242 - Early Intestinal Oxygenation in Preterm Infants is Associated with Early Intestinal Microbiome Diversity

Publication Number: 4238.242

Bineta Lahr, University Medical Center Groningen, Groningen, Groningen, Netherlands; Daphne Klerk, Beatrix Children's Hospital, University Medical Center Groningen, Groningen, Groningen, Netherlands; Celina L. Brunsch, University Medical Center Groningen, Groningen, Groningen, Netherlands; Jan B.F.. Hulscher, university medical center groningen, Groningen, Groningen, Netherlands; Elisabeth M.W.. Kooi, Beatrix Children's Hospital, University Medical Center Groningen, Groningen, Groningen, Netherlands

Background: Gut microbial colonization essential for neonatal development. Preterm infants have reduced bacterial diversity and an increased abundance of potentially pathogenic bacteria, which may adversely affect health outcomes. While adequate cerebral and intestinal oxygenation are crucial for early organ development, their relationship with gut microbiome composition is unclear.

Objective: To investigate the association between cerebral and intestinal oxygenation, measured by near-infrared spectroscopy (NIRS), and the gut microbiome in very preterm infants.

Design/Methods: Infants with a gestational age (GA) ≤ 30 weeks and/or birth weight (BW) ≤ 1000g were prospectively included. On the first postnatal day, we measured mean regional splanchnic oxygen saturation (rsSO₂), mean regional cerebral oxygen saturation (rcSO₂), variability of rsSO₂ (rsCoVAR = SD/mean), and the splanchnic-cerebral oxygenation ratio (SCOR=rsSO₂/rcSO₂) at two-hour intervals. Shotgun metagenomic sequencing was applied to infant fecal samples collected throughout the first eight weeks of life, and alpha diversity (Shannon diversity index) was calculated across all collected samples to assess associations between early NIRS measurements and later microbiome composition. All analyses were corrected for false discovery using the Benjamin-Hochberg procedure.

Results: 70 Infants were included (median GA: 27 weeks, range 23 + 6 - 30 + 0 weeks; median BW: 960 grams, range 550 - 1594 grams). On the first postnatal day, lower rsSO₂, lower SCOR, and higher rsCoVAR were significantly associated with higher alpha diversity across all samples (N = 293; mean 4.2 samples per infant) (all p < 0.05). No association was observed with rcSO₂ (p = 0.55) (Figure 1).

Conclusion(s): Intestinal oxygenation on the first postnatal day is associated with higher alpha diversity in the gut microbiome. These findings suggest that early gut oxygenation is associated with an increased microbial diversity, possibly reflecting more active or better-regulated intestinal vascular function. Further research is needed to confirm and explore this association and its long-term clinical implications.

Shannon diversity across all fecal samples during the first eight weeks of life in preterm infants, stratified by cerebral and intestinal oxygenation measurements on the first postnatal day.
A. Regional splanchnic oxygen saturation (rsSO₂): significantly higher diversity at < 54% vs. ≥ 54% (p < 0.001). B. Regional cerebral oxygen saturation (rcSO₂): no significant difference between < 78% and ≥ 78% (p = 0.55). C. RsSO₂ variability (rsCoVAR = SD/mean): significantly higher diversity at ≥ 0.18 vs. < 0.18 (p = 0.014). D. Splanchnic-cerebral oxygenation ratio (SCOR): significantly higher diversity at <0.66 vs. ≥ 0.66 (p = 0.005). *Indicates p < 0.05, **p < 0.01, ***p < 0.001. Boxplots show medians, hinges (25th - 75th percentiles), and whiskers up to 1.5× the interquartile range. Cut-offs were based on median values. For rsCoVAR, a cutoff of 0.18 was used based on clinical relevance and significance, although the median value was 0.17 (p = 0.066).