Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia(OA)and nonobstructive azoospermia(NOA).For men with NOA,testicular sperm extraction(TESE)is the onl...Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia(OA)and nonobstructive azoospermia(NOA).For men with NOA,testicular sperm extraction(TESE)is the only method to obtain sperm for assisted reproductive technology(ART).Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts,cryopreservation of microdissection-TESE-obtained sperm is essential.Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts.After first delving into the physiological and molecular aspects of sperm cryopreservation,this review aims to examine the current methods and devices for preserving small numbers of sperm.It presents conventional freezing and vitrification techniques,evaluating their respective strengths and limitations in effectively preserving rare sperm,and compares the efficacy of using fresh versus cryopreserved testicular sperm.展开更多
Cryopreservation is a fundamental technology in biomedical research,regenerative medicine,and tissue engineering,enabling the long-term storage of cells,tissues,and organs.However,its effectiveness is limited by chall...Cryopreservation is a fundamental technology in biomedical research,regenerative medicine,and tissue engineering,enabling the long-term storage of cells,tissues,and organs.However,its effectiveness is limited by challenges such as intracellular ice formation,cryoprotectant toxicity,and reduced post-thaw viability.This review explores the crucial role of encapsulation in enhancing cryopreservation efficiency,with a focus on recent advances in materials science,bioengineering,and cryobiology.Emerging technologies,such as nanotechnology and stimuli-responsive polymers,are transforming encapsulation strategies.Innovations such as microfluidic systems offer precise control over cooling rates and cryoprotectant distribution,thereby mitigating conventional limitations.The review also addresses current obstacles related to scaling up encapsulation processes and ensuring the long-term biocompatibility and stability of preserved specimens.By synthesizing recent findings,this work provides a comprehensive resource for researchers and clinicians seeking to enhance biopreservation techniques and their applications in contemporary medicine and biotechnology.Finally,the review identifies critical knowledge gaps that must be addressed to improve the efficacy of cryopreservation strategies and advance their clinical translation.展开更多
Dear Editor,We are much obliged that Hadziselimovic1 has used our data2 to highlight the substantial proportion of boys with cryptorchidism where gonadotropin insufficiency is an important factor related to the pathog...Dear Editor,We are much obliged that Hadziselimovic1 has used our data2 to highlight the substantial proportion of boys with cryptorchidism where gonadotropin insufficiency is an important factor related to the pathogenesis.We have recently presented a study on a series of 453 consecutive boys with bilateral nonsyndromic cryptorchidism,in which we conducted hormonal evaluations and assessed germ cell numbers in testicular biopsies.3 In this series,45%of the boys were classified as having gonadotropin insufficiency.3 Identifying these patients at the time of surgery is important.A recent follow-up study of 208 boys with nonsyndromic bilateral cryptorchidism from our department showed that the boys with gonadotropin insufficiency had an impaired fertility potential after surgery compared to boys with an intact hypothalamus–pituitary–gonadal feedback mechanism.4 In a review from 2022,Hadziselimovic5 suggested that infertility in patients diagnosed with cryptorchid testes is a consequence of a hormonal deficiency rather than temperature-induced cellular damage.展开更多
Dear Editor,I would like to congratulate Mamsen et al.i on their extensive and scientifically valuable work.I analyzed their raw data presented in Table 1 of the original article from a different perspective and disco...Dear Editor,I would like to congratulate Mamsen et al.i on their extensive and scientifically valuable work.I analyzed their raw data presented in Table 1 of the original article from a different perspective and discovered an effect not mentioned in the article.My analysis showed that luteinizing hormone(LH)levels are significantly lower in patients at high infertility risk(HIR),whose testes lack A dark(Ad)spermatogonia and display an abnormal ratio of germ cells per crosssectional tubule(G/T).展开更多
Cryopreservation of living cells and tissues plays a vital role in biomedical research,clinical applications,biotechnology innovation,the development of new vaccines and drugs,and the conservation of endangered specie...Cryopreservation of living cells and tissues plays a vital role in biomedical research,clinical applications,biotechnology innovation,the development of new vaccines and drugs,and the conservation of endangered species.While significant technological breakthroughs have been achieved in cooling methods-particularly through vitrification for large tissue and organs-the lack of optimal rewarming technology remains a key obstacle to successful cryopreservation,especially for larger samples such as tissues and organs.The primary challenges during the warming process include non-uniformity heating and insufficient rewarming rates,which can lead to thermal stress-induced structural damage and lethal ice recrystallization,ultimately compromising the integrity and functionality of biological materials.In recent years,various advanced warming techniques have emerged,employing different energy conversion approaches to achieve volumetric heating while minimizing the risk of overheating.These techniques involve thermal,mechanical-thermal,and electromagnetic-thermal energy conversions.However,each method presents its own limitation.This review aims to summarize recent advancements in rewarming technologies for cryopreservation,with a focus on their mechanisms,applications,and the key challenges that must be addressed to enable broader adoption in medical and commercial contexts.展开更多
Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,D...Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,DNA fragmentation,and cytotoxicity associated with traditional cryoprotectants like dimethyl sulfoxide(DMSO).Recent breakthroughs have focused on improving post-thaw sperm viability with novel cryoprotectants and innovative freezing strategies.Prospective approaches include the use of amino acid-based cryoprotectants,deep eutectic solvents,and antioxidants that have been described to prevent oxidative damage and maintain DNA integrity.Vitrification,a high-speed freezing technique that prevents ice crystal formation,has demonstrated superior outcomes compared to conventional slow freezing.Moreover,the Direct Dropping Method,a cryoprotectant-free approach,has been introduced as a contamination-minimizing technique that preserves sperm functionality.Multiomics tools are also utilized to determine biomarkers for protocol optimization.Despite these advancements,cryoprotectant toxicity is a central challenge,emphasizing the necessity for safer agents.Future research must focus on long-term sperm functionality and individualized cryopreservation strategies to maximize reproductive outcomes.The current review highlights the challenges associated with sperm cryopreservation,explores innovative strategies and novel cryoprotectants,underscores the significance of maintaining DNA integrity,and proposes future research directions to improve fertility preservation outcomes.展开更多
Organoids are three-dimensional structures derived from stem cells that recapitulate the gene expression profiles and functional characteristics of their tissue of origin,rendering them invaluable tools for disease mo...Organoids are three-dimensional structures derived from stem cells that recapitulate the gene expression profiles and functional characteristics of their tissue of origin,rendering them invaluable tools for disease modeling,drug screening,and precision medicine.Despite their promise,the widespread application of organoids is limited by extended culture durations and technical complexity.Cryopreservation has emerged as a critical strategy to overcome challenges related to the long-term storage and application of organoids,offering a range of preservation approaches tailored to organoid development.Nevertheless,conventional cryopreservation techniques encounter significant limitations when applied to organoids.To address these issues,the development of naturally derived,low-toxicity Cryoprotectants(CPAs),along with the optimization of CPA loading methods and refinement of cooling and warming protocols,is essential to mitigate cryoinjury.Looking forward,the comprehensive enhancement of cryopreservation technologies may facilitate the transformation of organoids into“off-the-shelf”products,enabling scalable production,batch standardization,and centralized distribution.Such advancements will lay the foundation for the establishment of Next-Generation Living Biobanks(NGLB).展开更多
[Objective] The aim of this study was to establish the in vitro culture system of chicken fibroblasts.[Method] Tissue explant method and enzymatic digestion method were used to separate and culture chicken skin fibrob...[Objective] The aim of this study was to establish the in vitro culture system of chicken fibroblasts.[Method] Tissue explant method and enzymatic digestion method were used to separate and culture chicken skin fibroblasts respectively.The rate of cell growth,cryopreservation and recovery were compared.[Result] The primary chicken fibroblasts prepared by enzymatic digestion grew faster and converged together to form monolayer on 5 d post preparation;the passage cells prepared by these 2 methods grew at similar speed and formed monolayer within 2-3 d;homogeneous fibroblasts could be obtained by trypsin digestion and repeated attachment for 3-4 passages;there were 75%-80% of cells survived after cryopreservation and recovery;the growth curves of embryonic fibroblasts and skin fibroblasts were all normal and the two kind of cells still retained the normal number of chromosomes even at the twelfth passage.[Conclusion] The feeder layer cells needed for establishing ES cell lines could be obtained by culturing chicken fibroblasts through both tissue explant method and enzymatic digestion method.This study provided a basis for the successful establishment of ES cell lines.展开更多
Embryo cryopreservation（CP） has became a very important part of the clinical use of in vitro fertilization. Oocyte CP offers more advantages compared with embryo freezing with regard to less ethical, legal and moral...Embryo cryopreservation（CP） has became a very important part of the clinical use of in vitro fertilization. Oocyte CP offers more advantages compared with embryo freezing with regard to less ethical, legal and moral problems. However, the efficiency of this procedure is still low, which prevents its clinical application in wide range. The aim of our paper is to review the basic principles, technical and safety aspects and current status of oocyte cryopreservation in human assisted reproduction.展开更多
[Objective] This study aimed to investigate the effects of cryopreservation on the quality and ultrastructure of Tibetan Mastiff sperm. [Method] The effects of cryopreservation on the quality of Tibetan Mastiff sperm ...[Objective] This study aimed to investigate the effects of cryopreservation on the quality and ultrastructure of Tibetan Mastiff sperm. [Method] The effects of cryopreservation on the quality of Tibetan Mastiff sperm were evaluated via motility, membrane integrity rate and acrosome intact rate. On that basis, the effects of cryopreservation on ultrastructure of sperm were observed under SEM and TEM. [Result] In Experiment 1, EG gave the best results not only in post-thaw motility rate （36.3%）, but also in low membrane integrity rate （38.0%） and acrosome intact rate （42.0% ）, but there was no significant difference between EG group and Glycerol group （P0.05）. In Experiment 2, the 5 cm freezing height obtained the best freezing-thawing results, but there was no significant difference between 2 and 5 cm height （P 0.05）, besides in acrosome intact rate. In Experiment 3, SDS and Vc added separately or together into extenders could improve freezing-thawing results, but there was not obvious difference between SDS group and Vc group （P0.05）, besides the lower motility of Vc group （P0.05）. Addition of SDS and Vc obtained the best results in post-thaw motility rate （44.1%）, and also in membrane integrity rate （48.0%） and acrosome intact rate （48.2%）. The ultrastructure of frozen-thawed sperm was also evaluated under SEM and TEM, results showed that cryopreservation caused various degrees of damage to Tibetan Mastiff sperm, more serious damages were observed in the acrosome such as swelling, vesiculation and even disappearance. [Conclusion] This study confirms that EG, horizontal height of 0.25 ml straw above LN 2 surface and additives SDS and Vc together can improve freezing effect. However, cryopreservation has certain damage to ultrastructure of sperm.展开更多
Cryopreservation of few spermatozoa is still a major challenge for male fertility preservation. This study reports use a new micro-straw （LSL straw） for freezing few spermatozoa for intracytoplasmic sperm injection ...Cryopreservation of few spermatozoa is still a major challenge for male fertility preservation. This study reports use a new micro-straw （LSL straw） for freezing few spermatozoa for intracytoplasmic sperm injection （ICSI）. Semen samples from 22 fertile donors were collected, and each semen sample was diluted and mixed with cryoprotectant in a ratio of 1：1, and then frozen using three different straws such as LSL straw （50-100μl）, traditional 0.25 ml and 0.5 ml straws. For freezing, all straws were fumigated with liquid nitrogen, with temperature directly reducing to -130--140℃. Sperm concentration, progressive motility, morphology, acrosome integrity, and DNA fragmentation index were evaluated before and after freezing. After freezing-thawing, LSL straw group had significantly higher percentage of sperm motility than traditional 0.25 ml and 0.5 ml straw groups （38.5% vs 27.4% and 25.6%, P 〈 0.003）. Sperm motility and acrosomal integrity after freezing-thawing were significantly lower than that of before freezing. However, there was no significant difference in morphology, acrosome, and DNA integrity between the three types of straws （P 〉 0.05）. As LSL straws were thinner and hold very small volume, the freezing rate of LSL straw was obviously faster than 0.25 ml straw and 0.5 ml straws. In conclusion, LSL micro-straws may be useful to store few motile spermatozoa with good recovery of motility for patients undergoing ICSI treatment.展开更多
Aim:To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. Methods:Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. T...Aim:To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. Methods:Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. The spermatozoa were frozen in straws by liquid nitrogen vapor using egg-yolk-free Tes-Tris (mTTE) synthetic extender and glycerol as cryoprotectant.The effects of glycerol concentration (1%,3 %,5 %,10 % and 15 % [v/v]) and its equilibration time (10 min,30 min,60 min and 90 min) on post-thaw spermatozoa were examined by sperm motility and sperm head membrane integrity.Results:The post-thaw motility and head membrane integrity of spermatozoa were significantly higher (P<0.05) for 5 % glycerol (42.95±2.55 and 50.39±2.42,respectively) than those of the other groups (1%:19.19±3.22 and 24.84±3.64;3 %:34.23±3.43 and 41.37±3.42;10 %: 15.68±2.36 and 21.39±3.14;15 %:7.47±1.44 and 12.90±2.18).The parameters for 30 min equilibration (42.95±2.55 and 50.39±2.42) were better (P<0.05) than those of the other groups (10 min:31.33±3.06 and 38. 98±3.31;60 min:32.49±3.86 and 40.01±4.18;90 min:31.16±3.66 and 38.30±3.78).Five percent glycerol and 30 min equilibration yielded the highest post-thaw sperm motility and head membrane integrity.Conclusion: Cynomolgus monkey spermatozoa can be successfully cryopreserved in a chemically defined extender,which is related to the concentration and the equilibration time of glycerol.展开更多
Liver cell transplantation presents clinical benefit in patients with inborn errors of metabolism as an alternative,or at least as a bridge,to orthotopic liver transplantation.The success of such a therapeutic approac...Liver cell transplantation presents clinical benefit in patients with inborn errors of metabolism as an alternative,or at least as a bridge,to orthotopic liver transplantation.The success of such a therapeutic approach remains limited by the quality of the transplanted cells.Cryopreservation remains the best option for long-term storage of hepatocytes,providing a permanent and sufficient cell supply.However, isolated adult hepatocytes are poorly resistant to such a process,with a significant alteration both at the morphological and functional levels.Hence,the aim of the current review is to discuss the state of the art regarding widely-used hepatocyte cryopreservation protocols,as well as the assays performed to analyse the post-thawing cell quality both in vitro and in vivo. The majority of studies agree upon the poor quality and efficiency of cryopreserved/thawed hepatocytes as compared to freshly isolated hepatocytes.Intracellular ice formation or exposure to hyperosmotic solutionsremains the main phenomenon of cryopreservation process,and its effects on cell quality and cell death induction will be discussed.The increased knowledge and understanding of the cryopreservation process will lead to research strategies to improve the viability and the quality of the cell suspensions after thawing.Such strategies,such as vitrification,will be discussed with respect to their potential to significantly improve the quality of cell suspensions dedicated to liver cell-based therapies.展开更多
Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-...Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-1 for 3 weeks were encapsulated in calcium alginate beads. The beads were dehydrated in 0.4 molLl sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either -40℃ or -60℃ for 30 min, and stored in liquid nitrogen for 〉24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL^-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes survived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.展开更多
AIM To demonstrate the feasibility of cryopreservation of peripheral blood mononuclear cells(PBMCs) for prognostic circulating tumor cell(CTC) detection in gastroesophageal cancer.METHODS Using 7.5 m L blood samples c...AIM To demonstrate the feasibility of cryopreservation of peripheral blood mononuclear cells(PBMCs) for prognostic circulating tumor cell(CTC) detection in gastroesophageal cancer.METHODS Using 7.5 m L blood samples collected in EDTA tubes from patients with gastroesopheagal adenocarcinoma, CTCs were isolated by epithelial cell adhesion molecule based immunomagnetic capture using the Iso Flux platform. Paired specimens taken during the same blood draw(n = 15) were used to compare number of CTCs isolated from fresh and cryopreserved PBMCs. Blood samples were processed within 24 h to recover the PBMC fraction, with PBMCs used for fresh analysis immediately processed for CTC isolation. Cryopreservation of PBMCs lasted from 2 wk to 25.2 mo(median 14.6 mo). CTCs isolated from pre-treatment cryopreserved PBMCs(n = 43) were examined for associations with clinicopathological variables and survival outcomes.RESULTS While there was a significant trend to a decrease in CTC numbers associated with cryopreserved specimens(mean number of CTCs 34.4 vs 51.5, P = 0.04), this was predominately in samples with a total CTC count of > 50, with low CTC count samples less affected(P = 0.06). There was no significant association between the duration of cryopreservation and number of CTCs. In cryopreserved PBMCs from patient samples prior to treatment, a high CTC count(> 17) was associated with poorer overall survival(OS)(n = 43, HR = 4.4, 95%CI: 1.7-11.7, P = 0.0013). In multivariate analysis, after controlling for sex, age, stage, ECOG performance status, and primary tumor location, a high CTC count remained significantly associated with a poorer OS(HR = 3.7, 95%CI: 1.2-12.4, P = 0.03). CONCLUSION PBMC cryopreservation for delayed CTC isolation is a valid strategy to assist with sample collection, transporting and processing.展开更多
Low-density lipoprotein （LDL） extracted from hen egg yolk has recently been considered to be superior to whole egg yolk in sperm cryopreservation of various animal species. Meanwhile, there was a notion that high-de...Low-density lipoprotein （LDL） extracted from hen egg yolk has recently been considered to be superior to whole egg yolk in sperm cryopreservation of various animal species. Meanwhile, there was a notion that high-density lipoprotein （HDL） in egg yolk may have a negative effect on post-thaw survival. The role of LDL and HDL in sperm cryopreservation of rhesus monkeys has not been explored. The present study evaluates their effect in comparison with egg yolk with or without the addition of permeable cryoprotectant （glycerol） on sperm cryopreservation of rhesus macaques. In addition, various additives intended to change the lipid composition of LDL-sperm membrane complex have also been tested for their effectiveness in preserving post-thaw viability. Our findings indicated that LDL is the main component in egg yolk that is responsible for its protective role for sperm cryopreservation in rhesus monkeys. Regardless of the presence or absence of glycerol, the protective role of LDL is similar to that of egg yolk and we did not observe any superiority in post-thaw survival with LDL when compared to egg yolk. Modifying the lipid composition of LDL-sperm membrane complex with the addition of cholesterol, cholesterol loaded cyclodextrin and phosphatidylcholine also did not yield any improvements in pest-thaw survival; while addition of methyl-β-cyclodextrin reduced post-thaw motility. HDL plays a neutral role in sperm cryopreservation of rhesus monkeys. The present study suggests that egg yolk may still hold advantages when compared with LDL as effective components in extenders for sperm cryopreservation in rhesus monkeys.展开更多
In the 1960s,sperm cryopreservation was developed as a method to preserve fertility.Currently,techniques for the cryopreservation of human spermatozoa have been widely used in assisted reproduction.However,although sp...In the 1960s,sperm cryopreservation was developed as a method to preserve fertility.Currently,techniques for the cryopreservation of human spermatozoa have been widely used in assisted reproduction.However,although sperm cryobiology has made notable achievements,the optimal method for the recovery of viable spermatozoa after cryopreservation remains elusive.Postthawing sperm quality can be affected by cryoprotectants,ice formation,storage conditions,and osmotic stress during the freezing process.This review discusses recent advances in different cryopreservation techniques,cryoprotectants,and freezing and thawing methods during cryopreservation and new indications for the use of cryopreserved spermatozoa.展开更多
Cryodamages occur during sperm cryopreservation. Cryopreservation of fish sperm usually results in marked decrease in sperm quality, such as swelling or disruption of the plasma membrane, mi-tochondrial dysfunction, d...Cryodamages occur during sperm cryopreservation. Cryopreservation of fish sperm usually results in marked decrease in sperm quality, such as swelling or disruption of the plasma membrane, mi-tochondrial dysfunction, diminished sperm motility, impaired velocity, shorter motility period, denatura-tion, and release of some enzymes from spermatozoa. In this paper, damages in morphology, physiology, biochemistry and metabolism, and genetic integrity of fish semen after cryopreservation are discussed. New approaches in assessment of fish thawed sperm quality such as computer assisted sperm analysis, flow cytometic analysis combined with fluorescent probes and single cell gel electrophoresis are also briefly reviewed.展开更多
Cell cryopreservation has evolved as an important technology required for supporting various cell-based applications,such as stem cell therapy,tissue engineering,and assisted reproduction.Recent times have witnessed a...Cell cryopreservation has evolved as an important technology required for supporting various cell-based applications,such as stem cell therapy,tissue engineering,and assisted reproduction.Recent times have witnessed an increase in the clinical demand of these applications,requiring urgent improvements in cell cryopreservation.However,cryopreservation technology suff ers from the issues of low cryopreservation effi ciency and cryoprotectant(CPA)toxicity.Application of advanced biotechnology tools can signifi cantly improve post-thaw cell survival and reduce or even eliminate the use of organic solvent CPAs,thus promoting the development of cryopreservation.Herein,based on the diff erent cryopreservation mechanisms available,we provide an overview of the applications and achievements of various biotechnology tools used in cell cryopreservation,including trehalose delivery,hydrogel-based cell encapsulation technique,droplet-based cell printing,and nanowarming,and also discuss the associated challenges and perspectives for future development.展开更多
The changes in the cell ultrastructure of in vitro cultured shoot tips from dwarf genotype of kiwifruit （Actinidia chinensis Ganmi 5） during cryopreservation were investigated. Shoot tips were preserved in liquid ni...The changes in the cell ultrastructure of in vitro cultured shoot tips from dwarf genotype of kiwifruit （Actinidia chinensis Ganmi 5） during cryopreservation were investigated. Shoot tips were preserved in liquid nitrogen using vitrification, and the cell ultrastructure was examined using transmission electron microscopy （TEM）. The regular ultrastructure of the cell wall, cell membrane and nucleus of shoot tips could be damaged during the freezing and thawing associated with preservation using liquid nitrogen. The cell plasmolysis was increased and freezing tolerance was improved after precultufing and dehydrating in a preservation and vitrification solution （PVS2） （30% glycerol （Gly）＋ 15% ethylene glycol （EG）＋ 15% dimethylsulfoxide （DMSO） ＋ 0.4 mol L^-1 sucrose）. The structure of some cells with low degree of injury and reversible damage was similar to that of the control and they could undergo normal cell division and differentiation. Besides, they could recover automatically and regenerate after their reculture.展开更多
文摘Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia(OA)and nonobstructive azoospermia(NOA).For men with NOA,testicular sperm extraction(TESE)is the only method to obtain sperm for assisted reproductive technology(ART).Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts,cryopreservation of microdissection-TESE-obtained sperm is essential.Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts.After first delving into the physiological and molecular aspects of sperm cryopreservation,this review aims to examine the current methods and devices for preserving small numbers of sperm.It presents conventional freezing and vitrification techniques,evaluating their respective strengths and limitations in effectively preserving rare sperm,and compares the efficacy of using fresh versus cryopreserved testicular sperm.
基金supported by the National Natural Science Foundation of China(82172114)the"Challenge and Response"project for key and common technology research of Hefei(GJ2022SH08).
文摘Cryopreservation is a fundamental technology in biomedical research,regenerative medicine,and tissue engineering,enabling the long-term storage of cells,tissues,and organs.However,its effectiveness is limited by challenges such as intracellular ice formation,cryoprotectant toxicity,and reduced post-thaw viability.This review explores the crucial role of encapsulation in enhancing cryopreservation efficiency,with a focus on recent advances in materials science,bioengineering,and cryobiology.Emerging technologies,such as nanotechnology and stimuli-responsive polymers,are transforming encapsulation strategies.Innovations such as microfluidic systems offer precise control over cooling rates and cryoprotectant distribution,thereby mitigating conventional limitations.The review also addresses current obstacles related to scaling up encapsulation processes and ensuring the long-term biocompatibility and stability of preserved specimens.By synthesizing recent findings,this work provides a comprehensive resource for researchers and clinicians seeking to enhance biopreservation techniques and their applications in contemporary medicine and biotechnology.Finally,the review identifies critical knowledge gaps that must be addressed to improve the efficacy of cryopreservation strategies and advance their clinical translation.
文摘Dear Editor,We are much obliged that Hadziselimovic1 has used our data2 to highlight the substantial proportion of boys with cryptorchidism where gonadotropin insufficiency is an important factor related to the pathogenesis.We have recently presented a study on a series of 453 consecutive boys with bilateral nonsyndromic cryptorchidism,in which we conducted hormonal evaluations and assessed germ cell numbers in testicular biopsies.3 In this series,45%of the boys were classified as having gonadotropin insufficiency.3 Identifying these patients at the time of surgery is important.A recent follow-up study of 208 boys with nonsyndromic bilateral cryptorchidism from our department showed that the boys with gonadotropin insufficiency had an impaired fertility potential after surgery compared to boys with an intact hypothalamus–pituitary–gonadal feedback mechanism.4 In a review from 2022,Hadziselimovic5 suggested that infertility in patients diagnosed with cryptorchid testes is a consequence of a hormonal deficiency rather than temperature-induced cellular damage.
文摘Dear Editor,I would like to congratulate Mamsen et al.i on their extensive and scientifically valuable work.I analyzed their raw data presented in Table 1 of the original article from a different perspective and discovered an effect not mentioned in the article.My analysis showed that luteinizing hormone(LH)levels are significantly lower in patients at high infertility risk(HIR),whose testes lack A dark(Ad)spermatogonia and display an abnormal ratio of germ cells per crosssectional tubule(G/T).
基金supported by National Natural Science Foundation of China(Award Number:2346842).
文摘Cryopreservation of living cells and tissues plays a vital role in biomedical research,clinical applications,biotechnology innovation,the development of new vaccines and drugs,and the conservation of endangered species.While significant technological breakthroughs have been achieved in cooling methods-particularly through vitrification for large tissue and organs-the lack of optimal rewarming technology remains a key obstacle to successful cryopreservation,especially for larger samples such as tissues and organs.The primary challenges during the warming process include non-uniformity heating and insufficient rewarming rates,which can lead to thermal stress-induced structural damage and lethal ice recrystallization,ultimately compromising the integrity and functionality of biological materials.In recent years,various advanced warming techniques have emerged,employing different energy conversion approaches to achieve volumetric heating while minimizing the risk of overheating.These techniques involve thermal,mechanical-thermal,and electromagnetic-thermal energy conversions.However,each method presents its own limitation.This review aims to summarize recent advancements in rewarming technologies for cryopreservation,with a focus on their mechanisms,applications,and the key challenges that must be addressed to enable broader adoption in medical and commercial contexts.
文摘Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,DNA fragmentation,and cytotoxicity associated with traditional cryoprotectants like dimethyl sulfoxide(DMSO).Recent breakthroughs have focused on improving post-thaw sperm viability with novel cryoprotectants and innovative freezing strategies.Prospective approaches include the use of amino acid-based cryoprotectants,deep eutectic solvents,and antioxidants that have been described to prevent oxidative damage and maintain DNA integrity.Vitrification,a high-speed freezing technique that prevents ice crystal formation,has demonstrated superior outcomes compared to conventional slow freezing.Moreover,the Direct Dropping Method,a cryoprotectant-free approach,has been introduced as a contamination-minimizing technique that preserves sperm functionality.Multiomics tools are also utilized to determine biomarkers for protocol optimization.Despite these advancements,cryoprotectant toxicity is a central challenge,emphasizing the necessity for safer agents.Future research must focus on long-term sperm functionality and individualized cryopreservation strategies to maximize reproductive outcomes.The current review highlights the challenges associated with sperm cryopreservation,explores innovative strategies and novel cryoprotectants,underscores the significance of maintaining DNA integrity,and proposes future research directions to improve fertility preservation outcomes.
基金supported by the National Natural Science Foundation of China(52076140).
文摘Organoids are three-dimensional structures derived from stem cells that recapitulate the gene expression profiles and functional characteristics of their tissue of origin,rendering them invaluable tools for disease modeling,drug screening,and precision medicine.Despite their promise,the widespread application of organoids is limited by extended culture durations and technical complexity.Cryopreservation has emerged as a critical strategy to overcome challenges related to the long-term storage and application of organoids,offering a range of preservation approaches tailored to organoid development.Nevertheless,conventional cryopreservation techniques encounter significant limitations when applied to organoids.To address these issues,the development of naturally derived,low-toxicity Cryoprotectants(CPAs),along with the optimization of CPA loading methods and refinement of cooling and warming protocols,is essential to mitigate cryoinjury.Looking forward,the comprehensive enhancement of cryopreservation technologies may facilitate the transformation of organoids into“off-the-shelf”products,enabling scalable production,batch standardization,and centralized distribution.Such advancements will lay the foundation for the establishment of Next-Generation Living Biobanks(NGLB).
基金Supported by National Natural Science Foundation of China(30801353)Shandong Education Department Foundation Project(G08LG53)~~
文摘[Objective] The aim of this study was to establish the in vitro culture system of chicken fibroblasts.[Method] Tissue explant method and enzymatic digestion method were used to separate and culture chicken skin fibroblasts respectively.The rate of cell growth,cryopreservation and recovery were compared.[Result] The primary chicken fibroblasts prepared by enzymatic digestion grew faster and converged together to form monolayer on 5 d post preparation;the passage cells prepared by these 2 methods grew at similar speed and formed monolayer within 2-3 d;homogeneous fibroblasts could be obtained by trypsin digestion and repeated attachment for 3-4 passages;there were 75%-80% of cells survived after cryopreservation and recovery;the growth curves of embryonic fibroblasts and skin fibroblasts were all normal and the two kind of cells still retained the normal number of chromosomes even at the twelfth passage.[Conclusion] The feeder layer cells needed for establishing ES cell lines could be obtained by culturing chicken fibroblasts through both tissue explant method and enzymatic digestion method.This study provided a basis for the successful establishment of ES cell lines.
文摘Embryo cryopreservation（CP） has became a very important part of the clinical use of in vitro fertilization. Oocyte CP offers more advantages compared with embryo freezing with regard to less ethical, legal and moral problems. However, the efficiency of this procedure is still low, which prevents its clinical application in wide range. The aim of our paper is to review the basic principles, technical and safety aspects and current status of oocyte cryopreservation in human assisted reproduction.
基金Natural Science Foundation of Jiangsu Province (BK2008589)Qing Lan Project of Jiangsu ProvinceCooperation Project of Agricultural Production, Study and Research in Wuxi City~~
文摘[Objective] This study aimed to investigate the effects of cryopreservation on the quality and ultrastructure of Tibetan Mastiff sperm. [Method] The effects of cryopreservation on the quality of Tibetan Mastiff sperm were evaluated via motility, membrane integrity rate and acrosome intact rate. On that basis, the effects of cryopreservation on ultrastructure of sperm were observed under SEM and TEM. [Result] In Experiment 1, EG gave the best results not only in post-thaw motility rate （36.3%）, but also in low membrane integrity rate （38.0%） and acrosome intact rate （42.0% ）, but there was no significant difference between EG group and Glycerol group （P0.05）. In Experiment 2, the 5 cm freezing height obtained the best freezing-thawing results, but there was no significant difference between 2 and 5 cm height （P 0.05）, besides in acrosome intact rate. In Experiment 3, SDS and Vc added separately or together into extenders could improve freezing-thawing results, but there was not obvious difference between SDS group and Vc group （P0.05）, besides the lower motility of Vc group （P0.05）. Addition of SDS and Vc obtained the best results in post-thaw motility rate （44.1%）, and also in membrane integrity rate （48.0%） and acrosome intact rate （48.2%）. The ultrastructure of frozen-thawed sperm was also evaluated under SEM and TEM, results showed that cryopreservation caused various degrees of damage to Tibetan Mastiff sperm, more serious damages were observed in the acrosome such as swelling, vesiculation and even disappearance. [Conclusion] This study confirms that EG, horizontal height of 0.25 ml straw above LN 2 surface and additives SDS and Vc together can improve freezing effect. However, cryopreservation has certain damage to ultrastructure of sperm.
文摘Cryopreservation of few spermatozoa is still a major challenge for male fertility preservation. This study reports use a new micro-straw （LSL straw） for freezing few spermatozoa for intracytoplasmic sperm injection （ICSI）. Semen samples from 22 fertile donors were collected, and each semen sample was diluted and mixed with cryoprotectant in a ratio of 1：1, and then frozen using three different straws such as LSL straw （50-100μl）, traditional 0.25 ml and 0.5 ml straws. For freezing, all straws were fumigated with liquid nitrogen, with temperature directly reducing to -130--140℃. Sperm concentration, progressive motility, morphology, acrosome integrity, and DNA fragmentation index were evaluated before and after freezing. After freezing-thawing, LSL straw group had significantly higher percentage of sperm motility than traditional 0.25 ml and 0.5 ml straw groups （38.5% vs 27.4% and 25.6%, P 〈 0.003）. Sperm motility and acrosomal integrity after freezing-thawing were significantly lower than that of before freezing. However, there was no significant difference in morphology, acrosome, and DNA integrity between the three types of straws （P 〉 0.05）. As LSL straws were thinner and hold very small volume, the freezing rate of LSL straw was obviously faster than 0.25 ml straw and 0.5 ml straws. In conclusion, LSL micro-straws may be useful to store few motile spermatozoa with good recovery of motility for patients undergoing ICSI treatment.
文摘Aim:To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. Methods:Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. The spermatozoa were frozen in straws by liquid nitrogen vapor using egg-yolk-free Tes-Tris (mTTE) synthetic extender and glycerol as cryoprotectant.The effects of glycerol concentration (1%,3 %,5 %,10 % and 15 % [v/v]) and its equilibration time (10 min,30 min,60 min and 90 min) on post-thaw spermatozoa were examined by sperm motility and sperm head membrane integrity.Results:The post-thaw motility and head membrane integrity of spermatozoa were significantly higher (P<0.05) for 5 % glycerol (42.95±2.55 and 50.39±2.42,respectively) than those of the other groups (1%:19.19±3.22 and 24.84±3.64;3 %:34.23±3.43 and 41.37±3.42;10 %: 15.68±2.36 and 21.39±3.14;15 %:7.47±1.44 and 12.90±2.18).The parameters for 30 min equilibration (42.95±2.55 and 50.39±2.42) were better (P<0.05) than those of the other groups (10 min:31.33±3.06 and 38. 98±3.31;60 min:32.49±3.86 and 40.01±4.18;90 min:31.16±3.66 and 38.30±3.78).Five percent glycerol and 30 min equilibration yielded the highest post-thaw sperm motility and head membrane integrity.Conclusion: Cynomolgus monkey spermatozoa can be successfully cryopreserved in a chemically defined extender,which is related to the concentration and the equilibration time of glycerol.
基金Supported by The Belgian National Fund for Medical Research, the Région Wallonne-DGTRE(Grant WALEO/HEPATERA) and "La Fondation St Luc-ARC Thérapie Cellulaire"Stéphenne Xis recipient of a Grant-FNRS for cell cryopreservation
文摘Liver cell transplantation presents clinical benefit in patients with inborn errors of metabolism as an alternative,or at least as a bridge,to orthotopic liver transplantation.The success of such a therapeutic approach remains limited by the quality of the transplanted cells.Cryopreservation remains the best option for long-term storage of hepatocytes,providing a permanent and sufficient cell supply.However, isolated adult hepatocytes are poorly resistant to such a process,with a significant alteration both at the morphological and functional levels.Hence,the aim of the current review is to discuss the state of the art regarding widely-used hepatocyte cryopreservation protocols,as well as the assays performed to analyse the post-thawing cell quality both in vitro and in vivo. The majority of studies agree upon the poor quality and efficiency of cryopreserved/thawed hepatocytes as compared to freshly isolated hepatocytes.Intracellular ice formation or exposure to hyperosmotic solutionsremains the main phenomenon of cryopreservation process,and its effects on cell quality and cell death induction will be discussed.The increased knowledge and understanding of the cryopreservation process will lead to research strategies to improve the viability and the quality of the cell suspensions after thawing.Such strategies,such as vitrification,will be discussed with respect to their potential to significantly improve the quality of cell suspensions dedicated to liver cell-based therapies.
文摘Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-1 for 3 weeks were encapsulated in calcium alginate beads. The beads were dehydrated in 0.4 molLl sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either -40℃ or -60℃ for 30 min, and stored in liquid nitrogen for 〉24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL^-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes survived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.
文摘AIM To demonstrate the feasibility of cryopreservation of peripheral blood mononuclear cells(PBMCs) for prognostic circulating tumor cell(CTC) detection in gastroesophageal cancer.METHODS Using 7.5 m L blood samples collected in EDTA tubes from patients with gastroesopheagal adenocarcinoma, CTCs were isolated by epithelial cell adhesion molecule based immunomagnetic capture using the Iso Flux platform. Paired specimens taken during the same blood draw(n = 15) were used to compare number of CTCs isolated from fresh and cryopreserved PBMCs. Blood samples were processed within 24 h to recover the PBMC fraction, with PBMCs used for fresh analysis immediately processed for CTC isolation. Cryopreservation of PBMCs lasted from 2 wk to 25.2 mo(median 14.6 mo). CTCs isolated from pre-treatment cryopreserved PBMCs(n = 43) were examined for associations with clinicopathological variables and survival outcomes.RESULTS While there was a significant trend to a decrease in CTC numbers associated with cryopreserved specimens(mean number of CTCs 34.4 vs 51.5, P = 0.04), this was predominately in samples with a total CTC count of > 50, with low CTC count samples less affected(P = 0.06). There was no significant association between the duration of cryopreservation and number of CTCs. In cryopreserved PBMCs from patient samples prior to treatment, a high CTC count(> 17) was associated with poorer overall survival(OS)(n = 43, HR = 4.4, 95%CI: 1.7-11.7, P = 0.0013). In multivariate analysis, after controlling for sex, age, stage, ECOG performance status, and primary tumor location, a high CTC count remained significantly associated with a poorer OS(HR = 3.7, 95%CI: 1.2-12.4, P = 0.03). CONCLUSION PBMC cryopreservation for delayed CTC isolation is a valid strategy to assist with sample collection, transporting and processing.
基金This work was supported in part by funding from the National Natural Science Foundation of China （No. 30800845）, the Natural Science Fund for Distinguished Young Scholars of Zhejiang Province （No. R3100105）, and the NIH grants RR00169 and RR13439. We thank Dr. M. Anton for providing the detailed protocols of LDL and HDL extraction.
文摘Low-density lipoprotein （LDL） extracted from hen egg yolk has recently been considered to be superior to whole egg yolk in sperm cryopreservation of various animal species. Meanwhile, there was a notion that high-density lipoprotein （HDL） in egg yolk may have a negative effect on post-thaw survival. The role of LDL and HDL in sperm cryopreservation of rhesus monkeys has not been explored. The present study evaluates their effect in comparison with egg yolk with or without the addition of permeable cryoprotectant （glycerol） on sperm cryopreservation of rhesus macaques. In addition, various additives intended to change the lipid composition of LDL-sperm membrane complex have also been tested for their effectiveness in preserving post-thaw viability. Our findings indicated that LDL is the main component in egg yolk that is responsible for its protective role for sperm cryopreservation in rhesus monkeys. Regardless of the presence or absence of glycerol, the protective role of LDL is similar to that of egg yolk and we did not observe any superiority in post-thaw survival with LDL when compared to egg yolk. Modifying the lipid composition of LDL-sperm membrane complex with the addition of cholesterol, cholesterol loaded cyclodextrin and phosphatidylcholine also did not yield any improvements in pest-thaw survival; while addition of methyl-β-cyclodextrin reduced post-thaw motility. HDL plays a neutral role in sperm cryopreservation of rhesus monkeys. The present study suggests that egg yolk may still hold advantages when compared with LDL as effective components in extenders for sperm cryopreservation in rhesus monkeys.
基金supported by the National Natural Science Foundation of China(No.82001634)the China Postdoctoral Science Foundation(No.2019M661521).
文摘In the 1960s,sperm cryopreservation was developed as a method to preserve fertility.Currently,techniques for the cryopreservation of human spermatozoa have been widely used in assisted reproduction.However,although sperm cryobiology has made notable achievements,the optimal method for the recovery of viable spermatozoa after cryopreservation remains elusive.Postthawing sperm quality can be affected by cryoprotectants,ice formation,storage conditions,and osmotic stress during the freezing process.This review discusses recent advances in different cryopreservation techniques,cryoprotectants,and freezing and thawing methods during cryopreservation and new indications for the use of cryopreserved spermatozoa.
基金Funded by the National High Technology R&D Program of China (863 Program, Nos. 2001AA621100, 2003AA603510 and 2004AA603310).
文摘Cryodamages occur during sperm cryopreservation. Cryopreservation of fish sperm usually results in marked decrease in sperm quality, such as swelling or disruption of the plasma membrane, mi-tochondrial dysfunction, diminished sperm motility, impaired velocity, shorter motility period, denatura-tion, and release of some enzymes from spermatozoa. In this paper, damages in morphology, physiology, biochemistry and metabolism, and genetic integrity of fish semen after cryopreservation are discussed. New approaches in assessment of fish thawed sperm quality such as computer assisted sperm analysis, flow cytometic analysis combined with fluorescent probes and single cell gel electrophoresis are also briefly reviewed.
文摘Cell cryopreservation has evolved as an important technology required for supporting various cell-based applications,such as stem cell therapy,tissue engineering,and assisted reproduction.Recent times have witnessed an increase in the clinical demand of these applications,requiring urgent improvements in cell cryopreservation.However,cryopreservation technology suff ers from the issues of low cryopreservation effi ciency and cryoprotectant(CPA)toxicity.Application of advanced biotechnology tools can signifi cantly improve post-thaw cell survival and reduce or even eliminate the use of organic solvent CPAs,thus promoting the development of cryopreservation.Herein,based on the diff erent cryopreservation mechanisms available,we provide an overview of the applications and achievements of various biotechnology tools used in cell cryopreservation,including trehalose delivery,hydrogel-based cell encapsulation technique,droplet-based cell printing,and nanowarming,and also discuss the associated challenges and perspectives for future development.
文摘The changes in the cell ultrastructure of in vitro cultured shoot tips from dwarf genotype of kiwifruit （Actinidia chinensis Ganmi 5） during cryopreservation were investigated. Shoot tips were preserved in liquid nitrogen using vitrification, and the cell ultrastructure was examined using transmission electron microscopy （TEM）. The regular ultrastructure of the cell wall, cell membrane and nucleus of shoot tips could be damaged during the freezing and thawing associated with preservation using liquid nitrogen. The cell plasmolysis was increased and freezing tolerance was improved after precultufing and dehydrating in a preservation and vitrification solution （PVS2） （30% glycerol （Gly）＋ 15% ethylene glycol （EG）＋ 15% dimethylsulfoxide （DMSO） ＋ 0.4 mol L^-1 sucrose）. The structure of some cells with low degree of injury and reversible damage was similar to that of the control and they could undergo normal cell division and differentiation. Besides, they could recover automatically and regenerate after their reculture.
