Name: human blastocyst biopsy and vitrification
Uploaded: 2019-07-26T12:30:00
Description: Watch this Scientific Journal Video about Human Blastocyst Biopsy and Vitrification at JoVE.com

AG and RM collected the data and drafted the manuscript. DC analyzed the data, drafted the representative results, performed the statistics and revised the manuscript. FMU and LR provided critical discussion of the results and of the whole manuscript.

The protocol for human blastocyst biopsy, here described, follows the guidelines of G.EN.E.R.A. Human Research Ethic Committee.
NOTE: Refer to the Table of Materials for materials required. Further material required entails laboratory footwear and outfit, surgical facemask, hair cover, surgical gloves, a permanent non-toxic marker, forceps and disinfectant. The use of surgical gown, disposable surgical gloves, facemask, hair cover is mandatory to prevent risk ...

<ol>
	<li>Glujovsky, D., Farquhar, C., Quinteiro Retamar, A. M., Alvarez Sedo, C. R., Blake, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleavage+stage+versus+blastocyst+stage+embryo+transfer+in+assisted+reproductive+technology.">Cleavage stage versus blastocyst stage embryo transfer in assisted reproductive technology.</a> Cochrane Database of Systematic Reviews. (6), CD002118 (2016).</li><li>Dahdouh, E. M., Balayla, J., Garcia-Velasco, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+chromosome+screening+improves+embryo+selection:+a+meta-analysis.">Comprehensive chromosome screening improves embryo selection: a meta-analysis.</a> Fertility and Sterility. 104 (6), 1503-1512 (2015).</li><li>Cimadomo, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Impact+of+Biopsy+on+Human+Embryo+Developmental+Potential+during+Preimplantation+Genetic+Diagnosis.">The Impact of Biopsy on Human Embryo Developmental Potential during Preimplantation Genetic Diagnosis.</a> Biomedical Research International. 2016, 7193075 (2016).</li><li>Capalbo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+between+standard+blastocyst+morphology,+euploidy+and+implantation:+an+observational+study+in+two+centers+involving+956+screened+blastocysts.">Correlation between standard blastocyst morphology, euploidy and implantation: an observational study in two centers involving 956 screened blastocysts.</a> Human Reproduction. 29 (6), 1173-1181 (2014).</li><li>Capalbo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementing+PGD/PGD-A+in+IVF+clinics:+considerations+for+the+best+laboratory+approach+and+management.">Implementing PGD/PGD-A in IVF clinics: considerations for the best laboratory approach and management.</a> Journal of Assisted Reproduction and Genetics. , (2016).</li><li>McArthur, S. J., Leigh, D., Marshall, J. T., de Boer, K. A., Jansen, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pregnancies+and+live+births+after+trophectoderm+biopsy+and+preimplantation+genetic+testing+of+human+blastocysts.">Pregnancies and live births after trophectoderm biopsy and preimplantation genetic testing of human blastocysts.</a> Fertility and Sterility. 84 (6), 1628-1636 (2005).</li><li>Kokkali, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Birth+of+a+healthy+infant+following+trophectoderm+biopsy+from+blastocysts+for+PGD+of+beta-thalassaemia+major.">Birth of a healthy infant following trophectoderm biopsy from blastocysts for PGD of beta-thalassaemia major.</a> Human Reproduction. 20 (7), 1855-1859 (2005).</li><li>Rienzi, L., Ubaldi, F., Anniballo, R., Cerulo, G., Greco, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preincubation+of+human+oocytes+may+improve+fertilization+and+embryo+quality+after+intracytoplasmic+sperm+injection.">Preincubation of human oocytes may improve fertilization and embryo quality after intracytoplasmic sperm injection.</a> Human Reproduction. 13 (4), 1014-1019 (1998).</li><li>Wale, P. L., Gardner, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+chemical+and+physical+factors+on+mammalian+embryo+culture+and+their+importance+for+the+practice+of+assisted+human+reproduction.">The effects of chemical and physical factors on mammalian embryo culture and their importance for the practice of assisted human reproduction.</a> Human Reproduction Update. 22 (1), 2-22 (2016).</li><li>Rienzi, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oocyte,+embryo+and+blastocyst+cryopreservation+in+ART:+systematic+review+and+meta-analysis+comparing+slow-freezing+versus+vitrification+to+produce+evidence+for+the+development+of+global+guidance.">Oocyte, embryo and blastocyst cryopreservation in ART: systematic review and meta-analysis comparing slow-freezing versus vitrification to produce evidence for the development of global guidance.</a> Human Reproduction Update. 23 (2), 139-155 (2017).</li><li>Cimadomo, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Associations+of+blastocyst+features,+trophectoderm+biopsy+and+other+laboratory+practice+with+post-warming+behavior+and+implantation.">Associations of blastocyst features, trophectoderm biopsy and other laboratory practice with post-warming behavior and implantation.</a> Human Reproduction. , (2018).</li><li>Evans, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fresh+versus+frozen+embryo+transfer:+backing+clinical+decisions+with+scientific+and+clinical+evidence.">Fresh versus frozen embryo transfer: backing clinical decisions with scientific and clinical evidence.</a> Human Reproduction Update. 20 (6), 808-821 (2014).</li><li>Capalbo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consistent+and+reproducible+outcomes+of+blastocyst+biopsy+and+aneuploidy+screening+across+different+biopsy+practitioners:+a+multicentre+study+involving+2586+embryo+biopsies.">Consistent and reproducible outcomes of blastocyst biopsy and aneuploidy screening across different biopsy practitioners: a multicentre study involving 2586 embryo biopsies.</a> Human Reproduction. 31 (1), 199-208 (2016).</li><li>Cimadomo, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failure+mode+and+effects+analysis+of+witnessing+protocols+for+ensuring+traceability+during+PGD/PGS+cycles.">Failure mode and effects analysis of witnessing protocols for ensuring traceability during PGD/PGS cycles.</a> Reproductive Biomedicine Online. 33 (3), 360-369 (2016).</li><li>Gardner, D. K., Schoolcraft, B., Jansen, R., Mortimer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Towards Reproductive Certainty: Infertility and Genetics Beyond 1999. , 377-388 (1999).</li><li>Cimadomo, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inconclusive+chromosomal+assessment+after+blastocyst+biopsy:+prevalence,+causative+factors+and+outcomes+after+re-biopsy+and+re-vitrification.+A+multicenter+experience.">Inconclusive chromosomal assessment after blastocyst biopsy: prevalence, causative factors and outcomes after re-biopsy and re-vitrification. A multicenter experience.</a> Human Reproduction. , (2018).</li><li>de Boer, K. A., Catt, J. W., Jansen, R. P., Leigh, D., McArthur, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moving+to+blastocyst+biopsy+for+preimplantation+genetic+diagnosis+and+single+embryo+transfer+at+Sydney+IVF.">Moving to blastocyst biopsy for preimplantation genetic diagnosis and single embryo transfer at Sydney IVF.</a> Fertility and Sterility. 82 (2), 295-298 (2004).</li><li>Capalbo, A., Rienzi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mosaicism+between+trophectoderm+and+inner+cell+mass.">Mosaicism between trophectoderm and inner cell mass.</a> Fertility and Sterility. 107 (5), 1098-1106 (2017).</li><li>McCoy, R. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+of+Selection+against+Complex+Mitotic-Origin+Aneuploidy+during+Preimplantation+Development.">Evidence of Selection against Complex Mitotic-Origin Aneuploidy during Preimplantation Development.</a> PLoS Genetics. 11 (10), e1005601 (2015).</li><li>Scott, R. T., Upham, K. M., Forman, E. J., Zhao, T., Treff, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleavage-stage+biopsy+significantly+impairs+human+embryonic+implantation+potential+while+blastocyst+biopsy+does+not:+a+randomized+and+paired+clinical+trial.">Cleavage-stage biopsy significantly impairs human embryonic implantation potential while blastocyst biopsy does not: a randomized and paired clinical trial.</a> Fertility and Sterility. 100 (3), 624-630 (2013).</li><li>Lee, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+births+after+transfer+of+rebiopsy+and+revitrification+of+blastocyst+that+had+&#8220;no+diagnosis&#8221;+following+trophectoderm+biopsy.">Live births after transfer of rebiopsy and revitrification of blastocyst that had &#8220;no diagnosis&#8221; following trophectoderm biopsy.</a> Fertility and Sterility. 106 (3), e164 (2016).</li><li>Capalbo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnostic+efficacy+of+blastocoel+fluid+and+spent+media+as+sources+of+DNA+for+preimplantation+genetic+testing+in+standard+clinical+conditions.">Diagnostic efficacy of blastocoel fluid and spent media as sources of DNA for preimplantation genetic testing in standard clinical conditions.</a> Fertility and Sterility. 110 (5), 870-879 (2018).</li><li>Hammond, E. R., Shelling, A. N., Cree, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+and+mitochondrial+DNA+in+blastocoele+fluid+and+embryo+culture+medium:+evidence+and+potential+clinical+use.">Nuclear and mitochondrial DNA in blastocoele fluid and embryo culture medium: evidence and potential clinical use.</a> Human Reproduction. 31 (8), 1653-1661 (2016).</li><li>Vera-Rodriguez, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Origin+and+composition+of+cell-free+DNA+in+spent+medium+from+human+embryo+culture+during+preimplantation+development.">Origin and composition of cell-free DNA in spent medium from human embryo culture during preimplantation development.</a> Human Reproduction. 33 (4), 745-756 (2018).</li></ol>

Only well-experienced skilled embryologists who have completed their training period should perform both TE biopsy and blastocyst vitrification. Furthermore, a witness is required to monitor the procedures and guarantee an efficient traceability during i) the movements of the biopsied blastocyst from the biopsy dish (Supplementary Figure 1) to the post-biopsy dish (Supplementary Figure 1), then to the vitrification plate (Supplementary Figure 1) and lastly to the vitrifi...

The main goal of modern human embryology is to maximize the number live births per stimulated cycle and reduce costs, time and efforts to achieve a pregnancy. To accomplish this goal, validated approaches for embryo selection should be employed to identify reproductively competent embryos within a cohort obtained during an IVF cycle. According to the latest evidences, blastocyst culture1 combined with comprehensive chromosomal testing and vitrified-warmed euploid embryo transfer (ET) is the most efficient framework to increase IVF efficiency2. Clearly, aneuploidy testing requires an embryonic specimen, which at present is mostly represented from few cells retrieved from the trophectoderm (TE), i.e., the section of the blastocyst that gives origin to embryo annexes (e.g., the placenta) during pregnancy. Beyond karyotype analysis, also single gene mutations might be assessed from a TE biopsy as part of a clinical strategy known as preimplantation genetic testing (PGT; -A for aneuploidies, -SR for structural chromosomal rearrangements, -M for monogenic diseases). Other oocyte/embryo biopsy methods have been theorized and adopted clinically across the last decades, namely polar bodies biopsy and blastomere biopsy. However, their use is reduced nowadays since their procedural drawbacks (e.g., higher workload and risk for reproductive impact) and diagnostic limitations (e.g., single cell analysis issues) implicitly hinder a sufficient balance between costs, risks and benefits (for a review see3).
In this paper, one of the main protocols for TE biopsy is thoroughly described together with the subsequent vitrification, warming and transfer procedures required. The workflow here outlined is ideal for a busy PGT unit.
As already described previously by our group4,5, the procedure involves the sequential opening of the zona pellucida of fully-expanded blastocysts and removal of few TE cells (on average 7-8). Compared to the day 3 laser-assisted hatching-based blastocyst biopsy method6, this procedure might ease the daily schedule of an IVF unit where delicate procedures, such as blastocyst biopsy and vitrification, must be timely performed. As soon as the blastocyst reaches its full expansion, the biopsy can be carried out by selecting the TE cells to remove, thereby preventing the risk of herniation of the inner cell mass (ICM), which would otherwise render the procedure challenging. In literature, a third protocol of blastocyst biopsy has been also described, which involves laser-assisted hatching being performed once the embryo has already reached the blastocyst stage, few hours before the procedure5,7. However, this approach is more time-consuming and mainly suits IVF units that are implementing TE biopsy in the hands of limitedly experienced operators and in view of a moderate-low daily workload.
Intracytoplasmatic sperm injection (ICSI)8 should be a consolidated technique if aiming at conducting genetic analyses in IVF. Similarly, a proper culture system to safely harvest embryos to the blastocyst stage is crucial for the implementation of TE biopsy strategy. An adequate number of incubators, as well as the use of low oxygen tension are key prerequisites to this end, not to compromise the blastocyst rate9. At the same time, an efficient cryopreservation program is needed to safely manage a PGT cycle. In the last decade, the implementation of vitrification has boosted embryo cryo-survival rates even up to &#62;99%10,11. This provided sufficient time to perform genetic testing and postpone embryo transfer to the following menstrual cycle, on a non-stimulated and probably more receptive endometrium12.
Both TE biopsy and vitrification are demanding tasks requiring stringent skills and their effectiveness might vary across unexperienced operators. A specific training period is therefore advocated before allowing each operator to perform these procedures clinically; moreover, the maintenance of the operators&#8217; skills should be assessed periodically by monitoring key performance indicators (KPI) for cryopreservation and biopsy procedures. Each IVF clinic should set internal KPIs to this end, which must approximate the ones published by international consortia and/or the outcomes published by reference laboratories.
TE biopsy, vitrification-warming and witnessing procedures are validated techniques at our unit, that have been standardized across all the operators involved as reported in three previous publications11,13,14.

<table>
	<tbody>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cold tube rack</td>
			<td>Biocision</td>
			<td>XTPCR96</td>
			<td></td>
		</tr>
		<tr>
			<td>Electronic pipette controller</td>
			<td>Fisher Scientific</td>
			<td>710931</td>
			<td></td>
		</tr>
		<tr>
			<td>Flexipet adjustable handle set</td>
			<td>Cook</td>
			<td>G18674</td>
			<td>Stripper holder</td>
		</tr>
		<tr>
			<td>Gilson Pipetman</td>
			<td>Gilson</td>
			<td>66003</td>
			<td>p20</td>
		</tr>
		<tr>
			<td>IVF Electronic Witness System</td>
			<td>CooperSurgical Fertility &#38; Genomic Solutions</td>
			<td></td>
			<td>RI Witness ART Management System</td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Nikon</td>
			<td>Eclipse TE2000-U</td>
			<td></td>
		</tr>
		<tr>
			<td>Laminar Flow Hood</td>
			<td>IVF TECH</td>
			<td></td>
			<td>Grade A air flow</td>
		</tr>
		<tr>
			<td>Laser objective</td>
			<td>RI</td>
			<td>Saturn 5</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinjectors</td>
			<td>Nikon Narishige</td>
			<td>NT-88-V3</td>
			<td></td>
		</tr>
		<tr>
			<td>Mini centrifuge for PCR tubes</td>
			<td>Eppendorf</td>
			<td>CSLQSPIN</td>
			<td>for 0.2ml PCR tubes</td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Leica</td>
			<td>Leica M80</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermostat</td>
			<td>Panasonic</td>
			<td>MCO-5AC-PE</td>
			<td></td>
		</tr>
		<tr>
			<td>Tri-gas incubator</td>
			<td>Panasonic</td>
			<td>MCO-5M-PE</td>
			<td>02/CO2</td>
		</tr>
		<tr>
			<td>Consumables</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Biopsy pipette</td>
			<td>RI</td>
			<td>7-71-30FB35720</td>
			<td>30&#181;m ID, flat 35&#176;C</td>
		</tr>
		<tr>
			<td>Cryolock</td>
			<td>Cryolock</td>
			<td>CL-R-CT</td>
			<td></td>
		</tr>
		<tr>
			<td>CSCM complete</td>
			<td>Irvine Scientific</td>
			<td>90165</td>
			<td>IVF culture medium supplemented with HSA</td>
		</tr>
		<tr>
			<td>Embryo Transfer Catheter</td>
			<td>Cook</td>
			<td>G17934</td>
			<td></td>
		</tr>
		<tr>
			<td>Flexipet pipette</td>
			<td>Cook</td>
			<td>G26712</td>
			<td>140&#181;m stripping pipette tip</td>
		</tr>
		<tr>
			<td>Flexipet pipette</td>
			<td>Cook</td>
			<td>G46020</td>
			<td>300&#181;m stripping pipette tips</td>
		</tr>
		<tr>
			<td>Holding pipette</td>
			<td>RI</td>
			<td>7-71-IH35/20</td>
			<td>30&#181;m ID, flat 35&#176;C</td>
		</tr>
		<tr>
			<td>Human Serum Albumin</td>
			<td>Irvine Scientific</td>
			<td>9988</td>
			<td></td>
		</tr>
		<tr>
			<td>IVF One well dish</td>
			<td>Falcon</td>
			<td>353653</td>
			<td></td>
		</tr>
		<tr>
			<td>Mineral Oil for embryo culture</td>
			<td>Irvine Scientific</td>
			<td>9305</td>
			<td></td>
		</tr>
		<tr>
			<td>Modified HTF Medium</td>
			<td>Irvine Scientific</td>
			<td>90126</td>
			<td>Hepes-Buffered medium</td>
		</tr>
		<tr>
			<td>Nuclon Delta Surface</td>
			<td>Thermofisher scientific</td>
			<td>176740</td>
			<td>IVF dish 4-well plate with sliding lid</td>
		</tr>
		<tr>
			<td>Primaria Cell culture dish</td>
			<td>Corning</td>
			<td>353802</td>
			<td>60x15mm</td>
		</tr>
		<tr>
			<td>Reproplate</td>
			<td>Kitazato</td>
			<td>83016</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipette</td>
			<td>Falcon</td>
			<td>357551</td>
			<td>10ml</td>
		</tr>
		<tr>
			<td>Sterile disposable Gilson tips</td>
			<td>Eppendorf</td>
			<td>0030 075.021</td>
			<td>200&#181;l</td>
		</tr>
		<tr>
			<td>Tubing Kit</td>
			<td>Provided by the genetic lab</td>
			<td></td>
			<td>PCR tubes (0.2mL), loading solution, biopsy washing solution</td>
		</tr>
		<tr>
			<td>Vitrification media</td>
			<td>Kitazato</td>
			<td>VT801</td>
			<td>Equilibration and vitrification solutions</td>
		</tr>
		<tr>
			<td>Warming media</td>
			<td>Kitazato</td>
			<td>VT802</td>
			<td>Thawing and dilution solutions</td>
		</tr>
	</tbody>
</table>

human blastocyst biopsy and vitrification

Blastocyst biopsy is performed to obtain a reliable genetic diagnosis during IVF cycles with preimplantation genetic testing. Then, the ideal workflow entails a safe and efficient vitrification protocol, due to the turnaround time of the diagnostic techniques and to transfer the selected embryo(s) on a physiological endometrium in a following natural cycle. A biopsy approach encompassing the sequential opening of the zona pellucida and retrieval of 5-10 trophectoderm cells (ideally 7-8) limits both the number of manipulations required and the exposure of the embryo to sub-optimal environmental conditions. After proper training, the technique was reproducible across different operators in terms of timing of biopsy (~8 min, ranging 3-22 min based on the number of embryos to biopsy per dish), conclusive diagnoses obtained (~97.5%) and live birth rates after vitrified-warmed euploid blastocyst transfer (&#62;40%). The survival rate after biopsy, vitrification and warming was as high as 99.8%. The re-expansion rate at 1.5 h from warming was as high as 97%, largely dependent on the timing between biopsy and vitrification (ideally &#8804;30 min), blastocyst morphological quality and day of biopsy. In general, it is better to vitrify a collapsed blastocyst; therefore, in non-PGT cycles, laser-assisted artificial shrinkage might be performed to induce embryo collapse prior to cryopreservation. The most promising future perspective is the non-invasive analysis of the IVF culture media after blastocyst culture as a putative source of embryonic DNA. However, this potential avant-garde is still under investigation and a reliable protocol yet needs to be defined and validated.

Figure 6 represents a scheme of all the outcomes of a biopsy procedure that can be adopted to standardize the protocol and monitor the performance of each operator. The main procedural outcome is the timing to complete the biopsy/biopsies; the main technical outcome is the quality of the plot produced after genetic testing that might result in either a conclusive or inconclusive diagnosis, the latter of which requires a re-biopsy of the undiagnosed blastocyst...

Watch this Scientific Journal Video about Human Blastocyst Biopsy and Vitrification at JoVE.com

Human Blastocyst Biopsy and Vitrification

Blastocyst biopsy and vitrification are required to efficiently conduct preimplantation genetic testing. An approach entailing the sequential opening of the zona pellucida and retrieval of 7-8 trophectoderm cells in day 5-7 post-insemination limits both the number of manipulations required and the exposure of the embryo to sub-optimal environmental conditions.

Blastocyst biopsy is performed to obtain a reliable genetic diagnosis during IVF cycles with preimplantation genetic testing. Then, the ideal workflow ...

Both blastocyst biopsy and vitrification have been a revolution in IVF, in vitro fertilization, allowing embryologists from all around the world to perform preimplantation genetic testing on human embryos with minimal risk for the embryo. Trophectoderm biopsy has allowed the retrieval of about seven cells from a fully grown embryo, thereby enabling robust downstream genetic analysis. Moreover, no impact has been shown, to date, for this approach.The clinical efficiency of this workflow allows patients with monogenic conditions and all those patients with increased risk of chromosomal abnormalities within their blastocyst to benefit from preimplantation genetic testing. There is still room for improving the current strategies of embryo selection. For instance, miRNomic and proteomic profiling represent intriguing options to complement preimplantation genetic testing on a single trophectoderm biopsy.Unexperienced operators often struggle with opening and penetrating the zona pellucida. It's just a matter of focus. The blastocyst, laser objective, and pipettes should be on the same focal plane.After labeling the biopsy dish with the patient's details, with a permanent, non-toxic marker, number each 10-microliter drop of HEPES-buffered medium with the embryo and cycle ID.Using a 300-micrometer stripping pipette, transfer a viable, fully expanded blastocyst to the first drop of the biopsy dish and rinse the drop to remove the excess culture medium, before moving the blastocyst into the second drop in the dish. Place the dish under an inverted microscope, and prime the biopsy pipette with medium from the third drop of the biopsy dish. Under a 20 times magnification, orient the blastocyst to obtain a clear view of the inner cell mass at seven o'clock, and secure the embryo on the holding pipette.Focus on the zona pellucida so that both the pipettes and the blastocyst are on the same focal plane. Switch to the laser objective, and position the laser pointer on the zona pellucida at the opposite side of the inner cell mass. Drill the zona pellucida with two to three laser pulses, and gently press the biopsy pipette against the zona pellucida to allow medium to be blown through the breach to detach the trophectoderm cells from the internal surface.When the trophectoderm is detached, enter through the hole and aspirate seven to eight trophectoderm cells into the biopsy pipette with gentle suction. While applying a moderate suction to stretch the target cells, slightly move the biopsy pipette backwards and direct the laser towards the thinnest part of the aspirated cells. Fire two to five laser pulses at the junctions between the cells to separate the target cells from the body of the embryo.When the trophectoderm fragment has been separated from the blastocyst, release the fragment into the same biopsy drop far from the blastocyst to prevent the fragment from being sucked back into the biopsy pipette. Release the blastocyst from the holding pipette, and promptly raise both pipettes to prevent the fragment from sticking to pipettes. Then image the biopsied fragment for quality control purposes.When all of the blastocysts have been biopsied as just demonstrated, move the biopsy dish back to the laminar flow hood and label the post-biopsy culture dish with the couple ID and each drop with the embryo and cycle IDs. In presence of a witness, rinse the blastocyst in clean IVF medium and move the blastocyst to its corresponding drop in the post-biopsy dish. Then place the post-biopsy dish to a 37-degree Celsius, 6%carbon dioxide, and 5%oxygen incubator.In the presence of the witness and inside a laminar flow hood at room temperature, label the PCR tubes with a permanent, non-toxic marker. Label the lid of a 60 x 15-millimeter tubing culture dish with the biopsied embryo IDs, and add two 10-microliter drops of biopsy washing solution to the dish. Prime a 140-micrometer stripping pipette with biopsy washing solution from the second drop of the tubing dish under the stereo microscope to visualize the trophectoderm fragments.Gently release some biopsy washing solution upon the trophectoderm fragment, and load the fragment into the stripping pipette. Move the fragment to the second drop of biopsy washing solution, and carefully rinse the tissue two to three times. Transfer the trophectoderm fragment to the bottom of the appropriately labeled PCR tube with loading solution, taking care to avoid touching the walls of the tube with the tip of the stripping pipette.When all of the fragments have been added to their tubes, spin all of the tubes in a mini centrifuge for a few seconds to sediment the fragments. Then store the samples at minus 20 degrees Celsius until they are shipped to the referring genetic laboratory for testing. Within 30 minutes of trophectoderm biopsy, label a vitrification plate with the patient's details and the IDs of the blastocysts that must be vitrified.Using special cold temperature-resistant cryolabels, label the vitrification supports with patient's name and surname, couple ID, ID of the embryo that will be loaded on to it, and the date of the procedure. At room temperature, dispense 300 microliters of equilibration solution for each blastocyst that will be vitrified and, in the presence of a witness, use a 300-micrometer stripping pipette to move the blastocyst into one volume of equilibration solution. Leave the blastocyst in the equilibration solution for 13 to 15 minutes.After an initial shrinkage of the volume, a gradual re-expansion will be observed. At the end of the equilibration, add 300 microliters of vitrification solution to the second well of the vitrification plate and transfer the completely re-expanded blastocyst to the vitrification solution for one minute. At the end of the incubation, rinse the blastocyst to dilute the equilibration solution and, in the presence of a witness, load the blastocyst on the vitrification support.Remove the excess of vitrification solution. A subtle film of solution should surround the blastocyst. Plunge the vitrification support into liquid nitrogen, and vigorously move the support to reduce the risk of bubble formation close to the specimen.Then place the protective cap on the support while the vitrification support is still submerged in liquid nitrogen. Of the 1, 544 trophectoderm biopsy procedures conducted over this representative two-year period, between one to four blastocysts were biopsied per procedure for between three to 22 minutes per procedure. In these plots, the mean timing of the biopsy for each operator along the study trimesters are shown, with a mean overall value of 8.24 minutes.It is helpful to acquire an image of each biopsied fragment for quality control purposes to evaluate whether the cause of inconclusive diagnoses was imputable to the dimension and/or quality of the fragment, to the tubing, or to some issues in the processing of the sample in the genetic laboratory. In this study, 572 euploid blastocysts were warmed to undergo an embryo transfer after a diagnosis of euploidy. All the blastocysts vitrified within 30 minutes, with 2.4%of the blastocysts not re-expanding between 31 and 90 minutes and 4.9%not re-expanding beyond 90 minutes from rewarming.Especially for poor quality and/or day seven blastocysts, the timing between biopsy and vitrification seems crucial to achieve re-expansion after warming. Take care to focus before opening the zona pellucida when exposing the junction between the trophectoderm cell and firing, and take care also to prevent blastocyst re-expansion before vitrification. Two other blastocyst biopsy approaches exist, both entailing zona pellucida opening and waiting for a spontaneous arching of the trophectoderm cells.These approaches are easier but require more manipulations and are more time-consuming. The efficacy of this workflow allows the implementation of molecular technologies in IVF in order to try to select the blastocyst with the highest chance to implant before the embryo transfer. Remember not to use any device or solution that might be toxic to the embryos and to prevent DNA contamination by using DNA-free materials.

human-blastocyst-biopsy-and-vitrification

Research

JoVE Journal

Developmental Biology

Isolation and Quantitative Immunocytochemical Characterization of Primary Myogenic Cells and Fibroblasts from Human Skeletal Muscle

The repair and regeneration of skeletal muscle requires the action of satellite cells, which are the resident muscle stem cells. These can be isolated from human muscle biopsy samples using enzymatic digestion and their myogenic properties studied in culture. Quantitatively, the two main adherent cell types obtained from enzymatic digestion are: (i) the satellite cells (termed myogenic cells or muscle precursor cells), identified initially as CD56+ and later as CD56+/desmin+ cells and (ii) muscle-derived fibroblasts, identified as CD56&#8211; and TE-7+. Fibroblasts proliferate very efficiently in culture and in mixed cell populations these cells may overrun myogenic cells to dominate the culture. The isolation and purification of different cell types from human muscle is thus an important methodological consideration when trying to investigate the innate behavior of either cell type in culture. Here we describe a system of sorting based on the gentle enzymatic digestion of cells using collagenase and dispase followed by magnetic activated cell sorting (MACS) which gives both a high purity (&#62;95% myogenic cells) and good yield (~2.8 x 106 &#177; 8.87 x 105 cells/g tissue after 7 days in vitro) for experiments in culture. This approach is based on incubating the mixed muscle-derived cell population with magnetic microbeads beads conjugated to an antibody against CD56 and then passing cells though a magnetic field. CD56+ cells bound to microbeads are retained by the field whereas CD56&#8211; cells pass unimpeded through the column. Cell suspensions from any stage of the sorting process can be plated and cultured. Following a given intervention, cell morphology, and the expression and localization of proteins including nuclear transcription factors can be quantified using immunofluorescent labeling with specific antibodies and an image processing and analysis package.

The main adherent cell types derived from human muscle are myogenic cells and fibroblasts. Here, cell populations are enriched using magnetic-activated cell sorting based on the CD56 antigen. Subsequent immunolabelling with specific antibodies and use of image analysis techniques allows quantification of cytoplasmic and nuclear characteristics in individual cells.

The repair and regeneration of skeletal muscle requires the action of satellite cells, which are the resident muscle stem cells. These can be isolated ...

Three-dimensional Quantification of Dendritic Spines from Pyramidal Neurons Derived from Human Induced Pluripotent Stem Cells

Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are distributed along the dendrites. Their morphology is largely dependent on neuronal activity, and they are dynamic. Dendritic spines express glutamatergic receptors (AMPA and NMDA receptors) on their surface and at the levels of postsynaptic densities. Each spine allows the neuron to control its state and local activity independently. Spine morphologies have been extensively studied in glutamatergic pyramidal cells of the brain cortex, using both in vivo approaches and neuronal cultures obtained from rodent tissues. Neuropathological conditions can be associated to altered spine induction and maturation, as shown in rodent cultured neurons and one-dimensional quantitative analysis 1. The present study describes a protocol for the 3D quantitative analysis of spine morphologies using human cortical neurons derived from neural stem cells (late cortical progenitors). These cells were initially obtained from induced&#160;pluripotent stem cells. This protocol allows the analysis of spine morphologies at different culture periods, and with possible comparison between induced&#160;pluripotent stem cells obtained from control individuals with those obtained from patients with psychiatric diseases.

Dendritic spines of pyramidal neurons are the sites of most excitatory synapses in mammalian brain cortex. This method describes a 3D quantitative analysis of spine morphologies in human cortical pyramidal glutamatergic neurons derived from induced&#160;pluripotent stem cells.

Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are ...

Culturing Human Pluripotent and Neural Stem Cells in an Enclosed Cell Culture System for Basic and Preclinical Research

This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety cabinets (BSCs) and incubators have long been the standard for culturing and expanding cell lines for basic and preclinical research. However, as the focus of many stem cell laboratories shifts from basic research to clinical translation, additional requirements are needed of the cell culturing system. All processes must be well documented and have exceptional requirements for sterility and reproducibility. In traditional incubators, gas concentrations and temperatures widely fluctuate anytime the cells are removed for feeding, passaging, or other manipulations. Such interruptions contribute to an environment that is not the standard for cGMP and GLP guidelines. These interruptions must be minimized especially when cells are utilized for therapeutic purposes. The motivation to move from the standard BSC and incubator system to a closed system is that such interruptions can be made negligible. Closed systems provide a work space to feed and manipulate cell cultures and maintain them in a controlled environment where temperature and gas concentrations are consistent. This way, pluripotent and multipotent stem cells can be maintained at optimum health from the moment of their derivation all the way to their eventual use in therapy.

Here is a protocol to grow pluripotent stem cells (PSC) and neural stem cells (NSC) in an enclosed cell culture system that permits maximum sterility and reproducibility, replacing the traditional biosafety cabinet and incubator. This equipment meets clinical good manufacturing practice (cGMP) and clinical good lab practice (cGLP) guidelines.

This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety ...

Modified MicroSecure Vitrification: A Safe, Simple and Highly Effective Cryopreservation Procedure for Human Blastocysts

Clinical embryo vitrification evolved with the development of unique vitrification devices in the 21st century and with the misconception that ultra-rapid cooling in an &#34;open&#34; system (i.e., direct LN2 contact) was a necessity to optimize vitrification success. The dogma surrounding the importance of cooling rates led to unsafe practices subject to technical variation and to the creation of vitrification devices that disregarded important quality-control factors (e.g., ease of use, repeatability, reliability, labeling security, and storage safety). Understanding the quality-control flaws of other devices allowed for the development of a safe, secure, repeatable, and reliable &#181;S-VTF method aimed to minimize intra- and inter-technician variation. Equally important, it combined the availability of two existing FDA-compliant devices: 1) a 0.3-mL ionomeric resin embryo straw with internalized, dual-colored, tamper-proof labeling with repeatable weld seal potential; and 2) shortened, commonly-used, 300-&#181;m ID sterile flexipettes to directly load the embryo(s) in order to create a highly-effective global vitrification device. Like other aseptic, closed vitrification systems (e.g., High Security Vitrification (HSV), Rapid-i, and VitriSafe) effectively used in reproductive medicine, microSecure Vitrification (&#181;S-VTF) has proven that it can achieve high post-warming survival and pregnancy outcomes with its attention to simplicity, and reduced technical variation. Although the 0.3-mL embryo straw containing an internal hydrophobic plug was commercially replaced with a standard semen straw possessing cotton-polyvinyl pyrrolidone (PVP) plugs, it maintained its ionomeric resin composition to ensure weld sealing. However, the cotton plugs can wick out the fluid-embryo contents of the flexipettes upon contact. A modified &#181;S-VTF method was adapted to include an additional internal weld seal before the plug on the device loading side. The added technical step to the &#181;S-VTF procedure has not affected its successful application, as high survival rates (&#62; 95%) and pregnancy rates continue today.

MicroSecure Vitrification was developed as a non-commercial, aseptic closed vitrification device system that is compliant with FDA good manufacturing and tissue-handling practices. Due to the withdrawal of hydrophobic plugged embryo straws from the industry, the vitrification procedure was modified to include an inner seal before the standard internal cotton plug.

Clinical embryo vitrification evolved with the development of unique vitrification devices in the 21st century and with the misconception that ultra-rapid ...

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Notch signaling is an evolutionarily conserved cell-cell communication system used broadly in animal development and adult maintenance. Interaction of the Notch receptor with ligands from neighboring cells induces activation of the signaling pathway (trans-activation), while interaction with ligands from the same cell inhibits signaling (cis-inhibition). Proper balance between trans-activation and cis-inhibition helps establish optimal levels of Notch signaling in some contexts during animal development. Because of the overlapping expression domains of Notch and its ligands in many cell types and the existence of feedback mechanisms, studying the effects of a given post-translational modification on trans- versus cis-interactions of Notch and its ligands in vivo is difficult. Here, we describe a protocol for using Drosophila S2 cells in cell-aggregation assays to assess the effects of knocking down a Notch pathway modifier on the binding of Notch to each ligand in trans and in cis. S2 cells stably or transiently transfected with a Notch-expressing vector are mixed with cells expressing each Notch ligand (S2-Delta or S2-Serrate). Trans-binding between the receptor and ligands results in the formation of heterotypic cell aggregates and is measured in terms of the number of aggregates per mL composed of &#62;6 cells. To examine the inhibitory effect of cis-ligands, S2 cells co-expressing Notch and each ligand are mixed with S2-Delta or S2-Serrate cells and the number of aggregates is quantified as described above. The relative decrease in the number of aggregates due to the presence of cis-ligands provides a measure of cis-ligand-mediated inhibition of trans-binding. These straightforward assays can provide semi-quantitative data on the effects of genetic or pharmacological manipulations on the binding of Notch to its ligands, and can help deciphering the molecular mechanisms underlying the in vivo effects of such manipulations on Notch signaling.

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Complexity of in vivo systems makes it difficult to distinguish between the activation and inhibition of Notch receptor by trans- and cis-ligands, respectively. Here, we present a protocol based on in vitro cell-aggregation assays for qualitative and semi-quantitative evaluation of the binding of Drosophila Notch to trans-ligands vs cis-ligands.

Notch signaling is an evolutionarily conserved cell-cell communication system used broadly in animal development and adult maintenance. Interaction of the ...

Minimally Invasive Embryo Transfer and Embryo Vitrification at the Optimal Embryo Stage in Rabbit Model

Assisted reproductive techniques (ARTs), such as in vitro embryo culture or embryo cryopreservation, affect natural development patterns with perinatal and postnatal consequences. To ensure the innocuousness of ART applications, studies in animal models are necessary. In addition, as a last step, embryo development studies require evaluation of their capacity to develop full-term healthy offspring. Here, embryo transfer to the uterus is indispensable to perform any ARTs-related experiment.
The rabbit has been used as a model organism to study mammalian reproduction for over a century. In addition to its phylogenetic proximity to the human species and its small size and low maintenance cost, it has important reproductive characteristics such as induced ovulation, a chronology of early embryonic development similar to humans and a short gestation that allow us to study the consequences of ART application easily. Moreover, ARTs (such as intracytoplasmic sperm injection, embryo culture, or cryopreservation) are applied with suitable efficiency in this species.
Using the laparoscopic embryo transfer technique and the cryopreservation protocol presented in this article, we describe 1) how to transfer embryos through an easy, minimally invasive technique and 2) an effective protocol for long-term storage of rabbit embryos to provide time-flexible logistical capacities and the ability to transport the sample. The outcomes obtained after transferring rabbit embryos at different developmental stages indicate that morula is the ideal stage for rabbit embryo recovery and transfer. Thus, an oviductal embryo transfer is required, justifying the surgical procedure. Furthermore, rabbit morulae are successfully vitrified and laparoscopically transferred, proving the effectiveness of the described techniques.

Assisted reproductive techniques (ARTs) are in continuous evaluation to improve outcomes and reduce the associated risks. This manuscript describes a minimally invasive embryo transfer procedure with an efficient cryopreservation protocol that allows the use of rabbits as an ideal animal model of human reproduction.

Assisted reproductive techniques (ARTs), such as in vitro embryo culture or embryo cryopreservation, affect natural development patterns with perinatal ...

Isolation, Culture, Characterization, and Differentiation of Human Muscle Progenitor Cells from the Skeletal Muscle Biopsy Procedure

The use of primary human tissue and cells is ideal for the investigation of biological and physiological processes such as the skeletal muscle regenerative process. There are recognized challenges to working with human primary adult stem cells, particularly human muscle progenitor cells (hMPCs) derived from skeletal muscle biopsies, including low cell yield from collected tissue and a large degree of donor heterogeneity of growth and death parameters among cultures. While incorporating heterogeneity into experimental design requires a larger sample size to detect significant effects, it also allows us to identify mechanisms that underlie variability in hMPC&#160;expansion capacity, and thus allows us to better understand heterogeneity in skeletal muscle regeneration. Novel mechanisms that distinguish the expansion capacity of cultures have the potential to lead to the development of therapies to improve skeletal muscle regeneration.

We present techniques for isolating, culturing, characterizing, and differentiating human primary muscle progenitor cells (hMPCs) obtained from skeletal muscle biopsy tissue. hMPCs obtained and characterized through these methods can be used to subsequently address research questions related to human myogenesis and skeletal muscle regeneration.

The use of primary human tissue and cells is ideal for the investigation of biological and physiological processes such as the skeletal muscle ...

Human Egg Maturity Assessment and Its Clinical Application

The optimal timing of intracytoplasmic sperm injection (ICSI) is of a serious concern for fertility programs because untimely sperm entry diminishes the egg&#39;s developmental competence. Presence of the first polar body (PB) together with the meiotic spindle indicates completion of the oocyte maturation and the egg&#39;s readiness for fertilization. In clinical practice, it is customary to assume that all oocytes displaying a PB are mature metaphase (MII) oocytes. However, PB extrusion precedes the formation of the bipolar MII spindle. This asynchrony makes the mere presence of PB an unreliable marker of oocyte maturity. Noninvasive spindle imaging using polarized light microscopy (PLM) allows quick and easy inspection of whether the PB-displaying oocyte actually reassembled a meiotic spindle prior to ICSI. Here, we present a standard protocol to perform human egg maturity assessment in the clinical laboratory. We also show how to optimize the time of ICSI with respect to the oocyte&#39;s developmental stage in order to prevent premature sperm injection of late-maturing oocytes. Using this approach, even immature oocytes extruding PB in vitro can be clinically utilized. Affirmation that MII spindle is present prior to sperm injection and individual adjustment of the time of ICSI is particularly important in poor prognosis in-vitro fertilization (IVF) cycles with a low number of oocytes available for fertilization.

We provide an outline of the clinical protocol for non-invasive assessment of human egg maturity using polarized light microscopy.

The optimal timing of intracytoplasmic sperm injection (ICSI) is of a serious concern for fertility programs because untimely sperm entry diminishes the ...

Generation of Multicellular Human Primary Endometrial Organoids

The human endometrium is one of the most hormonally responsive tissues in the body and is essential for the establishment of pregnancy. This tissue can also become diseased and cause morbidity and even death. Model systems to study human endometrial biology have been limited to in vitro culture systems of single cell types. In addition, the epithelial cells, one of the major cell types of the endometrium, do not propagate well or retain their physiological traits in culture, and thus our understanding of endometrial biology remains limited. We have generated, for the first time, endometrial organoids that consist of both epithelial and stromal cells of the human endometrium. These organoids do not require any exogenous scaffold materials and specifically organize so that epithelial cells encompass the spheroid-like structure and become polarized with stromal cells in the center that produce and secrete collagen. Estrogen, progesterone and androgen receptors are expressed in the epithelial and stromal cells and treatment with physiological levels of estrogen and testosterone promote the organization of the organoids. This new model system can be used to study normal endometrial biology and disease in ways that were not possible before.

A protocol to generate human primary endometrial organoids that consist of epithelial and stromal cells and retain characteristics of the native endometrial tissue is presented. This protocol describes methods from uterine tissue acquisition to the histologic processing of endometrial organoids.

The human endometrium is one of the most hormonally responsive tissues in the body and is essential for the establishment of pregnancy. This tissue can ...

Minimum Volume Vitrification of Immature Feline Oocytes

In wild animals&#8217; conservation programs, gamete banking is crucial to safeguard genetic resources of valuable individuals and rare species and to promote biodiversity preservation. In felids, most species are threatened with extinction, and domestic breeds are used as a model to increase the efficiency of protocols for germplasm banking. Among oocyte cryopreservation techniques, vitrification is more and more popular in human and veterinary assisted reproduction. Cryotop vitrification, which was at first developed for human oocytes and embryos, has demonstrated to be well-suited for cat oocytes. This method offers several advantages, such as the feasibility in field conditions and the speed of the procedure, which can be helpful when several samples need to be processed. However, the efficiency is strongly dependent on the operator&#8217;s skills, and intra- and inter-laboratory standardization are needed, as well as personnel training. This protocol describes minimum volume vitrification of immature feline oocytes on a commercial support in a step by step field-friendly protocol, from oocyte collection to warming. Following the protocol, preservation of oocyte integrity and viability at warming (as high as 90%) can be expected, although there is still room for improvement in post-warming maturation and embryonic development outcomes.

This manuscript describes a protocol for the minimum volume vitrification of immature cat oocytes with laboratory-made media on commercial supports. It covers every step from oocyte isolation from ex vivo gonads to vitrification and warming.

In wild animals&#8217; conservation programs, gamete banking is crucial to safeguard genetic resources of valuable individuals and rare species and to ...