desmosine and Fibrosis

Changes in the process of cross-linking of collagen molecules are associated with defects in the biomechanical stability of the extracellular matrix. Fibrosis of skin is characterized by an increase in pyridinolines, which are hydroxylysine aldehyde derived cross-links usually absent in healthy skin. In this study, we analyzed cross-links in lipodermatosclerosis and localized scleroderma to address the question whether all the mature cross-links currently characterized are increased in fibrosis in addition to the increase in pyridinolines. As psoralen plus ultraviolet A treatment leads to clinical improvement of fibrotic plaques in localized scleroderma we analyzed the cross-link content in lesional skin after bath psoralen plus ultraviolet A therapy. In skin from patients with localized scleroderma an increase in the total number of mature cross-links was found to be due to an increase in both pyridinolines and dehydro-histidinohydroxymerodesmosine. The concentration of histidinohydroxylysinonorleucine was unchanged. By contrast, the total number of mature cross-links was decreased in lipodermatosclerosis. This decrease was caused by a decrease of lysine aldehyde derived cross-links (dehydro-histidinohydroxymerodesmosine and histidinohydroxylysinonorleucine), whereas the concentration of pyridinolines increased. A decrease in the content of pyridinolines after bath psoralen plus ultraviolet A treatment was found in six out of nine patients with localized scleroderma, which might reflect a remodeling of the extracellular matrix. Our data provide evidence that sclerosis of skin is associated with either an increase in the number of cross-links per molecule of collagen or a change in the molecular nature of the cross-links formed.

Topics: Amino Acids; Collagen; Cross-Linking Reagents; Desmosine; Fibrosis; Humans; Hydroxylation; Hydroxylysine; PUVA Therapy; Pyridones; Scleroderma, Localized; Ultraviolet Rays

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial pneumonia with upper lobe predominance and fibroelastosis. Although definite diagnosis requires surgical lung biopsy (SLB), SLB is often difficult because of its complications such as refractory pneumothorax.. To evaluate urinary desmosines (degradation product of mature elastin) as a novel biomarker in patients with PPFE.. Biopsy-proven patients with PPFE (n = 14) were prospectively enrolled. Levels of urinary desmosines in patients with PPFE were measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and compared with those in patients with idiopathic pulmonary fibrosis (IPF), patients with chronic obstructive pulmonary disease (COPD), and controls.. Levels of urinary desmosines were significantly higher in patients with PPFE than those in patients with IPF (48.4 vs. 28.6 ng/mg creatinine, p = 0.034), patients with COPD (8.0 ng/mg creatinine, p < 0.001), or controls (17.4 ng/mg creatinine, p < 0.001). Desmosines discriminated between PPFE and IPF (area under the curve [AUC] = 0.708), and between PPFE and controls (AUC = 0.956). However, levels of desmosines were not correlated with physiological parameters in patients with PPFE.. Urinary desmosines may be a useful diagnostic biomarker in patients with PPFE. Measurement of desmosines combined with specific clinical and radiological features of PPFE may lead to an accurate diagnosis without SLB in patients with PPFE.

Topics: Aged; Biomarkers; Biopsy; Desmosine; Diagnosis, Differential; Elastic Tissue; Female; Fibrosis; Humans; Idiopathic Pulmonary Fibrosis; Lung; Lung Diseases, Interstitial; Male; Middle Aged; Prospective Studies; Pulmonary Disease, Chronic Obstructive; ROC Curve; Tandem Mass Spectrometry; Tomography, X-Ray Computed

The adaptor protein p66Shc regulates intracellular oxidant levels through the modulation of a forkhead-related transcription factor (FOXO3a). The genetic ablation of p66Shc (p66Shc-/-) renders mice resistant to oxidative stress and p53-dependent apoptosis. We investigated whether p66Shc ablation in mice modifies lung cellular and molecular responses to cigarette smoke (CS) exposure. No differences between wild type (WT) and p66Shc-/- mice were observed in terms of inflammation and oxidant burden after acute CS exposure; however,p66Shc ablation modifies specific features of chronic inflammation induced by repeated exposure to CS. Unlike WT mice, p66Shc-/- mice did not develop emphysema, showing protection toward oxidative damage to DNA and apoptosis as revealed by a trivial 8-hydroxyguanosine staining and faint TUNEL and caspase-3 positivity on alveolar epithelial cells. Unexpectedly, CS exposure in p66Shc-/- mice resulted in respiratory bronchiolitis with fibrosis in surrounded alveoli. Respiratory bronchiolitis was characterized by peribronchiolar infiltrates of lymphocytes and histiocytes, accumulation of ageing pigmented macrophages within and around bronchioles, and peribronchiolar fibrosis. The blockage of apoptosis interferes with the macrophage "clearance" from alveolar spaces, favouring the accumulation of aging macrophages into alveoli and the progressive accumulation of iron pigment in long-lived senescent cells. The presence of areas of interstitial and alveolar fibrosis in peripheral parenchyma often accompanied the bronchiolar changes. Macrophages from smoking p66Shc-/- mice elaborate M2 cytokines (i.e., IL-4 and IL-13) and enzymes (i.e., chitinase and arginase I), which can promote TGF-beta expression, collagen deposition, and fibrosis in the surrounding areas. We demonstrate here that resistance to oxidative stress and p53-dependent apoptosis can modify tissue responses to CS caused by chronic inflammation without influencing early inflammatory response to CS exposure.

Topics: Animals; Apoptosis; Arginase; Bronchiolitis; Chitinases; Desmosine; Fibrosis; Hydroxyproline; Interleukin-13; Interleukin-4; Lung; Macrophages; Mice; Mice, Knockout; Oxidative Stress; Oxidoreductases; Pulmonary Emphysema; Shc Signaling Adaptor Proteins; Smoking; Src Homology 2 Domain-Containing, Transforming Protein 1; Transforming Growth Factor beta; Tumor Suppressor Protein p53

Liver growth factor (LGF), a mitogen for liver cells, reduces fibrosis in a rat model of cirrhosis. The present study assesses the possible vascular antifibrotic and antihypertensive effects of LGF treatment on spontaneously hypertensive rats (SHR).. Six-month-old male SHR and normotensive Wistar Kyoto rats (WKY) were treated with LGF (4.5 microg LGF/rat i.p. twice a week for 2 weeks). Haemodynamic parameters were measured in anaesthetized rats. Vascular structure and function were studied in carotid arteries using optical and confocal microscopy, radioimmunoassay for desmosine, and isometric tension recording.. LGF reduced systolic and diastolic blood pressure only in SHR. When compared to those of untreated SHR, carotid arteries from LGF-treated SHR showed: 1) a 50% reduction in collagen area and an increase in vascular smooth muscle cell number in the media, 2) no difference in total elastin content, but an increase in size of fenestrae in the internal elastic lamina, and 3) enhanced relaxation to acetylcholine, sodium nitroprusside, and forskolin. These effects were specific for SHR, since no changes were observed in LGF-treated WKY.. Short-term treatment with a low dose of LGF induced a large improvement in vascular structure and function and significantly reduced blood pressure in a rat model of essential hypertension. The present results could open future research to explore the vascular effects of this endogenous factor in order to determine its potential as an antifibrotic and antihypertensive agent in humans.

Topics: Acetylcholine; Animals; Bilirubin; Carotid Arteries; Cell Count; Colforsin; Collagen; Desmosine; Dose-Response Relationship, Drug; Elastin; Fibrosis; Hypertension; In Vitro Techniques; Isometric Contraction; Male; Microscopy, Confocal; Mitogens; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nitroprusside; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Serum Albumin; Serum Albumin, Human; Time Factors; Vasodilator Agents