Effects of sperm insemination on the final meiotic maturation of mouse oocytes arrested at metaphase I after in vitro maturation / 대한생식의학회지

OBJECTIVE: The aims of this study were to investigate whether fertilization could induce the resumption of meiosis in mouse oocytes arrested at metaphase I (MI) after in vitro maturation (IVM), and to investigate the effect of Ca²⁺ chelator treatment at the time of fertilization on the transition from MI to metaphase II (MII). METHODS: MII-stage and arrested MI-stage mouse oocytes after IVM were fertilized, and then embryonic development was monitored. Blastocysts from each group were transferred into 2.5 days post-coitum pseudo-pregnant ICR mice. MI oocytes after IVM were treated with a Ca²⁺ chelator to investigate the effect of Ca²⁺ oscillations on their maturation. RESULTS: As insemination time increased, the number of oocytes in the MI group that reached the MII stage also increased. The blastocyst rates and total cell numbers in the MII group were significantly higher than in the MI group. No pregnancy occurred in the MI group, but 10 pregnancies were achieved (10 of 12) in the MII group. The proportion of MI oocytes that matured to MII oocytes after fertilization was significantly higher in the non-treated group than in the Ca²⁺ chelator-treated group. CONCLUSION: The findings that a higher proportion of MI-arrested oocytes progressed to MII after fertilization and that the MI-to-MII transition was blocked by Ca2+ chelator treatments before fertilization indicate that the maturation of MI oocytes to MII oocytes is associated with intracellular Ca²⁺ oscillations driven by fertilization.

Maduración in vitro de ovocitos con cultivo extendido hasta estadio de blastocisto: Primer nacimiento reportado en el Perú / In vitro oocyte maturation combined with extended blastocyst embryo culture: Report of the first baby born in Peru

La maduración in vitro de ovocitos (MIV) es una técnica de reproducción asistida muy poco difundida entre los centros de reproducción asistida, debido al bajo éxito en obtener embarazos. Sin embargo, en los últimos años, diferentes estrategias empleadas han demostrado tasas de embarazo similares a las técnicas convencionales de fecundación in vitro (FIV). En el presente reporte, describimos el caso clínico del primer nacido vivo usando MIV en combinación del cultivo extendido hasta estadio de blastocisto.

In vitro oocyte maturation is not yet considered a well-established technique in in vitro fertilization (IVF) laboratories. This is due to a lower pregnancy rates. However in the last few years, reports have shown similar pregnancy rates compared to the conventional IVF techniques. The current report describes the first baby born after an IVM treatment in combination with extended blastocyst culture in Peru.

Cryopreservation of in vitro matured oocytes after ex vivo oocyte retrieval from gynecologic cancer patients undergoing radical surgery / 대한생식의학회지

OBJECTIVE: The aim of this study was to report a case series of in vitro matured (IVM) oocyte freezing in gynecologic cancer patients undergoing radical surgery under time constraints as an option for fertility preservation (FP). METHODS: Case series report. University-based in vitro fertilization center. Six gynecologic cancer patients who were scheduled to undergo radical surgery the next day were referred for FP. The patients had endometrial (n=2), ovarian (n=3), and double primary endometrial and ovarian (n=1) cancer. Ex vivo retrieval of immature oocytes from macroscopically normal ovarian tissue was followed by mature oocyte freezing after IVM or embryo freezing with intracytoplasmic sperm injection. RESULTS: A total of 53 oocytes were retrieved from five patients, with a mean of 10.6 oocytes per patient. After IVM, a total of 36 mature oocytes were obtained, demonstrating a 67.9% maturation rate. With regard to the ovarian cancer patients, seven IVM oocytes were frozen from patient 3, who had stage IC cancer, whereas one IVM oocyte was frozen from patient 4, who had stage IV cancer despite being of a similar age. With regard to the endometrial cancer patients, 15 IVM oocytes from patient 1 were frozen. Five embryos were frozen after the fertilization of IVM oocytes from patient 6. CONCLUSION: Immature oocytes can be successfully retrieved ex vivo from macroscopically normal ovarian tissue before radical surgery. IVM oocyte freezing provides a possible FP option in patients with advanced-stage endometrial or ovarian cancer without the risk of cancer cell spillage or time delays.

The potential role of granulosa cells in the maturation rate of immature human oocytes and embryo development: A co-culture study / 대한생식의학회지

OBJECTIVE: In order to increase the number of mature oocytes usable for intracytoplasmic sperm injection (ICSI), we aimed to investigate the effect of co-culturing granulosa cells (GCs) on human oocyte maturation in vitro, the fertilization rate, and embryo development. METHODS: A total of 133 immature oocytes were retrieved and were randomly divided into two groups; oocytes that were cultured with GCs (group A) and oocytes that were cultured without GCs (group B). After in vitro maturation, only oocytes that displayed metaphase II (MII) underwent the ICSI procedure. The maturation and fertilization rates were analyzed, as well as the frequency of embryo development. RESULTS: The mean age of the patients, their basal levels of follicle-stimulating hormone, and the number of oocytes recovered from the patients were all comparable between the two study groups. The number of oocytes that reached MII (mature oocytes) was 59 out of 70 (84.28%) in group A, compared to 41 out of 63 (65.07%) in group B (p=0.011). No significant difference between fertilization rates was found between the two study groups (p=0.702). The embryo development rate was higher in group A (33/59, 75%) than in group B (12/41, 42.85%; p=0.006). The proportion of highest-quality embryos and the blastocyst formation rate were significantly lower in group B than in group A (p=0.003 and p<0.001, respectively). CONCLUSION: The findings of the current study demonstrate that culturing immature human oocytes with GCs prior to ICSI improves the maturation rate and the likelihood of embryo development.

Comparision of in vitro maturation applied in PCOS and non-PCOS patients undergo stimulated and unstimulated protocols / 中华妇产科杂志

Objective To compare the laboratory and clinical results between unstimulated in vitro maturation (IVM) and IVM converted from in vitro fertilization (IVF) in polycystic ovarian syndrome (PCOS) and non-PCOS patients.Methods We divided 591 IVM cycles in the First Affiliated Hospital of Wenzhou Medical Univesity from Jan.2008 to Dec.2013 into 4 groups:group A1B1,PCOS patients underwent unstimulated IVM protocol,240 cycles; group A1B2,PCOS patients underwent IVM converted from conventional stimulated IVF protocol,153 cycles; group A2B1,non-PCOS patients underwent unstimutlated IVM protocol,103 cycles; group A2B2,non-PCOS patient underwent IVM converted from conventional stimulated IVF protocol,95 cycles.Multiple linear regression method and binary logistic regression method were used to assess the influence of PCOS and protocols for IVM on laboratory and clinical outcomes.Results The mean number of oocytes retrieved was positively related with PCOS [partial regression coefficient (B)=3.37,P＜0.01].The maturation rate of oocytes was positively related with hCG-prime prior to oocyte aspiration (B=0.05,P=0.010).High-quality embryo rate was positively related with PCOS and IVM converted from IVF (B=0.08,P=0.010; B=0.09,P=0.001),as well as implantation rate related with them (B=0.07,P=0.010; B=0.10,P＜0.01).PCOS and IVM converted from IVF improved hCG positive (hCG＞10 U/L) rate (OR=1.636,95％CI:1.113-2.204,P＜0.05; OR=1.861,95％CI:1.307-2.649,P＜0.05) and the clinical pregnancy rate (OR=1.507,95％CI:1.041-2.240,P＜0.05; OR=1.881,95％CI:1.312-2.696,P＜0.05).IVM converted from IVF protocol decreased the spontaneous abortion rate (OR=0.490,95％CI:0.245-0.978,P＜0.05).Multiple gestation rate and ectopic pregnancy rate were not affected by PCOS condition and protocol used (P＞0.05).Conclusions PCOS and IVM converted from IVF protocol improved the high-quality embryo rate,implantation rate,hCG positive rate and clinical pregnancy rate.IVM converted from IVF protocol reduced the spontaneous abortion rate.PCOS patients may be more suitable for the IVM treatment.No matter PCOS or non-PCOS patients,IVM converted from IVF protocol had better pregnancy outcome than that of unstimulated cycle.

Preservação da fertilidade em mulheres com câncer: atualização e perspectivas / Fertility preservation in women with cancer: update and perspectives

Com o aumento do diagnóstico de câncer em mulheres jovens e os avanços no seu tratamento, muitas pacientes que poderão ter sua fertilidade comprometida com a quimioterapia têm manifestado desejo de engravidar futuramente. O congelamento de embriões, após fertilização in vitro, para preservar a fertilidade está bem estabelecido. A criopreservação de oócitos por vitrificação evoluiu bastante nos últimos anos, deixando de ser experimental. Até 2009 nasceram mais de 900 crianças a partir de oócitos criopreservados, sem aumento do risco de anomalias congênitas. O uso de análogos do GnRH para a supressão ovariana durante a quimioterapia na tentativa de prevenir a falência ovariana prematura apresenta resultados incertos. Outras técnicas ainda são consideradas experimentais, como a criopreservação e posterior autotransplante de tecido ovariano. Já foram relatados 24 nascimentos com o seu uso, persistindo, entretanto, dúvidas que motivam o seu estudo. A maturação de folículos ovarianos in vitro é alternativa promissora para preservação da fertilidade nessas pacientes e tem apresentado resultados positivos em roedores, macacos e humanos. Muita cautela deve ser tomada com o uso de técnicas experimentais, especialmente quando oferecidas para pacientes diante de fragilidade emocional. Por isso, é importante transmitir corretamente informações sobre chances de gravidez com tratamentos existentes e as limitações das técnicas experimentais...

With the increased number of cancer diagnoses among young women and the advances in treatment, many patients who may have had their fertility compromised by chemotherapy express desire to become pregnant in the future. Freezing embryos for later IVF so as to preserve fertility is a well established process. Oocyte cryopreservation by vitrification has evolved greatly in recent years and is no longer considered experimental. By 2009 more than 900 children were born from cryopreserved oocytes, without increased risk of congenital anomalies. The preventive use of GnRH analogues for ovarian suppression during chemotherapy to avoid premature ovarian failure has uncertain outcomes. Other techniques such as cryopreservation of ovarian tissue for later autograft are still considered experimental. Although use has already been reported in 24 births, doubts still persist and motivate further study. In vitro maturation of ovarian follicles is a promising alternative for preserving patient fertility and has shown positive results in rodents, monkeys, andhumans. Caution should be used with experimental techniques, especially when offered to emotionally fragile patients. Therefore it is important to thoroughly convey information on the chances of pregnancy with existing treatments and the limitations of experimental techniques...

Fertilization and pregnancy potential of immature oocytes from stimulated intracytoplasmic sperm injection cycles / 대한생식의학회지

OBJECTIVE: We evaluated the fertilization potential of immature oocytes obtained from controlled ovarian hyperstimulation cycles of patients undergoing ICSI. METHODS: We retrospectively analyzed 463 ICSI cycles containing at least one immature oocyte at oocyte denudation. ICSI was performed on mature oocytes at oocyte denudation (metaphase-II [MII] oocytes) and the oocytes that extruded the first polar body between oocyte denudation and ICSI (MI-MII oocytes). Fertilization and early embryonic development were compared between MII and MI-MII oocytes. To investigate the pregnancy potential of MI-MII oocytes, the pregnancy outcome was analyzed in 24 ICSI cycles containing only immature oocytes at retrieval. RESULTS: The fertilization rate of MI-MII oocytes (37.0%) was significantly lower than that of MII oocytes (72.3%). The rates of delayed embryos and damaged embryos did not significantly differ. Eighty-one immature oocytes were retrieved in 24 cycles that retrieved only immature oocytes and 61 (75.3%) of them were in the MI stage. ICSI was performed on 36 oocytes (59.0%) that extruded the first polar body before ICSI and nine MI-MII oocytes (25.0%) were fertilized. Embryo transfers were performed in five cycles. Pregnancy was observed in one cycle, but it ended in biochemical pregnancy. CONCLUSION: In ICSI cycles, oocytes that extruded the first polar body between denudation and ICSI can be used as a source of oocytes for sperm injection. However, their fertilization and pregnancy potential are lower than that of mature oocytes. Therefore, ovarian stimulation should be performed carefully for mature oocytes obtained at retrieval, especially in cycles with a small number of retrieved oocytes.

Oócitos aparentemente maduros injetados em telófase I apresentam piores resultados de reprodução assistida / Apparently matured oocytes injected in telophase I have worse outcomes from assisted reproduction

OBJETIVO: Avaliar o estágio de maturação nuclear de oócitos com o primeiro corpúsculo polar (CP) visível de pacientes inférteis submetidas à estimulação ovariana para injeção intracitoplasmática de espermatozoide (ICSI) e comparar os resultados da injeção intracitoplasmática de espermatozoide entre os oócitos em telófase I (TI) e metáfase II (MII), e entre aqueles em metáfase II com e sem fuso celular visível. MÉTODOS: Estudo prospectivo que incluiu 106 pacientes inférteis submetidas à injeção intracitoplasmática de espermatozoide. Foram incluídas pacientes com idade menor ou igual a 38 anos, hormônio folículo estimulante (FSH) basal menor que 10 mIU/mL e índice de massa corpórea (IMC) menor que 30 kg/m². Foram excluídas pacientes com doenças sistêmicas, com qualquer infecção ativa, tabagistas ou que fizeram uso de medicações hormonais e anti-inflamatórias hormonais e não hormonais nos últimos dois meses, previamente à programação para o procedimento de reprodução assistida. Os oócitos com extrusão do primeiro corpúsculo polar foram avaliados pela microscopia de polarização, imediatamente antes da realização da injeção intracitoplasmática de espermatozoide, e caracterizados quanto ao estágio de maturação nuclear (telófase I ou metáfase II). Os oócitos em metáfase II foram avaliados de acordo com a presença ou não do fuso meiótico. Foram analisadas as taxas de fertilização, clivagem e o número de embriões de boa qualidade no segundo dia (D2) de desenvolvimento. Os dados foram analisados comparativamente através do teste exato de Fisher. Em todas as análises foi considerado o nível de significância de 5% (p<0,05). RESULTADOS: O fuso meiótico de 516 oócitos foi visualizado através da microscopia de polarização. Dezessete dos 516 oócitos avaliados estavam em telófase I (3,3%) e 499 (96,7%) em metáfase II. Os oócitos injetados em telófase I apresentaram taxas de fertilização significativamente menores do que os injetados em metáfase II (53 e 78%, respectivamente) e não produziram nenhum embrião de boa qualidade no segundo dia. Comparando-se os oócitos com e sem fuso celular visível, não foi observada diferença significativa nos resultados de injeção intracitoplasmática de espermatozoide. CONCLUSÕES: Oócitos injetados em telófase I apresentaram menores taxas de fertilização quando comparados aos em metáfase II. É possível que a análise do estágio de maturação nuclear oocitária, por meio da microscopia de polarização, possa ser utilizada como fator de predição das taxas de fertilização pós-injeção intracitoplasmática de espermatozoide.

PURPOSE: To evaluate the nuclear maturation stage and the presence of meiotic spindles of in vivo matured oocytes from infertile women undergoing stimulated cycles for intracytoplasmic sperm injection (ICSI) and compare intracytoplasmic sperm injection outcomes between oocytes in telophase I (TI) and metaphase II (MII), and the ones with and without visible meiotic spindle. METHODS: A prospective and controlled study with 106 infertile patients who underwent ovarian stimulation for intracytoplasmic sperm injection purposes. Patients aged 38 years or less, with basal follicle stimulating hormone (FSH) less than 10 mIU/mL and body mass index (BMI) less than 30 kg/m². Were included patients presenting any systemic diseases, any active infection, smokers or patients who had been using hormonal medications and hormonal and nonhormonal anti-inflammatory drugs for the past two months prior to the assisted reproduction procedure were excluded. The oocytes with the first polar body extruded (in vivo matured oocytes) were imaged by polarization microscopy immediately before intracytoplasmic sperm injection and characterized according to nuclear maturation stage (telophase I and metaphase II) and to the presence of a meiotic spindle. We analyzed the fertilization rates, cleavage, number of good quality embryos on the second day (D2) from oocytes on telophase I versus those in metaphase II, and metaphase II visible spindle versus non-visible ones. Data were analyzed comparatively by Fisher's exact test. The level of significance was set at 5% in all analyses (p<0.05). RESULTS: The meiotic spindles of 516 oocytes were imaged using polarization microscopy. From the 516 oocytes analyzed, seventeen were in telophase I (3.3%) and 499 (96.7%) in metaphase II. The oocytes injected in telophase I had significantly lower fertilization rates than those injected in metaphase II (53 and 78%, respectively) and produced no good quality embryos on day 2. When the oocytes with and without a visible meiotic spindle were compared, there was no significant difference in the intracytoplasmic sperm injection results. CONCLUSIONS: Oocytes injected in telophase I showed lower fertilization rates when compared to those in metaphase II. It is possible that the analysis of oocyte nuclear maturation by polarization microscopy can be used as a predictor of fertilization after intracytoplasmic sperm injection.

Factors that affect the in vitro production of bovine embryos. A review / Factores que afectan la producción in vitro de embriones bovinos: una revisión / Fatores que afetam a produção in vitro de embriões bovinos. A revisão

In vitro embryo production (IVP) represents a way to increase gamete use from animals with high zootechnical value. In spite of the advances obtained in IVP over the last few years, production of transferable embryos is still low. The aim of this review is to discuss ways to produce in vitro embryos, as well as oocytes formation and maturation processes that can be related to the effectiveness of obtained results. Some studies show the influence of follicular growth factors, gonadotropins, steroids and other hormones on the follicular development and the quality of the cumulus oocyte complex (COC). The follicular phase of slow growth is critical for the development of the oocyte capacity to reach the final competence and diameter. Information about endocrine influences, or likewise, the dependence of growth of small antral follicles when a loss in the oocyte or follicle functionality occurs is scarce in the literature. A variable number of different techniques and protocols for treatment of oocytes donors are described with the aim of improve the results, the COCs recovering rate and the developmental competence in vitro of collected oocytes. From the considerations presented in this review, it is possible to verify the importance of better understanding the factors involved in the IVP process, with the aim of allow new alternatives to increase the results obtained in programs of animal assisted reproduction.

La producción in vitro de embriones (PIV) representa una manera de aumentar el uso de gametos de animales con alto valor zootécnico. A pesar de los avances obtenidos en PIV en los últimos años, la producción de embriones tranferibles sigue siendo baja. El objetivo de esta revisión es discutir maneras de producir embriones in vitro, así como los procesos de formación y de maduración de los oocitos que se pueden relacionar con la eficacia de los resultados obtenidos. Algunos estudios demuestran la influencia de los factores foliculares del crecimiento, gonadotrofinas, esteroides y otras hormonas en el desarrollo folicular y la calidad del complejo del cumulus oocito (CCO). La fase folicular del crecimiento lento es crítica para el desarrollo de la capacidad del oocito de alcanzar la capacidad y el diámetro final. Información sobre influencias endocrinas, o además, la dependencia del crecimiento de pequeños folículos antrales cuando ocurre una pérdida en la funcionalidad del oocito o del folículo, es escasa en la literatura. Un número variable de diversas técnicas y los protocolos para el tratamiento de oocitos de las donantes son descritos en esta revisión, con lo objetivo de mejorar los resultados, el índice de la recuperacion de CCOs y la capacidad de desarrollo in vitro de oocitos recogidos. De las consideraciones presentadas en esta revisión, es posible verificar la importancia de entender los factores implicados en el proceso de PIV, para permitir el desarrollo de nuevas alternativas que mejoren los resultados obtenidos en programas de la reproducción animal asistida.

A produção in vitro (PIV) de embriões representa uma maneira de incrementar o uso de gametas de animais de alto valor zootécnico. Apesar dos avanços obtidos na PIV nos últimos anos, a produção de embriões transferíveis ainda é baixa. O objetivo desta revisão é discutir maneiras de produzir embriões in vitro, assim como o processo de formação e maturação de oócitos, que pode estar relacionado a eficácia dos resultados obtidos. Aguns estudos demonstram a influência de fatores de crescimento, gonadotrofinas, esteróides e outros hormônios no desenvolvimento folicular e na qualidade do complexo cumulus oócito (CCO). A fase folicular de crescimento lento é critica para o desenvolvimento da capacidade do oócito de atingir a competência e o diâmetro finais. Informação sobre as influências endócrinas, ou seja, da dependência do crescimento de pequenos folículos antrais quando ocorre perda da funcionalidade do oócito ou folículo são escassas na literatura. Um número variável de diferentes técnicas e protocolos para o tratamento de doadoras de ovóctios são descritos com o objetivo de melhorar os resultados, a taxa de recuperação de CCOs e o desenvolvimento da competência in vitro dos oócitos coletados. Das considerações apresentadas nesta revisão é possível verificar a importância do conhecimento dos fatores envolvidos no processo de PIV, com o objetivo de possibilitar que novas alternativas incrementem os resultados obtidos em programas de reprodução animal assistida.