VEGF-A levels predict outcome in ventilator-associated pneumonia
Elevated levels of circulating vascular endothelial growth factor (VEGF)‐A are associated with early resolution of ventilator-associated pneumonia (VAP), regardless of disease severity, a study has found.
Researchers measured serum VEGF‐A levels for 7 consecutive days in 82 VAP patients. They also obtained bronchoalveolar lavage (BAL) samples from experimental mouse challenged intratracheally with Pseudomonas aeruginosa at the following time points: 24, 48 and 124 hours after bacterial challenge. Levels of VEGF‐A, tumour necrosis factor alpha (TNF‐α), interleukin (IL)‐1β, interferon‐gamma (IFNγ) and myeloperoxidase (MPO) activity were measured in the animal samples.
VEGF-A levels increased significantly on day 5. The increase was <45 percent in 36 patients and ≥45 percent in 46. Specifically, in the group of patients showing greater increase in VEGF-A levels, VAP resolution occurred with greater frequency (65.2 percent vs 36.1 percent; p=0.014) and earlier (p=0.005). These results were not pathogen-specific.
On logistic regression analysis, the likelihood of VAP resolution was threefold higher in patients with a more than 45-percent increase in VEGF-A levels on day 5 (odds ratio, 3.32; 95 percent CI, 1.33–8.25).
VEGF‐A levels in mouse BAL and lung tissue increased significantly at 124 hours. In mice pretreated with bevacizumab, VEGF‐A concentrations decreased whereas TNF‐α and MPO markedly increased.
The present data indicate that an early increase in circulating VEGF-A in patients with VAP is associated with a greater chance of a clinical resolution of disease, whereas animal experiments in mice show that levels of VEGF-A rise in parallel with the resolution of inflammation after bacterial infection. Additional clinical and mechanistic studies are needed to establish the role of VEGF-A in VAP resolution, researchers said.