Diet Modulation of Bacterial Sulfur and Bile Acid Metabolism and Colon Cancer Risk
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|ClinicalTrials.gov Identifier: NCT03550885|
Recruitment Status : Recruiting
First Posted : June 8, 2018
Last Update Posted : July 17, 2019
|Condition or disease||Intervention/treatment||Phase|
|Colorectal Cancer||Other: High taurine and saturated fat diet Other: Low in taurine and saturated fat diet||Not Applicable|
Our research is designed to determine mechanistically why consumption of a high red meat and saturated fat diet imparts risk for CRC development and to demonstrate that primary microbial risk factors (sulfidogenic and bile acid metabolizing bacteria) are modifiable by diet. The focus is on taurine, an overlooked sulfur amino acid (SAA) that is abundant in red meat or provided by bacterial deconjugation of the bile salt TCA, which is increased in subjects consuming a diet high in saturated fat. Rationale for focusing the diet intervention study on AAs comes from the previously mentioned observation that a taurine respiring bacterium distinguished AA but not NHW CRC patients from healthy controls, and the previous work by PI Gaskins in AA subjects focused on mechanisms underlying the increased risk for CRC associated with consumption of a Western type diet.
Our strong collection of past publications and new preliminary data support our hypothesis that dietary sources of organic sulfur increase the abundance of microbes that generate H2S through taurine metabolism and that H2S activates proinflammatory pathways and serves as a genotoxin in the colonic mucosa. We're examining, for the first time bacteria that utilize taurine, which can be provided directly from red meat or indirectly through TCA in response to saturated fat. Our study will be the first to examine the consequences of such specific dietary manipulation on genotoxic or inflammatory pathways implicated in CRC development in at-risk AAs.
Our results will provide novel information regarding the in vivo interactions between diet and cancer that heretofore have not been explored in humans, particularly AAs. Food taurine content is not currently provided in either the University of Minnesota Nutrition Data System for Research (NDSR) or the USDA Standard Reference (USDA SR) nutrient databases, which are the gold standard sources for the nutrient content of food. Evidence that taurine is capable of inducing biomarkers of CRC risk through promoting growth of Sulfidogenic B. wadsworthia or other untargeted bacteria would be an important novel observation justifying the addition of this SAA to these nutrient databases. If our hypothesis is substantiated, simple vigilance of taurine intake might diminish susceptibility to CRC in all individuals, especially AAs at elevated risk. Further, if our hypothesis is upheld, it might be possible to reduce risk not only by dietary intervention but also by microbiota modification (potentially through pre-, pro- or synbiotics). Finally, if our study reveals particular modes of bacterial sulfur or bile acid metabolism correlating with epithelial proliferation or inflammation in AAs, the endpoints identified can potentially predict non-invasively elevated risk individuals who should be: a) advised on specific dietary interventions (those investigated herein); b) offered specific therapy to reduce risk; or c) counseled on regular colonoscopic screening
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||44 participants|
|Intervention Model:||Crossover Assignment|
|Intervention Model Description:||
The proposed study will utilize a randomized, crossover, controlled feeding trial design composed of two experimental diets: (1) animal-based, high in taurine and saturated fat (HT-HSAT) and (2) plant-based, low in both taurine and saturated fat (LT-LSAT) (each consumed for 21 days with a minimum 3-week washout between diets).
At baseline and post-diet (day 22) for each of the two 3-week diets, subjects will undergo a flexible sigmoidoscopy, fasting and non-fasting blood draw, and provide a stool sample.
|Masking Description:||All study personnel, excluding those directly involved with meal preparation, will be blinded to the subjects' diet sequence.|
|Official Title:||Diet Modulation of Bacterial Sulfur and Bile Acid Metabolism and Colon Cancer Risk|
|Actual Study Start Date :||August 1, 2018|
|Estimated Primary Completion Date :||January 2021|
|Estimated Study Completion Date :||August 2021|
Experimental: High taurine and saturated fat diet
This is a 3-week controlled isocaloric diet containing approximately 125 mg taurine, 40% of calories from fat, 15% of calories from saturated fat, 25% of calories from protein (4:1 animal to plant grams of protein), and 11.5 grams fiber/1000 calories.
Other: High taurine and saturated fat diet
This is a 3-week (21 day) isocaloric Western-type diet with all meals, snacks, beverages and condiments provided.
Experimental: Low in taurine and saturated fat diet
This is a 3-week controlled isocaloric diet containing approximately 7 mg taurine, 36% of calories from fat, 8% of calories from saturated fat, 13% of calories from protein (3:1 plant to animal grams of protein), and 13.5 grams fiber/1000 calories.
Other: Low in taurine and saturated fat diet
This is a 3-week (21 day) isocaloric largely plant-based diet with all meals, snacks, beverages and condiments provided.
- Change in the mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]Mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism will be measured by quantitative polymerase chain reaction of 16S rRNA and functional genes with biopsy DNA.
- Change in bile acid metabolism [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]Bile salt hydrolase and bile acid 7a-dehydroxylating activities will be measured in stool samples
- Change in serum bile acids [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]Measurement of serum bile acids using electrospray-ionization mass spectrometry to indicate the extent of taurine-conjugation of bile acids, ratio of conjugated: unconjugated bile acids and levels of secondary bile acids absorbed from the gut
- Change in colonic mucosal inflammation [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]Gene expression of tumor-necrosis factor-alpha, Interleukin-6, and Cox-2
- Change in DNA damage [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]By COMET fluorescence hybridization assay together with in situ staining for 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an oxidative DNA lesion, and the expression of its repair enzyme 8-oxoguanine DNA-glycosylase (OGG1; ab91421), XRCC1 [33-2-5] ab1838), which coordinates the action of DNA ligase III, polymerase beta, and poly-ADP-ribose polymerase in the BER pathway and the apurinic/apyrimidinic endonuclease Ape1 (ab2717), a multifunctional protein that protects cells from oxidative stress via its DNA repair, redox, and transcription regulatory activities
- Change in colonocyte proliferation [ Time Frame: Baseline and post-diet (day 22) for each of the two 3-week diets ]Immunohistochemistry, Ki-67
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03550885
|Contact: Lisa Tussing-Humphreys, PhD, MS, RDfirstname.lastname@example.org|
|Contact: Ece Mutlu, MD, MS, MBA||312-563-3880||Ece_Mutlu@rush.edu|
|United States, Illinois|
|Rush University Medical Center and University of Illinois at Chicago||Recruiting|
|Chicago, Illinois, United States, 60612|
|Contact: Lisa Tussing-Humphreys, PhD, MS, RD 312-355-5521 email@example.com|
|Contact: Ece Mutlu, MD, MS, MBA 312-563-3880 Ece_Mutlu@rush.edu|
|Principal Investigator:||Lisa Tussing-Humphreys, PhD, MS, RD||University of Illinois at Chicago|
|Principal Investigator:||Ece Mutlu, MD, MS, MBA||Rush University Medical Center|
|Principal Investigator:||H. Rex Gaskins, PhD||University of Illinois at Urbana-Champaign|
|Principal Investigator:||Jason Ridlon, PhD||University of Illinois at Urbana-Champaign|