Multiplex array proteomics detects increased MMP-8 in CSF after spinal cord injury.
BACKGROUND
A variety of methods have been used to study inflammatory changes in the acutely injured spinal cord. Recently novel multiplex assays have been used in an attempt to overcome limitations in numbers of available targets studied in a single experiment. Other technical challenges in developing pre-clinical rodent models to investigate biomarkers in cerebrospinal fluid (CSF) include relatively small volumes of sample and low concentrations of target proteins. The primary objective of this study was to characterize the inflammatory profile present in CSF at a subacute time point in a clinically relevant rodent model of traumatic spinal cord injury (SCI). Our other aim was to test a microarray proteomics platform specifically for this application.


METHODS
A 34 cytokine sandwich ELISA microarray was used to study inflammatory changes in CSF samples taken 12 days post-cervical SCI in adult rats. The difference between the median foreground signal and the median background signal was measured. Bonferroni and Benjamini-Hochburg multiple testing corrections were applied to limit the False Discovery Rate (FDR), and a linear mixed model was used to account for repeated measures in the array.


RESULTS
We report a novel subacute SCI biomarker, elevated levels of matrix metalloproteinase-8 protein in CSF, and discuss application of statistical models designed for multiplex testing.


CONCLUSIONS
Major advantages of this assay over conventional methods include high-throughput format, good sensitivity, and reduced sample consumption. This method can be useful for creating comprehensive inflammatory profiles, and biomarkers can be used in the clinic to assess injury severity and to objectively grade response to therapy.
Department of Neurosurgery, University of Colorado School of Medicine, Building RC-1 North, Room P18-9400, 12800 E 19th Avenue, Aurora, CO 80045, USA.
Matthew
M
Light
Kenneth H
KH
Minor
Peter
P
DeWitt
Kyle H
KH
Jasper
Stephen J A
SJ
Davies
D000818:Animals; D015415:Biomarkers / Q000134:cerebrospinal fluid / Q000378:metabolism; D002574:Cervical Vertebrae / Q000201:enzymology; D005260:Female; D020784:Matrix Metalloproteinase 8 / Q000096:biosynthesis* / Q000134:cerebrospinal fluid*; D040081:Protein Array Analysis / Q000379:methods*; D040901:Proteomics / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000134:cerebrospinal fluid* / Q000201:enzymology*; D015854:Up-Regulation / Q000502:physiology
D015415:Biomarkers; D020784:Matrix Metalloproteinase 8