[Frontiers in Bioscience S2, 432-438, January 1, 2010]

Increased EEG delta frequency corresponds to chorioamnionitis-related brain injury

Antonio Wenceslao Danilo Gavilanes1,3, Markus Gantert4, Eveline Strackx1,2,3, Luc J. Zimmermann1, Saskia Seeldrayers5, Johan S. H. Vles2, Boris W. Kramer1,3

1Departments of Pediatrics, Neonatology, Maastricht University Medical Center, 2Child Neurology, Maastricht University Medical Center, in collaboration with the School for Oncology and Developmental Biology (GROW), Faculty of Health, Medicine and Life Sciences Maastricht University, The Netherlands, 3School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University and European Graduate School of Neuroscience (EURON), The Netherlands, 4Department of Obstetrics and Gynecology, Klinikum Osnabruck, Osnabruck, Germany and 5Animal Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Animals and surgical procedures
3.2. Intrapartal EEG data sampling and off-line analysis
3.3. Flow cytometric analysis
3.4. Statistical analysis
4. Results
4.1. CFAM amplitude
4.2. CFAM frequency
4.3. FACS activated microglia
4.4. FACS apoptotic cell death
4.5. CFAM vs. FACS variables
5. Discussion
5.1. Clinical relevance of antenatal inflammation
5.2. Inflammatory CNS impact
5.3. CFAM registration
5.4. EEG amplitude analysis
5.5. EEG delta frequency analysis
5.6. Methodological EEG drawbacks and study limitations
5.7. Final remarks
6. Acknowledgements
6. References

1. ABSTRACT

We evaluated the impact of chorioamnionitis on the intrapartal EEG delta frequency in the non-anesthetized preterm sheep. 10 mg intra-amniotic LPS or saline were given 2 or 14 days before preterm birth at gestational day 125. Lambs were delivered by Caesarean section under local anesthesia. A 5-minute EEG depicted delta activity and amplitude, and the relationship between EEG delta activity and both the white matter (WM) and cortical microglial activation and apoptosis was analyzed. EEG delta activity was increased significantly in the 14-day LPS preterm fetuses compared to both preterm control and 2-day LPS animals (p < 0.05). No differences were seen between controls and the 2-day LPS fetuses. A direct association was demonstrated between EEG delta activity and both cortical microglial activation (r = 0,645, p = 0,024) and apoptosis (r = 0,580, p = 0,048), and between delta and WM activated microglia (r = 0,742, p = 0,006) and apoptosis (r = 0,777, p = 0,003). This study is the first to show a relationship between brain dysfunction and chorioamnionitis-related injury at birth.