Gestational and postnatal modulation of esophageal sphincter reflexes in human premature neonates.
BACKGROUND
Effects of gestational age (GA) and postnatal maturation on upper and lower esophageal sphincter (UES and LES) reflex development remain unclear. We hypothesized very-preterm (VPT) born neonates (< 32 wk GA) have delayed maturation of UES contractile reflex (UESCR) and LES relaxation reflex (LESRR) vs. preterm (PT) born (32-37 wk GA) neonates.


METHODS
Using provocative manometry, effects of 1,263 graded mid-esophageal stimuli (air, liquid) on sensory-motor characteristics of UESCR and LESRR were investigated in 24 VPT-born and 12 PT-born neonates (37.8 ± 0.6 vs. 38.9 ± 0.4 wk postmenstrual age respectively, P = 0.14).


RESULTS
In response to liquid stimuli (vs. air), VPT-born neonates displayed prolonged UESCR and LESRR response latencies (P < 0.001) and prolonged UESCR and LESRR durations (P < 0.01); unlike PT-born neonates, who exhibit prolonged LESRR response latency (P < 0.01), but similar UESCR and LESRR durations (P = 0.2). Differences were noted in LESRR duration in VPT vs. PT neonates for air stimuli (P = 0.04). With liquid stimuli, increasing GA was associated with decreasing response onset latencies to UESCR and LESRR (P < 0.05), and increasing LESRR duration (P = 0.02).


CONCLUSIONS
Using GA as categorical or continuous variable, vagus-mediated mechano-sensitive and liquid-sensitive reflex characteristics of UESCR and LESRR are distinct; LESRR differs with varying intrauterine maturation suggesting inhibitory modulation progresses with advancing maturation.
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|The Neonatal Aerodigestive & Pulmonary Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|Divisions of Neonatology, Pediatric Gastroenterology and Nutrition, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.
Sudarshan R
SR
Jadcherla
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.
Theresa R
TR
Shubert
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|The Neonatal Aerodigestive & Pulmonary Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|Divisions of Neonatology, Pediatric Gastroenterology and Nutrition, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.
Manish B
MB
Malkar
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.
Swetha
S
Sitaram
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|The Neonatal Aerodigestive & Pulmonary Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.
Rebecca K
RK
Moore
Center for Biostatistics, The Ohio State University College of Medicine, Columbus, Ohio.
Lai
L
Wei
Center for Biostatistics, The Ohio State University College of Medicine, Columbus, Ohio.
Soledad
S
Fernandez
The Neonatal and Infant Feeding Disorders Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|The Neonatal Aerodigestive & Pulmonary Program, Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio.|Division of Respiratory Medicine, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.
Robert G
RG
Castile
D000367:Age Factors; D002657:Child Development; D049630:Esophageal Sphincter, Lower / Q000294:innervation*; D049631:Esophageal Sphincter, Upper / Q000294:innervation*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008365:Manometry; D040542:Mechanotransduction, Cellular; D011312:Pressure; D011930:Reaction Time; D012018:Reflex; D013997:Time Factors; D014630:Vagus Nerve / Q000503:physiopathology*