Home > Bone Tissue Engineering > In vitro study of the combination of CaP or CaP/Collagen composite scaffolds seeded with osteoprogenitor cells to correlate scaffold characteristics with bone formation

In vitro study of the combination of CaP or CaP/Collagen composite scaffolds seeded with osteoprogenitor cells to correlate scaffold characteristics with bone formation

This is the title of my thesis. To explain this i’m gonna start from zero.

 

In tissue engineering you try to regenerate viable tissue of your body. This in contrast to prosthesis’s where you are looking for permanent substitutes for some body parts. When it comes to bone tissue engineering BTE we are searching for possible solutions to recover bone defects. In summary our body needs three things to make new bone. This is what they call:

– Osteoconduction: cells make bone, only when they have a matrix where they can attach to.

– Osteoinduction: in order to produce bone you have to attract specific cells to the defect site and cells have to be stimulated to produce bone and differentiate to the right cells.

– Osteogenesis: this is the process where cells excrete an extra cellular matrix (that later becomes matured bone) using their abilities and available nutrients.

Now, in BTE we seed cells (can be stem cells or more differentiated cells) on a biodegradable scaffold (a 3D matrix for the cells), culture it as long as necessary and then implant it in the defined body part.

Difficulties are at three different levels:

– Cell characteristics: cells are different and their interaction with the scaffold and growth factors isn’t straight forward.

– Scaffold properties: making a scaffold reproducible and compatible isn’t easy.

– Patient variability: every human is different and reacts different to identical therapies.

Why are we doing all this then? Prosthesis’s are non biodegradable and our bodies can react to this strange element. They only last for a couple of years and replacing substitutes by new ones is very difficult and sometimes even impossible. Just making our ‘own’ body again would be a dream.

What is my job in this study? A possible material for scaffolds is CaP (since it is also the main substance of our bones). Possible useful cells our hPDC’s (cells from the outer periosteum of a bone), because they regulate many repair processes in our body. It are osteoprogenitor cells, which are a sort of bone stem cells. My job is to find a relationship between the scaffold characteristics (especially pore sizes) and their in vitro behavior for bone formation (by examining specific gene expressions).

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  1. 02/12/2012 at 13:44

    This means that you’re practising your thesis in an experimental way, but where do you get this material(CaP) from?

    • 08/12/2012 at 14:06

      CaP is the main mineral structure found in bone. That’s why this is often used as material for scaffolds. Every manufacturer of scaffolds produce this CaP in different pore sizes (varying pore interconnectivity, micro and macro pores, etc…) depending on their manufacturing process. Also supplementary, often natural collagen is used as an extra component in the 3D structure of the scaffold matrix. The CaP is just a chemical substance and is most of the time used as a powder in the production process of the scaffold.

  2. michaeltijskens
    07/12/2012 at 14:00

    Is it possible that a person’s body casts off these elements. If so, is there an alternative technology available?

    • 08/12/2012 at 16:16

      Since the material is resorbable (degradable) it is fully replaced by endogenous tissue matrix after some time after implantation. If it’s gone of course it cannot provoke any rejection by our body. Using allografts (scaffolds from the same or another place from other humans) or xenografts (scaffolds from other species) can cause anti-immune reactions because of the foreign cells in the graft. If they are decellularized this problem is avoided. Prosthesis’ also can cause a reaction by our bodies to this foreign body parts. Since these grafts are permanent, the problem is more serious with this approach. You can always provide medicine to overcome a first time period of immune reaction to the implanted scaffold.

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