Ethanol´'s sensory attributes trigger respiratory disruptions and appetitive facial responses in human newborns prenatally exposed to maternal binge drinking episodes.

MITRANO, A.S.; D'ALOISIO, G; ANUNZIATA, F; MACCHIONE, AF; MOLINA, JC; FERREYRA, M.E.; AHUMADA, L.A.

PALERMO

Conferencia; 1st International Conference of ?Perinatal Origins of Neuropsychiatric Disorders: from molecular mechanisms to therapeutic perspectives? (POND); 2019

Internationally, fetal alcohol exposure represents one of the main congenital risks concerning the integrity and development of human beings. In 2017 the World Health Organization reported that 11.4% of women in the Americas drink alcohol during pregnancy. A recent study conducted in Argentina indicated that the prevalence of alcohol consumption during pregnancy is equivalent to 75.2%. Following maternal ethanol ingestion fetuses process the drug´s chemosensory cues present in the amniotic fluid. The unborn organism is also capable of associating these cues with physiological effects of the drug. In altricial mammals, ethanol suppresses fetal breathing movements and later neonatal exposure to ethanol odor elicits conditioned breathing depression. In the present study we analyzed if human neonates (postnatal age: 24-48 hrs.) exhibit specific patterns of behavioral and physiological responses to ethanol odor as a function of prenatal alcohol exposure. Mothers were classified as low, moderate or high (social binge drinking) drinkers according to ethanol intake patterns during pregnancy. Eighty neonates were tested in terms of oxygen saturation levels and respiratory and cardiac frequencies when primarily exposed to ethanol or lemon odor. Different clinical assessments indicated that all neonates did not suffer congenital or genetic diseases and that they were completely healthy at birth. No significant differences were observed across maternal groups in terms of neonatal body weights and sizes, head circumferences, Apgar scores, gestational ages, or oxygen saturation scores. When neonates were stimulated with lemon, the physiological and behavioral repertory was similar across maternal groups. Neonatal exposure to ethanol odor significantly affected breathing rates of newborns representative of binge drinking mothers. This group exhibited a significant decrease in breathing rates relative to neonates delivered by low drinkers. These babies also exhibited lower cardiac frequencies independently from the olfactory cue that they were exposed to. Furthermore, this group of neonates showed significantly higher frequency and duration of appetitive facial reactions coupled with lesser aversive facial expressions while being exposed to ethanol odor. No differences were encountered between groups when employing a novel scent (lemon). The results indicate that neonatal breathing alterations are observed as a function of relatively high ethanol exposure during pregnancy. These alterations are recruited when neonates are re-exposed to the chemosensory attributes of the drug; a result suggesting that ethanol-related learning processes are capable of disrupting the physiological well-being of human neonates. Relative to the emotional reaction to ethanol odor, operationalized through specific facial expressions, prior high levels of ethanol exposure during gestation elicits clear preferences relative towards this sensory cue. This result has been systematically observed in preclinical studies that indicate that fetal processing of ethanol?s sensory attributes is associated with central reinforcing effects of the drug and its principal metabolite. Taken as a whole, it appears that specific physiological and behavioral changes recruited by the olfactory properties of the drug represent clear biomarkers of excessive fetal ethanol exposure.