) expressed at birth with profound sensory loss and early death. The FD founder mutation in the ELP1 gene arose within the Ashkenazi Jews in the sixteenth century and is present in 1:30 Jews of European ancestry. The mutation yield a tissue-specific skipping of exon 20 and a loss of function of the elongator-1 protein (ELP1), which is essential for the development and survival of neurons. Patients with FD produce variable amounts of ELP1 in different tissues, with the brain producing mostly mutant transcripts. Patients have excessive blood pressure variability due to the failure of the IXth and Xth cranial nerves to carry baroreceptor signals. Neurogenic dysphagia causes frequent aspiration leading to chronic pulmonary disease. Characteristic hyperadrenergic "autonomic crises" consisting of brisk episodes of severe hypertension, tachycardia, skin blotching, retching, and vomiting occur in all patients. Progressive features of the disease include retinal nerve fiber loss and blindness, and proprioceptive ataxia with severe gait impairment. Chemoreflex failure may explain the high frequency of sudden death in sleep. Although 99.5% of patients are homozygous for the founder mutation, phenotypic severity varies, suggesting that modifier genes impact expression. Medical management is currently symptomatic and preventive. Disease-modifying therapies are close to clinical testing. Endpoints to measure efficacy have been developed, and the ELP1 levels are a good surrogate endpoint for target engagement. Early intervention may be critical for treatment to be successful.
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Affiliation(s)
- Alejandra González-Duarte
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA.
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, CdMx, México.
| | - Maria Cotrina-Vidal
- Department of Neurology, Stroke Division. New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
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Ramprasad C, Palma JA, Norcliffe-Kaufmann L, Levy J, Chen LA, Kaufmann H. Gastrointestinal bleeding in children with familial dysautonomia: a case-control study. Clin Auton Res 2023; 33:87-92. [PMID: 36735101 DOI: 10.1007/s10286-023-00925-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/16/2023] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Familial dysautonomia (FD) is a rare inherited autosomal recessive disorder with abnormal somatosensory, enteric, and afferent autonomic neurons. We aimed to define the incidence of gastrointestinal bleeding and its associated risk factors in patients with FD. METHODS In this retrospective case-control study, we identified all episodes of gastrointestinal bleeding in patients with FD, occurring over four decades (January 1980-December 2017), using the New York University FD registry. RESULTS We identified 104 episodes of gastrointestinal bleeding occurring in 60 patients with FD. The estimated incidence rate of gastrointestinal bleeds in the FD population rate was 4.20 episodes per 1000 person-years. We compared the 60 cases with 94 age-matched controls. Bleeding in the upper gastrointestinal tract from gastric and duodenal ulcers occurred most frequently (64 bleeds, 75.6%). Patients were more likely to have a gastrostomy (G)-tube and a Nissen fundoplication [odds ratio (OR) 3.73, 95% confidence interval (CI) 1.303-13.565] than controls. The mean time from G-tube placement to first gastrointestinal bleed was 7.01 years. The mean time from Nissen fundoplication to bleed was 7.01 years. Cases and controls had similar frequency of intake of nonsteroidal antiinflammatory drugs (NSAID) and selective serotonin reuptake inhibitors (SSRI). CONCLUSION The incidence of gastrointestinal bleeding in the pediatric FD population was estimated to be 4.20 per 1000 person-years, 21 times higher than in the general pediatric population (0.2 per 1000 person-years). Patients with FD with a G-tube and a Nissen fundoplication had a higher risk of a subsequent gastrointestinal bleeding.
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Affiliation(s)
- Chethan Ramprasad
- Division of Gastroenterology and Hepatology, Department of Medicine, New York University Grossman School of Medicine, New York City, NY, USA
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University Grossman School of Medicine, 530 First Av, Suite 9Q, New York City, NY, 10016, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University Grossman School of Medicine, 530 First Av, Suite 9Q, New York City, NY, 10016, USA
| | - Joseph Levy
- Division of Pediatric Gastroenterology, New York University Grossman School of Medicine, New York City, NY, USA
| | - Lea Ann Chen
- Division of Gastroenterology and Hepatology, Department of Medicine, New York University Grossman School of Medicine, New York City, NY, USA
- Division of Gastroenterology and Hepatology, Rutgers University, Robert Wood Johnson School of Medicine, New Brunswick, NJ, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University Grossman School of Medicine, 530 First Av, Suite 9Q, New York City, NY, 10016, USA.
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Younger DS. Autonomic failure: Clinicopathologic, physiologic, and genetic aspects. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:55-102. [PMID: 37562886 DOI: 10.1016/b978-0-323-98818-6.00020-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Over the past century, generations of neuroscientists, pathologists, and clinicians have elucidated the underlying causes of autonomic failure found in neurodegenerative, inherited, and antibody-mediated autoimmune disorders, each with pathognomonic clinicopathologic features. Autonomic failure affects central autonomic nervous system components in the α-synucleinopathy, multiple system atrophy, characterized clinically by levodopa-unresponsive parkinsonism or cerebellar ataxia, and pathologically by argyrophilic glial cytoplasmic inclusions (GCIs). Two other central neurodegenerative disorders, pure autonomic failure characterized clinically by deficits in norepinephrine synthesis and release from peripheral sympathetic nerve terminals; and Parkinson's disease, with early and widespread autonomic deficits independent of the loss of striatal dopamine terminals, both express Lewy pathology. The rare congenital disorder, hereditary sensory, and autonomic neuropathy type III (or Riley-Day, familial dysautonomia) causes life-threatening autonomic failure due to a genetic mutation that results in loss of functioning baroreceptors, effectively separating afferent mechanosensing neurons from the brain. Autoimmune autonomic ganglionopathy caused by autoantibodies targeting ganglionic α3-acetylcholine receptors instead presents with subacute isolated autonomic failure affecting sympathetic, parasympathetic, and enteric nervous system function in various combinations. This chapter is an overview of these major autonomic disorders with an emphasis on their historical background, neuropathological features, etiopathogenesis, diagnosis, and treatment.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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Rescue of a familial dysautonomia mouse model by AAV9-Exon-specific U1 snRNA. Am J Hum Genet 2022; 109:1534-1548. [PMID: 35905737 PMCID: PMC9388384 DOI: 10.1016/j.ajhg.2022.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/30/2022] [Indexed: 02/06/2023] Open
Abstract
Familial dysautonomia (FD) is a currently untreatable, neurodegenerative disease caused by a splicing mutation (c.2204+6T>C) that causes skipping of exon 20 of the elongator complex protein 1 (ELP1) pre-mRNA. Here, we used adeno-associated virus serotype 9 (AAV9-U1-FD) to deliver an exon-specific U1 (ExSpeU1) small nuclear RNA, designed to cause inclusion of ELP1 exon 20 only in those cells expressing the target pre-mRNA, in a phenotypic mouse model of FD. Postnatal systemic and intracerebral ventricular treatment in these mice increased the inclusion of ELP1 exon 20. This also augmented the production of functional protein in several tissues including brain, dorsal root, and trigeminal ganglia. Crucially, the treatment rescued most of the FD mouse mortality before one month of age (89% vs 52%). There were notable improvements in ataxic gait as well as renal (serum creatinine) and cardiac (ejection fraction) functions. RNA-seq analyses of dorsal root ganglia from treated mice and human cells overexpressing FD-ExSpeU1 revealed only minimal global changes in gene expression and splicing. Overall then, our data prove that AAV9-U1-FD is highly specific and will likely be a safe and effective therapeutic strategy for this debilitating disease.
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Norcliffe-Kaufmann L. Stress and the baroreflex. Auton Neurosci 2022; 238:102946. [PMID: 35086020 DOI: 10.1016/j.autneu.2022.102946] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 11/27/2022]
Abstract
The stress response to emotions elicits the release of glucocorticoids from the adrenal cortex, epinephrine from the adrenal medulla, and norepinephrine from the sympathetic nerves. The baroreflex adapts to buffer these responses to ensure that perfusion to the organs meets the demands while maintaining blood pressure within a within a narrow range. While stressor-evoked autonomic cardiovascular responses may be adaptive for the short-term, the recurrent exaggerated cardiovascular stress reactions can be maladaptive in the long-term. Prolonged stress or loss of the baroreflex's buffering capacity can predispose episodes of heightened sympathetic activity during stress leading to hypertension, tachycardia, and ventricular wall motion abnormalities. This review discusses 1) how the baroreflex responds to acute and chronic stressors, 2) how lesions in the neuronal pathways of the baroreflex alter the ability to respond or counteract the stress response, and 3) the techniques to assess baroreflex sensitivity and stress responses. Evidence suggests that loss of baroreflex sensitivity may predispose heightened autonomic responses to stress and at least in part explain the association between stress, mortality and cardiovascular diseases.
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Tanzer TD, Brouard T, Pra SD, Warren N, Barras M, Kisely S, Brooks E, Siskind D. Treatment strategies for clozapine-induced hypotension: a systematic review. Ther Adv Psychopharmacol 2022; 12:20451253221092931. [PMID: 35633931 PMCID: PMC9136453 DOI: 10.1177/20451253221092931] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/22/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Clozapine is the most effective medication for treatment-refractory schizophrenia but is associated with significant adverse drug effects, including hypotension and dizziness, which have a negative impact on quality of life and treatment compliance. Available evidence for the management of clozapine-induced hypotension is scant. OBJECTIVES Due to limited guidance on the safety and efficacy of pharmacological treatments for clozapine-induced hypotension, we set out to systematically review and assess the evidence for the management of clozapine-induced hypotension and provide guidance to clinicians, patients, and carers. DESIGN We undertook a systematic review of the safety and efficacy of interventions for clozapine-induced hypotension given the limited available evidence. DATA SOURCES AND METHODS PubMed, Embase, PsycINFO, CINAHL, and the Cochrane trial Registry were searched from inception to November 2021 for literature on the treatment strategies for clozapine-induced hypotension and dizziness using a PROSPERO pre-registered search strategy. For orthostatic hypotension, we developed a management framework to assist in the choice of intervention. RESULTS We identified nine case studies and four case series describing interventions in 15 patients. Hypotension interventions included temporary clozapine dose reduction, non-pharmacological treatments, and pharmacological treatments. Midodrine, fludrocortisone, moclobemide and Bovril® combination, and etilefrine were associated with improvement in symptoms or reduction in orthostatic hypotension. Angiotensin II, arginine vasopressin, and noradrenaline successfully restored and maintained mean arterial pressure in critical care situations. A paradoxical reaction of severe hypotension was reported with adrenaline use. CONCLUSION Orthostatic hypotension is a common side effect during clozapine titration. Following an assessment of the titration schedule, salt and fluid intake, and review of hypertensive and nonselective α1-adrenergic agents, first-line treatment should be a temporary reduction in clozapine dose or non-pharmacological interventions. If orthostatic hypotension persists, fludrocortisone should be trialled with monitoring of potassium levels and sodium and fluid intake. Midodrine may be considered second-line or where fludrocortisone is contraindicated or poorly tolerated. For patients on clozapine with hypotension in critical care settings, the use of adrenaline to maintain mean arterial pressure should be avoided. REGISTRATION PROSPERO (Registration No. CRD42020191530).
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Affiliation(s)
| | - Thomas Brouard
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Samuel Dal Pra
- Metro South Addiction and Mental Health Services, Brisbane, QLD, Australia
| | - Nicola Warren
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Michael Barras
- Department of Pharmacy, Princess Alexandra Hospital, Brisbane, QLD, Australia School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
| | - Steve Kisely
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Emily Brooks
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Dan Siskind
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
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Vahidi G, Flook H, Sherk V, Mergy M, Lefcort F, Heveran CM. Bone biomechanical properties and tissue-scale bone quality in a genetic mouse model of familial dysautonomia. Osteoporos Int 2021; 32:2335-2346. [PMID: 34036438 PMCID: PMC8563419 DOI: 10.1007/s00198-021-06006-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Familial dysautonomia (FD) is associated with a high prevalence of bone fractures, but the impacts of the disease on bone mass and quality are unclear. The purpose of this study was to evaluate tissue through whole-bone scale bone quality in a mouse model of FD. METHODS Femurs from mature adult Tuba1a-Cre; Elp1LoxP/LoxP conditional knockouts (CKO) (F = 7, M = 4) and controls (F = 5, M = 6) were evaluated for whole-bone flexural material properties, trabecular microarchitecture and cortical geometry, and areal bone mineral density (BMD). Adjacent maps spanning the thickness of femur midshaft cortical bone assessed tissue-scale modulus (nanoindentation), bone mineralization, mineral maturity, and collagen secondary structure (Raman spectroscopy). RESULTS Consistent with prior studies on this mouse model, the Elp1 CKO mouse model recapitulated several key hallmarks of human FD, with one difference being the male mice tended to have a more severe phenotype than females. Deletion of Elp1 in neurons (using the neuronal-specific Tuba1a-cre) led to a significantly reduced whole-bone toughness but not strength or modulus. Elp1 CKO female mice had reduced trabecular microarchitecture (BV/TV, Tb.Th, Conn.D.) but not cortical geometry. The mutant mice also had a small but significant reduction in cortical bone nanoindentation modulus. While bone tissue mineralization and mineral maturity were not impaired, FD mice may have altered collagen secondary structure. Changes in collagen secondary structure were inversely correlated with bone toughness. BMD from dual-energy x-ray absorptiometry (DXA) was unchanged with FD. CONCLUSION The deletion of Elp1 in neurons is sufficient to generate a mouse line which demonstrates loss of whole-bone toughness, consistent with the poor bone quality suspected in the clinical setting. The Elp1 CKO model, as with human FD, impacts the nervous system, gut, kidney function, mobility, gait, and posture. The bone quality phenotype of Elp1 CKO mice, which includes altered microarchitecture and tissue-scale material properties, is complex and likely influenced by these multisystemic changes. This mouse model may provide a useful platform to not only investigate the mechanisms responsible for bone fragility in FD, but also a powerful model system with which to evaluate potential therapeutic interventions for bone fragility in FD patients.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - H Flook
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - V Sherk
- Department of Orthopaedics, University of Colorado School of Medicine, Aurora, CO, USA
| | - M Mergy
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - F Lefcort
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - C M Heveran
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA.
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Harada Y, Guptill JT. Management/Treatment of Lambert-Eaton Myasthenic Syndrome. Curr Treat Options Neurol 2021. [DOI: 10.1007/s11940-021-00690-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
PURPOSE OF REVIEW This article reviews the management of orthostatic hypotension with emphasis on neurogenic orthostatic hypotension. RECENT FINDINGS Establishing whether the cause of orthostatic hypotension is a pathologic lesion in sympathetic neurons (ie, neurogenic orthostatic hypotension) or secondary to other medical causes (ie, non-neurogenic orthostatic hypotension) can be achieved by measuring blood pressure and heart rate at the bedside. Whereas fludrocortisone has been extensively used as first-line treatment in the past, it is associated with adverse events including renal and cardiac failure and increased risk of all-cause hospitalization. Distinguishing whether neurogenic orthostatic hypotension is caused by central or peripheral dysfunction has therapeutic implications. Patients with peripheral sympathetic denervation respond better to norepinephrine agonists/precursors such as droxidopa, whereas patients with central autonomic dysfunction respond better to norepinephrine reuptake inhibitors. SUMMARY Management of orthostatic hypotension is aimed at improving quality of life and reducing symptoms rather than at normalizing blood pressure. Nonpharmacologic measures are the key to success. Pharmacologic options include volume expansion with fludrocortisone and sympathetic enhancement with midodrine, droxidopa, and norepinephrine reuptake inhibitors. Neurogenic supine hypertension complicates management of orthostatic hypotension and is primarily ameliorated by avoiding the supine position and sleeping with the head of the bed elevated.
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Norcliffe-Kaufmann L, Millar Vernetti P, Palma JA, Balgobin BJ, Kaufmann H. Afferent Baroreflex Dysfunction: Decreased or Excessive Signaling Results in Distinct Phenotypes. Semin Neurol 2020; 40:540-549. [PMID: 32906172 DOI: 10.1055/s-0040-1713892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Head and neck tumors can affect afferent baroreceptor neurons and either interrupt or intermittently increase their signaling, causing blood pressure to become erratic. When the afferent fibers of the baroreflex are injured by surgery or radiotherapy or fail to develop as in familial dysautonomia, their sensory information is no longer present to regulate arterial blood pressure, resulting in afferent baroreflex failure. When the baroreflex afferents are abnormally activated, such as by paragangliomas in the neck, presumably by direct compression, they trigger acute hypotension and bradycardia and frequently syncope, by a mechanism similar to the carotid sinus syndrome. We describe our observations in a large series of 23 patients with afferent baroreflex dysfunction and the cardiovascular autonomic features that arise when the sensory baroreceptor neurons are injured or compressed. The management of afferent baroreceptor dysfunction is limited, but pharmacological strategies can mitigate blood pressure swings, improve symptoms, and may reduce hypertensive organ damage. Although rare, the prevalence of afferent baroreflex dysfunction appears to be increasing in middle-aged men due to human papillomavirus related oropharyngeal cancer.
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Affiliation(s)
| | | | - Jose-Alberto Palma
- Department of Neurology, New York University School of Medicine, New York, New York
| | - Bhumika J Balgobin
- Department of Neurology, New York University School of Medicine, New York, New York
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, New York
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Norcliffe-Kaufmann L, Palma JA, Martinez J, Kaufmann H. Carbidopa for Afferent Baroreflex Failure in Familial Dysautonomia: A Double-Blind Randomized Crossover Clinical Trial. Hypertension 2020; 76:724-731. [PMID: 32654554 DOI: 10.1161/hypertensionaha.120.15267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Afferent lesions of the arterial baroreflex occur in familial dysautonomia. This leads to excessive blood pressure variability with falls and frequent surges that damage the organs. These hypertensive surges are the result of excess peripheral catecholamine release and have no adequate treatment. Carbidopa is a selective DOPA-decarboxylase inhibitor that suppresses catecholamines production outside the brain. To learn whether carbidopa can inhibit catecholamine-induced hypertensive surges in patients with severe afferent baroreflex failure, we conducted a double-blind randomized crossover trial in which patients with familial dysautonomia received high dose carbidopa (600 mg/day), low-dose carbidopa (300 mg/day), or matching placebo in 3 4-week treatment periods. Among the 22 patients enrolled (13 females/8 males), the median age was 26 (range, 12-59 years). At enrollment, patients had hypertensive peaks to 164/116 (range, 144/92 to 213/150 mm Hg). Twenty-four hour urinary norepinephrine excretion, a marker of peripheral catecholamine release, was significantly suppressed on both high dose and low dose carbidopa, compared with placebo (P=0.0075). The 2 co-primary end points of the trial were met. The SD of systolic BP variability was reduced at both carbidopa doses (low dose: 17±4; high dose: 18±5 mm Hg) compared with placebo (23±7 mm Hg; P=0.0013), and there was a significant reduction in the systolic BP peaks on active treatment (P=0.0015). High- and low-dose carbidopa were similarly effective and well tolerated. This study provides class Ib evidence that carbidopa can reduce blood pressure variability in patients with congenital afferent baroreflex failure. Similar beneficial effects are observed in patients with acquired baroreflex lesions.
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Affiliation(s)
- Lucy Norcliffe-Kaufmann
- From the Department of Neurology, NYU Dysautonomia Center, New York University School of Medicine
| | - Jose-Alberto Palma
- From the Department of Neurology, NYU Dysautonomia Center, New York University School of Medicine
| | - Jose Martinez
- From the Department of Neurology, NYU Dysautonomia Center, New York University School of Medicine
| | - Horacio Kaufmann
- From the Department of Neurology, NYU Dysautonomia Center, New York University School of Medicine
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Affiliation(s)
- Horacio Kaufmann
- From the Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York
| | - Lucy Norcliffe-Kaufmann
- From the Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York
| | - Jose-Alberto Palma
- From the Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York
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Abstract
Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing that can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions. OH can be caused by volume depletion, blood loss, cardiac pump failure, large varicose veins, medications, or defective activation of sympathetic nerves and reduced norepinephrine release upon standing. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and it is commonly associated with supine hypertension. Several therapeutic options are available.
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Orthostatic hypotension in hereditary transthyretin amyloidosis: epidemiology, diagnosis and management. Clin Auton Res 2019; 29:33-44. [PMID: 31452021 PMCID: PMC6763509 DOI: 10.1007/s10286-019-00623-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/30/2019] [Indexed: 02/06/2023]
Abstract
Purpose Neurogenic orthostatic hypotension is a prominent and disabling manifestation of autonomic dysfunction in patients with hereditary transthyretin (TTR) amyloidosis affecting an estimated 40–60% of patients, and reducing their quality of life. We reviewed the epidemiology and pathophysiology of neurogenic orthostatic hypotension in patients with hereditary TTR amyloidosis, summarize non-pharmacologic and pharmacological treatment strategies and discuss the impact of novel disease-modifying treatments such as transthyretin stabilizers (diflunisal, tafamidis) and RNA interference agents (patisiran, inotersen). Methods Literature review. Results Orthostatic hypotension in patients with hereditary transthyretin amyloidosis can be a consequence of heart failure due to amyloid cardiomyopathy or volume depletion due to diarrhea or drug effects. When none of these circumstances are apparent, orthostatic hypotension is usually neurogenic, i.e., caused by impaired norepinephrine release from sympathetic postganglionic neurons, because of neuronal amyloid fibril deposition. Conclusions When recognized, neurogenic orthostatic hypotension can be treated. Discontinuation of potentially aggravating medications, patient education and non-pharmacologic approaches should be applied first. Droxidopa (Northera®), a synthetic norepinephrine precursor, has shown efficacy in controlled trials of neurogenic orthostatic hypotension in patients with hereditary TTR amyloidosis and is now approved in the US and Asia. Although they may be useful to ameliorate autonomic dysfunction in hereditary TTR amyloidosis, the impact of disease-modifying treatments on neurogenic orthostatic hypotension is still uninvestigated.
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Abstract
PURPOSE OF REVIEW Hereditary sensory and autonomic neuropathies (HSANs) are a clinically heterogeneous group of inherited neuropathies featuring prominent sensory and autonomic involvement. Classification of HSAN is based on mode of inheritance, genetic mutation, and phenotype. In this review, we discuss the recent additions to this classification and the important updates on management with a special focus on the recently investigated disease-modifying agents. RECENT FINDINGS In this past decade, three more HSAN types were added to the classification creating even more diversity in the genotype-phenotype. Clinical trials are underway for disease-modifying and symptomatic therapeutics, targeting mainly HSAN type III. Obtaining genetic testing leads to accurate diagnosis and guides focused management in the setting of such a diverse and continuously growing phenotype. It also increases the wealth of knowledge on HSAN pathophysiologies which paves the way toward development of targeted genetic treatments in the era of precision medicine.
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Palma JA, Gileles-Hillel A, Norcliffe-Kaufmann L, Kaufmann H. Chemoreflex failure and sleep-disordered breathing in familial dysautonomia: Implications for sudden death during sleep. Auton Neurosci 2019; 218:10-15. [PMID: 30890343 DOI: 10.1016/j.autneu.2019.02.003] [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: 01/08/2019] [Accepted: 02/11/2019] [Indexed: 01/04/2023]
Abstract
Familial dysautonomia (Riley-Day syndrome, hereditary sensory and autonomic neuropathy type III) is a rare autosomal recessive disease characterized by impaired development of primary sensory and autonomic neurons resulting in a severe neurological phenotype, which includes arterial baroreflex and chemoreflex failure with high frequency of sleep-disordered breathing and sudden death during sleep. Although a rare disease, familial dysautonomia represents a unique template to study the interactions between sleep-disordered breathing and abnormal chemo- and baroreflex function. In patients with familial dysautonomia, ventilatory responses to hypercapnia are reduced, and to hypoxia are almost absent. In response to hypoxia, these patients develop paradoxical hypoventilation, hypotension, bradycardia, and potentially, death. Impaired ventilatory control due to chemoreflex failure acquires special relevance during sleep when conscious control of respiration withdraws. Overall, almost all adult (85%) and pediatric (95%) patients have some degree of sleep-disordered breathing. Obstructive apnea events are more frequent in adults, whereas central apnea events are more severe and frequent in children. The annual incidence rate of sudden death during sleep in patients with familial dysautonomia is 3.4 per 1000 person-year, compared to 0.5-1 per 1000 person-year of sudden unexpected death in epilepsy. This review summarizes recent developments in the understanding of sleep-disordered breathing in patients with familial dysautonomia, the risk factors for sudden death during sleep, and the specific interventions that could prevent it.
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Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America
| | - Alex Gileles-Hillel
- Departments of Pediatrics, Pediatric Pulmonology and Sleep, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States of America.
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Cutsforth-Gregory JK, Sandroni P. Clinical neurophysiology of postural tachycardia syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2019; 161:429-445. [PMID: 31307619 DOI: 10.1016/b978-0-444-64142-7.00066-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Postural tachycardia syndrome (POTS) is one of several disorders of orthostatic intolerance (OI). It is defined by the development of symptoms of cerebral hypoperfusion or sympathetic activation and a sustained heart rate increment of 30 beats/min or more (40 beats/min for teenagers) within 10min of standing or head-up tilt in the absence of orthostatic hypotension; the standing heart rate is often 120 beats/min or higher. POTS is approximately five times more common in women than men. This heterogeneous syndrome is caused by several pathophysiologic mechanisms (limited autonomic neuropathy, hyperadrenergic state, hypovolemia, venous pooling, deconditioning), which are not mutually exclusive. Anxiety and somatic hypervigilance play significant roles in POTS. Common comorbidities include visceral pain and dysmotility, chronic fatigue and fibromyalgia, migraine, joint hypermobility, mitral valve prolapse, and inappropriate sinus tachycardia. Patients with suspected POTS should undergo comprehensive cardiac and neurologic examinations and autonomic and laboratory tests to determine the most likely pathophysiologic basis of OI. The objectives of POTS management are to (1) increase the time that patients can stand, perform daily activities, and exercise and (2) avoid syncope. Management involves nonpharmacologic (fluid and salt loading, physical countermaneuvers, compression garments, exercise training) and pharmacologic (β-blockers, pyridostigmine, fludrocortisone, midodrine) approaches.
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Affiliation(s)
| | - Paola Sandroni
- Department of Neurology, Mayo Clinic, Rochester, MN, United States.
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19
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Palma JA, Kaufmann H. Treatment of autonomic dysfunction in Parkinson disease and other synucleinopathies. Mov Disord 2018; 33:372-390. [PMID: 29508455 PMCID: PMC5844369 DOI: 10.1002/mds.27344] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/11/2018] [Accepted: 01/24/2018] [Indexed: 12/12/2022] Open
Abstract
Dysfunction of the autonomic nervous system afflicts most patients with Parkinson disease and other synucleinopathies such as dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure, reducing quality of life and increasing mortality. For example, gastrointestinal dysfunction can lead to impaired drug pharmacodynamics causing a worsening in motor symptoms, and neurogenic orthostatic hypotension can cause syncope, falls, and fractures. When recognized, autonomic problems can be treated, sometimes successfully. Discontinuation of potentially causative/aggravating drugs, patient education, and nonpharmacological approaches are useful and should be tried first. Pathophysiology-based pharmacological treatments that have shown efficacy in controlled trials of patients with synucleinopathies have been approved in many countries and are key to an effective management. Here, we review the treatment of autonomic dysfunction in patients with Parkinson disease and other synucleinopathies, summarize the nonpharmacological and current pharmacological therapeutic strategies including recently approved drugs, and provide practical advice and management algorithms for clinicians, with focus on neurogenic orthostatic hypotension, supine hypertension, dysphagia, sialorrhea, gastroparesis, constipation, neurogenic overactive bladder, underactive bladder, and sexual dysfunction. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York, USA
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Goldberg L, Bar-Aluma BE, Krauthammer A, Efrati O, Sharabi Y. Ambulatory blood pressure profiles in familial dysautonomia. Clin Auton Res 2018; 28:385-390. [PMID: 29435868 DOI: 10.1007/s10286-018-0507-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Familial dysautonomia (FD) is a rare genetic disease that involves extreme blood pressure fluctuations secondary to afferent baroreflex failure. The diurnal blood pressure profile, including the average, variability, and day-night difference, may have implications for long-term end organ damage. The purpose of this study was to describe the circadian pattern of blood pressure in the FD population and relationships with renal and pulmonary function, use of medications, and overall disability. METHODS We analyzed 24-h ambulatory blood pressure monitoring recordings in 22 patients with FD. Information about medications, disease severity, renal function (estimated glomerular filtration, eGFR), pulmonary function (forced expiratory volume in 1 s, FEV1) and an index of blood pressure variability (standard deviation of systolic pressure) were analyzed. RESULTS The mean (± SEM) 24-h blood pressure was 115 ± 5.6/72 ± 2.0 mmHg. The diurnal blood pressure variability was high (daytime systolic pressure standard deviation 22.4 ± 1.5 mmHg, nighttime 17.2 ± 1.6), with a high frequency of a non-dipping pattern (16 patients, 73%). eGFR, use of medications, FEV1, and disability scores were unrelated to the degree of blood pressure variability or to dipping status. INTERPRETATION This FD cohort had normal average 24-h blood pressure, fluctuating blood pressure, and a high frequency of non-dippers. Although there was evidence of renal dysfunction based on eGFR and proteinuria, the ABPM profile was unrelated to the measures of end organ dysfunction or to reported disability.
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Affiliation(s)
- Lior Goldberg
- Pediatric Pulmonary Unit and The National Center for Familial Dysautonomia, Edmond and Lily Safra Children's Pediatric Hospital, Chaim Sheba Medical Center, Tel-HaShomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Bat-El Bar-Aluma
- Pediatric Pulmonary Unit and The National Center for Familial Dysautonomia, Edmond and Lily Safra Children's Pediatric Hospital, Chaim Sheba Medical Center, Tel-HaShomer, Israel. .,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Alex Krauthammer
- Pediatric Pulmonary Unit and The National Center for Familial Dysautonomia, Edmond and Lily Safra Children's Pediatric Hospital, Chaim Sheba Medical Center, Tel-HaShomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ori Efrati
- Pediatric Pulmonary Unit and The National Center for Familial Dysautonomia, Edmond and Lily Safra Children's Pediatric Hospital, Chaim Sheba Medical Center, Tel-HaShomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yehonatan Sharabi
- Hypertension Unit, Chaim Sheba Medical Center, Tel-HaShomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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A Controlled Trial of Inhaled Bronchodilators in Familial Dysautonomia. Lung 2017; 196:93-101. [PMID: 29234869 DOI: 10.1007/s00408-017-0073-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 10/06/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Chronic lung disease is a leading cause of premature death in patients with familial dysautonomia (FD). A significant number of patients have obstructive airway disease, yet it is not known whether this is pharmacologically reversible. METHODS We conducted a double-blind, placebo-controlled, randomized clinical trial comparing the beta 2 agonist albuterol with the muscarinic blocker ipratropium bromide in patients homozygous for the IKBKAP founder mutation. Albuterol, ipratropium bromide, and placebo were administered on 3 separate days via nebulizer in the seated position. Airway responsiveness was evaluated using spirometry and impulse oscillometry 30 min post dose. Cardiovascular effects were evaluated by continuous monitoring of blood pressure, RR intervals, cardiac output, and systemic vascular resistance. RESULTS A total of 14 patients completed the trial. Neither active agent had significant detrimental effects on heart rate or rhythm or blood pressure. Albuterol and ipratropium were similar in their bronchodilator effectiveness causing significant improvement in forced expiratory volume in 1-s (FEV1, p = 0.002 and p = 0.030). Impulse oscillometry measures were consistent with a reduction in total airway resistance post nebulization (resistance at 5 Hz p < 0.006). CONCLUSION Airway obstruction is pharmacologically reversible in a number of patients with FD. In the short term, both albuterol and ipratropium were well tolerated and not associated with major cardiovascular adverse events.
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Palma JA, Norcliffe-Kaufmann L, Perez MA, Spalink CL, Kaufmann H. Sudden Unexpected Death During Sleep in Familial Dysautonomia: A Case-Control Study. Sleep 2017; 40:3831157. [PMID: 28521050 DOI: 10.1093/sleep/zsx083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Study Objectives Sudden unexpected death during sleep (SUDS) is the most common cause of death in patients with familial dysautonomia (FD), an autosomal recessive disease characterized by sensory and autonomic dysfunction. It remains unknown what causes SUDS in these patients and who is at highest risk. We tested the hypothesis that SUDS in FD is linked to sleep-disordered breathing. Methods We retrospectively identified patients with FD who died suddenly and unexpectedly during sleep and had undergone polysomnography within the 18-month period before death. For each case, we sampled one age-matched surviving subject with FD that had also undergone polysomnography within the 18-month period before study. Data on polysomnography, EKG, ambulatory blood pressure monitoring, arterial blood gases, blood count, and metabolic panel were analyzed. Results Thirty-two deceased cases and 31 surviving controls were included. Autopsy was available in six cases. Compared with controls, participants with SUDS were more likely to be receiving treatment with fludrocortisone (odds ratio [OR]; 95% confidence interval) (OR 29.7; 4.1-213.4), have untreated obstructive sleep apnea (OR 17.4; 1.5-193), and plasma potassium levels <4 mEq/L (OR 19.5; 2.36-161) but less likely to use noninvasive ventilation at night (OR 0.19; 0.06-0.61). Conclusions Initiation of noninvasive ventilation when required and discontinuation of fludrocortisone treatment may reduce the high incidence rate of SUDS in patients with FD. Our findings contribute to the understanding of the link between autonomic, cardiovascular, and respiratory risk factors in SUDS.
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Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY
| | - Miguel A Perez
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY
| | - Christy L Spalink
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY
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Eschlböck S, Wenning G, Fanciulli A. Evidence-based treatment of neurogenic orthostatic hypotension and related symptoms. J Neural Transm (Vienna) 2017; 124:1567-1605. [PMID: 29058089 PMCID: PMC5686257 DOI: 10.1007/s00702-017-1791-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/18/2017] [Indexed: 02/06/2023]
Abstract
Neurogenic orthostatic hypotension, postprandial hypotension and exercise-induced hypotension are common features of cardiovascular autonomic failure. Despite the serious impact on patient’s quality of life, evidence-based guidelines for non-pharmacological and pharmacological management are lacking at present. Here, we provide a systematic review of the literature on therapeutic options for neurogenic orthostatic hypotension and related symptoms with evidence-based recommendations according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Patient’s education and non-pharmacological measures remain essential, with strong recommendation for use of abdominal binders. Based on quality of evidence and safety issues, midodrine and droxidopa reach a strong recommendation level for pharmacological treatment of neurogenic orthostatic hypotension. In selected cases, a range of alternative agents can be considered (fludrocortisone, pyridostigmine, yohimbine, atomoxetine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, octreotide, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin), though recommendation strength is weak and quality of evidence is low (atomoxetine, octreotide) or very low (fludrocortisone, pyridostigmine, yohimbine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin). In case of severe postprandial hypotension, acarbose and octreotide are recommended (strong recommendation, moderate level of evidence). Alternatively, voglibose or caffeine, for which a weak recommendation is available, may be useful.
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Affiliation(s)
- Sabine Eschlböck
- Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Gregor Wenning
- Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Alessandra Fanciulli
- Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
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Fuente Mora C, Palma JA, Kaufmann H, Norcliffe-Kaufmann L. Cerebral autoregulation and symptoms of orthostatic hypotension in familial dysautonomia. J Cereb Blood Flow Metab 2017; 37:2414-2422. [PMID: 27613312 PMCID: PMC5531340 DOI: 10.1177/0271678x16667524] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Familial dysautonomia is an inherited autonomic disorder with afferent baroreflex failure. We questioned why despite low blood pressure standing, surprisingly few familial dysautonomia patients complain of symptomatic hypotension or have syncope. Using transcranial Doppler ultrasonography of the middle cerebral artery, we measured flow velocity (mean, peak systolic, and diastolic), area under the curve, pulsatility index, and height of the dictrotic notch in 25 patients with familial dysautonomia and 15 controls. In patients, changing from sitting to a standing position, decreased BP from 124 ± 4/64 ± 3 to 82 ± 3/37 ± 2 mmHg (p < 0.0001, for both). Despite low BP, all patients denied orthostatic symptoms. Middle cerebral artery velocity fell minimally, and the magnitude of the reductions were similar to those observed in healthy controls, in whom BP upright did not fall. While standing, patients had a greater fall in cerebrovascular resistance (p < 0.0001), an increase in pulsatility (p < 0.0001), and a deepening of the dicrotic notch (p = 0.0010), findings all consistent with low cerebrovascular resistance. No significant changes occurred in controls. Patients born with baroreflex deafferentation retain the ability to buffer wide fluctuations in BP and auto-regulate cerebral blood flow. This explains how they can tolerate extremely low BPs standing that would otherwise induce syncope.
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Affiliation(s)
| | | | | | - Lucy Norcliffe-Kaufmann
- Lucy Norcliffe-Kaufmann, Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue, Suite 9Q, New York, NY 10016, USA.
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25
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Palma J, Kaufmann H. Epidemiology, Diagnosis, and Management of Neurogenic Orthostatic Hypotension. Mov Disord Clin Pract 2017; 4:298-308. [PMID: 28713844 PMCID: PMC5506688 DOI: 10.1002/mdc3.12478] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/13/2017] [Accepted: 01/23/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing which can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions particularly in the elderly (233 per 100,000 patients over 75 years of age in the US). OH can be due to volume depletion, blood loss, large varicose veins, medications, or due to defective activation of sympathetic nerves and reduced norepinephrine release upon standing (i.e., neurogenic OH). METHODS AND FINDINGS Literature review. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and is commonly associated with supine hypertension. Several pharmacological and non-pharmacological therapeutic options are available. CONCLUSIONS Here we review the epidemiology, diagnosis, and management of neurogenic OH, and provide an algorithm for its treatment emphasizing the importance of removing aggravating factors, implementing non-pharmacologic measures, and selecting appropriate pharmacological treatments.
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Affiliation(s)
- Jose‐Alberto Palma
- Department of NeurologyDysautonomia CenterNew York University School of MedicineNew YorkNYUSA
| | - Horacio Kaufmann
- Department of NeurologyDysautonomia CenterNew York University School of MedicineNew YorkNYUSA
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26
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Dillon RC, Palma JA, Spalink CL, Altshuler D, Norcliffe-Kaufmann L, Fridman D, Papadopoulos J, Kaufmann H. Dexmedetomidine for refractory adrenergic crisis in familial dysautonomia. Clin Auton Res 2016; 27:7-15. [PMID: 27752785 DOI: 10.1007/s10286-016-0383-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 09/27/2016] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Adrenergic crises are a cardinal feature of familial dysautonomia (FD). Traditionally, adrenergic crises have been treated with the sympatholytic agent clonidine or with benzodiazepines, which can cause excessive sedation and respiratory depression. Dexmedetomidine is a centrally-acting α 2-adrenergic agonist with greater selectivity and shorter half-life than clonidine. We evaluated the preliminary effectiveness and safety of intravenous dexmedetomidine in the treatment of refractory adrenergic crisis in patients with FD. METHODS Retrospective chart review of patients with genetically confirmed FD who received intravenous dexmedetomidine for refractory adrenergic crises. The primary outcome was preliminary effectiveness of dexmedetomidine defined as change in blood pressure (BP) and heart rate (HR) 1 h after the initiation of dexmedetomidine. Secondary outcomes included incidence of adverse events related to dexmedetomidine, hospital and intensive care unit (ICU) length of stay, and hemodynamic parameters 12 h after dexmedetomidine cessation. RESULTS Nine patients over 14 admissions were included in the final analysis. At 1 h after the initiation of dexmedetomidine, systolic BP decreased from 160 ± 7 to 122 ± 7 mmHg (p = 0.0005), diastolic BP decreased from 103 ± 6 to 65 ± 8 (p = 0.0003), and HR decreased from 112 ± 4 to 100 ± 5 bpm (p = 0.0047). The median total adverse events during dexmedetomidine infusion was 1 per admission. Median hospital length of stay was 9 days [interquartile range (IQR) 3-11 days] and median ICU length of stay was 7 days (IQR 3-11 days). CONCLUSIONS Intravenous dexmedetomidine is safe in patients with FD and appears to be effective to treat refractory adrenergic crisis. Dexmedetomidine may be considered in FD patients who do not respond to conventional clonidine and benzodiazepine pharmacotherapy.
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Affiliation(s)
- Ryan C Dillon
- Department of Pharmacy, NYU Langone Medical Center, New York, NY, USA
| | - Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue Suite 9Q, New York, NY, 10016, USA
| | - Christy L Spalink
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue Suite 9Q, New York, NY, 10016, USA
| | - Diana Altshuler
- Department of Pharmacy, NYU Langone Medical Center, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue Suite 9Q, New York, NY, 10016, USA
| | - David Fridman
- Department of Medicine, NYU Langone Medical Center, New York, NY, USA
| | - John Papadopoulos
- Department of Pharmacy, NYU Langone Medical Center, New York, NY, USA
- Department of Medicine, NYU Langone Medical Center, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue Suite 9Q, New York, NY, 10016, USA.
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Dietrich P, Dragatsis I. Familial Dysautonomia: Mechanisms and Models. Genet Mol Biol 2016; 39:497-514. [PMID: 27561110 PMCID: PMC5127153 DOI: 10.1590/1678-4685-gmb-2015-0335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/16/2016] [Indexed: 11/22/2022] Open
Abstract
Hereditary Sensory and Autonomic Neuropathies (HSANs) compose a heterogeneous group of genetic disorders characterized by sensory and autonomic dysfunctions. Familial Dysautonomia (FD), also known as HSAN III, is an autosomal recessive disorder that affects 1/3,600 live births in the Ashkenazi Jewish population. The major features of the disease are already present at birth and are attributed to abnormal development and progressive degeneration of the sensory and autonomic nervous systems. Despite clinical interventions, the disease is inevitably fatal. FD is caused by a point mutation in intron 20 of the IKBKAP gene that results in severe reduction in expression of IKAP, its encoded protein. In vitro and in vivo studies have shown that IKAP is involved in multiple intracellular processes, and suggest that failed target innervation and/or impaired neurotrophic retrograde transport are the primary causes of neuronal cell death in FD. However, FD is far more complex, and appears to affect several other organs and systems in addition to the peripheral nervous system. With the recent generation of mouse models that recapitulate the molecular and pathological features of the disease, it is now possible to further investigate the mechanisms underlying different aspects of the disorder, and to test novel therapeutic strategies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
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Norcliffe-Kaufmann L, Slaugenhaupt SA, Kaufmann H. Familial dysautonomia: History, genotype, phenotype and translational research. Prog Neurobiol 2016; 152:131-148. [PMID: 27317387 DOI: 10.1016/j.pneurobio.2016.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 01/30/2023]
Abstract
Familial dysautonomia (FD) is a rare neurological disorder caused by a splice mutation in the IKBKAP gene. The mutation arose in the 1500s within the small Jewish founder population in Eastern Europe and became prevalent during the period of rapid population expansion within the Pale of Settlement. The carrier rate is 1:32 in Jews descending from this region. The mutation results in a tissue-specific deficiency in IKAP, a protein involved in the development and survival of neurons. Patients homozygous for the mutations are born with multiple lesions affecting mostly sensory (afferent) fibers, which leads to widespread organ dysfunction and increased mortality. Neurodegenerative features of the disease include progressive optic atrophy and worsening gait ataxia. Here we review the progress made in the last decade to better understand the genotype and phenotype. We also discuss the challenges of conducting controlled clinical trials in this rare medically fragile population. Meanwhile, the search for better treatments as well as a neuroprotective agent is ongoing.
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Affiliation(s)
| | - Susan A Slaugenhaupt
- Center for Human Genetic Research, Massachusetts General Hospital Research Institute and Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA.
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Norcliffe-Kaufmann L, Palma JA, Kaufmann H. Mother-induced hypertension in familial dysautonomia. Clin Auton Res 2015; 26:79-81. [PMID: 26589199 DOI: 10.1007/s10286-015-0323-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 10/27/2015] [Indexed: 11/28/2022]
Abstract
Here we report the case of a patient with familial dysautonomia (a genetic form of afferent baroreflex failure), who had severe hypertension (230/149 mmHg) induced by the stress of his mother taking his blood pressure. His hypertension subsided when he learnt to measure his blood pressure without his mother's involvement. The case highlights how the reaction to maternal stress becomes amplified when catecholamine release is no longer under baroreflex control.
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Affiliation(s)
- Lucy Norcliffe-Kaufmann
- Dysautonomia Center, Department of Neurology, New York University, New York, NY, 10016, USA.
| | - Jose-Alberto Palma
- Dysautonomia Center, Department of Neurology, New York University, New York, NY, 10016, USA
| | - Horacio Kaufmann
- Dysautonomia Center, Department of Neurology, New York University, New York, NY, 10016, USA
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Fuente Mora C, Norcliffe-Kaufmann L, Palma JA, Kaufmann H. Chewing-induced hypertension in afferent baroreflex failure: a sympathetic response? Exp Physiol 2015; 100:1269-79. [PMID: 26435473 PMCID: PMC5074388 DOI: 10.1113/ep085340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/01/2015] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? Our goal was to understand the autonomic responses to eating in patients with congenital afferent baroreflex failure, by documenting changes in blood pressure and heart rate with chewing, swallowing and stomach distension. What is the main finding and its importance? Patients born with lesions in the afferent baroreceptor pathways have an exaggerated pressor response to food intake. This appears to be a sympathetically mediated response, triggered by chewing, that occurs independently of swallowing or distension of the stomach. The chewing-induced pressor response may be useful as a counter-manoeuvre to prevent orthostatic hypotension in these patients. Familial dysautonomia (FD) is a rare genetic disease with extremely labile blood pressure resulting from baroreflex deafferentation. Patients have marked surges in sympathetic activity, frequently surrounding meals. We conducted an observational study to document the autonomic responses to eating in patients with FD and to determine whether sympathetic activation was caused by chewing, swallowing or stomach distension. Blood pressure and R-R intervals were measured continuously while chewing gum (n = 15), eating (n = 20) and distending the stomach by percutaneous endoscopic gastrostomy tube feeding (n = 9). Responses were compared with those of normal control subjects (n = 10) and of patients with efferent autonomic failure (n = 10) who have chronically impaired sympathetic outflow. In patients with FD, eating was associated with a marked but transient pressor response (P < 0.0001) and additional signs of sympathetic activation, including tachycardia, diaphoresis and flushing of the skin. Chewing gum evoked a similar increase in blood pressure that was higher in patients with FD than in control subjects (P = 0.0001), but was absent in patients with autonomic failure. In patients with FD, distending the stomach by percutaneous endoscopic gastrostomy tube feeding failed to elicit a pressor response. The results provide indirect evidence that chewing triggers sympathetic activation. The increase in blood pressure is exaggerated in patients with FD as a result of blunted afferent baroreceptor signalling. The chewing pressor response may be useful as a counter-manoeuvre to raise blood pressure and prevent symptomatic orthostatic hypotension in patients with FD.
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Affiliation(s)
- Cristina Fuente Mora
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Jose-Alberto Palma
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
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Abstract
Neurogenic orthostatic hypotension (nOH) is a fall in blood pressure (BP) on standing due to reduced norepinephrine release from sympathetic nerve terminals. nOH is a feature of several neurological disorders that affect the autonomic nervous system, most notably Parkinson disease (PD), multiple system atrophy (MSA), pure autonomic failure (PAF), and other autonomic neuropathies. Droxidopa, an orally active synthetic amino acid that is converted to norepinephrine by the enzyme aromatic L-amino acid decarboxylase (dopa-decarboxylase), was recently approved by the FDA for the short-term treatment of nOH. It is presumed to raise BP by acting at the neurovascular junction to increase vascular tone. This article summarizes the pharmacological properties of droxidopa, its mechanism of action, and the efficacy and safety results of clinical trials.
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Affiliation(s)
- Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA
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32
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Jelani QUA, Norcliffe-Kaufmann L, Kaufmann H, Katz SD. Vascular endothelial function and blood pressure regulation in afferent autonomic failure. Am J Hypertens 2015; 28:166-72. [PMID: 25128693 DOI: 10.1093/ajh/hpu144] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Familial dysautonomia (FD) is a rare hereditary disease characterized by loss of afferent autonomic neural fiber signaling and consequent profound impairment of arterial baroreflex function and blood pressure regulation. Whether vascular endothelial dysfunction contributes to defective vasomotor control in this form of afferent autonomic failure is not known. METHODS We assessed blood pressure response to orthostatic stress and vascular endothelial function with brachial artery reactivity testing in 34 FD subjects with afferent autonomic failure and 34 healthy control subjects. RESULTS Forty-four percent of the afferent autonomic failure subjects had uncontrolled hypertension at supine rest (median systolic blood pressure = 148mm Hg, interquartile range (IQR) = 144-155mm Hg; median diastolic blood pressure = 83mm Hg, IQR = 78-105mm Hg), and 88% had abnormal response to orthostatic stress (median decrease in systolic blood pressure after upright tilt = 48mm Hg, IQR = 29-61mm Hg). Flow-mediated brachial artery reactivity did not differ in subjects with afferent autonomic failure vs. healthy control subjects (median = 6.00%, IQR = 1.86-11.77%; vs. median = 6.27%, IQR = 4.65-9.34%; P = 0.75). In afferent autonomic failure subjects, brachial artery reactivity was not associated with resting blood pressure or the magnitude of orthostatic hypotension but was decreased in association with reduced glomerular filtration rate (r = 0.62; P < 0.001). CONCLUSIONS Brachial artery reactivity was preserved in subjects with afferent autonomic failure despite the presence of marked blood pressure dysregulation. Comorbid renal dysfunction was associated with reduced brachial artery reactivity.
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Affiliation(s)
- Qurat-Ul-Ain Jelani
- Leon H. Charney Division of Cardiology, New York University School of Medicine, New York University Langone Medical Center, New York, New York
| | - Lucy Norcliffe-Kaufmann
- Dysautonomia Center, New York University School of Medicine, New York University Langone Medical Center, New York, New York
| | - Horacio Kaufmann
- Dysautonomia Center, New York University School of Medicine, New York University Langone Medical Center, New York, New York
| | - Stuart D Katz
- Leon H. Charney Division of Cardiology, New York University School of Medicine, New York University Langone Medical Center, New York, New York;
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Palma JA, Norcliffe-Kaufmann L, Fuente-Mora C, Percival L, Mendoza-Santiesteban C, Kaufmann H. Current treatments in familial dysautonomia. Expert Opin Pharmacother 2014; 15:2653-71. [PMID: 25323828 PMCID: PMC4236240 DOI: 10.1517/14656566.2014.970530] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (ELP-1) (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception result in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss. AREAS COVERED This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene-modifying agents. EXPERT OPINION Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to the risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression.
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Affiliation(s)
- Jose-Alberto Palma
- New York University School of Medicine, Dysautonomia Center, Department of Neurology , 530 First Avenue, Suite 9Q New York, NY 10016 , USA +1 212 263 7225 ;
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Karlsborn T, Tükenmez H, Chen C, Byström AS. Familial dysautonomia (FD) patients have reduced levels of the modified wobble nucleoside mcm5s2U in tRNA. Biochem Biophys Res Commun 2014; 454:441-5. [DOI: 10.1016/j.bbrc.2014.10.116] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 10/21/2014] [Indexed: 12/30/2022]
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Norcliffe-Kaufmann L, Kaufmann H. Is ambulatory blood pressure monitoring useful in patients with chronic autonomic failure? Clin Auton Res 2014; 24:189-92. [DOI: 10.1007/s10286-014-0229-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
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Affiliation(s)
- Christopher Cielo
- Division of Pulmonary Medicine, The Children's Hospital of Philadelphia, Colket Translational Research Building, 11th Floor Pulmonary Medicine, 3501 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Carole L Marcus
- Sleep Center, The Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, 9 Northwest 50 Main Building, 34th and Civic Center Boulevard, Philadelphia, PA 19104, USA
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Schroeder C, Jordan J, Kaufmann H. Management of neurogenic orthostatic hypotension in patients with autonomic failure. Drugs 2014; 73:1267-79. [PMID: 23857549 DOI: 10.1007/s40265-013-0097-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The maintenance of blood pressure in the upright position requires intact autonomic cardiovascular reflexes. Diseases that affect the sympathetic innervation of the cardiovascular system result in a sustained fall in blood pressure upon standing (i.e., neurogenic orthostatic hypotension) that can impair the blood supply to the brain and other organs and cause considerable morbidity and mortality. Here we review treatment options for neurogenic orthostatic hypotension and include an algorithm for its management that emphasizes the importance of non-pharmacologic measures and provides guidance on pharmacologic treatment options.
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Affiliation(s)
- Christoph Schroeder
- Institute of Clinical Pharmacology, OE 5350, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Germany.
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Norcliffe-Kaufmann L, Martinez J, Axelrod F, Kaufmann H. Hyperdopaminergic crises in familial dysautonomia: a randomized trial of carbidopa. Neurology 2013; 80:1611-7. [PMID: 23553478 DOI: 10.1212/wnl.0b013e31828f18f0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The purpose of this study was to determine whether carbidopa (Lodosyn), an inhibitor of dopa-decarboxylase that blocks the synthesis of dopamine outside the brain, is an effective antiemetic in patients with familial dysautonomia (FD) and hyperdopaminergic nausea/retching/vomiting attacks. METHODS We enrolled 12 patients with FD in an open-label titration and treatment study to assess the safety of carbidopa. We then conducted a randomized, double-blind, placebo-controlled, crossover study to evaluate its antiemetic efficacy. RESULTS Previous fundoplication surgery in each patient studied prevented vomiting, but all of the subjects experienced severe cyclical nausea and uncontrollable retching that was refractory to standard treatments. Carbidopa at an average daily dose of 480 mg (range 325-600 mg/day) was well tolerated. In the double-blind phase, patients experienced significantly less nausea and retching while on carbidopa than on placebo (p < 0.03 and p < 0.02, respectively). Twenty-four-hour urinary dopamine excretion was significantly lower while on carbidopa (147 ± 32 µg/gCr) than while on placebo (222 ± 41µg/gCr, p < 0.05). CONCLUSIONS Carbidopa is a safe and effective antiemetic in patients with FD, likely by reducing the formation of dopamine outside the brain. CLASSIFICATION OF EVIDENCE This study provides Class II evidence that carbidopa is effective in reducing nausea/retching/vomiting in patients with FD.
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Bochner R, Ziv Y, Zeevi D, Donyo M, Abraham L, Ashery-Padan R, Ast G. Phosphatidylserine increases IKBKAP levels in a humanized knock-in IKBKAP mouse model. Hum Mol Genet 2013; 22:2785-94. [PMID: 23515154 DOI: 10.1093/hmg/ddt126] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Familial dysautonomia (FD) is a severe neurodegenerative genetic disorder restricted to the Ashkenazi Jewish population. The most common mutation in FD patients is a T-to-C transition at position 6 of intron 20 of the IKBKAP gene. This mutation causes aberrant skipping of exon 20 in a tissue-specific manner, leading to reduction of the IκB kinase complex-associated protein (IKAP) protein in the nervous system. We established a homozygous humanized mouse strain carrying human exon 20 and its two flanking introns; the 3' intron has the transition observed in the IKBKAP gene of FD patients. Although our FD humanized mouse does not display FD symptoms, the unique, tissue-specific splicing pattern of the IKBKAP in these mice allowed us to evaluate the effect of therapies on gene expression and exon 20 splicing. The FD mice were supplemented with phosphatidylserine (PS), a safe food supplement that increases mRNA and protein levels of IKBKAP in cell lines generated from FD patients. Here we demonstrated that PS treatment increases IKBAKP mRNA and IKAP protein levels in various tissues of FD mice without affecting exon 20 inclusion levels. We also observed that genes associated with transcription regulation and developmental processes were up-regulated in the cerebrum of PS-treated mice. Thus, PS holds promise for the treatment of FD.
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Affiliation(s)
- Ron Bochner
- Department of Human Molecular Genetics and Biochemistry
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Abstract
Familial dysautonomia (FD) is a rare hereditary disorder caused by mutations within the gene that encodes for I-κ-B kinase complex associated protein (IKAP). A deficiency of IKAP affects the development of primary sensory neurons including those carrying baroreflex afferent volleys, a feature that explains their characteristic sensory loss and labile blood pressure. This review describes the history, the genotype of FD and the unusual cardiovascular autonomic phenotype of these patients. We outline the main consequences of a failure to receive information from arterial baroreceptors, including the characteristic "autonomic storms" and severe end-organ target damage.
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Dietrich P, Alli S, Shanmugasundaram R, Dragatsis I. IKAP expression levels modulate disease severity in a mouse model of familial dysautonomia. Hum Mol Genet 2012; 21:5078-90. [PMID: 22922231 DOI: 10.1093/hmg/dds354] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Hereditary sensory and autonomic neuropathies (HSANs) encompass a group of genetically inherited disorders characterized by sensory and autonomic dysfunctions. Familial dysautonomia (FD), also known as HSAN type III, is an autosomal recessive disorder that affects 1/3600 live births in the Ashkenazi Jewish population. The disease is caused by abnormal development and progressive degeneration of the sensory and autonomic nervous systems and is inevitably fatal, with only 50% of patients reaching the age of 40. FD is caused by a mutation in intron 20 of the Ikbkap gene that results in severe reduction in the expression of its encoded protein, inhibitor of kappaB kinase complex-associated protein (IKAP). Although the mutation that causes FD was identified in 2001, so far there is no appropriate animal model that recapitulates the disorder. Here, we report the generation and characterization of the first mouse models for FD that recapitulate the molecular and pathological features of the disease. Important for therapeutic interventions is also our finding that a slight increase in IKAP levels is enough to ameliorate the phenotype and increase the life span. Understanding the mechanisms underlying FD will provide insights for potential new therapeutic interventions not only for FD, but also for other peripheral neuropathies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN 38163, USA
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