3D printing of living skin, including blood vessels, achieved

The American research team sees this as an important step in the development of transplants that resemble natural skin.

Successful integration in a mouse model

An American research team has found a way to create living skin with blood vessels using 3D printing. The scientists see this as an important step in the development of transplants that resemble natural skin.

Pankai Karanade, head of the study and member of the Center for Biotechnology and Interdisciplinary Studies (CBIS), Rensselaer Polytechnic Institute, USA, commented on the background of the project: "All skin grafts available to date resemble complex patches at best. Although they accelerate wound healing, in the end, they simply fall off, since they never really integrate into the host cells."

Artificial cells communicate with host cells

One of the main problems with the integration of skin grafts has so far been the absence of a functioning vascular system. Karanade and his team have been working on this issue for many years. In order to integrate vascular systems into the artificial skin, the scientists joined forces with a team from the Yale School of Medicine, USA.

In the current study, the researchers focus on the combination of human endothelial cells and pericytes with animal collagen and other cell structures typically used for skin grafts. The cells communicate with each other and form a biologically-relevant vascular structure within a few weeks.

Biology "takes the upper hand"

Karanade explained the process as follows: "We were aware that biology is much more complex than the simple systems we model in the laboratory. We were pleased to discover that biology takes over by itself and approaches natural structures as soon as this complexity is approached.”

In the test, the skin grafts were transferred to a group of mice. The blood vessels of the printed skin communicated with the blood vessels of the mice. "This is extremely important because the transfer of blood and nutrients keeps the graft alive," explained Karanade.

The potential of 3D bioprinting

In order to test their invention on a clinical level, researchers are still working on donor cells using techniques such as CRISPR technology so that blood vessels can also integrate into humans. "We haven't quite gotten there yet, but we're definitely one step ahead," Karanade noted.

Deepak Vashisht, Director of CBIS, commented on the research results: "This development illustrates the potential of 3D bioprinting in precision medicine. Solutions can be tailored to patients and specific situations. This project is a great example of how developers are working to find solutions to human health puzzles".

Creating skin grafts suited for diabetic ulcers or pressure ulcers

According to Karanade, more work will be needed to treat burns patients, as the loss of nerves and vascular ends must be taken into account. However, the skin transplant that is being developed so far may take a significant step forward in the treatment of patients with diabetic ulcers or pressure ulcers.

Karanade explained: "Our skin transplants are perfectly suited for such patients. Ulcers usually occur in clearly visible parts of the body and can be treated with smaller pieces of skin. Wound healing often takes longer for diabetics, but the process could be in any case accelerated".

Baltazar T et al., 3D bioprinting of a vascularized and perfusable skin graft using human keratinocytes, (..). Tissue Engineering Part A 2019; DOI:10.1089/ten.TEA.2019.0201