such as "Introduction", "Conclusion"..etc
Bioengineers from University of California, San Diego are developing
new regenerative therapies for heart disease that could influence the
way in which regenerative therapies for cardiovascular and other
diseases are treated in the future.
New results from UC San Diego on using adult stem cells to
regenerate heart tissue in environments that mimic a human
post-heart-attack heart were presented in San Diego at the 2009 annual
meeting of the American Society for Cell Biology (ASCB). The work is
from the laboratory of Adam Engler from the Department of
Bioengineering at the UC San Diego Jacobs School of Engineering.
Every year in the United States, approximately 900,000 people die
from heart disease. The prevalence of heart disease has prompted
researchers to develop new regenerative therapies to treat the
condition, including the injection of adult stem cells into the scarred
heart muscle that results from a heart attack. This treatment, called
cellular cardiomyoplasty, relies on injected stem cells receiving
appropriate cues from their surrounding tissue to cause them to become
However, when stem cells are injected into stiff, scarred,
post-heart attack muscle (rather than healthy tissue), these stem cells
do not readily become cardiac muscle. In fact, only marginal
improvement in overall cardiac function has been detected, and this
improvement may not actually be from tissue regeneration. Instead, the
improvements may be from the fact that the treatment "pokes holes" into
the scar tissue and injects soft cells, making it slightly softer and
thus more functional. Even more striking, the injected stem cells do
not form new cardiac muscle. Instead, the stem cells form small
calcified lesions. The injected stem cells are directed by the stiff
scar tissue to mature into bone-like cells rather than new heart cells.
Given these problems associated with direct stem cell injection, the
UC San Diego bioengineers are proposing to use cells placed in a
supportive material that changes stiffness with time by exhibiting
"Our evidence suggests that tissue-specific stiffness arises from
key developmental changes, which implies that cells should be cultured
in the appropriate physical conditions that mimic embryonic tissue
progression, from soft, pre-cardiac tissue at early embryonic age to a
mature, less compliant tissue at the conclusion of development," said
Jennifer Young, a Ph.D. candidate in bioengineering at UC San Diego and
the first author on the peer-reviewed presentation at ASCB 2009. By
tuning this material to mimic in situ time-dependent
stiffness changes, the UC San Diego bioengineers have found that cells
placed in this material indicate improved cardiac differentiation.
"Results from this study may not only have a profound impact on
cardiovascular engineering, but may influence the way in which many
regenerative therapies are conducted. In this instance we have studied
the developing tissue as a model, and from it generated a set of design
criteria to mimic in our new material," said bioengineering professor
Adam Engler from the UC San Diego Jacobs School of Engineering.
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