ECE2017 Eposter Presentations: Thyroid Thyroid (non-cancer) (260 abstracts)
Non-thyroidal illness syndrome in chronic renal failure and oxidative stress: preliminary data on triiodothyronine relationships with extracellular superoxide-dismutase
Antonio Mancini 1 , Nicola Panocchia 2 , Giuseppe Martino 1 , Carmine Bruno 1 , Sonia Silvestri 3 , Patrick Orlando 3 , Fabio Marcheggiani 3 , Luigi Tazza 2 , Luca Tiano 3 , Giovanni Gambaro 2 & Alfredo Pontecorvi 1
1Catholic University of the Sacred Heart, Operative Unit of Endocrinology, Rome, Italy; 2Fondazione Policlinico Gemelli, Nephrology Division, Rome, Italy; 3Polytechnic University of Marche, Department of Life and Environmental Sciences, Ancona, Italy.
: Non-thyroidal-illness syndrome (NTIS) is present in chronic renal failure and considered an adaptive mechanism. However oxidative stress is linked to NTIS in a vicious circle, due to deiodinases alteration and negative effect on antioxidant levels or activity. One key antioxidant, protective toward ROS-mediated tissue damage, is extracellular superoxide-dismutase (ec-SOD), present in extracellular matrix and with a role in mediating nitric oxide-induced signaling. ec-SOD is specifically released from endothelium by heparin injection, allowing the determination of ec-SOD activity in vivo without affecting Cu,Zn-SOD or Mn-SOD. No data are reported on ec-SOD in renal failure and its relationship with thyroid function. Therefore we have studied 12 hemodialysis patients (9 males and 3 females, mean age 67 ys), evaluating thyroid hormones and ec-SOD activity after enoxaparin administration. Blood samples were obtained at the starting of hemodialytic session, 5 and 10 min after 1000–4000 U enoxaparin and at the end of the session. SOD activity was measured by a modified nitrite method. Superoxide generated by hypoxanthine and xanthine oxidase was changed by hydroxylamine to nitrite ion which was measured spectrophotometrically at 550 nm by the use of a chromogen. The amount of SOD required to inhibit 50% nitrite ion generation was defined as 1 U SOD activity. Six patients exhibited low fT3 values (1.8±0.1 pg/ml); the others had normal fT3 (2.5±0.2 pg/ml); fT4 and TSH values were normal. Basal eC-SOD did not differ between the two groups, but the percentual increase after heparin was significantly correlated with T3 levels (r=0.24, P<0.05). These preliminary data suggest that low T3 can negatively influence endothelial antioxidant defenses. The relationships of this datum with cardiovascular complications and prognostic usefulness remain to be established.
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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