title: Relationship between interleukin-6 and cardiac involvement in systemic sclerosis.
abstract: OBJECTIVE
  To explore the relationship between IL-6 levels and echocardiographic abnormalities, and N-terminal probrain natriuretic peptide (NT-proBNP) levels in SSc patients and to correlate tested parameters with European Scleroderma Activity (EUSTAR) score.
  
  
  METHODS
  This case-control study included 31 SSc patients with preserved left ventricular ejection fraction (LVEF) and 32 matched healthy controls. Serum IL-6 and NT-proBNP levels were measured and subjects were evaluated by conventional and pulsed-wave tissue Doppler echocardiography.
  
  
  RESULTS
  The level of IL-6 was significantly increased in patients with SSc (3.2 vs 2.2 pg/ml, P < 0.001). SSc patients had significantly lower values of LV systolic (7.7 vs 9.25 cm/s, P < 0.001) and early diastolic (8.7 vs 10.3 cm/s, P = 0.014) myocardial velocities and higher E/e' (9.04 vs 7.37, P = 0.001) ratio, although there was no between-group difference according to LVEF (68% vs 65%, P = 0.248). On evaluating the right ventricle there was no significant between-group difference in systolic tricuspid annular velocity (13 vs 13.9 cm/s, P = 0.105), but the peak early diastolic velocity was significantly lower (11.7 vs 13.6, P = 0.044) and E/e' was significantly higher (4.3 vs 3.38, P = 0.008) in SSc patients. IL-6 level showed correlation with LV mean e' (r = -0.57, P = 0.001), E/e' (r = 0.55, P = 0.001) and NT-proBNP (r = 0.52, P = 0.003). EUSTAR score correlated with LV E/e' (r = 0.48, P = 0.006), mean e' (r = -0.67, P < 0.001), mean s' (r = -0.51, P = 0.004), NT-proBNP (r = 0.60, P < 0.001) and IL-6 (r = 0.79, P < 0.001).
  
  
  CONCLUSIONS
  IL-6 level is increased in patients with SSc and significantly correlates with LV diastolic dysfunction, NT-proBNP and EUSTAR score. These results support the role of IL-6 in the development of cardiac disease in SSc patients.
authors.affiliation: Department of Cardiology, University Hospital Center Split, Spinciceva 1, 21 000 Split, Croatia. zrinkacn@gmail.com
authors.forename: Zrinka
authors.initials: Z
authors.lastname: Jurisic
authors.forename: Dusanka
authors.initials: D
authors.lastname: Martinovic-Kaliterna
authors.forename: Daniela
authors.initials: D
authors.lastname: Marasovic-Krstulovic
authors.forename: Dijana
authors.initials: D
authors.lastname: Perkovic
authors.forename: Leida
authors.initials: L
authors.lastname: Tandara
authors.forename: Ilza
authors.initials: I
authors.lastname: Salamunic
authors.forename: Vedran
authors.initials: V
authors.lastname: Carevic
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D012595:Scleroderma, Systemic / Q000097:blood / Q000503:physiopathology*; D012720:Severity of Illness Index; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology; D016278:Ventricular Function, Right / Q000502:physiology
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D015850:Interleukin-6; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain
keywords: cardiac involvement; interleukin-6; systemic sclerosis; tissue Doppler echocardiography