Cloning for the Twenty-First Century and Its Place in Endangered Species Conservation

Cloning as it relates to the animal kingdom generally refers to the production of genetically identical individuals. Because cloning is increasingly the subject of renewed attention as a tool for rescuing endangered or extinct species, it seems timely to dissect the role of the numerous reproductive techniques encompassed by this term in animal species conservation. Although cloning is typically associated with somatic cell nuclear transfer, the recent advent of additional techniques that allow genome replication without genetic recombination demands that the use of induced pluripotent stem cells to generate gametes or embryos, as well as older methods such as embryo splitting, all be included in this discussion. Additionally, the phenomenon of natural cloning (e.g., a subset of fish, birds, invertebrates, and reptilian species that reproduce via parthenogenesis) must also be pointed out. Beyond the biology of these techniques are practical considerations and the ethics of using cloning and associated procedures in endangered or extinct species. All of these must be examined in concert to determine whether cloning has a place in species conservation. Therefore, we synthesize progress in cloning and associated techniques and dissect the practical and ethical aspects of these methods as they pertain to endangered species conservation.

The neonatal southern white rhinoceros ovary contains oogonia in germ cell nests

The northern white rhinoceros is functionally extinct with only two females left. Establishing methods to culture ovarian tissues, follicles, and oocytes to generate eggs will support conservation efforts using in vitro embryo production. To the best of our knowledge, this is the first description of the structure and molecular signature of any rhinoceros, more specifically, we describe the neonatal and adult southern white rhinoceros (Ceratotherium simum simum) ovary; the closest relation of the northern white rhinoceros. Interestingly, all ovaries contain follicles despite advanced age. Analysis of the neonate reveals a population of cells molecularly characterised as mitotically active, pluripotent with germ cell properties. These results indicate that unusually, the neonatal ovary still contains oogonia in germ cell nests at birth, providing an opportunity for fertility preservation. Therefore, utilising ovaries from stillborn and adult rhinoceros can provide cells for advanced assisted reproductive technologies and investigating the neonatal ovaries of other endangered species is crucial for conservation.

Rescue of follicle development after oocyte-induced ovary dysfunction and infertility in a model of POI

The mechanisms and aetiology underlying the development of premature ovarian insufficiency (POI) are poorly understood. However, the oocyte clearly has a role as demonstrated by the Double Mutant (DM) mouse model where ovarian dysfunction (6 weeks) is followed by POI (3 months) due to oocyte-specific deletion of complex and hybrid N- and O-glycans. The ovaries of DM mice contain more primary follicles (3a stage) accompanied by fewer developing follicles, indicating a block in follicle development. To investigate this block, we first analysed early follicle development in postnatal (8-day), pre-pubertal (3-week) and post-pubertal (6-week and 3-month) DM (C1galt1 F/F Mgat1 F/F:ZP3Cre) and Control (C1galt1 F/F Mgat1 F/F) mice. Second, we investigated if transplantation of DM ovaries into a "normal" endocrine environment would restore follicle development. Third, we determined if replacing DM ovarian somatic cells would rescue development of DM oocytes. At 3-week, DM primary 3a follicles contain large oocytes accompanied by early development of a second GC layer and increased GC proliferation. At 6-week, DM primary 3a follicles contain abnormally large oocytes, accompanied with decreased GC proliferation. Transplantation of DM ovaries into a 'normal' endocrine environment did not restore normal follicle development. However, replacing somatic cells by generating reaggregated ovaries (ROs) did enable follicle development to progress and thus highlighted intra-ovarian factors were responsible for the onset of POI in DM females. Thus, these studies demonstrate oocyte-initiated altered communication between GCs and oocytes results in abnormal primary follicles which fail to progress and leads to POI.

Cloning in action: can embryo splitting, induced pluripotency and somatic cell nuclear transfer contribute to endangered species conservation?

The term 'cloning' refers to the production of genetically identical individuals but has meant different things throughout the history of science: a natural means of reproduction in bacteria, a routine procedure in horticulture, and an ever-evolving gamut of molecular technologies in vertebrates. Mammalian cloning can be achieved through embryo splitting, somatic cell nuclear transfer, and most recently, by the use of induced pluripotent stem cells. Several emerging biotechnologies also facilitate the propagation of genomes from one generation to the next whilst bypassing the conventional reproductive processes. In this review, we examine the state of the art of available cloning technologies and their progress in species other than humans and rodent models, in order to provide a critical overview of their readiness and relevance for application in endangered animal conservation.

Rapid ovarian transcript changes during the onset of premature ovarian insufficiency

The manuscript has been submitted without altering abstract in line with Reproduction's Flexible Submission Process. The abstract is extended and thus does not fit this space.

Comparative effectiveness and cardiovascular safety of abaloparatide and teriparatide in postmenopausal women new to anabolic therapy: A US administrative claims database study

Real-world evidence on the comparative effectiveness and safety of abaloparatide versus teriparatide in women with osteoporosis may help inform treatment decisions. Following 18 months of treatment, abaloparatide was comparable to teriparatide for prevention of nonvertebral fractures, resulted in a 22% risk reduction for hip fractures, and demonstrated similar cardiovascular safety. Osteoporotic fracture risk can be reduced with anabolic or antiresorptive medications. In addition to efficacy and safety data from controlled clinical trials, real-world evidence on comparative effectiveness and safety may help inform treatment decisions.

INTRODUCTION

The real-world effectiveness of abaloparatide versus teriparatide on nonvertebral fracture (NVF) incidence and cardiovascular safety during the 19-month period after treatment initiation were evaluated (NCT04974723).

METHODS

Anonymized US patient claims data from Symphony Health, Integrated Dataverse (IDV)®, May 1, 2017 to July 31, 2019, included women aged ≥ 50 years with ≥ 1 prescription of abaloparatide or teriparatide and no prior anabolic therapy. Most were enrolled in commercial and Medicare health plans. Index was the date of the initial prescription dispensed during the identification period. In 1:1 propensity score matched cohorts, time to first NVF following index date, major adverse cardiovascular events (MACE), and MACE + heart failure (HF) were compared between cohorts using a Cox proportional hazards model.

RESULTS

Propensity score matching yielded 11,616 patients per cohort. Overall median age (interquartile range) was 67 (61, 75) years, and 25.6% had a fracture history. Over 19 months, 335 patients on abaloparatide and 375 on teriparatide had a NVF (hazard ratio [95% confidence interval]: 0.89 [0.77, 1.03]), and 121 and 154 patients, respectively, had a hip fracture [HR (95% CI): 0.78 (0.62, 1.00)]. The MACE and MACE + HF rates were similar between cohorts.

CONCLUSIONS

Following 18 months of treatment, abaloparatide was comparable to teriparatide for prevention of NVF and similar cardiovascular safety was demonstrated between cohorts.

No evidence for age-related differences in mitochondrial RNA quality in the female germline

Abstract

Mitochondrial quality is implicated as a contributor to declining fertility with aging. We investigated mitochondrial transcripts in oocytes and their associated cumulus cells from mice of different ages using RNA-seq. Mice aged 3 weeks, 9 weeks, and 1 year were superovulated, and 48 h later, oocyte cumulus complexes were collected by follicle puncture. We did not detect any major differences that could be attributed to aging. However, mitochondrial RNA transcripts which deviated from the consensus sequence were found at a higher frequency in cumulus cells than in their corresponding oocyte. Previous investigations have shown that variation in the sequence of mtRNA transcripts is substantial, and at least some of this can be accounted for by post-transcriptional modifications which impact base calling during sequencing. Our data would be consistent with either less post-transcriptional modification in mitochondrial RNA from oocytes than cumulus cells or with lower mtDNA mutational load.

Lay summary

Women become less fertile as they age. Shortage of energy contributes to this, caused by a decline in the quality of mitochondria (the powerhouses of the cell) in the egg. Genes are the blueprint for the cell. They are made of DNA which is copied into an RNA message, or instructions, for making proteins. We counted differences in the RNA message of developing eggs and the cells that support them during development (cumulus cells). We compared the number of these differences in mice of different ages. These age groups represent mice had not reached puberty, those of prime reproductive age, and old mothers. We did not find any differences linked to the age of the mice. However, we did find differences between the egg and the cumulus cells. In most cases, there were lower levels of mutations in eggs than there were in cumulus cells.

Analysing culture methods of frozen human ovarian tissue to improve follicle survival

In vitro follicle growth is a potential fertility preservation method for patients for whom current methods are contraindicated. Currently, this method has only been successful using fresh ovarian tissue. Since many patients who may benefit from this treatment currently have cryopreserved ovarian tissue in storage, optimising in vitro follicle growth (IVG) for cryopreserved-thawed tissue is critical. This study sought to improve the first step of IVG by comparing different short-term culture systems for cryopreserved-thawed human ovarian tissue, in order to yield a higher number of healthy multilayer follicles. We compared two commonly used culture media (αMEM and McCoy’s 5A), and three plate conditions (300 µL, 1 mL on a polycarbonate membrane and 1 mL in a gas-permeable plate) on the health and development of follicles after 6 days of culture. A total of 5797 follicles from three post-pubertal patients (aged 21.3 ± 2.3 years) were analysed across six different culture conditions and non-cultured control. All culture systems supported follicle development and there was no difference in developmental progression between the different conditions tested. Differences in follicle morphology were evident with follicles cultured in low volume conditions having significantly greater odds of being graded as morphologically normal compared to other conditions. Furthermore, culture in a low volume of αMEM resulted in the highest proportion of morphologically normal primary and multilayer follicles (23.8% compared to 6.3-19.9% depending on condition). We, therefore, recommend culturing cryopreserved human ovarian tissue in a low volume of αMEM to support follicle health and development.

Fixation in Form-Acetic allows hyaluronic acid detection in mouse ovaries

To visualise tissues to determine the presence of disease or simply to understand anatomy, it is important to preserve fresh tissue. Fixatives are chemical solutions that preserve tissues to enable microscopic evaluation. However, some fixatives introduce artefact such as shrinkage of cells. Recently, a new fixative, Form-Acetic, was developed that is superior for preserving the structure of ovary tissue and allows investigation of ovary composition. One component of the ovary is hyaluronic acid (HA), which plays a crucial role in normal ovary function and fertility. Importantly, HA is sensitive to different fixative solutions. Therefore, it is meaningful to verify whether Form-Acetic is suitable for detecting HA. In this study, adult mouse ovaries were fixed in Form-Acetic and HA was detected. All HA-containing structures in the ovary were clearly distinguished which proves that the novel fixative allows the detection of HA.

The role of mitophagy during oocyte aging in human, mouse, and Drosophila: implications for oocyte quality and mitochondrial disease

There is a worldwide trend for women to have their first pregnancy later in life. However, as oocyte quality declines with maternal aging, this trend leads to an increase in subfertility. The cellular mechanisms underlying this decline in oocyte competence are poorly understood. Oocyte mitochondria are the subcellular organelles that supply the energy that drives early embryogenesis, and thus their quality is critical for successful conception. Mitochondria contain their own DNA (mtDNA) and mutations in mtDNA cause mitochondrial diseases with severe symptoms, such as neurodegeneration and heart disease. Since mitochondrial function declines in tissues as humans age accompanied by an accumulation of mtDNA mutations, mtDNA is implicated as a cause of declining oocyte quality in older mothers. While this mutation load could be caused by declining accuracy of the mitochondrial replisome, age-related decline in mitochondrial quality control likely contributes, however knowledge is lacking. Mitophagy, a cellular process which specifically targets and recycles damaged mitochondria may be involved, but studies are scarce. And although assisted reproductive technologies can help older mothers, how these techniques affect the mechanisms that regulate mitochondrial and oocyte quality have not been studied. With the long-term goal of understanding the molecular mechanisms that control mitochondrial quality in the oocyte, model systems including Drosophila and mouse as well as human oocytes have been used. In this review, we explore the contribution of mitophagy to oocyte quality and the need for further systematic investigation in oocytes during maternal aging using different systems.

Improved preservation of ovarian tissue morphology that is compatible with antigen detection using a fixative mixture of formalin and acetic acid

STUDY QUESTION

Can ovarian tissue morphology be better preserved whilst enabling histological molecular analyses following fixation with a novel fixative, neutral buffered formalin (NBF) with 5% acetic acid (referred to hereafter as Form-Acetic)?

SUMMARY ANSWER

Fixation with Form-Acetic improved ovarian tissue histology compared to NBF in multiple species while still enabling histological molecular analyses.

WHAT IS KNOWN ALREADY

NBF fixation results in tissue shrinkage in various tissue types including the ovary. Components of ovarian tissue, notably follicles, are particularly susceptible to NBF-induced morphological alterations and can lead to data misrepresentation. Bouin’s solution (which contains 5% acetic acid) better preserves tissue architecture compared to NBF but is limited for immunohistochemical analyses.

STUDY DESIGN, SIZE, DURATION

A comparison of routinely used fixatives, NBF and Bouin’s, and a new fixative, Form-Acetic was carried out. Ovarian tissue was used from three different species: human (n = 5 patients), sheep (n = 3; 6 ovaries; 3 animals per condition) and mouse (n = 14 mice; 3 ovaries from 3 different animals per condition).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian tissue from humans (aged 13 weeks to 32 years), sheep (reproductively young i.e. 3–6 months) and mice (10 weeks old) were obtained and fixed in 2 ml NBF, Bouin’s or Form-Acetic for 4, 8, and 24 h at room temperature. Tissues were embedded and sectioned. Five-micron sections were stained with haemotoxylin and eosin (H&E) and the percentage of artefact (clear space as a result of shrinkage) between ovarian structures was calculated. Additional histological staining using Periodic acid-Schiff and Masson’s trichrome were performed on 8 and 24 h NBF, Bouin’s and Form-Acetic fixed samples to assess the compatibility of the new fixative with stains. On ovarian tissue fixed for both 8 and 24 h in NBF and Form-Acetic, immunohistochemistry (IHC) studies to detect FOXO3a, FoxL2, collagen IV, laminin and anti-Müllerian hormone (AMH) proteins were performed in addition to the terminal deoxynucleotidyl transferase nick end labelling (TUNEL) assay to determine the compatibility of Form-Acetic fixation with types of histological molecular analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Fixation in Form-Acetic improved ovarian tissue morphology compared to NBF from all three species and either slightly improved or was comparable to Bouin’s for human, mouse and sheep tissues. Form-Acetic was compatible with H&E, Periodic acid-Schiff and Masson’s trichrome staining and all proteins (FOXO3a, FoxL2, collagen IV and laminin and AMH) could be detected via IHC. Furthermore, Form-Acetic, unlike NBF, enabled antigen recognition for most of the proteins tested without the need for antigen retrieval. Form-Acetic also enabled the detection of damaged DNA via the TUNEL assay using fluorescence.

LARGE SCALE DATA

N/A

LIMITATIONS, REASONS FOR CAUTION

In this study, IHC analysis was performed on a select number of protein types in ovarian tissue thus encouraging further studies to confirm the use of Form-Acetic in enabling the detection of a wider range of protein forms in addition to other tissue types.

WIDER IMPLICATIONS OF THE FINDINGS

The simplicity in preparation of Form-Acetic and its superior preservative properties whilst enabling forms of histological molecular analyses make it a highly valuable tool for studying ovarian tissue. We, therefore, recommend that Form-Acetic replaces currently used fixatives and encourage others to introduce it into their research workflow.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Oxford Medical Research Council Doctoral Training Programme (Oxford MRC-DTP) grant awarded to B.D.B. (Grant no. MR/N013468/1), the Fondation Hoffmann supporting R.A. and the Petroleum Technology Development Fund (PTDF) awarded to B.V.A.

Characterizing patients initiating abaloparatide, teriparatide, or denosumab in a real-world setting: a US linked claims and EMR database analysis

We characterized patients initiating abaloparatide (ABL), teriparatide (TPTD), or denosumab (DMAB) in a real-world clinical setting from a large medical and pharmacy claims database. Differences were noted in sex, age, pathologic fractures, comorbidity index, and prior bisphosphonate use for patients initiating ABL and TPTD compared with those receiving DMAB.

INTRODUCTION

To characterize patients initiating abaloparatide (ABL), teriparatide (TPTD), or denosumab (DMAB) treatment in a real-world clinical setting.

METHODS

Patients aged ≥ 18 years initiating ABL, TPTD, or DMAB between May 1, 2017, and September 24, 2018 (without receiving the same drug in the previous 12 months), were identified using the OM1 Data Cloud, which contains medical and pharmacy claims from approximately 200 million US patients. The index date was the date of initial prescription or dispensing for ABL, TPTD, or DMAB during the study period.

RESULTS

During the study period, 2666 patients initiated ABL, 9210 TPTD, and 116,718 DMAB. Mean age (standard deviation) was 69.2 (10.6) years for the ABL cohort, 68.6 (11.3) for TPTD, and 72.1 (10.2) for DMAB (P < 0.001; ABL vs DMAB). Proportionally more patients initiating ABL were female (95.2% ABL, 86.9% TPTD, and 91.3% DMAB, P < 0.001 ABL vs TPTD or DMAB). Nearly twice as many patients initiating ABL (19.1%) and TPTD (18.8%) had a previous pathologic/fragility fracture vs DMAB (9.6%; P < 0.001 ABL vs DMAB). Fewer patients initiating ABL (36.3%) or TPTD (39.7%) had Charlson comorbidity index of ≥ 2 vs DMAB (48.4%; P < 0.001 ABL vs DMAB). Before initiating ABL, TPTD, or DMAB, 44.3%, 33.8%, and 33.9% of patients had prior osteoporosis treatment, respectively. Bisphosphonate use was more common before initiating ABL (19.2%) or TPTD (19.6%), than before initiating DMAB (16.6%; P < 0.001 ABL vs DMAB).

CONCLUSIONS

Patients initiating ABL and TPTD differed in sex, age, pathologic fractures, comorbidity index, and prior bisphosphonate use compared with those initiating DMAB.

Osteoporotic fracture trends in a population of US managed care enrollees from 2007 to 2017

This study expands on previous findings that hip fracture rates may no longer be declining. We found that age- and sex-adjusted fracture rates in the US plateaued or increased through mid-2017 in a population of commercially insured and Medicare Advantage health plan enrollees, in contrast to a decline from 2007 to 2013.

INTRODUCTION

The purpose of this study was to evaluate fracture trends in US commercial and Medicare Advantage health plan members aged ≥ 50 years between 2007 and 2017.

METHODS

Retrospective analysis of the Optum Research Database from January 1, 2007, to May 31, 2017.

RESULTS

Of 1,841,263 patients identified with an index fracture, 930,690 were case-qualifying and included in this analysis. The overall age- and sex-adjusted fracture rate decreased from 14.67/1000 person-years (py) in 2007 to 11.79/1000 py in 2013, followed by a plateau for the next 3 years and then an increase to 12.50/1000 py in mid-2017. In females aged ≥ 65 years, fracture rates declined from 27.49/1000 py in 2007 to 22.08/1000 py in 2013, then increased to 24.92/1000 py in mid-2017. Likewise, fracture rates in males aged ≥ 65 years declined from 2007 (12.00/1000 py) to 2013 (10.72/1000 py), then increased to 12.04/1000 py in mid-2017. The age- and sex-adjusted fracture rates for most fracture sites declined from 2007 to 2013 by 3.7% per year (P = 0.310).

CONCLUSIONS

Following a consistent decline in fracture rate from 2007 to 2013, trends from 2014 to 2017 indicate fracture rates are no longer declining and, for some fracture types, rates are rising.

Establishing reproductive potential and advances in fertility preservation techniques for XY individuals with differences in sex development

BACKGROUND

Discordance between gonadal type and gender identity has often led to an assumption of infertility in patients with differences in sex development (DSD). However, there is now greater recognition of fertility being an important issue for this group of patients. Currently, gonadal tissue that may have fertility potential is not being stored for individuals with DSD and, where gonadectomy forms part of management, is often discarded. The area of fertility preservation has been predominantly driven by oncofertility which is a field dedicated to preserving the fertility of patients undergoing gonadotoxic cancer treatment. The use of fertility preservation techniques could be expanded to include individuals with DSD where functioning gonads are present.

METHODS

This is a systematic literature review evaluating original research articles and relevant reviews between 1974 and 2018 addressing DSD and fertility, in vitro maturation of sperm, and histological/ultrastructural assessment of gonadal tissue in complete and partial androgen insensitivity syndrome, 17β-hydroxysteroid dehydrogenase type 3 and 5α-reductase deficiency.

CONCLUSION

Successful clinical outcomes of ovarian tissue cryopreservation are paving the way for similar research being conducted using testicular tissue and sperm. There have been promising results from both animal and human studies leading to cryopreservation of testicular tissue now being offered to boys prior to cancer treatment. Although data are limited, there is evidence to suggest the presence of reproductive potential in the gonads of some individuals with DSD. Larger, more detailed studies are required, but if these continue to be encouraging, individuals with DSD should be given the same information, opportunities and access to fertility preservation as other patient groups.

Abaloparatide for risk reduction of nonvertebral and vertebral fractures in postmenopausal women with osteoporosis: a network meta-analysis

This network meta-analysis assessed the efficacy of abaloparatide versus other treatment options to reduce the risk of fractures in women with postmenopausal osteoporosis. The analysis indicates that abaloparatide reduces the risk of fractures in women with postmenopausal osteoporosis versus placebo and compared with other treatment options.

INTRODUCTION

This network meta-analysis (NMA) assessed the relative efficacy of abaloparatide versus other treatments to reduce the risk of fractures in women with postmenopausal osteoporosis (PMO).

METHODS

PubMed®, Embase®, and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published before December 20, 2017, that included women with PMO who were eligible to receive interventions for primary or secondary fracture prevention. The NMA was conducted by fracture site (vertebral [VF], nonvertebral [NVF], and wrist), with the relative risk (RR) of fracture versus placebo the main clinical endpoint. The NMA used fixed-effects and random-effects approaches.

RESULTS

A total of 4978 articles were screened, of which 22 were included in the analysis. Compared with other treatments, abaloparatide demonstrated the greatest treatment effect relative to placebo in the VF network (RR = 0.13; 95% credible interval [CrI] 0.04-0.34), the NVF network (RR = 0.50; 95% CrI 0.28-0.85), and the wrist fracture network (RR = 0.39; CrI 0.15-0.90). Treatment ranking showed that abaloparatide had the highest estimated probability of preventing fractures in each of the networks (79% for VF, 70% for NVF, and 53% for wrist fracture) compared with other treatments. Individual networks demonstrated a good level of agreement with direct trial evidence and direct pair-wise comparisons.

CONCLUSIONS

This NMA indicates that abaloparatide reduces the RR of VF, NVF, and wrist fracture in women with PMO with or without prior fracture versus placebo, compared with other treatment options. Limitations include that adverse events and drug costs were not considered, and that generalizability is limited to the trial populations and endpoints included in the NMA.

Variation in follicle health and development in cultured cryopreserved ovarian cortical tissue: a study of ovarian tissue from patients undergoing fertility preservation

This study investigated how follicle health and development in human ovarian tissue cryopreserved for fertility preservation varied between patients before and after 6 d of in vitro culture. Ovarian tissue from 12 patients (9-25 years) was used. In 3 patients, a 1hr neutral red (NR) incubation was used to identify tissues with viable follicles. Tissues were fixed, sectioned and follicles staged and graded for health. Inter-patient differences were observed in the non-cultured tissue in the number of both healthy follicles (p = 0.005) and growing follicles (p = 0.005). After culture there was significant variation in the number of transitional, primary and secondary follicles between patients (p < 0.001). Asymmetric primary follicles with a single complete layer of granulosa cells plus two or more additional partial layers were 5.5 times more likely to be observed in cultured compared to non-cultured tissue (p = 0.0063). Non-cultured (p = 0.0125) and cultured (p < 0.001) tissue selected using NR had more healthy follicles compared to tissue not selected using NR. Non-cultured and cultured tissue selected using NR had more healthy follicles compared to tissue not selected using NR (p = 0.0125; p < 0.001). We demonstrate that inter-patient variation exists in the health and development of follicles before and after culture. Culture systems need to be optimized to support cryopreserved ovarian tissue and these findings should prompt researchers to consider patient variation when evaluating culture systems.

In vitro and in vivo mouse follicle development in ovaries and reaggregated ovaries

Follicle development requires complex and coordinated interactions between both the oocyte and its associated somatic cells. In ovarian dysfunction, follicle development may be abnormal due to defective somatic cell function; for example, premature ovarian insufficiency or malignancies. Replacing defective somatic cells, using the reaggregated ovary (RO) technique, may 'rescue' follicle development. ROs containing mature follicles have been generated when transplanted to a host mouse to develop. We have developed a RO culture technique and the aims were to determine how follicle development differed between transplanted and cultured ROs, and the influence of ovarian age (P2 vs P6). Mouse ROs were cultured for 14 days; P2 and P6 ovaries cultured as Controls. Follicle development was compared to ROs transplanted for 14 days and ovaries from P16 and P20 mice. ROs generated from either P2 or P6 exhibited similar follicle development in culture whereas in vivo follicle development was more advanced in P6 ROs. Follicles were more developed in cultured ROs than transplanted ROs. However, follicles in cultured ROs and ovaries had smaller oocytes with fewer theca and granulosa cells than in vivo counterparts. Our results demonstrate the fluidity of follicle development despite ovary dissociation and that environment is more important to basal lamina formation and theca cell development. Furthermore, follicle development within cultured ROs appears to be independent of oocyte nest breakdown and primordial follicle formation in source ovaries. Our results highlight the need for understanding follicle development in vitro, particularly in the development of the RO technique as a potential fertility treatment.

Oocyte-specific ablation of N- and O-glycans alters cumulus cell signalling and extracellular matrix composition

Cumulus-oocyte complex (COC) expansion is essential for ovulation and fertilisation and is linked to oocyte quality. Hyaluronan (HA), the major matrix constituent, is cross-linked via inter-α-inhibitor heavy chains (HCs), pentraxin 3 (PTX3) and tumour necrosis factor-stimulated gene 6 (TSG-6). All except HCs are secreted by cumulus cells in response to oocyte-secreted factors, which signal via SMAD pathways. The double mutant (DM) mouse generates oocytes lacking complex N- and O-glycans due to oocyte-specific deletion of core 1 β1,3-galactosyltransferase (C1galt1) and N-acetylglucosaminyltransferase I (Mgat1) and has modified cumulus expansion. We compared COCs before expansion (48 h-post-pregnant mare serum gonadotrophin (PMSG)) and at late-stage expansion (9 h-post-human chorionic gonadotrophin (hCG); control n=3 mice, DM n=3 per group). Using histochemistry the levels of HA, HCs, PTX3, TSG-6 and phosphorylated-SMAD1/5/8 and -SMAD2 (12-25 COCs per group) were assessed. DM COCs did not differ from Controls in cumulus size or cell density at 9 h-post-hCG; however, HA and HC levels and phosphorylated-SMAD1/5/8 were reduced. Furthermore, no correlations were found between the levels of matrix molecules and cumulus area in DM or Control samples. These data suggest that HA and HCs can support cumulus expansion provided that they are present above minimum threshold levels. We propose that oocyte-specific ablation of C1galt1 and Mgat1 may affect bone morphogenetic protein 15 synthesis or bioactivity, thereby reducing SMAD1/5/8 phosphorylation and HA production.

Validating the RedMIT/GFP-LC3 Mouse Model by Studying Mitophagy in Autosomal Dominant Optic Atrophy Due to the OPA1Q285STOP Mutation

Background: Autosomal dominant optic atrophy (ADOA) is usually caused by mutations in the essential gene, OPA1. This encodes a ubiquitous protein involved in mitochondrial dynamics, hence tissue specificity is not understood. Dysregulated mitophagy (mitochondria recycling) is implicated in ADOA, being increased in OPA1 patient fibroblasts. Furthermore, autophagy may be increased in retinal ganglion cells (RGCs) of the OPA1Q285STOP mouse model. Aims: We developed a mouse model for studying mitochondrial dynamics in order to investigate mitophagy in ADOA. Methods: We crossed the OPA1Q285STOP mouse with our RedMIT/GFP-LC3 mouse, harboring red fluorescent mitochondria and green fluorescent autophagosomes. Colocalization between mitochondria and autophagosomes, the hallmark of mitophagy, was quantified in fluorescently labeled organelles in primary cell cultures, using two high throughput imaging methods Imagestream (Amnis) and IN Cell Analyzer 1000 (GE Healthcare Life Sciences). We studied colocalization between mitochondria and autophagosomes in fixed sections using confocal microscopy. Results: We validated our imaging methods for RedMIT/GFP-LC3 mouse cells, showing that colocalization of red fluorescent mitochondria and green fluorescent autophagosomes is a useful indicator of mitophagy. We showed that colocalization increases when lysosomal processing is impaired. Further, colocalization of mitochondrial fragments and autophagosomes is increased in cultures from the OPA1Q285STOP/RedMIT/GFP-LC3 mice compared to RedMIT/GFP-LC3 control mouse cells that were wild type for OPA1. This was apparent in both mouse embryonic fibroblasts (MEFs) using IN Cell 1000 and in splenocytes using ImageStream imaging flow cytometer (Amnis). We confirmed that this represents increased mitophagic flux using lysosomal inhibitors. We also used microscopy to investigate the level of mitophagy in the retina from the OPA1Q285STOP/RedMIT/GFP-LC3 mice and the RedMIT/GFP-LC3 control mice. However, the expression levels of fluorescent proteins and the image signal-to-background ratios precluded the detection of colocalization so we were unable to show any difference in colocalization between these mice. Conclusions: We show that colocalization of fluorescent mitochondria and autophagosomes in cell cultures, but not fixed tissues from the RedMIT/GFP-LC3, can be used to detect mitophagy. We used this model to confirm that mitophagy is increased in a mouse model of ADOA. It will be useful for cell based studies of diseases caused by impaired mitochondrial dynamics.

Oocyte stem cells: fact or fantasy?

For many decades, the dogma prevailed that female mammals had a finite pool of oocytes at birth and this was gradually exhausted during a lifetime of reproductive function. However, in 2004, a new era began in the field of female oogenesis. A study was published that appeared to detect oocyte-stem cells capable of generating new eggs within mouse ovaries. This study was highly controversial and the years since this initial finding have produced extensive research and even more extensive debate into their possibility. Unequivocal evidence testifying to the existence of oocyte-stem cells (OSCs) has yet to be produced, meanwhile the spectrum of views from both sides of the debate are wide-ranging and surprisingly passionate. Although recent studies have presented some convincing results that germ cells exist and are capable of creating new oocytes, many questions remain. Are these cells present in humans? Do they exist in physiological conditions in a dormant state? This comprehensive review first examines where and how the dogma of a finite pool was established, how this has been challenged over the years and addresses the most pertinent questions as to the current status of their existence, their role in female fertility, and perhaps most importantly, if they do exist, how can we harness these cells to improve a woman's oocyte reserve and treat conditions such as premature ovarian insufficiency (POI: also known as premature ovarian failure, POF).

Outcome of nutritional screening in the acute paediatric setting

INTRODUCTION

Multiple nutritional risk assessment tools are available, but there are limited data on their application in the acute setting. We explored the validity of two tools in a tertiary Children's Hospital's acute unit and the cohort's nutritional status using WHO definitions.

METHODS

Prospective study n=300 (median 38 months; 44.6% female; 25.7% ≤12 months). Participants had standard anthropometry measured, all were screened using the Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), the Paediatric Malnutrition Screening Tool (PMST) (modified STAMP) and 125 were additionally screened using the Paediatric Yorkhill Malnutrition Screening (PYMS) tool.

RESULTS

The percentages with medium/high nutritional risk were as follows: STAMP 73.1%, PMST 79.3% and PYMS 30%. Height/weight were normally distributed with: 3.4% stunted (height-for-age z-score <-2); aged ≤ 5 years, 6.8% wasted (weight-for-height z-score (WHZ) <-2), 17.9% overweight (WHZ 1-2) and 6.2% obese (WHZ >2); aged >5 years, 5.8% thin (body mass index (BMI)-z-score (BAZ) <-2), 17.3% overweight (BAZ 1-2) and 5.8% obese (BAZ >2). The tools showed poor specificity and variable sensitivities when compared with WHO malnutrition criteria, with positive predictive values of <50%. κ-Analysis also showed poor agreement between the tools and the WHO cut-offs.

CONCLUSION

These results suggest that nutritional screening tools have poor sensitivity and are difficult to interpret in the acute setting. It may be more effective to include the assessment of weight and height and nutritional intake in the context of the acute presentation as part of routine clinical assessment rather than relying on screening tools to identify those at risk.

Analysis of in vitro follicle development during the onset of premature ovarian insufficiency in a mouse model

Premature ovarian insufficiency (POI) occurs in 1% of women under 40 years of age and is predominantly idiopathic. In a transgenic mouse model of follicular POI, the Double Mutant (DM), female mice are fertile at 6 weeks of age, become infertile by 9 weeks and exhibit POI by 3 months. DM female mice generate oocytes lacking mucin O-glycans and complex N-glycans due to deletion of core 1 synthase, glycoprotein-N-acetylgalactosamine 3-β-galactosyltransferase 1 (C1galt1) and mannoside acetylglucosaminyltransferase 1 (Mgat1) respectively (DM, C1galt1^F/FMgat1^F/F:ZP3Cre; Control, C1galt1^F/FMgat1^F/F). To determine whether DM follicle development could be improved in a controlled environment, follicles from DM and Control mice were cultured individually and follicle growth, morphology, survival and antrum formation were evaluated. DM ovaries were more rigid than Control ovaries at 3, 6 and 9 weeks, which was exacerbated with age, resulting in a failure to isolate follicles from 9 week-old DM females. DM follicles had decreased survival compared with Control follicles from females at 3 and 6 weeks of age. Furthermore, survival rate of DM follicles decreased with age between 3 and 6 weeks. DM follicles at both 3 and 6 weeks had accelerated follicle growth and altered antrum formation during the first few days of culture but, after 6 days, follicles were equivalent in size to the Controls. In conclusion, a population of DM follicles retain the potential to develop in vitro, and therefore follicle culture offers a reliable method to generate antral follicles from preantral follicles after the onset of POI in these female mice.

Dysregulation of follicle development in a mouse model of premature ovarian insufficiency

Premature ovarian insufficiency (POI) occurs in 1% of reproductive-age women. The ovarian manifestation ranges from the presence of a variable population of follicles (follicular) to the absence of follicles (afollicular), and in the majority of cases the cause is unknown. A transgenic mouse model of follicular POI, the Double Mutant (DM), arises from oocyte-specific deletion of Mgat1 and C1galt1 required for the generation of O- and N-glycans. DM females are subfertile at 6 weeks, infertile by 9 weeks and exhibit POI by 12 weeks of age. In this study we investigate the cause of the reduced fertility at 6 weeks and infertility at 9 weeks of DM females. Ovary sections were used to analyse follicle and corpora lutea (CL) numbers, apoptosis, and levels of laminin and 3β-hydroxysteroid dehydrogenase using immunohistochemistry. After POI, DM females unexpectedly remained sexually receptive. At both 6 and 9 weeks, DM ovaries contained more primary follicles, however, at 9 weeks DM follicles were proportionally healthier, revealed by TUNEL analysis compared with Controls. In 9 week DM ovaries (collected post-mating), secondary follicles had theca and basal lamina structure abnormalities, whilst preovulatory follicles failed to ovulate resulting in the presence of numerous luteinised unruptured follicles, indicative of ovulation failure. Finally, DM ovaries contained more regressing CL with decreased luteal cell apoptosis indicative of a defect in CL regression. Identifying these follicular modifications have provided insight into the aetiology of a model of POI and highlight targets to investigate with the hope of developing new fertility treatments.

Chromosome Cohesion Established by Rec8-Cohesin in Fetal Oocytes Is Maintained without Detectable Turnover in Oocytes Arrested for Months in Mice

Sister chromatid cohesion mediated by the cohesin complex is essential for chromosome segregation in mitosis and meiosis [1]. Rec8-containing cohesin, bound to Smc3/Smc1α or Smc3/Smc1β, maintains bivalent cohesion in mammalian meiosis [2-6]. In females, meiotic DNA replication and recombination occur in fetal oocytes. After birth, oocytes arrest at the prolonged dictyate stage until recruited to grow into mature oocytes that divide at ovulation. How cohesion is maintained in arrested oocytes remains a pivotal question relevant to maternal age-related aneuploidy. Hypothetically, cohesin turnover regenerates cohesion in oocytes. Evidence for post-replicative cohesion establishment mechanism exists, in yeast and invertebrates [7, 8]. In mouse fetal oocytes, cohesin loading factor Nipbl/Scc2 localizes to chromosome axes during recombination [9, 10]. Alternatively, cohesion is maintained without turnover. Consistent with this, cohesion maintenance does not require Smc1β transcription, but unlike Rec8, Smc1β is not required for establishing bivalent cohesion [11, 12]. Rec8 maintains cohesion without turnover during weeks of oocyte growth [3]. Whether the same applies to months or decades of arrest is unknown. Here, we test whether Rec8 activated in arrested mouse oocytes builds cohesion revealed by TEV cleavage and live-cell imaging. Rec8 establishes cohesion when activated during DNA replication in fetal oocytes using tamoxifen-inducible Cre. In contrast, no new cohesion is detected when Rec8 is activated in arrested oocytes by tamoxifen despite cohesin synthesis. We conclude that cohesion established in fetal oocytes is maintained for months without detectable turnover in dictyate-arrested oocytes. This implies that women's fertility depends on the longevity of cohesin proteins that established cohesion in utero.

Molecular analysis of the cumulus matrix: insights from mice with O-glycan-deficient oocytes

During follicle development, oocytes secrete factors that influence the development of granulosa and cumulus cells (CCs). In response to oocyte and somatic cell signals, CCs produce extracellular matrix (ECM) molecules resulting in cumulus expansion, which is essential for ovulation, fertilisation, and is predictive of oocyte quality. The cumulus ECM is largely made up of hyaluronan (HA), TNF-stimulated gene-6 (TSG-6, also known as TNFAIP6), pentraxin-3 (PTX3), and the heavy chains (HCs) of serum-derived inter-α-inhibitor proteins. In contrast to other in vivo models where modified expansion impairs fertility, the cumulus mass of C1galt1 Mutants, which have oocyte-specific deletion of core 1-derived O-glycans, is modified without impairing fertility. In this report, we used C1galt1 Mutant (C1galt1^FF:ZP3Cre) and Control (C1galt1^FF) mice to investigate how cumulus expansion is affected by oocyte-specific deletion of core 1-derived O-glycans without adversely affecting oocyte quality. Mutant cumulus–oocyte complexes (COCs) are smaller than Controls, with fewer CCs. Interestingly, the CCs in Mutant mice are functionally normal as each cell produced normal levels of the ECM molecules HA, TSG-6, and PTX3. However, HC levels were elevated in Mutant COCs. These data reveal that oocyte glycoproteins carrying core 1-derived O-glycans have a regulatory role in COC development. In addition, our study of Controls indicates that a functional COC can form provided all essential components are present above a minimum threshold level, and thus some variation in ECM composition does not adversely affect oocyte development, ovulation or fertilisation. These data have important implications for IVF and the use of cumulus expansion as a criterion for oocyte assessment.

Oocyte-derived Smad4 is not required for development of the oocyte or the preimplantation embryo

The generation of a competent egg requires complex molecular interactions between the oocyte and the ovary, and transforming growth factor β (TGF-β) is a major signaling pathway. Smad4 is a central regulator of the TGF-β signaling pathway as it mediates gene expression triggered by activation of TGF-β receptors. Deletion of Smad4 in granulosa cells disrupts follicle development; however, the role of Smad4 in the oocyte has not been confirmed. Furthermore, the role of Smad4 in embryo development has not been confirmed because previous studies of Smad4(del/del) embryos were generated from heterozygous parents, and thus it is possible that maternal transcripts rescue development before embryonic day 6.5 (E6.5) when Smad4(del/del) embryos die. To determine the role of TGF-β signaling in oocyte and embryo development, mice with oocyte-specific deletion of Smad4 were studied. Fertility was evaluated in Mutant (Smad4(F/F):ZP3Cre) and CONTROL (Smad4(F/F)) females mated continuously with control males during a 6-month period. Surprisingly, Mutant females were fertile with the same litter size (Mutants, 9.23 ± 0.4; CONTROLs, 9.42 ± 0.4) and interlitter period as CONTROLs. Ovulation rate induced using a superovulation regime did not differ between CONTROLs and Mutants at both 6 weeks and 6 months. Embryo development was assessed at E6.5 using CONTROL and Mutant females mated with heterozygous males. Development of Smad4(del/del) embryos at E6.5 was retarded consistent with previous studies of embryos generated from heterozygous parents indicating that there is no rescue of preimplantation development by maternal transcripts. The numbers of implanted embryos at 6.5 dpc also did not differ (

CONTROL

9.1 ± 0.4; Mutant: 7.0 ± 0.9). However, only 26.3% of E6.5 embryos carried by Mutant females were Smad4(del/del) compared with the expected ratio of 50%. Since litter size was not decreased, this indicates that either the number of Smad4(del) sperm fertilizing the oocytes is reduced or implantation of Smad4(del/del) embryos is suboptimal. In summary, we have shown that Smad4 in the oocyte, and thus TGF-β signaling, is not required for oocyte or follicle development, ovulation, fertilization, preimplantation development, or implantation.

Oocytes lacking O-glycans alter follicle development and increase fertility by increasing follicle FSH sensitivity, decreasing apoptosis, and modifying GDF9:BMP15 expression

The number of eggs ovulated varies within and between species and is influenced by many variables. However, the regulatory mechanisms remain poorly understood. We previously demonstrated a key role for the oocyte because mice generating oocytes deficient in core 1-derived O-glycans ovulate ∼40-50% more eggs than Controls. Here we analyze the basis of this phenotype using Mutant [core 1 β1,3-galactosyltransferase 1 (C1galt1)(FF):zona pellucida glycoprotein 3 Cre (ZP3Cre)] and Control (C1galt1(FF)) female mice. In culture, Mutant follicles exhibited delayed antrum formation [indicative of follicle stimulant hormone (FSH) dependence] and increased sensitivity to FSH. Although the Mutant estrous cycle was extended, comprehensive endocrine changes were not observed; rather FSH, LH, inhibin B, and anti-Mullerian hormone were temporally altered, revealing estrous cycle stage-specific modifications to the hypothalamic-pituitary-gonadal axis. At proestrus, when FSH levels were decreased in Mutants, ovaries contained more, smaller, preantral follicles. Mutant follicles exhibited reduced levels of apoptosis, and both B-cell lymphoma 2 (Bcl-2) and BCL-2-associated X protein (Bax) were altered compared with Controls. Mutant ovaries also had an increase in the expression ratio of growth differentiation factor 9 (GDF9):bone morphogenetic protein 15 (BMP15) at diestrus. On the basis of these data, we propose that modified oocyte glycoproteins alter GDF9:BMP15 expression modifying follicle development resulting in the generation of more follicles. Thus, the oocyte is a key regulator of follicle development and has a crucial role in determining ovulation rate.

A TaqMan-based multiplex real-time PCR assay for the simultaneous detection of Wuchereria bancrofti and Brugia malayi

With the Global Program for the Elimination of Lymphatic Filariasis continuing to make strides towards disease eradication, many locations endemic for the causative parasites of lymphatic filariasis are realizing a substantial decrease in levels of infection and rates of disease transmission. However, with measures of disease continuing to decline, the need for time-saving and economical molecular diagnostic assays capable of detecting low levels of parasite presence is increasing. This need is greatest in locations co-endemic for both Wuchereria bancrofti and Brugia parasites because testing for both causative agents individually results in significant increases in labor and reagent costs. Here we describe a multiplex, TaqMan-based, real-time PCR assay capable of simultaneously detecting W. bancrofti and Brugia malayi DNA extracted from human bloodspots or vector mosquito pools. With comparable sensitivity to established singleplex assays, this assay provides significant cost and labor savings for disease monitoring efforts in co-endemic locations.

Tug of war in the haematopoietic stem cell niche: do myeloma plasma cells compete for the HSC niche?

In the adult mammal, normal haematopoiesis occurs predominantly in the bone marrow, where primitive haematopoietic stem cells (HSC) and their progeny reside in specialised microenvironments. The bone marrow microenvironment contains specific anatomical areas (termed niches) that are highly specialised for the development of certain blood cell types, for example HSCs. The HSC niche provides important cell–cell interactions and signalling molecules that regulate HSC self-renewal and differentiation processes. These same signals and interactions are also important in the progression of haematological malignancies, such as multiple myeloma (MM). This review provides an overview of the bone marrow microenvironment and its involvement in normal, physiological HSC maintenance and plasma cell growth throughout MM disease progression.

Embryos generated from oocytes lacking complex N- and O-glycans have compromised development and implantation

Female mice generating oocytes lacking complex N- and O-glycans (double mutants (DM)) produce only one small litter before undergoing premature ovarian failure (POF) by 3 months. Here we investigate the basis of the small litter by evaluating ovulation rate and embryo development in DM (Mgat1(F/F)C1galt1(F/F):ZP3Cre) and Control (Mgat1(F/F)C1galt1(F/F)) females. Surprisingly, DM ovulation rate was normal at 6 weeks, but declined dramatically by 9 weeks. In vitro development of zygotes to blastocysts was equivalent to Controls although all embryos from DM females lacked a normal zona pellucida (ZP) and ∼30% lacked a ZP entirely. In contrast, in vivo preimplantation development resulted in less embryos recovered from DM females compared with Controls at 3.5 days post coitum (dpc) (3.2±1.3 vs 7.0±0.6). Furthermore, only 45% of mated DM females contained embryos at 3.5 dpc. Of the preimplantation embryos collected from DM females, approximately half were morulae unlike Controls where the majority were blastocysts, indicating delayed embryo development in DM females. Post-implantation development in DM females was analysed to determine whether delayed preimplantation development affected subsequent development. In DM females at 5.5 dpc, only ∼40% of embryos found at 3.5 dpc had implanted. However, at 6.5 dpc, implantation sites in DM females corresponded to embryo numbers at 3.5 dpc indicating delayed implantation. At 9.5 dpc, the number of decidua corresponded to embryo numbers 6 days earlier indicating that all implanted embryos progress to midgestation. Therefore, a lack of complex N- and O-glycans in oocytes during development impairs early embryo development and viability in vivo leading to delayed implantation and a small litter.

Complex N-glycans are essential, but core 1 and 2 mucin O-glycans, O-fucose glycans, and NOTCH1 are dispensable, for mammalian spermatogenesis

To identify roles in spermatogenesis for major subclasses of N- and O-glycans and Notch signaling, male mice carrying floxed C1galt1, Pofut1, Notch1 or Mgat1 alleles and a testis-specific Cre recombinase transgene were generated. T-synthase (C1GALT1) transfers Gal to generate core 1 and core 2 mucin O-glycans; POFUT1 transfers O-fucose to particular epidermal growth factor-like repeats and is essential for canonical Notch signaling; and MGAT1 (GlcNAcT-I) transfers GlcNAc to initiate hybrid and complex N-glycan synthesis. Cre recombinase transgenes driven by various promoters were investigated, including Stra8-iCre expressed in spermatogonia, Sycp1-Cre expressed in spermatocytes, Prm1-Cre expressed in spermatids, and AMH-Cre expressed in Sertoli cells. All Cre transgenes deleted floxed alleles, but efficiencies varied widely. Stra8-iCre was the most effective, deleting floxed Notch1 and Mgat1 alleles with 100% efficiency and floxed C1galt1 and Pofut1 alleles with ~80% efficiency, based on transmission of deleted alleles. Removal of C1galt1, Pofut1, or Notch1 in spermatogonia had no effect on testicular weight, histology, or fertility. However, males in which the synthesis of complex N-glycans was blocked by deletion of Mgat1 in spermatogonia did not produce sperm. Spermatogonia, spermatocytes, and spermatids were generated, but most spermatids formed giant multinucleated cells or symplasts, and apoptosis was increased. Therefore, although core 1 and 2 mucin O-glycans, NOTCH1, POFUT1, O-fucose glycans, and Notch signaling are dispensable, MGAT1 and complex N-glycans are essential for spermatogenesis.

Premature ovarian failure in mice with oocytes lacking core 1-derived O-glycans and complex N-glycans

Premature ovarian failure (POF) affects up to 1.4% of women under the age of 40 yr and less than 30% of cases have a known cause. Here we describe a new mouse model of POF resulting from oocyte-specific ablation of core 1-derived (mucin) O-glycans and complex and hybrid N-glycans. Females carrying floxed alleles of both the C1galt1 (T-syn) and Mgat1 glycosyltransferase genes and a ZP3Cre transgene, generate oocytes lacking complex O- and N-glycans following oocyte-specific deletion at the primary follicle stage. We previously showed that few double-mutant females are fertile, and those produce only a single small litter. Here we show that ovarian function declined rapidly in double-mutant females with less than 1% ovulating at 11 wk of age after superovulation with exogenous gonadotropins. Ovary weight was significantly decreased in double-mutant females by 3 months of age, consistent with a decrease in the number of developing follicles. FSH levels in double-mutant females were elevated at 3 months of age, and testosterone and inhibin A were decreased, showing that the loss of complex N- and O-glycans from oocyte glycoproteins affected hypothalamic-pituitary-gonadal feedback loops. The absence of developing follicles, ovary dysfunction, reduced testosterone and inhibin A, and elevated FSH in double-mutant females lacking C1galt1 and Mgat1 in oocytes represents a new mouse model for the study of follicular POF.

Cloning the Gene for the Malolactic Fermentation of Wine from Lactobacillus delbrueckii in Escherichia coli and Yeasts

The gene responsible for the malolactic fermentation of wine was cloned from the bacterium Lactobacillus delbrueckii into Escherichia coli and the yeast Saccharomyces cerevisiae. This gene codes for the malolactic enzyme which catalyzes the conversion of l-malate to l-lactate. A genetically engineered yeast strain with this enzymatic capability would be of considerable value to winemakers. L. delbrueckii DNA was cloned in E. coli on the plasmid pBR322, and two E. coll clones able to convert l-malate to l-lactate were selected. Both clones contained the same 5-kilobase segment of L. delbrueckii DNA. The DNA segment was transferred to E. coli-yeast shuttle vectors, and gene expression was analyzed in both hosts by using enzymatic assays for l-lactate and l-malate. When grown nonaerobically for 5 days, E. coli cells harboring the malolactic gene converted about 10% of the l-malate in the medium to l-lactate. The best expression in S. cerevisiae was attained by transfer of the gene to a shuttle vector containing both a yeast 2-mum plasmid and yeast chromosomal origin of DNA replication. When yeast cells harboring this plasmid were grown nonaerobically for 5 days, ca. 1.0% of the l-malate present in the medium was converted to l-lactate. The L. delbrueckii controls grown under these same conditions converted about 25%. A laboratory yeast strain containing the cloned malolactic gene was used to make wine in a trial fermentation, and about 1.5% of the l-malate in the grape must was converted to l-lactate. Increased expression of the malolactic gene in wine yeast will be required for its use in winemaking. This will require an increased understanding of the factors governing the expression of this gene in yeasts.

Genetics of platelet reactivity in normal, healthy individuals

BACKGROUND

The Platelet Function Analyzer-100 (PFA-100) is widely used to measure platelet reactivity in whole blood under high shear.

OBJECTIVE

To characterize the genetic component of platelet reactivity among normal individuals, using the PFA-100.

METHODS

We compared baseline platelet reactivity with sex, age, platelet count, hematocrit, plasma von Willebrand factor antigen (VWF:Ag), and alleles of seven candidate genes: integrin subunits alpha2 (ITGA2) and beta3 (ITGB3), platelet glycoproteins GPIbalpha (GP1BA) and GPVI (GP6), purinogenic receptors (P2RY1 and P2RY12) and cyclooxygenase-1 (COX1).

RESULTS

Based on linear and logistic regression models, we report an inverse correlation between baseline closure time (CT) initiated by collagen plus epinephrine (CEPI) and plasma VWF:Ag level, ITGA2 807T and P2RY1 893C, and an inverse correlation between baseline CT initiated by collagen plus adenosine diphosphate (CADP) and P2RY1 893C or GP1BA -5C.

CONCLUSIONS

These results indicate that genetic polymorphisms in ITGA2 and P2RY1 combine with plasma VWF:Ag levels to modulate baseline platelet reactivity in response to collagen plus EPI, while genetic differences in P2RY1 and GP1BA significantly effect platelet responses to collagen plus ADP. Our results demonstrate that the PFA-100 can be used to evaluate the effects of genetic predictors of platelet function.

Oocyte-specific deletion of complex and hybrid N-glycans leads to defects in preovulatory follicle and cumulus mass development

Complex and hybrid N-glycans generated by N-acetylglucosaminyltransferase I (GlcNAcT-I), encoded by Mgat1, affect the functions of glycoproteins. We have previously shown that females with oocyte-specific deletion of a floxed Mgat1 gene using a zona pellucida protein 3 (ZP3)Cre transgene produce fewer pups primarily due to a reduction in ovulation rate. Here, we show that the ovulation rate of mutant females is decreased due to aberrant development of preovulatory follicles. After a superovulatory regime of 48 h pregnant mare's serum (PMSG) and 9 h human chorionic gonadotropin (hCG), mutant ovaries weighed less and contained approximately 60% fewer preovulatory follicles and more atretic and abnormal follicles than controls. Unlike controls, a proportion of mutant follicles underwent premature luteinization. In addition, mutant preovulatory oocytes exhibited gross abnormalities with approximately 36% being blebbed or zona-free. While 97% of wild-type oocytes had a perivitelline space at the preovulatory stage, approximately 54% of mutant oocytes did not. The cumulus mass surrounding mutant oocytes was also smaller with a decreased number of proliferating cells compared with controls, although hyaluronan around mutant oocytes was similar to controls. In addition, cumulus cells surrounding mutant eggs were resistant to removal by either hyaluronidase or incubation with capacitated sperm. Therefore, the absence of complex and hybrid N-glycans on oocyte glycoproteins leads to abnormal folliculogenesis resulting in a decreased ovulation rate.

Mouse fertility is enhanced by oocyte-specific loss of core 1-derived O-glycans

Regulation of the number of eggs ovulated by different mammalian species remains poorly understood. Here we show that oocyte-specific deletion at the primary follicle stage of core 1 beta1,3-galactosyltransferase (T-synthase; generates core 1-derived O-glycans), leads to a sustained increase in fertility. T-syn mutant females ovulated 30-50% more eggs and had a sustained increase in litter size compared to controls. Ovarian weights and follicle numbers were greater in mutants, but follicular apoptosis was not decreased. The number of follicles entering the growing pool was unaltered, but 3-wk mutants ovulated fewer eggs, suggesting that increased fertility results from prolonged follicle development. T-syn mutant ovaries also contained numerous multiple-oocyte follicles (MOFs) that appeared to form by adjacent, predominantly preantral, follicles joining--a new mechanism for MOF generation. Ovulation of multiple eggs from MOFs was not the reason for increased fertility based on ovulated egg and corpora lutea numbers. Thus, the absence of T-synthase caused modified follicular development, leading to the maturation and ovulation of more follicles, to MOF formation at late stages of folliculogenesis, and to increased fertility. These results identify novel roles for glycoproteins from the oocyte as suppressors of fertility and regulators of follicular integrity in the mouse.

Fertilization in mouse does not require terminal galactose or N-acetylglucosamine on the zona pellucida glycans

Fertilization in mammals requires sperm to bind to the zona pellucida (ZP) that surrounds the egg. Galactose (Gal) or N-acetylglucosamine (GlcNAc) residues on the glycans of ZP protein 3 (ZP3) have been implicated as mouse sperm receptors. However, Mgat1(-/-) eggs with modified N-glycans lacking terminal Gal and GlcNAc residues are fertilized. To determine if Gal and GlcNAc on O-glycans of the ZP are required for fertilization, a conditional allele of the T-synthase gene (T-syn(F)) was generated. T-syn encodes core 1 beta1,3-galactosyltransferase 1 (T-synthase), which initiates the synthesis of core-1-derived O-glycans, the only O-glycans on mouse ZP3. T-syn(F/F):ZP3Cre females in which T-syn(F) was deleted at the beginning of oogenesis generated eggs lacking core-1-derived O-glycans. Nevertheless, T-syn(F/F):ZP3Cre females were fertile and their eggs bound sperm similarly to controls. In addition, T-syn(-/-) embryos generated from T-syn null eggs developed until approximately E12.5. Thus, core-1-derived O-glycans are not required for blastogenesis, implantation, or development prior to midgestation. Moreover, T-syn(-/-)Mgat1(-/-) eggs lacking complex and hybrid N-glycans as well as core-1-derived O-glycans were fertilized. The combined data show that mouse ZP3 does not require terminal Gal or GlcNAc on either N- or O-glycans for fertilization.

Seroprevalence of dengue in Trinidad using rapid test kits: a cord blood survey

A cross-sectional sero-epidemiological study was conducted to determine the prevalence of dengue in Trinidad. Two commercial rapid test kits, PanBio Dengue Duo IgM and IgG Rapid Strip Test and the Bio-Check Plus Dengue G/M Cassette Test (Brittney) were used. The immunosorbent assay (ELISA) (FOCUS Technologies, California) was used as the control. One hundred and twenty five cord blood samples were collected (46 from Mt. Hope Women's Hospital (MH) and 79 from the San Fernando General Hospital (SF)). All blood samples were tested in accordance with the two rapid kits and ELISA assay manufacturer's instructions. From 125 cord blood samples, the IgG FOCUS ELISA results showed 93.5 and 95% infections at MH and SF, respectively. Whereas the Brittney and PanBio kits showed 10.9 and 5.1%, and 26.1 and 50.6% for MH and SF, respectively. Based on the FOCUS ELISA (control) assays, the combined seroprevalence rate from north and south Trinidad was 94.4%. IgG and IgM sensitivity and specificity levels were higher in the PanBio than Brittney test kits. The high seroprevalence rates observed in Trinidad are discussed to stimulate more research to explain this phenomenon and to prevent the Southeast Asian scenario from developing in the Americas.

Biomarkers and surrogate end points for fit-for-purpose development and regulatory evaluation of new drugs

A consistent framework for the acceptance and qualification of biomarkers for regulatory use is needed to facilitate innovative and efficient research and subsequent application of biomarkers in drug development. One key activity is biomarker qualification, a graded, "fit-for-purpose" evidentiary process linking a biomarker with biology and clinical end points. A biomarker consortium model will distribute cost and risk, and drive efficient execution of research and ultimately regulatory acceptance of biomarkers for specific indications.

Social images of medicine and dentistry in Japan. An exploratory study using correspondence analysis

OBJECTIVE

To investigate social images associated with dentistry in comparison with nine other medical disciplines.

DESIGN

A questionnaire survey among members of the general public. Subjects were asked to state, in not more than five words, the images which they associated with each of the ten disciplines.

SETTING

Komaki City, Shikatsu Town and Nagoya City in Japan.

PARTICIPANTS

261 respondents from a convenience sample of 300 residents, not associated with any branch of medicine.

OUTCOME MEASURES

Frequency distribution of word images used on at least five occasions and a correspondence analysis of the responses for the ten disciplines.

RESULTS

Of the 163 coded image items, 60 were related to internal medicine, 56 to dentistry, 55 to dermatology, 51 to orthopaedic surgery, 51 to ophthalmology, 50 to surgery, 47 to obstetrics and gynaecology, 43 to otolaryngology, 40 to paediatrics and 33 to psychiatry. Correspondence analysis applied to the 163 items and 10 medical disciplines indicated that three similar paired image groups were found, namely between dermatology and ophthalmology, surgery and orthopaedic surgery, and between dentistry and internal medicine, which were the more commonly encountered disciplines across all age groups. However, compared with the other specialities, dentistry had a significantly greater association with pain, this response being four times more common than for surgery.

CONCLUSIONS

This group of members of the public in Japan perceived dentistry-associated images in a similar way to internal medicine, but the negative associations with pain need to be addressed by the dental profession and health educators alike.

Human Sperm Do Not Bind to Rat Zonae Pellucidae Despite the Presence of Four Homologous Glycoproteins

The specificity of sperm-egg recognition in mammals is mediated primarily by the zona pellucida surrounding ovulated eggs. Mouse sperm are quite promiscuous and bind to human eggs, but human spermatozoa will not bind to mouse eggs. The mouse zona pellucida contains three glycoproteins, ZP1, ZP2, and ZP3, which are conserved in rat and human. The recent observation that human zonae pellucidae contain a fourth protein raises the possibility that the presence of four zona proteins will support human sperm binding. Using mass spectrometry, four proteins that are similar in size and share 62-70% amino acid identity with human ZP1, ZP2, ZP3, and ZP4/ZPB were detected in rat zonae pellucidae. However, although mouse and rat spermatozoa bind to eggs from each rodent, human sperm bind to neither, and the presence of human follicular fluid did not alter the specificity of sperm binding. In addition, mutant mouse eggs lacking hybrid/complex N-glycans or deficient in Core 2 O-glycans were no more able to support human sperm binding than normal mouse eggs. These data suggest that the presence of four zona proteins are not sufficient to support human sperm binding to rodent eggs and that additional determinants must be responsible for taxon-specific fertilization among mammals.

Inactivation of the Mgat1 gene in oocytes impairs oogenesis, but embryos lacking complex and hybrid N-glycans develop and implant

Complex and hybrid N-glycans contain sugar residues that have been implicated in fertilization, compaction of the embryo, and implantation. Inactivation of the Mgat1 gene responsible for their synthesis is embryonic lethal, but homozygous mutant blastocysts are phenotypically normal due to the presence of maternal Mgat1 gene transcripts. To identify roles for complex and hybrid N-glycans in oogenesis and preimplantation development, the Mgat1 gene in oocytes was deleted by using a ZP3Cre recombinase transgene. All mutant oocytes had an altered zona pellucida (ZP) that was thinner than the control ZP, and they did not possess complex N-glycans but contained ZP1, ZP2, and ZP3 glycoproteins. Mutant eggs were fertilized, all embryos implanted, and heterozygotes developed to birth. However, mutant females had decreased fertility, yielded fewer eggs after stimulation with gonadotropins, and produced a reduced number of preimplantation embryos and less progeny than controls. About 25% of embryonic day 3.5 (E3.5) embryos derived from mutant eggs were severely retarded in development, even when they were heterozygous and expressed complex N-glycans. Thus, a proportion of Mgat1(-)(/)(-) oocytes were developmentally compromised. Surprisingly, mutant eggs also gave rise to Mgat1(-)(/)(-) embryos that developed normally, implanted, and progressed to E9.5. Therefore, complex or hybrid N-glycans are required at some stage of oogenesis for the generation of a developmentally competent oocyte, but fertilization, blastogenesis, and implantation may proceed in their absence.

DNA sequence and analysis of human chromosome 9

Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.