In vitro and in vivo development of domestic cat embryos generated by in vitro fertilization after eCG priming and oocyte in vitro maturation.

The objective of this study was to evaluate, in the domestic cat, the effect of ovarian stimulation with eCG prior to oocyte in vitro maturation (priming) on in vitro and in vivo development after in vitro fertilization (IVF). For this purpose, oocyte donors were either 1) treated with a single dose of 200 IU eCG four days before oocyte recovery (eCG group), or, 2) given no treatment before oocyte recovery (control group). Ovaries of both groups were collected by ovariohysterectomy (OVH) and cumulus-oocyte complexes (COCs) were recovered by slicing. Immature COCs from both groups were matured in vitro (IVM) for 26-28 h. IVF was done with refrigerated epididymal sperm. After 24 h co-incubation, presumptive zygotes were cultured in vitro for eight days. The rates of cleavage, morulae, blastocyst development and hatching were estimated. Some blastocysts were stained for total cell counting and others were used for gene expression analysis of pluripotency (OCT4, SOX2 and NANOG) and differentiation markers (CDX2 and GATA6). Additionally, to evaluate in vivo development, embryos from the eCG group were transferred at Day 5 and Days 7 or 8 of IVC to synchronized cat recipients. The results showed that, eCG priming increased significantly the rate of blastocyst development as compared to the control group (37.9 and 25.6%, respectively) (P < 0.05). No differences were observed in total cell number of blastocysts and hatching blastocysts (mean ± SD) between the eCG and control groups (420.6 ± 193.6 and 347.0 ± 237.1, respectively) (P > 0.05). In the gene expression analysis, blastocysts generated in the eCG group had higher expression of OCT4 than blastocysts from the control group (P < 0.05). However, no significant differences were observed in the relative expression of SOX2, NANOG, CDX2 and GATA6 (P > 0.05). Additionally, six embryo transfer (ET) procedures were done, three with Day 5 embryos and three with Day 7 or 8 embryos. Recipients from both ET groups delivered live kittens. The total pregnancy rate was 4/6 (67%), meanwhile the live birth rate was 2/6 (33%). In conclusion, eCG priming improved the rate of blastocyst development in vitro and increased relative expression of OCT4. These results demonstrate that eCG priming of oocytes donors before IVM improves oocyte competence, enhance in vitro embryo development and allows live births of healthy offspring after ET.

Asociación síndrome de Down-esclerosis tuberosa y sus similitudes en la sobreactivación de las vías m-TOR. A propósito de un caso / Association of Down syndrome and tuberous sclerosis and their similarities in m-TOR pathway overactivation. About a case

Antecedentes. La asociación entre síndrome de Down y esclerosis tuberosa (SD/ET) muy pocas veces ha sido descrita. Estas 2 entidades presentan en común una sobreactivación del sistema m-TOR (ligando para rapamicina mamífero-específico), la que se ha visto relacionada con crecimiento neuronal anómalo, transducción sináptica anómala y sobreestimulación de neurotransmisores en diferentes áreas cerebrales, entre otras, que se manifiestan en retardo cognitivo y síntomas autistas en los pacientes en quienes se presentan. Presentamos el caso de una niña con diagnóstico de SD, quien comenzó a temprana edad con crisis convulsivas tónico-clónicas y placas hipopigmentadas en piel. Se practicó una resonancia cerebral, la cual evidenció imágenes de túberes corticales sugestivas de ET. Un ecocardiograma posterior evidenció la presencia de múltiples lesiones endomiocárdicas sugestivas de rabdomiomas. Controles ulteriores mostraron resolución espontánea de estas lesiones cardiacas, pero con persistencia de las alteraciones cerebrales. Se describe la refractariedad de los episodios convulsivos a pesar de tratamiento apropiado con múltiples anticonvulsivantes. Conclusiones. Las implicaciones neurológicas y cardiacas en pacientes con asociación SD/ET ocupan un escenario terapéutico difícil, con alta tasa de complicaciones, en parte debidas a la refractariedad sintomática. Los nuevos medicamentos dirigidos hacia la vía de señalización m-TOR podrían ser de gran utilidad en este escenario, dada su relación con la mejoría del deterioro cognitivo y las tumoraciones asociadas a estas 2 entidades (AU)

Background. The association between Down syndrome and Tuberous sclerosis (DS/TSC) has very rarely been described. These two entities present in common overactivation of the m-TOR system (mammalian rapamycin ligand), which has been related to abnormal neuronal growth, abnormal synaptic transduction and neurotransmitter overstimulation in different brain areas (among others) that result in cognitive retardation and autistic symptoms. Case summary. We present a girl with a diagnosis of DS, with early childhood onset presenting convulsive tonic-clonic seizures and hypopigmented skin plaques. A brain MRI revealed cortical tubers suggestive of TSC. A subsequent echocardiogram showed the presence of multiple endomyocardial lesions suggestive of rhabdomyoma. Further follow-ups showed spontaneous resolution of these cardiac lesions, but persistence of brain disorders. We also describe the refractoriness of the convulsive events despite appropriate treatment with multiple anticonvulsants. Conclusions. Neurological and cardiac implications in patients with DS/TSC association lead to a difficult therapeutic scenario with a high rate of complications, partially due to symptomatic refractoriness. New drugs aimed at the m-TOR signalling pathway could be very useful in this picture, given its relationship to improvement of cognitive impairment and tumours associated with these two entities (AU)