Alteration of immunologic responses on peripheral blood in the acute phase of ischemic stroke: blood genomic profiling study

Objective: Peripheral blood cells and inflammatory mediators have a detrimental effect on brain during cerebral ischemia. We investigated the immunologic changes on peripheral blood in the acute phase of ischemic stroke using RNA microarray.

Methods: mRNA microarray and real time-polymerase chain reaction (RT-PCR) for genes of interest in microarray data were analyzed in 12 stroke patients and 12 controls. Plasma matrix metalloproteinase-9 (MMP-9) concentrations were measured in 120 stroke patients and 82 controls.

Results: In microarray analysis, a total of 11 genes of interest showed different expression in patients with ischemic stroke. The three most highly expressed genes were C19orf59 (chromosome 19 open reading frame 59), MMP9 and IL18RAP (interleukin-18 receptor accessory protein), whereas gene with the lowest expression was GNLY (granulysin). The expression patterns of three selected genes (MMP9, IL18RAP and GNLY) were validated by RT-PCR. The plasma concentration of MMP-9 was significantly elevated in the stroke patients, and showed a weakly positive correlation with infarct volume. Gene set enrichment analysis (GSEA) showed that gene sets related to immunity and defense, signal transduction, transport and cell adhesion were significant in acute ischemic stroke.

Conclusions: In the peripheral blood, numerous genes of inflammatory mediators, including MMP9, IL18RAP and GNLY, are altered in the acute phase of ischemic stroke. This stroke-specific gene expression profiling provides valuable information about the role of peripheral inflammation to the pathophysiological mechanism of ischemic stroke.