The effect of inhaled heparin and related glycosaminoglycans on allergen-induced eosinophil infiltration in guinea-pigs

Aerosolized unfractionated heparin GM1060 significantly inhibited allergen-induced eosinophil infiltration into the airways of guinea-pigs (as assessed both histologically and by bronchoalveolar lavage, or BAL) at doses of 160 and 1600 U/ml. Similarly aerosolized unfractionated heparin, Multiparin was effective at reducing eosinophil levels in the BAL fluid at 1000, 2000 and 5000 U/ml, but this reduction was statistically significant only at the highest dose used. Additionally, Fragmin (a low molecular weight heparin) significantly inhibited allergen-induced eosinophil infiltration into BAL fluid at a dose of 500 U/ml, an effect that was lost at the higher doses of 1000 and 2000 U/ml. Allergen-induced eosinophil infiltration was unaffected by dermatan sulphate. However, the glycosaminoglycans chondroitin sulphate A, chondroitin sulphate C and heparan sulphate were able to influence the extent of allergen-induced eosinophil infiltration into BAL fluid. These results suggest that heparin and some related glycosaminoglycans can inhibit allergen-induced eosinophil infiltration when administered directly to the airways.