Preliminary Results with an Apico-Aortic Valved Conduit (AAVC) Using Polyurethane and Aortic Allograft Valves

Stenosis of the left ventricular outflow tract is one of the most frequent congenital cardiac anomalies in dogs. The subvalvular stenosis is described as a ring of fibrous tissue located in the left ventricular outflow tract immediately below the aortic valve. The best method of surgical treatment in dogs seems to be relief of the aortic obstruction with a ventricular aortic prosthesis. A new trileaflet valve manufactured out of polyurethane has been developed. For the conduit a woven Dacron graft has been used. In 5 male dogs a valved conduit was implanted between the apex of the left ventricle and the aorta thoracica without using hypothermia and/or cardiopulmonary bypass. Four dogs survived the surgical procedure and showed no clinical symptoms postoperatively. Blood flow through the conduit was demonstrated postoperatively by angiocardiography for a maximum of 22 days, the longest surviving time being 8 weeks. Trials for the replacement of the artificial valve in the conduit by a canine aortic allograft valve are in progress. Studies were done with the cryopreservation of fresh aortic valves. Sterilization, cryoconservation, and storage methods for the allograft are described     

Predictors of sperm recovery after cryopreservation in testicular cancer

Our objective was to identify predictors of improved postthaw semen quality in men with testicular cancer banking sperm for fertility preservation. We reviewed 173 individual semen samples provided by 67 men with testicular germ cell tumor (TGCT) who cryopreserved sperm before gonadotoxic treatment between 1994 and 2010 at our tertiary university medical center. Our main outcomes measures were independent predictors for the greater postthaw total motile count (TMC) in men with TGCT. Men with NSGCT were more likely to be younger (P < 0.01) and had high cancer stage (II or III, P < 0.01) compared with men with seminoma. In our multiple regression model, NSGCT histology, use of density gradient purification, and fresh TMC > median fresh TMC each had increased odds of a postthaw TMC greater than median postthaw TMC. Interestingly, age, advanced cancer stage (II or III), rapid freezing protocol, and motility enhancer did not show increased odds of improved postthaw TMC in our models. In conclusion, men with TGCT or poor fresh TMC should consider preserving additional vials (at least 15 vials) before oncologic treatment. Density gradient purification should be routinely used to optimize postthaw TMC in men with TGCT. Larger, randomized studies evaluating cancer stage and various cryopreservation techniques are needed to assist in counseling men with TGCT regarding fertility preservation and optimizing cryosurvival.     

以细胞筛为载体的玻璃化冷冻和慢速程序化冷冻保存人卵巢组织的效果比较

目的比较以细胞筛为载体的玻璃化冷冻与慢速程序化冷冻用于人卵巢组织冷冻的效果。方法人卵巢组织取皮质切块后,随机分为3组:新鲜组织对照组(F组)、慢速程序化冷冻组(S组)及以细胞筛为载体玻璃化冷冻组(V组)。卵巢组织冷冻复苏后,固定切片后行苏木素-伊红染色,观察卵泡形态;使用TdT介导的dUTP缺口末端标记技术,观察卵泡凋亡情况;部分卵巢组织体外培养,隔日采集培养液后检测雌二醇(E2)浓度。比较三组卵泡正常形态率、卵泡凋亡率及E2浓度。结果与F组原始卵泡正常形态率(91.1%)相比,V组原始卵泡正常形态率(88.1%)无显著差异(P0.05),而S组原始卵泡正常形态率(79.6%)显著下降(P0.001);V组初级卵泡正常形态率(74.2%)与S组(73.6%)相似,但两组均低于F组(89.0%)(P0.05);凋亡检测中,3组凋亡率无显著差异(P0.05);体外培养2周,各组E2浓度持续上升,F组E2浓度显著高于S组、V组(P0.001),而S组与V组E2浓度无显著差异(P0.05)。结论以细胞筛为载体的玻璃化冷冻能较好地保存人卵巢组织,复苏后组织体外培养后,还可持续分泌E2。     

Methods of cryopreservation of testicular tissue with viable spermatogonia in pre-pubertal boys undergoing gonadotoxic cancer treatment

BACKGROUND: Banking of testicular tissue from pre-pubertal boys before gonadotoxic treatment is a crucial step in fertility preservation. We wanted to find optimal methods for cryopreservation of testicular tissue from pre-pubertal boys, modifying techniques developed for fetal and adult human testicular tissue cryopreservation. METHODS: Testicular tissue was collected from five pre-pubertal boys undergoing gonadotoxic treatment in a clinical programme. Two freezing protocols, originally developed for fetal and adult human testicular tissue, were applied for pre-pubertal testicular tissue cryopreservation. In both methods, 5% dimethyl sulphoxide (DMSO) was used as a cryoprotectant. The integrity of the tissue was investigated in non-frozen tissue cultured for 24 h and in cryopreserved-thawed tissue, using two different programmes. We also analysed frozen-thawed samples cultured for 24 h in comparison with untreated fresh fixed control tissue. Immunohistochemical analysis using anti-MAGE-A4, vimentin and CD34 monoclonal antibodies was performed in order to visualize and characterize the cryodamage of the different testicular cells and compartments. The structure of the tissue was evaluated using light microscopy. Qualitative control analysis was performed using transmission electron microscopy. RESULTS: No clear structural changes were observed in the fresh, fresh cultured and cryopreserved testicular tissue after using the protocol developed for adult testicular tissue. The programme earlier successfully used for human fetal testicular tissue cryopreservation caused more tissue damage. CONCLUSIONS: Pre-pubertal testicular tissue from boys facing gonadotoxic treatment survives cryopreservation, can be cryobanked and hopefully used for fertility preservation. Slow programmed freezing with DMSO as a cryoprotectant is efficient in maintaining the spermatogonia, Sertoli cells and stromal compartment during freezing, thawing and tissue culture.     

Spermatogonial survival after cryopreservation and short-term orthotopic immature human cryptorchid testicular tissue grafting to immunodeficient mice

BACKGROUND: Fertility preservation has become an urgent clinical requisite for prepubertal male cancer patients undergoing gonadotoxic treatment. As these patients do not yet produce spermatozoa for freezing, only immature tissue is available for storage. We studied the survival and proliferative activity of spermatogonia and Sertoli cells after cryopreservation of cryptorchid testicular tissue pieces followed by xenografting for 21 days. METHODS AND RESULTS: Single pieces of tissue from cryptorchid testes (2-9 mm(3)) of young boys (2-12 years) were cryopreserved, thawed and transplanted into the scrotum of mice. Quantitative morphometric and immunohistochemical techniques were used to evaluate the integrity of the tissue, as well as the survival and proliferative capacity of spermatogonia and Sertoli cells before and after freezing/thawing/grafting. Three weeks after grafting, cryopreserved tissue was removed and analysed. Most of the tubules (88.3%) were intact and there was no fibrosis or sclerosis, 14.5% of the initial spermatogonial population remained, as identified by the MAGE A4 antibody, and 32% of these cells showed proliferative activity evidenced by Ki67, compared to 17.8% before cryopreservation and grafting. The number of Sertoli cells was unchanged and 5.1% were Ki67-positive, compared to none at all before freezing and grafting. CONCLUSIONS: Through our orthotopic xenografting model, we have demonstrated the survival and proliferative activity of spermatogonia and Sertoli cells in cryopreserved immature human cryptorchid tissue. Testicular tissue banking may thus prove to be a promising technique for the preservation of fertility in prepubertal boys undergoing oncological treatments. As the stem cell niche is maintained, the cryopreserved tissue can potentially be used for future autotransplantation. In addition, whole tissue freezing does not exclude alternative clinical uses, including isolated cell transplantation after dissociation, selection and enrichment. However, as this work was done on cryptorchid tissue, studies on normal immature testicular tissue, involving longer grafting periods, are needed to demonstrate a differentiation capacity before clinical implementation. Ethical and safety issues should also be addressed.     

The Uruguayan semen donor population: A twenty-eight-year retrospective study

Several studies have reported a global decline in seminal quality over the years. The objective of this study was to describe the semen donor population of Uruguay through comparing data of successive samples banked by the same donors and the analysis of their semen and physical characteristics, ancestry origin and educational level. A total of 3,449 ejaculated samples collected from 71 donors, cryobanked between 1989 and March 2017 at Fertilab, were analysed. Results revealed a mean age of 23.90 ± 3.98 years, an average weight of 74.95 ± 1.09 kg and a mean height of 1.78 ± 0.06 m. The majority of the donors trace their origin to Europe (74.65%, 53/71) and 66.19% (47/71) have a level of education higher than secondary school. We observed longitudinal differences in two parameters, that is sperm concentration and semen volume. Sperm concentration declined, while semen volume increased significantly over the 28-year period. The results of the present study are in accordance with that of previous articles that also reported a decline in sperm concentration over time. However, no differences were observed in total sperm number per ejaculate due to the increase in semen volume values, thus reflecting no real changes in sperm production over time.     

High levels of oxidation–reduction potential in frozen-thawed human semen are significantly correlated with poor post-thaw sperm quality

This study examined the relationship between oxidation–reduction potential (ORP) in frozen-thawed semen and the post-thaw sperm parameters. Levels of ORP were measured in 25 samples from men presenting for routine infertility work-up and were expressed as millivolt (mV)/10⁶ sperm/ml. Frozen-thawed samples were examined for post-thaw total motility (TM%), progressive motility (PM%), total sperm count (TSC) and ORP. The cryo-survival rate (CSR) was calculated as post-thaw TM/pre-freeze TM × 100. Data are provided as median and interquartile range (25th and 75th percentiles). The post-thaw TM% (10.0% [4.00%, 15.1%]), PM% (5.88% [2.97%, 9.33%]) and TSC (12.5 [10.0, 17.5] × 10⁶ sperm) were significantly lower than the pre-freeze TM% (45.9% [32.9%, 59.1%], PM% (31.5% [24.4%, 40.0%] and TSC (120 [90, 250] ×10⁶ sperm) (p < .001). Post-thaw ORP (2.62 [2.52, 3.13] mV/10⁶ sperm/ml) was significantly higher than pre-freeze ORP (0.73 [0.54, 1.21] mV/10⁶ sperm/ml; p < .001). The CSR was 21.7% (11.3%, 31.9%). The post-thaw seminal ORP was negatively correlated with post-thaw TM% (r = −.5; p = .02), PM% (r = −.41; p = .03), TSC (r = −.60; p = .03) and CSR (r = −.52; p = .01). Increased levels of ORP are significantly correlated with poor post-thaw sperm quality and CSR.     

Impact of using a fast‐freezing technique and different thawing protocols on viability and fertility of frozen equine spermatozoa

The effects of freezing technique and thawing protocol on thawed semen viability and fertility were studied. Ejaculates from 5 stallions (n = 25) were frozen by conventional or a fast‐freezing technique. Frozen semen was thawed by two thawing protocols (37 °C 30 s^?1 or 75 °C 7 s^?1). Thawed semen was evaluated by progressive motility, vigour, morphology and plasma membrane integrity. Mares (n = 25) were inseminated with 300 (n = 11) or 150 (n = 14) million spermatozoa. A greater (P < 0.05) vigour and progressively motile spermatozoa were detected, respectively, at thawing and after 20 min post‐thawing in the fast‐freezing technique than in the conventional one. Plasma membrane integrity was also greater (P < 0.05) in semen frozen with the fast‐freezing technique. Semen viability was not affected by thawing protocol. Pregnancy rate using the fast‐freezing technique was 76% (19/25), and did not differ (P > 0.05) between insemination doses. We concluded that the 150 million progressively motile spermatozoa per dose using a deep‐horn insemination maximises the use of equine semen. The fast‐freezing technique, as compared to the conventional one, efficiently preserves the viability and fertilising capacity of spermatozoa, indicating a new method to improve the fertility of frozen equine semen.     

p53 and mitogen‐activated protein kinase pathway protein profiles in fresh and frozen spermatozoa

Sperm or testicular tissue cryopreservation is performed in cases of male infertility as a treatment for the preservation of fertility. When these sperm cells are used in assisted reproductive techniques, fertilisation rates, developmental and implantation potential of embryos decrease and the abortion rates increase. In the present work, differences of both phosphorylation and expression levels of p53 and Mitogen‐activated protein kinases (MAPK) proteins were analysed in 61 individual sperm samples before and after cryopreservation. We observed that p53 protein residue at Ser 15 was phosphorylated after cryopreservation. Because MAPK pathway activations may be involved in p53 phosphorylation, MAPK/ERK, Stress‐activated protein kinases (SAPK)/JNK and p38MAPK proteins were also investigated. Analysis showed that p38MAPK phosphorylations increased significantly. However, ERK and JNK expressions and phosphorylations decreased, although the differences were not statistically significant. According to our results, it may be suggested that cryopreservation process activates p53 via p38 MAPK pathway that subsequently causes apoptosis, which may be related to sperm parameters.     

组织工程学血管构建中脐带内皮细胞分离及冻存技术的初步研究

目的为制备组织工程学血管随时提供种子细胞,对人脐静脉内皮细胞分离、体外培养、传代及鉴定方法进行研究,并研究其冻存技术,探讨建立脐带血管内皮细胞库的可能性.方法新鲜脐带49务,脐静脉内灌注消化酶消化,获得内皮细胞,进行体外培养,相差显微镜下观察酶消化结果及所获内皮细胞贴壁生长规律;采用VⅢ因子免疫荧光染色,鉴定所获内皮细胞及其纯度;加入冻存液,置于液氮进行保存,复苏后,分别进行台酚蓝拒染试验及MTT还原试验,绘制细胞生长曲线.结果血管内灌注消化液法可获得取高纯度的内皮细胞,胰酶和胶原酶混合灌注法消化结果优于单纯胰酶及胰酶和EDTA组,各组消化时间均以10～15min为佳;混合酶消化组细胞获得率及贴壁结果均较其他二组为优.与未冻存细胞相比,复苏的细胞活力保持在95%以上.复苏后的内皮细胞的生长曲线与未冻存细胞的生长曲线无差异.结论脐静脉灌注酶消化法可获取足够数量及纯度的内皮细胞,混合酶消化法消化效果最佳,经体外培养扩增后,可提供足够数量及纯度的内皮细胞.冻存的内皮细胞复苏后仍保持较高的活力及体外增殖能力,能及时提供制备组织工程学血管的种子细胞来源.