Serial measurement of vascular endothelial growth factor and transforming growth factor-β1 in serum of patients with acute ischemic stroke

Abstract

Background and Purpose - Both vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) are expressed in higher than normal concentrations in the penumbra of patients after ischemic stroke. Because both cytokines are central to the processes of angiogenesis, tissue inflammation, and fibrosis, we performed serial measurements of these cytokines in patients with cerebral infarction and determined their relationship to stroke etiology and volume. Methods - We serially (at days 0, 1, 3, 7, and 14) measured the serum levels of VEGF and active TGF-β1 in 29 patients with acute ischemic stroke. Age - matched healthy subjects (n=26) were used as controls. Results - Expression of VEGF was significantly increased in the majority of patients after acute stroke at each of the time points compared with normal controls. Highest expression occurred at day 7 (588±121 pg/mL; P=0.005), and it remained significantly elevated at 14 days after stroke. Expression of VEGF correlated with infarct volume, clinical disability (Scandinavian Stroke Scale), and peripheral leukocytosis and was significantly higher in patients with atherothrombotic large-vessel disease and ischemic heart disease (P<0.05 in all cases). In contrast, expression of active TGF-β1 was not significantly different from control patients at any of the measured time points. When the mean concentration of TGF-β1 from each patient (pooled time points) was compared with the control mean, a significant increase was found in only 2 patients, whereas levels decreased in 12 patients (P<0.05). There was no correlation between circulating active TGF-β1 and VEGF expression, leukocytosis, stroke subtype, or patient disability as assessed by Scandinavian Stroke Scale score. Conclusions - VEGF but not TGF-β1 showed a dramatic increase in serum of stroke patients. Correlation between stroke severity and VEGF concentration suggests it could be involved in the subsequent repair processes resulting in partial recovery after stroke. Correlation between VEGF expression and peripheral leukocytosis suggests that these changes may also reflect the immunologic status of the patient. VEGF may play an important role in the pathophysiology of acute ischemic stroke and could be of value in future treatment strategies.