Increased body weight is a chronic health problem which has
emanated from the globalized food market and dietary habit. This has led to the
different types of ailments which occur in obese individual simultaneously and
referred to as metabolic disorders. Metabolic syndrome includes conditions such
as obesity, insulin-resistance, diabetes, hypertension, cardiovascular, and
some forms of cancers. Lung dysfunction is also associated with increased body
weight in which obese persons feel difficulty in breathing and could develop
asthma like symptoms if not treated timely. Many studies have shown that such
patients are difficult to treat with the regular asthma medicines, which
suggests that probably breathing problem in obese people is caused by different
mechanism and is different than allergic asthma.
Elevated levels of cysteinyl
leukotrienes (CysLTs) in the urine of obese asthma patients indicate elevated
levels of biochemical pathway that forms this compound. CysLTs are responsible
for the inflammation and swelling and can change the cell’s behavior by
modifying their structure and function. In fact, LTs are known to cause lung
problems in asthma and COPD in non-obese people and inhibitors of LTs receptors
or of enzymes that make LTs are used as drug to treat such patients.
In the obese individual the fat deposits in the special
cells called adipocytes which grows in number and size upon energy rich diet
consumption. The adipocytes secret certain chemicals which attract macrophages,
the policing cells in body which fight with pathogens and infectious agents and
also some of the body’s own molecules and materials and removes them. In
excessive accumulation of adipocytes, more macrophages get attracted to adipose
tissue, get overactive and secrete molecules like cytokines, chemokines and
also CysLTs which are released in blood and can cause inflammation in other
body parts.
When it reaches to the lungs, CysLTs can activate the lung
cells which can also secret the inflammation causing molecules and attract
immune cells to the lungs. This scenario is similar to the early stage of
development of asthma. Over the period of time these molecules can change the
structure and function of lung cells including epithelial cells which can
change into either mucous cells of fibrous cells and lung function may get
severely affected. Mucous cells secret large amount of mucous which inhibit the
gas exchange in the lung while fibrous cells affect the elasticity of the lung
and lung cannot expand upon breathing.
How obesity causes these changes in the lungs is still not
known and scientists are actively working to find answers. The mechanism once
clear can help in treating such patients using the appropriate drugs.
Reference: Yadav UC,
Srivastava SK. Cysteinyl Leukotrienes (CysLTs): Role in Obesity-Induced Asthma.
Curr Mol Med. 2015; 15(7): 598-605.
