RESUMEN
OBJECTIVE: To provide a link between epigenetics and male subfertility at the DNA, histone-protamine, and RNA levels and its consequences on fertilization and embryo development. DESIGN: Review of the relevant literature. SETTING: University-based clinical and research laboratories. PATIENT(S): Fertile and infertile men. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Critical review of the literature. RESULT(S): Epigenetic markers can be modified in infertile patients. Epigenetic modifications include methylation loss or gain on the global level and on imprinted genes, high levels of histone retention in spermatozoa, and deficiencies in some transcripts involved in spermatogenesis. Interestingly, these abnormalities are all linked together, because DNA methylation maintenance depends on DNA histone-protamine configuration which itself is stabilized by spermatozoal RNAs. CONCLUSION(S): The paternal genome has long been considered to be silent and passive in embryo formation. The epigenetic processes associated with the paternal DNA genome highlights its importance in male fertility as well as for embryo development.
Asunto(s)
Desarrollo Embrionario/genética , Epigénesis Genética/genética , Fertilidad/genética , Enfermedades Genéticas Congénitas/genética , Infertilidad Masculina/genética , Femenino , Humanos , Masculino , EmbarazoRESUMEN
Oocyte integrins have been described as essential for fertilization. But this concept has been challenged by deletion experiments. Recently, we have shown that sperm integrin alpha6beta1 plays a determinant role in mouse gamete interaction. In this study, we demonstrate the presence of alphavbeta3 integrin by Western blot and immunofluorescence on the sperm membrane. Oocytes and/or sperm preincubations with anti-alphav or anti-beta3 antibodies were performed before in vitro fertilization on cumulus-intact and zona-free egg assays. We observed inhibitory effects on the fusion process mostly by means of sperm function. An antibody directed against vitronectin inhibited gametes fusion, whereas the presence of exogenous vitronectin increased its efficiency. We suggest that vitronectin (on multimeric forms) can play a first nonspecific link corresponding to loosely bound spermatozoa to oocyte and that this link could be mediated by means of oocyte proteoglycans or integrins, and sperm alphavbeta3 integrin.
Asunto(s)
Integrina alfaVbeta3/metabolismo , Espermatozoides/metabolismo , Animales , Femenino , Fertilización , Fertilización In Vitro , Ligandos , Masculino , Membranas/metabolismo , Ratones , Microscopía Fluorescente/métodos , Oocitos/metabolismo , Vitronectina/biosíntesisRESUMEN
DNA methylation marks, a key modification of imprinting, are erased in primordial germ cells and sex specifically re-established during gametogenesis. Abnormal epigenetic programming has been proposed as a possible mechanism compromising male fertility. We analysed by pyrosequencing the DNA methylation status of 47 CpGs located in differentially methylated regions (DMRs), the DMR0 and DMR2 of the IGF2 gene and in the 3rd and 6th CTCF-binding sites of the H19 DMR in human sperm from men with normal semen and patients with teratozoospermia (T) and/or oligo-astheno-teratozoospermia (OAT). All normal semen samples presented the expected high global methylation level for all CpGs analysed. In the teratozoospermia group, 11 of 19 patients presented a loss of methylation at variable CpG positions either in the IGF2 DMR2 or in both the IGF2 DMR2 and the 6th CTCF of the H19 DMR. In the OAT group, 16 of 22 patients presented a severe loss of methylation of the 6th CTCF, closely correlated with sperm concentration. The methylation state of DMR0 and of the 3rd CTCF was never affected by the pathological status of sperm samples. This study demonstrates that epigenetic perturbations of the 6th CTCF site of the H19 DMR might be a relevant biomarker for quantitative defects of spermatogenesis in humans. Moreover, we defined a methylation threshold sustaining the classification of patients in two groups, unmethylated and methylated. Using this new classification of patients, the observed intrinsic imprinting defects of spermatozoa appear not to impair significantly the outcome of assisted reproductive technologies.
Asunto(s)
Epigénesis Genética , Sitios Genéticos/genética , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Factor II del Crecimiento Similar a la Insulina/genética , Espermatozoides/metabolismo , Espermatozoides/patología , Adulto , Sitios de Unión , Estudios de Cohortes , Islas de CpG/genética , Metilación de ADN/genética , Humanos , Masculino , Técnicas Reproductivas Asistidas , Resultado del TratamientoRESUMEN
OBJECTIVE: To report the fatal outcome of a woman with Turner syndrome (TS) undergoing assisted reproductive technology (ART). DESIGN: Case report. SETTING: Reproductive medicine center. PATIENT(S): A 33-year-old woman with TS. INTERVENTION(S): Screening before oocyte donation and treatment of aortic dissection occurring at term pregnancy. MAIN OUTCOME MEASURE(S): Evaluation of cardiovascular risk. RESULT(S): After a normal cardiac screening, a woman with TS got pregnant as a result of oocyte donation. At 16 weeks of gestation, a bicuspid aortic valve was detected and associated with moderate aortic root dilation. Aortic dissection was diagnosed at 38 weeks of gestation, which required emergent cesarean delivery and aortic root replacement. Despite surgical treatment, early maternal death was recorded. CONCLUSION(S): Careful cardiac screening and close follow-up before and during pregnancy are necessary in patients with TS.
