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Fetal nicotine exposure blunts hypoxia-induced catecholamine secretion from neonatal adrenomedullary chromaffin cells (AMCs), providing a link between maternal smoking, abnormal arousal responses, and risk of sudden infant death syndrome. Here, we show that the mechanism is attributable to upregulation of KATP channels via stimulation of {alpha}7 nicotinic ACh receptors (AChRs). These KATP channels open during hypoxia, thereby suppressing membrane excitability. After in utero exposure to chronic nicotine, neonatal AMCs show a blunted hypoxic sensitivity as determined by inhibition of outward K+ current, membrane depolarization, rise in cytosolic Ca2+, and catecholamine secretion. However, hypoxic sensitivity could be unmasked in nicotine-exposed AMCs when glibenclamide, a blocker of KATP channels, was present. Both KATP current density and KATP channel subunit (Kir 6.2) expression were significantly enhanced in nicotine-exposed cells relative to controls.
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A new study has identified a specific class of pharmaceutical drugs that could be effective in treating babies vulnerable to Sudden Infant Death Syndrome (SIDS), because their mothers smoked during pregnancy.
According to researchers at McMaster University, exposure of the fetus to nicotine results in the inability to respond to decreases in oxygen - known as hypoxia - which may result in a higher incidence of SIDS. In the same study on rats, they found that the diabetic medication 'glibenclamide' can reverse the effects of nicotine exposure, increasing the newborn's ability to respond to hypoxia and likely reducing the incidence of SIDS.
The findings are published in the Journal of Neuroscience.
"During birth the baby rapidly changes its physiology and anatomy so that it can breathe on its own," explains Josef Buttigieg, lead author who conducted his research as a PhD graduate student in the department of Biology. "The stress of being born induces the release of the hormones adrenaline and noradrenaline - collectively called catecholamines - from the adrenal glands. During birth, these hormones in turn signal the baby's lungs to become ready for air breathing."
A study in the April 1 issue of the journal SLEEP shows that maternal smoking is associated with an impaired infant arousal process that may increase the risk for sudden infant death syndrome (SIDS). The authors suggest that maternal smoking has replaced stomach sleeping as the greatest modifiable risk factor for SIDS.
Results show that the progression from sub-cortical activation to cortical arousal was depressed in smoke-exposed infants, who had lower proportions of full cortical arousals from sleep and higher proportions of sub-cortical activations than infants born to non-smoking mothers. The study also indicates that there is a dose-dependent relationship between cortical activation proportions and levels of infant urinary cotinine, a nicotine metabolite. Cortical arousals were lowest in babies with higher levels of smoke exposure.
According to senior investigator Rosemary Horne, PhD, scientific director of the Ritchie Centre for Baby Health Research at Monash University in Melbourne, Australia, decreased cortical arousals from sleep have been observed in victims of SIDS prior to death.
Monash University researchers have shown that babies born to a mother who smokes are more likely to be slower to wake or respond to stimulation - and this may explain their increased risk of Sudden Infant Death Syndrome (SIDS).
Scientific director of the Ritchie Centre for Baby Health Research Associate Professor Rosemary Horne and PhD student Heidi Richardson compared babies of mothers who smoked both during the pregnancy and after the baby was born, with babies who lived in a smoke-free environment.
Professor Horne said the study suggested that maternal smoking can impair a baby's ability to respond to external stimuli, which may explain their increased risk of SIDS.
"Those babies whose mothers smoked did not have as many arousals overall and the progression of the arousal response through the brain was also impaired. Mothers who smoked while pregnant and continued to smoke afterward significantly increased their baby's chances of succumbing to SIDS," Professor Horne said.
Researchers in Sydney have found the first direct evidence that exposure to cigarette smoke increases the risk of sudden infant death syndrome (SIDS).
The research, conducted by the University of Sydney's Bosch Institute, found exposure to second-hand smoke caused changes to babies' brain cells.
Researchers led by Rita Machaalani were trying to turn parents' tragedy into medical progress, analysing brain tissue from babies who had undergone autopsies at Glebe morgue.
They found 81 per cent of the infants who died of SIDS had been exposed to cigarette smoke, while only 58 per cent of those who died of other causes were exposed to second-hand smoke.
The immunoreactivity of the serotoninergic receptor subtype 1A (5HT1AR) was quantitatively analyzed in the human infant brainstem medulla (caudal and rostral levels). We hypothesized that immunoreactivity of 5HT1AR would be reduced in infants diagnosed with sudden infant death syndrome (SIDS). In particular that those infants with known clinical risk factors (including cigarette smoke exposure, bed sharing and sleep position) would have greater changes than those without clinical risks. Comparing SIDS (n = 67) to infants who died suddenly with another diagnosis (non-SIDS, n = 25), we found decreased 5HT1AR immunoreactivity in the majority of the nuclei studied at the rostral medulla level including dorsal motor nucleus of the vagus (DMNV), nucleus of the solitary tract, vestibular, and inferior olivary nucleus (ION). There was a significant relationship with all risk factors for 5HT1AR, especially for DMNV, suggesting that 5HT1ARs are highly vulnerable to various insults within the SIDS DMNV. This study not only provides further evidence of abnormalities within the brainstem serotoninergic system of SIDS infants, but also shows that these changes may be associated with exposure to clinical risk factors.
Babies born to smoking mums find it harder to rouse from sleep, say Australian researchers who have probed the link between cigarettes and Sudden Infant Death Syndrome (SIDS).
The Melbourne-based study found babies in homes where the mother smoked up to 20 cigarettes daily, during and after the pregnancy, performed poorer on arousal tests.
Associate Professor Rosemary Horne said the research shed new light on why smoking was emerging as a leading SIDS cause.
"With maternal smoking, even though these babies appeared perfectly well and healthy and normal, they did not have the same arousal patterns as those babies whose mums didn't smoke," said Prof Horne, scientific director of the Ritchie Centre for Baby Health Research at Monash University.
"They wake up less, and more of the arousals they do have don't go right up to the cortex, so they don't wake up." , , ,''
Prof Horne's study is published in the journal SLEEP.
Smoking by mothers has replaced infants sleeping on their stomachs as the greatest modifiable risk factor for sudden infant death syndrome, or SIDS, Australian researchers suggest.
They found that when mothers smoke, the sleep arousal process of infants, which awakens them in response to a life-threatening situation, is altered, increasing the risk for SIDS.
The study included 12 healthy, full-term infants born to mothers who smoked an average of 15 cigarettes a day. . . .
"Our study suggests that maternal smoking can impair the arousal pathways of seemingly normal infants, which may explain their increased risk for SIDS," Horne said in a news release from the American Academy of Sleep Medicine.
The study is in the April 1 issue of the journal Sleep.
Infants who slept in a bedroom with a fan ventilating the air had a 72 percent lower risk of Sudden Infant Death Syndrome compared to infants who slept in a bedroom without a fan, according to a new study by the Kaiser Permanente Division of Research. The study appears in the October issue of the Archives of Pediatric & Adolescent Medicine.
This is the first study to examine an association between better air ventilation in infants' bedrooms and reduced SIDS risk. . . .
They explained that fan use is no substitute for practices known to reduce the risk for sudden infant death syndrome, which include: always placing infants to sleep on their backs, putting infants to sleep on firm mattresses and avoiding soft bedding materials like comforters and quilts, providing a separate sleep environment, preventing infants from overheating, and not smoking around infants.
Premature infants whose mothers smoked during pregnancy may be at even higher risk for sudden infant death syndrome (SIDS) than preemies whose mothers did not smoke, according to new research out of the University of Calgary. In the first-ever experimental study to compare the breathing reflexes of preemies of smokers versus non-smokers, researchers found that babies whose mothers had smoked showed a number of signs of impaired respiratory function.
"Smoking during pregnancy is a double-edged sword with respect to SIDS," said Shabih Hasan, M.D., a staff neonatologist and professor in the department of pediatrics at the University of Calgary, and the principal investigator of the new study. "Not only does it raise a mother's likelihood of having a preterm baby, who is already among the most vulnerable to SIDS, but it increases the infant's susceptibility to SIDS even further."
The research will be published in the first issue for September of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
Babies born prematurely to women who smoked during their pregnancy may be at higher risk of sudden infant death syndrome (SIDS) than premature infants born to nonsmoking moms, new research suggests.
The Canadian study is the first to compare the breathing reflexes of "preemies" born to smokers versus nonsmokers. The researchers found that these tiny babies were more likely to have impaired recovery from pauses in breathing if their mother had smoked during her pregnancy.
"Our study shows that preterm infants make incomplete and/or delayed recovery from interruptions in breathing," study author and neonatologist Dr. Shabih Hasan, a professor of pediatrics at the University of Calgary, said in an American Thoracic Society news release. "This has clear implications for their risk of SIDS."
The study, published in the first issue for September of the American Journal of Respiratory and Critical Care Medicine, involved 22 infants born spontaneously between 28 and 32 weeks of gestation
Prenatal cigarette smoke exposure, the main risk factor for sudden infant death syndrome (SIDS), has an adverse effect on spontaneous recovery of breathing pauses and oxygen saturation during hypoxemia in preterm infants, researchers report.
Preterm infants are among the most vulnerable groups for SIDS, but the effects of prenatal cigarette smoke exposure and hypoxemia on their cardio-respiratory control have not been investigated, explain Shabih Hasan and colleagues from the University of Calgary in Alberta, Canada, in the American Journal of Respiratory and Critical Care Medicine.
A THIRD of babies whose parents smoke at home end up in hospital before their first birthday, research shows.
But Australian experts say many parents continue to endanger their children's health by smoking around them, despite overwhelming evidence of the risks.
Doctors have found passive smoking weakens babies' immune systems and puts them at higher risk of potentially lethal infectious diseases.
The study, published on the respected Tobacco Control journal's website, followed 7402 children born in 1997 for eight years