Decorin Is Significantly Overexpressed in Nephrogenic Systemic Fibrosis
ABSTRACT The role of the proteoglycans in the pathogenesis of nephrogenic systemic fibrosis (NSF) is unclear. We assessed expression of decorin, versican, and transforming growth factor beta1 (TGF-beta1) in skin specimens of 10 patients with biopsy-proven NSF and different control groups. Real-time reverse transcription-polymerase chain reaction studies and immunohistochemical analysis were performed on full-thickness skin specimens. The messenger RNA (mRNA) and protein levels of decorin were significantly higher in the skin lesions of patients with NSF than in skin lesions of patients with systemic sclerosis, patients undergoing hemodialysis, and healthy subjects. The versican mRNA levels in NSF lesions differed significantly only from the levels in healthy subjects. TGF-beta1 mRNA expression was significantly overexpressed in NSF lesions compared with control skin specimens investigated. In NSF specimens, the mRNA expression of TGF-beta1 and decorin were highly correlated (r = 0.92). Our results suggest that decorin and TGF-beta1 may have a fundamental role in the pathogenesis of NSF. Conversely, versican seems less likely to be of pathogenetic significance in NSF.
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ABSTRACT: Nephrogenic systemic fibrosis (NSF) is an uncommon fibrotic disorder occurring after administration of linear gadolinium contrast agents in patients with severely decreased kidney function. The underlying pathogenetic mechanism of fibrosis remains to be elucidated. Transforming growth factor beta (TGF-beta), a key player in the pathogenesis of fibrotic disorders, has been found to be overexpressed in NSF skin lesions. The aim of this study is to analyze the TGF-beta-SMAD-connective tissue growth factor (CTGF) axis in NSF skin lesions compared with skin specimens from patients with systemic sclerosis, hemodialysis patients without NSF, and healthy controls. Additionally, expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) and antifibrotic tumor necrosis factor alpha (TNF-alpha) were examined. Observational study. Full-thickness skin biopsy specimens from fibrotic lesions or healthy skin were obtained from 10 patients with NSF, 16 patients with systemic sclerosis, 8 non-NSF hemodialysis patients, and 17 healthy participants. Patient diagnosis of NSF, systemic sclerosis, non-NSF hemodialysis patients, and healthy participants, as defined using skin biopsy. Dermal messenger RNA and protein expression of profibrotic TGF-beta, SMAD2, SMAD3, SMAD4, SMAD7, CTGF, TIMP-1, antifibrotic SMAD7, and TNF-alpha were analyzed using real-time reverse transcription-polymerase chain reaction and immunohistologic examination on formalin-embedded tissue. Dermal expression of nearly all parameters differed in hemodialysis patients compared with healthy controls. In comparison to hemodialysis patients and healthy participants, we found increased messenger RNA levels for TGF-beta, the profibrotic receptor-activated SMAD2 and SMAD3, CTGF, and TIMP-1 in NSF and systemic sclerosis lesions. Few differences between NSF and non-NSF hemodialysis patients were observed for common SMAD4, inhibitory SMAD7, and TNF-alpha. Small patient cohort. Our results suggest a profibrotic imbalance in the TGF-beta-SMAD-CTGF axis in NSF skin lesions. Significantly increased dermal expression of TGF-beta and TIMP-1 in non-NSF hemodialysis patients in comparison to healthy participants emphasizes the need for a hemodialysis control group for future investigations and suggests a pre-existing profibrotic situation in the skin of hemodialysis patients.American Journal of Kidney Diseases 06/2010; 55(6):1040-9. DOI:10.1053/j.ajkd.2010.01.021 · 5.76 Impact Factor
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ABSTRACT: Nephrogenic systemic fibrosis (NSF) is an acquired, idiopathic disorder. Most of the cases are observed in patients with end stage renal disease (ESRD). The objective of this nonclinical animal study was to test the hypothesis that gadolinium (Gd) deposits play a role in the induction of NSF lesions. In addition, we evaluated whether an acute response to Gd exposure can initiate a process that results in fibrosis of the skin. Han-Wistar rats were administered 3 intravenous injections of Gd-DTPA-BMA formulated without Gd-free excess ligand (Gadodiamide without Caldiamide) at a dose of 2.5 mmol/kg of body weight (b.w.) per injection given at 24-hour or 14-, 28-, or 56-day intervals. The occurrence and development of NSF-like fibrosing dermopathy lesions were followed. The Gd concentration was determined by Inductively Coupled Plasma Mass Spectrometry in skin biopsies taken during the study and organ samples taken at the end of the study.In a separate study, after injection of a single intravenous dose of 2.5 mmol/kg b.w. Gd-DTPA-BMA administered to Han-Wistar rats, the expression of cytokines and signaling molecules in serum and skin tissue was determined by quantitative RT-PCR and Luminex technology 6 hours or 14, 28, or 56 days. The occurrence of NSF-like macroscopic skin lesions differed between the injection groups. Shorter injection intervals resulted in more severe skin reactions. In contrast, the injection interval did not influence the long-term presence and level of accumulation of Gd concentration in tissue. The single injection of Gd-DTPA-BMA was followed by a rapid and transient induction of signaling molecules in the serum (MCP1, MCP3, IL1, IP-10, Osteopontine SCF and Timp1) as well as in the skin (MCP1 and TGFb). The presence of NSF-like fibrosing dermopathy in rats was found to be dependent on the injection interval and not on the amount of Gd in tissue. Our findings suggest the possibility of a more acute intrinsic reaction on administration of Gd-DTPA-BMA that triggers events leading to the development of skin lesions. The finding that single injections of Gd-DTPA-BMA were accompanied by a fast and transient induction of signaling molecules that are known to be involved in several fibrotic events provides additional support for this hypothesis. The study findings, however, do not support the theory that the long-term presence of Gd plays a relevant role in the development of NSF.Investigative radiology 10/2010; 46(1):48-56. DOI:10.1097/RLI.0b013e3181efd49a · 4.45 Impact Factor
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ABSTRACT: Mesangial matrix expansion is a prominent feature of the most common form of glomerulonephritis, IgA nephropathy (IgAN). To find molecular markers and improve the understanding of the disease, the gene and protein expression of proteoglycans were investigated in biopsies from IgAN patients and correlated to clinical and morphological data. We collected and microdissected renal biopsies from IgAN patients (n = 19) and from healthy kidney donors (n = 14). Patients were followed for an average time of 4 years and blood pressure was according to target guidelines. Distinct patterns of gene expression were seen in glomerular and tubulo-interstitial cells. Three of the proteoglycans investigated were found to be of special interest and upregulated in glomeruli: perlecan, decorin and biglycan. Perlecan gene expression negatively correlated to albumin excretion and progress of the disease. Abundant decorin protein expression was found in sclerotic glomeruli, but not in unaffected glomeruli from IgAN patients or in controls. Transforming growth factor beta (TGF-β), known to interact with perlecan, decorin and biglycan, were upregulated both on gene and protein level in the glomeruli. This study provides further insight into the molecular mechanisms involved in mesangial matrix expansion in IgAN. We conclude that perlecan is a possible prognostic marker for patients with IgAN. In addition, the up-regulation of biglycan and decorin, as well as TGF-β itself, indicate that regulation of TGF-β, and other profibrotic markers plays a role in IgAN pathology.PLoS ONE 04/2011; 6(4):e18575. DOI:10.1371/journal.pone.0018575 · 3.53 Impact Factor