Abstract 2874: Functional Polymorphisms in Toll-like Receptor 4 Predict Worse Outcome in Acute Ischemic Stroke Patients
Background: Toll-like receptor-4 (TLR4) plays a central role in the pathophysiology of acute ischemic stroke (AIS). Specific single nucleotide polymorphisms (SNPs) in TLR4 including 1063 A/G [Asp299Gly] and 1363 C/T [Thr399Ile] alter immune cell responsiveness to lipopolysaccharide (LPS) and are associated with increased rates of infection. The effect of these TLR4 SNPs on outcome following AIS is unknown.
Methods: Patients were prospectively enrolled after onset of AIS. Clinical and demographic data were collected and neurological outcomes assessed at 3 months. Blood was drawn at multiple time points to quantify leukocyte subsets and assess plasma levels of C-reactive protein and a panel of cytokines. Genotyping for the TLR4 SNPs was also performed on blood samples. Uni- and multivariate analyses were performed to assess associations between TLR4 SNP haplotype and (i) each laboratory parameter noted above, (ii) infection risk and (iii) stroke outcome.
Results: Of the 42 patients included; 6 (14%) were heterozygous for either one or both TLR4 SNPs. Baseline characteristics were similar in patients with or without a TLR4 SNP. In analyses adjusted for both initial stroke severity and age, the presence of a TLR4 SNP was associated with increases in blood leukocytes, plasma C-reactive protein and the cytokine interleukin-1 receptor antagonist (IL-1ra). The presence of either TLR4 SNP was also associated with a trend toward increased rates of infection (adjusted odds ratio and 95% confidence interval of 8.20 and 0.826-81.5, respectively) and a decreased likelihood of favorable outcome as defined by a modified Rankin Scale score of two or less at three months from stroke onset (0.014, 0.00-0.759).
Conclusions: In AIS patients, functionally significant genetic variations in TLR4 influence both rates of stroke-associated infection and neurological outcome. These data suggest a direct connection between TLR4 function and stroke pathophysiology.
- © 2012 by American Heart Association, Inc.