Intestinal Microbiome and Extremes of Atherosclerosis

Study Overview
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Brief Summary
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Patients attending stroke prevention clinics and a premature atherosclerosis clinic at University Hospital in London, ON, Canada were recruited to the study. They completed a dietary questionnaire, provided stool samples and had blood drawn to measure plasma levels of metabolites produced by the intestinal bacteria.

Detailed Description
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Patients were phenotyped by their residual score in linear multiple regression with measured carotid plaque burden as the dependent variable and coronary risk factors were predictors. The residual score essentially represents the distance off the regression line of predicted plaque. They were grouped into three categories: Unexplained atherosclerosis (with more plaque than predicted by risk factors; residual score >2); Explained (the amount of plaque predicted by risk factors, residual score >-2 and <2); and Protected (less plaque than predicted by risk factors, residual score <-2). DNA was extracted from stool samples in the lab of Dr. Allen-Vercoe at University of Guelph. RNA makeup of the intestinal microbiome was assessed in the lab of Dr. Gregory Gloor at Western. Plasma levels of trimethylamine n-oxide, p-cresylsulfate, hippuric acid, p-cresyl glucuronide, pheny acetyl glutamine and phenyl sulfate were measured by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry in the lab of Dr. Bradley Urquhart at Western. Nutrient intake over the past year was calculated at the Harvard School of Public Health from the 131 item self-reported and semi-quantitative Harvard Food Frequency Questionnaire (FFQ). Estimated glomerular filtration rate was calculated from the Chronic Kidney Disease Epidemiological (CKD-EPI) equations.

Official Title
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Intestinal Microbiome and Extremes of Atherosclerosis

Conditions
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Gastrointestinal Microbiome, Atherosclerosis, Nutrients, Renal Function

Intervention / Treatment
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* Diagnostic Test: Plasma levels of metabolites
* Behavioral: Dietary questionnaire
* Diagnostic Test: Intestinal microbiome


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients attending stroke prevention clinics and a Premature Atherosclerosis Clinic at University Hospital, London, ON, Canada, with measurements of carotid plaque burden and the risk factors used in the linear regression model. Willing to consent to the protocol approved by the Ethics board Exclusion Criteria: Missing data on variables used in the regression model,

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Unexplained Atherosclerosis phenotype<br>Residual score in linear regression >2 | Diagnostic Test: Plasma levels of metabolites<br>* plasma levels of metabolites<br>Behavioral: Dietary questionnaire<br>* Harvard food frequency questionnaire<br>Diagnostic Test: Intestinal microbiome<br>* amplification and sequencing of 16S rRNA gene variable regions in stool samples<br>|
| Explained Atherosclerosis phenotype<br>Residual score in linear regression <-2, <2 | Diagnostic Test: Plasma levels of metabolites<br>* plasma levels of metabolites<br>Behavioral: Dietary questionnaire<br>* Harvard food frequency questionnaire<br>Diagnostic Test: Intestinal microbiome<br>* amplification and sequencing of 16S rRNA gene variable regions in stool samples<br>|
| Protected Atherosclerosis phenotype<br>Residual score <-2 | Diagnostic Test: Plasma levels of metabolites<br>* plasma levels of metabolites<br>Behavioral: Dietary questionnaire<br>* Harvard food frequency questionnaire<br>Diagnostic Test: Intestinal microbiome<br>* amplification and sequencing of 16S rRNA gene variable regions in stool samples<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma levels of metabolites in the three phenotypes | Plasma levels of trimethylamine n-oxide, p-cresylsulfate, hippuric acid, p-cresyl glucuronide, pheny acetyl glutamine and phenyl sulfate | Day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bacterial profile of the intestinal microbiome | Amplification and sequencing of 16S rRNA gene variable regions | Day 1 | 
| Effect of nutrient intake on plasma levels of metabolites | Nutrient analysis from food frequency questionnaire | Day 1 | 
| Effect of renal function on plasma levels of metabolites | eGFR from CKD-EPI equations | Day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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intestinal microbiome, atherosclerosis, nutrients, renal function