Acute neuronal injury and blood genomic profiles in a nonhuman primate model for ischemic stroke.

The goal of this study was to characterize acute neuronal injury in a novel nonhuman primate (NHP) ischemic stroke model by using multiple outcome measures. Silk sutures were inserted into the M1 segment of the middle cerebral artery of rhesus macaques to achieve permanent occlusion of the vessel. The sutures were introduced via the femoral artery by using endovascular microcatheterization techniques. Within hours after middle cerebral artery occlusion (MCAO), infarction was detectable by using diffusion-weighted MRI imaging. The infarcts expanded by 24 h after MCAO and then were detectable on T2-weighted images. The infarcts seen by MRI were consistent with neuronal injury demonstrated histologically. Neurobehavioral function after MCAO was determined by using 2 neurologic testing scales. Neurologic assessments indicated that impairment after ischemia was limited to motor function in the contralateral arm; other neurologic and behavioral parameters were largely unaffected. We also used microarrays to examine gene expression profiles in peripheral blood mononuclear cells after MCAO-induced ischemia. Several genes were altered in a time-dependent manner after MCAO, suggesting that this ischemia model may be suitable for identifying blood biomarkers associated with the presence and severity of ischemia. This NHP stroke model likely will facilitate the elucidation of mechanisms associated with acute neuronal injury after ischemia. In addition, the ability to identify candidate blood biomarkers in NHP after ischemia may prompt the development of new strategies for the diagnosis and treatment of ischemic stroke in humans.

Long-distance transportation of primate embryos developing in culture: a preliminary study.

Non-human primate embryos are invaluable for conducting research relevant to human infertility and stem cells, but their availability is restricted. In this preliminary study, rhesus monkey embryos were produced by IVF at the Caribbean Primate Research Centre and shipped in tubes of gassed culture medium within a battery-powered transport incubator by overnight courier to Wayne State University in Michigan. Upon arrival, the embryos were incubated in fresh culture medium to evaluate further development. In 11 shipments comprising 98 cleavage-stage embryos developing from oocytes that were mature (MII) upon collection, 51 (52%) reached advanced preimplantation stages (morula to hatched blastocyst) during prolonged culture following transportation. However, most embryos produced from oocytes that were immature (MI) at collection arrested and only 5/51 (10%) reached advanced stages of development. This study demonstrates that non-cryopreserved primate embryos can be routinely transported between distant sites without loss of developmental ability. In this way, the processes of production and study of non-cryopreserved primate embryos need not be restricted to the same or nearby laboratories. This will expand the use of these embryos for research and facilitate generation of translationally relevant information.

Effects of in vitro maturation and age on oocyte quality in the rhesus macaque Macaca mulatta.

OBJECTIVE: To evaluate oocyte quality in a primate model. DESIGN: Analysis of oocyte karyotype by chromosome spreading and oocyte spindles by confocal microscopy. SETTING: Research laboratory, Caribbean Primate Research Center. ANIMAL(S): Rhesus macaques aged 6-22 years. INTERVENTION(S): Fourteen females underwent both Regimen A (FSH + hCG) and Regimen B (FSH only) stimulation cycles to facilitate collection of mature and immature oocytes. Immature oocytes from Regimens A and B underwent in vitro maturation (IVM) to produce metaphase II oocytes. All metaphase II oocytes underwent gradual fixation to spread chromosomes or were fixed and stained with probes specific to alpha-tubulin, actin, and DNA for visualization of the meiotic spindle using confocal microscopy. MAIN OUTCOME MEASURE(S): Karyotype and meiotic spindle architecture differences among in vivo matured (IVO) and IVM oocytes from young and old rhesus macaques. RESULT(S): In all, 4.7% of IVO oocytes (Regimen A) from young females were hyperhaploid versus 25.0% of IVM oocytes (Regimen B) from old females; 4.5% of IVO oocytes (Regimen A) from young females versus 51.5% of IVM oocytes (Regimen B) from old females displayed abnormal chromosome alignment on the metaphase spindle. CONCLUSION(S): IVM can induce meiotic anomalies in macaque oocytes, especially those obtained from older females. Results from this study provide possible explanations for the reported reduction in developmental competence of IVM primate oocytes.