Advertisement for orthosearch.org.uk
Results 1 - 3 of 3
Results per page:
Applied filters
Research

Include Proceedings
Dates
Year From

Year To
Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 117 - 117
1 Jul 2014
Deschepper M Paquet J Petite H
Full Access

Introduction

The use of mesenchymal stem cells in regenerative medicine remains a promising approach due to the ability of these cells to differentiate into a variety of cell types of mesodermal lineage. Today, however, it is not clear whether long-term differentiation of MSCs is necessary or alternatively whether the benefits of MSCs can be conferred by transitory paracrine effects (via secreted chemical compounds). Human MSCs secrete a broad variety of cytokines, chemokines and growth factors that may potentially be involved in tissue repair. Nevertheless, hMSCs secretome profile is closely related to cells biological and chemical environment (pO2, inflammation, nutrients disponibility…). In the context of stem-cell-based regenerative medicine, upon implantation, hMSC are exposed to stresses such as ischemia, oxidative stress and inflammatory mediators. Knowledge of the paracrine properties of stem cells under hypoxic conditions is essential for planning appropriate strategies that overcome the potential negative impacts of all levels of low oxygen content (from hypoxiato anoxia) leading to ischemia and tissue necrosis pertinent to MSC-based tissue engineered constructs. Since the beneficial effects of stem cells may be confered predominantly indirectly through paracrine mechanisms, the present study was designed to characterise the hMSC secretome and to assess its biological effects considering oxygen level and nutrients disponibility.

Methods

hMSCs were exposed in vitro either to sustain ischemic environment (pO2 ≤ 0.1%, serum deprived), to hypoxia (pO2 ≤ 0.1%, 5g/L glucose) or to normoxic conditions (pO2=21%). We used an hypoxic station (Biospherix, US) to ensure sustained hypoxia during 21 days. Levels of angiogenic, chemo-attractant, inflammatory and immunomodulative mediators were assessed in supernatants using the luminex technology (milliplex KIT, Millipore, USA). The chemo-attractant potential of conditioned media (CM) was assessed in vitro using Boyden chambers (BD, USA). To assess angiogenic potential of CM, HEPC were seeded on matrigel for 18 hours with CM obtained from hMSCs. Functionnality of secreted mediators was also assessed in vivo: briefly, CM media were lyophilyzed on collagen sponges and ectopically implanted in nude mice. Chemo-attraction and vascularization of the implants were determined using histological and CTscan analysis.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 238 - 238
1 Jul 2014
Deschepper M Paquet J Manassero M Logeart-Avramoglou D Bensidhoum M Petite H
Full Access

Summary

In this study, we challenged the current paradigm of human Mesenchymal Stem Cells survival, which assigned a pivotal role to oxygen, by testing the hypothesis that exogenous glucose may be key to their survival.

Introduction

The survival of human mesenchymal stem cells (hMSCs) has elicited a great deal of interest, because it is relevant to the efficacy of engineered tissues. However, to date, hMSCs have not met this promise, in part due to the high death rate of cells upon transplantation. In this study, we challenged the current paradigm of hMSC survival, which assigned a pivotal role to oxygen, by testing the hypothesis that exogenous glucose may be key to hMSC survival.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 70 - 70
1 Jul 2014
Manassero M Viateau V Decambron A Deschepper M Bensidhoum M Logeart D Petite H
Full Access

Summary

Despite similar, early and massive death, hMSCs promote bone formation which was higher in orthotopic than ectopic site suggesting a trophic effect of hMSCs. Ectopic implantation is suitable to evaluate cell survival, but assessment of bone formation requires orthotopic implantation

Introduction

Tissue constructs containing mesenchymal stem cells (MSCs) are appealing strategies for repairing large segmental bone defects but they do not allow consistent bone healing and early and massive MSCs death was identified as a cause of failure. However, little is known about cell survival in the clinical micro-environment encountered during bone healing process, whereas ectopic evaluation is well documented.

In vivo, luciferase-labelled human MSCs survival, within osteoconductive scaffold, was compared in orthotopic and ectopic locations, and bone formation ability of LF-hMSCs-Acropora constructs was evaluated. Interest and limits of each model were highlighted.