Relationship among sympathetic nerve activity at 2 min before defecation, symptoms, and quality of life.

Sympathetic nerve activity was evaluated by the sum of Δlow frequency/high frequency (LF/HF). (a) Intensity of abdominal pain, (b) satisfaction levels of defecation, (c) gastrointestinal symptom rating scale (GSRS) diarrhea score, (d) GSRS constipation score, (e) the Japanese version of the 8-item Short-Form Health Survey (SF-8) role physical, and (f) the SF-8 role emotional score were significantly correlated with the sum of ΔLF/HF at 2 min before defecation. Data were analyzed by Spearman test.</p

Autonomic nervous activities before and after defecation.

(a, b) Changes in sympathetic nerve activities before and after defecation were evaluated by the sum of Δlow frequency/high frequency (LF/HF) and the sum of LF/HF, respectively. (c, d) Changes in parasympathetic nerve activities before and after defecation were evaluated by the sum of ΔHF and the sum of HF, respectively. Data represents the median. Statistical significance was calculated by Mann–Whitney test (*p < 0.05).</p

Background characteristics.

Background characteristics.</p

T-shirt-type wearable device and smartphone application software.

Heart rate variability (HRV) was measured using a T-shirt wearable device attached to a transmitter in front of the T-shirt. The HRV data were transferred and recorded on a smartphone using Bluetooth. At the same time, life events, such as abdominal symptoms, defecation, eating, and awakening or sleep, were recorded in real time using a smartphone application software during HRV recording.</p

Autonomic nervous system activity in healthy controls and patients with IBS.

Autonomic nervous system activity in healthy controls and patients with IBS.</p

The graph of obtained data and measuring method of ANS activity.

(a) The real graph of obtained data about autonomic nervous system (ANS) activity and life events. The results of low frequency (LF) (yellow line) and high frequency (HF) (green line) represented in a graph. Life events, such as defecation and eating (the enclosed area with orange line) and period with positive symptoms (the enclosed area with pink line), were recorded. (b) Measuring method of ANS activity. The baseline LF/HF was defined as the value included in the range of the mean ± 2 standard deviations (dashed line) of LF/HF measured in the period with no symptoms. The sum of LF/HF was the area under the curve of LF/HF measured in the period with positive symptoms (upward diagonal). The sum of ΔLF/HF was the sum of variation from the mean value of baseline measured in the period with positive symptoms (dots). The maximum variation of ΔLF/HF indicated the maximum variation from the mean value of baseline measured in the period with positive symptoms (arrow). HF was analyzed in the same way.</p

Hypothesized mechanism of exacerbated symptoms and increased sympathetic nerve activity before defecation.

The stress of abdominal pain activates the amygdala to release corticotrophin-releasing hormone (CRH), resulting in further exacerbation of abdominal pain by increasing colonic motility. These cascades “exacerbate the circle of pain.” Two minutes before defecation, the stress also activates sympathetic nerves as a stress response against abdominal pain. Increased sympathetic nerve activity can decrease colonic motility, which may have a protective role to hold back the defecation. This situation may be under competition between the accelerator of colonic motility caused by CRH and the brake caused by sympathetic nerve activation.</p

Data sheet of study participants.

(CSV)</p

Changes in the levels of hemoglobin and albumin after treatment with placebo or rebamipide.

<p>Results are expressed as medians and interquartile ranges (IQRs)</p><p>Changes in the levels of hemoglobin and albumin after treatment with placebo or rebamipide.</p

Changes in the number of small intestinal mucosal breaks from baseline to posttreatment.

<p>Results were analyzed by the Wilcoxon signed-rank test.</p