Regional homogeneity in the patients of irritable bowel syndrome complicated with depression: a resting-state functional magnetic resonance imaging study

Abstract

Objective: To explore the changes of the brain regional homogeneity (ReHo) in the patients of irritable bowel syndrome (IBS) complicated with depression by using resting-state functional magnetic resonance imaging (rs-fMRI) and to investigate the relation between abnormal brain function and depression in those patients. Methods: A total of 35 patients with IBS were included in this study, collected in Gastroenterology Department of Affiliated Hospital of Hangzhou Normal University from June 2015 to June 2017.According to Hamilton's Depression Scale (HAMD)-17 score, the IBS patients was divided into two groups: IBS with depression group, 21 cases and non-depression group, 14 cases.Thirty-six healthy controls were recruited at the mean time (gender, age and years of education were matched with the patients). Rs-fMRI and 3D T1 data were acquired with 3.0 T scanners.For all subjects, ReHo, a method measuring the synchronism of regional spontaneous activities, was calculated and one-way ANOVA was performed to assess the group effects.For those regions with significant group effects, correlation between ReHo values and GSRS and HAMD scores was analyzed too. Results: Significant group effects were found in multiple regions: the right pons, the left inferior temporal gyrus (ITG)/fusiform, the left superior temporal gyrus (STG)/temporal pole, the right inferior frontal gyrus (IFG), the right middle occipital gyrus (MOG), the right caudate nucleus, the left posterior cingulate cortex/precuneus (pCC/pC), the left postcentral gyrus, the right inferior parietal lobule (IPF). Compared with control group, all the two patient groups had increased ReHo values in the left pCC/pC, the right IPF, the left postcentral gyrus and the left STG/temporal pole; all the two patient groups had decreased ReHo values in the right MOG and the right IFG.Compared with non-depression group, depression group had increased ReHo values in the right caudate nucleus, and decreased ReHo values in the right pons, the left pCC/pC, the right IPF, the left postcentral gyrus.Particularly, there was no significant difference in the ReHo value in the right caudate nucleus between the control group and the non-depressed IBS group.In the depression group, significantly positive correlations were observed between ReHo values and HAMD scores in the left pCC/pC (r=0.599, P=0.011), and significantly positive correlations were observed between ReHo values and GSRS in the left postcentral gyrus (r=0.547, P=0.023). Conclusions: IBS patients have abnormal ReHo regions in default network and pain regulation-associated brain area.IBS with depressed patients has its own characteristics in the brain regions which related with pain perception and self-regulation.IBS could has an abnormal self-regulation of visceral pain, which is associated with the occurrence of depression.Depression can aggravate the disorders of pain perception and other functions of IBS patients.