According to Shah, the key to the success of the project was the hydrogel used to create the scaffold for the 3D printed organ. It was a challenge to find the right material – the researchers had to create something that was rigid enough to hold its form during implantation but porous enough to interact naturally with the mouse’s system once it was implanted. The solution came in the form of a gelatin seeded with immature eggs.
“Most hydrogels are very weak, since they’re made up of mostly water, and will often collapse on themselves,” Shah said. “But we found a gelatin temperature that allows it to be self-supporting, not collapse, and lead to building multiple layers. No one else has been able to print gelatin with such well-defined and self-supported geometry.”
“This is the first study that demonstrates that scaffold architecture makes a difference in follicle survival,” Shah said. “We wouldn’t be able to do that if we didn’t use a 3-D printer platform.”
The study was undertaken in hopes of one day restoring fertility to female cancer patients whose treatment, whether in childhood or adulthood, had rendered them infertile or with lowered fertility. The natural ovary was removed from a mouse and replaced with the 3D printed one. Once it was implanted, it was able to ovulate like a biological ovary, and once the mouse was mated, she became pregnant and gave birth to healthy baby mice, which are called pups. The mother was even able to lactate and nurse her babies.
“What happens with some of our cancer patients is that their ovaries don’t function at a high enough level and they need to use hormone replacement therapies in order to trigger puberty,” said Monica Laronda, co-lead author of the study. “The purpose of this scaffold is to recapitulate how an ovary would function. We’re thinking big picture, meaning every stage of the girl’s life, so puberty through adulthood to a natural menopause.”
“This research shows these bioprosthetic ovaries have long-term, durable function,” said Woodruff. “Using bioengineering, instead of transplanting from a cadaver, to create organ structures that function and restore the health of that tissue for that person, is the holy grail of bioengineering for regenerative medicine.”
The research has been published in a paper entitled “A bioprosthetic ovary created using 3D printed microporous scaffolds restores ovarian function in sterilized mice,” which you can read here. Authors include Monica M. Laronda, Alexandra L. Rutz, Shuo Xiao, Kelly A. Whelan, Francesca E. Duncan, Eric W. Roth, Teresa K. Woodruff and Ramille N. Shah. Discuss in the 3D Printed Ovary forum at 3DPB.com.
[Source: Northwestern University]