- Tissue damage or injury caused due
to disease or otherwise, is a major health issue
- Tissue engineering offers a
potential solution to addressing tissue damage and failure.
- Currently available vascular grafts
to nourish the new tissue is not fully satisfactory
- New study turns to plants to provide
a potential and viable solution
Plants may be able to help create pre-vascularized scaffolds for tissue
according to a multidisciplinary team of
from Worcester Polytechnic Institute (WPI), the University of
Wisconsin-Madison, and Arkansas State University-Jonesboro.
The team felt that experts from different fields would look at the problem from different
angles for the emergence of novel solutions
The team included experts from
the field of biomedical engineering, biotechnology, human stem cell and plant
‘Prevascularized scaffolds can be made from plants for use in tissue engineering technologies. This provides a sustainable, yet environmental friendly solution.’
Reason for Research
The research team felt that currently available vascular grafts and scaffolds have been unable to
provide an entirely satisfactory solution
of forming a vascular network, to provide nourishment to the implant.
They hope to address the existing gaps in the field by turning to plants in
their new research.
"Plants and animals exploit
fundamentally different approaches to transporting fluids, chemicals and
macromolecules, yet there are surprising similarities in their vascular network
structures," the authors wrote. "The development of decellularized
plants for scaffolding opens up the potential for a new branch of science that
investigates the mimicry between plant and animal."
Details of the Research
- The scientists employed spinach
leaves that were stripped of plant cells leaving behind the transport
- They were able to flow fluids and
microbeads similar in size to the human blood cells successfully.
- They were also able to seed the
spinach venous network with cells that line human blood vessels (endothelial cells)
- Finally, the scientists were able to
cultivate beating human heart cells on these spinach leaves.
These proofs of concept studies may pave the way for
using multiple spinach leaves to generate multiple layers of healthy heart
that could in turn, be
used in heart attack
How the Spinach Leaves Were Stripped of
The paper's first author is Joshua
Gerslak, a graduate student
who was instrumental in designing and conducting the
experiments, and in fact
developed an effective method of decellularizing the spinach leaves, by perfusing
the venous network on the leaf with a detergent solution
"I had done decellularization work
on human hearts before and when I looked at the spinach leaf its stem reminded
me of an aorta. So I thought, let's perfuse right through the stem,"
Gershlak said. "We weren't sure it would work, but it turned out to be
pretty easy and replicable. It's working in many other plants."
Once the plant cells are washed away,
what remains is a framework composed of cellulose
that is bio-compatible
harmful to humans.
Other Leaves that Have Been Used to Form
In addition to spinach leaves, the research team was able to successfully decellularize parsley, Artemesia annua (sweet wormwood),
and peanut hairy roots
. The authors believe that the unique physical
properties of each plant itself could be exploited for use in various tissue
- For instance, spinach leaf might be
apt in a highly vascularized tissue like the heart.
with its hollow cylindrical stem, could be more suited to arterial grafts
- The vascular columns of wood with its innate strength and
geometrical structure might be useful in bone grafts.
"By exploiting the benign chemistry
of plant tissue scaffolds, we could address the many limitations and high costs
of synthetic, complex composite materials. Plants can be easily grown using
good agricultural practices and under controlled environments. By combining
environmentally friendly plant tissue with perfusion-based decellularization,
we have shown that there can be a sustainable solution for pre-vascularized tissue
Current Scenario in Vascular Tissue Engineering
As mentioned earlier, tissue engineering
offers a solution to replace damaged tissues by implantation of natural,
synthetic, or semisynthetic tissue and organ substitutes, that are fully functional initially by itself, or grow into the required
functionality within a limited time span.
- Development of autogenous vascular substitutes have been a major advance in
the field of reconstructive arterial surgery, but these tissue sources are
insufficient or not available. These methods are also time consuming and
- Currently, synthetic polymers such as polytetrafluoroethylene (ePTFE),
polyethylene terephthalate (DacronŪ) and polyurethane are
extensively employed to generate synthetic vascular grafts. However, these are
associated with the risk
of thrombus formation and compliance mismatch, and in addition are non-biodegradable,
though degradable scaffolds are also available, but are expensive.
Future Research Plans
- Optimization of the
- To assess how human tissues grow in
response to various vascular scaffolds
- To generate a secondary vascular
network to permit outflow of blood or fluids from human tissue.
In conclusion, if plant scaffolds prove
successful, we could have a potentially simple,
cheap, compatible and sustainable solution
to the existing gaps in vascular
- Joshua R. Gershlak, Sarah Hernandez, Gianluca
Fontana, Luke R. Perreault, Katrina J. Hansen, Sara A. Larson, Bernard Y.K.
Binder, David M. Dolivo, Tianhong Yang, Tanja Dominko, Marsha W. Rolle, Pamela
J. Weathers, Fabricio Medina-Bolivar, Carole L. Cramer, William L. Murphy,
Glenn R. Gaudette. Crossing kingdoms: Using decellularized plants as perfusable
tissue engineering scaffolds. Biomaterials, 2017; 125: 13 DOI:
- Biomaterials for vascular tissue
engineering - (https:www.ncbi.nlm.nih.gov/pmc/articles/PMC2822541/)