Determinants of Vascular Calcification in Chronic Renal Failure : Impact of Pyrophosphate Levels After Renal Transplantation (PyroCal-greffe)

Arterial calcifications (AC) are constant lesions in patients with Chronic Kidney Diseases (CKD). Renal transplantation would reduce their progression compared to dialysis. AC pathophysiology is a complex and finely regulated process that involves many local and systemic factors, both pro- and anti-calcification. The progression of the CKD is accompanied by an increase in phosphate levels as the renal excretion capacity of inorganic phosphates (Pi) decreases while their digestive absorption remains unchanged. Hyperphosphatremia is a well-identified calcifying factor contributing to ACs in the CKD. On the other hand, pyrophosphate (PPi) is an anti-calcifying factor from the hydrolysis of extracellular ATP by ectonucleotidases. While there are many factors that may contribute to a protective effect against AC progression of renal transplantation, no study has been yet analysed the role of PPi. Plasma concentration of PPi is decreased in dialysis patients compared to non-kidney failure patients.

The main objective of this monocentric, prospective and interventional pilot study will be to compare the progression of CA and [PPi]pl between a group of renal transplant patients over the past 24 months and a group of dialysis patients over the same period of time. The secondary objectives will be to compare the progression of ACs and the ratio[PPi]pl/[Pi]pl between transplanted and dialysis patients. Transplanted patients will be included within 24 (±3) months of transplant. Dialysis patients will be included at 24 (±3) months of the CT scan performed during the pre-transplant check-up. At inclusion, all patients will benefit from a CT scan without injection and a plasma dose of PPi, Pi and other factors involved in controlling calcification.

Study Overview

• Status: Completed
• Conditions: Chronic Kidney Diseases
• Intervention / Treatment: Procedure: Blood collection for Ppi assay; Radiation: CT Scan

• Study Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Nice, France, 06001
    • Hôpital Pasteur - Unité d'Exploration Fonctionelle Vasculaire

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Kidney transplant patients for 24 (±3) months or dialysis patients who have performed pre-transplant CT for 24 (±3) months
• Major Patients
• Informed patients who have signed informed consent
• Patients of both sexes
• Patients affiliated to the social security system

Exclusion Criteria:

• Pregnancy in progress (checked by a previous ßHCG pregnancy test)
• Patients whose clinical condition would not allow inclusion in the study.
• Patients not affiliated with social security
• Patients not consenting or unable to understand the protocol and its development
• Progressive cancer pathology
• Patients under guardianship, under curatorship, protected by law

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Kidney transplant patients; Group of renal transplant patients for 24 months	Procedure: Blood collection for Ppi assay; A 4.5 ml blood sample will be taken with a citrate vacuum tube.; Radiation: CT Scan; A scanner will be performed
Other: Dialysis patients; Group of dialysis patients for 24 months	Procedure: Blood collection for Ppi assay; A 4.5 ml blood sample will be taken with a citrate vacuum tube.; Radiation: CT Scan; A scanner will be performed

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentration of plasma PPi		at patient inclusion
Calcification score	The calcification score is based on a computed tomography (CT) scan.	at patient inclusion

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire de Nice
• Investigators: Principal Investigator: Georges LEFTHERIOTIS, PU-PH, Centre Hospitalier Universitaire de Nice

Study record dates

Study Major Dates

• Study Start (Actual): September 10, 2018
• Primary Completion (Actual): October 28, 2019
• Study Completion (Actual): October 28, 2020

Study Registration Dates

• First Submitted: January 12, 2018
• First Submitted That Met QC Criteria: March 9, 2018
• First Posted (Actual): March 12, 2018

Study Record Updates

• Last Update Posted (Estimate): May 8, 2023
• Last Update Submitted That Met QC Criteria: May 5, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Urologic Diseases; Calcium Metabolism Disorders; Calcinosis; Kidney Diseases; Renal Insufficiency, Chronic; Kidney Failure, Chronic; Renal Insufficiency; Vascular Calcification
• Other Study ID Numbers: 17-AOI-02

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No