A membrane-based electrophoretic filtration system, known as the Cell Sorter-10 (CS-10), that preferentially isolates spermatozoa with very low levels of DNA damage has recently been developed. However, it remains to be proven whether spermatozoa prepared in this way are capable of achieving fertilization in assisted conception. Therefore, this clinical trial was designed to answer this question.

A split-sample split-cohort study design was employed to control for differences in semen and oocyte quality between 28 couples undergoing either intracytoplasmic sperm injection (ICSI) or IVF in this clinical trial. Each semen sample was split between preparation using the CS-10 and preparation by standard density gradient centrifugation (DGC) and each cohort of oocytes was split for insemination using either CS-10 (n = 197) or DGC (n = 195) prepared spermatozoa.

Both methods of sperm preparation yielded comparable rates of sperm recovery, motility and DNA fragmentation. There was no significant difference between the ability of CS-10 and DGC prepared spermatozoa to produce fertilization (62.4% versus 63.6%), cleavage (99.0% versus 88.5%) and high-quality embryos (27.4% versus 26.1%).

This pilot study demonstrates that membrane-based electrophoresis is as effective as DGC in preparing sperm for IVF and ICSI, although it takes only a fraction of the time.

Protein tyrosine phosphorylation is one of the main processes associated with sperm activation. Although this process and its targets have been well characterized, only few tyrosine kinases have been identified so far and their roles in spermatozoa are still largely unknown. In this study, we report the presence and localization of Src kinase in ejaculated human spermatozoa and investigate its role in regulating the processes underlying sperm activation.

Specific anti-Src antibodies, against different epitopes of the protein, identified a single band of ~70 kDa relating to a protein which is mainly localized in the post-acrosomal region of the head, neck and midpiece. By immunoprecipitation and immunofluorescence techniques performed with antibodies against Src phosphorylated at Tyr416, which identifies the active kinase, we showed an increased phosphorylation during sperm capacitation. Blocking Src activity with SU6656 resulted in a significant reduction in the protein tyrosine phosphorylation. Moreover, this inhibitor also blocked the progesterone-induced acrosome reaction and interfered with the calcium response to progesterone evaluated in fura-2-loaded spermatozoa. No effect on sperm motility and hyperactivation resulted from incubation with SU6656.

We identified a novel Src isoform in human spermatozoa, which appears to be involved in regulating sperm capacitation, calcium fluxes, tyrosine phosphorylation and acrosome reaction.

Sperm DNA damage is common amongst infertile men and may adversely impact natural reproduction, IUI-assisted reproduction and to a lesser degree IVF pregnancy. The aim of this study was to examine the influence of sperm DNA damage on the risk of spontaneous pregnancy loss after IVF and ICSI.

We conducted a systematic review and meta-analysis of studies on sperm DNA damage and pregnancy loss after an IVF and/or ICSI pregnancy.

Two by two tables were constructed and odds ratios (ORs) were derived from 11 estimates of pregnancy loss (five IVF and six ICSI studies from seven reports). These 11 studies involved 1549 cycles of treatment (808 IVF and 741 ICSI cycles) with 640 pregnancies (345 IVF and 295 ICSI) and 122 pregnancy losses. The combined OR of 2.48 (95% CI 1.52, 4.04, P < 0.0001) indicates that sperm DNA damage is predictive of pregnancy loss after IVF and ICSI.

In conclusion, sperm DNA damage is associated with a significantly increased risk of pregnancy loss after IVF and ICSI. These data provide a clinical indication for the evaluation of sperm DNA damage prior to IVF or ICSI and a rationale for further investigating the association between sperm DNA damage and pregnancy loss.

The precise mechanisms in the materno-fetal dialogue still remain unclear. The aim of this study was to investigate the role of the chemokine CXCL12 and its receptor CXCR4 in the interaction of trophoblasts and decidual stromal cells (DSCs).

Expression of CXCL12/CXCR4 in trophoblasts and DSCs was detected by reverse transcription–polymerase chain reaction and immunochemical staining. The secretion of CXCL12 by trophoblasts was determined by enzyme-linked immunosorbent assay. The effects of CXCL12 on the biological functions of trophoblasts and DSCs were analyzed using a cell viability assay, matrigel invasion assay and zymography. Finally, a co-culture model was established to investigate the modulation of CXCL12/CXCR4 in the interaction of trophoblasts and DSCs.

CXCR4 was transcribed and translated by both human trophoblasts and DSCs. Human trophoblasts secreted CXCL12 spontaneously in vitro, but DSCs did not. CXCL12 induced an apparent increase in the invasiveness of trophoblasts (P < 0.01), and up-regulated matrix metalloproteinase (MMP) 9 and MMP2 activity of both trophoblasts and DSCs (both P < 0.01) in an autocrine and paracrine manner. The invasiveness and MMP9 and MMP2 activity of trophoblasts in co-culture with DSCs increased significantly (P < 0.01), and these could be inhibited by anti-CXCR4 neutralizing antibody.

CXCL12 secreted by human trophoblasts enhances the coordination between trophoblasts and DSCs, via the regulation of MMP9 and MMP2, which may improve the functional materno-fetal interface.

The efficiency of in vitro maturation (IVM) techniques is suboptimal compared with controlled ovarian stimulation combined with IVF cycles, and studies are needed to identify factors that predispose IVM cycles to success or failure. We compared the outcome of IVM cycles with different dominant follicle (DF) size at oocyte retrieval following hCG priming.

IVM was performed in 160 patients with polycystic ovaries (171 cycles). We administered 10 000 IU hCG s.c. 35–38 h before oocyte collection when endometrial thickness reached at least 6 mm. IVM cycles were retrospectively analyzed according to DF diameter as follows; Group 1: DF diameter ≤10 mm, Group 2: between 10 and 14 mm, Group 3: >14 mm.

A positive correlation was observed between DF size and number of in vivo matured oocytes collected (Group 1, 2 and 3 = 6.9, 10.6 and 15.1%, respectively). The rates of IVM, fertilization and embryo development were similar among the sibling immature oocytes collected from the three groups. However, clinical pregnancy rate in Group 2 (40.3%) was higher than Group 3 (17.1%) (P < 0.05). Moreover, implantation rates in Groups 1 (13.6%) and 2 (14.3%) were higher than Group 3 (4.9%) (P < 0.01).

Our results suggest that oocyte collection in IVM cycles should be performed when the DF is 14 mm diameter or less. Sibling immature oocytes may be affected detrimentally if a DF >14 mm is present at oocyte collection.