High-dose versus low-dose ?-penicillamine in early diffuse systemic sclerosis trial: lessons learned

Neurological, cardiac, musculoskeletal, and renal manifestations of scleroderma along with insights into its genetics, pathophysiology, diagnostic, and therapeutic updates

Background

Scleroderma, also referred to as systemic sclerosis, is a multifaceted autoimmune condition characterized by abnormal fibrosis and impaired vascular function. Pathologically, it encompasses the persistent presence of inflammation, abnormal collagen buildup, and restructuring of blood vessels in various organs, resulting in a wide range of clinical symptoms. This review incorporates the most recent scientific literature on scleroderma, with a particular emphasis on its pathophysiology, clinical manifestations, diagnostic approaches, and treatment options.

Methodology

A comprehensive investigation was carried out on numerous databases, such as PubMed, MEDLINE, Scopus, Web of Science, and Google Scholar, to collect pertinent studies covering diverse facets of scleroderma research.

Results

Scleroderma presents with a range of systemic manifestations, such as interstitial lung disease, gastrointestinal dysmotility, Raynaud's phenomenon, pulmonary arterial hypertension, renal complications, neurological symptoms, and cardiac abnormalities. Serological markers, such as antinuclear antibodies, anti-centromere antibodies, and anti-topoisomerase antibodies, are important for classifying diseases and predicting their outcomes.

Discussion

The precise identification of scleroderma is crucial for promptly and correctly implementing effective treatment plans. Treatment approaches aim to improve symptoms, reduce complications, and slow down the progression of the disease. An integrated approach that combines pharmacological agents, including immunosuppressants, endothelin receptor antagonists, and prostanoids, with nonpharmacological interventions such as physical and occupational therapy is essential for maximizing patient care.

Conclusion

Through the clarification of existing gaps in knowledge and identification of emerging trends, our goal is to improve the accuracy of diagnosis, enhance the effectiveness of therapeutic interventions, and ultimately enhance the overall quality of life for individuals suffering from scleroderma. Ongoing cooperation and creative research are necessary to advance the field and achieve improved patient outcomes and new therapeutic discoveries.

Patient and Physician Global Assessments of Disease Status in Systemic Sclerosis

Global assessments of disease by both patients and physicians are widely used in clinical studies of systemic sclerosis (SSc). They are commonly secondary end points in randomized controlled trials (RCTs) and are considered important items in composite measures of treatment response. A comprehensive literature review was conducted of the formats, wording, and clinimetric properties of the patient global assessment of disease status (PtGA) and physician global assessment of disease status (PhGA) used in RCTs of SSc. Marked heterogeneity was found in the wording and measurement scales of the global assessments applied in RCTs. These instruments were not developed using rigorous methodology and have not been fully validated. There is a pressing need for standardization and validation of patient and physician global assessment tools in SSc to enable universal application of these measures across RCTs in SSc.

Fibrosis in Mesothelioma: Potential Role of Lysyl Oxidases

Immunotherapies (such as checkpoint inhibitors) and standard chemotherapies (such as cisplatin) have limitations in the successful treatment of malignant pleural mesothelioma (MPM). Fibrosis is the accumulation of collagen in the extracellular matrix (ECM) of tissues, making them denser than that of healthy tissues and thereby affecting drug delivery and immune cell infiltration. Moreover, fibrosis severely affects the patient's breathing and quality of life. The production of collagen and its assembly is highly regulated by various enzymes such as lysyl oxidases. Many solid tumors aberrantly express the family of lysyl oxidases (LOX/LOXL). This review examines how LOX/LOXLs were found to be dysregulated in noncancerous and cancerous settings, discusses their roles in solid tumor fibrosis and pathogenesis and explores the role of fibrosis in the development and poor clinical outcomes of patients with MPM. We examine the current preclinical status of drugs targeting LOX/LOXLs and how the incorporation of such drugs may have therapeutic benefits in the treatment and management of patients with MPM.

Hematopoietic Stem Cell Transplantation Improves Functional Outcomes of Systemic Sclerosis Patients

BACKGROUND/OBJECTIVE

We sought to evaluate if autologous hematopoietic stem cell transplantation (AHSCT) influences the functional status of systemic sclerosis (SSc) patients.

METHODS

From 2014 to 2018, a cohort of 27 SSc patients was assessed before, and at 6 and 12 months after AHSCT for modified Rodnan's skin score (mRSS), mouth opening, hand grip strength, range of motion (ROM), functional ability of upper limbs (DASH questionnaire and Cochin hand function scale-CHFS), 6-minute walk test (6MWT), and quality of life (SF-36 questionnaire). Linear regression models with random effects and Spearman's test were used for statistical analysis.

RESULTS

At 6 and 12 months after AHSCT, respectively, we observed significant improvement of mRSS (p < 0.01 and p < 0.01), mouth opening (p = 0.02 and p < 0.01), hand function (DASH, p < 0.01 and p < 0.01; CHFS, p < 0.01 and p < 0.01; strength, p < 0.01 and p < 0.01), physical capacity (6MWT, p = 0.02 and p = 0.03) and physical (p < 0.01 and p < 0.01) and mental (ns and p = 0.02) component scores of SF-36. At 12 months after AHSCT, ROM measurements improved (p < 0.05) in five out of six evaluated joints in both hands, compared to baseline. Correlation was significant between physical capacity and quality of life (R = 0.62; p < 0.01), between DASH and quality of life (R = -0.48; p = 0.03), and between skin involvement and wrist ROM measures (dominant hand, R = -0.65, p < 0.01; non-dominant hand, R = -0.59; p < 0.01).

CONCLUSIONS

AHSCT enhances the functional status of SSc patients in the first year of follow-up, significantly improving hand function, physical capacity and quality of life. These results are interpreted as positive outcomes of AHSCT for SSc.

Scleroderma renal crisis: a review for emergency physicians

Scleroderma renal crisis (SRC) remains a high-risk clinical presentation, and many patients require emergency department (ED) management for complications and stabilization. This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of SRC. While SRC remains a rare clinical presentation, surveillance data suggest an overall incidence between 4 and 6% of patients with scleroderma. The diagnostic criteria for SRC include a new onset blood pressure > 150/85 mm Hg OR increase ≥ 20 mm Hg from baseline systolic blood pressure, along with a decline in renal function, defined as an increase serum creatinine of ≥ 10% and supportive features. There are many risk factors for SRC, including diffuse and rapidly progressive skin thickening, palpable tendon friction rubs, and new anemia or cardiac events. Critical patients should be evaluated in the resuscitation bay, and consultation with the nephrology team for appropriate patients improves patient outcomes.

Impact of EUSTAR standardized training on accuracy of modified Rodnan skin score in patients with systemic sclerosis

OBJECTIVES

To investigate the impact of European Scleroderma Trials and Research (EUSTAR) standardized training on the accuracy of modified Rodnan skin score (mRSS) in patients with systemic sclerosis (SSc).

METHODS

Eight SSc patients (four diffuse, four limited) and 10 physicians (4 fellows, 6 professors) were included. Gold-standard mRSS was performed by a senior instructor. Training comprised a video presentation and a live demonstration. Each physician performed mRSS with no clinical information in all patients: (a) before training; (b) after video session; and (c) after live demonstration. Primary outcome was the change in scoring accuracy, which was defined as the difference from the gold-standard skin score, as analyzed using a linear mixed model.

RESULTS

Mean (standard deviation) difference from the gold-standard score in all measurements by participants before the training was 7.7 (9.5). Completion of training significantly enhanced mRSS accuracy (adjusted β = -7.61; 95% CI: -11.91 to -3.32). This was largely attributable to the video presentation (adjusted β = -5.47; -9.16 to -1.78), although the live demonstration was associated with numerical reduction in the difference from the gold-standard score (adjusted β = -2.15; -5.84 to 1.55). Effect of training was prominent in fellows whereas professors showed an increase in the difference from gold-standard score after training (P value for interaction <0.001). The intraclass correlation coefficient for physician skin scores was acceptable. However, no significant change was observed after training.

CONCLUSION

New EUSTAR standardized mRSS training significantly enhanced mRSS accuracy, especially in participant with less previous experience in skin scoring.

Oxidative/nitrative stress in the pathogenesis of systemic sclerosis: are antioxidants beneficial?

Systemic sclerosis (SSc) is a multisystem autoimmune disease: characterised from the clinical side by progressive vasculopathy and fibrosis of the skin and different organs and from the biochemical side by fibroblast deregulation with excessive production of collagen and increased expression of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4). The latter contributes to an overproduction of reactive oxygen species that through an autocrine loop maintains NOX4 in a state of activation. Reactive oxygen and nitrogen species are implicated in the origin and perpetuation of several clinical manifestations of SSc having vascular damage in common; attempts to dampen oxidative and nitrative stress through different agents with antioxidant properties have not translated into a sustained clinical benefit. Objective of this narrative review is to describe the origin and clinical implications of oxidative and nitrative stress in SSc, with particular focus on the central role of NOX4 and its interactions, to re-evaluate the antioxidant approaches so far used to limit disease progression, to appraise the complexity of antioxidant treatment and to touch on novel pathways elements of which may represent specific treatment targets in the not so distant future.

Assessment of skin involvement in systemic sclerosis

Skin involvement in SSc is an important marker of disease activity, severity and prognosis, making the assessment of skin a key issue in SSc clinical research. We reviewed the published data assessing skin involvement in clinical trials and summarized the major conclusions important in SSc clinical research. A systematic literature review identified randomized controlled trials using skin outcomes in SSc. Analysis examined the validity of the different skin measures based on literature findings. Twenty-two randomized controlled trials were found. The average study duration was 10.2 (s.d. 4.5) months, mean (s.d.) sample size 32.4 (32.6) and 26.7 (27.8) in intervention and control arms, respectively. The 17-site modified Rodnan skin score is a fully validated primary outcome measure in diffuse cutaneous SSc. Skin histology seems to be an appropriate method for evaluation of skin thickness. These findings have important implications for clinical trial design targeting skin involvement in SSc.

Targeted Therapy in Systemic Sclerosis

Targeted therapies use an understanding of the pathophysiology of a disease in an individual patient. Although targeted therapy for systemic sclerosis (SSc, scleroderma) has not yet reached the level of patient-specific treatments, recent developments in the understanding of the global pathophysiology of the disease have led to new treatments based on the cells and pathways that have been shown to be involved in the disease pathogenesis. The presence of a B cell signature in skin biopsies has led to the trial of rituximab, an anti-CD20 antibody, in SSc. The well-known properties of transforming growth factor (TGF)-β in promoting collagen synthesis and secretion has led to a small trial of fresolimumab, a human IgG4 monoclonal antibody capable of neutralizing TGF-β. Evidence supporting important roles for interleukin-6 in the pathogenesis of SSc have led to a large trial of tocilizumab in SSc. Soluble guanylate cyclase (sGC) is an enzyme that catalyzes the production of cyclic guanosine monophosphate (cGMP) upon binding of nitric oxide (NO) to the sGC molecule. Processes such as cell growth and proliferation are regulated by cGMP. Evidence that sGC may play a role in SSc has led to a trial of riociguat, a molecule that sensitizes sGC to endogenous NO. Tyrosine kinases (TKs) are involved in a wide variety of physiologic and pathological processes including vascular remodeling and fibrogenesis such as occurs in SSc. This has led to a trial of nintedanib, a next-generation tyrosine-kinase (TK) inhibitor which targets multiple TKs, in SSc.

Summed and Weighted Summary Scores for the Medsger Disease Severity Scale Compared with the Physician’s Global Assessment of Disease Severity in Systemic Sclerosis

Objective.

To develop a weighted summary score for the Medsger Disease Severity Scale (DSS) and to compare its measurement properties with those of a summed DSS score and a physician’s global assessment (PGA) of severity score in systemic sclerosis (SSc).

Methods.

Data from 875 patients with SSc enrolled in a multisite observational research cohort were extracted from a central database. Item response theory was used to estimate weights for the DSS weighted score. Intraclass correlation coefficients (ICC) and convergent, discriminative, and predictive validity of the 3 summary measures in relation to patient-reported outcomes (PRO) and mortality were compared.

Results.

Mean PGA was 2.69 (SD 2.16, range 0–10), mean DSS summed score was 8.60 (SD 4.02, range 0–36), and mean DSS weighted score was 8.11 (SD 4.05, range 0–36). ICC were similar for all 3 measures [PGA 6.9%, 95% credible intervals (CrI) 2.1–16.2; DSS summed score 2.5%, 95% CrI 0.4–6.7; DSS weighted score 2.0%, 95% CrI 0.1–5.6]. Convergent and discriminative validity of the 3 measures for PRO were largely similar. In Cox proportional hazards models adjusting for age and sex, the 3 measures had similar predictive ability for mortality (adjusted R2 13.9% for PGA, 12.3% for DSS summed score, and 10.7% DSS weighted score).

Conclusion.

The 3 summary scores appear valid and perform similarly. However, there were some concerns with the weights computed for individual DSS scales, with unexpected low weights attributed to lung, heart, and kidney, leading the PGA to be the preferred measure at this time. Further work refining the DSS could improve the measurement properties of the DSS summary scores.

Correlations between changes in cytokines and clinical outcomes for early phase (proof of concept) trials in active diffuse systemic sclerosis using data from an imatinib study

OBJECTIVE

Data from a small study testing imatinib to treat SSc were used to determine if cytokine changes were related to differences in clinical parameters to model future early phase trials pairing cytokine changes and clinical parameters.

METHODS

Plasma and punch skin biopsy specimens collected at baseline and 6 months were analysed for levels of 26 fibrotic and inflammatory cytokines using multiplexed immunoassays and ELISA. Seven of nine patients on active treatment had paired data. Biopsies were biopulverized and standardized to protein levels in the tissue homogenate. Plasma was frozen at -80°C and analysed using multiplexed immunoassays or ELISAs standardized to CRP. Correlations between fold changes in cytokines and differences in clinical parameters (skin score, physician and patient global assessments and HAQ) were performed. P < 0.01 was considered significant.

RESULTS

After 6 months of imatinib treatment, plasma levels of soluble vascular cell adhesion molecule 1 decreased significantly (P < 0.001), while tissue levels of soluble intercellular adhesion molecule 1 increased (P < 0.01). Some significant correlations between fold changes in certain plasma fibrotic and inflammatory cytokines and changes in clinical parameters after 6 months of treatment were found: patient global scores and IL-13 (r = 0.964, P < 0.0001); ESR and IL-12p70 (r = -0.903, P < 0.01); in tissue samples, patient global score and soluble E-selectin (r = 0.913, P < 0.01); and physician global score with sCD40L (r = -0.883, P < 0.01).

CONCLUSION

Some serum and tissue cytokines may have a role in early phase clinical trials of SSc, correlating with changes in clinical parameters. Serum and tissue samples could be analysed in early phase trials to determine whether they support the clinical observations.

TRIAL REGISTRATION

http://clinicaltrials.gov/show/NCT01545427.

Are scores on English and French versions of the PHQ-9 comparable? An assessment of differential item functioning

Background

Medical research increasingly utilizes patient-reported outcome measures administered and scored in different languages. In order to pool or compare outcomes from different language versions, instruments should be measurement equivalent across linguistic groups. The objective of this study was to examine the cross-language measurement equivalence of the Patient Health Questionnaire-9 (PHQ-9) between English- and French-speaking Canadian patients with systemic sclerosis (SSc).

Methods

The sample consisted of 739 English- and 221 French-speaking SSc patients. Multiple-Indicator Multiple-Cause (MIMIC) modeling was used to identify items displaying possible differential item functioning (DIF).

Results

A one-factor model for the PHQ-9 fit the data well in both English- and French-speaking samples. Statistically significant DIF was found for 3 of 9 items on the PHQ-9. However, the overall estimate in depression latent scores between English- and French-speaking respondents was not influenced substantively by DIF.

Conclusions

Although there were several PHQ-9 items with evidence of minor DIF, there was no evidence that these differences influenced overall scores meaningfully. The PHQ-9 can reasonably be used without adjustment in Canadian English- and French-speaking samples. Analyses assessing measurement equivalence should be routinely conducted prior to pooling data from English and French versions of patient-reported outcome measures.

Effect and safety of mycophenolate mofetil or sodium in systemic sclerosis-associated interstitial lung disease: a meta-analysis

Background. Interstitial lung disease (ILD) is the most common complication of systemic sclerosis (SSc) with treatment ineffective. Objective: The aim of this meta-analysis was to provide an estimate of the safety and efficacy profile of Mycophenolate Mofetil (MMF) or sodium (MMS) in SSc-ILD patients. Materials and Methods. All studies were reviewed systematically. The main end-points were safety and efficacy profile as estimated by forced vital capacity (FVC)% and diffusion capacity of the lung for carbon monoxide (DL_CO)% of the predicted normal value (%pred.) before and after treatment in patients with SSc-ILD. Quality assessment and data extraction were performed independently by two reviewers. Results. Seventeen studies were reviewed systematically. Six studies, one prospective, were eligible for analysis encompassing 69 patients, including 10 subjects from our, yet unpublished, retrospective study. There was no statistically significant difference in both efficacy outcomes of interest, including FVC% pred. (weighted mean difference 1.48, 95% confidence interval (CI): −2.77 to 5.72, P = 0.49) and DL_CO % pred. (weighted mean difference −0.83, 95% CI: −4.75 to 3.09, P = 0.93). No cases of clinically significant side effects were documented. Conclusions. Meta-analysis data suggest that MMF is a safe therapeutic modality which was associated with functional stabilization in patients with SSc-ILD.

Evaluating hand in systemic sclerosis

Articular symptoms are common in SSc and joint pain is a frequent presenting feature of this disease. Hand involvement is often the first clinical manifestation of SSc and could be resulted from fibrosis or synovitis or an overlap syndrome with rheumatoid arthritis (RA); though, the latter is a controversy in practice. To define the clues when identifying the nature of the hand arthropathy in SSc. In order to determine the hand arthropathy, serological tests, hand radiography, finger-to-palm (FTP) distance and other clinical features, disease activity and functional scoring parameters were assessed. Twenty-eight consecutive SSc patients and 43 controls (21 rheumatoid arthritis and 22 healthy controls) were included. Radiographic findings in SSc patients were: Erosions 25%, joint space narrowing 17.9%, arthritis 10.7%, radiological demineralisation 42.9%, acro-osteolysis 25%, flexion contracture 28.6% and calcinosis 17.9%. Anti-CCP antibody and RF positivity were as follows: In SSc group: 3 (11%) and 7 patients (25%); In RA group: 13 (62%) and 19 patients (90.5%); In healthy control group: 1 (4%) and 3 persons (13.6%), respectively. Two patients (7.14%) were regarded as RA overlap, whom both had positive RF and positive anti-CCP results and their radiographs revealed arthritis. Seventeen patients (61%) were regarded as SSc arthropathy; all were negative for RF and anti-CCP but revealed nonarthritic radiological findings. (Among them, only one patient had positive anti-CCP result). The remainder (9 patients) had no radiological or serological finding positive for arthropathy. Arthritis was found to have correlation with heart involvement and FTP was correlated with lung involvement. Hand involvement in SSc is a challenge in rheumatology practice; Radiographic testing when evaluated with RF and anti-CCP will be a helpful tool to discriminate SSc arthropathy from RA-SSc overlap. Hand arthropathy should increase the interest in the serious internal organ involvements of SSc.

Homocysteine and copper interact to promote type 5 phosphodiesterase expression in rabbit cavernosal smooth muscle cells

AIM

To study the effects of homocysteine and copper on type 5 phosphodiesterase (PDE5) expression in cavernosal vascular smooth muscle cells (CVSMCs) and to investigate superoxide (O(2)(.-)) derived from nicotinamide adenine dinucleotide phosphate oxidase as homocysteine and copper generate O(2)(.-), and O(2)(.-) upregulates PDE5 expression.

METHODS

CVSMCs derived from rabbit penis were incubated with homocysteine or copper chloride with or without superoxide dismutase (SOD), catalase, sildenafil citrate, or apocynin (nicotinamide adenine dinucleotide phosphate inhibitor) for 16 h. The expression of PDE5 and of glyceraldehyde-3-phosphate dehydrogenase (internal standard) was assessed using Western blot analysis. In parallel, O(2)(.-) was measured spectrophotometrically.

RESULTS

CuCl(2) alone (up to 10 micromol/L) and homocysteine alone (up to 100 micromol/L) had no effect on O(2)(.-) formation in CVSMCs compared to controls. In combination, however, homocysteine and CuCl(2) markedly increased O(2)(.-) formation, an effect blocked by SOD, catalase, apocynin, and sildenafil (1 micromol/L) when co-incubated over the same time course. PDE5 expression was also significantly increased in CVSMCs incubated with homocysteine and CuCl(2), compared to controls. This effect was also negated by 16-h co-incubation with SOD, catalase, apocynin and sildenafil.

CONCLUSION

This represents a novel pathogenic mechanism underlying ED, and indicates that the therapeutic actions of prolonged sildenafil use are mediated in part through inhibition of this pathway.

Orally administered penicillamine is a potent inhibitor of neointimal and medial thickening in porcine saphenous vein–carotid artery interposition grafts

OBJECTIVE

In patients who have undergone coronary artery bypass grafting, blood copper levels are elevated for 6 weeks after surgery. Copper is an established risk factor for cardiovascular disease and atherogenesis and promotes oxidative stress, lipid oxidation, cell proliferation, and matrix formation, all components of vein graft disease. This project therefore examined the effect of the copper chelator penicillamine on saphenous vein graft thickening in a pig model.

METHODS

Saphenous vein-carotid artery interposition grafts were carried out in Landrace pigs. Penicillamine (10 mg/kg once daily, n = 8) was administered orally incorporated into small amounts of mashed potato for 1 month (n = 8 controls). Vein grafts were then excised and fixed at 100 mm Hg, histologic sections were prepared, and morphometry and measurement of proliferating cell nuclear antigen count were carried out. In vitro studies on the effect of copper or penicillamine on human vascular smooth muscle cell replication was carried out with bromodeoxyuridine incorporation.

RESULTS

Administration of penicillamine had a potent inhibitory effect on both neointimal and medial thickness and proliferating cell nuclear antigen count but elicited a marked increase in luminal area and reduced serum copper concentrations. In vitro, copper augmented vascular smooth muscle cell proliferation, an effect blocked by penicillamine. Penicillamine alone also inhibited in vitro vascular smooth muscle cell replication.

CONCLUSION

The administration of penicillamine reduces vein graft thickening and promotes positive remodeling through negation of copper-induced cell proliferation. Copper chelators may therefore be therapeutically useful in preventing late vein graft failure in patients undergoing reconstructive arterial surgery.

Update on Connective Tissue Diseases in Dermatology

Recent advances in understanding the pathogenesis of autoimmune diseases, including lupus erythematosus, dermatomyositis, and scleroderma, have allowed for reorganization of the classification of these disorders. With these novel stratifications, early identification of rheumatic skin diseases with systemic implications and consistency in designing and executing therapeutic trials will be enhanced. This review will provide a compilation of updates on epidemiology, pathology, evaluation, and classification with a predominant focus on therapeutics, reflecting the growth is this area.

[Treatment of systemic sclerosis]

Treatment of systemic sclerosis is based upon 3 types of medications modifiers of disease: drugs which prevent vascular damage, antifibrotric agents, and immunomodulators and immunosupressors. Drugs that prevent vascular damage such as: calcium antagonists, prostaglandins analogues, receptors of endothelin blockers (bosentan), inhibitors of angiotensin converting enzyme, receptors of angiotensin antagonists and inhibitors of 5'-phosphodiesterase have been successful in treating the Raynaud's phenomenon, renal crisis and pulmonary arterial hypertension. In contrast, the results of treatment of fibrosis are discouraging and the D-penicilamine continues being a matter of controversy. The immunosupressor therapy with cyclophosphamide and the transplant of hematopoietic cells, may be beneficial. The knowledge of the pathogenesis of systemic sclerosis to molecular level will lead to new treatment strategies.

Mechanisms and consequences of fibrosis in systemic sclerosis

Systemic sclerosis (SSc), also known as scleroderma, is a complex connective tissue disease that is associated with a high mortality and is challenging to treat because of its clinical heterogeneity and a lack of effective antifibrotic therapies. SSc has vascular, immunologic and fibrotic components that are pathologically interconnected. A growing understanding of the molecular and cellular mechanisms that underlie SSc pathogenesis provides logical and novel approaches to treatment. At present most therapies are organ-based. Vascular and inflammatory components of the disease can also be treated, but effective antifibrotic therapies are lacking. A number of key molecular mediators have the potential to alter immune-cell, vascular and fibrotic processes and these mediators, which include transforming growth factor-beta isoforms, endothelin-1, connective-tissue growth factor, chemokines and members of the interleukin family, are attractive targets for therapeutic modulation. Key mediators can be blocked using antibodies, soluble receptors, endogenous inhibitors or small-molecule antagonists of ligands, receptors or signaling intermediates. Overall, this is an exciting time for new therapies in SSc and advances are being made in synchrony with an improved understanding of the molecular and biochemical basis of the disease.

Penicillamine administration reverses the inhibitory effect of hyperhomocysteinaemia on endothelium-dependent relaxation in the corpus cavernosum in the rabbit

OBJECTIVE

To elucidate the role of copper in mediating the impact of homocysteine on vasculogenic erectile dysfunction (VED), by investigating the effect of dietary supplementation with the copper-chelator penicillamine to rabbits rendered hyperhomocysteinaemic (HHC) with a methionine-rich diet, as a raised plasma level of homocysteine might be a risk factor for VED.

MATERIALS AND METHODS

Homocysteine inhibits the nitric oxide (NO)-dependent relaxation of the corpus cavernosum (CC), an effect which appears to be mediated via the generation of superoxide (O2*-), and H2O2. Copper is a catalyst for the generation of H2O2 in the presence of homocysteine and in the presence of copper, H2O2 undergoes reactions resulting in the generation of O2*-, which reacts with NO to produce peroxynitrite (ONOO-), thereby reducing the bioavailability of NO and impairing NO-mediated relaxation of CC. Smooth muscle strips from CC were obtained from two groups of adult New Zealand White rabbits, one rendered HHC with a diet supplemented with methionine (group 1) and another HHC group that had additional dietary supplementation with penicillamine (group 2). Tissue O2*- levels were measured in each group. After pre-contraction with phenylephrine, relaxation responses of CC strips to carbachol were also assessed in both groups.

RESULTS

Methionine supplementation led to profound HHC in all rabbits. Penicillamine in group 2 reduced the total plasma Cu2+ compared to group 1. There was a markedly lower carbachol-stimulated relaxation of CC from HHC rabbits in group 1, with a mean (sem) maximum relaxation of 37 (4)% (six samples), than in group 2, at 58 (6)%.

CONCLUSION

These data show that elevated levels in vivo of homocysteine in the rabbit markedly impair NO-dependent relaxation of the CC. Furthermore, this effect appears to be augmented by copper. Further clinical studies on homocysteine and copper status in patients with VED are warranted.

Penicillamine administration reverses the inhibitory effect of hyperhomocysteinaemia on endothelium-dependent relaxation and superoxide formation in the aorta of the rabbit

Although hyperhomocysteinaemia is a risk factor for cardiovascular disease, the mechanisms underlying this association have not been elucidated. It has been demonstrated, however, that copper augments the inhibitory effect of homocysteine on nitric oxide (NO)-mediated relaxation of the rat aorta through increased superoxide formation, which reacts with NO thereby reducing the bioavailability of NO. Since it follows that the administration of a copper chelator may blunt the pathogenic impact of hyperhomocysteinaemia, in vivo, the effect of penicillamine administration on NO-dependent relaxation and superoxide formation in the aortae of hyperhomocysteinaemic rabbits was studied. New Zealand White rabbits were fed a methionine-rich (20 g/kg chow) diet for 1 month+/-penicillamine administered orally (10 mg/kg/day) and aortic relaxation elicited with acetylcholine and superoxide measured. The role of NADPH oxidase was also studied using a range of inhibitors and western analysis of gp47(phox) (a catalytic subunit of NADPH oxidase). The methionine-rich diet markedly increased plasma total homocysteine levels. In hyperhomocysteinaemic rabbits there was a marked reduction of acetylcholine-stimulated relaxation and an increase in superoxide formation that were both inhibited with superoxide dismutase and apocynin, an NADPH oxidase inhibitor. Gp47(phox) expression was also increased in aortae from methionine fed rabbits. Penicillamine administration significantly reduced plasma total copper in methionine-fed rabbits compared to controls. Impaired acetylcholine-stimulated relaxation, increased superoxide formation and increased gp47(phox) expression in aortae from methionine-fed rabbits was reversed by penicillamine administration. These data indicate that hyperhomocysteinaemia augments the formation of arterial superoxide through an increase in NADPH oxidase expression/activity which in turn reduces NO bioavailability. Since these effects were reversed by penicillamine, these data consolidate the hypothesis that copper plays a role in mediating homocysteine-induced vasculopathy.

Targeted therapy comes of age in scleroderma

Systemic sclerosis (SSc, also known as scleroderma) has the highest case-specific mortality among the rheumatic diseases; however, advances in understanding of pathogenesis and an appreciation of the clinical heterogeneity of this disease, together with therapeutic advances in other areas, have raised the possibility of substantial improvements in its management. Key areas of advance include the development of clinical and laboratory methods for early detection of complications and the integration of vascular, immunomodulatory and antifibrotic therapies. Disease models have facilitated the identification of key mediators or processes that could be targeted therapeutically and have provided a platform for preclinical testing of novel candidate therapies. This review will consider current clinical aspects of SSc and the emergence of targeted therapy that is linked to key pathogenic processes or that targets pivotal mediators.