Pathological data on apoptosis in the brainstem and physiological data on sleep apnea in SIDS victims.
ABSTRACT The sudden infant death syndrome (SIDS) is still the main cause of postneonatal infant death and its cause is still unknown. A chronic hypoxic situation has been shown to exist in the brains of SIDS victims and apoptosis has been demonstrated in hypoxic situations. In this study, the correlation between apoptotic neurons or glias and sleep apnea in SIDS was investigated in the brainstem of SIDS victims.
In a cohort of 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age. They included 26 cases of SIDS. The frequency and duration of sleep apnea were analyzed. The brainstem material was collected and terminal-deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method was carried out. The density of TUNEL-positive neurons or glias was measured quantitatively. Correlation analyses were carried out between the apoptosis-associated pathological data and the physiological data of sleep apnea.
No significant negative or positive correlation between the density of TUNEL-positive neurons or glias and the characteristics of sleep apnea was observed in SIDS victims. No statistically significant differences associated with apoptotic neurons and glias were observed between SIDS and non-SIDS.
The pathological findings of apoptosis were not in agreement with the hypothesis refer to apnea and arousal phenomenon in pathophysiology of SIDS.
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ABSTRACT: Maternal cigarette smoking is a major risk factor for sudden infant death syndrome (SIDS); however, the mechanism underlying this association is currently unknown. Prenatal nicotine exposure is accompanied by a decrease in the magnitude of hypoxic ventilatory depression, the component of hypoxic ventilatory response that activates the PDGF-beta receptor (PDGFR) and its downstream anti-apoptotic cascade in the caudal brainstem (CB) of developing rats. In this study, we evaluated the effect of prenatal nicotine exposure on PDGFR activation and the subsequent activation of downstream anti-apoptotic processes through the Akt/BAD pathway. The 5-day timed-pregnant Sprague-Dawley rats underwent surgical implantation of an osmotic pump containing either normal saline (control) or a solution of nicotine tartrate. The CB was harvested from 5-day-old rat pups (n=8-10 for each time point) in each group after exposure to normoxia or hypoxic challenges with 10% O(2) for 5, 15, 30, 60 or 120 min. Immunoprecipitation and immunoblots of CB lysates revealed phosphorylation of PDGFR, Akt and BAD-136 during hypoxia in control pups. Prenatal nicotine exposure was associated with attenuation of these responses at all time points. Analysis of an early apoptotic marker in the CB revealed that activation of cleaved caspase-3 occurred only at 120 min of hypoxic exposure in the control. Prenatal nicotine exposure accelerated this response, causing early activation at 30 and 60 min. We conclude that prenatal nicotine exposure attenuates the phosphorylation of PDGFR, Akt and Bad-136 during hypoxia in the CB of developing rats. This modulation of anti-apoptotic cascades accelerates activation of the early apoptotic marker. We speculate that prenatal nicotine exposure affects apoptosis in the CB of developing animals and may increase the vulnerability of neural cells in the respiratory control area, a process that may underlie the association between maternal smoking and SIDS.Neuroscience Letters 06/2010; 478(1):46-50. · 2.03 Impact Factor
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ABSTRACT: Sudden infant death syndrome (SIDS) is a leading cause of post-neonatal infant death in the developed world. The cause of SIDS is unknown but several hypotheses have been proposed, including the 'triple risk hypothesis', which predicts that fetal development of infants who subsequently succumb to SIDS is abnormal, leaving them unable to respond appropriately to stressors. Consistent with this hypothesis, a large number of studies have reported changes in the brain in SIDS. However, on nearly every subject, the reported findings vary widely between studies. Inconsistencies in the definitions of SIDS used and in control group selection are likely to underlie much of this variability. Therefore, in our analysis, we have included only those studies that met simple criteria for both the definition of SIDS and the control group. Of the 153 studies retrieved by our review of the literature, 42 (27%) met these criteria. Foremost amongst the findings reported by these studies are abnormalities of the brain stem, in particular brain stem gliosis and defects of neurotransmission in the medulla. However, these studies have not identified what could be considered in diagnostic terms a causative structural or biochemical abnormality for use in routine clinical practice. An assessment of changes in the architecture and composition of brain regions and changes in neurotransmission in multiple systems in a single, large cohort of well- and consistently-characterized infants dying suddenly of a range of causes is needed before the interrelation of these different features can be appreciated.Neuropathology and Applied Neurobiology 10/2013; · 4.84 Impact Factor