420 - Comparison of TLR 4 and HMGB1 Protein Expression in Early Stool Collections for Opioid Exposed and Non-Exposed Infants

Poster Number: 420
Publication Number: 420.136

Rebecca C. Barnett, Marshall University Joan C. Edwards School of Medicine, Hurricane, WV, United States; Angela Lewis, Saint Louis University School of Medicine, St. Louis, MO, United States; Qingqing Gong, Washington University in St. Louis School of Medicine, St. Louis, MO, United States; Misty Good, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States; Deborah L. Preston, Marshall University Joan C. Edwards School of Medicine, Huntington, WV, United States; Joseph W. Werthammer, Marshall University Joan C. Edwards School of Medicine, Barboursville, WV, United States

Background: Necrotizing enterocolitis (NEC) remains an important cause of morbidity and mortality in the neonate. We previously described an association between NEC and prenatal opioid exposure with neonatal abstinence syndrome (NAS) in late preterm and full-term neonates (PMID: 32280068). Several inflammatory markers, including high mobility group box 1 (HMGB1) and the innate immune receptor, toll-like receptor 4 (TLR4), have been found to be upregulated in the intestines of infants with NEC, but there have not been studies evaluating expression of these markers in opioid-exposed infants.

Objective: To evaluate TLR4 and HMGB1 expression in the stool of opioid-exposed infants with NAS compared to non-exposed control infants.

Design/Methods: We conducted a prospective cohort study at Cabell Huntington Hospital from August 2020 until June 2021. Enrolled neonates were >36 weeks gestation at birth, without health complications, and were formula fed only. Stool samples were collected on day 2 and day 5-7 of life and were analyzed by one-step RT PCR to evaluate expression of TLR4 and HMGB1. Demographic information was collected and descriptive statistics applied.

Results: 17 patients were enrolled in this study (Nf9 opioid-exposed infants, Nf8 non-exposed controls). TLR4 expression was higher in the stool of the non-exposed group at both time periods, on day 2 (p < 0.0001) and day 5-7 (p=0.036; Mann Whitney). TLR4 expression in the stool significantly decreased at day 5-7 (exposed group p=0.0391, non-exposed p=0.0195) when analyzed using Wilcoxon Matched pair rank test. There was no significant difference in HMGB1 expression in either group, at either time period.Conclusion(s): TLR4 expression in the stool of opioid-exposed infants is significantly decreased compared to non-exposed infants at day 2 and day 5-7 of life. There is no difference in HMGB1 expression in the stool between these groups. Though upregulation of TLR4 has been implicated in the pathogenesis of NEC in preterm infants, based on this early investigation, elevated TLR4 expression in the stool does not appear to explain the higher risk of NEC in opioid exposed infants.
Study Population Characteristics
TLR4 Expression at Day 2 of Life in Control Non-Exposed Infants versus Opioid Exposed InfantsTLR4day2graph.jpeg