Exploring Spinal Cord Protection by Remote Ischemic Preconditioning: An Experimental Study.
BACKGROUND
Paraplegia is one of the most severe complications occurring after the repair of thoracic and thoracoabdominal aortic aneurysms. Remote ischemic preconditioning (RIPC) has been shown to mitigate neurologic damage, and this study assessed its efficacy in preventing spinal cord ischemia.


METHODS
The study randomized 16 female pigs into an RIPC group (n = 8) and a control group (n = 8). The RIPC group underwent four cycles of 5-minute ischemia-reperfusion episodes by intermittent occlusion of the left iliac artery. All animals underwent systematic closure of the left subclavian artery and segmental arteries of the descending thoracic aorta to the level of diaphragm. Motor-evoked potential monitoring was performed in both hind limbs. Continuous electrocardiogram and hemodynamics were monitored, and pulmonary artery blood samples were collected. A neurologic assessment was performed 6 hours after the procedure. The thoracic and lumbar portions of the spinal cord were collected for histologic and immunohistochemical analysis.


RESULTS
The bilateral motor-evoked potential amplitude responses were higher in the RIPC group (p < 0.05) than in the control group; the difference was detected already before spinal cord ischemia. Paraplegia occurred in 1 control animal. Immunohistochemical total scores of antioxidant response regulator nuclear factor erythroid 2-related factor 2 were better in the RIPC group (11.0; range, 8.5 to 14.0) than in the control group (5.2; range, 1.0 to 9.0; p = 0.023).


CONCLUSIONS
RIPC induces electrophysiologic changes in the central nervous system that may confer spinal cord protection extending the resistance to ischemia. The significantly higher nuclear factor erythroid 2-related factor 2 scores suggest better neuronal cell protection against oxidative stress in the RIPC group.
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Johanna
J
Herajärvi
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Tuomas
T
Anttila
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Henna
H
Sarja
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Caius
C
Mustonen
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Henri
H
Haapanen
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Tuomas
T
Mäkelä
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Fredrik
F
Yannopoulos
Department of Clinical Neurophysiology, Medical Research Center Oulu, Oulu University Hospital and Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Finland.
Tuomo
T
Starck
Department of Clinical Neurophysiology, Medical Research Center Oulu, Oulu University Hospital and Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Finland.
Mika
M
Kallio
Department of Pathology, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
Hannu
H
Tuominen
Department of Obstetrics and Gynaecology, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
Ulla
U
Puistola
Department of Oncology and Radiotherapy, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
Peeter
P
Karihtala
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Kai
K
Kiviluoma
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland.
Vesa
V
Anttila
Research Unit of Surgery, Anesthesia and Intensive Care, University of Oulu and Medical Research Center, Oulu, Finland; Department of Cardiac Surgery, Heart and Lung Center, Helsinki University Central Hospital, Helsinki University Hospital, Helsinki, Finland. Electronic address: tatu.juvonen@hus.fi.
Tatu
T
Juvonen
D000818:Animals; D019054:Evoked Potentials, Motor; D005260:Female; D007150:Immunohistochemistry; D019194:Ischemic Preconditioning; D051267:NF-E2-Related Factor 2 / Q000032:analysis; D020760:Spinal Cord Ischemia / Q000517:prevention & control*; D013552:Swine
D051267:NF-E2-Related Factor 2