Intestinal Microbiota and Vitamin K Levels in PXE Patients (IMPROVE Study)

University Hospital, Angers

Status: Unknown

Conditions: Pseudoxanthoma Elasticum

Treatments: Diagnostic Test: Fecal and blood samples

Study type: Interventional

Funder types: Other

Identifiers

NCT03813550

2018/79

Details and patient eligibility

About

This study aims to demonstrate a potential association between gut microbiota composition, plasma levels of various forms of vitamin K, and severity of clinical manifestations of Pseudoxanthoma Elasticum (PXE).

Full description

Vitamin K deficiency contributes to pathological calcification which underlies the clinical picture of pseudoxanthoma elasticum (PXE), an inherited autosomal recessive disease. A substantial proportion of vitamin K, namely the K2 form (menaquinones), is produced by gut microbiota. In healthy volunteers fecal levels of the major menaquinone producers, Escherichia coli and Bacteroides species, are approximately 5 and 9 log10 CFU/g dry weight respectively. There is however a lack of data on gut microbiota in PXE patients. The objective of our project is to demonstrate a potential association between gut microbiota composition, plasma levels of various forms of vitamin K and severity of clinical manifestations in PXE patients.

This study will be performed as Research surrounding bio collection "Clinical and biological exploration of PXE patients" kept at the Center of Biological Resources of Angers University Hospital (bio collection n° DC 20116-14-67, authorization to transfer n° 2016-27-99). Fecal samples, plasma samples and clinical data will be collected from patients diagnosed with PXE who will be monitored at the Angers University Hospital Referral Center (France) in 2019-2020. Clinical severity of PXE will be assessed using modified Phenodex score. Gut microbiota will be analyzed using metagenomic sequencing. Plasma Vitamin K species and fecal excretion of menaquinones will be assessed using HPLC. Plasma dp-ucMGP (circulating biomarker of vitamin K status) and serum PIVKA-II (protein induced by vitamin K absence-II) will be assessed using immunoassay. Results will be compared to healthy age- and gender-matched controls from the pre-existing Biofortis database.

Enrollment: 20 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients with phenotypically and genetically (ABCC6) proven PXE
• Aged over 18 years
• Written consent obtained for Angers University Hospital (France) PXE bio-collection

Exclusion criteria

• Patients under the age of 18
• Patients unwilling to participate in the study, or unable to sign the bio-collection consent form

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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20 participants in 1 patient group

PXE cohort 2019-2020

Other group

Description:

PXE patient cohort monitored at referral centre from 2019 to 2020: fecal and blood samples

Treatment:

Diagnostic Test: Fecal and blood samples