Instructions: Read the following passage, and answer the questions that follow. The Answer box at the bottom of the choices will tell you if your answer is correct.
Passage 1 of 1
Is tissue engineering a viable medical option to permanently repair damage to the body? This passage was adapted from Piece by Piece by Randall
C. Willis. Modern Drug Discovery, September 2004.
In the two decades since chemical engineering professor Robert
Langer and surgeon Joseph Vacanti first proposed tissue engineering as a panacea for many
human ailments, enthusiasm for the field has ebbed and flowed. While some researchers have
focused on its potential to replace lost organ function, allowing patients to get rid of dialysis
machines, insulin needles, and walkers, others have looked at parallel advances in therapeutics
and mechanical prosthetics and argued that the return on investment was too low for the field
to grow. The reality lies somewhere in between.
David Williams, a researcher at the U.K. Centre for Tissue Engineering,
recently described the field as, "The essence of tissue engineering is that those cells
capable of initiating and sustaining the regeneration process are 'switched on,'
(… ) so that they generate new functional tissue of the required variety."
For years, engineers have been developing mechanical devices
to replace many body functions. Why should a physician fix an arrhythmic heart with modified
cardiac tissue when a pacemaker works so well? Why should an arthroscopic surgeon replace
joint cartilage with bioengineered tissues when knee replacement surgery is so successful?
As Williams explains it, "We have, therefore, a situation
in which the costs of the development of tissue engineering and regenerative medicine will
have pharmaceutical dimensions (i.e., high research and development costs), but with rewards
that will be similar to those associated with the conventional medical devices they are replacing."
Pacemakers and mechanical knee joints, however, wear out and
need to be replaced. As a result, researchers and clinicians are looking beyond these measures
designed to alleviate human suffering for a span of years or, at most, decades. Instead, they
are trying to identify ways in which they can repair damage to the body permanently, by allowing
it to incorporate healthy tissue capable of regeneration.
