Networks Are Associated With Acupuncture Treatment in Patients With Diarrhea-Predominant Irritable Bowel Syndrome: A Resting-State Imaging Study

Abstract

Background: Irritable Bowel Syndrome (IBS), as a functional gastrointestinal disorder, is characterized by abdominal pain and distension. Recent studies have shown that acupuncture treatment improves symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D) by altering networks in certain brain regions. However, few studies have used resting-state functional magnetic resonance imaging (fMRI) to compare altered resting-state inter-network functional connectivity in IBS-D patients before and after acupuncture treatment. Objective: To analyze altered resting-state inter-network functional connectivity in IBS-D patients before and after acupuncture treatment. Methods: A total of 74 patients with IBS-D and 31 healthy controls (HCs) were recruited for this study. fMRI examination was performed in patients with IBS-D before and after acupuncture treatment, but only at baseline in HCs. Data on the left frontoparietal network (LFPN), default mode network (DMN), salience network (SN), ventral attention network (VAN), auditory network (AN), visual network (VN), sensorimotor network (SMN), dorsal attention network (DAN), and right frontoparietal network (RFPN) were subjected to independent component analysis (ICA). The functional connectivity values of inter-network were explored. Results: Acupuncture decreased irritable bowel syndrome symptom severity score (IBS-SSS) and Hamilton Anxiety Scale (HAMA). It also ameliorated symptoms related to IBS-D. Notably, functional connectivity between AN and VAN, SMN and DMN, RFPN and VAN in IBS-D patients after acupuncture treatment was different from that in HCs. Furthermore, there were differences in functional connectivity between DMN and DAN, DAN and LFPN, DMN and VAN before and after acupuncture treatment. The inter-network changes in DMN-VAN were positively correlated with changes in HAMA, life influence degree, and IBS-SSS in IBS-D. Conclusion: Altered inter-network functional connectivity is involved in several important hubs in large-scale networks. These networks are altered by acupuncture stimulation in patients with IBS-D.

Keywords: acupuncture; fMRI; functional connectivity; independent component analysis; irritable bowel syndrome; mechanism.

FIGURE 1

Nine independent components in spatial maps. LFPN, left frontoparietal Network; DMN, anterior default mode network; SN, salience network; VAN, ventral attention network; AN, auditory network; VN, visual network; SMN, sensorimotor network; DAN, dorsal attention network; RFPN, right frontoparietal network; L, left; R, right.

FIGURE 2

Averaged functional networks activity. (A) Averaged functional networks of all subjects (between IBS-D before acupuncture and HCs); (B) Averaged functional networks of HCs; (C) Averaged functional networks of IBS-D patients before acupuncture; (D) Averaged functional networks of IBS-D patients after acupuncture; (1) anterior default mode network (DMN); (2) auditory network (AN); (3) left frontoparietal Network (LFPN); (4) right frontoparietal network (RFPN); (5) dorsal attention network (DAN); (6) sensorimotor network (SMN); (7) visual network (VN); (8) ventral attention network (VAN); (9) salience network (SN).

FIGURE 3

Procedures and data used for the study.

FIGURE 4

Connectivity comparisons of large-scale network between the IBS-D patients with HCs. (A) Connectivity matrix of functional network connectivity of large-scale network in IBS-D patients after acupuncture and HCs. (B) Connectivity of functional network connectivity of large-scale network in IBS-D patients after acupuncture and HCs; Hot colors represent positive functional network connectivity, and cool colors represent negative functional connectivity. LFPN, left frontoparietal Network; DMN, anterior default mode network; SN, salience network; VAN, ventral attention network; AN, auditory network; VN, visual network; SMN, sensorimotor network; DAN, dorsal attention network; RFPN, right frontoparietal network; L, left; R, right.

FIGURE 5

Connectivity comparisons of large-scale network between the IBS-D patients before and after acupuncture. (A) Connectivity matrix of functional network connectivity of large-scale network in IBS-D before and after acupuncture. (B) The changes of functional network connectivity of large-scale network in IBS-D before and after acupuncture. (C) Connectivity of functional network connectivity of large-scale network in IBS-D patients before and after acupuncture; Hot colors represent positive functional connectivity, and cool colors represent negative functional connectivity. LFPN, left frontoparietal Network; DMN, anterior default mode network; SN, salience network; VAN, ventral attention network; AN, auditory network; VN, visual network; SMN, sensorimotor network; DAN, dorsal attention network; RFPN, right frontoparietal network; L, left; R, right.

FIGURE 6

Correlation between altered FC and clinical outcomes in patients with IBS. (A) The alteration of DMN-VAN was positively correlated with the changes in HAMA (P = 0.024, r = 0.35); (B) The alteration of DMN-VAN was positively correlated with the changes in life influence degree (P = 0.022, r = 0.32); (C) The alteration of DMN-VAN was were positively correlated with the changes in IBS-SSS (P = 0.05, r = 0.30).