Abstract
Introduction: Mechanical ventilation (MV) can cause injury to the lungs and distal organs. We hypothesize that lung-protective MV causes neural inflammation with activation of hippocampal astrocytes. Astrocytes have an essential function in neuronal connection and brain inflammation. Once activated, these cells assist in propagating the inflammatory cascade in the central nervous system. Preclinically, deficits in cognitive function have been associated with an increased number of reactive astrocytes in the CA1 hippocampal area in rodents undergoing MV. The percentage of reactive astrocytes in the hippocampus has not been quantified after 50 hours of lung-protective MV. This data could be used to the development of cognitive impairment after MV.
Methods: Six human-size pigs with non-injured lungs were subjected to lung-protective MV for 50 hours (MV group). Six additional never-ventilated pigs were used as a control group (NV group). Lung-protective MV was defined as: tidal volume 8ml/kg, peak pressure <30 cmH2O and PEEP of 5 mmHg. Three hippocampal regions were analyzed; dentate gyrus (DG), CA3 and CA1. Glial Fibrillary Acid Protein (GFAP) was used to identify reactive astrocytes, and the cells were counted by IMAGEJ.
Results: The percentages of reactive astrocytes in the DG, CA3 and CA1 combined were significantly higher in the MV group than NV group (26% (130,571/502,195) vs. 11% (44,686/406,235)) (p=0.002). MV group showed higher percentages of reactive astrocytes in each hippocampal region; DG 25% (MV) vs. 10% (NV) (p=0.17); CA3: 22% (MV) vs. 8% (NV) (p<0.01); CA1: 30% (MV) vs. 13% (NV) (p<0.01).
Conclusion: Lung-protective MV for 50 hours in pigs leads to activation of hippocampal astrocytes.
Footnotes
Cite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2754.
This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2020