Laurie Henry

Isoform 111 of vascular endothelial growth factor (VEGF111) improves angiogenesis of ovarian tissue xenotransplantation

Background Cryopreservation of cortex ovarian tissue before anticancer therapy is a promising technique for fertility preservation mainly in children and young women. Ischemia in the early stage after ovarian graft causes massive follicle loss by apoptosis. VEGF111 is a recently described vascular endothelial growth factor (VEGF) isoform that does not bind to the extracellular matrix, diffuses extensively, and is resistant to proteolysis. These properties confer a significantly higher angiogenic potential to VEGF111 in comparison with the other VEGF isoforms. Methods We evaluated the morphology of cryopreserved sheep ovarian cortex grafted in the presence or absence of VEGF111. Ovarian cortex biopsies were embedded in type I collagen with or without VEGF111 addition before transplantation to severe combined immunodeficient mice ovaries. Transplants were retrieved 3 days or 3 weeks later. Follicular density, vasculature network, hemoglobin content, and cell proliferation were analyzed. Results Addition of VEGF111 increased density of functional capillaries (P=0.01) 3 days after grafting. By double immunostaining of Ki-67 and von Willebrand factor, we demonstrated that proliferating endothelial cells were found in 83% of the VEGF111 group compared with 33% in the control group (P=0.001). This angiostimulation was associated with a significant enhancement of hemoglobin content (P=0.03). Three weeks after transplantation, the number of primary follicles was significantly higher in VEGF111 grafts (P=0.02). Conclusion VEGF111 accelerates blood vessel recruitment and functional angiogenesis and improves the viability of ovarian cortex by limiting ischemia and ovarian cortex damage.

Strategies for using the sheep ovarian cortex as a model in reproductive medicine.

Objective To evaluate and compare the distribution and density of primordial follicles within a whole sheep ovary and to gain insight into how to overcome the impact of natural follicular heterogeneity on the experimental results. Design Histological study. Setting Academic research center. Animals Five- to nine-month-old ewes. Interventions Freshly sampled whole sheep ovaries were collected and prepared for histological analysis. Main Outcome Measure(s) The follicular densities and distributions were determined for hematoxylin and eosin sections. A mathematical model was derived based on the follicle counts and Monte-Carlo simulations. Results Heterogeneous distributions and densities of primordial follicles were identified 1) for distinct areas of the same ovarian cortex, 2) between the ovaries of the same animal and 3) across different ewes. A mathematical model based on the analysis of 37,153 primordial follicles from 8 different ovaries facilitated the estimation of the number of cortical biopsies and sections that had to be analyzed to overcome such heterogeneity. Conclusion The influence of physiological follicular heterogeneity on experimental and clinical results can be overcome when a definite number of cortical pieces and sections are taken into consideration.

Comparison between paraffin and mineral oil covering on early human embryo culture: a prospective randomized study

ABSTRACT The oil overlay in microdrop culture systems prevents medium evaporation, helps to maintain appropriate pH and osmotic conditions and protects from microbial contamination. In the present study, we prospectively compared covering by Ovoil™, a paraffin oil, and LiteOil®, a mineral oil, on the in vitro development of human embryos and their suitability for transfer/freezing at day 3 and live birth rate. One hundred and one patients undergoing in vitro fertilization (IVF) treatment by intracytoplasmic sperm injection (ICSI) were enrolled in our study. After ICSI, 1237 oocytes were 1:1 randomly allocated into 2 groups according to the type of overlaying oil: Ovoil™ (616 oocytes) or LiteOil® (621 oocytes). Fertilization rate was assessed around 18 hours post-insemination (hpi) and embryos were checked for early cleavage at 25 hpi. Embryo morphology was recorded on days 2 and 3. A total of 437 (Ovoil™) and 438 day 3 embryos (LiteOil®) were analyzed. There were no differences between the two groups in terms of fertilization rate and occurrence of early cleavage. The proportion of top quality embryos (41.7% vs. 41.2%) and the final utilization rates (92.2% vs. 92.0%) were similar in Ovoil and LiteOil groups, respectively, at day 3. Live birth rate per transfer was essentially the same with Ovoil™ overlay (26.9%) when compared to LiteOil® (26.2%). Live birth rate in patients who simultaneously received embryos from both overlay types was 17.2%. Despite the different characteristics of these two oils regarding hydrocarbon saturation, packing and temperature storage, Ovoil™ and LiteOil® can be used in parallel in the same IVF protocol. Abbreviations: ART: assisted reproductive technologies; hpi: hours post-insemination; hSA: human serum albumin; HTF: human tubal fluid; ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; MII: metaphase II; MEA: mouse embryo assay; RT: room temperature.