ICSI diagnostic: a way to prevent total fertilization failure after 4 unsuccessful IUI.

BACKGROUND: The aim of this retrospective study is to investigate the relevance of dividing oocytes and using some for traditional in vitro fertilization (IVF) and others for intracytoplasmic sperm injection (ICSI) as of the first IVF cycle in patients with unexplained infertility who have undergone 4 intrauterine insemination (IUI) cycles which produced no pregnancies. METHODS: This retrospective study includes patients with unexplained infertility who have failed to become pregnant, after 4 IUI, despite normal semen parameters after sperm capacitation. These women were treated in our assisted fertilization program from 2008 until 2015. We analysed the first cycles of women in whom more than 4 oocyte cumulus complexes (OCC) were retrieved and single embryo transfer was performed. RESULTS: Dividing oocytes between two fertilization techniques reduce the rate of total fertilization failure during the first IVF cycle. No statistical difference were observed for 2 pronuclei (PN) rate between the two techniques. On the other hand, we observed a significantly lower rate of 3 PN, 1 PN, 0 PN with ICSI in comparison with conventional fertilization. CONCLUSIONS: Splitting the oocytes between classical IVF and ICSI increases the chance of embryo transfer on a first IVF cycle after 4 unsuccessful IUI cycles. This half-and-half policy reduces the risk, for the infertile couple, of facing total failure of fertilization and also can provide useful information for the next attempts.

CONTEXTE: L'objectif de cette étude rétrospective est. de montrer la pertinence de répartir les ovocytes ponctionnés entre deux méthodes de fécondation, la fécondation classique (IVF) et l'injection de sperme intra cytoplamisque (ICSI), lors d'un premier cycle de stimulation après 4 essais insémination intra-utérine (IUI) infructueuses. MÉTHODES: Cette étude rétrospective inclut les patientes ayant réalisés 4. inséminations intra utérine sans grossesse entre 2008 et 2015. Les paramètres du sperme sont normaux. Nous avons analysé les cycles de stimulation de rang 1 des patientes où minimum 4 ovocytes ont été prélevés et un seul embryon transféré. RÉSULTATS: Répartir les ovocytes entre les deux techniques de fécondation réduit le taux d'échec de fécondation total lors du premier cycle de stimulation. Aucune différence statistique n'a été observée entre les taux de 2 pronuclei (PN) pour les deux méthodes de fécondation. Toutefois une réduction significative est. observée pour les taux de 3 PN, 1 PN et 0 PN en faveur de l'ICSI. CONCLUSION: La répartition des ovocytes lors d'un premier essai de fécondation in vitro réalisé après 4 échecs d'insémination intra-utérine, permet d'augmenter les chances d'aboutir à un transfert d'embryons. Cette procédure réduit les risques d'avoir un échec total de fécondation chez des couples infertile et permet d'obtenir des informations pour les essais ultérieurs.

Fgf receptors Fgfr1a and Fgfr2 control the function of pharyngeal endoderm in late cranial cartilage development.

Cranial cartilage derives mainly from cranial neural crest cells and its formation requires fibroblast growth factor (Fgf) signaling for early differentiation and survival of developing chondrocytes as well as patterning of the endodermal pouches. Here, we investigate the role of Fgf receptors in chondrocyte maturation at later stages, beyond 24 hpf. Using inducible expression of a dominant-negative Fgf receptor, we show that Fgf signaling is required around 30 hpf for correct cartilage formation. The receptor genes fgfr1a and fgr2 are expressed in pharyngeal endodermal pouches after 24 hpf or 26 hpf, respectively. Depletion of any of these two receptors by microinjection of antisense morpholinos results in severe defects in cartilage formation at 4 dpf and a decrease in expression of the late chondrocyte markers barx1 and runx2b. Although endodermal pouches are correctly formed and patterned, receptor knock down leads to decreased expression of runx3, egr1 and sox9b in this tissue, while expression of fsta, coding for a secreted BMP/Tgfß inhibitor, is clearly increased. Rescue experiments revealed that each Fgfr1a or Fgfr2 receptor is able to compensate for the loss of the other. Thus, we show that minimal amounts of Fgfr1a or Fgfr2 are required to initiate a regulatory cascade in pharyngeal endoderm reducing expression of fsta, thereby allowing correct BMP signaling to the maturing chondrocytes of the head cartilage.

RUNX3, EGR1 and SOX9B form a regulatory cascade required to modulate BMP-signaling during cranial cartilage development in zebrafish.

The cartilaginous elements forming the pharyngeal arches of the zebrafish derive from cranial neural crest cells. Their proper differentiation and patterning are regulated by reciprocal interactions between neural crest cells and surrounding endodermal, ectodermal and mesodermal tissues. In this study, we show that the endodermal factors Runx3 and Sox9b form a regulatory cascade with Egr1 resulting in transcriptional repression of the fsta gene, encoding a BMP antagonist, in pharyngeal endoderm. Using a transgenic line expressing a dominant negative BMP receptor or a specific BMP inhibitor (dorsomorphin), we show that BMP signaling is indeed required around 30 hpf in the neural crest cells to allow cell differentiation and proper pharyngeal cartilage formation. Runx3, Egr1, Sox9b and BMP signaling are required for expression of runx2b, one of the key regulator of cranial cartilage maturation and bone formation. Finally, we show that egr1 depletion leads to increased expression of fsta and inhibition of BMP signaling in the pharyngeal region. In conclusion, we show that the successive induction of the transcription factors Runx3, Egr1 and Sox9b constitutes a regulatory cascade that controls expression of Follistatin A in pharyngeal endoderm, the latter modulating BMP signaling in developing cranial cartilage in zebrafish.