Description of a Nonhuman Primate Model of Retinal Ischemia/Reperfusion Injury.

Purpose: To establish an inducible model of retinal ischemia/reperfusion injury (RI/RI) in nonhuman primates (NHPs) to improve our understanding of the disease conditions and evaluate treatment interventions in humans. Methods: We cannulated the right eye of rhesus macaques with a needle attached to a normal saline solution reservoir at up to 1.9 m above the eye level that resulted in high intraocular pressure of over 100 mm Hg for 90 minutes. Retinal morphology and function were monitored before and after RI/RI over two months by fundus photography, optical coherence tomography, electroretinography, and visual evoked potential. Terminal experiments involved immunostaining for retinal ganglion cell marker Brn3a, glial fibrillary acidic protein, and quantitative polymerase chain reaction to assess retinal inflammatory biomarkers. Results: We observed significant and progressive declines in retinal and retinal nerve fiber layer thickness in the affected eye after RI/RI. We noted significant reductions in amplitudes of electroretinography a-wave, b-wave, and visual evoked potential N2-P2, with minimal recovery at 63 days after injury. Terminal experiments conducted two months after injury revealed ∼73% loss of retinal ganglion cells and a fivefold increase in glial fibrillary acid protein immunofluorescence intensity compared to the uninjured eyes. We observed marked increases in tumor necrosis factor-alpha, interferon-gamma, interleukin-1beta, and inducible nitric oxide synthase in the injured retinas. Conclusions: The results demonstrated that the pathophysiology observed in the NHP model of RI/RI is comparable to that of human diseases and suggest that the NHP model may serve as a valuable tool for translating interventions into viable treatment approaches. Translational Relevance: The model serves as a useful platform to study potential interventions and treatments for RI/RI or blinding retinal diseases.

Homotypic targeting of immunomodulatory nanoparticles for enhanced peripheral and central immunity.

OBJECTIVES: Synthetic oligodeoxynucleotides (ODNs) that contain unmethylated cytosine-phosphate-guanine (CpG) motifs serve as immune adjuvants in disease treatment. However, the poor cell permeability and safety concerns limit their medical applications, and biocompatible strategies for efficient delivery of functional CpG ODNs are highly desirable. MATERIALS AND METHODS: Self-assembled, cell membrane-coated CpG nanoparticles (NP) are prepared, and their physicochemical properties are characterized. The uncoated and membrane-coated CpG NP are compared for their biocompatibility, cellular uptake kinetics, endocytic pathways, subcellular localization, and immunostimulatory activities in macrophages and microglia. RESULTS: Macrophage- or microglia-derived cell membrane camouflaging alters the endocytic pathways of CpG NP, promotes their targeted delivery to the cells with homologous membrane, ensures their endosomal localization, and enhances their immunomodulatory effects. CONCLUSIONS: We design a type of biomimetic NP consisting of self-assembled CpG NP core and cell membrane shell, and demonstrate its advantages in the modulation of peripheral and central immune cells. Our study provides a new strategy for the application of CpG ODNs.

Comparison of the clinical manifestations of type 2 diabetes mellitus between rhesus monkey (Macaca mulatta lasiotis) and human being.

OBJECTIVES: Type 2 diabetes mellitus (T2DM) is the most common form of diabetes. To determine the similarities of development of T2DM between rhesus monkey [Macaca mulatta lasiotis (M. m. lasiotis)] and human being, the clinical parameters were determined during a period of 2 years in 60 adult male rhesus monkeys (M. m. lasiotis). METHODS: Sixty male monkeys whose fasting plasma glucose (FPG) level less than or equal to 5 mmol/L (90 mg/dL) were enrolled in this study. Of these, 50 monkeys aged 7 to 20 years were fed with high-fat diet and 10 aged 4 to 10 years fed with standard diet as normal monkeys. Body weight, body mass index, FPG, fasting plasma insulin, and hemoglobin A1c levels were measured and calculated. The responses of insulin and glucose levels to intravenous glucose tolerance test were analyzed. RESULTS: Of 50 monkeys fed with high-fat diet, 8 developed overt T2DM, 26 experienced impaired glucose tolerance and impaired fasting glucose, and FPG of 16 monkeys was normal. All monkeys with impaired glucose tolerance experienced obesity, compensatory increase of fasting plasma insulin, significant decline of postprandial glucose clearance rate (KGluc5-20), and decreased insulin secretion. CONCLUSIONS: In conclusion, rhesus monkey (M. m. lasiotis) has many similarities with human beings in terms of clinical manifestations and risk factors at different diabetes stages.