Elke Heytens

Reduced amounts and abnormal forms of phospholipase C zeta (PLCzeta) in spermatozoa from infertile men.

BACKGROUND In mammals, oocyte activation at fertilization is thought to be induced by the sperm-specific phospholipase C zeta (PLCzeta). However, it still remains to be conclusively shown that PLCzeta is the endogenous agent of oocyte activation. Some types of human infertility appear to be caused by failure of the sperm to activate and this may be due to specific defects in PLCzeta. METHODS AND RESULTS Immunofluorescence studies showed PLCzeta to be localized in the equatorial region of sperm from fertile men, but sperm deficient in oocyte activation exhibited no specific signal in this same region. Immunoblot analysis revealed reduced amounts of PLCzeta in sperm from infertile men, and in some cases, the presence of an abnormally low molecular weight form of PLCzeta. In one non-globozoospermic case, DNA analysis identified a point mutation in the PLCzeta gene that leads to a significant amino acid change in the catalytic region of the protein. Structural modelling suggested that this defect may have important effects upon the structure and function of the PLCzeta protein. cRNA corresponding to mutant PLCzeta failed to induce calcium oscillations when microinjected into mouse oocytes. Injection of infertile human sperm into mouse oocytes failed to activate the oocyte or trigger calcium oscillations. Injection of such infertile sperm followed by two calcium pulses, induced by assisted oocyte activation, activated the oocytes without inducing the typical pattern of calcium oscillations. CONCLUSIONS Our findings illustrate the importance of PLCzeta during fertilization and suggest that mutant forms of PLCzeta may underlie certain types of human male infertility.

Value of Early Referral to Fertility Preservation in Young Women With Breast Cancer

PURPOSE To determine whether early referral to reproductive specialists improves fertility preservation (FP) outcomes and reduces delay in adjuvant treatment in young women with breast cancer. PATIENTS AND METHODS A secondary analysis of a prospective database of patients with breast cancer undergoing ovarian stimulation (OS) for FP by oocyte or embryo cryopreservation was performed. RESULTS Of the 154 patients, 93 met the inclusion criteria (mean age, 35.2 ± 4.4 years). Thirty-five of the 93 patients were referred before breast surgery (PreS), and 58 patients were referred after surgery (PostS). The time periods from initial diagnosis (ID) to initiation of OS (42.6 ± 27.7 days for PreS v 71.9 ± 30.7 days for PostS; P < .001) and from ID to initiation of chemotherapy (83.9 ± 24.3 days for PreS v 107.8 ± 42.9 days for PostS; P = .045) were significantly shorter for the PreS group versus the PostS group. Nine (25.7%) of 35 patients in the PreS group versus one (1.7%) of 58 patients in the PostS group were able to undergo two FP cycles (P < .001), resulting in an increased yield of oocytes in the PreS group (18.2% [93 of 511 oocytes] v 0.6% [five of 800 oocytes], respectively; P < .001) and embryos (17.2% [40 of 233 embryos] v 0.6% [two of 357 embryos], respectively; P < .001). Patients who had an oocyte retrieval within 5 weeks of the surgery were able to complete a second cycle within 9 weeks of the surgery. CONCLUSION FP referral before breast surgery enables earlier initiation of cryopreservation cycles and chemotherapy and, when appropriate, multiple FP cycles. Women who can undergo multiple cycles may be at advantage for FP because of a larger number of oocytes or embryos cryopreserved. This is the first study demonstrating the benefit of early FP referral in patients with cancer.

Enhancement of Neoangiogenesis and Follicle Survival by Sphingosine-1-Phosphate in Human Ovarian Tissue Xenotransplants

Ovarian transplantation is one of the key approaches to restoring fertility in women who became menopausal as a result of cancer treatments. A major limitation of human ovarian transplants is massive follicular loss during revascularization. Here we investigated whether sphingosine-1-phosphate or its receptor agonists could enhance neoangiogenesis and follicle survival in ovarian transplants in a xenograft model. Human ovarian tissue xenografts in severe-combined-immunodeficient mice were treated with sphingosine-1-phosphate, its analogs, or vehicle for 1–10 days. We found that sphingosine-1-phosphate treatment increased vascular density in ovarian transplants significantly whereas FTY720 and SEW2871 had the opposite effect. In addition, sphingosine-1-phosphate accelerated the angiogenic process compared to vehicle-treated controls. Furthermore, sphingosine-1-phosphate treatment was associated with a significant proliferation of ovarian stromal cell as well as reduced necrosis and tissue hypoxia compared to the vehicle-treated controls. This resulted in a significantly lower percentage of apoptotic follicles in sphingosine-1-phosphate-treated transplants. We conclude that while sphingosine-1-phosphate promotes neoangiogenesis in ovarian transplants and reduces ischemic reperfusion injury, sphingosine-1-phosphate receptor agonists appear to functionally antagonize this process. Sphingosine-1-phosphate holds great promise to clinically enhance the survival and longevity of human autologous ovarian transplants.

Determinants of access to fertility preservation in women with breast cancer

OBJECTIVE To evaluate socioeconomic, demographic, and medical factors that influence the referral pattern-either before cancer treatment for fertility preservation (FP, early referral) or post-chemotherapy for assisted reproductive technology (PCART, delayed referral)-in women with breast cancer. DESIGN Secondary analysis. SETTING Academic medical centers. PATIENT(S) Three hundred fourteen patients with breast cancer who were counseled for FP (n=218) or PCART (n=96) from June 1999 to July 2009. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Factors favoring early referrals. RESULT(S) Mean age at diagnosis was higher in FP vs. PCART (35.3±4.5 years vs. 33.9±4.7 years). Ninety percent presented with cancer stage 1 or 2. From 2000 to 2009 the proportion of referrals for FP increased continually. In 2009, nearly all (95.5%) were for FP. The majority (63.8%) was referred from an academic center. Patients with a family history of breast cancer were more likely to consult for FP (75.2% vs. 64.3% without). There was no association with occupation, income, race, ethnicity, obstetric history, and prior infertility treatment. Only 22.9% of those counseled in PCART, compared with 45.0% in the FP group, proceeded with a procedure. CONCLUSION(S) There has been an increasing trend within the last 10 years for early referral of breast cancer patients to FP. Factors favoring early referrals are older age, early-stage cancer, family history of breast cancer, and academic center involvement. Those seen before cancer treatment are more likely to receive an intervention.

Xenotransplantation of cryopreserved human ovarian tissue into murine back muscle

BACKGROUND Ovarian tissue (OT) cryopreservation and transplantation are options for fertility preservation in young female cancer patients. METHODS We investigated xenotransplantation of human OT into back muscle (B) of severe combined immunodeficiency mice. OT follicle content was evaluated by stereomicroscopy and pre-transplantation. Xenograft survival, follicular development (with/without FSH administration), apoptosis and vascularization were compared in B- versus K-site (under the kidney capsule) several times after grafting using histology, immunohistochemistry and magnetic resonance imaging. In vitro maturation (IVM) was also performed. RESULTS Anastomoses which developed from existing human and invading murine vessels were seen in OT at both sites, but angiogenesis was more prominent at the B- than K-site (P < 0.001). Vascularization and follicle size were correlated in the B-group (Spearmans coefficient 0.73; P < 0.001). FSH increased early (8 days) micro-vessel formation in B but not in K grafts (P < 0.0001, versus no FSH). B-site grafts showed a better histological morphology and survival (P = 0.0084), formation of larger antral follicles (P = 0.005), more metaphase-II (MII) oocytes, growing follicles (P = 0.028) and slightly fewer apoptotic follicles than K grafts. One MI oocyte from B underwent IVM and reached MII stage next day. CONCLUSIONS To our knowledge, this is the first report of MII and IVM-MII oocytes obtained from B xenografts. We report the largest oval-shaped antral follicles containing an MII oocyte obtained after OT xenotransplantation to date. Xenografting in the mouse B should be further explored as a method for human OT transplantation.

Back muscle as a promising site for ovarian tissue transplantation, an animal model

BACKGROUND The aim of this study was to evaluate the optimal transplantation site for ovarian tissue fragments in murine hosts. We compared the transplantation to the back muscle (B) versus the kidney capsule (K) in a mouse allograft model. METHODS Hemi-ovaries from 12-day-old mice were allografted into B and K of bilaterally ovariectomized same strain recipients which had undergone gonadotrophin stimulation (n = 15). Graft survival after 27 days, angiogenesis and follicle development were scored and compared to age-matched control ovaries (38-day old, n = 5). The ability of oocytes to be fertilized was studied after IVF, ICSI and embryos were transferred to recipient mothers. Anti-mouse CD 31+ antibody was used to evaluate neo-vascularization in grafts. RESULTS Primordial follicle survival was higher (P < 0.01) and vascular support was better (P < 0.01) in B- than in K-grafts. From 34 oocytes retrieved from B-grafts (15 metaphase I, of which 14 matured in vitro, and 19 collected at metaphase II), 18 morulae were obtained. Transfer of 12 embryos obtained by ICSI led to three live offspring, and transfer of six IVF embryos to another recipient mother yielded four offspring, one of which was born dead and one showed placental anomalies. CONCLUSIONS The back muscle is a promising site for ovarian allografts in mice. This is the first report of live offspring obtained after back muscle grafting using both IVF and ICSI.

Reduced fertilization after ICSI and abnormal phospholipase C zeta presence in spermatozoa from the wobbler mouse

Failed fertilization after intracytoplasmic sperm injection (ICSI) can be due to a reduced oocyte-activation capacity caused by reduced concentrations and abnormal localization of the oocyte-activation factor phospholipase C (PLC) zeta. Patients with this condition can be helped to conceive by artificial activation of oocytes after ICSI with calcium ionophore (assisted oocyte activation; AOA). However some concern still exists about this approach. Mouse models could help to identify potential oocyte-activation strategies and evaluate their safety. In this study, the fertilizing capacity of wobbler sperm cells was tested and the efficiency of AOA with two exposures to ionomycin to restore fertilization and embryo development was studied. The quality of the obtained blastocysts was assessed and embryo transfer was performed to evaluate post-implantation development. The presence of PLCzeta in the spermatozoa and testis of the wobbler mouse was evaluated by PLCzeta immunostaining and quantitative reverse-transcription polymerase chain reaction. Sperm cells from wobbler mice had reduced fertilizing capacity and abnormalities in PLCzeta localization, but not in its expression. Artificially activating the oocytes restored fertilization and embryo development. Therefore, the wobbler mouse can be a model for failed fertilization after ICSI to study PLCzeta dynamics and aid in optimization of the AOA method.

Effect of ionomycin on oocyte activation and embryo development in mouse

Artificial oocyte activation using the calcium ionophore ionomycin is applied successfully in assisted reproduction but some concern exists on the clinical use. The aims of the present study were to optimize the oocyte activation scheme and to address embryo toxicity in a mouse model. Efficiency of oocyte activation and subsequent development was evaluated and ionomycin was found to be an efficient activator at 10 micromol/l. An improved effect of a second exposure to 5 micromol/l ionomycin on blastocyst development was observed. Toxicity of ionomycin on embryos was then investigated by evaluating pre- and post-implantation development of in-vivo fertilized oocytes following exposure to ionomycin. Blastocyst development, blastocyst cell numbers in trophectoderm and inner cell mass were not different between treated and non-treated zygotes. Also implantation rates and fetal parameters such as length, weight and morphological parameters were similar between the fetuses originating from zygotes treated with ionomycin and non-treated zygotes. Furthermore, healthy offspring originating from ionomycin-treated zygotes was born. In conclusion, no adverse effects of ionomycin on in-vitro or in-vivo mouse embryo development were noticed, giving arguments in favour of the use of ionomycin, although negative long-term effects of this compound cannot be excluded at present.

Value of early referral to improve fertility preservation outcomes in women with breast cancer.

9026 Background: ASCO recommends that young cancer patients be referred to specialists for fertility preservation (FP) as soon as possible after the diagnosis, however, there is no data to directly...