Protective effects of the cumulus-corona radiata complex during vitrification of horse oocytes

Vitrifying oocytes is a potentially valuable means of preserving the female germ line, but significantly compromises oocyte developmental competence. This study examined the hypothesis that the cumulus complex protects the oocyte during vitrification. Vitrified-warmed immature cumulus oocyte complexes (COCs) were labelled with a plasma membrane impermeant DNA marker (ethidium homodimer-1) to examine the percentage and location of dead cumulus cells, and to investigate the effect of the proportion of dead cells (+1,+2 or +3) on the success of in vitro maturation (IVM). Further, oocytes were labelled for connexin-43 or injected with Lucifer yellow dye to determine whether the integrity of the gap junctions between an oocyte and its cumulus was compromised by vitrification. Finally, the effect of denuding immature and mature oocytes on their ability to withstand vitrification was examined. Cryopreserving immature COCs increased the number of dead cumulus cells (13 vs 2.6% for controls; P<0.05). However, an increased proportion of dead cumulus cells did not affect post-warming maturation rates (∼30% MII) presumably because dead cells were located at the periphery of the cumulus mass and cumulus-oocyte gap junction communication was not disrupted. Moreover, cumulus removal prior to IVM or vitrification indicated that while the cumulus does protect immature oocytes during vitrification it does so by mechanisms other than support during maturation. Cumulus presence was also found to protect mature equine oocytes against vitrification-induced damage since cumulus-enclosed MII oocytes preserved their meiotic spindle quality better during vitrification than denuded oocytes (38.1 vs 3.1% normal spindles; P<0.05).

262 ICSI OF EQUINE OOCYTES WITH SEX-SORTED FROZEN-THAWED SEMEN RESULTS IN LOW CLEAVAGE RATE BUT NORMAL EMBRYO DEVELOPMENT AND PREGNANCIES

Sorting of sperm by flow cytometer has allowed selection of offspring of predetermined sex in several species by artificial insemination, although the success rate is often lower than with non-sexed semen. In horses, the problem was partially overcome with hysteroscopic insemination using sex-sorted fresh sperm. However, when sex-sorted frozen–thawed sperm were used the pregnancy rate was heavily reduced in comparison with non-sexed frozen–thawed semen. Because it has been demonstrated that in vitro assisted reproductive techniques, namely intracytoplasmic sperm injection (ICSI), has permitted live foals to be obtained using sperm with low fertility in the field, in this study we investigated the possibility of using ICSI with sexed-sorted frozen–thawed sperm for equine embryo production in vitro. Briefly, semen was collected from two Standardbred stallions of proven fertility (Stallions A, B), sorted using a MoFlo SX flow cytometer and frozen (Johnson LA and Welch GR 1999 Theriogenology 52, 1323–1341). Sex-sorted and control non-sexed frozen semen (two stallions of in vitro proven fertility: C, D) was thawed, centrifuged on a Percoll gradient, washed and diluted 1:1 in PVP before ICSI. Oocytes were collected from ovaries of slaughtered mares and matured in vitro. Metaphase II oocytes were injected with sperm, subsequently cultured up to the blastocyst stage and frozen conventionally in 10% of glycerol (Galli et al. 2002 Theriogenology 58, 713–715). Six embryos from sexed-sorted sperm were thawed and non-surgically transferred in naturally cycling synchronous recipient mares. Results are summarized in Table 1. Overall, 70 and 58 (stallion A, B) and 30 and 15 (stallion C, D) oocytes were injected with sex-sorted or control frozen–thawed sperm, respectively. Mean cleavage rates were 20.3% for sorted sexed sperm and 71.1% for control, showing a significantly lower cleavage rate for sexed sperm. This difference was reflected in the number of blastocysts obtained (4.7% v. 20.0%). From the 6 frozen–thawed embryos derived from sexed sperm, that were transferred, 4 pregnancies resulted. One pregnancy was lost around 21 days, a second was pharmacologically aborted, and two were maintained (one from male and one from female sorted semen are currently in the 11th month of gestation). In conclusion, this study demonstrates that ICSI with sex-sorted sperm can be used for producing equine blastocysts able to establish pregnancies at a high rate following embryo transfer. However, the overall efficiency of the system is limited due to the very low cleavage rate obtained with sexed-sorted frozen–thawed sperm. Table 1.Development of embryos produced by ICSI with sorted and non-sorted frozen–thawed semen This work was supported by an RFO (ex 60%) and Camera di Commercio Cremona grant. The Authors wish to thank Società Italiana Produttori Sementi.

The in vitro effects of cigarette smoke on fatty acid metabolism are partially counteracted by simvastatin

BACKGROUND

Statins enhance the synthesis of long-chain polyunsaturated fatty acids (LC-PUFAs) from their precursors both in vitro and in vivo. In particular, an increased conversion of linoleic acid (LA) and of alpha-linolenic acid to their derivatives is observed in cultured cells. On the contrary, cigarette smoke (CS) negatively and dose-dependently affects the LC-PUFA production.

AIM

To evaluate the effects of CS alone or with simvastatin, on [1-(14)C] LA metabolism in THP-1 cells.

RESULTS

CS inhibits LA conversion; after co-incubation, simvastatin nullifies the effects of CS, maintaining LA conversion comparable to controls. However, at the highest CS concentration, simvastatin is unable to counteract the effects of CS. Changes of LA conversion reflect the modulation of desaturase activities by simvastatin and CS.

CONCLUSION

CS decreases PUFA conversion and its effects are modulated by the opposite effect of statins. It can be speculated that statin treatments in smoking patients may provide some beneficial effects on PUFA metabolism in addition to lowering cholesterol levels.

BioEnterics intragastric balloon for treatment of morbid obesity in Prader-Willi syndrome: specific risks and benefits

BACKGROUND

Obesity in Prader-Willi Syndrome (PWS) is progressive, severe, and resistant to dietary, pharmacological, and behavioral treatment. A body weight reduction is mandatory to reduce the risk of cardio-respiratory and metabolic complications. The aim of the study was to assess risks and benefits of BioEnterics Intragastric Balloon (BIB) for treatment of morbid obesity in PWS patients.

METHODS

Twenty-one BIB were positioned in 12 PWS patients (4 M, 8 F), aged from 8.1 to 30.1 years, and removed after 8 +/- 1.4 months (range: 5-10 months). Auxological, clinical, and nutritional evaluations were performed every 2 months. Variations in body composition were analysed by dual energy X-ray absorbiometry (DXA).

RESULTS

One patient (28.5 years, BMI: 59.3 kg/m(2)) died 22 days after BIB positioning because of gastric perforation. In another case (26.2 years, BMI: 57.6 kg/m(2)), BIB was surgically removed after 25 days because of symptoms suggesting gastric perforation (not confirmed). The remaining ten patients showed a significant decrease of BMI (p = 0.005) and of fat tissue as measured by DXA (p = 0.012). No significant modifications in bone mineral density (BMD) occurred, but a slight loss in lean body mass (p = 0.036) was documented. In five patients, BIB treatment was repeated more than once.

CONCLUSION

This study shows that when noninvasive pharmacological therapies fail, BIB may be effective to control body weight in PWS patients with morbid obesity, particularly when treatment is started in early childhood. However, careful clinical follow-up and close collaboration with parents are crucial to avoid severe complications, which can be caused by persisting unrestrained food intake.

Maternal smoking habits are associated with differences in infants' long-chain polyunsaturated fatty acids in whole blood: a case-control study

OBJECTIVE

To study the effects of maternal smoking on the status of long-chain polyunsaturated fatty acids (LCPUFA) in infants' whole-blood lipids.

DESIGN

A case-control matched study planned on the basis of preliminary observations.

SETTING

Maternity ward.

PATIENTS

A total of 159 healthy, term, breastfed infants with weight appropriate for gestational age, subdivided (53 per group) into those born to non-smokers (reference), smokers (> or = 5 cigarettes per day) who either stopped within the first trimester of pregnancy (early smokers) or who continued througout pregnancy (late smokers).

INTERVENTIONS

The fatty acid profile of 4-day-old infants was determined on whole blood.

RESULTS

Higher levels of linoleic (LA) and alpha-linolenic acid (ALA) and lower levels of the metabolic products di-homo-gammalinolenic (DHGLA) and arachidonic (AA), of the n-6 series, and docosahexaenoic acid (DHA), of the n-3 series, were found in infants born to late smokers compared with the reference group. The DHGLA/LA and AA/DHGLA ratios in the n-6 series and DHA/ALA in the n-3 series, which are indices of the metabolic processes in LCPUFA synthesis, were lower in infants born to smokers compared with those born to non-smokers. Infants born to early smokers showed n-6 PUFA levels and ratios similar to references and n-3 parameters closer to those born to late smokers. No dietary differences were found among the three groups of mothers. All the independent associations with smoking persisted after adjustment for maternal covariates. Pre-pregnancy body weight, which is lower in late smokers compared with non-smokers, independently correlated with LCPUFA levels in both series.

CONCLUSIONS

Maternal smoking is associated with a reduction in LCPUFA pools in infants, which might have structural and functional consequences.

Analysis of living cells grown on different titanium surfaces by time-lapse confocal microscopy

In this study we have combined fluorescence- and reflection-confocal laser scanning microscopy for the simultaneous visualization of living cells and surface topography beneath them. To this purpose we have designed a specific flow chamber and we have tested it with osteoblasts grown on an opaque, thick support, made of smooth or sandblasted titanium. Cells were loaded with Calcein-AM or tetramethylrhodamine methyl ester (TMRM), two probes employed as indicators of cell viability/morphology and mitochondrial membrane potential, respectively. Besides the acquisition of stacks of confocal sections, the system allowed also vertical views and faithful three-dimensional reconstruction of the samples. Confocal microscope implemented with our flow chamber proved to be a promising tool for time-lapse investigation of cell-biomaterial interactions.

300 HEMIZYGOUS PRION PROTEIN GENE (PRNP) KNOCKOUT IN CATTLE FIBROBLASTS

Bovine spongiform encephalopathy (BSE) represents a real threat for human health, as has been demonstrated by the causal link with the variant form of Creutzfeldt-Jakob disease. The aim of our project is to create a bovine strain knockout for the prion protein gene (PRNP) that should be resistant to BSE infection. We combined the use of homologous recombination by PRNP targeting vectors in bovine fibroblasts with the subsequent use of nuclear transfer (NT). We transfected fetal (male) and adult (female) bovine fibroblasts by nucleofection, using targeting vectors disrupting the PRNP by means of loxP flanked cassettes. They expressed resistance to different drugs driven by a PGK or TK promoter and the thymidine kinase gene as a negative selection marker. We screened, by PCR, 907 drug-resistant colonies, from which we identified 8 Neo-resistant colonies with a recombined PRNP allele (overall efficiency 3.2%; 7/108 from fetal, 1/145 from adult; P < 0.5). Fibroblasts PRNP+/– Neo were used to produce NT blastocysts from which neural precursors cell lines were established (Lazzari et al. 2006 Stem Cells 24, 2514–2521). These lines were capable of extensive proliferation (over 120 doublings during 4 months of culture) and provided unlimited material for Southern blot analysis to confirm PCR findings. Three clones (2 from fetal and 1 from adult) were further analyzed and confirmed PRNP+/– by Southern blot and were subsequently used for NT to generate blastocysts for transfer to recipient heifers. On Day +40 of gestation, the pregnancy rate was 33.3% (9/30) for the fetal line and 50% (2/4) for the adult line. One of the fetuses originating from fetal fibroblasts was removed on Day +45 to establish a rejuvenated fibroblast cell line used for a second round of gene targeting to obtain a PRNP –/– clone. We nucleofected these fibroblasts with Puro, Hygro, and promoterless Hygro cassette-carrying targeting vectors. We screened 625 drug-resistant colonies by PCR but none tested positive for the second targeting. In conclusion, we have obtained heterozygous PRNP+/– fibroblasts with the Neo vector both in fetal and adult fibroblasts, but failed with other vectors. In the first targeting, the efficiency was 10 times greater in fetal v. adult fibroblasts. The derivation of neural precursor cell lines from cloned blastocysts is a useful procedure to have sufficient material for molecular analysis without the need of rejuvenating the cell through the production of a fetus. None of the vectors used for the targeting of the second allele was successful.

170 EXPRESSION PATTERN OF THE Sox2 GENE IN BOVINE OOCYTES AND IN VITRO-DERIVED EMBRYOS

Sox2 is a member of the Sox (SRY-related HMGbox) family. It acts to maintain developmental potential and marks the pluripotent lineage of the early mouse embryo; in particular, as in the case of Oct-4 and Nanog, Sox2 is expressed specifically in the inner cell mass (ICM) and in the epiblast of this species. Moreover, it plays an important role in the transcription network that maintains stem cell pluripotency, interacting with other factors such as Oct-4 and Nanog. Little information is available on this gene in bovine; therefore aims of the present study were: a) to identify and characterize the Sox2 expression profile in bovine oocytes and preimplantation embryos; and b) to investigate its expression pattern in ICM and trophectoderm (TE). Bovine oocytes and embryos were obtained by in vitro maturation and fertilization; blastocysts at Day 7 post-insemination underwent microsurgery to separate TE from ICM. mRNA was isolated from 3 pools, each consisting of 5 MII oocytes, 2-, 4-, 8-, and 16-cell embryos, morulae, blastocysts, ICMs, and TEs. Semi-quantitative analysis of Sox2 expression was performed in the exponential phase of PCR amplification using rabbit globin as exogenous control. Data were analyzed with one-way ANOVA, followed by multiple pairwise comparisons with Tukey test (SigmaStat 2.03, SPSS, Inc., Chicago, IL, USA). Values are presented as mean � SEM and differences of P ≤ 0.05 are considered significant. In order to rule out false negative results, PCR amplifications of isolated ICMs and TEs were extended to the plateau phase. Fragment identity was confirmed by sequencing. Comparison of bovine Sox2 cDNA sequence (EMBL AM774325) with databases revealed a 98%, 93%, and 87% homology with sheep, human, and mouse, respectively. Sox2 mRNA was detectable in oocytes as well as in embryos at the different developmental stages analyzed. Semi-quantitative expression studies revealed that Sox2 was present as both maternal and embryonic transcript; in particular, a statistically significant increase from the 8-cell stage, concomitant with embryo genome activation, was observed. Differently from the mouse, Sox2 was expressed in both bovine ICM and TE, resembling the profile previously shown for Oct-4 (van Eijk et al. 1999 Biol. Reprod. 60, 1093–1103), and suggesting that Sox2 expression might be regulated by Oct-4 also in bovine, as described in mouse and human. These findings also suggest that its expression may become restricted to the ICM only at the expanded hatched stage, as previously described for Oct-4 in pig embryos (Vejlsted et al. 2006 Mol. Reprod. Dev. 73, 709–718). This work was supported by PRIN 2006, FIRST 2005, TECLA-MIUR, and EUROSTELLS-ESF.

308 INFLUENCE OFA MATRIX ATTACHMENT REGION ON THE EXPRESSION OF BICISTRONIC VECTORS TRANSFECTED IN MAMMALIAN CELLS CULTURED IN VITRO

We investigated the effect of the 52 MAR (matrix attachment region) sequence of chicken lysozyme gene as a possible insulator for the expression of our transgenes in somatic cells to be used for nuclear transfer. With the preliminary purpose to demonstrate a possible positive effect (position or copy number) on the long-term combined expression during in vitro culture, we have created a bicistronic ubiquitous expression vector with (MAR+) or without (MAR–) MAR. The main structure of our constructs is composed of the pCAGGS promoter driving the expression of a reporter gene (enhanced green fluorescent protein, EGFP) followed by a loxable selection cassette (loxP-PGKneo). The MAR region was inserted before the selection cassette. After KpnI digestion, the resulting linearized vectors were purified and subsequently used to transfect adult porcine fibroblast cell lines using the Nucleofector system (Amaxa, Cologne, Germany). Fibroblasts were cultured in DMEM/M199 medium (1:1) + 10% FCS supplemented with 5 ng mL–1 of basic fibroblast growth factor (bFGF). In every experiment, 1 � 106 cells were transfected with 2.5 µg of linearized plasmid and selected for 3 weeks with medium supplemented with 400 µg mL–1 of Geneticin (G418 sulfate, Calbiochem, La Jolla, CA). On Day 8 of G418 selection, we analyzed 150 colonies for each treatment, using fluorescence microscopy with fluorescein isothiocyanate filters. Colonies were classified according to size (large) and cell morphology (small cells without signs of aging). In addition, colonies were classified for uniform GFP expression (uniform), patchy GFP expression (variegated), and no GFP expression (negative). Resistant colonies derived from MAR+ and MAR– vectors, respectively, had 36 (24%), 42 (28%), and 56 (37%) v. 79 (53%), 58 (39%), and 29 (19%) uniform, variegated, and negative GFP. Differences were significant for variegated and negative in MAR+ v. MAR– (chi square, P < 0.05). Thirty-six MAR+ and 42 MAR– colonies uniformly expressing GFP were transferred to 24-well plates and subjected to G418 selection until Day 22, when 7 MAR+ and 15 MAR– clones were still growing in culture. Four of seven MAR+ (57%) and 7/15 MAR– (47%) uniformly expressed high levels of GFP. In conclusion, we found that significantly fewer colonies expressed GFP with the MAR+ vector; however, within the GFP-expressing clones, expression was more uniform. Therefore, we did not find a beneficial effect of MAR sequences on expression in somatic cells during in vitro culture; however, further work is needed to investigate their effect after nuclear transfer and/or on the next generation of cloned transgenic animals.

Phase II study of sequential chemotherapy with docetaxel-estramustine followed by mitoxantrone-prednisone in patients with advanced hormone-refractory prostate cancer

Sequential chemotherapy may improve treatment efficacy avoiding the additive toxicity associated with concomitant polichemotherapy in hormone-refractory prostate cancer (HRPC). Forty patients received docetaxel 30 mg m⁻² intravenous (i.v.), weekly, plus estramustine 280 mg twice daily for 12 weeks. After 2 weeks rest, patients with a decline or stable PSA were treated with mitoxantrone 12 mg m⁻² i.v. every 3 weeks plus prednisone 5 mg twice daily for 12 cycles. Forty patients were assessable for toxicity after docetaxel/estramustine. Main toxicities were grade 3–4 AST/ALT or bilirubin increase in seven patients (17.5%) and deep venous thrombosis (DVT) in four patients (10%). Twenty-seven patients received mitoxantrone/prednisone. Main toxicities included DVT in one patient (3.7%) and congestive heart failure in two patients (7%). Thirty-nine patients were assessable for PSA response. Twenty-nine patients (72.5%; 95% CI 63–82%) obtained a ⩾50% PSA decline with 15 patients (37.5%; 95% CI 20–50%) that demonstrated a ⩾90% decrease. Median progression-free and overall survival were respectively 7.0 (95% CI 5.8–8.2 months) and 19.2 months (95% CI 13.9–24.3 months). In conclusion, although this regimen demonstrated a favourable toxicity profile, sequential administration of mitoxantrone is not able to improve docetaxel activity in patients with HRPC.

Fatty acid composition of plasma, blood cells and whole blood: relevance for the assessment of the fatty acid status in humans

The composition and incorporation of fatty acids (FA) in plasma and blood cells is the result of distinct processes: intake, metabolism and peripheral utilization.

AIM OF THE STUDY

was to compare the FA profile in plasma, lipoproteins and blood cells with that in whole blood (WB) from healthy volunteers; to assess the quantitative distribution of selected FA in triacylglycerols, cholesteryl esters and phospholipids. Lipid FA profiles are comparable in plasma and lipoproteins but differ from those in blood cells. In WB, the FA profile results from the balanced proportion of FA pools in plasma and cells. The contribution of each lipid class to the total amount of FA differs among blood specimens. Phospholipids of plasma and red blood cell are the major contributors to the FA amount and profile in WB. In conclusion, the FA profile of WB reflects the FA status and WB could be an adequate specimen for the assessment of FA intakes.

Temozolomide and thalidomide in the treatment of glioblastoma multiforme

OBJECTIVE

The aim of this study was to assess efficacy and toxicity of temozolomide given alone or in combination with thalidomide, an anti-angiogenetic drug, in patients with newly diagnosed glioblastoma multiforme (GBM).

PATIENTS AND METHODS

46 patients with histologically proven GBM were eligible for inclusion. Twenty-three patients (15 males and 8 females) received temozolomide on a conventional schedule; 23 patients (12 males and 11 females) received temozolomide on the same schedule and thalidomide was dose-adjusted in each individual patient based on their tolerance.

RESULTS

The median survival time was 12 months for temozolomide and 13 months for temozolomide + thalidomide.

CONCLUSION

The administration of temozolomide in association with thalidomide after radiotherapy (RT) does not offer an advantage over temozolomide alone in adults with newly diagnosed GBM. The two therapeutic strategies produce similar results for survival, but the latter regimen shows a moderate increase in toxicity.

The fatty acid profiles in a drop of blood from a fingertip correlate with physiological, dietary and lifestyle parameters in volunteers

Limited data are available on the fatty acid (FA) composition of circulating lipids and the associations with diet, physiological and pathological conditions, due to the complexity and costs of the analytical process. The aim of our study was to evaluate the FA composition in 108 healthy subjects and to correlate the data with gender, pregnancy, dietary habits, lifestyle, and short-term controlled intake of n-3 FA, using an innovative analytical approach for the collection and processing of blood samples. Ten subjects were also supplemented with n-3 polyunsaturated FA as smoked salmon or capsules for 3 weeks. The resulting blood FA composition was affected by gender, pregnancy, diet and smoking. The data indicate that this new analytical methodology is suitable for assessing associations between circulating FA and various parameters in large population groups, and is applicable to epidemiological studies and in the assessment of the effects of controlled FA supplementation in clinical studies.

Surgical treatment of drug-resistant nocturnal frontal lobe epilepsy

Of the cases with nocturnal frontal lobe epilepsy (NFLE) approximately 30% are refractory to antiepileptic medication, with several patients suffering from the effects of both ongoing seizures and disrupted sleep. From a consecutive series of 522 patients operated on for drug-resistant focal epilepsy, 21 cases (4%), whose frontal lobe seizures occurred almost exclusively (>90%) during sleep, were selected. All patients underwent a comprehensive pre-surgical evaluation, which included history, interictal EEG, scalp video-EEG monitoring, high-resolution MRI and, when indicated, invasive recording by stereo-EEG (SEEG). There were 11 males and 10 females, whose mean age at seizure onset was 6.2 years, mean age at surgery was 24.7 years and seizure frequency ranged from <20/month to >300/month. Nine patients reported excessive daytime sleepiness (EDS). Prevalent ictal clinical signs were represented by asymmetric posturing (6 cases), hyperkinetic automatisms (10 cases), combined tonic posturing and hyperkinetic automatisms (4 cases) and mimetic automatisms (1 case). All patients reported some kind of subjective manifestations. Interictal and ictal EEG provided lateralizing or localizing information in most patients. MRI was unrevealing in 10 cases and it showed a focal anatomical abnormality in one frontal lobe in 11 cases. Eighteen patients underwent a SEEG evaluation to better define the epileptogenic zone (EZ). All patients received a microsurgical resection in one frontal lobe, tailored according to pre-surgical evaluations. Two patients were operated on twice owing to poor results after the first resection. Histology demonstrated a Taylor-type focal cortical dysplasia (FCD) in 16 patients and an architectural FCD in 4. In one case no histological change was found. After a post-operative follow-up of at least 12 months (mean 42.5 months) all the 16 patients with a Taylor's FCD were in Engel's Class Ia and the other 5 patients were in Engel's Classes II or III. After 6 months post-surgery EDS had disappeared in the 9 patients who presented this complaint pre-operatively. It is concluded that patients with drug-resistant, disabling sleep-related seizures of frontal lobe origin should be considered for resective surgery, which may provide excellent results both on seizures and on epilepsy-related sleep disturbances. An accurate pre-surgical evaluation, which often requires invasive EEG recording, is mandatory to define the EZ. Further investigation is needed to explain the possible causal relationships between FCD, particularly Taylor-type, and sleep-related seizures, as observed in this cohort of NFLE patients.

332 EFFECT OF DIFFERENT PIG OOCYTE ACTIVATION PROTOCOLS ON EMBRYO DEVELOPMENT IN SOF AND NCSU-23

Several factors affect nuclear transfer success. These include efficient parthenogenetic activation and embryo culture medium that should efficiently support pre-implantation development of good quality blastocysts. We investigated pig oocyte activation and embryo development in SOFaa in response to ionomycin (Io = 5 µM Io for 4 min; Io° = 15 µM Io for 20 min) and electric impulse (EL; one 30-µs pulse of DC 1.5 kV cm−1 in the presence of 50 µM Ca) in combination with 2 mM 6-DMAP or 10 µg mL−1 cycloheximide (CHX) +5 µg mL−1 cytochalasin B (CB) for 4 h. In addition, we studied the effect of elevated (1 mM) (Cheong et al. 2002 Mol. Reprod. Dev. 61, 488) in comparison with 50 µM Ca during EL activation on embryo development in SOFaa and NCSUaa-23. Porcine oocytes were recovered from slaughtered donors and matured in vitro for 44 h in DMEM-F12 supplemented with 10% FCS, 0.05 IU LH and FSH (Menogon®, Ferring, Milan, Italy), 0.3 mM cystine, 0.5 mM cysteamine, 50 ng mL−1 long-EGF, 100 ng mL−1 long-IGF1, 5 ng mL−1 bFGF (Sigma-Aldrich, Milan, Italy) in 5% CO2 at 38.5°C. The rates of cleavage, blastocyst formation (BL) and BL cell number on Day 7 (BL-D7) were recorded. All experiments were done with 3 replicates. The data were compared by chi-square test. There was no difference in the ability of Io (all groups) and EL + CB activated oocytes to cleave, whereas the additional treatment of EL-activated oocytes with DMAP and CHX + CB significantly increased cleavage. Io activation resulted in poor blastocyst development in comparison with all EL-activated groups (see Table 1). When calcium levels were elevated during EL activation, significantly more embryos developed in SOFaa (35.6%, n = 191 vs. 26%, n = 192; P &lt; 0.05), but no differences were observed with culture in NCSUaa-23 (about 56%). The BL rate was significantly higher in NCSUaa-23 vs. SOFaa (55.9%, n = 68 vs. 34.8%, n = 69, respectively); however, the BL total cell number was significantly higher in SOFaa (58 ± 18, n = 40 vs. 86 ± 35, n = 56, respectively; P &lt; 0.05). In conclusion, we have found that SOFaa and NCSUaa-23 differ in ability to support pig parthenogenetic embryo development. EL activation combined with elevated Ca significantly increased the embryo developmental capacity in SOFaa but not in NCSUaa-23. NCSUaa-23 was more efficient for embryo culture, whereas SOF produced BLs of higher quality. Table 1.Effect of activation protocol on the development of pig parthenogenetic embryos in SOFaa This work was supported by grants ISS-CS11 and Fondazione Cariplo.

295 INFLUENCE OF FERTILIZATION MEDIUM ON THE INCIDENCE OF POLYSPERMY IN THE PIG

The in vitro production of embryos is well established in most domestic species including cattle, pigs, sheep, and goats. However, a major problem of IVF in the pig is the high incidence of polyspermy. In our laboratory, we investigated the effect of 2 different media, TALP and SOFaa, on the rate of fertilization and polyspermy of pig oocytes. Preliminary experiments indicated that TALP provided the highest fertilization but also the highest polyspermy rates, as reported in the literature (Coy et al. 2002 Reproduction 124, 279–288). By contrast, much lower polyspermy rates but also much lower fertilization rates were obtained in SOFaa. Therefore, we made a direct comparison between the 2 media and a third medium prepared by mixing TALP and SOFaa equally (1 : 1 TALP–SOF) and using 2 different boars for IVF. Porcine oocytes were recovered from slaughtered donors and matured in vitro for 40 to 44 h in DMEM-F12 supplemented with 10% FCS, 0.05 IU of LH and FSH (Menogon; Ferring, Milan, Italy), 0.3 mM cystine, 0.5 mM cysteamine, 50 ng mL−1 of long-EGF, 100 ng mL−1 of long-IGF1, and 5 ng mL−1 of bFGF (Sigma-Aldrich, Milan, Italy) in 5% CO2 at 38.5°C. Boar frozen–thawed semen was separated on a Percoll gradient (45–90%) and diluted in TALP or in SOFaa with PHE (penicillamine, hypotaurine, epinefrine) and heparin (1 µg mL−1) to concentrations ranging from 0.01 to 0.15 million sperm/mL. The concentration was optimized for each boar and medium: For boar A, the concentration was 0.015 million sperm/mL for medium TALP and TALP–SOF and 0.15 million sperm/mL for medium SOF; for boar B, the concentration was 0.1 million sperm/mL for medium TALP and TALP–SOF and 0.15 million sperm/mL for medium SOF. The oocytes were co-incubated with the sperm suspension for 18 h and then were denuded of the surrounding cumulus and fixed in acetic acid–ethanol (1 : 3) for 48 h. Finally, they were stained with lacmoid and observed under phase-contrast microscopy. The data are shown in Table 1 and were compared by a chi-squared test. Our results indicated that TALP was the most efficient medium for pig IVF but over 50% of the oocytes were polyspermic. By contrast, very low polyspermy, but also very low fertilization, was observed in SOF medium for both boars A and B. Interestingly, the empirical approach of mixing the 2 media 50% each provided a dramatic reduction of the polyspermy rate while maintaining the fertilization rate at over 60% in both boars. At present, experiments are ongoing to clarify the role of specific components of the 2 media on the fertilization and polyspermy rates of pig oocytes. Table 1.Effect of different media on fertilization and polyspermy rates with 2 different boars This work was supported by grants from EUROSTELLS-ESF (ERAS-CT-2003-980409).

257 EXPRESSION PROFILING OF GENES CRUCIAL FOR LINEAGE DETERMINATION IN IN VITRO-DERIVED EARLY BOVINE EMBRYOS

In the early blastocyst, lineage segregation depends on the expression of several key specific transcription factors. In the mouse, commitment to inner cell mass (ICM), lineage is positively regulated by Oct-4, a repressor of trophectoderm (TE) cell fate, and Nanog, which inhibits the formation of extra-embryonic and primitive endoderm. Cdx2, a caudal-type homeodomain protein, is specifically expressed in the nascent TE. The mechanisms that drive Cdx2 segregation to the outside cells are still unclear. However, the expression of Fgf Receptor 2 (FgfR2), restricted to the outside cells, and the role for its ligand, Fgf4, in promoting TE development, suggest that this signalling pathway may act upstream or in parallel with Cdx2. Little information is available on these genes in bovine; therefore the aims of the present study were as follows: (a) to identify and characterize the expression profiles of Cdx2 and FgfR2 variants (IIIc and IIIb) in bovine oocytes and pre-implantation embryos; and (b) to compare their expression patterns in ICM and TE with that of Oct-4 and Nanog. Bovine oocytes and embryos were obtained by in vitro maturation and fertilization; blastocysts at Day 7 post-insemination underwent microsurgery to separate TE from ICM. RNA was isolated from MII oocytes; 2-, 4-, 8-, and 16-cell embryos; morulae; blastocysts; ICMs; and TEs. Semi-quantitative analysis of Cdx2 and FgfR2 expression in oocytes and embryos was performed in the exponential phase of PCR amplification with rabbit globin as exogenous control. In order to exclude false negative results, PCR amplification in isolated TE and ICM was extended to the plateau phase for all genes considered. Fragment identity was confirmed by sequencing. Comparison of bovine Cdx2 cDNA sequence (EMBL AM293662) with databases revealed a 91% and 87% homology with human and mouse, respectively. Cdx2 expression was not detectable in MII oocytes, but increased in 2-cell embryos. Transcript levels decreased at the 4- and 8-cell stages and then increased again in the blastocyst. FgfR2 variants were present as both maternal and embryonic transcripts, because they were detectable throughout pre-implantation development. Cdx2 and FgfR2 IIIc and IIIb expression was restricted to TE cells. Nanog was detected only in ICM, whereas Oct-4 was expressed in both lineages, as previously described in bovine (van Eijk et al. 1999 Bio. Reprod. 60, 1093-1103). In conclusion, the expression profiles of Nanog, Cdx2, and FgfR2 in bovine pre-implantation embryos follow the pattern previously described in the mouse. Their differentially segregated expression is consistent with their role as selector factors of ICM vs. TE fates. The significance of Oct-4 ubiquitous distribution still remains to be elucidated. This work was supported by FIRB RBNE01HPMX_005, TECLA-MIUR, and EUROSTELLS-ESF.

202 INNER CELL MASS EXCHANGE IN SHEEP EMBRYOS

The presence of a developmental axis in the mammalian oocyte/embryo is still a controversial issue (Plusa 2005 Nature 17, 391–395). However, pre-established or not, mammalian blastocysts display a clear asymmetry with distinct embryonic and abembryonic poles. The present emphasis on ‘mosaic’ development in mammalian embryos is in contrast with classical embryological work, aimed at cell lineage analysis, where manipulation procedures severely perturbed the natural blastocyst asymmetry (Gardner 2001 RBM Online 4, 46–51). However, all of the experimental work thus far has been carried out on mouse embryos. In our work, we designed experiments to determine whether sheep embryos subjected to inner cell mass (ICM) transfer retain normal developmental competence. In vitro-derived sheep blastocysts (Ptak et al. 2003 Biol. Reprod. 69, 278–285) were manipulated with a Narishige micromanipulator fitted to a inverted Nikon microscope. ICMs were dissected with a blade, and the trophoblastic vesicle and ICMs were cultured in SOFaa plus 10% FCS. After re-expansion, trophoblastic vesicles were injected with ICMs by means of a bevelled pipette and cultured overnight with SOFaa plus 10% FCS. From a total of 35 blastocysts used, 25 re-expanded following injection, and 20 of them showed ICMs adherent to the trophoblast. Seven blastocysts were transferred into synchronized ewes 7 days after estrus, and monitored every month with an Aloka linear probe (7–5 MHz; Aloka Co., Ltd., Tokyo, Japan). Twenty-one in vitro-produced (IVP) embryos were transferred as a control. Three ewes receiving ICM-exchanged blastocysts were pregnant at the first scanning, and all delivered normal offspring (two female and one male lamb; weight: 3.54 ± 0.358 kg). These data demonstrate that dramatic alteration of the blastocyst structure does not compromise its developmental potential. Our efficiency in terms of offspring is lower compared with control IVP embryos, and also compared to data obtained in mice (Papaioannou 1982 J. Embryol. Exp. Morph. 68, 199–209), but technical improvements are expected to reduce such a gap. In conclusion, we demonstrated the feasibility of ICM/trophoblastic exchange in sheep blastocysts; these results might have important application for technologies like somatic cell nuclear transfer (SCNT). Common features of SCNT clones are placental abnormalities in early (DeSousa et al. 2001 Biol. Reprod. 65, 23–30) and late pregnancies (Loi et al. 2006 Theriogenology 65, 1110–1121). The transfer of ICM from cloned embryos to normal trophoblastic vesicles, although ineffective in cattle (Murakami et al. 2006 Cloning Stem Cells 8, 51–69), might be worth trying on sheep, a species where post-natal mortality in clones is a serious issue. Table 1.Development to term of manipulated and cloned embryos Part of this work was supported by EUROSTELLS-European Science Foundation.

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

Oocyte cryopreservation is a potentially valuable way of preserving the female germ line. However, the developmental competence of cryopreserved oocytes is presently poor. This study investigated whether the morphology of the cumulus complex surrounding an immature equine oocyte and/or the oocyte’s stage of maturation affect its cryopreservability. Compact (Cp) and expanded (Ex) cumulus oocyte complexes (COCs) were vitrified either shortly after recovery (germinal vesicle stage, GV) or after maturationin vitro(IVM); cryoprotectant-treated and -untreated non-frozen oocytes served as controls. In Experiment I, oocytes maturedin vitroand then vitrified, or vice versa, were examined for maturation stage and meiotic spindle quality. Cp and Ex COCs vitrified at the GV stage matured at similar rates during subsequent IVM (41 vs 46% MII), but meiotic spindle quality was better for Cp than Ex (63 vs 33% normal spindles). Vitrifying oocytes after IVM resulted in disappointing post-warming spindle quality (32 vs 28% normal for Cp vs Ex). In Experiment II, oocytes from Cp and Ex COCs vitrified at the GV or MII stages were fertilized by intracytoplasmic sperm injection (ICSI) and monitored for cleavage and blastocyst formation. Oocytes vitrified prior to IVM yielded higher cleavage rates (34 and 27% for Cp and Ex COCs) than those vitrified after IVM (16 and 4%). However, only one blastocyst was produced from a sperm-injected vitrified–warmed oocyte (0.4 vs 9.3% and 13% blastocysts for cryoprotectant-exposed and -untreated controls). It is concluded that, when vitrification is the chosen method of cryopreservation, Cp equine COCs at the GV stage offer the best chance of an MII oocyte with a normal spindle and the potential for fertilization; however, developmental competence is still reduced dramatically.