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Souza GMPR, Abbott SBG. Loss-of-function of chemoreceptor neurons in the retrotrapezoid nucleus: What have we learned from it? Respir Physiol Neurobiol 2024; 322:104217. [PMID: 38237884 PMCID: PMC10922619 DOI: 10.1016/j.resp.2024.104217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 01/11/2024] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
Central respiratory chemoreceptors are cells in the brain that regulate breathing in relation to arterial pH and PCO2. Neurons located at the retrotrapezoid nucleus (RTN) have been hypothesized to be central chemoreceptors and/or to be part of the neural network that drives the central respiratory chemoreflex. The inhibition or ablation of RTN chemoreceptor neurons has offered important insights into the role of these cells on central respiratory chemoreception and the neural control of breathing over almost 60 years since the original identification of acid-sensitive properties of this ventral medullary site. Here, we discuss the current definition of chemoreceptor neurons in the RTN and describe how this definition has evolved over time. We then summarize the results of studies that use loss-of-function approaches to evaluate the effects of disrupting the function of RTN neurons on respiration. These studies offer evidence that RTN neurons are indispensable for the central respiratory chemoreflex in mammals and exert a tonic drive to breathe at rest. Moreover, RTN has an interdependent relationship with oxygen sensing mechanisms for the maintenance of the neural drive to breathe and blood gas homeostasis. Collectively, RTN neurons are a genetically-defined group of putative central respiratory chemoreceptors that generate CO2-dependent drive that supports eupneic breathing and stimulates the hypercapnic ventilatory reflex.
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Lavezzi AM, Mehboob R, Piscioli F, Pusiol T. Involvement of the Superior Colliculus in SIDS Pathogenesis. Biomedicines 2023; 11:1689. [PMID: 37371784 DOI: 10.3390/biomedicines11061689] [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: 04/20/2023] [Revised: 05/25/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The aim of this study was to investigate the involvement of the mesencephalic superior colliculus (SC) in the pathogenetic mechanism of SIDS, a syndrome frequently ascribed to arousal failure from sleep. We analyzed the brains of 44 infants who died suddenly within the first 7 months of life, among which were 26 infants with SIDS and 18 controls. In-depth neuropathological investigations of serial sections of the midbrain showed the SC layered cytoarchitectural organization already well known in animals, as made up of seven distinct layers, but so far never highlighted in humans, albeit with some differences. In 69% of SIDS cases but never in the controls, we observed alterations of the laminar arrangement of the SC deep layers (precisely, an increased number of polygonal cells invading the superficial layers and an increased presence of intensely stained myelinated fibers). Since it has been demonstrated in experimental studies that the deep layers of the SC exert motor control including that of the head, their developmental disorder could lead to the failure of newborns who are in a prone position to resume regular breathing by moving their heads in the sleep-arousal phase. The SC anomalies highlighted here represent a new step in understanding the pathogenetic process that leads to SIDS.
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Affiliation(s)
- Anna M Lavezzi
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20122 Milan, Italy
| | - Riffat Mehboob
- Lahore Medical Research Center and LMRC Laboratories, LLP, Lahore 54000, Pakistan
| | - Francesco Piscioli
- Provincial Health Care Services, Institute of Pathology, Santa Maria del Carmine Hospital, 38068 Rovereto, Italy
| | - Teresa Pusiol
- Provincial Health Care Services, Institute of Pathology, Santa Maria del Carmine Hospital, 38068 Rovereto, Italy
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3
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Brendel VA, Schmeisser MJ, Schumann S. A morphometric analysis of the circumolivary fiber bundle of the human brainstem. Front Neuroanat 2022; 16:990862. [DOI: 10.3389/fnana.2022.990862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 10/28/2022] [Indexed: 11/17/2022] Open
Abstract
The circumolivary fiber bundle (CFB) is considered to be an anatomical variation, which can be found on the surface of the human medulla oblongata. The macroscopical fiber bundle runs downwards from either the anterior median fissure, the pyramid, or both, around the inferior pole of the olive and turns upwards to reach the restiform body of the inferior cerebellar peduncle. Multiple fiber systems feed the constitution of the CFB (collateral corticospinal fibers, fibers connecting to the reticular formation, anterior external arcuate fibers). With this examination we provide a systematic analysis of the frequency of occurrence (6.14%), size, and laterality of the CFB. Including all three fiber bundle parts (descending part, genu, and ascending part), the left-sided sizes were increased. Likewise, the appearance of an unilateral left-sided CFB could be detected in more than 60% of our cases. Our morphometrical analysis currently covers the largest sample of investigated brainstem sides (n = 489) so far. This investigation should widen the perspective on how anatomists, neuroradiologists, and neurosurgeons expect the anterolateral surface of the human medulla oblongata.
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Moon RY, Carlin RF, Hand I. Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths. Pediatrics 2022; 150:188305. [PMID: 35921639 DOI: 10.1542/peds.2022-057991] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Every year in the United States, approximately 3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths have remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. In addition, additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, which is included in this issue.
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Affiliation(s)
- Rachel Y Moon
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Rebecca F Carlin
- Division of Pediatric Critical Care and Hospital Medicine, Department of Pediatrics, Columbia University Irving Medical Center, NewYork-Presbyterian Hospital, New York City, New York
| | - Ivan Hand
- Department of Pediatrics, SUNY-Downstate College of Medicine, NYC Health + Hospitals, Kings County, Brooklyn, New York
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5
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Ueda A, Osawa M, Naito H, Ochiai E, Kakimoto Y. Non-polyalanine repeat mutation in PHOX2B is detected in autopsy cases of sudden unexpected infant death. PLoS One 2022; 17:e0267751. [PMID: 35486589 PMCID: PMC9053812 DOI: 10.1371/journal.pone.0267751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/15/2022] [Indexed: 11/18/2022] Open
Abstract
Background Congenital central hypoventilation syndrome (CCHS), which is caused by PHOX2B with phenotypic variations, has a point of controversy: CCHS is putatively involved in autopsy cases of sudden unexpected infant death (SUID) including sudden infant death syndrome. Objective The relation of CCHS to SUID cases was investigated by extensive genotyping of PHOX2B. Methods We analyzed 93 DNA samples of less than one-year-old SUID cases that were autopsied in our department. Unrelated adult volunteers (n = 942) were used as the control. Results No polyalanine tract expansion was detected in the SUID cases. The allelic frequencies of repeat contractions and SNP (rs28647582) in intron 2 were not significantly different from that in those control group. Further extensive sequencing revealed a non-polyalanine repeat mutation (NPARM) of c.905A>C in a sudden death case of a one-month-old male infant. This missense mutation (p.Asn302Thr), registered as rs779068107, was annotated to ‘Affected status is unknown’, but it might be associated with the sudden death. Conclusion NPARM was more plausibly related to sudden unexpected death than expansions because of severe clinical complications. This finding indicates possible CCHS involvement in forensic autopsy cases without ante-mortem diagnosis.
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Affiliation(s)
- Atsushi Ueda
- Department of Forensic Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Motoki Osawa
- Department of Forensic Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- * E-mail:
| | - Haruaki Naito
- Department of Forensic Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Eriko Ochiai
- Department of Forensic Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Department of Legal Medicine, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Yu Kakimoto
- Department of Forensic Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
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Ceccherini I, Kurek KC, Weese-Mayer DE. Developmental disorders affecting the respiratory system: CCHS and ROHHAD. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:53-91. [PMID: 36031316 DOI: 10.1016/b978-0-323-91532-8.00005-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) and Congenital Central Hypoventilation Syndrome (CCHS) are ultra-rare distinct clinical disorders with overlapping symptoms including altered respiratory control and autonomic regulation. Although both disorders have been considered for decades to be on the same spectrum with necessity of artificial ventilation as life-support, recent acquisition of specific knowledge concerning the genetic basis of CCHS coupled with an elusive etiology for ROHHAD have definitely established that the two disorders are different. CCHS is an autosomal dominant neurocristopathy characterized by alveolar hypoventilation resulting in hypoxemia/hypercarbia and features of autonomic nervous system dysregulation (ANSD), with presentation typically in the newborn period. It is caused by paired-like homeobox 2B (PHOX2B) variants, with known genotype-phenotype correlation but pathogenic mechanism(s) are yet unknown. ROHHAD is characterized by rapid weight gain, followed by hypothalamic dysfunction, then hypoventilation followed by ANSD, in seemingly normal children ages 1.5-7 years. Postmortem neuroanatomical studies, thorough clinical characterization, pathophysiological assessment, and extensive genetic inquiry have failed to identify a cause attributable to a traditional genetic basis, somatic mosaicism, epigenetic mechanism, environmental trigger, or other. To find the key to the ROHHAD pathogenesis and to improve its clinical management, in the present chapter, we have carefully compared CCHS and ROHHAD.
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Affiliation(s)
- Isabella Ceccherini
- Laboratory of Genetics and Genomics of Rare Diseases, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Kyle C Kurek
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Debra E Weese-Mayer
- Division of Autonomic Medicine, Department of Pediatrics, Ann & Robert H Lurie Children's Hospital of Chicago and Stanley Manne Children's Research Institute; and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.
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Neubauer J, Forst AL, Warth R, Both CP, Haas C, Thomas J. Genetic variants in eleven central and peripheral chemoreceptor genes in sudden infant death syndrome. Pediatr Res 2022; 92:1026-1033. [PMID: 35102300 PMCID: PMC9586864 DOI: 10.1038/s41390-021-01899-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/14/2021] [Accepted: 08/16/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Sudden infant death syndrome (SIDS) is still one of the leading causes of postnatal infant death in developed countries. The occurrence of SIDS is described by a multifactorial etiology that involves the respiratory control system including chemoreception. It is still unclear whether genetic variants in genes involved in respiratory chemoreception might play a role in SIDS. METHODS The exome data of 155 SIDS cases were screened for variants within 11 genes described in chemoreception. Pathogenicity of variants was assigned based on the assessment of variant types and in silico protein predictions according to the current recommendations of the American College of Medical Genetics and Genomics. RESULTS Potential pathogenic variants in genes encoding proteins involved in respiratory chemoreception could be identified in 5 (3%) SIDS cases. Two of the variants (R137S/A188S) were found in the KNCJ16 gene, which encodes for the potassium channel Kir5.1, presumably involved in central chemoreception. Electrophysiologic analysis of these KCNJ16 variants revealed a loss-of-function for the R137S variant but no obvious impairment for the A188S variant. CONCLUSIONS Genetic variants in genes involved in respiratory chemoreception may be a risk factor in a fraction of SIDS cases and may thereby contribute to the multifactorial etiology of SIDS. IMPACT What is the key message of your article? Gene variants encoding proteins involved in respiratory chemoreception may play a role in a minority of SIDS cases. What does it add to the existing literature? Although impaired respiratory chemoreception has been suggested as an important risk factor for SIDS, genetic variants in single genes seem to play a minor role. What is the impact? This study supports previous findings, which indicate that genetic variants in single genes involved in respiratory control do not have a dominant role in SIDS.
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Affiliation(s)
- Jacqueline Neubauer
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Anna-Lena Forst
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christian Peter Both
- grid.412341.10000 0001 0726 4330Department of Anesthesiology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Cordula Haas
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Jörg Thomas
- Department of Anesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.
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Baizer JS, Webster CJ, Witelson SF. Individual variability in the size and organization of the human arcuate nucleus of the medulla. Brain Struct Funct 2021; 227:159-176. [PMID: 34613435 DOI: 10.1007/s00429-021-02396-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022]
Abstract
The arcuate nucleus (Arc) of the medulla is found in almost all human brains and in a small percentage of chimpanzee brains. It is absent in the brains of other mammalian species including mice, rats, cats, and macaque monkeys. The Arc is classically considered a precerebellar relay nucleus, receiving input from the cerebral cortex and projecting to the cerebellum via the inferior cerebellar peduncle. However, several studies have found aplasia of the Arc in babies who died of SIDS (Sudden Infant Death Syndrome), and it was suggested that the Arc is the locus of chemosensory neurons critical for brainstem control of respiration. Aplasia of the Arc, however, has also been reported in adults, suggesting that it is not critical for survival. We have examined the Arc in closely spaced Nissl-stained sections in thirteen adult human cases to acquire a better understanding of the degree of variability of its size and location in adults. We have also examined immunostained sections to look for neurochemical compartments in this nucleus. Caudally, neurons of the Arc are ventrolateral to the pyramidal tracts (py); rostrally, they are ventro-medial to the py and extend up along the midline. In some cases, the Arc is discontinuous, with a gap between sections with the ventrolaterally located and the ventromedially located neurons. In all cases, there is some degree of left-right asymmetry in Arc position, size, and shape at all rostro-caudal levels. Somata of neurons in the Arc express calretinin (CR), neuronal nitric oxide synthase (nNOS), and nonphosphorylated neurofilament protein (NPNFP). Calbindin (CB) is expressed in puncta whereas there is no expression of parvalbumin (PV) in somata or puncta. There is also immunostaining for GAD and GABA receptors suggesting inhibitory input to Arc neurons. These properties were consistent among cases. Our data show differences in location of caudal and rostral Arc neurons and considerable variability among cases in the size and shape of the Arc. The variability in size suggests that "hypoplasia" of the Arc is difficult to define. The discontinuity of the Arc in many cases suggests that establishing aplasia of the Arc requires examination of many closely spaced sections through the brainstem.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, South Campus, Buffalo, NY, 14214, USA.
| | - Charles J Webster
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, South Campus, Buffalo, NY, 14214, USA
| | - Sandra F Witelson
- Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Levy J, Droz-Bartholet F, Achour M, Facchinetti P, Parratte B, Giuliano F. Parafacial neurons in the human brainstem express specific markers for neurons of the retrotrapezoid nucleus. J Comp Neurol 2021; 529:3313-3320. [PMID: 34008871 DOI: 10.1002/cne.25191] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/08/2021] [Accepted: 05/13/2021] [Indexed: 11/06/2022]
Abstract
The retrotrapezoid nucleus (RTN) is a hub for respiratory chemoregulation in the mammal brainstem that integrates chemosensory information from peripheral sites and central relays. Chemosensitive neurons of the RTN express specific genetic and molecular determinants, which have been used to identify RTN precise location within the brainstem of rodents and nonhuman primates. Based on a comparative approach, we hypothesized that among mammals, neurons exhibiting the same specific molecular and genetic signature would have the same function. The co-expression of preprogalanin (PPGAL) and SLC17A6 (VGluT2) mRNAs with duplex in situ hybridization has been studied in formalin fixed paraffin-embedded postmortem human brainstems. Two specimens were processed and analyzed in line with RTN descriptions in adult rats and macaques. Double-labeled PPGAL+/SLC17A6+ neurons were only identified in the parafacial region of the brainstem. These neurons were found surrounding the nucleus of the facial nerve, located ventrally to the nucleus VII on caudal sections, and slightly more dorsally on rostral sections. The expression of neuromedin B (NMB) mRNA as a single marker of chemosensitive RTN neurons has not been confirmed in humans. The location of the RTN in human adults is provided. This should help to develop investigation tools combining anatomic high-resolution imaging and respiratory functional investigations to explore the pathogenic role of the RTN in congenital or acquired neurodegenerative diseases.
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Affiliation(s)
- Jonathan Levy
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France.,Service de Médecine Physique et de Réadaptation - APHP, Hôpital Raymond Poincaré, Garches, France.,Fondation Garches - Hôpital Raymond Poincaré, Garches, France
| | - François Droz-Bartholet
- Laboratoire d'Anatomie - Faculté de Médecine de Besançon, Université de Franche-Comté, Besançon, France.,Service de Médecine Physique et de Réadaptation - CHRU Jean Minjoz, Besançon, France
| | - Melyna Achour
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France
| | - Patricia Facchinetti
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France
| | - Bernard Parratte
- Laboratoire d'Anatomie - Faculté de Médecine de Besançon, Université de Franche-Comté, Besançon, France.,Service de Médecine Physique et de Réadaptation - CHRU Jean Minjoz, Besançon, France
| | - François Giuliano
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France.,Service de Médecine Physique et de Réadaptation - APHP, Hôpital Raymond Poincaré, Garches, France
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Bachetti T, Bagnasco S, Piumelli R, Palmieri A, Ceccherini I. A Common 3'UTR Variant of the PHOX2B Gene Is Associated With Infant Life-Threatening and Sudden Death Events in the Italian Population. Front Neurol 2021; 12:642735. [PMID: 33815256 PMCID: PMC8017182 DOI: 10.3389/fneur.2021.642735] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Heterozygous mutations in the Paired like homeobox 2b (PHOX2B) gene are causative of congenital central hypoventilation syndrome (CCHS), a rare monogenic disorder belonging to the family of neurocristopathies and due to a defective development of the autonomic nervous system. Most patients manifest sudden symptoms within 1 year of birth, mainly represented by central apnea and cyanosis episodes. The sudden appearance of hypoxic manifestations in CCHS and their occurrence during sleep resemble two other unexplained perinatal disorders, apparent life-threatening event (ALTE) and sudden and unexpected infant death (SUID), among which the vast majority is represented by sudden infant death syndrome (SIDS). Differently from CCHS, characterized by Mendelian autosomal dominant inheritance, ALTE and SIDS are complex traits, where common genetic variants, together with external factors, may exert an additive effect with symptoms likely manifesting only over a “threshold.” Given the similarities observed among the three abovementioned perinatal disorders, in this work, we have analyzed the frequency of PHOX2B common variants in two groups of Italian idiopathic ALTE (IALTE) and SUIDs/SIDS patients. Here, we report that the c*161G>A (rs114290493) SNP of the 3′UTR PHOX2B (i) became overrepresented in the two sets of patients compared to population matched healthy controls, and (ii) associated with decreased PHOX2B gene expression, likely mediated by miR-204, a microRNA already known to bind the 3′UTR of the PHOX2B gene. Overall, these results suggest that, at least in the Italian population, the SNP c*161G>A (rs114290493) does contribute, presumably in association with others mutations or polymorphisms, to confer susceptibility to sudden unexplained perinatal life-threatening or fatal disorders by increasing the effect of miR-204 in inducing PHOX2B expression down-regulation. However, these are preliminary observations that need to be confirmed on larger cohorts to achieve a clinical relevance.
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Affiliation(s)
- Tiziana Bachetti
- Laboratorio di Neurobiologia dello Sviluppo, Dipartimento di Scienze della Terra, dell'Ambiente e della Vita (DISTAV), Università di Genova, Genoa, Italy.,Laboratorio di Genetica e Genomica delle Malattie Rare, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
| | - Simona Bagnasco
- Laboratorio di Genetica e Genomica delle Malattie Rare, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
| | - Raffaele Piumelli
- Centro per i Disturbi Respiratori nel Sonno-Centro Regionale SIDS, Ospedale Meyer, Florence, Italy
| | - Antonella Palmieri
- Dipartimento di Emergenza, Centro SIDS-ALTE, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
| | - Isabella Ceccherini
- Laboratorio di Genetica e Genomica delle Malattie Rare, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
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11
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Lei F, Wang W, Fu Y, Wang J, Zheng Y. Oxidative stress in retrotrapezoid nucleus/parafacial respiratory group and impairment of central chemoreception in rat offspring exposed to maternal cigarette smoke. Reprod Toxicol 2021; 100:35-41. [PMID: 33383163 DOI: 10.1016/j.reprotox.2020.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/16/2020] [Accepted: 12/19/2020] [Indexed: 02/05/2023]
Abstract
We have reported that smoking during pregnancy is associated with deficit in neonatal central chemoreception. However, the underlying mechanism is not well clarified. In this study, we developed a rat model of maternal cigarette smoke (CS) exposure. Pregnant rats were exposed to CS during gestational day 1-20. Offspring were studied on postnatal day 2. Reactive oxygen species (ROS) content and expressions of antioxidant proteins in retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) were examined by fluorogenic dye MitoSOX™ Red and Western blotting, respectively. The response of hypoglossal rootlets discharge to acidification was also detected with micro-injection of H2O2 into RTN/pFRG of offspring brainstem slices in vitro. Results showed that maternal CS exposure led to an increase in ROS production, and brought about decreases in mitochondrial superoxide dismutase and Kelch-like ECH-associated protein-1, and an increase in NF-E2-related factor 2 in offspring RTN/pFRG. Catalase and glutathione reductase expressions were not significantly changed. Moreover, oxidative stress induced by micro-injection of H2O2 into RTN/pFRG in vitro inhibited the discharge response of hypoglossal rootlets to acidification. These findings suggest that maternal CS exposure results in oxidative stress in RTN/pFRG of rat offspring, which might play a role in the impairment of central chemoreception.
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Affiliation(s)
- Fang Lei
- West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, PR China; Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan, PR China
| | - Wen Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan, PR China
| | - Yating Fu
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan, PR China
| | - Ji Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan, PR China
| | - Yu Zheng
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, Sichuan, PR China.
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12
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Di Lascio S, Benfante R, Cardani S, Fornasari D. Research Advances on Therapeutic Approaches to Congenital Central Hypoventilation Syndrome (CCHS). Front Neurosci 2021; 14:615666. [PMID: 33510615 PMCID: PMC7835644 DOI: 10.3389/fnins.2020.615666] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital central hypoventilation syndrome (CCHS) is a genetic disorder of neurodevelopment, with an autosomal dominant transmission, caused by heterozygous mutations in the PHOX2B gene. CCHS is a rare disorder characterized by hypoventilation due to the failure of autonomic control of breathing. Until now no curative treatment has been found. PHOX2B is a transcription factor that plays a crucial role in the development (and maintenance) of the autonomic nervous system, and in particular the neuronal structures involved in respiratory reflexes. The underlying pathogenetic mechanism is still unclear, although studies in vivo and in CCHS patients indicate that some neuronal structures may be damaged. Moreover, in vitro experimental data suggest that transcriptional dysregulation and protein misfolding may be key pathogenic mechanisms. This review summarizes latest researches that improved the comprehension of the molecular pathogenetic mechanisms responsible for CCHS and discusses the search for therapeutic intervention in light of the current knowledge about PHOX2B function.
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Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy.,CNR-Institute of Neuroscience, Milan, Italy.,NeuroMi-Milan Center for Neuroscience, University of Milano Bicocca, Milan, Italy
| | - Silvia Cardani
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy.,CNR-Institute of Neuroscience, Milan, Italy
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13
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Lei F, Wang W, Fu Y, Wang J, Zheng Y. Mitochondrial KATP channels contribute to the protective effects of hydrogen sulfide against impairment of central chemoreception of rat offspring exposed to maternal cigarette smoke. PLoS One 2020; 15:e0237643. [PMID: 33064729 PMCID: PMC7567348 DOI: 10.1371/journal.pone.0237643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/30/2020] [Indexed: 02/05/2023] Open
Abstract
We previously reported that maternal cigarette smoke (CS) exposure resulted in impairment of central chemoreception and induced mitochondrial dysfunction in offspring parafacial respiratory group (pFRG), the kernel for mammalian central chemoreception. We also found that hydrogen sulfide (H2S) could attenuate maternal CS exposure-induced impairment of central chemoreception in the rat offspring in vivo. Mitochondrial ATP sensitive potassium (mitoKATP) channel has been reported to play a significant role in mitochondrial functions and protect against apoptosis in neurons. Thus, we hypothesize here that mitoKATP channel plays a role in the protective effects of H2S on neonatal central chemoreception in maternal CS-exposed rats. Our findings revealed that pretreatment with NaHS (donor of H2S, 22.4mM) reversed the central chemosensitivity decreased by maternal CS exposure, and also inhibited cell apoptosis in offspring pFRG, however, 5-HD (blocker of mitoKATP channels, 19mM) attenuated the protective effects of NaHS. In addition, NaHS declined pro-apoptotic proteins related to mitochondrial pathway apoptosis in CS rat offspring pFRG, such as Bax, Cytochrome C, caspase9 and caspase3. NaHS or 5-HD alone had no significant effect on above indexes. These results suggest that mitoKATP channels play an important role in the protective effect of H2S against impairment of central chemoreception via anti-apoptosis in pFRG of rat offspring exposed to maternal CS.
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Affiliation(s)
- Fang Lei
- West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Wen Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Yating Fu
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Ji Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Yu Zheng
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, P.R. China
- * E-mail:
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Alzate-Correa D, Mei-Ling Liu J, Jones M, Silva TM, Alves MJ, Burke E, Zuñiga J, Kaya B, Zaza G, Aslan MT, Blackburn J, Shimada MY, Fernandes-Junior SA, Baer LA, Stanford KI, Kempton A, Smith S, Szujewski CC, Silbaugh A, Viemari JC, Takakura AC, Garcia AJ, Moreira TS, Czeisler CM, Otero JJ. Neonatal apneic phenotype in a murine congenital central hypoventilation syndrome model is induced through non-cell autonomous developmental mechanisms. Brain Pathol 2020; 31:84-102. [PMID: 32654284 PMCID: PMC7881415 DOI: 10.1111/bpa.12877] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 05/10/2020] [Accepted: 06/11/2020] [Indexed: 12/19/2022] Open
Abstract
Congenital central hypoventilation syndrome (CCHS) represents a rare genetic disorder usually caused by mutations in the homeodomain transcription factor PHOX2B. Some CCHS patients suffer mainly from deficiencies in CO2 and/or O2 respiratory chemoreflex, whereas other patients present with full apnea shortly after birth. Our goal was to identify the neuropathological mechanisms of apneic presentations in CCHS. In the developing murine neuroepithelium, Phox2b is expressed in three discrete progenitor domains across the dorsal-ventral axis, with different domains responsible for producing unique autonomic or visceral motor neurons. Restricting the expression of mutant Phox2b to the ventral visceral motor neuron domain induces marked newborn apnea together with a significant loss of visceral motor neurons, RTN ablation, and preBötzinger complex dysfunction. This finding suggests that the observed apnea develops through non-cell autonomous developmental mechanisms. Mutant Phox2b expression in dorsal rhombencephalic neurons did not generate significant respiratory dysfunction, but did result in subtle metabolic thermoregulatory deficiencies. We confirm the expression of a novel murine Phox2b splice variant which shares exons 1 and 2 with the more widely studied Phox2b splice variant, but which differs in exon 3 where most CCHS mutations occur. We also show that mutant Phox2b expression in the visceral motor neuron progenitor domain increases cell proliferation at the expense of visceral motor neuron development. We propose that visceral motor neurons may function as organizers of brainstem respiratory neuron development, and that disruptions in their development result in secondary/non-cell autonomous maldevelopment of key brainstem respiratory neurons.
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Affiliation(s)
- Diego Alzate-Correa
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jillian Mei-Ling Liu
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Mikayla Jones
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Talita M Silva
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Michele Joana Alves
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Elizabeth Burke
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jessica Zuñiga
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Behiye Kaya
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Giuliana Zaza
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Mehmet Tahir Aslan
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jessica Blackburn
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Marina Y Shimada
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Silvio A Fernandes-Junior
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Lisa A Baer
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kristin I Stanford
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Amber Kempton
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Sakima Smith
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Caroline C Szujewski
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Abby Silbaugh
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Jean-Charles Viemari
- P3M Team, Institut de Neurosciences de la Timone, UMR 7289 AMU-CNRS, Marseille, France
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Alfredo J Garcia
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Catherine M Czeisler
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - José J Otero
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
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15
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Patodia S, Paradiso B, Ellis M, Somani A, Sisodiya SM, Devinsky O, Thom M. Characterisation of medullary astrocytic populations in respiratory nuclei and alterations in sudden unexpected death in epilepsy. Epilepsy Res 2019; 157:106213. [PMID: 31610338 DOI: 10.1016/j.eplepsyres.2019.106213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 12/29/2022]
Abstract
Central failure of respiration during a seizure is one possible mechanism for sudden unexpected death in epilepsy (SUDEP). Neuroimaging studies indicate volume loss in the medulla in SUDEP and a post mortem study has shown reduction in neuromodulatory neuropeptidergic and monoaminergic neurones in medullary respiratory nuclear groups. Specialised glial cells identified in the medulla are considered essential for normal respiratory regulation including astrocytes with pacemaker properties in the pre-Botzinger complex and populations of subpial and perivascular astrocytes, sensitive to increased pCO2, that excite respiratory neurones. Our aim was to explore niches of medullary astrocytes in SUDEP cases compared to controls. In 48 brainstems from three groups, SUDEP (20), epilepsy controls (10) and non-epilepsy controls (18), sections through the medulla were labelled for GFAP, vimentin and functional markers, astrocytic gap junction protein connexin43 (Cx43) and adenosine A1 receptor (A1R). Regions including the ventro-lateral medulla (VLM; for the pre-Bötzinger complex), Median Raphe (MR) and lateral medullary subpial layer (MSPL) were quantified using image analysis for glial cell populations and compared between groups. Findings included morphologically and regionally distinct vimentin/Cx34-positive glial cells in the VLM and MR in close proximity to neurones. We noted a reduction of vimentin-positive glia in the VLM and MSPL and Cx43 glia in the MR in SUDEP cases compared to control groups (p < 0.05-0.005). In addition, we identified vimentin, Cx43 and A1R positive glial cells in the MSPL region which likely correspond to chemosensory glia identified experimentally. In conclusion, altered medullary glial cell populations could contribute to impaired respiratory regulatory capacity and vulnerability to SUDEP and warrant further investigation.
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Affiliation(s)
- Smriti Patodia
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Beatrice Paradiso
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Padua, Italy
| | - Matthew Ellis
- Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Alyma Somani
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Sanjay M Sisodiya
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Orrin Devinsky
- New York University School of Medicine, Comprehensive Epilepsy Center, New York, United States
| | - Maria Thom
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom.
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16
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Bachetti T, Ceccherini I. Causative and commonPHOX2Bvariants define a broad phenotypic spectrum. Clin Genet 2019; 97:103-113. [DOI: 10.1111/cge.13633] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/31/2019] [Accepted: 08/15/2019] [Indexed: 11/25/2022]
Affiliation(s)
- Tiziana Bachetti
- Laboratorio Neurobiologia dello Sviluppo, Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV)Università di Genova Genova Italy
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Levy J, Facchinetti P, Jan C, Achour M, Bouvier C, Brunet JF, Delzescaux T, Giuliano F. Tridimensional mapping of Phox2b expressing neurons in the brainstem of adult Macaca fascicularis and identification of the retrotrapezoid nucleus. J Comp Neurol 2019; 527:2875-2884. [PMID: 31071232 DOI: 10.1002/cne.24713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 11/08/2022]
Abstract
Chemosensitivity is a key mechanism for the regulation of breathing in vertebrates. The retrotrapezoid nucleus is a crucial hub for respiratory chemoreception within the brainstem. It integrates chemosensory information that are both peripheral from the carotid bodies (via the nucleus of the solitary tract) and central through the direct sensing of extracellular protons. To date, the location of a genetically defined RTN has only been ascertained in rodents. We first demonstrated that Phox2b, a key determinant for the development of the visceral nervous system and branchiomotor nuclei in the brainstem including the RTN, had a similar distribution in the brainstem of adult macaques compared to adult rats. Second, based on previous description of a specific molecular signature for the RTN in rats, and on an innovative technique for duplex in situ hybridization, we identified parafacial neurons which coexpressed Phox2b and ppGal mRNAs. They were located ventrally to the nucleus of the facial nerve and extended from the caudal part of the nucleus of the superior olive to the rostral tip of the inferior olive. Using the previously described blockface technique, deformations were corrected to allow the proper alignment and stacking of digitized sections, hence providing for the first time a 3D reconstruction of the macaque brainstem, Phox2b distribution and the primate retrotrapezoid nucleus. This description should help bridging the gap between rodents and humans for the description of key respiratory structures in the brainstem.
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Affiliation(s)
- Jonathan Levy
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France.,Service de Médecine Physique et de Réadaptation-APHP, Hôpital Raymond Poincaré, Garches, France.,Fondation Garches-APHP, Hôpital Raymond Poincaré, Garches, France
| | - Patricia Facchinetti
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Caroline Jan
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,CNRS-CEA UMR9199-Neurodegenerative Diseases Laboratory, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Mélyna Achour
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Clément Bouvier
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,NEOXIA, Paris, France
| | - Jean-François Brunet
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, Paris, France
| | - Thierry Delzescaux
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,CNRS-CEA UMR9199-Neurodegenerative Diseases Laboratory, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - François Giuliano
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France.,Service de Médecine Physique et de Réadaptation-APHP, Hôpital Raymond Poincaré, Garches, France
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18
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Giannakopoulou CE, Sotiriou A, Dettoraki M, Yang M, Perlikos F, Toumpanakis D, Prezerakos G, Koutsourelakis I, Kastis GA, Vassilakopoulou V, Mizi E, Papalois A, Greer JJ, Vassilakopoulos T. Regulation of breathing pattern by IL-10. Am J Physiol Regul Integr Comp Physiol 2019; 317:R190-R202. [PMID: 31091151 DOI: 10.1152/ajpregu.00065.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Proinflammatory cytokines like interleukin-1β (IL-1β) affect the control of breathing. Our aim is to determine the effect of the anti-inflammatory cytokine IL-10 οn the control of breathing. IL-10 knockout mice (IL-10-/-, n = 10) and wild-type mice (IL-10+/+, n = 10) were exposed to the following test gases: hyperoxic hypercapnia 7% CO2-93% O2, normoxic hypercapnia 7% CO2-21% O2, hypoxic hypercapnia 7% CO2-10% O2, and hypoxic normocapnia 3% CO2-10% O2. The ventilatory function was assessed using whole body plethysmography. Recombinant mouse IL-10 (rIL-10; 10 μg/kg) was administered intraperitoneally to wild-type mice (n = 10) 30 min before the onset of gas challenge. IL-10 was administered in neonatal medullary slices (10-30 ng/ml, n = 8). We found that IL-10-/- mice exhibited consistently increased frequency and reduced tidal volume compared with IL-10+/+ mice during room air breathing and in all test gases (by 23.62 to 33.2%, P < 0.05 and -36.23 to -41.69%, P < 0.05, respectively). In all inspired gases, the minute ventilation of IL-10-/- mice was lower than IL-10+/+ (by -15.67 to -22.74%, P < 0.05). The rapid shallow breathing index was higher in IL-10-/- mice compared with IL-10+/+ mice in all inspired gases (by 50.25 to 57.5%, P < 0.05). The intraperitoneal injection of rIL-10 caused reduction of the respiratory rate and augmentation of the tidal volume in room air and also in all inspired gases (by -12.22 to -29.53 and 32.18 to 45.11%, P < 0.05, respectively). IL-10 administration in neonatal rat (n = 8) in vitro rhythmically active medullary slice preparations did not affect either rhythmicity or peak amplitude of hypoglossal nerve discharge. In conclusion, IL-10 may induce a slower and deeper pattern of breathing.
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Affiliation(s)
- Charoula Eleni Giannakopoulou
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Adamantia Sotiriou
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Maria Dettoraki
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Michael Yang
- Experimental Research Center, ELPEN Pharmaceuticals, Attica, Greece
| | - Fotis Perlikos
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Dimitrios Toumpanakis
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Georgios Prezerakos
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Ioannis Koutsourelakis
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Georgios A Kastis
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Vyronia Vassilakopoulou
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | - Eleftheria Mizi
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
| | | | - John J Greer
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada
| | - Theodoros Vassilakopoulos
- Department of Critical Care and Pulmonary Services and Marianthi Simou Applied Biomedical Research and Training Center, University of Athens Medical School , Athens , Greece
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Yan X, Zhao F, Zhang S, Lei F, Wang W, Zheng Y. Hydrogen sulfide ameliorates disorders in the parafacial respiratory group region of neonatal rats caused by prenatal cigarette smoke exposure via an antioxidative effect. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 68:80-90. [PMID: 30878717 DOI: 10.1016/j.etap.2019.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 02/27/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
We previously found that hydrogen sulfide (H2S) ameliorated the dysfunction of central chemoreception caused by prenatal cigarette smoke exposure (CSE). In the present study, we further explored whether the parafacial respiratory group (pFRG) is involved in the protection of central chemoreception by H2S against prenatal CSE-induced injury. We found that NaHS, a donor of H2S, restored the expression of Phox2b, which was downregulated by prenatal CSE, in the pFRG region of neonatal rats. NaHS also relieved the prenatal CSE-induced excitatory synapse disturbance in the pFRG region of neonatal rats. Additionally, NaHS prevented the increase in the malondialdehyde level and suppression of antioxidase activity in the pFRG region of neonatal rats induced by prenatal CSE. Furthermore, NaHS prevented the downregulation of the expression of antioxidases and Nrf2 in the pFRG region of neonatal rats with prenatal CSE. These results suggest that H2S can protect the pFRG of neonatal rats against prenatal CSE-induced injury via an antioxidative effect.
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Affiliation(s)
- Xiang Yan
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041 Sichuan, PR China
| | - Fusheng Zhao
- Department of Physiology, Mudanjiang Medical University, Mudanjiang, 157011 Heilongjiang, PR China
| | - Senfeng Zhang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041 Sichuan, PR China
| | - Fang Lei
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041 Sichuan, PR China
| | - Wen Wang
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041 Sichuan, PR China
| | - Yu Zheng
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041 Sichuan, PR China.
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20
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Lavezzi AM, Poloniato A, Rovelli R, Lorioli L, Iasi GA, Pusiol T, Barera G, Ferrero S. Massive Amniotic Fluid Aspiration in a Case of Sudden Neonatal Death With Severe Hypoplasia of the Retrotrapezoid/Parafacial Respiratory Group. Front Pediatr 2019; 7:116. [PMID: 31019904 PMCID: PMC6458245 DOI: 10.3389/fped.2019.00116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/11/2019] [Indexed: 11/24/2022] Open
Abstract
We report a case of a baby, who, after pregnancy complicated by maternal Addison's disease and Hashimoto's thyroiditis and natural delivery, unexpectedly presented a cardiorespiratory collapse and died 1 hour after birth without responding to prolonged neonatal resuscitation maneuvers. The cause of death was reliably established by carrying out a forensic postmortem examination. More specifically, the histological examination of the lungs showed the presence of abundant endoalveolar and endobronchial cornea scales caused by absorption of amniotic fluid. The neuropathological examination of the brainstem highlighted severe hypodevelopment of the retrotrapezoid/parafacial respiratory group, which is a complex of neurons located in the caudal pons that is involved in respiratory rhythm coordination, especially expiration, in conditions of enhanced respiratory drive, as well as in chemoreception. This neuropathological finding shed new light on the mechanisms underlying the massive amniotic fluid aspiration which led to this early death.
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Affiliation(s)
- Anna M Lavezzi
- Department of Biomedical, Surgical and Dental Sciences, Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan, Milan, Italy
| | | | | | - Laura Lorioli
- Neonatal Unit, IRCCS Ospedale San Raffaele, Milan, Italy
| | | | - Teresa Pusiol
- Institute of Pathology, Hospital of Rovereto, Rovereto, Italy
| | | | - Stefano Ferrero
- Department of Biomedical, Surgical and Dental Sciences, Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan, Milan, Italy.,Division of Pathology, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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21
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Di Lascio S, Benfante R, Cardani S, Fornasari D. Advances in the molecular biology and pathogenesis of congenital central hypoventilation syndrome—implications for new therapeutic targets. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1540978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
- CNR- Neuroscience Institute, Milan, Italy
| | - Silvia Cardani
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
- CNR- Neuroscience Institute, Milan, Italy
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22
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Porzionato A, Macchi V, De Caro R. Central and peripheral chemoreceptors in sudden infant death syndrome. J Physiol 2018; 596:3007-3019. [PMID: 29645275 PMCID: PMC6068209 DOI: 10.1113/jp274355] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 03/20/2018] [Indexed: 11/08/2022] Open
Abstract
The pathogenesis of sudden infant death syndrome (SIDS) has been ascribed to an underlying biological vulnerability to stressors during a critical period of development. This paper reviews the main data in the literature supporting the role of central (e.g. retrotrapezoid nucleus, serotoninergic raphe nuclei, locus coeruleus, orexinergic neurons, ventral medullary surface, solitary tract nucleus) and peripheral (e.g. carotid body) chemoreceptors in the pathogenesis of SIDS. Clinical and experimental studies indicate that central and peripheral chemoreceptors undergo critical development during the initial postnatal period, consistent with the age range of SIDS (<1 year). Most of the risk factors for SIDS (gender, genetic factors, prematurity, hypoxic/hyperoxic stimuli, inflammation, perinatal exposure to cigarette smoke and/or substance abuse) may structurally and functionally affect the developmental plasticity of central and peripheral chemoreceptors, strongly suggesting the involvement of these structures in the pathogenesis of SIDS. Morphometric and neurochemical changes have been found in the carotid body and brainstem respiratory chemoreceptors of SIDS victims, together with functional signs of chemoreception impairment in some clinical studies. However, the methodological problems of SIDS research will have to be addressed in the future, requiring large and highly standardized case series. Up-to-date autopsy protocols should be produced, involving substantial, and exhaustive sampling of all potentially involved structures (including peripheral arterial chemoreceptors). Morphometric approaches should include unbiased stereological methods with three-dimensional probes. Prospective clinical studies addressing functional tests and risk factors (including genetic traits) would probably be the gold standard, allowing markers of intrinsic or acquired vulnerability to be properly identified.
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Affiliation(s)
- Andrea Porzionato
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
| | - Veronica Macchi
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
| | - Raffaele De Caro
- Section of Anatomy, Department of NeuroscienceUniversity of PadovaItaly
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23
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Ventura F, Barranco R, Bachetti T, Nozza P, Fulcheri E, Palmieri A, Ceccherini I. Medico-legal investigation in an explicable case of congenital central hypoventilation syndrome due to a rare variant of the PHOX2B gene. J Forensic Leg Med 2018; 58:1-5. [PMID: 29679838 DOI: 10.1016/j.jflm.2018.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 04/09/2018] [Accepted: 04/13/2018] [Indexed: 11/17/2022]
Abstract
The heterozygous PHOX2B gene mutation is related to congenital central hypoventilation syndrome (CCHS). It is characterized by defective autonomous nervous system development leading to inadequate breathing response to hypoxia and hypercapnia, leading to hypoventilation especially during non-REM sleep, but also during waking in the more severe cases. Herein we report a case of sudden death in a 28-day-old child. The mother reported the infant was found lying on her own bed in the prone position. The infant was wearing a romper and lying in her crib without any blanket or other objects. At autopsy no significant pathological findings were detected. Histologically, sparse aspirated milk residues were present in some lung fields. Toxicological and microbiological examinations were within the norm. The initial postmortem investigation ruled out any readily identifiable cause of death. However, genetic analysis revealed a rare heterozygous 21bp in-frame deletion of the polyalanine coding sequences of the PHOX2B gene. In-frame contractions of the poly-Ala tract of the PHOX2B gene have already been reported in patients with symptoms suggestive of sporadic hypoventilation, apparent life-threatening events or neonatal respiratory distress.
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Affiliation(s)
- Francesco Ventura
- Department of Forensic and Legal Medicine, University of Genova, Via De' Toni 12, 16132 Genova, Italy.
| | - Rosario Barranco
- Department of Forensic and Legal Medicine, University of Genova, Via De' Toni 12, 16132 Genova, Italy
| | - Tiziana Bachetti
- U.O.C. Medical Genetics, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy
| | - Paolo Nozza
- U.O.C. Clinical Pathology, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy
| | - Ezio Fulcheri
- U.O.S.D. Fetal and Perinatal Pathology, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy; School of Medicine, University of Genova, Italy
| | - Antonella Palmieri
- Department of Pediatric Emergency - Sudden Infant Death Syndrome Liguria Centre, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy
| | - Isabella Ceccherini
- U.O.C. Medical Genetics, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy
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24
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Coghlan M, Richards E, Shaik S, Rossi P, Vanama RB, Ahmadi S, Petroz C, Crawford M, Maynes JT. Inhalational Anesthetics Induce Neuronal Protein Aggregation and Affect ER Trafficking. Sci Rep 2018; 8:5275. [PMID: 29588456 PMCID: PMC5869676 DOI: 10.1038/s41598-018-23335-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 03/07/2018] [Indexed: 12/27/2022] Open
Abstract
Anesthetic agents have been implicated in the causation of neurological and cognitive deficits after surgery, the exacerbation of chronic neurodegenerative disease, and were recently reported to promote the onset of the neurologic respiratory disease Congenital Central Hypoventilation Syndrome (CCHS), related to misfolding of the transcription factor Phox2B. To study how anesthetic agents could affect neuronal function through alterations to protein folding, we created neuronal cell models emulating the graded disease severity of CCHS. We found that the gas anesthetic isoflurane and the opiate morphine potentiated aggregation and mislocalization of Phox2B variants, similar to that seen in CCHS, and observed transcript and protein level changes consistent with activation of the endoplasmic reticulum (ER) unfolded protein response. Attenuation of ER stress pathways did not result in a correction of Phox2B misfolding, indicating a primary effect of isoflurane on protein structure. We also observed that isoflurane hindered the folding and activity of proteins that rely heavily on ER function, like the CFTR channel. Our results show how anesthetic drugs can alter protein folding and induce ER stress, indicating a mechanism by which these agents may affect neuronal function after surgery.
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Affiliation(s)
- Matthew Coghlan
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Elizabeth Richards
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Sadiq Shaik
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Pablo Rossi
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Ramesh Babu Vanama
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Saumel Ahmadi
- Program in Molecular Medicine, SickKids Research Institute, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
| | - Christelle Petroz
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada
| | - Mark Crawford
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Anesthesia, University of Toronto, Toronto, Canada
| | - Jason T Maynes
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Canada. .,Department of Anesthesia, University of Toronto, Toronto, Canada. .,Program in Molecular Medicine, SickKids Research Institute, Toronto, Canada.
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25
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Loiseau C, Cayetanot F, Joubert F, Perrin-Terrin AS, Cardot P, Fiamma MN, Frugiere A, Straus C, Bodineau L. Current Perspectives for the use of Gonane Progesteronergic Drugs in the Treatment of Central Hypoventilation Syndromes. Curr Neuropharmacol 2018; 16:1433-1454. [PMID: 28721821 PMCID: PMC6295933 DOI: 10.2174/1570159x15666170719104605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/30/2017] [Accepted: 07/12/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Central alveolar hypoventilation syndromes (CHS) encompass neurorespiratory diseases resulting from congenital or acquired neurological disorders. Hypercapnia, acidosis, and hypoxemia resulting from CHS negatively affect physiological functions and can be lifethreatening. To date, the absence of pharmacological treatment implies that the patients must receive assisted ventilation throughout their lives. OBJECTIVE To highlight the relevance of determining conditions in which using gonane synthetic progestins could be of potential clinical interest for the treatment of CHS. METHODS The mechanisms by which gonanes modulate the respiratory drive were put into the context of those established for natural progesterone and other synthetic progestins. RESULTS The clinical benefits of synthetic progestins to treat respiratory diseases are mixed with either positive outcomes or no improvement. A benefit for CHS patients has only recently been proposed. We incidentally observed restoration of CO2 chemosensitivity, the functional deficit of this disease, in two adult CHS women by desogestrel, a gonane progestin, used for contraception. This effect was not observed by another group, studying a single patient. These contradictory findings are probably due to the complex nature of the action of desogestrel on breathing and led us to carry out mechanistic studies in rodents. Our results show that desogestrel influences the respiratory command by modulating the GABAA and NMDA signaling in the respiratory network, medullary serotoninergic systems, and supramedullary areas. CONCLUSION Gonanes show promise for improving ventilation of CHS patients, although the conditions of their use need to be better understood.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Laurence Bodineau
- Address correspondence to this author at the Sorbonne Universités, UPMC Univ. Paris 06, INSERM, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75013, Paris, France; Tel: 33 1 40 77 97 15; Fax: 33 1 40 77 97 89; E-mail:
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26
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Mehboob R, Kabir M, Ahmed N, Ahmad FJ. Towards Better Understanding of the Pathogenesis of Neuronal Respiratory Network in Sudden Perinatal Death. Front Neurol 2017; 8:320. [PMID: 28729852 PMCID: PMC5498558 DOI: 10.3389/fneur.2017.00320] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/19/2017] [Indexed: 01/16/2023] Open
Abstract
Sudden perinatal death that includes the victims of sudden infant death syndrome, sudden intrauterine death syndrome, and stillbirth are heartbreaking events in the life of parents. Most of the studies about sudden perinatal death were reported from Italy, highlighting two main etiological factors: prone sleeping position and smoking. Other probable contributory factors are prematurity, male gender, lack of breastfeeding, respiratory tract infections, use of pacifiers, infant botulism, extensive use of pesticides and insecticides, etc. However, extensive studies across the world are required to establish the role of these factors in a different subset of populations. Previous studies confirmed the widely accepted hypothesis that neuropathology of the brainstem is one of the main cause of sudden perinatal death. This study is an effort to summarize the neuropathological evaluation of the brainstems and their association to sudden perinatal death. Brainstem nuclei in vulnerable infants undergo certain changes that may alter the sleep arousal cycle, cardiorespiratory control, and ultimately culminate in death. This review focuses on the roles of different brainstem nuclei, their pathologies, and the established facts in this regard in terms of it's link to such deaths. This study will also help to understand the role of brainstem nuclei in controlling the cardiorespiratory cycles in sudden perinatal death and may provide a better understanding to resolve the mystery of these deaths in future. It is also found that a global initiative to deal with perinatal death is required to facilitate the diagnosis and prevention in developed and as well as developing countries.
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Affiliation(s)
- Riffat Mehboob
- Biomedical Sciences, King Edward Medical University, Lahore, Pakistan.,Faculty of Allied Health Sciences, University of Lahore, Lahore, Pakistan
| | - Mahvish Kabir
- Department of Chemistry, School of Science, University of Management and Technology (UMT), Lahore, Pakistan
| | - Naseer Ahmed
- Department of Cardiac Surgery, University of Verona Medical School, Verona, Italy.,Section of Pharmacology, University of Verona Medical School, Verona, Italy
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27
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Jaster J. Medullary neuropathology in sleep apnoea. Respirology 2017; 22:829. [DOI: 10.1111/resp.12994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/13/2016] [Indexed: 11/30/2022]
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28
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Congenital central hypoventilation syndrome: a bedside-to-bench success story for advancing early diagnosis and treatment and improved survival and quality of life. Pediatr Res 2017; 81:192-201. [PMID: 27673423 DOI: 10.1038/pr.2016.196] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/15/2016] [Indexed: 01/13/2023]
Abstract
The "bedside-to-bench" Congenital Central Hypoventilation Syndrome (CCHS) research journey has led to increased phenotypic-genotypic knowledge regarding autonomic nervous system (ANS) regulation, and improved clinical outcomes. CCHS is a neurocristopathy characterized by hypoventilation and ANS dysregulation. Initially described in 1970, timely diagnosis and treatment remained problematic until the first large cohort report (1992), delineating clinical presentation and treatment options. A central role of ANS dysregulation (2001) emerged, precipitating evaluation of genes critical to ANS development, and subsequent 2003 identification of Paired-Like Homeobox 2B (PHOX2B) as the disease-defining gene for CCHS. This breakthrough engendered clinical genetic testing, making diagnosis exact and early tracheostomy/artificial ventilation feasible. PHOX2B genotype-CCHS phenotype relationships were elucidated, informing early recognition and timely treatment for phenotypic manifestations including Hirschsprung disease, prolonged sinus pauses, and neural crest tumors. Simultaneously, cellular models of CCHS-causing PHOX2B mutations were developed to delineate molecular mechanisms. In addition to new insights regarding genetics and neurobiology of autonomic control overall, new knowledge gained has enabled physicians to anticipate and delineate the full clinical CCHS phenotype and initiate timely effective management. In summary, from an initial guarantee of early mortality or severe neurologic morbidity in survivors, CCHS children can now be diagnosed early and managed effectively, achieving dramatically improved quality of life as adults.
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29
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Alfonsi G, Crippa M. Updates on the Methodological Approaches for Carrying Out an In-Depth Study of the Cardiac Conduction System and the Autonomic Nervous System of Victims of Sudden Unexplained Fetal and Infant Death. Front Med (Lausanne) 2016; 3:54. [PMID: 27917382 PMCID: PMC5116575 DOI: 10.3389/fmed.2016.00054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/27/2016] [Indexed: 11/17/2022] Open
Abstract
This article contains a set of protocols for histopathological techniques that can be used for carrying out in-depth studies of cases of sudden infant death syndrome and sudden intrauterine unexplained fetal death syndrome. In order to enable researchers to advance hypotheses regarding the causes of the unexpected death of infants and fetuses, the authors propose three innovative and accurate methodologies for studying the cardiac conduction system, the peripheral cardiac nervous system, and the central autonomic nervous system. Over the years, these protocols have been developed, modified, and improved on a vast number of cases which has enabled pathologists to carry out the microscopic analyses of the structures which regulate life, in order to highlight all the possible morphological substrates of pathophysiological mechanisms that may underlie these syndromes. In memory of our research professor Lino Rossi (1923–2004).
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Affiliation(s)
- Graziella Alfonsi
- Department of Biomedical, Surgical and Dental Sciences, "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan , Milan , Italy
| | - Marina Crippa
- Service of Laboratory Medicine, Section of Pathological Anatomy, Department of Emergency, Clinica San Carlo , Paderno Dugnano , Italy
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30
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Moon RY. SIDS and Other Sleep-Related Infant Deaths: Evidence Base for 2016 Updated Recommendations for a Safe Infant Sleeping Environment. Pediatrics 2016; 138:peds.2016-2940. [PMID: 27940805 DOI: 10.1542/peds.2016-2940] [Citation(s) in RCA: 350] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Approximately 3500 infants die annually in the United States from sleep-related infant deaths, including sudden infant death syndrome (SIDS), ill-defined deaths, and accidental suffocation and strangulation in bed. After an initial decrease in the 1990s, the overall sleep-related infant death rate has not declined in more recent years. Many of the modifiable and nonmodifiable risk factors for SIDS and other sleep-related infant deaths are strikingly similar. The American Academy of Pediatrics recommends a safe sleep environment that can reduce the risk of all sleep-related infant deaths. Recommendations for a safe sleep environment include supine positioning, use of a firm sleep surface, room-sharing without bed-sharing, and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include avoidance of exposure to smoke, alcohol, and illicit drugs; breastfeeding; routine immunization; and use of a pacifier. New evidence and rationale for recommendations are presented for skin-to-skin care for newborn infants, bedside and in-bed sleepers, sleeping on couches/armchairs and in sitting devices, and use of soft bedding after 4 months of age. In addition, expanded recommendations for infant sleep location are included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, "SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment," which is included in this issue.
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31
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Abstract
Recent advances have clarified how the brain detects CO2 to regulate breathing (central respiratory chemoreception). These mechanisms are reviewed and their significance is presented in the general context of CO2/pH homeostasis through breathing. At rest, respiratory chemoreflexes initiated at peripheral and central sites mediate rapid stabilization of arterial PCO2 and pH. Specific brainstem neurons (e.g., retrotrapezoid nucleus, RTN; serotonergic) are activated by PCO2 and stimulate breathing. RTN neurons detect CO2 via intrinsic proton receptors (TASK-2, GPR4), synaptic input from peripheral chemoreceptors and signals from astrocytes. Respiratory chemoreflexes are arousal state dependent whereas chemoreceptor stimulation produces arousal. When abnormal, these interactions lead to sleep-disordered breathing. During exercise, central command and reflexes from exercising muscles produce the breathing stimulation required to maintain arterial PCO2 and pH despite elevated metabolic activity. The neural circuits underlying central command and muscle afferent control of breathing remain elusive and represent a fertile area for future investigation.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA
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32
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Nobuta H, Cilio MR, Danhaive O, Tsai HH, Tupal S, Chang SM, Murnen A, Kreitzer F, Bravo V, Czeisler C, Gokozan HN, Gygli P, Bush S, Weese-Mayer DE, Conklin B, Yee SP, Huang EJ, Gray PA, Rowitch D, Otero JJ. Dysregulation of locus coeruleus development in congenital central hypoventilation syndrome. Acta Neuropathol 2015; 130:171-83. [PMID: 25975378 PMCID: PMC4503865 DOI: 10.1007/s00401-015-1441-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/01/2015] [Accepted: 05/02/2015] [Indexed: 12/29/2022]
Abstract
Human congenital central hypoventilation syndrome (CCHS), resulting from mutations in transcription factor PHOX2B, manifests with impaired responses to hypoxemia and hypercapnia especially during sleep. To identify brainstem structures developmentally affected in CCHS, we analyzed two postmortem neonatal-lethal cases with confirmed polyalanine repeat expansion (PARM) or Non-PARM (PHOX2B∆8) mutation of PHOX2B. Both human cases showed neuronal losses within the locus coeruleus (LC), which is important for central noradrenergic signaling. Using a conditionally active transgenic mouse model of the PHOX2B∆8 mutation, we found that early embryonic expression (<E10.5) caused failure of LC neuronal specification and perinatal respiratory lethality. In contrast, later onset (E11.5) of PHOX2B∆8 expression was not deleterious to LC development and perinatal respiratory lethality was rescued, despite failure of chemosensor retrotrapezoid nucleus formation. Our findings indicate that early-onset mutant PHOX2B expression inhibits LC neuronal development in CCHS. They further suggest that such mutations result in dysregulation of central noradrenergic signaling, and therefore, potential for early pharmacologic intervention in humans with CCHS.
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33
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Poetsch M, Todt R, Vennemann M, Bajanowski T. That's not it, either-neither polymorphisms in PHOX2B nor in MIF are involved in sudden infant death syndrome (SIDS). Int J Legal Med 2015; 129:985-9. [PMID: 26104808 DOI: 10.1007/s00414-015-1213-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/03/2015] [Indexed: 11/30/2022]
Abstract
The occurrence of sudden infant death syndrome (SIDS) has been linked to several genetic risk factors, e.g. genes involved in the neuroadrenergic system, variations in serotonin reporter genes or mutations in long-QT syndrome genes. Additionally, polymorphisms in genes with impact in sleep disorder syndromes have been proposed to be of importance as genetic risk factors for SIDS. In this study, we investigated the polyalanine length variation of PHOX2B and the -794 CATT repeat in the MIF promoter region as well as single nucleotide polymorphisms (rs28462174, rs28727473, rs16853571, rs755622, rs12485058, rs12485068, rs4822444, rs4822445, rs4822446, rs4822447 and rs2012124) in both genes in 278 SIDS cases and 240 controls. No significant differences were found in allele distribution of neither length polymorphisms nor single nucleotide polymorphisms between SIDS cases or controls. Therefore, an importance of these variations for the occurrence of SIDS could be ruled out.
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Affiliation(s)
- Micaela Poetsch
- Institute of Legal Medicine, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany,
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34
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Lavezzi AM, Cappiello A, Pusiol T, Corna MF, Termopoli V, Matturri L. Pesticide exposure during pregnancy, like nicotine, affects the brainstem α7 nicotinic acetylcholine receptor expression, increasing the risk of sudden unexplained perinatal death. J Neurol Sci 2014; 348:94-100. [PMID: 25433450 DOI: 10.1016/j.jns.2014.11.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/24/2014] [Accepted: 11/10/2014] [Indexed: 12/16/2022]
Abstract
This study indicates the impact of nicotine and pesticides (organochlorine and organophosphate insecticides used in agriculture) on neuronal α7-nicotinic acetylcholine receptor expression in brainstem regions receiving cholinergic projections in human perinatal life. An in-depth anatomopathological examination of the autonomic nervous system and immunohistochemistry to analyze the α7-nicotinic acetylcholine receptor expression in the brainstem from 44 fetuses and newborns were performed. In addition, the presence of selected agricultural pesticides in cerebral cortex samples of the victims was determined by specific analytical procedures. Hypodevelopment of brainstem structures checking the vital functions, frequently associated with α7-nicotinic acetylcholine receptor immunopositivity and smoke absorption in pregnancy, was observed in high percentages of victims of sudden unexpected perinatal death. In nearly 30% of cases however the mothers never smoked, but lived in rural areas. The search for pesticides highlighted in many of these cases traces of both organochlorine and organophosphate pesticides. We detain that exposition to pesticides in pregnancy produces homologous actions to those of nicotine on neuronal α7-nicotinic acetylcholine receptor, allowing to developmental alterations of brainstem vital centers in victims of sudden unexplained death.
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Affiliation(s)
- Anna Maria Lavezzi
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Italy.
| | | | - Teresa Pusiol
- Institute of Anatomic Pathology, Hospital of Rovereto (Trento), Italy
| | - Melissa Felicita Corna
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Italy
| | | | - Luigi Matturri
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Italy
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35
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Abstract
Lung ventilation fluctuates widely with behavior but arterial PCO2 remains stable. Under normal conditions, the chemoreflexes contribute to PaCO2 stability by producing small corrective cardiorespiratory adjustments mediated by lower brainstem circuits. Carotid body (CB) information reaches the respiratory pattern generator (RPG) via nucleus solitarius (NTS) glutamatergic neurons which also target rostral ventrolateral medulla (RVLM) presympathetic neurons thereby raising sympathetic nerve activity (SNA). Chemoreceptors also regulate presympathetic neurons and cardiovagal preganglionic neurons indirectly via inputs from the RPG. Secondary effects of chemoreceptors on the autonomic outflows result from changes in lung stretch afferent and baroreceptor activity. Central respiratory chemosensitivity is caused by direct effects of acid on neurons and indirect effects of CO2 via astrocytes. Central respiratory chemoreceptors are not definitively identified but the retrotrapezoid nucleus (RTN) is a particularly strong candidate. The absence of RTN likely causes severe central apneas in congenital central hypoventilation syndrome. Like other stressors, intense chemosensory stimuli produce arousal and activate circuits that are wake- or attention-promoting. Such pathways (e.g., locus coeruleus, raphe, and orexin system) modulate the chemoreflexes in a state-dependent manner and their activation by strong chemosensory stimuli intensifies these reflexes. In essential hypertension, obstructive sleep apnea and congestive heart failure, chronically elevated CB afferent activity contributes to raising SNA but breathing is unchanged or becomes periodic (severe CHF). Extreme CNS hypoxia produces a stereotyped cardiorespiratory response (gasping, increased SNA). The effects of these various pathologies on brainstem cardiorespiratory networks are discussed, special consideration being given to the interactions between central and peripheral chemoreflexes.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
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36
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PHOX2B polyalanine repeat length is associated with sudden infant death syndrome and unclassified sudden infant death in the Dutch population. Int J Legal Med 2014; 128:621-9. [PMID: 24442913 DOI: 10.1007/s00414-013-0962-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
Unclassified sudden infant death (USID) is the sudden and unexpected death of an infant that remains unexplained after thorough case investigation including performance of a complete autopsy and review of the circumstances of death and the clinical history. When the infant is below 1 year of age and with onset of the fatal episode apparently occurring during sleep, this is referred to as sudden infant death syndrome (SIDS). USID and SIDS remain poorly understood despite the identification of several environmental and some genetic risk factors. In this study, we investigated genetic risk factors involved in the autonomous nervous system in 195 Dutch USID/SIDS cases and 846 Dutch, age-matched healthy controls. Twenty-five DNA variants from 11 genes previously implicated in the serotonin household or in the congenital central hypoventilation syndrome, of which some have been associated with SIDS before, were tested. Of all DNA variants considered, only the length variation of the polyalanine repeat in exon 3 of the PHOX2B gene was found to be statistically significantly associated with USID/SIDS in the Dutch population after multiple test correction. Interestingly, our data suggest that contraction of the PHOX2B exon 3 polyalanine repeat that we found in six of 160 SIDS and USID cases and in six of 814 controls serves as a probable genetic risk factor for USID/SIDS at least in the Dutch population. Future studies are needed to confirm this finding and to understand the functional effect of the polyalanine repeat length variation, in particular contraction, in exon 3 of the PHOX2B gene.
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Carroll MS, Patwari PP, Kenny AS, Brogadir CD, Stewart TM, Weese-Mayer DE. Residual chemosensitivity to ventilatory challenges in genotyped congenital central hypoventilation syndrome. J Appl Physiol (1985) 2013; 116:439-50. [PMID: 24381123 DOI: 10.1152/japplphysiol.01310.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Congenital central hypoventilation syndrome (CCHS) is a neurodevelopmental disorder characterized by life-threatening hypoventilation, possibly resulting from disruption of central chemosensory integration. However, animal models suggest the possibility of residual chemosensory function in the human disease. Cardioventilatory function in a large cohort with CCHS and verified paired-like homeobox 2B (PHOX2B) mutations was assessed to determine the extent and genotype dependence of any residual chemosensory function in these patients. As part of inpatient clinical care and evaluation, 64 distinct studies from 32 infants, children, and young adults with the disorder were evaluated for physiological response to three different inspired steady-state gas exposures of 3 min each: hyperoxia [100% oxygen (O2)]; hyperoxic hypercapnia [95% O2 and 5% carbon dioxide (CO2)]; and hypoxic hypercapnia [14% O2 and 7% CO2 balanced with nitrogen (N2)]. These were followed by a hypoxia challenge consisting of five or seven breaths of N2 (100% N2). In addition, a control group of 15 young adults was exposed to all but the hypoxic challenge. Comprehensive monitoring was used to derive breath-to-breath and beat-to-beat measures of ventilatory, cardiovascular, and cerebrovascular function. On average, patients showed a residual awake ventilatory response to chemosensory challenge, independent of the specific patient PHOX2B genotype. Graded dysfunction in cardiovascular regulation was found to associate with genotype, suggesting differential effects on different autonomic subsystems. In addition, differences between cases and controls in the cerebrovascular response to chemosensory challenge may indicate alterations in cerebral autoregulation. Thus residual cardiorespiratory responses suggest partial preservation of central nervous system networks that could provide a fulcrum for potential pharmacological interventions.
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Affiliation(s)
- Michael S Carroll
- Center for Autonomic Medicine in Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
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Neary MT, Breckenridge RA. Hypoxia at the heart of sudden infant death syndrome? Pediatr Res 2013; 74:375-9. [PMID: 23863852 PMCID: PMC3977030 DOI: 10.1038/pr.2013.122] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 03/13/2013] [Indexed: 11/09/2022]
Abstract
Sudden infant death syndrome (SIDS) is a significant clinical problem without an accepted pathological mechanism, but with multiple conflicting models. Mutations in a growing number of genes have been found postmortem in SIDS cases, notably genes encoding ion channels. This can only account for a minority of cases, however. Our recent work on a novel mouse model of SIDS suggests a potentially more widespread role for cardiac arrhythmia in SIDS without needing to invoke the inheritance of abnormal ion-channel genes. We propose a model for SIDS pathogenesis whereby postnatal hypoxia leads to delayed maturation of the cardiac conduction system and an increased risk of cardiac arrhythmia. Our model may integrate several epidemiological findings related to risks factors for SIDS, and agrees with previous work suggesting a common final pathological pathway in SIDS.
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Affiliation(s)
- Marianne T. Neary
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Ross A. Breckenridge
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
,Division of Medicine, University College London, United Kingdom
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Guyenet PG, Abbott SBG. Chemoreception and asphyxia-induced arousal. Respir Physiol Neurobiol 2013; 188:333-43. [PMID: 23608705 PMCID: PMC3749262 DOI: 10.1016/j.resp.2013.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/02/2013] [Accepted: 04/06/2013] [Indexed: 02/07/2023]
Abstract
Arousal protects against the adverse and potentially fatal effects of asphyxia during sleep. Asphyxia stimulates the carotid bodies and central chemoreceptors but the sequence of events leading to arousal is uncertain. In this review, the theoretical mechanisms leading to arousal from sleep are briefly summarized and the issue of whether central respiratory chemoreceptors (CRCs) or other types of CO2-responsive CNS neurons contribute to asphyxia-induced arousal is discussed. We focus on the role of the retrotrapezoid nucleus, the raphe and the locus coeruleus and emphasize the anatomical and neurophysiological evidence which suggests that these putative central chemoreceptors could contribute to arousal independently of their effects on breathing. Finally, we describe recent attempts to test the contribution of specific brainstem pathways to asphyxia-induced arousal using optogenetic and other tools and the possible contribution of a group of hypoxia-sensitive brainstem neurons (the C1 cells) to breathing and arousal.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, United States.
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Ramanantsoa N, Gallego J. Congenital central hypoventilation syndrome. Respir Physiol Neurobiol 2013; 189:272-9. [PMID: 23692929 DOI: 10.1016/j.resp.2013.05.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/03/2013] [Accepted: 05/14/2013] [Indexed: 10/26/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) is characterized by hypoventilation during sleep and impaired ventilatory responses to hypercapnia and hypoxemia. Most cases are sporadic and caused by de novo PHOX2B gene mutations, which are usually polyalanine repeat expansions. Physiological and neuroanatomical studies of genetically engineered mice and analyses of cellular responses to mutated Phox2b have shed light on the pathophysiological mechanisms of CCHS. Findings in Phox2b(27Ala/+) knock-in mice consisted of unstable breathing with apneas, absence of the ventilatory response to hypercapnia, death within a few hours after birth, and absence of the retrotrapezoid nucleus (RTN). Conditional mouse mutants in which Phox2b(27Ala) was targeted to the RTN also lacked the ventilatory response to hypercapnia at birth but survived to adulthood and developed a partial hypercapnia response. The therapeutic effects of desogestrel are being evaluated in clinical trials, and recent analyses of cellular responses to polyAla Phox2b aggregates have suggested new pharmacological approaches designed to counteract the toxic effects of mutated Phox2b.
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Affiliation(s)
- N Ramanantsoa
- INSERM, U676, Hôpital Robert Debré, 75019 Paris, France; Université Paris Diderot, Paris, France
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