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12,943 result(s) for "Cryopreservation"
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Cancer and fertility preservation: international recommendations from an expert meeting
In the last years, thanks to the improvement in the prognosis of cancer patients, a growing attention has been given to the fertility issues. International guidelines on fertility preservation in cancer patients recommend that physicians discuss, as early as possible, with all patients of reproductive age their risk of infertility from the disease and/or treatment and their interest in having children after cancer, and help with informed fertility preservation decisions. As recommended by the American Society of Clinical Oncology and the European Society for Medical Oncology, sperm cryopreservation and embryo/oocyte cryopreservation are standard strategies for fertility preservations in male and female patients, respectively; other strategies (e.g. pharmacological protection of the gonads and gonadal tissue cryopreservation) are considered experimental techniques. However, since then, new data have become available, and several issues in this field are still controversial and should be addressed by both patients and their treating physicians.In April 2015, physicians with expertise in the field of fertility preservation in cancer patients from several European countries were invited in Genova (Italy) to participate in a workshop on the topic of \"cancer and fertility preservation\". A total of ten controversial issues were discussed at the conference. Experts were asked to present an up-to-date review of the literature published on these topics and the presentation of own unpublished data was encouraged. On the basis of the data presented, as well as the expertise of the invited speakers, a total of ten recommendations were discussed and prepared with the aim to help physicians in counseling their young patients interested in fertility preservation.Although there is a great interest in this field, due to the lack of large prospective cohort studies and randomized trials on these topics, the level of evidence is not higher than 3 for most of the recommendations highlighting the need of further research efforts in many areas of this field. The participation to the ongoing registries and prospective studies is crucial to acquire more robust information in order to provide evidence-based recommendations.
Advances in the Treatment and Prevention of Chemotherapy-Induced Ovarian Toxicity
Due to improvements in chemotherapeutic agents, cancer treatment efficacy and cancer patient survival rates have greatly improved, but unfortunately gonadal damage remains a major complication. Gonadotoxic chemotherapy, including alkylating agents during reproductive age, can lead to iatrogenic premature ovarian insufficiency (POI), and loss of fertility. In recent years, the demand for fertility preservation has increased dramatically among female cancer patients. Currently, embryo and oocyte cryopreservation are the only established options for fertility preservation in women. However, there is growing evidence for other experimental techniques including ovarian tissue cryopreservation, oocyte in vitro maturation, artificial ovaries, stem cell technologies, and ovarian suppression. To prevent fertility loss in women with cancer, individualized fertility preservation options including established and experimental techniques that take into consideration the patient's age, marital status, chemotherapy regimen, and the possibility of treatment delay should be provided. In addition, effective multidisciplinary oncofertility strategies that involve a highly skilled and experienced oncofertility team consisting of medical oncologists, gynecologists, reproductive biologists, surgical oncologists, patient care coordinators, and research scientists are necessary to provide cancer patients with high-quality care.
Oocyte cryopreservation review: outcomes of medical oocyte cryopreservation and planned oocyte cryopreservation
The utilization of oocyte cryopreservation (OC) has become popularized with increasing numbers of reproductive-aged patients desiring to maintain fertility for future family building. OC was initially used for fertility preservation in postmenarchal patients prior to gonadotoxic therapies; however, it is now available to patients to circumvent age-related infertility and other diagnoses associated with early loss of ovarian reserve. The primary aim of this paper is to provide a narrative review of the most recent and robust data on the utilization and outcomes of OC in both patient populations. OC results in similar oocyte yield in patients facing gonadotoxic therapies and patients undergoing planned OC. Available data are insufficient to predict the live birth rates or the number of oocytes needed to result in live birth. However, oocyte yield and live birth rates are best among patients < 37.5 years old or with anti-mullerian hormone levels > 1.995 ng/dL, at the time of oocyte retrieval. There is a high 'no use' rate (58.9%) in patients using planned OC with 62.5% returning to use frozen oocytes with a spouse. The utilization rate in medical OC patients is < 10%. There is currently no data on the effects of BMI, smoking, or ethnicity on planned OC outcomes. It is too early to draw any final conclusions on outcomes of OC in medical OC and planned OC; however, preliminary data supports that utilization of OC in both groups result in preservation of fertility and subsequent live births in patients who return to use their cryopreserved eggs. Higher oocyte yield, with fewer ovarian stimulation cycles, and higher live birth rates are seen in patients who seek OC at younger ages, reinforcing the importance of age on fertility preservation. More studies are needed in medical OC and planned OC to help guide counseling and decision-making in patients seeking these services.
Female Fertility: Is it Safe to Freeze
Objective: To evaluate the safety and risk of cryopreservation in female fertility preservation. Data sources: The data analyzed in this review were the English articles from 1980 to 2013 from journal databases, primarily PubMed and Google scholar. The criteria used in the literature search show as tbllowing: ( 1 ) human; embryo; cryopreservation/freezing/vitrification, (2) human; oocyte/immature oocyte; cryopreservation/freezing/vitrification, (3) human; ovarian tissue transplantation; cryopreservation/ freezing/vitrification, (4) human; aneuploidy/DNA damage/epigenetic; cryopreservation/freezing/vitrification, and (5) human; fertility preservation; maternal age. Study selection: The risk ratios based on survival rate, maturation rate, fertilization rate, cleavage rate, implantation rate. pregnancy rate. and clinical risk rate were acquired from relevant meta-analysis studies. These studies included randomized controlled trials or studies with one of tile primary outcome measures covering cryopreservation of human mature oocytes, embryos, and ovarian tissues within the last 7 years (from 2006 to 2013. since the pregnancy rates of oocyte vitrification were significantly increased due to the improved techniques). The data involving immature oocyte cryopreservation obtained from individual studies was also reviewed by the at, thors. Results: Vitrifications of mature oocytes and embryos obtained better clinical outcomes and did not increase the risks of DNA damage, spindle configuration, embryonic aneuploidy, and genomic imprinting as compared with fresh and slow-freezing procedures, respectively. Conclusions: Both embryo and oocyte vitrifications are safe applications in female fertility preservation.
Investigation of the optimal culture time for warmed bovine ovarian tissues before transplantation
Ovarian tissue cryopreservation by vitrification is an effective technique, but there are still many unresolved issues related to the procedure. The aim of this study was to investigate the optimal culture time of postwarmed ovarian tissues and their viability before ovarian tissue transplantation. The bovine ovarian tissues were used to evaluate the effect of postwarming culture periods (0, 0.25, 0.5, 1, 2, 5, and 24 h) in the levels of residual cryoprotectant, LDH release, ROS generation, gene and protein abundance, and follicle viability and its mitochondrial membrane potential. Residual cryoprotectant concentration decreased significantly after 1 h of culture. The warmed ovarian tissues that underwent between 0 and 2 h of culture time showed similar LDH and ROS levels compared with fresh nonfrozen tissues. The anti-Mullerian hormone transcript abundance did not differ in any of the groups. No increase in the relative transcript abundance and protein level of Caspase 3 and Cleaved-Caspase 3, respectively, in the first 2 h of culture after warming. On the other hand, an increased protein level of double stranded DNA breaks (gamma-H2AX) was observed in postwarmed tissues disregarding the length of culture time, and a temporary reduction in pan-AKT was detected in postwarming tissues between 0 and 0.25 h of culture time. Prolonged culture time lowered the percentage of viable follicles in warmed tissues, but it did not seem to affect the follicular mitochondrial membrane potential. In conclusion, 1–2 h of culture time would be optimal for vitrified-warmed tissues before transplantation. Summary Sentence For ovarian tissue cryopreservation by vitrification, the recommended culture time following warming is between 1 and 2 h before ovarian tissue transplantation. Graphical Abstract
Nanoparticle‐Mediated Intracellular Protection of Natural Killer Cells Avoids Cryoinjury and Retains Potent Antitumor Functions
The ability of natural killer (NK) cells to mediate potent antitumor immunity in clinical adoptive transfer settings relies, in large part, on their ability to retain cytotoxic function following cryopreservation. To avoid potential systemic toxicities associated with infusions of NK cells into patients in the presence of dimethylsulfoxide (DMSO), interest in alternative cryoprotective agents (CPAs) with improved safety profiles has grown. Despite the development of various sugars, amino acids, polyols, and polyampholytes as cryoprotectants, their ability to promote protection from intracellular cryodamage is limited because they mostly act outside of the cell. Though ways to shuttle cryoprotectants intracellularly exist, NK cells' high aversity to manipulation and freezing has meant they are highly understudied as targets for the development of new cryopreservation approaches. Here, the first example of a safe and efficient platform for the intracellular delivery of non‐DMSO CPAs to NK cells is presented. Biocompatible chitosan‐based nanoparticles are engineered to mediate the efficient DMSO‐free cryopreservation of NK cells. NK cells cryopreserved in this way retain potent cytotoxic, degranulation, and cytokine production functions against tumor targets. This not only represents the first example of delivering nanoparticles to NK cells, but illustrates the clinical potential in manufacturing safer allogeneic adoptive immunotherapies “off the shelf.” The clinical use of natural killer (NK) cells in immunotherapy requires cryopreservation prior to administration to patients. The process of cryopreservation, however, damages NK cells and, when DMSO is used, risks severe toxicities. Here, the development of a safe new nanoparticle‐based approach is described for the intracellular cryoprotection of NK cells, which yields functional effectors post cryopreservation devoid of DMSO.
CREATION OF THE OPTIMAL MEDIA FOR PLACENTAL TISSUE EXPLANTS CRYOPRESERVATION
Phase transitions and vitrification of multicomponent cryoprotective media including NaCl, dimethyl sulfoxide, sucrose, polyvinylpyrrolidone, dextran and hydroxyethylic starch for cryopreservation of explants of placental tissue as well as its morphological integrity after cryopreservation in these media with the aim of adequate selection of the components were studied by differential scanning calorimetry. Analysis of the obtained thermograms has shown that in all multicomponent cryoprotective media, frozen with a high rate, the part of the solution transforms into a vitrified state during warming ice crystallization from amorphous phase and melting of solution area with eutectic composition are absent. Minimal intensity of endothermal effect of ice melting as well as the highest morphological integrity of placental tissue is observed in multicomponent solutions containing 5% dimethyl sulfoxide and 6,8% sucrose or 5% hydroxyethylic starch in physiological solution. These media should be considered as optimal ones for cryopreservation of placental tissue explants, and their composition is recommended to be used when designing complex cryoprotective media.
A Chemically Defined Medium for Rabbit Embryo Cryopreservation. e71547
This study evaluates a new synthetic substitute (CRYO3, Ref. 5617, Stem Alpha, France) for animal-based products in rabbit embryo cryopreservation solutions. This evaluation was performed using two approaches: a thermodynamic approach using differential scanning calorimetry and a biological approach using rabbit embryo slow-freezing. During the experiment, foetal calf serum (FCS) was used as a reference. Because FCS varies widely by supplier, three different FCS were selected for the thermodynamic approach. The rabbit embryo slow-freezing solutions were made from Dulbecco's phosphate buffer saline containing 1.5 M Dimethyl Sulfoxide and 18% (v.v-1) of CRYO3 or 18% (v.v-1) of FCS. These solutions were evaluated using four characteristics: the end of melting temperature, the enthalpy of crystallisation (thermodynamic approach) and the embryo survival rates after culture and embryo transfer (biological approach). In the thermodynamic approach, the solutions containing one of the three different FCS had similar mean thermodynamic characteristics but had different variabilities in the overall data with aberrant values. The solution containing CRYO3 had similar thermodynamic properties when compared to those containing FCS. Moreover, no aberrant value was measured in the solution containing CRYO3. This solution appears to be more stable than the solutions containing a FCS. In the biological approach, the in vitro embryo survival rates obtained with the solution containing CRYO3 (73.7% and 81.3%) and with the solution containing a FCS (77.6% and 71.9%) were similar (p = 0.7). Nevertheless, during the in vivo evaluation, the implantation rate (21.8%) and the live-foetuses rate (18.8%) of the CRYO3 group were significantly higher than the implantation rate (7.1%, p = 0.0002) and the live-foetuses rate (5.3%, p = 0.0002) of the FCS group. The pregnancy rate was also higher in the CRYO3 group compared to the FCS group (81.3% and 43.8%, respectively, p = 0.066). We conclude that CRYO3 can be used as a chemically defined substitute for animal-based products in rabbit embryo cryopreservation solutions.
Green tea extract as a cryoprotectant additive to preserve the motility and DNA integrity of human spermatozoa
Cryopreservation impairs sperm quality and functions, including motility and DNA integrity. Antioxidant additives in sperm freezing media have previously brought improvements in postthawed sperm quality. Green tea extract (GTE) is widely considered as an excellent antioxidant, and its beneficial role has been proven in other human cells. This study aims to evaluate the GTE as a potential additive in cryopreservation media of human spermatozoa. In part one, the semen of 20 normozoospermic men was used to optimize the concentration of GTE that maintains sperm motility and DNA integrity against oxidative stress, induced by hydrogen peroxide (H2O2). Spermatozoa were treated with GTE at different concentrations before incubation with H2O2. In part two, the semen of 45 patients was cryopreserved with or without 1.0 ng ml−1 GTE. After 2 weeks, the semen was thawed, and the effect on sperm motility and DNA fragmentation was observed. Our data showed that GTE significantly protected sperm motility and DNA integrity against oxidative stress induced by H2O2when added at a final concentration of 1.0 ng ml−1. We found that the addition of 1.0 ng ml−1 GTE to cryopreservation media significantly increased sperm motility and DNA integrity (both P < 0.05). More interestingly, patients with high sperm DNA damage benefited similarly from the GTE supplementation. However, there was no significant change in the reactive oxygen species (ROS) level. In conclusion, supplementing sperm freezing media with GTE has a significant protective effect on human sperm motility and DNA integrity, which may be of clinical interest.