Subthalamic Deep Brain Stimulation Affects Plasma Corticosterone Concentration and Peripheral Immunity Changes in Rat Model of Parkinson's Disease

Deep brain stimulation of the subthalamic nucleus (DBS-STN) is an effective treatment for advanced motor symptoms of Parkinson's disease (PD). Recently, a connection between the limbic part of the STN and side effects of DBS-STN has been increasingly recognized. Animal studies have shown that DBS-STN influences behavior and provokes neurochemical changes in regions of the limbic system. Some of these regions, which are activated during DBS-STN, are involved in neuroimmunomodulation. The therapeutic effects of DBS-STN in PD treatment are clear, but the influence of DBS-STN on peripheral immunity has not been reported so far. In this study, we examined the effects of unilateral DBS-STN applied in male Wistar rats with 6-hydroxydopamine PD model (DBS-6OHDA) and rats without nigral dopamine depletion (DBS) on corticosterone (CORT) plasma concentration, blood natural killer cell cytotoxicity (NKCC), leukocyte numbers, lymphocyte population and apoptosis numbers, plasma interferon gamma (IFN-γ), interleukin 6 (IL-6), and tumor necrosis factor (TNF-α) concentration. The same peripheral immune parameters we measured also in non-stimulated rats with PD model (6OHDA). We observed peripheral immunity changes related to PD model. The NKCC and percentage of T cytotoxic lymphocytes were enhanced, while the level of lymphocyte apoptosis was down regulated in 6OHDA and DBS-6OHDA groups. After DBS-STN (DBS-6OHDA and DBS groups), the plasma CORT and TNF-α were elevated, the number of NK cells and percentage of apoptosis were increased, while the number of B lymphocytes was decreased. We also found, changes in plasma IFN-γ and IL-6 levels in all the groups. These results suggest potential peripheral immunomodulative effects of DBS-STN in the rat model of PD. However, further studies are necessary to explain these findings and their clinical implication. Graphical Abstract Influence of deep brain stimulation of the subthalamic nucleus on peripheral immunity in rat model of Parkinson's disease.

The impact of dextran sodium sulphate and probiotic pre-treatment in a murine model of Parkinson's disease

BACKGROUND

Recent work has established that Parkinson's disease (PD) patients have an altered gut microbiome, along with signs of intestinal inflammation. This could help explain the high degree of gastric disturbances in PD patients, as well as potentially be linked to the migration of peripheral inflammatory factors into the brain. To our knowledge, this is the first study to examine microbiome alteration prior to the induction of a PD murine model.

METHODS

We presently assessed whether pre-treatment with the probiotic, VSL #3, or the inflammatory inducer, dextran sodium sulphate (DSS), would influence the PD-like pathology provoked by a dual hit toxin model using lipopolysaccharide (LPS) and paraquat exposure.

RESULTS

While VSL #3 has been reported to have anti-inflammatory effects, DSS is often used as a model of colitis because of the gut inflammation and the breach of the intestinal barrier that it induces. We found that VSL#3 did not have any significant effects (beyond a blunting of LPS paraquat-induced weight loss). However, the DSS treatment caused marked changes in the gut microbiome and was also associated with augmented behavioral and inflammatory outcomes. In fact, DSS markedly increased taxa belonging to the Bacteroidaceae and Porphyromonadaceae families but reduced those from Rikencellaceae and S24-7, as well as provoking colonic pro-inflammatory cytokine expression, consistent with an inflamed gut. The DSS also increased the impact of LPS plus paraquat upon microglial morphology, along with circulating lipocalin-2 (neutrophil marker) and IL-6. Yet, neither DSS nor VSL#3 influenced the loss of substantia nigra dopamine neurons or the astrocytic and cytoskeleton remodeling protein changes that were provoked by the LPS followed by paraquat treatment.

CONCLUSIONS

These data suggest that disruption of the intestinal integrity and the associated microbiome can interact with systemic inflammatory events to promote widespread brain-gut changes that could be relevant for PD and at the very least, suggestive of novel neuro-immune communication.

Do cross-reactive antibodies cause neuropathology in COVID-19?

Neurological symptoms are seen in patients with COVID-19 and can persist or re-emerge after clearance of SARS-CoV-2. Recent findings suggest that antibodies to SARS-CoV-2 can cross-react with mammalian proteins. Focusing on neurological symptoms, we discuss whether these cross-reactive antibodies could contribute to COVID-19 disease pathology and to the persistence of symptoms in patients who have cleared the initial viral infection.

Neurological symptoms are increasingly being observed in patients with COVID-19; this Comment article considers whether cross-reactive antibodies might contribute to the pathology associated with SARS-CoV-2 infection.

Calpain mediated expansion of CD4+ cytotoxic T cells in rodent models of Parkinson's disease

Parkinson's disease (PD), a debilitating progressive degenerative movement disorder associated with loss of dopaminergic (DA) neurons in the substantia nigra (SN), afflicts approximately one million people in the U.S., including a significant number of Veterans. Disease characteristics include tremor, rigidity, postural instability, bradykinesia, and at a cellular level, glial cell activation and Lewy body inclusions in DA neurons. The most potent medical/surgical treatments do not ultimately prevent disease progression. Therefore, new therapies must be developed to halt progression of the disease. While the mechanisms of the degenerative process in PD remain elusive, chronic inflammation, a common factor in many neurodegenerative diseases, has been implicated with associated accumulation of toxic aggregated α-synuclein in neurons. Calpain, a calcium-activated cysteine neutral protease, plays a pivotal role in SN and spinal cord degeneration in PD via its role in α-synuclein aggregation, activation/migration of microglia and T cells, and upregulation of inflammatory processes. Here we report an increased expression of a subset of CD4+ T cells in rodent models of PD, including MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mice and DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride]/6-hydroxydopamine rats, which produced higher levels of perforin and granzyme B - typically found in cytotoxic T cells. Importantly, the CD4+ cytotoxic subtype was attenuated following calpain inhibition in MPTP mice, suggesting that calpain and this distinct CD4+ T cell subset may have critical roles in the inflammatory process, disease progression, and neurodegeneration in PD.

Rosmarinic acid attenuates inflammatory responses through inhibiting HMGB1/TLR4/NF-κB signaling pathway in a mouse model of Parkinson's disease

Inflammation contributes to the pathological processes in patients and animal models of PD. Rosmarinic acid (RA) has been demonstrated to protect neurons in PD models. The present study aimed to evaluate the anti-inflammatory effect of RA on PD and reveal possible pharmacological mechanisms. 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) was injected to mice to establish PD model in vivo. BV-2 cells were exposed to 1-methyl-4-phenylpyridinium (MPP+) and α-synuclein to establish PD model in vitro. Results showed that treatment with RA dose-dependently improved motor function of PD mice, increased the number of tyrosine hydroxylase-positive cells, reduced production of pro-inflammatory cytokines, and inhibited microglia activation in ventral midbrain. In cell study, RA also decreased MPP+ or α-synuclein-induced secretion of pro-inflammatory cytokines. Furthermore, RA treatment downregulated the expression levels of HMGB1, TLR4 and Myd88 and inhibited NF-κB nuclear expression both in PD animal and cell models. These findings indicated that RA could attenuate inflammatory responses through suppressing HMGB1/TLR4/NF-κB signaling pathway, which may contribute to its anti-PD activity.

Expanding spectrum of contactin-associated protein 2 (CASPR2) autoimmunity-syndrome of parkinsonism and ataxia

Contactin-associated protein 2 (CASPR2) antibodies are originally associated with Morvan's syndrome and peripheral nerve hyper excitability. Our objective was to study retrospectively the clinical spectrum of CASPR2 antibody-positive patients in our hospital. This is a retrospective observational study. Patients treated at the Amrita Institute of Medical Sciences from May 2013 to April 2016, who were tested positive for CASPR2 antibodies, were included. A total of 1584 samples were tested in the neuroimmunology laboratory during the study period for voltage-gated potassium channel (VGKC) complex antibodies-leucine-rich glioma-inactivated protein 1 (LGI1) and CASPR2 antibodies. Thirty-four were positive for LGI1, 13 were positive for CASPR2, and 7 were for both (total 54-3.4% positivity). Of these 54 cases, 11 were treated in our hospital. Seven were positive for LGI1, three for CASPR2, and one for both. The patient who had both CASPR2 and LGI1 antibody positive had Morvan's syndrome. One patient with CASPR2 had neuromyotonia. The other patient was admitted with status epilepticus with a syndrome of parkinsonism and ataxia. The third patient had encephalopathy and myoclonus with a syndrome of parkinsonism and ataxia. Two of them underwent siddha treatment for other ailments prior to the onset of the disease for other ailments. Our short series shows the expanding spectrum of CASPR2 autoimmunity. Syndrome of parkinsonism and ataxia is an important manifestation of CASPR2 autoimmunity where we can offer a definitive treatment.

Differential effects of immunotherapy with antibodies targeting α-synuclein oligomers and fibrils in a transgenic model of synucleinopathy

Disorders with progressive accumulation of α-synuclein (α-syn) are a common cause of dementia and parkinsonism in the aging population. Accumulation and propagation of α-syn play a role in the pathogenesis of these disorders. Previous studies have shown that immunization with antibodies that recognize C-terminus of α-syn reduces the intra-neuronal accumulation of α-syn and related deficits in transgenic models of synucleinopathy. These studies employed antibodies that recognize epitopes within monomeric and aggregated α-syn that were generated through active immunization or administered via passive immunization. However, it is possible that more specific effects might be achieved with antibodies recognizing selective species of the α-syn aggregates. In this respect we recently developed antibodies that differentially recognized various oligomers (Syn-O1, -O2, and -O4) and fibrilar (Syn-F1 and -F2) forms of α-syn. For this purpose wild-type α-syn transgenic (line 61) mice were immunized with these 5 different antibodies and neuropathologically and biochemically analyzed to determine which was most effective at reducing α-syn accumulation and related deficits. We found that Syn-O1, -O4 and -F1 antibodies were most effective at reducing accumulation of α-syn oligomers in multiple brain regions and at preventing neurodegeneration. Together this study supports the notion that selective antibodies against α-syn might be suitable for development new treatments for synucleinopathies such as PD and DLB.

Manganese-Enhanced Magnetic Resonance Imaging for Detection of Vasoactive Intestinal Peptide Receptor 2 Agonist Therapy in a Model of Parkinson's Disease

Neuroprotective immunity is defined by transformation of T-cell polarity for therapeutic gain. For neurodegenerative disorders and specifically for Parkinson's disease (PD), granulocyte-macrophage colony stimulating factor or vasoactive intestinal peptide receptor 2 (VIPR2) agonists elicit robust anti-inflammatory microglial responses leading to neuronal sparing in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. While neurotherapeutic potential was demonstrated for PD, there remain inherent limitations in translating these inventions from the laboratory to patients. One obstacle in translating such novel neurotherapeutics centers on the availability of suitable noninvasive methods to track disease progression and therapeutic efficacy. To this end, we developed manganese-enhanced magnetic resonance imaging (MEMRI) assays as a way to track a linkage between glial activation and VIPR2 agonist (LBT-3627)-induced neuroprotective immunity for MPTP-induced nigrostriatal degeneration. Notably, LBT-3627-treated, MPTP-intoxicated mice show reduced MEMRI brain signal intensities. These changes paralleled reduced astrogliosis and resulted in sparing of nigral tyrosine hydroxylase neurons. Most importantly, the data suggest that MEMRI can be developed as a biomarker tool to monitor neurotherapeutic responses that are relevant to common neurodegenerative disorders used to improve disease outcomes.

Amniotic fluid stem cells with low γ-interferon response showed behavioral improvement in Parkinsonism rat model

Amniotic fluid stem cells (AFSCs) are multipotent stem cells that may be used in transplantation medicine. In this study, AFSCs established from amniocentesis were characterized on the basis of surface marker expression and differentiation potential. To further investigate the properties of AFSCs for translational applications, we examined the cell surface expression of human leukocyte antigens (HLA) of these cells and estimated the therapeutic effect of AFSCs in parkinsonian rats. The expression profiles of HLA-II and transcription factors were compared between AFSCs and bone marrow-derived mesenchymal stem cells (BMMSCs) following treatment with γ-IFN. We found that stimulation of AFSCs with γ-IFN prompted only a slight increase in the expression of HLA-Ia and HLA-E, and the rare HLA-II expression could also be observed in most AFSCs samples. Consequently, the expression of CIITA and RFX5 was weakly induced by γ-IFN stimulation of AFSCs compared to that of BMMSCs. In the transplantation test, Sprague Dawley rats with 6-hydroxydopamine lesioning of the substantia nigra were used as a parkinsonian-animal model. Following the negative γ-IFN response AFSCs injection, apomorphine-induced rotation was reduced by 75% in AFSCs engrafted parkinsonian rats but was increased by 53% in the control group after 12-weeks post-transplantation. The implanted AFSCs were viable, and were able to migrate into the brain’s circuitry and express specific proteins of dopamine neurons, such as tyrosine hydroxylase and dopamine transporter. In conclusion, the relative insensitivity AFSCs to γ-IFN implies that AFSCs might have immune-tolerance in γ-IFN inflammatory conditions. Furthermore, the effective improvement of AFSCs transplantation for apomorphine-induced rotation paves the way for the clinical application in parkinsonian therapy.

[Future drug targets for Parkinson's disease]

Parkinson's disease is characterized by a triad of cardinal motor symptoms (bradykinesia, rigidity and tremor) resulting from the loss of dopaminergic neurons in the substantia nigra. This synucleinopathy is classified in the larger group of Lewy body disorders. Currently, these symptoms are relatively well alleviated by drugs that restore dopaminergic neurotransmission, andlor by deep brain stimulation. It is not yet possible to halt the underlying degeneration, or to treat symptoms due to non-dopaminergic neuron damage. This review examines the mechanisms of neuronal degeneration in Parkinson's disease, new targets for neuroprotection, and the mechanisms causing symptoms resistant to current treatments.

MPTP-induced neuroinflammation increases the expression of pro-inflammatory cytokines and their receptors in mouse brain

Parkinson's disease (PD) is a common neurodegenerative disease characterised by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra (SN). Despite intensive research, the cause of neuronal loss in PD is poorly understood. Inflammatory mechanisms have been implicated in the pathophysiology of PD. In this study, conducted on an experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model, we investigated the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6 and their receptors (IL-1RI, TNF-αRI, IL-6Rα) at the SN and caudate-putamen (CP) levels. In MPTP-treated animals we observed a significant increase in IL-1β, TNF-α and IL-6 mRNA expression levels both in the SN and CP in comparison with untreated mice. In addition, both mRNA and protein levels of IL-1RI, TNF-αRI and IL-6Rα were significantly enhanced in the SN of MPTP-treated mice in comparison to controls, whereas no significant differences were observed in the CP between treated and untreated mice. Overall, these results indicate a role of both pro-inflammatory cytokines and their receptors in the pathogenesis of PD.

Exendin-4 protects dopaminergic neurons by inhibition of microglial activation and matrix metalloproteinase-3 expression in an animal model of Parkinson's disease

Exendin-4 is a naturally occurring more potent and stable analog of glucagon-like peptide-1 (GLP-1) that selectively binds at the GLP-1 receptor. It has been recently demonstrated that GLP-1 receptor stimulation preserves dopaminergic neurons in cellular and rodent models of Parkinson's disease (PD). 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes nigrostriatal dopaminergic neurotoxicity in rodents; previous studies suggest that activated microglia actively participate in the pathogenesis of PD neurodegeneration. However, the role of microglia in the neuroprotective properties of exendin-4 is still unknown. Here, we show that, in the mouse MPTP PD model, systemic administration of exendin-4 significantly attenuates the loss of substantia nigra pars compacta (SNpc) neurons and the striatal dopaminergic fibers. Exendin-4 prevents MPTP-induced microglial activation in the SNpc and striatum, and the expression of matrix metalloproteinase-3. In addition, exendin-4 also suppressed MPTP-induced expression of pro-inflammatory molecules and tumor necrosis factor alpha and interleukin-1 beta. Our data indicate that exendin-4 may act as a survival factor for dopaminergic neurons by functioning as a microglia-deactivating factor and suggest that exendin-4 may be a valuable therapeutic agent for neurodegenerative diseases such as PD.

Neuroinflammation in the pathophysiology of Parkinson's disease: evidence from animal models to human in vivo studies with [11C]-PK11195 PET

Increasing evidence suggests that neuroinflammation is an active process in Parkinson's disease (PD) that contributes to ongoing neurodegeneration. PD brains and experimental PD models show elevated cytokine levels and up-regulation of inflammatory-associated factors as cyclo-oxygenase-2 and inducible nitric oxide oxidase. Antiinflammatory treatment reduced neuronal degeneration in experimental models. In this review, we summarize the place of neuroinflammation in the pathophysiology of PD. In vivo PET studies are discussed. These methods provide a means to monitor in vivo potential clinical relevance of antiinflammatory treatment strategies in PD.

Effect of transplantation of c17.2 cells transfected with interleukin-10 gene on intracerebral immune response in rat model of Parkinson's disease

Currently, regulation of immune response after grafting has become a hot topic in Parkinson's disease (PD) transplantation research. Interleukin-10 (IL-10) is an important regulator of immune system. Presently, we transplanted c17.2 neural stem cells transfected with pcDNA3.1-Hygro-IL-10 vector (IL-10-c17.2 cells) or Mock-c17.2 cells (c17.2 cells transfected with pcDNA3.1-Hygro vector) into the brains of 6-hydroxydopamine-lesioned PD model rats. From days 10 to 60 after grafting, double immunohistochemistry showed that IL-10 expression was detected in IL-10-c17.2 cells in vivo. Further immunohistochemistry analyses revealed that intracerebral cellular (ED1 and CD8) and humoral (C3 and IgM) immune responses were down-regulated in the rats treated with IL-10-c17.2 cells compared with controls treated with Mock-c17.2 cells. The reduction in ED1 immunostaining in the rats treated with IL-10-c17.2 cells remained significant until day 60 after transplantation. Our results suggest the potential application value of IL-10 in the transplantation treatment of PD.

Neuroinflammation in Parkinson's patients and MPTP-treated mice is not restricted to the nigrostriatal system: microgliosis and differential expression of interleukin-1 receptors in the olfactory bulb

Neuroinflammation may play a role in the pathogenesis of Parkinson's disease (PD). The present study questioned whether this neuroinflammatory response differs between the olfactory bulb, as an early affected region and the nigrostriatal system. Indeed, increased microgliosis was shown in post-mortem olfactory bulb of PD patients. Also in olfactory bulb of MPTP-treated mice, microgliosis and increased expression of IL-1alpha, IL-1beta and IL-1ra mRNA was observed early after treatment. These observations implicate that neuroinflammation is not restricted to the nigrostriatal system. MPTP-induced microgliosis in striatum and olfactory bulb was reduced in IL-1alpha/beta knockout mice, indicating that IL-1 affects microglia activation. Importantly, MPTP induced differential regulation of IL-1 receptors. mRNA levels of IL-1RI and, to a lesser extent, IL-1RII were increased in striatum. Interestingly, in the olfactory bulb only IL-1RII mRNA was enhanced. We suggest that differential regulation of IL-1 signaling can serve as an important mechanism to modulate neuroinflammatory activity after MPTP treatment and possibly during PD.

Influence of age and gender on cytokine expression in a murine model of Parkinson's disease

OBJECTIVE

The neuroinflammatory reaction has been linked with Parkinson's disease. One of the hypotheses to explain the significance of age and gender (male predominance) effects on neurodegeneration in Parkinson's disease may result from a link between these risk factors and the inflammatory processes. Here, we investigated the expression of inflammatory mediators in relation to 1-methyl-4-phenyl-1,2,3,6-tetrahydropiridine (MPTP)-induced neurodegenerative processes in nigrostriatal pathway in young and aged male and female mice.

METHODS AND RESULTS

We simultaneously assessed striatal tyrosine hydroxylase (TH) protein concentrations (Western blotting) and cytokine (TNFalpha, IFNgamma, IL-1beta, IL-6 and TGFbeta(1)) mRNA levels (RT-PCR) in young and aged (2- and 12-month-old) C57BL/6 male and female mice after 6 h, 1, 3, 7, 14, 21 days after MPTP intoxication. Western blotting analysis showed that at the early time points, males showed a greater reduction in striatal TH versus females. Additionally, in contrast to the aged mice, in young males and females the TH concentration gradually increased between the 7th and the 21st day after intoxication. The increases in TNFalpha, IL-1beta and IFNgamma after intoxication were faster in both young and aged males than females. In males (both ages), we observed an increase in TGFbeta(1) at the early time points. In contrast, in females (both ages) TGFbeta(1) was elevated at later time points. MPTP caused an increase in IL-6 in males and females, but this increase was significantly higher in females.

CONCLUSIONS

A gender and age skewing of the cytokine gene expression in the striatum after intoxication may be related to the greater susceptibility in males as well as older animals to the detrimental effects of MPTP.

Peripheral inflammation and neuroprotection: systemic pretreatment with complete Freund's adjuvant reduces 6-hydroxydopamine toxicity in a rodent model of Parkinson's disease

Complete Freund's adjuvant (CFA), a pro-inflammatory agent, was inoculated, subcutaneously, to Sprague-Dawley rats prior to the intrastriatal injection of 6-hydroxydopamine (6-OHDA). Animals were sacrificed 7 and 28 days following 6-OHDA injection; neuronal damage, glial activation and cytokine levels, within the nigrostriatal system, were then investigated. Nigrostriatal degeneration induced by 6-OHDA was accompanied by early microglial and astroglial activation, which preceded the onset of dopaminergic cell loss, in the SNc, without significant changes in cytokine levels. CFA pretreatment markedly reduced the SNc neuronal loss and associated microglial activation, as well as the rotational response to apomorphine. These changes were associated with moderate, transient increases in the nigrostriatal levels of glial-cell-derived neurotrophic factor (GDNF) and pro-inflammatory cytokines, including interleukin (IL)-1alpha, IL-1beta and IL-6. Our results show that prior delivery of a peripheral, pro-inflammatory stimulus induces neuroprotection, in a rodent model of Parkinson's disease, possibly through the modulation of cytokine production at the nigrostriatal level.

Reversible Parkinsonian syndrome associated with anti-neuronal antibodies in acute EBV encephalitis: a case report

We report a case of subacute-onset isolated parkinsonian syndrome in a 16 years old patient. Epstein-Barr infection was diagnosed according to serologic evidences. Parkinson-like syndrome completely recovered after 60 days. Autoantibodies reacting against a 130 Kda antigens expressed in human neuroblastoma cell line were detected. Pathogenesis and differential diagnosis are briefly discussed. EBV testing could be worthwhile in juvenile, acute-onset, parkinsonism.

Gluten sensitivity in Japanese patients with adult-onset cerebellar ataxia

OBJECTIVE

Gluten sensitivity is associated with multiple neurological abnormalities including gluten ataxia, motor neuron disease-like neuropathy, small fiber type neuropathy, cognitive impairment, and even parkinsonism. We investigated whether or not gluten sensitivity is involved in Japanese patients with idiopathic cerebellar ataxia with extracerebellar presentation.

PATIENTS OR MATERIALS

Fourteen patients with idiopathic cerebellar ataxia with extracerebellar presentation (autonomic instability, parkinsonism, or pyramidal dysfunction in varying combinations) were screened for anti-gliadin antibodies (AGA) to analyze for the presence or absence of gluten sensitivity. Patients with typical MR findings of multiple system atrophy of the cerebellar type were excluded. As disease controls without cerebellar ataxia, 9 patients with Parkinson's disease and 18 patients with amyotrophic lateral sclerosis were screened for AGA. Forty-seven normal controls were also screened for AGA.

RESULTS

We found a high prevalence of AGA in 5 (36%) of 14 cerebellar ataxia patients, but in only 1 (4%) of 27 disease controls without cerebellar ataxia (odds ratio, 14.4; 95% CI, 1.41147; p<0.05) and in only 1 (2%) of 47 normal controls (odds ratio, 25.6; 95% CI, 2.66246; p<0.001). Among the cerebellar ataxia patients, atypical features such as sensorimotor neuropathy and/or mild cognitive impairment were more prevalent in the AGA-positive group (60%) than in the AGA-negative group (0%). In one of the ataxic patients with AGA, a gluten-free diet had positive effects on neurological symptoms and nutritional status.

CONCLUSION

Gluten sensitivity is involved in at least some of the unexplained neurological symptoms of Japanese patients with adult-onset, sporadic cerebellar ataxia.

Increased plasma levels of TNF-α but not of IL1-β in MPTP-treated monkeys one year after the MPTP administration

The cause of Parkinson's disease remains unknown although some evidence suggests that an inflammatory reaction, mediated by cytokines such as TNF-alpha and IL-1beta, is related with dopaminergic degeneration in the brain. In the present work we measured the plasma levels of TNF-alpha and IL-1beta in parkinsonian monkeys one year after MPTP administration. TNF-alpha levels were seen to have increased in parkinsonian monkeys reflecting the clinical symptoms observed, while IL-1beta levels remained unchanged. These results suggest that TNF-alpha plays a role in sustaining of dopaminergic degeneration in chronic parkinsonism.

Human umbilical cord matrix stem cells: preliminary characterization and effect of transplantation in a rodent model of Parkinson's disease

The umbilical cord contains an inexhaustible, noncontroversial source of stem cells for therapy. In the U.S., stem cells found in the umbilical cord are routinely placed into bio-hazardous waste after birth. Here, stem cells derived from human umbilical cord Wharton's Jelly, called umbilical cord matrix stem (UCMS) cells, are characterized. UCMS cells have several properties that make them of interest as a source of cells for therapeutic use. For example, they 1) can be isolated in large numbers, 2) are negative for CD34 and CD45, 3) grow robustly and can be frozen/thawed, 4) can be clonally expanded, and 5) can easily be engineered to express exogenous proteins. UCMS cells have genetic and surface markers of mesenchymal stem cells (positive for CD10, CD13, CD29, CD44, and CD90 and negative for CD14, CD33, CD56, CD31, CD34, CD45, and HLA-DR) and appear to be stable in terms of their surface marker expression in early passage (passages 4-8). Unlike traditional mesenchymal stem cells derived from adult bone marrow stromal cells, small populations of UCMS cells express endoglin (SH2, CD105) and CD49e at passage 8. UCMS cells express growth factors and angiogenic factors, suggesting that they may be used to treat neurodegenerative disease. To test the therapeutic value of UCMS cells, undifferentiated human UCMS cells were transplanted into the brains of hemiparkinsonian rats that were not immune-suppressed. UCMS cells ameliorated apomorphine-induced rotations in the pilot test. UCMS cells transplanted into normal rats did not produce brain tumors, rotational behavior, or a frank host immune rejection response. In summary, the umbilical cord matrix appears to be a rich, noncontroversial, and inexhaustible source of primitive mesenchymal stem cells.

Cellular distribution of interleukin-1α-immunoreactivity after MPTP intoxication in mice

In young rodents, peripheral injection of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) results in a dopaminergic nigrostriatal denervation (during the first week after injection), followed by a spontaneous dopaminergic reinnervation. Sprouting from residual neurons has been proposed to account for this event. It has been shown that an inflammatory process takes place during striatal dopaminergic denervation but its consequences remain controversial. Some clues notably indicate that interleukin (IL)-1alpha may participate in MPTP-induced inflammation and promote recovery. We therefore studied the immunohistochemical localization of IL-1alpha expression in the striatum and ventral mesencephalon at different times (1, 3, 6, 16, and 30 days) after MPTP injection in mice. IL-1alpha-immunoreactivity (ir) was observed in striatum, substantia nigra pars compacta, and ventral tegmental area. Apart from a few localization in mesencephalic activated microglia, IL-1alpha was almost exclusively found in activated astrocytes. However, in the striatal parenchyma, another component of IL-1alpha-ir colocalized with tyrosine hydroxylase (TH)-ir, a marker for dopaminergic neurons. Moreover, some parenchymal TH-positive axons were also found to express the growth cone-associated protein (GAP)-43, a marker for axonal growth cones. In the striatum, IL-1alpha-ir was also detected in a non-astrocytic perivascular component, with a distribution similar to GAP-43-ir. IL-1alpha could thus directly or indirectly influence striatal reorganization after MPTP.

In mice, production of plasma IL-1 and IL-6 in response to MPTP is related to behavioral lateralization

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces dopaminergic neuron death in substantia nigra and dopamine loss in striatum, similar to those observed in Parkinson disease. Given MPTP can also induce alterations in brain cytokines and in peripheral immune parameters, we hypothesize that MPTP can induce an elevation of plasma cytokines. We have previously shown that cytokine production depends on behavioral lateralization in certain conditions. Therefore, we further postulate that the MPTP-induced plasma cytokines are related to behavioral lateralization. To answer these questions, C57BL/6J male mice, selected for paw preference, were injected with 25 mg/kg MPTP ip for five consecutive days and were decapitated at day 1, day 3, or day 14 after the last injection. Striatal DA and DOPAC concentration were measured by HPLC and plasma levels of IL-1beta and IL-6 were quantified by ELISA. The results showed that after MPTP treatment, striatal DA content was dramatically decreased, IL-1beta levels increased on day 3, while IL-6 levels increased on day 14. Interestingly, behavioral lateralization influenced DA/DOPAC ratio as well as plasma IL-1beta and IL-6 levels. In left-pawed mice, MPTP induced a higher decrease of DA/DOPAC ratio than in right-pawed mice. The increase of IL-1beta was observed in left-pawed but not in right-pawed mice. The elevation of IL-6 was higher in right-pawed mice than in left-pawed mice. These results have clearly demonstrated our hypotheses, that MPTP can induce increase of plasma IL-1beta and IL-6 levels in mice, and this effect is shaped by behavioral lateralization.

Therapeutic immunization protects dopaminergic neurons in a mouse model of Parkinson's disease

Degeneration of the nigrostriatal dopaminergic pathway, the hallmark of Parkinson's disease, can be recapitulated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. Herein, we demonstrate that adoptive transfer of copolymer-1 immune cells to MPTP recipient mice leads to T cell accumulation within the substantia nigra pars compacta, suppression of microglial activation, and increased local expression of astrocyte-associated glial cell line-derived neurotrophic factor. This immunization strategy resulted in significant protection of nigrostriatal neurons against MPTP-induced neurodegeneration that was abrogated by depletion of donor T cells. Such vaccine treatment strategies may provide benefit for Parkinson's disease.

Time-course of the expression of inflammatory cytokines and matrix metalloproteinases in the striatum and mesencephalon of mice injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a dopaminergic neurotoxin

Injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice results in a retrograde nigrostriatal dopaminergic pathway denervation and subsequent tissue reorganization. Since the role of inflammatory mediators after MPTP remains unclear, proinflammatory cytokine and matrix metalloproteinase (MMP) expression were evaluated by comparative RT-PCR during denervation and tissue reorganization following a single-dose of MPTP (40 mg/kg, s.c.) in young (8-week-old) mice. The time-course of denervation/reorganization was assessed through [(3)H]GBR-12935 binding on dopamine transporter and tyrosine hydroxylase immunohistochemistry. In the striatum, TNF-alpha, IL-1alpha, IL-1beta, IL-6 and MMP-9 mRNA expression peaked on day 1. In the ventral mesencephalon, cytokines (TNF-alpha, IL-1alpha, IL-1beta) and MMP-9 mRNA expression peaked on day 3. During tissue reorganization (day 6 through 16), the only change observed in the striatum consisted of IL-1alpha mRNA and protein overexpression together with MMP-2 downregulation. Whereas the early expression of proinflammatory cytokines and MMP might participate in the retrograde nigrostriatal denervation, the late component of IL-1alpha expression suggests a possible role for this cytokine in the subsequent striatal reorganization.

Role of cytokines in neurological disorders

The balance between cytokines with pro- and anti-inflammatory effects contributes to the course of the Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. TNFalpha seems to be an important factor in the cascade of events leading to demyelination and even axonal damage. During the acute phase, the serum concentrations of TNFalpha and IL-6 are elevated while anti-inflammatory cytokines are up-regulated in the recovery phase. Cytokines also have a key role in the pathogenesis of multiple sclerosis and most data suggest that this effect is mediated by myelin-specific CD4 T lymphocytes secreting Th type 1 cytokines. However, several different immune cells including B lymphocytes, CD8 T lymphocytes and NK T lymphocytes are also involved in the pathogenesis. Both Th1 and Th2 lymphocytes and cytokines probably participate in the development of myasthenia gravis (MG). The IFNalpha production is probably related to the severity of the disease, with clinical improvement associated with decreased production. The serum levels of IL-18 are significantly elevated in MG, with highest concentrations in patients with generalized disease. The immune system may be involved in the pathogenesis of AD by the effect of microglia, which can induce microglial activation with subsequent release of pro-inflammatory cytokines. In parkinsonism, there is evidence of chronic inflammation in the substantia nigra and striatum. Activated microglia, producing proinflammatory cytokines, surround the degenerating dopaminergic neurons and may contribute to the dopaminergic neuron loss. Studies of patients with epilepsy and animals with experimentally induced seizures indicate that cytokines may also influence the electrophysiological properties of neurons.

Dynamics of expression of the mRNA for cytokines and inducible nitric synthase in a murine model of the Parkinson's disease

The inflammatory reaction and oxidative stress has been linked with PD. Proinflammatory cytokines promote neurodegeneration or neuroprotection in different animal models. In addition, these cytokines have been reported to increase iNOS expression. With the RT-PCR method we evaluated mRNA levels for IL 1beta, IL6, TNF, IFNgamma, IL-10 and iNOS in the striatum of C57BL/6 mice after MPTP intoxication. The IL1beta mRNA expression rapidly increased and peaked at 6 h. The first increase of mRNA for TNFalpha and IFNgamma was noticed at 6-24 h and the second at the 7th day after MPTP intoxication. Two peaks of IL10 mRNA were seen, immediately (6 h) and at the 3 day post MPTP injection. The peak of mRNA level for IL6 was observed at the 7th day. Expression of mRNA for iNOS peaked at 24 h, started decreasing on the 3rd day, but was still present till the 14th day. Those findings suggest that cytokine network and iNOS may be involved in the development of immune changes accompanying degeneration of the nigrostriatal system.

Neuroimmunophilin ligands exert neuroregeneration and neuroprotection in midbrain dopaminergic neurons

Immunosuppressant drugs, like FK506, and nonimmunosuppressant compounds like, GPI1046 and L685818, are immunophilin ligands that specifically bind to immunophilins, like FK506 binding protein 12 (FKBP12). Several lines of evidence show that these ligands exert neurotrophic properties in neural injury models and in PC12 cells. However, the mechanism of the neurotrophic function of the immunophilin ligands is poorly known. In the present study, we use MPP+ and 6-OHDA toxicity models to examine both neuroprotective and neuroregenerative effects of immunophilin ligands on primary cultures of midbrain dopaminergic neurons. We find that FK506, GPI1046 and L685818 at concentrations from 0.01 to 1 microM partially, but significantly, protect dopaminergic neurons against both MPP+ and 6-OHDA toxicity. By Western blot analysis, we also find that all three compounds prevent tyrosine hydroxylase (TH) loss induced by MPP+ and 6-OHDA treatments. Morphologic analysis of dopaminergic neurons, by immunocytochemistry, shows that MPP+ and 6-OHDA cause the retraction and loss of neuronal processes, while FK506, GPI1046 and L685818 promote regeneration of these processes as indicated by increases in process number and length. To examine if FKBP12 is required for neurotrophic effects of immunophilin ligands, we cultured dopaminergic neurons from FKBP12 knockout mice and find that FK506 still protects dopaminergic neurons against MPP+ toxicity. These results suggest that FKBP12 is not essential for the neurotrophic properties of immunophilin ligands, and immunophilin ligands are a new class of neuroprotective and neuroregenerative agents that may have therapeutic potential in a variety of neurological disorders.

Lactoferrin is synthesized by activated microglia in the human substantia nigra and its synthesis by the human microglial CHME cell line is upregulated by tumor necrosis factor alpha or 1-methyl-4-phenylpyridinium treatment

The presence of the iron-binding protein lactoferrin (Lf) in some specific areas of the central nervous system and particularly in the normal human substantia nigra, where it is found in dopaminergic (DA) neurons and some glial cells, led us to investigate Lf synthesis in this area. Lf mRNA were identified using in situ hybridization and found in small ameboid cells. These cells were identified using immunocytochemistry as activated microglia since they exhibited macrophage markers such as the CD68 and the CR1 antigens. Double immunofluorescent labeling confirmed that the two Lf immunostained cell populations were activated microglia and DA neurons. Since activated microglia contained both Lf and its messenger, these cells are the Lf producing cells. The presence of Lf in DA neurons in which no Lf messengers were visible, might be due to an endocytosis mechanism, DA neurons probably internalizing Lf produced in microglial cells located in their neighborhood. In neuropathological disorders, such as Alzheimer's and Parkinson's diseases, inflammatory process and oxidative stress are events that contribute to neuronal death. Since Lf concentration increases during these pathologies, we studied the level of Lf expression under these different stresses and showed, using RT-PCR, that the immortalized human embryonic microglial CHME cell line produced Lf transcripts under tumor necrosis factor alpha or 1-methyl-4-phenylpyridinium treatment whereas untreated cells did not. These data confirm that Lf is produced only when microglia are activated.

Minocycline inhibits microglial activation and protects nigral cells after 6-hydroxydopamine injection into mouse striatum

To determine the role of immune/inflammatory factors in dopaminergic cell degeneration in parkinsonian substantia nigra, we assayed tyrosine hydroxylase (TH)-positive immunoreactive neuronal numbers with stereologic techniques and CD11b-positive immunoreactive microglial profiles following 6-hydroxydopamine (6-OHDA) injection into ipsilateral striatum of mice. We further investigated the effect of minocycline on the inhibition of microglial activation and subsequent protection of nigral cells. The relative number of microglial profiles in the substantia nigra (SN) ipsilateral to the injection increased from 31 to 32% 1-3 days after injection, and increased further to 55% by 7 days and 59% by 14 days, compared with the contralateral SN. These changes started prior to the decrease of TH immunoreactivity of 34% on day 7 and of 42% by day 14. In animals treated with minocycline, microglial activation was inhibited by 47%, and TH positive cells were protected by 21% at day 14 after 6-OHDA injection, compared with those parkinsonian animals without minocycline treatment. All these results suggest that microglial activation may be involved in the nigral cell degeneration in 6-OHDA induced parkinsonian mice.

Neural xenotransplantation: pretreatment of porcine embryonic nigral tissue with anti-Gal antibodies and complement is not toxic for the dopaminergic neurons

The immunogenicity of porcine tissue is a major obstacle to its use as donor material in xenotransplantation for neurodegenerative diseases. We are currently evaluating a novel strategy for reducing the immunogenicity, in which the alpha-galactosyl epitope (Galalpha1,3Galbeta1,4GlcNAc-R) is used as a target for antibody- and complement-mediated removal of microglia. In the present study, our aim was to determine whether a pretreatment with antibodies against the alpha-galactosyl epitope (anti-Gal) and complement would lyse or otherwise damage dopaminergic neurons in porcine embryonic ventral mesencephalon (VM), the donor tissue for treatment of Parkinson's disease by xenotransplantation. Cell suspensions prepared from VM tissue from 27-day-old pig embryos were incubated with anti-Gal, purified from normal human serum by affinity chromatography, or medium only (control), and subsequently with rabbit complement. After these pretreatments, the cell suspensions were transplanted into the right striatum of 14 adult rats (two groups of 7 animals). The animals were sacrificed 20 days after transplantation, the brains were processed for histology, and the sections were stained for Nissl substance, porcine neurofilament, tyrosine hydroxylase, and rat CD45 to determine graft volume, presence of porcine neurons, content of dopaminergic cells, and leukocyte infiltration, respectively. The VM tissue pretreated with anti-Gal and complement gave rise to dopaminergic grafts that were indistinguishable from those derived from VM tissue given the control pretreatment. In 5 of the 14 animals, the grafts were infiltrated by host leukocytes, but in two of these recipients, the infiltration was only minimal. We conclude that anti-Gal and complement can be applied to porcine embryonic VM tissue without damaging the dopaminergic neurons and their precursors.

Neuronal intranuclear inclusion disease and juvenile parkinsonism

Juvenile parkinsonism (onset age <20 yrs) is uncommon and few cases with neuropathologic confirmation have been reported. We present the case of a 17-year-old boy who presented with asymmetric arm tremor and bulbar symptoms. His paternal great aunt had parkinsonism with onset at age 22 years. Examination revealed parkinsonism in the absence of additional neurologic signs except for delayed pupillary responses to light. He responded well to levodopa but developed motor fluctuations and disabling dyskinesias after 3 years of treatment. Following attempted withdrawal of levodopa at age 24 years, he developed severe aspiration pneumonia complicated by cardiorepiratory arrests and he died 6 months later. At autopsy, the dominant histologic feature was wide-spread neuronal hyaline intranuclear inclusions. Neuronal depletion was observed in the substantia nigra, locus ceruleus, and, to a lesser extent, in the frontal cortex, and inclusions were particularly prominent in these areas. Inclusions were immunoreactive for ubiquitin and were typical of those seen in neuronal intranuclear inclusion disease (NIID), a rare, multisytem neurodegenerative disease. NIID should be considered in the differential diagnosis of juvenile parkinsonism. A link between NIID and hereditary neurodegenerative disorders characterized by expanded polyglutamine tracts is supported by the similar appearance of intranuclear inclusions in both conditions and by a family history in some cases of NIID.

Increase in level of tumor necrosis factor-alpha in 6-hydroxydopamine-lesioned striatum in rats is suppressed by immunosuppressant FK506

We compared in rats with 6-hydroxydopamine (6-OHDA)-induced hemiparkinsonism the content of tumor necrosis factor (TNF)-alpha in the nigrostriatal dopaminergic region of the control side with that of the 6-OHDA-injected experimental side, and explored the effects of 6-OHDA injection combined with the immunosuppressant FK506 treatment (0.5 or 4 mg/kg per day for 2 weeks). The ratios of the concentration of TNF-alpha in the striatum and substantia nigra on the 6-OHDA injection side to that on the control side in the 6-OHDA hemiparkinsonism rats were significantly higher than those in the control rats without 6-OHDA treatment, whereas those in the rats treated with 6-OHDA and FK506 were not significantly different from those in the control rats. Thus FK506 attenuated increased TNF-alpha level in the nigrostriatal dopaminergic region injured by 6-OHDA treatment.

Intrastriatal ventral mesencephalic xenografts of porcine tissue in rats: immune responses and functional effects

Transplantation of neural tissue from other species has the potential to improve function in patients with neurodegenerative disorders. We investigated the functional effects of embryonic porcine dopaminergic neurons transplanted in a rat model of Parkinson's disease and the immune responses to the grafts in immunosuppressed and nonimmunosuppressed hosts. Twenty-three rats with unilateral 6-hydroxydopamine lesions received dissociated, 27-day-old embryonic porcine ventral mesencephalic tissue in the right striatum. Eighteen rats received cyclosporine (10 mg/kg, IP, daily) during the whole period of 14 weeks, in combination with prednisolone (20 mg/kg, IP, daily) the first 4 days. Five rats served as nonimmunosuppressed controls. All rats were tested for amphetamine-induced rotational behavior at 3-week intervals. Two immunosuppressed rats were excluded due to severe side effects of the treatment. Functional recovery was seen in 9 of 16 immunosuppressed rats at 12 weeks. Six animals remained functionally recovered at 14 weeks and contained an average of 5750+/-1450 (SEM) dopaminergic neurons. Between 9 and 14 weeks, three immunosuppressed rats rejected their grafts, based on rotation scores and immunohistochemical demonstration of cell infiltrates. One additional immunosuppressed rat showed evidence of ongoing rejection at 14 weeks. The striata in animals with ongoing or recent rejection contained large numbers of CD4- and CD8-positive lymphocytes, NK cells, macrophages, and microglia cells, whereas scar tissue was found in rats with grafts rejected at earlier time points (n = 11). Embryonic porcine ventral mesencephalic tissue matures in the adult rat striatum, reinnervates the host brain, and restores behavioral defects. Immunosuppressive treatment was necessary for long-term graft survival and functional recovery, but did not sufficiently protect from rejection mechanisms. Porcine neural tissue is an interesting alternative to embryonic human tissue for intracerebral transplantation in neurodegenerative diseases. However, to achieve stable graft survival in discordant xenogeneic combinations, an appropriate immunosuppressive treatment or donor tissue modifications are needed.