2010 Review: Role of leukotrienes in asthma

Leukotrienes are lipid mediators involved in the pathogenesis of asthma:

- Cysteinyl leukotrienes are important in airway remodeling

- Leukotriene B4 has an important role in the development of asthma (sensitization)

Leukotrienes are key mediators of exercise-induced bronchoconstriction and leukotriene modifiers reduce the severity of exercise-induced bronchoconstriction during short-term and long-term use.

Genetic variation in the leukotriene synthetic pathway affects the clinical response to leukotriene modifiers.


Eicosanoids are signaling molecules made by oxygenation of 20-carbon essential fatty acids. There are 4 families of eicosanoids (PP-LT): prostaglandins (PG), prostacyclins (PGI), leukotrienes (LT) and thromboxanes (TX).


Mast cell mediators including (PP-LT): prostaglandins (PG), prostacyclins (PGI), leukotrienes (LT) and thromboxanes (TX). See more Allergy and Immunology mind maps here.

What is the most potent bronchoconstrictor?

(A) LTB4

(B) LTC4

(C) acetylcholine

(D) histamine

(E) thromboxane A2 (TXA2)

(F) methacholine

Answer: B

CysLTs are the most potent bronchoconstrictor agents yet discovered, about 100-1000 times more potent than histamine. The second most potent bronchoconstrictor is thromboxane A2 (TXA2).

Cysteinyl‐LTs and LTB4 are, respectively, the most potent bronchoconstrictor agents and one of the most effective leukocyte chemotaxins yet.

References:
An update on the role of leukotrienes in asthma. Hallstrand, Teal, Henderson, William. Current Opinion in Allergy & Clinical Immunology. 10(1):60-66, February 2010.
Image source: Montelukast, from Wikipedia, the free encyclopedia, public domain.