Papers by David Albertini
The advent of the epigenetic era has sparked a new frontier in molecular research and the underst... more The advent of the epigenetic era has sparked a new frontier in molecular research and the understanding of how development can be regulated beyond direct alterations of the genome. Thus far, the focal point of epigenetic regulation during development has been chromatin modifications that control differential gene expression by DNA methylation and histone alterations. But what of events that alter gene expression without direct influence on the DNA itself? This review focuses on epigenetic pathways regulating development from oogenesis to organogenesis and back that do not involve methylation of cytosine in DNA. We discuss target components of epigenetic modification such as organelle development, compartmentalization of maternal factors and molecular mediators in the oocyte and how these factors acting during oogenesis impact on later development. Epigenetic regulation of development, be it via cytosine methylation or not, has wide ranging effects on the subsequent success of a preg...
Journal of Assisted Reproduction and Genetics
Oocyte in vitro maturation (IVM) is an assisted reproductive technology designed to obtain mature... more Oocyte in vitro maturation (IVM) is an assisted reproductive technology designed to obtain mature oocytes following culture of immature cumulus–oocyte complexes collected from antral follicles. Although IVM has been practiced for decades and is no longer considered experimental, the uptake of IVM in clinical practice is currently limited. The purpose of this review is to ensure reproductive medicine professionals understand the appropriate use of IVM drawn from the best available evidence supporting its clinical potential and safety in selected patient groups. This group of scientists and fertility specialists, with expertise in IVM in the ART laboratory and/or clinic, explore here the development of IVM towards acquisition of a non-experimental status and, in addition, critically appraise the current and future role of IVM in human ART.
Journal of Assisted Reproduction and Genetics
Journal of Assisted Reproduction and Genetics
Proceedings of the National Academy of Sciences
Journal of assisted reproduction and genetics, 2016
JAMA, 2015
Use of oocytes donated for in vitro fertilization (IVF) has increased in recent years. 1 Donated ... more Use of oocytes donated for in vitro fertilization (IVF) has increased in recent years. 1 Donated fresh oocytes traditionally have been used immediately, creating embryos for transfer into the uterus, with extra embryos being cryopreserved for later use. In January 2013, the American Society for Reproductive Medicine declared the technique of oocyte cryopreservation (egg freezing) no longer experimental, although it called for "more widespread clinic-specific data on the safety and efficacy of oocyte cryopreservation … before universal donor oocyte banking can be recommended." 2 Based on data that IVF outcomes with cryopreserved and fresh donor oocytes are comparable, 3 some IVF centers established frozen donor egg banks. However, data reflecting IVF outcomes in routine clinical practice with cryopreserved donor oocytes have not been published.
Reproductive Biology and Endocrinology, 2015
Background: Low functional ovarian reserve (LFOR) has been associated with hypoandrogenemia and i... more Background: Low functional ovarian reserve (LFOR) has been associated with hypoandrogenemia and increased embryo aneuploidy, while androgen supplementation has been reported to improve aneuploidy rates. We, therefore, assessed whether in infertile women undergoing in vitro fertilization (IVF) androgen concentrations are associated with aneuploidy rates. Methods: This study was performed in 2 academically affiliated fertility centers in New York City and an academically affiliated steroid chemistry laboratory in Utah. Androgen concentrations were measured in blinded fashion from 84 infertile women (age 40.3 +/− 2.4 years) at New York University (NYU), using a validated LC-MS/MS method, in cryopreserved serum samples of patients who had undergone IVF with concomitant preimplantation genetic screening (PGS), utilizing a 24-chromosome platform. The Center for Human Reproduction (CHR) provided plasma samples of 100 historical controls (ages 38.6+/−5.0 years) undergoing IVF without PGS. Statistical comparisons were made of androgen concentrations, and of associations between androgen concentrations and embryo aneuploidy. Results: Women undergoing IVF + PGS at NYU revealed no association between embryo aneuploidy and androgen concentrations but demonstrated significantly lower androgen concentrations than the 100 control patients from CHR, Conclusions: Though this study revealed no association between androgen levels and embryo ploidy, the extremely low androgen levels in the NYU study group raise the possibility of a threshold effect below which testosterone no longer affects aneuploidy. Before an androgen effect on embryo ploidy can be completely ruled out, a patient population with more normal androgen levels has to be investigated.
Journal of assisted reproduction and genetics, 2015
Journal of assisted reproduction and genetics, 2014
The American journal of anatomy, 1987
We have evaluated the distribution of mitochondria and acidic organelles using, respectively, the... more We have evaluated the distribution of mitochondria and acidic organelles using, respectively, the specific vital fluorescent dyes rhodamine 123 and acridine orange during preimplantation embryonic development in the mouse. Under conditions used to visualize organelles in living embryos, staining with either dye was found to have no effect on either the rate or extent of in vitro development of five- to eight-cell embryos up to the blastocyst stage. Mitochondria were randomly distributed throughout the cytoplasm and located around nuclei in blastomeres of uncompacted embryos. During compaction, mitochondria initially reorganized to the blastomere cortex; however, these organelles were later confined to the perinuclear region in the trophectoderm (TE) of expanded blastocysts. Acidic organelles were randomly distributed in the cytoplasm of uncompacted embryos, but following compaction, they were concentrated in cortical and perinuclear locations. Moreover, in TE cells of expanded blast...
Journal of Assisted Reproduction and Genetics, 2014
To test the effects of varying vitrification protocols on the cell cycle status and chromosomal i... more To test the effects of varying vitrification protocols on the cell cycle status and chromosomal integrity in cumulus-enclosed GV stage rat oocytes. Vitrified and thawed rat oocytes were labeled with fluorescent markers for chromatin, cell cycle activation, and f-actin and analyzed by conventional and laser scanning confocal microscopy. In all vitrification groups, significant alterations in cumulus cell connectivity, cell cycle status, and cytoplasmic actin integrity were observed following warming compared to fresh control oocytes. Based on the protein phosphorylation marker MPM-2, it is clear that warmed oocytes rapidly enter M-phase but are unable to maintain chromosome integrity as a result of multiple chromatin fusions. A prominent reduction in f-actin is evident in both the ooplasm and at the cortex of vitrified oocytes. Finally, an irreversible but irregular retraction of TZPs occurs on the majority of oocytes subjected to any of the vitrification protocols. These findings draw attention to undesirable consequences of immature oocyte vitrification that compromise cell cycle status and chromatin and cytoskeleton integrity that may not be evident until after fertilization.
Journal of Assisted Reproduction and Genetics, 2010
Human Reproduction, 2005
BACKGROUND: Deficiencies remain in the ability of in vitro-matured human oocytes to acquire full ... more BACKGROUND: Deficiencies remain in the ability of in vitro-matured human oocytes to acquire full developmental competence and give rise to a healthy pregnancy. A clear deficiency of current systems utilizing human oocytes has been the absence of cumulus cells. In the present study, a three-dimensional (3D) co-culture system exploiting an extracellular matrix was developed and compared to conventional methods for its ability to support maturation of human oocytes. METHODS AND RESULTS: Cumulus cells were embedded into a 3D collagen gel matrix with individual oocytes added to each gel. Oocytes from the same patient cultured in the gel matrix matured to metaphase II at rates similar to those of cumulus-free oocytes cultured in individual microdrops. Following maturation of oocytes and fixation of intact gels, chromatin and cytoskeletal elements were assessed in oocytes and cumulus cells. The activities of the key cell cycle kinases, maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK), were compared in oocytes matured under the two culture conditions. Compared with denuded oocytes, cocultured oocytes exhibited increased MAPK activity, but no difference in MPF levels. CONCLUSIONS: This work characterizes a novel and efficacious culture system that takes advantage of the unique properties of the extracellular matrix, a 3D microenvironment, and the presence of cumulus cells for maturing human oocytes in vitro.
Human …, 2005
BACKGROUND: Deficiencies remain in the ability of in vitro-matured human oocytes to acquire full ... more BACKGROUND: Deficiencies remain in the ability of in vitro-matured human oocytes to acquire full developmental competence and give rise to a healthy pregnancy. A clear deficiency of current systems utilizing human oocytes has been the absence of cumulus cells. In the present study, a three-dimensional (3D) co-culture system exploiting an extracellular matrix was developed and compared to conventional methods for its ability to support maturation of human oocytes. METHODS AND RESULTS: Cumulus cells were embedded into a 3D collagen gel matrix with individual oocytes added to each gel. Oocytes from the same patient cultured in the gel matrix matured to metaphase II at rates similar to those of cumulus-free oocytes cultured in individual microdrops. Following maturation of oocytes and fixation of intact gels, chromatin and cytoskeletal elements were assessed in oocytes and cumulus cells. The activities of the key cell cycle kinases, maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK), were compared in oocytes matured under the two culture conditions. Compared with denuded oocytes, cocultured oocytes exhibited increased MAPK activity, but no difference in MPF levels. CONCLUSIONS: This work characterizes a novel and efficacious culture system that takes advantage of the unique properties of the extracellular matrix, a 3D microenvironment, and the presence of cumulus cells for maturing human oocytes in vitro.
American journal of …, 1987
We have evaluated the distribution of mitochondria and acidic organelles using, respectively, the... more We have evaluated the distribution of mitochondria and acidic organelles using, respectively, the specific vital fluorescent dyes rhodamine 123 and acridine orange during preimplantation embryonic development in the mouse. Under conditions used to visualize organelles in living embryos, staining with either dye was found to have no effect on either the rate or extent of in vitro development of five- to eight-cell embryos up to the blastocyst stage. Mitochondria were randomly distributed throughout the cytoplasm and located around nuclei in blastomeres of uncompacted embryos. During compaction, mitochondria initially reorganized to the blastomere cortex; however, these organelles were later confined to the perinuclear region in the trophectoderm (TE) of expanded blastocysts. Acidic organelles were randomly distributed in the cytoplasm of uncompacted embryos, but following compaction, they were concentrated in cortical and perinuclear locations. Moreover, in TE cells of expanded blastocysts, acidic organelles were found exclusively in a tight perinuclear pattern. Microtubules and microfilaments in TE cells were localized in fixed embryos stained with antitubulin antibodies and rhodamine phalloidin, respectively; these structures were found primarily in the cortical cytoplasm at areas of cell-cell contact and secondarily in a perinuclear location. Thus mitochondria and acidic organelles undergo stage-specific redistributions from a diffuse or cortical pattern at the eight-cell stage to a tight perinuclear localization in the TE. We conclude that the polarized distributions of some organelles and cytoskeletal proteins during compaction may not be reliable permanent markers of the mature TE.
Journal of assisted reproduction and genetics, 2016
In the pig, the efficiency of in vitro embryo production and somatic cell nuclear transfer (SCNT)... more In the pig, the efficiency of in vitro embryo production and somatic cell nuclear transfer (SCNT) procedures remains limited. It has been suggested that prematuration treatments (pre-IVM) based on the prolongation of a patent, bidirectional crosstalk between the oocyte and the cumulus cells through gap junction mediate communication (GJC), with the maintenance of a proper level of cAMP, could improve the developmental capability of oocytes. The aim of this study was to assess: 1) dose-dependent effects of cilostamide on nuclear maturation kinetics, 2) the relationship between treatments on GJC functionality and large-scale chromatin configuration changes, and 3) the impact of treatments on developmental competence acquisition after parthenogenetic activation (PA) and SCNT. Accordingly, cumulus-oocyte complexes were collected from 3to 6-mm antral follicles and cultured for 24 h in defined culture medium with or without 1 lM cilostamide. GJC functionality was assessed by Lucifer yellow microinjection, while chromatin configuration was evaluated by fluorescence microscopy after nuclear staining. Cilostamide administration sustained functional coupling for up to 24 h of culture and delayed meiotic resumption, as only 25.6% of cilostamide-treated oocytes reached the pro-metaphase I stage compared to the control (69.7%; P , 0.05). Moreover, progressive chromatin condensation was delayed before meiotic resumption based upon G2/M biomarker phosphoprotein epitope acquisition using immunolocalization. Importantly, cilostamide treatment under these conditions improved oocyte developmental competence, as reflected in higher blastocyst quality after both parthenogenetic activation and SCNT.
Uploads
Papers by David Albertini