Gene expression analysis of peripheral blood mononuclear cells from acute stroke patients

Background and purpose: Two studies have recently analyzed the gene expression profile of circulating cells in patients with acute ischemic stroke (Moore et al 2005; Tang et al 2006). Both studies presented lists of genes that were differentially expressed in white cells upon stroke. However, there was virtually no overlap between the findings of the two studies.

Methods: We analyzed the expression profile of from peripheral blood mononuclear cells (PBMCs) and evaluated the expression of functional gene groups (not single genes). RNA from PBMCs of 20 acute stroke patients was analyzed with Affymetrix GeneChips. The observed gene expression profile during acute stroke was compared with data from 15 patients with acute brain injury, 15 stroke survivors and 15 healthy subjects without cardiovascular risk factors.

Results: Acute stroke was accompanied by significant up- and down-regulation of genes in PBMCs. Strongest differential gene expression was restricted to few ontologic gene groups. Particularly some genes involved in the inflammatory response and that are also induced by bacterial lipopolysaccharide (LPS) were more than 50% up-regulated (G1P3, FOS, CYBB, FPRL1, BCL6, TLR2 and C3AR1 or down-regulated (IL18RAP) in circulating cells during acute stroke. Genes that we found differentially regulated during acute stroke were similarly up- or down-regulated in patients with brain injury. Our data were compared with data from two earlier studies on gene expression in circulating cells from acute stroke patients.

Conclusions: Acute stroke is accompanied with a significantly differential gene expression response in PBMCs. Our findings partially overlap with findings from earlier studies by Moore et al and Tang et al. However, the transcriptome of the circulating cells upon ischemic stroke is not stroke specific and closely resembles the transcriptome of circulating cells from brain injury patients.