Expression of aquaporin 8 in colonic epithelium with diarrhoea-predominant irritable bowel syndrome / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>We analysed and compared the aquaporin 8 (AQP8) expression in ascending and descending colon mucosa between patients with diarrhoea-predominant irritable bowel syndrome (D-IBS) and healthy volunteers, in order to study the relationship between the clinical feature of IBS, the expression of AQP8 and the pathological mechanism of D-IBS.</p><p><b>METHODS</b>Specimens were taken from the proximal ascending colon or distal descending colon of D-IBS patients (n = 26) and healthy volunteers (n = 30), and AQP8 mRNA expression of each specimen was determined by fluorescent quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR). In patients with D-IBS, the relationship was analysed between AQP8 expression in both ascending and descending colons and clinical features including gender, age of onset, duration of illness, frequency of defecation, and stool characteristics.</p><p><b>RESULTS</b>Although AQP8 was present in the epithelium of the ascending and descending colons in healthy persons and D-IBS patients, the AQP8 level of the D-IBS patients was significantly lower than that of the healthy persons (P < 0.01 in the ascending colon, P < 0.05 in the descending colon). AQP8 expression was not correlated with the age of patients with D-IBS (P > 0.05 both in the ascending and descending colons) or the age at the onset (P > 0.05 both in the ascending and descending colons), but closely with the duration of illness (P < 0.05 in the ascending colon, P < 0.01 in the descending colon), frequency of defecation (P < 0.01 in the ascending colon, P < 0.05 in the descending colon) and stool characteristics (P < 0.01 in the ascending colon, P > 0.05 in the descending colon).</p><p><b>CONCLUSIONS</b>The decreased AQP8 expression in D-IBS patients indicates that dysfunction of colonic absorption may cause reduced water absorption, loose stool and diarrhoea. The expression of AQP8 may be related to D-IBS.</p>