Epigenetic activation and memory at a TGFB2 enhancer in systemic sclerosis

In systemic sclerosis (SSc), previously healthy adults develop an inflammatory prodrome with subsequent progressive fibrosis of the skin and viscera. SSc has a weak signature for genetic contribution, and there are few pathogenic insights or targeted treatments for this condition. Here, chromatin accessibility and transcriptome profiling coupled with targeted epigenetic editing revealed constitutive activation of a previously unannotated transforming growth factor-β2 (TGFB2) enhancer maintained through epigenetic memory in SSc. The resulting autocrine TGFβ2 signaling enforced a profibrotic synthetic state in ex vivo fibroblasts from patients with SSc. Inhibition of NF-κB or BRD4 achieved sustained inhibition of TGFB2 enhancer activity, mitigated profibrotic gene expression, and reversed dermal fibrosis in patient skin explants. These findings suggest a potential epigenetic mechanism of fibrosis in SSc and inform a regulatory mechanism of TGFB2, a major profibrotic cytokine.

Brief Report: Whole-Exome Sequencing to Identify Rare Variants and Gene Networks That Increase Susceptibility to Scleroderma in African Americans

OBJECTIVE

Whole-exome sequencing (WES) studies in systemic sclerosis (SSc) patients of European American (EA) ancestry have identified variants in the ATP8B4 gene and enrichment of variants in genes in the extracellular matrix (ECM)-related pathway that increase SSc susceptibility. This study was undertaken to evaluate the association of the ATP8B4 gene and the ECM-related pathway with SSc in a cohort of African American (AA) patients.

METHODS

SSc patients of AA ancestry were enrolled from 23 academic centers across the US under the Genome Research in African American Scleroderma Patients consortium. Unrelated AA individuals without serologic evidence of autoimmunity who were enrolled in the Howard University Family Study were used as unaffected controls. Functional variants in genes reported in the 2 WES studies in EA patients with SSc were selected for gene association testing using the optimized sequence kernel association test (SKAT-O) and pathway analysis by Ingenuity Pathway Analysis in 379 patients and 411 controls.

RESULTS

Principal components analysis demonstrated that the patients and controls had similar ancestral backgrounds, with roughly equal proportions of mean European admixture. Using SKAT-O, we examined the association of individual genes that were previously reported in EA patients and none remained significant, including ATP8B4 (P = 0.98). However, we confirmed the previously reported association of the ECM-related pathway with enrichment of variants within the COL13A1, COL18A1, COL22A1, COL4A3, COL4A4, COL5A2, PROK1, and SERPINE1 genes (corrected P = 1.95 × 10-4 ).

CONCLUSION

In the largest genetic study in AA patients with SSc to date, our findings corroborate the role of functional variants that aggregate in a fibrotic pathway and increase SSc susceptibility.

Determining the Risk Factors and Clinical Features Associated With Severe Gastrointestinal Dysmotility in Systemic Sclerosis

OBJECTIVE

A subset of patients with systemic sclerosis (SSc) develop severe gastrointestinal (GI) dysmotility. We sought to determine predictors of severe SSc GI dysmotility and to identify distinct features associated with this phenotype.

METHODS

Patients with SSc who required supplemental nutrition (enteral or parenteral tube feeding) were compared to SSc patients with mild GI symptoms in a cross-sectional analysis. The association between severe GI dysmotility and clinical and serologic features was examined using logistic regression. Baseline data were examined to determine predictors of developing severe GI dysfunction using Cox regression.

RESULTS

SSc patients with severe GI dysmotility (n = 66) were more likely than those patients with mild GI symptoms (n = 1,736) to be male (odds ratio [OR] 2.47 [95% confidence interval (95% CI) 1.34-4.56]; P = 0.004), and to have myopathy (OR 5.53 [95% CI 2.82-10.82]; P < 0.001), and sicca symptoms (OR 2.40 [95% CI 1.30-4.42]; P = 0.005), even after adjustment for potential confounders. Baseline features that were associated with the future development of severe GI dysfunction included male sex (hazard ratio [HR] 2.99 [95% CI 1.53-5.84]; P = 0.001) and myopathy (HR 5.08 [95% CI 2.21-11.67]; P < 0.001).

CONCLUSION

Distinct clinical features are present in SSc patients who are at risk of developing severe GI dysmotility. This finding is not only important clinically but also suggests that a unique pathologic process is at work in these patients.

Pharmacotherapy Options in the Management of Raynaud's Phenomenon

Purpose of review

Multiple classes of medications have been studied for the treatment of Raynaud's phenomenon (RP) with or without digital ischemia. The goal of this review is to discuss the outcomes of recent studies and to report on our approach to the management of RP in light of the available evidence.

Recent findings

Comparing treatments for RP remains a challenge as efficacy endpoint vary widely among trials. While calcium channel blockers are used first-line in the pharmacologic management of RP, phosphodiesterase 5 inhibitors have also been shown to be beneficial in reducing symptoms. In the setting of digital ischemia, administration of intravenous prostanoids is the standard of care. Bosentan has shown benefit in the prevention of future ulcers in patients with scleroderma. Botulinum toxin therapy was ineffective in a clinical trial involving scleroderma patients; more controlled studies are needed in other subsets of patients. Digital sympathectomy may be beneficial in cases of critical digital ischemia, though recurrence of symptoms is common.

Summary

Comparative effectiveness studies are needed to determine which therapeutic interventions are most beneficial in patients with RP. Based on the available evidence, we start with CCBs and add a phosphodiesterase inhibitor if symptoms are not controlled, or intravenous prostacyclin in the setting of severe critical digital ischemia. We may additionally add an endothelial receptor antagonist in cases of recurrent digital ulcers. A surgical sympathectomy may be used in refractory cases of digital ischemia. A digital block may also be a less invasive, but temporary, intervention allowing for titration of medical therapy.

Right Ventricular Myofilament Functional Differences in Humans With Systemic Sclerosis-Associated Versus Idiopathic Pulmonary Arterial Hypertension

BACKGROUND

Patients with systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) have a far worse prognosis than those with idiopathic PAH (IPAH). In the intact heart, SSc-PAH exhibits depressed rest and reserve right ventricular (RV) contractility compared with IPAH. We tested whether this disparity involves underlying differences in myofilament function.

METHODS

Cardiac myocytes were isolated from RV septal endomyocardial biopsies from patients with SSc-PAH, IPAH, or SSc with exertional dyspnea but no resting PAH (SSc-d); control RV septal tissue was obtained from nondiseased donor hearts (6-7 per group). Isolated myocyte passive length-tension and developed tension-calcium relationships were determined and correlated with in vivo RV function and reserve. RV septal fibrosis was also examined.

RESULTS

Myocyte passive stiffness from length-tension relations was similarly increased in IPAH and SSc-PAH compared with control, although SSc-PAH biopsies had more interstitial fibrosis. More striking disparities were found between active force-calcium relations. Compared with controls, maximal calcium-activated force (Fmax) was 28% higher in IPAH but 37% lower in SSc-PAH. Fmax in SSc-d was intermediate between control and SSc-PAH. The calcium concentration required for half-maximal force (EC50) was similar between control, IPAH, and SSc-d but lower in SSc-PAH. This disparity disappeared in myocytes incubated with the active catalytic subunit of protein kinase A. Myocyte Fmax directly correlated with in vivo RV contractility assessed by end-systolic elastance (R2 =0.46, P=0.002) and change in end-systolic elastance with exercise (R2 =0.49, P=0.008) and was inversely related with exercise-induced chamber dilation (R2 =0.63, P<0.002), which also was a marker of depressed contractile reserve.

CONCLUSIONS

A primary defect in human SSc-PAH resides in depressed sarcomere function, whereas this is enhanced in IPAH. These disparities correlate with in vivo RV contractility and contractile reserve and are consistent with worse clinical outcomes in SSc-PAH. The existence of sarcomere disease before the development of resting PAH in patients with SSc-d suggests that earlier identification and intervention may prove useful.

Vascular complications in systemic sclerosis: a prospective cohort study

Two major complications in scleroderma patients that cause substantial morbidity and mortality are ischemic digital lesions (DL) and pulmonary hypertension (PH). The clinician's ability to predict which patients will develop these complications is imperfect. We conducted a prospective observational cohort study of 300 patients with scleroderma who were followed for at least a 5-year period. At baseline, patients lacked evidence of PH and were without a current DL. At each 6-month visit, the patient was examined for signs/symptoms of PH and/or a DL. The primary outcomes were (1) PH defined as a mean pulmonary artery pressure ≥ 25 mmHg by right heart catheterization and (2) ≥ 1 DL defined as new onset of severe vascular compromise. Thirty patients (10%) developed PH (11 group 1/PAH, 4 group II, 15 group III) and 69 developed DL. The average time from enrollment until diagnosis of PH was 3.2 ± 2 years. In multivariable analyses, patients who developed PH were more likely to have diffuse disease (HR 3.2, p = 0.004), a forced vital capacity (FVC)/diffusing capacity of the lungs for carbon monoxide (DLCO) ratio > 1.6 (HR 1.7, p = 0.008), and elevated RVSP (HR = 1.07, p = 0.007). Patients who developed PAH were more likely to have a FVC/DLCO ratio > 1.6 (HR = 5.8, p = 0.014), and patients who developed group III PH were less likely to have an elevated FVC (HR = 0.92, p = 0.001). Patients were more likely to develop a DL if they had a history of prior DL (HR = 7.0, p < 0.001), or were men (HR = 2.3, p = 0.007). In a prevalent cohort of scleroderma patients, individuals who develop PH or DL have simple to measure clinical features that can predict these complications years before they occur.

Autoantibodies and scleroderma phenotype define subgroups at high-risk and low-risk for cancer

OBJECTIVES

Recent studies demonstrate autoantibodies are powerful tools to interrogate molecular events linking cancer and the development of autoimmunity in scleroderma. Investigating cancer risk in these biologically relevant subsets may provide an opportunity to develop personalised cancer screening guidelines. In this study, we examined cancer risk in distinct serologic and phenotypic scleroderma subsets and compared estimates with the general population.

METHODS

Patients in the Johns Hopkins Scleroderma Center observational cohort were studied. Overall and site-specific cancer incidence was calculated in distinct autoantibody and scleroderma phenotypic subsets, and compared with the Surveillance, Epidemiology and End Results registry, a representative sample of the US population.

RESULTS

2383 patients with scleroderma contributing 37 686 person-years were studied. 205 patients (8.6%) had a diagnosis of cancer. Within 3 years of scleroderma onset, cancer risk was increased in patients with RNA polymerase III autoantibodies (antipol; standardised incidence ratio (SIR) 2.84, 95% CI 1.89 to 4.10) and those lacking centromere, topoisomerase-1 and pol antibodies (SIR 1.83, 95% CI 1.10 to 2.86). Among antipol-positive patients, cancer-specific risk may vary by scleroderma subtype; those with diffuse scleroderma had an increased breast cancer risk, whereas those with limited scleroderma had high lung cancer risk. In contrast, patients with anticentromere antibodies had a lower risk of cancer during follow-up (SIR 0.59, 95% CI 0.44 to 0.76).

CONCLUSIONS

Autoantibody specificity and disease subtype are biologically meaningful filters that may inform cancer risk stratification in patients with scleroderma. Future research testing the value of targeted cancer screening strategies in patients with scleroderma is needed.

Clinical and serological features of systemic sclerosis in a multicenter African American cohort: Analysis of the genome research in African American scleroderma patients clinical database

Racial differences exist in the severity of systemic sclerosis (SSc). To enhance our knowledge about SSc in African Americans, we established a comprehensive clinical database from the largest multicenter cohort of African American SSc patients assembled to date (the Genome Research in African American Scleroderma Patients (GRASP) cohort).African American SSc patients were enrolled retrospectively and prospectively over a 30-year period (1987-2016), from 18 academic centers throughout the United States. The cross-sectional prevalence of sociodemographic, clinical, and serological features was evaluated. Factors associated with clinically significant manifestations of SSc were assessed using multivariate logistic regression analyses.The study population included a total of 1009 African American SSc patients, comprised of 84% women. In total, 945 (94%) patients met the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc, with the remaining 64 (6%) meeting the 1980 ACR or CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) criteria. While 43% were actively employed, 33% required disability support. The majority (57%) had the more severe diffuse subtype and a young age at symptom onset (39.1 ± 13.7 years), in marked contrast to that reported in cohorts of predominantly European ancestry. Also, 1 in 10 patients had a severe Medsger cardiac score of 4. Pulmonary fibrosis evident on computed tomography (CT) chest was present in 43% of patients and was significantly associated with anti-topoisomerase I positivity. 38% of patients with CT evidence of pulmonary fibrosis had a severe restrictive ventilator defect, forced vital capacity (FVC) ≤50% predicted. A significant association was noted between longer disease duration and higher odds of pulmonary hypertension, telangiectasia, and calcinosis. The prevalence of potentially fatal scleroderma renal crisis was 7%, 3.5 times higher than the 2% prevalence reported in the European League Against Rheumatism Scleroderma Trials and Research (EUSTAR) cohort.Our study emphasizes the unique and severe disease burden of SSc in African Americans compared to those of European ancestry.

Association of Fibrosing Myopathy in Systemic Sclerosis and Higher Mortality

OBJECTIVE

To determine if a unique subtype of scleroderma muscle disease exists by comparing the clinical features of systemic sclerosis (SSc; scleroderma) patients with predominant fibrosis on muscle biopsy to those with inflammatory muscle histopathology.

METHODS

This retrospective, cross-sectional study included SSc patients with muscle weakness and an available muscle biopsy. Biopsies with fibrosis but without inflammation/necrosis were designated as "fibrosing myopathy," and those with inflammation and/or necrosis were assigned a category of "inflammatory myopathy." Clinical data, including features of SSc, serum creatine kinase (CK) levels, electromyography, autoantibody profile, and survival, were compared between the 2 groups.

RESULTS

The study population consisted of 37 weak SSc patients, 8 with fibrosing myopathy and 29 with inflammatory myopathy. Compared to those with inflammatory myopathy, patients with fibrosing myopathy were more likely to have diffuse SSc skin subtype (87% versus 62%; P = 0.18), African American race (62.5% versus 37.9%; P = 0.20), and a lower mean ± SD forced vital capacity (55.5 ± 31.9 versus 66.4 ± 17.6; P = 0.23). They also had lower mean ± SD CK values (516 ± 391 versus 2,477 ± 3,511 IU/liter; P = 0.007) and lower aldolase values (13.8 ± 4.7 versus 27.3 ± 4.7; P = 0.01). Patients with fibrosing myopathy had a significantly higher mortality (5 of 8 [62.5%] versus 4 of 29 [14.3%]; P = 0.005).

CONCLUSION

Fibrosing myopathy is a unique histologic subtype of muscle disease among weak patients with SSc and is associated with significantly worse mortality compared to those with inflammation and/or necrosis on muscle biopsy.

Brief Report: Anti-RNPC-3 Antibodies As a Marker of Cancer-Associated Scleroderma

OBJECTIVE

Prior studies have demonstrated an increased risk of cancer-associated scleroderma in patients with anti-RNA polymerase III (anti-RNAP III) autoantibodies as well as in patients who are triple-negative for anticentromere (anti-CENP), anti-topoisomerase I (anti-topo I), and anti-RNAP III (also known as anti-POL) autoantibodies (referred to as CTP negative). In a recent study of 16 CTP-negative scleroderma patients with coincident cancer, 25% of the patients were found to have autoantibodies to RNPC-3, a member of the minor spliceosome complex. This investigation was undertaken to validate the relationship between anti-RNPC-3 antibodies and cancer and examine the associated clinical phenotype in a large sample of scleroderma patients.

METHODS

Scleroderma patients with cancer were assayed for anti-CENP, anti-topo I, anti-RNAP III, and anti-RNPC-3 autoantibodies. Disease characteristics and the cancer-scleroderma interval were compared across autoantibody groups. The relationship between autoantibody status and cancer-associated scleroderma was assessed by logistic regression.

RESULTS

Of 318 patients with scleroderma and cancer, 70 (22.0%) were positive for anti-RNAP III, 54 (17.0%) were positive for anti-topo I, and 96 (30.2%) were positive for anti-CENP. Twelve patients (3.8% of the overall group or 12.2% of CTP-negative patients) were positive for anti-RNPC-3. Patients with anti-RNPC-3 had a short cancer-scleroderma interval (median 0.9 years). Relative to patients with anti-CENP, patients with anti-RNPC-3 and those with anti-RNAP III had a >4-fold increased risk of cancer within 2 years of scleroderma onset (for anti-RNPC-3-positive patients, odds ratio [OR] 4.3, 95% confidence interval [95% CI] 1.10-16.9 [P = 0.037]; for anti-RNAP III-positive patients, OR 4.49, 95% CI 1.98-10.2 [P < 0.001]). Patients with anti-RNPC-3 had severe restrictive lung disease, gastrointestinal disease, Raynaud's phenomenon, and myopathy.

CONCLUSION

Anti-RNPC-3 autoantibodies, similar to anti-RNAP III autoantibodies, are associated with an increased risk of cancer at the onset of scleroderma. These data suggest the possibility of cancer-induced autoimmunity in this subset of patients with scleroderma.

Symptomatic and Electrodiagnostic Features of Peripheral Neuropathy in Scleroderma

OBJECTIVE

To determine the prevalence of peripheral neuropathy in scleroderma.

METHODS

The prevalence of length-dependent peripheral neuropathy was rigorously assessed using signs and symptoms of neuropathy derived from the Total Neuropathy Score (TNS), and standardized nerve conduction study (NCS). All subjects underwent TNS and NCS. Those who were symptomatic or had NCS evidence of peripheral neuropathy underwent laboratory evaluation for secondary causes of neuropathy.

RESULTS

A total of 130 subjects were approached for participation and 60 enrolled. Of the 60 subjects, 50 (83.3%) were female and 37 (61.7%) were of the limited cutaneous subtype. The mean ± SD age was 55 ± 11.1 years, and mean ± SD disease duration was 15.3 ± 10.1 years. A total of 17 of 60 (28%) had evidence of a peripheral neuropathy as defined by the presence of neuropathic symptoms on the TNS (12 of 60) and/or electrophysiologic evidence of neuropathy (5 subjects with neuropathic symptoms and 5 without neuropathic symptoms). Subjects with neuropathy were more likely to be male (60% versus 40%; P = 0.02), African American (41% versus 4.6%; P = 0.001), have diabetes mellitus (17.7% versus 0%; P = 0.02), have limited cutaneous scleroderma (82.3% versus 53.5%; P = 0.04), and have anti-U1 RNP antibodies (23.5% versus 0%; P = 0.009) than those without neuropathy. A potential nonscleroderma etiology for the peripheral neuropathy such as diabetes mellitus was found in 82.3% (14 of 17) of subjects with neuropathy.

CONCLUSION

While symptoms or objective evidence of peripheral neuropathy are common among patients with scleroderma, the cause may often be attributed to comorbid nonscleroderma-related conditions.

Validation of the Self-Efficacy for Managing Chronic Disease Scale: A Scleroderma Patient-Centered Intervention Network Cohort Study

OBJECTIVE

Self-management programs for patients with chronic illnesses, including rheumatic diseases, seek to enhance self-efficacy for performing health management behaviors. No measure of self-efficacy has been validated for patients with systemic sclerosis (SSc; scleroderma). The objective of this study was to assess the validity and internal consistency reliability of the Self-Efficacy for Managing Chronic Disease (SEMCD) scale in SSc.

METHODS

English-speaking SSc patients enrolled in the Scleroderma Patient-centered Intervention Network Cohort who completed the SEMCD scale at their baseline assessment between March 2014 and June 2015 were included. Patients were enrolled from 21 sites in Canada, the US, and the UK. Confirmatory factor analysis (CFA) was used to evaluate the factor structure of the SEMCD scale. Cronbach's alpha was calculated to assess internal consistency reliability. Hypotheses on the direction and magnitude of Pearson's correlations with psychological and physical outcome measures were formulated and tested to examine convergent validity.

RESULTS

A total of 553 patients were included. CFA supported the single-factor structure of the SEMCD scale (Tucker Lewis Index = 0.99, comparative fit index = 0.99, root mean square error of approximation = 0.10). Internal consistency was high (α = 0.93), and correlations with measures of psychological and physical functioning were moderate to large (|r| = 0.48-0.67, P < 0.001), confirming study hypotheses.

CONCLUSION

Scores from the SEMCD scale are valid for measuring self-efficacy in patients with SSc, and results support using the scale as an outcome measure to evaluate the effectiveness of self-management programs in SSc.

Development and Validation of the Body Concealment Scale for Scleroderma

OBJECTIVE

Body concealment is a component of social avoidance among people with visible differences from disfiguring conditions, including systemic sclerosis (SSc). The study objective was to develop a measure of body concealment related to avoidance behaviors in SSc.

METHODS

Initial items for the Body Concealment Scale for Scleroderma (BCSS) were selected using item analysis in a development sample of 93 American SSc patients. The factor structure of the BCSS was evaluated in 742 Canadian patients with single-factor, 2-factor, and bifactor confirmatory factor analysis models. Convergent and divergent validity were assessed by comparing the BCSS total score with the Brief-Satisfaction with Appearance Scale (Brief-SWAP) and measures of depressive symptoms and pain.

RESULTS

A 2-factor model (Comparative Fit Index [CFI] 0.99, Tucker-Lewis Index [TLI] 0.98, Root Mean Square Error of Approximation [RMSEA] 0.08) fit substantially better than a 1-factor model (CFI 0.95, TLI 0.94, RMSEA 0.15) for the 9-item BCSS, but the Concealment with Clothing and Concealment of Hands factors were highly correlated (α = 0.79). The bifactor model (CFI 0.99, TLI 0.99, RMSEA 0.08) also fit well. In the bifactor model, the omega coefficient was high for the general factor (ω = 0.80), but low for the Concealment with Clothing (ω = 0.01) and Concealment of Hands (ω = 0.33) factors. The BCSS total score correlated more strongly with the Brief-SWAP Social Discomfort (r = 0.59) and Dissatisfaction with Appearance (r = 0.53) subscales than with measures of depressive symptoms and pain.

CONCLUSION

The BCSS sum score is a valid indicator of body concealment in SSc that extends the concepts of body concealment and avoidance beyond the realms of body shape and weight to concerns of individuals with visible differences from SSc.

Anti-Interferon-Inducible Protein 16 Antibodies Associate With Digital Gangrene in Patients With Scleroderma

OBJECTIVE

To examine the association between anti-interferon-inducible protein 16 (anti-IFI-16) antibodies and clinical features of scleroderma.

METHODS

Sera from a discovery sample of 94 patients with scleroderma and 47 healthy controls were assayed for anti-IFI-16 antibodies by enzyme-linked immunosorbent assay, and associations were examined using regression analyses. Since anti-IFI-16 autoantibodies were found to be strongly associated with digital gangrene in the discovery sample, a subsequent case-control study (with subjects matched 1:1 on disease duration) was designed for further exploration. Cases were patients with scleroderma and digital gangrene, while controls were patients with scleroderma and Raynaud's phenomenon alone (n = 39 matched pairs). Nonparametric, unadjusted matched pairs analysis as well as univariate and multivariable conditional logistic regression analyses were performed.

RESULTS

In the discovery sample, anti-IFI-16 antibodies were more prevalent in patients with scleroderma than in healthy controls (18% versus 2%; P = 0.01). Patients with anti-IFI-16 antibodies, compared to anti-IFI-16 antibody-negative patients, were more likely to have limited scleroderma (77% versus 46%; P = 0.03), a longer disease duration (median 15.2 years [interquartile range 10.6-18.3] versus 6.0 years [interquartile range 3.4-13.8]; P < 0.01), digital gangrene (24% versus 4%; P = 0.02), and a low diffusing capacity for carbon monoxide (DLco) (P < 0.01). In the case-control study, 35 (45%) of 78 patients were anti-IFI-16 antibody positive. Anti-IFI-16 antibody levels were significantly higher in cases with digital gangrene than in matched controls (P = 0.02). In analyses adjusted for age, cutaneous scleroderma subtype, smoking, and DLco, high anti-IFI-16 antibody levels were associated with the presence of digital gangrene (adjusted odds ratio 2.3, 95% confidence interval 1.0-5.6, P = 0.05). The odds of having digital gangrene increased with higher anti-IFI-16 antibody titers, in a dose-dependent manner.

CONCLUSION

Anti-IFI-16 antibodies are associated with digital gangrene in patients with scleroderma. Longitudinal prospective studies exploring anti-IFI-16 antibodies as a disease biomarker, and biologic studies investigating the pathogenicity of these antibodies, are warranted.

The Therapeutic Efficacy of Botulinum Toxin in Treating Scleroderma-Associated Raynaud's Phenomenon: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

OBJECTIVE

To assess the therapeutic efficacy of local injections of botulinum toxin type A (Btx-A) in improving blood flow to the hands of patients with Raynaud's phenomenon (RP) secondary to scleroderma.

METHODS

In this randomized, double-blind, placebo-controlled clinical trial, patients with scleroderma-associated RP received Btx-A (50 units in 2.5 ml sterile saline) in one randomly selected hand and sterile saline (2.5 ml) in the opposite hand. Follow-up at 1 and 4 months postinjection included laser Doppler imaging of hands, patient-reported outcomes, and physical examination. We compared outcomes using paired t-tests and population-average generalized models with generalized estimating equations.

RESULTS

Of 40 patients enrolled, 25 had limited scleroderma and 15 had diffuse scleroderma. From baseline to 1-month follow-up, there was a greater reduction in average blood flow in Btx-A-treated hands compared to placebo-treated hands. The model estimated that this difference was statistically significant (average difference -30.08 flux units [95% confidence interval -56.19, -3.98], P for interaction = 0.024). This difference was mainly influenced by patients with longstanding RP and diffuse scleroderma. Change in blood flow at 4-month follow-up was not significantly different between groups. Clinical measures (QuickDASH, McCabe Cold Sensitivity Score, pain on a visual analog scale, and Raynaud's Condition Score) improved slightly for Btx-A-treated hands.

CONCLUSION

Our laboratory-based laser Doppler imaging flow data do not support using Btx-A to treat RP in all scleroderma patients. The secondary clinical outcomes suggest some positive effect, but its clinical meaningfulness is questionable. The role of Btx-A in treating RP should be further studied with more homogeneous patient populations and in unique clinical situations such as acute digital ischemia.

Exhaled nitric oxide in pulmonary arterial hypertension associated with systemic sclerosis

The fractional exhaled concentration of nitric oxide (FE_NO) has been shown to be reduced in idiopathic pulmonary arterial hypertension (PAH) but has not been adequately studied in PAH associated with systemic sclerosis (SSc). We measured FE_NO at an expiratory flow rate of 50 mL/s in 21 treatment-naive patients with SSc-associated PAH (SSc-PAH), 94 subjects with SSc without pulmonary involvement, and 84 healthy volunteers. Measurements of FE_NO at additional flow rates of 100, 150, and 250 mL/s were obtained to derive the flow-independent nitric oxide exchange parameters of maximal airway flux (J'aw_NO) and steady-state alveolar concentration (CA_NO). FE_NO at 50 mL/s was similar (P = 0.22) in the SSc-PAH group (19 ± 12 parts per billion [ppb]) compared with the SSc group (17 ± 12 ppb) and healthy control group (21 ± 11 ppb). No change was observed after 4 months of targeted PAH therapy in 14 SSc-PAH group patients (P = 0.9). J'aw_NO was modestly reduced in SSc group subjects without lung disease (1.2 ± 0.5 nl/s) compared with healthy controls (1.64 ± 0.9; P < 0.05) but was similar to that in the SSc-PAH group. CA_NO was elevated in individuals with SSc-PAH (4.8 ± 2.6 ppb) compared with controls with SSc (3.3 ± 1.4 ppb) and healthy subjects (2.6 ± 1.5 ppb; P < 0.001 for both). However, after adjustment for the diffusing capacity of CO, there was no significant difference in CA_NO between individuals with SSc-PAH and controls with SSc. We conclude that FE_NO is not useful for the diagnosis of PAH in SSc. Increased alveolar nitric oxide in SSc-PAH likely represents impaired diffusion into pulmonary capillary blood.

Independent Association of Severity of Muscle Weakness With Disability as Measured by the Health Assessment Questionnaire Disability Index in Scleroderma

OBJECTIVE

To determine whether the presence and degree of muscle weakness in scleroderma is associated with disability.

METHODS

The study included a cohort of 1,718 scleroderma patients who had available data on muscle strength and disability. The primary independent variable was muscle weakness as defined by the maximum Medsger muscle severity score and the outcome was disability as measured by the last recorded Health Assessment Questionnaire disability index (HAQ DI) score. Univariate regression analyses were performed to assess the association of HAQ DI scores with the Medsger muscle severity score and other scleroderma characteristics. A multivariate regression analysis was performed to determine whether an association existed between the degree of muscle weakness and disability, while controlling for confounders.

RESULTS

In 1,718 patients with scleroderma, 22.8% (392 of 1,718) had muscle weakness, as defined by a Medsger muscle severity score of ≥1. This subset was more likely than those without weakness to have diffuse cutaneous scleroderma (55.6% versus 35.1%; P < 0.0001), higher modified Rodnan skin thickness scores (mean ± SD 16.3 ± 13.7 versus 10.3 ± 10.6; P < 0.00001), shorter disease duration (mean ± SD 5.21 ± 6.75 versus 6.22 ± 7.67 years; P = 0.02), synovitis (17.7% versus 11.4%; P = 0.001), forced vital capacity <70% (46.2% versus 30.6%; P = 0.0001), and higher creatine kinase values (mean ± SD 441 ± 1,211 versus 151 ± 255; P = 0.00001). Both univariate and multivariate analyses revealed that for every unit of increase in the Medsger muscle severity score, there was a clinically significant (minimum clinically important difference ± 0.14) increase in the mean HAQ DI score at last followup visit.

CONCLUSION

The presence of muscle weakness associates with several features of worse disease burden and independently associates with disability as measured by the HAQ DI.

Enrichment of Scleroderma Vascular Disease-Associated Autoantigens in Endothelial Lineage Cells

OBJECTIVE

Scleroderma patients with autoantibodies to CENPs and/or interferon-inducible protein 16 (IFI-16) are at increased risk of severe vascular complications. This study was undertaken to determine whether these autoantigens are enriched in cells of the vasculature.

METHODS

Successive stages of embryoid bodies (EBs) as well as vascular progenitors were used to evaluate the expression of scleroderma autoantigens IFI-16 and CENP by immunoblotting. CD31 was included to mark early blood vessels. IFI-16 and CD31 expression were defined in paraffin-embedded skin sections from scleroderma patients and from healthy controls. IFI-16 expression was determined by flow cytometric analysis in circulating endothelial cells (CECs) and circulating hematopoietic progenitor cells.

RESULTS

Expression of CENP-A, IFI-16, and CD31 was enriched in EBs on days 10 and 12 of differentiation, and particularly in cultures enriched in vascular progenitors (IFI-16, CD31, and CENPs A and B). This pattern was distinct from that of comparator autoantigens. Immunohistochemical staining of paraffin-embedded skin sections showed enrichment of IFI-16 in CD31-positive vascular endothelial cells in biopsy specimens from scleroderma patients and normal controls. Flow cytometric analysis revealed IFI-16 expression in circulating hematopoietic progenitor cells but minimal expression in CECs.

CONCLUSION

Our findings indicate that expression of the scleroderma autoantigens IFI-16 and CENPs, which are associated with severe vascular disease, is increased in vascular progenitors and mature endothelial cells. High level, lineage-enriched expression of autoantigens may explain the striking association between clinical phenotypes and the immune targeting of specific autoantigens.

Thrombotic complications after radial arterial line placement in systemic sclerosis: A case series

OBJECTIVE

To demonstrate potential thrombotic complications after radial arterial line placement in patients with scleroderma.

METHODS

This is a retrospective case series of 4 patients with scleroderma who were hospitalized in the intensive care unit (ICU) requiring invasive hemodynamic monitoring and developed severe complications after radial arterial line placement. We reviewed their medical records to assess their laboratory findings and clinical presentations.

RESULTS

All 4 patients met the 2013 ACR/EULAR criteria for systemic sclerosis and had a radial arterial line placement in the setting of invasive hemodynamic monitoring. Overall, 2 of 4 patients had arterial line placement during surgery; while 1 patient had it placed for invasive blood pressure monitoring during an ICU admission for renal crisis; and 1 patient had arterial line placement during cardiac resuscitation, but before administration of vasopressor support. In all, 3 of 4 patients had major ischemic events including digital gangrene, hand auto-amputation, and below-elbow amputation. Among all, 1 patient had temporary hand ischemia with recovery of perfusion with immediate arterial line removal within 24 hours.

CONCLUSIONS

Radial arterial line placement may trigger critical ischemic events in scleroderma patients. This experience suggests that placement of radial lines needs to be thoughtfully weighed prior to insertion in patients with scleroderma, and alternative options should be carefully considered.