2016 ACVIM Forum Research Abstract Program

Peak plasma concentrations (C pk ) at the end of the distribution phase were 31.7 AE 4.4 µg/mL in young and 32 AE 2.2 µg/mL in aged horses (P = 0.901), while gentamicin trough levels reached 2 µg/mL (common MIC for equine pathogens) at 6.1 AE 1.2 and 7.3 AE 1.5 hours, respectively (P = 0.09). Considering an expected post-antibiotic effect of ≤8 hours, dosing adjustments are likely required to meet therapeutic needs in both study groups. The innate immune response to bacterial lipopolysaccharide (LPS) mediated by toll-like receptor 4 (TLR4) contributes substantially to the morbidity of a number of important equine disease syndromes including gastrointestinal disease and neonatal sepsis, and contributes to other chronic pro-inflammatory states. Micro-RNAs (miRNAs) are small non-coding RNA molecules 17-25 nucleotides in length that function as post-transcriptional regulators of gene expression. miRNAs have recently been found to have a central role in the modulation of the TLR4 signaling cascade in other species, and altered expression has been implicated in the pathogenesis of inflammatory diseases. Limited information is available on miRNA expression in horses, and there is no published data on expression in equine inflammatory cells. This objective of this study was to use next generation sequencing to characterize the basal miRNA transcriptome in isolated equine peripheral blood mononuclear cells, and to test the hypothesis that LPS would induce differential expression of miRNAs.