Molecular Investigation of GENetic Factors in Cardiovascular and Immune-related Traits and Diseases Using a BIOresource of Healthy Volunteers (GENBIO)

Study Overview
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Brief Summary
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The risk of cardiovascular disease is determined by the complex interplay between an individual's genetic make-up, lifestyle, and the environment. The researchers in this observational, cross-sectional, recall-by-genotype study are investigating two potential genetic risk factors; the SWAP70 gene is thought to play a role in the immune response modulating cardiovascular disease risk and the GMPR gene plays a role in red blood cell formation. The investigators hope to identify and characterise distinct molecular and cellular mechanisms underlying candidate functional variants identified in genetic studies of cardiovascular and immune-related human traits and diseases. Healthy volunteers who are part of the NIHR BioResource and have already been genotyped will be invited to the study based on their genotype of the candidate functional variants of interest. Volunteers will attend a single study visit, during which they will complete procedures including a medical, demographic and lifestyle factors questionnaire; height, weight and body fat assessments; in addition to blood pressure/heart rate measurements. A minimally invasive procedure of a venepuncture will be performed to assess the primary objectives of the study. The obtained data may (1) improve understanding of biological and disease mechanisms; (2) identify potential drug targets; and (3) improve insight into the therapeutic potential and limitations of existing and emerging therapies. This study is funded by the UK Medical Research Council, British Heart Foundation and NIHR Cambridge Biomedical Research Centre.

Official Title
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Molecular Investigation of GENetic Factors in Cardiovascular and Immune-related Traits and Diseases Using a BIOresource of Healthy Volunteers

Conditions
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Cardiovascular Diseases

Intervention / Treatment
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* Other: Questionnaire
* Other: Anthropometric measurements: height, weight, and body fat
* Other: Blood pressure and heart rate
* Procedure: Venepuncture (GMPR)
* Procedure: Venepuncture (SWAP70)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Have consented to be part of the NIHR BioResource; Are aged 18 years and above; Have given written informed consent to participate in the GENBIO study; Are carriers or non-carriers of the candidate functional genetic variant(s) of interest. Exclusion Criteria: Have a chronic disease, including cardiovascular diseases, autoimmune diseases and cancer. Additional exclusion criteria to be applied at the discretion/opinion of the CI/collaborator, based on the population of available volunteers for recall and the genetic variant of interest (e.g. allele frequency): Have a biological first-degree relatives (parents, brothers, sisters or children) who are suffering or have suffered from a disease/condition in the opinion of the CI/collaborator that, from a genetic standpoint, may affect the study validity; Are current regular smokers. Regular ex-smokers are suitable if they stopped smoking >10 years ago (regular defined as 1 pack year in both instances); Have ≥3 alcoholic drinks per day; Have a diagnosis of hypertension, or history of consistently high blood pressure readings, e.g. >140/90 mmHg; Have a diagnosis of hypercholesterolemia, or history of consistently high cholesterol levels, e.g. total cholesterol level >6 mmol/l; Are obese (i.e. BMI >30); Are unwilling to fast and not to consume products containing alcohol or caffeine 12 hours prior to procedures.

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| GMPR sub-study<br>Study population will be split into five haplotypes based on a combination of rare and common variants at the GMPR locus. A total of 26 volunteers per genotypic group in a comparison between heterozygous and homozygous individuals will be tested. | Other: Questionnaire<br>* Medical history, demographics and lifestyle factors will be assessed by the participant.<br>Other: Anthropometric measurements: height, weight, and body fat<br>* Height measured by stadiometer. Weight and body fat measured by Tanita scale bioelectrical impedance analysis.<br>Other: Blood pressure and heart rate<br>* Parameters will be measured using a validated, automated device while seated and again after 3-5 min standing. All measurements will be done in triplicate.<br>Procedure: Venepuncture (GMPR)<br>* A blood sample of approximately 50 ml of venous blood will be taken. From the obtained blood sample, measurements will include a full blood count and the following phenotyping tests: Flow cytometry to quantify cell surface expression of key erythroid markers Proteomic analysis of isolated erythrocytes using mass spectrometry<br>|
| SWAP70 sub-study<br>To assess genotype-specific effects on SWAP70 protein levels as well as coronary artery disease-related immune processes, we will recruit 50 volunteers stratified by variant genotype, i.e. major and minor homozygotes only (25 participants will be recruited to each group). | Other: Questionnaire<br>* Medical history, demographics and lifestyle factors will be assessed by the participant.<br>Other: Anthropometric measurements: height, weight, and body fat<br>* Height measured by stadiometer. Weight and body fat measured by Tanita scale bioelectrical impedance analysis.<br>Other: Blood pressure and heart rate<br>* Parameters will be measured using a validated, automated device while seated and again after 3-5 min standing. All measurements will be done in triplicate.<br>Procedure: Venepuncture (SWAP70)<br>* A blood sample of approximately 50 ml of venous blood will be taken. From the obtained blood sample, measurements will include a full blood count and the following phenotyping tests: Flow cytometry to quantify cell surface expression of key markers Fluorescence-Activated Cell Sorting (FACS) to assess B-cell receptor signalling and to isolate cell type-specific RNA for transcriptome analysis Immunoglobulin isotype titre analysis in plasma Isolation of monocytes for subsequent use in phagocytosis assays<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Levels of GMPR protein in isolated erythrocytes | GMPR-specific measurement to be assessed by mass spectrometry, comparing results between different GMPR genotypic groups. | At baseline | 
| Levels of SWAP70 protein in immune cell subsets | SWAP70-specific measurement to be assessed by flow cytometry, comparing results between SWAP70 genotypic groups. | At baseline | 
| Proportion of immune cell types as measured using flow cytometric analysis | SWAP70-specific measurement to be assessed by flow cytometry (e.g. lymphoid and myeloid cell markers), comparing results between SWAP70 genotypic groups. | At baseline | 
| Levels of genes/transcripts in immune cell subsets | SWAP70-specific measurement to be assessed by RNA sequencing, comparing results between SWAP70 genotypic groups. | At baseline | 
| Concentration of immunoglobulin isotypes in plasma | SWAP70-specific measurement to be assessed by immunoglobulin isotype (IgM, IgG, IgA and IgE) analysis, comparing results SWAP70 genotypic groups. | At baseline | 
| Phagocytosis by monocytes as measured by colorimetric analysis (optical density) | SWAP70-specific measurement to be assessed by phagocytosis assays, comparing results between SWAP70 genotypic groups. The phagocytosis assay uses pre-labelled Zymosan particles as a pathogen for triggering phagocytosis. The engulfed Zymosan particles react with a specific substrate to produce a signal that can be detected by colorimetric analysis. | At baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure (systolic and diastolic) | All study arms comparing results between genotypic groups. | At baseline | 
| Heart rate | All study arms comparing results between genotypic groups. | At baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Healthy Volunteers, Genetic Risk Markers for Disease, Coronary Heart Disease, Coronary Artery Disease, Immune Response, Red Blood Cells, Inflammation