Increased expression of brain-derived neurotrophic factor is correlated with visceral hypersensitivity in patients with diarrhea-predominant irritable bowel syndrome

Table 1 Demorgraphics, clinical characteristics and psychological states of patients with diarrhea-predominant irritable bowel syndrome and healthy controls

Feature	IBS-D patients	Controls	P-value
N	31	20	NA
Age (yr)	33.0 (29.0-42.0)	28.0 (26.0-36.0)	0.056
Gender (male:female)	22:09	13:07	0.654
Body mass index (kg/m2)	24.2 ± 4.3	22.2 ± 2.6	0.095
Duration of disease (yr)	5.0 (2.0-10.0)	NA	NA
IBS-SSS	274.2 ± 29.8	NA	NA
Severity of abdominal pain	1.0 (1.0-2.0)	NA	NA
VSI score	54.0 (44.0-61.0)a	21.0 (17.3-30.0)	< 0.001
HADS anxiety score	6.0 (2.0-10.0)a	3.0 (1.0-4.0)	0.003
HADS depression score	4.0 (1.0-8.0)	2.5 (1.3-4.0)	0.055

^aP < 0.01 vs controls. The data are presented as the mean ± standard deviation or median (interquartile range). IBS-D: Diarrhea-predominant irritable bowel syndrome; IBS-SSS: IBS Symptom Severity Scale; VSI: Visceral sensitivity index; HADS: Hospital Anxiety and Depression Scale; NA: Not applicable.

Table 2 Correlations between brain-derived neurotrophic factor levels and clinical and experimental parameters in patients with diarrhea-predominant irritable bowel syndrome

	BDNF expression
Clinical characteristic
Severity of abdominal pain	0.565 (0.001)a
IBS-SSS	0.393 (0.029)b
Visceral sensitivity
First sensation threshold	-0.562 (0.001)a
Defecating sensation threshold	-0.015 (0.938)
Maximum tolerable threshold	-0.290 (0.113)
RAIR threshold	-0.508 (0.004)a
Mucosal nerve fiber density	-0.058 (0.756)

Spearman’s correlation coefficients are presented with P-values in parentheses.

^aP with significance after Bonferroni correction (adjusted P < 0.0071).

^bP without significance after Bonferroni correction (adjusted P < 0.0071). BDNF: Brain-derived neurotrophic factor; IBS-SSS: IBS Symptom Severity Scale; RAIR: Rectoanal inhibition reflex.

Table 3 Correlations between brain-derived neurotrophic factor level and clinical and experimental parameters in all subjects

	BDNF expression
Visceral sensitivity
First sensation threshold	-0.557 (< 0.001)a
Defecating sensation threshold	-0.196 (0.168)
Maximum tolerable threshold	-0.453 (0.001)a
RAIR threshold	-0.447 (0.001)a
Mucosal nerve fiber density	0.059 (0.681)

Pearson or Spearman’s correlation coefficients are presented with P-values in parentheses.

^aP with significance after Bonferroni correction (adjusted P < 0.01). BDNF: Brain-derived neurotrophic factor; RAIR: Rectoanal inhibition reflex.