Biomarkers of Cardiac Injury and Dysfunction in Equine Medicine

A biomarker is a defined characteristic that is considered as an indicator of biologic or pathologic processes, or responses to an exposure or therapeutic intervention. there is an explosive growth in the number and scope of biomarker knowledge in veterinary medicine indicating a highly positive outlook for biomarker researchers and developers. today without biomarkers, the study of biology and medicine is impossible. biomarkers can be anatomical, histological, imaging, genes, mrna, proteins, metabolites, etc. they are classified as prognostic and predictive biomarkers. prognostic biomarkers are any measurement associated with clinical outcome in the absence of therapy, or with the application of a standard therapy that all patients are likely to receive. predictive biomarkers are any measurement associated with response or lack of response to a particular therapy, where response can be defined using any of the clinical endpoints commonly used in clinical trials. there are several applications for biomarkers including for prognosis/diagnosis of disease, staging of disease (severity), monitoring/predicting drug toxicity, monitoring/predicting drug response, establishing disease risk and for clinical trial design. a biomarker should be reliable, quantitative, fully validated, cost efficient, and non-invasive with high diagnostic sensitivity and specificity. most likely the use of multiple biomarkers is required to obtain high sensitivity and specificity. there are challenges in employing biomarkers. application of the analyte, in context as a biomarker, requires deep biologic understanding of where the biomarker arises and is applied, test system, species, or patient, the kinetics and regulation of the biological response, the sensitivity and specificity of the analyte as a biomarker, and other complex biologic factors. it also requires understanding of the assay used to measure, and sources of pre-analytical, analytical, or post analytical variation that can influence quantitation and interpretation. the emphasis should be placed on biomarker assay development and method validation to eliminate the failure of biomarkers that occur in the clinic as a result of poor assay choice and the lack of robust validation. the biomarker method validation process begins with choosing the right assay, followed by developing this assay into a validated method.