Abstract
Background
Treatment of neonatal peritonitis and sepsis is challenging. Following infection, neutrophils elaborate neutrophil extracellular traps (NETs)—extracellular lattices of decondensed chromatin decorated with antimicrobial proteins. NETs, however, can augment pathogenic inflammation causing collateral damage. We hypothesized that NET inhibition would improve survival in experimental neonatal infectious peritonitis.
Methods
We induced peritonitis in 7 to 10-day-old mice by intraperitoneal injection with cecal slurry. We targeted NETs by treating mice with neonatal NET-Inhibitory Factor (nNIF), an endogenous NET-inhibitor; Cl-amidine, a PAD4 inhibitor; DNase I, a NET degrading enzyme, or meropenem (an antibiotic). We determined peritoneal NET and cytokine levels and circulating platelet–neutrophil aggregates. Survival from peritonitis was followed for 6 days.
Results
nNIF, Cl-amidine, and DNase I decreased peritoneal NET formation and inflammatory cytokine levels at 24 h compared to controls. nNIF, Cl-amidine, and DNase I decreased circulating platelet–neutrophil aggregates, and NET-targeting treatments significantly increased survival from infectious peritonitis compared to controls. Finally, nNIF administration significantly improved survival in mice treated with sub-optimal doses of meropenem even when treatment was delayed until 2 h after peritonitis induction.
Conclusions
NET inhibition improves survival in experimental neonatal infectious peritonitis, suggesting that NETs participate pathogenically in neonatal peritonitis and sepsis.
Impact
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1.
Neutrophil extracellular trap formation participates pathogenically in experimental neonatal infectious peritonitis.
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2.
NET-targeting strategies improve outcomes in a translational model of neonatal infectious peritonitis.
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3.
NET inhibition represents a potential target for drug development in neonatal sepsis and infectious peritonitis.
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Data availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
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Funding
This work was supported in part by the US NIH (R01HD093826 to C.C.Y.—NICHD; K01AG059892 to R.A.C.—NIA), PEEL Therapeutics, Inc. (Sponsored Research Agreement to C.C.Y.), the American Heart Association (2021Post830138 to F.D. and 2022Post906231 to I.P.), and by the University of Utah Department of Pediatrics, Division of Neonatology.
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C.C.Y. and F.D. conceived the project and designed the experiments. F.D., J.L.R., I.P., J.L.C., C.V.d.A., and M.J.C. performed experiments and analyzed data. F.D., M.J.C., R.A.C., and C.C.Y. wrote and edited the manuscript for important intellectual content.
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C.C.Y. authors a US patent (patent 232,023 B2) held by the University of Utah for the use of NET-inhibitory peptides for the “treatment of and prophylaxis against inflammatory disorders,” for which PEEL Therapeutics, Inc. holds the exclusive license. The other authors declare that no additional conflict of interest exists.
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Denorme, F., Rustad, J.L., Portier, I. et al. Neutrophil extracellular trap inhibition improves survival in neonatal mouse infectious peritonitis. Pediatr Res 93, 862–869 (2023). https://doi.org/10.1038/s41390-022-02219-0
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DOI: https://doi.org/10.1038/s41390-022-02219-0
