Researchers looking for an alternative to uterus transplants successfully restored uterine structure and function in rabbits using bioengineered uterine tissue.
The research, published in Nature Biotechnology, showed that the engineered tissue developed native tissue-like structures and was able to support pregnancies leading to live births.
'The study shows that engineered uterine tissue is able to support normal pregnancies, and fetal development was normal,' said author Professor Anthony Atala from the Wake Forest Institute for Regenerative Medicine in North Carolina. 'With further development, this approach may provide a pathway to pregnancy for women with an abnormal uterus'.
In the study, 78 rabbits were randomly assigned to four different groups: groups one to three had most of their uterine tissue removed. Group four was a normal control group, where animals underwent a sham surgery but no tissue was removed.
In group one the excision was repaired with a synthetic polymer scaffold containing cells collected from the tissue that was removed; group two underwent repair with the polymer scaffold only; in group three no extra material was added and the remaining edges were stitched together.
The polymer scaffolds degraded after three months. At six months the group that had repair with the scaffold only developed a thin uterine wall, but the group that received the scaffold seeded with cells had developed native tissue-like structures including distinct endometrium and myometrium tissue layers, and were expressing progesterone and oestrogen hormone receptors. The excision-only group formed scar tissue.
The rabbits were mated naturally with fertile males six months after the procedures. Four out of ten rabbits from the tissue-engineered group had normal pregnancies and gave birth to healthy offspring with normal body weights. No fetal development occurred in the scaffold-only or excision-only groups.
'This is a highly significant finding with great potential for future human application. For women who suffer infertility due to a severely damaged uterus or because of a hysterectomy then adaptations of this approach may well find clinical application,' said Professor Darren Griffin from the University of Kent, who was not involved in the study.
Uterus transplantation became a viable treatment following the first successful transplant which led to a live birth in 2014. However, this treatment is associated with a range of issues including lack of donors, transplant rejection and the risk of disease transmission. Bioengineered uteri could be an alternative treatment method for women with uterine infertility; however, more preclinical studies need to be carried out before clinical trials can be performed in humans.