OBJECTIVETo study the correlation between the pulmonary injury and the ET-1 serum level in ulcerative colitis (UC) patients, and to study the mechanism for UC induced pulmonary injury.

METHODSRecruited were 90 UC outpatients from the clinics of Gastroenterology Department, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine from Nov. 2009 to Mar. 2011. The course of disease, disease range, serum ET-1 level of UC patients were observed and compared. The correlation between the serum ET-1 level and each pulmonary function index were studied [including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, peak expiratory flow (PEF), maximal mid expiratory flow (MMEF), maximal expiratory flow in 25%, 50%, 75% vital capacity (FEF25%, 50%, 75%), diffusion capacity for carbon monoxide of lung (DLCO), diffusion constant (KCO), total lung capacity (TLC), alveolar ventilation (VA), residual volume (RV), function residual volume (FRV), and RV/TLC]. Besides, another 30 healthy volunteers were enrolled as the control group. The pulmonary symptoms, chest X-ray, the lung function, the serum ET-1 level, and liver and kidney functions [including alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), serum creatinine (SCr) were compared between the UC group and the control group.

RESULTSTen UC patients were accompanied with cough and chest distress (accounting for 11.1%), 25 with abnormal chest films (accounting for 27.8%), and 54 with pulmonary function abnormality (accounting for 60.0%). In the UC group ALT increased in 2 cases (2.2%) and AST increased in 2. They were normal in the control group. The BUN and SCr were normal in the two groups. Compared with the control group, the serum ET-1 level in the UC group was significantly higher than that in the control group (P < 0.05). There was no statistical difference in the serum ET-1 level (P > 0.05). There was statistical difference in the serum ET-1 level in the UC group between those with the disease course > or = 5 years and those with the disease course <5 years, showing statistical difference (P < 0.05). There was negative correlation between the serum ET-1 level and FEF25% and between the serum ET-1 level and KCO (P < 0.05).

CONCLUSIONSSerum ET-1 level could reflect the pulmonary injury of UC patients earlier. Serum ET-1 level might be a sensitive indicator reflecting the pulmonary injury of UC. The pulmonary injury of UC patients might be correlated with small airway obstruction, reduced lung elasticity, and injured lung diffusion.