Quiz 6 Cell & Tissue Engineering

Current methods to treat loss of organ functions

• Synthetic implant

  • Restores function BUT can have biocompatibility issues

• Transplantation

  • Restures function BUT can have immunogenetic issues

• TE Treatment

  • Forms new autologous tissue

Transplantation

• Replacement of tissues or complete organs.

  • Limited by risk of rejection due to immunological barrier between donor and host.

Autografting

• Donor & host are the same individual

• A fraction of tissue is harvested and grafted on an injured site

  • Main limitation is the risk of creating a second wound site.

Permanent Prosthetic Devices

• Not applicable to any tissues and organs and risk of toxicity.

Stem Cells

• Unspecialized or partially specialized master cells that can self-renew indefinitely and differentiate into many different functional cell types in the body

In vitro tissue engineering

• Sufficient for synthesis of the avascular, epithelium-like tissues on one side of the basal membrane but not vascularized tissue and or complex tissue layers.

In vivo tissue engineering

• Involves implantating a gel between the periosteum and underlying bone, which enables new bone to be easily harvested for transplantation.

• This approach circumvents many of the disadvantages of harvesting bone from other sites.

Methodology for direct cardiac reprogramming

• By using a combination of factors to reprogram fibroblasts into cardiomyocyte-like cells.

• Factors are injected to the wound site to reprogram locally the fibroblasts.

The cycle of in vitro TE

1. Patient

2. Biopsy

3. Expansion

4. Scaffold

   1. GFs

   2. Cells

5. Stimulation Bioreactor

6. Functional Muscle Construct

7. Transplantation

The cycle of in vivo TE

1. Patient

2. Biopsy

3. Expansion

4. Scaffold

   1. GFs

   2. Cells

5. Transplantation

Mechanotransduction

• The conversion of mechanical signal to a biochemical signal.

• These signals can lead to localized signal transduction for spatial remodeling or cell migration.

3 Parts of Mechanotransduction

• Mechanosensor / mechanoreceptor

  • Primary mechanotransducer. It is stimulated by mechanical force to initiate a biochemical signal.

• Mechanical pathway

  • It transmits mechanical force from the environment to the cell.

• Downstream signaling pathway

  • It transmits and amplifies biochemical signal from the mechanosensor to the desired response.

Methods for combining Mechanical and Biological signals

• Material scaffold

• Mechanical control

• Cellular integration