Pluripotential GluN1 (NMDA NR1): Functional Significance in Cellular Nuclei in Pain/Nociception.

The N-methyl-D-aspartate (NMDA) glutamate receptors function as plasma membrane ionic channels and take part in very tightly controlled cellular processes activating neurogenic and inflammatory pathways. In particular, the NR1 subunit (new terminology: GluN1) is required for many neuronal and non-neuronal cell functions, including plasticity, survival, and differentiation. Physiologic levels of glutamate agonists and NMDA receptor activation are required for normal neuronal functions such as neuronal development, learning, and memory. When glutamate receptor agonists are present in excess, binding to NMDA receptors produces neuronal/CNS/PNS long-term potentiation, conditions of acute pain, ongoing severe intractable pain, and potential excitotoxicity and pathology. The GluNR1 subunit (116 kD) is necessary as the anchor component directing ion channel heterodimer formation, cellular trafficking, and the nuclear localization that directs functionally specific heterodimer formation, cellular trafficking, and nuclear functions. Emerging studies report the relevance of GluN1 subunit composition and specifically that nuclear GluN1 has major physiologic potential in tissue and/or subnuclear functioning assignments. The shift of the GluN1 subunit from a surface cell membrane to nuclear localization assigns the GluN1 promoter immediate early gene behavior with access to nuclear and potentially nucleolar functions. The present narrative review addresses the nuclear translocation of GluN1, focusing particularly on examples of the role of GluN1 in nociceptive processes.

Pre-Diagnosis Pain in Patients With Pancreatic Cancer Signals the Need for Aggressive Symptom Management.

OBJECTIVE: This study assessed the impact of pancreatic cancer (PC) pain on associated symptoms, activities, and resource utilization from 2016 to 2020 in an online patient registry. PATIENTS AND METHODS: Responses from PC patient volunteers (N = 1978) were analyzed from online surveys in a cross-sectional study. Comparisons were performed between PC patient groups reporting, (1) the presence vs. absence of pre-diagnosis PC pain, (2) high (4-8) vs. low (0-3) pain intensity scores on an 11-point numerical rating scale (NRS), and (3) year of PC diagnosis (2010-2020). Descriptive statistics and all bivariate analyses were performed using Chi-square or Fisher's Exact tests. RESULTS: PC pain was the most frequently reported pre-diagnosis symptom (62%). Pre-diagnostic PC pain was reported more frequently by women, those with a younger age at diagnosis, and those with PC that spread to the liver and peritoneum. Those with pre-diagnostic PC pain vs. those without reported higher pain intensities (2.64 ± 2.54 vs.1.56 ± 2.01 NRS mean ± SD, respectively, P = .0039); increased frequencies of post-diagnosis symptoms of cramping after meals, feelings of indigestion, and weight loss (P = .02-.0001); and increased resource utilization in PC pain management: (ER visits N = 86 vs. N = 6, P = .018 and analgesic prescriptions, P < .03). The frequency of high pain intensity scores was not decreased over a recent 11-year span. CONCLUSIONS: PC pain continues to be a prominent PC symptom. Patients reporting pre-diagnosis PC pain experience increased GI metastasis, symptoms burden, and are often undertreated. Its mitigation may require novel treatments, more resources dedicated to ongoing pain management and surveillance to improve outcomes.

Tyrosine Kinase Inhibitors Reduce NMDA NR1 Subunit Expression, Nuclear Translocation, and Behavioral Pain Measures in Experimental Arthritis.

In the lumbar spinal cord dorsal horn, release of afferent nerve glutamate activates the neurons that relay information about injury pain. Here, we examined the effects of protein tyrosine kinase (PTK) inhibition on NMDA receptor NR1 subunit protein expression and subcellular localization in an acute experimental arthritis model. PTK inhibitors genistein and lavendustin A reduced cellular histological translocation of NMDA NR1 in the spinal cord occurring after the inflammatory insult and the nociceptive behavioral responses to heat. The PTK inhibitors were administered into lumbar spinal cord by microdialysis, and secondary heat hyperalgesia was determined using the Hargreaves test. NMDA NR1 cellular protein expression and nuclear translocation were determined by immunocytochemical localization with light and electron microscopy, as well as with Western blot analysis utilizing both C- and N-terminal antibodies. Genistein and lavendustin A (but not inactive lavendustin B or diadzein) effectively reduced (i) pain related behavior, (ii) NMDA NR1 subunit expression increases in spinal cord, and (iii) the shift of NR1 from a cell membrane to a nuclear localization. Genistein pre-treatment reduced these events that occur in vivo within 4 h after inflammatory insult to the knee joint with kaolin and carrageenan (k/c). Cycloheximide reduced glutamate activated upregulation of NR1 content confirming synthesis of new protein in response to the inflammatory insult. In addition to this in vivo data, genistein or staurosporin inhibited upregulation of NMDA NR1 protein and nuclear translocation in vitro after treatment of human neuroblastoma clonal cell cultures (SH-SY5Y) with glutamate or NMDA (4 h). These studies provide evidence that inflammatory activation of peripheral nerves initiates increase in NMDA NR1 in the spinal cord coincident with development of pain related behaviors through glutamate non-receptor, PTK dependent cascades.

Predictors of Hand Contracture in Early Systemic Sclerosis and the Effect on Function: A Prospective Study of the GENISOS Cohort.

OBJECTIVE: To identify baseline features that predict progression of hand contractures and to assess the effect of contractures on functional status in the prospective GENISOS cohort. METHODS: Rate of decline in hand extension, as an indicator of hand contracture, was the primary outcome. We assessed longitudinal hand extension measurements, modified Health Assessment Questionnaire (MHAQ) score, Medical Outcomes Study Short Form-36 (SF-36) physical function score, and demographic, clinical, and serological variables. Subjects with ≥ 2 hand measurements at least 6 months apart were included. RESULTS: A total of 1087 hand measurements for 219 patients were available over an average of 8.1 ± 4.8 years. Hand extension decreased on average by 0.11 cm/year. Antitopoisomerase I antibody (ATA) positivity and higher modified Rodnan Skin Score (mRSS) were predictive of faster decline in hand extension (p = 0.009 and p = 0.046, respectively). In a subgroup analysis of 62 patients with ≤ 2 years from SSc onset, ATA and diffuse disease type were associated with faster decline in hand extension; anticentromere positivity was associated with slower rate of decline. Although the rate of decline in patients with disease duration ≤ 2 years was numerically higher, the difference was not statistically significant. Hand extension continued to decline in a linear fashion over time and was inversely related to overall functional status. CONCLUSION: ATA was predictive of contracture development in both early disease (≤ 2 yrs) and in the overall cohort. Hand extension declined linearly over time and was inversely associated with MHAQ and SF-36 scores. ATA positivity and higher baseline mRSS were predictive of faster decline in hand extension.

Applications of Bayesian statistical methodology to clinical trial design: A case study of a phase 2 trial with an interim futility assessment in patients with knee osteoarthritis.

Development of new pharmacological treatments for osteoarthritis that address unmet medical needs in a competitive market place is challenging. Bayesian approaches to trial design offer advantages in defining treatment benefits by addressing clinically relevant magnitude of effects relative to comparators and in optimizing efficiency in analysis. Such advantages are illustrated by a motivating case study, a proof of concept, and dose finding study in patients with osteoarthritis. Patients with osteoarthritis were randomized to receive placebo, celecoxib, or 1 of 4 doses of galcanezumab. Primary outcome measure was change from baseline WOMAC pain after 8 weeks of treatment. Literature review of clinical trials with targeted comparator therapies quantified treatment effects versus placebo. Two success criteria were defined: one to address superiority to placebo with adequate precision and another to ensure a clinically relevant treatment effect. Trial simulations used a Bayesian dose response and longitudinal model. An interim analysis for futility was incorporated. Simulations indicated the study had ≥85% power to detect a 14-mm improvement and ≤1% risk for a placebo-like drug to pass. The addition of the second success criterion substantially reduced the risk of an inadequate, weakly efficacious drug proceeding to future development. The study was terminated at the interim analysis due to inadequate analgesic efficacy. A Bayesian approach using probabilistic statements enables clear understanding of success criteria, leading to informed decisions for study conduct. Incorporating an interim analysis can effectively reduce sample size, save resources, and minimize exposure of patients to an inadequate treatment.

Cannabinoid receptor 2 agonist attenuates pain related behavior in rats with chronic alcohol/high fat diet induced pancreatitis.

BACKGROUND: Chronic Pancreatitis (CP) is a complex and multifactorial syndrome. Many contributing factors result in development of dysfunctional pain in a significant number of patients. Drugs developed to treat a variety of pain states fall short of providing effective analgesia for patients with chronic pancreatitis, often providing minimal to partial pain relief over time with significant side effects. Recently, availability of selective pharmacological tools has enabled great advances in our knowledge of the role of the cannabinoid receptors in pathophysiology. In particular, cannabinoid receptor 2 (CB2) has emerged as an attractive target for management of chronic pain, as demonstrated in several studies with inflammatory and neuropathic preclinical pain models. In this study, the analgesic efficacy of a novel, highly selective CB2 receptor agonist, LY3038404 HCl, is investigated in a chronic pancreatitis pain model, induced with an alcohol/high fat (AHF) diet. RESULTS: Rats fed the AHF diet developed visceral pain-like behaviors detectable by week 3 and reached a maximum at week 5 that persists as long as the diet is maintained. Rats with AHF induced chronic pancreatitis were treated with LY3038404 HCl (10 mg/kg, orally, twice a day for 9 days). The treated animals demonstrated significantly alleviated pain related behaviors after 3 days of dosing, including increased paw withdrawal thresholds (PWT), prolonged abdominal withdrawal latencies (ABWL), and decreased nocifensive responses to noxious 44°C hotplate stimuli. Terminal histological analysis of pancreatic tissue sections from the AHF chronic pancreatitis animals demonstrated extensive injury, including a global pancreatic gland degeneration (cellular atrophy), vacuolization (fat deposition), and fibrosis. After the LY3038404 HCl treatment, pancreatic tissue was significantly protected from severe damage and fibrosis. LY3038404 HCl affected neither open field exploratory behaviors nor dark/light box preferences as measures of higher brain and motor functions. CONCLUSION: LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties without effects on higher brain function. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for visceral inflammation and pain management.

Gain and loss of function of P2X7 receptors: mechanisms, pharmacology and relevance to diabetic neuropathic pain.

BACKGROUND: Genetic causes of exaggerated or reduced pain sensitivity in humans are well known. Recently, single nucleotide polymorphisms (SNPs) in the gene P2RX7, coding for the ATP-gated ion channel P2X7, have been described that cause gain-of-function (GOF) and loss-of-function (LOF), respectively of this channel. Importantly, P2RX7 SNPs have been associated with more or less severe pain scores in patient suffering of post-mastectomy pain and osteoarthritis. RESULTS: The functional consequences of some P2RX7 SNPs (rs208294 (His155Tyr), rs1718119 (Ala348Thr) and rs3751143 (Glu496Ala)) were studied in recombinant cells in vitro. Our findings suggest a correlation between GOF and LOF of P2X7 and actual channel protein expression. Both channel and pore function for these mutant P2X7 receptors changed in parallel to protein levels. On the other hand, the mutant receptors did not differ in their sensitivity to known P2X7 agonists and antagonists. We further demonstrated that in patients with diabetic peripheral neuropathic pain (DPNP), the presence of the GOF SNPs rs208294 (His155Tyr) and rs1718119 (Ala348Thr) is associated, in females, with higher pain intensity scores. CONCLUSIONS: Our present results confirm the physiological relevance of some of the SNPs in the P2RX7 gene and show that the presence of these genetic variants correlates with pain sensitivity also in a diabetic neuropathic pain patient population.

Acupuncture-based modalities: novel alternative approaches in the treatment of gastrointestinal dysmotility in patients with systemic sclerosis.

BACKGROUND: The gastrointestinal (GI) dysmotility of systemic sclerosis (SSc, scleroderma) patients requires careful evaluation and intervention. The lack of effective prokinetic drugs motivate researchers to search for alternative treatments. OBJECTIVES: We present an overview of the pathophysiology of SSc GI dysmotility and the advances in its management, with particular focus on acupuncture-related modalities and innovative therapies. DATA SOURCES: Original research articles were identified based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline methodology. We have searched the MEDLINE database using Medical Subject Heading (MeSH) for all English and non-English articles with an English abstract from 2005 to October 2012. RESULTS: Only four original articles of various study designs were found studying Complementary and Alternative Medicine (CAM) therapies for SSc patients. Despite the small patient study numbers, CAM treatments, acupressure, and transcutaneous electroacupuncture, showed self-reported and physiologic evidence of improvement of GI functioning and/or symptoms in SSc patients. CONCLUSIONS: CAM therapies include experimental modalities with the potential to offer relief of symptoms from GI dysmotility. Larger studies are needed to investigate their optimal use in patient subsets to tailor therapies to patient needs.

Value of isolated IgA anti-ß2 -glycoprotein I positivity in the diagnosis of the antiphospholipid syndrome.

OBJECTIVE: To examine the prevalence of isolated IgA anti-ß2 -glycoprotein I (anti-ß2 GPI) positivity and the association of these antibodies, and a subgroup that bind specifically to domain IV/V of ß2 GPI, with clinical manifestations of the antiphospholipid syndrome (APS) in 3 patient groups and to evaluate the pathogenicity of IgA anti-ß2 GPI in a mouse model of thrombosis. METHODS: Patients with systemic lupus erythematosus (SLE) from a multiethnic, multicenter cohort (LUpus in MInorities, NAture versus nurture [LUMINA]) (n = 558), patients with SLE from the Hopkins Lupus Cohort (n = 215), and serum samples referred to the Antiphospholipid Standardization Laboratory (APLS) (n = 5,098) were evaluated. IgA anti-ß2 GPI titers and binding to domain IV/V of ß2 GPI were examined by enzyme-linked immunosorbent assay (ELISA). CD1 mice were inoculated with purified IgA anti-ß2 GPI antibodies, and surgical procedures and ELISAs were performed to evaluate thrombus development and tissue factor (TF) activity. RESULTS: A total of 198 patients were found to be positive for IgA anti-ß2 GPI isotype, and 57 patients were positive exclusively for IgA anti-ß2 GPI antibodies. Of these, 13 of 23 patients (56.5%) in the LUMINA cohort, 17 of 17 patients (100%) in the Hopkins cohort, and 10 of 17 patients (58.9%) referred to APLS had at least one APS-related clinical manifestation. Fifty-four percent of all the IgA anti-ß2 GPI-positive serum samples reacted with domain IV/V of anti-ß2 GPI, and 77% of those had clinical features of APS. Isolated IgA anti-ß2 GPI positivity was associated with an increased risk of arterial thrombosis (P < 0.001), venous thrombosis (P = 0.015), and all thrombosis (P < 0.001). The association between isolated IgA anti-ß2 GPI and arterial thrombosis (P = 0.0003) and all thrombosis (P = 0.0003) remained significant after adjusting for other risk factors for thrombosis. In vivo mouse studies demonstrated that IgA anti-ß2 GPI antibodies induced significantly larger thrombi and higher TF levels compared to controls. CONCLUSION: Isolated IgA anti-ß2 GPI-positive titers may identify additional patients with clinical features of APS. Testing for these antibodies when other antiphospholipid tests are negative and APS is suspected is recommended. IgA anti-ß2 GPI antibodies directed to domain IV/V of ß2 GPI represent an important subgroup of clinically relevant antiphospholipids.

Excitatory amino acids display compartmental disparity between plasma and synovial fluid in clinical arthropathies.

BACKGROUND: Previous studies have demonstrated elevated levels of excitatory amino acids (EAA) glutamate (Glu) and aspartate (Asp) in the synovial fluid (SF) of patients with active arthritis. The source of SF EAA concentrations are thought in large part to be secondary to passive diffusion from the plasma across synovial membranes and less so, reflective of local synovial pathology. OBJECTIVE: This descriptive report assesses the hypothesis that the SF EAA levels reflect inflammatory processes of the joint and are not dependent on plasma levels. METHODS: Simultaneously drawn plasma and SF samples were obtained from 14 recently deceased cadavers and 10 patients with active arthritis. Plasma and SF EAA and other amino acid (AA) levels were determined by HPLC. SF: Plasma compartment concentration ratios were calculated to assess if SF EAA levels were similar to plasma levels. RESULTS: In the cadavers with no antemortem arthritis, the mean SF: Plasma ratios for Glu and Asp were 4-5-fold lower than the mean ratios seen for 9 other AAs, showing specific discrepancies of EAA levels between plasma and synovial fluid. In 9 patients with active arthritis, the SF: Plasma concentration ratios were higher in samples derived from inflammatory arthropathies. CONCLUSIONS: Clinical samples demonstrated distinct, independent compartmental EAA concentrations between blood and joint compartments in support that local arthritic processes rather than plasma influence SF EAA concentrations. The SF EAA levels, whether from local cell production, local neurogenic sources, and/or transport-gradient mechanisms, parallel local pathology in the joint compartment and thus serve as surrogate biomarkers of local inflammatory processes.

Prolonged treatment with transcutaneous electrical nerve stimulation (TENS) modulates neuro-gastric motility and plasma levels of vasoactive intestinal peptide (VIP), motilin and interleukin-6 (IL-6) in systemic sclerosis.

PURPOSE: We assessed the effects of transcutaneous electrical nerve stimulation (TENS) on neurogastric functioning in scleroderma patients. METHODS: Seventeen SSc patients underwent 30 min TENS treatment >10Hz at GI acupuncture points PC6 and ST36, once (acute TENS) and then after two weeks of TENS sessions for 30 min twice daily (prolonged TENS). Data collected at Visits 1 and 2 included gastric myoelectrical activity (GMA) by surface electrogastrography (EGG), heart rate variability (HRV) by surface electrocardiography (EKG), GI specific symptoms and health related SF-36 questionnaires. Plasma VIP, motilin and IL-6 levels were determined. Statistical analyses were performed by Student's t-test, Spearman Rank and p-values <0.05 were considered significant. RESULTS: 1. Only after prolonged TENS, the percentages of normal slow waves and average slow wave coupling (especially channels 1, 2 reflecting gastric pacemaker and corpus regions) were significantly increased; 2. the percentage of normal slow waves was significantly correlated to sympathovagal balance; 3. Mean plasma VIP and motilin levels were significantly decreased after acute TENS, (vs. baseline), generally maintained in the prolonged TENS intervals. Compared to baseline, mean plasma IL-6 levels were significantly increased after acute TENS, but significantly decreased after prolonged TENS. 4. After prolonged TENS, the frequency of awakening due to abdominal pain and abdominal bloating were significantly and modestly decreased, respectively. CONCLUSIONS: In SSc patients, two weeks of daily TENS improved patient GMA scores, lowered plasma VIP, motilin and IL-6 levels and improved association between GMA and sympathovagal balance. This supports the therapeutic potential of prolonged TENS to enhance gastric myoelectrical functioning in SSc.

Measuring illness behavior in patients with systemic sclerosis.

OBJECTIVE: Illness behaviors (cognitive, affective, and behavioral reactions) among individuals with systemic sclerosis (SSc; scleroderma) are of clinical concern due to relationships between these behaviors and physical and mental quality of life, such as pain and symptoms of depression. Self-report measures with good psychometric properties can aid in the accurate assessment of illness behavior. The Illness Behavior Questionnaire (IBQ) was designed to measure abnormal illness behaviors; however, despite its longstanding use, there is disagreement regarding its subscales. The goal of the present study was to evaluate the validity of the IBQ in a cohort of patients with SSc. METHODS: Patients with SSc (n = 278) completed the IBQ at enrollment into the Genetics Versus Environment in Scleroderma Outcome Study. Structural validity of previously derived factor solutions was investigated using confirmatory factor analysis. Exploratory factor analysis was utilized to derive SSc-specific subscales. RESULTS: None of the previously derived structural models were supported for SSc patients. Exploratory factor analysis supported an SSc-specific factor structure with 5 subscales. Validity analyses suggested that the subscales were generally independent of disease severity, but were correlated with other health outcomes (i.e., fatigue, pain, disability, social support, and mental health). CONCLUSION: The proposed subscales are recommended for use in SSc, and can be utilized to capture illness behavior that may be of clinical concern.

Predictors of fatigue severity in early systemic sclerosis: a prospective longitudinal study of the GENISOS cohort.

OBJECTIVES: Longitudinal studies examining the baseline predictors of fatigue in SSc have not been reported. Our objectives were to examine the course of fatigue severity over time and to identify baseline clinical, demographic, and psychosocial predictors of sequentially obtained fatigue scores in early SSc. We also examined baseline predictors of change in fatigue severity over time. METHODS: We analyzed 1090 longitudinal Fatigue Severity Scale (FSS) scores belonging to 256 patients who were enrolled in the Genetics versus Environment in Scleroderma Outcomes Study (GENISOS). Predictive significance of baseline variables for sequentially obtained FSS scores was examined with generalized linear mixed models. Predictors of change in FSS over time were examined by adding an interaction term between the baseline variable and time-in-study to the model. RESULTS: The patients' mean age was 48.6 years, 47% were Caucasians, and 59% had diffuse cutaneous involvement. The mean disease duration at enrollment was 2.5 years. The FSS was obtained at enrollment and follow-up visits (mean follow-up time = 3.8 years). Average baseline FSS score was 4.7(±0.96). The FSS was relatively stable and did not show a consistent trend for change over time (p = 0.221). In a multivariable model of objective clinical variables, higher Medsger Gastrointestinal (p = 0.006) and Joint (p = 0.024) Severity Indices, and anti-U1-RNP antibodies (p = 0.024) were independent predictors of higher FSS. In the final model, ineffective coping skills captured by higher Illness Behavior Questionnaire scores (p<0.001), higher self-reported pain (p = 0.006), and higher Medsger Gastrointestinal Severity Index (p = 0.009) at enrollment were independent predictors of higher longitudinal FSS scores. Baseline DLco % predicted was the only independent variable that significantly predicted a change in FSS scores over time (p = 0.013), with lower DLco levels predicting an increase in FSS over time. CONCLUSIONS: This study identified potentially modifiable clinical and psychological factors that predict longitudinal fatigue severity in early SSc.

Anorectal motility and sensation abnormalities and its correlation with anorectal symptoms in patients with systemic sclerosis: a preliminary study.

Gastrointestinal (GI) hypomotility and symptoms are common in Scleroderma (SSc) patients yet so far uncorrelated. Eight SSc patients and matched controls were queried about their GI dysmotility symptoms and quality of life (QoL) and underwent anorectal motility and sensory tests. Specific scoring systems were developed for anorectal symptoms and anorectal dysmotility. We found that (1) the SSc patients showed low QoL and marked overall GI symptoms. The most common anorectal symptom was incomplete bowel movement (50%). (2) Compared to normal controls, SSc patients showed impaired anorectal pressures, sensations, and rectal compliance (P ≤ .01 for each). (3) The anorectal motility/sensation abnormality score was robustly correlated with the total anorectal symptom score (r(s) = .78, P = .02). In conclusion, scleroderma patients have impaired anorectal motor and sensory functions, and the abnormality score of these anorectal functions is correlated with the total anorectal symptoms score. These scoring systems may assist clinicians in predicting dysmotility based on patient symptoms.

Anti-fibrillarin antibody in African American patients with systemic sclerosis: immunogenetics, clinical features, and survival analysis.

OBJECTIVE: Anti-U3-RNP, or anti-fibrillarin antibodies (AFA), are detected more frequently among African American (AA) patients with systemic sclerosis (SSc) compared to other ethnic groups and are associated with distinct clinical features. We examined the immunogenetic, clinical, and survival correlates of AFA in a large group of AA patients with SSc. METHODS: Overall, 278 AA patients with SSc and 328 unaffected AA controls were enrolled from 3 North American cohorts. Clinical features, autoantibody profile, and HLA class II genotyping were determined. To compare clinical manifestations, relevant clinical features were adjusted for disease duration. Cox proportional hazards regression was used to determine the effect of AFA on survival. RESULTS: Fifty (18.5%) AA patients had AFA. After Bonferroni correction, HLA-DRB1*08:04 was associated with AFA, compared to unaffected AA controls (OR 11.5, p < 0.0001) and AFA-negative SSc patients (OR 5.2, p = 0.0002). AFA-positive AA patients had younger age of disease onset, higher frequency of digital ulcers, diarrhea, pericarditis, higher Medsger perivascular and lower Medsger lung severity indices (p = 0.004, p = 0.014, p = 0.019, p = 0.092, p = 0.006, and p = 0.016, respectively). After adjustment for age at enrollment, AFA-positive patients did not have different survival compared to patients without AFA (p = 0.493). CONCLUSION: Our findings demonstrate strong association between AFA and HLA-DRB1*08:04 allele in AA patients with SSc. AA SSc patients with AFA had younger age of onset, higher frequency of digital ulcers, pericarditis and severe lower gastrointestinal involvement, but less severe lung involvement compared to AA patients without AFA. Presence of AFA did not change survival.

Determinants of work disability in patients with systemic sclerosis: a longitudinal study of the GENISOS cohort.

OBJECTIVES: To determine the prevalence, correlates, and predictors of work disability (WD) in the Genetics versus ENvironment In Scleroderma Outcome Study (GENISOS). We hypothesized that WD in systemic sclerosis (SSc) is a function of demographic, clinical, and psychosocial factors. METHODS: Patients enrolled in the GENISOS cohort were subdivided in 3 groups: work disabled, working, and retired or homemakers. The latter group (n = 29) was excluded from further analysis. We used logistic regression analysis with a forward hierarchical variable selection strategy to investigate the independent correlates of WD at enrollment. Cox regression proportional Hazard's model with a similar variable selection strategy was utilized to determine the predictors of WD in those working at enrollment. RESULTS: Overall, 284 patients with a mean age of 48.7 years and disease duration of 2.5 (±1.6) years were enrolled into the GENISOS cohort, consisting of 83.5% female, 46.8% white, 28.9% Hispanic, and 20.4% African American. Patients were longitudinally followed in 1438 study visits. At enrollment, 124 patients (43.7%) were work disabled, whereas 131 (46.1%) were working. Lower level of education (P < 0.001), higher Medsger Lung Severity Index (P = 0.012), higher Fatigue Severity Score (P = 0.008), and less social support (P < 0.001) correlated independently with WD. Of those working at baseline, 35 (26.7%) eventually developed WD. Non-white ethnicity (P = 0.038), lower DLCO % predicted value (P = 0.038), and higher Fatigue Severity Score (P = 0.009) at enrollment independently predicted WD on follow-up visits. CONCLUSIONS: WD is a major problem among SSc patients and its prevalence is substantially higher than other rheumatic conditions. Demographic, clinical, and psychosocial factors correlate with WD cross-sectionally and predict WD longitudinally in these patients.

Impaired postprandial releases/syntheses of ghrelin and PYY(3-36) and blunted responses to exogenous ghrelin and PYY(3-36) in a rodent model of diet-induced obesity.

BACKGROUND AND AIM: This study investigated the effects of peripheral administration of ghrelin and PYY(3-36) on food intake and plasma and tissue fasting and postprandial ghrelin and PYY(3-36) levels in normal-weight (NW) and diet-induced-obese (DIO) rats. METHODS: In experiment one, NW and DIO rats received a single intraperitoneal injection of saline, PYY(3-36) or ghrelin; food intake was measured for 4 h. In experiment two, total plasma ghrelin and PYY(3-36), gastric fundus ghrelin, and ascending colon PYY(3-36) were measured either after a 20-h fast or 2 h after refeeding in NW and DIO rats by radioimmunoassay. RESULTS: Compared to the NW rats, findings in the DIO rats revealed: (i) a reduced sensitivity to both the anorectic effect of exogenous PYY(3-36) and the orexigenic effect of exogenous ghrelin; (ii) the postprandial plasma ghrelin levels were significantly higher; and (iii) refeeding decreased endogenous plasma ghrelin levels by 53% in the NW rats and 39% in DIO rats. Refeeding increased the plasma PYY(3-36) level by 58% in the NW rats versus 9% in the DIO rats (P=0.003). CONCLUSIONS: Compared with regular rats, DIO rats exhibit blunted responses in food intake to exogenous ghrelin and PYY(3-36). Although endogenous ghrelin and PYY(3-36) in DIO rats are not altered in the fasting state, their responses to food ingestion are blunted in comparison with regular rats.

Predictors of interstitial lung disease in early systemic sclerosis: a prospective longitudinal study of the GENISOS cohort.

INTRODUCTION: The objective of the present study was to examine the association of baseline demographic and clinical characteristics with sequentially obtained measurements of forced vital capacity (FVC), expressed as a percentage of the predicted value, and to identify predictors of the decline rate in FVC over time in the Genetics versus Environment in Scleroderma Outcome Study (GENISOS). METHODS: To date, 266 patients have been enrolled in GENISOS, a prospective, observational cohort of patients with early systemic sclerosis. In addition to pulmonary function tests (PFTs), clinical and laboratory data were obtained from each patient. We analyzed 926 FVC measurements utilizing generalized linear mixed models. The predictive significance of baseline variables for the decline rate in FVC was investigated by the interaction term between the variable and the follow-up time within the first 3 years after enrollment as well as throughout the entire follow-up time. RESULTS: The cohort consisted of 125 white, 54 African American, and 77 Hispanic patients with average disease duration of 2.5 years at enrollment. The mean follow-up time was 3.8 years, ranging up to 11.4 years. A number of baseline variables, including antibody status, African American ethnicity, disease type, baseline PFT values, modified Rodnan Skin Score, fibrosis on chest radiograph, and lung and skin subscores of the Severity Index, were associated with serially measured FVC levels. However, only the presence of anti-topoisomerase I antibodies (ATA) was associated with lower FVC levels (P < 0.001) as well as accelerated decline rate in FVC within the first 3 years of follow-up (P = 0.02). None of the baseline variables predicted the rate of decline in FVC on long-term follow-up. Patients with rapidly progressive ILD, however, were under-represented in the long-term follow-up group because the accelerated rate of decline in FVC was associated with poor survival (P = 0.001). CONCLUSIONS: Presence of ATA was the only baseline variable associated with differential FVC levels, predicting the rate of decline in FVC within the first 3 years of follow-up. The association of faster decline in FVC with poor survival further emphasizes the need for identification of predictive biomarkers by collection of genetic information and serial blood samples in cohort studies.

Impact of central and peripheral TRPV1 and ROS levels on proinflammatory mediators and nociceptive behavior.

BACKGROUND: Transient receptor potential vanilloid 1 (TRPV1) channels are important membrane sensors on peripheral nerve endings and on supportive non-neuronal synoviocytes in the knee joint. TRPV 1 ion channels respond with activation of calcium and sodium fluxes to pH, thermal, chemical, osmotic, mechanical and other stimuli abundant in inflamed joints. In the present study, the kaolin/carrageenan (k/c) induced knee joint arthritis model in rats, as well as primary and clonal human synoviocyte cultures were used to understand the reciprocal interactions between reactive nitroxidative species (ROS) and functional TRPV1 channels. ROS generation was monitored with ROS sensitive dyes using live cell imaging in vitro and in spinal tissue histology, as well as with measurement of ROS metabolites in culture media using HPLC. RESULTS: Functional responses in the experimental arthritis model, including increased nociceptive responses (thermal and mechanical hyperalgesia and allodynia), knee joint temperature reflecting local blood flow, and spinal cord ROS elevations were reduced by the ROS scavenger PBN after intraperitoneal pretreatment. Increases in TRPV1 and ROS, generated by synoviocytes in vitro, were reciprocally blocked by TRPV1 antagonists and the ROS scavenger. Further evidence is presented that synoviocyte responses to ROS and TRPV1 activation include increases in TNFalpha and COX-2, both measured as an indicator of the inflammation in vitro. CONCLUSIONS: The results demonstrate that contributions of ROS to pronociceptive responses and neurogenic inflammation are mediated both centrally and peripherally. Responses are mediated by TRPV1 locally in the knee joint by synoviocytes, as well as by ROS-induced sensitization in the spinal cord. These findings and those of others reported in the literature indicate reciprocal interactions between TRPV1 and ROS play critical roles in the pathological and nociceptive responses active during arthritic inflammation.

Plasma endogenous enkephalin levels in early systemic sclerosis: clinical and laboratory associations.

OBJECTIVE: Met- and leu-enkephalins are endogenous opioid neuropeptides with potent analgesic, vasoactive, immunomodulatory and anti-apoptotic properties. We hypothesised that clinical or immunological variables of early systemic sclerosis (SSc) might be correlated to plasma enkephalin levels. METHODS: Plasma samples were collected at study entry of the Genetics versus Environment in Scleroderma Outcomes Study (GENISOS) cohort (early SSc, n=116). Plasma met-enkephalin and leu-enkephalin levels (microg/ml) were measured by high performance liquid chromatography (HPLC) and correlated to clinical and laboratory parameters in the GENISOS database. Statistical analyses were performed by nonparametric Wilcoxon rank sum tests and Pearson correlation coefficients. RESULTS: Significantly lower plasma met-enkephalin levels were associated with anti-topoisomerase-I seropositivity (6+8.3 vs. 14.9+22.8 microg/ml, p=0.02). Plasma leu-enkephalin levels were significantly higher in SSc patients with digital pulp loss (95.6+130 vs. 64.9+101 microg/ml, p=0.02). Lower mean plasma met-enkephalin levels and inversely higher leu-enkephalin levels were noted in SSc patients with Raynaud's phenomena (p=NS). CONCLUSION: The associations of plasma enkephalin levels to immunologic or clinical pathologies may underscore their vasogenic or fibrogenic significance and potential as therapeutic targets in early SSc.