[Mechanisms of action of nebulized low molecular weights heparin in patients with bronchial asthma]

Bronchial asthma is a chronic disease of the respiratory tract. Search for alternative to presently used therapies seems to be the way to obtain a better control of asthma. Heparin is an acidic mucopolysaccharide and in the past years there has been a number of reports on the role of heparin and low-molecular-weight heparin (LMWH) in chronic inflammatory disorders of the respiratory tract. Our aim was to estimate the effect of long-time LMWH nebulization on selected parameters in asthmatic patients. Twenty-four patients entered the study. All of them were subjected to bronchoscopy with BAL, in 8 patients this procedure was performed twice: before and after heparin treatment. After 14 days of treatment we observed an increase in FEV1 (from 73.93 +/- 14.14% (in % of nominal value) to 89.62 +/- 10.08% (p = 0.0049). Additionally we noted a decrease in the percentage of eosinophils and lymphocytes in BAL sediments, from 4.86 +/- 3.48% to 1.25 +/- 2.76%; p = 0.0006 and from 5.39 +/- 2.25% to 2.94 +/- 1.23%; p = 0.0209, respectively. This changes were paralleled by a drop of EG2 in BAL supernatant from 1.00 +/- 0.99 to 0.13 +/- 0.35, p = 0.0256. In blood serum level of histamine 0.74 +/- 0.77 to 0.1 +/- 0.22; p = 0.0493. We did not observe significant changes in IL-5, sVCAM-1 or ECP concentrations in serum. Also different LMWH dosing (5-10 kUIC anti-Xa b.i.d.) did not produce any dose-response effect. We conclude, that LMWH in nebulization can be a valuable add-on treatment in bronchial asthma, and its most likely mechanisms of action are: prevention of mast cell degranulation (histamine decrease), decreased eosinophil activation (lower EG2), and modification of inflammatory cells influx (decreased percentages of eosinophils and lymphocytes in BAL).