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EEF1A2 is a gene whose protein product, eukaryotic translation elongation factor 1 alpha 2 (eEF1A2), plays an important role in neurodevelopment. Reports of individuals with pathogenic variants in EEF1A2 are rare, with less than 40 individuals reported world‐wide, however a common feature is the association of the variant with developmental and epileptic encephalopathy. Thus far, there have been limited reports of other organ systems or body functions affected by variants in this gene. Here, we present a case of a child with EEF1A2‐related disorder who presented at 3 months of age with hypotonia, microcephaly, failure to thrive, and respiratory insufficiency with central apneas requiring respiratory support. Our case highlights the notion that the respiratory system may be highly implicated in EEF1A2‐related disorder, allowing for better phenotypic characterization of the disorder. [ABSTRACT FROM AUTHOR]

Background: Craniosynostosis is a rare congenital disease of the skull. They arise when one or more cranial sutures ossify prematurely. This causes an obstruction to normal brain growth and leads to specific deformations of the skull, which may result in intracranial hypertension and cognitive delay. Materials and methods: We have retrospectively analysed all children treated at the Unit of paediatric neurosurgery of the University Medical Centre Ljubljana between June 2015 and September 2020. The following items have been recorded: affected suture, underlying syndromic condition, hydrocephalus, Chiari malformation, raised intracranial pressure, age at surgery, surgical technique, need for multiple operations and surgical complications. Results: During the study period, 71 children have been treated for craniosynostosis. The median postoperative follow-up was 31 months. There were: 54.9% sagittal, 25.3% metopic, 14.0% unicoronal, 1.4% bicoronal and 1.4% unilateral lambdoid craniosynostosis. Multiple sutures were affected in 2.8% cases. 7.0% of the cases were syndromic. Overall, 74 surgical procedures have been performed: frontoorbital advancement represented 40.5% of them; biparietal remodelling 32.4%: total cranial vault remodelling 22.9%; posterior distraction 2.7%; posterior expansion 1.3%. Median age at surgery was 12.8 months. Conclusions: The treatment of craniosynostosis is surgical and requires a multidisciplinary approach, with expertise in plastic and reconstructive surgery, maxillofacial surgery and neurosurgery. The aim of surgical treatment is to release the constrictive and deformative effect that the synostosis has on skull growth. This requires a remodelling of the neurocranium and, if necessary, of the viscerocranium. Beyond aesthetic purposes, the primary aim of surgical treatment is to permit a normal development of the brain. [ABSTRACT FROM AUTHOR]

Summary: Rett syndrome (RTT) is a neurodevelopmental disorder that is characterized by developmental regression, loss of communicative ability, stereotyped hand wringing, cognitive impairment, and central apneas, among many other symptoms. RTT is caused by loss-of-function mutations in a methyl-reader known as methyl-CpG-binding protein 2 (MeCP2), a protein that links epigenetic changes on DNA to larger chromatin structure. Historically, target identification for RTT has relied heavily on Mecp2 knockout mice; however, we recently adopted the alternative approach of performing transcriptional profiling in autopsy samples from RTT patients. Through this mechanism, we identified muscarinic acetylcholine receptors (mAChRs) as potential therapeutic targets. Here, we characterized a cohort of 40 temporal cortex samples from individuals with RTT and quantified significantly decreased levels of the M1, M2, M3, and M5 mAChRs subtypes relative to neurotypical controls. Of these four subtypes, M1 expression demonstrated a linear relationship with MeCP2 expression, such that M1 levels were only diminished in contexts where MeCP2 was also significantly decreased. Further, we show that M1 potentiation with the positive allosteric modulator (PAM) VU0453595 (VU595) rescued social preference, spatial memory, and associative memory deficits, as well as decreased apneas in Mecp2+/- mice. VU595's efficacy on apneas in Mecp2+/- mice was mediated by the facilitation of the transition from inspiration to expiration. Molecular analysis correlated rescue with normalized global gene expression patterns in the brainstem and hippocampus, as well as increased Gsk3β inhibition and NMDA receptor trafficking. Together, these data suggest that M1 PAMs could represent a new class of RTT therapeutics. [ABSTRACT FROM AUTHOR]

Objectives: Some patients with obstructive sleep apnea (OSA) do not respond to Continuous Positive Airway Pressure (CPAP) and for these patients, Bi-level PAP is the next level modality. This study by a theory driven hierarchical approach, tries to identify the predictors for CPAP failure among OSA patients. Methodology: The potential predictors for the model were identified from a theoretical framework rooted in clinical examination, laboratory parameters, and polysomnographic variables pertaining to OSA patients. All patients of OSA who underwent manual titration with CPAP or Bi-level PAP (in case of CPAP Failure) between June 2015 and October 2017 were included in model building. This study compared five competitive models blocks deliberated by increasing order of diagnostic complexity and availability of resources. The fitting of the model was determined by both internal and external validation. Results: Among the five competitive models, the selected model has the significant deviance reduction (−2LL = 121.99, X2 = 25.55, P < 0.0001) from the baseline model (−2LL = 217.356). This logistic regression model consists of the following binary predictors – Age >60 years (odds ratio [OR] = 3.23 [1.27–8.23]), body mass index >35 Kg/m2 (OR = 4.25 [1.78–10.13]), forced expiratory volume <60% (OR = 7.33 [2.83–18.72]), apnea-hypopnea index >75 (OR = 4.31 [1.61–11.56]) and T90 > 30% (OR = 6.67 [2.57–17.36]). Conclusion: These five factors (acronym as BIPAP) may aid to the clinical decision-making by predicting failure of CPAP and therefore may assist in more vigilant clinical care. [ABSTRACT FROM AUTHOR]

Study objectives: The use of mouse models in sleep apnea study is limited by the belief that central (CSA) but not obstructive sleep apneas (OSA) occur in rodents. We aimed to develop a protocol to investigate the presence of OSAs in wild-type mice and, then, to apply it to a validated model of Down syndrome (Ts65Dn), a human pathology characterized by a high incidence of OSAs. Methods: In a pilot study, nine C57BL/6J wild-type mice were implanted with electrodes for electroencephalography (EEG), neck electromyography (nEMG), and diaphragmatic activity (DIA), and then placed in a whole-body-plethysmographic (WBP) chamber for 8 h during the rest (light) phase to simultaneously record sleep and breathing activity. CSA and OSA were discriminated on the basis of WBP and DIA signals recorded simultaneously. The same protocol was then applied to 12 Ts65Dn mice and 14 euploid controls. Results: OSAs represented about half of the apneic events recorded during rapid-eye-movement-sleep (REMS) in each experimental group, while the majority of CSAs were found during non-rapid eye movement sleep. Compared with euploid controls, Ts65Dn mice had a similar total occurrence rate of apneic events during sleep, but a significantly higher occurrence rate of OSAs during REMS, and a significantly lower occurrence rate of CSAs during NREMS. Conclusions: Mice physiologically exhibit both CSAs and OSAs. The latter appear almost exclusively during REMS, and are highly prevalent in Ts65Dn. Mice may, thus, represent a useful model to accelerate the understanding of the pathophysiology and genetics of sleep-disordered breathing and to help the development of new therapies.

Background: Craniosynostosis is a rare congenital disease of the skull. They arise when one or more cranial sutures ossify prematurely. This causes an obstruction to normal brain growth and leads to specific deformations of the skull, which may result in intracranial hypertension and cognitive delay. Materials and methods: We have retrospectively analysed all children treated at the Unit of paediatric neurosurgery of the University Medical Centre Ljubljana between June 2015 and September 2020. The following items have been recorded: affected suture, underlying syndromic condition, hydrocephalus, Chiari malformation, raised intracranial pressure, age at surgery, surgical technique, need for multiple operations and surgical complications. Results: During the study period, 71 children have been treated for craniosynostosis. The median postoperative follow-up was 31 months. There were: 54.9% sagittal, 25.3% metopic, 14.0% unicoronal, 1.4% bicoronal and 1.4% unilateral lambdoid craniosynostosis. Multiple sutures were affected in 2.8% cases. 7.0% of the cases were syndromic. Overall, 74 surgical procedures have been performed: frontoorbital advancement represented 40.5% of them; biparietal remodelling 32.4%: total cranial vault remodelling 22.9%; posterior distraction 2.7%; posterior expansion 1.3%. Median age at surgery was 12.8 months. Conclusions: The treatment of craniosynostosis is surgical and requires a multidisciplinary approach, with expertise in plastic and reconstructive surgery, maxillofacial surgery and neurosurgery. The aim of surgical treatment is to release the constrictive and deformative effect that the synostosis has on skull growth. This requires a remodelling of the neurocranium and, if necessary, of the viscerocranium. Beyond aesthetic purposes, the primary aim of surgical treatment is to permit a normal development of the brain.

Background and Objective Obstructive sleep apnea syndrome (OSAS) is considered to be closely related to systemic inflammation. Resistin levels have been demonstrated to be a measure of systemic inflammation. For children, salivary resistin (SR) sampling is an easy and pain-free method for sample collection and is optimal for multiple sampling. Therefore, we aimed to evaluate correlations among SR levels, objective polysomnography (PSG) parameters, and subjective sleep symptoms. Methods Fifty-six children who attended our clinic over 1 year were enrolled prospectively; these children underwent clinical evaluation, questionnaire studies, and PSG. SR was measured at 2 points: at night before PSG and in the early morning after PSG. Results The subjects (n = 56) were divided into the control [n = 23, apnea hypopnea index (AHI) < 1] and OSAS (n = 33, AHI ≥ 1) groups. SR levels after PSG in the OSAS and control groups were similarly higher than that before PSG. There was no significant difference in SR levels between the two groups and among the control and OSAS subgroups. SR levels in the OSAS subgroups were not related to AHI, tonsil size, AN (adenoid-nasopharyngeal) ratio, questionnaire results, lowest oxygen saturation, and oxygen desaturation index (ODI). Conclusions SR levels had no significant correlation with AHI, scores of the Korean version of modified pediatric Epworth Sleepiness Scale, the lowest oxygen saturation, and ODI; SR levels exhibited diurnal variations regardless of the presence of OSAS. However, there is no consensus regarding the relationship between resistin levels and OSAS. Further studies should be pursued in the future.

Pediatric obstructive sleep apnea (OSA), a relatively common sleep-related breathing disorder affecting ∼1-5% of children, is often caused by anatomical obstruction and/or collapse of the nasal and/or pharyngeal airways. The resulting sleep disruption and intermittent hypoxia lead to various systemic morbidities. Predicting the development of OSA from craniofacial features alone is currently not possible, and controversy remains as to whether upper-airway obstruction facilitates reduced midfacial growth or vice versa. Currently, there is no rodent model that recapitulates both the development of craniofacial abnormalities and upper-airway obstruction to address these questions. Here, we describe that mice with a neural crest-specific deletion of Bmp7 (Bmp7ncko) present with a shorter, more acute-angled cranial base, midfacial hypoplasia, nasal septum deviation, turbinate swelling and branching defects, and nasal airway obstruction. Interestingly, several of these craniofacial features develop after birth during periods of rapid midfacial growth and precede the development of an upper-airway obstruction. We identified that, in this rodent model, no single feature appeared to predict upper-airway obstruction, but the sum of those features resulted in reduced breathing frequency, apneas and overall reduced oxygen consumption. Metabolomics analysis of serum from peripheral blood identified increased levels of hydroxyproline, a metabolite upregulated under hypoxic conditions. As this model recapitulates many features observed in OSA, it offers unique opportunities for studying how upper-airway obstruction affects breathing physiology and leads to systemic morbidities. This article has an associated First Person interview with the first author of the paper.

Fetal ethanol exposure represents a risk factor for sudden infant death syndrome, and the respiratory effects of fetal ethanol exposure promote hypoxic ischemic consequences. This study analyzes central ethanol's effects upon breathing plasticity during an ontogenetic stage equivalent to the human third gestational trimester. Ethanol's unconditioned breathing effects and their intervention in learning processes were examined. Since central ethanol is primarily metabolized via the catalase system, we also examined the effects of early history with the drug upon this system. During postnatal days 3, 5, and 7 (PDs 3-7), pups were intracisternally administered with vehicle or ethanol (300 mg%). They were tested in a plethysmograph scented or not scented with ethanol odor. The state of intoxication attenuated the onset of apneas, a phenomenon that is suggestive of ethanol's anxiolytic effects given the state of arousal caused by the novel environment and the stress of ethanol administration. At PD9, pups were evaluated when sober under sequential air conditions (initial-normoxia, hypoxia, and recovery-normoxia), with or without the presence of ethanol odor. Initial apneic episodes increased when ethanol intoxication was previously associated with the odor. Pups then ingested ethanol, and brain catalase activity was determined. Pre-exposure to ethanol intoxication paired with the odor of the drug resulted in heightened enzymatic activity. Central ethanol exposure appears to exert antianxiety effects that attenuate apneic disruptions. However, during withdrawal, the cues associated with such effects elicit an opposite reaction. The activity of the catalase system was also dependent upon learning processes that involved the association of environmental stimuli and ethanol intoxication. [ABSTRACT FROM AUTHOR]

Opioids are an effective treatment for patients with intractable pain. Long-term administration of opioids for pain relief is being delivered by an increasing number of medical providers in the United States including primary care physicians and nonspecialists. One common complication of chronic opioid use is sleep-disordered breathing which can result in various morbidities as well as an increase in all-cause mortality. It is important for providers to understand the relationship between opioids and sleep-disordered breathing as well as methods to improve diagnosis and strategies for treatment. This review aims to update clinicians on the mechanism, diagnosis, and treatment of opioid-related sleep-disordered breathing in order to improve the quality of care for patients with chronic pain. [ABSTRACT FROM AUTHOR]

In rats, high ethanol doses during early postnatal life exert deleterious effects upon brain development that impact diverse social and cognitive abilities. This stage in development partially overlaps with the third human gestational trimester, commonly referred to as the brain growth spurt period. At this stage in development, human fetuses and rat neonates (postnatal days [PD] 3-9) exhibit relatively high respiratory rates that are affected by subteratogenic ethanol doses. Recent studies suggest conditioned breathing responses in the developing organism, given that there are explicit associations between exteroceptive stimuli and the state of ethanol intoxication. Furthermore, studies performed with near-term rat fetuses suggest heightened sensitivity to ethanol's motivational effects. The present study was meant to analyze the unconditioned effects of ethanol intoxication and the possible co-occurrence of learning mechanisms that can impact respiratory plasticity, and to analyze the preference for cues that signal the state of intoxication as well as the effects of the drug, related with motor stimulation. Neonatal rats were subjected to differential experiences with salient tactile cues explicitly paired or not paired with the effects of vehicle or ethanol (2.0 g/kg). A tactile discrimination procedure applied during PDs 3, 5, 7, and 9 allowed the identification of the emergence of ethanol-derived non-associative and associative learning processes that affect breathing plasticity, particularly when considering apneic disruptions. Ethanol was found to partially inhibit the disruptions that appeared to be intimately related with stressful circumstances defined by the experimental procedure. Tactile cues paired with the drug's effects were also observed to exert an inhibitory effect upon these breathing disruptions. The level of contingency between a given tactile cue and ethanol intoxication also resulted in significant changes in the probability of seeking this cue in a tactile preference test. In addition, the state of intoxication exerted motor-stimulating effects. When contrasting the data obtained via the analysis of the different dependent variables, it appears that most ethanol-derived changes are modulated by positive and/or negative (anti-anxiety) reinforcing effects of the drug. As a whole, the study indicates co-existence of ethanol-related functional changes in the developing organism that simultaneously affect respiratory plasticity and preference patterns elicited by stimuli that signal ethanol's motivational effects. These results emphasize the need to consider significant alterations due to minimal ethanol experiences that argue against "safe" levels of exposure in a critical stage in brain development. [ABSTRACT FROM AUTHOR]

Purpose: The characterization of apneas during polysomnography (PSG) as obstructive or central is a key element of a sleep study. Pulse transit time (PTT) has demonstrated its potential as a noninvasive surrogate marker for inspiratory efforts. The aim of the study was to assess the ability of PTT to classify apneas as central or obstructive, as compared to respiratory inductance plethysmography (RIP) in children.Methods: Overnight PSG with simultaneous PTT recording was performed on 11 consecutive children (mean age 8.9 years, range 1-18.2 years). The same observer scored the apneas using two blinded configurations: (1) the RIP scoring used the nasal pressure, thermistors, thoracic and abdominal movements, and pulse oximetry signals: (2) the PTT scoring used PTT in combination with all the other signals without the thoracic and abdominal movements.Results: One hundred fourteen apneas out of a total of 520 respiratory events were analyzed. With RIP, 58 (51%) apneas were scored as obstructive and 56 (49%) as central. Using PTT, 77 (68%) of the apneas were scored as obstructive and 37 (32%) as central. When using PTT, 30 apneas scored as central by RIP were scored as obstructive. PTT was highly sensitive (81%) but poorly specific (46%) in scoring 58 apneas as obstructive. PTT was less sensitive (46%) but highly specific (81%) to score 56 apneas as central.Conclusion: PTT may be used as an additional tool to RIP to improve the scoring of apneas as obstructive or central in children. The high percentage of artifact is a limitation of PTT. [ABSTRACT FROM AUTHOR]

Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating. We illustrate this procedure with a well-established conductance- based model of the respiratory pattern generator, which allows us to investigate how channel noise affects neural dynamics at the circuit level and, in particular, to understand the relationship between the respiratory pattern and its breath-to-breath variability. We show that as the channel number increases, the duration of inspiration and expiration varies, and so does the coefficient of variation of the breath-to-breath interval, which attains a minimum when the mean duration of expiration slightly exceeds that of inspiration. For small channel numbers, the variability of the expiratory phase dominates over that of the inspiratory phase, and vice versa for large channel numbers. Among the four different cell types in the respiratory pattern generator, pacemaker cells exhibit the highest sensitivity to channel noise. The model shows that suppressing input from the pons leads to longer inspiratory phases, a reduction in breathing frequency, and larger breath-to-breath variability, whereas enhanced input from the raphe nucleus increases breathing frequency without changing its pattern. [ABSTRACT FROM AUTHOR]

Copyright of Monatsschrift Kinderheilkunde is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study tested the hypotheses that 1 ) spleen volume increases during head-out-of-water immersion (HOWI) and returns to pre-HOWI values postdiuresis, and 2 ) the magnitude of apnea-induced spleen contraction increases when preapnea spleen volume is elevated. Spleen volume was measured before and after a set of five apneas in 12 healthy adults (28 ± 5 yr, 3 females) before, during (at 30 and 150 min), and 20 min after temperate temperature (36 ± 1°C) HOWI. At each time point, spleen length, width, and thickness were measured via ultrasound, and spleen volume was calculated using the Pilström equation. Compared with pre-HOWI (276 ± 88 mL), spleen volume was elevated at 30 (353 ± 94 mL, P < 0.01) and 150 (322 ± 87 mL, P < 0.01) min of HOWI but returned to pre-HOWI volume at post-HOWI (281 ± 90 mL, P = 0.58). Spleen volume decreased from pre- to postapnea bouts at each time point ( P < 0.01). The magnitude of reduction in spleen volume from pre- to postapneas was elevated at 30 min of HOWI (-69 ± 24 mL) compared with pre-HOWI (-52 ± 20 mL, P = 0.04) but did not differ from pre-HOWI at 150 min of HOWI (-54 ± 16 mL, P = 0.99) and post-HOWI (-50 ± 18 mL, P = 0.87). Thus, spleen volume is increased throughout 180 min of HOWI, and whereas apnea-induced spleen contraction is augmented after 30 min of HOWI, the magnitude of spleen contraction is unaffected by HOWI thereafter.

Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder and related to multiple conditions that cause mortality in adults. In the present study, reliability of SleepStrip, a disposable screening device for detection of OSAS, is tested. In this prospective, nonrandomized double-blinded single cohort study at an academic health center, the performance of the SleepStrip in detecting respiratory events and establishing an SleepStrip score (Sscore) in domestic use were compared to the apnea-hypopnea index (AHI) obtained by the standard polysomnography (PSG) recordings in the sleep laboratory. Forty-one patients who have the PSG results participated the study and wore the SleepStrips at home. Test efficiency rate was 75 % and there was a positive correlation between PSG-AHI scores and Sscores ( r = 0.71, p < 0.001). However, diagnostic accuracy analysis showed that the correlation between Sscores and PSG-AHI scores were significant only at AHI > 30 levels. The SleepStrip has 100 % specificity and positive predictive values, but it also has low negative predictive and sensitivity values. The SleepStrip is not a reliable screening test in differential diagnosis among simple snorers, mild, moderate and severe OSAS patients. However, high Sscores highly indicate the presence of moderate-severe OSAS. We can safely send these patients to split-night PSG and continuous, automatic, bi-level positive airway pressure (CPAP/BPAP/APAP) titration at the same night. The SleepStrip may increase the effective use of the sleep laboratories. [ABSTRACT FROM AUTHOR]

Copyright of Medicina (Buenos Aires) is the property of Medicina (Buenos Aires) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hypofunction of cholinergic circuits and diminished cholinergic tone have been associated with the neurodevelopmental disorder Rett syndrome (RTT). Specifically, deletion of Mecp2 in cholinergic neurons evokes the same social and cognitive phenotypes in mice seen with global Mecp2 knockout, and decreased choline acetyltransferase activity and vesamicol binding have been reported in RTT autopsy samples. Further, we recently identified significant decreases in muscarinic acetylcholine receptor subtype 4 (M 4 ) expression in both the motor cortex and cerebellum of RTT patient autopsies and established proof of concept that an acute dose of the positive allosteric modulator (PAM) VU0467154 (VU154) rescued phenotypes in Mecp2 +/- mice. Here, we expand the assessment of M 4 PAMs in RTT to address clinically relevant questions of tolerance, scope of benefit, dose response, chronic treatment, and mechanism. We show that VU154 has efficacy on anxiety, social preference, cognitive, and respiratory phenotypes in Mecp2 +/- mice; however, the therapeutic range is narrow, with benefits seen at 3 mg/kg concentrations, but not 1 or 10 mg/kg. Further, sociability was diminished in VU154-treated Mecp2 +/- mice, suggestive of a potential adverse effect. Compound efficacy on social, cognitive, and respiratory phenotypes was conserved with a 44-day treatment paradigm, with the caveat that breath rate was moderately decreased with chronic treatment in Mecp2 +/+ and Mecp2 +/- mice. VU154 effects on respiratory function correlated with an increase in Gsk3β inhibition in the brainstem. These results identify the core symptom domains where efficacy and adverse effects may present with M 4 administration in RTT model mice and advocate for the continued evaluation as potential RTT therapeutics.

Objective: To describe the clinical presentation of 48 cases and the risk factors associated with mortality. Study Design: Transversal, descriptive, between January 2009 and March 2010. Materials y Methods: Two groups were compared for the descriptive analysis: group 1; patients who passed away, group 2, patients who survived. The selected variables were: Age, sex, cough characteristics, vaccination history, leukocytosis, X-ray, antimicrobial treatment and mortality. The statistic significance was evaluated by Student T test, Pearson Χ² test and Fisher's Exact Test. Results of p <.05 were considered significant. Results: Positive samples to patients in 18 cases (38%), positive samples to relatives in 5 cases (10%). Positive samples group 1; 7 cases (100%), positive samples group 2, 11 cases (61%). Apneas: group 1; 7 cases, group 2: 5 cases; 42% when p = 0.001 (significant). Pneumonias: group 1; 7 cases, group 2; 25 cases, when p= 0.0001 (significant). Starting leucocytes (average) group1; 74,457 mm3. Group 2 51,667 mm3, p = 0.0177. Leukocytosis on day 4; group 1 80,014. Group 2 20,428 mm3, when p = 0.0001. Mortality 15%. Conclusions: Presence of apnea, leukocytosis and pneumonia can be considered as a risk factor considering they were significantly higher in G1 in comparison to G2. [ABSTRACT FROM AUTHOR]

Abstract: Sleep disordered breathing with recurrent apneas is one of the most frequently encountered breathing disorder in adult humans and preterm infants. Recurrent apnea patients exhibit several co-morbidities including hypertension and persistent sympathetic activation. Intermittent hypoxia (IH) resulting from apneas appears to be the primary stimulus for evoking autonomic changes. The purpose of this article is to briefly review the effects of IH on chemo- and baro-reflexes and circulating vasoactive hormones and their contribution to sympathetic activation and blood pressures. Sleep apnea patients and IH-treated rodents exhibit exaggerated arterial chemo-reflex. Studies on rodent models demonstrated that IH leads to hyperactive carotid body response to hypoxia. On the other hand, baro-reflex function is attenuated in patients with sleep apnea and in IH-treated rodents. Circulating vasoactive hormone levels are elevated in sleep apnea patients and in rodent models of IH. Thus, persistent sympathetic activation and hypertension associated with sleep apneas seems to be due to a combination of altered chemo- and baro-reflexes resulting in sympathetic activation and action of elevated circulating levels of vasoactive hormones on vasculature. [ABSTRACT FROM AUTHOR]

Abstract: We tested the hypothesis that postnatal exposure to progesterone or estradiol exerts distinct effects on respiratory control, apnea frequency, and on hypoxic ventilatory response (HVR). To this aim, we assessed breathing pattern using whole body plethysmography in normoxia and during a sustained hypoxic exposure (10% O2—30min) in 10-day-old male rats raised by dams implanted with osmotic minipumps delivering either estradiol (E2, 7.0μgday−1), estradiol+progesterone (E2 +P, 7.0+70μgday−1) or vehicle (propylene glycol) at a regular flow rate throughout postnatal days 1–14. Compared to vehicle, E2 and E2 +P pups had a reduced ventilation, metabolic rate and rectal temperature. HVR was specifically increased in E2 +P pups compared to controls and E2 pups. On the contrary, both E2 and E2 +P pups did not reduced metabolism as much as controls during hypoxic exposure, and the decrease in rectal temperature was abolished. Surprisingly, E2 +P pups showed a dramatic elevation of sigh frequency, while progesterone (in E2 +P compared to E2 and Veh pups) reduced apnea frequency. These findings are relevant to better understand the role of placental steroids on respiratory and metabolic control during early development in rats, and could ultimately contribute to a better understanding of specific respiratory control disorders in preterm neonates, which are chronically deprived from placental steroids exposure. [Copyright &y& Elsevier]

The use of mouse models in sleep apnea study is limited by the belief that central (CSA) but not obstructive sleep apneas (OSA) occur in rodents. We aimed to develop a protocol to investigate the presence of OSAs in wild-type mice and, then, to apply it to a validated model of Down syndrome (Ts65Dn), a human pathology characterized by a high incidence of OSAs. In a pilot study, nine C57BL/6J wild-type mice were implanted with electrodes for electroencephalography (EEG), neck electromyography (nEMG), and diaphragmatic activity (DIA), and then placed in a whole-body-plethysmographic (WBP) chamber for 8 h during the rest (light) phase to simultaneously record sleep and breathing activity. CSA and OSA were discriminated on the basis of WBP and DIA signals recorded simultaneously. The same protocol was then applied to 12 Ts65Dn mice and 14 euploid controls. OSAs represented about half of the apneic events recorded during rapid-eye-movement-sleep (REMS) in each experimental group, while the majority of CSAs were found during non-rapid eye movement sleep. Compared with euploid controls, Ts65Dn mice had a similar total occurrence rate of apneic events during sleep, but a significantly higher occurrence rate of OSAs during REMS, and a significantly lower occurrence rate of CSAs during NREMS. Mice physiologically exhibit both CSAs and OSAs. The latter appear almost exclusively during REMS, and are highly prevalent in Ts65Dn. Mice may, thus, represent a useful model to accelerate the understanding of the pathophysiology and genetics of sleep-disordered breathing and to help the development of new therapies. • Mice physiologically exhibit both central sleep apneas and obstructive sleep apneas. • Obstructive sleep apneas appear almost exclusively during rapid-eye-movement-sleep. • Obstructive sleep apneas are prevalent in Ts65Dn, a mouse model of Down syndrome. • Mice models help to understand the pathophysiology of sleep-disordered breathing. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the effect of hypercapnia and hypoxia on apnea and nonnutritive swallowing (NNS) frequency, as well as on the coordination between NNS and phases of the respiratory cycle in newborn lambs, while taking into account the potential effects of states of alertness. Six lambs were chronically instrumented for recording electroencephalogram, eye movements, diaphragm and thyroarytenoid muscle (a glottal adductor) activity, nasal airflow, and electro-cardiogram. Polysomnographic recordings were performed in nonsedated lambs exposed to air (control), 10% 02, and 5% CO2 in a random order at 3, 4, and 5 days of age. Although hypercapnia decreased apnea frequency in wakefulness and active sleep (P = 0.002 vs. air and hypoxia), hypoxia had no significant effect on apnea. In addition, although hypercapnia increased NNS frequency during wakefulness and quiet sleep (P < 0.005 vs. air and hypoxia), hypoxia tended to decrease NNS frequency. Finally, only hypercapnia altered NNS-breathing coordination by increasing NNS at the transition from inspiration to expiration (ie-type NNS; P < 0.001 vs. air and hypoxia). In conclusion, whereas hypercapnia increases overall NNS frequency by specifically increasing ie-type NNS, hypoxia has the inverse tendency. Results were identical in all three states of alertness. [ABSTRACT FROM AUTHOR]

Rett syndrome (RS) is a severe X-linked neurological disorder in which most patients have mutations in the methyl-CpG binding protein2 ( MECP2) gene. No effective treatment exists. We previously showed that the Mecp2-deficient mice, a mouse model of RS, have highly variable respiratory rhythm and frequent apneas due to reduced norepinephrine (NE) content, and a drastic decrease of tyrosine hydroxylase (TH)-expressing neurons in the medulla. We showed here that treating these mice with desipramine (DMI), which specifically inhibits NE reuptake, significantly improved their respiratory rhythm during several weeks. In addition, the treatment significantly extended their lifespan. At the cellular level, we showed that the reduced number of TH-expressing neurons before treatment in the mutant animals was not due to apoptosis. Conversely, we found that DMI treatment increased the number of TH-expressing neurons in the mutant brainstem to reach wild-type levels. We showed that this increase was not due to cellular proliferation. We propose that the Mecp2-deficient TH-expressing neurons lose their ability to synthesize TH at some point during their postnatal development. Our results suggest that a pharmacological stimulation of the noradrenergic system could be a promising approach for the treatment of the respiratory dysfunction which causes a significant proportion of death in RS patients. [ABSTRACT FROM AUTHOR]

The first polysomnographic recordings with concomitant monitoring of cardiocirculatory parameters demonstrated that obstructive apneas arising during sleep are accompanied by a marked increase in pulmonary and systemic arterial pressure and severe alveolar hypoventilation. Apneas also may give rise to cardiac arrhythmias, namely potentially life-threatening bradyarrhythmias. The long-term repercussions of these nocturnal cardiocirculatory changes on subsequent cardiovascular diseases and the patient's life expectancy are more controversial. There is little doubt that patients with obstructive sleep apnea syndrome (OSAS) have systemic arterial hypertension, ischemic heart disease, transient ischemic attacks, or stroke more often than control populations and have a shorter life expectancy. However, these clinical manifestations may be at least partly due to myriad other risk factors almost always present in OSAS patients (in particular obesity, diabetes, alcoholism, and cigarette smoking). Few multivariate epidemiological surveys have addressed all these confounding factors. The effectiveness of continuous positive airway pressure treatment in reducing the incidence of cardiovascular comorbidity in OSAS patients is not disputed, even though controlled epidemiological surveys on large populations are scant. This overview of cardiovascular disorders and OSAS examines the latest literature findings aimed at establishing the true impact of nocturnal apneas on cardiocirculatory disease (systemic arterial hypertension, ischemic heart disease, stroke, pulmonary hypertension and right heart failure and mortality). [ABSTRACT FROM AUTHOR]

Carotid bodies are functionally immature at birth and exhibit poor sensitivity to hypoxia. Previous studies have shown that continuous hypoxia at birth impairs hypoxic sensing at the carotid body. Intermittent hypoxia (IH) is more frequently experienced in neonatal life. Previous studies on adult animals have shown that IH facilitates hypoxic sensing at the carotid bodies. On the basis of these studies, in the present study we tested the hypothesis that neonatal IH facilitates hypoxic sensing of the carotid body and augments ventilatory response to hypoxia. Experiments were performed on 2-day-old rat pups that were exposed to 16 h of IH soon after the birth. The IH paradigm consisted of 15 s of 5% O2 (nadir) followed by 5 min of 21% O2 (9 episodes/h). In one group of experiments (IH and control, n = 6 pups each), sensory activity was recorded from ex vivo carotid bodies, and in the other (IH and control, n = 7 pups each) ventilation was monitored in unanesthetized pups by plethysmography. In control pups, sensory response of the carotid body was weak and was slow in onset (∼100 s). In contrast, carotid body sensory response to hypoxia was greater and the time course of the response was faster (-30 s) in IH compared with control pups. The magnitude of the hypoxic ventilatory response was greater in IH compared with control pups, whereas changes in O2 consumption and CO2 production during hypoxia were comparable between both groups. The magnitude of ventilatory stimulation by hyperoxic hypercapnia (7% CO2-balance O2), however, was the same between both groups of pups. These results demonstrate that neonatal IH facilitates carotid body sensory response to hypoxia and augments hypoxic ventilatory chemoreflex. [ABSTRACT FROM AUTHOR]

Analysis of time-series multichannel physiological data were performed using wavelets. Wavelet provides a time-scale description and lead us to decompose any signal into frequency bands. A better precision in the frequency domain is often necessary to detect stationary phenomena or characterize time–frequency structures. A natural idea is to combine wavelet analysis with local Fourier analysis using an appropriate strategy: the wave packets. In this paper, we apply trigonometric wave packets to determine the time lag between the start of the apneas in the breathing and the consistent disorder in the cardiac rhythm. We show that breathing dynamic drives the evolution of the cardiac rhythm. [Copyright &y& Elsevier]

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Objective: To investigate the features of cardiorespiratory events in infants born preterm during the transitional period, and to evaluate whether different neonatal characteristics may correlate with event type, duration, and severity.Study Design: Infants with gestational age (GA) <32 weeks and/or birth weight <1500 g were enrolled in this observational prospective study. Heart rate (HR) and peripheral oxygen saturation (SpO2) were recorded continuously over the first 72 hours. Cardiorespiratory events of ≥10 seconds were clustered into isolated desaturation (SpO2 <85%), isolated bradycardia (HR <100 bpm or <70% of baseline), or combined desaturation/bradycardia and classified as mild, moderate, or severe. The daily incidences of isolated desaturation, isolated bradycardia, and combined desaturation and bradycardia were analyzed. The effects of relevant clinical variables on cardiorespiratory event type and severity were assessed using generalized estimating equations.Results: Among the 1050 events analyzed, isolated desaturations were the most frequent (n = 625) and isolated bradycardias the least common (n = 171). The number of cardiorespiratory events increased significantly from day 1 to day 2 (P = .028). One in 5 events had severe characteristics; event severity was highest for combined desaturation and bradycardia (P < .001). Compared with other event types, the incidence of combined desaturation and bradycardia was inversely correlated with GA (P = .029) and was higher with the use of continuous positive airway pressure (P = .002). The presence of a hemodynamically significant patent ductus arteriosus was associated with the occurrence of isolated desaturations (P = .001) and with a longer duration of cardiorespiratory events (P = .003).Conclusions: Cardiorespiratory events during transition exhibit distinct types, duration, and severity. Neonatal characteristics are associated with the clinical features of these events, indicating that a tailored clinical approach may reduce the hypoxic burden in preterm infants aged 0-72 hours. [ABSTRACT FROM AUTHOR]

Pediatric obstructive sleep apnea (OSA), a relatively common sleep-related breathing disorder (SRBD) affecting approximately 1-5% of children, is often caused by anatomical obstruction and/or collapse of the nasal and/or pharyngeal airways. The resulting sleep disruption and intermittent hypoxia lead to various systemic morbidities. Predicting the development of OSA from craniofacial features alone is currently not possible and a controversy remains if upper airway obstruction facilitates reduced midfacial growth or vice-versa. Currently, there is no rodent model that recapitulates both the development of craniofacial abnormalities and upper airway obstruction to address these questions. Here, we describe that mice with a neural crest-specific deletion of Bmp7 (Bmp7 ncko ) present with shorter, more acute angled cranial base, midfacial hypoplasia, nasal septum deviation, turbinate swelling and branching defects, and nasal airway obstruction. Interestingly, several of these craniofacial features develop after birth during periods of rapid midfacial growth and precede the development of an upper airway obstruction. We identified that in this rodent model, no single feature appeared to predict upper airway obstruction, but the sum of those features resulted in a reduced breathing frequency, apneas and overall reduced oxygen consumption. Metabolomics analysis of serum from peripheral blood identified increased levels of hydroxyproline, a metabolite upregulated under hypoxic conditions. As this model recapitulates many features observed in OSA, it offers unique opportunities for studying how upper airway obstruction affects breathing physiology and leads to systemic morbidities., (© 2021. Published by The Company of Biologists Ltd.)

Multiple sclerosis (MS) is a mainly demyelinating, autoimmune, and disabling neurological disease. In addition to well-known clinically evident symptoms such as coordination or motor problems, increasing attention has been posed to a constellation of less evident symptoms significantly contributing to the clinical impact of MS. Among others, sleep symptoms have been only recently explored. This systematic review summarizes objective sleep findings detected by using polysomnography and their relationship with clinical variables in MS patients. While it is well known that sleep disorders are frequent in MS, objective clinical data are still scarce. Literature based on subjective reports indicate sleep disorders as highly frequent in MS patients; however, objective data are still scarce. New large case-control instrumental investigations are warranted to establish the real objective entity and impact of sleep comorbidities., (© Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.)

Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating. We illustrate this procedure with a well-established conductance-based model of the respiratory pattern generator, which allows us to investigate how channel noise affects neural dynamics at the circuit level and, in particular, to understand the relationship between the respiratory pattern and its breath-to-breath variability. We show that as the channel number increases, the duration of inspiration and expiration varies, and so does the coefficient of variation of the breath-to-breath interval, which attains a minimum when the mean duration of expiration slightly exceeds that of inspiration. For small channel numbers, the variability of the expiratory phase dominates over that of the inspiratory phase, and vice versa for large channel numbers. Among the four different cell types in the respiratory pattern generator, pacemaker cells exhibit the highest sensitivity to channel noise. The model shows that suppressing input from the pons leads to longer inspiratory phases, a reduction in breathing frequency, and larger breath-to-breath variability, whereas enhanced input from the raphe nucleus increases breathing frequency without changing its pattern., New & Noteworthy: A major source of noise in neuronal circuits is the "flickering" of ion currents passing through the neurons' membranes (channel noise), which cannot be suppressed experimentally. Computational simulations are therefore the best way to investigate the effects of this physiological noise by manipulating its level at will. We investigate the role of noise in the respiratory pattern generator and show that endogenous, breath-to-breath variability is tightly linked to the respiratory pattern., (Copyright © 2017 the American Physiological Society.)