Connectomic Basis for Tremor Control in Stereotactic Radiosurgical Thalamotomy

BACKGROUND AND PURPOSE

Given the increased use of stereotactic radiosurgical thalamotomy and other ablative therapies for tremor, new biomarkers are needed to improve outcomes. Using resting-state fMRI and MR tractography, we hypothesized that a "connectome fingerprint" can predict tremor outcomes and potentially serve as a targeting biomarker for stereotactic radiosurgical thalamotomy.

MATERIALS AND METHODS

We evaluated 27 patients who underwent unilateral stereotactic radiosurgical thalamotomy for essential tremor or tremor-predominant Parkinson disease. Percentage postoperative improvement in the contralateral limb Fahn-Tolosa-Marin Clinical Tremor Rating Scale (TRS) was the primary end point. Connectome-style resting-state fMRI and MR tractography were performed before stereotactic radiosurgery. Using the final lesion volume as a seed, "connectivity fingerprints" representing ideal connectivity maps were generated as whole-brain R-maps using a voxelwise nonparametric Spearman correlation. A leave-one-out cross-validation was performed using the generated R-maps.

RESULTS

The mean improvement in the contralateral tremor score was 55.1% (SD, 38.9%) at a mean follow-up of 10.0 (SD, 5.0) months. Structural connectivity correlated with contralateral TRS improvement (r = 0.52; P  = .006) and explained 27.0% of the variance in outcome. Functional connectivity correlated with contralateral TRS improvement (r = 0.50; P  = .008) and explained 25.0% of the variance in outcome. Nodes most correlated with tremor improvement corresponded to areas of known network dysfunction in tremor, including the cerebello-thalamo-cortical pathway and the primary and extrastriate visual cortices.

CONCLUSIONS

Stereotactic radiosurgical targets with a distinct connectivity profile predict improvement in tremor after treatment. Such connectomic fingerprints show promise for developing patient-specific biomarkers to guide therapy with stereotactic radiosurgical thalamotomy.

Trial of Prasinezumab in Early-Stage Parkinson's Disease

BACKGROUND

Aggregated α-synuclein plays an important role in the pathogenesis of Parkinson's disease. The monoclonal antibody prasinezumab, directed at aggregated α-synuclein, is being studied for its effect on Parkinson's disease.

METHODS

In this phase 2 trial, we randomly assigned participants with early-stage Parkinson's disease in a 1:1:1 ratio to receive intravenous placebo or prasinezumab at a dose of 1500 mg or 4500 mg every 4 weeks for 52 weeks. The primary end point was the change from baseline to week 52 in the sum of scores on parts I, II, and III of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS; range, 0 to 236, with higher scores indicating greater impairment). Secondary end points included the dopamine transporter levels in the putamen of the hemisphere ipsilateral to the clinically more affected side of the body, as measured by ¹²³I-ioflupane single-photon-emission computed tomography (SPECT).

RESULTS

A total of 316 participants were enrolled; 105 were assigned to receive placebo, 105 to receive 1500 mg of prasinezumab, and 106 to receive 4500 mg of prasinezumab. The baseline mean MDS-UPDRS scores were 32.0 in the placebo group, 31.5 in the 1500-mg group, and 30.8 in the 4500-mg group, and mean (±SE) changes from baseline to 52 weeks were 9.4±1.2 in the placebo group, 7.4±1.2 in the 1500-mg group (difference vs. placebo, -2.0; 80% confidence interval [CI], -4.2 to 0.2; P = 0.24), and 8.8±1.2 in the 4500-mg group (difference vs. placebo, -0.6; 80% CI, -2.8 to 1.6; P = 0.72). There was no substantial difference between the active-treatment groups and the placebo group in dopamine transporter levels on SPECT. The results for most clinical secondary end points were similar in the active-treatment groups and the placebo group. Serious adverse events occurred in 6.7% of the participants in the 1500-mg group and in 7.5% of those in the 4500-mg group; infusion reactions occurred in 19.0% and 34.0%, respectively.

CONCLUSIONS

Prasinezumab therapy had no meaningful effect on global or imaging measures of Parkinson's disease progression as compared with placebo and was associated with infusion reactions. (Funded by F. Hoffmann-La Roche and Prothena Biosciences; PASADENA ClinicalTrials.gov number, NCT03100149.).

Peptidylarginine Deiminase Inhibitors Reduce Bacterial Membrane Vesicle Release and Sensitize Bacteria to Antibiotic Treatment

Outer membrane and membrane vesicles (OMV/MV) are released from bacteria and participate in cell communication, biofilm formation and host-pathogen interactions. Peptidylarginine deiminases (PADs) are phylogenetically conserved enzymes that catalyze post-translational deimination/citrullination of proteins, causing structural and functional changes in target proteins. PADs also play major roles in the regulation of eukaryotic extracellular vesicle release. Here we show phylogenetically conserved pathways of PAD-mediated OMV/MV release in bacteria and describe deiminated/citrullinated proteins in E. coli and their derived OMV/MVs. Furthermore, we show that PAD inhibitors can be used to effectively reduce OMV/MV release, both in Gram-negative and Gram-positive bacteria. Importantly, this resulted in enhanced antibiotic sensitivity of both E. coli and S. aureus to a range of antibiotics tested. Our findings reveal novel strategies for applying pharmacological OMV/MV-inhibition to reduce antibiotic resistance.

Peptidylarginine deiminase and deiminated proteins are detected throughout early halibut ontogeny - Complement components C3 and C4 are post-translationally deiminated in halibut (Hippoglossus hippoglossus L.)

Post-translational protein deimination is mediated by peptidylarginine deiminases (PADs), which are calcium dependent enzymes conserved throughout phylogeny with physiological and pathophysiological roles. Protein deimination occurs via the conversion of protein arginine into citrulline, leading to structural and functional changes in target proteins. In a continuous series of early halibut development from 37 to 1050° d, PAD, total deiminated proteins and deiminated histone H3 showed variation in temporal and spatial detection in various organs including yolksac, muscle, skin, liver, brain, eye, spinal cord, chondrocytes, heart, intestines, kidney and pancreas throughout early ontogeny. For the first time in any species, deimination of complement components C3 and C4 is shown in halibut serum, indicating a novel mechanism of complement regulation in immune responses and homeostasis. Proteomic analysis of deiminated target proteins in halibut serum further identified complement components C5, C7, C8 C9 and C1 inhibitor, as well as various other immunogenic, metabolic, cytoskeletal and nuclear proteins. Post-translational deimination may facilitate protein moonlighting, an evolutionary conserved phenomenon, allowing one polypeptide chain to carry out various functions to meet functional requirements for diverse roles in immune defences and tissue remodelling.

Pentraxins CRP-I and CRP-II are post-translationally deiminated and differ in tissue specificity in cod (Gadus morhua L.) ontogeny

Pentraxins are fluid phase pattern recognition molecules that form an important part of the innate immune defence and are conserved between fish and human. In Atlantic cod (Gadus morhua L.), two pentraxin-like proteins have been described, CRP-I and CRP-II. Here we show for the first time that these two CRP forms are post-translationally deiminated (an irreversible conversion of arginine to citrulline) and differ with respect to tissue specific localisation in cod ontogeny from 3 to 84 days post hatching. While both forms are expressed in liver, albeit at temporally differing levels, CRP-I shows a strong association with nervous tissue while CRP-II is strongly associated to mucosal tissues of gut and skin. This indicates differing roles for the two pentraxin types in immune responses and tissue remodelling, also elucidating novel roles for CRP-I in the nervous system. The presence of deimination positive bands for cod CRPs varied somewhat between mucus and serum, possibly facilitating CRP protein moonlighting, allowing the same protein to exhibit a range of biological functions and thus meeting different functional requirements in different tissues. The presented findings may further current understanding of the diverse roles of pentraxins in teleost immune defences and tissue remodelling, as well as in various human pathologies, including autoimmune diseases, amyloidosis and cancer.

Post-translational protein deimination in cod (Gadus morhua L.) ontogeny novel roles in tissue remodelling and mucosal immune defences?

Peptidylarginine deiminases (PADs) are calcium dependent enzymes with physiological and pathophysiological roles conserved throughout phylogeny. PADs promote post-translational deimination of protein arginine to citrulline, altering the structure and function of target proteins. Deiminated proteins were detected in the early developmental stages of cod from 11 days post fertilisation to 70 days post hatching. Deiminated proteins were present in mucosal surfaces and in liver, pancreas, spleen, gut, muscle, brain and eye during early cod larval development. Deiminated protein targets identified in skin mucosa included nuclear histones; cytoskeletal proteins such as tubulin and beta-actin; metabolic and immune related proteins such as galectin, mannan-binding lectin, toll-like receptor, kininogen, Beta2-microglobulin, aldehyde dehydrogenase, bloodthirsty and preproapolipoprotein A-I. Deiminated histone H3, a marker for anti-pathogenic neutrophil extracellular traps, was particularly elevated in mucosal tissues in immunostimulated cod larvae. PAD-mediated protein deimination may facilitate protein moonlighting, allowing the same protein to exhibit a range of biological functions, in tissue remodelling and mucosal immune defences in teleost ontogeny.

Increased citrullination and expression of peptidylarginine deiminases independently of P. gingivalis and A. actinomycetemcomitans in gingival tissue of patients with periodontitis

BACKGROUND

A relationship between rheumatoid arthritis (RA) and periodontitis has been suggested from findings that individuals with RA are prone to have advanced periodontitis and vice versa. In search of possible common pathogenetic features of these two diseases, we investigated the presence of citrullinated proteins and expression of endogenous peptidylarginine deiminases (PAD2 and PAD4), in periodontal tissue of individuals with periodontitis and healthy controls, in relation to the periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), producing leukotoxin as virulence factor. These two oral bacteria have been suggested to be linked to anti-citrullinated protein antibodies in patients with RA.

METHODS

Gingival tissue biopsies were obtained from 15 patients with periodontitis and 15 individuals without periodontal disease. Presence of CD3-positive lymphocytes, citrullinated proteins, PAD2, PAD4, P. gingivalis as well as A. actinomycetemcomitans and Mannheimia haemolytica produced leukotoxins were analysed by immunohistochemistry, followed by triple-blind semi-quantitative analysis. Mann-Whitney and Fisher's exact tests were used to analyse differences between groups. PADI2 and PADI4 mRNA levels were assessed by RT-qPCR and analysed using Wilcoxon signed rank test.

RESULTS

Increased staining of citrullinated proteins was observed in gingival connective tissue from subjects with periodontitis (80%, 12/15) compared to healthy gingival tissue (27%, 4/15), whereas no differences were observed in gingival epithelium. There was also an increased staining of the citrullinating enzymes PAD2 and PAD4 in gingival connective tissue of patients with periodontitis whereas similar levels of PAD2 and PAD4 were observed in the gingival epithelium of the two groups. Similarly, the mRNA levels of PADI2 and PADI4 were also increased in the gingival tissue of patients with periodontitis compared to healthy controls. Furthermore, presence of P. gingivalis and leukotoxins was comparable in both epithelium and connective tissue, from the different investigated individuals with and without periodontitis, and there were no correlations between the presence of periodontal pathogens and the expression of citrullinated proteins or PAD enzymes.

CONCLUSION

Chronic gingival inflammation is associated with increased local citrullination and PAD2 and PAD4 expression in periodontitis. The increased citrullination and PAD2 and PAD4 expression in periodontitis were, however, independent of the presence of periodontal pathogen P. gingivalis and A. actinomycetemcomitans leukotoxin.

Longer Duration of MAO-B Inhibitor Exposure is Associated with Less Clinical Decline in Parkinson's Disease: An Analysis of NET-PD LS1

BACKGROUND

Monoamine oxidase type B (MAO-B) inhibitors exhibit neuroprotective effects in preclinical models of PD but clinical trials have failed to convincingly demonstrate disease modifying benefits in PD patients.

OBJECTIVE

To perform a secondary analysis of NET-PD LS1 to determine if longer duration of MAO-B inhibitor exposure was associated with less clinical decline.

METHODS

The primary outcome measure was the Global Outcome (GO), comprised of 5 measures: change from baseline in the Schwab and England (ADL) scale, the 39-item Parkinson's Disease Questionnaire (PDQ-39), the UPDRS Ambulatory Capacity Scale, the Symbol Digit Modalities Test, and the most recent Modified Rankin Scale. A linear mixed model was used to explore the association between the cumulative duration of MAO-B inhibitor exposure and the GO, adjusting for necessary factors and confounders. Associations between MAO-B inhibitor exposure and each of the five GO components were then studied individually.

RESULTS

1616 participants comprised the analytic sample. Mean observation was 4.1 (SD = 1.4) years, and 784 (48.5%) participants received an MAO-B inhibitor. The regression coefficient of cumulative duration of MAO-B inhibitor exposure (in years) on the GO was - 0.0064 (SE = 0.002, p = 0.001). Significant associations between duration of MAO-B inhibitor exposure and less progression were observed for ADL (p < 0.001), Ambulatory Capacity (p < 0.001), and the Rankin (p = 0.002).

CONCLUSIONS

Our analysis identified a significant association between longer duration of MAO-B inhibitor exposure and less clinical decline. These findings support the possibility that MAO-B inhibitors slow clinical disease progression and suggest that a definitive prospective trial should be considered.

Efficacy of Rotigotine at Different Stages of Parkinson's Disease Symptom Severity and Disability: A Post Hoc Analysis According to Baseline Hoehn and Yahr Stage

Background: The efficacy of rotigotine has been demonstrated in studies of patients with early (i.e. not receiving levodopa) and advanced (i.e. not adequately controlled on levodopa; average 2.5 h/day in ‘off’ state) Parkinson’s disease (PD).

Objective: To further investigate the efficacy of rotigotine transdermal patch across different stages of PD symptom severity and functional disability, according to baseline Hoehn and Yahr (HY) staging.

Methods:Post hoc analysis of six placebo-controlled studies of rotigotine in patients with early PD (SP506, SP512, SP513; rotigotine ≤8 mg/24 h) or advanced-PD (CLEOPATRA-PD, PREFER, SP921; rotigotine ≤16 mg/24 h). Data were pooled and analyzed according to baseline HY stage (1, 2, 3 or 4) for change from baseline to end of maintenance in Unified Parkinson’s Disease Rating Scale (UPDRS) II (activities of daily living), UPDRS III (motor) and UPDRS II+III; statistical tests are exploratory.

Results: Data were available for 2057 patients (HY 1 : 262; HY 2 : 1230; HY 3 : 524; HY 4 : 41). Patients at higher HY stages were older, had a longer time since PD diagnosis and higher baseline UPDRS II+III scores vs patients at lower HY stages. Rotigotine improved UPDRS II+III versus placebo for each individual HY stage (p < 0.05 for each HY stage), with treatment differences increasing with increasing HY stages. Similar results were observed for UPDRS II and UPDRS III.

Conclusions: This post hoc analysis suggests that rotigotine may be efficacious across a broad range of progressive stages of PD symptom severity and functional disability (HY stages 1–4).

Enrichment of malondialdehyde-acetaldehyde antibody in the rheumatoid arthritis joint

Objective

To characterize the expression of malondialdehdye-acetaldehyde (MAA) adducts and anti-MAA antibody in articular tissues and serum of patients with RA.

Methods

Paired sera and SF were examined from 29 RA and 13 OA patients. Anti-MAA antibody, RF, ACPA and total immunoglobulin were quantified. SF-serum measures were compared within and between disease groups. The presence and co-localization of MAA, citrulline and select leukocyte antigens in RA and OA synovial tissues were examined using immunohistochemistry.

Results

Circulating and SF anti-MAA antibody concentrations were higher in RA vs OA by 1.5- to 5-fold. IgG (P < 0.001), IgM (P = 0.006) and IgA (P = 0.036) anti-MAA antibodies were higher in paired RA SF than serum, differences not observed for total immunoglobulin, RF or ACPA. In RA synovial tissues, co-localization of MAA with citrulline and CD19+ or CD27+ B cells was demonstrated and was much higher in magnitude than MAA or citrulline co-localization with T cells, monocytes, macrophages or dendritic cells (P < 0.01).

Conclusion

Anti-MAA antibodies are present in higher concentrations in the RA joint compared with sera, a finding not observed for other disease-related autoantibodies. Co-localization of MAA and citrulline with mature B cells, coupled with the local enrichment of anti-MAA immune responses, implicates MAA-adduct formation in local autoantibody production.

Tumor necrosis factor alpha, citrullination, and peptidylarginine deiminase 4 in lung and joint inflammation

Background

The relationship between lung and joint inflammation in rheumatoid arthritis is poorly understood. Lung inflammation with resultant protein citrullination may trigger anti-citrullinated protein antibodies, inflammation, and arthritis. Alternatively, lung and joint inflammation may be two manifestations of a single underlying pathology. The lung has increased citrullination and TNF-α levels are high in rheumatoid arthritis; however, it is unknown if TNF-α can induce lung protein citrullination. The citrullinating enzyme peptidylarginine deiminase 4 (PAD4) exacerbates TNF-α-induced arthritis, but a role for PAD4 in lung citrullination and TNF-α-induced lung inflammation has not been explored. Our aim was to use TNF-α-overexpressing mice to clarify the intersection of TNF-α, citrullination, PAD4, arthritis, and lung inflammation.

Methods

Lung protein citrullination in wild-type mice, mice that overexpress TNF-α systemically (TNF⁺), TNF⁺PAD4^+/+, and TNF⁺PAD4^-/- mice was quantified by both gel electrophoresis using a citrulline probe and western blot. Hematoxylin and eosin (H&E)-stained lung sections from TNF⁺PAD4^+/+ and TNF⁺PAD4^-/- mice were scored for lung inflammation. H&E-stained ankle joint sections from mice that overexpress TNF-α only in the lungs were assessed for arthritis.

Results

TNF⁺ mice have increased lung protein citrullination. TNF⁺PAD4^-/- mice do not have significantly reduced lung protein citrullination, but do have decreased lung inflammation compared to TNF⁺PAD4^+/+ mice. Mice that overexpress TNF-α only in the lungs do not develop arthritis.

Conclusions

PAD4 exacerbates lung inflammation downstream of TNF-α without having a major role in generalized protein citrullination in inflamed lungs. Also, TNF-α-induced lung inflammation is not sufficient to drive murine arthritis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1068-0) contains supplementary material, which is available to authorized users.

A randomized study of rotigotine dose response on 'off' time in advanced Parkinson's disease

BACKGROUND

Previous phase III studies in patients with advanced Parkinson's disease (PD) not adequately controlled on levodopa demonstrated significant reduction of 'off' time with rotigotine transdermal system up to 16 mg/24 h. However, the minimal effective dose has not been established.

OBJECTIVE

This international, randomized, double-blind, placebo-controlled study (SP921; NCT00522379) investigated rotigotine dose response up to 8 mg/24 h.

METHODS

Patients with advanced idiopathic PD (≥2.5 h of daily 'off' time on stable doses of levodopa) were randomized 1:1:1:1:1 to receive rotigotine 2, 4, 6, or 8 mg/24 h or placebo, titrated over 4 weeks and maintained for 12 weeks. The primary efficacy variable was change from baseline to end of maintenance in absolute time spent 'off'.

RESULTS

409/514 (80%) randomized patients completed maintenance. Mean (±SD) baseline daily 'off' times (h/day) were placebo: 6.4 (±2.5), rotigotine 2-8 mg/24 h: 6.4 (±2.6). Rotigotine 8 mg/24 h was the minimal dose to significantly reduce 'off' time versus placebo. LS mean (±SE) absolute change in daily 'off' time (h/day) from baseline was -2.4 (±0.28) with rotigotine 8 mg/24 h, and -1.5 (±0.26) with placebo; absolute change in 'off' time in the 8 mg/24 h group compared with placebo was -0.85 h/day (95% CI -1.59, -0.11; p = 0.024). There was an apparent dose-dependent trend. Adverse events (AEs) reported at a higher incidence in the rotigotine 8 mg/24 h group versus placebo included application site reactions, nausea, dry mouth, and dyskinesia; there was no worsening of insomnia, somnolence, orthostatic hypotension, confusional state or hallucinations, even in patients ≥75 years of age.

CONCLUSIONS

The minimal statistically significant effective dose of rotigotine to reduce absolute 'off' time was 8 mg/24 h. The AE profile was similar to previous studies.

A novel role for peptidylarginine deiminases in microvesicle release reveals therapeutic potential of PAD inhibition in sensitizing prostate cancer cells to chemotherapy

INTRODUCTION

Protein deimination, defined as the post-translational conversion of protein-bound arginine to citrulline, is carried out by a family of 5 calcium-dependent enzymes, the peptidylarginine deiminases (PADs) and has been linked to various cancers. Cellular microvesicle (MV) release, which is involved in cancer progression, and deimination have not been associated before. We hypothesize that elevated PAD expression, observed in cancers, causes increased MV release in cancer cells and contributes to cancer progression.

BACKGROUND

We have previously reported that inhibition of MV release sensitizes cancer cells to chemotherapeutic drugs. PAD2 and PAD4, the isozymes expressed in patients with malignant tumours, can be inhibited with the pan-PAD-inhibitor chloramidine (Cl-am). We sought to investigate whether Cl-am can inhibit MV release and whether this pathway could be utilized to further increase the sensitivity of cancer cells to drug-directed treatment.

METHODS

Prostate cancer cells (PC3) were induced to release high levels of MVs upon BzATP stimulation of P2X7 receptors. Western blotting with the pan-protein deimination antibody F95 was used to detect a range of deiminated proteins in cells stimulated to microvesiculate. Changes in deiminated proteins during microvesiculation were revealed by immunoprecipitation and immunoblotting, and mass spectrometry identified deiminated target proteins with putative roles in microvesiculation.

CONCLUSION

We report for the first time a novel function of PADs in the biogenesis of MVs in cancer cells. Our results reveal that during the stimulation of prostate cancer cells (PC3) to microvesiculate, PAD2 and PAD4 expression levels and the deimination of cytoskeletal actin are increased. Pharmacological inhibition of PAD enzyme activity using Cl-am significantly reduced MV release and abrogated the deimination of cytoskeletal actin. We demonstrated that combined Cl-am and methotrexate (MTX) treatment of prostate cancer cells increased the cytotoxic effect of MTX synergistically. Refined PAD inhibitors may form part of a novel combination therapy in cancer treatment.

Malondialdehyde-acetaldehyde adducts and anti-malondialdehyde-acetaldehyde antibodies in rheumatoid arthritis

OBJECTIVE

Malondialdehyde-acetaldehyde (MAA) adducts are a product of oxidative stress associated with tolerance loss in several disease states. This study was undertaken to investigate the presence of MAA adducts and circulating anti-MAA antibodies in patients with rheumatoid arthritis (RA).

METHODS

Synovial tissue from patients with RA and patients with osteoarthritis (OA) were examined for the presence of MAA-modified and citrullinated proteins. Anti-MAA antibody isotypes were measured in RA patients (n = 1,720) and healthy controls (n = 80) by enzyme-linked immunosorbent assay. Antigen-specific anti-citrullinated protein antibodies (ACPAs) were measured in RA patients using a multiplex antigen array. Anti-MAA isotype concentrations were compared in a subset of RA patients (n = 80) and matched healthy controls (n = 80). Associations of anti-MAA antibody isotypes with disease characteristics, including ACPA positivity, were examined in all RA patients.

RESULTS

Expression of MAA adducts was increased in RA synovial tissue compared to OA synovial tissue, and colocalization with citrullinated proteins was found. Increased levels of anti-MAA antibody isotypes were observed in RA patients compared to controls (P < 0.001). Among RA patients, anti-MAA antibody isotypes were associated with seropositivity for ACPAs and rheumatoid factor (P < 0.001) in addition to select measures of disease activity. Higher anti-MAA antibody concentrations were associated with a greater number of positive antigen-specific ACPA analytes (expressed at high titer) (P < 0.001) and a higher ACPA score (P < 0.001), independent of other covariates.

CONCLUSION

MAA adduct formation is increased in RA and appears to result in robust antibody responses that are strongly associated with ACPAs. These results support speculation that MAA formation may be a cofactor that drives tolerance loss, resulting in the autoimmune responses characteristic of RA.

Parkinson's disease severity and use of dopaminergic medications

BACKGROUND

The effects of dopaminergic therapy in parkinson's disease (PD) can vary depending on the class of medication selected.

OBJECTIVE

The aim of this post hoc study was to determine if the class of dopaminergic therapy correlated with disease severity in persons with early, treated PD.

METHODS

A non-parametric global statistical test (GST) was used to assess the status of participants treated with dopamine agonist (DA) monotherapy, levodopa (LD) monotherapy or combined LD and DA therapy on multiple PD outcomes encompassing motor, cognitive, psychiatric and autonomic function, as well as disability and quality of life.

RESULTS

The outcomes measured at the beginning of the study showed lower disease burden for participants on initial DA monotherapy compared to those taking combined LD and DA therapy after controlling for age, education, taking cog-meds and amantadine.

CONCLUSION

This observation suggests that clinicians treating early PD patients favor combined LD and DA therapy in patients with more disabling features over DA monotherapy. As such, studies of PD progression in treated PD patients may be affected by the class of symptomatic dopaminergic therapy.

Latent information in fluency lists predicts functional decline in persons at risk for Alzheimer disease

OBJECTIVE

We constructed random forest classifiers employing either the traditional method of scoring semantic fluency word lists or new methods. These classifiers were then compared in terms of their ability to diagnose Alzheimer disease (AD) or to prognosticate among individuals along the continuum from cognitively normal (CN) through mild cognitive impairment (MCI) to AD.

METHOD

Semantic fluency lists from 44 cognitively normal elderly individuals, 80 MCI patients, and 41 AD patients were transcribed into electronic text files and scored by four methods: traditional raw scores, clustering and switching scores, "generalized" versions of clustering and switching, and a method based on independent components analysis (ICA). Random forest classifiers based on raw scores were compared to "augmented" classifiers that incorporated newer scoring methods. Outcome variables included AD diagnosis at baseline, MCI conversion, increase in Clinical Dementia Rating-Sum of Boxes (CDR-SOB) score, or decrease in Financial Capacity Instrument (FCI) score. Receiver operating characteristic (ROC) curves were constructed for each classifier and the area under the curve (AUC) was calculated. We compared AUC between raw and augmented classifiers using Delong's test and assessed validity and reliability of the augmented classifier.

RESULTS

Augmented classifiers outperformed classifiers based on raw scores for the outcome measures AD diagnosis (AUC .97 vs. .95), MCI conversion (AUC .91 vs. .77), CDR-SOB increase (AUC .90 vs. .79), and FCI decrease (AUC .89 vs. .72). Measures of validity and stability over time support the use of the method.

CONCLUSION

Latent information in semantic fluency word lists is useful for predicting cognitive and functional decline among elderly individuals at increased risk for developing AD. Modern machine learning methods may incorporate latent information to enhance the diagnostic value of semantic fluency raw scores. These methods could yield information valuable for patient care and clinical trial design with a relatively small investment of time and money.

Peptidylarginine deiminases: novel drug targets for prevention of neuronal damage following hypoxic ischemic insult (HI) in neonates

Neonatal hypoxic ischaemic (HI) injury frequently causes neural impairment in surviving infants. Our knowledge of the underlying molecular mechanisms is still limited. Protein deimination is a post-translational modification caused by Ca⁺²-regulated peptidylarginine deiminases (PADs), a group of five isozymes that display tissue-specific expression and different preference for target proteins. Protein deimination results in altered protein conformation and function of target proteins, and is associated with neurodegenerative diseases, gene regulation and autoimmunity. In this study, we used the neonatal HI and HI/infection [lipopolysaccharide (LPS) stimulation] murine models to investigate changes in protein deimination. Brains showed increases in deiminated proteins, cell death, activated microglia and neuronal loss in affected brain areas at 48 h after hypoxic ischaemic insult. Upon treatment with the pan-PAD inhibitor Cl-amidine, a significant reduction was seen in microglial activation, cell death and infarct size compared with control saline or LPS-treated animals. Deimination of histone 3, a target protein of the PAD4 isozyme, was increased in hippocampus and cortex specifically upon LPS stimulation and markedly reduced following Cl-amidine treatment. Here, we demonstrate a novel role for PAD enzymes in neural impairment in neonatal HI Encephalopathy, highlighting their role as promising new candidates for drug-directed intervention in neurotrauma.

Hypoxic Ischaemic Insult (HI) results in activation of peptidylarginine deiminases (PADs) because of calcium dysregulation. Target proteins undergo irreversible changes of protein bound arginine to citrulline, resulting in protein misfolding. Infection in synergy with HI causes up-regulation of TNFα, nuclear translocation of PAD4 and change in gene regulation as a result of histone deimination. Pharmacological PAD inhibition significantly reduced HI brain damage.

Impaired financial abilities in Parkinson's disease patients with mild cognitive impairment and dementia

PURPOSE

Financial capacity (FC) is an instrumental activity of daily living (IADL) critical to independent functioning and sensitive to cognitive impairment in dementia. Little is known about FC in cognitively impaired patients with Parkinson's disease (PD). The present study investigated FC in PD patients with prodromal and clinical dementia.

METHODS

Participants were 20 older controls and 35 PD patients who met consensus criteria for either mild cognitive impairment (PD-MCI, n = 18) or PD dementia (PDD, n = 17). FC was assessed using a standardized performance based measure consisting of 9 domain and two global scores (Financial Capacity Instrument; FCI) (1). FCI domain and global performance scores were compared across groups. Capacity impairment ratings (no impairment, mild/moderate impairment, severe impairment) were calculated for each PD patient's domain and global scores.

RESULTS

Relative to controls, PD-MCI patients were impaired on both FCI global scores and domains of basic monetary skills, financial concepts, and investment decision-making. Relative to both controls and PD-MCI patients, PDD patients were impaired on virtually all FCI variables. With respect to impairment ratings, greater than 50% of PD-MCI patients and greater than 90% of PDD patients were classified as either mild/moderate or severely impaired on the two FCI global scores.

CONCLUSIONS

Impairment of financial capacity is already present in PD-MCI and is advanced in PDD. Complex cognitively-mediated IADLs such as financial capacity appear to be impaired early in the course of PD dementia.

Nonmotor symptoms in Parkinson's disease: expanding the view of Parkinson's disease beyond a pure motor, pure dopaminergic problem

Nonmotor symptoms (NMS) of Parkinson's disease (PD) are critical to identify and treat because of their impact on quality of life. Despite growing evidence of the importance of NMS on patients' quality of life, gaps remain in their recognition and treatment. The result is a need for increased information and understanding of specific NMS and the clinical approaches for their assessment and management in the context of PD as a whole. This article discusses the NMS of PD, their relationship to the pathologic basis of PD, and how NMS can be best managed.

Randomized clinical trial of fipamezole for dyskinesia in Parkinson disease (FJORD study)

OBJECTIVE

Fipamezole, a selective α2-adrenergic receptor antagonist, reduced levodopa-induced dyskinesias (LID) in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned monkeys. In 10 dyskinetic subjects with Parkinson disease (PD), a proof-of-concept study showed beneficial effects at single doses of 60 and 90 mg. The primary study objective was to assess suppression of LID by fipamezole at day 28, as measured by the levodopa-induced dyskinesia scale (LIDS), a modification of the abnormal involuntary movement scale.

METHODS

This was a double-blind, randomized, placebo-controlled, dose-escalating 28-day study in levodopa-treated patients with PD experiencing LID, conducted at 25 centers in the United States (115 subjects) and 7 centers in India (64 subjects). Dyskinesias were evaluated 3 times after subjects became "on" from levodopa. Outcome assessment was performed with analysis of variance, which evaluated fipamezole dose-effects in a hierarchical stepwise manner and the Jonckheere test for dose responsiveness.

RESULTS

The total study population showed no statistically significant primary endpoint difference. However, because of inhomogeneity recognized between U.S. and Indian study populations, a prespecified subgroup analysis of U.S. subjects was conducted, showing fipamezole at 90 mg reduced LID (mean, 95% CI, LID rating improvement vs placebo -1.9 [0.0 to -3.8; p = 0.047]). Dose responsiveness was demonstrated (p = 0.014 for placebo, 30, 60, and 90 mg fipamezole). Fipamezole induced mild, transient blood pressure elevation and was associated with an acceptable profile of adverse effects.

CONCLUSIONS

The evidence of efficacy in the US subgroup suggested that fipamezole at 90 mg TID may be useful to treat LID in PD without exacerbating parkinsonism.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that fipamezole is well-tolerated and, in the US subpopulation, lessens LID at 90 mg TID.

The periodontium of periodontitis patients contains citrullinated proteins which may play a role in ACPA (anti-citrullinated protein antibody) formation

AIM

To determine the presence and location (stroma versus epithelium) of citrullinated proteins in periodontitis tissue as compared to non-periodontitis tissue and synovial tissue of RA patients.

MATERIALS & METHODS

Periodontitis, healthy periodontal and RA-affected synovial tissue samples were collected in addition to buccal swabs. These samples were stained for the presence of citrullinated proteins using polyclonal (Ab5612) and monoclonal (F95) antibodies. Furthermore, Western blotting with F95 was performed on lysates prepared from periodontal and synovial tissues.

RESULTS

In periodontitis stroma, increased citrullinated protein presence (80%) was observed compared with control stroma (33%), the latter was associated with inflammation of non-periodontitis origin. Periodontal epithelium always stained positive for Ab5612. Noteworthy, only periodontitis-affected epithelium stained positive for F95. All buccal mucosal swabs and 3 of 4 synovial tissue samples stained positive for both Ab5612 and F95. Western blotting with F95 showed presence of similar citrullinated proteins in both periodontitis and RA-affected synovial tissue.

CONCLUSION

Within the periodontal stroma, citrullination is an inflammation-depended process. In periodontal epithelium, citrullination is a physiological process. Additional citrullinated proteins are formed in periodontitis, apparently similar to those formed in RA-affected synovial tissue. Periodontitis induced citrullination may play a role in the aetiology of rheumatoid arthritis.

Local administration of glucocorticoids decreases synovial citrullination in rheumatoid arthritis

Introduction

Protein citrullination is present in the rheumatoid synovium, presumably contributing to the perpetuation of chronic inflammation, in the presence of specific autoimmunity. As a result, the present study examined the possibility that effective antirheumatic treatment will decrease the level of synovial citrullination.

Methods

Synovial biopsies were obtained from 11 rheumatoid arthritis (RA) patients before and after 8 weeks of treatment with 20 mg methotrexate weekly, 15 RA patients before and 2 weeks after an intraarticular glucocorticoid injection, and eight healthy volunteers. Synovial inflammation was assessed with double-blind semiquantitative analysis of lining thickness, cell infiltration, and vascularity by using a 4-point scale. Expression of citrullinated proteins (CPs) with the monoclonal antibody F95 and peptidylarginine deiminase (PAD) 2 and 4 was assessed immunohistochemically with double-blind semiquantitative analysis. In vitro synovial fluid (SF), peripheral blood (PB), mononuclear cells (MCs), and synovial explants obtained from RA patients were incubated with dexamethasone and analyzed with immunohistochemistry for expression of CP as well as PAD2 and PAD4 enzymes.

Results

The presence of synovial CP was almost exclusive in RA compared with healthy synovium and correlated with the degree of local inflammation. Treatment with glucocorticoids but not methotrexate alters expression of synovial CP and PAD enzymes, in parallel with a decrease of synovial inflammation. Ex vivo and in vitro studies suggest also a direct effect of glucocorticoids on citrullination, as demonstrated by the decrease in the level of citrullination and PAD expression after incubation of SFMC and synovial explants with dexamethasone.

Conclusion

Synovial citrullination and PAD expression are dependent on local inflammation and targeted by glucocorticoids.

Protein deiminases: new players in the developmentally regulated loss of neural regenerative ability

Spinal cord regenerative ability is lost with development, but the mechanisms underlying this loss are still poorly understood. In chick embryos, effective regeneration does not occur after E13, when spinal cord injury induces extensive apoptotic response and tissue damage. As initial experiments showed that treatment with a calcium chelator after spinal cord injury reduced apoptosis and cavitation, we hypothesized that developmentally regulated mediators of calcium-dependent processes in secondary injury response may contribute to loss of regenerative ability. To this purpose we screened for such changes in chick spinal cords at stages of development permissive (E11) and non-permissive (E15) for regeneration. Among the developmentally regulated calcium-dependent proteins identified was PAD3, a member of the peptidylarginine deiminase (PAD) enzyme family that converts protein arginine residues to citrulline, a process known as deimination or citrullination. This post-translational modification has not been previously associated with response to injury. Following injury, PAD3 up-regulation was greater in spinal cords injured at E15 than at E11. Consistent with these differences in gene expression, deimination was more extensive at the non-regenerating stage, E15, both in the gray and white matter. As deimination paralleled the extent of apoptosis, we investigated the effect of blocking PAD activity on cell death and deiminated-histone 3, one of the PAD targets we identified by mass-spectrometry analysis of spinal cord deiminated proteins. Treatment with the PAD inhibitor, Cl-amidine, reduced the abundance of deiminated-histone 3, consistent with inhibition of PAD activity, and significantly reduced apoptosis and tissue loss following injury at E15. Altogether, our findings identify PADs and deimination as developmentally regulated modulators of secondary injury response, and suggest that PADs might be valuable therapeutic targets for spinal cord injury.

MS analysis of rheumatoid arthritic synovial tissue identifies specific citrullination sites on fibrinogen

PURPOSE

Citrullination is a post-translational modification of arginine residues to citrulline catalyzed by peptidyl arginine deiminases. Induced expression of citrullinated proteins are frequently detected in various inflammatory states including arthritis; however, direct detection of citrullination in arthritic samples has not been successfully performed in the past.

EXPERIMENTAL DESIGN

Citrullination of human fibrinogen, a candidate autoantigen in arthritis, was studied. Accurate identification of citrullinated fibrinogen peptides from rheumatoid arthritis synovial tissue specimens was performed using accurate mass and retention time analysis.

RESULTS

A peptide with the sequence ESSSHHPGIAEFPSRGK corresponding to amino acids 559-575 of fibrinogen α-chain was identified to be citrullinated with an occupancy rate between 1.4 and 2.5%. Citrullination of the peptide KREEAPSLRPAPPPISGGGYRARPAK corresponding to amino acids 52-77 of the fibrinogen β-chain was identified with an occupancy rate of 1.2%.

CONCLUSIONS AND CLINICAL RELEVANCE

We report a proof of principle study for the identification of citrullinated proteins and within them, identification of citrullination sites and quantification of their occupancies in synovial tissue from rheumatoid arthritis patients using high-resolution MS. Detailed studies on which molecules are citrullinated in arthritis can provide information about their role in immune regulation and serve as novel biomarkers and potentially even as therapeutic targets.

Relief of acquired stuttering associated with Parkinson's disease by unilateral left subthalamic brain stimulation

PURPOSE

In this article, the authors report a case of acquired stuttering associated with Parkinson's disease (PD) that was responsive to unilateral subthalamic nucleus deep-brain stimulation (STN DBS) in the language-dominant hemisphere.

METHOD

A single-subject, masked, multiple baseline design was used to evaluate the effects of unilateral left STN DBS on stuttering associated with PD. The patient underwent 3 formal speech assessments of spontaneous speech and the reading of passages with DBS off and on. Speech samples were videotaped and placed in random order, and 2 independent speech-language pathologists calculated the percentage of stuttered syllables and classified individual stuttering events.

RESULTS

Stuttering improved significantly in the DBS-on condition. In total, 10% of syllables were affected by stuttering events with DBS off, and less than 1% of syllables were affected by stuttering events with DBS on (n = 2,281 syllables, p < .00001, in a chi(2) test). The effect of unilateral STN DBS on stuttering was relatively independent of whether the patient was on or off dopaminergic medications.

CONCLUSION

This article emphasizes the important role of the subthalamic region in the motor control of speech and language.

The contribution of executive control on verbal-learning impairment in patients with Parkinson's disease with dementia and Alzheimer's disease

Deficits in learning, memory, and executive functions are common cognitive sequelae of Parkinson's disease with dementia (PDD) and Alzheimer's disease (AD); however, the pattern of deficits within these populations is distinct. Hierarchical regression was used to investigate the contribution of two measures with executive function properties (Verbal Fluency and CLOX) on list-learning performance (CVLT-II total words learned) in a sample of 25 PDD patients and 25 matched AD patients. Executive measures were predictive of list learning in the PDD group after the contribution of overall cognition and contextual verbal learning was accounted for, whereas in the AD group the addition of executive measures did not add to prediction of variance in CVLT-II learning. These findings suggest that deficits in executive functions play a vital role in learning impairments in patients with PDD; however, for AD patients, learning difficulties appear relatively independent of executive dysfunction.

Clinical interview assessment of financial capacity in older adults with mild cognitive impairment and Alzheimer's disease

OBJECTIVES

To investigate financial capacity in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) using a clinician interview approach.

DESIGN

Cross-sectional.

SETTING

Tertiary care medical center.

PARTICIPANTS

Healthy older adults (n=75) and patients with amnestic MCI (n=58), mild AD (n=97), and moderate AD (n=31).

MEASUREMENTS

The investigators and five study physicians developed a conceptually based, semistructured clinical interview for evaluating seven core financial domains and overall financial capacity (Semi-Structured Clinical Interview for Financial Capacity; SCIFC). For each participant, a physician made capacity judgments (capable, marginally capable, or incapable) for each financial domain and for overall capacity.

RESULTS

Study physicians made more than 11,000 capacity judgments across the study sample (N=261). Very good interrater agreement was obtained for the SCIFC judgments. Increasing proportions of marginal and incapable judgment ratings were associated with increasing disease severity across the four study groups. For overall financial capacity, 95% of physician judgments for older controls were rated as capable, compared with 82% for patients with MCI, 26% for patients with mild AD, and 4% for patients with moderate AD.

CONCLUSION

Physicians and other clinicians can reliably evaluate financial capacity in cognitively impaired older adults using a relatively brief, semistructured clinical interview. Patients with MCI have mild impairment in financial capacity, those with mild AD have emerging global impairment, and those with moderate AD have advanced global impairment. Patients with MCI and their families should proactively engage in financial and legal planning, given these patients' risk of developing AD and accelerated loss of financial abilities.

Medical decision-making capacity in cognitively impaired Parkinson's disease patients without dementia

Little is currently known about the higher order functional skills of patients with Parkinson disease and cognitive impairment. Medical decision-making capacity (MDC) was assessed in patients with Parkinson's disease (PD) with cognitive impairment and dementia. Participants were 16 patients with PD and cognitive impairment without dementia (PD-CIND), 16 patients with PD dementia (PDD), and 22 healthy older adults. All participants were administered the Capacity to Consent to Treatment Instrument (CCTI), a standardized capacity instrument assessing MDC under five different consent standards. Parametric and nonparametric statistical analyses were utilized to examine capacity performance on the consent standards. In addition, capacity outcomes (capable, marginally capable, or incapable outcomes) on the standards were identified for the two patient groups. Relative to controls, PD-CIND patients demonstrated significant impairment on the understanding treatment consent standard, clinically the most stringent CCTI standard. Relative to controls and PD-CIND patients, PDD patients were impaired on the three clinical standards of understanding, reasoning, and appreciation. The findings suggest that impairment in decisional capacity is already present in cognitively impaired patients with PD without dementia and increases as these patients develop dementia. Clinicians and researchers should carefully assess decisional capacity in all patients with PD with cognitive impairment.

Striatal histone modifications in models of levodopa-induced dyskinesia

Despite recent advances in the treatment of Parkinson disease (PD), levodopa remains the most effective and widely used therapy. A major limitation to the use of levodopa is the development of abnormal involuntary movements, termed levodopa-induced dyskinesia (LDID), following chronic levodopa treatment. Since recent studies have suggested that modifications of chromatin structure may be responsible for many long-lasting changes in brain function, we have examined post-translational modifications of striatal histones in two models of LDID: an acute murine model and a chronic macaque monkey model, both exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In the primate model, which closely resembles human LDID, we observed that chronic levodopa and the appearance of LDID was associated with marked deacetylation of histone H4, hyperacetylation and dephosphorylation of histone H3, and enhancement of the phosphorylation of extracellular signal-regulated kinase (ERK). In the murine model of acutely rather than chronically induced LDID, dopamine depletion and levodopa treatment also induced deacetylation of histone H4 and phosphorylation of ERK, but histone H3 exhibited decreased trimethylation and reduced rather than enhanced acetylation. These data demonstrate striking changes in striatal histones associated with the induction of LDID in both animal models. The pattern of changes observed, as well as the behavioral features, differed in the two models. However, both models exhibit marked deacetylation of histone H4, suggesting that inhibitors of H4 deacetylation may be useful in preventing or reversing LDID.

Smoking increases peptidylarginine deiminase 2 enzyme expression in human lungs and increases citrullination in BAL cells

OBJECTIVES

A gene-environment interaction between HLA-DR shared epitope genes and smoking in anti-cyclic citrullinated peptide antibody-positive rheumatoid arthritis (RA) has been reported. Identification of citrullinated proteins in bronchoalveolar lavage (BAL) cells from smokers has led to the suggestion that citrullination induced by smoking might be the first step in the pathogenic chain of RA.

OBJECTIVE

To confirm and extend these findings.

METHODS

Immunohistochemistry was performed on BAL cells and bronchial mucosal biopsy sections obtained through bronchoscopy from 14 healthy smokers and 16 healthy non-smokers. Two antibodies recognising citrullinated proteins, two antibodies recognising peptidylarginine deiminase (PAD)2 enzyme and one recognising PAD4 enzyme were used.

RESULTS

Citrullinated proteins are upregulated in BAL cells of healthy smokers compared with healthy non-smokers. This was associated with higher expression of the PAD2 enzyme. The same level of citrullinated proteins was present in bronchial mucosal biopsy specimens of healthy smokers and non-smokers, despite higher expression of PAD2 in smokers.

CONCLUSION

This study provides evidence that smoking enhances PAD2 expression in the bronchial mucosal and alveolar compartment, with consequent generation of citrullinated proteins in the latter. Smoking is an environmental factor that may lead to citrulline autoimmunity in genetically susceptible subjects.

Levodopa-induced hyperactivity in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

The present study examines the motor responses of 10- to 12-month-old, male C57 mice that were either given intraperitoneal (IP) injections of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 30 mg/kg per day) or vehicle for 10 consecutive days, followed by IP injections of levodopa (200 mg/kg) plus carbidopa (25 mg/kg). Five days of MPTP exposure resulted in the Straub tail phenomenon and pronounced hypokinesia. However, during the next 5 days, motor activity returned to baseline, even with continued MPTP treatment. After 10 to 14 days of rest, all mice were then treated with levodopa/carbidopa twice daily for multiple, consecutive days. However, only the previously MPTP-treated animals became hyperkinetic, as compared to levodopa-treated control animals that were not previously exposed to MPTP. Abnormal activity included scratching, running, gnawing, and jumping movements. Hyperactivity lasted for approximately 2 hours after each levodopa injection and then returned to baseline, but the amount of hyperkinesia increased with additional days of levodopa treatment, even though the daily levodopa dose was not changed. These results demonstrate that levodopa can cause reproducible hyperactivity in mice that were previously exposed to MPTP.

Synovial intracellular citrullinated proteins colocalizing with peptidyl arginine deiminase as pathophysiologically relevant antigenic determinants of rheumatoid arthritis-specific humoral autoimmunity

OBJECTIVE

To address the ongoing debate concerning the specificity of synovial citrullinated proteins for rheumatoid arthritis (RA) and to analyze their pathophysiologic relevance to the induction or perpetuation of the RA-specific anti-citrullinated protein antibodies (ACPAs).

METHODS

Synovium of 19 RA patients and 19 non-RA controls was immunostained for the presence of citrullinated proteins with a mouse monoclonal antibody (F95), for the citrullinating enzyme peptidyl arginine deiminase type 2 (PAD-2), and for the free citrulline-producing enzyme inducible nitric oxide synthase (iNOS). Extending the RA cohort to 61 patients, the findings of anticitrulline staining in synovium were related to serum and synovial fluid ACPA levels, as measured by enzyme-linked immunosorbent assay.

RESULTS

F95 staining indicated the presence of synovial intracellular citrullinated proteins in 53% of RA samples versus 5% of control samples, whereas extracellular staining was not RA specific. Immunoblotting and inhibition experiments confirmed that the antibody recognized citrullinated proteins but not free citrulline. Accordingly, iNOS was equally found in RA and control synovium and in intracellular citrullinated protein-positive and intracellular citrullinated protein-negative samples. In contrast, intracellular citrullinated proteins colocalized with PAD-2, which was found in 59% of RA samples versus 17% of control samples. Independent of local disease activity, the presence of the RA-specific synovial intracellular citrullinated proteins was associated with significantly higher systemic and local ACPA levels and with local ACPA production in the joint.

CONCLUSION

These data confirm the presence of RA-specific intracellular citrullinated proteins in synovium. The link with PAD-2 and local and systemic ACPA levels emphasizes their pathophysiologic relevance for RA-specific humoral autoimmunity.

Atypical Hallervorden-Spatz disease with preserved cognition and obtrusive obsessions and compulsions

We describe the case of an adult female with Hallervorden-Spatz disease (HSD), "eye-of-the-tiger" sign on cranial magnetic resonance imaging scan, and two mutations in the pantothenate kinase 2 (PANK2) gene. Symptomatic presentation included stuttering dysarthria, dystonic posturing, increased limb and axial muscle tone, choreoathetosis, stereotyped motor behaviors, and obsessive-compulsive symptomatology since adolescence. Extensive neuropsychological testing at 40 and 44 years of age revealed a relatively normal IQ and stable cognitive pattern overall. This case demonstrates that HSD patients who survive into middle age should not be assumed to have a progressive dementia. In such cases, atypical behavioral problems such as persistent obsessions and compulsions may be present instead.

Expression of citrullinated proteins in murine experimental autoimmune encephalomyelitis

In this study, we demonstrate for the first time the immunohistochemical expression of citrullinated proteins in the central nervous system (CNS) of mice with myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE). By using an established monoclonal antibody (F95) against natural and synthetic citrullinated proteins (Nicholas and Whitaker [2002] Glia 37:328-336), numerous, small, previously unrecognized "patches" of citrullinated proteins were discovered throughout EAE brains, whereas EAE spinal cords showed similar but much larger lesions. On dual color immunofluorescence, these lesions were found to contain citrullinated myelin basic protein (MBP) and were surrounded by astrocytes immunoreactive for both glial fibrillary acidic protein (GFAP) and F95. These lesions became evident about the time when EAE mice became symptomatic and increased in size and number with increasing disease severity. In some sections of spinal cord but not brains of severely debilitated EAE mice, a widespread gliotic response was seen, with astrocytes containing citrullinated GFAP spread throughout the gray and white matter. Western blot analysis of acidic proteins from the brains and spinal cords of EAE mice had higher levels of multiple citrullinated GFAP isoforms compared with controls, with more F95-positive bands in the EAE brains vs. spinal cords. These results raise the possibility that citrullination of both GFAP and MBP may contribute to the pathophysiology of EAE and that the brains of EAE mice may contain more pathology than previously realized.

Increased peptidylarginine deiminase type II in hypoxic astrocytes

Peptidylarginine deiminase type II (PAD 2) is the primary enzyme responsible for conversion of protein bound arginine to citrulline in the central nervous system. Evidence suggests that glial fibrillary acidic protein (GFAP), the main intermediate filament in astrocytes, is deiminated, but not much is known regarding factors that control this enzymatic reaction. The present study demonstrated that PAD 2 activity (as determined by Western blot analysis of citrullinated GFAP isoforms) was increased in human cultured astrocytes by hypoxic conditions. PAD 2 mRNA increased markedly during the first 2h of hypoxia, but using a single chain antibody against human PAD 2 produced from the ETH-2 phage library, it took approximately 8h of hypoxia to see marked increases in PAD 2 protein. Thus, this is the first report to demonstrate a measurable response in the amounts of PAD 2 mRNA, protein and activity in human astrocytes by prolonged hypoxic exposure.

Clinical signs and symptoms in a large hereditary spastic paraparesis pedigree with a novel spastin mutation

The most common form of autosomal dominant hereditary spastic paraparesis (HSP), SPG4, is caused by mutations in the spastin gene on chromosome 2p. This disease is characterized by intra- and interfamilial phenotypic variation. To determine the predictive values of clinical signs and symptoms in SPG4, we examined 43 members of a large pedigree with autosomal dominant HSP. We then identified the genetic etiology of the disorder in this family, a novel nonsense mutation in exon 1 of spastin, carried by 24 of the examined family members. The best clinical predictors of positive gene status were the presence of hyperreflexia in the lower extremities, >2 beats of ankle clonus, pes cavus, bladder symptoms and increased tone in the legs. The mean age of onset was 32.2 +/- 7.4 years, but the age of onset was earlier in children from 10 of 12 child-parent gene-positive pairs, with a mean difference of 10.8 +/- 3.3 years. The finding of leg weakness was especially common in older-onset affected family member with leg hyperreflexia. These results suggest that specific clinical signs and symptoms may be of value in differentiating individuals affected with SPG4 from family members with nonspecific neurological findings.

Increased citrullinated glial fibrillary acidic protein in secondary progressive multiple sclerosis

In this study, we demonstrate that grossly unaffected white matter from secondary progressive multiple sclerosis (SP-MS) patients is heavily citrullinated, as compared to normal white matter from control patients. Citrullination was most pronounced at plaque interfaces and was shown to colocalize with glial fibrillary acidic protein (GFAP)-immunoreactivity using dual color immunofluorescence. In contrast, the plaques themselves weakly stained for citrullinated proteins compared to control white matter and usually contained a blood vessel with surrounding astrocytes that were positive both for citrullinated proteins and GFAP. In SP-MS brain samples, but not in normal brains, long fibers of colocalized GFAP- and citrullinated proteins extended into the gray matter. Increased numbers of astrocytes containing citrullinated proteins and GFAP were also present at the junction between the gray and white matter in SP-MS brains. Western blot analysis of acidic brain proteins from nonplaque-containing white matter showed upregulation of multiple citrullinated GFAP proteins in SP-MS brains as compared to controls. Our results demonstrate that increased amounts of citrullinated GFAP are present in SP-MS brains, but also shows that these proteins are present in areas of MS brains that were grossly normal appearing. These data raise the possibility that citrullination of GFAP contributes to the pathophysiology of MS.

Immunohistochemical localization of citrullinated proteins in adult rat brain

By using hybridoma technology, an IgM monoclonal antibody (F95) against multiple citrullinated synthetic and natural peptides was recently developed and used to stain immunohistochemically subsets of astrocytes and myelin basic protein (MBP) from selected regions of human brain (Nicholas and Whitaker [2002] Glia 37:328-336). With this antibody, the present study provides a more detailed localization of citrullinated epitopes in the central nervous system (CNS) by examining immunohistochemical staining patterns for F95 in the normal adult rat brain. Thus, immunohistochemical labeling for citrullinated epitopes was seen in white matter areas consistent with myelin staining; however, in general, it was more prominent and uniform in the caudal CNS (spinal cord, medulla oblongata, pons, and cerebellum) than in more rostral areas. F95 staining was also seen in cells and fibers often intimately associated with blood vessels and/or ventricular surfaces. By using dual-color immunofluorescence, the vast majority of this latter staining was colocalized within a subset of astrocytes also immunoreactive for glial fibrillary acidic protein (GFAP). By using Western blot analysis of rat brain proteins, multiple GFAP- and MBP-immunoreactive proteins and peptide fragments were seen, and many of them were also reactive with the F95 antibody. Thus, the present study not only demonstrates that citrullinated epitopes in normal rat brain are most concentrated in subsets of myelin and astrocytes but also provides evidence that GFAP, like MBP, may be present as multiple citrullinated isoforms.

The fate of biodegradable microspheres injected into rat brain

Biodegradable microspheres made with poly-[D,L-lactide-co-glycolide] represent an evolving technology for drug delivery into the central nervous system. Even though these microspheres have been shown to be engulfed by astrocytes in vitro, the purpose of the present study was to track the fate of biodegradable microspheres in vivo. This was accomplished using microspheres containing the fluorescent dye coumarin-6 followed 1 day, 1 week and 1 month after intracerebral injections of this material were made into the rat brain. Using dual color immunohistochemistry and antisera against glial fibrillary acidic protein for astrocytes versus phosphotyrosine for microglia, results demonstrate that phagocytosis of small coumarin-containing microspheres <7.5 microm in diameter was primarily by microglia in vivo during the first week post-injection. In contrast, only a small minority of these microspheres appeared to be engulfed by astrocytes.

Preparation of a monoclonal antibody to citrullinated epitopes: its characterization and some applications to immunohistochemistry in human brain

Using hybridoma technology, an IgM monoclonal antibody (mAb), designated as F95, was developed against a deca-citrullinated peptide (DCP) consisting of 10 citrulline residues and a carboxyl Gly-Gly-Cys through which DCP was covalently linked to an activated carrier protein, keyhole limpet hemocyanin (KLH). Clones were selected on the basis of not reacting with human unmodified and noncitrullinated myelin basic protein (MBP), MBP-C1, but reacting well with human citrullinated MBP (MBP-C8). When tested by ELISA, this mAb demonstrated minimal reactivity with human MBP-C1, varying reactivity with the C2-C5 isomers of human MBP, moderate binding with guinea pig MBP-C8, and strong reactivity with human MBP-C8. By ELISA, mAb F95 was directed predominantly against citrulline, not MBP, as revealed by its binding to DCP linked with activated KLH, bovine serum albumin (BSA), or ovalbumin (OA), but not with KLH, BSA, or OA alone. Immunohistochemistry of normal human brain demonstrated that F95 stained central nervous system myelin and a subset of astrocytes. Given the citrulline-directed features of mAb F95, this immunohistochemical pattern suggests that certain astroglial filaments expressing glial fibrillary acidic protein also contain citrulline-bearing components. These potentially implicate citrullinated proteins, notably in astroglial filaments, in a variety of normal and pathological neurobiological processes.

Multiple messengers in descending serotonin neurons: localization and functional implications

In the present review article we summarize mainly histochemical work dealing with descending bulbospinal serotonin neurons which also express a number of neuropeptides, in particular substance P and thyrotropin releasing hormone. Such neurons have been observed both in rat, cat and monkey, and may preferentially innervate the ventral horns of the spinal cord, whereas the serotonin projections to the dorsal horn seem to lack these coexisting peptides. More recent studies indicate that a small population of medullary raphe serotonin neurons, especially at rostral levels, also synthesize the inhibitory neurotransmitter gamma-amino butyric acid (GABA). Many serotonin neurons contain the glutamate synthesizing enzyme glutaminase and can be labelled with antibodies raised against glutamate, suggesting that one and the same neuron may release several signalling substances, causing a wide spectrum of post- (and pre-) synaptic actions.

An immunohistochemical investigation of the opioid cell column in lamina X of the male rat lumbosacral spinal cord

Tri-color immunohistochemistry was employed to examine enkephalin-like immunoreactive neurons in lamina X of the rat lumbosacral spinal cord. Serial coronal sections from levels L1 to S3 were examined. A rostral group of large (40-50 microm diameter), pyramidal-shaped enkephalin-like immunoreactive neurons were shown from levels L1 to L4-5. Essentially all of these neurons were also immunoreactive for galanin and cholecystokinin. A second enkephalin-like immunoreactive cell group, extending from L5 to approximately the S2-3 level, contained smaller (20-30 microm diameter), ovoid-shaped perikaryia. Approximately 75% of these enkephalin-like immunoreactive neurons were also immunoreactive for neuropeptide Y. Neurotensin-immunoreactivity was also present in this area, having varying amounts of co-localization with these other two peptides. These results demonstrate that the lumbosacral opioid cell column in lamina X is not a neurochemically homogenous structure.

Stiff-persons' syndrome associated with thymoma and subsequent myasthenia gravis

We report the first case of stiff-persons' (-man) syndrome in the setting of a histologically proven thymoma. Muscular hyperactivity was abolished under general anesthesia and the symptoms of stiffness resolved after thymectomy and three courses of intravenous immunoglobulins. After thymectomy, the patient developed ocular myasthenia gravis which later resolved spontaneously. We suggest that thymoma be sought for in cases with neuromuscular hyperactivity syndromes. Myasthenia gravis may develop subsequently in these cases.