Concept: In vitro fertilisation
Development of assisted reproductive technologies (ART) in the dog has resisted progress for decades, due to their unique reproductive physiology. This lack of progress is remarkable given the critical role ART could play in conserving endangered canid species or eradicating heritable disease through gene-editing technologies-an approach that would also advance the dog as a biomedical model. Over 350 heritable disorders/traits in dogs are homologous with human conditions, almost twice the number of any other species. Here we report the first live births from in vitro fertilized embryos in the dog. Adding to the practical significance, these embryos had also been cryopreserved. Changes in handling of both gametes enabled this progress. The medium previously used to capacitate sperm excluded magnesium because it delayed spontaneous acrosome exocytosis. We found that magnesium significantly enhanced sperm hyperactivation and ability to undergo physiologically-induced acrosome exocytosis, two functions essential to fertilize an egg. Unlike other mammals, dogs ovulate a primary oocyte, which reaches metaphase II on Days 4-5 after the luteinizing hormone (LH) surge. We found that only on Day 6 are oocytes consistently able to be fertilized. In vitro fertilization of Day 6 oocytes with sperm capacitated in medium supplemented with magnesium resulted in high rates of embryo development (78.8%, n = 146). Intra-oviductal transfer of nineteen cryopreserved, in vitro fertilization (IVF)-derived embryos resulted in seven live, healthy puppies. Development of IVF enables modern genetic approaches to be applied more efficiently in dogs, and for gamete rescue to conserve endangered canid species.
Multiple scattering limits the contrast in optical imaging of thick specimens. Here, we present gradient light interference microscopy (GLIM) to extract three-dimensional information from both thin and thick unlabeled specimens. GLIM exploits a special case of low-coherence interferometry to extract phase information from the specimen, which in turn can be used to measure cell mass, volume, surface area, and their evolutions in time. Because it combines multiple intensity images that correspond to controlled phase shifts between two interfering waves, gradient light interference microscopy is capable of suppressing the incoherent background due to multiple scattering. GLIM can potentially become a valuable tool for in vitro fertilization, where contrast agents and fluorophores may impact the viability of the embryo. Since GLIM is implemented as an add-on module to an existing inverted microscope, we anticipate that it will be adopted rapidly by the biological community.Challenges in biological imaging include labeling, photobleaching and phototoxicity, as well as light scattering. Here, Nguyen et al. develop a quantitative phase method that uses low-coherence interferometry for label-free 3D imaging in scattering tissue.
The purpose of this study is to to compare the efficacy of intravaginal culture (IVC) of embryos in INVOcell™ (INVO Bioscience, MA, USA) to traditional in vitro fertilization (IVF) incubators in a laboratory setting using a mild pre-determined stimulation regimen based solely on anti-mullerian hormone (AMH) and body weight with minimal ultrasound monitoring. The primary endpoint examined was total quality blastocysts expressed as a percentage of total oocytes placed in incubation. Secondary endpoints included percentage of quality blastocysts transferred, pregnancy, and live birth rates.
BACKGROUNDGenetic testing of preimplantation embryos has been used for preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS). Microarray technology is being introduced in both these contexts, and whole genome sequencing of blastomeres is also expeted to become possible soon. The amount of extra information such tests will yield may prove to be beneficial for embryo selection, will also raise various ethical issues. We present an overview of the developments and an agenda-setting exploration of the ethical issues.METHODSThe paper is a joint endeavour by the presenters at an explorative ‘campus meeting’ organized by the European Society of Human Reproduction and Embryology in cooperation with the department of Health, Ethics & Society of the Maastricht University (The Netherlands).RESULTSThe increasing amount and detail of information that new screening techniques such as microarrays and whole genome sequencing offer does not automatically coincide with an increasing understanding of the prospects of an embryo. From a technical point of view, the future of comprehensive embryo testing may go together with developments in preconception carrier screening. From an ethical point of view, the increasing complexity and amount of information yielded by comprehensive testing techniques will lead to challenges to the principle of reproductive autonomy and the right of the child to an open future, and may imply a possible larger responsibility of the clinician towards the welfare of the future child. Combinations of preconception carrier testing and embryo testing may solve some of these ethical questions but could introduce others.CONCLUSIONSAs comprehensive testing techniques are entering the IVF clinic, there is a need for a thorough rethinking of traditional ethical paradigms regarding medically assisted reproduction.
OBJECTIVE: To determine the diagnostic value of the following sperm function tests in predicting the fertilizing ability of spermatozoa in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI): hyaluronan-binding assay (HBA), DNA fragmentation (Halosperm), and hyperactivity. DESIGN: Prospective study. SETTING: University medical center. PATIENT(S): 133 couples undergoing infertility treatment with IVF/ICSI. INTERVENTION(S): Analysis of sperm DNA fragmentation, hyaluronan-binding ability, and hyperactivation on washed semen samples used for the insemination of oocytes. MAIN OUTCOME MEASURE(S): Correlation between the results of sperm function tests and the fertilization rate (FR) or embryo quality (EQ) after IVF and ICSI. Comparison of the sperm DNA fragmentation, hyperactivation, and hyaluronan binding ability between cycles with less than 50% (group 1) and more than 50% (group 2) of oocytes fertilized after IVF. RESULT(S): Both FR and EQ in IVF cycles negatively correlated with sperm DNA fragmentation. Furthermore, a positive correlation was observed between FR and hyaluronan-binding ability or induced hyperactivity. The semen samples from the IVF cycles with low FR (group 1) were characterized by statistically significantly higher sperm DNA fragmentation and lower hyaluronan-binding ability in comparison with semen samples from the group with high levels of fertilization (group 2). In ICSI cycles, no relationship was found between sperm function tests and FR or EQ. CONCLUSION(S): The Halosperm test, the HBA test, and induced hyperactivity are useful in predicting the ability of spermatozoa to fertilize oocytes in IVF and are helpful in distinguishing semen samples suitable for IVF or ICSI.
Despite a strict requirement for sterol removal for sperm to undergo acrosome exocytosis (AE), the mechanisms by which changes in membrane sterols are transduced into changes in sperm fertilization competence are poorly understood. We have previously shown in live murine sperm that the plasma membrane overlying the acrosome (APM) contains several types of micro-domains known as membrane rafts. When characterizing the membrane raft-associated proteomes, we identified phospholipase B (PLB), a calcium-independent enzyme exhibiting multiple activities. Here, we show that sperm surface PLB is activated in response to sterol removal. Both biochemical activity assays and immunoblots of sub-cellular fractions of sperm incubated with the sterol acceptor 2-hydroxypropyl-β-cyclodextrin (2-OHCD) confirmed the release of an active PLB fragment. Specific protease inhibitors prevented PLB activation, revealing a mechanistic requirement for proteolytic cleavage. Competitive inhibitors of PLB reduced both the ability of sperm to undergo AE and to fertilize oocytes in vitro, suggesting an important role in fertilization. This was reinforced by our finding that incubation with either protein concentrate released from 2-OHCD-treated sperm, or with recombinant PLB peptide corresponding to the catalytic domain, were both able to induce AE in the absence of other stimuli. Together, these results lead us to propose a novel mechanism by which sterol removal promotes membrane fusogenicity and AE, helping confer fertilization competence. Importantly, this mechanism provides a basis for the newly emerging model of AE in which membrane fusions occur during capacitation/transit through the cumulus, prior to any physical contact between the sperm and the oocyte’s zona pellucida.
The current study aimed to evaluate the effects of phosalone (PLN) as an organophosphate (OP) compound on testicular tissue, hormonal alterations and embryo development in rats.
The emerging multidrug-resistant yeast pathogen Candida auris has attracted considerable attention as a source of healthcare-associated infections. We report that this highly virulent yeast has the capacity to form antifungal resistant biofilms sensitive to the disinfectant chlorhexidine in vitro.
Children conceived by assisted reproductive technologies (ART) display a level of vascular dysfunction similar to that seen in children of mothers with preeclamspia. The long-term consequences of ART-associated vascular disorders are unknown and difficult to investigate in healthy children. Here, we found that vasculature from mice generated by ART display endothelial dysfunction and increased stiffness, which translated into arterial hypertension in vivo. Progeny of male ART mice also exhibited vascular dysfunction, suggesting underlying epigenetic modifications. ART mice had altered methylation at the promoter of the gene encoding eNOS in the aorta, which correlated with decreased vascular eNOS expression and NO synthesis. Administration of a deacetylase inhibitor to ART mice normalized vascular gene methylation and function and resulted in progeny without vascular dysfunction. The induction of ART-associated vascular and epigenetic alterations appeared to be related to the embryo environment; these alterations were possibly facilitated by the hormonally stimulated ovulation accompanying ART. Finally, ART mice challenged with a high-fat diet had roughly a 25% shorter life span compared with control animals. This study highlights the potential of ART to induce vascular dysfunction and shorten life span and suggests that epigenetic alterations contribute to these problems.
Use of glyphosate-based herbicides (GBHs) increased ∼100-fold from 1974 to 2014. Additional increases are expected due to widespread emergence of glyphosate-resistant weeds, increased application of GBHs, and preharvest uses of GBHs as desiccants. Current safety assessments rely heavily on studies conducted over 30 years ago. We have considered information on GBH use, exposures, mechanisms of action, toxicity and epidemiology. Human exposures to glyphosate are rising, and a number of in vitro and in vivo studies challenge the basis for the current safety assessment of glyphosate and GBHs. We conclude that current safety standards for GBHs are outdated and may fail to protect public health or the environment. To improve safety standards, the following are urgently needed: (1) human biomonitoring for glyphosate and its metabolites; (2) prioritisation of glyphosate and GBHs for hazard assessments, including toxicological studies that use state-of-the-art approaches; (3) epidemiological studies, especially of occupationally exposed agricultural workers, pregnant women and their children and (4) evaluations of GBHs in commercially used formulations, recognising that herbicide mixtures likely have effects that are not predicted by studying glyphosate alone.