Boiling histotripsy
Ultrasound for creating fabric frames
Researchers from the University of Washington have developed a unique method of using ultrasound waves to create cell scaffolds for tissue engineering, which can help overcome one of the main obstacles standing in the way of regenerative medicine.
The emergence of a new method was made possible by a happy accident. The researchers studied the possibilities of using boiling histotripsy, a technique that uses millisecond pulses of high–intensity ultrasound waves to destroy tissue, to remove malignant tumors by diluting them with ultrasound. It was assumed that after the destruction of tumors, the body should get rid of their remnants as cellular debris. However, when analyzing tissues decellularized (cleared of cells) using this method, scientists made an unexpected finding: it turned out that boiling histotripsy does not destroy the fibrous components of stromal tissue and blood vessels.
The structure remaining after tissue decellularization is known as the extracellular (extracellular) matrix and is a fibrous framework on which cells grow. Most decellularization methods involve prolonged chemical or enzymatic treatment, usually damaging tissues and fibers. Histotripsy, on the contrary, provides rapid decellularization of tissue with minimal damage to the matrix.
After studying the structure remaining after boiling histotripsy, the researchers came to the conclusion that it is an almost ideal framework for growing cells in tissue engineering and regenerative medicine. Firstly, such structures have already acted as a support for the cells forming this or that organ. Secondly, due to its composition, the extracellular matrix causes a relatively weak immune response when implanted into the donor's body.
A cross-section of the lesion formed in the cow liver tissue under the action of boiling histotripsy. After washing out the liquefied cellular components, the extracellular matrix was exposed. The scale size corresponds to 5 mm.
Theoretically, such a framework can be populated with the patient's own stem cells, which will allow to grow a new organ for transplantation. The authors also consider the possibility of implanting the extracellular matrix itself, which will later be populated by the body's own cells.
Currently, they are working on methods of decellularization of kidney and liver tissue of large animals, and in the future they plan to increase the size of the treated tissue fragments and evaluate the regenerative properties of the resulting skeletons in animal experiments.
Presentation by Yak-Nam Wang et al. Tissue decellularization with boiling histotripsy and the potential in regenerative medicine was presented at the 168th Congress of the American Acoustic Society, held on October 27-21 in Indianapolis.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the American Institute of Physics:
High-intensity Sound Waves May Aid Regenerative Medicine.
05.11.2014