Leukotrienes - What Are They?
Leukotrienes are substances involved in asthmatic, allergic and inflammatory reactions.
They are secreted by some types of white blood cells, hence the name "leuko"(white blood cells) +"trieni"(three conjugated double bonds between carbon atoms). Their distribution in the organism is almost ubiquitous.
Leukotyrenes are synthesized starting from arachidonic acid, thanks to the action of the 5-lipoxygenase enzyme.
Role in Asthma
Leukotrienes are released from leukocytes and other cells during allergic and inflammatory reactions.
The most evident and known action, typical of a subgroup of leukotrienes called cysteinilleukotrienes (LTC4, LTD4, LTE4), is to cause the constriction of the bronchioles located inside the lung tissue, in a manner 1,000 times more intense than that caused by "histamine.
In addition to this action, cysteinileukotrienes increase the production of mucus (phlegm), increase vascular permeability (edema) and have eosinophilotactic action (recall eosinophils).
Allergens, substances capable of triggering an allergic reaction or an asthmatic crisis in predisposed people, act by stimulating, among other things, the release of leukotrienes at the bronchial level. In response to the release of these and other spasmogens, the smooth and therefore involuntary muscles , the airway contracts, making it difficult to breathe.
Antileukotriene
Given their importance in the etiopathogenesis of asthma and allergies, pharmaceutical companies have long worked to discover drugs capable of inhibiting the synthesis of leukotrienes. The result of these efforts was the recent entry into therapy of antileukotrienics (Zafirlukast - Accoleit and Zafiist - Montelukast - Lukasm, Montegen, Singulair -).
These medicines do not prevent the synthesis of leukotrienes but block their interaction with the receptors present in the bronchial and lungs.
Leukotrienics are indicated in the prevention of exercise-induced (exercise-induced) asthma. They are less effective than inhaled corticosteroids (flunisolide, beclomethasone) and long-acting β2-adrenergic agonists (salmeterol) but, thanks to their reduced side effects, can be used in combination with them as support or second line drugs.
