Vitreous Cryopreservation of Human Preantral Follicles Encapsulated in Alginate Beads with Mini Mesh Cups

Abstract

To completely avoid ice crystal formation and thus get a higher survival rate, vitrification methods have been commonly used for cryopreservation of oocytes and embryos. However, currently used vitrification methods for oocytes and embryos are not suitable for the cryopreservation of preantral follicles (PFs). In the present study, stainless steel mesh was fabricated into mini mesh cups to vitrify isolated PFs. Moreover, isolated follicles were encapsulated and then subjected to vitreous cryopreservation to facilitate in vitro culture/maturation of follicles after warming. The results showed that the percentages of viable follicles did not differ significantly between the vitrification group and fresh group soon after warming (81.25% vs. 85.29%, P>0.05) and after a 7-day culture period (77.78% vs. 83.33%, P>0.05). No difference in mean follicular diameter was observed between cryopreserved and fresh follicles when cultured in vitro. Transmission electron microscopic analysis revealed that vitreous cryopreservation could maintain the ultrastructure of follicles in alginate beads. In conclusion, the present vitrification method could efficiently cryopreserve isolated human ovarian follicles encapsulated by calcium alginate, which could be put into immediate use (in vitro culture/ maturation) after warming. However, more follicles and some detailed biochemical analyses are required to further investigate the effects of vitrification on the long-term growth of human encapsulated PFs.

Vitrified sheep isolated secondary follicles are able to grow and form antrum after a short period of in vitro culture

“…In mice, isolated preantral follicles vitrified and treated with propidium iodide (PI) showed a decrease of 11 % in their viability (Trapphoff et al 2010). The viability of isolated follicles vitrified and in vitro-cultured found in our study was similar to that reported for human follicles (Bian et al 2013). In Follicle-Vit, the proportion of viable follicles decreased with time in culture compared to fresh follicles.…”

“…Our data show that secondary follicles from Follicle-Vit had diameter and daily growth rate in vitro similar to those seen in non-vitrified, cultured follicles, similar to the results reported for human follicles (Bian et al 2013). On the other hand, follicles from Tissue-Vit had slower growth compared to cultured follicles not subjected to prior vitrification.…”

“…Lowercase letters indicate statistically significant differences (P<0.05) between days of culture These structures develop with zona pellucida during growth of the secondary follicle, allowing the exchange of metabolites essential for the development of oocyte competence (Lucci et al 2001;Duarte et al 2012). Vitrification can cause profound ultrastructural changes in these microvilli (Fuku et al 1995), especially when the vitrified follicle is further subjected to in vitro culture, even for a short period (Bian et al 2013).…”

In vitro development of human primordial follicles to preantral stage after vitrification

“…Vitrification is a relatively inexpensive procedure and does not require any special instrument [10]. Ovarian tissue vitrification has been performed in mice [11][12][13], domestic animals [14][15][16][17], nonhuman primates [18][19][20], and in humans [21][22][23][24]. To date, no pregnancy has been reported in humans after transplantation of vitrified tissue [3].…”

The relationship between the inflammatory response and cell adhesion on alginate-chitosan-alginate microcapsules after transplantation

“…At present, cell microencapsulation technology is considered to be a viable therapy. Microencapsulated somatic cells can be used to treat neurological and endocrine diseases, such as diabetes, syndromes after the removal of ovaries, and Parkinson's disease . Microencapsulated stem cells can aid bone regeneration and growth plate injury, repair the myocardium and improve angiogenesis .…”