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This is how the capillaries grow

Scientists from the Technion and the Weizmann Institute of Science showed how mechanical forces affect the development of blood vessels and their organization in a directional structure

An example of blood vessels with a well-defined directional order created in the laboratory after tensile forces were applied to them
An example of blood vessels with a well-defined directional order created in the laboratory after tensile forces were applied to them

 

Most of the cells in our body are in contact with the extracellular matrix (ECM) that surrounds them. Until recently, many scientists assumed that it was mainly a biochemical relationship, but in recent years it has become clear that mechanical interactions, for example the ability of cells to sense the properties of the texture and respond to them, play a significant role in the development of the cell and its function. In an article published these days in the scientific journal Nano Letters, scientists from the Technion and the Weizmann Institute of Science show exactly how mechanical forces affect the development of blood vessels in biological tissue. The research was led by doctoral student Shira Landau and Prof. Shulamit Levenberg from the Faculty of Biomedical Engineering at the Technion and doctoral student Avraham Muriel and Prof. Eran Buchbinder from the Department of Chemical and Biological Physics at the Weizmann Institute of Science, in collaboration with Dr. Ariel Livna, a former post-doctoral researcher in the Department of Molecular Cell Biology at the Institute Weizmann for science.

In a series of studies carried out in Prof. Levenberg's laboratory, the mechanical sensitivity of vascular networks was examined, that is, the effect of mechanical forces on the nature of these networks and the direction of their growth and development. The studies were carried out in a system developed in Prof. Levenberg's laboratory and which was designed to improve tissue creation processes for transplantation.

The creation of artificial tissues intended for transplantation is a significant tool in medical treatment. The scientific challenge is to produce the tissues so that they contain a network of blood vessels, which ensures a regular supply of oxygen and nutrients. Of great importance is the directional order of the network, that is, how well the blood vessels are organized in the same direction in space. These aspects are essential for the absorption of the graft and its survival. The technology developed by Prof. Levenberg is based on biodegradable XNUMXD polymeric scaffolds, on which biological cells are seeded which are essential for the development of blood vessels. The effectiveness of this technology has been demonstrated in a series of studies.

In 2016, Prof. Levenberg and Dr. Dekel Rosenfeld, who at the time was a doctoral student in her laboratory, published an article in the scientific journal "Records of the American Academy of Sciences" (PNAS), in which they presented an original stretching system that exerts on the artificial tissue forces that affect the biological processes in the cells and even On their differentiation, shape, migration and organization in structures - as well as on the geometry of the developing tissue, on its maturity and stability.

 

Different types of traction forces led to the appearance of a different directional order in the vascular networks: a vertical order for the dynamic-cyclic traction forces (right) or a parallel order for the static traction forces (left)
Different types of traction forces led to the appearance of a different directional order in the vascular networks: a vertical order for the dynamic-cyclic traction forces (right) or a parallel order for the static traction forces (left)

In the same study, it became clear that tensile forces acting on the tissues during their growth phase lead to the growth of blood vessels with a defined directionality. "We wanted to understand how this process works and how to control it," says Shira Landau. "Prof. Buchbinder and his partners from the Weizmann Institute of Science, developed a theory that explains the effects of mechanical forces on the single cell, and together we expanded it to the multicellular tissue level."

In the new study, the scientists understood how both dynamic-cyclic stretching and static stretching can lead to the development of directional order in networks of blood vessels, even though the biophysical mechanism underlying the two processes is fundamentally different. "A significant challenge we faced", says Avraham Muriel, "was understanding the relationship between the complex biological experiments and the physical theory". The research led to the establishment of a stretching protocol that enables the creation of optimal tissues, in which networks are stable, rich and have a well-defined directional order of blood vessels.

The scientists hope that these results and insights will advance the possibility of creating in the future tissues of vascular networks, with a structure and orientation that will allow their effective transplantation in patients who will need it.

One response

  1. Perhaps this will lead to the study of blood vessels that develop during cancer growth and how it can be disrupted...

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