D. Letourneur - amgme

issu e E n g in eerin g. Years. « Biomaterials » and « Tissue Engineering ». From 1982 to 2002 in the "United States National Library of Medicine". Le génie ...
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U 698

NOUVEAU DOMAINE INTEGRANT LES BIOMATERIAUX POLYMERES :

Partie 1 : Biomatériaux

Génie Tissulaire

Partie 2 : Ingénierie tissulaire CHU X. Bichat Paris

Institut Galilée Villetaneuse

Génie Tissulaire

« Tissue Engineering »

« Biomaterials » and « Tissue Engineering » From 1982 to 2002 in the "United States National Library of Medicine"

Biomaterials

Tissue Engineering

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Tissue Engineering

D. Letourneur

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Years

Le génie tissulaire est l’ensemble des technologies utilisant des cellules vivantes et/ou des biomatériaux (synthétiques ou naturels) dans le but de: - reconstruire ou régénerer des tissus et organes humains, - remplacer la fonction d’organes déficients, - de modifier des gènes ou proteines dans le corps humain.

Problématique: Prothèses Vasculaires 1. Greffe de vaisseau autologue 2. Prothèses synthétiques: PTFE ou polyester (Dacron®)

Mais limitations pour petit calibre 

Occlusion par thrombose (surface thrombogène)



Hyperplasie intimale par migration et prolifération des cellules musculaires lisses CML de l’hote (sténose)



Endothélialisation limitée

3. Ou ingénierie tissulaire d’un nouveau vaisseau

Procédé d’obtention de tubes

Ex vivo Experiments : Mechanical Testing

• Rat Physiological Flow Conditions (300 Beats/min; 160 ml/min; 37 °C; 5 cp)

Tubes de diamètres intérieurs et extérieurs modulables homogènes, transparents et manipulables

1st Echo at 1 week

In Vivo Implantation in Rats Evaluation of 1st Generation : Non-seeded Tubes

Aortic Replacement

Résultats in vivo

Blood Flow

Imagerie (Doppler, angiographie)

1st Echo at 1 week 2 mm

1 semaine

2 mois

Mesure du Diamètre Intérieur

Angiographie : 2 mois

Explantation - Histology

Explantation at 2 months Neo-intima formation

Lumen

400 µm

Lumen Collagen

Surface

Inside

Inside

Internal Diameter : 2.7 mm

histology

Gel

Gel Smooth Muscle Cells (α-Actin)

Endothelial Cells (RECA)

Surface

400 µm

First Conclusion New Approach in Tissue Engineering for 2mm-internal diameter vascular prosthesis

FUTURE NEW 3D Matrices made of Biocompatible Polysaccharides.

TISSUE ENGINEERING

But some limitations (such as mechanical properties, suture, …)

BLOOD VESSELS ?

Autres polymères …

ePTFE With 120 mmHg

Our tube

Experimental design adapted from N. L’heureux (www.cytograft.com)

Flux sanguin

Angiography J4

Cellular adhesion : Mesenchymal Stem cells

Après explantation J4

Chaouat et al., Adv Funct. Mater., 2008

ESEM (hydrated gel and living cells)

Day 4  Scaffold allows bone-marrow-derived Mesenchymal Stem Cell adhesion, spreading and proliferation

In vitro cellular infiltration

x63

PKH labeled MSCs (red) FITC-labeled scaffold (green)

3D reconstruction of confocal images Dimensions 1 mm x 1 mm x 200 µm

MSCs (purple) into 3D gels (green)

Beating areas in 3D scaffolds

How to deliver cells to the infarcted myocardium ? Intramyocardial injection

Intracoronary injection

(Ménard C. and al, 2005)

(Cai J. and al, 2007)

Local delivery

Less invasive

But limited engraftment

But limited engraftment microcirculation thrombosis

x10

3D scaffold / cardiac patch

Local and uniform cell delivery Better engraftment

x20

hES-derived cardiomyocytes retain their contractility in 3D conditions for more than 4 weeks

In vivo implantation (rat model)

Transfer of cells into the infarcted area (1 month)

6mm diameter porous scaffold

Scaffold implanted onto

stained with alcian blue

the heart (2 months)

Autofluorescence - Objective x4

Merged image of green autofluorescence and red labeled cells in an infarcted myocardial wall Objective x10

Research & Development of new Biomaterials

Conclusions for cell therapy  Feasibility of delivering cells into the injured myocardium in rats  Scaffold acts as a cell reservoir in the ischemic area  Ongoing investigation: efficacy study in rats and in pigs

Polymers for Cardiovascular Engineering

 Another cell type for cardiac cell therapy ?  Human Embryonic Stem Cells (hES)  Differentiation into cardiac cells  Induce the differentiation of hES cells into cardiac cells in 3D conditions

Chemistry

Engineering

Biology In vitro In vivo

Medical imaging MRI

Cardiovascular Medicine

Polymer Chemistry Characterizations Engineering

Cell Biology Molecular Biology Pharmacology

In vivo Experiments Medical imaging

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For human diseases