Complex structures of artificial capillaries
Vessels for growth: control and observation
The development, first of all, opens up new opportunities for studying blood vessel diseases and ways to combat them – in particular, for testing new types of drugs. In general, the synthesis of completely artificial vessels or the cultivation of new "natural" ones has been developing rapidly in recent years, promising, in the end, a method for obtaining vessels suitable for transplantation to patients.
However, even against the background of previous successes, researchers from Professor Ying Zheng's group managed to achieve a unique result, not only by growing full–fledged "living" vessels in the laboratory, but also by learning how to control their growth and form complex structures from them - some interesting examples can be seen in the illustrations:
The authors grew the letters of their alma mater from the vessels
Artificial vessels can make turns at right angles and form T-shaped joints.
Staining allows you to see the nuclei of the cells of the vessel wall (blue), the connections between the cells (red),
as well as smooth muscle tissue cells (green)
The authors are confident that their methods will find application in the study of the most natural process of vascular formation – angiogenesis – as well as the development of diseases affecting the vascular system.
Microscopic capillaries "in vitro" behave exactly like in the human body: they form branches, react normally to vasoconstrictors, transporting blood even through sharp corners.
For the formation of vascular structure, the basis is a network of collagen strands – a very common protein that is part of ligaments, tendons, bone and cartilage tissue. Tiny tubules are formed in this collagen substrate, which are filled with cells of the endothelium, the tissue lining the vessels from the inside. Within two weeks, these cells grow and unite, forming tubular structures of blood vessels. The walls of the vessels of our body form not only endothelial cells, but also smooth muscles, and connective stromal cells. These latter were added to the system additionally.
"In such a system, we can isolate each component for detailed study or put them together to consider as a whole," says Ying Zheng, "We can separately consider biophysical, biochemical, cellular elements. How does the endothelium react to changes in blood flow velocity and exposure to different substances? How does it interact with other cells and how does this affect the permeability of the vessel walls? Now we have a lot of new opportunities to find out these details."
Interestingly, this approach can also be used to study the growth of malignant tumors: cancer cells, in fact, secrete signaling substances that stimulate the growth of a developed vascular system in the tumor, not only feeding it, but also spreading cancer cells throughout the body. This mechanism can now be reproduced "in vitro" in all details – perhaps cancer will be defeated not by assault, but by siege, having learned to deprive tumors of access to nutrients.
According to a University of Washington press release: Engineered microvessels provide a 3-D test bed for human diseases.
Portal "Eternal youth" http://vechnayamolodost.ru07.06.2012