Tissue EngineeringTissue Engineering

By: Cassie Kuchta & Tim By: Cassie Kuchta & Tim RohmanRohman

There are approximately 500,000 There are approximately 500,000 surgical procedures performed every surgical procedures performed every year in the U.S. which require bone year in the U.S. which require bone substitutes. substitutes.

Currently available bone substitutes, Currently available bone substitutes, including autografts, allografts, and including autografts, allografts, and synthetic materials, are the most synthetic materials, are the most implanted materials second only to implanted materials second only to transfused blood products. transfused blood products.

Rapid Fabrication of Engineered Bone

AutograftAutograft

A graft, or portion of living tissue, A graft, or portion of living tissue, taken from one part of the body taken from one part of the body and placed in another site on the and placed in another site on the same individual. same individual.

AllograftAllograft

Grafts between two or more Grafts between two or more individuals allogenic (genetically individuals allogenic (genetically different although belonging to or different although belonging to or obtained from the same species) obtained from the same species) at one or more loci. at one or more loci.

A bone graft is a piece of bone transplanted A bone graft is a piece of bone transplanted to another part of the skeleton where it is to another part of the skeleton where it is needed to improve function or strengthen needed to improve function or strengthen the structure of the area. the structure of the area.

Sometimes a bone graft is taken from a Sometimes a bone graft is taken from a cadaver, but usually it is harvested from cadaver, but usually it is harvested from the patient for which it will be used. the patient for which it will be used.

Bone grafts are typically harvested from Bone grafts are typically harvested from the patient's iliac crest (top of the hip the patient's iliac crest (top of the hip bone), ribs, or fibula in the lower leg. bone), ribs, or fibula in the lower leg.

This can be quite painful and the This can be quite painful and the complication rate can be high. complication rate can be high. Approximately 40% of spine fusion patients Approximately 40% of spine fusion patients complain of pain at the harvest site for as complain of pain at the harvest site for as long as five years after surgery. long as five years after surgery.

when people with liver failure can be cured when people with liver failure can be cured with implanted "neo-organs" made of liver with implanted "neo-organs" made of liver cells and plastic fiberscells and plastic fibers

when insulin-dependent diabetics will not when insulin-dependent diabetics will not have to take frequent insulin injections have to take frequent insulin injections because they have semi-synthetic because they have semi-synthetic replacement pancreasesreplacement pancreases

when kidney dialysis machines are obsolete when kidney dialysis machines are obsolete because anyone with damaged kidneys can because anyone with damaged kidneys can be outfitted with new ones grown from their be outfitted with new ones grown from their very own cells. Sound like science fiction?very own cells. Sound like science fiction?

Imagine a day…

…this day might not be as far away as you think…..

What is tissue What is tissue engineering?engineering?

a multidisciplinary/interdisciplinary field a multidisciplinary/interdisciplinary field that applies the principles of biology and that applies the principles of biology and engineering to develop tissue substitutes engineering to develop tissue substitutes to restore, maintain, or improve the to restore, maintain, or improve the function of diseased or damaged human function of diseased or damaged human tissues. tissues.

one of the goals of tissue engineering is to one of the goals of tissue engineering is to develop methods to construct organs in develop methods to construct organs in the laboratory that can subsequently be the laboratory that can subsequently be used in medical applications. used in medical applications.

(1) start building material (e.g., extracellular (1) start building material (e.g., extracellular matrix, biodegradable polymer), matrix, biodegradable polymer),

(2) shape it as needed (2) shape it as needed (3) seed it with living cells (3) seed it with living cells (4) bathe it with growth factors(4) bathe it with growth factors(5) cells multiply & fill up the scaffold & grow (5) cells multiply & fill up the scaffold & grow

into three-dimensional tissue into three-dimensional tissue (6) implanted in the body(6) implanted in the body(7) cells recreate their intended tissue (7) cells recreate their intended tissue

functionsfunctions(8) blood vessels attach themselves to the (8) blood vessels attach themselves to the

new tissuenew tissue(9) the scaffold dissolves(9) the scaffold dissolves(10) the newly grown tissue eventually blends (10) the newly grown tissue eventually blends

in with its surroundingsin with its surroundings

Process for Tissue Engineering

Tissue engineers use two Tissue engineers use two methods to engineer tissues:methods to engineer tissues:

First scenario:First scenario:

tissue engineer injects or places a tissue engineer injects or places a given molecule, such as a growth given molecule, such as a growth factor, into a wound or an organ that factor, into a wound or an organ that requires regenerationrequires regeneration

these molecules cause the patient's these molecules cause the patient's own cells to migrate into the wound own cells to migrate into the wound sitesite

after migration the cells turn into the after migration the cells turn into the right type of cell and regenerate the right type of cell and regenerate the tissuetissue

Second scenario:Second scenario:

more ambitious proceduremore ambitious procedure patient receives cells - either his or her own or those of patient receives cells - either his or her own or those of

a donor - that have been harvested previously and a donor - that have been harvested previously and incorporated into three-dimensional scaffolds of incorporated into three-dimensional scaffolds of biodegradable polymers, such as those used to make biodegradable polymers, such as those used to make dissolvable suturesdissolvable sutures

the entire structure of cells and scaffolding is the entire structure of cells and scaffolding is transplanted into the wound sitetransplanted into the wound site

the cells replicate, reorganize and form new tissuethe cells replicate, reorganize and form new tissue at the same time, the artificial polymers break down, at the same time, the artificial polymers break down,

leaving only a completely natural final product in the leaving only a completely natural final product in the body - a neo-organbody - a neo-organ

the creation of neo-organs applies the basic knowledge the creation of neo-organs applies the basic knowledge gained in biology over the past few decades to the gained in biology over the past few decades to the problems of tissue and organ reconstruction, just as problems of tissue and organ reconstruction, just as advances in materials science make possible entirely advances in materials science make possible entirely new types of architectural design new types of architectural design

Why We Need Tissue Why We Need Tissue EngineeringEngineering

fewer livers available for transplant than fewer livers available for transplant than there are patients waiting for new liversthere are patients waiting for new livers

a strategy for construction of the organ a strategy for construction of the organ must be developedmust be developed

tissue engineering holds the promise of tissue engineering holds the promise of producing better organs for transplantproducing better organs for transplant

using tissue engineering techniques and using tissue engineering techniques and gene therapy it may be possible to gene therapy it may be possible to correct many otherwise incurable correct many otherwise incurable genetic defectsgenetic defects

artificial tissues can revolutionize artificial tissues can revolutionize health care by providing a supply of soft health care by providing a supply of soft and hard connective tissues on demandand hard connective tissues on demand

Other applications include Other applications include replacement of lost skin; replacement or replacement of lost skin; replacement or repair of defective or damaged bones, repair of defective or damaged bones, cartilage, connective tissue, or cartilage, connective tissue, or intervertebral discs; replacement of intervertebral discs; replacement of worn and poorly functioning tissues (i.e. worn and poorly functioning tissues (i.e. aged muscles or corneas); replacement aged muscles or corneas); replacement of damaged blood vessels; and of damaged blood vessels; and restoration of cells that produce critical restoration of cells that produce critical enzymes, hormones, and other enzymes, hormones, and other metabolites.metabolites.

BenefitsBenefits

reduced costs w/ use of less reduced costs w/ use of less expensive treatments expensive treatments dramatic improvements in dramatic improvements in treatment outcomes treatment outcomes improved quality of life for improved quality of life for patientspatients

Works CitedWorks Cited

http://www.nuigalway.ie/faculties_departments/anatomy/tissue_engineering.html#More

http://www-2.cs.cmu.edu/~tissue/

http://www.mrsec.umn.edu/mrsec/artificialtissues.shtml

http://serendip.brynmawr.edu/biology/b103/f00/web3/barrera3.html