Blastocyst score affects implantation and pregnancy outcome: towards a single blastocyst transfer

OBJECTIVE

To determine the relationship between blastocyst score and pregnancy outcome.

DESIGN

Retrospective review of blastocyst transfer in an IVF clinic.

SETTING

Private assisted reproductive technology unit.

PATIENT(S)

107 patients undergoing blastocyst culture and transfer of two embryos.

INTERVENTION(S)

Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5), followed by transfer of two blastocysts.

MAIN OUTCOME MEASURE(S)

Implantation rates, pregnancy rates, and twinning were analyzed.

RESULT(S)

When a patient received two top-scoring blastocysts (64% of patients), implantation and pregnancy rates were 70% and 87%, respectively. The twinning rate in this group was 61%. When only one top-quality blastocyst was available for transfer (21% of patients), the implantation and pregnancy rates were 50% and 70%. The twinning rate for this group was 50%. In contrast, when only low-scoring blastocysts were available for transfer (15% of patients), implantation and pregnancy rates were 28% and 44%, and the twinning rate was 29%. No monozygotic twins were observed in this group of patients.

CONCLUSION(S)

The ability to transfer one high-scoring blastocyst should lead to pregnancy rates greater than 60%, without the complication of twins.

Distribution of pre-pro-glucagon and glucagon-like peptide-1 receptor messenger RNAs in the rat central nervous system

Glucagon-like peptide-1 (GLP-1) is derived from the peptide precursor pre-pro-glucagon (PPG) by enzymatic cleavage and acts via its receptor, glucagon-like peptide-1 receptor (GLP-1R). By using riboprobes complementary to PPG and GLP-1R, we described the distribution of PPG and GLP-1R messenger RNAs (mRNAs) in the central nervous system of the rat. PPG mRNA-expressing perikarya were restricted to the nucleus of the solitary tact or to the dorsal and ventral medulla and olfactory bulb. GLP-1R mRNA was detected in numerous brain regions, including the mitral cell layer of the olfactory bulb; temporal cortex; caudal hippocampus; lateral septum; amygdala; nucleus accumbens; ventral pallium; nucleus basalis Meynert; bed nucleus of the stria terminalis; preoptic area; paraventricular, supraoptic, arcuate, and dorsomedial nuclei of the hypothalamus; lateral habenula; zona incerta; substantia innominata; posterior thalamic nuclei; ventral tegmental area; dorsal tegmental, posterodorsal tegmental, and interpeduncular nuclei; substantia nigra, central gray; raphe nuclei; parabrachial nuclei; locus ceruleus, nucleus of the solitary tract; area postrema; dorsal nucleus of the vagus; lateral reticular nucleus; and spinal cord. These studies, in addition to describing the sites of GLP-1 and GLP-1R synthesis, suggest that the efferent connections from the nucleus of the solitary tract are more widespread than previously reported. Although the current role of GLP-1 in regulating neuronal physiology is not known, these studies provide detailed information about the sites of GLP-1 synthesis and potential sites of action, an important first step in evaluating the function of GLP-1 in the brain. The widespread distribution of GLP-1R mRNA-containing cells strongly suggests that GLP-1 not only functions as a satiety factor but also acts as a neurotransmitter or neuromodulator in anatomically and functionally distinct areas of the central nervous system.

Hydroxyldaunomycin (Adriamycin) combination chemotherapy in malignant lymphoma

Combination chemotherapy with CHOP (cyclophosphamide, Adriamycin, vincristine, and prednisone) and HOP (Adrimycin, vincristine, and prednisone, was used as treatment for patients with pathologically staged, advanced non-Hodgkin's lymphoma. Among 204 evaluable patients treated on CHOP there were 71% complete remissions with 92% overall responses. Among the 216 evaluable patients on HOP there were 61% complete remissions and 88% responses. Complete remission rates among patients with histiocytic lymphoma were comparable to those of patients with lymphocytic disease. Patients with nodular lymphoma had higher rates of complete remission than their counterparts with diffuse lymphoma. This was noted with both CHOP (78% vs. 67%) and HOP (67% vs. 60%) induction therapy. Rapid responses were common, as more than 14% of complete remissions and 66% of overall responses were achieved with the first course of treatment. Patients in complete remission have been maintained with either cyclophosphamide, vincristine, and prednisone (COP) or arabinosyl cytosine, vincristine, and prednisone (OAP). After 1 year, 86% of patients on COP and 80% on OAP are projected to be free of disease.

Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers

OBJECTIVE

To determine whether the transfer of blastocysts on day 5, developed in sequential culture media, resulted in an increase in implantation rate compared with embryos transferred on day 3.

DESIGN

Comparative study of embryo culture regimes.

SETTING

Private practice assisted reproductive technology center.

PATIENT(S)

Twenty-three patients undergoing routine IVF cycles.

INTERVENTION(S)

Culture of embryos to day 3 in either standard culture conditions or a serum-free chemically defined medium. One hundred one embryos were subsequently cultured from day 3 to day 5 in a second serum-free medium specifically designed to support development of the blastocyst.

MAIN OUTCOME MEASURE(S)

Embryo cell number and quality on day 3. Blastocyst development on day 5. Implantation rate (determined by fetal heart) and ongoing pregnancy rate (PR).

RESULT(S)

Implantation rates for embryos transferred at the blastocyst stage of development were twice that observed for embryos transferred on day 3, around the eight-cell stage. Significantly more embryos were required for transfer on day 3, compared with day 5, to establish similar PRs.

CONCLUSION(S)

Viable human blastocysts can be obtained in sequential culture media in the absence of coculture and serum. Transfer of blastocysts in IVF will facilitate high PRs while limiting the number of embryos transferred and therefore minimizes the risk of multiple gestation.

Enhanced rates of cleavage and development for sheep zygotes cultured to the blastocyst stage in vitro in the absence of serum and somatic cells: amino acids, vitamins, and culturing embryos in groups stimulate development

The aim of this study was to develop a serum-free culture system that could support high levels of cleavage and blastocyst formation from sheep zygotes developed in vitro. To this end, we investigated the effects on sheep zygote development of amino acids, ammonium, vitamins, and culture of embryos in groups in Synthetic Oviduct Fluid (SOF) medium supplemented with BSA (32 mg/ml). The inclusion of amino acids in the culture medium had no effect on the percentage of embryos arrested at the 8-16-cell stage when embryos were cultured singly in the same drop of medium for 6 days (43% in SOF; 41% in SOF+amino acids). However, in medium containing all Eagle's amino acids, replacing the culture medium every 48 h to alleviate ammonium toxicity significantly decreased the number of arrested embryos (6%; p < 0.05) and significantly increased blastocyst cell number (52 cells in SOF; 105 cells in SOF+amino acids; p < 0.01) and the number of embryos developing to the blastocyst stage (29% in SOF; 67% in SOF+amino acids; p < 0.05). When the medium was renewed every 48 h, nonessential amino acids and glutamine also significantly decreased the number of arrested embryos (p < 0.05). Culturing embryos singly or in groups in SOF medium with all Eagle's amino acids that was renewed every 48 h resulted in significant increases in blastocyst hatching and mean cell number (47%, 31%, and 79%; 105, 136, and 173 cells for embryos cultured singly, in groups of 2, and in groups of 4, respectively). After culture in groups of 4, blastocyst cell numbers were equivalent to in vivo-developed controls (160 cells) and significantly greater than those developed in serum (103 cells; p < 0.01). Analysis of blastocyst metabolism, expressed on a per-cell basis, revealed that amino acids did not affect either glucose uptake or lactate production, whereas the addition of amino acids and vitamins resulted in a significant increase in both parameters (p < 0.01). A similar response was observed in serum-derived blastocysts. Ammonium production by sheep blastocysts after culture in the presence of amino acids was significantly greater than that produced by mouse blastocysts, indirect evidence that ruminant embryos utilize amino acids to a greater extent than do rodent embryos.(ABSTRACT TRUNCATED AT 400 WORDS)

Culture and selection of viable blastocysts: a feasible proposition for human IVF?

In human in-vitro fertilization (IVF) embryos are routinely transferred to the uterus on day 2 or day 3 of development. Resultant implantation and pregnancy rates are disappointingly low, with only approximately 10% of embryos transferred leading to a live birth. The ability to culture embryos to the blastocyst stage should help to resolve this problem by synchronizing the embryo with the female reproductive tract, and by identifying those embryos with little developmental potential. Co-culture has offered a possible means of producing blastocysts capable of high implantation rates. However, recent developments in the field of embryo physiology and metabolism have led to the formulation of new sequential serum-free culture media capable of supporting the development of viable blastocysts in several mammalian species, including the human. It is therefore proposed that blastocyst transfer should be considered for routine use in human IVF. The high viability of blastocysts cultured in the appropriate sequential media means that fewer embryos are required for transfer to achieve a pregnancy, culminating in fewer multiple births. Furthermore, the development of suitable non-invasive tests of embryo viability should further increase the overall success of human IVF by the ability to select before transfer those blastocysts most able to establish a pregnancy.

Amino acids and ammonium regulate mouse embryo development in culture

The regulation of 1-cell mouse embryo development in culture by amino acids was investigated. When the 20 amino acids in Eagle's medium were present, blastocyst formation at 72 h (9%; p < 0.01), and blastocyst cell number (66; p < 0.05) and hatching (45%; p < 0.05) after 96 h of culture were significantly increased, compared to control embryos grown in the absence of amino acids (0%, 60, and 23%, respectively). The beneficial effect of Eagle's amino acids was attributed primarily to the non-essential group. In the presence of non-essential amino acids, blastocyst formation (54%; p < 0.001) and cell number after 72 h of culture (33; p < 0.05), and blastocyst cell number (69; p < 0.01) and hatching (68%; p < 0.01) after 96 h of culture were all significantly greater than for embryos cultured with all amino acids (9%, 26, 66, and 45%, respectively). In the absence of glutamine, essential amino acids significantly reduced blastocyst cell number after 96 h (53; p < 0.05). Continual culture in the presence of amino acids reduced the cleavage rate after around 72 h of in vitro culture; this decrease was not observed in the absence of amino acids. Transfer of embryos to fresh medium after 48-72 h of culture resulted in increases in the percentage of blastocysts formed and in blastocyst cell numbers. These data are consistent with the build-up of an inhibitory compound in the medium, possibly ammonium, an end-product of amino acid metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential regulation of mouse embryo development and viability by amino acids

The amino acid requirements of the preimplantation mouse embryo in culture changes as development proceeds from the zygote to the blastocyst stage. Eagle's non-essential amino acids and glutamine significantly increased cleavage rates during the first four cell cycles, while Eagle's essential amino acids without glutamine did not confer any benefit to embryo development before the eight-cell stage. After the eight-cell stage, non-essential amino acids and glutamine no longer stimulated cleavage rates but significantly increased blastocoel development and blastocyst hatching. In contrast, after the eight-cell stage essential amino acids increased cleavage rates as well as stimulating development of the inner cell mass of the resultant blastocysts. Fetal development after transfer of blastocysts was also significantly increased by culture with essential amino acids from the eight-cell stage. Consequently highest rates of development in vitro and viability after transfer were achieved when embryos were cultured with non-essential amino acids and glutamine to the eight-cell stage followed by development to the blastocyst stage in the presence of all 20 amino acids. Analysis of the parameters measured revealed a significant relationship between number of blastocyst cells and inner cell mass development with viability after transfer. Blastocyst formation and hatching could not be used to assess subsequent developmental potential.

Comparison of statins in hypertriglyceridemia

In 1996, the first 2 studies using 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor ("statin") therapy in hypertriglyceridemic subjects were published. In subjects with isolated triglyceride elevations who were treated with atorvastatin 5, 20, and 80 mg/day, large and dose-related reductions were noted. In subjects with combined hyperlipidemia treated with 10 mg simvastatin, triglyceride reduction similar to that reported for the 5 mg atorvastatin dose was seen. In response to these findings, we conducted comparative assessments to determine whether all statins are effective in lowering triglyceride levels and whether their effect on triglycerides is related to factors such as drug, dose, and baseline triglyceride levels. To standardize these assessments, we devised a ratio that related changes in triglyceride levels to the known predictable response of low-density lipoprotein (LDL) cholesterol to statins. This triglyceride/LDL cholesterol ratio was obtained by dividing the percent change from baseline in the triglyceride level by the percent change from baseline in the LDL cholesterol level. The triglyceride/LDL cholesterol ratio was initially applied to several published studies, and found to be approximately 1.0 and 0.5 in hypertriglyceridemic and nonhypertriglyceridemic populations, respectively. We then assessed the effect of various statins on triglycerides using a pooled laboratory database of 2,689 subjects who had participated in 7 separate studies with similar designs. All of the studies had a placebo run-in followed by a randomized, double-blind, active treatment phase of at least 4 weeks with a statin. Entry into these studies required a triglyceride level of <400 mg/dL. In subjects with baseline triglyceride >250 mg/dL, significant and dose-dependent reductions in triglyceride of 22-45% were seen with all statins. When baseline triglyceride was <150 mg/dL, no significant or dose-dependent effect on triglyceride was seen. The triglyceride/LDL cholesterol ratio was evaluated using a linear model that included baseline triglyceride level, drug, and dose. Only the baseline triglyceride level was significantly (p <0.001) related to this ratio. Moreover, the triglyceride/LDL cholesterol ratio was fairly constant across all statins and doses for patients with baseline triglyceride levels of <150 mg/dL, 150-250 mg/dL, and >250 mg/dL, at 0.0+/-0.3, 0.5+/-0.2, and 1.2+/-0.3, respectively. We conclude that all statins are effective in decreasing triglyceride levels, but only in hypertriglyceridemic patients. Due to the relatively constant triglyceride/LDL cholesterol ratio, our analysis indicates that the more effective the statin is in decreasing LDL cholesterol, the more effective it will also be in decreasing triglyceride levels in patients with hypertriglyceridemia.

Environment of the preimplantation human embryo in vivo: metabolite analysis of oviduct and uterine fluids and metabolism of cumulus cells

OBJECTIVE

To determine the levels of metabolites surrounding the human oocyte and embryo in vivo.

DESIGN

Oviduct and uterine fluids were collected throughout the menstrual cycle. Cumulus cells were collected at oocyte retrieval and their production of metabolites was assessed. Samples were analyzed for pyruvate, lactate, and glucose by microfluorimetry.

PATIENTS

Luminal fluids were collected from naturally cycling patients at the time of routine clinical investigation. Patient consent and hospital ethics approval were obtained for this study.

RESULTS

Pyruvate in the oviduct did not vary with the day of cycle, the mean value was 0.24 mM. Lactate and glucose concentrations varied with the day of cycle; lactate increasing from 4.87 mM in the follicular phase to 10.50 mM at the time of ovulation, whereas glucose decreased from 3.11 mM in the follicular phase to 0.50 mM midcycle and subsequently increased to 2.32 mM in the luteal phase. The concentrations of pyruvate, lactate, and glucose in uterine fluid remained constant throughout the cycle (0.10, 5.87, and 3.15 mM, respectively). All metabolite concentrations in uterine fluid were significantly different from those in the oviduct midcycle. Cumulus cells readily consumed glucose in vitro, with lactate being the major metabolite produced.

CONCLUSION

These data indicate that lactate and glucose concentrations in the oviduct change with day of cycle and that the human embryo is exposed to different metabolite concentrations as it passes along the tract. Furthermore, cumulus cells readily consume glucose, producing lactate. Therefore, the early human embryo is exposed to low glucose and high lactate levels in vivo.

Vitrification of mouse and human blastocysts using a novel cryoloop container-less technique

OBJECTIVE

To vitrify mouse and human blastocysts with use of the cryoloop procedure and to assess subsequent development.

DESIGN

Controlled study of vitrification of mouse and human blastocysts.

SETTING

Research department of a private assisted reproductive technology unit.

PATIENT(S)

Blastocysts that were not suitable to be frozen were donated from patients.

INTERVENTION(S)

Culture of pronucleate embryos in sequential media to the blastocyst stage.

MAIN OUTCOME MEASURE(S)

Survival of the vitrification procedure was assessed by reexpansion, hatching, and outgrowth in culture. In addition, the viability of mouse blastocysts was assessed after transfer to pseudopregnant recipients.

RESULT(S)

Vitrification of mouse blastocysts did not affect the ability to reexpand, hatch, or outgrow in culture. Furthermore, implantation rates and fetal development were equivalent for nonfrozen and vitrified blastocysts. Vitrified human blastocysts were able to hatch and outgrow in culture at rates similar to nonfrozen controls.

CONCLUSION(S)

Cryoloop vitrification was able to cryopreserve mouse and human blastocysts without any reduction in the ability to reexpand and hatch in culture. Furthermore, viability was not reduced by the cryoloop vitrification of mouse blastocysts.

The growth profile, thermotolerance and biofilm formation of Enterobacter sakazakii grown in infant formula milk

AIMS

To study the growth, thermotolerance and biofilm formation of the emergent pathogen Enterobacter sakazakii in infant formula milk (IFM).

METHODS AND RESULTS

The temperature range, death kinetics and biofilm formation of E. sakazakii were determined using impedance microbiology and conventional methods. In IFM the organism grew as low as 6 degrees C and optimally at 37-43 degrees C. In faecal coliform tests, 23% of strains (n = 70) produced gas from lauryl sulphate broth (LSB) at 44 degrees C after 48 h incubation. Three strains failed to grow in LSB at any of the temperatures. The D-value of cells suspended in IFM was determined between 54 and 62 degrees C. The resultant z-value was 5.7 degrees C. The organism was able to adhere and grow on latex, polycarbonate, silicon and to a lesser extent stainless steel.

CONCLUSIONS

Enterobacter sakazakii was able to grow at refrigeration temperatures and on infant-feeding equipment. The thermotolerance of the organism was similar to other Enterobacteriaceae and should be killed during standard pasteurization treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enterobacter sakazakii has been associated with infant meningitis through consumption of contaminated IFM. Enterobacter sakazakii is able to grow in IFM during storage at refrigeration temperatures and attach to infant-feeding equipment, which may become reservoirs of infection.

Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs

OBJECTIVE

To determine whether previously described advanced blastocyst development and high implantation rates are confirmed in an expanded multicenter trial.

DESIGN

Retrospective review.

SETTING

Two private assisted reproductive technology units.

PATIENT(S)

One hundred seventy-four patients who underwent blastocyst culture and transfer.

INTERVENTION(S)

Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5) followed by ET.

MAIN OUTCOME MEASURE(S)

The number and percentage of blastocysts developed, implantation rates, pregnancy rates, and parameters that affected outcome were analyzed.

RESULT(S)

Only 3 of 174 patients failed to achieve blastocyst-stage ET. The mean blastocyst development rate was 48%. The ongoing pregnancy rate was 66.3% per oocyte retrieval, with a mean (+/-SE) of 2.2 +/- 0.05 blastocysts transferred and an implantation rate of 48% per blastocyst transferred.

CONCLUSION(S)

Blastocyst culture and transfer is an effective means of treating patients who respond well to gonadotropins. High pregnancy rates can be accomplished with low numbers of embryos transferred. Patients who failed to achieve ET were rare.

Noninvasive assessment of human embryo nutrient consumption as a measure of developmental potential

OBJECTIVE

To determine the relationship between blastocyst development and morphology and embryo metabolism.

DESIGN

Noninvasive assessment of carbohydrate uptake and ammonium production by individual embryos.

SETTING

Private assisted reproductive technology unit.

PATIENT(S)

Patients donated, with consent, cryopreserved pronucleate embryos and noncryopreserved blastocysts.

INTERVENTION(S)

Culture of 60 thawed pronucleate embryos in sequential media to the blastocyst stage with concomitant noninvasive analysis of embryo metabolism and analysis of 13 blastocysts from noncryopreserved embryos.

MAIN OUTCOME MEASURE(S)

Pyruvate and glucose consumption as well as blastocyst formation and quality.

RESULT(S)

Pyruvate and glucose uptakes on day 4 were significantly higher by embryos that went on to form blastocysts than by embryos that failed to develop to the blastocyst stage. Glucose uptakes were greatest in those blastocysts of highest grade, whereas pyruvate uptakes were similar irrespective of blastocyst grade, indicating that glucose is the more important nutrient for the human blastocyst. Among blastocysts of the same grade from the same patient, there was considerable spread of glucose consumption, indicating that glucose consumption may be of use in identifying blastocysts for transfer. Ammonium production by individual embryos was also measured, reflecting amino acid transamination and use by the human embryo.

CONCLUSION(S)

The ability to identify in culture the embryo with the highest developmental potential will facilitate the move to single-embryo transfers.

Simulated physiological oocyte maturation (SPOM): a novel in vitro maturation system that substantially improves embryo yield and pregnancy outcomes

BACKGROUND

Oocyte in vitro maturation (IVM) reduces the need for gonadotrophin-induced ovarian hyperstimulation and its associated health risks but the unacceptably low conception/pregnancy rates have limited its clinical uptake. We report the development of a novel in vitro simulated physiological oocyte maturation (SPOM) system.

METHODS AND RESULTS

Bovine or mouse cumulus-oocyte complexes (COCs) were treated with cAMP modulators for the first 1-2 h in vitro (pre-IVM), increasing COC cAMP levels ∼100-fold. To maintain oocyte cAMP levels and prevent precocious oocyte maturation, COCs were treated during IVM with an oocyte-specific phosphodiesterase inhibitor and simultaneously induced to mature with FSH. Using SPOM, the pre-IVM and IVM treatments synergized to increase bovine COC gap-junctional communication and slow meiotic progression (both P < 0.05 versus control), extending the normal IVM interval by 6 h in bovine and 4 h in mouse. FSH was required to complete maturation and this required epidermal growth factor signalling. These effects on COC had profound consequences for oocyte developmental potential. In serum-free conditions, SPOM increased bovine blastocyst yield (69 versus 27%) and improved blastocyst quality (184 versus 132 blastomeres; both P < 0.05 versus standard IVM). In mice, SPOM increased (all P < 0.05) blastocyst rate (86 versus 55%; SPOM versus control), implantation rate (53 versus 28%), fetal yield (26 versus 8%) and fetal weight (0.9 versus 0.5 g) to levels matching those of in vivo matured oocytes (conventional IVF).

CONCLUSIONS

SPOM is a new approach to IVM, mimicing some characteristics of oocyte maturation in vivo and substantially improving oocyte developmental outcomes. Adaption of SPOM for clinical application should have significant implications for infertility management and bring important benefits to patients.

Effect of incubation volume and embryo density on the development and viability of mouse embryos in vitro

The morphology, cleavage rate and viability of preimplantation embryos from random bred Swiss mice were assessed after culture in different incubation volumes and embryo densities. Decreasing the incubation volume, from 320 to 20 microliters, significantly increased blastocyst cell number (P less than 0.01) and embryo development after transfer (P less than 0.01). Increasing the number of embryos incubated per drop from 1 to 16 significantly increased the number of two-cell embryos reaching the blastocyst stage in 5 or 320 microliters. Culturing embryos in groups significantly increased blastocyst cell numbers in all volumes employed and elevated embryo viability. Such observations are consistent with the hypothesis that the preimplantation mammalian embryo produces a factor(s) which can stimulate its own development. The results of this study have implications for clinical in-vitro fertilization, where embryos are routinely cultured individually in relatively large volumes.

A cross-link breaker has sustained effects on arterial and ventricular properties in older rhesus monkeys

Nonenzymatic glycosylation and cross-linking of proteins by glucose contributes to an age-associated increase in vascular and myocardial stiffness. Some recently sythesized thiazolium compounds selectively break these protein cross-links, reducing collagen stiffness. We investigated the effects of 3-phenacyl-4,5-dimethylthiazolium chloride (ALT-711) on arterial and left ventricular (LV) properties and their coupling in old, healthy, nondiabetic Macaca mulatta primates (age 21 +/- 3.6 years). Serial measurements of arterial stiffness indices [i.e., aortic pulse wave velocity (PWV) and augmentation (AGI) of carotid arterial pressure waveform] as well as echocardiographic determinations of LV structure and function were made before and for 39 weeks after 11 intramuscular injections of ALT-711 at 1.0 mg/kg body weight every other day. Heart rate, brachial blood pressure, and body weight were unchanged by the drug. PWV and AGI decreased to a nadir at 6 weeks [PWV to 74.2 +/- 4.4% of baseline (B), P = 0.007; AGI to 41 +/- 7.3% of B, P = 0.046], and thereafter gradually returned to baseline. Concomitant increases in LV end diastolic diameter to 116.7 +/- 2.7% of B, P = 0.02; stroke volume index (SV(index)) to 173.1 +/- 40.1% of B, P = 0.01; and systolic fractional shortening to 180 +/- 29.7% of B, P = 0.01 occurred after drug treatment. The LV end systolic pressure/SV(index), an estimate of total LV vascular load, decreased to 60 +/- 12.1% of B (P = 0.02). The LV end systolic diameter/SV(index), an estimate of arterio-ventricular coupling, was improved (decreased to 54.3 +/- 11% of B, P < 0.002). Thus, in healthy older primates without diabetes, ALT-711 improved both arterial and ventricular function and optimized ventriculo-vascular coupling. This previously unidentified cross-link breaker may be an effective pharmacological therapy to improve impaired cardiovascular function that occurs in the context of heart failure associated with aging, diabetes, or hypertension, conditions in which arterial and ventricular stiffness are increased.

The effect of paternal diet-induced obesity on sperm function and fertilization in a mouse model

Although obvious effects of obesity on female reproduction and oocytes are emerging, the effects on male fertility and sperm quality are less clear with studies reporting conflicting results. We hypothesize that male obesity affects sperm function and physiology probably as a result of elevated oxidative stress in spermatozoa and therefore elevated levels of sperm DNA damage and loss of function. Six-week-old C57/Bl6 male mice (n = 36) were randomly allocated to two groups: group 1 (n = 18) received a control diet, whereas group 2 (n = 18) received a high-fat diet (HFD). At the completion of a 9-week period, mice were sacrificed and spermatozoa were obtained. Sperm motility, concentration, intracellular reactive oxygen species (ROS) production and sperm DNA damage were measured. The ability of the sperm to undergo capacitation, acrosome reaction, sperm binding and ability to fertilize an oocyte were also assessed. The percentage of motile spermatozoa was decreased in the HFD group compared with controls (36 ± 2% vs. 44 ± 4%; p < 0.05). Intracellular ROS was elevated (692 ± 83 vs. 409 ± 22 units; p < 0.01) in the HFD group compared with controls. Sperm DNA damage was also increased (1.64 ± 0.6% vs. 0.17 ± 0.06%; p < 0.05) in the HFD group compared with the control group. Furthermore, the percentage of non-capacitated sperm was significantly lower compared with controls (12.34% vs. 21.06%; p < 0.01). The number of sperm bound to each oocyte was significantly lower (41.14 ± 2.5 vs. 58.39 ± 2.4; p < 0.01) in the HFD group compared with that in controls and resulted in significantly lower fertilization rates (25.9% vs. 43.9%; p < 0.01). This report provides evidence that obesity may induce oxidative stress and sperm DNA damage as well as decreased fertilizing ability. This is important as DNA damage in the sperm as a result of oxidative stress has been linked to poor reproductive outcomes.

Recent clinical experience with dronabinol

Dronabinol, delta-9-tetrahydrocannabinol in sesame oil, has been used for several years as an antiemetic for patients receiving cancer chemotherapy. In combination studies with prochlorperazine, enhancement of efficacy, as measured by duration of episodes of nausea and vomiting and by severity of nausea, has been found. The incidence of psychotropic effects from dronabinol appears to be decreased by concomitant administration of prochlorperazine. In open pilot studies, dronabinol caused weight gain in seven of ten patients with symptomatic HIV infection. In both HIV and cancer patients, dronabinol improved appetite at a dose which was well tolerated for chronic administration.

Increase in postimplantation development of cultured mouse embryos by amino acids and induction of fetal retardation and exencephaly by ammonium ions

The effects of amino acids and ammonium on the postimplantation development of cultured preimplantation mouse zygotes were assessed. Development after transfer revealed that the mouse embryo undergoes a switch in nitrogen requirements during the preimplantation period. Although Eagle's nonessential amino acids and glutamine supported the highest implantation and fetal development rates per embryo transferred when zygotes were cultured for 48 h, by 93 h of culture the highest implantation rate was observed when all 20 amino acids were in the culture medium. Furthermore, fetal development per implantation at 69 and 93 h of culture was increased only in the presence of essential amino acids without glutamine. The beneficial effects of amino acids on postimplantation development when embryos were cultured for 4 days required that the medium be renewed after 48 h (at the 6-8-cell stage) to alleviate the build-up of ammonium. Ammonium was shown to induce fetal retardation and exencephaly in a time- and concentration-dependent manner. Renewal of amino-acid-free culture medium reduced fetal mass, providing indirect evidence for the production of an embryo-derived growth factor capable of stimulating postimplantation development. These data demonstrate that inclusion of amino acids in the culture medium for preimplantation embryos significantly increases postimplantation development the preimplantation mouse embryo changes its nitrogen requirement as development proceeds, nonessential amino acids increase the implantation rate while the essential amino acids enhance fetal development, and ammonium in the medium retards fetal development and induces the neural tube defect exencephaly.

Alleviation of the '2-cell block' and development to the blastocyst of CF1 mouse embryos: role of amino acids, EDTA and physical parameters

The role of amino acids, ethylenediaminetetraacetic acid (EDTA), transferrin, oxygen, glucose, glutamine, taurine and ammonium in CF1 mouse zygote development in culture was examined. Non-essential amino acids and glutamine were shown to alleviate the 2-cell block in culture, and acted in synergy with EDTA to facilitate development to the blastocyst stage. In the presence of amino acids and EDTA, transferrin conferred no beneficial effect. Development of zygotes was significantly impaired if amino acids were removed from the collection medium, even when they were subsequently cultured in the presence of amino acids. Zygote development to the blastocyst stage was significantly improved when modular incubator chambers were used compared to using a conventional incubator, and when an oxygen concentration of 7% was used as opposed to 20%. Addition of taurine to medium containing non-essential amino acids had no effect on embryo development, whereas the removal of glutamine and/or glucose from the culture medium significantly reduced blastocyst cell number. Removal of glucose from the culture medium also resulted in a significant decrease in implantations. Ammonium, generated from the breakdown of amino acids, significantly reduced blastocyst development. EDTA was found to confer its beneficial effects during the first 48 h of culture, and indeed was inhibitory during the second 48 h, resulting in loss of subsequent viability. In summary, the data demonstrate that development of CF1 zygotes to the blastocyst stage is readily achievable. In the presence of non-essential amino acids and glutamine the removal of glucose is detrimental to CF1 mouse embryo development in culture and reduces subsequent viability. Optimal development and maintenance of viability requires more than one culture medium to support the preimplantation period.

Selection of viable mouse blastocysts prior to transfer using a metabolic criterion

The success rate of human in-vitro fertilization (IVF) remains low, with only approximately 10% of embryos transferred resulting in a term pregnancy. A major contributor to this embryonic loss is poor embryo development in vitro. Such poor development can be attributed to both chromosomal and anatomic anomalies in oocytes after ovarian stimulation and to suboptimal embryo culture conditions. The low success rate of IVF is compounded by an inability to select those embryos most likely to implant after transfer (viable). Currently morphology is used almost exclusively as the sole criterion to decide which embryos are replaced. This procedure is not only subjective but has a poor correlation with subsequent developmental competence. Therefore, the development of techniques to quantify embryo viability prior to transfer will significantly increase pregnancy rates. We report here that the non-invasive assessment of glycolytic activity (percentage of glucose converted to lactate) in individual mouse blastocysts prior to transfer can be used successfully to identify viable embryos. Blastocysts with a low glycolytic activity, close to that of in-vivo developed blastocysts, had a significantly higher viability than those with abnormally elevated levels of glycolysis. Using glycolytic activity as a marker of viability resulted in a four fold increase in the pregnancy rate compared with embryos selected at random for transfer. We propose that the success of clinical IVF can be increased significantly by employing quantitative tests for viability.

Diet-induced paternal obesity in the absence of diabetes diminishes the reproductive health of two subsequent generations of mice

BACKGROUND

Obesity and related conditions, notably subfertility, are increasingly prevalent. Paternal influences are known to influence offspring health outcome, but the impact of paternal obesity and subfertility on the reproductive health of subsequent generations has been overlooked.

METHODS

A high-fat diet (HFD) was used to induce obesity but not diabetes in male C57Bl6 mice, which were subsequently mated to normal-weight females. First-generation offspring were raised on a control diet and their gametes were investigated for signs of subfertility. Second-generation offspring were generated from both first generation sexes and their gametes were similarly assessed.

RESULTS

We demonstrate a HFD-induced paternal initiation of subfertility in both male and female offspring of two generations of mice. Furthermore, we have shown that diminished reproductive and gamete functions are transmitted through the first generation paternal line to both sexes of the second generation and via the first generation maternal line to second-generation males. Our previous findings that founder male obesity alters the epigenome of sperm, could provide a basis for the developmental programming of subfertility in subsequent generations.

CONCLUSIONS

This is the first observation of paternal transmission of diminished reproductive health to future generations and could have significant implications for the transgenerational amplification of subfertility observed worldwide in humans.

Amino acids and vitamins prevent culture-induced metabolic perturbations and associated loss of viability of mouse blastocysts

Culture of in-vivo-developed mouse blastocysts in a simple culture medium based on a balanced salt solution supplemented with carbohydrates for 3 h significantly perturbed embryo metabolism. Maximal perturbation occurred after just 6 h of culture. Similarly, culture of rat blastocysts in a simple culture medium for 3 h also resulted in perturbed metabolism. Cultured mouse and rat blastocysts both had an abnormally elevated rate of glycolysis of approximately 100% after culture (P < 0.05). Rates of pyruvate oxidation by mouse blastocysts were also significantly reduced after culture in a simple medium for 6 h (P < 0.01). Furthermore, the developmental competence of mouse blastocysts after transfer was significantly reduced by just 6 h of culture in a simple medium (P < 0.05). Addition of Eagle's amino acids or vitamins to the culture medium reduced the perturbation of both the glycolytic activity and oxidative capacity of cultured mouse blastocysts and acted in synergy to further the inhibition. Importantly, culture with amino acids and vitamins prevented any loss of viability of mouse blastocysts after culture for 6 h. It can be concluded that the mouse blastocyst is sensitive to its environment and that culture-induced stress results in the loss of normal cellular function, as manifested in this case by an abnormal pattern of glucose utilization and loss of viability.