Sonographic assessment of interstitial lung disease in patients with rheumatoid arthritis, systemic sclerosis and systemic lupus erythematosus.

OBJECTIVES: The usefulness of transthoracic ultrasound in the evaluation of lung diseases has been highlighted in the past decades. The aim of our study is to determine the diagnostic value of lung ultrasound in the detection of interstitial pulmonary fibrosis in patients with a rheumatic disease. Furthermore, we studied the possible correlation between the underlying disease and the frequency of pathological ultrasound findings. METHODS: A sample of 45 consecutive patients with RA (n=25), SSc (n=14) and SLE (n=6) and 40 healthy volunteers were enrolled into the study. Every study patient underwent both, lung sonography and HRCT. The following ultrasound findings were documented in each study patient: B- lines, subpleural nodes and irregularities of the pleura. HRCT was analysed by an experienced radiologist blind to sonography findings. RESULTS: Twenty-eight percent of the RA cohort, 64% of the SSc patients and four out of 6 SLE patients showed ILD on HRCT. Pathological ultrasound patterns were significant more frequent in the ILD group than in the non-ILD group (comet tail artifacts/B-pattern: 100% vs. 12%, p<0.001; subpleural nodes: 55 % vs. 17%, p=0.006; thickenings of the pleural line: 95% vs. 12.5%, p<0.001). Subpleural nodes were present in 100% of the RA patients vs. 22% the SSc patients (p=0.003) and 50% of the SLE patients (p=0.049) with ILD. An irregular pleural line>3 mm was documented in 100% of SSC and SLE patients with ILD, vs. 86% of ILD patients suffering from RA (p=ns). CONCLUSIONS: Transthoracic ultrasound of the lung might be a sensitive non-invasive tool to observe early stage interstitial lung disease in rheumatic diseases.

The immunosuppressant FTY720 (fingolimod) enhances glycosaminoglycan depletion in articular cartilage.

BACKGROUND: FTY720 (Fingolimod) is a novel immunosuppressive drug investigated in clinical trials for organ transplantation and multiple sclerosis. It acts as a functional sphingosine-1-phosphate (S1P) receptor antagonist, thereby inhibiting the egress of lymphocytes from secondary lymphoid organs. As S1P is able to prevent IL-1beta induced cartilage degradation, we examined the direct impact of FTY720 on cytokine induced cartilage destruction. METHODS: Bovine chondrocytes were treated with the bioactive phosphorylated form of FTY720 (FTY720-P) in combination with IL-1beta or TNF-alpha. Expression of MMP-1,-3.-13, iNOS and ADAMTS-4,-5 and COX-2 was evaluated using quantitative real-time PCR and western blot. Glycosaminoglycan depletion from cartilage explants was determined using a 1,9-dimethylene blue assay and safranin O staining. RESULTS: FTY720-P significantly reduced IL-1beta and TNF-alpha induced expression of iNOS. In contrast FTY720-P increased MMP-3 and ADAMTS-5 mRNA expression. Furthermore depletion of glycosaminoglycan from cartilage explants by IL-1beta and TNF-alpha was significantly enhanced by FTY720-P in an MMP-3 dependent manner. CONCLUSIONS: Our results suggest that FTY720 may enhance cartilage degradation in pro-inflammatory environment.

Exercise Pulmonary Resistances Predict Long-Term Survival in Systemic Sclerosis.

BACKGROUND: Pulmonary hemodynamics during exercise may reveal early pulmonary vascular disease and may be of clinical and prognostic relevance in systemic sclerosis (SSc). We aimed to assess the prognostic relevance of exercise pulmonary resistances in patients with SSc with no or mildly increased mean pulmonary arterial pressure (mPAP). RESEARCH QUESTION: Are pulmonary resistances at peak exercise independent predictors of mortality in systemic sclerosis? STUDY DESIGN AND METHODS: All SSc patients with resting mPAP < 25 mm Hg and at least one year of follow-up data who underwent symptom-limited exercise right heart catheterization between April 2005 and December 2018 were analyzed retrospectively. Age-adjusted Cox regression analysis was used to evaluate the association between pulmonary resistances and all-cause mortality. RESULTS: The cohort consisted of 80 patients: 73 women and 7 men with a mean age of 57 years (interquartile range [IQR], 47-67 years) and a mean follow-up time of 10.4 years (IQR, 8.5-11.8 years). At baseline, resting mPAP of ≤ 20 mm Hg and 21 to 24 mm Hg was found in 68 and 12 patients, respectively. Pulmonary vascular resistance (PVR) and total pulmonary resistance (TPR) at peak exercise were associated significantly with mortality (P = .006 [hazard ratio (HR), 2.20; 95% CI, 1.26-3.87] and P = .026 [HR, 1.56; 95% CI, 1.06-2.29]), whereas resting PVR and TPR were not (P = .087 [HR, 2.27; 95% CI, 0.89-5.83] and P = .079 [HR, 1.88; 95% CI, 0.93-3.80]). The mPAP per cardiac output (CO) and transpulmonary gradient (TPG) per CO slopes were associated significantly with mortality (P = .047 [HR, 1.14; 95% CI, 1.002-1.286] and P = .034 [HR, 1.34; 95% CI, 1.02-1.76]) as well. The area under the receiver operating characteristic curve for exercise PVR to predict 10-year mortality was 0.917 (95% CI, 0.797-1.000). INTERPRETATION: PVR and TPR at peak exercise, mPAP/CO slope, and TPG/CO slope are predictors of age-adjusted long-term mortality in SSc patients with no or mildly increased pulmonary arterial pressure.

Effect of Laminin-A4 inhibition on cluster formation of human osteoarthritic chondrocytes.

Formation of chondrocyte clusters is not only a morphological sign of osteoarthritis but it is also observed in cell culture. Active locomotion of chondrocytes is controlled by integrins in vitro. Integrins bind to Laminin-A4 (LAMA4), a protein that is highly expressed in vivo in clusters of hypertrophic chondrocytes. We tested if LAMA4 is relevant for cluster formation. Human chondrocytes were cultured in a 2D matrigel model and treated with different concentrations of a monoclonal inhibitory anti-LAMA4-antibody. Migration and cluster formation was analysed using live cell imaging technique. Full genome gene expression analysis was performed to assess the effect of LAMA4 inhibition. The data set were screened for genes relevant to cell motility. F-actin staining was performed to document cytoskeletal changes. Anti-LAMA4 treatment significantly reduced the rate of cluster formation in human chondrocytes. Cells changed their surface morphology and exhibited fewer protrusions. Expression of genes associated with cellular motility and migration was affected by anti-LAMA4 treatment. LAMA4-integrin signalling affects chondrocyte morphology and gene expression in vitro, thereby contributing to cluster formation in human osteoarthritic chondrocytes.

Epigenetic differences in human cartilage between mild and severe OA.

The development of osteoarthritis (OA) depends on genetic and environmental factors, which influence the biology of the chondrocyte via epigenetic regulation. Changes within the epigenome might lead the way to discovery of new pathogenetic pathways. We performed a genome-wide methylation screening to identify potential differences between paired mild and severe osteoarthritic human cartilage. Sixteen female patients suffering from OA underwent total knee joint replacement. Cartilage specimens collected from corresponding macroscopically undamaged and from damaged areas were processed for DNA extraction and histology to evaluate the histological grading of the disease. Paired specimens were analysed for the methylation status of the whole genome using human promoter microarrays (Agilent, Santa Clara, CA). Selected target genes were then validated via methylation-specific qPCR. One thousand two hundred and fourteen genetic targets were identified differentially methylated between mild and severe OA. One thousand and seventy of these targets were found hypermethylated and 144 hypomethylated. The descriptive analysis of these genes by Gene Ontology (GO), KEGG pathway and protein domain analyses points to pathways of development and differentiation. We identified a list of genes which are differently methylated in mild and severe OA cartilage. Within the pathways of growth and development new therapeutic targets might arise by improving our understanding of pathogenetic mechanisms in OA.

Assessment of pulmonary arterial pressure during exercise in collagen vascular disease: echocardiography vs right-sided heart catheterization.

BACKGROUND: This study compared the results of exercise Doppler echocardiography (EDE) with right-sided heart catheterization (RHC) and evaluated the combination of EDE and cardiopulmonary exercise testing (CPET) as a screening method for early pulmonary vasculopathy in patients with connective tissue disease. METHODS: Patients (N = 52) with connective tissue disease (predominantly systemic sclerosis) and without known pulmonary arterial hypertension underwent both EDE and CPET. If systolic pulmonary arterial pressure (SPAP) was > 40 mm Hg during exercise or peak oxygen uptake (Vo(2)) was < 75% predicted, RHC was suggested. RESULTS: EDE showed an SPAP > 40 mm Hg during exercise in 26/52 patients. Additionally, CPET showed a peak Vo(2) < 75% predicted in 10/26 patients with SPAP 40 mm Hg in 25 patients (n = 1 at rest, n = 24 during exercise). SPAP values assessed by EDE showed no significant difference vs RHC at rest, 25 W, 50 W, and maximal exercise (difference [95% CI]: 0.3 [-2.7; 3.2], -1.3 [-7.1; 4.4], 0.9 [-7.7; 5.9], and -5.6 [-13.5; 2.2] mm Hg). Eight patients with exercise SPAP > 40 mm Hg had an exercise pulmonary arterial wedge pressure > 20 mm Hg, suggesting exercise-induced left ventricular diastolic dysfunction not detectable by EDE. CONCLUSIONS: EDE appears to be a reasonable noninvasive method to detect SPAP increase during exercise in connective tissue disease. In combination with CPET, it may be a useful screening tool for early pulmonary vasculopathy, although RHC remains the gold standard for hemodynamic assessment. TRIAL REGISTRATION: clinicaltrials.gov; Identifier: NCT00609349 (Early Recognition of Pulmonary Arterial Hypertension).

Stimulated active potassium secretion in a patient with colonic pseudo-obstruction: a new mechanism of secretory diarrhea.

BACKGROUND & AIMS: Secretory diarrhea is caused by inhibition of intestinal active sodium absorption and stimulation of active chloride secretion. The resulting increase in fecal sodium salts causes an isotonic increase in fecal water output. Abnormalities in potassium transport are not known to be a cause of secretory diarrhea. The aim of our report is to describe a patient with secretory diarrhea that was mediated by excess intestinal secretion of potassium. METHODS: A 78-year-old woman developed colonic pseudo-obstruction, complicated by severe diarrhea and hypokalemia. Her stools were collected quantitatively on 11 occasions and analyzed for electrolyte concentrations. Rectosigmoid potential difference was measured. RESULTS: The diarrheal fluid had a very high potassium concentration (130-170 mEq/L) and a very low sodium concentration (4-15 mEq/L). Stool potassium losses were as high as 256 mEq/day (normal, 9 mEq/day), and fecal sodium losses were never higher than 13 mEq/day. Potential difference between colonic lumen and a peripheral reference electrode was -14 mV (lumen side negative). CONCLUSIONS: Fecal potassium salts were the exclusive driving force for severe secretory diarrhea in a patient with colonic pseudo-obstruction. The high fecal output of potassium was due to stimulation of active colonic potassium secretion, possibly because of changes in autonomic nervous system activity and distention of the colon in association with colonic pseudo-obstruction. The extremely low fecal excretion of sodium indicates that active sodium absorption was not inhibited. This case study reveals an ion transport mechanism of secretory diarrhea that has not been previously appreciated.