Alpha II-spectrin breakdown products serve as novel markers of brain injury severity in a canine model of hypothermic circulatory arrest.

Abstract

BACKGROUND:

The development of specific biomarkers to aid in the diagnosis and prognosis of neuronal injury is of paramount importance in cardiac surgery. Alpha II-spectrin is a structural protein abundant in neurons of the central nervous system and cleaved into signature fragments by proteases involved in necrotic and apoptotic cell death. We measured cerebrospinal fluid alpha II-spectrin breakdown products (alphaII-SBDPs) in a canine model of hypothermic circulatory arrest (HCA) and cardiopulmonary bypass.

METHODS:

Canine subjects were exposed to either 1 hour of HCA (n = 8; mean lowest tympanic temperature 18.0 +/- 1.2 degrees C) or standard cardiopulmonary bypass (n = 7). Cerebrospinal fluid samples were collected before treatment and 8 and 24 hours after treatment. Using polyacrylamide gel electrophoresis and immunoblotting, SBDPs were isolated and compared between groups using computer-assisted densitometric scanning. Necrotic versus apoptotic cell death was indexed by measuring calpain and caspase-3 cleaved alphaII-SBDPs (SBDP 145+150 and SBDP 120, respectively).

RESULTS:

Animals undergoing HCA demonstrated mild patterns of histologic cellular injury and clinically detectable neurologic dysfunction. Calpain-produced alphaII-SBDPs (150 kDa+145 kDa bands-necrosis) 8 hours after HCA were significantly increased (p = 0.02) as compared with levels before HCA, and remained elevated at 24 hours after HCA. In contrast, caspase-3 alphaII-SBDP (120 kDa band-apoptosis) was not significantly increased. Animals receiving cardiopulmonary bypass did not demonstrate clinical or histologic evidence of injury, with no increases in necrotic or apoptotic cellular markers.

CONCLUSIONS:

We report the use of alphaII-SBDPs as markers of neurologic injury after cardiac surgery. Our analysis demonstrates that calpain- and caspase-produced alphaII-SBDPs may be an important and novel marker of neurologic injury after HCA.

• Authors: Eric S Weiss, Kevin K W Wang, Jeremiah G Allen, Mary E Blue, Lois U Nwakanma, Ming Cheng Liu, Mary S Lange, Jennifer Berrong, Mary Ann Wilson, Vincent L Gott, Juan C Troncoso, Ronald L Hayes, Michael V Johnston, William A Baumgartner
• Journal: The Annals of thoracic surgery (Ann Thorac Surg) Vol. 88 Issue 2 Pg. 543-50 (Aug 2009) ISSN: 1552-6259 [Electronic] Netherlands
• PMID: 19632410 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Spectrin
• Calpain
• Caspases

Topics

• Animals
• Apoptosis (physiology)
• Basal Ganglia (pathology)
• Biomarkers (cerebrospinal fluid)
• Brain Injuries (cerebrospinal fluid, metabolism, pathology)
• Calpain (metabolism)
• Caspases (metabolism)
• Cerebellum (pathology)
• Dentate Gyrus (pathology)
• Dogs
• Electrophoresis, Polyacrylamide Gel
• Heart Arrest, Induced (adverse effects)
• Hypothermia, Induced
• Immunoblotting
• Male
• Models, Animal
• Necrosis (cerebrospinal fluid)
• Parietal Lobe (pathology)
• Spectrin (cerebrospinal fluid)