PEG-fibrinogen hydrogels appear to have an advantage over alginate scaffolds for culturing human primordial follicles. Folliculogenesis is not increased in the presence of substances that enhance PIP3 production or with thin rather than thick sectioning.

Ovarian sample preparation with slow-freezing + the improvement protocol appears to yield better implantation outcomes than needle-immersed vitrification with/without the improvement protocol. The real quality of frozen tissue can be assessed only after grafting and not after thawing/warming.

The possibility of maturing human primordial follicles in vitro would assist fertility restoration without the danger of reseeding malignancies. Leukaemia inhibitory factor (LIF) and certain culture matrices may promote human follicular growth. The present study compared human primordial follicular growth on novel culture matrices, namely human recombinant vitronectin (hrVit), small intestine submucosa (SIS), alginate scaffolds and human recombinant virgin collagen bioengineered in tobacco plant lines (CollPlant). The frozen-thawed ovarian samples that were used had been obtained from girls or young women undergoing fertility preservation. In the first part of the study, 20 samples were cultured for 6 days on hrVit or SIS with basic culture medium alone or supplemented with one of two concentrations of LIF (10ngmL and 100ngmL), with and without LIF-neutralising antibody. In the second part of the study, 15 samples were cultured for 6 days on alginate scaffolds or CollPlant matrices with basic culture medium. Follicular development was assessed by follicular counts and classification, Ki67 immunohistochemistry and 17β-oestradiol and anti-Müllerian hormone measurements in spent media samples. Primordial follicular growth was not enhanced by LIF. Despite some significant differences among the four matrices, none appeared to have a clear advantage, apart from significantly more Ki67-stained follicles on alginate and CollPlant matrices. Further studies of other culture matrices and medium supplements are needed to obtain an optimal system.