Serum and urine free light chains measurements in patients with systemic sclerosis: novel biomarkers for disease activity.

Circulating free light chains (FLCs), considered biomarkers of B cell activity, are frequently elevated in patients affected by systemic inflammatory autoimmune diseases. As the systemic sclerosis (SSc) clinical course can be variable, this study is aimed at evaluating FLCs levels in affected individuals as biomarkers of disease activity. We assessed FLC levels in serum and urine of 72 SSc patients and 30 healthy controls (HC). Results were analyzed in comparison with overall clinical and laboratory findings, disease activity index (DAI) and disease severity scale (DSS). SSc patients displayed increased levels of κ and λ FLC in serum significantly higher than HC (p = 0.0001) alongside the mean values of free κ/λ ratio and κ + λ sum (p = 0.0001). SSc patients showed increased free κ in urine with a κ/λ higher than HC (p = 0.0001). SSc patients with increased κ + λ in serum showed that erythro-sedimentation rate (p = 0.034), C-reactive protein (p = 0.003), DAI (p = 0.024) and DSS (p = 0.015) were higher if compared to SSc patients with normal levels of FLC. A positive linear correlation was found between serum levels of free κ and DAI (r = 0.29, p = 0.014). In addition, SSc patients with increased free κ in urine had higher DAI (p = 0.048) than SSc patients with normal κ levels. Our results strengthen the role of serum FLC as useful biomarker in clinical practice to early diagnosis and monitor disease activity, showing for the first time that also urine FLC levels correlated with disease activity in SSc patients.

Urinary and plasma metabolite differences detected by HPLC-ESI-QTOF-MS in systemic sclerosis patients.

Systemic Sclerosis (SSc) is a chronic autoimmune disease whose origin and pathogenesis are not yet well known. Recent studies are allowing a better definition of the disease. However, few studies have been performed based on metabolomics. In this way, this study aims to find altered metabolites in SSc patients in order to improve their diagnosis, prognosis and treatment. For that, 59 SSc patients and 28 healthy volunteers participated in this study. Urine and plasma samples were analysed by a fingerprinting metabolomic approach based on HPLC-ESI-QTOF-MS. We observed larger differences in urine than plasma metabolites. The main deregulated metabolic families in urine were acylcarnitines, acylglycines and metabolites derived from amino acids, specifically from proline, histidine and glutamine. These results indicate perturbations in fatty acid beta oxidation and amino acid pathways in scleroderma patients. On the other hand, the main plasma biomarker candidate was 2-arachidonoylglycerol, which is involved in the endocannabinoid system with potential implications in the induction and propagation of systemic sclerosis and autoimmunity.

Association Between Exposure to Heavy Metals and Systemic Sclerosis: the Levels of Al, Cd, Hg, and Pb in Blood and Urine of Patients.

Systemic sclerosis (SSc) is a multisystem connective tissue disease; exogenous factors-including heavy metals-may have a role in the disease pathogenesis. In this context, a study on the quantification of Al, Cd, Hg, and Pb in blood and urine of 27 SSc patients and 30 controls was carried out. Main findings were that Al was significantly depleted in blood and increased in urine of SSc patients respect to controls; and Pb was found slightly increased in blood and significantly decreased in SSc group. In addition, higher Hg levels in urine were found in SSc subjects with the higher severity of the disease. Females showed the most marked differences in the levels of blood Al, blood Pb, and urine Cd between patients and controls. Smoking, hobby, ingestion of contaminated food, job exposure may contribute to the bodily levels of Al, Hg, Pb in SSc patients. The results indicated that low, chronic, and multiple exposures to heavy metals-also through habits, diet, and environment-may influence the risk for SSc.

Soluble CD163 as a Potential Biomarker in Systemic Sclerosis.

OBJECTIVE: To evaluate the performance of serum and urinary sCD163 concentrations as possible biomarker in systemic sclerosis (SSc). METHODS: Urine and serum samples were obtained from SSc patients and age- and sex-matched controls. Serum and urinary sCD163 concentrations were measured by commercially available ELISA kit. SSc patients were assessed following international guidelines. Cross-sectional analyses were performed. RESULTS: Two hundred and three SSc patients were included. The control group consisted of 47 age- and sex-matched patients having noninflammatory diseases, mainly osteoporosis. Serum sCD163 levels were significantly higher in SSc patients compared with controls (mean ± SD: 529 ± 251 versus 385 ± 153 ng/mL; p < 0.001). Urinary sCD163 concentrations were higher in SSc patients than controls, but this did not reach significance (236 ± 498 versus 176 ± 173 ng/mg uCr; p = 0.580). The sCD163 concentrations were not associated with clinical, laboratory, and instrumental characteristics of SSc patients. CONCLUSION: To our knowledge, this is the first evaluation of both serum and urinary sCD163 levels in SSc. Our results show a significant difference for sera values that should be prioritized for further studies as compared to urinary measurements. Our results further support that the M2 macrophages/CD163 signaling system may play a role in the pathogenesis of SSc, although we could not identify a subset of SSc patients with higher concentrations.

Oxalate nephropathy in systemic sclerosis: Case series and review of the literature.

OBJECTIVE: To increase awareness of oxalate nephropathy as a cause of acute kidney injury (AKI) among systemic sclerosis patients with small intestinal dysmotility and malabsorption, and to prompt consideration of dietary modification and early treatment of predisposing causes of oxalate nephropathy in this population. METHODS: Two cases of biopsy-proven oxalate nephropathy were identified among systemic sclerosis patients in the course of direct clinical care. Subsequently, a retrospective search of the Johns Hopkins Pathology databases identified a third patient with systemic sclerosis who developed oxalate nephropathy. RESULTS: Among the three patients with qualifying biopsies, all three had systemic sclerosis with lower gastrointestinal involvement. All three presented with diarrhea, malabsorption, and AKI. In two of the three patients, diarrhea was present for at least 2 years before the development of AKI; in the third, incidental oxalate nephropathy was noted 3 years before she developed AKI and extensive oxalate nephropathy in the setting of a prolonged mycobacterium avium-intracellulare enteritis. In the first case, oxalate crystals were present by urinalysis months before diagnosis by biopsy; in the second, hyperoxaluria was diagnosed by urine collection immediately after; and in the third, oxalate crystals had been noted incidentally on post-transplant renal biopsy 3 years before the development of fulminant oxalate nephropathy. All three patients died within a year after diagnosis. CONCLUSIONS: Patients with systemic sclerosis and bowel dysmotility associated with chronic diarrhea and malabsorption may be at risk for an associated oxalate nephropathy. Regular screening of systemic sclerosis patients with small bowel malabsorption syndromes through routine urinalysis or 24-h urine oxalate collection, should be considered. Further studies defining the prevalence of this complication in systemic sclerosis, the benefit of dietary modification on hyperoxaluria, the effect of treating small intestinal bowel overgrowth with antibiotics, and the effectiveness of probiotics, calcium supplements, or magnesium supplements to prevent hyperoxaluria-associated renal disease in these patients, are warranted.

[Diagnostic value of the determination of angiogenic factors and cytokine composition parameters in the serum and urine of patients with scleroderma systematica].

AIM: To study the associations of the concentration of interleukins (IL) 1beta, 6, 8, 10, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha, vascular endothelial growth factor (VEGF) in the serum and urine with the clinical features of scleroderma systematica (SDS). SUBJECTS AND METHODS: The investigation enrolled 51 patients with a valid SDS diagnosis. The serum and urinary concentrations of interleukins, TNF-alpha, MCP-1, and VEGF were measured by solid-phase enzyme immunoassay. RESULTS: The patients with SDS were found to have higher serum and urine concentrations of proinflammatory cytokines and VEGF than in the comparison group. There were relationships between the levels of VEGF and proinflammatory cytokines and the disease duration, clinical forms, and clinical manifestation of SDS. CONCLUSION: Higher serum VEGF levels in patients with SDS may be used to estimate the magnitude of endothelial dysfunction. Estimation of serum IL-6 concentrations may be employed to determine the degree of sclerosis progression; that of MCP1 for the activity of fibrosing alveolitis. Quantitative analysis of urinary IL-6, IL-8, and VEGF levels in patients with SDS may be used to evaluate tubulointerstitial inflammation and to predict the development of interstitial fibrosis.

High DNA oxidative damage in systemic sclerosis.

OBJECTIVE: Several lines of evidence suggest that the generation of reactive oxygen species (ROS) is of major importance in the pathogenesis of SSc. Protein and lipid damage have previously been demonstrated, but scarce data are available on oxidative damage to DNA. In patients with SSc, we evaluated levels of 8-hydroxy-2'-deoxyguanosine (8-oxodG), the main validated biomarker of endogenous oxidative damage to DNA, compared to levels of F2-isoprostane, a product of free radical-mediated peroxidation of arachidonic acid. METHODS: Urinary levels of 8-oxodG and 8-isoprostaglandin-F(2α) (8-iso-PGF(2α)) were determined by competitive ELISA method in consecutive SSc patients and controls matched for age and sex. RESULTS: We included 80 unrelated SSc patients (72 women, mean age 56 ± 11 yrs) and 39 controls (33 women, mean age 64 ± 8 yrs). Urinary levels of 8-oxodG/creat and 8-iso-PGF(2α)/creat in SSc patients were found to be higher than in controls (6.5 ng/mg vs 3.7 ng/mg, p = 0.0001; and 11.4 ng/mg vs 4.2 ng/mg, p < 0.0001). In multivariate analysis, 8-oxodG levels were associated with the presence of pulmonary fibrosis on computerized tomography scan, decreased forced vital capacity, and decreased DLCO/alveolar volume. In patients with the diffuse cutaneous subset, a modified Rodnan skin score > 14 was independently associated with 8-oxodG levels. In SSc, 8-oxodG and 8-iso-PGF(2α) values were correlated (r = 0.32; p = 0.005). CONCLUSION: Our study confirmed marked oxidative stress in SSc. We also found increased values of 8-oxodG in SSc patients and a relevant association with a fibrotic phenotype. The predictive value of this marker and its potential influence on fibrotic disturbances remain to be determined.

Intermediate molecular weight proteinuria and albuminuria identify scleroderma patients with increased morbidity.

BACKGROUND: Renal involvement and systemic vascular damage have been shown to significantly affect prognosis in systemic sclerosis (SSc). However, it is often difficult to assess damage to the renal and systemic vasculature in SSc patients. METHODS: Using detailed urinary protein analysis we sought to detect scleroderma renal disease at an early stage and to assess systemic vasculopathy due to SSc. We examined 80 patients with SSc as well as 18 healthy control subjects using urinary protein analysis including determination of urinary albumin excretion rate and urinary total protein excretion as well as urinary polyacrylamide gel electrophoresis. RESULTS: Albuminuria was found in 25% (20/80) of the SSc patients (2.5% macroalbuminuria, 22.5% microalbuminuria), increased total protein excretion in 17.5% (14/80), and intermediate molecular weight proteinuria (IMWP) as determined by urine electrophoresis in 31.3% (25/80). None of these abnormalities was found in the control group (0/18). Presence of IMWP correlated with the diffuse type of SSc (p < 0.01), gastrointestinal involvement (p < 0.05) and increased systolic blood pressure (p < 0.01). Increased total protein excretion was found to correlate with pulmonary involvement (p < 0.05). Albuminuria was associated with prolonged duration of the disease (> 4 years) (p < 0.05) and increased systolic blood pressure (p < 0.01). CONCLUSIONS: Leakage of proteins into the urine in patients with SSc appears to indicate not only renal involvement but also systemic vasculopathy which is associated with increased morbidity. Patients with SSc should be regularly examined using sensitive urinary protein tests such as albumin assays or urine electrophoresis, to detect kidney involvement at an early stage.

Postocclusive reactive hyperemia inversely correlates with urinary 15-F2t-isoprostane levels in systemic sclerosis.

Microvascular dysfunction and increased oxidative stress are major hallmarks of the systemic sclerosis disease process. The primary objective of this study was to test whether there is a link between peak postocclusive hyperemia and urinary levels of the F2-isoprostane 15-F2t-IsoP (8-iso-PGF2alpha) in patients suffering from systemic sclerosis. We enrolled 43 patients suffering from systemic sclerosis, 33 patients with primary Raynaud's phenomenon (RP), and 25 healthy volunteers. Microvascular function was assessed using the postocclusive hyperemia monitored by laser Doppler flowmetry. Endothelium-independent response was monitored after 0.4 mg sublingual nitroglycerin. Oxidative stress status was assessed by urinary levels of the F2-isoprostane 15-F2t-IsoP using GC-MS. The peak postocclusive vascular conductance was altered in subjects with systemic sclerosis and primary RP compared to controls (respectively 28 (7-48), 30 (13-48), and 39.9 (13-63) mV/mm Hg, p = 0.01). F2-isoprostanes were increased in the systemic sclerosis group compared to primary Raynaud's phenomenon and healthy controls (respectively 230 (155-387), 182 (101-284), and 207 (109-291) pg/mg, p = 0.006). In patients suffering from systemic sclerosis, there was a significant inverse correlation between F2-isoprostanes and postocclusive hyperemia, expressed as raw data (R = -0.45, p = 0.007) or as an increase over baseline (R = -0.28, p = 0.04). Conversely, no correlation was found with the nitroglycerin response. In conclusion, we provide evidence that there is an inverse correlation between postocclusive hyperemia and urinary F2-isoprostane levels in patients suffering from systemic sclerosis. Whether oxygen free radicals initiate the vascular dysfunction or whether there is an initial trigger that initiates both processes will need to be further clarified in future studies.

Levels of F2-isoprostanes in systemic sclerosis: correlation with clinical features.

OBJECTIVE: Oxidative stress may be one of the important complex pathogenetic mechanisms that lead to damage in scleroderma; free radicals may provoke endothelial injury, fibroblast proliferation and fragmentation of autoantigens favouring induction of autoantibodies. The present study investigates the oxidant status in scleroderma patients by measuring the urinary concentration of 8-isoprostaglandin-F2alpha, an F2-isoprostane, and a product of free radical-mediated peroxidation of arachidonic acid. METHODS: Forty-three scleroderma patients (42 women and 1 man, mean age 54.1 yr, mean disease duration 9.0 yr) underwent clinical evaluation and instrumental investigations in order to assess skin, vascular, lung and heart involvement. Von Willebrand factor was evaluated as marker of vascular dysfunction in 36 out of the 43 cases. The urinary level of 8-isoprostaglandin-F2alpha was measured in all scleroderma patients and in the 43 age- and sex-matched healthy controls. RESULTS: Urinary levels of 8-isoprostaglandin-F2alpha were higher in scleroderma patients than in the healthy control group (341.7 vs 147.6 pg/mg creatinine; P < 0.001). Values of 8-isoprostaglandin-F2alpha were strongly correlated with the nailfold videocapillaroscopy pattern and lung involvement (P = 0.002 and 0.003, respectively), showing increasing levels with the progression of pulmonary severity. Correlation between 8-isoprostaglandin-F2alpha level and von Willebrand factor narrowly failed to reach statistical significance (P = 0.05). There was no correlation between 8-isoprostaglandin-F2alpha concentration and disease activity, vascular, skin and heart involvement, disease pattern or autoantibody profile. CONCLUSIONS: Our study further supports the role of oxidant stress in the pathogenesis of scleroderma, showing a strong correlation between a marker of free radical damage with both the severity of lung involvement and the videocapillaroscopic patterns.

Effects of short-term treatment with vitamin E in systemic sclerosis: a double blind, randomized, controlled clinical trial of efficacy based on urinary isoprostane measurement.

This double blind randomized controlled trial was designed to investigate whether short-term vitamin E treatment at doses of 500 and 1000 mg/day, compared to placebo, decreased urinary F(2)-isoprostanes and improved the microvascular perfusion after cold exposure in patients suffering from SSc. Thirty-three eligible patients were randomly assigned in a 1.3:1:1 ratio to receive placebo, vitamin E 500 mg, or vitamin E 1000 mg daily for 3 weeks. Clinical examination, analysis of plasma vitamin E, urinary F(2)-isoprostane levels and a whole body cooling test were performed at baseline and after a 3-week period of treatment. Urinary 15-F(2t)-IsoP levels and cutaneous blood flow variation in response to cold did not significantly differ before versus after treatment in any group. Furthermore, no difference was found between groups after 3 weeks of treatment. We show that 3-week vitamin E treatment at doses of 500 or 1000 mg/day neither decreases the basal rate of lipid peroxidation nor improves microvascular perfusion after cold exposure. These data does not support the need for phase III clinical trials to test efficacy of vitamin E in SSc.

Increased urinary F2-isoprostanes in systemic sclerosis, but not in primary Raynaud's phenomenon: effect of cold exposure.

OBJECTIVE: F2-isoprostanes are free radical-dependent arachidonic acid metabolites that are used as clinical markers of lipid peroxidation in systemic sclerosis (SSc) and other microvascular diseases. The objectives of this study were to determine whether the basal urinary levels of F2-isoprostane in SSc patients differ from those in patients with primary Raynaud's phenomenon (RP) and to investigate whether F2-isoprostane formation correlates with the cutaneous microvascular perfusion decrease following cold exposure in SSc patients, patients with primary RP, and healthy controls. METHODS: Eleven women with RP secondary to SSc, 11 women with primary RP, and 11 healthy women were exposed to decreasing room temperature, from 25 degrees C to 15 degrees C, for 40 minutes. Urine samples were obtained before and after the test for gas chromatography/electronic impact mass spectrometry quantification of 15-F(2t)-isoprostane (15-F(2t)-IsoP; also called isoprostaglandin F(2alpha) type III). Cutaneous blood flow was monitored using a laser Doppler perfusion imager. RESULTS: The mean +/- SEM urinary 15-F(2t)-IsoP levels at baseline in SSc patients (178 +/- 32 pmoles/mmole of creatinine) were 1.9 times higher than those in healthy controls (95 +/- 11 pmoles/mmole of creatinine) and 1.7 times higher than those in patients with primary RP (107 +/- 19 pmoles/mmole of creatinine) (P < 0.05 for controls and patients with primary RP versus SSc patients). No significant correlation was found between basal urinary 15-F(2t)-IsoP levels and the temperature or cutaneous blood flow decrease in response to the whole-body cooling. Furthermore, the 15-F(2t)-IsoP response to the cooling test was not correlated with the cutaneous blood flow decrease. CONCLUSION: Lipid peroxidation is increased in SSc patients, but not in patients with primary RP. Cold exposure leads to a significant but small increase in 15-F(2t)-IsoP levels that is independent of the cutaneous blood flow decrease. F2-isoprostane quantification may be an interesting pharmacologic tool for monitoring responses to antioxidant treatment in SSc patients.

Enhanced in vivo lipid peroxidation in scleroderma spectrum disorders.

OBJECTIVE: A new family of prostaglandin F2 isomers called F2-isoprostanes, produced by free radical peroxidation of arachidonic acid, has recently been described in vivo. Its quantification has been suggested to be a reliable measure of oxidant injury in vivo. The purpose of this study was to investigate urinary F2-isoprostane formation as an index of lipid peroxidation in scleroderma spectrum disorders. METHODS: Urine samples were obtained from 52 patients with systemic sclerosis (SSc; n = 37) or undifferentiated connective tissue diseases (UCTD; n = 15) and from 20 healthy volunteers. Urinary isoprostaglandin F2alpha type III (iPF2alpha-III) and 11-dehydro thromboxane B2 (11-dehydroTXB2) concentrations were determined using enzyme immunoassays. RESULTS: The urinary concentration of iPF2alpha-III was approximately twice as high in patients (mean +/- SEM 229+/-16 pmoles/mmoles creatinine) as in controls (116+/-9 pmoles/mmoles creatinine) (P < 0.0001). However, the urinary concentration of iPF2alpha-III was not significantly different among patients with UCTD, limited SSc, and diffuse SSc (mean +/- SEM 221+/-27 versus 245+/-32 versus 220+/-25 pmoles/mmoles creatinine, respectively). No significant correlation was found between the urinary concentrations of iPF2alpha-III and 11-dehydroTXB2. CONCLUSION: This study provides evidence of enhanced lipid peroxidation in both SSc and UCTD, and suggests a rationale for antioxidant treatment of SSc. Formation of F2-isoprostanes has to be investigated as a means for the evaluation of such therapy.

Increased urinary pyridinoline cross-link compounds of collagen in patients with systemic sclerosis and Raynaud's phenomenon.

OBJECTIVE: To study concentration changes in collagen degradation markers in patients with diffuse and limited cutaneous systemic sclerosis and patients with scleroderma-related diseases. METHODS: Pyridinoline cross-link compounds were analysed in urine samples using high-performance liquid chromatography. Samples were analysed for pyridinoline (Pyr), deoxypyridinoline (Dpyr) and soft-tissue pyridinoline (stPyr) in patients with diffuse cutaneous systemic sclerosis (dcSSc, n=23) and limited cutaneous systemic sclerosis (lcSSc, n=48) and in patients with scleroderma-related diseases such as primary Raynaud's phenomenon (pRP, n=16) and secondary Raynaud's phenomenon (sRP, n=14). Healthy controls (n=18) and patients with post-menopausal osteoporosis (OP, n=35) were also investigated. RESULTS: Urinary Pyr, Dpyr and stPyr concentrations were significantly higher in patients with Raynaud's phenomenon and systemic sclerosis than in healthy controls. The highest concentrations (two to three times greater than in healthy controls) were found in patients with dcSSc. The stPyr concentration was significantly higher in patients with dcSSc than in those with lcSSc, sRP and pRP. No significant difference in stPyr concentration was found between the healthy controls and the OP group, suggesting that stPyr is derived from soft tissues rather than bone. The extent and severity of skin involvement, measured as a skin score, significantly correlated with the concentrations of stPyr and Pyr, whereas no such correlation was found for Dpyr. CONCLUSIONS: Increased urinary concentrations of piridinoline cross-links reflect alterations in collagen turnover in both Raynaud's phenomenon and systemic sclerosis. The close correlation between stPyr concentration and the extent of skin involvement in systemic sclerosis suggests that this parameter may be useful in monitoring ongoing fibrosis in this disease.

Urinary mercury levels in patients with autoantibodies to U3-RNP (fibrillarin).

OBJECTIVE: Autoantibodies to the U3 nucleolar ribonucleoprotein (RNP) fibrillarin occur in some patients with systemic sclerosis (SSc) or other connective tissue diseases and can be induced in certain mouse strains by injections of mercuric chloride, perhaps due to antigenic alteration of fibrillarin by mercury (Hg). Thus, potential occult exposure to Hg was explored in patients with SSc. METHODS: Urinary Hg levels were measured by cold vapor atomic absorption in 13 patients with antifibrillarin antibodies (11 with SSc), 39 SSc patients without antifibrillarin antibodies, and 32 healthy controls. RESULTS: Mean urinary Hg levels were significantly elevated in the antifibrillarin antibody positive patients compared to those in other patients with SSc and controls. After correction for urinary creatinine levels, mean urinary Hg levels remained significantly different than in the other 2 groups, although Hg levels in all were still within the normal or "unexposed" range. When patients and controls with low urinary creatinine levels were excluded from analysis, there were no significant differences in mean urinary Hg levels among the 3 groups. CONCLUSION: These findings suggest that further epidemiological and basic research studies of mercury are warranted in patients with SSc, especially those expressing antifibrillarin antibodies.

Evidence of free radical-mediated injury (isoprostane overproduction) in scleroderma.

OBJECTIVE: Free radical-induced oxidative stress with consequent lipid peroxidation and resultant tissue damage has been suggested as a potential mechanism of the pathogenesis of scleroderma. However, because reliable measurement of lipid peroxidation in vivo is difficult, it has not been possible to adequately examine this hypothesis. We have previously described a series of bioactive prostaglandin F2-like compounds, termed F2-isoprostanes, produced in vivo in humans by the non-cyclooxygenase, free radical-catalyzed, peroxidation of arachidonic acid and have shown them to be a reliable measure of lipid peroxidation in vivo. In the present study, we determined whether scleroderma is associated with enhanced oxidative stress. METHODS: As a measure of oxidative stress, we determined urinary concentrations of a tetranor-dicarboxylic acid metabolite of F2-isoprostanes (F2IP-M) by mass spectrometry in 8 patients with scleroderma (representing a wide spectrum of disease, including limited disease with refractory digital ulceration or pulmonary hypertension, and diffuse disease) and in 10 healthy control subjects. RESULTS: F2IP-M concentrations were significantly higher in patients with scleroderma (mean +/- SEM 3.41 +/- 0.64 ng/mg of creatinine) than in healthy controls (1.22 +/- 0.14 ng/mg of creatinine) (P = 0.002). These elevations occurred in patients with limited disease and in those with diffuse disease. CONCLUSION: The increased level of urinary F2IP-M supports the hypothesis that free radical-induced oxidative injury occurs in scleroderma and provides a biologic marker whose relationship to disease activity and disease therapy may be important. These findings may also provide a rationale for exploring whether antioxidant therapy may influence the natural course of the disease.

Dietary intake of micronutrient antioxidants in relation to blood levels in patients with systemic sclerosis.

OBJECTIVE: To document habitual intakes of micronutrient antioxidants in patients with systemic sclerosis (SSc) in light of studies reporting subnormal levels of ascorbate and selenium in this patient group. METHODS: Dietary intakes of vitamin C, selenium, alpha-tocopherol, beta-carotene, and sulfur amino acid precursors of glutathione were assessed using the 7 day weighed record in 12 patients with SSc and in 12 healthy control subjects. The intakes of the first 4 substances were examined in relation to plasma/serum levels, while intakes of sulfur amino acids were examined in relation to urinary inorganic sulfate. RESULTS: Antioxidant and sulfur amino acid intakes were similar in patients and controls, although the patients had lower levels of selenium (median 74 compared to 87 milligrams in controls; p = 0.014) and of vitamin C in plasma (median 6.0 compared to 11.1 milligrams/l in controls; p = 0.08). Inorganic sulfate concentration in urine was similar in patients and controls. CONCLUSION: Our results suggest that reduced blood levels of the water soluble antioxidants selenium and ascorbic acid in patients with SSc are not due to dietary deficiency. Other explanations must therefore be sought.

Cross-linked elastin and collagen degradation products in the urine of patients with scleroderma.

OBJECTIVE: To measure the urinary excretion of specific cross-link amino acid markers for mature elastin (desmosine [DES] and isodesmosine [IDES]) and fibrillar collagen (hydroxylysylpyridinoline [HP] and lysylpyridinoline [LP]) in systemic sclerosis (SSc) patients and healthy controls. METHODS: Urine specimens from 20 patients with SSc and 22 controls were assessed for DES, IDES, HP, and LP using high performance liquid chromatography and ultraviolet absorption spectroscopy, in combination with an isotope dilution technique in which the urine specimen was spiked with isotopically labeled cross-link amino acids. RESULTS: Mean +/- SD levels of urinary DES and IDES were elevated in SSc patients by 2-3-fold, and urinary HP and LP by 3-4-fold, compared with controls (DES 21.0 +/- 9.4 versus 7.5 +/- 1.4 micrograms/gm creatinine; HP 109.0 +/- 72.9 versus 24.9 +/- 5.7 nmoles/mmole creatinine). Nineteen of the 20 SSc patients had urinary DES and HP values that were > 3 SD above the control mean. A significant elevation in the HP:LP ratio in SSc patients as compared with controls (mean +/- SD 6.9 +/- 1.5 versus 5.5 +/- 1.3) indicated a soft tissue origin for much of the increased HP. CONCLUSION: Patients with SSc have higher levels of urinary cross-link amino acids specific for the degradation of mature collagen and elastin. These markers distinguish most SSc patients from healthy controls.