Pain. 2022 May 25. doi: 10.1097/j.pain.0000000000002699. Online ahead of print.

Jennifer S Labus ^1 2 3 4, Chencai Wang ⁴, Emeran A Mayer ^1 2 3 4, Arpana Gupta ^1 2 3 4, Talia Oughourlian ⁴, Lisa Kilpatrick ^1 2 3 4, Kirsten Tillisch ^1 2 3 4, Lin Chang ^1 2 3 4, Bruce Naliboff ^1 2 3 4, Benjamin M Ellingson ^1 3 4

Author information

¹Oppenheimer Center for the Neurobiology of Stress and Resilience, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.

²Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.

³Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.

⁴Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.

Abstract

Preliminary evidence suggests that there are sex differences in microstructural brain organization among individuals with irritable bowel syndrome (IBS). The aim of this study was to further investigate sex-dependent differences in brain microstructure and organization in a large sample of well-phenotyped participants with IBS compared to healthy controls (HC). We hypothesized that female IBS patients would show evidence for increased axonal strength and myelination within and between brain regions concerned with pain and sensory processing, when compared to males with IBS. We also hypothesized that female compared to male IBS subjects show greater levels of somatic awareness and sensory sensitivity consistent with multisystem sensory sensitivity.Diffusion tensor images (DTI) and clinical assessments were obtained in 100 HC (61 Female) and 152 IBS (107 females) on a 3T Siemens Trio. Whole brain voxel-wise differences in fractional anisotropy (FA), mean (MD), radial (RD) and axial diffusivity (AD), and track density (TD) as differences in somatic awareness and sensory sensitivity were assessed using the general linear model.Female compared to male IBS participants showed extensive microstructural alterations in sensorimotor, corticothalamic, and basal ganglia circuits involved in pain processing and integration of sensorimotor information. Together with the observed increases in symptom severity, somatic awareness, and sensory sensitivity the findings support the hypotheses that the etiology and maintenance of symptoms in females with IBS may be driven by greater central sensitivity for multiple sensory stimuli.