Effect of dalteparin sodium administration on IVF outcome in non-thrombophilic young women: a pilot study.

This study evaluated whether heparin administration could affect IVF outcome. A total of 172 women, aged <40years, without laboratory findings of thrombophilia and undergoing their first IVF cycle, were randomly allocated to treatment (n=86) and control (n=86) groups. Patients allocated to the treatment group received low-molecular-weight heparin dalteparin sodium 2500IU s.c. daily, in addition to routine luteal phase support, from oocyte retrieval up to the day of the pregnancy test or up to the ninth week of pregnancy in the cases of positive human chorionic gonadotrophin. From the day after the oocyte retrieval, all patients began standard supplementation with vaginal progesterone 200mg twice a day. At the sixth week of pregnancy, patients underwent an ultrasound scan to assess the number/viability of gestational sacs. Implantation rates were 15% and 12% in the dalteparin and control groups, respectively. The clinical pregnancy rates/embryo transfers were 26% (19/73) and 20% (16/80), in the dalteparin and control groups, respectively, with live birth rates/embryo transfer of 21% (15/73) and 16% (13/80). Despite the lack of statistical significance, the increase in pregnancies observed in the treatment group may be considered as an important clinical point in the optimization of IVF clinical outcome.

Biological meaning of ubiquitination and DNA fragmentation in human spermatozoa.

The ubiquitin-proteasome is an ubiquitous system mainly devoted to protein degradation. The presence of ubiquitinated proteins in male gametes suggests a role for this system also in reproduction. Available evidence indicate that ubiquitin in spermatozoa may have a role in semen quality control, as ubiquitinated defective spermatozoa in the epididymis are subsequently phagocytosed by epididymal epithelial cells. Moreover, a role both in the regulation of mitochondrial inheritance in mammals (paternal mitochondria are eliminated and their ubiquitination appears to be important for this process) and in sperm-oocyte interaction at fertilization (which is inhibited by an inhibitor of proteasome) have been also suggested. We found that both morphologically normal and abnormal human spermatozoa in semen may be ubiquitinated and that the percentage of ubiquitinated sperm in the ejaculate positively correlates with normal morphology and motility, suggesting that sperm ubiquitination may have a positive role in sperm functions. It remains to be defined if and which patterns of ubiquitination of spermatozoa may distinguish between the different biological functions of this system. In an attempt to answer this question, we set up a method to detect simultaneously ubiquitination and DNA fragmentation by FACScan since the latter parameter is related to a poor quality of semen; in particular, abnormal morphology. We found that DNA fragmented human spermatozoa are also ubiquitinated. Studies are in progress to determine the correlation between the fraction of ubiquitinated-non DNA fragmented spermatozoa and parameters of semen analysis.

Lack of Histocompatibility Leukocyte Antigen-G expression in early embryos is not related to germinal defects or impairment of interleukin-10 production by embryos.

The expression of Histocompatibility Leukocyte Antigen (HLA)-G molecules is a mandatory prerequisite for the development of pregnancy but no hypotheses have yet been advanced regarding the lack of HLA-G modulation expression in a percentage of early embryos obtained by in vitro fertilization (IVF). One possible hypothetical model assumes that the absence of regulation of HLA-G or impaired interleukin (IL)-10 secretion could be related to germinal defects. We investigated the presence of soluble HLA-G antigens in supernatants of single embryo cultures from couples admitted to a second fertilization procedure; these couples showed a complete absence of HLA-G modulation in the first cycle's embryo supernatants (0/31). The results obtained in the second IVF cycle showed embryo supernatants positive for HLA-G (14/40), suggesting that the previous lack of antigen modulation is independent of germinal defects. Furthermore, since it has been reported that oocytes and early embryos can secrete IL-10, an anti-inflammatory cytokine produced by type 2 helper T cells that induces upregulation of HLA-G expression in monocytes and trophoblasts, we investigated the levels of IL-10 and soluble HLA-G in 40 embryo culture supernatants from 21 IVF cycles. No associations were observed between the presence of IL-10 and the production and concentrations of soluble HLA-G, or between IL-10 levels and pregnancy outcome. These results indicate that the lack of HLA-G production in early embryos is not related to germinal defects or to impairment in embryo IL-10 secretion but could be ascribed to possible uncorrected fertilization processes.

HLA-G expression in early embryos is a fundamental prerequisite for the obtainment of pregnancy.

Different mechanisms mediated by the expression of the HLA-class Ib HLA-G products are suggested to account for the induction of immune tolerance against the paternal antigens of the fetus during pregnancy. Soluble HLA-G antigens, mainly produced by cytotrophoblast cells at the materno-fetal interface and circulating in the body fluids, show a capacity analogous to that of membrane-boundstructures to inhibit NK cells. In the present report we have investigated, using specific ELISA, the presence of sHLA-G molecules in culture supernatants of early embryos obtained by in vitro fertilization (IVF) before transfer. The data obtained from the analysis of 285 supernatants corresponding to 101 IVF procedures (43 IVF, 58 intracytoplasmic sperm injection) identify two groups of patients on the basis of sHLA-G antigen presence. No differences in clinical parameters were observed between the groups, but positive embryo implantations occurred only in women showing sHLA-G molecules in culture supernatants (Fisher's exact p value 2.56 x 10(-3)). The results obtained indicate that expression of HLA-G products in embryo cells is a mandatory, but not sufficient, prerequisite for the development of pregnancy.