Systemic and vascular inflammation in experimental allergic asthma

Allergic asthma and atherosclerosis are inflammatory diseases characterized by similar sets of circulating inflammatory cells, in addition to mast cells in the airway and vessel wall. Animal models and human studies provide evidence of a potential interaction between the two apparently unrelated diseases. The main objective of this study was to determine whether experimental allergic asthma is accompanied by inflammatory responses, measured as the activation of the vasculature and the presence of immune cells in the perivascular adipose tissue. For this purpose, male Dunkin Hartley guinea pigs weighing 250 - 300 g were sensitized twice with 10 μg ovalbumin dissolved in aluminium hydroxide (Al(OH)₃). Allergen inhalation was performed 10 days after the second immunization and continued 5 days a week for 2 months. After that period, T cell and macrophage content was measured by flow cytometry. The aortic expression of inflammatory markers was studied by real-time PCR. The number of T cells in the peripheral blood was significantly greater in the allergic group in comparison to the sham group. We did not find any significant differences in the leukocyte content of the perivascular adipose tissue between the groups. Nor did we identify significant changes in the expression of inflammatory markers (tumor necrosis factor, monocyte chemoattractant protein-1) and adhesion molecules (intercellular adhesion molecules and vascular cell adhesion molecules) in the aorta. Interestingly, we observed a significantly decreased expression of the endothelial nitric oxide synthase (eNOS) mRNA in the aortic vessel of the allergic group compared to the sham group.