Tissue Engineering

Mouse Ears 1997 MIT

Engineering Tissue

 Corneal Tissue Engineering  Blood vessel tissue engineering  Liver tissue engineering  Cartilage tissue engineering  Bone tissue engineering

Key Factors involving tissue engineering Cell Culture ( stem cell, osteoblast, chondrocyte, hepatocyte Signaling Molecules (Growth Factors, proteins Scaffold ( ceramics collagen, polymers) Tissue/Organ regeneration Interactive traids of responsive cells Supportive matrix Bioactive molecules promoting differentiation and regeneration

Application of tissue engineering 3D culture  Transplantation  Cellular and tissue bases product  Alternative to animal test

Developing procedures used in cartilage tissue engineering 1st generation2nd generation3rd generation Principle approach Autologous cell transplant Performed tissue flaps 3D construct In vivo regeneration and guided tissue repair Important component Periosteal flaps( 修補 組織 骨骼 ) Delivery substances and scaffold( 體內重新 建構 ) Growth factors and biomaterials( 體內再 生 )

Cartilage Tissue Engineering I.Autologous chondrocyte 1. Isolation of tissue sample from patients 2. Tissue regeneration by precursor cells or embryonic stem cells  articular cartilage repair, nasal septal cartilage scaffolds for cartilage for tissue repair

ECM ( Extra cellular Matrix) ECM interaction directly influence cell signaling via cell adhesion molecules such as integrin and cadhedrin, fibronectin, collagen, laminin….

Extracellular Matrix in relation to epithelium endothelium and connective tissue Epithelial cell Basement membrane Endothelial lining the capillary Connective tissue with interatitial matrix Fibroblast

Steering Stem Cell Differentiation Differentiation of stem cells induced by binding to extracellular matrix components (e.g. proteins such as fibronectin, collagen and laminin)components

II. Scaffold for tissue construction 1. Act as shape and guidance template for in vitro and in vivo tissue development 2. Permit 3D immobilization and maintain differentiation materials: hyaluronic acid, collagen, alginate, chutosan, synthetic biodegradable poly(  - hydroxy ester) polyacetic acid,( PLIA), polyglycolic acid( PGA), PLGA……

Chondrocyte or Mesenchyma stem cell Polymer fiber Embedding medium ( hydrogel)

Biosynthetic scaffolds Collagen scafold

Tissue scafold + Cells and Growth factors In vivo transplant

Engineering Organs from Scratch

Tissue in cardiovascular structure Advantages: 1.Avoid repeat operation 2.No rejection by the patients immune system 3.Cells behave like endothelial cells may have low thrombus formation and low infection i.e. valves, blood vessels, vascular patches

Basic steps in tissue engineering of a cardiac valve Bone marrow cells harvest Valve scaffold Cell- scaffold construct

Approaches to create a vascular graft Cross linking Exogenous chemicals Mechanical stimulations Cells + tubular scaffold Endothelial lining In vivo implantation Smooth muscle cells progenitor cells collagen gel/elastin fibrin Extra cellular matrix Biodegradable polymers Autulogous EC Circulating EPC Allogenic EC Embryonic stem cell Non-thromgenicity Immune response Remodeling American Journal of Transplantation 2004; 4 (Suppl. 6): 36–42

e79cd210VgnVCM fRCRD#tab-Videos/09347_00 How to Build a Beating Heart tos/ be79cd210VgnVCM fRCRD#tab- Videos/10008_00 tos/ be79cd210VgnVCM fRCRD#tab- Videos/09346_00

Artificial skin skin substitute  Adhere to the substrate,  Durable and sufficiently elastic  Tolerate some deformation  Allow evaporative water loss  Provide a microbial barrier  Promote homeostasis  Easy to use  Readily available immediately after injury, and elicit a  Regeneration-like response from the wound bed without evoking an inflammatory, foreign-body, or non- self immunologic reaction.

Annu. Rev. Med :231–244

Artificial skin

Therapy using Artificial skin

MSC (Mesenchyma Stem Cells)  Proliferate in cultures  Differentiate into multiple mesenchyma lineage ie. correction of genetic disorder of, i.e bone cartilage

Cell seeding on cotton gauze framed collagen substratum Formation of multilayer mesenchyma cells Physical detachment 3D culture Preparation of 3-D mesenchyma cells

Seeding of mesenchyma cells confluent mesenchyma cells Seeding of epithelial cells Coculture of epithelial and mesenchyma cells Detachment of epithelial cells –attached mesenchyma cell sheet Formation of hetero-spheroid Preparation of 3-D mesenchyma cells

Osteoblast  Arise from mesenchyma cells( MSC)  MSC may be differentiate into osteoblast in vitro  Cultured osteoblast may form extracellular matrix in culture

Bone marrow derived osteoblast Cultured bone T. Uemura et al. / Biomaterials 24 (2003) 2277–2286 Transplantation of cultured bone cells

Bone marrow derived osteoblast Cultured bone Transplantation of cultured bone cells T. Uemura et al. / Biomaterials 24 (2003) 2277–2286

Elastomeric PGS Scaffolds in Arterial Tissue Engineering Tissue Engineering -- Building Body Parts