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Scheda a cura di Marco Chilosi (GYM)
TENASCINA**
marcatore di fibrogenesi
figura 1. intensa espressione di tenascina nei foci fibroblastici della UIP (fibrosi polmonare idiopatica)
Am J Respir Crit Care Med. 1996 Aug;154(2 Pt 1):511-8. Tenascin immunoreactivity as a prognostic marker in usual interstitial pneumonia. Kaarteenaho-Wiik R, Tani T, Sormunen R, Soini Y, Virtanen I, Paakko P. Department of Pathology, University of Oulu, Finland. In this investigation, tenascin (Tn) expression was studied in 51 cases of different types of fibrotic lung disorders originating for years 1981 to 1995. Our aim was to test if accumulation of Tn at the site of lung injury in usual interstitial pneumonia (UIP) could correlate with the prognosis. Lung biopsies taken from 28 patients with UIP, six with desquamative interstitial pneumonia (DIP), six with sarcoidosis, five with extrinsic allergic bronchioloalveolitis, five with bronchiolitis obliterans organizing pneumonia (BOOP), and one with nonspecific interstitial pneumonia were studied for the expression of Tn by using an immunohistochemical technique. In addition to Tn immunohistochemistry, selected cases were also studied by immunoelectron microscopy and Western blotting. For prognostic studies in UIP the clinical follow-up information was obtained from the patient records. The expression of Tn was increased in each type of fibrosis, especially in UIP. In immunoelectron microscopy the most prominent labeling in UIP was found in association with collagen fibers and within the type 2 pneumocytes. Every studied case of UIP showed reactivity for a polypeptide of M(r) approximately equal to 200,000 by Western blotting. In patients with UIP, increased Tn expression, especially under metaplastic bronchiolar-type epithelium, was associated with a shortened survival time. Immunoelectron microscopic findings support the idea that Tn in UIP is synthesized by the regenerating epithelial rather than interstitial cells in response to pulmonary interstitial inflammation.
J Pathol. 1995 Apr;175(4):415-20. Tenascin immunoreactivity in cryptogenic fibrosing alveolitis. Wallace WA, Howie SE, Lamb D, Salter DM. Department of Pathology, Edinburgh University Medical School, U.K. Tenascin is a hexameric extracellular matrix (ECM) glycoprotein which has been demonstrated to have a temporal relationship with active scar formation in adult tissues. We hypothesized that this ECM protein might therefore serve to identify areas of active scarring in lung biopsies from patients with cryptogenic fibrosing alveolitis (CFA). The distribution of tenascin was examined in open lung biopsies from ten patients with CFA, six patients with sarcoidosis, and six pulmonary resection specimens from patients with no evidence of interstitial lung disease, using an immunohistochemical technique. Immunoreactive tenascin was not identified in histologically normal control lung parenchyma and was only focally found around large aggregates of granulomas in sarcoidosis. In the CFA, tenascin production was demonstrated in minimally damaged alveolar walls and areas of active disease but not in end-stage scarred lung. There was considerable local heterogeneity of staining within cases, which did not appear to relate to the density of the local inflammatory infiltrate. Large plaques of tenascin were noted to be particularly associated with hyperplastic type II alveolar epithelial lining cells, which are recognized to produce fibrogenic cytokines. The examination of tenascin expression in open lung biopsies from patients with CFA may be useful in assessing fibrogenic activity and may thus provide additional prognostic information.
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