Severe oxidative stress in an acute inflammatory demyelinating model in the rhesus monkey

Oxidative stress is increasingly implicated as a co-factor of tissue injury in inflammatory/demyelinating disorders of the central nervous system (CNS), such as multiple sclerosis (MS). While rodent experimental autoimmune encephalomyelitis (EAE) models diverge from human demyelinating disorders with respect to limited oxidative injury, we observed that in a non-human primate (NHP) model for MS, namely EAE in the common marmoset, key pathological features of the disease were recapitulated, including oxidative tissue injury. Here, we investigated the presence of oxidative injury in another NHP EAE model, i.e. in rhesus macaques, which yields an acute demyelinating disease, which may more closely resemble acute disseminated encephalomyelitis (ADEM) than MS. Rhesus monkey EAE diverges from marmoset EAE by abundant neutrophil recruitment into the CNS and destructive injury to white matter. This difference prompted us to investigate to which extent the oxidative pathway features elicited in MS and marmoset EAE are reflected in the acute rhesus monkey EAE model. The rhesus EAE brain was characterized by widespread demyelination and active lesions containing numerous phagocytic cells and to a lesser extent T cells. We observed induction of the oxidative stress pathway, including injury, with a predilection of p22phox expression in neutrophils and macrophages/microglia. In addition, changes in iron were observed. These results indicate that pathogenic mechanisms in the rhesus EAE model may differ from the marmoset EAE and MS brain due to the neutrophil involvement, but may in the end lead to similar induction of oxidative stress and injury.</p

Lymphoid-Like Structures with Distinct B Cell Areas in Kidney Allografts are not Predictive for Graft Rejection. A Non-human Primate Study

Kidney allograft biopsies were analyzed for the presence of B cell clusters/aggregates using CD20 staining. Few B cells were found in the diffuse interstitial infiltrates, but clusters of B cells were found in nodular infiltrates. These nodular infiltrates were smaller shortly after transplantation, and their size increased over time. At the time of clinical rejection, the nodules often presented as tertiary lymphoid structures (TLS) with lymphoid-like follicles. The presence of small B cell clusters during the first 2 months after transplantation was not associated with early rejection. Even in animals that did not reject their allograft, TLS-like structures were present and could disappear over time. Although TLS were more often found in samples with interstitial fibrosis and tubular atrophy (IFTA), TLS were also present in samples without IFTA. The presence and density of clusters resembling tertiary lymphoid structures most likely reflect an ongoing immune response inside the graft and do not necessarily signify a poor graft outcome or IFTA

Involvement of the Red Nucleus in the Compensation of Parkinsonism may Explain why Primates can develop Stable Parkinson’s Disease

Neurological compensatory mechanisms help our brain to adjust to neurodegeneration as in Parkinson’s disease. It is suggested that the compensation of the damaged striato-thalamo-cortical circuit is focused on the intact thalamo-rubro-cerebellar pathway as seen during presymptomatic Parkinson, paradoxical movement and sensorimotor rhythm (SMR). Indeed, the size of the red nucleus, connecting the cerebellum with the cerebral cortex, is larger in Parkinson’s disease patients suggesting an increased activation of this brain area. Therefore, the red nucleus was examined in MPTP-induced parkinsonian marmoset monkeys during the presymptomatic stage and after SMR activation by neurofeedback training. We found a reverse significant correlation between the early expression of parkinsonian signs and the size of the parvocellular part of the red nucleus, which is predominantly present in human and non-human primates. In quadrupedal animals it consists mainly of the magnocellular part. Furthermore, SMR activation, that mitigated parkinsonian signs, further increased the size of the red nucleus in the marmoset monkey. This plasticity of the brain helps to compensate for dysfunctional movement control and can be a promising target for compensatory treatment with neurofeedback technology, vibrotactile stimulation or DBS in order to improve the quality of life for Parkinson’s disease patients

Involvement of the Red Nucleus in the Compensation of Parkinsonism may Explain why Primates can develop Stable Parkinson’s Disease

Neurological compensatory mechanisms help our brain to adjust to neurodegeneration as in Parkinson’s disease. It is suggested that the compensation of the damaged striato-thalamo-cortical circuit is focused on the intact thalamo-rubro-cerebellar pathway as seen during presymptomatic Parkinson, paradoxical movement and sensorimotor rhythm (SMR). Indeed, the size of the red nucleus, connecting the cerebellum with the cerebral cortex, is larger in Parkinson’s disease patients suggesting an increased activation of this brain area. Therefore, the red nucleus was examined in MPTP-induced parkinsonian marmoset monkeys during the presymptomatic stage and after SMR activation by neurofeedback training. We found a reverse significant correlation between the early expression of parkinsonian signs and the size of the parvocellular part of the red nucleus, which is predominantly present in human and non-human primates. In quadrupedal animals it consists mainly of the magnocellular part. Furthermore, SMR activation, that mitigated parkinsonian signs, further increased the size of the red nucleus in the marmoset monkey. This plasticity of the brain helps to compensate for dysfunctional movement control and can be a promising target for compensatory treatment with neurofeedback technology, vibrotactile stimulation or DBS in order to improve the quality of life for Parkinson’s disease patients

CNS histopathology.

<p>Shown is the occurrence (number of animals/total number of animals) of perivascular CD3⁺ cell, CD3+ and CD3⁺CD20⁺ (in brackets) clusters in the meninges and perivascular edema with CD68⁺ cells. Positive animals were identified as having several clusters containing >4 positive cells in more than one location.</p

Individual and Familial Susceptibility to MPTP in a Common Marmoset Model for Parkinson's Disease

INTRODUCTION: Insight into susceptibility mechanisms underlying Parkinson's disease (PD) would aid the understanding of disease etiology, enable target finding and benefit the development of more refined disease-modifying strategies. METHODS: We used intermittent low-dose MPTP (0.5 mg/kg/week) injections in marmosets and measured multiple behavioral and neurochemical parameters. Genetically diverse monkeys from different breeding families were selected to investigate inter- and intrafamily differences in susceptibility to MPTP treatment. RESULTS: We show that such differences exist in clinical signs, in particular nonmotor PD-related behaviors, and that they are accompanied by differences in neurotransmitter levels. In line with the contribution of a genetic component, different susceptibility phenotypes could be traced back through genealogy to individuals of the different families. CONCLUSION: Our findings show that low-dose MPTP treatment in marmosets represents a clinically relevant PD model, with a window of opportunity to examine the onset of the disease, allowing the detection of individual variability in disease susceptibility, which may be of relevance for the diagnosis and treatment of PD in humans

Rhesus monkeys display a naturally occurring cellular immune status against B-LCL.

<p>A) PBMC proliferate <i>ex vivo</i> when cultured with autologous B-LCL (n = 9). The response increased from 835±288 cpm to 16920±3076 cpm (P = 0.0039; Wilcoxon matched pairs test). B) A representative example (animal A4) of the phenotype of proliferating T-cells (percentage cells that have diluted CFSE) present in the natural repertoire proliferating <i>ex vivo</i> against B-LCL. Solid histograms show proliferation in the absence of B-LCL, black lines show proliferation in the presence of B-LCL. C) Mean CFSE dilution in the absence of B-LCL (n = 15; black bars) and in the presence of B-LCL (n = 9). Consistent with the literature on EBV, these are CD3⁺CD8⁺ (regular CTL) and CD3⁻CD56⁺ (NK). Interestingly, also CD3⁺CD8⁺CD56⁺ T-cells proliferate, which are presumably NK-CTL, a subtype that is of interest for the EAE model <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071549#pone.0071549-Kap1" target="_blank">[18]</a>.</p

Systemic effects of B-LCL infusion.

<p>B-LCL were infused on days 0, 28 and 56. On day 98 animals from groups A (MOG_34–56) and B (CMVmcp_981–1003) were immunized with MOG_34–56 in Incomplete Freund’s adjuvant (IFA). (A) The infusion of autologous B-LCL induces transient increment of circulating lymphocytes. For normalization purposes lymphocyte numbers were expressed relative to day 0 (mean ± SEM 1.8±0.3; 2.4±0.4 and 2.0±0.3×10⁹/l for groups A, B and C respectively, which is not significantly different from each other, P = 0.2184). The increases in numbers of circulating lymphocytes vastly exceeded the number of infused B-LCL. (B) The <i>ex vivo</i> proliferation of unstimulated PBMC was persistently increased after the first B-LCL injection. No significant differences were observed between groups (P = 0.2299). (C) The bodyweights were normalized against the day-0 bodyweights. Bodyweight loss is observed from day 70 onwards, up to 15% in some animals.</p

In vivo expansion of T-cells.

<p>Percentages of CD4⁺ T-cells and CD8⁺ T-cells in PBMC, expressed as a percentage of day 0, demonstrate that mainly the CD8⁺ subpopulation is expanded after the infusion of B-LCL, which is consistent with the data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071549#pone-0071549-g001" target="_blank">Figure 1</a>. Percentages of CD4⁺ T-cells on day 0 were: 35.7±11.2; 36.8±9.8 and 29.5±19% for groups A, B and C respectively, which is not significantly different from each other (P = 0.4677). Percentages of CD8⁺ T-cells on day 0 were: 18.4±3.5; 21.2±5.2 and 10.2±2.5% for groups A, B and C respectively (P = 0.1451). Consistent with our published data in rhesus monkeys <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071549#pone.0071549-Brok1" target="_blank">[17]</a> an expansion of both CD4⁺ and CD8⁺ T-cells was observed after a booster with MOG_34–56 in IFA.</p

Histological features induced with cMOG_34–56-pulsed B-LCL (group C).

<p>Indicated beneath each panel is the animal and the staining displayed in the respective panel. In all monkeys from group C and in some monkeys from groups A and B perivascular cuffs of infiltrated CD3⁺ T-cells could be found, an example of which is given in panel A. Diffuse infiltrates of CD3⁺ T-cells were more rarely found (B). Only in 3 monkeys lesions of relatively large size were found (C, D and E). (C) Shown is one lesion with PLP staining (C1) with infiltrated CD68⁺ macrophages (C2). The laminin staining in D2 shows that the macrophages remain confined to the Virchow Rubin space and do not pass the glia limitans. The inserts to C2 and D3 show the typical CD68 staining pattern we found. Infiltrates of CD3⁺ and CD20⁺ cells were also found in the meninges, where the two cell types seemed to co-localize (F1, F2). In monkey C4, in which the largest lesions were found, we observed some areas of myelin degeneration (G). It is unclear whether this represents the start of demyelination.</p