New Approach to the Cryopreservation of GV Oocytes and Cumulus Cells through the Lens of Preserving the Intercellular Gap Junctions Based on the Bovine Model.

Differences in structural and functional properties between oocytes and cumulus cells (CCs) may cause low vitrification efficiency for cumulus-oocyte complexes (COCs). We have suggested that the disconnection of CCs and oocytes in order to further cryopreservation in various ways will positively affect the viability after thawing, while further co-culture in vitro will contribute to the restoration of lost intercellular gap junctions. This study aimed to determine the optimal method of cryopreservation of the suspension of CCs to mature GV oocytes in vitro and to determine the level of mRNA expression of the genes (, ; , ) and gene-specific epigenetic marks () after cryopreservation and in vitro maturation (IVM) in various culture systems.

Technology for Biobanking of Epididymal Spermatozoa from Patient with Obstructive Azoospermia: Case Report about Baby Born after Conventional Freezing Only with a Nonpermeable Cryoprotectant 360 kDa Polyvinylpyrrolidone.

This publication reports, for the first time, the birth of a healthy child after intracytoplasmic sperm injection (ICSI) of motile spermatozoa after conventional ("slow") freezing of epididymal spermatozoa using 5% polyvinylpyrrolidone (PVP) of high molecular weight (360 kDa). Cryopreservation solution with 10% PVP was added to 30 µL of spermatozoa suspension in a 1:1 ratio, with a final PVP concentration of 5%. Then, polycarbonate capillaries for oocyte denudation with a diameter of 170 µm were filled with 60 µL of the resulting sperm suspension.

State of the art in assisted reproductive technologies for patients with advanced maternal age.

According to the World Health Organization, the female reproductive age lasts up to 49 years, but problems with the realization of women's reproductive rights may arise much earlier. Significant numbers of factors affect the state of reproductive health: socioeconomic, ecological, lifestyle features, the level of medical literacy, and the state of the organization and medical care quality. Among the reasons for fertility decline in advanced reproductive age are the loss of cellular receptors for gonadotropins, an increase in the threshold of sensitivity of the hypothalamic-pituitary system to the action of hormones and their metabolites, and many others.

Using Dextran Instead of Egg Yolk in Extender for Cryopreservation of Spermatozoa of Dogs of Different Ages.

Egg yolk is a very common supplement of extenders aimed to protect sperm from cryoinjury, but due to their biological risks and difficulties with media standardization, there is a search for alternative. In addition, sperm cryoresistance can be affected by the initial decrease of their functional characteristics caused by age. The aim of this work was to evaluate the efficiency of using dextran (molecular weight 500 kDa) in the extenders instead of egg yolk for the cryopreservation of spermatozoa of dogs (Chinese Crested breed) of different ages.

Embryological Characteristics and Preimplantation Genetic Testing for Aneuploidy of Embryos Derived from Cryopreserved Oocytes of Women of Different Reproductive Ages.

Oocyte vitrification is widely used for female fertility preservation. However, the efficacy of this procedure may depend on the women's age. The aim of the study was to compare the morphology, viability of cryopreserved oocytes, and their fertilization outcomes (fertilization, blastulation rate, level of embryo chromosomal aneuploidy-preimplantation genetic testing for aneuploidy [PGT-A]) in women of different reproductive ages.

New method for cryoprotectant-free freezing of human oligoasthenoteratozoospremic spermatozoa with high-molecular polymer.

Data about cryoprotectant-free cryopreservation of human ICSI spermatozoa are limited. The aim of this investigation was to compare two technologies for cryopreservation of spermatozoa from men with oligoasthenoteratozoospermia: standard conventional freezing with 5% glycerol (freezing in glycerol) and cryoprotectant-free freezing with 5% high-molecular-weight (360 kDa) polyvinylpyrrolidone (PVP) (PVP-freezing). Capillaries with spermatozoa were cooled in vapor and then plunginged into liquid nitrogen.

The impact of cryopreservation on the morphology of spermatozoa in men with oligoasthenoteratozoospermia.

The cryopreservation of ejaculate can reduce the viability, motility, and morphological characteristics of the spermatozoa of infertile men. Oligoasthenoteratozoospermia (OAT) is the most common cause of male subfertility. The aim of this study was to evaluate the morphological characteristics and viability of progressive motile sperm fraction before and after cryopreservation, and to determine whether cryopreservation of progressive motile sperm fraction is effective in eliminating morphologically abnormal sperm in men with OAT.

Does human oocyte cryopreservation affect equally on embryo chromosome aneuploidy?

Oocytes cryopreservation as an important part of assisted reproductive technologies, which should ensure after warming not only intact oocyte morphological characteristics, but also their genetic apparatus stability. However, the meiotic spindle is very sensitive to the temperature fluctuations that can lead to unequal chromosome segregation during meiosis and as a consequence can cause embryo aneuploidy after oocyte fertilization. The aim of the study was to estimate the oocytes cryopreservation impact on human embryo chromosome aneuploidy.

Cryopreservation of incomplete compacted morulae and preliminary biopsy of excluded fragments.

The complexity of predicting embryo development potential at the cleavage stages and the emergence of epigenetic risks during prolonged in vitro culture of pre-implantation embryos made it more advantageous to transfer embryos at the morula stage to the uterine cavity. The criteria for estimating embryos at this stage that allow prediction of cryopreservation outcomes have been poorly described. All day 4 embryos (n = 224) were graded 1, 2, 3, 4 or 5 according to blastomere compaction degree (BCD = 100, 75, 50, 25 or 0%, respectively) and the survival and blastocyst formation rate of these morulae were studied after cryopreservation.

Science of cryopreservation in reproductive medicine - Embryos and oocytes as exemplars.

The modern successes of reproductive medicine are based on the achievements in the fields of artificial fertilization and cryobiology over the last 50years. Cryopreservation of oocytes makes it possible to preserve their reproductive potential after surgical interventions, treatment of cancer, for delayed pregnancy and to use cells for donation. Cryopreservation of embryos allows not only to reduce the multiple pregnancies rate and to increase the cumulative pregnancy rate as a result of embryo transfer in the following favorable cycles of the patient, but is also a necessary procedure in case of genetic diagnosis or in the case of contraindications for embryo transfer in the stimulated cycle due to possible complications.