Breathing disorders in Rett syndrome: Progressive neurochemical dysfunction in the respiratory network after birth

Katz, David M.; Dutschmann, Mathias; Ramirez, Jan‐Marino; Hilaire, Gérard

doi:10.1016/j.resp.2009.04.017

Cited by 164 publications

(136 citation statements)

References 106 publications

(147 reference statements)

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“…Several reasons could explain the lack of clinically significant effects of DMI on breathing patterns in RTT girls. First, as described by several authors, breathing dysfunction in RTT is very complex and highly variable 5, 6, 7, 8, 22. We monitored the breathing disorders in awake patients at each visit and found similar results on AHI to those reported in two patients with atypical Rett 23.…”

Section: Discussionsupporting

confidence: 58%

Effect of desipramine on patients with breathing disorders in RETT syndrome

Mancini

Dubus

Jouve

et al. 2017

Ann Clin Transl Neurol

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ObjectiveRett Syndrome (RTT) is a severe neurodevelopmental condition with breathing disorders, affecting around one in 10,000 female births. Desipramine, a noradrenaline reuptake inhibitor, reduced the number of apneas in Mecp2‐deficient mice, a model of RTT. We planned a phase 2 trial to test its efficacy and its safety on breathing patterns in 36 girls with RTT.MethodsThe trial was a 6‐month, multicenter, randomized, double‐blind, placebo‐controlled study registered with ClinicalTrials.gov, number NCT00990691. Girls diagnosed according to clinical examination and confirmed by genotyping were randomly assigned in a 1:1:1 ratio to receive 2–3 mg/kg Desipramine per day (high Desipramine), 1–2 mg/kg Desipramine per day (low Desipramine), or a placebo. The primary outcome was the change of apnea hypopnea index (AHI), defined by the number of apnea and hypopnea events per hour, assessed at 6 months from baseline. Intention‐to‐treat analysis was applied.ResultsThe median change in AHI from baseline to 6 months was −31 (IQR: −37 to −11) for the high Desipramine, −17.5 (IQR: −31 to 13) for the low Desipramine, and −13 (IQR:−31 to 0) for the placebo group. We did not find any significant difference in these changes between the groups (P = 0.781). A significant inverse correlation between Desipramine plasma concentration and AHI (r = −0.44; P = 0.0002) was underlined.InterpretationThis first clinical trial of desipramine did not show clinical efficacy. Although required further studies, the significant correlation between Desipramine concentrations and improvement of AHI provided additional and relevant reasons to test the noradrenergic pathway in RTT.

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Section: Discussionsupporting

confidence: 58%

Effect of desipramine on patients with breathing disorders in RETT syndrome

Mancini

Dubus

Jouve

et al. 2017

Ann Clin Transl Neurol

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“…These abnormalities are faithfully mimicked in mouse models of RTT (8). In Mecp2 null male animals studied in situ phrenic (PN) apneas were characterized by prolonged postinspiratory (post-I) activity in the central vagus nerve (9).…”

mentioning

confidence: 84%

Correction of respiratory disorders in a mouse model of Rett syndrome

Abdala

Dutschmann

Bissonnette

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Rett syndrome (RTT) is an autism spectrum disorder caused by mutations in the X-linked gene that encodes the transcription factor methyl-CpG-binding protein 2 (MeCP2). A major debilitating phenotype in affected females is frequent apneas, and heterozygous Mecp2-deficient female mice mimic the human respiratory disorder. GABA defects have been demonstrated in the brainstem of Mecp2-deficient mice. Here, using an intact respiratory network, we show that apnea in RTT mice is characterized by excessive excitatory activity in expiratory cranial and spinal nerves. Augmenting GABA markedly improves the respiratory phenotype. In addition, a serotonin 1a receptor agonist that depresses expiratory neuron activity also reduces apnea, corrects the irregular breathing pattern, and prolongs survival in MeCP2 null males. Combining a GABA reuptake blocker with a serotonin 1a agonist in heterozygous females completely corrects their respiratory defects. The results indicate that GABA and serotonin 1a receptor activity are candidates for treatment of the respiratory disorders in Rett syndrome.R ett syndrome (RTT) is an autism spectrum disorder that is caused by mutations in the X-linked gene that encodes methyl-CpG-binding protein 2 (MeCP2) (1). The role of this transcription factor is incompletely understood. Until recently, on the basis of animal studies primarily in embryonic or early neonatal brain, Mecp2 was considered a translational repressor (2, 3). Recently, however, Skene et al. (4) found in neuronal nuclei of mature (6-8 wk) WT littermates of Mecp2 null males that Mecp2 expression is ≈fivefold greater than that at birth. The amount of Mecp2 bound to DNA was proportional to the methylation density of CpG sequences. Importantly, in adult mice, it has been shown that restoring Mecp2 reverses the abnormalities in mobility, gait, hind limb clasping, tremor, breathing, and general condition that they developed during the period that the transcription factor was deficient (5). Thus, Mecp2 deficiency does not cause neuronal degeneration, nor is it necessary for the correct development of neuronal networks. Strategies aimed at pharmacological corrections of symptoms are therefore essential in treating RTT.Respiratory disorders are prominent and one of the most disturbing features of RTT (6, 7). These abnormalities are faithfully mimicked in mouse models of RTT (8). In Mecp2 null male animals studied in situ phrenic (PN) apneas were characterized by prolonged postinspiratory (post-I) activity in the central vagus nerve (9). Post-I activity is linked to the control of laryngeal adductors that control expiratory airflow and protect the lower airways from aspiration during swallowing. Active breath-hold with laryngeal closure is a common feature of RTT (6,7,10).This raises the possibility that the apneas are due to overactive brainstem expiratory neurons in Mecp2 heterozygote mice, perhaps consequent to a lack of synaptic inhibitory control. In this regard, examination of GABA synaptic inhibition in the ventrolateral medulla of Mec...

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“…While respiration has received more attention in animal studies [Katz et al, 2009] compared to cardiovascular function, there is a strong suggestion that insufficient GABA synaptic transmission may be a common thread that impairs the 2 neuronal systems [Lioy et al, 2011].…”

Section: Future Therapeutic Perspectivesmentioning

confidence: 99%

Rett Syndrome

2011

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Rett syndrome is one of the most common causes of complex disability in girls. It is characterized by early neurological regression that severely affects motor, cognitive and communication skills, by autonomic dysfunction and often a seizure disorder. It is a monogenic X-linked dominant neurodevelopmental disorder related to mutation in MECP2, which encodes the methyl-CpG-binding protein MeCP2. There are several mouse models either based on conditional knocking out of the Mecp2 gene or on a truncating mutation. We discuss the clinical aspects with special emphasis on the behavioral phenotype and we review current perspectives in clinical management alongside with perspectives in altering gene expression.

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Breathing disorders in Rett syndrome: Progressive neurochemical dysfunction in the respiratory network after birth

Cited by 164 publications

References 106 publications

Effect of desipramine on patients with breathing disorders in RETT syndrome

Effect of desipramine on patients with breathing disorders in RETT syndrome

Correction of respiratory disorders in a mouse model of Rett syndrome

Rett Syndrome

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