Leukotriene B4

Leukotriene B4 (LTB4) is a downstream product of arachidonic acid in eicosanoid biosynthetic pathways (Pediatr Pulmonol. (2013)). It is very import compound which can be linked to more than 10 diseases and can be detected by many methods including Enzyme Immunoassay (EIA), GC-MS and LC-MS/MS. Description of disease(s) related to Leukotriene B4 (LTB4):

Asthma

GC-MS can be used to accurately quantify and measured EBC of leukotrienes in asthmatic adults and children. Higher concentrations of leukotriene B4 in EBC of asthmatic patients in comparison with healthy control subjects increase asthma severity in adults. LTB4 concentrations were also increased in asthmatic children compared to healthy subjects, with differences detected for 2 degrees of asthma severity. The direct effects of LTB4 on human airway smooth muscle (ASM) have also been studied and suggested a role for a LTB4-BLT1 signaling in ASM responses contributing to the pathogenesis of airway remodeling in asthma. LTB4 concentrations in EBC were also increased in COPD patients and asthmatic patients compared to healthy controls. The difference might be contributed from the presence of reversibility in airway obstruction, and be part of a inflammatory process.

Pulmonary Disease, Chronic Obstructive

The LTB4 was detected in nasal lavage, sputum and BAL fluid in patients with stable COPD. The concentration of LTB4 in sputum and BAL also associated with other biomarkers of inflammation such as myeloperoxidase and elastase activity. The patients with acute exacerbations of COPD were found to have significantly increased level of LTB4 but the concentration of LTB4 will decrease during treatment although they remain in higher levels in COPD patients than healthy controls. An increased neutrophil chemotactic activity to which LTB4 contributes were also studied in EBC from COPD patients. The reciprocal interactions between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVD) were studied. EBC concentrations of LTB4, and serum levels of LTB4 were all significantly higher in patients with COPD than in healthy subjects while COPD patients with CVD were not found to have higher concentrations of LTB4.

Cystic Fibrosis

Chronic neutrophilic airway inflammation is a key symptom of cystic fibrosis (CF). Noninvasive inflammatory markers may be useful in monitoring CF. Leukotriene B4 (LTB4) is a noninvasive inflammatory biomarker that may be elevated in EBC levels of CF patients during exacerbation.

Sarcoidosis

The differences in levels of CysLT, LTB4, and 8-isoprostane in EBC of patients with sarcoidosis and healthy controls were analyzed. A positive correlations between BALF and EBC eicosanoids has been found.

Asthma, Aspirin-Induced

A significant increase in patients with aspirin-Induced asthma in 5-HETE, 12-HETE, and 15-HETE levels of EBC was associated by an increase in level of LTC4, LTD4, and LTE4, but not in LTB4.

Carcinoma, Non-Small-Cell Lung

LTB4 can be recognized in EBC collected from lung cancer, and their concentrations found to be significantly lower than those in BALf patients using diagnosed NSCLC. The EBC level of LTB4 and cys-LTs in lung cancer patients was higher than those measured in healthy, age-matched smokers and healthy nonsmokers.

Community-Acquired Infections, Pneumonia

LTB is a strong EBC biomarkers for community acquired pneumonia (CAP). The EBC of LTB4 increased in CAP and return to normal after 1 week when 18 children with CAP and 17 healthy children were recruited. EBC collection is a feasible way to monitor in children with CAP.

Dermatitis, Atopic

pH, LTB4 and 8-isoprostane in EBC are sensitive markers of airway inflammation in children with AD. These EBC could be used to predict the development of asthma later in life in children with AD.

Lung Neoplasms

Compared with both healthy subjects, patients with lung cancer achieved higher concentrations of cys-LTs (p< 0.05) and LTB4 (p < 0.05) in EBC. The levels of cys-LT, LTB4 and 8-isoprostane in EBC from lung cancer patients showed their concentrations in BALf. They can be used to monitor the disease and to assess the effectiveness of therapy.

Pneumoconiosis

The possible impact on extra-pulmonary disorders in EBC markers was analyzed. Both level of LTB4 and cysteinyl LTs were increase in asbestos-exposed subjects (p<0.05).

Respiratory Sounds

21 healthy nonatopic children and 25 patients with wheezing episodes were recruited for analyzing their EBC profiling. LTB4 concentrations were found to be higher in children with wheezing episodes than in healthy controls.

Rhinitis

EBC of LTB4 and LTE4 achieved higher concentrations in seasonal allergic rhinitis patients than in healthy subjects and reduced the concentrations after the pollen season as compared with levels in season.

Rhinitis, Allergic, Seasonal

The seasonal and postseasonal elevated in both EBC of LTB4 and LTE4 concentrations for the patients with seasonal allergic rhinitis significantly associated with the later increase in bronchial responsiveness to methacholine (BRM). The relationship can be used to monitor early inflammatory processes in the lower airways of patients with allergic rhinitis.

Sleep Apnea Syndromes

Obstructive sleep apnea (OSA) syndrome is an upper airway inflammation recognized in adults. LTB4 concentrations of EBC significant increased in children compared to control subjects.

Summary of extracted biomedical information

Leukotriene b4 is associated with abnormalities such as Asthma, Lung diseases, Inflammatory disorder, Septicemia and Atopic. The involved biomedical functions are known as Inflammation, Exhalation, inhibitors, Synthesis and amylase activity. The associated genes/proteins with Leukotriene B4 are CCL2 gene, LTB4R gene, interleukin-12 subunit p40, MAPK3 gene and TLR4 gene. Leukotriene b4 is associated with lipid mediator, Hydrocarbons, hydroxyl group, carboxylate and Anions.