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Role of the Oral Microbiome in Blood Pressure Regulation in Pregnancy

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ClinicalTrials.gov Identifier: NCT03930693
Recruitment Status : Not yet recruiting
First Posted : April 29, 2019
Last Update Posted : April 29, 2019
Sponsor:
Information provided by (Responsible Party):
Dr Jenny Myers, University of Manchester

Brief Summary:

High blood pressure in pregnancy is associated with poor outcomes for both mum and baby, increasing the risk of pregnancy complications including pre-eclampsia, fetal growth restriction and preterm birth. The development of new blood pressure lowering interventions suitable for use in pregnancy is a key research priority.

Inorganic nitrate is a compound found in certain types of food, particularly green leafy vegetables and beetroot. Nitrate provides an important source of nitric oxide (NO), a molecule involved in keeping blood vessels healthy and regulating blood pressure. Supplementation with nitrate in the diet, using interventions such as beetroot juice, has been shown to reduce blood pressure and improve blood vessel function.

In order for dietary nitrate to have these beneficial effects, it needs to be converted in the body to nitrite, via bacteria that live in the mouth (oral bacteria). Differences in oral bacteria, and how they metabolise nitrate, are thought to influence blood pressure regulation and potentially response to dietary nitrate supplementation.

This study aims to understand (1) whether pregnant women with high blood pressure have a different composition of oral bacteria compared to healthy pregnant women and women who are not pregnant, and (2) how differences in oral bacteria affect blood pressure responses to a dose of dietary nitrate (in the form of beetroot juice).


Condition or disease Intervention/treatment Phase
Gestational Hypertension Dietary Supplement: Beetroot juice Early Phase 1

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 160 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Investigation of the Oral Microbiome in Pregnancy - do Differences in Oral Bacterial Profiles and Nitrate Metabolism Contribute to Blood Pressure Regulation in Pregnant Women?
Estimated Study Start Date : May 2019
Estimated Primary Completion Date : December 2020
Estimated Study Completion Date : June 2021

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Normotensive pregnant women
Normotensive pregnant women
Dietary Supplement: Beetroot juice
Beetroot juice shot (70mL containing 400mg inorganic nitrate)

Experimental: Hypertensive pregnant women
Hypertensive pregnant women
Dietary Supplement: Beetroot juice
Beetroot juice shot (70mL containing 400mg inorganic nitrate)

Experimental: Normotensive non-pregnant women
Normotensive non-pregnant women
Dietary Supplement: Beetroot juice
Beetroot juice shot (70mL containing 400mg inorganic nitrate)

Experimental: Hypertensive non-pregnant women
Hypertensive non-pregnant women
Dietary Supplement: Beetroot juice
Beetroot juice shot (70mL containing 400mg inorganic nitrate)




Primary Outcome Measures :
  1. Quantity of oral nitrate reducing bacterial species [ Time Frame: Baseline ]
    Assessment of oral bacterial profile using next-generation sequencing (bacterial 16S rRNA sequencing)

  2. Oral bacterial nitrate reductase activity [ Time Frame: Baseline ]
    Assessment of oral nitrate reductase activity, measured using enzyme assay

  3. Difference between groups in nitrate/nitrite concentrations before and after dietary nitrate dose [ Time Frame: Baseline to 2.5 hour post-nitrate dose ]
    Measurement of plasma and salivary nitrate and nitrite concentrations, using high-performance liquid chromatography (HPLC)


Secondary Outcome Measures :
  1. Difference between groups in blood pressure response to dietary nitrate dose [ Time Frame: Baseline to 2.5 hour post-nitrate dose ]
    Change in blood pressure


Other Outcome Measures:
  1. Correlation between salivary nitrate reductase activities and the change in salivary/plasma nitrite concentrations post-nitrate dose [ Time Frame: Baseline to 2.5 hour post-nitrate dose ]
    Change in nitrite vs. baseline nitrate reductase activity

  2. Correlation between changes in plasma nitrite concentrations and blood pressure lowering post-nitrate dose [ Time Frame: Baseline to 2.5 hour post-nitrate dose ]
    Change in plasma nitrite vs. change in blood pressure



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Ages Eligible for Study:   16 Years to 45 Years   (Child, Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Normotensive or hypertensive women (hypertension as systolic blood pressure >140 mmHg and/or diastolic blood pressure >90 mmHg OR on anti-hypertensive medication)
  • For pregnant women, between 20-28 weeks gestation

Exclusion Criteria:

  • Multi-fetal pregnancy (for pregnant women)
  • Age under 16, or over 45 years of age
  • Lacking ability to consent
  • Pre-existing diabetes (Type 1/Type 2)
  • Previous history of pre-term FGR (delivery before 32 weeks with FGR)
  • Current tobacco smoker
  • Body Mass Index greater than or equal to 40 or less than or equal to 18
  • Use of any of the following drugs in the last 6 months: systemic antibiotics, antifungals, antivirals or antiparasitics (intravenous, intramuscular, or oral)
  • Large doses of commercial probiotics (greater than or equal to 108 cfu or organisms per day) including tablets, capsules, lozenges, chewing gum or powders (ordinary dietary components such as yoghurts do not apply)
  • Evidence of oral disease, assessed on screening proforma (current conditions of: oral candidiasis (thrush); Dental caries (tooth decay); Halitosis; Oral ulcerations/mouth ulcers; Wisdom tooth pain; Chronic dry mouth)
  • Allergy to beetroot juice or lemon juice (both contained within the juice shot)

Information from the National Library of Medicine

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): NCT03930693


Contacts
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Contact: Elizabeth Cottrell, PhD +44 (0) 161 701 6957 elizabeth.cottrell@manchester.ac.uk

Sponsors and Collaborators
University of Manchester
Investigators
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Principal Investigator: Jenny Myers, BM, PhD Manchester University NHS Foundation Trust

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Responsible Party: Dr Jenny Myers, Principal Investigator, University of Manchester
ClinicalTrials.gov Identifier: NCT03930693     History of Changes
Other Study ID Numbers: 246813
First Posted: April 29, 2019    Key Record Dates
Last Update Posted: April 29, 2019
Last Verified: April 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Dr Jenny Myers, University of Manchester:
Pregnancy
hypertension
nitrate
beetroot juice
Additional relevant MeSH terms:
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Hypertension, Pregnancy-Induced
Hypertension
Vascular Diseases
Cardiovascular Diseases
Pregnancy Complications