- 2017 - Pilot Grant
Biomarkers capable of assessing the tissue healing capacity of orthopedic trauma patients are desperately needed, and would be extremely valuable for physicians needing to make critical treatment decisions with a huge impact on the patient, such as limb amputation versus limb salvage. Identification of useful biomarkers from human patient cohorts is difficult due to population and injury heterogeneity, thus we propose identifying candidate biomarkers from non-human vertebrates capable of varying degrees of limb regeneration (salamander and mouse). This is a novel and powerful approach to rapidly identify and evaluate candidate tissue-healing biomarkers with the potential of being translated to orthopedic trauma patients.
This proposal is a pilot study for an eventual biomarker screening pipeline: 1) identify putative biomarkers from our salamander limb regeneration study; 2) assess expression levels of putative biomarkers during mouse digit tip regeneration, an innate form of complex tissue regeneration in mammals, and determine if protein levels are detectable in mouse blood; 3) determine the utility of the putative biomarkers in orthopedic trauma patients by quantifying biomarker protein levels in human patients’ serum. In our recent salamander limb regeneration study, we identified 159 differentially-regulated genes that we intend in the long-term to systematically evaluate as candidate biomarkers7. As a proof of principle, this pilot study will focus on one of these candidates, Kazd1. In our study, we showed Kazd1, a secreted factor, is required for salamander limb regeneration and have demonstrated its local upregulation in mouse digits following amputation. We now aim to determine if Kazd1 levels are increased in serum levels in mice undergoing regeneration, and subsequently screen human limb trauma patients’ serum for expression of Kazd1 to correlate with their healing outcomes.
Aim 1: Determine the expression and blood serum levels of Kazd1 during mouse digit tip regeneration.
- We will characterize the expression of Kazd1 mRNA and Kazd1 protein throughout mouse digit tip regeneration and compare to unamputated digit tips.
- We will assess the utility of Kazd1 as a biomarker by quantifying Kazd1 protein levels in serum during mouse digit tip regeneration as compared to baseline levels.
Aim 2: Determine if Kazd1 can serve as a biomarker for successful healing in human orthopedic trauma patients.
- We will quantify baseline Kazd1 protein serum levels in a cohort of control patients.
- We will quantify Kazd1 serum levels in a cohort of patients having undergone orthopedic trauma to correlate with quality of post-trauma tissue healing.
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