Background: Neonatal Late-Onset Sepsis (LOS) is a major contributor to adverse neurodevelopmental outcomes, even in the absence of diagnosed meningitis. The mechanisms linking systemic inflammation to neurological impairment in infants remain unclear. Experimental evidence suggests that central nervous system (CNS) involvement may occur through alteration of brain barrier systems. This study aimed to investigate the neonatal blood-cerebrospinal fluid (CSF) barrier, as a dynamic interface between systemic circulation and CNS, using proteomic profiling to assess its functional behaviour, integrity, and associated biochemical processes during systemic inflammation. Methods: In this prospective monocentric pilot study conducted in a tertiary Neonatal Intensive Care Unit, temporally matched CSF and plasma samples were collected from term and preterm infants undergoing evaluation for suspected LOS. Proteomic profiling was performed on 45 paired samples using high-resolution liquid chromatography mass spectrometry. Infants were stratified in three groups based on C-reactive protein (CRP) dynamics (not inflamed, evolving inflammation, and overt inflammation), representing increasing systemic inflammatory burden. Differential protein expression was assessed by ANOVA and t-tests, and functional enrichment analyses were conducted to identify modulated pathways. Results: Significant proteomic modulation was observed, with 57 differentially expressed proteins in CSF and 20 in plasma across CRP dynamics-defined groups. Four proteins - CRP, complement 9 (C9), leucine-rich alpha-2-glycoprotein 1 (LRG1), and alpha-fetoprotein (AFP) - were consistently modulated in both compartments. This pattern supports a model of selective transfer of acute-phase proteins (APPs) from plasma to CSF, indicating regulated blood-CSF barrier permeability rather than overt structural disruption. Functional enrichment analyses revealed negative enrichment of neurogenesis- and axon guidance-related pathways, and positive enrichment of cytoskeleton organization pathways in the CSF proteome with increasing inflammation. Among culture-positive infants, only mannan-binding lectin serine protease 1 (MASP1) was significantly down-regulated in CSF. Given that MASP1 consumption has been associated with disseminated intravascular coagulation in septic patients, its reduction in CSF may reflect inflammation-related neurovascular-coagulation dynamics. Conclusion: Systemic inflammation during suspected LOS is associated with marked and compartment-specific proteomic changes in neonates without meningitis. The findings reveal a dual signature consisting of selective APPs transfer across the blood-CSF barrier and modulation of neurodevelopmental and cytoskeletal pathways in CSF. These results support the concept of functional barrier modulation during neonatal inflammation and provide insight into biochemical mechanisms potentially contributing to subtle brain injury. MASP1 modulation further suggests a possible link between inflammatory and neurovascular-coagulation pathways. Identified proteins represent candidate biomarkers of CNS involvement and warrant further validation in larger cohorts.
Protemic Analysis of Cerobrospinal fluid And Plasma During Neonatal Late-Onset Sepsis Evaluations: Functional Insights into Blood-Cerebrospinal Fluid Barrier Dynamics
VINCI, FRANCESCO
2026-05-27
Abstract
Background: Neonatal Late-Onset Sepsis (LOS) is a major contributor to adverse neurodevelopmental outcomes, even in the absence of diagnosed meningitis. The mechanisms linking systemic inflammation to neurological impairment in infants remain unclear. Experimental evidence suggests that central nervous system (CNS) involvement may occur through alteration of brain barrier systems. This study aimed to investigate the neonatal blood-cerebrospinal fluid (CSF) barrier, as a dynamic interface between systemic circulation and CNS, using proteomic profiling to assess its functional behaviour, integrity, and associated biochemical processes during systemic inflammation. Methods: In this prospective monocentric pilot study conducted in a tertiary Neonatal Intensive Care Unit, temporally matched CSF and plasma samples were collected from term and preterm infants undergoing evaluation for suspected LOS. Proteomic profiling was performed on 45 paired samples using high-resolution liquid chromatography mass spectrometry. Infants were stratified in three groups based on C-reactive protein (CRP) dynamics (not inflamed, evolving inflammation, and overt inflammation), representing increasing systemic inflammatory burden. Differential protein expression was assessed by ANOVA and t-tests, and functional enrichment analyses were conducted to identify modulated pathways. Results: Significant proteomic modulation was observed, with 57 differentially expressed proteins in CSF and 20 in plasma across CRP dynamics-defined groups. Four proteins - CRP, complement 9 (C9), leucine-rich alpha-2-glycoprotein 1 (LRG1), and alpha-fetoprotein (AFP) - were consistently modulated in both compartments. This pattern supports a model of selective transfer of acute-phase proteins (APPs) from plasma to CSF, indicating regulated blood-CSF barrier permeability rather than overt structural disruption. Functional enrichment analyses revealed negative enrichment of neurogenesis- and axon guidance-related pathways, and positive enrichment of cytoskeleton organization pathways in the CSF proteome with increasing inflammation. Among culture-positive infants, only mannan-binding lectin serine protease 1 (MASP1) was significantly down-regulated in CSF. Given that MASP1 consumption has been associated with disseminated intravascular coagulation in septic patients, its reduction in CSF may reflect inflammation-related neurovascular-coagulation dynamics. Conclusion: Systemic inflammation during suspected LOS is associated with marked and compartment-specific proteomic changes in neonates without meningitis. The findings reveal a dual signature consisting of selective APPs transfer across the blood-CSF barrier and modulation of neurodevelopmental and cytoskeletal pathways in CSF. These results support the concept of functional barrier modulation during neonatal inflammation and provide insight into biochemical mechanisms potentially contributing to subtle brain injury. MASP1 modulation further suggests a possible link between inflammatory and neurovascular-coagulation pathways. Identified proteins represent candidate biomarkers of CNS involvement and warrant further validation in larger cohorts.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
