Severe Asthma's Effects May Extend Beyond the Lungs, Brain Imaging Study Suggests

Individuals with severe asthma show subtle differences in brain structure compared with individuals whose asthma is well controlled, according to research findings presented at the European Respiratory Society (ERS) Congress in Barcelona, Spain. Data from the study, led by researchers from the National Institute for Health and Care Research (NIHR) Biomedical Research Centre in Bristol and City St George’s, University of London, suggest that the inflammation behind severe asthma may extend beyond the lungs.¹

“Asthma is usually thought of as a lung disease, but [individuals] with asthma often report problems with mood, memory, and concentration,” said George Nava, PhD, MBBS, an NIHR academic clinical lecturer in respiratory medicine at the University of Bristol.²

Severe Type 2 Asthma Carries a Heavy Burden

Severe type 2 asthma results from an overactive immune response. It causes persistent inflammation, frequent attacks, and breathing difficulties. Many patients need multiple medications, and some remain difficult to treat even with intensive therapy. According to Apostolos Bossios, MD, PhD, head of the ERS Assembly 5 on airway diseases, asthma, chronic obstructive pulmonary disease, and chronic cough, type 2 is the most common asthma phenotype, and roughly 5% to 10% of patients progress to severe disease despite high-intensity treatment.¹

Study Design and Population

The researchers presented the abstract as baseline structural brain imaging data from biologic-naive patients with type 2–high severe asthma in the CONTENTed study (ISRCTN74240789). They enrolled 50 patients with severe type 2 asthma and compared them with 25 people with well-controlled mild or moderate type 2 asthma. All participants underwent MRI using quasi-diffusion imaging, a technique that can show the microscopic structure of white matter pathways in the brain.^1,2

The severe asthma group had a median fractional exhaled nitric oxide (FeNO) of about 56 ppb, a median blood eosinophil count of 490 cells/μL, and a median forced expiratory volume in 1 second of 80.7% predicted. In the mild-to-moderate group, the median FeNO was 14 ppb.²

White Matter and Regional Volume Differences

Patients with severe asthma had less-organized white matter than those with well-controlled asthma. The investigators also found differences in the size of structures, such as the hippocampus, and regions, such as the temporal lobes. Compared with the mild-to-moderate group, the severe asthma group had significantly lower cerebral white matter volume and lower volumes in the left and right temporal lobes and the left frontal lobe.^1,2

Across all participants, higher levels of type 2 inflammation were associated with greater white matter differences. Nava cautioned that the study cannot prove that inflammation causes these changes; however, he said the findings point to “a biological link that deserves further investigation.”^1,2

The team is now studying whether these differences change after patients start treatments that target the inflammation driving severe type 2 asthma. James Dodd, PhD, MBChB, MRCP, professor of respiratory medicine at the University of Bristol and chief investigator for the study, said a central question is whether the brain changes can be prevented or reversed.^1,2

Findings Build on Prior Neuroimaging Evidence

The results add to earlier work linking asthma severity to brain health. In a 2022 study, investigators obtained diffusion-weighted MRI data from 111 individuals with asthma (ranging from mild to severe) and 135 healthy controls. Participants with asthma had widespread, large-magnitude differences in imaging metrics that were consistent with neuroinflammation and neurodegeneration. These differences were strongly associated with the glial activation marker GFAP. Greater asthma severity was tied to worse imaging outcomes, which in turn were associated with slower processing speed.³

Those study authors called for research into whether treatments targeting these features of asthma could reduce their effects. The ongoing CONTENTed follow-up is designed to address that question.^1,3

Implications for Pharmacy Practice

Together, these presentations point to a broader view of severe asthma: Persistent type 2 inflammation may affect more than the lungs, and ongoing monitoring may help detect worsening of control earlier on. For pharmacists who counsel patients on biologic therapy and controller adherence, the CONTENTed follow-up data will be worth watching.¹

REFERENCES

1. Severe asthma linked to changes in brain structure. News release. European Respiratory Society. September 8, 2026. Accessed September 23, 2026. https://www.eurekalert.org/news-releases/1142443

2. Gawel R. Decreases in brain volume associated with severe asthma. Healio. September 16, 2026. Accessed September 23, 2026. https://www.healio.com/news/neurology/20260916/decreases-in-brain-volume-associated-with-severe-asthma

3. Rosenkranz MA, Dean DC 3rd, Bendlin BB, et al. Neuroimaging and biomarker evidence of neurodegeneration in asthma. J Allergy Clin Immunol. 2022;149(2):589-598.e6. doi:10.1016/j.jaci.2021.09.010