Researchers from the Columbia University Irving Medical Center have developed a tissue engineering and 3D printing method to grow new hair follicles and stop hair loss. Their work, recently published in Nature Communications, demonstrates that they were able to grow human hair follicles in a dish and on mice for the first time. These hair follicles could be used to address hair thinning and pattern baldness that affects millions of Americans.
This innovation arises, in part, due to recent advances in 3D printing that enabled the researchers to create a unique patterning device. The printed device has long extensions that are half a millimeter wide and have an aspect ratio of 100:1. Previous 3D-printing methods were unable to create these thin projections, which were critical to the development of this new human skin construct.
Mouse and rat hair cells can easily develop into mature hair follicles with hair in a dish and when implanted in mice. Yet, human hair cells have been substantially more difficult to work with and had previously not been able to be cultured in a dish or in animal models. To address this, the researchers investigated new approaches to grow human hair follicles and skin constructs.
The researchers created the human skin construct by patterning collagen and human fibroblasts to form a thin gel. Then, they use a 3D-printed device with long, narrow spokes, to pattern deep, narrow wells into the collagen gel. Then, the dendritic progenitor cells, which develop into hair follicles, are seeded in the wells and supplemented with a cocktail of bioactive factors to help them develop into mature hair follicles.
The researchers tested the skin constructs by implanting them into immunodeficient, nude mice. After 4-6 weeks, they observed hair growth from the constructs. They noted the hair structure from their engineered tissue was similar to human hair, and that on a biological level, there were also many similarities.
“What we’ve shown is that we can basically create a hair farm: a grid of hairs that are patterned correctly and engineered so they can be transplanted back into that same patient’s scalp,” said Angela Christiano, PhD, the lead researcher of the study. “That expands the availability of hair restoration to all patients—including the 30 million women in the United States who experience hair thinning and young men whose hairlines are still receding. Hair restoration surgery would no longer be limited by the number of donor hairs.”
The publication in Nature Communications: Tissue engineering of human hair follicles using a biomimetic developmental approach