Minimally Invasive Subcutaneous Adipose Tissue Biopsy in a Nonhuman Primate Model: Approach and Outcomes

Epigenetic modifiers are being investigated for a number of CNS malignancies as tumor-associated mutations such as isocitrate dehydrogenase mutations (IDH1/IDH2) and H3K27M mutations, which result in aberrant signaling, are identified. We evaluated the CNS exposure of the DNA methyltransferase inhibitor, 5-azacytidine (5-AZA), in preclinical nonhuman primate (NHP) models to inform its clinical development for CNS tumors. 5-AZA and 5-AZA+Inulin pharmacokinetics (PK) were evaluated in NHPs (n = 10) following systemic (intravenous [IV]) and intrathecal (intraventricular [IT-V], intralumbar [IT-L], and cisternal [IT-C]) administration. Plasma, cerebrospinal fluid (CSF), cortical extracellular fluid (ECF), and tissues were collected. 5-AZA levels were quantified via ultra-high-performance liquid chromatography with tandem mass spectrometric detection assay and inulin via ELISA. PK parameters were calculated using noncompartmental methods. After IV administration, minimal plasma exposure (area under the curve [AUC] range: 2.4-3.2 h*µM) and negligible CSF exposure were noted. CSF exposure was notably higher after IT-V administration (AUCINF 1234.6-5368.4 h*µM) compared to IT-L administration (AUCINF 7.5-19.3 h*µM). CSF clearance after IT administration exceeded the mean inulin CSF flow rate of 0.018 ± 0.003 ml/min as determined by inulin IT-V administration. 5-AZA IT-V administration with inulin increased the 5-AZA CSF duration of exposure by 2.2-fold. IT-C administration yielded no quantifiable 5-AZA ECF concentrations but resulted in quantifiable tissue levels. IT administration of 5-AZA is necessary to achieve adequate CNS exposure. IT administration results in pronounced and prolonged 5-AZA CSF exposure above the reported IC50 range for IDH-mutated glioma cell lines. Inulin administered with 5-AZA increased the duration of exposure for 5-AZA.

To provide a comprehensive and current review on the available experimental animal models of retinal vein occlusion (RVO) and to identify their strengths and limitations with the purpose of helping researchers to plan preclinical studies on RVO. A systematic review of the literature on experimental animal models of RVO was undertaken. Medline, SCOPUS, and Web of Science databases were searched. Studies published between January 1, 1965, and March 31, 2017, and that met the inclusion criteria were reviewed. The data extracted included animal species used, methods of inducing RVO, and the clinical and histopathologic features of the models, especially in relation to strengths, limitations, and faithfulness to clinical sequelae. A total of 128 articles fulfilling the inclusion criteria were included. Several species were used to model human branch and central RVO (BRVO; CRVO) with nonhuman primates being the most common, followed by rodents and pigs. BRVO and CRVO were most commonly induced by laser photocoagulation and all models showed early features of clinical disease, including retinal hemorrhages and retinal edema. These features made many of the models adequate for studying the acute phase of BRVO and CRVO, although macular edema, retinal ischemia, and neovascular complications were observed in only a few experimental animal models (laser-induced model in rodents, pigs, and nonhuman primates, diathermy-induced model in pigs, and following intravitreal injection of PD0325901 in rabbits for BRVO; and in the laser-induced model in rodents, rabbits, and nonhuman primates, diathermy-induced model in nonhuman primates, following permanent ligation of the central retinal vein in nonhuman primates, and with intravitreal injection of thrombin in rabbits for CRVO). Experimental animal models of RVO are available to study the pathogenesis of this disease and to evaluate diagnostic/prognostic biomarkers and to develop new therapeutics. Data available suggest laser-induced RVO in pigs and rodents to be overall the best models of BRVO and the laser-induced RVO rodents the best model for CRVO.

BackgroundImprovement in gene modifications of donor pigs has led to the prevention of early cardiac xenograft rejection and significantly prolonged cardiac xenograft survival in both heterotopic and orthotopic preclinical non-human primate (NHP) models. This progress formed the basis for FDA approval for compassionate use transplants in two patients.MethodsBased on our earlier report of 9-month survival of seven gene-edited (7-GE) hearts transplanted (life-supporting orthotopic) in baboons, we transplanted 10 gene-edited pig hearts into baboons (n = 4) using non-ischemic continuous perfusion preservation (NICP) and immunosuppression regimen based on co-stimulation blockade by anti-CD40 monoclonal antibody. This pivotal study expands on the 7-GE backbone, with 3 additional gene edits, using 10-GE pigs as donors to baboon recipients.Results10 GE cardiac xenografts provide life-supporting function up to 225 days (mean 128 ± 36 days) in a non-human primate model. Undetectable or latent porcine cytomegalovirus (PCMV) does not influence cardiac xenograft survival in this study but still needs more exploration with a larger cohort. Xenograft histology demonstrates adipose (Fat) deposition (n = 1), chronic vasculopathy (n = 1), micro and macro thrombosis, and acute cellular rejection (n = 1).ConclusionsThese data demonstrate that 10 GE cardiac xenografts have variable cardiac xenograft survival in NHP due to perhaps presence of 4th antigen and require further study. However, these 10GE organs may be suitable for clinical cardiac xenotransplantation and have already been utilized in two human cases.

Objective: To evaluate the biological function of cervical subtotal discectomy prosthesis (CSDP) implantation in a non-human primate model. Methods: A CSDP was tested for cytocompatibility and osseointegration capacity before implantation in non-human primates. Subsequently, the CSDP was improved based on three-dimensional CT measurements of the non-human primate cervical spine. Eight cynomolgus monkeys were selected for removal of the intervertebral disc and lower endplate of the C5/6 segment to complete the model construction for CSDP implantation. In 18-month follow-up, physiological indices, radiology, and kinematics were assessed to estimate the biological function of the CSDP in non-human primates, including biosafety, osseointegration, and biomechanics. Results: Co-cultured with the CSDP constituent titanium alloy (Ti6Al4V-AO), the mouse embryo osteoblast precursor cell MC3T3-E1 obtained extended adhesion, remarkable viability status, and cell proliferation. After implantation in the mouse femur for 28 days, the surface of Ti6Al4V-AO was covered by a large amount of new cancellous bone, which formed further connections with the femur cortical bone, and no toxicity was detected by blood physiology indices or histopathology. After completing implantation in primate models, no infection or osteolysis was observed, nor was any subsidence or displacement of the CSDP observed in CT scans in the 18-month follow-up. In particular, the interior of the cervical vertebra fixation structure was gradually filled with new trabecular bone, and the CSDP had achieved fixation and bony fusion in the vertebral body at 1 year post-operation. Meanwhile, no signs of inflammation, spinal cord compression, adjacent segment degeneration, or force line changes were observed in subsequent MRI observations. Moreover, there were no pathological changes of the joint trajectory, joint motion range, stride length, or the stance phase ratio revealed in the kinematics analysis at 3, 6, 12, or 18 months after CSDP implantation. Conclusion: We successfully designed a new cervical subtotal discectomy prosthesis and constructed an excellent non-human primate implantation model for the evaluation of subtotal disc replacement arthroplasty. Furthermore, we demonstrated that CSDP had outstanding safety, osseointegration capacity, and biomechanical stability in a non-human primate model, which might be a new choice in the treatment of cervical disc diseases and potentially change future outcomes of degenerative cervical diseases.

Diffuse intrinsic pontine glioma (DIPG) is one of the deadliest forms of childhood cancers. To date, no effective treatment options have been developed. Recent drug screening studies identified the HDAC inhibitor panobinostat as an active agent against DIPG cells lines and animal models. To guide in the clinical development of panobinostat, we evaluated the CNS pharmacokinetics of panobinostat using CSF as a surrogate to CNS tissue penetration in a pre-clinical nonhuman primate (NHP) model after oral administration. Panobinostat was administered orally to NHP (n = 3) at doses 1.0, 1.8, 2.4, and 3.0mg/kg (human equivalent dose: 20, 36, 48, 60mg/m2, respectively). The subjects served as their own controls where possible. Serial, paired CSF and plasma samples were collected for 0-48h. Panobinostat was quantified via a validated uHPLC-MS/MS method. Pharmacokinetic (PK) parameters were calculated using non-compartmental methods. CSF penetration of panobinostat after systemic delivery was low, with levels detectable in only two subjects. The CSF penetration of panobinostat was low following oral administration in this pre-clinical NHP model predictive of human PK.

Influenza virus infection is a seasonal infectious disease for humans, whereas it is also a zoonosis that is originally transmitted from animals to humans. Therefore, several animal models are used in research on influenza virus infection. We have used a nonhuman primate (NHP) model to extrapolate pathogenicity of various influenza viruses and efficacy of vaccines and antiviral drugs against the influenza viruses in humans. NHPs have genes, anatomical structure, and immune responses similar to those of humans as compared to other animal models. Using an NHP model, we revealed that the pandemic 2009 influenza A virus caused viral pneumonia as reported in human patients. Thus, it is thought that NHP models can be used to predict replication of emerging viruses in humans. We also examined the pathogenicity of highly pathogenic avian influenza viruses and evaluated a new therapeutic antibody in macaques under an immunocompromised condition. NHP models have provided promising results in research on other infectious diseases including Ebola virus and human/simian immunodeficiency virus infections. Thus, NHPs are important in biomedical research for determining the pathogenesis and for development of treatments, especially when clinical trials are difficult. We summarize the characteristics and advantages of research using NHP models in this review.

Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the important complications of neonatal asphyxia, which not only leads to neurological disability but also seriously threatens the life of neonates. Over the years, animal models of HIE have been a research hotspot to find ways to cope with HIE and thereby reduce the risk of neonatal death or disability in moderate-to-severe HIE. By reviewing the literature related to HIE over the years, it was found that nonhuman primates share a high degree of homology with human gross neural anatomy. The basic data on nonhuman primates are not yet complete, so it is urgent to mine and develop new nonhuman primate model data. In recent years, the research on nonhuman primate HIE models has been gradually enriched and the content is more novel. Therefore, the purpose of this review is to further summarize the methods for establishing the nonhuman primate HIE model and to better elucidate the relevance of the nonhuman primate model to humans by observing the behavioral manifestations, neuropathology, and a series of biomarkers of HIE in primates HIE. Finally, the most popular and desirable treatments studied in nonhuman primate models in the past 5 years are summarized.

Porcine islet xenotransplantation is a promising alternative to overcome the shortage of organ donors. For the successful application of islet xenotransplantation, robust immune/inflammatory responses against porcine islets should be thoroughly controlled. Over the last few decades, there have been numerous attempts to surmount xenogeneic immune barriers. In this review, we summarize the current progress in immunomodulatory therapy for the clinical application of porcine islet xenotransplantation. Long-term graft survival of porcine islets was achieved by using anti-CD154 Ab-based regimens in a preclinical non-human primate (NHP) model. However, owing to a serious complication of thromboembolism in clinical trials, the development of an anti-CD154 Ab-sparing immunosuppressant procedure is required. The efficacy of new immunosuppressive practices that employ anti-CD40 Abs or other immunosuppressive reagents has been tested in a NHP model to realize their utility in porcine islet xenotransplantation. The recent progress in the development of immunomodulatory approaches, including the immunosuppressive regimen, which enables long-term graft survival in a pig-to-non-human primate islet xenotransplantation model, with their potential clinical applicability was reviewed.

Mouse and Non-human Primate Models for EV71 Disease

In vivo imaging in NHP models of malaria: Challenges, progress and outlooks

Natural killer (NK) cells are the major innate effectors primed to eliminate virus-infected and tumor or neoplastic cells. Recent studies also suggest nuances in phenotypic and functional characteristics among NK cell subsets may further permit execution of regulatory and adaptive roles. Animal models, particularly non-human primate (NHP) models, are critical for characterizing NK cell biology in disease and under homeostatic conditions. In HIV infection, NK cells mediate multiple antiviral functions via upregulation of activating receptors, inflammatory cytokine secretion, and antibody dependent cell cytotoxicity through antibody Fc-FcR interaction and others. However, HIV infection can also reciprocally modulate NK cells directly or indirectly, leading to impaired/ineffective NK cell responses. In this review, we will describe multiple aspects of NK cell biology in HIV/SIV infections and their association with viral control and disease progression, and how NHP models were critical in detailing each finding. Further, we will discuss the effect of NK cell depletion in SIV-infected NHP and the characteristics of newly described memory NK cells in NHP models and different mouse strains. Overall, we propose that the role of NK cells in controlling viral infections remains incompletely understood and that NHP models are indispensable in order to efficiently address these deficits.

Non-human primate (NHP) models of Parkinson disease show many similarities with the human disease. They are very useful to test novel pharmacotherapies as reviewed here. The various NHP models of this disease are described with their characteristics including the macaque, the marmoset, and the squirrel monkey models. Lesion-induced and genetic models are described. There is no drug to slow, delay, stop, or cure Parkinson disease; available treatments are symptomatic. The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-Dopa) still remains the gold standard symptomatic treatment of Parkinson. However, involuntary movements termed L-Dopa-induced dyskinesias appear in most patients after chronic treatment and may become disabling. Dyskinesias are very difficult to manage and there is only amantadine approved providing only a modest benefit. In this respect, NHP models have been useful to seek new drug targets, since they reproduce motor complications observed in parkinsonian patients. Therapies to treat motor symptoms in NHP models are reviewed with a discussion of their translational value to humans. Disease-modifying treatments tested in NHP are reviewed as well as surgical treatments. Many biochemical changes in the brain of post-mortem Parkinson disease patients with dyskinesias are reviewed and compare well with those observed in NHP models. Non-motor symptoms can be categorized into psychiatric, autonomic, and sensory symptoms. These symptoms are present in most parkinsonian patients and are already installed many years before the pre-motor phase of the disease. The translational usefulness of NHP models of Parkinson is discussed for non-motor symptoms.

Purpose The present study was carried out to evaluate the radioprotective activities of N-acetyl-L-tryptophan (L-NAT) using rodent and non-human primate (NHP) models. Materials and methods The antagonistic effect of L-NAT on the Transient receptor potential vanilloid-1 (TRPV1) receptor and substance P inhibition was determined using molecular docking and Elisa assays. The in vivo radioprotective activity of L-NAT was evaluated using whole-body survival assays in mice and NHPs. Radioprotective activity of L-NAT was also determined at the systemic level using quantitative histological analysis of bone marrow, jejunum, and seminiferous tubules of irradiated mice. Results Molecular docking studies revealed a strong binding of L-NAT with TRPV1 receptor at similar binding pockets to which capsaicin, an agonist of the TRPV1 receptor, binds. Further, capsaicin and gamma radiation were found to induce substance P levels in the intestines and serum of the mice, while L-NAT pretreatment was found to inhibit it. Significant whole-body survival (>80%) was observed in irradiated (9.0 Gy) mice that pretreated with L-NAT (150 mg/kg, b.wt. im) compared to 0% survival in irradiated mice that not pretreated with L-NAT. The quantitative histology of the hematopoietic, gastrointestinal, and male reproductive systems demonstrated significant protection against radiation-induced cellular degeneration. Interestingly, 100% survival was observed with irradiated NHPs (6.5 Gy) that pretreated with L-NAT (37.5 mg/kg, b.wt.im). Significant improvement in the hematology profile was observed after days 10-20 post-treatment periods in irradiated (6.5 Gy) NHPs that were pretreated with L-NAT. Conclusion L-NAT demonstrated excellent radioprotective activity in the mice and NHP models, probably by antagonizing TRPV1 receptor and subsequently inhibiting substance P expression.

A biocompatible gelatin sponge scaffold confers robust tissue remodeling after spinal cord injury in a non-human primate model

Porcine islets are a major focus of current research in nonhuman primate xenotransplantation models. Major advances have been obtained recently and these are briefly described. Reports by three independent centres have described 6-month porcine islet xenograft survival in nonhuman primates. Two of these have obtained such results by interfering with the CD40/CD154 co-stimulatory pathway. While these results are groundbreaking, the immunosuppressive regimens used are not viewed as clinically applicable and will need to be modified before islet xenotransplantation can be considered for clinical trials. In contrast, preliminary results by Gianello and colleagues have demonstrated 6-month survival of diabetic nonhuman primates transplanted subcutaneously with encapsulated porcine islets, in the complete absence of immunosuppression. The confirmation and full assessment of these results are eagerly awaited. Importantly, to date, no evidence of xenozoonoses has been observed following porcine islet xenotransplantation to nonhuman primates. Of the possible organ candidates for xenotransplantation, porcine islets are the closest to a possible clinical application. Prior to the initiation of ethical and safe clinical trials, however, further efforts to generate additional efficacy and safety data in the nonhuman primate model will be indispensable.