Serotonin transporter and cholecystokinin in diarrhea-predominant irritable bowel syndrome: Associations with abdominal pain, visceral hypersensitivity and psychological performance

Table 1 Sociodemographic and clinical characteristics in irritable bowel syndrome patients and healthy controls

	IBS-D patients (n = 40)	HC (n = 18)	P value
Age (yr)	44.50 ± 9.27	42.33 ± 12.81	0.47
Male	30 (75%)	13 (72.2%)	0.83
BMI (kg/m2)	23.95 ± 4.06	22.88 ± 2.86	0.33
IBS-SSS	273.25 ± 42.27	NA	NA
VSI	75.78 ± 9.31	53.39 ± 4.49	< 0.001
IBS-QOL	48.85 ± 9.79	NA	NA
HADS(A)	7.78 ± 2.62	2.89 ± 1.02	< 0.001
HADS(D)	6.38 ± 2.43	2.06 ± 0.73	< 0.001
Visceral sensitivity
Initial sensation threshold (mL)	31.00 ± 8.41	52.22 ± 8.09	< 0.001
Defecating sensation threshold (mL)	51.75 ± 13.57	89.44 ± 8.73	< 0.001
Maximum tolerable threshold (mL)	97.25 ± 23.64	171.11 ± 20.83	< 0.001
Severity of abdominal pain
Pain ruler	2.91 ± 1.63	NA	NA
Pain symptom	1.35 ± 0.74	NA	NA
Pain frequency	1.83 ± 1.28	NA	NA

The data are presented as mean ± SD or median (interquartile range). IBS-D: Diarrhea-predominant irritable bowel syndrome; IBS-SSS: Irritable bowel syndrome symptom severity scale; VSI: Visceral sensitivity index; IBS-QOL: Irritable bowel syndrome-specific Quality of Life; HADS: Hospital Anxiety and Depression Scale; HC: Healthy control; NA: Not applicable.

Table 2 The level of cholecystokinin and serotonin transporter in mucosa membrane and plasma

	IBS-D patients (n = 40)	HC (n = 18)	P value
Plasma
CCK	330.88 ± 61.08	208.63 ± 30.65	< 0.001
SERT	14.26 ± 2.94	21.15 ± 2.09	< 0.001
Mucous membrane (RNA)
CCK	2.29 ± 0.30	1.66 ± 0.17	< 0.001
SERT	1.90 ± 0.51	3.03 ± 0.23	< 0.001
Immunohistochemical OA
CCK	0.044 ± 0.007	0.028 ± 0.003	< 0.001
SERT	0.005 ± 0.001	0.010 ± 0.001	< 0.001

The data are presented as mean ± SD. IBS-D: Diarrhea-predominant irritable bowel syndrome; HC: Healthy control; CCK: Cholecystokinin; SERT: Serotonin transporter.

Table 3 The correlations between visceral sensitivity and symptom severity scale, and visceral sensitivity index in diarrhea-predominant irritable bowel syndrome patients

	SSS	VSI
Initial sensation threshold	-0.64	-0.47
Defecating sensation threshold	-0.64	-0.47
Maximum tolerable threshold	-0.64	-0.45

SSS: Symptom severity scale; VSI: Visceral sensitivity index.

Table 4 The correlations between abdominal pain and the level of cholecystokinin in mucosa membrane and plasma

	Pain ruler	Pain symptom	Pain frequency
Plasma CCK	0.97	0.94	0.95
Mucous membrane CCK	0.96	0.93	0.94
OA CCK	0.97	0.93	0.95

CCK: Cholecystokinin.

Table 5 The correlations between abdominal pain, psychological performance and the level of serotonin transporter in mucosa membrane and plasma

	HADS(A)	HADS(D)	HAMA	HAMD	Pain ruler	Pain symptom	Pain frequency
Plasma SERT	-0.97	-0.97	-0.95	-0.92	-0.94	-0.91	-0.92
Mucous membrane SERT	-0.98	-0.99	-0.97	-0.94	-0.96	-0.93	-0.95
OA SERT	-0.97	-0.97	-0.93	-0.91	-0.93	-0.91	-0.90

SERT: Serotonin transporter; HADS: Hospital Anxiety and Depression Scale; HAMA: Hamilton Anxiety Scale; HAMD: Hamilton Depression Scale.