Xiaofeng Jia, MD, MS, PhD, FCCM
Professor
University of Maryland School of Medicine
Baltimore, MD
Disclosure information not submitted.
Zhuoran Wang, MD, MS
Dr.
University of Maryland School of Medicine, United States
Disclosure information not submitted.
Songyu Chen, MD, PhD
Dr.
University of Maryland School of Medicine, United States
Disclosure information not submitted.
Mark Smith, PhD
Professor
University of Maryland School of Medicine, United States
Disclosure information not submitted.
Title: Effect of Graded Hypothermia on Cerebral Glucose Spatiotemporal Characteristics after Cardiac Arrest
Introduction: Cardiac arrest (CA) is a fatal disease with high rates of neurological impairment. To date, therapeutic hypothermia (targeted temperature management, TTM), is the only strategy with solid clinical evidence. However, there are still controversies on the implementation protocol of TTM, particularly on the depth of TTM, with a lack of elucidated underlying therapeutic mechanisms. Previous animal studies using positron emission tomography (PET), including ours, mostly focused on the changes of cerebral glucose metabolism after hypoxic-ischemic injury, and the relationship between the trend of glucose metabolism and neurological prognosis. There is a lack of research on the temporal and spatial characteristics of glucose metabolism under TTM, particularly under different targeted temperatures. In this study, we compared the effects of different levels of TTM on functional outcomes, the temporal and spatial characteristics of cerebral glucose metabolism, and oligodendrocyte network function after CA, contributing to the optimal depth of TTM treatment.
Methods: Six Wistar rats subjected to 8 min asphyxia-CA were randomly divided into 33° C or 35° C TTM group (N=3). We investigated the spatiotemporal characteristics of cerebral glucose metabolism after CA by 18F-FDG using MicroPET/CT. Myelin Basic Protein (MBP) immunofluorescence staining was used to assess the acute injury and recovery of oligodendrocytes. Functional recovery was evaluated daily using the neurological deficit score (NDS) until 72hr after CA.
Results: There was a significant improvement in functional recovery by NDS (p < 0.05) in the 33° C TTM group compared with the 35° C TTM group. Glucose metabolism analysis showed that the glucose metabolism of the 33° C TTM group was higher than that of the 35° C TTM group early after resuscitation (within 10 minutes). Immunofluorescence analysis showed that positive MBP signals in subcortical white matter and hippocampus in the 33° C TTM group were more than in the 35° C TTM group (p < 0.05).
Conclusions: Compared to 35° C TTM, 33° C TTM changed the spatiotemporal characteristics of brain glucose metabolisms with improved neurological function, which may be through the participation of oligodendrocytes.
Supported in part by the NINDS R01NS110387 and NHLBI R01HL118084 (both to X Jia).