Professor Walters's principal interests are the Molecular and cellular function of the small intestine -- in particular how the development and differentiation of the mucosal epithelial cells affects nutrient transport. This include the effects of inflammatory diseases of the intestine causing malabsorption, such as coeliac disease and Crohn's disease, and the changes in gene expression during active disease and the repair process.
Recent research has resulted in a paradigm shift in the understanding of chronic Bile Acid Diarrhoea (also known as Bile Salt Malabsorption or Bile Acid Malabsorption). Rather than malabsorption, underproduction of the ileal hormone FGF19 results in excessive hepatic bile acid synthesis, exceeding the normal capacity for absorption. A review showed that about one-third of patients with IBS-D have BAD and this represents around 1% of the adult population.
FGF19 production in the ileum is stimulated by bile acids and this is deficient in patients with BAD. Blood levels of this hormone are low. Drugs known as FXR agonists (obeticholic acid is the first in class) are able to stimulate production of FGF19 and give symptomatic improvement.
Prof. Walters aims to increase the awareness of BAD and to develop new treatments that are well tolerated.
et al., 2015, The response of patients with bile acid diarrhoea to the farnesoid X receptor agonist obeticholic acid, Alimentary Pharmacology & Therapeutics, Vol:41, ISSN:0269-2813, Pages:54-64
Walters JRF, 2014, Bile acid diarrhoea and FGF19: new views on diagnosis, pathogenesis and therapy, Nature Reviews Gastroenterology & Hepatology, Vol:11, ISSN:1759-5045, Pages:426-434
et al., 2013, Fibroblast growth factor 19 in patients with bile acid diarrhoea: a prospective comparison of FGF19 serum assay and SeHCAT retention, Alimentary Pharmacology & Therapeutics, Vol:38, ISSN:0269-2813, Pages:967-976
et al., 2013, Potent stimulation of fibroblast growth factor 19 expression in the human ileum by bile acids, American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol:304, ISSN:0193-1857, Pages:G940-G948
et al., 2012, The Role of Bile After Roux-en-Y Gastric Bypass in Promoting Weight Loss and Improving Glycaemic Control, Endocrinology, Vol:153, ISSN:0013-7227, Pages:3613-3619
et al., 2009, A New Mechanism for Bile Acid Diarrhea: Defective Feedback Inhibition of Bile Acid Biosynthesis, Clinical Gastroenterology and Hepatology, Vol:7, ISSN:1542-3565, Pages:1189-1194
et al., 2009, Systematic review: the prevalence of idiopathic bile acid malabsorption as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome, Alimentary Pharmacology & Therapeutics, Vol:30, ISSN:0269-2813, Pages:707-717
et al., 2008, Increased capsaicin receptor TRPV1-expressing sensory fibres in irritable bowel syndrome and their correlation with abdominal pain, Gut, Vol:57, ISSN:0017-5749, Pages:923-929