Increased maternal/fetal blood S100B levels following systemic endotoxin administration and periventricular white matter injury in preterm fetal sheep.

OBJECTIVE: Intrauterine infection is suggested to cause perinatal brain white matter injury. In the current study, we evaluated whether S100B, a brain damage marker, may be also assessed in maternal bloodstream after white matter injury induced by fetal intravenous application of lypopolisaccharide (LPS) endotoxin. METHODS: Fourteen fetal sheeps were chronically catheterized at a mean gestational age of 107 days. Three days after surgery, fetuses (n = 7) received 500 ng of LPS or 2 mL 0.9% saline (n = 7) intravenously (IV). Lypopolisaccharide and placebo groups were monitored by continuous hemodynamic data recordings and at 6 predetermined time points (control value; 3, 6, 24, 48, and 72 hours after LPS/placebo administration) blood was drawn for laboratory parameters and S100B assessment. Brain damage was evaluated by light microscopy after Klüver-Barrera staining. Selected areas of the periventricular white matter were also examined by electron microscopy. RESULTS: White matter injury was detected in all LPS-treated fetuses, whereas no abnormalities were seen in control animals or in LPS-treated mothers. Maternal and fetal S100B protein levels were significantly higher in the LPS group than in the control group at all monitoring time points (P < .001). The highest fetal-maternal S100B levels were observed at 3-hour time-point (P < .001). CONCLUSIONS: We found that S100B protein is increased in the maternal district in presence of fetal periventricular brain white matter injury induced by endotoxin. The present data offer additional support for S100B assessment in the maternal circulation in pregnancies complicated by intrauterine infection at risk of white matter injury.

Systemic endotoxin administration results in increased S100B protein blood levels and periventricular brain white matter injury in the preterm fetal sheep.

OBJECTIVE: Intrauterine infection is suggested to cause perinatal brain white matter injury. The aim of the present study was to clarify, whether intravenous application of endotoxin results in neuropathological findings and increased blood levels of the S100B protein, which is a consolidated marker of brain injury. METHODS: Twenty-one fetal sheep were chronically catheterized at a mean gestational age of 107+/-1 days (0.7 of gestation). Three days after surgery fetuses received either 100 (n = 9), 500 (n = 5) or 2500 ng (n = 1) lipopolysaccharide (LPS; E. coli; O127:B8, Sigma-Aldrich) or 2 ml 0.9% saline (n = 6) i.v. S100B protein blood levels were assessed before during and after LPS or placebo administration. Brain damage was evaluated by light microscopy. Selected areas of the periventricular white matter were also examined by electron microscopy. RESULTS: Histopathological screening revealed no evidence for cortical neuronal cell damage in both groups. However, LPS treatment resulted in inflammatory infiltrates in all animals and cystic lesions in the periventricular brain white matter in two fetuses. On electron micrographs, infiltrate forming cells appeared to be activated microglia. S100B protein blood levels were significantly higher in the LPS group at 1h (p < 0.01) after LPS injection, peaking at 3h (p < 0.001) and returning to baseline between 12 and 72 h. CONCLUSION: Intravenous application of endotoxin caused focal periventricular brain white matter injury, inflammation and an increase in S100B protein release. It is suggested that longitudinal investigations of S100B protein blood levels offer a tool for the early detection of white matter injury.