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Increasing evidence indicates that assisted reproductive technologies (ARTs) disturb skewed sex-ratio and induce sex-dimorphic postnatal effects. Undoubtedly, the combination of multiple ovulation and embryo transfer (MOET) together with the use of vitrification technique (MOVET) is currently being used in breeding programs. However, since the first case of sex skewing reported in 1991, the accumulative and long-term transmission of skewed sex-ratio to future generations has not been thoroughly evaluated. Here we test as MOVET program induce a skewed sex ratio, and we consider skewed sex ratio transmission to future generations. To this end, we first evaluated the F1 generation, demonstrating that a MOVET program causes a severe imbalance skewed secondary sex ratio (SSR) towards male by 12%. This imbalanced persist after a second MOVET program (F2 generation), with an accumulative skewed SSR towards male by 25%. Finally, using a crossbred generation derived from crossing F1 males derived from a MOVET program with naturally-conceived (NC) females, we show that the imbalance skewed SRR persist. Bodyweight comparison between MOVET animals and NC counterparts revealed significant changes at birth, weaning and adulthood. However, there was a significant interaction between F2 MOVET animals and sex, demonstrating an apparent accumulative sex-dimorphic effect. At adulthood, MOVET derived males presented a lower body weight. In conclusion, we show that the MOVET program causes a direct, accumulative and long-term transmission of skewed SSR. • Vitrified procedure biases the secondary sex ratio in the rabbit. • Vitrified procedure biases the secondary sex ratio in a transmissible and cumulative form. • Vitrified procedure entails long-term bodyweight consequences. • Vitrified procedure induced a sex-dimorphic pattern at adulthood. [ABSTRACT FROM AUTHOR]

Kidney transplantation from deceased or living human donors has been limited by donor availability as opposed to the increasing demand, and by the risk of allograft loss rejection and immunosuppressive therapy toxicity. In recent years, xenotransplantation of developed kidney precursor cells has offered a novel solution for the unlimited supply of human donor organs. Specifically, transplantation of kidney precursors in adult hosts showed that intact embryonic kidneys underwent maturation, exhibiting functional properties, and averted humoural rejection post-transplantation from non-immunosuppressed hosts. Even if supply and demand could be balanced using xenotransplants or lab-grown organs from regenerative medicine, the future of these treatments would still be compromised by the ability to physically distribute the organs to patients in need and to produce these products in a way that allows adequate inventory control and quality assurance. Kidney precursors originating from fifteen-day old rabbit embryos were vitrified using Cryotop® as a device and VM3 as vitrification solution. After 3 months of storage in liquid nitrogen, 18 kidney precursors were transplanted into non-immunosuppressed adult hosts by laparoscopy surgery. Twenty-one days after allotransplantation, 9 new kidneys were recovered. All the new kidneys recovered exhibited significant growth and mature glomeruli. Having achieved these encouraging results, we report, for the first time, that it is possible to create a long-term biobank of kidney precursors as an unlimited source of organs for transplantation, facilitating the inventory control and distribution of organs. [ABSTRACT FROM AUTHOR]