title: Analysis of immunostaining and western blotting of endothelin 1 and its receptors in mitral stenosis.
abstract: BACKGROUND
  Rheumatic Fever represents a serious public health problem in developing countries, with thousands of new cases each year. It is an autoimmune disease, which occurs in response to infection by streptococcus A.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the immunolabeling and protein expression for endothelin-1 and 3 (ET-1, ET-3) and its receptors (ETA, ETB) in rheumatic mitral valves.
  
  
  METHODS
  Immunohistochemistry was used to identify ET-1/ET-3 and ETA/ETB receptors in rheumatic and control mitral valves. Quantitative analysis of immunostaining for ET-1/ET-3 and ETA/ETB receptors was performed. In addition, western blot analysis was carried out to assess protein levels in tissue samples.
  
  
  RESULTS
  ET-1 and ETA receptor immunostaining predominated in stenotic valves, mainly associated with fibrotic regions, inflammatory areas and neovascularization. Quantitative analysis showed that the average area with positive expression of ET-1 was 18.21 ± 14.96%. For ETA and ETB, the mean expressed areas were respectively 15.06 ± 13.13% and 9.20 ± 11.09%. ET-3 did not have a significant expression. The correlation between the expression of both endothelin receptors were strongly positive (R = 0.74, P = 0.02), but the correlation between ET-1 and its receptor were negative for both ETA (R = -0.37, P = 0.25), and ETB (R = -0.14, P = 0.39). This data was supported by western blot analysis.
  
  
  CONCLUSIONS
  The strong correlation between ET-1 and its receptors suggests that both play a role in the pathophysiology of rheumatic mitral valve stenosis and may potentially act as biomarkers of this disease.
authors.affiliation: Universidade Federal de São Paulo, São Paulo, SP, Brazil.
authors.forename: Sydney Correia
authors.initials: SC
authors.lastname: Leão
authors.affiliation: Department of Clinical Biochemistry, Medical School, University College London, London, UK.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Dashwood
authors.affiliation: Group of Molecular Anatomy, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Mateus Santana de
authors.initials: MS
authors.lastname: Andrade
authors.affiliation: Group of Molecular Anatomy, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Nicolas Nascimento
authors.initials: NN
authors.lastname: Santos
authors.affiliation: Group of Molecular Anatomy, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Olivia Regina Lins Leal
authors.initials: OR
authors.lastname: Teles
authors.affiliation: Group of Molecular Anatomy, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Williasmin Batista de
authors.initials: WB
authors.lastname: Souza
authors.affiliation: Group of Molecular Anatomy, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil.
authors.forename: Tania Maria de Andrade
authors.initials: TM
authors.lastname: Rodrigues
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D015153:Blotting, Western; D002118:Calcium / Q000032:analysis; D016022:Case-Control Studies; D019332:Endothelin-1 / Q000032:analysis*; D019334:Endothelin-3 / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008946:Mitral Valve Stenosis / Q000473:pathology* / Q000503:physiopathology; D044022:Receptor, Endothelin A / Q000032:analysis*; D044023:Receptor, Endothelin B / Q000032:analysis*; D012016:Reference Values; D012213:Rheumatic Fever / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019332:Endothelin-1; D019334:Endothelin-3; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D002118:Calcium