Serum microRNA (miRNA) may differentially contribute to asthma pathogenesis in older (> 65 years old) vs younger (30 to 50 years old) patients, according to a study published in Respiratory Research.
The course of asthma may differ between older vs younger asthmatics, partially due to an age-dependent abnormal immune response. miRNAs are involved in the control of several physiological processes, including aging, and dysregulation of miRNAs has also been implicated in the pathophysiology of bronchial asthma.
Thus, researchers aimed to determine the influence of serum miRNA expression on asthma characteristics and systemic inflammation markers in older vs younger asthmatics. Control and severity of asthma, pulmonary function, and FeNO were assessed in 28 older and 31 younger asthmatic patients; a control group included 59 healthy individuals, both older and younger.
The researchers found no difference in serum miRNA expression between asthmatics and healthy controls. Older asthmatics demonstrated lower expression of miRNA-106a and miRNA-126a than younger asthmatics (P=.003 and P=.02), and older controls had lower expression of miRNA-146a, -126a, -106a, and 19b than younger controls (P=.001, P=.003, P=.005, and P<.001, respectively).
Only younger asthmatics demonstrated a relationship between the expression of selected miRNAs and the level of asthma control and with airway inflammation. All patients with asthma demonstrated elevated tumor necrosis factor (TNF)α, interleukin-6, and sTNF-RI levels compared with controls (P=.026, P=.03, and P<.001, respectively). Older asthmatics demonstrated a higher TNFα level than older controls (P<.001), and older asthmatics had a higher level of sTNF-RI than younger asthmatics (P<.001). A significant correlation was observed between serum levels of proinflammatory cytokines and selected miRNAs.
“To conclude, an association between miRNA expression and age was observed in both the control group and in asthma patients,” stated the study authors. They added, “Circulating miRNA expression was associated with selected features of asthma only in younger patients.”
Wardzyńska A, Pawełczyk M, Rywaniak J, Makowska J, Jamroz‐Brzeska J, Kowalski ML. Circulating miRNA expression in asthmatics is age-related and associated with clinical asthma parameters, respiratory function and systemic inflammation. Respir Res. 2021;22:177. doi:10.1186/s12931-021-01769-x