Bian Zhaoxiang,
Hong Kong Baptist University, Hong Kong
Biography
Prof Bian Zhaoxiang had been educated in Nanjing University of Traditional Chinese Medicine (TCM). Beijing University of TCM and Guangzhou University of
TCM; and was conferred the Ph.D. degree in Integrated Chinese and Western Medicine in 1994. Currently, he is the Associate Vice-President, Chair Professor
of School of Chinese Medicine, Director of Clinical Division and Associate Director of Institute of Creativity of Hong Kong Baptist University. He is also the
Honorary Professor of the Shanghai University of TCM, and the Chinese Academy of Chinese Medical Sciences, China. Prof. Bian's research focuses mainly
on the relationship between psychological stress and digestive diseases, especially on colorectal cancer irritable bowel syndrome (IBS) and inflammatory bowel
disease (IBO) and related new drug discovery and clinical trial design, implementation and reporting with Chinese Medicine.
Abstract
Bile acid (BA) overexcretion, strongly linking with the severity of bowel symptoms, affects a considerable population
of diarrhea-predominant irritable bowel syndrome (IBS-D), Some genetic and metabolic mechanisms derived
from the host have been documented, however the role of gut microbiota has received little attention. To investigate gut
microbiota and its effect on BA metabolism in IBS-D, a series of metabolic and microbial experiments were performed
from bedside to bench. Fecal metagenomic analysis identified a specific enterotype characterized by enrichment of
Clostridium in IBS-D cases with BA overexcretion. Abundant Clostridium species showed positive association with
human fecal total BA and serum C4 levels, but reversely correlated with serum FGF19. Further, mouse experiments
with bacterial manipulation found that enrichment of Clostridium species in the cecal lumens leads to elevation of fecal
total BA level and taurine-conjugated BA contents in the liver and ileal contents, along with differential expressions of
hepatic BA synthetase CYP7A1 and ileal feedback regulator FGF15. Mechanistic analyses revealed such microbiotadriven
BA synthetic dysregulation is involved in inhibition of FXR-mediated feedback signaling. This study discloses the
potential contribution of Clostridium-enriched enterotype in BA overexcretion in IBS-D and also suggest the importance
of enterotype classification in pathogenesis and diagnosis for IBS.