Rapid protection induced by a single-shot Lassa vaccine in male cynomolgus monkeys.

Lassa fever hits West African countries annually in the absence of licensed vaccine to limit the burden of this viral hemorrhagic fever. We previously developed MeV-NP, a single-shot vaccine protecting cynomolgus monkeys against divergent strains one month or more than a year before Lassa virus infection. Given the limited dissemination area during outbreaks and the risk of nosocomial transmission, a vaccine inducing rapid protection could be useful to protect exposed people during outbreaks in the absence of preventive vaccination. Here, we test whether the time to protection can be reduced after immunization by challenging measles virus pre-immune male cynomolgus monkeys sixteen or eight days after a single shot of MeV-NP. None of the immunized monkeys develop disease and they rapidly control viral replication. Animals immunized eight days before the challenge are the best controllers, producing a strong CD8 T-cell response against the viral glycoprotein. A group of animals was also vaccinated one hour after the challenge, but was not protected and succumbed to the disease as the control animals. This study demonstrates that MeV-NP can induce a rapid protective immune response against Lassa fever in the presence of MeV pre-existing immunity but can likely not be used as therapeutic vaccine.

Protective effects of the imidazoline-like drug lnp599 in a marmoset model of obesity-induced metabolic disorders.

BACKGROUND/OBJECTIVES: Overweight and obesity are undoubtable risk factors for type 2 diabetes and cardiovascular diseases and significantly contribute to the global morbi-mortality. We previoulsy reported that LNP599, a pharmacological imidazoline-like activator of hepatic AMPK/adiponectin signaling, protects against the development of adiposity and obesity and the associated cardio-metabolic disorders, suggesting that it may be a suitable drug candidate for a therapeutic approach targeting the development of obesity at very early stages. The objective of the present study was to evaluate the metabolic effects of LNP599 in a model of diet-induced overweight and metabolic disorders in a nonhuman primate, the common marmoset (Callithrix jacchus), and more particularly to establish the impact of the compound on cholesterol homeostasis, i.e., HDL and LDL/VLDL lipoproteins. METHODS: Marmosets were fed normal (NC) or hypercaloric (HC) chow during 16 weeks. Diet-induced changes in body weight and metabolism were assessed. Effects of LNP599 were evaluated in a subset of HC animals (HC-LNP) receiving the compound at a daily dose of 10 mg/kg over the 16 weeks. RESULTS: HC-feeding induced significant overweight associated with a marked dyslipidemia (hypertriglyceridemia, hypercholesterolemia, and reduced HDL over LDL/VLDL cholesterol ratio). LNP599 blunted the diet-induced body weight gain and largely protected against the development of hypertriglyceridemia. Total cholesterol was unchanged but the ratio of HDL over LDL/VLDL cholesterol was more than doubled. CONCLUSIONS: The profile of metabolic troubles obtained upon enriched diet mimicked the disorders associated with spontaneous obesity in marmosets. HC marmosets represent an experimental model of high clinical relevance to study the pathophysiology of obesity and related dyslipidemia and to evaluate the effects of emerging therapies targeting these disorders. Our data confirm the preventing effects of LNP599 in a nonhuman primate model and demonstrate for the first time the high potency of this drug in promoting HDL-cholesterol.

Publisher Correction: Lipidome determinants of maximal lifespan in mammals.

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Cestode infections in non-human primates suggest the existence of zoonotic cycles in the area surrounding the Strasbourg primatology center.

BACKGROUND: Several cases of infections due to Echinococcus multilocularis, Taenia martis and Taenia crassiceps were recently described in various species of captive non-human primates (NHPs) harbored in the Strasbourg Primate Center (SPC). Furthermore, one of the first cases of human cysticercosis due to T. martis was described in the Strasbourg region. These data suggest the existence of zoonotic cycles of tapeworm infections in the direct environment of the SPC. The aim of our study was to assess the prevalence of larval cestode infections among intermediate and definitive hosts in the close neighborhood of the center. We analyzed carnivore mammal fecal samples as well as rodent carcasses, collected inside or near the SPC, using PCR. Furthermore, we performed serology for Echinococcus spp. and Taenia spp. on NHP sera. RESULTS: We found that 14.5% (95% CI [8.6; 20.4]) of 138 carnivore feces were positive for E. multilocularis-DNA, as well as 25% (95% CI [5.5; 57.2]) of 12 rodent carcasses, and 5.1% (95% CI [1.4; 8.7]) for T. martis or T. crassiceps. Of all NHPs tested, 10.1% (95% CI [3.8; 16.4]) were seropositive for Echinococcus spp. and 8.2% (95% CI [1.3; 15.1]) for Taenia spp. CONCLUSIONS: Our data support the existence of zoonotic cycles of larval cestode infections in the direct environment of the primatology center affecting NHPs harbored in the SPC, potentially threatening the human population living in this area. Since this zoonotic risk is borne by local wildlife, and given the severity of these infections, it seems necessary to put in place measures to protect captive NHPs, and further studies to better assess the risk to human populations.

Evaluation of a new balloon for fetal endoscopic tracheal occlusion in the nonhuman primate model.

OBJECTIVE: We developed a new balloon called "Smart-TO," which allows noninvasive and easy unplugging, thanks to a magnetic valve actuated by the magnetic fringe field of a magnetic resonance imaging (MRI) scanner. The objective of this feasibility study was to evaluate the operation of this new balloon in a nonhuman primate model. METHODS: Four pregnant rhesus monkeys underwent fetal endoscopic tracheal occlusion using the "Smart-TO" balloon. The pregnant monkeys were simply carried around the perimeter of an MRI scanner a few days later. Study outcomes were feasibility of fetal tracheal occlusion using the "Smart-TO" balloon, persistence of the balloon in the fetal trachea, and deflation of the balloon when subjected to the magnetic fringe field of an MRI. RESULTS: At the time of the unplug procedure, in all cases, the balloon was still in a correct position, and its shape did not change based on their ultrasound appearance. After bringing the pregnant monkeys into the fringe field of the MRI scanner, the balloon deflated in all cases. CONCLUSION: The balloon we developed allows noninvasive, easily triggered, and externally controlled reversal occlusion, based on the nonhuman primate model. Further tests evaluating occlusiveness and potential adverse effects are necessary.

Lipidome determinants of maximal lifespan in mammals.

Maximal lifespan of mammalian species, even if closely related, may differ more than 10-fold, however the nature of the mechanisms that determine this variability is unresolved. Here, we assess the relationship between maximal lifespan duration and concentrations of more than 20,000 lipid compounds, measured in 669 tissue samples from 6 tissues of 35 species representing three mammalian clades: primates, rodents and bats. We identify lipids associated with species' longevity across the three clades, uncoupled from other parameters, such as basal metabolic rate, body size, or body temperature. These lipids clustered in specific lipid classes and pathways, and enzymes linked to them display signatures of greater stabilizing selection in long-living species, and cluster in functional groups related to signaling and protein-modification processes. These findings point towards the existence of defined molecular mechanisms underlying variation in maximal lifespan among mammals.

Description of vertebral and liver alveolar echinococcosis cases in Cynomolgus monkeys (Macaca fascicularis).

BACKGROUND: Echinococcus multilocularis, the causative agent of alveolar echinococcosis, is a fox tapeworm widely distributed in Europe with an increase of endemic area in recent years. Many mammal species including humans and non-human primates can be infected by accidental ingestion of eggs. CASE PRESENTATION: In March 2011, a 5-year-old zoo-raised male cynomolgus macaque (Macaca fascicularis) presented a paresis of the lower limbs which evolved into paralysis. Lesions in liver and vertebra were observed on tomography scan. E. multilocularis infection was diagnosed post-mortem by morphological and histological examination and detection of Em DNA by polymerase chain reaction. Serodiagnosis of other primates of the colony using enzyme-linked immunosorbent assay (ELISA) was negative. In June 2013, at necroscopy, a hepatic and a paravertebral masses were detected in a second cynomolgus macaque of the same colony. Serology and DNA isolated from hepatic and abdominal cysts confirmed E. multilocularis infection. CONCLUSIONS: We described hear vertebral and liver localization of alveolar echinococcosis in non-human primates. The animals lived in an indoor/outdoor housing facility, where the probable mode of contamination is by ingestion of food foraging around the enclosure which could be contaminated with fox feces. Serological survey in the facility should allow us to estimate the risk of human contamination and the zoonotic risk of monkey infection due to environmental contamination.

Experimental fetal endoscopic tracheal occlusion in rhesus and cynomolgus monkeys: nonhuman primate models.

OBJECTIVE: The monkey model is the best model to investigate some physiological response to the fetal transitory tracheal occlusion but it has never been described in Macaca monkeys. The aim of this study was to evaluate the feasibility of fetal endoscopic tracheal occlusion (FETO) in a non-human primate model. METHODS: Pregnant rhesus monkeys and cynomolgus were tested as a potential experimental model for FETO in the third trimester of pregnancy, by performing fetal tracheoscopies with and without tracheal occlusion. RESULTS: A total of 22 pregnancies were followed in 16 monkeys and underwent fetal surgery. Percutaneous endoscopic access to the uterine cavity was possible in 20 cases (91%). Of these 20 pregnant monkeys, fetal tracheoscopy could be achieved in 15 cases (75%). In rhesus monkeys, the time between the onset of endoscopy and tracheal penetration decreases as operator experience increases. Neither maternal morbidity nor mortality was related to surgery. Two fetal losses were possibly due to the procedure. CONCLUSION: FETO is feasible in the non-human primate, which closely reflects procedures in humans. The non-human primate model for FETO, specially the rhesus monkeys, may be useful for future studies concerning the mechanisms related to the lung growth after transitory fetal tracheal occlusion.

First case of peritoneal cysticercosis in a non-human primate host (Macaca tonkeana) due to Taenia martis.

BACKGROUND: Infections with larval stages (metacestodes) of a variety of taeniid species have been described in primates, including humans, with partial to severe clinical consequences. Taenia martis is a tapeworm of mustelids, and martens are mainly their definitive hosts in Central Europe. In the rodent intermediate host cysticerci develop in the pleural and peritoneal cavities. The present report describes a case of T. martis peritoneal cysticercosis in a Tonkean macaque. FINDINGS: An abdominal mass was detected in a 3-year-old male Tonkean macaque (Macaca tonkeana) born and raised in a primate colony in France. Examination of the mass after laparotomy showed numerous vesicles identified as cysticerci of T. martis, based on the morphology of scolex and hooks, with confirmation by PCR amplification and sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes. Exeresis of the lesion was not possible and praziquantel (5.7 mg/kg) was given twice at an interval of 3 days. The abdominal mass was greatly diminished upon examination 2 months later and no signs of recurrence were noticed during the following 4 years. CONCLUSIONS: This is the first report of T. martis cysticercosis in a monkey. This record and the recent first description of an ocular T. martis cysticercosis in a human show the susceptibility of primates to T. martis and its zoonotic potential. This taeniid species must be considered in the differential diagnosis of cysticercosis in primates.

Characterization of the 9L gliosarcoma implanted in the Fischer rat: an orthotopic model for a grade IV brain tumor.

Among rodent models for brain tumors, the 9L gliosarcoma is one of the most widely used. Our 9L-European Synchrotron Radiation Facility (ESRF) model was developed from cells acquired at the Brookhaven National Laboratory (NY, USA) in 1997 and implanted in the right caudate nucleus of syngeneic Fisher rats. It has been largely used by the user community of the ESRF during the last decade, for imaging, radiotherapy, and chemotherapy, including innovative treatments based on particular irradiation techniques and/or use of new drugs. This work presents a detailed study of its characteristics, assessed by magnetic resonance imaging (MRI), histology, immunohistochemistry, and cytogenetic analysis. The data used for this work were from rats sampled in six experiments carried out over a 3-year period in our lab (total number of rats = 142). The 9L-ESRF tumors were induced by a stereotactic inoculation of 10(4) 9L cells in the right caudate nucleus of the brain. The assessment of vascular parameters was performed by MRI (blood volume fraction and vascular size index) and by immunostaining of vessels (rat endothelial cell antigen-1 and type IV collagen). Immunohistochemistry and regular histology were used to describe features such as tumor cell infiltration, necrosis area, nuclear pleomorphism, cellularity, mitotic characteristics, leukocytic infiltration, proliferation, and inflammation. Moreover, for each of the six experiments, the survival of the animals was assessed and related to the tumor growth observed by MRI or histology. Additionally, the cytogenetic status of the 9L cells used at ESRF lab was investigated by comparative genomics hybridization analysis. Finally, the response of the 9L-ESRF tumor to radiotherapy was estimated by plotting the survival curves after irradiation. The median survival time of 9L-ESRF tumor-bearing rats was highly reproducible (19-20 days). The 9L-ESRF tumors presented a quasi-exponential growth, were highly vascularized with a high cellular density and a high proliferative index, accompanied by signs of inflammatory responses. We also report an infiltrative pattern which is poorly observed on conventional 9 L tumor. The 9L-ESRF cells presented some cytogenetic specificities such as altered regions including CDK4, CDKN2A, CDKN2B, and MDM2 genes. Finally, the lifespan of 9L-ESRF tumor-bearing rats was enhanced up to 28, 35, and 45 days for single doses of 10, 20, and 2 × 20 Gy, respectively. First, this report describes an animal model that is used worldwide. Second, we describe few features typical of our model if compared to other 9L models worldwide. Altogether, the 9L-ESRF tumor model presents characteristics close to the human high-grade gliomas such as high proliferative capability, high vascularization and a high infiltrative pattern. Its response to radiotherapy demonstrates its potential as a tool for innovative radiotherapy protocols.

Enhancement of survival of 9L gliosarcoma bearing rats following intracerebral delivery of drugs in combination with microbeam radiation therapy.

Microbeam radiation therapy (MRT) is a form of radiosurgery first dedicated to the treatment of brain tumors. It uses arrays of synchrotron generated X-rays microbeams of very high doses (typically 625 Gy). Microbeams are typically few micrometers large (25 microm) and few hundred micrometers spaced (200 microm). Previous experiments have shown that despite a good tumor eradication rate (5/11), a 100-microm spacing unidirectional irradiation (skin dose 625 Gy, width 25 microm) was too invasive for normal tissue. On the contrary, a 200-microm spacing unidirectional irradiation preserved healthy tissue with a low tumor eradication rate (2/32). The purpose of this study was to enhance the potential of the 200 microm spacing irradiation protocol. After diagnosis of the tumor by MRI, 9L tumor-bearing rats were laterally irradiated with 51 microbeams (625 Gy, 25 microm, 200 microm) 14 days after implantation. Three drugs (Gd-DTPA, CisPt, temozolomide) were tested, after intratumoral injection at the theoretical center of the tumor. Control rats displayed a median survival time of 19 days. There was no significant difference between drug-treated rats and control group. Irradiated animals showed an increase in life span (ILS) of 60.5%. Interestingly, the ILS increased to 131.6% and 1/6 rat survived more than 1 year in case of MRT combined with gadolinium injection. These results showed that the synergy between gadolinium injection (acting as a dose enhancer) and MRT improved significantly the life span of tumor bearing rats (more than a factor 2).

Irradiation of intracerebral 9L gliosarcoma by a single array of microplanar x-ray beams from a synchrotron: balance between curing and sparing.

The purpose of this work was the understanding of microbeam radiation therapy at the ESRF in order to find the best compromise between curing of tumors and sparing of normal tissues, to obtain a better understanding of survival curves and to report its efficiency. This method uses synchrotron-generated x-ray microbeams. Rats were implanted with 9L gliosarcomas and the tumors were diagnosed by MRI. They were irradiated 14 days after implantation by arrays of 25 microm wide microbeams in unidirectional mode, with a skin entrance dose of 625 Gy. The effect of using 200 or 100 microm center-to-center spacing between the microbeams was compared. The median survival time (post-implantation) was 40 and 67 days at 200 and 100 microm spacing, respectively. However, 72% of rats irradiated at 100 microm spacing showed abnormal clinical signs and weight patterns, whereas only 12% of rats were affected at 200 microm spacing. In parallel, histological lesions of the normal brain were found in the 100 microm series only. Although the increase in lifespan was equal to 273% and 102% for the 100 and 200 microm series, respectively, the 200 microm spacing protocol provides a better sparing of healthy tissue and may prove useful in combination with other radiation modalities or additional drugs.