Clinical trial NCT03930693: Role of the Oral Microbiome in Blood Pressure Regulation in Pregnancy
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?
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Gestational Hypertension
Keywords: Pregnancy
hypertension
nitrate
beetroot juice
Lead sponsor: University of Manchester
Sponsor class: OTHER
First posted: 2019-04-29
Enrollment: 55
Sex: FEMALE
Minimum age (years): 16
Maximum age (years): 45
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: FACTORIAL
Intervention model description: Beetroot juice intervention given to all participants (1 dose only)
Primary purpose: BASIC_SCIENCE

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).


Eligibility 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)

Primary outcomes:
measure: Quantity of oral nitrate reducing bacterial species
timeFrame: Baseline
measure: Oral bacterial nitrate reductase activity
timeFrame: Baseline
measure: Difference between groups in nitrate/nitrite concentrations before and after dietary nitrate dose
timeFrame: Baseline to 2.5 hour post-nitrate dose
Secondary outcomes:
measure: Difference between groups in blood pressure response to dietary nitrate dose
timeFrame: Baseline to 2.5 hour post-nitrate dose
Other outcomes:
measure: Correlation between salivary nitrate reductase activities and the change in salivary/plasma nitrite concentrations post-nitrate dose
timeFrame: Baseline to 2.5 hour post-nitrate dose
measure: Correlation between changes in plasma nitrite concentrations and blood pressure lowering post-nitrate dose
timeFrame: Baseline to 2.5 hour post-nitrate dose
Locations:
city: Manchester
country: United Kingdom
facility: Maternal and Fetal Health Research Centre, St Mary's Hospital
Study officials:
affiliation: Manchester University NHS Foundation Trust
name: Jenny Myers, BM, PhD
role: PRINCIPAL_INVESTIGATOR
References: