Akinci Baris, Comlekci Abdurrahman, Yener Serkan, Demir Tevfik, Ozcan Mehmet Ali, Bayraktar Firat, Yesil Sena
Division of Endocrinology and Metabolism, Department of Internal Medicine, Dokuz Eylul University Medical School, Izmir, Turkey.
Endocr J. 2007 Aug;54(4):593-9. doi: 10.1507/endocrj.k06-176. Epub 2007 Aug 10.
Both increased and decreased fibrinolytic activity have been reported in patients with hyperthyroidism. Elevated levels of plasma plasminogen activator inhibitor-1 (PAI-1) antigen have been found in hyperthyroid patients. Thrombin activatable fibrinolysis inhibitor (TAFI) is a novel plasma protein, which inhibits fibrinolysis through removal of C-terminal lysines from partially degraded fibrin. Previously, we showed that plasma TAFI antigen levels were increased in patients with overt and subclinical hypothyroidism. The aim of this study is to investigate plasma levels of TAFI and PAI-1 antigens in hyperthyroid patients. PAI-1 and TAFI antigen levels were measured in the plasma of 29 patients with hyperthyroidism (14 overt hyperthyroid and 15 subclinical hyperthyroid), and 26 healthy individuals. Although there were increased levels of PAI-1 antigen in hyperthyroid patients, plasma TAFI antigen levels were significantly lower compared to controls (80.79 ng/ml vs. 32.42 ng/ml, p = 0.000 for PAI-1; 10.42 microg/ml vs. 12.24 microg/ml, p = 0.009 for TAFI). Elevated PAI-1 antigen levels were positively correlated with free thyroid hormones, although TAFI antigen levels were in negative correlation with free thyroxine. Furthermore, an inverse correlation between PAI-1 and TAFI antigen levels was found. Our study demonstrated that TAFI antigen levels were decreased in patients with hyperthyroidism. Inverse correlation with PAI-1 suggests that the decrease in TAFI antigen levels may be due to activation of TAFI pathway. Further studies evaluating the underlying mechanisms of low TAFI antigen levels in hyperthyroidism should be undertaken.
甲状腺功能亢进症患者中既有纤溶活性增加的报道，也有纤溶活性降低的报道。甲状腺功能亢进症患者血浆纤溶酶原激活物抑制剂-1（PAI-1）抗原水平升高。凝血酶激活的纤溶抑制物（TAFI）是一种新型血浆蛋白，它通过从部分降解的纤维蛋白中去除C末端赖氨酸来抑制纤溶。此前，我们发现显性和亚临床甲状腺功能减退症患者血浆TAFI抗原水平升高。本研究的目的是调查甲状腺功能亢进症患者血浆TAFI和PAI-1抗原水平。测定了29例甲状腺功能亢进症患者（14例显性甲状腺功能亢进和15例亚临床甲状腺功能亢进）及26名健康个体血浆中的PAI-1和TAFI抗原水平。尽管甲状腺功能亢进症患者PAI-1抗原水平升高，但与对照组相比，血浆TAFI抗原水平显著降低（PAI-1：80.79 ng/ml对32.42 ng/ml，p = 0.000；TAFI：10.42 μg/ml对12.24 μg/ml，p = 0.009）。PAI-1抗原水平升高与游离甲状腺激素呈正相关，而TAFI抗原水平与游离甲状腺素呈负相关。此外，还发现PAI-1与TAFI抗原水平呈负相关。我们的研究表明，甲状腺功能亢进症患者TAFI抗原水平降低。与PAI-1呈负相关表明TAFI抗原水平降低可能是由于TAFI途径激活所致。应进一步开展研究评估甲状腺功能亢进症患者TAFI抗原水平降低的潜在机制。
