Rôle des protéases et de leurs inhibiteurs dans la placentation et la vascularisation endométriale

Le rôle important joué par les protéases dans plusieurs processus physiologiques (reproduction, cicatrisation et régénération tissulaire) n’exclut pas leurs contributions parfois primordiales dans divers pathologies, telles que la croissance tumorale et les métrorragies dysfonctionnelles. Lors de ce travail, nous nous sommes intéressés à l’étude des protéases et de l’angiogenèse au niveau de deux aspects distincts de la reproduction :1)Une situation physiologique qu’est la placentation par le biais d’un modèle murin ;2)Une situation pathologique chez les femmes souffrant de métrorragies dysfonctionnelles suite à l’utilisation d’un système intra-utérin à libération de progestatif comme moyen de contraceptio

Preservation of female fertility: The current therapeutic strategy.

peer reviewedBACKGROUND: Preservation of female fertility is a relatively new field in medicine that has grown very rapidly in recent decades. At the beginning, embryo freezing remained the most effective technique. Thereafter, cryopreservation of oocytes and ovarian tissue was considered a secure tool in human fertility preservation. Storage of cortical ovarian tissue is moreover relevant for children, prepubertal girls, and adult patients who cannot benefit from cryopreservation of oocytes. OBJECTIVE: To analyze and review recent and relevant scientific literature on medical and social reasons for preservation of fertility. METHODS: The review was conducted based on articles identified from PubMed databases using keywords. MAIN RESULTS: Oocyte vitrification allows women to preserve their fertility without the need for fertilization. Nowadays, thousands of healthy children have been born from this procedure. Occurrence of pregnancy depends on two main factors: the number of mature oocytes in storage and the age of the patient at the time of vitrification. Numerous adaptations have been developed to suit the ovarian stimulation regiments to patients with cancer. In young prepubertal girls, freezing of ovarian tissue remains the best and only option. CONCLUSION: Oocyte vitrification therefore appears to be the gold standard technique of preserving fertility in young women

Differential elevation of matrix metalloproteinase expression in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time

peer reviewedBACKGROUND: The levonorgestrel-releasing intrauterine system (LNG-IUS) is an effective contraceptive and has many non-contraceptive health benefits. However, it is commonly associated with irregular endometrial bleeding. Metalloproteinases contribute to extracellular matrix (ECM) remodelling and regulate bleeding during the menstrual cycle. Enhanced metalloproteinase expression participates in the pathogenesis of breakthrough bleeding. Thus the objective of this study was to compare matrix metalloproteinase (MMP) expression in endometrium during luteal phase and in short-term (1 month) and long-term (> or =6 months) LNG-IUS users. METHODS: MMP expression was analysed by semi-quantitative RT-PCR and immunohistochemistry. Gelatinase activity was determined by gelatin zymography. RESULTS: MMP-1, -2, -3, -7, -9 and -12 mRNAs levels were increased, whereas that of MMP-26 was decreased in the endometrium of LNG-IUS users. MMP-1, -2, -3, -7 and -9 were localized by immunohistochemistry in all biopsies in the short-term group but in only 0-27% in the control group. The incidence of positive immunostaining for MMP-2 and -3 decreased significantly in the long-term compared with short-term LNG-IUS users. MMP-26 was localized in all biopsies from the control group but in only 14 and 25% from the short- and long-term LNG-IUS groups, respectively. In both LNG groups, the numbers of macrophages (the major source of MMP-12) was increased. CONCLUSIONS: MMP-1, active MMP-2, MMP-3, MMP-7, MMP-9 and MMP-12 are more prevalent in the short-term LNG-IUS group, suggesting their important contribution to ECM breakdown and transient bleeding. The decrease in the percentage of women expressing MMP-2 and -3 might contribute to the decreased occurrence of unwanted spotting and bleeding in long-term LNG-IUS users

Influence of mouse strain on ovarian tissue recovery after engraftment with angiogenic factor.

BACKGROUND: For women facing gonadotoxic treatment, cryopreservation of ovarian tissue with subsequent retransplantation during remission is a promising technique for fertility preservation. However, follicle loss within grafted ovarian tissue can be caused by ischemia and progressive revascularization. Several xenograft models using different immunodeficient rodent lines are suitable for studying ovarian tissue survival and follicular viability after frozen-thawed ovarian cortex transplantation. SCID mice, which are deficient for functional B and T cells, are the most commonly used mice for ovarian xenograft studies. However, due to incomplete immunosuppression, NOD-SCID mice displaying low NK cell function and an absence of circulating complement might be more appropriate. The present study aims to define the most appropriate immunodeficient mouse strain for ovarian tissue xenotransplantation by comparing ovarian graft recovery in SCID and NOD-SCID mice following engraftment in the presence of isoform 111 of vascular endothelial growth factor. METHODS: Sheep ovarian cortex fragments were embedded in a collagen matrix, with or without VEGF111, before being stitched onto the ovaries of SCID and NOD-SCID mice. Transplants were recovered after 3 days to study early revascularization or after 3 weeks to evaluate follicle preservation and tissue fibrosis through histological analyses. RESULTS: At day 3, vessels were largely reorganized in the ovarian grafts of both mouse strains. After 3 weeks, the cortical tissue was clearly identifiable in SCID mice but not in NOD-SCID mice. Upon VEGF111 treatment, vascularization was significantly improved 3 days after transplantation in SCID mice. This increase in vessel density was correlated with better follicular preservation in SCID mice 3 weeks after transplantation. Fibrosis was not decreased by VEGF treatment in either mouse strain. CONCLUSIONS: Tissue architecture and follicular morphology were better preserved in ovarian tissues grafted in SCID mice in comparison with NOD-SCID mice. Moreover, tissue revascularization was improved in SCID mice by VEGF111 graft treatment. Thus, we consider SCID mice to be the best murine model for studying ovarian tissue xenografts

Oocyte Cryopreservation in Patients with Endometriosis: Current Knowledge and Number Needed to Treat.

peer reviewedThe rise of oocytes cryopreservation (OOC) in assisted reproductive techniques allows fertility preservation (FP) in an increasing number of indications. Endometriosis, a highly prevalent disease, potentially impairing ovarian reserve, seems, therefore, an interesting indication for it. The purpose of this study is to summarize the available evidence concerning FP by OOC in women with endometriosis and to calculate the number needed to treat (NNT). In total, 272 articles related to this topic were identified in PubMed. Eight studies were eligible for the review. In order to shed some light, a SWOT analysis was performed and the argument pros and cons were developed. The NNT calculated of OOC was 16, meaning that 16 women need to perform an OOC for one of them to have a child that she would not have had without this technique. In conclusion, OOC must be discussed with patients who suffer from endometriosis since it is an effective technique of FP, which can allow these patients to succeed a pregnancy that they otherwise would not have achieved. Nevertheless, it should not be performed in all patients as there is still a lack of robust socio-economic and risk-benefit data

Cancer and the right to motherhood

peer reviewe

Endometrial vessel maturation in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time

BACKGROUND: Levonorgestrel-releasing intrauterine system (LNG-IUS), although inserted to reduce heavy menstruation, causes irregular early transient bleeding. The objective of the study was to document quantitative changes in endometrial vessels of short- ( or =12 months) LNG users. The area, density and maturation of endometrial vessels were quantified in 19 endometrial biopsies of women with LNG-IUS and in 10 normally ovulating patients during mid-luteal phase. METHODS: Vessel maturation was evaluated by double immunostaining using anti-von Willebrand factor (endothelial cell marker) and anti-alpha Smooth Muscle Actin (vascular smooth muscle cells) antibodies. Vessel area, number and density were quantified with a novel computer-assisted image analysis system. RESULTS: Endometrium exposed to LNG-IUS for 1-3 months displayed a 11.5-fold increase in small naked vessel number. The partially mature vessel (alphaSMA partially positive) number increased six times. After long-term LNG-IUS treatment, the immature and partially mature vessel number remained four times higher than in the control group. Vessel area and density also increased dramatically in a time-dependent pattern with LNG-IUS use. CONCLUSIONS: Levonorgestrel affects blood vessel number, area, density and maturation in a time-dependent pattern that may explain the early transient increase in breakthrough bleeding with the LNG-IUS

Transient reduction of placental angiogenesis in PAI-1 deficient mice

Murine placentation is associated with the invasion of maternal endometrium by trophoblasts and an extensive maternal and foetal angiogenesis. Plasminogen activator inhibitor-1 (PAI-1) is transiently produced by spongiotrophoblasts and trophoblast giant cells at 10.5-11.5 day post-coitum (dpc). Knowing the key contribution of PAI-1 in the regulation of angiogenesis, we have now analyzed the consequence of PAI-1 deficiency on murine placentation. Morphological and quantitative computer-assisted image analysis revealed abnormal placental morphology in PAI-1 (-/-) mice at 10.5 and 12.5 dpc. At 10.5 dpc, the genetic ablation of PAI-1 resulted in a transient reduction of both maternal and foetal vascularizations in the placenta and increased trophoblast cell density. This was associated with a poorer development of the labyrinth and an extension of the decidua. A larger spongiotrophoblast layer appeared at 12.5 dpc in PAI-1 deficient mice. Placental morphology was normalized at 14,5 dpc. Microarray analyses performed on laser capture microdissected labyrinths revealed that 46 genes were differentially expressed at 10.5 dpc between the two genotypes. However, only 11 genes were still differently modulated at 14.5 dpc when normalization of placental morphology had take place. This transcriptomic profiling highlighted a dysregulation in the expression of placenta-related cathepsin family members. All together our data provide evidence for a transient impaired placental morphology in PAI-1-deficient mice which is then normalized leading to normal embryonic development

Isoform 165 of vascular endothelial growth factor in collagen matrix improves ovine cryopreserved ovarian tissue revascularisation after xenotransplantation in mice.

BACKGROUND: Aggressive anti-cancer treatments can result in ovarian failure. Ovarian cryopreservation has been developed to preserve the fertility of young women, but early graft revascularisation still requires improvement. METHODS: Frozen/thawed sheep ovarian cortical biopsies were embedded in collagen matrix with or without isoform 165 of vascular endothelial growth factor (VEGF165) and transplanted into ovaries of immunodeficient mice. Ovaries were chosen as transplantation sites to more closely resemble clinical conditions in which orthotopic transplantation has previously allowed several spontaneous pregnancies. RESULTS: We found that VEGF165 significantly increased the number of Dextran-FITC positive functional vessels 3 days after grafting. Dextran- fluorescein isothiocyanate (FITC) positive vessels were detectable in 53% and 29% of the mice in the VEGF-treated and control groups, respectively. Among these positive fragments, 50% in the treated group displayed mature smooth-muscle-actin-alpha (alpha-SMA) positive functional vessels compared with 0% in the control group. CD31 positive murine blood vessels were observed in 40% of the VEGF165 transplants compared with 21% of the controls. After 3 weeks, the density of murine vessels was significantly higher in the VEGF165 group. CONCLUSION: The encapsulation of ovarian tissue in collagen matrix in the presence of VEGF165 before grafting has a positive effect on functional blood vessel recruitment. It can be considered as a useful technique to be improved and further developed before human clinical applications in female cancer patients in the context of fertility preservation