Functional status of the Sertoli cell in azoospermic men.
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Humans↗
Biomedical subjects
Jan Tesarik
Publications and source records attributed to Jan Tesarik.
Microfilament disruption is required for enucleation and nuclear transfer in germinal vesicle but not metaphase II human oocytes.
OBJECTIVE: To evaluate the usefulness of microfilament disruption before enucleation and nuclear transfer in human oocytes at different stages of maturation. DESIGN: Prospective experimental study. SETTING: Private clinics. PATIENT(S): Infertile couples undergoing assisted reproduction attempts. INTERVENTION(S): Oocyte enucleation and nuclear transfer, activation of reconstructed oocytes. MAIN OUTCOME MEASURE(S): Oocyte survival, nuclear transfer efficacy, activation outcomes. RESULT(S): Survival rate and nuclear transfer efficacy of germinal vesicle oocytes exposed to the microfilament disrupting agent cytochalasin B before enucleation were 88% and 80%, respectively. These figures dropped, respectively, to 8% and 2% when cytochalasin treatment was omitted. By contrast, cytochalasin-treated and -untreated metaphase II oocytes showed similar survival rate (87% vs. 90%) and nuclear transfer efficacy (78% vs. 87%). This also applied to metaphase II oocytes matured in vitro from the germinal vesicle stage. Cytochalasin treatment did not affect activation rate of reconstructed oocytes, but it increased the occurrence of oocytes with multiple female pronuclei. CONCLUSION(S): Microfilament disruption before enucleation is required for germinal vesicle oocytes but not for metaphase II oocytes.
Actin Cytoskeleton↗
Blastomere cytoplasmic granularity is unrelated to developmental potential of day 3 human embryos.
PURPOSE: To examine whether the increase in cytoplasmic granularity observed in some human embryos on day 3 of development is of any predictive value as to embryo developmental potential. METHODS: Retrospective study comparing outcomes of treatment attempts in three groups of patients after day 3 embryo transfer. Attempts in which only embryos with clear cytoplasm were transferred form Group I, those in which only embryos with granulated cytoplasm were transferred constitute Group II, and Group III consists of cases with mixed transfer combining both types of embryos. Each group was further divided according to the female age. RESULTS: Clinical pregnancy rates in Groups I (314 attempts), II (173 attempts), and III (323 attempts) were 33.8, 36.4, and 31.3%, respectively. Implantations rates for Groups I-III were 17.0,17.3, and 14.8%, respectively. No significant differences between groups concerning these and other values, including the number of oocytes and of metaphase II oocytes recovered, fertilization and cleavage rates were found. The proportion of good-morphology embryos was also similar between the different groups (74.3, 72.7, and 70.2% respectively). The representation of women of advanced age (>36 years) was also similar in each group, and intergoup differences remained insignificant were only younger or only older women were taken into account. CONCLUSION(S): These data show that the appearance of cytoplasmic granulation in blastomeres of day 3 human embryos is of no prognostic value as to embryo quality and appears to be unrelated to the female age.
Adult↗
Associate editor's comment on 'Rescue ICSI of oocytes that failed to extrude the second polar body 6 h post-insemination in conventional IVF' by Chen and Kattera. Rescue ICSI revisited.
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Female↗
Pharmacological concentrations of follicle-stimulating hormone and testosterone improve the efficacy of in vitro germ cell differentiation in men with maturation arrest.
OBJECTIVE: To examine whether in vitro differentiation of germ cells from men with maturation arrest is improved by augmenting FSH and T concentrations above the values effective in samples from men with normal spermatogenesis. DESIGN: Prospective, controlled in vitro study. SETTING: Private assisted reproduction centers and a university department. PATIENT(S): Men with meiotic or postmeiotic maturation arrest. INTERVENTION(S): Testicular spermatid extraction, in vitro culture of testicular biopsy samples, intraoocyte injection of elongated spermatids, embryo culture and transfer. MAIN OUTCOME MEASURE(S): Progression of in vitro germ cell differentiation, fertilization, and pregnancy outcomes with in vitro cultured germ cells. RESULT(S): In some cases of meiotic and postmeiotic maturation arrest, more advanced germ cell stages were achieved by in vitro culture in the presence of 500 IU/L FSH as compared with 50 IU/L FSH. The beneficial effect of 500 IU/L FSH was further potentiated by a simultaneous increase of T concentration from 1 to 10 microM. Fertilizations with germ cells recovered after incubation with these pharmacological hormone concentrations gave rise to viable embryos and the births of five healthy babies. CONCLUSION(S): Pharmacological concentrations of FSH and T are beneficial for in vitro maturation of germ cells from some men with in vivo maturation arrest.
Biopsy↗
Laser-assisted removal of necrotic blastomeres from cryopreserved embryos that were partially damaged.
OBJECTIVE: To examine whether the developmental potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres before embryo transfer. DESIGN: Prospective pilot study and observational clinical series. SETTING: Private hospital. PATIENT(S): Two hundred thirty-five infertile couples undergoing frozen embryo transfer. INTERVENTION(S): Removal of necrotic blastomeres from frozen-thawed human embryos. MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): Removal of necrotic blastomeres from partially damaged frozen-thawed embryos before transfer increased rates of pregnancy (45.7% vs. 17.1%), ongoing pregnancy (40.0% vs. 11.4%) and ongoing implantation (16.2% vs. 4.3%) compared with the control group, in which necrotic blastomeres were not removed. A similarly high implantation rate (16.7%) was seen a subsequent clinical series in which necrotic blastomeres were removed from all partially damaged embryos. CONCLUSION(S): The viability of partially damaged frozen-thawed embryos can be improved by removal of necrotic blastomeres before embryo transfer.
Adult↗
Use of a modified intracytoplasmic sperm injection technique to overcome sperm-borne and oocyte-borne oocyte activation failures.
OBJECTIVE: To examine whether sperm-borne and oocyte-borne oocyte activation failures can be overcome by mechanical means that entail modifying the ICSI technique. DESIGN: Case report series. SETTING: Private clinics. PATIENT(S): Six infertile couples undergoing ICSI. INTERVENTION(S): Standard ICSI and modified ICSI based on mechanical manipulation that facilitated entry of calcium into the oocyte. MAIN OUTCOME MEASURE(S): Fertilization rate and pregnancy outcome. RESULT(S): In three cases of sperm-borne and three cases of oocyte-borne oocyte activation deficiencies, the modified ICSI technique enabled normal fertilization and development of embryos with good morphology. In terms of fertilization, the efficacy of modified ICSI was similar to use of a calcium ionophore, without producing extensive embryo fragmentation during postfertilization development. Term pregnancies resulting in the birth of normal children were achieved with the modified ICSI technique in five cases. CONCLUSION(S): Sperm-borne and oocyte-borne oocyte activation failures can be overcome by modifying the ICSI technique. The modification obviates the need to use insufficiently tested and potentially harmful drugs.
Adult↗
Paternal effects acting during the first cell cycle of human preimplantation development after ICSI.
BACKGROUND: The ability of human embryos to undergo normal development has been shown previously to be subject to strong paternal (sperm-derived) effects. This study was undertaken to determine whether paternal influences on human embryo quality are detectable as early as the first cell cycle after fertilization. METHODS: The quality of zygotes and cleaving embryos resulting from sibling donor oocytes fertilized by sperm from different patients were compared in a donor oocyte-sharing programme. RESULTS: Fertilizations with sperm from certain individuals repeatedly resulted in the formation of high proportions of zygotes with abnormal pronuclear morphology that subsequently tended to cleave slowly and to show extensive fragmentation and blastomere irregularities. This phenomenon was observed with oocytes from two different donors for each of these individuals and contrasted with normal developmental performance of embryos resulting from sibling oocytes fertilized by sperm from other men with similar basic sperm characteristics. Fertilization rates were not related to these differences. CONCLUSIONS: These data point to a very early onset of paternal effects that condition human embryo development. These effects may be both of genetic (related to the minor gene activity of the male pronucleus) or epigenetic (related to the sperm-derived oocyte-activating factor or sperm centrosome) origin.
Adult↗
Calcium signalling in human oocytes and embryos: two-store model revival.
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Calcium Channels↗
Effects of exogenous LH administration during ovarian stimulation of pituitary down-regulated young oocyte donors on oocyte yield and developmental competence.
BACKGROUND: The role of exogenous LH supplementation in ovarian stimulation is a matter of debate. Here we evaluate the impact of exogenous LH on oocyte yield and developmental competence in an oocyte donation programme. METHODS: Oocyte donors were randomized (computer-generated randomization list) to groups stimulated with FSH alone or with a combination of FSH and LH after pituitary down-regulation with a GnRH agonist administered in the mid-luteal phase. RESULTS: In donors with deep suppression of pituitary LH (<1 IU/l) before the beginning of ovarian stimulation, the inclusion of exogenous LH resulted in an increase in the number of mature oocytes and good-quality zygotes and embryos as well as higher implantation rates when compared with stimulation with FSH alone. In contrast, the inclusion of exogenous LH in the stimulation of donors with pre-stimulation serum LH of >or=1 IU/l impaired embryo morphology and lowered the implantation rate, although it increased the number of metaphase II oocytes. CONCLUSIONS: The inclusion of exogenous LH to the ovarian stimulation protocol can have beneficial or detrimental effects on oocyte yield and quality, depending on the level of endogenous LH. These data support the concept of a 'window' for LH requirement in ovarian stimulation.
Adult↗
Relationship between time period after vasectomy and the reproductive capacity of sperm obtained by epididymal aspiration.
BACKGROUND: It is not well defined whether the elapsed time after vasectomy has any influence on the outcome of IVF-ICSI using epididymal sperm. We analysed retrospectively the results of 151 ICSI cycles in which sperm of vasectomized men were used at different time periods after vasectomy. METHODS: Oocytes were obtained after a desensitizing ovarian stimulation protocol using GnRH agonist in association with recombinant FSH and HCG. Sperm were retrieved by percutaneous epididymal sperm aspiration. The cycles were split into three groups: < or =10 years after vasectomy (group 1, n = 47), 11-19 years after vasectomy (group 2, n = 79), and > or =20 years after vasectomy (group 3, n = 25). RESULTS: As might be expected, the mean age of men differed in the three groups (group 3 > group 2 > group 1), and the mean age of the women was also significantly higher in group 3 than in groups 1 and 2, although no differences were described between groups 2 and 3. All other laboratory and clinical parameters were similar in the three groups. Ongoing pregnancy and implantation rates (34, 25, 8% and 22, 15, 6% respectively) decreased significantly from group 1 to group 3. CONCLUSION: Pregnancy and implantation rates after ICSI with sperm from vasectomized men are negatively correlated with the time interval from vasectomy, which cannot be explained purely by male or female ageing.
Adult↗
Follicular fluid markers of oocyte developmental potential.
BACKGROUND: Concentrations of certain substances in follicular fluid (FF) are related to fertilization outcome and early post-fertilization development. The study aim was to identify FF markers with which to predict embryo implantation potential. METHODS: Concentrations of selected hormones, cytokines and growth factors in individual FF samples obtained during assisted reproduction treatment were related with treatment outcomes. RESULTS: Mean concentrations of LH, growth hormone (GH), prolactin (PRL), 17beta-estradiol (E2) and insulin-like growth factor (IGF)-I were higher, and that of interleukin-1 (IL-1) was lower, in treatment attempts leading to a clinical pregnancy as compared with those in which no pregnancy was established. Concentrations of FSH, progesterone, tumour necrosis factor-alpha and IGF-II were similar in successful and unsuccessful attempts. In successful attempts, LH and GH levels were higher in those follicles from which oocytes giving rise to transferred embryos (i.e. embryos with best morphology and fastest cleavage rate) originated, as compared with other follicles from which a mature oocyte was recovered but was cryopreserved for later use. CONCLUSIONS: FF levels of LH, GH, PRL, E2, IGF-I and IL-1 may serve to analyse cases of repeated assisted reproduction failures and to assess effects of modifications of the ovarian stimulation protocol.
Adult↗
Caspase activity in preimplantation human embryos is not associated with apoptosis.
BACKGROUND: Previous studies on mammalian preimplantation embryos have suggested an association between caspase activation, blastomere fragmentation and apoptosis. However, some reports on human embryos questioned the causal relationship between blastomere fragmentation and apoptosis, and information about the presence and activity of caspases in human embryos is lacking. METHODS: A fluorochrome-labelled universal caspase inhibitor was used to visualize active caspases in blastomeres and fragments of preimplantation human embryos. RESULTS: Caspase activity was detected only after fertilization, and was rare in blastomeres but frequent in fragments. The incidence of caspase activity in blastomeres and fragments was stable between the 2-cell and 12-cell stages. Caspase-positive blastomeres were only seen in poor-morphology embryos. The percentage of caspase-positive fragments was increased in embryos with multinucleated blastomeres but was unrelated to embryo morphology. Moreover, caspase-positive fragments detached from healthy blastomeres that were isolated by embryo biopsy and subsequently underwent mitotic division in culture. CONCLUSIONS: These data suggest that caspases in preimplantation human embryos are involved in developmental processes unrelated to cell death.
Apoptosis↗
In-vitro effects of FSH and testosterone withdrawal on caspase activation and DNA fragmentation in different cell types of human seminiferous epithelium.
BACKGROUND: Caspases are downstream elements of apoptosis-mediating pathways initiated by the Fas ligand/Fas receptor system which is supposed to play a central role in the regulation of apoptosis in the human seminiferous epithelium. However, caspase activity in different cell types of this epithelium has never been addressed. METHODS AND RESULTS: We evaluated caspase activity and DNA integrity in Sertoli and germ cells within in-vitro cultured segments of human seminiferous tubules after induction of apoptosis by FSH or testosterone withdrawal. FSH withdrawal increased the incidence of DNA fragmentation in meiotic (primary spermatocytes) and post-meiotic (spermatids) germ cells without producing any detectable effect on caspase activity in these cells and without affecting DNA integrity or caspase activity in Sertoli cells. Testosterone withdrawal stimulated caspase activity and produced DNA fragmentation in Sertoli cells, but showed only a weak effect on DNA fragmentation in germ cells and did not alter germ cell caspase activity. CONCLUSIONS: These findings confirm the central role of caspases in apoptosis of Sertoli cells. However, they also suggest that acute apoptosis of germ cells in the adult human testis occurs in a caspase-independent way and is controlled by Sertoli cells via an as yet undetermined mechanism.
Apoptosis↗
Day 3 embryo transfer with combined evaluation at the pronuclear and cleavage stages compares favourably with day 5 blastocyst transfer.
BACKGROUND: The respective advantages of day 3 and day 5 embryo transfer are a matter of debate. Previous comparisons did not include pronuclear stage zygote scoring and cumulative success rates (fresh and cryopreserved embryos). METHODS: Patients were randomized prospectively for day 3 or day 5 embryo transfer. Day 3 embryos were selected for transfer and cryopreservation by using combined evaluation at the pronuclear and cleavage stages. RESULTS: There was no difference between day 3 and day 5 fresh embryo transfers as to the rates of pregnancy (58 versus 62%), clinical pregnancy (56 versus 58%), delivery (50 versus 48%), implantation (35 versus 38%) and birth (33 versus 36%) rates. The corresponding values for cryopreserved embryo transfers were also similar. However, day 3 embryo transfer compared favourably with day 5 transfer when the pregnancy (90 versus 66%), clinical pregnancy (85 versus 62%) and delivery (77 versus 52%) rates were calculated per oocyte recovery attempt. CONCLUSIONS: With a selected population of good prognosis patients and our embryo selection criteria, the implantation potential of day 3 and day 5 embryos is equal. Per oocyte recovery attempt, day 3 transfer is more clinically efficient than day 5 transfer, but at least one transfer of cryopreserved embryos is necessary to manifest this superiority.
Adult↗
Definitions of human fertilization and preimplantation growth revisited.
Assisted reproductive techniques and the science of embryology have advanced rapidly over the last decades. The fact that social and moral objectives vary from country to country has resulted in differences not only in legislation, but also in the definition of embryological terms. Among the latest additions to the field has been nuclear transfer technology, which has led to concerns about the possibilities of human cloning. These facts call for a review of gametogenesis and early embryogenesis. The aim of the present paper is to initiate a discussion on terminology with a view to reaching a consensus. As a starting point definitions are proposed for the most important terms.
Journal Article↗
Using the male gamete for assisted reproduction: past, present, and future.
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Animals↗
Luteinizing hormone affects uterine receptivity independently of ovarian function.
Previous studies have suggested that LH, in addition to its well-known effects on the ovary, may exert direct effects on the uterus. This study evaluated the effects of mid-cycle administration of human chorionic gonadotrophin (HCG), which signals through the LH receptor, on endometrial thickness and uterine receptivity in two groups of women lacking ovarian activity and receiving embryos from an oocyte donation programme. Patients in one group still had ovulatory cycles, but their ovarian function was suppressed by pituitary down-regulation with a gonadotrophin-releasing hormone (GnRH) agonist in the embryo transfer cycle, resulting in low endogenous LH concentrations. Patients in the other group were menopausal women whose pituitary function was not down-regulated in the embryo transfer cycle and whose endogenous LH concentrations were thus high. Patients in each of the two groups were randomized into two subgroups. Patients in one subgroup were given 5000 IU of HCG 2 days before oocyte recovery in the corresponding donor. Patients in the other subgroup received placebo at the same time. Oocytes from each donor were randomly distributed between one patient from the HCG subgroup and one patient from the placebo subgroup in each patient group. Endometrial growth and secretory transformation were stimulated by sequential treatment with oestradiol valerate and progesterone. In women with low endogenous LH receiving placebo, endometrial thickness stopped increasing at the beginning of secretory transformation. Mid-cycle HCG administration resulted in a continuous increase in endometrial thickness through this period, improved the implantation rate after embryo transfer in these women (30.6 versus 20.7%) and augmented the number of multiple pregnancies. No similar stagnation of endometrial thickness and no effects of mid-cycle HCG administration on endometrial thickness, the implantation rate and the number of multiple pregnancies were found in women with high endogenous LH. It is concluded that endometrial maturation is disturbed in women with low endogenous LH but can be rescued by mid-cycle stimulation of LH receptor with exogenous HCG in the absence of ovarian activity.
Adult↗