Search

ProblemNeonatal abstinence syndrome (NAS) affects opioid exposed infants, and is occurring at increasing rates. NAS develops after the discontinuation of prolonged fetal opioid exposure and is defined by the expression and increased severity of a specified cluster of symptoms. The expression and severity of NAS determines the treatment an infant receives. The symptoms of NAS can be highly variable in expression and severity and the cause for this variability is not well known. One potential factor that may play a particularly important role in influencing NAS symptom variability is the gut microbiota, the collective organisms contained within in the gut.MethodsThis dissertation study was based on the scientific premise that NAS symptom expression and severity is regulated in part by the gut microbiota through the microbiota-gut-brain axis. The overall goals of the study were to determine differences in the gut microbiota of infants with NAS and those without NAS, and to explore relationships between infant gut microbiota and symptom expression and severity of NAS. A non-experimental, cross-sectional approach was used to examine the differences in the gut microbiota and, a longitudinal non-experimental approach with repeated measures was used to determine the relationship between the gut microbiota and NAS symptoms. We collected symptom data using the Finnegan Neonatal Abstinence Scoring Tool (Finnegan) and Neonatal Pain Agitation and Sedation Scale (N-PASS), and also collected stool samples for 16S microbiome sequencing. ResultsAlpha diversity results of the Faith’s Phylogenetic Diversity showed significant differences between the NAS and comparison groups at enrollment (t = 2.457, p = .035, mean difference = .562, 95% CI [.048, 1.08]). Beta diversity differences were found between the NAS group and the comparison group. Adonis (PERMANOVA) results confirmed these differences (r2 = .079, p = .021). Differential abundance results found 18 taxa that were less abundant in the infants with NAS. Positive relationships were found between Escherichia-Shigella and Bacteriodes and the Finnegan measure (r = .45, p = .20, 95% CI [.107, .697]), and the N-PASS measure (r = .51, p = .02, 95% CI [.183, .735]). No differences in alpha diversity or beta diversity were found between the enrollment and discharge measures in the NAS group. DiscussionThe differences found in alpha and beta diversity between the groups of infants with NAS and the group of infants without NAS are likely due to other differences between the groups including birth mode and feeding differences. The findings of increased Escherichia-Shigella and Bacteroides related to increased symptom scores in the infants with NAS may also be influenced by birth mode and type of feeding.ConclusionTo date, no published studies have explored the gut microbiota as a factor in the symptom severity and expression in NAS. The preliminary evidence from this study provide guidance for the development of future research.