Lower amounts of sphingolipids in nasal fluid may indicate childhood asthma

Key takeaways:

• Previous research has linked sphingolipids with asthma.
• Patients with asthma had lower levels of sphingolipids in nasal fluid than controls.
• Nasal fluid collection is less invasive than blood testing.

WASHINGTON — Airway sphingolipids were detected in small volumes of nasal fluid taken from children with asthma, according to a presentation at the American Thoracic Society International Conference.

Nasal fluids therefore may be useful in assessing a sphingolipid endotype of asthma, Zenna Solomon, MD, a second-year pulmonology fellow in the department of pediatrics at Weill Cornell Medicine, told Healio.

“We looked at nasal fluid sphingolipids as a biomarker for asthma in children. Previous research has linked sphingolipids to asthma,” Solomon said.

Prior genotype association studies have linked chromosome 17q21 with childhood asthma, Solomon explained, adding that this locus includes genes that express ORMDL3, which is a key regulator in sphingolipid synthesis.

“Despite all this, there’s limited data on sphingolipid composition in the respiratory tract of children,” she said.

The researchers then set out to investigate whether there were asthma-associated variations in sphingolipids in the upper respiratory tracts of children and to determine the relationship between sphingolipids in the nasal fluid and in the blood.

The study enrolled 293 children including 150 with persistent asthma and 143 controls aged 2 to 18 years in three boroughs of New York City. The researchers genotyped these children for the 17q21 single nucleotide polymorphism rs7216389, or the asthma risk allele.

Using the Wilcoxon Rank-Sum Test, the researchers compared the genotypes of the patients with persistent asthma with those of the controls.

“Our patients with asthma had higher rates of the asthma risk allele, which is the T allele, which we were happy to see,” Solomon said.

Also, the researchers collected approximately 20 µL of nasal fluid from each patient.

“We have a microsampling device that we hold in the patient’s nose, because they’re children, for about a minute,” Solomon said. “It’s relatively noninvasive, especially comparing it to blood.”

The researchers then analyzed 32 sphingolipids in these samples as well as in blood plasma and cell samples from the patients via high-performance liquid chromatography-tandem mass spectrometry.

The patients with asthma had lower amounts of sphingolipids in their nasal fluid (dihydroceramide C16, dihydroceramide C18, ceramide C18, ceramide C20, ceramide C22) and blood cells (dihydroceramide C24, dihydroceramide C24:1, ceramide C24:1) and higher amounts in their blood plasma (sphinganine-1-phosphate, ceramide C24, sphingosine-1-phosphate, sphingomyelins C24:1).

“This was consistent with prior work that we did looking at blood sphingolipids, but it was interesting to see that we were able to project these sphingolipids in the nasal fluids and that these findings paralleled what we saw in the blood cells,” Solomon said.

Solomon and her colleagues concluded that nasal fluid may be useful in assessing a sphingolipid endotype of asthma.

“This a potential tool that we can use,” she said. “Further studies need to be done to figure out how we can link this to different asthma endotypes.”

The researchers have additional demographic and allergy data from the patients in this cohort.

“We want to do further analysis to see if there are different trends that we can see in other subsets of patients,” Solomon said. “That’s our next step.”