Proteomic Profiling of the Amniotic Fluid to Detect Inflammation, Infection, and Neonatal Sepsis

Abstract

BackgroundProteomic analysis of amniotic fluid shows the presence of biomarkers characteristic of intrauterine inflammation. We sought to validate prospectively the clinical utility of one such proteomic profile, the Mass Restricted (MR) score.Methods and FindingsWe enrolled 169 consecutive women with singleton pregnancies admitted with preterm labor or preterm premature rupture of membranes. All women had a clinically indicated amniocentesis to rule out intra-amniotic infection. A proteomic fingerprint (MR score) was generated from fresh samples of amniotic fluid using surface-enhanced laser desorption ionization (SELDI) mass spectrometry. Presence or absence of the biomarkers of the MR score was interpreted in relationship to the amniocentesis-to-delivery interval, placental inflammation, and early-onset neonatal sepsis for all neonates admitted to the Newborn Special Care Unit (n = 104). Women with “severe” amniotic fluid inflammation (MR score of 3 or 4) had shorter amniocentesis-to-delivery intervals than women with “no” (MR score of 0) inflammation or even “minimal” (MR score of 1 or 2) inflammation (median [range] MR 3–4: 0.4 d [0.0–49.6 d] versus MR 1–2: 3.8 d [0.0–151.2 d] versus MR 0: 17.0 d [0.1–94.3 d], p < 0.001). Nonetheless, a “minimal” degree of inflammation was also associated with preterm birth regardless of membrane status. There was a significant association between the MR score and severity of histological chorioamnionitis (r = 0.599, p < 0.001). Furthermore, neonatal hematological indices and early-onset sepsis significantly correlated with the MR score even after adjusting for gestational age at birth (OR for MR 3–4: 3.3 [95% CI, 1.1 to 9.2], p = 0.03). When compared with other laboratory tests routinely used to diagnose amniotic fluid inflammation and infection, the MR score had the highest accuracy to detect inflammation (white blood cell count > 100 cells/mm3), whereas the combination of Gram stain and MR score was best for rapid prediction of intra-amniotic infection (positive amniotic fluid culture).ConclusionsHigh MR scores are associated with preterm delivery, histological chorioamnionitis, and early-onset neonatal sepsis. In this study, proteomic analysis of amniotic fluid was shown to be the most accurate test for diagnosis of intra-amniotic inflammation, whereas addition of the MR score to the Gram stain provides the best combination of tests to rapidly predict infection.

Soluble TLR2 Is Present in Human Amniotic Fluid and Modulates the Intraamniotic Inflammatory Response to Infection

“…Our results are slightly different from the previous reports, which communicate that the sTLR2 system is comprised of six polypeptides (83, 66, 50, 40, 38 and 25 kDa) in human breast milk and plasma (15), and three polypeptides (55,40, and 27 kDA) in the human parotid saliva (14). In our study we showed that the 98-kDa polypeptide corresponds to the full-length transmembrane TLR2 by using as control placental villous tissue, which lacks the two amniotic fluid isoforms attributable to sTLR2.…”

Persistent Cytomegalovirus Infection in Amniotic Membranes of the Human Placenta

“…In conclusion, our studies of placentas from congenital infection and primary cells isolated from various donors and placentas from mid-gestation and late gestation suggest that persistent HCMV infection in fetal membranes could promote inflammation 20,21 and contribute to preterm labor and delivery. 27 Understanding the basis for persistent infection in AmEpCs could lead to therapeutic strategies to prevent congenital disease and pregnancy complications by targeting viral functions that promote persistence and enhancing host antiviral responses that suppress infection.…”

Nucleated red blood cells are a direct response to mediators of inflammation in newborns with early-onset neonatal sepsis

“…[32] In an effort to avoid unnecessary antibiotic administration, attention has turned toward new diagnostic approaches such as the description of biomarkers and hematological indices designed to identify neonates at risk for sepsis and poor outcome. [21,28,30] The importance of this concept is predicated by studies which demonstrate that general hematological indices and NRBCs are good predictors of short term neonatal outcome, independent of gestational age or birth weight. [4,33,34] This suggests that at birth, description of hematological indices and serologic markers even in the absence of positive cultures carries not only diagnostic and prognostic value, but also provides insight into the pathophysiology of fetal adaptation to a microbial inflammatory attack.…”

“…[21] Briefly, the amniotic fluid proteomic fingerprint, the Mass Restricted (MR) score, was generated immediately following the retrieval of amniotic fluid. The MR score provides qualitative information regarding the presence or absence of inflammation.…”