Validation of the motivational phase of the integrated motivational-volitional model of suicidal behavior in a German high-risk sample

BACKGROUND

The Integrated Motivational-Volitional (IMV) model of suicidal behavior proposes in its motivational phase that perceptions of defeat and entrapment (total, internal and external entrapment) lead to the development of suicidal ideation and that thwarted belongingness and perceived burdensomeness moderate this process. The aim of this study was to test the motivational phase of the IMV model cross-sectionally in a German sample of psychiatric inpatients.

METHODS

A total of 308 psychiatric inpatients (53% female) aged 18 to 81 years (M = 36.92, SD = 14.30) were included in the study and investigated within 14 days after psychiatric admission due to suicide attempt (53%) or acute suicidal crisis (47%). Statistical analyses included a mediation analysis and moderation analyses.

RESULTS

Results demonstrate a simple mediation of defeat via entrapment (total, internal and external entrapment) on suicidal ideation. The interaction between thwarted belongingness and perceived burdensomeness was confirmed as a motivational moderator.

LIMITATIONS

Limiting factors of the present study are the cross-sectional design and the retrospective assessment of suicidal ideation.

CONCLUSION

The main assumptions of the motivational phase of the IMV model could empirically be confirmed. Perceptions of defeat, internal and external entrapment, thwarted belongingness, and perceived burdensomeness should be taken into account with regard to prevention, risk assessment and interventions of suicidal ideation and attempts. However, future investigations based on prospective data are warranted.

[Long-term outcome after dialysis-dependent renal failure on the intensive care unit]

Hintergrund

Das akute dialysepflichtige Nierenversagen („dialysis-requiring acute kidney injury“ [AKI‑D]) ist eine häufige und schwerwiegende Komplikation bei intensivmedizinisch behandelten Patienten.

Fragestellung

Im Rahmen dieser Studie sollte untersucht werden, welchen Einfluss ein AKI‑D auf die Sterblichkeit von Intensivpatienten besitzt, bei welchem Anteil der überlebenden Patienten auch bei Entlassung noch ein Nierenersatzverfahren benötigt wird und wie sich dies auf die Langzeitmortalität und die längerfristige Notwendigkeit einer Dialysetherapie auswirkt.

Material und Methoden

Auswertung von 118 Patientenfällen mit AKI‑D zwischen November 2016 und Dezember 2017 auf einer internistischen Intensivstation am Universitätsklinikum Tübingen. Die Dialysefreiheit zum Entlasszeitpunkt und die 1‑Jahres-Mortalität wurden als primäre Endpunkte definiert. Den sekundären Endpunkt stellte die Dialysepflichtigkeit nach 18 Monaten dar.

Ergebnisse

Die Krankenausmortalität der Patienten mit AKI‑D betrug 45,8 % (54/118). Von den 64 überlebenden Patienten mit AKI‑D waren 41 (64,1 %) zum Zeitpunkt der Entlassung nicht mehr auf ein Nierenersatzverfahren angewiesen. Im Vergleich dazu war die 1‑Jahres-Mortalität bei den 23 (35,9 %) Patienten, bei denen zur Krankenhausentlassung noch eine Dialysepflicht bestand, signifikant höher (24,4 % vs. 60,9 %, p = 0,004). Eine Dialysepflichtigkeit 18 Monate nach Krankenhausentlassung bestand bei 7 Patienten (10,9 %). Zu diesem Zeitpunkt waren überwiegend noch Patienten von einer Dialyse abhängig, bei denen bereits zum Entlasszeitpunkt ein Nierenersatzverfahren notwendig war (71,4 % vs. 7,1 %, p = 0,001).

Schlussfolgerungen

Schwere AKI-Episoden, bei denen ein Nierenersatzverfahren auf einer Intensivstation notwendig wird, sind auch 1 Jahr bzw. 18 Monate nach Entlassung mit einer erhöhten Mortalität bzw. einer anhaltenden Dialysepflichtigkeit assoziiert.

Global transcriptomic response of bovine endometrium to blastocyst-stage embryos

The aims of this study were (i) to investigate changes in the global transcriptome of bovine endometrial explants induced by exposure to blastocysts, (ii) to investigate if male and female blastocysts elicit a differential response in the endometrial transcriptome in vitro and (iii) to determine whether bovine endometrium responds to the presence of murine embryos. In Experiment 1, endometrial explants from the same uterus were cultured for 6 h with or without 20 in vitro-produced bovine blastocysts. In Experiment 2, endometrial explants were cultured with male or female bovine blastocysts produced in vitro by IVF either using sex-sorted semen or conventional unsorted semen followed by embryo sexing based on a biopsy. In Experiment 3, endometrial explants were cultured alone or in the presence of bovine blastocysts (n = 25) or murine blastocysts (n = 25). Following culture, explants were snap frozen and stored at -80°C until RNA extraction, qPCR or RNA-Seq. Culture with bovine blastocysts increased endometrial expression of 40 transcripts, all of which were interferon-tau induced. Culture with male or female bovine blastocysts increased transcript abundance of five classic interferon-stimulated genes (MX1, MX2, ISG15, OASY1, RSAD2) in explants; however, there was no difference in abundance of transcripts previously reported to be related to embryonic sex (IFNAR1, IFNAR2, CTGF, ARTN, SLC2A1, SLC2A5). Exposure to murine blastocysts did not elicit any detectable change in transcript abundance. These findings, coupled with our previous data, indicate that very local, interferon-tau-induced changes in endometrial gene expression occur in response to blastocysts; whether such changes play any role in subsequent pregnancy recognition remains to be established.

P3641Matrix Metalloproteinase-2 polymorphisms are associated with prognosis of patients with symptomatic coronary artery disease

Background

Matrix Metalloproteinase-2 (MMP-2) is involved in regulation and proliferation of vascular and endothelial cells and is therefore an important component of atherosclerotic vessels. Inhibition of MMP-2 activity is associated with improvement of cardiac function in animal models after myocardial infarction. MMP-2 single nucleotide polymorphisms (SNPs) might alter MMP-2 expression and therefore influence prognosis in patients with symptomatic coronary artery disease (CAD).

Methods and results

Genotyping for selected MMP-2 SNPs variants (rs2241145, rs2285053, rs2287076, rs243865, rs7201) was performed in 943 consecutive patients with symptomatic CAD. All patients were followed-up for all-cause death (ACD), myocardial infarction (MI) and ischemic stroke (IS) for 360 days. The primary combined endpoint (CE) consisted of either first occurrence of ACD, and/or MI, and/or IS. Secondary endpoints were defined as the single events of ACD or MI. Homozygous carriers of major allele (rs2241145, rs2287076) showed significantly better event-free survival than carriers of the minor allele for CE (Log rank = 0.022 and Log rank= 0.015, respectively). Furthermore, homozygous carriers of major allele (rs2241145, rs2285053, rs2287076) showed significantly better event-free survival for ACD (Log rank= 0.047, Log rank= 0.006 and Log rank= 0.023, respectively). In multivariate analysis, MMP-2 rs2241145, rs2287076 and rs2285053 were significantly and independently associated with CE and ACD.

Figure 1

Conclusions

MMP-2 rs2241145, rs2287076 and rs2285053 are associated with prognosis and might be valuable for further risk stratification in CAD patients.

Acknowledgement/Funding

DFG, KFO 274, CRC TR 240

P3643Junctional Adhesion Molecule-A (JAM-A) polymorphisms influence serum levels of soluble JAM-A and are associated with long term prognosis in coronary artery disease

Aims

Junctional adhesion molecule A (JAM-A/F11R) is a cell adhesion molecule. Membrane associated JAM-A mediates platelet aggregation, secretion, adhesion, and spreading. Plasma levels of JAM-A are elevated in hypertension and atherosclerosis. This study was designed to investigate the impact of JAM-A single nucleotide polymorphisms (SNPs) on circulatory JAM-A levels and prognosis in patients with symptomatic coronary artery disease (CAD).

Methods and results

JAM-A SNP analysis (JAM-A F11R rs2774276 and rs790056) was performed in 943 patients with symptomatic CAD. All patients were tracked for all-cause death (ACD), myocardial infarction (MI), and ischemic stroke (IS) for 1080 days. The primary combined endpoint (CE) was defined as a composite of ACD and/or MI and/or IS. Secondary endpoints were defined as the single events of ACD and MI. Homozygote carriers of the minor allele (F11R rs2774276 and rs790056) showed significantly worse event-free survival for MI when compared with major allele carriers (Log rank = 0.011 and log rank = 0.031, respectively). No significant differences could be shown for the CE and ACD. Of note, in multivariate analysis, both SNPs were significantly and independently associated with MI. Furthermore, serum levels of soluble JAM-A were elevated in homozygote carriers of minor allele when compared to major allele carriers. Finally, serum levels of soluble JAM-A were significantly elevated in patients with MI when compared to stable CAD (p=0.036).

Figure 1

Conclusion

JAM-A SNPs are associated with prognosis in patients with symptomatic coronary artery disease. Furthermore, JAM-A SNPs might influence serum concentration of soluble JAM-A. Finally, serum concentration of soluble JAM-A is higher in patients with myocardial infarction when compared to stable coronary artery disease. These findings suggest JAM-A as a valuable biomarker for risk stratification and tailoring therapies in patients with coronary artery disease.

Acknowledgement/Funding

DFG-KFO274, CRC/Transregio 240

P840Predicting outcome in patients with symptomatic coronary artery disease: A comparison of available risk assessment scores

Introduction

Thromboischemic and bleeding events are rare but potentially life-threatening complications after percutaneous coronary intervention (PCI). Consequently, duration of dual antiplatelet therapy (DAPT) after coronary stent implantation might be altered due to bleeding or thromboischemic risk. Various risk assessment models have been established to predict adverse events in patients with symptomatic coronary artery disease (CAD). The aim of the present study was to compare available scoring systems based on their performance identifying high-risk patients with symptomatic CAD.

Methods and results

1469 patients were included (n=730 stable CAD and n=739 acute coronary syndrome (ACS)). GRACE 2.0, CALIBER, PREDICT-STABLE, PARIS MB, PARIS CTE and DAPT scores were calculated in appropriate patient subgroups. All patients were followed-up for 360 days for all-cause death (ACD), myocardial infarction (MI), ischemic stroke (IS) and bleeding. The primary combined endpoint (CE) consisted of ACD, MI and/or IS. Secondary endpoints were defined as single occurrence of either ACD, MI, IS, or bleeding. Strong discrimination performance for ACD (AUC=0.82) and IS (AUC=0.84) could be shown for PARIS-MB and CALIBER score, respectively. For ACD, good discrimination performance was found for GRACE (AUC=0.79), CALIBER (AUC=0.71), PARIS-CTE (AUC=0.71) and PREDICT-STABLE (AUC=0.70) score, respectively. For CE and bleeding, we could demonstrate good discrimination performance for GRACE (AUC=0.71) and CALIBER (AUC=0.76) score.

Figure 1

Conclusions

In short-term follow-up, several risk assessment models show strong to good discrimination performance for major adverse cardiovascular events. These prediction models might be used to adjust duration of DAPT in patients with symptomatic CAD.

Acknowledgement/Funding

DFG, KFO-274, SFB-TRR 240

Predicting suicidal ideation by interpersonal variables, hopelessness and depression in real-time. An ecological momentary assessment study in psychiatric inpatients with depression

OBJECTIVE

To extend evidence on the short-term variability of passive and active suicidal ideation (SI) and the association with suggested proximal risk factors such as interpersonal variables (perceived burdensomeness [PB], thwarted belongingness [TB], hopelessness, and depression) in real-time.

METHODS

This is an observational study using a prospective design applying ecological momentary assessments (EMA). Eligible for study inclusion were inpatients with unipolar depression, current or lifetime suicidal ideation, and fluent German. Over six days, 74 participants rated their momentary level of passive and active SI, PB, TB, depressiveness, and hopelessness up to 10 times per day on smartphones. Data was collected from August 2015 to July 2017. Compliance was excellent (89.7%).

RESULTS

Mean squared successive differences supported temporal instability for all variables. According intra-class correlations, between 25% and 47% of variance was accounted for by within-person variability. Multilevel analysis demonstrated significant positive associations between hopelessness, depressiveness, PB, and TB with passive SI. Prospectively, hopelessness and PB remained predictors of passive SI. For active SI, hopelessness, depression, PB, and TB were significantly associated cross-sectionally. Prospectively, hopelessness, PB, and the interaction PBxTB predicted active SI. All models were controlled for previous level of SI.

CONCLUSIONS

This study provides further evidence on the short-term variability of SI in very short time frames implying the need of assessing SI repeatedly in clinical and research settings. The associations between interpersonal variables and passive and active SI were only partial in line with assumptions of the Interpersonal Theory of Suicide. Overall, the effects were small warranting further investigation.

Single layer colloid centrifugation technique improves motility, viability and chromatin integrity of ram spermatozoa after thawing

The cell membrane of ram spermatozoa is more sensitive to the freezing process than in other species due to its composition. As a result, the quality and viability of frozen thawed ram spermatozoa are often poor, which together with the specific structure of the ewe's cervix are the main reasons for lower fertility in ewes after intracervical insemination. In the present study we investigated the effects of semen centrifugation through a single layer of a species-specific colloid (Androcoll-O) on post-thaw quality of ram spermatozoa. Motility, viability and morphology were analysed 0, 6, 12 and 24 h after thawing. DNA fragmentation index (%DFI) of the samples was assessed 0 h after thawing, by SCSA™. Membrane and acrosome integrity of spermatozoa were analysed by Sybr-14/PI/PNA test 0 h after thawing. The proportion of motile spermatozoa was significantly higher in SLC - selected samples in comparison to control (not SLC - selected) samples at 0, 6, 12 (P < 0.001) and 24 h (P < 0.05). The proportion of viable spermatozoa was also significantly higher in SLC - selected samples in comparison to control samples at all times (P < 0.001). The proportion of abnormal acrosomes and morphologically abnormal spermatozoa (MAS) were significantly lower in SLC - selected samples compared to control samples at all times (P < 0.001). Analysis of chromatin stability revealed significantly lower %DFI values in SLC - selected samples compared to control samples (P < 0.001). The SYBR-14/PI/PNA test also revealed significantly better values in SLC - selected compared to control samples (P < 0.05). In conclusion, single layer colloid centrifugation significantly improved post-thaw quality and longevity of ram spermatozoa, making it suitable for artificial insemination initiatives.

Triplex-hybridizing bioconjugated gold nanoparticles for specific Y-chromosome sequence targeting of bull spermatozoa

Gold nanoparticles (AuNPs) are widely used in biomedical applications for drug targeting and bioimaging. This often neccesitates their functionalization with biomolecules carrying a defined biological function, yielding gold nanoparticle bioconjugates. The utilization of triplex-forming oligonucleotides (TFOs) as ligands gives access to nanoconjugates as tools for specific DNA-related nanotargeting via triplex hybridization. Since triplex hybridization with nanobioconjugates has to date not been shown on biologically relevant samples, sex-specific sperm marking may be an appropriate model system to demonstrate the opportunities of this targeting method in vitro. In this study, we focused on specific labeling of repetitive target sites enriched on the bovine Y-chromosome using triplex forming oligonucleotides. First, the functionality of a specific locked nucleic acid (LNA) sequence was confirmed on bovine free DNA and on demembranated sperm heads. Thereafter, the influence of AuNPs on triplex hybridization was spectrophotometrically analyzed employing synthetic dsDNA, genomic DNA and demembranated sperm heads. Results from the SPR-peak shift indicate that TFO-AuNP hybridize to bovine gDNA in a qualitative and significant manner. These results confirm successful triplex hybridization on biologically relevant target sites as well as the establishment of a method to use gold nanoparticles as a suitable tool for sex-selective hybridization.

Sex-Sorted Boar Sperm - An Update on Related Production Methods

As in other mammals, sex sorting of pig sperm is based on quantitative flow cytometry. A major disadvantage of the technique is the relatively low efficiency to produce enough sorted sperm for artificial insemination. However, several approaches are on the way to make sexed pig sperm available for commercial application. In this context, for example, the growing field of nanotechnology may significantly contribute to these developments, as it provides highly efficient bio-nanoprobes, for example, based on plasmonic nanoparticles. Independent of the method, further development requires enormous investments and set-up of logistics to get the technology into the practical pig market. Only global players will be able to establish the necessary research projects, but in the end, a significant shift of sex ratios will be available for pig producers as it is already the case for the dairy industry.

Platelet surface expression of stromal cell-derived factor-1 receptors CXCR4 and CXCR7 is associated with clinical outcomes in patients with coronary artery disease

BACKGROUND

Surface expression of stromal cell-derived factor-1 (SDF-1, CXCL12) on platelets is enhanced during ischemic events and plays an important role in peripheral homing of stem cells and myocardial repair mechanisms. SDF-1 effects are mediated through CXCR4 and CXCR7. Both CXCR4 and CXCR7 are surface expressed on human platelets and to a higher degree in patients with coronary artery disease (CAD) compared with healthy controls. In this study, we investigated the prognostic role of platelet CXCR4- and CXCR7 surface expression in patients with symptomatic CAD.

METHODS AND RESULTS

In a cohort study, platelet surface expression of CXCR4 and CXCR7 was measured by using flow cytometry in 284 patients with symptomatic CAD at the time of percutaneous coronary intervention (PCI). The primary combined end point was defined as all-cause death and/or myocardial infarction (MI) during 12-month follow-up. Secondary end points were defined as the single events of all-cause death and MI. We found significant differences of CXCR4 values in patients who developed a combined end point compared with event-free patients (mean MFIAUTHOR: Please define MFI at first use. 3.17 vs. 3.44, 95% confidence interval [CI] 0.09-0.45) and in patients who subsequently died (mean MFI 3.10 vs. 3.42, 95% CI 0.09-0.56). In multivariate Cox regression analysis, lower platelet CXCR4 levels were independently and significantly associated with all-cause mortality (hazard ratio 0.24, 95% CI 0.07-0.87) and the primary combined end point of all-cause death and/or MI (hazard ratio 0.30, 95% CI 0.13-0.72).

CONCLUSION

These findings highlight a potential prognostic value of platelet expression CXCR4 on clinical outcomes in patients with CAD.

Comparison of 68Ga-DOTATOC biodistribution in patients with and without spleenectomy

AIM

Ga-68 labeled somatostatin analogues such as 68Ga-DOTA0-Phe1-Tyr3-octrotide (DOTATOC) as PET tracers, have significantly improved the imaging of somatostatin receptors (SSTRs) expressing tumors. Due to unspecific parenchymal binding and the expression of SSTRs on leukocytes in the spleen this is the organ with the highest non-tumor uptake of DOTATOC. Therefore, we investigated the potential changes of normal tissue distribution and tumor concentration in patients with neuroendocrine tumors (NETs) with or without spleenectomy.

METHODS

Out of 420 patients with pancreatic NET undergoing 68GA-DOTATOC PET/CT eleven patients with and eleven patients without spleenectomy were derived and matched in regard to tumor histology, tumor load, age and gender. The SUV(max) of liver metastases as well as of the following normal tissues was determined: pituitary gland, thyroid gland, liver parenchyma, kidneys and suprarenal glands.

RESULTS

SUV(max) values with and without spleenectomy were: in the liver metastasis (19.17 ± 6.05 versus 37.67 ± 16.31), in the thyroid gland (2.56 ± 1.33 versus 2.66 ± 0.94), in the pituitary gland (4.08 ± 1.79 versus 4.92 ± 1.93) in suprarenal glands (7.18 ± 3.33 versus 9.73 ± 3.46 on the left side and 7.32 ± 3.03 versus 11.19 ± 5.72 on the right side), in the kidneys (8.1 3 ± 4.26 on the left side and 8.11 ± 4.16 on the right side versus 8.62 ± 2.17 on the left side and 9.79 ± 2.18 on the right side) and in normal liver tissue (5.74 ± 1.55 versus 6.22 ± 1.95). The difference was statistically significant (Wilcoxon test P<0.05) in tumor lesions, adrenal and kidney tissue.

CONCLUSION

Spleenectomy must be considered as a relevant factor when reporting the outcome of SSTR targeted diagnostics and therapies.

Impact of metal nanoparticles on germ cell viability and functionality

Metal nanoparticles play an increasing role in consumer products, biomedical applications and in the work environment. Therefore, the effects of nanomaterials need to be properly understood. This applies especially to their potential reproductive toxicology (nanoreprotoxicity), because any shortcomings in this regard would be reflected into the next generation. This review is an attempt to summarize the current knowledge regarding the effects of nanoparticles on reproductive outcomes. A comprehensive collection of significant experimental nanoreprotoxicity data is presented, which highlight how the toxic effect of nanoparticles can be influenced, not only by the particles' chemical composition, but also by particle size, surface modification, charge and to a considerable extent on the experimental set-up. The period around conception is characterized by considerable cytological and molecular restructuring and is therefore particularly sensitive to disturbances. Nanoparticles are able to penetrate through biological barriers into reproductive tissue and at least can have an impact on sperm vitality and function as well as embryo development. Particularly, further investigations are urgently needed on the repetitively shown effect of the ubiquitously used titanium dioxide nanoparticles on the development of the nervous system. It is recommended that future research focuses more on the exact mechanism behind the observed effects, because such information would facilitate the production of nanoparticles with increased biocompatibility.

10 SPERM BINDING TO PORCINE UTERINE EPITHELIAL CELLS MIGHT BE LECTIN MEDIATED

Evidence suggests that porcine spermatozoa bind to the endometrium lining after entering the uterus. In previous studies, it was verified that this binding is specific to porcine uterine epithelial cells (UEC). Here, we present trials aimed at identifying the engaged binding mechanism. Several interactions of spermatozoa with the female reproductive tract are known to be lectin mediated. The respective sugar ligands are species specific for the oviductal as well as zona pellucida surface membrane. Therefore, we hypothesised that sperm-endometrium interactions are mediated by lectins, too. To block possibly existing sugar moieties on the sperm surface, we pre-incubated spermatozoa with lectins selected for their strong binding to viable spermatozoa [wheat germ agglutinin WGA, succinylated WGA (sWGA), concanavalin A (ConA)] and subsequently undertook co-incubation studies using an established cell culture model from primary porcine uterine epithelial cells. All trials were carried out in modified Dulbecco’s Modified Eagle’s Medium containing 20% serum (D20) because the UEC monolayer proved to react sensitive to PBS as well as to semen extender. Pre-trials confirmed that in D20 sperm vitality remained unaffected and lectin binding efficiency did not differ compared with PBS. The sperm-rich fraction of the ejaculate from 3 German Landrace boars was collected in D20 and washed by centrifugation. The pellet was resuspended in D20 and the concentration adjusted to 100 × 106 spermatozoa mL–1. Then, the samples were incubated with 1 of the 3 lectins (10 µg mL–1) for 15 min at 37°C. As a control, 1 aliquot of the sperm suspension was incubated without lectins. After another washing step, the pellet was resuspended in D20. For co-incubation with UEC, 500 µL of lectin-incubated sperm was released onto a UEC monolayer and the binding activity observed under a phase contrast microscope. The binding density was quantified by area under view and compared to results from the control incubation with untreated sperm. Images (2 repeats/boar and lectin) were divided into fields of 61.6 µm2 and the fields with and without sperm were counted. For statistical analysis, a Tukey Test was carried out. Sperm treated with WGA and sWGA, both binding to glucosamine molecules, showed significantly reduced binding activity to the UEC (P < 0.05), whereas ConA-treated and untreated sperm bound in the dense pattern as shown in previous trials. The results indicate that the sperm-UEC binding mechanism is mediated by glucosamine moieties on the sperm surface, which interact with matching lectins placed on the UEC membrane surface. Investigations for further confirmation of the suggested binding mechanism between porcine sperm and the uterine epithelial layer are ongoing. Supported by IMV Technologies, L’Aigle, France.

Sex selection of sperm in farm animals: status report and developmental prospects

Pre-selection of spermatozoa based on the relative DNA difference between X- and Y-chromosome bearing populations by flow cytometry is an established method that has been introduced into commercial cattle production. Although several important improvements have increased the sort efficiency, the fertilising ability of sexed spermatozoa based on offspring per insemination is still behind farmers' expectations. The main stress factors, especially on mitochondria, that reduce the lifespan of spermatozoa are described, and new technical as well as biological solutions to maintain the natural sperm integrity and to increase the sorting efficiency are discussed. Among these methods are the identification of Y-chromosome bearing spermatozoa by bi-functionalised gold nanoparticles and triplex hybridisationin vivoas well as new laser-controlled deflection system that replaces the deflection of spermatozoa in the electrostatic field. Additionally, as well as a new nonsurgical transfer system of spermatozoa into the oviduct of cows has been developed and allows a significant reduction of spermatozoa per transfer. Altogether, the improvements made in the recent years will allow a broader use of sex-sorted spermatozoa even in those species that require more cells than cows and sheep.

149 UNIMPAIRED DEVELOPMENT OF MURINE EMBRYOS AFTER INJECTION OF SILVER NANOPARTICLES

Because of their antibacterial properties, silver nanoparticles (AgNP) are used abundantly in medical products such as wound dressing and catheters, but also in consumer items like clothing and lining of food containers. Despite such widespread exposure and the fact that they are considered toxic to eukaryotic cells as well, knowledge concerning their reprotoxic potential is very limited. Therefore, the aim of the present study was to investigate the effects of AgNP on embryo development. The used AgNP were produced by laser ablation in liquids, which provides particles of high purity and stability. In order to ensure direct contact of the particle with the developing organism, 10 pL of an AgNP-dispersion in water (250 µM Ag; average particle diameter 15 nm) was microinjected into one blastomere of a two-cell-stage embryo (n = 91), derived from superovulated NMRI-mice. As controls, embryos were injected with water only (n = 74) or left untreated as a handling control (n = 102). Subsequently, in vitro culture commenced for 72 hours at 37°C and 5% CO2 in KSOM plus 1% BSA. In order to distinguish whether possible effects are caused by the nanoparticles as such or by Ag+-ions released from the nanoparticles, additional embryos were co-incubated with silver nitrate (25 µM) during culture (n = 41). To exclude influence of the NO–-ions on the embryo development, potassium nitrate controls (25 µM) were run as well (n = 40). The obtained blastocyst rates were compared using one-way ANOVA and a chi-square test. Day 4 blastocysts derived from the injected groups and the handling control were used for a real-time PCR analysis, to investigate gene expression of developmentally important genes (Bax, Bcl2l2, and Tp53 for apoptosis; Oct4 and Nanog for stemness, Dnmt3a for methylation). Embryo development was assessed on a daily basis. In the injected embryos, no abnormal development was observed. After injection with silver nanoparticles, the development rate reached 61.5%, which did not differ from the water-injected embryos, where 66.2% of the embryos developed to blastocysts. The handling controls reached a significantly higher blastocyst rate of 79.4% compared to both injected groups (P < 0.05). Interestingly, gene expression remained unaltered regardless of whether embryos were injected with AgNP, water, or not injected at all. Exposure to Ag+-ions resulted in an immediate arrest of development, while co-incubation of embryos with KNO showed no effect, reaching a blastocyst rate of 80.0%. In conclusion, the results do not indicate any negative effect of intracytoplasmatic injection of silver nanoparticles on murine embryos. Since the presence of Ag+-ions was shown to have a tremendously detrimental effect on the development, the nanoparticles do not seem to release silver ions in amounts sufficient to disturb this delicate process. Further studies involving gametes and embryos of large animal models are ongoing to intensify our understanding of silver nanoparticle reprotoxicity. Supported by DFG Grant SPP1313 and REBIRTH.

329 FLOW CYTOMETRIC ANALYSIS OF SPERMATOZOA FROM REPORTER TRANSGENIC BOARS DERIVED BY PRECISION GENETIC ENGINEERING

Recently, we produced 2 founder boars with a non-autonomous Sleeping Beauty (SB) system carrying 3 monomeric integrations of a Venus transposon cassette and showing transgene segregation during meiosis (Garrels et al. 2011 PLoS One 6, e27563). It was possible to show transmission of the reporter protein to fertilized oocytes by confocal microscopy. The aim of this study was to assess the suitability of different fluorophore reporters for in vivo labelling of pig spermatozoa. Therefore, we used Venus transposon fibroblasts from a F1 boar, which carry a single integration of the transposon cassette and used these fibroblasts for a Cre-mediated cassette exchange against an mCherry reporter. These cells were used for somatic cell nuclear transfer (SCNT) to derive a syngene clone cohort of boars, which differ only in the fluorophore reporter cDNAs (either Venus or mCherry). Importantly, this methodology did not request any antibiotic selection cassette and allows precise genetic modifications in a livestock species where no authentic embryonic stem cells are available (Garrels et al. 2012 Trends in Biotechnology 30, 386–393). A total of 8 male piglets carrying the Venus transposon, and 4 male piglets carrying the mCherry reporter were born. Three Venus boars and 2 mCherry boars were raised to sexual maturity, and ejaculated sperm was obtained with the help of a phantom. A detailed flow cytometric analysis revealed that the spermatozoa samples were specifically Venus or mCherry positive [Gallios, Beckmann Coulter, Krefeld, Germany; solid-state laser (488 nm; 22 mW), filter for green fluorescence (525 BP); filter for red fluorescence: (620/30)], respectively. In direct comparative measurements, the spermatozoa samples from transgenic boars (Venus and Cherry) and wildtype controls could be discriminated. Interestingly, spermatozoa were uniformly Venus- or mCherry-positive and gave a distinct fluorescence peak in flow-cytometric measurements. The monomeric transgenes were transmitted through the germ line according to Mendelian rules with the expected ratio of 50% transgenic and 50% nontransgenic piglets. Fluorescence microscopic analysis and Western blotting confirmed the uniform presence of Venus and mCherry in boar spermatozoa, respectively. This is the first characterisation of spermatozoa from a pig cohort carrying a targeted cassette exchange. This large animal model may help to elucidate the function of paternally transmitted components to fertilized oocytes.

25 TIMED ARTIFICIAL INSEMINATION ENABLES HIGH FERTILIZATION RATES IN NORMAL CYCLING AND IN SUPEROVULATED CATTLE WITH REDUCED DOSAGES OF UNSORTED SPERMATOZOA AND WITH SEXED SPERMATOZOA

Different factors determine the effectiveness of the use of sires in AI. Most important factors are the number of inseminated spermatozoa, the quality of spermatozoa, and the time of insemination. Especially in superovulated animals, the insemination scheme plays in important role to cover the whole ovulation period. The influence of 3 different dosages of spermatozoa (15 × 106, 5 × 106, and 1 × 106) on fertilization rate was examined in experiment A. In experiment B, one dosage of female and male spermatozoa of 3 different bulls was used for timed AI in 31 heifers. Timed AI in normal-cycling cattle [13 h after gonadotropin-releasing hormone (GnRH) application] with detected corpus luteum (Days 8 to 13 of cycle) was carried out after induction of luteolysis and induction of ovulation [GnRH application 60 h after prostaglandin F2α (PGF2) application]. Embryos and oocytes were flushed from the oviduct of 116 hemicastrated or slaughtered heifers on Day 4 after insemination. The ovulation rate in heifers was 95.4%. Eighty percent of the oocytes or embryos were recovered. The influence of the factors sire, ejaculate, and dosage were tested by GLM analyses of SAS® (SAS Institute Inc., Cary, NC, USA). There was no significant difference in the fertilization rate (93.3, 96.2, and 78.8%) and in the proportion of normally developed embryos (84.6, 80.7, and 75.8%) between groups. Significant differences were found in the mean number of accessory sperms/embryo and in the proportion of embryos with >10 accessory sperms/embryo or without accessory sperms; however, the proportion of intact embryos was similar. Using sexed semen in experiment B, similar results were obtained after flushing of the oviducts on Day 4 after insemination of hemicastrated or slaughtered animals. In total, an ovulation rate of 91.7%, a recovery rate of 70%, and a fertilization rate of 86.8% were obtained. There were no differences between female- and male-sorted spermatozoa and the control group. In experiment C, altogether 13 heifers were treated 8 times with FSH for 4 days starting between Day 8 to 12 of estrous cycle. Prostaglandin F2α was given 48 and 60 h after the first FSH injection. Insemination with sexed semen (n = 5 heifers) and with unsorted semen (n = 8; 15 × 106 and 1 × 106) was done at 55 and 71 h after induction of luteolysis. Flushing of the uterus was performed on Day 7. Using the time-oriented insemination after superovulation of animals, fertilization rates varied between 65 and 85%. There was no difference between groups regarding the number of transferable embryos (5.5, 4.9, and 4.8). The results demonstrate that the application of an approved insemination schedule may accomplish high fertilization rates after insemination with sexed or reduced dosages of spermatozoa in normal-cycling as well as superovulated cattle.

Experiments to improve in vitro fertilization techniques for in vivo-matured porcine oocytes

Three experiments were designed for the in vitro fertilization of in vivo matured oocytes following different sperm treatments: In experiment I, spermatozoa (sperm rich fraction) were capacitated in isolated and ligated uterine horns of estrous gilts (Method A) for at least 3.5 hours and 1x10(6) sperm/ml were exposed to mature oocytes. Of 1586 oocytes 509 (32.1%) developed to the two to eight cell stage. Cleavage stage embryos (n=187) were transferred into nine recipients; 81 embryos (43.3%) were recovered after 72 hours and 21 (26%) had developed to the morula or blastocyst stage. The average number of nuclei (whole mount staining) was 108.4 and indicated normal developmental capacity. Another 127 embryos were transferred into three recipients, two became pregnant and one gilt of them delivered two offspring after 116 days of gestation. In experiment II, two different procedures for the capacitation of spermatozoa using modified TCM 199 medium were compared with that of Method A. Semen was either adjusted to a concentration of 2x10(8) sperm/ml with modified TCM 199E (Method B), or after centrifugation the sperm pellet was diluted in a 1:1 ratio with the same extender (Method C). Motility, and hyperactivity were significantly different (P 0.05) among treatments and were best after uterine incubation (Method A). The percentage of head-to-head aggregation increased significantly (P 0.05) after incubation in the uterine horn, and is suspected to represent a spontaneous acrosome reaction. A total of 492 oocytes were fertilized with semen capacitated by the three methods however, maximal fertilization (34.7%; P 0.05) was obtained with Method B. In experiment III, Method B was repeated and in order to minimize the rate of polyspermy, a total of 298 oocytes were exposed to different sperm concentrations (8x10(3); 4x10(3); 2x10(3) per oocyte). The reduction of spermatozoa exposed to oocytes improved the fertilization rate significantly (P 0.05) from 37.2 to 54.5%.

Differential glycolytic and glycogenogenic transduction pathways in male and female bovine embryos produced in vitro

Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts and that this may be related to differences in glucose metabolism. In addition, an inhibition of phosphatidylinositol 3-kinase (PI3-K) inhibits glucose uptake in murine blastocysts. Therefore, the aim of this study was to identify and compare the expression of proteins involved in glucose metabolism (hexokinase-I, HK-I; phosphofructokinase-1, PFK-1; pyruvate kinase 1/2, PK1/2; glyceraldehyde-3-phosphate dehydrogenase, GAPDH; glucose transporter-1, GLUT-1; and glycogen synthase kinase-3, GSK-3) in male and female bovine blastocysts to determine whether PI3-K has a role in the regulation of the expression of these proteins. Hexokinase-I, PFK-1, PK1/2, GAPDH and GLUT-1 were present in bovine embryos. Protein expression of these proteins and GSK-3 was significantly higher in male compared with female blastocysts. Inhibition of PI3-K with LY294002 significantly decreased the expression of HK-I, PFK-1, GAPDH, GSK-3A/B and GLUT-1. Results showed that the expression of glycolytic proteins HK-I, PFK-1, GAPDH and PK1/2, and the transporters GLUT-1 and GSK-3 is regulated by PI3-K in bovine blastocysts. Moreover, the differential protein expression observed between male and female blastocysts might explain the faster developmental kinetics seen in males, as the expression of main proteins involved in glycolysis and glycogenogenesis was significantly higher in male than female bovine embryos and also could explain the sensitivity of male embryos to a high concentration of glucose, as a positive correlation between GLUT-1 expression and glucose uptake in embryos has been demonstrated.

Toxicity of gold nanoparticles on somatic and reproductive cells

Along with the number of potential applications for gold nanoparticles (AuNP) especially for medical and scientific purposes, the interest in possible toxic effects of such particles is rising. The general perception views nanosized gold colloids as relatively inert towards biological systems. However, a closer analysis of pertinent studies reveals a more complex picture. While the chemical compound of which the nanoparticles consists plays an important role, further biocompatibility determining aspects have been made out. The vast majority of trials concerning AuNP-toxicity were performed using somatic cell culture lines. The results show a considerable dependency of toxic effects on size, zeta potential and surface functionalisation. In vivo studies on this subject are still rare. Based on the existing data it can be assumed, that a dosage of under <400 µg Au/kg showed no untoward effects. If higher amounts were applied toxicity depended on route of administration and particle size. Since nanoparticles have been shown to cross reproduction-relevant biological barriers such as the blood-testicle and the placental barrier the question of their reprotoxicity arises. Yet data concerning this subject is far from adequate. Regarding gametes, recent experiments showed a dose-dependent sensitivity of spermatozoa towards AuNP. Oocytes have not yet been tested in that respect. Interestingly, so far no effects were detected on embryos after gold nanoparticle exposure. In conclusion, the biocompatibility of gold nanoparticles depends on a range of particle specific aspects as well as the choice of target tissue. Further clarification of such matters are subject to ongoing research.

328 ANALYSIS OF FLUOROPHORE-EXPRESSING SPERMATOZOA FROM TRANSGENIC BOARS PRODUCED BY SLEEPING BEAUTY TRANSPOSITION

The pig is an important model for biomedical research. Recently, we described a method for producing transgenic pigs using a nonautonomous Sleeping Beauty (SB) transposon1 (Garrels et al. 2010 Reprod. Domest. Anim. 45, 65 abst.). Briefly, in vivo developed porcine zygotes were co-injected with a CAGGS-Venus transposon and hyperactive SB100. A total of 141 in vivo developed zygotes were injected and transferred to synchronized foster sows. Subsequent analysis revealed specific transposase-mediated integration of 1 to 5 copies of the Venus transposon in fetuses and piglets. This method results in highly efficient SB-mediated transgene transposition into the porcine genome: 57% of the fetuses examined and 42% of piglets were transgenic, representing 6.4% of the treated zygotes. The piglets showed persistent expression of the Venus reporter. Here, we present cellular analysis of 2 founder boars. Expression of the Venus reporter was observed in skin, cultured fibroblasts, leukocytes, and spermatozoa of both animals. However, flow cytometric measurement of leukocytes and cultured ear fibroblasts revealed that these boars carried both a Venus-fluorescence-positive population and a Venus-fluorescence-negative cell population. PCR analysis revealed that the Venus-fluorescence-negative cells were genotypically negative, indicating transgene mosaicism. Interestingly, all spermatozoa tested were Venus-positive and gave a distinct fluorescence peak in repeated flow-cytometric measurements (n = 6). Fluorescence microscopy revealed localisation of the Venus fluorophore in the sperm tail, in the midpiece, and in the equatorial segment of the sperm head. Motility of the transgenic sperm as measured by computer-assisted sperm analysis (Hamilton-Thorne, Beverly, MA, USA) indicated no decrease in percentage of motile sperm and the movement patterns. Sorting Hoechst 33342–stained transgenic sperm into X- and Y-chromosome bearing populations did not reveal any differences in Venus fluorescence between these 2 groups. To test the fertility of the transgenic sperm, 6 wild-type sows were artificially inseminated. Four pregnancies were established, 2 of these sows were sacrificed on Day 29 of gestation and a total of 9 Venus-positive normally developed fetuses and 2 degenerated fetuses were recovered. The other 2 pregnancies are ongoing at the time of writing. This is the first characterisation of spermatozoa from transposon transgenic pigs. The results show that Venus transposon–bearing transgenic spermatozoa are fertile and demonstrate germline transmission to the F1 offspring. Sleeping Beauty-mediated transposition is thus a promising approach for genetic modification of the pig genome.

103 TRANSDUCTION PATHWAYS RELATED TO GLUCOSE METABOLISM IN MALE AND FEMALE BOVINE EMBRYOS PRODUCED IN VITRO

Glucose metabolism plays an important role in energy balance control in mammalian cells and has been widely used as an indicator of embryo developmental competence. Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts, which may be related to differences in glucose consumption and metabolism. In addition, we have demonstrated that inhibition of phosphatidylinositol 3-kinase (PI3-K) with a structurally unrelated inhibitor, LY294002, suggests a negative role for PI3-K in the regulation of bovine embryo development (Aparicio et al. 2010 Reproduction 140, 83–92). The aim of this study was to determine whether PI3-K has a role in the regulation of glucose metabolism in Day 7 bovine blastocysts and to study the possible differential protein expression involved in glucose metabolism [hexokinase-I (HK-I), phosphofructokinase-1 (PFK-1), pyruvate kinase1/2 (PMK1/2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A/C (LDHA/C), glucose transporter-1 (GLUT-1) and glycogen synthase kinase-3 (GSK-3A/B)] between in vitro produced male and female embryos derived from IVF with either X- or Y-sorted semen. Day 7 blastocysts derived from unsorted semen (n = 25 blastocysts per group) were incubated up to 12 h in SOF culture medium in the presence or absence of LY294002 (10 μM) and stored. Similarly, male and female Day 7 blastocysts derived from sorted semen were collected apart and stored at –80°C until proteomic analysis (Western blot analysis of proteins separated by sodium dodecyl sulfate-polyacylamide gel electrophoresis). Inhibition of PI3K significantly decreased HK-I (P < 0.01), PFK-1 (P < 0.001), GAPDH (P < 0.05), GSK-3A/B (P < 0.001), and GLUT-1 (P < 0.01) protein levels. Interestingly, protein expression of HK-1 (P < 0.001), PFK-1 (P < 0.01), PMK1/2 (P < 0.05), GAPDH (P < 0.01), and GLUT-1 (P < 0.001) was significantly higher in male compared with female blastocysts. The significant increase in the phosphorylated forms (Ser21 and Ser9) of both isoforms (GSK-3A/B) in male compared with female embryos is indicative of a higher inactivation of GSK-3A/B in males (P < 0.001). The presence of LDHA/C activity was not detected in any blastocyst group, irrespective of the gender or treatment studied. In conclusion, our data suggest that PI3K plays a major role in the regulation of glucose metabolism in bovine embryos, because pretreatment with LY294002 significantly modified the protein expression of HK-I, PFK-1, GAPDH, GSK- 3A/B, and GLUT-1, and underline the possibility of modulating glucose metabolism via the PI3K cellular pathway. The differential glycolytic metabolism between male and female blastocysts might explain the higher developmental kinetic rates in males described by other authors, because the expression of proteins involved in glycolysis and glycogenogenesis was significantly higher in male than in female in vitro-produced bovine embryos.

164 DEVELOPMENT OF MURINE EMBRYOS AFTER INJECTION OF UNCOATED GOLD AND SILVER NANOPARTICLES

Novel techniques such as ultrashort pulsed laser technology to produce in situ bio-conjugated nanoparticles (NP) as biomarkers for optical imaging and intervention hold great potential to observe dynamic processes in gametes and embryos without affecting their developmental potential. With regard to toxicology, current preliminary evidence is mainly based on specific cell lines and suggests low toxicity for gold NP (GNP), but a higher toxicity for silver NP (SNP), which also possess a considerable antibacterial effect. Little is known about their impact on sensitive biological systems as early mammalian embryos. The present study investigated the potential toxicity of GNP and SNP in murine embryos for the first time. Since the NP were laser-generated, they formed a stable dispersion in water without the need of surface coating, which might have caused additional toxic effects. Approximately 10 pL of a NP díspersion (average NP diameter of 15 nm) containing 50 μg mL-1 of either GNP or SNP were injected into 1 blastomere of 2-cell-stage embryos (n = 93 or 75, respectively), derived from superovulated NMRI mice. Embryos injected with water alone (n = 79) served as controls. Untreated embryos (n = 92) were run as a handling control. Successful NP injection was confirmed using laser scanning confocal microscopy. After treatment, embryos were cultured for 72 h at 37°C and 5% CO2 in KSOM plus 1% BSA. Embryo development was assessed on a daily basis. No abnormal development was observed. The handling controls reached a blastocyst rate of 77.2%. A total of 66.2% of the water-injected embryos developed to blastocysts, compared to 62.4% and 56.0% after injection of GNP and SNP, respectively. Neither 1-way ANOVA nor an additional chi-square test indicated significant differences between treatment groups. In conclusion, these preliminary data indicate that intracytoplasmatic injection of GNP and SNP had no significant impact on embryo development. Further tests, including qRT-PCR of development-relevant genes in blastocysts and transfer of injected embryos into recipient animals to study potential long-term effects, are underway to gain a better understanding of GNP and SNP embryo toxicology. We gratefully acknowledge the support of the Masterrind GmbH Verden and the NBank Niedersachsen.

Incidence of chromosomal abnormalities in bovine blastocysts derived from unsorted and sex-sorted spermatozoa

The aim of the present study was to examine the incidence of chromosomal abnormalities in bovine blastocysts produced by IVF with unsorted, X-sorted or Y-sorted spermatozoa. In Experiment 1, individual blastocysts were processed to examine the incidence of mixoploidy using fluorescent in situ hybridisation. Overall, 80% (44/55) of blastocysts were mixoploid (10/15, 14/15 and 20/25 for X-sorted, Y-sorted and unsorted spermatozoa, respectively; P > 0.05). However, the prevalence of abnormal XY chromosome complements was relatively low in all groups; on average, only a small fraction of the total nuclei per embryo appeared polyploid (1.64%, 5.62% and 6.0% for X-sorted, Y-sorted and unsorted spermatozoa, respectively). Interestingly, 20% (5/25) of blastocysts derived from unsorted spermatozoa were found to be chimeric (XX/XY). In Experiment 2, chimeric embryos were detected among the blastocysts derived from two of five sires tested. In addition, one chimeric blastocyst was detected among nine in vivo-derived blastocysts obtained following AI. In conclusion, based on the results of the present study, the incidence of chromosomal abnormalities did not different between blastocysts derived from sex-sorted or unsorted spermatozoa. In addition, the occurrence of mixed sex chimeras was not limited to a single sire and was not unique to blastocysts derived from IVF.

Macrocephaly in bull spermatozoa is associated with nuclear vacuoles, diploidy and alteration of chromatin condensation

Spermatozoa from 2 dairy AI (artificial insemination) bulls (A and B), identified by their abnormal spermiogram with cells depicting frequent macrocephaly, double tails and nuclear vacuoles, were case-investigated and compared to normal spermatozoa from a control AI sire (C). Head sizes were measured and morphological abnormalities scored using brightfield and differential interference contrast microscopy. The degree of sperm maturation and of resistance to acid-induced DNA denaturation in situ were determined after uploading of acridine orange using flow cytometry of 5,000 cells/sample. Nuclear fragmentation, i.e. the ratio of red to total (red + green) fluorescence, reached 7.1% and 31% in bulls A and B, compared to 2% in bull C. The proportion of immature spermatozoa, i.e. those with incomplete histone-protamine exchange and depicting higher green fluorescence compared to the main population of the control bull, reached 9.54% in A and 7.75% in B, compared to only 0.47% in the control. In the second part of this study the previously unknown chromosomal constitution of large-headed spermatozoa of bull A was investigated by fluorescence in situ hybridization using an X-Y painting probe set. The 7.5% XY-bearing cells and the presence of diploid spermatozoa detected by flow cytometry indicate a meiotic arrest in the first division in bull A, becoming the first proven case of association of macrocephaly and M1 diploidy. The diverse approaches used for the investigation of spermatozoal DNA provide insights into the etiology of macrocephaly.

Diploid spermatozoa caused by failure of the second meiotic division in a bull

An artificial insemination bull (Bos taurus) exhibiting 23% macrocephalic spermatozoa in the ejaculate was investigated. Spermatozoa with a projected head area of > or = 52 microm(2) were considered macrocephalic. Diploidy was assumed from the measurement of sperm head area and proved by flow cytometry, which was used to sort the sperm into haploid and diploid fractions. Fluorescence in situ hybridization was used to detect the sex chromosomes with an X-Y probe set. Diploid spermatozoa most likely originate from a defective second meiotic division (M2 diploids), as only 0.7% XY-bearing spermatozoa (M1 diploids) were detected in the spermatozoa of the flow cytometric diploid sort. The painting probes generated a single X or Y spot for both unsorted semen and diploid sorted spermatozoa. This indicates a close proximity of the nonpartitioned sister chromatids in the spermatozoa. The BC1.2 probe, which labels BTAYp13-12, was used to clarify the presence of the two chromatids in the singular signal of the simultaneously hybridized Y-painting probe. In scoring more than 1000 randomly sampled spermatozoa hybridized with the BC1.2 probe, 32% showed the YY diploid signal and 18% the Y signal. The sperm diploidy in this bull was caused by an incomplete partitioning of sister chromatids during the second meiotic division (M2) associated with a failure in nuclear cleavage.

Elevated histone H1 (MPF) and mitogen-activated protein kinase activities in pig oocytes following in vitro maturation do not indicate cytoplasmic maturation

Effects of different media (TCM 199 + BSA, TCM 199 + FCS, TCM 199 + NBCS, Whitten's medium + BSA) supplemented with estradiol-17beta and two isolated and everted follicle shells on MPF and MAP kinase activities and the sensitivity to parthenogenetic activation of pig oocytes were examined at the end of culture (48 h). Elevated (P < 0.05) activities of MAP kinase were recorded in metaphase II oocytes following culture in Whitten's medium, whereas MPF levels were lowest (P < 0.05) in MII oocytes matured in TCM 199 supplemented with BSA. Oocytes matured in TCM 199 based media showed higher (P < 0.05) activation rates when compared to oocytes incubated in Whitten's medium. Whitten's medium supplemented with different protein sources (amino acids, FCS, BSA) was used to study the effects of different exposure periods to eCG/hCG stimulation on MPF and MAP kinase activities and in vivo fertilisability following culture for 48 h. MPF and MAP kinase activities were significantly increased by eCG/hCG stimulation of COCs during maturation. Further, the continuous presence of eCG/hCG during culture (48 h) significantly increased the levels of both kinases in comparison to stimulation by gonadotrophins alone during the first 24 h of incubation. In vivo fertilisation of oocytes matured in Whitten's medium supplemented with eCG/hCG for 24 or 48 h led to a significant retardation of early embryonic development compared to ovulated oocytes. In conclusion, media composition and gonadotrophin stimulation affect MPF/MAP kinase activities and the susceptibility to parthenogenetic activation of IVM oocytes. However, elevated kinase levels in pig oocytes following culture do not indicate complete cytoplasmic maturation.

Recent advances in boar semen cryopreservation

Since 35 years ago boar semen has been frozen and used for artificial insemination (AI). However, fertility of cryopreserved porcine sperm has consistently been low as boar sperm are more sensitive to cellular stress imposed by changing osmotic balance, oxidative stress, low-temperature exposure, cryo-protectant intoxication etc. and are less able to compensate for these deficiencies at commercially applicable dosages. Additionally, differences in sperm freezability among individuals are well known. Here we review current advances on tests to screen sperm quality post-thaw, on ways of diminishing individual boar effects, on improvement of cryo-protection by novel extender components, on packaging and freezing protocols and freezing and thawing methods, and on the handling of sexed boar sperm. Major advances have been registered, which have improved cryo-survival and the capacity to process boar semen for commercial AI.

Improved quality of sex-sorted sperm: a prerequisite for wider commercial application

To date the only successful method to sort sperm into X- and Y-chromosome-bearing populations is the Beltsville Sperm Sexing Technology. Fertility results continue to be variable even though the technology has been used in a commercial setting for nearly a decade. This is at least partly due to the reduced lifespan of sperm after sorting and freezing. Several technical and biological factors are responsible for this problem. Furthermore, to meet economic demands, only 10-15% of the number of sperm (compared to unsexed semen) are loaded in each straw, further limiting the chances for fertilization. A new protocol for preservation of bull sperm, utilizing Sexcess shows promise in extending the lifespan of sorted bull sperm. Motility and acrosome integrity are significantly increased using Sexcess. Conception rates achieved with heifers for those bulls tested with Sexcess and using a standard AI regime give results that do not differ from results achieved using regular AI. In addition to the improvements of the sorting technology itself, we recommend a thorough pre-selection of bulls. A reliable prediction method to determine whether a bull is suitable for a sex-sorting program still does not exist. Such a test is needed, especially for "custom sorting" programs. Currently, test sorts are the only means of obtaining information about the sorting efficiency of semen from a particular bull.