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Hughes JL, Beech JS, Jones PS, Wang D, Menon DK, Aigbirhio FI, Fryer TD, Baron JC. Early-stage 11C-Flumazenil PET predicts day-14 selective neuronal loss in a rodent model of transient focal cerebral ischemia. J Cereb Blood Flow Metab 2020; 40:1997-2009. [PMID: 31637947 PMCID: PMC7786851 DOI: 10.1177/0271678x19883040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Predicting tissue outcome early after stroke is an important goal. MRI >3 h accurately predicts infarction but is insensitive to selective neuronal loss (SNL). Previous studies suggest that chronic-stage 11C-flumazenil PET (FMZ-PET) is a validated marker of SNL in rats, while early-stage FMZ-PET may predict infarction. Whether early FMZ-PET also predicts SNL is unknown. Following 45-min distal MCA occlusion, adult rats underwent FMZ-PET at 1 h and 48 h post-reperfusion to map distribution volume (VT), which reflects GABA-A receptor binding. NeuN immunohistochemistry was performed at Day 14. In each rat, VT and %NeuN loss were determined in 44 ROIs spanning the hemisphere. NeuN revealed isolated SNL and cortical infarction in five and one rats, respectively. In the SNL subgroup, VT-1 h was mildly reduced and only weakly predicted SNL, while VT-48 h was significantly increased and predicted SNL both individually (p < 0.01, Kendall) and across the group (p < 0.001), i.e. the higher the VT, the stronger the SNL. Similar correlations were found in the rat with infarction. Our findings suggest GABA-A receptors are still present on injured neurons at the 48 h timepoint, and the increased 48 h VT observed here is consistent with earlier rat studies showing early GABA-A receptor upregulation. That FMZ binding at 48 h was predictive of SNL may have clinical implications.
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Affiliation(s)
- Jessica L Hughes
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - John S Beech
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, UK
| | - P Simon Jones
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Dechao Wang
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - David K Menon
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Franklin I Aigbirhio
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Tim D Fryer
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Jean-Claude Baron
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Inserm U1266, Paris Descartes University, Sainte-Anne Hospital, Paris, France
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