Kyorin University

The gut microbiota begins to colonize the host body following birth, develops during the suckling period and changes to the adult type after weaning. The early gut microbiota during the suckling period is thought to have profound effects on the host physiology throughout life but it is still unclear whether early dysbiosis is retained lifelong. Our previous study indicated that chronic nasal inflammation induces dysbiosis of gut microbiota in adult mice. In the present study, we addressed the question as to whether early exposure to chronic nasal inflammation induces dysbiosis, and if so, whether the dysbiosis is retained until adulthood and the sex differences in this effect. Male and female mice received repeated intranasal administration of lipopolysaccharide (LPS) or saline twice a week from P7 to P24 and were weaned at P24. The cecal contents were obtained for 16S rRNA analysis at 2 time points: at 4 weeks (wks), just after weaning, and at maturation to adulthood at 10 wks. The body weight did not differ between saline- and LPS-treated mice till around weaning, suggesting that the mothers' milk was given similarly to all mice. At 4 wks, the beta diversity was significantly different between saline- and LPS-treated male and female mice and the composition of the gut microbiota changed in LPS-treated mice. The abundance of phylum Bacteroidota tended to decrease and that of Firmicutes increased in LPS-treated male mice, while the abundance of Deferribacterota increased in LPS-treated female mice. At 10 wks, the beta diversity was not different between saline- and LPS-treated mice, but the abundance of family Lachnospiraceae significantly decreased in LPS-treated male and female mice by LEfSe analysis. Together, chronic nasal inflammation early in life caused transient and long-term dysbiosis of gut microbiota, which may contribute to the onset and progress of metabolic and neuropsychiatric disorders.

To identify whether histologically confirmed chorioamnionitis (hCAM) is associated with development of retinopathy of prematurity (ROP).

We retrospectively analyzed 2 different cohorts. Cohort 1 was the national database of newborns in Japan born at ≤1500g or <32 weeks' gestation (January 2003 through April 2021, n = 38 013). Cohort 2 was babies born at <1500g from a single institution in Tsuchiura, Japan, (April 2015 through March 2018, n = 118).

For Cohort1, after adjusting for potential confounders, stage III CAM (n = 5554) was associated with lower odds of severe ROP (stage ≥3 or required peripheral retinal ablation) by 14% (OR: 0.86; 95% CI: 0.78-0.94]. CAM of stage I (n = 3277) and II (n = 4319) was not associated with the risk of ROP. For Cohort 2, the odds of severe ROP were significantly reduced in moderate to severe hCAM groups (stage II, OR: 0.06, 95% CI: 0.05-0.82; stage III, OR: 0.10, 95% CI: 0.01-0.84). Neonates with funisitis, comorbidity of hCAM, and a finding of fetal inflammatory response had lower odds of severe ROP (OR: 0.11; 95% CI: 0.01-0.93).

After adjusting for confounders, severe hCAM with fetal inflammatory response was associated with reduced risk of ROP.