Right Ventricular Functional Reserve in Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular (RV) functional reserve affects functional capacity and prognosis in patients with pulmonary arterial hypertension (PAH). PAH associated with systemic sclerosis (SSc-PAH) has a substantially worse prognosis than idiopathic PAH (IPAH), even though many measures of resting RV function and pulmonary vascular load are similar. We therefore tested the hypothesis that RV functional reserve is depressed in SSc-PAH patients.

METHODS AND RESULTS

RV pressure-volume relations were prospectively measured in IPAH (n=9) and SSc-PAH (n=15) patients at rest and during incremental atrial pacing or supine bicycle ergometry. Systolic and lusitropic function increased at faster heart rates in IPAH patients, but were markedly blunted in SSc-PAH. The recirculation fraction, which indexes intracellular calcium recycling, was also depressed in SSc-PAH (0.32±0.05 versus 0.50±0.05; P=0.039). At matched exercise (25 W), SSc-PAH patients did not augment contractility (end-systolic elastance) whereas IPAH did (P<0.001). RV afterload assessed by effective arterial elastance rose similarly in both groups; thus, ventricular-vascular coupling declined in SSc-PAH. Both end-systolic and end-diastolic RV volumes increased in SSc-PAH patients to offset contractile deficits, whereas chamber dilation was absent in IPAH (+37±10% versus +1±8%, P=0.004, and +19±4% versus -1±6%, P<0.001, respectively). Exercise-associated RV dilation also strongly correlated with resting ventricular-vascular coupling in a larger cohort.

CONCLUSIONS

RV contractile reserve is depressed in SSc-PAH versus IPAH subjects, associated with reduced calcium recycling. During exercise, this results in ventricular-pulmonary vascular uncoupling and acute RV dilation. RV dilation during exercise can predict adverse ventricular-vascular coupling in PAH patients.

Unique Abnormalities in Right Ventricular Longitudinal Strain in Systemic Sclerosis Patients

BACKGROUND

Cardiac involvement in systemic sclerosis (scleroderma [SSc]) adversely affects long-term prognosis, often remaining undetectable despite close clinical examination and 2-dimensional echocardiographic monitoring. Speckle-derived strain of the right ventricle (RV) was utilized to detect occult abnormalities in regional and global contractility in SSc patients.

METHODS AND RESULTS

A total of 138 SSc patients with technically adequate echocardiograms was studied and compared with 40 age- and sex-matched healthy non-SSc controls. Standard assessment of RV chamber function included tricuspid annular plane systolic excursion and fractional area change. RV longitudinal systolic speckle-derived strain was assessed in the basal, mid, and apical free wall. Tricuspid annular plane systolic excursion was not different between groups (P=0.307). Although fractional area change was lower in SSc patients than in controls (mean, 48.9 versus 55; P=0.002), the mean fractional area change was still within the normal range (>35). In contrast, RV longitudinal systolic speckle-derived strain measures were significantly different between groups, both globally (-20.4% versus -17.7%; P=0.005) and regionally: they were decreased in the apex (-8.5% versus -17.1%; P<0.0001) and mid segments (-12.4% versus -20.9%; P<0.0001), and increased in the base (-32.2% versus -23.3%; P=0.0001) for the SSc group. The regional difference in the base compared with the apex was significantly greater for SSc than for controls (P<0.0001 for interaction). The differences observed in regional strain between SSc and control were unchanged after adjusting for RV systolic pressure.

CONCLUSIONS

Speckle-derived strain reveals a heterogenous pattern of regional heart strain in SSc that is not detected by conventional measures of function, suggestive of occult RV myocardial disease.

Frequency of circulating topoisomerase-I-specific CD4 T cells predicts presence and progression of interstitial lung disease in scleroderma

Background

Scleroderma is an antigen-driven T cell-mediated autoimmune disease. Presence of anti-topoisomerase-I antibodies is associated with pulmonary fibrosis and predicts increased mortality. Characterization of autoreactive T lymphocytes may shed light on disease pathogenesis and serve as a biomarker for disease activity. Here, we aimed to quantify and functionally characterize circulating topoisomerase I (topo-I)-specific CD4+ T cells and to define their association with presence and progression of interstitial lung disease (ILD) in patients with scleroderma.

Methods

Using flow cytometry, circulating topo-I-reactive CD4+ T cells were identified by the expression of specific activation markers (CD154 and CD69) upon stimulation with purified topo-I and quantified in 27 SSc patients and 4 healthy donors (HD). Polarization of autoreactive T cells (Th1, Th2, Th17, Th1–17) was defined using surface expression of specific chemokine receptors. Presence and progression of ILD were determined using high-resolution chest CT and pulmonary function tests.

Results

Topo-I-reactive CD4+ T cells were found in all topo-I-positive patients compared to one topo-I-negative subject and no HD. Topo-I-specific CD4+ T cells exhibited a distinct Th17 polarized phenotype. Autoreactive T cells were significantly increased in subjects with evidence of ILD and were quantitatively associated with the decline of lung volumes.

Conclusions

Topo-I-specific T cells can be reliably quantified in the peripheral blood of patients with scleroderma, exhibit a pro-inflammatory Th17 phenotype, and predict progression of ILD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-0993-2) contains supplementary material, which is available to authorized users.

Genetic susceptibility loci of idiopathic interstitial pneumonia do not represent risk for systemic sclerosis: a case control study in Caucasian patients

BACKGROUND

Systemic sclerosis (SSc)-related interstitial lung disease (ILD) has phenotypic similarities to lung involvement in idiopathic interstitial pneumonia (IIP). We aimed to assess whether genetic susceptibility loci recently identified in the large IIP genome-wide association studies (GWASs) were also risk loci for SSc overall or severity of ILD in SSc.

METHODS

A total of 2571 SSc patients and 4500 healthy controls were investigated from the US discovery GWAS and additional US replication cohorts. Thirteen IIP-related selected single nucleotide polymorphisms (SNPs) were genotyped and analyzed for their association with SSc.

RESULTS

We found an association of SSc with the SNP rs6793295 in the LRRC34 gene (OR = 1.14, CI 95 % 1.03 to 1.25, p value = 0.009) and rs11191865 in the OBFC1 gene (OR = 1.09, CI 95 % 1.00 to 1.19, p value = 0.043) in the discovery cohort. Additionally, rs7934606 in MUC2 (OR = 1.24, CI 95 % 1.01 to 1.52, p value = 0.037) was associated with SSc-ILD defined by imaging. However, these associations failed to replicate in the validation cohort. Furthermore, SNPs rs2076295 in DSP (β = -2.29, CI 95 % -3.85 to -0.74, p value = 0.004) rs17690703 in SPPL2C (β = 2.04, CI 95 % 0.21 to 3.88, p value = 0.029) and rs1981997 in MAPT (β = 2.26, CI 95 % 0.35 to 4.17, p value = 0.02) were associated with percent predicted forced vital capacity (FVC%) even after adjusting for the anti-topoisomerase (ATA)-positive subset. However, these associations also did not replicate in the validation cohort.

CONCLUSIONS

Our results add new evidence that SSc and SSc-related ILD are genetically distinct from IIP, although they share phenotypic similarities.

Spectrum of Muscle Histopathologic Findings in Forty-Two Scleroderma Patients With Weakness

OBJECTIVE

To determine if distinct muscle pathologic features exist in scleroderma subjects with weakness.

METHODS

This retrospective study included weak scleroderma subjects with muscle biopsies available for review. Biopsies were systematically assessed for individual pathologic features, including inflammation, necrosis, fibrosis, and acute neurogenic atrophy. Based on the aggregate individual features, biopsies were assigned a histopathologic category of polymyositis, dermatomyositis, necrotizing myopathy, nonspecific myositis, "acute denervation," "fibrosis only," or "other." Clinical data analyzed included autoantibody profiles, scleroderma subtype and disease duration, Medsger muscle severity scores, creatine kinase, electromyography, and muscle magnetic resonance imaging.

RESULTS

A total of 42 subjects (79% female and 64% diffuse scleroderma) were included in this study. Necrosis (67%), inflammation (48%), acute neurogenic atrophy (48%), and fibrosis (33%) were the most prevalent pathologic features. The presence of fibrosis was strongly associated with anti-PM-Scl antibodies. Histopathologic categories included nonspecific myositis (36%), necrotizing myopathy (21%), dermatomyositis (7%), "acute denervation" (7%), "fibrosis only" (7%), and polymyositis (5%). Disease duration of scleroderma at the time of muscle biopsy was shorter in polymyositis than other histopathologic categories. Patients with anti-PM-Scl and Scl-70 antibodies also had a shorter disease duration than those with other autoantibody profiles.

CONCLUSION

Nonspecific myositis and necrotizing myopathy were the most common histopathologic categories in weak scleroderma subjects. Surprisingly, nearly half of the subjects studied had histologic evidence of acute motor denervation (acute neurogenic atrophy); this has not been previously reported. Taken together, these observations suggest that a variety of pathologic mechanisms may underlie the development of myopathy in scleroderma.

Biomarkers of pulmonary hypertension in patients with scleroderma: a case-control study

Introduction

Significant pulmonary vascular disease is a leading cause of death in patients with scleroderma, and early detection and early medical intervention are important, as they may delay disease progression and improve survival and quality of life. Although several biomarkers have been proposed, there remains a need to define a reliable biomarker of early pulmonary vascular disease and subsequent development of pulmonary hypertension (PH). The purpose of this study was to define potential biomarkers for clinically significant pulmonary vascular disease in patients with scleroderma.

Methods

The circulating growth factors basic fibroblast growth factor, placental growth factor (PlGF), vascular endothelial growth factor (VEGF), hepatocyte growth factor, and soluble VEGF receptor 1 (sFlt-1), as well as cytokines (interleukin [IL]-1β IL-2, IL-4, IL-5, IL-8, IL-10, IL-12, IL-13, tumor necrosis factor-α, and interferon-γ), were quantified in patients with scleroderma with PH (n = 37) or without PH (n = 40). In non-parametric unadjusted analyses, we examined associations of growth factor and cytokine levels with PH. In a subset of each group, a second set of earlier samples, drawn 3.0±1.6 years earlier, were assessed to determine the changes over time.

Results

sFlt-1 (p = 0.02) and PlGF (p = 0.02) were higher in the PH than in the non-PH group. sFlt-1 (ρ = 0.3245; p = 0.01) positively correlated with right ventricular systolic pressure. Both PlGF (p = 0.03) and sFlt-1 (p = 0.04) positively correlated with the ratio of forced vital capacity to diffusing capacity for carbon monoxide (DLCO), and both inversely correlated with DLCO (p = 0.01). Both PlGF and sFlt-1 levels were stable over time in the control population.

Conclusions

Our study demonstrated clear associations between regulators of angiogenesis (sFlt-1 and PlGF) and measures of PH in scleroderma and that these growth factors are potential biomarkers for PH in patients with scleroderma. Larger longitudinal studies are required for validation of our results.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0712-4) contains supplementary material, which is available to authorized users.

Pilot study to determine whether transient receptor potential melastatin type 8 (TRPM8) antibodies are detected in scleroderma

OBJECTIVES

A key mediator in cold-sensation is the protein transient receptor potential melastatin 8 (TRPM8), which is expressed on sensory nerves and cutaneous blood vessels. These receptors are activated by cold temperatures and play a key role in body thermoregulation. Cold sensitivity and Raynaud's phenomenon are frequent clinical features in scleroderma, and are thought to be secondary to a local defect in cutaneous thermoregulation. We investigated whether autoantibodies targeting TRPM8 were present in the sera of patients with scleroderma as evidence for a possible mechanism for an acquired immune mediated defect in thermoregulation.

METHODS

Sera from 50 well-characterised scleroderma patients with Raynaud's phenomenon were studied. TRPM8 autoantibodies were assayed as follows: 1. immunoprecipitation with 35S-methionine-labelled TRPM8 generated by in vitro transcription and translation, 2. immunoblotting lysates made from cells transiently transfected with TRPM8 cDNA, 3. Immunoprecipitation of TRPM8 transfected lysates with detection by blotting and 4. flow cytometry.

RESULTS

Fifty scleroderma patients with Raynaud's phenomenon (41 female, 39 Caucasian, 23 with limited scleroderma, and 20 with history of cancer) were studied. Four different methods to assay for TRPM8 antibodies were set up, optimised and validated using commercial antibodies. All 50 scleroderma patients' sera were assayed using each of the above methods, and all were negative for TRPM8 autoantibodies.

CONCLUSIONS

Antibodies against TRPM8 are not found in scleroderma patient sera, suggesting that the abnormal cold sensitivity and associated abnormal vascular reactivity in scleroderma patients is not the result of an immune process targeting TRPM8.

Examination of autoantibody status and clinical features associated with cancer risk and cancer-associated scleroderma

OBJECTIVE

We previously reported a contemporaneous onset of cancer and scleroderma in patients with anti-RNA polymerase III antibodies, and we identified a biologic link between cancer and scleroderma. This investigation was designed to further evaluate whether autoantibody status and other characteristics are associated with cancer and a clustering of cancer with scleroderma onset.

METHODS

Logistic regression analysis was performed to assess the relationship of 2 outcomes, cancer (model 1) and a short (±2 years) cancer-scleroderma interval (model 2), with autoantibody status and scleroderma covariates.

RESULTS

Of 1,044 scleroderma patients, 168 (16.1%) had cancer. In the adjusted model 1, only older age at scleroderma onset (odds ratio 1.04 [95% confidence interval 1.02-1.05]) and white race (odds ratio 2.71 [95% confidence interval 1.22-6.04]) were significantly associated with an increased overall risk of cancer. In the adjusted model 2, only anti-RNA polymerase III positivity (odds ratio 5.08 [95% confidence interval 1.60-16.1]) and older age at scleroderma onset (odds ratio 1.04 [95% confidence interval 1.00-1.08]) were significantly associated with a short cancer-scleroderma interval. While anti-RNA polymerase III positivity was associated with a short cancer-scleroderma interval independent of age at scleroderma onset, the cancer-scleroderma interval shortened with older age at scleroderma onset in other antibody groups (Spearman's correlation P < 0.05), particularly among patients with anti-topoisomerase I antibodies and patients who were negative for anticentromere, anti-topoisomerase I, and anti-RNA polymerase III antibodies.

CONCLUSION

Increased age at scleroderma onset is strongly associated with cancer risk overall. While anti-RNA polymerase III status is an independent marker of coincident cancer and scleroderma at any age, a clustering of cancer with scleroderma is also seen in patients with anti-topoisomerase I and other autoantibody specificities who develop scleroderma at older ages.

Intravenous immunoglobulin may be an effective therapy for refractory, active diffuse cutaneous systemic sclerosis

OBJECTIVE

We sought to retrospectively review a single-center experience using intravenous immunoglobulin (IVIG) for the treatment of refractory, active diffuse cutaneous systemic sclerosis (dcSSc).

METHODS

The mean modified Rodnan Skin score (mRSS) at baseline was compared to the mRSS at 6, 12, 18, and 24 months post-IVIG initiation by the paired Student t test. Changes in mRSS at 6 and 12 months were also compared to data from historical controls of 3 large, negative, multicenter, randomized clinical trials of other medications [D-penicillamine (D-pen), recombinant human relaxin (relaxin), and oral bovine type I collagen (collagen)] and to patients treated with mycophenolate mofetil (MMF) alone using the Student t test.

RESULTS

Thirty patients were treated with adjunctive IVIG (2 g/kg/mo) for refractory, active dcSSc. The mean baseline mRSS of our cohort was 29.6 ± 7.2, and this significantly decreased to 24.1 ± 9.6 (n = 29, p = 0.0011) at 6 months, 22.5 ± 10.0 (n = 25, p = 0.0001) at 12 months, 20.6 ± 11.8 (n = 23, p = 0.0001) at 18 months, and 15.3 ± 6.4 (n = 15, p < 0.0001) at 24 months. The mean change in mRSS at 6 months was not significantly different in the IVIG group (-5.3 ± 7.9) compared to the relaxin trial (-4.8 ± 6.99, p = 0.74) or MMF group (-3.4 ± 7.4, p = 0.26); however, at 12 months, the mean change in mRSS was significantly better in the IVIG group (-8 ± 8.3) than in the D-pen (-2.47 ± 8.6, p = 0.005) and collagen (-3.4 ± 7.12, p = 0.005) groups, and was comparable to the group of primary MMF responders (-7.1 ± 9, p = 0.67).

CONCLUSION

Our observational study suggests that IVIG may be an effective adjunctive therapy for active dcSSc in patients failing other therapies.

Severity of systemic sclerosis-associated pulmonary arterial hypertension in African Americans

African Americans (AA) with systemic sclerosis (SSc) have a worse prognosis compared to Americans of European descent (EA). We conducted the current study to test the hypothesis that AA patients with SSc have more severe disease and poorer outcomes compared to EA patients when afflicted with pulmonary arterial hypertension (PAH). We studied 160 consecutive SSc patients with PAH diagnosed by right heart catheterization, comparing demographics, hemodynamics, and outcomes between AA and EA patients. The cohort included 29 AA and 131 EA patients with similar baseline characteristics except for increased prevalence of diffuse SSc in AA. AA patients had worse functional class (FC) (80% FC III-IV vs 53%; p = 0.02), higher brain natriuretic peptide (NT-pro-BNP) (5729 ± 9730 pg/mL vs 1892 ± 2417 pg/mL; p = 0.02), more depressed right ventricular function, a trend toward lower 6-minute walk distance (263 ± 111  m vs 333 ± 110  m; p = 0.07), and worse hemodynamics (cardiac index 1.95 ± 0.58 L/min/m vs 2.62 ± 0.80 L/min/m; pulmonary vascular resistance 10.3 ± 6.2 WU vs 7.6 ± 5.0 WU; p  < 0.05) compared with EA patients. Kaplan-Meier survival estimates for AA and EA patients, respectively, were 62% vs 73% at 2 years and 26% vs 44% at 5 years (p  > 0.05). In conclusion, AA patients with SSc-PAH are more likely to have diffuse SSc and to present with significantly more severe PAH compared with EA patients. AA patients also appear to have poorer survival, though larger studies are needed to investigate this association definitively.

Association of the autoimmune disease scleroderma with an immunologic response to cancer

Autoimmune diseases are thought to be initiated by exposures to foreign antigens that cross-react with endogenous molecules. Scleroderma is an autoimmune connective tissue disease in which patients make antibodies to a limited group of autoantigens, including RPC1, encoded by the POLR3A gene. As patients with scleroderma and antibodies against RPC1 are at increased risk for cancer, we hypothesized that the "foreign" antigens in this autoimmune disease are encoded by somatically mutated genes in the patients' incipient cancers. Studying cancers from scleroderma patients, we found genetic alterations of the POLR3A locus in six of eight patients with antibodies to RPC1 but not in eight patients without antibodies to RPC1. Analyses of peripheral blood lymphocytes and serum suggested that POLR3A mutations triggered cellular immunity and cross-reactive humoral immune responses. These results offer insight into the pathogenesis of scleroderma and provide support for the idea that acquired immunity helps to control naturally occurring cancers.

Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis

In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci.

Novel investigational agents for the treatment of scleroderma

INTRODUCTION

The purpose of this article is to highlight novel therapies that are being used in scleroderma (SSc). Therapeutic interventions in SSc generally target at least one of three ongoing biological processes characteristic of the disease: vasculopathy, autoimmunity and tissue fibrosis. Treatment decisions in SSc are determined by the level of disease activity and the degree of specific organ involvement. Traditional therapy has primarily focused on organ-specific management without clear evidence of overall disease modification.

AREAS COVERED

The authors provide a review of a variety of agents, which are already used for other autoimmune diseases, that are now being used to treat active SSc skin or lung disease, including rituximab, tocilizumab and IVIG. Several agents studied in vitro and in animal models of fibrosis have shown promise, including bortezomib, LPA-1 antagonists, anti-CCN2 therapy, anti-IL-13 and thrombin antagonists. The authors also provide details on targeting intracellular molecular pathways and matricellular proteins, which is another novel area of investigation.

EXPERT OPINION

Combination therapy may be necessary to control the complex biological network active in SSc. Most of the current evidence that suggest benefit of these agents is based on small population studies. Ultimately well-designed clinical trials are required to define the role of these agents in treating SSc.

Right ventricular dysfunction in systemic sclerosis-associated pulmonary arterial hypertension

BACKGROUND

Systemic sclerosis–associated pulmonary artery hypertension (SScPAH) has a worse prognosis compared with idiopathic pulmonary arterial hypertension (IPAH), with a median survival of 3 years after diagnosis often caused by right ventricular (RV) failure. We tested whether SScPAH or systemic sclerosis–related pulmonary hypertension with interstitial lung disease imposes a greater pulmonary vascular load than IPAH and leads to worse RV contractile function.

METHODS AND RESULTS

We analyzed pulmonary artery pressures and mean flow in 282 patients with pulmonary hypertension (166 SScPAH, 49 systemic sclerosis–related pulmonary hypertension with interstitial lung disease, and 67 IPAH). An inverse relation between pulmonary resistance and compliance was similar for all 3 groups, with a near constant resistance×compliance product. RV pressure–volume loops were measured in a subset, IPAH (n=5) and SScPAH (n=7), as well as SSc without PH (n=7) to derive contractile indexes (end-systolic elastance [Ees] and preload recruitable stroke work [Msw]), measures of RV load (arterial elastance [Ea]), and RV pulmonary artery coupling (Ees/Ea). RV afterload was similar in SScPAH and IPAH (pulmonary vascular resistance=7.0±4.5 versus 7.9±4.3 Wood units; Ea=0.9±0.4 versus 1.2±0.5 mm Hg/mL; pulmonary arterial compliance=2.4±1.5 versus 1.7±1.1 mL/mm Hg; P>0.3 for each). Although SScPAH did not have greater vascular stiffening compared with IPAH, RV contractility was more depressed (Ees=0.8±0.3 versus 2.3±1.1, P<0.01; Msw=21±11 versus 45±16, P=0.01), with differential RV-PA uncoupling (Ees/Ea=1.0±0.5 versus 2.1±1.0; P=0.03). This ratio was higher in SSc without PH (Ees/Ea=2.3±1.2; P=0.02 versus SScPAH).

CONCLUSIONS

RV dysfunction is worse in SScPAH compared with IPAH at similar afterload, and may be because of intrinsic systolic function rather than enhanced pulmonary vascular resistive and pulsatile loading.

Integrin-modulating therapy prevents fibrosis and autoimmunity in mouse models of scleroderma

In systemic sclerosis (SSc), a common and aetiologically mysterious form of scleroderma (defined as pathological fibrosis of the skin), previously healthy adults acquire fibrosis of the skin and viscera in association with autoantibodies. Familial recurrence is extremely rare and causal genes have not been identified. Although the onset of fibrosis in SSc typically correlates with the production of autoantibodies, whether they contribute to disease pathogenesis or simply serve as a marker of disease remains controversial and the mechanism for their induction is largely unknown. The study of SSc is hindered by a lack of animal models that recapitulate the aetiology of this complex disease. To gain a foothold in the pathogenesis of pathological skin fibrosis, we studied stiff skin syndrome (SSS), a rare but tractable Mendelian disorder leading to childhood onset of diffuse skin fibrosis with autosomal dominant inheritance and complete penetrance. We showed previously that SSS is caused by heterozygous missense mutations in the gene (FBN1) encoding fibrillin-1, the main constituent of extracellular microfibrils. SSS mutations all localize to the only domain in fibrillin-1 that harbours an Arg-Gly-Asp (RGD) motif needed to mediate cell-matrix interactions by binding to cell-surface integrins. Here we show that mouse lines harbouring analogous amino acid substitutions in fibrillin-1 recapitulate aggressive skin fibrosis that is prevented by integrin-modulating therapies and reversed by antagonism of the pro-fibrotic cytokine transforming growth factor β (TGF-β). Mutant mice show skin infiltration of pro-inflammatory immune cells including plasmacytoid dendritic cells, T helper cells and plasma cells, and also autoantibody production; these findings are normalized by integrin-modulating therapies or TGF-β antagonism. These results show that alterations in cell-matrix interactions are sufficient to initiate and sustain inflammatory and pro-fibrotic programmes and highlight new therapeutic strategies.

Race and association with disease manifestations and mortality in scleroderma: a 20-year experience at the Johns Hopkins Scleroderma Center and review of the literature

Experience suggests that African Americans may express autoimmune disease differently than other racial groups. In the context of systemic sclerosis (scleroderma), we sought to determine whether race was related to a more adverse expression of disease. Between January 1, 1990, and December 31, 2009, a total of 409 African American and 1808 white patients with scleroderma were evaluated at a single university medical center. While the distribution by sex was virtually identical in both groups, at 82% female, African American patients presented to the center at a younger mean age than white patients (47 vs. 53 yr; p < 0.001). Two-thirds of white patients manifested the limited cutaneous subset of disease, whereas the majority of African American patients manifested the diffuse cutaneous subset (p < 0.001). The proportion seropositive for anticentromere antibody was nearly 3-fold greater among white patients, at 34%, compared to African American patients (12%; p < 0.001). Nearly a third of African American (31%) patients had autoantibodies to topoisomerase, compared to 19% of white patients (p = 0.001). Notably, African American patients experienced an increase in prevalence of cardiac (adjusted odds ratio [OR], 1.6; 95% confidence interval [CI], 1.3-2.2), renal (OR, 1.6; 95% CI, 1.2-2.1), digital ischemia (OR, 1.5; 95% CI, 1.4-2.2), muscle (OR, 1.7; 95% CI, 1.3-2.3), and restrictive lung (OR, 6.9; 95% CI, 5.1-9.4) disease. Overall, 700 (32%) patients died (159 African American; 541 white). The cumulative incidence of mortality at 10 years was 43% among African American patients compared to 35% among white patients (log-rank p = 0.0011). Compared to white patients, African American patients experienced an 80% increase in risk of mortality (relative risk [RR], 1.8; 95% CI, 1.4-2.2), after adjustment for age at disease onset and disease duration. Further adjustment by sex, disease subtype, and scleroderma-specific autoantibody status, and for the socioeconomic measures of educational attainment and health insurance status, diminished these risk estimates (RR, 1.3; 95% CI, 1.0-1.6). The heightened risk of mortality persisted in strata defined by age at disease onset, diffuse cutaneous disease, anticentromere seropositivity, decade of care at the center, and among women. These findings support the notion that race is related to a distinct phenotypic profile in scleroderma, and a more unfavorable prognosis among African Americans, warranting heightened diagnostic evaluation and vigilant care of these patients. Further, we provide a chronologic review of the literature regarding race, organ system involvement, and mortality in scleroderma; we furnish synopses of relevant reports, and summarize findings.

The degree of skin involvement identifies distinct lung disease outcomes and survival in systemic sclerosis

OBJECTIVE

To determine whether the pattern of skin involvement can predict clinical features, risk of restrictive lung disease (RLD) and survival in a large scleroderma (SSc) cohort.

METHODS

Demographic and clinical data collected over 30 years from 2205 patients with SSc were retrospectively analysed after subdividing subjects into four subtypes based on pattern of skin fibrosis: type 0 (no skin involvement), type 1 (limited to metacarpophalangeal joints), type 2 (distal to elbows/knees) and type 3 (proximal to elbows/knees). Clinical features associated with skin subsets were identified by regression analyses. Kaplan-Meier and Cox proportional hazards models were used to compare time to RLD and survival across subtypes.

RESULTS

The presence and severity of RLD were positively associated with skin subtype (p<0.001). RLD prevalence incrementally ranged from 51.9% in type 0 to 76.7% in type 3 (p<0.001). Type 2 SSc exhibited a distinct phenotype with intermediate risk for RLD relative to type 1 (higher, p<0.001) and type 3 (lower, p<0.001) and a unique autoantibody profile, with a prevalence of anticentromere antibodies lower than type 1 (28.9% vs 44.1%, p=0.001) and of anti-topoisomerase I antibodies similar to type 3 (32.8% vs 28.7%, p=0.38). These autoantibodies were also found to be significant negative (OR=0.33, p<0.001) and positive (OR=1.6, p=0.01) predictors of RLD risk, respectively. Mortality was also intermediate in type 2 patients relative to type 3 (p=0.0003) and type 1 (p=0.066).

CONCLUSIONS

These data suggest that the current classification subdividing SSc into limited and diffuse cutaneous subtypes misclassifies an intermediate group of patients exhibiting unique autoantibody profile, disease course and clinical outcomes.

My approach to the treatment of scleroderma

Systemic sclerosis (scleroderma) is unique among the rheumatic diseases because it presents the challenge of managing a chronic multisystem autoimmune disease with a widespread obliterative vasculopathy of small arteries that is associated with varying degrees of tissue fibrosis. The hallmark of scleroderma is clinical heterogeneity with subsets that vary in the degree of disease expression, organ involvement, and ultimate prognosis. Thus, the term scleroderma is used to describe patients who have common manifestations that link them together, whereas a highly variable clinical course exists that spans from mild and subtle findings to aggressive, life-threatening multisystem disease. The physician needs to carefully characterize each patient to understand the specific manifestations and level of disease activity to decide appropriate treatment. This is particularly important in treating a patient with scleroderma because there is no treatment that has been proven to modify the overall disease course, although therapy that targets specific organ involvement early before irreversible damage occurs improves both quality of life and survival. This review describes our approach as defined by evidence, expert opinion, and our experience treating patients. Scleroderma is a multisystem disease with variable expression; thus, any treatment plan must be holistic, yet at the same time focus on the dominant organ disease. The goal of therapy is to improve quality of life by minimizing specific organ involvement and subsequent life-threatening disease. At the same time the many factors that alter daily function need to be addressed, including nutrition, pain, deconditioning, musculoskeletal disuse, comorbid conditions, and the emotional aspects of the disease, such as fear, depression, and the social withdrawal caused by disfigurement.

A multi-centre, blinded, randomised, placebo-controlled, laboratory-based study of MQX-503, a novel topical gel formulation of nitroglycerine, in patients with Raynaud phenomenon

Objective

MQX-503 is a novel nitroglycerine preparation designed to absorb quickly and allow local vasodilatation in the skin. We examined the efficacy and tolerability of this medication in Raynaud phenomenon (RP) in a laboratory-based study.

Methods

In this multi-centre, double-blind, randomised, placebo-controlled, cross-over study, subjects were treated with 0.5% or 1.25% nitroglycerine or placebo gel. Subjects received each dose twice in a randomised order. Each study session consisted of baseline laser Doppler measurements, study gel application and 5 min of cold chamber exposure (−20°C). Blood flow (BF) was measured at the end of exposure and for the next 120 min at set intervals. Other outcome measures included achievement of baseline BF; the time to achieve 50% and 70% baseline skin temperature (ST); and pain, tingling and numbness scores.

Results

37 subjects completed 214 treatment periods. Time to achieve baseline BF was significantly shorter in the two treated groups (HR=1.77 and 2.02 for 0.5% and 1.25% vs placebo, respectively). The proportion of subjects achieving baseline BF was 45.8% for placebo, 66.2% for 0.5% and 69% for 1.25% (p=0.01 and p=0.002 for 0.5% and 1.25% vs placebo, respectively). No meaningful differences were seen in ST or pain/numbness/tingling scores. Treatment was well tolerated with no serious adverse events.

Conclusions

Treatment with MQX-503 caused a significant improvement in skin BF compared with placebo. Data from this proof of concept study suggest benefit of MQX-503 in subjects with RP.

Changes in estimated right ventricular systolic pressure predict mortality and pulmonary hypertension in a cohort of scleroderma patients

OBJECTIVES

Annual echocardiography screening is widely used in scleroderma, but the utility of longitudinal assessment is unknown. We evaluated whether change in right ventricular systolic pressure (RVSP) was a risk factor for mortality and development of pulmonary arterial hypertension (PAH) in a cohort of scleroderma patients.

METHODS

The study population consisted of scleroderma patients who had at least three echocardiograms and pulmonary function tests (PFTs) over ≥1 year as part of routine care. The annual rate of change in RVSP was determined for each subject. Cox proportional hazards regression was performed to assess the association between PAH and mortality and change in RVSP/year, adjusted for relevant covariates.

RESULTS

613 scleroderma patients with 3244 echocardiograms were studied. The adjusted relative hazards of PAH and mortality were 1.08 (95% CI 1.05-1.11) and 1.12 (95% CI 1.08-1.15) per 1 mm Hg increase in RVSP/year, respectively. Compared with patients with a stable RVSP, the relative hazards for the development of PAH were 1.90 (95% CI 0.91-3.96), 5.09 (95% CI 2.53-10.26) and 6.15 (95% CI 3.58-10.56) for subjects whose RVSP increased at rates of 1-1.99, 2-2.99 and 3+ mm Hg/year. Compared with the same reference group, the relative hazards for death were 0.92 (95% CI 0.48-1.73), 2.16 (95% CI 1.16-4.01) and 5.05 (95% CI 3.47-7.34) for subjects whose RVSP increased at rates of 1-1.99, 2-2.99 and 3+ mm Hg/year.

CONCLUSIONS

In a population of scleroderma patients, the rate of increase in RVSP is a risk factor for mortality and PAH even after adjustment for clinical characteristics and longitudinal PFT data.

IRF5 polymorphism predicts prognosis in patients with systemic sclerosis

OBJECTIVE

The first genome-wide association study (GWAS) of systemic sclerosis (SSc) demonstrated three non-major histocompatibility complex (MHC) susceptibility loci. The goal of this study was to investigate the impact of these gene variants on survival and severity of interstitial lung disease (ILD) in SSc.

METHODS

The authors examined 1443 Caucasian SSc patients enrolled in the Genetics versus Environment In Scleroderma Outcome Study (GENISOS) and Scleroderma Family Registry (n = 914 - discovery cohort) and The Johns Hopkins Scleroderma Cohort (n = 529 - replication cohort). Forced vital capacity (FVC)% predicted was used as a surrogate for ILD severity. Five single nucleotide polymorphisms, IRF5 (rs10488631, rs12537284, rs4728142), STAT4 (rs3821236), CD247 (rs2056626) reached genome-wide significance in the SSc-GWAS and were examined in the current study.

RESULTS

Overall, 15.5% of the patients had died over the follow-up period of 5.5 years. The IRF5 rs4728142 minor allele was predictive of longer survival in the discovery cohort (p = 0.021) and in the independent replication cohort (p = 0.047) and combined group (HR: 0.75, 95% CI 0.62 to 0.90, p = 0.002). The association of this SNP with survival was independent of age at disease onset, disease type and autoantibody profile (anticentromere and antitopoisomerase antibodies). The minor allele frequency of IRF5 rs4728142 was 49.4%. Moreover, IRF5 rs4728142 minor allele correlated with higher FVC% predicted at enrolment (p = 0.019). Finally, the IRF5 rs4728142 minor allele was associated with lower IRF5 transcript expression in patients and controls (p = 0.016 and p = 0.034, respectively), suggesting that the IRF5, rs4728142 SNP, may be functionally relevant.

CONCLUSION

An SNP in the IRF5 promoter region (rs4728142), associated with lower IRF5 transcript levels, was predictive of longer survival and milder ILD in patients with SSc.