An NMR Metabolomics Study of Elk Inoculated with Chronic Wasting Disease

Abstract

Chronic wasting disease (CWD) is a fatal neurodegenerative disease affecting both farmed and wild cervids, specifically deer and elk, and is a member of the larger family of prion diseases. Prion disease transmission is believed to occur through exposure to infectious prion material—a misfolded and infectious form of the prion protein that is normally present in the host. Chronic wasting disease is endemic to regions of central North America and infectious material can persist for long periods in the environment, posing challenges for remediation and monitoring. The current methods of detection are relatively invasive, require the host animal to be in intermediate to late stages of disease incubation, and are not without risk to those collecting samples. The potential for a blood test that could identify key biomarkers of disease incubation is of great interest. Serum from elk (Cervus elaphus) (n = 4) was collected on a monthly schedule before, and following, oral inoculation of CWD-positive homogenate, and collection continued until clinical signs were apparent. Blood was collected on the same schedule for a group of control animals (n = 2) housed under identical conditions. Targeted profiling, using ¹H-nuclear magnetic resonance (NMR) spectroscopy, of serum metabolites was used to yield metabolite identification as well as quantitation. Hierarchical multivariate statistical orthogonal partial least-squares (O-PLS) models were generated to identify predictive components in the data. Due to the duration of the study (25 mo) a significant aging component was taken into account during analysis. Several metabolites were correlated with aging in elk inoculated with CWD, but not in the control group.

Acknowledgments

CWD-positive elk tissue was provided by Dr A. Balachandran (Canadian Food Inspection Agency, Fallowfield). We acknowledge Gavin E. Duggan for some sample preparation and assistance with statistical analysis, and Dr. Aalim Weljie for advice on data analysis and interpretation. Operating support for this research project was provided by a grant from the Canadian Genetics Disease Network and the Alberta Agricultural Research Institute. HJV holds a Scientist award from the Alberta Heritage Foundation for Medical Research. MJP was the recipient of an Alberta Ingenuity Fund Studentship and currently holds Canadian Institutes of Health Research (CIHR), CIHR-THURST (training grant in Health Research Using Synchrotron Techniques), and SHRF (Saskatchewan Health Research Foundation) postdoctoral fellowships.