Serum cytokines in juvenile rheumatoid arthritis: correlation with conventional inflammation parameters and clinical subtypes

Objective. To examine the usefulness of determining extended serum cytokine profiles in patients with juvenile rheumatoid arthritis (JRA), for the purpose of improving differential diagnosis and monitoring disease activity. Methods. In a 2-year prospective study, serum levels of interleukin-1β (IL-1β), soluble IL-2 receptor (sIL-2R), IL-6, IL-8, tumor necrosis factor α (TNFα), and the p55 soluble TNF receptor (sTNFR) were repeatedly determined by enzyme-linked immunosorbent assay in 40 patients with JRA, 13 patients with postinfectious arthropathies, and 30 healthy controls. The data were compared with conventional parameters of inflammation, such as C-reactive protein (CRP), iron and hemoglobin levels, erythrocyte sedimentation rate (ESR), white blood cell (WBC) counts, and platelet counts. WBC subsets were analyzed by flow cytofluorometry. Results. At the first visit and at the peak of inflammatory activity according to CRP levels and/or ESR, serum levels of sIL-2R, IL-6, and sTNFR in JRA patients correlated significantly with conventional inflammation indicators, whereas IL-1β, IL-8, and TNFα did not. No changes in leukocyte subset distribution were noted. Among the different clinical subtypes of JRA, sIL-2R, IL-6, and sTNFR values at the time of the initial visit showed a pattern similar to CRP, whereby patients with systemic disease exhibited by far the highest values. TNFα and IL-1β were variably elevated in certain JRA subtypes. Patients with postinfectious arthropathies showed elevated levels of CRP, sIL-2R, TNFα, and sTNFR, which did not differ significantly from levels in the various JRA subtypes with the exception of systemic disease. Detailed analysis of types I and II pauciarticular JRA revealed that levels of CRP, IL-1β, and TNFα were elevated in patients with type I disease. While these parameters were invariably normal in patients with type II disease, sTNFR and sIL-2R were still found to be significantly elevated. Followup studies suggested that persistently high sTNFR values are a better indicator of JRA activity than are measurements of other cytokines or CRP. Conclusion. JRA is associated with significant and consistent changes in serum levels of inflammatory cytokines and soluble receptors. For the clinical monitoring of JRA, determination of levels of sTNFR, and to some extent sIL-2R, may be particularly useful, since these determinations yield information about subtype and/or activity of disease that is not available from conventional parameters of inflammation.     

The combination of tumor necrosis factor alpha blockade with interleukin-1 and interleukin-17 blockade is more effective for controlling synovial inflammation and bone resorption in an ex vivo model.

OBJECTIVE: Anti-tumor necrosis factor a (anti-TNFalpha) therapy has shown efficacy in the treatment of rheumatoid arthritis (RA). Since interleukin-1 (IL-1), TNFalpha, and IL-17 have many additive and/or synergistic effects in vitro, we tested whether their combined inhibition by soluble receptors would lead to an enhanced effect on ex vivo models of synovial inflammation and bone destruction. METHODS: RA synovium and bone explants were cultured for 7 days in the presence of 1 microg/ml soluble TNFalpha receptor (STNFR; as in current therapy), type II soluble IL-1 receptor (sIL-1RII), or sIL-17R either alone or in combination. Their effects on the production of IL-6 and the release of C-telopeptide of type I collagen (CTX), a marker of type I collagen destruction, were measured by enzyme-linked immunosorbent assay. RESULTS: In synovium, each soluble receptor alone decreased IL-6 production and CTX release by approximately 35% and approximately 55%, respectively. The combination of all 3 receptors was more effective, inhibiting IL-6 production and collagen degradation by up to 70%. Neither sIL-17R, sIL-1RII, or sTNFR alone had no effect (or an effect of <20% inhibition) on IL-6 production in 18%, 33%, and 22%, respectively, of the samples. In bone, sIL-17R, sIL-1RII, and sTNFR decreased IL-6 production by 23%, 50%, and 37%, respectively, while the combination decreased IL-6 production by 75%. A 50% inhibition of CTX release was obtained with sIL-1RII for 63% of the samples versus 38% of the samples with either sTNFR or sIL-17R. However, the combination of all 3 receptors was not more potent than sIL-1RII alone. CONCLUSION: The inhibitory effect of sTNFR on IL-6 production and collagen degradation in RA synovium and bone was increased in combination with sIL-17R and sIL-1RII. These results support the concept of combination therapy, which may increase the percentage of responding patients as well as the degree of individual patient response.     

Soluble type II interleukin 1 (IL-1) receptor binds and blocks processing of IL-1 beta precursor and loses affinity for IL-1 receptor antagonist.

Two IL-1 receptors have been identified, termed type I and type II. The extracellular domain of the type II IL-1 receptor is released from certain cells and can function as a specific inhibitor of IL-1 beta activity. We assessed the ligand-binding properties of the type II membrane-bound and soluble IL-1 receptor (sIL-1R) from the human B cell line Raji by competition. Upon release, the affinity of sIL-1R for IL-1 alpha and IL-1 beta remained constant, and both soluble and cell surface IL-1 receptors bound to the same regions on the IL-1 beta molecule as defined by binding of a series of IL-1 beta mutant molecules. However, the affinity of sIL-1R for the IL-1 receptor antagonist (IL-1ra) decreased by a factor of 2000 when compared with the cell surface receptor. Type II sIL-1R and IL-1ra had an additive effect in inhibiting the binding of IL-1 beta to cell surface IL-1 receptors. In contrast, the combination of recombinant type 1 sIL-1R with IL-1ra abrogated the inhibition seen with each of the individual agents alone. The type II cell surface IL-1 receptor failed to bind the biologically inactive IL-1 beta precursor molecule, but binding to the IL-1 beta precursor was observed on cellular release of the receptor; this was confirmed with 35S-labeled IL-1 beta. Binding of IL-1 beta precursor by sIL-1R inhibited the precursor's ability to be processed to the mature, biologically active 17-kDa species. These observations suggest that the type II sIL-1R inhibits IL-1 beta at two steps, by preventing processing of propeptide and by blocking the interaction of mature IL-1 beta with type I IL-1 receptor. In addition, type II sIL-1R does not interfere with inhibition mediated by IL-1ra.     

Serum interleukin-6, soluble interleukin-6 receptor and soluble gp130 exhibit different patterns of age- and menopause-related changes

Growing evidence suggests that interleukin-6 (IL-6) may play a pathogenetic role in postmenopausal bone loss and in other age-related pathological conditions. In this study, we have examined the age-related changes in the serum levels of IL-6 and the soluble receptors that modulate its biological activity--soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130)--in 220 women (from 25 to 104yr old), including 22 centenarians. Serum IL-6 rose exponentially with age (r=0.74, p<0.0001). The median level of IL-6 increased almost ten-fold with age, from 1.16pg/ml in premenopausal women to 10.27pg/ml in centenarians. Serum sIL-6R and sgp130 showed an increase until the seventh decade and a progressive decrease in older ages (r=0.39, p<0.0001 and r=0.26, p=0.008, respectively). IL-6, sIL-6R and sgp130 were significantly higher in women within 10yr of menopause as compared to premenopausal subjects (1.51 vs. 1.16pg/ml, p=0.012; 41.9 vs. 35.7ng/ml, p=0.002; and 253.4 vs. 230.7ng/ml, p=0.008, respectively). In postmenopausal women, a negative correlation was found between sIL-6R and the lumbar bone mineral density (BMD) (r=-0.28, p=0.002) even after adjusting for age and weight. Furthermore, sIL-6R levels were higher in osteoporotic compared to normal women (47.9 vs. 39.5ng/ml, p=0.001). In conclusion, our results show that the serum levels of IL-6, sIL-6R and sgp130 exhibit different patterns of age- and menopause-related changes, and that the biological activity of IL-6 may be increased with age with potential implications in the age-related diseases such as osteoporosis.     

Bacterial endotoxin is an active component of cigarette smoke

BACKGROUND: Chronic bronchitis in cigarette smokers shares many clinical and histologic features with environmental lung diseases attributed to bacterial endotoxin (lipopolysaccharide [LPS]) inhalation. Experimental LPS inhalation mimics many of the acute effects of cigarette smoke in the lower airway. Therefore, we reasoned that LPS may be a biologically active component of cigarette smoke. DESIGN: The Limulus amebocyte lysate (LAL) assay was used to measure LPS in the tobacco and filter tip components of unsmoked 1R4F experimental cigarettes and commercially available "light" cigarettes, as well as in mainstream (MS) and sidestream (SS) smoke particles generated with an automated smoking machine and collected on ventilator mainflow filters. SETTING AND PARTICIPANTS: Blood LPS activity and plasma cytokine concentrations were measured in groups of healthy smokers and nonsmokers who reported to the walk-in clinic at the Baltimore VA Medical Center for unrelated complaints. MEASUREMENTS: Blood LPS levels were measured by LAL assay and plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), soluble TNF receptors I and II (sTNFR I and sTNFR II) were measured by enzyme-linked immunosorbent assay. RESULTS: Bioactive LPS was detected in both the tobacco portion (1R4F, 17.8+/-1.0 microg/cigarette; light, 26.8+/-7.3 microg/cigarette [mean+/-SE]) and filter tips (1R4F, 0.67+/-0.55 microg/cigarette; light, 0.70+/-0.39 microg/cigarette) of cigarettes. Bioactive LPS was also detected in both MS (1R4F, 120+/-64 ng/cigarette; light: 45.3+/-16 ng/cigarette) and SS smoke (1R4F, 18+/-1.5 ng/cigarette; light: 75+/-49 ng/cigarette). Although systemic absorption of inhaled LPS may occur, we failed to detect any differences between nonsmokers and smokers in median blood LPS levels (median values, 66.75 and 72.1 pg/mL, respectively; p = 0.55) or plasma concentrations of TNF-alpha (0 vs 0 pg/mL, respectively; p = 0.71), sTNFR I(1,469 vs 1,576 pg/mL, respectively), sTNFR II (2,011 vs 3,110 pg/mL, respectively), or IL-6 (8.8 vs 0 pg/mL, respectively; p = 0.20). CONCLUSIONS: Smoking one pack of cigarettes per day delivers a dose of respirable LPS that is comparable to the levels of LPS associated with adverse health effects in cotton textile workers. Thus, we suggest that the bioactive LPS in cigarette smoke may contribute to the pathogenesis of chronic bronchitis that develops in susceptible cigarette smokers.     

Role of interleukin-18 and T-helper type 1 cytokines in the development of Mycoplasma pneumoniae pneumonia in adults

STUDY OBJECTIVE: Interleukin (IL)-18 is a proinflammatory cytokine, originally termed interferon (IFN)-gamma-inducing factor, which promotes T-helper type 1 (Th1) cytokine responses. We recently reported that serum IL-18 levels were elevated in children with Mycoplasma pneumoniae pneumonia (MP). In this study, we investigated the contribution of IL-18 to the infection and assessed the Th1 cytokine response to pulmonary involvement in adults. METHODS: We investigated the clinical course, pulmonary involvement, and serum levels of IL-18, IFN-gamma, IL-12p40, and soluble IL-2 receptor (sIL-2R) in 21 patients with acute-stage MP and in 21 age- and sex-matched control subjects. RESULTS: Significantly (p < 0.001) increased serum IL-18 (median, 248 pg/mL [range, 89 to 441 pg/mL] vs. median, 126 pg/mL [range, 47 to 217 pg/mL]) and sIL-2R (median, 617 U/mL [range, 410 to 1,032 U/mL] vs. median, 425 U/mL [range, 268 to 601 U/mL]) were found in patients with MP as compared with healthy control subjects, and there was a tendency toward increased serum IFN-gamma and IL-12p40. Circulating IL-18 values had a positive correlation with serum sIL-2R levels (r = 0.62, p = 0.028) and the number of affected pulmonary lobes (sigma = 0.61, p = 0.024), but not with the serum levels of antibodies to M pneumoniae, IFN-gamma, or IL-12p40. Serum IL-18 and sIL-2R values in severe cases were significantly higher (p < 0.03) than those in mild cases. IFN-gamma and sIL-2R levels in four patients with pleural effusion were significantly (p < 0.05) higher than those in the other 17 subjects. CONCLUSIONS: Serum levels of IL-18 were raised during the acute phase of MP. We suggest IL-18 and Th1 cytokines may play a significant role in the immunopathologic responses in MP.     

Plasma interleukin-2 and a soluble/shed interleukin-2 receptor in serum of patients with Crohn's disease. Effect of cyclosporin.

Circulating concentrations of interleukin-2 (IL-2) and a soluble or shed form of the IL-2 receptor (sIL-2R) were determined by enzyme-linked immunosorbent assays (ELISA) in 61 patients with chronic active Crohn's disease (CD) initially and during a three month placebo controlled trial of cyclosporin 5-7.5 mg/kg/day. The baseline median (25-75% range) plasma IL-2 concentration was 0.6 ng/ml (0.3-2.85 ng/ml) in patients who did not receive prednisolone, 0.5 ng/ml (0.23-3.4 ng/ml) in patients who did (not significant), and 0 ng/ml (0-0.07 ng/ml) in control subjects (p less than 0.00001). The corresponding median serum sIL-2R concentrations were 747 U/ml (580-1287 U/ml), 540 U/ml (422-616 U/ml) respectively in CD patients (p = 0.006) and 320 U/ml (268-406 U/ml) in control subjects (p less than 0.00001). Increased concentrations of plasma IL-2 and serum sIL-2R were seen in 66% and 81% of the patients, respectively. A fall in serum sIL-2R was only seen in patients who improved with cyclosporin treatment (p = 0.006). At month 3 the median serum sIL-2R concentration was 440 U/ml (400-668 U/ml) v 801 U/ml (534-1067 U/ml) in patients not responding to cyclosporin (p = 0.003). No changes occurred in the placebo group. These results suggest that the IL-2 dependent pathway of immune activation is upregulated in vivo in CD and that cyclosporin may interfere with this process.     

Urinary excretion of advanced glycation endproducts in patients with type 2 diabetes and various stages of proteinuria

OBJECTIVE: The objective of the study was to detect AGE-immunoreactive proteins in urine, and to evaluate AGE excretion at various stages of diabetic nephropathy in type 2 diabetes assessed by the level of proteinuria. METHODS: AGEs were measured in 24-h urine collection of patients with normoalbuminuria (N) (n=22), microalbuminuria (Mi) (n=31), macroalbuminuria (Ma) (n=28), and overt proteinuria with elevated serum creatinine level (PC) (n=25). A competitive ELISA with polyclonal anti-AGE antibodies was used to monitor AGE excretion. RESULTS: Multiple comparison of urine AGE content among various stages of proteinuria showed significant differences (summary p<0.000). Fifty percent of samples from the group of normoalbuminuric, and only 15% of samples from the group of microalbuminuria patients were AGE negative. However, there was no significant difference in AGE excretion between the patients with persistent proteinuria and elevated serum creatinine, and those with macroalbuminuria (PC vs Ma, p=0.265). None of the samples from these two groups of patients with highest AGE content in 24-h urine was negative for AGE-immunoreactivity. In addition, the ratio between 24-h urinary AGEs and urinary albumin excretion was calculated to determine whether total 24-h urinary AGE content is an index of the toxic form of albumin released in the course of diabetic nephropathy. The ratio values were log-transformed and bivariate comparison showed significant differences between the N vs Mi (p=0.006) and Mi vs Ma (p=0.000) groups. However, there was no significant difference (p=0.407) between values in the Ma and PC groups of patients. Multiple stepwise regression analysis indicated a relationship of urinary AGE-immunoreactivity with creatinine clearance values (r=0.52, p<0.001). CONCLUSION: The study demonstrated the presence of AGE-immunoreactivity in the urine of diabetic patients with various stages of proteinuria. Study results pointed to creatinine clearance as the main predictor of AGE excretion. Therefore, the measurement of urinary AGE appears to offer limited extra information in patients with impaired renal function.     

Differences in the profiles of circulating levels of soluble tumor necrosis factor receptors and interleukin 1 receptor antagonist reflect the heterogeneity of the subgroups of juvenile rheumatoid arthritis

OBJECTIVE: To determine whether levels of soluble tumor necrosis factor receptor 55 (sTNFR55), sTNFR75, and interleukin 1 receptor antagonist (IL-1Ra) can differentiate different subtypes of juvenile rheumatoid arthritis (JRA), and to determine if the levels of these proteins correlate with disease activity. METHODS: Serum sTNFR (55 and 75) and IL-1Ra levels were measured by ELISA in 34 patients with JRA and these values were correlated with disease subtype and activity. RESULTS: Serum sTNFR55 levels were significantly elevated in patients with systemic onset JRA (SoJRA) (mean +/- 2 SD, 2.9 +/- 1.8 ng/ml) (p < or = 0.05) compared to rheumatoid factor positive (RF+) polyarticular JRA (2.1 +/- 0.6), RF-polyarticular JRA (1.5 +/- 0.6), and pauciarticular JRA (1.4 +/- 0.4). There was a trend for elevation of sTNFR75 levels in patients with SoJRA compared to other subtypes (p = 0.08). More patients had elevated levels of sTNFR75 than sTNFR55 (15 vs 7). This was true for all subsets (SoJRA 7 vs 5; polyarticular JRA 4 vs 2; and pauciarticular JRA 4 vs 0). In contrast to sTNFR, IL-1Ra levels were significantly elevated in RF+ polyarticular JRA compared to the other subgroups (p < or = 0.001). We found statistically significant Pearson correlations between (1) sTNFR75 and hemoglobin concentration: and (2) IL-1Ra and number of active joints and number of joints with effusions. CONCLUSION: The increased serum level of sTNF receptors in SoJRA suggests that TNF is likely more important than IL-1 in systemic inflammation and in particular in SoJRA. Conversely, IL-1 is likely more important in the inflammatory arthritis of JRA and in particular in the pathogenesis of RF+ polyarticular JRA. Our results suggest that cytokines have differing roles in JRA subtypes and likely reflect JRA subtype heterogeneity.     

Pretreatment cytokine profiles of peripheral blood mononuclear cells and serum from patients with rheumatoid arthritis in different american college of rheumatology response groups to methotrexate

OBJECTIVE: To determine the role of putative target cytokines for methotrexate (MTX) treatment in patients with rheumatoid arthritis (RA) as predictors for treatment outcome. METHODS: Fifty consecutive patients with RA were characterized according to demographic and disease associated features and followed prospectively before and after 6 months of treatment with MTX. Before starting MTX treatment, serum was obtained from each patient and peripheral blood mononuclear cells (PBMC) were isolated. PBMC were cultured 2 days under resting conditions, and interleukin 1 receptor antagonist (IL-1ra), IL-1beta, soluble tumor necrosis factor receptor p55+75 (sTNFR p55+p75), and TNF-a release into cell culture supernatants and corresponding serum cytokine levels were determined by specific ELISA. Constitutive production and circulating levels of cytokines and cytokine inhibitors were correlated to the clinical response after 6 months of MTX treatment, and patients were categorized into 4 different groups according to the American College of Rheumatology (ACR) response criteria (ACR < 20, 20-50, 50-70, > 70% improvement from baseline). RESULTS: Good (ACR 50-70) or excellent (ACR > 70) responses to MTX treatment were seen in groups of patients with a higher proportion of males (25 and 43%) associated with a significantly lower ratio of IL-1ra/IL-1beta (p < 0.00001) constitutively produced by PBMC (ratio < 100) compared with nonresponding (ACR < 20) patients (males 7.7%; ratio > 100). The ratios in 3 female poor responders (ACR 20-50) were in between. The decreased ratios of IL-1ra/IL-1beta in most good and excellent responders were due to an enhanced constitutive IL-1beta release from PBMC (p < 0.004) compared to the groups of non or poor responders. Much less pronounced, there was a slightly significant increase of sTNFR p55 shedding from PBMC and increase of sTNFR p75 serum levels in good and excellent responders (both p < 0.02). In contrast, there were no intergroup differences regarding constitutive IL-1ra release, sTNFR p75 shedding, and IL-1ra and sTNFR p55 serum levels and various demographic and disease associated characteristics of patients. CONCLUSION: Determination of cellularly produced IL-1beta and even more of the IL-1ra/IL-1beta synthesis in PBMC may be useful to predict the outcome of RA patients undergoing treatment with MTX and may characterize a subset of RA that is more responsive to IL-1 directed therapeutic interventions.     

Physical training modulates proinflammatory cytokines and the soluble Fas/soluble Fas ligand system in patients with chronic heart failure

OBJECTIVES: We sought to investigate the effects of physical training on circulating proinflammatory cytokines and the soluble apoptosis mediators Fas (sFas) and Fas ligand (sFasL) in patients with chronic heart failure (CHF). BACKGROUND: Recent investigations have shown an overexpression of circulating proinflammatory cytokines and soluble apoptosis mediators in patients with CHF, which may be related to their exercise intolerance and clinical deterioration. METHODS: Plasma levels of tumor necrosis factor-alpha (TNF-alpha), soluble TNF receptors I and II (sTNF-RI and sTNF-RII, respectively), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sFas and sFasL were measured in 24 patients with stable CHF (New York Heart Association functional class II/III; left ventricular ejection fraction 23.2 +/- 1.3%) and in 20 normal control subjects before and after a 12-week program of physical training in a randomized, crossover design. Functional status of patients with CHF was evaluated by using a cardiorespiratory exercise test to measure peak oxygen consumption (VO2max). RESULTS: Physical training produced a significant reduction in plasma levels of TNF-alpha (7.5 +/- 1.0 pg/ml vs. 4.6 +/- 0.7 pg/ml, p < 0.001), sTNF-RI (3.3 +/- 0.2 ng/ml vs. 2.7 +/- 0.2 ng/ml, p < 0.005), sTNF-RII (2.6 +/- 0.2 ng/ml vs. 2.3 +/- 0.2 ng/ml, p = 0.06), IL-6 (8.3 +/- 1.2 pg/ml vs. 5.9 +/- 0.8 pg/ml, p < 0.005), sIL-6R (34.0 +/- 3.0 ng/ml vs. 29.2 +/- 3.0 ng/ml, p < 0.01), sFas (5.5 +/- 0.7 ng/ml vs. 4.5 +/- 0.8 ng/ml, p = 0.05) and sFasL (34.9 +/- 5.0 pg/ml vs. 25.2 +/- 4.0 pg/ml, p < 0.05), as well as a significant increase in VO2max (16.3 +/- 0.7 ml/kg per min vs. 18.7 +/- 0.8 ml/kg per min, p < 0.001). Good correlations were found between a training-induced increase in VO2max and a training-induced reduction in levels of the proinflammatory cytokine TNF-alpha (r = -0.54, p < 0.01) and the apoptosis inducer sFasL (r = -0.57, p < 0.005) in patients with CHF. In contrast, no significant difference in circulating cytokines and apoptotic markers was found with physical training in normal subjects. CONCLUSIONS: Physical training reduces plasma levels of proinflammatory cytokines and the sFas/sFasL system in patients with CHF. These immunomodulatory effects may be related to the training-induced improvement in functional status of patients with CHF.     

Soluble interleukin-6 receptors in inflammatory bowel disease: relation to circulating interleukin-6.

The in vivo appearance of soluble interleukin (IL)-6 receptor (sIL-6R) in serum from patients with inflammatory bowel disease was examined using an enzyme linked immunosorbent assay (ELISA). The serum sIL-6R concentrations in patients with active disease (ulcerative colitis, 148.4 (5.1); Crohn's disease, 142.3 (9.3) ng/ml; mean (SEM)) were significantly raised compared with those in patients with inactive disease (ulcerative colitis, 116.2 (7.2); Crohn's disease, 114.3 (7.1) ng/ml), some other type of colitis (104.8 (11.6) ng/ml), or in normal subjects (107.3 (2.4) ng/ml). These differences were also seen in paired samples examined during both active and inactive phases. Additionally, serum sIL-6R and IL-6 concentrations correlated significantly with C-reactive protein levels in both ulcerative colitis and Crohn's disease patients (r = 0.23 and 0.56, respectively; p < 0.05 for both). Furthermore, gel filtration analysis of serum from these patients showed two major peaks of immunoreactive IL-6-one peak corresponding to free IL-6 and another peak to sIL-6R-bound IL-6-this was further confirmed by a luminescence sandwich ELISA. These results, together with its in vitro effects, indicate that natural sIL-6R may function as a powerful enhancer of the IL-6-dependent immune processes observed in inflammatory bowel disease.     

Insulin resistance as a determinant of platelet activation in obese women.

OBJECTIVES: We tested the hypothesis that insulin resistance, per se, contributes to increased platelet activation in obesity, independently of underlying inflammation. BACKGROUND: Obesity, insulin resistance, and atherosclerosis are closely linked phenomena associated with low-grade inflammation. Obesity is associated with persistent platelet activation in otherwise healthy women. METHODS: We performed a cross-sectional study in 40 obese and 20 non-obese healthy women using urinary thromboxane metabolite excretion as a non-invasive index of platelet activation. An index of insulin sensitivity, S(I), and plasma adiponectin, C-reactive protein (CRP), and CD40 ligand (CD40L) levels were measured. RESULTS: Obese women had significantly (p < 0.0001) higher 11-dehydro-thromboxane B2 (11-dehydro-TXB2) excretion (median 718 vs. 211 pg/mg creatinine), CRP (1.13 vs. 0.48 mg/l), and CD40L levels (4.45 vs. 0.90 ng/ml) than controls. Obese women had lower S(I) (median 2.51 vs. 5.0 10(4) min(-1)/[microU/ml], p < 0.002) and adiponectin (6.3 vs. 10 microg/ml, p < 0.01) than control subjects. On multiple regression analysis, waist-to-hip ratio (beta = 0.27, p < 0.05) and S(I) (beta = -0.72, p < 0.04) predicted 11-dehydro-TXB2 excretion rate, independently of adiponectin, CRP, CD40L, and lipid patterns. In order to investigate the cause-effect relationship of these associations, we examined the effects of a 12-week weight loss program or a 3-week pioglitazone treatment on urinary 11-dehydro-TXB2 in 10 women with impaired S(I) and visceral obesity. Successful weight loss (0.6 kg loss/week) achieved in 5 subjects was associated with increased S(I) (+92%) and decreased CD40L (-27%), CRP (-37%), and 11-dehydro-TXB2 (-53%) (p < 0.05). Consistently, improvement of insulin sensitivity achieved with pioglitazone significantly decreased urinary 11-dehydro-TXB2 excretion (-43%, p < 0.05) without changes in body weight. CONCLUSIONS: Insulin resistance is a major determinant of platelet activation in female obesity.     

Antihypertensive effect of enalapril in essential hypertension: role of prostacyclin

The effects of enalapril alone and in combination with the cyclooxygenase inhibitors sulindac and indomethacin on blood pressure (BP), plasma aldosterone, renin activity and converting enzyme activity were evaluated in 29 patients with mild to moderate essential hypertension, 26 of whom had low plasma renin activity. Patients were randomly assigned to one of three treatment groups. All patients underwent a 4-week placebo phase (phase I), then received enalapril (20 mg BID) for 4 weeks (phase II). In phase III, group I (n = 10) continued on enalapril alone; group II (n = 9) received sulindac 200 mg BID plus enalapril, and group III (n = 10) received indomethacin 50 mg BID plus enalapril, all for 4 weeks. Enalapril lowered BP significantly (mean supine BP 149/100 in phase I vs. 134/90 in phase II, p less than 0.05) without inhibiting aldosterone production. The BP effect was not blunted by concomitant administration of sulindac or indomethacin. Enalapril lowered converting enzyme activity to 25% to 30% of baseline and tended to increase renin activity. In the 10 patients who received indomethacin (group III), the effects of enalapril alone and enalapril plus indomethacin on urinary excretion of 6-keto prostaglandin F1 alpha (PGF1 alpha), a stable metabolite of prostacyclin (PGI2), were examined. Enalapril increased urinary 6-keto PGF1 alpha in group III from 118 +/- 23 to 194 +/- 38 ng/g creatinine (p less than 0.05), while addition of indomethacin reduced 6-keto PGF1 alpha to basal levels (138 +/- 26 ng/g creatinine).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of acute hyperglycaemia on selected plasma and urinary cytokine antagonists in Type 1 diabetes mellitus

AIMS/HYPOTHESIS: Several cytokines have been implicated in the pathogenesis of diabetic nephropathy. Their ability to generate a biological response in vivo is modulated by specific antagonists and soluble receptors. The aims of the study were firstly, to measure the interleukin 1 receptor antagonist (IL-1ra) and tumour necrosis factor alpha soluble receptors p55 (TNFsr1) and p75 (TNFsr2) in plasma and urine, and secondly to test their response to acutely induced hyperglycaemia in Type 1 diabetes mellitus (DM 1). METHODS: Plasma concentrations and urinary excretions of IL-1ra, TNFsr1 and TNFsr2 were measured in two 90-min periods of glycaemic clamp-induced normoglycaemia and hyperglycaemia (5 and 12 mmol/l; study 1) and during time-controlled normoglycaemia (5 and 5 mmol/l; study 2) in 20 Type 1 diabetic patients with normal albumin excretion and normal glomerular filtration rate, and in 11 weight-, age- and sex-matched healthy control subjects. RESULTS: The plasma concentrations of IL-1ra, TNFsr1 and TNFsr2 were comparable in Type 1 diabetic patients and control subjects, and no significant changes during study 1 and study 2 were found. Urinary IL-1ra excretion measured during normoglycaemia was higher in Type 1 diabetic patients compared to control subjects ( p<0.05). In diabetic patients, it decreased in study 1 compared to study 2 ( p<0.05), while it did not change in control subjects. The urinary excretions of TNFsr1 and TNFsr2 during normoglycaemia were comparable in diabetic patients and controls. In diabetic patients, hyperglycaemia decreased TNFsr1 excretion (study 1 vs study 2; p<0.01), while TNFsr1 excretion did not change in control subjects. Hyperglycaemia did not affect TNFsr2 excretion in diabetic patients, while it led to an increase in TNFsr2 excretion in control subjects (study 1 vs study 2; p<0.05). Despite comparable renal haemodynamics, diabetic patients had lower fractional excretion of sodium compared to control subjects ( p<0.01). No significant relationships between cytokine antagonists and renal functions have been found. CONCLUSION/INTERPRETATION: Type 1 diabetic patients with normal renal haemodynamics are associated with impaired regulation of renal IL-1ra, TNFsr1 and TNFsr2 production with a potential impact on local control of cytokine activity in the kidneys.     

Circulating soluble tumor necrosis factor receptors,interleukin-2 receptors,tumor necrosis factor α, and interleukin-6 levels in rheumatoid arthritis.

Objective. To assess whether circulating concentrations of soluble tumor necrosis factor receptors (sTNFR; p55 and p75), soluble interleukin-2 receptors (sIL-2R), tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) reflect clinical response and whether changes are dependent on the drug used in rheumatoid arthritis (RA) patients taking methotrexate (MTX) or azathioprine (AZA). Methods. These cytokines and soluble receptors were assessed in 20 control subjects and serially for up to 48 weeks in 61 RA patients, by bioassay (IL-6) and immunoassays (sTNFR, sIL-2R, TNFα, and IL-6). Results. Concentrations of p55 and p75, sIL-2R, and TNFα (but not IL-6) were significantly higher in RA patients than in controls. Significant decreases in sIL-2R and p55 concentrations were associated with clinical improvement and were observed in patients treated with MTX, but not AZA. Both treatments induced decreases in IL-6 concentrations, but circulating AZA (or its metabolites) appears to interfere with the measurement of IL-6 bioactivity. TNFα and p75 levels did not show significant changes. Conclusion. Measurement of circulating sIL-2R, p55, and IL-6 may be useful in the evaluation of RA disease activity and response to therapy. Interference by circulating levels of drugs must be ruled out when bioassays are used to evaluate cytokine levels.     

Serum levels of IL-10, IL-6, IL-1ra, and sIL-2R in patients with psoriatic arthritis

Our objective was to evaluate the levels of interleukin-6 (IL-6), soluble receptors of IL-2 (sIL-2R), IL-10, and IL-1 receptor antagonists (IL-1ra) in the serum of patients with psoriatic arthritis (PsA) and to assess the correlation between these levels and parameters of clinical activity of skin and joint disease. In total, 34 patients with PsA and ten healthy volunteers participated in the study. Assessment of joint disease included duration of morning stiffness, number of tender and swollen joints, right and left grip, the presence of inflammatory spinal back pain, and Schober test. Current severity of skin disease was graded according to the psoriasis area and severity index (PASI). Erythrocyte sedimentation rate (ESR) was determined as a marker of disease activity. Serum levels of IL-6, sIL-2R, IL-1ra, and IL-10 were measured by an enzyme immunoassay kit. Significantly higher serum levels of IL-6, sIL-2R, IL-1ra, and IL-10 were found in patients with PsA in comparison with healthy volunteers. A statistically significant correlation was found between levels of sIL-2R and PASI, whereas no association was found with clinical parameters of joint severity. Levels of IL-1ra correlated with the number of tender and swollen joints. No correlation was found between levels of IL-6, IL-10, and clinical parameters of skin and joint severity. In the group of patients with PsA, serum levels of sIL-2R clearly correlated with severity of skin disease, whereas levels of IL-1ra were associated with joint severity. Received: 18 June 1999 / Accepted: 1 October 1999     

Urinary prolactin as a reliable marker for preeclampsia, its severity, and the occurrence of adverse pregnancy outcomes

CONTEXT: It has been proposed that preeclampsia may result from of an imbalance in angiogenic factors. Although prolactin (PRL) is mainly related to lactation, it is also involved in other biological functions, including angiogenesis. OBJECTIVE: Our objective was to determine the relationship among preeclampsia, serum and urinary PRL (uPRL) levels, and excretion of antiangiogenic PRL fragments in urine. STUDY DESIGN: Using a cross-sectional design, uPRL and serum PRL levels, and the presence of PRL isoforms were determined in 546 pregnant women: 207 healthy pregnant, 124 with gestational hypertension, 48 with mild preeclampsia, and 167 with severe preeclampsia (sPE). RESULTS: uPRL concentrations were significantly (P < 0.001) higher in preeclampsia (11.99 ng/mg creatinine) than in healthy pregnancy (0.20 ng/mg creatinine) and gestational hypertension (0.19 ng/mg creatinine), and were even higher in sPE compared with mild preeclampsia (21.20 vs. 2.77 ng/mg creatinine, respectively; P < 0.001). Antiangiogenic PRL fragments (14-16 kDa) were detected in 21.6% of urine samples from women with sPE but in none from other groups. Patients with hemolysis, elevated liver enzymes, low platelet count syndrome, and/or eclampsia, placental abruption, acute renal failure, and pulmonary edema exhibited highest uPRL concentrations (P < or = 0.028) and frequency of antiangiogenic PRL fragments in urine (P < or = 0.036). High-serum PRL levels were associated with sPE independently of gestational age, proteinuria, and prolactinuria (P = 0.032). CONCLUSIONS: Preeclampsia is characterized by increased uPRL excretion. uPRL concentrations and their isoforms appear to be suitable markers to assess the severity of preeclampsia and occurrence of adverse outcomes. PRL and and/or its isoforms might be involved in the pathophysiology of preeclampsia.     

Impaired urinary excretion of soluble IL-2 receptors in patients with systemic lupus erythematosus and rheumatoid arthritis.

Several previous studies have demonstrated increased in vivo release of soluble interleukin-2 receptors (sIL-2R) in patients with disorders associated with cellular activation. In this study attempting to understand better the role of sIL-2R released in vivo, we investigated the sIL-2R levels in paired serum and urine samples from 25 patients with systemic lupus erythematosus (SLE), 41 patients with rheumatoid arthritis (RA) and 20 healthy subjects. Using an ELISA for sIL-2R, we detected significantly increased urinary sIL-2R levels in normal individuals (868 +/- 114 units/ml) compared to the corresponding serum samples (209 +/- 25, P < 0.001, mean urine/serum sIL-2R ratio: 4.5 +/- 0.6), which suggests that the clearance of sIL-2R from circulation is largely kidney-dependent. The patients with SLE and RA exhibited significantly increased serum sIL-2R levels compared to normals (682 +/- 115 and 734 +/- 101 units/ml, respectively, P < 0.001) and these levels correlated with disease activity. However, urinary excretion of sIL-2R in these patients (SLE: 620 +/- 154 units/ml; RA: 1084 +/- 148 units/ml) was found to be significantly decreased (mean urine/serum sIL-2R ratio in SLE: 0.9 +/- 0.2; in RA: 1.9 +/- 0.2; P < 0.001) compared to normals, possibly contributing to the accumulation of these soluble receptors in the serum of autoimmune patients after their release from cells. Our findings can be attributed either to the binding of the sIL-2R to serum protein(s) or to distinct structural features of serum sIL-2R in SLE and RA patients, interfering with the urinary excretion of these molecules.     

Soluble interleukin-6 receptor in rheumatoid arthritis

Abstract

To investigate the pathophysiologic role of soluble interleukin-6 receptor (sIL-6R) in patients with rheumatoid arthritis (RA), serum sIL-6R levels were measured in 15 RA patients and 15 healthy control subjects using a sandwich enzyme-linked immunosorbent assay. Correlation analysis was performed between sIL-6R levels and clinical variables such as joint score, Lansbury’s index, C-reactive protein and platelet counts. Levels of sIL-6R and IL-6 were also measured in paired samples of serum and synovial fluid obtained at the same time from nine RA patients. Serum sIL-6R levels in RA patients (153.9±56.9 ng/ml) were significantly higher than those of control subjects (115.1±19.1 ng/ml; P<0.05). However, sIL-6R levels did not correlate with any clinical characteristic of RA. sIL-6R was detectable in synovial fluid, but was invariably lower than in serum, in contrast to IL-6 (i.e. much higher in synovial fluid). It correlated neither with total cell nor neutrophil number in synovial fluid. Serum C-reactive protein levels were significantly correlated with IL-6 in synovial fluid, but not with sIL-6R in synovial fluid. These results indicate that serum sIL-6R levels are increased in RA patients. High levels of serum sIL-6R did not seem to be derived from the site of local inflammation. The readily detectable sIL-6R in synovial fluid may co-operate with IL-6 in the pathogenesis of synovitis in RA.