国家自然科学基金81302160,81272447;国家消化系统疾病临床医学研究中心基金2015BAI13B09;北京市自然科学基金7152043 . This study was supported by National Natural Science Foundation of China81302160,81272447;National Clinical Research Center for Digestive Diseases2015BAI13B09;Natural Science Foundation of Beijing7152043