Nuclear envelope remodelling during human spermiogenesis involves somatic B-type lamins and a spermatid-specific B3 lamin isoform

The nuclear lamina (NL) is a filamentous protein meshwork, composed essentially of lamins, situated between the inner nuclear membrane and the chromatin. There is mounting evidence that the NL plays a role in spermatid differentiation during spermiogenesis. The mouse spermatid NL is composed of the ubiquitous lamin B1 and the spermatid-specific lamin B3, an N-terminally truncated isoform of lamin B2. However, nothing is known about the NL in human spermatids. We therefore investigated the expression pattern and localization of A-type lamins (A, C and C2) and B-type lamins (B1, B2 and B3) during human spermiogenesis. Here, we show that a lamin B3 transcript is present in human spermatids and that B-type lamins are the only lamins detectable in human spermatids. We determine that, as shown for their mouse counterparts, human lamin B3, but not lamin B2, induces strong nuclear deformation, when ectopically expressed in HeLa cells. Co-immunofluorescence revealed that, in human spermatids, B-type lamins are present at the nuclear periphery, except in the region covered by the acrosome, and that as the spermatid matures the B-type lamins recede towards the posterior pole. Only lamin B1 remains detectable on 33-47% of ejaculated spermatozoa. On spermatozoa selected for normal head density, however, this fell to <6%, suggesting that loss of the NL signal may be linked to complete sperm nucleus compaction. The similarities revealed between lamin expression during human and rodent spermiogenesis, strengthen evidence that the NL and lamin B3 have conserved functions during the intense remodelling of the mammalian spermatid nucleus.

Prognosis factors of pregnancy after intrauterine insemination with the husband's sperm: conclusions of an analysis of 2,019 cycles

OBJECTIVE

To identify the prognostic factors for pregnancy after intrauterine insemination with the husband's sperm (IUI-H).

DESIGN

Retrospective study.

SETTING

A single university medical center.

PATIENT(S)

851 couples, for 2,019 IUI-H cycles.

INTERVENTION(S)

After controlled ovarian stimulation, IUI-H performed 36 hours after ovulation triggering or 24 hours after a spontaneous luteinizing hormone (LH) surge.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate per cycle (PR) and delivery rate per cycle (DR).

RESULT(S)

The overall PR was 14.8% and DR 10.8%. Higher PR and DR were observed for patients presenting with ovulation disorders (particularly polycystic ovary syndrome) or with male infertility. Secondary infertility in the woman appeared to be a positive prognostic factor as did a basal follicle-stimulating hormone (FSH) level ≤ 7 IU/L and ovulation triggering over spontaneous LH rise. The other parameters influencing the results were the women's age, the number of mature follicles obtained (≥ 2), the endometrial thickness (10-11 mm), and the number of progressive motile spermatozoa inseminated (>1 million).

CONCLUSION(S)

In women aged ≤ 38 years, IUI-H should be considered as an option, particularly in cases of female infertility from ovulation disorders, in cases of a normal ovarian reserve, in cases of secondary infertility, or when ≥ 1 million progressive sperm are inseminated. Bifollicular stimulation is required. In other cases, in vitro fertilization should be discussed as the first-line treatment.

Should sperm be cryopreserved after spinal cord injury?

In spinal cord injured (SCI) patients, three main factors may cause infertility: erectile dysfunction, ejaculatory dysfunction and impaired semen quality. This letter aims to discuss how we can manage SCI patients’ fertility in accordance with patient-centred care. For such SCI patients aged 20 to 40, having children represents hope for the future. Furthermore, it is a way to rebuild a life after the spinal injury and must be seen as an important part of the rehabilitation program. We suggest that sperm cryopreservation may contribute to patient-centred care management of SCI patients’ fertility, although there is no scientific evidence that cryopreservation will improve fertility outcome after SCI. Indeed, sperm cryopreservation is an affordable and simple technique in specialised centres with trained staff. Here, a protocol to manage SCI patients’ fertility is discussed: we propose PVS for sperm banking to all SCI patients after the phase of spinal shock during the rehabilitation program. If live sperm are retrieved, they are frozen and stored; however, if no live sperm are retrieved, electroejaculation and/or surgical sperm extraction are proposed only for patients who desire biological fatherhood. Prospective studies on the evolution of semen parameters, ejaculatory dysfunction, post-infectious obstructions and spermatogenesis impairment in chronic SCI patients are urgently needed to provide robust data for the evidence-based management of SCI patients’ fertility. Even if use rates are expected to be low, sperm banking may be a simple and affordable preventative measure for selected male SCI patients.

Sperm cryopreservation before cancer treatment: a 15-year monocentric experience

Sperm banking is an important procedure to preserve fertility before cancer therapy. The aim of this study was to comprehensively analyse cryopreservation activity retrospectively for 1080 patients referred to the sperm bank for sperm cryopreservation before cancer treatment. This study included 1007 patients diagnosed with testicular cancer (TC) (41.7%), lymphoma (26%), other haematological cancers (9.4%) or other types of cancer (22.8%); of these, 29 patients did not produce any semen sample and cryopreservation was impossible for 67 patients. Semen characteristics before treatment were within normal ranges, except moderate asthenospermia. Sperm concentration was significantly lower in TC than in non-TC. Straws from 57 patients (6.3%) were used in assisted reproductive technologies, which led to a 46.8% cumulative birth rate. Straws were destroyed for 170 patients (18.7%) and 140 patients performed semen analyses after cancer therapy. After an average delay of 22.5 months after the end of therapy, 43 patients (30.7%) exhibited azoospermia. This study of a large population of cancer patients revealed a high level of successful sperm storage. Utilization of cryopreserved spermatozoa led to good chances of fatherhood. Nevertheless, sperm banks should be aware of the low rates of straw use and straw destruction by cancer patients.

Tobacco consumption and benzo(a)pyrene-diol-epoxide-DNA adducts in spermatozoa: in smokers, swim-up procedure selects spermatozoa with decreased DNA damage

OBJECTIVE

To analyze the distribution of benzo(a)pyrene-diol-epoxide (BPDE)-DNA adducts in spermatozoa selected and nonselected by a swim-up procedure with relation to smoking habits.

DESIGN

Comparative study.

SETTING

Public university and public university hospital.

PATIENT(S)

Seventy-nine men (37 smokers and 42 nonsmokers) who visited an infertility clinic for diagnostic.

INTERVENTION(S)

Tobacco and environmental exposure assessment, semen sample analysis, swim-up procedure, BPDE-DNA adduct immunolabeling.

MAIN OUTCOME MEASURE(S)

BPDE-DNA adduct quantification in selected (SEL-SPZ) and nonselected (NONSEL-SPZ) spermatozoa. Data were normalized by using a normalized fluorescence value (NFV).

RESULT(S)

The mean NFV (±SD) in SEL-SPZ was significantly higher in smokers than in nonsmokers (18.9±11.5 vs. 10.5±10.4, respectively). Within smokers, a paired analysis (SEL-SPZ and NONSEL-SPZ) showed that NFV was significantly lower in SEL-SPZ than in NONSEL-SPZ (20.0±11.3 vs. 31.5±16.0, respectively). Conversely, within nonsmokers, the mean NFV was higher in SEL-SPZ than in NONSEL-SPZ (10.3±10.6 vs 4.3±7.1, respectively).

CONCLUSION(S)

Tobacco consumption is associated with BPDE-DNA adducts in spermatozoa. In smokers, semen processing by swim-up recovers potentially fertilizing spermatozoa that show a significantly lower amount of BPDE-DNA adducts compared with NONSEL-SPZ. Further study is needed to improve the spermatozoa selection in smoking patients requiring assisted reproductive technologies.

Meiotic arrest at the midpachytene stage in a patient with complete azoospermia factor b deletion of the Y chromosome

OBJECTIVE

To study the meiosis of a patient with complete azoospermia factor (AZF)b deletion of the Y chromosome.

DESIGN

Case report.

SETTING

La Conception University Hospital, Marseille, France.

PATIENT(S)

One azoospermic patient.

INTERVENTION(S)

Yq deletion testing, testicular sperm extraction, and meiotic study with immunocytochemistry.

MAIN OUTCOME MEASURE(S)

Abnormal synapsis rates in spermatocytes.

RESULT(S)

We found that most spermatocytes were at an early stage of meiosis. Half of the meiotic germ cells analyzed showed asynapsis, which was mostly extended or total. Discontinuity in the synaptonemal complex was seen in one third of the meiotic cells analyzed. An unusually small number of normal pachytene nuclei were found, all at early pachytene substages.

CONCLUSION(S)

This is the first demonstration that the synaptic process is impaired in a man with complete deletion of the AZFb interval. Our findings provide evidence that the pachytene checkpoint is situated at the midpachytene substage in humans.

Meiotic anomalies in infertile men with severe spermatogenic defects

BACKGROUND

This study was aimed at evaluating the rate of pairing failure in pachytene spermatocytes of patients presenting either an obstructive (O) or a non-obstructive (NO) infertility.

METHODS

Forty-one patients and 13 controls underwent testicular biopsy. Among the patients, 19 had an O infertility and 22 a NO infertility. Preparations of all patients and controls were Giemsa-stained, and synaptonemal complexes from nine of these patients and one control were immunostained.

RESULTS

In all, 2931 pachytene nuclei were analysed. The mean rate of asynapsed nuclei from the NO group (25.4%) was significantly higher than that of the O group (9.8%). There was no significant difference between the O group and the controls (10.6%). Immunocytochemistry showed that the number of pachytene nuclei decreased from the early to late pachytene sub-stage in all patients. Two NO patients, one azoospermic and one oligozoospermic, had a high percentage of asynapsed nuclei (86 and 91.8% respectively); one of these patients also presented a precocious localized separation of sister chromatids.

CONCLUSION

high levels of extended asynapsis could arise from a primary meiotic defect which may be responsible for 9% of the NO male infertilities at our centre. The prevalence of early pachytene substages suggests that the pachytene checkpoint is localized at the mid-pachytene stage in humans.

A truncated HCV core protein elicits a potent immune response with a strong participation of cellular immunity components in mice

The immunogenicity of a truncated HCV core protein (Co.120) was studied in BALB/c and C57BL/6 mice, given three intramuscular injections of antigen, adjuvanted with either aluminum hydroxide or Freund's adjuvant. A rapid antibody response was noted after the first dose, with both strains of mice eventually exhibiting comparable levels of anti-core IgG (titers >1:100000), with a mixed IgG1/IgG2a subclass response. Spleen cells from Co.120-immunized mice gave a significant specific proliferative response. IFN-gamma gene expression was also detected after an ex-vivo specific stimulation of spleen cells in all immunized mice. This response was independent of dose, H-2 genetic background or type of adjuvant. The results indicated that immunization with the Co.120 protein elicits a potent anti-HCV humoral and cellular immune response.

[Pregnancy outcome and the status of the newborn infant after ICSI at La Conception Hospital in Marseille]

OBJECTIVE

To evaluate obstetric outcome of pregnancies and pediatric follow-up of children born after ICSI procedure.

MATERIAL AND METHOD

Prospective study from october 1994 to September 1998 in medical assisted procreations center in La Conception hospital in Marseilles. Three hundred forty-two couples undergoing ICSI procedures.

INTERVENTIONS

analysis of pregnancy rates, prematurity rates, obstetric outcome and frequency of congenital malformations.

RESULTS

One hundred seventy-eight pregnancies have been obtained with 111 children. Multiple pregnancy rate arise 29.7%. The average term at birth in the singleton pregnancies (38.7 weeks) is higher than in the twins (35.7 weeks). The prematurity rate of delivery before 35 weeks of gestation is about 9.6%. Seven of 111 neonates was born with a congenital malformation, no cardiovascular one. One of boys presents a bilateral cryptorchidism with severe bilateral hypotrophy.

CONCLUSIONS

Our results are similar with those of others teams. Congenital malformation rates is near rates reported in others studies. However, no bilateral cryptorchidism with bilateral severe hypotrophy has been yet reported in literature.

[Morphological aspect of embryos obtained after fertilization in vitro for male factor or ICSI]

OBJECTIVE

In order to study the eventual impact on fertilization and embryo characteristics of the microinjection procedure we compared the quality of the embryos obtained by ICSI with those of in vitro fertilization with male factors (MF IVF).

MATERIAL AND METHODS

One hundred thirty-four cycles of IVF treatment (group 1) were selected with oligoasthenozoospermia according to WHO criteria with a total number of motile spermatozoa between 500,000 and 1 million. One thousand eighty-eight mature oocytes and 486 embryos were obtained. One hundred forty-three cycles of intracytoplasmic sperm injection (group 2) were performed in couples whose in vitro fertilization was imparticable because of extreme sperm impairment. One thousand one hundred forty-seven mature oocytes were injected and 626 embryos were obtained.

RESULTS

In group 1, the pregnancy rate per embryo transfer and the implantation rate were respectively 22.7% and 12.3%. In group 2, the pregnancy rate per embryo transfer was 37.1% and the implantation rate was 17%. The statistical analysis of the embryos obtained in the two different groups did not demonstrate any difference in the distribution of the more regular and less fragmented embryos (group A) and those of the more irregular and fragmented embryos (group B). No statistical difference was demonstrated in the chronology of the division of these embryos (groups 1 and 2).

CONCLUSION

The pregnancy rate by cycle and by transfer reported by ICSI (p < 0.003 and p < 0.015 respectively) could be related to a significantly higher mean number of transferred embryos (2.65 vs 2.02) in probable relation with a higher cleavage rate (p < 0.00001).

Failure of pregnancy after intracytoplasmic sperm injection with decapitated spermatozoa: case report

The case of a couple with a history of long standing primary infertility is reported in which the man presented with a decapitated sperm defect. The woman had a normal history and presented with normal clinical characteristics. The couple underwent one unsuccessful conventional in-vitro fertilization (IVF). Subsequently, embryos were obtained and transferred after assisted fertilization attempts: in all, three subzonal inseminations and four intracytoplasmic sperm injections. A total of 49 mature oocytes was injected in both studies, 25 embryos obtained and 20 embryos transferred, three of them after freezing and thawing. Despite the good embryo morphology, implantation was unsuccessful and no pregnancy occurred. The failure of implantation may have resulted from an arrest in early embryonic development related to the sperm anomaly. One hypothesis is that transferred embryos may carry a chromosomal imbalance that prevents them from progressing to the blastocyst stage. Nevertheless, we cannot exclude the possibility that the woman is responsible for the implantation failure. Co-culture associated with a further attempt could provide information regarding the ability of embryos to progress to the blastocyst stage and implant.

Ultrastructural and immunocytochemical evidences of core-particle formation in the methylotrophic Pichia pastoris yeast when expressing HCV structural proteins (core-E1)

Particulate antigens of the Hepatitis C virus (HCV) are reported for the first time by transmission electron microscopy in Pichia pastoris. The yeast was cloned to express the first 339 NH2-terminal amino acids of the HCV polyprotein (C-E1.339 polypeptide). The C-E1.339 polypeptide covers the putative 191 aa of the core protein (aa 1-191) and 148 aa of the E1 envelope antigen (aa 192-339). Virus-like particles (VLP) with diameters ranging from 20 nm to 30 nm were specifically observed in those cells expressing the HCV polyprotein. The VLP appeared along the membrane of the endoplasmic reticulum, but were fundamentally localized in vacuoles, either free or inside autophagic bodies. Clustered particles, chains of particles, high-density reticular structures, and crystalloid bodies were also detected, the last one being an orderly arrangement of particles with 20 nm diameters. The crystal-associated particles are well differentiated from the intracellular VLP because of their uniform size and shape. We argue that membrane components are retained in the architecture of the VLP, conferring to this particle certain heterogeneity. Both kinds of particles, the VLP formed after treatment with NP-40 and the crystal-associated particles, were core protein-positives. Whether they reflect mature HCV nucleocapsid or intermediary states in the viral nucleocapsid morphogenesis remains unknown. We conclude that, like mammalian cell lines, the P. pastoris yeast could be an appropriate host for the analysis of HCV polyprotein processing and, eventually, virus assembly.

[Intrauterine insemination with the husband's sperm: conclusions of five years experience]

We analyzed retrospectively 936 intrauterine insemination (IUI) cycles with husband's sperm (384 couples). Superovulation and induction monitoring occurred in the majority of cases; IUI was timed 36-40 h after ovulatory hCG. The overall pregnancy rate per cycle (PR/C) was 11.4% (107/936). Data analysis demonstrated that PR/C decreased with infertility duration, woman's age (especially after 38 years old) and number of attempts (significantly after the 4 th cycle). Superovulation (in particular by antiestrogens) and induction monitoring seemed to provide an increase in cycle pregnancy rate. Highest PR/C were observed in dysovulation and male infertility groups. In cases of sperm defects, our data showed that 2 parameters had a significant influence on pregnancy outcome: the number of motile progressive inseminated spermatozoa (> 300,000) and the spermatozoa survival rate after 24 h (> 50%). As a conclusion, intrauterine insemination can be proposed as a satisfying treatment of infertility, if precise protocol is followed and its indications well-defined.

Invertase secretion in Hansenula polymorpha under the AOX1 promoter from Pichia pastoris

A DNA fragment containing a transcription regulating region of the alcohol oxidase (AOX1) gene from the methylotrophic yeast Pichia pastoris was used in the construction of a vector for the expression of heterologous proteins in the methylotrophic yeast Hansenula polymorpha. We used this vector to clone the SUC2 gene from Saccharomyces cerevisiae into H. polymorpha yeast. The culture conditions for invertase production using a fed-batch culture were studied. More than 1.5 x 10(3) U/ml of biologically active invertase (1 g/l) were secreted to the cellular periplasmic space. The fermentative process was scaled up to 50 l. Invertase produced from H. polymorpha was glycosylated, but it contained significantly less carbohydrate than protein produced by S. cerevisiae. Using the Western-blot technique, it was observed that invertase secreted from H. polymorpha and invertase secreted from S. cerevisiae showed common antigenic determinants.

Influence of the morphological aspect of embryos obtained by in vitro fertilization on their implantation rate

In a series of 500 transfers of embryos obtained by in vitro fertilization, we examined the implantation rate of 1356 embryos transferred in utero. The average implantation rate per embryo was 15.1% and remained relatively constant, regardless of the number of transferred embryos per patient. The implantation rate per embryo, in relation to its morphology, was clearly lower when irregular blastomeres and fragments were present in the perivitelline area. Other embryos, regardless of their morphology, had an identical development potential. Analysis of the results of this series demonstrates the difficulty of determining the development potential of all the embryos on the basis of morphological criteria.

Epididymal sperm aspiration in conjunction with in-vitro fertilization and embryo transfer in cases of obstructive azoospermia

Epididymal sperm aspiration is a new treatment for vasal agenesis. In previous reports, epididymal spermatozoa resulted in pregnancy by utilizing in-vitro fertilization (IVF) or gamete intra-Fallopian transfer (GIFT). We sought to investigate the efficacy of epididymal sperm aspiration in conjunction with IVF in patients with congenital absence of the vas deferens or with secondary extended obstruction of spermatic ducts. Fifty-eight attempts were performed in 23 patients (25-50 years). Eight patients (34.7%) had vasal agenesis and 14 (60.8%) presented with vasal secondary extended obstruction. The sperm count was adequate (greater than or equal 20 x 10(6)/ml) in 13.8% of sperm retrievals and sperm motility of 20% was obtained in 15.5% of sperm retrievals. Fourteen attempts at IVF were performed with epididymal sperm counts of 2-44 x 10(6)/ml and motilities of 0-45%. A mean of six mature oocytes (0-13) were inseminated in each case. Five embryo transfers were performed in five patients' wives (35.7%) and two couples had an early pregnancy loss (14.2%). Epididymal sperm aspiration is an advance in treating such patients, as an adequate number of mature spermatozoa can be obtained and used for IVF. However, spermatozoa directly aspirated from the proximal epididymis and with fertilizing capacity in vitro, gave a high rate of embryo degeneration (greater than 50%) after embryo transfer.

[Incidence of the morphological aspect on the rate of implantation of embryos obtained by fertilization in vitro]

1350 embryos obtained by In Vitro Fertilization (IVF) have been examined with the reverse microscope before their transfer in utero. Some embryos are "morphologically normal" (34.7%); some others are atypical. It is difficult to determinate the implantation rate by embryo according to morphological aspect because, most of the time we transfer several embryos to only one patient and we do not know, in case of pregnancy, which one or which ones have developed. Nevertheless, we have tried to appreciate, for 500 embryos transfers after IVF, the incidence of morphological aspect according to the presence or absence of "morphologically normal" embryos. The implantation rate is significantly higher in the groups in which you find "morphological normal" embryos than in the group where they are missing. (19.7% and 19.2% vs 10.2%). It seems that the aspect of the embryo when it is transferred, has an incidence on its future development.

Nucleolar changes in human embryo during the pre-implantation stage. Activation of ribosomal genes during the nucleologenesis

We studied the structural and functional organization of human embryo nucleoli during the pre-implantation stage from spare embryos obtained by in vitro fertilization. In human embryo nucleoli, structural modifications occur during the first cleavages. They lead to the constitution of a reticulated nucleolus from an initial structure called primary nucleolus. They appear during the third cleavage and correspond to the nucleogenesis. Autoradiography shows no transcription in the primary nucleolus. Transcription of rDNA starts on the periphery of the initial structure after the 4-cell stage. It corresponds to the beginning of the embryonic gene expression. The entire nucleolus will be progressively concerned by this transcription during the reticulation. Silver staining at the ultrastructural level shows that Ag-NOR proteins are missing in the primary nucleolus. In the beginning of nucleogenesis, Ag-NOR proteins are first located on the nucleolar periphery. Their following distribution corresponds to the structures containing rDNA in the nucleolus. Nucleologenesis in the human embryo during the pre-implantation stage first requires an association of rDNA with a primary structure, then an activation of ribosomal genes.

[Estimation of the quality of embryos obtained during fertilization in vitro as a function of their morphology]

Embryo quality after IVF should allow provisions for their pregnancy potential. We have classified all the transferred embryos into 4 types according to morphological criteria and we have studied the implantation rate of the different types. The results show: That pregnancies have been obtained with the 4 types of embryos. That it has been impossible to demonstrate statistically significant differences between the different types of transferred embryos even if embryos morphologically normal seem to be more favourable than others to induce a pregnancy. That the average implantation rate for each transferred embryo is of 14.4%.

[Effects of electric stimulation of the para-ventricular nucleus on corticotropin function in Long-Evans and Brattleboro rats]

Two peptides have a strong corticotropin releasing factor (CRF) activity: arginine vasopressine (AVP) and a 41-residue peptide (41-CRF). Both peptides are present in high concentration in the PVN of the Rat, a zone of the hypothalamus at which electrical stimulation elicits ACTH release. Since homozygous Brattleboro Rats (Di/Di) congenitally lack endogenous AVP, it was of interest to compare the ACTH and corticosterone release after electrical stimulation of the PVN in Long-Evans (L.E.) and Di/Di Rats. In both L.E. and Di/Di Rats, there is a significant increase in plasma ACTH and corticosterone after electrical stimulation of the PVN. However, corticosterone levels are significantly lower in Di/Di than in L.E. Rats whether the Rats have been stimulated or not. It is concluded that a physiological CRF activity is present in the PVN of Di/Di Rats independently of the CRF like activity of AVP.

[Effects of the injection of kainic acid into the medial hypothalamus on the secretion of corticolipotropic hormones in the rat]

alpha-MSH secretion was significantly lowered in Rats after lesion of the mediobasal hypothalamus with microinjections of kainic acid. beta-Endorphin release after ether-stress was also reduced. In opposition, no significant change in basal and ether-stress ACTH secretion was observed.

[Ultrastructure of the rat neurohypophysis following electric stimulation of the supraoptic nuclei]

By means of electrical stimulation of the supraoptic nuclei, in a stereotaxic apparatus, partial or complete degranulation of the neurohypophysis is obtained, with often a continued presence of large vesicles; the number of microvesicles is always increased.