Synovial membrane protein expression differs between juvenile idiopathic arthritis subtypes in early disease.

INTRODUCTION: Juvenile idiopathic arthritis (JIA) is the most common rheumatological disease of childhood with a prevalence of around 1 in 1,000. Without appropriate treatment it can have devastating consequences including permanent disability from joint destruction and growth deformities. Disease aetiology remains unknown. Investigation of disease pathology at the level of the synovial membrane is required if we want to begin to understand the disease at the molecular and biochemical level. The synovial membrane proteome from early disease-stage, treatment naive JIA patients was compared between polyarticular and oligoarticular subgroups. METHODS: Protein was extracted from 15 newly diagnosed, treatment naive JIA synovial membrane biopsies and separated by two dimensional fluorescent difference in-gel electrophoresis. Proteins displaying a two-fold or greater change in expression levels between the two subgroups were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry with expression further verified by Western blotting and immunohistochemistry. RESULTS: Analysis of variance analysis (P ≤ 0.05) revealed 25 protein spots with a two-fold or greater difference in expression levels between polyarticular and oligoarticular patients. Hierarchical cluster analysis with Pearson ranked correlation revealed two distinctive clusters of proteins. Some of the proteins that were differentially expressed included: integrin alpha 2b (P = 0.04); fibrinogen D fragment (P = 0.005); collagen type VI (P = 0.03); fibrinogen gamma chain (P = 0.05) and peroxiredoxin 2 (P = 0.02). The identified proteins are involved in a number of different processes including platelet activation and the coagulation system. CONCLUSIONS: The data indicate distinct synovial membrane proteome profiles between JIA subgroups at an early stage in the disease process. The identified proteins also provide insight into differentially perturbed pathways which could influence pathological events at the joint level.

Growth hormone, gender and face shape in Prader-Willi syndrome.

Prader-Willi syndrome is a neurodevelopmental disorder resulting from the absence of expression of paternally expressed gene(s) in a highly imprinted region of chromosome 15q11-13. The physical phenotype includes evidence of growth retardation due to relative growth hormone deficiency, small hands and feet, a failure of normal secondary sexual development, and a facial appearance including narrow bifrontal diameter, almond-shaped palpebral fissures, narrow nasal root, and thin upper vermilion with downturned corners of the mouth. Anecdotally, the face of individuals with PWS receiving hGH treatment is said to "normalize." We used dense surface modelling and shape signature techniques to analyze 3D photogrammetric images of the faces of 72 affected and 388 unaffected individuals. We confirmed that adults with Prader-Willi syndrome who had never received human growth supplementation displayed known characteristic facial features. Facial growth was significantly reduced in these adults, especially in males. We demonstrated that following human growth hormone (hGH) supplementation, vertical facial growth of affected individuals falls within the normal range. However, lateral and periorbital face shape and nose shape differences in affected children who have received hGH therapy remain sufficiently strong to be significantly discriminating in comparisons with age-sex matched, unaffected individuals. Finally, we produced evidence that age at initiation and length of treatment with hGH do not appear to play a role in normalization or in consistent alteration of the face shape of affected individuals. This is the first study to provide objective shape analysis of craniofacial effects of hGH therapy in Prader-Willi syndrome.

Adaptation to experimental jet-lag in R6/2 mice despite circadian dysrhythmia.

The R6/2 transgenic mouse model of Huntington's disease (HD) shows a disintegration of circadian rhythms that can be delayed by pharmacological and non-pharmacological means. Since the molecular machinery underlying the circadian clocks is intact, albeit progressively dysfunctional, we wondered if light phase shifts could modulate the deterioration in daily rhythms in R6/2 mice. Mice were subjected to four x 4 hour advances in light onset. R6/2 mice adapted to phase advances, although angles of entrainment increased with age. A second cohort was subjected to a jet-lag paradigm (6 hour delay or advance in light onset, then reversal after 2 weeks). R6/2 mice adapted to the original shift, but could not adjust accurately to the reversal. Interestingly, phase shifts ameliorated the circadian rhythm breakdown seen in R6/2 mice under normal LD conditions. Our previous finding that the circadian period (tau) of 16 week old R6/2 mice shortens to approximately 23 hours may explain how they adapt to phase advances and maintain regular circadian rhythms. We tested this using a 23 hour period light/dark cycle. R6/2 mice entrained to this cycle, but onsets of activity continued to advance, and circadian rhythms still disintegrated. Therefore, the beneficial effects of phase-shifting are not due solely to the light cycle being closer to the tau of the mice. Our data show that R6/2 mice can adapt to changes in the LD schedule, even beyond the age when their circadian rhythms would normally disintegrate. Nevertheless, they show abnormal responses to changes in light cycles. These might be caused by a shortened tau, impaired photic re-synchronization, impaired light detection and/or reduced masking by evening light. If similar abnormalities are present in HD patients, they may suffer exaggerated jet-lag. Since the underlying molecular clock mechanism remains intact, light may be a useful treatment for circadian dysfunction in HD.

Participant experience of invasive research in adults with intellectual disability.

Clinical research is a necessity if effective and safe treatments are to be developed. However, this may well include the need for research that is best described as 'invasive' in that it may be associated with some discomfort or inconvenience. Limitations in the undertaking of invasive research involving people with intellectual disabilities (ID) are perhaps related to anxieties within the academic community and among ethics committees; however, the consequence of this neglect is that innovative treatments specific to people with ID may not be developed. Such concerns are likely to continue while there is limited published knowledge regarding the actual experiences of people with ID who have participated in invasive clinical research. As part of a pilot study trialling the novel use of a surgically inserted device to curb overeating in people with Prader-Willi syndrome (PWS) we have investigated the experience of research through semistructured qualitative interviews involving three participants and their carers. Thematic analysis revealed that the adults with PWS and their family carers rated their participation positively, seeing it as a rewarding and enriching experience. This brief report discusses findings from our interview data in order to highlight strategies which may ensure that research is acceptable to participants, meets the necessary ethical standards and is able to achieve the aims set out by the researchers. To our knowledge, this is the first study to record experiences directly from people with PWS and their carers regarding their involvement in invasive clinical research.

Defective mitochondrial function in vivo in skeletal muscle in adults with Down's syndrome: a 31P-MRS study.

Down's syndrome (DS) is a developmental disorder associated with intellectual disability (ID). We have previously shown that people with DS engage in very low levels of exercise compared to people with ID not due to DS. Many aspects of the DS phenotype, such as dementia, low activity levels and poor muscle tone, are shared with disorders of mitochondrial origin, and mitochondrial dysfunction has been demonstrated in cultured DS tissue. We undertook a phosphorus magnetic resonance spectroscopy ((31)P-MRS) study in the quadriceps muscle of 14 people with DS and 11 non-DS ID controls to investigate the post-exercise resynthesis kinetics of phosphocreatine (PCr), which relies on mitochondrial respiratory function and yields a measure of muscle mitochondrial function in vivo. We found that the PCr recovery rate constant was significantly decreased in adults with DS compared to non-DS ID controls (1.7 ± 0.1 min(-1) vs 2.1 ± 0.1 min(-1) respectively) who were matched for physical activity levels, indicating that muscle mitochondrial function in vivo is impaired in DS. This is the first study to investigate mitochondrial function in vivo in DS using (31)P-MRS. Our study is consistent with previous in vitro studies, supporting a theory of a global mitochondrial defect in DS.

Vitamin D binding protein isoforms as candidate predictors of disease extension in childhood arthritis.

INTRODUCTION: Juvenile idiopathic arthritis (JIA) comprises a poorly understood group of chronic autoimmune diseases with variable clinical outcomes. We investigated whether the synovial fluid (SF) proteome could distinguish a subset of patients in whom disease extends to affect a large number of joints. METHODS: SF samples from 57 patients were obtained around time of initial diagnosis of JIA, labeled with Cy dyes and separated by two-dimensional electrophoresis. Multivariate analyses were used to isolate a panel of proteins which distinguish patient subgroups. Proteins were identified using MALDI-TOF mass spectrometry with expression verified by immunochemical methods. Protein glycosylation status was confirmed by hydrophilic interaction liquid chromatography. RESULTS: A truncated isoform of vitamin D binding protein (VDBP) is present at significantly reduced levels in the SF of oligoarticular patients at risk of disease extension, relative to other subgroups (p<0.05). Furthermore, sialylated forms of immunopurified synovial VDBP were significantly reduced in extended oligoarticular patients (p<0.005). CONCLUSION: Reduced conversion of VDBP to a macrophage activation factor may be used to stratify patients to determine risk of disease extension in JIA patients.

Atypical movement performance and sensory integration in Asperger's syndrome.

The aims of this study were to investigate whether individuals with AS have impaired motor abilities and sensorimotor processing and whether these impairments were age-related. Sensorimotor abilities were examined using the Movement Assessment Battery for Children-2, and the Sensory Integration Praxis Test. Fifty boys with AS aged 7-14 years old were compared with typically developing boys. Overall, children with AS showed significant impairment of movement performance as well as proprioceptive and vestibular processing. There were no interaction effects of age and clinical group on level of performance deficit in any of the modalities tested. Increasing our understanding of motor and sensory impairment in AS could have treatment implications for those supporting individuals with AS.

Synovial membrane immunohistology in early untreated juvenile idiopathic arthritis: differences between clinical subgroups.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) consists of a heterogeneous group of inflammatory disorders, within which there are a number of clinical subgroups. Diagnosis and assignment to a particular subgroup can be problematical and more concise methods of subgroup classification are required. This study of the synovial membrane characterises the immunohistochemical features in early untreated, newly diagnosed JIA and compares findings with disease subgroup at 2 years. METHODS: 42 patients with newly diagnosed untreated JIA underwent synovial biopsy before the administration of steroids or disease-modifying antirheumatic drugs. Patients were classified as either polyarticular, persistent oligoarticular or extended-to-be oligoarticular. The location and semiquantitative analysis of T-cell subsets, B cells, macrophages and blood vessels were determined using immunohistochemistry. RESULTS: Synovial hyperplasia varied significantly between the three groups (p<0.0001). There was a significant difference in the CD3 T-cell population between the three groups (p=0.004) and between the extended-to-be and persistent group (p=0.032). CD4 expression was significantly higher in the poly and extended-to-be oligo groups (p=0.002), again the extended-to-be group had more CD4 T cells than the persistent group (p=0.008). B-cell infiltrates were more marked in the polyarticular group and were significantly higher in the extended-to-be group compared with the persistent group (p=0.005). Vascularisation was more pronounced in the polyarticular and extended-to-be oligoarticular groups, the extended-to-be group had significantly more vascularisation than the persistent group (p=0.0002). CONCLUSIONS: There are significant differences in the histomorphometric features of synovial tissue between patient subgroups. Immunohistological examination of synovial membrane biopsies may provide further insight into early disease processes in JIA.

Asymptomatic sleep abnormalities are a common early feature in patients with Huntington's disease.

Huntington's disease (HD) is a fatal neurodegenerative disease characterized by motor, cognitive, and psychiatric disturbance. In this article, we used polysomnography, actigraphy and a variety of validated questionnaires to ascertain the extent to which sleep changes are identifiable and measurable in mild stage HD, and importantly, to see whether patients are negatively impacted by the changes in their sleep. We found significant differences in sleep architecture and sleep efficiency in patients compared with controls using polysomnography. However, patient scores on the Functional Outcomes of Sleep Questionnaire, Medical Outcomes of Sleep Scale, and Epworth Sleepiness Scale were not significantly different to controls. These results suggest that although marked changes in sleep architecture are present in early HD and can be detected using polysomnography, patients do not necessarily recognize or report these abnormalities.

Prospective evaluation of clinical and ultrasound findings in ankle disease in juvenile idiopathic arthritis: importance of ankle ultrasound.

OBJECTIVE: To prospectively compare clinical examination of the ankle structures with ultrasound (US) findings. METHODS: In 42 children with juvenile idiopathic arthritis (JIA; 25 girls, 17 boys, mean age 11.3 yrs, range 2.3-22.3 yrs), a total of 61 swollen/painful ankles were assessed clinically and ultrasonographically. Accurate clinical examination of the entire ankle joint was performed, focusing especially on 3 regions - tibiotalar joint and medial and lateral tendons. Clinical and US findings were both scored 0-3 (normal-severe). RESULTS: US demonstrated no signs of tibiotalar joint effusion in 14 out of 43 ankles considered clinically involved. For the medial tendons, US showed tenosynovitis in 13 ankles out of 31 thought to be clinically normal; and for the lateral tendons, of the 19 deemed to be clinically involved, less than 50% had involvement on US. Very poor agreement was observed comparing the clinical and US scores for the 3 regions: tibiotalar joint, kappa = 0.3; medial tendons, kappa = 0.24; lateral tendons, kappa = 0.25. With regard to other ankle structures, only 39% of the subtalar (talocalcaneal) joints considered clinically involved were deemed abnormal on US. Finally, of the 10 ankles with talonavicular US effusion, only 2 were considered clinically involved. CONCLUSION: Using US findings as the "gold standard," clinical examination of the ankle in children with JIA was found to be inadequate in identifying the structures involved. US assessment prior to any glucocorticoid injection should be considered to improve the outcome. A prospective study comparing the outcome following clinical- versus US-guided ankle joint injection should be undertaken, to confirm our findings.

Disruption of peripheral circadian timekeeping in a mouse model of Huntington's disease and its restoration by temporally scheduled feeding.

Behavioral circadian rhythms disintegrate progressively in the R6/2 mouse model of Huntington's disease (HD), recapitulating the sleep-wake disturbance seen in HD patients. Here we show that disturbances in circadian pacemaking are not restricted to the brain, but also encompass peripheral metabolic pathways in R6/2 mice. Notably, circadian rhythms of clock-driven genes that are key metabolic outputs in the liver are abolished in vivo. This deficiency is accompanied by arrhythmic expression of the clock genes Cry1 and Dbp, and a phase-advanced Per2 cycle. Compromised circadian metabolic cycles are not, however, a consequence of deficient pacemaking intrinsic to the liver, because when cultured in vitro, R6/2 liver slices exhibit self-sustained circadian bioluminescence rhythms. We therefore propose that compromised metabolic cycles arise from an internal desynchronization secondary to altered feeding patterns and impaired circadian signaling from the central pacemaker of the suprachiasmatic nucleus (SCN). Importantly, the SCN-independent food-entrainable oscillator remains intact in R6/2 mice and, when invoked, can restore daily behavioral cycles and reverse some of the metabolic abnormalities seen in the liver. Disturbances of metabolism have long been thought to be an important feature of HD. Uncoupling liver metabolism from circadian drives will reduce metabolic efficiency and cause imbalances in metabolites known to be deleterious to brain function. Thus, even subtle imbalances in liver function may exacerbate symptoms of HD, where neurological function is already compromised.

Responses to environmental enrichment differ with sex and genotype in a transgenic mouse model of Huntington's disease.

BACKGROUND: Environmental enrichment (EE) in laboratory animals improves neurological function and motor/cognitive performance, and is proposed as a strategy for treating neurodegenerative diseases. EE has been investigated in the R6/2 mouse model of Huntington's disease (HD), where increased social interaction, sensory stimulation, exploration, and physical activity improved survival. We have also shown previously that HD patients and R6/2 mice have disrupted circadian rhythms, treatment of which may improve cognition, general health, and survival. METHODOLOGY/PRINCIPAL FINDINGS: We examined the effects of EE on the behavioral phenotype and circadian activity of R6/2 mice. Our mice are typically housed in an "enriched" environment, so the EE that the mice received was in addition to these enhanced housing conditions. Mice were either kept in their home cages or exposed daily to the EE (a large playground box containing running wheels and other toys). The "home cage" and "playground" groups were subdivided into "handling" (stimulated throughout the experimental period) and "no-handling" groups. All mice were assessed for survival, body weight, and cognitive performance in the Morris water maze (MWM). Mice in the playground groups were more active throughout the enrichment period than home cage mice. Furthermore, R6/2 mice in the EE/no-handling groups had better survival than those in the home cage/no-handling groups. Sex differences were seen in response to EE. Handling was detrimental to R6/2 female mice, but EE increased the body weight of male R6/2 and WT mice in the handling group. EE combined with handling significantly improved MWM performance in female, but not male, R6/2 mice. CONCLUSIONS/SIGNIFICANCE: We show that even when mice are living in an enriched home cage, further EE had beneficial effects. However, the improvements in cognition and survival vary with sex and genotype. These results indicate that EE may improve the quality of life of HD patients, but we suggest that EE as a therapy should be tailored to individuals.

The transition between the phenotypes of Prader-Willi syndrome during infancy and early childhood.

AIM: Prader-Willi syndrome (PWS) is a genetic disorder historically characterized by two phenotypic stages. The early phenotype in infants is associated with hypotonia, poor suck, and failure to thrive. In later childhood, PWS is associated with intellectual disability, hyperphagia, as well as growth and sex hormone deficiency. Little is known about the transition between phenotypes. This study investigates the nature of the change in infancy and childhood PWS. METHOD: Forty-six children (22 females, 24 males; mean age 2 y 9 mo, SD 18.9 mo; range 7 mo-5 y) with genetically confirmed PWS participated. Information was obtained on childhood height and weight, and eating behaviour from case notes and by parental interview. RESULTS: Weight standard deviation scores (SDS) started to exceed height by the end of the first year. Height SDS appeared to fall from near normal at birth until stabilizing below normal around 2 years. Half of the children whose body mass index (BMI) was higher than normal at interview had food interests greater than that of their peers, and the age at which increased age-appropriate eating was first noted was later than the increase of BMI SDS. INTERPRETATION: Obesity may develop before the increased interest in food, suggesting underlying physiological factors independent of appetite control may be important.

Stratification and monitoring of juvenile idiopathic arthritis patients by synovial proteome analysis.

Juvenile idiopathic arthritis (JIA) comprises a poorly understood group of chronic, childhood onset, autoimmune diseases with variable clinical outcomes. We investigated whether profiling of the synovial fluid (SF) proteome by a fluorescent dye based, two-dimensional gel (DIGE) approach could distinguish patients in whom inflammation extends to affect a large number of joints, early in the disease process. SF samples from 22 JIA patients were analyzed: 10 with oligoarticular arthritis, 5 extended oligoarticular and 7 polyarticular disease. SF samples were labeled with Cy dyes and separated by two-dimensional electrophoresis. Multivariate analyses were used to isolate a panel of proteins which distinguish patient subgroups. Proteins were identified using MALDI-TOF mass spectrometry with expression further verified by Western immunoblotting and immunohistochemistry. Hierarchical clustering based on the expression levels of a set of 40 proteins segregated the extended oligoarticular from the oligoarticular patients (p < 0.05). Expression patterns of the isolated protein panel have also been observed over time, as disease spreads to multiple joints. The data indicates that synovial fluid proteome profiles could be used to stratify patients based on risk of disease extension. These protein profiles may also assist in monitoring therapeutic responses over time and help predict joint damage.

Ankle disease in juvenile idiopathic arthritis: ultrasound findings in clinically swollen ankles.

OBJECTIVE: The ankle joint is frequently involved in juvenile idiopathic arthritis (JIA), but it is unclear whether this is predominantly due to synovitis, tenosynovitis, or both. We performed clinic-based ultrasound examination to assess the prevalence of synovitis and tenosynovitis in children with JIA felt clinically to have active inflammatory disease of the ankle. METHODS: Thirty-four patients with 49 clinically swollen ankles were studied (19 polyarticular JIA, 13 oligoarticular JIA, 1 systemic JIA, 1 psoriatic JIA). All cases had at least one clinically swollen ankle joint. The children were assessed clinically and had ultrasound examination during routine clinic appointments. RESULTS: We found 71% of ankles had tenosynovitis and 39% had tenosynovitis alone. Only 29% of swollen ankles had a tibiotalar effusion alone. We found 33% had both tenosynovitis and a tibiotalar effusion. When results were analyzed by JIA subtype, we found 81% of oligoarticular JIA ankles had medial ankle tenosynovitis but only 19% had tibiotalar effusion alone. There was a significant difference between JIA subgroups for the frequency of occurrence of medial ankle tenosynovitis (p = 0.048) and lateral ankle tenosynovitis (p = 0.001). CONCLUSION: The tibiotalar joint was not involved in 39% of the swollen ankles; and tenosynovitis, sometimes in isolation, was the dominant finding. This has implications for therapeutic intervention and also for an improved classification of children with JIA, especially with ankle involvement.

Comparative analysis of synovial fluid and plasma proteomes in juvenile arthritis--proteomic patterns of joint inflammation in early stage disease.

Synovial fluid is a potential source of novel biomarkers for many arthritic disorders involving joint inflammation, including juvenile idiopathic arthritis. We first compared the distinctive protein 'fingerprints' of local inflammation in synovial fluid with systemic profiles within matched plasma samples. The synovial fluid proteome at the time of joint inflammation was then evaluated across clinical subgroups to identify early disease associated proteins. We measured the synovial fluid and plasma proteomes using the two-dimensional fluorescence difference gel electrophoresis approach. Image analysis software was used to highlight the expression levels of joint and subgroup associated proteins across the study cohort (n = 32). A defined subset of 30 proteins had statistically significant differences (p < 0.05) between sample types such that synovial fluid could be differentiated from plasma. Furthermore distinctive synovial proteome expression patterns segregate patient subgroups. Protein expression patterns localized in the chronically inflamed joint therefore have the potential to identify patients more likely to suffer disease which will spread from a single joint to multiple joints. The proteins identified could act as criteria to prevent disease extension by more aggressive therapeutic intervention directed at an earlier stage than is currently possible.

Proteomic analysis of recurrent joint inflammation in juvenile idiopathic arthritis.

The synovial fluid proteome in juvenile idiopathic arthritis was investigated to isolate joint-specific biomarkers that are expressed in patients displaying recurrent joint inflammation. To identify the synovial specific proteome, matched synovial fluid and plasma samples were subjected to protein separation by 2-dimension electrophoresis (2DE). Forty-three protein spots, overexpressed in the joint, were identified. Synovial fluids from children with single-event knee joint inflammation were then compared with a group with recurrent knee disease. Nine synovial specific proteins were significantly differentially expressed in the recurrent group. Proteolytic fragments of collagen X, fibrin beta-chain, and T-cell receptor alpha-region have been identified among this protein cluster. Putative biomarkers, overexpressed in the joint and differentially expressed in children with recurrent joint inflammation, have been identified. These proteins may play a significant role determining the pathological state within the chronically inflamed joint and influence disease progression in JIA. This is the first study of the synovial proteome in children.