title: Embryological, clinical and ultrastructural study of human oocytes presenting indented zona pellucida.
abstract: Human oocyte dysmorphisms attain a large proportion of retrieved oocytes from assisted reproductive technology (ART) treatment cycles. Extracytoplasmic defects involve abnormal morphology of the zona pellucida (ZP), perivitelline space and first polar body. The aim of the present study was to describe a novel dysmorphism affecting the ZP, indented ZP. We also evaluated the clinical, embryological and ultrastructural features of these cases. We evaluated all ART treatment cycles during 7 consecutive years and found 13 treatment cycles (six patients) with all oocytes presenting an indented ZP. In addition, these oocytes presented total or partial absence of the perivitelline space, absence of resistance to ZP and oolemma penetration during microinjection, and low ooplasm viscosity during aspiration. This novel described dysmorphism was recurrent and attained all oocytes in three cases that had more than one treatment cycle. When compared with controls, data showed significant low oocyte maturity (42% versus 81.6%) and high cycle cancellation (30.8% versus 8.5%) rates, normal degeneration (3.4% versus 6.3%) and fertilization rates (69% versus 69.5%), and low pregnancy (15.4% versus 33.3%) and live-birth delivery (7.7% versus 27.7%) rates per cycle. Ultrastructure analysis revealed a zona pellucida structure with large empty electrolucent regions, an outer ZP layer with an indented surface with protuberances and a thick inner ZP that obliterated the perivitelline space. There was evidence of exocytosis of ZP material by the oocyte. In conclusion, oocytes with this novel described dysmorphism (indented ZP) are associated with low maturity, pregnancy and live-birth delivery rates.
authors.affiliation: Department of Microscopy,Laboratory of Cell Biology,Building 1,Floor 2,Room 10.2.3,Institute of Biomedical Sciences Abel Salazar (ICBAS),University of Porto,Rua Jorge Viterbo Ferreira,228,4050-313 Porto,Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Sousa
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Teixeira da Silva
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Silva
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Cunha
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Viana
authors.affiliation: Department of Microscopy,Laboratory of Cell Biology,UMIB,Institute of Biomedical Sciences Abel Salazar (ICBAS),University of Porto,Rua Jorge Viterbo Ferreira,228,4050-313 Porto,Portugal.
authors.forename: E
authors.initials: E
authors.lastname: Oliveira
authors.affiliation: Department of Microscopy,Laboratory of Cell Biology,UMIB,Institute of Biomedical Sciences Abel Salazar (ICBAS),University of Porto,Rua Jorge Viterbo Ferreira,228,4050-313 Porto,Portugal.
authors.forename: R
authors.initials: R
authors.lastname: Sá
authors.affiliation: Department of Microscopy,Laboratory of Cell Biology,UMIB,Institute of Biomedical Sciences Abel Salazar (ICBAS),University of Porto,Rua Jorge Viterbo Ferreira,228,4050-313 Porto,Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Soares
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Oliveira
authors.affiliation: Centre for Reproductive Genetics Alberto Barros,Av. do Bessa,240,1° Dto. Frente,4100-009 Porto,Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Barros
mesh_terms: D000328:Adult; D046149:Embryo Culture Techniques; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008423:Maternal Age; D009865:Oocytes / Q000473:pathology / Q000502:physiology* / Q000648:ultrastructure*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D020554:Sperm Injections, Intracytoplasmic; D016896:Treatment Outcome; D015044:Zona Pellucida / Q000648:ultrastructure*
keywords: Clinical and embryological outcomes; Indented zona pellucida; Oocyte dysmorphisms; Ultrastructure