The role of cytokines and cortisol in the non-thyroidal illness syndrome following acute myocardial infarction

Abstract

Objective: A number of different hormone changes have been described during the acute myocardial infarction (AMI), including those of the non- thyroidal illness syndrome (NTIS). Design and methods: We assessed the alterations of serum thyroid hormones, cytokines and cortisol levels in 30 patients with a first episode of AMI 4, 24, 48 h and 10 days (240 h) after the onset of the chest pain and we investigated the possible relationship of these alterations with the severity of AML Results: Fifteen patients had left ventricular ejection fraction (LVEF) ≤ 50% (group I) and 15 patients had LVEF > 50% (group II). A transient decrease of total tri-iodothyronine (T3), more prominent in group I (P < 0.05, t-test) with a concomitant rise of reverse T3 (rT3) occurred at 24 h. Total thyroxine (T4), free T4 (FT4) and free T4 index did not change significantly, but tended to be higher in group I patients, whereas TSH significantly increased in group II at 48 h. Interleukin-6 (IL-6) increased significantly at 24 h only in group I and declined thereafter (24 vs 240 h, P < 0.001) and this temporal change of IL-6 was associated with similar changes of creatine phosphokinase and creatine kinase isoenzyme MB (CK-MB). Tumor necrosis factor-α and IL-1β remained low in both groups. Cortisol was higher at 4 h and in 12 patients was above the normal values. Negative correlation was found between LVEF and IL-6 (P< 0.001), whereas T3, T4 or cortisol levels were not correlated with the LVEE Conclusions: Our data indicate that NTIS, in association with increase of IL- 60 occurs in the early postinfarction period. In the NTIS following AMI the high level of IL-6 is the best predictor, among several parameters, of the severity of AMI as assessed by the LVEF and the rise of CK-MB.