Differential Brain Structural and Functional Patterns in Crohn's Disease Patients are Associated with Different Disease Stages

Lay Summary We found morphological and functional brain changes associated with different stages of disease activity in Crohn's disease. These findings may represent the neural correlates of fatigue, irritable bowel syndrome-like symptoms, and cognitive-emotional impairments; these could be useful for evaluating disease progression. Background Crohn's disease (CD) is an inflammatory, chronic disorder that alternates between a quiescent phase and inflammatory flare-ups. Research has begun to elucidate the impact of CD in modulating brain structure and function. The previous neuroimaging studies mainly involved CD patients in remission (CD-R); therefore, little is known about how inflammation influences brain-related features in different stages of the disease. We carried out a magnetic resonance imaging (MRI) study to explore whether the different levels of disease activity may differentially affect brain structure and function. Methods Fourteen CD-R patients, 19 patients with mild to moderate inflammatory activity (CD-A), and 18 healthy controls (HCs) underwent an MRI scan including structural and functional sequences. Results Between-group comparisons showed morphological and functional brain differences distinctively associated with the stage of disease activity. The CD-A patients had reduced gray matter within the posterior cingulate cortex (PCC) relative to CD-R patients. Analysis on resting fMRI data showed the following patterns: (1) increased connectivity within the left fronto-parietal network (in the superior parietal lobe) in CD-R patients relative to CD-A patients; (2) decreased connectivity in the motor network (in parietal and motor areas) in the CD-A group relative to the HC group; (3) reduced connectivity in the motor network and (4) in the language network (in parietal areas and in the PCC) in CD-R patients relative to HC. Conclusions The present findings represent a further step towards understanding brain morphological and functional changes in the active vs remission stages of CD patients.