Cyclic FEE peptide increases human gamete fusion and potentiates its RGD-induced inhibition.

BACKGROUND: Alpha6beta1 integrin has been proposed to act as a sperm receptor on the mouse oocyte by interacting with spermatozoon fertilin beta. We investigated, in humans, whether oocyte integrins could act similarly in gamete fusion, using a cyclic peptide containing the putative disintegrin-binding domain of human fertilin beta [cyclic FEE (cFEE)] and RGD peptide. METHODS: Zona-free eggs were inseminated in the absence or presence of peptides. To maintain the membrane protein pattern, the zona pellucida was removed by microdissection. Immunofluorescence and confocal microscopy were used to detect integrin subunits on the oocyte. RESULTS: Unexpectedly, cFEE alone increased human gamete fusion by 94% instead of inhibiting fertilization. Furthermore, cFEE together with RGD potentiated the RGD-induced inhibition of fertilization in a dose-dependent manner. The data suggested the hypothesis of integrin cross-talk, further supported by the co-localization of alpha6beta1 and alphavbeta3 integrins, the putative receptors of cFEE and RGD peptides, respectively. CONCLUSIONS: RGD-sensitive and -insensitive integrins may be associated in a multimolecular complex working as a sperm receptor on the human oocyte membrane. Supplementation of human IVF culture medium with cFEE peptide might improve fertilization rates in ART.

[Leucocytospermia, oxidative stress and male fertility: facts and hypotheses]. / Leucospermie, stress oxydatif et fertilité masculine: certitudes et hypothèses.

Leukocytospermia is frequent and significantly increased (over 10(6)/ml) in 20% of male factor infertility. It induces the production of highly toxic reactive oxygen species (ROS) which impair genital track accessory glands and sperm cell functions. The seminal medium contains extremely potent antioxidative defenses which usually balance the oxidative stress. In vivo, these defenses can be overwhelmed when ROS production is extremely important and/or when it lasts for a very long period of time. Infertility can then appear. In vitro, ROS have been univoqually demonstrated for being highly toxic since spermatozoa are no longer protected. Sperm cell defects are : decrease of acrosome reaction and fusiogenic ability and increase of DNA fragmentations. In case of male factor infertility, a leukocytospermia represents an essential or an additional risk factor that should be treated, specially when in vitro therapy is to be scheduled, in order to improve gamete quality.

[Prospective randomized single-blind trial comparing oral sodium phosphate with polyethylene glycol for colonoscopy preparation]. / Etude prospective randomisée en simple aveugle comparant phosphate de sodium oral et polyéthylène glycol pour la préparation à la coloscopie.

AIM AND METHODS: The aim of this prospective, randomized, study performed in 60 outpatients was to compare 2 precolonoscopy bowel preparations: oral sodium phosphate (NaP) versus standard polyethylene glycol-based lavage solution (PEG). None of the patients met any of NaP exclusion criteria. All patients were prepared on the day prior to colonoscopy. A patient-questionnaire and measure of serum electrolytes (calcium, phosphate, sodium, potassium), pulse and blood pressure were used to assess tolerance and acceptability of the preparation. The quality of colon cleansing was judged by blinded endoscopists. RESULTS: Patient's tolerance to NaP was superior to PEG: NaP preparation was easier to drink and feelings of abdominal plenitude occurred in a smaller proportion of patients. A potassium decrease, a sodium increase and hyperphosphatemia were observed in the NaP group but without clinical events. PEG preparation seemed to allow a better cleansing ability compared with NaP but this difference was not statistically significant. CONCLUSIONS: NaP solution was better tolerated and accepted by patients. Colonic preparation quality compared to PEG is still to be discussed depending on the intake schedule. A biochemical data check seems necessary on account of significant serum electrolytes changes induced by NaP preparation.