Changes in serum indoleamine 2, 3-dioxygenase and kynurenic acid levels in preterm infants with bronchopulmonary dysplasia / 中华围产医学杂志

ABSTRACT

Objective:To explore the changes in serum indoleamine 2, 3-dioxygenase (IDO) and kynurenic acid (KYNA) levels in preterm infants diagnosed with bronchopulmonary dysplasia (BPD).Methods:A nested case-control study was conducted. The inclusion criteria covered premature infants with less than 32 weeks of gestational age within 24 h post-birth, from December 1, 2021, to December 31, 2022, at Children's Hospital of Soochow University. Those diagnosed with BPD were allocated to the BPD group ( n=35). Non-BPD preterm infants matching the BPD cases in terms of gestational age (within one week difference) and birth weight (within a 150 g difference) were selected in a 1∶1 ratio for the control group ( n=35). Serum levels of IDO and KYNA were measured on days 1, 7, 14, and 28 postnatally. Differences in serum IDO and KYNA levels were analyzed between the BPD and control groups and among infants with mild BPD versus moderate-to-severe BPD. The association between serum IDO and KYNA levels with the severity of BPD was also assessed. Statistical analysis was conducted using independent samples t-tests and Spearman's correlation analysis. Results:Elevated levels of serum IDO on days 7, 14, and 28 postnatally [(60.68±9.37) vs. (50.66±10.46), (57.81±11.07) vs. (44.45±8.20), and (50.62±10.77) vs. (41.31±7.74) pg/ml; t=4.21, 5.73, and 4.15, respectively] as well as increased serum KYNA levels on days 14 and 28 [(439.31±41.22) vs. (368.99±68.79), (376.97±45.74) vs. (325.50±60.07) μmol/L; t=5.18 and 4.03, respectively] were observed in the BPD group compared to the control group, with all differences being statistically significant (all P<0.05). Furthermore, positive correlations were observed between serum IDO levels and BPD severity on the 7th, 14th, and 28th days ( r=0.546, 0.495, and 0.502, all P<0.05), as well as between serum KYNA levels and BPD severity on the 14th and 28th days ( r=0.536 and 0.458, both P<0.05). Conclusion:Elevated serum levels of IDO and KYNA in infants with BPD suggest these metabolites may play a role in the pathogenesis and progression of BPD.