New advanced therapy medicinal product for cartilage defect treatment with extemporaneous association of a scaffold and Wharton's jelly mesenchymal stromal cells
Abstract
n the framework of an ANR project obtained in 2015, we propose to develop a new advanced
therapy medicinal product for cartilage defect treatment with extemporaneous association of a
scaffold and Wharton’s jelly mesenchymal stromal cells (WJ-MSC).
Due to their capacity of proliferation and differentiation, MSC appear to be currently one of the
most promising ways of obtaining cartilage cells. The conjunctive tissue of the umbilical cord
or Wharton’s jelly is an abundant and promising source of MSC for clinical applications. They
present immunomodulatory properties and have a higher proliferation potential than MSC from
adult tissues. All these advantages enable this source to represent a virtually inexhaustible
source of stem cells especially for allogeneic tissue engineering therapies.
The first part of this work made it possible to perform a technological transfer from research
towards the clinic. The transfer consisted in adjusting MSC isolation, production and
conservation methods developed by research lab in clinical grade conditions.
Eight umbilical cords were obtained after the signing of an informed consent form by pregnant
mothers. In parallel, for each umbilical cord collected, well identified obstetric factors were
recorded. We developed a fast, simple and efficient explant method for the isolation of MSC
from human umbilical cords requiring minimal manipulation and thus reducing the risk of
contamination. MSC isolation, production and conservation were performed in a controlled
atmosphere zone. All reagents and materials were well-defined and controlled. Cell culture was
performed in culture containers (CellSTACK®, Macopharma) in a closed system. MSC were
cultivated in hypoxia until passage 2 and then frozen. Quality controls were carried out during
production: serological and microbiological controls, cell number, viability, clonogenic
capacity, immunophenotype, mesodermic differentiation potential and karyotype.
This isolation method showed a 100% success rate. We were able to obtain a large number of
viable and secured cells with an average number of 50.106 cells per CellSTACK and a doubling
time of about 1.5 days. During the culture, WJ-MSC exhibited a sustained clonogenic capacity
and a specific mesenchymal phenotype.
These results made it possible to assess the feasibility and to validate the clinical grade
amplification technique as well as to obtain precisely characterized and secured WJ-MSC.