Trachea-constructor
The trachea of an adult consists of 18-22 cartilaginous rings, covered from the inside with a mucous membrane that moisturizes and cleanses the inhaled air.
Tracheal stenosis is the outcome of many injuries and diseases, manifested in narrowing of the lumen and difficulty breathing. Treatment tactics depend on the degree of stenosis, in severe cases surgical excision of the narrowed trachea is necessary. The relevant question is: how to close the defect after such an operation?
Currently, there are no artificial or natural materials suitable for the long-term treatment of major tracheal defects.
For a successful tracheal transplant, the graft must have elastic walls to avoid sticking together. In addition, it should be lined from the inside with ciliated epithelium, which would perform the functions of the mucous membrane of the natural trachea and would not be attacked by the immune system of the recipient's body. It is critically important that the body's vessels entwine the graft and provide respiration and nutrition of tracheal cells.
A group of researchers from Western Reserve University Case in Cleveland (USA) under the leadership of Eben Alsberg (Eben Alsberg) has developed a way to create a viable artificial trachea.
They used biopolymer microspheres to deliver cartilage growth factors to adult human mesenchymal stem cells. The interaction of growth factors with stem cells led to the controlled growth of cartilage rings. The diameter, thickness and mechanical parameters of the rings can be adjusted.
To form the mucous membrane of the trachea, the researchers used cells of the ciliated epithelium of the bronchi.
After transplantation, nutrition and respiration of the transplant cells are necessary. This is possible only in the case of the formation of microcirculation – a dense network of capillaries entwining cells. The researchers cultured human umbilical vein endothelial cells with mesenchymal stem cells. As a result, vascular precursors were obtained.
The scheme of the artificial trachea: l – cartilaginous ring, ll – cartilaginous ring with epithelium, lll – cartilaginous ring with epithelium and vascular precursors.
The trachea, like a constructor, is assembled from links, each of which is a cartilaginous ring lined with ciliated epithelium, with vascular precursors.
It should be noted that the cartilage artificially grown from stem cells is comparable, and in some respects surpassed the natural tissue in strength and mechanical properties.
The researchers transplanted a fragment of an artificially grown trachea under the skin of mice. The vessels of the body after transplantation began to form anastomoses with the vessels of the trachea, thus the blood supply to the transplant began.
The creation of an organ that is able to integrate with the recipient's body gives hope for the cure of a number of tracheal diseases. In addition, the described method, after modification, can be used to create other hollow organs, for example, the esophagus, intestines or ureter.
Article by A. D. Dikina et al. A Modular Strategy to Engineer Complex Tissues and Organs is published in the journal Advanced Science.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru .