A 3D-printed, microporous scaffold that supports the development of mouse follicle cells (egg-producing cells found in ovaries) and can be used to restore ovary function in surgically sterilised mice is described in Nature Communications this week. The microporous scaffolds support follicle cell development much better than previous scaffolds, although the same materials have been used in different designs and the successful transplantation of follicle cells has already been shown in mice. However, this study represents an advance for the field of fertility preservation by being the first reported functional ovarian implant in mice designed using 3D printing.
There is a clinical need to develop an ovary transplant that can effectively restore fertility and hormones in oncofertility patients - individuals with diminished ovary function due to cancer treatment. Isolated follicles can be used to create an engineered bioprosthetic ovary, but these cells need to be held in a 3D environment to maintain normal cell-to-cell interactions. Previous studies have shown that hydrogel scaffolds provide a suitable environment, and have demonstrated live births from resulting bioprosthetic ovaries transplanted in mice.
Ramile Shah and colleagues build on this research, tweaking the design of the scaffold to alter the architecture in terms of pore structure, which alters how the follicle and scaffold interact. They demonstrate that as scaffold interaction increases, follicle spreading is limited and survival increases. As seen in previous studies, the authors show that transplantation of these bioprosthetic ovaries into surgically sterilised mice restores fertility, and resulted in the birth of healthy litters of mouse pups.
Although physiologically sufficient to enable pregnancy, the efficiency of ovarian restoration is low and the method is only applicable to mice. This microporous scaffold cannot readily be applied to human follicles, which are much larger so the structure and pore size of the scaffold would need to be altered substantially. Furthermore, as human follicles grow rapidly to a much larger size, it is unclear if such a scaffold approach would indeed support human follicle survival on implantation.