Diesel exhaust exposure induces angiogenesis

Area of Science:

• Cardiovascular Biology
• Environmental Health
• Toxicology

Background:

• Diesel exhaust particles (DEP) are a major air pollutant with known adverse health effects.
• The impact of whole diesel exhaust (WDE) on angiogenesis and vasculogenesis remains incompletely understood.
• Understanding these effects is crucial for assessing cardiovascular risks associated with air pollution.

Purpose of the Study:

• To investigate the hypothesis that WDE exposure enhances angiogenesis and vasculogenesis.
• To determine the molecular mechanisms underlying WDE-induced vascular changes.

Main Methods:

• Male apolipoprotein E-deficient mice underwent subcutaneous scaffold implantation or hindlimb ischemia.
• Mice were exposed to WDE (approx. 1mg/m(3) DEP) or filtered air for 6 hours/day, 5 days/week, for 2, 5, or 8 weeks.
• Vascularization was assessed using histology (CD31, alpha-SMA), micro-CT, and in vitro/ex vivo assays (endothelial cells, aortic rings); molecular analysis included VEGF, HIF-1alpha, and PHD2 mRNA expression.

Main Results:

• WDE exposure significantly increased cell counts, macrophage infiltration, and CD31 expression in scaffolds.
• Increased vessel volume was observed in both ischemic and non-ischemic hindlimbs post-WDE exposure.
• WDE induced capillary-like tube formation and sprouting, increased VEGF and HIF-1alpha mRNA, and decreased PHD2 expression.

Conclusions:

• WDE exposure demonstrably enhances angiogenesis and vasculogenesis in mice.
• The observed angiogenic effects are associated with increased inflammation and altered expression of key regulatory factors (HIF-1alpha, VEGF, PHD2).
• These findings highlight a potential mechanism by which air pollution may impact cardiovascular health.