This shows the way to a method
for restoring damaged heart tissue. It
is astonishing to see just how swiftly we are progressing in this. At the same time, actual methods to outright
replace a heart with one’s own freshly grown heart is also happening.
The heart is obviously our most
important organ that needs this support, though we will soon be applying
similar methods elsewhere.
As posted earlier we are entering
a brave new world in which damaged components can be grown in vitro with ones
own stem cells and then transplanted into the body in two steps. The first step is to allow the body to
integrate the component and the second step is to remove the damaged component.
The take home is that restoration
will become standard practice inside a few short years now because we are
moving ever faster on this.
MAY 09, 2011
Researchers at Columbia Engineering have established a new method
to patch a damaged heart using a tissue-engineering platform that enables heart
tissue to repair itself. This breakthrough, recently published in the
Proceedings of the National Academy of Sciences (PNAS),
is an important step forward in combating cardiovascular disease, one of the
most serious health problems of our day.
PNAS - Composite scaffold provides a cell delivery platform for cardiovascular repair
Control over cell engraftment, survival, and function remains critical for heart repair.
We have established a tissue
engineering platform for the delivery of human mesenchymal progenitor cells (MPCs)
by a fully biological composite scaffold.
Specifically, we developed a
method for complete decellularization of human myocardium that leaves intact
most elements of the extracellular matrix, as well as the underlying mechanical
properties. A cell–matrix composite was constructed by applying fibrin
hydrogel with suspended cells onto decellularized sheets of human myocardium.
We then implanted this composite
onto the infarct bed in a nude rat model of cardiac infarction. We next
characterized the myogenic and vasculogenic potential of immunoselected human
MPCs and demonstrated that in vitro conditioning with a low concentration of
TGF-β promoted an arteriogenic profile of gene expression. When implanted by
composite scaffold, preconditioned MPCs greatly enhanced vascular network
formation in the infarct bed by mechanisms involving the secretion of paracrine
factors, such as SDF-1, and the migration of MPCs into ischemic myocardium, but
not normal myocardium. Echocardiography demonstrated the recovery of baseline
levels of left ventricular systolic dimensions and contractility when MPCs were
delivered via composite scaffold. This adaptable platform could be readily
extended to the delivery of other reparative cells of interest and used in
quantitative studies of heart repair.
Led by Gordana Vunjak-Novakovic, professor of Biomedical Engineering at
Columbia University’s Fu Foundation School of Engineering and Applied Science,
the researchers developed a novel cell therapy to
treat myocardial infarction (heart damage that follows a heart attack). They
were able, for the first time, to combine the use of human repair cells that
were conditioned during in-vitro culture to maximize their ability to
revascularize and improve blood flow to the infarcted tissue with a fully
biological composite scaffold designed to deliver these cells to the damaged
heart. With this platform, they could both keep the cells within the infarct
bed (in contrast to the massive cell loss associated with infusion of cells
alone) and enhance cell survival and function in the infarct bed, where
most of the cells would have died because of the obstruction of their blood
supply.
“We are very excited about this new technique,” said Dr. Vunjak-Novakovic. “This platform is very adaptable and we believe it could be readily extended to the delivery of other types of human stem cells we are interested in to rebuild the heart muscle and further our research of the mechanisms underlying heart repair.”
In effect, the
“It really is encouraging to make progress with ‘instructing’ cells to form human tissues by providing them with the right environments,” noted Dr. Vunjak-Novakovic. “The cells are the real ‘tissue engineers’—we only design the environments so they can do their work. Because these environments need to mimic the native developmental milieu, the progress in the field is really driven by the interdisciplinary work of bioengineers, stem cell biologists, and clinicians. By enabling regeneration and replacement of our damaged tissues, we can help people live longer and better.”
Dr. Vunjak-Novakovic and her team already have several active research projects that continue this line of work. They are now investigating the formation of a contractile cardiac patch using human stem cells that can give rise to both the muscle and vascular compartments of the heart muscle. They are also studying how the cells within such a cardiac patch, when implanted on infarcted heart tissue, develop their ability to generate mechanical force and electrical conduction, and how these functions can be modulated by in-vitro culture.
“Ultimately, we envision this system as a possible point of care approach,” said Dr. Vunjak-Novakovic, “with components actually produced and assembled in the operating room to most effectively target-signaling mechanisms involved in the repair process of someone’s damaged heart.”
I also added this video. You may need go join Newsy to properly uses it.
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