Mussel ‘glue’ protects damaged blood vessels
Alginate molecules are modified with catechol moieties (highlighted in red) to form a hydrogel that can adhere to the insides of blood vessels.
Biological tests show that this material (highlighted in green in the histological micrograph above) withstands physiological levels of shear stress and remains implanted in mice for up to four months. The substance could provide a new way of protecting inflamed arteries against damage and the formation of blood clots that can cause heart attacks and strokes.
By Tyler Irving
Posted March 2013
An international team led by a researcher from the University of British Columbia has designed a new hydrogel based treatment for damaged blood vessels. The material used was inspired by the amino acid ‘glue’ that holds marine mussels to rocks.
In blood vessels, atherosclerotic plaques — caused by accumulation of fatty materials — are covered in a thin layer of endothelial cells. If this breaks, the contact between the blood and the fatty material underneath can cause clots, which may eventually lead to heart attacks or strokes. “We’re coating over the plaque, making a barrier between the blood and the diseased part of the vessel,” says Christian Kastrup, assistant professor at UBC’s Michael Smith Laboratories in the department of biochemistry and molecular biology. The goal of the technique, the subject of a recently published paper in Proceedings of the National Academy of Sciences, is to increase the integrity of the vessel and prevent the need for more drastic and potentially damaging procedures like stents or angioplasty.
To do this, the team needed a material that would be adhesive under water with strong shear conditions. “If mussels can adhere to surfaces with waves crashing over them, they could probably adhere to those with blood flowing over them as well,” says Kastrup. The active ingredients in mussel ‘glue’ are amino acids that contain chemical moieties called catechols. The team incorporated catechols into the alginate macromolecules that make up their hydrogel. Using a microfluidic model of a blood vessel, the team showed that the hydrogel stuck to endothelial cells at shear stresses ten times those experienced in the body. Other mechanical tests showed adhesion at even higher shear stresses: up to a thousand times physiological levels. Experiments in mice showed that the gels remained in place four months following implantation.
Future studies will focus on optimizing the system for larger blood vessels, however Kastrup doesn’t expect to see application in humans for at least five years. “From a technology standpoint I think we’ve overcome the major challenges, but it will take a long time to verify what we see in this non-human model,” he says.
Photo credit: Christian J. Kastrup
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