s-adenosylhomocysteine and Asthma

Phosphatidyl ethanolamine methylase (PEMT) is an enzyme involved in the methylation of membrane phospholipids which plays a very important role in the modulation of the activity of the beta-receptors and the production of phosphatidylcholine, substrate of phospholipase A2. This report describes a study of PEMT on the membranes of blood leucocytes and alveolar macrophages obtained by bronchoalveolar washings in different types of asthma: allergic, intrinsic and occupational. This was accompanied by parallel study of respiratory function tests and the level of bronchial reactivity to carbachol in asthma sufferers as well as other alveolar biological parameters: phospholipid fractions of surfactant, angiotensin conversion enzyme and protein/albumin ratio. The authors found a significant increase (in comparison with controls) in PEMT activity both in macrophages and leucocytes in cases of intrinsic asthma. However, there was no correlation between the level of activity of the enzyme and the degree of bronchial hyper-reactivity. There was no change in alveolar phospholipid environment. In the light of these findings, the role of membrane activation of the alveolar macrophage is discussed in the physiopathology of intrinsic asthma.

Topics: Adult; Aged; Asthma; Cell Membrane; Female; Humans; Kinetics; Leukocytes; Macrophages; Male; Methylation; Methyltransferases; Middle Aged; Phosphatidylethanolamine N-Methyltransferase; Phospholipids; Pulmonary Alveoli; S-Adenosylhomocysteine