No abstract

Previously we reported that prepubertally ovariectomized mice that received young transplanted ovaries at a postreproductive age showed a 40% increase in life expectancy. To study this phenomenon in greater detail, 11-month-old ovariectomized and ovary-intact CBA/J mice underwent ovarian transplantation with 60-day-old ovaries or a sham surgery. Results from observations on transplant recipients in the current study extended our previous results. Whereas intact control mice lived an average of 726 days, transplant recipients lived an average of 770 days (i.e., 780 days for intact recipients and 757 days for ovariectomized recipients). If intact recipients had ceased reproductive cycling by the time of transplant, we observed a further increase in mean life span to 811 days. These results demonstrate that young ovaries enhanced longevity when transplanted to old mice and that ovarian status, examined by means of ovariectomy and ovarian transplantation, clearly influenced the potential of young transplanted ovaries to positively impact longevity.

Changes in placental development have been associated with foetal abnormalities after in vitro embryo manipulations. This study was designed to investigate bovine conceptus development and substrate levels in plasma and fluids in in vivo-and in vitro-produced (IVP) concepti and neonates. In vivo-produced and IVP embryos were derived by established embryo production procedures. Pregnant animals from both groups were slaughtered on days 90 or 180 of gestation, or allowed to go to term. Conceptus and neonatal physical traits were recorded; foetal, maternal and neonatal blood, and foetal fluids were collected for the determination of blood and fluid chemistry, and glucose, fructose and lactate concentrations. Placental transcripts for specific glucose transporters were determined by quantitative RT-PCR. No significant differences in uterine and conceptus traits were observed between groups on day 90. On day 180, larger uterine, placental and foetal weights, and an increase in placental gross surface area (SA) in IVP pregnancies were associated with increased glucose and fructose accumulation in foetal plasma and associated fluids, with no differences in the expression of components of the glucose transporter system. Therefore, the enlarged placental SA in IVP pregnancies suggests an increase in substrate uptake and transport capacity. Newborn IVP calves displayed higher birth weights and plasma fructose concentrations soon after birth, findings which appeared to be associated with clinical and metabolic distress. Our results indicated larger concepti and increased placental fructogenic capacity in mid-to late IVP pregnancies, features which appeared to be associated with an enhanced substrate supply, potentially glucose, to the conceptus.

Adeno-associated virus (AAV) vectors are currently being tested not only in small animal models such as mice but also in large animal models, including pigs, dogs, and horses. Natural exposure to AAV occurs in most of the species used in these studies and potentially elicits a neutralizing humoral immune response to AAV. In this study, we show the prevalence of neutralizing antibodies (NAbs) to several AAV serotypes in these large animals as measured by an in vitro NAb assay and the ability of these NAbs to block AAV transduction in an in vivo mouse model of NAb passive transfer assay. The results of this study clearly show the importance of evaluating large animal models for the presence of AAV NAbs before enrolling them in AAV-mediated gene therapy studies.

Although a majority of clones are born normal and apparently healthy, mortality rates of nearly 30% are described in many reports. Such losses are a major limitation of cloning technology and represent substantial economic investment as well as justifiable animal health and welfare concerns. Prospective, controlled studies are needed to understand fully the causes of neonatal mortality in clones and to develop preventive and therapeutic strategies to minimize losses. We report here the findings of studies on the hematologic and biochemical profiles of cloned and control calves in the immediate 48-h postpartum period. Cloned calves were similar to control calves for a majority of parameters studied including blood gases, concentrations of plasma proteins, minerals and electrolytes, and white blood cell, neutrophil, lymphocyte, and platelet counts. The most notable differences between clones and controls in this study were reduced red- and white-blood cell counts in clones at birth and 1 h of age. As a group, plasma electrolyte concentrations were more variable in clones, and the variability tended to be shifted either higher (sodium, chloride) or lower (potassium, bicarbonate) than in controls. Previously, we noted differences in carbohydrate parameters, the length of time required for clones to make the neonatal adaptation to life ex utero, and morphology of the cloned placenta. Taken together, our findings suggest that cloned calves experience greater difficulty adjusting to life ex utero and that further research is warranted to determine the nature of the relationship between the physiological differences noted here in clones at birth and concomitant abnormal placental morphology.

The period immediately after birth is a vital time for all newborn calves as the cardiovascular, respiratory, and other organ systems adapt to life ex utero. Reported neonatal mortality rates suggest this period to be especially critical in cloned calves; yet prospective, controlled studies on the physiological status of these calves are lacking. The objectives of this study were to compare neonatal (birth to 48 h of age) physical and clinical characteristics and placental morphology of cloned and embryo transfer control calves delivered by cesarean section after induced labor. All calves were raised under specialized neonatal-care protocols at a large-animal veterinary research and teaching hospital. Cloned calves were similar to controls for many parameters studied. Notable exceptions included developmental delays of important physical adjustment parameters and enlargement of the umbilical region. Placentas associated with cloned calves contained fewer total placentomes, a twofold increase in surface area and mass per placentome, and a shift in placentome morphology toward larger, flatter placentomes. The most striking clinical variations detected in clones were hypoglycemia and hyperfructosemia, both measures of carbohydrate metabolism. Because the placenta is known to be the source of plasma fructose in newborn calves, increased fructose production by the cloned placenta may be an important factor in the etiology of umbilical and cardiac anomalies in clones observed in this and other studies.

Caloric restriction (CR) increases the preservation of the ovarian primordial follicular reserve, which can potentially delay menopause. Rapamycin also increases preservation on the ovarian reserve, with similar mechanism to CR. Therefore, the aim of our study was to evaluate the effects of rapamycin and CR on metabolism, ovarian reserve, and gene expression in mice. Thirty-six female mice were allocated into three groups: control, rapamycin-treated (4 mg/kg body weight every other day), and 30% CR. Caloric restricted females had lower body weight (P < 0.05) and increased insulin sensitivity (P = 0.003), while rapamycin injection did not change body weight (P > 0.05) and induced insulin resistance (P < 0.05). Both CR and rapamycin females displayed a higher number of primordial follicles (P = 0.02 and 0.04, respectively), fewer primary, secondary, and tertiary follicles (P < 0.05) and displayed increased ovarian Foxo3a gene expression (P < 0.05). Despite the divergent metabolic effects of the CR and rapamycin treatments, females from both groups displayed a similar increase in ovarian reserve, which was associated with higher expression of ovarian Foxo3a.

Potential applications of somatic cell nuclear transfer to agriculture and medicine are currently constrained by low efficiency and high rates of embryonic, fetal, and neonatal loss. Nuclear transfer efficiency in cattle was compared between three donor-cell treatments from a single animal, between four donor-cell treatments in sequential stages of differentiation from a single cell lineage and genotype, and between the same cell type in two donors. Cumulus and granulosa donor cells resulted in a greater proportion of viable day-7 embryos than ear-skin cells; pregnancy rate and losses were not different among treatments. The least differentiated cell type in the follicular cell lineage, preantral follicle cells, resulted in fewer cloned blastocysts (11%) than cumulus (30%), granulosa (23%), and luteal (25%) donor cells. Cloned blastocysts that did develop from preantral follicle cells (75%) were more likely to progress through implantation into later stages of pregnancy than cloned blastocysts from cumulus (10%), granulosa (9%), and luteal (11%) donor cells (p < 0.05). Day-7 embryo development from granulosa cells was similar between two donors (19 vs. 24%) and proved to be a poor indicator of further development as day-30 pregnancy rates varied threefold between donors (48 vs. 15%, p < 0.05). Results reported here emphasize the crucial role of the nuclear donor cell in the outcome of the nuclear-transfer process.